Byte Magazine Volume 06 Number 05 - Software Piracy (RESCAN)

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YOUR CHOICEI-smart either way

• Over 140 software driven functions

• 82 X 24 or 82 x 20 screen format — software selectable

• High resolution 7x12 matrix characters — P-31 green phosphor

• Upper/lower case character set — plus graphics character set

• 56-key alphanumeric keyboard — plus 12-key cursor, numeric pad

• Internal editing functions — insert, delete, scroll, roll, slide, etc.

• Parallel printer I/O port

• 50 to 38,400 baud operation — programmable

• Cursor type, cursor position, print control characters, protected fields, shift inversion, dual intensity and many other features

8212 — twelve-inch diagnonal screen or 8209 — nine-inch diagnonal screen

SOUTHWEST TECHNICAL PRODUCTS CORPORATION 219 W. RHAPSODY

SAN ANTONIO, TEXAS 78216 (512) 344-0241

Circle 382 on inquiry card.

EXPANDABLE I/O BUS

I/O INTERFACES

COLOR GRAPHICS

MULTIPROCESSING

IVMBYTE HARD DISK DRIVE

EXTENSIVE SOFTWARE SUPPORT

What Cromemco computer card capability can do for you

The above diagram shows in a functional way one of the most complete lines of computer cards in the industry.

Lool< it over carefully. It could be well worth your while.

These are all cards that plug into our S-100 bus microcomputers.

You can also assemble them into a custom system in convenient Cromemco card cages.

MULTI-PROCESSING AND INTELLIGENT I/O

The range of capabilities and versatility you can draw upon is enormous.

In processors, for example, you have a choice of CPU's including our extremely useful new I/O Processor. This can be used as a satellite processor to do off-line processing, multi-processing, and to form intelligent I/O. It opens the door to a whole new group of applications and tasks. Ask us about it.

HIGH RESOLUTION COLOR GRAPHICS

Again, you can have beautiful highresolution color graphics with our color graphics interface. You can select from over 4000 colors and have a picture with a resolution at least equal to quality broadcast-TV pictures.

You have an unprecedented selection of memory including our unusual 48K and 16K two-port RAMs which allow high-speed color graphics.

LOTS OF STORAGE

These days you often want lots of disk storage. So you can select from our disk controller card which will operate our 5" and 8" floppy disk drives (up to 1.2 megabytes). Or select our WDI interface to operate our 11-megabyte hard disk drives.

POWERFUL SOFTWARE AND PERIPHERAL SUPPORT

There's much more yet you can do with our cards. And, of course, there's an easy way to put them to work in our 8-, 12-, and 21-slot card cages. Our PS8 power supply makes it simple to get the system into operation.

Finally, Cromemco offers you the strongest software support in the industry

with languages like FORTRAN, C, COBOL, ASSEMBLER, LISP, BASIC and others. There is also a wide choice from independent vendors.

To top it all off, you can draw from a substantial array of peripherals: terminals, printers, color monitors and disk drives.

CONTACT YOUR CROMEMCO REP

There is even more capability than we're able to describe here.

Contact your Cromemco rep now and get this capability working for you.

CROMEMCO COMPUTER CARDS • PROCESSORS — 4 MHz Z-80 A CPU, single card computer, I/O processor • MEMORY — up to 64K including special 48K and 16K twoport RAMS and our very well known BYTESAVERS* with PROM programming capability • HIGH RESOLUTION COLOR GRAPHICS — our SDI offers up to 754 x 482 pixel resolution. • GENERAL PURPOSE INTERFACES —QUADART four-channel serial communications, TU-ART two-channel parallel and two-channel serial, 8PIO 8-port parallel, 4PIO 4-port isolated parallel, D-I-7A 7-channel D/A and A/D converter, printer interface, floppy disk controller with RS-232 interface and system, diagnostics, wire-wrap and extender cards for your development work.

Cromemco

TM

^^^^^ 280 BERNARDO AVE., MOUNTAIN VIEW, CA 94040 • (415)964-7400

Tomorrow's computers today

Circle 105 on Inquiry card.

.1

i

Management Information Display

Ultrasonic heart sector scan

High-resolution display with alphanumerics

Get the professional color

display that has BASIC/FORTRAN simplicity

LOW-PRICED, TOO

Here's a color display that has everything: professional-level resolution, enormous color range, easy software, NTSC conformance, and low price.

Basically, this new Cromemeo Model SDI* Is a two-board interface that plugs into any Cromemeo computer.

The SDI then maps computer display memory content onto a convenient color monitor to give high-quality, highresolution displays (756 H x 482 V pixels).

When we say the SDI results in a highquality professional display, we mean you can't get higher resolution than this system offers in an NTSC-conforming display.

The resolution surpasses that of a color TV picture.

BASIC/FORTRAN programming

Besides its high resolution and low price, the new SDI lets you control with optional Cromemeo software packages that use simple BASIC- and FORTRANlike commands.

Pick any of 16 colors (from a 4096-color palette) with instructions like DEFCLR (c, R, G, B). Or obtain a circle of specified size, location, and color with XCIRC (X, y, r, c).

•U.S. Pat. No. 4121283

Model SDI High-Resolution Color Graphics Interface

HIGH RESOLUTION

The SDI's high resolution gives a professional-quality display that strictly meets NTSC requirements. You get 756 pixels on every visible line of the NTSC standard display of 482 image lines. Vertical line spacing is 1 pixel.

To achieve the high-quality display, a separate output signal is produced for each of the three component colors (red, green, blue). This yields a sharper image than is possible using an NTSC-composite video signal and color TV set. Full image quality is readily realized with our highquality RGB Monitor or any conventional red/green/blue monitor common in TV work.

Model SDI plugs into Z-2H 11-megabyte hard disk computer or any Cromemeo computer

DISPLAY MEMORY

Along with the SDI we also offer an optional fast and novel two-port memory that gives independent high-speed access to the computer memory. The two-port memory stores one full display, permitting fast computer operation even during display.

CONTACT YOUR REP NOW

The Model SDI has been used in scientific work, engineering, business, TV, color graphics, and other areas. It's a good example of how Cromemeo keeps computers in the field up to date, since it turns any Cromemeo computer into an up-to-date color display computer.

The SDI has still more features that you should be informed about. So contact your Cromemeo representative now and see all that the SDI will do for you.

Cromemeo

incorporated

280 BERNARDO AVE., MOUNTAIN VIEW, CA 94043 • (415) 964-7400

Tomorrow's computers today circle 105 on inquiry card.

In The Queue

Volume6, Numbers

May 1981

Features 36

Extended Color BASIC for the TRS-80 Color Computer by Stan Miastkowski / Fast, easy, and inexpensive graphics are finally available for personal computers with this new system from Radio Shack.

46

The Commodore VIC 20 Microcomputer: A LowCost, HIgh-Performance Consumer Computer by Gregg Williams / The VIC 20 has color, sound, graphics, and expandability, and sells for S299.95.

66 DC Motor Controls: Build a Motorized Platform by

Steve Ciarcia / Appropriate circuits can very precisely control permanentmagnet DC motors.

128 Washington Tackles the Software Problem by

Christopher Kern / Recent court decisions pave the way for more software protection against piracy.

Legal Protection for Computer Hardware and Software by Stephen A Becker / An overview of patents, copyrights, and trade secrets, and how they relate to computer software and hardware protection.

152 WIre-WrappIng and Proto-System Techniques by

Adolph Mangier'! I Construction of homebrew designs is greatly aided by the complete wire-wrapping systems from Vector Electronics.

171 Speeding Up TRS-80 Graphics by Ronald Bobo and John Knoderer / Improve the response time of BASIC graphics displays on your TRS-80.

204 An Integer Math Package for the 8080 by Bruce D Carbrey / These routines are useful when you need arithmetic operations on signed 16-bit numbers.

280

Using Interrupts on the Apple II System by George

M White / The use of interrupts in the 5502 microprocessor is demonstrated using an Apple II.

296 Digital Plotting with the Apple II Computer by

Richard C Hallgren / Interface an x.y plotter directly to an Apple II with a minimum of hardware.

316 Recursion and Side Effects In Pascal by Robert

Morris / The use of global and local variables can change how a program works.

326

DEMONS: A Symbolic Debugging Monitor by A I

Halsema / Debug your machine-language programs for 6800-based systems using instruction mnemonics.

360 Build a Super Simple Floppy-Disk Interface, Part 1

by James fMicholson and Roger Camp / Ten integrated circuits can provide all the features of a commercial disk controller at a fraction of the cost.

408 A File Catalog System for UCSD Pascal by Edward

Heyman / Keep track of all those scattered files with this organization

system.

436 IMumerical Methods In Data Analysis by Toan c

Nguyen / Gauss-Jordon elimination and the Newton-Raphson method can be used to find the function curve that best fits a set of empirically determined data.

Reviews

22 The Epson IVlX-80 and MX-70 Printers by Kevin Cohan

1 06 BYTE's Arcade: Star Raiders by Gregg Williams; Super Nova by Bob Liddil. Tranquility Base by Robin Moore. Asteroids in Space and Planetoids by Oliver Holt

148 Dancing Demon from Radio Shack by Elizabeth Cooper and Yvon Kolya

248 Super STEP by Stanley D Robbins 254 U/ordsmith by Mark Dahmke

Nucleus

6 12 102,

)22,

126 186 198

228,

232, 244,

262

278,

384

394

398

404

447

463

510

511

512

Editorial. How Can We Stop Software Piracy? Letters

236 System Notes: Improve TRS-80 Disk Operation: Add an External Data Separator; Faster BASIC for the Ohio Scientific

430 Programming Quickies: Using Page Two with Apple Pascal Turtle

Graphics: Printf for the C Function Library

Cartoon

Education Forum: Getting Problem-Solving Advice From a Computer Desk-Top Wonders: A Chessboard Journey on the TI-59 Programmable Calculator

378, 452, 458 Technical Forum: Print Your Own Bar Codes: UPC Bar Codes With the Centronics 737: PAPERBYTE* Bar Codes with Integral Data Systems Printers; Favori[e Benchmarks and Other Programs; Build a NoiseBased Random-Number Generator: Fast Fourier Comes Back 252 BYTE's Bugs

380 Book Reviews: Principles of Interactive Computer Graphics. 2nd

Editjon; Travels in Computeriand. or incompatibilities & Interfaces

BYTELINES

428 BYTE'S Bits

Ask BYTE

Software Received

Books Received

Clubs and Newsletters

Event Queue

What's New?

Unclassified Ads

BOMB. BOMB Results

Reader Service

CliTE

nCri.A

i?6ATA PRECiaiDN dcv OFF . j

^^^^^

Page 36

Page 46

Page 66

Page 106

May 1981 © BYTE Publications Inc 3

Editor in Chief Christopher Morgan

Managing Ed/tor

Mr^rk H^cis

Technical Editors

Gregg Williams, Senior Editor:

Richard S Shuford; Curtis P Feigel:

Harold Nelson: Stan Miastkowski:

Kevin Cohan: Charles Freiberg,

New Products Editor:

Steve Ciarcia. Mark Dahmke,

Consulting Editors:

Jon Swanson, Draftsman

Copy Editors

Richard Friedman, Chief: Faith Hanson: Warren Williamson: Anthony J Lockw/ood: Ann Graves

Assistants

Faith Ferry: Debe Wheeler: Karen A Cilley

Production

Nancy Estle, Director: Christine Dixon, Asst Director: Wai Chiu Li: Deborah Porter: Jonathan M Graves: Patrice Scribner: Sherry McCarthy, Chief Typographer: Debi Fredericks: Donna Sweeney: Valerie Horn

Advertising

Thomas Harvey, Director: Marion Gagnon: Barbara J Greene: Rob Hannings

Circulation

Gregory Spitzfaden, Manager: Andrew Jackson, Asst Manager: Agnes E Perry: Barbara Varnum; Louise Menegus: Bill Watson: Dealer Sales: Melanie Bertoni

Marketing

Jill E Callihan, Special Projects: Laura Hanson

Controller's Office

Daniel Rodrigues, Controller: Mary E Fluhr, Asst Controller: Karen Burgess: Jeanne Cilley: Mary Beth Ireland

Traffic

N Scott Gagnon: Robert A Fiske

Receptionist

Jacqueline Earnshaw

Publishers

Virginia Londoner: Gordon R Williamson: John E Hayes, Associate Publisher: Cheryl A Hurd, Publisher's Assistant

Officers of McGraw-Hill Publications Company; Paul F McPherson. President: Executive Vice Presidents: James E Boddorf, Gene W Simpson: Group Vice President: Daniel A McMillan: Senior Vice President-Editorial: Ralph R Schuiz: Vice Presidents: Kemp Anderson, Business Systems Development: Robert B Doll, Circulation: James E Hackett, Controller: Eric B Herr, Planning and Development: H John Sweger, Marketing.

Officers of the Corporation: Harold W McGraw Jr. President, Chief Executive Officer and Chairman of the Board: Robert F Landes, Senior Vice President and Secretary: Ralph J Webb, Treasurer,

In This Issue

Did you know that the Vikings were notorious pirates? In Robert Tinney's striking cover painting, executed from an original design by Jonathan Graves, the floppy disk is the "sail" that powers the underhanded business of software piracy. Included are several articles on the legal aspects of protecting software from unscrupulous pirates; Chris Morgan's editorial, "How Can We Stop Software Piracy?" (page 6); Christopher Kern's "Washington Tackles the Software Problem" (page 128), and Stephen A Becker's "Legal Protection for Computer Hardware and Software" (page 140).

Other noteworthy articles in this issue include in-depth examinations of the Extended Color BASIC for the TRS-80 Color Computer, the new Commodore VIC microcomputer, and the Epson MX-70 and MX-80 printers. And this issue begins a new occasional feature on microcomputer video games called "BYTE's Arcade."

BYTE IS published monthly by BYTE Publications Inc. 70 Mam St, Peterborough NH 03458, phone |603| 924-9281, a wholly-owned subsidiary of McGraw-Hill, Inc, Address subscriptions, change of address, USPS Form 3579, and fulfillment questions to BYTE Subscriptions, POB 590, Martinsville NJ 08836. Controlled circulation postage paid at Waseca, Minnesota 56093 - USPS Publication No, 528890 (ISSN 0360-5280), Canadian second class registration number 932 i, Subscriptions are S19 for one year, S34 for two years, and S49 for three years in the USA and its possessions. In Canada and Mexico. S21 for one year, S38 for two years, S55 for three years. S43 for one year air delivery to Europe, S35 surface delivery elsewhere. Air delivery to selected areas at additional rates upon request. Single copy price is S2.50 in the USA and its possessions, S2.95 in Canada and Mexico, S4 00 in Europe, and S4.50 elsewhere. Foreign subscriptions and sales should be remitted in United States funds drawn on a US bank. Printed In United States of America.

Address all editorial correspondence to the editor at BYTE. POB 372. Hancock NH 03449, Unacceptable manuscripts will be returned il accompanied by sufficient first class postage. Not responsible for lost manuscripts or photos. Opinions expressed by the authors are not necessarily those of BYTE. Entire contents copyright © 1981 by BYTE Publications Inc. All rights reserved. Where necessary, permission is granted by the copyright owner for libraries and others registered with the Copyright Clearance Center (CCC) to photocopy any article herein for the base fee of S1.00 per copy of the article or item plus 25 cents per page. Payment should be sent directly to the CCC, 21 Congress St, Salem MA 01970. Copying done for other than personal or internal reference use without the permission of McGraw-Hill is prohibited Requests for special permission or bulk orders should be addressed to the publisher.

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i Hajar Associates

Hajar Associates

Hajar Associates

\ 280 Hillside Ave

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Needham Heights MA 02194

Skokie IL 60076

New York NY 10017

NORTHWEST (415) 964-0706

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Hajar Associates

Hajar Associates

Hajar Associates

1000 Elwell Ct, Suite 227

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Palo Alto CA 94303

Suite K-4

Apopka FL 32703

Cosla Mesa CA 92626

4 May 1981 © BYTE Publications Inc

. .stands well above other S-100 graphics displays in its price and performance range."

. better . display.

monochromatic

BYTE, Product Review

ELECTRONIC DESIGN, 1981 Technology Forecast

RS-170 composite or direct drive output

Local or external sync generation

4MhzZ80 microprocessor

60 hertz realtime clock

8 level interrupt tie-in

IEEE SI00 bus compatible

MICROANGELO

fflGH RESOLUTION GRAPHICS SINGLE BOARD COMPUTER

512 X 480 resolution black and white and vivid color displays

Light pen interiace

Time multiplexed refresh

4K resident Screenware™ Pak I operating system

32K RAM isolated from host address space

High speed communications over parallel bus ports

Screenware™ Pak I

A 4K byte operating system resident in PROM on MicroAngelo™. Pak I emulates an 85 character by 40 line graphics terminal and provides over 40 graphics commands. Provisions exist for user defined character sets and directly callable user extensions to Screenware™ Pak I.

Screenware™ Pak II

An optional software superset of Pak I which adds circle generation, polygon flood, programmable split screen for separate graphics and terminal I/O, relative coordinates, faster vector and character plotting, a macro facility, full UCSD Pascal compatibility, and more.

And now.. .COLOR!!

The new MicroAngelo™ Palette board treats from 2 to 8 MicroAngelos as "bit planes" at a full 512 X 480 resolution. Up to 256 colors may be chosen from 16.8 million through the programmable color lookup table. Overlays, bit plane precedence, fade-in, fade-out, gray levels, blinking bit plane, and a highly visual color editor are standard.

SCION

8455-D Tyco Road • Vienna. Virginia 22180 • TWX: 710-831-9087 • (703) 827-0888

Circle 358 on inquiry card.

Editorial

Circle 126 on inquiry card.

When you don't have ten thousand people and a few thousand years in your budget, you need MILE5T0ME".

Witfi today's concerns about increasing costs and declining productivity it's true more ttian ever ttiat dny project vi/orth doing deserves careful planning. Wtiettier you're planning a construction project or the opening of a new retail store, you must carefully sctiedule your manpower, dollars and time in order to maximize productivity.

MILESTONE is a criticdi-patfi-networkanalysis program, it runs on a desi<top microcomputer. Is inexpensive and simple enougti for onyone to use,

For MILESTONE o project is simply any task made up of steps ttiat must be performed in sequence. After dividing a project into it's composite steps, MILESTONE can tieip you plan, scliedule and control ttie project.

MILESTONE treats your project as a series of activities, Eacti activity tias a name, duration, capltol cost, mix of monpower, and an associated list of ottier activities ttiat must be completed first. The list of associated activities provides a thread that MILESTONE uses to link ail the jobs together Into an overall project schedule. Ever/time you odd a new activity or make change to an existing one, the entire schedule Is recomputed and the results are Immediately redisplayed on the screen,

MILESTONE requires 48K RAM & CP/M, Also available for Apple Pascal or UCSD Pascal Operating System. Formats: 8" single density IBM soft-sectored, NorthStar DD, MIcropolls Mod 11, Superbrain 3.0, Apple 11. Price is S295. Manual alone—S30. Add S7.00 for shipping.

SOFTWARE SOFTWARE DIGITAL MARKETING

DIGITAL MARKETING

2670 CHERRY LANE WALNUT CREEK • CA 94596 (415) 938-2880

Rt-seacn i.^.st) traceirCTk Pegefits university CA ^co? ^6u-\ ii

How Can We Stop Software Piracy?

Chris Morgan, Editor in Chief

Software piracy is rapidly becoming a major problem in the personal computer field. The casual copying of programs by computer hobbyists, although not at the epidemic stage, is frighteningly commonplace. Many people fail to see (or prefer not to see) that the practice is not just illegal—it's unethical.

But what about making backup copies of important software? What happens if your small business' direct-mail program "dies"? Without a backup, a businessman's only recourse is to return the disk to the manufacturer and hope it won't take longer than a few weeks to get a replacement. Manufacturers understand the problem, and have designed some floppy-disk-based programs that allow the user to make one backup copy. After this, software "jamming" information is automatically added to the original floppy disk to theoretically prevent additional illegal copies. In practice, though, enterprising software experts can crack the protection mechanisms and make copies at will.

The industry is faced with a dilemma: how does the manufacturer serve the customer's legitimate need to make backup copies, while protecting his expensive software investment? There are two possibilities: put the would-be software pirate at a disadvantage if he makes an illegal copy, or, better still, make it virtually impossible for the pirate to make a copy.

The Persuasion Route

Let me make a not-too-perfect analogy between the software industry and the record industry. When tape recorder sales began to increase during the early 1970s, record industry executives predicted that record sales would plummet because of private off-the-air taping. But, in fact, record sales climbed steadily throughout the decade. Why? My opinion is that when people think of a recording, they think of the entire package: the album artwork, the liner notes—in short, there is more to a recording than the sound coming from a pair of loudspeakers. In much the same vein, there is more to a piece of software than the object code: there is the documentation, for instance.

The need to make a copy of the documentation is an additional nuisance for the software pirate. It costs money to make photocopies. Then there's the registration card: legitimate owners of software are often put on mailing lists to receive updates to their programs as well as information about new programs from the manufacturer. A cheap and effective way for manufacturers to fight the pirate is to creatively exploit the latter idea. At the risk of overgeneralization, computer-science people tend to be obsessive-compulsive in their psychological makeup, ie: they hate to miss out on any details about a product they buy—especially a piece of software!

I mentioned earlier that this was a less-than-perfect analogy. The problem is that a $9.95 recording is one thing—a $600 program is quite another. The above-mentioned tactics might help the manufacturer of a $30 or $50 piece of software, but temptation becomes powerful indeed when the price tag reaches three or four figures.

Editorial continued on page 10

6 May 1981 © BITTE Publications Inc

Introducing the COLOR CONNECTION

Plug A TRS-80* Color Computer into the World of System-SO" Computing.

Now you can expand Tandy's exciting new TRS 80* Color Computer using proven System-50 products. Expansion possibilities are limitless. And expansion is easy. Plug one end of the COLOR CONNECTION into the Program Pak* connector of the Color Computer. Plug the other end into a System-50 bus motherboard. Now add the functions you want, selecting from an inventory of standard modules manufactured by competent, long-established firms — from the inventory of solid performers, like P£rcom Data Company.

Mini-disk storage — today!

Available off-the-shelf for your extended system is Percom's fieldproven LFD mini-disk system. The first choice of knowledgeable 580X computerists since 1977. Percom LFD mini-disk systems come complete, ready to plug in and run. File storage capacities range from 102 Kbytes for a one-drive LFD-400'" system to almost 0.6 Mbyte for a three-drive LFD- 800™ system.

Get serious!

For serious computing like word processing add the Percom ELECTRIC WINDOWS This memory-mapped video display card features instant display updating, softwaredefined full display formatting — up to 80 characters by 24 lines, an extendable character generator that generates fullyformed upper and lower case characters, and more. The ELECTRIC WINDOW provides either composite or separate sync-video output, and interfaces a standard black-&white video display monitor.

Beyond 16K

Another option

System Requirements

The COLOR CONNECTION interfaces a TRS-80* Color Computer to a System50 bus motherboard. Power for the COLOR CONNECTION is obtained from the computer. Power for the extended bus cards must be provided by an external source, such as Percom's System-50 Power Supply The COLOR CONNECTION provides for disabling the computer internal memory at 8-Kbyte boundaries to prevent contention with external memory.

The COLOR CONNECTION $99.95

is incremental memory expansion. Add 8-, 16- or 24-Kbytes of static RAM with our M24SS card; 16-, 32- or 48-Kbytes of dynamic RAM with our M48DSS card. The COLOR CONNECTION prevents contention between internal computer memory and external memory.

The right motherboard

Fast mini-disk storage, full-format alphanumerics and memory add-on are obvious expansion possibilities. The optional Percom System-50 Motherboard allows you to consider the less obvious. This seven-slot motherboard not only can be self-extended, but also can be extended with our 30-pin I/O motherboard. The richness of readily available peripheral interface cards provides an uncommon degree of expansion flexibility.

The System-50 (SS-50) bus community With a TRS-80^'' Color Computer and the COLOR CONNECTION, it's your worid. Enjoy!

Quality Percom products are available at Percom dealers nationwide. Call toll-free, 1-800-527-1592, for the address of your nearest dealer, or to order direct from Percom.

PRICES AND SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE PRICES DO NOT INCLUDE SHIPPING AND HANDLING.

trademark of Percom Data Conipanv. Inc * trademark of Tandy Radio Shack Corporation which has no ri^lationship to Pi-'rconi Data Company.

PERCQM DATA COMPANY. INC.

211 N. KIRBY GARLAND. TEXAS 75042 (214) 272-3421

Circle 321 on inquiry card.

f OR ANY € rt^ERE IS A 8*

WHnETONE MAINFRAME DEFINE

OUR Wetl-DIFFERENTIATep AREGMCULATEP SYSreMS INTKRATION

A simple algorithm

We work with the serious systems integrator... on terms that make sense to you. That means giving you a set of products which expand your limits, not reduce them.

We manufacture the most complete family of high quality IEEE/696 S-100 mainframes on the market. Choices include three mainframes in rack-mount or table-top packages with complete board sets, to serve as the building blocks for your 8 or 16 bit system. We also provide other options ranging from complete floppy disk systems right up to our proven Pascal development system.

The S factor: one source.

No matter which option you choose, you get the benefit of working with completely integrated products ... fully assembled and tested ... under one warranty and one price structure ... leaving you free to concentrate on value-added application development and sales.

Choose from mainframe options...

Select from three packaging options: Rack-mount, tabletop or front panel models. All three feature our 20 slot S-100 motherboard with 25 amp power supply and are delivered fully assembled and tested with our Series II™ board sets. Any board configuration you choose works with any DPS-1 version, allowing you to vary your package offering, or develop on one version and market another

♦ Front Panel model — a powerful development and diagnostic tool for Z-80^systems, which can be used for prototyping, servicing, debugging, and software or hardware development. Use its features to set breakpoints, trigger scopes, single step, slow step and more.

♦ Front Panel less desk top model—a lower cost option for OEM or other turnkey operations which do not require the extra capability of our Front Panel.

♦ Rack Mount version—features a heavy gauge frame designed to fit into standard 19" racks. CVT power supply for brown out immunity is standard.

*ln Calculus, a fundamental statement In the definition of limit; interpreted here to imply: "For your integration problem, Intersystems has a solution.'

t Registered trademark o1 Zilog, Inc.

Your LIMITS?

OPTIONS

TO SOLVE Ym

PROBLEMS.

Board level options...

Intersystems mainframe packages, equipped with Series II boards, are operational in both 8 and 16 bit settings and support extended addressing in both I/O and memory space, recognizing 16 bit I/O addresses and 24 bit memory addresses. Just look at these individual features;

♦ 6 Sl/O — six individually softvv'arecontrollable serial I/O ports with optional interrupts. Each can run RS 232 at up to 19,200 BAUD, as can our Vl/O board.

♦ Vl/O —has two serial ports; two 8-bit parallel output and two 8-bit parallel input ports plus 8 individually controllable command lines and 16 levels of vec-' tored interrupts.

♦ FDCII—can DMA up to a full track into 16 Megabytes of memory. Optionally generates interrupts and handles up to four 8" floppies.

♦ MPU-8000-available with the nonsegmented Z-8002^, which directly addresses 64K, or the segmented Z-8001^, which can directly address 8 Megabytes.

Extended systems options...

Interfacing disk drives is not a trivial matter, so when your objectives and resources dictate you spend your energy elsewhere, use our resources to perform the service for you. We can add our disk drive package to any Z-80 or Z-8000 configuration we provide ... again, fully assembled and tested and covered under one warranty.

Or our complete

Pascal Development System.

We use it for our own hardware and software development. It includes either table-top mainframe, two 8" floppy disks, 128K RAM, CP/M*, and Intersystems Pascal/Z™ compiler and Cache BIOS™.

THIS SYSTEM IS FAST! Why? Because our ultra-fast Cache BIOS automatically buffers whole tracks, eliminating most disk accesses. This delivers up to three times the throughput of any other floppy-based system we know and is equal to many small hard disk systems.

The system is versatile, too. SET program allows you to change many BIOS parameters and specify control characters to enable special features such as diagnostic output to trace program execution. It can also provide remote I/O to link your system to almost any other computer, ^ , , . large or small.

And it's reliable. The Cache BIOS System runs continuous memory tests when idle, and verifies with a Read after Write and Read after Read.

And the system also includes our Pascal/Z, a true native compiler producing ROMable and Re-entrant code. It features a minimum of extensions chosen for the development of your scientific and business applications. And it's compatible with our native code Pascal for Z-8000, providing a graceful upward path to 16 bit applications. So what you write now is right later.

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Editorial

Technological Measures

The ultimate answer is to make it so difficult and costly for the pirate to make copies that the problem goes away. A good first step is to put teeth into software protection laws. The revised copyright act of 1976 had a major impact on phonograph record pirates because of the much more stringent penalties for convicted offenders. You may have noticed the®sign on commercial records and tapes: it's an indication that they're protected by the new law. (For further legal background, including information on the latest Supreme Court decisions, see "Washington Tackles the Software Problem," page 128, and "Legal Protection for Computer Hardware and Software," page 140.)

We come next to the most intriguing weapon in our arsenal: hardware 'locks" on the software. The concept of the I.D. ROM is a recent development now being used, among other places, in conjunction with a program called RCS/Micro Modeller, developed in England by Intelligence (UK) Limited. The program allows a person to use an Apple II computer to create financial planning models and high-resolution color displays featuring pie charts, histograms, and so on. A novel feature of the program is its "electronic slide show" capability: a hand-held control, similar to a slide projector control, plugs into one of the paddle ports of the Apple and allows the user to cycle through an electronic "slide show" on the video screen. Built into the control is a special ROM containing an identification number that is duplicated on the program floppy disk. The program periodically checks for the presence of the I.D. ROM. If it's not found, the program crashes.

This technique puts one more stumbling block in the way of the pirate, and it does not add appreciably to the total cost of the software (the I.D. ROM costs about $20). Alas, there are some experts in Europe who have cracked the code of another I.D. ROM used in conjunction with a program called Wordcraft, which is being distributed by Commodore in England. So the technique, while making it much more difficult to copy software, is not the ultimate answer. Still, 1 welcome this type of innovative approach to a mind-boggling problem. Readers interested in further information about the RCS/Micro Modeller program (not yet available in the United States) should contact David Low, ACT (Microsoft) Ltd, 5/6 Vicarage Rd, Edgbaston, Birmingham B15 3ES England.

Two of the most promising solutions to the software protection problem come from West Coast inventor Marc Kaufman. He has filed a patent for an "executeonly ROM," a new type of read-oiUy memory which produces a sequence of executable code in the normal manner, but prohibits the user from randomly accessing memory addresses. As Kaufman explains, the user begins execution of the program at a known address. A "secret" executive routine, built into the ROM, contains a table of the legal next steps for every given step in the program. Only those steps listed in the table can be accessed by the

user. For example, if the program contains a branch to one of two places, only those two places can be examined by the programmer at that time. If a program contains enough branches, it would take an inordinate amount of time for the user to run through every permutation of the program to get a complete listing of the code, even if a computer did the searching. Kaufman is presently working with both hardware vendors and users to develop the idea. An unreadable EPROM is also in the works, enabling the do-it-yourselfer to create secure programs.

Kaufman's second idea is to add a "black box" to a personal computer. Every piece of software would come with a magnetic key (or other type of hard-to-duplicate key) that plugs into the black box and contains a coded I.D. number that matches the I.D. number on the floppy disk. The program resides on the disk in encrypted form. In order to decode the program, the key must be plugged into the box. With this scheme, the user can make as many backup copies as desired, but only one of them can be used at a time. The drawback to such a system is the need for the black box. But if the idea catches on, the price would probably come down. Interested readers can contact Marc Kaufman at Kaufman Research, 14100 Donelson PI, Los Altos Hills CA 94022.

Stopping the pirate is vital. Piracy has reached near epidemic levels in Europe, where it is not uncommon for an entire computer club numbering in the hundreds to line up their computers and make hundreds of copies of programs from United States manufacturers for the use of the entire club I Then there is the phenomenon of the "software library." Some of them are legitimate, but all too many cavalierly offer copies of programs to their members at a fraction of the retail cost.

Illegitimate copies of programs threaten the fabric of personal computing. The software innovators in our field must be compensated fairly for their work, or we will no longer see the high-quality programs that currendy grace the marketplace.

I welcome comments from readers about this allimportant issue, and would like to begin a dialog featuring your comments. Please send your thoughts to: Software Protection, c/o BYTE Publications Inc, POB 372, Hancock NH 03449. ■

Articles Policy

BYTE is continually seeking quality manuscripts written by individuals who are applying personal computer systems, designing such systems, or who have knowledge which will prove useful to our readers. For a more formal description of procedures and requirements, potential authors should send a large (9 by 12 inch, 30.5 by 22.8 cm), self-addressed envelope, with 28 cents US postage affixed, to BYTE Author's Guide, 70 Main St, Peterborough IMH 03458.

Articles which are accepted are purchased with a rate of up to S50 per magazine page, based on technical quality and suitability for BYTE's readership. Each month, the authors of the two leading articles in the r^der poll (BYTE's Ongoing Monitor Box or "BOMB") are presented with bonus checks of SIOO and S50. Unsolicited materials should be accompanied by full name and address, as well as return postage.

10 May 1981 © BYTE Publiutions Inc

Circle 385 on inquiry card.

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Parallel (APIO™). For parallel interfaces, our APIO offers two 8-bit bidirectional ports. We also include additional interrupt and handshaking lines, plus software control of the interface configuration and data direction. Cables for Centronics and other printers are optional.

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Letters

Educational Dialog

As a junior-high-school teacher with several years of experience, I want to call into question some of the underlying assumptions in Seymour Papert's "New Cultures from New Technologies." (See the September 1980 BYTE, page 230.)

Mr Papert seems to believe that children and child-initiated explorations are inherently good and, conversely, that parents, teachers, schools, and their limits and expectations are inherently bad. Also, he seems to believe that all learning can and should be as swift, natural, accurate, and frustration-free as the learning of spoken language, and that learning by rote or rite is without meaning and is harmful to the child.

To the first supposition, I can only reply that there is a time and place to be child-centered, and a time and place to be goal-directed. To the second supposition, language acquisition has little to do with other types of learning—it is a highly specific capability that is "hard-wired" in

to the brain from birth. Finally, rote and I rite learning are common elements in spontaneous children's play, to say nothing of adult culture.

Piagetian learning is at best an unfortunate choice of words on Mr Papert's part, because Piaget did not focus on learning at all. He studied the cognitive processes in children that depended on maturation, not learning, and were indeed highly resistant to any learning experiences he was able to devise. His great contribution to education was to point out that there are thresholds and there are ceilings to what an immature mind can learn. The insight-oriented "new math" failed in public education for this reason: its proponents were asking grade-school children to perform abstract reasoning, which Piaget terms formal operations, before they were ready to do so.

Anyone wishing to teach young children to program computers, regardless of formal language instruction, had better remember a few things: Piagetian formal operations begin in adolescence. It is not

safe to assume that a preadolescent is doing what you think he is doing, in the way you think he is doing it, or for the reason you think he is doing it. You ignore Piaget at your own peril.

In summation, no single development is going to revolutionize education, because it is a "soft" field—too many factors are operating already. The computer probably will be the biggest thing ever to hit the field, but not for the reasons Papert thinks.

Charles Meckel 1624 Hillcresl Glendale CA 91202

Seymour Papert Replies:

/ agree with Mr Meckel that one ignores Piaget at one's peril. I have tried not to ignore him. I spent about 5 years working in his center for Genetic Epistemology in Geneva, Switzerland. In my hook Mindstorms: Children, Computers and Powerful Ideas, / argue that our work on Logo is in the spirit of Piaget's theory even if it seems to contradict some of his empirical findings,

/ grant that children in many countries have been found to follow a fixed pattern of intellectual development. I grant that psychologists have failed when they tried to change this pattern of development by exposing children to a few hours of special treatment under laboratory conditions. But, I argue in Mindstorms that the penetration of computers into the lives of children (indeed into the whole culture) will exert a much more massive influence on intellectual development than any experiments in the past. I suggest that it is possible that these more massive influences will have correspondingly massive effects. / don't see how any of Piaget's experiments could conceivably be held to exclude this possibility.

In addition to these general issues, there is one specific point of Piagetian interpretation on which I must express disagreement with Mr Meckel. Piaget certainly did not believe, as Mr Meckel asserts, that the acquisition of language "has little to do with" other types of learning or that it is "hard-wired." This sounds more like Noam Chomsky's position against which Piaget argued with increasing vigor in the last years of his life.

FINALLY, A COMPREHENSIVE SOFTWARE CATALOGUE THAT ISN'T HARD ON YOUR WALLET.

Like you, we were appalled that some software catalogues cost twenty bucks or more. So we decided to do something about it. We've put together our own software catalogue. And we're selling it for a lot less. Less than the price of this magazine, in fact.

It's the new Micro Dimension's Software Catalogue and it contains a full complement of computer programs. Business, educational, games- entertainment and utility. All brands. With descriptions that include systems requirements.

So pick up a copy at your local computer store. After all, a software catalogue shouldn't have to cost as much as the software.

12 May 1981 © BYTE Publications Inc

Circle 243 on inquiry card.

Edison had over 1,800 patents in his name, but you can be just as inventive

with an Apple.

Apple is the company with the brightest ideas in hardware and software and the best support — so you can be as creative with a personal computer system as Edison was with the incandescent bulb.

How Apple grows with you.

With Apple's reliable product family, the possibilities of creating your own system are endless. Have expansion capabilities of 4 or 8 accessory slots with your choice of system.

Expand memory to 64K bytes or I28K bytes. Add an A to D conversion board. Plug into time sharing, news and electronic mail services. Use an IEEE 488 bus to monitor lab instruments. Add 4 or 6 disk drives — the 5'A" 143K bytes, high-speed, low-cost drive that's the most popular on the market.

Apple speaks many languages.

Since more than 100 companies create software for Apple, you'll have the most extensive library in the personal

computer world. Want to write your own programs? Apple is fluent in BASIC, Pascal, FORTRAN, PILOT and 6502 assembly language.

There's even a series of utility programs called the DOS Tool Kit that not only lets you design high-resolution graphic displays, but lets you work wonders with creative animation.

More illuminating experiences in store.

You won't want to miss all the Apple products being introduced at your computer store all the time. Don't let history pass you by Visit your nearest Apple dealer or call 800-538-9696. In California, 800-662-9238. Or write: Apple Computer, 10260 Bandley Drive, Cupertino, CA 95014.

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Letters

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Dual Systems has all the boards it takes to do the job in the toughest factory environments. All are designed to function dependably in the real world of industrial control. All operate with Cromemco, North Star and other S-100 systems. A/D board. 12-bit precision. 32 singleended inputs. Or 16 differential inputs. 25 fis conversion time. Vectored interrupt. $635. Or $725 with 1 to 1000 gain transducer amplifier. Works with our thermocouple compensation board and our 4-20 mA input boards as well. D/A board. I^ur independent channels. 12-bit precision. Input is binary or 2's complement. Compatible with all existing I/O mapped software. $495. Drives our amplifier board which outputs 4-20 mA. CMOS RAM board. On-board battery back-up preserves data a year. 200 ns read/write time. Runs at 4 MHz. 8K bytes $590.16K bytes $990. CMOS clock board. On-board battery bacl<-up keeps clock running a year New LSI chip carries date, hours, minutes and seconds. Read or write directly from I/O port. Vectored interrupt. $250.

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1

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THE NEW RELIABLES

Ada Manual Available

The reference manual for the Ada programming language, July 1980 version, is now available from the Government Printing Office. The supply in the Defense Department's DARPA office (referred to in "BYTELINES," January 1981 BYTE, page 200) is now exhausted. Requests should be sent to:

Superintendent of Documents US Government Printing Office Washington DC 20402

Order number: 008-000-00354-8 Cost: $5.50 per copy.

I learned this when I requested information from DARPA about the manual.

Mike Robinson Rt 4, Box 70 Ringgold GA 30736

Hard Disk to Buy

I was quite amused to read that manufacturers are unable to understand why small hard disks aren't selling as expected. (See "Winchester 8-inch Drives Off to Slow Start," December 1980 "BYTELINES," page 214.) Perhaps the reason could be the typical $5000 to $8000 price tag—more than a little difficult to justify to your wife, mother, girlfriend....

Besides the normal budgetary problems, I have no way to interface a hard disk to my Heath H-8 computer, either in hardware or software. Another problem is that most hard disks are not removable. Imagine the added utility of a drive using an 8- or 14-inch cartridge, holding about 20 megabytes, costing $2000, and removable (so you can take it to your friend's house). Come to think of it, that's a good description of a DEC (Digital Equipment Corporation) RK05 cartridge disk-pack drive.

John F Priebe 4804 Mt Airy Rd Sylvania OH 43560

Plot: North by Northwest

I found John Beetem's article "Vector Graphics for Raster Displays" enjoyable. (See the October 1980 BYTE, page 286.) But, when I read R H Rae's letter, I had to respond. (See "Intercepting Raster," January 1981 BYTE, page 14.) Beetem's vector-generator routine works beautiful

ly for its intended purpose. But Rae's alternative suggests that there are those who could profit from a little "compuservation" (running faster on fewer bytes).

The routine I use to drive my Houston Instrument Hiplot plotter is a modification of the one that appears in Hiplot brochures (it is actually Algorithm 162 by Fred G Stockton; Collected Algorithms from ACM, 1963). I offer it in a minimal BASIC as Houston Instrument did. It assumes that the PRINT statement goes to the Hiplot, which ignores all characters except "p" thru "w," and "y" and "z." "p" means move the pen one increment (0.005 inch) north, "q" northeast, "r" east, and so on to "w" meaning northwest.

10 A$="rqvwpsvupqpwtstu" 20 INPUT X,Y

30 PRINT"z":REM PEN DOWN

COMMAND 40 GOSUB 100

50 PRINT"y":REM PEN UP

COMMAND 60 GOTO 20

70 REM *** VECTOR GENERATOR

SUBROUTINE *** 80 REM THIS SUBROUTINE DRAWS

THE BEST STRAIGHT 90 REM LINE FOR A COORDINATE

CHANGE OF (X) AND (Y) 100 1 = 1: IFX<0THENX=-X: 1=3 110 IF Y< 0 THEN Y= -Y: 1=1-1-4 120 IF X<Y THEN T=X: X=Y: Y=T:

1 = 1-1-8 130 E=-X/2: C=0 140 IF C > X - .5 THEN RETURN 150 E = E4-Y: IF E>0 THEN E=E-X: PRINT MID$(A$,I+1,1): GOTO 170 160 PRINT MID$(A$,I,1) 170 C=C-I-1: GOTO 140

This routine is marvelous; no multiplications and only an avoidable right shift in line 130 (the entire routine, including the array and double-predsion variable storage, requires less than 130 bytes of 8080 code).

The byte miser in me demanded that I understand this routine. When I found its logic as simple as the routine, I couldn't resist configuring it for screen graphics and animation, turning a printer into a plotter, and tackling the awesome task of massaging my plotter into a super printer.

If it is not too late, Mr Rae, you might consider using Stockton's algorithm for your commercial graphics product.

William A McWorter Jr Mathematics Department Ohio State University Columbus OH 43210

14 May 1981 © BYTE Publications Inc

Circle 202 on Inquiry card.

SUPERBRAIN QD

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SUPERBR4IN

the two top micfocomputer contenders

When you decide to buy a microcomputer system, it usually gets down to one model versus another Will it be the SuperBrain from Intertec... or one of those other models from Intertec's competitors? Well, there's really not much of a choice in the price/performance competition. The SuperBrain wins hands down! And it's a pretty tough contender If reliability, factory support and nationwide service are important to you. So what do you do?Choose our SuperBrain just because you know it's best? Or keep waiting for someone to announce something better?

WAIT NO LONGER...

It wasn't enough that our SuperBrain had such standard features as twin double-density disk drives with nearly 350,000 bytes of disk storage. A full 64K ot dynamic RAM. A CP/M* Disk Operating System which assures compatibility to literally hundreds of application packages. A crisp, 12" nonglare screen with a full 24 line by 80 column display A full-featured ASCII keyboard with a separate keypad and individual cursor control keys. Twin RS232 serial ports for fast and easy connection to a modem or a printer Plus, dual Z80 processors which operate at 4 megahertz to insure lightningfast program execution. No, it wasn't enough. So we changed it. We made it even better!

ANNOUNCING SUPERBRAIN OD...

Our new OD model boasts all the features of our phenomenally popular SuperBrain with the addition of double-sided disk drives. So, for only a modest increase in price, you can order your next SuperBrain with more than twice the disk storage. But, best of all, you can field upgrade the disk capacity of either model to a whopping 10 megabytes! Now how's that for a choice?

HOW DID WE DO IT?

The secret of SuperBrain QD's incredible disk storage lies within our new double-density, doublesided disk drives. Nearly 750,000 bytes of data can be formatted on two specially designed 514" drives. More than enough to tackle almost any serious small business application. Plus, SuperBrain QD's 64K of dynamic RAM will handle even your most complicated programming tasks.

Of course, if you really need megabytes instead of kilobytes, just add our 10 megabyte CompuStar™ Disk Storage System. It connects in seconds and gives you the capability to expand your system into a powerful multi-user network with up to 255 CompuStar terminals. You can add users one at a time as you need them. So no matter how much your needs expand, your original investment in computer hardware is always protected.

BUT IS IT RELIABLE?

Our best salesmen are our present customers. Not only have SuperBrain and OD users been impressed with the inherent reliability of the systems, they tell us that no other microcomputers available offer such a unique modular design concept. Just about the only service tool required is a common screwdriver But of course if you'd rather let us do the service, our total commitment to product and customer support, with service outlets in most major cities, will guarantee your satisfaction for many years to come.

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Call or write us today for more information on our full line of microcomputer systems. Ask for our "SuperBrain Buyer's Guide" and read why so many customers like yourself have made the SuperBrain and the SuperBrain QD their top two choices for performance, value and reliability.

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BYTE'S BOMBworks

My December 1980 BYTE did not include the usual Reader's Service and BOMB cards, so here are my December BOMB votes.

My vote for the best article of the year is Grady Booch's Micrograph series. (See "Micrograph, Part 1: Developing an Instruction Set for a Raster-Scan Display," November 1980 BYTE, page 64; "Part 2: Video-Display Processor," December 1980 BYTE, page 120; and "Part 3: Software and Operation," January 1981 BYTE, page 238.) I eagerly awaited my January BYTE for the concluding part.

Mr Booch's design was good, but the hardware could have been upgraded for better performance. According to my calculations for the color chip, the Z80 microprocessor is active only 12% of the time with the hardware configuration shown. The Motorola spec sheets give a better hardware implementation: isolate the display memory from the processor memory when the display circuitry is accessing display memory. Such an approach would allow fuller utilization of the Z80, as well as remove response-time problems from the interface to the host computer (ie: lost time when the Z80 is locked out by the display). All in all, Mr Booch's articles were excellenti

1 had a different opinion of the competing serials on graphics. Alan Grogono's "Graphic Color Slides" articles gave no insight into the more general problem of graphics. (See the November and December 1980 BYTEs, pages 126 and 96, respectively.) Allen Watson's "A Simplified Theory of Video Graphics" presented little if any new information on either hardware or software. (See the November and December 1980 BYTEs, pages 180 and 142, respectively.) He might as well have referred to some of the many articles and books on the television signals (eg: the TV Typewriter Cookbook or some such). I rate both of these articles poor.

On a more positive note, I enjoyed all of the game reviews and would like to see more for other software packages. These, however, would rate only a good, with the exceptions of "On the Road to Adventure"; "Odyssey: The Compleat Apventure"; and "Zork and the Future of Computerized Fantasy Simulations." I rate all of these excellent. (See the December 1980 BYTE, pages 158, 90, and 172, respectively.) I'd also place Steve Ciarcia's "Computerized Testing" in that category. (See December 1980 BYTE, page 44.)

16 May 1981 © BYTE Publications Ire

Circle 424 on inquiry card.

Circle 420 on inquiry card.

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What can you honestly expect from an interactive data terminal that costs only

$369?*

Well, to begin with, color graphics.

RCA's VP-3301 has unique color-locking circuitry that gives you sharp, jitter-free color graphics and rainbow-free characters.

Plus much more: Microprocessor control. Resident and programmable character set. Reverse video. State-of-the-art LSI video control. 20 and 40 character formats. RS232C and 20 mA current loop. Six baud rates. Eight data formats. ASCII encoding. Light-touch flexible-membrane key switches for reliability and long life. CMOS circuitry and a spill-proof, dustproof keyboard for hostile environments.

The VP-3301 can be used with a 525-line color or monochrome monitor or a standard TV set through an RF modulator." It serves a wide variety of Industrial, educational, business and individual applications including communication with time sharing and data base networks such as those provided by Dow Jones News/Retrieval Service, CompuServe and Source.

All this—for the low price of $369. And it's made by RCA. So get the whole story about the surprising VP-3301 today. Write RCA Microcomputer Marketing, New Holland Avenue, Lancaster, PA 17604. Order toll-free: 800-233-0094.

"Model VP-3303 with bullt-ln RF modulator-$389.

"Suggested user price. Monitor and modem not inciuded.

Circle 350 on inquiry card.

I want to compliment BYTE's Production Director, Nancy Estle, on the layout of BYTE. BYTE articles generally manage to stay in one piece, rather than starting in the front and continuing piecemeal throughout the remainder of the magazine. I would like to see even more segregation between articles and advertising, however. I do not object to the ads, in fact I conscientiously read through them, hoping that I won't miss any new developments. But having to wade through the ads to find article continuations is annoying.

Arthur Throckmorton 5657 S Oak St Littleton CO 80127

The CBT Is Dead: Long Live the CBT

In regard to Mr James R Boatright's letter in the December 1980 BYTE, the reported demise of the CBT is somewhat exaggerated. (See "The End of the CBT," page 300.) The CBT-IOOID DAA (dataaccess arrangement), though no longer available from Bell, is currently manufactured by Precision Components, Elgin, and Terminal Systems, etc. It is available from many distributors who are typically listed in the yellow pages under 'Telephone Equipment & Systems." The CBT is used extensively by manufacturers in the medical-data field.

Please be advised, Mr Boatright, you need not discard your equipment requiring use of CBT, CBS, or other types of DAA.

Carl E Osborne Jr

President O & J Electronics Inc 4027 Knight Arnold Rd, Suite 105 Memphis TN 38118

More on HP-41C

Congratulations to BYTE and to Bruce D Carbrey for the excellent article on the HP-41C "calcuputer." (See "A Pocket Computer? Sizing up the HP-41C," December 1980 BYTE, page 244.) With a few enhancements, I used the "CODEBREAKER" demonstration-game program over the holidays with my grandchildren. It is a fine example of the capability of the HP-41C.

Circle 274 on inquiry card. >

Mountain Computer put it all together for you.

The CPS MultiFunction Card

Three cards in one! The Mountain Computer CPS MultiFunction Card provides all the capabilities of a serial interface, parallel output interface and real-time clock/calendar—all on one card—occupying only one slot in your Apple II®. Serial and Parallel output may be used simultaneously from CPS. CPS is configured from a set-up program on diskette which sets the parameters (such as baud rate, etc.) for all functions contained on the card and is stored in CMOS RAM on the card. Once you have configured your card, you need never set it up again. You may also change parameters from the keyboard with control commands. All function set-ups stored on-board are battery powered for up to two years. "Phantom slot" capability permits assigning each of the functions of CPS to different slots in your Apple without the card actually being in those slots! For example, insert CPS in slot #4 and set it up so that is simulates a parallel interface in slot #1 and a clock in slot #7 and leave the serial port assigned to slot #4. CPS's on-board intelligence lets it function in a wide variety of configurations, thereby providing software compatibility with most existing programs. "We've put it all together for you"—for these reasons and many more! Drop by your Apple dealer and see for yourself how our CPS MultiFunction Card can expand the capabilities of your Apple and

save you a great deal of money as well!

Calendar/Clock j |

• One second to 99 years ' t

• Battery backed-up (2 years)

• Two AA standard alkaline batteries for back-up (provided!

• Compatible with MCI Apple Clock'" time access programs

t

Mil

Parallel Output

• Features auto-line feed, Apple tabbing, line length, delay after carriage return, lower to upper case conversion

• Centronics standard— reconfigurable to other standards Status bit handshaking

U

Serial Interface

• Features auto-line feed, transparent terminal mode, Apple tabbing, line length, delay after carriage return, local echo of output characters, simultaneous serial/parallel output, lower to

4Si Mountain Computer

INCORPORATED

300 El Pueblo Scotts Valley, CA 95066 1408) 438-6650 TWX: 910 598-4504

upper case conversion, discarding of extraneous LFs from serial input Uses the powerful 2651 serial PCI chip

16 selectable internal baud rates— 50 to 19.2Kbaud

Half/Full duplex terminal operation I/O interface conforms to RS-232C Asynchronous/Synchronous operation

xp:

'Apple Clock was the trademark of Mountain Computer Inc.

"Apple and Apple II are registered trademarks of Apple Computer Inc.

Lattors ■

But just as any program or product can be improved, so can any article. It is most unfortunate that Mr Carbrey failed to mention two important aspects of the HP41C:

1. The HP-41C continues the use of RPN (reverse Polish notation) logic. Since my first experience with RPN in the 1960s on a Friden CRT desk-top calculator (it used RPN well before Hewlett-Packard), there has been no question that RPN is the only way to go. Not just because it may use less keystrokes, but because its logic is unambiguous, straightforward, and simple to remember. This is a most important attribute of the HP-41CI

2. Even more important, Mr Carbrey failed to mention that all Hewlett-Packard programmable calculators, including the HP-41C, are supported by an active, independent user's organization known as the PPC—Personal Programmers Club. (Formerly known as the HP-65 User's Group.) The PPC has no connection with Hewlett-Packard or its Users Library. A periodic publication, the PPC Calculator Journal, is available to members only. Club members have discovered that many things can be done with the HP-41C and

its predecessors. Although some of these capabilities are not "supported" by Hewlett-Packard, their use can greatly improve almost any program. The club is currently designing a custom ROM (readonly memory) to make these features available to its members.

Anyone seriously using the HP-41C should join the PPC. To get further information, send a 9- by 12-inch stamped, self-addressed envelope with 2 ounces postage to Richard J Nelson, Editor/Publisher PPC Calculator Journal, 2541 W Camden PI, Santa Ana CA 92704. You will receive a sample issue of the Journal and further membership information.

B F Wheeler 22 Wilkins Ave Haddonfidd NI08033

Chessmate

In the December 1980 BYTE, John Martellaro presented a review of the Sargon II chess-playing program. (See "Sargon II, An Improved Chess-Playing Program for the Apple II," page 114.) He

states that it is the first chess program he has seen that sets a trap. He also says that it is the strongest chess program money can buy—dedicated chess-playing devices included. Does this include the Chess Challenger 7 by Fidelity Electronics?

My Chess Challenger 7 on level 7 (tournament level) played exactly the same game as Sargon II, including the trap, through step 12. At step 12, Sargon played Nc3-d5 (N/B3-Q5); Chess Challenger 7 played Qd2-dl (,Q-Ql). My response was Qf6-g6 (Q-KN3), at which point Chess Challenger 7 conceded the game.

I would like to see an entire issue of BYTE devoted to this kind of competition between computers. Does BYTE have such an issue planned?

Tom Disque

Rt 7, Waldrap Dr

Mayfield KY 42066

No such issue is planned, but we will continue to publish reviews of chess programs and playing machines as they come in to us (hint). (See "The Newest Sargon: 2.5" in the January 1981 BYTE, page 208.)

Letters continued on page 268

TIP'S CaU A.E.I.

VlVs customarily need tx)p qiial Itj' and serx'lce within Htringent budgetarj' limits. Islaturally, they call A.E.I.

..For softxvare, flrmware, or hardware; For custom systems assistance, connectors, interface boards and senice; For peripherals, Including printers, CRT's, disc drives, or mixlems; For as little as one part such as a cable or connector, or as much as an entire national computer complex for a nuiltl-branch coniiiany.

Item: A.E.I, tests Wrtually everj'* item sold, before shipping.

Item: A.E.I, initializes even- piece of software, and mEikcs a copy. If you have a problem, A.E.I. can check to locate the problem b>' using the In-house duplicate, Ha\ing you time.

Ifemi A£.I. has In-house expertise on ever\' Item offered.

Item: A.E.I, prices are competitive \\1th the lowest, no-scr\1ce, no in-honsc expertise dealer.

40% OF ALL A.EJ. SALES ARE TO PUBLIC AND SEMI

puBuc iNSTrnmoNS.

Ai«u-tlal list** ofA.E.I.customers whopurchascdduringtlic lust quarter of 1980 Includes: lJnlverslt>' of Nebraska, l^nivcrsity of Virginia, I'.S. Dept. of Interior, Universltv- of Kcntiick)-, I'nlversltj' of California, Massachusetts InsUtutc of Technology', U.S. Air Force, Naval Air Development Center, Brown L'niversitj-, I'niversit>' of Oregon, University of Utah, Ohio State I'nivcrsity, l'ni\crsity of Southern California, California State Dept. of Water Resources, University of Michigan, and Princeton I'niversto.

In the private sector, an equal niunbcr of major national organisations purchased during the same period.

ItMi eu mOI A.B.L toot

*Wlth our nunnal faHt Hhlpplng, we have time to test; cxiHrdlled Hhlpmcnt muv prceliidc teHting.

**AJ:.I. docs not wldh to imply that any t>rtilcHC nncoi^gonlKatloiwcndoiKC AS.1.. merely thut A.E.I. iH proud to liavc them an aitttomcni.

Automated Equipment, Inc. 18430 Ward Street, Fountain Valley, California 98708 (714) 964-7514 (Outside ofCalifomla(800)854-7635)

20 May 1981 © BYTE Publications Inc

Circle 38 on Inquiry card.

Here's the system builder's solution for successful computers and applications. Push in the CCS component. Push in the operating software. And push on with your application. CCS systems and components are designed to go together quickly, and to keep running reliably, with a proven return rate of less than 1%.

And you get performance. The systems deliver hardware vectored interrupts and the capability to interleave DMA data transfers with rates as high as two megabytes per second, plus bank select memory of up to 512K bytes. This 8-bit system provides single user, multiuser, and multitasking capability with ample speed to prevent operator waiting or loss of incoming real-time data.

The systems are available with CP/M or MP/M operating systems. For real-time or multiuser applications, the CCS OASIS real-time multitasking operating system supports re-entrant programs and relocatable code modules, with

circle 58 on inquiry card.

IO Please have a sales representative call me.

IO Please send more information on CCS Systems and Expansion I Modules.

Name

I Company

I Address

[ Cily/State/Zip

I Phone:( )

eCalifornia Computer Systems 250 Caribbean Drive Sunnyvale, CA 94086 _ (408)734-5811

facilities for task-to-task communication, file protection, time-of-day bookkeeping, spooling, task overlay, dynamic memory management, ISAM file structures and deviceindependent I/O. CCS OASIS includes debug, text editing, linkage, and file sort utilities; the system supports a host of existing languages, applications, and utilities from a range of vendors.

Powerful computer systems you can configure to your demanding requirements quickly, and with confidence. Choose from a variety of systems. Expand with CCS boardlevel modules for memory, disk control, high-speed arithmetic, and I/O, plus subsystems for floppy and hard disk storage.

If you sell, install, or use computer systems, you should know more about the CCS product line. We've got a lot more to tell. Tear out and return the coupon for more information. Or call.

CP/M and MP/M are trademarl<s of Digital Research. OASIS is a trademari< of Phase One Systems.

Hardware Review

The Epson MX-80 and MX-70 Printers

Kevin Cohan, Technical Editor

Small system users soon realize that effective programming is difficult without hard copy upon which to make notes, corrections, and general scribblings. However, realization often turns to dismay when the "professional" quality printer carries a price tag larger than that of an otherwise complete popular disk-based microcomputer system. In the past, inexpensive printers (when available) have been slow, unreliable, inconvenient (eg: many require expensive thermal or electrostatic paper), and generally lacking in desirable features. Those users with less than $1000 to spend have been faced with a choice of such a printer or a refurbished IBM Selectric or Teletype ASR33.

Epson Inc has aimed its two new low-priced dot-matrix printers, the MX-80 and the MX-70, squarely at this under-$1000 market (see photo 1). Both have features normally found only in professional printers that are priced accordingly. (Active in the computer printer business in Japan for over fifteen years, Epson has also supplied print heads and mechanisms for such wellknown printer manufacturers as Anadex.)

Photo 1: The Epson MX-70 and MX-80 printers. The MX-70 (left) is a prototype of the final version which has a tan rather than a cream body.

The MX-80

The more expensive MX-80 printer has so many features that a complete learner's manual accompanies the instruction manual. This manual (written by David A Lien and published for Epson by Compusoft) guides the user through basic setup procedures and also describes the less obvious capabilities of the MX-80: it can do much more than provide hard-copy listings I

Measuring 37.4 cm wide by 30.5 cm deep by 10.7 cm high (14'/io by 12 by '^% inches), the MX-80 is not much larger in size than a stack of five or six issues of BYTE. It has a 9-wire print head that prints 96 ASCII (American Standard Code for Information Interchange) characters with lowercase descenders and 64 graphics characters on a 9 by 9 dot matrix, as shown in listing 1. The print head has an estimated life of over 50,000,000 characters, and it can be easily replaced. Print speed is 80 cps (characters per second) bidirectionally, and a long-life print ribbon is contained in an easily removable cartridge.

External features (shown in photo 2) include a metal paper-guide rack, manual paper-advance knob, power switch, Centronics-type 36-pin cable connector, three control pushbuttons, and four green indicator LEDs (light-emitting diodes). In addition, the MX-80 has a tractor-feed paper mechanism and can use three-ply paper (original and two carbon copies). The On-Line pushbutton toggles the printer between on- and off-line modes. The FF (form feed) and LF (line feed) pushbuttons, functional only when the printer is off-line, advance the paper by one form (ie: page length) and one line, respectively. The distance that the paper advances may be changed under software control.

The four LEDs indicate Power, Printer Ready, No Paper, and On-Line. A software-controllable buzzer is located inside the printer case and is activated by a reed switch on the paper guide when the printer runs out of paper. A self-test mode may be activated by turning the printer on while depressing the LF pushbutton; in this mode, all characters provided by internal software are

22 May 1981 © BYTE Publications Inc

Circle 260 on inquiry card.

AN EVEN BETTER IDEA.

Memory — you never seem to have quite enough of it.

But if you're one of the thousands of Apple owners using the SoftCard, there's an economical new way to expand your memory dramatically

16K ON A PLUG-IN CARD.

Microsoft's new RAMCard simply plugs into your Apple 11," and adds 16k bytes of dependable, buffered read/write storage.

Together with the SoftCard, the RAMCard gives you a 56k CP/M"" system that's big enough to take on all kinds of chores that would never fit before (until now, the only way to get this much memory was to have an Apple Language Card installed)

GREAT SOFTWARE: YOURS, OURS, OR THEIRS.

With the RAMCard and SoftCard, you can tackle large scale business and scientific computing with our COBOL and FORTRAN languages. Or greatly increase the capability of CP/M

applications like the Peachtree Software accounting systems. VisiCalc™ and other Apple software packages can take advantage of RAMCard too.

And RAMCard gives you the extra capacity to develop advanced programs of your own, using the SoftCard and CP/M. Even with the RAMCard in place, you can still access your ROM BASIC and monitor routines.

JOIN THE SOFTCARD FAMILY.

The RAMCard is just the latest addition to the SoftCard family — a comprehensive system of hardware and software that can make your Apple more versatile and powerful than you ever imagined.

Your Microsoft dealer has all the exciting details. Visit him soon, and discover a great idea that keeps getting better.

Microsoft Consumer Products, 400108th Ave. N.E., Suite 200, Bellevue, WA 98004. (206)454-1315.

^Ml. i'il.it.'li.iii.--(ffc*'i'M" ■■ A, i , , I .1. M-.u- ..I. ' .■«,!

' -t., .'llll-*.fin|.-i!«»i-.tlM>I."....' "t, ^ I' V I 1 .1

|.t.|l Hi>MM>< '•lliHI* V-j.l :IH ■: I f.l.l*''.!'" . • >• ■■'■1. i-'^ A.I ■ il.

/•GRpSOfT

Photo 2: Control panels for the Epson MX-70 and MX-80 printers. Photo 2a shows the FEED (paper feed) button and the green Power LED (light-emitting diode) on the MX-70. Photo 2b shows the control panel of the MX-80, which has Power, Ready, No Paper, and On-Line LEDs, and On-Line, FF (form feed), and IF (line feed) buttons.

__At a Glance. Name

Epson MX-80

Use

Dot-matrix impact printer

Manufacturer

Epson America Inc 23844 Hawthorne Blvd Torrence CA 90505 (213) 378-2200

Dimensions

37.4 cm wide by 30.5 cm deep by 10.7 cm high (14%o by 12 by 4y5 inches)

Price

$645

Features

Prints 96 ASCII and 64 graphics characters in a 9 by 9 dot matrix (lowercase letters have descenders); 80 cps bidirectional print speed with end-of-line seeking function (increases average print speed); tractor-feed paper mechanism; prints TRS-80

graphics, Japanese Katakana set, special characters for the US, England, France, and Germany; prints an original and up to two carbon copies; programmable tabs; replaceable print head; and a long-life ribbon cartridge

AddiHonal Hardware

Interface card needed for Apple II

Documentation

MX-80 User's Manual by David A Lien, 22 by 28 cm {&Vi by 11 inches), about 100 pages

Options

TRS-80 cable (about $25); Apple II interface card with cable (about $110); IEEE-488 or serial interface (about $65 each); serial interface with 2 K-byte buffer (about $150); 960 dot-per-line graphics option (about $100)

repeatedly printed out to test the operation of the print head, ribbon guide, and motor mechanisms.

Internally, the MX-80 is a truly intelligent printer that incorporates its own microprocessor: an Intel 8049 singlechip 8-bit processor with 2 K bytes of masked ROM (read-only memory), 128 bytes of programmable memory, and twenty-seven I/O (input/output) lines. This microprocessor coordinates the internal logic and controls the two precision stepper motors. One motor moves the print head, while the other advances the paper. The microprocessor is aware of the position of the print head at any given moment and actively seeks the shortest means of travel to the next print position. This feature, in combination with the bidirectional printing capability, constitutes the logical-seeking function, which increases the effective printing speed and minimizes headtravel time to reduce head wear.

Several options may be selected via two internal DIP (dual in-line pin) switches; these include auto line-feed, a full TRS-80 graphics set or a Japanese Katakana character set, and special characters for the US, England, Germany, and France (see listing 2). This last feature allows the printing of umlauts, accented letters, and other characters that are generally unavailable on personal computer printers.

Under software control, the user may select one of three print densities: 2, 4, or 6.5 characters per centimeter (5, 10, or 16.5 characters per inch), which results in 40, 80, or 132 characters on a line. Line spacing (ie: the distance the paper advances when a line-feed code is transmitted) has a default value of 0.423 cm (% inch), but it may be set from 0.035 cm (Vjz inch) to 3.00 cm [l^i inch) in increments of 0.035 cm (^72 inch)—the distance between two wires on the print head. This presents some interesting possibilities.

The number of lines per form defaults to sixty-six but may be set at any whole number less than that. The user may specify up to sixty-four vertical tabs per form and up to 112 horizontal tabs per line. An emphasized character

24 May 1981 © BYTE Publicatioiu Inc

Circle 158 on Inquiry card.

TRANSFER YOUR DATA

INTO

THE HARDCACHE SUBSYSTEM:

^ 30 Megabytes [Formatted] Winchester Disk Average access time 48 milliseconds

^ Cartridge tape drive provides:

Complete backup in under 10 minutes File save/reload Software distribution

^ S-100 Bus Intelligent Interface Card ________—— DMA or programmed I/O data transfer

Disk throughput optimizer

Bootstrap ROM - switch selectable Time of day clock - battery povuered

^ Compatible with

HARDCACMH

CROMEIN/ICO VECTOR GRAPHICS

IMORTM STAR and Other S-100 based computer systems

4^ installs on any CP/M or MP/M system*

■CP/Mand'MP/M cue fe^lttefedlrodoniarlis otBlgbalSeiaorch

EXECUTIVE SYSTEMS, INC.

15300 Ventura Boulevard Sherman Oaks, California 91403 (213) 990-3457

Listing 1: ASCII character set as printed on the Epson MX-80 (figure la) and the MX-70 (figure lb) low-cost printers. Note the lack of descenders on lowercase letters in the MX-70 example.

la

I "#*"/.&' < ) « + ,- . / 0123456789: ; < = > TfflABCDEFS

H I J K L M N O P e R S T U V W X Y Z C \ .1 • ■ • • _ ' a b c d B -f g h i j k 1 m n o

p q r s t u V w X y 2 -C i }

lb

! "#*;<&'■ < >*+:.-. ^0123456789 : 5 < = >?aABCDEFG

H I J K L M N 0 P O R S T U U W X V Z n 3 _ ' a b c d e f s h i J k 1 m n o

=1 r £ t u '-.J' w >( y z -C ! >

Listing 2: The MX-80 has several user-selectable font options, including graphics characters that are TRS-80 compatible (2a), Japanese Katakana (2b), and special characters for the US, England, France, and Germany (2c).

2a

»" ™ II r » n. Ill», i. Ji Bft, : J" : ji i { r ,/ > 7 r I" i f . 'I \ I < K III '"i II 1 "V h 4 1 1 Z I b L £ iC ^ :k i 1 8 i i i

2b

o J •■ ' 'ii 7 4 X A p 2 a ") - 7 --i r> X ■y^ -n ■■f n- 3 n i> :x. t V ''f f- ''J T b ■) z ^ J I'i fc 7 '1 % •? 5 L :■/■ -e t a 3 5 M Jb I,.' □ '7 :•■ " "

2c

U.S„(Sts # a C \ 3 C I } ENBLANDs £ 3 C \ 3 •£ i >

FRANCE! # ^ " g § & a ^ •• eERMANYs # § A o u a 6 u 13

mode (where each character is overprinted a second time) and a boldface mode (where the paper is advanced 0.0118 cm [1/216 inch] before overprinting) are also available (see listing 3). The printer slows to 40 cps in these special modes.

For a cost of about $650, this is more printer for the money than any other available.

The MX-70

Similar in appearance to the MX-80, but with fewer features, the MX-70 is available for about $200 less (suggested retail price, $449). A 7-wire print head produces characters on a 7 by 5 dot matrix at a rate of 80 cps, but the unit does not offer the bidirectional logical-seeking capabilities of the MX-80. The MX-70 has only one green LED for power indication and only one general paperadvance (line feed that repeats if held down) pushbutton. The MX-70 uses the same self-test mode as the MX-80.

Internal jumpers select one of two character sets and auto-line-feed on or off. Tlie MX-70 may be ordered with

either the Japan/USA or the England/Germany special character set in ROM, The user may software-select 40 or 80 characters per line, or a high-resolution graphics mode where binary bit images are directly printed on a 480 by 7 dot per line matrix (ie: the user can print any combination of dots within this graphics density). Line spacing may be from 0.035 cm to 3.00 cm (y,i inch to l%i inch). The ability to advance the paper by the distance between two wires on the print head, combined with the highresolution graphics mode, gives the user an effective resolution of 480 by 792 dots per standard form. The actual form length may be set from 0.424 cm to 51.2 cm (^4 inch to 20% inch).

If it seems strange that the MX-70 offers bit-map graphics and the MX-80 doesn't, it will be no surprise for you to learn that by the time this article is printed, Epson will be offering a retrofit option on the MX-80. For about $100, this option will give the MX-80 bit-mapped graphics at either 480 or 960 dots per line: the latter density is twice that of the MX-70.

26 May 1981 © BYTE PublicaUoiu Inc

In this age of runaway inflation...

Look what $795 will buy

The ideal input device for the small system user.

Available with optional display. "U.S. Suggested retail price

The HIP AD™ digitizer

Inexpensive input to your computer

The HIPADTM digitizer can be used for both converting graphic information into digital values and as a menu. Utilizing either the stylus or the optionai cursor, the operator can input graphic data into the computer by locating individual points on the digtizers 11" x 11" (28cm x 28cm) active area. In the "stream mode" a continuance of placements of coordinate pairs may be input.

Not a kit, the HIPADTm comes complete with both RS-232C and parallel interfaces and has its ovi/n built-in pow/er source. The origin is completely relocatable so coordinates may be positive or negative for a true reference value and oversized material may be input by simply resetting the origin.

Accurate positional information, free form sketches, even keyboard simulation

All can be entered using the multi-faceted HIPADTM digitizer. Its capabilities and \o\N price make the UL listed HIPADTM a natural selection over keyboard entry, inaccurate joysticks, or expensive approximating light pens. It's perfect for inputting isometric drawings, schematics. X-rays, architectural drawings, business graphs, and many other forms of graphic information, as well as creating your own graphics.

Use it with Apple II™ , TRS-80 Level II ™, RET tm or other

popular computers

The HIPAD'sTm built-in RS-232C and parallel 8 bit interfaces make it all possible. (For Apple II order DT-11A, for TRS-80 or PET order DT-11). Furthermore, you get English or metric scaling, data format (Binary/BCD/ASCII), selectable baud rates, and resolution of either .005" or .01".

For complete information contact Houston instrument, One Houston Square. Austin, Texas 78753. (512)837-2820. For rush iiterature requests, outside Texas cail toii free 1-800-531-5205. For tectinical information asl< for operator #5. In Europe contact Houston Instrument. Rochesterlaan 6, 8240 Gistel, Belgium. Telephone 059/27-74-45.

TM HIPAD is a trademark of Houslori Instrument TRS-80 is a trademark o( Tandy Corporation APPLE is a trademark of Apple Computer Inc PET is a trademark of Commodore Business Machiines, Inc,

Circle 186 for literature

Circle 187 to have representative call

houston instrument

GRAPHICS DIVISION OF

BAUSCHGiLOMB*^

Visit us at NCC-Booth 911

The System 2800 is the next logical step in the continuing line of innovative products from the Systems Group.

Unbeatable S-100 Memory Boards

First was the development of the DMB6400 series of S-100 Memory boards featuring the

innovative Bank Select switching technique. This enables users to software select up to four totally independent memory banks per board.

The 2nd Generation

Then came the 2nd Generation of IEEE S-100 COMPATIBLE Z80 PROCESSORS, FLOPPY DISK CONTROLLERS and SERIAL I/O BOARDS. Each has been designed for single user, multi-user or

network operating systems such as CP/M®, MP/M™, CP/Net™ and OASIS™.

The Next Logical Step ...

We challenged our design team to create an innovative yet competitive system utilizing our existing line of field proven, dependable S-100 boards. The result: a highly reliable, quality built, state of the art microcomputer that gives you the cost/performance edge you need to be a leader in your field.

The System 2800 comes with a choice of operating systems: CP/M with an enhanced CBIOS for single user systems and either MP/M or OASIS for multi-user, multi-tasking systems. MP/M is available with either a standard or

CP/M MP/M and CP/Net are trademarks of Digital Researcti OASIS is a trademarl^ of Pfiase One Systems

enhanced XIOS. The CP/M based System 2800 provides improved diagnostic reporting capability and increased sector sizes of 1024 bytes yielding disk performance throughput increases up to 400% over standard unblocked systems.

The enhanced multi-user, multi-tasking MP/M based System 2800 provides the same advanced features as CP/M. In addition, this interrupt driven implementation can offer performance throughput increases up to 2000% thru extensive disk buffering for applications requiring a large number of disk accesses.

Also available is the OASIS operating system with ISAM files, automatic record locking and multiple-user print spooling.

All operating systems are available in either floppy or hard disk configurations. The disk drive selection includes single or double sided, double density 8-inch floppies with up to 2.52 megabytes of formatted storage per system, expandable to 5.04 megabytes, and an 8-inch 10 megabyte Winchester hard disk.

Cost Effective Reliability

Dealers, OEM's and System Integrators share many common needs. Not the least of these is dependable products. That's why we back our System 2800 with our established reputation for high quality products, superior support, prompt and courteous service, and a one-year warranty.

Take the next logical step. See your nearest computer dealer, or contact us for the complete story on our S-100 family of board products and enhanced systems.

Systems

A Division of MEASUREMENT systems &^ controls

incorporated

1601 Orangewood Ave.

Orange, Calif. USA 92668

(714) 633-4460 TWX/TELEX: 678 401 TAB IRIN

For International Sales Inquiries contact: SIGMA INTERNATIONAL, INC., P.O. Box 1118, Scottsdale, AZ 85252 USA (602) 994-3435 / Telex 165 745 Sigma

See us at booth 5001, NCC show, Chicago, May 4-7, 1981.

Name

high-resolution

Epson MX-70

graphics mode,

replaceable print head.

Use

and long-life ribbon

Dot-matrix impact

cartridge

printer

Additional Hardware

Manufacturer

Interface card needed

See "At a Glance" box

for Apple II

for Epson MX-80

Documentation

Dimensions

iVlj\ /U Libel b iviUriUUl

Same as MX-80

by David A Lien, 22

by 28 cm {8Vi by 11

Price

inches), about 80

$449

pages

Features

Options

Prints 96 ASCII

Choice of either

characters in a 5 by 7

USA/Japan or

dot matrix; 80 cps

England / Germany

pnnt speed; tractor

special character sets

feed paper mechanism;

in ROM; TRS-80 cable

prints an original and

(about $25); Apple II

up to two carbon

interface with cable

copies; includes a

(about $110)

Some things are just naturally right.

tiny-c is a structured programming language designed to allow you to focus attention on tiie problems you want to solve — rather than the language you're using to solve it. With tiny-c you can expand your horizons far beyond the limits of BASIC, tiny-c ONE (interpreter), $100- includes Owner's Manual plus wide choice of media, source code. It's still the best structured programming trainer. Tiny-c TWO (compiler), $250 includes Owner's Manual, CP/M® disk, source code. This version puts UNIX® pleasure into your CP/M.

tiny c associates, P.O. Box 269, Holmdel, NJ 07733 (201) 671-2296

You'll quickly discover tiny-c is naturally right for your language needs.

Listing 3: The MX-80 features five various character modes (figure 3a), several of which may be combined to produce different effects. The MX-70 has only two character modes (figure 3b), but has a high-resolution graphics mode (not shown) as a standard feature.

3a

S r A N D ft R D C hi A A C "I" E B BOLDFACE CHARACTERS DOUBLE STRIKE CHARACTERS COMPRESSED CHflRflCTERS

ji) o i I B< iL., E- w I x:> ■ "r in c if-i c-^ f< c "r ez f'< s

3b

REGULAR CHARACTERS

e: f- m o e: c> c h f=i r: c t e: r: s

New Jersey residents Include 5% sales tax. Visa or Master Charge accepted. Include charge plate number with order, s CP/M Is a trademark ol Digital Research. Inc. " UNIX Is a trademark of Bell Labs. Inc. ^ llny-c is a trademark ol liny c associates.

[Editor's note: I was very pleased with the quality and reliability of both printers, but would like to mention two very small complaints. First, the MX-80 has a piercing alarm tone that sounds for three seconds whenever it receives a "bell" character. This causes some annoyance when the printer is used with an Apple II, which beeps during printing errors and causes the Epson printer to beep. Second, both printers are so quiet when not working (hardly a criticism) and the power-on LED is so small, that it is easy to overlook these indications and leave the printers on overnight....GW]

Interfacing

Both the MX-80 and MX-70 printers communicate through an 8-bit parallel port that is available on a 36-pin Centronics-type cable connector. Some computers require a special interface in order to use the Epson printers, but all necessary interface components are available from Epson Inc. TRS-80 owners may use the standard Radio Shack printer cable, but due to a slight difference in connections, only the official Epson cable allows the separation of the carriage return and line feed characters. This permits the user to underline and overstrike characters, a capability that is not possible with the Radio Shack cable. Apple users will be glad to know that Epson is marketing a special interface card with cable that will plug directly into a peripheral slot in their computer. However, due to a peculiarity of the Apple's video memory, the Apple interface card will not transmit ASCII codes greater than decimal 127, thus preventing use of the MX-80 graphics set. [Computer Comer of New Jersey, 439 Route 23, Pompton Plains NJ 07444, telephone (201) 835-7080, modifies either the Ep

30 May 1981 © BYTE Publications Inc

Circle 411 on inquiry card.

Atari'

lie" software.

A financial VP in Massachusetts is cutting the time it takes to prepare month-end reports from three days to three hours.

A California company is replacing most of its time-share computer service with a personal computer and VisiCalc, saving at least $30,CKX) the first year.

Thousands of other personal computer users are also sold on how VisiCalc is increasing their productivity. Besides saving time and money, they're simplifying their work and getting more information that helps them make better decisions. A typical user reaction comes from a New York dentist:

"VisiCalc has become an integral part of my business''

VisiCalc displays an "electronic worksheet" that automatically calculates nearly any number problem in finance, business management, marketing, sales, engineering and other areas. The huge worksheet is like a blank ledger sheet or matrix. You input problems by typing in titles, headings and your numbers. Where you need calculations, type in simple formulas (+,—, X,^) or insert built-in functions such as net present value and averaging. As quickly as you type it in, VisiCalc calculates and displays the results.

'1 am extremely impressed with VisiCalc's capability, flexibility and orderly presentation of instructions'.'

So writes the director of a New York corporation. He appreciates VisiCalc's powerful recalculation feature. Change any number in your model and instantly all numbers affected by that change are recalculated and new results are displayed. You can ask "What if.. .7^' analyzing

Commodore is a registered trademark of Commodore Business Machines Inc., Atari is a registered Irademarlc of Atari Inc., Apple is a registered trademark of Apple Computer Inc.

Circle 325 on inquiry card.

more alternatives and forecasting more outcomes. It really increases your decision-making batting average!

When you finish, you can print a copy of the worksheet just as it appears on the screen and/or save it on diskette.

"I like VisiCalc's ease of use"

That response comes from a Utah businessman using VisiCalc for production forecasts, financial report ratio analysis and job cost estimating. Ease of use is VisiCalc's best-liked feature. It's designed for a non-programmer, and has an extensive, easyto-understand instruction manual.

Users also like solving a wide variety of problems with VisiCalc . . . and solving them their way. VisiCalc can even justify the cost of a personal computer, according to a New Hampshire financial analyst:

"VisiCalc is paying for itself over and overf'

VisiCalc is available for 32k Commodore PET/CBM, Atari 800 and Apple disk systems. VisiCalc is written by Software Arts, Inc.

See VisiCalc at your Personal Software dealer. For your dealer's name, call Personal Software Inc. at 408-745-7841, or write 1330 Bordeaux Drive, Sunnyvale, CA 94086:

While there, see our other Productivity Series software: Desktop Plan and CCA Data Management System. They're like time on your hands and money in the bank.

See us in Chicago at NCC, booth 881

son or the Apple parallel interface cards to allow access to the graphics characters on the MX-80 printer. The modification is simple—the data-bit-7 line to the printer (the line that controls the highest bit of the 8-bit interface) is isolated from the interface board and connected via a wire to one of the annunciator output bits coming from the Apple II game socket. A POKE statement can then toggle this line, causing the MX-80 to print either normal ASCII characters or Epson graphics....GVJ]

In addition to the standard TRS-80 cable and Apple II board/cable interfaces, which are available for both printers, the MX-80 will also have the following interfaces: IEEE-488, serial, and buffered serial (which includes a 2 K-byte character buffer). Approximate prices are given in the MX-80 "At a Glance" text box.

Conclusions

• The Epson MX-80, at $645, and the MX-70, at $449, both represent an unprecedented level of performance for the price. Although the low price of the MX-70 is particularly attractive, the added features of the MX-80 make it worth the extra $200. The most important features are the intelligent bidirectional printing (which significantly increases the printing speed) and the 9 by 9 dot matrix for letters (which allows true descenders on lowercase letters like "y" and "g" and results in a more readable text).

• Both printers require tractor-feed paper, which limits the user's choices (eg: standard letterhead stationery can't be used), but also assures precise placement of text on a page. And what other low-cost printer prints on ordinary

IMPORTS

COMPUTERS

ADDS

EPSON MX-80

Price Dreokthrough ■ Coll! OkldotoM-aO M17 OkidotoM-82 S617 OWdotoM-83 $919

PAPER TIGERSi

445G $749

460G $1119

CENTROnilCS

737-P $695

AtQri-825 $695

niORTHSTAR

Durned ond tested - bocked by fost wottonty setvice. Find out why out prices. Qvolloblliry ond service make us the *1 source for the #1 s-100 system. Free gomes disc. HRZ II 64K DD $2595

HRZ-II 64K Quod $2995

HRZ II 32K DD $2339 HRZ-II 32K Quod $2689

ALTOS

ATARI

800 W/16K

$744

now MORE FOR LESS

ACS-8000-1 5 tios 208K RAM. 1 Mg. on floppys. 6 seriol and 2 poroiiel ports. Upgtode w/Win. ctiesier hofd-dlsk drives ond tope bock-up. Multi-user Qt singie uset ptices.

ZENITH

The all-in-one compurer thof's backed by your local Zenlih/Heorh service cenrer.

Z89 W/46K 2 SIO's $2149

ACS8000-15

$4795

We parrlclpore In orbltrarlon Jli^ for business and cusromers rhrough the Oerrer Business Dureau of Maricopa County.

/ V

Scottsdole Systems

6730 E.McDowell Rood # 103, Scottsdole, Arizona 65257 |

^^^^ open 8-5 Mon.-Frl.

— (602)941-5856

(We Export) TWX 910-950-0062 (IMEC SCOT)

Tile new leodet! DeiQclioble keyboord. exifO port. 0 function keys, numeric keypod. 24x80. (^S-232, buiit ond bocked by ADDS.

ADDS Viewpoint

$589

TELEVIDEO

912C $729

920C $759

950 $949

TERMINALS

Soroc IQ 120 Soroc IQ 135 Hozeltine 1421 Zenith Z-19 ADM-31

$729 $799 $779 $789 $1095

MORE PRINTERS

HIGH SPEED

Anodex 9500/9501 $1295 DotQ South DS-180 $1395 ■TI810Bosic $1495

LETTER QUALITY-::

Dioblo 630 $2289 NEC 5510 $2689 NEC 5520 $2945

C*Prices include Troctors)

ORDERING

Moll-Order Only

2% cosh discount Included / chorge cords odd 2%. Prices subject to change, product subject to Qvollobliity. Arlzono residents odd 5%. F.O.D. Scottsdole. 0-20% restocking fee for returned merchondlse. Worrontles Included on oil products.

(Users 2 through 16 — multiuser expansion with high performance through distributed processing.)

Look for a single user CF/M® system that expands to multiuser conTigurations economically.

Look for independent 6 MHz Z80B-based User Modules with 64Kof RAM memory, each module with a port to the user terminal capable of handl ing baud rates of up to 38K under program selection. Look for high-speed block data transfers from user modules to the Global Processor for disk storage. That way, CP/M programs run independently for each user. Fast. And each users's station acts just like the fastest standalone system — no delays, no waiting for other users.

Look for a Z80-based Global Processor for disk and tape I/O that transfers data from disk to user modules at the data transfer rate of the peripheral device. And a controller that handles as many as 8

y -AT-*' > ^-'

\ White Computer.

SMD disk drives for up to 528 megabytes of hard disk storage, plus up to four 8" floppies, plus optional streaming tape backup.

And look fora Z80-based General I/O Processor that supports up to eight printers — with 64K bytes of independent buffer memory.

That's part of how you tell if it's a White Computer. There's a lot more. Here's a number and address for more information.

CF/M is a registered trademark of Digital Reseach.

Z80, Z80A, Z80B are registered trademarks oFZIlog Corporation.

White Computer Company A 1876 Industrial Way Redwood City, California 94Q63 A 415 364 7570

Circle 433 on inquiry card.

Computer Generated Graphics Made Simple

Zgrass is an exciting user-oriented language developed for real time interactive graphics.

Zgrass software includes a full screen text editor; point, line, box, ellipse, pattern display and fill graphics routines; full math capabilities; full string manipulation and array capabilities; both interpretive and compiled modes of execution.

• The Datamax* UV-1 Is the only advanced graphics system featuring the Zgrass language.

• Using much of Bally's® commercial video game electronics, the UV-1 shares the same reputation for ruggedness and reliability.

• 64K bytes of memory (16K EPROM, 16K screen RAM, 32K user RAM).

• Z80 microprocessor; floating point math processor; custom video graphics processor; custom input/output processor with 4 A/D converters and 3 channel sound synthesizer.

• 320x202 2 bit/pixel screen; 256 display colors.

• Outputs for RGB and legal, recordable NTSC video.

• Interfaces for graphics tablet, disc drive, joystick controllers, audiotape, RS-232 ports.

• Complete CAI self teaching lesson package. Ideal for education.

EXPLORE THE WORLD OF ZGRASS* GRAPHICS. UV-1 by Datamax." For more information, contact

clatamaxinc.

350 NORTH ERIC DRIVE PAUTINE, ILLINOIS 60067

(312) 991-7410

paper (as opposed to thermal or electrostatic) and produces an original as well as up to two carbon copies by using multiple-ply paper? This ability, due to the fact that both are impact printers, is of particular interest to small business users.

In addition, the print head can be changed (recommended after 50,000,000 characters) by the owner, at a cost of about $30. A quieter print head (5 dB quieter than the standard head during printing) is available for about $40. Like the standard replaceable print head, it can be installed by the user.

• Although the MX-70 and the MX-80 share many features, each has its own graphics option. The MX-70 has bit-mapped graphics that permit control over any dot in a 480 by 7 dot array, one 7-dot column at a time. The MX-80, on the other hand, has the same graphics set as the TRS-80, and an option for bit-map graphics.

• Epson America is beginning to enter the US market and has already begun to train many of its distributors and dealers to act as authorized service centers. The three Epson factory centers, located in Dallas, San Francisco, and Great Neck, New York, also provide service—a major consideration when investing in a unit that is mechanical as well as electronic in nature. (The unusual potential of these machines to do more than simple printing has also led to the founding of an independent Epson Users' Group. For more information, contact Frank Barden, Epson Users' Group, c/o 1017 Trollingwood Ln, Raleigh NC 27604.)

• Both the Epson MX-80 and MX-70 offer a variety of features at a price well below that of any comparable printer on the market. These features, the reputation of Epson, and the thorough engineering that is apparent in the two units, allow me to recommend these printers to any personal computer owner. ■

Circle 115 on inquiry card.

TRS-80* Model I Computer Owners . . .

Double-density storage It's really here!

Here at Percom. And your authorized Percom dealers.

And double-density storage is here in a big way. Because r you can choose from three different levels of mini-disk system! all double-density rated.

And get the storage that precisely meets your applicat needs.

Not to mention the service and quality that's made Percom th industry leader.

Although rated for double-density operation, all levels of Percom drives work equally well in singledensify applications.

You can operate these drives in ordinary singledensity format using TRSDOS* Percom OS-80™ or any other single-density operating system.

Or, you can add a Percom DOUBLER™ to your Tandy Expansion Interface and store data and

!)rograms in either single- or double-density ormat.

Under double-density operation, you can store as much as 350 Kbytes of formatted data — depending on the drive model — on one side of a five-inch minidiskette. That's four times the capacity of standard 35-track Model I minidisks, almost 100 Kbytes more than the capacity of the eight-inch IBM 3740 format!

Available in 1-, 2- and 3-drive configurations in all three model lines, Percom bumed-in, fullytested drives start at only $399.

TFD-40™ Drives

TFD-40 Drives store 180 Kbytes (double-density) or 102 Kbytes (single-density) of formatted data on one side of a 40-track minidiskette. Although economically priced, TFD-40 drives receive the same full Percom quality control measures as TFD-100 and TFD-200 drives.

TFD-100™ Drives

TFD-100 drives are "flippy" drives. You store twice the data per minidiskette by using both sides of the disk. TFD-100 drives store 180 Kbytes (doubledensity) or 102 Kbytes (single-density) per -side. Under double-density operation, you can store a 70page document on one minidiskette.

TFD.200™ Drives

TFD-200 drives store 350 Kbytes (double-density) or 197 Kbytes (single-density) on one side of a minidiskette. By comparison, 3740-formatted eight-inch disks store only 256 Kbytes. Enormous on-line storage capacity in a 5" drive, plus proven Percom reliability. That's what you get in a TFD-200.

The DOUBLER™ — This proprietary adapter for the TRS-80* Model I computer packs approximately twice the data on a disk track.

Depending on the type of drive, you can store up to four times as much data — 350 Kbytes — on one side of a minidiskette as you can store using a Tandy standard Model I computer drive.

Easy to install, the DOUBLER merely plugs into the disk controller chip socket of your Expansion Interface. No rewiring. No trace cutting.

And because the DOUBLER reads, writes and formats either single- or double-density disks, you can continue to run all of your single-density software, then switch to double-density operation at any convenient time.

Included with the PC card adapter is a TRSDOS*compatible double-density disk operating system, called DBLDOS™, plus a CONVERT utility that converts files and programs from single- to double-density or double- to single-density format.

Each DOUBLER also includes an on-card highperformance data separator circuit which ensures reliable disk read operation.

The DOUBLER worl<s with standard 35-, 40-, 77- and 80-track drives rated for double-density operation.

Note. Opening the Expansion Interface to install the DOUBLER may void Tandy's limited 90-day warranty.

Free software patch with drive purchase. This software patcli, called PATCH PAK,™ upgrades TRSDOS* for singledensity operation with improved 40- and 77-tracl< drives.

Quality Percom products are available at authorized dealers. Call toll free 1-800-527-1592 for the address of your nearest dealer or to order directly from Percom. In Canada call 519-824-7041.

TM , , ,^ . Prices and specifications subject to change without notice.

^ trademam or Percom Data Company, mc.

.nark of Tandy Radio Shack Corporation which has no relationship to Percom Data Company.

PERCOM DATA COMPANY. INC.

211 N. KIRBY . GARLAIMD TX ■ 75D42 1214) 272-3421

Circle 322 on Inquiry card.

36 May 1981 © BYTE Publications Inc

Extended Color BASIC for the TRS-80 Color Computer

Stan Miastkowski, Technicid Editor

Inexpensive and easy-to-use color graphics have been the goal of personal computer makers for a number of years. Although graphics have been available, they've been neither inexpensive nor easy to use. Many of the systems currently on the market require the skills of an experienced machine-language programmer in order to generate high-resolution graphics. Some manufacturers have simplified the process; but, for the most part, generating a full-color graphics display is still a tedious exercise.

Radio Shack has released the first

truly easy-to-use and inexpensive system that generates full-color graphics. Extended Color BASIC is available for the TRS-80 Color Computer and was developed by Microsoft. In fact, the message:

EXTENDED COLOR BASIC 1.0 COPYRIGHT (C) 1980 BY TANDY UNDER UCENSE FROM MICROSOFT

appears when you turn the Color Computer on. Extended Color BASIC is fast, memory-efficient, and so well designed that anyone (even children) can create graphics shapes in a few minutes. Best of all, it's fun to use and has features that advanced programmers will appreciate.

Getting Into Graphics

If you have a TRS-80 Color Computer, you can add Extended Color BASIC for $99. The computer must be returned to Radio Shack for the modification. Extended Color BASIC also requires 16 K bytes of programmable memory, which, if you don't already have it, adds $119 to the price of modification. The complete Extended Color Computer sells for $599. You'll still need a color monitor—although the family television is still the most popular alternative.

Radio Shack has released the first easyto-use and inexpensive system that generates full-color highresolution graphics.

Graphics Modes

Extended Color BASIC has five distinct graphics modes available—two low-resolution, two medium-resolution, and one highresolution (see table 2). The low- and medium-resolution modes each offer a choice of two-color or four-color modes. When memory space is at a premium, the two-color modes are

handy for space conservation. The high-resolution mode has only a twocolor mode available. Entering any of the five graphics modes is simple—a PMODE command is the first line of any graphics program. The command is followed by the number (0 thru 4) of the graphics mode you wish to use.

Even though the size of the graphics blocks (or pixels) differ widely in the three main graphics modes, all points are plotted on a 256-by-192 grid (49,152 points). This greatly simplifies matters if you decide to modify any program that uses the graphics modes—if you change the resolution, you don't have to change the parameters of the graphics commands.

Color Combinations The TRS-80 Color Computer has

available a set of nine colors (see table 3). It's interesting to note that the powerful Motorola 6847 Video Display Generator, a key component in the Color Computer, has the capability of displaying a very large number of distinct shades. It's possible to take a look at them by turning on the computer, waiting for the Extended Color BASIC message to appear, and then rapidly turning the computer off and on.

Attempting to figure out the color combinations available in each of the

May 1981 © BYTE Publications Inc 37

CIRCLE (x,y), r, c, hw, start, end

Draws a circle, partial circle, or ellipse.

X is the x-coordinate of the

circle's centerpoint. y Is the y-coordinate of the

circle's centerpoint. r is the radius of the circle. Each unit is equal to one graphics point on the screen, c Is a number (0 to 8) which specifies the color of the circle. The number must be one of those specified for the mode/color set combination. If this value Is omitted, the foreground color defaults to the previously specified color.

hw Is the height/width ratio of the circle (from 1 to 255). If it's omitted, 1 (a perfect circle) is used. start is the starting point of the circle (from 0 to 1). This Is optional and If omitted, 0 Is used.

end Is the endpoint of the circle (from 0 to 1). If It's omitted, 1 Is used,

COLOR foreground,backgrourid

.Sets the foreground and bapkground screen colors within limits specified by the mode/color set combination.

foreground Is a color code (0 to B).

background Is the baclcground color (0 to S).

DRAW line

Draws a line (or series of lines) by specifying the direction, angle, and color.

tine Is a string exprlssslon and may Include: Motion Commands

M

Move the draw position

U

Up

D

Down

L

Left

R

Right

E

45-degree angle

F

135-degree angle

Q

225-degree angle

H

315-degree angle

X

Execute a substring

and return

1(4 odes C = Color A = Angle S = Scale Options

N = No update of draw

position B = Blank (no draw, just

move)

EDIT

Allows editing of program lines.

nC Changes n characters. nD Deletes n characters I Allows insertion of new

characters. H Deletes remainder of line and allows insertion of new characters. L Lists current line and continues edit.

nSo Searches for nth occurrence of character c. X Extends line. SHIR Escape from subcommand.

n SPACE Moves cursor n spaces to the right, n Moves cursor n spaces to the left.

QETsteffpo/nf—endpo/nt destination, Q Places the graphics contents of a specified rectangle within a specified array.

startpoint is the coordinate of the upper-left corner of a rectangle on the screen.

endpoint is the coordinate of the lower-rjght corner of the same rectangle. destination Is the name of a predefined array that will store the contents of the rectangle. G tells the computer to store the rectangle's contents with full graphic detail.

LINE 0i1,y1)—0t2,yZ>, a.b

Draws (or erases) a line between two specified points. Also draws a box using the coordinates as the opposing corners. x1,y1 Is the starting position of the line.

x2,y2 is the endpoint of the line, a Is either PSET or PRESET. b Is either B (for box) or BF (for filled box).

PAINT (x,y) .c.b

Fills a specified area with a specified color. (The color Is limited by the mode/color set combination.) X Is an x-coordlnate. y Is a y-coordlnate. 0 Is the color code (from 0 to 8). The color selected must match one of the colors available in the particular mode/ color set combination In use. b Is the border color (Q to 8) at which painting will stop.

PCLEAR n

Clears a specified number of .memory pages (1536 bytes each) for graphics use. n Is the number of graphics pages (1 to 8).

PCI.3 color

Clears the video display, co/or Is the number (0 to 8) of one of the colors available for the mode/ color set combination in use. II color is omitted, the existing background color is used.

PCOPY source TO destination

Copies the contents of one • memory page to another memory

page.

source and destination are memory page numbers (1 to 8).

PLAY

Plays music of a specified note(AthruGor1 thru 12), octave

(1 thru 5), volume, note duration, tempo, and pause. It also allows the execution of substrings and will handle the specification of sharps and flats.

PMODE mode, start-page

Selects the graphics mode and the memory page on which a program starts.

Mode is the graphics mode (0 to 4). The default value Is 2. Start-page Is the number of the graphics page (1 to 8) on which the program will start.

PSET (x,y,c)

Turns on selected graphics points. X Is the position o.n the x-axIs. y Is the position on the y-axis, c Is the color of the dot (0 to 8).

PRESET (x,y)

Turns off graphics points which were turned on by the PSET

command.

X is the coordinate on the x-axis. y Is the coordinate on the y-axis.

PUT startpoint—endpoint, source, action Places the graphics contents of a rectangle stored in an array by the GET command at a specified position.

startpoint is the coordinate of the upper-left corner of the rectangle. endpoint is the coordinate of the lower-right comer of the rectangle, source Is the name of a predefined array that contains the data to be written into the rectangle. ac(/on determines how the data is to be written into the rectangle and can be tlie following:

PSET—Sets the points that were set in the orlglnal rectangle. PRESET—Resets the points that were set in the original rectangle. AND—Compares the points stored in the original rectangle with the destination rectangle. If both are set, then the screen point will be set; if not, the screen point is reset.

OR—Compares the points as above. If either Is set, the screen point will remain set. NOT—Reverses the state of each point In the destination rectangle.

SCREEN type, color set

Tells the computer whether you want to use a text screen or a graphics screen and selects the color set.

type is either 0 (text screen) or 1 (graphics screen).

color set is either 0 or 1 (see table 4).

Table 1: Graphics, editing, and music commands available in Extended Color BASIC,

38 May 1981© BYTE PuUicatioiu be

5 PMODE4,l

10 PCLS

20 SCREEN 1,1

30 LINE (0,0)-(255,191 ),PSET

40 LINE (0,191)-(255,0),PSET

50 GOTO 50

5 PMODE 1,1

10 PCLS

20 SCREEN 1,1

25 LINE (0,0)-(255,191),PSET,B

30 LINE (0,191)-(255,0),PSET

40 GOTO 40

5 PMODE 1,1

10 PCLS

20 SCREEN 1,1

25 LINE (0,0)-(255,191),PSET,BF

30 LINE (0,191)-(255,0),PSET

40 GOTO 40

Photo 1: Three examples of the LINE statement in Extended Color BASIC. Photo la shows the high-resolution mode (PMODE 4,1). Photo lb is the low-resolution mode (PMODE 1,1) and shows that when the suffix "B" is added to the LINE command in line 25, a box is created which uses the endpoint coordinates as opposing comers. Photo Ic shows what happens when the suffix "BF" is added to line 25. A box is created and filled with the foreground color. (Note that the line created by line 30 was drawn, but it's invisible because it's the same color as the filled box.)

graphics modes is, at first glartce, probably the most complicated aspect of using Extended Color BASIC. Choosing what's called the color set is done by the SCREEN command. This command has two parameters: The first tells the computer whether you want the graphics mode or text mode. The second parameter selects the color set. This is where things get a bit tricky. The three two-color modes (low-, medium-, and high-resolution) each offer a choice of either black and green or black and buff. The two four-color modes (low- and mediumresolution) offer color sets of either green/yellow/blue/red or buff/cyan/ magenta/orange. None of the graphics modes allow you to use all nine colors at one time.

A further "complication" is the COLOR command, which instructs the computer to use specified foreground/background colors. The

specified color codes must be in the allowable color set for the graphics mode you're using (see table 4)— otherwise you'll be greeted with an error message when you attempt to run the program.

Extended Color BASIC divides the available

graphics memory Into eight pages of 1536 bytes each.

Although all this seems extremely complicated, I found that within a few hours of using Extended Color BASIC, the graphics modes and available color sets became second nature. Besides, the system sets default values for you if you don't want to bother remembering all the combinations at first.

Graphics Pages

Extended Color BASIC divides the available graphics memory into eight pages of 1536 bytes each. An optional PCLEAR command can be used in the program to specify the number of pages you want to use. (The default is 4.) A PCOPY command is also available which can copy the contents of one page into another page (as long as the new page was allocated by PCLEAR). In addition, the PMODE command has a second parameter that specifies which page to start the program on.

It doesn't take long to realize that the memory pages offer a number of interesting and creative possibilities. Switching between pages offers the opportunity for limited animation— especially since it's possible to update

Code

Color

0

Black

t

Green

t

Yellow

3

Blue

4

R0d

S

Buff

t

Cyan

7

Magenta

S

Orange

Table 3: Colors available on the TRS-80 Color Computer.

PMODE Number Grid Size Color Mode Memory Pages Used

4 256 by 192 Two-color 4

3 128 by 192 Four-color 4

2 128 by 192 Two-color t

1 128 by 96 Four-color 2

0 128 by 96 Two-color 1

Table 2: The five graphics modes of Extended Color BASIC (two low-resolution, two medium-resolution, and one high-resolution). All modes are selected by the PMODE command and are mapped onto a 256 by 192 grid.

May 1981 © BYTE Publications Inc 39

(a)

o

5 PMODE4,l

10 PCLS

20 SCREEN 1,1

30 CIRCLE {128,96),95

40 GOTO 40

(b)

m

5 PMODE4,l

10 PCLS

20 SCREEN 1,1

30 CIRCLE (128,96),30„3

40 GOTO 40

ic)

5 PMODE4,l

10 PCLS

20 SCREEN 1,1

30 CIRCLE (I28,96),30,l,l,.25,

40 GOTO 40

.75

|»*i|

10 PMODE4,l

20 PCLS

30 SCREEN 1,0

40 FOR RADIUS = 1 TO 100 STEP 10

50 CIRCLE (128,96),RADIUS

60 NEXT RADIUS

70 GOTO 70

Photo 2: Four variations of Extended Color BASIC'S CIRCLE statement, all in the high-resolution graphics mode. Photo 2a is a simple circle with coordinates (128,96) as the centerpoint and 95 graphics blocks as the radius. In photo 2b, the height/ width ratio has been specified as 3, creating an oval. The ratio can be specified from 0 to 255. If > I, the circle is "higher" than it is wide; if < 1, it is wider than it is high. If the ratio is 0, the circle is infinitely higher than it is wide and becomes a straight line. Photo Ic uses the start and finish parameters to specify which part of the circle to draw. Photo Id uses a single CIRCLE statement and a FOR-NEXT loop to create a bullseye.

one page while another is on the screen.

Creating Graphics

Once you get used to the graphics and color modes, using Extended Color BASIC to actually create graphics displays is easy. Although it IS possible to use the PSET and PRESET commands (the equivalent of the familiar SET and RESET commands found in other TRS-80s), the 50,000 or so graphics points available in the high-resolution mode make the setting of individual points a very time-consuming exercise (although this might be necessary in a few cases).

The people who designed Extended Color BASIC have made it simple— such commands as LINE, CIRCLE, DRAW, and PAINT (see photos) make the creation of very sophisticated shapes an easy job. The mostused commands include:

• LINE—Draws a line between two specified sets of coordinates. It will also draw a box and, if desired, fill the box with the foreground color.

• CIRCLE—Draws a circle with a specified radius at a specified coordinate. You also have the option of changing the height/width ratio and drawing only parts of the circle.

• DRAW—Draws a line or series of lines. You specify the direction, angle, and color.

• PAINT—Fills a specified area with a color you pick.

• GET—Places the graphics content of a specified rectangular area of the display within an array.

• PUT—Takes the array used to store the GET information and redraws the graphics within an area that you specify.

(For a complete list of Extended Color BASIC graphics commands, see table 1).

Music

Although fast and easy color graphics is the bread and butter feature of Extended Color BASIC, the system has a number of other strong points, including the ability to perform some pretty fancy music. The non-modified version of the TRS-80

Color Computer (without Extended Color BASIC) allows you to create music by the SOUND command, which gives a range of notes from Fj to E7 with a duration of 6/100 to 6/10 seconds. Obviously, there are limitations to this; there is a limited range, each note requires a separate program line, and you have no control over the tempo or volume. Playing all but the most simple tune is a tedious job.

All of those problems have been eliminated in Extended Color BASIC through the use of one powerful command—PLAY. The PLAY com

mand allows you to control the note, octave, duration of notes and pauses, and volume through the use of a single string. You can also execute substrings, making the playing of certain kinds of music a much easier proposition (see listing 1). Notes (over a five-octave range) can be specified by using either the numerals 1 thru 12 or the notes themselves from C to B (including sharps and flats). Duration of notes can be varied from a whole note to a l/255th note I Thirty-one volume levels can be specified, and tempo and pause-length have a range of

40 May 1981 © BYTE PublicaHons Inc

5 PMODE3,l

10 PCLS

20 SCREEN 1,1

30 LINE (0,0)-(255,191),PSET

40 LINE (0,191)-(255,0),PSET

50 CIRCLE (128,96),90

60 PAINT (135,12S),8,8

70 GOTO 70

Photo 3: An example of the PAINT statement. The lines and circles shown are in the medium-resolution twocolor mode (PMODE 3,1). The PAINT statement in line 60 specifies the beginning point of the painting (135,125), the color choice, and the color number at which the painting will stop.

PMODE Number

4

3 2 1 0

Color Set

0 1

0

1

0

1

0

1

0

1

Two-Color Combination Blacl</Green

Blacl</Buff

Black/Green Blacl</Buff

Blacl</Green Blaci</Buff

Four-Color Combination

Green/Yellow/Blue/Red Buff/Cyan/Magenta/Orange

Green/Yellow/Blue/Red Buff/Cyan/Magenta/Orange

Table 4: Color combinations (sets) that can be used within Extended Color BASIC. (Color set is the second parameter of the PMODE command.) The two low- and medium-resolution modes each have a two-color and a four-color set available. The single high-resolution mode is two-color and only allows combinations of black/ green or black/buff.

Listing 1: A demonstration of Extended Color BASIC'S music capabilities. Lines 55 thru 80 create six string variables (A$ thru F$) and assign to them note, duration, octave, tempo, and volume-level information. Line 85 assigns string variable X$, a string of commands to execute (X) substrings A$ thru F$. The music is played by the PLAY command in line 90, which calls the nested substrings.

1 BACK TO BACH ***

5 CL

10 20 25 40 55

75

B0 85 90

G0 B! F

G5 C 70 D

INT 0 9G . STRING$(32 )"*")

INT (a 320 , STRING$(32 )

INT 0 201 I "BACK TO BACH"

R X = 1 TO 1000: NEXT X

= "TG ;o2 ;l2 ;g ;c i-D ;e IF ;l2 iG ;c; PIG ;c;" = "L2;A;L/t;F;GiA;Bi03;L2iCi02ic;piG;c;F;L4iGi E ;d"

= "L2;E;L4;FiE;DiCiL2;oi ;B;o2;La;c;D;EiC" ="L2iE;LiiDiL2;GiL4ic;D;E;FiL2;Gic;piG;c" ="L2;AiL4;FiG;A;Bi03iL2;ci02;ciPiG;c;F;L4;G; E ;d"

= "L2 ;e ;L/j ;f iE ;d ;c ;d iE ;l2 iF ioi iB ;li i02 ;c"

= "XA$ i XB$;XC$!XD$;XE$!XF* i"

AY X$

from 1 to 255. If you're musically inclined, you'll find the PLAY command an interesting one, despite the inability to play chords. Even for one not schooled in musical theory, these capabilities are useful for adding sound to program displays, graphics, and animation.

The Added Extras

Extended Color BASIC adds to the TRS-80 Color Computer commands and functions. This makes it substantially the same as the well-known Radio Shack Level II BASIC. After using the non-extended BASIC for a while, it was good to have back such familiar commands as TRON and TROFF (trace on and off), and ON ERROR GOTO. Functions added include PEEK (strangely enough, nonextended color BASIC does have POKE but not PEEK), SQR, EXP, COS, LOG, TAN, and USR.

There are a number of differences. Since both extended and non-extended color BASIC use device numbers for I/O (input/output) operations (0 for the keyboard and video

screen, —1 for the cassette, and —2 for the printer), OPEN, CLOSE, INPUT, and EOF (end-of-file) statements are available. Therefore, dumping a program to a line printer is done by the PRINT# — 2 command instead of LPRINT.

Also, because Extended Color BASIC includes a USR function, it is possible to call machine-language subroutines from BASIC programs (unlike the non-extended version). The technical information appendix of the Extended Color BASIC manual says, 'The ROM (read-only memory) contains many subroutines that can be called from machine-language pro

grams." From this statement, you might think that a long list of ROM subroutines would be included. Unfortunately, such is not the case. A total of seven follows, all dealing with cassette, joystick, and keyboard I/O. To be fair, the lack of ROM subroutine information is not Radio Shack's fault—its license with Microsoft prevents publication of such information.

Despite the lack of specific subroutine information, there are three new statements within Extended Color BASIC which are designed to help out the machine-language programmer:

May 1981 © BYTE Publications Inc 41

(b)

5 PMODE4,l

10 PCLS

20 SCREEN 1,0

30 DRAW "BM98,96;NU80;NE56;

NR80;NF56;ND80;NG56;NL80;NH56"

40 CIRCLE (98,96),80,1,1,. 125,1

50 CIRCLE (135,110),80,1,1,1,.125

60 LINE (135,110)-(190,167),PSET

70 LINE (135,110)-(235,110),PSET

80 GOTO 80

5 PMODE4,l 10 PCLS 15 SCREEN 1,0

20 DRAW "BM50,50R60D10NL20D20L20NU20L20NU20

L20U20NR20U10" 'TOP VIEW 25 DRAW"BM50,100R20ND20R20ND20R20D20

NL20D10L60U10NR20U20" 'FRONT VIEW 30 DRAW "BM150,100R30D30L30U10NE20U20"

'SIDE VIEW 35 ' OBLIQUE VIEW—LINES 40-60

40 DRAW "BMI50,50U5E15R10BF20BD30NR5L20H25U10

45 DRAW "BM150,50U5F8U15R15H8F8L15F8NR15D15F8

ND10E15NR10H8

50 LINE (175,30)-(200,55),PSET

55 LINE -(200,80),PSET

60 LINE (167,60)-(183,46),PSET

65 GOTO 65

Photo 4: Three examples of the DRAW statement, which allows you to specify the starting point, direction, angle, and color of a figure. The cube in photo 4a was created by DRAWing two squares (lines 25 and 30) and connecting them with four LINE statements (lines 40 thru 70). Photo 4b is an example of the DRAW statement's "no update" option. Each of the lines radiating from the center of the "pie" is drawn individually, with the computer returning each time to the centerpoint of the circle (98,96). The detached "slice" was created using the CIRCLE statement's start/end parameters and two LINE commands. Photo 4c uses all of the parameters of the DRAW statement to create the four projection studies of a figure.

42 May 1981 © BYTE Publications Inc

5 PCLEAR 8

10 PMODE4,l

11 PCLS

12 SCREEN 1,0

13 PI = 3.14159

15 Al = 0: A2 = 2*P1

20 N = 360:A = 50

25 X = (A2-A1)/N

30 FOR I = Al to A2 STEP X

35 R = A * COS (4*1)

40 X = R *SIN(I)

45 Y = R * COS (1)

50 PSET(128 + X,96 + Y,5)

55 NEXT I

60 GOTO 13

/

({,) 10 PMODE4,l

20 PCLS

30 SCREEN 1,0

40 LINE (127,5)-(127,185),PSET

50 LINE (7,95)-(247,95),PSET

60 FOR XSCALE = 7 TO 247 STEP 20

70 PRESET (XSCALE,95)

80 NEXT XSCALE

90 FOR y SCALE = 5 TO 185 STEP 10

100 PRESET (127,YSCALE)

110 NEXTYSCALE

130 FOR X = - 180 TO 180 STEP 1.5

140 AX = X/57.29578

145 XP = X/1.5 + 127

150 Fl = -(SIN(AX)*90) + 95

160 F2 = -(COS(AX)*90) + 95

170 PSET(XP,F1,1): PSET(XP,F2,1)

180 NEXTX

190 GOTO 190

Photo 5: Three high-resolution examples of the use of PSET, SIN, and COS. The eight-leaf clover in photo 5a is changed to a four-leaf clover (photo 5b) by changing the cosine value in line 35 to 2. In photo 5c, the computer uses PSET, SIN, and COS to draw the sine/cosine waves and LINE to draw the x-y axis. Notice that each wave travels 360 degrees (from +180 to —180) and that the x-axis increments 30 degrees at each gradation. This is a good exercise in mapping (scaling down) a program to fit the video display.

May 1981 © BYTE Publicadons Inc 43

• CLOADM—Loads a machine-language program from cassette. You can also specify a memory offset.

• CSAVEM—Writes a machine-language program to cassette.

• DLOADM—Loads a machine-language program at the speed you specify (300 or 1500 bps [bits per second]).

Advanced programmers should be able to use its speed and efficient use of memory space to

avoid the tedium of machine-language programming.

Although a lack of machine-language information might be considered a handicap by some, it is not. One of the most striking features of Extended Color BASIC is that it is fast—despite the fact that the microprocessor runs at the relatively slow speed (for computers) of .894 MHz (million cycles per second). It's evident that the 6809E is an extremely powerful microprocessor. Creating graphics by the PSET (point-bypoint) method is slow, but the LINE, CIRCLE, DRAW, and PAINT statements are surprisingly fast — obviously calling machine-language subroutines in the Extended Color BASIC ROM.

The Editor

The color graphics and musical ability of Extended Color BASIC are the most interesting features; however, the addition of a full-feature editor (once again similar to the Level II BASIC editor) will surely be appreciated. It only takes a couple of times of retyping long program lines to correct a single error to convince any programmer that editing capability is not a luxury.

Documentation

As usual, the Radio Shack people have done an outstanding job of providing a manual aimed squarely at the "average" user of Extended Color BASIC (ie: the non-programmer).

5

PCLEAR 8

50

GOTO 600

60

LINE ((255 - X),(191 - Y))

(X,Y),PSET

61

J = J + 1:IF J > A THEN J =

0:A = RND(50)

63

RETURN

600

REM ROTATING FAN

601

FOR I = 1 TO S STEP 4

602

PMODE 3,1

603

POLS

604

SCREEN 1,0

605

A = 25:X = 0: Y = 0: I = 0

610

FOR X = 0 TO 254

612

COLOR X/32 + 1,5

615

GOSUB 60: NEXT X

620

FOR Y = 0 TO 190

623

COLOR Y/24 +1,5

625

GOSUB 60: NEXT Y

630

FOR X = 255 TO 1 STEP - 1

633

COLOR X/32 + 1,5

635

GOSUB GO: NEXT X

640

FOR Y = 191 TO 1 STEP -1

643

COLOR Y/24 + 1,5

645

GOSUB 60: NEXT Y

650

NEXT 1

660

FOR I = 1 TO 5 STEP 4

670 PMODE 3,1

680

SCREEN 1,0

690

FOR T = 1 TO 30: NEXT T

700

NEXT 1

710

GOTO 660

Photo 6: Advanced programming in Extended Color BASIC. The program uses the available parameters of LINE, SCREEN, and COLOR to create a multicolor rotating display.

44

May 1981 © BYTE Publications Inc

Mexadecimal Address

Decimal Address

Contents

0-3FF

0-1023

System Use

OFF

255

Direct Page Memory

3FF

1023

Extended Page Memory

400-5FF

1024-1535

Text Screen Memory

Graphic Screen Memory

600-BFF

1536-3071

Page 1

C00-11FF

3072-4607

Page 2

1200-17FF

4608-6143

Page 3

1800-1DFF

6144-7679

Page 4

1E00-23FF

7680-9215

Page 5

2400-9FF

9216-2559

Page 6

2A00-2FFF

2560-12287

Page 7

3000-35FF

12288-13823

Page 8

Program and Variable

3600-3FFF

13824-16383

Storage

8000-9FFF

37768-40959

Extended Color BASIC

AOOO-BFFF

40960-49151

Color BASIC

COOO-FEFF

49152-65279

Cartridge Memory

FFOO-FFFF

65280^5535

Input/Output

Table 5: TRS-80 Color Computer memory map^ (Map as shovm is with Extended

Color BASIC and 16 K byte.

; of programmable memory installed.)

Technical Writer Jonathan Erickson has written a manual ("documentation" is a dirty word in the halls of Radio Shade, since they feel it connotes non-readability) in Radio Shack's informal, chatty, and very readable style. He's also managed to do this without talking down to the reader. Best of all, the material is well organized so that finding specific information is quick and easy.

Summary

Radio Shack's Extended Color BASIC is a breakthrough in color graphics for personal computers. It's fast, easy-to-use, and capable of producing striking graphics. In addition, advanced programmers should be able to use its speed and efficient use of memory space to avoid the tedium of machine-language programming. It lends itself well to the development of games and is also a great way for children to get involved with programming. For experienced programmers, "getting into" the system in

order to broaden its features will present a challenge and eventually result in even more exciting graphics.

Extended Color BASIC (in its present form) and the TRS-80 Color Computer system do not readily lend themselves to a professional or business environment. The inability to mix graphics and text on the screen makes it difficult to set up charts and graphs. But better things are coming—Radio Shack will introduce a floppy-disk drive for the Color Computer within a few months and also plans to market a low-cost plotter/ printer for the system.

Finally, Extended Color BASIC is the first incarnation of Microsoft's continual development of software dedicated to computer graphics, one of the fastest growing fields of the future. If Extended Color BASIC is an indication of the beginning for personal computers, we can expect amazing products in the years to come.B

_At a Glance

Name

Extended Color BASIC

Type of package

Color graphics, music, and

BASIC extension

Manufacturer

Radio Shack

1300 One Tandy Ctr

Fort Worth TX 76102

Price

$99 to add to existing TRS-80 Color Computer; $599 for complete system (less video display)

Format

ROM (read-only memory)

Language used BASIC

Computer needed Radio Shack TRS-80 Color Computer with 16 K bytes of programmable memory.

Documentation

"Going Ahead With Extended Color BASIC"

215 pages, 22 by 28 cm {8V2 by

11 inches)

Of interest to

Everyone

Additional comments

If Extended Color BASIC is to be added to an existing TRS-80 Color Computer, the unit must be returned to Radio Shack for modification.

May 1981 © BYTE Fublkattoiu Inc 45

The Commodore VIC 20 Microcomputer:

A Low-Cost, High-Performance Consumer Computer

"Why haven't you bought a personal computer yet?" This question will elicit varying responses from people interested in buying one. However, most of them fit into two categories: 'They're still too expensive/' or "The ones I can afford are not a good long-range investment." There are some good general-purpose microcomputers around, but they're in the $1000 price range. And some computers cost as little as $200; that's certainly the right price, but you know you're sacrificing something (quality of materials, expandability, etc) to get such a low price.

The Commodore VIC 20 microcomputer may change all this. It is well constructed, has color, sound, and graphics, and is easy to use. It comes with everything needed to use it (except an ordinary color television set), includes a well-written instruction manual, and is supported by a line of optional extensions, peripherals, and documentation (see figure 1). Looking at a picture of the

Acknowledgment

/ would like to thank Ramon Zamora, David

Cole, a}ui the rest of the Avalanche Inc staff for their assistance during the writing of this article.

Gregg Williams Senior Editor

version selling in Japan (photo 1) might cause you to think $600 would be a fair price. It is, compared to the cost of other units. But it does not cost $600—the VIC 20 retails for $299.95.

The Commodore VIC 20 is well constructed, has

color, sound, and graphics, and is easy to

use.

Physical Characteristics

The VIC (which stands for Video Interface Computer) is a small unit, about the size of the main (keyboard) component of the Radio Shack TRS-80 Model I. It measures 40.3 by 20.4 by 7.2 cm (15.9 by 8 by 2.8 inches) and is small enough to easily fit on a work desk or a shelf. In fact, it is small enough to fit into a suitcase (along with its external power supply and RF (radio-frequency) modulator), making it usable as a portable personal computer.

The first thing I noticed about the VIC was its keyboard. It is the equal of any personal-computer keyboard

in both appearance and performance. This is a remarkable accomplishment, almost unbelievable considering the price of the entire unit. Three of its closest competitors, the Atari 400, the Radio Shack TRS-80 Color Computer, and the Sinclair ZX80, have keyboards that are less than perfect as a result of cost cutting. In this respect, the Commodore VIC 20 stands clearly ahead of its competition.

Photo 2a shows the rear panel of the VIC 20. The long slot on the left is used to, plug in memory cartridges, program cartridges, or a VIC Master Control Panel, which allows up to four cartridges to be plugged in. Immediately to the right of the cartridge slot is the TV output socket. The signal from this plug goes directly to a video monitor or through the RF modulator and a TV switch box to a standard television set. (The necessary cable, RF modulator, and switch box are supplied with the VIC.)

The'middle (round) connector on

the rear panel is a serial interface that drives a single 5-inch floppy disk and a printer. Up to five peripheral devices can be daisy-chained through each other to this connector. The next slot to the right (the short rectangular

46 May 1981 © BYTE Publications Inc

MODEM

iCOLOR TV

R F

MODULATOR

UP TO FOUR

PROGRAM OR MEMORY

CARTRIDGES

I I I I

MASTER CONTROL ■BOARD

USER PORT

COMMODORE

PROGRAM

RECORDER

COLOR MONITOR

OR X

.3K-BYTE i :MEMORY SCARTRIDGEi

OR

PROGRAM CARTRIDGE

OR

CASSETTE PORT

SERIAL VIDEO PORT SIGNAL

VIC 20 MICROCOMPUTER

AC

ADAPTER

■ TO 115 VAC

JOYSTICK, — PADDLE,OR LIGHT PEN ;

1MULTIPLE PADDLES, PENS

Figure 1: A block diagram of the Commodore VIC 20 system (shaded components are available at extra cost).

slot) goes to the VIC cassette recorder (which is available separately). The rightmost slot contains a "user port" that can be connected to a printer, a modem, or one of several other peripheral devices. With an optional RS-232C adapter card, this port can

also be used with RS-232C devices.

The left-side panel (see photo 2b) contains (from left to right) a game port, a rocker-type on/off switch, and a socket to receive power from the VIC power supply. The game port, according to Commodore, can

accept a joystick, a light pen, a game paddle, or a VIC Multiple Game Controller (which allows several game devices to be connected to the VIC).

When the VIC 20 is turned on, the video display (a color television tuned to channel 3 or 4) stays dark for about three seconds, then shows the display given in photo 3. The VIC display has 23 lines of 22 characters or graphics symbols per line, with cyan (greenish blue) letters on a white background. The active display area in the VIC is delineated by a border of a different color (in photo 3, a cyan border). The border crisply marks the working area of the VIC. For me, it has the psychological effect of making the screen area seem bigger; this is important, since the VIC displays fewer characters per line than any of its competitors.

VIC Graphics

The VIC 20 graphics character set is virtually identical to that of its predecessors, the Commodore PET and CBM (Commodore Business

Photo 1: The Commodore VIC 20 microcomputer. This unit, a final prototype based on the Japanese version of the VIC microcomputer, differs from the American model only in the model number.

May 1981 © BYTE Publicadons Inc 47

Machine). The standard VIC can display over sixty graphics symbols, shown on the front faces of most of the keys (see photo 1). Since these symbols are directly available from the keyboard and can be stored in string variables and displayed by PRINT statements, it is easy for even the inexperienced BASIC user to combine these symbols into larger pictures. This character-size buildingblock approach is used by Atari, Commodore, Ohio Scientific, and Sinclair. It is a good way to generate graphics that are easy to understand and use without having to design a separate graphics mode. Such graphics are better than simply being able to turn on and off coarse graphics blocks (as in the TRS-80 Models I and III and the Color Computer) because character-oriented graphics allow more detailed images (although, unlike the graphics-blocks system, character graphics do not allow full control of the image).

All the graphics characters in the VIC are accessible directly from the keyboard. For characters shown on the fronts of key caps, pressing either

shift key or the Commodore key (the key in the lower left corner of the keyboard) causes one of these characters to be displayed. Pressing the Commodore key with a given key causes the character on the left half of the front face to be displayed; pressing either shift key with a given key causes the character on the right half to be displayed.

All the graphics characters in the VIC are accessible directly from the keyboard.

Both uppercase and lowercase characters can be displayed, but you lose access to all the characters on the right half of the key front faces. Toggling between this uppercase/lowercase/graphics mode and the default uppercase/graphics mode is done by pressing the shift key, holding it down, pressing the Commodore key, and releasing both keys. The graphics characters on the left half of the key front faces are still available with

Photo 2: Connections to the VIC 20 microcomputer. Photo 2a shows the rear panel of the VIC; front left to right are a slot for program cartridges and connections to a television or video monitor, a floppy disk, a Commodore cassette recorder, and a printer or other peripherals. Photo 2b shows a game device port, an ON/OFF rocker switch, and a connector for an external power supply.

lowercase letters. Commodore grouped what it believes are the most useful graphics characters (ones that might be used with lowercase letters in business applications) on the left half of the key front faces.

Finally, the number of graphics characters that can be displayed is doubled because any character can be displayed as is or in reverse (see photo 3). This can be done immediately or during program execution. Pressing the RVS ON key (the CTRL key plus the 9 key simultaneously) causes all displayed characters to appear in reverse on the screen. (If you are programming and hit the RVS ON key while defining a character string, a reverse R will appear and subsequent keystrokes will not be reversed. However, when you print that string, the reverse R will not appear but will cause all subsequent characters to be displayed in reverse.) Pressing the RVS OFF key (CTRL plus the 0 key) causes all displayed characters to appear unreversed on the screen. (When included in a character string, the RVS OFF key causes all subsequent characters to be displayed normally; its symbol appears in the character string as a reverse underline.)

VIC Color

To quote an adage from photography, "If you can't make it good, make it red." There is an element of truth in that—color does make things more exciting, and it's always one of the most striking features of a microcomputer video display. The VIC has an impressive color display due largely to the complete control you have over the placement and combination of colors.

The VIC allows you to display normal and reversed characters (including all graphics symbols) in eight colors: black, white, red, cyan, purple, green, dark blue, and yellow. The color of the flashing cursor and all subsequent characters displayed on the video screen is set by simultaneously pressing the CTRL key and the appropriate color key (one of the keys numbered 1 through 8). As described for the RVS ON and

48 May 1981 © BYTE Publications Inc

Circle 292 on inquiry card.

what has nine lives, three forms, multiple faces and a price tag that almost disappears?

^ The Magical Microline 80 Printer

It's magic! Well, almost. The Microline 80 wilLrun all day at 80 cps with no duty cycle limitations. The head is warranted for 200,000,000 characters. That translates to over nine years on your TRS-80™ APPLE" or other small computer.

Want to change forms? The magical Microline 80 is three printers disguised as one. There is a whisper-quiet rubber platen for cut sheets and roll paper, pins on nine inch centers for pin feed stock and optional snap-on tractors that adjust to suit all your other forms. The Microline 80 also saves paper by letting you tear off as close as one inch from the last print line.

Want to change your image? The magical Microline 80 really does tricks. It prints upper

and lower ca^ condensed and double width characters an'cl block graphics for charts, graphs and diagrams.

The Microline 80 is not a toy. With two motors, a rugged cast aluminum base and a head you never have to throw away, the Microline 80 is built to handle the most demanding business applications.

Which brings us to the biggest magic of all, the price tag, the one that almost disappears. If we're not the lowest, we are so close that it doesn't matter. There are stocking Microline distributors throughout the country. Call or write today for the name of the one near you and the price of the Magical Microline 80.

OKIDATA

Okidata Corporation, 111 Gaither Drive, Mount Laurel, New Jersey 08054 609-235-2600

Okidata is a subsidiary of Oki Electric Industry Company, Ltd.

Photo 3: The VIC 20 video display iinmediately after being turned on.

RVS OFF keys, pressing a color key within a character string causes a reverse character to be placed in the string. This tells the VIC not to immediately change the display color, but to change it when that string is printed. Photo 5 shows the eight colors available, each of which is displayed by printing the corresponding color control character followed by a line of reverse spaces (which appear as solid squares of the current color). The computer displays all ouput in the current color. In photo 5, since the last color used was yellow, the VIC responds with its end-of-program message in yellow.

The VIC also allows you to change the background color of the working area in the center and the border that surrounds it. Choose from sixteen background colors and eight border colors (ie: 128 background/border combinations). The two are changed by executing (either directly or from a program) the statement:

Photo 4: Tlie character set of the VIC 20. Any cliaracter can be displayed in reverse.

POKE 36879,X

where X is a value as given in table 1. The background colors can be any of the eight character colors or orange, light orange, pink, light cyan, light purple, light green, light blue, or light yellow. The border colors can be any of the eight character colors.

An unusual thing about the VIC is that the background color can change independently of the character color (other color microcomputers can't do this). Combined with the color and reverse keys, this allows a tremendous amount of control over the video display. Photos 6a and 6b show a run of a program differing only in the value poked to memory location 36,879. Photo 6a shows a light green background and a cyan border; this was accomplished by poking the value 219 to that location. Photo 6b shows a light cyan background and a red border; this was accomplished by poking the value 186 to that location.

Photo 5: The eight character colors available on the VIC 20. All characters can be displayed in any of these colors.

In addition, notice the two sets of angle brackets on each line. The first set contains an X symbol, a space, and a small square. The second set contains the reverse of each of these characters. Notice the role of the background and character colors in these reversed and nonreversed characters. If the background color were changed with those characters on the screen, the characters would assume the new background color but retain the old character color.

Photo 7 contains a listing of the program that produced photo 6b. Several control characters appear in this listing as seemingly arbitrary reverse characters. These are screenmanipulation characters stored for later use because they appear within a character string; if a quote mark had not been previously typed on the same line, the character would have been executed immediately and would not have appeared on the screen. The reverse heart in line 100 is the VIC symbol to clear the screen and put the cursor in the upper left corner. The reverse R and reverse underline in line 110 correspond to the RVS ON and RVS OFF keys, respectively. They cause the three characters between them to be displayed in reverse. The reverse characters in lines 120 through 180 are the result of pressing the corresponding color keys (CTRL plus the keys 1 through 8, respectively). They cause all printed characters to be displayed in the given color, as shown in photo 6b.

The VIC video display is memorymapped (ie: the contents of the screen are determined by the contents of a given range of memory locations inside the VIC). Because of this, the

Background Border

Black

White

Red

Cyan

Purple

Green

Blue

Yellow

Black

8

9

10

11

12

13

14

15

White

24

25

26

27

28

29

30

31

Red

40

41

42

43

44

45

46

47

Cyan

56

57

58

59

60

61

62

63

Purple

72

73

74

75

76

77

78

79

Green

88

89

90

91

92

93

94

95

Blue

104

105

106

107

108

109

110

111

Yellow

120

121

122

123

124

125

126

127

Orange

136

137

138

139

140

141

142

143

Light orange

152

153

154

155

156

157

158

159

Pink

168

169

170

171

172

173

174

175

Light cyan

184

185

186

187

188

189

190

191

Light purple

200

201

202

203

204

205

206

207

Light green

216

217

218

219

220

221

222

223

Light blue

232

233

234

235

236

237

238

239

Light yellow

248

249

250

251

252

253

254

255

Table 1: Background and border color combinations in the VIC 20 microcoi)iputer. Poking decimal location 36,879 with the values given hi this table gives a video display with the colors shown.

50 May 1981 © BYTE Publications Inc

For years many small business system buyers thought that in order to get "real" performance and enough storage to be a "real" business system they would have to sacrifice the family jewels.

But with the introduction of the Smoke Signal Chieftain series office computers a lot of people's minds have been changed.

Because we designed the highly reliable Chieftain small business system with the most innovative combination of performance and efficiency around.

At your fingertips there are 64,000 characters of random access memory and you can address anywhere from 740,000 characters to 2 million characters with Smoke Signals's new double density controller. For larger concerns, there's a 20M byte hard disk available.

At a time when other small computer manufacturers tell you "you're on your own", Smoke Signal offers an abundance of easy-to-use software programs such as order entry, inventory control,

accounts receivable, invoice entry, payroll, word processing and much, much more. There's BASIC, COBOL and FORTRAN - even a multi-user BOS (Business Operating System) that allows for numerous users simultaneously.

Chieftain systems starting at under $200.00 per month display performance on par with systems costing twice to three times as much.

So call (213)889-9340 for your nearest authorized Smoke Signal dealer demonstrate the Chieftain's high reliability and

ease of operation. For dealers only, circle 371

All other inquiries, circle 372

he'll be glad to

SHOKE SI6NU

BROUGOINe

31336 Via Colinas, Westlake Village, California 91361, (213) 889-9340

screen can be directly manipulated by poking values into certain memory locations. Memory locations 7680 through 8185 (decimal) contain the code for a given character; memory locations 38,400 through 38,905 contain the code for the color of the respective character. Locations 7600 and 38,400 determine the character in

Photo 6: Variations in character, background, and border colors on the VIC 20. Photos 6a and 6b differ only in the value stored in location 32,879, which determines the background color (from sixteen choices) and the border color (from eight choices).

. m>

PR 11 ( T

" - f\

»l

1 . ■ T

P-P IflT

(1

r-' P- I r 1 T

rl

1 -1 r.i

f ■ f-- Kir

'.'rir i

(1

I f-- u n

•■,1P'.JF;F-L_E

il

[ . . n

il

I -;-n

( [ M T

j:|

lee

111 r

Photo 7: A VIC BASIC program utilizing color, graphics, and reverse video. This program produces the video display shown in photo 6b. The reverse character before each color word in the PRINT statements is a control character determinitig the color of everything displayed after it. See the text for details.

the upper left corner. Locations 7601 and 38,401 determine the character to its right, and so on down to the character in the lower right corner.

VIC Sound and BASIC

The VIC 20 can produce three independent "voices" of music and one voice of noise through the speaker of the attached television set. Each voice, covering a three-octave range, covers a different part of the audio spectrum. The voices are labeled "tenor," "alto," and "soprano"; they are activated by poking a number between 128 and 254 into locations 36,874 through 36,876. The noise generator is similarly activated at location 36,877, and an overall volume control (which takes values between 0 and 15) is located at

36,878. Table 2 lists important memory locations in the VIC 20. Table 3 lists the values to be poked into the music-voice locations to give a certain musical pitch within the threeoctave range of that voice.

VIC BASIC is a version of Microsoft BASIC modified by Commodore. It is a full-blown BASIC with the features found on most microcomputers, allowing the VIC to accept other BASIC programs with little or no modification. A list of BASIC keywords accepted by the VIC is given in table 4. The keywords listed have the standard definitions given by Microsoft BASIC.

The VIC Product Line

Although prices and availability of VIC peripheral devices were not

Memory Location (in Decimal)

7680 to 8185

36,874

36,875 36,876 36,877

36,878

36.879

38,400 to 38,905

Use

contains cinaracter contents of VIC video display; characters are mapped by row, with location 7680 corresponding to the upper left corner of the display

corresponds to tenor music "voice"; should contain either 0 (for silence) or 128 through 254 (for note; see table 3) corresponds to alto music "voice" corresponds to soprano music "voice"

corresponds to a noise-producing "voice"; accepts values of 0 and 128 through 254; higher values give higher-pitched white-noise sounds volume control for all music and noise "voices"; effective values are 0 through 15

control byte for bacl<ground and border colors; see table 1

contains character color contents of VIC video display; mapped to

video display in the same way as the character contents (see above)

Table 2: Some important memory locations in the VIC 20 microcomputer.

Note

Value

Note

Value

C

135

G

215

C#

143

G#

217

D

147

A

219

D#

151

A#

221

E

159

B

223

F

163

C

225

F#

167

C#

227

G

175

D

228

G#

179

D#

229

A

183

E

231

A#

187

F

232

B

191

F#

233

C

195

G

235

C#

199

G#

236

D

201

A

237

D§

203

A#

238

E

207

B

239

F

209

C

240

F#

212

C#

241

Table 3: Values used in the generation of music on the VIC 20 microcomputer. On the VIC. these values are stored in memory locations 36,874 through 36,876 to generate the appropriate note within the three-octave range of a given nnisic voice.

52 May 1981 © BYTE Publications Inc

Circle 304 on inquiry card.

IT WAS INEVITABLE

Sooner or later, someone had to take all this proven microcomputer hardware and software technology and wrap it up in a portable package at a price that shocks the industry, Adam Osborne decided to do it sooner.

The OSBORNE 1®, from Osborne Computer Corporation. You get full CP/M® disk computer capabilities— Z80A® CPU, 64K bytes of RAM memory, a full business keyboard, a built-in monitor, and two floppy drives with 100K bytes each of storage. You get two interfaces, the IEEE 488 and the RS-232C. Just connect a printer, via either interface.

Software? You get CP/M®, CBASIC-2®, Microsoft BASIC®, the WORDSTAR® word processing system with the MAILMERGE® mailing list feature, andtheSUPERCALC® electronic spreadsheet package. All standard. All for $1795.

And it's portable. When the keyboard is clipped over the display panel, only the weatherproof brushed aluminum case is exposed. (There are even optional modem electronics, couplers, battery packs, and external monitor connections, providing practically unlimited system portability.)

It's all business. The OSBORNE 1 delivers significant productivity at an irresistable price. At $1795, its immediata and lasting success as a personal business computer is, quite simply, inevitable.

COMPUTER CORPORATION

26500 Corporate Avenue Hayward, California 94545 (415) 887-8080

Orders for the Osborne 1 Computer can be placed over the telephone at (415) 887-8080. Your order will be forwarded by the factory for delivery by your nearest authorized Osborne 1 dealer.

definite at press time. Commodore has announced an extensive line of products to be "introduced during and throughout 1981." (By the time you read this, Commodore expects to have the VIC computer itself available through Commodore dealers.) This list of peripheral devices and accessories includes: • Memory-expansion products —

Commodore will sell a line of cartridges that add programmable memory to the VIC, increasing the size and complexity of programs that can be run. A 3 K-byte cartridge can be plugged directly into the VIC, and 8 and 16 K-byte cartridges can be plugged in through a Master Control Panel that plugs into the VIC cartridge slot and accepts up to four car

tridges. The maximum amount of programmable memory is 32 K bytes.

• Storage peripherals—Commodore will sell both a low-cost cassette recorder (although existing Commodore recorders work with the VIC) and a low-cost single 5-inch floppydisk drive. The disk drive will hold up to 170 K bytes of data.

• Other peripherals—These include a dot-matrix printer, joysticks, light pens, game paddles, and a Multiple Game Controller (discussed earlier).

• Interfaces—Commodore plans two interfaces for the VIC, a modem and an IEEE-488 bus interface. The modem allows communication with other computers over telephone lines. The IEEE-488 interface allows the VIC (like the PET and CBM machines) to interface with PET peripherals and a wide variety of test instruments and devices that use this standard bus.

• Firmware—A wide range of software will be distributed in cartridge form; three firmware cartridges have already been announced. The first, the RS-232C Interface Cartridge, allows you to use the VIC and a modem to communicate with other computers and access information utilities like MicroNet and The Source. The second, the VIC Programming Cartridge, will include a machine-language monitor and a number of utility functions useful during programming; it will also use the four function keys (on the righthand side of the keyboard) to execute predetermined functions. The third, the VIC Super Expander Cartridge, will add 3 K bytes of programmable memory, a new level of highresolution graphics, and additional music-related capabilities. The highresolution graphics (which I have not seen) are said to be excellent (176 rows by 176 columns of graphics dots, also called pixels).

• Documentation—In addition to the VIC User's Manual, supplied with the VIC, Commodore plans a series of book-plus-cartridge packages explaining several aspects of using and programming the VIC. (Documentation is discussed in greater detail later in this article.)

Arithmetic Operators:

ABS, ATN, LET, SGN. INT, SQR, RND, LOG (to base e). EXP (to base e), COS, SIN, TAN, +, -,*,/, I (exponentiation), <, >, =

Character Operators:

CHR$, ASC, SPC, TAB, LEN, STR$, VAL, LEFTS, RIGHTS, MIDS, + (to concatenate

strings)

Control Words:

FOR, TO, STEP, NEXT, GOTO, IF, THEN, GOSUB, RETURN, ON (used with GOTO and GOSUB), WAIT, END, USR

File and I/O Words:

OPEN, CLOSE, INPUT, INPUT#n, PRINT, PRINT#n, GET, READ, DATA, DIM, RESTORE

Command Words:

RUN, STOP, LOAD, SAVE, VERIFY, CONT, LIST, NEW, CLR

Miscellaneous Words:

AND, OR, REM, DEF FNx, FNx, POKE, NOT, FRE, PEEK

Table 4: A list of VIC BASIC keywords.

Spoken to your Apple* TAI If Tfl YflllR that's more, speech reclately? lflU% lU lUUn ognition is also available for

With the Heuristics™ 2000 A DDI C CDD ^' computers, with our speech recognition boarrl, you can Hi r LC 1 Ull Heuristics 20S and 50 boards, train your Apple computer to A^iiif ^OCO The 2000 also makes a recognize 64 words or phrases 11N lY a t« 3 "^'^ practical starter system of your choice (or multiples v ^ f/,g Heuristics 5000

thereof). Any command for any application. and 7000 industrial/commercial speech

The advanced Heuristics 2000, with micro- recognition units. These commercial units phone included brings a whole new hands- start at $2500. off approach to data entry and program So the next time you have data to enter

control - for a surprisingly low $259. An words to process or menus to select, don't work

optional head-set your fingers to thebone.

microphone (shown UCIIDICTIPC Qflfin Talk to your Apple above) is also available. nCUlllOIIUll I.UUU instead

The talk of the computer industry."^

Heurisl'KS, inc.. 1285 Hammerwood Avenue. Sunnyvale, CA 94086 • 408/734-8532

54 May 1981 © BYTE Publications Inc

Circle 344 on inquiry card.

SiniGIIIRED SYSIEMS

ANYIHUIGUSSISGHEAIMG

Penny wise and software foolisti. One of tfie best ways to cheat your business is to waste a whole lot of time on solutions that don't work, or that can't grow with your business. And frankly we get phone calls every day from computer users who've tried to get by on "bargain" software, and found that "bargain" software is the most expensive kind a business can own.

Here's a fact: if you have a real need for a computer in any of these areas: General Ledger Accounts Receivable Accounts Payable Order Entry Inventory Control Payroll,

any business software less than Structured Systems Financial Software is cheating your business. You'll cheat yourself out of lots of time. Time spent with

systems which aren't designed for high volume use. You'll cheat yourself out of reliable audit controls and reliable error prevention features. Out of the training you invest in a system you outgrow when you need to add more disk storage, more customers, more data. You'll be cheating yourself out of a software bargain in the truest sense of the word—the greatest value for your dollar.

CP/M® microcomputer systems can do the job of minicomputers. Structured Systems software makes that potential a reality. Right now, hundreds of businesses are profiting from the financial controls and operating efficiency of SSG financial software. So can yours.

^ Take it easy on yourself. But sentence your computer to hard labor.

Please send more information on your

□ General Ledger

□ Accounts Payable

Name

□ Accounts Receivable

□ Payroll

□ Order Entry

□ Inventory Control

L

Company

Address

City State Zip Teleptione (

CP/M is a registered trademark of Digital Researcti.

Structured Systems Group

5204Claremont, Oakland, •/California94618 (415) 5471567 incorporated!

Circle 388 on inquiry card.

BYTE May 1981 55

Human Engineering on the VIC

When the microcomputer industry was smaller, hobbyists put up with about anything in a computer as long as it worked. But now that major corporations are marketing microcomputers for the general public, human engineering—the design of systems to make them easy and efficient to use—has become the most important factor in the usability of computer

systems. The VIC deserves high marks in human engineering because it is easy to understand and use.

The VIC . keyboard is one of the best I've seen. It is well constructed and has a good feel during typing. The key names on the top and front faces of the keys are highly visible and easy to read. In most cases, key functions have been wisely chosen and named. For example, the key

used to stop a program from executing is labeled as the RUN/STOP key. Pressing it (instead of the arbitrary control-C combination used by many computers) causes the VIC to stop executing the program and print out the line number where the program was stopped. Use of the CLR/HOME (clear-screen-and-homecursor-to-upper-left-corner/homecursor) and INST/DEL (insert/delete

Name of Computer

Atari 400

Commodore VIC 20

Otiio Scientific Challenger IP

Radio Shack TRS-80 Color

Sinclair ZX80

Microprocessor used

6502

6502A

6502

6809E

Z80A

System clock frequency

1.8 MHz

slightly more than 1 Ninz

1 MHz

slightly less than

1 Mnz

3.25 MHz

List price

$499/$630 (two models, 8 K

1 C U'\

or 1 D n.;

$399.95

$479

$399

$199.95

Type of keyboard

touch-sensitive Mat panel; slightly smaller than

ilUllncil KoyuUdfU

full-size normal keyboard; very good leei

full-size normal keyboard

full-size normal keyboard; keys have leel

Ul LrdlOUialUf

buttons (not good)

touch-sensitive flat panel; much smaller than (lumiai Kcyuuaro

Amount of progrannmable memory supplied

tJ r\ Ul 1 D IN UylBS

(see above)

0 r\ uyies

o w uyies

4 r\ Dyies

1 IS uyies

Maximum programmable memory possible

16 K bytes

32 K bytes

32 K bytes

16 K bytes

16 K bytes

Type of BASIC

full BASIC

full BASIC

full BASIC

limited BASIC (extended BASIC for more sophisticated music and graphics at extra cost)

limited BASIC (extended BASIC available at extra cost)

Video screen size (in characters)

1D rows uy oz columns

rows Dy tL^i columns

24 rows by 24 columns or 12 rows by 48 columns

16 rows by 32 columns

24 rows by 32 columns

Lowercase letters available?

yes

yes

yes

accepts lowercase letters but displays uppercase as inverse capitals

no

Color available?

yes

yes

yes. at extra cost ($229 extra)

yes

no

Graphics characters available?

yes; characters available from keyboard

yes; characters available from keyboard

yes; graphics available only through POKE and CHR$ statements

no, but unit color block is Vt normal character size

yes; characters available from keyboard

High-resolution graphics available?

yes. Included (320 by 192 pixels)

yes, at extra cost (176 by 176 pixels)

no

yes, at extra cost (256 by 192 pixels)

no

Music available?

yes, three voices of music; can mix noise with each voice

yes, three voices of music, one of noise

yes, one voice of music (needs external speaker and amplifier)

yes, one voice of music

no

Extensions to BASIC for color, low-resolution graphics, and music?

yes, uses BASIC commands to manipulate all three

no, uses control characters and pokes to manipulate all three

no, uses pokes to manipulate all three

yes, uses BASIC commands to manipulate all three

low-resolution graphics available from keyboard

Uses program cartridges?

yes

yes

no

yes

no

Machirie-language monitor Included?

no

no

yes

yes

no

Assembly-language assembler available (at extra cost)?

yes

yes

yes

no

no

Table 5: A comparison of five

low-cost microcomputers, including the Commodore VIC20.

56 May 1981 © BYTE Publications Inc

Meet the HP Series 80: Hewlett-Packard's newone-on-one computing systems for professionals.

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SERIES 80, VISICALC™ PLUS AND YOU

HP's VisiCalc™ PLUS is a major new software tool. It's an electronic worksheet that instantly recalculates results as you change the variables. You ask the what-if questions and immediately see their effects on your solution. No programming is necessary... you can become proficient with VisiCalc™ PLUS in a few hours... and then watch your horizons broaden. VisiCalc™ PLUS features many powerful functions including statistical analysis tools and the entire HP Series 80 BASIC math set. Plus graphics! Create professional presentations with curve-fitting plots, stacked or clustered bar-graphs, exploded pie-charts and line graphs, all in up to four colors, on paper or transparencies.

ONLY FROM HEWLETT-PACKARD

HP Series 80 personal computing systems are part of a forty-year tradition of electronic products built to uncompromising standards of excellence. Additionally, HP Series 80 products are serviced by HP technicians and on-site service contracts are now available. We urge you to judge for yourself with a hands-on, one-on-one demonstration at your HP dealer. For locations, call TOLL-FREE 800-547-3400, Dept. 283A, except Alaska/Hawaii. In Oregon call 758-1010. Or write Hewlett-Packard, Corvallis, Oregon 97330, Dept. 283A.

611/04

HP St-rk-s 80 Personal Computer.s lor Proli-s.sionals: HP-85 ($32?0*l and HP-83 ($2250*) .spi;cilication.s: 16K RAM expands to 32K, 32K ROM expands to 80K; CRT wirh integrated Kraphics; (HP-85 only; built-in thermal printer, cassette tape unit): Soltware includes VisiCalc'" PLUS. Information Mana^;ement. Graphics Presentations. Surveyinf;. Data Commtinications (Spring '81), Statistics, Regression Analysis, Math, Linear Programming, Waveform & Circuit Analysis, BASIC Training. HP peripherals incltide floppy discs, printers and plotters. VisiCalc is a trademark of Personal Software, Inc.

•Suggested retail price excluding applicable state and local taxes —Continental U.S.A.. Alaska & Hawaii.

HEWLETT PACKARD

Circle 183 on inquiry carij.

text) keys is obvious when they have been used a few times.

The RESTORE key performs a valuable function in a computer where so many changes in character, background, and border color are possible. It resets the VIC to its state when it was turned on, except that it leaves the current program in memory (unlike some reset keys). Finally, the four large keys marked "fl/f2" through "f7/f8" have no predefined use but can be used by a programmer (through use of the GET statement) to produce a specific function within the program. By using the shift key, these four keys can trigger up to eight user-defined functions. These keys are also used in some application cartridges to execute predefined functions.

As I mentioned earlier, the VIC video display is well designed. The large letters are easy to read, even on an inexpensive color television, and

the border around the active area of the display is restful to the eye. The narrow screen width (22 characters) will be a problem for some users, especially people using programs that need to display large amounts of data. Still, the screen width was a design decision reflecting the intended market, and I think that Commodore made a good decision under the circumstances.

Probably the most unexpected feature of the VIC is that it will be able to exchange both tape and disk files with the Commodore PET and CBM machines. Whether or not the program runs correctly on the other machines depends on whether it contains system-dependent code. For example, a CBM program using the full 80 columns of the CBM video display will not run correctly on the VIC, nor will a program larger than 32 K bytes. The ability to exchange data and programs among machines from

_At a Glance.

Name VIC 20

Manufacturer

Commodore Business Machines 950 Rittenhouse Rd Norristown PA 19401 (215) 666-7950

Price $299.95

Dimensions

40.3 by 20.4 by 7.2 cm (15.9 by 8 by 2.8 inches)

Processor name and type 6502, 8-bit

System clock frequency slightly over 1 MHz

Memory 5 K bytes

Mass storage

cassette recorder or floppy disk optional

Other hardware features character-size graphics symbols, keyboard, uppercase and lowercase letters, eight-color foreground and sixteen-color background video display, threepart music generator, external RF (radio-frequency) modulator and power supply, built-in serial port

Software included

16 K-byte VIC BASIC in ROM (read-only memory)

Hardware options

cassette recorder, floppy disk, dot-matrix printer, modem, IEEE-488 interface, joystick, light pen, game paddle, extra memory cartridges (up to a total of 32 K bytes), RS-232C adapter

Software options

VIC Programming Cartridge (includes programming utilities and machine-language monitor), VIC Super Expander Cartridge (adds 3 K bytes more memory, highresolution graphics capability)

the same manufacturer is almost unheard of. One good example of its usefulness is a situation where someone buys several VIC 20s to be used for data entry and feeds the results into a Commodore CBM computer.

I also found the screen-manipulation characters and POKE statements for music easy to use. By manipulating color, graphics, and sound without using any new BASIC keywords. Commodore has achieved two advantages. First, VIC programs are syntactically equivalent to PET programs. Programs can be transferred between machines without syntax errors due to unrecognized keywords; also. Commodore probably developed VIC BASIC faster and at less cost because of its similarity to PET BASIC. Second, VIC BASIC is easier to learn for people who know PET BASIC or another version of Microsoft BASIC.

An interesting thing about the VIC not apparent at first is the lightness of the unit. It literally has fewer components inside than you would expect. This is possible because it is built around a custom "video interface chip" built by MOS Technology for its parent company. Commodore. This integrated circuit handles all the interaction between the 6502 microprocessor (also manufactured by MOS Technology) and the color television (this function is done by a handful of integrated circuits in many other microcomputers). The low component count plus Commodore's ability to manufacture and assemble almost all of the VIC within its own factory account for the lighter weight and extremely low cost of the unit.

One final human-engineering feature of the VIC that will be appreciated by machine-language users and software developers shows Commodore's willingness to learn from hard-earned experience. The developers of VIC BASIC separated a kernel of I/O (input/output) subroutines from the rest of BASIC. They have written these routines as true subroutines and have devised a method for passing parameters to them so they can be used by anyone who wants to develop software for

58 May 1981 © BYTE PublicaUoiu Inc

Circle 11 on Inquiry card.

NEVER UNDERSOLD.

Thats right. If you can find a lower price in this magazine WE WILL BEAT IT! Period.''

S-100 HARDWARE

SD SYSTEMS

Versa Floppy I kit $259

Versa Floppy II kit $349

ExpandoRam II kit $249

ITHICAINTERSYSTEMS . .. .$CALL

ALTOS $CALL

NORTHSTAR $CALL

SUPPLIES

Verbatim Datalife Diskettes

MD595-01,10.1B $26.50

FD34-9000 $30.00

FD34-B000 $44.00

Avery Tabulables 5,000 3)^X15/16 3,000 3M. XI5/16 I.OOOS'/aX 15/16.

. ,.$18.75 . . $14.25 $8.15

Mi Mi Ml

UARCO Paper (prices are FOB S.PJ

9M( X 11.15 or 1 a Lb $25.95

147/8X11,ISorlBLb. .$35.00

SOFTWARE

Microsoft Basic-BO $299

Microsoft Basic Compiler .. $319

Microsoft Fortran-80 $399

Magic Wand $275

Apple Visicalc $113

Pickles and Trout CP/M* .... $175

APPLE HARDWARE

Microsoft Z-80 Softcard . $259

Microsoft Ramcard $170

SSMAIOA&T $165

SYMTEC Apple Light Pen .$219 MOUNTAIN HARDWARE:

Super Talker $270

ROMWRITER $157

INTROUX-10 $180

ROMPLUS+ $162

MUSICSYSTEM S499

Apple Clock $252

Lobo Drive SCALL

Videx80x24 $299

Andromeda $170

M & R Sup-R-Term $299

Enhancer $100

NEC Green Monitor $240

Sanyo Green Monitor .... $240

D.C. Hayes Micromodem .$299 CALIFORNIA COMPUTER SYSTEMS

See our full page ad in this magazine.

PRINTERS

EPSON MX-80 CALL

MX-BO Graphics ROM . . . CALL NEW EPSON MX-80 TF . . CALL

Okidata Microline 80 $415

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Centronics 737 $689

NEC Spinwriter $CALL

NEC w/ Sellum Option .. . $CALL C. Itoh Starwriter 25 cps$1440 C. Itoh Starwriter 45 cps$1770

Diablo 630 $2195

MalibulBS $1995

Malibu200 $CALL

MPiaSG .....$495,

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TRS-80's $CALL

Micropolis 77 track $399

Percom Doubter .. Percom Separator Orchestra 80

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a on all ordara. Vlaa and Maatar Card aooaptad. Navar undaraold affar appllaa only to itama ourrantly dallvarabia from othar ratall vandora at adiiartlaad priea. All navar undaraold offara good aa aupply laata. Plaaaa add tS.OO for all COD ordara. Plaaaa call for Kama net liatad. Wa gladly anawar any quaatlona on all of our hardwara, aoftwara, and auppty naada. Quanltlty diaoounta avallabla. Sohool purah( to figura oompatltora ahlpping and handling ohargaa whan arriving at navar undaraold prioa.

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Requires: 48K CP/M, two drives needed for complete bperation.

DISK DOCTOR: $100.00 Manual Alone: $ 10.00

CP/M Formats: 8" soft sectored, 5" Northstar, 5" MIcropolis Mod II, Vector MZ, Superbrain Dp/QD, Apple II +

Superset

First in Software Technology

All Orders and General Information: SUPERSOFT ASSOCIATES P.O. BOX 1628 CHAMPAIGN, IL 61820 (217) 359-2112

Technical Hot Line: (217) 359-2691 (answered only wflien tectinician is availabie)

CPIM BEGISTERED TRADEMAHK DIQTAL RESEARCH

the VIC. In addition, all I/O routines called by BASIC are called indirectly through programmable-memory pointers holding the addresses of the true I/O routines; in this way, users can substitute their own I/O routines to be executed in place of those provided within the VIC.

These design decisions (which will be documented to interested parties by Commodore) do two things. First, they encourage the potential software developer to write software for the VIC by eliminating the need to write custom I/O routines. Second, they help isolate the structure of VIC BASIC from some machine-language code that may need to be changed; in this way. Commodore can prevent having several versions of VIC BASIC at some time in the future (a problem that plagued the PET and CBM machines).

Problems and Limitations

The VIC 20 is a very good machine, but it is not without some problems; fortunately, none of them are major.

The juxtaposition of several key pairs on the keyboard is unfortunate. First, the CLR/flOME key is next to the INST/DEL key; while inserting or deleting characters in a BASIC line, you may inadvertently clear the screen or return the cursor to the upper left corner of the screen. More annoying are the reversals of the colon and semicolon keys and the RETURN and RESTORE keys (see photo 1). Touch typists and keyboard users are used to finding these key pairs in different positions (eg: the RETURN key in the same row as the top row of letters). Since the VIC keyboard does not have the layout of previous Commodore machines, it is unfortunate that the keyboard was not laid out in a slightly different way.

Another problem has to do with the music voices. Once a music voice is turned on by the appropriate POKE statement, only poking that location to zero, turning off the sound on the television set, or turning off the computer will shut off the sound. Neither stopping the program that turned on the sound nor typing the keyword

Circle 28 on Inquiry card.

Program to Recover "Crashed" DIscettes AUTOMATICALLY!

Maybe it was a lightning storm, static from the rug, or just too late at night to be working. Whatever the cause, when a discette "crashes" and valuable data or programs are destroyed, the loss is enormous, both in time and money.

DISK DOCTOR is a program which automatically recovers bad discettes. Best of all DISK DOCTOR does not require any knowledge of CP/M file structure! If you can operate CP/M, then you can use DISK DOCTOR. The entire system is menu driven with key information displayed.

DISK DOCTOR is comprised of five "wards", each capable of performing a specific discette recovery operation.

• Ward A: Verifies discettes and locks out bad sectors wlttiout touctiing the

good flies that remain.

• Ward B: Copies whatever can be read from a "crashed" file and places It

into a good file under user control.

• Ward C: Copies discettes without stopping for bad sectors. Bad sectors are

replaced by spaces.

• Ward D: "Un-erases" files. That is, Ward D will recover accidentally erased

disk files.

• Ward E: Displays directory of recoverable erased flies.

DISK DOCTOR will pay for itself the first time it Is used.

Best of all, DISK DOCTOR operates almost complete automatically. The small amount of user interaction is explained in the manual as well as prompted by DISK DOCTOR.

fmasitti Lfiarye

Apparat introduces twenty powerful and ec-onomical add-ons for your TRS-80 system. Hardware and Software to increase your capabilities: Soflware

SMART TERI*1II^AL 80—Converts the Model 1 or III to an intelligent terminal. HEWTRIEVE—Rapid search and retrieval of memory/disk for a character string of any length. riEXTEXT—Provides proportional spacing, compressed and extended characters, underlining and so on. Operates on the Centronics 737 printer in conjunction with SCRIPSIT for the Model I. riEXTEXT II—Provides proportional spacing, right justification and so forth, on the MEC Spinwriter 5500 series printers printing in conjunction with SCRIPSIT 11®. BlOrtlC BASIC—Add new functions to BASIC. Editing and array handling functions available. POCKET 80 GAMES—for the Pocket Computer. C-WRITE—Comprehensive client write-up system for the professional accountant. HEWDOS/80—Por the Model III—all the features available on the Model I plus double density. VOCAL SYNTHESIZER-Provides Morse, Spelled and Spoken output of data files through the TRS-80® Vocal Synthesizer,

inTEGRATED SALES AND IPiVEMTORY SYSTEM

— Provides inventory, sales and receivables for manufacturers.

Hardware

CLOCK/CALENDAR/APPOINTMEHT SCHEDULER—Time, date and up to 100 time/date appointment interrupts, PROM BLASTER—Programs 25XX and 27XX 1 to 4K multi and single voltage PROM. MULTI-PROCESSOR EXPERIMENTOR SYSTEM

— Provides a COPS 402 processor with I/O RAM, and a cross assembler for real time or process control requirements.

ASAP (APPARAT SCIEDTinC ARITHMETIC PROCESSOR)—Fast processing of scientific functions.

TRS-80* BUS EXTENDER—Allows up to six hardware products to be plugged into Models I or III bus. Has self-contained power supply.

DISK SEFHRATOR—Improves floppy disk performance required because of insufficient data separation on the Model I. SPEECH I/O MODULES—Voice and sound input and output for the Models I and III. APPARAT CONnECTIOn—Adds auto answer and auto dial modem capabilities to your TRS-80* MODEL III FLOPPY DISK SYSTEM—Add one to four drives plus controller to your Model 111 with up to 2.8 megabytes capacity under riEWDOS/80. WinCHESTER DISK SYSTEM-Fiw to forty megabyte storage with optional tape or floppy backup.

If you're going to upgrade your system, call us about our twenty new TRS-80 Products, or our complete line of add-ons for the TRS-80. You'll find our products innovative and our prices hard to beat. Dealer inquiries welcome. For more information on Apparat's new products, send $1.00 (refundable on your first order) for our 1981 catalog, or call us at (303) 741-1778.

To order any product, call us toll-free (except Alaska, Colorado and Hawaii) at

800-525-7674.

Apparat jnc.

4401 So. lamarac P&rkway, Denver, CO 80237 (303) 741-1778

END will stop it. (The Atari 400 has a

similar problem, but typing END causes it to silence all sound generators.)

Another problem is shielding against RFI (radio-frequency interference). Although the Federal Communications Commission has passed a set of rules to eventually keep personal computers and similar devices from interfering with television and radio reception, most manufacturers have received extra time to modify their products. In the case of Commodore, only units manufactured after March 1981 must meet the new requirements. I have been told by Commodore that unshielded units will be marked as such. If you live in close proximity to other people, I recommend that you wait for a shielded unit. If you use an unshielded VIC, people nearby may not be able to use radios and televisions while the computer is on.

The most serious problem I found can be avoided with some forethought. The VIC tape recorder, once

put into play or record mode, can be started and stopped by the computer. A potential problem occurs when you have just done a LOAD and are about to do a SAVE (to save, for example, a revised version of the program just loaded). When you did the LOAD, the VIC instructed you to press the play button to begin the loading process. When it finished loading the

One of the most important components of a consumer-oriented mfcrocomputer Is Its

documentation,

program, it stopped the tapetransport motor but left the play button depressed. If you then give the SAVE command, the VIC initiates the process, even though the record button has not been pressed. (If no recorder buttons are pressed when the SAVE command is given, the VIC instructs you to press both the play and record button, and the recording pro

cess occurs without error.) The RUN/STOP key will not abort the loading process, although pressing the RUN/STOP and RESTORE keys will. Still, there are two chances to lose the program: one, not realizing that the program is not being recorded; two, realizing it but turning the VIC off from not knowing that the SAVE command can be aborted and restarted.

Documentation

One of the most important components of a consumer-oriented microcomputer is its documentation. Microcomputer documentation was neglected in the past because it was seen as being too expensive and timeconsuming to justify the perceived benefits. Now, however, good documentation can make the difference between the average consumer using or ignoring the same machine. Microcomputer documentation has a heavy burden to carry because of the multiple functions it needs to perform. First, it must tell the user how to unpack the computer, get it running, and use it. with prepackaged software. Second, it must guide the user carefully through the first sessions with the computer (because many people still have some uneasiness or fear of computers). Third, it must educate the user about microcomputers in general so its potential for use can be seen. Fourth, it must document the features of the microcomputer in a way that is both complete and easy to understand.

Commodore recognized the need for good documentation. Avalanche Inc (of Palo Alto, California) has been commissioned to produce several books about the VIC. The first, the VIC User's Manual, is supplied with the VIC and is a good introduction to the VIC and its features. Its style is informal, friendly, and respectful of the reader's intelligence, but it assumes no previous knowledge of computers. There are illustrated chapters on setting the VIC up and on using its graphics, color, and music. Each feature of the VIC is illustrated with several short programs (5 to 25 lines each), making it

Circle 29 on Inquiry card.

SciTronlcs introduces ...

REAL TIME CLOCKS

with full Clock/Calendar Functions

The Worry-free Clocks for People Who Don't Have Time to Worry!!

What makes them worry-free?

• Crystal controlled for high (.002%) accuracy

• Lithium batteiy backup for continuous clock operation (6000 hrs!!!)

• Complete software in BASICincluding programs to Set and

Read clock

• Clock generates interrupts (seconds, minutes, hour) for for^ound/backgroimd operation

Applications:

• Logging Computer on time

• Timing of events

• Use it with the SciTronics Remote Controller for Real Time control of A.C. operated lights and appliances

Versions available for:

• S-100 bus computers

• Apple II computer

• SciTronics RC-80 owners

RTC-100 $159 RTC A $129 RC-80CK $109

Send SciTronics Inc.

Check or s. cieweU St., P.O. Box 5344 ord^'to- Bethlehem, PA 18015 (215) 868-7220

JPkase list system with which you plan to use con^oOer • AHisler Omge ond Visa accepted. COD'S accepted. PA residence add sales tax.

62 May 1981 © BYTE Publications Inc

Circle 359 on Inquiry card.

/

4

i.

Apparat introduces eleven powerful and economical add-ons for your Apple system. Hardware and Software to increase your capabilities:

THE EXTENDER—Extends Applesoft™ by adding these functions:

• Print Using • Auto Line numbering

• Decimal/Hex Conversion • Higli Resolution Screen Color Indication • Single Color Screen Fill and much more...

HANDY DISK—Utility programs and device handlers for the APEX operating system—A powerful alternative to Apple DOS. XFLO—A Block Structured—Pascal type high level language operating under APEX— Mow with floating point arithmetic. ASAP—Apparat's Scientific Arithmetic Processor Board—Faster execution of scientific functions. CLOCK/CALEnDAR/APPOIHTWEriT SCHEDULER—Provides time and date which can be read by the Apple or automatically DMA'd to the video screen. Also maintains up to one hundred times and dates for use in maintaining an appointment calendar.

PROM BLASTER— Programs all IK to 4K PROMS of 25XX of 27XX single or multivoltage types—With all personality modules and read/write software. APPLE ADD-ON FLOPPY DISK DRIVES— Using the highly reliable TAMDOn disk drives —Provides greater capacity in 40 and 80 track single or dual sided versions. Includes software to integrate this greater capacity to the Apple DOS's.

WINCHESTER MICRO DISK—5 to 10

megabyte capacity optional tape backup. Software to integrate this greater capacity to the Apple DOS's.

PASCAL GENERAL LEDGER—Menu driven general ledger program based on the Osborne System. Customized utility for a true turn-key general ledger system. (This is the system we use!)

sir

' J;,

SALES AND INVENTORY SYSTEM—

Inventory, sales and invoicing package. Particularly advantageous in a manufacturing environment.

APEX—The operating system for the Apple II —Total control of your Apple—fast program loading and execution—Flexibility— Efficiency Once you've tried APEX you can never go back to any other Apple DOS.

If you're going to upgrade your system, call us about our eleven new Apple Products, or our complete line of add-ons for the Apple. You'll find our products innovative and our prices hard to beat. Dealer inquiries welcome. For more information on Apparat's new products, send $1.00 (refundable on your first order) for our 1981 catalog, or call us at (303) 741-1778.

To order any product, call us toll-free (except Alaska, Colorado and Hawaii) at

800-525-7674.

Apparat, Inc.

4401 So. T^marac Parkway Denver, CO 80237 (303) 741-1778

easy to begin learning about the computer. Most of the chapters do not rely on material from previous chapters, meaning that the reader can learn about the features in any order.

Avalanche has produced two more books. Introduction to Computing ...On the VIC and Introduction to BASIC Programming...On the VIC. Both books, part of the Commodore Learning Series, are available at extra cost. They are written in the same friendly style and cover the use of the VIC in greater depth. What makes these books so innovative is that each book is sold with a program cartridge containing longer example programs that are used in the book. This allows the reader to learn from longer programs without the drudgery of having to type them in.

Comparison to Other Computers

Table 5 gives a comparison of five low-cost, consumer-oriented microcomputers: the Atari 400, the Commodore VIC 20, the Ohio Scientific Challenger IP, the Radio Shack

TRS-80 Color, and the Sinclair ZX80.

Although the VIC is a very good machine, some of the others have features that may make them the best choice for you. The Atari 400 has the most sophisticated design; it allows detailed video graphics (although they are more difficult to program) and is the logical choice of anyone wanting access to sophisticated arcade-like games. The TRS-80 Color Computer might be the best choice if you want the convenience of getting service and repairs from a Radio Shack store. In any case, the best computer for you depends on your needs and your budget.

Conclusions

• The final verdict on the Commodore VIC 20 is not in yet because of the large amount of hardware and software not yet commercially released. But if the rest of the product line is as good as the VIC 20 microcomputer is, the VIC computer system will be one of the strongest on the market.

• The VIC 20 computer unit is unexcelled as a low-cost, consumeroriented computer. Even with some of its limitations (eg: screen size of 23 rows by 22 columns, maximum programmable memory of 32 K bytes), it makes an impressive showing against more expensive microcomputers like the Apple II, the Radio Shack TRS-80, and the Atari 800.

• The low cost of the VIC ($299.95) is made possible by a custom computerto-video interface circuit that replaces several other integrated circuits and by Commodore's manufacturing most of the VIC at in-hovise factories in Japan.

• The VIC is well designed and easy for the novice to use. A large part of its suitability for first-time users is due to its excellent documentation and attention to human-engineering factors. The unit has some small design flaws, but they are minor. ■

Why Do Professionals Prefer

BECAUSE

• Unique software • Technical support • Quick delivery • Established company • Release 2 CP/M' (some packages under UNIX' and TRSD8S'')

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BECAUSE

Unique swift routing cybernetics response system gives you no-nonsense technical answers that save you time. Call: (714) 848-1922.

Business Medical Real Estate Computer Systems

• NEW RM/COBOL' applications:

• Order Entry/Inventory • Receivables • Payables • General Ledger • Financial Modeling • Client Accounting—and more on the way!

• NSW CBASIC2' applications:

• REAP (Real Estate Acquisition Package).

Software from Cybernetics?

RM/COBOL—The new standard (or microcomputer C0B0L1! The only COBOL for CP/M (also on TRSDOS & UNIX) with alternate keys (multi-key ISAM). CRT screen handling, Interactive debug, and the most uieful Level 2 features. Compatible with RSCOBOL>—but runs faster.

TRS-80>, Model II CP/M—The fastest Mod II CP/M with the most features. Outstanding teaching documentation for newcomers to CP/M, multiple CRT emulation, down loading package, support for CORVUS 10 Mb hard disk. Many additional uter-orlented features.

Plus existing CBASIC2 packages: APH (Automated Patient History)

Osborne & Assoc.—Payroll • Payables/Receivables • General Ledger NAD" {Name and Address) PMS (Property Management System)

Inquire tor details

Trademarks of: 'Ryan-McFarland Corp.. - Compiler Systems, Inc.. 'Digital Research, 'Bel! Telephone Laboratories. Inc.. '■Tandy Corp.. "Verbatim. Inc.. Cybernetics. Inc.. ''Structured Systems Group. Inc.. 'Small Business Applications. Inc.

And system software packages: MAGIC WAND" Editing/Word Processing CBASIC2 Compiler BASIC QSORT' Soft Merge Package

15.15.15.I8.IE. IS IL IS. 15

Distributed in U K. by Microcomputer Applications Ltd Riverside Court, Caverstiam. Reading. England TEL: (07341 470425

8041 Newman Ave., Suite 208 Huntington Beach, CA 92647

(714) 848-1922

64 May 1981 ® BYTE Publications Inc

Circle 110 on Inquiry card.

Circle 409 on Inquiry card.

"My computer helped me write The Final Encyclopedia. I wouldn't trust anything less than Scotch' Brand Diskettes to make a long story short!'

tlitrsy of Ai r fiil^lisriiliij t

Gordon R. Dickson, Science Fiction Author, Minneapolis, Minnesota

Gordon Dickson: a small businessman whose product is his own imagination. He's written more than 40 novels and 150 short stories; his newest work is The Final Encyclopedia. He uses his personal computer and word processing software to maximize his production. All his words-his productare stored on diskettes. He calls up sentences and paragraphs on demand, and gets more rewrite out of the time available. So he depends on Scotch diskettes to save himself production time. Dependable Scotch media can work just as hard for you. Each Scotch diskette is tested before it leaves ourfactory, and certified error-free. So you can expect it to perform exactly right. Scotch 8" and 5Va" diskettes are compatible with computer/diskette systems like TRS-80, Apple, PET, Wang and many others. Get them from your local 3M distributor. For the one nearest you, call toll-free: 800/328-1300. (In Minnesota, call collect: 612/736-9625.) Ask forthe Data Recording Products Division. In Canada, contact 3M Canada, Inc., Ontario.

If it's worth remembering,

it's worth Scotch

Data Recording Products.

3M Hears You..,

3M

Ciarcia's Circuit Cellar

DC Motor Controls

Build a Motorized Platform

Steve Ciarcia POB 582 Glastonbury CT 06033

Many of you grew up as I did, taking all your toys apart. In most cases, the wrapping was scarcely off a gift before a screwdriver was skillfully applied to pry it apart.

I haven't changed much over the years. I still take most of my gadgets apart. Five months ago, I bought the Milton-Bradley Big Trak toy tank for use in a project. Instantly, I had the screwdriver and pliers ready to do their job. I unpacked the Big Trak, installed the batteries, placed it on the floor, and pressed the Test button. The tank beeped a few times and executed a preprogrammed test sequence. Everything worked, so I began to disassemble it. The time from my unpacking the box to unscrewing the case wasn't more than a minute and a half.

I took Big Trak apart because I was interested in the motorized mechanism inside the vehicle. I found it an impressive engineering accomplishment that

such sophisticated control could be provided with inexpensive motors. My previous experience led me to believe that only industrial-quality DC (direct-current) motors could be controlled so well. It seems that many

Photo 1: A PM (permanent-magnet) DC motor can also be used as a generator-type tachometer, or tachometer-generator. When the shaft is turned, a DC current proportional to the speed is produced. In the case shown, a small PM DC motor is secured in a vise, and the shaft is sloiolx/ turned (by the belt attached to the shaft and extending to the lower right). The digital voltmeter above the motor indicates the actual generator output voltage. In this case, the shaft is turning at about 150 rpm.

things have changed since I was a kid: permanent-magnet DC motors aren't what they used to be.

DC motor controls are not the same, either. They are simpler, more accurate, and cheaper. Using DC motors has become relatively easy. It's no longer a black art.

I hope this article discussing the principles of DC motors will dispel your reluctance to experiment with them. First the basics, then some examples of motor use.

What Is a DC Motor?

The DC motor was invented by Michael Faraday early in the nineteenth century. He determined that when a currentcarrying conductor is placed in a magnetic field, a force is applied to the conductor, causing it to move. Shown graphically in figure 1, the direction and magnitude of this force are functions of the conductor current and the direction of the magnetic field. Conversely, moving

66 May 1981 © BYTE Publications Inc

FULL SCREEN EDITOR

The best news since CP M... customizable full screen editing

As a serious computer user you spend much of your time editing, whether it be for program development or word processing. Make the best use of your time with the help of VEDIT, an exceptionally fast and easy to use full screen editor. VEDIT is a highly refined and proven editor which is easy enough for novices to learn and use. Yet its unequalled set of features also makes it the choice of computer professionals. And because VEDIT is user customizable, it adapts to your keyboard, hardware, applications and preferences.

In VEDIT, the screen continuously displays the region of the file being edited, a status line and cursor. Changes are made by first moving the cursor to the text you wish to change. You can then overtype, insert any amount of new text or hit a function key. These changes are immediately reflected on the screen and become the changes to the file.

VEDIT has the features you need, including searching, file handling, text move and macros, plus it has many special features. Like an 'GNDO' key which undoes the changes you mistakenly made to a screen line. The Indent and Undent Keys allow automatic indenting for use with structured programming languages such as Pascal and PL/I. The disk write error recovery lets you delete files or even insert another disk should you run out of disk space during an edit session. And you have the ability to insert a specified line range of another file anywhere in the text Disk access is very fast and VEDIT uses less than 12K of memory. The extensive 70 page, clearly written manual has sections for both the beginning and experienced user.

Tolally User Customizahk'

Included is a setup program which allows you to easily customize many parameters in VEDIT, including the keyboard

layout for all cursor and function keys, screen size, default tab positions, scrolling methods and much more. This setup program requires no programming knowledge or 'patches', but simply prompts you to press a key or enter a parameter.

The CRT version supports all terminals by allowing you to select during setup which terminal VEDIT will run on. Features such as line insert and delete, reverse scroll, status line and reverse video are used on 'smart' terminals. The memory mapped version supports bank select and a hardware cursor such as on the SSM VB3. Special function keys on terminals such as the HI9, Televideo 920C and IBM3101, and keyboards producing 8 bit codes or escape sequences are also supported.

Ordering

Specify the CRT version, your video board or microcomputer, the 8080/Z80 or Z80 code version, and disk format required. (Call for pricing and deliveiy on the CP/M-86 version)

Standard Package: Disk and manual $130

Manual: Price refunded with software purchase $15

VISA and MASTER CARD Welcomed. Attractive Dealer Terms.

iNew CRT Emulation Package

Get the details on our CRT emulation package for S-100 computers, which features the PlICEON V-100, 24x80 video board and our software to give you an exceptionally compatible and high speed alternative to a CRT terminal.

CP/M and MP/M are registered trademarks of Digital Reseatcfi. Inc. Apple 11 is a registered trademark of Apple Computer, Inc. SoftCard is a trademark of Microsoft TRS-80 is a trademark of Tandy Corp.

Morth Star • Cromemco • Heath H8/H89 • SuperBrain • Apple II Softcard • Sorcerer • TRS-80 Model II & Model 1 Most other CP/M Systems with CRT or Memory Mapped Displays • MP/M • CP/M-86

CompuView Products Inc.

618 Louise, Ann Arbor, Michigan 48103 • Telephone (313) 996-1299

Circle 74 on inquiry card.

a conductor through a magnetic field was found to induce a current in the conductor proportional both to the intensity of the field and the velocity of the conductor as it passes through the field.

Faraday found the best way to obtain useful work from this magnetic force. He assembled a rotating diskshaped conductor within the magnetic field. The resultant force vectors caused the disk to spin. To attach current-carrying leads to the spinning conductor, he used sliding contacts.

These two discoveries became the basis of the DC motor and the DC generator. Eventually, the disk was replaced with many turns of wire placed in deep slots of a laminated iron rotor. This part is the armature. The externally applied magnetic field, the stator field, was produced by an electromagnet (or a permanent magnet) and the sliding contacts

Copyright © 1981 by Steven A Ciarcia. All rights reserved.

became carbon brushes and commutators.

The optimum DC-motor configuration has the most conductors in the magnetic field. Maximum force is developed at a right angle to the stator field. Between these positions, the resultant force is a function of the sine of the angles between the two fields. As the rotor turns, the magnetic field rotates with it unless some provision has been made to switch the direction of current flow in individual armature conductors so they maintain the maximum force vector.

This switching is done with a commutator, as shown in figure 2 on page 70. Current flows in through brush A and out through brush B. During clockwise rotation, the current in coils 3 and 6 will have reversed after one sixth of a revolution past the position shown. In fact, after every one sixth of a revolution, the current in two opposite armature conductors changes directions. As a result, the current-flow and field vectors in the

Can your ALPHA MICRO understand:

I want to see every contributor whose donation was more ttian $1,000 and whose zip code is between 06500 and 06575, The status cannot be defaulted but must be pledged or given, yy

Please rank all medications except ampicillin lor me. The diagnosis must not include fracture and the dale of visit should be past 1 5 80 but prior to 14 February 1980, The time of visit must be later than noon but belore 4:30 PIV1, I also want the patient s age to be greater than 2 years 8 months yet younger than 10 yrs.

-r^Um/'TCl-J™ 2.0 UNIVERSAL DATABASE r^AMI UllilVV Ion MANAGEMENT SYSTEM wMN!

□ powerful, very sophisticated English language inquiry processor

□ up lo 80 fields

□ up to 70 characters per Held; more than 5500 characters per record

□ multiple databases of hundreds of thousands of dynamically allocated, tightly packed records possible

□ ultra-fast ISAM retrieval of any (or all) selected text fields

□ user-controlled database design—all liles (even ISAM!) created automatically

□ nine self-formatting field types including cash, age (interval), and phone

□ dataentry and update facilitated by formatted screens and error cliecking

□ optional user-designed entry screens

□ individualized form letters, directories, and documents

□ labels

□ user-designed reports witii column, row, and grand totals

□ automatic transfer of data to and from user application programs

□ automatic transfer of records to create subset or superset databases

□ global field and subfield search-and'replace

□ data encryption and decryption

□ comprehensive documentation—written in English I

□ suitable for business, professional, or scholarly applications

□ no programming or operating skills needed ; youngest known user Is 12 years old!

ALPHA MICRO" . . I . . \

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DERVISH'" trademark '

NewHa?Ln,c^'°^'^t- New Haven, CT 06511 (203) 787-3952

armature occupy a fixed position in space independent of rotation of the coils. This provides steady, uiudirectional torque.

Motor Classification

DC motors are often classified by the type of stator field used. Fractional-horsepower DC motors using electromagnets to generate the stator field are called "wound-field motors." There are three basic types: series field, shunt field, and compound field. A graphic comparison of speed, torque, and current of these three motors is given in figure 3 on page 72.

Series-field motors provide the greatest torque at start-up because the high initial armature current flows through the stator field as well. As the speed increases, the current decreases. This further increases the speed. If not for internal friction and coil-winding energy losses, this type of motor could theoretically run away under no-load conditions. This type of motor is best used where large starting torques are required, such as automotive propulsion. A schematic representation and speed/torque graph are shown in figure 3a.

F^IB sin 9

F=FORCE

B = FLUX DENSITY

I=CURRENT

Figure 1: Simplified diagram of the basic

electromagnetic principles behind the DC motor. When a current-carrying conductor is placed in a magnetic field, the conductor feels a mechanical force, F, in the indicated direction, perpendicular to the current and the magnetic field. The force is greatest when the current is flowing perpendicular to the lines of flux (6 = 90°), as shown here. The force is zero if current flows parallel to the lines of flux (6=0°).

68 May 1981 © BYTE Publications Inc

Circle 361 on inquiry card.

LINES OF MAGNETIC FORCE

PERMANENT MAGNET STATOR

CURRENT FLOW CONDUCTOR PERMANENT MAGNET

ROTOR AND

ARMATURE

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Figure 2: Internal structure of a typical PM (permanent-magnet) DC motor. Brushes transfer current to the armature coils. As the armature rotates, the brushes contact the assembly at different points, reversing the direction of current flow in the appropriate coils to maintain the electromagnetic force and provide continuing torque.

Shunt-field motors, shown in figure 3b, have the armature and field coils connected in parallel. The lower-current field winding, used only for creating a magnetic field and not required to carry the heavy armature current, makes this motor popular for fixed-speed applications. Except at start-up, the shunt-field motor has greater torque than the series-field motor for a given speed.

Compound-field motors have both series- and shunt (parallel)- field windings. These motors exhibit high starting torque and relatively flat function curves for speed/torque characteristics. While useful in providing rotation in one direction, this motor is difficult to reverse since connections to both windings must be reversed in polarity. Complex switching circuits are required for reversal control.

Permanent-Magnet Motors

In a PM (permanent-magnet) motor, the stator field is produced by a permanent magnet, not an electromagnet. The PM motor has a speed/torque curve that is linear over an extended range, as shown in figure 3d.

The obvious advantage of using a permanent magnet is that it requires no electrical power to generate the stator field. Because the actual electrical-to-mechanical energy conversion takes place in the armature, the major part of the power supplied to the electromagnetic field coil in a wound-field motor is lost as heat. The PM motor requires less power and less cooling.

The PM motor is not new. It has been around for many years and was used in your childhood toys. However, high-power PM motors were very expensive and rarely found in the home. Only recently has the in

70 May 1981 © BYTE Publications Inc

Circle 142 on inquiry card.

Unretouched CAT-400 display. 242x2t6:< f6 /iifs per pixel. 128K byte image buffer. Partial picture showri nere lo tiigtiiigtit aeta:l quality. Image processing courtesy of Earth Resources Da: Analysis Systems Inc . 999 McMillan St.. N W.. Atlanta. Ga.

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Features available: Real time video frame grabber input in monochrome or color. Resolutions to 640 pixels per line, 65.536 Simultaneous colors out of a palette of 16 million colors, Standard RS-170 NTSC and RGB

Circle 125 on inquiry card.

video output, and Image memory from 32K to 256K bytes. In addition we carry accessories and a steadily growing line of software support packages.

For more information call or write DIGITAL GRAPHIC SYSTEMS, INC., 407 Califomia Avenue, Palo Alto, Calif. 94306. Telephone 415/ 321-8871.

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BYTE May 1981 71

Circle 319 on inquiry card.

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corporation of new ceramic magnet materials made the PM motor practical for low-cost/high-power applications. Previously, most PM motors used a/nfco-alloy magnets, which are susceptible to demagnetization.

The magnet material in all PM motors is magnetized during manufacture by placing it into a strong electromagnetic field. If, later on, the motor is not carefully regulated while

in use, high armature currents can produce fields exceeding the original magnetization flux. Consequently, this can demagnetize the stator magnet.

The current at which this phenomenon occurs is approximately seven or eight times the stated normal operating current of the motor. A PM motor with a 3 A current rating would have problems at currents exceeding 24 A. While such values seem

SERIES-FIELD MOTOR

( 3o)

0

—OkJUU

SERIES

STATOR-FIELD WINDING

■<Z1

-<Z1

TORQUE

SHUNT-FIELD MOTOR

( 3bj

-<□

-SPEED

SHUNT

STATOR-FIELD WINDING

TORQUE

COMPOUND-FIELD MOTOR

( 3cj

■VJUU^,!

SERIES

STATOR-FIELD WINDING

■<c:i

SHUNT

STATOR-FIELD WINDING

■<z:

-SPEED

TORQUE ■

(3d)

PERMANENT-MAGNET MOTOR

CURRENT

TORQUE•

Figure 3: Different types of DC motors are distinguished by the type of stator field. Three types use an electromagnet to produce the stator field; the fourth uses a permanent magnet. Different methods of connecting windings in the stator electromagnet produce different speed/torque and current/torque function curves.

72 May 1981 ® BYTE Publications Inc

Circle 214 on inquiry card.

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unlikely in normal use, very high currents are often incurred in low-speed, high-torque, pulsed operation. The greatest risk occurs during a hightorque, high-speed, rapid-reverse situation. The sum of the applied voltage and counter EMF (electromotive force) of the motor at the instant of reversal can create excessive current due to relatively low armature resistances. This article primarily covers low-speed PMmotor applications, so this shouldn't be a problem.

Speed Control in PM Motors

Controlling the speed of a PM motor is much easier than controlling a wound-field motor because the speed/torque characteristics are linear. If you apply a fixed voltage to a PM motor, it rotates at a fixed speed. Double the voltage or reduce the torque (load) requirement by half, and the speed increases by a linearly proportional amount.

Therefore, the least complicated speed control is one which adjusts the voltage applied to the armature, This

1N4002

Figure 4: A simple open-loop linear motor-speed control. Operating the controlling transistor in the linear region of its characteristic curve leads to loss of energy as heat.

can be physically accomplished using a rheostat, an autotransformer and rectifier, or a linear transistoramplifier circuit (such as the one shown in figure 4). The objective is to apply a relatively constant current to the armature.

In the case of the linear amplifier, however, considerable power is wasted as heat loss when the control component (here, a transistor) is not fully turned on (saturated). The worst case occurs when high torque is required at low speed. This condition can be overcome by pulsing the power to the armature through an on/off switch or a switching amplifier. The resulting average current creates the same effect as the linear amplifier without the powerdissipation problems.

There are three basic types of switching amplifiers used in PMmotor controls: PWM (pulse-width modulation), PFM (pulse-frequency modulation), and SCR (siliconcontrolled-rectifier) pulse-width modulation. Essential characteristics of these three forms are shown in figure 5 on page 76.

The pulse-width-modulated controller works by switching the full voltage of the DC power supply to the motor on and off at a fixed frequency with a varying duty cycle. At low speeds, the duty cycle is short.

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Circle 259 on inquiry card.

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SIGNATURE

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u

PULSE-WIDTH MODULATION

+ DC —

OV

PULSE-FREQUENCY MODULATION

■l-DC

ov

SCR PULSE-WIDTH MODULATION

OV

/

/

/

/ /

U-S.:

33 ms

Figure 5: Comparison of three basic switching-amplifier control-circuit output waveforms. The controlling semiconductors are saturated; the average amount of electrical current transferred to the motor is limited by rapidly cutting the current off and on.

and the average voltage applied to the armature is low. At high speeds, the duty cycle is much longer, and the average voltage is increased.

The pulse-frequency-modulated controller, on the other hand, switches the DC supply on for a fixed period of time at a varying repetition rate. At slow speeds, the switching frequency is low, and the resulting average applied voltage is low. At higher speeds, the pulse width of the applied power is the same, but the switching frequency is increased to raise the average voltage level.

Figures 6 and 7 on page 78 illustrate simple circuits allowing you to experiment with PWM and PFM speed controls. The components and frequencies in the schematics are selected for high-current DC motors such as those found in electric drills. (For use on high-speed/low-torque hobby motors, the frequencies and pulse widths may require adjustment.) In figure 6, 10 to 100% PWM speed control is accomplished by adjusting the duty cycle of a one-shot (monostable multivibrator) triggered from a fixed 100 Hz frequency source. In figure 7, PFM speed control is obtained by varying the frequency of 1 ms pulses applied to the motor.

The third method, using an SCR as the switching element, is a variation on PWM. SCR speed control is nearly

76 May IWl © BYTE PublicaUoiu Inc

always used at the power-line frequency (50 or 60 Hz). It functions by changing the firing angle (ie: the point in the waveform where conduction is triggered) between 0 and 180 degrees and applying a specific fraction of each voltage waveform to the motor. At low speeds, the firing time is short, resulting in a low average voltage applied to the motor. At high speeds, the firing time becomes longer, resulting in a higher average voltage.

The SCR controller does not have the precise control resolution of the linear amplifier, but its major advantages are high power-conversion efficiency in the switching mode and low forward-voltage drop. The predominant use of SCRs in fractionalhorsepower DC-motor controls is primarily due to the simplicity of the circuitry. A typical wide-range SCR speed-control circuit is shown in schematic form in figure 8 on page 80. Figure 9 illustrates a speed-control circuit which maintains constant speed under varying load conditions.

Closed-Loop Speed Control

The speed-control designs presented so far have been open-loop controllers. They are adequate for setting speeds where torque requirements are constant. For applications where there is a variation in load demand or where constant velocity is required, a closed-loop control system must be

Circle 400 on inquiry card.

KirM

Multi-User

UniFLEX is the first full capability multi-user operating system available for microprocessors. Designed for ttie 6809 and 68000, it offers Its users a very friendly computing environment. After a user 'logs-in' witti his user name and password, any of ttie system programs may be run at will. One user may run ttie text editor whiile anottier runs BASIC and still anotfier runs ttie C compiler. Eacti user operates in hiis own system environment, unaware of othier user activity. Ttie total number of users is only restricted by ttie resources and efficiency of ttie tiardware in use.

Multi-Tasking

UniFLEX is a true multi-tasking operating system. Not only may several users run different programs, but one user may run several programs at a time. For example, a compilation of one file could be initiated wtiile simultaneously making ctianges to anottier file using ttie text editor. New tasks are generated in the system by the 'fork' operation. Tasks may be run in the background or 'locked' in main memory to assist critical response times. Intertask communication is also supported through the 'pipe' mechanism.

Support

The design of UniFLEX, with its hierarchical file system and device independent I/O, allows the creation of a variety of complex support programs. There is currently a wide variety of software available and under development. Included in this list is a Text Processing System for word processing functions, BASIC interpreter and precompiler for general programming and educational use, native C and Pascal compilers for more advanced programming, sort/merge for business applications, and a variety of debug packages. The standard system includes a text editor, assembler, and about forty utility programs. UniFLEX for 6809 is sold with a single CPU license and one years maintenance for $450.00. Additional yearly maintenance is available for $100.00. OEM licenses are also available.

FLEX

UniFLEX is offered for the advanced microprocessor systems. FLEX, the industry standard for 6800 and 6809 systems, is offered for smaller, single user systems. A full line of FLEX support software and OEM licenses are also available.

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Principle of Operation: The ELECTRIC MOUTH stores words in their digital equivalents in ROMs. When words, phrases, and phonemes are desired, they are simply called for by your program and then synthesized into speech. The ELECTRIC MOUTH system requires none of your valuable memory space except for a few addresses if used in memory mapped mode. In most cases, output ports (user selectable) are used.

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sixteen amnerc danger hour minute ready a r

seventeen and degree in near right h s

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Corp.

INPUT FREQUENCY fo-lOOHz

1N4002

/77

Figure 6: A simple PWM (pulse-width-modulated) motor-speed control. The duty cycle of the monostable multivibrator (74121) is adjusted by the variable resistor to change the average integrated (in the mathematical sense) electrical current supplied to the motor through the driving transistors. Pin 14 of the 74121 should be connected to + 5 V, while pin 7 should be connected to ground. The 2N3055 transistor must be mounted on a heat sink.

INPUT FREQUENCY fo»10Hz-lkHz

1N4002

/f7

Figure 7: A simple PFM (pulse-frequency-modulated) motor-speed control. The number of constant-duration pulses supplied to the driving transistors over a given interval controls the speed.

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< CALL TOLL FREE 800-243-7428

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Figure 10a on page 84 shotvs an open-loop controller; figure 10b shows a closed-loop system. Both controllers use an amplification (device to drive the motor. The amplifier block can be broadly interpreted to represent any of the driving methods discussed (PWM, linear amplifier, etc). In the open-loop controller, any variation in load demand causes the motor to speed up or slow down.

The basic difference between the

open- and closed-loop control methods is that the latter uses a sensor attached to the motor shaft to monitor the actual motor speed. The sensor provides a feedback signal proportional to the shaft's speed. This can be compared with the desired value of the signal (the set point) to find out if the motor is running fast or slow. If the speed is too low, the comparator applies more voltage to the amplifier to bring the speed up. When

78 May 1981 © BYTE PublicatiQiu he

Circle 426 on inquiry card.

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1N4002

Figure 8: An SCR- (silicon-controlled rectifier) controlled motor-speed circuit. This method, a variation of PWM (pulse-width modulation), has a wide speed range, high power-conversion efficiency, and low forward-voltage drop across the controlling semiconductor, but not the precise control resolution of a linear-amplifier circuit.

1N1200

TYPICAL FOR 4

680n 1/2W —"Af*—

lOK 2W

SPEED ADJUST

Figure 9: A second type of SCR-controlled motor-speed control. This design has a limited speed range but maintains constant speed under varying load conditions.

the speed sensor indicates the speed is

too high, the comparator reduces the current to the motor, and the speed drops.

The speed sensor is generally a DC generator. This is nothing more than another PM motor operated in reverse. When the armature is turned, its coils cut through the PM statorfield lines, inducing a current in the armature windings. A motor with a rating of 500 rpm per volt, when used as a generator, produces an output of approximately 4 V if the armature is rotated at 2000 rpm. Such generatortype tachometers (or tachometergenerators) are useful for mediumand high-speed applications when they have a reasonably detectable and steady output. Photo 1 shows a PM motor being used as a generator.

At low speeds, an incremental encoder is often used instead of the generator-type tachometer. An in

cremental encoder generates a pulse

when the shaft has rotated through a given angular increment. They are most suitable in low-speed and position-mode controllers. Photo 2 on page 81 shows a simple incremental encoder. More on this later.

Servo Controls

So far, we have discussed openand closed-loop speed controls. We can turn a potentiometer and set a speed of 2000 rpm on a PWMcontroUed motor. We can even attach a tachometer to regulate the speed at this set point. All these controls, however, are scalar and unidirectional. When the speed control is adjusted, we are setting a fixed number of revolutions per minute, rather than attempting to rotate the motor shaft to a particular position or to have it make ten revolutions and stop.

When control systems capable of

DETACHABLE INSERT

80 May 1981 © BYTE PubUcaUona Inc

DETACHABLE INSERT

Operating in Quadrants

The torque/current and torque/ speed function curves of figures 3a, 3b, 3c, and 3d on page 72 all lie in the first quadrant of a Cartesian coordinate system. In these graphs, torque and speed are considered positive when the motor's shaft is rotating in the forward direction, and current is positive or negative according to its direction of flow.

During most modes of operation, the curves remain in the first quadrant; only when sudden stopping and reversing take place do

the curves enter other quadrants.

For instance, in dynamic braking, the inputs to the armature coils are shorted together. As the motor continues to rotate, the existing magnetic field induces in the coils a counter electromotive force that attempts to produce a field opposing the existing field. The opposition of the two fields produces negative torque and surprisingly fast braking action. The current of this counter electromotive force is negative, and the torque/current function curve momentarily moves into the third quadrant.

providing positive- and negativeoutput voltages for four-quadrant operation in conjunction with feedback control are discussed, we are no longer talking about mere speed controls, but about servo systems. Servo systems are usually configured to provide velocity, position, or torque control, or combined velocity/position control. The definition encompasses all DC-motor applications beyond first-quadrant fixed-speed operation (see the text box above). The simplest type of servo opera

tion is a forward/reverse motor control. Reversing the rotation on a PM DC motor is accomplished by reversing the polarity of the applied voltage. While this can be done manually by using a switch, in automatic-control systems it is most frequently done with transistors. Two typical circuits are illustrated as schematic diagrams in figures 11a and lib on page 86. In figure 11a, a forward-control signal turns on transistors Ql and Q4, routing the current through the motor as shown. A

PVioto 2; The most frequently used nongenerator speed-feedback device is the incremental encoder. This is a homemade encoder, consisting of a plastic disk attached to the motor shaft. Around the perimeter of the disk are slots or holes. A light source is placed on one side; a light sensor on the other side. As the shaft turns, the disk interrupts the light seen by the photo sensor and creates a pulsed output with a pulse rate proportional to the speed of the rotation.

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May 1981 © BYTE Publicatioris Inc 81

FRESH IDEAS ARE GROWING AT ALTOS

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Fresh ideas like Altos' new ACS8000-6/MTU single board microcomputer system with a DEI 'A-inch cartridge tape back-up drive, and Shugart's 8-inch floppy and 14-inch Winchester hard disk drives, with total on-line capacities from 14.5 MBytes to 58 MBytes.

The ACS8000-6/MTU joins Altos' growing family of products that branch out to a multitude of single board system configurations to serve the OEM, the business sector, and many other end users. These systems range from the ACS8000-2 with its dual 8-inch floppy disk drives, to the powerful ACS8000-5, which is upgradable to any of Altos' hard disk and multiuser systems.

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Circle 14 on inquiry card.

SPEED SET POINT

AMPLIFIER

Figure 10a: Block diagram of an open-loop controller. Variations in mechanical load cause the motor to speed up or slow dawn.

SPEED SETPOINT

DIRECTION OF ROTATION

FEEDBACK VOLTAGE

SPEED SENSOR (TACHOMETER-QENERATOR)

Figure 10b: Block diagram of a closed-loop controller. The speed sensor detects too-fast or too-slow motion and keeps the motor running without variation in speed over wide variations in load.

reverse-control signal enables transistors Q2 and Q3 to route the current through the motor in the opposite direction. This circuit, frequently called a bridge output, uses only a single DC supply voltage and is generally reserved for use in PWM or PFM controllers. Figure lib shows a complementary output driver. It is more suitable for linear-control operation, and it requires two opposite-polarity power-supply voltages.

Incremental-Motion Systems

Usually, we dori't thirtk of performing positional control with DC motors. Most of our experience has been with 7000 rpm, 3 V PM motors salvaged from toys. However, using special DC motors, it is possible to perform repeatable intermittent or incremental motion. These are the motors generally used in computerperipheral magnetic-tape transports and line-feed mechanisms. In these, it is frequently necessary to run the

motor at fast speeds to achieve high media-slew rates, as well as slow incremental motion. (Stepper motors generally cannot attain the high speeds required.)

The incremental drive is basically a high-performance velocity-controlled

Special DC motors are used In computer peripheral devices

where widely varying speeds are needed.

DC-servo system. The incremental motion is obtained by applying variable-amplitude voltage pulses to the input and accelerating the armature for predetermined periods of time. Figure 12 on page 88 shows the control waveforms.

With the system initially at rest, a high positive step voltage, ti, is applied to the input. This causes the

motor to accelerate almost instantaneously. Shortly thereafter, the voltage is reduced to a level, ti, maintaining constant rotational speed. Some time later, the shaft rotation is stopped by applying a reversepolarity input, ti. Attempting to accelerate in the opposite direction causes the motor to brake. The exact timing of these pulses depends upon the specific motor and torque requirements.

The entire process takes only a few milliseconds and may move the armature a fraction of a revolution. This incremental motion is repeatable, enabling practical application. If, for example, it is applied at 100 steps per second while using an incremental encoder for speed control, the motion will appear to be produced by a high-torque stepper motor.

Build a Motorized Platform

Experimenting with incrementalmotion controls on permanentmagnet DC motors is not as difficult as you might imagine. Once you discover the capabilities, you may find yourself experimenting with different mechanisms, as I have.

The cheapest high-power lowvoltage PM DC motor I found was the one in a hand-held batteryoperated drill. The motor I used was from a Black & Decker Model 9001 ^/4-inch cordless drill. This same motor is probably used in a variety of other tools and appliances, possibly hedge trimmers and the like.

The basic unit consists of a power pack (containing a 4.8 V rechargeable nickel-cadmium battery and a charger) and the motor/drill-chuck assembly. The motor/chuck assembly contains the PM motor, reduction gears, and drill chuck.

A major stumbling block in building a transport mechanism that might be used in a robot has been the expense of the motors and gears. In lightweight assemblies, designers often incorporate ' stepper motors because they are easily controlled and their motion is repeatable. In larger and heavier vehicles, use of stepper motors becomes prohibitively expensive, and alternative drive mechanisms are required.

84 May 1981 © BYTE PublfeaUoiu Inc

Circle 227 on Inquiry card.

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Figure 11a: One of two basic reversing motor-control circuits. This bridge-type switch uses a single DC supply voltage and is used mostly in PWM or PFM controllers.

+ v

Figure lib: A complementary-type reversing circuit. It is more suitable for linearamplifier control operation, while requiring two opposite-polarity power-supply voltages.

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Wiiile I did not intend to build a 300-pound "Son of Robbie," I wanted to experiment with some form of remote-controlled transport. Since the drills contained gear-reduced, low-voltage/high-torque motors and a chuck to attach an axle, it was natural to consider their use. The only problem I envisioned was reducing the nominal 750 rpm motor speed to a fairly constant value around 60 rpm. An incremental-motion controller was the answer.

The result of my experimentation is the motorized platform shown in photos 3, 4, and 5 on pages 90 and 92. A sketch of the major parts is shown in figure 13 on page 88. The platform consists of a T-shaped metal frame with a drive motor on each "arm" and a swivel wheel on the "leg." I designed it in a T shape so the drive motors could provide steering con

trol, as well as forward/backward motion. In a conventional fourwheeled vehicle, this can be accomplished only by turning the axis of two wheels in the direction of the turn. This could not be accommodated in the present mechanism.

With the T shape, steering is like simple rotation. For forward motion, both motors rotate clockwise; for reverse motion, both motors turn counterclockwise. Turns are accomplished by driving the motors in opposite directions. For a right turn, motor A goes clockwise and motor B goes counterclockwise. A left turn, or left rotation, occurs with the opposite settings. The effect is that it rotates in place. Usually, reversing the polarity to the motors is handled through transistor switches, but I found that the voltage drop through the switch

Text continued on page 90 Circle 13 on Inquiry card. »

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(12a)

+ 1.

ARMATURE CURRENT

-I

PEAK

(12b)

COAST

"ACCEL

CEL

STOP

ARMATURE VELOCITY

Figure 12: Precise control can be achieved using incremental-motion controllers. During predetermined periods of time, variable-amplitude voltage pulses are applied to the motor's coils. With the system initially at rest, a high positive step voltage, ti, is applied to the motor. After motion has begun, the voltage is reduced to a lower continuing value, ti- When the motor is to be stopped, a negative braking voltage, fj, is applied.

-SWIVEL WHEEL

DIRECTION OF ROTATION

FUNCTION FORWARD RIGHT TURN LEFT TURN BACKWARD

MOTOR A CW CW COW COW

MOTOR B CW CCW CW CCW

Figure 13: Arrangement of components of the motorized platform. Steering is done in the simplest case by rotation. Both motors turn in the same direction for straight motion, whereas for a turn, one motor turns CW (clockwise) and the other turns CCW (counterclockwise).

88

May 1981 © BYTE Publicalions Inc

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Text continued from page 86:

ing network was too much in this

low-voltage system. Instead, i used

relays to switch polarities and enable

motion.

The greatest design obstacle was the actual velocity-control system.

Even though the drills contained gears, the no-load speed was 750 rpm. With a wheel and axle inserted into the chuck, the platform's uncontrolled speed with no load was 10 feet per second. About 9 inches per second, corresponding to 60 rpm,

seemed considerably more manageable.

To attain this lower speed, an incremental-motion/PWM controller was designed. One controller is required for each motor. The schematic diagram is shown in figure 14 on page 96. Component values were experimentally determined for use with the Black & Decker PM motor specified. Other PM motors may not operate in exactly the same manner.

Basically, the circuit is a closedloop controller, consisting of a comparator, driver amplifier, and speedfeedback sensor. The desired speed is selected through a ten-turn potentiometer. The set-point voltage so derived is compared to an integrated feedback voltage from an optical incremental encoder. If the speed is too slow, the pulses out of the comparator are made longer. If the speed is too fast, the pulses are cut shorter. A negative voltage applied to the driver input between pulses assures complete turnoff.

The low pulse-frequency rate required to keep the speed at or below 60 rpm results in an incrementalmotion condition. The start pulse is at the full DC supply voltage, creating a high-velocity start-up. A reverse-step pulse is not necessary to stop the motor, however, due to the high mechanical load presented to the motor through the gears. They serve to immediately dampen any coasting. The result is smooth, low-speed rotation, in rapid discrete increments, at a predictable constant velocity.

Maintaining constant motor speed is imperative when the motors must run synchronously for forward and backward motion. Turns are not as critical, but you realize what happens when one motor runs faster than another.

The 60 rpm speed is too slow to use a tachometer-generator without considerable complication. Instead, an incremental encoder (shown in photo 6) generates pulses as the wheels turn. Ordinarily, I would have used a slotted or perforated disk interrupting a light beam, but it wouldn't fit in the space available. Instead, I wrapped reflective aluminized tape with black stripes parallel to the axis of rotation around the chuck. An LED (light

Photo 3: A simple application of the DC motor controls presented in this article is to build a small mobile motorized platform. This one uses two battery-operated drill motors and a swiveling furniture caster. The T-shaped structure has complete mobility and can turn and pivot, as well as follow a straight line. The large box in the center of the platform contains the two motor controllers, relays, and batteries.

Photo 4: Close-up of a drive motor on the platform. The motor is from a 4.8 V Black & Decker battery-operated %-inch drill. The drill's case and battery pack have been removed. It is secured to the aluminum T-frame with two U bolts. A %2-inch brass rod that serves as an axle is inserted into each drill chuck. The tires are air-filled syt-inch diameter rubber tires used on model airplanes.

90 May 1981 © BYTE Publications Inc

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emitting diode) and phototransistor sense the light and dark areas of the tape as the shaft rotates. The greater the number of divisions or stripes per inch, the greater the resolution of the feedback system. While I was able to set the same speed on both motors, more encoder divisions would have been better.

Ideas for Computer Control

This article wouldn't be complete unless I described how my motorized platform can be remotely controlled from the computer. Essentially, it requires three signals controlling one power-on/off relay and two forward/reverse relays (10 A contacts).

Text continued on page 98

Photo 5: The rear of the T-frame is supported on a furniture caster. This is a simple scheme allowing motion in any direction.

Photo 6: It was nearly impossible to fit the incremental-encoder disk of photo 2 between the motor and the wheel. Instead, a piece of reflective aluminized tape with black stripes was wrapped around the drill chuck. An infrared LED (light-emitting diode) and phototransistor are aimed at the tape so the light is reflected to the sensor. As the shaft turns, the light is interrupted much the same as the disk version.

92 May 1981 © BYTE Publications Inc

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Figure 14: The motor-control system of the platform, featuring incremental-motion control and reversing capability. Two such circuits were used, one for each motor. Values of the components were experimentally chosen for use with the motor from a Black & Decker Model 9001 portable drill. The 2N3055 transistor must be mounted on a heat sink. The L1F4 phototransistor is made by General Electric.

96 May 1981 © BYTE Publicadoiw Inc

Circle 203 on inquiry card.

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Text continued from page 92: The forward/reverse relays set the intended motor directions, and the power-on/off relay starts both motors. As long as the power is on, the platform goes in the direction set by the two forward/reverse relays.

Computer direction of the relays is accomplished with 3 control-signal bits from a parallel output port. For wireless remote-control operation, the communication control link presented in my article "A ComputerControlled Tank" (BYTE, February 1981, page 44) can easily be adapted to this task.

In Conclusion

You may never see my contraption again. I don't consider this the start of a serious robot-building project. The total expense for the platform was under $50. It was just an experiment. .1 had always wanted to try using inexpensive electric-drill motors as servos. While I had. mixed success, it did serve as a vehicle for a general article on DC-motor control.

Building the platform was the only way to truly test the theory. I was surprised that the final unit, weighing 10 pounds, had no problems with insufficient driving torque (unfor

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For MONEY MAESTRO Home Banking System, mali to:

InnoSys Inc., 2160 Shattuck Ave., Berkeley, CA 94704, (415) 843-8122

Name

Address. City

Slate.

. ZIP_

I I'm interested!

I □ descrlptiye brochure (free)

□ User's Manual ($20.00) I □ dealer Info

I'm sold!

□ MONEY MAESTRO ($200.00) □ 8> CP/M □ SVt' MIcropolls D 5V4' Northstar CP/M SD

Payment: o COD □ checit enclosed amounts.

□ VIsa/Mastercharge #

.exp. date /

Signature

Allow $3.00 Shipping & Handling (overseas: $10.00). CslKomla residents add sales tax.

"today's idea ...

... tomorrow's utility"

I N C O R P I) !< A T t. D

tunately, the small batteries lasted only about 5 minutes in constant use). Even with an additional 5 pounds of payload (a bottle of Hennessy cognac and two heavy BYTEs), it worked well.

I don't expect many of you will try to build a motorized platform. 1 do, however, anticipate that more of you will consider using permanentmagnet DC motors for future designs where you thought only stepper motors could be used. If you already own a battery-operated drill, connect it to the control circuit of figure 6 or figure 9. You will be surprised at the capabilities it demonstrates.

Next Month:

Add a speech-synthesizer circuitboard assembly to your computer. ■

Editor's Note: Steve often refers to previous Circuit Cellar articles as reference material for

the articles he presents each month. These articles are available in reprint books from BYTE Books. 70 Main St, Peterborough NH 03458. Ciarcia's Circuit Cellar covers articles appearing in BYTE from September 1977 thru November 1978. Ciarcia's Circuit Cellar, Volume II presents articles from December 1978 thru June 1980.

Many Circuit Cellar projeas are available as kits. To receive a complete list, circle 100 on the Reader Service card.

References

1. Berger, R C. "Electric Motor Drive Controls." Process Instruments and Controls Handbook. D M Considine, editor. New York:

McGraw-Hill Book Company, 1974.

2. DC Motors, Servo Controls, and Servo Systems. Hopkins MN: Electro-Craft Corporation, 1975.

3. Fitzgerald, A E and Charles Kingsley. Electric Machinery. New York: McGraw-Hill Book Company, 1952.

4. Gardner, Floyd M. Phase-Lock Techniques. New York: John Wiley and Sons, 1966.

5. Mclntyre, R. Electric Motor Control Fundamentals, Second Edition. New York: McGraw-Hill Book Company, 1966.

6. Millermaster, R A, editor. Harwood's Control of Electric Motors, Fourth Edition. New York: John Wiley and Sons, 1970.

7. Sweer, Leon, Thomas Dwyer, and Margot Critchfield. "Controlling Small DC Motors with Analog Signals." BYTE, August 1977, page 18.

8. Walton, Robert L. "Controlling DC Motors." BYTE, July 1978, page 72.

98 May 1981 © BYTE Publicatioiis Inc

Circle 194 on inquiry card.

Circle 156 on inquiry card.

Pump Up Your TRS-80 with the ES/F Mass Storage System

THESE FACTS SPEAK FOR THEMSELVESI

▲ Actual Size

Actual Thickness ▼

CASSETTE

ES/F

MINI-DISK

SPEED 56

(Seconds to load "BlacKiack")

6

(5' wafer)

6W

CAPACITY

(thousands of bytes)

38

(C-20)

64

(75' wafer)

59 (TRSDOS)

RELIABILITY

(Designed for digital data?)

NO

YES

YES

SYSTEM COST

(First unit plus interface)

$60

$250

$800

MEDIA COST

(in quantities of ten)

$3.10 cassette

$3.00 wafer

$3.20 disk

Let's face it. Cassette players were not designed to store digital data and programs. Tfiat's why we designed a digital storage system using a continuous tape loop: tfie Exatron Stringy/Floppy (ES/F) and the Wafer. There's no expensive interface to buy—the ES/F comes ready to pump up your TRS-80.*

Once your TRS-SC* is pumped up by our ES/F... you won't want to deflate it. We're so sure, that we offer an unconditional 30-day money-back guarantee and a one-year limited warranty. Over 2.000 TRS-80* owners have met the wafer... why don't you? '

EXATRON'S STRINGY/F

SPEED, CAPACITY AND RELIABILITY FOR ONLY $249.50

» CALL

OUR HOTLINE (800)-538-8559

IN CALIFORNIA. CALL(408)-737-7111

•TRS-80 Is a registered trademarK of Tandy Corp.

exatron, inc.

181 Commercial Street Sunnyvale. Calif. 94086

PKINTERS

ANADEX DP-9500 W/2K DUFFER 1375

ANADEX DP-9501 W/2K DUFFER 1450

DASE 2 600-D 599

C. ITOH 5TARWRITER 25 CPS 1750

C. ITOH 5TARWRITER 45 CPS 2450

A. CENTRONICS 737 625

EPSON MX-70 W/GRAPH1C5 449

D. EPSON MX-80 132 col 620

PAPER TIGER IDS-445 W/DOT PLOT 749

C. PAPER TIGER IDS-460 W/DOT PLOT 1195

PAPER TIGER IDS-560 W/DOT PLOT 1495

D. QUME SPRINT 5/45 2550

5ILENTYPE W/INTERFACE 549

SYSTEMS

A. APPLE II PLUS 16K 1049

APPLE II PLUS 48K (APPLE Memory) 11 89

APPLE II STANDARD MODELS CALL

These ore the newest models with FCC type opprovol to prevent RF interference.

D. DISK II DRIVE & CONTROLLER 529

This model includes DOS 3.0 16 sector

DISK II DRIVE ONLY (ADD-ON) 445

C. CHALLENGER 4P by OHIO SCIENTIFIC 699

C4PMF (MINI FLOPPY SYSTEM) 1599

CIP MODEL II 449

SARGON II (DISK OR CASSEHE) 35

FIG FORTH (DISK ONLY) 69

D. PMC-80 THE TRS-80 WORKALIKE' 629

16K LEVEL II W/PROGRAM RECORDER

CALL OR WRITE FOR MORE INFORAAATION

E. EXIDY SORCERER II CALL

AVAILADLE IN 16K, 32K & 48K MODELS

S-100 EXPANSION UNIT 075

WORD PROCESSING PAC 179

DEVELOPMENT PAC 69

F. ATARI 800 16K 799

ATARI 400 16K 499

810 DISK DRIVE 499

410 PROGRAM RECORDER 69

850 INTERFACE MODULE 175

o,

VIDEO MONITORS

A. AMDEX/LEEDEX VIDEO-100 12 • D&W 139

HITACHI 10" COLOR 389

D. NEC 12" P01 GREEN PHOSPHER CALL

PANACOLOR 10" COLOR 375

SANYO 9" D&W 179

C. SANYO 12" D&W 255

SANYO 12" P31 GREEN PHOSPHER 295

SANYO 13" COLOR 445

SHOPPING MAIL OKDEK? GALL US TODAY!

We probobly hove whot your're looking for in stock ot on incredible price. Our company is on ouchorized dealer for soles ond service for Apple Computef, Atori and Ohio Scientific- If you receive o defective product from us we will repoir or reploce Cot our option) any product in wofronty. O.ur Service Center will repair all Apple Computer products, in or out of worronty, whether it was purchosed from us or onother deoler. (coll for more details)

PHONE ORDERS IN CALIFORNIA, ALASKA, HAWAII & FOREIGN (714)69a-00«8

SHIPPING INFORMATION OR OACKORDERS PLEASE CALL (714)698-0260

SEF^VICE CENTER AND FOR TECHNICAL INFORAAATION (714)460-6302

TELEX 695-000 ANS:BETA ATTN:CCMO

1(X) BYTE May 1981

TOLL FREE ORDER LINE

600-654-6654

APPLE HARDWARE Y APPLE SOFTWARE

TOP FIVE SELLERS

LANGUAGE SYSTEM W/PASCAL. . . . 425 SILENTYPE PRINTER W/INTERFACE. 549

HAYES MICROMODEM II 319

VIDEX VIDEOTERM 80 w/grophics. 335 Z-80 MICROSOFT CARD 299

APPLE COMPUTER INC.

DISK II DRIVE ONLY 445

INTEGER, OP, APPLESOFT II FIRMWARE CARD 155

GRAPHICS TABLET 649

PARALLEL PRINTER INTERFACE CARD 155

HI-SPEED SERIAL INTERFACE CARD 155

COMMUNICATIONS INTERFACE CARD 185

SMARTERM 80 COLUMN VIDEO CARD 335

MOUKTAIN COMPUTER INC.

MUSIC SYSTEM (16 Voices) 479

A/D + D/A INTERFACE 319

EXPANSION CHASSIS 555

INTROL/X-10 SYSTEM 249

CLOCK/CALENDAR CARD 239

SUPERTALKER 5D-200 249

ROMPLU5+ CARD 135

ROMWRITER CARD 155

CALIFORNIA COMPUTER SYSTEMS

CLOCK/CALENDAR MODULE 109

GPID IEEE-488 CARD 259

ASYNCHRONOUS SERIAL INTERFACE CARD 129

CENTRONICS PARALLEL INTERFACE CARD 99

We carry oil CCS hardware. Pleose call

MISC. APPLE HARDWARE

16K RAM UPGRADE (Apple, TRS-80. Exidy) 189

16K RAM CARD MICROSOFT 169

ACT NUMERIC KEYPAD (old or new kybrd) 115

ACT BAR CODE READER WAND 1 79

ALF 3 VOICE MUSIC CARD 229

ALF 9 VOICE MUSIC CARD 1 69

ALPHA 5YNTAURI KEYBOARD SYSTEM 1399

BIT 3 FULL VIEW 60 CARD 349

CAT NOVATION ACOUSTIC MODEM 169

CORVUS 10MB HARD DISK CALL

LAZER LOWER CASt PLuS 50

MICRO-SCI DISK DRIVES CALL

PAYMAR LOWER CASE (old or riew kybrd) 55

RADCOM AMATEUR RADIO INTERFACE CARD 169

SPEECHLINK 2000 HEURISTICS 229

5SM AlO SERIAL/PARALLEL CARD AGT 189

SUP-R-TERMINAL 60 COL, CARD 339

SVA 8 INCH FLOPPY DISK CONTROLLER 345

VER5AWRITER DIGITIZER PAD 229

VIDEX KEYBOARD ENHANCER 115

We stock much more thon lisced. Pleose coll.

APPLE COMPUTER INC.

DOS TOOLKIT 65

APPLEPLOT 60

TAX PLANNER 99

APPLE WRITER 65

APPLE POST 45

DOW JONES PORTFOLIO EVALUATOR 45

DOW JONES NEWS 6 QUOTES REPORTER 85

APPLE FORTRAN 165

APPLE PILOT 129

DOS 3,3 UPGRADE 49

MUSIC THEORY 45

THE CASHIER Retoil Mrigmnt & Inv 199

THE CONTROLLER Gen, Bus, Sys 519

MISC APPLICATIONS PACKAGES

VISICALC 125

DESKTOP PLAN II 169

CCA DATA MANAGMENT DMS 65

EA5YWRITER WORD PROCESSOR 225

EA5YMOVER MAIL SYSTEM 225

EASYMAILER LEHER WRITER 225

ASCII EXPRESS 65

MICROSOFT FORTRAN 185

MICROSOFT COBOL 695

MICROSOFT BASIC COMPILER 375

SUPER TEXT II 139

PROGRAMMA APPLE PIE 119

THE LANDLORD Apt Mngmnt pockoge 649

PEACHTREE BUSINESS SOFTWARE CALL

TAX PREPARER by HowordSoft 89

APPLEBUG ASSEM/DI5A5SM/EDITOR 75

3-D GRAPHICS By Bill Budge 53

SUPER FORTH 49

TOP TEN GAMES

APPLE GALAXIAN 23

FLIGHT SIMULATOR 34

THE WIZARD AND THE PRINCESS 32

COSMOS MISSION (SPACE INVADERS) 24

SARGON II CHESS 32

HI-RES FOOTBALL 39

COMPUTER QUARTERBACK 39

ADVENTURE BY MICROSOFT 27

PHANTOMS FIVE 39

REVERSAL (OTHELLO) 34

CALL OR WRITE FOR A COMPLETE SOFTWARE LIST

ORDERING INFORAAATION Phone Orders invited usmg VISA MASTERCARD AMERICAN EXPRESS DINERS CLUD CARTE DLANCHE or bank wire [ronsfer Credn cards subject to service charge 2% for VISA 0 MC b-o for AE DC 6 CD Moil Orders may ^end credn cord accouni number tincitde expirotion dote) coshiers or certified check money order or personal check (allow 10 days lo cleor) Please include a telephone number with oil orders Foreign orders (excluding Mihtory PQ s) Odd 10% for shipping all lunds must be m US dollors Shipping handling and insurance in U S odd 3% {minimum S4 00) Colifomio residents odd 6% soles tax We occepi COD s under S500 OEMs Institutions 6 Corporoiions please send for written quotation All equipment is subject to price change end ovailobility without nonce All equipment is new ond complete with monufacturer worroniy (usually 90 doysl We connoi guoroniee merchontibility o( ony products We ship most orders wtihm 2 days

WE ARE A MEMDER OF THE DETTER BUSINESS DUREAU AND THE CHAMBER OF COMMERCE SHOWROOM PRICES MAY DIFFER FROM MAIL ORDER PRICES. PLEASE SEND ORDERS TO:

CONSUMER COMPUTERS MAIL ORDER 6314 PARKWAY DRIVE, GROSSMONT SHOPPING CENTER NORTH LA MESA CALIF. 92041

Circle 102 on inquiry card.

BYTE May 1981 101

System Notes

Improve TRS-80 Disk Operation

Add an External Data Separator

(lb)

Photo 1: External data separator circuitry as installed in the Radio Shack TRS-80 Expansion Interface. Most of the integrated circuits can occupy the space intended for the RS-232 interface (photo la). Irreversible changes can be avoided by bending a few pins on the FD1771 to obtain the necessary signals (see the wires leading from the FD1771, under the red cable, in photo lb).

Ken Kline 3821 Penitencia Creek Rd San Jose CA 95132

When I first added a floppy-disk drive to my Radio Shack TRS-80 Model I computer, I was very disappointed in its operation. My records indicated that, on the average, 1 was getting an error for every four disk accesses. These errors were independent of the type of access (ie: they occurred while accessing programs, data files, utilities, and even the bootstrap loading routine). In desperation, I called the Tandy Corporation in Fort Worth, Texas, and was told to use a better grade of disk. I tried this and noticed an improvement (to one error in eight accesses), but the lack of reliability was intolerable.

Discussing my problem with owners of other home computer systems, I came to the conclusion that the FD1771-01 floppy-disk controller part was the culprit. Don't misunderstand, I am not downgrading the FD1771. If you have studied the specifications and application notes of the FD1771 as much as I have you will realize that it is quite a marvelous piece of silicon. However, quoting from Western Digital Corporation's FD1771-01 Application Notes (document Number A0104, page 2) "In order to maintain an error rate better than 1 in 10*, an external data separator is recommended."

The data separator that I finally ended up with is shown schematically in figure 1. It is a modification of one of the external data separators recommended by Western Digital (as

102 May 1981 © BYTE Publications Inc

Circle 48 on inquiry card.

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VIDEO DISPLAY

12 inch

80 ch X 25 line

80 ch X 20 line geieclable by Programming 40chx25line ' ^

40 ch X 20 line Color (8 colors)/Green Smooth Scrolling

• FUNCTION KEY

Programmable 10 Keys

• FLOPPY DISC

5 inch X 2 deck, 280 KB/deck Dual sided — Double density

• SUPER FUNCTION KEY

Programmable 10 Keys

• PRINTER

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80 ch/line, 40 ch/line Graphic Mode

Alphabets (capital/small), Numerics, Katakana

Various Symbols, Hiragana, Kanji Roll Paper/Sproket Paper 3 Copies

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Tel: 213-641-4588, Telex: 182379 bmcing i

System Notes

D Q ICl

74LS74 CLK

CLR

PR <

74LS04

IC2a r4L8175

CLK

_ 3 Q 0

IC2b 74LS175

IC2c 74LS175

10

74LS161

AT

LOAD Qd IC6

CLK

CLEAR EN P ENT

74LS04

IK

5V

-Ofdclk

IC4

74LS08

2MHz CLOCK

r

IK

-C>roDATA

m

POWER CONNECTIONS

NUMBER

TYPE

+ 5V

GND

1

74LS74

14

7

2

74LS175

16

8

3

74LS00

14

7

4

74LS08

14

7

S

74LS04

14

7

6

74LS161

16

8

Figure 1: 'External data separator circuitry. This design was developed from one recommended by Western Digital in an applications note for its FD1771. This circuit adds a power-on reset feature.

shown on page 5 of the same document). After adding the external data separator to my TRS-80, access errors virtually disappeared.

The data separator was constructed on an old printed-circuit board. It already had the voltage and ground connections run to all integratedcircuit-socket positions, and it had edge-card connections. The circuit board now resides in the compartment of the TRS-80 Expansion Interface reserved for the RS-232C interface or other extra circuitry (see photo 1).

This circuit varies from the one in the Western Digital application notes in the use of +5 V on some integrated circuit pins (through a 1 k-ohm pull-up resistor) and a resistor/capacitor network that provides a lag of about 45 ms on the 74LS161 counter's CLEAR input (IC6,

pin 1) to insure that it is cleared on

power-up.

In order not to make any irreversible changes in the printed-circuit board of the TRS-80 Expansion Interface, the three connections to the FD1771 floppy-disk controller can be made through a 3-pin length of a dip strip, a type of socket. Remove the 1771 from its socket and carefully bend pins 25, 26, and 27 out from their normal position. Then reinsert the 1771 into its socket and push the 3-pin dip strip onto the three pins sticking out.

Pin 25 must be connected to ground when using an external data separator (pin 25 is normally pulled up to +5 V for internal data separation). Pins 26 and 27 are the separated clock and data inputs to the 1771. The raw data from the disk drive to the external data separator is avail

able at pin 8 of integrated circuit Z32

in the Expansion Interface, and the 2 MHz clock signal is picked up at pin 3 of Z25.

All signals are sent to Expansion Interface connector Jl and are available on the internal expansion connector inside the additional circuitry compartment. Ground is available on pins 41 and 42 of that connector, and + 5 V is available on pins 39 and 40 (see the right edge of the second page of the Expansion Interface schematic, page 41, in the Radio Shack Expansion Interface manual).

I measured the current required to operate the external data separator (using LS-type integrated circuits) and believe that the 40 mA it draws is certainly less burden on the Expansion Interface power supply than the RS-232C interface that might use this position. ■

104 May 1981 © BYTE Publicatioiis Inc

Play with a full deck.

Introducing the RM 65 line of microcomputer

The RM 65 line gives you the options and flexibility to design precisely the microcomputer systems you need.

And you can do it quickly and economically. Because you're offered so many design alternatives.

Application software for the RM 65 line, for example, can be programmed in a number of languages: BASIC, P1765, FORTH and Assembly Language.

RM 65 uses a motherboard interconnect concept so any card will fit any slot.

You can choose either edge connector or Eurocard versions.

And a set of card cages allows a broad variety of packaging options.

Single Board Computer Module

R6502 CPU, 2K bytes static RAM, 16K bytes PROM/ROM capacity, an R6522 VIA and support circuitry on a single RM 65 module.

Memory Modules

'8K Static RAM

• 32K Dynamic RAM

• 16K PROMIROM Input/Output Modules

• GP I/O and Timer 'ACIA (RS232C)

Intelligent Peripheral Controller Modules

• IEEE-488 Bus Interface

• Floppy D/s/c Controller

• CRT Controller

Accessories

• 4 and 8-slot Card Cages

• Design Prototyping Module

• Extender Module

' Single-Card AIM 65 Adaptor

• Adaptor/Buffer Module

Rockwell. Your systems source.

Your functional system can be economically developed on the AIM 65 Advanced Interactive Microcomputer. At less than $500, AIM 65based on the high performance R6502 microprocessor —is the lowest cost development tool available for any board level system.

Rockwell stands ready with the system and application assistance your project requires. Call Rockwell for more literature. Or to schedule time at one of Rockwell's system development centers.

Rockwell International, Electronic Devices Division, RO. Box 3669, Anaheim, CA 92803. (800) 854-8099 (In California 800-422-4230).

Rockwell International

...where science gets down to business

Star Raiders

Gregg Williams, Senior Editor

What can you say about a game that takes your breath away? There are not enough superlatives to describe Star Raiders. Just as the VisiCalc software package from Personal Software has enticed many people into buying Apple II computers, I'm sure that the Star Raiders software cartridge from Atari Inc has sold its share of Atari 400 and 800 computers.

What is Star Raiders? It's a video arcade game

that isn't hungry for quarters. I first saw Star Raiders at the West Coast Computer Faire in May 1979, and in the two years that have passed since the first public viewing of the game, no one—I repeat, no one—has created either a home-computer game or a coin-operated video game that is better than Star Raiders. (This fact is even more surprising when you consider the speed with which new standards are set in this industry.)

For the people who haven't seen Star Raiders in action, I'll attempt a brief description. Star Raiders is

Why spend all those quarters on arcade games? With a microcomputer and a few weeks' worth of arcade money, you can enjoy at home microcomputer games that are just as good as (and sometimes identical to) the popular coin-operated video arcade games. BYTE's Arcade is an occasional feature that reviews the best of these fast-action games. If you would like to review or give an opinion of a favorite microcomputer game of this type, please write to: BYTE's Arcade Editor, FOB 372, Hancock NH 03449.

Photo 1: The view from the bridge of the Star Raiders ship during a hyperspace jump. A static photo cannot do justice to the excitement you feel as stars streak by prior to the jump.

loosely modeled on the "Star Trek"-type game that has been running on micro- and larger computers for the past eight years. You, as commander of a starship, must search out and destroy all enemy spaceships in the galaxy (which is subdivided into a rectangular array of units called "sectors"). Of course you have only a certain amount of energy, and when you fight an enemy ship that is in the sector you occupy, it can fight back and damage your ship.

Star Raiders is a descendant of this kind of game in the same way that the new pocket computers are descendants of a four-function mechanical adding machine. The many innovations in Star Raiders make you feel that you are actually piloting the spaceship instead of just typing in commands (and endlessly pressing the ubiquitous RETURN key).

Star Raiders has color, sound, and joystick input to make the game more realistic, but the feature that gives it life is its real-time animation. When you patrol a sector, you see a field of stars passing you in all directions, as if you were actually moving through a three-dimensional field of stars. When you steer the ship using your joystick, the stars outside your ship veer realistically in the opposite direction. Enemy ships (called Zylons) appear from above or below, receding in size as they speed past. A battle claxon sounds when you enter a sector containing enemy ships. Attacking Zylons shoot balls of energy at your ship; if they hit, your shields flicker and you hear a destructive crash. And the hyperspace effect (used to

106 May 1981 © BYTE Publications Inc

ascal-l helps our customers meet complex, real-time

needs:

Don Cutler, Chief Systems Engineer,

Electro Scientific Industries, Inc. (ESI), Portlnnd, Oregon

More than 125,000 microcircuit resistors per hour can be adjusted by ESI's PDP-liy04 controlled laser trimming systems. The Pascal-1 compiler has given ESI fast, precise control since 1976. ESI's Don Cutler says, "Pascal-1 offers two big advantages— real-time performance and real problem-solving power."

Precise control in milliseconds.

Controlling a laser beam 4 to 8 microns in diameter, the ESI system moves the laser beam positioner at accelerations up to 3.5 G's, directs a trim cut, and decides where to go next, fast enough to trim 35 resistors per second. The Pascal-1 programs directly conh'ol all aspects of the trimming system. Some ESI customers use the laser trimmer to adjust the circuits of such devices as air flow transducers, audio filters.

Left: Pascal-1 controls ESI's laser trimming system. The laser repairs semiconductor memory chips, replacing faulty cells with alternates.

Below: ESI dominates the industry in the computer-controlled laser adjustment of microcircuits. Pascal-1 programming flexibility gives ESI access to many different markets.

and heart pacers, with the tTiicrodrcuit activated to simulate operation. Pascal-1 handles these processes with speed and precision.

Easy-to-follow programming.

Writing correct code is easy because of the logical structure and clarity of

gmeers save design and debugging time by writing control software in Pascal-1. ESI's customers also apply Pascal-1 to their own specialized production processes.

Oregon Software

2340 Southwest Canyon Road Portland, Oregon 97201 (503) 226-7760 • TWX 910-454-4779

Free case study.

Read why ESI, one of Oregon Software's 1700 customers, chose Pascal-1. Order your free copy of this eight-page case study by calling Oregon Software collect at (503) 226-7760 or by using the reader service card.

DISTRIBUTORS: Australia: Network Computer Services, Sydney/Tel: 290-3677 England: Real Time Products, London/Tel: 01-588-0667 Holland: N.H.C.S., B.V., Haarlem/Tel: 023-234951 Japan: Rikei Corporation, Tokyo/Tel: 345-1411 West Germany: AC Copy, Aachen/Tel: 0241-506096 West Germany: Periphere Computer Systems GmbH, Munchen/Tel: 089-681021

Circle 303 on inquiry card.

BYTE May 1981 107

Photo 2: The Star Raiders Galactic Chart, Each square represents a sector of space. The star symbols represent sectors containing starhases; all other squares marked with symbols represent sectors containing Zylon enemy ships. Your ship is located in the square near the center, marked by a small dot.

Photo 3: The view from the bridge during combat. "Star Trek" games were never like this! When you occupy the same sector as enemy ships (here, top and bottom center) their size will increase and decrease as you move toward or away from them.

Aha nianrp

Name

Author

Star Raiders

Doug Neubauer

Type

Format

Arcade-style game

Game cartridge

Manufacturer

Language

/\Lari inc

6502 machine language

Consumer Division

1195 Borregas Ave

Computer

Sunnyvale CA 94086

Atari 400 or 800

(408) 745-2000

Documentation

Price

10 pages, 22 by 28 cm

$59.95

(8V2 by 11 inches)

move you from one sector to another) must be seen to be believed!

I could continue to describe the intricacies of Star Raiders, but words cannot evoke the sensation of actually playing the game. To Doug Neubauer of Atari, who wrote Star Raiders, my unbounded thanks. To all software vendors, this is the game you have to surpass to get our attention. And to Atari, I can only say that if you offer us games like this, we can't refuse. ■

Super Nova

Bob Liddil, POB 66, Peterborough NH 03458

Arcade video games are extremely popular throughout the world. It would seem natural, therefore, that these games would take hold in the TRS-80 marketplace, where good graphics programs are in short supply. There is, to be sure, a good deal of mediocrity on the market, such as

early versions of Space Invaders. Super Nova, however, is an example of how well a program can be created if its designer takes enough time and care with it.

The instant the program (a standard machine-language system tape) is loaded. Super Nova spins into a stunning

108 May 1981 © BYTE Publications Inc

Circle 41 on inquiry card.

INTRODUCING R RCVOLUTIONRRV

DOTAARTRIXPRINTCR miTH JUST ON€ Hfl/VU\A€R. I RT RN iNCR€DIBl6 PRIC6

JUST $399. fl

The Uni-Hommer Replaces Seven... or More.

Revolutionary? We don't know what else to call it An impact printer with a single rugged hammer, rather than the seven or more individual solenoids and print wires found in conventional dot matrix printers.

At an incredible unit price of $399!

Because of the unique Uni-Hammer design, the GP-80M is smaller and simpler than other dot matrix printers yet costs considerably less. Which makes it a natural for OEMs needing compact, reliable, low cost printers for system use, and also for the personal or small business user who wants a quality impact printer at the lowest possible price.

Houj the Uni-Hammer UUorks

The GP-80M, which prints both graphics and aiphanumerics, uses a rotating platen with protruding splines positioned behind the paper (see diagram). The character or graphics image is created by multiple hammer strikes in rapid succession as the print head advances across the paper The precision gear train assures exact positioning of the print hammer relative to the splines on the platen, to provide excellent print quality.

fl Complete Printer

The GP-80M has features comparable to printers selling for thousands of dollars. These include upper/ lower ASCII character sets, ribbon cartridge, 80 columns at 12 characters per inch, adjustable tractor feed, original and 2 copies, 30 characters per second, and full graphics with a resolution of better than 60 dots per inch in both horizontal and vertical axes.

Plenty of Interfaces

Interfaces include Centronics parallel, RS232C, serial TTL, 20mA current loop, IEEE-488, Apple, TRS-80, PET, HP-85...and more.

See the GP-80M in action at your local computer store, or write for the distributor in your area.

fl Product of the Seiko Group

The GP-80M is manufactured by Seikosha and exclusively distributed in the USA by Axiom. It took a company such as the Seiko group, world's largest watch manufacturer, with vast experience in the design of small, intricate, precision products, to come up with a totally new concept in dot matrix printing.

AXIOM CORPORATION

1014 Griswold Avenue • San Fernando, CA 91340 Telephone: (213) 365-9521 -TWX: 910-496-1746

Photo 1: The Super Nova g(fme in play.

three-dimensional starburst display that looks so real it

makes you dizzy. The depth of field is absolutely startling. This is the most striking high-speed animation 1 have ever seen (with the possible exception of the hyperdrive display of Atari's Star Raiders. The graphics work in Super Nova is fast, stunning, and very uncharacteristic of TRS-80 games.

As with its coin-operated counterpart, Atari's Asteroids game, the object of Super Nova is to destroy objects that appear on the screen while avoiding your own destruction. Meteors, of all shapes and sizes, make up the bulk of these targets. When you hit the larger asteroids, they shatter into smaller and smaller chunks, and, if you're lucky or skillful, they finally disintegrate. It should be noted that the supply of meteors is unlimited.

Not content to menace the player with mere rocks hurtling through the void. Super Nova thoughtfully provides missile-firing alien spaceships. Three less-dangerous craft appear when there are six or less meteors on the screen. Two larger ships, worth more as targets, appear when you reach a score of 10,000 points.

Some of the aliens have special shields that allow them to pass harmlessly through meteors. Not so for your fighter—touch something, anything, and you're destroyed. The game ends when you have lost three ships.

Super Nova has a well-thought-out keyboard setup that enhances the playability of the game. Five keys control your ship's action in a fashion similar to the buttons supplied in coin-operated video games. The R and T keys turn the ship counterclockwise and clockwise, respectively. The O key applies engine thrust in whatever direction the ship is pointing, and the P key fires your missiles. Finally, the space bar launches the ship into hyperspace. The keys are located so that you play the game with the first two fingers of each hand touching the keys and

110 May 1981 © BYTE Publications Inc

Name

Format

Super Nova

Cassette

Language

Type

Z80 machine code

Arcade-style game

Computer

Manufacturer

TRS-80 Model I with

Big Five Software

16 K bytes of memory

FOB 9078-185

and Level I or Level II

Van Nuys CA 91409

BASIC

Price

Documentation

$14.95

1-page insert sheet

either thumb working the space bar.

Super Nova would be an enjoyable game if it had only the features I've described so far, but it offers even more. This game has refinements that distinguish a truly great computer game from a good one. The propulsion formula used to control the behavior of your ship, for example, is Newtonian in nature, closely simulating the actual response you would expect from a real spaceship. Going too fast or too far? Turn your ship in the opposite direction and increase thrust just enough—remember, opposite thrusts cancel each other out—and your ship stops.

The rotation controls (the R and T keys) turn the ship

in 45° increments, which is the best you can do with the limited TRS-80 graphics. As a last resort, hitting the space bar throws your ship into hyperspace. So if three large meteors and an enemy ship are converging on you from different directions, this action might save you. I say might because a hyperspace jump ends with your ship popping up anywhere on the screen. Since there are obstacles everywhere, you may find yourself in a worse position than when you started.

Game programs that cross my desk receive many a trial, but none is so grave or deadly as 12-year-old Richard's, my young neighbor and resident computergame buff. With his attention span of less than 5 minutes, he rips through normal TRS-80 games with uncarmy speed. His response to Super Nova, however, was an enthusiastic "Excellent!" He stayed with it for 3 hours, until his mother appeared to drag him away for homework. There is no higher recommendation available.

In summation. Super Nova is fast, entertaining, and professional. It is well worth its $14.95 price tag. I fully agree with Richard—Super Nova is excellent I ■

Circle 122 on inquiry card.

The next

generation L of business

TM

software

If you are still searching for quality software for your small business computer, search no more. Designer Software" is pleased to announce PHOENIX™, the first line of microcomputer software to include professional word processing and general accounting.

WORD PROCESSING We Itnow word processing. A year-and-a-half ago the owners of Designer Software" wrote a well-known word processor for another company. In the last 18 months we've learned about other features you want in a word processing package. PHOENIX" Word Processing reflects our experience. It is more powerful and flexible than other word processing packages you can buy. And since we designed "human engineering" into PHOENIX" Word Processing from the beginning, it can compete, feature for feature, with expensive dedicated word processors. Many people hove remarked that the user's manual we wrote earlier was the best ever for microcomputer software. Even so, we felt that we could have made it more accessible to the nontechnical user. With PHOENIX" Word Processing we hove a separate Training Manual with beginning, intermediate and advanced levels. By allowing you to work at your own level, we have made the learning process easier and less intimidating. ACCOUNTING

All five PHOENIX" general accounting packages (General Ledger, Accounts Receivoble arfd Payable, Payroll and Inventory) were designed by CPA's based on similar packages from mini and mainframe computers. The programs are COBOL with an integral

assembly-language data base. They are fully integrated to allow automated posting to the General Ledger. An internal screen handler permits full-screen data entry for speed and ease of use. Although we made cosmetic enhancements prior to distribution, the basic programs have been user-tested for at least eighteen months.

PHOENIX" Accounting also includes a growing number of specific application packages. We have completed or scheduled for completion Fixed Assets, Tenant Processing, Mail Management, Financial Projections and Time/Billing. Each package stands alone, but many also work in conjunction with other PHOENIX" packages. For example, PHOENIX" Mail Management will work very well by itself, but we also designed it to fit in easily with the merging capabilities of PHOENIX" Word Processing.

With PHOENIX" Accounting we have, as always, given special attention to documentation. Not being content to describe which buttons to push, we have taken the time to explain the accounting principles behind the programs and how each package fits into an automated office. To this end we created the fictional town of Smallville with a fictional company, Moustache Manufacturing. By seeing how Mr. Small and his employees use PHOENIX" Accounting at 2M, you learn to apply it to your office as well. The Smallville sections are amusing as well as informative, and you will likely read the manual just to find out what Sidney, Mr. Small's incompetent brother-in-law, will do next.

3400 Montrose Blvcl • Suite 718 • Houston, Texas 77006 (713) 520-8221 • Telex 790510 • Source TCU671

Designer Software and PHOENIX are trademarks of Palantir, Inc.

Pcsigocr Software™

HOUSTON

Tranquility Base

Robin Moore, Warner HiU Rd, RFD 5, Derry NH 03038

Photo 1: The Tranquility Base game in progress.

Bill Budge has written a lunar-lander-style arcade game for the Apple II. Called Tranquility Base, the game uses Apple high-resolution graphics to portray the lunarlander module and the moonscape below. The player attempts to bring the lunar module out of orbit and land it safely on one of several flat areas on the lunar surface. A fixed amount of fuel is provided, and the score is based on the number and quality of successful landings.

Playing the Game

The game is simple, although not necessarily easy to play. A key is pressed to start the action, and the lunarlander module appears, orbiting from left to right over a detailed moonscape. The rockets are controlled with the Apple II's game paddle 0, while the "1" and "2" keys on the keyboard adjust the rotational attitude of the lander. Each keypress rotates the ship slightly in one direction or the other. There are no steering rockets, so'the lander's horizontal motion must be controlled by rotating the ship and using the main rockets.

It is difficult to make a successful landing. The landing areas are never much larger than the width of the ship, and the rocket control is quite sensitive, so you might cause the ship to take off just as you are gently touching down. If the lunar module touches anything except a flat landing area, it crashes and explodes. Landing too quickly can also cause a crash and an explosion. The score for each successful landing is derived from the horizontal and vertical velocities of the ship when it touches down,

Graphics and Sound

Consistently excellent graphics are a hallmark of Bill Budge's games, and the Tranquility Base graphics are no exception. From the title display that shows the lunar module, moonscape, and starfield (with little apples as planets) to the final module explosion, the graphics are great. The lunar module is nicely detailed, and when it explodes, pieces fly off and tumble in various directions. Even the rocket flame is detailed: it flickers realistically and provides visual feedback by smoothly changing size as the rocket thrust is varied.

When the lunar module orbits off the right edge of the screen, a new section of scenery snaps into view below, and the lander orbits in from the left. Tranquility Base also provides a close-up view of the lander and the moonscape when the lander is a certain distance from the ground: this will help you make a smooth landing. Fuel

112

May 1981 ® BYTE Publicatioiis Inc

Circle 437 on Inquiry card.

Circle 56 on Inquiry card.

EXTRA. EXTRA.

Extra paper widths Extra alphabet selection —

o

Now you get more extras when you pick the new dot matrix printers by C. Itoh. Choose the Comet 80-coiumn printer and get the extra benefits of four character sizes and paper-saving print compression. Choose the Comet I! 136-coIumn printer and receive the added extra of a fuU-width computer size printer that accommodates paper widths to 381 mm (15").

Both the Comet and Comet II also offer the rare combination of low cost and high performance. Both models operate at an efficient 125 cps bidirectional print speed and in a 9 x 7 dot matrix.

C. Itoh's Comet series has the extra advantage of a unique multilingual capability with a selection of four, different alphabets: English, German, Japanese and Swedish. Other special characteristics include a programmable VFU (Vertical Format Unit) plus

self-test diagnostics. For your operator's convenience, there's easy bottom or back paper loading, and both Comets use a standard low-cost nylon ribbon. Plus our printers already meet 1981 Class A FCC, UL, and fire safety requirements.

If all that wasn't enough. Comet and Comet II are plug-compatible vinth all major printers in the industry, meeting standard parallel serial interface specifications. Our printers are backed by C. Itoh's warranty and a nationwide field sendee organization.

And as a final, all important extra, when you choose either printer from C. Itoh you get immediate off-the-shelf delivery

So if you vvanf the highest quality at the best price, look into the extras the C. Itoh Comet and Comet II printers offer. You'll get a lot more than you bargained for. For more information, contact C. Itoh Electronics, Inc., 5301 Beethoven Street, Los Angeles, CA 90066; Tel. (213) 306-6700. Chicago Ofiice: 240 E. Lake Street, Suite 301-A, Addison, IL 60101; Tel. (312) 941-1310, New York Office: 666 Third Ave., NY, NY 10017; Tel. (212) 682-0420. Dallas Ofiice: 17060 Dallas Pkwy., No. 108, TX 75248; Tel. (214) 931-0177 C. Itoh represented in Canada by Canadian General Hectric.

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level, horizontal and vertical velocities, and altitude are displayed in text form below the graphics display. This aspect might have been improved by using analog dis

Name

Tranquility Base

Format

oy4~inc£i noppy uisk

Type

Arcade-style game

Language

6502 machine language

Manufacturer

Stoneware

50 Belvedere

San Rafael CA 94901

Computer

Apple II or Apple II

Plus with one disk and 32 K bytes of memory

Price $24.95

Documentation Instructions in game

Author

Bill Budge

plays simulated with graphics.

Most arcade-type games make extensive use of sound effects to enhance the realism of the simulation. Unfortunately, Tranquility Base takes little advantage of the Apple U's sound capabilities. Sound is used when the lander crashes and explodes, but it is not very realistic. I would have preferred some rocket-motor sounds varying with the thrust level, and perhaps a warning tone to indicate unsafe landing parameters.

Conclusions

• Tranquility Base is a medium-speed lunar-landerstyle arcade game with excellent graphics. Like most of Bill Budge's games, it is well done and functions flawless

ly.

•The game is fairly difficult to play, enough so that it

tends to discourage some new users. After a little practice, however, it becomes more enjoyable and exciting.

• Whether or not Tranquility Base is worth $25 depends on how much you enjoy the game and how often you play. I suggest that you try it out at a local computer store before you make a decision. ■

To Place An Order

From Outside Texas 1-800-231-3680

Questions & Answers

& Orders Texas 1-713-392-0747

■MARYMAC INDUSTRIES, INC."

store ifG-l 89 AUTHORIZED SALES CENTER

BRAND NEW IN CARTONS DELIVERED. Maiymac Industries owns & operates Radio Shack* dealership in Katy, Texas. Warranties will be honored by all company owned Radio Shack* stores, & participating franchisees and dealer authorized sales centers. Save State Sales Tax. Texas Residents Add Only S7t Sales Tax. Open Mon.-Sat. 9-6. We pay freight and insurance. No extra charge for Master Charge & Visa. Call us for reference in or near your city. Ref: Farmers State Bulk, Brookshire, Texas. Write or visit us at,

21969 Katy Fwy, Katy (Houston), Texas 77450.

WE OFFER ON REQUEST

Fadaril Express

Hausten Intarcontinsntal Airport Daiivary

U.P.S.BLUE

Raferencas from people who have bought computers from us probably in your city

ED McMANUS

0

B

0

10% 15%

OR MORE

Model III

In stock TR8-80 Modal 11 and ill

No Tax on Out of Texas Shipmsntsl

WE ALWAYS OFFER

0 NO extra charga far Mistar Cliarga or Visa

0 Wa always pay the freight and insurance

0 Tail free order number

0 Our capability to ge to the giant Tandy Computer warehouse S hours away, in Ft Worth, Taxes, to keep yaii in stock.

JOE McMANUS

In Stock

114 May 1981 © BYTE Publicatioiu Inc

Circle 229 on inquiry card.

APPLE • ARMCO ' ATARI • BANK OF LOUISVILLE

• BAYLOR UNIVERSIW • BEOHTEL • BELL TELEPHONE

• BOEING • BORDEN • B^E MAGAZINE • OAUFORNIA DD.E, • OENTRONICS • OHASE MANHATTAN BANK

• OOMPUSHOP • OONSUMERCOMPUTER MARKET ING • OOX GABLE W/SPOKANE • DUKE UNIVERSI?/ MEDICAL GENTER • EASTMAN KODAK • GEN RAD

• HARRIS SEMICCNDUCTGR • HARVARD UNIVERSIW HBM • 1^ SEMICONDUCTOR • JONES & D\UCHL

STEEL • LOYOD\

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MIGHIGAN STATE UNIVERSIW- MO ARE • NATIONAL EYE RESEARGH FOUNDATIO

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Hardheaded Software.

The folks on this list are not exactly impulse buyers. In fact, before they buy anything it's usually subjected to painstaking research and evaluation. Each one chose software fronn High Technology.

In less than thirty minutes your dealer can show you why our software would be just right for you, too. To see the infinite variety of applications for your Apple II*, from inventory control to education, ask for a demonstration today

High Technology Software Products, Inc., P.O. Box B-14665, 8001 Classen Boulevard, Oklahoma Oity, Oklahoma 73113 [405) 840-9900

High Technology

Circle 184 on inquiry card.

"Indicates trademark of Apple Computer. Inc

BYTE May 1981 115

Asteroids in Space and Planetoids

Oliver Holt Old Nashua Rd Amherst NH 03031

Photo 1: Asteroids in Space is the title of the Asteroids game for the Apple from Quality Software. It is similar to the actual arcade game; the spaceship is controlled via the game paddles.

M

O

O

Photo 2: Planetoids is Adventure International's offering. The use of machine-language programming combined with highresolution graphics results in smooth action without a jittery picture.

Asteroids by Atari Inc is certainly one of the most popular arcade games in this country, inspiring people of all ages to deposit their quarters with devotion. Due to this popularity, it was only a matter of time before a home-computer version was developed. Asteroids in Space (by Quality Software, referred to as QS) and Planetoids (by Adventure International, or AI) both closely simulate the Atari game, in which a player must destroy asteroids and alien ships by accurately firing a laser. An off-target laser shot or slow response is fatal. The Apple's high-resolution graphics capabihties allowed the authors to reproduce almost exactly the display features of the original game. Both games skillfully employ realistic sound effects. The two versions use game paddles to control the motion of a spaceship and to fire lasers, but because of differences in the method of control used each game has a unique feel.

Planetoids

On start-up. Planetoids (from AI) displays a menu that includes several levels of play. This menu is part of a HELLO disk program written in both Integer and Applesoft BASIC, allowing use in either an Apple II or an Apple II Plus. The options in this menu give a choice of easy, regular, or hard modes of play, as well as a demo mode to display how the game works.

In the easy mode everything on the screen is very explosive. Every planetoid particle has the potential to destroy your spaceship unless your laser beam gets to the particle first. (Points are based on the number of planetoids you destroy.) The regular mode is supposed to be an emulation of the actual arcade game, but it does not appear to be significantly different from the easy mode. In the hard mode, the planetoids behave differently; they migrate toward your ship as if pulled by gravity. This characteristic becomes particularly annoying when one of your ships is destroyed and you still have other ships left to play. At this point, the planetoids gather around

116 May 1981 © BYTE Publications Inc

Arm Yourself With Pascal/IVIT+®

NOW! THE PACKAGE INCLUDES OUR EXCLUSIVE PASCAL ORIENTED SCREEN EDITOR.

You know what a monster a deadline can be if you have to face it without the proper tools. Arm yourself with an integrated set of programs, designed from the beginning for production use, all tuned to the single goal of producing reliable software. Pascal/IVIT+ is a fully integrated program production system including our compiler, debugger, disassembler and linker.

Used by many companies, large and small, Pascal/MT+ produces high quality reliable products in an amazingly short amount of time. Our run-time library contains all the tools needed to begin program construction immediately. Pascal/MT+ produces efficient, small native machine code demanded by today's product developers. All of our library routines and features work exactly the same on 16-bit systems as they do on 8-bit systems so you can increase your capability without rewriting any of your software. Your production quality products demand production quality tools. Order Pascal/iyiT+ now, call us today!

Payment Terms:

Cash, Check, UPS, C.O.D., Mastercard, VISA, Company P.O.

Pascal/IVIT+ Features:

An International Standard:

Pascal/MT+ conforms to the ISO Standard for Pascal, our competition doesn't even come close! A report on the performance of Pascal/iVIT+ on the Pascal validation suite is included with each compiler.

Modular Program Compilation:

The Pascal/IVIT+ modular compilation mechanism allows construction of fully coupled modules and programs allowing the modularization of large programs without any sacrifice in either space or time efficiency.

Efficient Native Code:

All versions of Pascal/MT+ produce efficient, compact NATIVE OBJECT CODE. In an independent benchmark Pascal/IVIT+ outperformed all other Pascal compilers on our target machines. In addition it produced the smallest final programs by including only the minimum run-time overhead necessary.

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Totally Portable:

Pascal/!VIT+ has been designed from the beginning to generate code for many different microprocessors. Pascal/IVIT+ programs you create today can be re-compiled to run on a more powerful machine tomorrow. All of the extended language features are present in every version of the compiler. This means you won't have to start over when the customer demands more, more and more.

Extensions:

Pascal/MT+ has many extensions to the Pascal language too numerous to describe in detail here. Our 160 page user's guide describes the features and gives examples of how to use them. A short summary of features is listed below: dynamic strings, BCD and Floating point reals. AIV1D9511 support, bit, byte and unsigned word manipulation, I/O port access, afull implementation of the NEW and DISPOSE heap and many others.

Target Machines:

Available now , . 8080, 8085 and Z80

Available soon 8086,

Requires CP/M or CP/M86

Pricing:

8080/Z80—$475.00 Others Call

CoFnmunication Arts. HuntinQion Beach. CA

Name

Language

PI an ptni A <s

6502 machine lancuaffe

(has menu programs in

Type of package

both Integer and

Arcade-style game

Applesoft BASIC)

Manufacturer

Computer needed

Adventure

Apple 11 or Apple 11

International

Plus with 48 K bytes

POB 3435

of memory and one

Longwood FL 32750

floppy-disk

Price

Documentation

$19.95

One page with descrip

tion of the game; addi

Format

tional instructions in

5Vi-inch floppy disk

the actual program.

HEATH

OWNERS

UPGRADE your H9 lor a (roc lion of the cost of g new terminal with these features.

FLICKER FREE

)l Columbus would have hai

$69.95 KIT $79.95 ASSEMBLED )il tor his H9 oporallng at 600 baud, he might not have discouvered America. Al last your computer can communlcale with your H9 eight llmsB faster (4B00 baud) without that annoying retreoh inlerrupt that causes the screen to flash at rales greater than 600 baud. Faster llatinQB. Fatter program exeoutlon. Eight times faster.

CURSOR CONTROL $a9.S5 KIT S34.95 ASSEMBLED

Why Nmil your output to coftBceutlv* lines of your terminal? CURSOR CONTROL allows your compular to move tlw cursor anywiiere on lha screan. Add that protessionsi touch 10 your displays by utlllztng masking technlquas. Functions Included are; left, ftgh\. up. down, lati and rfglit 20 apaeos, home and erase page,

GRAFIX $59.85 KIT S60.95 ASSEMBLED

Open a whole now world to your output. The graphical display capaliiliUas of QRAFiX allow you to create displays never before possible on the H8.

LOWER CASE ENTRY S2e.S8 ASSEMBLED

Now you can enter lower case characters from the keyboard. A Shift Lock key allows the keyboard to operate as the standard H9 keybosrd Or to generate upper and lower Case doponding upon Ihe Shitt key as per a normal lypaw.rilor.

LOWER CASE DISPLAY S34.77 ASSEMBLED

Lower case capabilllies greatly Improvo readability on terminals modified for 24 linos.

S12.S0SET 4 ARROWS $1.00 erics. For thai professional reel.

KEY CAPS

These qu.iiiry contour key caps have molded-lh ale

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the spot where your next ship will appear, making it difficult to escape without being destroyed. Sometimes your spaceship will reappear directly under a planetoid and explode before you even realize that your ship has (momentarily) returned. When this happens you have no choice but to sit there and watch your spaceships dwindle away with no hope of retaliation.

Planetoids uses one paddle and the keyboard to control the ship. You rotate the paddle to turn the spaceship and press the paddle button to apply thrust. The spaceship will continue to move in the direction it is pointed as long as the button is depressed, but it stops as soon as the button is released. Pressing any key on the keyboard fires a laser in the direction the ship is pointing. However, there is no provision for putting the ship into hyperspace, as in the original coin-operated version.

Asteroids in Space

Quality Software's Asteroids in Space has two choices on start-up, offering either a normal or demo game. When in demo mode, the spaceship randomly moves around in space shooting the laser beam in all directions until the ship itself is destroyed. Watching this can be useful if you have never played this kind of game before, but most users will want to go directly to the normal mode. This mode of play offers separate choices for either normal or fast lasers and asteroids. According to the documentation, higher scores may be obtained with either fast lasers or fast asteroids, or both. The game's difficulty increases, however.

Both game paddles are used to control the action in this version. One paddle controls the movement of the spaceship, rotating it by turning the paddle, and thrusting it by pushing the button. However, this game incorporates momentum into the action of the spaceship, requiring you to use the thrust to slow the ship or to change its direction of movement. [/ have trouble playing this version because I spend all my time trying to stop my ship from moving....GW\ Unlike the AI game, your ship can move in one direction while it fires in another. Lasers are fired using the game button on the other paddle. This method of control is harder to mentally and physically coordinate, making the game more challenging and frustrating. This game, like Planetoids, does not have the hyperspace feature of the original Atari version.

Scoring for both games is determined by the number of alien spaceships and asteroids (or planetoids) you can destroy. The QS version awards from twenty to thirty points for larger asteroids, more for smaller ones. Alien spaceships are worth up to 300 points. The AI game allows only ten points for the planetoids and up to fifty for the alien ships.

The graphics in both games are very good, very similar to the original arcade game. All the objects move

118 May 1981 © BYTE PubUcaUons Inc

Circle 285 on inquiry card.

Circle 250 on Inquiry card.

NEW DISK SYSTEM POUSHES APPLE^

Plug into your Apple II or Apple II-plus with a Micro-Sci disk system, and you get Apple software compatibility, PLUS: Increased capacity, improved performance and higher reliability. And you save money, too!

COMPAnBILIIY:

With thousands of programs currently available in Apple format—and many more being released every day—the ability to read and write diskettes interchangeable with the Apple disk II system is a MUST The Micro-Sci disk subsystems offer this compatibility and more, C>ur disk system has ajumper-sclectable boot PROM to move from DOS 3.2 to DOS 3.3, or to the language system at your fingertips.

CAPACITY:

The Micro-Sci A-40 system provides 40 tracks of storage (versus the Apple disk II system which offers only 35 tracks). The A-40's 5 extra tracks give you an additional 20,000 bytes of storage. And for even greater capacity, check out our A-70 system which offers a full 70 tracks of storage—exactly DOUBLE the storage capacity of the Apple disk II system!

PERFORMANCE:

Micro-Sci's disk systems' abbreviated track-to-track access time of Smsec (versus 15msec for the Apple disk II) means improved random disk access performance.

REUABIUTY:

Micro-Sci disk systems incorporate bemd-actuated head positioners for faster access and more accurate head positioning. Each disk system features Micro-Sci's improved media centering system which provides uncommonly accurate diskette registration, and virtually eliminates damage to the media centering hole.

PRICE:

The Micro-Sci A-40 drive, with controller, is priced at only $549; the second A-40 drive is only $449. The large-capacity A-70 disk drh^e with controller is only $699, with the second drive priced at only $599.

Call or write us today to order your new Micro-Sci disk system.

17742 Irvine Boulevard, Suite 205. Tustin, California 92680 / Phone: 714/731-9461 / Telex: 910-346-6739

Apple and Apple II are registered trademarks of APPLE COMPUTERS INC., SAN JOSE, CALIFORNIA

The PASCAL SERIES ByThe

Denver Software

Company...

A Breakthrough

In Software

Development.

PASCAL TUTOR™

A step-by-step introduction for learning the basic Pascal programming language. Presented in a simple format and logical order, the PASCAL TUTOR™ uses clear examples to ensure complete comprehension and progress for the beginning Pascal programmer.

The PASCAL TUTOR™ is a computer-paced course of study, that includes two diskettes and a comprehensive tutorial manual. The manual provides instructions and the computer verifies the work, enabling tfie user to learn basic Pascal syntax and structured programming as quickly and efficiently as possible.,

PASCAL PROGRAMMER™

Save time and concentrate your efforts on application design rather than detail programming. The Denver Software Company has designed pre-tested, ready-to-use programs and routines which drastically reduce the effort normally associated with coding, testing and debugging. The PASCAL PROGRAMMER™ is a collection of linked intrinsic modules written in UCSD Pascal* which gives you . a wide variety of functions that can be easily modified for specific applications.

Five categories of modules are supplied; General Utility (for direct interaction between user and application), Sorting and Searching, Disk File Access, Report and Display, and Disk Copying.

The PASCAL PROGRAMMER™ comes complete with a comprehensive user's manual containing source listings and examples, ideas and instructions for modifications and all needed operating instructions. .The included diskettes have demonstration and utility programs, source code, and ready-to-use library units.

Because complete program listings are included in the manual, the PASCAL PROGRAMMER™ can be applied to any Pascal-based computer and used with either diskettes or hard discs.

Suggested retail price, $90.

*UCSD Pascal is a trademark of the Regents of the University, of California.

THE DENVER SOFTWARE COMPANY

, MANUFACTURERS OF MICROCOMPUTER SOFTWARE .

i>5<

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Name

Language

Asteroids in Space

6502 machine language

Type of package

Computer needed

Arcade-style game

Apple II or Apple II

Plus with 48 K bytes

Manufacturer

of memory and one

Quality Software

floppy-disk drive

6660 Reseda Blvd

Suite 105

Documentation

Reseda CA 91335

One page with descrip

tion of the game; addi

Price

tional instructions in

$19.95

the actual program.

Format

5y4-inch floppy disk

smoothly without the annoying "jumping" or jitter effect predominant in lower-resolution video games and some of the poorer high-resolution graphics games. Sound effects were also similar to the arcade game, but I felt the QS version to be more realistic and of higher quality. The AI sounds were barely audible over the pounding of the keyboard while I was firing at objects on the screen.

Conclusions

Having played both games, I feel it's difficult to choose between them. The QS version offers different speed variations, while the AI version offers three levels of play. I like the AI version better because it can be slightly easier to play and there are three distinct variations to the game. The more astute game player might prefer the greater physical dexterity and mind/eye coordination required by the QS version. However, the games are different enough to entice most people to own both. ■

A Public Service of This Magazine & The Advertising Council iJ^H

Need help? Callus. -I

Red Cross counting on you.

120 May 1981 © BYTE Publications inc Circle 120 on inquiry card.

^Tinally...Space Technology Has Come Of Age, To The Benefit

Of Us Air

Products of

The Denver Software Company include: The FINANCIAL PARTNER'", an accounting system for small business and home use that features a self-teaching bookkeeping manual. The PASCAL TUTORS" and The PASCAL PROGRAMf^ER'". See details on facing page.

THE DENVER SOFTWARE COMPANY

MANUFACTURERS OF MICROCOMPU1ER SOFTWARE

36 Steele Street, Suite 10 • Denver, Colorado B0206 Dealer inquiries welcome, 303 331 -4661.

Circle 121 on Inquiry card.

Programming Quickies

Using Page Two with Apple Pascal Turtle Graphics

Bruce Wallace, 333 Escuela Ave #316, Mountain View CA 94040

So, you have Pascal up on your Apple and you're ready to use the built-in turtle graphics. One of the first things you probably notice is that the Pascal manuals never mention which high-resolution graphics page you are working with. In fact, the manuals don't even mention that a second page exists. Well, it does. And, it turns out to be fairly simple to use the unit TURTLEGRAPHICS on either page. There are three things to be considered:

1. reserving the page two memory space

2. getting TURTLEGRAPHICS to plot on page two

3. getting the Apple to display page two

Before we get into graphics, we'll need a technique for PEEKing and POKEing. This can be done with the help of the following declarations:

TYPE byte = 0. 255;

pab = PACKED ARRAY[0..1] OF byte; multitype = RECORD

CASE integer OF

1 : (int:integer);

2 : (ptr:tpab);

3 : (dptrt integer) END;

A variable declared to be of type "multitype" can be referred to as either an integer or a pointer variable. This leads to the following definitions:

PROCEDURE poke{acldr:lnteger; value:byte);

VAR locahmultitype;

BEGIN

local.int: = addr;

local.ptrl[0] := value END;

FUNOTION peek{addr:integer):byte;

VAR local:multltype;

BEGIN

local.int: = addr;

peek := local.ptrt[0] END;

Now that we can access memory directly, we need to reserve the memory space for high-resolution page two;

otherwise, Pascal might try and use it for stack or heap space. The UCSD extension routine RELEASE will do the trick for us. Assume that "save" is declared to be of type "multitype." The code segment:

save.int := 24576; release(save.dptr);

will reserve all of low memory up to address hexadecimal 6000 (24 K). This is done once at the beginning of your program.

Next, inform TURTLEGRAPHICS which page it is to use. Do this by placing a 2 or a non-2 value into a particular memory location for page-two or page-one plotting, respectively. A pointer to this location resides as the eighth entry in a pointer table. The table itself is pointed to by the contents of absolute locations 254 and 255 decimal. This leads to the following routine, which sets the page to be plotted on:

PROCEDURE setdraw(page1:boolean);

VAR local;multitype;

BEGIN

local.Int: = 254;

local.int: = local.dptrt +14;

IF page1 THEN local.dptrt := 1 ELSE local.dptrt : = 2

END;

Finally, we must be able to switch the page that Apple is displaying. After we are in the high-resolution mode via a call to GRAFMODE, we simply PEEK or POKE as we would in BASIC. Using the above PEEK or POKE routines, access —16299 or —16300 for page two or page one, respectively.

In general, INITTURTLE only works with page one, and, in fact, it even resets the display mode to page one. Use FILLSCREEN to clear page two. Also, the turtle position is not moved when changing the high-resolution page via "setdraw" above. For example, if you left off plotting at x,y position 50,50 with an angle of 45°, that's where you will start plotting on the other page.

Armed with these handy code segments, you can now get smooth animation by flipping from page to page. This should open up new possibilities for Apple Pascal graphics users. ■

122 May IWl © BYTE FttblkaUons Inc

Lifelines*

Tiie serious publication for the serious software user*

April 1981 Vol. 11ssue #11

I From the Software Evaluation Group: A thorough assessment of Condor*, A Database Manager.

BASIC Comparisons: Part of the SBASIC* Review.

A careful look at PMATE*, A New Text Editor.

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'Condor is a trademark of Condor Computer Corporation. "SBASIC is a trademark of Topaz Programming. 'PMATE is a trademark of Phoenix Software Associates, Ltd. 'CP/M is a trademark of Digital Ro^^fch. inc.

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BYTE May 1981 123

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POWER MODEM

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126 May 1981 © BYTE Publications Inc

Circle 45 on inquiry card.

Circle 117 on inquiry card.

dalosoulh announces.

THE TOTAL PRINTER MCKME!

With so many matrix printers on tlie marl<et today, it may seem tough to find exactly the right one for your application. Some models may offer the speed you need, others the communications flexibility and still others the forms handling capability. But no printer offers all the features you need...until now. The DS180 matrix printer provides the total package of performance features and reliability required for applications such as CRT slave copy remote terminal networks and small to mid-range systems. Not a "hobby-grade" printer, the DS180 is a real workhorse designed to handle your most demanding printer requirements. And pricing on the DS180 is hundreds of dollars below competitive units.

High Speed Printing—Bidirectional, logic-seeking printing at 180 cps offers throughput of over 200 Ipm on average text. A 9-wire printhead life-tested at 650 million characters generates a 9x7 matrix with true lower case descenders and underlining.

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and many other features may be programmed and stored from the keypad.When your system is powered down, the format is retained in memory. The DS180 even remembers the line where you stopped printing. There Is no need to reset the top of form, margins, baud rate, etc....It's all stored In the memory. If you need to reconfigure for another application, simply load a new format into the memory

Communications Versatility-The DS180 offers three interfaces including RS232, current loop and 8-bit parallel. Baud rates from 110-9600 may be selected. A IK buffer and X-on, X-off handshaking ensure optimum throughput.

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data©@Qj]GC^

computer corporation

4740 Dwight Evans Road • Charlotte, North Carolina 28210 • 704/523-8500

Washington Tackles the Software Problem

Christopher Kern 2011 St SW, Apt 839 Washington DC 20024

There was a time when a personal computer was nothing more than a microprocessor, some support circuits, a couple of thousand bytes of memory, and a few light-emitting diodes. In those bygone days, "software" consisted of a painstakingly crafted 1280-byte nano-BASIC interpreter, which was stored as perforations in a long, thin strand of paper and loaded into the machine by a device known, quaintly, as a papertape reader.

Today, all you have to do to get your new 16-bit, 8 MHz, 12 M byte, 512-by-512 pixel, hand-held color widget going is to break the cellophane. And as long as you haven't managed to clobber the widget's sophisticated mega-tasking, ultra-user operating system, or the various editors, high-level language compilers and interpreters, and powerful application programs that come as standard equipment, you are up and running.

All that fancy software is as much a part of the widget as the hardware that it runs on, and the attempt by the Widgetizer Corporation and others like it to protect their investment in

About the Author

Christopher Kern is a lawyer by trainitig, a journalist by trade, and a computer programmer just for the fun of it.

software development is the reason why the courts and Congress now find themselves confronted with the "software problem."

The Software Problem

The software problem actually existed before the advent of the microcomputer, but spectacular improvements in microcomputer hardware have increased the demand for sophisticated software. At the same time, reduced production costs for hardware have radically enlarged the computer market, making it increasingly difficult to control software piracy.

Most microcomputer products are based on one of a relatively small set of microprocessors, so it is technically as well as economically practical to copy software, moving it from one hardware environment to another. Within the hobby market, this typically takes the form of one hobbyist copying commercial programs for a few friends. At the least, this is probably a violation of the purchaser's contractual obligation to the software vendor; it is certainly the moral equivalent of larceny. But although this practice is obviously a serious matter for those who sell software to the home market, its relative economic significance is fairly small. The real problem is the commerical duplication—often entirely legal—of

software and software-based products for commercial purposes.

The Copyright Problem

When Congress overhauled the nation's copyright laws in 1976, it sidestepped the software problem by failing to specify the extent to which computer programs were eligible for copyright protection. A source listing clearly could be protected by copyright; a listing of a program is, after all, just a text. But what about the program as it appears in other forms? It was not clear whether object code, stored as a series of binary electronic impulses in memory or as magnetic fields on a mass storage device, was also subject to the creator's copyright.

One notorious illustration of the problem involved a microcomputer chess game sold by a Florida company called Data Cash Systems. The Data Cash game appeared on the market in 1977 and sold for $169. A year later, JS & A Group Inc of Chicago introduced a competitive chess game for $99. The program it used was identical to the one used in the Data Cash machine.

Although the two programs were unquestionably the same. Data Cash lost its copyright infringement suit on the grounds that the law, as it then existed, did not protect software in object-code form. The trial court rul

128 May 1981 © BYTE PublicaUons Inc

^^And in conclusion, FU only use my exceptional powers for the good of mankind."

"That's a vow all we Vector 3005s make. And it's not one we make lightly.

"After all, being the only product on the market with a Vector 3 terminal, a 5%" floppy, and a 5J<" Winchester rigid disk drive that provides 5 megabytes of storage is quite a responsibility. It used to take 20 floppies to give you that kind of capacity.

"Our powers don't stop there, however. Each 3005 also comes with a 32-bit error-correcting code —the first time sophisticated IBM-style technology has been available on a small business system.This lets us detect and correct errors, and almost completely eliminates data loss on disks due to dirt, wear, or damage. "All this makes us pretty awesome, all right. But there's more. When coupled with Vector's MEMORITE III and EXECUPLAN software packages, we give you a 30,000 word dictionary, the ability to create your own phrase library, a teaching manual right on the screen, pass word security, plus a host of other word processing capabilities as well as financial planning, forecasting and basic accounting.

"And we're reliable. Our powers won't diminish, our abilities won't fade, and dedication to mankind won't weaken.

"For more information and your nearest dealer, call Vector at 800-423-5857. In California, call 800-382-3367. Or write to them at 31364 Via Colinas, Westlake Village, CA 91362.

"Thank you all for coming today. And I hope we'll have the chance to do business together in the future!'

VECTOR GRAPHIC INC. COMPUTERS FOR THE ADVANCEMENT OF SOCIETY.

Circle 425 on inquiry card.

Supreme Court Takes a Softer Look at Software

"A claim drawn to subject matter otherwise statutory does not become nonstatutory simply because it uses a mathematical formula, computer program, or digital computer."

Justice William Rehnquist, Majority Decision, Diamond v. Diehr, March 1981

With this somewhat cryptic remark, the Supreme Court has, in the words of software and patent expert Morton C Jacobs, "removed the shackles from the software innovator." The Diamond v. Diehr decision (described in the accompanying article) was the culmination of years of court cases involving the patentability of software.

The key word in the above quote is "statutory." According to patent law, an invention is statutory if it is a "process," "machine," "article of manufacture," or "composition of matter." All other inventions are said to be nonstatutory. For example, computer programs or mathematical algorithms'^ are currently considered to be nonstatutory by the court. In the Diehr case, the Supreme Court decided for the first time that an invention does not become ineligible for a patent simply because of the presence of a

computer program in the invention. However, an invention must still fall in a statutory category and must pass the traditional tests for merit: it must be "novel," "useful," and "unobvious."

The court has yet to take the final step and say that software is patentable, but this important decision points in that direction,

Jacobs feels that now small businesses can afford to once again become innovators in the software field. Small-business entrepreneurs need patent protection to raise venture capital to bring their ideas to fruition.

Ruth M Davis, former director of the Center for Computer Services and Technology of the National Bureau of Standards, agrees that "there is a small-business potential to innovate in the software field...the patent system is important in stimulating [this] technological innovation."

The closeness of the 5 to 4 decision in the Diehr case has led some observers to conclude that the court is evenly divided on the software issue, but Jacobs is quick to point out that the court is becoming progressively more and more "pro-software" in its recent decisions. Further, the Supreme Court has had the benefit of advice and testimony from computer experts over the years, and the growing sophistication of its decisions reflects this.

Of course, the answers aren't all in yet. For example, what if an enterprising inventor puts a new program in a computer so that he can claim the novelty of the entire machine? This effectively preempts the algorithmic content of the program. The courts have balked at this approach in the past. Even so, the day may soon come when a program residing on a floppy disk will be granted a patent...CM

J

ing was affirmed by the US Court of Appeals for the Seventh Circuit, and precipitated considerable concern within the data-processing industry. It appeared that in the future, the only realistic defense against software piracy would be strict enforcement of licensing agreements. But a licensing agreement binds only those who are party to it. It has no legal effect on a pirate who obtains the software without signing an agreement.

The copyright problem was resolved by the Computer Software Copyright Act of 1980, which was passed in the waning days of the 96th Congress and signed by President Carter just before he left office. The Act amends the 1976 copyright stat

ute by defining a computer program as "a set of statements or instructions to be used directly or indirectly in a computer to bring about a certain result." The word "directly" refers, of course, to the object code. But while the new copyright law protects both the source statements and the sequence of machine instructions in the program, it does not protect the underlying logic of the program—the operations that the software is designed to perform.

The Patent Problem

The most effective way to prevent unauthorized use of computer programs would be to patent them. A patent would protect the process that

a program carries out, regardless of its specific form. True, the duration of a patent is short (17 years), but in a rapidly changing industry that disadvantage is only theoretical; for practical purposes, the protection afforded by a patent borders on the absolute.

Several attempts have been made to get the Supreme Court to recognize the patentability of computer software. In Gottschalk v. Benson (1972), the Court unanimously rejected a patent claim for an algorithm that converted numerical data in binarycoded-decimal form to pure binary. In his opinion for the Court, Justice William O Douglas started with the long-established proposition that "an

130 May 1981 © BYTE Publications Inc

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Asalesman generating 1.5 million dollars in sales annually for his company does so at the rate of $12.48 per minute. That's expensive time—should it really be used in rummaging through filing cabinets, writing long reports or talking to dozens of people looking for one small, crucial piece of information?

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idea of itself is not patentable," and concluded that granting a patent for the BCD-to-binary algorithm would amount to giving the applicant exclusive ownership of a mathematical abstraction.

At the same time, Douglas disclaimed any intention of foreclosing patent protection for computer programs altogether. He hinted that it would be best if Congress would resolve the issue of patentability of computer softwsire. But his opinion suggested that until Congress acted, the Court would avoid any sweeping

The protection afforded by a patent borders on the absolute.

ruling on the patent law and allow its interpretation to evolve on a case-bycase basis.

The Flock Decision

A few years later, in Parker v. Flook (1978), the Supreme Court ad

dressed an attempt to circumvent its ruling that an algorithm could not be patented. The case involved an application for a method of determining when a catalytic conversion process had exceeded certain predefined parameters. A computer program calculated alarm limits, which indicated when an inefficient or dangerous condition existed. While the applicant admitted that an algorithm was crucial to the patent application, he argued that he had tied its use to a specific industrial process—the catalytic chemical conversion of hydrocarbons.

The Supreme Court rejected Flook's contention by a vote of 6 to 3, holding that the only novel part of the process was the algorithm embedded in the computer program. The algorithm itself, under Benson, was of course not patentable. In his opinion for the Court, Justice John Paul Stevens said that both the chemical and mechanical processes involved were well known, and concluded that the patent application "simply provides a new and presumably better method for calculating alarm limit values." For patent purposes, mathematical algorithms, like laws of nature, were to be treated as though they had previously been known, even though in fact they were newly discovered by the applicant. "Respondent's process is unpatentable," Justice Stevens wrote, "not because it contains a mathematical algorithm, but because once that algorithm is assumed to be within the prior art, the application, considered as a whole, contains no patentable invention."

A Recent Interpretation

Was the Flook decision a fluke? Recent cases suggest it may have been. In the case of Diamond v. Chakrabarty (1980), the Court considered a patent claim for a laboratory-created bacterium. Superficially, computer programs and man-made bacteria have little in common (program bugs belong to a different species). Yet computer software and genetic engineering are alike in two respects: (1) Congress was unaware of either one when it wrote the basic patent

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134 Miy 1981 © BYTE Publkalioiu be

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Circle 348 on inquiry card. byte May 1981 135

law, which is only slightly changed from the language drafted by Thomas Jefferson in 1793, and (2) both programming and genetic engineering involve the manipulation of coded information which is stored (in one instance, in the electronic or magnetic memory of a computer and, in the other, in the molecular memory of a cell). But a 5 to 4 majority of the Supreme Court ruled in Chakrabarty that man-made microorganisms are indeed eligible for,patents.

In March of this year, the Court cited its reasoning in Chakrabarty as

justifying patent eligibility for a process involving a computer program. The case. Diamond v. Diehr, was also decided by a 5 to 4 vote. The Court ruled that a patent could be granted for a new method of curing synthetic rubber that was designed around a computer program. The program calculated the time required for the curing process by monitoring the temperature inside the curing furnace and continuously updating the time remaining. This allowed the program to stop the process the instant the rubber had been properly cured.

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The Justice Department, which opposed the patent application, said that the facts of the Diehr case were indistinguishable from those of the f/oofc case. Both patent applications were for industrial processes that were new because of the way they used computer programs. But Justice William Rehnquist, speaking for the Court, said there was a vital difference between Diehr and Flook. In Flook, the algorithm used to calculate alarm limits for the catalytic conversion process was new, but the idea of calculating alarm limits was not. In Diehr, the entire process was new; the essence of the patent application was that no one had ever successfully monitored the temperature inside the furnace and then used a computer program to continuously calculate when to stop the curing process.

Prospects

At this point it is difficult to tell whether or not the Supreme Court is in the process of reversing direction on the issue of software patentability. The most that can be said with any assurance is that the narrow majorities that have decided the recent cases indicate a deep division in the Court. A stinging dissent in the Diehr case by Justice Stevens, who was the author of the Flook opinion and who opposes any extension of patent protection for software, makes it clear that the debate is a long way from being resolved.

The Court was expected to take the case law one step further in its current term. It had agreed to rule in the case of Diamond v. Bradley, which involved a patent application for readonly memory routines used in the central processor of a computer for machine control. The Court of Customs and Patent Appeals, which has tended to be well ahead of the Supreme Court in authorizing patent protection for computer programs, held that the application should be granted. The Patent Court ruling was affirmed, but only because Chief Justice Warren Burger removed himself from the case (as is customary, he gave no explanation for his decision not to participate), leaving the other members of the Court evenly divided.

136 May 1981 © BYTE Publications Inc

Circle 330 on inquiry card.

Learn how to use a computer for $249. And keep tiie computer.

Introducing the Computer Learning Lab, with the Sinclair ZX80 personal computer

The Sinclair ZX80 is a powerful, personal computer already in use in tens of thousands of homes and businesses.

Now, for just $249*, the Computer Learning Lab will teach you and your children how to use this complete, expandable computer right in your own home. And when you're done, you get to keep the computer!

The Computer Learninq Lab is a self-paced course that teaches the ins and outs of computers. It cuts away jargon and mystique, taking you straight into BASIC—the most common, easy-to-use computer language. And the computer itself does the teaching.

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experiments that teach you how to solve problems with the ZX80.

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We'll also send you a catalog full of ready-to-use programs—from Loan Amortization to Lunar Lander—available for as little as $6.95.

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Name

Address

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only, without the Learning Lab, at $199.95' each.

_ (Add $5.00 for shipping.)

State

Zip

Occupation

Intended use otZXSO:

Age_

Have you ever used a computer? □ Yes □ No Do you own another personal computer? □ Yes □ No 05BY

While such a split leaves the lower court rulir\g ir\tact, it has no value as legal precedent.

What Does This Mean to Us?

For those of us with a recreational interest in the computer industry, there is little to lose and potentially something to gain from the change Congress has made in the copyright law and the possibility that the Supreme Court will increase the patent protection afforded computer software. True, now that object code is clearly subject to copyright, you will be breaking the law if you copy your commerical BASIC interpreter

Object code is now clearly subject to copyright laws.

for a friend. But the added protection provided by the new copyright amendments may encourage more software development, giving experimenters a wider selection of software products. It is even possible that vendors will begin to sell source code for microcomputer system programs (some even withhold information about useful program entry points)

because the code will be protected by copyright.

It is not clear to what extent the personal-computer market, a relatively small part of the overall microcomputer market, would be affected by a Supreme Court ruling that would enlarge the patent protection already granted to software-based industrial processes. But I suspect that any change in the patent laws that encourages innovation will increase the industry's interest in sources of innovation—that includes the tinkerers who develop potentially marketable software purely for their own amusement. ■

New Technology Clashes With Old Laws

Over the decades, different laws have been developed to protect different kinds of creative works. But computer software is not quite like anything that has preceded it. On the one hand, a software package may be thought of as a work of authorship. On the other hand, it is functionally mechanistic. Things are further complicated by the fact that it has become remarkably easy to copy large amounts of information quickly. Of course, the easier it is to reproduce a protected work, the harder it is to protect it.

The United States Constitution, in listing the powers of Congress, specifies that Congress shall have the power "to promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive rights to their respective writings and discoveries" [Article I, Section 8]. Congress has exercised this power by enacting patent and copyright laws.

Patent law is set forth in Title 35 of the United States Code. It affords strong protection, for a period of 17 years, to demonstrably useful, novel, and nonobvious inventions. Whereas copyright is designed to protect the "expression" of an idea or process, a patent is designed to protect inventions, which are products or processes in themselves.

Although patents have been awarded to software, the rigid standards of novelty and nonobviousness have made application difficult.

Similar confusion has existed with regard to the applicability of copyright laws, The disagreement among those caught up in the necessity of applying old laws to new phenomena was brought into focus during the 1970s as Congress attempted to overhaul the 1909 copyright laws.

Concurrent with the activity in Congress, a commission was formed in 1975 to address the copyright problems of data processing. CONTU (the National Commission on New Technological Uses of Copyrighted Works) examined various existing laws that could, presumably, be modified to protect data bases and software. In 1978, CONTU issued its Final Report, a study that recommended appropriate changes to the copyright law, based on the results of its research. (Final Report, stock number 030-02000143-8, is available from the US Government Printing Office.)

Although a new Copyright Act was passed in the fall of 1976 (effective January 1, 1978), Congress decided that the implications of data processing and reproduction technology had to be further

clarified before they could be properly reflected in the new law. Accordingly, a stop-gap paragraph was inserted which indicated that the old laws, though ambiguous, still pertained. Subsequent revision (most particularly the Computer Software Copyright Act of 1980) continues to provide inadequate protection.

An interesting historical parallel to the debate over software protection occurred in 1908, when the Supreme Court held that a piano roll was not a "copy" of music because it was not, for most purposes, humanly readable (WhiteSmith Music Publishing Co v. Apollo Co, 209 US 1). For similar reasons, it has been argued that a program in object code lacks communicative potential and might therefore be constitutionally uncopyrightable. But, as CONTU points out, copyright protection has been extended by the courts to such diverse works of authorship as freight tables, interest tables, and lists of similarly meaningless five-letter code "words." These works of authorship, like computer programs, are valued for their utility, rather than their artistic merit.

Ross Olmsted

58 Grand Ave, #20

OrovUle CA 95965

138 May 1981 © BYTE Publications Inc

WRITE FOR OUR CATALOG WITH FULL PROGRAM DESCRIPTIONS AND SPECIFICATIONS.

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NO. 20

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ACCOUNTS PAYABLE (PTREE) ACCOUNTS PAYABLE (SSG) ACCOUNTS RECEIVABLE (PTREE) ACCOUNTS RECEIVABLE (SSG) GENERAL LEDGER II (CPAIDS) GENERAL LEDGER (PTREE) GENERAL LEDGER (SSG) GLECTOR FOR SELECTOR III-C2 INVENTORY (PTREE) INVENTORY (SSG) PAYROLL (PTREE) PAYROLL (SSG)

PMATE: EDITOR-IN-CHIEF

"Tliis new-generation text editor is bristling with features previously unavailable on microcomputers, making it ideal for virtually any program or data file editing. PMATE'S command set includes expression evaluation, con4.tional branching, I/O with prompting, and other programming language constructs. PMATE makes use of 11 buffers for storage, and includes commands permitting work on more than one text at a time. Unique to PMATE is the facility for customizing. Keystroke functions can be redefined, and sequences can be programmed to directly execute macros. Video commands can be changed, and macro functions can be written to emulate another editor, such as M)RDSm™ or ELECTRIC PENCIL™. PMATE provides full sidescrolling, and can be used with virtually AM video terminal on the market. PMATE is an extraordinary editor, combining the power of TECO™ with the convenience of TORDMASTER™. IF you use an editor, you need PMATE!" PMATE $195

MICROSPELL SPELLING CORRECTION PROGRAM AVAILABLE FOR $295.

LIFELINES

PASCAL USER MANUAL AND REPORT PAYROLL WITH COST

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PROGRAMMING

USING CP/M—A SELF-TEACHING GUIDE

NUMERICAL PROBLEM-SOLVING TOOLS

ANALYST FPL

muMATH

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OTHER SPECIALIZED APPLICATIONS

BSTAM

BSTMS

DATEBOOK ESQ-I

MASTER TAX PAS-3 DENTAL PAS-3 MEDICAL

PROPERTY MANAGEMENT (PTREE) STANDARD TAX

BOOKS AND PERIODICALS

APL—AN INTERACTIVE APPROACH ACCOUNTS PAYABLE & ACCOUNTS

RECEIVABLE-CBASIC 8080/Z80 ASSEMBLY LANGUAGE THE CP/M HANDBOOK THE C PROGRAMMING LANGUAGE FIFTY BASIC EXERCISES GENERAL LEDGER-CBASIC

ACCESSORIES

DC 300 DATA CARTRIDGE HEAD CLEANING DISKEHE FLIPPY DISK KIT FLOPPY SAVER

Program names and computer names are generally trademarks or service marks ol the author or manulacluring company.

All soltware products have specific requirements tor hardware and additional associated sollware (e.g. operating system or language}. All Lileboat software requires CP/M unless otherwise stated.

All products are subject to terms and conditions of sale.

Copyright c, 1981 Lileboat Associates. No portion ol this advertisement may be reproduced without prior permission.

The list of available formats is subject to change without notice. In case of uncertainty, call to confirm the format code for any particular equipment. Prices and specilications are subject to change without notice.

Ordering Information

COMPUTERS SUPPORTED WITH MEDIA FORMATORDERING CODES.

1

ADDSMullivision RT

AVL Eagle RB

Altair8800 Bl

Alios AI

Apple CP'M 13 Sector RG

AppleCP M leseclor RR

BASF Syslem 7100 RD

Blackhawk Micfopolis

Mod II Q2

Blackhawk Single Densily . .Q3

CDS*i5alllc3B Q1

C0S\*rsaliie4 Q2

MMPAL-80 Q2

CSSN Backup T1

Cromemco System 3 AI

Cromemco Z2D R6

Delta Systems AI

Digi-Log Microterm II RO

Digital lificrosyslems AI IMS 5000 RA

DurangoF-85 RL IMS 8000 AI

Dynabyte DB8/2 R1 IMSAI VDP-40 R4

Dynabyte DB8/4 AI IMSAI VDP-42 R4

ExidySorcefer Lifeboat IMSAI VDP-44 R5

CP/M Q2 IMSAI VDP-80 AI

Heath H8- H17/H27 disk., ,P4 ISC Intecolor

Heath H89 +Lileboat CP/M P4 8063/8360/8963 AI

Heath H89 + Magnoiia Intertec Superbtair DOS 0.1 R7

CP/M P7 Intertec Superbrain DOS 0.5 RJ

Heliosll B2 IntertecSuperbrain D0S3.XRK

ICOM 2411 Micro Floppy .. ,R3 Intertec Superbrain QD . . RS

ICOM 3712 AI Kontron PSI-80 RF

ICOM 3812 AI

ICOM 4511 5440 Cartridge

CRM 1.4 D1

ICOM 4511 5440 Carlcidge

MITS 3200-3202 Bl

MSD5.25in RC

MecaDelta-1 5.25 in P6

Micromation AI

.01

Micropolis Mod II 02

Morrow Discus At

Mostek AI

North Star Single Density...PI North Star Double Density.. P2 North Star Ouad Density . .P3 NylacMicropolis Mod II.. . .02

Nylac Single Density Q3

OhioScienlilicCS A3

OnyxCSOOl T2

Pertec PCC 2000 AI

Processor Technology

Helios II 62

Ouay500 RO

Quay 520 RP

RAIR Single Density R9

RAIR Double Density RE

Research Machines 5 25 in RH

CP/M 2.2 02 Micropolis Mod I .

Lifeboat Associates, 1651 Third Avenue, N.Y., N.Y 10028 (212) 860-0300 Telex: 640693 Circle 445 on inquiry card.

Research Machines 8 in . . .AI

Rex 03

SD Systems 5.25 in R3

SD Systems 8 in AI

Sanyo 7000 5.25 in RQ

Spacebyte AI

TEI5.25in B3

TElBin A1

TRS-30 Model I

STANDARD R2

TRS-80 Model I - FEC

Freedom RN

TRS-80 Model I

Micromation A4

TRS-80 Model I • Omikron

5.25 in RM

TRS-80 Model t + Omikron

.At

TRS-80 Model I +

Shullleboard AI

TRS-80 Modem AI

TRS-aO Model III RU

Vector MZ Q2

Vector System B 02

VislaV-80 5.25 in. Single

Dens R8

Vista V200 5.25in. Double

Dens P6

Zenith Z89 + Heath CP/M . P7 Zenith A89 + Lileboal

CP/M P4

Zenith Z89 ^ Magnolia

CP/M P7

In Germany, ^ Intersoft GmbH, Schlossgartenweg 5, "-^ i-«M«Bt

D-8045 Ismaning Telephone 089/966-444 Telex: 5213643 isof In Switzerland,

Lifeboat Associates GmbH, Aegeristr 35, CH6340 Baar, Telefon: 042/31 2931, Telex: 865265 MICO CM

iifeboal Associates,

SUPER* MARKET

Legal Protection for Computer Hardware and Software

Stephen A Becker Lowe, King, Price & Becker

Suite 209 2001 Jefferson Davis Hwy Arlington VA 22202

Picture the following:

Tinkering at your home, you develop a program or hardware innovation that, you believe, can be sold for a handsome sum. When you consider marketing your development, justifiable paranoia strikes, as it becomes painfully apparent that an unscrupulous competitor could easily copy your program (by exact reproduction) or hardware (by duplicating the schematic diagram or by employing reverse engineering).

Question: How can a hobbyist or small businessman, with limited resources, guarantee that the law will provide protection against such unfair competition?

Answer: There are no guarantees.

Patents, copyrights, and trade secrets are the three basic forms of legal protection that are primarily applicable to computer-related innovations. Unfortunately, there is no single form of protection for all the different varieties of hardware and software that is entirely satisfactory to the small businessman. In fact, this also applies to large businesses with virtually unlimited resources.

About the Author

Stephen A Becker has a master of science degree in electrical engineering. He has been granted two patents for his work in electronic control systems while working as a research engineer. After obtaining a law degree in 1975, he entered the field of patent laWj Attorney Becker specializes in the protection of intellectual property innovations, with particular emphasis on computers, and is a partner in the patent law firm of Lowe, King, Price fir Becker.

The following discussion provides some general legal background on a very complex and growing subject. However, I encourage you to confer with a patent attorney (registered with the United States Patent and Trademark Office) who specializes in all forms of intellectual property protection, prior to entering the marketplace. Also remember that this discussion concerns US law only. If you have an international market, professional advice is even more essential.

Patents

Patents provide a formidable protection for innovations that meet the rather stringent legal requirements of patentability. The right to a patent is fragile and can be lost by certain avoidable acts, such as public disclosure or an offer for sale more than one year before the patent is applied for. A patent, once granted, gives the patent owner the exclusive right to make, use, or sell the patented innovation in this country for 17 years. The patent owner has the right to stop others from infringement and collect damages even if the infringer later developed the same invention independently. After the 17-year period has expired, the innovation is considered to be in the public domain and available to all without limitation.

In order to qualify for a patent, the invention must be new, useful, and unobvious in view of existing technology. In fact, before a patent is granted by the United States Patent and Trademark Office, a patent examiner conducts technological re

search to determine whether the invention is adequately different from the existing technology to merit an award of "Letters Patent." About one dozen patent examiners, who specialize in computer technology, work for The Patent and Trademark Office.

Unfortunately, the procedure of applying for a patent is very expensive. In most cases, a patent attorney or agent must be retained to prepare a patent application and to submit arguments in favor of patentability before the Patent and Trademark Office during the approximately 18-month period of examination. During this time no patent protection exists. Patent rights are created only when a patent is actually issued. Furthermore, there is no guarantee that you will receive a patent. The Patent and Trademark Office may rule that the invention does not qualify for patent protection. They may do this for one of two reasons: because the invention is not the type that patents are designed to protect (eg: mathematical algorithms) or because the invention is simply too close to existing technology to be considered "unobvious."

It is definitely possible to obtain a patent on hardware innovations, such as peripherals, interface circuitry, or construction techniques. There is considerable uncertainty, however, concerning what types of computer software, if any, can be protected by a patent. In 1972 and 1978, Supreme Court litigation between patent applicants and the Patent and Trademark Office resulted in denials of patent protection on programs that

140 May 1981 © BYTE Public;itiaiu Inc

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Prices reflect 3% cash discount. Product shipped in factory cartons with nnanufactures warranty Add 2%, a minimum of $5, for shipping and handling.

are essentially mathematical algorithms, such as numerical conversion.

But in more recent cases (in 1980 and 1981) the Supreme Court begged the question of whether or not other types of software may be patentable. The Court of Customs and Patent Appeals (CCPA), which reviews Patent and Trademark Office decisions and is highly regarded for its competence in patent matters, has held that certain other types of software may be patentable. Issuance of patents has been denied by the CCPA only on software that is essentially algorithmic in nature. Thus, it is still unclear what types of software will ultimately be considered patentable if and when that broad issue is considered by the Supreme Court.

On the other hand, the courts have held that inventions are not unpatentable merely because they involve programming. For example, consider a microprocessor-based system that is programmed to operate with an array of sensors to monitor a physical parameter in a unique way and to process sensor-generated data in accordance with a stored program, generating machine-control signals. This system is patentable if it satisfies the three basic criteria of novelty, usefulness, and non-obviousness. Thus, patent protection is available to computer-related innovations involving programming so long as the invention is in the overall system and not solely in the program.

Because the costs involved in obtaining patent protection are high and the law of software protection is still

uncertain, I do not recommend patents as an avenue of protection of programming by the personal computer experimenter or small businessman. However, if the invention involves more than just programming (eg: a complete system involving programming, or a new piece of hardware) and there is a significant commercial potential associated with the invention, then Letters Patent should be considered to increase the likelihood of success in the commercial environment.

Copyrights

A copyright is essentially the right of an author to control the copying of his or her work by others. It is applicable to computer software but not hardware. A copyright is easy and inexpensive to obtain. It must include the follovying comment at the start of the program:

© <name of copyright owner > < date of first pubIication>,

© John Doe 1979

In order to perfect the copyright, as is necessary before a copyright infringer can be sued, the copyright must be registered with the Copyright Office by filling out a FORM TX. (The address is: United States Copyright Office, Library of Congress, Washington DC 20559.) After you fill it out, mail it with two copies of the program as originally published (or publically disseminated) and a $10 registration fee.

If the program is on magnetic tape

or other non-readable form, a printout must also be deposited. Even if you do not register the copyright, you are required to deposit copies with the Copyright Office within three months of the date of first publication of the program with the copyright notice.

As a practical matter, however, there is no penalty for non-deposit in the absence of registration, unless the Copyright Office specifically demands a deposit. Details on software registration can be obtained directly from the United States Copyright Office or from an attorney specializing in intellectual property law.

The term of a copyright extends throughout the lifetime of the author plus 50 years. In the case of a work made for hire, the term is the earlier of two periods: 75 years from the year that the work (ie: program) was published, or 100 years from the year that the program was written.

Although the cost and effort of obtaining a copyright on software are minimal, and although there is virtually no time delay or uncertainty (as in patents), a copyright offers substantially less protection than a patent. First, the copyright covers the "expression" (ie: program listing) of software but not the idea, procedure, or concept underlying the software. A competitor could, for example, use the copyright owner's basic procedure or method of solution without infringing the copyright if a different but equivalent program is developed. Also, the copyright owner is provided no protection against competitors

6809 SYSTEMS ^ 6809 SYSTEMS 6809 SYSTEMS 6809 SYSTEMS

Featuring the GIMIX mainframe with 30 amp C.V. ferro-resonani power supply; fifteen 50 pin and eight 30 pin slot Mother Board:

2 Mhz CPU with time of day clock & battery back-up. 1K RAM, 6840 programmable timer, provisions lor 9511A or 9512 Forintonnalion, pricing and brocliures, contact:

Arithmetic processors, and 4 PROfVI/ROI^/RAM socl^ets tliat can tiold up to 32KB of monitor or user software. ^^■■^^■■'^ ^

VARIETY: you can have 32KB, 56KB, 128KB and up of static RAI^. You can use 5" and/or 8" disk drives, single or double ^^^l^^lB 3t I^C.

density, single or double sided, and single or double tracking with GIMIX disk controllers. You have a wide choice of serial or I / ■■111 I parallel I/O cards. V "■*'

EXPANDABILITY: You can add nnemory, l/Os, Video or Graphics cards, Arithmetic processors, additional drive capacity, and other ""•"'I' electronic products since ms.

hardware now or in the future to this SS50 bus structured system from GIMIX or other SSSO bus compatible manufacturers. 1337 WBST STHi PLACE, CHICAGO, IL 60608 SOFTWARE VERSATILITY: GIMIX systems can use TSC'S FLEX or UNIFLEX and MICROWARE'S OS-9 operating systems. A wide (312) 927-S510 • TWX 910-221-4055 variety of software and languages Is available for these systems. riMre

DUALITY: All boards are assembled, burned-in. and tested and feature GOLD PLATED BUS CDNNECTORS. Only top guality com- '™ registered trademarks

ponents are used and ail boards are fully buttered for maximum system expansion. All boards come complete with bus connectors

and all necessary instruction and documentation. Flex and Unillex are trademarks of Technical Systems

GIMIX designs, manufactures and tests, In-house, their complete line ol products. Complete systems are available to fit your Consultants inc. 0S9 is a trademark of Microware inc. See needs. Please contact the factory If you have any special requirements. , """" •5"""' compatible sotiware.

For GIMIX compatible software see Tecfinlcal Systems Consultants ad page 77 and Microware ad page 242.

See us at NCC booths 971-2.

142 May 1981 © BYTE Publicadons Inc

Circle 167 on Inquiry card.

Development Software

For Texas Instruments TM990 Micro Modules

Eyring Research Institute, Inc., authors of Tl's POWER BASIC® and UNIVERSITY BASIC®, is pleased to release development software for use on the TM 990 microcomputer modules. PDOS/ EXPRESS® is a powerful multi-user, multi-tasking operating system designed for development, scientific and industrial applications.

The PDOS/EXPRES® system includes:

• 8k byte PDOS multi-tasking operating system

• Advanced EXPRESS BASIC language interpreter

• Stand alone run module support

PDOS supports up to 16 concurrent user tasks with prioritized round robin clock swapping. Up to 32 contiguous or noncontiguous files can be simultaneously open in sequential, random, shared and read only access modes. Large or small floppy disks, bubble memory, hard disks

"After having worked with PDOS and EXPRES for the past three months I have found them to be a powerful and versatile combination. The true multi-user, multi-tasking capability has made it a pleasure to use in our labora tory environment where programs are being used simultaneously for controlling laboratory apparatus taking and reducing data. . .We are enthused by the product. . ."

Tom Ochs

Assistant Research Professor Desert Research Institute

and extended memory capabilities of up to 256k bytes are handled by the operating system. Named files on 256 directory levels are easily accessible from EXPRES BASIC and assembly language programs. Disk files are time stamped with date of creation and last update. I/O drivers are a simple extension to the PDOS file structure.

The EXPRES BASIC interpreter uses advanced interpreting techniques which approach execution speeds of common threaded code compilers while maintaining the highly advantage

ous interactive approach to program development. Other features include:

• Multi-line recursive functions with local variables

• Variable names of unlimited length

• Reverse Polish pseudo-source token storage

PDOS/EXPRES® is available for either an EPROM based system or a RAM based system. A handsome 250 page Operator Reference Manual walks you through the features and use. All for an attractive price of $1500.00*.

Order your PDOS/EXPRES® software from your nearest authorized Texas Instruments distributor or contact Eyring Research Institute, Inc. for further information and a free color brochure. Write or call Eyring Research Institute, Inc., Software Marketing Dept., 1455 West 820 North, Provo, Utah 84601, phone (801) 375-2434.

Eyring Research Institute^ Inc.

*U.S. price, subject to change without notice

Circle 159 on Inquiry card.

BYTE May 1981 143

who independently develop the same program; a copyright offers protection only against actual copying.

This may be enough protection for many computer programs. But the form of expression of a program is often critical and modification of that expression often destroys or substantially reduces its utility. I recommend that programmers routinely include the copyright notice in a comment statement at the start of each program prior to distribution, and postpone registration of the copyright until a lawsuit for copyright infringement is contemplated.

A word of caution concerning copyrights: there is presently some uncertainty whether, and to what extent, computer programming is a proper subject for copyright protection. An early attitude was that programs could not receive copyright protection because they are part of a machine rather than a literary work. Present sentiments, however, are that at least the "expression" of the program should be protectable by copy

right. This issue may soon be settled because Congress is expected to consider subcommittee recommendations to amend the Copyright Act.

(Editor's Note: Source listings are unequivocably covered by copyright laws, but the extent of copyright protection as it is applied to programs in other forms is less clear. For further explanation, and a discussion of Supreme Court rulings regarding software patents, see "Washington Tackles the Software Problem," page 128.)

Trade Secrets

A trade secret is commonly defined as a formula, process, mechanism, compound, or compilation of data, not patented, but known only to certain individuals using it in business to obtain a commercial advantage. In order for there to be a trade secret that will be enforced by the courts, a secret must exist and there must be a duty on the part of all persons who learn the secret not to disclose it. Confidential relationships are generally established between employers

and employees or between businesses cooperating in a technical development by a type of contract known as a confidential disclosure agreement. For example, if you, a small businessman, wish to submit your unpatented innovation to a corporation for evaluation you may request that a corporate officer sign a confidential disclosure agreement. Such an agreement states that the corporation agrees to use your disclosure only for the purpose of evaluation and to disclose it outside the company only with your express written approval. The agreement will require the company to bind all its employees to confidentiality. However, the agreement must not be too restrictive to prevent the company from properly evaluating your innovation. Some companies may not be willing to sign a confidential disclosure agreement and, in fact, may even require you to agree to non-confidentiality before they will review an outside irmovation.

A trade secret automatically exists between a patent applicant and the Patent and Trademark Office during the period of examination of the patent application. The Patent and Trademark Office is required by law to maintain the application in secrecy.

The Coca-Cola formula is an example of a successful trade secret which has never been patented and is known only to some internal personnel. For a trade secret to exist the subject matter must, in fact, be maintained in secrecy. But trade secrets are easy to lose. Once the secret becomes public, for example, legal protection is lost. It may become public through your own carelessness or through commonplace and legal competitive means, such as reverse engineering. A trade secret is not lost, however, if a competitor obtains the secret by unfair means, such as industrial espionage. The courts are filled with lawsuits involving piracy of trade secrets—including cases that involve theft of software and data by such means as tapping communication lines.

One advantage of trade secrets, in contrast with either patents or copyrights, is that the trade secret exists as

ATTENTION GOVERNMENT D P USERS AND PURCHASERS

We represent many fine micro products and manufacturers on the GSA Schedule, including

Apple, Cromemco and Computer Corporation of America

Purchasing from the Schedule will save you the time consumed by the bid process. Products shipped throughout the United States and world-wide. Visit or write any of our stores for more information or to receive our catalogue of products represented.

the dependable store

257 West Street, Annapolis, MD 21401 - (301) 268-6505 13A Allegheny Avenue, Towson, MD 21204 - (301) 296-0520 9330 Georgia Avenue, Silver Spring, MD 20910 - (301) 588-3748 or Call(301) 268-5801

Career Opportunities Available *An Equal Opportunity Employer

144 May 1981 © BYTE PublicaUons Inc

Circle 92 on inquiry card.

Software Professionals

At General Electric we're using computers in ways no one thought of before.

If you are looking for exciting technical challenges coupled with excellent growth opportunities join General Electric's Space Systems Division. Help us develop large scale, distributed, information processing systems requiring innovative design approaches. You

Entry level and Sr. positions available for

will be working in the following Data Processing Environments:

■ 3033 ■JES2

■ 3081 ■ ACF/NCP

■ VAX 11/780 "AD ABAS

■ MVS

MVS Systems Programmers

Perform SYSGENs, maintain and tune MVS. Select and install program products. Develop MVS enhancements, H/W-S/W interfaces, and 3705 telecommunications applications.

Math Analysts

Perform modeling for simulation of complex command and control systems. Solve operational research problems and develop algorithms in systems and vehicle flight dynamics and orbit mechanics. Develop computer programs to generate study data to aid analysis and trade-offs.

Computer Systems Architects

Responsible for requirements analysis in the design of large scale Computer Systems to support on-line information management applications. Duties include selection and specifications of:

• Computer Hardware

• Operating Systems

• Data Management Systems

• Telecommunications Systems

Data Base Designers/ Administrators

Perform data base design-administration and implementation tasks for large scale data systems using state-of-the-art data base management tools. Analyze data base requirements. Design and select file structures, access methods, and data management techniques. Install, maintain and tune vendor supplied Data Base Management packages. Provide Data Base support and technical interface for Data Base definition, design, query and update utilities.

Data Base Analysts

Responsible for data requirements analysis and subsequent selection of appropriate data management approaches including Data Base Management Systems evaluations.

Scientific Programmer/Analysts

Perform start-to-finish, state-of-the-art S/W development for large scale, high technology programs. Develop geometric and operations research related designs that involve challenging data handling requirements. Growth opportunities available include entry level to Project Leader positions for those with demonstrated leadership/technical skills.

For your convenience, a postage-paid reply card has been provided. One of our Technical Managers will contact you promptly. Or, if you prefer, you may respond by sending

a resume or letter to: Mr. William E. Sarno, Dept. VF-31-E, General Electric Space Systems Division, Valley Forge Space Center, Goddard Blvd., King of Prussia, PA 19406.

Applying computers to make our most important product: Progress

GENERAL

ELECTRIC

GE takes pride in being an equal opportunity employer, m/f

BYTE May 1981 145

Circle 97 on Inquiry card.

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long as the secret is maintained; it does not expire after a predetermined finite lifetime. There are no formal procedures, applications to fill out, or government fees to pay to establish a trade secret. Furthermore, there are no delays because the trade secret becomes enforceable as soon as it exists.

Unless you are in a position to maintain your software in secrecy and to bind all parties involved in confidentiality by contract, a trade secret is apt to be lost through inadvertence or by acceptable competitive efforts. For example, in the absence of restrictive licensing, there are no legal means to prevent a competitor from purchasing your software for the purpose of reproducing it for sale to his own customers. Of course, if the printout carries the copyright notice and the program is copied by the competitor verbatim, you will have a claim for copyright infringement following registration of your copyright with the Copyright Office.

Trade secret protection is at best very risky and can be lost for any number of reasons both inside and outside your control. In addition, there is some conflict between copyright law and trade-secret law since copyright protection is based upon publication, whereas trade-secret protection prohibits publication. Therefore, care must be taken to indicate that there is no presumption of publication of programs carrying the copyright notice that are distributed under restrictive licenses or confidential disclosure agreements. Even then, once the program is deposited with the Copyright Office, trade-secret protection may be lost.

Protection

The type or types of protection that should be considered for programs and computer-related developments depend upon several factors. These are:

• the nature of the development, that is, whether it is basically a mathematical algorithm of some other type of program or computer-based system merely involving programming

• the commercial importance of the

invention

• the commercial lifetime of the invention

• the importance of exclusivity in the marketplace

Patent protection should be considered for hardware, or for computer-based systems, when the novelty involves more than merely the programming, if there is significant commercial potential and there is a commercial lifetime of at least several years.

Software should bear the copyright

notice, despite uncertainties in the law, and I even recommend applying the copyright notice to printed-circuit boards to protect direct copying of circuit layouts. Trade secrets should be relied upon only when you are in a position to actually maintain your software or hardware systems in secrecy and bind your employees to secrecy and customers by contract; this is generally not practical where public sales are made. An old practice for maintaining circuitry in secrecy has been to embed the circuitry in epoxy, to prevent reverse engineering by inspection. It may even be necessary to embed small metal particles in the epoxy to prevent inspection by X-ray photography. Obviously, this approach is impractical for the small businessman working in the public market.

Whenever possible, software should be sold under restrictive licenses between you and your customers. Under the license terms, the software remains your property, while the customer is permitted to use it but not reproduce the program for use by others. A patent attorney will be able to draft a restrictive license to meet yovur particular requirements.

Most patent attorneys are also engineers who specialize in all areas of intellectual property, such as patents, trademarks, copyrights, and trade secrets; they are in a position to develop a portfolio of intellectual property protection suitable to your particular needs. I strongly recommend that you consult one before you attempt to market any product. ■

146 May 1981 © BYTE Publicatknu Inc

The talk of the town!

General Instrument's new VSM2032 has made speech synthesis the talk of the town. In fact it speaks so well we named It Orator.™

The VSM2032, a complete speech system, is immediately available. It needs only a power source and speaker to start talking...in less than an hour you can hear it speak, fluently, with a 32 word calculator/clock vocabulary that combines to form over one billion phrases.

You can use the Orator module as a stand alone voice system or interface it with industrial equipment, vending machines, instrumentation, arcade games, computers or warning devices.

More than the spoken word.

With Orator you get a lot more than talk. General Instrument's state-of-the-art technology utilizes Linear Predictive Coding (LPC) for speech data compression with minimum ROM support. And to obtain truly natural speech, a 12 pole cascade filter is used to implement a mathematical model of the human vocal tract so that Aunt Mary sounds exactly like Aunt Mary and not like Uncle Walter.

Now. Talk's cheap.

Simplified digital interfacing... immediate availability...high voice quality...low price...make Orator VSM2032 an attractive and feasible way to make your product speak. At a cost of $99 (signifi

cantly less in production quantities), you can't afford not to

hear Orator! And you can choose from standard vocabularies or your own vocabulary for orders of 250 or more modules.

The final word is up to you. The \/SM2032 is available now from these distributors. Advent, Anthem,

Arrow, Diplomat, Future, Hallmark, Pioneer and VSI. Or write Module Products Dept., Microelectronics Division, General Instrument Corporation, 600 West John St., Hicksville, New York 11802.

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GENERAL INSTRUMENT

Software Review

Dancing Demon from Radio Shack

Elizabeth Cooper and Yvon Kolya

FOB 22 Peterborough NH 03458

Radio Shack's latest addition to its games line is a fantastic graphics and sound game called Dancing Demon. The author of this well-designed gem is Leo Christopherson—the creator of Snake Eggs and Bee Wary, those wonderfully graphic but nonsensical games.

Dancing Demon is a fairly sophisticated music-generating program which uses carefully synduronized moving graphics and impressive sound.

Written in BASIC, the game places you in the role of agent/operator of

At a Glance

Name of software package

Dancing Demon

Type of package Game

Manufacturer

Radio- Shack 1600 Tandy Center Fort Worth TX 76102

Price $9.95

Format Cassette tape

Language used BASIC

Computer needed TRS-80, Uvel II BASIC, 16 K programmable memory

Documentation

13 pages, 8V2 by 11 inches

Of interest to

Children, parents and grown-ups who

are kids at heart

an ex-devil called the Dancing Demon. As his agent you must choreograph his dance steps to music you compose.

The documentation is careful to explain that the demon is rather dimwitted and understands only a special code for the music and dance steps. This code assigns one note to each letter of the alphabet. Covering a full two octaves (25 notes total) the "A" key equals low C and the "Y" key is equal to high C. The "Z" key is reserved for rests between notes.

After selecting the demon's music, you are given the opportunity to choose his dance steps. (If you wish, you can select the dance steps first; the order is up to you.) The same simplistic approach is also used for this procedure. The letter "A" represents Step 1, the letter "B" represents Step 2, and so forth to the letter "Z," a total of 26 different steps.

The instructions are clear and to the point; at times, they are clearly geared towards young children.

The program is as easy to understand and the documentation is clearly written. After CLOADing it and typing RUN, you see the main program menu. The menu options are:

1. Compose your own music

2. Create your own dance routine

3. Make the demon perform the pro

gram in memory

4. Save your show to tape

5. Load a show from tape

6. Make the demon perform the first preset show

7. Make the demon perform the second preset show

The last two options are usually the first ones chosen. These two opening numbers give a good example of the capabilities of the demon and are quite entertaining.

Continuing up the menu in reverse order, you have the option to LOAD (from tape) a show previously composed, or to save to tape a show you have just perfected. Both of these options are arranged simply so children should experience little difficulty.

Option three lets you play the show currently in memory. You are asked two questions: The first question asks for a speed factor, which determines how fast the music plays, and how fast the demon executes the dance routine. Any number between 1 (super fast) and 255 (very slow) may be entered.

The second question asks how many performances of this routine you wish to see. Again, you may answer with a number between 1 and 255.

After you've answered the questions the screen displays the theater stage, the curtain rises, and the demon starts his performance.

Option two lets you program the dance steps to be used by the demon. The steps have enough variety to be entertaining and yet the differences are subtle enough so that any combination of steps will result in a credible dance routine. Since the steps are designated by letters of the alphabet, you can amuse yourself by typing in actual sentences and watching how these are translated into movements by the demon. You can even type in the words to the song you've just

148 May 1981 © BYTE PublicaUoiu Inc

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entered into the music section of the program.

One very nice feature is the "preview." By pressing the space bar you can see the demon dance the routine as you have entered it so far. If you don't hke it, you can easily change it. The only restriction is that you are limited to a maximum of 248 dance steps in the routine.

Once you're satisfied with the dance routine performed by the demon, you enter it into "permanent" memory by pressing the ENTER key.

This also returns you to the main menu. Finally, option number one lets you enter the music to which you want the demon to dance.

While the basic idea of the musical accompaniment seems quite simple, in actuality, it is considerably more difficult to create (or recreate) a musical melody than it is to design a workable dance routine. As with the dance steps, each note is designated by a letter of the alphabet. To include a rest, the "Z" key is used. What's confusing is the fact that there cannot

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be a direct correspondence between the letters of the keyboard and the letters of the musical scale. This is because the sharps, flats, and octaves (ie: the notes low C, low C#, high C, etc) cannot all be matched to the keyboard letter "C"; instead, they are matched to the keyboard "A," "B," and "M" keys, respectively. Even for someone who already plays music of a more conventional sort, it's like learning an entirely new instrument. For those who read music, a chart matching the keyboard letters to their appropriate places on the musical staff might have been a very welcome addition to the documentation.

Then again, it might be easier to take the advice in the instructions and simply pick out tunes by ear. When you're programming music, each press of a key results in the appropriate note being played, and the appearance of that key's symbol on the sequence list.

To hear the sequence you've input so far, press the space bar. This is an excellent feature, since it is always encouraging to hear your progress up to this point, and it's easier to spot and correct mistakes. As in option two, when you're satisfied with the music sequence, press ENTER to have it added to memory, and to return to the main menu. You are limited to a sequence of 248 notes. There's no need to worry about having the same number of notes as you have dance steps. The music sequence repeats (if necessary) until all of the dance steps in the sequence have been executed.

Conclusions

Dancing Demon, Radio Shack's newest graphics and sound game, is an admirable addition to its game line. It combines an entertaining graphics routine with an equally amusing sound routine (including the clicks from the demon's tap-dance shoes). Because of the unusual combination of sophistication and simplicity, this game could be an excellent means of sparking and fostering the creativity of children.

The game sells for $9.95 and, we feel, it should be purchased by anyone with children. We heartily recommend it.H

150 May 1981 © BYTE Publications Inc

Circle 331 on inquiry card.

31 MByte Formatted Capacity

The ADES S33 MByte Hard Disk Subsystem is the HARD EDGE in System Performance. The S33 transforms your S100 computer from a slow, floppy-bound machine into a high performance system. The S33 is a complete subsystem which includes the ADES PS100 SI 00 compatible hard disk controller card, the Priam DISKOS (TM) 3350 hard disk, an attractive desktop cabinet, power supply, CP/M* BIOS software, and ribbon cable. With its 31MB formatted capacity and a CP/M data transfer rate greater than 40K bytes/second the 833 can instantly increase the performance of any S100 computer system.

S3] FEATUBES. The PS100 single card controller, which is IEEE-SI 00 connpatible, contains an on-board processor, a 528-byte host interface RAM, and the hard disk interface. It has a fifteen command repertoire, on-board CRC to guarantee data integrity, user selectable base address, bank select feature, phantom BAM disable, and lull S100 interrupt capability. It controls up to four Priam drives. In addition, the S33CBI0S software package allows easy integration into most CP/M systems. Application notes cover CBIOS integration and system boot directly from the hard disk.

EXPANDABILITY. With the S33 subsystem, you have freedom to grow in two different directions. First, the PS100 controller supports all Priam 8- and 14-inch hard disk drives, including the 68 MByte and 158 MByte models. As your database expands, so does your system's capability. Second, one PS100 controller handles up to four drives of any size and in any combination, providing a full range of capacities.

The S33 is only the first in the expanding line of ADES mass storage products. When you need an edge on your competition or more power in your personal system, look to ADES for the "HARD EDGE in System Performance."

'CP/M is a registered trademark ol Digitai Research.

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circle 4 on Inquiry card.

ADAPTIVE DATA & ENERGY SYSTEMS 2627 Pomona Boulevard • Pomona, CA 91768 Phone: (714) 694-5858

Wire-Wrapping and Proto-System Techniques

Adolph Mangieri FOB 384 New Kendngton PA 15068

The cost of microprocessor, memory, and peripheral devices has plummeted, while the details of computer circuit theory and design have become widely available. In combination, these conditions are enticing a greater number of hobbyists to build and experiment with computer circuits. However, the process of translating published circuits and personal circuit designs into functioning hardware can cfeate unusual problems.

Whether you build a system from the ground up or expand an alreadyexisting system, your initial choice of wiring and prototyping techniques will have a substantial impact on both the effort required and the success of the project. Plugboard systems break a computer system into manageable and easily documented circuit blocks. For rapidity in wiring, assembling, and later modification of the project, wrapped-wire techniques best serve the computer hobbyist.

Wrapped-Wire Connection

A wrapped-wire connection is made up of six closely spaced turns of solid copper wire wrapped, under tension, around square, sharp-edged metal posts. Both the wire and wrappost edges become indented, forming a number of gas-tight contacts with a total resistance of less than three milliohms. An additional turn of the insulated wire at the start of the wrap process prevents wire breakage under conditions of extreme vibration, and also reduces the possibility of a short

152 May 1981 © BYTE PublicaUoni Inc

circuit from the lowest turn of exposed wire to a nearby trace or ground plane on the circuit board.

The wrapped connection is made with a metal tube that has a central hole in one end for a wrap post and a smaller hole (alongside the first) that accepts a piece of wire. In conventional insulated wire wrapping, a piece of wire is cut to length and the ends are stripped of insulation. One end is inserted into the wire hole in the wrapping tool, and the tool is then placed over a wrap post. As the tool is rotated, wire is pulled from the hole at a 90 degree angle and wrapped around the post, creating enough drag and tension to make a good contact. This method requires a separate wire for every connection. It is also possible to connect a niunber of posts with a single unbroken strand of uninsulated wire— a process known as chaining. However, bare-wire chaining is suitable only for installation of ground buses or isolated jumper cormections.

Fortunately, insulated wire chains can be made with special wrapping tools recently introduced by Vector Electroiucs.

Wire-Wrapping Tools

The Vector Electronics model P180 Slit-N-Wrap is a high-speed chainwrapping tool that eliminates wire cutting and stripping. A top-mounted wire spool holds 100 feet of #28 gauge nylon-polyurethane insulated wire (available in four colors). Wire exits

the wire hole, and a sharp cutting edge slits the insulation to expose a portion of bare wire as you form the wrapped connection. The tool is supplied with two spools of wire and a P183 chisel knife and wire-forming tool, for routing wire and nipping ott the beginning end-tail.

The nylon-polyurethane insulated wire resembles magnet wire, and it may be wrapped around an odd-sized terminal and soldered directly through the insulation. (However, you should exercise caution in avoiding the dragging or binding of wire against sharp wrap-post edges.) The thin but tough wire insulation barely increases wire diameter or stiffness, and as a result, the tool maneuvers smoothly on dense wirewrap boards.

A similar high-speed tool, the Vector model P184 Tefzel Slit-N-Wrap, chain-wraps #28 gauge Tefzel insulated wire. This tool is supplied with two 50-foot spools of wire in different colors. Tefzel insulation is relatively thick, allowing carefree wire wrapping and eliminating any chance of a short circuit, but the wire also handles somewhat more stiffly. Both Slit-N-Wrap tools must be rotated clockwise to slit the wire insulation, and both wrap their wire type conventionally.

The Vector P160-2A Dual-Way Wrap-N-Strap is a conventional tool that wraps #30, #28, and #26 gauge wire. Bare-wire chaining or strapping is possible by feeding wire down through the hollow handle. The

Circle 239 on inquiry card. >

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But don't just take our word for it. Visit ttie M icroAge Computer Store nearest you and see ttie difference solutions make. We tiave differences you'll experience witti every time and money-saving idea. Ttie difference ttiat will keep you satisfied now and for years to come!

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Due to the tremendous success of our JAWS I, we were able to make a special purchase of fiist-quality componentB at below-cost prices for |AWS-IB. And we are sharing our cost saving with you. But don't be surprised if the next time you see this ad the prices have gone up substantiaUy. Better yet, order now, and get the best memory on the market at the best price on the market ONE CHIP DOES IT ALL

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■Kil 333 UtchOeld Road, New Mllford, CT 067761

Photo 1: Available wire-wrapping tools include the Vector P180 Slit-N-Wrap, installed in a P160-4R cordless driver unit (left), the P160-2A-1 Dual-Way Wrap-N-Strap (top center), and the P184-Tefzel Slit-N-Wrap (below). The stand (center) displays five different pin-insertion tools. In the foreground (left to right) are the P160-1A Dual-Way unwrapping tool, P178-1 wiring pencil, and the P187 IDC fixture for assembling IDC ribbon cables.

P160-2A-1 wrapping tool is a similar

instrument, but it has a top-mounted spool to hold the bare wire. Both tools offer a solution to the problem of inserting wire (especially the remaining end of a very short wire) into the wire hole. Each tool has a recessed tip with a cross-slot that allows wire insertion without up-ending the tool or fumbling about on the board. The Vector P160-1A Dual-Way unwrap tool has a retractable hood that catches the unravelled wire when you unwrap a connection.

Even chaining can become tedious if you wrap a large backplane or motherboard, but a powered wrapping tool can make this kind of operation less tiresome. Powered wrappers are versatile hand-held units that contain an electric motor and a hollow main spindle that accepts the handles of various manual Vector tools. These electrical tools can make a single wrap in seconds; chains can be wrapped as quickly as the tool is moved to the next wrap post. However, the powered wrappers are bulkier and less easy to handle when routing wire on a densely populated circuit board. The Vector model P160-4R wrapper (see photo 1) is

powered by rechargeable nicad batteries. The newer model P160-4R3 has a hand-fittii\g pistol grip. The P160-4T1, supplied with the P180 wrapping tool installed, is similar in design, but it operates off 110 V AC lines. The battery-operated P184-4T model, and the line-operated P184-4T1 Electro-Wrappers are supplied with the P184 Tefzel wirewrapping tool installed.

Another recently developed wiring technique uses a wiring pencil. The pencil dispenses solder-thru insulated wire from a top-moimted wire spool. Instead of wrapping a connection, you simply loop several turns aroimd a terminal and begin to solder. This technique permits assembly of lowprofile plugboards with low-profile solder-tail sockets. The Vector model P178-1 wiring pencil dispenses either #36 gauge or #32 gauge solder-thru wire and #30 bare tinned wire. The tool is supplied with one 400-foot bobbin of #36 gauge wire (available in three colors).

Wrap Posts and Accessories

Vector can supply wrap posts in many styles, along with DIP (dual inline pin) wrap-post sockets of all

154 May 19S1 © BYTE Publicationi Inc

Circle 302 on Inquliy card.

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Photo 2: Rapid assembly of circuit boards demands insulated-wire strapping or chaining techniques, as demonstrated with the P184 Tefzel Slit-N-Wrap tool. The wide variety of board pins shovm can handle any wiring situation.

sizes. At least four pin styles and several pin insertion tools will be needed to assemble a project. Wrap posts are 0.025 inches square (0.64 mm) and are push-fitted into 0.042 inch (1.07 mm) holes. The T-49 Klip Wrap post has a three-way fork (see photo 2) at one end for support of discrete components that may be snapped in place or soldered. You can instaU this pin with the Vector P156 insertion tool. For soldered installation of discrete components, the T-44 Miniwrap pin has a small slot at one end and is installed with the A13 hand tool. The K-32 J-pin passes through two holes and the short leg is bent to the board. Substitute DIP sockets can be made using these pins.

The Vector T46-5-9 pin is one of several pins that has a crossbar on the shank. The pins are installed with the aid of the P205 insertion tool, and crossbars are aligned to accept female IDC (insulation displacement connector) plugs of ribbon cables. The T46-4-9 pin is similar in design but single-ended, and it passes a cardfinger pad or power plane to the other side of the board. Other single-ended board-feed-thru pins include the T46-4 and T51 pins. Typical of a family of pins having no crossbar, the T46-3 double-ended pin is inserted

with the P133A insertion tool. Use these pins when the laterally extending crossbar pins create a problem. To assemble sockets for small transistors or integrated circuits, you can use the R31 and R32 socket pins. Use the Vector MB45-20 perforated alignment block to back up the board and assure perpendicular installation of board pins. Photo 2 shows useful pin styles and a sample Tefzel-wire chained connection.

Although the use of Slit-N-Wrap chaining tools reduces time spent forming the wrapped cormections, it can be tedious to wire-wrap a circuit that includes hundreds of cormections. Much of the time is spent referring to the schematic and plugboard diagrams, locating the pins on the circuit board, forming and routing wires, and correcting wiring errors. A particular circuit board may have markings (eg: socket pin numbers) that can be helpful in wrapping your circuit, but these marks are quickly obscured on a crowded board with hundreds of closely spaced wrap posts. Correcting wiring errors can be time consuming, as the wire in question is often buried under several layers of wires. Make sure that you are properly oriented when you make the coimections: it will reduce the

156 May 1981 © BYTE PublicaUons Inc

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BYTE May 1981 157

Photo 3: A DIP (dual in-line package) patchboard or breadboard, such as the Vector SIX patchboard, is indispensable to circuit development. This patchboard is top and bottom vArable and am be easily linked to a computer with an IDC ribbon cable.

amount of time devoted to the wiring operation.

To install a chained wire-wrap run correctly, push short lengths of insulation over each post as you identify it, then select the best route for the run. You should begin at the end that allows easy removal of the first wire anchor with a chisel knife. Remove the markers as you proceed, taking care to insert the tool on the marked pin. Check the completed wire nm for errors before you proceed.

Avoid taut wire runs that can result in wire breakage or bent wrap posts. When removing the tool from a wrap post, use the tip of the wrapping tool or the wire-forming tool to mold the wire to the board. An excellent wireforming tool can be made from the wooden handle of an artist's paint brash. Sharpen one end in a pencil sharpener and fashion a screwdriver blade at the other end. Use both the wrapping and the wire-forming tools as you form and route wire to the next wrap post. To reduce crosstalk, avoid bundling wire runs, and approach or pass the wire between socket pins perpendicular to the plane of the pin rows. To begin the next wrap, use the forming tool to press the wire to the board: do this slowly.

using no down-pressure on the first turn. If you use the P180 wrapping tool, start the wrap slightly above an etched plane. Wire breakage rarely occurs, but it is usually the result of a sudden start on a taut wire.

Pencil Wiring

When you assemble a board that uses solder-tail (low-profile) DIP sockets, use the pencil wiring technique. After you chain-wrap the intercormections, solder the looped turns with a soldering pencil heated to a temperature of 750 degrees F. The heat melts the nylon-polyurethane insulation, which allows the solder to bond the connection. The Vector P178-1 wiring pencil is supplied with #36 gauge solder-thru wire, but spools of #32 gauge solder-thru wire and #30 gauge bare wire can also be used.

Orbit the tip of the wiring pencil around the terminal or socket pin, placing the loops of wire somewhat above the board surface. Due to the additional soldering time required to melt the wire insulation, you should use soldering heatsinks to protect delicate components. If this is not possible, tin a portion of the wire before you form the loops (this premelts the insulation). You can obtain

a satisfactory connection by solderwettii\g the loops on one side of the terminal or component post: this reduces soldering time.

You can use the Vector P179WS series of plastic wire spacers to route the wire neatly. The wire spacers are push-fitted into the board and have a number of wire-retaining slots topside. Low-impedance ground circuits may be obtained by running a second or third wire parallel to the first run, or you can pencil-wire the ground bus with Vector W30-4 #30 gauge tinned bare wire. Install discrete components on the T42-1 micro-dips or flea dips.

DIP Patchboard

The DIP patchboard or breadboard is a necessity for developing and verifying circuit designs. The breadboard includes strips and banks of tie points that accept DIP devices, jumper wires, and component leads. Photo 3 shows a Vector SIX DIP patchboard that, with the addition of an IDC 40-conductor ribbon cable, is modified to link up with a TRS-80 computer. Model 51X-GP is similar, but the supporting board has a ground plane. To make a large patchboard, you can install four 51X-GP-2 assemblies in the 43X-4 Multi-Conn chassis. A patchboard (including plugboards) can be assembled on any p-pattem board by inserting the large T66-96 Klip-Bloks, the T45-48 KlipBus, and similar components in any pattern. These unique systems can be wired from either side of the board. Wrap posts pass directly through the tie points to the other side.

A good ground system on the patchboard is imperative. Push long wrap posts through all device ground points and chain-wrap the pins on the bottom side to form a ground grid. Bypass the supply line with a 100 /tF electrolytic capacitor and a 1.0 |tF tantalum capacitor, and bypass the supply pins of all monostables and flip-flops with a 0.1 /iF disk capadtor to ground. One bypass capadtor for every pair of DIP packages should suffice for other devices. Use short jumper wires and keep the wires separated. You can measure the current drain of the patchboard with a meter, but be sure to short out or

158 May im ® BYTE Fublicaliaiu Inc

Circle 393 on Inquiry card.

Let the chips tail where they maj BASIC assure comprehension and competence.

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'J.P. Lamoitier provides the surest way of learning ^ASIC—actual practice. Graduated exercises, each containing a detailed explanation, flowchart and sample run, develop skill and competence rapidly. Applications include mathematics, business, operations research, statistics and more. 256 pp., 194 illustr., Ref. B250, $12.95

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y Rodnay Zaks is a simple yet comprehensive guide to standard and UCSD Pascals: step-by-step presentation with exercises for beginners, complex concepts and extensive appendices for experienced programmers.

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by lacques Tiberghien is an easy-to-read, easy-to-use dictionary containing all the features for most existing versions of Pascal (Standard, Jensen-Wirth, OMSI, UCSD, HP1000, Pascal/Z). Over 180 entries, arranged alphabetically; each includes definition, description, syntax diagram, details of implementation, variations and examples. The perfect reference tool for any Pascal user.

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160 May 1981 © BYTE PubUcaUons Inc

Photo 4: Low-cost open-frame S-100 bus mainframe uses a Vector 8803 motherboard and T169 T-struts. S-100 prototyping boards include the model 8800V in the mainframe, an 8804 Any-Dip board (right), and the 8802 pad board (left). Shown in the foreground (left to right) are the R681-2 plugboard receptacle, KS2-40 female IDC connector, and T169 T-strut. The power supply (rear) bolts to T-struts supporting the S-100 motherboard.

remove the meter when you nm operating tests.

Plugboard Proto Systems

Plugboard systems for the standalone microcomputer or for expansion of an existing system are easily assembled at low cost using Vector card-cage components. You can then add card receptacles to these openframe systems when needed.

An inexpensive S-lOO-bus system can be built using the components shown in photo 4, based on the Vector 8803 motherboard. The board accepts eleven Vector RS681-2 card receptacles that are easily soldered to the hot-tirmed solder-masked board. A portion of the board includes printed-circuit traces for installation of either active or passive bus terminations.

Install the S-100 motherboard on a pair of Vector T169 T-struts (see photo 4) using the insulating spacers that are supplied, and secure it with SC4-28 hex-head screws (these slide into the strut). The BR27D card guides are mounted on the motherboard, on a length of B63-240 ptmched mounting plates. There is

ample room to the rear for installation of an S-100 mainframe power supply for the stand-alone system. The 8803 motherboard mounts directly on the T-struts of the Vector Pak VPl and VP2 deluxe table-top microcomputer cabinets. These cabinets include card guides and a mounting plate for the power supply.

For prototyping or the assembly of system components, select from plugboards optimized for wire-wrapping or soldered-wiring techniques. The Vector model 8800V microprocessor board has a number of wide vertical bus bars on both sides that form the ground and supply planes. The connecting zig-zag buses between the bars accept board feed-thru pins. The supplied heatsink mounts on either end of the board which supports two on-card voltage regulators, one of which is prewired to the power plane. Device sockets are mounted vertically, in four rows and twelve columns, with labeled pin numbers. A coimector for IDC ribbon cable may be installed at either end of the board. The Vector 8804 Any-Dip board (which is similar to the 8800V model in many respects) accepts

circle 256 on Inquiry card.

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162 BYTE May 1981

Circle 191 on inquirv card.

Circle 98 on inquiry card.

Z8000

Photo S: A system bus with fewer than one hundred lines can abo be assembled using standard Vector components. The seventy-two-line combination system pictured here is a typiad example. Primary components include the R636-1 receptacles, a 3677-7 clearance ground-plane board on the wire-wrapped backplane, and a Vector 8004 Circboard in the patchboard area. Plugboards include the model 4066-1 ground-plane board (top left) and the 4493 Any-Dip board with opposing power and ground planes. The system is powered by a Jameco model JE200 power supply.

sockets horizontally, in seven rows

and ten columns, and its IDC cable connector resides anywhere along the top edge of the card. With sockets parallel to the card-finger array, this board allows easy wiring of card buffers and memory arra}^.

use this prototyping system with a smaller user-defined system bus. Lines from the TRS-80 forty-line bus can be assigned so that you can place ground lines that alternate between signal lines, while retaining the same assignment for normal S-100 bus

You can choose from four S-100 plugboards that tend to favor pointto-point soldered wiring. The Vector 8801-1 plugboard has no circuit traces apart from card fingers. Sockets and connectors mount in any position, and you can use Vector T107 punched bus strips to assemble lowimpedance groimd and supply buses. The double-sided 8801 plugboard has one tinned pad per hole that serves as a solderable anchor point for sockets, component wire leads, etc. The double-sided 8802-1 board is similar, but has two holes per pad and vertically mounted sockets. The Vector 8802 board also has two holes per pad, but the holes are plated through to the opposing pad. This unique board favors rapid and reliable anchoring of components, and with minimal risk of pad lifting.

You may find it advantageous to

power-supply lines. Connect the ground on the plugboard, leaving the backplane unaltered. The resulting ground lines shield the signal lines. One prototyping sytem may then serve both the S-100 bus and the foreign bus if you are careful not to plug incompatible cards in simultaneously. The large S-100 boards generally provide more board space per dollar than small cards, but packing a number of smaller system modules on one S-100 card tends to complicate system documentation.

Plugboard systems with a userdefined system bus are easily assembled at low cost and in a manner similar to the assembly of the S-100 system. The system shown in photo 5 uses the R636-1 plugboard receptacle with seventy-two (36/72) contacts and mating BR27-1 card guides. Receptacle wrap posts pass

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Z8001 CPU with memory management circuitry 84K dynamic RAM I/O board: 8 serial ports FDC board: for 4 floppies, sgl/dbl density ZMOS: multi-userZ-tasking operating system Back plane: 15-siots, IVIultibus'" compatible Case: switching power, fans. cage, fixtures Disks: dual floppies (ss: sgl/dbl density) CRT: Dialogue 80'" interactive/edit terminal Gail tor furttier system specifications.

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Dialogue 80'" $1045

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Applications: word processing, data entry, interactive programming, data base inquiry/response/ update, transaction processing, whether on-site or remote. For our system or for yours, this interactive terminal is the perfect match.

Prices: Prepaid or Purchase Order Net 10. Prices subject to change without notice. Warranty: 120 day minimum oh all systems. Interfacing cables free with all systems. 10% down fixes price, guarantees priority. MasterCard and VISA cards accepted.

May 1981 ®. BYTE PubUcaUons Inc 163

MICROMAIL HAS WHAT YOUR SYSTEM NEEDS.

DIABLO

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The Didblo Model 630 Is a lellable, high quoUtr, fullchaiactei serial printer for anyone who Is seeking superior print quality at a low cost This Is the first Diablo printer to offer complete InterchangeobUlty between metal and plastic print wheels. And the sophisticated and dlsceming userdoesnot sacrifice print quality to obtain this TOisatlllty. Every aspect of the Diablo 630 design has been focused on maintaining outstanding print quality. Terminals also hare sell-test extensive internal diagnostics and automatic bldliecUonal piinttng.

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The Anadez Models DF-9500 and DP-9501 Alphanumeric Line Printers ore designed for all printer applications, including those requiring high density graphics. Standard features Include three standard interfaces (SS 232C, Centronics Parallel, and Current Loop), software selectable print sizes Including compressed and expanded print, heavy-duty nine-wire printhead (permits true underlining and descending lower ccse letters), and fast bi-directional printing. The model 9S01 offers sUghtly higher graphics resolution and a sllgbUy slower print speed than the model

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Prices good through June 15,1981

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NBC and DIABLO prices Include forms tractor

To Oidm Send check to MICROMAIL, PO. Box 3297, Santa Ana, CA 92703. Personal or company checks require two v/eeks to clear. Visa/MasterCard accepted. CCD. requires a 16% deposit Handltngi Add 3% to orders less than $750. 2% to orders S751 • $2,000,1% to orders over $2,000. NOTEi Handling charges are waived on orders pre-paid in advance by check. Shipplngi We ship FREIGHT GOLLEeT via UPS or Motor

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through a length of 3677-7 clearance ground-plane board supporting pin rows so that you can plug in an IDC ribbon cable. To create a work area for a patchboard or other circuit, you can add a Vector 8004 Circboard with clearance ground plane, as shown. Alternatively, you can install the 8002 Circboard with interleaved buses for wire wrapping, the 8801 Circboard with buses and three-hole pads for any wiring method, or the 8803 pad-per-hole Circboard. A Jameco JE200 5 V, 1 A power supply fits the system neatly and powers the combination proto system. Plugboards that mate with this system include the Vector 4493 Any-Dip series and the 4066 series boards.

A system with a fifty-six-line bus can be assembled with the R656 plugboard receptacle and the Vector 4610 series plugboards. If you use the R644-3 receptacle with forty-four bus lines, you can choose from numerous plugboards in the Vector 4412, 3662, 3682, and 4494 board series. The 4609 plugboard can be adapted to the external bus system of the Apple II, PET, or Super-KIM machines, either as an open frame set-up or installed in a Vector card cage using the standard mounting hardware.

Give early consideration to the installation of ribbon cable links. IDC cables are readily available, and they come assembled in assorted lengths and a number of lines. You can also use Vector KS2-20 or KS2-40 female IDC plugs to assemble your own cables. The plugs mate with two rows of T49-5-2 wrap posts installed on p-pattem board. Use the P187 universal IDC fixture or its equivalent to press^it the IDC connector to KW220-type twenty-line ribbon cable (use two lengths side by side on the KS2-40 connector). The IDC cable can be used for the links between the computer and proto-system, between plugboards, and to peripherals. You can also use the DIP-plug ribbon cable with male headers that fit standard DIP sockets of most sizes. It is best to use pre-assembled DIP cable. The Vector DIP interconnects are available in lengths of 12 inches (304 mm) and 24 inches (608 nun), and as single- or double-ended cables

P.O. Box 3297 Santa Ana, CA 92703 I Phone: 714/731-4338 ■ I TWX: 910 595 1146

164 May 1981 © BYTE Publications Inc

Circle 257 on Inquiry card.

Wild Hare Software Systems Multiply the Capabilities of Data GeneraFs

RDOS INFOS ^ ICOS DOS

Wild Hare gives Data General users a choice when upgrading to a multi-user environment and eliminates the need to use AOS. Wild Hare makes it easy for you. It creates a true multi-lingual, multi-user environment for your current system. No user software modifications are necessary. There is no need to install a new operating system. And, no expensive hardware upgrade is required.

Features

• Each user is totally independent of all other users.

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• Each user may independently edit, compile, execute and debug programs written in any language supported by RDOS, INFOS®, ICOS and DOS.

• Standard languages supported include: Fortran IV, Fortran V, COBOL,ALGOL. RPG, DG/V. BASIC, PASCAL. MAC, etc.

• All NOVA'S® and ECLIPSE'S® are supported.

• Wild Hare guarantees its software systems on a money back basis.

Wild Hare's Software Gives Data General Users

A Choice!

RO. Box 3581,Boulder,Colorado 80307

NOVA'. ECLIPSE- and INFOS ■,are registered trademarks of Data General Corporation. (303) 494-0221

Circle 435 on Inquiry card.

BYTE May 1981 165

T5€;I-«=IRDSID€

6 South St .Milford, NH 03055 (603)673-5144 TOLL FREE OUT-OF-STATE 1 -800-258-1790

POCKET COMPUTER WITH INTERFACE

$259.

p

COLOR COMPUTER 16K $399

MODEL III 48K $999

TRS-80 COMPUTERS

Mod I, 64K RAM (»26-4002) $3499.00

Mod III, 16K RAM (#26-1062) $919.00

Mod III, 48K RAM (#26-1062+)...... $999.00

Pocket Comp w/lnter(#26-3501 ■»■) $259.00

HARDSIDE40-track Dr{»7-40) $319.00

PERCOM TFD-40 Dr (#7-99) $379.00

PERCOM TFD-100 Dr (#7-100-1) $399.00

HARDSIDE 80-track Dr(»7-80) $449.00

PERCOM Dual TFD-100 Dr(#7-100-2). .$799.00

\

COMM-80 interf (»4-80) $159.00

CHATTERBOX Interf (#4-81) $239.00

DISK-80 Interf, 32K RAM (#4-82) .... $339.00 DISK-80 Interf, 32K RAM (#4-83).... $369.00 BUSY BOX Interl (#4-01) $89.95

LYNX Communications Interf (#i9-60). $229.00 RS Expan Interl 32K RAM(#26-ii40-32) $389.00 16K Memory Kit TRS-keypad(#5-ii02-i) $49.00 16K Memory Kit, TRS-lnterf (#5-1102). .$49.00

Dual Joysticks for Color Comp (#26-3oo8)$24.95 VISTA Model II 8" Disk Dr 1 (#?-4ooi). $939.00 VISTA Model II8" Disk Dr 3 (#7-4002)$1795.00

Color Comp, 4K RAM (#26-300i) $359.00

Color Comp, 16K RAM (#26-3001 + ) ... $399,00 Color Comp, Ext BASIC (#26-3002) $529.00

PERCOM Data Sep (#7-03) $29.95

PERCOM Doubler(»7-07) $199.95

HARDSIDE Ext Cable (#7-02) $15.95

HARDSIDE 2-Dr Cable (#7-04) $29.00

HARDSIDE 4-Dr Cable (#7-05) $39.00

ORCHESTRA-80(#15-03) $79.95

Upper/Lower Mod Kit (#15-02) $24.95

CPU Speed-up Mod kit (#15-04) $45.00

Video Reverse Mod kit (#15-05) $23.95

2- port TRS-BUS Ext (#15-12) $29.95

3- ponTRS-BUS Ext (#15-13) $39.95

TRS-80 Model I Oust Cover Set (#i6-oi).. $7.95 TRS-80 Model I Carrying Case(#i7-2oi)$109.00 TRS-80 Monitor Carrying Case (#17-202) $84.00

CTR-80A Cass Recorder & Cable(#26-i206)$59.95 TRS-80 Model III Dust Cover (#i6-05) ... $7.95

that fit 14-, 16-, or 24-pin DIP sockets.

Bus Terminations

With the aid of a short backplane and short connecting cable to the computer, the plugboard system can usually operate without bus line terminations. However, line terminations reduce line impedances, thereby reducing noise and crosstalk. The line termination consists of pull-up resistors that are placed at one end of the backplane and connected from each signal line to a noiseless regulated-voltage source of 2.6 V to 5.0 V.

The active line termination of the 8803 motherboard is made up of 270-ohm resistors connected to the 2.6 V source. On a pull-down to logic level 0 (approximately 0.4 V), the line termination current is (2.6 — 0.4)/270 (approximately 8 mA), which can be easily handled by standard TTL devices. More than likely, the line drivers of your computer consist of 74LS devices which can drive (sink) 8 mA. This leaves no reserve drive for gates sensing the line, and for this reason you should push-fit the termination resistors on T49 Klip Wrap posts instead of soldering so that you can experiment with lower line-termination currents.

You can conserve supply current by using active line terminations. To obtain line-termination currents of approximately 4, 2, and 1 mA, use 560-ohm, 1100-ohm, and 2200-ohm resistors, respectively. For a smaller system, you can pull up the lines to the 5 V source and compute the termination current based on 5 V.

Plugboard Assembly and Test

Check for errors in the schematic diagram of the circuit, especially in the labeling of device-pin numbers. A pair of diagram sheets are supplied with the Vector plugboards so that you can determine the component and wiring placement for both sides of the board before you begin actual construction. Both sheets should be thoroughly labeled, especially with regard to each of the card fingers connected to the system bus. Observe how the data and address lines are

TERMS: Prices and specKlcatlona are subject to change. HARDSIDE accepts VISA & MASTERCARD. Certified checks and Money Orders; Personal checks accepted (takes 3 weeks to clear). HARDSIDE Pays all shipping charges (within the 48 states) on all PREPAID orders OVER $100.00. On all orders under $100 a $2.50 handling charge must t>6 added. COD orders accepted (orders over $250 require 25% deposit) there Is a $5.00 handling charge. UPS Blue Label, and Air Freight available at extra cost. TRS-SO Is a trademark of Tandy Corp.

166 May 1981 © BYTE Publications Ire Circle 417 On inquiry card.

MODEL I DISK DRIVES

MODEL I PERIPHERALS

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WordStar™ and SuperSort,™ she's a whiz at a lot more than data. Melanie can enter her data... merge, select and rearrange it... and then produce "personalized" mailings.

Discover what Melanie has. DataStar: the microworld's most comprehensive data entry, updating and retrieval system. Send for a free copy of our DataStar demonstration booklet by calling (415) 457-8990. Or

visit your nearby authorized dealer Remember, when you're the star, we're the star.

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INTERNATIONAL CORPORATION

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Circle 249 on inquiry card.

BYTE

C/MOS

SUPPORT CHIPS

AMD 2901

8205

8212

8216

8226

8228

8251

- 12.95

- 13.95

- 3-95

- 2,50

- 2.90

- 2.75

- 4.50

- 6.95

82571AM9517I -8.95 ZBOA SIC - 17.95 8276 - 16J5

FD1791 - 34.%

UART's

AYS-1013 - 3.75

TR1602B - 3,95

AV3-8500 - 1,95

PT)4a2B - 3,25

INTERFACE & DRIVERS

- 1,10

- 2,50

- 2.50

- 2,50

- 2.50

- 2.00

- 2,00

- 2.00

- 2.00

2114L-3 41

4116-2 21L02-3

2102-4 - .90

MK4027-3 - 3.50 MK4096-11 -2.95 TMS4045-25- 6.50 MS4050NL - 3.95 2101-1 -2.45 2107B/5230 -1,75 MM5270 MK4008P 1M7001

ROM'S

2708

2718

2516

2532

B223

82523

82S112

825116

82S123

825126

82S129

82S130

82S131

AM9218C

-3.95 -2.95 -7,95 -6.95 -4.9S -2.95 -3.25 -3.45 -3.95 -6.95

B833 8834 8837

SHIFT REGISTERS

MM 1402 MM 1403 MM1404 MM5013 MM50t6 MM5055 UM5056 MM6067 MM505S

MMsbeo

PRINTED CIRCUIT BOARD

4" X 6" DOUBLE SIDED EPOXY BOARD 1/16" thick $.60 ea 5/*2.60

SPECIALS

4116-3 RAM'S - 8/$24.00

15% ALL 74LS SERIES LEADER OSCILLOSCOPES

WE CARRY A FULL LINE OF HIGH QUALITY, LOW PRICED OSCILLOSCOPES WITH A TWO YEAR WARRANTY. COMPARE PRICE & FEATURES. LB0517 50 MHz D.T. CAL. DELAY $1950.00

OSCILLOSCOPES

LBO-302 10MHz.D.T.,3'CompacI $ 790.00

LBO-30BS 20 MHz, D.T., 3' Portable AC/DC 950.00

LBO-310A 4 MH7, S.T. Rocui. Swoop 2^.00

LBO-507A aOMH7,S.T„5" 610.00

LBO-508A 20 MHz, D,T., 5" 835.00

LBO-511 lDMHz,S.T..5" 420.00

LBO-513 10 MHz, S.T., ImV Sens 495.00

LBO-514 10 MHz, D.T., ImV Sens 645.00

LB0 B1SS 30 MHz, D.T. Cal. DelayocJ Sweep 1,530.00

LBO-520 30 MHi, D.T. w/Dalay Lino 1,100.00

SPBC/ALS GOOD THRU MAY 1981

J CRYSTALS $3.45 ea.

EPOXY GLASS VECTOR BOARD

1/16-thick wIthl/10? spacing 414" X 6%" $1,95

DATEL'SDACOBEQ 8bitDAC-$7.9S

74S89 ISO

74S112 .85

745133 1.40

74S135 1.50

745138 1.!5

745139 1.10

745140 no

743174 74S17B 74S194 74S757 74S2S8 74S260 74S2BO

745373 2

745374 2.

7 WATT LD B5 LASER DIODE IR $8.95

25 watt Infra Red Pulse (SG 2006 equiv.) Lasar DIoda (Spec sheet included) ^24 95

2N3820 P FET S .45

2N 5457 N FET S .45

2N2646 UJT S .45

ER 900 TRIGGER DIODES 4;$1.00

2N 6028 PROG. UJT S .65

TTL REED RELAY ~ SPST5V20ma $1.00

CLOCK CHIPS

MM5387AA $5.95

MM5314 94:75

MME3t6 »4.96

TANTALUM CAPACITORS

.22UF35V 5/SI.OO 10UF10V-$.4O

.47UF35V 6/$1.00 22UF 10V -$ .30

.68UF3BV B/$1.00 15UF16V 3/Sl.OO

1UF36V 6/91.00 30UF6V 5/$1.00

2.2UF20V 691.00 33UF20V S 60

3.3UF20V 4/91.00 47UF20V $ 86

4.7UF16V 5/SI.OO 100UF15V S 70

6.8UF35V 3/$1.00 150UF15V ; 95

SANKEN

AUDIO POWER AMPS

SilOIOGIOWATTS .. $ 7.50 Si 1020 G 20 WATTS .. $11.00 Si T030G 30 WATTS .$13.50

Si 1050 G 50 WATTS .$25.00

200 PRV 1A LASCR .95

RS232 CONNECTORS

DB 25P male $3.25

DB 25S female ... $4.25 HOODS $1.50

2,000 MHz 4.000 3,000 MHz 3,57 MHz 5.000 MHz 6.000 MHz

6,144 MHz a,OO0MHz 10.000 MHz 18,000 MHz 1B,432 MHz 20.000 MHz

RIBBON CABLE FLAT (COLOR CODED) #30 WIRE

16cond. - ,40/perfoot 40cond. - .75/perfoot BOcond. - .90/par foot

MINIATURE MULTI-TURN TRIM POTS 100,5K. 10K,20K,250K, ... S.75each.

NO, 30 WIRE WRAP WIRE SINGLE STRAND

100' $1.40

ALCO MINIATURE TOGGLE SWITCHES

MTA106SPDT S1.05

MTA206DPDT S1,70

MTA20ePDPDTCENTROFF S1,B5

MSD 206 P-DPDT CENTER OFF LEVER SWITCH SI ,85

SCR's

600

1,5A 6A 36A IIOA

3,60

15.00

TRIAC's

PRV I 1A llOA laA

2.00

2.75

1.30

FP 100 PHOTO TRANS S .50

RED, YELLOW, GREEN OR AMBER LARGE LED's .2" 6/Sl ,00

RED/GREEN BIPOLAR leg's S .55

MLED92RLED $ .75

MRD14B PHOTO DARL.XTOR S .75

TIL-1180PT0-IS0LAT0R $ ,75

IL-5 0PT0-IS0UT0R S ,80

1 WATT ZENERS: 3.3,4.7, 5.1, 5.6,6.8,8,2,9-1,10.

12.15,18, or 22V 6(S1,00

PRV

1A

3A

12A

50A

125A

240A

100

.06

.14

.35

.90

3.70

8.00

200

.07

.20

.40

1.30

4.25

12.00

400

.09

.26

.65

1.60

6.60

15.00

600

.11

.30

.80

2.00

8.50

18.00

SOO

.15

.35

1.00

2.50

10.50

22.00

1000

.20

.46

1.25

3.00

12.50

26.00

IN4148(IN914) .■15/$1.00

.1 or .01 uf 25V ceramic disc. caps. 16/$1.00, 100/$5.00

7 SEGMENT DISPLAYS

FSC 8024*4 digit

CCa^display.... $5.95

FND503C.C..B'.. $ .85

DL-704-.3''C.C.... $ .85

DL-707C,A, .3" DL747 C.A..6" HP3400.8''CA. HP3405.8"CC.

,. $.75 ,.$1.60 , $1.96 , $1.95

TRANSISTOR SPECIALS

2iyi307PNPGETO-5 .

2NilO'lAPNPGETO-5

HEPG6014 - PNPGETO-3 . .. TIPI21 - NPMSiSWITCHIWG 2N6233 NPN SWITCHING POWER. MRF-8004 a CB RF TRAMSISTOR NPN

2N3772 MPNSiTO-3

2M4908 PNP Si TO-3

2N50e6PNPSiTO92

2N3137 NPN Si RF

2M3919NPN Si TO-3 RF

2N1430NPNSiT&5

2N3767 NPN SIT&66

2N2222 NPN SiTO-lB

2N2907 NPNSITO-18

aNSOBBNPN Si TO-3

2N3904NPN SITO-92

2N3906 PNPSlTO-92

2N5296NPNSITO-220

2N6109 PMPS.TO-220

2N6308NPNSiTO-3

TiP31BNPN SiTO-220

TIP32B PNP SiTO-220

TIP 34 PNP Si

TlPPNPSiU84

S 40 »

,, » ,70 5/«1.00 4/»1.«l

7400

7401

7402

7403

7404

7405 7406 7407

7408

7409

7410

7411

7412

7413

7414

7416

7417 7420

7425

7426

7427 7430 7432

7437

7438

7440

7441

7442 7445 7446 7447

TTL IC

7472

7473

7474

7475

7476 7480 7483

7485

7486

7489 - 1

7490

7434 - ,6

7495 - .6

7496 - .6 74107 - .3

74121 - .3

74122 - ,3

74123 - .4

74125 - .4

74126 - 4 74145 - .7 7414S - 1.5

74150 - 1,1

74151 - ,6 74153 - .5 75154 - i.r 74155 - .7! 74157 - .C!

74160 - B!

74161 - Bl

SERIES

35 74162

35 74163

42 74164

49 74165 45 74166 45 74167 60 74170 75 74173 4Z 74174 60 74175

50 74176 55 74177 50 74)B050 741Bl 60 7419060 74191 60 74192 .35 74193 ,35 74134 39 74195 42 74196 45 74197 45 74279 .75 "325 50 ""65

74367

74368 74390^ 75325

75491

75492 _8T9e

9312 9601

FULL WAVE BRIDGE

PRV

2A

6A

2SA

100

1.40

200

.80

1.30

2.20

400

1.00

1.65

3.30

600

1.30

1,90

4,40

DIP SOCKETS

BPIN

.17

22 PIN ,30

UPIN

.20

24 PIN .35

16 PIN

.22

28 PIN .40

18 PIN

.25

40 PIN ,60

74LS SERIES

SFC 3301 - 50 PRV 30A FAST RECOVERY DIODE (35ns) ..$2.25 20KV250MA DIODE $1.90

SILICON POWER RECTIFIERS

74LSD1 74LS02 74LS03 74LS04 74LS05 74LSD8 74LS09 7<LS10 74LS11 7aLS12 74LS13 74LS14 741515 74LS20 74LSH 74LS22 74LS!6 74LS27 ~ 74LS2B 74LS30 74LS32 74LS37 74LS3B 74LS40 74LM2 74LS47 74LS51 74LS54

.25

74LS74 - ,85 74LS76 - ,75 741578 - ,4B 74LSB3 - .95 74LS8E - 1.10 74LSB8 - ,45 74LS90 - .90 74LS92 - ,90 74LS93 - ,90 74LS96 - .90 74LS107- .47 74LS109- ,45 74LSI12- .45 74LS113 - .45 74LS114 - .55 74LS123 - .75 74LS125 - .90 74LS126 - .90 74LS132 - .60 74LS136 - ,aO 74LS138 - .75 74LS139- ,70

74LS151 - 1,19 74LS1E3 1.13 74LS1bb - \ Itl 74LS16li - 1 19 74LS157- .95 74LS160-1.00 741S161 - 1.00 74LS162-1.0O 74LS163-1,00 74LS164- 1.00 74LS168-1.25 T4LS1Ba-1.76 T4LSI70- i,70 74LS173- 50 74LSI74-1.00 74LS176-1.00 74LS181 -2,60 741^19-J J6 74LS1ST-t,1E 74LSt82- .90 7415163- .90 74LS184-1.10 74LS19S- -90 74L5196-I.D0 74LS197- 90 74LS240 - 1.60 74LS241 -l.M 74LS242- 1.ea 74LS243 -1.60 74LS244 -1.60 74LS24S-2,25 74LS261 - 1.29 74LS263- 1,00 74LS257- .90 74LS2Ba- .90 74LS259- 1.50 74LS266- .70 74LS273 - 1.25 74LS279 - ,70 74LS283 - .BO 74LS290 - .90 74LS293 - .80 74LS365 - .80 74LS367 - 80 7JLS368- -BO 74LS373 74LS375 74LS377- 1, 74LS3B6 74LS393 74LS670

LINEAR CIRCUITS

LM307 LM308 LM324

U*«4e - .90

LM35e

LM361 LM377

LMja2 - an

LM388 - .BU LM387 - 1.2E LM6S3 - 2.2E LM565 - 45 LM653 - ,85 565 - .Hb

- 1.76

.M1810 -.M1BB9 CA75B CA3018 CA3046 CA307B CA3D80 CA30B6

REGULATORS

LM317T 92,B0

LM337 $2.60

323K-eV3A «G,76

79HGKC-5VBIEA $6,K

723 S .50

320T5, 12, or 15V SI.10

LU306G S .75

340K-12,16or24V.S),B0 340T-6, 6. 8.12,15

1Bor24V 51,10

320M5 S .75

LAS1412-12V3A S3.95

POSTAGE ADD 10% FOR ORDERS UNDER $20.00 RATES ADD 5% FOR ORDERS BETWEEN $20.00 AND $50.00 ADD 3% FOR ORDERS ABOVE $50.00

TERMS:FOB CAMBRIDGE, MASS. SEND CHECK SEND S.25 FOR OUR CATALOG

OR MONEY ORDER. MINIMUM TELEPHONE, FEATURING TRANSISTORS Er

C.O.D. PURCHASE ORDER OR CHARGE 420.00 RECTIRERS. 146 HAMPSHIRE

MINIMUM MAIL ORDER S&.OO. ST., CAMBRIOaE, MASS, 02139

grouped together in certain areas—it can help you determine the optimum placement of the associated integrated circuits. Use the plugboard itself for the preliminary layout of sockets and other components. Determine the locations of board feed'-thru pins and all discrete components: don't wait until after you have begun to wire the board. It's a good idea to include extra ground feed-thru pins and to leave one socket position open near the card fingers for future additions. Draw the socket outlines on both layout sheets, show the positions of feed-thru pins and discrete components, and label them accordingly. Check any prewired card finger or voltage regulator position and make any changes by cutting traces.

Install all board pins, but omit the sockets so that you can use the board backup block. Insert T46-2-9 doubleended wrap posts in all card fingers, driving them in from the copper side of the pad hole. Though pins make excellent electrical contact with the pads, the connection can become erratic if you loosen or rock the pins excessively. Check for continuity with the ohmmeter, and solder if necessary. Many of the wire-wrapstyle plugboards are designed to accept the disk bypass capacitor by direct soldering to the etched planes. Install and solder the capacitors before you install the sockets.

Secure the sockets to the board using 5-minute epoxy cement. Press an index card against the tips of the wrap posts associated with the card fingers on the wiring side of the board. Mark and label the impressions with bus assignments, for reference when wiring. Label an unmarked socket position using MSlOA pin-marking strips. Begin by chainwrapping the ground circuits to further reduce ground-return impedance. Wire the supply lines next and, as the last step, install any wiring which may be altered. Record your progress on the schematic diagram as you install and verify each wire run.

Before you install any integrated circuits, use the ohmmeter to verify all wiring topside from card fingers and from socket to socket. Check for

0

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168 May 1981 © BYTE PubUcations Inc

Circle 103 on Inquiry card.

Corvus Lowers the Price of Admission to the Winchester Club.

Here's the price breakthrough you've been waiting for on Winchester disk systems. It's our new 5'/<-inch 5-million byte Winchester that adds cost effective mass storage to over 15 of the most popular microcomputers. Now everyone can enjoy the improved reli ability, increased storage capacity, and faster speed of sealed-environment Winchester technology.

You can start with 5 million bytes, then expand the system with up to three add-on drives of 5,10, or 20 million bytes. Our 5 million byte system has all of the advanced features of the larger capacity Corvus systems, ^

including our low cost MIRROR backup and multi-user CONSTELLATION network that allows up to 64 computers t share the Corvus data base and peripherals such as printers.

Want the full story? Contact your local computer store.

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bus- and supply-line short circuits. Insert a milliameter in the power supply line and energize the board. Check voltage-regulator outputs and voltage distribution. With the power off, insert integrated circuits one by one and observe the expected increases in supply current. If all is well, connect the ribbon cable to the proto system and check the voltages at the other end of the cable. Take care that the proto system's power supplies do not feed directly back to your computer!

At this point, the wise experimenter will perform static tests on at least a portion of the board logic (eg: port and memory decoders). Use jumper wires to program the input logic and verify the output. A patchboard with the entire system bus laid out and labeled on Klip Block linked to the system by ribbon cable is a handy aid for conducting static tests. These tests detect wiring and design errors, as well as defective integrated circuits.

Always turn off all power when in

You can extend the usefulness and data entry speed of your TRS-80 by giving it the graphics and menu capabilities of the Bit Pad One digitizer.

With the Bit Pad and proper software, you can generate schematic diagrams; describe sales curves to your computer; enter alphanumeric information by merely touching printed letters on a menu, or enter order or

inventory information by merely checking boxes on printed forms.

Bit Pad One, complete with stylus, specially designed plug-in TRS-80 interface and power supply cost just slightly over $1,000.

If you don't have a digitizer, you are restricting your TRS-80's abilities. We'll gladly send you a list of distributors who have the Bit Pad One.

^ ' corporalton

35 Brentwood Avenue, Fairfield, CT 06430, (203)384-1344

Now, Bit Pad One" digitizer malces it easy to add grapliics capabiiity to your TRS

serting or removing cormectors and plugboards. Cormect the untested ribbon cable and proto system to your computer, but do not install the plugboards. If your computer fails to function, look for line shorts. Another possible culprit is the ribbon cable capacitance (or the cable may be picking up noise). Always use very short cables and be prepared to experiment with several lengths. As the final and most crucial test, insert the plugboard in the proto system for dynamic on-line tests. The most frequently encountered problems are the result of wiring errors or omissions, erratic or defective integrated circuits, and contaminated and erratic coimectors.

An erratic integrated circuit device is difficult to pinpoint, but it can be forced to reveal itself. Allow the system to warm up thoroughly, and attempt to reproduce the observed erratic behavior. Then, spray each suspected device with integratedcircuit cooler. In many cases, this will temporarily restore the system to normal operation and isolate the troublesome component. Another approach is to substitute suspect integrated circuits 'with those that you know are reliable.

Once you resolve the frustrating circuit problem, you will gain a far greater understanding of the microprocessor, logic circuits, and test techiuques. So start experimenting with computer hardware circuits made simply by wire wrapping and a plugboard system. It will lead to greater enjoyment of your hobby. ■

Notice of Omission Due to a processing error the Lanier Business Products ad which appeared on page 27 of the April Byte had no Reader Service Number.

For more information regarding their "no problem trial offer" circle 475 on the inquiry card in this issue.

Speeding Up TRS-80 Graphics

Ronald Bobo 3246 Gravois St Louis MO 63118

John KnodercT The Software Center 51 Florissant Oaks Shopping Ctr Florissant MO 63031

Many TRS-80 owners have probably, at one time or another, experimented with using DATA statements to store graphics information. This method can be highly efficient, but there's a catch. It is possible to store graphics as data in several different ways. Which is best?

In this article, we will examine some of the methods of storing a screen image as DATA statements, and, later, of recreating it on the video screen. Listings 1 thru 13 show the evolution of successively complex techniques.

In most cases, we will start with a picture onscreen (as provided by a run of listing 1). Many of the simpler sketching programs for the TRS-80 don't provide any way to store the images to disk, and the screen-reading programs used as examples in this article can be appended to a sketching program that will allow you to save your work. Let's look at the first method of saving screen images.

POINT Graphics

Every cell (graphics point) on the TRS-80 graphics screen can be turned

on by a SET statement or turned off by a RESET statement. This method is used in listing 1 to draw a picture on the TRS-80 video screen. Another

Interested readers can call The Software Center at (314) 838-7785.

TRS-80 Level II command, POINT, returns a 1 or 0 based on the value of the cell given by the x (column number) and y (row number) parameters of the POINT statement.

The easiest way to store the video screen would be to examine and write an (x, y) number pair for each cell that is shown. Unfortunately, this is both time consuming and wasteful of disk storage. Due to the nature of most drawings, they are more easily approached as a series of horizontal

By PEEKing the appropriate memory locations, we can represent the contents of the screen as exactly 7024 numbers.

lines; this is done in listing 1 where a horizontal line of cells is SET to screen inside a do-loop that varies the X (column) coordinate of the SET statement. We can store each line of cells as a triad of numbers: y (row) number, beginning x (column) number, and ending x (column) number. Then we can later read the triad and recreate the line by executing a SET statement within a do-loop.

Listing 2 illustrates this process by creating the disk file of triads (lines 11000 flmi 11050), closing it (line

11060), then opening it again and recreating the picture from a cleared screen (it does this by reading the disk data file in lines 12000 thru 12020, as discussed above). The data in this data file will be used by listing 3.

Data Files and POKE Graphics

To use these data files in other programs, the disk file of numbers must now be converted to DATA statements. However, you won't have to type them on the keyboard. Listing 3 will read the disk file from listing 2, convert the numbers to DATA statements complete with line numbers, and put them back onto disk in ASCII format, ready to be merged with a BASIC program.

Now that the numbers have been reconfigured as DATA statements, they can be merged with a short program that will use the DATA statements to set the graphics. This method is a bit faster than reading the data from a disk file. Listing 4 includes the DATA statements (lines 1905 thru 1960) generated by listing 3 (which contain the data generated by listing 2). Lines 100 to 130 read the data and set the graphics. Lines 200 to 210 generate hardcopy of the information on the screen for conversion to DATAPOKE statements. Line 300 creates a file and stores the data on disk.

Listing 4 creates (in line 300) a new Text continued on page 176

May 1981 © BYTE Publications Inc 171

REQUEST

U.S.A. BEATS I.B.M. TO MARKET WITH TRUE RELATIONAL DATA BASE!

On Feb. 1, 1981, I.B.M. announced a relational data base for 370/3033 users... U.S.A. introduced REQUEST™ 3 months earlier for the APPLE & PET!

DATA BASES ARE A DIME A DOZEN!

Flip through any computer magazine and one company after another will promise you that their product is the ultimate in data- base programs.

WE DON'T TAKE THEIR WORD FOR IT!

A recent ad for data base management even provided it's own comparison checklist to prove that their data base surpassed all other data bases on the market today.

"COMPARE...DON'T TAKE OUR WORD FOR IT," THEY SAID.

WE DID

COMPARE

21

UNTIL TODAY THERE WERE MORE THAN 2b(bATA BASE MANAGERS FOR THE APPLE I

NOW THERE'S ONLY ONE!

THE APPLE DATA BASE MANAGER YOU'VE BEEN WAITING FOR

It you want an easy-to-use. flexible, and versatile data base nnanager, you have a choice of one. DB MASTER from Slonewaie Microcomputer Products - soon to become the standard by which all others will be judged.

But don'l just take our word for it. Compare the many advanced features of BB MASTER with the data base manager you're now using. Or tor that matter, compare it with any data base manager on the market. No one will even corrie close,

DB Ri^HWES'^gpORj GENERATOR: MASTER fJBMS

FEATURES

FILING SYSTEM:

Maximum search time to find any record by its primary key

True ISAM file system with multi-field

primary keys YES

Multiple secondary keys for rapid

access (5-7 seconds) to records by any field

Primary & Secondary keys maintained automatically—no need to rebuild keys after adding records YES

Ii^aximum record size (bytes! 10SO

Maximum number of fields,'record ,. 100

Handles files with more than one

diskette of data YES

Custom disk operating system (DOS) for faster data retrieval and program chaining YES

User-designed screen formats

Up to 9 screen "pages" per record..,

Ten field types, including dollai/cenis, phone & social security number, date, etc

Automatic data compaction for

increased disk siorage capacity.

Wild card, partial string, range and Boolean search capabilities..,

Dynamic prompting (tm) - lists all

available functions on screenno need for guick reference card.

Password file protection

Four function calculator mode

Daily update lists lor printout of all records added/edited on any day or range of dates YES

UNDER ^Jpfer 3 sEcs_Lse,.c,.

Send reports to screen or printer, Sort on up to 6 fields at a time ,. Column subtotals and totals

Yes

YES Yes (approxisec)

Yes 4064

ma:

Yes

Subtotal and page breaks

Up to 24 computed fields per report

Up to 9 lines of column titles ..,,, Up to 9 lines for each record YES

too

YES YES YES

YES YES

YES

Maximum number of fields per report Code fields - store short cories, print

long descriptions YES

Comment lines and footnotes YES

Comment fields for printing labels or

headers within each record ,,. YES Summary only reports YES

Yes^ , YMtie) Yes_

Yes

m09)

Yeslie) Yes(l6)

j999

Yes Yes

s,

es

AND REQUEST ™ GIVES YOU ALL THESE EXTRAS

■ Multiple formats for mailing labels

■ REQUEST'" can be used with a modem

■ On the APPLE'" REQUEST'" is compatible with 80 column boards

■ High level query language or screens used to form query

■ Query library stores executive queries for Run-On-Demand

■ REQUEST'" will interface with Source'", VisiCalc'", and word processing packages

■ Disks are readable and copyable by normal DOS

ONLY

$225

DEALER INQUIRIES INVITED

While a custom DOS is nice for speed, it does place the user in a bind, since it makes the data incompatible with APPLE'S DOS & other software. REQUEST'" is fully compatible!

REQUEST'" utilizes a sophisticated screen generation algorithm to produce screens pleasing to the eye and easy to use, AUTOMATICALLY.

REQUEST'S'" additional search functions include:

■ context search

■ arithmetic expression evaluation search

■ multi-field reiational search

Yes

REQUEST & THINKER , United Software of Ame

ire irade marks of

THINKER

THE IIMTELLIGENT ACCOUNTIIMG SYSTEM

THINKER™ & REQUEST™ CAN BE USED SEPARATELY OR TOGETHER AND DATA MAY BE INTERCHANGED.

1

J ■

THINKER'S'" ADDITIONAL FEATURES INCLUDE —

■ Compatible with REQUEST™

■ Customized access to THINKER™ data via REQUEST'"

■ Relational analysis of THINKER™ data via REQUEST™

■ Utilizes a 9 digit ZIP Code compatible with Canada & Europe

■ Passw/ord protection for system security

■ Daily audit trails for system integrity

■ Dynamic system configurator will expand data to additional drives when needed, AUTOMATICALLY!

■ Employs industrial psychological approach to achieve superior human engineering.

Introductory Price

$495

SUPER KRAM IS REQUIRED FOR EITHER REQUEST OR THINKER AND IS AVAILABLE FOR $175

Look for the RED-WHITE-BLUE United Software Display at your local computer dealer, or send check or moneyorder. plus $3.00 shipping to:

= ^ UNITED

E^^^^^ SOFTWARE

750 THIRD AVE. AMERICA NEW YORK NY 10017

(212) 682-0347 Telex 640055

SOFTWARE THAT THINKS FOR ITSELF

Before The THINKER™, microcomputer business systems have fallen short in two distinct areas: FLEXIBILITY and INTEGRATION. Every business is different and requires software to be pre-set to fit its own particular needs. A nip here, a tuck there, and files are extended to where the business was expected to be. . . But, a single file too short can cause the system to fail, or a single file too long wastes costly disk space. The THINKER™ takes the guess work out of your business data processing by thinking for you.

EASY TO USE-FULLY INTEGRATED ACCOUNTING SYSTEM

The THINKER'" consists of 6 comprehensive interactive modules, with ail transactions applied immediately and the results are instantaneously accessible. They are;

• ACCOUNTS RECEIVABLE • ACCOUNTS PAYABLE

• SALES ORDER ENTRY • PURt)HASE ORDER ENTRY

• INVENTORY CONTROL • MAILING LIST (General Ledger available in June)

FLEXIBILITY- SOFTWARE THAT GROWS WITH YOUR BUSINESS

The THINKER™ utilizes the DYNAFILE™ Keyed File Allocation Scheme which dynamically manages file length and records to meet the businessman's needs and will automatically extend itself to work on hard disks without any program modification. No disk space is wasted because the system automatically recaptures space when records are deleted. DYNAFILE™ utilizes a sophisticated indexing scheme, allowing direct access to any record. Machine language programming insures DYNAFILE™ speed, reliability, and integrity.

The THINKER™ is currently available for 6502 based microcomputers. 80 column PET/CBM Computers 80 column Apple Computers

circle 2 on Inquiry card.

BASF "FLEXYDI5K"... * Superior Quality data storage medium. Certified and guaranteed 100% error free.

SINGLE SIDED-SINGLE DENSITY

51/4" or 8" Diskettes 10/$24

5V4" or 8" Vinyl Storage Pages 10/$5

MAXELL- DISKETTES Tlie best quality diskette money can buy. Approved by Shugart and IBM.

Sold only in boxes of 10

5", 1 side

8", 1-side

5", 2-side

8", 2-side

All MAXELL DISKETTES ARE DOUBLE DENSITY

LIBRARY CASE... 3-ring binder alburn. Protects your valuable programs on disks Fully enclosed and protected on all sides. Similar to Kas-sette storage box.

Library 3-Ring Binder $6.50

5Vii" Mini Kas - sette/10 $2.49

8" Kas-sette/10 $2.99

DISKETTE DRIVE HEAD CLEANING KITS, Prevent liead crashes and insure efficient, errorfree operaiion.

5 .;" or 8' $19.50

SFD CASSETTES

C-10 Cassettes 10/$7

(All cassettes include box & labels

Get 8 cassettes,C-10 sonic and Cassette/8 library album for

only ....$8.00

(As illustrated) ^^^^

HARDHOLE Reinforcing ring of tough mylar protects disk from damage 8" Applicator $4 5VS" Applicator $3 50/8" Hardholes $8 5Vi" Hardholes $6

VISA • MASTERCHARCE • MONEY ORDERS CERTIFIED CHECK • FOR PERSONAL CHECKS ALLOWTWO WEEKS • CO.D. REQUIRES A10%

DEPOSIT • CAL. RES. ADD 6% SALES TAX MIN $2 SHIPPING & HANDLING • MINIMUM ORDER $10 • SATISFACTION GUARANTEED OR FULL REFLJND

Listing 1: TRS-80 graphics program using the traditional SET and RESET graphics.

10 CLStCLEAR 200

20 FOR X=50 TO 951 Y = 12! SET < X > Y) ! NEXT! FOR Y = 13 TO 32; SET < 50 . Y ) t SET (95. Y ) ; NEXT 30 FDR X=2a TO 50 ! Y=22 : SET ( X . Y ) ! NEXT I Y = 22 t FOR X=37 TO 13 ! SET (X , Y) t Y=Y-1: NEXT 10 FOR X=1't TO 19iSET<X,Y) ;Y=11:NEXT!F0R Y=22 TO 29 !X=28 !SET (X. Y > ! NEXT 5F0R Y=29 TO 30:X=27:SET(XfY)8NEXT;FOR Y=27 to 2aiX=29:SET<Xi.Yj:NEXT:F0R Y=26 TO 27IX=30{S ET<XrY);NEXT

50 FDR Y=2S TO 24! X=31!SET (Xi Y) SNEXTtSETOl 125) tFQR X=32 TO 38SY=24!SET(Xf Y> SNEX T:SET(10,23):SET('H.21)!SET<16r21)!Y=Z5JFQR XMZ TO <17:SET(X( Y)! Y=Y+11NEXTIF0R Y =23 TO 30:X=ia!SET(X.Y):NEXT

60 Y=25:FQR X=38 TO lltSETtXrY) :SET(X+1>Y> :Y=Y+1 JNEXT:F0R X'IS T074!Y=32iSET(X»Y >tNEXTSY=3i:F0R X=76 TO SStSETCX.Y)!SET(X+1»Y):Y=Y-1tNEXT

70 FOR X=83 TO 90!Y=21;SET(XfY);NEXT!Y=Z5!F0R X=90 TO 91:SET(X.Y);SET(X+1.Y);Y=Y +1:NEXT!F0R X=96 to 97:Y=31!SET(X.Y):next

BO FOR X=33 TO 36:Y=27:SET(XfY)!NEXT:F0R X=85 TO 88:SET(XfY);NEXT!FOR Y=30 TO 32

;X=30iSET(X.Y) JNEXT:Y=3a:F0R X=30 to 32iSET(X>Y>:SET<X+lFY)SY=Y-i;NEXT

90 Y=28;F0R X=36 TO 38:SET<XfY):SET<X+1fY)!Y=Y+1:NEXT;Y=32SF0R X=30 TO 33SSET(Xf

Y);set(x+1fY)!Y»Y+i;NEXT;FOFi! x=33 to 3a;y=35:set(x.y);next

100 y=31!for x=36 to 3a!SET(XFY)!set(x+i>y) :y=y-i:next:for y=30 to 32:X=39:BET(X rY) !next:x=3i:y=301set(XfY) ;set(x+i fY) :set(33f31 ) :set(36f31 ) :x=3i:y=32!Set(XfY) :

SET(X+1fY)

110 FOR Y=30 TO 32:X=82:SET(XfY)!SET(X+9fY):NEXT!Y=30!FOR X=82 TO 85:SET<XrY);SE T(X+lFY)iY=Y-liNEXT:Y=32!F0R X=82 TO 81; SET (X f Y) tSET < X+1 f Y )! Y=Y+1: NEXT : FOR X=85 TO B8;Y=35!SET(XFY)iNEXT

120 Y=31!F0R X=a8 TO 90 tSET <Xf Y ) ! SET<X+1 f Y )Y=Y-1 tNEXT t Y=28; FOR X=88 TO 90:SET<X

, Y) :sET(X+i fY) ;y=y+i:next:for y.=S6 to 87iY=3o:sET<XFY) ;y=32:set(XfY) •.next:sei (bs

f31):SET<BaF31)

130 X=55;Y=15!SET(XfY) :SET<XFY+l):SET<X+l.Y+2)iSET(X+lFY+3)iSET<X+2FY+1) iSET(X+2 FY+5)SSET(X+3»Y+6)JSET<X+1fY+S)tSETCX+t.Y+'l):SET(X+5»Y+3> tSET(X+5.Y+2){SET<X+6»Y +l>iSET<X+6FY>

110 FOR Y=15 TO 2i:X=65JSET(X.Y) :NEXT:F0R X=69 TO 735 Y=l5JSET<XtY> INEXTtFOR Y=14 TO Z1:X=71:SET(XfY) JNEXTSFOR X=77 TO 81!Y=15SSET(X.Y):Y=21ISET(XFY):MEXTtSET(78 f18):F0R Y=15 to 2i:X=77!SET(XFY)iNEXT

150 FOR Y=1S TO 21 iX=85SSET(XfY> tNEXTtY=«18:F0R X=86 TO 89iSET(XiY.) !Y=Y-HNEXT;Y= 18:F0R X=a6 to 89:SET(XfY)iY=Y+l!NEXT

160 FOR Y=21 TO 29;X=S5;SET(XfY) !SET<X+1fY) :SET(X+9fY) :NEXT!Y=25:F0R X=60 to 62!

bet(XfY>:sET(X+iFY)tY=Y+i:NEXT:

170 FOR Y=25 TO 28:X=68iSET(XfY)tNEXTtFOR X=69 TO 71iY=21iSET(XfY)!Y=29:SET<XfY) !NEXT:SET(7ZrZ5>:8ET(72t28>JSET<71f29)

180 FOR X=l TO 1500;NEXTSPR1NTB61fSTRING«<60f" ■)tPRINTB128FSTRING«(60f' MtFOR X=5 TO 125:Y=0!SET(XfY);SET(XfY+1)!Y=17:SET(XfY>J8ET<XfY-1);NEXT!FOR Y = 0 TO 17:X

^5:set(XfY>:set(x+1fY):set(x+2fY):next

185 FOR Y=0 TO 17!X=125!SET(XfY)!SET(X-lfY):SET<X-2fY>:NEXT!FOR X=l TO lOOOiNEXl

Listing 2: Program to read data directly from the screen memory and store it to the disk as mmAers representing a series of horizontal lines of graphic dots.

11000 11010 11020 11030 11010 11050 11060 12000 12010 12020 20000

20010

20020 650 00

OPEN'O" fIf 'GRAPHIC/DAT' !FORY=OTQ17!X=-1

X=X+1!IFX>127THEN11060

IFPOINT(X»Y)=0THEN11010

X1=X

X=X+i:iFX>127ORf>OINT(X.Y)=0THENPRINT»lFY"F"Xl'F"XSCOTO1101O

GOTO11010 NEXTY!CLOSE

DPEN'I-,1,'GRAPHIC/DAT'!CLS

C=C+1;IFEOF(1)=0THENINPUT*1fYfX1fX2;FORX=X1TOX2!SET(XfY)!NEXT!GOTO12010 GOTO1202D

REM—ORIGINAL GRAPHICS ROUTINE FROM A SKETCH BY

KARL WILLIAMSOt>l. DVERLANDf MO. SET AND RESET

GRAPHICS BY RON BDED, REM—ALL OTHER PROGRAMMING IN THIS SERIES BY JOHN KNODERERf COMP-U-TRSf 51 FLORISSANT DAKS SHOPPING CENTERF FLORISSANTf MOf 63031 REM—LINES 11000 TO 11060 CONVERT SCREEN TO VALUES Y, XI AND X2 AND SEND TO DISK. FOR USE IN LINE "FOR X=X1 TO X2!SET(XfY) :next'

REM—LINES 12000-12020 TEST THE NUMBERS CREATED BY llOOO, 'TWO

Listing 3: This routine reads the data file generated by the program in listing 2 {and subsequent listings) and creates an ASCII file containing BASIC DATA statements.

13000 CLEAR9999!0PEN'I'fIf "GRAPHIC/DAT" JLN=1900:OPEN"O"»2f"GRAPHIC/ASC

13010 LN=LN+5!X«=STR$(LN)+' DATA"

13020 IFEOFd)THENPRINT*2fLEFT$(X$fLEN(X*)-1):PRINTX»CHR»<8)tCLOSE:END

13030 INPUT*1fY!X$=X»+MID*(STR$<Y).2)+'.":IFLEN(X*)>237THENPRINT*2.LEFT$(X»,LEN(

X»)-l ) '.PRINTXSCHRtO) !GOTO13010

13010 GQTO13020

13900 REMARK—THIS CONVERTS NUMBERS ON DISK TO BECOME REGULAR BASIC DATA STATEME NTS MITH A LIMIT OF 210 CHARACTERS PER LINE 65000 'CONVERT

ABM

PRODUCTS

631 B ST. SAN DIEGO, CA 92101 (714)235-6602

174 May 1981 © BYTE Publicaiioni Inc

Circle 192 on inquiiy card.

The business information you need at the turn of a Icey.

Datadex is a new interactive business management system designed for the Apple personal computer. It's from lUS, the people who brought you EasyWriter^" and who are bringing you new products for office automation, education, and development systems.

Datadex is short for data index. It lets you put all your business data into your Apple the way you like to see it and manipulate it any way you want. It adapts to your way of doing business.

Want to generate a sales report? Just press four keys and fill in the blanks. That puts your sales data into the computer. Now, your report: Datadex designs it for you, based on what you've entered. Nothing to it. That's power!

You can do the same with phone lists, mailing lists, dealer names or inventories.

PUT DATADEX

IN YOUR APPLE.

They all enter Datadex and form your own personal data base.

Want to find a company but don't know how to spell its name? Try something that sounds close, and our Soundex routine will find it. It is very forgiving on typos and extra spaces.

=(. CHECKBOOK )"

PDVEE

flLOISIUS ZUKRZnUSKI

AMOUNT * 923.77 GROSS * 923 771

PRESS 'ESC FOU SVSTEH COMMAND?

Soundex helped us find Mr. Zuknawski when we were balancing our checkbook. We weren 'I sure how to spell Al's name, so searched for Al Z and found him. Instantly. The check register and several other applications are free with Datadex.

Want a specific piece of information, like sales for January 14-21? Inquire Datadex and the answer comes up on the screen right now. And right.

Want a report of all sales in ZIP code areas starting with 9? Sure. Just ask it to print a report.

But seeing is the only way to believe. Get a demonstration of Datadex at your local Apple dealer. See the personal computing power it can bring to your office and home. If you've looked at a VisiCalc-type program, see Datadex before you buy.

By the way, about lUS. We're the Apple of software. We got there by giving you great products and super support. We provide customer service over the phone. Professionally written documentation. And products that are never outdated, only updated. Information Unlimited Software, Incorporated,

281 Arlington Ave.,Berkeley, CA 94707. (415) 525-9452.

Ualadn is a irodemark of-Sonoma Sofiworks. OasyWriier Is > irademark of Cap'n Software. Apple is a iiademark of Apple Computer Inc, ViiiCalc is a trademark of Personal Software, Inc

Let

McGraw-Hiirs Classified Ads Woric For You

Systems Engineer:

40 hours per week at $1,500.00 per month salary. Develop, design, codes, tests and de-bugs microprocessor system, develops software, integrates systems and develops documentation for various customers according to their individual needs.

Requires A B.S. degree in Computer Science or Informational Engineering. Also requires 6 months experience or 1 year Post Graduate Studies in Computer Science or Informational Engineering. Apply at:

Systems & Software, Inc.

2801Finley Road Downers Grove, IL 60515 Attention William Smith

Notice of Omission

Due to a processing error the Lanier Business Products ad which appeared on page 27 of the April Byte had no Reader Service Number.

For more information regarding their "no problem trial offer" circle 475 on the inquiry card in this issue.

Listing 4: Recreation of a graphics picture. This listing shows how the DATA statements generated by listing 3 may be appended to a program that uses them to recreate the original graphics display.

100 QNERRORGOTQlSOtCLS

110 READY.XIFXZiFQRX=XlTOX2:SET(X.Y)tNEXTSGQTO110

120 RESUME130

130 ONERRORGOTOOtCOTD 150

150 REMftRK—THIS SECTION OF PROGRAM FROM LINE lOtfTO LINE 130 IS PROGRAM LISTING NUMBER ZERO THAT WILL RECREATE THE GRAPHIC PICTURE OF LISTING 1. 190 'GOTO300

200 FORI=15360T01i4383:LPRINTPEEK(I) t tNEXTtRETURN

210 REM—LINE ZOO WILL GENERATE HARD COPY QF DATA FOR THE NEXT PROGRAM

300 OF'EN'O".2,-DATAPOKE":FDRI=15360T01&3B3!PRINT*2,PEEK<I):NEXT:CLOSE:STaPtREMAR

« THIS LINE WILL OUTPUT TO DISK

1905 DATA0r5>126>l>5>126>2fS,B>2.123>126>3>5>8r3>123>126>'<l>SrB.'^f 123rl26>SiS>8>S >123>126f&i5r8>6,123f lZ6f7i5iB>7rlZ3>lZ6>8)5>8>8f lZ3>126r9>5f8i9il23>126FlO>S>8> 10.1Z3f 1Z&> 11 >5>8 fill 123>1Z&>1Z>5>8> 12,50.96 •lZilZ3riZ6> 13>S,8> 13 tSOf 51.13 >9S 1910 DATA96,13,123.126.1ti5,8,11,t5,51,11.95,96.11,123.126.15,5.B.15.1'S,t5,15,50 ,51,15 r55> 56, 15 ,61, 62.15 .65 ,66,15,69 I 71, 15.77, 82.15,85,86,15, 89.90,15,95. 96,15.1 23.126.16. 5.8 .16.-^3.')'). 16.50.51.16.55.56.16.61.62.16.65. 66.16.71.72.16.77.78 1915 DATA16f8Si86il6>88>89>16f95>96>16>123>126fl7)5i8>17i')Z>13>17.S0r51>17>S6>57 >17>60.61>17>65>66>17>71>72>17>77>78>17>85>86>17>87.88,17.9S.96.17.123.1Z6.18>S. 8.18.11.12.18.50.51.18.56.57.18.60.61.18.65.66,18,71,72,18.77.79.18.85.87.18 1920 DATA95.96.18.123,126.19. 5. 8.19.10.11.19.50. 51.19. 57. SB. 19. 59. 60.19. 65. 66.19 .71.72.19.77.78.19.85.86.19.87.88.19.95.96.19.123.126.20,5.8.20.39.10.20.50.51.2 0.57.5B,ZO>S9.60r2O.65>66>2Or71>7ZFZO.77.78rZO>8S,86iZ0r88,89fZO>9S>9&>Za>lZ3 1925 DATA126.21,5.8,21.38,39.21.SO.51.21,SB,59.21.65.66.21.71.72.21.77.82,21.85. 86.21.89.90.21,95.96.21.123.126,22.5.8.22.28.51.22.95,96.22.123.126.23,5,8,23,28 ,29,23.10.11 ,23.18,19.23.50 .51 .23.95.96.23, 123.126.21.5,8.21.28.29,21,32,39.21 1930 DATA11.12.21.16.17,21.18.19.21.50.51,21.55.56,21,59.60.21.61,65,21.69.72,21 .83.91.21.95,96.21.123.126.25.5,8,25,28,29.25,31.32.25.38.10,25,12,13,25,18,19.2 5.50.51,25.55,56,25.59.62,25.61.65.25.68.69.25.72.73.25,82.81.25.90 .92 ,25.95 1935 DATA96,25,123,126,26,5,8,26,28,29,26.30.32.26.39.11.26.13.11.26,18.19.26.50 .51.26,55.56.26.59.60.26.61 .63.26.61.65.26.68.69.26,81,83,26,91,93,26,95,96,26.1 23,126,27,5,8,27,28,31,27,33,37.27.10,12,27,11,15,27,18,19,27,50,51,27,55.56 1910 DATA27.59.60.27.62,65,27,68,69,27,80,82,27,85.89,27,92,91,27.95,96,27,123.1 26,28,5,8.28.28.30.28.32.31.28.36.38.28.11.13.28.15.16.28.18.19.28.50,51.28.55,5 6,28,59,60,28,61,65,28.68.69,28,72,73.28.79.81.28.81.86.28.88.90.28.93.96.28 1915 DATA123.126.29.5.8.29.27.29,29.31,33,29,37.39,29.^2,It.29.16,17.29.18.19.29 .50.51.29.55.56.29.59.60.29.61.65.29.69.72.29.71.75.29.78.80.29.83.85.29.89.91.2 9.91.96,29,123,126,30,5,8.30.27,28,30,30,32.30,31,36,30,38,10,30,13,15,30,17 1950 DATA19,30,50.51. 30.77.79, 30,82.81. 30, 86,88, 30,90,92, 30.95, 96, 30, 123,126.31, 5,8,31,30,31,31,33,31,31,36,37,31,39,10,31,11,16,31,50,51,31,76,78,31,82,83,31,8 S.86.31.8B,89,31.91.92,31>95>98,31,123,126,32,5,8,32.30,32.32,31.36.32,38.10 1955 DATA32.15.77.32.82.81.32.86.88.32,90,92,32,95,96,32,123,126.33.5.8,33,31,33 ,33,37,39,33,83,85,33,89,91,33,123,126,31,5,8,31,32,31,31,36,38,31,81,86,31,88,9 0.31.123.126.35,5.8.35.33.37.35.85.89.35.123.126.36.5.8,36,123.126,37,5,8,37 1960 DATA123,126,38,5,8,38,123,126,39,5,8.39,123,126,10,5,8,10,123,126,11,5,8,11 ,lZ3,126,12,S,8,1Z,lZ3fl26,13,5,8>13,123rlZ6>11,St8>11,123,126,15f5.8>15flZ3.126 ,16,5,126,17,5,tZ6 65000 'FOUR

Text continued from page 171:

data file, DATAPOKE, that represents the screen contents in another way. Actually, the contents of the screen are stored in the TRS-80 memory as 1024 contiguous bytes of memory, each byte representing six graphics cells (two cells wide by three cells high). By PEEKing the appropriate memory locations (decimal 15360 to 16383), we can represent the contents of the screen as exactly 1024 numbers, which are written to the DATAPOKE file, as shown in listing 4.

Now, using the DATAPOKE file just generated and the conversion program in listing 3, we come up with a new set of DATA statements. These are merged with another short routine to produce listing 5, which reads data and POKEs the values into video memory.

To get all of these graphics characters on the screen we are now using 1024 different numbers, with an average of 3 to 4 bytes used per number for storage (including commas). In

return for the large amount of memory that is being used, we are only gaining a slight speed advantage over the original program. Let's look for something that will reduce memory usage.

Replacing Blanks with Tabs

Tab characters are stored in TRS-80 Level II BASIC as the value 192 plus the number of spaces to tab to the ri^t. With this knowledge, we can combine a string of spaces into one character of memory by replacing the spaces with a tab character.

Listing 6 uses this information to take a different set of numbers off the screen. The program will generate a new set of numbers that may then be converted to DATA statements using the converison program. To list these same values to a printer, merely remove the END statement from line 660.

Note that in listing 6, the computer was not told to store any of the figures for regular printable charac

176 May 1981 © BYTE Publicatioiu Inc

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178 BYTE May 1981

Listing 5: This program takes the DATA statements generated by listing 4 and POKEs the information directly into the screen memory.

50 0 DEFINTI-NJCLS

520 FDRI=15360TD16383!READft;POKEI.AiNEXT 530 GOTO 530

550 REM—LINES 50 0 TO 520 READ DATA STATEMENTS AND POKE THE VALUES INTO SCREEN MEMORY

1905 DATA32,32.170Fl9lFl59,l')3.113Fl'13.113fl13»H3fl13.113rH3f 113f 113»113,113,1 13.113,113Ft43» 113.l'»3f 113.113. l'»3fl13il'l3Fl'(3»143»113rl13fl^3» 113,113,113,113,1 13.113.143.113,113.113.113.113,113,113.113,113.113.113,113,113»113.113,113,113 1910 DATA113.113,113.175.191.119.32.32.170.191.119.32.32.32.32.32.32.32.32.32.32

, 32 ,32,32,32,32 r 32,32,32,32,32,32,32.32.32,32,32,32.32,32,32,32,32,32,32,32,32,3 2.32,32,32,32,32,32,32,32,32,32,32.32,32,32,32,32,32,32,32,170.191,119,32,32 1915 DATA170,191,119,32,32,32,32,32,32,32,32,32,32,32,32,32,32.32.32,32,32.32,32 .32.32.32.32,32.32.32.32.32.32.32.32.32.32.32.32.32.32,32.32.32.32.32.32.32,32,3 2,32,32,32,32,32,32,32,32.32.170.191.119.32.32.170.191.119.32.32,32,32,32,32 1920 DATA32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32 ,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32.32,1 7 0,191,119,32,32,170,191,119,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32 1925 DATA32, lis0,176,176,191, 131,131,131,131,131,131,131,131, 131, 131,131,131,131, 131,131,131,131,131,131,131,131,171,119,32,32,32,32,32,32,32,32,32,32,32,32,170, 191,119,32,32,170,191,119,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,181 1930 DATA13S,32,32,191,32,138,181,32,186,133,170,119,130,171,1 SI,129,170,151 , 131 ,129, 17(1, 181, 158,129, 32, 170, 119,32, 32, 32, 33, 32, 32 ,32, 32, 32, 32, 32, 32, 17 0,171, 119, 32,32,170,191,119,32,32,32,32,32,32,32,32,32,32,32,32,32,32,160,158,129,32,32 1935 DATA32,191, 32, 32, 171,188, 151,32, 17 0,119, 32, 17 0,119, 32, 170, 151, 32,32,17 0,159 ,180,32,32,170,119,32,32,32,32,32,32,32,32,32,32,32,32,170,191,119,32,32,170,191 ,119,32,32,32,32,32,32,32,32,32,188,110,110,110,110,113,188,110,110,110,188,191 1910 DATA32,32, 32,131,32,32,130,129,32, 130,129,32,130,131,131,129,130,129,130,12 9,32,170,119,32,32,32,32,32,32,32,32,32,32,32,32,170,191,119,32,32,170,191,119,3 2,32,32,32,32,32,32,32,32,191,181,151,131,131,175,182,173,111,131,191,191,32 1915 DATA170,119,170,189,ISO,191,32,190,131,111.32.32.32,160.190,135.131,131.175 .180.170.119.32.32.32.32.32.32.32.32.32.32.32.32.170,191,119.32.32.170.191.119)3 2.32.32.32.32,32.32.32.160.191.167.190.135.175.180.139,189.155.180.191.191.32 1950 DATA170,119,170,119,131,191,32,175,176,156,176,32,181,159,141,190,135,175,1 80,139,191,119,32,32,32,32,32,32,32,32,32,32,32,32,17 0,191,119,32,32,170,191,119 ,32,32,32.32.32,32,32,32,130,129,191,153,183,157,187,119,130,175,182,179,191 1955 DATA176,176,176,176.176.176.176.176.176.176.176.176.190.135.32.191.153.183. 157,187,119,170,157,132,32,32.32,32,32,32,32.32.32,32,32,170,191,119,32,32.170.1 91,119,32,32,32,32,32,32,32,32,32,32,130,175,180,190,135,32,32,32,32,32,32,32 1960 DATA32,32,32,32,32,32,32,32,32,32,32,32,32,32,130,175,180,190,135,32,32,32. 32,32,32,32,32,32,32,32.32,32.32.32.170,191,119,32,32,17 0,191,119,32,32,32,32,32 .32. 32.32.32.32.32.32.32.32.32.32.32.32.32.32.32.32.32.32.32.32.32.32.32.32.32 1965 DATA32.32.32,32,32,32,32.32.32.32.32,32.32.32.32,32,32,32.32.32.32.32.32.32 .32.170.191,119,32,32,170,191,119,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,3 2.32.32.32.32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32,32 1970 DATA32. 32, 32,32,32,32,32,32,32,32, 32,32,32,32,32,170,191,119,32, 32,170,191, 119,32.32.32.32.32.32.32.32.32.32.32.32.32.32.32,32,32.32.32.32.32.32.32.32.32.3 2,32,32,32.32.32.32.32.32.32.32.32,32,32,32,32,32,32,32.32.32.32.32,32.32.32 1975 DATA32,32,32,32,32,170,191,119,32,32,170,191,189,188,IBS,188,188,188,188,18 8,108,188,188,188,188,108,188,188,188,188,188,188,188,188,188,188,188,188,188,18 8,188,188,188,188,188,188,188,188,188,188,188.188.188.188.188.188.188.188.188 1980 DATAiaS.188.188.188.ISB.188.188.188.188.188.190.191.119 65000 'FIVE

Listing 6: A routine that compresses a string of spaces into a TAB character that represents the number of spaces in the string.

600 OPEN■0■.2.■PRINTCHR":L=l;A=PEEK(15360):P0KE16383.32:IFA<129THENA=32

610 FQRI=15361T016383:B=PEEK(I);IFE<129THENB=32

620 IFB=AANDA=32THENL=L+1:GOT066 0

630 ifb=32THEnl=i:c=a:gosub690:a=b:gotq660

610 IFA=32THENC=192+L!GOSUB690;GOT0655 650 C=A:GOSUB690 655 A=B

660 nextiiend

690 print*2,c:return

695 remark lines 600-690 output to disk, lines 900-960 output to lineprinter 900 p0ke16383.32sl=l:a=peek<15360 >:ifa<129thena=32

910 F0RI=15361T016383;B=PEEK<I)!IFB<129THENB=32

920 IFB=AANDA=32THENL=L+1;GOT0960

930 IFE=32THENL=1 :LPRINTA; :A=E!GOT0960

910 IFA=32THENLPRINT192+L!:G0T0955

950 lprinta;

955 A=B

960 NEXTIiEND

&50D0 'SIX

Listing 7: Program to display data stored in the compressed format.

800 DEFINTI-N:DNERRORGOT0830}CLS

820 readj:printchr*(J)!:goto820

B30 RESUME810

BIO POKE 16383,119

850 GOTO 850

Listing 7 continued on page 180

ters (such as blanks, letters, or numbers) because these can be more efficiently printed using PRINT statements. If you have both graphics and alphanumeric characters on the screen, the programs shown here will treat alphanumerics as a series of blanks for DATA purposes.

The next routine, listing 7, displays the data from the DATA statements created using listing 3 and the data file from listing 6, PRINTCHR. This routine requires graphics characters on every line. If you go more than sixty-three successive blank spaces, you will get a function error, so we are assuming that graphics will be present on every line.

In the sample data in listing 7, the last item in the DATA statements would give us a function error, so we did not use it in this particular example. Instead, a 149 was POKEd into the space (16383).

One problem that must be solved concerns the method of ending the loop that contains the DATA statements. For example, the three BASIC statements in line 820 of listing 7 are an endless loop that reads an item from the DATA statement and prints it. If we plan to use the same routine for different sets of DATA statements, we need to get the program out of the loop after it has read the last item of data; if we do not, the program will end immediately with an out-of-data error.

There are several ways this problem can be approached. Although tedious, we could count the number of items in the data statements and put the READ statement in a do-loop. We could also append a certain flag value (one that would not otherwise be in a valid list of data) to the end of the data statements and put the READ statement in a loop that stops when it reads the flag value. Instead, we decided to use the ON ERROR GOTO option that is available in Level II BASIC.

In listing 7, the ON ERROR GOTO 830 (in line 800) is executed when the READ tries to read past the last data value. (Without this statement, the program would end.) The RESUME 840 statement at line 830 causes the program to continue, even after what would otherwise be a fatal error. The loop to itself at line 850 allows us to fill the entire video screen with the picture being displayed, without ending the program and scrolling the

May 1981 © BYTE Publications Inc 179

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Listing 7 continued

1905 DATA191fl70 ,113f1^3.113r113 .113.113fl13f113

1910 DATA113rl13 ,218.170,191,119 ,191,131,131,131 1915 DATA131,131 ,193,139,181,193 ,193,170,119,201 1920 DATAiaB,151 ,201,170,191,119 ,191,195,131,191 1925 DATA170,119 ,173,111,131,191 ,J3;U131>175,180 1930 DATA13S,17:j ,176,1S6,176,193 ,191,119,200,130 1935 DATA176,176 ,170,1S7,132,203 ,180,190,135,207 1910 DATA218,170 ,188,180,188,188 ,188,188,183,188 1915 DATA188,188 650 0 0 'SEUEN

191, >113r 113»

113, 191, 131, 131, 186, 170, 193, 191, 130, 201, 191, 170, 180 , 1B1, 129, 176, 170, 170, 191, 188, 188, >18S>

159,113, 113.113, 113,113,

175,191, 170,191, 131,131, 171,119r 133,170, 191,119, 170,119, 170,191, 129,193, 170,191, 193,170, 117,201, 139,189, 159,161 , 191,153, 176,176, 191,119, 191,119, 119,191, 188,188, 188,188,

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189

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Listing 8: Routine to convert the graphics data to strings of characters.

110 0 P0KE163B3,32: OPEN ■ Q ■, 2," PRINTSTR ■!L=l: A=PEEK(15360 > JIFfl<129THENft=32 1110 F0RI=15361T0163a3:e=PEEK<I> iIFB<lZ9THENBe32 1120 IFB=ATHENL=L+1:GOTQ1160 1130 PRINT*2,L",'AiL=i;A=E

1160 nexti:end

1170 remark—print out to disk

650 0 0 'EIGHT

top two lines off the top of the screen.

Graphics Using STRINGS From an examination of the DATA

statements in listing 7 it is apparent that we still have a lot of repetition. This is especially true when we print a straight line or a solid area of graphics. In order to save even further on DATA items and to speed program execution, the DATA may be rearranged to allow the printing of strings of identical characters (in much the same way that we printed a line of "set" graphics points in listing 2).

The STRING$(X,Y) command in Level II BASIC allows us to print X identical characters, each of which has an ASCII value of Y. When reading the video screen with PEEK statements, we will be looking for identical adjacent values. The data we print to a disk file (and later translate to DATA statements) will be a pair of numbers, the first number being the repetition factor and the second being the ASCII value of the character to be repeated. This method has been used to create the data file PRINTSTR in listing 8, and it displays graphics faster than previous methods.

Please note that in each of these programs that use PRINT for output purposes, the very last character on

the screen (position 16,383) will not print, so if any SET, RESET, or POKE had been done into this area in the original program, it would be left blank. Your program could remedy this by POKEing 16383 with the proper value.

Listing 9 restores the graphics image to the video screen by reading the data items in the DATA statements (again created by the PRINTSTR file and listing 3). This program reads pairs of data items and prints them using STRINGS in line 1420 to expand the pair of nimibers to a string of proper length.

Listing 9 demonstrates that it is possible to extend the number of lines on which graphics are not required. However, they must still be present on at least every fourth line, because the length of each string must be less than or equal to 255, a limitation of Level II BASIC.

Combining Methods

Listing 10 (to create the data file FASTER) and listing 11 (to print the image from the DATA statements) refine the above method by storing a single data item instead of a data pair, when the character being repeated is a space (decimal value 32). Since the

Text continued on page 184

180 May 1981 © BYTE PubUcatlons Inc

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Listing 9: Routine to display graphics data converted to strings of characters.

1390 CLEAR 3000

110 0 DEFINTI-N;QNERRORGOTQ11301CLS

1120 READIfj:pRINTSTRING»(IiJ>;iGOT01120

1130 RESUME111D 1110 POKE 16383.119 1150 GOTO 1150

1905 DATA2r32rl,170,1.191.1,159,56,113fI,175,lfl91fl.l19>2,32,l,170.1fl91.1f119f

56 .32 f 1.170 rlr 191 f 1.119, 2, 32.li 170. Irl91,l. 119, 56,32.1,17 0.1,191,1,119 r2f 32,1,17 0,1,191,1,119.56,32,1,170,1,191,1,119,2,32.1,170,1,191,1,119,17,32,1,160,2,176 1910 DATAl,191.21.131.1.171.1.119.12.32,1.170.1.191,1.119.2,32,1,170.1,191.1.119 > 16.32.1 > 181.11135.2.32.1 r 191F1.32. li 138.1 >181>l>32>l>186f 1.133.1.170.1> 119.1,13 0.1.171.1.151.1.129,1.170.1.151.1.131.1.129.1.170.1.181.1.158.1.129.1.32.1.170 1915 DATAl.119.12.32.1.170.1,191,1.119.2.32.1.170.1.191.1,119.11.32.1,160.1.158. 1,129,3.32.1.191,2,32,1,171,1.139,1,151,1,32,1,170,1,119.1,32,1,170,1,119,1,32,1 ,170,1.151.2.32.1.170.1.159.1.180.2.32.1.170.1.119.12.32.1.170.1.191,1,119,2 1920 DATA32.1.170.1.191. 1.119.9.32.1.188,1.110. 1.113.1.188.3. 110.1.188.1.191.3.3 2.1.131.2.32.1.130.1.129.1.32.1.130.1.129.1.32.1.130.2.131.1.129.1,130.1.129.1.1 30,1,129,1,32,1,170,1,119,12,32,1,170,1,191,1,119,2,32,1,170,1,191,1,119,9,32 1925 DATAl, 191, 1,131,1, 151,2,131, 1,175, 1,182, 1,173, 1,111, 1,131, 2, 191, 1,32, 1,170, 1,119,1,170,1,189,1,180,1,191,1,32,1,190,1,131,1,111,3,32,1,160,1,190,1,135,2,13 1,1,175,1,180,1,17 0,1,119.12,32,1,17 0,1,191,1,119,2,32,1,170,1.191,1,119.0,32 1930 DATAl, 160, 1,191,1,167, 1 ,190, 1,135, 1,175, 1,180,1,139, 1,189, 1,155.1,130.2.191 ,1,32,1,170,1,119,1.170,1,119.1,131,1,191,1,32,1,175,1,176,1,156,1,176,1,32,1,13 1.1. 159. 1.161. 1.190.1.135. 1.175.1,180.1.139,1,191,1,119,1;;, 3,;, 1,17 0,1,191,1,1'19 1935 DATA2, 32. 1,170,1,191,1.119, 8. 32. 1,130,1,129,1,191,1, 153, 1,183, 1,157, 1,187,1 .119,1,130,1,175,1,132,1,179,1,191,12,176,1,190,1,135,1,32,1,191,1,153,1,133,1,1 57,1,187,1,119,1,170,1,157,1,132,11,32,1,170,1,191,1,119,2,32,1,170,1,191,1,119 1910 DATAl0.32.1.130.1,175,1.180.1.190.1,135.21.32.1.130.1.175,1,180,1,190,1,135 ,15.32,1.170.1.191.1.119.2.32.1.170.1.191.1.119.56.32.1.170.1,191,1,119,2,32,1,1 70,1.191.1.119.56.32.1,170.1.191.1.119.2.32.1.170.1.191.1.119.56.32.1.170.1.191 1915 DATAl,119,2,32,1,170,1,191.1,189,56,188,1.190,1.191 65000 'NINE

Listing 10: Routine to generate a more compact graphics data file.

1500 P0KE16383.32:L=1!A=PEEK<15360);IFA<129THENA=32 1505 QPEN'O',2,'FASTER'

1510 FQRI=15361T016383:B=PEEK(I);1FB<129THENB=32

1520 IFB=ATHENL=L+liGQTO1560

1530 IFA=32THENLPRINT192+L fELSELPRINTL tA}

1535 IFA=32THENPRINT»2.192+LELSEPRINT*2 , L ■ . ■ A

1510 L=liA=B

1560 nexti:end

1570 remark—program listing number ten to print out listing for next program an d send it to disk

1580 REMARK—IF HARD COPY IS NOT DESIRED, ELIMINATE LINE 1S30 65000 -TEN

Listing 11: Routine to display data as created by listing 10.

1690 CLEAR 3000

17 0 0 DEFINTI-N:DNERRDRGOT01730:CLS

1720 READI : IFK192THENREADJ: PRINTSTRING$ (I. J) i ELSEPRINTCHR*(I> ! 1725 GOT01720 1730 RESUME1710 1710 POKE 16333.119 1715 GOTO 171S

1750 REMARK—PROGRAM NUMBER ELEVEN LINES 1600-1710

1905 DATA191,1,170,1,191,1.159.56.113,1,175,1,191,1,119,191,1,170,1,191.1,119,21 B. 1.170.1.191,1,119,191,1,170,1.191.1.119.218.1.170.1.191.1.119.191.1.170.1.191.

1.119.218,1,170,1,191.1.119,191,1,170,1,191,1,119,209,1,160,2,176,1,191,21,131 1910 DATAl, 171,1, 119,201,1,170, 1,191, 1,119,191,1,170,1,191,1,119,208,1,181,1,135 .191,1,191,193,1,138,1,181.193.1.186.1.133.1.170.1.119.1.130.1.171.1.151.1,129.1 ,17 0,1,151,1,131,1,129.1.170,1,181.1.158,1,129.193,1,170,1,119,201,1.170.1.191 1915 DATAl.119,191.1,170,1,191.1.119.206.1.160.1.158.1.129,195.1.191.191.1.171.1 ,188,1,151,193,1,17 0,1,119,193,1,170,1,119,193,1,170,1,151,191,1,170,1,159,1,180 ,191.1,170,1,119,201,1,17 0,1,191,1,119,191,1,17 0,1,191,1,119,201,1,188,1,110 1920 DATAl,113,1,188,3,110,1,188,1,191,195 ,193,1,130,2,131,1,129,1,130,1,129,1,130,1

1,131,191,1,130,1,129.193.1.130.1.129 129,193,1.170,1,-119,201,1.170.1.191.1

182 May 1981 © BYTE PublicaUons Inc

,119,191,1,17 0,1, 191,1,119,2 01,1,191,1,181,1,151,2,131.1,175.1.182.1.173.1.111

1925 DATAl. 131.2.191.193.1.170.1.119.1,170,1,189,1,180.1.191.193.1,190,1.131,1.1

11.195,1,160,1,190,1,135,2,131,1.175.1.180,1,170.1,119,201.1,170,1,191,1,119,191

.1.170.1.191.1.119.200.1.160.1.191,1.167.1,190,1,135.1.175.1,180,1.139,1,189

1930 DATAl,155,1,180,2,191,193,1,170,1,119,1,170,1,119,1.131.1,191,193,1,175.1,1

76,1,156,1.176,193,1,181,1,159,1.161,1,190,1,135,1,175,1.180,1,139,1,191,1,119.2

01.1.170.1.191.1.119.191.1.170.1.191.1.119.20 0.1.130.1.129.1.191.1.153.1.183

1935 DATAl. 157.1,187.1,119,1,130,1,175,1,182,1,179,1,191,12,176,1,190,1,135,193,

1.191.1.153.1.183.1.157.1.187.1,119.1.170.1.157.1.132.203.1.170.1.191.1.119.191.

1.170.1.191,1,119,202,1,130,1,175,1,180,1.190.1,135,213,1,130,1,175,1,180,1,190

1910 DATAl, 135, 20 7, 1 , 17 0, 1, 191 , 1 , 119, 191,1 ,170 ,1, 191, 1 ,119, 213,1, 170 , 1, 191 , 1 ,119

,191,1,170,1,191,1,119,218,1,170,1.191.1.119.191.1,170.1,191.1.119.218,1.170.1.1

91,1.119,191,1,170.1.191,1.189.56.188,1,190,1.191

65000 -ELEVEN

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Listing 12: Routme that converts screen data to the most compact, fastest form discussed in this article.

IBOO POKE16383tl19:L»lJA=PEEK<15360)JIFA<i29THENA=32 ia05 QfEN-O',2, "FASTEST"

1810 F0RI==1S361T016383:B=PEEK(I> iXFB<129THENB°3Z 1820 IFB^ATHENLxL+liGOTOlBAO

1830 IF A=32 THEN PRINT*2il9Z+LtEL8E IF L'l PRINT«2tAELSEPRINT*2>L'>'A

1810 l=i;a=b iBAo nexti:end

650 0 0 'TMELUE

Listing 13: Routine to display the compressed data generated by listing 12.

1905 DATA191f170il91rl59»56» 170rl91il19>ZtS.170f191f119> 160.2t176.191t21t131F171.119 1910 DATA191,193,13a.l81.193 .181,158.129.193,170.119.201 .191.171.188,151,193,170,119 1915 DATA119,201.170,191,119 ,195,131.191,130,129,193,130 01,170,191,119,191,170,191,1 1920 DATA193,170,119,170,189 80,170.119.201.170,191,119,1 89,155,180,2,191.193.170.119 1925 DATA161.190.135.175.1B0 ,129,191,153,183.157.187,119 157.187.119,170.157,132.203, 1930 DATA213.130.175.180.190 .191.170.191.119.218.170.191 .56.188.190.191 2000 DEFINTI-N!ONERRORGQTQ20 2020 READI:IFI<129THENREA0J: 2025 GOTOZ020 2030 RESUME2010 2010 POKE 16383,119 2015 GOTO 2015 2050 REMARK—PRQGRAH NUMBER 65000 'THIRTEEN

Text continued from page 180:

113.175,191,119,191.170.191. 191.170,191.119.218,170,191. .201.170,191,119,191.170.191 ,186,133,170,119,130.171.151 .170.191.119,191,170.191.119 .193.17 0.119.193,170,151,191 191,170,191,119,201,188.1.1 ,129,193.130.2.131.129.130.1 19.201,191.181.151.2,131,175 .180,191.193.190.131.111.195 91,170,191,119,20 0.160.191.1 .170.119.131.191.193.175.176 .139.191.119.201.170.191.119 .130.175,182.179.191.12,176. 170.191.119.194.170.191.119, .135.207.170.191.149.194.170 119.191,170.191.149.248.170

119,218,170,191,119,191. 119,191.170.191.119,209, ,119,208,181,135.191 ,129,170,151,131.129.1/0 .206,160.158.129.195.191

170.159.180.191.170 10.113.188.3.110.188.191 29.130.129.193.170,119,2 .182.173.111,131.2.191 ,160,190,135,2,131.175.1 67.190.135.175.180.139.1 .156.176.193.181.159 .191.170.191.119.20 0.130 190.135.193,191.153.183. 202,130,175.180.190.135 .191.149.248.170 >191>149 .191.149.194.170.191»189

30:CLS

PRINTSTRING*<I.J>(EL8EPRINTCHR*<I);

THIRTEEN TO EXECUTE PRINTOUT LINES 1900-2040

tab characters have a decimal value of 193 or greater, listing 11 can distinguish between tab values (to be printed using CHR$) and number pairs (to be printed using STRINGS). This gives us a slight improvement in speed over the previous method.

A variation of this program comes to mind, since the number 1 is really not needed when using the STRINGS function. If the length of the string is 1, we can PRINT CHR$(176), instead of using STRING$(1,176) as we would when using a number pair (see line 1910 of listing 11). That being the case, it is possible to rewrite the routine and, by adding one statement, tell the computer to go ahead and print out only 1 character.

Features of several of these programs may be combined. The space saver, which prints a series of spaces as the value 192 plus the number of spaces (as done in listings 6 and 7), may be combined with printing of a string of graphic characters using STRINGS (see listings 8 and 9). By combining these with the length-1 technique discussed above, we have a slightly more complicated program.

It does, however, run a bit faster than its predecessor and uses much less memory in the DATA statements.

The final (and fastest) version of this program is given in listings 12 and 13. Using the three techniques just discussed, listing 12 writes data values out to the data file FASTEST. When this data is converted to DATA statements (by running listing 3), the program in listing 13 (which includes the data statements) uses them to recreate the original picture on the video screen.

Conclusions

These programs serve to illustrate alternative methods of using graphics on the TRS-80 Model I with Level II

BASIC. These are not the only techniques that can be used, but are merely our suggestions for ideas you can try in some of your programs.

In some cases you will be sacrificing memory space for printout speed. The decision as to which of these methods is best for your particular program rests solely with you. The easiest way to find out is to put the various routines into programs and experiment with them.B

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BYTE May 1981 185

Education Forum

Getting Problem-Solving Advice from a Computer

James W Garson Department of Information Engineering University of Illinois at Chicago Circle Box 4348

Chicago n 60680

Over the last three years, Paul Mellema and I have been at work on EMIL, an interactive computer program that we use to help teach our courses in formal logic.

Since June 1979, we have been devoting our efforts to implementing a computerized "copilot" for EMIL that students can call on to solve problems.

The methods used to give our students advice are easily implemented and effective. The approach does not easily fit into the standard categories of educational computing (ie: record keeping, drill and practice, testing, games, simulation, etc). It is an approach that has potential for widespread application. The goal of this program is to help students develop and use skills and strategies needed to creatively solve problems that do not necessarily have only one solution. The program is Socratic in its style, because it asks students leading questions that help them analyze and resolve their difficulties.

In the study of formal logic, students are required to construct formal proofs. A proof is a series of statements leading to a conclusion. Each step of the proof is assumed to be true or derived from previous steps according to the rules of logic. The proof is intended to demonstrate that the conclusion follows logically from the assumptions.

Learning this type of thinking is valuable to students not only because it can lead to a mastery of logic, but because it also gives students experience in the kind of creative problem solving characteristic of mathematics, theoretical science, and many other disciplines and reallife pursuits.

Giving students practice in the creative solution of formal problems is important in education and particularly

About the Author

James Carson is a member of the Department of Information Engineering, University of Illinois at Chicago Circle. This article is a revised version of a paper he delivered to the National Educational Computer Conference, June 1980, in Norfolk VA. The work described was carried out under the National Science Foundation Grant Number SER79-00527. This article does not represent the views of that foundation. Another article by Mr Garson, "The Case Against Multiple Choice," can he found in The Computing Teacher, February-March 1980, page 29.

186 Mqr 1981© BYTE PubBcalfcnuIhc

so in the sciences. Scientific knowledge is too often presented as if it descended from heaven or was created by some form of superhuman intelligence. Very little effort is given to help students appreciate the thinking processes that go into the analysis and solution of scientific problems. There is a tendency to obscure the very human process of trial and error, of trying out strategies, of assessing failures, and of creating better lines of attack, which are all part of scientists' daily life. A course in logic gives students the opportunity to refine their problemsolving skills in an environment where the difficulty of the problems can easily be adjusted to their growing abilities.

In a traditional course in logic, where students' abilities vary widely, those who do not have an initial knack for problem solving are at a serious disadvantage. Even when strategies for proof building are carefully discussed in class, some students invariably complain that they cannot solve a new problem on their own in spite of understanding the lectures. Part of this difficulty is that some students carmot convert verbal explanations of techniques into strategies for dealing with new situations. Their problem is somewhat similar to that of a student driver who has mastered a lecture on how to operate a car, but carmot convert this knowledge into the appropriate series of actions for handling a real car on a real road. Driver training classes overcome this problem by using the guidance of a copilot who helps correct errors while the students practice the task.

Similar sorts of tutoring are very effective for helping students who cannot apply the verbal knowledge about logic to the construction of proofs. If students are asked to "think out loud" while attempting a proof, a gentle nudge here and there often leads to success. If they do not understand the rules or simply have not bothered to learn them, guiding them through a few proofs tends to straighten things out quickly, and it improves confidence and motivation. Just as in teaching most skills, effective methods involve letting students perform given tasks under guidance. Lecturing on the proper procedures and telling students to "go home and do likewise" is relatively ineffective.

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Of course there are good reasons why tutoring is not widely used in introductory logic courses. These classes are usually quite large, so tutoring simply takes too much of the teacher's time. Besides that, grading formal proofs constructed by students is tedious, so teachers tend to give students relatively few exercises that require them to create such proofs. Even students who do well in logic generally do not get enough practice to develop very much skill. Often the teacher relies on exercises that require a single answer — exercises that ask students to give justifications for the steps of a completed proof. This does familiarize students with the rules, but it gives them no practice in the art of building up a proof.

Enter the Computer

Computers make it possible to simulate the tutoring situation. Students can enter their proofs at the terminal, and the computer can determine whether each line follows from previous lines and describe the difficulty if one does not. If students get lost, the computer can give advice on how to proceed.

In 1976 we wrote a program called EMIL that lets students enter their proofs at the terminal and monitors their progress. The program has been used in a variety of courses at Notre Dame and has recently been adopted at Rutgers University. EMIL has several advantages over other proof-checking programs. First, there are a large number of logic textbooks, each with its own version of the rules of logic. Our program is the only one that lets a teacher supply the program with the set of rules used in his or her class, instead of forcing the use of the text with the set of rules written into the program. Second, the EMIL program is extremely gentle with students' input and generally repairs typing mistakes rather than complaining about them. This is important because many students are unfamiliar both with the terminal keyboard and the notation of logic. Third, the program lets students enter statements at the bottom (ie: end) of the proof so they can work the proof backwards if they desire to do so.

We allow and, in fact, encourage this because effective proof-building requires an analysis not only of the statements already derived, but of the statement to be proved as well. Often the proof can be considerably simplified by using the goal statement as a guide for determining the steps previous to it. Our program allows students to employ such strategies right at the terminal, instead of submitting a finished product to the computer for checking. The fourth advantage of our program is the main topic of this article: since September of 1979 EMIL has been giving students good advice on how to solve problems they find difficult. In this way, it is providing a good portion of what can be offered by a human logic tutor.

Programming Strategies

There are several distinct approaches to designing a computer program that can offer advice on formal proof construction. The first is simply to store a completed version of each proof and a list of comments that are intended to help students who ask for aid in deriving a given line. If the comments prove unhelpful, students can ask to see the next line of the stored proof or, indeed, any number of lines up to and including the entire proof.

This hint approach requires that a completed proof

May 1981 © BYTE Publicationii Inc 189

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must be stored in the computer with appropriate comments for every problem students will work on. It also presupposes that there is only one reasonable sequence of steps that leads to the conclusion. If students approach a problem in an unusual way, there may not be enough similarity between their proofs and the stored proof for the computer to be of any help. Finally, it presupposes a top-to-bottom pattern of proof construction. But very often, from a given step in a proof, it is not at all apparent how to get to the conclusion. Such strategies must be explained with reference to what happens later in the proof. This sort of hint routine fails to help students appreciate global strategies that require knowledge not just of where the proof has been, but of where it is going. These are generally the most useful strategies.

Another technique is to write a program that allows the computer to generate a solution to students' problems and to recognize certain standard situations during the course of that solution. This strategy eliminates the need for storing a proof with commentary for each problem, since the computer generates its own solutions. But this strategy runs the risk of generating strange proofs that students are unlikely to recapitulate. Also, each formulation of the rules of logic would require its own customtailored program for generating proofs. Furthermore, the program to generate comments must be very carefully written to avoid misleading advice. Most importantly, this approach still does not help students to see global strategies; like the stored proof approach, it uses a top-tobottom pattern of proof construction. So, this approach also confines itself to giving advice only about the next line of the proof.

Another difficulty with both of these approaches to the design for an advice giver is that the program does not attempt to construct advice on the basis of whatever progress the student may have already made on the proof. This tends to discourage invention of novel, yet promising, partial solutions. It can devalue students' creative abilities and lower their self-confidence. It dampens students' engagement in the problem-solving process while reinforcing stereotyped solutions.

Our Approach

The third approach to the design of an advice giver, the one we have adopted, overcomes these problems by paying more attention to the techniques actually used by human logic tutors. One of the main things a human tutor should do is to provide students with effective problem-solving tools for analyzing situations and for breaking problems into simpler subproblems. The same tools can then be applied to these simpler problems. An effective tutor does not give a solution or even pieces of it. Instead, the tutor provides an apprenticeship in the art of asking relevant questions, whose answers lead students to see how problems can be broken down into more manageable parts. Questions like "Can you apply this rule to statements you have already derived?" and "What rule could be used to derive a statement of this type?", when presented in a coherent sequence, are very effective for helping students develop strategies to be used effectively in a wide variety of proof-building problems.

The central function of our advice-giving program is simply to ask students leading questions and then branch

Circle 23 on Inquiry card.

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Table 1: Sample records from the question file of our program that is designed to give advice to students concerning the construction of formal proofs in logic courses.

192 May 1981 © BYTE Publications Inc Circle 349 On inquiry Card.

to new questions on the basis of the answers. Eventually, the program runs out of questions to ask, and specific advice is given on the basis of the information provided in the previous answers. (The questions can be thought of as being structured in a tree, with the path taken along the branches being determined by the students' answers and the advice for each situation being located at the tip of each branch.)

Programming the question-asking routines for our own advice giver was quite simple. Thus the main focus of our attention has been the creation of a file of questions with real pedagogical merit. Since the questions are not written into the structure of our program, modifying the question tree in response to what we learn about effective advice is a painless process that does not require any programming expertise.

Our question file has a very simple format. (See table 1.) Each record contains the text of a question followed by a list of acceptable answers. Each answer is followed by a number indicating which record to jump to in case the student responds with that answer. The last item in each record begins with a "*" (which indicates that there are no more acceptable answers) and contains text that is printed in case the student does not respond with one of the acceptable answers. Most of the questions we ask are answered with yes or no, but we found the use of other sorts of answers more convenient for certain questions. The text of the advice to be given is simply stored in the question file followed by "*". This indicates that this pseudoquestion has no acceptable answers, and the program should stop after printing the advice.

Expansion

We have built a number of improvements into this simple program. The first has to do with the fact that the sequence of the questions should vary depending on how much students have learned and how difficult their problems are. Our solution to this problem is to assign each problem a level number and to use this number to route the program to separate question trees for each level we have defined.

The second enhancement is motivated by the fact that we want to mention items in our questions that change during the execution of the program (for example, the last line number finished in the proof or the name of the rule to be used). Obviously the text of the questions in the file cannot mention specific line numbers or rule names. Our solution is to introduce variables that are replaced with the corresponding specific information just before the question is printed. We have adopted a convention that words beginning with "&" are variables, so a line of advice on our question file might read:

Circle 273 on inquiry card.

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You'll find that Morrow Designs' hard disk systems offer the best price/ performance ratios available for S-100, Cromemco and North Star computers. See the M26 and M10 hard disk subsystems at your computer dealer Or, write Morrow Designs. Need information fast? Call us at (415) 524-2101.

Look to Morrow for answers.

*CP/M is a trademark of Digital Research! Corp. *Cromemco is a trademarl< of Cromemco. Inc. •Norlfi Star Is a trademark of Northi Star Computers. Inc.

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dataKEYper features:

Useful to new users and experienced professionals

Great for software developers

Easy-to-lecrn and easy-to-use

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dataKEYper functions:

CREATE — Information files interactively

EDIT — easy to vary record size and contents

SEARCH — unique data retrieval and statistical

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SORT — very flexible and efficient

REPORT — very versatile report generator

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Note: ESP dataKEYper is prerequisite software.

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'TOU SHOULD APPLY &RULE TO LINE &GNUM"

This directs the program to fill in the specific information about the rule name and line number, for example:

"YOU SHOULD APPLY MP TO LINE 5"

Although our advice-giving program was running with these two enhancements in September, we were still working on a central portion of the program the following January. We still had to program the most important improvement: the development of subroutines that can answer all the questions posed to students by the program and that can comment on any errors in students' responses. Though students are usually accurate in their responses, they occasionally make mistakes that can result in their receiving bad advice. But this is not the only reason for giving the computer the ability to monitor the correctness of students' responses.

Once students run the advice giver a number of times, they become bored with answering a number of seemingly pointless questions. The questions become pointless not because they are not needed in analyzing proofconstruction problems in general, but because a particular portion of the analysis is not needed for the problem being dealt with. When the computer is capable of answering the questions itself, we can decide which questions at particular levels of difficulty should be printed at the terminal, and those the computer should answer for itself by examining the proof being worked on.

Experienced students may resent being asked any questions at all and may prefer the advice giver to merely print specific pieces of advice. However, we believe that for most students who need the advice giver in the first place, posing relevant questions is much more valuable to learning problem-solving skills than is obtaining advice.

Does It Work?

We now have a version of EMIL that answers all the questions it poses. We also have a method for indicating which questions are to be asked under the particular circumstances. There is a need to do more research on how obtrusive the advice giver ought to be in relation to students' progress and cognitive style. However, one of the advantages of our program is that we can easily control the circumstances under which questions are asked. In fact, our program allows the students to suppress the asking of questions if this bothers them.

There is a final reason for programming the computer so that it can answer all the questions: when this is done the program can traverse the question tree on its own and come up with relevant advice. Once advice is available, the program can follow it to construct proofs on its own. Judging from extensive tests of the program, our advice tree turns out to be highly, though not totally, effective for solving logic problems. It is capable of solving over 95% of the problems that we give to our students. This provides us with an important tool for improving our program. By running a large number of problems through our advice giver, we can determine the circumstances under which it is unable to do a proof. Then we use that information to create a more sophisticated version of our question file.

This approach to giving computerized advice has a

194 May 1981 © BYTE Publications Inc

Circle 451 on inquiry card.

Circle 343 on Inquiry card.

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4 valuable references

1981 SOFTWARE WRITERS MARKET:

Where to sell your programs: CDC, Apple, Atari, Digital Equipment, Computervision, Arthur D. Little, MCAUTO, DataTrain, Osborne/McGraw Hill, Computerland...These firms will market and distribute your programs for you or buy rights. Many will provide cash support for program development. Detailed writeups describe what kinds of software they want, payment rates, contract details, who to contact including names, addresses and phone numbers. Hundreds of firms listed, latest revision April, 1981 - $45 (see free offer below)

FREE-LANCE SOFTWARE MARKETING,

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wide range of applications. It can be used, for example, to help college students with their physics homework, to determine the identity of unknowns in qualitative chemistry, to help medical students learn diagnosis, and even to help people determine what is wrong with their cars or whether they should itemize their deductions. All it takes is a simple program to run the questions and a question file that is carefully constructed to reflect the best strategies that people actually use to solve the kind of problems at issue. Depending on the context of its use, some or all of the enhancements to the basic program we have developed could be used.

It is worth pointing out exactly how our advice-giving program differs from the traditional way in which the multiple-choice format is used in CAI (computer-aided instruction). These differences are not particularly striking from the programmer's point of view. In both cases, programs are designed to ask questions and to select new questions on the basis of the answers. The advice-giving program requires a more elaborate branching structure and may differ in being unable to evaluate responses. But the important differences are the ones that are obvious to the educator: these have to do with the educational goals of the program.

The standard objective for using multiple-choice techniques is to help students learn certain facts. In the case of the advice-giving program, the answers are not part of what is being taught. It is the sequence of questions representing an effective problem-solving strategy that we would like students to master. By repeatedly exposing students to questions that have been proven effective in problem analysis, they learn to develop efficient strategies that can be used over a wide range of problems. The whole process of adopting principles of problem analysis is a valuable exercise of problem-solving skills that can be applied to any domain where creative thinking is required.

We should stress that despite our emphasis on strategy learning as an objective to advice-giving programs, the programs are also effective in giving factual information. From our advice giver, our students learn about the rules of logic, their names, their operation, and their functions in proofs. Also important is that our program helps expose students to this information at the exact times when it is most useful: this is the context when they are most likely to be receptive to learning these facts.

Although the advice-giving program may not look very different from standard multiple-choice "courseware" to the programmer, it has radically different educational goals — the most important of which is the development of problem-solving abilities. Given the simplicity of the programming effort as compared to games and simulations, the advice-giving program is particularly attractive for educators interested in developing students' creativity. ■

Education Forum is an occasional feature in BYTE intended to foster debate about the uses of personal computers in the schools and colleges. We encourage reader participation. Contributors should supply their full names and addresses for publication, along with their telephone numbers, which will not be published.

196 May 1981 © BYTE Publications Inc

Circle 212 on inquiry card.

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Desk-Top Wonders

A Chessboard Journey on the TI-59 Programmable Calculator

Michael Gilpin Michigan Technological University Houghton MI 49931

KTTOUR-59 (see listing 1) is a program for the Texas Instruments TI-59 that finds Knight tours on an 8 by 8 board. (A Knight tour is a journey on a chessboard where the Knight lands on each square exactly once.)

To begin, partition the calculator memory locations into 320 program lines and 90 addressable memory locations by pressing 9, *Op, 17. Then enter the program and press B. This initializes values in registers 00 thru 89 as shown in figure 1. The actual chessboard is represented by registers 11 thru 18, 21 thru 28, . . . 81 thru 88. After setting up this initial configuration, the program returns with the display value 0. Enter the initial square number and press C. The program will then move the Knight at

the approximate rate of one move every 33 seconds according to the Rule of Wamsdorf. That is, it will always move the Knight to a square having, at that point in the tour, a minimal number of entrances.

Execution stops with the display value 0 as soon as no additional moves can be found. Pressing D causes the program to flash each move in the format "square.move" (eg: "13.07" means the seventh move was made on square number 13). This allows the user to write down the complete tour on graph paper. If used in conjunction with the Texas Instruments PC-IOOA printer, a hard copy of the tour is produced using the same format. Then for a dif

Text continued on page 202

Listing 1: KTTOUR-59, written for the Texas Instruments TI-59. Loc. Keys

000 003 006 010 017 020 023 027 034 037

^ 8 ^ ^STO^ (^09 ^

(^SUM^ 10 ^

8J (^STO^ 00 ^

Comments

Start with 9 exits. Prepare to test 8 jumps.

Put KT on test square. Test for legal move. Prepare to count exits. One exit has been found. Put KT on potential exit.

RCL^ (^'IND^(^"oO^(^SUm'^(^10 ^

^ 91 ^ (im ^G^"^^ C ° 3C 3 "^^^^ legal exit.

^SUB^

^*DSZ^ (^~0~^ 0 ^(^23 ^

Increase exit count. Next potential exit.

Listing 1 continued on page 200

198 May 1981 © BYTE Publications Inc

ENTER, THE INNOVATOR

Now You Can Access The World's

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ES^B whether you own an Apple, Atari, Commodore. Radio Shack, or other computer hardwtire system, you can now get on-line with Dow Jones Information Services.

This database is filled with reliable business

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With Dow Jones Information Services you can retrieve in-depth articles from The Wall Street Journal and Barron's; get stock quotations— just 15 rniiiutcs dela\ed—for over 6,000 companies; receive 50 key financial indicators on seleaed companies.. .even update £ind evaluate your personal portfolio! And, you can do all of this at your convenience, in the privacy of your home or office.

To make sound business and investment decisions, you need instant access to and retrieval of vital business information. With Dow Jones Information Services, you get this information—as recent as 90 seconds, as far back as 90 davs—when you need it, 21 hours a day. Plus when you get on-line v/ith Dow \' Jones, there's no minimum access charge or subscription fee.

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Listing 1 continued:

041 2 ^ ^^"T^(^+/-^(^SUM^ (^10 ^ Return KT to test square.

046 (\ci/) (^"so"^^^l^sT^ (^^£L^ C1L3 ^ ° 3C 3 ^^^'^ ninlnuin.

05 A ^ STO ^ ^ 50 ^ ^RCL ^ 1° ^ (^STO ^ (^oj Mew minimuin and position.

060 (^*CP^

061 . ^^DSZ^ C ^ C°~3 C °^ ^^^^ ^^^^ square.

Return KT to last square. 070 ^RCL^ ^ 10 ^ C"~~^ (^RCl"^ C ^° 3 CT-^ (j^^'x=t^ C ^ ^O"^ no move possible.

079 • (^RCL^ ^*IND^ 10 ^ ^STO ^ (j'^IND^ 20 ^ (^RClJ) (^20 ^

Move knight.

090 ( RST 1 Look for further moves.

091 (rcl) (^7o~^ C ^) (°) CiZ) C^l)

C ^ C"^"'^^C 3C°^ 3 ■'■^^'^ ^"'^ correct range.

105 (^RCL^ (j'^mT) 10 ^(^--^CP^(^INV^(^"sUB^ Return 0 for legal move.

109 ^"LBL^ B ^ Prepare board for tour.

I (T) (V) (TT)

••'■■CMS

(^ 00 ^ (^SUM ^ 00 ^ (^^T) 0 ^ (3Z) C "^^ 3 ^^^^ border squares.

130 (^ 2 3C^^^°3C 3C^™3C"°OC ^ 3C 3 C 3

^STO^^ 05 ^(^^7^(^STO^ (\)4^(^~7~^(^ STO^ ^ 02 ^

(^STO^ (^"oej^^ 2 1 ^ (^^-/-^ (^ST0^(^ 08 ^ Load jump increments.

153 (^CLR^(^^R/S^

155 ("LBL )( C J Make first move.

)(^ 10 3 (^STO^ (^7o~^ 1 ^^STO^^'^'IND^^IO ^C^^''^^ Begin search. 165 (j^LBL^ ^jD^^^''Fix^(2j Display Routine.

169 8 ")(3to^(^ 00 ^ Prepare row index.

172 8 ^(^STO^ ^ 09 ^ Prepare column Index.

175 (^RCL^(^Oo)(^ X ^(^ 1 3(^0j(^ + 3C^^^3C"°0

RCL ) ( *IND ) ( 89 ^ ^

Display "square.move".

^ 0 ^ ^ = ^ ^ause^ (pause^ (pause^ ^"Prt^ 198 (^---DSZ^ (~9~^(^ 1 75 ^(*kd^ Next column

203 fisr)(~0~}( 1 )( 72 ^ Next row.

207 ^CLR^ ^INV^ (j^'Fix^(^R/7^

200 May 1981 © BYTE Publications Inc

The tool you need to chop your software backlog can be yours now

/—

TRAM Drastically Cuts Development Time and Can Increase Your Productivity by 2000°/c

TRAM is an advanced TRansaction Access Method developed in PL/I to run on a variety of CPU's and operating systems. With its screen manager, you are completely freed from the burdens of screen communication such as location, length, rendition and even text itself. In addition, TRAM takes care of full data validation, default value generation and housekeeping of past values.

Look at what TRAM can do for you:

'010111 will assist you in design:

TRAM forms, kept with your specifications, describe in detail the layout, along with the information and processing required to get and validate data. This documentation is of tremendous help when modification is required.

As an option, TRAM provides a multiple-level up-and-down generalized menu and chaining system allowing you to create treestructured applications along with parameter passing.

ifHQlH will boost your productivity:

TRAM takes care of line-column

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TRAM has a unique "no show"

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TRAM has a powerful exception

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protected areas and echoing.

TRAM formats and redisplays accepted

data. TRAM retains past values

for each item. TRAM builds default

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TRAM checks input for consistency,

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All those benefits lead to a deep reduction in the actual number of lines you have to code.

will give you environment freedom:

All TRAM features can be used on any display video terminal with cursor addressing. TRAM will also work on a variety of CPU's and operating systems from micros to minis and even mainframes. Any displayable text is program independent and can be in any foreign language. Even more, the date format can be any arrangement of day, month and year, with or without month spelling. And the decimal point is what you want it to be. The

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So act now to see how TRAM will solve your problem. Concentrate on your application, TRAM concentrates on the technical burden.

TRAM is available now for Z80, 8080 CP/M and MP/M systems with 48K minimum and requires the PL/1-80 compiler (or the PL/1-80 run-time library if your application is not in PL/I).

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menu option gives you drive independence: programs, parameters and data files are freely scattered on different disk drive, with run-time choice.

CHECK IT BEFORE YOU BUY

Ask for the demo kit and you will see how a 2000 line program is reduced to 100. Send the coupon below, along with $50 and here is what you get:

• The screen generator and editor. You will immediately start creating and editing your own screens.

• The screen examiner. You will display and examine your new screens and see TRAM features at work.

• The utility programs you need to adapt TRAM to your environment.

• The demo program with source listing and documentation.

• The full TRAM screen manager manual set.

• A sample of TRAM screen forms.

The demo kit is for Z80, 8080 CP/M based systems with a minimum of 48K and comes on an 8" single side single density soft sectored diskette. TRAM'S screen manager price is $295 and can be yours for $245 if bought less than 30 days after the demo.

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Qty. Price ea.

□ TRAM'S screen manager (disk & doc) $295

+ code file option 75

+ menu option (with doc) 100

□ TRAM'S menu system alone 150

□ TRAM demo kit 50

□ TRAM'S screen manager - documentation only 30

□ TRAM'S menu system - documentation only 20

□ PL/I compiler & run-time library (disk & doc) 500

□ PL/I run-time library (disk & doc) 100

PA residents add 6% tax

o

shipping and handling r.

TOTAL

I understand ttiat if I decide to buy TRAM'S screen manager in less ttian 30 days after ttie demo. $50 credit will be applied towards the total amount. I understand also Itiat a signed software license agreement is required and that purchase price includes a 6 month maintenance and update period. Send check or money order to Reddox Corporation, Dept. B1 - 215 Chapel Crest Terrace, Pittsburgh, PA 15238

NAME

ADDRESS

CITY STATE ZIP

REDDOX CORPORATION

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BYTE May 1981 201

#13 SORWARE

1/^ out our new items.

CP/M users: specify disk systems and formats. Most formats.available.

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COMPLETE BUS. SYSTEM

Creator. . .' $269/$25

Reporter $169/$20

Both $399/$45

COMPUTER CONTROL

^ Fabs $159/520

UltraSort II $159/$25

COMPUTER PATHWAYS

Pearl (level 1) $ 99/$25

Pearl (level 2) $ae9/$40

Pearl (level 3) $549/$65

DIGITAL RESEARCH

CP/M 2.2

NorttiStar $149/$25

TRS-80 Model II (P&T).$159/$35

Micropolis $169/$25

Cromemco $189/$25

PL/1-80 $459/$35

BT-80 S179/$25

Mac S 85/$ 15

Sid $ 65/$15

Z-Sid $ 95/$15

Tex $ 70/$15

DeSpool $ 50/$ 10

DYNAMIC MICROPROCESSOR ASSOC.

Ascom $109/$ 15

CBS $369/$45

^ DMA-DOS $179/$35

GRAHAM-DORIAN

..'General Ledger $729/$40

Acct Receivable $729/$40

Acct Payable $729/$40

Job Costing $729/$40

Payroll $493/$40

Inventory $493/$40

Casti Register $493/$40

Apartment Mgt $4g3/$40

KEY BITS

String/8D $ 84/$20

String/80 (source) $279/$na

WordSearch $179/$25

MICRO-AP

S-Basic $269/$25

Selector III $269/$25

Selector IV $469/$36

MICRO DATA BASE SYSTEMS

HOBS. $269/$35

MDBS $795/$40

^ DBS or QRS or RTL $269/S35

^ MDBS PKG $1295/*e0

MICROPRO

WordStar $324/$60

^ Customization Notes... .$ 89/$na

Mail-H/lerge. $1l4/$25

WordStar/Mail-Merge... $434/$85

I.' DataStar $249/$60

WordMaster $119/$40

SuperSort I $i99/$40

MICROSOFT

Basic-80 $294/$30

Basic Compiler $329/$30

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Macro-80 $144/$20

Edit-80 $ 84/$20

IVluSimp/Mulvlath $224/$a5

MuLisp-80 $174/$20

ORGANIC SOFTWARE

TextWriter III $111/$20

DateBook $269/$25

OSBORNE

General Ledger $ 59/$20

Acct Rec/Acct Pay $ 59/$20

Payroll w/CosI $ 59/$20

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All 3 + CBASIC-2 $199/$71

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General Ledger $399/$40

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Property Mgt $799/S40

CPA Clieni Write-up $799/$40

Mailing Address $349/$40

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Adapt $ 69/$ na

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MatchMaker $ 97/$20

Worksheet $177/$20

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GLorAR or AP or Pay.. .$599/$40

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^ Diagnostic II $ 84/$ 20

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"C" Compiler $600/$30

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Condor $599/$30

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y' Pascal/Z $349/$30

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SpellGuard $249/$25

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TinyC $ a9/$50

Tiny "C ■ Compiler $229/$50

CBASIC-2 $ 89/$ 15

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MicroStat $224/$15

Vedit $ 99/$ 15

Prof Time Bill (Asyst).... $549/$40

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Softcard $292

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PERSONAL SOFTWARE

Visicalc $122

CCA Data Mgr $ 84

Desktop/Plan $ 84

Zork $ 34

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General Ledger $224/$40

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Acct Payable $224/$40

Payroll $224/$40

Inventory $224/$40

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Desk-Top Wonders.

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38

0

39

-s

40 -8

41

0

42

0

43

0

44

0

45

0

46

0

47

0

48

Q

49

- 8

50 -8

51

0

52

0

53

0

54

0

55

0

56

0

57

0

58

0

59

-8

60

-8

61

0

62

0

63

0

64

0

65

0

66

0

67

0

68

0

69

-8

70

-8

71

0

72

0

73

0

74

0

75

0

76

0

77

0

78

0

79

-8

80 -8

ei

0

82

0

83

0

84

0

85

0

86

0

87

0

88

0

89

0

Figure 1: Register initialization assignments. The values are assigned as shown for an Shy 8 playing area. Usable squares are identified by a zero value; the board size can be reduced by manually assigning nonzero values to eliminate squares.

II

1

12

20

13

9

14

14

15

3

21

10

22

15

23

2

24

19

25 24

31

21

32

8

33

23

34

4

35

13

41

16

42

II

43

6

44

25

45

18

51

7

52 22

53

17

54

12

55

5

Figure 2: Example of a reduced-size board. The Knight tour shown here is the result of KTTOUR-59's version of the Rule of Wamsdorf applied to a starting position of 11.

Text continued from page 198:

ferent tour, press B, enter a new starting position, and proceed as before.

The program execution can be modified to find tours on subsets of the 8 by 8 board. Press B as before. Then enter a nonzero value (say 1) into any square you wish to eliminate before entering the initial square and pressing C. This works since the Knight is not allowed to move to squares containing a nonzero value. For example, press B and then store the value 1 into registers 16, 17, 26, 27, 36, 37, 46, 47, 56, 57, 61 thru 67, and 71 thru 77. Enter the initial position of 11 and press C. The result will be the 5 by 5 tour shown in figiu-e 2. ■

Acknowledgments M Kraitchik, le Probleme du Cavalier, Gauthiers-VUlars et C", Paris, 1927.

Thanks are also due Professor William Woodruff, Grand Rapids, Michigan.

202 May 1981 © BYTE Publications Inc

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BYTE May 1981 203

An Integer Math Package for the 8080

Bruce D Carbrey 109 Bucknell Trl Hopatcong N] 07843

"How can you have a computer that doesn't know how to multiply?" People unfamiliar with microcomputers ask this question incredulously whenever I describe the limitations of arithmetic on my 8080-based system. Of course, if you work in BASIC, you may take arithmetic for granted; but if you are an assembly-language user like myself, you are probably painfully aware of the absence of 16-bit arithmetic on the 8080 microcomputer.

It is quite possible that you need multiple-byte arithmetic routines for your assembly-language programs. If program space is a problem (most floating-point routines use several K bytes of memory), or if 16-bit signed integer arithmetic is sufficient for your needs, then the arithmetic routines given in this article may be of interest. These routines run one order of magnitude faster than full floating-point routines; also, they occupy only 215 bytes, all of which may be in read-only memory if desired.

Two additional routines provide conversion between ASCII (American Standard Code for Information Interchange) decimal character strings and the signed binary notation

used by the arithmetic routines. These routines require an additional 175 bytes, including 2 bytes that must be in programmable memory.

Improve your 8080-based personal computer by adding these 16-blt arithmetic routines.

Design of the Arithmetic Routines

The arithmetic routines (given in listing 1) use the HL register pair as

a 16-bit wide "accumulator." Subroutines performing dyadic operations (ie: those with two operands) expect to find one operand in the HL register pair and the other in the DE register pair. The result is returned in the HL pair. The arithmetic subroutines also set the sign and zero flags to reflect the value of the result returned in the HL register pair. (For example, if the result of an operation is decimal —11034, then the minus flag will be set and the zero flag will be cleared.) The information in the carry flag is invalid and should be ig

nored. The B, C, D, and E registers are restored by all routines except EDIVMOD (the division routine), which returns the quotient in the HL register pair and the remainder in the DE register pair, with the B and C registers restored.

Internally, values are represented in two's complement form, with the most significant bit acting as a sign bit. (See text box on page 225.) This representation is a simple extension of the 8-bit representation used for normal accumulator operations.

Unfortunately, this also leads to one small anomaly. The smallest representable number is —32,768, but the largest is only -1-32,767. (See the text box on page 226.) Thus, if you negate the value —32,768, an overflow will result. As a consequence of this fact, you may add or subtract two values that give a result of exactly —32,768, but if you try to multiply or divide two numbers that will yield an answer of exactly — 32,768, an overflow will result because the mtiltiply and divide routines work on absolute values internally.

All operations, including the string-to-numeric conversions, will Text continued on page 226

204 May 1981 © BYTE PublicaUoiw Inc

NO MEMORY FERITY?

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BYTE May 1981 205

FORTRAN IV

for CP/M

"I needed a FORTRAN with COMPLEX as well as REAL and DOUBLE precision arithmetic, that would produce relocatable code and link in assennbly language subroutines. It also had to be a FORTRAN that was easy to use as well as being a connplete implementation. SuperSoft/SSS FORTRAN is the only microcomputer FORTRAN that met my requirements."

Supersoft makes full WATFIV FORTRAN IV available to microcomputers. Supersoft/SSS FORTRAN meets and exceeds the ANSI 1966 standard. The compiler supports many advanced features including: variable character strings and recursive subroutines with static variables. Fully compatible RATFOR is also available.

FEATURES

Code ROMable ".COM" files or

generation: intermediate code files (saves disk space). External routines may be called.Relocatable format.

Data types: Byte, integer, real, double precision, complex, logical, character and varying length strings.

Operations: All standard operations plus string comparisons, assignments, and .XOR.

Constants: Hexadecimal, decimal, and character literals with features to imbed control characters.

Statements: ANSI 1966 standard with multiple statement lines.

Controls: Map, List, and Symbol table output options.

I/O: Read, Write, Append, Re

wind, Close, Delete, Rename, Search, Sequential and Random I/O on disk files. Supports all CP/M devices.

System Requirements & Prices

SSS FORTRAN requires a 32k CP/M

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SuperSop

First in Software Technology

Listing 1: 16-bit arithmetic subroutines in 8080 assembl}/ language. The eight routines, which are fully documented in the listing, operate on 16-bit numbers in two's complement form.

43 ORG 4000H

• ••••• EXTENDED ARITHMETIC SUBROUTINES FOR 8080 COMPUTERS ••••• ♦

• . . •

• WRITTEN BY BRUCE D. CAR8REY REVISION 0 SEPT.. 1977 •

• •

• THESE ROUTINES EXTEND THE ARITHMETIC CAPABILITIES OF ♦

• THE 8080 MICROCOMPUTER TO INCLUDE INTEGER ARITHMETIC « » ON SIGNED* 16-BIT QUANTITIES. USING BINARY, TWOS-COMPLEMENT • » ARITHMETIC. THE RANGE OF PERMISSABLE VALUES WITHOUT #

• OVERFLOW IS •

• -32767 TO ♦32767 • » DECIMAL. TO USE A MATH ROUTINE. •

• SIMPLY LOAD THE REGISTER(S) INDICATED WITH THE OPERANO(S). • » AND CALL THE APPROPRIATE ROUTINE. THE ANSWER WILL BE • » RETURNED IN THE REGISTER(S) INDICATED. THE SIGN (S) AND •

• ZERO (Z) FLAGS WILL BE SET TO REFLECT THE VALUE OF THE •

• RESULT IN THE SAME WAY AS FOR AN ORDINARY 8-BIT ADD. •

• LOGIC IS PROVIDED FOR DETECTING OVERFLOW FOR ALL OPERATIONS. •

• WHICH RESULTS IN A CALL TO A ROUTINE NAMED OVERFLOW •

• ( WHICH IS NOT SUPPLIED SINCE YOU MUST DECIDE WHAT YOU •

• WANT TO 00 IN CASE OF OVERFLOW PROBABLY PRINT A MESSAGE •

• AND JUMP TO YOUR MONITOR). «

• •

• IN ADDITION TO THE MATH OPERATORS. TWO UTILITY SUBROUTINES •

• ARE PROVIDED FOR STRING-NUMERIC AND NUMERIC-STRING CONVERSION. •

ENTRY SUBROUTINE FUNCTION

• •

• •

• EADO (HL) = (HL> ♦ <DE) •

• ESUB (HL) = (HL) - (DE) •

• EMULT (HL) = (HL) • (DEI • « EDIVMOD (HL) = (HL) / (OE). AND (OE) = (HL) MOD (OE) • « ESIGN SET (S), (Z) FLAG TO REFLECT (HL), LEAVING (HL) •

• UNCHANGED. •

• ECMP SET (S), (Z) FLAGS TO REFLECT (HL) - (DE), LEAVING •

• (HL) AND (0E> UNCHANGED. •

• •

• DECBIN CONVERT ASCII CHARACTER STRING REPRESENTING A SIGNED •

• DECIMAL INTEGER TO A SIGNED BINARY NUMBER. »

• BINOEC CONVERT A SIGNED BINARY NUMBER TO AN ASCII STRING •

• REPRESENTING THE SIGNED DECIMAL VALUE OF THE NUMBER. •

• •

89 • MATH PACKAGE EXECUTION TI^ES IN MICRO-SECONDSl

90 •

91 • ROUTINE TYPICAL WORST CASE

92 •

93 • EADD 30 54

94 » ESUB 50 74

95 • EMULT 370 517

96 • EDIVMOD 680 2500

97 *

98 •

99 • •»••• YOU MUST PROVIDE PATCHES TO THESE TWO ROUTINES...

100 •

101 OVERFLOW ECU 0 WHERE TO GO AFTER OVERFLOW

102 CONVERR EQU 0 WHERE TO 60 ON STRING-NUMERIC ERROR

103 •

» •

• SUBROUTINE EADO - ADD (HL) TO (DE). RESULT TO (HL) •

106

«

(HL) = (HL) ♦ (DE)

107

•

ON RETURN,

SIGN, ZERO

1 FLAGS WILL REFLECT RESULT. CY CLEARED.

108

•

A REGISTER

CLOBBERED.

B. C. 0. E REGS RESTORED.

109

•

116

4000

7C

EADO

MOV

A.H

TEST IF SIGNS ARE SAME OR DIFFER...

111

4001

AA

XRA

D

112

4002

E680

AN I

80H

113

4004

19

DAD

D

ADD, WITHOUT AFFECTING ZERO FLAG...

114

4005

C20E40

JNZ

ESIGN

SKIP OVERFLOW TEST IF SIGNS DIFFER

115

400B

IF

RAR

TEST FOR OVERFLOW BY...

Listing 1 continued on page 212

Mqr 1981 ©BYTE Publication Inc 207

DIGITAL HARMONY

by John Whitney

A new synthesis of sight and sound .

Digital Harmony lays the foundation for the whole new field of audio-visual art mode possible by microcomputers. John Whitney, a pioneer of the special effects technology used in STAR WARS and 2001: A SPACE ODYSSEY, explains the special union of computer grophics and music. His computer-generated visual art graphically depicts the laws of harmonic motion common to all music.

Digital Harmony includes a complete description of Whitney's computer, peripherals, and film techniques. Colorful illustrations are included, as well as the program listings that generated them. The descriptions are sufficient for anyone to begin to explore this new territory as a composer and computer experimenter - transforming the small computer into an ideal instrument for creating compositions in aural and visual art,

John Whitney is on the Faculty in the Department of Art at the University of Californio, Los Angeles.

ISBN 0-07-070015-X 240 pages hardcover

over 50 color ^ 91 AC photographs ^ 4a I ■ 7 9

A Catalogue of

Calligraphic

Cartwheels

by Scott Kim

Foreword by Douglas Hofstader Backword by Jet Raskin

Surprising symmetries in design and letterforms

Illusion ... calligraphy ... visual magic - Scott Kim's new book, Inversions, delights the eye and enchants the mind. Filled with intriguing designs! words that read the same rightside up and upside down, words within words, and unexpected symmetries, these compositions create a fresh way to look at the alphabet. The text includes the visual principles of symmetry, lettering, and problem solving that are basic to these images. The author also draws parallels to related exercises in perception in such diverse areas as art, music, word play, and mathematics. Scott Kim's original inversion designs first appeared, in Omni magazine, inspiring an overwhelming reader response. An irresistable challenge, invertible writing appeals to everyone who loves beauty in mathematics and design.

Scott Kim is a doctoral student in Computer Science at Stanford University and is a concert pianist and composer.

ISBN 0-07-034546-5 128 pages soffcover

over 50 Illustrations available summer 1981

$8.95

BRAINS, BEHAVIOR, AND ROBOTICS

by Jomes S, Albus

Robotics design and applications

This computer-oriented guide explores how the brain functions primarily as a computer device for generating and controlling behavior. The author assesses behavior as a" product of three hierarchies of computing modules:

• memory modules

• behavior-generating modules

• sensory-processing modules

A section on artificial intelligence ties this hierarchical model to vital computer science techniques such as planning, problem-solving, machine vision, natural language understanding and knowledge representation, A closing section on robotics discusses the design considerations in constructing a robot control system fashioned after this model of the brain, and explores the current and potential use of robots in our environment,

Dr, James S, Albus is Project IManager with the National Bureau of Standards,

ISBN 0-07-000975-9 400 pages hardcover 180 illustrations

$15.95

THE BRAINS OF MEN AND MACHINES

by Ernest W, Kent

Human models for computer design

When the "Brains of Men and Machines" series of articles , first appeared in BYTE magazine, the response was immediate and enthusiastic. Now Ernest W, Kent has expanded his ideas about the brain into a full-length book. As researchers begin to unravel the mysteries of the brain's chemical, electrical, and synaptic circuitry, their findings are becoming immediately applicable to advances in robotic behavior and computer design. The Brains of Men and Machines "dissects" the. brain to provide new insights into computer design and artificial intelligence.

It is one of the rare books that transcends disciplinary boundaries. In it the ever-increasing relationship between man and machine is freshly examined a relationship, Professor Kent concludes, that is today being reexamined in the light of man's own neurological self-image,

Dr, Ernest W. Kent is a Professor of Physiological Psychology and Psychopharmacology at the University of Illinois at the Chicago Circle Campus.

ISBN 0-07-034123-0 304 pages

hardcover AC illustrated ^10.79

The BYTE BOOK Collection

circle §3 on Inquiry card.

BYTE May 19S1 209

BASIC SCIENTIFIC SUBROUTINES, VOLUMES 1 AND 2

by Fred Ruckdeschel d

SuUruutTncTS Vol- I

Valuable programs for professional and hobbyist

Designed for the engineer, scientist, experimenter, and student, ttils series presents a complete scientific subroutine package in BASIC.

• Volume 1 covers plotting, complex variables, vector and matrix operation, random number generation, and series approximations.

• Volume 2 continues witl-i leost-squores approximation, special polynomial functions, approximating tectnniques, optimizotion, roots of functions, interpolation, differentiation, integration, and digital filtering.

Ttiese volumes feature routines written in botti standard Microsoft and North Star BASIC, extensive appendices, and subroutine cross-referenes.

Dr. Fred Ruckdeschel is a Principal Scientist with Dynocomp, Inc.

VOLUME 1 VOLUME 2

ISBN 0-07-054201-5 ISBN 0-07-054202-3

336 pages 384 pages hardcover

hardcover illustrated

Illustrated available Fall 1981

$19.95 523.95

fSascal THE BYTE BOOK OF PASCAL

Blaise W. Liffick, Editor

A powerful, structured language

Based on articles, language forums, and letters from BYTE magazine, this work is a valuable software resource. Pascal continues to be popular as a structured programming language. Written for both potential and established users, this book introduces the Pascal language and examines Its merits and possible implementations. Featured are two versions of a Pascal compiler, one written in BASIC and the other In 8080 assembly language: a p-code Interpreter written in both Pascal and 8080 assembly language; a chessplaying program; and an APL interpreter.

ISBN 0-07-037823-1 334 pages

hardcover

$25.00

THREADED

INTERPRETIVE

LANGUAGES

by Ronald Loeliger ,

How to implement FORTH on your Z80

Threaded languages (such as FORTH) are compact, giving the speed of assembly language with the programming ease of BASIC. They combine features found in no other programming languages. This book develops on interactive, extensible language wifh specific routines for the Zilog Z80 microprocessor. With the core interpreter, assembler, and data type defining words covered in the text, it is possible to design and implement programs for almost any application and equivalent routines for different processors.

Ron Loeliger is a Senior Analyst with Intermefrics, Inc.

ISBN 0-07-038360-X 272 pages hardcover Illustrated

$18.95

BEGINNER'S GUIDE FOR THE UCSD PASCAL - SYSTEM

by Kenneth L. Bowles

The most popular Pascal version explained by its creator

Written by the originator of UCSD Pascal System, this informative book is an orientation guide to the UCSD Pascal System, For the novice, this book steps through the System, bringing the user to a sophisticated level of expertise. Once familiar with the System, the reader will find the guide an invaluable reference tool for creating advanced applications. The package offers programs which may be run without alteration on:

• DEC PDP-11 or General Automation minicomputers

• Western Digital Microengines

• 8080, 8085, Z80, 6502, 6800, 9900 or AM-lOO based microcomputers (including the popular Apple II and Radio Shack TRS-80 microcomputers)

Dr. Kenneth L. Bowles is Director of the Institute for information Systems, University of California, San Diego.

ISBN 0-07-006745-7 204 pages softcover

$11.95

YOU JUST tI; BOUGHT A PERSONAL I/I/HA7"?

by Thomas Dwyer and Matgot Crltehfleld

A Structured Approach to Creative Programming

Intended for both the novice programmer and the experienced computer enthusiast, this book presents practical ideas for personal computer use at home or at wort

Its approach is especially suitable for educational purposes. Written by the leading contributors of computer education material, this book Is an entertaining and resourceful tool. There are over 60 ready-to-use programs written in Microsoft and Level II BASIC for the TRS-80 in the orec of educational gomes, financial record keeping, business transactions, diskbased files, and word processing,

Dr, Thomas Dwyer is a Professor of Computer Science at the University of Pittsburgh.

Margot Critchfield Is a doctoral student in Foundations in Education at the University of Pittsburgh.

ISBN 0-07-018492-5 343 pages softcover 78 illustrations

$11.95

BEYOND GAMES SYSTEIV SOFTWAR FOR YOUl 6502 PERSONAL COMPUTER

by Kenneth Skie

Creating programs for the Apple, Atari, Challenger and PET computers

At lost, a complete programming guidebook for owners of personal computers utlllang the 6502 microprocessor. A selfcontained course in structures programmini and top-down design, this book presents a powerful set of tools for building on extended monitor, disassembler, hexadecimal dump routine, and text editor programi Programs are thoroughly explained, with clear instructions for modifications.

Kenneth Skier is a Systems Programmer for Wong Laboratories, Inc., and o Lecturer at MIT

ISBN 0-07-O57860-5 440 pages softcover illustrated

$14.95

stimulating, provocative, problem-solving

210 BYTE May 1981 Circle 54 on Inquiry card.

CIARCIA'S

CIRCUIT

CELLAR

by Steve Ciarcia

Practical uses for home computers

Imaginative and practicai, Cicrcia's Circuit Celiar details a variety of microcomputer projects. A coiiection of ttie best articles from the popular series in BYTE magazine, this volume includes

• D/A conversion

• Programming EPROMS

• AC remote-controlled appliances

• digitized speech

• touch input video display

Complete instructions ore given on hov*/ to construct eoch project. With amusing anecdotes and on easy-going style, Ciarcia presents his material in such a manner that even a neophyte need not be afraid of it.

ISBN 0-07-010960-5 125 pages softcover

color photograjjhs and diagrams

$8.00

CIARCIA'S CIRCUIT CELLAR, VOLUME II

by Steve Ciarcia

More practical uses fpr tiome computers

Composed of popular articles from BYTE magazine, this volume tells how microcomputers can be uniquely interfaced to our environment. Projects include

• building a computer controlled homesecurity system

• computerizing appliances

• transmitting digital information over a beam of light

• building the Intel 8086 microprocessor system design kit

• input-output expansion for the TRS-80

ISBN 0-07-010963-X 224 pages softcover

photographs and diagrarm

$12.95

MICROCOMPUTER STRUCTURES

by Henry D'Angelo

Digital Electronics, Logic Design, and Computer Arctiltecture

Today, there is an Increasing demand for computer users who are not only vt^ell-versed in softvi^are, but v»/ho can also maintain, modify, and design their own hardware systems.

This text introduces computer users with little or no background in digital hardware to the basic computer structures used In

microcomputer design and microcomputer interfacing. Helpful examples and end-ofchapter exercises further illustrate the various concepts presented, and a detailed bibliography provides additional reading opportunities. As a resource and textbook, it will assist

• programmers and systems analysts

• engineers and scientists

• managers

• students

Detailed Instructor's Manual also available.

Dr. Henry D'Angelo is the Associate Dean of the College of Engineering and Professor of Manufacturing Engineering of Boston University.

ISBN 0-07-015294-2 288 pages hardcover 314 illustrations available spring 1981

$18.95

Instructor's Manual ISBN 0-07-015298-5 softcover

$8.95

BUILD

YOUR OWN Z80

COMPUTER

by Steve Ciarcia

"^.t/IUO YOIJH OWIS4

Every step spelled out for do-it-yourself buffs

For the engineer, computer technician, student, and anyone interested in building a computer rather than buying one, this practical guide shows how to build a working computer based on the ZIlog Z80 microprocessor. Each computer subsystem is fully explained and supported by proven design and testing information. The description focuses on o basic single-board microcomputer containing

• easy expansion to include a video terminal

• a 1 K-byte operating system

• serial and parallel ports

• hexadecimal display

• audio cassette mass storage

Readers can modify the system to meet personal needs.

Steve Ciarcia is a Computer Consultant, Electrical Engineer, and author of "Ask Byte" and "Ciarcia's Circuit Cellar" columns In BYTE magazine.

ISBN 0-07-010962-1 330 pages softcover

available summer 1981

$15.95

BYTE Books' reputation is based

on providing technically accurate, useful, and timely information. Established on the same principle as BYTE magazine, BYTE Book's evolved in response to the rapidly expanding audience of home and business computer users. Computer professionals and enthusiastic newcomers need to keep pace with this unabated growth. This selection of BYTE books can expand your library of knowledge and expertise.

TO ORDER, CALL TOLL FREE 8OO-258-5420, OR FILL OUT YOUR CHOICES IN THIS COUPON and return it with ctieck, money order, or charge card number to:

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BYTE May 1981 211

Listing 1 continued from page 206:

116

4009

AC

XRA

H ...EXCLUSIVE OR OF CY AND SIGN OF RESULT

117

400A

17

RAL

UB

400B

DCOOOO

CC

OVERFLOW CHECK FOR ARITH OVERFLOW

119

♦

FALL THRU TO

« « •

SUBROUTINE ESIGN

«

SET (S). (Z) FLAGS TO REFLECT (HL) •

«

122

•

123

• A REGISTER

CLOBBEREDt ALL OTHERS RESTORED.

IZU

•

125

400E

AF

ESI6M XRA

A CLEAR FLAGS

126

400F

84

ADD

H SET FLAGS TO REFLECT HI BYTE

127

4010

CO

RNZ

RETURN IF HI-ORDER BYTE IS NON-0

128

4011

85

ADD

L ELSEt SEE IF L IS 0 TOO...

129

4012

C8

RZ

AND IF S0« RETURN

130

4013

AF

XRA

A ELSEt FORCE FLAGS TO SHOW *

131

4014

3C

INR

A

132

4015

C9

RET

» SUBROUTINE ESUB - SUBTRACT (DE) FROM (HL)• RESULT TO (HL)

1 3Q

•

CHL) = (HL) - (DE)

1 JO

»

ON RETURN•

ZERO, SIGN FLAG REFLECT RESULT. CY CLEARED.

1 "17 1 J r

A REGISTER

CLOBBERED. Bf C, D, E RESTORED.

138

•

139

4016

05

ESUB

PUSH

D

140

4017

EB

XCHG

141

4018

CD3040

CALL

COMP? FORM 2S COMPLEMENT OF SUBTRAHEND...

142

401B

CD0040

CALL

EADO ...AND PROCEED AS IN ADDITION

143

401E

Dl

POP

D

144

401F

C9

RET

» • •

ECHS

CHANGE SIGN OF REGISTER (HL»

147

•

(HL) = -(HL)

148

•

ON RETURN.

ZERO, SIGN FLAG REFLECT RESULT. CY CLEARED.

149

«

A REGISTER

CLOBBERED. B, C, D. E RESTORED.

150

»

151

4020

7C

ECHS

MOV

A.H

152

4021

D680

SUI

BOH CHECK FOR THAT ONE NASTY CASE...

153

4023

C22A40

JNZ

ECHSGO ...OF (HL) = EXACTLY -32768...

154

4026

85

ADD

L ...WHICH CANT 3E COMPLEMENTED RIGHT

155

4027

CCOOOO

CZ

OVERFLOW ...AND WHEN DETECTED, ABORT

156

402A

CD3040

ECHSGO

CALL

C0MP2 ELSE» FORM 2S COMPLEMENT IN (HL)

157

402D

C30E40

JHP

ESIGN SET FLAGS AND RETURN

158

•

159

•

SUBROUTINE

C0MP2 - FORM 2S COMPLEMENT OF (HL)

160

«

161

4030

70

C0MP2

MOV

A,H

152

4031

2F

CMA

163

4032

67

MOV

H«A

164

4033

70

MOV

A,L

155

4034

2F

CMA

166

4035

6F

MOV

L.A

167

4036

23

INX

H

168

4037

C9

RET

• SUBROUTINE EMULT - MULTIPLY (HL) BY (0E)» RESULT TO (HL)

171 172

(HL) = (HL) • (DE)

ON RETURN, ZERO, SIGN FLAG REFLECT RESULT. CY CLEARED.

Listing 1 continued on page 214

212 M«y 1981 ® BYTE Publicatioiu Inc

THE ORIGINAL MAGAZINE FOR OWNERS OF THE TRS-80 MICROCOMPUTER

* TRS-80'" IS A TRADEMARK OF TANDY CORP.

SOFTWARE FOR TRS-80'" OWNERS

H

CQIYIPUTHQI^ICS

I MONTHLY

NEWSMAGAZINE

c.

FOR TRS-80'" OWNERS

MONTHLY NEWSMAGAZINE

Practical Support For Model I, II & III

• PRACTICAL APPLICATIONS

• BUSINESS

• GAMBLING • GAMES

• EDUCATION

• PERSONAL FINANCE

• BEGINNER'S CORNER

• NEW PRODUCTS

• SOFTWARE EXCHANGE

• MARKET PLACE

• QUESTIONS AND ANSWERS

• PROGRAM PRINTOUTS AND MORE

NOW IN OUR 4th YEAR

PROGRAMS AND ARTICLES PUBLISHED IN RECENT ISSUES INCLUDE THE FOLLOWING:

• FINCALC ■ A COMPLETE FINANCIAL APPUCATIONS PACKAGE

• INFORMATION SYSTEM REVIEW

• STATISTICAL COMBINATIONS

• PASCAL'S TRIANGLE

• ASSEMBLY LANGUAGE FOR BEGINNERS

• DISK FILES

• MOD-III REVIEW

• KEYBOARD THUNDER AND LIGHTING EXPLAINED

• DOS COMMANDS IN LEVEL II

• PROBABILITY CURVE GENERATOR

• CALCULATOR SIMULATIONS

• THE MEGABYTE GAP

• STOCKS AND BONDS

• BUDGET ANALYSIS (FOR BUSINESS AND HOME)

• NEWDOS/80 REVIEW

• DUTCHING - THE HORSE SYSTEM THAT CAN'T LOSE

• A SIMULATED GOLF GAME

• CONTINUOUS FORM SOURCES

• TAX/SAVER REVIEW AND MORE

FINCALC

^ A Complete Financial Analysis Package Used

" -oaQ^^ Calculate Markup, Margin, Annuities, Compound Interest, Nominal

^'^'^ Effective Rates, Sinking Funds, Mortgage Calculations, Future Value, <l4t''^^^ Savings and Insurance, Percentage Difference Between Two Numbers, Amortization Schedule and More

SEND FOR OUR NEW 64 PAGE SOFTWARE CATALOG (INCLUDING LISTINGS OF HUNDREDS OF TRS-80'" PROGRAMS AVAILABLE ON

CASSETTE AND DISKETTE). $2.00 OR FREE WITH EACH SUBSCRIPTIONS OR SAMPLE ISSUE

All programs are supplied on cassette (add $3 for Diskette Version - add $5 for modified Mod-U Version).

I

N

C.

50 N. PASCACK ROAO SPRING VALLEY, NEW YORK 10977

ONE YEAR SUBSCRIPTION $24

TWO YEAR SUBSCRIPTION $48

SAMPLE OF LATEST ISSUE $ 4

START MY SUBSCRIPTION WITH ISSUE

(#1 • July 1978 • #12 - June 1979 • #24 - July 1980 ' NEW SUBSCRIPTION RENEWAL

NEW TOLL-FREE

ORDER LINE

(OUTSIDE OF N.Y. STATE)

(800) 431-2818

HOUR 24 ORDER LINE

(914) 425-1535

#30 ■ January 1981)

CREDIT CARD NUMBER. SIGNATURE

_EXP. DATE

NAME _

ADDRESS

_CITY_

_STATE.

.ZIP.

"* ADD $12/YEAR (CANADA, MEXICO) - ADD $24/YEAR AIR MAIL - OUTSIDE OF U.S.A., CANADA & MEXICO ***

Circle 171 on inquiry card.

BYTE May 19n 213

Listing 1 continued:

1 71

1 f J

•

A REGISTER

CLOBBERED. B. C, 0, E RESTORED.

If*

1 f 3

C5

EMULT

PUSH

R

1 fb

ns

PUSH

D

1 77 Iff

/i n A

C06F40

CALL

pel T^sTf^N

riNrt RF^^iii T <;Tr^N. aB^: v/ai nF nPFOAunQ

178

40 30

AF

XRA

179

403E

84

ADO

H

1 fin

&.n IF •f U Jr

CA4840

JZ

Ul CUAI 1

MLSMALL

DDAUf^U TP #ul 1 1 FCC TUAAI Q QTTC

DKANun xr tHLI InAN O Ollb

1 ft 1

1 d1

AF

XRA

A

1 Q9

R2

ADD

D

ELaE* OTHER Or nUai BE .LT. B BITS...

1 Rt

1 ES J

C40000

CNZ

UvtKr L.UN

no niiFDCi nu umii n dfciii t

1 O/.

4047

EB

XCHG

(HL) NOW HAS AM OP WITH .LT. 8 BITS

185

4048

70

HLSMALI

MOV

A»L

MOVE 8-BIT OR LESS MULTIPLIER TO A

1 Q <^

1 oo

210000

LXI

H f 0

INITIALIZE PARTIAL rRODUCT

1 R7

1 D r

4 04C

37

XMLOOP

STC

Tl PAS PADDV

1 88

4040

3F

CMC

189

404E

IF

RAR

DflTATF Mill TTPI TF(? fJTTF flFF Fun

1 Qn

404F

D25640

JNC

CU T F TriD

on1r1u"

IF QTT Cl-I T F TF n_ni 1T UAC n- CKTD

X 7 1

19

OAO

n u

Fi ■ Ann Mill TTPI TrAAin Tn dadttai Donn

192

4053

DCOOOO

CC

193

4056

EB

SHIFTOP

XCHG

194

40S7

29

DAD

^HTFT Mill TTDI TTAMD 1 FFT 1 OTT

195

405B

DCOOOO

CC

y^iTi F rwFncTMA fop oufpfi nu

196

405B

FB

XCHG

1 Q7

405C

B7

0R&

A

1 QA

40 50

C24C40

JNZ

QDAkjr'i-i Tn TnD r»F 1 nno ic uiii r tc aiaai a

1 99

4060

Dl

POP

0

WHEN MULTIPLY DONE, RECALL (DE)

200

4061

7C

SIGNPCL

MOV

A'f M

201

4062

07

RLC

MAKE rINAL OVERrLOW CHECK.

cue

4063

OCOOOO

CC

OVERFLOW

FOR VALUES BETKEEN3276B AND 65535 INCLUS.

203

4066

78

MOV

A.B

THEN RECALL SIGN BYTE

204

4067

17

RAL

205

4068

00304-0

CC

C0MP2

CHANGE SIGN OF RESULT IF IT IS TO BE

c u o

ei

POP

B

?ft7

C30E40

JMP

ESIGN

SET FLAGS AND RETURN

?08

•

209 210

*

SUBROUTINE

RSLTSIGN

- COMPUTE SIGN OF RESULT FOR • AND /

211

•

ON return:

<HL) = ABSOLUTE VALUE OF (DE), (OE) = ABS. VAL JHL)»

212

•

(8) = SIGN

OF RESULT

IN MOST SIGNIFICANT BIT.

213

«

214

406F

44

RSLTSIGN

MOV

BtH

FETCH SIGN BYTE OF 1ST OPERAND

215

4070

7C

MOV

A«H

...TO B AND ALSO TO A...

216

4071

17

RAL

217

4072

DC3040

CC

C0MP2

ABSOLUTE VALUE OF (HL)

218

4075

EB

XCHG

2ND OPERAND...

219

4076

7C

MOV

A,H

SIGN BYTE TO A...

220

4077

A8

XRA

B

RESULTANT SIGN...

221

4078

47

MOV

B*A

...TO MSB OF REG B FOR LATER RECALL

222

4079

7C

MOV

A,H

SIGN BYTE OF 2*40 OP TO A

223

407A

17

RAL

224

407B

OA3040

JC

C0MP2

ABSOLUTE VALUE« THEN RETURN.

225

407E

C9

RET

* • *

sua. EOIVMOD - DIVIOE (HL) BY

<DE)« QUO. TO (HL)« REM. TO (DE)

ceo

•

ON CALL: (HL) = DIVIDEND, (DE) = DIVISOR.

«

ON return:

(HL) = QUOTIENT, (DE) = REMAINDER.

o ^ rt

230

•

FLAGS REFLECT VALUE

OF QUOTIENT. CY CLEARED.

231

•

A REGISTER

CLOBBERED

. B, C RESTORED.

232

*

REMAINDER

IS ALWAYS

POSITIVE, REGARDLESS OF SIGN OF OPERANDS.

233

•

91A.

■fu f r

C5

EOIVMOD

PUSH

B

235

4080

AF

XRA

A

IF DIVISOR = 0...

236

4081

B3

ORA

E

?17

4082

32

ORA

D

•* u o J

CCOOOO

CZ

OVERFLOW

...THEN ABORT

CD6F40

CALL

RSLTSIGN

COMPUTE RESULT SIGN: SWAP DE, HL

240

4089

7C

MOV

A,H

INSURE THAT NEITHER OPERAND...

241

408A

B2

ORA

D

...WAS THAT NASTY SPECIAL CASE...

242

40 SB

V f

RLC

...OF EXACTLY -32768...

A nop

DCOOOO

CC

OVERFLOW

...AND IF IT WAS, ABORT

244

408F

C5

PUSH

B

SAVE RESULT SIGN BYTE

245

4090

48

MOV

C,E

MOVE DIVIDEND ( = REM) TO BC

246

4091

42

MOV

8,0

247

4092

110000

LXI

D,0

INITIALIZE QUOTIENT = 0...

24S

4095

05

PUSH

0

...ON TOP OF STACK (TOS)

249

4096

EB

XCHG

NOW BC = REM. DE=DIV. TOS=QUO

Listing 1 continued on page 216

214 May 1981 © BYTE Publications Inc

H ft

E

CQniPUTHQMlCS

N

EVERYTHING FOR YOUR TRS-80* • ATARI* • APPLE* • PET* •

'TR$-80 is a trademark of the Radio ^ack Division of Tandy Corp. - *ATARI is a trademark of Atari Inc. - *Apple is a trademark of Apple Corp, - *Pet is a trademark of Commodore

BUSINESS PAC 100

'^^■^^^':X^^Ji- 100 Ready-To Run 'sor^« Business Programs

(ON CASSETTE OR DISKETTE) Includes 110 Page Users ivianual 5 Cassettes (Or Diskettes)

Inventoiy Control Payroll Bookkeeping System Stock Calculations

Checkbook Maintenance....^ccounts ReceivabIe.....Accounts Payable

BUSINESS 100 PROGRAM UST

1

D/ It C"70

Interest Apportionment by Rule of the 78 s

2

ANNUl

Annuity computation program

3

DATE

Time between dates

4

DAYYEAR

Day of year a particular date falls on

5

LhAbtilri 1

Interest rate on lease

6

bKtAPitVPi

Breakeven analysis

7

DEPRSL

Straightline depreciation

8

DEPRSY

Sum of the digits depreciation

9

DEPRDB

Declining t)alance depreciation

10

DEPRDDB

Double declining balance depreciation

11

TAXDEP

Cash flow vs. depreciation tables

12

CHECK2

Prints MEBS checks along with daily register

13

CHECKBKl

Checkbook maintenance program

14

MORTGAGE/A

Mortgage amortization table

15

MULTMOM

Computes time needed for money to double, triple,

16

SALVAGE

Detennines salvage value of an investment

17

RRVARIN

Rate of return on investment with variable inflows

18

RRCOtSST

Rate of return on investment with constant inflovw

19

EFFECT

Eifective interest rate of a loan

20

FVAL

Future value of an investment (compound interest)

21

PVAL

Present value of a future amount

22

LOANPAY

Amount of payment on a loan

23

REGwrra

Equal withdrawals from investment to leave 0 over

24

SIMPDISK

Simple discount analysis

25

DATEVAL

Equivalent & nonequivalent dated values for oblig.

26

AMNGDEF

Present value of deferred annuities

27

MARKUP

% Markup analysis for items

28

SINKFOND

Sinking fund amortization program

29

BONDVAL

Value of a bond

30

DEPLETE

Depletion analysis

31

BLACKSH

Black Scholes options analysis

32

STOCVALl

Expected return on stock via discounts dividendis

33

WARVAL

Value of a warrant

34

BONDVAL2

Value of a bond

35

EPSEST

Estimate of future eamings per share for company

36

BETAALPH

Computes alpha and beta variables for stock

37

SHARPEl

Portfolio selection model-i.e. what stocks to hold

38

OPTWRITE

Option writing computations

39

RTVAL

Value of a right

40

EXPVAL

Expected value analysis

41

BAYES

B^slan decteions

42

VALPRINF

Value of perfect Information

43

VALADIMF

Value of additional information

44

UTILITY

Derives utility function

45

Sim£X

Linear programming solution by simplex method

46

TRAMS

Transportation method for linear programmir»g

47

EOQ

Economic order quantity inventory model

48

QGEGEl

Single server queueing (waiting line) model

49

CVP

Cost volumeprofit analysis

50

CONDPROF

Conditional profit tables

51

OPTLOSS

Opportunity loss tables

52 FQCJOQ

Fixed quantity ecorramic order quantity model

rMME

DESCRIPTION

53 FQEOWSH

As above but with shortages pemiitted

54 FQEOQPB

As above but with quantity price breaks

55 QUEtlECB

Cost-benefit waiting line analysis

56

NCFATW.

Net cash-flow analysis for simple investment

57

PRORMD

Profitability index of a project

58 CAPl

Cap. Asset Pr. Mode) anatysis of project

59

WACC

Weighted average cost of capital

60

COMPBAL

True rate on loan with compensating bal. required

61

DISCBAL

True rate on discounted loan

62

MERGANAL

Merger analysis computations

63

FIMRAT

Financial ratios for a firm

fiA o**

ND\/

Met present value of project

65

PRINDL7\S

Laspeyres price index

66

PRINDPA

Paasche price index

67

SEASIND

Constructs seasonal quantity indices for company

68

TIMETR

Time series analysis linear trend

69

TIMEMOV

Time series analysis moving average trend

70

FUPRINF

Future price estimation with inflation

71

MAILPAC

/filing list system

72

LETWRT

Letter writing system-links with MAILPAC

73

SORT3

Sorts list of names

74

LABEL 1

Shipping label maker

75

LABEL2

Mame lab>el maker

76

BUSBUD

DOME business bookkeeping system

77

TIMECLCK

Computes weeks total hours from ttmeclock info.

78

ACCTPAY

In memory accounts payable system-storage permitted

79

INVOICE

Generate invoice on screen and print on printer

80

IMVENT2

In memory inventory control system

81

TELDIR

Computerized telephone directory

82

TIMUSAN

Time use analysis

83

ASSIGN

Use of assignment algorithm for optimal job assign.

84

ACCTREC

In memory accounts receivable system-storage ok

85

TERMSPAY

Compares 3 methods of repayment of loans

86

PAYNET

Computes gross pay required for given net

87

SELLPR

Computes selling price for given after tax amount

88

ARBCOMP

Arbitrage computations

89

DEPRSF

Sinking fund depreciation

90

UPSZONE

Finds CJPS zones from zip code

91

ENVELOPE

Types envelope Including return address

92

ACJTOEXP

Automobile expense analysis

93

INSnLE

Insurance policy file

94

PAYROLL2

In memory payroll ^tem

95

DILANAL

Dilution analysis

96

LOANAFFD

Loan amount a borrower can afford

97

RErTTPRCH

Purchase price for rental property

98

SALELEAS

Sale-leaseback analysis

99

RRCONVBD

Investors rate of return on convertable bond

100

PORTVAL9

Stock mari<et portfolio storage-valuation program

Circle 172 on inquiry card.

□ CASSETTE VERSION

□ DISKETTE VERSION

□ TRS-SO* MODEL D VERSION

$99.95 $99.95 $149.95

T-OLL.

FREE

ADD $3.00 FOR SHIPPING IN UPS AREAS ADD $4.00 FOR C.O.D. OR NON-UPS AREAS ADD $5.00 OUTSIDE U.S.A, CANADA & MEXICO

•CQnPUTHQMICSE

50 N. PASCACK ROAD SPRING VALLEY, NEW YORK 10977

HOUR OA OBO^^

425-1535

Listing 1 continued:

/tn07

mj'T r

91 n 1 An

1 XT

M.I

IN1TIAII7E HOLD = 1

40 9A

?9

nRrnrv dad

LEFT SHIFT HOLD

c3 J

A A OR

C. D

XCHG

A. n Qf* f U

30

c "

DAD

1 FFT "^HT FT n T V

COC940

CALL

CMPBH

COMPARE DIV TO REM

•f U HI/

XCHG

NOW SCsREMa OE=0IV« HLsHOLDi

c r

40 Al

029A40

JNC

DBLOIV

BRANCH BACK IF OIV < REM

25B

40A4

EB

XCHG

DUMMY XCHG TO MAKE LOOP WORK

1ST PASS...

40 A5

EB

HALVfDTV XCHG

NOW BC=REM« DEzDIV. HLsHOLDi

260

40 A6

CDCE40

CALL

DIVBY2

HOLD = HOLD/? (RITE SHIFT)

261

40 A9

CAC240

JZ

IF HOLD = Of WERE DONE

?AP coc

40 AC

EB

XCHG

NinU RC = RFH* nF=HOI D« HI sDlU* ''iwii o ^ ~ r\ t. n f L/L.-* (1 ij t L/? ni_ —i/AVT

C O J

40 AD

CDCE40

CALL

DIVBY2

R T TF SHT FT n T \/

COH

40B0

CDC940

CALL

CMPBH

rOMPARF niV Tfl RFM

C u3

4nB3

rAA540

JM

HAI VFDTV

TF DIV > RFm. RRANPH R&PK

266

40B6

79

MOV

4. r

RFM = RFM —

267

40B7

95

SUB

L

26S

40B8

4F

MOV

C»A

269

40B9

78

MOV

A,B

270

40 BA

9C

SBB

H

271

40BB

47

MOV

B«A

272

408C

E3

XTHL

NOW BC=REM, DE = HOLDt HL«QU0

1. TOS=DIV

273

4080

19

DAD

0

QUO = QUO ♦ HOLD

27<^

408E

E3

XTHL

NOW BCsREMt DEsHOLD. HL"DlVi

TOSxQUO

275

4nBF

C3A540

JMP

HALVEDIV

ENODO.

277

40C2

El

DIVOONE

POP

H

GET QUOTIENT TO HL

278

40C3

59

MOV

E.C

MOVE FINAL REM TO 0£

279

40 C4

50

MOV

0«B

2B0

4005

CI

POP

B

RECALL SIGN BYTE FOR RESULT

281

40C6

C36140

JMP

SIGNRCL

COMPUTE FINAL SIGN OF RESULT AND RETURN

282

a

283

»

INTERNAL

SUBROUTINE

CMPBH - COMPARE BC TO HL...

23^

»

285

40C9

79

CMPBH

MOV

A,C

236

40CA

95

SUS

L

287

ifOCB

78

MOV

AtB

288

40CC

9C

SBB

H

SIGN. ZERO NOW REFLECT (BC) - (HL)...

289

40CO

C9

RET

290

«

291

INTERNAL

SUBROUTINE

DIVBY2 - DIVIDE <HL) BY 2 (RITE SHIFT)

292

KILLS PSW. REMAINDER RETURNED IN CY.

293

»

294

40CE

AF

DIVBY2

XRA

A

CLEAR CY

295

40CF

7C

MOV

A,H

296

4000

IF

RAR

297

40D1

67

MOV

HtA

298

4002

70

MOV

A.L

299

4003

IF

RAR

300

4004

6F

MOV

L,A

301

4005

B4

ORA

H

SET ZERO FLAG IF BOTH H AND L = 0

302

4006

C9

RET

•««««*»»««»««»«««»»««*««««««««*»««««»«*«**«««««»«#»«»«**^^

» •

• SUBROUTINE DECBI«4 - CONVERT ASCII DECIMAL TO BINARY NUMBER •

305 » THIS ROUTINE CONVERTS A STRING OF ASCII CHARACTERS REPRESENTING

306 • A NUMBER TO A SIGNED 16-BIT NUMBER IN TWOS COMPLEMENT FORM.

307 • LEGAL RANGE OF CONVERTIBLE VALUES IS -32767 TO +32767.

308 • LEGAL FORM FOR STRING IS...

309 »

310 • <BLANKS><SIGN><BLANKS><OIGITS><NON-OIGIT>

311 •

312 • WHERE <BLANKS> IS 0 OR MORE BLANKS.

313 • <SIGN> IS -» OR OMITTED.

314 • <D16ITS> IS A STRING OF 1 OR MORE NUMERIC DIGITS,

315 » REPRESENTING AN INTEGER NOT EXCEEDING 32767.

316 • <NON-DIGIT> IS ANY NON-DIGIT CHARACTER (E.G., A BLANK).

317 •

318 • USAGE:

319 •

320 • ON CALL:

321 • (DE) = ADDRESS OF START-OE^ASCII STRING TO BE CONVERTED.

322 • ON RETURN TO CALLING PROGRAM...

323 (HL) = RETURNED SIGNED NUMERIC VALUE

324 » (DE) = ADDRESS OF TERMINAL CHARACTER OF STRING (<NON-DIGIT>)

325 » SIGN AND ZERO FLAGS WILL BE SET TO REFLECT VALUE IN (HL).

Listing 1 continued on page 220

216 May 1981 © BYTE Publications Inc

E

CQIVIPJTHQWICS

C.

i • EVERYTHING FOR YOUR TR8

MODEL in

tt All orders processed within 24-Hours ie 30-Day money back guarantee on all TRSDOS Softwart ★ Add $2.00 for shipping in UPS Areas •k Add $4.00 for C.O.D. or NON-UPS Areas * Add $5.00 outside U.S.A., Canada & Mexico ■k We will match any bonafide advertised price in anj/ of the Major Computer Magaxines

•»t^> k 1 lr«d«iii«li ol Tmdy Corp.

OENERAL LEDQER, ACCOUNTS RECEIVABLE, ACCOUNTS PAYABLE, PAYROLL, INVENTORY CONTROL AND INVOICINQ (Small Business Group).....an ■xtanslva buslnns

system for the serious user can be used one module at a time or as a coordinated system

$1M.W per module $1199.98 lor the complete system.*

I MASTER PAC 100 100 essential programs.....BUSINESS PERSONAL FINANCE

STATISTICS MATH QAMBLINQ GAMES includes 125 page manual and 5 diskettes

fS9.H

BUSINESS PAC 10O.....iaO essentia! business programs INVENTORY CONTROL PAY

ROLL....BOOKKEEPINQ SYSTEM STOCK CALCULATIONS CHECKBOOK MAINTENANCE ACCOUNTS RECEIVABLE ACCOUNTS PAYABLE includes 125 page manual

and nva diskettes $99.95

' INFORMATION SYSTEM (The Bottom Shelf) An In-memory Information system for small

mailing lists, inventories (i.e. books, articles, records, program reference files) Can be used

tor anything that you would use rolodex or Index card flies Up to ten user define fields

Programmable printouts for ralodex cards, mailing labels, etc Will identify all records that

contain a group of characters you've entered even if that group Is In the middle of a line Sorts

data base by anjr field $49.50*

DATA MANAGER II (The Bottom Shelf) RANDOM ACCESS Disk based DATA MANAGEMENT SYSTEM (Simiilsr to INFORMATION SYSTEM above but RANDOM ACCESS

STORAGE expands the amount of storage space available) Used to replace index cards for

medium sized mail lists, Inventories, personnel records, sales prospects, etc Uses up to four

disk drives on line Up to twenty user defined fields, programmable printouts for rolodex

cards, etc will identify all records that contain a group of characters you've entered even If

that group is in the middle of a line maintain up to 5 changeable presorted "key" files

variable length random records (the smaller the record you define, the more records yu can store) $99.95*

BUSINESS MAIL SYSTEM (The Bottom Shelf) Handles large mailing lists (up to 150.000

names) supports 3 or 4 line addresses files automatically in zip code order, alphabetical

within zip code formats for 1 to 4 across mailing labels supports quick disk location of

single or multiple names meets all Industry and postal standards numeric code fields

included for printing selected records $125.00'

ANALYSIS PAD (The Bottom Shelf) A Columnar Calculator for financial analysis, line item

budgeting, cost analysis, sales analysis and almost any financial function (and many statistical

functions) create matrixes of 29 « 39 make ail entries at one time either by row or column

add, delete, move or switch columns and rows edit any data from full screen display add,

subtract, multiply and divide one column by another and put results in designated column (up to six calculations can be made and placed in designated column) define columns as constants save calculations and formulas on disk....,iesults can be printed In a variety of report

formats $99.95*

CHECKBOOK II (The Bottom Shelf) A complete in memory checkbook balancing and

reconcllliation program five column keyboard input with S characters for check number, 16

for payee, 4 for code numerical sort routine $49.50*

CHECK REGISTER ACCOUNTING SYSTEM (The Bottom Shelf) A complete random access

checkbook system set and define up to GO accounts with as many income accounts as you

choose complete checkbook balancing and reconctlliation single entry input where

transaction can be dispersed over several accounts enables user to make a64-character note

on each transaction print out your own check after data entry prints monthly summaries of

each account with month and year-to-date totals create a suspense file to remind you of

coming expenses Reports generated included Check Register (for any month), notes to

Check Register, income/Expense Distribution Report, Statement of Selected Accounts, Bank Reconcile Statement, Suspense File and Full Account Distribution Statement $74.95*

LIBRARY 100 (The Bottom Shelf) 100 Programs on a broad range of topics Finance

Education Graphics Home Games CASSETTE VERSION $49.50

DISK VERSION $74.95

ADVENTURE (by Scott Adams) A series ol games (for ages 10-99) wander through enchanted worlds seeking treasures 1. Adventureland 2. Pirate's Adventure 3. Mission

Impossible Adventure 4. Voodoo Castle S. The Count 6. Strange Odyssey 7. (ilystery

Fun House 8. Pyramid of Doom 9. Ghost Town (#1 and tl2 recommended for the movie

adventure) Each adventure $14.95 (Jon cassette) Diskette versions sold In groups of three

at $39.95 per three programs (*1 - #3, #4 - #6, #7 - #9).

HORSE SELECTOR II (Dr. Hal Davis) New simplified version of the original Horse Selector

(for flats) The first Horse Selection System to actually calculate the estimsted offs for each

harse,.,..easy to follow ruies....,uses 4 lectors (speed rating, track variant, distance of the

present race, distance of the last race).....caiculatad estimated odds FREE DUTCHING

TABLES allows betting on 2 or more horses with a guaranteed profit $50J)0

MON-3 and MON-4 (Howe Software) Powerful utility programs enabling you to interact

directly with your TRS-80 In MACHINE UVNQUAGE The monitor comes with complete

40-page Instruction manual making it useful for both the beginner and advanced programmer....

simple commands make it easy to use functions include DISPLAY, DISASSEMBLE, tvtOVE

and COMPARE, SEARCH, MODIFY, RELOCATE, PRINT, READ and WRITE, UNLOAD, SAVE

end READ, INPUT and OUTPUT, SEND and RECEiVE.....M0N-3 $39.95 (for cassette)

MON-4 $49.95 (for disk).

(14) SMART TERMINAL (Howe Software) enables your TRS-80 to be used es a remote terminal

to a time sharing computer system $69.95

(15) FAST SORT (Howe Software) a series of machine-language subroutines to sort data from

BASIC programs data may be alphabetic (string) or numeric easily Interfaced with your

BASIC programs (no machine language knowledge Is necessary) $9.95

(16) MAILING LIST (Howe Software) maintains mailing lists of over 1000 names commands

allow adding, changing, deleting, and finding names. Sorting is done In machine language subroutine labels printed In 1, 2 or 3 columns $69.95

(17) HOME BUDGET (Howe Software) combines the maintenance of your checkbook with

analysis of your Income, expenses and monthly bills. Handles data including bills, Income, deposits, checks and debits to your checking account, and cash expenses. Computes checkbook balance, list of unpaid bills, monthly and year-to-datesummariesof Income and expenses

showing income tax deductions All output printed on video display or line printer comes

with complete Instructions manual $49.95*

(18) SMALL BUSINESS ACCOUNTING (Howe Software) Based on the DOME BOOKKEEPING

SYSTEM keeps track of all income, expenditures and payroll for a small business of up to 16

employees Income and expenditures can be entered on a daily, weekly or monthly basis

computes monthly and year to date totala manual contains complete instrucltons lor custom

izstion Cassette version $2>.95.....0lskette version $49.95

(19) REMODEL-PROLOAD (Racet Computes)., one part of a program to another

..Renumberprogram llnes.....movestatements from

$34.95

(20) QSF (Racet Computes) Lightning fsst In-memory machine language sort utility that can be

made part of your BASIC progams without any machine language knowledge Includes

several other utilities to speed up your BASIC programs no machine knowledge necessary

to use GSF In your BASIC programs $30.00

(21) D080RT (Racet Computes).....inciudes QSF (above) extends the in memory sort to sorts

on multiple disk drives $45.00*

(22) COPSYS (Racet Computes) allows the user to make copies of machines language cassettes

without any knowledge of machine language $20.00

(23) COMRPOC (Racet Computes) an auto load program for disk users allows the user to

insert a diskette into their MOD-lil and have the computer take over all loading load a

machine language program, BASIC, RUN a certain program ail without pressing a single button

allows your computer to perform 10, 20, 30 or more functions without pressing a single

button $30.00*

(24) INFINE BASIC (Racet Computes) adds a variety of machine language subroutines to your

BASIC programs (without any machine language knowledge).....fast sorts matrix operations

compress and uncompress data and more $60.00

(25) INFINITE BUSINESS (Racet Computes) an add on package to INFINITE BASIC adds a

variety of routines important to the businessman (Increase accuracy of calculations and more)

$30.00

(26) DMS (Racet Computes) lightning fast machine language sort sorts up to 4 disk drives of

information $90.00*

(27) BLINK (Racet Computes) allows you to RUN new programs without losing the variables

stored in your previous program line many programs together without losing Important

variables $30.00*

(28) KFS-80 (Racet Computes) now you can use ISAM (Index Sequential Access Files) on your

MOD-III using ISAM in your BASIC programs allows instant access of your Items in your

data files use with mail programs inventory programs etc. $100.00*

(29) MAIL LIST (Racet Computes) all routines are in machine language allowing for quick

access $75.00

• FOR DISK ONLY Circle 173 on inquiry card.

iCQnPlJTHQWlCS:

SO N. PASCACK ROAD SPRING VALLEY, NEW YORK 10977

NEW TOLL-FREE

ORDER LINE

(OUTSIDE OF N.Y. STATE)

(800) 431-2818

(914) 425-1535

HOUR ORDER LINE

EAST COAST

nMEGA Sales Co. 12 Meeting St. Cumberland, Rl 02864

1-800-556-7586

1-401-722-1027

SPBCIAL Of THB MONTH.'

INTERTEC SUPERBRAIN 64K RAM $2849

TOGETHER FOR ONLY] $5195

NEC 5510 SPINWRITER

16K ATARI 800 $759

DIABLO I $1995

Tractor option $200^

OKIDATA MICROLINE-83

$949

OKIDATA MICROLINE-80

$469

APPLE II PLUS48K

$1150

APPLE DISK w/ 3.3 DOS Controller

$545

APPLE DISK w/o Controller

$435

BASE II PRINTER

$649

HAZELTINE 1420

$799

NORTHSTAR HORIZON II 32K QD

$2975

ATARI 400 8K

$399

ATARI 400 16K

$499

• NO SURCHARGE FOR CREDIT CARDS

• WE ACCEPT C.O.D.'S

• ALL EQUIPMENT FACTORY FRESH W/MANUFACTURER'S WARRANTY

• STOCK SHIPMENTS USUALLY SAME DAY OR NEXT DAY

• NO HIDDEN CHARGES

WE LIVE BY OUR PUBLISHED PRICES

rilVIEGA SALES COMPANY

218 BYTE May 1«B1

WEST COAST

OMEGA Sales Co. 3353 Old Conejo Rd. #102 Newbury Park, CA 91320

1-800-235-3581

1-805-499-3678

RADIO SHACK 16K Level II Model 3

RADIO SHACK 64K Model 2

ANADEX DP-9500

TELEVIDEO 912C

TELEVIDEO 920C

TELEVIDEO 950

ATARI 825 PRINTER

ATARI 850 INTERFACE

ATARI 810 DISK

(Call for price list of ATARI Software)

$875 $3449 $1249 $669 $729 $1049 $729 $169 $449

C-ITOF

STARWRITER 25~

$1595

EPSON MX-80 PRINTER

INTERFACES: IEEE $55, TRS'SO $35. APPLE INTERFACE + CABLE $90,

Rs.232$7o Call for price

NEC MONITOR $219

CALL TOLL FREE

EAST COAST / WEST COAST

1-800-556-7586 1-800-235-3581

MEGA SALES COMPANY

BYTEMayim 2X9

Listing 1 continued:

326

CY CLEARED. A REGISTER CLOBBERED. B» C RESTORED.

327

«

328

•

NOTES

ON METHOD... B

REG USED TO HOLD 3 FLAGS...

329

«

BIT 7

="-" FLAG = MINUS SIGN ENCOUNTERED

330

•

BIT 6

s "SE" FLAG = SIGN ENCOUNTERED

331

»

BIT 0

= "OE" = DIGIT

ENCOUNTERED.

332

«

333

4007

C5

DEC8IN

PUSH

B

33*

4008

0600

MVI

8,0

INITIALIZE FLAGS -,DE,SE

335

40DA

210000

LXI

H,0

INITIALIZE RESULT

336

40D0

lA

AKLOOP

LOAX

0

FETCH NEXT ASCII CHARACTER

337

40DE

0630

SUI

48

CONVERT CHAR TO BCD DIGIT IF POSSIBLE

33B

4OE0

4F

MOV

C,A

SAVE {CHARACTER-48) IN C

339

40E1

FAFF40

JM

NOTDIGIT

IS IT A DIGIT 0 THRU 9...

3«>0

4nE4

FEOA

CP I

10

3<»1

F2FF

JP

NOTOIGIT

3*2

40E9

05

PUSH

0

...IF SO, SAVE BUFFER POINTER

3<*3

40EA

llOAOO

LXI

0,10

...MULTIPLY PARTIAL RESULT BY 10...

34*

40ED

C03840

CALL

EMULT

...(ALSO CHECKING FOR OVERFLOW)...

345

40F0

1600

MVI

0,0

...ANO AOD IN VALUE OF DIGIT...

346

40F2

59

MOV

E,C

347

40F3

CD0040

CALL

EAOD

(HL) = (HL)*10 ♦ DIGIT

348

40F6

01

POP

0

RECALL BUFFER POINTER

349

40F7

13

INX

0

BUMP BUFFER POINTER

350

40F8

3E01

MVI

A,l

...SET "DIGIT ENCOUNTERED (DE) FLAG...

351

40FA

BO

OR A

B

352

40FS

47

MOV

BtA '

353

40FC

C3DD40

JMP

AKLOOP

...AND WERE READY FOR NEXT CHARACTER

354

»

355

•

COME 1

HERE FOR ANY CHARACTER EXCEPT 0.1t...9

356

«

357

40FF

79

NOT0I6IT

MOV

A,C

RECALL (CHAR-48)

358

4100

FEFO

CPI

-16

IS IT A BLANK. SET ZERO FLAG IF SO.

359

4102

78

MOV

A,B

RECALL FLAGS

360

4103

OF

RRC

TEST "DIGIT ENCOUNTERED" FLAG IN CY

361

4104

0A6140

JC

SIGNRCL

IF DIGITS ENCOUNTERED PRIOR, WERE DONE

362

4107

C20E41

JNZ

TRYSIGN

...ELSE, IF NOT BLANK TRY ♦ OR

363

410A

13

INX

D

...ELSE IGNORE LEADING BLANK,

364

410B

C300*0

JMP

AKLOOP

AND PROCEED WITH NEXT CHARACTER

365

410E

78

TRYSIGN

MOV

A«B

TEST »SE" FLAG IN CY

366

41 OF

07

RLC

367

4110

07

RLC

368

4111

OCOOOO

CC

CONVERR

369

4114

79

MOV

A,C

ELSE RECALL (CHAR-48)

370

4115

FEFO

CPI

-3

IS IT "-"...

371

4117

C2

JNZ

TRYPLUS

...IF NOT TRY FOR "♦" SIGN...

372

41 lA

3EC0

MVI

AfOCOH

...IF IT IS "-", SET SE AND - FLAG

373

4I1C

BO

ORA

B

374

411D

47

MOV

B,A

375

411E

13

INX

0

BUMP BUFFER POINTER

376

411F

C30040

JMP

AKLOOP

ANO PROCEED WITH NEXT CHARACTER

377

4122

FEF8

tryplus

CPI

-5

IS IT "♦" CHARACTER...

378

4124

C40000

CNZ

CONVERR

IF NOT ITS AN ERROR

379

4127

3E40

MVI

A,40H

IF IT IS "♦», SET "SE" FLAG

380

4129

BO

ORA

B

3B1

412A

47

MOV

B.A

382

412B

13

INX

D

BUMP BUFFER POINTER

383

4I2C

C3DD40

JMP

AKLOOP

AND PROCEED WITH NEXT CHARACTER

384

«

••••••««»»•»•«»•••«««»««»»««»*•••••••••••••••••••••••»•»«»«•«•«»•*»«»«»««»««««««

• «

• SUBROUTINE BINOEC - CONVERT BINARY NUMBER TO DECIMAL ASCII STRING •

• • «»•»••»»*««»»«»«»«»»«»«»•«»•««««•*•«••*«••«•••*««•••««*««««•••••««»«»•••••«««•••

387 388 389 390 391 39? 393 394 395 396 397 398 399 400 401

412F 4130 4131

C5 E5

010000

8INDFC

THIS ROUTINE GENERATES A STRING OF ASCII CHARACTERS REPRESENTING A SIGNED DECIMAL INTEGER. THE STRING IS GENERATED LEFT-JUSTIFIED, WITH LEADING ZEROS SUPPRESSED. THE STRING WILL OCCUPY FROM 1 TO 6 CHARACTERS DEPENDING ON THE SIGN AND MAGNITUDE OF THE NUMBER DESIRED. ON CALL: (HL) = SIGNED BINARY NUMBER TO BE CONVERTED. (DE) = ADDRESS OF FIRST CHARACTER OF BUFFER WHERE STRING IS TO BE GENERATED.

ON return: (DE) = ADDRESS OF NEXT BYTE AFTER THE STRING WHICH WAS GENERATED. (A) = NUMBER OF CHARACTERS GENERATED. B, C» H» L RESTORED.

PUSH PUSH LXI

B H

B,0

SAVE HL

B=MINUS FLAG, C= DIGIT COUNTER

Listing 1 continued on page 222

220 May 1981 © BYTE Publicatioiu Inc

Reliable/low cost single board design w/Z80 CPU.

Supports 1 to 4 singie density floppy disks.

External S100 Bus available for extended adaptability (12 slots).

Four serial RS232 ports (parallel option available).

Iilandom Access Memory: 64K RAM standard.

Data Communications: Integrated modem or any RS232 compatible external modem.

The Versatile Computer Company

Sierra National Corporation 5037 Ruffner Street San Diego, CA 92111 Tel: 714-277-4810 TWX: 910-335-1532

Data Storage Power with 0.5 to 96 Megabytes available. The SI 00 Bus and SMD disk controller access a variety of hard disk systems:

BASF 8. 24, 40 Megabytes

(fixed Winchester system) AMPEX 32, 64, 96 Megabytes

(fixed Winchester -I- removable

cartridge) CDC 32, 64, 96 Megabytes

(fixed Winchester + removable

cartridge)

Multiprocessing: Multiple computer boards can be mounted within the System 4000 chassis and each can support a separate user station with its own display terminal and printer. The terminal network is controlled by a master CPU and each slave has the computational speed and memory size necessary to execute sophisticated programs without burdening the other user stations.

SIERRA'S

PROFESSIONAL APPLICATION

SOFTWARE

General Ledger

Accounts Receivable w/invoicing

Inventory

Accounts Payable

Payroll

PLUS

Many specific market adaptations:

Wordprocessing

Medical/Dental

Property Management

Insurance

Contractor

Accountants

Manufacturing, etc.

Spanish! versions available.

OPERATING SYSTEMS

CP/M MP/M CP/NET

LANGUAGES

Fortran

Basic

Cobol

Pascal

ALSO

Sierra provides dealers or end user:

• TIME-SHARING

• TRAINING

• SOFTWARE DEVELOPMENT

as part of our complete customer support

service.

Attractive dealer package offered. Please inquire.

Circle 367 on Inquiry card.

BYTE May 1981 221

Listing 1 continued:

402

4134

E5

PUSH

H

403

4135

29

DAD

H

PUSH SIGN INTO CY

404

41 36

fil

POP

H

RECALL UN-SHIFTED NO.

405

41 37

024241

JNC

DIVIOK

FALL THRU FOR - NUMBER

406

41 3A

3E2D

MVI

A, 45

ASCII MINUS SIGN

407

41 3C

12

5TAA

0

INTO BUFFER

408

41 30

04

INR

B

SET MINUS FLAG

409

41 3E

13

INX

0

AND BUFFER POIMTER

410

413F

CD3040

CALL

C0MP2

ABSOLUTE VALUE OF NUMBER

411

4142

E8

DIVloK

XCH6

N TO DEi BUFF ADDR TO HL

412

4143

228441

SHLD

BUFADR

SAVE BUFFER ADDRESS

413

4146

E8

XCHG

414

41 47

111027

LXI

DtlOOOO

415

41 4A

C06E'fl

CALL

CNVTIOIG

FIND FIRST DECIMAL DIGIT

416

41 40

11E803

LXI

0,1000

417

4150

C06E41

CALL

CNVTlDIG

SECOND DEC DIGIT...

418

4153

116400

LXI

0,100

419

4156

C06E41

CALL

CNVTIOIG

THIRD...

420

4159

llOAOO

LXI

0,10

421

415C

CD6E41

CALL

CNVTlDIG

4TH

422

415F

70

MOV

A»L

LAST DIGIT IS FINAL REMAINDER

423

4160

ADI

48

CONVERT TO ASCII CHAR

424

4162

OC

INR

C

425

4163

2A8441

LHLD

BUFADR

RECALL BUFFER "OINTER

426

4166

E8

XCHG

427

4167

12

STAX

0

INSTALL LAST CHARACTER INTO BUFFER

428

41 68

79

MOV

A,C

RETURN CHARACTER COUNT IN A REG

429

4169

80

ADO

B

...AMD ADD 1 FOR MINUS SIGN IF MINUS

430

416A

13

INX

0

POINT TO NEXT DIGIT IN BUFFER

431

416B

Fl

POP

H

FINAL RESTORE FOR HL

432

416C

CI

POP

B

RECALL B

433

4160

C9

RET

434

416E

C07F40

CNVTlDIG

CALL

EOIVHOO

DIVIDE REMAINDER BY 10**N

435

4171

EB

XCHG

NEW REM TO HL

436

4172

78

MOV

A«E

DIGIT TO A

437

4173

Rl

ORA

C

IF NO NON-ZERO DIGITS SO FAR...

438

4174

C8

RZ

...AND THIS = 0, THEN SUPPRESS LEADING

439

41 75

78

MOV

A,E

ELSE, RECALL DIGIT

440

4176

C630

ADI

48

CONVERT DIGIT TO CHAR

441

4178

DC

INR

C

UPDATE CHAR COUNTER

442

4179

EB

XCHG

443

417A

2A8441

LHLD

BUFADR

BUFFER ADDRESS LOAD

444

4170

77

MOV

M.A

STORE CHAR IN BUFFER

445

417E

23

INX

H

NEXT CHAR

446

417F

228441

SHLO

BUFADR

SAVE BUFFER POINTER

447

4182

EB

XCHG

448

41S3

C9

RET

« •

FOLLOWING

MUST BE

IN READ/WRITE MEMORY...

450

4184

BUFADR DS

2

451

4186

END

-SYMBOL

-VALUE

-R

-DEFINED

-REFERENCED

AKLOOP

4000

•A

336

353

364

8INDEC

412F

• A

399

29

BUFADR

4184

»A

450

412

425

CHIN

0000

7

13

CHOUT

0000

8

27

36

CMPBH

40C9

•A

285

255

264

CNVTIOIG

416E

»A

434

415

417

C0MP2

4030

•A

161

141

156

CONVERR

0000

102

368

378

DBLDIV

409A

«A

252

257

DECBIN

40D7

«A

333

20

23

DIVBY2

40CE

«A

294

260

263

DIVDONE

40C2

»A

277

261

DIVIOK

4142

»A

411

405

EAOD

4000

»A

110

142

347

ECHS

4020

»A

151

•UNUSED

ECHSGO

402A

»A

156

153

EDIVMOD

407F

•A

234

434

EMULT

4038

«A

175

25

344

ESIGN

40 OE

»A

125

114

157

TEMPORARY STORAGE FOR POINTER

376 443

419 205

383 446

421 217

224

410

207

Listing 1 continued on page 224

222 May 1981 © BYTE PubUcaUons Inc

MEMORkfX

SUPERB QUALITY AT UNBEATABLE PRICES.

THATS MEMOREX DISCS FROM PACIFIC EXCHANGES

on inquiry card.

BYTE May 1981 223

Listing 1 continued:

ESUB

4016

*A

139

•UNUSED

HALVtDIV

40 A5

» A *A

259

COD

37C

HLSMALL

4048

1 oc

1 b n

T kl Q 1 IP

« A

1 ? 1 c

1 Q

UnUT TAD MUNI 1UK

n n n n u u u u

o

nfU 1 UiOl 1

fur r

« A

J3 f

J J7

JH I

UU1 our

CO

UVtK"LUW

Annn u u u u

1 U 1

lift

155

OGI TCTRKl

HU 0~

■0-A

1 77 Iff

239

4056

1 on

SISNRCL

4061

♦A

200

281

361

TEST

3000

»A

12

•UNUSED

TESTl

3003

»A

13

18

TEST2

3010

*A

19

16

1 C 3 1 J

-H'A

33

38

TRYPLUS

4122

«A

377

371

TRYSIGN

410E

»A

365

362

XMLOOP

404C

»A

187

198

-COMMON

RLOCK^

-L

ABSOL

oiDr

THE FORMULA™ represents a new concept in report generation. It tal<es information %\ nnanagement one step fur

-^"CLl^J^^ ^ |V ther into the future. THE

1 0*5**^ lif\V**^ FORMULA™ now makes it ^^[^V%.V** ^ r-a possible to visually describe

^yV* 'tW?'^'^^ "^(jl^^ the format of desired reports by

^ ^^C3 ^^-^^T IT^ using a unique full screen edi

w-^^ ^^VxJ^ ^" typss of reports (including invoices,

financial statements, legal forms, letters, ^^V^ ^^^^ etc.) can be defined interactively on a ter

^j^J^^ mihal simply by typing the format on the

screen. It is programmed for multiple file access, algorithmic calculations and conditional printing. Incorporating DMA's data manager, The Configurable Business Systemr THE FORMULA™ provides a flexible framework you can easily adapt to your own individual needs.

THE FORMULA™ runs on any 8080 or Z80 computer with CP/M*, 48K RAM, 250K total disk storage, and a CRT (min. 16x64).

Complete System $595. Manual only $40. DMA • WE SPEAK YOUR LANGUAGE

Dynamic Microprocessor Associates • 545 Fifth Avenue, New Yorl<, New Yorl< 10017 • (212) 687-7115 We'ship prepaid and COD orders. Shipping and handling charges extra. Master Charge and Visa accepted. *CP/M Is a trademark of Digital Research.

224 May 1981 © BYTE PublicaUons Inc

Circle 134 on Inquiry card.

AMERICA'S COMPETITIVE EDGE^

Westinghouse addresses the vital role of technology in industi^

Technology is the key to the world marketplace.

If we want to maintain America's competitive edge, we must make better use of present technologies, and encourage new ones.

Most of the firms and countries which have achieved conspicuous success in this world have done so because they possessed some special advantage. They had an edge over their competitors. In recent decades, America's competitive edge has been its technology. Our ability to originate and apply innovative scientific and engineering ideas earned us a commanding lead in the world marketplace.

Things have changed

Unfortunately, that lead has dwindled. America's share of the world's manufactured goods market has eroded over the past 20 years, lost to foreign manufacturers. Not only have they captured part of what had been our share of the world market, but they are now successfully penetrating our own domestic markets.

What happened?

A look at a few statistics helps reveal some of the reasons for our reversals. Take patents. The number of domestic patent applications by Americans has been flat for several years. In contrast, the number of those filed here by foreign countries has been rising every year In 1978, almost 37 percent of the patents granted went to foreign applicants. Or take the percentage of our Gross National Product going into industrial R&D. Over the past two decades, it has dropped precipitously What is needed

Fortunately today Westinghouse and other corporations already have technologies which can help America maintain its technological leadership. And these same corporations are hard at work on tech

nologies which can expand America's leadership. The problem lies in implementing those technologies. Because, while the development of new technologies costs a large amount of money, turning them into commercial realities requires far more. A national commitment

Something else is needed: a united effort by industry, labor and government. Obviously, management should make a greater R&D effort to refine today's technologies, and develop new ones for tomorrow. Employes must realize that their cooperation is vital if America is to remain the most productive nation in the world. And our elected officials need to reestablish a sound economic foundation, because that is basic to all social progress. In particular, tax laws and monetary policy must be structured to allow industry to accumulate capital needed to apply available technologies, and invest in the development of still more advanced ones. The Westinghouse role

At Westinghouse, we believe technology is vital to our nation, our customers, and our own progress. We're supporting that belief by ambitious R&D programs, by building and modernizing existing facilities, and by introducing innovative methods to improve both our own quality and productivity and that of our customers. Today's proven Westinghouse technologies are focused on key areas such as productivity, services, energy, and America's national security These existing technologies, together with the ones we are developing for the future, represent our efforts to help maintain this nation's competitive edge. On the following pages are some examples.

6 1

Outlavs as DsrcGnt 'HI

of Gross National Product

2^7%

1960

1,58%

1979

Source; National Science Foundation

Percent share manufactured goods from 15 major countries excluding exports to U.S.

25.3% 1960

17.4% 1979

Number of applications filed: Inventions

100,916 1978

79,596 1960

Source: U.S. Department of Commerce

I

WESTINGHOUSE TECHNOLOGY APPLIED TO

ENERGY

Someday, Westinghouse technology will provide economical electricity from tlie sun, and clean gas from coal.

The fact that silicon photovoltaic cells can turn sunlight into electric current has been known for some tinne. The problem is the high cost involved. Westinghouse has invented a new dendritic web process that significantly reduces the cost of producing such cells. As a result, theU.S. Departmentof Energy's economic cost target now appears achievable. Westinghouse is working with the two largest electrical utilities in California to provide demonstration photovoltaic modules this year.

Advanced energy technologies

Westinghouse is involved in the advanced energy technologies that may play a role in this nation's energy future. For example, on the horizon are promising technologies like iron-nickel, and iron-air high power batteries. Also showing promise are fuel cells that chemically produce electricity But until solar and other energy technologies become a reality this nation will depend upon coal and nuclear power for its electricity. Westinghouse is focusing much of its effort on these two areas.

Clean gas from coal

Westinghouse has pioneered in coal gasification technology. Over the last decade we have developed a process to turn coal into a clean gas for power generation, and for industrial or synthetic natural gas applications. The process has the advantage that it can use virtually any type of coal, soft coal or hard coal. The environmental impact is minimal, regardless of the coal's moisture, sulphur, or ash content. With continued technical progress, Westinghouse coal gasification systems can be in commercial operation by the mid-1980's. Nuclear technology Nuclear power remains an economical and safe way of producing electricity Westinghouse leads in the application of nuclear technology to generate electricity. And we are developing an advanced nuclear plant able to make more fuel than it uses.

WESTINGHOUSE TECHNOLOGY APPLIED TO

SECURITY

Today, Westinghouse Airborne Radar is one of our first lines of defense around the world.

It's called AWACS, an airborne warning and control system which provides long-range surveillance in an area at least 20 times greater than any surface-based system. It's already in use by our Air Force, and has been adopted by NATO. Just one AWACS radar mounted on a military version of the Boeing 707 flying at 30,000 feet can provide early warning of enemy attacks in an airspace of more than three million cubic miles. The information it helps give to military commanders multiplies the effectiveness of our air defense systems. New safety for pilots Another Westinghouse system protects aircraft crews from fast-closing missiles and enemy aircraft. It's called ourTail Warning Radarand it

provides the pilot with accurate warnings to take evasive maneuvers. It also automatically triggers appropriate countermeasures. It's able to do all this in a split second, and with a phenomenally low false alarm rate.

Radar, of course, has many applications in commercial aviation, and its importance grows as the skies become more crowded. Thirty-six Westinghouse Air Traffic Control surveillance radars are now serving

the FAA, the Switzerland Federal Air Office, and the Canadian Department of National Defense. The FAA uses the radars in some of the nation's most heavily traveled areas. So, nearly all domestic commercial flights come under the surveillance of a Westinghouse radar at some point during their flight.

WESTINGHOUSE TECHNOLOGY APPLIED TD

PRODUCTIVITY

How Westinghouse product can increase industrial

How to increase output per hour...

How to eliminate waste...

How to cut energy costs...

Westinghouse has developed products

and systems able to provide

a wide variety of industries

with effective answers.

Here are several of special interest.

The Westinghouse Numa-Logic® Control System

The Westinghouse Numa-Logic solid-state programmable controller uses microprocessor technology to provide more reliable operation for electrical control applications. It can economically replace as few as eight relays. It also has the capability to control the hundreds of sequences required by sophisticated, automated processes. The Westinghouse Numa-Logic system is being used in the machine tool, materials handling, textile, paper, steel-making and other industries to reduce downtime, give quick start-ups, and increase operationa efficiency.

Factory computer systems

Also making major contributions to increased productivity are Westinghouse factory computer systems. They are capable of operating as many as 100 different machine tools simultaneously They can also provide real time status and performance monitoring at four levels: maintenance, shop supervisor, middle and upper management. In application after application, downtime has been sharply reduced, and actual machine time has been increased up to 55 percent.

Power electronics

Solid-state static VAR generators are a key solution for utility and industrial system line problems because they provide system stability and improve power flow capability. Planning studies at a major utility concluded that 10 transmission lines with static VAR generators could deliver the power ordinarily requiring 16 lines. When it comes to industrial applications such as steel-making, VAR generators can improve the efficiency of power usage by improving the power factor and providing faster arc furnace melt times. One steel producer's productivity increased sufficiently to pay back the nearly $2 million cost of the static VAR generator in 15 months.

and service technologies productivity today.

Applied Plasma Systems

Because of the skyrocketing costs of fossil fuels used to supply process heat or chemical reactions, many firms are searching for alternatives. The Westinghouse Applied Plasma Systems can efficiently fire high temperature industrial processes, and serve as a central heating device for a myriad of applications such as chemical processes, metals treating, and combustion replacement. This technology is already providing an efficient answer for blast furnaces and direct reduction iron-making processes. It uses a high temperature gas stream to transmit heat. Studies on the upgrading of existing blast furnace facilities demonstrate up to an 80 percent increase in the capacity of the facilities through the application of AppI ied Plasma Systems.

How to minimize downtime... As machines grow more complex, keeping them running tal<es specialists. To help you maximize productivity, Westinghouse can provide the same technological expertise in services as it does in products.

A remarkable worldwide service network

Because Westinghouse engineers, tests, and builds complex products and systems, we have the special skills, trained personnel, and necessary tools to maintain such equipment best; or to repair it in the least amount of time. Available to help you with either maintenance or repair are hundreds of trained Westinghouse field service engineers and specialist mechanics who use the most sophisticated on-site testing and repair equipment. And backing them up is a vast network of repair facilities.

Whether Westinghouse built it or not, we can service and repair almost anything from escalators and elevators, to steam turbines and nuclear power plants. Westinghouse can do an operation analysis and recommend an upgrading program, we can train your operators and service personnel, or we can do continuous monitoring of various operations. Whatever is needed.

Experience has taught us that a regularly planned and scheduled maintenance program greatly increases uptime and saves money. Westinghouse is equipped to provide programmed maintenance on a plant-wide basis. During scheduled shutdowns, a crew of Westinghouse field engineers and technicians can move in to do a complete analysis and topto-bottom overhaul of your entire facilities.

Technology is America's competitive edp.

• To retain tliat competitive edge, we must malce better use of the technoiogies we aiready have, and activeiy encourage the deveiopment of new ones.

• Westinghouse beiieves technology is vital to our nation, our customers, and our own growth.

• Westinghouse has technologies that increase manufacturing productivity, help meet our energy needs, and contribute to our national security.

Six Gateway Center-Dept. 10 Pittsburgh, PA 15222

^Westinghouse

A powerful part of your life.

Listing 2: Test program for the arithmetic subroutines. This program receives two numbers from the keyboard and displays their product. Note that the user must supply entry points to character input and output routines and to the system monitor (or any other program to be jumped to when this program ends).

• TEST PROGRAM DISPLAYS PRODUCT OF 2 NUMBERS ENTERED FROM KEYBOARD

5 6

# *

NOTES YOU MUST

7

CHIN

EQU

0

SUBROUTINE TO GET KEYBOARD CHAR. IN A REG.

a

CHOUT

EQU

0

SUBROUTINE TO DISPLAY (A) AS ASCII CHAR.

9 10

MONITOR

EQU

0

ENTRY TO SYSTEM WHEN PROGRAM DONE

11

ORG

3000H

12

3000

213B30

TEST

LXI

HflNBUF

INPUT SUFFER ADDRESS TO HL

13

3003

COOOOO

TEST!

CALL

CHIN

GET AN ASCII CHARACTER IN A REGISTER

Ik

3006

77

MOV

M,A

STORE CHARACTER INTO BUFFER

15

3007

FEOD

CP I

13

AND IF ITS A CARRIAGE RETURN

16

3009

CA1030

JZ

TEST2

THEN BRANCH

17

300C

23

INX

H

ELSE* ADVANCE TO NEXT BYTE OF BUFFER

IB

3000

C30330

JMP

TESTl

...AND CONTINUE

19

3010

113B30

TEST2

LXI

OtINBUF

RECALL INPUT BUFFER STARTING ADDRESS

20

3013

CDD740

CALL

OECBIN

CONVERT ASCII DECIMAL TO BINARY NUMBER

21

3016

E5

PUSH

H

SAVE NUMBER

22

3017

13

INX

0

ADDRESS OF START OF SECOND NUMBER STRING

23

3018

CUU f hO

CALL

CONVtKI 5LC0ND NUnBtK TO OINART IN ML

24

301B

Dl

POP

0

RECALL FIRST NUMBER

25

301C

€03840

CALL

EMULT

FIND PRODUCT IN HL

26

301F

3E0A

MVI

AtlO

ASCII LINE FEED

27

3021

COOOOO

CALL

CHOUT

START ANSWER ON NEW LINE

28

3024

114F

LXI

D«OUTBUF

OUTPUT BUFFER STARTING ADDRESS

29

3027

C02F41

CALL

BINOEC

CONVERT ANSWER TO ASCII STRING

30

302A

AF

XRA

A

31

302B

12

STAX

D

MARK ENO-OF-STRING WITH 0-8YTE

32

302C

214F30

LXI

H,OUTBUF

RECALL START OF BUFFER

33

302F

AF

TEST3

XRA

A

34

3030

86

ADO

M

FETCH NEXT CHARACTER

35

3031

CAOOOO

JZ

MONITOR

IF ITS 0-BYTE TERMINATORf QUIT

36

3034

COOOOO

CALL

CHOUT

ELSEf DISPLAY BYTE

37

3037

23

INX

H

ADVANCE BUFFER POINTER

38

303B

C32F30

JMP

TEST3

40

303B

INBUF

OS

20

INPUT BUFFER FOR 2 NUMBERS

M

304F

OUTBUF

OS

10

OUTPUT BUFFER FOR RESULT

Two's Complement of Binary Numbers

Two's complement is a method of representing negative numbers in binary radix. It is only one of several methods of negative number representation, but it has the advantage of eliminating subtraction as a separate operation; subtraction can be performed by taking the two's complement of the subtrahend and adding it to the minuend.

The two's complement of a number is found by complementing every bit in the number (changing Is to Os and vice versa) and adding 1 to the resulting value. For

Jsttake

the two's complement of the number 4 stored as an S'-hit vahii:

4 in binary is: 00000100 complementing each bit:

union

adding 1: 1

—4 in two's complement:

11111100

(By the way, the numeral 11111011 is called the one's complement of 4.)

To show that subtraction can be performed using straight binary addition with two's complement, take the example of subtracting 4 frorr\,7:

7 in binary is: 00000111 two's complement

of4: iinnoo

adding, we get: 100000011

The carry, 1, is thrown away, and the result, 00000011, is decimal 3 in binary.

In two's complement, negative numbers always have a leftmost bit of 1; on the other hand, nonnegative numbers have a leftmost bit of 0. However, the absolute value of a negative number cannot be found by simply evaluating the lower bits; as before, you must complement the number and add 1. .

May 1981 © BYTE PubUcatioiu Inc 225

These routines run an order of magnitude faster tiian fuii fioating-point routines.

Text continued from page 204:

treat values outside the range of

-32,768 to +32,767 as an overflow

condition.

When an overflow is detected, a call is made to a subroutine called OVERROW, which is not provided because you will want to implement it

in a manner appropriate to your system. A simple error-processing routine would display an error message and jump to the system monitor. If desired, a more sophisticated error-processing routine could continue processing, because the top of the stack contains the return address to the routine where the overflow was detected. Similarly, you must provide an entry point called CONVERR, which will be called in the event of a string-numeric conversion error.

The string-numeric conversion routine, DECBIN, will convert any legitimate numeric decimal represen

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tation, including those with leading blanks or blanks between the sign and the leading digit. It will reject errors including two signs or an illegal character. Any noimumeric character after the start of the number terminates the conversion, facilitating parsing of free-format data entries. This is illustrated by the sample test program of listing 2, which accepts two numbers oh one line and prints their product on the next line. ■

The Largest and Smallest Numbers in Two's Complement Notation

Another property of two's complement numbers is that the absolute value of the largest positive number that can be represented is 1 less than the absolute value of the smallest negative number that can be represented. As an example, look at all the possible 3-bit two's complement numbers:

0 is 000; complementing and adding 1 gives 000 (or —0)

1 is 001; complementing and adding 1 gives 111 (or —1)

2 is 010; complementing and adding 1 gives 110 (or —2)

3 is Oil; complementing and adding 1 gives 101 (or —3) —1 is 111; complementing and adding 1 gives 001 (or 1) —2 is 110; complementing and adding 1 gives 010 (or 2) —3 is 101; complementing and adding 1 gives Oil (or 3)

But we have one number left over, 100. Inasmuch as the most significant bit is 1, it must be negative. To find its absolute value, take its two's complement:

the number is: complement it: addl:

100 Oil 1

its two's complement is: which is binary for 4

100

Therefore, 100 in two's complement notation must be —4. But notice that, given three bits for the binary representation of signed numbers, there is no way to represent positive 4 in two's complement notation. The largest positive number that can be represented is

226 May 1981 © BYTE Publicattons Jnc

Circle 232 on Inquiry card.

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BYTE May 1981 227

Technical Forum

Print Your Own Bar Codes

UPC Bar Codes PAPERBYTE® Bar

With the Codes With Integral

Centronics 737 Data Systems Printers

John Anderson, 149 Cliffside Dr, Wilnungton NC 28403

Hewlett-Packard's introduction of a less-than-$100 bar-code reader will certainly increase interest in bar codes as a viable means of transporting program listings through the printed media. But reading bar codes is not enough. To maximize their usefulness, we must be able to generate them as well: only then will creative applications begin to emerge. There must be numerous instances where keyboard input to small-business data-processing systems can be replaced with bar-code input.

My interest in bar codes arose from a need for simple data entry in an educational application. The problem required easy generation as well as easy reading of bar codes. To generate bar code, you must be able to produce vertical lines and spaces of equal (or approximately equal) width. This can, of course, be done with a plotter or a high-resolution graphics printer. Or, it can be done with a low-cost, dot-matrix, proportional-spacing printer, such as the Centronics 737.

I had a Centronics 737, so I began to experiment with producing bar codes, and found that the printer can be used quite effectively. The Centronics 737 produces a high-density dot-matrix print in the proportional-spacing mode. With the concatenation symbol (|) as the basic vertical bar, the printer can be directed to backspace dot by dot, allowing the compression of vertical bars into a solid bar of variable width.

Text continued on page 276

Dr G Louis, OB/GYN Dept, St Michael's Hospital, 30 Bond St, Toronto MSB 1W8 Canada

The advent of Hewlett-Packard's low-cost bar-code reader, HEDS-3000, makes it possible to consider software distribution in machine-readable form via the printed page. The bar-code reader (described in Carl Helmers' editorial, "Bar Codes, Revisited...," April 1980 BYTE, page 6) can be interfaced to a computer for slightly more than $100.

This article will describe a program that uses the graphics plotting option of an Integral Data IP-225 (or lDS-440) printer to produce bar code. (The IP-225 sells for about $1000.) The format is the PAPERBYTE® format, described in Ken Budnick's book, Bar-Code Loader (Peterborough NH: BYTE Books, 1977).

In graphics mode, the Integral Data printers allow column by column control of the image printed. Each column is 7 dots high, and each dot is controlled by the corresponding bit in the byte of data sent. For example, if you send a question mark (hexadecimal 3F) to the printer while in graphics mode, a vertical bar of 6 dots is printed. If you send a NUL (0), the printer leaves a blank that is 1 dot-width across. This takes care of 0 bits and spaces. One bits (double-width bars) are simply printed as two question marks side by side. The bar-code loader program by Ken Budnick has software filtering to correct dropouts (white spots on the bars) and blotches (black dots in the spaces), and it also proves adequate to deal

Text continued on page 230

Editor's Note: When we put the Hewlett-Packard HEDS-3000 bar-code wand on the cover of the Apt i/ JOSO BYTE, we believed that the only major obstacle to the widespread use of bar codes—lack of a reliable wand at an affordable price^had been eliminated. You couldn't make your own bar codes (we thought), but you could read them. In the January 1981 BYTE, we published an article that showed how to make HP-41C bar codes on an expensive Diablo 1650 printer (see "Generating Bar Codes in the Hewlett-Packard Format," by Thomas McNeal, January 1981 BYTE, page 148). But few people have such an expensive printer, and (we thought) most people still couldn't make their own bar codes.

We were wrong. The two articles above show two different formats of bar codes produced on two different dot-matrix printers. All of the work is done in the software; the hardware only has to generate a thin vertical bar and place it anywhere on a line. With the proper bar-code reading software, even bar codes made with dot-matrix printers can be consistently and reliably read....CW ^ ^

. i-ifr-- ^^-n ■mt''?-mt^

228 May 1981 © BYTE PublicaHons Inc

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BYTE May 1981 229

Technical Forum

Text continued from column 2, page 228:

with the tiny white spaces left between the dots in the double-width bars. The only restriction is that the printer ribbon must be in good condition; otherwise, the contrast between bar and space will not be sufficient for a reliable wand reading.

The program in listing 1 prints bar code from data in memory with start and stop addresses specified by the user. Tiny Pascal as described by K-M Chung and H Yuen (see reference 2) and implemented by me in 8080

assembly language (see reference 4) was used for this routine. Those who are unfamiliar with Pascal should have little difficulty following the algorithm: readability is one of the most important advantages of Pascal. Two minor points may give some trouble to BASIC programmers: percent signs (%) associated with numbers or variables indicate that the number or variable is expressed in hexadecimal, and the CASE X OF... statement is used to choose from among options to be executed depending on the value of X. However, interested readers

Figure 1: Bar-code representation of part of listing 1, made on an Integral Data Systems IP-225.

BAR-CODE PRINTER ~ SOURCE LIST — 800624

0000 l!ll»ll!lilttiltt!IIHIiaitllltlliitliltllUlllllHtllllHilltllltitlilliil»iltlllUtttllllli

0015 ittltlltlt|{!llil!l!!lll!l!itl!llilitilll{llilll!litliillillll!l!l!l!lliiri!lllllillll!!^il!;!!ll!n^

002? ltlltlltllUi»lltt»UIUIItilllillttlttiit!ttUtillltt!!iiaitltillllitlit!ttlltitllll»lltHttllliUI!tU

003E itilllittUliUiijltllillttllitlMlHilillllHItiltiUillH^

Listing 1: Tiny Pascal source listing for a program that will generate printed hat codes from data in memory. Translation into BASIC or assembly language should prove fairly simple, even if the user is unfamiliar with Pascal.

OOIO J *«« BAR-CODE PRINTER PROGRAM

(102(1 FDR INTEGRAL DATA lP-225 ( 440 ) WITH GRAPHICS

0030 BY DR. G. LOUIS

0040 OB/GYN DEPT.. ST, MICHAEL'S HOSPITAL

0050 30 BOND STREETt TORONTOi CANADA MSB lUS

0060 8005011 LAST MODIFIED 800^24

0070 3

0080 CONST MAXBAR=400 3 MAX UNIT WIDTHS PER FRAME Ji

0090 PRINT=X85A 3 DIRECTS OUTPUT TO PRINTER 3i*

0100 N0PR1NT=ZB4C J NO OUTPUT TO PRINTER 3i

0110 DEL=127( CAN=24( FF=12( CR=13f TAB='9; 3 ASCII CTL 3

0120 PL0T=3i PLTESCAP=3i N0RMLPRT=2( 3 PLOT MODE CTL 3

0130 CPI12=30 3 SET PRINTER DENSITY 12 CHAR/IN 3!

0140 CPIMAX=31 3 SET MAXIMUM DENSITY FDR PLOTTING 3!

0150

0160 VAR I 3 GENERAL-PURPOSE INDEX 3i

0170 IPT 3 CHARACTER INPUT 3,

0180 ABSFLAG 3 TRUE IF ABSOLUTE ADDRESSING CALLED FOR 3i

0190 ORIGIN 3 AIiDRESS OF 1ST BYTE TO BE COriED 3r

0200 LASTBYTE 3 ADURESS OF LAST BYTE TO CODE 3!

0210 POINTER 3 ADDRESS OF NEXT BYTE TO CODE 3.

0220 FRAMEID 3 VALUE OF ID BYTE OF NEXT FRAME 3!

0230 INTEGER!

0240 JOBNAMEt ARRAY [53] OF INTEGER! 0250

0260 FUNC UFRAHE (START,STOP>!

0270 3 WRITE ONE FRAME BEGINNING AT START AND ENDING

0280 AT STOP OR WHEN THE PAGE 13 FULL, WHICHEVER IS

0290 FIRST! RETURN THE ADDRESS QF THE BYTE FOLLOWING

0300 THE ONE LAST ENCODED 3

0310 CONST SYNG=X96 3 FIRST BYTE OF EVERY FRAME i!

0320 VAR ABSCK 3 TRUE IF AN ABSOLUTE ADDRESS IS WANTED 3.

0330 BARCNT 3 NUMBER OF UNIT WIDTHS IN FRAME 3.

0340 CKSUM 3 HEX CHECKSUM 3.

0350 FRAMELEN 3 NUMBER QF BYTES IN FRAME 3.

0360 I 3 GENERAL-PURPOSe INI3EX 3!

0370 INTEGER; 0380

0390 PROC WBYTE (VALUE);

0400 3 WRITE BAR CODE FOR 8 LSD'S OF "VALUE"-3

0410 VAR BUFf I; INTEGER!

0420 BEGIN

0430 BUF != VALUE AND 2SS!

0440 FOR I !- 1 TO 8 BO BEGIN

0450 WRITE (SPACEi BAR3i IF BUF > 127 THEN WFIITE (BAR)!

0460 BUF !- (BUF SHL 1) AND 255 END

0470 END! 0480

0490 FUNC SCANBYTE (VALUE);

0500 3 RETURN THE NUMBER OF UHIl WIDTHS MELDED TO URXTE

0510 BAR CODE FOR 8 LSB'B OF "VALUE" J

0520 VAR IiUFi CNT, i; INTEGER;

0530 BEGIN

0540 BUF VALUE AND 253! CNT t' Oi

0550 FOR I 1 TO 8 DO BEGIN

0560 CNT CNT+2! IF BUF > 127 THEN CNT CNT+1!

0570 3 ONE SPACE + ONE BAR. ■!■ ONE MORE BAR If bL'i IS 1 J

0580 BUF := (BUF SHL 1) AND 255 END!

0590 SCANBYTE i= CNT END!

0600

0610 BEGIN 3 WFRAME 3

062O ABSCK ABSFLAG AND (START <~ STOP)!

0630 WRITE <CPI12)!

0640 IF ABSFLAG THEN WRITE ( START7.) 0650 ELSE WRITE (START-ORIGINX)i

0660 WRITE ( TAB,CPIMAX,PLOT ); WBYTE (SYNC)! FRAMELEN !=" Of

0670 IF ABSCK THEN BEGIN

0680 CKSUM (START SHR S) -!■ (START AND 255)!

0690 BARCNT SCANBYTE (START SHR S) I SCANBYTE (START)

0700 END

0710 ELSE BEGIN CKSUM :^ O; BARCNT '.- 0 END!

0720 IF START <- STDI' THEN REPEAT

0730 I :^ HEM CaiART + FRAMELEN]! CKSUM !" CKSUM + 1!

0740 BARCNT := BARCNT + SCANBYTE (I)!

0750 FRAMELEN !" FRAMELEN + 1

0760 UNTIL (BARCNT > MAXBAR-24 ) OR ( START+FRAMELEN -- STOP+1 )i

0770 IF ABSCK THEN FRAMELEN \' FRAMELEN-; 2!

0780 CKSUM 256 - ((CKSUM + FRAMEID -1 FRAMELEN) AND 255)!

0790 WBYTE (CKSUM)! WBYTE (FRAMEID)! WBYTE (FRAMELEN)!

OSOO IF ABSCK THEN BEGIN

0810 WBYTE (START SHR S)i WBYTE (START)!

0820 FRAMELEN FRAMELEN-2 END;

0830 FOR I 1 TO FRAMELEN DO 0840 WBYTE (MEM tSTART "I 1 - 13)!

0850 WRITE (SPACEi BARr PLTESCAP> NORMLPRTi CPI12s CR)!

0860 WFRAME !- START + FRAMELEN

0870 END! 0830

0890 BEGIN 3 ttt MAIN PROGRAM tm: 3'

0900 CALL (NOPRINT)! I i^- 0!

0910 WRITE ( FF.' BAR-CODE PRIKTER'.(jRi CRi' JOB NAME! ' )S

0920 WHILE I < 53 DO BEGIN

0930 READ (IPT)! CASE IPT OF

0940 del: if I > 0 THEN BEGIN WRITE (IPT)i I I-l END!

0950 can: WHILE I > 0 DO BEGIN WRITE (BEL)} 1 }= 1-1 END

0960 ELSE BEGIN '

0970 WRITE (IPT)! JOBNAME CI] ;- IPTi I I+li

0980 IF IPT = CR THEN I 53 3 TO GET OUT OF LOOP 3 END

0990 END 3 CASE 3

1000 END 3 WHILE 3! JOBNAME C53a ! CR!

1010 WRITE (CR.'START ADDRESS: ' )! READ (ORIGINX)! 1020 WRITE (CRr'END ADDRESS: '); READ (LASTBYTEX); 1030 WRITE ( CR,' SPECIFY ABSOLUTE ADDRESSES,'? ')! 1040 REPEAT READ (IPT) UNTIL ! IPT ■■ 'Y') OR (IPT ■■ 'N')! 1050 WRITE (IPT)! ABSFLAG dPT^-'Y'); 1060 CALL (PRINT)i WRITE (CPI12); I :- -1! 1070 REPEAT I :■- I-t-li WRITE (JOBNAME EI]) 1080 UNTIL JOBNAME CI] = CRJ WRITE (CR)! 1090 POINTER ORIGIN! FRAMEID i- 0! 1100 REPEAT

1110 POINTER WFRAME (POINTER.LASTBYTE)i

1120 FRAMEID :^ FRAMEIDIli

1130 IF (0 FRAMEID MOD S5 ) AND (POINTER <> LASTBYTE)

1140 THEN BEGIN WRITE (FF); I ;■ -i;

1150 REPEAT I :^ Mi; WRITE ( JDCMAliE CIJ)

1160 UNTIL JOBNAME CI] ' CR; WRITE (CR ) END

1170 UNTIL POINTER > LASTBYTE;

liao POINTER WFRAME (POINTER,0) 3 WRITE EOF FRAME 3

1190 WRITE (FF)i CALL (NOPRINT)

1200 END. 3 MAIN PROGRAM 3

230 May 1981 ® BYTE PublicaUons Inc

Circle 394 on inquiry carti.

hen Steinway ncert grancUMy dot romise on ql&lity.

Neither do we.

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The KTM-3 incorporates all the latest features of standard terminals such as:

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24x80 characters in the KTM-3/80 24 X40 characters in the KTM-3

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• "CAPS LOCK" key

• 128 ASCII characters with descenders

• Full and half duplex with modem control

• Built-in power supply and cables included

• Scrolling and full cursor control

• Display of framing and parity errors

• Auto key-repeat

• Debug mode (Display of control characters)

• Built-in diagnostics

• 50/60 Hz operation with 220 volt version avc

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Technical Forums

shoultd find it easy to adapt this routine to their own favorite languages and printers. Figure 1 shows the textually-encoded bar-code representation of a portion of listing 1.

The program need not be used exclusively for software distribution. Transfer of data of any kind between computers with incompatible mass-storage devices is easy if the source computer can create bar code and the recipient can read it. In addition, cheap, compact, archival storage of seldom-used information is possible if the length of files and frequency of use are such that entry via the wand is not unreasonably tedious.

Lest there be any doubt about the suitability of this program for use in software distribution, I will conclude by mentioning a recent experiment. I produced the barcode listing (partially reproduced in figure 1) and photocopied it on a high-quality electrostatic photocopier. Both the original and the copy were scanned five times with the bar-code wand. I counted the number of passes needed to read each line and calculated the average. For the original and the copy, 1.1 and 1.3 passes with the wand sufficed to obtain a good read. Total time to enter the code ranged from 10 to 15 minutes, but this time could be decreased if a portable drafting tool or a T-square were used instead of a ruler to guide the wand across the page. The most time-consuming step in the entry process involved alignment of the ruler. Clearly, it is perfectly feasible to use this method to distribute machine-readable code on paper.!

References

1. Budnick, K. Bar Code Loader. Peterborough NH: BYTE Books, 1977.

2. Chung, K-M and H Yuen. "A Tiny Pascal Compiler, Part 1: The P-Code Interpreter," September 1978 BYTE, page 58. Republished in The BYTE Book of Pascal. B W Liffick, editor. Peterborough NH: BYTE Books, 1979, page 59.

3. Helmers, Carl. "Bar Codes, Revisited...," April 1980 BYTE, page 6.

4. Louis, G. "Tiny Pascal in 8080 Assembly Language," July 1979 BYTE, page 174. Republished In The BYTE Book of Pascal. Blaise W Liffick, editor. Peterborough NH; BYTE Books, 1979.

BYTE'S Bugs

Upslde-Down Static Phoneme

Right in the middle of "Articulate Automata," there's an upside-down vowel spectruml (See photo 3, page 170, February 1981 BYTE.)

Richard T Gagnon R T Gagnon Associates 210 W Tienken Rochester MI 48063

Mr Gagnon is correct: our phoneme spectrum was inverted. Thanks for setting us upright...CMn

Immediate response to your orders

232 May 1981 © BYTE PubUcatlons Inc

Circle 240 on inquiry card.

n GROWTH.

A year ago, the course for Marot Software Systems, Inc. was clear. We were on our way to becoming the world's best source for software. And we were going to accomplish that by distributing only the operating system and the application software that brought out the best in microcomputers. That was our course... and, In all modesty, we were most successful.

That's when something funny happened. The dealers, consultants and computer users with whom we had relationships began asking — and then demanding—that we at Marot apply our expertise and follow-through to the supply of reliable, quality-oriented hardware and complete computer systems. Systems that could solve specific problems in data-based management and analysis for business, law, medicine, science and government.

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ONYX — Extremely powerful and reliable 5-user Z80-based micro, with 10 or 20 Mb liard disl< and integral tape subsystem. Also available: 16 bit Z8000 operating UNIX™ Version 7, with up to 1 Mb RAM for as many as 8 users. 10 or 18 Mb hard disk with Integral tape subsystem and additional storage available.

ALTOS —Cost-effective floppy disk system, 208 K RAM for up to 4 users. Expansion to 58 Mb hard disi< with tape

backup avaiiabie.

The marl<etplace told us of the need for support, too. Of the gap that existed in matching hardware, operating systems and software to application requirements. And of the need for assistance in evaluating options available to meet those requirements.

So, we thoroughly searched and found the best hardware we could distribute.

As a result, Marot Software Systems, Inc. has become Marot Systems, Inc. It's the one company you can rely on to handle total computer needs: from hardware, software, operating systems and support to total computer solutions.

If you're a computer dealer or a computer consultant, Marot's total bacl<up and support could be the special something you need to mai<e your operation grow. Call or write us today.

Here are the products distributed by Marot Systems, Inc. Please check items of interest and return this coupon to:

IVIarot Systems, Inc.

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New York, New York 10017

(212) 661-8550

TWX 710-581-2477

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□ OASIS® — The mini-like single and multi-user machineindependent operating system for Z80 commercial applications and serious programmers.

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□ MAGIC WANDTM —The most usable fullfeature word processing system with extremely powerful text-formatting features.

□ MAROT'S MAILING LIST PROGRAM — Maintains up to 65,000 entries

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ESO-1 is a trademark of Micro

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Systems. MAGIC WAND Is a trademark of

Small Business Applications Inc.

Circle 228 on Inquiry card.

BYTE May IWl 233

HOV/TO MAKE THE STAPN/RITER 25

N^RD-PROCESSIHG PRIKTER GQMMTIDLE WITH YOUR

APPLE, PElTRS-aa

OR DUSIKESS S^TEM:

TheStorwrHvr'" Dois/Wheel 25 q» printet

the best service organizations in the indiistry It can be yours for about $1,895. See your nearest dealer for details.

There's one big difierence between the Starwriter 25 and most other letter-quality printers:

About a grand. (Less.)

Leading Edge Products,Inc., 225 Tbmpike Strevt, Canton, Massachusetts 02021

Dear Leading Edge:

The idea of saving $1,000 doesn't bother xpe, so I'd like to see iny nearest dealer for det^. Now, if I just knew who he was...

B-5

And yet it has some features—like painless interfacing—that are hard to find at awy price. For instance:

Using a 96-character wheel, the C. Itch Starwriter 25 produces excellent letter-quality printing on three sharp copies with up to 163 columns, and offers the most precise claracterplacement available for outstanding print performance.

Name

Title _

The Starwriter 25 comes complete and readyto-use, requiring no changes in hardware or software. It uses easily available, Diablo-compatible ribbon cartridges and daisy wheels, and is "plugin" compatible with a wide variety of systems.

Street. City_ State.

Company

Zip

It also comes with a 3-month warranty from C. Itoh on parts and labor; supported by one of

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Leading Edge Products, Inc., 225 Turnpike Street, Canton, Massachusetts 02021 DEALERS: For immediate delivery from the Leading Edge Inventory Bank™ call toll free 1-800-343-6833 In Massachusetts, call collect (617) 828-8150. Telex 951-624 Dealers, see us at the NCC show, Booth No. 5720/5722.

234 BYTEMiyim

STEPi.l>LUGITIK.

(THERE IS NO STEP #2.)

APPLE"

PET"

TRS-80"

ETC

BYTE May 1981 235

System Notes

for

TRS-80 Models I & III

SuperSoft LISP allows the TRS-80 to become a complete Artificial Intelligence laboratory! It is the tool that takes you to the frontier of Computer Science.

The SuperSoft LISP is a complete and full implementation, (it is NOT a subset!) It contains an efficient garbage collector which optimizes the usage of user RAM, and supports the TRS-80 graphics. Below are some features:

Runs In 16k level II (with only 6K overhead) Fully implements atom property list structure. PROG is supported. FUNARG device Is implemented. Efficient garbage collection. Complete with LISP editor and trace. Allows complete range of single precision numeric data.

Works with old as well as new ROMs. Contains 97 functions. Sample Programs.

The LISP package is supplied on tape or discette and with a complete user manual.

cassette version: (requires 16K level II)

Disk version: (requires 16K disk)

(manual only: $15.00)

$75.00 $100.00

Ail Orders and General Information: SUPERSOFT ASSOCIATES P.O. BOX 1628 CHAMPAIGN, IL 61820 (217) 359-2112 Technical Hot Line: (217) 359-2691 (answered only when technician is available)

Superset

First In Software Technology

TRS-80 TRADEMARK TANDY CORP

Faster BASIC for the Ohio Scientific

John A Sauter, Department of Biochemistry 5426 Med Sd I, University of Michigan, Ann Arbor MI 4KL09

"I don't believe it! The guy who wrote this program didn't know what he was doing." How many times have you seen a program and said that? Well, I never thought I would say it while looking at the Microsoft multiplication routines written for Ohio Scientific's BASIC.

Multiplication routines written in software are slow, especially when accurate to 9 digits. Programmers are always trying to optimize mathematical routines for speed. That's why I was surprised that the main loop for the multiplication routine contained line after line of inefficient instructions.

To comprehend the problem, you need to understand how a software multiplication routine works. For multiplication of large numbers, the process is similar to the longhand method taught in school. The two numbers to be multiplied, the multiplier and the multiplicand, are stored in the floating-point accumulator and the alternate floating-point accumulator, respectively. These accumulators are usually 4 to 5 bytes in length and preferably located in page 0 memory. The low bit of the multiplier is checked to see if it is set: if it is, the multiplicand is added to the product (initially 0); if it is not, no addition occurs.

Next, both the multiplier and the product are shifted 1 bit right (or, alternately, the multiplier is shifted right and the multiplicand is shifted left) and the low bit on the multiplier is checked again. This process is repeated for each bit in the multiplier. Four bytes are required for 9 digits of precision: a great deal of bit shifting must go on. In fact, the bit shifting uses most of the time required for a multiplication routine.

Fortunately, there is a convenient instruction in the 6502 microprocessor for shifting several contiguous bytes 1 bit to the right. The ROR instruction shifts a byte 1 bit to the right, with the carry shifted into the high-order bit, and the low-order bit of the byte shifted into the carry. Successive executions of the ROR instruction on contiguous bytes will shift all of the bytes 1 bit to the right, with the low bit of 1 byte shifting into the high bit of the next.

Listing 1 contains a portion of the Microsoft multiplication routine for the 6502. It is part of the routine that shifts the product 1 bit right. This sequence is repeated four more times in the subroutine, and requires a total time of 85 ;ts (with a 1 MHz clock rate while assuming

236 May 1981 © BYTE Publications Inc

High resolution, dot addressable graphics with vertical resolution of 72 dots per inch and up to 82 dots per inch horizontal resolution.

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Circle 248 on Inquiry card.

BYTE May 1981 237

Systam Notes

Listing 1: Section of the multiplication routine from Microsoft's disk BASIC, written for Ohio Scientific computers. This section can be replaced with a single ROR instruction (ROR $73, where the dollar sign denotes a hexadecimal 73). The replacement accomplishes the same task in much less time.

CODE HNEHONIC TIME (US)

LOC

1946 1948 194A 194C 194E 1950

A9 80 90 02 A9 8 0 46 73 05 73 85 73

LDA #$00 BCC S194C LDA f$BO LSR $73 OKA $73 STA S73

that, on the average, the instruction at hexadecimal 194A is executed only half of the time). This sequence is also in a loop that is repeated for all 8 bits of a multiplier byte, requiring a time of 680 ^s for each subroutine call. Finally, the subroutine is called four (sometimes five) times for each floating-point multiplication. Thus, a total of 2.72 ms is used for each floating-point multiplication. However, the entire listing can be replaced by the single instruction (ROR $73). This instruction requires only 5 us to execute, for a total time of 800 (is for each floatingpoint multiplication: a saving of 1.92 ms for each call to the multiplication routine.

My own tests with the changes have indicated that BASIC requires approximately 4.9 ms to complete a floating-point multiplication on a 9-digit number, whereas with the changes, it takes only 3.1 ms. This is an increase in speed of 37% I

Listing 2: Part of a routine accessed by the addition and subtraction routines in Ohio Scientific's disk BASIC. This section can be replaced by the single instruction ROR $02,X.

LOC

CODE

HNEHONIC

TIHE (US>

1854

A9 00

LDA *$00

2

1856

90 02

BCC $185A

3

1858

A9 8 0

LDA #$80

2

185A

56 02

LSR $02,X

6

185C

15 02

ORA $02,X

4

185E

95 02

STA $02,X

4

Other routines that access the multiplication routines also execute more rapidly. For iiistance, the logarithm routine takes approximately 34.8 ms to complete a 9-digit logarithm; with the changes, it takes only 21.9 ms. This is also an increase in speed of 37%.

Similar mistakes were found in a section of the normalization routine (starting at hexadecimal 1854) accessed by the addition and subtraction routines (see listing 2). This sequence is repeated two more times. It can all be replaced by the instruction ROR $02,X. Another interesting section of the routine occurs at hexadecimal 1879 (see listing 3). This can be replaced by the instruction ROR A, which takes only 2 us to execute. The actual increase in speed for the addition and subtraction routines with the changes installed was too difficult to measure since the routines are fairly rapid compared to the BASIC loops and other program segments used to test

From Ballet on Broadway

to Billiards m Dallas...

. .. people are finding unique ways to use the Powerful SclTronlcs REMOTE CONTROLLER

Whether it's the intricate lightir]g for a Broadwai; Ballet or the simple remote lightir^g of pool tables in a Dallas billiards hall, people are firxding out SciTronics Remote Cor\troller can meet their needs.

Here's Why:

0 Controls 256 BSR remote switches—not just 16 0 Hardware driven—requires minimunfi software 0 No ultrasonic linic—prevents erratic operation 0 No BSR command module necessary

Real Time Clock gives Remote Controller an added dimension!

Real Time Clocks are now available to make your remote controller even more powerful. The RTC feature allows for energy consumption scheduling, event scheduling and much more. Your imagination is your only limitation when It comes to the ways which this RC/RTC combination can be used.

Real Time Clocks feature:

0 Lithium battery bacl<-up

0 Crystal controlled accuracy (.002%)

B Clock generates interrupts (seconds, minutes, hours) for foreground/background operation B Complete software in BASIC to Set and Read clock

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(215) 868-7220 Please list system with which you plan to use peripheral. Master Charge and Visa accepted. PA residents add sales tax. CCD's accepted.

238 Miy 1981 ® BYTE FublkaUoiu Inc

Circle 360 on inquiry card.

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HORIZON RAM ASSM 16K=$389. 32K = $579

HORIZON RAM KIT SALE! 16K = $314 32K = $469

HORIZON DISK DRIVE SALE DOUB DEN SAVEI 31S

NORTH STAR HARD DiSK 18 Mb 4999 $3929

PASCAL-PLUS 14,18 OR 36 DIGIT PRECISION 249

SUPERBRAIN

ZENITH

SUPERBRAIN QD 64K List $399S only $2995

2-89 48K List $2895 only $2299

TERMINALS Z-19$725

INTERTUBEIII oniy$725 DIP-81 PRINTER omy $395

MICROTEK $875

NEC PRINTER $2569 TRACTOR, THIMBLE, RIBBON

InterSystems

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Z-BOA CPU 4 MHz 64K Dynamic RAM Front panel V I/O—with interrupts FDCII Disk Controller 20 slot motherboard

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PASCAUZ + THE FASTEST PASCAL $375 GET READY FOR ITHACA'S Z-8000 8088 16 BIT CPU & SUPPORT CARD SEATTLE $575

MORROW 8" DISK

DISCUS 2D + CP/M® 600K ONLY $938 DISCUS 2 + 2 + CP/M® 1.2 MEGA B. $1259 ADD DRIVES 2D = $650 2 -H 2 = $975 2D-DUAL + CP/M® ONLY $1555

MORROW HARD DISK 26,000,000 BYTES!! LIST $4995 ONLY $3995 CP/M® IS INCLUDED!

SAVE ON MEMORY AND PROGRAMS

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CENTRAL DATA 64K RAM $599 ITHACA MEMORY 8/16-bit 64K $845 SEATTLE MEMORY W16 BrT 16K 4Mhz $275

SSM KITS Z-80 CPU $221 VIDEO BRDV834Mhz $412 ANAOEX PRINTER OP4S0O-1 $1349 CAT NOVATION MODEM $169 TARBELL DISK CONTROLLER DD $445 EC0N0RAM2AaKASSM $179 NSSE 1-22 & P01 TERRIFIC PROGRAMS ONLY $10. EACH NORTHWORD 294 MAILMAN 234 INFOMAN $364

TARBELL COMPUTER-PHONE

RCA-COSMAC VP-111 99 RCA-COSMAC VP-711 $199 COLOR) RAINBOW 38B SPECTRUM $289 EZ-80 Machino Language Tutor $25 EZ-CODER Translates English to BASIC $71

ECOSOFT FULL ACCOUNTING PKG

$31S

BOX OF DISKETTES $29 SECRETARY WORD PROCESSOR

The BestI $99 TEXTWRITER III Book Writing Program $112

GOFAST NORTH STAR BASIC Speeder Upper $71 Which Computers are BEST? BROCHURE FREE'

North Star Documentation rofundabls w/HRZ$20

AMERICAN SQUARE COMPUTERS BEATS ADV. PRICES

square

American [0] Computers

919-889-4577 KiVETT DR. JAMESTOWN N.C. 27282 919-883-1105

circle 16 on Inquiry card.

CP/M Is a registered trademark of Digital Research, Inc.

BYTEMaylSSl 239

System NotM

Listii^ 3: Section from the normalization routine used by the addition and subtraction routines in Ohio Scientific's disk BASIC. This section can be replaced by the instruction ROR A.

LOC

CODE

MNEMONIC

TIME (US)

1879

08

PHP

3

187A

4A

LSR A

2 ■

187B

28

PLP

4

187C

90 02

BCC $1880

3

18 7 E

09 80

OBA t$80

2

1880

C8

INY

them. I did notice that BASIC testing loops often executed approximately 10% faster with the changes. I attribute this to the faster addition routine.

I suspected that the division routines would also contain errors, but discovered that the ROL instruction was used wherever it was needed. (The ROR instruction isn't necessary in division.)

I immediately contacted Ohio Scientific and Microsoft to inform thetn of the problem. Both replied with an explanation that restored my faith in big-name software companies. Apparently, earlier versions of the 6502 microprocessor did not include an ROR instruction, but as customer demand grew, MOS Technology incorporated an ROR instruction in later versions of the 6502. Unfortunately, some of the earlier Ohio Scientific computers had already been sold with the old microprocessor. Therefore, Microsoft wrote its BASIC without any ROR

instructions to make the software compatible with the earlier versions of the computer. Listings 1, 2, and 3 are actually macro expansions of the ROR instruction. [Macros are one-line pseudoinstructions placed in an assembly-language source listing. When processed, they are replaced by a (predefined) set of assembly-language instructions and assembled into machine language....GW] Microsoft assured me that this was done only for the KIM and Ohio Scientific computers. All other versions of 6502 BASIC were written using the ROR instruction.

For those who have later versions of Ohio Scientific computers and don't have BASIC permanently stored in read-only memory, there is a way to change Ohio Scientific's disk BASIC to use the ROR instruction. If you are using the OS-65D disk operating system, the program in listing 4 will permanently change your BASIC for 8-inch disks. It simply loads a part of the BASIC interpreter into memory, POKEs in the required changes, and stores the changed code back on disk. For 5-inch disks, statement 80 should be changed to read:

80 D1SKI"CA 4200 = 03,1" and statement 150 should be:

150 DISK1';SA 03,1=4200/8"

■raUNDERCLOCK PLUS™

PUT TIME AND REMOTE CONTROL IN YOUR APPLE II

The THUNDERCLOCK PLUS is two peripheral systems on or>e card for your APPLE II OR II PLUS. An accurate, reliable, real-time clock/calendar and an interface for the popular BSR X-10 Home Control System.

The THUNDERCLOCK clock/calendar makes accurate time and date available to your programs: month, date, day«of-week, hour, minute, and second, in any of four software selectable formats. On-board batteries keep your THUNDERCLOCK running when your APPLE II is turned off - for up to four years before battery replacement. On-card IK firmware makes reading or setting the time easy from APPLESOFT or INTEGER BASIC, PASCAL, or assembly language programs. And it provides software selectable intemipti at any of three rates: 64> 256, or 2048 interrupts/second.

THE PLUS

Add THUNDER WARE'S X-10 ULTRASONIC INTERFACE OPTION to your THUNDERCLOCK and your programs can send all 22 BSR X-10 commands so you can remotely control lights and appliances. A full 128 dim/bright levels. And a powerful disk software packagel The THUNDERWARE SCHEDULER software lets you create schedules to control lights, appliances, security systems, or almost any other electrical device. The software includes: SCUTIL- the SCHEDULER utility that lets you make or change a schedule, andSCHED- executes your schedules in real-time using the THUNDERCLOCK. SCHED runs in the 'background' so you can run other programs in the 'foreground'.

The THUNDERCLOCK PLUS is a SYSTEM for your APPLE 11. Supported by intelligent, easy to use firmware, a powerful software package, and good documentation!

Available through your dealer. ™uNDERcl"oS^JS.Us!^r„L.„.$l39

Clock/calendar card with batteries and

user's manual

X-10 INTERFACE OPTION $49

BSR X-10 Ultrasonic interface, disk with SCHEDULER SOFTWARE & demos, and

user's manual

PASCAL SOFTWARE $29

Disk with PASCAL interface for clock and X-10 interface, and user's guide

BSR X-10 U a trademark of BSR (USA) LTD. MANUALS ONLY, each $5

APPLE n if • cndemaik of APPLE COMPUTER, INC CalUomU midoili uU 6% nlcs tax

If your dealer doesn't carry the THUNDERCLOCK PLUS: ORDER TOLL FREE (VI8A/MC) CALL: 80O-2Z7-62O4 EXT 307 (Outside CaUfomia) 800-632-2131 EXT 307 (Califbmia Only)

OR WRITE TO:

THUNDERWARE INCORPORATED P.O. Box 13322, Oakland, CA 94661

240 May 1981® BYTE Publlaili«ulnc

Circle 410 on Inquiry card.

thaft^ d^ined to be the head of the class!

The Monroe Educational Computer

What takes ttie Educational Computer to the head of the class is that so many of its "standards" wind up as costly "extras" on other microcomputers. Features like:

• 96K of system RAM Including 32K of user RAM

• over 320,000 bytes of bullt-ln flexible disc storage

• typewriter-style upper and lower case keyboard, 10key numeric pad

• 8-key row of user-definable keys providing 16 additional keyboard functions

• extended BASIC language

• three serial RS232 ports for communications, printers and peripherals

• high and low resolution color graphics with colortext

Monroe gives you much more than hardware. You will have access to a full-range, Monroe-developed, software library that makes this computer so versatile, so powerful, It will serve educational needs from primary to secondary to college levels!

With Monroe, you1l never be left alone with a computer and nowhere to go for help. The Educational Computer will be sold, leased, serviced and personally installed through Monroe's 350 branch offices nationwide.

For full details, fill out the coupon and send to Monroe Education Center.

Monroe Systems For Business The American Road Morris Plains, NJ 07950

An.: Monroe Education Center

Name

Title

Educational facility.

Address

Circle 272 on Inquiry card.

□ MONROE

Systems For Business

City — State

-Zip

Lmon

6809 SOFTWARE POWER TOOLS

BY MICROWARE'^

System Notes

08-9'" MULTIPROGRAMMING OPERATING SYSTEM

/m true multitasking, real time operating system for / % timesharing, software development, database,

L m process control, and other general applications.

This versatile OS runs on almost any 6809-based computer.

■ UNIX'" -like file system with hierarchical directories, byte-addressable random-access files, and full file security. Versatile, easy-to-use input/output system is hardware independent and expandable.

■ Powerful "shell" command interpreter features: I/O redirection, multiple job stream processing, and more. Includes a complete set of utility commands.

■ OS-9 Level Two uses hardware memory management and can address over one megabyte of memory. Also includes pipes and filters for inter-process data transfers.

■ OS-9 l^vel One runs on systems without memory management hardware having up to 56K niemory. □ OS-9 Level Two $495* □ Level One $195

BASIC09™ PROGRAMMING LANGUAGE SYSTEM

Extended BASIC language compiler/interpreter with integrated text editor and debug packajse. Runs standard BASIC programs or minimally-modified PASCAL programs.

■ Permits multiple named program modules having local variables and identifiers. Modules are reentrant, position independent and ROMable.

■ Additional control statements for structured programming: IF ... THEN ... ELSE, FOR ... NEXT, REPEAT ... UNTIL, WHILE ... DO, LOOP ... ENDLOOP, EXITIF ... ENDEXIT.

■ Allows user-defined data types and complex data structures. Five built-in data types: byte, integer,

9 digit floating-point, string and boolean.

■ Runs under 08-9™ Level One or Level Two. □$195*

OTHER OS-9^" FAMILY SOFTWARE

■ Stylograph™ Screen-Oriented Word Processor

■ Interactive Assembler ■ Macro Text Editor

■ Interactive Debugger

BASICS and OS-9 are trademarks of Microware® and Motorola. UNIX is a trademark of Bell Laboratories.* Most software is available on ROM or diskette in versions for many popular 6809 computers. Contact Microware" for specific availability.

For compatible liardware see GIMIX ad page 142.

^^^m MICROWAR6®

= Microware Systems Corp., Dept. B2 = 5835 Grand Avenue, Des Moines, Iowa 50304 ^^^^^ (515)279-8844 • TWX 910-520-2535

I have not been able to test these changes for the 5-inch systems, and 1 suggest that you exercise caution in using them. For systems that use the OS-65U operating system, the program in listing 5 should be used to change your

BASIC.

Ohio Scientific often boasts of supporting the fastest BASIC of any of the popular personal computers, and it can give you a great sense of satisfaction to make it run even faster. I have run BASIC v^ith these changes for four months and have noticed that all of my programs run faster than before, especially those loaded with mathematical equations. If you decide to incorporate these changes into your system, I suggest that you first try them on an old copy of your operating system to ensure that the changes work on your computer. ■

Listing 4: Program used with the OS-65D operating system and 8-inch disks. Beginning at hexadecimal location 4800, the program loads a portion of BASIC into memory, then POKEs the

appropriate ROR instructions into the mathematical routines and stores the revised BASIC back on the disk.

10 REM DISK BASIC CORRECTION ROUTINE. OS-65D, 8" DISKS 20 DATA 118,2,118,3,118,4,104,106,200,208,232,24,96 30 DATA 102,115,102,116,102,117,102,118,102,189,152 40 DATA 74,208,214,96 50 REM SET UP TOP OF MEMORY TO $47PF

60 POKE 132,255 : POKE 133,71 I POKE 128,255 s POKE 129,71

70 REM CALL IN A PORTION OP BASIC TO S4800

80 DISK!"CA 4800=04,1"

90 Al=18516 : REM 18516 = $4854

100 A2=18758 : REM 18758 = ?4946

110 REM POKE IN THE CORRECTED CODE

120 FOR 1=0 TO 12 : READ D : POKE A1+I,D : NEXT I

130 FOR 1=0 TO 14 : READ D : POKE A2-H,D : NEXT I

140 REM SAVE THE CORRECTED BASIC BACK ON DISK

150 DISK1"SA 04,1=4800/8"

16 0 END

Listing 5: Program used with the OS-65U operating system. This program does the same thing as listing 4, but begins at hexadecimal location 7800.

10 REM DISK BASIC CORRECTION RODTINE. OS-650 20 DATA 0,36,0,0,0,2,0,120

30 DATA 118,2,118,3,118,4,104,106,200,208,232,24,96 40 DATA 102,115,102,116,102,117,102,118,102,189,152

50 DATA 74,208,214,96

60 REM SET UP USR FUNCTION AND PUT AND GET ROUTINES 70 POKE 8778,192 : POKE 8779,36 GO POKE 9432,243 :POKE 9433,40 90 POKE 9435,232 : POKE 9436,40

100 REM DISK ADDRESS = $1800 + $0C00, NUMBER OP BYTES = $0200 110 REM RAH ADDRESS = $7800

120 CB=9889 : FOR 1=1 TO 8 : READ D I POKE CB+I,D I NEXT I

130 REM CALL IN A PORTION OF BASIC TO S7800 140 ER=USR(0)

160 Al=30804 : REM 30804 = $7854 170 A2=31046 : REM 31046 = $7946 180 REM POKE IN THE CORRECTED CODE

190 FOR 1=0 TO 12 : READ D : POKE A1+I,D : NEXT I 200 FOR 1=0 TO 14 : READ D : POKE A2-H,D : NEXT I 210 REM SAVE THE CORRECTED BASIC BACK ON DISK 220 ER=0SR(1)iCLOSE 230 END

242 May 1981 © BYTE Publications Inc

Circle 263 on inquiry card.

MICROBYTE INTRODUCES

MORE PROFIT FOR YOUR BOTTOM LINE

32K STATIC MEMORY BOARD

•Fully S100 bus compatible, IMSAI, SOL, ALTAIR, ALPHA MICRO

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•2 MHz or 4 MHz operation

•Gold contacts for tiigher reliability

•Thernnally designed heat sink (board operating temperature 0-70°C) •Commercially designed power bus; 7 ground bus bars; 0.1 uf decoupling capacitors

• Fully tri-state buffered

•Inputs fully low-power Shottky Sctimitt Trigger buffered on all address and data lines •Phantom is jumper selectable to pin 67 •Each 4K bank addressable to any 4K slot within a 64K boundary •4K hardware or software selectable

•One on-board 8-bit output port enables or disables the 32K in 4K blocks •Selectable port address

•4K banks can be selected or disabled on power on clear or reset •Will operate with or without front panel

•Compatible with Alpha l^icro, with extended memory management for selection beyond 64K

• No DMA restriction

• Low power consumption SOOrriA

• Fully warranted for 120 days from date of shipment

I ~-* t

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Z-80A/I-O

•A complete single board Z-80A CPU with serial/parallel interface

• Fully compatible with the proposed IEEE 8-100 Bus Standard •Z-80A CPU (4MHz version of the Z-80)

•158 instructions—superset of and upward compatible from the

8080's 78 instructions

•Up to 4K of on board Eprom with optional Z-80 monitor program —

1 K(2708), 2K(2716) or 4K(2732) •Full vectored interrupt capability •2MHz or 4MHz operation is jumper selectable •Selectable auto-wait state insertion for extending M1', MREQ*,

lORQ* and/or on board ROM

• Dual RS-232 serial I/O ports using the Z80A-DART with individual baud rate selection (16 baud rates from 50-19,200 baud)

• Up to 24 bit parallel I/O port—fully programmable Intel 8255A

• Up to 8 separate counter/timers using 2 Z-80A CTC

aiuu

■I4UUUIUU>">

ifii

DISK CONTROLLER

• DMA to within 16M byte of memory •State-of-the-art NEC765 LSI Controller •IEEE-S100 compatible

• DMA arbitration allows use of multiple boards within a system •PLL data recovery for totally reliable operation

•Write pre-comp switched at mid-disc for reliable double density operation

•Supports up to four (4) drives

• Power On, Power Off or Reset deselects drives to avoid damaging files

•Drive deselect Time Out, deselect drives not in use •Single or double sided operation •Single density/double density operation •8" standard drives

•Separate Vqq supply for data recovery to eliminate possible noise problems

64K DYNAMIC RAM BOARD

• Fully S-100 bus compatible/Alpha Micro compatible •64K X 8 bit dynamic RAM

•Low power: -l- 8VDC @ 700 ma -I- 16VDC @ 100 ma -16VDC ® 25 ma

• Built-in-parity with LED indicator and vector interrupt •Memory addressable in four 16K banks

•Hidden refresh

•Gold contacts for high reiiabiiity •72-hour Burn-in

• Memory mapped via DIP switch

• Built-in programmable write-protect

• Programmable control port for parity and bank control

MICROBYTE has the products — from memory boards to complete S-100 systems, and we offer the rest of the value cluster — call today for the whole story on how you can become a Microbyte dealer.

4 PORT I/O

•Quad RS-232C Serial Ports, One 20mA Current Loop Port

• Fully IEEE S-100 Bus Compatible •Asynchronous Communications with Z80A-Dart(TM) or

Synchronous Communications with Z80A-SiO/0(Tf«1)

• Full Set of Modem Control Signals, including Rl (Ring Indicator)

• Easily Configurable to Any Type of Terminal interface

• I/O Servicing Environments: (1) Polled; (2) Bus Vector; (3) Z80 Mode 2 Vector

•Off-Board interrupt Daisy Chain Capability •Special Receive Conditions: (1) Framing Error; (2) Parity Error; (3) Receiver Overrun Error

• Baud Rates Selected individually from 50 Baud to 300K Baud

• 72 Hour Burn-In

MICROBYTE 1198 E. Willow St., Signal Hill, CA 90806^(213) 595-8571

Circle 253 on inquiry card.

BYTE May 1981 243

Book Reviews

Principles of Interactive Computer Graphics, 2nd Edition

William M Newman arid Robert F Sproull McGraw-Hill, 1979 541 pages, hardcover S25.95

Reviewed by Richard L Emery 559 Taos Ct Saginaw TX 76179

Is your computer a glorified scorekeeper? Was zapping your 10,000th Klingon your most creative accomplishment? Perhaps you have tried to do more, to be more creative. However, the books you found were either too simple ("See Dick run the program. Run, Dick, run.") or too technical ('The vec

tored translation of a quadratic polynomial synthesizing imaginary roots and real coi\straints utilizing classical fourth-order Runge-Kutta numerical techniques...").

With the second edition of Principles of Interactive Computer Graphics, you can explore the special techniques of computer-generated graphics (see page 146 of the December 1977 BYTE for a review of the first edition). The first edition, published in 1973, discussed algorithms and hardware in reference to vector-drawing displays, because these were the most common type of display. At the time, raster-scan displays were available, but programmers mainly used them for data entry and interactiveprogram preparation. When experimenters needed inexpensive, human-readable output devices for micropro

cessor-based computers, the raster-scan method was developed for graphics use. Newman and Sproull recognize this and have included a section devoted to the software techniques needed to implement graphics capabilities on raster-scan displays. This section describes angle and line generation, soUds generation, interactive computation, hardware, and language implementation.

Another major change is the use of Pascal to describe the algorithms. The first edition used a language called SAIL, which required the inclusion of a user's manual. Because of the wide use of Pascal, today's readers will more easily understand the material presented. Even those whose knowledge of Pascal is limited will comprehend the algorithms with little difficulty.

There are twenty-six chapters arranged in six parts. Part 1 discusses line drawing, point plotting, transformations, windowing, and clipping. This material is applicable to raster-scan and vectordrawing displays. In part 2, emphasis is on graphics packages—that is, groups of subroutines to be invoked by applications programs. Part 3 describes the man-to-machine interface. Here, the authors identify several input devices (keyboards, light pens, tablets, three-dimensional input) and methods to use them. In part 4, the following subjects dealing with raster-scan graphics are covered: fundamentals, solid-area conversion, interactive methods, and hardware.

Three-dimensional graphics techniques are more thoroughly examined in part 5, which includes perspective, shading, curved surfaces, and hidden-line/hidden-surface algorithms. Part 6 brings it all together by outlining various hardware display units, methods of user interfacing, and graphics languages. Two appendices are included. The first is a discussion of matrix- and vector-arithmetic operations; the second, homogeneous coordinate techniques. Many of the clipping, windowing, and transformation techniques require a fundamental knowledge of vector and matrix computation. These two appendices provide that knowledge, as long as you understand mathematical notation.

Although this book still is a basic tool for college- and graduate-level computer science courses, the novice or personal computerist will find it understandable. This book will spark your imagination and challenge your creative abilities. Once that challenge is accepted, zapping Klingons will be a bore.B

Introducing...

MINI-FLEX

Designed Specifically to Protect 5" Di

Member of Th© Advance Access

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For Further Information CALL TOLL FREE 800-323-3412

ADVANCE ACCESS GROUP

2200 S. Main St., Lombard, IL 60148 312-629-5800 "Manu/acturers o/ In/ormatf on Processing Supplies"

244 May 1981 © BYTE Publications Inc

Circle 5 on Inquiry card.

Software for the Apple II and Apple II Plus*^

BENEATH APPLE DOS

A Technical Manual

By Don Worth and Pieter Lechner Become an expert on the intricacies of Apple's DOS (DisliOperatingSystem). BENEATH APPLE DOS is the perfect companion to Apple's DO.S 3.3 Manual. Containing eight chapters, three appendices, a glossary, an index, and over 160 pages, this manual will serve to completely fill in the many gaps left by Apple's DOS 3.3 Manual. Written for Apple users with DOS 3.3. 3.2 or earlier versions, any Apple disk user would welcome having this carefully written manual at his fingertips. LEARN ...

• How DOS 3.3 differs from other DOS versions.

• How disks are protected.

• How to reconstruct a damaged diskette CATALOG.

• How tracks are formatted.

• How to use the disk directly, without DOS.

• How to call DOS's hie manager.

• How every routine in DOS works.

• How to customize DOS to your needs.

• How to overcome DISK I/O ERRORS.

• About the "secret" file types — S and R,

INCLUDES . . .

• Large quantities of excellent diagrams and tables.

• Source listings of useful disk utilities.

• Glossary of over 150 technical terms.

• Exhaustive description of DOS program logic.

• Handy reference card

• Useful patches to DOS.

• Ivtany programming examples.

Book-$19.95

CROSS-REF by Jim Aalto

Applesoft programmers will be delighted to have this cross reference Utility program In

their 'tool kit' of software aids. What can CROSS-REF do to speed and facilitate your

Applesoft program development? Consider these functions: VARIABLE CROSS REFERENCE LINE CROSS REFERENCE

FIND VARIABLE FIND LINE NUMBER

REPLACE VARIABLE VARIABLE ONLY LISTING

LINE ONLY LISTING

Features that make CROSS-REF easy to use include:

• Written in machine language, occupies less than 3K.

• Resides passively In memory while DOS or Applesoft is active.

• Can be loaded with your Applesoft program already resident

• Very fast — a VARIABLE CROSS REFERENCE for a 16K Applesoft program can start printing in 5 seconds,

• Contains printer lormat controls and headers for documentation.

• Prints English language error messages.

Cassette - $22.95 Diskette - $24.95

L I

N K E R

LINKER by Don Worth.

Turn your Apple II or Apple II Plus into a powerful and productive software development machine with this superb linking loader/editor package. LINKER does the following and much more:

• Dynamically loads and relocates suitably prepared machine language programs anywhere in RAM.

• Combines a main program with subroutines. You can assemble a subroutine once and then use It with as many main programs as you wish.

• Produces a map of all loaded routines, giving their location and the total length of the resulting module.

• Contains a library of subroutines Including binary multiplication and division, print text strings, delay, tone generator, and random number generator.

Linker works with virtually any assembler for the Apple II. Requires 32K of RAM and one disk drive.

Diskette - $49.95 Manual Only - $19.95

Cassette

FASTGAMMON" By Bob Christiansen. Sound, hi res, color, and musical cartoons have helped make this the most popular backgammon playing game for the Apple II, But don't let these entertaining features fool you — FASTGAMMON plays serious backgammon. Runs on any Apple II with at least 24K of RAM.

$19.95 Diskette - $24.95

METEOROIDS IN SPACE"

By Bruce Wallace

We have taken our popular space game, formerly called Asteroids in Space, and made some important improvements. To accent these improvements we have given it a new name — METEOROIDS IN SPACE. Your space ship travels through a shower of deadly meteoroids. If your ship is hit, it will be destroyed, so you use your laser gun to blast the meteoroids. Big meteoroids shatter into smaller meteoroids when hit and the smaller ones are usually faster and just as deadly. From time to time you will encounter an alien space ship whose mission is to destroy you, so you'd better destroy it first. All the action is displayed in fast, smooth, high resolution graphics, accompanied by sound effects. You now can control your ship using one of two options — the Apple game paddles or the keyboard. One of the game paddle buttons controls the laser fire. In METEOROIDS IN SPACE, the spaceship's velocity gradually decreases unless more thrust is applied, adding an element of control. Also new to this version is a hyperspace feature — translate instantly to another spot in the galaxy. The game is over when five of your ships have been destroyed. An additional ship is added for every 10,000 points you score. Runs on any Apple 11 with at least32K of RAM and one disk drive.

Diskette - $19,95

ASTROAPPLE" by Bob Male. Your Apple computer becomes your astrologer, generating horoscopes and forecasts based on the computed positions of the heavenly bodies. This program offers a delightful and stimulating way to entertain friends. ASTROAPPLE produces natal horoscopes (birth charts) for each person based on his or her birth data. Any two people may be compared for physical, emotional, and intellectual compatibility. The program is written in Applesoft BASIC with machine language subroutines. It requires either RAM or ROM Applesoft and at least 32K of memory.

Cassette - $14.95 Diskette - $19.95

Si^.'.fe FRACAS™ by Stuart Smith.

A fantastic adventure game like no otherl Up to eight players can participate in FRACAS at the same time. Journey in the land of FAROPH, searching for hidden treasure while warding off all sorts of unfriendly and dangerous creatures. You and your friends can compete with each other or you can join forces and gang up on the monsters. Your location is presented graphically and sound effects enliven the battles. Save your adventure on diskette or cassette and continue it at some other time. Both integer BASIC and Applesoft versions included. Requires at least 32K of RAM.

Cassette - $19.95 Diskette - $24.95

BATTLESHIP COMMANDER" by Erik Kilk and Matthew Jew.

A game of strategy. You and the computer each start out by positioning five ships of different sizes on a ten by ten grid. Then the shooting starts. Place your volleys skillfully — a combination of logic and luck are required to beat the computer. Cartoons show the ships sinking and announce the winner. Sound effects and flashing lights also add to the enjoyment of the game. Both Applesoft and integer BASIC versions are Included. Requires at least 32K of RAM.

Cassette - $14.95 Diskette - $19.95

Also by Don Worth ...

BENEATH APPLE MANOR - Adventure. Uses Integer BASIC.

Cassette - $14.95 Diskette - $19.95 BABBLE ' Fun with words, sound, and graphics.

Cassette - $19.95 Diskette - $24.95

QUTiLrry softw7ir€

6660 l?es©da Blvd., Suite 105, (?eseck3, CA91335

(213) 344^599

Now exclusive distributors for products from The Software Factory, NewhaU, California *Apple II and Apple II Plus are trademarks of Apple Computer, Inc.

as

WHERE TO GET IT: Call us at (213) 344-6599 for the name of the Quality Software dealer nearest you. If necessary you may order directly from us. Mastercard and Visa cardholders may place orders by telephone. Or mail your check or bankcard number to Quality Software, 6660 Reseda Blvd., Suite 105, Reseda, CA 91335. California residents add 6% sales tax. SHIPPING CHARGES: Within North America orders must include $1.50 for first class shipping and handling. Outside North America the charge for airmail shipping and handling is $5.00. Pay In U.S. currency.

Circle 339 on inquiry card.

BYTE May 1981 245

TURN MULTI-USER DREAMS INTO PRACTICAL REALITY..

TIES IT ALL TOGETHER

interfaeer 3, an 8 port serial board. Is the answer to the serial Interfacing problems Inherent In multi-user systems. •All 8 channels are true RS-232 with full handshake.

•6 asynchronous DCE Interface channels hook up directly to terminois and printers (no wiring changes required),

•2 asynchronous or synchronous Interface channels (DCE or DTE) are optimized for connection to modems, printers, CRTs, and similar devices,

• Boards may be cascaded for up to 32 channels.

•Includes software programmable Baud rates and many other convenience features.

Like our best-selling Interfaeer 1 and Interfaeer 2 boards, Interfaeer 3 meets the most demanding electrical and mechanical specifications, and Is built to the same stringent standards that have established our position of technical leadership In the

S-lOO field.

Starting in June, multi-user systems wiii be able to enjoy CompuPro quality Interfacing in an extremely convenient format. Interfaeer 3 Is available at finer computer stores world-wide, or order directly from us.

division of

0)E)lB(DI

ELECTRONICS"

BOX 2355, OAKLAND AIRPORT, CA 94614 (415) 562-0636

WHEN YOU TIRE OF TOYS... YOU'RE READY FOR CompuPro.

Sure, "all-in-one" computers can be great intelligent toys; but for scientific, industrial, and commercial applications, toys aren't good enough. You need a computer that works, works right, and keeps on working: you need a precision machine with CompuPro's component-oriented design philosophy,

Lii<e quality component systems for audiophiles, S-lOO component computer systems offer fiexibiiity, ease of maintenance, easy upgrading, resistance to obsolescence, and well- integrated systems performance. Full conformance to ail IEEE 696/S-lOO specifications ensures that CompuPro components wlli work with each other in a reliable, predictable fashion; and our S-lOO engineering expertise, accumulated over 6 years of designing quality components for S-lOO systems, allows us to deliver cost-effectiveness along with outstanding performance.

Ail CompuPro products meet the most demanding mechanical and electrical standards, and are backed with one of the best warranties In the business (1 year limited warranty on all products, 2 year limtted

warranty with exchange program for products qualified under the Certified System Component program).

If you depend on your computer, depend on CompuPro.

NEW! DISK 1: ASUPERB DISK CONTROLLER. A/T $495, CSC $595

finally, a disk controller worthy of ttie CompuPro name. Ttils state of the art design uses properly Implemented DMA with arbitration.

meaning that Disk 1 can co-exist-without any conflict whotsoever-on the same bus as other DMA devices. And because Disk 1 has 24 bit DfvIA addressing capability, you have disk access to a full 16 megabyte memory map.

Speed? Disk 1 tronsfers data independently of CPU speed, and operates efficiently with older 2 MHz CPUs as well as the new lO MHz 8086S. Versatility? Disk 1 handles up to four 8" or 5.25" floppy disk drives (including 96 track high density minifiopples), single or double sided, single or double density (soft sectored). Convenience? Disk 1 includes BIOS for CP/M-80; as well as on-boord boot for automatic startup and on-board 3 wire Interface for system initialization. CompatlbllltY? Disk 1 Is compatible with MP/M% CP/M, OASIS', CP/M80. and CP/M-86. Reliability? Uses industry-standard, third generation controller chips and the same design excellence ttiat Is o part of every CompuPro product.

We weren't going to put out another me-too dlskcontioller..arKi we didn't. The CompuPro Dlik Controller is here.

S-lOO HIGH SPEED MOTHERBOARDS

Actively terminated, fully shielded motherboards handle clock speeds up to lO MHz. Unkits have edge connectors and termination

resistors oresoidered in place for easy assembly. 20 slot motherboard with edge connectors - Unl<it S174, A/T 3214 12 slot motherboard with edge connectors - Unkit S129, A/T SI69 6 slot motherboard with edge connectors - Unkit 589, A/T Sl 29

MEMORIES FROM THE MEMORY LEADER

CompuPro memories feature fully static design to eliminate dynamic timing problems, full conformance to ail IEEE 696/S-lOO specifications, high speed operation (4/5 MHz Unkit. ID MHz A/T and CSC), low power consumption, extensive bypassing, and careful thermal design. Unkit A/T CSC

8KRAM2A S1S9 SI 89 $239

16KRAM14(extendedoddre»lng) S279 S349 S429

16KIWM20-16«»i<>no><««»«irg<Mi»M.»k>c» S319 $399 $479

24K RAM 20-24 (Mmua add,e!i.no ona oar* smeel) $429 $539 S629

32K RAM 20-32 (B'lenaeaodatessing ona bank istecl) • •

.... $559 $699 $799

NEWI 64K RAM 17. Amazingly low power in a 64K lully static RAM

board: draws less than 1.75 Wotts typical. 2.5 Watts maxl Ifs fast, too; runs with 6 MHz Z-80' CPUs, or up to lO MHz with 8086/88 family CPUs. Uses IEEE extended addressing protocol; also, user may turn off 2k windows from EOOO to FFFF In order to accommodate memorymapped peripherals/disk controllers. (The CompuPro disk controller con use the full 64K since it employs properly Implemented DMA techniques). SI095 Unkit, S1395 A/T. S1595 CSC.

Most CompuPro products are available in Unkit form. Assembled/Tested, or qualified under the tilah-rellabHtyCortllled System Component (CSC) program (200 fiour burn-In. more). Note: UnMts ore not intended for novteel. OS de-bugolng may be required due to problems sucli as IC Infant mortoiltY, Foctoty Service Is ovolable for

Unklts at a Hat jervlce ctxsrge.

SYSTEM SUPPORT 1 $295 Unkit, $395 A/T, $495 CSC

This multi-purpose S-lOO board provides sockets for 4K of extended address EPROM or RAM (2716 pinouf) with one battery backup socket; battery backup month/doy/yeor/tlme crystal clock with BCD outputs; optfonal math processor (9511 or 9512); full RS-232 serial port; three 16 bit Interval timers (cascade or use Independently); two interrupt controllers sen/ice 15 levels of Interrupts; power fail indicator; and comprehensive owner's manual with numerous software examples. Conforms fully to all IEEE 696/S-lOO standards. (Add S195 to the above prices for tlie optionai 9512 math processor.)

COMPUTER ENCLOSURE 2

$825 dissk top version, $895 rack mount version

Includes fused, constant voltage power supply (-I-8A at 25 Amps, -I-16V at 3 Amps, and -16V at 3 Amps); 20 slot shielded/active terminated motherboard; and rugged aii-metoi enclosure with dudi AC outlets on rear, heavy-duty line filter, circuit breaker, quiet ventilation fan, and reset svvrftch. Raolt mount version Includes slides for easy pull-out from rack frame.

Also available: COMPUTIR INCLOSUM I. Same as above, but less power supply and motherboard. $289 desktop $329 rock mount.

HIGH SPEED S-lOO CPU BOARDS

CompuPro CPU boards meet oil IEEE 696/S-lOO specifications (including timing). CPU B085/88 uses two processors.an 8085 and 80B8. to provide both 16 and 8 bit capability with a standard 8 bit bus.

8 Bit CPU Z (with ZBOA* CPU) S225 Unkit. S295 A/T, S395 CSC.

8 Bit CPU 8085 S235 Unkit. S325 A/T, $425 CSC.

16/8 Bit CPU 8085/88 S295 Unkit. S425 A/T (both operate at

5MHz); S525 CSC (with 5 MHz 8085,6 MHz 8088).

SOFTWARE

S088/8086 MONITOR-DEBUGGER: Supplied on single sided, single density, soft sectored 8" disk. CP/M* compatible. Great development tool; mnemonics used In debug conform as dosely as possible to current CP/M' DDT mnemonics. S36.

PMCAL/W FROM SORQM: PMCM.-easv to learn, easy to apply-con give a microcomputer with CP/M' more power than many minis, and

SORCIM's PASCAL Is the best we've been able to find regardless of price. We supply a totally standard Vi/lrth PASCAl/M' 8" disk and comprehensive manual. Specify Z-80" or 8080/8085 version. SI 75.

TERMS: Pitesi ihown do not Include dealer Inahallollon and support lenteei. Coniornia reiklents odd tox. Allow a' looit 5% ihlpplnff encew tetunded. Orders under S15 odd S2 hondnnfl. VISA* and MAaTERCAI»0» orders CS25 mintmum) cdtlour M ftoirorder desitor (418) 962.0636. Mclude street oddteu tor yps deSwenr^Prlces ae subisct to crrange wllttout notice.

■LEGAL CORNER: Z80A Is a registered trademark of ZHoo TRSJO Is a trademark of the Tandy Corprotlorv PASCAL/M B a trademark of Sorcirrv CP/M and MP/M ore registered trademarks of DIgltal Research' 0/«IS Is o Iraderndrd of Phase 1.

PRIi CATAIOOi Want more Informotkin? Then send for our free cotatoQ. For tost 1st ck»s dellveiy.add 41 cents m stamps; foreign orders odd $2 (refundable witti order)

(ompuPro"

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Electronics^

COMPUPRO PRODUCTS ARE AVAILABLE AT FINER COMPUTER STORES WORLD-WIDE ...CALL FOR THE STORE NEAREST YOU. circle 169 on Inquiry card

Software Review

INTRODUCING COGNIVOX Series VIO-1000 A Revolutionary New Voice Input and Output Periplieral

High Fidelity Voice Response Industrial Quality Recognition

PET - AIN-65 - APPLE H

COGNIVOX series VIO-1000 is a top-of-the-line voice I/O piMipheral for business and educational applications and ttie riemanding hobbyist,

It can be trained to recognize words or short phrases drawn from a vocabulary of 32 entries chosen by the user. It will talk back with up to 32 words orshort phrases. In disk based systems, response vocabularies can be stored on the disk and brought to memory as needed, giving an effectively unlimited number of vocabulary entries. The quality of voice response is excellent, and it is far superior to that of speech synthesizers.

COGNIVOX series 1000 comes connplete and ready to plug into your computer (the computer must have at least 16K of RAM). It connects to the parallel I/O port of the PET, to the game paddle connector on the Apple and to the J1 port on the AIM-65. Connectors are included as required. Also included are a microphone, cassette with software and extensive user manual. A built-in speaker/amplifier is provided as well as a jack for connecting an external speaker or amplifier.

Software supplied with COGNIVOX includes two voice operated, talking video games, VOTH and VOICETRAP. These games are absolutely captivating to play, and the only voice operated talking games that are commercially available.

Adding voice I/O to your own programs is very simple. A single statement in BASIC is all that is required to say or to recognize a word. Complete instructions on how to do it are provided in the manual,

fn keeping with the VOICETEK tradition of high performance at affordable price, we have priced COGNIVOX series 1000 at the unbelievably low. introductory price of $249 (plus $5 shipping in the US, CA add 6% tax Foreign orders welcome, add 10% for handling and shipping via AIR fvlAIL) When ordering, please give the make and model of your computer, the amount of RAIVl and whether you have disks or not.

In addition to COGNIVOX series VIO-1000. VOICETEK manufactures a complete line of voice I/O peripherals for most of the popular personal computers. Speech recognition-only peripherals are available for the 8K PET and the 4K AIM.

For more information call

address below.

Dealer Inquiries invited.

us at 80.5-685-1854 or write at the

I ^ETE IT B, P.O. Box 388

W Vr I wE I EIV Goleta, CA 93116

Super STEP

Stanley D Robbins, 249 VViUow Ter, Sterling VA 22170

Super STEP is a machine-language utility that works with and is an extension of Radio Shack's T-Bug program. Super STEP allows you to run a machine-language program either by stopping at predefined locations {breakpoints) or stopping after each machine-language instruction is executed {single-stepping).

The TRS-80 video display shows a great deal of information that is useful during debugging, including the instruction currently executed, the contents of the top 5 bytes of the Z80 stack area, the status of all registers and status flags, and a user-specified area of memory. In addition, much of the information is printed twice in order to show these values before and after execution of the current machine-language instruction. Although it is not evident from the documentation supplied. Super STEP is not merely a utility that interrupts program execution after each instruction: it is a simulation (or model) that behaves like an actual Z80.

The instruction booklet that accompanies Super STEP creates the first impression—and that impression is not the best. The small type is difficult to read in good

At a Clanrp

Name

Format

Super STEP Z80

Cassette tape

Processor Model

Language

Type

Machine language

Debugging utility for

assembly-language

Computer

programming (runs as

TRS-80 Model I, with

an extension of Radio

Level II BASIC and

Shack's T-Bug

16 K bytes of memory

program)

Documentation

Manufacturer

Instruction booklet of

Allen Gelder Software

16 pages, 11.5 by 14

Box 11721

cm (4y2 by SVz inches)

Main Post Office

San Francisco CA

Audience

94101

Assembly-language

programiners

Price

$19.95

248 May 1981 © BYTE PublicaUons Inc

Circle 430 on inquiry card.

Circle 182 on Inquiry card.

r

If you need M68000, Z8000,or8086 Software^ take it off our shelf.

1 M€MeNWAY . AhSUttAii S IMC

Mesooo

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Hemenway Associates can give you the software tools you need to get the most out of your ?6-bit hardware. Because 8086, Z8000 and 68000 Systems Software is sitting on our shelves right now.

Single user operating systems, macro assemblers, text editors, floating point pacl<ages, multi-tasl<ing operating systems, linl<ing loaders and PASCAL compilers are all ready for immediate delivery.

You've heard about Hemenway Associates' system designs in the pages of EDN But now you can have Hemenway

H€MeN WAY ASSOCIATES. INC

\X/hen it.eorries to software, come to Hemenway.

designed processor.

to any hardware configui manufacturers evaluation blown microcomputers. It' to-use and backed by oni

So whether you're a microcdl manufacturer, software develoi vidual microcomputer ovwier, has the software for you.

For the hard facts on Hemenway software, write or call: Hemenway Associates, 101 Tremont Street, Boston, Massachusetts' 02108. Phone:617-426-1931. 7WX710321 1203. TELEX 921735.

lighting; in reduced lighting (to facilitate reading of the TRS-80 video screen), the type is almost illegible.

The documentation is very detailed, but it took me a long time to fathom some of the obscure terminology. For example, the author, Alan Gelder, refers to "Z80 Processor Models" (plural), while more conventional terminology would refer to different "states" of the same model. An additional, but more aggravating, example occurs when he refers to "the left IBH columns" and "the right 25H columns" of the TRS-80 video screen. After some thought, I realized that the H at the end of both "IBH" and "25H" referred to hexadecimal notation and that the author intended "IBH columns" to mean "(decimal) 27 columns" (hexadecimal IB equals decimal 27). The video screen is a human interface and, as such, should be described with decimal values, not hexadecimal values.

Based on previous experience with a cassette-only system, I would assume that most (tape-oriented) assemblylanguage programmers have located their programs in memory to just above the top of the T-Bug program; in this way, they can use T-Bug while debugging their program. Since hexadecimal memory locations 4B00 thru 68FF are occupied by Super STEP, the user would be required to reassemble his programs to a location in memory above hexadecimal location 68FF in order to utilize this product (unless the program is relatively small and resides from hexadecimal locations 4980 to 4AFF). Of course, Allen Gelder Software also provides a product

STOP!

Did you remember to remove your Priority One insert? if not please turn bacic to page 80 and

tear it out.

called Super TLEGS; it enables the user to relocate Super STEP (as well as T-Bug) but costs an additional $9.95, bringing the total to $29.90.

The Super STEP program is loaded as follows: load Radio Shack's T-Bug software as a standard "system" tape (from BASIC, type SYSTEM, press the ENTER key, type TBUG, press ENTER, wait for the tape to finish loading); load Super STEP in the same way, using the file name "SPRSTP"; execute the machine-language program by typing a slash followed by the ENTER key (the TRS-80 should respond with a # sign); type S and press the ENTER key. (This procedure is described in the Super STEP booklet.)

At this point. Super STEP fills the video display with information: the right 37 columns fill with a display that shows the current contents of the Z80 (both the prime and unprimed sets of registers), an annotated display of the status byte that shows the flag settings, and some other information. The part of this display that I did understand was very impressive, but I was unable to decipher most of the information in the lower portion. The author describes this display in a photograph on page 3 of the instruction booklet, but his description is neither clear nor thorough.

I then used the T-Bug load (L) command to load a reassembled version (with a new starting address in memory) of the program that I wanted to debug. During the load of a program from tape, Super STEP improves upon the T-Bug loading procedure by displaying the name of the object program on the screen.

(Since Super STEP is an add-on package to Radio Shack's T-Bug program, many of the required commands are explained only in the Radio Shack T-Bug documentation. Consequently, familiarity with the T-Bug program—or at least its documentation—is necessary.)

I displayed a memory location via the memory (M) command. To advance the display to the next location, I depressed the SPACE bar (as directed in the Super STEP instruction booklet), and the equivalent assembly instruction appeared to the right of the first byte of memory I had displayed (a feature that T-Bug doesn't offer); the following byte was then displayed on the following line (as in the normal T-Bug program). To single-step the Super STEP simulation model, depress the SPACE bar repeatedly. This will display memory one byte at a time and update the video display as each instruction is disassembled and executed.

While displaying memory, the semicolon (";") function allows you to view 16 bytes of memory simultaneously, versus the single-byte display of the normal T-Bug program. Another key determines whether this display is in hexadecimal or ASCII. Unfortunately, the display generated on the lefthand side of the video screen sometimes overwrites information on the righthand side. Although this information is correctly updated the next time an instruction is executed, the "garbage" characters remain in the spaces between information fields on the righthand side, making the screen harder to read.

250 May 1981© BYTE PubUcationsInc

QUALITY DISK SOFTWARE

BACKED BY ON-GOING APPLICATIONS SUPPORT

// ® TRS»80 (J

HOME FINANCE PAK I: Entire Series $49.95 ® ®

CHECK REGISTER AND BUDGET: This comprehensive CHECKING ACCOUNT MANAGEMENT SYSTEM not only keeps complete records, it also gives you the analysis and control tools you need to actively manage your account. The system provides routines for BUDGETING INCOME ANO EXPENSE. AUTOMATIC CHECK SEARCH, and BANK STATEMENT RECONCILING. CRT or primer reports are produced for ACTUAL EXPENSE vs BUDGET. CHECK SEARCH DISPLAY RECONCILIATION REPORT and CHECK REGISTER DISPLAY by month. Check entry is prompted by user-defined menus of standard purposes and recipient codes, speeding data entry and reducing disk storage and retrieval time. Six fields of data are stored for eacti check: amount, check no., date, purpose, recipient and TAX DEDUCTIBLE REMINDER, CHECK SEARCH routines allow searching on any of these data fields. Up to 100 checks/mo. storage S39.95

SAVINGS: Account management system for up to 20 separate Savings accounts. Organizes, files and displays deposits, withdrawals and interest earned lor each account $14.95

CREDIT CARD: Get Control of your credit cards with this program. Organizes, stores and displays purchases, payments and service charges for up to 20 separate cards or bank loans $14.95

UNIVERSAL COMPUTING MACHINE: $49.95 ®

A user programmable computing system structured around a 50 row x 50 column table User defines row and column names and equations forming a unique compiiling macliine. Taljle elements can be multiplied, divided, subtracted or added to any other element. Hundreds ol unique computing machines can be defined, used, stored, and recalled, for later use. Excellent for sales forecasts, budgets, inventory lists, income statements, production planning, project cost estlmates-in short for any planning, analysis or reporting problem that can by salved with a table.

COLOR CALENDAR: $29.95®

Got a busy calendar? Organize it with Color Calendar. Whether it's birthdays, appointments, business meetings or a regular office schedule, this program is the perfect way to schedule your activities. The calendar display is a beautiful HI-RES color graphics calendar of the selected month with each scheduled day highlighted in color. Using the daily schedule, you can review any day of the month and schedule an event or activity in any one of 20 time slots from 8:00 A.M. to 6:30 P.M.

BUSINESS SOFTWARE: Entire Series $159.95 ® ®

MICROACCOUNTANT: The ideal accounting system for small businesses.

Based on classic T-accounts and double-entry booking, this efficient

program provides a journal for recording posting and reviewing up to 1,000

transactions per month to any one of 300 accounts. The program produces

CRT and printer reports covering:

TRANSACTION JOURNAL BALANCE SHEET

ACCOUNT LEDGERS INCOME ANO EXPENSE STATEMENT

Includes a short primer on Financial Accounting. (48K) S4995

UNIVERSAL BUSINESS MACHINE: This program is designed to SIMPLIFY and SAVE TIME for the serious businessman who must periodically Analyze. Plan and Estimate. The program was created using our Universal Computing

Machine and it is programmed to provide the following planning and forecasting tools.

CASH FLOW ANALYSIS SALES FORECASTER

PROFORMA PROFIT & LOSS SOURCE AND USE OF FUNDS PROFORMA BALANCE SHEET JOB COST ESTIMATOR REAL ESTATE INVESTMENT INVENTORY ANALYSIS

Price, Including a copy of the Universal Computing Machine $89.95

BUSINESS CHECK REGISTER AND BUDGET: Our Check Register and Budget programs expanded to include up to 50 budgetable items and up to 400 checks per month. Includes bank statement reconciling and automatic check search (48K) S49.95

ELECTRONICS SERIES VOL I & II: Entire Series $259.95

LOGIC SIMULATOR: SAVE TIME AND MONEY. Simulate your digital logic circuits before you build them. CMOS. TTL. or whatever, if it s digital logic, this program can handle it. The program is an interactive, menu driven, full-fledged logic simulator capable of simulating the bit-time response of a logic network to user-specified input patterns. It will handle up to 1000 gates, including HANDS. NORS, INVERTERS, FLIP-FLOPS. SHIFT REGISTERS. COUNTERS and user-defined MACROS up to 40 user-defined random, or binary input patterns. Accepts network descriptions from keyboard or from LOGIC DESIGNER for simulation $159.95 (A)®

LOGIC DESIGNER: Interactive HI-RES graphics program for designing digital logic systems. Draw directly on the screen up to 10 different gate types including NANO. NOR, INVERTER. EX-Oa T-FLOP. JK-FLOP. D-FLOP. RS-FLOP. 4 BIT COUNTER and N-BIT SHIFT REGISTER. User interconnects gates using line graphics commands. Network descriptions for LOGIC SIMULATOR generated simultaneously with the CRT diagram being drawn $159.95(J)

MANUAL AND DEMO DISK: Instruction Manual and demo disk illustrating capabilities of both program (s) $29.95

ELECTRONIC SERIES VOL Ml & IV: Entire Series $259.95

CIRCUIT SIMULATOR: Tired of trial & error circuit design? Simulate & debug

your designs before you build them! With CIRCUIT SIMULATOR you build a model of your circuit using RESISTORS. CAPACITORS INDUCTORS TRANSISTORS. DIODES. VOLTAGE and CURRENT SOURCES and simulate the waveform response to inputs such as PULSES, SINUSOIDS SAWTDOTHS, etc.. .all fully programmable. The output is displayed as an DSCILLDSCDPE-STYLE PLOT of the selected waveforms (Apple only) or as a printed table of voltage vs time. Handles up to 200 notes and up to 20 sources. Requires 48 RAM $159.95,0 (J)

CIRCUIT DESIGNER: Interactive HI-RES graphics program for designing electronic circuits. Draw directly on the screen up to 10 different component types, including those referenced above. Components interconnect list for CIRCUIT SIMULATOR generated automatically. Requires $15995

MATHEMATICS SERIES: Entire Series $49.95

STATISTICAL ANALYSIS I: This menu driven program performs LINEAR REGRESSION analysis, determines the mean, standard deviation and plots the frequency distribution of user-supplied data sets. Printer. Disk, I/O routines $19.95

NUMERICAL ANALYSIS: HI-RES 2-Dlmensional plot of any function. Automatic scaling. At your option, the program will plot the function, plot the INTEGRAL plot the DERIVATIVE, determine the ROOTS. MAXIMA. MINIMA. INTEGRAL VALUE $19.95

MATRIX: A general purpose, menu driven program for determining the INVERSE and DETERMINANT of any matrix, as well as the SOLUTION to any set of SIMULTANEOUS LINEAR EQUATIONS $19.95

3-D SURFACE PLOTTER: Explore the ELEGANCE and BEAUTY of MATHEMATICS by creating HI-RES PLOTS of 3-dimensional surfaces from any 3-varlable equation. Disk save and recall routines for plots. Menu driven to vary surface parameters. Hidden line or transparent plotting $19.95

ACTION AOVENTURE GAMES: Entire Series $29.95 ®

RED BARON: Can you outfly the RED BARON? This fast action game simulates a machine-gun DOGFIGHT between your VlfORLD WAR I BI-PLANE and the baron s. You can LOOP. DIVE, BANK or CLIMB-and so can the BARON. In HI-RES

graphics plus sound $14.95

BATTLE OF MIDWAY; You are in command of the U.S.S. HORNETS' DIVEBOMBER squadron. Your targets are the Aircraft carriers, Akagi, Soryu and Kaga. You must fly your way through ZEROS and AA FIRE to make your OIVE-BOMB run. In HI-RES graphics plus sound $14.95

SUB ATTACK: It's April 1943. The enemy convoy is headed for the CONTROL SEA. Your sub, the MORAY, has just sighted the CARRIERS and BATTLESHIPS' Easy pickings. But watch out for the DESTROYERS - they're fast and deadly. In HI-RES graphics plus sound $14.95

FREE CATALOG-AII programs are supplied on disk and run on Apple II w/Disk & Applesoft RDM Card & TRS-80 Level II and require 32K RAM unless otherwise noted. Detailed instructions Included. Orders shipped within 5 days. Card users Include card number. Add $1.50 postage and handling with each order. California residents add 6t6%sales tax. Foreign orders add $5.00 postage and handling.

SPECTRUM SOFTWARE

142 Carlow, P.O. Box 2084 Sunnyvale, CA 94087

FOR PHONE ORDERS: (408) 738-4387 DEALER INQUIRIES INVITED.

circle 384 on Inquiry card.

BYTE May 1981 251

Exiting the "M(emory)" mode and reentering it at the entry point of my program, I depressed the ":" key to invoke the Super STEP trace function (ie: automatic singlestepping). I then watched my program "execute" for a while, instruction by instruction! The ":" (trace) function more than justifies the inclusion of the word "super" in the name of this product.

An additional feature is the ability to run Super STEP at two different speeds while tracing; at the slow speed, you can see individual instructions as they execute, while at the fast speed, only the registers of the display are readable.

While tracing a program, I found an error in the interaction between the halt ("Z") and trace (":") commands. Use of the "Z" key is supposed to immediately stop the automatic tracing of program execution. It does, but it may stop in the middle of a 2- or 3-byte instruction. The problem at this point was only aesthetic, but when I resumed tracing by pressing the ":" key, Super STEP took the next byte (in the middle of an instruction) and tried to interpret it as the first byte of a new instruction. This can result in the execution of an incorrect Z80 instruction.

A potential annoyance arises in the processing of a CALL or a RST (restart) instruction when tracing or single-stepping a section of a program: if the invoked subroutine is bug-free, it is irritating to slowly single-step through all the subroutine code to get back to the main routine that is being debugged. Super STEP tries to solve that problem via the "*" function. If this function is

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turned on, CALLs and RSTs will not be followed but will be "directly executed" (ie: the single-stepping is turned off during the execution); if this function is turned off. Super STEP will trace or single-step through all program code. However, this command is inconvenient when you want to step through some subroutines but not others. When I'm single-stepping through some code, I can't turn the "*" function on before a routine I don't want to trace — by the time I see the CALL statement, I've already started single-stepping through the routine.

Some improvements come to mind. 1 would like to see some indication of interrupt status (enabled or disabled) on the video display. In addition, Super STEP would be greatly improved if the author provided three copies of the software (one each for the 16 K-byte, 32 K-byte, and 48 K-byte versions of the TRS-80) that would load in the top end of the computer's memory. It would be nice if Super STEP could be rewritten to include all of the T-Bug functions: it could then be sold as a stand-alone product. [On the other hand, the additional time required to add such features is often unavailable to small software companies. If the author did incorporate these features, the necessary increase in price would probably be greater than the cost of T-Bug....GYl]

Conclusions

• One of the most outstanding features of Super STEP is its ability to single-step or trace through any Z80 code,

even routines in ROM; this power is due to the fact that Super STEP is a software program that simulates the Z80, so it has complete control of any program it is executing.

• On the negative side, the documentation for Super STEP is inadequate. I had to reread the instruction manual and experiment with the software in order to figure out how to use it. Users with less patience or machine-language experience will probably have trouble with this product.

• Overall, I think that the Super STEP package (in conjunction with the Super TLEGS program for an additional $9.95) will be useful to the serious assembly-language programmer with a tape-based TRS-80. Its utility is decreased if you have a disk system (I don't know if you can save it to disk), but it still has some features that the TRSDOS DEBUG program (supplied with the TRS-80 disk operating system) doesn't have.H

BYTE'S Bugs

Problematic Problem Solving

The article entitled "Machine Problem Solving" (November 1980 BYTE,, by Peter Frey) has a bug on line 230 of the "Treasure Search" game. (See page 258, listing 1.)

The line should read:

230 X$= RIGHT$(STR$ (B(I),l)):GOSUB 1000

Many thanks to those who called us about this typographical error. ■

252 May 1981 © BYTE Publications Inc

Circle 161 on inquiry card.

DOWN-TO-EARTH PRICES ON OUT-OF-THIS-WORLD PERSONAL COMPUTERS AND COMPONENTS.

Look at this!

Ohio Scientific Superboard II

$299

• It's the first complete computer system on a board.

• Superboard II uses the ultra powerful 6502 Microprocessor

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• Full 53-key keyboard, with upper and lower case. Plus user expandability.

• Video interface and audio cassette interface.

The Ohio Scientific Superboard II at $299 — in today's economy — has got to be the best buy by far. It will entertain you with spectacular graphics made possible by its ultra high resolution graphics and super fast BASIC. It will help you in school or industry, as an ultra powerful scientific calculator. Advanced scientific functions and a built-in "immediate" mode allow you to solve complex problems without programming.

The Superboard II can be expanded economically, for business uses, or to remotely control your home appliances and security. Even communicate with other computers.

Read what's been written about Superboard II:

"We heartily recommend Superboard II for the beginner who wants to qet Into microcomputers with a minimum cost. A reaf computer with full expandability." —POPULAR ELECTRONICS, MARCH 1979

"The Superboard II is an excellent choice for the personal computer enthusiast on a budget."

—BYTE. MAY 1979

Look at these easy hardware prices:

610 Board For use with Superboard II and Challenger 1 P.

8K static RAM. Expandable to 24K or 32K system total.

Accepts up to two minj-floppy disk drives. Requires + 5V

@4.5 amps. 5 298

Mini-Floppy Disk Drive Includes Ohio Scientific's PICO DOS

software and connector cable. Compatible with 610

expander board. Requires + 1 2V @1.5 amps and +5V @

0.7 amps. [Power supply & cabinet not included.] 299

830 Board Contact us for important details. 229

AC-3P 12" combination black and white TV/video monitop. 159

4KP 4K RAM chip set. 78

P8-005 5V 4.5 amp power supply for Superboard II. 45

PS-003 12V power supply for mini-floppies. 45

RF Modulator Battery powered UHF Unit. 35

CS-900B Metal case for single floppy disk drive and power

supply. [While stock lasts.] 49

AC-12P Wireless remote control system. Includes control.

console, two lamp modules and two appliance modules, for

use with 630 board. 175

AC-17P Home security system. Includes console, fire

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with 630 board. 249

C1P Sams C1P Service manual 8

C4P Sams C4P Service manual 16

C3 Sams Challenger III manual 40

Ohio Scientific and independent suppliers offer hundreds of programs for the Superboard II, in cassette and mini-floppy form.

Freight Policies Al orders of $100 or more are shipped ireightprepaid. Orders of less then £100 please add S4.b0 to cover shipping costs. Ohio residents add 5.5% Sales Tax.

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BYTE May 1981 253

Software Review

Wordsmith

—At a Glance —

Software

Wordsmith page-oriented word processor

Use

Word processing

Manufacturer

Scion Corporation 8455-D Tyco Rd Vienna VA 22180 (703) 827-0888

Price

Wordsmith word processor (CP/M or North Star): $295; Screensplitter video board (86 characters by 40 lines) and firmware; $395. Video subsystem (Wordsmith, Screensplitter board, firmware, 15-inch greenphosphor video monitor, and high-quality wordprocessor keyboard IBM Selectiic U style): $1795

Features

Wordsmith word processor (software) runs with a memory-mapped video display (the Screensplitter) with 86 characters per line and 40 lines. Wordsmith is completely reentrant and is

written in 8080 assembly language

Operating System

CP/M 8-inch or North Star 5-inch (single-, double- or quad-density) floppy-disk formats; also IMDOS, MDOS, CDOS (single-, double-, or quad-density formats)

Hardware Any S-100 8080- or Z80-based microcomputer. Wordsmith will run in a CP/M system with only 16 K bytes of memory. The Scion Screensplitter memory-mapped video board is required.

Documentation 66-page manual, 21 by 27.5 cm {BVi by 11 inches), for Wordsmith; 70-page manual for Screensplitter (same size)

Firmware

1 K bytes of video-display software in a 2708 EPROM

Audience

Anyone requiring highquality word-processing capability

Mark Dahmke, 1515 Superior Apt 15, Lincoln NE 68521

The greatest compliment I can give Scion

Corporation's Wordsmith is that I am using it to write this review. I have searched long and hard for a word processor that would give me the features and capabilities of a big-system full-screen editor.

I used to do all of my writing on an IBM 370 computer, using a full-screen editor and a batch program that read in my text and formatted it for a high-speed printer. The full-screen editor was adequate, but the batch program was painful to use because you couldn't see the results without running it (over and over). It was like using a compiler instead of an interpreter—you had to wait.

Wordsmith combines the features of a good, full-screen editor (one of the nicest I have used) in a "what you see is what you get" format, thus allowing text to appear on the screen exactly as you want it printed.

Wordsmith Overview

Wordsmith runs on an 8080- or Z80-based microcomputer with either CP/M or North Star disk operating systems. The distribution disk also supplies a customization program that allows the user to define the ASCII codes of the special-function keys, the location of the memory-mapped video display, and the printer interface.

Unlike many other word processors, Wordsmith is page-oriented, ie: page boundaries are maintained in the disk file. Scion's Screensplitter video display has 86 characters per line and 40 lines, but Wordsmith uses the top line as a "scoreboard" to keep track of cursor position (line and column numbers), current page, total number of pages, and the maximum number of pages that can be used within the disk file that is currently open. The file name (fully qualified by the conventions of the operating system in use) is also shown on the scoreboard. The right portion of the scoreboard is used to enter commands. Getting to the command line is easy—just hit Break, or the key you have assigned to that function. The command line then becomes active, shows a cursor, and awaits your input. Hitting Break again terminates command entry and executes the command. If no command is entered (ie: if you hit Break twice without entering a command), nothing will happen. Wordsmith has over seventy commands, not including those used for cursor movement (up, down, left, right, etc).

About the Author

Mark Dahmke is a consulting editor for BYTE magazine. He also operates a computer consulting business called MCD Consulting and is involved in the design of office automation systems. His interests include astronomy, science fiction, writing, and painting.

Other Features

Wordsmith has many other features that make text entry less tedious. The tab-stop line allows you to set up any number of tabs in a given text file. When you enter the ET command, Wordsmith displays a reverse-video line just below the scoreboard. You can place a period wherever you want a tab stop, and Wordsmith will remember the tab-stop line (the line of periods) for each separate disk file. Once set up, the tab stops may be altered by entering the ET command again.

The hold area is a reserved area of memory that can be used to save up to an entire screen page (86 characters by 39 lines). Using this feature, any amount of text, from a single word or line to an entire screen page, may be copied to another part of the screen, another page in the file, or another disk file. Many commands are available for copying the held text back to the screen. For example, it may be put down "literally," meaning that it will be placed on the screen just as it was copied from the screen. The PF, or put-formatted command, will reformat the

254 May 1981 © BYTE PubUcations Inc

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Store Address

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Phone 403 320-1264

Hours • 10 A.M. to 5 P.M. Monday

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1353 PORTAGE AVE., WINNIPEG, MANITOBA, R3G 0V5

(204) 786-3381

circle 79 on inquiry card.

PET, CBM are registered TM's of Commodore International TRS-80 is a registered TM of Tandy Corporation APPLE is a registered TM of Apple Computer Inc. SORCERER is a registered TM of Exidy Inc.

Last August, Chris Morgan and I went to Washington DC to see a networked office-automation system that Scion had installed in a congressman's office. The system, called Rosenet, consists of a network of Z80 microcomputers running a modified version of the North Star disk operating system. Each workstation also includes a Wordsmith video subsystem. All workstations are tied to a central microcomputer that maintains data bases and an electronic mail/ memo system. The master system also provides printer and dial-up modem services to the workstations, which communicate with the master through RS-232C lines running at 19,200 bits per second....MCD

text in the hold area to fit a new shape or region of the screen. This allows you to work easily with "newspaper columns."

Up to 20 text windows may be defined on each page. Wordsmith keeps track of the windows on each page and the cursor location within each window. This extra information is stored in blocks at the end of the text file, which allows the file to be read in by an assembler or compiler without interference. A window may be any size, from 1 by 2 characters to a whole screen page. This feature is most useful in "cut and paste" operations. When several windows are defined on a page (the screen itself is called the base window), you can move from window to window by hitting the Cycle key. This moves you to the next window in the loop, and eventually returns you to the one you started at. When a window is active, it is im

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CP/M« V.2.2 for Z89 $ 150 $ 140

HDOS Operating System (with BASIC) 2.0 $ 150 $ 140

Microsoft BASIC V5.1 for CP/M $ 175 $ 160

Microsoft BASIC V4.7 for HDOS $ 150 $ 140

Microsoft FORTRAN $ 195 $ 180

Microsolt COBOL $ 395 $ 350

Word Processing for Z89 $ 395 $ 376

16K Expansion to 64K Memory $ 150 $ 140

MICROSOFT BASIC SOFTWARE FOR 289

Accounts Payable $ 550

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EXTENDED PARTS WARRANTY • Ljw-Cost protection to keep your system up and running. We stock spares for immediate shipment. Telephone consulting loo. To Order: Send Check or Money Order to PK Systems. Inc., 113 North Center, Bloomington, IL 61701. Allow two weeks for personal checks to clear. For COD Orders, add.S", for handling and service charge. Rush orders, add $50.00

Shipping: Freight collect, FOB Bloomington. We ship UPS, air freight, or motor freight. PK Systems is an Authorized Zenith Data Systems Dealer and Zenith Service Center.

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possible to type text or move the cursor to a location outside the window. It's like having a miniature screen within a screen. Windows are also useful for setting up templates—k^zs with no text, but with a window structure. A template might, for example, be set up to look like a standard letter format with header, body, closing, and so on. It is then a simple matter to fill in the blanks when writing the letter.

A large selection of cursor-movement commands is available, beginning with the obvious: up, down, left, right and home (move to the upper lef thand corner of the window). On the video-subsystem keyboard, typing Shift in combination with one of the cursor-direction keys causes movement of the cursor in increments of eight character positions, instead of one. Also included are: delete to end of line, move to end of line, delete character, backspace, insert blank, insert mode, delete left, and tab.

Line control and movement commands include: insert line, delete line, insert multiple lines, delete multiple lines, center line, hold multiple lines (in hold area), split line and join line, and search line for string.

Among the window control and movement commands are: open window, clear window, set mark, clear marks, open line window, open paragraph window, drop window, drop all windows, cycle (to next window), go to base window, jump window (to new location on screen), illuminate all windows (ie: set to reverse video), change size transparently, change size, fill window (from hold area), adjust window (right justify), hold window, put text literally (from hold area), put text formatted, erase window, search for string, and search and replace string.

Page Control and Movement

Pages may be inserted and deleted, up to the limit of

pages allowed in a disk file. When a new file is created (using the new-file command), you must specify the number of pages you require. Other commands include: NP (flip to next page), PP (flip to previous page), PGn (go to page n), PG+n (go forward n pages), PG—n (go backward n pages), IP (insert page), DP (delete page), CP (reread current page off disk), SP (split page into two pages—split at the cursor), JP (join two pages), save and recall page templates (window structures).

Disk-File Management

Files can be created with the NF (new-file) command. For example, the command NF B:TEST-10 will create a file (under CP/M) on the B disk called TEST, with room for ten text pages. The command OF B:TEST will get the old file called TEST from the B disk. The page that was saved in the previous editing session will be redisplayed on the screen. CL (close file) ends an editing session and closes a file. Since text pages are not necessarily in sequential order in a file, the SQ (sequence file) command will sort them into order. (This is not needed for normal operations, except when Wordsmith files are being used to store programs or other information that will subsequently be read by another program, such as an assembler or BASIC compiler.) Other file-level commands include: SRFs (search file for string "s"), SUFs (substitute next occurrence) and SAFs (substitute all occurrences in file)."

JSb May 1981 © BYTE Publications Inc

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BYTE May 1981 257

Wordsnlih t.S EnhQnC«M«n-l To ftlel touch -twtM-ts*

lO Qlf v™-.- -w -- t*"*"^

-H>Bltio».ii of »o»t Vlrx ot

us o uarnlna -ttvi* fiJr-th.r _

Is Blnllor to the beC I ftjnc-tlon on convt^it onlw irt>or±ant on th« (a«t llfW frdtt^c of -the Uor-danlth.

tu^d In^o th» lo«t few cJw-oct. 4* X-af^B<l will oti-t be dl5P*orjp«l.

on coovsnt lono I ■ »

of o ulndaw becius* of tt« Quto •woi

nwd. If olt of tt* poultion uiU nal Tit ,tw Fol louino I i™. Itw

Mh«-n Q docunsnt Is »xl-t»U »lth*r low q Close FI lif, tlwu File, DldFilr. or EXkt connond, Hoi-tlBnIth will first wer-lf^« -ItTat «w prot>«- diskrt^ Is loadvd Into the disk drive conparlna tHe docunent rtane against ■the directory of the loaded diskette. If a natch la fotind. «>• currently opened file ul I I be closed. This «uards owalnst diskette* being Interchanged ot Inapproprlot* tines. Refer to the hiornlnfl <r» the eKplanatlon of the CF connand on poae 41 of the nonuat.

Photo 1: The Wordsmith word processor as displayed on the SereenspUtter video board.

Printer Control

Scion supplies the intelligent printer interface of your choice. Printers currently supported include the Diablo 1610, 1620, 1650, NEC 1510, 1520, Qume Sprint 5, and any printer that accepts only carriage return, line feed, and form feed as control characters. A printed page may range from 1 to 255 lines in length. The user has control over the top margin, left margin, and number of lines per

page. All hard-copy commands (except Type Window) begin printing from the cursor line and proceed through the file. The format for all five commands is:

{.Command)-{t)Al)Ah)

where t is the top margin (defaults to 4 lines), / is the left margin (defaults to 4 columns), H is the number of lines per page (defaults to 50).

If all defaults are used, Wordsmith will format output for an 8V2- by 11-inch page. Control-S may be used to temporarily stop printing, and Control-K may be used to abort the print command.

The available printer commands are as follows:

• TCL (type continuous literally): The entire document is printed on the printer, starting on the current page and the current cursor line. Any blank lines at the bottom of a screen page will also be typed.

• TSL (type sheets literally): Wordsmith will pause after printing each page and await a carriage return from the keyboard. This permits use of single sheets of paper (eg: letterhead paper).

• TCC (type continuous compacted): Similar to TCL except that any blank lines at the end of each screen page will be ignored.

•TSC (type sheets compacted): Similar to TCC except that Wordsmith will wait for a carriage return at the end

of each page.

• TW (type window): The current window is typed. This command is useful for cut-and-paste operations and for previewing portions of the document prior to final printing.

Wordsmith also allows the defirution of page headers and footers. When a header or footer is set up, you may specify where it is to start (on what printed page) and, if page numbers are used, with which number it should begin. The page number will be inserted automatically anywhere in the header or footer where you have typed three pound signs (#) in a row. The page number will be left-justified within this field.

Software Problems

No software product is without its bugs, but Wordsmith is very reliable (it has never caused text to be lost).

There are, however, some minor, annoying problems. First, the header and footer commands don't work properly if the default parameters are changed. Second, if no files are open and you issue a save-page command, the program may write over the file pointed to by the FCB (File Control Block) in the CP/M version. Otherwise, Wordsmith performs excellently, and the company, anxious to overcome any bugs, will often give you corrections over the phone (assuming you know 8080 assembly language).

Conclusions

The Wordsmith/Screensplitter combination forms one of the best word processors I have ever used, either on a microcomputer or a large system. The command repertoire is extensive, yet easy to use and learn. Many of its features are not available on word processors of any size or price. ■

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error (red) indicator lights Drive Activity indicator lights Disk Operating System Firmware CBM 8050

(12KROM) Qual Priced 1795

Disk Buffer (4K RAM) ^ I /

DOS version 2.0 Sequential file manipulation Sequential user files Relative record files Append to sequential files Improved error recovery Automatic diskette Initialization Automatic directory search Command parser for syntax validation

Program load and save

CBM^'" 8000 SERIES BUSINESS COMPUTERS

The new Commodore 8000 series computers offer a wide screen display to show you up to 80-character lines of information. Text editing and report formatting are faster and easier with the new wide-screen display. The 8000 series also provides a resident Operating System with expanded functional capabilities. You can use BASIC on the 8000 computers in both interactive and program modes, with expanded commands and functions for arithmetic, editing, and disk file management. The CBM 8000 series computers are ideally suited for the computing needs of the business marketplace. SCREEN

2000 character display, organized into twenty-five 80-column lines

64 ASCII, 64 graphic characters 3 X 8 dot matrix characters Green phosphor screen Brightness control Line spacing: 1'/? in Text Mode

1 in Graphics Mode

KEYBOARD

73-key typewriter style keyboard

witti graphic capabilities Repeat key functional with

all keys MEMORY

CBM 8016:16K (15359 net)

random access memory (RAM) CBM 8032; 32K (31743 net)

random access memory (RAM). POWER REQUIREMENTS Volts: 110V Cycles: 60 Hz Watts: 100

SCREEN EDITING CAPABILITIES Full cursor control (up, down, right, left)

Character Insert and delete Reverse character fields Overstrlking

Return key sends entire line to;

CPU regardless of cursor

position INPUT/OUTPUT Parallel port IEEE-488 bus 2 cassette ports Memory and I/O expansion

connectors FIRMWARE 24K or ROM contains:

BASIC (version 4.0) with direct

(Interactive) and indirect

(program) modes 9-digit floating binary arithmetic Tape and disk file handling

software

CBM 8032 Computer $1795

CBM PRODUCT DESCRIPTION PRICE

4016 16K RAM-Graphi(»(N) or BusinessP)

Keyboard $ 995.00 4032 32K RAM-Graphics(N) or Business(B)

Keyboard $129S.OO 8032 32K RAM-80 Col. Screen-Business

Keyboard $1795.00

4022 Tractor Feed Printer $ 795.00

4040 Dual Floppy-343K-DOS 2.0 - $1295.00

8050 Dual Floppy-974K-DOS 2.0 $1795.00

4010 Voice Synthesizer $ 395.00

8010 300 Baud IEEE Modem $ 279.95

C2N Cassette External Cassette Drive $ 95.00

CBMto IEEE CBM to 1st IEEE Peripheral $ 39.95

IEEE to IEEE IEEE to 2nd IEEE Peripheral $ 49.95

2.1 DOS DOS Upgrade for 2040 $100.00

4.0 DOS O/S Upgrade for 40 Column Computer $100.00

Word Pro 4+ Word Processing Software used w/8032 $ 450.00

*CBM is a registered trademark of Commodore. All prices and spepifications are subject to change without notice.

^ commodore

NEECO

679 HIGHLAND AVE. NEEDHAM. MA 02194

NEECO WILL MATCH ANY ADVERTISED PRICE ON CBM EQUIPMENT.

(617) 449-1760

Telex: 951021

MON-FRI 9:00 - 5:00 MatterCharge and VISA Accepted I

Circle 283 on inquiry card.

BYTE May 1981 259

BYTEWRITER-1

Price Breakthrough from

MICROTEKnc

260 BYTE Miy 1981

Tlw Worid^ First Under $300 80 Column Dot Matrix Printer

WHY DID IT HAPPEN?

We were approached recently by a man with an idea. He is one of the leading American manufacturers of dot matrix print mechanisms. He had observed, as we had, that in recent months certain foreign printer manufacturers were increasing their share of the low-cost printer mari<et at an alarming rate.

He thought there MUST be a way to fight back. And he was right. We've since formed a working alliance with this manufacturer, and have brought our first joint offering to the market.

HOW DID WE MAKE IT POSSIBLE?

We set out to combine his proven low cost print mechanism with the simplest possible control electronics. Advances in single-chip microprocessor technology and price erosion of components during the last year helped to make this long awaited dream come true - a printer that can be sold for less than half the cost of the computer that drives it. A $299 printer.

But cost-effective designs and efficient manufacturing operations weren't enough. Computer retailers can make up to a $250 markup on the foreign models. Could we hold to a $299 list price and give the dealer enough incentive to sell the Bytewriter-1? No way. We had to try a more direct approach.

YOUR BUY DECISION - DEALER OR MAIL ORDER There are some very good reasons to buy your first computer through a dealer. There is a certain amount of hand-holding required when you decide to buy a personal computer. This is one of the main functions of the retail computer store. And most of them perform this function very well.

But why would anyone want to buy add-on equipment through a dealer? If you find a product that has been designed for and tested with your particular computer, you can safely bypass the computer dealer. You can have the best of both worlds. You can save money by buying direct from the manufacturer, and you can be certain that your new device will work when you get it.

We've done extensive testing with the most popular computers - the TRS-80, the Apple II, and the Atari 400 and 800. If you own one of these computers, we guarantee you won't have any interface problems with the Bytewriter-1.

TRS-80 is a trademark of Radio Shacl<, Div. of Tandy Corp. Apple II is a trademark of Apple Computer, Inc. Atari 400 & 800 are trademarks of Atari, Inc. Bytewrlter-1 Is a trademark of Microtek, Inc.

FOUR THINGS YOU SHOULD KNOW BEFORE YOU BUY THIS PRINTER

We don't want any unhappy customers. We'd

like you to know the limitations of our printer, as well as its advantages. There are some differences between the Bytewriter-1 and the higher priced printers you may be looking at:

1) The Bytewriter-1 takes single sheet and roll paper only. No pin feed paper.

2) We've used a 7-wire print head. No fancy lower case descenders.

3) There aren't any software frills in the Bytewriter-1,like VFU controls. However, If your main interest is getting software listings or printing letters, you won't care. And, with a bit of ingenuity, you can provide VFU functions in your own programs.

4) You can't go into a computer store and pick up a Bytewriter-1. They're sold direct only by MICROTEK.

We realize it's unusual to point out the limitations of a product in an ad that promotes it, but we think it's important for mail order buyers to fully understand what they're buying.

The Bytewriter-1 will fill the needs of most people. People who don't see the sense in spending extra money for features they'll never use.

ORDER THE CONFIGURATION THAT'S JUST RIGHT FOR YOU

The Bytewriter-1 is available with an interface cable and complete instructions for use with three of the most popular small computers on the market today, the Apple II, the Atari 400/800, and TRS-80 Models I, II, and III. One of our divisions, MICROTEK PERIPHERALS CORP., can even provide you with the expansion card or module that your computer may require to drive a printer.

CALL OR WRITE TODAY FOR IWIORE INFORMATION.

We have people standing by to answer your questions.

MICROTEKiMx

Microtek, Inc. 9514 Chesapeake Drive San Diego, CA 92123 Tel. 714-278-0633 Outside Calif, call toll free: 800-854-1081 TWX. 910-335-1269

Circle 262 on Inquiry card.

BYTE May 1981 261

BYTELINES

News and Speculation About Personal Computing

Conducted by Sol LIbes

Apple III Emulation Mode: Axlon Inc is working on a project that

will allow an Apple II to run most of the software designed for the Apple III — including the Apple III disk operating system, SOS. The product has its roots in another product recently introduced by Axlon, the Axion 256 Memory System. The unit consists of an interface card and a card cage that contains up to 256 K bytes of memory. There are separate versions for the Atari and Apple 11, and one for the Apple III is in the works. Expressed simply, the unit can exchange 32 K-byte blocks of its memory for the top 32 K bytes in the 48 K machine connected to it.

Special disk-operating-system software included with the unit makes its operation transparent to the user. The hardware/software combination looks to the host computer like a large-capacity disk drive. Program files in the memory of the unit can be run as if they were on floppy disk, and data files can be accessed in both random and serial fashion. There are two advantages to this unit; one, information can be accessed in microseconds (as opposed to milliseconds or longer for floppydisk drives); and two, the increased main-memory space makes both existing and proposed programs that crowd the current 48 K-byte limit more feasible.

The Sunnyvale, Californiabased Axlon is working with Apple Computer to finalize the design of the Apple III emulation hardware/software combination. The proposed unit will include the Axlon 256 Memory System* a^

262 May 1981 ® BYTE PubUcatioiu Inc

special hardware board, special software, and an 80-column adapter for the Apple II.

EeprOM Is Coming:

Several IC designers are predicting that the EEPROM (electrically erasable programmable read-only memory) will replace the ultraviolet-light EPROM within three to four years and may, perhaps, be used as nonvolatile main memory. Several companies are now putting finishing touches on these devices for introduction later this year. For example, Hitachi has announced the HN48016, a 16 K-bit EEPROM (2 K by 8 bits) that is pin-compatible with the popular 2716 UVEPROM. It uses the same voltages, takes 10 ms per byte to program, and can be completely erased with a 1-second pulse. Data retention is claimed to be more than ten years. Intel has a similar device called the 2816. Prices and access times are comparable to their EPROM equivalents.

A^lcrosoft Adds

Graphics Commands To BASIC; Microsoft is offering OEMs who have hardware graphics capability an enhanced version of the popular BASIC-80 interpreter. The added commands will allow you to create lines, boxes, circles, curves, do object painting and relocation, and save all your work. Seven new commands have been added: CIRCLE, PAINT, GETSET, LINE, DRAW, PUT, and PRESET.

Oontlnuing AMSAT OSCAR Activity: AMSAT,

the Radio Amateur Satellite Corporation, has survived the loss of its Phase-IIIA

OSCAR satellite. (See "BYTELINES," September 1980 BYTE, page 166.)

Construction of a new Phase-IIIB satellite is underway in Marburg, West Germany; Budapest, Hungary; and Washington DC. AMSAT has scheduled the satellite's launch for February 24, 1982 on a European Space Agency Arrianebooster flight.

As part of its planned use, the satellite will relay computer data by amateur radio operators in personal-computer networks.

For information on how to join AMSAT and receive Orbit magazine, write to AMSAT, POB 27, Washington DC 20044.

Details On 32-Blt

Microprocessors: Intel released more information on its new 32-bit microprocessor, called the iAPX432. The microprocessor, under development for six years, features an object-oriented architecture that treats highlevel entities as elementary software components that can be easily manipulated. These entities include records, queues, tasks, and collections of procedures.

In its simplest form, the microprocessor consists of two integrated circuits. More processors can be added later to obtain multiprocessing without altering software. It is expected that samples will be available in the fall.

S 100,000 ComputerChess Prise Offered:

Carnegie-Mellon University (CMU) is offering a prize of $100,000 to the first person to develop a computer program that can defeat the world chess champion. Dr Hans Berliner, a computer scientist at CMU and a former world chess champion, heads the competitionrules committee. He feels that the prize may be won by 1990 or sooner, but certainly no later than the year 2000.

Last year a $1000 CMU

prize was won when Jack Gibson, a chess expert, was defeated by Belle, a computer-chess machine developed by Ken Thompson and Dr Joe Condon, researchers at Bell Laboratories, Murray Hill, New Jersey.

AAlnl-Wlnchester Update: Five companies have announced 5-inch Winchester drives. The drives'

storage capacity ranges from 1.8 to 12.3 megabytes (unformatted), and prices vary from $690 to $1600 (500-unit quantity prices). Most suppliers are now shipping evaluation units to OEMs (original equipment manufacturers), with limited production expected by late summer. Don't expect full production until next year.

The five companies which have already announced mini-Winchester hard disks are Shugart Associates, Seagate Technology, Irwin International, Tandon Magnetics, and New World Computer Company. The price leader appears to be Shugart, with its SA602 3.3-megabyte drive at $660. The maximum storage leader is the 12.3-megabyte

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rouo ^- Apple Pascal trademark

3.0) ^ Apple Computers Peorl trademark

CPU Infl Pascal/M, ACT, Trans 86 trodemorks Sorcim CBASIC2 trademark Compiler Systems Magic Wand trademark Small Business Applications Datebook II, Milestone Irodomork Organic Software Ultrosort-ll, FABS trademark Computer Control

ttiolt fotn

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^PP\■

densi>N

Systems Magic Menu, Spell Menu trademarks Ctiorles Merrilt Spellguord trodemork ISA CP/M, "^ie<n UP/U, CP/M-86, PI71-80 trademarks Digital l^eseorcti TRS-80 trademark Tandy Superbrain trademark Intertec

laWi sott-5° Data Systems Copywriter, Copyproot, Diction trademarks Systronlcs Microstat trademark Ecosoft S-Boslc trodemork Topaz

' Programming UCSD trodemork Regents Uniuersity CA WordStar trademark Micro Pro int'i Spellbinder trademark Lexlsoft MCALL, AMCALL trademarks MIcroKlall Services Bosic 80, Fortran-80 trodemorks Microsoft Pascal M/T trademark MT Microsystems Z8C trademark ZIlog NorttiStar trademark NorttiStor Cotnputats baZIC trademark Micro Mike s Prices subject to clionge witliout notice For shipping add $7. per package ColifornIa residents odd tax Terms: Prepoid-otieck, M/C, VISA or In US COD (UPS) Dealer Inquiries invited Prices quoted do not include deoler installation & training

Circle 127 on inquiry card.

BYTE May 1981 263

BYTELIWES

Model 510 from Irwin. It costs $1500, which includes integral tape-cartridge backup.

^Tl Improves The 99/4 Home Computer: Texas Instruments Is determined to make its Tl 99/4 home computer a success. Tl has improved the competitive position of the 99/4 by substantial price cuts and software improvements, the two areas in which the machine fared poorly. The new list price for the console is $649.95, a reduction of $300, and the radio-frequency (RF) modulator's price has been reduced from $75 to $50.

Tl has introduced a software-development system that includes UCSD Pascal and a ROM (read-only memory) module with an assembly-language debugger. The console has been modified and includes dual floppy-disk drives and RS-232C interfaces. Tl has also announced third-party software-incentive programs for software developers. Tl plans to introduce extended BASIC and memory-expansion capabilities in the Tl 99/4. Regrettably, Tl has not seen fit to improve the keyboard or make any substantial hardware improvements other than the addition of memory.

A/iore On DaisyWheel Printers; Daisywheel printers are the most widely used printers for letter-quality hard copy, but the market is undergoing substantial change. Last year, the number of daisywheel-printer manufacturers doubled. More competition meant lower prices and increased performance. The new entries came from Olivetti, Fujitsu, Ricoh, C Itoh, and Pertec. Qume and Diablo still dominate the market, but competitors are

broadening their performance range from the traditional 45 to 55 cps (characters per second) to 15 to 80 cps.

The 45 to 55 cps range is dominated by Qume, an ITT subsidiary with 45°/o of the market, and Diablo, a Xerox subsidiary with 40% of the market. NEC also has a 107o market share, with the other companies dividing the remaining 5%. The prices of these machines should drop about $1000, to $2700 within the next two to three years, and the printer manufacturers will most likely introduce 30 cps versions selling for under $2000. Look for the 30 cps machines by yearend.

Expect a price war between the manufacturers of

the lower-speed 15 to 20 cps printers. Prices may drop to $1200 or less by year-end. Those companies at loggerheads in this marketing war are Ricoh (which supplies Tandy), Olivetti, Pertec (which supplies machines made by Triumph-Adler), and C Itoh.

Fujitsu has already demonstrated an 80 cps daisy-wheel printer. Look for it in computer stores this summer. Qume, Diablo, and NEC are expected to introduce 80 cps machines, and some companies are working on 100 cps machines.

^\da On Microcomputers: At a recent ACM/SIC PLAN-sponsored meeting, TeleSoftware demonstrated the new Ada language on a 16-bit microcomputer. The compiler is 50 K bytes, supports run-time utilities, and produces pseudocode that runs directly on a Western Digital Pascal/Ada Microengine system. TeleSoftware said that the Ada code could be converted to the native code of some other microprocessor by use

of a simple p-code interpreter Cp-code is the machine language executed by the Microengine). Ken Bowles, the developer of UCSD Pascal and founder of TeleSoftware, said the company also intends to provide Ada compilers for 8086-, 68000-, and Z8000-based systems.

Western Digital will manufacture the Pascal/Ada Microengine for $12,750. It will include 128 K bytes of programmable memory, five I/O ports, a 10-slot chassis, video-display terminal, dual floppy-disk drives, and a line printer. The basic system will cost$6210. Western Digital also said that it soon expects to release a hard-disk controller, a cryptographic security module, a distributed multiprogramming operating system, and an X.25 packet-switching and local network product for the processor.

Computer Bulletin Boards Grow In Populate Itys There are over 200 CBBS (computer bulletin board systems) in this country and their number grows weekly. Anyone with a terminal, modem, and telephone can access them. (If you use an Apple computer, they are called ABBS.) Most CBBS and ABBS serve as message centers for computer clubs. Some systems distribute software; for this service, a caller needs a computer with modem-driver software for file transfers.

Other bulletin board systems serve special interests (eg: AMRAD's Blind Service CBBS 703-281-2222, the Family Historians' CBBS 703-978-7561, and Aviators' BBS 916-3934459). For more information on all of these systems and how to access them, call the MAGMEDIA-80 CBBS (415) 573-8768.

H ere Come The Japanese: Expect to see

several Japanese personalcomputer systems in US stores this fall. Most of the systems will compete directly with the Apple II, Commodore PET, and Radio Shack TRS-80. They'll sell for the same price, perhaps slightly less, but offer extra features. NEC (Nippon Electric Company) will market the PC-8001 at the same price as the Apple II. (See "The NEC PC-8001: A New Japanese Personal Computer," by Michael Keith and C P Kocher, January 1981 BYTE, page 72.) Its features will match or exceed the Apple's. Matsushita (known in America as Quasar and Panasonic) and Sharp are also expected to have their systems on dealer shelves this fall. The Z80-based Sharp system is already on sale in England. One English distributor has already adapted CP/M for it.

Shopping Via Compu^

er; Comparison retail shopping by home computer appears to be the wave of the future. One of the first computerized retailers is CompU-Card of Stamford, Connecticut. It claims to have 1.5 million members, of which 5000 already have computer I/O capability. To become a member it costs $18 per year, or $9 if you come under a group plan. To access the service's base of more than 30,000 items, you call it either via a toll-free telephone number or a twoway cable TV hookup. Comp-U-Card presents product specifications, price, and delivery charges. You can order any item at a typical savings of 20 to 40% or just use the service to compare prices.

^^ata-Base Systems Ex

264 May WSl © BYTE Publications Inc

The VP-111 hobby computer: Start programming for only ^99.

^99.

New! VP-111 Microcomputer.... Assembled* and t^ted.

Features:

• RCA 1802 Microprocessor.

• 1K Bytes static RAM. Expandable on-board to 4K. Expandable to 32K Bytes total.

• 512 Byte ROM operating system.

• CHlP-8 interpretive language or machine language programmabia

• Hexidecimal keypad.

• Audio tone generator.

• Single 5-volt operation.

• Video output to monitor or modulator.

• Cassette interface—100 Bytes/sec.

• Instruction Manual with 5 video game listings, schematics, CHIP-8, much more! Ideal for low-cost control applications. Expandable to full VP-711 capability with VP-114Kit.

•User need only connect cables (included), a 5-volt power supply and speaker.

!199.

New low price! VP-711,only.... Completely assembled and tested.

All the features of the VP-111 plus:

• A total of 2K Bytes static RAM.

• Power supply.

• 8 Bit input port.

• 8 Bit output port.

• I/O port connector.

• System expansion connector.

• Built-in speaker.

• Plastic cover.

Three comprehensive manuals:

• Instruction Manual—20 video game listings, schematics, much more.

• User's Guide—operating instructions and CHIP-8 for the beginner.

• RCA 1802 User's Manual (MPM

201B)—complete 1802 reference guide.

RCil

Add computer power a board at a time.

With easy-to-buy options, the versatile RCA hobby computer means even more excitement. More challenges in graphics, games and control functions. For everyone, from youngsterto serious hobbyist.

Built around an RCA COSMAC microprocessor, our hobby computer is easy

to program and operate. Powerful CHIP-8 interpretive language gets you into programming the first evening. Complete documentation provided.

Send the coupon now...

Complete the coupon below and mail to: RCA Microcomputer Customer Service, New Holland Ave., Lancaster, PA 17604.

Or call toll free (800) 233-0094

to place your Master Charge or VISA credit card order In Pennsylvania, call (717) 397-7661, extension 3179.

Please send me the items indicated.

□ VP-111 New low cost Microcomputer

(See description above) $ 99

□ VP-114 Expansion Kit for VP-111 -Includes

3K RAM, I /O Port and connectors $ 76

□ VP-711 The original VIP Microcomputer

(See description above) $199

O VP-44 RAM On-Board Expansion Kit—Four 2114 RAM ICS. Expands VP-711 memory to 4K Bytes $36

□ VP-590 Color Board—Adds color. Four

background and eigtit

foreground colors $ 69

□ VP-595 Simple Sound Board—Provides

256 programmable frequencies. For simple music or sound effects. Includes speaker $ 30

□ VP-5S0 Super Sound Board—Turns

VP-111 /711 into a music synthesizer! Two independent sound channels. Outputs to audio $ 49

□ VP-551 4-Channel Super Sound—Includes

VP-576 and demo cassette. Requires VP-550 and 4K RAM $ 74

D VP-570 Memory Expansion Board—

Plug-in 4K RAM memory $ 95

O VP^SSO Auxiliary Keypad—Adds two-player interactive capability. Connects to VP-590 or VP-585 $ 20

D VP-58S Keypad Interface Board—Interfaces two VP-580 Auxiliary Keypads to VP-111/711 $ 15

□ VP-560 EPROM Board—Interfaces two

2716 EPROMS to VP-111/711 .. $34

□ VP-565 EPROM Programmer Board

Programs 2716 EPROMs. □ VP.

With software $ 99

□ VP-57S Expansion Board—Provides 4

buffered and one unbuffered □ VPexpansion sockets $ 59

□ VP-576 Two-Board Expander—Allows □ VP

use of 2 Accessory Boards in either

I /O or Expansion Socket $ 20 □ vP'

□ VP-700 Tiny BASIC ROM Board—BASIC

code stored in 4K of ROM $ 39 □ vp.

D VP-701 Floating point BASIC for

VP-711 on cassette. Requires 16K □ vp.

Bytes RAM (avail. 7/80) $ 49

□ VP-710 Game Manual—Listing for 16 p vp.

exciting games $ 10

□ VP-720 Game Manual-ll—More games .. $ IS □ vp.

□ VP

Keyboards & Terminals ■601 Keyboard—128-character ASCII

encoded alphanumeric 8-bit parallel

output $ 69

■606 Keyboard—Same as VP-601.

Asynchronous serial output $ 99

■611 Keyboard—Same as VP-601 plus

16-key numeric keypad $ 89

■616 Keyboard—Same as VP-606 plus

16-key numeric keypad $119

■620 Cable-Connects VP-601 /611 to

VP-111/711 $ 20

■623 Cable—Untermlnated for

VP-601 /611 $ 20

■626 Connector—Male "D" mates to

VP-606/616 $ 7

3301 Interactive Data Terminal

■3303 Interactive Data Terminal

with built-in RF output

Enclosed is $ for items checked plus shipping & handling charge of $3.00.

Add your state and local taxes $ Total enclosed $

I enclose □ check or □ money order Or charge my □ VISA □ Master Charge. Credit card account No.

Master Charge Interbank No.

Signature (required for credit orders);

Name (please type or print):

Street address:

State & Zip:

Expiration date.

. Telephone:( ).

-City:.

Make checks payable to RCA Corp. Prices and specifications are subject to change without notice.

Circle 351 on inquiry card.

B YTELINES _

pandlngi The need to access reference material has

become much easier because of computerized database distributors. For example, a lawyer can access the Nexis system from Mead Data Central, 200 Park Ave, New York NY 10017, for a special keyed^vord newssearch service. The cost is $1 to $1.50 per minute, plus a $300 monthly charge. The initial sign-up charge is $425. There are many lower-cost data-base services catering to the special needs of various professionals.

For information on database systems, consult the Directory of On-L'me Data Bases, published by Cuadra Associates, 1523 Sixth St, Suite 12, Santa Monica CA 90401. The price is $60 per year (four issues).

^■omputer Makers To Market Private Software: If you develop software for the HP-85 desk-top

system in your spare time, Hewlett-Packard has a plan for marketing it. HewlettPackard will pay a royalty for the software and offer to sell you a system at a discount. Burroughs has a similar plan.

^Jm On Robotics Shopping Spree: GM has

ordered 25 robots for its

transmission-machining lines at its Warren, Michigan, facility. This is the largest undertaking of its kind in the automotive industry. The robots will cost almost $2 million. GM plans to buy as many as 1800 programmable robots between now and 1984.

In a related development, GM will use laser checking devices on its J-car-body assembly lines; the devices will check 20 to 30 points on each car for proper body fit and panel alignment. There

will be no contact with the auto during this checking procedure.

^^T&T To Enter Computer Market: In a landmark decision, the FCC will allow AT&T (American Telephone & Telegraph) to enter the computer business. The decision requires AT&T to set up a separate subsidiary to offer terminals and computer-enhanced services. Industry pundits speculate that AT&T will position itself to capitalize on the marriage of the telephone and computer technologies..

u.

'sed Word-Processor Market Burgeoning: You

can save quite a bit of money by buying a used word processor. IBM, Xerox, Lanier, and Vydec systems are becoming available as companies upgrade to newer, more powerful machines. In Minneapolis, Word Systems Inc specializes in selling used wordprocessor systems, although they are also available through many other dealers.

Extra-Life Printer Ribbons: Replacing printer ribbons is expensive. Here's how to revive worn-out closed-loop ribbons housed in plastic cases: carefully pry open the case without disturbing the ribbon. Spray the ribbon lightly (don't overspray) with an all-purpose lubricant such as WD-40, close the case, and let it stand overnight. The lubricant causes the ink from the moist unused portions of the ribbon to flow down into the dry areas of the ribbon. This renewal process can usually be repeated several times before the ribbon Is completely exhausted.

I^andom News Bits:

United States Robots, Con

shocken, -Pennsylvania, claims to have developed a five-jointed robot arm using seven microprocessors—one for each joint, one for math calculations, and one for overall coordination. The microprocessors do multiprocessing on a shared bus and memory system. ...Toshiba and Hitachi have demonstrated "pocketbook TVs" that typically use 120- by 160-element LCDs (liquidcrystal displays). Matsushita and Hitachi reportedly will introduce products next year using these displays. ...Interested in learning more about possible health hazards associated with CRT (cathode-ray tube) terminals? Then you should get a copy of the 16-page pamphlet entitled Health Protection for Operators of DCTs/CRTs. It's published by the New York Committee for Occupational Safety and Health, 32 Union Sq, Rm 404, New York NY 10003 ($1 for individuals; $3 for institutions).

I^andom Rumors:

Apple Computer may put off its plans to build 5-inch Winchester-disk drives for the Apple III and the rumored Apple IV. Apple has reportedly inked a contract for 10,000 six-megabyte ST-506 drives from Seagate Technology. Apple still plans to produce a hard-disk drive for introduction next year. ...It is rumored that Digital Equipment Corporation has developed a single-integratedcircuit version of the PDP-11 and that it exists in prototype form. No production plans have as yet been established. ...There is a lot of talk circulating that Xerox will soon release a version of the Smalltalk programming language and a complete book describing it. Most likely it will be released to

universities who presently have the Xerox Alto system

(an experimental personal computer). ...Electronic News recently reported that IBM and Tandy were holding discussions on the possibility of IBM 3103 video terminals being sold through Radio Shack stores. ...According to a report issued by International Resource Development Inc (IRD) in Norwalk, Connecticut, IBM, Xerox, and Matsushita will introduce typewriters with voice input by 1983. IRD predicts that the typewriters will correctly recognize 93% of "typical business English as spoken by the average executive," and that the unit will have a video screen that displays the spoken words. Corrections and changes can be made on the screen....

MAIL: I receive a large number of letters each month as a result of this column. If you write to me and wish a response, please include a self-addressed, stamped envelope.

Sol LIbes POB 1192

Mountainside NJ 07081

266 May 1961 © BYTE PubUcations Inc

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for a given hardware configuration.

MICROSOFT BASIC-86

ITS THE STANDARD — This BASIC is essentially

identical to version 5 of Microsoft's BASIC interpreter, the accepted standard with widely available application programs. Programs distributed in CP/M® format are easily converted to the 86-DOS system. (CP/M is a registered trademark of Digital Research.)

IT'S FAST — It is two to seven times faster than BASIC80 on a 4 Mhz. Z-80, depending upon application.

BREAKING THE 64K BARRIER — How many of you can run an extended disk BASIC and see the message "63309 Bytes free" when It signs on?

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Circle 363 on Inquiry card.

BYTE Miy 1981 267

Not for sale in any bookstore! Not available at any price! The new GDnsumer Information Catalog! It's the free booklet that lists over 2(X) helpfial Federal publications; more than half, free. On topics like home repairs. Money management.

Nutrition. Information that coiald help you to a better way of life. To get your free copy, just write:

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GeneraJ Services Administration 268 May 1981 © BYTE Publkalioiu Inc

Letters

Continued from page 20:

Resistible Puzzle

John Moore revived the earlierpublished problem of creating a network with resistance of 355/113 (a very close approximation to tt) with a minimum number of unit-valued resistors. (See the January 1981 BYTE, page 16.) He improved greatly on W Lloyd Milligan's 26-unit solution (see the August 1980 BYTE, page 20) by presenting two 18-unit solutions and asking if anyone could find a solution with 17 or fewer resistors.

By abandoning their continued-fraction method in favor of one based on Diophantine equations (those having positive, non-zero integer solutions), I was able to come up with two different 15-unit solutions. (See figures la and lb.)

I believe these two to be minimal, and essentially the only minimal solutions (ie: except for other solutions created by trivial transpositions of series and parallel elements in one of these resistors) within

the class of networks examined by this method and by the continued-fraction method (ie: all simple series-parallel networks).

But there are many more ways to connect a handful of resistors than just in simple series-parallel networks I

I looked for a solution with a bridge as a part of the total network. With the help of a TI-58 programmable calculator, I was able to find a 14-unit solution. (See figures 2 and 3 on page 270.)

Of course, with 12 or 13 resbtances to coimect together in an arbitrary fashion, much more complicated figures than bridges are possible. Unfortunately, the calculation of resulting network impedance, and the searching through the various configurations, becomes correspondingly complex. I suspect that the 14-unit solution can be improved upon.

David F Smith 3033 Turk Blvd, )jl3 San Francisco CA 94118

(la)

(lb)

Figure l: Two 15-unit networks with Z—

113

#3

The Byte Covers shown at left are available as Collector Edition Prints. Each full color print is:

• 11" X 14" including a IVa" border.

• Part of an edition stiictiy iimited to oniy 100 prints.

• Personally Inspected, signed and numbered by the artist, Robert Tinney.

• Accompanied by a Certificate of Authenticity.

• Carefully packed and shipped first class.

• Priced at $20, plus $3 ($6 overseas) for postage and handling. If Set 1-4 or Set 5-8 is ordered, the price for all 4 prints is only $70.

To order, use the coupon below. Visa or MasterCharge orders may call Toll Free.

Please send me the following Collector Edition Byte Covers and Certificates of Authenticity.

Qty. Cover Amount

#1-7 Bridges of Konlgsberg $20

#2-Fun and Games $20

#3-Homebrew $20

#4-Software Mirage $20

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Mail this coupon to:

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Letters

Figure 2: A 14-unit network with Z =

355 113

355 mV

< E

129 mV

58 mV

wv

13mA

45mV

OmV

Figure 3: Voltages and currents in the 14-umt network with 355 mV across it.

Easier Communication In Two Directions

Mark R Titchener's article "Communications in Two Directions" (June 1980 BYTE, page 96) presents a circuit to communicate bidirectionally on a single line; however, it requires too many components. An easier way to do it is shown in figure 4. This circuit will work for both analog and digital signals. Using standard op-amp theory, it is easily shown that V4 = V2 and V3 = VI. Line impedance can

be compensated for by making RO variable.

R Gupta

Electrical Engineering University of Auckland Private Bas, Auckland New Zealand

Smart Wheelchair Project

Steve Ciarcia's article "Home in on the

-ii

V

Figure 4

-e V3

Range! An Ultrasonic Ranging System" (November 1980 BYTE, page 32) was excellent. I would, however, like to make BYTE readers aware of another project that has incorporated the Polaroid Ultrasonic Ranging technology. The project was funded by the Veterans Administration Rehabilitative Engineering Research and Development Center of Palo Alto, California. The participants, Karen Altman, Rick Epstein, Leslie Gerding, Wayne Ledger, and Dave Parker, were graduate students last year at Stanford Mechanical Engineering.

The objective was to design, develop, and successfully fabricate a "smart" electronic wheelchair. Its construction included ten ultrasonic sensors, eight of which were used to detect approaching obstacles or the presence of a wall on either side of the chair. The remaining sensors were focused on the user's head from two angles. .

The chair has many modes of operation: the most important is the headcontrol mode. Here, the user directs the movements of the chair by head motions. To move the chair forward, the user posi

270

May 1981 © BYTE Publications Inc

&COMPUSnR USERS'GROUP

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Since our first ad in March 1981, we have been contacted from as far away as South America, Europe, Australia, and Indonesia. Super★ Star International is becoming a world-wide famiiy whose members wili enjoy the benefits of a wide range of hardware and

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Our full color, monthly magazine will print a free program in every issue—programs like an appointment calendar and personal finance record keeping. You'll also find technical Information, tips for beginners, special business uses, equipment reviews, and the Intertec Story—the people. Ideas, and machines behind your computer.

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Laf tort

tions his or her head toward the front of the chair. Similar operations control the three remaining directions. In effect, the user's head is a proportional-control joystick. One can readily see that this type of noncontacting control would be helpful for people who have no usable arm function.

In operation, the front-facing ultrasound sensors detect the presence of obstacles in the chair's path. When such an obstacle comes within a predetermined distance, the chair automatically slows and stops before running into it. If the

"obstacle" moves away, the chair will follow at a fixed distance.

Side sensors serve to detect walls. A mode to "follow that wall" enables a chair to travel parallel to the chosen wall at a fixed distance. Open doorways are detected and passed over, but a discontinuity of more than a few feet disables the wall-following mode and waits for further commands from the user.

A "cruise control" mode does not use any additional sensors, but instead relies on wheel-speed data obtained from two optical shaft encoders. Once in this mode,

the chair proceeds at a constant speed and heading despite changes in terrain.

A final mode allows the head to be moved without affecting the chair.

The user initializes the system to the range of his or her head motion by means of a "training" program that instructs the user to center the head, to move it to the left or right, and forward or backward. The program uses this information to calibrate the position/speed algorithm as well as set up a dead band around the user's rest position.

The hardware presently consists of a Z80 microprocessor, 64 K bytes of memory, and an external disk-drive system. Once the program is loaded, the disk is disconnected and the user drives off. The software executive is written in BASIC, with a majority of the actual real-tjipe program coded in machine language aj\d as arithmetic function calls. The listing consumes 40 pages.

The current construction phase will shrink the initial hardware and software configuration by one-third. A final design will capture the features on a single printed-circuit board.

The approach taken in pursuit of the interface between the ultrasound sensors and the microprocessor is considerably different from the method described in Steve's article. Since the Polaroid kits were not available at the time of construction, several new cameras were sacrificed to acquire the parts required. In addition, the computer interface was done not at the EDB level, but at the custom ultrasound board level. To perform a ranging, the computer generates a transmit request pulse via a convenient parallel output bit. The output from the board is then interrogated to start a software timii\g loop that is terminated by the received echo signal. The number of times the loop is performed gives a fairly precise measure of the range. Dividing this value by an appropriate factor will yield the range in whatever units are required. In the course of the project, a resolution of about a quarter of an inch was obtained over distances ranging from 9 inches to 20 feet (depending on surface characteristics).

Additional information about this ongoing project can be obtained by writing me at the address below.

David L Jaffe

Palo Alto VA Medical Center Rehabilitative Engineering Research and

Development Center 3801 Miranda (153) Palo Alto CA 94304B

Waiting On Delivery of A DEC LA120?

Avoid the hassle by upgrading your LA36 for 1200 baud operation with a DS120 Terminal Controller.

■ The Datasouth DS120 gives your DECwriter® 11 the high speed printing and versatile performance features of the DECwriter® 11! at only a fraction of the cost. The DS120 is a plug compatible replacement for your LA36 logic board which can be Installed in minutes. Standard features include:

•165 cps bidirectional printing •Horizontal & Vertical Tabs •Page Length Selection •110-4800 baud operation • 1000 character print bufter •X on, X off protocol •Self Test

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Over 4000 DS120 units are now being used by customers ranging from the Fortune 500 to personal computing enthusiasts. In numerous installations, entire networks of terminals have been upgraded to take advantage of today's higher speed data communications services. LSI microprocessor electronics and strict quality control ensure dependable performance for years to come. When service is

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272 May 1981 © BYTE Publlcationi Inc

Circle 118 on Inquiry card.

d&ASE II vs. the Bilge Pumps.

by Hal Paxvluk

V^fe all know that bilge pumps suck.

And by now, we've found out—the hard way—that a lot of software seems to work the same way.

So I got pretty excited when I ran across dB ASE II, an assembly-language relational Database Management System for CP/M. It works! And even a rank beginner like myself got it up and nmning the first time I sat down with it.

If you're looking for software to deal with your data, too, here are some tips that will help:

Tip #1: Database A\2d\agement vs. File Handling:

Any list or collection of data is, loosely, a data base, but most of those "data base management" articles in the buzzbooks are really about file handling programs for specific applications. A real Database Management System gives you data and program independence (no reprogramming when data changes), eliminates data duplication and makes it easy to turn data into information.

Tip #2: Assembly Language vs. BASIC:

This one's easy: if you're setting up a DBMS, you're going to be doing a lot of sorting, and Basic sorts are s-l-o-w. Run a benchmark on a Basic system like S*-IV against a relational DBMS like dBASE II and youll see what I mean. (But watch it: I've also seen one extremely slow assembly-language file management system.)

Tip #3: Relational vs. Hierarchal & Network DBMS.

CODASYL-like hierarchal and network systems, aroxmd since the 1960's, are being phased out on the big machines so why get stuck with an old-fashioned system for your micro? A relational DBMS like dBASE II eliminates the predefined sets, pointers and complex data structures of a CODASYL-type DBMS. And you don't need to be a programmer to use it.

dBASE n vs. everj^thing else.

dBASE II really impressed me. Written in assembly language (with no need for a host language), it handles up to 65,000 records (up to 32 fields and 1000 bytes each), stores numeric data as packed strings so there are no roxmdoff errors, has a superfast multiple-key sort, and supports ISAM based on B* trees.

You can use it interactively with English-like commands (DISPLAY 10 PRODUCTS), or program it (so when you've set up the formats, your secretary can do the work). Its report generator and userdefinable full screen operations mean that you can even use your existing forms.

And if all this makes your mouth water, but you've already got all your data on a disk, that's okay: dBASE II reads your ASCII files and adds the data to its own database.

Right now, I'm using dBASE II with my word processor for budgeting, scheduling and preparing reports for my clients.

Next come job costing, time billing and accoimting.

An Unheaird-of Money-Back Guarantee.

dBASE II is the first software I've seen with a full money-back guarantee.

To check it out, just send $700 (plus tax in California) to Ashton-Tate, 3600 Wilshire Blvd., Suite 1510, Los Angeles, CA 90010. (213) 666-4409. Test dBASE II doing your jobs on your computer for 30 days. If, for some strange reason, you don't want to keep it, send it back and they'll refund your money.

No questions asked.

They know you don't need your bilge pumped.

Ashton-Tate

©Ashton-Tate 1980

Circle 34 on Inquiry card.

BYTE May 1981 273

GaUei^ of CP/M MasZerworks

DIAGNOSTICS I: A system diagnostic package.

Tests:

Memory • CPU (8080/8085/280) • Terminal • Disk • Printer To our knowledge the CPU test is the first of its kind anywhere. Diagnostics I can help you find problems before they become serious. A good set or diagnostic routines are a must in any program library. Minimal requirements: 32K CP/M. Supplied with complete user manual: $75.00 Manual alone: $15.00

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Diagnostics II provides the next level in system maintenance.

Requires: 32K CP/M

Price: $100.00 Manual only: S15.00

4

SYSTEM MAINTENANCE

1^

SUPER-M-LIST: A complete, easy to use mailing list program package. Allows for two names, two addresses, city, state, zip and a three digit code field tor added flexibility. Super-M-List can sort on any field and produce mailing labels direct to printer or disk file for later printing or use by other programs. Super-M-List Is the perfect companion to TFS. Handles 1981 Zip Codeal Requires: 48K CP/M

Supplied with complete user manual: $75,00 manual alone: $10.00

TFS-Text Formatting System: An extremely powerful formatter. More than 50 commands. Supports all major features including:

• left & right margin justilication • user defined macros

• dynamic insertion from disk file • underlining and backspace TFS lets you make multiple copies of any text. For example: Personalized form letters complete with name, address & other insertions from a disk file. Text is not limited to the size of RAM making TFS perfect for reports or any big job. Text is entered using CP/M standard editor or most any CP/M compatible editor. Requires: 24K CP/M

Supplied with extensive user manual: $85,00 manual alone: $20.00 Source to TFS in 8080 assembler (can be assembled using standard CP/M assembler) plus user manual: $250.00.

TEXT PROCESSING ^

* t t t t ********* * *■ iTAA^j

SSS FORTRAN: The SSS FORTRAN compiler cs lasl. eflicienl. and complete (lull 1966 ANSI standard witti extensions). The RATFOR compiler compiles into FORTRAN allowing the user to write structured code while retaining the benefits of FORTRAN. The FORTRAf^l supports many advanced features not found in less complete implementations, including: complex arithmetic, character variables, and functions. Complete sequencial and random disk I/O are supported, SSS FORTRAN will compile up to 600 lines per minulel Recursive subroutines with static variables are supported. ROMable ".COM" files may be generated. SSS RATFOR allows the use of contemporary loop control and structured programming techniques. SSS RATFOR is similar to FORTRAN 77 in thai it supports such things as:

' REPEAT . UNTIL • WHILE • IF...THEN„.ELSE

SSS RATFOR is supplied with source code in FORTRAN and RATFOR. System Requirements & Prices: SSS FORTRAN requires a 32K CP/M system.

SSS FORTRAN with RATFOR: J325,00 Documentation alone. $25.00

SS FORTRAN alone: $250.00 RATFOR alone: $100.00 (RATFOR sold only with valid SSS FORTRAN license)

STACKWORK'S FORTH: A full, extended Forth interpreter/compiler produces COfvlPACT. ROMABLE code. As fast as compiled FORTRAN, as easy to use as interactive BASIC.

SELF COMPILING: Includes every line of source code necessary to recompile itself.

EXTENSIBLE: Add functions at will. Z8a or 8080 ASSEMBLER included. Single license, OEM licensino available. Please specify CPU type: Z80 or 8080 Supplied with extensive user manual and tutorial: $17S.OO Documentation alone: $25.00

'TINY' PASCAL II: We still call it Tiny' but it's bigger and belter than ever! This is the famous Chung-Yuen 'Tiny' Pascal with more features added. Features include:

• recursive procedures/functions • integer arithmetic • CASE

• FOR (loop) . sequential disl< I/O • 1 dimensional arrays

• IF...THEN...ELSE • WHILE . PEAK & POKE

• READ & WRITE • REPEAT...UNTIL • more

'Tiny' Pascal is fast. Programs execute up to ten times faster than simitar BASIC programs. SOURCE TOOl We still distribute source, In 'Tiny' Pascal, on each discette sold. You can even recompile the compiler, add features or just gain in. sight into compiler construction.

Requires: 36K CP/M. Supplied with complete user manual and source on discette: $85.00. Manual alone: $10.00

PROORAMMINQ LANGUAGES I

UTILITIES I: A collection of programs that you will find useful and maybe even necessary in your dally worl< (we didl).

Includes:

GREP: Searches files for a specified string SORT: in core sort of variable length records CMP: Compare two flies for equality PRINT: Formatted listings to printer PQ: Lists files to CRT a page at a time

.., plus more ,,,

Requires: 24K CP/M

Supplied with manual on discette; $60.00

UTILITIES II: Many new programs not available elsewhere. Includes these "file" ulilitles:

DIFF: Source comparitor

PR: Powerful multicolumn output formatter

DC: Desk calculator RPL: Substitute strings in files

... plus more...

Requires: 24K CP/M $60.00 Supplied with manual on discette

UTILITIES

4

NOW!!

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TERM: A complete intercommunications package for linking your computer to other computers. Link either lo other CP/M computers or to large timesharing systems. TERM is comparable to other systems but costs less, delivers more and source is provided on discette! With TERM you can send and receive ASCII and Hex files (COM too. with included convertion program) with any other real time communication between users on separate systems as well as acting as timesharing terminal.

• Engage/disengage printer • errorchecking and auto retry

• terminal mode for timesharing between systems

• conversational mode • send tiles • receive tiles Requires: 32K CP/M

Supplied wilh user manual and 8080 source code: S150.00 Manual alone: $15.00

VNTERCOMPUTER COMMUNICATIONS^

ANALIZA: An amazingly accurate simulation of a session with a psychiatrist. Better than the famous "ELIZA" program. Enlightening as well as fun. An excellent example of Artificial Intelligence. Requires: 48K CP/M, CBAStC2 Cost: $35.00

^i"!:!!!::!"?! ENTERTAtNMENT ^ilJ^

Z8000.CROSSASSEMBLER:Supports; full Z8000 syntax, segmented and unsegmented mode, full 32-bit arithmetic, hex output, listing output, "downloader". Requires: 56K CP/M $500.00 1 year maintenance $300.00 manual alone S 50.00

ZBOOOtoo!

ENCODE/DECODE: A complete software security system for CP/M. Encode/Decode is a sophisticated coding program package which transforms data stored on disk into coded text which is completely unrecognizable. Encode/Decode supports muiiipie security levels and passwords A user defined combination (One billion possible) is used to code and decode a file. Uses are unlimiied. Below are a few examples:

■ databases • payroll files • programs • tax records Encode/Decode is available in two versions:

Encode/Decode I provides a level of security suitable for normal use. Encode/Decode II provides enhanced security for the most demanding needs.

Encode/Decode t: SSO.OO Encode/Decode II: $100.00 manual alone: $15.00

On line "Help" system provided with every program package.

SuperSoft

First in Software Technology

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SuperSoft's Masterpiece^^ of the Month

stack Work's

A full, extended FORTH interpreter/compiler produces COMPACT. ROM ABLE code. As hst as compiled FORTRAN, as easy to use as interactive BASIC.

SELF COMPILING

Includes every line of source code nepessary to recompile

itself.

EXTENSIBLE

Add functions at will.

CP/M* COMPATIBLE

Z80 & 8080 ASSEMBLERS included

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Supplied with extensive user manual and tutorial: $175.00

Documentation alone: $25.00

Please specify CPU type. Z80or8080

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CP/M Formats:

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Technical Hot Line: (217) 359-2691 (answered only when technician is available)

SuperSoft

First in Software Technology

*CP/M registered trademark Digital Research

StackWork s FORTH is the copyright of StackWorks. 321 E Kirkwood Bloomington. Indiana 47401

BYTE May 1981 275

KILL

SURGES

LIKE

LIGHTNING!

AC power line surges are destructive, can cost you money, and can't be prevented. But you can stop them from reaching your sensitive electronic equipment with a Surge Sentry.

Surge Sentry acts in picoseconds to dissipate up to a 1,000,000 W, 100/Li second surge. Triggers at 10% above nominal peak voltage. Works in parallel with the power line. Is easy to install for immediate protection. No complicated wiring or special tools required.

Several different models to choose from, including an OEM version. Call or write todayfor afree brochure.

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DEALER INQUIRIES INVITED 276 Miy i«ai © BYTE Pubiicationi inc Circle 345 on Inquiry card.

Texi coiitimied from page 228:

My application required that I code the 10 decimal digits (0 thru 9). I borrowed the 7-bit-per-digit bar code used ir\ the UPC (Universal Product Code) to represent those digits. [JVofe that UPC bar codes, as shown in figure 1, have a different appearance from PAPERBYTE® and other bar-code formats....GVJ] Each of the identifiers that is generated consists of 6 digits, thereby allowing the printer to operate close to the left margin. This was a distinct advantage for my application. The dot-backspacing feature of the printer reduces the dotposition counter by the amount the user specifies, returns the carriage to the left margin, and then back to the new position indicated by the pointer. Because of this method of printing, the time required to print a line increases disproportionately with its length. Thus, short lines are desirable.

The following procedure was used to generate bar codes with the Centronics 737:

• Set the proportional-spacing mode on the printer by issuing the command:

LPRINT CHR$(27); CHR$(17);

This can be done either in, or before running the program, but I suggest doing it in the program to avoid problems that arise in the monospacing mode.

• Read the character codes into a binary array.

• Use the INKEY$ function to enter a character to be printed in bar code. Use the entered value to retrieve the binary code for the character from the array. The Is and Os are values of the variable J, and are used as follows in the LPRINT statement:

LPRINT CHR$(92 * J + 32);

If J = l, then CHR$(124) causes a bar to be printed. If J=0, then CHR$(32) results in a blank space. •Backspace to the dot position immediately following the one just printed, by issuing the following printer command:

LPRINT CHR$(08); CHR$(4); In my application, I placed equivalent Arabic numerals

llllllilllll

800218 llllllilllll

824009

Figure 1: Bar codes generated by a Centronics 737 dot-matrix printer and a TRS-80 computer, using the program in listing 1. The program also prints the equivalent Arabic numerals under the code.

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DISTRIBUTOR INQUIRIES INVITED

DIPjnc.

745 Atlantic Avenue* Boston, MA 02111 • (617) 482-4214

"High-Quotient of performance to cost. *OEM quantity 500

Circle 130 on inquiry card.

BYTE May 1981 277

Using new tools for learning

A prominent MIT educator challenges the conventional approach to computer-assisted learning—one in which computers program children—and demonstrates how children should program the ccimputers, mastering through personal experience the "powerful ideas" that open the doors of mathematics and science. "A revolutionary book... required reading for anyone with an interest in computers, children, education, or the future."

—80 Microcomputing

"Changes the learning experience from a matter of discipline into one of discovery and excitement."

—Marvin Minsky, MIT

MIIMDSTORMS

PDWEFFIL OEAS

SEYMOUR PARERT

Illustrated, $12.95

From the publishers of...

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ARTIFICIAL INTELLIGENCE AND NATURAL MAN

Margaret Boden. This classic analysis of the processes of computer problem-solving is "accurate, articulate, common-sensical,

and entertaining!'

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THE SYSTEMS APPROACH AND ITS ENEMIES

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BASIC BOOKS, INC.

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im

Listing 1: Bar-code generator. The program, written for the Radio Shack TRS-80 with Level II BASIC, generates bar codes for the decimal digits 0 thru 9 on a Centronics 737 printer.

in DIM E!(10,7)

30 ' LOAD THE BINARY ARRAY

in '

SO FORI=OT09:FORJ=lT07{READB<I,J)5NEXTJtNEXTI

<sn '

70 ' SET THE PROPORTIONAL SPACING MODE ON THE PRINTER

an '

9 0 LPRINTCHR*<27>JCHR*<17)}

I 00 '

II n ' BETCIN SIX-DIGIT INPUT LOOP

17.0 '

1,30 F0RN=1.T0A 110 '

150 ' STROBE KEYBOARD FOR AN INPUT DIGIT

1 AO '

17n Y»=INKEYtMFYf=""THEN170 ELSEI=yAL<Y*) SA»(N)=Y*

180 '

19n ' RETRieyE binary code for the digit AND PRINT Znn ' THE BAR CODE REPRERFNTATION FDR IT.

2in '

27 0 FOR K=lTD7:,,h=E::(T,K)

73 0 LPRINTCHR»(97>«J + 37) ;CHR*( OB) ;CHR»(1> J tNEXTKtNEXTN

710 '

750 ' PRINT THE ARABIC NUMERALS

260 '

270 LPRINT" ":forn=itoi5:lprinta»(N)}:nextn

700 '

79 0 ' BINARY CODE FOR DIGITS 0-9

3 (1 0 '

310 DATA 0,0,0,1,1,0,1

370 DATA 0,0,1,1,0,0,1

330 DATA 0,0,1,0,0,1.1

310 DATA 0,1,1,1.1,0,1

350 DATA 0,1,0,0,0,1,1

3A0 DATA 0,1,1,0,0,0,1

370 DATA 0,1,0,1,1,1,1

380 DATA 0,1,1,1,0,1,1

390 DATA 0,1,1.0,1,1,1

100 DATA 0,0,0,1,0,1,1 110 END

after the 6-digit bar code to allow a quick check of the coded identifier. An example of bar codes generated with the Centronics 737 appears in figure 1.

The program in listing 1 was written for the Radio Shack TRS-80 using Level II BASIC. This is only a sample program that can be modified to suit your taste, but it demonstrates how you can generate bar codes on a lowcost printer. ■

BYTE'S Bits

Chess Challenger Upgrade

Fidelity Electronics Ltd has announced a free upgrading service for certain units of its Chess Challenger Electronic Game, Model CCX. The service is available only for units with serial numbers from 150871 to 174517.

If you have a vmit with a serial number in this range.

send a postcard with your name, address, and the serial number of your Chess Challenger to:

Fidelity Electronics Ltd Customer Service Dept 8800 NW 36th St Miami FL 33178.

You will receive notification if the unit requires the upgrading modification. ■

278 May 1981 © BYTE PubUcaUons Inc

STATE OF THE ART MEMORY SYSTEMS

B12KB SINGLE BOARD MULTIBUS® MEMORY

State of the Art Multibus Memory Design. First to Offer 512KB on One Board.

The CI-8086 module is compatible with both 8 or 16 bit Multibus Systems.

PARITY — The CI-8086 generates and checks even parity with selectable interrupt on parity error.

FAST ACCESS AND CYCLE TIME — Data access is 270 NSEC and cycle time is 37S NSEC.

16 MEGA BYTE ADDRESSING — The memory is eddressable in 16K increments up to 16 mega bytes.

LOW POWER CONSUMPTION — Total power consumption is under 8 watts.

SINGLE QTY. PRICE: 128Kx9 SI350. 512Kx9 S299S.

2S6KB LSI 11/23® SINGLE DUAL WIDTH BOARD

The First and Only 256KB Memory on a Single Dual Board.

4 MEGABYTE ADDRESS FIELD — Most memories available for the DEC POP 11 /23 are only addressable to 256K bytes (18 address lines). The CI-1123 is addressable to 4 mega bytes (22 address lines) so there is no need to worry about obsolescence.

FAST ACCESS AND CYCLE TIME — With an access time of 240 NSEC end cycle time of 400 NSEC one is insured the best throughput on the POP 11/23 system.

PARITY — The CI-1123 generates end checks parity for eech byte of memory. Totally DEC compatible.

BATTERY BACKUP POWER CONSUMPTION — Power requirement for the module is only 1.2 AMP from the 5 volt supply. The CI-1123 is easily configured for battery beck-up mode of operation requiring only 300MA from a single 5 V back-up supply for 256KB memory in the down state.

SINGLE QTY. PRICE: 32K x 18 SS7S. 128K x 18 *1925.

64K X 9 EXORCISER® I SINGLE BOARD MEMORY

For Exorciser I, Exerciser II and Rockwell System 65.

FAST ACCESS AND CYCLE TIME — Data access time Is 225 NSEC and cycle time Is 400 NSEC, allowing the unit to work as a static RAM at clock rates In excess of 1.5 megahertz. For 2 mega hertz operation the board can be easily configured to utilize a cycle stealing refresh operation.

ADDRESSING — On-boerd memory select is available in 4K increments

up to 64K words of memory on either the VUA or VXA control inputs.

PARITY — On board even perity with output jumper select to the system bus es e perity error or non-maskable interrupt.

Complete board power consumption is under 7 watts.

SINGLE QTY. PRICE: B4K x 9 $575.

Tasted and burned in. Full year warrenty.

DONTASK WHY WE CHARGE SO UTTLE, ASK WHY THEY CHARGE SO MUCH.

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MuMtai It ■ IndNMrit'Of At Mtl Ctip. LSI R tt t tnitiMrit tf H|itil Ev'^pMNM Cup. EXOacittr it t MriiiMik tff Motarals

Circle 69 on Inquiry card.

BYTE M»y 1981 279

Circle 218 on inquiry card

The

reachable

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STAR models are available that Interface directly with RS232 machines such as APPLE, ATARI, and NORTH STAR or IEEE 488 machiriiKS such as the PET, and that operate with either U.S. or European frequencies.

Using Interrupts

on the Apple II System

George M White Computer Science Department University of Ottawa Ottawa, Ontario KIN 6N5 Canada

Tlie designers of the Apple II personal computer made a judicious choice of software/hardware tradeoffs. The most important software

A surprising feature of the Apple II's system

software is that It mal<es little use of the

6502 interrupt system.

systems are stored in ROM (readonly memory) at high addresses where they are, for the most part, out of sight. Since the monitor, BASIC interpreter, and miniassembler are stored in ROM, they cannot be destroyed by user programs running

Acknowledgment

Most of this article was written while the author was enjoying the incomparable hospitalite of L'lnstitut de Recherche d'lnformatique et d'Automatique in Rocquencourt, France.

out of control, nor can they be altered to produce strange results.

A surprising feature of the Apple II's system software is that it makes little use of the interrupt system of the 6502 microprocessor. However, the creators of the monitor have correctly assumed that some users might want to make use of interrupts, so they have provided several facilities to aid the user in doing so. The hardware and software facihties permit the user to write interrupt-service routines and to wire up interrupt generators that easily fit into one or more of the eight I/O (input/output) card slots, conveniently located under the Apple's removable plastic cover.

Interrupt-Service Software

Let's compare interrupt-service routines to program subroutines. In the BASIC language, subroutines are called at a known location within a program by a GOSUB statement. The subroutine is not executed (or shouldn't be) until the GOSUB statement is encountered during the course

Available throughout the U.S., Canada, and Europe. For information and nearest dealer, call (408) 734-9810 or TWX 910-339-9519.

PRENTICE

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280 May 1981 © BYTE Publications Inc

len reasons why your floppy disk

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More than four decades of experi ence in magnetic media-BASF invented magnetic recording tape, the forerunner of today's wide range of magnetic media, back in 1934, and was the first independent manufacturer of IBM-compatible floppy disks.

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Gross-linked oxide coating-fpr low head wear and long troublefree media life.

Total capability - one of two mani^cturers in the world that ' takes both 8" and 5.25" models, g^j^ tape and disk experience, and manufactures floppy disk drives.

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Packaging to suit your requirements—standard flip-top box, Kassette 10® storage case, or bulk pack.

100% certification-every single disk is tested at thresholds 2-3 times higher than system requirements, to be 100% error-free.

For the name of your nearest supplier, write BASF Systems, Crosby Drive, Bedford, MA 01730, or call 617-271-4030.

BASF

Floppy Disks Mag Cards Cassettes Computer Tkpes Disk Packs Computer Peripherals

circle 44 on Inquiry card.

circle 195 on Inquiry card.

Spelling Checker for Professionals.

SPELLGUARD eliminates spelling and typographical errors In documents prepared with CP/M' or CDOS^ word processors.

SPELLGUARD is a unique program that leads the microcomputing Industry In Its efficiency, ease of use, and reliability.

FAST

• Proofreads 20 pages In under one minute.*

POWERFUL

• 20,000 word dictionary, expandable with single keystroice.

• Properly iiandles iiypiiens and apostrophes.

• Allows multiple, technical dictionaries.

RELIABLE

• Over 500 shipped by March 1981.

• 30-day money-bacic limited warranty.

• Industry leading Softguard feature ensures disicette copy of program is undamaged.

EASY TO USE

• On-line help feature.

• Misspelled words marlced In text for easy, in-context correction.

• Examples of ail functions in 120 page manual.

COST EFFECTIVE

• SPELLGUARO'S unique speed and accuracy easily recovers the suggested $295 price.

'Time estimates based on double density 8" diskettes and 4Mhz system.

D'ademarks: 'Digital Research, ^Cromemco

Contact your local dealer or write ISA for a SPELLGUAltD brochure.

The fast, accurate proofreader.

INNOVATIVE SOFTWARE APPLICATIONS

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of the program. Subroutines are usually written to perform a specific action such as altering values of variables, I/O operations, etc.

Interrupt routines, on the other hand, are called at a specific point in time. An interrupt signal arrives, and the interrupt-service routine is called. There is no warning. The signal can arrive at any time, and the program being executed can be interrupted at any point.

The interrupt routine is a program like any other program. It can do everything an ordinary program can do, such as calculate numbers, manipulate strings, ring bells, or print messages on the console. Usually, the interrupt system found on microprocessors is used to control a computer peripheral device or to monitor and control external machinery.

The interrupt system can continuously watch the temperature of a furnace, the condition of a fire or burglar alarm, or the time of day. When something unusual happens, when the temperature goes too high or a burglar alarm sounds, the interrupt system alerts the computer to respond to the unusual condition and perform necessary actions.

However, the writing of such a program is a demanding task. The programmer must be aware of five aspects of interrupts that involve both the hardware and software of the system.

Necessary Conditions

1. There must be an external device capable of sending an interrupt signal to the computer.

The smaller systems used by novice BASIC programmers usually do not contain devices capable of generating interrupts. Even if they did, the BASIC language system available is not able to handle them directly, because most versions of BASIC do not recognize that interrupts exist.

The external device that sends the interrupt can be anything external to the processor and memory; it does not have to be physically located outside the computer box itself. Some common devices used as sources of interrupts are real-time clocks, terminals, and other computers. This list

is not exhaustive. Anything capable of generating an electrical signal— automobile, household appliance, or burglar alarm—can be' used as a source of interrupts.

2. The processor must be capable of receiving and acting upon the interrupt signal.

This implies not only that the signal must be wired into the computer with all its voltages having the correct values, but also that the processor must be set up to respond to the signal. We shall see later that the 6502 microprocessor can actually ignore some kinds of interrupts if the programmer has told it to ignore them.

Anything capable of generating an eiectricai

signal—automobile, iiouseiiold appliance, or burglar alarm—can be used as a source of interrupts.

3. The processor must be able to tell which of several possible devices generated the interrupt.

If there is only one interruptgenerating device wired into the system, there won't be any problem identifying the source of the interrupt when it arrives. But if there are several interrupt sources—all trying to get the attention of the processor—the computer must have some way of telling which interrupt source is responsible for sending the signal, so it can take appropriate action.

4. The processor must respond to the interrupt by doing something.

When an interrupt signal arrives and is accepted by the computer, the program must perform an appropriate action (ie: "service" the interrupt). In some cases, this action is very simple, such as printing a character on a terminal. In other cases, the system may have to do something much more complicated, like placing a telephone call, sounding an alarm, or aborting the program it was executing.

282 May 1981 ® BYTE PubUcaUoiu Inc

Energy Management

Security Systems

Control and monitoring of home and office made easy.

Now any computer with on RS-232 port, or any APPLE II, can communicate directly with the real world using our ever expanding line of carrier communications interfaces. Using the AC powerline for data eliminates running long wires to remote locations.

The SRIO (Serial Remote I/O interface) Operates up to 256 BSR System X-10 compatible control modules. Contains a real time clock and calendar with battery backup. Carrier receiver allows monitoring of remote input modules and receiving messages from the BSR command console or from other computers.

The ARIO (Apple Remote I/O interface)

Provides Apple II users the additional benefit of background operation. On board software includes 0 scheduler program.

TRADEMARKS—APPLE II: Apple Computer, Inc., System X-10: BSR Ltd.

The Remote Input Modules which connect to temperature, security and other sensors will be announced soon. Also additional types of remote I/O modules ore in development.

ORDER NOW I Orders received in May get a certificate for $10.00 off the price of your first remote input module.

PRICES: SRIO $250 Quantity discounts available. SRIO less clock $200 Add $5 per order for ship/hand.

ARIO $185 MN residents add 4% sales tax.

Circle the reader service number for our new catalog.

Intelligent Control Systems, inc.

P.O. Box 14571

AAinneapolis, MN 55414

(612)699-4342

We are in control.

Circle 198 on Inquiry card.

ByTEM«yl981 283

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i

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6502

MICROPROCESSOR

NMI 6

+ 5V

PIN 29 FROM EACH APPLE PERIPHERAL SLOT

>3.3K

SLOTO

SLOTl

SLOT 2

SLOT 7

Figure 1: The 6502 NMI signal and the Apple II peripheral slots. The NMI signal is

connected to pin 29 of each of the slots and is held high by the pull-up resistor shown. An interrupt is generated if the peripheral card in any of the slots presents a low impedance to ground to its pin 29.

5. After the service has been performed, the processor usually must return to the interrupted program and continue from the point of interruption.

When an Interrupt signal arrives and Is accepted by the computer, the program

must perform an appropriate action.

Usually (but not always), the interrupt has interfered with the execution of a program. After the interrupt has been successfully serviced, control should return to the interrupted program or process at the point of interruption without modifying the process in any way. Sometimes this program is nothing other than an endle^ loop waiting for interrupts to arrive.

Nonmaskable Interrapts

The Apple II has two separate interrupt lines entering its 6502 processor. They work somewhat differently.

Pin number 6 on the 6502 package is an active-low signal input called the nonmaskable interrupt, NMI. It is connected through the printed-circuit board to a pull-up resistor and to pin 29 in each of the eight I/O slots shown in figure 1.

If none of the circuit cards in the slots has anything attached to its pin 29, the potential at the NMI input observed by the 6502 is always held high by the pull-up resistor. This is the normal mode of operation. If a low impedance to ground is presented to pin 29 by any of the slots, the NMI line goes low, causing an interrupt condition to be generated in the 6502. This is the definition of the nonmaskable interrupt. This interrupt can be better understood by examining each of the five aspects presented earlier.

1. Any external device can generate an interrupt by presenting a ground (or low impedance to ground) potential to pin 29 in any of the I/O slots. Thus, the Apple II can have eight different interrupt sources, and they all may decide to interrupt at once.

2. The NMI signal is always recognized by the 6502 microprocessor, because it is nonmaskable. (Maskable interrupts will be discussed shortly.)

3. If there is only one device capable of sending the NMI signal, there is no question which device sent it. But if there are two or more interrupting devices, a problem arises. The 6502 microprocessor has only a single NMI input line, and every NMI signal goes there. In the Apple II, the processor can differentiate among several possible sources by polling the devices.

Polling is done by asking each device if it sent the interrupt signal or not. A program directs the computer

284 May 1981 © BYTS PubUcaUons Inc

A^H Licenced by Sincleir Research Ltd. ^_

Microcomputer

for everyone at a Micro Price

The IMicroflcQj - a new generation of

miniature computers

A COMPLETE COMPUTER for $149.00 for IK Kit

Post and Packing FREE

The unique and valuable components of the MicroAce

The MicroAce is not just another personal computer. Quite apart from its exceptionally low price, the MicroAce has two uniquely advanced components: the powerful BASIC interpreter, and the simple teach yourself BASIC manual.

The unique versatile BASIC interpreter offers remarkable programming advantages:

• Unique 'one-touch' key word entry: the MicroAce aliminatas a great deal of tirasome typing. Key words (RUN, PRINT, LIST, ate.) have their own singla-key entry.

• Unique syntax check. Only lines with correct syntax are accepted into programs. A cursor identifies errors immediately. This prevents entry of long and complicated programs with faults only discovered when you try to run them.

• Excellent string-handling capability takes up to 26 string variables of any length. All strings can unflcrgo all relational tests (e.g. comparison). The MicroAce also has string input to request a line of text when necessary. Strings do not need to be dimensioned.

• Up to 26 single dimension arrays.

• FOR/NEXT loops nested up 26.

• Variable names of any length.

• BASIC language also handles full Boolean arithmetic, conditional expressions, etc.

• Exceptionally powerful edit facilities, allows modification of existing program lines.

• Randomise function, useful for games and secret codes, as well as more serious applications

• Timer under program control.

• PEEK and POKE enable entry of machine code instructions, USR causes jump to a user's machine language sub-routine.

• High-resolution graphics with 22 standard graphic symbols.

• All characters printable in reverse under program control.

• Lines of unlimited length.

'Excellent value' indeedl

For just $149.00 (including handling charge) you get everything you need to build a personal computer at home... PCB, with IC sockets for all ICs: case: leads for direct connection to a cassette recorder and television (black and white or color!; everything!

Yet the MicroAce really is a complete, powerful, full-facility computer, matching or surpassing other personal computers at several times the price.

The MicroAce is programmed in BASIC, and you can use it to do quite literally anything, from playing chess to managing a business.

The MicroAce is pleasantly straightforward to assemble, using a fine-tipped soldering iron. It immediately proves what a good job you've done: connect it to your TV ... link it to the mains adaptor ... and you're ready to go.

Fewer chips, compact design, volume production-more power per Dollar!

The MicroAce owes its remarkable low price to its remarkable design: the whole system is packed on to fewer, newer, more powerful and advanced LSI chips. A single SUPER ROM, for Instance, contains the BASIC interpreter, the character set, operating system, and monitor. And the MirmAce IK hyln

(Add 6% Tax for Shipments inside California)

RAM (expandable to 2K on board) Is roughly equivalent to 4K bytes in a conventional computer typically storing 100 lines of BASIC. (Key words

occupy only a single byte.)

The display shows 32 characters by 24 lines.

And Benchmark tests show that the MicroAce is faster than all other personal computers.

No other personal computer offers this unique combination of high capability and low price.

The MicroAce teach-yourself BASIC manual.

If the features of the BASIC interpreter mean little to yoU'don't worry. They're all explained in the specially-written book free with every kit! The book

makes learning easy, exciting and enjoyable, and represents a complete course in BASIC programming from first principles to complex programs. (Available separately purchase price refunded if you buy a MicroAce later.) A hardware manual Is also included with every kit.

The MicroAce Kit:

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$169.00 with 2K

Demand for the MicroAce is very high: use the coupon to order today for the earliest possible delivery. All orders will be despiilched in strict rotation. If you are unsuccessful in constructing your kit, we will repair it for a fee of $20.00, post and packing FREE. Of course, you may return your MicroAce as received within 14 days for a full refund. We want you to be satisfied beyond all doulit c'inri wo liave nn doubt Iliai you will be.

Z60 A microprocessor chip, widely recognised as the best ever made.

id SB HI 8S 9P (K Wl ■ ■[■■■Hltt»iiili

Your MIcroAca kit contains...

• Printed circuit board, with IC sockets for all ICs.

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• New rugged keyboard, touch-sensitive, wipe-clean.

• Ready-moulded case.

• Leads and plugs for connection to domestic TV and cassette recorder. (Programs can be SAVEd and LOADed on to a portable cassette recorder.)

• Mains adaptor of 600 mA at 9VDC nominal unregulated.

• FREE course in BASIC programming and user manual.

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I Send Check, Money Order or quote your Credit Card No. to: * MicroAce 1348 East Edinger, Santa Ana, California, Zip Code 92705. or phone (714) 547 2526 quoting your Credit Card Number.

Quantity

Description

TOTAL

MicroAce Kit 1K

$149.00

MicroAce Kit 2K

$169.00

Manual

$10.00

1K Upgrade Kit

$29.00

Shipments inside California ■ add 6% TAX TOTAL

Amex. Diners Check

Money Order Master Charge Visa

Card No..

Exp. Date

Circle 252 on inquiry card.

BYTE May 1981 285

Circle 21 on Inquiry card.

CALCULATOR MODULE SELECTOR

for

Texas Instruments

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• Holds four Solid State Software™ libraries and eliminates the need to turn off the calculator and physically change modules.

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to examine the status of each device which might have sent the interrupt. The details of this depend greatly on the way the devices are wired up, but in principle some of the 50 lines in the I/O slots can be used by the device to present logical flags or form data buffers. Examination of these signal lines by the program can then determine whether the device in question sent the NMI or not.

Daisy-chain inhibition of interrupts can be provided for in hardware by using control lines INT IN (pin 28) and INT OUT (pin 23) on the I/O slots, which are reserved for such a purpose. Various I/O devices can thereby have different priorities for interrupt servicing.

The Apple II's motherboard contains the wiring that links the boards together. This arrangement is shown in figure 2. Pin 28 (the INT IN line) of slot 0 has no connection, but pin 23 (INT OUT) of slot 0 connects to pin 28 of slot 1. Pin 23 of slot 1 connects to pin 28 of slot 2, and so on, up to slot 7. Pin 23 of slot 7 has no cormection.

There are several methods for wiring the daisy chain, but in the most common configuration there is a low impedance (or a direct connection) on each interrupt-using card between INT IN and INT OUT. I/O cards have priority in interrupt service according to their physical position in the I/O slots. Cards in the lowernumbered slots have higher priority,

while cards in the higher-numbered slots have lower priority: it is not that the processor will process the I/O functions of the higher-priority cards before dealing with lower-priority cards if interrupts occur at the same time, but that the lower-priority cards are not permitted to generate an interrupt signal until the higherpriority device allows it.

In this scheme, I/O slots must be contiguously filled with cards so a continuous circuit, the daisy chain, is completed between the cards on the INT IN and INT OUT lines. I/O cards that do not use the interrupt system can be placed between cards that do if the noninterrupting cards have a jumper or connection between the contacts for pins 28 and 23 to maintain circuit continuity.

The highest-priority I/O card must reside in a lower-numbered slot than any other interrupt-generating card. The highest-priority card is special: it is responsible for placing a voltage indicating a high logic condition (usually -H 5 V) on the INT OUT pin for its slot. The lower-priority cards need not have this capability. They need only have the capability of opening the circuit between the INT IN and INT OUT pins for their slots.

Suppose, for example, that there are interrupt-generating I/O interface cards in slots 5, 6, and 7. The card in slot 5 must be capable of placing a potential of -1-5 V on the INT OUT cormection. The card in slot 6 must

APPLE PERIPHERAL SLOTS

INT OUT

INT IN

SLOT?

INT IN

Figure 2: Using daisy chaining to create a priority system of interrupts. The INT OUT (pin 23 of each slot) and INT IN (pin 28 of each slot) signals are connected to each other to create a daisy chain that is broken by an interrupting slot, A peripheral device is not allowed to generate an interrupt unless it has highest priority or "permission" from higher-priority devices. Peripherals in lower slots have a higher interrupt priority than peripherals in higher slots. See the text for details.

286 May 1981 © BYTE PublicaUoiu Inc

The Text Solution for APPLE II®

Now APPLE II® Owners Can Solve Text Problems With VIDEOTERM 80 Column by 24 Line Video Display Utilizing 7X9 Dot Character Matrix

Perhaps the most annoying shortcoming of the Apple IT- is its limitation of displaying only 40 columns by 24 lines of text, all in uppercase. At last, Apple II® owners have a reliable, trouble-free answer to their text display problem. VIDEOTERM generates a full 80 columns by 24 lines of text, in upper and lower case. Twice the number of characters as the standard Apple II® display. And by utilizing a 7 by 9 character matrix, lower case letters have true descenders. But this is only the start.

VIDEOTERM, MANUAL, SWITCHPLATE

VIDEOTERM

7X12 MATRIX 18X80 OPTIONAL

! Ml U '()»♦.-. / 112 3 4 5 6 7 8 9 ! i < = >? ( A B C D E r 6 H 1 J K L n N 0 P JIIS T U V U X Y Z [ \ ] t . ' 1 b c d e r 9 h i j k lino pqrstiivwKy2{l)"t

BASICS

Pascal

Other Boards

Advanced Hardware Design

Available Options

Firmware

VIDEOTERM lists BASIC programs, both Integer and Applesoft, using ttie entire 80 columns. Without splitting keywords. Full editing capabilities are offered using the Escape key sequences for cursor movement. With provision for stop/start text scrolling utilizing the standard Control-Sentry. And simultaneous on-screen display of text being printed.

Installation of VIDEOTERM In slot 3 provides Pascal immediate control of the display since Pascal recognizes the board as a standard video display terminal and treats it as such. No changes are needed to Pascal's MISC.INFO or GOTOXY files, although customization directions are provided. Ail cursor control characters are Identical to standard Pascal defaults.

The new Microsoft Soltcard" is supported. So is the popular D. C. Hayes Micromodem II* , utilizing customized PROM firmware available from VIDEX. The powerful EasyWriter' Professional Word Processing System and other word processors are now compatible with VIDEOTERM. Or use the Mountain Hardware ROMWriter* (or other PROM programmer) to generate your own custom character sets. Naturally, VIDEOTERM conforms to all Apple OEM guidelines, assurance that you will have no conflicts with current or future Apple 11"^ expansion boards.

VlDEOTERM's on.board asynchronous crystal clock ensures flicker-free character display. Only the size of the Pascal Language card, VIDEOTERM utilizes CMOS and low power consumption ICS, ensuring cool, reliable operation. All ICs are fully socketed for easy maintenance. Add to that 2K of on-board RAM, 50 or 60 Hz operation, and provision of power and input connectors for a light pen. Problems are designed out. not in.

The entire display may be altered to inverse video, displaying black characters on a white field. PROMs containing alternate character sets and graphic symbols are available from Videx. A switchplate option allows you to use the same video monitor for either the VIDEOTERM or the standard Apple If display, instantly changing displays by flipping a single toggle switch. The switchplate assembly Inserts Into one of the rear cut-outs in the Apple II" case so that the toggle switch is readily accessible. And the Videx KEYBOARD ENHANCER can be installed, allowing upper and lower case character entry directly from your Apple II' keyboard.

1K of on-board ROM firmware controls all operation of the VIDEOTERM. No machine language patches are needed for normal VIDEOTERM use.

Firmware Version 2.0

7x9mairix Display 24 X 80 (fiill descenders)

Characters Options

7x12 matrix option: Alternate user definable character set option: Inverse video option.

1Sx 80 (7 X12 hnatrix with full descenders)

Want to know more? Contact your local Apple dealer today for a demonstration. VIDEOTERM is available througfi your local dealer or direct from Videx in Corvallis. Oregon, Or send for the VIDEOTERM Owners Reference Manual and deduct the amount if you decide to purchase. Upgrade your Apple II' to full terminal capabilities for half the cost of a terminal. VIDEOTERM. At last.

7X9 MATRIX 24X80 STANDARD

Apple II* is a trademark of Apple Computer Inc. ROMWriler* is a trademark of Mountain Hardware Inc. Micromodem ir Is a trademark of D. C. Hayes Associates inc. Sodcard* is a trademark of Microsoft

EasyWriter' 15 a trademark of Information Unlimited Software Inc.

PRICE: • VIDEOTERM includes manual S345

• SWITCHPLATE S 19

• MANUAL refund with purchase... .$ 19

• 7X12CHARACTERSET S 39

• MICROMODEM FIRMWARE S 25

APPLE II® OWNERS!

introducing the

KEYBOARD & DISPLAY

ENHANCER

'PUT THE SHIFT AND SHIFT LOCK BACK WHERE IT BELONGS • SEE REAL UPPER AND lower CASE ON THE SCREEN ■ ACCESS ALL YOUR KEYBOARD ASCIt CHARACTERS

Videx has the perfect companion for your word processor software: the KEYBOARD AND DISPLAY ENHANCER Install the enhancer in your APPLE 11 and be typing in lower case just like a typewriter. If you want an upper case character, use the SHIFT key or the CTRL key for shift lock. Not only that, but you see upper and lower case on the screen as you type. Perfectly compatible with Apple Writer and other word processors like, for example. Super-Text.

If you want to program in BASIC, just put it back into the alpha lock mode; and you have the original keyboard back wfth a few im

provements. Now you can enter those elusive 9 characters directly from the keyboard, or require the Control key to be pressed vAth the RESET to prevent accidental resets.

KEYBOARD AND DISPLAY ENHANCER is recommended for use with all revisions of ihe APPLE II It includes 6 ICs. and EPROM and dip-switches mounted on a PC board, and a jumper cable. Easy installation, meaning no soldering or cutting traces. Alternate default modes are dip-switch selectable. You can even remap the keyboard, selecting an alternate character set, for custom appltcations.

PRICE • KDE-700 (REV. 7 or greater) $129.

• KDE-000 (REV. 6 or less) $129.

Apple IF is a trademark of Apple Computer, Inc.

VIDEX I 897 N.W. Grant Avenue Corvallis. Oregon 97330 Phone (503) 758-0521

Circle 429 on Inquiry card.

BYTE May 1981 287

circle 83 on Inquiry card.

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have a low impedance from INT IN to INT OUT as a normal condition (so the card in slot 7 will be able to "see" the +5 V provided by the card in slot 5), and the carets in both 6 and 7 must be able to detect the absence of the +5 V potential on the INT IN line. The controlling circuitry of the slot-6 and slot-7 cards must recognize the absence of the INT IN high logic level and interpret it as denoting a condition in which the lower-priority cards are not pennitted to generate an interrupt.

When the slot-5 device needs to interrupt the processor, it causes a low logic level to be placed on the NMI line, pin 29, as previously described. At the same time, it removes the high logic level from the INT OUT line, pin 23. The slot-6 and slot-7 devices sense the low level on their INT IN pins, and they refrain from issuing an interrupt signal as long as this condition persists.

Meanwhile, the polling software in the processor polls the slot-5 card, as it has been set up to do first; the software polls the I/O cards in order of priority. Finding the slot-5 card needing attention, the software branches to the appropriate interrupt-servicing routine.

When the interrupt routine for the slot-5 device has finished its business, the interrupt condition is cleared, and control returns to the interrupted processing. At this point, the slot-5 card restores the -f 5 V potential to the INT OUT line, and the slot-6 and slot-7 cards can issue interrupts as necessary.

If the slot-6 card needs to issue an interrupt (and -1-5 V is present on its INT IN pin), it activates the NMI line in the same way. But because it is not the source of the -f 5 V on the INT IN/INT OUT path, it merely activates logic to create a high impedance between the INT IN and INT OUT pins for its own slot, thereby preventing the slot-7 device from seeing the +5V INT IN level. In this way, the slot-6 card asserts its higher interrupt priority over the slot-7 card. When the slot-6 interrupt has been serviced by the processor, the low impedance is restored between the INT IN and INT OUT pins of slot 6, and

the 4-5 V potential propagates once more along the motherboard traces to slot 7.

4. When an interrupt arrives at the 6502, the microprocessor responds by performing the following operations on its stack:

Push program-counter high byte Push program-counter low byte Push status register Jump via hexadecimal FFFA

Thus, the PC (program counter) and the status register are pushed (saved) onto the stack (the high byte of the PC is pushed first, then the lower byte, and, finally, the status register, P). After these stacking operations, the processor executes an indirect jump via hexadecimal memory location FFFA (ie: the location jumped to is the contents of FFFB (high byte) and FFFA (low byte) considered as a 16-bit number). In the Apple II computer, this is a ROM address, and Apple Computer Inc has set its contents to hexadecimal 03FB (remember that the lower byte contains the low-order address). Therefore, the system jumps to hexadecimal location 03FB and starts executing what it finds there. This area contains programmable memory, and it is the user's responsibility to start the interruptservice routine there. Unfortunately, this area is organized so there are only 3 bytes of memory actually available here. Because of this, the user must store a jump instruction in these 3 bytes that will direct execution to another area of memory, typically to the page beginning at hexadecimal location 0300 or to some higher area such as hexadecimal 0800 or 1000.

Generally, the first instructions in the interrupt-service routine are those to save the present value of the A, X, and Y registers on the stack. After that, the interrupt service is performed, and the A, X, and Y registers are restored. The routine should always be terminated with an RTI (return from interrupt) instruction. This instruction will unstack the status registers and program counter, and execution will continue from the point it had reached just before the occurrence of the interrupt. The inter

288 May 1981 © BYTE PubllcaUoiu Inc

DYNA

{^uaiiiy soj

COMP

Tiwarejor .

ATARI

TRS-80 (Level II)*

PET

PIvin111

APPLE n Plus

GP/M 8" Disk

GAMES, SIMULATIONS, EDUCATION and MISCELLANEOUS

BRIDGE 2.0 (Avilllble for all computers) price: S17.9SCuMiie/S2l.95 DlskeKe

An ilNnduiiveverHiMof llib iimpO|NdirorG)ud|^^ BIDSandPLAVSfiihcrcomnGt or duplicaic bridge.

Dcpcndini on ibc comnM. yonr coMpuur opputentt wB ebher idv Uieoncnie OR rfeftme. If you bM im tiigh. thecnopuier double your coniraeil BRIDGE I.Oprevida diiUmBingenienainmeni for wlvuceil playm and ti an ncdlenr leamini tool far itie

HKAKTS 1.5 (AvHiiahk for all computers)

■ Dbkclle

CHIBBACEfTRS M0(.

IliiMs .imply ll.c l>LM,r,l.

w game, Ths giaphic

Price: S14.95 Cuwite/5I8.9S Ulskelk

il program Tor Ihc cribbagc player in »arcli ora wonhy □pixincni a& »ell are iuperb and aisembly linguaie touimei provide rapid cuccuiiun.

STUD POKER (ATARI only) Pike: S1I.9S CumI1c/S15.93 Dlikclle

This w ih; clasticlamblRHcairifUWi TlieeMnpuinM whal you uc. The

tompuift don noicheal and luiMfb'bell Ihc oddi. However, li MMncilmei Muffil Aho included li a five cud draw poker belling pracuce piogtwn. Thii package wUI run on ■ IHC ATARI. Color, ■raphla, found.

POKER PARTV (AvailiUc for all compotcn) Price: S17.95 CmltumXM Olikeiie

POKER PARTY iiadraw poker limulaiion based on iht book. POKER, by Otwald iacoby. Thii Hihcmoti comprriieniive vertion ataiUblf for mictocompuiers. The party coniim of youtuK and tu other (compuier) playeri. Each of ihne playert (you will get io knim thcmj hai a diffetcni perionilily in the Torrr of a ^aFvinfi ptofKniiiy lo bluff or fold under preiiure. Pnciice «iih POKER I'AK IV t^clorc going id ih«t expeniive game lonighi! Applr Cassciie and diikellc vcnioni lequire > 31 K lor larger) Apple It.

NOMINOES JIGSAW (Atari. Apple anil TRS-80 only) Price: $16.95 CuNlle/no.95 Olikeitr

A iiguir puixle on >aur conpuicr! Conqriece the puzzle by lelectinf your piem from a lable coniiHinf of 60 dlfftttni ihapes NOMINC^ JIGSAW it a vinuoM) ptogranunlas effort. The gtaphki are lupertativc and ihc punk wHl dulhntg you with lu ihrce leveli of tifficuliy. Scotini It bated upon the number of tuetiet taken and by ih« difficulty of ihe board tci-ap.

CRANSTON MANOR ADVENTURE (NoHb Slar only) Price: S19.95

At lail! A comprehenilve Adventure game for the Nprlh Star. CRANSTON MANOR ADVENTURE likes you in tnyiterious CHANSTON MANOR where you atlempt lo gather faboloiit.trcanuts. Lurking in the manor are wild animaliand robots who viti not line up the ireaiurei wilhoul a fighi. The number of lOOnH lilKaUrand the atsociated deictlptioni are much more elabcraie than the Lurrcnl popular tents ol Adventure progrims, nuUnllld* game Ihe.IOp in lU Cllst. Pla> can be stopped at any time and Ihe tiatui stored on diskette. Requites 32K.

VALOEZ (Available for all computers) Price: S14.9S Cauclie/$18.9S Dlikcite

A limulaiion oriuperlanker navtgaiion In the Ptlnce Williira Sounil «nd Vatdeg Nirrowi. The program met an extensive 2S6XZ36 element radar map and employi phyilol modeii of ship reiponse ami lUal paiiernt. Chart your own nunc ihrouih ship and iceberg ir a lflc. Any standard terminal may be used for ditirfty.

FLIGHT SIMULATOR (Available for all computers) PriniS17.9$CagMllc/S21.95lHtkelle

A lealiMicand ciiei^sivc maihematicaJ simulation of lake-nff. Hlght and landing. ThepragtafflUllltmaerodyaanifecquationiand Ihc diaraiieniiict ol i real air toil. You can practice insirumenl apprtischei and nivlgatloh Utingradlallllld eMtljU|he8(BD|i. Them

udsanicit flyer tan iUa perform loops, halt-rolls and similar aerobaiic maneuvers.

STARTREK 3.2 (Available for all computers) PricciS 9.95CMH«e/SU.95DMiclU

[his IS ilic daiMc StiTKek limulaiion. but wiih several new features. For example, the Klingons npw diOOl al the Eaie^Hile wilhoul warning sirhile also aiitcking siarbases in other quadrants. The Klingons also aiiack with both light and hetvy cmiien and move when thai all Tit siiuaiton w hectic when ihe Enterprise is besieged by three heavy cruimt and a tiarbaieS.O,S. ii received! The KHngons get evcnl

CHESS MASTER (North Star and TRS^O only) Price: $19.95 Cuaclle/S23.95 Dbhetie

TMt com^e and very powerful program provides five levels of play, li Includet caitling, en patiaol cape urn and the peomoiion of pawns. Additionally, the board may be prod before Ihe start of play, per mining the cumi nation of "book" playt.Tomaiimiitetecu lion ipccd. Ihc program ii written in assembly bnguagc lb) SOFTWARE SPECIALISTS of California). Full graphics are employed m the TRS4D version, and two widths of alphanumeric display are provided lo accommodate North Star uiers,

BLACK HOLE (Apple only) Price: $14.95 Casselle/$iS.95 Dbkeiie

This it an ndllng graphical simulation of the problems involved in closely observing a black hole with a space probe. The object is lo enter and maintain, for a prescribed lime, an orbit dose lo a small black hole. This it to be achieved wiihoul coming so neai iheanomalt thai the tidal stress destroys the probe. Control of the crafi is realisiicilly simulited using tide Jets for roiition and main thrusteis for tccclettlion. This program employs Hi-Res graphics and it eduealional as well as challenging,

HODGE PODGE (Apple only. 48K Integer BASIC) Price: $19.95 Cag«ilte/$23.95 DUkelle

Let HOtXlE PODGE be your child's baby sitier. Pressing any key on your Apple will result in a different and Intriguing "happening" (elated to the ietur or numbirof the choicn key. The ptogram't graphlo. color and lound at* a dclifht for diUdren from agct Vaxo"). HODGE PODGE ii-s noH'fntlmldtitini teaching derfcc which btlnci a new dim.nulon to ihe use ofcomputen In eduo^on. HODCE POOGi nqufres a 4XH AppM running with Integer BASIC

TEACHER'S PET I (AviUabk for iU compnten) Pricat s 9.95 Caiaeite/Sl3.9S Obkcite

This it the nm of OYNAC(Hif P's educational pukiigcs. Mmarily buendtd for preschool lo role 3. TEACHER'S PET provides the young iludeni with coumlng practice, Iciter'-wont recognbidn and three Itvib of math iklU excrdies.

SPACE TILT (Apple only) Price: SIO.95 CbimUc/SM.95 Dlikciic

Uieihegaaicpaddnlo till the plane of the TV icteen to "roll" abalilMo a hole tnibeierccn. Sound ilnplc?r'M when the hole gets smaller and smaller! A iHitU-bi timer ailows you to meauire your skill against oihcn M this hat^l^fonnliig anion liuhc.

MOVING MAZE (Apple only)

MOVING MAZEemptoytlbegaffles paddles 10 direct a PLck (ron land randomly) buih and b continually being modified. Tie objo Scoring IS by an eiapscd lime indicator, and ihtec levels ol play a

Price: $10.95 CMMtte/S]4.95I}likclie

I maze to Ihe other. However, the reaae it dynamically .s the mate wfthOut iouchhig(or beingMt by|a wall

ALPHA FIGHTER (Atari only) Price: $14.95 Cauclie/$ia.95 DUkeiit

Two eicellent graphics and action programs in onel ALPHA FIGHTER requires you lo destroy the alien starshipt passing through your sector of the galuy. ALPHA BASE is in Ibe path of an dien UFO invasion; lei five UFO't gel by and the game ends. Both games require the joystick and gel progressively mote difnculi the higher you score!

INTRUDER ALERT (Atari only) Price: $16.95 CBiaclte/S».95 Dlikeiie

This Isa fait paced graph let game which places you in the middle of the "Drcadilar" having Just stolen lis plans. Thedroids have been alerted and are directed to destroy you at all costs. You must find and enter your thip to escape with the plans. Rve levels of dirriculis are provided. INTRUDER ALERT requires a joysiii:k and will run on I fiK syMcms

GIANT SLALOM (Atari only) Price: S14,95 CaMcnc/$lfl.95 [>bkeiie

This real-lime action game is guaranteed addlctlvel Use the joystick to control your path through slalom courses consisting of both open and ilined gales. Choose Irom different tcvels.of dlfHintlty, race against Oilier players or simply lake praLlice runs againsi ihc (.lock CrlAN r SI AI.OM svill run on I6K systems.

CRYSTALS (ATARI only) Price; $ 9.95 C«iaeite/$IJ.9S Diskette

A unique algorithm randomly producet fatdnaUng puhfcs dtqilnys accompanied with tones which vary as the paiterni are built. No two paiiems ate the same, and ihc comtrined riYea of ihe ioiind andgraphlct aremetmeriiing. CRYSTALS hat been used in local siotes to demonsiraie ihe sound and color features of the Atari.

CHOMP-OTHELLO (Atari only) Priet:S11.950MMttt/$l5.95Dliketit

CHOMP-aTHELI cr Ir s really isso challenging games in one. CHOMP it similar In concept 10 NlMi lOU must bile off part of a cookie, but avoid taking ihc poisoned portion OTHELLO is Ihc popular bmtdiametci 10 filUyuiiliieihe Atari's gfaplricscapabilii) li IS also ter> hard lo beat' This package will run an a I6K system.

GAMES PACK I (Avilliblc for all coraputen) Price: $9.95 Ca>acile/SI3.93 DItketit

GAMLS PACK I EOMains ihe classic computer games of BLACKJACK, LUNAR LANDER, CRAPS. HORSERACE. SWITCH and more. These games have been combined tnio one htrgc program for ease In loading. They are individually accessed by a convcmeni

GAMES PACK II (Available for all compulcn) Price: $9.95CkiM«e/SI3.95DlBkene

GAMES PACK tl indudet the games CRAZY EIGHTS. iOTTO, ACEY-DUCEY, LIFE. WUMPU5 and otbns. As vnih CA.MES

PACK I, all the games are loaded at one program and are called from a menu.

Why pay ST.V] or more pet program when you can buy a DYNACOMP collection for lutl 19.03?

NORTH STAR SOFTWARE EXCHANGE (NSSE) LIBRARY Price S9.95 Dbkctie

UYNACOMP now distributes tlw 10 * volume NSSE library. Most of these diskcitci offer an oulslinding value for the purchase price. Write (01 details icgaidlng the imnienis of this library and quaniliy Ifour or more) purchases.

Availability

DVNACOMP software is supplied with complete documental ion containing dear enplanaiio programs will run wiihm 16K program memor> spate (ATARI tequirc^ ;4K) I xtepr sshere r TRS-niLcvd llland Apple lApplcsofll cassette and disVciic «d! .v

tionally, most programs can be obtained on sianilaid 11 KM lonii.i: i i [' vi i' .iip.'. . i- k

I and examples. Unless oihrrsiisi

BUSINESS and UTILITIES

MAIL LIST 2.2 (Apple, Atari Rnd North Star diskette only) Price: SJ4.95

This program is unmatched in its ability tosiorc a maximum number of addresses on onediikeiie (minimum of I tWpct diskette, more than 2200 for "double dendty" tystemt 1). lu many feaiUKi indode a^ihabeliB and lip code sorting, tebd printing, merging of Hies and a un(()ue keyword seeking roittine which retrievct entries by a virtually limlllesi selection of oter defined codes. A very valuable program!

FORM LETTER SYSTEM (FLS) (Apple and North Slir diskette only) price: S21.95

Use FLS 10 create and edit form lettert and addrest llsii. Form letUn are produced by automatically inter)Ing eac^ address into a predetermined portion of your letter. FLS It ooraidctely cdmpatlbte wllh MAIL LIST l.I. which may be used to maitage your address

files.

IT S and MAIL LIST 2.2 are available asacombined package for M9.95.

PERSONAL FINANCE SYSTEM (ATARI only) Price: $34.95 DIskeiie

prSis a single disk menu oriented system composed Of lOprogramt designed lo organize and simplify your personal finances f eaiiires include a jOO iransaciion capacity: fast aCCeU: 26 Option^.USCr codcti data retrieval by nonlh. nidear payee: optional printing

reports, checkbook baiani'ing; bar graph plotting and more, Abe pTotMei on ihc diskette b ATARI DOS 2.

FINDIT (North Star only)

tins IS a ihiee-iri-one program which maintains in I'ul (eg: plumbers) and Reference (eg: magazine a nivcrsaiy and appointment searches for the perso jrc :icccsstd by a single keysvoid or by cross-tefe

DFILE (North Slir only)

Price: SI 9.95

ywords of three types: Personal (eg: last name), Commer. ) In additionio keywordsdirchcs, Iherearebirthday.aonl searches for the commerda) records. Reference records

Price: Sl»l.«

sarinMy jccuinulaies. UFILF: is easy lo set up and use. It will organiic your disks lo provide cftleieni locating of ihc desired lilc ur pro

GRAFIX (TRS-80 only) Price: S12.95 Casselte/S 16.95 Disketlr

This unique program allows you to easily aeate graphics directly from the keyboard. You "draw" your Tiguie using the program's eiteniive cursor controls. Once the flgureis nude, it is aulomatlcatiy appended to your BASIC program as a string variable. Draw a "happy face", call it HI and then print it from yojr program using PRINT HJ! This is a very easy way to create and save graphics.

TIDY aRS-80 only) Price: $10.95 augelte/SI4.95 Diikelle

TIDY it an auembly lutuage prograin wldGfa alltnvs you to renunlber the lines in your BASIC programs. TIDY also removes itn. necessary ijiacet and RBMvk statements. Tiie rendl b a mnq^

signilfeantly fatter. Once loaded. TIDY rcmalnt In memory: you may load any number of BASIC programs wlthckii having to tdoad TIDY!

STATISTICS and ENGINEERING

DATA SMOOTHER (Nol available for ATARI)

Thb special data smoothing program may b; used to rapidly d arc equally spaced. The software features choice in decree and

Price: S14.95 CHaelU/SM.95 UikcUe

km from noiqr business and cn^oceringdata wHKh IS smoothed lint and second derivative calculation.

FOURIER ANALYZER (Available for all coraputen) Price: $14.95 CmetttmhM Dfadicltc

Use this program to examine the frequencyspeclraof limited duration lignali. The program fcaiurei automatic scaling and plaiting of the input daia and retuitt. Practical appliatioiu include the analysis of complicBted patterns in such fields as elenronks, communications and business.

TFA (Trangfer Function Analyzer) Price: Sl9.95CasHitc/S23.95Dbketie

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BYTE May 1981 289

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6502

MICROPROCESSOR

IRQ 4

+ 5V A

PIN 30 FROM EACH APPLE PERIPHERAL SLOT

■3.3K

SLOTO

SLOTl

SLOT 7

Figure 3: The 6502 IRQ signal and the Apple II peripheral slots. The IRQ signal is connected to pin 30 of each of the slots and is held high by the pull-up resistor shown. A maskable interrupt is generated if the peripheral card in any of the slots presents a low impedance to ground to its pin 30.

rupt-service routine itself must be written very carefully. It must, of course, perform whatever service you wish it to—such as printing a message on the console, ringing a bell, dialing a telephone, or turning on the furnace. But while it is doing these things, the service routine must not disturb any code used by the other routines stored in memory. The stacks should be in exactly the same state upon exit as they were when the service routine began.

5. The RTI instruction at the end of the service routine unstacks the status registers and program counter. This ensures that execution will continue from the point reached just before the arrival of the interrupt. Functionally, it is equivalent to:

Pop status register Pop program-counter low byte Pop program-counter high byte Execute next instruction

Maskable Interrupts

Pin number 4 on the 6502 chip is an input signal called the interrupt request, IRQ. This is a maskable interrupt. In the Apple II, IRQ is connected through the printed-circuit board to a pull-up resistor and to each of the eight I/O slots, as shown in figure 3.

This is the same scheme used for the NMI except that the interrupt request will not be accepted if the interrupt-disable bit, I, in the status register, P, is set (ie: contains a 1). As before, this interrupt scheme can be

better understood by considering the five aspects of interrupts.

1. Any external device can generate an interrupt request by driving pin 30 on any I/O slot to ground potential. Once again, the Apple II can have eight different interrupt sources, and they all may decide to fire at the same time.

2. The 6502 microprocessor will respond to this request only if the interrupt-disable bit, I, in the status register, P, is cleared (ie: bit I must be a 0). This is done by executing a CLI (clear interrupt-disable bit) instruction any time before the arrival of the interrupt request. However, the 6502 will completely ignore the request if bit I has been set by executing an SEI (set interrupt-disable bit) instruction before the arrival of the interrupt.

3. Once again, the microprocessor is unable to determine the source of the interrupt. If there is only one device capable of sending an IRQ signal, there is no problem. If more than one device can do this, the same factors apply that were discussed earlier in the section on the nonmaskable interrupt, and polling can be used to determine which device caused the IRQ.

4. If bit I has been cleared and the IRQ signal arrives at the 6502, the following actions occur:

Push program-counter high byte Push program-counter low byte Push status register Jump via hexadecimal FFFE

Text continued on page 294

290 May 1981 © BYTE Publications Inc

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Listing 1: Assembly-language routines to test maskable and nonmaskable interrupts. Routines RNMI and RIRQ print the messages "NMI" and "IRQ", respectively, 255 times when the appropriate interrupt is generated. The short routines at hexadecimal 352 (decimal 850) and hexadecimal 354 (decimal 852) are meant to be called from BASIC to enable and disable, respectively, the maskable interrupt. See the text for details on generating the interrupts necessary to test these routines.

03FB03FE

4C 00 03 21 03

0300

48

0301

8A

0302

48

0303

98

0304

48

0305

A2

FF

0307

A9

CE

0309

20

ED FD

030C

A9

CD

030E

20

ED FD

0311

A9

C9

0313

20

ED FD

0316

CA

0317

EO

00

0319

DO

EC

031B

68

031C

A8

031D

68

03 IE

AA

031F

68

0320

40

0321

48

0322

8A

0323

48

0324

98

0325

48

0326

A2

FF

0328

A9

C9

032A

20

ED FD

032D

A9

D2

032F

20

ED FD

0332

A9

Dl

0334

20

ED FD

0337

CA

0338

EO

00

033A

DO

EC

033C

68

033D

A8

033E

68

033F

AA

0340

68

0341

40

0352

58

0353

60

0354

78

0335

60

SYMBOL TABLE

RNMI

0300

LI

L2

0328

1000 1010 1020 1030 1040 1050 1060 1070 1080 1090 1100 1110 1120 1130 1140 1150 1160 1170 1180 1190 1200 1210 1220 1230 1240 1250 1260 1270 1280 1290 1300 1310 1320 1330 1340 1350 1360 1370 1380 1390 1400 1410 1420 1430 1440 1450 1460 1470 1480 1490 1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610 1620 1630 1640 1650 1660 1670

•TEST OF INTERRUPT SYSTEM

RNMI

LI

.OR

$3FB

IMP

RNMI

.DA

RIRQ

.OR * * • * *

$300 ************

***•

ROUTINE

FOR NMI ********

*♦ * • *

............

PHA

SAVE REGISTERS

TXA

PHA

TYA

PHA

LDX

#$FF

LDA

WOE

PRINT "N"

JSR

$FDED

LDA

«CD

PRINT "M"

JSR

$FDED

LDA

§$C9

PRINT "I"

JSR

$FDED

DEX

CPX

10

BNE

LI

PLA

RESTORE REGISTERS

TAY

PLA

TAX

PLA

RTI

GO BACK

tt * t *.4* t ****** t *****.**** Hi *

* ** * * *****

ROUTINE FOR IRQ "***

RIRQ

L2

PHA TXA PHA TYA PHA

LDX #$FF

LDA

JSR

LDA

JSR

LDA

JSR

DEX

CPX

BNE

PLA

TAY

PLA

TAX

PLA

RTI

#$C9

$FDED

#$D2

$FDED

#$D1

$FDED

#0 L2

SAVE REGISTERS

PRINT "I" PRINT "R" PRINT "Q"

RESTORE REGISTERS

GO BACK

******************

"' ROUTINES FOR BASIC *•••••*

.OR CLI RTS SEI RTS .EN

850

ENABLE INTERRUPTS DISABLE INTERRUPTS

0307 RIRQ 0321

Circle 15 on inquiry card.

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Text continued from page 290: As before, the program counter and the status register are placed on the stack, and the processor executes an indirect jump via hexadecimal location FFFE. This is again a ROM area in the Apple II and has been set by Apple Computer Inc to the value hexadecimal FA86 (or FA40 in the autostart version), which is an address in ROM. Thus, the processor starts executing at location FA86 (or FA40), where it finds the following instructions (a "$" indicates a hexadecimal address):

STA$45 PLA

PHA

ASL A ASL A ASL A

BMI $FA92 or BMI $FA4C JMP ($03FE)

This section of code stores the accumulator at hexadecimal location 45 in page zero and checks to see if the fourth bit in the status register, the "break" bit B, is high or not. An interrupt request, IRQ, always forces this bit low, so the BMI instruction never succeeds and finally the indirect jump, JMP ($03FE), is encountered. The hexadecimal address 03FE is in programmable memory, and the writer of the service routine must place the address of the routine here. Note that this is somewhat different from the way in which the NMI request is routed. For the IRQ interrupts, the address of the service routine rather than a jump instruction including an address must be stored in the 2 bytes, hexadecimal 03FE and 03FF. Also, remember that the lower byte of the 2-byte address must be stored first.

As before, the registers are usually stacked first, although this time the accumulator can be left alone, since it has already been stored at hexadecimal location 45 by the program in ROM. Then the interrupt service is performed, the registers are restored, and, finally, an RTI is executed.

5. The processor returns to its original program after it encounters the RTI. As before, this instruction will;

Pop status register Pop program-counter low byte Pop program-counter high byte Execute next instruction

In principle, any program in any language can be interrupted by an external signal, and the interrupts can be serviced using the techniques described above. In microprocessor systems such as the Apple II, the interrupted program is usually a BASIC program, and the interrupt-service routines are usually written in assembly language. An example of such a service routine is shown in listing 1. It is assumed that there is only one device capable of generating an interrupt, that the service to be performed consists only of writing a message to the console, and that interrupts will not interrupt themselves.

To test this routine, a BASIC program should be written and executed. When you wish to enable the IRQ signal from your BASIC program, it is only necessary to execute:

CALL 850

and when you wish to disable the IRQ, all you have to do is:

CALL 852

If you do not have any device in your I/O slots capable of generating an interrupt request, you can easily make one by bending a resistor with a pair of long leads so that the leads are about one-half inch apart. A 100-ohm resistor works well. Then very carefully connect pin 29 (for the NMI) or pin 30 (for the IRQ) through the resistor to the ground pin (pin 26) on any of the I/O slots. This technique is crude but effective, and will generate the interrupt request whenever you wish. The NMI signal will always set the interrupt system in motion, but the IRQ signal will be accepted only if you have executed the BASIC instruction CALL 850.

Once you have mastered the fundamentals of interrupt handling, the number of interrupts that can be serviced and the complexity of the service are limited only by the speed of the interrupting devices and ingenuity of the servicing programs. ■

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3 microsecond conversion rate 1 parallel output port

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(216)382-7599 464-7410

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Circle 401 on Inquiry card.

BYTE May 1981 295

[FOR THE APPLE

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Digital Plotting with the Apple II Computer

Dr Richard C Hallgren Department of Biomechanics Michigan State University East Lansing MI 48824

The first attempts to use personal computers in the research laboratory have met with considerable success. Not only are these machines functioning as computational tools, they are also being used with custom interface circuits to digitize analog signals and to process data using routines such as the fast Fourier transform (see "Fast Fourier Transforms on Your Home Computer" by W D Stanley and S J Peterson, on page 14 of the December 1978 BYTE).

In dealing with complex, timedependent waveforms and their spectrums, it is desirable to display the data as a function of either time or

frequency. Plotting is possible with a data terminal such as the DECwriter II, but such methods are lacking when high-resolution plotting is required. The Hiplot digital plotter, manufactured by fiouston Instrument, gives the small-system user a cost-effective means of obtaining high-quality digital plots. The plotter uses an 8V2by 11-inch sheet of paper and allows plotting within a 7- by 10-inch boundary. Reversible stepper motors are used to give bidirectional steps of either 200 or 100 steps per inch, amounting to a resolution of 0.005 or 0.01 inches per step. An RS-232C serial interface is a standard feature, which makes connecting the plotter to a computer an easy task.

The Hiplot accepts data in an RS232C format consisting of 1 start bit, 8 data bits, and 2 stop bits. Since the computer manipulates 8 bits of

RS-232 TO HIPLOT

TO STEP SIZE SELECT HIPLOT

0

-12V

TTL IN FROM

PIN #15 GAME O

1/0 CONNECTOR

+12 V

" t

V

V+

1

1

DS14S8

A

B

Z

GROUND

STEP SIZE SELECT -<□ PIN #14 GAME 1/0 CONNECTOR

GND

-12V

+ 12V

APPLE

POWER SUPPLY

Figure 1: Schematic of Apple II TTL (transistor-transistor logic) to RS-232C interface utilizing only one line-driver integrated circuit, a DSi488.

296 May 1981 © BYTE Publications Inc

I

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BYTE May 1981 297

Circle 81 on inquiry card i

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298 May 1981 © BYTE PublicaHons Inc

8000

T nv

1 ft

8003—

HO

rtin

0 a V e ua^o. Dy uG

8004—

BO

05

BCS

?800B

8006—

nU

on

liDA

$C059

8009—

\jj

y 0\J\JCt

800b

AD

58

CO

LDA

SC05S

rii 1 "f" ni it* a Yna y*V

800E

A9

03

LDA

#$03

8010

48

PHA

8011

A9

04

LDA

#$04

8013

4A

LSR

Delay

8014

90

FD

BCC

$8013

8016

68

PLA

8017

E9

01

SBC

8019

rin

UKl

F5

alNci

o\j±a

PLA

Get data byte

flm r—

OUXV

ROR

Rotate into carry bit

OUXD—

88

DEY

Decrement bit count

801E

DO

E3

BNE

9 oUU J

Jujnp i f mo re da ta.

8020—

no

LDY

ff 9UZ

2 stop bits

8022

AD

38

CO

T na

Output a inar'}^

8025

A9

03

8027

48

PHA

8028

A9

04

LDA

802A

4A

LSR

Delay

802B

90

FD

BCC

B02D

68

PLA

802E

E9

01

SBC

#$01

8030

DO

F5

BNE

S8027

8032

88

DEY

Decrement bit count

8033

DO

ED

BNE

$8022

Jump if more stop bits

8035

60

RTS

Listing 1: 6502 machine-language routine to perform functions of a UART (universal asynchronous receiver/transmitter) for transmitting RS-232C serial data through the hardware modification.

parallel data at a time, we need a method to convert the parallel data to serial data. I decided to implement this conversion in software, instead of using a UART (universal asynchronous receiver/transmitter) to keep the system simple. The only things required are the software routine and a line driver to shift the TTL (transistor-transistor logic) voltage-level output from the Apple II to RS-232C levels for the Hiplot. A DS1488 quad line driver integrated circuit (see figure 1) is mounted on an Apple Hobby/Prototyping board and inserted into expansion slot 6 on the Apple motherboard. The Apple writes data to the line driver by toggling the latch circuit connected to the Apple game-I/O port. Accessing hexadecimal address C059 ("LDA $C059" in listing 1) causes a 1 to be transmitted. Accessing hexadecimal address C058 ("LDA $C058" in listing 1) causes a 0 to be transmitted. (In RS-232C communications, any voltage between -1-5 V and +15 Vis called a space and represents a "high" signal or a digital 0; any voltage between — 5 V and —15 V is called a mark and represents a "low" signal or a digital 1.)

Figure 2 on page 300 shows the flowchart for the software routine that replaces the UART; listing 1 (above) shows the program with comments. To reduce the plotting time to a minimum, I decided to operate the Hiplot at its maximum data rate of 9600 bps (bits per second). Executing the output routine loads the Y register with a count of nine and clears the carry bit. The routine then writes a mark (a digital 1 or a low signal) if the carry bit is cleared, or a space (the opposite of mark) if the carry bit is set, and loops for a time period equal to the time spacing between bits. The routine then shifts the data so the most significant bit goes into the carry bit and checks to see if all the data bits have been sent. If not, it loops to process the next bit. Otherwise, it transmits 2 stop bits and returns to the calling program.

Getting to the point where data can be transferred from the Apple to the Hiplot is only the first part of using the plotter. Since the plotter comes with no software, it is necessary to write routines which will generate axis systems and, if desired, alphanumeric characters.

Text continued on page 314

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5.75

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4.50

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4.50

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4,50

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4,50

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4.50

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4;50

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4;50

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100

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74LS42 .95

74LS47 1.15

74LS4B 1.15

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74LS73 .49

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74LSe3 .95

74LS85 1.25

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74LS90 .79

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74LS123 1,05

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74LS126 -70

74LS132 .95

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74LS13d .85

74LS148 1.75

74LS151 .79

74LS152 .79

74LSI53 79

74LS154 2.05

74LS157 1.15

74LS158 1.15

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74LS161 .85

74LS162 85

74LS163 95

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74LS221 .95

74LS240 1.05

7dLS241 1.05

74LS242 1.45

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74LS244 1.05

74LS245 2.15

74LS251 1.29

74LS253 .99

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74LS257 1,15

74LS258 1.15

74LS260 .95

74LS261 2.49

74LS266 .65

74LS273 1.65

74LS283 1.05

74LS365 .85

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74LS367 .85

74LS36a 85

74LS373 1.65

74LS374 1,45

74LS375 .99

74LS377 1.15

74LS3e6 .59

74LS390 1.75

74LS393 1.75

81LS95 1.35

81LS06 1.35

81LS97 1.35

81LS98 1.35

4000 CMOS

Part # Price

4000 .35

4001 .35

4002 35

4006 1 05

4007 .35

4015 4016 4017 4018

4022 4023 4024 4025 4026 4027 4028 4029 4030 4034 4035 4040 4041 4042 4043 4044 4046 4047

4052 4053 4060 4066

4072 4073 4075 4076 4077 4078 4081 4082 4093 4503 450B 4510

4515 4516 4518 4519 4520 4526 4527 4528

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BYTE May 1981 299

circle 266 on Inquiry card. /

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c

CONVERT PARALLEL TO SERIAL

3

LOAD Y REGISTER, CLEAR CARRY

SAVE DATA BIT

OUTPUT

SPACE

DELAy ONE BIT TIME

ROTATE

NEXT

DATA BIT TO

CARRY

YES

RESTORE REGISTERS

Figure 2: Flowchart for machine-language software UART in listing 1.

Listing 2: Machine-code command generator to select a specified plotter command

before calling the UART subroutine.

8038

48

PHA

8039

08

PHP

803A

A9

70

LDA

803C

20

00

80

, JSR

803F

28

PLP

8040

68

PLA

8041

60

RTS

8042

48

PHA

8043

08

PHP

8044

A9

71

LDA

8046

4C

3C

80

JMP

8049

48

PHA

804A

08

PHP

804B

A9

72

LDA

8040

4C

3C

80

JMP

8050

48

PHA

8051

08

PHP

8052

A9

73

LDA

8054

4C

3C

80

JMP

8057

48

PHA

8058

08

PHP

8059

A9

74

LDA

805B

4C

3C

80

JMP

805E

48

PHA

805F

08

PHP

8060

A9

75

LDA

8062

4C

3C

80

JMP

8065

48

PHA

8066

08

PHP

#$70 $8000

#$71 S8Q3C

#■$72 #B03C

#$73 $803C

#$74 $803C

#$75 $803C

Save accumulator Save processor status Output 'p'

Jump to parallel to serial conversiorj Restore processor status Restore accumulator Return •

Output 'q'

Output 'r'

Output 's'

Output 't'

Output 'u'

Listing 2 continued on page 302

300 May 1981 © BYTE Publications Inc

32K Board Pictured Above

Why Not the Best?

From The Dynamic RAM Company.

2MHz 4MHz

16K—$249 $259

32K—$375 $395

48K—$500 $530

64K—$625 $665

We have now been shipping our 2MHz dynamic RAIVI boards for over two years. Hundreds of 4IVIHZ boards have been going out every month since early 1979. Our reliability is proven in the thousands of systems which contain our board. Many qualityminded systems houses across the country and overseas are using our boards for their equipment.

Our prices still beat all. Despite rising 16K memory chip prices (at least from reputable suppliers), Central Data continues to give you the best buy in memory today. Nobody offers a board with a capacity of 64K, assembled, tested, and guaranteed for a full year at the price we do.

circle 65 on Inquiry card.

Deselect around PROMs. Our boards have the important deselect feature which lets you overlap any fixed memory in your system with no interference.

Our features make the board easily used and expanded. You address our boards on 16K boundaries with mini-jumps (small shorting plugs that slide over wirewrap pins) near the top of the board for easy access. If you want to expand your board after you have purchased it, ail that you need to do is add memory. We can supply you with expansion pacl<ages ($150-2MHz, $160-4MHz) which include eight RAMs that you can depend on as well as two mini-jumps for addressing. And of course, our board never generates wait states.

Low power consumption keeps your computer running cool and reliable. The total power consumption of our 16K board is

typically less than 4 watts ( + 8V @ 300ma, +16V ® 150ma and

-16V @ 20ma). Boards with additional memory typically increase power consumption only 1 watt per 16K!

Standard S-100 Interface. Our board is designed to interface with any standard S-100 CPU. All of the timing of the board is independent of the processor chip, and the board is set up for different processors by changing two plugs on the board.

Call or write us today. That will guarantee a fast response with more information on the board. Or make an order — you'll probably have the board in two weeks! If you're interested, also ask for a catalog on our Z8000 16-blt processor board designed for the iVIULTIBUS. All of these products are available to your local dealer, also.

Central Data Corporation, 713 Edgebrook Drive, PO Box 2530, Station A, Champaign, IL 61820. (217) 359-8010

Central Data

BYTE May 1981 301

NO FRILLS! NO GIMMICKS! JUST GREAT

DISCOUNTS

MAIL ORDER ONLY

ATARI 800

Personal Computer

System

$79900

NORTHSTAR

Horizon II32K

Horizon 11 Quad

Horizon II64K

Horizon Quad 64K

234900 279900 299900 339900

TELEVIDEO

912

74900 79900

HAZELTINE

1420

1500

1510

1520

79500 84900 104900

122900

OKIDATA

MicrolineSO . ,

55900

SOROC Technology

IQ 120 69900

IQ 140 99900

CROMEMCO

System 3

Z2H

569500 799500

TELETYPE

43

Acoustic Coupler

94900 .17900

DECwrlter IV

LA34

97900

TEXAS INSTRUMENT

810 Multi Copy Impact Printer 149900

We'll meet or beat any advertised prices!

Most items in stocl< for immediate delivery.

Factory sealed cartons Full manulacturer's guarantee

DATA DISCOUNT CENTER

135-53 Nonhern Blvd., Flushing, N.Y. 11354

Visa • IVIaster Ctiarge • I^.Y.S. residents add SalesTax StiippingF.O.B. N.Y.

Phone Orders Call 212-895-5577

Listing 2 continued:

8067

A9

76

LDA

#$76

Output

'v

8069

4C

3C

80

JMP

$803C

806C

48

PHA

8060

08

PHP

806E

A9

77

LDA

#$77

Output

'w

8070

4C

3C

80

JMP

$ao3c

8073

48

PHA

8074

08

PHP

8075

A9

79

LDA

#$79

Output

'y

8077

4C

3C

80

JMP

#803C

807A

48

PHA

807B

08

PHP

807C

A9

7A

LDA

it$7A

Output

'z

807E

4C

3C

80

JMP

$803C

Listing 3: BASIC program to produce a plot of the voltage across a charging capacitor.

10 HEM MAIN PROGRAM

12 HOME : VTAB 12

14 PRINT "POSITION PEN IN LOWER LEFT HAND"

16 PRINT "CORNER. PRESS ANY KEY TO CONTINUE."

18 GET A$

19 HOME

20 GOSUB 1000 REM DRAW X,y AXIS 30 REM EXPONENTIAL RISE

32 POKE - 16293,0 REM SET RESOLUTION TO 200 POINTS PER INCH

34 Z = 0

36 CALL - 32646: FOR I = 0 TO 10: NEXT I REM PEN DOWN

38 FOR I = 0 TO 8.99 STEP .005

40 V = 5 * (1 - EXP ( - I)) REM FIND CAPACITOR .VOLTAGE

42 K = INT (200 * V)

44 IF K - Z = 0 THEN GOTO 90 REM NO CHANGE IN PREVIOUS POTENTIAL

46 IF K - Z < 0 THEN GOTO 50 REM POTENTIAL IS DECREASING

48 FOR J = 1 TO (K - 2) REM POTENTIAL IS INCREASING

50 CALL - 82712 REM MOVE IN -l-Y DIRECTION

52 NEXT J

54 GOTO 70

60 FOR J = 1 TO (Z - K)

62 CALL - 32681 REM MOVE IN -Y DIRECTION

64 NEXT J

70 Z = K

90 CALL - 32695 REM MOVE IN -^X DIRECTION

92 NEXT I

94 CALL - 32653 REM PEN UP

99 END

300 REM "1"

301 CALL - 32653: FOR I = 1 TO 8: CALL - 32674: Next I.

302 CALL - 32646

304 FOR I = 1 TO 8: CALL - 32702: NEXT I

306 FOR I = 1 TO 26: CALL - 32681: NEXT I

308 CALL - 32653

310 FOR I = 1 TO 8: CALL - 32667: NEXT I

312 CALL - 32646

314 FOR I = 1 TO 16: CALL - 32695: NEXT I

316 CALL - 32653

317 FOR I = 1 TO 8:

318 FOR I = 1 TO 26: CALL - 32712: NEXT I

319 RETURN

320 REM "2"

321 CALL - 32653: FOR I = 1 TO 8: CALL - 32667: NEXT I

322 CALL - 32646

324

FOR

I

1

TO

16:

CALL

- 32695:

NEXT

I

326

FOR

I

1

TO

13:

CALL

- 32681:

NEXT

I

328

FOR

I

1

TO

16:

CALL

- 32667:

NEXT

I

330

FOR

I

1

TO

13:

CALL

- 32681:

NEXT

I

332

FOR

I

1

TO

16:

CALL

- 32695:

NEXT

I

334 CALL - 32653

336 FOR I = 1 TO 8: CALL - 32667: NEXT I

337 FOR I = 1 TO 26: CALL - 32712: NEXT I 339 RETURN

Listing 3 continued on page 304

302 May 1981 © BYTE Publications Inc

OUR TIMING CONTROL UNIT HELPS YOUR COMPUTER KEEP SCORE OF TIME AND DATE.

Power-up or power-down, your computer always knows the time, exactly, with Digital Pathway's Timing Control Unit (TCU). Even during extended power interruptions. Rechargeable battery support makes our TCU immune from power failure of any kind. For as long as three months. And an on-board crystal-controlled oscillator ensures supreme accuracy.

No matter what model computer you have, you'll find our TCUs offer many features that make living with computer timeouts less complicated. And some models can even be set to initiate an interrupt at a chosen date and time. Or at specified intervals.

Find out how we can help make your time more productive. Call or write Digital Pathways today for more information at 1260 L'Avenida, Mountain View, CA 94043. Telephone (415) 969-7600. TWX: 910-379-5034.

*PDP-11 and LSI-11/2 are registered trademarks of Digital Equipment Corp. Others

iisiea are traaemarKs,

respectively, of Intel Corp., Motorola Inc., Hew Lockheed Corp. and Computer Automation Inc.

* PDP-11

*LSI-11/2 "Multi-Bus *EXORcisor *HP 2100 "Lockheed SUE "Naked Mini Any Model Computer (RS-232/20mA)

Circle 128 on inquiry card.

Germany: (089) 60 60 7

Circle 36 on inquiry card.

*99

4r For The

GENERAL

The Micro Computer General 85

FOR USE IN:

* OEM Industry • Laboratory

• University • Home

The General is a 4.5"x 6.5" single board micro computer, ideal for industrial control applications as well as for dedicated test monitoring systems, communication subsystems, small scale data processing and front end processing. Through its advanced design, it is adaptable for data logging, data acquisition, prototyplngcand experimenting. Its compact size allows for easy Integration Into already existing equipment, and provides an excellent nucleus when designing new products.

User communication is accomplished through the General's "Expedltor" system monitor. The Expediter resides in a 2K EPROM, and features 15 commands and 18 utility routines to facilitate program development. An Instructional user's manual Is provided with every unit.

HARDWARE FEATURES

' 8065 CPU (100% software compatible with 8080)

* 2K bytes of EPROM (containing ttie EXPEDITOR system monitor) expandable on board to 4K bytes.

* EIA serial port (50-19.2K baud)

* 22 programmable I/O lines

* Software controlled 14 bit counter and timer ' 3 priority Interrupts

* 2 non-maskable Interrupts

' 2S6 bytes of programmable memory expandable cn board to 2K bytes of either STATIC Ram or CMOS Ram

* On board data bus buffers for system expansion

* Parallel I/O ports available at on-boanl sockets

* Address, data and control bus available at edge connector In addition to 6 spare pins.

* Ample on-board prototyping space

* Small size (4.5" x 6.S")

SOFTWARE FEATURES

EXPEDITOR—2K SYSTEM MONITOR

* 1S System commands (Substitute, Move, Display, Fill, Kill echo. Examine registers, Insert, String search, Assemble code, Disassemble code. Read, Write, Binary load, ASCII load)

* 18 utility routines Including Terminal I/O routines. Test and compare routines. Code check or convert

* Download commands. Read, Binary load. ASCII load will give the user three different data formats of downloading data directly into the Ram of the computer. This will allow the user to develop his software on a larger computer, then use the MCG-85 as the "execution vehicle" of software.

* Automatic baud rate selection

HARDWARE ft POWER REQUIREMENTS

The Qaneral requires -fS ±12 volts power supply (±12 volts required only lor RS232 Transmitter Interface) and a Terminal for complete system operation (Hex Keypad version will be available shortly). The power requirements are +s Volts at SOO MA and -4-12 -12 at 50 MA.

PRICING INFORMATION

The General MCG-85 (kit) $ 99.00

The General MCG-85

(assembled and tested) 135.00

2K Expansion ROM 15.00

2K CMOS RAM 50.00

2K Expansion RAM 20.00

3 Voltage Power Supply 59.00

Edge Connector 6.00

Data Bus Buffer Expansion 10.00

Line Assembler (on 2716 EPROM).. 35.00 Disassembler (on 2716 EPROM).... 35.00 Expedltor Monitor Listings

(Monitor Form) 29.00

Send cheek or money order, or charge to VISA/MASTER CHARGE card number. Add $4.00 tor shipping and handling. COD fee extra. New York residents add 8% sales tax.

' In kit form, single quantity. Introductory offer good till June 30, 1981. Dealer Inquiries Invited.

ATLANTIS COMPUTERS

Division of Atlantis Computerized Services

34-13 30th Avenue, Astoria, NY 11103 (212) 728-6700

Listing 3 continued: 340 REM "3" CALL CALL

341 342 344 346 348 350 352 354 356 357 358 359 360 361 362 364 366 368 372 374 376 377 378 379 380 381 382 384 386 388 390 392 394 396 397 399 400 401 402 404 406 408 410 412 414 415 416 420 422 424 426 428 430 432 434 436 439 440 442 444 445 446 448 450 452 454 456 457 458 460 462 464 469

FOR FOR FOR FOR FOR FOR CALL FOR I FOR I RETURN REM "4" CALL CALL FOR I FOR I CALL FOR I CALL FOR I CALL FOR I FOR I REM CALL CALL

32653: 32646 1 TO 16 1 TO 13 1 TO 16 1 TO 16 1 TO 13 1 TO 16 32653 1 TO 8: 1 TO 26

FOR I = 1 TO 8: CALL

32667: NEXT I

CALL

- 32695:

NEXT

I

CALL

- 32681:

NEXT

1

CALL

- 32667:

NEXT

I

CALL

- 32695:

NEXT

I

CALL

- 32681:

NEXT

I

CALL

- 32667:

NEXT

1

CALL

32695: - 32712:

NEXT I NEXT I

"5"

FOR FOR FOR FOR FOR

CALL FOR I = FOR I = RETURN REM "6 CALL CALL FOR I = FOR I = FOR I = EOR I = CALL FOR I = FOR I = RETURN REM "7" CALL • FOR I i CALL ■ FOR I ■ FOR I ■ CALL • FOR I ■■ FOR I • RETURN

32653: 32646 1 TO 13: 1 TO 16:

32653 1 TO 13; 32646 1 TO 26; 32653 1 TO 261 1 TO 8:

32653: 32646 1 TO 16 1 TO

FOR I = 1 TO 8: CALL

32667: NEXT I

CALL CALL

CALL CALL

CALL CALL

- 32681: NEXT I ■- 32695: NEXT I

- 32712

NEXT I

- 32681: NEXT I

- 32712: NEXT I

- 32667: NEXT I: RETURN

FOR I = 1 TO 8: CALL - 32695: NEXT I

13 TO 16 TO 14 16

1 TO 32653 1 TO 26 1 TO 8:

32653: 32646: 1 TO 26 1 TO 16 1 TO 13 1 TO 16 32653 1 TO 13 1 TO 8:

32653 1 TO 8: 32646: 1 TO 16i 1 TO 26i 32653 1 TO 26; 1 TO 8:

CALL

- 32667

NEXT

I

CALL

- 32681

NEXT

I

CALL

- 32695

NEXT

I

CALL

- 32681

NEXT

I

CALL

- 32667

NEXT 1

CALL

- 32712

NEXT

1

CALL -. 32695: NEXT I

REM CALL ■ FOR I ■■ CALL ■ FOR I •■ FOR I ■ FOR I : FOR I CALL ■ FOR I CALL ■ FOR I CALL ■ FOR I FOR I : RETURN

8"

32653 1 TO 8: 32646: 1 TO 16

1 TO 26 1 TO 16 1 TO 26 32653 1 TO 13 32646 1 TO 16 32653 1 TO 8: 1 TO 13

FOR I = FOR I = CALL CALL CALL CALL

CALL CALL

CALL FOR I = CALL CALL

CALL CALL

CALL FOR I = CALL CALL CALL CALL

CALL

CALL

CALL CALL

TO 8: TO 10 32681 ■32695 32712 32667

CALL NEXT NEXT NEXT NEXT NEXT

32667:

NEXT I

- 32712; NEXT I - 32695: NEXT I

- 32667: NEXT I 0 TO 10: NEXT I

- 32695: NEXT I

- 32681: NEXT I

- 32712: NEXT I

- 32567: NEXT I

- 32695: 0 TO 10

- 32667

- 32681

- 32695

- 32712

NEXT I NEXT NEXT NEXT NEXT NEXT

- 32681: NEXT I

- 32667: NEXT I

- 32695: NEXT I

- 32712: NEXT I

Listing 3 continued on page 306

Let onG)mpttting be yoar guide to personal comptttinl.

RnaUy, there is a

magazine that

sp^iks to the be^tmer.

onCompittif^ is the new McGrawHUI quarterly that tells what's ahead —

without talking over your head — in the 1980's with personal computers.

onCompttting puts you on target with all the applications that go beyond your imegination.

□ Personal computers in the home.

□ Classrooms.

□ They bring computer mu^C'

□ Electronic mail.

□ Robots.

□ They manage your personalized investment.

□ The list goes on and on in onCompatliig. If you're a beginner with personal

computers, get the most understood magazine on computers, onComputii^. And even if you're an experienced computer user, onComputing has the information you need in today's fastgrowing personal computer market.

onComputing

i:nik

Get onto onG»npa&ig. CaU 800-258-5485.

7B51

onComptstlng SubsoipUon Dept. P.O. Box 307, Martinsville, NJ 08836 DOMESTIC subscription rate:

□ U.S. 1 vr. (4 issues) @ $8.50 □ Canada & Mexico, 1 yr. (4 issues) @ $10.00 3

FOREIGN (to expedite service, please remit in U.S. funds drawn on a U.S. bank) ™

□ Europe (and all other countries, except above), 1 Yr. @ S 12.00 — surface deliveiy. |

□ BUI Visa □ Bill Master Charge □ ffill me (North America only) |

Card Number

Expiratior\

Signature

Name (please print)

Street/Apartment Number

City

State/Provincc/CountrY' Code

©onComputing. Inc. 1981

COMPUTER FORMS KIT

with continuous business forms for smaii computer systems

Each kit contains samples, programming guides, flyers, prices and order forms for checks, invoices, statements, envelopes, stock paper and labels to fit almost every computer system.

• Available in quantities of 500,1,000, 2,000 4,000, 6,000

• Low Prices (500 checks only $32.50)

ZJ

• FAST SERVICE — It is our policy to ship within 6 working days following our receipt of your order.

• MONEY BACK GUARANTEE — If for any reason you are not completely satisfied, your money will be promptly refunded.

Fast Service by mall or.. .PHONE TOLL FREE 1 + 800-225-9550

Mass. residents 1 + 800-922-8560 8:30 a.m. to 5:00 p.m. Eastern Time Monday — Friday

I Please Ship FREE Kit To: I Name

I

CODE 460

Company

I

Street

City, State and Zip

Phone

Computer make & model

— - Cor^ter R>rms ^

78 HolUsStreeL,Groton.Mass. 01450

A divlslon of New England Business Service, Inc.

Listing 3 continued:

430

r<i;M "9"

482

CALL

32653

483

Ir'OR I =

1 TO 8:

CALL

32667:

NEXT I

484

CALL

32C4C): FOR I =

0 TO 10

NEXT I

485

FOR I =

1 TO 16:

CALL

- 32695

NEXT I

48G

FOK I =

1 TO 26:

CALL

- 32681

NEXT I

487

CALL

32653

488

FOR I =

1 TO 13:

CALL

- 32712

NEXT I

489

CALL

32646

490

FOR I =

1 TO 16:

CALL

- 32667

NEXT I

492

FOR I =

1 TO 13:

CALL

- 32712

NEXT I

493

CALL

32G53

494

FOR I =

1 TO 8:

CALL

32695:

NEXT I

499

RETURN

500

REM "0

502

CALL

32653

504

FOR I =

1 TO 8:

CALL - 32695:

NE XT I

506

CALL

32646: FOR I =

0 TO 10

NEXT I

508

FOR I =

1 TO 16:

CALL

- 32667

NEXT I

510

FOR 1 =

i TO 26:

CALL

- 32681

NEXT I

512

FOR I =

1 TO 16:

CALL

- 32695

NEXT I

514

FOR I =

1 TO 26;

CALL

- 32712

NEXT I

516

CALL

32653

518

FOR I =

1 TO 8:

CALL - 32667:

NEXT I

519

RETURN

999

END

1000

REM X

AXIS

1010

pom

- 16294,0:

CALL

- 32653

1012

FOR I

= 1 TO 50:

CALL

- 32712

NEXT I

1014

CALL

- 32646:

FOR I =

= 0 TO 10

NEXT 1

1016

FOR I

= 1 TO 1000: CALL - 34695: NEXT

1018

CALL

- 32653

1100

RF.M y.

AXIS SCALE

1110

FOR I

= 1 TO 20:

CALL

- J2712

NEXT I

1112

CALL

- 32646:

FOR I =

- 0 TO 10

NEXT I

1114

FOR I

= 1 TO 40:

CALL

- 32681

NEXT I

1116

CALI.

- 32653

1118

FOR I

= 1 TO 5:

CALL

- 32681

NEXT I

1120

POKi:

- 16293,0

1122

GOSUB

480

1124

POKE

- 16294,0

1126

FOR I

= 1 TO 50:

CALL

- 32667

NEXT I

1128

FOR I

= 1 TO 38:

CALL

- 32712

NEXT I

1130

CALL

- 32646:

FOR I =

= 0 TO 10

NEXT I

1132

FOR I

= 1 TO 26:

CALL

- 32681

NEXT I

1134

CALL

- 32653

1146

FOR I

= 1 TO 50:

CALL

- 32667

NEXT I

1148

FOR I

= 1 TO 33:

CALL

- 32712

NEXT I

1150

CALL

- 32646:

FOR I = 0 TO 10

NEXT I

1152

FOR I

= 1 TO 40:

CALL

- 32681

NEXT I

1154

CALL

- 32653

1156

FOR I

= 1 TO 5:

CALL

- 32681:

NEXT I

1158

POKE

- 16293,0

1160

GOSUB

440

1162

POKE

- 16294,0

1164

FOR I

= 1 TO 50:

CALL

- 32667: NEXT I

1166

FOR I

= 1 TO 38:

CALL

- 32712

: NEXT I

1168

CALL

- 32646:

FOR I = 0 TO 10

. NEXT I

1170

FOR I

= 1 TO 26:

CALL

- 32681: NEXT I

X172

CALL

- 32653

1174

FOR I

= 1 TO 50;

CALL

- 32667

NEXT I

1176

FOR I

= 1 TO 33:

CALL

- 32712

NEXT I

1178

CALL

- 32646:

FOR 1 = 0 TO 10

: NEXT I

1180

FOR I

= 1 TO 40:

CALL

- 32681

s NE XT I

1182

CALL

- 32643

1184

FOR I

= 1 TO 5:

CALL

- 32681

NEXT I

1186

POKE

- 16293,0

1188

GOSUB

420

1190

POKE

- 16294,0

1192

FOR I

= 1 TO 50:

CALL

- 32667

: NEXT I

1194

FOR I

= 1 TO 38:

CALL

- 32712

: NEXT I

1196

CALL

- 32646;

FOR I =

= 0 TO 10

NEXT I

1198

FOR I

= 1 TO 26:

CALL

- 32681

. NEXT I

1199

CALL

- 32653

Listing 3 continued on

306 Maiy im © BYTE Piiblkatiora he Circle 280 on inquiry card.

''By the time we get out of this traffic, my 6-month auto policy will be up for renewal.

And they may raise my rate, too!'"

\

''6 months?

Next time, call GEICO and

get a 12-month policy.'

Unlike most companies, GEICO still offers the 12-month auto policy...a full year's coverage at a low rate. With a choice of convenient payment plans to fit your budget. Up to 9 payments if you wish.

And this is possible because GEICO tries to insure only good drivers. Good drivers are the best inflation-fighters around. You have fewer accidents. You cost us less. So you are one reason we can afford to charge you less.

"Good" doesn't mean "perfect." Even good drivers may occasionally have an accident. That doesn't necessarily bar you from GEICO...or from being renewed once you're a GEICO policyholder.

If you call, you'll talk directly to a GEICO sales insurance counselor, not a salesman. So there's no pressure. And no extra sales expense to inflate the cost.

GEICO has been saving money for good drivers since 19.S6. 'E)day, nearly 1,500,000 people are satisfied GEICO l)olicyholders. And that makes GEICO the 5th largest of the more than 1,000 stock companies insuring autos in the U.S.

GEICO has fast and efficient claim service with toll-free and collect-call telephone numbers throughout the U.S. So if you have to report an accident or loss, you can call our claim adjusters immediately. We also have

over 3,500 claim representatives countrywide to assist in handling your claim if necessary.

NOTE: While you're checking GEICO, why not find out about our rates for homeowner/renter and iioatowner coverage. And-even if you do not meet GEICO's auto policy standards—you may still obtain the same quauty auto coverage and service from our affiliate. Criterion Insurance Company, at somewhat higher rates. Criterion operates in the District of Columbia and every state except Massachusetts, New Jersey and South Carolina.

Where good drivers get the low rates they deserve.

Call toll-free 800-841-3000 (8 a.ni.-9 a.m. East Coast Time) In Georgia call toll-free 800-342-2800 or mail coupon. No obligation. No salesman will call.

Send to: GEICO & Affiliates, Consumer Information Services, GEICO Center, IVIacon, GA 31295

Name_

If student away at school, how many miles to school? miles,

Address

aty

-State

-Apt- =Zlp_

Employer

-= Ifrs..

Govt, or Military Grade

Location of car if different from address above: Car = 1: Oty

Car = 2: City

Car = 3; City

- Have you previously been insured with GEICO? □ Yes □ No

-State

_ State-State

Name of current insurance co..

- Month/Year Current Policy Expires

Ustall drivers

M or F

Relation

Age

Marital Status

Occupation

Yrs. lie.

Driver Training

% of Use of Cars = 1 =2 =3

Accidents in Past 5 Years"

Viola in P

3 Ye

ions ast

3r5'

License Suspension "

Yes

No

Yes

No

Yes

No

Yes

No

SELF

Year & iVIake

■Model (Nova, Granada, etc)

Body type: 2/4dr.sdn, hardtop, sta. wag

No. of cylinders

Est. Annual Mileage

Days per week driven to work or parking area

One way driving

distance

Is car used in business (except to/from job)?

If "yes" explain

CARl

CAR 2

CAR 3

°For accidents, vkilations, or license suspension, give dates and complete details, Including cost of damages, on a separate sheet. Check for Information on □ Homeowners/Renter's Insurance O-Boatowner's Insurance

684

GEICO and Affiliates. Corporate Headguartara: Wtashlngton, D.C. 20076

Circle 166 on inquiry card.

Not available in New Jersey or Massachusetts.

BYTE N4ay 1981 307

[}n(o)[La©"(S@[ji] insTrument

FROM COMPUTERS TO GO

A si« pen plotter option is now available lor shipment with the Houston Instrument DMP series of plotters. Now you can produce graphs or charts in black, red. blue, green, violet orange and optional brown. With the addition ol the $395 six pen option, the DMP-2 through the DMP-7 series of plotters, becomes the only line of multi color plotters starting under

si,aoo.

Digital plotters lor the Apple, Atari, PET. PMC-80, TRS-80 or other systems with RS-232C or Centronics data source.

8'.'! X 11"

DMP-2 DMP-3 DMP-4

STANDARD

$1085.00 S1250.00 $1385.00

6 COLOR

$1480.00 $1645.00 $1780.00

ll"xl7'

DMP-5 DMP-6 DMP-7

STANDARD

$1685.00 $1850.00 $1985.00

6 COLOR

$2080.00 $2245.00 $2380.00

The Houston Instrument HI PAD Digitizers lor the Apple, Atari, PET, PMC80, TRS-80 or other systems with RS-232C or Centronics data source. The HI PAD Digitizer is an input device that converts graphic information into

digital values. The HI PAD comes completely assembled and ready to use. with an RS-232C and parallel interface integrated lor convenient interlacing to your minicomputer or microcomputer based system It is priced at only S795 00

SOFTWARE TO GO

presents

THE EVANS BUSINESS SYSTEM; a user-definable data-management system emphasizing rapid access to individual records for the APPLE II. Requires 48K, 1 disk drive, ROM or RAM Applesoft, (written by Al Evans)

USE THE BUSINESS SYSTEM FOR:

Rolodex Emulation

Financial Records Real Estate Locator Grade Books

Catalogs

Lab Test Results

Bibliographies

Names and Addresses

Fantasy Game Characters Any Application Requiring Fast Cross-referenced Random Access to Formatted Information

RETRIEVAL TIME: Average less than 5 seconds for any of 1000 records. NUHflBER OF FIELDS: delined by user. RECORD LENGTH: Delined by user. FILE SIZE: Determined by record length and disk capacity. Keylield(s): Specified by user.

INTRODUCTORY OFFER

You can get the EVANS BUSINESS SYSTEM software package tor $99.95,

1 00 lor 1 flnmn rODV 'rrnrlitnhip tov*yarH<-. th*^ narkafo piirrbase.)

Listing

1200

1202

1204

1206

1208

1210

1212

1214

1216

1218

1220

1222

1224

1226

1228

1230

1232

1234

1236

1238

1240

1242

1244

1246

1248

1250

1252

1254

1256

1258

1260

1262

1264

1266

1268

1270

1272

1274

1276

1278

1280

1282

1284

1286

1288

1290

1292

1294

1296

1298

1300

1302

1304

1306

1308

1312

1314

1316

1318

1320

1322

1324

1326

1328

1330

1332

1334

133C

1338

1340

1342

1344

1346

1348

3 continued:

FOR I FOR I

CALL FOR I

CALL FOR I POKE

1 TO 50! 1 TO 33: 32646: 1 TO 40:

32653 1 TO 5: 16293,0

CALL CALL FOR I = CALL

- 32667:

- 32712: 0 TO 10:

- 32681:

NEXT NEXT NEXT NEXT

CALL - 32681: NEXT I

GOSUB 400

POKE FOR I FOR I CALL FOR I CALL FOR I FOR I CALL FOR I CALL FOR I POKE

16294,0 1 TO 50: 1 TO 38; 32646: 1 TO 26; 32653 1 TO 50; 1 TO 33; 32646: 1 TO 40; 32653 1 TO 5: 16293,0

CALL CALL FOR I = CALL

CALL CALL FOR I = CALL

- 32667

- 32712 0 TO 10

- 32681

- 32667

- 32712 0 TO 10

- 32681

NEXT I NEXT I NEXT I NEXT 1

NEXT I

NEXT I

NEXT I

NEXT I

CALL - 32681: NEXT I

GOSUB 380

POKE FOR 1 FOR I CALL FOR I CALL FOR I FOR I CALL FOR I CALL FOR I POKE

16294,0 1 TO 50: 1 TO 38: 32646: 1 TO 26; 32653 1 TO 50! 1 TO 33; 32646: 1 TO 40! 32653 1 TO 5: 16293,0

GOSUB 360

POKE FOR I FOR I CALL FOR I CALL FOR I FOR I CALL FOR I CALL FOR I POKE GOSUB POKE FOR I FOR I CALL FOR I FOR I FOR I CALL FOR I CALL For I POKE GOSUB 320 POKE FOR I FOR I CALL FOR I CALL FOR I FOR I CALL FOR I CALL

- 16294,0

= 1 TO 50 = 1 TO 38

- 32646: = 1 TO 26

- 32653 = 1 TO 50 = 1 TO 33

- 32646: = 1 TO 40

- 32653 = 1 TO 5:

- 12394,0 340

- 16294,0 = 1 TO 50 = 1 TO 38

- 32646: = 1 TO 26

- 1 TO 50 = 1 TO 3 3

- 3254C: = 1 TO 40

- 32653 = 1 TO 5:

- 16293,0

CALL CALL FOR I = CALL

CALL CALL FOR I = CALL

CALL

CALL CALL FOR I = CALL

CALL CALL FOR I = CALL

CALL

- 32667

- 32712 0 TO 10

- 32681

- 32667:

- 32712: 0 TO 10:

- 32681:

NEXT I NEXT I NEXT I NEXT I

NEXT NEXT NEXT NEXT

32681: NEXT I

- 32667

- 32667 0 TO 10

- 32681

- 32667

- 32712 0 TO 10

- 32681

NEXT I NEXT I NEXT I NEXT I

NEXT I NEXT I NEXT I NEXT I

32681: NEXT I

CALL

32667

NEXT

I

CALL

32712

NEXT

I

FOR 1=0

TO 10

NEXT

I

CALL

32681

NEXT

I

CALL

32667

NEXT

I

CALL

32712

NEXT

I

FOR 1=0

TO 10

NEXT

I

CALL

32681

NEXT

I

CALL - 32681: NEXT I

16294,0

1 TO 50:

CALL

32667:

NEXT

I

1 TO 38:

CALL

32712:

NEXT

I

32646:

FOR 1 =

0

TO 10:

NEXT

I

1 TO 26:

CALL

32681:

NEXT

I

32653

1 TO 50;

CALL

32667:

NEXT

I

1 TO 33;

CALL

32712;

NEXT

I

32646:

FOR I =

0

TO 10:

NEXT

I

1 TO 40:

CALL

32681:

NEXT

I

32653

Listing 3 continued on

COMPUTERS TO GO (a division of C.T.G Corp.) 2000 Guadalupe Austin, TX 78705 (51?) 472 8926 9A.M. 10 P.M., M. Sat. DEALER INQUIRIES INVITED

308 May IMl © BYTE Publications IxK

Circle 376 on inquiry card.

Circle 419 on Inquiry card.

COMPUTERS-TERMINALS-MODEMI

MODEMS AND COUPLERS

Connect your Apple, TRSSO or any other computer or terminal to the phone lines!

Penril

Penril 300/1200

Penril 300/1200—Bell 212A style $799

Bell 212A style. 1200 baud and 300 baud. Manual originate, auto-answer. Full duplex. RS232. Direct connect to phone lines via RJ11C standard extension phone voice Jack. 1 year warranty.

U.S. Robotics

USR-330A

Bell 103/113 style

USR-330D

Bell 103/113 style

USR-330D $339

Bell 103/113 style. 330 baud. Manual originate, autoanswer. Half/full duplex. RS232.1 year warranty. Direct connect to phone lines via RJ11C standard extension phone voice jack.

USR-330A $399

Same as USR-330D but includes auto-dlal capability.

U.S. Robotics The

Ptione Link

Acoustic

Modem

Bell 103/113 style $179

300 baud. Sleek, low profile. Originate and answer capability. Half/full duplex. Self-test. RS232. Light displays tor On, Carrier, Test, Send Data, Receive Data. 15 oz.

Perkln-Elmer Corporation

■Bantam 5508 .... $694 Compact. Silent. Upper/lower case. 80th col. wrap-around. Bell. Integrated nunnetic pad. Printer port. Transparent mode. Editing features. 1 Tabbing.

|k Bantam550E...$755

Same as 5508 plus ^^^^^^^gl^^^^H separate numeric key^HH^^^^^^^^^ pad and cursor keys.

Bantam 550S $879

Same as 550E plus block mode. 8 function keys, and protected fields, reverse video fields, half intensity fields, blinking fields,

550 Options

20mA Current Loop Interface $70

Non-Glare Screen $26

2ncl page of memory (550S only).. $100

Digital Equipment Corporation

DECVT100

DECVT10G ,,.$1668 Detachable keyboard. Separate numeric keypad with function keys. Business forms character set. Reverse video. Selectable double-size characters. Bidirectional smooth-scrolling. 80 cols or 132 cols. Split screen. Settable tabs. Line drawing graphic characters. Status line. Key-Click.

HARDCOPY TERMINALS

^' Teletype IModel 43

CRT'S

Perkin-Elmer Corporation

Superowl 1251

Perkln-Elmer Superowl 1251 $1564

Intelligent, editing CRT, Detachable keyboard, 32 fully programmable function keys. Intelligent printer part. Business forms character set. Block mode. Protected fields. Blinking fields. Numeric fields. Reverse video. Half Intensity. Polling. Down line loading of options. Remote control of all options by host computer. Settable tabs. Status'line. Separate numeric keypad. Transparent mode.

Teletype Corporation

Teletype Model 43 KSR wltti RS232 and Connector Cable $999

30 CPS. Dot matrix. 132 cols. True descenders on lower case. Excellent print quality for dot matrix printer. Pin

feed.

NEC Corporation NEC Splnwriter 5510 & 5520

5520 KSR Splnwriter $3088

55 CPS. Impact printer. Selectric print quality. Changeable print fonts. 110, 300 and 1200 baud data rate. Numeric keypad. Friction and tractor feed,

5510 Splnwriter $2754

55 CPS, Impact printer. Selectric print quality. Changeable print fonts. 110,300 and 1200 baud data rate. Friction and tractor feed.

& PRINTERS

DECLA120

Digital Equipment Corporation

DECLA120... $2388

180 CPS. Dot matrix. Upper/lower case. 1K buffer. Designed for 1200 baud communications. 30 character answerback message. Adjustable line spacing. Adjustable character sizes including double sized characters, Settable horizontal and vertical tabs. Top-of-form capability, RS232,

Perkin-Elmer Corporation

Pussycat 650/655 CRT Screen Printer

650/655 Pussycat CRT Screen Printer. $899

100 CPS, Extremely compact and quiet. 110 to 9600 baud rate. 2K buffer. Ideal for producing rapid, reliable hardcopy of your CRT screen display..Can beaddedto

any CRT with our interface option.

Digital Equipment Corp,

DECLA34DA... $939

30 CPS, Dot matrix. Upper/lower case. 4 character sizes. Up to 217 cols per line, 6 lines per inch settings. Friction feed. Settable tabs. RS232.

DEC LA34AA $1095

30 CPS. Dot matrix. Upper/lower case. 8 character sizes including double size characters. 6 lines per inch settings. Up to 217 cols per line. Friction feed. Settable horizontal and vertical tabs. Top-of-form capability. Options for LA34AA and LA34DA

Tractor Feed Mechanism $114

Numeric Keypad w/ Function Keys.. $69

Pedestal $100

Paper Out Sensor $25

APL Capability witti API Keycaps .. $499 2K Buffer witti Text Editor and 1200 Baud Communications Capability $499

Leasing rates and iease/purcticse plan information Is available on request. All equipment Is stilpped witti a 10 day money back guarantee. We offer full service, on site maintenance plans on ail equipment. Ail equipment in stock.

U.S. ROBOTICS

a03 N, WABASH SUITE 1713 CHICAGO, ILL BOBQI

SALES

GENERAL OFFICES SERVICE

t3l23 34B-5B5a [3121 346-5B5I C3I,

HOBBYWORLD

ELECTRONICS, INC.

19511 Business Center Drive, Dept B-5 Northridge, California, 91324

NAYSPE^^^

16K Memory $29.00

Add"Oll (Includes Shipping)

for TRS-80 ® Apple® and Exidy® Euerything you need to upgrade your system. Cat No. Description 1156 For tlie TRS-80 Keyboard Unit 1156A For TRS-80 Exp. Interface (prior to 4/1/79)

1156B For tlie TRS-80 Exp. Interface

(after 4/1/79) 1156C Apple II 115 6D Exidy Sorcerer

Verbatim Diskettes

$26.00/Box

(Includes Shipping)

• Datalife Formula

• Single Sided, Double Density

• 10 Diskettes per Box

Cat No. Description Use for

1147 Soft Sector TRS-80, Apple, ATARI

1148 10 Hole, Hard Sector North Star

1149 16 Hole, Hard Sector Micropolls

HOW TO ORDER

Order by phone or by mall. Pay by check, Visa, MasterCard, or C.O.D. (CCD. add $1.40 add'I.) Charge orders: Include Card No. and Expiration Date.

Toll Free (outside Calif): (800) 423-5387

Calif & Outside USA: (213) 886-9200

Watch for our new name, HW ELECTRONICS, appearing in our ads next month. We've changed our name because at HW, computers are more than Just a hobby.

310 May IWl © BYTE Publications Inc Circle 185 on inquiry card.

Listing 3 continued:

1350

FOR I

1 TO 5:

CALL - 32681!

net AX ±

1352

POKE

16293,0

1354

GOSUB

300

1356

POKE

16294,0

1358

FOR I

1 TO 50s

CALL

32667:

NEX!I*

1360

FOR I

1 TO 38s

CALL

32712:

T X

1362

CAliL

32646:

FOR I =

0

TO 10:

J

1364

FOR I

1 TO 26:

CALL

32681:

J

1366

CALL

32653

1368

FOR I

1 TO 50:

CALL

32681:

NEXT

I

1370

FOR I

1 TO 37:

CALL

32681:

NEXT

I

1372

CALL

32646:

FOR I =

0

TO 10:

NEXT

1

1373

REM Y AXIS

1374

FOR I

1 to 700

: CALL

■ 32712: NEXT I

1376

FOR I

1 to 13:

CALL

"

32667:

NEXT

I

1378

CALL

32646:

FOR 1 =

0

TO 10:

NEXT

I

1380

FOR I

1 TO 26:

CALL

32695: NEXT

1

1381

CALL

32653

1382

FOR I

1 TO 44:

CALL

32681:

NEXT

I

1384

FOR I

1 TO 43:

CALL

32667

NEXT

I

1386

POKE

16293,0

1388

GOSUB

400

1390

POKE

16294,0

1392

FOR I

1 TO 6:

CALL ■

- 32681:

NEXT I

1394

FOR I

1 TO 10:

CALL

32695

NEXT

I

1396

CALL

32646:

FOR I =

0

TO 10:

NEXT

I

1398

FOR I

1 TO 40:

CALL

32695:

NEXT

I

1400

CALL

32653

1402

FOR I

1 TO 50:

CALL

32681

NEXT

I

1404

FOR I

1 TO 33:

CALL

32667

NEXT

I

1406

CALL

32646:

FOR I =

0

TO 10

NEXT

I

1408

FOR I

1 TO 26:

CALL

32695

NEXT

I

1410

CALL

32653

1412

FOR I

1 TO 44:

CALL

32681s NEXT

I

1414

FOR I

1 TO 43:

CALL

32667: NEXT

I

1416

POKE

16293,0

1418

GOSUB

380

1420

POKE

16294,0

1422

FOR I

1 TO 6:

CALL

32681:

NEXT I

1424

FOR I

1 TO 10:

CALL

32695: NEXT

I

1426

CALL

32646:

FOR I =

0

TO 10: NEXT

I

1428

FOR I

1 TO 40s

CALL

32695: NEXT

I

CALL

32653

FOR I

1 TO 50:

CALL

32681

NEXT

I

1 X 1 y1 ±4 J 4

FOR I

1 TO 33:

CALL

32667

NEXT

I

1436

CALL

32646:

FOR I =

0

TO 10

NEXT

I

1438

FOR I

0 TO 26

CALL

32695

NEXT

I

1440

CALL

32653

1442

FDR I

1 TO 44:

CALL

32681

NEXT

I

1444

FOR I

1 TO 33:

CALL

32667

; NEXT

I

1446

POKE

15293,0

1448

GOSLIB

1450

POKE

15294,0

1452

FOR I

1 TO 6:

CALL

32681:

NEXT I

1454

FOR I

1 TO 10:

CALL

32695

NEXT

I

1456

CALL

32646:

FOR I =

0

TO 10

NEXT

I

1458

FOR I

1 TO 40:

CALL

32695

NEXT

I

1460

CALL

32653

1462

FOR I

1 TO 50:

CALL

32681

NEXT

I

1464

FOR I

1 to 33:

CALL

32667

: NEXT

I

1466

CALL

32646:

FOR I =

0

TO 10

. NEXT

I

1468

FOR I

1 TO 26s

CALL

32695: NEXT

I

1470

CALL

32653

1472

FOR I

1 TO 44:

CALL

32681

NEXT

I

1474

FOR I

1 TO 43:

CALL

32667

: NEXT

I

1476

POKE

16293,0

1478

GOSUB

340

1480

POKE

16294,0

1482

FOR I

1 TO 6:

CALL

32681:

NEXT

I

1484

FOR I

1 TO 10:

CALL

32695

NEXT

I

1486

CALL

32646:

FOR I =

0

TO 10: NEXT

I

1488

FOR I

1 TO 40:

CALL

32695

: NEXT

I

1490

CALL

32653

1492

FOR I

1 TO 50:

CALL

32681

• NEXT

I

Listing 3 continued on page 312

AU THESE FEATURES... THIS SMALL SMCE... AT THIS LOM PRKX!

Greater computer power. . . fewer separate components . . . larger capability . .. simpler to operate .... modular maintenance ...

These are the unique benefits of the Quasar Data QPD-100 Floppy Disk Computer. . . plus unsurpassed reliability...plus 12-month warranty on all PC boards.

Its highly reliable, industry-standard MFE drive is compact. Accepts both single AND double-sided disks.

Upgradeable from the Z-80® microprocessor-based system to our 16 BIT microprocessor-based system by simply plugging in extra PC cards. Hard disk and multi-user systems available.

As your requirements grow, your QDP-100 can grow to fit them.

The Quasar Data QDP-100H is a larger version with 6-megabyte capacity; includes one double-sided floppy and one SVi microwinchester hard disk.

Both the Quasar Data QDP-100 and QDP-100H are fully compatible with all standard terminals.

Phone or write for descriptive bulletin and specifications. And ask for a demonstration. Dealer inquiries invited.

QUASAR DATA'S QDP-KH) COMPUTER SYSTEM.

4,695

18" wide 16%" deep 11" high

Complete systems available

Z-80 is a trademark of Zilog Corp. CP/M and MP/M

are trademarKs of Digital Research Corp.

Circle 341 on inquiry card.

Quasar Data Products

10330 Brecksville Road, Brecksville (Cleveland), Ohio 44141

Phone: 216/526-0838 / 526-0839

Telex: 241596

SAVE!"

WITH DSC'S 10% CLUB

YOU CAN BUY HARDWARE, AT 10% ABOVE WHOLESALE

JOIN NOW: $15.00 ANNUAL MEMBERSHIP FEE INCLUDES $10.00 CREDIT TOWARD FIRST PURCHASE AND PRICE LIST OF PRODUCTS

TERMS - PREPAYMENT. CASH. CERTIFIED CHECK. M.O.iM.C. AND VISA ADD 4%: F.O.B. ORIGIN

MANUFACTURER'S WARRANY $100.00 MIN. PURCHASE

COMPUTERS

INTERTECSBe4K $2640.

0De4K ZENITH Ze9/4eK TRS-eOMODII64K TRS-80MODI1I16K

32K2DR. HP85

Apptett&n ' 16K

DRIVES — INC. P.S. a

2 DR. CABLE

8-CDCFOHMODII

MPI40TK1SIDE

80TK1SIDE

40TK2SIDE

80TK2SIDE L0B0/APPLE/C0NT3 ADDITIONAL DRIVE TANDON40K 1 SIDE

80TK 1 SIDE

40TK2SIDE

80TK2SIDE

2990. 2204. 3350. $854.

2100.

2782. 1141

ENC.

25. 749. 285. 379. 379. 499. 3495 434. 270365 365 455.

PRINTERS - "INC. TRACTORS

••NEC-5510

2530.

5530

2530

"C. ITOH —25CPS

1477.

••DIABLO630

2164.

1640RO

2509.

1650 RO

2656.

1650 KSR

2932.

CABLES Im.

35.

EPSON MX70

409.

MX80

485.

CENTRONICS 737-1

696.

TI810BASIC/SER

1480.

810 w/vcc g.

ASCII/SER

1943.

810 VFG & CP/

PARALLEL

1716.

820 KSR BASIC

1722.

825 RO LOADED/

75 OPS

1341.

PAPER TIGER 460G

1111.

ANADEX9500

1287.

9501

1287.

2KBUFFER/INST.

70.

OKIOATAMICROLINE

80

418.

62

617.

83

920.

TRACTORS

99.

TERMINALS — HAZELTINE

1410

715.

1420

787.

1500

837.

1510

1024.

1520

1202.

1552

1028.

ACCESSORIES

D-CAT MODEM

ISO.

LEXICON MODEM

129.

16KRAM-4116

29.

TRS-80EXP. INT.

246.

CALL FOR PRICES ON ITEMS NOT LISTED PRICES SUBJECT TO CHANGE WITHOUT NOTICE

I WANT TO JOIN NOW. NAME

STREET .. CITY

CHARGE D MASTER OHO. □ VISA CARD NUMBER

EXPIRATION DATE .

DISK SUPPLY CO.

SUITE 439. 111 S, OLIVE ST.. MEDIA, PA 19063^ (215) 461-5437

Listing 3 continued:

1494

FOR I

1 TO 33:

CALL

_

32667:

NEXT

I

149G

CALL

32646: FOR I =

0

TO 10:

NEXT

I

1498

FOR I

1 TO 26:

GALL

_

32695:

NEXT

I

1500

CALL

32653

1502

FOR I

1 TO 44:

CALL

32681:

NEXT

I

1504

FOR I

1 aO 43:

CALL

32667:

NEXT

I

1506

POKE

16293,0

1508

G05I1R

320

16294,0

1512

FOR I

1 TO 6:

CALL - 32681:

NEXT I

1514

FOR I

1 TO 10:

CALL

32695

NEXT

I

1516

CALL

32646:

FOR I =

0

TO 10

NEXT

I

1518

FOR 1

1 TO 40:

CALL

32695

NEXT

I

1520

CALL

32653

1522

FOR 1

1 TO 50:

CALL

32681: NEXT

I

1524

FOR 1

1 TO 33:

CALL

32667: NEXT

I

1526

CALL

32646:

PGR I =

0

TO 10: NEXT

I

1528

FOR I

1 TO 26:

CALL

32695: NEXT

I

1530

CALL

32653

1532

FOR I

1 TO 44:

CALL

32681

NEXT

I

1534

FOR I

1 TO 43:

CALL

32G67

NEXT

I

1536

POKE

16293,0

1538

GOSUB

300

1540

POKE

16294,0

1542

FOR I

1 TO 6:

CALL ■

- 32681:

NEXT I

1544

FOR I

1 TO 10:

CALL

32695

NEXT

I

1546

CALL

32646:

FOR I =

0

TO 10: NEXT

I

1548

FOR I

1 TO 40:

CALL

32695: NEXT

I

1550

CALL

32653

1552

FOR I

1 TO 50:

CALL

32681

NEXT

I

1554

FOR I

1 TO 33:

CALL

32667

NEXT

I

1556

CALL

32646:

FOR I =

0

TO 10

NEXT

I

1558

FOR I

1 TO 26:

CALL

32695

NEXT

I

1560

CALL

32653

1562

FOR I

1 TO 26:

CALL

32667

NEXT

I

1564

FOR 1

1 TO 100: CALL

- 32681: NEXT I

1566

CALL

32646:

FOR I =

0

TO 10: NEXT

I

1568

FOR I

1 TO 26:

CALL

32695

NEXT

I

1570

CALL

32653

1572

FOR I

1 TO 13:

CALL

32667

: NEXT

I

1574

FOR I

1 TO 50:

CALL

32712: NEXT

I

1999

RETURN

' 1' 1' i

Figure 3: Sample plot of results obtainable with the information included in this article.

May 1981 © BYTE Publidtiom Inc

Computer experts (the pros) usually have big computer experience. Ttiat's why when they shop system software for Z80 micros, they look for the big system features they're used to. And that's why they like Multi-User OASIS. You will too.

DATA INTEGRITY: FILE & AUTOMATIC RECORD LOCKING

The biggest challenge for any multi-user system is co-ordinating requests from several users to change the same record at the same time.

Without proper co-ordination, the confusion and problems of inaccurate or even destroyed data can be staggering.

Our File and Automatic Record Locking features solve these problems.

For example: normally all users can view a particular record at the same time. But, if that record is being updated by one user, automatic record locking will deny all other users access to the record until the up-date is completed. So records are always accurate, up-to-date and integrity is assured.

Pros demand file & automatic record locking. OASIS has it.

SYSTEM SECURITY: LOGON, PASSWORD & USER ACCOUNTING

Controlling who gets on your system and what they do once they' re on it is the essence of system security.

(THEN COMPARE J

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+ Y

-Y

VECTOR NOTATION

COMMAND

CHARACTER

HEXADECIMAL

ADDRESS

+ Y

P

8038

+X,+Y

q

8042

+ X

r

8049

+ x,-y

s

8050

-Y

t

8057

-X,-Y

u

B05E

-X

V

8065

-X, + Y

w

8060

PEN UP

y

8073

PEN DOWN

z

807A

Table 1: Chart of plotter pen-movement commands and the vector notation associated with each command.

Table 1 shows plotter commands and the vector notation associated

with each. Listing 2 on page 300 is a machine-language routine that generates the Specified command characters. To execute a given command, a jump is made to the appropriate hexadecimal address, where the proper character is loaded into the accumulator. A call is then made to the parallel-to-serial subroutine, where the command character is transferred from the computer to the plotter.

Results with the digital plotter have been encouraging. Figure 3 on page 312 shows an actual plot made on the plotter. A #0 Rapidograph pen was used to produce a high-quality plot. The plot is a simulation of the voltage drop across a capacitor that is placed in series with a resistor and a fixed voltage source. Figure 4 shows the flowchart of the program, and listing 3 begirming on page 302 shows the program with comments.

At present, the Apple II and Hiplot digital plotter are being used for several projects that include the spectral analysis of breath sounds, muscle voltages, and neural characteristics. The two units working together provide a low-cost, high-quality record of the analysis of scientific data.B

Text continued from page 298:

^ START ^

^ END J

1 PEN POSITIONED IN ~[_C0RNER J

DRAW AND LABEL X AXIS

DRAW AND LABEL Y AXIS

CALCULATE CAPACITOR VOLTAGE

PLOT VOLTAGE

Figure 4: Flowchart for the BASIC program used to produce figure 3.

314 May 1981 © BYTE Publications Inc

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BYTE May 1981 315

Recursion and Side Effects in Pascal

Robert Morris and James Perchik University of Massachusetts Boston Harbor Campus Boston MA 02125

Two features of Pascal, recursion and side effects, often cause difficulties for beginners to the language. Although these features appear to address separate issues, they are not uiu'elated, and for this reason confusion over one often accompanies confusion over the other. Conversely, contemplation of one can assist in an understanding of the other. It is easier to comprehend both issues if you look at the management of variables that results from procedure calls. That will be the focus of this article.

Typically, the concept of recursion is illustrated with simple functions that are better written without recursion. We will adhere to that custom for the standard reason of comprehensibility. Readers who master recursion will find an excellent treatment of the subject (when and when not to use it) in Nikolaus Wirth's Algorithms + Data Structures = Programs, listed in the references.

Consider the easy problem of computing the factorial n! = lX2X...Xn. Factorial is defined recursively as follows:

n! = n(n - 1)1 if n > 1 nl = 1 if n = 1

The following Pascal function computes the factorial function recursively:

FUNCTION fac(n: INTEGER): INTEGER; BEGIN

IFn = 1

THENfac := 1

ELSE fac : - fac(n - l)*n

END

Suppose that a main program contains the following calling sequence:

m := 3; y : = fac(m)

The function "fac" is recursive. That is, "fac(3)" will call "fac(2)", which will call "fac(l)". We say that there are three activations of this function, with parameter values of 3, 2, and, finally, 1.

Each activation of a recursive function (or procedure) must have a separate location (called the stack frame) for its local variables, parameters, etc. In this way, one activation (say, "fac(2)") does not disturb the contents of another activation (say, "fac(3)"). As each activation begins, a new stack frame is created (or pushed) for its local variables. As that activation is completed, its stack frame is destroyed (or popped), and control returns to the previous activation. The "current" values of the local variables are then taken from the stack frame of the previous activation, which is now at the bottom of the (downward-growing) stack. [In a stack, only the item most recently placed there can be accessed. We call this the top of the stack if the stack is growing "up." Since the stack in this context is growing "down," we will refer to the item that can he removed as the bottom of the stack....G\N]

Snapshots of the stack are shown in figure 1. The global variables "m" and "y" (ie: those declared in the main program) are allocated storage in the stack frame of the main program, which is shown at the top frame of the stack. These variables are not duplicated with each activation of the function. A function or procedure may be able to directly access and modify a global variable. That, as you will see, can lead to surprising results.

Above and between the snapshots of the stack in figure 1 is the fragment of code (plus comments, in braces) which caused the changes to the stack. This information helps specify the time when each snapshot was taken.

At any point in time, there are two currently active frames that are of immediate interest. These two frames contain the values that are currently accessible; they are the top and bottom frames in figure 1. The top frame contains the (global) variables of the main program. The local frames are shown below it, growing downward. The bottom frame is the only local frame that is currently accessible (ie: belongs to the current activation). In addition to local variables, the stack frame contains the value of the function (marked "P" if it is pending further calculations) and the return address (so that control will be transferred back to the correct calling sequence). The

316 May 1981 ® BYTE Publications Inc

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m: = 3

STORAGE FOR GLOBAL VARIABLES

STORAGE FOR LOCAL VARIABLES WITHIN "foe"

y: = foc(m) {=foc(3)}

STATEMENTS OF PROGRAM EXECUTING

toe: =

foo(n-l) foc(n-l) {lFn = lTHEN} fac(n-l)*n

{=fac(2)} {=fac(l)} fac: = l

m = 3 y = P

m=3 y = P

m = 3 y = P

m = 3 ycP

n°3

fQC= P

n = 3 fac=P

n =3 fac = P

n = 3 fac = P

n»2 fac'P

n = 2 fac = P

n = 2 foc = P

n = l foc-P

n = l fac = l

1

2

3

4

{=fac(l)*2}

fac: =

fac (n-1) *n {=fac(2)*3}

TIME

m = 3 y = P

n=3 fac = 6

y: = Fac(in) {= facia)}

Figure 1: ^ecution of the Pascal statements "m ;= 3; y ;= fac(m)". The columns of boxes represent the stack at time t=Q, 1, 2,...7. The statements above each column indicate the part of the function that is executed to give the stack illustrated below, and the comments in braces are used to clarify the statements being executed. The letter P indicates a pending calculation.

addresses have not been shown in figure 1.

Had the variables "m" or "y" occurred inside "fac" without a new declaration, these variables would be said to be global to the function, and then "fac" could access or change their values. When global variables are changed within a function, the function is said to cause side effects. Sometimes this is useful, but often it is dangerous, and should be used with caution.

When the program execution begins, the global frame is set up, and soon the variable "m" is assigned the value of 3 (see column 0 in figure 1). When the function call

"fac(m)" is reached, a stack frame for "fac" is set up (column 1) below the global frame, and the value, 3, of the argument "m" is assigned the parameter "n" and stored in the local stack frame. (This call by value is the default behavior in Pascal. The alternative method of passing values, variable parameters, will be discussed shortly.)

Now the value of "fac(n —l)=fac(2)" is required. In order to compute this, the function "fac" is called (recursively), this time with a parameter value of 2. A second local stack frame is set up with n=2 (column 2).

This activation will call "fac(l)", and its frame is set up

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318 May 1981 © BYTE Publications bic

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at the bottom of column 3. Since n=l, this can be evaluated without further recursion: the answer is 1, and is stored in the variable "fac" in column 4. Now the previous invocation of "fac" (with n=2) can complete its work. Its answer is 2Xfac(l)=2Xl=2, which is assigned to the variable "fac" in column 5 (where the stack frame of "fac(l)" has been popped).

The unwinding process continues as control returns to the previous call of "fac" (with n = 3), where the answer can now be computed as fac = 3Xfac(2)=3X2 = 6, and stored in coluirm 6. Finally, the answer is assigned to the global variable "y" in column 7.

Applications of Side Effects

Before we see how side effects can lead to unexpected trouble, we should point out that they can be used in

many legitimate ways. For example, no useful language can exist without the statement READ(x). It may also be useful to have a function that includes the following code:

IF denominator = 0

THEN write('attempt to divide by zero')

ELSE quotient: = nimierator/denominator

The procedures read and write both have side effects—they affect the status of the (global) files input and output.

Another useful application of side effects occurs when each activation of a procedure computes only part of the answer and places it into the appropriate section of a

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global buffer. When all activations of the procedure have done their jobs, this buffer will contain the entire answer, which can then be worked on. Examples are the recursive algorithms for sorting arrays and for backtracking (see Wirth, Chapter 3 and page 79, listed in the references). This mechanism is not without risk, however, because procedures other than the one intended can inadvertently modify the global variable.

Some languages provide the appropriate mechanism, eg: "own" variables in ALGOL-60 or static storage in PL/I and C. These variables have "local name scope" (ie: they can not be directly accessed from outside the procedure). However, they are allocated storage only once. Thus, like global variables, new copies are not made with each activation of the procedure, so their values are retained from one activation of the procedure to the next. The loss of this feature in Pascal is generally overshadowed by the pleasant fact that Pascal is a simplification of ALGOL-60, whereas PL/I is a "complification."

A Faulty "fac" Function

Now we'll look at a modification of the factorial program, where a variable parameter is used. Although it looks very much like the first version of "fac", you will see that it computes the wrong answer:

FUNCTION fac2 (VAR n:INTEGER):INTEGER; BEGIN

IFn = 1 THENfac2 := 1 ELSE BEGIN

n : = n - 1;

fac2 := fac2(n) * (n + 1)

END

END

Assume that it is called, as before, by the following sequence:

m : = 3; y : = fac2(m);

Note the keyword "VAR" in the function header. A variable parameter in Pascal does not copy the value of its argument onto the stack frame. Instead, a reference (ie: a pointer) to the argument (in this case, the variable "m") is placed on the stack frame. This method is known as "call by reference." There are times when you want to use this method—for example, when a large item like an array or file is a parameter, or when you want to change the value of a global variable. But disaster lurks, as we will indicate shortly.

The argument in a call by reference must also be a variable (see Wirth, page 71). This prohibits a call like 'fac2(n—1)", since (n—1) is an expression, not a variable. Therefore, the variable "n" must be decremented in the ELSE clause. This appears to make the same mathematical calculation as in the previous version of the function "fac" because the multiplication is now by (n-f-1), the original value of n. In fact, it does not.

By having a variable parameter, "fac2" is able to get into the global variable "m" and (if you are not careful) change its value.

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BYTE May 1981 321

STATEMENTS OF PROGRAM EXECUTING

* -->

1-4

c +

" 5

n "

STORAGE FOR GLOBAL VARIABLES

m = 3

STORAGE FOR LOCAL VARIABLES WITHIN "fac2"

m=3« y = P

fac2 = P

m = 2

y = P

fQC2=P

m = 2-. y = P

fac2=P

foc2 = P

m = l y = P

fac2 = P

fac2»p

m = l • y=P

fnc2 =P

fac2»P

foc2=P

m = l . y = P

fac2=P

n= — fao2 = P

fac2 = l

m = l . y = P

fac2=P

fac2=2

m=l. y = P

fac2=4

y»4

TIME

Figure 7: Execution of the Pascal statements "m : = 3; y : — fac2(m)". In this case, the variable "n" within the function "fac2" {listed in the text) points to the global variable "m" and can change its value; the arrows from "n" to "m" indicate this relationship.

Consider the stack diagrams for the function "fac2" (see figure 2). This time, each new instance of "n" gets a pointer to the variable "m" and the code "n := n—1" causes the global variable, "m", to be decremented by 1. Still, no values can be assigned to "fac2" until the stack starts to unwind, and when that happens, the value of "m" has been decreased to 1. Thus the multiplication is always by 2.

As you see, this function is not computing factorials at all, but 2"'"'. The problem arises because "fac2" is altering the value of its parameter, a situation to be avoided when not absolutely necessary. After the entire function terminates, the variable "m" will be left at 1, regardless of its initial value. The function "fac2" is exerting a side effect on "m".

Side effects can occur whenever a procedure accesses a global variable either directly or indirectly via a variable parameter. Side effects are avoided by the use of local parameters (declared within the procedure or function) and value parameters. Many side-effect errors are so easy to make and so hard to debug that language designers will prohibit certain ^angerous constructs (or encourage the implementors to do so). (See Pascal User Manual and Report, page 79, listed in the references.) For example, the use of global variables (or parameters) for the control of "for" loops is prohibited by the CDC implementation of Pascal described in The Pascal User Manual and Report (pages 120 and 121, and error messages 155 and 180).

One of the most discomforting difficulties in debugging

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Programmers should strive to write

code that Is clear, correct, verifiable, and easily transported to other Implementations.

functions with side effects may occur if f Xg is not equal to g X f, at least if "f" or "g" is a function. Consider, for example, the apparently simple modification of the "fac2" function that is made by changing the key line to:

fac2 := (n + l)*fac2(n)

The reader is invited to make a stack history as above. Assume that multiplications are performed left to right, and that the stack frame for "fac2" also allocates a location to hold the value of the expression (n + 1) until after "fac2(n)" is computed, with the two values then being multiphed. (In practice, values of such expressions may be stored as temporary variables in registers.)

As a result of this single change, "fac2" will compute the correct value of factorial. What is the moral? Whenever the spectre of unplanned side effects rears its ugly head, discovery of the "correct" solution may be a matter of luck (and might depend on the implementation!). In any case, programs are certainly hard to debug whenever f Xg and gXf are not equal.

There are, of course, simpler examples that illustrate this phenomenon. Consider the following function:

FUNCTION f(VAR i:INTEGER):INTEGER; BEGINf := i;i:= i-H lEND;

This function simply returns the value of its argument, but has the side effect of incrementing that argument. The following sequence:

X : = 1; WRITE ( (x + l)*f(x) ); x: = 1; WRITE ( f(x) * (x + 1));

produces a printout of:

2 3

In this case, the printout (which would have been "2 2" \i the order of multiplication had not mattered) vindicates our assumption that multiphcation was performed left to

right.

The order in which multiplications are performed is (deliberately) left unspecified by the semantics of most programming languages. For example:

X := 1; WRITE(x*f(x)); x:= l;WRITE(f(x)*x);

produces a printout of:

2 2

and we must conclude that the value of the expression f(x) is evaluated before the value of the variable "x". This may be done for optimization reasons, in order to minimize register use. Furthermore, an optimizing compiler may choose not to evaluate f (x) at all in an expression like 0*f(x), since the answer is always zero. In that case, any side effects of the function "f" on "x" would not appear.

In short, the results of these examples can very well depend on the implementation! It is bad practice to write this kind of code, and programmers should strive to write code that is clear, correct, verifiable, and easily transported to other implementations. If you can avoid unnecessary side effects, you will be one step closer to this goal. B

References

1. Jensen, K and N Wirth. Pascal User Manual and Report. SpringerVerlag, 1974.

2. Wirth, N. Algorithms + Data Structures = Programs. Englewood Cliffs NJ: Prentice -Hall, 1976.

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324 May 1981 © BYTE Publications Inc

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BYTE May 1981 325

DEMONS:

A Symbolic Debugging Monitor

A I Halsema 4921 Patrae St Los Angeles CA 90066

This symbolic debugging monitor for the 6800 processor, DEMONS, can make debugging of machine-language programs devilishly easy by allowing you to control the sequence of program execution and the contents of registers dynamically. Requiring only $40 worth of easily built hardware and 1500 bytes of memory, DEMONS provides the 6800 with a virtual programmer's console able to display instructions in mnemonic form.

Monitor Features

DEMONS includes a flexible

disassembler that can be used by itself, with your programs, or with DEMONS. All variables are stored in the MIKBUG scratchpad memory (hexadecimal locations AOOO thru A07F), making DEMONS a candidate for being stored in read-only memory. Single-step and trace functions are implemented with a peripheral interface adapter (PIA) and two readily available integrated cir

About the Author

AiUil Ian Halsema has worked as a programmer since 1971. He is now a senior member of the programming staff at Xerox Corporation. He owns a Southwest Technical Products Corporation 6800 system equipped with 16 K bytes of memory, a CT-1024 video terminal, an AC-30 cassette tape interface, and an Okidata CP-no printer.

cuits, which together form a hardware cycle counter producing nonmaskable interrupts. This cycle counter technique is the same as that used in Motorola's EXORciser development system, and allows stepping through programs in read-only memory.

Debug machinelanguage programs for 6800 systems using instruction mnemonics.

The disassembler requires less than 1 K bytes of read-only memory, produces symbolic program listings similar to those produced by an assembler, and can be used to produce source code for input to an assembler (for instance, if you need to reassemble a program to incorporate modifications). As an added feature, the disassembler calculates and displays the effective address referenced by relative address mode instructions.

Disassembler Routines

The disassembler subsystem consists of three main routines: operator interface, disassembler, and an out

put routine for terminal display of disassembled code. The user can write his own interface and other routines for special applications. Any operator interface routine must set the first (or only) address of code to be disassembled, the number of lines of disassembled code to be produced (128 lines maximum), and the address of an output routine.

The operator interface routine calls the disassembler as a subroutine. Control will not be returned to the operator interface until the disassembler has produced the required number of lines of code. As each line of code is completed, the disassembler calls the output routine. When the disassembler is done, it returns control to the operator interface routine with the line count set to 0 and the address of the input code incremented to point to the next instruction.

The built-in operator interface is designed for use with video terminals having displays in a format of sixteen lines of thirty-two characters each, although it will work with other types of terminals. Since each line of output is thirty-two characters in length, the interface routine will cause a single page of fifteen lines to be displayed, with the cursor at the bottom of the display (as illustrated in figure 1). A new address can then be entered. If

326 May 1981 © BYTE PubUcalions Inc

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BYTE May 1981

327

you wish to view the next sequential set of fifteen lines, type a nonhexadecimal character followed by a G. The disassembler executes quickly; it will be input/output (I/O) bound (having to wait for I/O operations to finish) up to terminal data rates of about 3000 bps.

Disassembler Tables

Almost half of the memory space taken up by the disassembler is used for two tables. The larger of the two is the packed-mnemonic table. Each entry in this table is 2 bytes long, with entries arranged in ascending operation code order. Those operation codes which are undefined (such as hexadecimal 00) are represented in the table by the FCB pseudo-operation mnemonic. Each entry is formed by dropping the fourth character of the mnemonic (either an A or a B as in LDAA), masking out the 3 high-order bits of each of the remaining characters, and packing them into 16 bits. The high-order bit of the 16 is used as a flag to specify an alternate entry in the smaller table. Note that this method of packing characters is valid only for character codes with the same high-order 3 bits. Numeric and alphabetic ASCII characters cannot be packed together. Figure 2 gives an example of mnemonic packing.

The smaller table is the format table. It defines the address mode, the fourth character of the mnemonic symbol, and the number of bytes in the input object code. The format table consists of thirty-two 1-byte entries with two entries for each possible value of the high-order nybble (ie: half-byte) of the input op code. The second entry of a pair is selected when bit 16 is set to the value 1 in the corresponding packedmnemonic-table entry.

This method of defining formats and mnemonics works for all but three mnemonic symbols. The PSHB, PULB, and BSR op codes are exceptions that must be handled differently in the program. A fourth exception is the FCB pseudo-operation which has its own format-flags byte outside of the table.

During execution of the disassembler, the op code is used as an index into the packed-mnemonic table, while the high-order nybble of the op code is multiplied by 2 and is used as an index into the format

123*5678 9 01234567890123456789012

1

2 3

-A

0

0

0

0

3

7

P

S

H

B

-4

0

0

0

1

1

6

T

A

B

0

0

0

2

4

4

L

S

R

A

4

0

0

0

3

8

D

0

4

B

S

R

$

0

4

0

0

0

9

5

0

0

0

5

1

7

T

B

A

6

0

0

0

6

8

4

0

F

A

N

D

A

#

0

F

7

0

0

0

8

3

3

P

U

L

B

8

0

0

0

9

8

B

3

0

A

D

D

A

#

$

3

0

9

0

0

0

B

8

1

3

9

C

M

P

A

#

?

3

9

10

0

0

0

D

2

3

0

2

B

L

S

$

0

2

$

0

0

1

1

11

0

0

0

F

8

B

0

7

A

D

D

A

#

0

7

12

0

0

1

1

A

7

0

0

S

T

A

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$

0

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13

0

0

1

3

0

8

1

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14 15

16

0

0

1

4

3

g

R

T

s

0

0

1

5

0

0

F

C

B

$

0

0

V

i

Figure 1: Example of disassembled code as it appears when output to a video terminal screen.

Mnemonic to be packed: LDX

ASCII Hexadecimal Representation: 4C 44 58 (0100 1100 0100 0100 0101 1000)

■ . ' ' . '' . '

LDX

Deleting the high-order 3 bits: 0 1100 0 0100 1 1000

LDX Collecting the bits in 2 bytes: 00110000 10011000 (30 98)

not used ^ L D X

Figure 2: Forming an entry in the packed-mnemonic table. The three high-order bits are stripped from the ASCII representation of each character of the three-letter mnemonic. The 5-bit characters are packed into two 8-bit bytes, with one bit not used. The characters are restored to 8-bit form by adding hexadecimal 40 to the 5-bit value.

table. The packed mnemonic is unpacked, and the 3 high-order bits of each character are restored by adding hexadecimal 40 to each 5-bit value. The unpacked ASCII characters are stored in a line buffer along with the fourth character, if any, of the mnemonic.

The operand field is built using format table data indicating the length and address mode of the instruction. If an immediate-mode instruction is being processed, the operand is preceded by a "§" character. If the instruction uses relative addressing, the absolute effective address is calculated and is placed in the comments field of the output buffer. If the instruction uses indexing, the operand is followed by a ",X" sequence. All operands are in hexadecimal. All fields in the line start at fixed locations, making for easier user processing.

Hardware Additions

The hardware cycle counter is connected to side A of the peripheral interface adapter. Figure 3 shows a schematic diagram of this. In my system, a Southwest Technical Products Corp (SwTPC) 6800, the peripheral interface adapter is on an MP-L parallel interface board which is connected to the system reset line. On power-up or reset conditions, data direction register A (DDRA) and I/O register A (lORA) cause logic 1 levels to appear on the MP-L's output lines. If applied directly to the counter, these levels would start the counter running and producing interrupts before the system could properly process them.

To avoid this condition, a 7404 hex inverter is used to complement the load, clear, and enable signals, and to keep the counter halted and cleared following power-up and system reset.

328 May 1981 © BYTE Publications Inc

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BYTE May 1981 329

NMI <□ «

38

CLOCK ^2 O

GND

CAl

PAl

PAD

IRQA

PA4

PA 5

PAS

PAT

ICl

MC6821

PIA

ICl 7404

4>

: o.oi;iF

T CARRY

CLEAR

LOAD

Pi

ENABLES

*1

B

'INPUTS

C

:C2

D

>

74161

CLOCK

-0 + 5V SUPPLY -[3> GROUND

PIA I/O REGISTER A

7

6

5

4

3

2

1

0

COUNT BIT 3

COUNT BIT 2

COUNT BIT 1

COUNT BIT 0

X

CLEAR

LOAD

ENABLE

Figure 3: Schematic diagram of the hardware cycle counter. The DEMONS system uses the nonmaskable interrupt (NMI) in

the 6800.

Number Type +5V GND

ICl 7404 14 7

IC2 74161 16 8

From the program's viewpoint, the counter clear is off when lORA bit 2 is a 1, counter load is off when lORA bit 1 is a 1, and counter enable is on when lORA bit 0 is 0. lORA bits 4, 5, 6, and 7 are used to output the value to be loaded into the counter, leaving lORA bit 3 unused.

The 74161 device in figure 3 is a 32 MHz synchronous 4-bit counter whose carry output will go high for a period equal to one full machine cycle when a count of 15 is reached. By presetting the counter, the carry output can be made to go high after 1 to 15 clock cycles.

I built the prototype version of the cycle counter on a perforated circuit board and attached it to the MP-L board, which supplies power and clock signals. You can see this mounting technique in photos 1 and 2. This assembly plugs into the motherboard and I/O board slot 3, giving it the hexadecimal address range 800C through 800F. If the cycle counter is to be plugged into some other slot, DEMONS will have to have the new address of lORA patched in at hexadecimal locations 03E9, 03EA, 040B, and 040C. DEMONS uses the nonmaskable interrupt (NMI), so the interrupt-request acknowledge (IRQA) line must be wired to the NMI input on the cycle counter's peripheral interface adapter board.

How the Cycle Counter Works

Upon start-up DEMONS initializes the peripheral interface adapter and loads an initial value of 6 (count 9 phase-2 clock cycles) into the counter. The counter is started and a return from interrupt (RTI) instruction is executed. The counter will reach the terminal count value and toggle the CAl line one cycle before the RTI instruction completes execution. Upon completion of the RTI instruction, the processor will recognize the interrupt, save the registers in the stack, and transfer control to the DEMONS interrupt routine via the previously set NMI vector address.

DEMONS' interrupt processor will test the cycle counter's peripheral interface adapter control register A to verify that it was entered as a result of a valid interrupt. If the cycle counter did not cause the interrupt, the instruction at hexadecimal location

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330 May 1981 © BYTE Publications Inc Circle 320 OH inquiry Card.

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circle 40 on Inquiry card.

Photo 1: The cycle-counter circuit was constructed on a small piece of perforated board and mounted on the MP-L parallel interface board inside the SwTPC 6800.

Photo 2: Shown here is the 'method of mounting the cycle-counter circuit board.

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0411 will be executed. DEMONS is supplied with three no-operation instructions (NOPs) starting at this address. You should patch DEMONS to jump to another nonmaskable interrupt processing routine if the cycle counter is not the only source of nonmaskable interrupts.

If the interrupt is valid, the counter is halted, cleared, and reloaded with a value of 3. The registers are fetched from the stack and displayed on the terminal along with the next instruction to be executed, in this case the first instruction of the problem program. DEMONS then waits for the user to enter a command. If the step command is entered, the counter is started and a return from interrupt

(RTl) instruction is executed. Twelve phase-2 (<t>2) clock cycles later, the CAl line is toggled, producing another nonmaskable interrupt. Since the RTl instruction takes 10 cycles to execute, the interrupt occurs during execution of the first instruction of the program that is being debugged. From this point on, interrupts will occur after the execution of the RTl instruction as each instruction of the program being debugged is executed.

Operational Modes

In step mode, DEMONS causes a single instruction of the program

being debugged to be executed, and then seizes control of operations to

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Command Description

S. Step and execute from current address.

Snnnn Set hexadecimal address nnnn as the new current address.

Jnnnn. Set trace mode and breal< address nnnn. Break count set to 1.

Tnnnn.l 1 Set trace mode and break address nnnn. Set break count to 11.

Cnn Set condition codes to hexadecimal value nn.

Bnn Set B register to hexadecimal value nn.

Ann Set A register to hexadecimal value nn.

Xnnnn Set X register to hexadecimal value nnnn.

R Display registers.

D, Display 14 instructions in disassembled form slarting at the current

address.

Dnnnn Display 14 instructions in disassembled form starting at hexadecimal

address nnnn.

G Exit from DEMONS and resume problem program execution at the

current address.

Pnnnn,oo oo ... Patch memory starting at address nnnn with the hexadecimal values 00. Terminate entry with a carriage return.

Table 1: Sumnin'-i- ^ description of the DEMONS command set.

Dialogue at Terminal

Comments

*L

Command MIKBUG to load DEMONS from tape.

*G

Start DEMONS execution.

P 1E00

Tell DEMONS where to Start problem program

being debugged.

CC B A X

DEMONS displays registers.

El 00 00 3745

1E00BD1E45 JSR$1E45

DEMONS displays the next instruction.

: S.

Operator commands an instruction step.

CCBAX

DEMONS displays registers.

El 00 00 3745

1E45 37 PSHB

DEMONS displays the next instruction.

:T1E5F,03

Enter trace mode.

: S.

Start tracing.

Tabk 2: Example of a typical user work session with DEMONS, with commentary.

Characters in italics have been typed by the user.

Simultaneous Interrupts Processor Action

f NMI and SWI Early (PK) Mask < NMI and IRQ

LiRQ and SWI

(reafs as IRQ handles NMI first handles SWI first

f NMI and SWI handles NMI first

Later Masks < NMI and IRQ handles NMI first

L IRQ and SWI handles IRQ first

Table 3: Sequence of interrupt linndling in the Motoroln 6S00 microprocessor. Parts produced during early production runs used tlie PK chip mask, and deinojistrate unexpected behavior under certain interrupt conditions, niost iiotahly the simultaneous occurrence of a nonmaskable hardware interrupt (NMI) and a software interrupt (SWI). The PK series of 6800 branches to the IRQ (maskable hardware interrupt) vector location whenever this happens. (Parts of the PK series have the letters PK inscribed somewhere on the surface of the paika,fc: therefore tliey may be identified.) Later production rinis of the 6S00 processor used an improveil chip mask, and devices from these later runs handle interrupts in a more logical manner.

Tlie following rule liolds true for all 6800 processors: in the case where the IRQ signal is overruled by one of the other two interrupts, tlie IRQ may be ignored and lost mdess its interrupt signal has been latched. Fortunately, the IRQ, signal from the peripheral interface adapter (PIA) is latched.

allow user input. At this point, the

user can modify the program; aJter the path taken through the program; change the contents of the condition code registers, index register, or either accumulator; display memory content in disassembled form; or enter the trace mode.

In trace mode, DEMONS continues to receive control following execution of problem program instructions, but the user is not given control (that is, a chance to input commands) until the break address (or breakpoint) is encountered and the break counter is decremented to 0. The user sets the break address and the break count. Once set, these cannot be cleared without going through DEMONS initialization or executing the program being debugged until the break address is encountered N times. The break address entered must always be the address of the op code (ie: first byte) of an instruction byte sequence. Once trace mode is selected, tracing will be started by entry of the step command. Using the trace feature, the user can avoid stepping through long loops and previously debugged code one instruction at a time. Table 1 shows the complete command set of DEMONS; table 2 shows an example of user interaction.

DEMONS may be exited by use of the GO function, which bypasses the counter start-up code, or by activating the system reset line (by hitting the reset switch).

Possible Problems

All debugging monitors have

drawbacks; DEMONS is no exception. Since DEMONS relies on having the stack-pointer (SP) register properly set, code which uses the stack pointer as an index register must be bypassed using the step function. Any code that is synchronized with some external process or has critical timing requirements will be delayed by at least 130 machine cycles per instruction, causing possible errors. If a software interrupt (SWI) or regular maskable hardware interrupt (IRQ) occurs simultaneously with the cycle counter's nonmaskable interrupt (NMI), possible vectoring problems may occur. (Table 3 summarizes these effects.) Thus care must be

334 May 1981 © BYTE Publicatioiu Inc

Circle 230 on Inquiry card.

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/ stated thai the disassembler executes quickly, and will have to wait for inpui^i^M (I/O) operations when using terminals having data rates of up to about 3000 bits per second (bps), I calculated this figure by disassembling 128 instructions and noting the time required to complete this task (Tl). The time required for I/O operations (T2) was determined from the following formula:

T2 = (C X L) X D

where:

C is the number of characters per line (32) L is the number of tines in the test (128)

D is the time required to transmit one character (0.033 seconds at 300 bps) The processor time required to disassemble the 128 instructions is then: T, Tl - T2.

The disassembler is no longer I/O bound in speed of execution when Tp = T2 for the 128-line test. The system is I/O bound when T, < T2, and is compute bound when T, > T2.

taken when using DEMONS to avoid stepping through software interrupt (SWI) instructions. Likewise, I/O operations involving a regular maskable interrupt (IRQ) may not work correctly every time.

Other Considerations

Several extensions to DEMONS are possible. The patch function is not symbolic, but may be made so by using the disassembler tables in reverse and using a subset of the 6800 assembly language restricted to hexadecimal operands. This feature was not included in this version of DEMONS because of the need to avoid using excessive amounts of programmable memory. Another extension could be to allow the entry of

multiple addresses for the trace function to compare against. This feature would be useful if a situation arose in which the program under test could take several possible and unpredictable paths.

To use the disassembler in standalone mode, control should be passed to hexadecimal location GOOD. The disassembler will reply by outputting a blank character to the terminal. Enter the four-digit hexadecimal address of the area of memory whose contents are to be displayed. The disassembler will issue home-up and erase-to-end-of-frame cursor commands to the terminal and will begin displaying lines of disassembled code. When 15 instructions have been displayed, the disassembler will pause

awaiting entry of the address of the next area of memory to be displayed. If a nonhexadecimal character is entered, MIKBUG will resume control.

DEMONS is started by transferring control to hexadecimal address 03CC. DEMONS will output the character P to the terminal and await entry of the four-digit hexadecimal address of the program to be debugged. Following entry of this address, the contents of the registers and the next instruction to be executed from the program being debugged will be displayed. DEMONS then issues a colon (:) as a prompt character and awaits entry of a command at the control terminal. If a format error is made while entering a command, DEMONS will output a question mark and again prompt for input.

The most efficient way to use DEMONS is to step through undebugged code a single instruction at a time, patching errors as they are encountered and correcting the contents of the registers when necessary, in an attempt to find as many bugs as possible in a single run. When the number of patches becomes unwieldy, or an unpatchable bug is found, or the last bug is found, only then should you reload the assembler and reassemble the problem program. This technique will reduce the number of times you have to load memory from your mass-storage device and so will increase productivity. ■

Listing 1: The main debugging routine of DEMONS, assembled in code for the 6800 microprocessor. This program uses the cycle counter, shown in figure 3, to generate interrupts that allow it to take command from the user program.

00100

NAM

DEMON

00200

•

00300

• AUTHURl A.I, HALSEMA

00400

♦ DATEl

ll/UB/77

00500

• OBJECT

MACHINEI SWTPC 6800

00600

• PROGRAM NAMEI

DE'^ONCS) VERSION 1,0

00700

• DEBUG

MONITOR

(SlfMBOLIC) INITIALIZATION

00800

•

00900

*

THIS

ROUTINE READIES THE PIA

AND STARTS THE HARDWARE CYCLE

01000

•

COUNTER. IT WILIj REQUEST THE

STARTING ADDRESS OF THE CODE

01100

»

TO PE

DEBUGGED t<ITH A PROMPT, IT ALSO REMOVES TRACE

01200

SETTINGS,

01300

OPT

0

01400

03CC

ORG

t03CC

01500

*

01600

A075

XSAV

EQU

tA075

X-REGISTEB SAVE AREA

01700

A02F

STAK

EOU

$A02F

DEfONCS) STACK AODRESS

01800

A006

NM IV

EOU

SA006

^MI INTERRUPT VECTOR AODRESS

01900

ElDl

OI.ITEEE

EOU

SEIDI

OUTPUT CHARACTER ROUTINE

02000

A07S

TP-LAG

EQU

sA07ei

TRACK ACTIVE FLAG, 1= ACTIVE

02100

AOOC

ADDR

EQU

SAOOC

ADDRESS STOBAGF- USED BY BAIiDR

O220U

80UC

HCCPIA

EQU

»900C

CYCLE COUNTER PIA ADUHESS

02300

A07C

APPND

EOU

(A07C

APPENDAGE ADDKESS FtJH DISASM

02400

A077

LINES

EUU

$A077

LINES FOP DISASM Tt) DISPLAY

02SU0

01A4

APP

ICOU

$UlA4

APPENDAGE ADDRESS IN DISASM

02600

KOCA

□ IIT2HS

EQU

8E0CA

OUTPUT 2 HEX DIGITS AND SPACE

Listing 1 continued on page 338

336 May 1981 © BYTE Publications Ire

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BYTE May 1981 337

Listing 1 continued:

02700

Eoce

0U'r4HS

EjU

SE0C8

OUTPUT 4 HEX UIGITS AND SPACE

02800

A079

TADDR

tou

$A079

TRACE KECUGNITION ADDRESS

02900

ElAC

INEEE

EOU

SEIAC

CHARACTER INPUT ROUTINE

03000

E07E

PnATAl

EilU

seo7E

PRINT BLOCK ROUTINE

03100

001 8

NEXTL

EOU

$0018

DISASSEMBLER ENTRY PUINT

03200

»

03300

« DEHOVCS)

STA!<T

-UP ENTRY POINT

03400

03500

0 3CC

H V.

A02F

START

LOS

jlSXAK

SET STACK ADDRESS

03600

03CF

7F

A078

CLR

TFLAG

RESET TRACE FLAG

03700

03D2

BU

047D

UG

JSR

CURL

ISSUE CK/LF

03800

0305

8 b

s 0

LOAA

< > P

03900

0 3U7

BO

E 1 D I

JSR

ClUTEEE

ISSUE PROMPT

O4OUO

03da

BD

04B2

JSP

BAU UR

GET START OF PROBLEM PROGRAM

04100

030D

25

F3

BCS

UG

BAD INPUT- TRY AGAIN

04200

03L>F

BD

0561

JSR

StTAl)

O43OO

03^2

CK

O4OA

LuX

» I N T P

SET UP t,if\ VECTOR

04400

OJKS

ff

A006

STX

N M1 V

04500

0 36 8

C K

0 yC

LDX

• rtCCPI A

INITIALIZE PIA/CYCL.E COUNTER

046U0

03EB

bF

U 1

CLR

11 X

SELECT DDPA

04700

03ED

t) 6

FF

LUAA

tf $FF

AND SET UP ALL LINES TO OUTPUTS

U4EiOC

03tF

A7

00

STAA

X

04900

0 3F1

66

04

I.DAA

• $04

SELECT lOPA

05000

0 JK3

A 7

0 1

STAA

1,X

05100

l)3Fl5

bB

liDAA

«S6<)

TURN OFF COUNTER BESET

0520U

03f7

A7

0 0

STAA

X

AND SET INITIAL COUNltK VALUE

05307

03F9

A6

00

SETUP

bDAA

X

05400

03FR

64

F9

AnDA

• SF9

TURN OFF COUNTER LOAD

05500

()3F"U

A /

U 0

STAA

X

OSbO'.l

03FT

U 7

LDAA

«S07

ENABLE CAt INTERRUPT ON LUx lU

057'10

Olu 1

A 7

0 1

STAA

l.X

,hir,H TPAf.SlTIUnS

05 So.)

040 3

Ab

00

LjOAA

X

OSiOO

0405

R4

KH

A-MDA

»SFe

START CUUMEH

06000

04 U 7

A7

00

STAA

X

06100

0409

3B

PTI

GO TO PRDBLEM PRHGRAM.

06 200

#

06300

l''TF«

M

AKij OPERAIt'R cii'-i^ANr i)trnnl>'Gi

06400

*

tNTtRED (JMl. 1 UPi.'N

IICCDRENCE

UF NMI INTERRUPT,

06500

*

LIJCATIOM LAhELIiFU

■USER" ALLOWS FOR PATCHING IN JU«PS

066U0

«

TU FURTHER l«TE»RtJPT

PROCESSING IF MOPE THA'I ONE SOURCE

06700

Ut ■■■iM INTERMUPTS

IS

AVAILABLI- .

06 800

06900

04UA

CE

Bl.'0C

IMRP

I.DX

•rtCCPIA

GFT PIA ADDRESS

07000

040D

60

0 1

TST

.AND CHECK FOR CYCLE CUUnTER

07100

040F

2h

0 3

HIT

HINK

.IMERRUPT

07200

0411

01

US&R

NOP

PATCH A JUhP TU SOME OTHER NMl

07 30U

0412

01

NOP

.PROCESS HERE, BECAUSE THIS

07400

0413

0 t

wflP

.INTERRUPT IS NOT FROM CYCLES.

07500

0414

H b

u 4

HINE

LUAA

»SU4

niSABLE COUNTER INTERRUPTS

07600

041b

A 7

0 1

STAA

1,X

07 700

0418

66

3F

LDAA

• $3F

STOP COUNTER

07 800

041A

A7

uO

STAA

X

07900

041C

a b

3B

LtlAA

llS3hi

RESKT CClUMtR. SET LOAD VALUE

oeoou

U4 1 E

A 7

0 0

SI A A

X

, TD 3

US loo

0420

A b

00

liUAA

X

DUMMY READ TO U.SUKE N I OFF

08 200

0422

30

TSX

08 300

0423

KK

05

LUX

5,X

GET ADDRESS OF NEXT INSTPUClJoN

08400

0425

rv

A 0 OC

STX

ADUR

SET ADDRESS FOR DISASSEkiBLER

08500

042 d

7 D

A 07 H

TSI

TFLAG

TRACE "ODE PUNNING?

08600

042B

2 7

OA

HEU

NOT

IF t«ni. BRANCH

08700

0420

BC

0 7 Q

CPX

TADDR

IRACt FLAC; SFT- fFST AUORESS

08800

0430

2 6

5 2

bNE

MiPt

BRANCH If HHn:>i(; ADDRESS

089UO

0432

7A

A 07 8

IJEC

TFbAG

ADDRESSES ARE EQUAL- COUNT HIT

09000

0435

* 0

B^lE

NOPE

IF NOT ZERO- (;ri TRACE SOME MORE

091UIJ

0437

9 h

fi 1

wUT

LDAA

• 901

SET NUMBER IIF LINES FOR LlISAS'i

09 200

0 439

B 7

A 0 7 7

STAA

LINES

09 3U0

0 43C

H 0

* (1

HSR

RECiS

t'O A CR I-F AND DISPLAl REGISTERS

09400

043E

BD

056 F

JSR

SHOLIN

DISPLAY INSTRUCTION

09S00

0441

6 6

3A

LDAA

•

GET CIIKNAND- ISSUE PROMPT

09600

0 443

BiJ

E1 D I

JSR

OUTEEE

09 7 00

0 44b

Bl)

ElAC

JSR

INEEE

GET ItPH

09 800

0449

CE

0578

IjDX

•COMTaH

GFT COMMAND TABLE ADDRESS

U9900

0 44C

Eb

00

TEST

LDAB

X

GET RfcCOGMTIIlH CHARACTER

10000

044E

1 1

CSA

8A^E AS INPUT?

10100

0 4 4F

« b

04

BNE

illiRE

IF NOT- GU LOOK AGAIN

10200

0451

K. E

0 1

LOX

1 . *

EQUAL- l".Et CUMRENT address

10300

0453

bK

0 0

J»tP

X

GO DO IT TO IT

10400

*

10500

0455

50

MORE

TSTP

FOUND END OF TABLE?

lObOO

0456

27

05

HEO

BAH

YES- TELL OPERATOR

10700

0458

08

I NX

No- POINT TO NEXT ENTRY IN TAaLE

loeoo

0459

OB

I«X

10900

045A

08

IIX

liouo

0458

2 0

EF

BRA

TEST

AND Gtl TEST IT

11100

• INPUT IS

BAD

TELL OPERATOR

ANi. GIVE

HIM ANOTHER CHANCE TO DO It RIGHT

11200

U45D

Mb

3F

BAD

I.DAA

»'7

DISPLAY OUESTlON MARK

11 300

045F

BD

ElDl

JSR

OUTtEF

ll40n

04b2

PD

1 I)

NEXT!

bSR

CUHL

DO CARRlAGt »tTURN/LXNE FEED

U500

0464

20

DB

BRA

CUMCJN

AND GO TRY AGAIN

Listing 1 continued on page 340

338 May 1981 © BYTE PublicaBons Inc

.1 ATAP' , ATARI l ARI AT >R1 ATAF ATARI A' ARI ATA ATARI A ARI ATA ATARI A \RI ATAI TARI Al 'I ATAR. Rl ATAi.

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AR , AT .TAR ■ HI AT.

■^ARI ATARI ATA''^m AT«"

,1 ATARI ,. . ATARI ATM ARI A~ Rl AT ^[ \TM -T' i AIAKI AIAI

.U ATARI Aln ATA.,1 ATARI A .Kl ATARI .. aTAR ATARI AT,

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ATARI .Rl AT/ ATARI A. i ATARI / Rl ATARI

Kl ATArtl ATA' 01 ATA"'

PARI ATARI \TAR1 ATAI

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^*R1 .ATAP' TARI A Rl ATAI TARI A Rl ATAI TARI A Rl .ATAI TARI A .RIATAk

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'II .ATAI. \RI AT,

ATARI .Rl ATAI

.ATARI , .Rl ATAI

.ATARI >R1 ATA I ATAR'

\TARI .^lARI A' ATARI

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., .aTA . .ATARI .. ,K1 ATARI ATARI .ATAK ■^ARI ATARI ATARI .AT,

,<! .ATARI .ATf'

I .ATARI

\RI ATA

I .ATARI

\RI ATA

I .ATARI

VRI ATA

I .ATARI .

\RI ATARI .ATARI .ATARI <TAR1 >'

\R1 ATA ,AK1 AlAk Rl ATARI Al

"(I ATARI ARI .ATA 1 .ATARI \R1 .ATA 1 ATARI ARI .AT<I ATAF

ari .atari

.Rl .AT.'""' ATAi .ATARI Rl AT

TARI ,A7 .ATARI

1 ATARI ATARI .ATA

TARI AT

1 ATARI

TARI ATA ATARI AI .I n \RI ATARI ATAR' TARI ATARI A' *TARI A-i"

.Rl ATARI .-. .Rl ATA"! ATAR.

ATARI TARI .A1 1 ATARI iTARI Al 1 ATARI TARI AT ' ATARI

ARI AT TARI .

Rl ATAi \TARI A (I ATAR. VTARI .A", !I .ATARI vTARl A" <1 ATAR ATARI M .AT'

...lAI rtl .ATAk.

ari .atari atari at, atari atari atari a

Rl .ATAR TARI AT Rl ATAF TARI AT Rl ATAITARI AT Rl ATAR TARI ATA. Rl .ATARI ATARI TARI .AT .OARI AI FARI ATARI

...Ah .1 ATARI A "ARI ATAR ATARI .'

Rl ATAH ,il .ATARI a

.ATARI .» .1 ATAF' ATAR,

Rl .ATAR FARI A' I ATA.

ARI ATAI ATARI .-> vRI ATA TARI .«

\TARI AT Rl ATAR ATARI ATARI ATAR

Rl ATAk .ATARI .« ARI ATA"

TARI AT Kl .ATAH .ATARI A

Rl ATAI ATARI .» ARI ATAk

.TARI A' Rl ATAR \TAR1 .ATa ..i

vRlAT/ ATARI A Rl .ATARI .ATARI ,'

ATARI ARI ATARI ARI ATARI AT*

U ATAR!AT

•TARI .ATA'

TM

,IAK. ARI AT ATARI 'Rl .»••

■H Atari graphics and sound stand in

^\ a class by themselves." Dcwid D. Thornhurg

Compute' Magazifie, Not viuher/December 1980

"Its superiority^ lies in three areas: drawing fancy pictures (in color), playing music, and printing English characters onto the screen. Though the Apple can do ail these things, Atari does them better."

Russell Walter "Underground Gtdde to Buying a Computer" Published 1980, SCELBI Publications

What computer people

are saying about Computers for people!

"The Atari machine is the most extraordinary computer graphics box ever made..!' Ted Nelson

Creative Computing Magazine, June 1980

".. .so well packaged that it is the first personal computer I've used that I'm willing to set up in the living room."

Ken Skier, OnComputing, Inc. Summer 1980

".. .well constructed, sleekly designed and user-friendly—expect reliable equipment, and strong maintenance and software support.

Videoplav December, 1980

To find out about the ATARI® 800™ Computer finst hand, a.sk your local computer dealer for a hands-on demonstration. Or call, 800-538-8547 (hi California 800-672-1404)

Listing 1 continued:

116 00

•

11 7 U 0

*

116 00

* REGS

DISPLAY

Hk.GISTtRS

11900

•

12000

0466

8D

15

HEGS

BSP

CURL

DO CR/LF

12100

0468

CE

059A

LDX

»CCL

DISPLAY ICC B A XI CKLF

12200

Q4BB

HO

E07k.

JSR

PDATAl

12300

046E

30

TSX

GE'l STACK ADDRESS

12400

046F

08

1 NX

CORRECT FDR REGS RETURN ADDHE55

12500

0470

08

T NX

12600

047 1

BD

FOCA

JSH

i)UT2HS

DISPLAY CC

12700

0474

an

EOCA

JSP

G U T 2 H s

DISPLAY

128 0 0

0477

rtD

FOCA

JSR

0 U T ? H S

DISPLAY A

1290U

0 4 7 A

BO

EUCH

JSP

U U T 4 H S

DTSPLAV X

13000

047D

CK

05A4

CURL

LUX

»CRLF

DO CARRIAGE RETUBN/LINE FEED

13100

04B0

BD

E07E

JSR

PDATAl

13200

0483

39

RTS

EXIT

13300

•

13400

0484

CE

800C

NOPE

IDX

IHCCPIA

GET PIA ADDRESS

13S00

0487

7E

03F9

JMP

SETUP

GO START COUNTER AND EXECUTE

1 3600

«

13700

t GET HEX INPUT

1380U

#

13900

048A

BD

ElAC

INHEX

JSR

INEEE

GO GET CHARACTER

14000

0480

80

30

SUBA

• t30

HEX?

14100

048F

28

10

BMI

BADHEX

NO- JUMP

14200

049*.

8 1

09

CMPA

«t09

BETWEEN 0 AND S097

14300

0493

2F

OA

BLE

□KHEX

rtS' OK

14400

0495

81

11

CHPft

ttll

A OR GREATER?

14500

0497

2B

OH

bm:

BADHEX

NO" ERROR

14600

0499

8 1

16

CMPA

• S16

r OR LESS?

14700

049B

2E

04

BGT

BADHEX

NO- ERROR

14800

049D

80

07

SUBA

t$07

ADJUST FOR A THROUGH F VALUES

14900

049F

OC

UKHEX

CLC

CLEAR ERROR FLAG

ISOOO

04A0

39

RTS

EXIT

15100

0 4A1

00

BADHEX

SEC

15200

04A2

39

RTS

15300

*

15400

•GET 0\E

BYTE OF

HEX INPUT

EXIT

WITH DlGTl IN A AND CARRY CLEAR IF OK,

15500

*

15600

04A3

8D

E5

BYTE

BSR

XNHEX

GET A DIGIT

15700

04A5

25

OA

BCS

BAUU

BAD- NOT HEX- JUMP

15800

04A7

48

ASLA

MOST SIGNIFICANT DIGIT, 50 LEFT

15900

04A8

48

ASLA

, JUSTIFY IT

16000

0 4A9

48

ASLA

a

16100

04AA

48

ASLA

16200

0 4AB

1 b

TAB

! AND SAVE IM B-PEGISTER

16 300

0 4AC

DC

BSR

INHEX

GET LEAST SIGNIFICANT DIGIT

16 400

04AE

25

01

BCS

BADB

IF INPUT IS BAD- JUMP

16500

O4B0

1 B

ABA

COMBINE BUTH in A

16 600

04B 1

39

bADB

RTS

EXIT

16700

*

16800

« BADDR.

BIjlLD ADDRESS, RESULT

In

SAOOC

AND X IF GOOD, ELSE CARRY SET.

16900

*

170OO

04B2

H D

EF

baodr

BSR

BJTK

GET HEX bYTE

17100

2 5

OD

BCS

AUBAU

JUMP IF BAD

17200

04B6

H7 (

AOOC

ST A A

AODR

SAVE BYTf

17 300

0 4B9

80

£8

BSP

BYTE

GET SECOND BYTF

17 400

0 4BB

2 S

0 6

HCP

ADBAD

JUMP IF BAD

17500

U 4BD

R7

AOOD

STAA

ADDR*1

SAVK IT

17600

04C0

FK

AOOC

LUX

ADDR

GET IN X

17700

04C3

39

AnBAD

RTS

EXIT

17900

«

179u0

* TRACt.

PROCESSING. COMMAND

FOpi^AT! 1XXXX, np rxxxx.NN

16 000

«

tiHtPF

T IS

THE COHfAND CHARACTER

18100

«

XXXX

IS A KllJh-DIGiT HEX ADDKtSS

13 20(1

WN IS

A DIGIT TkAP C00MT = S7K "lAX ,

1 B 300

•

ThACE

hUDE 1S SET

1ITH

THIS

COMMAND, STEP CM^'iAND SIARTS RUN.

1 b 4U0

»

thh: prublem program

1»ILL RUN

UNTIL PE^•0^■(S) HAS E'^CfjUnTtREU

1 S R 11I

1 a 3 u u

«

AODRF.SS XXXX MN TIMES,

WHEN

IT "ILL REll^Rii OPERATOR CONTROL,

1B 600

*

AUDkESS XXXX N.IJ3T

BF

thr; audrfss nr the first byte uf an INSIWUCTIUN,

I 8700

♦

IJilTr

THAT Zf.HO IS

A

IJISALI.llWEti VALUt M.iP NN IM INPUTt

18 8 00

*

TXXXX

, KUHr-< SETS

Tn

01 AHT(jMAl ICALLV,

16 900

0 4C 4

8 D

EC

TRUCE

BSR

BADDR

GO GET TRACE ADDBFSS

19000

04C6

2 5

95

BCS

BAD

BAD INPUT

19100

0 4C d

PF

A 079

SIX

lADDR

19200

0 4C B

h n

ElAC

JSR

INEEE

GfcT PkHIOD op COMMA

19300

04Ct

2E

CMPA

.

PECIDD?

19400

0400

27

OF

BtO

SEl'ONF.

YES- SET TFLAG TO ONE

19500

04D2

81

2C

C"PA

«' ,

COMMA?

196(10

0*1^4

26

B7

UNK

B A1/

NO- BAD 1N(-UT

19700

0 4Uo

»D

Cb

bSH

bv rt

IT IS COFMA- GEI LOOP COUNT

19800

0408

25

83

BCS

HAD

19900

n4DA

27

81

HEQ

BAD

2000u

040C

B7

4078

SETT

STAA

TFLAG

SET IN TRACE FLAG

20100

04DF

20

81

NEXT2

BRA

NEXTl

GO GET A COMMAMD

20200

04tl

86

01

SETONE

LDAA

*$01

20300

04E.3

20

F7

BRA

StlT

Listing 1 continued on page 342

340 May 1981 © BYTE Publications Inc

TRS-80 owners

Explore new worlds

with chatterbox:

The MICROMINT INC. introduces its latest data communications product, the "CHATTERBOX." The CHATTERBOX is a unique packaging combination of the presently available COMM-80 I/O interface for the TRS-80* and an acoustic modem. This one box is all that is required to turn even a barebones 4K TRS-80 into a full timesharing terminal. ^

The CHATTERBOX includes a built-in programmable .i^^B 50-19200 baud serial port, a yj^^l Centronics compatible parallel l^^^ printer port, a 300 baud acoustic originate modem, and ^^^H a spare TRS-BUS expansion , connector. It comes complete |^H- \ with power supply, ribbon ^^Hi cable and connector, user's manual, and smart terminal ^^^H software for immediate ^^^1 operation. When the modem ^I^H is in use, the complete data ^wPI conversation is automatically ^ Ji

routed to the serial output ^ port and parallel port where it can be

logged on a printer. ^^SHRi^^^

The CHATTERBOX is the only peripheral needed to allow a TRS-80 to communicate with timesharing systems such as Micronet and the SOURCE. In addition, CHATTERBOX can be used simply to provide an address selectable serial and parallel port.

It is completely hardware amd software compatible with existing TRS-80 products and connects \ either to the keyboard connector or screen printer port on the RS

tExpansion interface. It does not require the RS Expansion interface for operation. chatterbox:

$279.95

• Full 8-bit parallel port.

• RS-232-C serial port

(upto 19,200 baud). • Acoustic modem. • TRS-BUS connector for future expansion. Connects to Keyboard or E.I. • Includes terminal software.

• Users manual.

• Power supply

MAIL ORDER OR INFORMATION WRITE OR CALL:

The MicroMint Inc. 917 Midway Woodmere, NY 11598 Dealer inquiries invited.

CALL:

516-374-6793

THE INTERFACE CONNECTION

TRS-80 is a trademark of Tandy Corporation

Listing 1 continued:

20400

• STEP

COMMAND PRtlCESSIMG,

CAUSES TRANSFER OF CONTROL In APDRESS,

20500

CtJMMAND

FORMATt SXXXX DP S,

20600

#

WHFCF XXXX IS A FOUR DIGIT HEX ADORESS,

20700

•

SXXXX FORI- SETS NF.« CIJPREM ADDRESS

20800

*

S, FUPM

STARTS RUN AT CUHKEnT ADDRESS,

20900

•

21000

04t5

80

CB

STEP

BSR

BAODR

GO GET ADDRESS

21100

04F7

25

9K

BCS

NOPE

IF NOT HEX- ASSUME PERIOD

21200

04t.9

8D

7(j

BSP

SETAD

ELSE PUT APDRESS IN STACK

21300

()4tci

71?

0437

jmp

NOT

DISPLAY AND GET NEXT COMHAND

21400

U4t.E;

U 1

Nlip

21500

04KF

01

NOP

21600

04)'°0

01

NIJP

21700

04F1

01

NOP

21800

» GO Cn.MMAND PFUCESSING, CAUSES FXIT FRUw DFMUnCS) t-W'". CYcijt CMUMLi*

21900

*

HALTED, USE "mEn FI^I,SHH> ».IT>' DFBmSli ING.

22000

•

CONTROL IS PASSED 10 THE CURhKNT AMDHESS RbACnhD

2210U

»

WHILE STEPPING OH TRAC^^G.

22200

04^2

3B

GO

PTl

EXIT fnOf DEMONcs)

22300

* DISPLAY

CUHMANI)

PROCESSnc, DISPLAYS 15 INSTRUCTIONS FROM MEMORY IK

22400

■•

DISASSEMhLED FORM,

22500

•

CUvMANIl FOH^<S; DXXXX UR D,

22600

•

■"HERE XXXX :s 4 4 DICII HEX ADORtSS

22700

D. CAUSES DISPLAY III STA><T *1TH THE CURREUT

22800

*

INSTRUCTION

22900

04t3

7E

0450

HAP

JMP

BAU

230U0

04F6

Hh

OE

DISPLA

1,0 A A

• SUE

SFT UP LINFS FOR PISASi

2310U

04K8

B7

AO 7 7

STAA

LINES

23200

04KH

BD

H5

bSR

8ADDR

GET ADDRESS

23300

0 4KD

24

06

BCC

SHO«l

IF NO ERROR ON FURY- BRANCH

23400

04tT

30

■isx

GET ADnpESS FROM STACK

23500

(1500

f.f;

05

LDX

5,X

23600

0502

FF

iUOC

STX

AUDK

,AM> SET FOR DISASSKMHLER

23700

0505

B6

10

SHOW

L.UAA

HSIO

HOME lip

23S0O

0507

BD

ElOl

JSR

OUTEEE

23900

O5OA

80

62

BSH

SHOLIN

GO DISPLAY INSTRUCTION

24000

05OC

20

01

Bra

NEXT2

GET AnCIiHER CUWMAhD

24100

» KEGISTeH

DISPLAl

, THE REGISTERS IN THE STACK APE DI SPLAY,

24200

COMMAND

FOHMJ R

24300

»

24400

OSOE

HI)

04b6

SHDREG

JSR

REGS

DISPLAY REGISTERS

24500

0511

7E

0441

BACKUP

JMP

COMQhl

GO GET AlvOTHE COMMANO

24600

24700

# SUPPIIRT

SUBRUUTINE- (ill

INPUT AND PHEPAPE X REGISTER

24800

*

24900

0514

BU

80

BSR

BYTE

GET INPUT BYTE

25000

0516

25

04

BCS

GAG

BAD VULUE?

25100

0518

30

TSX

SET VALUE IN STACK

2520U

0519

08

INX

ADJUST ADDRESS FOR BEING In A SUHRuUTInk

25300

051 A

08

INX

25400

obia

39

RTS

25500

05 IC

31

GAS

INS

25600

051D

31

INS

25700

obit.

20

D3

BRA

OAB

25800

♦

25900

* SET CnwDITION CUOE REGISTER, COMMAND FDPHi CXX

ibOOO

«

WHERE XX IS A 2-DIGIT HEX VALUE THAT

26100

«

THE CC REGISTER IN THE STACK 1ILL BE SET

26200

*

TO.

26300

•

26400

0520

BD

F2

RSETC

BSR

BVN

GET INPUT BYTE

26500

0522

A7

00

SGTRGG

STAA

X

26600

0524

20

B9

BRA

NEXT2

GO GET ANOTHER COMMAND

26700

«

26800

* SET B

•REGISTER,

COMMAND

FORMI BXX

26900

»

27000

0526

BD

EC

RSETB

BSR

BYN

GET INPUT BYTE

27 100

0528

08

BSETS

INX

27200

0529

20

F7

BRA

SETREG

27 300

•

• SET A

-REGISTER,

CUMMAND

rORMt AXX

•

27600

052B

8D

E7

KSETA

BSR

BYN

27700

0520

08

INX

27800

052E

20

F8

BRA

BSETS

27900

• SET X

-REGISTER.

COMMAND

FORMATI XNNNN

28000

•

rtHERE NNNN IS A 4-OIGIT HEX VALUE

28100

*

28200

0530

BD

04R2

RSETX

JSR

BADDR

GET 4 DIGITS

28300

0533

25

BE

BCS

DAB

BAD INPUT?

28400

0535

30

TSX

NO- GET STACK ADDRESS

28500

0536

09

DEX

SET X VALUE IN STACK

2B600

0537

0 9

DEX

28700

05ja

09

DEX

28800

0539

8D

28

BSR

SETS

Listing 1 continued on page 344

342 May 1981 © BYTE PublicaUoro bic

DEALERS: By now you know that it takes

SOFTWARE

TO SELL

COMPUTERS

and International Micro Systems can provide you with the largest selection of quality business applications ever developed for the microcomputer industry.

If you are just looking for a G.L., A/P, and Payroll, you can find them in a dozen ads in this magazine. But thers's a much bigger market for micros out there than that. Wherecan you find a fully interfaced Wholesale/Retail Distribution System? How about Manufacturing Inventory Control including Production Scheduling & Control. See that one anywhere else? Maybe your market is Medical/Dental and IMS has the full systems there too. You can't sell computers without software and IMS has the finest selection of software avail able for you. Each system has been developed by the IMS professional staff and we support what we sell.

But thats not all. International Micro Systems has the strongest dealer marketing plan in the industry. With our

^245 Dealer Demo System.

we put all the software shown below in your office or store ready to demo to your prospects and we include the promotional material and our unique video sales presentation to help you move systems. Give us a call or drop us a card and let us show you what selling business systems should be all about.

Financial Systems

GL, A/P, A/R Payroll

Cash Receipts/Disb.

Job Costing

Mailing List Mgmt. Medical/Dental

Ottlce .Scheduler

Patient Billing & A/R

Insurance Forms Governmental/Educational

Student Record Keeping

and Scheduling

Fund Accounting

Wliolesale Distribution System

Purchasing & Receiving Inventory Control Invoicing & Receivables Salesman Comm. Reporting Backorder Management Manufacturing Inventory Control Finished Goods Inventory Mgmt. Parts Inventory Mgmt. Parts Purchasing & Receiving Bill of Material Production Scheduling

INTERNATIONAL IICRO

S

YSTEMS

'■

For details on our demo special, contact us at: 8425 Quivira Road, Lenexa, Kansas 66215 Phone: (913) 888-8330

Circle 201 on Inquiry card.

Listing 1 continued:

28900

053B

20 A2

NEXT3

bPA

NEXT2

29000

• PATCH COMMAND

PHOCeSSOR.

COMMAND FORMATi PXXXXiNN NN NN ,,,,(CR)

29100

#

WHERE XXXX IS A 4>DIGIT t^EX ADDRESS

29200

ANU NM IS A 2-DIGIT HEX VALUE

29300

#

tNTEH

AS MANY 2

DIGIT VALUES AS NEEDED* THEN TERMINATE STRING

29400

wIIH

A CAHRIAGE

RETIJBM, EACH NN VALUE IS PLACED IN MEMUrY AS

29500

II IS

ENTERED!

IIVLESS AN ERROR IS MADE, THEN THE NN VALUE

29600

#

CONTAINING THE

Error is rejected aiuD is not stored.

29700

29BO0

(lb 3D

BD 04B2

PATCH

JSR

BAODF

GET ADDRESS

29900

0540

25 PI

BCS

DAB

jnwp It" NOT HEX

300OO

0542

FF 4 07 5

GETWOR

5TX

XSAV

SAVE X EOP LATER

JO I 00

0545

BD 04A3

GETS

JSP

BYTE

GET 2 DIGIT VALUE

30200

0548

25 OD

bCS

WHAT

JUMP IF NOT HEX

30300

0S4A

FE A075

tiDX

XSAV

RESTORE X

30400

0540

A7 00

STAA

X

.AND STORE THE VALUE

30500

U54F

OH

INX

POINT TO NEXT LnCATlUN

30600

055 0

86 20

I.OAA

t'

SPACE BETV>tEN INPUTS

30700

0552

BD ElOl

JSK

UUTEEE

30800

05S5

20 EB

BRA

GETMdR

GO GET MOPE INPUT

30900

0557

8 8 DO

WHAT

EURA

«6DD

INPUT Ni)T HEX" CARRIAGE CODE?

31000

0559

27 EO

bKU

Nt)l,T3

Jlir^P IF yES

31100

055B

88 21

EDRA

• $21

c n M A ?

31200

055D

27 Eb

BEU

GETS

0u^'P ih iE.s

31 300

05hF

20 92

bPA

DAH

,EL5t. ERPUH IF iujT

il4(J0

315rio

SURUUTlsit" MOVK

ADDRESS INTO STACK

3lbijil

31 7 01)

056 1

3u

TSX

PUT IriE ADDRESS JU THE STACK

3 1 aou

0562

08

INX

31900

0563

B6 AOOC

.SETS

liHAA

AODH

32000

0566

A7 06

STAA

b.X

3210(1

0568

H6 AOOU

LDAA

ADDH+1

3 2 2 M 0

U56B

»7 07

STAA

7»X

32300

056n

39

BTS

32400

32500

* suppuht

SUBROUTlUE" SET

APPEMlAGE ADDRESS AND CALL DISASSEMBLER

3 26 00

32700

ij56E

C K 0 1 A 4

SHijLlN

LDX

lAPP

SET APPENDAGE FnH DISASSEMBLER

32?rj;i

05/1

STX

APPhU

3 2 90 0

0574

"0 U 01b

JSR

NEXTl.

GO TO DlSASSErtBLFR

33000

05 7 7

39

HIS

33100

* COMMAND

TABLE,

EACH tNTKV IS 3 hVTP:S LfJNG, THE FIRST BYTE IS THE ASCII

33200

COMMAND CHARACTER, THE NEXT 2 PYTI-S ARK THE PROCESS

33300

ADI.)RF:.SS,

THE TABLE IS TSRlVI^»TfcD MTH A BYTE OF ZKHUS.

33400

33500

05 7 8

S 3

COMTftH

ECC

/S/

STEP COMMAND

33600

0579

04E5

FOB

STEP

33700

0578

54

FCC

/T/

TRACE COMMAND

33800

057C

04C4

FDB

TRACE

J39u0

0571;

52

FCC

/R/

REGISTER DISPLAY

34000

057F

050E

FDB

- SHOREG

34100

0581

47

FCC

/G/

GO COMMAhf

34200

0582

04F2

FDB

GO

34300

0584

44

FCC

/D/

DISPLAY COMHAM)

34400

0585

U4F6

FDB

DI5PLA

34500

0587

4 3

FCC

/G/

SET crjf-DITinw criPES

3 4 6 u 0

U588

05/iU

FOB

RSETC

34700

058A

4 1

FCC

/A/

SEl A-REGISTtK

34800

058B

0S2B

FUB

RSETA

34900

058D

42

FCC

/B/

SET B-REGISTEB

35 000

n e ? ^ u 3 * t>

FDB

HSEVB

35100

0 59 0

5 8

FCC

/X/

SET X-REGISTER

0591

I' 3 J u

FDB

RSETX

35 300

0593

50

FCC

/P/

PATCH

^5400

0594

05 3D

FDB

PATCH

1 ^ C n

J 3 3 U ^'

0596

0 0

FCB

Of 0, 0

SPACE FOR PATCHING AN ENIRY

35600

0597

00

35 700

0598

00

35 8 00

0599

00

KCB

0

END OF TABLE

35900

: lOENTIEICATION

J D u u u

05 9 A

4 3

FCC

/CC B

A X/ REGISTER ID LINE

059B

36200

059C

20

36 300

0590

42

36400

059E

20

36500

059F

20

36600

05A0

41

36700

05A1

20

36800

05A2

20

36900

05A3

58

37000

05A4

OD

CHLF

FCB

«OD,aOA

,4 CAPRIAGE RETUHN/LINE FEED

37100

a5A5

OA

37200

0SA6

04

37300

END

Listing 2 starts on page 346 Listing 3 is on page 358

344 May 1981 © BYTE PublicaUoiu Inc

r

Wete known for our fine print.

voice fro« V""

-11 count aty ,

until y^-^y on..

Epson.

The type you get out of most printers you wouldn't send to your maiden aunt, much less use for your important correspondence. And up to now, in order to get a dot matrix hardcopy you could really call correspoiidence quality, you had to spend on the high side of a thousand bucks. Not any more.

The Epson MX-80 challenges any dot matrix printer anywhere to match our type at our price. Or even come close.

Our emphasized print mode gives you a tacksharp, clean, easy-to-read face with true descenders—at a fraction of the price of daisy wheel printers. We give you a user-defined choice of twelve different weights and sizes of letters in 40, 80, 66 or 132 columns. We give you adjustable tractors so you can do anything from labels to memos to manuscripts. Fast and clean.

But if you think print quality is the only thing we have

to sell, you're wrong. The MX-80 may be the most revolutionary printer to come out in the

past ten years.

For starters, it features the world's first disposable print head—after it's printed between 50 and 100-million characters, just throw it away. A new one costs less than $30 and you can change it yourself with one hand. Plus, the MX-80 prints bidirectionally and 80 CPS with a logical seeking function to minimize print head travel time and maximize throughput. Finally — and this is the best part — you can buy an MX-80 right now for less than $650.

And that's what we call a lot of fine print for the money.

EPSON

EPSON AMERICA, INC.

23844 Hawthorne Boulevard • Torrance, CA 90505 • (213) 378-2220

Circle 152 on Inquiry card.

BYTE May 1981 345

Listing 2: The disassembler routine included as part of DEMONS. The packed-mnemonic table and format table occupy much space.

00100 00200 0030U

00400 00500 00600 00700 00800 00900 01000 01100 01200 0130U 01400 015 0 0 01600 01700 OIBOO 01900 02000 02100 02200 02300 02400 02500 02600 02700 02800 02900

NAM

DISASM

AUTHORl A,I. HALSEMA DATE! 10-28-1977

OBJECT MACHINEI SWTPC 6B00

PROGRAM NAME! DISASSEMBIiER VERSION 1,1

OPT

0

0000

ORG

soooo

E047

BADDR

EQU

SE047

AOOC

ADUR

EQU

8A00C

E07E

PDATAl

EQU

$E07E

tt

• QPEHATDR

INTERf'ACE

001)0

BD

E047

#

START

JSR

BAUDK

0C03

86

OF

LDAA

•15

0005

B7

A077

STAA

LINES

0008

CE

0169

LDX

•ERASE

OOOB

BD

E07E

JSR

PDATAl

OOOE

CE

01A4

LDX

• APP

001 1

FF

A07C

STX

APPND

0014

80

02

BSR

NEXTL

0016

20

£8

BRA

START

GET DUMP ADDRESS KROM OPERATOR VIA MIKBUG SET » OF LINES TO DUMP

ERASE CRT SCREEW

SET APPENDAGE ROUTINE ADDRESS

DISASSEMBLER, ENTER WITH DISPLAY START ADDRESS AT SAOOC,

NUMBER OF LINES TP DISPLAY AT LABEL 'LINES', SET ADDRESS or APPENDAGE ROUTINE AT A07C ENTER VIA JSR,

EACH TIME A LINE iS READY, APPENDAGE REClEVES ClINTROL VlA JSR,. RETURN VIA RIS,

03000

tt

EXIT WITH SAOOC

CONTAINING ADDRESS OF NEXT

03100

tt

INSTRUCTIO'I, LOCATION

SA04A CONTAINING 32

03200

tt

BYTES OF ASCII

TEXT TERMINATED BY CH,LF,04,

03 300

tt

LOCATION 'LINES

' WILL

CONTAIN ZEHO, \

0 3 400

0 0 1 d

FF.

AOOC

nextl

AD rip

<",ET ADDRESS OF DATA

03500

001b

A6

00

LDAA

X

GET DATA BYTE

03600

00 ID

CE

A06B

LDX

•MORKA

03700

0020

A7

03

STAA

BYTE.X

SAVE IT

03800

0022

5E

CLRP

NOW MULTIPLY BY 2

03900

002 3

48

ASLA

04000

0024

59

ROLB

04 JOO

0025

AB

02

ADDA

TAD+1,X

ADD MNEMONIC TABLE ADDRESS

04200

0O27

E9

01

ALCB

TADjX

04 30U

0029

A7

07

STAA

eASEt1,X

SAV the DISPLACEMENT IMTU TABLE

04400

002b

f:7

06

STAB

BASErX

04500

0020

A6

03

LDAA

BYIt.X

GET HIGH OI-DER fJYBRLE

04601;

002F

44

t.SRA

04700

0 0 31)

44

LSRA

BIGHT JUSTIFY IT

04800

0031

44

LSRA

AND MULTIPLY BY 2

04900

0032

h4

FE

ANDA

»SFE

05000

0034

5E

CLRR

0 5 10 0

003S

(IB

0 5

AODA

EAD+ 1 ,X

ADD BASE OF FLAG TABLE

05200

0037

E9

0 4

ADC6

FAU,X

05300

0039

A7

09

STAA

FLAGA^l.X

SET POINTER INTO FLAG TABLE

05400

OOJB

E7

08

STAB

FLAGA.X

05500

00 3D

CE

A04A

LDX

• LINE

BLANK THE DISPLAY LINE

05600

U 0 4 0

C6

IB

LDAB

»27

05700

0042

86

20

LDAA

US 20

05900

0044

A7

04

BLOP

STAA

4,X

05900

0u4b

OH

INX

0600CI

0047

5A

DECEl

06100

0U4B

26

FA

BNE

BLOP

06200

004A

86

04

LDAA

»4

SET tOL BARKER

06300

0U4C

A7

05

STAA

5, X

06400

0U4t,

CE

OOOA

, LUX

•SODOA

SET CRLE IN LINE

065U0

005 1

FK

AObS

STX

LINE+30

06600

0054

FE

A071

LDX

WBAS

GET THE PACKED MNEMONIC

06700

0057

Ab

0 0

LDAA

X

AND EXPAND INTO DISPLAY LINE

ObROO

0059

H4

7F

AUDA

«S7F

0690U

OOSri

Eh

01

LOAB

1»X

07 0 0 0

005D

44

LSRA

07100

005E

56

RORR

0720(1

005K

44

LSRA

07300

0060

56

RORR

07400

006 1

SR

40

ADDA

*a40

0 7 5 0 0

006 J

b7

A058

STAA

OPER

07600

0 066

54

LSRH

07700

0067

54

LSRB

07800

0068

54

LSRB

07900

0069

CP

40

ADDB

• S40

0 e 0 u 0

OObB

r7

A059

STAB

UPER+1

08100

006E

A6

01

LDAA

1»X

08200

0070

84

IF

ANOA

»tlF

08 300

0072

8B

40

ADDA

• $40

08400

0074

87

A05A

STAA

OPER+2

08500

00 77

A6

00

LDAA

X

GET HI BYTE AGAIN

08600

0079

81

18

CMPA

• 818

TEST FOR FCB MNEMONIC

08700

007B

26

05

BNE

NFC

NOT FCB

06800

007D

CE

03CB

LDX

•FFLAG

IS FCB- SET FCB FLAG ADDRESS

0S90U

0080

20

26

BRA

OFF

Listing 2 continued on page 348

346 May 1981 © BYTE Publications Inc

TM

When Is Not Enoi^: CP/M-86~aiidCMSIC/8(i

"In 1977 Compiler Systems, Inc. introduced CBASIC" as a CP/M® programming language. It quickly became the most widely used BASIC dialect Since then CBASIC has been adapted for use on systems supporting MP/M™ and TRSDOS."

"At Compiler Systems we learned the lessons of the past well. So well, that in the relatively short time we've been in the software business, we managed to make history ourselves. In fact, CBASIC is the standard for CP/M-based business systems."

— Gordon Eubanks, CSI president

Today CSI offers CBASIC/86 designed for 16-bit microcomputer-based systems running under CP/M-86. CBASIC/86, now available worldwide, is based on concepts first used by CBASIC including such businessoriented features as: BCD arithmetic with fourteen-digit precision; full format control of printed reports; ran^ dom and sequential records of any length (not limited to 256 bytes); aids to structured design, i.e. multiple line functions and control structures as well as excellent filehandling and stringing capabilities.

But perhaps the best of CBASIC/86 becomes clear when you're using it. To learn more about CSI's commitment to support 'i^.^ CBASIC/86 and CP/M-86 call

(213) 355-1063 and discuss putting ; V -M CBASIC/86 on your system.

Send this coupon today, we'll send details that go a long way toward answering your questions.

Name/Date. Company — Address

City/State/Zip.

OEMs contact us for pricing

m

WORLDWIDE DISTRIBUTION FROM

Compiler Systems, Inc., 37 N. Auburn Ave., P.O. Box 145 Sierra Madre, CA 91024, (213) 355-1068

Circle 431 on Inquiry card.

Listing 2 continued:

09000 •»♦«»»«»»•♦•»»#»»•»»•»»•»#»»#•«••••••••••••••«•♦♦•

09100

0082

F6

A06E

NFC

LDAB

WBYT

TEST FOB EXCEPTIONS

09200

0085

CI

37

' CMPB

»S37

PULB7

09300

0087

26

05

BNE

TPSH

09400

0089

CE

03B5

LDX

• PULb

09500

008C

20

lA

BRA

OFF

09600

008C

CI

33

TPSH

CMPB

«(33

PSHB7

09700

0090

26

05

BNG

TBSR

09800

0092

CE

03B5

LDX

*PULB

09900

0095

20

11

BRA

OFF

10000

0097

C8

80

TBSR

EORB

DtSD

BSR?

10100

0099

26

05

BNE

SET

10200

009B

CE

03AF

LDX

iBSR

10300

009E

20

08

BRA

OFF

10400

•••••••»«••«••••••«•••»•*•«•••«»••*•••*••»••••*•*«

lOSOO

OOAO

SET

EQU

•

10600

OOAO

FE

A073

tDX

MFLG

GET FLAG ADDRESS

10700

00a3

85

80

BITA

»S80

TEST FLAG BIT

loeoo

00A5

27

01

BEa

OFF

BIT IS OFF

10900

00A7

08

INX

BIT IS ON- POINT 10 2ND FLAG

11000

00A8

A6

00

UFF

LDAA

X

GET THE FLAG

11100

OOAA

B7

A05B

STAA

FLAGD

.AND SAVE IT

11200

OOaD

CE

A04a

LDX

iAADR

POINT ASCII ADDRESS IN LINE

11300

OOBO

B6

AOOC

liOAA

ADDR

GET CURRENT ADDRESS

11400

0OB3

8D

2A

BSR

CVASC

CONVERT TO ASCII

11500

0085

B6

AOOD

LDAA

ADDp+l

SAME roR Low BYTE

11600

00B3

80

25

BSR

CVASC

ilTOO

QOBA

B6

A06E

LDAA

WBYT

GET CURRENT BYTE

11800

OOBD

08

INX

LEAVE SPACE BETWEEN ADDR,+ DATA

U900

008E

80

IF

BSR

CVASC

CURRENT BYTE TO ASCII

12000

OOCO

F6

A06B

LDAB

FLAGD

GET FLAG DATA

12100

00C3

C4

03

ANDB

• 13

SAVE ONLY INSTRUCTION LENGTH

12200

00C5

F7

A07B

STAB

SIZE

SAVE IT

12300

O0C8

08

INX

12400

O0C9

FF

A075

CliOP

STX

XSAV

SAVE POINTER INTO DISPLAY LINE

12500

OOCC

FE

AOOC

LDX

ADDR

GET DATA ADDRESS

12600

OOCF

08

INX

12700

OODO

5A

DECB

COUNT BYTES

12800

0001

27

10

BEO

NMR

NO MORE

12900

00D3

A6

00

IiDAA

X

GET DATA

13000

00D5

rr

AOOC

STX

ADOft

13100

0008

FE

A075

LDX

XSAV

13200

0008

8D

02

BSR

CVASC

AND PUT IN DISPLAY LINE AS OBJ,

13300

OODD

20

EA

BRA

CLOP

13400

OODF

7E

018C

CVASC

JMP

TOASC

13500

00E2

FF

AOOC

NHR

STX

AODR

X NOW POINTS TO NtXT DATA

13600

00E5

B6

A06B

LDAA

FLAGD

GET FLAG DATA

13700

OOb'8

85

40

BITA

• 840

SET REGISTER A?

13800

OOEA

27

07

eEO

NOTA

NO .

13900

OOEC

86

41

LDAA

• 1 A

YES" ADD TO ASCII MNEMONIC

1400U

OOEE

B7

A05B

SETR

STAA

OPEH+3

14100

OOFl

20

08

BRA

FORM

14200

OOFJ

85

80

NOTA

BITA

• 880

SET REGISTER B?

14300

OOP'S

27

04

BEQ

FORM

NOB MQ RvGISTFR SYMBOL

14400

00F7

86

42

LDAA

• * B

YES

14500

O0F9

20

F3

BRA

SETH

14600

OOFB

CE

A05E

FOHM

LDX

• ARG

U700

OOFE

B6

A06B

LDAA

FLAGO

14800

0101

44

LSRA

14900

0102

44

LSPA

15000

0103

H 4

u t

11 ^ * f

15100

OlOb

2 7

OF

BEO

n T 4DT.V

15200

0107

UCL A

15300

0108

01

« /

1A

15400

OlOA

4A

15500

OlOH

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348 May 1981 © BYTE Publications Inc

Use all standard peripherals and existing software

When you buy PMC-80 you get hardware and software compatibility with the most popular microcomputer system in the worlds that means thousands of disk and cassette based programs and all kinds of peripherals are instantly available!

PMC-80 has configurations that give the computer enthusiast a way to grow from a STARTER system in affordable increments. Begin at a low $675 for the basic 16K level II system and grow to the complete 48K memory system pictured above with two floppy disks for less than $3000.

FASTLOAD option inputs short programs as fast as "disk" from ordinary.

standard format cassettes. Fast, reliable and economical!

PMC-80 COMMUNICATOR option provides interface to modems and parallel port printers. Take your pick of peripherals for communication with electronic bulletin boards and low cost timeshare services via phone lines from your home or business.

PMC-80 EXPANDER option provides the most powerful configuration with a total of 48K memory, provision for 4 mini-floppies, printer interface, RS232C communications interface, plus a slot for the popular S-100 boards.

Sold through computer stores.

Personal Micro Computers, Inc.

475 Ellis Street, Mountain View, CA 94043 (415) 962-0220

Circle 324 on inquiry card.

BYTE May 1981 349

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Listing 2 continued on page 352

350 May 1981 © BYTE PublicaHoM Lie

***** ************************** *T!rTi^T!r*******««*#**«***

4MHZ, DOUBLE DENSITY,COLOR&B/W GRAPHICS. .THE LNW80 COMPUTER

When you've compared the features of an LNW80 Computer, you'll quickly understand why the LNW80 is the ultimate TRS80 software compatible system. LNW RESEARCH offers the most complete microcomputer system at an outstanding low price.

We back up our product with an unconventional 6 month warranty arid a 10 days full refund policy, less shipping charges.

LNW80 Computer SI,200.00

LNW80 Computer w/BSW Monitor & one 5" Drive $1,664.00

All orders must be prepaid, CA residents please Include 6% sales tax. Shipping and handling charge of $15.00 must be included with every order. * TRS80 Product of Tandy Corporation. ** PMC Product of Personal Microconputer^ Inc.

COMPARE THE

FEATURES AND PERFORMANCE

TRS-80*

FEATURES

LNW80

PMD*80**

MODEL III

PROCESSOR

4.0 MHZ

1,8 MHZ

2.0 MHZ

LEVEL ri BASIC INTERP.

YES

YES

LEVEL III BASIC

TRS30 MODEL 1 LEVEL II COMPATIBLE

YES

YES

NO

48K BYTES RAM

YES

YES

YES

CASSETTE BAUD RATE

500/1000

500

500/1500

FLOPPY DISK CONTROLLER

SINGLE/ DOUBLE

SINGLE

SINGLE/ DOUBLE

SERIAL R5232 PORT

YES

YES

YES

PRINTER PORT

YES

YES

YES

Kt.nL 1 int LLULK

YES

YES

24 X 80. CHARACTERS

YES

NO

NO

VIDEO MONITOR

YES

YES

YES

UPPER AND LOWER CASE

YES

OPTIONAL

YES

REVERSE VIDEO

YES

NO

NO

KEYBOARD

63 KEY

53 KEY

53 KEY

NUMERIC KEV PAD

YES

NO

YES

B/W BRAPHICS, 128 X 48

YES

YES

YES

HI-RESOLUTIOn B/U GRAPHICS, 480 X 192

YES

NO

NO

HI-RESOLUTION COLOR GRAPHICS (NTSC),

128 X 192 IN 8 COLORS

YES

NO

NO

HI-RESOLUTION COLOR GRAPHICS (RGB),

384 X 192 IN a COLORS

OPTIONAL

NO

NO

WARRANTY

6 MONTHS

90 DAYS

90 DAYS

TOTAL SYSTEM PRICE

$1,664.00

$1,840.00

$2,187.00

LESS MONITOR AND DISK DRIVE

$1,200.00

$1,375.00

LNW80

• BARE PRINTED CIRCUIT BOARD i MANUAL

$89.95

The LNW80 - A high-speed color computer totally compatible with the TRS-80*. The LNW80 gives you the edge in satisfying your computation needs in business, scientific and personal computation. With performance of 4 MHz, Z80A CPU, you'll achieve performance of over twice the processing speed of a TRS-80*. This means you'll get the performance that is comparable to the most expensive microcomputer with the compatibility to the world's most popular computer (TRS-80'>) resulting in the widest software base:,

FEATURES:

TRS-BO Model 1 Level II Software Compatible

. High Resolution Graphics

. RGB Output - 384 x 192 in 8 Colors

. NTSC Video or RF MOD - 128 x 192 in 8 Colors

. Black and White - 480 x 192

. 4 MHz CPU

. 500/1000 Baud Cassette

. Upper and Lower Case

. 16K Bytes RAH, 12K Bytes ROM

. Solder Masked and Sllkscreened

LNW SYSTEM EXPANSION

. BARE PRINTED CIRCUIT BOARD

AND MANUAL

WITH GOLD CONNECTORS ...

S69.95 584.95

The System Expansion will allow you to expand your LNH80, TRS-80*, or PMC-80** to a coinplete computer system that is still totally software compatible with the TRS-SO* Model 1 Level 11.

FEATURES:

32K Bytes Memory 5" Floppy Controller Serial RS232 120ma I/O Parallel Printer Real Time Clock Screen Pri nter Bus On Board Power Supply Solder Masked and Silkscreened

KEYBOARD

LNH80 KEYBOARD KIT $84.95

Ttie Keyboard Kit contains a 63 key plus a 10 key, P.C. board, and remaining components.

LNW RESEARCH

CORPORATION

14661-C MYFORD RD. TUSTIN CA.92680

LNDoubler

Assembled and Tested

$149.00

Double-density disk storage for the LNW Research's "System Expansion" or the Tandy's "Expansion Interface". The LNDoubler™ is totally software conpatible with any double density software generated for the Percom's Doubler***. The LNDoublerTM provides the following outstanding features,

. Store up to 350K bytes on a single 5" disk . Single and double density data separation . Precision write precompensation circuit . Software switch between single and double density , Hardware override into single density only . Easy plug in installation requiring no etch cuts, juiqjers

or soldering . 35, 40, 77. 80 track 5" disk operation 120 day parts and labor Warranty *** Doubler is a product of Percom Data Cumpany, Inc.

DOS PLUS 3.2D $95.00

Micro Systems software's double density disk operating system. This operating system contains all the outstanding feateires of a well developed DOS, with ease in useability.

LNW DATA SEPERATOR

- Assembled and Tested $17.95

The LNW Data Separator provides you with a reliable and inexpensive means of solving your disk data read error problems for your 5" single density drives. Compatible with both the LNW System Expansion and Tandy's Expansion Interface. iSome soldering Is required.

CASE

LNW80 CASE $84.95

The streamline design of this metal case will house the LNW80, LWN System Expansion, LNW80 Keyboard, power supply and fan, LNOoublerTM, or LNW Oata Separator. This kit includes all the hardware to mount all of the above. /^(),J $12.00 for Shipping

PARTS AVAILABLE FROM LNW RESERARCH 4116 - ZOOns RAM

6 chip set $26.00

8 chip set $33.50

16 chip set $64.00

24 chip set $94.00

32 chip set $124.00

LNH80 "Start up parts set" LNW80-1 $82.00

LNW80 "Video parts set" LNW80-2 $31.00

LNW80 Transformer LNW80-3 $18.00

LNW80 Keyboard cable LNW80-4 $16.00

40 Pin computer to expansion cable $15.00

System Expansion Transformer $19.00

Floppy Controller (FD1771) and HART (TR1602) . . . $30.00

VISA & MASTER CHARGE ORDERS&INFO. NO. 714-552-8946 ACCEPTED Add $3.00 for shipping SERVICE Na 714-641-8850

Circle 219 on Inquiry card.

Listing 2 continued:

21300

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EXCEPTION

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Listing 2 continued on page 354

352 May 1981 © BYTE Publications Inc

4008 (8K RAM - 40 Column) $ 795

16K"B"(16K RAM-40 Column) 995

32K "B"(32K RAM - 40 Column) 995

32K "N" (32K RAM - 40 Column) 1295

4032 "B" (32K RAM 4.0 Basic - 40 Column) .... 1295

4032 "N"(32K RAM 4.0 Basic - 40 Column) .... 1295

4016 "B" (16K RAM 4.0 Basic - 40 Column) .... 995

4016 "N" (16K RAM 4.0 Basic - 40 Column).... 995

2022 Tractor Printer 795

4040 Dual Disk (340 2.0 DOS) 1295

8050 Dual Disk (1 Meg, 2.0 DOS) 1795

8010 IEEE Modem 395

CZN Cassette , 95

PET - IEEE Cable 40

IEEE-IEEE Cable 50

Why not buy from the best ?

INTERTEC DATA SYSTEMS

32K Superbrain

(360K Disk Storage), CP/M* $2995

64K Superbrain

(360 Disk Storage), CP/M* 3150

64K Quad Density Superbrain

(700K Disk Storage), CP/M* 3995

ATARI ^ COMPUTER A< SYSTEMS .-j55?L«

ATARI 400 (8K RAM) $499.00

ATARI 400 06K RAM) 630.00

ATARI 800 (16K RAM) 1,080.00

ATARI 410 RECORDER 89.95

ATARI 810 DISK DRIVE 599.95

NEECO also carries all available ATARI software

ALTOS COMPUTER SYSTEMS

RAM DISK

ACS 8000-IS 64K 250K $2840

ACS 8000-28 64K 500K 3500

ACS 8000-1 64K 500K 3840

ACS 8000-2 64K 1M 4500

ACS 8000-4 64K 2M 5600

ACS 8000-5 64K 1M 5990

ACS 8000-6 Mul2 - Multi-User

(14.5 M-Wlnchester) 112K 1M 10,670

(29 M-Winchester) 112K 1M 11,870 ACS 8000-6 Mul4 Multi-User

(14.5 M-Winchester) 208K 1M 11,960

(29 M Winchester) Wm 1M 1^160

lappkzGomputGr

^ AiSthSrized Dealer

16K APPLE 11+ $1330

32K"II+ 1430

^ 48K " 11+ 1530

APPLE DISK

w/3.3 DOS 650

APPLE DRIVE Only 495

APPLE III in Stock!!

128K, with Monitor and Info Analystpak 4740

EPSON PRINTER MX-80

80 Columns, 9x9 Dot Matrix Bidirectional Printing .. $645 Interface Cards

8140 (RS-232) $55

8161 (IEEE 488) 55

8131 (Apple Card) 85

8230 (Apple Cable) 25

8220 (TRS-80 Cable) 35

PROFESSIONAL SOFTWARE

WordPro I (8K)... $29.95 WordPro III

(40Col.)16K 199.95

WordPro 111+ Enhanced

Version 295.00

WordPro IV

80 Col., 32K 375.00

WordPro IV+ Enhanced

Version 450.00

Multi-Cluster for Commodore Systems.

Allows 3 CPU's (Expandable to 8) to access a single Commodore Disk.

Multi-Cluster $795 (3 CPU's)

Each Additional CPU $199 (up to 8)

DIABLO 630

45 CPS, Letter Quality

RS-232 Port $2,710

Tractor Option 250

NEC Spjnwriter

5530 (Parallel) $3055

5510 (Serial) 3055

5520 (KSR-Serial) 3415

TRACTOR OPTION ... 225

55 CPS Letter Quality High Reliability

C. ITOH Starwriter

Serial or Parallel $1995

FP 1500 25 CPs, Letter Quality

MppOn NEECO Order Lines: (617)449-1760

MON - FRI 9:00-5:00 VISA/MC Accepted Telex 951021

NeldL'at MA;Tm NEECO Order Lines: (617) 449-1760

MON - FRI 9:00-5:00 VISA/MC Accepted Telex 951021

Circle 282 on Inquiry card.

BYTE May 1981 353

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0 3l)K

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B8

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ADC A

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EXCEPTION

Listing 2 continued on page 356

354 May 1981 © BYTE Publkatigns Inc

NEW LOCATION

1198 E. Willow Street Signal Hill, CA 90806

Toll Free (800) 421-7701 Outside Calif.

(213)595-6431 msidecaiii.

MICROBYTE S-100 BOARDS

• A compleie airiQla boaiil ZBOa C^U wiin seiiaUpariiiDi interlace •Fully compallblo with ine pioposBd IEEE S-100 Bus Standard - "A CPU MMH7 vorsion o1 trio2.30)

ORDERING INFO

TERMS

Name, address, phone Ship By: UPS or Mail Shipping Chrg. Add $2.50 up to

2 lbs. (UPS Blue) U.S. Mall Add $1.50 (U.S. Only) ($25.00 Minimum Ordei)

We Accept Cash, Check, Money Orders, Visa & Master Charge (U.S. Funds Only) Tax: 6% Calil. Res. COD'S a Terms Available on Approval (School PO's Accepted)

M5a rr

Z-80A/I-O S349.00 Assembled & Tested Optional MonJtor Program $50.00

-Full vecio'oa inieffupl upabDIty —

H D.l MNI(1 bit)

• 3MHz 01 4MH( opBrailen li jumpe<

tor B<lending Ml", MBEO* IORQ° anaiO' on DoaiQ ROM

• Dual RS 232 serial I'O pom usms ma zaOA-DART witn mdi»<duai DBud rata Hltctton (tiom 50-19,200 baudi

•Up t<i Z* W paralW 1(0 port-tulty piogrammabit Iniai BIS9A

Disc Controller $389.00

Assembled & Tested

CPM Available (Opiional)

MICROBYTE

•DMA lo wiiltin IBM byre ol mama•SiBia-ol-tne-aft NEC705 LSI

Controller

•lEEE-SiOO Compal'Die • DMA arcitialton allows use ol muiirpiB Boatdi wilh.n a sysiem •PLL dala recQvpFy to> Inlallv feliaW

aiandaid dfives

•Sepataie wcc •upo'y

64K RAM Board Assembled & Tested Call for Price

MICROBYTE

•Fuly S100 bus compslihle •E4K X S bii dynamic RAM

■Low power

-t- avOC m 700 ma

♦ 16V0C <!i 100 ma

- 16VDC *i 25 ma •Buill-ln panly wiin LED indicaloi

•Memory addressable m (our IBK

•Hidden refesh

•Gold coniactH lo' high reliabilliy • 72-hour Burn'in

•Memory mapped via DIP switch •Sul t in programmable wrile drolec •PiOfltammableconiroi po-i Inr niirii and bank control

INFLATION FIGHTER

4116'S (200 ns.) Apple, TRS-80, Heath 8 for $,22""

16- 49

50- 99 100-499 500 Up

$2.60 $2.50

$2.40

$2 25

2114 L-2/200 NS

i/O Board $289.00

Assembled & Tested

Cables Available (Optional}

MICROBYTE

•Quad RS'232C Serial Porta. One

20mA Cutrenl Loop Porl •Fully IEEE !i-100 Bus Compatible -Asvncnronous Cofflmunicaltons

wiih zaOA.DarnTMi of SynchKHious

Communicalions with ZSOA.

r.lO'(l;n,<i

Hi PoIip<i (2i Bus Vector i3i ZBO MoUe 2 Vector •Oil Board inipnuoi Daisy Chain

•Spectal Receive Condllions: 11) Framing Error; (2) pailly E'lor; (3) Receiver Overrun Error

>Baud Rates Seiecied Individually

Irorn 50 Baud lo 300K Baud

1-16 17-49

50-99 100-499

500 Up

$3.60 ea. $3.40 ea.

$3.25 ea. $3.00 ea.

$2.85 ea.

S.D. SYSTEM I S-100 BOARDS

EXPANDORAMI 16K $239.00

2MHz DYNAMIC 32K $265.00

RAM BOARD 48K $289.00

KITS 64K $315.00

EXPANDORAMII 16K $250.00

4MHz DYNAMIC 32K $275.00

RAM BOARD 48K $300.00

K\TS 64K $325.00

SBC-100KIT $299.00 2.5 MHz/Z-BO CPU WITH SERIAL & PARALLEL I/O PORTS

SBC-200 KIT $325.00 4MHZ/Z-80 CPU WITH SERIAL & PARALLEL I/O PORTS

VDB-8024 KIT $380.00 80x24 i;0 MAPPED VIDEO BOARD WITH KEYBOARD I/O

VERSAFLOPPY I KIT $250.00 DISK CONTROLLER FOR 8" & 5Va" DRIVES S-100 BUS COMPATIBLE

VERSAFLOPPY II KIT $350.00 NEW DOUBLE DENSITY DISK CONTROLLER FOR 8" & 5Vt" DRIVES

PROM-100 KIT $210.00 S—100/EPROM PROGRAMMER FOR 2708, 2716, 2732, 2758 & 2516(TI)

ALL BOARDS ARE AVAILABLE

(ASSEMBLED & TESTED) CALL FOR PRICE & DELIVERY

SYSTEM SOFTWARE AVAILABLE ON REQUEST

ATARI 800

(NEW 16K VERSION)

• COMPUTER CONSOLE •OPERATORS MANUAL

• ATARI BASIC 8K RAM -RF MODULATOR •57 FULL STROKE •POWER SUPPLY

ALPHANUMERIC KEYS * ADDED OPTIONS

PLUS 4 FUNCTION KEYS'JOYSTICKS •INVITATION TO PRO- 'EDUCATION ROM CRAMMING CASSETTE (NO CHARGE) CALL FOR PRICt 10" r. OFF SOFTWARE V.'ITH PURCHASE

ATARI OPTIONAL ACCESSORIES

MODEL* DESCRIPTION

PRICE

810

Disk Drive System

$ 499.00

815

Disk Drive System

$1199.00

820

40col- Del Matrix Printer

$ 349.00

822

40-col. Thermal Printer

$ 349.00

826

aO col. Dot Matrix Printer

$ 750.00

830

Acoustic Modem

$ 159.00

860

Interface Module

$ 175.00

CXB53

16K RAM Module

$ 140.00

410

Cassette Recorder

$ 60.00

CALIFORNIA COMPUTERS CAPACITORS

.1 @ 12 Volt Ceramic 84: ea. or

100/$7.00

32K STATIC RAM BHD. 64K DYNAMIC RAM BD.

16K STATIC RAM BD. MAINFRAME DISK CONTROLLER MOTHERBOARD 4-PORT SERIAL I/O 2 SEP. PORT & 2 PAR. 4-PORT PARALLEL I/O 6502 CPU BOARD Z-80 CPU BOARD 7114A 12K ROM/PROM BD. 7424A CALENDAR CLOCK BD. 7440A PROGRAMMABLE TIMER 7470 A/D CONVERTER 7710A SERIAL SYNCH. BOARD 7712A SERIAL SUNCH. BOARD 7720A PARALLEL INTERFACE 7728A CENTRONICS INTERFACE CALL FOR PRICE S, DELIVERY

2032 2065 2116 2200 2422 2501 2710 2718 2720 2802 2810

COMPONENTS

74LS240 1.25 ea,

74LS241 1.IOea.

74LS244 1.25 ea.

74LS373 1.25 ea.

74LS374 1.25 ea.

8T245 1.45 ea.

2708/450 NS

CONNECTORS

100 PIN IMSAl GOLD/S-100 SOLDERTAIL $2.40 ea. or

10/$2.25 ea.

$5.25 ea.

OR

8/$40.°°

2716/5 VOLT

$8.00 ea.

450 NS.

Major Manufacturer

QUME DT-8 DISK DRIVE

• Double-sided/Single-Double Density

• IBM-compatible/1.2 Mbytes/Disk

• Fast — 3 ms. Track to Track

• 154 Tracks/Daisy Chain 4 Drives

• ISO Standard Write Protect

• Programmable Door Lock CALL FOR PRICE & DELIVERY

ATARI SOFTWARE

Description Price

Basketball $30.00

Super Breakout $30.00

Chess $30.00

Video Easel $30.00

3-D Tic Tac Toe $30.00

Star Raiders $42.00

Music Composer $42.00 Educational Sys. ROM $19.95

Assembler/Editor $45.00

Telelink I $19.95

Space Invaders $15.95

Kingdom $12.95

Blackjack $12 95

Biorhythm $12.95

Graph it $15.95

Energy Czar $12.95

Mailing List $16.95

Statistics I $16.95

Paddle Controls $17.95

Joysticks (pair) $17.95

NOVATION CAT

300 BAUD, AUTO ANSWER/ACOUSTIC

$149.00 ea.

NOVATION D-CAT

300 BAUD/DIRECT CONNECT

3169.00 ea.

(OPTIONAL RS232 CABLE $22.00)

MONITORS

AMDEK 100 12" B&W $129.00 SANYO VM5012 12" B&W $260.00

AMDEK 13" Color $375.00 IN STOCK

LO-PRO MICROPROCESSORS SOCKETS

$ 2.50

Z80A $ 8.95

Z80ACTC $ 7.95

Z80A DART $13.95

Z80A SIO $24.95

8255 ACS $ 5.95

8257 AC5 $ 8.95

8224 $ 2.75

1-99

100 Up

14 PIN

.10

.09

16 PIN

.12

.11

18 PIN

.15

.13

20 PIN

.23

.21

24 PIN

.26

.24

28 PIN

.30

.28

40 PIN

.40

.38

(BURNDY/TIN SOLDERTAIL)

CENTRONICS 737-1 ANADEX DP8000 ANADEX DP9500 ANADEX DP9501 TEXAS INST 810 BASE 2 800 MST

CALL FOR PRICE & DELIVERY

REGULATORS

320T5 .. .80 340T5 .. .70 320T12 . .80 340T12 . .75

78L12 25

RS-232 CONNECTORS

DB25P DB25S 1-9 2.90 3.B0 10-24 2.75 3.70 25 Up 2.40 3.60 Data Phone Hood 1.00

Price Box of 10

$26.50

IDISKETTESI

Part If

MD525-01

Verbatim 5%" (soft)

Scotch 5V<" (soft)

744-0

$33.00

Scotch 5'A" (to-sec)

744-10

$33.00

Scotch 5 V<"{16-seo)

744-16

$33.00

Memorex 5%" (soft)

3421

$24.00

Scotch 8" DS (solt)

743-0

S49.95

Maxell8" DS;DD

FD-2D

$65.00

SHUGART SA 801R

8" Sgl.-Sided, Sgl./Dbl.

Density Disk Drive Call for Price Bt ElMiifBiy!

New 16K RAM

MODULE FOR ATARI 800 Computer Systems

$89.95 each

J YEAR WARRANTY

MAIN/FRAME & DISK DRIVE CABINETS from INTEGRAND

MODEL X5 — DBsktop Malntramo - 5 Cards - Small Power Supply $200

CaDinel size 9 4"w x I6"d x 7 5"ri Cabinet painted dove grey. Irani panel is black No optlonil cDlonI 5-position molheiboard. 5 conneciors installed, card cage with all guides Reset switcfi on troni panel Power switch. 4 0825 cutouts. 1 BNC mounling hale, 70CFU far. EUi liller, 6' power card, line luse, and clamped Ital cable exit on rear panel. PX/5 power supply (-fegilOA, -i-l6@l.5A, -16@1.5A) Power supply is a removable module.

MODEL 700D - Horizontal Dasktop Diik/Cov«r - 2 Eight Inch Drivai - Drtvci Horlzontii $250

Cabinei size: 20"w x 23"d x 7.y 'h. cabinet painted dove giey. tront panel is black. Mounting lor 2 eight-Inch Shugart SA8OIR Floppy DISK Drives (or mechanical flQuivaleni). Drive nwinllng brackels supplied. Drives not suppfled. 70CFM fan. 6' three-vrim Une cord, poiverswiicn, lirtehi», EMI filler and clamped HaicatMuH on rear panel. power supply •»504A. •«>24ig5A-6A peak. -5@,7SA. All vdiages regulated. Power supply is a removable module.

MODEL 800D - Desktop Main/Frama - IS Cirdi - Stindird Powor Supply SZ5S

Cabinet size I7' w x 20 5 "d > 7 &"h. Cabinet painted dove grey, Ironi panel is black (other color schemes Dpiional) l5 pos;iion IEEE compaiibie moinerDoardfwiliacbqilTeOI larminalor kil, optional), card cage wilh all guides Resel switch on Ifoni panel Power switch, 8'DE25 cutouls. 2 8NC mounting holes, 70CFM Ian, EMi liiier. 6' power cord, ime fuse, and clamped Hal cable exit on tear panel P800 powar supply {-^B@l5A. + 16@3A, -l6@3Ai Power supply is a removable module MotHerboarO connectors aplional

MODEL 700DS - Variical Dasktop Disk/Cover ~ 2 Eight Inch Drives - Drives Verticil $250

Cabinet size 13 5"w x 23"d k iV'h Cabme' painted dove grey, troni panel is black Mojniing lor 2 eight-inch Shuoart SAflOtR Floppy Disk Drives (or mechanical epi ivalenl). Drive mounimg brackets supplied Drives not supplied. 70CFM fan, 6' throe-wire line cord, power switch, line li'Se, EMI filler and clamped Hal caole ewi on rear panel. P794 power supply: ■f5@4A. -t-24@5A-6A peak, -5@.75A. V\ voilages regulated. Pov^er supply is a removable module

Circle 33 on inquiry card.

BYTE May 1981 355

Listing 2 continued:

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Listing 2 continued on page 358

356 May 1981 © BYTE Publications Inc

I\ID IT J5f\IT!!

mi ^rnaum

No this isn't a "Hard Disk". We used to call it that, sometimes. But somebody muddied the water.

"Hard Disk", unfortunately, now calls something else to mind. That little bitty guy with no backup capability and no way of switching media? It's a "Hard Disk" to work with, all right, in business applications. Some even say

"Impossible Disk".

We'd like to avoid confusion between our Cameo database solution and the one that doesn't work so well. The Cameo DC-500 subsystem employs a decade-proven cartridge disk. Our backup capability is built in, and takes four minutes. The ability to switch applications (by exchanging the removablie cartridge) means you can use your computer for more kinds of work. A ten megabyte (5 fixed + 5 removable) subsystem costs $5995, for your TRS-80* (Mod. I or II), Apple*, Heath H89^'' or S-100 computer. So call us "The Cartridge Disk Guys", please, and call us soon. We'll showyou the really cost-effective solution to microcomputer database storage.

AMEO ELECTRONICS INC.

1626 CLEMENTINE ANAHEIM, CA 92802 (714)535-1682

TRS-80 is a registered trademark of the Tandy Corp. 'Apple is a registered frademarl< of Apple Corp.

Circle 61 on Inquiry card.

BYTE May IMl 357

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COMPLEXION APPENDAGE ADDRESS

5R60U

ISNU

Choicre

GNT Makes a Tape Punch Station and a Tape Reader/Punch Combination.

Both are small, quiet, and economical. One of them will fit your needs exactly.

The 4601 Combo

• Punching speed: 75 Cps Reading speed: up to 150 Cps

• RS-232-G serial interface

• Utilizes all types of Mylar® and paper tape

• Reliability: MTBF100 million characters

The 3601 Punch

Puncliing speed: 50 or 75 Cps

• RS-232-C serial interface

• Utilizes all types of Mylar® and paper tape

• Reliability: MTBF 100 million

characters

Contact your local dealer or call for complete specifications. See us at NCC — Booth 3004

GNT AUTOMATIC INC

1560 Trapelo Road, Waltham, MA 02154 (617) 890-3305 Telex: 923318

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358 May 1981 © BYTE Publicatioiw Inc

Circle 333 on Inquiry card.

• The easiest-to-use full-feature CP/M word processor is priced lower than the rest.

Hundreds of dollars lower!

• Fastest-to-leam—basic features in one hour. Full capability in half a day of use.

No complicated symbolic commands!

• First with color-coded replacement keys— color and legends indicate function.

No menus cluttering the screen.

• Kmega-supplied keytops are the reference card. One hundred fifty-page manual is color-coded to the keys.

• Optional SpellRite—the first authorized, fully integrated version of Spellguard, a 10,000-word-per-minute proofreader.

APPLE II PRODUCTS

• Peachtree 40: we install, train and service Peachtree on the Apple in Northern California. Call for pricing.

• Tax Preparer: too late for 1980, but time

to automate your tax record-keeping for '81. Free schedule updates for '81 forms, when available from IRS. $150.

• Real Estate Analyzer: evaluate cash flow, ROI, depreciation, etc., to determine the value of a potential or existing investment. $150.

CP/M*= Digital Research, Spellguard*^ ISA, Peachtree 40=' RSI, VTS/80^ .NMP, Spell Rite™ Kmega, Tax Preparer and Real Estate Analyzer*^ Howardsoft

ORDER BLANK

□ Send me VTS/80 with SpellRite integrated: $590 including diskette, manuals, and custom replacement keytops for my system.

□ Send me VTS/80 alone: $295 including diskette, manual and custom replacement keytops for my terminal.

□ Send me Spellguard alone. I already own the word processor.

□ Send me

for my Apple II. The price is.

including diskette and manual. □ Send me a copy of your comparison of VTS/80, Word Star and Magic Wand.

My check for $ is enclosed. (California

residents add 6.5% tax.) Outside North America shipping is an additional $20.

Name

Street

City/State/Zip

Telephone

Computer

Terminal :

Printer

Contact us or your local computer dealer.

iKmgqg

Kmega Microsoftware • 1080-F East Duane Ave.

Sunnyvale, CA 94086 Telex 172246

(408) 730-9203

circle 211 on Inquiry card.

BYTE May 1981 359

Build a Super Simple Floppy-Disk Interface, Part 1

James Nicholson and Roger Camp 1046 Gaskill Ames lA 50010

For personal-computer users, a floppy-disk system represents the ultimate in mass storage because of its speed and capacity. The floppy-disk controller described in this article provides all the capabilities found in commercial systems, yet it is simple and economical because it requires only ten integrated circuits. Fundamental software will be provided (in the second part of this article) to control and perform data transfers, and discussion of file structuring and alternate hardware will give the experimenter ideas for improvements.

This system uses the FD400, an 8-inch floppy-disk drive manufactured by the Pertec Computer Corporation, and the popular Western Digital 1771 floppy-disk controller integrated circuit (which allows such special features as variable block size, soft sectoring, IBM compatibility, and much more). Although the specifics shown are for microcomputers based on the MOS Technology 6502 microprocessor, the controller could be adapted to other microprocessors with some care at a few crucial

About the Authors

Roger Camp is a Professor of Electrical Ertgineering at Iowa State University. He is the author of several technical papers and patents, and his most recent book is Micro-Processor Systems Engineering.

James Nicholson, currently Project Manager, Business Recovery Planning, has been involved in large data-center activities for Donnelley Marketing. He has designed and built several microcomputer systems in the last five years.

points. The 6502 offers some speed advantages and a programming ease not afforded by the others.

Fundamentals

The data recorded on floppy disks is logically arranged in concentric rings called tracks, with each track composed of blocks of data called sectors. The computer must be able to

Thfs controller is simple

and economical because it requires only ten integrated circuits.

tell where a sector begins, and there are two ways of doing this. Each sector can be distinguished by its position relative to holes punched in the disk (this is called hard sectoring), or it can be distinguished by special sequences of information recorded on

the disk (soft sectoring). In either case, the disl< has one hole that is used ds an index to signal the start of the first sector on all tracks.

The most common 8-inch floppydisk format provides for 77 tracks of 26 sectors each, with 128 bytes recorded in each sector. The address of each sector, in the form of a track number (0 through 76) and a sector number (1 through 26), is recorded on the disk at the start of the sector itself.

The disk drive has two motors; one that spins the disk at 360 rpm (revolutions per minute), and one that moves the head from track to track on command. Each drive also has a printedcircuit board to control both motors. The inputs and outputs of this circuit board (see figure 1) follow a standard set by Shugart Associates, manufacturer of one of the first popular floppy-disk drives.

A single pulse on either the STEPIN line or the STEP-OUT line moves the head one track toward the center of the disk (track 76) or toward the

Photo 1: The authors' wire-wrapped floppy-disk controller board.

360

May 1981 © BYTE Publications Inc

NEW! HISTOGRAPH (Boyd) A calendar-based histogram or bar-graph production system. Allows the user to enter numeric data that relates to a date, and reproduces that data as a high-resoluSon Mstogram.

09009. Apple II Disk. $29.95

NEW! DATA-GRAPH (Boyd) Aids in the preparation of graphs and charts. Numeric data can be entered into Data-Graph and used to create colorful one-, two-, or four-quadrant graphs. 09109. Apple U Disk. $49.95

NEW! DOUBLE PRECISION FLOATING POINT FOR

APPLESOFTTM (S-C Software) Extends the accuracy of the arithmetic available on the Apple from nine digits to a hill 21-digit precision on all functions in Applesoft compalitiefonnat. 09409, Apple jffM, $29.95

ORDER NOWl

Hayden Book Company, Inc.

50 Essex Street, RocheDe Parit, NJ 07662

Send me the software checked below. A check or money order is enclosed. 1 understand that Hayden pays shipping and handling costs and that I can return any disk or tape within 10 days if it Is defective or I am dissatisfied with it for any reason. Re^denfs (rfNJ and CA must add sales tax. Offer good In US only. Name of Individual ordering must be filled in.

□ 03403

□ 03604

□ 07004

□ 03404

□ 03804

□ 07009

□ 03408

□ 03904

D 07101

□ 03409

n 04804

□ 07103

□ 03410

□ 04909

□ 07301

□ 03414

□ 05103

□ 08609

□ 03440

□ 05108

□ 09009

□ 03444

□ 05303

□ 09109

□ 03484

□ 05308

□ 09409

□ 03504

□ 05903

□ 09704

Name

Address

City/State/Zip_

81-009

Hayden Performance Software

from gameroom fun to boardroom business!

NEW! OP-AMP DESIGN (Gabrielson) Provides the necessary values for your design and vOill suggest appropriate op-amp types. Includes a choice of six op-amps, and the program will then determine if your selection of an op-amp will be acceptable within your chosen parameteis. Can be updated to accommodate future op-amps. 09704, Apple n tape. $16.95

UNE & VARIABLE CROSS REFERENCE GENERATOR (Johnson) Provides a aoss-reference of line numbers and vaiiaUe names. 073O1, PET tape, $16.95

APPLESOFT UTILITY PROGRAMS (Gilder) Increase your BASIC programming speed and flexibility. Contains 9 useful subroutines: 1. REM Writer 2. PRINT Writer 3. POKE Writer 4. Hexadecimal/Decimal Converter 5 Line Counter 6. Renumber 7. Append 8. Byte Counter 9 Slow Ust/Stop List 03504, Apple 11 tape, $29.95

RENUMBER & APPEND: UUIIty Programs for the

Apple (Gilder) Renumber your Applesrat program and append a second program to the one in memoiv.

03804. Apple n tape. $14.95

REVIVE (Gilder) When a program is accidentally erased, REVIVE searches through memory and finds the information that enables it to restore the pointers that have been changed. 03604. Apple II tape. $19.95

SLOW LIST/STOP LIST: Utility Programs for the Apple (Gilder) Start, stop, and controlthe speed of your program with Apple ll's game paddles. 03904, Apple II tape. $10.95

PSEUDODISK (Neuschatz) This money-saving program simulates a disk memory system for Integer BASIC programs. It allows multiple programs in memory at the same time which can-be run from a catalog. 04804, APPLE n tape, $24.95

6502 DISASSEMBLER (Stamm) Produce assembly

language source files with labeled subroutines and references from programs already in memory. It is compatible with Hayden's ASSEMBLY LANGUAGE DEVELOPMENT SYSTEM. 08609, APPLE B Disk, $39.95

DATA MANAGER: A Data Base Management System and Mailing List (Lutus) Store information on a floppy disk, and retrieve it quickly and easily by specific names, or by category. 04909, Apple II Disk Vernon. $49.95.

Apple is a trademark of Apple Computer Company. Inc., and is not affiliated with Hayden Book Company, Inc.

FINPLAN: A Financial Planning Program for Small Businesses (Montgomery) Allows you to enter

data from a balance sheet into the program, to make assumptions about the future growth of business, and to have the computer project results for up to a five year period based on those assumptions. And if you change any data, the program revises all resulting data automatically. The disk version can be used only with TRSDOS Version 2.3. 05103, TRS-SO Level B tape, $69.95: 05108. TRS-80 LevelB Disk Version, $74.95

SARGON 11 (Spracklen) The Champ of champs, "...an excellent program which will provide a true challenge for many players.. .Save your money and buy SARGON II..." W Software Critque. 03403. TRS-80 LevelII; 03404. Apple II: 03410. OSICIP: 03440. OSI C4P: each tape $29.95. 03408. TRS-80 Level II Disk: 034O9, Apple B Disks 03414, OSI CIP Disk; 03444, OSI C4PDisk 03484, CSPDisk; each $34.95

BLACKJACK MASTER: A SImulator/Tutor/Game

(Wteaney) A serious game that performs complex simulations and evaluations of playing and betting strategies. 05303. TRS-80 Level U tape. $24.95; 05308. TRS-80 Disk Version. $29.95

REVERSAL (Spracklen) Winner of the software division

of the First hternatior^al Man-Machine OTHELLQTM Tournament, this version of the 200-year old game Reversi, features 27 levels of play and high-resolution color graphks. 07004, APPLE B tape, $29.95; 07009, APPLES Disk, $34.95

ROYAL FLUSH: Competitive Poker Solitaire

(Wazaney) A game you can play alone or with any number of players. High score wins in this poker-based, fun-filled card game. Choose from possible game variations. 07J01, PET; 07103, TRS-80 Level B, each tape, $14.95

STARCLASH (VMon) An exciting game of galactic strategy for one or two players. 05903. TRS-80 Level B tape, $16.95

SOFTMCARE

Available at your local computer store!

50 Essex Street, Rochelle Park, NJ 07662 Book Company, Inc.

Circle 176 on Inquiry card.

BYTE May 1981 361

circle 231 on Inquiry card.

Systems, Inc?l

(203) 342-2747

NORTH STAR HORIZON:

KRZ-2-32K-D-FactorY ASM$2275 HRZ-2-32K-Q-Factory ASM$2675 64K DD or Q Also Available

HDS-18-F $4449

Northword DQ $ 359

INPO-Manager...., S 365

Mail Manager ,...$ 269

General Leger $ 775

ACC. REC. OR ACC.'PAY..$ 445

Word Star $ 350

Medical-Dental SYS.....$2500

COMMODORE (PET):

2001-32K-BorN Keyboard $1090 16K Also in Stock....$8S9!!! 8032 (80 Column Screen)$1599 2040 Dual Floppy Drive $1090 8050 Dual Floppy (1MEG)$1599 2022 Tractor Printer...$ 749

• Word PRO IV $ 290

VISICALC $ 195

APPLE II PLUS Call For Price!

ATARI 800 , $ 849

TI 99/4 Console&Monitor.. $990

INTERTEC SUPERBRAIN:

32K RAM $2595

64K RAM $2695

PRINTERS

Letter Quality:

NEC 5510 or 5530 $2550

NEC 5520 KSR $2950

DIABLO 630 $2390

C. ITOH $1690

Dot Matrix:

CENTRONICS 730 $ 599

" " 737-1 $ 799

" " 799 $999

EPSON MX-80 $ 599

PAPER TIGER 460G $1250

BASE II MST $ 649

DISPLAY TERMINALS

HAZELTINE 1420 $ 949

" " 1500 $ 999

INTERTUBE III $ 775

TELEVIDEO 920C $ 849

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. (203)342-2747 TWX 710-428-6345 L M-F 9-6 SAT.9:30-3:00 ^

TRACK-0

DOOR-OPEN

INDEX-PULSE

PERTEC F D 400 8-inch

r LUfr T uioi\ DRIVE

WRITE-PROTECT

READ-DATA

TRIM-ERASE

WRITE-ENABLE

WRITE-DATA

HEAD-CURRENT SWITCH

DRIVE-MOTOR-ON

HEAD-LOAD

STEP-IN

STEP-OUT

Figure 1: Input and output lines available for controlling a Pertec FD400 8-inch floppydisk drive. These signals are the same as those found on any Shugart-compatible drive,

so nearly any drive may be substituted for the FD400.

outside (track 0), respectively. When the head is positior\ed over track 0, the outermost track, the TRACK-0 output is activated. To turn on the spindle motor, the DRIVE-ON input must be activated, and the disk door in the front of the drive must be closed (this deactivates the DOOROPEN output line). As the disk rotates, a photoelectric sensor in the drive detects the index hole in the disk; this generates the INDEX signal that allows the system to begin counting sectors at the first one.

To read data, the HEAD-LOAD line is activated to force the head to contact the rotating disk surface. A mixture of data and clock bits are then detected and amplified by the drive's electronics; these appear as logic levels on the DATA-READ output at the rate of 250 K-bits per second.

To write data on the disk, the head must be loaded, the WRITE-ENABLE line must be activated, and the data inust be sent to the drive on the WRITE-DATA line. (This must occur with very specific timing.) If the WRITE-PROTECT output has been activated, the drive has detected the presence of a write-protect notch in the disk's envelope.

Obviously, communication at this level between a disk drive and a microcomputer is possible but not desirable. The microcomputer would spend much of its time catering to the needs of the disk rather than computing. The purpose of the FD1771 (actually a microprocessor in its own right) is to act as a high-level com

munications interface between the two.

When instructed to seek (move the head) to track 30, the 1771 will generate the appropriate number of STEPIN or STEP-OUT pulses to move the head from its current position, wherever it may be, to track 30. Another example of the 1771's capabilities is the process of reading a specific sector: the 1771 will search a given track for the proper sector address; when located, the data following the address is transferred to the microprocessor. Simultaneously, the 1771 can maintain synchronization with the disk drive and check for errors. Therefore, using the 1771 floppy-disk controller circuit results in a greatly simplified hardware and software design.

Software must be an integral part of the design of any computer subsystem—a subroutine of about 256 bytes is required to communicate the proper commands to the disk controller. Additional software is required to handle complex data-file structures (this software and various structuring techniques will be discussed in part 2 of this article).

Disk Format

Figure 2 schematically describes the format of recorded data on a soft-sectored disk. The pulse generated by the index hole passing the sensor provides a physical reference point to determine the beginning and the end of a track. The diagram represents 16 256-byte sectors (the authors' choice for format) rather than the usual 26

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Circle 12 on Inquiry card.

BYTE May 19S1 363

sectors containing 128 bytes.

The disk rotates once every 166.67 ms, which allows the drive to

read 41,665 bits of information; that is, a byte every 32 iis. Each track contains 5208 bytes (divided into data and control bytes), as well as gaps between sectors. (The gaps are required to allow sufficient time to turn writehead current on and off without destroying valid data.)

The JAM (index-address mark) that provides a recorded indication of the beginning of the track has 16 sectors recorded after it. The sectors consist of two records: the ID (identification record) and the DATA (data record). The ID contains information on the track number and the sector number of the DATA that follows. Each of the records begins with an AM (address mark). In addition, each record is ended with a 2-byte CRC (cyclicredundancy-check) code.

Each byte of data recorded on the disk consists of interleaved clock and

data bits. The clock bits convey information used for synchronization and for the identification of AMs. AMs always have clock bits corresponding to hexadecimal C7 (D7 in the case of the lAM); all other bytes of information have clock bits corresponding to hexadecimal FF. In other words, some clock bits are omitted in AMs. This scheme allows the data bits of a dataaddress mark (hexadecimal FB) to be distinguished from a hexadecimal FB recorded as data.

Figure 2 also illustrates that these data and clock bits are recorded as a single stream. When reading from the disk, the 1771 separates the data and clock bits (although our system uses discrete components to achieve greater reliability).

As a general rule, the larger the sector, the greater the total amount of data that can be recorded on one disk. This is due to the reduced amount of area necessary for gaps and indexing informatibn. Usir\g 16

256-byte sectors, 315,392 bytes of data can be recorded. The usual configuration of 256-byte sectors allows tracks with only 15 sectors; however, it has been found that sufficient space is available to reliably record 16 sectors.

Western Digital's 1771 FloppyDisk Controller

This device is essentially a microprocessor dedicated to the specific task of controlling disk drives (see figure 3). It has five programmable registers and accepts a number of commands through various combinations of them. For economic reasons, there is a desire to connect multiple drives to a single 1771, but, since the device "remembers" the track the head was last positioned to, switching from one drive to another would place an added burden on the driving software. A case can be made for complete duplication of the controller electronics for each disk drive.

INDEX HOLE

lAM

SECTOR 1

SECTOR 2

SECTOR 16

11

lAM

1n /ADDRESS > ' " (RECORD '

I

DATA

RECORD ' — 1

7 BYTES

I AM

AM

TRACK

SECTOR

SECTOR

CRC

CRC

NUMBER

0

NUMBER

LENGTH

1

2

cLocKjijLjouirLD^^jinjijmiwLFF DATA _[injuuui_ Fc , n nn_ «

1 BYTE

256 BYTES

2 BYTES

AM

DATA

CRC 1

CRC 2

_rinnjui_rin_"

/ji_jmji_JLJi_JLJiruui>

0 1 0 0 0 oil

Figure 2: The format of recorded data on one track of a soft^sectored floppy-disk drive. The lAM (index-address mark) marks the beginning of each track. See the text for details.

364 May 1981 © BYTE Publications Inc

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Standard features include lower case support, serial and parallel printer drivers, and an addressable cursor. MAPPER I is supplied with complete utilities including a memory test, a disk lest, a copy program, and a proprietary progr am for converting TRS-DOS files to CP/M files. $199.

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FOREIGN ORDERS must include full payment in US funds plus $25 for air shipping and handling.

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•CP/M is a TM of Digital Research. TKS-80 is a TM of Tandy Corporation.

circle 298 on Inquiry card.

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BYTE May 1981 365

The registers in the 1771 that can be programmed by the user are the data, track, sector, and command registers—there is also a status register that can be read from but not written to. These 8-bit registers form the basis for software control of any disk drive:

• Data register: In disk-reading operations, this register receives 8 bits of data in parallel from the disk via the shift register. The data is held until the computer can accept it, allowing the shift register to be ready for the next byte. During disk-writing

operations, 8 bits of data are transferred in parallel from the computer to this register and held until they can be accepted by the shift register for transfer to the disk. When executing the seek command, the data register holds the address of the desired track. •Track register: This register holds the track number of the current head position. The value is incremented by one for every track the head is stepped in (toward track 76), and decremented by one for every track the head is stepped out (toward track 0). The contents of the register are compared with the track number recorded

DATA OUT BUFFERS

DATA

REG

COMMAND REG

WRITE

DATA

(TO DISKI

DATA

SHIFT

REG

REG

AM

DETECTOR

CRC LOGIC

DATA SEPARATOR

in the ID field of sectors on the disk.

• Sector register: During read or write operations, the contents of this

8-bit register are compared with the sector number recorded in the ID field of sectors on the disk. The contents should not be changed while the device is busy.

• Command register: This register holds the command currently being executed. The register should not be loaded while the 1771 is busy unless the current command is to be overridden (this action causes an interrupt to be generated). The eleven commands understood by the 1771 are divided into four types, shown in table 1, according to the way their flag bits are defined.

• Status register: Information about the status of the controller can be read from this register. The meaning of the status bits may change depending on the current command.

Registers are accessed by placing

the proper logic levels on the AO, Al, RE, and WE lines, as shown in table 2. Other logic levels in the 1771 perform functions to:

;° • Generate and check the 16-bit CRC

code

• Increment, decrement, and compare register values •Detect ID, data, and index-address

marks

• Provide control signals based on an external 2.0 MHz clock

A typical disk operation includes the following steps. First, the soft

REG

FD CLOCK

XTDS

ORG

INTRO

CS

RE

WE

AO

Al

CLK(2MHz)

COMPUTER INTERFACE CONTROL

CONTROL

PLA

CONTROL (190 X16)

CONTROL

DISK

INTERFACE CONTROL

WG

TG43

.WPRT

. WF

. TROO

PHI/STEP .

PHZ/DIRC .

, DINT

HLD

HLT

WE

CS RE AQ

Al

DAL 0 DAL 1 DAL 2 DAL 3 DAL » DAL 6 DAL 6 DAL 7 PHI/STEP PH2/DIR PH3 3PM MR

(GND)Vss

[ 1

*0

Vdd (+12V)

]

[ 2

39

]

INTRQ

[ 3

38

]

DRQ

[ 4

37

]

DINT

[ 5

36

]

WPRT

[ 6

35

]

iP

[ 7

34

]

TROO

[ 8

33

]

WF

[ 9

32

]

READY

[ 10

[ n

□

31 30

] ]

WD WG

[ 12

29

]

TG43

[ 13

28

1

HLD

[ 14

27

]

FDOATA

[ 15

26

1

FDCLK

[ 16

25

]

XTDS

[ 17

2*

]

CLK

[ 18

23

]

HLT

[ 19

22

1

TEST

[ ?o

21

]

VCC(+5V)

Figure 3: Internal architecture and pinout diagram of the Western Digital FD1771 floppy-disk controller. The four programmable registers and eleven commands of the 1771 allow any microprocessor to control a disk subsystem using high-level instructions, thus removing a sigriificant burden from the disk-driving software. See table 1 for a summary of the commands.

366

May 1981 © BYTE PubUcaUom Inc

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Micro-Telegram performs all the functions of a Teletype machine, which means you and your Apple can access every single Western Union service, worldwide. Send mailgrams. Send and receive TWX® Telex,® and international cables. Receive Infomaster® up-to-theminute news, stock, foreign exchange, gold, futures, sports, and sM reports. Use your Apple to wire money. To send flowers. To check the snow at Sun Valley. To see what the Yen is selling for. To contact over 900,000 TWX and Telex subscribers around the world.

But unlike the Teletype machine, Micro-Telegram permits editing right on the screen, sends messages automatically without f—^

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Apple and Apple n are tmdemarks of Apple Gompucer. Inc. Western Union, Infomaster, TWX, Telexland Teletype are trademarks of Western Union, Inc.

Circle 441 on inquiry card.

BYTE May 1981 367

TYPE

III III IV

COMMAND Restore Seek Step Step In Step Out Read Command Write Command Read Address Read Track Write Track Force Interrupt

BIT VALUES FOR TYPE 1

h = Head Load flag (Bit 3) h = 1, Load head at beginning h = 0, Do not load head at beginning

V = Verify flag (Bit 2)

V = 1, Verify on last track

V = 0, No verify

rirn - Stepping motor rate (Bits 1 through 0) r, ro = 11 gives 40 ms step time

u = Update flag (Bit 4) u = 1, update track register u = 0, No update

(b)

(a)

BITS

7

6

5

4

3

2

1

0

0

0

0

0

h

V

r^

rg

0

0

0

1 ■

h

V

r.

ro

0

0

1

u

h

V

r,

u

0

0

u

h

V

r,

0

1

1

u

h

V

ro

0

0

m

b

E

0

0

0

1

m

b

E

ai

ao

1

0

0

0

1

0

0

1

1

0

0

1

0

s

1

1

1

0

1

0

0

1

0

1

Is

h

ll

lo

BIT VALUES FOR TYPE II

m = Multiple Record flag (Bit 4)

m = 0, Single record

m = 1, Multiple records b = Block length flag (Bit 3)

b = 1, IBM format (128 to 1024 bytes)

b = 0, Non-IBM format (16 to 4096 bytes) aian = Data Address Mark (Bits 1 through 0)

a^ao = 00, FB (Data Mark)

a,ao = 01, FA (User defined)

a^ao = 10. F9 (User defined)

a^ao = 11, F8 (Deleted Data Mark)

(c)

mj VALUES FOR TYPE III s = Synchronize (lag (Bit 0) J] = 0, Synchronize to Address Mark s = 1, Do not synchronize to Address Mark

(d)

BIT VALUES FOR TYPE IV

In thru I3 = Interrupt Condition flags (Bits 3 through 0)

10 = 1, Not Ready to Ready transition

11 = 1, Ready to Not Ready transition

12 = 1, Index pulse

13 = 1, Immediate interrupt

E = Enable HLD and 10 ms Delay E = 1, Enable HLD, HLT and 10 ms delay E = 0, Head Is assumed engaged and there is no 10 ms delay

(e)

Table 1: The high-level instructions of the FDl 771 disk formatter/controller device. When one of the instructions defined by table la is loaded into the command register of the FD1771, the FD1771 executes one or a series of actions. Bits represented by a letter within a command are defined in the bit-value tables for that type of instruction, fables lb through le.

ware coordinating the disk operation

checks to see if the controller is busy from the last command. If it is not, the software writes the desired command into the command register. If data is to be transferred as each byte is assembled (or disassembled) by the shift register, the controller sends a DRQ {data request) signal. When the

operation is completed, the controller

sends an INTRQ (interrupt request) signal. The status register can then be checked by the controlling software for seek, write protect, busy, or CRC errors.

Controller Hardware The schematic diagram for the

floppy-disk controller is given in

figure 4. In addition to the 1771 and the 6520 PIA (peripheral interface adapter), circuitry is included for read/write control, clock and data bit separation; head loading, and inversion of various signals as required by the FD400 disk drive.

Three gates convert the DIR (direction) and STEP signals from the 1771 into the STEP-IN and STEP-OUT signals needed by the FD400 disk drive. The HEAD-LOAD signal is conditioned by a simple one-shot (monostable multivibrator) and an inverter; this guarantees a fixed 40 ms pause allowing the head to load and settle. Once the interval has passed, a signal is sent to the 1771 to acknowledge the fact.

The data-separator and clock circuit was designed by Steve Christiansen of Iowa State University. This circuit contains four of the ten integrated circuits in the system. (If the disk drive yOu intend to use has sepa

AI

AO

0

0

0

1

1

0

1

1

Register Affected During Register Affected During

Read (RE = 0, WE = 1) Write (RE = 1, WE = 0)

Status Register Command Register

Track Register Track Register

Sector Register Sector Register

Data Register Data Register

Table 2: Access to registers within the Western Digital FD1771 disk formatter/controller device. The FDI771 has five internal registers: command, data, sector, status, and track. A given register is read or written by placina the approyriate values on lines Al and AO and pullim down either the READ-ENABLE (RE) line for a read operation, or the WRITE-ENABLE (WE) line for a write operation. The sector and track registers specify the sector and track when these parameters are needed by a given command byte. The command register, when filled, causes one of eleven highlevel instructions to be executed (see table 1). Data passes between the computer and the disk drive through the data register. After a command has been executed by the FD1771, the status register must be read before another command can be executed.

360 May 1981 © BYTE Publlotioni Inc

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United States

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RiA;M. addressing to 128 megabytes on a Z8000-2 system

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CP/FV1 is a trademark of Digital Research • CDOS is a trademark of Cromemco, Inc. • UNIX is a trademark of Belt LatX)rator)es F^SF SHIVA", VIRTUAL-PERSONALITY", and OMEGA RESEARCH" are trademarks of OMEGA RESEARCH". Mmm

P.O. Box 479, Linden, Ca. 95236 (209) 334-6666

9 am to 5 pm Mon. - FrI.

Circle 297 on inquiry card.

BYTE May 1981 369

+SV A

22 23 24 21 25 33 32 31 30 29 28 27 26 34 36 37

CSl

CS2

CS3

R/W

*2

DO

Dl

D2

03

D4

D5

D6

07

RES

RSO

RSI

PAO PAl PA 2 PA3 PA 4 PAS PA 6 PA7 PB7

IC6 6520

CA2 PBS

PB6

PB3

PB2 PBl

17 INTRO

4.7K

10

11 12 13 14

39

READ/WRITE LOGIC

13

15 READ

16 PRO

CLR

IC4b

° 7474

Q

CLOCK

13 RESET

19

12 Al

11 AO

Figure 4a: Schematic diagram of the computer-interface side of the floppy-disk controller. The 6520 PIA

(peripheral interface adapter) LSI (large-scale integration) device simplifies the circuitry so that only ten integrated circuits are needed for the complete controller system. The additional logic devices are used to provide the read and write signals expected by the 1771. See figure 4b on page 372 for the rest of the diagram.

Number

Type

+ 5 V

GND

IC1

7404

14

7

IC2

7400

14

7

IC3

74123

16

8

IC4

7474

14

7

ICS

7404

14

7

IC6

6520

20

1

IC7

FD1771

21

20

iC8

74193

16

8

IC9

74193

16

8

IC10

7402

14

7

-5V +12V

40

DALO DALl

6al2

DAL3

DAL 4 DAL5 DAL6 DAL7 INTRO

!C7

FD1771

RE

WE DRO

MR

Al AO

XTDS

rated clock and data signals, you may be able to eliminate some of the circuitry shown. Remember that the 1771 requires a 2.0 MHz clock.)

The clock part of this circuit is a conventional TTL (transistor-transistor logic) crystal oscillator which also drives a divide-by-two stage to produce the 2.0 MHz clock signal. The data-separator part of the circuit inverts the raw signal from the disk drive and gates it out as data or clock information, depending on the state

of the QD output of 1C9.

There is a certain difficulty in determining, from a serial-bit stream, which bits are clock and which data (the two are interleaved, and some of the clock bits may be missing). The solution relies on the fact that, at most, three clock pulses will be omitted; if four in a row are omitted, the data and clock outputs are switched by the external data-separator circuit.

The read/write circuitry is very compact and plays a major role in the

simplicity of the system. It is a subtle solution to a timing problem; the obvious approach of using the outputs of the 6520 to control RE and WE (the read- and write-enable lines) as input for the DRQ (data-request line) is too slow. The indicated circuitry using the ENABLE line causes each DRQ

signal to automatically generate

another RE or WE signal as required.

The 6520 has 20 programmable I/O (input/output) pins (see figure 5),

370

May 1981 © BYTE Publications Inc

Circle 164 on Inquiry card.

Circle 193 on inquiry card.

Complete AIM 65 Expansion

For complete AIM 65 expansion, Forethought Products brings you the AIMMate Series, quality expansion products with price, performance and versatility that puts them in a class of their own.

AIM-Mate Series expansion, including RAM (to 48K), PROM, I/O, video and floppy disk interface, STD BUS interface, parity protection and more, lets you configure the kind of system you need.

The compact AIM-Mate case puts It all together in a sturdy, portable, desk top unit.

Write today for complete details on the AIM-Mate System- AIM 65 expansion products for the professional.

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FREE Catalog

New 4-way relief from problems with Computer/WP supplies and accessories.

1. One-stop shopping.

I nmac (formerly known as Minicomputer Accessories Corporation) has a catalog of overlOOO products.Everything from racks and lineprinter paper to connectors and cables. Eacti designed to help keep your minicomputer or word processing system up and running.

2. Hassle-free ordering, inmac lets you order by

mail or phone. So l<eep thiis free catalog close. It makes those once-tough tasks like ordering your magnetic media easy fast and foolproof.

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c 1979 International Minicomputer Accessories Corporation

NOW

Eight memory slots for your Atari 800! Tlie AXLON 256 MEMORY SYSTEM has the capability to banl<-seieot up to 256K of online RAM memory The system is designed to accept Axlon's 32K RAMCRAMS, Atari's RAM modules, or a combination of the two. Our memory system comes complete v\/ith hardware, 64K of RAM, memory management softw/are, interface card and cable. Drop by your local computer store or contact Axion for more information.

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Memory management software included

Accepts Axlon 32K RAMCRAMS, Atari RAM modules, or a combination of both Dedicated power supply 90 Day Warranty

* indicates trademarks of Atari, Inc.

Circle 42 on Inquiry card.

BYTE May 1981 371

IC7

FD1771

FD CLOCK

FD DATA

IP

READY WRPT

35

32

36

TRKOO

34

W6 WD T643

DIR STEP

30

29

16

HLD

HLT

28

UP

DN

IC9

LD

74123

CY

CLR

QD B D A

C

11

11

12

S

14

- 14

OC

LD

ICS

DN

74193

UP

CLR

B

D A

C

+ 5V

:47K

+ 5V

H5V

I

4.7K TYPICAL FOR 3

19

ICl 7404

10

J

IS

11

Q

B C

40^S

IC3a

74123

RC

A

14

IC2 I 1^7400 J

16

ICl 7404

18

120K

-wv—

FD400 DISK DRIVE

WRITE-BUSY

INDEX

READ-DATA

DOOR-OPEN WRITE-PROTECT TRACK-0

WRITE-EN ABLE WRITE-DATA HEAD-CURRENT

STEP-OUT

STEP-IN

HEAD-LOAD DRIVE-OH

Figure 4b: Schematic diagram of the drive-interface side of the floppy-disk controller. Clock signals and minor control functions are provided for by the additional circuitry, as well as the separation of recorded data from recorded synchronization pulses.

of which only 17 are used in this system to interface with the 1771. The A

port is programmed as eight bidirectional data lines, and is connected to

the 1771's data lines, while the B port pins are programmed as necessary to

provide contro] lines. The data lines of the 6520 can be connected to like

lines on the microprocessor, while its three device-select lines can be connected to match whatever addressdecoding scheme is appropriate. The

372 May 1981 © BYTE PublicaHons liic

Circle 412 on Inquiry card.

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Pterm also works with acoustical couplers and other modems interfaced to the PET with the TNW-2000 or TNW-232D, Electronic mail and TWX Terminal programs also available. All units are addressable IEEE-488 devices, complete witli power supply cabinet, full documentation and one year warranty.

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1001

THINGS TO DO WITH YOUR PERSONAL COMPUTER

BY MARK SAWUSCH

333 pages

$7.95

333 pages, written in simple terms, of "what-to-do" and "how-to-do-it" Suitable not only for microcomputers, but for programmable calculators as well. Includes program listings, formulas, a glossary of computer terms and more! Definitely a MUST BUY!

A PARTIAL LIST OF APPLICATIONS

Electric Memorandum Energy Efficiency Computation

Test Your Typing Speed Statistical Analysis Options Analysis Logic Circuit Analysis Antenna Design

Carpenter and Meclianic's Helper

Income Tax Speed Reading ChecIt Digit Generator Personality Test Morse Code

Finances and Investments Biorythm Letter Writing

Calculation of the Number of Days Between Two Dates

Simultaneous Equation Solver Real Estate Evaluation Astrology

General Purpose Clock/Timer Recipe Index/Calculator RPN Calculator Amateur Radio

Computer Assisted Instruction Robotwar

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MOST ORDERS SHIPPED WmilN ONE BUSINESS DAY

Products damaged in transit will l>r (.'xcnangetj

PRICES IN EFFECT May 1. 1981 THRU

May 31. 1981. Prices, Specifications,

I and Otlerings subject to cticinge without nDtice

WE ACCEPT

• VISA

•Add ».00 tor shipping fttiandnng

• MASTER CHARGE

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• CHECKS

■Otllo residents add 6'^i%

• MONEY riRI^ERS

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• C 0 U

CALL FOR INFORMATION ON

OTHER PRODUCTS

Circle 234 on inquiry card.

BYTE May 1981 373

circle 449 on Inquiry card.

BIOFEEDBACK

What is a growth experience? What is fun, and therapy too? What goes beyond games and lets you work directly with your sabconscious mind? What does all that and more, works with all popular computers, and goes on an RS232 port without external power supplies? (Parallel available too)

What, therefore, is a fabulous

ft

value?

The BIOCOM

Plot of GSR

(skin

resistance) during relaxation cycle. (-Relaxing here

"-Wide awake here

A whole new thing in computing! If you have any experience with biofeedback, you will love it. If you have only read about It, now is the time to see for yourself that it really works for you. Our booklet "Personal Growth With Your Computer", and our program documentation tell you how to:

• Observe and experiment with GSR

• Train yourself to relax

• Play lie detector and/or test subconscious response

at parties

• Play OUIJA, aloneorin agroup

• Create your own games/ experiments

Including manual, and our booklet "Personal Growth With Your Computer" or "Bend Your f\/lachine s Mind With Yours", and BASIC listings tor these programs;

GSR Plot

Computer OUIJA

Relaxation Trainer Lie Detector'Subconscious Response

For cassette or diskette, media charge S15 State system type to ensure compatibility, or if asking about parallel interfacing,

Dealer inquiries invited. Mail or phone orders to:

rOTA, Total Digital Engineering

210. D.W. HWY

S Nashua. N.H, 03060

603-883-0991

PIA Register Selection and Function

RSI

RSO

HI W

CRA2

CRB2

Function

0

0

X

0

X

Read or Write. DDRA

0

u

n U

I

Y A

write into \jr\M

0

0

1

1

X

Read from A-side Input pins

0

1

X

X

X

Read or Write CRA

1

0

X

X

0

Read or Write DDRB

1

0

0

X

1

Write into ORB

1

0

1

X

1

Read from B-side input pins

1

1

X

X

X

Read or Write CRB

X =

don't care

Control Register Bit Designations

7

6

5 4

3

2 1 0

CRA

IRQA1

IRQA2

DDRA '

CA2 Control

Access CA1 CorMrol

CRB

IRQB1

IRQB2

DDRB '

CB2 Control

Access CB1 Control

Control of CA2 Output Modes

Bits

CRA Bit 4

Bit 3

Mode

Description

'Handshake" on Read

Pulse Output

CA2 is set high on an active transition of the CA1 interrupt input signal and set low by a microprocessor "read A data" operation. This allows positive control of data transfers from the peripheral device to the microprocessor.

CA2 goes low for one cycle after a "read A data" operation. This pulse can be used to signal the peripheral device that data was taken.

Manual Output Manual Output

CA2 set low CA2 set high

Table 3: Control codes for the 6520. This device offers 20 pins that may be programmed (either individually or in groups) as input, output, or bidirectional lines.

6520 controls and modes are listed in table 3.

Construction Notes

The prototype floppy-disk controller was built on a Vector 3677 wire-wrap board (see photo 1). There are no special layout considerations, but adequate power supply bypassing must be observed (i.e., 0.1 /if capacitors across the supply and ground pins of each integrated circuit). A 16-pin DIP (dual in-line package) socket is used to connect the controller to a ribbon cable from the disk drive (use proper terminations).

Debugging

The read/write circuit can be debugged by using a microcomputer. Move the DRQ input (IC5, pin 11 in figure 4) from the 1771 to a convenient 6520 output. With the microcomputer running a diagnostic program, check to see that the WE pulse (IC3, pin 12 in figure 4) is about 14 /IS.

The data separator can be checked by usiitg a single-pulse input signal in

vss

I

1 •

40

1 "

CAl

PAO

2

39

I '

CA2

PAl

3

38

IRQA

PA 2

4

37

IRQB

PA3

S

36

RSO

PA4

S

35

] ■

RSI

PAS

7

34

RES

PAS

8

33

DO

PA 7

9

32

]

Dl

PBO

10

6520

31

]

D2

PBl

n

30

]

D3

PB2

12

29

]

04

PB3

13

28

]

DS

PB4

14

27

]

DS

PBS

15

26

D7

PBS

16

25

V

02

PB7

17

24

CS2

CBl

18

23

1 •

CS3

CB2

19

22

1 •

CSl

VCC

20

21

1 •

R/Vf

Figure 5: Pin description of the MOS Technology 6520 PIA. Use of this particular device allows easy interfacing of a disk controller to a 6502-based computer. One I/O port handles control signals; the other is used to transfer parallel bytes of data.

374 May 1981 © BYTE Publications Ire

Circle 77 on inquiry card.

Circle 416 on Inquiry card.

API 01 Apple II with Single Disk Drive $109

API 02 Apple 11 with Double Disk Drives 119

API 03 Apple II, 9 Inch Monitor & Double Drives ... 129

AP104 Apple ///, two additional Drives & Silentype 139

API 05 12 Inch monitor plus accessories 99

RS201 TRS-80 Model I, Expansion Unit & Drives 109

RS202 TRS-80 Monitor or TV set 84

RS204 TRS-80 Model III 129

RS205 Radio Shacl< Color Computer 89

P401 Paper Tiger 440/445/460 99

P402 Centronics 730/737 - Line Printer ll/IV 89

P403 Epson MX70 or MX80 89

CC90 Matching Attach^ Case 75

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58 122 112 85 106 85 138 93 128 152 102 117 90 112 122 47 78 117 51 58 70 48 57 154 175 181 154 80 142 39 48

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123 104 54 96 26 32

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HUTCHINSON

INDUSTRIAL

CORPORATION

40 West Highland Parl< Hutciiinson, IVlinnssota 55350 Teieplnone: (612) 587-5276

Circle 188 on Inquiry card.

BYTE May 1981 375

Circle 251 on inquiry card.

LET YOUR APPLE SEE THE WORLD!

The DS-65 Digisector® is a random access video digitizer which converts a TV camera's output into digital information the Apple can process. It features 256 X 256 resolution with up to 64 levels of grey scale. Scanning sequences are user programmable. On-board software in EPROM is provided for displaying digitized images on the l-ii-Res screen.

Use the DS-65 for: Precision Security Systems • Computer Portraiture • Robotics • Fast to Slow Scan Conversion • Moving Target Indicators • Reading UPC codes, schematics, musi cai scores and paper tape •

THE

DS-65 Price: $349.95 FSII Camera Price: $299.00 Combination Price: $599.00

NEW SOFTWARE FOR THE DS-65 IS NOW AVAILABLE ON DISK!

— Portrait System Software: This program includes captions and a credit line, reverse printing for T-shirt application and the option to save portraits on disk.

— Picture Scanner: Provides a variety of different dithering aigorythms for compressing the digitized image Into the Hl-Res screen.

Write or call for more Information I GIVE YOUR APPLE THE GIFT OF SIGHT!

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lieu of the 4.0 MHz crystal oscillator signal. The output of IC9 should count through the full range of 0 through 15, starting at i, while ICS should count from 4 through 8.

The INTRQ and DRQ signals were connected to PB6 and PB7 of the 6520 because powerful testing instructions are available for these pins. If problems occur in this area, these instructions will come in handy.

Testimonials

This system has been built by several people and has been proven to work with minimal debugging, using wire-wrap, Slit-N-Wrap, and Super Strip techniques. The circuits are not the simplest possible; we have interfaced a 5-inch disk drive to the KIM

and AIM systems using only three integrated circuits. The newer versions of the 1771, which allow the controller to be connected directly to data and address buses, do not need a 6520; but there is a case for isolating the microcomputer from the disk con

troller through a 6520. Whatever route you choose, this basic design will provide reliable, trouble-free operation.

In Part 2, next month, we will look at the software needed to use this controller.!

References

1. Allen, David M. "A Floppy Disk Interface." BYTE, January 1978, page 58.

2. Bal, Subhash, and Mil<e Wright. "LSI Controller." Electronic Design, September 1978, page 90.

3. Cannp, Roger, Terry Smay and James Triska. Micro Computer Systems Principles, 2nd Edition. Matrix Publishers Inc, 1979.

4. Elinoff, Gary. "Floppy Disk Memory Systems." Electronics Products, May 1978, page 39.

5. FD1771 A/B-01 Data Sheet. Western

Digital.

6. Hoeppner, John. "Interface a Floppy

Disk Drive to an 8080A-Based Computer." BYTE, May 1980, page 72.

7. /fiM Disl<ette General Information Manual, No. GA 21-9182. International Business Machines Corporation.

8. Nicholson, James H. "A Super Simple Floppy Disk Controller." Proceedings of the National Electronics Conference, Volume 33.

9. Operating and Service Manual No. 600203. Pertec.

10. Welles, Kenneth B. "Build This Economy Floppy Disk Interface." BYTE, February 1977, page 34.

( & Accounting 1

V « y

WILL SET UP YOUR ACCOUNTING RECORDS READY FOR POSTING ON YOUR MICROCOMPUTER

Complete system-general ledger, payroll, etc-intergrated, but suggest we start with general ledger

Features: Menu-driven, all reports are 8y2"xU", you pick account numbering system, one posting method provides that negative numbers are the credit side of the entry, a description field is associated with each side of an entry in update listings, budgeting

Cost for General ledger is $800, including initial set up of your accounts, software and manual, phone consultation and examining your files through a modem where you have that capability. Training at your site available at additional cost.

You must be or become familiar with Osborne manual, send us a good deal of information, have CP/M* and CBASIC2, and have at least 48K and one 8" double density disk drive.

* CP/M is a trademark of Digital Research

AN ACCOUNTING SYSTEM BUILT BY ACCOUNTANTS THAT OTHER ACCOUNTANTS WILL LIKE

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376 May 1981 © BYTE Publications Inc

Crrcle 223 on inquiry card.

Circle 60 on Inquiry card.

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The Art of Electronics

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BYTE May 19n 377

Technical Forum

Favorite Benchmarks and Other Programs

In the July 1980 BYTE, Carl Helmers wrote a Technical Forum entitled "Some More on Performance Evaluation" (page 216), in which he requested readers to send in benchmark routines that are "appropriate to the typical language and operating-system environment of the contemporary small computer." The following submission from David I Wilcox, of Mansfield, Pennsylvania, is one of the most noteworthy.

While in college, I was shown a simple way to calculate the number of decimal digits a computer retains in its internal representation of floating-point numbers. If:

A = 1./3.

then, by computing:

abs(logio(abs(l. - (A +A +A))))

HOW TO START A COMPUTER BUSINESS

"Computer Business Opportunities 1981" ^^^^||| annual report covers the best moneymaking Bj^^JHwA ventures - consulting, software packages, ^H|^^^l dealerships, systems houses, services, jBH^^^H rapping, maintenance, vertical markets and much more - plus 20 steps on how to start, where to be in the 80's, the small business market, common entrepreneur's mistakes, financing, marketing, competing with biggies, directory of services and self-help sources, going part-time to full-time. Nowhere under one cover is a better industry perspective for self-employment planning. Contents from key back-articles of "Computer Opportunles," the entrepreneur's newsletter since 1978, "Low Capital Computer Business Guide" (10,000 copies sold), and continuous research from our field seminars. Over 200 pages ringbound, $65.00, check, Visa, Mastercharge, or written company P.O. 30 day refund guarantee.

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the number of digits of accuracy is obtained.

The choice of 1./3. is deliberate because it is an infinitely repeating rational number in the binary-number system. Therefore, a difference between 1. and the sum A+A+A must exist in any attempt to represent 1./3. vfith a finite number of bits.

If the machine does not have the common logarithm function available, then compute:

l.nabs{l.-{A+A+A)))

The number of digits of accuracy is approximately the exponent of the result expressed in scientific notation. Better yet, use a calculator or math tables to find the common logarithm of the result.

The number of digits of accuracy available generally depends on both the machine and the language. This method offers a quick, in-the-store check of the actual number of digits used by a given system to represent floating-point numbers.

However, other letters we received bearing the "Favorite Benchmarks ' title contained still more programs written in Pascal or BASIC that shaved minutes or seconds from the prime-number-generating program used as a benchmark in Carl Helmers's article. Although we appreciate the attempt at participation represented by these letters, they missed the point expressed by Carl Helmers in that article: "...the goal of the exercise was not to code the most efficient algorithm. It was, rather, to code an algorithm that takes a measurable amount of time while performing a certain group of calculations." The same algorithm (preferably embedded in a common computer language) can then be run on several computers and the times compared as performance indices of the respective language/machine combinations.

For example, the benchmark given by David Wilcox, above, results in a number (calculated in this case, not timed with a stopwatch) that can be used to compare, say, an Atari 400 with a Commodore PET; the comparison being made is one of digits of accuracy.

One prime-number-generating benchmark sent to us gave two times, one for execution of the program using a video terminal and another using a printer. In my opinion, such a benchmark confuses the issue under consideration (computer speed in generating a given set of prime numbers). Unless a benchmark is trying to measure the efficiency of a given computer in displaying numbers, the interval being timed should end as soon as the first display is printed. This assumes, as was done in the prime-number benchmark, that all results are stored and the printing is done after the computation being measured has finished. In fact, I sometimes bracket the part of the program being measured with print statements that say BEGIN TIMING and END TIMING. This allows me to isolate the function being evaluated....GWM

378 May 1981 © BYTE Publications Inc

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BYTE Miy 1981 379

Book Reviews

TKeEpscn MX-80

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SPELLGUARD checl^s 20 pages of copy for spelling mistal^es and typos in less than a minute Can be used with many CP'fvl" word processors (Including WordStar) Lets operator review words it judges as potential errors. Operator may then change the suspect word or add it to SPELLGUARD's 20.000 word dictionary (dictionary size limited only by disk space). , $295 S230fS20

□ BASIC 80 by Micro. Version 5.2 and 4,51 included,,.. $350.00 $299f$30

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n muSIMP/muMATH by fVlicrosoft, muSlMP is a fast, efficient interpreter for sophisticated mathematical functions of up to 611 digits, muMATH is a package of programs written in muSIMP, Requires 40K.. , ,S250.00 $225/$25

TCS/Atlanta INTERACTIVE ACCOUNTING SYSTEM for small businesses. New release Each package can be used alone or posl automatically to the General Ledger, Available in compiled version (no support language needed) or in source (MBASIC required). Needs 48K RAM, 132-col printer, 24x80 CRT and CP'fvl" COMPARE AT UP TO $530/pkg.

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C PASCAUM compiler by SORCIM, Full Wrth implementation. Produces P-code. 5175,00 $139;$20

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Apple

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r' CCA DATA MANAGEMENT SYSTEM Stores and retrieves inlonnation in a way which lends itself to "row and column*' storage, retrieval and analysis. Includes $130 page manual, 598.50 $74.00

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Travels in Computerland, or Incompatibilities & Interfaces

by Ben Ross Schneider Jr Reading IVIA: Addison-Wesley Publishing Company

1974, ^ttfiVer, S6.50

Reviewed by Jonathan Jacky 6551 5th Ave NE Seattle WA 98115

How many seemingly impractical projects have been attempted only because someone thought, "That should be a trivial exercise for a computer"? So it seemed to theater historian Ben Ross Schneider Jr, when he proposed organizing a data base from The London Stage, an eleven-volume, 8000-page calendar of eighteenthcentury theater performances. As Schneider envisioned, "It would be like having an index to every kind of thing in the book, only the computer would even turn the pages and take notes for you."

As he became involved in the project, Schneider soon realized that what is conceivable for the computer is sometimes not easily accomplished. He learned that the system which saves the scholar months of repetitive clerical work may well require several times that much effort to get running. Schneider recounts his experience in Travels in Computerland, an entertaining book that gives a true-to-life case study illustrating information-retrieval techniques. It is the best account of an ambitious computing project I have read.

Schneider describes the problems of creating a computer-accessible data base from source text intended for human readers. He intended his data bank to produce, for

380 May 1981 © BYTE Publications he

GIrele 245 on Inquiry card.

example, listings of every role an actor played during his career. That meant sorting all the entries in The London Stage by actor—but The London Stage was not arranged by actor; it consisted of theater programs arranged chronologically. Each program included many items: titles, roles, actors... To enable the computer to identify each item, they must be clearly delimited and follow each other in undeviatirlg order.

Schneider believed that the syntax and typography of The London Stage satisfied these conditions, but programmer Will Daland recognized otherwise: "Too much variation," he explained. "A computer can't tolerate as much ambiguity as a human... The human being uses an immense store of experience to resolve ambiguities."

So they faced the mammoth task of recopying the entire text to better reveal its contents to the machine.

'The structure of The London Stage, which we had to describe before we could analyze it by machine, continually evaded us. To retrieve what was in it we had to know what kinds of things were in it and how this information was arranged. It was like nature itself. We always thought we knew more about it than we actually did."

Eventually they found the precise form in which the text would be presented to the computer, but only after Schneider learned to view his specialty from a new perspective. At one point he was startled when Daland, in trying to adlow for all conceivable possibilities, suggested a plausible variation in eighteenth-century casting practices that had never occurred to Schneider. He recalls: 'This episode is an example of how computer methods, by imposing logic, increase one's comprehension of one's subject. Aivd that is

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ri IVIAXELL 8" SINGLE-sided Double

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May 1981 © BVTE Publicaaons Inc 381

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why Will, who never studied it for an hour, could teach me something about theater

history."

The book vividly conveys the day-to-day feel of the project. The reader shares Schneider's dismay when, as deadlines approach and seemingly banal practical problems threaten to scuttle the project, the drama scholar must become a reluctant expert in the countless technical aspects of computing.

Because this work was done in the premicroprocessor era (about ten years ago), some of the problems seem very dated; inestimable difficulty resulted when terminals capable of producing lower-case characters proved to be imavailable. Other problems are perennially familiar; Schneider ruefully recalls the time invested in "persuading data-processing firms to meet declared standards, and explaining to sales representatives what their products were." In a final, ironic twist, humanist Schneider realizes that his achievement is poorly accepted and little understood by fellow schoUuB because he neglected to communicate effectively with them.

This book should be required reading for anyone plaiming to apply a computer to an intricate real-world activity, be it business or research. The nature of Schneider's project, his unusual perspective and lively writing, and particularly his vivid characterizations and keen appreciation of the way personalities shape projects, recommend the book to those on the fringes of the computing world. Travek in Computerland, or Incompatibilities & Interfaces is especially relevant to those technologically innocent people who think that computers are for doing math, and wonder how anyone could think a machine can help him appreciate a work of art.B

3S2 May 1981 © BYTE FabUcations Inc

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LANGUAGE SYSTEM W/PASCAL 420

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FREE CATALOG

over 150 Items ORDER TOLL FREE

(800) 327-7172

IN FLORIDA (305) 862-6917 nuf said

TRS-80 • APPLE 2 • ATARI • SCORCERER

>

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51

do o

INTERNATIONAL

A DIVISION OF SCOTT ADAMS. INC

BOX 3435 • LONGWOOD.FLA 32750

Circle 454 on Inquiry card.

Circle 9 on inquiry card.

BYTE May 1981 383

Ask BYTE

Hi' tLnfli I ^'

Conducted by Steve Clarcia

Here's LED In Your Display

Dear Steve,

I enjoyed your article "Self-Refreshing LED Graphics Display" (October 1979 BYTE, page 58), and think I can use such an output display. My present system is a KIM-1 computer with an 8 K-byte memory board. I use the KIM-l's keypad and LED display for input and output, but I'm having difficulty expanding the display board.

Your design is an 8 by 16 display, but I would like to

expand that to 8 by 64; then I could have a small amount of alphanumerics and graphics.

Near the end of your article, you mentioned that to

expand on your design, simply add more memory and column decoders. Please be more specific. Would I have to use six address lines, and spread this out over four 74154 l-of-16 decoders? I assume a total of eight 7489 memory devices would be needed. How do I tie this stuff together? Would this affect the refresh and scan rates? Could I substitute LStype logic circuits in your design?

Charlie Timbers

There are several ways to

expand the basic 8 by 16 display into an 8 by 64. The easiest thing to do is to make four of the basic units, then change the addressing to be

Model EP-2A-87

EPROM Programmer

NEW - CRT ENTRY MODE

The Model EP-2A-87 ' ^^^^Klirj EPROM Programmer has an

: "-»^;*f J RS-232 compatible interface

'i'^'J^^O'm ^"'^ includes a 2K or 4K

S'"' *iliKf buffer. Durinq the ON-LINE

Mf ^H^'- mode, another computer

^ A:^ MB can down-load to the buffer.

Only two casy-to-implement commands are available to an external computer. (Load buffer and read buffer.)

In the OFF LINE mode, the EP-2A-87 will program, verify, test buffer, and load the buffer from the EPROM socket. During the programming cycle, the EPROM is checked before programming to insure that it is erased and after programming it automatically uenties that programming is con-ect. Power requirements are 115 VAC 50/60 Hertz at 15 watts.

Part No. Description Price

EP2A-87 1 Programmer ujith2K buffer $575.00

EP2A-87 2 Progranirrerwitfi4K buffer 65().(X)

Non standard voltage option 1220 u. 240 V, 100 v) 15.00

PM O Personality Module, programs TMS 2708 18,00

PM-1 Personality module, programs 2708 18.00

PM-2 Personality module, programs 2732 34.00

PM-3 Personality module, programs TMS 2716 26.00

PM 4 Personality module, programs TMS 2532 34.00

PM5 Personalitymodule.programs2716.TMS2516 18.00

PM 6 Personality module, programs 2704 18.00

PM-7 Personality module, programs 2758, IMS 2508 18.00

PM-8 Personality module, programs Motorola MCM68764 36.00

Optimal Technology, Inc.

Blue Wood 127 EuIysviUe, Vir^nia 22936 Phone (804) 973-5482

four blocks of sixteen, for a total of sixty-four 8-bit output ports. To accomplish this, the address decoding presently done by ICl and IC2 must be changed. Figures

la and lb should help.

You can use LS TTL (transistor-transistor logic) devices for those integrated circuits that have an equivalent. Some don't. ...Steve

Figure 1

A3 '

A2 •

Al •

AO '

BANK 3 ■

^BANK 3

^BANK 2 I IN PLACE OF 10 V ) FORMER

^ >BANK1 f ICl PIN 8

^ BANK 0

■^1

TO ALL BANKS

BANK 2

BANK 1 •

BANK 0

S BY 16

0

8 BY 16

8 BY 16

A0-A3

S BY 16

384 May 1981 © BYTE Publications Inc

Circle 301 on inquiry card.

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ROBOuIOage

The Annual 1981

ROBOnCS INDUSTRY DIRECTORY

The Directory contains comprehensive listings of:

• Robot Companies that manufacture com

plete systems

• Related Manufacturers of robot modules

and components

• Institutions, laboratories, and universities

performing research related to Robotics

• Consulting firms with expertise In the field

Each entry will consist of a brief description of the product line, activity, service, etc., with the name, address, and phone number of

a l<nowledgeable representative.

Who needs the Robotics Industry Directory?

• Engineering Personnel: technical proposal preparation, technology surveys, systems integration, cost estimation.

• Management: consulting services, feasibility studies, inhouse requirements. • Procurements: bid pacl<age preparation, general equipment specification, sources, costing.

• Marlceting: product planning, market surveys, sales projections, competitive appraisal.

Order Today — Only $24.95

(Canada $26.45 US, other Foreign $31.45 US) RolMtics Industry Directory, PO Box 372, Tujunga, OA 91042

NEW*

APPLE GRAPHICS

VISICHART

SCIENTIFIC PLOTTER

CURVE FITTER

s I

-1*—m M U ajL

7^

-i > » 1 «

I jMiai

T 1 » 1 1 rf*

FOR LABS BY PAUL K. WARME

SCIENTIFIC PLOTTER 48K APPLE ii+,$25

Draws professional-looking graphs of your data. EASIER, FASTER, NEATER and more ACCURATE than handpiotting. You choose data format, fength and position of axes, 20 symbols, error bars, labels anywhere in 4 orientations, etc. includes 5 DEMOS on clisl< with 30-PAGE MANUAL.

CURVE FITTER 48K APPLE II+, $35

Selects the best curve to fit your data. SCALE, TRANSFORM. AVERAGE. SMOOTH. INTERPOLATE (3 types), LEAST SQUARES FIT (3 types). EVALUATE UNKNOWNS from fitted curve. Includes 5 DEMOS on disk with 33 PAGE MANUAL.

VISICHART™ 48K APPLE II+,$75

NEW tools for lab data management. FAST plots of -i data sets with SCROLL ING in 4 directions. ZOOf^ scaling on X and Y axes, 2 types of graphic CUR SORS and on-screen STATUS REPORT. PLOTS A/D INPUT white sampling. ADD, SUBTRACT, MULTIPLY. DIVIDE, INTEGRATE, DIFFERENTIATE AVERAGE or NORMALIZE data sets witt) SIMPLE COMMANDS. Ideal lor spec Ira, chromatograms, rate curves, etc. Includes SAMPLE DATA on disk with 28-PAGE MANUAL.

SPECIAL! All 3 programs on one disk, only $120. Since each) program uses tt^e same data format on disk, data may be shared.

BUY THESE PROGRAMS AT YOUR LOCAL DEALER OR ORDER

DIRECT. For more information, ask for FREE brochure or send $5 for any manual (S12 for all 3). deductible with purchase. Add $1.50 shipping on all orders. For laslest service, call in your VISA or Master Card order.

INTERACTIVE MiCROWARE, INC. P.O. Box 771, Dept. B State College, PA 16801 CALL (814) 238-8294 for IIMMEDIATE ACTION

lUjI

A REFURBISHED "SELECTRIC" ASCII TERMINAL FOR THE SMALL BUSINESSMAN OR SERIOUS HOBBYIST

The AJ 841 I/O terminal. Now available from dealers nationwide.

Demand for our AJ 841 I/O computer terminal has been great. And now/ it's getting even greater So call your local computer shop dealer right away. Supply is limited! You may never have another opportunity lil<e this one to buy your own professional terminal.

The AJ 841 features:

• Serial RS-232 interface

• ASCII code

• 14.9 ops printout

• High quality Selectric printing

• Heavy-duty Selectric mechanism

• Off-line use as typewriter

• Documentation Included

• 30-day warranty on parts and labor (details available on request)

Call toll-free now

For location of your nearest AJ dealer, call toll-free:

800/538-9721

California residents call collect 408/263-8520, Extension 263.

Available only In the continental United States

Suggested retail price

JACOBSOIM

Circle 25 on iriquiry card.

BYTE May 1981 385

GIFTS FROM PROMETHEUS

NEW for APPLE II

Advanced products Down-to-Earth^^^H PRICES .^^^■■i

(1)

DUALSERIAIirCARD

All functions of two . >''^v?j=f "pi" ■ independent serial * cards on one board-plus

more. Provides Apple II''' users with two simultaneous asynchror nous serial channels. DSC-1 appears as two separate logical serial cards to the Apple ll'Sl Fully software compatible with all Apple ll's'^' and Microsoft software. 2716 EPROM used for easy driver modification. In addition, the second serial channel supports these extra features: • Strapable DCE/DTE. • Secondary RS-232 handshake functions (DCD, DTR, DSR) • Strapable logical slot location and hardware looks like it's another slot. Order: PP-DSC-1 @ $189.00 each

DUAL SERIAL/PARALLEL GARD-1. As with the Dual Serial Card-1 (above), the Dual Serial/Parallel-1 provides Apple users with simultaneous use of one full serial port and one parallel port. Both ports strapable for any Apple peripheral slot. Fully compatible with all Apple and Softcard (CP/M) software. Drivers for serial interface and Centronics parallel interface are contained in modifiable industry standard EPROM. Serial port is configured like DSC-1. Order: PP-DSP-1 @ $189.00 each.

MEMORY EXPANSION MODULE-1. Expand yourApple \mo afull64K RAM system with highest quality 16K dynamic RAMS. Fully buffered to provide reliable operation - even with fully loaded Apples. Total compatibility with Micrbsoft Soflcard'^'/CP/M^^' and all Apple software. Supplied complete with installation instructions and test program.

Order: PP-MEM-1 @ $149.50 each. PASCAL MT-l- MEM«1. A modular native Z-8G code Pascal compiler. ISO standard. Includes a MEM-1 {detailed above): Have a full Pascal compiler at half the Apple price. Requires a Microsoft Softcard® and two ' disk drives. Note that the Pascal MT+ alone is normally $250.00.

Order: PP-PMT-1 @ $299.00 each.

:?16K RAM ADD-ON KITS. ForTRS-80 and Apple ll'^'. Eight (8) fullSpecification industry standard 16K RAMS. These are not seconds.

Order: PP-RAK-16 @ $29.00 each.

All Prometheus boards are completely tested and burned-ln prior to shipment. One-year warranty covers parts and labor. MONEY BACK GUARANTEE: Order now without risk. Boards may be returned, in good condition, after up to 10 days .'6f trial for a full and prompt cash refund. California: add 6% tax; BART Counties, 6V2%. Orders under $150, add $3.00 postage, for handling ctiarge. Freight allowed on orders over $150. Dealer inquiries invited, f Quantity discounts available. [

PROMETHEUS

PROMETHEUS PRODUCTS INCORPORATED

4509 Thompson Ct. • Fremont, CA 94538 • (415) 791-0266

RBglsteijediTradftMarks: (1) Apple Computers, Inc. (2) Microsoft ConsurtierProducts (3) Digital Research, inc.

One Shall Be Two

Dear Steve,

We use Maxell MDl singlesided 5-inch floppy disks on our Apple II. We noticed that the disks have a head-access slot on both sides, so we decided to experiment. We cut a write-enable notch on the opposite edge, and, to our surprise, we were able to write a full 16 sectors on the other side of a single-sided disk. A scan of the disk showed the written data to be in good shape and no physically damaged areas. So, what is the difference between single-sided and double-sided disks—and why purchase a double-sided disk at the extra cost? Michael Berch John Oswalt Berkeley CA

The answer to your question involves how disks are manufactured and tested, rather than any physical difference between them. Both sides of a disk are usually capable of data storage, hut, on a single-sided disk, only one is guaranteed.

When a disk is made, it is tested for data retention. This means writing data (usually at a higher density than you will ultimately use) onto the disk and reading it back. If all goes well, the disk is certified. On double-sided disks, both sides are checked and certified.

As a matter of economics, some manufacturers do not bother to check more than what is required to meet production schedules. For example, if 100,000 disks are made and 10,000 must be certified as double sided, the manufacturer may stop testing both sides after getting 10,000 good ones. This often requires checking 15,000 disks to get the 10,000 that pass. Most often, the 5000 rejects end up in the single-sided

386 May 1981 © BYTE PubUcatipns he

Circle 336 on inquiry card.

circle 261 on Inquiry card.

Circle 178 on Inquiry card.

reformaITer

© MicroTech Exports 1980

With REFOR/MATrER f disk utilities you can read and write IBM 3740 and DEC KT-ll sta^e density formatted diskettes on your CP/M® system.

RBfORMATTER enables you to access large system databases, improve data exchange with other organizations, increase program development capabilities, and use your micro in distributed processing.

REFORMATTER programs feature bi-directional data transfer and hll directory manipulation. ASCII/EBCDIC conversion provided with CP/M <-*IBM. MP/M is nowfifUy supported.

Program Data Sheets, Application Guides, and Machine Compatibility Guides available.

Each program $195.00 from stock. Specify CP/M IBM or CP/M *->■ DEC. Order from MicroTech Exports, Inc., 467 Hamilton Ave., Suite 2, Palo Alto, CA 9430; □ Tfel: 415/324-9114 □ TWX: 910-370-7457 MUH-AITOS □ Dealer and OEM discounts avaUable.

^Sm CP/M^ is a registered trademark of Uigllal Rescarcli. Wm

ode

An Atlanta bulletin board system uses a Hayes S-100 modem around the clock. Since March 1979, it has logged over 21,500 calls and been down a mere 10 minutes. For performance like this, depend on the Hayes Micromodem 100.™ Features include automatic dialing/answering, 45 to 300baud operation, abuilt-in serial interface and direct connection to any modular phone jack.

The Micromodem 100 —and Micromodem IV" for Apple 11* computers — are now available nationwide. Call or write for the name of your nearest dealer.

(B Hayes

Hayes Microcomputer Products Inc.

5835 Peachtree Comers East, Norcross, GA 30092 (404) 449-8791

II are trademarks ot Hayes Mic

Products inc TM Apple Compum

SI^TIsvsTEms, mc

P.O. Box 1225,2 Washington Street,Haverhill, Ma. 01830

SPECIALISTS IN

FULL SERVICE SYSTEMS

Circle 354 on Inquiry card.

BYTEmy 1981 387

ENTREPRENEURS

Iml^^l Irl I MORE THAN EVER IN THE MICRO

COMPUTER INDUSTRY.

The shortage of knowledgeable dealers/distributors is the #1 problem of microcomputer manufacturers. Over 300 new systems houses will go into business this year, but the number falls short of the 1200 needed. It is estimated that the nationwide shortage of consultants will be over 3000 by 1981. The HOW TO manuals by Essex Publishing are your best guide to start participating in the continued microcomputer boom.

HOW TO START YOUR OWN SYSTEMS HOUSE

6th edition. March 1980

Written by the founder of a successful systems house, this fact-filled 220-page manual covers virtually all aspects of starting and operating a small systems company. It is abundant with useful, real-life samples: contracts, proposals, agreements and a complete business plan are Included in full, and may be used immediately by the reader

Proven, field-tested solutions to the many problems facing the

small systems house are presented From the contents:

• New Generation of Systems Houses • The SBC (vlarketplace

• N/larketing Strategies • Vertical Markets & lAPs • Competitive Position/Plans of Major Vendors • Market Segment Selection & Evaluation • Selection of Equipment & Manufacturer • Make or Buy Decision • Becoming a Distributor • Getting Your Advertising Dollar's Worth • Your Salesmen: Where to Find Them • Product Pricing • The Selling Cycle • Handling the 12 Most Frequent Objections Raised by Prospects • Financing for the Customer • Leasing • Questions You Will Have to Ansvuer Before the Prospect Buys • Producing the System • Installation, Acceptance, Collection • Documentation • Solutions to the

Service Problem • Protecting Your Product • Should You Start Now'' • How to Write a Good Business Plan • Raising Capital

No. 10

'1

J

COMPUTER CONSULTANT

HOW TO BECOME A SUCCESSFUL COMPUTER CONSULTANT

by Leslie Nelson, 2nd revised edition, Jan 1981 Independent consultants are becoming a vitally important factor in the microcomputer field, filling the gap between the computer vendors and commercial/Industrial users. The rewards of the consultant can be high: freedom, more satisfying work and doubled or tripled income HOW TO BECOME A SUCCESSFUL COMPUTER CONSULTANT provides comprehensive background information and step-by-step directions for those

. B interested to explore this lucrative field:

^^^^H H • Established consulting markets • How to get started • Itemized

^^^^H - , H start-up costs • Are you qualified'' • Beginning on a part-time

^^^^^^^^^^^^^^H basis • The Marketing l<it • Should you advertise? • Five ^HB^^^^MI^M^B marketing tips • Getting free publicity • How much to charge ^■■■■■■■■■■■■M • When do you need a contract? • Sample proposals • Which jobs should be declined • Future markets • The way to real big money • Avoiding the legal pitfalls'How consultants'associations can help you 'The National Reg ister oi Computer Consultants • How others did it: real-life sample cases • and much more.

$28.

FREE-LANCE SOFTWARE MARKETING 3rd edition, June 1980 Writing and selling computer programs as an independent is a business where • you can get started quickly, with little capital investment • you can do it lull time or part time • the potential profits are almost limitless. Since the demand for computer software of all kinds is growing at an explosive rate, the conditions for the small enti'epreneur are outstanding.

This manual will show you how to sell yourown computer programs using these proven techniques: • direct to industries • through consulting firms • through manufacturers of computer hardware • in book form • mail order • through computer stores. It will show you how to profitably sell and license all types of software ranging from sophisticated analytical programs selling forthousands of dollars, down to simple accounting routines and games for personal computers.

The book will guide you step by step through the process of $30. No. 32 marketing, advertising, negotiating a contract, installing software,

training users and providing maintenance and support. It also contains sample software contracts that have been used in actual software transactions. Also included are tips on how to negotiate ' with) a large corporation, ways of avoiding personal liability, techniques for obtaining free computer time and hints on how to run a free-lance software business while holding a full-time job.

Address .

City

Card »

. State .

-Zip

ESSEX PUBLISHING CO. oept 2 mmm i^Sj

285 Bloomfield Avenue • Caldwell, N.J, 07006 i' ■ I I^WB

Older books by number Send check money order (U S S), VISA or Master Ciiarge « Publisher pays 4th class shipping For UPS shipping (USA only) add SI .00 per book For Air Mail shipping add S2,50 per book in the USA. S6.00 In Mexico and Central America. S12 00 per book elsewhere. N.J residents add S% sales tax. □ No. 10 ONo.ie ONo 32 □ Check enclosed dCreditcard □4thclass DUPS OAlr

Name

Exp.

For faster shipment on credit card orders call (201) 783-6940 between 9 and 5 Eastern time.

stock (presuming thai one side was good). The remaining 85,000 are only checked for one good side.

In your case, one of the following situations may exist:

1. Both sides were checked, but the manufacturer decided to put the disk in a singlesided envelope anyway.

2. The second side was untested by the manufacturer.

3. The second side failed the manufacturer's data test, and the disk could only be certified as single sided.

In the first case, you are handed a golden opportunity. Cut another access hole and use the other side. In the second and third cases, you are playing the odds. Of course, all three are merely conjecture, since the manufacturer doesn't specify the performance capabilities of the uncertified side.

I suggest that you only use the modified disks for noncritical storage. While it may appear that your experiment has always worked in the disks you've tried, this may be more of a testimonial to the quality of that particular manufacturer's product than a general axiom for all disk users. ...Steve

RF Substitute?

Dear Steve,

I've been thinking about buying either an Apple II or an OSI C4P. While saving money and trying to make my decision, I ordered an Interact computer from ManuTronics. Each of these devices needs either a monitor or a tele'vision set with an RF (radio-frequency) modulator. Since I already have a videocassette recorder, can I hook the device into the video input jack of the cassette recorder and use its built-in RF modulator (charmel 3 for

388 May 1981 © BYTE Publicatioiu Inc

Circle 155 on inquiry card.

Circle 379 on inquiry card.

Circle 68 on inquiry card.

TWICE THE BYTE!

8" DISK CONTROLLER

NOW—DOUBLE SIDED OPTION!

• DOUBLES APPLE ][ STORAGE

• APPLE DOS COMPATIBLE

• SHUGART 800 OR 850 COMPATIBLE

• IBM 3740 DATA ENTRY CAPABILITY

• CP/M, UCSD PASCAL CAPABILITY Available at your local APPLE Dealer: $400.

SORRENTO VALLEY ASSOCIATES 11722 SORRENTO VALLEY RD. SAN DI^GO, CA 92121

WORKING OVERTIME

APPLICATIONS WHICH SAVE TIME

Payroll, Word Processing, Accounting & Financial Management, Educational Administration, Legal, Medical & Dental Systems

Check your Local Dealer or Contact:

Ctiofie/ fnonn & A/zeciole/

7594 San Remo Trail Yucca Valley, Ca. 92284 (714) 365-9718

Apple II

TRS-80

Tl 99/4

Colorful Graphics Programs for Apple 11, Atari, TI 99/4

LAND WAR:

A unique computer war game. Similar to board war games, but the playing field is drawn on the screen in hi-resolutlon color. The players must maneuver infantry and armored units over terrain that includes rivers, forests and cities. To win, a player must occupy his opponent's city, and destroy his opponent's armies. Two players can oppose each other, or one player fight a computer general.

All this for only $20.00

Apple II with 2i|-K RAM; Atari with 24K RAM.

Not available for TI

COLOR SOFTWARE, PO Box TkZlk, Indpls, IN '^6224

Namei

Streeti

Cityi

States

Zipi

ComputerI

Apple II

Atari

TI 99A

Programs desired;

Send for illustrated catalog with these and other programs which all make full use of the graphics capabilities of these computers.

Land War Startrek Dry Well Baseball

($20) ($15 $15 ($25)

Add one dollar for first class postage.

Total enclosed.

3-D STARTREK I Play the popular computer game In three dimensions instead of two. Hi-resolution display shows stars and Klingons scaled according to distance from the Enterprise. Discover new planets, destroy Klingons, and save the Federation.

$15.00

Apple II,32K RAM! Atari,16K RAMi and TI

DRY WELL • Entertaining strategy game of oil exploration. Discover the pattern of the oil deposits and maximize the profits of your oildrilling company. Pattern of deposits is different every game.

$15.00

Apple II,24k ram, ROM Applesoft,- Atari, 16K RAM; TI 99A

MAJOR LEAGUE BASEBALL:

strategy game based on I98O Major League teams. You manage your favorite team and make all the decisions. Includes 26 teams with 25 players per team. Also includes utilities to make and modify your own teams.

$25.00 (on disk) for Apple II only. Regulxes 48K RAM, ROM Applesoft, and one disk.

Circle 72 on Inquiry card.

BYTE May 1981 389

TEXAS COMPUTER SYSTEMS

Radio /haek

Authorized Sales Center We offer the lowest prices on

TRS-80

MODEL II 64K $3349

Model III 16K Llll $849

Color Computer 4K LI $339

An excelleni compuler for your business needs Easy expandability & compatibility. No (ormal operator training needed All accessories available -disk expansions, printers and software. Quick delivery-airfreigtit Irom Dallas.

Model III 32K 2 Disks - SCall

Pocket Computer & Acc. SCall

PRINTERS

DAISY WHEEL II

S1695

Carbon ribbon typewriter quality for word processing. 43 cps. Standard Centronics parallel interface. Full 16"

width, individual sheets or friction feed Tractor teed

,5?S0 ">lr.i Pastes! D.aisv WhppI .ivailatilp .at lliis prire

EPSON MX-80 $Gall

Letter quality matrix similar to Line Printer IV and Centronics Printer bul has full software control of 40, 80, 66 or 132 columns. 80cps bidireclional, tractor feed, disposable printhead. $300 less than nearest competitive printer. Best tiuy in multi-strike letter quality printer. Lists al $645. Our price includes cable & shipping.

ANADEX 9500/9501 $1385

quHr t pHu. ID. ^i, 13^3. ie.7 ml.« w a tpi. ]

LINE PRINTER V

$1616

LINE PRINTER VI

S1015

teOcfH. Detiofwd lor huvy IwilnMi UM. BdmcHDnil. M

CUSTOM SOFTWARE FROM TCS

Model I & III Programs tor the Epsofi MX-80 Printer

gal 6 proonm lor one low pnce a library on disk or Upe ol ptognms and SUbrautinn aasigneil lor uimng nunmum u^t oi ine Epson MX-n pnnlH^

duel Urge giapnic tenars and dump irwr vnru from any Basic program

DEFSTATE/SUI-CollKllDn ot prB-dallnwl c

Irom any Basic program Auto linecenlerlng, lillss with bofdars. ale . inslanlly wilh one word cDtnmandS

DEMD/iXS-Tulofial program wiin lOD's ol REM remarks loguids you fh'u Ihe ujb o( four computer

JKL PATCH-A paicn 10 newOOS 2 1/80's JKL scraan pnniar func

ideas coricBpis & irouo'e si

M.'ir'r-.i ■ nr Ml T;.pf. or Disk

Si'S.'jL. ■ . -'.,;(! Epson pniitfjr

The DOS Disk Library of Programs

A iiei,irv 01 '] programs ler NEWDOSBO NEWDOS ? I. IRSDOS

tenama, ra-lormai, Bic . Quickly w>in minimum lypmg Supar graphic displays lor easy usa

FILIMAIHT-Cieatas master dirKlory ol all tiles on your lioiary ol diskattas Master lile is handled on disk, not on memory, tor miximum speod Access any lue "\ 2 seconds 48K supports ZOO d'Skenas S^KabouUlX) Takes less than riour lo run too diskettes thru

CHDINILO/Ut-A super chaining lilo crsalwn editor & aisambler

program Hsall. Fast & iltlclottt for home user wtlti lets Itian lOd

Model i or III Disk S39.95 for all 5 programs

Infinite Basic DIskotte

A disk' 'e ol proqrdms wiitlsn m HACET's inliniia Basic User mu fint Inhniie Basic Iboin modules) Eilramely useful program wi REM remarks lo flutda you in aasy use ot Iho lOO eilia commim orovidsd Dy itiis soltwara sysiam

Included on the disk is program lo maiiiiain a Vioao Cassatta Librar anin-mamoty Mailing Lisl, adamonstration ol Matrix Technlquas ai ■ouatton solution, a screen input syilam rouilno. Also a compK amdo on InXnilo Sasic wllh valuable Inlormattan on commands tn

are glassed over in Ihe original documenlaiion

I [VM^

S39.95

We can Air Freight from Dallas to major a/p near you lor fast, efficient service. Call for information

'Payment Money Order Cashitr's Check. CartllM Chock Personal Checks require 3 wks to clear VISA. UC. add 3% •pr.ces subiecl fo cnange any lime

*No uu oul-ol-iiale TX add 5K 'All ilemj new. guaranteed Dy manufacturer 'Delivery subjecl lo availability ■Shipping eiira. quoted by phone

TEXAS COMPUTER SYSTEMS

DSMCRs Siles Center F701

Box 1174, Brady, Texas 76825

TOLL FREE Number 800-351-1473

Texas Residents 915-^97-0673

Ask BYTE.

my area) for my display? John Ramler Alexandria VA

/ was hoping someone would ask that question.

Videocassette recorders have an input jack that is normally intended for use with a TV camera. In general, a camera has a 1-volt peak-topeak output signal into a 75-ohm load. Most computers with a straight video output try to conform to this specification, so they should be compatible.

To make sure. I connected

the output of an Apple II to the camera input of a Magnavox videocassette

recorder. The camera/tuner and VTR/TV switches were set to camera and VTR, respectively. In my opinion, it worked well. However, it was necessary to reduce the TV's color-control setting to keep the letters from running together. Once adjusted properly, it made a satisfactory monitor.

An additional benefit of this technique is that you can record anything on the screen. ...Steve

Simple Case Conversion

Dear Steve, I read Roger L Degler's "A

Lowercase to Uppercase Converter," and it seems I have a similar problem. (See the September 1980 BYTE, page 326.) I own an uppercaseonly keyboard, but I would like to use lowercase on my video-interface board. Is there some sort of uppercaseto-lowercase converter I could put between my keyboard and video board and still have an operational shift key? I'm sure many BYTE readers have the same problem.

Andrew Meyer White Plains NY

To get lowercase codes from a keyboard that has uppercase-only output, it is necessary to make the fifth bit high (assuming 7-bit ASCII code), so that an "A" (1000001) becomes an "a" (1100001), and so on.

If your keyboard output is DTL (diode-transistor logic), RTL (resistor-transistor logic), or TTL (transistortransistor logic), it can be modified a number of ways. One method is the way Roger Degler suggested in his article. Another way, simpler but much less sophisticated, is shown in figure 2. You'll note that pressing the "shift key" causes bit 5 to be high. ...Steve

BIT 5 IN »

Figure 2

390 Uiy 1981 © BYTE Publications Inc

Circle 404 on inquiry card.

circle 67 on Inquiry card.

COMPUTER HOBBYIST SPECIALS!

Daisy Wheel Terminals

RS-232, used, off-lease. Features Diablo Hytype 1 printer, up to 30 CPS, plot & text modes, dual pitch and much, much more. Includes data, operation manual, schematics. "As-is" machines may need some service.

TESTED & FUNCTIONAL

AS-IS ONLY

AddS40forHcllg.andPkg. Pay Shipping When Delivered.

1299°? «899o?

SELECTRIC" TYPEWRITER TERMINALS

15" "Selectric" typewriter terminals are complete with solenoid drivers and RS-232 Serial 10 circuitry. BCD or correspondence code. Each unit includes operational printer, power supply, and untested RS-232 I/O board. Features:

•Full KSR Capability CPS Rale

•88 Character Sfit •Standard Typewriter KBD

[Upper and Lower Case) •117 VAC.

• 134.S Baud I/O 60 Hz Operation

• 132 Col.

No type element inolu<ietJ^ Line cord and some data included.

* Reg. Trademark ol IBM Corp.

-Add $20 For Hdlg. & Pkg.

SDC Colli Terminal... 5489.00 Correspondence Code Terminal

$569.00

Prlnlor Maintenance Manual $20.00

EACH I

Pay Shipping When Del.

WriteorCallforourBargain-PackedPERIPHERALFLYERI! Prices are Subject to Change on All Hems

CFR Associates, Inc.

^ PHONE ORDERS:

MAILORDERS: 617/372-S536 WAREHOUSE:

Box 144 Newton N H ISoiry. No Collect Citlsl ' 18 Granite Slreel

' ■ ■ KlaslerCtiarse S VISA Welcome

WAREHOUSE:

3 Granite Street Brhin. Mass. 01830

Circle 327 on inquiry card.

Attention TRS-80 Mod II owners: P&T CP/M® 2 has more to offer!

More Disk Storage SSBK bytes with double density on standard single sided disk drives. It that's not enough, versions are available for double sided expansion drives(1.2M bytes per disk) and the Cameo Hard disk system (10IV1 bytes.) More CRT Functions P&T CP/M 2 has the most advanced screen driver available tor the Mod II Including: erase to end of line/screen, insert/delete line, cursor addressing, non-scrolling area on screen, and much more.

More Serial I/O Capabilities The serial drivers in P&T CP/M 2 support ETX/ACK, XON/XOFF, and request to send handshaking. Direct control of serial ports Is also available for special applications.

More Documentation We provide the standard CP/M manuals and our own 150 pagis manual written specifically tor P&T CP/M 2. Mora Utilities We have added 14 of our own utility programs tor the Mod II to the standard CP/M utilities. More Useful System Functions P&T CP/M 2 has all sorts of useful features you won't find elsewhere: type-ahead buffer for keyboard input, system time of day clock, automatic program execution and lots more.

Standard P&T CP/M 2

P&T CP/M 2 for Shugart 850 2 sided drives

PST CP/M 2 for Cameo Hard Disk system

$185 $220 $250

We also carry other software packages, single <& double sided expansion drives and the Cameo Hard Disk System. Write for details.

epaid COD. tvlasterch. iinpinc) exira California

rge or Visa orders accepted residents add B^r sales lax

PICKLES & TROUT

P. O. BOX 1206, GOLETA, CA 93116, (805) 685-4641 CP/M is a trademark of Digital Research Inc. TRS-80 is a trademark of Tandy Corp.

Big Savings On Atari & PET!

No Risk - No Deposit On Phone Orders - Shipped Same Day You Call° - C.O.D. or Credit Card

On all in stock units

Atari® 800'

List $1080

only $759

ATARr

Please Cali Between 11AM & 6PIVI (Eastern St&ndard Time)

(800) 233-8950

400 8K 419

400 16K 449

410 Recorder 62

815 Disk 1199

810 Disk 489

822 Printer 359

825 Printer 779

830 Modem 159

850 Interface Module 179

CX852 8K RAM 94

CX853 RAM 149

CX70 Light Pen 64

CX30 Paddle 18

CX40 Joystick 18

CX8100 Blank Diskettes (5/box) .. 22

CXL4104 Mailing List $17

CX4107 Biorhythm 13

CXL4007 Music Composer 45

CX4110 Typing 20

CX4101 An Invitation to

Programming 17

CXL4015 TeleLink" 20

CXL4004 Basketball $30

0X4105 Blackjack 13

CXL4009 Chess 30

CXL4011 Star Raiders" 45

CX4111 Space Invaders 18

CXL4006 Super Breakout'" 30

CXL4010 3-D Tic-Tac-Toe 30

CXL4005 Video Easel" 30

To Order:

Phone orders Invited (800 number is for order desk only). Or send check or money order. Equipment shipped UPS collect. Pennsylvania residents add 6% sales tax. Add 3% for Visa or MC. Equipment is subject to price changeand availability without notice.

Computer Mail Order 501 E. Third St. Wiiliamsport, PA 17701

commodore

4032N.

61090 CBM 2022 Printer.

4032B 1090

8032 1-499

NEWVIC - 20 299

8096 1890

CBM 4040 Drive. CBM 8050 Drive. CBM G2N Drive . PET-IEEE Gable.. IEEE-IEEE Cable.

675 1090 1420 87 37 46

Software

WordPro 3 (40 col.) .... $186

WordPro 4 (80 col.) .,.. 279 WordPro 4 Plus

(80 col.) 339

Visicalc - Apple 122

Visicalc - Atari 163

Visicalc-PET 163

Commodore

Tax Package 399

Microtek - for Atari

Microtek 16K RAM 99

Microtek 32 K RAM 189

Disks

Sycom S'A" Single Density Box of 10 $29

Maxell S'A" Fioppy

MD1 Single Density

Box of 10

MD2 Double Density Box of 10

34

44

Printers

Trendcom 200 489

Epson MX-80 539

Commodore Tally8024... 1679

(717) 323-7921

circle 444 on Inquiry card.

BYTE May 1981 391

Ask BYTE

IC2

74LS86

1N4002

XT

-<DATA ACCEPTED

Figure 3

Where'd You Get Those Beepers?

Dear Steve,

I'm connecting a keyboard to a parallel port. I need a simple circuit that beeps if a pulse does not happen on the Data Accepted line within a set period of time after the pulse on the Data Ready line.

Can you help me? David Smith North Bergen NJ

There are many ways to design (he circuit you want. One method is shown in figure 3. This circuit uses three monostable multivibrators and an ExclusiveOR gate to detect the missing

Data Accepted pulse. When a key is pressed, the resulting Data Ready strobe fires IC la and IClb. ICla is "set" for the longest time you will allow before signaling a missing Data Accepted pulse (perhaps 50 ms). IClb is set a few microseconds to a few milliseconds longer than la (it only has to be 50 ns longer).

When these two one-shots fire, they open a timing window for the Data Accepted strobe. If it is received within the period allowed by la, then la and lb are reset (no beep). If, however, no Data Accepted pulse is received, la will time-out before lb. The opposite logic outputs of the two one-shots are then sensed

IC

Number

Type

+ 5V

GND

IC1

74LS123

16

8

IC2

74LS86

14

7

1C3

74LS123

16

8

by an Exclusive-OR, IC 2, which fires IC 3. IC3 is a oneshot set for 200 ms and connected to a beeper. As long as

the Data Accepted pulse is received within 50 milliseconds, you should never hear It.... Steve

In "Ask BYTE," Steve Ciarcia answers questions on any area of microcomputing. Tlie most representative questions received each month will be answered and published. Do you have a nagging problem? Send your inquiry to;

Ask BYTE

do Steve Ciarcia

POB 582

Glastonbury CT 06033 If you are a subscriber to The Source, send your questions by elearonic mail or chat with Steve (TCE3I7) direaly. Due to the high volume of ihquiries, personal replies cannot be given. Be sure to include "Ask BYTE" in the address.

Now! An

Coupler for $125.

The Omnitec Model 715 (originate only) has the necessary features, needed to expand any business or home computer systems capability: 0-450 baud data rate, RS232 compatibility and carrier detect at a low factory-direct price of $125. Or, select the Model 770 at $179.00 for originate or answer communications. ^ ^ Both models carry a one year warranty

®OMNITEC DATA 2405 South 20lh Street • PlioenJx, Arizona 85034

PRICES INCLUDE SHIPPING & HANDLING WHEN PRE-PAID

V

Circle 300 on inquiry card.

circle 290 on Inquiry card.

Circle 398 on Inquiry card.

ptpODqrq

Modem Kit

300 Baud Acoustic Coupler

$69.00

Includes; Power Supply Speakers

Printed Circuit Board All Integrated Circuits,

Resistors & Capacitors Instruction and Trouble

Shooting Book

Order Direct or Call for the Location

of the Closest Dealer

Add $4.00 for Shipping Charge. Ohio Residents add 6.5% for Sales Tax

I

MASTERCHAROE

OHK> Dqrq pRODUcn coqpoRsnon

14600 Dalrott AvBHUB • Clavalanil, Ohio 44107 • (218) 221-9000

Allow 6 WBOks for Delivery

I I

I J

NEW TARBELL S-100 CPU/IO BOARD

Z-80'" will run at 2 or 4 Mhz

2 RS-232 Serial I/O ports

Powerful Memory Management

Programmable Timer

Full masked priority interrupts

Has everything needed for MP/M"

6 month full warranty

Z-80 is a trademark of Zilog Inc.

MP/M is a trademark of Digital Research

950 Dovlen Place, Suite B Carson, CA 90746 Phone (213) 538-4251

META TECHNOLOGIES

26111 Brush Avenue. Euclid Ohio 44132 CALL TOLL FREE 1-800-321-3552 TO ORDER

IN OHIO, call (216) 289-7500 (COLLECT)

MICROPARAPHERNAUA

DISKETTES (box of ten)

5%" PLAIN JANETM $21.95

PLAIN JANETM rjf,/^/ $25.95

i" DATALIFETM |V|D 525-01 .. $26.95 8" DATALIFE™ FD34-8000 .... $43.95

NEWDOS by APPARAT

NEWDOS . to

NEWD0S/8C UPGRADE CALL

NEWDOS • with ALL UTILITIES

35-track $69.95

40-track ... $79.95

BOOKS

TRS-SQTM DISK

AND OTHER MYSTERIES .. $19.95 MICROSOFTTM BASIC DECODED $29.95 1001 THINGS TO DO WITH YOUR

PERSONAL COMPUTER ... $ 7.95

80-20=12995

THE ORIGINAL NEWDOS/80

WITH MTC QUE CARD

★ SPECIAL PRICE ★ SAVE $20 $129.95

Apparat's long-awiiited successor to NEWDOS-H Is here! This is not an enhanced ver^ sion o( NEWDOS. but a completely new product. Simplilied DOS commands can be instantly executed Irom BASIC, even within a program, without disturbing the resident code. System options, such as password protection, number and type o( disk drives, BREAK key enable/disable and lowercase modification recognition, can be quickly easily changed. Five new random-access file types allow record lengths of up to 4096 bytes, and no FIELDing! A powerful CHAIN facility allows keyboard INPUTs to be read Irom a disk file. An improved RENUMBER facility permits groups of statements to be relocated within program code. Diskettes may even be designated as RUN-ONLY Features all NEWDOS-t- utilities (SUPERZAP 3.0. etc.) and much more! One MTC technical staff member said having NEWDOS/80 is "better than sex" (you'll have to judge for yourself!). Includes 180-page instruction manual and MTC QUE card.

NEWDOS/80 ft SPECIALS $129.95

MTC QUE Card only S 7.50

CALL REGARDING OUR NEWDOS-t- UPGRADE PRICING

TMb 80 n .1 t'jai-mark a( the ».i(lLO Slutk Diuiiion ol Tandy Corporation DATALIFE is a trjdemjik o( VERBATIM PLAIN JANE. AIDS 1. AIDS III. CALCS III. CALCSIV, MERGE 111 are

tradtm^rki ol UTC 1981 bf Metatechnoloeies Corporation, Inc.

MOST ORDERS SHIPPED WITHIN ONE BUSINESS DAY Products damaged in transit will t>e exchanged.

PRICES IN EFFECT ^ May 1, 1981 THRU

May 31. 1981. Prices, Specifications, and Offerings subject to change without notice, ^ 8105 J

WE ACCEPT

• VISA

. MASTER CHARGE . CHECKS

• MONEY ORDERS

• CO D.

■Add S3.00 lor shipping & handling

'$3.00 EXTRA lor C.O.D. •Ohio residents atM 6>/i% sales tax.

CALL FOR INFORMATION ON OTHER PRODUCTS

Circle 235 on Inquiry card.

BYTE May 1981 393

System Log

Software Received

CNOSYICS

JDij gnsstips 11 is SuperSoft's expanded Diagnostic package.

Oia nostic II builds upon the highly acclaimed Diagnostics I. It will test eacn of the five areas of your system:

Memory Terminal Printer CPU Disk

Every test is expanded.

Every test Is "submit"-able. A "submit" file is included in the package v\/hlch "chains" together the programs in Diagnostics II, achieving an effective acceptance test. All output can be directed to a log file for unattended operation, for example over night testing. Terminal test is now generalized for most crt terminals. A quick-test has been added for quick verification of the working of the system.

The memory test is the best one we have encountered. It has new features,

including:

• default to the size of the CP/I^ Transient Program Area (TPA)

• printout of a graphic memory map • burn in test

• bank selection option • memory speed test Diagnostics-ll still includes the only CPU test for 8080/8085/Z80.

A Spinwrlter/Diablo/Qume test has been added, which tests for the positioning and control features of the Spinwriter/Dlablo/Qume as well as its ASCII printing features. (Serial Interface only)

And, as with all SuperSoft products, a complete online HELP system and user manual is inciuded.

Price: $100.00 (manual only): $15.00

Requires: 32K CP/M

CP/M Formats: 8" soft sectored, 5" Northstar, 5" Micropolis Mod II, Vector MZ, Superbrain DD/QD

SuperSoft

All Orders and General Information: SUPERSOFT ASSOCIATES P.O. BOX 1628 CHAMPAIGN, IL 61820 (217)359-2112

Technical Hot Line: (217) 359-2691 (answered only when technician is available)

CP/M REGISTERED TRADEMARK DiGTAL RESEARCH

Apple

Astro-Scope, horoscope for the Apple II. Floppy disk, $30. Astro-Graphics Services Inc, FOB 28, Orleans MA

02653.

E, Applesoft editing utility for the Apple II Plus. Cassette, $14.95. Apollo Software Company, 318 Harvard St, Suite 10, Brookline MA 02146.

Electronics I, electronicsdesign application programs for the Apple II. Floppy disk, $29.95. Howard W Sams & Company Inc, 4300 W 62nd St, FOB 558, Indianapolis IN 46268.

Electronics II, electronicsdesign programs for the Apple II. Floppy disk, $29.95. Howrard W Sams & Company Inc (see above).

Electronics III, electronicsdesign programs for the Apple II. Floppy disk, $29.95. Howard W Sams & Company Inc (see above).

Masterdos, disk customizing programs for the Apple II Flus. Floppy disk, $29.95. Masterworks Software Inc FOB 7000-285, Rolling Hills Estates CA 90274.

Micro-Painter, color drawing program for the Apple II. Floppy disk, $34.95. Datasoft Inc, 16606 Schoenborn St, Sepulveda CA 91343.

1981 Tax Preparer, IRS tax-preparation aid for the Apple II. Floppy disk, $99. Howard Software Services, 7722 Hosford Ave, Los Angeles CA 90045.

Reversal, graphics strategy game for the Apple II (plays Othello, a trademark of CBS Inc). Floppy disk, $34.95. Hayden Book CompcUiy Inc, 50 Essex St, Rochelle Park NJ 07662.

Sex-O-Scope, horoscope for the Apple II. Floppy disk, $30. Astro-Graphics Services Inc (see above).

TRS-80

Active Filter Design,

May 1981 © BYTE Publiutioiu Inc

Circle 373 on Inquiry card.

Circle 278 on Inquiry card,

The WORKSHEET Problem-Solving Language

Want to play "What-if"? Want to do Real Estate Analysis. Family Budgeting, Taxes. Company Cash Flow; want to simulate complex and interrelated processes? WORKSHEET is a powerful language designed for the purpose of writing programs to solve these and all other problems that involve a row-column "spreadsheet". Even novice programmers are solving complicated problems on the first day!

WORKSHEET is not a hybrid text editor or a toy. It is a complete, self-documenting model-building system. List the assumptions that went into your budget with the SHOWFIL program—even the boss will understand!

Change the assumptions, the relationships, or the data, and produce a new spreadsheet, neatly captioned, in minutes.

Model too big to fit on a single page? Format it dynamically— one page of 12 (or any number) columns, or 2 pages of 6 columns, or whatever tells your story best.

Conduiona\ evaluation of a variable? Reference to variables in different rows, several columns back? No problem!

Sample models include portfolio valuation, real estate evaluation, iterative solution of a Diophantine equation, family budget, product profit based on exponentially damped growth of sales.

Use it for tough, professional jobssvstem that can handle them!

it's the only CP/ M modeling

Requires 4XK CP M system and Microsoft Basic . C Basic or North Star Basic running under CP, M with Matchmaker 11.

WORKSHEET Language disk (5" or 8" CP; M) SI99.95

(specifv version) 80-Page Manual only '. $ 19.95

The SoHo Group 140 Thompson St., Suite 4-B New York, NY 10012

DIGITAL DATA RECORDER MODEL CC-9B

For five years now, the CC series recorders have been the industry NRZ Asynchronous recorder standard. Now the D series sets a new standard in stability and reliabihty with its tachometer feedback LC stabilized motor circuit.

4800 or 9600 Baud (3" or 6" per second)

lO'' Error Rate

RS232 or TTL

In and Out RTS motor start CTS Data start DB 25 or special

connector optional 110/220 - 50/60 Hz Wow & Flutter±.3% Speed Stability (long

term) + .l%

DCl Model Price $275.00 DC2 Model Price $285.00

NATIONAL MULTIPLEX CORPORATION

260 Lackland Drive East Middlesex, New Jersey 08846 Tel. (201) 356-9200 TWX 710-997-9530

A. B. C.

26xl4'/2x8 26x24x18 24x24x14

$39.95 $59.95 69.95

A. The lectern for your Apple is an Ideal desk-top unit.

B. The CRT flat top has a multiple number of uses - Ideal

for large CRT w/ith storage shelf.

C. The printer secretary is designed for several different printers - with a shelf for paper storage, slotted top and back for paper feed.

Exteriors are walnut grain Formica. To order, send check or money order to:

Data Design

P.O. Box 1252 Kissimmee, FL 32741

Add $6.00 for freight & handling - FL res. add 4% tax.

MICROSTAT NOW AVAILABLE FOR CBASIC2*

MICROSTAT is the statistics package for microcomputers, and is proving itself to users around the world, including:

Stanford, Harvard, Johnson & Johnson, Duke, University of Washington, UCLA, Lockheed, University of Pennsylvania, Oklahoma Stale, U.S. Geological Survey, Monsanto, University of Toronto, Sweden's National Central Bureau of Statistics, Utah State, Butler University, SUNY, Van Camps, Texas A&M, University of Wisconsin

and a growing list of other organizations. MICROSTAT's Data Management Suhsystem (DMS) makes creating your own data files easy and includes numerous editing and transformation capabilities. Files produced hy DMS can then be used to generate statistics in all common statistical areas (e.g., descriptive statistics, ANOVA, correlation, multiple regression, probability and hypothesis tests, nonparametrics and others) plus some not so common ones. Whether pure reserch or industrial quality control, MICROSTAT is the statistics package for you.

MICROSTAT sells for $250.00 and is supplied on 8" SD or 5'/<" (North Star) disks. The user's manual sells for $18.00 and includes sample data and printouts. Please specify version when ordering. Foreign inquiries, please write directly'to us.

ECOSOFT

P.O. Box 68602 Indianapolis, IN 46268 (317) 283-8883

* CBASIC2 is a registered trade mark of Digital Research.

Circle 143 on inquiry card.

Circle 111 on Inquiry card.

BYTE May 1981 395

The ZVX4 MEGABYTER is for the APPLE II user who wants to DOUBLE file size, expand the capability of existing business software, and make other SERIOUS applications more viable.

Now you can have compatibility with IBM, INTEL, CP/M*, Z80 Softcard*, UCSD Pascal, and others.

Look what the MEGABYTER dual density 8" floppy disk controller, with its LSI circuitry and reliable industry standard IBM 3740 format, means to you:

INCREASED STORAGE

• . Increase online storage to 2 Mega bytes

• Double your maximtun accounts and file size

• Add high capacity efficient hard disk backup

• Control up to 4 Shugart SA800/SA850 drives

IMPROVED COMPATIBILITY

• Operate APPLE DOS 3.1/3.2/3.3, mini disks

• Preserve existing software investment

• Interchange data with other computers

SIMPLIFIED OPERATION

• Reduce disk handling and I/O slot usage

• Gain automatic single/double density operation

• Change to double sided drives with one switch

Available at your Apple dealer. Call or write today!!

SORRENTO VALLEY ASSOCIATES

1722 SORRENTO VALLEY ROAD SAN DIEGO, CA 92121 |714.| 452-0101

• CP/M trademark of Digital Research, Inc. Z80 Softcard trademark of MiGrosoi^,^|ir

^-\ \ S

>SVA>i

Software Received.

electronic-design program for the TRS-80. Cassette, $24.95. Howard W Sams & Company Inc, 4300 W 62nd St, FOB 558, Indianapolis IN 46268.

Arcade-80, arcade-like graphics game for the TRS-80. Floppy disk, $24.95.

Datasoft Inc, 16606 Schoenborn St, Sepulveda CA 91343.

Cosmic Fighter, graphics arcade game for the TRS-80. Cassette, $17.95. Big Five Software, FOB 9078, Van Nuys CA 91409.

Descriptive Statistics & Regression Analysis, statistics package for the TRS-80. Cassette, $24.95. Howard W Sams & Company Inc (see above).

Football Classics, graphics strategy game for the TRS-80. Floppy disk, $24.95. Datasoft Inc (see above).

Genealogy, genealogy program for the TRS-80 Model II. Eight-inch floppy disk, $250. John J Armstrong, 3700 Whispering Pine Rd #47B, Mobile AL 36608.

lago, graphics strategy game for the TRS-80 (plays Othello, a trademark of CBS Inc). Cassette, $19.95. Datasoft Inc (see above).

Plotting Graphs for Line Printer, graphing program for the TRS-80. Cassette, $24.95. Howard W Sams & Company Inc (see above).

Plotting Graphs for Video

Display, graphing program for the TRS-80. Cassette, $24.95. Howard W Sams & Company Inc (see above).

Real-Estate, real-estate program for the TRS-80 Focket Computer. Cassette, $24.95. Radio Shack, 1300 One Tandy Center, Ft Worth TX 76102.

Other Computers

Atari Character Generator, graphics utility for the Atari 400 and 800. Cassette, $15.95. Datasoft Inc, 16606 Schoenbom St, Sepulveda CA 91343.

C Compiler Version 1.4, programming language for the CP/M system. Eight-inch floppy disk, $145. B D Software, Cambridge MA 02139 (distributed by Lifeboat Associates, 1651 Third Ave, New York NY 10028).

Chest of Classics, collection of games for the Sinclair ZX80. Cassette, $9.95. LamoLem Labs, FOB 2382, La Jolla CA 92038.

MINCE Version 2.4, word processor for the CP/M system. Eight-inch floppy disk, $125. Mark of the Unicom, FOB 423, Arlington MA 02174.

Telelink I, terminal program for the Atari 400 and 800. Program cartridge, $19.95. Atari Inc, FOB 427, Sunnyvale CA 94086. ■

This is a list of software packages tliat have been received by BYTE Publications during the past month. The list is correct to the best of our knowledge, but it is not meant to be a full description of the product or the forms in which the product is available. In particular, some packages may be sold for several machines or in both cassette and floppy-disk format; the product listed here is the version received by BYTE Publications.

This is an all-inclusive list that makes no comment on the quality or usefulness of the software listed. U/e regret that we cannot review every software package we receive. Instead, this list is meant to be a monthly acknowledgment of these packages and the companies that sent them. Companies sending software packages must include the suggested list price of the packages and (where appropriate) the alternate forms in which they are available.

396 May 1981 © BYTE Publicabons Inc

Circle 380 on inquiry card.

Circle 355 on inquiry card.

liiiiiftiiir.

■'SiiSifiiPi^''''''"'

Boards forS-100 BUS

from S.C. Digital

■•CPUI-Z80"

Advanced Z80A based CPU beard S219 Assembled and Tested S149 Kit *(le>s itibmipt)

Features: Model CPUI-Z80

• 2/4 Mhz SW selectable. * Built in 8 Prioritized Vectored Interrupts with 8 passible levels of Nested Interrupts using powerful Mode 2 of Z80, all done in Hardware, expandable with external ckt. * Vector Jump on RESET, in 4K increments. * SuppsitS 2K of EPROM (not supplied), DMA, dynarmic RAM refresh . . . many more. 'Kit comes with all parts except chips connected to bitemipts.

"INTERFACE: 1"

I/O, Memory Interface Board

S229 Assembled and Tested SI69 Kit

Features: Model 3SPC

• 3 Serial w RS232C or 20ma Current Loop, 1 Parallel. • 4K of EPROM/ROM and 4K of RAM (ROM/RAM not supplied). • Built In Kansas City Standard Cassette Interface usable to 1200 Baud. • Generates all popular baud rates op to 19.2K baud. Including 1106134.5. • SW satiable Address, Baud Rates, Ports.

"UNISELECT" 16K Static RAM with universal Banlc Select

Model 16KUS $235 A Er T, with 200 nsec memory chips.

All boanls meet IEEE-S100 standards. Fully socketed, solder masks, gold contacts, and guaranteed for one full year. Kit guaranteed parts, only.

Delivery: from stock to 72 hours. Ordering: You may call for M.C., Visa or C.0.0. orders. (AddS4.00 for CO.D.) Personal checks ok, but M.O. speeds shipment. Takes? to 15 days to clear personal checks before shipping.

Undamaged boards can be returned within 10 days for full refunds. Illinois residents add 5Va%

" ' ^ O.EM. PRICING AVAIUBLE, DEALER INQUIRY INVITED f>I P.O. Box 906 Plione: • V# . 19' Aurora, IL 60507 (312) 897-7749

Turn your Selectric into a word processing system for

only rm^^^,

S599I PRODUCTS

^^^^^^ Air.n.^ta Boiile

^ESCON

' 'I PRODUCTS.INC.

12919 Alcosta Boulevard San Ramon, CA 94583 Call Toll Free: 800-227-2148

DEALERS !!!

Tired of losing sales

because your source is out

of stock or they just don't carry the product . . .

NOT ANY MORE !

with

CA AZ

Computers West

415/944-9431 602/949-1117

.easing Program Available

800-323-1780 NCE's HOTLINE FOR SAVINGS

• Ribbons for. Diablo, Qume, IBI^, Wang, NEC, All Data Printers and Typewriters.

• Printwheels, Elements and Thimbles.

• IMagnetic Media: Floppy cilsks. mini-floppy, Tape, Packs and Cassettes.

• Disc storage systems, Quietizers, Anti-static mats, inic roils and much more.

• Terminals and accessories.

• TO ORDER •

Ptione orders invited, using credit cards. Or send check, castiiers check or money order that draws on a U.S. bank. Please add 3% (S5.00 fulinimum) for fiandling. shipping and insurance. Illinois residents add b'AVi sales tax. Iltall order pricing only. Catalog mailed upon request.

WARRANTY

So great is NCE'S confidence in its Thoroughbred Series Diskettes, that each Disk iS guaranteed for 10mm passes and for 2 full years against manufacturing defects. Send for full Warranty information.

REIMARKABLE NCE'S THOROUGHBRED SERIES, DISKETTES

A New Classic on the Track!

• 100% Certified - EACH AND EVERY DISKETTE,

• Precise, special burnishing,

• Packaged in crushproof plastic storage boxes.

• All mini disks Include hubrlngs attached.

• Warranfeed for 10 mm passes and 2 full years.

• Superior to disks selling for twice ttie price.

• Quite simply, THE BEST DISK EVER BUILT.

Partial Selection

5'A" (SS-SD) 8" (SS-SD) 8" (SS-DD) 8" (DS-DD)

BoxodO 29.95 32.50 50.00 52.50

Hunmhttmnoroughbreds" Satisfaction Guaranteed

NCE Supply Corp. WW 19S Kehoe Blvd. BIdg. 5 tTT. Carol Stream, IL 60187 lOd

Phone: 800-323-1780 Toll Free '312-682-0001 Within Illinois TELEX 724389 ATTNNCE •Distribution Worldwide

Circle 96 on inquiry card.

Circle 279 on inquiry card.

BYTE May 19n 397

IS BASIC TOO SLXDW?

OSBORNE McGraw-Hill's Assembly Language books help you speed up your programs

fie.99a

$16.99 o $79.99^

Osborne/McGraW'Hill simplifies assembly language programming. You needn't know anything about assembly language to use our ALP series. Each book is a straighforws^^lf-teaching ■ textbook that is concise and easy to understan^^Hteok explains assembly language programming,; describes the 1unctiori:ipB||fcto^st.ruclured programming, and presents many fully debugged i^|^|^^ramming

liiii f3M\

MM UMtaaim

i'.lli!':!!:!

■

BRAND NEW!

6809 Assembly Language Programming

While everyone's been talking about the new 16-bit microprocessors, the 6809 has emerged as the hottest new device. This book will help you understand why. It offers you everything you need to program Motorola's 6809 microprocessor in assembly language and allow you to take full advantage of the 6809's unique design.

□ #35-7 680 pp. $16.99

Make check payable to: ff^ Osborne/McGraw-Hill 630 Bancroft Way, Berkeley, CA 94710 Dept B1S

Name

Phone Orders: (415) 548-2805 Toll Free: 800-227-2895

Address ^ ,

City/Stale/Zlp '.

PlU8n.75/item4thclass DSLas/itemUPS □$2.50/)$efnAfrMail D$10,00/ltemOverseaa (California residents add applicable tax.) □ Please send m yarn free catalog.

Total amount enclosed $ or charge my □ Visa O Masteroharge

■Card # Expiration Date .

Books Received

AIM-65, Laboratory Manual and Study Guide, Leo J Scan!on. Somerset NJ: John Wiley & Sons Inc, 1981; 21.5 by 28 cm, 179 pages; softcover, ISBN 0-471-06488-2, $7.95.

APL-Stat, James B Ramsey and Gerald L Musgrave. Belmont CA: Lifetime Learning Publications, 1981; 21.5 by 28 cm, 356 pages; softcover, ISBN 0-534-97985-8, $14.95. Solutions manual for above $3.95.

Apple Machine Language, Don Inman and Kurt Inman. Reston VA: Reston Publishing Company Inc, 1981; 16 by 24 cm, 296 pages; hardcover, ISBN 0-8359-0231-5, $9.95.

The Calculator Afloat, Captain Henry H Shufeldt, USNR (retired) and" Kenneth E Newcomer. Annapolis MD: Naval Institute Press, 1980; 16 by 23.5 cm, 225 pages; hardcover, ISBN 0-87021-116-1, $16.95.

Computers in Society, Donald H Sanders. New York: McGraw-Hill Book Company, 1981; 19.5 by 24 cm, 622 pages; hardcover, ISBN 0-07-054672-X, $16.95.

Disassembled Handbook for TRS'80, Volume IH, Robert M Richardson. Chautauqua NY: Richcraft Engineering Ltd, 1981; 24 by 28 cm, 239 pages; softcover, ISBN-none, $18.

Electric Machines and Transformers, Leonard R Anderson. Reston VA: Reston Publishing Company Inc, 1981; 18.5 by 24 cm, 305 pages; hardcover, ISBN 0-8359-1615-4, $18.95.

Experimentation with Microprocessor Applications, Thomas W Davis. Reston VA: Reston Publishing Company Inc, 1981; 17.5 by 23.5 cm, 237 pages; softcover, ISBN 0-8359-1812-2, $9.95.

Fifty BASIC Exercises, ] P Lamoitier. Berkeley CA: Sybex, 1981; 18 by 23 cm, 253 pages; softcover, ISBN 0-89588-056-3, $12.95.

FORTRAN IV, Second Edition, J Friedmann, P

398 May 1981 © BYTE Publications Inc

Circle 305 on Inquiry card.

S-100 GRAPHICS

Unretouched photograph

• 512 X 640 matrix available in black and white, gray tones, or color

• Bit mapped design for high speed performance

• Easily expandable from basic ^lack and white by adding memory planes.

• Variety of software: graphical BASIC, Tektronix emulator, printer drivers, character editor

• Compatible monitors and printers available.

r\ CAIWBRIDGE DEVELOPMENT

( \ LABORATORY

V J 36 Pleasant street, Watertown, MA 02172

^ ^ (617)926-0869

Circle 71 on inquiry card.

SINGLE BOARD TECHNOLOGY

Basic system with: 600K bytes $2995.

• 1.2 megabytes $3995.

• 2.4 megabytes $4995.

Suggested list price.

A Z80ACPU combined with the CP/M® operating system opens new vistas to software availability for eight-bit micros. FORTRAN, COBOL. BASIC, APL, PL/1 and Pascal are available now to accommodate today's scientific, educational, sophisticated small business and personal system users.

• 4MHzZ80ACPU

• CP/M 2 operating system

• 64K 200ns main memory

• 6K 300ns video memory

• 8-inch dual floppy drives

• color video text & graphics

• sound generator

• 2-serial ports

• 2-parallel ports

• 4-counter/timers

Quantity discounts are available. OEM inquiries are invited. Please contact:

COLONIAL DATA SERVICES CORP.

105 Sanford St., Hamden, Connecticut 06514

(203)288-2524 EAST COAST • (415)957-9195 WEST COAST ®CP/M Is a registered trademark of Digital Research, Inc.

ANNOUNCING JHE 256K BYTE RAM BOARD

The company that was first with the 8088 on the SI 00 bus, now introduces the LDP 256K RAM board. The board Is presently configured as a 64K Dynamic board with upgrade kits available in August to a full 256K Bytes.

Buy the RAM with the future. Why settle for anything less! The RAM features the following: parity for error control, meets all IEEE 696 specifications, 8/16 bit operations, no wait states with a 5 MHz 8088.

Introductory 64K price of $695 until June 15th after which It will be $795.

LDP88 — The first, the best and the least expensive 8088 CPU

available for the S100 bus. LDP72 — Advanced floppy disk controller: single and double density operation, single or double sided drives, 5 1/4" or 8" drives. LDP1 — For the person who prefers the complete package, the LDP1 has 64K of RAM, 8088 CPU, 8" floppy disk with controller, mainframe and power supply with either 86-DOS or CP/M-86.

PRICES

KIT

ASSEMBLED & TESTED

LDP64 K RAM

n/a

$695.00

LDP88

$349.95

399.99

LDP72

219.95

274.95

S100 Prototype Board

29.95

86-DOS

19500

CP/M-86

250.00

Micro Soft Basic 86

500.00

86-DOS required

350.00

with LDP1 and 86-DOS

250.00

CP/M-86 required

Rev. A LDP88's while they last

275.00

LDP1 with CP/M-86 or 86-DOS

3499.99

LOMAS DATA PRODUCTS

11 Cross Street Westborough, MA 01581 Telephone (617) 366^335

:rjd(>m*rk of Seville Computer Product!

LINE VOLTAGE TRANSIENT CUPPING

Features Parallel Operation 5000 Hits/Second

PROTECTS:

•Computers

• Micro-Computer Systems •Word Processors •Cash Registers

• Power Supplies

MARC

INDUSTRIES, INC.

PROTECTS AGAINST:

•Higti Energy Voltage Transients •On-Off Svi'itching

• Ligtitning Induced Transients

• Inrush of On/Off Power

a78F

TRANSIENT VOLTAGE SURGE SUPFKESSOR USTEO

Dealer Inquiries Invited.

7133 Rutherford Rd. Baltimore, Md. 21207

, (301)298-3130 800-638-9098 ^

Circle 222 on inquiry card.

Circle 138 on Inquiry card.

Sm May 1981 399

Circle 93 on inquiry card.

ATTENTION GOVERNMENT D P USERS AND PURCHASERS

We represent many fine micro products and manufacturers on the GSA Schedule, including

Apple, Cromemco

and Computer Corporation of America

Purchasing from the Schedule will save you the time consumed by the bid process. Products shipped throughout the United States and world-wide. Visit or write any of our stores for more information or to receive our catalogue of products represented.

Computers.

the dependable stoie

257 West Street, Annapolis, MD 21401 - (301) 268-6505 13A Allegheny Avenue, Towson, MD 21204 - (301) 296-0520 9330 Georgia Avenue, Silver Spring, MD 20910 - (301) 588-3748 or Call (301) 268-5801

Career Opportunities Available *An Equal Opportunity Employer

HOBBYISTS!

EPROM PROGRAMMING

for as low as $9.95

LTSI will reproduce your program on an EPROM supplied by us

• Input from Master EPROM, Truth Table, or Paper Tape In standard format

• Output to 2708, 2716, 2732, 2564 U.S. manufactured EPROM

TERMS:

• Checks or money orders (do not send cash)

• Allow up to 4 weeks for delivery

• Illinois residents add 6% sales tax.

Output to

INPUT

FROM:

Ctiarge lor each

EPROM

Master EPROM

Non-returnable extra prograinnied

device

or Paper Tape

Truth Table

EPROM

2708

$ 9.95

$ 24.95

$ 8.00

2716

$20.95

$ 50.95

$15.00

2732

$35.95

$ 80.95

$30.00

2564

$95.95

$155.95

$90.00

Blank TRUTH TABLE entry forms available upon request

LOGIC TECHNOLOGY SERVICES, INC.

2400 E. Oakton

Arlington Heights, IL 60005/312-364-4670

Please reproduce the enclosed (MASTER EPROM, PAPER TAPE, Non-returnable TRUTH TABLE) program on a (2708, 2716, 2732, 2564) EPROM. You will find enclosed my checl< or money order for $

# of EPROMS requested

NAME

ADDRESS

CITV/STATF/7IP

PHONE

SIGNATURE.

Greenberg, and A Hoffberg. Somerset NJ: John Wiley & Sons Inc, 1981; 17 by 25.5 cm, 499 pages; softcover, ISBN 0-471-07771-2, $10.95.

Fundamental Structures of Computer Science, W A Wulf, M Shaw, P N Hilfinger and L Flon. Reading MA: Addison-Wesley Publishing, 1981; 17 by 24.5 cm, 621 pages; hardcover, ISBN 0-201-08725-1, $21.95.

H-8 Programming for Beginners, Don Inman and Bob Albrecht. Portland OR: Dilithium Press, 1980; 13.5 by 21.5 cm, 194 pages; softcover, ISBN 0-918398-17-7, $8.95.

LISP, P H Winston and B K P Horn. Reading MA: Addison-Wesley Publishing, 1981; 16 by 23.5 cm, 430 pages; softcover, ISBN 0-201-08329-9, $13.95.

Multinational Computer Nets, Richard H Veith. Lexington MA: Lexington Books, 1981; 16.5 by 23.5 cm, 133 pages; hardcover, ISBN 0-669-04092-4, $18.95.

Problem-Solving and Structured Programming in Pascal, Elliot B Koffman. Reading MA: AddisonWesley Publishing, 1981; 16 by 23 cm, 483 pages; softcover, ISBN 0-201-03893-5, $13.95.

Programmer's Guide to LISP, Ken Tracton. Blue Ridge Summit PA: Tab Books Inc, 1980; 13 by 21 cm, 210 pages, softcover, ISBN 0-8306-1045-6, $6.95; hardcover. ISBN 0-8306-9761-6, $10.95.

Protocols & Techniques for Data Communication Networks, Franklin F Kuo, editor. Englewood Cliffs NJ: Prentice-Hall Inc, 1981; 18.5 by 24 cm, 468 pages; hardcover, ISBN 0-13-731729-8, $29.95.

The Small Computer in Small Business, A Guide to Selection and Use, Brian R Smith. Brattleboro VT: Stephen Greene Press, 198J; 16 by 23.5 cm, 143 pages; hardcover, ISBN &«8»O407-3, $12.50.

Small Computers for the Small Businessman, Nicholas Rosa and Sharon Rosa. Portland OR: Dilithium Press, 1980; 14 by 21 cm, 301

400 May 1981 © BYTE Publkatioiu Inc

Circle 220 on inquiry card.

Circle 149 on inquiry card.

Circle 268 on inquiry card.

DISK DRIVE WOES? PRINTER INTERACTION? MEMORY LOSS? ERRATIC OPERATION?

Don't

Blame The Software!

Power Line Spikes, Surges & Hash could be the culprit! Floppies, printers, memory & processor often interact! Our unique ISOLATORS eliminate equipment interaction AND curb damaging Power Line Spikes, Surges and Hash.

• ISOLATOR (ISO-1) 3 filter Isolated S prong sockets; integral Surge/Spike Suppression; 1875 W Maximum load, 1 KW load any socket $62.95

• ISOLATOR (ISO-2) 2 filter Isolated S prong socket banks; (6 sockets total); integral Spike/Surge Suppression; 1875 W Max load, 1 KW either bank $62.95

• SUPER ISOLATOR (ISO-3), similar to ISO-1 except double filtering & Suppression $94.95

• ISOLATOR (ISO-4), similar to ISO-1 except unit lias 6 Individually filtered sockets $106.95

• ISOLATOR (iSO-5), similar to ISO-2 except unit has 3 socket banks, 9 sockets total $87.95

• CIRCUIT BREAKER, any model (add-CB) Add $ 8.00

• CKTBRKR/SWITCH/PiLOT(-CBS) Add $16.00

Master-Charge, Visa, American Express Order Toll Free 1-800-225-4876 (except AK, HI, MA, PR & Canada)

Electronic Specialists, Inc.

171 South Main Street. Natick. Mass. 07760

Teciinical & Non-800: 1-617-655-1532

DECLSMl Components

Dependable service at discount prices

Domestic and Export

mini

Computer Suppliers,inc.

25 Chatham Rd., Summit, N.J. 07901 Since 1973

(201) 277-6150 Telex 13-6476

THE FORTH SOURCE

TM

Specializing language.

in the FORTH

Printed Material

Using FORTH, Manual $25.00

PDP-11 User's Guide 20.00

Systems Guide to fig-FORTH 20.00

CalTech FORTH Manual 11.00

TinyPASCAL in fig-FORTH 10.00

fig-FORTH Cross Compiler 30.00 PLUS many source listings

Machine Readable H89 & Z89 Disks & Documentation

Operating System, with tutorial $135.00

fig-FORTH, CP/M, with tutorial 135.00

TinyPASCAL, with source 75.00

fig-FORTH, CP/M 65.00

Write for complete FORTH List.

MOUNTAIN VIEW PRESS PO BOX 4656 Mt. View, OA 94040

Save on Calculators

$325.00 495.00 B40.00 215.00 385.00 250.00

Model

New HP-41CV Z.2K bytes, 4 mem. modules

built-in, slanted keyboard System One, HPAICV & Card Reader System Two, HP41CV-Card Reader & Printer Card reader for 41 C/4tCV Primer for41C/41CV HP-41C new price

Quad Ram to upgrade the KP41C to 2.2K

bytes leaving3ports...Plugsintothe41C 95.00

Oplicai Wandfor41C/41CV

Memory Modules for41C/41CV HP-34C Sciemific HP-38C Bus./R.E. HP-33C Scientific HP-32EAdv, Scientific HP-37EBLS. Calc. HP-67 Programmable Sci. HP-97 Prog. Printer Sci. HP-85 Computer

New HP-83 Computer, similar to HP-85 without printer & cassette

$269.95 394.95

HEWLETT PACKARD

Olympic Sales is an HP authorized dealer.

"C" stands for continuous memory.

One year guarantee by HP on all calcs, 90 days on computers. All unite complete.

BnpplG computer

APPLE II and APPLE III

Huge inventory of Apple II computers.

16K-32K-48K. Disk drives, monitors, 60

column card. Dow Jones & Quote

Reporter.

Pascal-Fortran—DOS 3.3, etc. You name iL..wB'vB got It at super low. prices,

Immediate delivery on Apple III computers 96K and IKK systems. Call usi

Computers at unbeatable prices

Texas Instruments

99/4 console computer

S449.95

TI-5230 printer (was S495)

169.95

TI.59

199.95

PC IDOC

149.95

EPSON MX80 printer

499.95

Atari 8G0 I6K cnsle compu

759.95

Ateri TV Game

144.95

Mattel Intel TV Game

239.95

Mattel Race Horse Anivzr

S9.9S

Centronics printer PI for

Apple & Radio Shack

computers. Was 495.D0

189.95

Call us fDr best prices

Centronics printers 17 models

Novation models CD-CAT/C^T 7 models

Shugart disk driy^ 8 models

Paper Tiger printers 5 models

Hazeltlne videp display terminals 7 models

Diablo printers 4 models

DEC VTIOO S VT103 2 models

RCA VideoDisc Smoo player5469.95 (Many motion picture discs available) Call us SCM Typewriters • 320 models Seiko watches • Royal * Victor • Canon • Sharp • Casio and mora.

Prices f.o.b. LA. f^flinimum freight & handling charge—$4.95. In CA, add 6% sales tax. Goods subject to availabilitv. We'll beat any advertised price if competitor has goods on hand. = CallMon-Sat7AM-6PM.

Outside CA, toll free 800-421-8045 Inside CA, toll free 800-252-2153

OLvmpic SAies comPAm. inc.

216 Soulh Ollom Ave - P.O. Box 74545 • Los Anseles, CA 90D04 ■ (213) 381-3911 Drder Desk (213) 739-1130 • Customer Senice (213) 739-1100 • TelB« 67-3477

Circle 275 on Inquiry card.

Circle 294 on inquiry card.

BYTE May 1981 401

Circle 421 on inquiry card.

Leverage Brings the Power of "C" to Today's CP/M Machines

Integration into Tomorrow's UNIX Environments is Anticipated

Industry analysts now agree that UNIX will be the dominant operating system for 16-bit microcomputer systems.* UNIX, which is widely recognized as the best operating system ever developed, is written in the powerful systems programming language "C". Because of this, applications programs written in "C" can interact directly with the operating system, giving them a clear-cut advantage over programs written in other languages.

Leverage is a general purpose information management utility now available for use with 56K CP/M machines. Since it is written entirely in "C", Leverage can easily

be integrated into future UNIX systems. This gives current Leverage users the capabihty of upgrading to 16-bit micro systems without costly re-programming or database conversions.

Leverage combines a number of powerful tools, including full screen data entry, report generation, word processing and subset extraction, into an integrated, easy-to-use package. The Leverage system allows you, for example, to computerize your mailing lists, personnel files, or inventory system. (Leverage can outperform, feature for feature, any mailing list program on the marlcet.)

*See, e.g., Byte Magazine "Bytelines" column of Nov 1980, Dec 1980 and Feb 1981; Comm. ACM 24,2 (Feb 1981), 57-58; Sept 1979 Byte p. 82. Leverage is a trademark of Urban Software Corp., UNIX of Bell Labs, CP/M of Digital Researcti.

Leverage Program $185

Manual Alone $ 15 (Credited to subsequent program purchase)

Leverage Newsletter $ 10/year (First year included with purchase)

For complete details on Leverage and current information on hardware compatibility, call or write for a brochure.

Urban Software Corporation

19 West 34th Street • New York, N.Y. 10001 • (212) 947-3811

(212) 986-7690

MAIL ORDER ONLY

Micro Computer ^om Onc Stai> For.. .Quality and Hvga Savioa*

v^uiiipuLer

DISCOUNTc

QVALHY • DELIVERY • SERVICE

60 E. 42nd St. Suite 411 New York, NY 10017

CENTRONICS

CALL FOR PRICES

ATARI

800—$795

APF

IMl - $495

IM2 - $988

COMMODORE

16K - $888 32K - $1088 2022 - $695 2040 - $1088 8050 - $1535 8032 - $1495

XYMEC

HQ 1000 - $2395

NEC

SPINWRITER

5510 - $2795 5520 - $2990

SALE!

EPSON MX-80 EPSON MX-70 MX-80FT

PAPER TIGER 445 & 460 & 560

CALL FOR PRICE

SUPERBRAIN*

32K - $2445 64K - $2749 64KQD - $3395

DIABLO 630 $2195

1730 - $2195

MAIL ORDER ONLY

Send Certified Check (Personal or Company Checks require 2 weeks to clear.) We pay all shipping and insurance charges except items marked with asterisk. VISA, MasterCharge add 5% N.Y.S. Residents add appropriate sales tax.

* (DENOTES ITEMS SHIPPED F.O.B. NYC)

PHONE (212) 986-7690

pages; softcover, ISBN 0-918398-31-2, $12.95.

33 Challenging Computer Games for TRS-80/Apple/ PET, David Chance. Blue Ridge Summit PA: Tab Books Inc, 1981; 13 by 21 cm, 256 pages; softcover, ISBN 0-8306-1275-0, $7.95; hardcover, ISBN 0-8306-9703-9, $14.95.

Troubleshooting SolidState Circuits, G Loveday and A Seidman. Somerset NJ: John Wiley & Sons Inc, 1981; 23.5 by 19 cm, 110 pages; softcover, ISBN 0-471-08371-2, $7.95.

Understanding Computer Systems, Harold W Lawson, Jr. Linkoping, Sv\/eden Harold W Lawson Jr, 1979 20.5 by 29 cm, 150 pages; softcover, ISBN 91-7372-222-9, $15.25.

Understanding Microprocessors, Lloyd Rich. Reston VA: Reston Publishing Company Inc, 1981; 16 by 23.5 cm, 296 pages; hardcover, ISBN 0-8359-8057-X, $17.95.

Without Me You're Nothing, The Essential Guide to Home Computers, Frank Herbert w^ith Max Barnard. New York: Simon and Schuster, 1980; 16.5 by 24 cm, 304 pages; hardcover, ISBN 0-671-41287-6, $14.95.

Word Processing, Rod Van Uchelen. New York: Van Nostrand Reinhold Company, 1981; 20.5 by 23.5 cm, 128 pages; softcover, ISBN 0-442-28646-5, $7.95. ■

This is a list of bool<s received at BYTE Publications during this past month. Although the list is not meant to be exhaustive, its purpose is to acquaint BYTE readers with recently published titles in computer science and related fields. We regret that we cannot review or comment on all the books we receive; in° stead, this list is meant to be a monthly acknowledgment of these books and the publishers who sent them.

402 May 1981 © BYTE PublicaUoiu Inc

Circle 309 on Inquiry card.

Circle 168 on Inquiry card.

MODEL PC-10: Finger Controlled

Desoldering Systems

REMOVE ANY COMPONENT FROM ANY PCB ...QUICKLY AND SAFELY

MODEL PC-20: Footpedal Controlled

STANDARD SYSTEM FEATURES

■ Lightweight and Portable

■ Internal Vacuum Pump

■ Sodr-X-Tractor Handpiece

■ Variable Temperature Control

INCORPORATED

9893 Brewers Court ■ Laurel, Md. 20810 ■ phone (301) 490-9860

Who is it for? Everyone

INTRODUCING

tiLOBAL™ DATABASE MANAGEMENT SYSTEM©

The Only System Your Microcomputer Will Euer. Need

Extremely comprehensive, versatile user-oriented management system for database creation and list maintenance. Runs under CP/M* and CBASIC2** on a microcomputer system in only 48K RAM.

Completely user-defined file structure with sequential, random and linked file maintenance; user-defined number of fields; data transfer between records; high speed search algorithms; built-in ISAM; fas! sort/merge utility; record selectable output can be formatted and printed on uarious forms (labels, envelopes, etc.); links to CP/M commands or programs with automatic return to Global.

Supplied on standard 8" IBM disk (TRS-80 Model U), complete with BASIC subroutine library in source code, with comprehensive

manual.

• Trademark ol " Tradeirmrk ol Shipgng and

Di9"al Hesearch Software Svslems Handling 't'.^llll

included

MANUAL ONLY . . .$30

DEALER INQUIRIES WELCOME

GLOBAL PARAMETERS

1505 Ocean Ave., Brooklyn, N.Y.

11230 212/258-5003

SINGLE BOARD COLOR VIDEO AND SOUND GENERATOR KIT $350'

COLOR VIDEO KIT $320'

•STANDARD KIT ll\ICLUDESTMS9918, ADD $25 FOR TMS 9918A.

COLOR VIDEO PROCESSOR

• Text, Graphics, Animation • 16 Colors • 256x 192 Resolution • NTSC Composite Video Output • Uses TMS 9918

• Includes I/O Mapped 16K Video Memory • 3D Simulation with 32 Video Sprites • 2 Byte X-Y Positioning • Real Time Clock • 8 Level Interrupt Selection • Inexpensive RF Modulator allows easy connection to any color TV • Video over Video and Extended Graphics II Mode with TMS 9gi8A •

PROGRAMMABLE SOUND GENERATOR

• Music. Sound Effects,ToneSignaling, Ultrasonics • 27Hz to 111 KHz Range • 3 Programmable Analog Channels with Separate Frequency, Volume and White Noise Control • 10 Selectable Envelope Wave Shapes under Software Control

• Two 8-Bit Programmable I/O Ports for use as External Keyboard/Display Interface • Power Ampllfierfordriving External Speaker •

Texas residents add 5% sales tax. Prices include complete documentation with programming examples. PC board is solder-masked with gold contacts. Add S100 lor assembled and tested units. Send S14.50 for 120 page manual, refundable with order. Compatible with Z80, 8085 and 8080 at 2 or 4 MKz on S-100 buss.

ELECTRONIC DESIGN ASSOCIATES

P.O. Box 94055 Houston, Texas 77018 (713) 999-2255

Memory Boards for ATARI™ 800 & 400 Computers

Assembled and Tested Ready to plug in

Completely Compatible One Year Warranty

No Modifications necessary

16K $ 99.95

16K with gold plated connector tabs 109.9S

32K with gold plated connector tabs 199.95

Visa and Mastercard accepted Quality discounts available Dealer inquiries invited

Anderson Peripherals, Inc.

P.O. Box 629 Richardson, Texas 75080 214-231-6866 ™ATARI is trademark of Atari Corp.

Circle 146 on Inquiry card.

Circle 26 on Inquiry card.

BYlCMayl981 403

Circle 295 on inquiry card.

FINDING SOLUTIONS AND BEING COMPETITIVE IS OUR BUSINESS.

Having problems and looking for a computer to help solve them? Are you finding computer dealers come in one of two ways? Either Full system support witii Full price or Take it or Leave it with Low price. At Omega we don't believe that you should have to make a choice. Yes, we're in business to sell products but also, to solve your = problems. Our prices will be the ^ lowest possible. Our support and product quality will be second to none. Check out our Mail Order prices in this ad (our retail prices will be higher). See if you don't agree with our first claim. For our second claim, call us with your data processing needs and problems. Better yet, come in and see us. Finding solutions and being competitive is our business. We never forget either of them.

:applG computer

■ Authorized Dealer

APPLE ill SCALL

APPLE II "PLUS" 48K $ 1169.95

HEWLET PACKARD 85 or 83 $ CALL

APPLE II ACCESSORIES:

Disk II with conlroiler $ 535.00

Disl< II 2nd drive 455.00

Graphics Tablet 665.00

Language System with PASCAL 395.00

Silentype Printer W/Int 526.00

Integer Firmware Card 152.00

Microsoft 2-80 Softcard 259.00

Videx videoterm 80 col Card 279.00

Sanyo 12" Green Monitor 269,00

Mail Order Terms of Sales: Price based on prepaid orders. NO COD s. Visa or Master Charge orders add 3°q to purchase price. Allow 14 worl<ing days for personal and company checks to clear Order under S100 00 add S3.00 lor shipping and handling. All orders (unless specified in ad) within Continential U S shipped U P S. no charge APO or out of Continential U.S. write or call for shipping charges. All prices subject to change and all offers subject to withdrawl without notice. CA residents add 6% sales tax

OMEGA Mm nmvmm

The Problem Solving Company 3447 Torrance Boulevard • Torrance, California 90S03 • (213) 370-945S

Supplies:

Scotch Diskettes - Best of Qualityl

price per box of (10)

744-0, 10, 32 $ 27.00

740- 0 SS/SD 0 Sector 31.00

741- 0 SS/DD 0 Sector 37.00

743-0 DS/DD No Format 44.00

New Products:

Videx L/C Adapter 110.00

Microsoft 16K RAM Card 169.00

D,C, Hayes Micromodem II 315.00

Novation DCAT Modem 195.00

EPSON MX-80 CALL

mRRK 6QRDDn

COMPUTERS

DIVISION OF MARK GORDON ASSOCIATES, INC. P.O. Box 77, Charlestown, MA 02129 (617) 491-7505

COiMPUTERS

Atari 800 W16K 799.00

4K Model Ml 599.00

Model II64K System 3499.00

16K Model III 879.00

DISK DRIVES

40 Track S'A inch drive 314,00

BOTrack 5%. 544,00

4 Disk Drive Cable 39,00

PRINTERS

Centronics 730

Epson MX80 Call

Epson MX70 Call

Centronics 737

Okidatafvlicroline83

Okidata Microline 82,,.,

Integral Data 440G

NEC 5Si0w-tractor.... Okidata Microline 80..., Diablo 630

, 599,00 for price for price , B49 00 999,00 7 29,00 999,00 2679,00 , 499,00 249500

IMISC HARDV/ARE

Expansion int TRS-80IOk), , , 269 00

Novation D-Cal Modem 166,00

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This group is dedicated to using micrcomputers in the field of planning. The emphasis is on the use of microcomputers for physical or social planning, in public agencies, academia, or private firms. The dues are $10 per year, which includes a bimonthly newsletter.

For further details, contact the group at 1204 People's Bldg, 60 Monroe at Ionia, Grand Rapids MI 49503, (616) 454-9375.

MP/M Users Group

MAPS is an MP/M users group that publishes a quarterly newsletter called MAPS Digest. The newsletter contains application reports, compatibility issues, MP/M support product reviews, and problem areas and solutions discovered by MP/M users. Members receive a list of programs in the MAPS software library and can participate in the MAPS bulletin-board service. Contact Digiac Corporation, Commercial Products Division, 175 Engineers Rd, Smithtown NY 11787, (516) 273-8600.

Monadnock Computer Society

The Monadnock Computer Society meets on the first Thursday of each month at the Keene State CoUege Library in Keene, New Hampshire. Club members own and use the most popular microcomputers on the market. The club is actively seeking information from other organizations. MCS Output, a monthly

404 May 1911 © BYTE Publicatians Inc

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Domestic; $2.75 Canada and Mexico; $3.75 Foreign. September 1977 through October 1979 issues are $2.50 Domestic; $3.50 Canada and Mexico; $4.50 Foreign. November 1979 to current is $3.00 Domestic; $4.00 Canada and Mexico; $5.00 Foreign. Send requests with payment to:

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Computer Neophyte Newsletter

ComputerTalk Associates, publisher of ComputerTalk for the Pharmacist, has introduced a monthly newsletter for first-time buyers and users of small-business computers. The newsletter covers software, hardware, legal issues, new products, and it gives advice on what to look for when piirchasing a computer. It is designed for readers with no prior background in electronic data processing. Subscriptions are available for $35 per year from ComputerTalk Associates, Whitpain Office Campus, 1750 Walton Rd, Blue Bell PA 19422, (215) 825-4918.

TRS-80 Users Group of Delaware

If you live in the Delaware Valley area, there's a users group that would like to hear from you. For more information on the group and its activities, contact Tim J Dide, 1116 Piper Rd, Wilmington DE 19803, (302) 478-7415.

PDP-8 Users Software Exchange

There's a free software exchange service for DEC (Digital Equipment Corporation) PDP-8 users. The service allows users to submit their software for exchange credits that can be used to obtain any software listed in the Quarterly Software Exchange Bulletin. Also available is the electronic magazine Digital Digest. Contact PDP-8 Software Exchange, 3169 Holcomb Bridge Rd, Suite 307,

406 May 1981 ® BYTE Publications Inc

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M^hat do/ou want your computer and video pla/ertodo thatthe/can'tdonow?

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Clubs and Newsletters _

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Computernews for Dentists

This monthly 4-page newsletter contains information about computers, developments in technology, and explcinations of components. The newsletter shows dentists how the computer can help in their work, especially in management. Computernews for Dentists is published by Praxis Computer Inc, 431 St Paul St, St Catherines, Ontario, L2R 3N4, Canada, (416) 688-2611.

MICRO

MICRO (Midwest Interactive Computer Organization) meets on the second

Saturday of each month. Dues are $15 per year. Members own Apple, TRS-80, OSI, TI 99/4, KIM, Technico, and other makes of computers. Contact MICRO at 1520 W Capitol Dr, Appleton WI 54911.

The Aurora

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The Aurora Computer Society meets on the second Wednesday of each month at the Holyrood School, 7920 94th Ave, Edmonton, Alberta, at 7:30 PM. The group is involved in computer-to-amateur radio interfacing and BASIC classes. Members own PET, TRS-80, SwTPC, and other kinds of microcomputers. A monthly magazine. Intercom 80, features technical articles and news of the Society. They are interested in communicating with other groups. Contact Bob Huntingford, POB 4342 South Edmonton, Alberta; or Bill Gillespie, 10129 90th St, Edmonton, Alberta, T5H 1R5, Canada.■

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May 1981 © BYTE Publications Inc 407

A File Catalog System for UCSD Pascal

Edward Heyman 300 Center Hill Rd Centerville DE 19807

It doesn't take long to accumulate a large number of disks with assorted software, particularly if you insist on a reasonable amount of backup. Finding a program you worked on two months ago can be a problem without some type of file organization. Ward Christenson provided the CP/M world with that organization in his UCAT disk catalog system. I'd be lost without it.

As my collection of UCSD Pascal files grew I needed a system similar to UCAT to cope with the problem. Hence, I created CATALOG (see listing 1). Written in Pascal, it does all the things that UCAT does as fast or faster than UCAT (even though UCAT is written in assembly language). A new directory can be merged into a 600-entry catalog in about 30 seconds. A search for a file in a 600-entry catalog takes less than a second. A 600entry catalog uses about thirty-six blocks, as does the backup file. The program code file and pointer file use another twenty blocks for a total pf ninety-two blocks.

What CATALOG Does

CATALOG maintains a file of records in which each record is similar to a UCSD Pascal directory entry. The record contains the name of the volume, the file name, the type of file, the date the file was last changed, and the length of the file. CATALOG gets the records directly from a volume directory during UPDATE, Once the CATALOG file is filled with records you can locate a fUe with the SEARCH command.

Being lazy, I like to have my machine do as much of my work as possible, so I've added a few bells and whistles to the essential features.

Using CATALOG

For the CATALOG program to work, the files MASTCAT.DATA and CAT.POINT.DATA must be on Drive five. If they are not, the program asks if you want to create them. The first time the program is run you must respond with a "Y" to the prompts for file creation before you can proceed.

Thereafter, executing CATALOG will bring forth the command line:

CATALOG-S)earch D)isplay B)ackup U)pdate R)emove Q)uit.

The S Command

Entering "S" will put the program in the Search mode with the prompt:

ENTER THE NAME OF FILE TO BE FOUND

Uppercase must be used for the file name. Wild-card searches can be made by replacing the wild-card section with " = ". For example, the following entries may be made to find CATALOG.TEXT:

CATALOG.TEXT

CAT=

=LOG.TEXT

The directory of an entire volume can be obtained by typing the name of the volume followed by ":".

Entering file name FREE. SPACE will display a list of all the cataloged volumes, the available space, and the most recent date of catalog update of each volume.

The output of the Search command can be directed to the printer by typing "< " before the name of the file to be searched.

The D Command

Entering "D" in response to the main prompt line will display the entire catalog in alphabetical order.

The B Command

Entering "B" in response to the main prompt line will display all files that exist on only one volume (all files that do not have a backup). The routine checks only for the same file name; therefore, files with the same name but different dates are considered to be backed up.

The U Command A response of "U" to the main prompt line will activate

408 May 1981 © BYTE PublicaUons Inc

the update routine, which will produce the prompt:

ENTER UNIT NUMBER CONTAINING UPDATE VOLUME

If UNIT 5 is selected, the catalog file will be updated with the contents of the volume containing the catalog files (with the exception of MASTCAT.DATA). For all other volumes UNIT 4 should be used.

The update procedure will first rename the main catalog file (MASTCAT.DATA) to BACKCAT.DATA and then read the directory for the volume on the selected unit and create a file name FREE.SPACE with the unused space on the volume. It will then sort the files by alphabetical order and merge the volume list with the catalog file (MASTCAT.DATA) and at the same time create the pointer file (CAT.POINT.DATA.).

While merging, any file names added will be displayed on the console terminal and any files that were previously on the volume but were removed will be removed from the master file and displayed as having been deleted. After completion, the number of entries in both the main and backup files will be displayed.

The beauty of Pascal is its selfdocumenting features—the program should not be difficult to

follow.

The R Command

Entering an "R" in response to the main prompt will invoke the prompt line:

ENTER NAME OF VOLUME TO BE REMOVED-

Entering a volume name and a carriage return will cause all entries in the main catalog file for the selected volume to be removed from the file and to be hsted on the terminal.

The Q Command

To leave CATALOG enter "Q". UNIT 4 will be checked to see if it contains the booted system volume; if not, a prompt to insert the original system volume will be displayed on the terminal before the program is exited (to prevent a system crash).

How the Program Works

The beauty of Pascal is its self-documenting features—the program should not be difficult to follow.

Since most systems will not have sufficient memory to hold a copy of both the old (BACKCAT.DATA) and the new catalog (MASTCAT.DATA) at one time, the files are read in and written out in sections. OCAT and NCAT are arrays that hold the records read from the old file and the records to be written to the new file, respectively. The size of these arrays is determined by the constant MAXREC. MAXREC should be adjusted to suit your memory size. NREC and OREC are variables associated with the number of records read or records written during the current read or write. DREC is associated with the

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Circle 423 on inquii^ card.

May 1981 © BYTE Publications Inc 409

number of records in the directory. OTOTREC and NTOTREC are the total records read or written to or from a file.

In order to speed the action of the SEARCH command a pointer file is created during UPDATE. The index to the pointers are the characters "A" to "Z". The array holding the pointers is called DEXRAY and is stored on disk in the file CAT.POINT.DATA. The pointer list is created by calls to the procedure SETDEX. It is written to file by procedure WRITEDEX and read into array DEXRAY by procedure READDEX.

Procedure BACKUP checks to see if the file name of a record is unequal to its predecessor and successor. If it is, it is not backed up. Since the array is not large enough to hold all of the catalog file, provisions must be made to compare the last entry in one array with the first entry in the next array. The Boolean variables PASS and UNBACK are used for this purpose.

To simplify the logic of procedure MERGE, several IF statements as well as the CASE statement have been used. The problem may be stated as follows:

•If the current directory record file name is less than the current old catalog record file name, insert the directory

record in the new catalog and increment the new file pointer (NREC) and the directory pointer (D). •If the current directory record file name is equal to the current old catalog record file name, check the volume names. If the current directory record volume name is less than the old catalog record volume name, insert the directory record and increment the new catalog (NREC) and the directory (D) pointers. If the current directory record volume name is equal to the old catalog record volume file name, insert the directory record and increment NREC, OREC, and D. If the directory record volume name is greater than the old file record name, insert the old catalog record into the new catalog and increment the new catalog and old catalog pointers. • If the current directory record file name is greater than the old catalog record file name, insert the old catalog record in the new catalog and increment the new catalog pointer and the old catalog pointer. If the directory record volume name is equal to the old file record volume name, do not enter the record in the new catalog, and simply increment the old catalog pointer.

I hope that you will find CATALOG useful in keeping track of your files and programs. ■

Listing 1: A disk catalog system for UCSD Pascal. This program maintains a file of records in which each record is similar to a UC5D Pascal directory. Each record contains the name of the volume, the file name, the type affile, the date the file was last changed, and

the length of the file.

•{:$5:h;>-<:l console;ml printer5>-{:l cat.prn.text> program catal0q5

•t* written ba edwsrd heyman *>

■{:* 300 center hill road *> ■{:* centerville delawsre 19807 *>

CONST

BLANKS = ' ' f

MAXREC=^200y MAXREC. 1=201 f

NFILENAME='*5;MASTCAT,DATA'J 0F"ILENAME='*5:BACKCAT.DATA' f PF3:LENAME='*5:CAT»POINT»riATA't CLEARSGREEN=12J

TYPE

DATE^RECORD = PACKED RECORD

MONTH! 0..12f DAY J 0..31? YEAR? ©♦.lOO

ENDf

DIR...SIZE = 0 w77f

yOL ID = STRINGC7Df

FILE-ID = STRINGClSn?

FILE-TYPE = (UNTYPEDi-XDISKrCODErTEXTr

INFO I.TIATA , GRAF r FOTO r SECUREDIR ) i DIR-RECORD = RECORD

FIRST-BLOCK: INTEGERf

LAST-BLOCK; integer? Listing 1 continued on page 411

410 May 1981 © BYTE Publications Inc

Listing 1 continued:

CASE DIR-FILE-KINDJFILE-TYPE OF SECUREDIR»UNTYPED}

(DIR_V0L„NAME:VOL-IDf ZERO_BLOCK» NUM_.OF...F]:LESf TOTAL..-BLOCKS: INTEGER} l,..AST...BOOT:nATE_RECORD) *

XDISKfCODEfTEXTrINFO>DATA»

GRAFfFOTO*.

(DIR.... F :i: I... i;;:.... n a m e : f i l e_ i D f

LASTBYTE: :l » »512r riIR_FILE_DATE: DATE-RECORD >

END?

CATALOG_RECORD=PACKED RECORD

yOL._NAME; VOL...IDJ FILE-NAME :F:rLE_.iD; FILE-KIND:FILE-TYPEf FILE-DATE J DATE-RECORD i FILE-SIZEtO..988*

END?

DIRECTORY = arrayi::dir_size: of dir_record»

CATARRAY = ARRAY COt.MAXRECn OF CATALOG-RECORD J FILEN STRINGC20:f RECNUM = 0.«MAXREC-i; INDEX = 'A'.•'Z'>

INDEXARRAY = ARRAY CINDEX 3 OF INTEGER J

NREC fNLREC fOREC r OLREC,DREC»DLREC{RECNUM t

NTOTREC»OTOTREC:0».2047J

REMOU T NFILEEND fOFILEENDf DONE J BOOLEAN i

CH:CHARf

DEX: INDEX?

DEXRAY J INDEXARRAYJ

P * FILE OF CHAR? -Cused to switch from console to printer>

K)0\... y TEST , SYSTEMUOLUME t UOL_ ID r

CATFILEjOCATFILEtNCATFILEJFILE OF CATALDG-RECORDt

NCAT T OCAT : CATARRAY f '-•'^'"^ '

HARDWORKING SOFTWARE

DISSAX/ A cunning two-pass 8080/Z80 disassembler that produces print and directly assembleable source outputs. DISSAX IS a sophisticated cross referencing tool that puts references where they belong, as line comments, not in a separate output section. Requires 16K CP/M. Manual $5/ Object $85/ Source $150.

DISSAX/TXTBOOK/FRMFLEX

CP/M is a trademark of Digital Research. CBASIC2 is a trademark of Compiler Systems, Inc. Manual prices applicable to software purchase.

TXTBOOK/ Text formatting software for sophisticated document Delivered by CEXEC "^^r^

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FRMFLEX/ A complete forms handling system allowing independent CRT input and printer output formats. The only system of itsl<ind, frmflex gives you complete control over forms creation, updating, and data entry with simple user oriented techniques. Requires 32K CP/M and addressable cursor CRT CBASIC2 INT and Microsoft BASIC COM formats. Manual $20/ Object $175/ Source $350.

Source $600.

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San Francisco

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Circle 66 on inquiry card.

May 1981 © BYTE Publications Inc 411

Listing 1 continued:

FUNCTION LOOKUP(FN:FILEN):BOOLEANfFORWARD*

SEGMENT PROCEDURE INITIALIZED yAR

IJRECNUMJ CAT:CATARRAYf

diexfilejfile of indexarray?

beg:i;n

if (not lookup(nfilename)) then begin

writelnc'there is no file named 'rnfilenamer' on this disk')f writelncdg you want to create a ' f nfilenamef ' ■cy/n>')j

REPEAT READ(CH)

UNTIL <CH IN C'Y'f'«'»'N','ri'3)>

IF (<CH<>'Y') AND (CHO'y')) THEN EXIT<CATALOG) J writelri('FILLING ARRAYCO]')? WITH CATC03 DO BEGIN

vol_.name:=' '»

FILE...NAME5 = ' ' f

F:i:LE....KIND:=UNTYPEDf FILE...DATE. MONTH :=0f FILE-DATE*DAY:=0J FILE-DATE.YEAR J=0> FILE-SIZE J=0» END?

FOR ir=l TO MAXREC DO CATCI3t=CATC03J writ.elPi<'ARRAY IS FILLED')? REWRITE < CATFILE»NFILENAME)? FOR IJ=0 TO MAXREC DO BEGIN

CATFILE'":=CATCI3? PUT(CATFILE)? ENDy {if or I> CLOSE(CATFILEfLOCK) END-{:.i.f>

ELSE WRITELNCTHE FILE ' »NFILENAMEf' ALREADY EXITS ON THIS VOLUME ')?

Listing 1 continued on page 413

.00

Integral Data Systems Model 445 Printer... Televldeo Model 950 , , 1295.00 Industrial Micro Systems 349.00

MORE SPECIALS

Livermore Accoustic

Coupler {195.00

Centronics Micro Printer 349.00

5" Scotch Oist<ette Box 34.95 Scotch Diskette

Box.

39 95

We have a full staff of Programmers and Compoter Consultants to design, configure and deliver a Turnkey Computer System tc meet your specific requirements

We cariy a full line of; ADDS QUME CROMEMCO, SCOTCH, MAXELL VERBATIM, ALPHA-MICRO, ATARI, INTEGRAL DATA, LIVERMORE COUPLERS HA2ELTINE, TEXAS INSTRUMENTS DIGITAL MICRO SYSTEMS and others

SYNCHRO-SOUND enterprises, inc.

THE COMPUTER PEOPLE 125 Mineola Ave., Roslyn Hts., N.Y. 11577 Phone Orders call; 516/484/1852 • Toll Free; 800/221-2320 • TWX 710-582-5886 systems center

10-4 Daily & Saturday

412 tvlay 1981 © BYTE PublicaUona Inc

Listing 1 continued:

IF NOT I...O(DKIJP(PFILENAME) THEN BEGIN

WF<:i:TELN('THERE IS NO FILE NAMED ' »PFILENAME r ' ON THIS DISK')» WRITELNCDO YOU WANT TO CREATE A ' >PFILENAMEf ' •CY/N>')f REPEAT

F^EAIKCH)

UNTIL (CH IN C'Y'f'a'f'N'»'ri':])J

IF <<CH'<>'Y') AND (CHO'a')) THEN EXIT (CATALOG) J FOR DEX:='A' TO 'Z' DO DEXRAYCDEX3:=0» REWRITE(DEXFILEtPFILENAME)f DEXFILE":=DEXRAY# PUT(DEXFILE); CLOSE(DEXFILEfLOCK>» ■ WRITELN<PFILENAMEf' WRITTEN TO DISK') END-Cif>

ELSE WRITELNCFILE ' f PFILENAMEf ' EXISTS')? ENDKirdt>

FUNCTION LOOKUP?

•Creturns TRUE if filename present FALSE if not>

VAR

I0R}0».15?

BEGIN

•<:*i-.>

RESET(CATFILE»FN)f

IORJ=IORESULT»

CLOSECCATFILE)?

<.$i\y

IF <IOR=0)

THEN LOOKUP JsTRUE ELSE BEGIN

LOOKUP J=FALSE*

IFdOROlO) THEN WRITELN<' lORESULT FOft ENDf-Celse> ENDKlookup>

»FN»' IS 'rIOR)J

Listing 1 continued on page 414

^ THE ULTIMATE INVENTORY CONTROL SYSTEM

n for the TRS-80!

Why the ultimate? Because it turns your Model II TRS-80 microcomputer into a powerful control system that keeps track of your inventory by both kind and class, so you can tell not only how many jelly beans you've got, but how many of

them are red and how many are black. And how many red jelly beans are big. And how many are small. And how much they cost. Better yet, if you consume your inventory by kit, just tell the system what's in the kit. Then when you withdraw some kits, it automatically adjusts the inventory level for all the components in that kit. When the inventory gets down to a predetermined level, it even tells you it's time to order and where to order. And with the wide variety of reports it can supply, you keep track of costs, usage patterns, and a host of other variables. But best of all, the system operates just like the manual inventory control system you're used to. so you don't have to learn a new way of doing things — its easy-tofollow self-teaching manual makes it a snap to run.

The system requires a Model II TR.S-80 with 64K memory, a Qtf^'f'i'Ci'SlV

132-column printer, and one or two 8" floppy disk drives. vJV* !.€»■. £ *

Single diskette system with up to 950-item capacity $385 35 Deville Drive, Selden, NY 11784

Two diskette .system with up to 2450-item capacity $445

Manual only (credited towards purchase price) .....$ 50 516-561-1891

S.vsicm comes a;id> 10 use. source code liccn.se is available, dealer inquiries invited. ™TRS-80 is a registered trademark Tandy Corporation Circle 374 on inquiry card. May wsi © BYVE PublicaUons inc 413

Listing 1 continued:

PROCEDURE WAIT* BEGIN

(•30TOXY(10f24) »

WR.I.IE('PRESS SPACE BAR TO CONTINUE')» READ(CH) EN»Kw3it>

PROCEDURE MEM<PN:STRING)*

BEGIN

writelri('MEMORY AVAILABLE AT PROCEDURE 'rPN*' = 'rMEMAVAID;

end;

PROCEDURE GET_SYS_V0L(VAR yOL;VOL_ID)» •Caets name of volume in drive 4> MAR

integer; sps:stringi:i.A3» avol:vol_idj niRt directory;

BEGIN

UN;i:TREAD(4f DIRi:03»2048»2) » volj=DIRC03»DIR_OOL_NAME;

SPS:-COPY(BLANKS,1,7-LENGTH < VOL))i AVOL{=CONCAT( VOL»SP£)); ENDKs5et_sy5-.vol>

PROCEDURE READDEX;

breads the file of pointers to the first occurrence of each letter in the alph*

VAR

DEXFILE t FILE OF INDEXARRAYJ

BEGIN

reset(dexfile fpfilename)) dexray:=dexfile'"; get(dexfile)» close(dexfile);

ENDKre3dde>£>

PROCEDURE ENTER-VOL^NAME i VAR

SPS ♦ vol id; Listing 1 continued on page 415

Softbus'

Tiim your ^ple* inside out

brings the Apple's bus to your workbencti to be convenugged into your breadboards. Don't let a drop of solder or lestroy your computer. Witti ttiecoversecured and Softbus, your Apple Is safe, prolBCtedandaccesslblefor easy clrcultinterng, Softbus Is the Ideal, low cost design and interface tool tiobbyists, technicians and engineers. Write or give us a coii for details. ^ ^

rAA^\-,,-,r,^Aj, ^ >^ Suggested retail S80.00.

(415)747-0614 / \ Dealer inquiries invited.

Moil orders accepted.

'Apple is

"Softbus

a registered trademark of Apple Computer Inc

s o trademark of Posspof t Designs, inc

PASSPORT DESIGNS

r\/)arketing

Br.. ?'041

Minneapolis, fvirj 56421

Headquorters

la Hondo CA94020

414 May 1981 © BYTE Publications Inc

Circle 317 on inquiry card.

Listing 1 continued:

BEGIN

VOL.: = ' '9

r.epe:at

wr:[te(chr(clearscreen) ) ?

WR:i:TE('ENTER NAME OF VOLUME TO BE REMOyED —> * READLN(VOL)J UNTIL <LENGTH(VOL)<=8)»

IF (PDS( ' t ' fVODOO) THEN DELETE ( VOL r POS ('t ' f VOL ) r 1) > SPS:=COPY(BLANKSf1r7-LENGTH(VOL))5 VOL J=::CONCAT(VOLfSPS) f WRl TELNCVOLf ", ') i DREC:=0 END»-Cen te r_vol _n3ffie>

PROCEDURE PRINT-DATE (REC:DATE_RECORD)» •Cprints date to console or printer.! BEGIN WITH REC DO BEGIN

write(p»day:3t'-')i

CASE MONTH OF

It lJRITE(Pf ' Jan') f

2: WRITE(P»'Feb'>J

3J WRITE<P»'Msr')r

4{ WRITE(Pr'Apr');

5J WRITE(Pt'May')>

61 URITE(Pf'Jun')f

7t WRITE(Pf'Jul')f

8{ WRITE<P»'Ausf') ?

9? WRITE(Pf'Sep')?

lO: WRITECPt'Oct')5

11: WRITE<P»'Nov')?

12: WRITE(P»'Dec')? ENDKcase}

WRITE<Pf»YEARt2»' 't3)t END»-Cwith>

END»-Cprint_d3te3" Listing l continued on page 416

COMPUTER EQUIPMENT & SOFTWARE

EVERY MONTH

BUY, SELL OR TRADE ALL TYPES OF COMPUTER EQUIPMENT AND SOFTWARE (pre-owned and new) among 20,000 readers nationwide in BIG (11x14") pages. Classified ads are only 10' per word and are indexed for easy and fast location. Subscription: $10 a year / 12 issues. Money back guarantee. Sample copy, $1.50.

campuTSR shiapi^sR

P.O. Box F.14 Titusville, FL 32780 (305) 269-3211 MasterCard or VISA subscription orders only, call TOLL FREE 1-a00-528-6050 Ex.' 1B4.

HEADERS

34 PIN HEADER 3M 3413-1003 SI.25 EA 40 PIN HEADER ALPHA SI.50EA 50 PINHEADER 3M 3433-1002 $1.75 EA 40 PIN CONNECTOR 3M 3417 $1.50 EACH

22/44 EDGE CONNECTOR

TIN SOLOERTAti. .156"x .200"

LAHGE QUANTITIES AVAILABLE 11 35 each lOlof SI2 50

7-17vdc S.S. BUZZER

Sourid output 70(18 0) 20 cm

Si 25 each

FLAT LEVER HANDLE 'MINI TOGGLE

SPOT HATED

6 AMPS ftii l?5 V 1,4 - 40 BUSHING

SI.00 each

10 for Sa 50

Litronix FRL-4403

>J FLASHER LED

' dlf lusMl rad lad

wllhbuill )nllath(ngunil

T 1 package

pulse rale 3fii 5v 20 ma

2 tO(Sl.70

ALL CLCCTROfllCS CORP.

905 S. Vermont Ave. Los Angeles, Calif. 90006 • ouaninies Limited (213) 380-8000 ; O'"*"

Mon. - Fri. Saturday ' sh?ppir.°g°usA 9 AlVI ■ 5 PM 10 AfW • 3 PM • ca«( Res^Adde-/.

• Prompt Shipping

SEND FOR FREE CATALOG

MEMOREX

Floppy Discs

Lowest prices. WE WILL NOT BE UNDERSOLD!! Buy any

quantity 1-1000. Visa, Mastercharge accepted Call free (800)235-4137 for prices and infonnation. All orders sent postage paid.

PACIFIC EXCHANGES

100 Foothill Blvd. San Luis Obispo, CA 93401. (InCal call (805) 543-1037.)

I

Circle 87 on inquiry card.

Circle 10 on inquiry card.

Circle 311 on inquiry card.

Listing 1 continued:

PROCEDURE PRINT_KIND(FILE_KIND:FILE_TYPE)r •CFrints file type to console or printer>

BEGIN

CASE FILE-KIND OF

XDISKJ WRITE(Pf'B3d block'>»

code: URITE(F>'Code file')? text: WRITE(Pf'Text file')? :i;NFO: WR.TTE(Pr ' info file')? data: URITE(P>'Data file')? GRAF: WRITE(P»'Graf file')? FOTG: WRITE(P»'Foto file')? END? < case > END?-Ci='ririt„kinct>

PROCEDURE PRINT_REC0RD<CAT1{CATALOG-RECORD)? <pririts record to console or printer>

BEGIN

WITH CATl DO , BEGIN

WRTTE(PfFILE_NAME»' ':18-LENGTH(FILE_NAME))? WRITE(PrUOL_NAME.' ':8-LENGTH<MOL_NAME))?

WRITE(PtFILE._SIZE:'4) ? PRINT_DATE(FILE_DATE)? P RIN T KIN D < FIL E _ KIN D) ?

WRITELN(P)?

EMD?<:wi th> END ? -tprint-record;}

PROCEDURE READ_.NEW_.CAT ?

■treads NREC records or to eof from NCATFILE> MAR

i:recnum?

BEGIN

I t:::=:i. jnrec:=Ot

GETCNCATFILE)?

WHILE (NOT EOF(NCATFILE)) DO BEGIN

NCATi:r3t=NCATFILE"? IF ( <NCATi:i3.V0L_NAME=' ')) THEN BEGIN

NREC:=I-lr

NTOTREC:=NTOTREC+NREC? NFILEENDt=TRUE? EXIT(READ_NEW_CAT)?

END y ■{ if !}• Listing 1 continued on page 417

AMS

ADVANCED MICRO SYSTEMS • 26188 ADAMOR ROAD • GALABASAS, CA. 91302 OPEN MON.-FRI. 10-8 SAT. 10-6 Tel.: (213) 880-4670

COMPLETE QUALITY SYSTEMS AT LOW, LOW PRICES !

ALL SYSTEMS ALLOW MULTI-USER, MULTI-TASTING, UPWARD EXPANDABILITY AND INCLUDE:

1. TELEVIDEO 912C

2. ANADEX DP-9500 SERIES

GRAPHIX PLUS PRINTER

3. 64K DYNAMIC RAM 5. PLUS ONE OF THE FOLLOWING DISK DRIVE SETS

a. 2x5 1/4" FLOPPY b. 2x8" FLOPPY c. 2x8" FLOPPY^

(400K BYTES) dM BYTES) (2M BYTES)'

4. DECISION I BASIC UNIT

a. Z-80A CPU 4-TO-6 MHZ.

b. 3 SERIAL & 2 PARALLEL PORTS, e. SUPERVISOR CONTROL IN H8.S.

d. REAL TIME CLOCK.

e. MEMORY MAP.

INCLUDING ONE YEAR FREE WARRANTY ON PARTS & LABOR

FOB

$5500.

FOB

FOR

$5800.

$6300.

. 8" FLOPPY 5 1 /4" WINCHESTER (6MB) FOR

$7900.

Featuring

f. PROGRAMMABLE INTERRUPT CONTROUER.

g. DIGITAL RESEARCH CP/M 2.2 O.S.

h. MICROSOFT EXTENDED DISK BASIC. I.'dISK CONTROLLER

i. DOCUMENTATION.

e. 8" FLOPPY B" HARD DISK (11 MB)fOfl

$8110.

f. 8" FLOPPY 14" HARD DISK (27 MBjfOn

$9195.

SYSTEMS ARE DELIVERED AS AVAILABLE. PRICES, TERMS, SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE. ALLOW 30-60 DAYS

FOR DELIVERY. PRICE FOB CAUBASAS, CA 91302. DECISION I - TRADEMARK OF MORROW DESIGN. PRICES ARE FOR PREPAID (DEPOSIT) ORDERS.

416 May 1981 © BYTE Publications Inc

Circle 8 on Inquiry card.

Listing 1 continued:

IF (I=NLREC) THEN BEGIN

NF^Ec;=:i: j

NTOTREC:=NTOTREC+If EXIT(READ_NEW_CAT)> ENDKif>

l*,=l + l>

GEKNCATFILE)? ENDr-Cwhi:!.©:}

NREc:=i-i;

NTOTREC{=MTOTREC+NREC i NF:i;i...EEND:=TRUEf END»<nre3de3t>

PROCEDURE READ..OLD_CATf

•Oeads OREG records or to eof from OCATFILE> VAR

i:RECNUMr

BEGIN

= J0RECt=0f 6ET(0CATFILE) f

WHILE (NOT EOF<OCATFiLE>> DO BEGIN

0CATCI3}=0CATFILE"* IF <(0CATCI].V0L_NAME=' ')) THEN BEGIN

0REC:=I-1i

OTOTREC:=0T0TREC+0REC f

OFILEENDt=TRUE?

EXIT(READ_OLD_CAT)t

END?<if> IF (I=OLREC) THEN BEGIN

ORECJ=IJ

OTOTREC :==OTOTREC+1 r EXIT(READ_OLD_CAT)f ENDKif>

I♦=1+1f

GET<OCATFILE)J

ENDr-CwhiIe> 0REC:=I-1f

OTOTREC:=0T0TREC+0RECI

OFII...EEND:=TRUEf ENDKre3dc3b>

Listing I continued on page 418

Data

Acquisition and Control for the Ti2S-80*

Eight protected analog inputs

0-5 Vdc 8± 1 bits Eight protected digital inputs Eight optoisolated digital outputs Two joysticl< ports

Up to 4000 bytes/second A/D. Interrupt-driven software. Detailed applications manual for:

• HOME SECURITY —

burglary, fire

• ENERGY MONITOR —

fuel use, etc.

• WEATHER STATION —

temperature, solar

• APPLIANCE CONTROL —

lights, alarms

• GRAPHICS & GAMES —

software Included

The STARBUCK-8882 is fully compatible with any Model I Level II TRS-80. Installation takes less than a minute. Suitable for home and laboratory, the STARBUCK-8882 can also be used with the optional joysticks for graphics & games. With the TRS-80 expansion interface, the STARBUCK-8882 can also be operated off the interrupt clock, acquiring and storing data without interfering in any way with normal TRS-80 operation. The software package allows you to take data while simultaneously using the TRS-80 for any other purpose!

STARBUCK-8882: Includes case, power supply, connector cable, extra expansion card edge, complete software package, and detailed applications manual.

Assembled

and Tested $180.00 ppd.

Manuals &documentation

only $ 4.00 ppd.

To order, write:

STARBUCK DATA CO.

P.O. Box 24, Newton, MA 02162

Massachusetts residents add 5% sales tax. •TRS-80 Is a trademark of Tandy Corp.

May 1981 © BYTE Publications Inc 417

Listing 1 continued:

P'ROCEDURE WRITECAT*

■fwrites NREC records to NCATFILE>

•JAR

:i: JRECNUM?

BEGIN

IF (NTOTREC=0) THEN WITH NCATCOD do

BE(3IN

V(:)L....NAME{ = ' '»

F:i:LE....NAMt;:: = ' '»

FILE_KIND{=UNTYPEDr FILE„.nATE.MONTHt=Of

FILE-DATE.day: =0 5 FILE...DATE. YEAR:=0 5 F:i:i.,.E...STZEt=Of NCATFILE":=NCATCOaf PUT(NCATFILE)i END?

FOR IJ=1 TO NREC DO BEGIN

NCATFIL.E":=NCATCI3J PUT(NCATFILE)f WRITEC,')? ENDP WRITELNJ

NTGTREC t=NTOTREC+NREC?

NREC;j::=^Ov

IF DONE THEN CLOSE(NCATFILEfLOCK)J

ENDr-Cwritec3t>

F'ROCEDURE display;

•{.writes the entire MASTCAT.DAT file to the console> VAR

i:RECNUh>

BEGIN

REWRiTE(pf'console:')i

IF < LOOKUP(NFILENAME)) THEN BEGIN

NREC:-=Of

RESET(NCATFILE»NFILENAME)i

REPEAT

READ_NEW_.CATf

FOR i:=1. TO NREC DO PRINT_REC0RD(NCATCI3) f UNTIL NFILEEND?

Listing 1 continued on page 419

Compatible Z-80 Software

Northstar, SD Systems. Also available on 5" double density Superbrain.®

Bo WeP"St!!ieWa Pt? Si AsSOCiatieS software and hardware design $GOLD DISK$ CP/M®

Available for all 8-5" SS-SD IBM format systems Including TRS-SO"

Un-can your canned software!

7C z-80 Disassembler Feel couped up with your ^ I f- ^ , canned software? Our Z-80 Disassembler

ppd recreates assembly language source files from absolute code enabling users to easily tailor programs to meet their specific needs. The Preconditioner works with the Disassembler to decode ASCII.

$50.

ppd

Great looking letters & reports

Credit cards: Immediate service, free 24 hr. phone - we will credit invoice. Checl<s. M.O.'s: Ten worltday hold. CA. res: Add tax.

aMaiterCard]

E-Z Text A unique word processor organized around user-created text files, embellished with simple control commands, which supports such 'BIG GUYS' features as Automatic Footnoting, Table Spacing, Heading, Paging, Lett & Right Margins, Proportional Spacing and MORE, at a 'LITTLE GUYS' price tag.

State system & controller. Allow time for surface mail. Trademarks: Digital Research. Radio Sfiack. Intertec.

POST OFFICE BOX 1389 HAWTHORNE, CALIFORNIA 90250 213 / 676-5055

418 May 1981 © BYTE PubUcations Inc

Circle 49 on Inquiry card.

Listing I continued:

CLOSE(NCATFILE)?

WAIT? ENi:i{:therr>

ELSE WRITELN(NFILENAMEf' NOT PRESENT')? WR1TELN<'MASTCAT CONTAINS '»NTOTREC»' RECORDS')f

CLOSE(P)J WAitTf END»<displ3« >

PROCEDURE BACKUP*

■(.compares file names and reports files without bsckupJ VAR

PASS rUNBACK iBOOLEAN i NJRECNUM*

BEGIN

PASS: =:FALSE; UNBACK t =FALSEJ REWRITE(P»'CONSOLE}')r IF < LOOKUP(NFILENAME)) THEN BEGIN

WRITE(CHR(CLEARSCREEN) ) f

WRITELNCTHE FOLLOWING FILES ARE NOT BACKED UP')*

RESET(NCATFILE»NFILENAHE)*

REPEAT

3:F (PASS AND UNBACK)

THEN IF (NCATC0D,FILE_NAHE<>NCATC13.FILE-NAME) THEN PRINT_REC0RD<NCATi:03) *

READ_NEW_CATr

FOR n:=i to nrec-1 do

IF ( <ncati::n:;i .file_.name o ncatcn-13 .file_name) and

<NCATCN3«FILE_NAME <> NCATCN+ID,FILE-NAME)) THEN PRINT...REC0RD(NCATnN3) *

PASS:=TRUEr

IF (NCATLNRECJ.FILE-NAME <> NCATCNREC-13.FILE-NAME)

THEN UNBACKJ=TRUE* NCATCOD{=NCATCNRECa»

IF (NFILEEND AND UNBACK) THEN PRINT_REC0RD<NCATCNREC3)?

UNTIL NFILEENDr CLOSE(NCATFILE)f ENDCif}

ELSE WRITELN<NFILENAMEf' NOT PRESENT')* CLOSE(P)* WAIT? ENDv thackup>

Listing 1 continued on page 420

UCSD p-System* for the INTE^TEC SUPE^BRAIN

With UCSD Pascal* FORTRAN, and BASIC

UCSD p-System Includes:operating systenn, editor, filer, library,

Z80 assembler, and docurrjentation.

with Pascal $ 600

with FORTRAN 600 with BASIC 500

VERSION [V.0

THE DATALEX COMPANY

1431 Twelfth Avenue, Son Francisco, OA 94122 Telephone: (415) 665-4467

* UCSD p-System and UCSD Pasca I are trademarks of ttte Regents of the University of California "Trademark of Intertec Data Systems

Circle 114 on Inquiry card.

May 1981 © BYTE Publications Inc

419

Listing 1 continued:

PROCEDURE update; ^AR

DCAT : ARRAY i:DIR„SlZE3 OF CATALOG-RECORDS RNtRECNUMr

PROCEDURE RENAME? -CchanSes name of MASTCAT.DATA to BACKCAT.DATA>

VAR

i:INTEGER?

SPSJSTRJ:NGi:i6Df

VOLyAVOL:VOL_IDf

dir:directoryj

beg:i:n

UNi:TREAD(5rD]:Ri:0:j r2048»2) ?

V0L:=DIRI:03 ♦DIR_V0L_NAME»

SPS i=C0PY(BLANKS f1f7-LENGTH(VOL))?

AVOI...: =CONCAT ( VOL r SPS ) ?

FOR It=l TO DIRC03.NUM_OF_FILES DO

WITH DiRi::]:::i do

IF (DIR_FILE_NAME='MASTCAT.DATA') THEN DIR_FILE_NAME: = ''BACKCAT.DATA' >

UN ITWRITE < 5 r DIRCO] »2048 ».2) ? ENDf •Creri3me>

PROCEDURE WRITEDEX?

■fwrites a file of pointers to the first occurrence of each letter in the alphc

VAR

DEXFILE : FILE OF INDEXARRAY?

BEGIN

REWRITE(DEXFILE rPFILENAME)r DEXFILE":=DEXRAY» PUT(DEXFILE)f CLOSE(DEXFILEfLOCK>» END ?-Cwr i tedex>

PROCEDURE SORT?

•tsorts the directory file in alphabetical order> VAR

I:RECNUMr

DUF:CATALOG-RECORDf -Cholds record during exchan^e>

FLAGJBOOLEANJ •CFALSE if an exchange made during P3ss>

Lkting 1 continued on page 421

Heath®/Zenith Information Bargain

Send $1.00 and receive $9.50 worth of information that will make owning a Heath® or Zenith computer system even better. First, Buss: The Independent Newsletter of Heath Co. Computers will send you a copy of Revision 3 of the Buss Directory. Published in late February with a cover price of $7.50, this revision contains listings of over 100 independent suppliers of hardware and software compatible with Heath® or Zenith systems.

Read continuing coverage of products from independent suppliers in the Buss newsletter that you will also receive. Each issue has new product innovations that could save you a lot of money. You will also see the candid reports from owners as they evaluate the Heath® or Zenith products. Buss has over 3,500 subscribers and enough information to be published every three weeks. The cover price of Buss is $2.00. A subscription for 18 issues (about one year) is $25 ($35 overseas airmail).

Take advantage of this special bargain and receive the Buss Directory, Revision 3 and an issue of the Buss newsletter. Just send one dollar to Buss, 325-B Pennsylvania Ave., S.E., Washington, DC 2Q003, 202/544-0900. Offer good only while supplies last.

420 May 1981 © BYTE Publications Inc

Circle 51 on Inquiry card.

Listing I continued:

BEGIN

U.lRrrELN<'SORTING 'fDRECr' RECORDS')?

REPEAT

flag:=truej

FOR :[:=DREC DOUNTO 2 DO

:i;f (i:icat[:i:].file_.name < dcatci-13«file_name) then

BEG:i:n -CeKchanae roijtine>

BUFJ=DCATCI.l?

i;icATt:i:it=ncATci~i3f DCATi::i-i.i :=BUFf

FI...AO):-=FALSEy ENIiKif> UIRITE< ' , ' ) P UNTIL FLAG?

WRITELNP

wR :i: Ti;;: i... n (' done sort i ng ') j

ENDMIsort:}PROCEDURE OETDIR;

breads directory of update volume and puts it in DCAT> VAR

DIRX:DIRECTORYf UNITNUMfi: INTEGER?

CHBUF : char?

VOL;i^C)L ID?

SPS:STRINGC16:T BL0CKS_USED:0..988?

BEGIN

BL0CKS-.USED: = 10» •Csssumes duplicate directories>

DREC:=0?

MEMCGETDIR' ) ?

repeat

WRITE<'Enter unit number for reouired directory —> ')? READLN(UNITNUM)?

WRITELN

until unitnum in C 4 ♦» 5 J?

UNITREAD(UNITNUMrDIRXC03»2048r2)? -tread directory into array £iIF

IF IORESULT O 0 THEN

BEGIN

WRITELN('Unit not online')? EXIT<CATALOG)?

^ Listing 1 continued on page 422

Bring the computer to your senses

The Soundchaser' computer music system transforms ttie Apple ir* Into an expandoble, professional quality, polyphonic l<eyboard synthesizer and sequencer. Soundchaser's music modules include a 4 octave keyboard housed in on attractively finished wood cabinet complete vs'ith polyphonic interface cord, connector and control software. The synthesizer voice card provides.

3 analog/digital hybrid, studio quality programmable synthesizers. Each synthesizer consists of a wide range, waveform select oscillator, digitally controlled 24 dB/ octave, low pass resonant filter user definable LFO, fully programmable envelope generators, and a digitally controlled amplifier System software Includes a 4 channel seeiuencer vrfilch supports up to 12 syntheslzeisl

Explore Soundchaser's musical horizons. Roy the sounds at your fingertips.

Keyboard: S650.00. 3 Synthesizer voice card: $350.00. Write or coll for details. Dealer Inquiries Invited, (416) 747-0614

AV^^sport

->^DGSIGNS

Soundchaser Is a trademaik of Passport Designs, Inc. Apple Is o registered trademark of Apple Computer, Inc.

Marketing: 60X21061,

Minneapolis, MN 55421

Headauarters: BOX4/8,

La Honda, CA94020

Circle 318 on inquiry card.

May 1981 © BYTE PublicaUoiu Inc 421

Listing I continued:

•Cput VOL in consistent form3t>

■Cmove directory to DCAT>

VOL}=DIRXCO].DIR_VOL_NAMEf BPSt=COPY(BLANKS»1»7-LENGTH(VOL)> t

VOLI=CONCAT<VOLrSPS); FOR .TJ=1 TO DIRXCOn.NUM-OF-FILES DO BEGIN

WITH DIRXCia DO BEGIN

IF I..ENGTH<DIR_FILE_NAME>>0 THEN BEGIN

DRECJ=DREC+1J WITH DCATCDREC3 DO BEGIN

VOL„NAMEJ=-"VOL» FILE..NAMEJ=DIR_FILE_NAME»

BPS t ==COPY < BLANKS r 1 r 15-LENGTH (FILE-NAME) ) i F.i:LH...NAMC:: t =C0NCAT < FILE_NAME f SPS) f F11... E... K :i: N D ? =^ DIR _ F IL. E _ KIN D f FILE_DATE:=DIR..FILE_DATEf FILE_SIZE{=LAST_BL0CK-FIRST_BL0CKJ BLaCKS....USED: =BLOCKS_USED+FILE_SIZE *

i;;:NDKwith>

END K if ].ens3th> ENDwith dir}{> ENDJ-Cfor>

•Ccreate eritr« with name DRECt=DRECl l. f WITH i:iCATrDREC3 DO

FREE.SPACE contsininsi the unused space on the volune>

Listing 1 continued on page 423

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422 May 1981 © BYTE Publications Inc

Circle 452 on inquiry card.

Circle 453 on inquiry card.

Listing 1 continued:

BEGIN

vol NAMEt=V(:)L;

FILE._NAME: ='FREE.SPACE' J

SPS J =COPY(BLANKS f1f15-LENGTH(FILE_NAME))f

filf....name : =concat ( file-name»sps) ?

f.ile....kind: = :i:nfg;

I-■ 11... ie: ... B A T E: i:i :i: r x i: o .:i . i... a s t ... b oot;

F:i:LE...SlZE;=D];RXi:0 3/rOTAL_BLOCKS-BLOCKS_.USEDf ENDKwith> END.«CsSetdir>

PROCEDURE SETDEX;

•Cxf first occursnce of file nsine with BEX as first letter then

put record number in DEXRAY and increment DEX>

beg:i;n

if ncatcnrec:.file_namec1d >= bex

■ChBve we reached or eKceeded the next indej<?> THEN BEBIN

IF nc;ati:nrec:i.file_namei:i.:i :> dex

THEN REPEAT -Cfills dexray to the next valid index>

dexraycdexd;=oj

if dex-'z' then exit(setdex)?

DEXS^^^^SUCCdiEX) 5

UNTIL (ncati::nrec:i,file_nameci3 = deX);

DEXRAYL:DEX;]:=NTOTREC+NRECf if riEX='Z' THEN EXITOETBEX) > DEX;-SUCC<DEX)i END?{:if> END»-Csetdex>

PROCEDURE MERGE?

•(•Tiersles DCAT with OCAT to form NCAT>

VAR

Xi'Yi'Zt 1. ♦ ,33? continue:BOOLEAN?

oovO?d:recnum;

BEG in

DEXJ-'A'r -Cset first match char for index at 'A'>

OI^OREC?

OREC5~15

I) t -■■ I s

■CREMOV is true if volume to be deleted> IF (NOT REMOy) THEN MOL: =BCATn 1 3 . VOL..NAME?

•CBREC+l is 1 more than the number of files in DCAT>

WHILE (D < DREC+1) DO

BEGIN

WITH dcati:d:i do

BEGIN<;with>

IF (FILE-NAME < OCATCORECn,FILE-NAME> THEN Xt--10

ELSE IF (FILE...NAME = OCATCiOREC] . FILE-NAME) THEN X:==20 ELSE XJ=30?

IF (MOI NAME < 0CATC0REC3.V0L_NAME)

THEN Y:=1

ELSE IF <V0L_NAME = OCATCORECD.VOL-NAME)

THEN Y::=:^2 ELSE YJ=3J

z:=x+Yf

1F-<<0REC=0> or (OREOO)) THEN Z: = llf Listing l continued on page 424

May 1981 © BYTE Publicadoiu Inc 423

Listing 1 continued:

CASE Z OF

11»12»13»21

BEGIN <3dd record to NCAT from DCAT>

NREC:=NREC+1> NCATI.:NREC3:=DCATi:D3f

D«=D + .I. > increment D>

URITE( 'ADD ' ,NCATCNREC3.FILE..NAMEM8) r WRITELN(NCATCNRECJ,V0L_NAME;10)

end;

BEGIN -tadd record to NCAT from DCAT>

NRECJ=NREC+1? NCATrWRECD:=DCATCD3r

GREC:=0REC+1j <increment OREO

DJ-D+1 {increment Ei>

END?

BEGIN -Cadd record to NCAT from OCAT>

NREC:=NREC+i; NCATCNREC.1: =0CATC0REC3 J

0RECJ=0REC+3.? -Cincrement OREO

END i

END?-Cease SETDEX* ENDT-<:with> IF (NREC=NLREC) THEN IF (<OREC>OLREC) AND THEN BEGIN

BEGIN <.do not add record to NCAT>

WRITE<'DELETE 'fOCATCOREC].FILE-NAME{18)? Ul RI r E L N (G C A T - C 0 R E C D ♦ V 0 L _ N A M E: 10) J 0REC:=-0REC+1 T -Cincrement OREO

END i

of Z> ■Ccheck.

poniter index>

WRITECATr -CNLREC is the max array size>

(NOT OFILEEND)) -Cif you are out of OCAT Set some more>

READ_OLD_CAT?

o:=oREc; GREc:=i;

ENDKif>

ENDf-Cwhile> -CDCAT is empty>

REPEAT -Caet whats left

continue:=false»

IF (OREC-=:;=0)

THEN FOR 00:=OREC TO 0 DO

IF <OCATCOO:»VOL_NAME THEN BEGIN

of OCAT>

:> VOL)

NRECI=NRE(:;+1 r NCATCNRECII: =0CATC003 i IF (NREC«NLREC) THEN WRITECATf

SETDEXf END-{:then>

else begin

write('delete '»0catc003.file_namej18)f

writeln<ocati:oo3.vol_name: 10)

ENDH:else.>

IF (NOT OFILEEND) THEN BEGIN -Cif you are out of OCAT Set some

READ_OLD_CATf 0:=0RECf ORECJ=i; CONTINUEt=»TRUE? END»-Cif>

UNTIL (NOT CONTINUE)J IF (DEX <'Z')

THEN FOR CHJ=DEX TO 'Z' DO DEXRAYCCH3 {=DEXRAYCPRED(DEX) 3 r Listing i continued on page 425

more>

424 May 1981 © BYTE Publicadoiu he

Listing 1 continued:

done:=true>

WRITECATf WRITEDEX5 E:NDKiiiatch>

BE(3IN-CuFd3te>

REWR.T TE (P r ' CONSOLE : ' ) f IF LOOKUP<OFILENAME) THEN BEGIN

RESET(OCATFILEtOFILENAME)J

CLOSE(OCATFILErPURGE) f - -Cremove old BACKCAT>

ENDJ-Cif>

RENAME? -CMASTCAT ~> BACKCAT>

IF (NOT REMOV)

THEN BEGIN

GETDIRJ

SORT i

FOR RNJ=1 TO DREC DO PRINT_REC0RD<DCATCRN3)f

END»<:Lf> IF LOOKLIP(OFILENAME) THEN BEGIN

RESET(OCATFILE»OFILENAME)i REAn_OLn_CAT? ENrKif> ELSE OREC:=0? REWRITE<NCATFILEfNFILENAME)? NREC:=0?

merge;

close ( dcatfile)

CLOSE(P)?

WRITELNC'BACKCAT CONTAINS 'fOTOTRECf' RECORDS')? WRITELN('MASTCAT CONTAINS 'fNTOTRECr' RECORDS')? CLOSE(NCATFILE»LOCK)? WAIT? END?-Cupd3te>

PROCEDURE SEARCH? VAR

STOP r FOUND:BOOLEAN ? TARlrTAR2:CHAR? start:INTEGERr WILDCARD:0.,16 9 CAT:CATALOG-RECORD ? TARGETrSPS:STRING?

PROCEDURE LONGSEARCH ?

•Csearch used when slphabeticsl pointer eannot "be used > VAR

NJRECNUMf

BEGIN

DELETE(TARGET?1f1)? <remove wildcard char>

writeln(TARGET)?

REPEAT

READ..NEW_CAT?

FOR N{=1 TO NREC DO IF POS(TARGETrNCATCND.FILE_NAME> <> 0

THEN PRINT...REC0RD(NCATCN3) ?

UNTIL (NFILEEND)r CLOSE(NCATFILE> ?

WAIT? Listing 1 continued on page 426

425

Listing 1 continued:

ci..0S)E:(P) 5

f.-.XIT (SEARCH) END r-CI onase8rch>

PROCEDURE SEARCH-FOR-VOLUMEf VAR

BL.KS»SPS:STRINGL7Dr NtRECNUMJ

BEGIN

Bi...Ks: = ' 'i

DELETE<TARGETrPOS(':'fTARGET)fl) ? SPS:=COPY < BLKS y1,7-LENGTH(TARGET)> i TARGET;=CONCAT(TARGETfSPS)5 wr.i.teln(TARGET) ? REPEAT

READ_NEW_CATf

FOR Nt=l TO NREC DO

:i:F (NCATCNn.yOL_NAME=TAR6ET) THEN PRINT-RECORD<NCATCN3) r UNTIL (NFILEEND)f

close(ncatfile)? wait;

CL0SE(P)5 EXIT(SEARCH) ENDp-<;v5e3rch>

BEGIN-Cse3rch>

STOP t =FALSE iFOUND X=FALSE J

REPEAT

WRITE ('ENTER NAME OF FILE TO BE FOUND—> ')* READLN(TARGET)>

IF(LEN6TH(TAR6ET)>16) THEN WRITELN<'NAME TOO LONG ">i UNTIL (LENGTH(TARGET)<=16)f

IF <POS('<'f TARGET) = 1) •€'<' sends output to pri.nter> THEN BEGIN

DELETE<TARGETrlf1)J REURITE(P»'PRINTER:')i

END-<:if> ELSE REWRITE(P,'CONSOLEI')f RESET(NCATFILEfNFILENAME)i

if <pos(': ' ftarget)<>0) then search_f0r_.volumej

wildcard:=pos(tTARget)?

if (wildcard = 1) then longsearchf

if (wildcard > 1) then target:=copy(targetr1fwildcard-1)>

TAR:l.:=TARGETi:i3f -CTARl used to Set pointer from DEXRAY>

IF (WILDCARD <> 2) •<:TAR2 used to end 5e3rch>

THEN TAR2:=«TAR6ETC2D ELSE TAR2:=:'s'f IF (TARl < 'A')

THEN START:=0

ELSE IF (TARl > 'Z')

THEN start:=dexrayi:'Z'3

ELSE START:=DEXRAYCTAR13J SEEK(NCATFILE*START)5 OET(NCATFILE)? REPEAT

"cat:«ncatfile">

IF ((WILDCARD == 0) AND <P08(TARGET»CAT.FILE...NAME) =1))

then begin print..,.rec(:)rd(cat) »

FOUND:=TRUEf END y Listing 1 continued on page 427

426 May 1981 © BYTE PubUcatioiu Inc

Listing 1 continued:

if ((wilricard > 1) and <pos<target»cat.file_nahe) >= d)

then begin pr]:nt.„,record(cat) > found:=truej ENn»

IF <(CAT»FILE-NAMEC1D > TARl ) OR (CAT.FILE_.NAMEi:23 > TAR2)) THEN STOPJ=TRUEJ

GET(NCATFILE)> UNTIL (STOP OR EOF<NCATFILE)>J

IF (NOT FOUND) THEN WRITELN('FILE 'rTARGET*' NOT FOUND')»

CLOSE(NCATFILE)? CLOSE(P)i WAIT ENDKSEARCH>

BEGIN •{:m3iri>

IF ((NOT LOOKUP(NFILENAME)) OR (NOT LOOKUP(PFILENAME))) THEN INITIALIZE? GET_SYS_'viOL(SYSTEMyOLUME) T -trecord system volume name for rebootirisi> DLREC:=MAXREC iOLREC:=MAXREC»NLREC:=MAXREC i READDEXf -Closd the pointer 3rr3y>

REPEAT

REHOVi=FALSEf NFILEEND J =FALSE r OFILEEND:=FALSE rDONE J =FALSE?

NREC:=0 fOREC t=0 fDREC t=01

NTOTREC:=0 iOTOTREC t-0 f

VOLt=»' 'i

REPEAT

WRITE(CHR(CLEARSCREEN))f MEMCMAIN')?

WRITE('CATALOG —> S)e3rch D)ispl3a B)3ckup U)pd3te R)emove Q)uit')? READ(KEYBOARDfCH)>

writeln;

UNTIL (CH IN L'R'» ' r'f'B'f'b'f'U'f'u'f'S'f's'f'D'f'd'f'Q'r'ca']) f CASE CH OF

'U'f'u' t UPDATE*

'S'f's' : SEARCH?

'D'f'd' t DISPLAY?

'R'i.'r' : BEGIN

REMOy:=TRUE? ENTER_VOL_NAME? UPDATE END?-<:c3se of R>

'B'»'b' : BACKUP?

'Q'f'k' J REPEAT

GET....SYS_UOL(TEST) f

IF (TEST==SYSTEMVOLUME)

THEN EXIT(CATALOG)

ELSE WRITELN('INSERT SYSTEM DISK AND PRESS RETURN')? READLN(CH) UNTIL CH='P'?

END ? <.C3sey UNTIL (CH IN C'Q'»'q'D)? END*

May 1981 © BYTE Publlcalioiu Inc 427

BYTE'S Bits

Market Report for Software Writers

The 1981 Software Writers Market lists more than 1800 firms that will market and distribute programs developed by independent software writers. The report outlines the usual procedures you must take to contact one of these firms with information about a program. If a firm deems that a program has market potential, it will enter into an agreement with you, market the software, and either pay you a royalty based on sales or buy the rights to the program for exclusive use.

The 1981 Software Writers Market provides addresses and telephone numbers of key contact people in service bureaus, hardware manufac

turers, mail-order distributors, book publishers, computer magazines, consulting companies, and more than 1500 retail computer stores. It explains how companies market software, what kinds of software they seek, how you are dealt with, royalty rates, and contract details. The price for The 1981 Software Writers Market is $45 (with updates offered).

For complete details, contact Kern Publications, 190 Duck Hill Rd, Duxbury MA 02332, (617) 934-0445.

Computer Literacy Kits for Schools

More than 700 Apple dealers in the US and Canada are participating in the Apple

Seed program, which provides qualifying elementary and high school students with computer-course materials. Under the program, Apple Computer will donate a $500 bonus kit of course materials to junior and senior high schools which qualify as "start-up" schools and which buy a 32 K-byte Apple computer with at least one disk drive. Schools that are initiating computer education curricula and schools that are expanding ongoing computer education programs with additional Apple systems are welcomed under the plan.

The Apple Seed kit contains a computer-literacy program for teachers and a course for students, including tutorial materials in BASIC for classes with up to 25 students. Books on micro

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computers and systems, computer components for informational purposes, computer literacy programs, an Applesoft BASIC tutorial, and an educational-software directory are incorporated within the course materials. Systems must be purchased from an authorized Apple dealer before July 31,1981. The offer is limited to one set of materials per school.

For complete details on the Apple Seed computerliteracy program, contact Apple Computer, 10260 Bandley Dr, Cupertino CA 95014.

New Network System

The COMNET network links customers' terminals or computers nationwide in a 24-hour store-and-forward message service. Messages are sent to domestic or international Telex numbers, or by Mailgram. Data bases, wire-service news bulletins, financial reports, a section for technical questions, and classified ads are available.

Normal access to COMNET is via a 300 bps asynchronous ASCII terminal, using TYMNET. The basic monthly fee is $10, with incremental charges for various services.

To subscribe to COMNET, you must normally have a Visa or a MasterCard account although other credit arrangements can be negotiated. For details on options and service fees, contact Cantlin Communications, 11532 Poes St, Anaheim CA 92804, (714) 530-6693. ■

428 May 1981 © BYTE PubUcaUons Inc

Circle 94 on Inquiry card.

AIM 65. Ihe professional's microcomputer.

Printer, display, full keyboard. Under $500.00.

For professional learning, designing and work, Rockwell's AIM 65 micxocomputer gives you an easy, inexpensive head start.

• 20-coluinn printer and display

• Dual cassette, TTY and general purpose I/Os

• R6502 NMOS microprocessor

• System expansion bus

• Read/write RAM memory

• Prom/ROM expansion sockets

• Self-prompt interactive monitor firmware

• Terminal-style keyboard

• Options include: —Prom Programmer

module —RM 65 standard modules and card cages

For more on AIM 65 and how you can develop programs in assembly language, BASIC, PL/65 or FORTH, write Rockwell International, Electronic Devices Division RC55,P.O. Box 3669, Anaheim, CA 92803. For location of nearest distributor or dealer call 800-854-8099 (in California 800-422-4230).

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circle 353 on inquiry card.

BYTE May 429

Programming Quickies

don't risk

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Printf for the C Function Library

Christopher Kern, 2011 St SW, Apt V-839 Washington DC 20024

One of the most-used functions in the standard Hbrary for the C programming environment is printf, the formatting print function. Printf accepts character, string, and numeric values as arguments and sends them to the standard output (normally the user's console) according to a specified format. It is used both as the main way to provide a program's output to the console and as a way of testing variable values during debugging. Its controlformat string may specify that numerical values be represented in hexadecimal, octal, or decimal notation, that right or left justification be employed, and that arguments be printed in a given field width or restricted to a limited precision.

Although present versions of the BDS C compiler for the 8080 CP/M operating system have the standard printf function, earlier versions had a more primitive version of printf. If you have a version that cannot print numerical data in octal, does not permit precision to be specified to limit the length of a string, and only left justifies, the program shown in listing 1 will add all the standard features and a few new ones.

Except for the features that apply only to floating-point and long nunierical data, this program conforms to the specifications for printf in Kemighan and Ritchie's The C Programming Language (Prentice-Hall, 1978). It is simple to adapt printf to other languages, so long as they permit functions, procedures, and subroutines with a variable number of arguments.

Functions compiled with the BDS C compiler find their arguments along an array of vectors stored at location BASE -I- 0x3f7, where BASE is the base address of the CP/M operating system for the particular machine being used (and "0x3f7" is C's idiosyncratic notation for hexadecimal 3F7). Up to twenty-four arguments are allowed. Because printf doesn't know in advance how many arguments will be needed as interpretation of the control format proceeds, and because the same function-argument vector will be used by subordinate functions called by printf, all the arguments are collected at the outset and stored in local argument array, "localarg[]." This is the one feature of the function that is specific to the BDS compiler. Note that because the control format is passed to printf as a formal parameter, the processing of the re^ maining arguments begins at FARGV -I- 2.

Listing 2 shows a sample run and a demonstration program that exercises printf by printing a series of integers in various notations and by printing a string in various

Text continued on page 434

Mqr 1981 © BYTE Publkatioiu Inc

Circle 113 on Inquiry card.

Programnilng Quickies

Listing 1: This is a program for adding a full-featured printf function to some early versions of C compilers. These earlier versions did not allow the printing of numerical data in octal, and did not permit precision to be specified to limit the length of a string; they allowed only left justification. Two new functions which are called by printf have been added: "Nbase" converts a binary integer into a digit string in the requested radix; "Nspoct" does the same for split octal.

♦defiriE? BASE 0x4200 /* CP/M base address */

♦define FARGV 0x3f7 /% BDS G compiler srsfument vector */

p r :i. n t f ( c o r i I., r o J. ) char *control» •C

char cy ♦pss' rJustifyc sC17.'.l!' zerofillJ

int #3rsSS!' ki- loc3l3r^lI2331» prcisny slen* width?

/* cof*a ariSumerits from function srsfument vector */

for (k « 0» eras BASE + FAR6M + 2? k < 23? ++k» ++3rss)

localarssCkn *3r.^s? arsse = loc3l3r£{?

while (c *control + +)

/* check far conversion specification */

if (c =^ '•'/.' ) C

/* check for various options */

if (<c ~ *control) '-') -C rJustify ~ 0? c == *control++f

6 X

r Just :i. f y " 1 j

if (c =-•=.■: '0')

zerefill ~ 1?

else

zerofill = Of

width ~ 0?

while (isdiait(c ~~ tolower (*cont rol++) )) width ~ 10*width f c - 'O'f

if (c ' . ') -C

prcisn - Of

while (isdi£!it(c ~ tolower (*contrDl + f ))) prcisn •"= 10*prcisn + c - 'O'f

>

else

prcisn ■■■■ 32767 r

/* process conversion characters */

switch <c) •€ case 'b ' {

PS ~ nbase(*ar£{s++f 2i s)f bre3k f *

PS = nbase(*3r^sf+r 8f s)f

Listing 1 continued on page 432

May 1981 © BYTE PubUeatknu bic 431

PFogrammlng Oulcklm.

Listing 1 continued:

case 'd't

if (*3r^s < 0) <.

PS = rib3se<-*3ras++ip lOr s)i

>

else

PS = nbase<*3ras++» 10? s)J

break»

PS «= nb3se(*3rsls++)' lOt s)» break»

PS « rib3se<*3rsis++» 16t s>r

break?

■ ♦ *

PS = nspoct<*3r£is++» s)J

breakf

■ ♦

break?

■ ♦ *

c « *ar*gs++>

default J

*(PS - S) =

>

k = 5trlen(F's) ?

slen = k > prcisn ? prcisn * ki

if <rJustif«)

while (width-- > slen) if (zerofill)

putchsr('0')J

else

for <k = Ir *ps %% k <■- prcisn? ++k) putch3r(*ps++)i

if ( ! rviustlfy)

while (width-— > slen) pgtcharC ')J

>

else

pijtchar<c)J

nb3se(nj' baser s) unsigned ns- base? char *s» C

int df

*(s 16) '\0' ?

if (n ™™ 0) Listing 1 continued on page 433

432 May USl © BYTE PublkaUoiu Itie

Programming Quickies

Listing 1 continued:

else

while (n > 0) C

*—s = (d " nXb3se) + (d < 10 ? '0' t 55) J n /=s base J

>

return s?

unsigned ni char sC3» {

int d? d = 16384? char JftpsJ ps = s?

while (d > 0) <

*ps}+ = n/d + '0'? n %== d?

if <fj i=« 256) C d =^ 64!!

>

els©

d /= 8?

>

*F'S == '\0'? return st

Listing 2: Listing and sample run of a demotistration program which exercises the printf function. A>TYPE F-'RINTX.C

m3in()

una i .<.i!ned i »

char *strinaf strin<.5 "helloi' world" r

for <i :l? i 163841! i 2) <.

printf ("dec: X^d octi 7.60 sploct; %a

printf ("he;;: %4;{ bin J X016b\n"r i i- i)J

>

"f if xt i>»

printf( "\n")?

printf<";%10s:\n"f string)i :%-10st\n"y string) J%20s;\n"y strinrf)y :Z-20s:\n"y strinsa)

printf( printf( printf( printf(

X'/.20*10sX\r\* t string)?

Listing! continued on page 434

May 1981 © BYTE Publications Inc 433

Programming QiilckiM

Listing 2 continued:

printf< p-rintf (

>

J%-20.10st\ri"» string)? J%*10s:\ri* r string)?

A>PRINTX

dec *

1

oct-;

1

S P 1 o c t

000.001

hex;

1

b i ri J

0000000000000001

dec*

o

2

S P1 Oct

000»002

hex;

2

b i ri

0000000000000010

dec J

4

n r*- + ;

4

<5 P 1 O C t i

000♦004

he;-;;

4

bin

0000000000000100

dec {

8

oct;

10

<5Ploct!

000.010

hex;

8

b i fi)

0000000000001000

dec:

16

oct;

20

sploct i

000.020

hex;

10

b i n!

0000000000010000

dec t

32

oct;

40

spIoct!

000*040

hex;

20

bin!

0000000000100000

dec;

64

oct;

100

isploct {

000.100

hex *

40

bin.

0000000001000000

dec;

.1.23

oct;

200

S P1 o c t J

000.200

hex;

80

b i ri'

0000000010000000

dec;

256

oct;

400

sploct <

t 001.000

hex;

100

bin

[ 0000000100000000

dec*

512

oct •

1000

sploct

; 002.000

hex *

200

b i n

i 0000001000000000

dec;

1024

oct;

2000

sploct

; 004,000

hex;

400

b i n

; 0000010000000000

dec;

2048

oct;

4000

sploct

! 010.000

hex;

800

bin

! 0000100000000000

dec*

4096

Oct;

10000

sp.loct

! 020.000

hex *

1000

bin

\ 0001000000000000

dec*

8192

oct;

20000

sploct

; 040,000

hex;

2000

b i n

; 0010000000000000

dec; 16384

oct;

40000

sploct

; 100.000

hex;

4000

bin

; 0100000000000000

;hei:io

y world;

; hello

f world;

*

hello ?

world*

; hello

f world

; hello

» wor

hel lo

y wor;

Jhello

» wor

♦

A>

Text continued from page 430:

combinations of justification, field width, and precision (the ":" serves to delimit the field). Calls to printf take the fonn:

printf (control, argument 1, argument 2, ... )

where "control" is a format string composed of text interspersed with conversion specifications—one for each argument.

Each conversion specification begins with the "%"

character and ends with a conversion character indicating the format to be used in printing the corresponding argument (character, string, or number). The standard conversion characters "d" (decimal notation), "u" (unsigned decimal), "o" (octal), "x" (hexadecimal), "c" (character), and "s" (string), are supported. I have added two others not specified in Kemighan and Ritchie's book: "b" (binary notation), which is especially useful for debugging programs that use bitwise logical operators, and "q" (split octal), because the front panel of my Heath H-8 computer has a split-octal display.

A number of options may be specified between the "%" character, which introduces the conversion specification, and the conversion character. A minus sign (—) indicates that left justification (instead of the default

right justification) is requested. A digit string indicates the field width; a number that fails to fill the width will be padded on the left or right, as necessary. If the field width is specified with a leading zero, a right-justified number will be padded with zeros instead of blanks, so an 8-bit binary number can be printed as 00100101 instead of 100101. A period followed by another digit string indicates the precision, the maximum field width in which an argument is to be printed; this is primarily useful for truncating strings that exceed the permissible line length.

This version of printf uses four other standard C library functions: "tolower(character)," which converts its argument to lowercase if it isn't lowercase already; "isdigit(character)," which returns true (not zero) if its argument is a digit and false (zero) otherwise; "putchar (character)," which outputs a character to the console; and "strlen(pointer to string)," which returns the length of the string its argument points to.

Two other functions, called by printf and independently useful additions to the standard library, are also included (see listing 1). "Nbase(number, base, pointer to array in which to store result)" converts a binary integer to a digit string of the requested number base. "Nspoct (number, string pointer)" does the same (with leading zeros, and a "." separating the 2 bytes) for the special case of split octal. ■

434 May 1981 © BYTE PubUcaUons Inc

Numerical Methods in Data Analysis

Toan C Nguyen 818 Gaviota Ave Long Beach CA 90813

In engineering research and design work, it is often

necessary to determine analytically from a given set of n pairs of discrete data a function which best represents the dependence of one parameter (X) upon the other (Y). Moreover, other characteristics of the obtained function represent this dependence, such as information about its stationary (maximum or minimum) point and its roots, that is, values of X which make Y equal to zero.

Calling on our mathematical background, we know that most continuous functions with defined derivatives may be expressed in a form of a polynomial:

Y = flo + fliX + a2X' + a,X' + . . . + a^X"

where m is the degree of the polynomial and ao, Oi,. . . , a„ are the coefficients.

For a given set of n pairs of data, there is usually a polynomial of degree m with corresponding coefficients Oo, ai, . . . , dm which will approximately describe the general continuous relationship between the two parameters X and Y. The error incurred in obtaining this polynomial will usually be minimal when m is sufficiently large and useful values of Xs and Ys are in the neighborhood of the range [(Xi, Yi),(X„, YJ] where Xi<Xz< . . . <X..

By definition, the stationary point of a function is the point at which the dependent parameter Y attains a local maximum or nmiimum value. This stationary value of the variable X may be obtained by solving the equation Y' = 0, or:

fli + 2B2X -I- SflaX^ + . . . + mfl„X"-' = 0

The determination of function Y = f(X) may be done by curve fitting, which requires solving a large set of

About the Author

Toan C Nguyen is a registered professional engineer in the state of California and a member of the American Society of Mechanical Engineers. He has a master's degree in mechanical engineering from the University of Southern California,

Mr Nguyen has devoted much of his time to the application of computer programming in solving engineering problems. He is presently a senior engineer with the Pipe Hanger Division of ITT Grinnell Corporation.

simultaneous linear equations. The Gauss-Jordan

elimination method may be utilized to solve these simultaneous equations. Once the function f(X) is obtained, the values of quantity X for which f(X) equals zero may be calculated by the Newton-Raphson method, which is one of the various numerical methods for obtaining the roots of a continuous differentiable function.

Because many calculations will be performed repetitively, these tasks will be conveniently handled by a digital computer utilizing its ability for high-speed calculations. A scientific high-level language, such as FORTRAN IV, is a suitable language for the development of a computer program for use in this application.

This article will briefly review the principle of curve fitting, the Gauss-Jordan elimination technique, and the Newton-Raphson method. Included is a computer program written in FORTRAN IV with corresponding flowchart and explanations. Examples of practical engineering problems in different fields are also presented.

Curve Fitting: Method of Least Squares

In fitting a curve through the points representing (Xi,YO, . . . , (X„,YJ, we employ a mathematical principle that yields a best-fit curve: the method of least squares. This method utilizes the laws of probability in obtaining the most probable values for a given set of observations of independent and dependent parameters. According to this method, the coefficients of a polynomial of degree m may be determined from the following m + 1 simultaneous equations:

Cuflo + Cufli + Ciaflz + . . . + Ci[„+i)fl„ = bi

CziUo + C22«l + CziCll + . . . + C2[m+ll Am = ^2

. . (1)

where:

b, ^Ei'-'y

May 19B1 © BYTE PublicaUoiu Inc 435

(a)

Independent parameter

(b)

1 2 Independent parameter

(c)

u <u

e 3

a!

P.2

•p C

0) 0)

°0

t;-^

^'^^^

1

Independent parameter

Figure 1: A representation of the least-squares curve-fitting method. In (a) we see the first-degree curve, which is not acceptable because the uncertainty envelope does not contain all the data points. The figure in (b) shows the second-degree curve, which is not acceptable for the same reason as (a). The third-degree curve is illustrated in figure (c). Here we can observe that the uncertainty envelope does contain all the data points and is, therefore, the desired degree of the least-squares polynomial.

and the summations Eare performed from 1 to n, the number of pairs of data.

Most engineering data is taken with an uncertainty margin. This margin may be expressed as an absolute deviation or as a relative deviation, such as 50 ± 0.5 inches and 50 inches ±1%, respectively. Therefore, when the uncertainty envelope has the most probable least-squares curve as its center line, it also has to cover all the given data points. This condition is illustrated in figure 1.

We usually start with a least-squares equation of relatively low degree and then chedc to see if all data

points fall inside the uncertainty envelope before proceeding to the next higher degree least-squares equation. The process will continue until the uncertainty requirements are satisfied.

Gauss-Jordan Elimination Method

After all the summations of the set of simultaneous equations in equation (1) are calculated, our next step is to solve the set of simultaneous equations for «o, «i, . . . , a„. Although there are numerous techniques to handle this task, the method presented here is the Gauss-Jordan elimination method. Th.e reason for using this method in

436 May 1981 © BYTE PublicaUons Inc

Variable Definitions

FORTRAN Variable

A (M)

C (1.1)

ERR ERROR

ERT EROOT

ESTN ESTATN

I

ICHANG

ICONTI

IROOT

ISTATN

lUNCER

J K

KPLUS LROOT

LSTAT

M

MDEG

MDEGRE

MMINU5

MPLUSl

MPLUS2

Definition

a„, the mth coefficient of a least-squares

polynomial

Cij, element at ith row and jth column of the augmented matrix of the set of m + 1 simultaneous equations to be solved for

\f(XJ/f'(XJ I, absolute value of the nth incurring error in the determination ofX fof' which f(X)'=0. by 'Netjoton-Raphson method

e, general term for allowable error- (at

the beginning of the iteration process) or resulting error (at the end of the process) in the determination of Xr=o and Xsta, used in subroutine NEWRAP ey,o, allowable error in the determination of Xy=o

Error in the determination of Xr=o (before calling subroutine NEWRAP: allowable error; after: resulting error) esTA, allowable error in the determination of XsTA

Error in the determination of Xsta (before calling subroutine NEWRAP: allowable error; after: resulting error) DO loop index

String input specifying the name of the particular variable of which the value is to be changed

String input (YES or NO) to continue or to stop the process of changing values of some variables

Code indicating whether the calculation ofXy^ is needed or not (0: No, 1: Yes) Code indicating whether the calculation of Xsta is needed or not (0: No, 1: Yes) Code indicating whether the uncertainty is entered as absolute or relative value (0: absolute, 1: relative) DO loop index DO loop index K+1

ROOT, string variable for printout purpose

STATN, string variable for printout

purpose

DO loop index

m, degree of the least-squares polynomial to be fitted through the given set of

data, used as the first trial Incrementing m, starting from MDEG to a maximum of 10

M-1

MDEGRE+1 MDEGRE+2

N DO loop index for loop which calculates

root off(X)=^0 . NCODE Code used before subroutine NEWRAP is called to indicate whether the calculation will be for Xr=o or Xsta (1: for Xy.o, 2; for Xsta)

NEWTON Code used in subroutine NEWRAP having the same function as NCODE; its value is transmitted from main program

NITERA Before the iteration process: maximum allowable number of iterations, transmitted from main program; after the iteration process: actual number of iterations used to obtain the required accuracy e (this new value will be returned to main program)

NMINUS N-J.

NPAIRS Number of pairs of data NPLUS N+1 .

NRERUN Code to direct the calculation flow to the

beginning of the program (NRERUN=1)

or only to the portion computing Xy»o

and Xsta (NRERUN=0) NROOT Similar to NITERA, except that it is in

main program and is used primarily for

calculating Xr^o NSTATN Similar to NITERA, except that it is in

main program and is used primarily for

calculating Xsta SUM Es, summations representing bi or Cy

UNCERT Uncertainty margin, may be entered as

absolute or relative value UNMARG Uncertainty margin, calculated from the

given UNCERT and lUNCER, and is

converted into an absolute value X(N) Xs, data entered as independent

parameters

XO Before the iteration process: initial ap

proximation of X„, transmitted from main program; after the iteration process: obtained value ofX„ which satisfies the required accuracy (this new value will be returned to main program)

XS(N) X„, nth value of iterated X in Newton

Raphson formula

XRTl Similar to XO, except that it is in main

program and is used primarily for calculating Xy^

XSTNl Similar to XO, except that it is in main program and is used primarily for calculating Xsta

Y(N) Ys, data entered as dependent

parameters

YDEN f'(XJ, denominator value in Newton

Raphson formula YNUM f(XJ, numerator value in Newton

Raphson formula YOFX Y(X), value of Y

given value of X

corresponding to a

U*y 1981 © BYTE Publications Inc 437

Listing 1: FORTRAN listing of the program CURFIT that solves the least-squares polynomial for the entered pairs ofdataX(n) and Y(n). Some language features used here differ from standard FORTRAN.

00100 PROGRAM CURFIT (INPUTiOUTPUT)

00110 DIMENSION X<100)fY(1001•«<tl)iCI11■12)

00120 caHH0H/EIL0CK/«>HPLUSl>HPLUS2

00130««*X«

00M0t«««» DATA STATEMENTS 00150«t***

00140 OATH NPAIRS.dOEG.IUNCER.UNCERTiIROOT.XRTl.ERT.ISTATNiXSTHliESTN/

00170tlO>l>Oi.lrli-l.t>001>l'0.>>001

OOlSOt/tX/

00190+-2. t-l,5i-l. .0. >1. <2..2.5i3. i!. 00200(-/tY/

00210'f-25.l.-4.9i3.l>S.>-4.9>-21.>-25.i-25.1i-7.>*S.

00220'!'/

00230*****

00240***** FORMAT STATEMENTS 00250*****

00240 10 FORMAT <//2Xil2HTHE DESIRED iI2i47H-TH DECREE LEAST-SDUARES EQUATION HA 00270tS A FORM OF ./SX■HHV(X) = SUM OF .12r1?H-TERMS OF A(1)I.5X,12HI = 0.1

00280+....1 .i2.//20X.lHI.!X.4HA(I)./19X>3H-—.2X.BH ./I

00290 20 FORMAT (19X>I2t3X>FS.3)

00300 30 FORMAT (//2X,4HAFTER ,I2.35H ITERATIONS. THE 06TSINEB UALUE OF .n4.3H I OOJlOtS .Fa.3.7H GIUING./12HAN ERROR OF . FO . 5 . 2X , 33HIF fOU UANT TO TRY »EU UALUE 00320tS OF .Ai.UH AND ERROR../45HENTER THEM IN THAT ORHERI IF NOT. ENTER 0..0.) 00330 40 FORMAT (/2X.4HAFTER .I2.35H ITERATIONS. THE OBTAINED UALUE OF .A6,4H IS 00340> iF8.3)

00350 50 FORMAT <//2X.*riO YOU UANT TO CHANGE ANY yARIABLES AMONG. MDEG* UNCERT. E 00340tRT. ESTN.«./1X>«XRT1, XSTNl. lUNCER. IROOT. ISTATN ? (YES OR NO)*) 00370 40 FORMAT </2X.«ENTER THE VARIABLE TO BE CHANOED <HIT RETURN)! AND THEN IT 00380tS NEU VALUE*)

00390 70 FORMAT </2Xi*ANY MORE VARIABLES TO BE CHANGED »*)

00400 80 FORMAT (//2X.»ALTHOUOH A «rI2.»-TH DEOREE LEAST SOUARES CURVE HAS BEEN 004J0'tFITTED THROUGH THE*./1X.«DIVEN SET OF DATA. THE SfECIFIEIi UNCERTAINTY MARO 004204'IN IS NOT YET SATISFIED*)

00430 90 FORMAT <2X.«THE CORRESPONDING,VALUE OF YIXSTATN) IS J.FB.3)

00440 100 FORMAT <//SX>«THE SPECIFIED DEOREE OF THE LEAST SOUARES EQUATION IS =

00450* THE NUMBER*./lXi»OF PAIRS OF DATA. REENTER MDEG « NPAIRS )«)

00440*****

00470***** DEFINITIONS OF SOME VARIABLES

004GO*****

00490 LROOT>SHXR00T

00500 LSTAT>4HXSTATN

OOSIO 110 MDE0RE>nDE0

OOS20 112 EROOT-ERT

00530 ESTATN-ESTN

00540 115 IF (HDEGRE.LT.NPAIliB) 00 TO 120

00550 PRINT 100

00540 READ.MDEG

00570 GO TO 110

00580 120 NRD0T = NSTATN=20

00590 MPLUS1=MDE6RE+1

00400 HPLUS2-HDEGRE4'2

00410*****

00420***** DETERMINATION OF ALL SUHHATIONG IN THE SET OF Mi SIMULTANEOUS EONS. 00430*****

00440 DO 210 I'l.HPLUSt 00450 DO 200 J-1.MPLU82 00440 SUH..O.

00670 DO 220 N=l.NPAIRS

00480 IF (J.NE.MPLUS2) SUM=5UMtX(N)**(I+J-2>

00490 IF (J.E0.MPLUS2) SUM=SUM'^Y (N ) «X (N > *» (I-1 >

00700 220 CONTINUE

00710 C(I.J>>SUH

00720 200 CONTINUE

00730 210 CONTINUE

00740*****

00750***** DETERMINATION OF COEF. AO.....AH OF THE M'-TH DEGREE LEAST-SQUARES

00740***** POLYNOMIAL BY GAUSS-JORDAN ELIMINATION METHOD

00770*****

00780 DO 330 K=1.HPLUS1

00790 KPLUS=K'H

OOSOO DO 300 J'KPLUS.HPLUS2

OOBIO C<K>J)°C(K>J)/C<KrK)

O0S2O 300 CONTINUE

00B30 DO 320 I-l.MPLUSl

00840 IF (I.EQ.Kl 00 TO 320

00850 DO 310 J°KPLUS.HPLUS3

00840 C<I.J)>C(I.J)-C(IiK>*C(KiJ)

00870 310 CONTINUE

00860 320 CONTINUE

00890 330 CONTINUE

00900***** ^ 00910***** CHECK FOR UNCERTAINTY REQUIREHENTS 00920*****

00930 DO 410 N'l.NPAIRS

00940 YOFX-0.

00950 DO 400 H..1.HPLUS1

00940 A(MI-C<M.NPLUS2>

00970 YOFX"YOFX't'A<M>«X<N)«*IM-l )

00980 400 CONTINUE

00990 IF <IUNCER.NE.n UNMAR6 » UNCERT

01000 IF <IUNCER.E0.1> UNMARG - ABS<UNCERT»YOFX)

01010 IF CA8S(YtN>-Y0FX>.LE.UNMARS) GO TO 410

01020 MDEGRE = MDEGREf I

01030 IF (HDEGRE.LT,NF'AIR8.ANn.MDEGRE.LE.10) GO TO 112

01040 MDEGRE=HDEGRE-1

01050 PRINT 80.HDEGRE

01040 op TO 700

01070 410 CONTINUE

01080*.****

01096»***» PRINT-OUT OF COEF. AO.... .AM OF THE OBTAINED M-TH DEGREE 01100«»««t . LEAST SOUARES EQUATION

OHIO*****

01120 PRINT lO.MDEGRE.MPLUSl.HDEGRE

01130 DO 500 M=1.MPLUS1

01140 MMINUS=M-1

01150 PRINT 20.HHINUS.A(M)

01140 500 CONTINUE

01170*****

01180***** CALCULATION OF VALUES OF XROOT OR XSIA 01190*****

01200 IF (MDEGRE.EO.1) IRO0T"O

01210 550 IF ( IROOT.NE. 1 .AND.ISTATN.NE.l) GO TO 700

01220 IF (IRDOT.NE.l) GO TO 420 01230 600 NCODE = 1

01240 CALL NEWRAP (XRT1.EROOT.NROOT.NCODE)

01250 IF CNR0DT.LT.20) 00 TO 410

01260 PRINT 30.NROOT.LROOT.XRTl.EROOT,IROOT

01270 READ.XRTl.ERT

012B0 EROOT=ERT

01290 IF (XRTl.EO.O..AND.EROOT.EO.O.) GO TO 420 01300 GO TO 400

01310 410 PRINT 4O.NR0OTiLRO0T.XRTl 01320 420 IF (ISTATN.NE.l) GO TO 700 01330 430 NCODE = 2

01340 CALL NEURAP <XSTNI.ESTATNiNSTATN.NCUDEI

01350 IF [NSTATN.LT.20) GO TO 440

01360 PRINT 30.NSTATN.LSTBT.XSTNl.ESTATN.LSTAT

01370 READ.XSTNl.ESTN 01380 ESTATN^ESiTH

01390 IF ( XSil N 1 . CO . 0. , AND. FSTATN.EO.O. I RU 10 700 01400 GO TO 630

01410 440 PRINT 40.NSTATN.LSTAr.XSTNI

01420 Y0FX"0.

01430 DO 650 M-l.MPLUSl

01440 Y0FX.Y0FXtC(M.MPLUS2)»XSTNl««(H-l: 01450 650 CONTINUE 01460 PRINT 90.Y0FX 01470««*«*

014S0»»*«« CHANGING VALUES OF SOME VARIABLEl!

01490*****

01500 700 PRINT 50

01510 READ.ICONII

01S20 IF (ICaNTI.E0.2HN0) GO TO 800

01530 NRERUN=0

01540 710 PRINT 60 0 1550 READ . 1 CHANIi

01560 IF (ICHANG.EO.4HMDFG) READ.MDEG 01570 IF ( ICHANG . i:n . fHIINCERT ) REA[i.UNCERT 01580 IF ( I CHANI', iZO . "HiM^ I ) RE.^Ii.FRT 01590 IF ( ICHANG . Efi ,'1H1^". rW ) REAIlTSTN 01400 IF CICHANG.EQ.4HXRU} READ.XRTl 01410 IF (ICHANG,EO.SHXSTNl) READ.XSTNl 01420 IF (ICHANG.ED.4HIUNCER1 READ.IUNCER 01430 IF (ICHANG.EO.SHIRQOTI READ.IROOT 01440 IF (ICHANG.EQ.4HISrATN) BEAD.JStATN 01450 NRO0T=NSTATN=2O 01440 ER00T=ERT 01470 ESTATN=ESTN

OliBO IF <ICHANG.EQ.4HHDE3.OR.ICHAN0.EG.4HUNCERT.OR.ICHANC.EO.IUNCER) NRERUN^

01690 FRINT 70 01700 READ.ICONTI

01710 IF (ICONTI .E0.3HYES) GO TO 710

01720 IF (NRERUN.EG.l) 00 TO 110

01730 GO TO 550

01740 800 STOP

017S0 END

01760*****

01770***** CALCULATION OF ROOT OF F(X)=0.. AT THE NEIGHBORHOOD OF X=XO,

01780***** DY NEUTON-RAPHSON HETHOD

01790*****

OIBOO SUDROUTINE NEURAP (XO,ERROR,NITERA,NEUTON) 01810 DIMENSION XS(21).A(li) 01820 C0HM0N/BL'0CK/A.MPLUS1.MPLUS2 01830 XS(1)=X0

01S40 IF (XO.EO.O.) XS(ll-XOc,0001

01S50 DO 950 N'l.NITERA

01840 NPLUS'Ntl

01870 NHINU3>N-1

O1880 910 YNUM-YDEN>0.

01890 DO 930 I = 1.MPLUS1

01900 IF (NEUTON.CO,2) GO TO 920

01910 YNUH=YNUH*A(I)»XS(N)»»(I-1)

01920 YIiEN=YDEN+(I-l)«A(I)»XS(N)«»(I-2)

01930 GO TO 930

01940 920 YNUH=YNUM'KI-l)«A(I)«XS(N)*«(I-2)

01950 YDEN=YDENt(I-l)*(I-2)»A(I)«XS<N)»«(I-3)

01940 930 CONTINUE

01970 IF (YDEN.NE.0.1 SO TO 940

01980 XS(N)=(XS(N)+XS(NMINUS))/2.

01990 GO TO 910

02000 940 ERR = ABS(YNUM/YDEH)

02010 IF (ERR.LE.ERROR) SO TO 940

02020 XS{NPLUS)=XS(N)-YMU«/YDEN

02030 950 CONTINUE

02040 XO=XS(NPLUS)

02050 GO TO 970

02040 960 XO=XS(N)-YNUH/yDEN

02070 970 ERROR^ERR

02080 NITERA-N

02090 RETURN

02100 END

READY.

stead of Cramer's rule is that it proves to be a simpler and a less time-consuming procedure, especially when the system to be solved has more than three simultaneous linear equations.

This method is a combination of the Gaussian forward and backward eliminations. The forward, elimination consists of the following steps:

• Elimination of ao from the second and succeeding equations by dividing the first equation by Cu; multiplying the modified equation respectively by C21, C31, . . . , C[„+i]i;

and then subtracting the obtained equations respectively from the second, third, . . . , (m+l)th equations. The resulting set of equations is of the form:

flo + C'i2fll -I- C'i3a2 -I- ... -I- Ci[„+ii Om = b'l C22«l + C23fl2 + . . . + C2[m4.I] «». = ^2

. (2)

C[iii4.1J2fl!l "f" . . . + C[»n,i] [m4'l]<2m — b[m*l}

438 May 1981 ® BYTE Publicalions Inc

• Elimination of Oi from the third and succeeding equations by dividing the second equation in the set of equations in (2) by c^; multiplying the modified equation respectively by c'32,Ci2, ■ ■ ■ , c[„+i,2; and then subtracting the obtained equations respectively from the third, fourth, . . . , (m + l)ih equations. •The elimination process continues until the system is of the form:

ao + ci2fli + claflj -t

■ "I" C i[m+l]flm — b '\

. (3)

-(m+l) „ '-[m+1] [m+lj Mm

The backward substitution process may now be used to find the values for all a, in the reverse order. The value

of a„ is calculated from the last equation in equation set (3) and is substituted in the next-to-last equation to solve for fl„-i, etc.

In the Gauss-Jordan elimination method, the last procedure (backward substitution process) is replaced by the elimination of a,-, starting from the second step, not only from the Ci-|-2)th and succeeding equations, as previously mentioned, but also from all preceding equations, (from the first to the ith equation). Thus, at the end of the process, the final set of equations is of the form:

«o = b'l

(4)

«m = b[Zll\

As we notice, the values of ao, a-i, . . . ,a„ are obtained

f(x)

Figure 2: An example of a function f(X) that is not monotonically increasing or decreasing. This is clearly an undesirable situation for application of the Newton-Raphsoti method as the successive approximations diverge rather than converge on the desired root of the equation.

directly from equation set {A) as b'l, bl, . . . , b\ZXi\.

One remark about this method is that the values Cu, c'22, . . . must be different from zero to make all divisions meaningful. If this is not the case for some equations, these equations may be rearranged with others which have nonzero values of c.

Newton-Raphson Method

So far, utilizing the preceding techniques, we are able to determine for a given set of n pairs of data, a best-fit curve which is represented by the polynomial:

Y = ao + aiX + a2X' + . . . + aj(r

The roots of Y(Xj =0 and the X-coordinates of the stationary points (referred to as X«.) are determined by the following equations:

Y = flo + fliX -I- fljX^ -IY' = fli + 2fl2X -I- JfljX^ H

+ fl^X" = 0 + mfl„X'"-' = 0

As long as YfXj has first and second defined derivatives and the equations Y(X) = 0 and Y'{X) = 0 are solvable, the values of X>-=o and Xsta may be calculated by using the well-known Newton-Raphson method.

This is an iteration process in which successive approximations are made in accordance with the formula

= X„

/fXJ /'(XJ

n = 1,2,

For rapid convergence, the initial approximation Xo should be in the neighborhood of the desired root of the equation f{X) and such that f'{X) ^ 0. This value of Xo may be obtained with the aid of a rough sketch or tabulation of f{X) versus X.

The iteration process continues with converging X,+i until the required accuracy e is obtained, that is

I X,« - X„ I < e or I f(XJ/f'(XJ \ < e

When f(X) is not a monotonically increasing or decreasing function, or when there is a point of inflection in the interval IXxiXi], the Newton-Raphson method may cause difficulties. In this may tend to diverge or

/'CXJ may happen to be very small or equal to zero, as illustrated in figure 2. A new value of X„ should be reassigned to avoid additional unnecessary iterations or to make f (XJ ^ 0. This may be accomplished by taking the average of that particular X„ and the previous value X„.i (that is, (X„)„.„ = fX„ + X„.J/2).

Application of this method to our problem yields:

/V \ — r\- \ — Y[(Xr-o)n] , Y'[(Xr.o)J

,y , ('Y ) — Y'[(Xsta)J ,

Y'KXstaKJ

Y[(Xy^)„j Y'l(Xy.o)n}

Y'KXstaU

Computer Program

The program is written in an interactive manner for use with a timesharing system. To provide flexibility and ease of execution, some of the variables of the program

May 1981 © BYTE PublicaUora Inc 439

Lbting 2: Sample execution of the program CURFIT.

001 .'Ol !<)» 1 .0» . 1 . ] . - ] . * .001»1»0. » .001 OOlVOI - :j. . 1 .Sr-1 . ,0. , 1 . ,2. .2.5.3. .1. .5. 002101-2'J.1,-6.9.3.1.5. r-A .9,-21 . »-25. .-2S. 1.-7. . 45.

RUN

PROORAM CURFIT

THE IiESiriEIi 3-TH y(X) = SUM OF

AFTER 1 ITERATIONS. THE OBTAINED VALUE OF XROOT IS -1.19S

AFTER 1 ITERATIONS, THE OBTAIMEII VALUE OF XSTATN IS -.422 THE CORRESPONDlNB VALUE OF Y<XSTATN) IS

DO YOU WANT TO CHANBE ANY VARIABLES AMONO MDEO. UNCERT. ERT, ESTN, XRTl, XSTNl. lUNCER, IRODT. ISTATN ? (YES OR NO) ? YES

ENTER THE VARIABLE TO EE CHANBED (HIT RETURN), AND THEN ITS NEW VALUE 7 i<RTl T 0.

ANY MORE VARIABLES TO BE GHAN6ED t ? YES

ENTER THE VARIABLE TO BE CHANGED (HIT RETURN), AND THEN ITS NEW VALUE T XSTNl T 2.S

ANY MORE VARIABLES TO BE CHANEEB T ? NO

AFTER 4 ITERATIONS, THE OBTAINED VALUE OF XRDDT IS .504

AFTER 3 ITERATIONS, THE OBTAINED VALUE OF XSTATN IS 2.759 THE CORRESPONDING VALUE OF YCXSTATN) IS -2S.i52?

DO YOU UANT TO CHANGE ANY VARIABLES AMONG MDEG. UNCERT, ERT, ESTN, XRTl, XSTNl, lUNCER, IROOT, ISTATN T (YES OR NO) ? YES

ENTER THE VARIABLE TO BE CHANGED (HIT RETURN), AND THEN ITS NEW VALUE ? XRTl T 4.

ANV htlRE VARIABLES TO BE CHANGED ? ? Nil

AFILR J ITERr^TIONS, THE OBTAINED VALUE OF XROOT IS 4.194

AFTER 1 ITEHHriONS. THE OBTAINED VALUE DF XSTATN IS 2.759 THE COHRESFIlHtilNG VALUE OF Y < XGTn I N ) IS ■ . 629

lia YOU UANT TO CHflNOE AMY VARIABLES AMONG MDEG, UNCERT. ERT. ESTN. XRTl. XSTNl, lUNCER, IROOT, ISTATN T (YES OR NO) ? NO

a I OP

may be modified directly at the terminal in response to those questions printed by the program (see listing 2).

General Features

The program allows the user to:

• Enter up to 100 pairs of data.

•Enter the tmcertainty margin as an absolute or relative value.

• Specify the magnitudes of the accuracy margins eyro and tsTA required in the calculation of X^^o and Xsta ■

• Detennine the least-squares polynomial and the values of Xr=o and Xsta ■

• Initialize the iteration for finding the least-squares polynomial with any degree which, in the user's opinion, may be the desired one. This option eliminates unnecessary calculations resulting from the choice of the first degree as the initial trial.

• Modify information or values of variables after the completion of the first run. These variables include the lowest desired degree of the least-squares polynomial m, the uncertainty margin, the initially guessed values of Xyi.0 and of the abscissa of the stationary point Xsta (this

Listing 3: Application of the program CURFIT to a chemical engineering problem.

00170+6,2,1, .005,0,0. ,0. ,0,0. ,0,

00190+S.,10.,20.,30.,40.,45.

00210+18.24,18.56,19.03,19,-la, 19.74,19.89

RUN

-SQUARES EQUATION HAS A FORM UF (I)«X**I I = 0,1...., 2

HO YOU UANT TU CHANGE ANY VARIABLES AMONG MPEG. UNCERT, ERT, ESTN, XRTl. XSTNl, lUNCER- IROOT, ISTATN ? (YES OR NB) rES

ENTER THE VARIABLE TO EE CHANGED (HIT RETURN), AND THEN ITS NEU VALUE ? UNCERT . T .0 03

ANY MORE VARIABLES TO BE CHANGED ? 7 ND

THE LiESIRED 2-III DEGREE LEAST-SrillAREG EHUflllON HAS A FORM OF Y(X) = SUM OF 3-TERMS OF A(I)«X««I 1 = 0,1 2

I A(I)

0 17.9A0

1 .062

2 -.000

[ID YOU WANT TO CHANGE ANY VARIABLES AMDNB MDEO, UNCERT, ERT, ESTN, XRTl. XSTNl, lUNCER, IRdoT, ISTATN 7 (YES OR NO)

1' YES

EHIER IHE VARIABLE TO BE CHANGED (HIT RETURN), AND THEN ITS NEW VALUE

T UHCERT T .00 J

ANY MORE VARIABLES TO EE CHANGED ' 7 NO

THE DESIRED 3-TH DEGREE LEAST-S0UARE8 EHUATION HAS A FORM OF Y<X) = SUM OF 4-TERMS OF A(I)»X««I 1 = 0,1,..., 3

I Ad)

0 17.894

1 .076

2 -.001

3 .000

DO YOU WANT TO CHANGE ANY VARIABLES AMONG MDEG, UNEERT. ERT, ESTN, XRTl, XSTNl, tUNOER, IROOT, ISTATN 7 (YES OR NO)

NO

SHIP

is helpful when the least-squares function in question has more than one value of Xr=o or Xsta in the range under consideration), and desired accuracy margins ey^o and isTA- (This option may be repeated as many times as the user wishes.)

• Monitor when the Newton-Raphson iteration process does not converge or does not give the required values of Xy=o or Xsta the desired accuracy so that a new value of

ey^o or esTA may be entered.

Flowchart and Program Listing

A detailed flowchart and the complete program listing are given in figure 3 and listing 1 respectively. The structure of the flowchart is relatively straightforward and should be reviewed along with those definitions or explanations given in the variable-definition text box on page 437.

• Input: the input data is arranged in three groups of DATA statements in the program listing. The first group contains the values for NPAIRS, MDEG, lUNCER, UNCERT, IROOT, XRTl, ERT, ISTATN, XSTNl, and

DEGREE LEAS I- SQUARES EOUATiaM HAS A FORM DF 'I-IERMS OF A(I)«X«*I I • 0,1,..., 3

THE DESIREll 2-X EGREE LEAST

Y(X) = SUM OF :(-TERME OF A

5.090 -7.010

17.960 .062 -.000

440 May 19B1 ® BYTE Publications Inc

^ START ^

Figare 3: Detailed flowchart of the program CURFIT.

COMMON/BLOCK/A, MPLUSl, MPLUS2

NPAIRS.MDEG, lUNCER, UNCERT, IROOT.XRTl, ERT.ISTATN.XSTNl, ESTN.X'S.Y'S

0

MDESRE'MDEG

EROOT"

ERT

ESTATN

-ESTN

MPLUSl

-MDE6RE+1

MPLUS2

°MDEGRE+2

NROOT.

NSTATN=20

I»l

J-1

SUM'O N = l

YES

C(I,J) = SUM J«J+1

J> \ NO MPLUS2

YES

l-l+l

MPLUSl ?

READ MOEG

SUM°SUM+Y(N1*X(N1**(I-"»| | SUM»SUM-<-XCrH**(l'*-J^^

Figure 3 continues on pages 442-445

May 1981 © BYTE PublicaUons Inc 441

ESTN. The second group contains the n values for the independent points X„, or X (NPAIRS). The third group contains the n values for the dependent points Y„, or Y(NPAIRS). These statements are modified to accommodate different data.

• Output: the results consist of the degree of the soughtfor least-squares polynomial and a set of calculated values, which are printed in two columns, representing the I'th subscript and corresponding at in the representation Y(x;=|: a<XX'.

Sample Run

Assuming that the following set of 10 pairs of data is given:

Figure 3 continued:

i

1

2

3

4

5

6

7

8

9

10

x(o

-2.0

-1.5

-1.0

0.0

1.0

2.0

2.5

3.0

4.0

5.0

Y(i)

-25.1

-6.9

3.1

5.0

-6.9

-21.0

-25.0

-25.1

-7.0

45.0

MDEGRE = MOEGRE+1

^MDEGRE < NPAIRS^

! AND I

I^MOEGRESIO J

YOFX. 0.

A(M)>C(M,MPLUS2) M-M+1

C MPLUSl J 1

N.N+I

NO

< NPAIBS

\^ j> >

Tyes

PRINT MDEGRE AND AIM). M.l TO

MPLUSl

[" IROOT.l "I - -I AND

1^ ISTATN-1 J

442 May 1981 © BYTE PublicaUoiu Inc

Figure 3 cptitmued:

NO /^ISTATN

NCODE = 2

CALL NEWRAP(XSTN1,ESTATN, NSTATN,NCODE)

YES

PRINT NSTATN , XSTN 1

YOFX = 0

Y0FX=Y0FX+C(M,MPLUS2)*XSTN1**(M-1)

M = M + 1

NO M> \. 1 ( MPLUSl >

YES

PRINT YOFX

)

READ ICONTl

r XSTNl = 0. ^ I AND

|^ESTATN = 0. J

Figure 3 continued on page 444

• Chemical Engineering: the total heat of combustion (He) of fuel oil is observed to be a monotonically increasing function of °API (degrees on the American Petroleum Institute specific-gravity scale). It is desirable to obtain from the following set of data

YES

Gravity, °API

5.0

10.0

20.0

30.0

40.0

45.0

H„ 1000 BTU/lb

18.24

18.56

19,03

19.42

19.74

19.89

NO

NRERUN^O.

.

Q STOP J a second-degree function representing versus °API

with an uncertainty of less than 0.5% (UNCERT=0.005)

for the given range of degrees API (5 to 45).

As illustrated in listing 3, the required function may be obtained with an uncertainty (to third decimal place) of 0.2% as follows:

We are going to use the program CURFIT to determine the continuous relationship between quantities X and Y as well as all values of Xr=o and Xsta- A quick look at the foregoing tabulation reveals that, in the specified range of Xs (-2.0 to 5.0), there are:

• three distinct values of Xy^o between [X(2),X(3)1, lX('i),X(5)], and lX(9),X(10)j due to the change in signs of corresponding pairs of Y(i)s

• two stationary points of which the maximum one is in the neighborhood of pair number 4 and the minimum

near pair number 8.

Listing 2 illustrates some possible inputs and outputs for this particular example.

Application to Some Engineering Problems

The applications of the program CURFIT to engineering problems are innumerable. Here are a few simple examples of these applications:

H,=17.960-h.062(°API) - negligible term (°API)^ ± 0.2%

To obtain an uncertainty of 0.1%, a third-degree function will be required, as shown in the last portion of the listing.

• Civil Engineering: in an experiment determining the compressive stress-strain diagram of a concrete mix of cement, sand, and gravel (mix proportion by volume is 1, 2, and 4, respectively), the following data is observed (a kip is a 1000-pound load):

unit strain e

(10"^ inch/inch)

0.1

0.2

0.3

0.5

0.6

0.8

1.0

unit stress a

0.44

0.82

1.21

1.78

2.08

2.54

2.83

(kips /inch^)

May 1981 © BYTE Publications Inc 443

Listing 4: Application of the program CURFIT to a dvil Figure 3 conHnued: engineering problem.

00170+7i2>0>.02>0.0..0..0.0.>0.

001V0+.1..2t.3f.5>.6..8.1.

OOZlO-f .44..B3> 1.21 •! •78.2.08.2.S4>2,83

RUN

I RE«0 ICH«NQ [

PROGRAM CURFIT

THE BESIRED 4-TH DEBREE LEftST-SQUARES EOUftTION HAS A FDRH OF r(i() = SUM OF 7-TERMS OF AtI)*5<**I I « 0.1..... 6

I

A(i)

0

.641

1

-8.762

2

95.60B

3

-333.314

4

573.012

S

-477.630

6

153.274

DO YOU WANT TO CHAN8E ANY VARIABLES AMONG MDEG, UNGERTf ERT. ESTNf XRTl. XSTNli lUNCERf IROOT> ISTATN t (YES OR NO) T NO

STOP

Listing 5: Application of the program CURFIT to an electrical engineering problem.

00170t3>l.l..001.0.0..0.rO.O,.0. OOlVO+50..55..60..70..75. 00210'l'237.Zi343.1 > 247. >2S4,9>2SS .8 RUN

PROGRAM CURFIT

THE DESIREIl 1-TH DEBREE LEAST-SBUARES EHUATION HAS A FORM OF Y(X) = SUM OF 2-TERM8 OF AtI)«X**I I =■ Od..... 1

199.937 .785

DO YOU UANT TO CHANGE ANY VARIABLES AMONG MDEG> UNCERTt ERT> ESTNt XRTl. XSTNlf lUMCERi IRDOT, ISTATN T (YES OR NO) ? YES

ENTER THE VARIABLE TO BE CHANBED (HIT RETURN). AND THEN ITS NEW VALUE ? UNCERT ? .0005

ANY MORE VARIABLES TO BE CHANGED T 7 NO

THE DESIRED 1-TH DEGREE LEAST-SOUARES EOUATIOM HAS A FORM OF Y(X) = SUM OF 2-TERMS OF A(1)«X*«I I = 0.1..... 1

199.937 .785

no YOU URNT rn change any UftRIAriLES flMONG MDEG. UNCERT. ERT. ESTN. XKIl. XSfNl. lUNCKR. IRODT. ISTAIN (YKS OR NO) ? Yl j;

ENTER THE VARIABLE TO BE CHANGED (HIT RETURN). AND THEN ITS NEW VALUE 1 UNEERT T .0001

ANY MORE VARIABLES TO BE CHANGED t

r NO

THE DESIRED 3-III LiEURtX LEAST-l^tHlnRFS EnUATrON MrtS EORM OF Y(X) = SUM OF 4-TERMS OF fl(l)«X««I I = O.l .1

207.832 .403 .006 -.000

DO YOU WANT TO CHANGE ANY VARIABLES AMONG MDEB> UNCERT. ERT. ESTN. XRTl. XSTNl. lUNCER. IROOTr ISTATN T (YES OR NO) T NO

STOP

READ UNCERT

READ XSTNl

READ IROOT

READ ISTATN

ICHANG ■ "XSTNlV

ICHANG ^="|STATN'^

p .

NROOT.NSTATN-20

EROOT'ERT ESTATN'ESTN

444 May 1981 © BYTE PublicaHonii Inc

Figure 3 continued:

c

SUBROUTINE NEWRAP (XO,ERROR,N(TER»,NEWTON

D

COMMON/BLOCK/A, MPIUSI, MPLUS2 |

xs(i).xo.,oooi

NPLUS-N + l NMINUS-N-1

yNUM=VDEN=0 I • 1

\ .2 /

Tyes

YNUM =

yNUM + (|-ll*A(l)*XS(N)**(l-2) YDEN =

VbEN + (l-I|*(l-2)*A(l)*XS(N)**(|-3)

YNUMs

YNUM + A(I)*XS(N)**(|-1) YDEN + tl-l)«A(l)*XS(N)**(l-2)

ERR-ABS(YNUM/YDEN)

XO-XS(N) ,YNUM/YDEN | | XS(WPLUS).XS(N1-YNUM/YDEN

XO>XS(NPI.US)

XS(N)'(XS(N)'l-XS(NMINUSI)/2

ERROR'ERR NITEHA-N

c

3

May 1981 © BYTE Publicatlaiu Inc

Deflection (inches)

10.8

21.6

27.0

37.8

48.6

64.8

81.0

86.4

97.2

108.0

Load (pounds)

74.0

117.0

132.0

145.0

150.0

152.0

168.0

183.0

226.0

300.0

Table 1: Data collected when determining the load/deflection characteristics of a bevel spring, supported and loaded at the edges. The program execution in listing 6 will generate the best-fit curve for all points.

For a required absolute uncertainty of ±0.02

kips/inch^, from listing 4 we know that a sixth-degree polynomial representing a versus e is obtained as follows:

a = 0.641-8.762£+95.608£^-333.314e^ +S73.012e« - 477.63e''+153.274e»

•Electrical Engineering: in an electrical testing

laboratory, a technician obtains the following set of data for the determination of resistance R„ at 0°C and temperature coefficient of resistance a of a conductor.

T,

°C

50.0

55.0

60.0

70.0

75.0

Rr,

ohms

239.2

243.1

247.0

254.9

258.8

Listing 6: Application of the program CURFIT to a mechanical engineering problem.

001704'lOr2.1> .03.0.0. >0. .0.0. >0.

00190+10,8,21.6.27..37.8.48.A.64.8.81,.8A.4.97.2,1 OB. 00210+74 , , 117, r 132, . 145, . 150. , 132. . 168. . 183. .226. , 300. RUN

PROGRAM CURFIT

THE DESIREH 3-TH DEGREE LEAST-SQUARES EQUATIDN HAS A FORK OF Y(X> = SUM OF 4-TERHS OF A(I>*X**I I " 0.1 3

1.164 8,261 -.153 .001

no rOU WANT to change any VARIABLES AMONG MDEB. UNCERT» ERT. ESTN. XRTl. XSTNl. lUNCER. IRDOT. ISTATN T (YES OR NO) ? YES

ENTER THE VARIABLE TO BE CHANBEB (HIT RETURN). ANO THEN ITS NEW VALUE T UNCERT ? ,01

ANY MORE VARIABLES TO BE CHANOED 7 ? NO

THE DESIRED 3-TH DEGREE LEAST-SQUARES EOUATION HAS A FORM OF Y(X) = SUM OF 4-TERMS OF AtI)«X««I I ■= O.li.... 3

1.164 8.261 -.153 ,001

[10 YOU UANT TO CHANGE ANY VARIABLES AMONG MDEGr UNCERT. ERT> ESTN. XRri. XSTNl. lUNCER. IROOT. ISTATN ? (YES OR NO)

? 1LS

ENIFR THE VARIABLE TO BE CHANGED (HIT RETURN). AND THEN ITS NEU VALUE

ANY MORE UtlRIABLES TO BE CHANGED ? ? NO

THE DESIRED 8-TH DEGREE LEAST-SBUARES EBUATIDN HAS A FORM OF Y(X) = SUM OF 9-TERi^8 OF A(I)«X**I 1 = 0.1...,. B

178,423 -32,937 3,SS3 -,172 ,O0S -,000 .000 -,000 ,000

nil rnii UANr in uhanr!: any uakiablls among mbcg, uncert» ert. estn.

SRIJ. X:-rNl, lUNCER, IROOT, ISTAtH 1' (YES IIR NU) lHI

■■. ini

Listing 5 gives the following results:

Rt = R,(l + aT) = 199.937 + 0.7857, ±0.05% or Ro = 199.937 ohms a = 0.785/199.937 0.00393 ("C)"'

This value of a indicates that the conductor is made of platinum.

•Mechanical Engineering: the data observed in the determination of the load/deflection characteristics of a bevel spring, supported and loaded at its edges, is illustrated in table 1.

As shown in listing 6, for an uncertainty of 1%, a third-degree polynomial is determined as follows, where D is the deflection:

Load=1.164+8.261(D) -0.153(D)*+0.001(D)*

An eighth-degree polynomial will be required for an uncertainty of 0,5%.■

Glossary

Gauss-jordan elimination: This mathematical algorithm is a means of solving a system of simultaneous equations. It proves to be most effective when the system to be solved has more than three simultaneous linear equations. The procedure itself involves the simplification of a matrix formed from the coefficients of the system of siniultaneous equations. This method is abo referred to as the Gaussian reduction method.

Newton-Raphson method: A mathematical technique which employs an iteration process in which successive approximations are made to determine the roots of a polynomial equation. These successive approximations are calculated from the following formula:

Cramer's Rule: An approach to solving a system of simultaneous equations involving the use of determinants. This method is most desirable when dealing with a small system of equations.

446 May 1981 © BYTE PublicaUons Inc

Event Queue

Circle 91 on inquiry card.

May 1981

May-June

Data-Processing Courses, the Hartford Graduate Center, Hartford CT. For information on these courses, contact the Hartford Graduate Center, Attn: Don Florek, 275 Windsor St, Hartford CT 06120, (203) 549-3600, ext 252.

May-June

Workshops from the National Institute for Management Research, various cities throughout the US. Wordprocessing implementation and supervision and automated office implementation workshops are to be held. The weekend courses are $395 and $495, with discounts available for attendance at two or three workshops. Contact Department C—Wordprocessingfeb2, NIMR Seminars, POB 3727, Santa Monica CA 90403, (213) 450-0500.

May-July

Courses from Integrated

Computer Systems Inc, various cites throughout the US. Courses on computer network design and protocols, multiple micro- and minicomputer systems, and fiber-optics communications systems are to be held. The fees for these 3- to 4-day courses range from $695 to $795. Contact Integrated Computer Systems Inc, 3304 Pico Blvd, POB 5339, Santa

Monica CA 90405, (213) 450-2060.

May-July

Courses from Zilog, various cities throughout the US. An introduction to microprocessors; the Z80, Z8, and Z8000 family of components; PLZ/ SYS programming; development systems; and other topics concerning Zilog products are covered in these courses. Fees range from $150 to $595. For a schedule of times and places, contact Zilog, 10340 Bubb Rd, Cupertino CA 95014, (408) 446-4666, ext 5586.

May 1-2

The Third Annual Computers in Education Conference,

Seattle Pacific University, Seattle WA. This conference will feature panel discussions, workshops, and exhibits. Special emphasis will be placed on the use of microcomputers in elementary and high schools. Contact Jerry Johnson, Seattle Pacific University, Seattle WA 98119.

May i-7

National Computer Conference, McCormick PI, Chicago IL. Approximately 90,000 people are expected to attend this year's National Computer Conference (NCC). The use of robots and artificial intelligence will be among the program sessions at the Personal Computing Festival during the NCC. This will be the first time that personal-computing exhibits

DISCOUNT Computers

from

HAWAII

;applG

II or II Plus

48K $1180.00* 3.3 Disk $525.00* Lang Sys. $399.00* Integer Card $158.00* ^ Apple Soft Card $158.00

IDS Printer

Model 445 $695.00* Model 445G $750.00* Model 460 $1095.00* Model 460G $1145.00^

T I Printer

Model 810 $1625.00'

System B $5299.00' VIP $3599.00* 3005 $7250.00*

*Add 3% for shipping on COD'S pay shipping !n advance. For faster delivery send cashier's checks. Hawaii Residents

Include 4% Sales Tax

In order to gain optimal coverage of your organization's computer conferences, seminars, workshops, courses, etc, notice stiould reach: our office at least three months in advance of the date of the event. Entries should be sent to: Event Queue, BYTE Publications, 70 Main St, Peterborough NH 03458. Each month we publish the current contents of the queue for the month of the cover date and the two following calendar months, Thus a given event may appear as many as three times in this section if it is sent to us far enough in advance.

Computer

Warehouse

P.O. Box 1777 Honolulu, HI 96806 (808) 523-1552

May 1981 © BYTE PublicaUoiu Inc 447

Event Queue,

have joined the rest of the conference in the main exhibit area. Over thirty technical sessions will be held. All major companies will be represented. Contact the American Federation of Information Processing Societies Inc, FOB 9658, 1815 N Lynn St, Arlington VA 22209, (703) 558-3617.

May 5-8

INTELCOM 81/Paris, Paris,

France. INTELCOM (International Telecommunications and Computer Corrference and Exhibition) 81/Paris is part of a program to promote an international dialog on vital subjects in the telecommunications field. This conference attempts to guide the evolution of the computer and its technology by combining the efforts of private companies, government, and equipment users.

For information about attending, presenting a paper, or exhibiting at INTELCOM 81/Paris, contact the Conference Affairs Group, Horizon House, 610 Washington St, Dedham MA 02026, (800) 225-9977; in Massachusetts (617) 326-8220.

May 7-8

The Eighth Annual Computer Show, Valley Plaza Mid

land, Midland MI. This show is being sponsored by the Saginaw Valley Chapter of the Data Processing Management Association. It will feature data processing software and hardware, computer peripherals and equipment, forms, supplies, graphics equipment, and educational services. Contact Don Seidel, DPMA, Saginaw Valley Chapter, University Center MI 48710, (517) 790-4220.

May 11-13

Custom Integrated Circuits Conference, CICC'81, Americana Hotel, Rochester NY. The CICC aims to bring together designers, producers, and users of custom integrated circuits to discuss recent developments and future directions in the field. Papers will be read on applications, algorithm-implementing integrated circuits, fabrication techniques, interfaces and interconnects, computer-aided design, and testing and qualification. Contact Dr Rajinder Khosla, General Chairman, Research Laboratories, B-81, Eastman Kodak Company, Rochester NY 14650, (716) 722-2525.

May 11-13

Fourth Annual Rosen Research Personal-Computer

Forum, Playboy Resort, Lake Geneva WI. This forum features guest speakers from all the major personal-computer hardware and software companies. The Rosen Forum is one of the most prestigious and important seminars in the industry. The registration fee for this 3-day session is $295. For further details, contact Rosen Research Inc, 200 Park Ave, New York NY 10166, (212) 586-3530.

May 11-13

The Thirty-First Electronic Components Conference,

♦ * * WRITE OR CALL FOR FREE CATALOGUE * * *

CALIFORNIA COMPUTER SYSTEMS HIGH IN QUALITY, LOW IN PRICE Z80 CPU, 4 Mhz, with one serial port; 12 slot S-100 mainframe, disk controller, 64K

Dynamic Ram, CP/M 2.2* $1,645.

Interfaced to 2 Shugatt 8', single sided, double density drives mounted in our own,

beautiful MAX BOX with power supply and fan $1,250.

A complete S-lOO system for under $3,000. THE BEST BUY ON THE MARKET.

IMS 5000 and 8000 Systems

Outstanding long term reliability and performance. These systems feature a Z80A CPU, S-100 bus; double density drives (either single or double sided), DMA disk controller, 64K RAM, 2 serial & 1 parallel port. Prices include the very finest implementation of CP/M® available in the entire industry. Hard disk and multi user software options.

Desk top or desk enclosed. 5000 DT with dual, single sided mini drives $3,225.

8000 DT with dual single sided 8' drives S4,7SS.

PER SCI—THF KING AND QUEEN OF DRIVES!

Model 299B: Dual headed drives, total 3.2 MB unformatted $2,300.

Model 277: Dual 8 inch drives, voice roil positioned, IBM compatible, 1600 K BYTES

per drive, unformatted Si,210.

Slimline cabinet and power for either 277 or 299 $ 300.

DRIVES

The MAX BOX: Manufactured by John D. Owens Associates. 8" dual drive cabinet complete with power supply & fan. Will holdQumes,Shugartsor Siemens. Excellent

design and engineering $ 325.

With 2 ShugartaOOR drives $1,250. With 2 QUME Double sided drives $1,650.

HAZELTINE 1500 $925.

1510 $1,030

AMPEX DIALOGUE 80 CRT . S950.

Removable keyboard, 2 page memory, (4 optional), block transmit.

CENTRONICS 737 $780.

Same as TRS-80 Model IV

Apple serial/parallel interface ... $195.

EPSON MX80B $550.

IMS MEMORY 16 K static $350.

32 K static $650.

64 K Dynamic with parity $755.

TEI MAINFRAMES, S—100

12 slot, table top $500.

22 slot, table top $670.

Rack mounts, add S 50.

50 Hz, 220 volts, add $ 50.

TELEVIDEO CRTs

912.,$780. 920..$850. 950. Si,050.

WE EXPORT:

Overseas Callers:

TWX 710 588 2844

r

Phone 212 448-6298 or Cable: OWENSASSOC

SEE OUR AD FOR NFVV PRODUCTS ON PAGE 18

JOHN D. OWENS

Associates, Inc.

12 Schubert Street Staten Island, New York 10305

212 448-6283 212 448-2913 212 448-6298

448 May 1981 © BYTE PubUcaUona Inc

Event Queue

Colony Square Hotel, Atlanta GA. Papers will be read on semiconductor-processing technology, optoelectronic devices, manufacturing technology, materials, hybrid microcircuits, discrete components, interconnections, reliability, and connectors. Contact T G Grau, Bell Laboratories, Whippany Rd, Rm 3B-312, Whippany NJ 07981; or Electronic Industries Association, 2001 Eye St NW, Washington DC 20006.

May 14-16

The Tenth ASIS Mid-Year Meeting, Fort Lewis College, Durango CO. The American

Society for Information Science's (ASIS's) theme for this year's meeting is "Using Information." Among the topics to be addressed are user studies, decision making, organizational change, govenunent, education, management, access to information, and designing information systems for use. For information, contact ASIS, 1010 16th St NW, Washington DC 20036, (202) 659-3644.

May 16

Introduction to Pascal,

Princeton NJ. The Princeton, New Jersey, chapter of the ACM (Association for Computing Machinery) is sponsoring this seminar. Contact Ronald Orcutt, EDUCOM, POB 364, Princeton NJ 08540; or Bill Hafstad, (201) 457-4055.

May 17-20

Expo '81, Loew's Anatole Hotel, Dallas TX. Expo '81 is a combination of exhibits and technical sessions. The exhibits cover everything from graphics systems to industrial computer-control systems. The technical sessions range from tool design, design engineering, and robotics to numerical control. For more information, contact Num

erical Control Society, 519 Zenith Or, Glenview IL 60025, (312) 297-5010.

Moy 20-22

Joint Conference on Easier and More Productive Use of Computing Systems, University of Michigan, Aim Arbor

MI. This conference intends to combine the insights of the social sciences, humanities, computer science, and human-factors engineering.

Contact Gregory A Marks, 4258 Institute for Social Research, University of Michigan, Ann Arbor MI 48106, (313) 763-3482.

May 20-22

Videotex '81, Royal York Hotel, Toronto, Ontario,

Canada. Videotext information systems allow users to call up information, make reservations, pay bills, exchange electronic mail, read

an electronic newspaper, shop, and play video games. This conference will review videotext developments in Europe, Japan, and North and South America. Demonstrations of videotext systems will be given. Seminars on standards, legal aspects, and economic issues will be featured. Contact Videotex '81, 316 Lonsdale Rd, Suite 3, Toronto, Ontario, M4V 1X4, Canada, (416) 598-1981.

* * * TELETYPE MODEL 43 INVENTORY SALE

* * *

i TELETYPE

i Model 4320 AAA $ 885.

\ 220V. model with transformer installed

? inside cabinet $ 985.

\ Model 43ASR, 8 level, 1" tape . $2,595. [ Limited supply of Model 45 available.

GRAPHICS SOFTWARE [

On line, real time, for the M9900 to | drive the Microangelo. For use in design of PC board masks, IC masks and other i! applications $1,000. |

CORVUS HARD DRIVES j

We are the S-100 CORVUS dealer in the i New York area.

MODEL 11, Hard Disk System $4,820. | Mirror Backup System S 715.

j TELEBUFFER 43 ASR , . $945. j Circuit card designed for internal instal9 lation in the Model 43 Teletype. 1 Changes the 43 into a buffered send/ i receive device, enabling it to function as £ a Telex without paper tape. Provides \ from 4K to 16K bytes of internal memp ory for storage of message. Contents of i memory may be edited and manipulated ! In preparation for transmission. Options i include forms control and answer back.

TARBELL !

Double density controller $420. *

Cables $ 40. \

Complete TARBELL Product Line | Available. i

UPGRADE DEC LA 35/36 $750. j

Increases baud rate to 1200. Micropro- i cessor controlled. Many options avail- ■ able. Enthusiastic user response. Long- ! term reliability. From DataSouth. i

' IRM ^101 CRTMndplID tl IPS

\ Model 20 $1,395.

■ Selectric-like, detached keyboard. 9x16 H dot matrix. Maintenance contract from B IBM only $70 per year

Communications Software from ; from Hawkeye Grafix j

Enables communications from a micro i

to a terminal or to another micro, mini ! or maxi computer. I Object Code $75. Source Code $250. \

i ITHACA INTERSYSTEMS

1 Full S-100 IEEE Compatibility! Full 24 H address bits. DMA disk controller. SYS! TEM 2A includes 20 slot mainframe

y with front panel, 64K Dynamic RAM. i Z80 CPU, 4 MHZ, extended addressing \ capability. 4 parallel, 2 serial I/O floppy ; controller. Our discounted price, $3,415.

3M SCOTCH" Diskettes bqxes \

IBOX Price ! often per box i

Model 740,8" single sided, |

single density . . $29.00 $26.50 [ Model 741,8" single sided, jj

double density. 38.00 35.00 i Model 743,8' double sided !

double density. 46.50 42.50 | Model 744,5 '-"j" soft sectored single sided, !

single density.. 29.00 26.50 \

\ MARINCHIP SYSTEMS M9900

: Elegant 16 bit CPU, S-100 compatible, 1 multi user, multi processor operating 1 system. BASIC, FORTH, META, PASH CAL, Word processor, text editor. 1 CPU kit and software package . $ 550.

\ Assembled $ 700.

« Complete system, 64KB,

S two drives $4,995.

CAT from NOVATION \

Originate/Answer back $175. ;

CAT-D $185. 5

Connects directly to telephone line with : a plug-in jack. Eliminates need for 1 acoustic coupler. i AUTO-CAT $240. 1

1 MICROANGELO $2,280.

i High resokition graphics system. 15", 1 22MHZ, green phospher screen, 72 key ' keyboard; includes complete cabling i and software. From SCION, i S-100 Graphics card $ 960.

^ WE OFFER A FULL RANGE OF EXPERT CONSULTING SERVICES s

JOHN D. OWENS

Associates, Inc. SEE OUR AD ON FACING PAGE

May 1981 © BYTE Publicadons Inc

449

Event Queue

May 21-23

Annual Conference of the Educational Computing Organization of Ontario,

Sheraton Centre and the Ontario Institute for Studies in Education, Toronto, Ontario, Canada. Exhibits on the use of computers in schools and discussions on how to locate suitable educational materials will be featured. Contact the Conference Office, OISE, 252 Bloor St W, Toronto, On

tario, M5S 1V6, Canada.

May 22-24

National TRS-80 Microcomputer Show, Statler Exposition Center, New York NY. Exhibits from over 100 manufacturers, distributors, and retailers of equipment for the TRS-80 Models I, II, and III, and Color and Pocket computers, will be featured. Seminars and talks will be held at the show. Contact Kengore Corporation, 3001

Rt 27, Franklin Park NJ 08823, (201) 297-6918. May 26-29

Office Korea 81, Korea Exhibition Center, Seoul, South Korea. Exhibitors will come from the United States, Japan, the United Kingdom, and South Korea. Computers, copiers, facsimile systems, and office equipment and supplies will be presented. Further information may be obtained from Clapp & Poliak International, 7315

Wisconsin Ave, Washington DC 20014, (301) 657-3090.

May 30

Amateur Fair, Minnesota

State Fairgrounds, St Paul MN. Exhibits, prizes, and booths are featured at this swapfest for computer hobbyists. Contact the Amateur Fair, POB 30054, St PaulMN 55175.

June 1981

]une 6-9

Atlanta Small Computer Show, Atlanta Hilton, Atlanta GA. Producers of small computers, peripherals, supplies, and services will be exhibiting at this show. Business owners, corporate and government executives, dataprocessing managers, doctors, lawyers, and other professionals are expected to attend. Obtain additional information from The Atlanta Small Computer Show, 4060 Janice Dr, Suite C-1, East Point GA 30344, (404) 767-9798.

June 9-11

Understanding and Using Computer Graphics, Chicago IL. This seminar covers the

latest in graphic-system technology, including hardware, software, and apphcations. Contact Bob Sanzo, Frost & Sullivan Inc, 106 Fulton St, New York NY 10038, (212) 233-1080.

lune 14-18

The Second National Conference of the National Computer Graphics Association,

Baltimore Convention Center, Baltimore MD. Computer-graphics demonstrations, exhibits, and workshops will be held. Contact the National Computer Graphics Association Inc, 2033 M Street NW, Suite 330, Washington DC 20036, (202) 466-5895.

June 16-18

NEPCON East '81, New York Coliseum, New York NY. This exposition is aimed at

bitroducin^

J«LJrO-CiT

It ^ets you dGftfaehoc

Auto-Cat^*^ lets your computer terminal answer other terminals over the phone line automatically.

It's the deluxe way, for example, to receive a program from a friendly computer. Or take data from any of the information sources. Then store the information in your computer's memory— and have it there at your beck and call—all automatically.

Auto-Cat is a state-of-the-art originate/auto answer, all digital, crystal controlled unit with everything in one compact package. It sits right under your phone.

It's FCC approved for direct telephone line connection. You just take it home and plug it in.

Cost? Less than any other comparable modem. Under $250.

And it's from Novation. The recognized leader in personal communications.

Auto-Cat

Novation

Call for details:

(800) 423-5410

In CaUfornia (213) 996-5060

Available at Avnet Electronics, Hamilton Electro, Hamilton Aynet, Kieiulff Electronics, Byte Shops, Computerland, and your local computer store.

Novation, Inc., 18664 Oxnard Street, Tarzana, California 91356

450 May 1981 © BYTE Publications Inc

Circle 286 on Inquiry card.

Event Queue

engineers, prototype developers, production specialists, and testing personnel. Technical programs will be presented. Contact Industrial & Scientific Conference Management Inc, 222 W Adams St, Chicago IL 60606, (312) 263-4866.

}une 17-19

National Educational Computing Conference, North Texas State University, Denton TX. This conference will provide a forum for individuals and institutions interested in educational computing. Computer literacy, computer education for teachers, and computers in education are some of the topics to be covered. Contact Dr Jim Poirot, NECC-81 General Chairman, Computer Sciences Department, North Texas State University, Denton TX 76203.

May 29-31

The Sixth Annual Computerfest. Franklin University, Columbus OH. Talks on robots and calculators will be featured. Microcomputers and small-business systems will be presented. This show is being sponsored by the Midwest Affiliation of Computer Clubs and FrarJclin University. Contact Computerfest '81, Paul Pittenger, 215 Delhi Ave, Apt J, Columbus OH 43202, (614) 224-6237.

June 23-25

Comdex/Spring, Madison Square Garden and the New

York Statler Hotel, New York NY. Computer and computer-related manufacturers, systems houses, computer retailers, dealers, distributors, manufacturers' representatives, commercial OEMs (original equipment manufacturers), and other related businesses will be exhibiting. Contact The Interface Group, 160 Speen St, Framingham MA 01701, (800) 225-4620; in Massachusetts, (617) 879-4502.

lune 29-luly 1

The Nineteenth Annual

Meeting of the Association for Computational Linguistics, Stanford University, Stanford CA. Syntax, parsing, emd sentence generation, computational semantics, discourse analysis and speech acts, speech aiwlysis and synthesis, machine and machineaided translation, and mathematical foundations of computational linguistics are some of the topics that will be

discussed. Contact Don Walker, Artificial Intelligence Center, SRI International, Menlo Park CA 94025, (415) 326-6200, ext 3071.

July 1981

]u\y 29-31

The 1981 Microcomputer Show, Wembley Conference Centre, London, England. Seminars on microcomputer

applications in business, production, and education will be presented. Topics for conference sessions include hardware avaOability, software packages and development, automatic test equipment, robotics, and process control. Exhibits from major European and American manufacturers will be featured. Contact TMAC, 680 Beach St, Suite 428, San Francisco CA 94109, (800) 227-3477; in California, (415) 474-3000.B

Cat.

woifft be aphone without one.

Fast, accurate, reliableCat. Someday there won't be a computer without one.

-and under $199.

1^

by

The only way to realize the full potential of your small business or.personal computer is to tie it in with other computers. And the best way to do that is wiUi a Cat acoustic modem.

A Cat modem lets your computer talk face to face with any other compatible computer or terminal within reach of your phone, over standard telephone lines.

You can work at home using the computer at your office. Send or receive data from anywhere. Or swap programs.

Available at Hamilton/Avnet. Kierulff Electronics, Byte Shops and your local computer store. Novation, Inc., 18664 Oxnard Street, Tarzana, California 91356

ovation

Tie your computer into the world. Call for details

(800) 423-5410

In California (213) 996-5060 Computerland,

Circle 287 on inquiry card.

May 1981 © BYTE Publications Inc 451

Circle 31 on inquiry card

U.S.A.

ARISTO/POLKS

314 5th Avp. (32 ST) N.Y.C.. N.Y. 10001 Telephone: (212) 279-9034

EPSON

MX70 $399

MX80T $499

The worlds first printer with disposable

print heads. Built in dependability with an extensive range of features

OKI DATA

83 $ 949

Tractor Unit $75

The small, quiet, light, highly dependable printer with three way paper handling. Single sheet/roll/pin feed.

MjJliJ:NIJIt>L^

$ 775 + cable

*7x9 dot matrix *3 way paper handling *5, 10 or 16 chrs. per inch *80 chrs. per seconds proportional/50 chrs monospaced

TEC RO STARWRITER

f

$1495

Typewriter quality Daisy Wheel Printer Parallel or Centronics Interface *Diablo Wheels and Ribbons compatible

TYMAC APPLE TO CENTRONICS INTERFACE CARD Including CABLE $119.99

O.S.I. SUPERBOARD III

$ 279

All European trade enquiries to:

NORTHAMBER LTD

Great Oak House, Esher.Surrey,England KT10 9BR Telephone: 03^2 62071

Technical Forum

Build a Noise-Based

Random Number Generator

Terry Mayhugh, 11632 Midhurst Dr, Concord TN 37922

At some time, nearly every programmer finds it necessary to generate random numbers. If a card dealer is

being simulated, or a Klingon scanner display is being created, the RND function available in most versions of BASIC may be adequate. However, the pseudorandom sequence generated by RND can bomb in critical applications where a truly random number sequence is needed. Truly random numbers are extremely difficult to generate, especially within a nonrandom machine such as a computer.

The best that can be accomplished purely by software is the generation of finite-length sequences that appear to be random. However, the actual members may be related to specific calculations recently completed by the computer. Such complications will contaminate the results of signal-recovery simulations or digital-filter problems. Even a computer card game may be biased by a previous bet. Ideally, the actual random number generation should be done outside the computer.

Figure 1 is a block diagram of a simple generator capable of producing truly random sequences of any length. A free-rurming oscillator, miming asynchronous

OSCILLATOR

8-BIT COUNTER

0

PARALLEL INPUT TO COMPUTER

COMPARATOR

NOISE SOURCE

Figure 1: Block diagram of a generator that produces true random numbers. Through pulses created by the random-noise source, the free-running oscillator is gated to the 8-bit binary counter. Since the instantaneous amplitude of the voltage from the noise source is unpredictable, the width and arrival of the gate pulse generated by the comparator are also random. Therefore, the 8 hits available from the counter are truly random.

MAGIC WAND™ $325

This powerful word processor is in stock for most CP/M cornpatible systems, Including Redo Sfiack. North Star, vector Graphics, Crcmemco and APPLE [with 2-80 card @ S295 and VkJex 80 column board @ $295]. Wa will custom configure your diskette if you will specify: CPU, terminal, printer.

Our fully interactive

MAIL MAGIC^'^

mail management software, with 14 user defined fieUs ami full merge and sort capability is avBilebleforS149,

We will also quote on all specific hardware and software for APPLE, PET and Vector Graphics.

Computer City

P.O. Box 60284 B Houston TX 77205 (713)821-2702

Magic Wand is a registered trademark of

Small Business Applications Mail Magic is a registered trademark of Computer City

Circle 78 on Inquiry card.

.

NEWS

Interface converts Your Typewriter Into printer

• Finest print qualitv -low cost

• Easy instailation • Quick delivery

■ Fits iBM SEiiCTRiC* typewriter with no modification.

• For TRS-80*, Apple*, or any parallel or |!S232 port.

• write orphoneformore Information, todayl

— U.S. and worldwide sales—

iPEX

INTERNATIONAL INC. 16140 valerlo St.

van Nuys.CA 91406 USA TEL: 213/781-0020 TU/TWX: 910-495-1767

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Used micro computer systems 100% functional, $600 to $1500. Video terminals & keyboards, $50 to $700. Stringy floppy units-brand new, $300. All the above with documentation. Computer cabinets, 19" rack, $50 to $100. Power supplies, capacitors, ribbon cable, cooling fans, misc. components & hardware. We buy used microcomputer systems —all types. Also deal in IBM, Univac, Data General and Data Point.

CALL VIC CLOUGH at

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DATA HARDWARE

701 Beta Dr. #4 Cleveland Ohio 44143

DEALERS WELCOME

Circle llZ Un Inquiry card.

Fine Software Tools in C

The Toolbox

list prints th<it missing source listing; xref cross rt.'lt'rtMu (.' C programs sort alphabetize by all or part of text line, col arrange text In columns on page, print paginates text for hard copy, and more

All programs are in portable Whitesmith C itref and list are compalible with the compiler s error listiny Title lines on list and print output includes the date on RT-11 systems Source code on 8" floppy and manual available immediateiy for (45 (tax and shipping included). Specify RT-11 or CP/M format.

The Toolsmith

Dept. BYTE P. O. Box 22511 San Francisco, CA 94122

RT-ll IS a trademark of Digital Equipment Corp, CP/M is a trademark of Digital Research,

Scotch'

DISKETTES

SAVE 40% cr^rr

5y4"Sgl. Dens. 26.70/10

Specify soft, 10 or 16 hard sectors

8"Sgl. Dens. 27.30/10 8"Dbl.Dens. 35.80/10

Specify soft or 32 hole hard

Add $2.00 shipping - Michigan add 4% tax

LYBEN COMPUTER SYSTEMS 27204 Harper Ave. St. Clair Shores, Ml 48081

Authorized Distributor Information Processing Products

Circle 224 on Inquiry card.

wabasK

When it comes to Flexible Disks, nobody does it better than Wabash.

MasterCard, Visa Accepted. Call Free: (800) 235-4137

PACinc

EXCHANGES

100 Foothill Blud San Luis Obispo. CA 93401 (In Cal call (805) 543-1037)

Circle 205 on Inquiry card.

Circle 413 on Inquiry card.

Circle 312 on inquiry card.

ATARI .OWNERS

SCREEN PRINT INTERFACE

Obtoin lurdcopy of qhy screen Imoge (graphics and / or text) on sutler o TRENDCOM 200 or IDS 440 Poper Tiger printer. Simply attach ttie supplied parallel printer cable ond load the software Irom cassette (may be transferred to Disk). Obtain a "picture" of the screen on your printer under direct (CTRL?) or program (XIO) cotttrol. Works In oil graphics / text modes OS well os LPRINT ond LIST "P:" ^ .e r»

Only $ 1 39 Parallel Printer Interface for the ATARI 400 / 800

Connects to conltoller jocKs 3&4 works wirti BASIC / DOS / ASSEfriBLER Tftree printer connectors available:

ATARI 400 / 800 TRENDCOM 100 / 200 A4P-t A8P-1 CENTRONICS 730 / 737 A4P-2 A8P-2 CENTRONICS 36 PIN* A4P-3 A8P-3

CA soles odd 6% tax $XO 95

MC / VISA accepted. O 7 •

* Fits oil ottier porollel Centtonics plus Anodex. Bose 2.

Epson. Compnnr and Microtek Order by port number, ATARI IS 0 recognizea rraaemark ol ATARI, Inc

/iMCROTRONICS, inc. »

1125 N, Golden Slate Blvd, / Suite G

Turiock, CA 95380 (A) (209) 667-2888 / 634-8888

CONVERT ANY TV

TO A HIGH QUALITY MONITOR

- NEII

HICH OUALITT

, TTTTTTT » V

1

t T K y =

T » V 1

T V 1

1 MOD -- KITS

• Hot Chassis or Transformer sets

• 64-80 characters per line

• By-passes tuner & I.F.

• Normal viewing unaffected

• Safe—Easy kit installation

ACVIVI Hi-resolution $34.95 ppd.

V.A.M.P. INC. Box 29315, Los Angeles, CA 90029 Calif. Residents add 6% Sales Tax

Skyl.' EleclrH

Skyles Electric Works

231 E South Whisman Road Mountain View, CA 94041

Circle 225 on Inquiry card.

Circle 422 on inquiry card.

Circle 368 on inquiry card.

Technical Forum,

to the microprocessor clock in the computer is gated to an 8-bit binary counter through pulses created by a randomnoise source. Since the instantaneous amplitude of the voltage from the noise source is not predictable, the width and the time of arrival of the gate pulse generated by the comparator are unpredictable. The sequence of numbers available from the counter is truly random (if you do not try to sample them at an excessively high rate). For the component values shown in figure 2, there should be no problem in any microprocessor application.

The numbers generated by this technique are uniformly distributed; any number in the set of all possible numbers (0 thru 255) has the same probability of occur

ring. The mean or expected value of the distribution lies at the center of the set of all possible numbers.

Circuit Description

The noise of zener diode Dl is amplified by IC4 and IC5, which are configured as high-gain wideband amplifiers. The amplified noise from ICS is compared with the DC v^iper voltage of R18 at the input of comparator IC6. A logic level is generated at the comparator output and is used to gate on and off a TTL (transistortransistor logic) oscillator (IC2), which runs free at about 3 MHz. A cascaded dual 4-bit binary counter (IC3) is clocked by this oscillator.

+ 12 TO +16V

, 8-BIT C> ) INPUT TO 'COMPUTER

Figure 2: Schematic diagram of the random number generator described in this article. The noise of Dl is amplified by IC4 and ICS. The amplified noise from ICS is compared with the DC wiper voltage of R18 at the comparator input of IC6. The level generated at the comparator input gates IC2 (running at about 3 MHz). The oscillator is clocked by ICS (a cascaded 4-bit binary counter). The circuit should be shielded. Pin numbers shown for ICl (Silicon General 3501) are those for a TO-5 package.

454 May 1981 © BYTE Publications Inc

!! ftCAL TIMG

The TIME MACHINE from AUPHA OMEQA COMPUTER SYSTEMS isnt iMt anothardlfiitalc|6tdtchtp sumxjnctod by interfBCe circuitry. It's an intelligent microcomputer

based periohcral 'Jcvicp.

The TIME MACHINE communii: itija with your compitlor via a serial I/O portataumrMleCtabledBta rate between

300 and 2iQQ baud. RS-23a, RS-422, or current loop

communication rn.iy ho u;;r.d.

Battery protection agoinsl power loss is included. The TIME MACHINE automalically computes day of the week and leap year. Buffered output pulses at one second, one minute, and orm hour Intervals are provided.

Oimef«ians are 2.S x 4.''S x 7.5 inches. Batteries, power supply, ml communtcaMw cable are included.

price Is only $450 single lot end qu»^lty dscdunts are .mailable. Dealer inquiries invited. Off the shelf del I very.

ALPHA

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P.O,Bai T2J f CtHiMt. Ortgon ST330

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3Nappa Lane. Westporl, CT 06880

APPLE DISKS

Each Containing Multiple Programs

BASIC TUTOR SERIES — V 101-107

A series of seven disks with 67 studies designed tor novice programmers. Teaches how to program your APPLE, in APPLE soft basic. $10/Doc and DemoDisk, or $190/Series and Doc.

Tutor I — Intro lo programming commands $32

Tutor II — Graphic commands - Hi-fes & Lo-res ... 32 Tutor III — Studies in text tiles and word processing 32

Tutor IV — How to create muilc programs 32

Tutor V — Novice program sample studies 32

Tutor VI — Programming techniques 32

Tutor VII—Ulimiet for study and use 32

Q/A Series V 120-140

Subject matter studies. Each disk has 6* pgms within the subject. All use Question/Answer format. Great for discussions. $10/Doc and Demo, or $32/Disk and Doc. 0/A — American History: Pfesidents Wars, etc Q/A — Human Biology: Bones, Organs, Diet, etc Q/A — Inorganic Chemistry; Elements, Ions, elc. Q/A — Elemantaiy Astronomy: Stars, Consiellalions, etc. 0/A — World HMory: European, Ancient, Asian, etc. 0/A — General Biology: Plants, Animaia, etc Basic Aid — V 108

Useful routines and utilities to aid the novice programmer, increases speed and efficiency when you Iranspfani these routines into your programs SlO/Doc - $39/Disk and Doc. Astronomy I ■ S32 Physics - $32 TssHorm - $39 Potpourri ■ S24 Ed Damo - S24 Populations - $24 - Others in Catalog inventory - S50 Accoun1s-S£0 ■ $10/Doc. each. All orders pre-paic or P 0 S Send lor free catalog. Add $2.00/mail each order - Guaranteed disk runs.

9 TRACK TAPE DRIVES

34 MEGABYTES 800 BPI 45 IPS BRAND NEW

S4850 VALUE

$2400

NEW IN ORIGINAL

BOXES

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> BARGAIN PRICED MINI-COMPUTER UPQRADE. OEM List S4B50-^

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Technical Forum <

Parts List

IC1 Silicon General SG3501 dual regulator

IC2 74LS124 oscillator

ICS 74LS393 dual 4-bit counter

IC4, ICS Harris HA2517 op-amp

IC6 LM311 comparator

Ri, R2 4.7 ohm 1/4 W 5% CO (carbon composition)

R4, R5 680 ohm 1/4 W 5% CC

R8,R10,R14,R15,R20,R21 51 oiim 1/4 W 5% CC

R17 lOk-oiim 1/4 W 5% CC

R19 100 ohm 1/4 W 5% CC

R22 47 k-ohm 1/4 W 5% CC

R23 1 k-ohm 1/4 W 5% CC

R16 1.5 k-ohm 1/4 W 5% CC

R3 9.00 k-ohm 1/8 W 1% mF

R6, R11 1.00 k-ohm 1/8 W 1% mF

R7,R9,R12,R13 147 k-ohm 1/8 W mF

R18 10 k-ohm miniature 10-turn potentiometer

C1,C2,C4,C6,C10,C14,C15,C19,C20 1 /iF 25 V tantalum C9,C12,013,C17,C18,C21 ,C22,C23 6.8 jiF 25 V tantalum C3,C5,C8,C11,016 0.01 ii.F disc ceramic C7 180 pF disc ceramic D1, D2 IN747 zener diode

Table 1: Parts list for the circuit shown in figure 2.

A great deal of power-supply decoupling and isolation is used in the analog section of the generator. This is necessary to avoid picking up the 60 Hz power signal or any other periodic power-supply noise that could destroy the randomness of this circuit.

The circuit should be constructed within a shielded enclosure to avoid RF (radio frequency) or other interference that could cause a periodic output from IC6. The ±12 V supply in my SwTPC 6800/2 (actually ±14 V) has an unacceptable amount of 60 Hz ripple for this application, so a dual IC regulator (ICl) regulates this voltage to a clean ±10 V for the analog electronics.

Alignment of the generator is relatively simple if an oscilloscope is available. R18 is adjusted while viewing the waveform at pin 7 of IC2. This potentiometer should be adjusted until the waveform at pin 7 spends an equal amount of time in its high and low status. That is, the brightness of the scope trace should be adjusted for uniform brightness at its top and bottom edges. If no scope is available, set the potentiometer for 50 to 100 mV at the wiper.

The eight counter bits may be connected in any order to the eight lines of the parallel port of the computer. In my particular application the port is read with a loadaccumulator instruction when a number is needed. No strobe or handshaking is used.

A Gaussian, or normal, distribution can also be created using this uniform generator. Using what statisticians call the Central Limit Theorem, a normal distribution can be created by averaging several random numbers of any other type distribution. I have found that a convenient and sufficient number of samples in most cases is 64. Averaging multiples of 2 maintains maximum speed because the division in the averaging process can be done with simple accumulator shifts. Of course, speed is sacrificed with this method because only one normally distributed number is created for every 64 uniform numbers generated. ■

456 May 1981 © BYTE Publications Inc

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|J 1981 / DISCOUNT

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TRS - 80*

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Interface your level II computer to your temperature sensors, wind sensors, joysticks, etc. Control your heating/cooling systems, solar collectors, wind generators, etc. The uses for this interface are limited only by your imagination.

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RS-232 PROBLEMS?

LET THE RS-232 TESTER HELP YOU SOLVE YOUR COMPUTER INTERFACE PROBLEMS. DESIGNED TO CONNECT IN SERIES WITH ANY RS-232 INTERFACE, IT DISPLAYS THE STATUS OF SEVEN OF THE MOST IMPORTANT LINES: TRANSMIT DATA, RECEIVE DATA, REQUEST TO SEND, CLEAR TO SEND, DATA SET READY, CARRIER DETECT, AND DATA TERMINAL READY. THE RS-232 TESTER REQUIRES NO POWER AND MAY BE LEFT IN THE LINE PERMANENTLY.

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IJCAI-81

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24-28 AUGUST 1981

UNIVERSITY OF BRITISH COLUMBIA

VANCOUVER. B.C.. CANADA

The major international artificial Intelligence conference All-day Tutorial Program, August 24 Week-long A.I. Research & Development Exhibit Program

Conference Information:

l<ic)i,.i>l K,.s,->ntH-i;j. Dl'pI ol ("onipul,.'! SciL'iict; Univvisiiv uf Briii^ti Columbia, Vatu .niVLT. B C , Canada VbT 1W5

Tutorial and R&D Exhibit Prosrams Information:

Louis G. Robinson.

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Stanford. CA 94305. U.S.A. (415)495.8825

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Technical Forum

Fast Fourier Comes Back

Alastair Roxburgh, 50 Maitland St, Dunedin, New Zealand

The program "Fast Fourier for the M6800," by Richard H Lord (February 1979 BYTE, page 108), contains an overflow bug that I discovered while testing a version of the program written for the 8080 processor. (See listing 1.) After the exact nature of the fault was ascertained, a theoretical explanation for it was easy to find. The problem concerns the maximum two's-complement value allowed before scaling commences. The 6800 program requires that any data point outside the range of —64 < data < 64 be scaled down before the next pass. Scaling divides all data values by 2. However, during passes 2 thru 8 it is quite possible for the results of arithmetic operations to exceed the 8-bit two's-complement-number range of —128 < data < 127. The reason for this can be seen by referring to lines 205 and 215 in the original program. These lines yield:

RM' = RM + RN*COS(X) + IN*SIN(X)

Letting RM=RN=IN=M, the maximum data value,

then:

RM' = M*(l -1- COS(X) + SIN(X)).

The maximum value of RM' is then M times the maximum value of 1 -I- COS(X) -I- SIN(X). This maximum value occurs at an angle of 45°, given by TAN(X) = 1.

Thus, the maximum value of RM' is M(l + y/l ) or approximately (2.414)M. Letting RM' = 127 (the maximum positive 8-bit two's-complement-data value), then M = INT(127/(1 -h V2 )) = 52.

Thus, the data should be scaled before each pass if any point exceeds the range —52 < data < 52. It makes little difference to the spectra whether the relational operators here are greater-than-or-equal or merely just greaterthan. The 6800 program should be amended accordingly:

00268 CMP A # $CC (-52) 00270 CMP A # $34 (52)

The test program that uncovered the overflow error used program-generated square waves with a period of

six data points (equivalent to 10.667 Hz using a sampling rate of 64 Hz). Every amplitude from 128 ± 127 down to 128 ± 1 was tested and the power spectra, as well as SCLFCT, were printed out (reqviiring approximately three hours at 110 bits per second).

Each transform in the 8080 program takes 3.6 seconds to compute with a 2 MHz processor clock. The power calculation is fast, because a lookup table is used.

When FFTs (fast Fourier transforms) are computed on a minicomputer that has sophisticated error-trapping hardware, the usual practice is not to perform any prescaling, but instead to allow arithmetic overflow to occur, do a software interrupt to a scaling routine, and return. This way, fewer scalings of all the data are required, yielding results with the maximum possible numerical precision. The 6800 can detect two's-complement overflows and can efficiently perform (two's complement) arithmetic shifts to scale the data, but it does not have an automatic overflow trap. The advantage of slightly better numerical results would be outweighed by the time required to call an overflow-checking subroutine after most arithmetic operations. The 8080 is even worse off; it has neither a two's-complement-overflow indicator nor a single-instruction equivalent of the 6800's ASR.

Text contintted on page 460

A Message to our Subscribers

From time to time we mal<e the BYTE subscriber list available to other companies who wish to send our subscribers promotional material about their products. We take great care to screen these companies, choosing only those who are reputable, and whose products, services, or information we feel would be of interest to you. Direct mail is an efficient medium for presenting the latest personal computer goods and services to our subscribers.

IWany BYTE subscribers appreciate this controlled

use of our mailing list, and look forward to finding

information of interest to them in the mail. Used are our subscribers' names and addresses only (no other information we may have is ever given).

While we believe the distribution of this information is of benefit to our subscribers, we firmly respect the wishes of any subscriber who does not want to receive such promotional literature. Should you wish to restrict the use of your name, simply send your request to BYTE Publications Inc, Attn: Circulation Department, 70 Main St, Peterborough l\IH 03458. Thank you.

458 May 1981 © BYTE PubUcatioiu Inc

Listing 1: The 8080 version of the fast Fourier transform program originally written for the 6800 processor by Richard Lord. In this version, Mr Roxburgh has corrected an overflow problem that he discovered and diagnosed in the original version.

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0R50

PRVl: RAR

;MnUF L5 PIT DP ni.PT 1

8 ft;i.i

4F

0860

: INTH CY S. SHIFT

R 034

7P

OR? 0

wnu A, F

R 035

1 7

0R8 0

FAL

; IW RFVFRSF HRDER PACK

R 036

SF

0890

Knu Ej A

; INTO RLPTP.

0900

MOV AjC

8 038

OS

0910

DCR P

8 039

CP

38

RO

O9P0

JNZ PRU1

D930

KDV A*L

8 03D

PP

094 0

CKP E

;CO;PARE VALS» t IF

16

JC SUPI

I SAME* DON*T SWAP.

/'v

sv'ap: wnu c*M

;GET VAL I INTO C.

n

LPAX D

IGFT VAL P INTO A.

R n/T

-Iv

noR n

MOV M» A

ISTORF IN SWAPPED ORDER.

R fli/

nqqo

t^ny a* c

8 O^lS

IP

1000

ST AX D

8 046

PC

10 10

SUP I I I NR 1.

R 047

CP

PF

RO

lOPD

JNZ PITRFU

R04A

1030

j;

8 04P

1040

;JFFT FIRST PASS.

8a4A

1050

8 048

CO

an

Rl

1060

PASS I(CALL SCALE

JSCALF IF DATA DVFR-RANGF.

8 04D

PI

00

«5

107 0

LXI K«RKAL

8 050

7F

I 08 0

PAIt MOV A«M

IGPT RM.

R0S1

4F

1 090

MPy r*A

ISAVF RM.

R 05P

PC

1 100

INR L

8 053

/16

1110

MfTU n,M

JGFT RH TOD.

R 054

pn

1 IPO

DCR L

fl 055

10

1 ino

ADD P

JRM* B RK+RN.

R (15ft

77

1140

MOU Km A

JSTflRF NEW RM'.

R 057

79

1150

MOU A>C

JRFTRIEUE BM.

8 0S8

90

1160

SUE B

iRN* = RM-RN.

8 059

fiC

1170

INR L

8 OSA

77

UBO

MOU K#A

J STORE RM*.

INR

L

;new pair.

0 ner

CP

50

an 80

t onn

J1\I7.

PA I

a ntp

0 1 n

R nsF

1 PPO

wCOMPUTATiaw OF FFT. PASS 2 THRU N.

R n5F

1 P3 0

f)SF

FPfiSS

yvi

A* 64

;SFT UP PARAMFTFRS

p

_

1 P5 0

STA

CFLNUM

; FOR ND. PF CFLLS#

3P

OF

R3

1 P60

STA

DELTA

: ANGLE.

R 067

3F

OP

1 P7 0

MUI

A^ ?

; * FOR

8 069

3P

OC

83

1 P8 0

STA

PAIRNM

; PAIRS/CELL.

R 06r

3R

OD

83

1P9 0

STA

CELDIS

J SPAN PETWEFN PAIRS

B 06F

1300

NPASSICALL

SCALE

J KEEP DATA IN RANGE.

3A

OP

83

1310

LDA

CELNUM

J GET NO* DF CELLS t

8 075

„_

OA

83

13R0

STA

CELCT

t PUT INTO CELL CTR.

R 07R

PI

00

RS

1330

LXI

H»REAL

R 07P

PP

0 0

R 3

134 0

SHLD

RLPTl

SHLD

RLPTP

8 OR 1

P 1

0 0

R6

1360

l,X I

H,IMAG

R OR4

PP

04

fl 3

137 0

SHLD

IMPTl

8 0R7

PP

06

R3

t 3R 0

SHLD

IMPTP

R OR A

P 1

0 n

9F

1 39 0

NCFLL

LXI

Hj STADR

OR

R 3

SHLD

S INPT

R D90

3A

OC

fl3

1410

LDA

PAIRNM

;GFT PAIRS/CELL CTR.

8 093

47

14P0

MOV

n«A

8 094

PI

OD

83

1430

NCll

LXI

H*CELDIS

8 097

3A

DO

83

1440

LDA

RLPTl

IPTR 1 LSDY.

8 09A

86

1450

ADO

M

;ADD pair OFFSET.

8 09B

3P

OP

83

1460

STA

RLPTP

;SET UP BOTH

R 09E

3P

06

83

147 0

STA

I MPT ft

t PND PTES

8 OA 1

C5

PUSH

P

;SAUF PAIR CTR.

8 HAP

PA

08

R3

1490

LHLO

SINPT

R 0A5

7F

1500

A,W

;nFT SINF HE ANGLE

R 0A6

3P

1 0

83

1510

STA

SINF

; A SAVF.

R 0A9

3F

40

15P0

MVI

A#64

JADD COSINE OFFSET

R HAP

85

1530

ADD

L

; MODULO R56.

R OAC

6F

1540

Mfiy

L* A

8 OAD

7F

1550

MPV

A<M

JGFT COSINE OF ANGLE

8 OAF

3P

11

83

1560

STA

COSINE

J A SAVE.

8 oni

PA

OP

R3

1570

LHLD

RLPTP

;GET real PTR s.

8 0P4

4F

1580

MOV

C<M

J GET RN.

R np5

C5

1590

PUSH

D

;SAVF RN

R nP6

3A

1 t

R3

1600

COSINE

;get cosine.

R or'9

CD

7P

Rl

1610

CALL

MPY

;a b rn*cos(Z).

R ni^c

3?

IP

R3

I6P0

TPFAL

JSAVF PRODUCT.

n npF

r. 1

1630

pip

P

JGFT RM.

R ocn

.m

1 0

Rn

1640

SINF

R (irn

CD

7P

R 1

165 0

MPY

;A s RN45tN(7.1.

3?

1 3

R3

166 0

STA

TIMAG

JSAVE PRODUCT.

H nro

PA

06

R 3

1 67 0

LHl P

IXPTP

1 6R 0

■

c.y.

;get in.

„ I.

E

P

I SAVE IN.

OCE

3A

I 0

i7nn

SINF

8 oni

CD

"!«

01 «i

1T 1 n

TALL

MPY

;A = IN*S1N(7.) .

R 0D4

PI

IP

"3

lion i^^n

1 y I

H,TRFAL

R 0D7

R6

Ann

K

8 ODR

77

\vjn

vT)\j

Mj. A

;tr = RM*rns + in*sin.

8 0D9

C 1

POP

P

;(1FT

R OPA

3A

11

R3

176 0.

ensINF

R ODD

CD

7P

8 I

_ ■ ,

MPY

J A = I w^rPsc?, 1.

R OFO

P 1

13

83

i7Sn

1 XT

HiTIMAR

P nF3

96

i7an

SUP

M

R OF'i

77

innn 1h?b

K»A

;ti = iN*cns - nN*siN.

8 0F5

"en

00

83

iB^n

RLPTl

7F

MOV

A*M

J GET RM.

R 0F9

flF

ifi/n

mou

Cj A

J SAVE RK.

3A

IP

83

iBRn

LDA

TRFAL

1 tt* n

ADD

r

n nc-v

iHTn

y, A

;nx' B RM+TR.

1880

ry"i

A, C

IGFT RM.

8 OFO

91

IP

1890

H,TPKAL

R OFT

96

190 0

M

''A

OP

R3

19 10

1 tn n

RLPTP

R OF?

77

■

K*A

JRH" s> BM-TR.

1930

.

IMPTl

_

I ^

MOV

A*M

;get im

a nrr

MOV

C«A

;SAVE 1«

3A

13

83

Joan

LDA

TIMAG

8 10 0

8 1

ADD

C

R 1 01

loan

MOV

M*A

JIM' " IM+TI.

onnn

MOV

A«C

JGFT IM.

e 1 na

01

13

oni ft

LXI

H*TIXAG

1

Q

96

POPO

SUP

M

R 1 17

PA

06

83

I.HLD

IMPTP

^ 1 TA

77

MO^

M* A

JIN' » IM-TI

n 1 [>n

R 1 HP

P 1

08

83

P060

LXI

H*SINPT

P ITF

3 A

OF

83

P07 0

LDA

DELTA

R 1 1 1

R6

PORO

ADD

M

MNCR. PTR ANGLE PY DELTA

R 1 1 P

77

P090

MOV

M*A

00

83

LXI

H*RLPTl

R 116

34

PUO

INP

M

R 117

PI

04

83

PIPO

LXI

H>IMPTl

R 1 lA

34

P 130

INR

M

R I IP

C I

P 140

PDF

P

R 1 1 C

nfi

PI50

ncR

P

;DECREMENT PAIR CTR.

R I 1 D

CP

94

n n

P16f!

JNZ

NC 1

« 1 pn

P170

R IPO

PI

no

R3

PIRO

LXI

Hj RLPTl

J GET PTRS *

R 1P3

3A

nn

R3

R190

LDA

CFLDIS

R IPf

R6

PPOO

ADD

J ADD CELL OFFSET.

8 1P7

77

ppin

MCKJ

M* A

8 IPR

3P

04

R3

S2R0

STA

IMPTl

8 I P.P

PI

OA

83

RP30

LXI

H* CELCT

8 IPF

35

flP4 0

DCR

M

JDECR. CELL CTR.

8 IPF

CP

8A

RO

PP50

JNZ

NCFLL

R 13P

ppfin

R I3P

PP7 0

;;cHAMnF fapakfters for mfxt PASS.

R 13P

PPflO

8 1 3P

PI

OP

R3

PR9 0

NPl t

LXI

H*CELNUM

Listing 1 continued on page 460 May 1981 © BYTE PubUcatoiu Inc 459

Listing 1 continued:

R I n5 7F

R I .Ifi /^7

8 1:17 IF

«I3R P7

iri30 77

RI3A CR

8 13P S3

R I3C 7E

fl I3I> R7

«I3F 77

S13F R3

R l^in 7F

R |/| 1 HI

R 1 '1

77

R 1 '11 7 F

WIS /17

Rl^tf- IF

RU7 7 7

RMR C3 81/iP R I4P P I/iP R I'lP R I/IP

R WiP (11

fl IiF M

RISl PI

R Ifi/i flA

R ISS fi.l

RI5f FF

Hl^H PP

RISn FF

IftP DP

Rlf<0 19

R161 n/^

P Ifi/J CO RIA5 PI

Rir.R n/i R if.9 ni

R IfiC PI R If-F nA R 17n FF R 17P TF 8 17 3 IF R174 OP 8175 03 R176 19 fl 177 DA R 17fl 09 R 17P 8 17B 8 17P 8 I7P R I7n 8 17P R I7P 8 17P 8 17P BI7B 5F

8 I7n s I7r: AF

8 17n it! 8 I7F 57 817F 67 fl 180 6F 81SJ 7P 818R FF 8 184 FP. 8 187 7A R188 PF R 1R9 57 RIRA 79 RIRP FF 8IRD FS R 190 78 8191 PF 8 19P /l7 8193 3F 8 195 FS 8 196 8 196 78 8197 FF 8 199 3F 8 19A IF B)9B A7 R 19C 79 f 190 IF R 19F iiF R 19F 8 19F R 19F DP Rl/^P 19 8 1A3 81A3 FP R 1 M P9 R 1A5 FP R 1 fi(. R 1 A6 F 1 R 1A7 2U R 1 AB CP R 1 An R lAP 8lAP 29 8lAC 7C 8 IAD C9 8 lAE 8 lAF 8 lAF R lAF R1AF 06 R IPft PI R1P3 11 81P6 4F 81P7 OA 81 PR IP RIn9 PC 8IPA IC

R inn CP

RIPF PI 8IC1 11 8 1CA iiF

no 85 FF FF FF ni

fid Rl 65 Rl 5/1 81 OF R3

no ns FF ni

on

8A SI

00 85 7F R7

P6 81 0{) 86 7F 87

pni 0

P3P0 P330 I>34D P3SD P360 P37 0 P38 0 P39n P4 0 0 P/l 1 0

P/i/fO

p/isn

P/| 6 0 P/17 0 P/t8 0

pfl9n p5no

P510 P5P0

p5no P5/in

P5^iO

ps7n PSRn P59n

P61 n P6pn

P630

PfiSO PfifiO P67fl

p6Rn P69n P7nn P71 n P7pn P7 3n

P7fl0

P75n

P760 P77 0 P78 0 P790 P800

PR in

PRsn

PP30

pR/i n

PRSO

PS60 PR? n RB80 RS90 S900 P91D P9HD ?930 P94 0 R95n 8960 P97 0 P9S0 ft990 3000 3010

3npn

3030 3040 3050 306Q 307B 308 D 3090 3100 3110 31P0 3130 3140 3150 3160 3170 3180 3190 3P00 3PI 0 3PR0 3P30 3PflO 3P5 0 3P60

:iP7 0 npBQ

3P9 0 330 0 3310 33P0 3330 3340 3350 3360 3370 3380 3390 34 0 0 34 10 3flP0 3430 344 0 3450 3460 3470 3480 3490 3S0O 3510

A>M

f\

;CLFAP CY & SHI FT

RAR

; RIGHT TD HALVE NCI. CFLLS*

qra

f\

JSFT FLAOS*

MOV

M«A

R2

J OUT np CFLLS -> ***FIN1SH**#

[NX

H

iPAIRMM*

MOV

A«M

ADD

A

JTWICF AS MANY PAIRS

y.m

M> A

I NX

H

;CFX.DIS*

r^nu

n.M

ADD

A

JTWICF AS FAP APART.

f^W

M» A

INX

H

JDELTA

MPy

A*M

ANA

A

JCLFAR CY * SHIFT

PAP

J RlftHT TO HALUK THK ANRLE

MRU

»*A

JKP

NPA5S

;JSnAI.F nVFR-RANGF DATA.

;SCALF RFAL A II-Afi IF -5P > ANY DATA ;Nn RFGISTFRS PRFSFRVFn.

SCTALFiLXI

P/PFAI.

;5FT UP TAPLF PTR

LXI

n, - 1

1.x I

H. r> I p

1 ;Nn. OF PTS - 1

sri.p:

l.DAX

p

;r.FT PATA.

I NX

p

;pu.r>p PTP.

CPI

-5P

JTFST LPV/Fh- LIMIT.

JNC

5C1-3

;SKIP TP NFXT PT.

CPI

5P

;tfst uppfr limit.

JNC

SCL/t

JSCALF ALL IF OUT HIF PANfiF.

Sr.L3l

HAD

n

JTFST NFXT PT

JC

SCLP

PKT

;nnNF TFSTiNfi.

srx/ii

LXl

H^SCLFCT

INP

;PUMP SCALF FACTDR CDUNT.

L.XI

P,PFAL

;SFT UP TAPLF PTR.

LXI

H. 51P

1 ;Nn. RF PTS - 1.

.sc:l6:

LDAX

P

JGKT DATA,

CPI

Rnn

: TFST CIGN f.

cxn

; FXTFND IT TO CY

RAR

JDiyiDF PY P.

STAX

p

JRFTURN DATA TO TABLE

INK

n

JPUMP PTR.

DAD

p.

JNFXT PT.

JC

SCL6

RFT

iOONF SCALING

;;sinNFD multiply pQutinf.

JFXTFHNAL nFR. USAGFl- A <- tG# JIMTFPNAL PFG. USARF:-.

; HL = plinnucT (MspyjLSBYI.

: DF = MULTIPLirANp. ; PC = KULTIPLIFHJNO RFGISTKRS PRFSFPVFH.

MPY!

F.A

jpuT Anni r.MTn kliltiplicand

:ARnp ALRVADY IN >!ULTIPLIFR

XR/\

A

t^nu

P*A

ICLFAR MSPY'S.

xnu

P.IK

MOV

H«A

JCLFAR PRDDUCT

Mnv

L,A

xnv

A.F

iGFT LSnY HF MULTIPLICAMD.

CPI

0

jp

MPYl

INF.GATIUF KULTIPLICASn?

KOI

A*D

CMA

JFXTEND SIGN TO MSPY.

MOV

D*A

MPYl:

.^OV

A^C

IGFT LSPY np MULTIPLIFR.

CPI

0

JP

MPVP

;NFnATIVF XULTIPLIFR?

Mnv

AjP

CKfl

JFXTFNn NFG TP MSRY.

KOV

P* A

MPYRl

MVI

A< IS

)SET ITERATION CTR

Mpyj!

PUSH

PSW

J < SAVE.

JARITH. SHIFT MULTIPLIER RIGHT (SO

wnv

A<P

CPI

flOH

CI^C

;MAKE CY = MSBIT.

RAR

n, A

rm

A, C

RAR

;lsrit->cy.

C» A

;TFST MULTIPLIER LSPIT * IF SET*

; Ann MULTIPLICAND TD PARTIAL PRnDOGT

DAP D

;ARITH. SHIFT MULTIPLICAND LFFT CDF). MPY4t XCHG JSWAP MULTIPLIER S. PROD

DAD H JSHIFT LKKT.

XCHG JRFSTnpF PPGS.

;CHECK Lnnp cth. pnp PSW

ncp A ;nFcnFMFNT chunt.

jn;^ MPY 3

jDivmE 16-niT PimnucT nY \p.h sn that

i SINE & CaSINF AMPLITUDE = UNITY. DAD H iSHlFT-IN MSPIT OF

MOV A#H J LSPYTE A BFTUHN IN ABET

;;P0UEB CALCULATION* ;N0 REGISTERS PRESFRUED

POUFR:MVI LXI LXI

PWR1: MPU LDAX STAX INR INB JNZ LXI LXI

pvmsi Mtiv

Pi.>SGAnn

H* REAL D,PAPUF

; c=nFAi..

;A=(nFAL>P)/64. ;STORE.

PURl

H*IMAn J RESET PTBS. D.PAPUF

C*M IC-IMAG

8 1C5

OA

35f?0

LDAX

B JA=tIKAGt RJ/64

R ICfi

FP

3530

XCHG

R 1C7

R6

3540

ADD

M »A=tBFAL*P + IMAG»P)>'64'

a ICR

DP

CD

R1

3550

JNC

r+p

R ICP

3F

FF

3560

KVI

A* OFFH J A SATUHATFS AT O.FFH

R icn

77

357 0

MOV

y*A ISTOBF POHFB

1CF

FP

3SRn

XCHG

ICF

PC

.159 n

INP

I.

H 1 nn

1 C

3f-(lfl

INH

R 1 ni

CP

04

R 1

' ^

J^J7;

PUPP

R 1P4

r9

^^^^

?1FT

R 1D5

R IPS

„ / .

J;F1LL INPP V;iTH in.666 H?: SPUAF-F WAUF

8 1P5

3650

8 1D5

fl t

0 0

84

3660

VAVF: LXI

H»INPD

8 IDR

OF

PP

367 0

WUI

C*43

8 1 DA

cn

FA

R 1

36R D

WAVEPiCALL

LH

8 IDD

nn

F5

R 1

3690

CALL

HI

R IFO

fip

37 0 n

DCR

V.

R 1 F 1

CP

DA

Rl

37 1 n

JNZ

R 1 F/i

C9

37 pn

PFT

R 1F5

37 3tl

R 1E5

374 tt

APC FCU

1 17

8 IF5

37 5 0

KIP ECU

1P8

R 1E5

3F

E5

376 0

HI: MVI

A/KIP+APC

R 1F7

C3

EC

R 1

377 0

JMP

r + p

8 IF.A

3F

OP

378 0

Lfl! KV1

A*KID-APC

MVI

P*3

8 IFF

77

3R0 0

WAUF3iM0U

M*A

8 IFF

P3

3810

I NX

H

R IFO

05

38 PO

DCR

B

R IFl

CP

EE

fll

3830

JNZ

WAUF3

R lE/l

C9

3R40

PET

R 1F5

riRsn

A PC

37R 0

PPw'^

^^^^

1 HQ n

R OTP

'

nqon

1 Ton

no/ r

1 00 n

1430

fll 9 0

CELNU

RTnn

noon

1P50

1310

Sfi9n

CLEAR

Rni I

i^r r

c ns IN

J

noQn

176 0

DELTA

„_ P

1 ofin

P07D

EFT

ROOT

F PASS

R05F

H I

R 1 F5

1690

376(1

I >^AG

037 n

06 3 0

I >:pt 1

R 3("i

niR n

1 37 0

1910

PIPD

1 MPTP

R3n6

n 19 n

1 3R 0

Wi7 0

1670

INPD

«4 0t)

D35n

0700

3660

LO

81EA

36R0

37R0

KID

OORO

3750

376 0

3780

MHVl

RCPO

07P0

077 P

wnvF

8D1A

0700

KPY

R17P

1610

1650

1710

1770

MPY I

RIRA

P9R0

30Pn

«PYP

R 193

3040

3080

MPY 3

8 195

3 090

33 0 0'

MPY4

R 1A3

3P1 n

3P4 0

NCl

Rn94

14 3 0

PIfiO

NCFLL

RORA

139n

PP'ifi

NPI

R13P

PPQO

W PASS

R n6F

1300

P/i9 0

PAl

Rdsn

1 PRO

i?n n

PAPUF

877F

03R5

n4Pfi

3500

PAIPJJ

R30C

np30

IPRO

1410

PASSl

8 D4A

1060

pnwFP

RIAF

0470

34 00

PV)P1

81P6

3/" 30

348 □

PVfRR

81C4

3510

3610

REAL

R5on

036 0

0710

0810

08P0

PLPTl

8300

0 160

1340

1440

18P0

PLPTP

R30P

0 170

1350

1460

1570

':■ rr.i.F

« 1 /iP

1 060

1300

P5SQ

r. n.r

n 1 5/1

P5R n

P650

v.\.?.

P6 I n

pr,/j n

z< n.'i

R 1 6S

pr^3 n

pf.7 n

SCLf-

« 1 f, F

P7 1 n

P7't n

S CLFC

R30F

ppf- n

06 0 0

P67 0

5 I NF

R3 I n

npR 0

15 10

16/lP

1700

.■JINPT

R3n«

npon

wion

149 0

P060

S OADP

9Fn(l

01 ?n

3/10 0

S TADH

9FO0

0130

139 0

SWAP

8 041

096 0

SUPl

8P4f

0950

1010

T IMAR

8313

031 0

1660

1780

1970

TREAL

831P

030 0

16Pn

17PD

1850

WiSVF

RID5

0430

366 0

V AVE?

«IDA

368 0

3710

WAUF3

9 IFF

38 00

3830

RRSO P030

1070 PlOO 1910

1330 SIRO

H560 P690 3<10

Text continued from page 458:

I intend to write a subroutine to compute amplitude spectra following the method pointed out by Bob Leedom. (See "Approximation Makes a Magnitude of Difference," June 1979 BYTE, page 188.) This routine does not appear in listing 1, except as a comment.

Pass 1 of the FFT requires a trivial amount of computer arithmetic. Pass 2 is fairly trivial too, since sine and cosine have only the values —1, 0, and 1. Therefore, a simple way to increase the speed of the program would be to largely duplicate the coding of passes 2 thru N (inserting constants instead of variables and using a new sine/ cosine table {0,1,0,-1,0 }, etc). A special multiply subroutine could be used for this: a subroutine that can multiply only by 0,1, or — 1, but do it very quickly. This could shave up to one second off the transform time.

460 May 1981 © BYTE PubllcaHons Inc

Listing 2: Object-code listing in hexadecimal format of the assembly-language program given in listing 1. The /BC at the end of this listing is a checksum of the whole code.

8 0 0 0

CD

D5

8 1

CD

OC

8 0

CD

AF.

8 1

C3

E4

AF

3F.

0 0

32

OF

8 01 (1

83

S1

0 0

86

36

00

2C

C8

14

80

11

0 0

84

21

0 0

85

R OR0

1A

D6

8 0

77

1C

2C

CS

20

8 0

11

0 0

85

21

0 0

85

06

8 03 0

OR

7 D

1F

4F

7 B

17

5F

79

05

C2

32

8 D

TP

BB

DA

46

8 04 0

8 0

A F.

1A

77

79

1 P.

PC

C2

2F

8 0

CD

4B

81

1

0 0

85

0 n n

o u 3 U

7 F

4F

PC

46

SD

8 0

77

7 9

9 0

PC

77

PC

C2

5 0

8 0

3E

8 fl 6 0

4 D

3 S

0 D

8 3

32

n F

8 3

3F

0 P

3 P

0 C

8 3

32

0 D

8 3

CD

8 07 0

4P

8 1

3 A

OP

8 3

3P

OA

8 3

P 1

0 0

8 5

PP

0 0

8 3

P P

0 ?

8 08 0

8 3

P 1

0 0

8 6

P2

0 4

83

P P

06

8 3

P 1

0 0

9F

PP

OB

8 3

8 09 0

3A

DC

8 3

47

P1

OD

8 3

3A

0 0

S 3

8 6

32

0 2

8 3

3P

0 6

8 OAO

83

C5

2A

08

83

7E

3P.

1 0

83

3E

4 0

85

6F

7E

32

11

8 OBO

8 3

8A

0 S

8 3

4E

C5

3A

11

83

CD

7B

8 1

32

12

83

C1

o 01*0

3A

1 0

83

CD

7R

8 1

32

13

8 3

2A

06

8 3

4 F

C5

3A

1 0

8 ODD

83

CD

7P

8 1

P. 1

12

83

86

77

C 1

3A

1 1

8 3

CD

7B

8 1

8 OF0

P1

1 3

8 3

96

7 7

PA

0 0

8 3

7 E

4E

3 A

1 P

8 3

R 1

7 7

8 OFO

P1

1 P

8 3

96

PA

0 2

8 3

77

2A

04

8 3

7 F

4 F

3 A

1 3

R 3

8 10 0

8 1

77

7 9

P 1

1 3

8 3

96

PA

06

5 3

77

P 1

08

8 3

3 A

0 E

8 110

8 3

86

77

P 1

0 0

8 3

34

P 1

04

8 3

34

C 1

0 5

C P

94

8 0

8 120

1

0 0

83

3A

OD

8 3

86

7 7

3P

04

8 3

P1

0 A

8 3

35

r*o

Lf ri

8 130

8A

8 0

S1

OB

a o

no

7E

A7

i P

Cl f

r*a

ucs

<r>o

1 C

ai

r

11 1 1

c o

8 14 0

IV

I r.

n f

f 1

O "5

CO

1 V

1 r.

1 IT

T7 f 1

\j J

6F

o u

0 1

0 0

85

FF

FF

P 1

FF

0 1

OA

03

FE

cc

DP

6 0

R 1

FE

34

DP

65

8 1

8 160

19

DA

5-^1

8 1

C9

P 1

OF

R3

34

D 1

DO

85

PI

FF

0 1

OA

8 170

FE

80

3F

IF

OP

03

19

DA

6F

R 1

C9

5F

AE

47

57

67

8 180

6F

7E

FE

on

FP

R A

8 1

7 A

PF

57

79

FE

00

FP

93

8 1

8 190

78

PF

47

3F

OF

F5

78

FE

3E

IF

47

79

IF

4F

D2

8 lAO

A3

8 1

19

FP

P9

FP

Fl

3D

CP

95

8 1

29

7C

C9

06

9E

8 IRO

PA

00

85

1 1

7F

87

4E

OA

IS

PC

IC

CP

P6

81

21

00

8 ICO

86

1 1

7F

87

4F

OA

EB

86

D2

CD

81

3K

FF

77

EB

2C

8 IDO

IC

CP.

C4

81

C9

21

00

84

OE

2B

CD

EA

81

CD

E5

81

8 lEO

OD

C2

DA

81

C9

3E

F5

03

EC

81

3E

OB

06

03

77

23

8 IFO

05

CP.

EE

81

C9

/BC

Listing 3: Listing in hexadecimal format of the two'scomplement square table and sine table used by the FFT program.

on

on

nn

00

00

00

01

01

01

01

02

OP

OS

03

03

04

9^1 0

05

ns

06

06

07

08

08

09

OA

OP

OP

OC

OD

OE

OF

9KS0

1 0

1 1

IR

13

14

15

17

18

19

lA

IC

ID

IF

RO

PI

P3

9F30

p/j

R6

P7

?9

RA

PC

PF

PF

31

33

3 5

36

38

3A

3C

3F

9F4n

4R

44

46

48

4A

4D

4F

51

53

56

58

5A

5D

5F

6R

9F50

64

67

69

6C

6E

7 1

74

76

79

7C

7F

81

84

87

8A

8D

9E6 0

90

93

96

99

9C

9F

A3

A6

A9

AC

EO

P3

B6

PA

PD

Cl

9E7 0

C4

C8

OR

CF

BP.

D6

DA

DD

El

E5

E9

EC

FO

FA

F8

FC

9E8 0

FF

FC

F8

■FA

FO

EC

E9

F5

El

DD

DA

D6

DS

CF

CP

C8

9E9 0

CA

Cl

PD

PA

P6

D3

BO

AC

A9

A6

A3

9F

9C

99

96

9 3

9KA0

90

8D

8A

87

84

8 1

7F

7C

79

76

74

7 1

6F

6C

69

67

9EB0

64

6P.

5F

5D

5A

58

56

53

51

4F

4D

4 A

48

46

44

4R

9KCn

40

3E

30

3A

38

36

35

3 3

31

PF

PF

PC

PA

R9

P7

P6

9EDn

PA

?3

Rl

RO

IF

ID

IC

lA

19

18

17

15

14

13

IP

1 1

9EF0

1 0

nF

OF

OD

OC

OB

OP

OA

09

08

08

07

06

06

05

05

9EF0

04

04

03

03

OR

OS

OS

0 1

0 1

0 1

0 1

00

on

00

00

00

9F0O

00

03

06

09

OC

10

13

16

19

IC

IF

2R

S5

P.8

P.B

SE

9F10

31

33

36

39

3C

3F

41

44

47

49

4C

4E

51

53

55

58

9FS0

5A

5C

5F

60

6P

64

66

68

6A

6E

6D

6F

70

71

73

74

9F.T0

75

76

7B

79

7A

7 A

7P

7C

7D

7D

7F

7F

7F

7F

7F

7F

9F4 0

7F

7F

7F

7F

7F

7F

7F

7D

7D

7C

7P

7A

7A

79

78

76

9F50

75

7/1

7 3

7 1

7 0

6F

6D

6P

6A

68

66

64

6P

60

5F

5C

9F6n

5 A

5R

55

53

5 1

4F

4C

49

47

44

41

3F

3C

39

36

33

9F7 0

31

RF

RP

R8

R5

P.P.

IF

IC

19

16

13

10

OC

09

06

03

9F8 0

no

FD

FA

F7

F4

FO

ED

FA

E7

E4

El

DF

DB

D8

D5

DH

9F90

CF

CD

CA

C7

CA

Cl

PF

BC

B9

B7

B4

Df>

AF

AD

AB

A8

9FA0

A6

M

AR

AO

9E

9C

9A

98

96

95

93

91

90

8F

8D

8n

9Fro

RP

8A

88

87

86

86

85

84

83

83

BP

8R

BP

8 1

8 1

B 1

9FCn

H 1

B 1

8 1

8 1

BP

BR

ap

8 3

83

84

85

86

86

R7

88

8A

9FDn

BP

8C

BD

BF

90

9 1

93

95

96

9B

9A

on

9F

AO

A?

A4

9FF0

A 6

AB

AP

AD

AF

BP

P4

P7

P9

BC

DF

C 1

C4

C7

CA

CD

9FF0

CF

DP.

D5

D8

DP

DF.

El

F4

F.l

FA

ED

FO

F4

F7

FA

FD

/5F

The 8080 program in listing 1 has been dumped out in hexadecimal format with checksum and appears in listing 2. The sine and square tables appear in listing 3. The equations used to define the tables are:

Two's-complement square table:

•Table entries are unsigned 0 thru 255 •Table index 1 = 0 thru 127 (two's complement 0 thru 127) Table (I) = INT (((1 t 2)/64) +0.5) •Table index 129 thru 255 (two's complement -127 thru -1) Table (I) = INT ((((256 -I) t 2)/64) + 0.5) • Table index 128 ( two's-complement —128) Table (128) = 255 (not exact value of 256)

Two's-complement sine table:

•Table index I runs from 0 thru 255 •Table (I) = INT(0.5 + 127*SIN((I)*2*PI/256)) where PI = 3.1416

An optimization of the 6800 FFT would be to replace lines 285 thru 287 inclusive by the single instruction ASR A. This has been incorporated into the 8080 program, but it makes a negligible difference because there is no single 8080 instruction equivalent of the 6800 ASR A instruction (arithmetic shift right, A accumulator). The test power spectrum produced by the 8080 FFT program is printed out in listing 4.

Listing 4: Test power spectrum produced hy the 8080 FFT program in listing 1. The waveform is a square wave with a period of six data points. The first byte is 0 frequency.

8 77F

0 1

n 1

0 1

0 1

n 0

0 1

nn

n 0

on

no

0 0

0 1

0 0

0 1

no

00

R78F

no

00

00

00

00

on

nn

00

no

00

00

0 0

00

no

no

on

879F

00

00

on

00

oo

00

01

01

ap.

03

in

3C

03

01

0 1

00

R7AF

00

00

on

nn

00

00

00

00

00

00

00

00

no

00

nn

00

8 7PF

00

00

no

on

on

00

00

00

00

00

00

00

nn

on

nn

on

R7CF

00

nn

nn

00

on

00

00

00

00

on

00

00

00

00

on

00

R7DF

no

nn

no

on

00

00

no

00

00

00

00

00

00

00

00

no

R7FF

00

00

no

no

00

00

00

00

00

00

no

00

00

on

00

0 0

8 7FF 13 /7R

Richard Lord Replies

Mr Roxburgh is indeed correct about the possibility of overflow with my scaling routine. I tried slowly increasing the amplitude of a square-wave input and discovered that for amplitude pairs of ± hexadecimal IB, IF; 33, 3F; and 6A, 6E the algorithm produces overflow artifacts. This did not show up in initial testing because integral binary amplitudes (10, 20, 40) were used. The scaling routine immediately fixes these values before overflow has a chance to occur. For sampled audio, this overflow has undoubtedly introduced errors. Insertion of new limits, as Mr Roxburgh proposed, fixed the overflow problem so that the FFT yields correct results at all amplitudes. My thanks to Mr Roxburgh for pointing this out. I hope that this has not created too many difficulties for anyone who has been using the FFT previous to this discovery.

Many letters have come to me in response to this article and the response has been very gratifying. Most of the letters have been requests for the 6502 verison which I never got around to writing. (At this time I'd be more inclined to try a 6809 version.) Quite a few readers suggested great improvements to the "sum of absolute values" method, and one letter pointed out that the SIN table is actually a — 1*SIN yielding inverted imaginary terms. All these improvements are greatly appreciated. ■

May 1981 © BYTE PubUcadoni Inc 461

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462 BYTE May 1981

Circle 236 on Inquiry card.

What's New?

Handy Pocket Computer Uses BASIC

Sharp Corporation will announce the introduction of its PC-12II Pocl<et Computer into the American marl<et at this month's National Computer Conference (NCC). Measuring only 17.5 by 7 by 1.5 cm (6% by 2% by '%2 inches), the battery-powered PC-I2n contains BASIC in ROM (read-only memory). A 24-character LCD (liquid-crystal display) can be used to show program lines, prompt the user for input from the keyboard, or display results. The unit's typewriter-like keyboard includes a calculator-type keypad. The PC-12I I's memory can hold up to 1424 program steps and 26 data variables, or prpgram memory can be used for data (eight steps are equivalent to one variable). Information in memory is retained even when the power is off due to a memory safeguard circuit.

The PC-1211 uses a reservable key system, making it possible to assign a key for a frequently used function or command. Reserved keys provide one-key recall during both manual calculation and programming. In addition, a definable key system fixes 18 programs for each key, allowing the user to recall and run each program at the touch of the proper key. Transparent templates that fit over the keyboard portion of the unit are included to allow labeling

SYSTEMS

of reserved and defined keys.

The BASIC interpreter has the more common BASIC commands and functions, as well as DEBUG, PRINT USING, BEEP, ASN (arcsine), ACN (arccosine), EXP (e*), and more. Editing functions allow left and right cursor shifting, insertions and deletions, and scrolling up or down. Subroutines and FOR...NEXT loops can be stacked to four levels, and 15 levels of parentheses can be maintained. An 80-character input buffer and multiple statements per line allow easy program entry. A ten-digit mantissa and two-digit exponent are used in all calculations. Four mercury batteries provide approximately 300 hours of operation, thanks to the automatic poweroff feature. An applications manual containing 134 programs in ten application areas such as math, statistics, civil engineering.

and electrical is included. Each program is accompanied by a description of how it works and a complete list of variable assignments. A beginner's BASIC book is also included in the package.

Also being introduced at NCC are two peripherals for the PC-I2n. The CE-I21 Cassette Interface allows programs, key assignments, and data to be saved or loaded to or from a cassettetape recorder. For hard-copy output, Sharp has the CE-122 Printer/ Cassette Interface. In addition to the cassette-interface functions, the CE-122 features a 16-character dot-matrix printer capable of printing one line per second. The unit is powered by a rechargeable nickel-cadmium battery and includes a battery indicator that flashes when the battery becomes low.

The PC-121 1 will have a suggested retail price of S249. The CE-121 and the CE-122 will have suggested retail prices of S49 and S 149, respectively.

The PC-12II has been previously sold by Radio Shack as the TRS-80 Pocket Computer.

For more information on the PC-1211 Pocket Computer, the CE-121 Cassette Interface, or the CE-122 Printer/Cassette Interface, contact Sharp Electronics Corporation, 10 Keystone PI, Paramus NJ 07652, (201) 265-5600.

circle 500 on Inquiry card.

Master Controller Board

The Master Controller Board is a Z80-based single-board computer that can be customized for each application. Customization is accomplished by inserting various ROMs (read-only memories), programmable memories, and control integrated circuits as needed. All the I/O (input/output)

circuits are mapped into both memory and I/O address space. The board provides three ROM/ EPROM (erasable programmable ROM) sockets for up to 12 K bytes of riiixed ROM/EPROM. Also included are 2 K bytes of programmable memory, provision for up to 72 lines of parallel I/O, a keyboard controller, and an integrated circuit that provides

two serial I/O ports. Two counter/ timers and an arithmetic circuit can be added. The Master Controller Board costs S49.95 for a bare board, $99.95 for the minimum kit, and S199.95 assembled. Other options are available. Contact R W Electronics, 3165 N Clybourn, Chicago IL 60618, (312) 248-2480.

Circle 501 on inquiry card.

May 19B1 © BYTE PublicaUons Inc 463

Video and Audio on One Board

The Color Video Processor and Programmable Sound Generator board can create color graphics and sound. It contains 16 K bytes of I/O- (input/output) mapped video memory and allows graphics or text to be superimposed over an external video input. Using 16 colors with 35 display planes, a three-dimensional effect can be obtained. In addition, the board has three programmable square-wave tone generators' and two 8-bit programmable I/O ports. The graphics mode features 256 by 192 dot resolution. The board also allows real-time interrupts. The tone generators feature envelope generation over a range of 12 octaves. The singleboard color video and sound

generator uses the Texas Instruments T1\/1S9918A Video Display Processor and the General Instrument AY-3-8910 Programmable Sound Generator, and is compatible with Z80, 8085, and 8080 microprocessors on S-IOO bus systems. Documentation in

cludes programming examples and test routines. It is available for S475 assembled and tested or S375 in kit form. Contact Electronic Design Associates, POB 94055, Houston TX 77018, (713) 999-2255.

Circle 502 on inquiry card.

Q2000-Family of iHard-Disl< Drives

The Q2000 series of 8-inch fixed-hard-disk drives are compatible with Shugart's SAl 000 disk drives, but offer I0-, 20-, and 30-megabyte unformatted capacities. This is achieved by using a special head-positioning tech

nique. The Q2000 family features

a 4.34-megabit-per-second transfer rate, an average latency of 10 ms, and access times of 15 ms track-to-track, 100 ms maximum, and 50 to 60 ms average. IVIaximum recording density is 6600 bits per inch, and track density is 345 tracks per inch. Rotational

speed is 3000 rpm (revolutions per minute). Soft-sectoring is offered.

In OEM (original equipment

manufacturer) quantities of 500 per year, pricing is S1200 for the 10-megabyte Q20I0, SI500 for the 20-megabyte Q2020, and SI800 for the 30-megabyte Q2030. For more information, contact Quantum Corporation, 2150 Bering Dr, San Jose CA 95131, (408) 262-1100.

Circle 503 on inquiry card.

464 May 19B1 © BYTE PublicaUons Inc

What's New7

PUBLICATIONS

Inside BASIC Games

Inside BASIC Games, by Richard IViateosian, uses games as a frameworl< for teaching BASIC programming. Eight games, ranging from simple arithmetic to complex matching games, are described and analyzed so that readers can learn how to design their own programs, as well as play the game. The games are written for most microcomputers. Inside BASIC Games is a Sybex publication, and it costs $13.95. Contact Sybex Inc. 2344 6th St, Berkeley CA 94710, (415) 848-8233,

Circle 504 on Inquiry card.

Microcomputer Software Catalog

Creative Discount Software has released its Winter-Spring Software Catalog for the TRS-80, TI-99/4, and the Apple II and the Apple II Plus microcomputers. The catalog features professional, educational, and business software at discounts of up to 30%. Medical and dental office-management systems are also available. For your free copy, request catalog number 478, from Creative Discount Software, 256 S Robertson, Suite 2156, Beverly Hills CA 9021 I, (800) 824-7888; in Alaska and Hawaii, (800) 824-7919; in California, (800) 852-7777. Ask for operator 831.

Circle 505 on inquiry card.

Solutions from Serendipity

Serendipity Software Solutions features commercial-application software packages designed for 280 and 8080/8085-based microcomputers operating under CP/M. Among the products featured in the catalog are general-ledger accounting, commercial accounts receivable and payable, payroll, inventory control for retailers and manufacturers, and professional client billing. There is a S1 handling charge for the catalog. Contact Serendipity Systems Inc, 225 Elmira Rd, Ithaca NY 14850, (607) 277-4889.

circle 506 on inquiry card.

Supercap Series Catalog

NEC Elertron's Supercap catalog includes specifications, dimensions, applications, discharge characteristics, and lists of features for high-capacitance Supercap memory-backup devices. The Supercaps supply capacitances of up to I F [yes, one farad...RSSJ.

They feature a slow rate of discharge and can provide very low currents for approximately one week. The catalog is free from the Product Marketing hAanager for Capacitors, NEC Electron Inc, 252 Humboldt Ct, Sunnyvale CA 94086, (408) 745-6520.

Circle 507 on inquiry card.

Optoelectronics and Fiber-Optics Manual

A 286-page optoelectronics and fiber-optics data manual has been published by Motorola Semiconductor Products Inc. The manual provides device data sheets, selector guides, cross-references, and applications information. The manual includes gallium-arsenide infrared emitters, silicon detectors, opto-coupler/isolators, the family of opto-triac drivers, and Motorola's SCR (siliconcontrolled rectifier) couplers.

The manual's fiber-optic section is intended principally to address fiber-optic communications systems in the computer, industrial controls, medical electronics, consumer, and automotive applications.

The data book, Mototola Optoelearonics Device Data, costs S3.25. It is available from Motorola Semiconductor Products Inc, POB 20912, Phoenix AZ 85036, (602) 244-4306.

Circle 508 on inquiry card.

May 1981 ® BYTE PublicaliDns Inc 465

SOFTWARE

Two New Products from Commodore

Ozz—The Information Wizard lets users design data-management and retrieval systems. Ozz was created for the Commodore CBM 8032 microcomputer. The program allows users to set up formats, store information, perform calculations and global searches, design forms and documents, analyze Information, and access files.

Wordcraft 80 is a word-processing program designed for the 8032 system. Wordcraft 80 offers variable page layouts of up to 117 characters by 98 lines; screen display of finished-format documents; tabs, indentations, decimal tabs, columns; automatic centering and right-margin justification; automatic pagination, headers, and trailers; deletion and insertion of text: transfer of text from one page to another; merging of form letters with name/address files; handling of single sheets or continuous-form paper; sub- and superscripts: and automatic underlining and emboldening of text.

For more information on both products, contact Commodore Business Machines Inc, 950 Rittenhouse Rd, Norristown PA 19403, (215) 666-7950. Circle 509 on Inquiry card.

The Voice

The Voice gives the Apple II or the Apple II Plus the power of speech. The Voice's built-in vocabulary allows expression of many combinations of phrases, or the user can enter his own vocabulary and make the 48 K-byte Apple say anything. Floppy disks store up to 80 words or phrases tnat can laccr uc soilcu lur cjuiCN reference. The Voice allows any BASIC program to speak by using PRINT statements. The price is $39.95, from Muse Software, 330 N Charles St, Baltimore MD 21201, (301) 659-7212. Circle 511 on inquiry card.

A Stellar Trek

This high-resolution color version of the Star Trek game runs on the Apple II. Three different Klingon opponents and the Romulan Star Empire are pitted against the user. Users have many command prerogatives, including movement throughout the galaxy, use of starship weaponry, maintenance of energy reserves, repair of damage, and more. A Stellar Trek requires 48 K uyLc-3 ui fficifiuiy diiu /\ppicoUiL BASIC in ROM (read-only memory). The price is S24.95 on floppy disk. Contact Rainbow Com- , puting, 9719 Reseda Blvd, Northridge CA 91324, (213) 349-5560.

Circle 513 on inquiry card.

FORTH-79 for the Apple

MicroMotion's FORTH-79 conforms to the International FORTH-79 standard. It is suited for data acquisition, process control, animation, and video games.

FORTH-79 comes with a screen editor and macroassembler, and vocabularies for strings, double-precision integers, lowresolution graphics, and modem communications. The operating system allows for multiple disk drives and is 13- or 16-sector disk compatible. It runs on a 48 K-byte Apple 11 or Apple 11 Plus. FORTH-79 can be obtained for $89.95 from MicroMotion 12077 Wilshire Blvd, Suite 506, Los Angeles CA 90025, (213) 821-4340.

Circle 512 on inquiry card.

Combine Hard Disks and the TRS-80

HDOS-2 is a hard-disk operating system designed to be used with TRSDOS 1.2 on the TRS-80 Model II. The advantage of this softvyare is that it allows a Corvus hard-disk drive to be interfaced with existing software with only minor changes to the programs. HDOS-2 requires I K bytes of memory and allows use of multiple drives. The system costs $ 125. Contact Computer Program Associates, 15076 Beltway Dr, Dallas TX 75234, (214) 233-2039.

circle 514 on Inquiry card.

Atari Graphic Editor

Plot & Draw is a cassette-based graphics-generation and editing package that creates graphics in three colors plus a background. Video drawings can be created and saved on cassette. It requires an Atari computer with 8 K bytes of programmble memory and a joystick. The price is SI8 from Mosaic Electronics, POB 748, Oregon City OR 97045.

circle 510 on Inquiry card.

TFORTH TRS-80 BASIC, and a phoneme TFORTH is a fig- (FORTH assembler to support voice syn

Interest Group) standard version thesizers. TFORTH is supplied on of FORTH, extended for the 5-inch floppy disks for S130. ConTRS-80. It contains an operating tact Advanced Technology Corsystem, assembler, text editor, poration, 161 7 Euclid Ave, Knoxfloating-point mathematics ville TN 37921, (615) 525-1632. package, I/O (input/output)

package, graphics links into circle 515 on inquiry card.

466 May 1981 © BYTE Publications bic

INCREDIBLE? BELIEVE IT!

Odntex 1(100

PRINTERS

150 cps bidirectjonal-9x9 dot matrix, quietized case, 136 col, vertical form control and many other functions S11Q(;

We feel this printer offers * I I SO

the best price/performance ratio available. RS-232 serial to 19.200 baud supporting X-ON, X-OFF or Current Loop — add $40 ^^1^

' TjT ^ Teletype 40, 300 LPM-typewriter quality, RS- from $2495 232 interface. This qualify printer is available in many configurations including forms access, quietized case, etc. Teletype 43 from $995

NEC Spinwriter-55 cps, bidirectional, letter quality

R.O./tractors $2540 KSR/tractors $2795

DIABLO 630-40 cps, bidirectional, daisy wheel, plot/graph $2270

C. ITOH Starwrtter, 25 cps, daisy wheel Si 575

C. ITOH Starwriter, 45 cps, daisy wheel $1849

EPSON MX-80, 80 cps, 9x9 dot matrix $545

ANADEX 9500/9501, up to 200 cps, high resolution dot $1349

OKIDATA Microline 80,80 cps, 9x7 dot matrix $525

Microline 82. bidirectional, friction/pin feed $625

Microline 83, bidirectional, 120 cps, uses 15'' paper $995

11-810,150 cps, Basic $1695

Package-Compressed print, vertical form control $1830

CENTRONICS 704-9,180 cps, 9x9 dot matrix, 132 col, RS-232 $1595

704-11,180 cps, 9x9 dot matrix, 132 col, parallel $1695

730,100cps, 7x7 dot matrix, same as R.S. LRU $660

737,80 cps, nx9 dot matrix, same as R.S. LPIV $849 proportional spacing

DEC LA-34 $1085

S-100 SPECIALTIES

j^p California These high quality, reliable products have made CCS Computer defacto industry Standard for S-100 products Systems Assembled and tested: list only

2200 H.O. Mainframe, 20 a. P.S., 12 slot MB $434 $399

2065C 64K dynamic RAM/Bank Select $720 $580

2810A Z-80 CPU, serial port, ROM monitor $310 $259

2422A Floppy Cont, CP/M 2.2, ROM monitor $425 $345

CB2 Z-80 CPU $344 $295

2P + 28 I/O interface $290 $249

We can supply the full S-100 and Apple lines of CCS, SSM, NNC, MORROW DELTA, NORTHSTAR and GODBOUT at Similar savings.

^7

TERMINALS

TELEVIDE0 912C $950 $725

920 C $1030 $789

950 $call

S0ROCiai20 $995 $729

IQ140 $1395 $1149

INTERTUBE III or EMULATOR (multi-terminal) $call

OECVr-100 $2050 $1575 Similar savings for our HAZELTINE and LEAR SIEGLER lines

complete with each other and

ONLY $314

$425 $625

2 for $1190 $650

2 for $1250 $299 $415 $135 $963 $1259

5V4" DISK DRIVE SALE

MPI B-51 40 track, 102K Byte drives. These drives come enclosure and power supply. They can be mixed with Radio Shack* drives on the same cable. 90 day warranty

8" DISK DRIVE SALE

8"SHUGARTSA801R

Premium doublesided drives: 0" SHUGJtRT SA851R

QUMEDATATRAGKS

Enclosure, power supply for 2 8" drives (horizontal) A&T NNC industrial grade enclosure for 2 drives with P.S. POWER 1, power supply for 2 8" drives MORROW Discus 20 -i- CP/M® Discus 22-1-CP/M®

HARD DISK SPECIALS List only

CORVUS10MB and controller $5350 Scall

20MB and controller $caii

Constellation Network Multiplexer $750 $call

MirrorVideo Tape Disk Backup $790 $call

MORROW 29MB-I- controller + CP/M 2.2® $4995 $3995

CAMEO cartridge drive controller $1500 $1275

controller, CDC Hawk Drive (5 fix, 5 rem) $6995 $5995

controller, V\/esternDynex (5 fix, 5 rem) $5995 $5099 We carry the full line of KONAN disk and tape controllers and subsystems.

FULLY CONFIGURED BUSINESS SYSTEMS

The following are some examples of the fully assembled and tested business and scientific computer systems which we offer. All include CP/M 2.2, 64K bytes dynamic RAM. Z-80A 4mh CPU. We offer a full line of quality, tested software.

CCS 2210A w/floppy controller, 1 serial port $1849 CCS 300-1A w/1.2MB floppy drives, 2 serial, 2 parallel ports $4849 CCS 400-1A w/10MB hard disc, 2 serial, 2 parallel ports $6999 Optional CP/M for CCS 300,400 (OASIS available) $150

NNC 80 w/1 MB floppy drives, 2 serial, 3 parallel ports $3799 NNC SOW wASMB floppy, 8.4MB hard disc, (OASIS optional) $6693 ALTOS Single and multi-user systems Scall MORROW Decision 1, MICROSOFT basic, UNIX $eall

PERSONAL COMPUTERS

APF Imagination Machine, basic, color, sound, tape, etc. ATARI 400

800 with 16K RAM

$399 $512 $895

LOOK HERE!

NNC 2 board set Z-80A CPU, CP/M 2.2, floppy disc controller

2 serial, 3 parallel ports, PROM, I/O cable $765 SUPERBRAIN Scall OSBORNE book-keeping programs (unaltered, require C-BASIC 2) includes comprehensive documentation General Ledger, Payroll, Account Rec./Payable each $99

all three $250

TCS business software G/L, Payroll, A/R, A/P each $150

all four $500

ALL OF OUR PERIPHERALS CAN BE CONFIGURED FOR RADIO SHACK® MODEL 11

DEALER and INTERNATIONAL INQUIRIES WELCOME

WASHINGTON COMPUTER SERVICES

an affiliate of (//WASHINGTON))) est. 1912

INCORPORATED

CUSTOM COMPUTER ROOM WIRING SINCE 1960 97 Spring Street New York, N.Y.I 0012 Hours: 8AM-5:30PM (EST)Mon.-Fri.

TO ORDER: CALL OPERATOR FOR OUR NEW TOLL-FREE NUMBER. In N.Y. State and for technical Information call 1-(212) 226-2121

For fast delivery, send certified checks, money order or call to arrange direct bank wire transfers. Personal or company checks require two to three weeks to clear. All prices are mail order only. Prices subject to change without notice: call for latest prices. Prices include 2% cash discount. N.Y. residents add sales tax.

Radio Shack" is a trademark of the Tandy Corp [^<HI|(p^ CP/Mo> is a trademark ot Digital Research <Mimm: Ji^fjff

BYTE my 1981 467

What's New?

Link the TRS-80 with Other Systems

The Super-Host program allows any type of system to communicate with the TRS-80 Model I microcomputer. The program will configure itself to run under TRSDOS, NEWDOS 2.1, or NEWDOS-80. It keeps track of the date and time, even after reboot or system resets. One function of the program protects the user's own and any foreign system from unwanted control codes. Another feature allows users to customize transmissions to conform to other systems' standards and block out characters that might affect those systems.

Super-Host is a menu-driven program, so users can set up all system parameters. Other features are its lowercase driver, uppercase lock for incoming data, and independent uppercase lock on outgoing data. It has user-programmable nulls and line feed. TRS-80 computers with a printer can be programmed to maintain a printed record of callers who have accessed the system.

Super-Host is available for S29.95 from Programs Unlimited, POB 265, Jericho NY 11753, (516) 997-8668.

circle 516 on Inquiry card.

FORTH for Atari

This FORTH system for the

Atari 400 and 800 computers requires a minimum of 16 K bytes of programmable memory. The diskbased system has a screen editor and the capability to review and modify disk contents. Included with the program package is dictionary documentation and a customization guide. The system costs $50. For further information, contact Pink Noise Studios, 1411 Center St, Oakland CA 94607, (415) 465-1212.

Circle 517 on inquiry card.

SOFTWARE

Softstuff Software from Heath

reiaence manual

Heath's utility and applications programs in the Softstuff line include the General Ledger II on a floppy disk for use with the HDOS operating system or Heath's version of the CP/M operating system. The price for the program is SI24.95. The Small Business In

Software for Law Offices

Law-1 is a time-management and billing system for the legal professional. It features system and program security, client/matter and attorney reporting, accounts-receivable ledgers, ageing analysis, pre-billing worksheets, invoicing, and automatic file backup, and it performs otherthan-standard inquiries.

Law-1 is written in CBASIC for CP/M-based systems. It comprises 38 applications packages. The system is parameter driven and can support floppy- and hard-disk configurations. Different terminals are supported. A demonstration package is available for $75, and the single-user package price is S800. For further information, contact Microcon inc, POB 805, Amherst NH 03031, (603) 673-0230.

Circle 519 on inquiry card.

ventory program for HDOS systems is S69.95. The CBASIC language, a disk-based, noninteractive language with pseudocode compiler and run-time interpreter for CP/M systems is priced at $ 110. The BDS C compiler includes a linking loader, a library containing file I/O (input/output) and floating-point functions, and a library manager. The C compiler runs on CP/M systems and is priced at $119.95.

The Softstuff product line also offers the Microsoft MACRO-80 package, a full-screen editor, a sort program, and a network sys^ tern. For more information on Softstuff programs, contact Heath Company, Department 350-670, Benton Harbor Ml 49022, (616) 982-3210.

Circle 518 on Inquiry card.

Learn Trigonometry on the Compucolor li

Using a circular functions approach to trigonometry, these teaching programs provide experiences with radian measure, sine function development, graphing the sums of functions, drill with identities, and polar graphs. All programs encourage the user to explore functions under computer guidance, to recognize identities, and to notice patterns. Program listings are included, so users can create additional variations and drills. This disk for the Compucolor or Intecolor computers requires a 64- by 32-character screen with 127 by 127 color blocks in low- and high-resolution graphics. It is available for $29.95 from Metra Instruments Inc, 2056 Bering Dr, San Jose CA 95131, (408) 297-8530.

Circle 520 on inquiry card.

468 May 1981 © BYTE Publicabons Inc

COMPUTER STOP

ORDER BY PHONE MON.—SAT. 10-6

(213) 539-7670 PST

2545 W. 237 St. Torrance, CA. 90505 TELEX: 678401 TAB IRIN

LOWEST PRICES iN THE WEST.NORTH, SOUTH & EAST

[appiG computer

■ Sales and Service

.3850

.4350

.4800

APPLE///OPTION A:

APPLE /// 96K

Information Analyst Pacl<age 12" B/W Monitor

APPLE W OPTION B:

SAME AS OPTION A PLUS: DISK II for APPLE ///

APPLE///OPTION C:

SAME AS OPTION A PLUS: DISK II FOR APPLE /// SILENTYPE Thermal Printer

APPLE HARDWARE

Parallel Printer Interface Card 160

Communications Card 195

High Speed Serial Interface 175

Pascal Language System 425

Centronics Printer Interface 185

Applesoft Firmware Card 160

Integer Firmware Card 160

Disk ][ with Controller DOS 3.3 529

Disk]! only 475

Graphics Tablet 625

OTHER HARDWARE

Alf Music Synthesizer (3 Voice) 245

9 voice 175

ABT Numeric Keypad 119

Micromodem][ 295

Apple Clock 245

Rom Plus with Keyboard Filter 175

lntrol/X-10 System 250

Romwriter 150

DoubieVislon 80 x 24 Video Interface 295

CCS Arithmetic Processor 399

CCS Parallel Interface 119

16K Ram Card 195

Microworks DS-65 Digisector 339

SVA 8 inch Disk Controller ; 335

Sup-R-Mod 30

CCS Synchronous Serial Interface 159

CCS Asynchronous Serial Interface 159

Corvus 10 Meg. Hard Disk 4395

Corvus Constellation 595

MISCELLANEOUSISUPPLIES

16K RAM (200-250 NS) 49

Verbatium Datalife Diskette (Box of 10) 30

Dysan Diskettes (Box of 5) 22

Apple Diskettes (Box of 10) 45

Verbatim Diskette Boxes (Holds 50 Disks) 18

Silentype Paper (Box of 10 rolls) 40

APPLE ][ Plus

16K $1075

48K $1193

Disk][Drive..$529

with Controller & Dos. 3.3

PASCAL SYSTEM $425 Z-80 Softcard $299

MONITORS/DISPLAYS

LeedexVideo100l2" 140

Sanyo 9" Monitor 195

KG-12C Green Phos. Monitor 275

Sanyo 12" Green Phosphor. Monitor 275

NEC 12" Green Phosphor. Monitor 275

Sanyo 12" B/W Monitor 250

PRINTERS

Apple Silentype with Interface 525

IDS 445 (Paper Tiger) with Graphics 795

IDS 460 with Graphics 1199

IDS 560 with Graphics 10) 1695

Centronics 737 .■ 895

NEC Spinwrlter (RO, Serial) 2650

SOFTWARE

The Controller 525

Apple Post (Mailing List Program) 40

Easywriter Professional System 195

Apple Pie 2.0 95

DB Master Data Management 150

The Cashier 210

Apple Writer 65

Visicalc 125

CCA Data Management System 90

Full Screen Mapping for CCA DMS 59

Pascal Interactive Terminal Software (PITS) 29

Basic Interactive Terminal Software (BITS) 29

Data Capture 29

Data Factory DMS 95

Apple Plot 55

Apple Pilot 120

Magic Wand Word Processor (Needs Z-80 Softcard) 345

Dow Jones Portfolio Evaiuator 45

Fortran 140

ORDERING INFORMATION: Phone orders invited using VISA, MASTERCARD or bank wire transfers. VISA & MC credit card service ctiarge of 2%. AE credit card service charge of 5%. Mail order may send charge card number (include expiration date), cashier's check, money order or personal check (allow 10 business days to clear.) Please include a telephone number with all orders. Foreign orders (excluding Military PC's) add 10% for shipping. All funds must be in U.S. dollars (letters of credit permitted). Shipping, Handling and insurance In U.S. add 3% (minimum $4.00). California residents add 6% sales tax. Our low margins prohibit us to send COD or on purchase orders or open account (please send for written quotation). All equipment is subject to price change and availability. Equipment Is new and complete with the manufacturer warranty. We do not guarantee merchantlblllty of products sold. All returned equipment Is subject to a 15% restocking fee. We ship most orders witiiin 2 days.

WE ARE A MEMBER OFTHE CHAMBER OF COMMERCE. RETAIL STORE PRICES MAY DIFFER FROM MAIL ORDER PRICES.

PLEASE SEND ORDERS TO:

COMPUTER STOP, 2545 W. 237 St., TORRANCE, CA 90505

Circle 89 on inquiry card.

BYTE May 1981 4*9

What's New?

SYSTEMS

MT500 System

The MT500 microcomputer provides data- and word-processing capabilities for business and scientific applications. The MT500 features a video display, a Z80A microprocessor, the CP/M operating system, 64 K b3rtes of programmable memory, two 500 K-byte 5-inch floppy-disk drives, and a keyboard. Printers and modems can be attached. The MT500 has a suggested price of less than S6000. For details, contact IVIaatra Corporation, 1835 W Shryer Ave, Roseville MN 55113, (6I2J 631-3555.

circle 521 on Inquiry card.

Memory-Mapped S-100 Video Board

The VB3 is a memory-mapped board with a video-display system for S-IOO computers. The display can be programmed for up to forty-eight 80-character lines featuring upper- and lowercase letters with true descenders. The VBS features user-programmable fonts, low intensity, reverse and inverted video, and added print functions such as underscore, strike-through, thin line, or dot graphics. While the VB3 is memory mapped, it occupies memoryaddress space only when activated.

Software for the \/B3 includes a CP/M-compatible driver routine and a terminal-simulator routine. Software controller timing, top and bottom margins, horizontal position, one level of gray, blinking and blank-out character and cursor features are offered. The VB3 video board costs S654.

For further information, contact SSM IVIicrocomputer Products Inc. 2190 Paragon Dr, San Jose

CA 95 131, (408) 946-7400.circle 522 on Inquiry card.

HP-83 from Hewlett-Packard

The HP-83 microcomputer is designed for business and technical professionals. The HP-83 is identical to Hewlett-Packard's HP-85 except that it does not have a built-in tape-cartridge drive and thermal printer. The HP-83 has a high-resolution video display, keyboard, enhanced BASIC, and graphics capabilities. Floppy-disk drives and printers can be interfaced to the unit. A data-base system, graphics software, a communications program, and a graphics digitizing tablet are some of the software and peripheral packages devel

oped for the machine. The HP-83 has a list price of S2250. For more information, contact Inquiries Manager, Hewlett-Packard Company, 1507 Page Mill Rd, Palo Alto CA 94304, (415) 857-1501.

Circle 523 on Inquiry card.

Where Do New Products Items Come From?

The information printed in the new produas pages of BYTE is obtained from "new product" or "press release" copy sent by the promoters of new products. If in our judgment the information might be of interest to the personal computing experimenters and homebrewers who read BYTE, we print it in some form. We openly solicit releases and photos from manufaaurers and suppliers to this marketplace. The information is printed more or less as a first-in first-out queue, subjea to occasional priority modifications. While we would not knowingly print untrue or inaccurate data, or data from unreliable companies, our capacity to evaluate the products and companies appearing in the "What's New?" feature is necessarily limited. We therefore cannot be responsible for product quality or company performance.

470 May 1981 © BYTE Publications Inc

WE WILL NOT BE UNDERiSOLD

DISK DRIVES

FOR TRS-80* Model I

CCMOOTEAC 5y4", 40 Track (102K) $314

CCI-100MPI 5y4",40Track(102K) $319

GCI-280 5y4'^80Track(204K) $429

ADD ON DRIVES FOR ZENITH Z-89 CCI-189 5y4", 40 Track (102K) $394

CCI-289 5y4",80Track(204K) $499

Z-87 Dual 5 y4" system $995

External card edge and power supply Included. 90 day warranty/one year on power supply.

RAW DRIVES 8"SHUGART801R $425 5y4"MPI,TEACorTANDOM SCALL POWER SUPPLIES $CALL

MORROW DESIGNS/THINKER TOYS™

DISCUS 2D 1 DRIVE $ 938 2 DRIVE $1635

DISCUS 2 + 2 1 DRIVE $1259 2 DRIVE $2245

DISCUS Hard Disk M26 $3990 M10 $2999

DEI CARTRIDGE TAPE BACK-UP

For your hard disk. With either S-100 control card or piggy back board for single board Z-80 computers.

DISKETTES — Box of 10 with plastic iibrary case

5y4'' Scotcli $35 Maxeil $40 BASF/Vettoatim

8" Scotch $50 Maxell $55 BASF/VerfoatIm

PLASTIC CASE-Holds 50 5y4" diskettes

SCOTCH HEAD CLEANING DISKETTE

FLOPPY SAVER $11.95 RINGS

PRINTERS

$2995

$27.95 $36.00 $19.00 $25.00 $6.95

COMPLETE SYSTEMS

ARCHIVES 64K,2 Drives, 77Track

ALTOS ACS8000 Series

TRS-80* II-64K $3499

TRS-80* Expansion Interface

ZENITH 48K, alMn-one computer

ZENITH Z-19

TELEVIDEO 920C $ 748

IBM 3101 Display Terminal

ATARI 400 $ 479

MATTEL INTELLIVISION APPLE PERIPHERALS

MONITORS

APF 9"B&WTVM-10 BELL&

HOWELL 9"B&WBHD911

LEEDEX 12"B&W $129

SANYO 9"B&WVM4509

SANYO 12" B&W DM5012

SANYO 12" Green Screen DM5112

SANYO 13" Color DMG6013

ZENITH 13" Color

TELECOMMUNICATIONS

LIVERMORE STAR MODEM 2 year guarantee UNIVERSAL DATA SYSTEMS UDS-103 D-CAT HARD WIRED DIRECT MODEM AUTO-CAT Auto Answer, Direct Connect Modem D.C. HAYES MICRO-MODEM

1-16K

950

800

$5495 $CALL $ 899 $ 299 $2200 $ 735 $1049 $1189 $ 795 $ 229 $CALL

$120

13" Color

$220 $389 $155 $226 $238 $416 $349

$125 $179 $189 $229 $329

NEC Spinwriter

Letter Quality High Speed Printer

R.O.

R.O. with tractor feed KSRwith tractor feed

C.ITOH Starwriter $1695 Starwrlterll EPSON MX-80 $479 MmO

PAPER TIGER IDS 445 IDS 460 IDS 560 ANADEX OKIDATA MIcrollne 80 Microline 80 MIcrollne 82 Microline 83 CENTRONICS 730 TI-810

TRS-80* software, compressed print & vert, form control

Graphics &2K buffer Graphics & 2k buffer Graphics DP-8000 $849

Friction & pin feed

Friction, and pin & tractor feed

Friction & pin feed feed

120 cps, uses up to 15" paper

$ 595 737 $ 749

DP-9500/01

779

$2395 $2595 $2895

$1895 $ 399

$ 699 $1050 $1450 $1345

$ 420 $ 520 $ 620 $ 849 $ 969

$1865

$30

16K RAM KITS 2 tor $56

200 ns for TRS-80*, Apple II, (specify): Jumpers $2.50

S-100 CALIFORNIA COMPUTER SYSTEMS

MAINFRAME Z80 CPU

MOTHER BOARD

16K STATIC RAM, 200ns

32K STATIC RAM, 200ns

64K DYNAMIC RAM

FLOPPY DISC CONTROLLER

EXTENDER BOARD

2P-I-28 I/O

Model 2200A Model 2810 Model 2501 Model 2116C Model 2032C Model 2065C Model 2422A Model 2520K Model 2718A

$349 $269 $106 $309

$359 $ 52 $309

APPLE ACCESSORIES AND SOFTWARE

VISICALC $120.00 DB MASTER $159.00 Z-80 SOFTCARD $269.00 VIDEX BOARD g^^^j^g $259.00

$169.00

16K CARD APPLE JOYSTICK SUPERMOD CCS CARDS

GALAXIAN SPACE ALBUM ASTEROIDS FLIGHT SIMULATOR WIZARD & PRINCESS SARGON 2 HI-RES FOOTBALL MYSTERY HOUSE

$ 49.00 $ 29.00 $CALL

$ 22.95

$ 35.00

$ 17.95

$ 29.00

$ 28.00

$ 29.00

$ 35.00

$ 21.00

For fast delivery, send certified checks, money orders or call to arrange direct bank wire transfers. Personal or company checks require two

to three weeks to clear. All prices are mail order only and are subject to change without notice. Call for shipping charges.

DEALER (NATIONAL/INTERNATIONAL) INQUIRIES INVITED Send ffor FREE CatalogUG

The CPU SHOP

TO ORDER CALL TOLL FREE 1-800-343-6522

TWX: 710-348-1796 Massachusetts Residents call 617/242-3361

5 Dexter Row, Dept. B05M Charlestown, Massachusetts 02129 Hours 10AM-6PM (EST) Mon.-Fri. (Sat. till Circle 104 on inquiry card.

5)

Technical Information call 617/242-3361 Massachusetts Residents add 5% Sales Tax Tandy Corporation Trademark/®Digital Research

American Electronics

Computers For Business, Learning and Entertainment

INCORPORATED

Radio /haok

AUTHORIZED SALES CENTER

For More Information Call

TOLL FREE ORDER NUMBER

800-531-7466 Texas & Principal NUMBER 512-581-2765 Telex Number 767339 Dept. B, 1117 Conway Mission, Texas 78572

CALIFORNIA COMPUTER SYSTEMS

32K RAM BOARD A&T.

450 MSEC $579.95, 200 MSEC $629.95

16K RAM A&T.

450 NSEC $255.95, 200 NSEC $285.95

64K DYNAMIC A&T.

200 NSEC $548.95

Z80 PROCESSOR A&T $259.00

DISC CONTROLLER .$339.95

APPLE IEEE INSTRUMENTATION INTERFACE KIT 7490. A&T $275.00

ARITHMETIC PROCESSOR FOR APPLE 7811 A. A & T .$342.80

APPLE ASYNCHRONOUS SERIAL INTERFACE 771 OA. A & T $137.10

APPLE SYNCHRONOUS SERIAL INTERFACE

7712A. A&T $153.95

ALL OTHER CCS PRODUCTS AVAILABLE

PB-1 2708 & 2716 Programming Board with provisions for 4K or 8K EPROM. No external supplies required. Textool sockets. Kit $143.00

CB-1A 8080 Processor Board. 2K of PROM 256 BYTE RAM power on/rest Vector Jump Parallel port with status. Kit ....$146.00 PCBD $31.95

VB-3 80x24 VIDEO BOARD. Graphics included. 4IV1HZ. Kit $379.95

10-4 Two serial I/O ports with full handshaking 20/60 ma current loop: Two parallel I/O ports. Kit $168.00 PCBD $31.95

VB-IC 64 x 16 video board, upper lower case Greek composite and parallel video with software, S-100. Kit $143.00

CB-2 Z80 CPU BOARD. Kit $199.95

AID APPLE SERIAL/PARALLEL Kit $144.95

ALL OTHER SSM PRODUCTS AVAILABLE

1V777C

inc. WAMECO INC.

MEM-3 32K STATIC RAM 2114 24 bit

addressing $36.95

FDC-1 FLOPPY CONTROLLER BOARD will drive shugart, pertek, ramie 5" & 8" drives up to 8 drives, on board PROM with power boot up, will operate

with CRM™ (not included). PCBD $43.95

FPB-1 Front Panel. IMSAI size, hex displays. Byte, or instruction single step. PCBD $48.50

QM-12 MOTHER BOARD, 13 slot, terminated, S-100

board only $39.95

CPU-1 8080A Processor board S-100 with 8 level

vector interrupt. PCBD $28.95

RTC-1 Realtime clock board. Two independent interrupts. Software programmable. PCBD...... $25.95

EPM-2 2708/2716 16K/32K EPROM CARD.

PCBD $28.95

QM-9 MOTHER BOARD. Short Version of QM-12.

9 Slots. PCBD _ $33.95

MEM-1 8Kx8 RAM 2102.

Buffered PCBD $31.95

PTB-1 POWER SUPPLY AND TERMINATOR BOARD.

PCBD $28.95

IOB-1 SERIAL AND PARALLEL INTERFACE.

2 parallel, one serial and cassette.

PCBD $28.95

2708 $7.50 2114L 450 NSEC $4.99

2716 $25.95 2114L 200 NSEC $5.99

(415) 728-9121 P.O. Box 955 • El Granada, OA 94018

Please send for 10, Xistor and Computer parts list

MAY SPECIAL SALE ON PREPAID ORDERS

(Ctiarge cards not included on this offer)

WAMECO CPU-2. PCBD $29.95

Z80 PROCESSOR WITH MIKOS

PARTS $119.95

WAMECO PCBD

IOB-1, CPU-1 $24.95 EA.

PTB-1, RTC-1 $22.95 EA.

MIKOS PARTS ASSORTMENT WITH WAMECO AND CYBERCOM PCBDS

MEM-3 less RAM _ $ 95.95

Vt/ith 2114L-4 $350.00

V(/ith 2114L-2 $390.00

CPU-1 with MIKOS »2 8080A CPU $99.95

QM-12 with MIKOS #4 13 slot mother

board $110.95

RTC-1 with MIKOS "5 real time clock $65.95

EPM-2 with MIKOS "11 16-32K EPROMS

less EPROMS $65.95

QM-9 with MIKOS »12 9 slot mother

board $99.95

FPB-1 with MIKOS »14 all parts

for front panel $144.95

MIkOS PARTS ASSORTMENTS ARE ALL FACTORY MARKED PARTS. KITS INCLUDE ALL PARTS LISTED AS REQUIRED FOR THE COMPLETE KIT LESS PARTS LISTED. ALL SOCKETS INCLUDED.

LARGE SELECTION OF LS TTL AVAILABLE

PURCHASE S50.00 WORTH OF LS TTL AND GET 10%CREDITTOWARD ADDITIONAL PURCHASES. PREPAID ORDERS ONLY.

VISA or MASTERCHARGE. Send account numtier. interbank num. ber, expiration date and sign your order. Approx. postage will be added. Check or money order will be sent post paid in li.S. If you are not' a regular customer, please use charge, cashier's check or postal money order. Otherwise there will be a twoweek delay for checks to clear. Calif, residents add 6% tax. Money back 30-day guarantee. We cannot accept returned iC's tliat iiave been soldered to. Prices subject to change without notice- $10 minimum order. |1.50 service charge on orders less than $10.00.

Circle 265 on Inquiry card.

THE STAR MODEM

From Livermore Data Systems

RS232 MODEM

SALE

$135

IEEE 488 MODEM

SALE

$245

RS232 coin

$170

IEEE 488 CCITT

$280

STAR Modem is the price peitormance leader with a full

2 YEAR FACTORY WARRANTY.

WE CARRY THE BLJVCK APPLE

EBS Business System for PET/CBM

Extrernely comprehensive package for small business. Fully integrated inventory and accounts receivable system including invoices, packing slips, mail labels, statements, bank deposit slips, and 17 reports.

Pipet^Mite Word Processor $29.95

PET/CBM full featured 60 command system by Michael Riley. Uses either tape or disk and any printer. Includes in-text commands, floating cursor, scrolling, etc.

FLEX-FILE Ditl Bisi for CBM/PET $60

Random file handling system with Report Writer and Mall Ubel Handler. By Michael Riley

KMMM Pascal for PET $75

Subset of standard Pascal with true machine language translator for faster execution. 16K with tape or disk.

EARL for PET (disk file based) $65

Editor, Assembler, Rekjcater, Linker to generate relocatable object code.

fullFORTH+ for PET/CBM $65

A full-featured FORTH with extensions conforming to Forth Interest Group standards. Includes assembler, string processing capabilities, disk virtual memory multiple dimensioned arrays, floating point and integer processing.

MIPLOT Intelligent Plotter by Watanabe Instrutnents (Diglpiot)

SPECIAL $1145

Has all intelligent functions for producing graphs and drawings including 8 vector and 4 character commands Solid and broken lines can be specified Character generator for alpha, numeric, and symbols Characters can be rotated in 4 orientations, and can be 16 sizes Coordinate axes drawn by specifying graduation intenal and number of lepeUtkms, Parallel ASCII interface; 11x17 paper.

SPECIALS

EPSON MX-80 PrIitir EPSON MX-70 Priitir

STARWRITER Daisy Wheel Printer Centronics 737 Printer NEC Spinwriter

XYMEC HI-0 1000 Intelligent Daisy Wheel Leedex Vkleo 100 12" Monitor ZENITH DATA SYSTEMS

Z19 Video Terminal (factory assem.)

Z89 with 48K (factory assem.)

Clll Clil

$1500 790 2500 2150 129

735 2150

SYM-1 209

SYM BAS-1 BASIC or RAE-1/2 Assembler 85

KTM-2/80 Synertek Video Board 349

Seawell Motherboard - 4K RAM 195

Seawall 16K Static RAM - KIM, SYM, AIM 320

8502 6502A 6520 PIA

6522 VIA

6532

7.45

8.40 5.15 6.45 790

2114-1^00 ns RAM 2716EPROM(5volt) TMS 2532 EPROM 4116-200 It RAM S-100 Wire Wrap

10/6.95 50/6.55 100/6.15

10/7.95 50/7.35 100/6.90 10/4.90 50/4.45 100/4.15 10/6.10 50/5.75 100/5.45 10/7.40 50/700 100/6.60 3.75 20/3.50 100/3.25 9.90 5/9.45 1 0/8.90 23.50 I lir 20.00 2.65

CASSEHES - AGFA PE-611 PREiVliUtH

High output, low noise, 5 screw housing, labels. C-10 10/5.65 50/25.00 100/48.00

C-30 10/7.30 50/34.00 100/66.00

All other lengths available. Write for price list

FREE

$1795

235

1795

235

795

75

995

190

1295

205

1295

20S

795

100

95

12

395

50

CALL

4 PART HARMONY MUSiC SYSTEM for PET

Allows you to easily enter, display, edit, and play 4 part hannony music. Includes whole notes thai 64ths (with dotted and triplets), tempo change, key signature, transpose, etc The KI.-4 M unit Includes D to A converter and amplifier (add your own speaker). KL-4M Muite BiH with VMM Prg|nm {59.90

CBM-PET SPECIALS

>V, Up to $235 FREE

mrchiidin Willi pNrciiaii If no If fiinlio CBM-Pr HmhI

8032 32K-80 column CRT 8050 Dual Disk Drive -1 megabyte

8N Full size graphics keyboard 16K Business or Graphic Keyboard 32K Business or Graphic Keyboard 2040/4040 Dual Disk Drive - 340K 2022 Tractor Feed Printer C2N External Cassette Deck CBM Voice Synthesizer Used CBM/PET Computers

WRITE FOR SYSTEM PRICES

***EDUCATiONAL DISCOUNTS*** Biy 2 PET/CBM CMpitm, nuin 1 FREE

WordPro 3-f- 32K, disk, printer 250

WordPro 4-1- 8032, disk, printer 385

OZZ Data Base System for CBM 8032 335

VISICALC for PET, ATARI 170

BPI General Ledger, A/P, A/R for PET/CBM 270

EPROM PrHniMr lir PET 72.00

Programmers Toolkit - PET ROM Utilities 34.90

2 Meter IEEE to IEEE Cable 43.00

PET Spacemaker Switch 24.90

Dust Cover for PET 6.90

IEEE-Parallel Printer Interface for PET 110.00

IEEE-RS232 Printer interface for PET 120.00

The PET Revealed 17.00

Ubrary of PET Subroutines 17.00

DISK

SPECIALS

SCOTCH (3M) S'A" 10/2,

SCOTCH (3M) 8" 10/2.

Vert)atlm5W' 1C/2.

(add 1,00 for 5y4"Vert)atim

Verbatim 8" Dbl Dens 10/3

BASF 5y4" soft 10/2,

BASF 8" soft 10/2,

Maxell Disks In stock

Diskette Storage Pages Disk Library Cases 8"

:,90 50/2.80 100/2.70 ,95 50/2.85 100/2.75 .45 50/2.40 100/2.35 plastic storage box) 45 50/3.35 100/3.25 ,60 20/2.50 100/2.40 65 20/2.55 100/2.45

write for prices

10 for 3.95 - 2.85 5"-2.15

AATARI 800 $777 All Atari Modules 20% OFF

ATARI EDUCATIONAL PLAN Writi fir Mlli

A P Products 15% OFF APHobby-Blox 15% OFF

Sourct Hookup over 1000 programs/services 88

ALL BOOK and SOFTWARE PRICES DISCOUHTED

The 8086 Book (Osborne) 14.00

Z8000 Assembly Language Programming 16.90

PET Personal Computer Guide (Osborne) 12.75

PET and the IEEE-488 Bus (Osborne) 13.60

6502 Assembly Language (Osborne) 14.45

Programming the 6502 (Zaks) 10.45

6502 Appllcatkxis Book (Zaks) 10.45

6502 Software Cookbook (Sceibi) 9.45

CP/M Handbook (w/MP/M) Zaks 11.85

Practical BASIC Programs (Osborne) 13.60

Some Common BASIC Programs (Osborne) 12.75

115 E. Stump Road Montgomeryville, PA 18936

215-699-5826 A B Computers

WRITE FOR CATALOG.

AddSl 25 pet order lor shipping We pay balance ol UPS surlacectiarges on all prepaid orders Prices listed are on cash Oiscounl basis Regular prices slightly highec

Circle 1 on inquiry card.

BYTE I^y 1981 473

Circle 439 on inquiry card.

Yes! We supply IMSAI compatible products...

NOTE: "Original" IMSAI parts were purchased at the closing business sale of IMSAI Manufacturing Corp. WW Components also distributes S-100 buss IMSAI compatible parts and boards. As supplies of "original" parts are exhausted, WW reserves the right to supply equivalent compatible parts not made by IMSAI. All items listed as "Assembled & Tested" have been assembled by WW Components and carry a 1 year warranty.

1-8080 S-100 ENCLOSURE Sheet Metal Kit

MPU-B SBC 8085 CPU

PS-28D Power Supply Parts Kit:

1-8015 Complete System w/MPU'B

CP/iVI® 2.2 for IMSAI

THE ORIGINAL IMSAI: Mainframe vt/ith blue cover, cardguides and hardware spaced for PS-28D Power Supply, up to 22 slot motherboard. Kit of all metal parts and hardware w/docs $115.00 Thinker Toys WunderBuss20 for above w/o conn. $79.00

Complete 8085 based CPU including: serial RS-232 port, parallel I/O port 3 MHz operation, 256 bytes memory, ROM monitor, 3 timers, and more.

Assembled & Tested $250.00 Mounts in tlie 1-8080 enclosure, supplies +8V @ 28A, +1- 16V @ 3A, kit includes board, transformer, documentation, and all components.

KIT $95.50

The complete 8085 system, includes MPU-B, RAM III, 10 slot terminated motherboard, PS'28D, and jump start front panel. A complete 64K system!

Assembled & Tested $1250.00

NOW AVAILABLE - CP/M for the IMSAI floppy disk system. Version 2.2 is available for the DIO-C 8" controller. Others on request. Docs. incl.

8" Diskette & Manuals $175.00

Ask about documentation, repair service, firmware and software fpr your system.

TERMS: (1) PREPAID Send check or M.O. for merchandise amount only - we pay the shipping in USA only. (2) UPS COD or bankcard orders by phone or mail - shipping charges added. California Residents add 6.5% Sales Tax.

HICKOK DIGITAL MULTIMETERS

Model 1X304 7950

DMM +Vari-Pitch +Logi-Trax

MX-333

Model

'210 LX3IB

VIIZ Tech DMM SVzDigit LCD Readout

Model WD 747 $yg95

Beckman DIGITAL MULTIMETERS

'^^^ Model TECH 300 *1 09^^ Model TECH 310 '1 40"" Model TECH 330

$19995

DIGITAL MULTIMETERS

Model 462 Model 463

260 Meter

Model 260-7

$QC Complete with nickei^'J' cadmium batteries, AC charger/adapter, test

Magnifier Lamp

Precision ground dnd poiisned ' magnification lens

Model LFM-1A

Casio Calculator Calendar Watch

Model C-80

$4250

fff^PRECISIOni

15 MHz Minlscope

Rise time 11.7 nS or-pjless • Built-in sigrial ■' delay line • Flat

response L* ® •

Dual Trace fi!;lSI3"9'"8

5 "30 MHz triggered Scope

Model 1479A

Digital

Pulsar Probe Model dp-ioo 50 MHz

Pulsar Probe Model dp-so

DMM

3y2-D[git 0.1% Digital ^ Capacitance Meter

^ft Model 3001

Function Generator

Model 2001 $15795

Proto Boards Logic Monitor

-Tt=!%^ • Automatically Model VC»y%. tlisplays static and ^ 1

PB-104

Fully assembled

«5995

dynamic logic < Works with DTL, Model LM-1 HTL.TTL, and

Touchiest 20 Multimeter

15 MHz Dual - Trace Triggered

EKHH MIniscope

\\ft»:» <Si<l^-Uj!// Model MS-215

30 MHz Dual Trace Triggered

Minlscope Modet Ms-230

PK40D ~ — — — S7A99

4 PC standard Starter Kit»0ne(1) Standard Command f H Console ■ Two (2) Lamp Modules ■ One (1) Appliance Module

PK500 5 Pc Ultrasonic Starter Kit'One (1) Deluxe *Ar\QR UllrasDnic Coninijiul Console ■ One (1) Hand Held Remote *yH^''

Umi ■ Two [91 Unip MoOijies" One (I) Appliance Uni|

LM501 Lamp MuQjIe S13.95 AM601 A[iplianci: Mopjle S13.95 WSTOlWall Swiir.h Machile S13.95 WS711 Wall Swittli MoiJuli;

Witt) independent On-Olf

pQwer buttons S1S.95

The Timer $5995

Miniature High Fidelity 3-Way Stereo Speakers

Sensory Chess

Chess Challenger 7 Challenger'110.

$7095 Voice Sensory

1^ m\ Challenger

$24995

WAHL

Cordless Soldering Iron $2995

Thenmtd-S/iat

Circuit Tester

Finds faulty components || quickly and easily

»2995„„,„

5800

MURAPHONE Cordless Telephone System

Weller*

WTCPN Controlled Output Soldering Station

Model WTCPN $5750

Service Master Tool Kit $4995

Model go-SM

Soldering Station

24995

In-Dash Car Stereos

B-Track AM/FM $RO50,

Model JCS 420 [

Cassette AM/FM $S750^

Model JCS 505 *"

Digital Cassette AM/FM $89^^

with Clock Model JCS 607

Graphic Equalizer

Model iSE 5000 $3995

6x9 3-Way $1295 ea •■■♦m Speakers ■ 20 oz, magnet

Madel BP2000-6g TRD

855 Conklin St. Farmingdale. N.Y. 11735

■ b"!*/ I ADD FDH SHIPPING AND IHSUHAMCE

■ BBnKAmericara i ^^, jsD 00 -S 3.50 -VISA "COD I IZ51.IKI1D .600.00 5.M

501.0010 750.00 T.50

751.00 to 1000.00 10.00

ovtr 1000.00 12.50

■ Money Order

■ Check

N.Y. State residents add

appropriate sales tax

I COD'S mn

474 BYTE May 1981

fSE^E^(800)645-9518

in N.Y. state call (516) 752-0050 mihhI

Circle 163 on inquiry card,

MICROPROCESSOR SUPPORT ICS

WE GUARANTEE FACTORY PRIME PARTS

We are going to become the largest supplier of prime microprocessor support I.C.'S. We guarantee that our I.C.'S are purchased from manufacturer authorized distributors. This is the only way to deliver prime parts at the lowest possible prices. Our committment is to offer the best price and the fastest delivery to our customer. We give many thanks to our valued customers who have helped us grow.

NEC 16Kx1 DYNAMIC RAM 200 N.S. These are prime 4116's from one of the best MOS RAM manufacturers in the world.

4116 200ns 8 for $25.00 32 for 96.00

Only prepaid orders on this special.

8080A

CPU

4.95

2708 EPROM 1Kx8 4.95

NEC 1Kx4 STATIC RAM 250 N.S.

8085A

CPU

8.95

2716 EPROM 2Kx8 8.95

These

are prime low power

Static ram's

NEC

8086

CPU

99.95

2732 EPROM 4Kx8 21.00

for the finest in

MOS MEMORY.

8088

CPU

44.95

4118 STATIC 1Kx8 15.00

2114L

250ns

Z-80

CPU

10.50

4164 200ns

64Kx1 Call

8 for $25.00

32 for $96.00

Z-80A

CPU

12.95

Z80B CPU

21.00

Only prepaid orders on this special.

Z80-P10

7.75

8289 49.95

4050

.69

4531

.99

74C925

6.95

74LSI 07

.45

74LS244

1.95

Z80A-P10

9.75

4000

.35

4051

1.10

4532

1.25

74LSO0

.35

74 LSI 09

.45

74LS245

4.95

Z80-CTC

7.75

4001

.35

4052

1.10

4539

.99

74LS01

.28

74LS112

.49

74LS247

1.10

Z80ACTC

9.75

4002

.35

4053

1.10

4543

1.99

74LS02

.28

74 LSI 22

.55

74LS248

1.10

Z80-DMA

22.25

4006

1.39

4055

3.95

4553

3.50

74LS03

.28

74 LSI 23

1.19

74LS249

1.69

Z80A-DMA 27.75

4007

.29

4056

2.95

4555

.75

74LS04

.39

74 LSI 25

1.35

74LS251

1.79

Z80-S10/0

24.95

4008

1.39

4059

9.95

4556

.75

74LS05

.28

74 LSI 26

.89

74LS253

.98

Z80A-S10/0 29.95

4009

.49

4060

1.39

4581

1.99

74LS08

.39

74 LSI 32

.79

74LS257

.98

Z80-S10/1

24.95

4010

.49

4066

.75

4582

1.01

74LS09

.39

74LS136

.59

74LS258

.98

Z80A-S10/1 29.95

4011

.35

4068

.35

4584

.55

74 LSI 0

.28

74 LSI 38

.89

74LS259

2.95

Z80-S10/2

24.95

4012

.29

4069

.35

4585

.99

74 LS11

.39

74 LSI 39

.89

74LS260

.69

Z80A-S10/2 29.95

4013

.49

4070

.49

4702

9.95

74 LSI 2

.39

74 LSI 45

1.25

74LS261

2.49

3205

3.45

4014

1.39

4071

.35

74C00

.39

, 74LS13

.47

74 LSI 48

1.49

74LS266

.59

3242

10.00

4015

1.15

4072

.35

74C02

.39

74LS14

1.25

74 LSI 51

.79

74LS273

1.75

8155

11.25

4016

.59

4073

.35

74C04

.39

74LS15

.39

74LS153

.79

74LS275

4.40

8185

29.95

4017

1.19

4075

.35

74C08

.49

74LS20

.26

74LSI 55

1.19

74LS279

.59

8185-2

39.95

4018

.99

4076

1.29

74C10

.49

74LS21

.38

74 LSI 56

.99

74LS283

1.10

8202

45.00

4019

.49

4078

.35

74C14

1.65

74LS22

.38

74 LSI 5/

.99

74LS290

1.29

8205

3.45

4020

1.19

4081

.35

74C20

.39

74LS26

.39

74 LSI 58

.75

74LS293

1.95

8212

2.00

4021

1.19

4082

.35

74C30

.39

74LS27

.39

74 LSI 60

.98

74LS295

1.10

8214

3.95

4022

1.15

4085

1.95

74C32

.99

74LS28

.39

74LS161

1.15

74LS298

1.29

8216

1.85

4023

.38

4086

.79

74C42

1.85

74 LS30

.26

74 LSI 62

.98

74LS324

1.75

8224

2.65

4024

.79

4093

.99

74C48

2.39

74LS32

.39

74 LSI 63

.98

74LS347

1.95

8226

1.85

4025

.38

4099

2.25

74C73

.85

74LS37

.79

74 LSI 64

1.19

74LS348

1.95

8228

5.00

4026

2.50

4104

1.99

74C74

.85

74LS38

.39

74 LSI 65

.89

74LS352

1.65

8238

5.45

4027

.65

4501

.39

74C85

2.49

74LS42

.79

74 LSI 66

2.49

74LS353

1.65

8243

4.65

4028

.85

4502

1.65

74C89

4.95

74LS47

.79

74LS1 70

1.99

74LS363

1.49

8251A

5.55

4029

1.29

4503

.69

74C90

1.85

74LS48

.79

74LS1 73

.89

74LS365

.99

8253

9.85

4030

.45

4505

8.95

74C93

1.85

74LS51

.26

74LS1 74

.99

74LS366

.99

8255A

5.40

4031

3.25

4506

.75

74C95

1.85

74LS54

.35

74LS175

.99

74LS367

.73

8255A-5

5.40

4032

2.15

4507

.95

74C107

1.19

74LS55

.35

74 LSI 81

2.20

74 LS368

.73

8257

9.25

4033

2.15

4508

3.95

74C151

2.49

74LS73

.45

74 LSI 90

1.15

74LS373

2.75

8257-5

9.25

4034

3.25

4510

1.39

74C154

3.50

74LS74

.59

74 LSI 91

1.15

74LS374

2.75

8259A

7.30

4035

.95

4511

1.39

74C157

2.10

74LS75

.68

74 LSI 92

.98

74LS375

.69

8271

60.00

4037

1.95

4512

1.39

74C160

2.39

74LS76

.45

74 LSI 93

.98

74LS377

1.95

8275

32.95

4040

1.29

4514

3.95

74C161

2.30

74LS78

.65

74 LSI 94

1.15

74LS385

1.95

8279

10.80

4041

1.25

4515

3.95

74163

2.39

74LS83

.99

74LS195

.95

74LS386

.65

8279-5

10.80

4042

.95

4516

1.69

74164

2.39

74LS85

1.19

74 LSI 96

.89

74LS390

1.95

8282

6.70

4043

.85

4519

.99

74173

2.59

74LS86

.45

74LSI 97

.89

74LS393

1.95

8283

6.70

4044

.85

4520

1.39

741 74

2.75

74LS90

.75

74LS221

1.49

74LS395

1.70

8284

5.85

4046

1.75

4522

.99

74C175

2.75

74LS92

.75

74LS240

1.95

74LS399

2.95

8286

6.70

4047

1.25

4526

1.15

74C192

2.39

74LS93

.75

74LS241

1.90

74LS424

2.95

8287

6.70

4048

.99

4527

1.75

74C193

2.39

74LS95

.88

74LS242

1.95

74LS668

1.75

8288

26.40

4049

.69

4528

.99

74C195

2.39

74LS96

.98

74LS243

1.95

74LS670

2.29

MAIL ORDERS SHOULD BE SENT TO: P.O. Box 21432 Seattle, Washington 98111 Telephone Orders & Inquiries (206) 453-0792 Minimum Order $10.00 Add $3.00 Shipping

HAHLEY [NGIMURING

RETAIL STORE 1644 116th NORTHEAST BELLEVUE, WASHINGTON 98005

FOR THE FINEST IN MICROPROCESSOR SUPPORT I.C.'S

Circle 174 on inquiry card.

BYTEMqrl981 475

Circle 255 on inquiry card.

DISCOUNTS & DEALER OVERSTOCKS

ALL ITEMS BELOW SOLD AS IS - NO RETURNS / NO REPAIRS 1 CALL FOR AVAILABIUTY: UMITED QUANTITIES

Sell For

List Price

Polymorphic Sjf,i^0mt

SK Assembled

289.00

385.00

A.I. Cybernetic! Speechboard

260.00

380.00

BK Memory Board

225.00

300.00

Anadex 40 Column Frintei

641.00

855.00

Poly KBD

169.00

225.00

Baie 2 8K Memory Board Asaembled

211.00

282.00

8813

2880.00

3250.00

Commodora 2001-8 8K PET

550.00

795.00

System 0

378.00

525.00

Craig M-lOO Tranilater

122.00

199.95

aS'System 2

529.00

735,00

Dajen CaiMtta Interface

88.00

120.00

System 12 Kit

846.00

1128.00

Dynabyte Nakad Tamiiiial

24S.00

350.00

Syalsm6

1134.00

1575.00

Digital Systemf Dual 8" Sisgte Density

2293.00

2732.00

Video Card

210.00

280.00

Dulronicfi Poly Z-80 Upgrade Kit

123.00

169.95

FroceBBor Tech

DuIioniCB Imssi Z-60 Upgrade Kit

116.00

159.95

Cuts BD Assembled

139.00

199.00

Eclectic Corp. Superchip for Apple II

75.00

95.00

8K Dynamic Ram

175.00

250.00

Fidelity Electronics Ltd.

16K Dynamic Ram

300.00

429.00

Level 1 Chesa Challenger

120.00

75.00

64K Dynamic Ram

878.00

1350.00

Level 4 Checker Challenger

100.00

IIS.OO

Extended Basic Casaatta

21.00

45.00

Level 2 Checker Challenger

40.00

40.00

SOL 20 W/0 Memory

1270.00

1895.00

George Rink Inc. Pet Keyboard

176.00

250.00

System II Kit

1262.00

1905.00

Imsai CPU Board

125.00

175.00

Panasonic Monitor

143.00

210.00

IcDto Micro Peripherals 5" Disk Drive

821.00

1095.00

SD Sales 32K Dynamic Ram Board Kit

332.00

475.00

Intertec Data Intertube Terminal

595.00

874.00

Solid State Music 16K Static Ram Board Kit

300.00

Kant Moore 8K RAM 4S0MS

148.00

197.80

Southwest Technical (SWTFC)

Kent Moore Alpha Display Module

80.25

107.00

MF-68 Dual 5" Floppy

796.00

995.00

Mountain Hardware

Graphics Teminal

79.00

98.50

AC Control Apple

132.00

189.00

Technical Design Labs (TDL-Xitan)

AC Remote

9S.00

149.00

I/O board - SMB-U

257.00

395.00

S-100 AC Control Kit

104.00

149.00

32L Series K Memory Board

559.00

799.00

AC Remote Kit

67.00

99.00

Fortran IV Ser.37

279.00

349.00

AC Control- Apple Kit

104.00

145.00

Fortran IV Sor.41

279.00

Micromation Dual Memoiez 8" disk drive

1467.00

1990.00

Xilan Alpha 1.5

823.00

1138.00

Micromation Dual Density distc controllar Card

310.00

500.00

Xitan Alpha 1

576.00

769.00

MS Corp. Apple FR-40 Interlace

87.00

87.00

Xitan Alpha 3

854.00

1181.00

National Mulliplai Digital Canalta Raoorder

ISO.OO

200.00

Xitan Alpha 1.5

571.00

868.00

Novation 1200 Baud Modem (4Z02T)

274.00

375.00

Video Board

277.00

369.00

Radio Shack TRS-80 Disk Drive

399.00

499.00

Teohnico Super Starter Assembled

293.00

300.00

TRS-80 16K Computer

479.00

599.00

Teohnico Super Starter Kit

199.00

299.00

TRS-80 Expansion Interface

239.00

299.00

Trace Elec. 32K RAM Board Assam

599.00

699.00

NEW EQUIPMENT

CALL FOR

OUR LOW PRICES

FOR THE FOLLOWING

MANUFACTURERS:

APPLE ATARI

CROMEMCO VECTOR GRAPHIC

MicroCompEquip

PO BOX 195

CROWNSVILLE, MD 21032

VISA / MC / CHECK

PHONE ORDERS: (301) 261-1859

64KBYTE EXPANDABLE RAM

DYNAMIC RAM WITH ON BOARDTRANSPARENT REFRESH GUARANTEED TO OPERATE IN NORTHSTAR, CROMEMCO, VECTOR GRAPHICS, SOL, AND OTHER 8080 OR Z-80 BASED SlOO SYSTEMS ♦4MHZ Z-80 WITH NO WAITSTATES,

* SELECTABLE AND DESELECTABLE IN 4K INCREMENTS ON 4K ADDRESS BOUNDARIES,

* LOW POWER-8 WATTS MAXIMUM.

* 200NSEC4116RAMS.

* FULL DOCUMENTATION.

* ASSEMBLED AND TESTED BOARDS ARE GUARANTEED FOR ONE YEAR AND PURCHASE PRICE IS FULLY REFUNDABLE IF BOARD IS RETURNED UNDAMAGED WITHIN 14 DAYS.

ASSEMBLED/ TESTED

64KRAM S595.00

48KRAM 1529.00

32KRAM 1459.00

16KRAM S389.00

★ VII SOLID FRONT PANa .. $239.06

* W CUTOUTS FOR 2 MINI-FLOPPIES... $239.00

♦ 30 AMP POWER SUPPLY $119.00

* 8 SLOT MOTHERBOARD $149.00

: 19 SLOT MOTHERBOARD S199.00

I i

1SK MEMORY EXPANSION KIT

ONLY $58 FOR APPLE, TRS-80 KEYBOARD, EXIOY, AND ALL OTHER 16K DYNAMIC SYSTEMS USING MK4116-3 OR EQUIVALENT

DEVICES.

★ 200 NSEC ACCESS, 375 NSEC CYCLE

★ BURNED IN AND FULLY TESTED

★ 1 YR. PARTS REPLACEMENT GUARANTEE

★ QTY; DISCOUNTS AVAILABLE

VISTA V-200 MINI-FLOPPY SYSTEM

★ S100 DOUBLE DENSITY CONTROLLER

★ 204 KBYTE CAPACITY FLOPPY DISK DRIVE WITH CASE & POWER SUPPLY

★ MODIFIED CPM OPERATING SYSTEM WITH EXTENDED BASIC

$695.00

COmPUTER DEVICES

I230 IJU.COUmi flUE. ORflnCE, Cn 92668 (714)633-7280

Calll. residents please add 6% sales Isx. Maslercharge & Visa accepted. Please allow 14 days for checks to clear bank. Phone orders welcome. Shipping charges will be added to all shipments.

32K BYTE MEMORY RELIABLE/COST EFFECTIVE EXPANDABLE RAM FOB 6502 AND 6800 SYSTEM-AIM 65.*KIM*SYM*PET*S44-BUS

* PLUG COMPATIBLE WITH THE AIM-65/SYM EXPANSION CONNECTOR BY USING A RIGHT ANGLE CONNECTOR (SUPPLIED) MOUNTED ON THE BACK OF THE MEMORY

BOARD,

* MEMORY BOARD EDGE CONNECTOR PLUGS INTO THE 6800 S 44 BUS.

* CONNECTS TO PET OR KIM USING AN ADAPTOR CABLE.

* RELIABLE-DYNAMIC RAM WITH ON BOARD INVISIBLE REFRESH-LOOKS LIKE STATIC MEMORY BUT AT LOWER COST AND A FRACTION OF THE POWER REQUIRED FOR STATIC BOARDS,

. USES +5V ONLY, SUPPLIED FROM HOST COMPUTER.

* FULL DOCUMENTATION. ASSEMBLED AND TESTED BOARDS ARE GUARANTEED FOR ONE YEAR AND PURCHASE PRICE IS FULLY REFUNDABLE IF BOARD IS RETURNED UNDAMAGED WITHIN 14 DAYS.

ASSEMBLED WITH 32K RAM...:._ $395 00

S WITH 16K RAM $339,00

TESTED WITHOUT RAM CHIPS $279 00

HARD TO GET PARTS (NO RAM CHIPS)

WITH BOARD AND MANUAL $109,00

BARE BOARD & MANUAL $49,00

96 »

PET INTERFACE KIT-CONNECTS THE 32K RAM BOARD TO A 4K OR 8K PET, CONTAINS: INTERFACE CABLE, BOARD STANDOFFS, POWER SUPPLY MODIFICATION KIT AND COMPLETE INSTRUCTIONS {40.00

U,S, PRICES ONLY

476

BYTE May 1981

DIGITAL RESEARCH COMPUTERS

(214) 271-3538

32K S-100 EPROM CARD NEW!

$74.95

KIT

USES 2716'S

Blank PC Board - $34

ASSEMBLED & TESTED ADD $30

SPECIAL: 2716 EPROM's (450 NS) Are $11.95 EA. With Above Kit.

KIT FEATURES

1 Uses +5V only 2716 (2Kx8) EPROM's.

2 Allows up to 32K of software on line!

3 IEEE S-100 Compatible.

4 Addressable as two independent 16K

blocks

5 CromemcoextendedofNorthstarbank select.

6. On board wait state circuitry if needed.

7. Any or all EPROM locations can be disabled.

8. Double sided PC board, solder-masked, silk-screened.

9. Gold plated contact fingers.

10. Unselected EPROM's automatically powered down for low power.

11. Fully buffered and bypassed.

12. Easy and quick to assemble.

32K SS-50 RAM

^379

00

KIT

For 2MHZ Add $10

Blank PC Board $50

For SWTPC

6800 - 6809 Buss

Support IC's and Caps $1<).95 Complete Socket Set $21.00

Fully Assembled, Tested, Burned In Add $30

At Last! An allordable 32K Static RAM witli lull 6809 Capability.

FEATURES:

1. Uses proven low power 2114 Static RAMS.

2. Supports SS50C-EXTENDED ADDRESSING.

3. All parts and sockets Included.

4. Dip Switcli address select as a 32K block.

5. Extended addressing can be disabled.

6. Works with all existing 6800 SS50 systems.

7. Fully bypassed. PC Board Is double sided, plated thru, with silk screen.

16K STATIC RAM KIT-S 100 BUSS

PRICE CUT!

^199^^iT

16K STATIC RAM SS-50 BUSS

PRICE CUT!

KIT FEATURES-.

1 Addressable as lour separate 4K Blocks, 2, ON BOARD BANK SELECT circuitry (Cromemco Standard') Allows up to 512K on line'

3 Uses 2114 (450NS) 4K Static Rams

4 ON BOARD SELECTABLE WAIT STATES.

5 Double sided PC Board, with solder mask and SUPPORT IC'S & CAPS-$19 95 silk screened layout Gold plated contact fingers

6, All address and data lines fully buffered

7. Kit includes ALL parts and sockets.

8 PHANTOM is jumpered to PIN 67.

9 LOW POWER: under 1.5 amps TYPICAL from the -^B Volt Buss,

10, 3lank PC Board can be populated as any multiple of 4K.

BLANK PC BOARD W/DATA-$33 LOW PROFILE SOCKET SET-$12

ASSEMBLED & TESTED-ADD $35

FOR SWTPC 6800 BUSS!

OUR #1 SELLING RAM BOARD!

KIT FEATURES

' Addressable on 16K Boundaries 2 Uses ?114 Static Ram 3. Fully Bypassed

4 Double sided PC Board Solder mask and silk screened layout

5 Parts and Sockets included

6 Low Powei Under 1 5 Amps Typical

BLANK PC BOARD—$35 COMPLETE SOCKET SET—$12 SUPPORT IC'S AND CAPS—$19.95

ASSEMBLED AND TESTED - $35

STEREO! 100 SOUND COMPUTER BOARD '

COMPLETE KIT! $8495

(WITH DATA MANUAL)

At fast, an S-100 Board that unleashes the lull power of two unbelievable General lnstrumentsAY3-8910 NMOS computer sound IC'S Allows you under total computer control to generate an infinite number of special sound effects for games or any other program. Sounds can be called in BASIC.

ASSEMBLY LANGUAGE etc. KIT FEATURES:

• TWO Gl SOUND COMPUTER ICS . FOUR PARALLEL I'O PORTS ON BOARD

• USES ON BOARD AUDIO AMPS OR YOUR STEREO

• ON BOARD PROTO TYPING AREA,

* ALL SOCKETS, PARTS AND HARDWARE ARE INCLUDED

* PC BOARD IS SOLDERMASKED, SILK SCREENED. WITH GOLD CONTACTS, » EASY, OUICK, AND FUN TO BUILD, WITH FULL INSTRUCTIONS

* USES PROGRAMMED I/O FOR MAXIMUM SYSTEM FLEXIBILITY Both Basic and Assembly Language Programming examples are included

SOFTWARE:

SOL"" is now available! Our Sound Command Language makes writing Sound Etfects programs a SNAPI SCL™ also includes routines for Register-Examine-Modity, Memory-Examine-Modily. and Play-Memory. SCL" is available on OP/M' compatible diskette or 270S or 2716. Diskette $24.95 2708 - $18.95 2716 - $29.95. Diskette includes the source. EPROM'S are ORG at EOOOH.

BLANK PC BOARD W/DATA

$31

4K DYNAMIC RAM BLOWOUT! SAME AS INTEL 2107B! 4K RAMS AT AN UNBELIEVABLE 50<t EACH!!!

Prime, new. National Semi., 1979 date cotded, full spec, parts, N,S #MM5280-5N, Same as INTEL 2107B-4, T.I. TMS4060. NEC uPD411, etc. We bought a HUGE QTY. from a West Coast Distributor at truly DISTRESS PRICES! One of the most popular and reliable RAM's ever made. These parts have been used by almost all Major Computer Main Frame Mfg. the world over! Arranged as 4K x 1,270 NS Access Time, 22 Pin Dip These units DO NOT use multiplexed addressing, thus making REFRESH and other timing very simple. See INTEL MEMORY DESIGN HANDBOOK for full application notes. 1 he NAT. SEMI. MEMORY DATA BOOK is available at most Radio Shacl< Stores. Prime units In original factory tubes!

^yr, #5280-5N 4096 BITS x 1 270 NS ACCESS 8 FOR $4.95 32 FOR $16 °" FACTORY CASE (450 PCS) — $180

Sockets Special: 22 Pin Low Profile (With Purchase of 5280's) 8 FOR $1.

COMPUTER PARTS SPECIALS

74LS175 - .99 8035 Intel Single Chip CPU 6.95

74LS240 - 1.19 SIgnetics 2901 4 Bit Slice - 6.95

74LS241 - 1.19 AMD 2903 4 Bit Super Slice -12.50

74LS244 - 1.19 AMD 29705 Dual Port RAM - 8.95

74LS373 - 1.29 Intel 2716-1 (350 NS) - 12.95

NEW! G.I. COMPUTER SOUND CHIP

AY3-8910 As featured in July. 1979 RYTEi A fantastically powerful Sounij & Music Generator, Perfecl for use with any 8 Bit Microprocessor Contains 3 Tone Channels. Noise Generator, 3 Channels of Amplitude Control 16 bii Envelope Period Control, 2-B Bit Parallel I/O 3 D to A Converters, plus much more' All m one 40 Pin DIP. Super easy interface to the S-IOO or other [■i.c-ses $11.95 PRICE CUT!

SPECIAL OFFER: $14.95 e;5ch Add $3 for 60 page Data Manual.

Digital Research Computers

(OF TEXAS) ' P.O. BOX 401565 • GARLAND. TEXAS 75040 • (214) 271-3538

TERMS: Add $2.00 postage. We pay balance. Orders under $15 add 75« handling. No C.O.D. We accept Visa and MasterCharge. Tex. Res. add 5°b

Tax Foreign orders (except Canada) add 20% P & H. Orders over $50. add BSC lor insurance

"TRADEMARK OF DIGITAL RESEARCH.

WE ARE NOT ASSOCIATED WITH DIGITAL RESEARCH OF CAUFORNIA, THE SUPPLIERS OF CPM SOFTWARE.

■ BYTE May 1981 477

circle 151 on Inquiry card.

CALL TOLL FREE

1-800-2M-4097

Call Toll Free For "Unbelievable"

Low Low Prices On These Lines:

APPLE —ATARI —BASE 2

CENTRONICS COMMODORE —DC HAYES

HAZELTINE —LEEDEX MACROTRONICS — MAXELL

MOUNTAIN HARDWARE NORTH STAR —PANASONIC SANYO — SYNCOM

master charge

gLicirmoiNiiici i^LAy@i§@yiNip

1840 "O" street Lincoln, Nebraska 68508 In Nebraska Call (402) 476-7331

VISA

LOBO Add-On Disk Drive Subsystems

For Apple, TRS-80, S-100 Based Computers

Expansion and enhanced capabilities are key words in achieving full utilization of your computer system. Our complete line of LOBO disk drive subsystems are ttie ideal, cost-effective w/ay to provide the expansion capabilities you need to meet your system growth requirements. All of our subsystems are complete, ttioroughly-tested, 100% burned-in, and feature a 1 year 100% parts/labor warranty.

APPLE

'Double Density Controller

3101 MInitldppy, $399 31011 Minifloppy w/interface card $489

8101CA One SA800 in cabinet w/power. DDC Controller, cable and manual $1449

8202CA Two SA800 in cabinet w/power, DDC Controller, cable and manual $1889

5101CA One SA850 in cabinet w/power, DOC* Controller, cable and manual $1759

5202CA Two SA850 in cabinet w/power, DDC Controller, cable and manual $2364

LCA-22 Double Density Controller only $599

S-100 BASED COIVIPUTERS

MODEL NO. DESCRIPTION

JIOIC SA400 in cabinet w/power $369

82120 Two SA801 in cabinet w/power S^32^

5212C Two SA861 in cabinet w/powoi S! ■

GENERAL

MODEL NO.

8212C

DESCRIPTION

Two SA801 in cabinet w/power $1329

Two SAOSI in cabinet

TRS80

MODEL NO, DESCRIPTION

4101C SA400 in cabinet w/power $369

8101C II One SABOO In cabinet w/power for Mod. II $909

8202C II Two SA800 in cabinet w/power lor Mod. II $1349

LX80 Double-density expansion interface $641

RS232 Dual Serial Port Option $75

VISA'

JR

INVENTORY CO.,

P.O. Box 185, Santa Yne2,Ca., 93460

478 BYTE May 1981

Circle 210 on Inquiry card.

ELECTRONICS

INTEGRATED CIRCUITS

P.O. Box 4430X Santa Clara. CA 95054 Will calls: 2322 Walsh Ave. (408) 988-1640 TWX 910-338-2139 Same day shipmant. Rrst line parts only. Factory tested. Guaranteed money back. Quality IC's and other components at factory prices.

7<0DnL

7400N

7402H

74MM

r409N

74tON

74 HH

7«2N

7Am

7AA2H

am 7mn

7450N 7'174N 7475N

imu

74B9N 1

nm

7492N 7493N 7*m

74 tow I

74107N

74l21tl

74123N

74125N

74145N

741 SON !

7ai51N

7^154>J I

74157N

741S1N

74163N 74174N 74175N 741MN 1

jmzH

74193N 74221N 1 742SeN 1 7436SN 743SSK 74367N

74LI00 TTL

74LS00N

74L502N

74LS04N

74LS05N

74L5DeN

74LS1C1N

74LS13N

7JLSMN 1

7JL520N

74LS23N

74(.S;SN

74LS30N

74LS33N

74LS38N

74LS74N

74LS75N

74LS90N

74LS93N

74LS95N 1

74LS107N

74LSI12N

74LEtl3N

74LS132N

74LS136N

74LS151N

74LS155N

MLS157N 1

74LS162rJ 1

74LS163N 1

74(.S174N 1

74LStS0N I

74LS221N 1

74LS2SaN 1

74L8367N

CA3046 1

CA3031 1

CA30B2 1

CA3089 2 LM301AN.'6H LM305H LM307N

LM30BN 1

LM309K 1 LM311H(N

LM317r 1

LM3J7K 3

LM31B 1

LM320K-5 1 35

LM32aK-12 1.35

LM320K-15 1.35

LM320T-5 .95

LM3Z0T-fl .95

LM320T-12 .95

LM320T-15 .95

LM323K-5 5.95

LM324N 1.00

LM33SN 1 00

LM34DK-5 1 35

LM340K-8 1 35

LM340K-12 1.35

LM340K-15 1.35

LM340K-24 1 35

LM340I-5 85

LM3iOI-B 85

LM340I-12 85

LM340T-15 85

LM340T-18 85

LU340r-24 ,85

LM3S0 5.50

LM377 2.95

LM379 5.00

LU3eON 1.00

LM3S1 1 60

LM382 1 60

LM709H 59 LM723H'N LM733N LM741CH LM741N LM747H/N LM74BN LM1303N LM1304 LM1305 LM1307 LM13I0 LU1458 t.M1B12

LMiesg

LM2t11 LM2902 LM390QN t.M3905 LM3909N MC1458V NE550N NES55V NESS6A NE565A NE566V NE5E7V NE570B 78105 7BL08 76M0S 75108 7549tCN 75492CN 75494CN

13.95

a700CJ 870ICN

875DCJ 13 95

LOnO 9 95

9400CJV/f 7 40

ICL7103 9.50

ICL7107 14 25

CMOS

CD4000 .25

CD400I .35

C040D2 35

CD40D6 1.10

CD4D07 .35

CD4008 1.20

CD4009 .45

CD4010 .45

CD40)1 .35

CD4012 .28

CD4013 .47

C04014 1.25

C04015 1 00

CD.1016 55

CQ.1017 1 05

CDilOIB .94

CO4019 .45

CD4020 1.02

CDJ021 1 35

CD4022 1 10

CD4023 .28

C04024 .75

C04025 .28

CD4026 C04027 CD4028 CD4029 CO403O CD4035 CO4040 :O4042 CO4043 CD4044 C04046 CD4049 CD4050 CD4051 CD4060 CD4065 CD4068 CDJ059 :D4070 CD4071 CD4072 CD4073 CO407S CD4076 CD4078 CD4081 C04082 CD4116 CD4490 C04507 CD450fl CD4510 CD45I1 CD4515 CD4516 CD451B CD4520 C04527 C0452B C04553 CD4S66 CD4S83 CD45S5 C040192 74C00 74C04 74C10 74C14 74C20 74C30 74C48 74C74 74C76 74C90 74C93 74C154 74C160 74C175 74C192 74C221 74C905 74C9D5 74C914 740922 R 74C923 74C925 74C926 74C927

Z.50 ?ii4L450n5 4,00

.66 «116 200ns 4.50

.85 3/411620ans26.95

135 MM52K .40

.45 MM528a 3,00

1.00 MM5320 9-95

1.35 MM5330

.85 P041ID-3

B5 30411D-4

-B5 P5101L

1-E7 420OA

-45 32S25

.60 91L02A

'13 HO0165-5

1 42 MM5710O

71 GIAYSeSOO-'

40 MCM66751A

40 9368

S6 pin adge 4.00 lOOpinBdge 4.50 100 pin Mob WW 5.2S

iC SOCKHS Soldsr Tin Low Pniflta PIN 1UP PIN 1UP

6 95 18 27 36 58 4 50 20 79 40 57

50

■ lOD

■*l CLOCKS

■jl MM5311

'■55 MM5312

*0 MM5314

11 MMS369

3= MM5841

■tl MM5B65

?=2 CT701D e.95

' go CT7015 8 95

f MM5375AA'N 3 90 MM5375AG(

•1 50 WIRE WflAP LEVEL 3

10 00 P'N P'N

16 00 ^6 24 93

16 49 28 1 OO

18 .67 40 1.59

5 50 CflYSTAlS

3 90 1 HHi 4 50

3 90 2 MHi 4 50

7 95

■205 7207 '208

2 52

Of DS0026CN DS0056CN

1 50 MM53104

2145 MICnOPRDC

2.35 S502

1 10 6504

3 00 B522

35 6800

40 6B02

35 6820

.89 6850

16 50 7.50 15.95

:85 780 .25 780A

9 95 n 95 2 90

6.95

10 95

8T10 8T13 BT20 8123 3124 8T2S BT26 8728

1 25 8212 1.25 8214 3 50 8216

2 75 8224 1,35 5228 1,65 8251 1 90 8253 6 00 8255

75 8257

1 95 8259 la.Mb

5 00 ■802CP Bias. 13.95

5 50 1B02DP plas. 17.95 7"5Q leeiP 9,50

6 95 CDPIBD2C0 28.95 CDS CDP18020 35,00

C0P181SP 7 95

65 UART/FIFO

65 AV5-1013 5.50

65 AV5-1014 7.50

65 3341 6.95

3,10 2716TI 3.50 !716 5Voll 3.20 6/2716 5 Vol!

5 MHi 4 25

10 MH; 4 25

IB MHz 3.90

20 MHI 3.90

32 MHz 3.M

3276B Hi 4,00

1.B432 MHi 4.50

3.5795 MHi 1.20

2.0100 MHz 1.95

' 2,097152 MHz 4 50

' Z.Am MHz 4.60

I 3.27EB MHz 4 50

I 5.0683 MHz 4.50

5.185 MHz 4.50

5.7143 MHz 4.50

6,5536 MHz 4,50

14.31818 MH: 4.25

1B 432 MH; 4.50

22 11B4MHZ 4.50

KEYB0AF1D ENCODERS

AY5-2376 SI 2.50

AY5-3S00 17,95

AY5-9100 10.50

AY5-9200 16.SO

74C922 5 50

74C923 5 50

HD0165-5 6 95

AY5-9400 10 50

D Conn acton RS232

OB25P 3 62

OB25S 5.20

Cover 1 67

DE9S 1.95

DA15P 2-10

DA15S 3.10 Complete Set

KEYBOARDS

56 key ASCII keyboard kit 167,50

Fully assenibied 77,50

53 ksy ASCII keyboard kit 60,00

Fully assembled 70.00

Enclosure Plastic 14,95

Metal Enclosufe 29.95

LEDS

RedTOIS .15 Grgen. Yellow TD18 .20 JumHo Red .20 Green, Orange, Vellow Jumbo .25 Cllpini LEO MnrnHng Cllpi asi.25 (specHy red. amber, green, ytilow. dear)

CONTINENTAL SPECIALTIES In slock

Comcieie line ol breadDcard tesi equip MAX-lOO 8 digit Frgq. Clr. 1149-95

tack S1S.IU

Complele line ol AP Produdt In ttock.

SPECIAL PRODUCTS

UM5B65 Slopnatch Timer

witn 10 p9 spec 9.00 PC board 7 50

SarllctiM Mom PusbbuHDn 27

Mode; 150 Bus Grabber Kit Clock Cilendir Kll

niANSFDRMERS

6V 300 ma 3 12 Volt 300 ma transformer 1 12 6V CT BOO ma 3 12V 250 ma wall plug 2 12V CI 250 ma wall plug 3 24V CT 100 ma 3 lOV 1 2 amp nail plug 4 12V 6 amp 12 12V 500 ma wall plug 4 12V 1 amp wall pluQ 6 lO.'lS VAC B'le VA wall ulug 9

OlSPUY LEDS

MAN1 CA 270 2

MAN3 CC 125

MAN7Zi74 CA CA .300 1

DL704 CC .300 1

DL707/DL707R CA 300 1

OL727/72a CAXC 50Q 1

9.50

1722

2102-1

2102AL-4

2102AN-2L

2104A-4

2107B-4

2111- 1

2112- 2

3.75

2U4L 300ns4.25

,75 2758 .59 S741A .G9 8748 8748-8 6755A RAMN82S23 .85 N82S123 .95 NB2S126 .45 NB2S129 ,65 NB2S131 .95 NB2S13E 75 NB2S137 .75 0M8ST7 ,95 8223

Hlrtak3KDlBllUDinul

iimiiir ig.es

SiDpwilch Kit 2I.BS AulD Clock Kll IT.gs DIgllel Clack Kit 14,95

RESISTORS wall 5«.i ID ni' lype 03 25 per type 025 100 por type 015 1000 pe' type .012 350 piece pack 5 par type 6.75 '/] wall 5% per type .05

0L747/75D FN0359 FNO50a5O7 FNDSOSIfSIO FNOBD0m7 3 digit Bubble ID digit display 7520 Claiiei pholocells TIL311 Hei MAN3540 CC

CAiCC 6D0 1

CC -357 CC/CA .500 1 CC/CA .500 CC/CA .SOO 2

MAN6640

MANE710 MANB74a

CC .40 CA 40 CC 40 CC .56 CA .BO CC .60

Televldeo Termlnel

MAIDOU. C. E

MAIDIZA

101P3 Innilonner

MA1012A Tnntlamitr

Dtp SwIlEhu

4- position t .95

5- positkm 1,00

S-posWon 1.0S

CempMs Um ol Kobbr-Blox lol. dwlmlimdboanli in stock. IC Starter PaA SS,95 Discrete Component Starlet Pack S8.BT

PROM Eraser

assembled. 25 PROM capacity $37.50 (with timer $69.50). 6 PROM capacity OSHA/ UL version $69.50 (with timer $94.50).

Z80 Microcomputer

16 bit I/O, 2 MHz clock, 2K RAM, ROM Breadboard space. Excellent for control. Bare Board $28.50. Pull Kit $99.00. Monitor $20.00. Power Supply Kit $35.00. Tiny Basic $30.00

S-1bO Computer Boards

8K Static Godbout Econo IIA Kit 149.00 16K Static Godbout Econo XIV Kit 269.00 24K Static Godbout Econo )(X-24 Kit 414.00 32K Static Godbout Econo XX-32 Kit 537,00 16K Dynamic RAM Kit 289,00 32K Dynamic RAM Kit 328,00 64K Dynamic RAM Kit 399,00 Video Interlace Kit $139.00

80 IC Update Master Manual $39.00

Comp. ICdata selector, 2700 pg. master reference guide. Over 51,000 cross refwences. Free update service through 1980. Domestic postage S3.50. Modem Kit $60.00 State of the art, orig., answer. No tuning necessary. 103 compatible 300 baud. Inexpensive acoustic coupler plans included. Bd. only $17.00. LRC 7000 +Printer $389.00 40/20 column dot matrix Impact, std. paper. Interface all personal computers.

64/40/32^0 version $405.00. Optional cables available.

LRC 7OO0 printer interface cable (or Super EH

Witti .S^3iL.Ya.-;r n bj

NiCad Battery Fixer/Charger Kit

Opens shorted cells that won't hold a charge and then charges them up, all in one kit w/full parts and instructions, $7.95

Rockweii AIM 65 Computer

6502 based single board with full ASCII keyboard and 20 column themial printer. 20 char, alphanumeric display, ROM monitor, fully expandable. $405.00. 4K version $450.00. 4K Assembler $85.00, 8K Basic Interpreter $100.00.

Special small power supply for AIM65a5sem. in frame $54.00. Complete AiM65 in thin briefcase with power supply $499.00. Molded plastic enclosure to fit both AIM65 and power supply $47.50. Special Package Price: 4K AIM. 8K Basic, power supply, cabinet $625.00.

AIM65/KIMA/IM/Super Bi 44 pin expansion board: 3 female and 1 ntale bus. Boanl plus 3 connectors $22.95.

60 Hz Crystal Time Base Kit $4.40

Converts digital clocks from AC line frequency to crystal time base. Outstanding accuracy.

Video Modulator Kit $9.95

Convert TV set into a high quality monitor w/o affecting usage, Comp, kit w/full instruc.

Multi-volt Computer Power Supply

8v Samp, ±18v .5 amp, 5v 1.5 amp, -5v ,5 amp, 12v ,5 amp, -12v option. ±5v, ±12v are regulated, Basic Kit $29.95. Kit with chassis and all hardware $43.95. Add $4.00 shipping. Kit of hardware $14.00. Woodgrain case $10.00.

RCA Cosmac 1802 Super Elf Computer $106.95

Compare features before you decide to buy any other computer. There is no other computer on the market today that has all the desirable bene

fits of the Super Elf for so little money. The Super Elf is a small single board computer that does many big things. It is an excellent computer for training and for learning programming with its machine language and yet it Is easily expanded with additional memory, Full Basic, ASCII Keyboards, video character generation, etc. Before you buy another small computer, see if it includes ttie following features: ROM monitor; State and Mode displays; Single step; Optional address displays; Power Supply; Audio Amplifier and Speaker; Fully socketed for all IC's; Real cost of In warranty repairs; Full documentation. The Super Elf includes a ROM monitor for program loading, editing and execution with SINGLE STEP for program debugging which is not included in others at the same price. With SINGLE STEP you can seethe microprocessor chip operating with the unique Quest address and data bus displays before, during and after executing instructions. Also, CPU mode and instruction cycle are decoded and displayed on 8 LED indicators. An RCA 1861 video graphics chip allows you to connect to your own TV with an inexpensive video modulator to do graphics and games. There is a speaker system Included for writing your own music or using many music programs already written. The speaker amplifier may also be used to drive relays for control purposes.

plus load, reset, run, wait, Input, memory protect, monitor select and single step. Large, on board displays provide output and optional higli and low address. There Is a 44 pin standard connector slot for PC cards and a 50 pin connector slot for the Quest Super Expansion Board. Power supply and .sockets for all IC's are Included in the price plus a detailed 127 pg. Instruction manual which now includes over 40 pgs. of software info, including a series of lessons to help get you started .and a music program and graphics target game. Many schools and universities are using tiie Super Elf as a course of study. OEM's use It for training and R&D. Remember, other computers only offer Super Elf features at additional cost or not at all, Compare before you buy. Super Elf Kit $106.95, High address option $8.95, Low address option $9.95. Custom Cabinet with drilled and labelled plexiglass front panel $24.95. All metal Expansion Cabinet, painted and silk screened, with room for 5 S-IOO boards and power supply $57.00. NICad Battery Memory Saver Kit $6.95. All kits and options also completely ^sembled and tested.

Questdata, a software publication for 1802 computer users is available by subscription for $12.00 per 12 issues. Single issues $1-50. Issues M2 botjnd $16.50, Tiny Basic Cassette $10.00, on ROM $38.00, original Elf kit board $14.95. 1S02 software; Moews Video Graphics $3.50. Games and Music $3.00, Chip 8 Interpreter $5.50.

A 24 key HEX keyboard includes 16 HEX keys

Super Expansion Board with Cassette Interface S89.95

This is truly an astounding value! This board has been designed to allow you to decide how you want It optioned. The Super Expansion Board comes witb 4K of low power RAM fully addressable anywtiere In 64K with built-in memory protect and a cassette Interlace. Provisions have been made for all other options on tfie same board and it fits neatly into the hardwood cabinet alongside the Super Elf. The board includes slots for up to 6K of EPROM (2708, 2758, 2716 or Tl 2716) and is fully socketed. EPROM can be used for the monitor and Tiny Basic or other purposes. A IK Super ROM Monitor $19.95 is available as an on board option in 2708 EPROM which has been preprogrammed with a program loader/ editor and error checking multi file cassette read/write software, (relocatable cassette file) another exclusive from Quest. It Includes register save and readout, block move capability and video graphics driver with blinking cursor. Break

Quest Super Basic V5.0

A new enhanced version of Super Basic now available. Quest was the first company worldwide to ship a full size Basic for 180z Systems. A complete function Super Basic by Ron Cenker including floating point capabllify with scientific notation fnumber range ±.17E"). 32 bit integer ±2 billion; multi dim arrays, string arrays; string manipulation; cas

polnts can be used with the register save feature to isolate program bugs quickly, then follow with single step. If you have the Super Expansion Board and Super Monitor the monitor Is up and running at the push of a button. Other on board options include Parallel Input and Output Ports with full handshake. They allow easy connection of an ASCII keyboard to the input port. RS 232 and 20 ma Current Loop for teletype or other device are on board and if you need more memory there are two S-100 slots for static RAM or video boards. Also a IK Super Monitor version 2 with video driver for full capability display with Tiny Basic and a video interface board. Parallel I/O Ports $9.85, RS 232 $4.50, TTY 20 ma l/F $1.95, S-100.$4.SO. A 50 pin connector set with ribbon cable is available at $15.25 for easy connection between the Super Elf and the Super Expansion Board. Power Supply Kit for the complete system (see Multl-vdit Power Supply).

Ohio Scientific Computers

CIP Series 2 $455.00. Like an Apple at less than half the price! CIPMF Series 2 $1199.00. Minifloppy version with additional RAM/ROM. Complete software and peripherals available. Send for free brochure.

Gremlin Color Video Kit $69.95

32 x 16 alpha/numerics and graphics; up to 8 colors with 6847 chip; IK RAM at EOOO. Plugs inio Super Elf 44 pin bus. No high res, graphics. On board RF Modulator Kll $4.95

1802 1 6K Dynamic RAM Kit $149.00

Expandable to 32K. Hidden refresh w/clocks up to 4 MMz w/no wait states. Addl, 16K RAM $63.00 Tiny Basic Extended on Cassette $15.00 (added commands Include Stringy, Array, Cassette I/O etc.) S-100 4-Slot Expansion $ 9.95 Super Monitor VI,I Source Listing $15.00

sette I/O; save and load, basic, data and machine language programs; and over 75 statements, functions and operations. New improved faster version inctudino renumber and essentiEilly unlimited variables. Also, an exclusive user expandable corhmand library.

Serial and Parallel I/O Included. Super Basic on Cassette $55.00.

Eif II Adapter Kit $24.95

Plugs into Elf II providing Super Elf 44 and 50 pin plus S-100 bus expansion. (With Super Expansion). High and low address displays, state and mode LED's optional $18.00.

Super Color S-100 Video Kit $129.95

Expandable to 256 x 192 high resolution color graphics. 6847 with all display modes computer controlled. Memory mapped. IK RAM expandable to 6K. S-100 bus 1802,8080,8085, Z80 etc. Dealers: Send for excellent pricing/margin program.

Editor Assembler $25.00 (Requires minimum of 4K for E/A plus user source)

1802 Tiny Basic Source listing $19.00

Super Moniift -"O 00

TERMS: $5,00 min. order U.S. Funds. Calif residents add 6% tax.

SIO.OO min, BanlcAmericard and Master Charge accepted. $1.00 insurance oplional. Postage: Add 5%. CCD. $10,00 min. order.

FREE: SB QUEST CA

?.t n I f iii lift irn rt!. Ml rvuVi

Circle 342 on Inquiry card.

BYTE May 1981 479

Circle 391 on inquiry card.

SUNNY LOW LOW COST

POWER SUPPLIES

FOR S-100, FLOPPY DISKS.

R3

For Three 8" or 5V4" Disk Drives

S-100 POWER SUPPLY KITS (open frame wiiH base pu^te, 3 hrs. assy, time)

USED FOR

@ + 8 Vdc

@ - 9 Vdc

@ + 16 Vdc

SIZE W X D X H

S3 2 in 1 Unit for S-100 and two 8" or 5'm" Disk Drives. It fits most Disk System IVtainframes.

PRICE

KIT1 15 CARDS SOURCE 15A KIT 2 SySJEM SOURCE 25A KIT 3 DISK SYSTEIvl 15A

1A

2.5A 3A 2A

2.5A 3A 2A

4A

1,2" X 5" X W 12" X 5" X 4'/8" 14" X 6" X 4'/b"

52.95 59.95 67.95

DISK DRIVE POWER SUPPLY "R3" regulated, open frame, assy & tested 67.95

SPECS: + 5V @ 5A OVP, -5V @ 1A + 24V@ 5A, SHORTS PROTECT 2 SIZES AVAIL.. 1.) 9" (W) x 6'm ' (D) x 4%" (H), 2) 9" (W)x 5%" (D) x 5Vi" (H)

OPTION: 1.) REPLACE + 24V BY + 12V. 2.) FOR SIZE 1 ONLY. ADD +. 12V @ 1A. AT AN ADDITIONAL $12 00

IDEAL FOR THREE 8" or 5V4 FLOPPY DISK DRIVES, SUCH AS SHUGART 801/851. SIEMANS FDD 100-8/200-8 OR 100-5 ETC

DISK SYSTEM PWR SUPPLY "S3" open frame, assy. & tested, compact size; io"(w) x 6" (□) x 5- (h) 92.95

REGULATED OUTPUTS FOR DISK DRIVES: +5V @ 4A, -5V @ 1A, +24V @ 4A (OR + 12V @ 4A), SHORTS PROTECT

UNREGULATED OUTPUTS FOR S- 100: +8V @ 14A, + 16V @ 3A, (OPTION: ADD OVP FOR +5V, ADD $5,00)

A COMPLETE UNIT FOR DISK SYSTEM WITH THE MAINFRAME CONTAINING 12 SLOTS & TWO 8" or S'A" DISK DRIVES,

POWER TRANSFORMERS (with mounting brackets)

ITEM PRIMARY SECONDARY #1 SECONDARY #2 SECONDARY #3 SIZE W x D x H PRICE

Tl T2 T3 T4 T5

110/120 110/120 110/120 110/120 110/120

2x8 Vac, 15A 2x8 Vac, 25A 2x8 Vac, 15A 2x8 Vac, 6A 2 X 8 Vac, 8A

28 Vac, CT, 2.5A 28 Vac, CT, 3.5A 28 Vac, CT, 2.5A 28 Vac, CT, 1.5A 28 Vac, CT, 2A

48 Vac. CT, 2A 48 Vac, CT, 3A

3%" X 3%4" X 3W' 3%" X 4%" X 3Ve ■ 3%" X 4%" X 3Va" 3%" X 3%" X 3V8" 3" X 3" X 2V2"

21.95 27.95 29.95 22.95 14.95

SHIPPING For eacti power supply $5,50 in Calif,. $7,50 in other states, $14,00 in Canada For eacti Transformer $5.00 in all States $10 00 in Canada. Calif. Residents add 6% Sales Tax.

MAILING ADDRESS: SUNNY INTERNATIONAL shipping ADDRESS:

P.O. BOX 4296 (TRANSFORIVIERS MANUFACTURER) 22129V2 S. VERMONT AVE

TORRANCE, CA 90510 (213) 328-2425 MON-SAT 9-6 TORRANCE, CA 90502

oppkllphi/

]with48Kof s memory!

51199

twilh Ihepurchase ot ] Ihe APPLE II \$elect Ifomihe beluw' ISPECIAL ppicing:

m&asel printer ^599" lO/sAUW/conl .,585'

Id/s» (/ 475'

ISer/V/n/erCrf. I?9-'

|suon»»o</. 23

pwayIJOSelect..

Video 100 e:.... 1/9' jFtrmwareCarri. /j9' iOHFjoJ

nSSoO .26 74LS155 11S

74LS02 .26 74LS158 75

74LS03 26 74LS160 95

74LS04 26 74LS161 85

74LS08 28 74LS162 95

I 74LS09 26 74LS163 160

TnLSIO .26 74LS164 65

74L'S2C .26 74LS165 55

I74LS21 28 74LS170 175

174LS22 26 74LS174 75

I 74LS26 49 74LS175 75

174LS27 .26 74LS190 75

I 74LS30 28 74LS193 96

I74LS32 .32 74LS195 96

1 74LS38 .32 74LS196

74LS42 .65 74LS221 140

74LS48 .78 74LS240 165

74LS51 .25 74LS241 165

I74LS54 35 74LS243 145

I74LS74 38 74LS244 145

I74LS7 5 60 74LS245 2 25

174LS83 .44 74LS253 95

I74LS85 95 74LS257 95

I74LS86 .95 74LS2S8 96

174LS90 69 74LS259 2 85

I74LS93 .69 74LS279

|74LS107 45 74LS283 1 00

l74LSt12 .38 74LS293 185

I74LS113 .48 74LS298 120

I74LS122 .48 74LS366 95

I74LS123 .96 74LS367 55

I74LS126 .69 74LS368 SS

I74LS13S 69 74LS373 139

I74LS1S1 .44 74LS374 139

I74LS153 .44

kll/oppkllplu/

mh64Kpf memory!

^1415.

Ami UVraiMCt CMUM

cunnonKi Minnii t s

APPLE EXPANSION Kll | L6K MenHKyAdd-On

^39°

'129

12

K Cofp

COLOR

2708 IkxB 5.95 e FOR 40 .00 27t6 2h X 8 9.95 wngifl p 3 B FOR 80.00 2732 4k X 8 24.95 2716 2k K 8 6 K tfipit pii.

E)nboaftf5iipfMaiiiWiofiB>g«r<ilb.

Lh»sMSMS83Z-crys$atcoitroaod.

(alifomia (.omp(Mfr Syslnns

MISCELLANEOUS

803SC

2.S5

NES55V

27

7805

7906

7915

79ie

7806

7806

7806

7812

MC1330UP

1 60

MC13S0P

1 15

laciassp

1.50

LM380N

1.75

NE965N

1 25

MC14S8P

50

1^410 SCR

.95

IT410 rn/4c

.96

2114 200<n

3.50

2114L 300n«

3.75

2114L 200ns

4.2S

4116 300na

4.96

4116 200n»

S.4S

. LOCIC ^ KIT

BUY FIVE OR MORE FOR ....S1B.9S each

CONCORD

COMPUTER PRODUCTS

1971 SOUTH STATE COLLEGE

ANAHEIM. CALIF. 92806

VISA HASTERCHARGE MINIMUM ORDER 'lO 00 CHECH on M O ^— - ^ ADO»i 50 FOR FBT OW |

i714j937'0637 p'"'"^

VISICALC

for: uppLf &

^ ATARI

3)-|30oo

5 or more 20.00

SN7 SN7402N SN7404N SN7408N SN7410N SN7412N SN7413N SN7414N SN7416N SN7417N SN7423N SN7425N SN7430N SN7437N SN743BN

20 SN7440N 22 SN7442N 22 SN7443N

24 SN7445N

22 SN7451N

28 SN7454N 35 SN7474N 49 SN7475N

29 SN74 82N 29 SN7492N

28 SN7493N

25 SN7495N

23 SN7496N

29 5N74122N 7i SN74136N

MSM5832 ? MICROPROCESSOR REAL-TIME CLOCK

22 SN74141N

57 SN74151N

78 SN741S3N

78 SN74154N

20 SN74155N

20 SN74157N

32 SN74160N

32 SN74161N

1.05 SN74153N

.50 SN74164N

.48 SN74155N

.60 SN74174N

.70 SN74175N

39 SN74180N

.95 SN74181N

69 .65 .65 1 25 .80 .69 95 65 85 87 .87 95 69 75 1.15

74S

•noMff in«til-o»tii'.Mn', IF ■I IHI 'uni tmn* n * '0*11'tW elw k • riifi''!*' i'-rn|Miniii(i||iiH.PUO< «ppllLdI■l)n^ ,i, VSU> Lonlinllei) m.111*!'!' iimr UW • (xtrntSr 4CM'e^Mbif * l»< >. <i taM "1 SEI.mDH « MOuns DAV U( WtEK DATt MTJNtH ditd (E* , (onioiiva * b<i 4a(i'"\'. i n<ti 'ei how) moull nil'' F.,.., l.,,n^ ■ ■ ,ir i Ii.fft

. TRS80 •4395

I KIT CONTAINS I nP SWITCHES lANODErAILED IlNSTBOCnoNS

SOROC

NOCOO

c*L RES Ana B/

IF OVER *iO

I No"Glilches"»SurKes Or Interference

THE MPonr TURNS AN ORDMAflV OUTLET IWTO A COWTROLLED ITLTTnEO

POWEB sOuncE ton up

TO ECMT Devices

480 vmMvim

circle 99 on Inquiry card.

1858 Evergreen Street, Duarte, California 91oTo'"

Phone 213-357-5005

page

DIGITAL INC.

INSULATION DISPLACI

lOCKETS

RIGHT ANGLE HEADERS

« t

Plm

10 IDH10SR .80 20 IDH20SR1-2S 26 IDH26SR1-85 34 IDS34SR2-15 40 IDH40SR2-50 50 IDH50SR3.1S EJECTOR EARS .25

Wnp

IDH10WR 1.75 IDH20WR 2.75 IDH26WR 3.60 IDH34WR 4.15 IDH40WR 4,90 IDH50WR 6.15 EACH

2S PIN "D" CONNECTORS

ttyM Pan •

SOLDER STYLE Male DB25P .2.25 Female DB255 3.00 Hood DB25C 1.10

INSULATION DISPLACEMENT Male IDC25P 4.95 Female IDC2S5 5.25 Hood IDC2SC 1.35

■

I

CARD EDGE CONNECTORS

Plm

Part No.

10

IDE10

3.25

20

IDE20

3.50

26

IDE26

4.05

34

IDE34

4.85

40

IDE40

5.65

50

IOE50

5.90

RIBBON CABLE

^nduetoia: Solid Color

Color Coded

SOCKETS

Pins

Pan No.

Slain Rgllal

10

IDS10

1.25

.25

20

IDS20

2.02

.25

26

IDS26

2.65

.25

34

IDS34

3.50

.25

40

IOS40

4.05

.25

50

IDSSO

5.06

.25

^8

ion.

1S0H.

10 ft

IN ft

10

2.90

17.00

4.00

30.00

14

3.40

23.80

5.00

42.00

16

3.70

27.20

5.60

48.00

20

4.40

34.00

7.00

60.00

24

5.00

40.80

8.00

72.00

26

5.40

44.20

8.60

78.00

34

6.80

57.80

11.00

102.00

40

7.80

68.00

13.00

120.00

50

9.50

85.00

16.00

150.00

CABLE PLUGS

pins

Part No.

14

IDP14

1.25

16

IDP16

1.40

24

IDP24

2.25

40

IDP40

3.65

WIRE WRAP WIRE

WIRE KITS

Length 100/Bag 500/Bag 1K/Bag Length 100/Bag 500/Bag IK/Bag Kit No. 1

2.5"

$1

25

$3.58

3.0"

1

30

3.86

3.5"

1

37

4.15

4.0"

1

42

4.44

4.5"

1

48

4.74

5.0"

1

54

5.04

5.5"

1

58

5.38

6.0"

1

65

5.66

$9.95

Kit No. 3

$32.95

E 6.19 6.78 7.37 7.94 8.54 9.13 9.72 10.31

6.5"

$1.92

$6.44

$1 1.81

7.0"

1.99

6.76

12.44

7.5"

2.08

7.07

1 3.09

8.0"

2.14

7.38

13.73

8.5"

2.18

7.69

1 4.36

9.0"

2.24

8.1 1

1 5.01

9.5"

2.30

8.32

1 5.65

10.0"

2.39

8.71

16.28

250 3" 100 4'/2' 250 3'/2" 100 5" 100 4" 100 6"

500 2'/a'

500 3"

500 S'/j'

500 4"

500 4'/2'

500 5"

500 6%'

500 6"

Kit No. 2

$24.95

Kit No. 4

$59.95

Kynar precut wire. All lengths are overall, including 1" strip on each end. Colors and lengths cannot be mixed for quantity pricing. Choose from colors Red, Blue, Black, Yellow, White, Green, Orange, and Violet.

250

2V2"

250

5"

1000

2'/2"

1000

4'/2

500

3"

100

5'/?"

1000

3"

1000

5"

500

3'/2"

250

6"

1000

3y2"

1000

5"

500

4"

100

6'/2"

1000

4"

1000

6"

250

4'/2

100

7"

ORDERING INFORMATION:

Orders under $2S Include $2 handling All prepaid orders shipped UPS Ppd^ Visa, MC & COO'S charged shipping. All prices good through cover date,

' Most orders shipped same day.

' Byte must tie mentioned to get sale price.

Writ* or call for 1W1 eitatog

• IC Sockets

• Vector Board & Pins

• Bishop Drafting Aids » OK Tools

• RN IOC Crimp Connectors

"NEW" WIRE WRAP SOCKETS FEATURING A SELECTIVE PLATING METHOD THAT WILL SAVE YOU MONEY BY HAVING GOLD ONLY WHERE IT COUNTS.

size Quantltv/TubeiPrlce ea.* Price/Tube

GOLD PLATED CONTACTS

TIN PLATED TAILS

3 Level closed entry.

RN Side Wipe contact design gives twice the contact area for high reiiabiiity.

8

52

.41

21.32

14

30

.47

14.10

16

26

.51

13.26

18

23

.70

16.10

20

21

.87

18.27

22

19

.94

17.86

24

17

.96

16.32

28

15

1.25

18.75

40

10

170

1700

•FOR REFERENCE. MUST BE ORDERED IN TUBE QUANTITIES.

QUARTZ CRYSTALS

S.Z4Z8'B

9.933S-6

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36iB86-B

42.8518 8

468128-8

5390-B

5.610-B

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43.IS584

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30^038-8

4325040

40.7006-8

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433334B

417338-8

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28.4006-8

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28.6276-8

39.8768-8

43.40708

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3.Q67'B

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40 4448-S

43.4446-8

51J1288

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7.00G3'B

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29.93788

40.5928-8

43.5553-8

51.7778'B

3.500-B

7.0336 B

II 6816B

3ai)648'B

40.6128-8

43.629B-8

51.8506-B

7.0S16-6

12.440 B

303eOG-B

4083364

43M68B

52.B 126-8

4.000 B

7.IB36'B

I43IBZ-8

30.82584

404nB4

43J774B

56,7506-8

4.I943B

7.Z586B

14.4306-6

30876S4

4UBI84

4341204

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4.MZ6B

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31.43784

409258-8

4341448

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31.75384

4lil0064

66.7S064

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3110084

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70:4000-0

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4342540

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8.3303 8

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337006-8

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8 4998-8

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42X10088

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17 242Z-B

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425B36B

44.3768-8

100.66684

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a 6056 B

181300 B

34.7538-B

42£268-B

44.77784

101.4666-8

5.1Z03B

B.9eOB'B

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34£77frB

42.7006 8

45.12584

IQ3.0668B

5.1650-B

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48.70064

10440104

ALL

ALL 8 -1)59

10 OR MORE

OEOUCT S^c

ADD SI 00 SHIPPING CAL. RES. ADD 6% SALES TAX FREE OSCILLATOR SCHEMATICS WITH ANY ORDER

QUALITY COMPUTER PARTS P.O. BOX 743 / CHATSWORTH, OA 91311

Circle 338 on Inquiry card.

NEED DISKETTES?

Call free (800)235-4137

3M

BASF

MEMOREX

^Dysan

PACIFIC EXCHANGES

100 Foothill Elud

San Luis Obispo. CA 93401 (In Cal ce (805) .543-1(137 i

Circle 313 on inquiry card.

PROOF

IS HERE

*PROOFREADS SPELLING

*FINDS TYPOGRAPHICAL ERRORS ♦CHECKS OVER 250,000 WORDS *USER EXPANDABLE DICTIONARY *SIMPLE TO USE ♦COMPATIBLE WITH ALL:

Z80t CP/Mt TEXT FILES

TRS-80+ SYSTEMS *FAST

$150

IPS

IMAGE PROCESSING SYSTEMS 6409 Appalachian Way Madison, Wisconsin 53705 (608) 233-5033

Also available: Screen Ed/tor — $75 f Registered Trademark

Circle 190 on Inquiry card.

Budget Software

For as little as 15% down you can have custom designed software, write BUDGET SOFTWARE, 8517 Nestle Ave., Northridge, CA,, 91325 or phone (213) 701-0734 8:00 - 5:00 (pst)

GREAT DEALS ON SOFTWARE

MICROPRO

WORDSTAR'" MAILMERGE'" DATASTAR'SUPERSORT I'SUPERSORT H"

S 320

$ 100

S 230

$ 165

S 130

SMALL BUSINESS APPLICATIONS, INC.

MAGIC WAND'" S 270

CPU INTERNATIONAL

PEARL I'" $ 100

PEARL II'" S 295

PEARL III" $ S4n

INNQVATIVE SOFTWARE APPLICATIONS SPELLGUARD'" $ 275

SPECIAL

DIABLO 630 PRINTER S1995 30 DAY omit LIHITED QUAMTITIES AVAILABLE

H

DWP Inc. <'0'>2^' ^-^'o CB

12? Rmveil Cnuri , F.ills Chureh,\'irpinia 22ll4h

Circle 137 on Inquiry card.

LISP

Interpreter for the TRS-80*

See the August, '79 issue of byte to find how easy it is to

USE LISP.

■ Includes more than 30 functions a predicates.

■ Coded for high-speed

operation.

■ Full arithmetic CAPABILrrv.

■ User's Manual.

■ Supplied on CASSETTE FOR 16K64k level ii.

Send $50 in check or money order

TO:

Cyber Innovations World Trade Center

P.O.BOX 58657 Dallas, Texas 75258

'TRADEMARK OF TANDY CORPORATION

Circle so on Inquiry card.

Circle 109 on inquiry card.

TYPRINTER 450 $2100

45 char/sec daisywheel printer/ terminal. rs2321 ideal for word processing; will support diablo, qume. and nec protocols

TYPRIIMTER 550 $2300

SAME AS ABOVE BUT

55 CHAR/SEC PRINT SPEED

QUME $1000

55 CHAR/SEC OEM PRINTER MECHANISM

SHUGART 8"FLOPPY

DISK DRIVES $360

SA8OO SOFT-SECTORED SINGLE/DOUBLE DENSITY

MICROSWITCH KEYBOARDS$85

HALL EFFECT. ASCII MOD. 74SWI2

INTERFACE $325

OEM DAISYWHEEL PRINTER INTERFACE. INTERFACES DIABLO OR QUME OEM PRINTER TO RS232 OR CENTRONICS PARALLEL

RIBBONS $2.50

DIABLO HYTYPE 1 OR QUME. CLOTH OR MULTI/STRIKE. 1 DOZ. MINIMUM

211 WHITEWATER G REER, S.C. 29SS1 • (803) 244-7872

Apptoll

FUOHT nuim

Flight Plans Suitable for Jets to J-3'5 YOU ENTER: Deporture Point'

Destination

Altitude

APPLE 11 selects VOR navigotionol stotlons and prepares on optimoi flight plan Works RNAV flight routings tool Plans flights as high as FL 510 and os low as 1000 AGL. Flight plans ore tailored to cruising altitude. Allows for preferred VOR departure and arrival fixes. Contains in storage locations of all VOR navigational stations and 900 + airports Allows entry of doto for airport locations not conlorned in storoge.

Developed by Professional Pilot and flight proven since 1978.

FLIGHT PWNNER software t49.95 Documentation manual only i 5.00

Available thru your local APPLE Computer Dealer

or

Illinois Computer Mart, Inc.

Route 6, Sweet's Comer Plaza

Corbondole, Illinois 62901

Designed for the APPLE II by J.L Kennedy

Deoler Inquiries Invited

APPLE II isotradanarlt of APPLE EOMPUTER, Inc.

CENTRONICS lOlA PRINTERS, 9x7

matrix, 165 CPS, 132 col., normal tractor feed paper, up to 5 copies, width variable from 4"-15", 6 lines/ inch, 10 CPI, parallel data input, full 90 day wairanty (Wt. 118 lbs.) $6SO.0O

I.B.M. SELECTRIC KEYBOARD

PRINTERS, (Model 72) with GTE interface electronics to standard RS-232 Serial 25 pin connection. 15 CPS, 15 inch carriage, 10 pitch interchangeable elements, 90 day warranty (Wt. 50 lbs.) $650.00

(Pa. residents add 6% sales tax to orders) Malce checks or money orders payable to: American Custom Electionic

Systems Box 157A Groveland Rd. Pipersville, Pa 18947

C^d .50 per pound shipping/ handling lee)

Circle 82 on Inquiry card.

circle 20 on Inquiry card.

The Nanocomputen the professional approach to microcomputers

TheNanocomputer is an integrated educational system based on a powerful microcomputer with education-oriented software and complemented by aseries of training bool<s written specially for the system. POWERFUL— based on the Z80 microprocessor made by SGS-ATES

COMPLETE — hardware, software and peripherals backed by a series ot step-by-step training bool<s on programming, digital etectronics and interfacing.

MODULAR—as ttie student learns, ttie iiardware can be expanded to introduce new concepts and experiments: Z80 code programming, interfacing and tiigivlevei languages (BASIC). NBZ80S Nano Computer Includes the Nano Computer with power supply, the NEZ80 bread board for experiments and interfacing, the card frame, K1Z80 Cable Kit, the technical

manual and training books one and three $570.00

K1Z80 Extra K1Z80 Cable Kit 11.00

K2Z80 Active and experimental component kit 33.10

K3Z80 Socket kit with 3 40 pin sockets 5.70

^ RCZ80/P Cassette recorder for all Nano

/^^^^ Computer Systems (requires a W10Z80

. ^^K&f see below) 88.60

V^S^ W10Z80/P Cable for connecting the JjtmKKKKi FI<^Z80 cassette recorder 16.60

NEZ 2KB Experimental Software for the Nano Computer (available on the M2708 EPROM) 32.^

MINIATURE DOT MATRIX IMPACT PRINTER

MODEL DP-822

The Unique New Printer That Gives You All These Exciting Features.

• Uses standard 2Vt" adding machine tape or carbonless paper

• Low Cost

• Disposable printing head

• Simple interface

• Handles any type font

• Needs only one 12volt DC power supply

ideal Printer For

• Automated banking terminals

• Desktop calculators

• Electronic cash registers

• Medical and scientific instruments

• Industrial measurement, process and control systems

S Mini-microcomputers business professional and hobby

• 21-column printing at 25 lines per second

• Easy to install and maintain

• Point-of-sale (POS) terminals

a Security monitoring systems

• Emergency vehicle data receivers

• Fast-food kitchen printers

• Telecommunications equipment

. .and many more!

Model DP-822 $70.00

VIC-20

LOW PRICE COMPUTER from COMMODORE

PERSONAL COMPUTER

• 5K (Expandable to 32K)

• FULL SIZED TYPEWRITER KEYBOARD

• GRAPHICS CHARACTER SET

• 22 CHARACTER X 23 LINE SCREEN DISPLAY

• COLOR • SOUND

• EXPANSION PORTS

• RF MODULATOR

• PROGRAMMABLE FUNCTION KEYS $00095

• PET BASIC

HITACHI

64 K DYNAMIC RAM

FACTORY PROMOTION

KIT !145

KIT INCLUDES:

• 10pes 64K Dynamic Ram p/n HM4864-3 (200ns)

• Data Sheet

• Cross Reference List

FIRST COME

FIRST SERVED

* Quantity Limited *

ifujkbI

HANDHELD and BENCH/PORTABLE

DIVIM's

thondor PORTABLE

OSCILLOSCOPE

MODEL 8050A $349

AUTOMATIC CIRCUIT FOR UNUSED SECTIONS

DC-IOMHz 2" Diagonal CRT SMALL SIZE

|tO-<S.8->i2|

UlTMUW POWER

CONSUMPTION

■-■f=ir^

Synerlek Systems Single Boorcl Computer ujlth Kevboord/Dlsplav

SVM-1

10 Megahertz

HM307

SINGLE TRACE OSCILLOSCOPE IDEAL SERVICE INSTRUMENT TIME BASE 0.2 fxs - 2.0 s/cm LPS-TRIGGER ■ COMPACT BUILT-IN COMPONENT TESTER

Only $404.25

STORES 00 NOT ACCEPT MAIL ORDERS

MAILORDER

P.O.BOX220BY CULVER CITY, CA 90230

PHONE ORDERS (213) 841-4064

MnHmimQnfrSIOOO AM$2.0010compoiUgtwdhMHng.UMtnCluigi «id VISA wtlcgmMl niWMli4iftwiAaq(cii4iiuidMt.ntMtaulinuiiibi(ind upmiKin d»ii Soin Mmm on nibtKt Is piitf Mit. Not wponM tot tvpoi Stort (Kictng miv vwv fntm Miil Ordtr pricing. Wi num thi lij^ to ubtliniii

Synertek Systems Keyboard Terminol Module

• 24 X 40 Character Screen Size

KTM-2 $349

• 24 X 80 Character Screen Size

Universal Oscilloscope Probe

KTM-2/80 $424

00

SWITCHABLEXl and XIO Attenuation Factor

KEY ADDITIONAL FEATURES: • lOOMHz bandwidth • Heavy duty tip • Break resislanl center conductor • Slender, flexible cable

• 6fl. cable length • Wide compt-nsalion range • Fits all scopes

• Ground reference can be activated ai lip • Includes SPRUNG HOOK. I.e. TIP, BNC ADAPTOR. INSULATING TIP and TRIMMER TOOL ACCESSORIES.

VISIT A STORE NEAR VOU TODAY - We stoch a large selection of Tachniciil Books, Qiscrste Camponents, Intagrateil Circuits, Test EquipmanI anil Electronic Supplias.

ATLANTA

3330 Piedmont Rd. N.E. Atlanta, GA 30305 14041 261-7100

CULVER cin

1 1080 Jefferson Blvd. Culver City, CA 90230

(2131 390-3595

HOUSTON

2649 Richmond Houston. TX 77098

(713) 529-3489

PORTLAND

1 125 N.E. 82nd Ave. Portland, OR 97220

(5031 254-5541

SANTA ANA

1300 E. Edinger Ave. Santa Ana, CA 92705 (714) 547-8424

SUNNYVALE

1054 E. El Camino Real Sunnyvale, CA 94087 (408) 243-4121

TUCSON

4518 E. Broadway Tucson, AZ 85711 (602) 881-2348

Circle 24 on Inquiry card.

B¥TEMayl981 483

PRINTm

BASE 2

850

$735

APPiE IWTr.

$140

$ CALL 5

^82

$ CALL $

EPSON

$ CALL $

MX-80

MX-70

$ CALL $

ANACOM

S CALL 5

150

*ni4Sf MO Foi MM rp onon

1 rECNWCAl IMNOVAnONS |

1 P.O. BOX 803 1

1 NHISBOM, Off 97123 1

1 503-648-6423 |

Circle 399 on Inquiry card.

CP/Mi"^68XX

CROSS-SOFTWARE including source code in "C"

ASSEMBLER FEATURES: 2-pass absolute assembly Full Instruction set, Motorola-compatible Free-format input

Unlimited length labels Arithmetic expressions in operands Sorted symbol table output Intel format tiex output

PACKAGE A6800... MC6800/MC6802/MC6808

PACKAGE A6801 MC6801/MC6803

PACKAGE A6809 t^C6809

B" soft-sectored disk format, w/manual... $100.00

5" North Star disk format, w/manual $100.00

Manual and listing alone $ 85.00

(Wisconsin residents please add 4% tax)

\5

introl corp<^

647 W. Virginia St. ' Visa and

Milwaultee. Wl 53204 Master Charge

(414)276-2937 Accepted

CP/M is a trademark of Digital Research

Circle 204 on Inquiry card.

6800 Micro Modules

III

?? APPLE*-ITIS ??

Hardware or Software Problems?

Save time and money by having your own diagnostic disl<. Determine immediately if you have a hardware problem.

XPS's APPLE*-CILLIN can

help you cure your problems fast and easily.

Order APPLE*-CILLII\I for

$29.95* ♦

'XPSutc.

323 York Road Carlisle, PA 17013

' trademark of Apple Computer Inc. •*PA Residents add 6% sales tax

Requires 48K and one Disk II*

Circle 448 on inquiry card.

LUQER

. I. GODBOUI UOUON DTMtlTTf ^

0 tP^ON HOHTPISTAIl C.tTOH

Cnputsr SyitEM Inc. Hil .... .JT Hiinfrw [O Proviilon for J fi" Orivei wtih nowi iu[ipllf> 5'S. il',

,1 minfrw « I'rovi.lm (or I Hlnl-Drlvt. (SI,) v/po«r •upplv (On WO

. .. . w vith Dml » Vamm SKM DnvM cm i.i itss. !si! r. SrtioB Punbuid tv» SUOER cob Inc Mmuntifii PicUii (CBASIC SEqUIREDJ

' - ■ ■■ ■> Oimtliln U«l «». »1.

pcMT tiwly 1". I'S.

im ait)! KHr nnlir 2TS, 2U.

I IK ra ( Sk Anil Mm.| I». 2U. , Venillony t or It I 3C 2/1 IS.

» inlliblc * IIW.J its! ])T.

n» Kltm, Avill. « lirs.) IIS. 202.

-oiLt ifiih torthtui I CiBKo ers. stt.

mHjhb! fS CSC oThts wll

: ilitlc ra.ami.PuulU, SSI UU. call

II MU altli lilH IrK.-) 2101 ns. 2M. smi ttxaiiA Jddmiint ^itaa Eitcnlcd Uilnii ( I

pivrr ti^ly n«kl2S

■ PO EiDX RSI

— TIM QqS l7Hb I

Circle 369 on inquiry card.

COMPUTERS

CIP SERIES II - $479 00

OUR PRICE - $399.00

other OSI discounts available

CALL NOW TOLL FREE

1-800-558-0870

COMPUTERS PLUS, IIMC.

9 749 S IQBth St. MILWAUKEE. Wl 53227

(414) 321-1770 IN WISCONSIN

RUN BIG PROGRAMS

ON YOUR MODEL 1 TRS-80''

WITH 39 or 54K of use space.Can use Mixed Drivers S'A or 8" (Variable Tracks) Compatable with all TRS*80 Operating Systems and all TRS*80 F>rograms.(usable on 48K disk systems only) Boards fit Into keyboard inclosure.

FREEDOM OPTION $245

MEMORY EXPANSION OPTION.... $295 Send Check or Money Order to:

(MASS. RESIDENTS. PLEASE INCLUDE 9% TAX)

F.E.C. ltd.

P.O.Box 2368 • Weburn, MA. 01888 (817)944- 5328 ;"v^.;" !

IMODEL 1200 RS-232 Bi-DIRECTIONAL DATA SPLITTER

available in kit form

Model 1 200K gives Ihe terminal Of microprocessor user a second interlace for a printer, plotter, cassette or tape drive. It operates at any speed & isolates the two output devices from each other, while providing 2 RS 232 interfaces from the terminal or microprocessor

The kit consists of 3 RS-232 connectors, printed circuit board, all necessary components, enclosure, mounting ttardware & assembly instructions $69.00

write or call

TERIMINAL DATA CORP. 11878 Coakley Cir. Rockville, MD 20852 (301) 881-7655

Circle 403 on inquiry card.

DISK DRIVES

REMEX

Compatible with IBM and Shugart. Double sided. Double Deiisiiv

1600 KBvtes.

RFD4000 S595

Double Sided, Double Density

800K Bytes

RFD2000 $395

For fast delivery, send certified checks, money orders or call to arrange direct bank wire transfers. Personal or company checks require two weeks to clear. California Res. add 6% sales tax. Minimum shipping charge $ 10.00. N o C. O. D. Electronic Equipment Unlimited 3845 Birch Street Newport Beach, CA 92660

PH: (714) 540-5231 Pricing and availability subject to change without notice.

FOR INTERFACING TO: sensors, transducers, analog signals, solenoids, relays, lamps, pumps, AC motors, DC motors, stepper motors, keyboards, displays,488 GPIB.

ADDITIONAL FEATURES: 6800 MRU, counter/limer.toll safe battery bock up

WIKTI^K

Wintek Corp. 1801 South Street LarayeHe. IN <17904 317-742-8428

Circle 436 on Inquiry card.

Circle 447 on Inquiry card.

Circle 148 on Inquiry card.

NEED A LETTER QUALITY PRINTER BUT DON'T WANT TO PAY THE PRICE?

Then American Business Computers Has Just The Printer For You!

\umi rilc-r/umtsbK.i dear ciifiivs iisiiiti ti 'Xhcbamcler uiieet.

Illmxiuces /.ifiprtntahlenflumns, TljvStaniritifr ticcftmmndtiles

The Starwriter Daisy Wheel Printer is designed to fill a distinct gap in the peripheral marketplace. A speed of 25 cps and its low price make it the ideal choice for today's systems designer interested in achieving superior price/performance ratios.

Incorporating the latest LSI technology, the Starwriter is built by one of the world's most respected computer peripheral manufacturers. The printer is furnished complete and ready-to-use, requiring no changes in hardware or software. Starwriter offers an industry standard parallel interface, as well as RS232-C interface. Total plug compatibility and a wide variety of interface matching capabilities help lower the system integration costs for OEMs and end-users.

Using a 96-character wheel, the Starwriter produces letter-quality printing on 3 sharp copies with tip to 136 columns. Starwriter offers the highest degree of vertical and horizontal positioning, resulting in the most precise character placement in the industry. The easy-to-«hange character wheel also makes our printer a perfect choice for international applications. Compatible with sheet feeders, starwriter accommodates paper widths to 381 mm (15") and uses industry standard ribbon cartridges.

Along with a self-test capability and a programmable VFU (Vertical Format Unit), Starwriter furnishes the operator with all desirable status functions, commands and program selectable switches. Panel lamps indicate the current Paper, Select and Power status.

The easy plug-in compatibility of Starwriter and its outstanding print performance makes the Starwriter perfect for TRS-80*, Apple*, and S-1(X) users.

Starwriter is backed up by a one-year warranty (3 months on parts and labor, 9 succeeding months on parts) and is further supported by a strong, fully trained and technically proficient service organization. The Starwriter is available for immediate shipment in any quantity desired. For more information, call American Business Computer, 118 So. Mill Street, Pryor, Oklahoma 74361; Telephone 918-825-4844.

*TM of Tandy Corp

♦TM of Apple Computer Corp.

AMERICAN BUSINESS COMPUTERS

118 So. Mill Street

Pryor, Oklahoma 74361 Telephone 918-825-4844

Dealer Inquiries Invited

Circle 17 on Inquiry card.

BYTE May 1981 485

FOR

APPLE II

-COMPUTER COOLER

' ProtetT youp computer frof*» keot 1 oaJt cauteef by stajnaoT oir buildup ^lUhin fk< chants.

' Uiitivas lOO CFM fan ta Remove htctt suctioN.

Prtver.t» air <loui f ro»i 4ir«<.tL^ hif-ting my wmpoo«nt.

As n tepai-«te untt^ vtbrfttioN will b« minimi-xacJ > ' Keep your ayslem J*«n hf i^movinj ^Atst*.

Pritt... . * CS."

■NUMERICAL ANALYSIS PROGRAMS

'Quadrature and Sl,v,p60H Integration. ' Le(f«njrc PolYnom:ols . . . . ^otal packag. priceltSO.** SOFTWARE TECHNOLOGY -t-.,ms

B0X35 ■<-..! -n..„ o,J.,

SAUNDERSTOWN, Rl 02874 SilT.* .i"

1101) tS1-Z83l •'•l^-c « r«5iiT«r«d traJ.marlt »( Apple Computer Co., #• fBK s^item

Circle 375 on Inquiry card.

STEPPER MOTOR/ DRIVER BOARD

Interface your computer to the REAL world Indispensable for Robotics Mani^ control applications Each pulse from your computer steps the motor 7.5"

Features:

• North American Philips K82701-P2 type Stepoer motor

• SAA 1027 Stepper motor control I.C.

• Optically isolated

• 12 VDC operation

• All [.C.'s socketed

• Computer controls direction of rotation, 7,5* per step

PRICE

Complete DRIVER ASSEMBLY, incl. all I.C. 5, assembled and tested (does not irK:lude motor) $39.95 STEPPER MOTOR $2a95 SAA 1027 Driver chip only $16.50 Data, schematics are included Terms: Check or money order U.S. funds only. Add 2% (or shippirtg and hamflins. (N.Y. stale reudents add 7% saiec (ax) Inrnwdate ddnwiy finmsloch. AO

items guaranteed.

PO Box 56

Bellporc, New York 11713 (516) 286-2144

Double Side Disk Drives

Disk Drive Subsystem with Dual Double Side Drives, Power Supply and Cable. Total Capacity 2,4 M-Byte. Fully Assembled and Tested.

Only tl

1. Table Top Version $1,695.00

2. Rack Mount Version 1.695.00

3. Pair of Slides with Attachment

for Rackmount 35.00

4. S100 Disk Controller (handles single & double density in 256, 512 & 1024 byte sectors, single & double side) 350.00

5. Double Side Disk Drives (1.2 mb) , , ,. 535.00 (Qume DT/fl)

Call Now (408)496-6910

OSM Computer Corporation

2364 Walsh Avenue Santa Clara, CA 95051

Circle 306 on Inquiry card.

AFFORDABLE

Here at KLOFOX , affordable Is not a motto , it's a way of doing buslnessi Prices start at $l695'00i for a single 8"

drive system.

All systems feature a single board Z-80 CPU ( NO BUSS HEADACHES ), runs CP/H*2.2 ( BIOS INCLLTOED ), reliable SD recording, 6UK bytes of RAM, four channel CTC , and either an 80 x 24 full-featured, video Interface or a two channel serial Interface. PLUS a six month full warranty'''.

OPTIONS 1

2 Channel parallel interface- add $29.95 Both serial & video Interface- add $95.95 Single to dual drive conversion kit with drive and necessary hardware- add $495«00 AH options may b(! innialled by customwr. KLOFOX PO BOX 93 SAN LUIS OBISPO. CA 93406 (805) 541-0384 CP/K is a tzademai^ of Digital RiBsearch. *Only 90 days on drives.

COLOR VIDEO MONITORS RGB AND COMPOSITE VIDEO

•TC-700 13" color video monitor/receiver, NTSC composite video, $399.00 TC-900, 19", $595.00. Use with Apple 11 and III and

other computers.

•CM-19RGB: 19" screen, 3 modes: RGB, Composite video, TV. $895.00. •Apple III RGB Interface: Converts RGB data from Apple 111 to produce 16 color display on RGB monitor. $129.00. •Hitachi Hl-Res RGB, 13" character display, 2000, 80 x 24, 5 x 7 dot matrix, TTL inputs. $1200.00.

•Sony TV to video monitor conversion itit, MCK 100: $13S.OO.

•OEM 13" and 19" RGB color monitors, immediate delivery, prices and specs, on request.

For additional information, contact:

P.O. Box 339 Warrington, Pa. 18976 (215) 343-3000

Circle 428 on inquiry card.

INDUSTRIAL CROSSMACROASSEMBLERS

written in FORTRAN IV

New. two-pass macro assemblers fof all popular micros can be run on any general-purpose computer with standard FORTRAN. Each assembler supports macros, conditional

assembly, and relocatable obiect code. All the original mnemonics and addressing modes, many assembler direclives, long error messages and more. Produces printed assembly listing, and obiecl code file.

PROGRAM NO.

FOR MACHINE

PKG. PRICE

MASM68E3

MC6B0OO

S500

MASM6809

MC6B09

400

MASM6B0S

MC6B05

400

MASM6B0I

MC6eoi

350

MASM6800

MC6B00

300

MASM6502

MCS65KX

37S

MASM80B5

aoso.'Boss

3S0

MASM1802

CDPI802

300

Pockagei includa dftloilod utvrt

manual, priniad lou

rcB tilling [wall

commanladl, tourca on magnetic

lapa.and IDM*i So

Iwora Support

Servka. Cord dackt alio avgilobl

■ . Pnalar mquirlai inv

tad

I DM

intelligent devkas of minnesoto

P.O. box 14S3B 613] 427-0787

Circle 22 on Inquiry card.

Circle 213: on Inquiry card.

Circle 199 on inquiry card.

PASCAL SOFTWARE

Business Application Programs:

Accounts Receivable $795

Accounts Payable $795

General Ledger $795

Payroll/Job Costing $795

Property Management $995

Engineering Application Programs Customized Installation on Request Supplied on single-density, softsectored, 8" floppy disks; require 48KRAM.

HELU CORPORATION

P.O. Box 596 AIEA, HI 96701 (808) 456-1189

WANTED:

APPLE, PET, TRS-80, CP/M

SOFTWARE

Westico is a publisher and distributor of professional software for microcomputers, if you have a new program ready for distribution or want yourexisting programs to reactt a larger market, contact

Phillip Woellhof, V.P. Ml<tg.

Westico, Inc.

25 Van Zant Street

Norwalk, CT 06855

(203)853-6880 To increase your profits, take advantage of Westico's worldwide promotion and distribution

WESTICO

The Software Exptess Service

Circle 181 on inquiry card.

A-D & D-A CONVERTER

Z80 MICROCOMPUTER

6522 APPLE II INTERFACE

JBE A-D & D-A Converter can be used with any system tiaving parallel ports

• Interfaces with JBE Parallel I/O Card

• D-A conversion time — 5 /us • A-D conversion time — 20/us • Uses JBE SV power supply • Parallel inputs & outputs include 8 data bits, strobe lines & latches • Analog inputs & outputs are medium impedance 0 to 5 volt range.

79-287 WK^- $79.95

Bare Board $39.95 If Kit $59.95

This control cqm^Ber has: bytes RAM (tug^Hs) • 204S EPROM (2Z|^HK orte^e (compjg^i^^fnterfaces with JBE Solid«raTeSwitches & A-D & D-A Converter • Uses JBE §V power supply • 2716 EPROM avaiable separately (2716 can be prMpirnmed with an Apple 11 & JBE EI=JKM Programmer & Parallel Interfag^feSO pin connefctor included in kit. 80-153 Bare Bi

Your your

120VAC appliances up to 720 watts (6 amps at 120VAC). Input 3 to 15VDC • 2-14MA TTL compatible • Isolation — 1500V • Non zero crossing • Comes in 1 or 4 ctiannei version • includes doc. for interfacing w/ith Dimmer Control.

79-282-1 ASSM. $13.95

Bare Board $6.95 Kit $10.95

79-282-4 ASSM. $49.95

Bare Board $24.95 Kit $39.95

APPLE II DISPLAY BOARD

JBE is announcing a single board dedicate^, cofnputer designed for control funetlons. It features: • A Z80 Microprocessor software compatible with the Z80, 8080 & 8085 Microprocessors • Uses a Z80 PIG chip for I/O which has 2 independent 8 bit bidirectional peripheral interface ports with handshake & data transfer control • Uses one 2716 EPROM (2K) & twb|tt4 RAM memories (IK) • Single 5Vj| """"^ supply at 300MA req. • Clock frfii is 2MHz, RC controlled • Board with complete doc. • 50 pMoonn included '2716 sepa^

)0.2|M|^^Pi^~ ASSM. $129, Bar^Bn^.95 Kit $119.!

PRINTER INTERFACE

JBE Parafmi Printer Interface Inteffaoes your Apple 11* to Centronics* compatible printers. This 3" x 4" board features: on board ROM compatible with Integer Basic, Apptesoft® and Pascal" • Has one 6 bit parallel latched output port with selectable positive or negative strobe and one bit Input selectable for Ready or Ready • Cable and Connectors available separately.

80-297 ASSM.$79.9$

Kit $68.95

4 ft. Std. Dip Jumpers 16 pin $ 4.25 Champ Connector $ 9-95

POWER SUPPUES

fall tfansformers for against short clrj (reiakdown. $ VOLT POWER SUI Rated at 5V 500MA • Operati?SBE A-D & D-A Converter, Z80 & 6502 Microcomputers, 8085'^^HHH^Rmputers. 80-180 ASSM. $20.95

Bare Board $8.95 Kit $16.9S

± 12 VOLT POWER SUPPLY Rated at ± 12V120MA • Can be used as a single 24V pov\rer supply • Ideally suited to OP-AMP experiments.

80-161

Bare Board $8.95

ASSM. $22.95 Kit $18.95

80-144

Bare Board $25.95

ASSM. $49.95 Kit $42.95

• Has run-stop, single step switch • Has 16 address LEDs, 8 data LEDs & 1 RDY LED

• All lines are buffered.

ICS

6502 6522 Z80

Z80 PIG 2716 5V

$9.95 $9.95 $9.95 $9.95 $14.95

• Interfaces printers, synthesizers, keyboards, JBE A-D & D-A Converter,& Solid State Switches • Has handshaking logic, two 6522 VIAs & a 74LS74 for timing. Inputs & outputs are TTL compatible.

79 295 ASSM. $69.95

B a re Board $39.95 Kit $59.95

2716 EPROM PROGRAMMER

JBE 2716 EPROM Programmer was designed ^to program 5V 2716 EPROMS II imr\\

Terfaces t^^^Vf^le II using Srallel I/O Card & fSfn ribbon cable connectors • Art' LED Indicates wheri power is being applied to the EPROM • A textool zero insertion force socket is used for the EPROM • Comes with complete doc. for writing and reading in the Apple II or Apple II -i- • Cables available separately.

80-244

Bare Board $24.95

ASSM. $49.95 Kit $39.95

BARE BOARDS

APPLE II EXTENDER BOARD

SVz" X 2Vz". Price includes 50 pin Apple Connector.

80-143 $12.95

8085 3 CHIP SYSTEM

State-of-the-art system using §0,8085, 8156 & either an 8355 a||8755

• Instruction set 100% upw^Hcompatible with 8080A.

2i(d,.,^^^^^^^W4.95

item

using an 8088 CPU, 8284, 8155, 8755A & an 8185.

Bare Board $29.95

CRT CONTROLLER This intelligent CRT Controller is based on an 8085A Microprocessor & an 8275 Integrated CRT Controller. It features: • 25 lines, 80 characters/line

• 5x7 dot matrix • Upper case only

• Two 2716s • Serial interface RS232 & TTL • Baud rates of 110, 150, 300, 600, 1200, 2400, 4800 & 9600

• Keyboard scanning system • Req's. unencoded keyboard •Uses -I-5V & ± 12V power supplies.

Bare Board $39.95

50 pin connector STD. Dip Jumpers 16 Pin, 2 ft.

$5.95 $4.25

tJoHis^ Bell Eivgiiveeriivg

ALL PRODUCTS ARE AVAILABLE FROM JOHN BELL ENQINEERINQ • P.O. BOX 338 REDWOOD CITY, CA 94064 • ADD 6% SALES TAX IN CALIFORNIA • ADD 5% SHIPPING & HANDLING

(415)367-1137

visa]

FLOPPY DISKS

8'' & 51/4"

OPUS-$26.00/Boxofio 3M-$32.00/b ox or 10 IVirin PO Box 5059

incs -^^M

(203)877-3610

We carry a full line of computer supplies

Send for free catalog.

VISA- MASTERCHARGE-CHECK

Circle 267 on inquiry card.

ONE BOARD CP/M SYSTEM!

only $750 Assm., Tested & Burned-In for one week

Features:

• 8'/> by 12 inches

• 10 MHZ 8085 CPU

• 64K RAM

• 3 RS-232 channels

• 8272 Floppy Disk Controller

• Handles Single/Double Density

• One to Four Drives. 801R or 860R.

Uocumt'nLation $15, CP/M Floppy Disk Operating System SISO Check or Money Order

G

autocontroll

744 Westline Industrial Drive St. Louis. MO 63141 (3141 432-1313

Circle 37 on inquiry card.

MULTIPLE TERMINALS WITH CP/M®!

Uwu: Comijutei's NEW Mo(l(;l 100 Transjciion (^.iLiliipl'-'xt-T lets v^'U consirucl CP'M "-' l);)seiJ, mult I iL'Miiinal, tr,insaction orii;m(.'(f apiilicaiions without rt;(]ulring iKKliiional system memorv, surial interfaces, or a multiuser opera ling system i

The Mo(Jel 100 connects lo your computer in place of vour existiny RS 232 console terminal. Up lo seven (71 RS 232 terminal devices can then be connected to the Model 100. When tlie computer is busy, the Model 100 buffers all terminal input data until the application program asks for ii.

NO CP/M® mods, hardware mods, nor assembly language code is required. Applications can be written in high-level languages. Loaded with features! S1495. quantity one, F.0.8. Costa Mesa, CA. Limited manufacturer's warranty. For more information, call or write:

EASTERN U.S. AND FOREIGN:

Wright Marketing Company, Ltd. 19104 Rhodes Way

Gaithersburg, MO 20760 (301) 840-1928

WESTERN U.S.:

Irvine Computer Gorporalion (mfgr.)

3001 Red Hill Avenue, 6-103

Costa Mesa, CA 92626 (714) 557-5292

CP/M® is a registered trademark of Digital Research.

LOW PRICES

American Express, MasterCard & VISA accepted. Checks require time to clear, CA add 6% tax. All add 3% for shipping. We carry most all brands, micros, terminals, printers, software and accessories.

SP ELECTRONICS

P.O. Box 8265 Sacramento. CA 95818

(916) 442-2323

Clrcle-383 on Inquiry card.

Having trouble earning to use your coinputer?

rReference manuals don't teach. Most BASIC texts don't cover specific personal computers.

TIS solves these problems with step-by-step books tailored for your machine.

For PET/CBM

Understanding Your PET/CBM $16 95

Vol 1: Basic Programming

PET Graphics S 6,95

For OSI CIP/C4P

Understanding Your C1P/C4P $ 9.95

A Workbook of BASIC Exercises

Money Back Guarantee. VISA/MC accepted.

All prices Include UPS or 1st Class postage.

TIS. Dept B Box 921

Los Alamos, NM 87544

Circle 414 on inquiry card.

S-100 6809^

controls floppy ^

III

• Control^ 3 Mini Floppy DfivM

• Serial RS-232C port with 14 baud rates

• Two parallel ports

• 16 I/O decoded addreti llms

• 24K bytQi of EPROM spaca, or 12 KbytM

of RAM space

• Accept all JEDEC pin-out Byte-Wide

memory ICs

• Multi-Vendor software adaptable

• Industry, Busineu, Home and Univertitv un

• Assembled and tested S395.00. 60 day delivery

• Checks or CCD. orders accepted

• DEALER INQUIRIES INVITED

LOGICAL DEVICES. INC. 781 W. Oikland Park Blvd. Ft, Ijudndsle^ FiB. 33311 Tel: ^05)5e&-8103

Know The Reasons Why The FORCE-80 is your "Best Buy."

FORCE-SO The computer protector

• Power dropout protection

• Suppresses transient voltages

• Suppresses RFI

• Disc protection

• Factory warranty

• Satisfaction guaranteed

• Direct from factory

FORCE-80

Only $121.50 plus $5.00 shipping & tiandling Check, Mastercharge, Visa accepted (5% discount for cash) No CCO.'s please ^Jjjs^

P&S Electronics, Inc.

P.O. Box 23014 Dept. B Nashville, TN 37202

Allow 6-8 weeks for delivery

Circle 307 on Inquiry card.

* APPLE II USER'S *

Put iJDur proarsiks to work eamirtS for uou todsul Ue want ia »irket aaur best prodrans ba off»rina them

to user's through our p.-;i>3ndlna SOFiyARE LIBRARY....

Uf?

tool' 1

atio

EDUCATIONAL. ME:iiir;AL. LCGfll..

BUSINESS. ACCOUNTING. STATISTICAL. ENGINEERING* HOME* UTILITY. and GAMES I

Please drop us a line with dstsils nf HouT pro^framsi In reiurnt ue will send uau the specifics of our Biardetinfl rrocess.

Tf ynn uuMlrl 1 i V f to bH On OUT RorTUAicr I lEiRARr CATALOG mailins list then check the reader Evrvice nurjihpr bploui... (DEALER INQUIRIES INUITEI'l . . .

WRITE ro:

HCU3 ENTERPRISES P.O. BOX 510 GOUrHBURY. TT.

.'ir cciDc odiea

APPI f II IS ttie Ir^iJenidf k oC (!it^

Circle 179 on inquiry card.

DOUBLE YOUR LA36 DECWRITER S SPEED TO 60 CPS

The ACCELEWRITEB converter enables you to convert the LA36 Oecwrlter from 10/15/30 to 10/30/60 CPS.

Utilizes Decwriter's own built-in 60 CPS.

speed Plugs into logic board Compatible with Decwnter option boards Decwriter reconverts to "stock" in

seconds Thousands sold In use lor over 3 years Full one-year warranty S115 includes shipping

Brochure sent promptly at your request.

Write or call us.

LARKS ELECTRONICS & DATA

P.O. Box 22, Skokie, IL 60077 (312) 677-6080

Circle 165 on inquiry card. C^lrole 334 on Inquiry card.

Circle 215 on Inquiry card.

r

16K Memory 8/$19.95

4116 200ns . ^ NEC Mostek

ALL MERCHANDISE 100% GUARANTEED! CALL US FOR VOLUME QUOTES

LS SERIES

74LS00

74LS01

74LS02

74LS03

74LS04

74LS05

74LS08

74LS09

74LS10

74LS11

74LS12

74LS13

74LS14

74LS15

74LS20

74LS21

74LS22

74LS26

74LS27

74LS28

74LS30

74LS32

74LS33

74LS37

74LS38

74LS40

74LS42

74LS47

74LS48

74LS51

74LS54

74LS55

74LS73

74LS74

74LS75

74LS76

74LS78

74LS83

74LS85

74LS86

74LS90

74LS92

74LS93

74LS95

74LS96

74LS107

74LS109

74LS112

74LS113

74LS114

74LSI22

74LSI 23

74LS134

74LS126

74LS126

74LS132

74LS136

74LS138

74LS139

7415145

74LS148

74LS151

32

7/11 c;i f^fi

1 19

28

7/11 Q1

95

38

74LS157

79

74 LS158

35

94

28

74LS161

99

38

74LS162

99

38

7/11 1

99

32

74 LS164

99

29

7/11 <^ 1

99

29

741 mRfi

2 40

38

7/11 Q1fiH r 4LO1DO

1 79

99

1 79

35

74LS170

1 89

7^|"qi 7^

82

7 II Q1 7^

1/1

1 nQ

74LS181

2 19

1A1 Q 1 Qn

1 15

1 31

74LS192

QR

74LS194

1 80

78

7/11

1 39

39

7/11 Q1QR

82

'or

74LS197

82

.79

78

7dl <59dn

1 89

78

74LS241

1 gg

35

74LS242

1 89

35

74LS243

1 89

.32

7/11 /I

74LS245

2 89

48

74LS251

1 32

58

89

50

74LS257

89

59

7dl ^i^'^R

89

90

7AI

2 89

1 23

68

45

7dl

68

70

74LS273

1 69

82

74LS275

3 39

71

74LS279

^59

1.11

74LS283

1.03

.86

74LS290

1.25

,43

74LS293

1.89

.49

74LS295

1.09

,48

74LS298

1.24

.48

74LS352

1,59

.55

74LS353

1 59

.55

74LS363

1.39

.99

74LS365

.99

2.99

74LS366

.99

.99

74LS367

,99

.88

74LS368

.99

.69

74LS373

1.85

.58

74LS374

1.81

.79

74LS377

1.48

.79

74LS385

1.90

1.19

74LS386

.65

1,39

74LS390

1.90

.79

74LS393

1.90

79

7.11.839'"^

1 69

SPRING MEMORY SALE

RAMS

lOOpCS

EPROMS

2101

(450ns)

2.49

2.29

lOOpcs

2102-1

(450ns)

.99

.95

1702

( 1us)

4.95

4.75

21L02-1

(450ns)

1.29

1.15

2708

(450ns)

4.95

4.75

2111

(450ns)

2.99

2.49

2758(5v)

(450ns)

9.95

Call

2112

(4S0ns)

2.99

2.79

2716(5v)

(450ns)

7.95

6.95

2114

(450ns)

2.95

2.85

2716-1 (5V)

(350ns)

12.95

10.95

2114L-2

(200ns)

8/29.95

3.10

TMS2516

(450ns)

9.95

9.50

2114L-3

(?00ns)

8/24.95

2.95

TMS2716

(450ns)

9.95

8.95

4027

(250ns)

4.95

3.95

2732

(450ns)

29.95

Call

4116-15

(150ns)

8/21.95

2.65

TMS2532

(450ns)

21.95

Call

4116-20

(200ns)

8/19.95

2.35

TMS25L32

(450ns)

29.95

Call

4116-30

(300ns)

8/18.99

2.29

TMS2564

(500ns) 179.95

Call

NEED YOUR ORDER SHIPPED TODAY?

THEN CALL TOLL FREE

800-538-5000

IN CALIF.

800-662-6233

BEFORE YOU BUY, CALL US. WE WILL BEAT ANYONE'S PRICES

Z80

Z8t)

9.95

Z80A

12.95

zaocTC

7.65

Z80DMA

18,00

Z80-PIO

7.60

Z80-SIO/2

27.50

z80-siora

20.50

MISC.

1771-B01 3242

AY5-1013

8T26

8T28

8T97

iT98

24.95 9.95 4.99 2.49

2.49

1.59

1.69

8080

8080A

3.96

8086A

12,95

8212

2.75

8214

5.25

8216

2.76

8224

2,95

8226

3,49

8228

4.95

8238

5,50

8251

6.95

8253

12.95

8255

6,50

8267

16.95

8259

14.95

8275

49.95

8279

15.95

T.V. CIRCUITS

MC1330

MC1350

MC1358

LM380

LM565

LM741

LM1310

LM1800

I. M 1889

1,89 1,29 1,79 1.29 ,99 ,29 1,90 1.! 2.49

7400 SERIES

7400

.19

7450

.19

74123

.59

7402

.19

7472

.29

74151

.69

7404

.24

7473

.34

74153

.59

7406

.29

7474

.35

74164

1.49

7407

.29

7475

.49

74156

.69

7408

.24

7476

.35

74157

.69

7410

.19

7483

.65

74161

.79

7420

.19

7486

.35

74163

.89

7430

.19

7490

.49

74164

.89

7432

.29

7491

.69

74173

1.39

7440

,19

7492

.59

74174

.89

7442

.49

7493

.49

74175

.89

7445

.69

7496

.74

74176

.89

7446

.69

74100

1,19

74192

.79

7447

,59

74107

.34

74193

,79

7448

,69

74121

.34

74196

,79

74S00 SERIES

74S00 ,50 74S124

74S02 .50 74S174

74S04 .50 74S188

74S08 .50 74S195

74S37 .55 74S240

74S74 ,80 74S260

74S113.79 74S287

3.95 74S288 4.75 1.49 74S387 5.75 4.75 74S471 18.75

1.96 74S472 18.75 2,95 74S474 19,95 , 1.80 74S570 7.80 4,75 74S571 7.80

IC SOCKETS I VOLTAGE REG's ItRANsistors

8 pin ST 10/1.29

14 pin ST 10/1.29

16 pin ST 10/1.29

18 pin ST 10/1,29

20 pin ST 10/1,29

22 pin ST 10/1.29

24 pin ST 10/1.29

28 pin ST 10/1,29

40 pin ST 10/1.29 ST = SOLDERTAIL

Spin WW 14 pin WW 16 pin WW 18pin WW 20 pin WW 22 pin WW 24 pin WW 28 pin WW 40 pin WW

.69 ,69 ,69 ,99 1.09 1.39 1.49 1.69 1,9

WW = WIREWRAP

4K STATIC RAM SPECIAL

MOTOROLA

PART #MCM66L41C,20 REPLACEMENT FOR TMS4044,20 4096x1 THESE ARE CERAI^IC 200ns LOW POWER RAMS IN A STANDARD

18 PtN DIP VERY LIMITED SUPPLY. THEY WON T LAST LONG AT THIS PRICE.

3".. 16/59"

7805T .89

7812T .89

7815T .99

7824T .99

7805K 1.39

7812K 1.39

78L05 .69

78L12 ,69

78L15 ,69

7905T ,99

7912T ,99

7915T 1,19

7924T 1.19

7905K 1.49

7912K 1.49

79L05 .79

79L12 .79

79L15 .79

LINEAR

LM301V

LM308V

LM309K

LM311v

LM317I

LM318V

LM323i<

LM324

LM339

LM377

LM380

LM555V

.34 .98 1.49 .64 2.29 1.49 4,95 .69 ,99 2.29 1.29 .39

LM556 LM565 LM566V LM567V LM723 LM733 LM741V LM747 LM748V LM1310 1,90 LM1414 1,59 LM1458V ,69

V = H pii

.69 ,99 1.49 1,29 .49 .98 .29 .79 .69

LM1488 LM1489 LM1800 LM1S89 LM3900 75451V MCI 330v 1,89 MC1350v1,29 MC1358 1.79

1,39 1,39 1,99 2.49 .59 ,39

I2N2222 10/1,00 100/8,99

I2N3904 10/1,00 100/8,99

I2N3906 10/1.00 100/8,99

I2N3055 ,79 10/6,99]

LEDS

Jumbo Red 10/1.00 Jumbo Green 6/1.00 Jumbo Yellow 6/1.00 5082-7760 ,43'CC ,79 MAN74.3CC .79 MAN72.3"CA .99

DIP SWITCHES

4 position

5 position

6 position

7 position

8 position

.99 1.02 1.06 1,09 1,14

JDR MICRODEVICES, INC. 1101 South Winchester Blvd. San Jose, California 95128 800-538-5000 408-247-4B52

TERMS: Include $2,00 lor shipping, $10,00 minimum order. Send BASE lor complete catalog. Bay Area Residents add 6V>% sales tax Calif, Residents add 6% sales tax. We reserve tlie rigtit to limit quantities and substitute manufacturer. Prices subject to cliange without notice. Foreign orders add suff, postage.

Circle 209 on Inquiry card.

BYTE May 1981 489

ISIPCRLEHCRJ

Is For

SuperBraln'^ People!

Now, owners and operators of Inlertec SuperBrain computers around the world have a special newsletter to call theirown! Superletter is packed with important technical news, accessory ideas, and CP/M software designs for the SuperBrain. Regular features includeTechnical Corner, Q & A Forum, Interteo Factoty News, Guest Interview, and Super Classifieds. Forsubscriptlon infoand ad rates,contact:

SIPERLETTER

Abrams Creative Services

P.O. Box 3121 Beverly Hills, CA 90212 (213)277-2410

Circle 3 on inquiry card.

TWX-LINK

TWX-LINK is a complete software package vtrhich interfaces your microcomputer to tile Western Union TWX

network.

Using an FCC approved direct connect modem, TWX-LINK allows your computer to act as a TWX terminal for both incoming and outgoing messages.

TWX-LINK constantly monitors your TWX line. Incoming messages are automatically received, acknowledged, and written to disk storage.

TWX, TELEX, IWAILGRAMS, AND TELEGRAMS can all be created, edited, and sent from your computer by using TWX-LINK.

Call, wrrite, or TWX for more info: CAWTHON SCIENTIFIC GROUP 24224 IVlichigan Avenue Dearborn, Michigan 48124 PH: (313) 565-4000 TWX: 810-221-1265

Circle 63 on inquiry card.

THE COMPUTER OF THE FUTURE Bigger Vnan 8-blt, smaller than 32-blt; IEEE 696/S-100 compatibility and RS-232 I/O. Next Vear-lhe computer of ttie future witti user software will be tiere at S20,000. TODAY we can offer you ttie NUCLEUS of TOIvtORROW's computer for only

$2995

A package of IEEE standard boards AND the latest 16-blt software - O.S. and PASCAL

• DUAL CPUs - 8085 for current programs

- 8088 for 16-bit software

- without changing hardware

• 64K byte fast, reliable fiAM

• DfvIA Disk Controller

• Support board - clock, RS-232 port, etc.

ACT NOW-LIMITED QUANTITIES AVAILABLE AT $2,995 PRICE CALL or WRITE NOW FOR FULL DETAILS (213)454-2100

SYSTEM INTERFACE CONSULTANTS, INC, 17440 Revello. Pacific Palisades. CA 90272

computer systems established 1969

Circle 395 on inquiry card.

INVENTORY CONTROL SYSTEM

WITH PARTS EXPLOSION FOR FINISHED GOODS AND ASSEMBLIES Parts requirements forecasting & Pull Sheets Reorder Reports Economic Order Quantities 5000 Items per 8" disk AVAIUBLE FOR CROMEMCO, CP/M'^, AND OASIS OPERATING SYSTEMS

Hardware rtqulremtnts: 64k RAM. 132 Column printer.

Manual and 8" floppy disk $250.

Multi-level explosion version $499.

Job Costing $350.

Accounts Receivable. Accounts Payable. Order Entry, General Ledger Payroll and Mailing List programs also available.

FEITH SOFTWARE. INC.

204 MARVIN RD. ELKINS PARK, PA. 19117 (215) 782-8240

Circle 162 oil Inquiry card.

DIGITAL RF-LINK

MAXI MICRO

MAGNOLIAI

MICROSYSTEMS

S81S Ttiomdyke W. • Seattle. WA 98199 C208)SB5-7SB8 (8aa!426-S841

CP/M Is a tredemark of DIoitBl Ressanih.

Circle 226 on inquiry card,

APPLE OWNERS!

Combine your APPLE computer with our higti speed dual channel AID and controller boards to create your own:

DIGITAL STORAGE SCOPE

• Sample late DC to 3.5 Mhz.

• 1024 Sample Buffer Memory

• Pretrigger Viewing

• Dual or Single Channel Trace

• Trigger either channel

• Programmable Scale Select

All trace parameters are entered through l<eyboard to the onboard software included in PROM. High resolution graphics used to display

waveforms.

Price for two board system $495. California residents add 6% salestax.

RC ELECTRONICS, INC.

7265 Tuolumne Goleta, California 93117

18051 968-6614

Tl 820 KSR PACKAGE

NEW $1737

BRAND NEW IN BOX WITH 112 PAGE MANUAL

FULL (Tl Item «101) OPTION "PACKAQE": Dnin tornis controt. comprsufld & oxpandBd print, IS kty numeric pid, lull ASCII. We count mora than lOO user eelecMble oplloni & featuret. Tliii vlrluelly auurei competlbllily with your application.

PARTIAL LIST OP FEATURES

normal, compressed and atandird prts. (4 atytnj to 218 tiMmTUne; bidirectional: 1280 char, buller; V A H laU; T-W tractor fMtf; 8 t •

KEYBOARD: Full ASCII; 18 key rtum. pad: prog. CR ana B4TER heya; comroi panel with numeric display: aula rapW: N'keyrollow: pull-oul

oporalor'E rqlerence cerds, deep dllh keys.

QENERAL: Full blown R5-232. 110-9G00 baud. EIA & DC3/DC1 busy; Bell 103. 113. 302 & 212A modes. local/standCy/olt-line modes, nonvolalile OpliDn/loims/2t char prog answerback memory: parity select., 6' EIA cable; FOXA^DX/HDX w/reve'te channel

PRICINO: Usipricafo(lhtBcontlgurallonlBS242aOiU'prico,brandntw m original box. guaranleod working to Ml spMlftcationa. lITSf FOB Morris Plains. NJ. COD and cradH Cards on approval, NJ add saiM las.

Call or write lor lull speciFi cat ions

ELECTROVALUE INDUSTRIAL INC.

Pnon* reHrviueni and

»i/a«T-iiiT

TRS-80

MODIL I III

SPEECH

SOUND

CUSIOM SOUND t IS a ocrpmor controlled, ccirploj sound !^'lM.■r.1tor c^quble of throe tme iiustc as ucll a-: ■■lo'.-iil sound effects. Ttireo tone gi?nerjtf;r.i 0}ier<ite wit!) .1 "vhito" noise source and programiMp lolin? t-Liiitrul raniJ generator to areate d wialtJi of lioinid oftcctB, All control runcttons ate latched, allowing tlE CS board to operate uhile the piogran continueB, peniutting rontinuaus somd production ducirej program

The C3 toord oonts an a hit or as an as^itiled PC board. It ncods only 5vrc .it 200nvi, a forty ' r cable and a speaker

tfco tftits soy be oporated ^imilt<ux?< KIT

ASSEMBLED

-(49/ two for S85 -S58/ two for S98

OiSIOki SPfECH SYNIMESISIR :is a ptonene based speech synthesiser \Aich can generate higti quality, inflected huivtn like ^«ecti of wiliinited vocabulary, Ifcorty aix (iSnrw.Tfs allow tit cro.icion Of BDat any engllali hMd ,is .IS nviR)' mn-o«)liBh w>rds. tho wiit OOnas

iiid Linti icBtt-d and needs only a forty

inlo ujqj. port of Civ or EX/IWT. J20

double cable --t25 5VDC REGULATED POWER SUPPLY : fully ass^,i,!<i.

'ustom feripherals

i-f< upefcB for Afllvery

Circle 141 on Inquiry card^^

Circle 346 on Inquiry card.

Circle 108 on Inquiry card.

TRS-80 SERIAL I/O

• Can input into basic

• Can use LUST and LPRINT to output, or output continuously • RS-232 compatible • Can be used with or without the expansion bus • On board switch selectable baud races of 110.150,300, 600, 1S00, 3400, parity or no parity odd or even, 5 to 8 data bits, and 1 or 2 stop bits. O.T.R. line • Requires +5. -12 VDC • Board only $19.95 Part No. 8010, with parts $76.69 Part No. 801 OA. assembled $98.35 Part No, 8010 C. No connectors provided, see below.

m/RS-333 cwinuclor Pan No DB25P S6 00. with 9. S conducox cade $19 65 PwtNa.DBS9Pg

3' ribbon cable with attacHeflcwmector^tolit TRS-80 and our ser.al bunrtj S371D Part No 3CAIW0

VIDEO TERMINAL

16 lines, 64 columnsUpper and lower case

• 5x7 dot matrix • Serial RS-232 in and out

with TTL parallel keyboard input • On board baud rate generator 75. 110, 150, 300. 600, S. 1200 jumper selectable • Memory 1024 characters (7-21L02)

• Video processor chip SFF9B3B4 by Neculonic • Control characters tCR, LF, —1 -, ', i, non destructive cursor, CS, home, CL

• White characters on black background or vice-vepsa • Withi the addition of a keyboard, video monitor or TV set with TV interface Cpart no. 1G7A) and power supply this is a complete stand alone terminal • also S-100 compatible • requires + 16. S. -IB VDC at 100mA, and 8VDC at 1A Part No. 1000A . S23BA5 kit.

GAME PADDLES &SOUND FOR TRS-80

Includes: 2 game paddles, interface, software, speaker, power supply, full documentation including; schematics, theory of operation, and user guide; plus 2 games on cassette, Pong and Starship War $157.29 Complete Part No. 7922C

SERIAL/ PARALLEL INTERFACE

• Converts serial to parallel and parallel to serial • Low cost on board baud rate generator* 11Gto19.2K« Low power drain +5 volts and -12 volts required • TTL compatible • All characters contain a start bit, 5 to 8 data bits. 1 or 2 stop bits, and either odd or even parity. • All connections go to a 44 pin gold plated edge connector • Board only $11.95 Part No. 101, with parts $42.89 Part No. 101A, 44 pin edge connector S4.00 Part No. 44P

MODEM

• Type 103 •Full or half duplex • Works up to 300 baud • Originate or Answer • Serial TTL input and output • connect 8 n speaker and crystal mic. directly to board • Requires -1-5 volts •Board only $7.60 Part No. 109, with parts $29.95 Part No. 109A.

OPTD-ISOLATED PARALLEL INPUT BOARD FOR APPLE II

There are 8 inputs that can be driven from TTL logic or any 5 volt source. The circuit board can be plugged into any of the 8 sockets □f your Apple II. It has a IB pin socket for standard dip ribbon cable connection. Board only $15.85 Part No. 120. with parts SB9.95. Part No. 120A.

Tiliiiiiiiiiiilii

SUPER MODEM

Originate, RS-232 and 20 mA compa table. Full duplex, and half duplex, direct connect or acoustic coupled, on board powersupply.carrier detect light. DB25 plug. 300 BAUD, Type 103 compacable frequencies. Bare board Part No. 2000$21.89. Kit Part No. 2000A$133.80

8K EPROM SAVER

• Programs 2708's address relocation of each 4K of memory to any 4K boundary • Power on jump and reset jump option for "turnkey" systems and computers without a front panel

• Program saver software in 1 2708 EPROIVI $25. Bare board $45.59 including custom coil, board with parts but no EPROMS $164.69.

APPLE II SERIAL I/O INTERFACE

Baud rate is continuously adjustable from □ to 30,000 • Plugs into any peripheral connector • Low current drain. RS-232 input and output • On board switch selectable S to 8 data bits, 1 or 2 stop bits, and parity or no parity either odd or even • Jumper selectable address • SOFTWARE • Input and Output routine from monitor or BASIC to teletype or other serial printer • Program for using an Apple II for a video or an intelligent terminal. Also can output in correspondence code to interface with some selectrics. • Also watches DTR • Board only S14.95 Part No. 2. with parts $51.25 Part No. 2A, assembled $62.95 Part No. 2C

PARALLEL TRIAC OUTPUT BOARD FOR APPLE II

This board has 8 triacs capable of switching 110 volt 6 amp loads (660 watts per channel) or a total of 5280 watts. Board only $15.65 Part No. 210, with parts $119,95 Part No. 21 OA

APPLE II PROTOTYPING HOBBY/CARD

Part No, 7907

S21 95

RS-232/ZOmA INTERFACE

This board has two

passive, opto-isolated circuits. One converts RS-232 to 20mA, the other converts 20mA to RS232. All connections go to a 10 pin edge connector. Requires +12 and -12 volts. Board only $9.95, part no. 7901, with parts .S14.95 Part No. 7901A.

T.V. INTERFACE

• Converts video to AM modulated RF. Channels 2 or 3. So powerful almost no tuning is required. On board regulated power supply makes this extremely stable. Rated very highly in Doctor □obbs' Journal. Recommended by Apple • Power required is 12 volts AC C.T., or +5 volts DC • Board only $8.19 part No, 107, with parts $18.85 Part No. 107A

TAPE INTERFACE

• Converts a low cost tape recorder to a digital recorder • W/orks up to 1200 bauds Digital in and out are TTLserial • Output of board connects to mic. in of recorder • Earphone of recorder connects to input on board

• No coils • Requires +5 volts, low power drain • Board only S7.60 Part No. Ill, with parts$29.95Part No. 111A

RS-232/TTL INTERFACE

• Converts TTL to RS232, and converts RS232 to TTL • Two separate circuits • Requires -12 and +12 volts • All connections go to a 10 pin edge connector, kit $9.95 Part NQ232A10Rnedge connector S3.00 part No. 10P.

S-100 BUS ACTIVE TERMINATOR

Board only SI B.I 5 Part Wo, 900, with Darts S29.B9 Pn.-i Nfi ;l[)nA

SERIAL I/O

Four Serial I/O RS-232 ports. S-100 Bus, Software or jumper selectable

baud rate (110. 300. 600. 120D. 2400.4800.9BDa. 19.2K), on board Xtal baud rate generator. Addressing, switch selectable, Parity or no parity (odd or even) switch selectable, 1 or 2 stop bits, 5 to 8 bits/character. Board only $35.19 Part No. 7908. With parts (kit) SI 99.95. Part Nd. 790BA,

RS-232/TTY INTERFACE

"A^r iva Sao

This board has two active circuits, one converts RS-232 to 20 mA, the other converts 20 mA to RS-232. Requires +12 and -12 volts. $995 Part No. SODA Kit, A

FTo Order:

Send for FREE Catalog...a big self addressed envelope with 80<i; postage gets it fastest!

Mention part no., (description, an(d price. In USA siiipping paicd by us for onjers accompanieid by checl< or money order. We accept CCD. oriders (U.S. only) or a VISA or Master Charge no., expiration (date, signature ancJ phone no., shipping charges will be acJided. CA residents add 6.5°/o for tax. Outside USA add 1 5% for air mail postage an(j hanidling. Payment must be in U.S. dollars. Dealer inquiries invited. Prices subject to change wittiout notice

ORDER LINE: (408) 226-406'=

ELECXRONIC SYSTEMS ^^^'^^^ ^-^^ 2^^^^'

Circle ISO on Inquiry card.

BYTE May W81 491

7400

CMOS

74LS00

SN7400N

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69

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7.95

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.98

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2.75

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4 50

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29

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MODEL NO

DESCRIPTION

PRICE

9600A

Single Board Microcomputei

5495 00

9609

Advanced Single Bd CoTm (6809

595.00

9601

16 Slot Mother Board

175-00

960?

Card Cage

75.00

9603

8 Slot Mother Board

10000

9604

Power Supply

27500

9605

DC Inoul Powe' Supply

325 00

9610

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39 00

9611

Aritri Proc/MefJiory Module

495 00

9612

Buderet) UliMy Prolo Soara

49 00

9616

32K EPROM/RAM ModuJe

250 OO

9617

EPROM Programming Head

250 00

9620

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295 00

9622

Senni-Parallel I/O Module

325 00

9627

I6K Sialic RAM Module d70ns

395 00

9629

32K Slal-c RAM 450ns

695 00

9629A

32K Slaltc RAM 200ns

895 00

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Card Extender

66 00

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395 00

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395 00

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550 00

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27 5 00

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WITH ALL OPTIONS ACP PRICE $699.00 I

Om-on 'W Terminal Screen Butler |l920Cnar-| 55000 Ooiion -S' High Speed Paoer Advance A Graphics SO 00 On"on -r Tractor Feed SO 00

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750

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27.50

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32 r-:

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()t):j.M 'ii."' 1 8 Eprom (;art5/HD46b05 CRT Com liHrt / Color CRT 6B50ACIA. . 6B52 Serial Adapter 6860 Modem 6862 ModulBlor 6B71A rOMHiOSC. 6875 6 95

6880 Bus Driver 2 35

MC6B48e 19 95

68047 24 95

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2504V 1 49 2525 1 49

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2517V 1 49 2528 I 49

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2533 1 49

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1)520 PtA 662? Mull

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H2S23 6 9

82Si:)l 14 =

825137 14 9

74S387 B.E

74S471 . 12.a

74S472 12.9

74S370 - 14.9

74S571,... 149

NOTE: WE pnOQRAM PROMS

CHARACTER GEN.

M l-OOl (5V)Uooet .i;)-005 I5V1 Lower .13 ADM3 (5V1 Lower

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6 95

7 95 8.95 995

STATIC RAMS

21L02 2SOns I

2112-1 2101-1 2114L-250ni.|40dSl II 14L-4E0nt. (40451 4044 250 n«. 4044«a0n«. EMI*t42O0A EMM4402 AM09140/4I Altl 09130/31

379 3 es 3 55

2 9B 2 8a 2 65

2 90 2 70 25s

e 50 5 95 S 50

'95 725 G25

199F. 1S95 '63;

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418/4116 I6K(I6P<n) Sei □<8 4t6's 4l15BK|IGPin| 4050 4K . I it6P.ni 4060 4K . ' (22Pini 4096 4K > 1 KG P>nl 2104 4K . 1 lldRnJ 4027 4K > I 116 Pml

5261

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1 10

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140

1 10 1 20 148 1 G9

189

ZERO INSERTION FORCE

ieP>n S550 24Pin S7S0 40Pin %\Q2b

LED READOUTS

Cdtm CltfitOf

f'H»07lS10l 500 fW Com. Anay PID508 500 Bm Co-w. 11

FVDSSO bm Gift" Cw" Cjnnip

i«oa;-73

t<'50fl?./3

WN30S2 1UN3063

WhlSOM )UH30S'

3DD RM Ccmm Am* Right OP

300 RU Conn AnoOc Idl OP

»0 m DmUM. CiMtti op

300 HM Cam CaMi RdM DP

300 Gntn Cd™ *n* tini DP

300 Gtcn Cam.AoM'.Ufl 0»

300 G«n fMim'&^mW

300 Gitdi Cttim Citltdl MM OP

3DD rtliM Canm MM *</*DP

300 rdHw Cam «nalc Icfi OP

m lOtn. Ovtiim. C» icfi OP

IC SPECIAL PURCHASE

ICL 82' 1 voliayc Releiencf LM 1B50N Gtound Fault IC LM 2900N Quad Amplidei Lt^ 2917N Frea lo Vo" Cpnv AY-3-3550 4>, Oigi! OI-IM AY-5-3507 aOMHi DVM

MEM 4953 Mostel Smoke Deiector 27S08 32 ' 8 Prom (IM.S600I G1 I5M 6 criannel li^oslel ULN 2003A 7 channel Driver

2101AL-4

MCM 14505 64 bl Sialic Ram MOC 1003 (4N28) OdIo Coupler

SPX33 Opto Coupler,

IN 5045 CMOS Swilch DBST

VA 3045 Trans Array

TH 1402AUART .

MR 1007 Dyn, Mem. Shift Reg

5736 Gate. Con. Circuit

5763 Gale. Con. CircuH

5318TVCh.Disp. Circuit

eoBOAaatcpu

62821 32 X 2 Static RAM

a/oocjaatA/D

2758 5V-270a ERTOM

MM5280/VPD 411/C2 107/TMS 4060/

4Kx1 Oynamic 22 Pin RAM

6604/VPD 414/4027/2660/MK 4096/

4Ki1 Dynamic 16 Pin

Ne« National Oocli Tip MM 58167

Real Time

7520/25 50 LM 387

MB6'14a9 2,'1 99 LM 3302 MK50'4Calc 3.'i 99 LM 4556 LM323K 4 96 RC 4136

t/C1372 a 96 RC 4131

MM5298-4A/a 2.9£

6 9S 3/1 OC 3/1 OC .4 50 . 1 25 1 95 ..395 2/1 99 ..1.95 ..4,50 .4.95 2/1.99

' 25

LM3B0 1-25

COM 5027 COM 5037 DAClOO

Avbiai 6A iHhj i5Vi

IMS I.Ot 1 16V 1 J\/i

IM6402

IM6403

2350 USRI

<57lB Astias

SALK m«nB.....

MC144t1

VERBATIM DISKETTES

100% CERTIFIED EnROR-FREEI

• 3S mm. mni imm sikgiE'Iided S".

ypi DEscHiPTiON '■net mx

FLOPPY DISK I/O

I77101 S~a Mimnoow 24,95

uP(1372 Nec Floppy 49.95

l7St Dual Floppy 29.95

1791-01 Dual Floppy , . 36.95 uPd 765 Ropoy .49.95

A/D CONVERTERS

13 50 22 00 '3 50

S700 8 bri Binary

B701 8703 8

,1 TS

9400 Volt IC 6750 3'jOigil eCD I408L6 6Dit 1408LB B Oil DACOl 0 to A DACOfl DAC 100

13 95 3.95 595 5.95 9 95

1595

TV CHIPS/SOUND

AV3860O-I 6 Games WW AVSaSl 5 Color Convener AY3B6031 RoadraceGame AY38606-1 WipeourGame AV38607-1 ShoQling Galler, AY3a910 Sound Generalo' SN76477TI Sound Generalor MM6320/21 TV Synch Gen MMS369 Prescaler LMia89RF Modulator MM57100 NSC Color TV lkflM57l04 Clock Gen

RF W MSR ModL

12 95 395 995 395 395 695 3 75 8 95 29 95

WAVEFORM GEN.

8038 Function Gen 3.95

MC4024VCO 2S5

LM566VCO , . 1,95

XR2206 Funclion Generaior ,, 5.25

SHIFT REGISTERS

MM500H Dii;it25 50 MM5056N Dual 256 2 95

MMS060N Dual 128 2.95 25t0AOualtO0 196 2847 Quad 80-. 4.95 3341 Dual 80 «.S5 3351 40 > 9 FIFO 3357 Quad 80 9403 16 . 4 FIFO 9408 10 Bit Sequencer 3347

6 95 24 95 9 95 5 95

CIS DIPSWITCHES

CTS206-2 1 75 CTS206-7

CTS20fr4 t 75 CTS206-8

CTS206-5 1 75 CTS206-9

CTS205-6 1 75 CTS206

0 1 95

3.75

CONNECTORS (GOLD)

DB25P1RS232I DB25S Female

Hood.. 1.2S

Sei w/Hood. Sate.. , S7.50

22/44 W/W. S^. KIM 2.95

43/86 WAV. S/T, MOT . 6.50

50/1COS-100 Connector wAv 4.95

50/100 S-1W Connector s/i . 3.95

NAKED PC

. S34,95 34,95 34.95 29.95 39.95 2495 30.00 . 34 95 .. 34 95 .. 27.95

S-IOO Sound Board, Z-BOCPU/(lthaca)., .

8080A CPU

16K State RAM (211' 32KSlate RAM (211' SK Eprom (2708) .. 1702 Eprom Board. 2708/2716 Eprom Realtime Clock: ACPProloBd |3MCor

Vector 8800 Proto 22.20

Vector 8803 11 slot MB.,.. 29.95

ACP Extender w/Gonn 18.95

13SI0I MoiherBoard(WMC| 32.95 9510I MatherBoar(t(WMO.„29.B5 35101 MoihertEKpewftbM-3435 P'oc-Tecn Bare Boards' ,tiAu.'

WMCFiopoyPCB 34.95

Rowv KB

(8-SHUGART) ..3»«

S1001AY5-B9101 Sound B<1_34S& Apple Sound Bd, 24,95

COMPUTER SPECIALS

oisco'

lOHTS'

LIST SALE

Apple II Plus 6K 1150.

PET3O01-16N 995 '95.

Eiidy Sorcerer w/16K 1099

Cromemco Sys III 6990 6290

Hoii/on I W/32K CALL

Pascal Microengine 1995.1595.

IPSI 1620 DiabloRO 3296 2695

AnaoeiDPeOOO 995 875

Cenlrortrcs Micro S-l 595 525

Soroc 10 1 20 995 795

Teletype Model 43 1349 1150

H.PlOl Plotter 1085 899

HiPlOl Digiliier 795 735

InlBMube II 895 784,

Alan 800 999 825.

Alan 400 549. 449.

TI99/4 1150.1025.

Leedeii l2~Monilor 1S9. 149.

Centronics 737 995. 609.

TrenconiT-100 375. 349.

SartyorMontlor Sanyo 15' Monitor Sanyo 13" Monitor

SOCKET SPECIALS

14Pinw/w2L .,

S .35

20 Pin W/W-2L

. 75

1B Pin s/l

22 Pin s/t

. . 16 15

14 Pin s/t

100/12.00

16 Pin s/l

100/13.00

Call lor volume pnano.

ra us A

470:' W0''»4

INS B2S0

KEYBOARD ENCODERS

AY52376 AY5-3600 IID0165

74C922

13.75 13 75 9 95 9 95

',2b 16

• 41 a » iMCK aouiti BEKSin • single sioes

S'. tVfHIII REIIIFOIICEIIEIII RIHE

^77 01 Soli SecKwd IRS SO tt( bT7-n 10 Hole HM NS Pa* ttc

577-tG IG Hole tim) hlcroDMS

• ig TUCIU. MUlU SIDID. MlllE Kilin Vm

550-CI SCI SetlwM SA 450 MPI i7 55l)-10 IG tioii; Hard BASf WANGCO 650 16 15 HM Hard Mcro'

• g lOOStEmiFlEDDIIKEnES fOflOfi 01 Solt Single Densilv 3740 f oaoo 3? 1? Hard Srngie Dtns<ly Sfuq >080? 01 Soil DoutW Otnsitv i-iO 'naso-ni Soli Dojiiit Surt DouWe Density 1740

VOLUME DEALER PRICING AVAILABLE WE ALSO STOCK DYSAN-CALL

129.95

129» TERimS:

^ ^-.^ M/C, VISA

I29SS AMEX. CB. or COO COD reauires 250b deoosil Charge Oroers please include e»piralion date Foreign pay SI, J U.S. funds. Order by pnone. mail or i:7i MINIMUM $10.00 Please m

itelude magaiine issue and phone no " ' SHIPPING. U S A add S2 OO tor I11SI 2 lbs. For surface add 30e tor addi

ug ts 70C for addr

ui ts tKinal lbs. FOREIGN; Add 10% sNpping and handlino- COtTa S1.85 exira. Not reeponsibts for typos. Some ■temi subject lo prior sale, we reserve right lo limit quantities, some ilermsubted lopreciausmetal adder. Retail pricing may vary from Mail

S39.t5

S33K) 3353 44 K] 49 S9

RETAIL STORES OPEN MON-sAT P.O. Box 17329 Irvlne, Calif. 92713 for international orders

IISSIi;:\;°c.;^in'o''a:TS;,*«%?r'°= rir.-^""" Ofect order Lines: (714) 558-8813 1310 E. Edmger ,7,4,953-o6«^

ST0RE.3: Mjw.T„m»..Bo»..s,nJo-.CAS5,3..»o»IM.70,o (800) 854-8230 Or (800) 854-8241 SantaAna.CA92705 TWX:910-S95-1565

Circle 7 on Inquiry card.

BYTEIklaylVSl 493

SN74O0N

7400

5N74156N

79

5N7401N

SN74157N

69

SN7402N

?s

SN7472N

.29

SN74160N

89

SN7fl03N

25

SN7473N

.35

SN74161N

89

SN7404N

2S

SN7474N

.35

SN74162N

.89

SN7405N

29

SN7475N

.49

SN74163N

.89

SN7406N

,35

SN7476N

.35

SN7'1164N

.89

SN7407N

.35

5N 7479N

5.00

SN74165N

.89

SN7408N

.29

SN7480N

.50

5N74166N

1.25

SN7409N

.29

SN74B2N

.99

SN74167N

2.79

SN74iaN

.25

5N74B3N

.69

SN74170N

1.95

SN74UN

.29

SN7485N

.89

SN74172N

4.95

SN7412N

.35

SN74B6N

.35

SN74173N

1.39

SN7413N

.40

1.75

SN74174N

.99

5N7414N

.69

SN7490N

.49

SN74175N

.B9

SN74I6N

.29

SN7491N

.59

SN74 1 76N

.79

SN7417N

.29

SN7492N

.45

SN74177N

.79

SN7420N

.2S

SN7493N

M

SN74179N

1.49

SN7421N

.29

SN7494N

.69

SN741UN

.79

5N7422N

.45

SN749SN

.69

SN74U1N

2.2S

SF47423N

.29

SN7496N

.69

SN74182N

.79

SN742SN

.29

5N7497N

3.00

SN741B4N

2.49

5N74aGN

.29

SN74100N

1.49

SN741BSN

2.49

SN7427N

.2S

SN74107N

.35

SN74190N

1.25

&N742BN

.49

SN74109N

.39

5N74191N

1.25

5N7430N

.25

SN74116N

1.95

SN74192N

.89

5N7432N

.29

5N74121N

.39

SN74I93N

.89

5N7437N

.25

SN74122N

.55

SN74194N

.89

SN7438N

.40

SN74123N

.59

SN7419SN

.69

SN7439N

.25

SN74125N

.49

SN74196N

.89

SN7440N

.20

SN74I26N

.49

SN74197N

.89

SN7441N

.S9

SN74132N

.75

SN 74198 N

1.49

SN7443N

.59

SN74136N

.75

SN74199N

1.49

5N7443N

1.10

SN74141N

.99

SN74221N

1.25

SN7444N

1.10

SN74142N

SN7425IN

.99

SN7-J4SN

.B9

SN74143N

3^49

SN74276N

1.95

SN7446N

.79

SN74144N

3.49

SN74279N

.79

SN74145N

.79

SN74283 N

SN7448N

.79

SN74147N

1.95

SN74284N

3.95

SN74SON

.20

SN74148N

1.29

SN7428SN

3.95

SN7461N

.20

SN74U0N

1.25

SN7436SN

.69

SN74S3N

.20

SN74151N

.69

SN74366N

.69

SN7454N

SN74152N

.69

5N74S9A

.25

SN74153N

.79

SN7436BN

.69

5N7460N

.20

SN74154N

1.25

SN 74390 N

1.49

SN7470N

.29

SN74155N

.79

SN74393N

1.49

74LS00

.29

74LS

74LS192

1.15

74LS01

.29

74LS193

1.15

74LS02

.29

74LS92

.75

74LS194

1.15

74LS03

■29

74LS93

.75

74LS195

1.15

74LS04

.35

74LS95

.99

74LS197

1.19

74LS05

.35

74LS9G

1.15

74LS221

1.19

74LS06

.29

74LS107

.45

74LS240

1.95

74LS09

.35

74LS109

.45

74LS241

1.95

74LS10

.29

74 LSI 12

.45

74LS242

1.95

74 LSI 1

.75

74L5113

.49

74LS243

1.95

74LSI2

.35

74LS114

.49

74LS244

1.95

.59

74LS122

.89

74LS245

2.95

74L5W

.99

74LS123

1.25

74LS247

1.19

74L515

.35

74LS125

.89

74LS24B

1.19

74LS20

.29

74LS126

.55

74LS249

1.19

74LS21

.35

74LS132

.99

74LS251

1.49 .99

74LS22

.35

74LS133

.89

74LS253

74LS26

.35

74LS136

.49

74LS2S7

.89

74LS27

.35

74LS13a

.89

74LS258

.99

74US2fl

.35

74LS139

.89

74LS260

.69

74LS30

.29

74LS151

.89

74LS266

.69

74LS32

.35

74LS153

.89

74LS273

1.95

74LS33

.59

74LS154

1.75

74LS279

.75

74LS37

.45

74LS155

1.19

74LS283

1.09

74L538

.49

74LS156

1.19

74LS290

.99

74LS40

.35

74LS157

74LS293

.99

74LS42

.89

74LS158

!99

74L5298

1.2S

74LS47

.89

74LSie0

1.15

74LS352

1.29

74LS48

1.15

74LSt61

1.15

74LS353

1.2S

74LS49

1.15

74LS162

1.15

74LS365

.75

74L551

.29

74LS163

1.15

74LS$4

.29

74LS164

1.25

74LS367

!75

.29

74LSU5

1.25

74t_S368

.75

74L5168

1.19

74LS373

1.9S

74LS74

74LSlGg

1.19

74LSTC

!s9

74LS170

2.49

74LS375

^89

74LS76

.45

74LS173

1.39

74LS3e6

!69

.49

74 LSI 74

.99

74LS393

2.49

.89 1.2S

74LS175

.99

74LS399

2.49

74LSS6

74LS181

2.95

74L5670

2.49

iShfin

74LS190

1.25

eiL595

1.95

'm

74LS191

1.2S

81LS97

1.95

74S00

.50

74S

74 S 244

3 25

74502

74S351

74 SOS

'so

74S133

.55

74S253

1 45

55

74S134

.69

745U

■„

74 S135

1.19

74S?5R

f ■ ^

74 SOS

50

74S136

1.75

74S260

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74''09

SO

745138

1.35

74S280

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74S10

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745139

1.35

74t?fiH*

4

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74S11

50

74S140

1.15

74 515

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74S151

1.35

741171

74520

50

74S153

1.35

74 5 374

3 49

74S22

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74S157

1.35

74 5387*

595

74S30

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74S158

1.35

74 5471*

19!95

74S32

.55

74S174

1.59

745472

19.95

74S40

.55

745175

1.59

74S473*

19.95

74S51

.50

74S188

4.95

74S474*

21.95

74S64

.50

74S194

1.95

74S475'

21.95

74S65

.50

74S195

1.95

745570'

7,95

74S74

.79

745196

3.95

74S571*

7.95

74586

.79

74S240

2.95

74S572*

19.95

74S112

.79

74S241

Z9S

74SS73*

19.95

74SIU

.79

74S242

3.25

74S940

lis

74SI24

.79

74S243

3.2S

74S941

lis

* LIMITED AVAILABILITY ON THESE PROMS

CA3013H CA3I123H

2.U 3.25

CA-LINEAR

CA30B9N CA3096N

3.7S 3.98

CA3039H

1.35

CA3130H

1.39

CA3IWN

1.30

CA3081N

2X0

CA3140H

1.25

CA30S9N

3.25

CA3082N

2.00

CA3160H

1.25

CASOtON

3.25

CA30S3N

1.60

CA3401N

.59

CASOtOH

1.25

CA30B6N

.85

CA3600N

3.60

CD4000

.39

CD40B2

,39

CD4001

.39

CD-CMOS

CO4093

.99

CD4002

.39

C 04098

2.49

CD4006

1.19

CD450G

.75

CO4007

.25

C 04041

1.49

CD4S07

.99

CD4009

.49

CD4042

.99

CD450B

3,95

CD«I10

.49

CD4043

.89

CD4S1D

1.39

CD«U

.39

CD4044

.89

CD45U

1.29

CD«U

.25

CD4046

1.79

C 04514

195

CD«U3

.49

CD4047

2.50

C0451S

2.95

CD«U

1.39

004048

C04S16

1.49

CDVIS

1.19

CD4049

.49

CD45ie

1.79

CO«U

.59

CD4050

.69

CD4S19

.89

CD«17

1.19

CO4051

1.19

CD4S20

1.29

COMU

.99

CD4052

1.19

C04526

1.79

CCM019

.49

C 04053

1.19

CD4528

1.79

cuoa

1.19

C 04056

2.95

CD4529

1.95

CD4021

1.39

CD4059

9.95

C04543

2.79

CD4022

1.19

CD4060

1.49

CD4562

11.95

CD4023

.29

004066

.79

C04566

2.79

CD4024

.79

CO4068

.39

CD4583

2.49

CD402S

.23

CO4069

.45

CD4723

1.95

CD4026

2.95

CD4070

.55

CD4724

1.95

CD4027

.69

CD4071

.49

MC14409

14.95

COAOn

.89

CD4072

.49

MC144I0

14.95

CD4025

1.49

CD4073

.39

MC14411

14.95

CD4030

.49

CD4075

.39

MC14412

11.95

CDfl035 L CD4040

.99

CO4076

1.39

MC14419

4.95

1.49

CD407a C 04081

.55 .39

MC14433

13.95

LITRONIX DISPLAY SALE

DL-4SO0 DL-fl507 DL-4520A j OL-4120A

GIT OGFLECTOR AHRflYS FOR CLOCKS

<ULT|.OI0IT REFLECTOR ARRAVS

DISCRETE LEDS

XC556R

.200

red

5/tl

MV50 .085" red

6/Jl

XC556G

.200'

groen

4/$l

XC209R .125" rod

5/ii

XC556Y

.200'

yellow

fl/Sl

XC209G .125" green

4/Jl

XC55GC

.200'

clear

4/il

XC209Y .125" yellow

4/Sl

XC22R

.200'

5/$l

XCS26R .185" red

5/51

XC22G

.200

green

4/$l

XCSXQ .185" grean

4/$l

XC22Y

.200'

yellow

4/Sl

XCS26Y .185" yellow

4/$l

MVlOB

.170

red

4/Jl

XCS26C .185" Clear

4/$l

XCIUR .190" red 5/$l

xcillG .190" grean 4/Sl

xciUY :i90" yellow 4/ti

xcitic .190" clear 4/91

BL-2 . .$.39ea.or3/$1*00'

C.A.

Type MAN 1 MAN 2 MAN 3 MAN 52 MAN 54 MAN 71 MAN 72 MAN 74 MAN 82 MAN 84 MAN 3620 MAN 3630 MAN 3640 MAN 4610 MAN 6610 MAN 6630 MAN 6640 MAN 6650 MAN 6660 MAN 6710 MAN 6750 MAN 6780 DLO304 OLO307 □ LG500

Common Anode

Polarity C.A.—red 5x7 D.M.—red C.C.-red C. A.—green C.C.—green C.A.—red C.A.—red C.C.—red C.A.-^ellow C.C.—yellow C. A.—orange C.A.—orange ± 1 C.C.—orange C.A.—orange C.A.—orange—DO C.A.—orange ± 1 C.C.—orange—DO C.C.—orange ± 1 C.A.—orange C.A.—red—DO C.C.—red ± 1 C.C.-red CO.—orange C.A.—orange C.C.—green

DISPLAY LEDS

CC. — Common Cathode

Price 2.95

1.25 1.25

Type DLG507 DL704 DL707

□ L728 DL741 DL746

□ L747 DL^O OL0847 OLO8S0

□ USB FND358 FN0359 FNO503 FNDS07

5082-7751

5082-7760

5082-7300

5082-7302

5082-7304

4N28

LIT-1

MOC3010

Polarity C. A.—green CO.—red C.A.—red C.C.—red C.A.—red C.A.—red ± 1 C.A.—red C.C.-red C. A.—orange C.C.—orange C.C.-red C.C. * 1 C.C.

C.C. (FNDSOO) C.A. (FNO510)

Price

1.25 1.2S 1.25 1.49 1.25 1.49 1.49 1.49 1.49 1.40

C.A.,R.H.O.—red .430 C.C.R.H.D.—red .430 4x7 sgl. dig. RHD .600 4x7sgl.dig. LHD .600 Overnge. char. (+1) .600 Photo XslstorOpto-lsol. .gg Photo Xslslor Opto-lsol. .69 Optically Isol.TrlacOrlver 1.25

1.50 1.50 1.2S 1.75 22.00 22.00 19.95

SOCKETS

^ ^ . _ , . RECEPTACLES

Test MTDot Sockets n

ZERO INSERTION FORCE

Part No. Pin« Price

214-3339 14 pin 5.95 216-3340 16 pin 6.49 218-3341 18 pin 7.95 220-3342 20 pin

* Nickel Boron Plating *G.F. PSF Plastic Body

* For testing IC's Part No. Pins Price 222-3343 22 p)n 9.95 224-3344 » pin 9.75 228-3345 28 pin 11.95 240-3346 40 pin 12.95

LOW PROFILE (TIN) SOCKETS

SOLDERTAIL (GOLD) STANDARD

8 Pin SG 14 pin SG 16 pin SG 18 pin SG 24 pin SG 28 pin SG 36 pin SG 40 pin SG

* Nickel Boron Plating *0.F. PSF Plastic Body

* Wire Wrap Contacts

Part No. Pins I

214-3592 14 pin 9.75

216-3593 16 pin 9.95

218-3594 18 pin 10.95

220-3595 20 pin 11.95

Part No. Pins Price

222-3596 22 pin 12.95 224-3597 24 pin 12.75 228-3598 28 pin 13.95 240-3599 40 pin 15.95

SOLDERTAIL STANDARD (TIN)

1-24

25-49

50-100

14 pin

ST

.27

.25

.24

16 pin

ST

.30

.27

.25

18 pin

ST

.35

.32

.30

24 pin

ST

.49

.•15

.42

2fi pin

ST

.99

.90

.81

36 Pin

ST

1.39

1.26

1.15

•10 pin

ST

1.59

t.45

1.30

WIRE WRAP SOCKETS (GOLD) LEVEL #3

1-24

2S-49

50-100

.59

.54

.49

.69

.63

.58

.79

.73

.67

.85

.77

.70

.99

.90

.81

1.19

1.08

.99

1.49

1.35

1.23

1.39

1.26

1.14

1.61

1.53

i.:ia

1/4 WATT RESISTOR ASSORTMENTS -5%

10 Ohm

12 Ohm

IS Ohm

18 Ohm

22 Ohm

$1.95

ASST. 1

Bea.

27 Ohm

33 Ohm

39 Ohm

47 Ohm

S6 Ohm

50 pes.

68 Ohm

82 Ohm 100 Ohm

120 Ohm 150 Ohm

$1.95

ASST. 2

Sea.

180 Ohm 220 Ohm 270 Ohm

330 Ohm

390 Ohm

SO pes.

470 Ohm

560 Ohm 680 Ohm 820 Ohm

IK

$1.95

ASST. 3

Sea,

1.2K

1.5K

l.BK

2.2 K

2.7K

BOpcs.

3.3K

3.9 K

4.7K

6.6 K

6.8 K

$1.95

ASST. 4

Sea.

B.2K

lOK

12K

15K

18K

SOpcs.

22K

27 K

33K

39K

47K

$1.95

ASST. 5

Goa.

56K

6BK

82K

lOOK

120K

SOpCB.

15QK

ISOK

220K

270K

330K

$1.95

ASST. 6

5aa.

390K

470K

S60K

680K

820K

SOpcs.

IM

1.2M

1.SM

1.BM

2.2M

$1.95

ASST. 7

Sea.

2.7M

3.3M

3.9M

4.7M

5.6M

SOpcs.

ASST. 8R

Includes Resistor Assts. 1-7 (350 pes.) $10.95 ea.

S10.00 MIn. Order - U.S. Fundt Only Calif. RMdants Add 6K Sain Tax Postaga—Add6%plus$1 Insurance

Spec Sheets — ZSi

Sand 41rf Postaga for your

FREE 1981 JAMECO CATALOG

PHONE

ORDERS WELCOME (415) B92-8097

ameco

ELECTRONICS

MAIL ORDER ELECTRONICS - WORLDWIDE 13B5 SHOREWAY ROAD, BELMONT. CA 94002 PRICES SUBJECT TO CHANGE

Part No. Function

7045IPI CMOS Precision Timer

704SEV/Klt* stopwatch Chip, XTL 7106CPL 3Vi Digit A/D (LCD Drive) 71D6EV/Klt* IC, Circuit Board, Display 7107CPL 3W> Digit A/O (LED Drive] 7107EV/Klt* IC, Circuit Board, Dl^tay 7116CPL 3Vl Digit A/D LCD Dis. HLD. 7117CPL 3Vl Digit A/D LED Dis. HLD. 7201IDR Low Battery Volt Indicator 7205IPG CMOS LED Stopwatch/Timer 7205EV/Kit* Stopwatch Chip. XTL 7206CJPE Tone Generator 7206CEV/Kit* Tone Generator Chip. XTL 7207AIPD Oscillator Controller 7207AIZV/Klt« Freq. Counter Chip. XTL 720eiPI Seucn Decade Counter 7209IPA Clock Generator 7215IPG 4 Func. CMOS Stopwatch CKT 7215EV/Klt" A Func. Stopwatch Chip, XTL 7216AIJI 8-Diglt Univ, Counter C.A. 7216CiJI 8-Digit Freq. Counter C.A. 7216DIPI 8-Dlgit Freq. Counter C.C. 7217IJI 4-Dlglt LED Up/Down Counter 7218CIJI 8-DigIt Univ. LED Drive 7224iPL LCD iVt Digit Up Counter OR I 72a6AIJL 8-Digit Univ. Counter 7226AEV/Kit* 5 Function Counter Chip. XTL 7a40IJE CMOS Bin Prog. Timer/Counter 7242IJA CMOS DlvIde-by-2S6 RC Timer 72S0UE CMOS BCD Prog. Timer/Counter 7260IJE CMOS BCD Prog. Timer/Counter 75S5IPA CMOS 555 Timer (8 pin) 7566IPD CMOS SS6 Timer (14 pin) 7611BCPA CMOS Op Amp Comparator 7612BCPA CMOS Op Amp Ext. Cmvr. 762ieCPA CMOS Ouai Op Amp Comp. 7631CCPE CMOS Tri Op Amp Comp. 7641CCPD CMOS Quad Op Amp Comp. 7642CCPO CMOS Quad Op Amp Com 7660CPA Voltage Converter 8069CCQ SOppm Band-GAP Volt Ref. Diode 2.50 8211CPA volt Ref/lndlcator 2.50 8212CPA volt Ref/lndlcator 2.50 * INTERSIL'S EVALUATION KITS

Price

14.95 22.95 16.96 34.95 15.95 28.95 18.95 17.95 2.25 12.95 19.95 5.15 9.95 6.50 11.10 17,95 3.95 13.95 19.95 32.00 26.95 21.95 12.95 10.95 11.25 31.95 74.95 4.95 2.05 6.00

l.« 2.20 5MV 2.25 5MV 2.95 5MV 3.95 lOMV 5.35 lOMV 7.50 lOMV 7.50 2.95

74C

74C02

39

74 C 221

1 95

74C04

.39

74C240

2^25

74C08

.39

74 C106

.75

74C244

2.25

74C10

.39

74 C107

1.83

74C373

2.49

74C14

.75

74C151

2.95

74 C 374

2.59

74C154

3.95

74 CM

39

74C157

2.25

74C903

1 IS

74C42

L39

74 C160

1.69

74C911

10 95

74C48

1.95

74 C161

1.60

74C912

10.95

74C73

.79

74C162

1.49

74C915

1.69

.79

74C163

1.69

74C917

10.95

74C8S

1.95

74C164

1.59

74C922

5.49

74C86

.99

74C173

1.39

74C923

5.75

74C89

6.95

74C174

1.39

74C925

7.50

74C90

L29

74C175

L39

74C926

7.S0

74C93

1.29

74C192

1.69

S0C95

.79

74C9S

1.59

74C193

1.69

80C97

.79

LH0002CN LMIOCLH

6J5 4.50

LINEAR

NESJQN LM702H

4.96 .79

LMllCLH

4.75

LM703CN

.89

LH0070-OH

6.05

LMMOT-5

1.25

LM7Q9N

.49

TL071CP

.79

LM3UT-12

1.25

LM710N

.79

TL072CP

1.39

LM340T-15

1.25

LM7tlN

.79

TL074CN

2.49

LM341P-6

.75

LM723N

.69

LH00a2CD

35.80

LM341P-12

.76

LM733N

1.00

TL082CP

1.19

LM341P-15

.75

LM739N

1.19

TL0B4CN

2.19

LM342P-5

.69

LM741CN

.35

LH0094CD

36.80

LM342P-12

.69

MC1741SCG

3.00

LM300H

.99

LM142P-15

.69

LM747N

.79

LM301CN

.35

LM348N

1.25

LM74BN

.59

LM302H

1.95

LM350K

5.75

LM1014N

2.75

LM3WH

1.95

LF351N

.60

LM1310N

1.95

LM305H

.99

LF353N

1.00

LMI4S3CN

.59

LM307CN

.45

LF355N

1.10

LM1488N

1.25

LM30eCN

1.00

LF3S6N

1.10

LM14a9N

1.25

LIV1309H

1.95

LM358N

1.00

LMi496N

1.95

LM309K

1.25

LM359N

1.79

LM1556V

1.7S

LM310CN

1.75

LM370N

4.49

LMISOON

2.95

LM311H

.90

LM373N

3.25

LM1B77N-9

3.25

LM312H

2.49

LM377N

2.95

LM16B9N

3.20

LM317MP

I.IS

LM3e0N

1.25

LM1B96N

1.75

LM317T

1.75

LM381N

1.95

LM2002T

1.49

LM317K

3.95

LM382N

1.79

LM2877P

2.05

LM318CN

1.95

LM384N

1.95

LM2a7eP

2.25

LM319N

L95

LM366N-3

1.29

LM2896P-1

2.25

LM320K-5

1.35

LM3S7N

1.45

LM3189N

2.95

LM320K-12

1.35

LM389N

1.35

LM3gOON

.69

LM320K-15

1.35

LM392N

.69

UM3905CN

1.25

LM320T-5

1.25

LF398N

4.00

LIVI3909N

1.15

LM320T-12

1.25

LM399H

5.00

LM3914N

3.95

LM320T-15

1.25

TL494CN

4.49

LM3915N

3.95

LM323K-S

5.95

TL496CP

1.75

LM3916N

3.95

LM324N

.99

NE510A

6.00

RC4136N

1.25

LM329DZ

.65

NE529A

4.95

RC415INB

3.95

LM331N

3.95

NE53IH

3.95

BC4194TK

5.95

LM334Z

1.30

NE536H

6.00

RC4195TK

5.49

LM335Z

1.40

NE540H

6.00

K 84428

4.25

LM3362

1.75

NE544N

4.95

KB4429

5.95

LM337T

1.95

N E550A

1.30

LM4500A

3.25

LM337MP

1.15

NE555V

.39

1CL3D38B

4.95

LM338K

6.95

LM556N

.99

LM130BON

1.29

LM339N

.99

NE554N

3.95

LM13600N

1.49

LMMOK-S

1.35

LM565N

1.25

?51iSN

1.3b

LMboSCN

1.^5

LMJ40K-lb

1.25

75451 ON

CAPACITOR CORNER

Value 10 pf 22 pf 47 pf 100 pf 220 pf 470 pf

50 VOLT CERAMIC DISC CAPACITORS

14 10-99 100+

.08 .06 .05

.08 .06 .05

.08 .06 .OS

.OOlUF .08 .06 .05

.0047UF .08 .06 .05

.OImF .08 .06 .05

.022MF .09 .07 .06

.047|UF .09 .07 .06

.IMF .15 .12 .10 100 VOLT MYLAR FILM CAPACITORS

.OOlmf .12 .10 .07 I .022mf .13 .11 .08

.0022mf .12 .10 .07 .047mf .21 -17 .13

.0O47mf .12 .10 .07 .Imt .27 ,23 .17

.Olmf .12 .10 .07 I .22mf .33 .27 .22 +20% DIPPED TANTALUMS (Solid) CAPACITORS

.1/35V . 15/35V .22/35V .33/35V .47/36V .68/36V 1.0/35V

.39 .34 .39 ' .39

.29

1.5/35V 2.2/35V 3.3/25V 4.7/2SV 6.8/25V 16/2SV 22/5V

.41 .51

.S3 .56 .45 .79 .69 .55 1.39 1.25 .95

MINI. ALUMINUM ELECTROLYTIC CAPACITORS Axial 1-99 100-499 500-1- Radial 1-99 100-499 SO0+

.47/SOV LO^OV

3.3/50V

4,7/25V

10/25V

10/SOV

22/25V

22/SOV

47/25V

47/SOV

100/25V

100/50V

220/25V

220/50V

470/2SV

1000/16V

2200/16V

.49 .69 .79

.47/2SV .47/SOV 1.0/16V 1.0/25V 1.0/50V 4.7/16V 4.7/25V 4.7/50V 10/15V 10/25V 10/SOV 47/50V 100/16V 100/25V lOO^OV 220/16V 470/2SV

.15 .13 .12

494 BYTE May 1981

sSnductorClock Modules

12V DC AUTOMOTIVE/ INSTRUMENT CLOCK

APPLICATIONS:

• In-dash autoclocks

• After-market auto/ RV clocks

• Aircraft-marine elks,

• 12VDC Oper. Instru. ■ Portable/battery

powered instrumnts. Features; Bright 0.3" green display. Internal crystal timebase. ± 0.5 sec./day accur. Auto.display brightness control logic. Display color filterable to blue, blue-green, green & yellow. Complete-just add switches and lens.

IVIA1003 Module $16.95

MA1023 .7" Low Cost Digital LED Clock Module 8.95 MA1026 .7"Dig. LED Alarm Clock/Thermometer 1B.95 MA5036 ^" Low Cost Digital LEO Clock/Trmer 6.95 MA1002.5"LED Display Dig. Clock & Xformer 0.95

2 National Semiconductor

RAM SALE

MM52gON-4 (MK4116/UPD416}.. $3.95 each

16K DYNAMIC RAM (250NS)

{8 EACH $29.95) (100 EACH $350.00/lotl

MM5290J-2 (MK4116/UPD416). . $5.25 each

16K DVNAMIC RAM (150NS)

{8 EACH S39.95) (100 EACH $475.00/lot)

MIVI5298J-3A $3.25 each

8K DYNAMIC RAM (LOW HALF OF MM5290J) 200NS {8 EACH S23.95) (100 EACH S25a,00/lotl

IVIM2114-3 $5.95 each

4K STATIC RAM (300NS)

(8 EACH S43.951 (100 EACH S450.00/iot)

MM2114L-3 $6.25 each

4K STATIC RAM (LOW POWER 300NS) (8 EACH $44.95) (100 EACH S475.00/lot)

EPROM Erasing Lamp

• Erant 2708, 2716.1702A, 5203Q, &204Q, ate.

• Erases up to 4 chips within 20 minutes.

• Maintains constant exposure distance of one inch.

• Special conductive foam liner aliminatesstaticbuild-up.

• Built-in safety lock to prevent UV exposure.

• Compact - only 7-5/8" x 2-7/8" x 2"

• Complete v/ith holding tray for 4 chips.

UVS-11E. ■.■■■■■.■■■$

JOYSTICKS

JS-5K

JS-100K

JVC-40

SK Linear Taper Pots S5.25

100K Linear Taper Pots S4.95

40K (2) Video Controller in case . . . $5.95

6-Dlgit Clock Kit

■ Bright .300 ht. comm. cathode display "Uses MM5314 clock chip

• Switches for hours, minutes and hold modes

• Hrs. easily viewable to 20 ft.

• Simulated walnut case •115 VAC oporation

• 12 or 24 hr, operation *lncL bII components, case &

wall transformer •Size: 6K" X 3-1/8" x 1%"

JE701 $19.95

^^(i^ JE215 Adjustable ISpP'Dual Power Supply

General Description: The JE215 is a Dual Power Supply with independent adjustable positive and negative output voltages. A separate adjustment for each of the supplies providesthe user unlimited applications for IC current voltage requirements. The supply can also be used as a general all-purpose variable power supply.

FEATURES:

• Adjustable regulated power supplies, pos. and neg. 1.2VDC to 15VDC.

• Power Output (each supply); 5VDC @ SOOrnA, 10VDC@ 750mA. 12VOC@) 500mA. and

1 5VDC & 1 75mA.

• Two, 3-terminal adj. IC regulators with thermal overload proteclion.

• Heat sink regulator cooling

• LED ■■on" indicator

■ Printed Board Construction

• 120VAC input

• Size: 3-1/2"w x 5-l/16"L >

JE21S Adj. Dual Power Supply Kit (as shown).

2"H

. $24.95

(Picture not shown but similar in construction to above) JE200RBa. Power Supply Kit (5VDC, 1 ampi . . S14.95 JE205Adaptcrerd.(toJE200) -S.'g a ■12V. S12-95 JE210 Var. Pwr. Sply. Kit, 5-15VDC, lo 1.5arnp. SI 9.95

MICROPROCESSOR COMPONENTS

- 8080A/80SOA SUPPORT DEVICES

INSSOaOA

DPs:iz or>m*

OPSilG DPtS*

DP8!?6

DPB?3B I NSm^

DP3351 DPBS3

DP82b7 DPa2S9 DPMTS DPa379 OPS300

opam Dpsm

ops3oe

CPU

B-Btl Inout/Output Priority tntarrupt Control

k Generalor/Drlvar

1. Com

3 (U

Prog. Peripheral I/O (PPI) Prog. DMA Controt Prag. Interrupt Control Prog. CRT Controllar Prog. KayDoartf/Dltplay IriiarUce Octal Bui Rscalvar Syitem Timing Element 8-BU Bt-Dlractlonal RbcbIvbi 8-Bll 8<-Dlr«ct)onal Receiver a-Btt Bl-btrectlatfit Receiver

6800/6800 SUPPORT DEVICES

MC6B0D MPU

MC6BKCP MPU wltn ClOCti and RAM NdCSSlOAPI IZSxS Static RAM

PeriDheral Intor. AOaol {MC«20) MC6ii& Priority Iriterrupt Conlrollar

f^cesioLS iosa!<e-Bii rom (Mc«A3o-e)

MC6850 Aiynctironous Comm. AOaoler

MC6B52 Synchronous Serial Data AOapler

MC6B6a O^Dps Digital MODEM

MC6S62 2Waops Modulitoi

MCfiBSOA Quad 3-Stiite flus. Trans. (MCSTJS)

MICROPROCESSOR CHIPS

zeo (780C) CPU (MK3aa0N) (SMHl) ZBQA <7Sa-I} CPU (MK38SaN.4}(4MHl) CPU

MPU

IDM2901ADC CPU—

MCS65a2 INSS035N-« IN5B0nN.fi I NSB(H0N4 I NSaOTON INSSQ73N

■e (Cor

MMSIOH MM1402 MM5a)3

MM5016H 500/512-ail

MMSQMN Octal BO-eit

MM503SN Octal BD-BH (MD4A) 1(I».B1I Dynj

MPU w/Clocit (6bK Byl MPU—B-Bil (6MHz) CPU—Sgl.ChtpB-BllllZSby CPU (256 Bytas RAM) CPU—« Bytai RAM

CPU w/Basic

CPU

CPU-16-Blt MPU-JS-Bit

-SHIFT REGISTERS

Dual 25-Blt Oynimlc Dual 50-Bit Dynamic Dual IDO-BII Static Dual S4-Bit Accumulator 156-811 Dynamic

29.9S (9.95

Ic/Acc

351SN 2S22V

sii\/

ZS!SV

2528 V 2S29V

AF121-1CJ AFia-lCJ (.MMAH 1.M334Z

Hex K-eW Static Dual 132-Slt Static Sl^Blt Dynamic ]02i1-Blt Dynamic Dual ;5G-Blt Static Dual 250-Elt Sialic Dual WO-Eil Static

FKo (Dual 80)

-DATA ACQUISITION —

Touch Tone Low Pass Filler Touch Tona Low Pais Filler Supsr Gain Op Amp Constant Current Source Temperature Transducer JFET Input OO Amp

Sam

IDC08WLCN 8-Bil

DAC0SO6LCN 8-Blt O/A Convortar lO.TSli L

-DATA ACQUISITION (CONTINUED)

ADC0BO9CCN

AOCOBIXCN

DACUXMLCN

OAClCOtLCN

OACKBOLCN

DACt02ZLCN

DAClZaUCN

CD4aSlN

AV.S-10H

1101

IllB (UPD116)

B-BIt A/D converter (B-cn. Muitl.) i a-BIt A/D Converter (IG-Ch. Multl.) ]C lO-Bit D/AConv. Micro. Comp. (O.CSK), 1! 10-aitO/ACanv.Mlcra.Comp.tO.m) ( 10-Blt D/A Convertar (0.01% Lin.) I ID-BIID/A Converter (0.20% Un.) i 12-Bll D/A Convoriar [O.aW Lin.) J 8-Channst Mulllnlexer 1 »K BAUD UART E

RAM'S

I02inl Dynaniic

256x.; Sialic

1024x1 Static

1024x1 Static

256x4 Static

W6x4 Static MOS

1024x4 Static 4S0ni

1924x4 Static 45Cnt Low Power

1024x4 Slat i4 Slat

41W

MM2147J

51Q1

MK Dynj 4096x1 Pj'

: 300ni

c 250n5

,1 ?0:ii

256 x 4 Sialic 1024x1 Dynar 2Kk1 Dynamic 409SK] Dynamic

Dynamic 150ni m Dyn. JOOni (lower Vt of MMS2WJ) UPD414/MK4a27 4K Dynamic IB-pIn TMS4IM4^SNL 4K Static TMS4a(S 1024x4 Static

PROMS/EPROMS

1702A 2K UV ErasaOlB PROM

MM5261

MM5262

MME29O/2107

MMHMJ-2(4116)

MM52%J-3A

TMS2J16

ROM

8K EPROM (450nsl (Single * 2WS PROM

32x9 PROM (Onen Collector 40% Bipolar PROM

NMOS READ ONLY MEMORIES

MCME6T1DP 128x9x7 ASCII Sniltea w/Gieak

MCM66T40P 128x9x7 Math Symool & Pictures

MCM667S0P 128x9x7 Alpha. Control Char. Can.

MICROPROCESSOR MANUALS

M-ZSO Uier Manuel

M-cDPia» User Manual M-26S0 Uisr ivlanual

SPECIAL FUNCTION

Dual MOS Clock Driver (SMZ] Dual MOS Cloch Driver (5MZ| Floppy Dlic Conlrollor

D5002SCN DSOOjeCN INS17I1N-1 lNS2eslN MMM167IV MM58I74N CDP402N

COP402MN

Com

r Rfl^l

N 32-Se9.VAC Fluor. Driver (2Cl-oln r>W

-TELEPHONE/KEYBOARD CHIPS "

00 Puih Button Talephonc Dialer

AV-5-9500 CMOS Cloch Gflneiatoi

AV-5-2376 Keyboaro Encoder (BS Hevi)

HOOUS-S Kayooard Encoder (16 keyi)

74C92Z KeytioarO Encoder (16 heyi)

T4C923 Keyboard Encoder (20 keyi)

MM53I90N Pu»1 Button Pulsa Dialer

MM57499N 9e/144-Key ssrlal Keyboard Encoder

DESIGNERS'SERIES Blank Desk-Top Electronic Enclosures

• High s^ength spoxy molded end pieces in maclia brawn finish.

• Sliding rear/bottom panel for service and component accessibility.

• Tap/bottom panels.080 thk alum. Alodine type 1200 finish (gold tint color) for best paint adhesion after modification.

• Vented top and bottom panels for cooling efficiency.

• Rigid construction provides unlimited applications.

CONSTRUCTION:

The "DTE" Blank DeskTop Electronic Enclosures are designed to blend and complement today's modern computer equipment and can be u^d in both industrial and home. The end pieces are precision molded with an internal slot (all around) to accept both top and bottom panels. The panels are then fastened to thick tabs inside the end pieces to provide maximum rigidity to the enclosure. For ease of equipment servicing, the rear/ bottom panel slides back on slotted tracks virhile the rest of the enclosure remains intact. Different panel widths may be used while maintaining a common profile outline. The molded end pieces can also be painted to match any panel color scheme.

Enclosure

Panel

Model No,

Width

PRICE

DTE-8

8.00"

$29.95

DTE-11

10.65"

$32.95

DTE-14

14.00"

$34.95

$10.00 Min. Order - U.S. Funds Onlv Calif. Residents Add 6% Sales Tax Postage —Add 5% plus SI Insurance

Spec Sheets — 25^

Send 41i^ Postage for your

FREE 1981 JAMECO CATALOG

ameco

ELECTRONICS

PHONE ORDERS WELCOME (415) 592-8097

MAIL ORDER ELECTRONICS - WORLDWIDE 1355 SHOREWAY ROAD, BELMONT, CA 94002 PRICES SUBJECT TO CHANGE

Bourns Potentiometer^

3/4 Watt Single Turn

(TOP ADJUSTMENT!

Values: 500(2 IK 2.5K SK 10K 26K 50K 100K 250K 500K EMeg

INDIVIDUALPRICING: 1-49 50-99 100-999 IK-up

.19 .17 .15 .12 GB174 $1.95/lot

(25 pieces all 11 asst. values)

To order: Specify Bourns 3355 — (Value desired)

AC and DC Wall Transformers

Part No

AC 250 AC 600 AC100Q AC1700 DV 9200 DC 900

Input

117V/60HZ 117V/60H2 117V/60HZ 11 7V/60H2 117V/60HZ 120V/60HZ

Output

12 VAC 250nnA 12 VAC 500fnA 12 VAC 1 amp 9 VAC 1.7 amp g VDC 2Q0mA 9 VPC 500mA

Price

$3.95

$4.95

$5.95

$6.95

S3.2 5

$3.95

CONNECTORS

DB25P D-Subminiature Plug S2,95

DB25S D-Subminiature Socket $3.50

DB51226 Cover for DB25P/S S1.75

22/44SE P.C. Edge (22/44 Pin! $2.95

UG8B/U BNC Plug S1.79

UG89/U BNC Jack 13.79

UG175/U UHF Adapter S .49

S0239 UHF PamI Recp $1.29

PL258 UHF Adapter S1.60

PL259 UHF Plug $1.60

UG260/U BNC Plug $1.79

UG1094/U BNC Bulkhead Recp , $1,29

TRS-80 16K Conversion Kit

Expand your 4K TRS-80 System to 16K. Kit comes complete with: * 8 ea. M(VI5290 (UPD416/4116) 16K Dyn. Rams ClMS) Documentation for Conversion

TRS-16K2 -lEONS $39.95

TRS-16K4 •250NS $29.95

JE610 ASCII Encoded Keyboard Kit

The JE610 ASCII Keyboard Kit can be interfaced Into most any computer system. The kit comes complete with an indusTriai grade keyboard switch assembly (62-kevs), IC's, sockets, connector, electronic components and a double-sideO printed wiring board. The keyboard assembly requires +5V & 150mA end -12V ® 10 mA for operation. Features: 60 keys generate the 126 characters, upcer ano lower case ASCII set. Fully buttered. Two user-define keys provided for custom applications. Caps lock for upper-case-only alpha characters. Utilizes a 2376 (AO-pin) encoder read-only memory chip. Outputs directly compatible with TTL/DTL or MOS logic arrays. Easy interfacing with a 16-pin dip or

18- pin edge connector. Size: 3'A"H x 14y/'W x 8'/."D

JE610/DTE-AK tas pict ured above) . . . $124.95

iccin 62-Key Keyboard, PC Board, * -70 nc JCu lU Ixll Si Components (no case} ip /V.aO .

K62 62-Key Keyboard (Keyboard only)... $ 34.95

DTE-AK (case only-3H"HxU"Wi<«WDj$ 49.95

JE600 Hexadecimal Encoder Kit

& em

FULLS-BIT ^ft LATCHED OUTPUT

19- KEY KEYBOARO

1

The JE600 Encoder Keyboard Kit provides two separate hexadecimal digits produced from sequential key entries to allow direct programming for 8-bit microprocessor or 8-blt memory circuits. Three additional keys ere provided for user operations with one having a bistable output available. The outputs are latched and monitored With 9 LED readouts. Also includedisakay entry strobe. Features: Full B-bit latched output for microprocessor use. Three user-define keys with one being bistable operation. Debounce circuit provided for all 19 keys. 9 LED readouts to verify entries. Easy interfacing with standard 16-ptn IC connector. Only -i-SVDC required for operation. Size: 3»"H x 8Vi"W x aU"D

JE600/DTE-HK (as pictured above) . .. ■ $99.95

ll-r./^rt t^-i 19-Key Hexadec. Keyboard, Ai-n nc JE600 Kit PC BiaralCmonls. (no case). .$59.95

K 19 19-Key Keyboard (Keyboard only! .... $14.95

DTE-HK (use only -3l',"Hx8H"Wx8H-'0) $44.95^

Circle 208 on inquiry card.

BYTE May 1981 495

This is ABSOLUTELY the LOWEST PRICE EVER for a Hi Speed (300 NS) LO-LO Power 32K RAI\/I. 4K by 1 Chips are organized in Selectable Banks.

* Extended Address Lines A16 - A17 * Phantom Line * 9 Regulators

DEALS □ DEALS □ DEALS

SHOP HERE AND

(7

lO

(MINIMUM ORDER $10.00)

SCHOOLS

DIP SWITCHES

POS.

PRC.

4

.88

5

.92

6

.95

7

.99

8

1.05

9

1.15

10

1.19

PINS

PC

WW

8

.10

.26

14

.13

.29

16

.16

.32

18

.18

.34

20

.22

.38

24

.32

.48

28

.34

.50

40

.45

.61

AMP - Need we say more? There is a difference in soclcets! Tiiese aren't the iowest prices you can find. But, If you've been"burned" before by bad connections in your computer, a few pennies for the best Is worth iti

RESISTORS .02 ea!

(100 PACK) %W

1.0

75

2.7K

22 K

220 K

4.7

100

3.3K

24 K

330K

6.8

150

3.9K

27K

470K

10

220

4.7K

33 K

680K

15

330

6.8 K

39 K

IM

22

470

10K

47 K

1.5M

27

680

12K

68 K

2.2IVI

33

IK

15K

TOOK

4.7M

47

1.5K

18K

150K

10M

68

2.2K

20 K

WIRE

WRAP

WIRE

Packed in 500 Lot Bundles (Length includes 2" x 1" Strip) Color - R, Bu, G, Y, Bk, W

100 ft. $3.00 - 500 ft. $9.50

50 ft. $1.65

2.5-3.25 3.0-3.35 3.5-3.50

4.0-3.75 4.5-4.00 5.0-4.50

6.0-4.75 7.0-5.00 8.0-5.50 10.0-6.50

OK WIRE WRAP TOOL $5.95

ST21 ST22 ST23 ST24 ST25 ST26

6 Amps 125 VAC

7 Amps 30 VDC

$1.25 ea.

DPDT STANDARD TOGGLE

(ON-NONE-ON)

(ON-OFF-ON)

(MOM ON-OFF-MOM ON)

(ON-OFF-MOM ON)

(ON-NONE-MOM-ON)

(ON-ON-ON)

NOBBIEST

LMM3K 3A.

REGULATOR

$5.50

TAB MOUNT

7805 +5V 1A

7905 -5V 1A

7812 +12V 1A

7912 -12V 1A

HEAT SINKS 49$

$1.25

♦ GOLD ♦

S-100-CONNECTOR Tl or Better

'//////////

SOLDER TAIL

WIRE WRAP

$2.50 $3.25

DIP PLUGS

PART*

PINS

PRICE

08DP

8

.40

14DP

14

.55

16DP

16

.58

24DP

24

.95

40DP

40

1.50

Socket and Dip Plug priced based on gold not exceeding $700 per ounce.

CONNECTORS

DUAL ROW .100

CARD EDGE

PINS

PRICE

PINS

PRICE

20

2.35

20

3.35

26

3.00

26

3.80

34

3.85

34

4.65

40

4.50

40

5.50

50

5.50

50

5.90

RIBBON - 20 to 34 @) 1.00 ft.

40 & 50 (a 1,30 ft.

CRIMPING 2.00 / CONNECTOR

OEM'S

Z-80-A

$6.95

4MHZ Beastie with extra instructions!

Z-80 SUPPORT

CTC - $6.55 SIO - $25.50 PIO - $6.50 DMA - $18.75 All 4MHZ (who wants 2MHZ?)

74LSXX

74LS00

.33

74LS107

.59

74LS221

2.95

74LS01

.33

74LS109

.59

74LS240

2.95

74LS02

.33

74LS112

.59

74LS241

2.49

74LS03

.33

74LS113

.59

74LS242

1.95

74LS04

.59

74LS114

.49

74LS243

1.95

74LS05

.39

74LSI22

.59

74LS244

2.95

74LS06

.39

74LS123

1.19

74LS245

8.95

74LS07

.39

74LS124

1.49

74LS247

1.19

74LS08

.59

74LS125

.89

74LS248

1.19

74LS09

.39

74LS126

.89

74LS249

1.69

74LS10

.29

74LS132

.79

74LS251

1.79

74LS11

.39

74LS133

1.19

74LS253

.95

74LS12

.39

74LS136

.69

74LS257

1.95

74LS13

.69

74LS138

.99

74LS258

1.95

74LS14

1.25

74LS13g

.99

74LS25g

2.95

74LS15

.49

74LS145

1.25

74LS260

.75

74LS20

1.95

74LS148

1.49

74LS266

1.15

74LS21

3.7

74LS151

.79

74LS273

1.75

74LS22

.29

74LS154

2.49

74LS275

4.39

74LS26

.39

74LS155

1.49

74LS279

.79

74LS27

.49

74LS156

1.49

74LS283

1.49

74LS28

.39

74LS157

1.49

74LS289

5.75

74LS30

.49

74LS158

1.49

74LS290

1.29

74LS32

.95

74LS160

.75

74LS293

1.95

74LS33

1.95

74LS161

1.99

74LS295

1.95

74LS37

.75

74LS162

1.25

74LS298

1.29

74LS38

.39

74LS163

1.25

74LS324

1.75

74LS40

.25

74LS164

2.15

74LS352

1.65

74LS42

1.39

74LS165

1.49

74LS353

1.65

74LS47

.79

74LS166

2.49

74LS365

.95

74LS48

.79

74LS168

2.95

74LS366

.79

74LS35

.25

74LS169

1.95

74LS367

.99

74LS54

.25

74LS170

1.95

74LS368

.99

74LS55

.70

74LS173

1.25

74LS373

2.95

74LS73

.79

74LS174

1.49

74LS374

3.95

74LS74

.59

74LS175

1.49

74LS377

1.95

74LS75

.79

74LS181

2.15

74LS378

1.95

74LS76

.79

74LS189

6.95

74LS379

1.95

74LS78

.49

74LS190

.99

74LS386

.59

74LS83

.95

74LS191

1.95

74LS390

1.95

74LS85

1.49

74LS192

1.95

74LS393

1.95

74LS86

.95

74LS193

1.95

74LS395

1.95

74LS90

.75

74LS194

1.49

74LS490

4.95

74LS92

.75

74LS195

.95

74LS668

1.69

74LS93

.95

74LS196

.95

74LS669

1.89

74LS95

1.29

74LS197

1.95

74LS670

3.55

74LS96

1.29

496 BYTE May 1981

Circle 418 on inquiry card.

DEALS □ DEALS □ DEALS

OUR BUYERS ARE IN CONTACT WITH EVERY MAJOR SUPPLIER AND O.E.M. BUY HERE AT 1000 PIECE

QUANTITY PRICES

ALL MERCHANDISE 100% GUARANTEED! 15 DAY FULL CASH REFUND!

^ S @ MICRO IV I. ill. SALES

JUST HOT STUFF

POWER SUPPLIES

If you can beat these prices we will be truly amazed. OEM's at 500 lot pay more than this. Call or write for full spec, sheets.

DISK POWER SUPPLIES

PRIAM-SHUGART

CENTURY

MICROPOLIS

+5V(

-5V@i.8A

+24V (? 7A

US-384

89.00

SHUGART - SIEMANS - IVIPI 5'/i"

+5VC

S.5A

+12V@l.9A

US-340

33.50

+5VC

+12VS14A

US-323

56.25

SHUGART

SIEMANS

CDC 8"

+5V(9i 1A

-5V(9).5A

+24V@ 1.6A

US-205

52.50

+5VC

a2A

-5V(s>.5A

+24Vl5>3A

US-206

69.00

+5V C

-5V(3i.6A

+24V ls> 5A

US162

89.00

+5V C

a 1.7A

-5V (5) 1.5A

+24V 6) 2A

US-272

69.00

+5V C

s 2A

+ 12V @ .4A

-12V (5).4A

US-HTAA

37.50

TELEVIDEO 912C

SOROCIQ120-$675.00 Televideo912C- 665.00 Televideo 9206- 720.00 ADDSR-2S - 710.00

Also have920C, SOROC, HAZELTINE, etc. What we don't have Is room on this page. Call Toll Free 800 number for prices.

C-ITOH PRINTER $499.00

Look closely at the photo and see other adds in this rag at $995.00. Perfect units, warranteed. Onlyc 500 pes. Same story, manufacturerer had too many.

S-100 CARD EXTENDER $12.50

(Gold Contacts)

As long as there is a price war, we will fight your battle. Compare at your local Dept.

store and buy U$ MICRO.

MEMOREX - VERBATUM - WABASH BASF FLOPPIES

BOX OF 10 ONLY;

5'/." 5%"

sy."

8" 8" 8"

SOFT HARD 10 HARD 16 SOFT 1 D SOFT 2D SOFT 2DDS

$2.65 ea^ 2,65 ea. 2.65 ea. 3.25 ea. 3.85 ea. 5.00 ea.

664 N. MICHIGAN AVE. * SUITE WW * CHICAGO, ILLINOIS 60617 CALL TOLL FREE: 1-800-435-9357 * MONDAY thru SATURDAY (ILLINOIS RESIDENTS CALL: 815-485-4002) * 8:00 a.m. to 6:30p.m.

TERMS: Prepayment - C.O.D. up to $100.00 - M/C Visa $5.00 Processing and Handling added to each order PLUS Shipping Charges. Please allow personal check to clear before shipment.

SPECIAL OF THE QUARTER SPECIALS OF THE MONTH

SI-MOD (KIT) ,^^gtM»-,

$ 189 .OO^g^ ^112^1^

Complete S-100 12 Slot Computer. Ample system power with regulated power for drives.

Excellent for Subsystem or Hobby use. 4 hours to build. (6 conn, incl., less fans)

DUAL DRIVE SUBSYSTEM

$995.00

$195.00 w/no Drives

If this looks like a Lobo Drive System, don't be fooled. Just because it 2 SHUGART 801R looks like one, works like POWER SUPPLY one, smells like one, and tastes like one (7) doesn't mean it has to cost like one!

TWIN VERTICAL DRIVES 5" $550.00 - 8" $980.00

Attractive, convenient and compact Two Drive l^^ass Storage includes Power Supply, Drives, Cabinets and Cables. Double Sided, Double Track available tool

Z-80 CPU (KIT)

The " first time this world popular CPU offered in Kit. 2 serial, 3 parallel, CTC, EProm Z-80 at 4 mhz. Software buad rate, etc. (less Prom Si cable)

$212.00

EXPANDABLE RAM *SPEC!AL*SPECIAL*SPECIAL*

This is the best all around 64K board you can buy. If after you see it, you don't agree return for full refund. Bank Select by extended address lines or I.O. 40H.

fHIMII

UP' ™ ''TW JT,,,

★ $389.00 A&T*

U$ - D$K $255.00

Double Density 8" and 5" Disk Controller disigned for S-100 IEEE standards. Uses Western Digital 1795, 1691 2143 Chip Set.

FANS $14.95

These are brand new, in the box fans. Not noisey bearing pullouts. Never agajn at these low pricest

3-1/8" ?ri„

4-5/8"

4116s

Expansion 16K Dynamic RAIVIs for Apple, TRS-80 S-100 systems. T.I., IVIostek Intel, Call for manufacturer.

$2.95

200 NS

DIP-80 $399.00

Don't be mislead by this LOW price. This is a rugged 100% Duty Cycle 7 by 7 Dot Matrix Printer. Brand new, factory warr.

4

• RS-232 ADD $65.00 • TRACTOR FEED ADD $70.00

2114s

^ $3.45

One of the world's twoi most popular STATIC* RAIVIs. Factory prime tested units. Sold in lots of 8 only. FUJITSU, HITACHI, etc.

200 NS

TMS-4044 MM-5257 INTEL 2147

$4.25

250 NS

The other of the world's most popular STATIC RAMs. This one is 4K by 1 organization. Don't buy Gold, buy these, the pi^ice won't lasti

2716s 2708s

$9.50 (450 NS) $6.95 (450 NS)

Remember when 2716s were $50.00 and hard to get? These units are so beautiful If s hard to

part with them. But we will, for a small price. Guaranteed!

SHUGART DRIVE 8" 801R

$395.00

Manufacturer had

too many, buys at 8" 851 R $585.00 1000 piece rate,

sales dropped, so we got'em. Fantastic buy, get them while they lastI Full warranty.

SIEMANS DRIVE

8" 120-8

Very Special Price on these BRAND NEW current production units Add $10.00 for Extended 1 Year Warranteel

$375.00

circle 418 on Inquiry card.

BYTE May 1981 497

p

HMI

IDWEST

OMPUTER

MPNEMLS

INVENTORY CLEARANCE SALE PRICES SLASHED!!

COMPUTER SYSTEMS

ALTOS MODEL ACS-8000-2 64k. 2 drive, single user $3769

MODEL ACS-8000-5MU2 112I(, 2 drive, two user $5809

APF IMAGINATION MACHINE Complete System $1015

APPLE II plus 16k $1096

ATARI 400 $492

ATARI 800 $877

COMPUCOLOR 3 8k complete package $1478

RADIO SHACK MODEL III 16k $899

EXPANSION INTERFACE OK $274

MODEL II 64k w/one drive $3499 We carry tlie complete RADIO SHACK line at a discount

SO SALES SDS-100 '6299

SDS-200 '$6699

ZENITH Z-89 (48k) $2447

PRINTERS

ANACOM 150 150 cps, bi-directional, 9x9 matrix ANADEX DP-9500

CENTRONICS MODEL 779 TRACTOR PRINTER

737 "Letter Quality" w//cable We Carry the complete CENTRONICS linel DIABLO MODEL 630 RO w/Tractors EPSON MX-70

MX-80 Tractor feed, bi-directional, 80 cps INTEGRAL DATA IDS445Gw/2K Buffer & Graphics w/Cable

IDS-460 w/Cable MPI MT-88 TRACTOR PRINTER w/cable

MT-88G Graphics printer w/ cable OKIDATA 82 Bi-directional w/tractor cable $862 83 15" Carrage/Bi-directlonal $1099 NEC SPINWRITER 5510 RO Serial '$2579 5520 KSR Serial '$2879 5530 RO Parallel '$2579 OKIDATA MICROUNE80 PRINTER 80 cps, 9x7 matrix $554 w/Tractors and cable $679 TEXAS INSTRUMENTS 810 Basic •$1499 TRS-232 PRINTER INTERFACE $59 Allows you to use any serial printer with the TRS-80.

$1319 $1529 $999 $815

*$2579 $399 $550 $752 $1209 $659

WE NOW TAKE

AMERICAN EXPRESS

Card J

TERMINALS

HAZELTINE MODEL 1510

• $1099

1520

*$1360

PERKIN-ELMER BANTAM

*$799

SOROC IQ 120

•$759

IQ140

•$1199

TELEVIDEO 912C

•$799'

920C

•$859

ZENITH Z-19

•$899

CALIFORNIA COMPUTER SYSTEMS

MODEL 2016C 16k Static RAM board, A & T 2200 MAINFRAME A & T MOTHERBOARD 12 slots, A & T

APPLE PRODUCTS

Model 7440 PROGRAMMABLE TIMER BOARD A &T 7470 3V4 DIGIT BCD A to D Converter A&T 7490 GPIB (IEEE 488-1978) INTERFACE A &T 7710 ASYNCHRONOUS SERIAL INTERFACE A &T 7712SYNCHRONOUS SERIAL INTERFACE A&T 7720 PARALLEL INTERFACE A & T 7811 ARITHMETIC PROCESSOR A &T 711412k ROM/PROM Module A &T

$242 $352 $101

$102 $202 $132 $142

$99 $356

$69

We carry the complete line of CCS products

SD SALES S-100 BOARDS

Expandoram (NO RAM)

KIT

$192

VDP-8024

KIT

$302

VDB-8024

A & T

$402

VDB-8024

A&T

$402

Z-80 STARTER KIT

$302

Z-80 STARTER SYSTEM

A&T

$382

SBC-100

KIT

$252

SBC-100

A&T

$305

SBC-200

KIT

$274

Versafloppy

Kit

$223

Versafloppy

A&T

$295

Versafloppy II Double Density

KIT

$305

Versafloppy II Double Density

A&T

$376

n

idwest Llomputer peripherals

WE PAY UPS CHARGES ON MOST ORDERS IN THE CONTINENTAL U,S.

1467 S. Michigan Ave. Chicago, IL 60605

498 BYTE May 1981

FLOPPY DISK STORAGE

CORVUS 11T 10 MEGABYTE HARD DISK

Fully compatible with TRS-80, APPLE II. and S-100

'$4029

MPI MODEL B51 $321 TRS-80 plug-in compatible 5.25" single headed 40 tracic drive. Comes complete with case and power supply. 90 DAY WARRANTY.

BARE DRIVES

(No Case or Power Supply)

5" MODELS

40 tracks, 5 ms.

Double headed, 80 tracks

80 tracl(S

160 Tracks, Double headed

MPI MODEL 51 MPI MODEL 52 MPI MODEL 91 MPI MODEL92

$254 $299 $299

5.25" POWER SUPPLIES WITH CASE

STANDARD MINI DISK POWER SUPPLY WITH CASE $80 DELUXE MINI DISK POWER SUPPLY w/CASE ft extender card $131 DUAL MINI DISK POWER SUPPLY w/CASE $121

DISK DRIVE EXTENDER CABLE

$16

DRIVE CABLES

1 DRIVE TRS-80 CABLE

2 DRIVE TRS-80 CABLE

3 DRIVE TRS-80 CABLE

4 DRIVE TRS-80 CABLE

We'll make any cable! Call us with specs.

$24 $29 $35 $40

THE DOUBLER by PERCOM DATA $203 Double density controller for TRS-80 Model I. With data separator. (Use your PERCOM DISCOUNT coupon)

DATA SEPARATOR by Percom Data $29 Stops read errors on inner tracks.

SOFTWARE

$49

NEWDOS (40 Track) NEWDOS -I- (40 Track) NEWDOS BO MICROSOFT FORTRAN

ZSOSoftcard Super Utility Make 80

Electric Pencil (disk)

10% off all RADIO SHACK software We carry SBSQ, Microsoft, personal software, Apparatt and many other brands. All at a discount.

00181

$139 $85

$305 $49 $14

$130

DISKETTES

( Prices per box of 10)

VERBATIM

SYNCOM

MEMOREX

5 1/4" Single sided, single density

$31

$35

$28

Single sided, double density

$40

$39

$32

Double sided, single density

$48

N/A

N/A

Double sided, double density

$48

$52

$40

8" Single sided, single density

$41

$31

$33

Single sided, double density

$51

$40

$41

Double sided, single density

$61

$49

$55

Double sided, double density

$61

$49

$50

When ordering diskettes, please give us your make and model number of computer or disk drive, or give us the brand and part number of the diskettes you are currently using.

5 1/4" LIBRARY CASE holds 10 disks BINDER HOLDER holds 2 disks

8" LIBRARY CASE holds 10 disks BINDER HOLDER holds 2 disks

FLOPPY SAVER

$3.95 10 for $7.95 $4.95 10 for $19.95 5 1/4" $14.95 8" $16.95 Refills also availablel

16k MEMORY KITS 200 ns $39.00 NEC UPD416C-2 prime dynamic RAM. Compatible with TRS-80, APPLE, or any computer specifying 4116 dynamic RAM.

HOW TO ORDER:

PHONE ORDERS: HOURS 10AM ■ 5PM CST MON - FRI

BY CHECK: Call in your orderthen send us a cashiers check or money order. This way we can have your order waiting foryou when your check arrives. Personal.checks require 10

14 days to clear.

BY CREDIT CARD: Just have your MASTER CHARQE or VISA or AMERICAN EXPRESS

handy, we'll do the rest.

MAIL ORDERS: NEW ADDRESS 1467 South Michigan Ave., Chicago, IL 80605.

ALL MAIL ORDERS: Send your NAME and STREET ADDRESS (We ship UPS), CITY,

STATE, ZIP CODE AND TELEPHONE NUMBER along with your order.

BY CHECK: Include a cashiers check or money order with your order. Personal checks

require 10-14 days to clear. For your safety, mail your order via insured mail. BETTER

SAFE THAN SORRY.

BY CREDIT CARD: Neatly type or print your MASTER CHARGE or VISA account number along with the expiration date and 4 digit interbank number (MC only). IL RES. ADD e% SALES TAX

SHIPPING INFORMATION: We pay all UPS ground service charges (USA only, BLUE LABEL EXTRA) on all items except those denoted with an asterisk (*). (*) items must go airfreight or truck and can be sent freight collect. FOREIGN ORDERS WELCOME. CALL OR WRITE. ALL orders F.O.B. Chicago, II.

WARRANTY INFORMATION: All Equipment carries a 90 day parts and labor warranty, unless otherwise noted. Warranty repair or replacement will be provided at no charge, excluding shipping costs. 10 DAY MONEY BACK GUARANTEE: If within ten days you return merchandise in new and re-saleable condition we will refund your original purchase price. All refunds, exchanges or repairs include original cartons, packaging, and manuals and be In new and re-saleable condition and accompanied by your original Invoice. A 10% re-stockIng fee may be charged on returns at our discretion. Not responsible for typographical errors Prices subject to change without notice Dealer Inquiries welcome TRS-aO- TANDYCORP

SAVE TIME.. .ORDER BY PHONE TOLL FREE: 800-621-3229 IN ILLINOIS: 312-987-1024

IDWEST

Klniaus

1467 South Michigan Av. Chicago, IL. 60605

We pay UPS charges on most orders In continental U.S.

Circle 264 on Inquiry card.

BYTE May 1981 499

0

0^

^ \V ,^^8212 3^B

0^ XG/ \C>^^^8214 4.65

•^■^^^i" 0 8224 3.25

'^J .C5 8221-'! . 5. v.";

"V 822f) .i.H,'-,

\-0 822K 4.95

V 82:!K 4.95

«8(X) 8243 8.00

SUPPORT 8250 . .. 14.95

IP 4.95 8251 6.50

6H2HP 15.95 H25,'i . ,, , 17.95

(i84HP 15.75 8255 6.,50

8«S0I» 4.80 8257 . 19.95

6852P 5.95 8269 .... 17.95

e875P 5.95 8275 49.95

68488P 27.M 8279 .... 15.95

Disk Drives

0^,

0}

Z-80A

6502 B800 6802 6809

MICRO 8035 PROCESSORS 8080A 8085 8748

10.95 12.95 11.50 11.96 17.95 39.95 24.00 6.59 15.95 59.95

BAUD RATE GENERATORS

■MC14411 10.00

1.84,3 MHz, xtal 4.95

Z-80 SUPPORT

3881 I'lO 8.75

3881- 4 I'KUMHz . 12.95

3882 CTC 8.75

3882- 4 CTC-4MHZ 12.95

3883 DMA 29.50

,3883-4 DMA-4MHZ 36.95

,3884 .S70 35.95

:«84-4 SIO-1 MHz . 39.95

Special Purchase - Save $50.00 Novation Cat Modem

300 baud, answer and originate

(We have

only 700

twailible at this

special price) IOM-5200A List price $189.95....'. $139.95

D-CAT 300 baud, direct connect modem IOM-5201A Special sale price $189.00

AUTO-CAT Auto answer/origiate, direct connect IOM-5230A Special sale price $239.95

MICROMODEM - D.C. Hayes

Auto answer/dial modem card for Apple or S-100

IOM-2010A Apple modem $349.95

idM-llOOA S-100 modem $375.00

JADE's new dual rfi'.s^ sub-assemblies include: Handsome metal cabinet with proportionally balanced air flow system, assembled & tested dual drive power supply, quiet whisper type cooling fan, power-cable kit, lighted power switch, approved fuse assembly, line cord, Neuer-Mar rubber feet, and all necessary hardware to mount 2-8" disk drives - it's all American made, guaranteed for six months, and it's in stock!

Dual 8" Sub-A,ssembly Cabinol

END-000421 Cabinet kit $225.00

END-000420 Bare cabinet $59.95

Single sided, double density disk drive sub-system END-000423 Kit w/2 8" drives .... $975.00 END-000424 A & T w/2 8" drives $1195.00

Double sided, double density disk drive sub-system END-000426 kit w/2 8" drives .... $1495.00 END-000427 A & T If'2 ti" drives $1695.00

8" DISK DRIVES

Highly reliable double den.'iily floppy di.-ili drioes Shugart HOIR single sided, double density

MSF-10801R SA-HOIR $425.00

Special Sale Price 2 for $790.00

Shugart 851R double sided, double density

MSF-10851R SA-851R $595.00

Special Sale Price 2 for $1130.00

Siemens FDD100-8D2 single sided, double density

MSF-201120 6 mo warranty $38S.OO

Special sale price 2 for $750.00

Qume Datatrak 8 double sided, double (Icn.sity MSF-750080 SA-85IS compatible .. $599.95 Special sale price 2 for $1160.00

JADE DISK PACKAGE

Double den.-iity controller, two H" double den.-iity floppy disk driue.'i. CP' M2.2 {configured for eon Irollerl. hardware and software manuals, boot PROM, cabi net, power supply, fan, & cables

Special package price $1395.00

UARTS AY5-1013A .. 6.25 AY3-1014A . 8.25 TR1602B 5.25

™S6011 5.95

IM6402 9.(X1

PROMS

''2708 t.TlH-i . H.25 It) for m.9(> ca 2716 ;2..5e .... 9.96

2716 ,ie 9.95

in for $7.05 ea 25:12 .11 . 21-1.00 2732 r,e 25.00

2758 ne 9.95

RAMS

211.02 2MH! 1.25

21l.n2A / AWfe

21111. 1' \tlh . . -.UM

2114LA ■/ MH: 3.75

4116 3.50

4161 MKxl 39.95

52.57 2 AW.' . . 6.75

52.57A ;.v;//.- 7.25

MKIHH 17.95

Accessories-Apple/TRS-80

'0^

16K MEMORY UPGRADE

Add KiK of RAM to your TRS-^O. Apple, or Exidy in junl minutes. We've sold thousands of these 16K HAM upgrades which include the appropriate memory chips (as specified by the manufacturer), all necessary jumper blocks, fool-proof instructions, and our I year fiuamnfrr.

MEX-16100K TRS-80 kit $29.00

MEX-16101K Apple kit $29.00

MEX-16102K Exidy kit $29.00

16K RAM Card - Microsoft

(There is life after 48K) MEX-16300A A&T $174.95

Z-80* CARD for APPLE

Two computers in one, Z-Hfl & f>.i02. more than doubles the piHcer & potential of your Apple, includes Z-SD* CPU card. CP'M 2.2. & BASIC XO

CPX-30800A A&r $279.95

APPLE CLOCK - Cal Comp Sys

Real time clock w/battery back-up IOK-2030A A&T $109.95

DISK DRIVES for TRS-80

I' more sioragi'. S limes faster. 40 track ivilh frer patch.

power supply, and cable

120 da\' ivarrantv. includes MSM-12410C Save $125.00:

$299.95

8" DRIVES for APPLE

Controller. DOS. iivo 8" double densisty drives, cabinet.

power supply. & cables

Special package price $1475.00

APPLE STICK - Micromate

Joy stick with pots for Apple II SYA-1510A A&T $49.95

VISICALC - Personal Sftwr

The ultimate program for your Apple 11 SFA-24101005M Complete package $139.95

PRINTER INTERF-ACE - CCS.

Centronics type J/'O card w/ firmware

Ibl-2041A A&T $99.95

AIO, ASIO, APIO - S.S.M.

Parallel & serial interface for your Apple (see Byte pf^ 1V

IOI-2050K Par&Serkit $129.95

IOI-2050A Par & Ser A & T $159.95

IOI-2052K Serial kit $89.95

IOI-2052A Serial A&T $99.95

IOI-2054K Parallel kit $69.95

IOI-2Q54A Parallel A&T $89,95

A488 - S.S.M.

IEEE 488 controller, uses simple basic commands, includes firmware and cable, I year guarantee, (see April Bytepg 11)

IOX-7488A A&T $399.95

S-100 Memory

MEMORY BANK - Jade

Printers

SPINWRITER - NEC

S-100 CPU

2810 Z-80* CPU - Cal Comp Sys

2 4 MHsZ-HOA' CPU with HS-232C serial l/Opurt and onboard MOSS 2.2 monitor PJiOM. front panel compatible. CPU-30400A A&T $269.95

THE BIG Z* - Jade

2 or 4 MHz switchable Z-SO* CPU with serial I/O. accomodates 2708.2716. or 2732 EPROM, baud rates from

7,5 to 9600

CPU-30201K Kit $145.00

CPU-30201A A & r $199.00

CPU-30200B Bare board $35.00

CB-2 Z-80 CPU - S.S.M.

2 <ir I Mlh Z-HI) CPU hmird with pnivisiun for up In KKof ROM or -IK of RAM on hoard, extended addrestiinfi. IEEE S-100, front panel compatible.

CPU-30300K Kit $199.95

CPU-30300A A&T $239.95

SBC-200 - SD Systems

•( Mlh Z KO' CPU with serial & parallel 1/ Operls, up to 8K of on-hoard PROM, software programmable baud rate generator. IK of on-board RAM. Z-80 CTC.

CPC-30200K Kit $339.95

CPC-30200A Jade A&T $399.95

S-100 Disk ControUer

DOUBLE-D - Jade

t)ouble density controller with the inside track. on-board Z80A*. printer part. IEEE S-100, can function on an

interrupt drii'en buss

IOD-1200K Kit $299.95

IOD-1200A 8" A & T $389.95

IOD-1205A 5'//'A&T $389.95

IOD-1200B Bare board $66.00

DOUBLE DENSITY - Cal Comp Sys

■5'/;" and 8" disk controller, single or double density, with

nn-board hoot loader ROM. md free CP/M 2.2* and

numiKil si'l,

IOU-1300A A iS: T $369.95

VERSAFLOPPY II - SD Systems

AV(r iliiuhle density controller for both 8" & .5l'i"

IOD-1160K Kit $379.95

IOD-1160A Jade A&T $439.95

S-100 Video

VB-3 - S.S.M.

(^W rhuruclcrs x 24 lines expandable to 80 x 48 (or a full page of text, upper & lower case, 266 user defined symbols, 160 x 192 graphics matrix, memory mapped, has key board

input.

IOV-109.'5K 4 MHz kit $345.00

IOV-1095A 4 MHz A&T $395.95

IOV-1096K 80 X 48 upgrade $39.95

VDB-8024 - SD Systems

80 X 24 1 0 mapped video board with keyboard I/O, and

on board Z-80.A *

IOV-1020K Kit $399.95

IOV-1020A -Jade A & T $459.95

VIDEO BOARD - Jade

ti4 characters x 16 lines. 7x9 dot matrix, full upper/lower case ASCII character set. numbers, symbols, and greek tetters. luirniaUreiierse/blinking video. S-100.

IOV-1050K Kit $99.95

IOV-X050A A&T $125.00

IOV-1050B Bare board $19.95

MAINFRAME - Cal Comp Sys

12 slot S-IOO mainframe with 20 amp power supply E.\C-1121(11! A&T .$429.95

ASCII KEYBOARDS - Microswitch

■'}S key plus numeric pad and control keys KBA-99058 A&T $39.95

ilrcle 207 on Inquiry card.

4 MHz. IEEE S-WO. bank selectable, 8 or 16 bit.

expandable from 16K to 256K

MEM-99730B Bare board $55.00

MEM-99730K Kit, no RAM $219.95

MEM-16730K 16K tiit $249.95

MEM-32731K 32K Ijit $289.95

MEM-48732K 48K kit $324.95

MEM-64733K 64K kit $359.95

Assembled & tested add $50.00

64K RAM - Calif Computer Sys

4 MHz bank port / bank byte selectable, extended addressing, 16K bank selectable, PHANTOM line allows memory overlay, 8080 / Z-80 / front panel compatible, MEM-64565A A&T $575.00

EXPANDORAM II - S D Systems

4 MHz RAM hoard expandable from 16K to t>4K

MKM-16630K 16K kit $275.95

MEM-32631K 32K kit $295.95

MEM-48632K 48K kit $315.95

MEM-64633K 64K kit $335.95

Assembled & tested add $50.00

32K STATIC RAM - Jade

2 or 4 MHz expandable static RAM board uses 2114L's

MEM-16151K 16K4MHzkit $169.95

MEM-32151K 32K 4 MHz kit $299.95

Assembled & tested add $50.00

16K STATIC RAM - Cal Comp Sys

2 or 4 MHz 16K static RAM board IEEE S-100, bank selectable. Phantom capability, addressable in 4K blocks MEM-16160A 16K2 MHz A&T ,.. $286.95 MEM-16162A 16K 4 MHz A&T ... $289.95 AIEM-16160B Bare board $50.00

PB-1 - S.S.M.

2708. 2716 EPROM board with built-in programmer

MEM-99510K Kit $139.96

MEM-99510A A&T $199.95

PROM-100 - SD Systems

2708, 2716, 2732, 2758, & 2516 EPROM programmer

MEM-99S20K Kit $219.95

MEM-99520A Jade A&T $269.95

S-100 I/O

I/0-4 - S.S.M.

2 serial I/O ports plus 2 parallel I/O ports

lOI-lOlOK Kit $159.95

lOI-lOlOA A&T $219.95

lOT-lOlOB Bare board $35.00

65 cps, bi-directional, letter quality printer with deluxe tractor mechanism, both parallel and serial interfaces onboard. 16K buffer, ribbon, print thimble, graphics, microspace justification, data cable, and self test/diagnostic

ROM,

PRD-55511 without 16K buffer ... $2795.00 PRD-55512 with IGK buffer $2895.00

MX-SO - Epson

132 column. 9 x 9 dot matrix, multiple fonts PRM-27080 Save $100.00 Call

MX-70

PRM-27070 With Graftrax // Call

Interface for Apple $110.00

CENTRONICS 737-1

9 X N dot matrix, letter qiiaUty, proportional spacing

PRM-15737 Parallel $726.00

With interface for Apple $825.00

SiQgle Board Computers

z-80* STARTER KIT - SD Systems

Complete Z-80* computer with RAM, ROM, I/O. display, keyboard, manual, and bluge area,

CPS-30010K Kit $369.95

CPS-30010A Jade A&T $459.95

AIM-65 - Rockwell

6502 computer with alphanumeric display, printer, & keyboard, and complete instructional manuals

CPK-50165 IK AIM $449.95

CPK-50465 4KAIM $499.95

SFK-74600008E 8K BASIC ROM ... $99.95 SFK-64600004E 4K assembler ROM $84.95

P8X-030A Poiver supply $64.95

ENX-000002 Enclosure $54.95

4K AIM, 8K BASIC, power supply, & enclosure Special package price $675.00

DISKETTES - Jade

Bargain prices on maf^nificent magnetic media 5VV' single sided, single density, box of 10

MMD-5110103 Soft sector $27.95

MMD-5111003 10 sector $27.95

MMD-5111603 16 sector $27.95

5'^" double sided, double density, box of 10

MMD-6220103 Soft sector $39.95

8" single sided, single density, box of 10

MMD-8110103 Soft sector $33.95

8" single sided, double density, box of 10

MMD-8120103 Soft sector $39.95

8" double sided, double density, box of 10 MMD-8220103 Soft sector $49.95

S.P.I.C. - Jade

Our new I/O card with 2 SIO's, 4 CfC's, and 1 PIO IOI-1045K 2 CTC% 1 SIO. i PIO .. $199.00

IOI-1045A A&T $259.00

1OI-1046K 4 CTC's. 2 SIO's, I PIO ,$259.00

1OI-1046A A&T $319.00

1OI-1045B Bare board if/ manual . . . $59.95 1OI-1045D Manual only $20.00

Software

CP/M 2.2 - Digital Research

Latest & most powerful release of CP/M

SFC-52506000D Manual set $24.95

SFC-52506000M oW disk & manual $149.95 SFC-52506000F 8" disk & manual $149.95

SDOS - SD Systems

DOS, CBASlC-2. Z-80* assembler/editor linker

SFX-55001000D Manual set $24.95

SFX-55001002M 5W disks & man $199.95 SFX-55001006F 8" disk & manual $199.95

S-100 CARD CAGE - Vector

19" rack mountahle. adjustable, holds 21 cards

VCT-CCKIOO AnodizedAl $47.95

Metal cage with card guides & fan mounting ENX-106601 Six slot $29.95

S PLACE ORDERS TOLL FREE

H Continental U.S. Inside California I 800-421-5500 800-262-1710

■Ft>r Technical Inquirivs nr Cuxlonifr .St-rricr call 213-973-7707

■ Computer Products

S 4901 W. Rosecrans. Hawthorne, Ca 90250 H TKRMS OK SALK: Cash, chfcks. m-dit c-ards, or

Purchase Orders from quaiifii'd firms and institutions.

Minimum order $l">.(10. Ciilifiirnia residents add fi"!. tax.

Minimum shippiiifj and handling chnrjie -S-i.lH} Pricing l^iind availability subject to chanjje without notice.

CAliFoRNiA DiqiTAl

Post Office Box 3097 B • Torrance, California 90503

Privale labeU-cl for California Uigital by ihe mosl respected proihici-rs of magnelic media, Each diskette la certified double density at 40 tracks. To Insure extended media llCc each di9ketlo la fnanufactured viith u rt-inforced hub-hole. And of cQurac, a plastic Hbrarv cise is inclmlc-d 1 t-VL-rv hox a! dlskisllfs. MM1J-CU5(01)I iU)

KiGirr INCH

le/Hln((le d ^l<le/d<ublL- li Uide/32 aoolor 7-10-32

.■ Hide/double D. 743-0 SCU'l'CH brand head cieanlng kit. $24.93 MMA-CKl&KB) please spucLfy S 1/4 U" Prtoes av^aUe oQ request tor: ^afie. cartridges, diskpnoka, volumn diskcttn.

TRS-80 ® APPLE II

s

5

16k memory (8)4116's

l'';intor-v priniG. Unconditionally )_:iiarenLec-d for one lull year. Add $3.00 for TRS-80 jumpers and instructions.

■ilia- 200ns 3.25 4116 150ns 3.75 4164 34K 49. 50

3. 00 2. 7:i 2. 50 3.50 3.25 3.00 45.00

STATIC

211^02 450ns.

21L02 250ns

2n4L4 450ns

2114L3 300ns

4044-4 450ns

4044-2 250ns

5257-3 300ns

1. 19 1. 49

3. 95

4. 25

4. 95

5. 50 4. 47

1. 05 1. 45

EPROM

2708 450ns 2716 5V. 2716 tri-volt 2732 Intel 2532 TI 2764

4.95 7.95 9.95 19.00 21.50

4.50 6. 50 9.00 17.50 19.00

3.75 5.00 8.25 16.00

2. 50 2. 75 4.00 4. 35 3.75

3. 25 4.50 7.50

direct connect Y<>"r choice

MODEM $169

Dlruct uunnucl niudunm cUniliiate loss of inforniullun duk-tothu carbon eoniprussIon jsBuciaied with nuouatlc niadcina. ChoosL- uilher of ttieSL- two urcat units. fhi- lliiivt r^.d iJ.it.i Syatfiiis lOJLl' is switch si?luctablc b7twi-i.-ii nii.-iwi r .md orlq Iliroirllv

1 UU '■.

MiMj-ia

IMJS iO;iJ/I.P .AUTO ..ANSWI'.!

SWITCHES

CONNECTORS

tiuUlJ EDGE CCtfiNECTCWS

3G/72 IJijiilal (Jroup S/1' .i.Ua

36/72 DigUal Group W/W 6-60

43/86 Molorota 6800 SAT BM

43/BS Moio. BBOO W/W T.OO

6.15 6.15 6.85

II l>ln S.10 S.iil

14 pin .10 .01

16 pin .12 .tl

18 pin .15 .i:

Uii 2:^^ lVi!i.iltIJii lujo-l 2li' \.iJ iicnv malt 4.20 UC:i7S ruiiialc 6.00 IJC hood 2lP 2.25 1JU5UP male 5.50 UD50S female 0.40 UD.SO hood Z/P :!.60

1.30 1.20 2.00 2.U0 1.110

2.00 1.75

S,75 5.75

Hm»(JN CABLE CONNECTOKS 17/.M 5"iJl8l( 4.B5 4.15 3.!)5

■•n'M) nis-iio ri.r.:. s.os -1.70

i

NEW

from Shtxgart Technology

Megabyte Hard Disk Drive

Packaged in the same physical size as the industry standard 5 1/4" nunifloppy disk drive. The micro-Winchester stores thirty times as much data (6.38 megabytes unformatted), accesses data twice as fast (170 mlUirseconds) and transfers data twenty times faster (5.0 megabits per second. )

The ST506 is factory sealed to protect the media from environmental contaminates. Requires only DC voltage. Dual California Digital 5 1/4" enclosure, fe4 BAA ST506 drive and power supply. "X^UU

Shugart Associates SA400 removable media disk drive for above package, add: S-100 Apple controller scheduled For

spring release.

^300

^.Shugart Associates

801/ R Disk Drive 15 lbs.

ShiiiMi-i tii)l/u Willi cv ■•uii [iciwLT siipplv. muffin exhaust fan, """'a^ap pk'tL' in du:d oiiclomirL' with :<U ihe iit-cuasary h!inieBB(»|| CalllaS. ▼ f aS

DDruiin:iiUiiiiiii included. 3(! imunda. MSD-1801

Samu aa ,>hi)vu Um wiih two SliuH^rl UOlll illsk drlvoa. llUjS aOlJOlinda, M3I5-2U01 ''**9^ Disk drive uubli-. I> k-oi f.O conducior with edgc cnrd coltntietar at bolli enda. WCA-oriOS $25.00

Eicporl Disk rlrivL-s. 220V. 50Mllz add $50.00 per diak drive.

SURPLUS

DATA INPUT TERMINAL

ThU Keysiallon terminal wn» rccemly acquired froni the CMC dlviBlun of the Ponce Corporation. The unit vimb orlRlnilly deilftncd for InputlnK data directly onto rtijRiicllc li^ie.

I nf ^1 iiri'i:iiiiiii cMiK .iliiiiiiiiiii:': .liiiI tiiiirriTlaHl enclosure. Ml,-1-11'; J11, !, I'lii i-t i.i vi.i:.ii :i. 1 Mru' iiiapUy liimpi

.. :'!'..: .:r ..1|<<, i' i i:J r 1 r 1. 1. 11II'1 ' li'-.tlliT .1C knOwl C d ||

l.ir lerii^lrtid, wiili a Hiilc uii.iRm.iUun. cun be eHBlieered ■ for an S-100 compjier .uid video display: or *ilh allslit iho BookwcU AIM-6!> micro/computer.

r supply is available for ;in additional $30. Uce June Byte) condition. DriKlnj] acquisition iivi-r SIOO. 22 Ibi.

^9 Sankyo Magnetic Card Transport

I'liia Sankyo card iraii^puri ih c-iji i> uiid reirii'Miii.- otrtr 400 cb.ir;ii'i< i-s ;i atnulf 2x4" IIP alyle n awiulit; d Motorized niuchunism pulls tlieinaioiellc card across tin.-four i;l>,>iiii ht-ad in under two soconds. Idi?dl for ;inv i!:d.i iimfi-aaiiii; .ipplic.iiitii .11- i.unls of Inforniatlofi must be rjni!i'" Iv ! ri--vi .\. (.Viuin.J oosi i i>i.nin:fniatl«i and aantplo card inc-li^ ■ .. i SPC-SCU

$139.50

rrrrr ■

;ystem '

PORTABLE DATA ENTRY SYSTEM

These used data tiirmln.ds ii-t-n- uriuiiiully dL•si),^led for ri.'i.ill .-itun' onii i syaleniB. The cperaior entt-rs tlic inuuiiiory control niiiiilii:r. iii<;i-i,'h.Tiii!i..i hand and the unit price. After all periirient d.-ita has bvun enlertd. the ii.-nii >i ho<ise Is lelephtmed, the hundacl. ia placud in the acoustic cuuplur on uii Ihe ri corded inrorinatlon Is transmitted back the masler computer.

t^acli system Includes: Caaaelte drive imlt; Removable hex keyboard with LEU display; Five Gould"D"NiCads with eharger: Acoustical coupler and UB25 cable. Ml unlla removed from SLTvice in worklni; condition. Original coat over j;\,'i0O.

Regulated $1195 t_

Power Supply IIB SvoltSamp .^ddKLilKa

All merchiiiuiise sold by California digital is premium grade, Sliipping: First five pounds $2.00; each additional add .$.40 Koreign orders 10% shipping. I£xcess will be refunded. California residents add G% sales tax. CCD's discouraged. Open accounts extended to state supported educational instttus and companies with a "Strong lJun «t Bradslreet ■ehouse: l.^iSOS Inglewood Blvd, Visitors by appoi

TOLL FREE ORDER LINE

(800)421-5041

TECHNICAL & CALIFORNIA

CAliFoRNiA DiqiTAl

Post Offiri,e Box 3097 B • Torrance, California 90503

MEMOREX

8"DISKETTES

WITH

FREE

LIBRARY CASE

lu^U of clKhl inch lla Uicttnl WM< foi iftcred thU load of prii'n nedla.

rhoBC diHkollcB are "UNBHAMJIiU" but itre suaranteeil flrat qualltv \l<r:iior«s Brand. ti)30eo BinfUv dun.) Like all dlaktues sotd by CnlKamlii DiKllal, a library caae Is sui^llud free with the purchase of i-vcrv box.

UY

WorU'M Beat Selling Printer

EPSO MX80

Immediate Delivery

CERTRDniCS

730 $595 737 *750

==== = 3101

= == ==== Display

= ^^="= Terminal

IBM Direct Price *129i California DlgHml

ADDS Regent 25 numeric cluster ADDS Regent 30 25th Status line AIJUS Regent 40 Uniited graphics

AIJDS Reeent 60 Block mode Ampex Uiidoufiu 80 Lwo page,detatch Dij^ital KquipiKunt VT-lOO Digital Equipment VT-132 Direct VP-800A emulator Hazeltine 1410 HazeUine 1420 Hazeltine 1500 Hazeltine 1510 Hazeltine 1520 liev.lL-tl Packard 2(i21A Hewlett Packard 2521P IBM 3101-10 character mode green IBi\l 3101-20 block mode Lear Seigler 3A upper case only Lear Seigler ADM5 Lear Seigler ADM31 Lear Seigler ADM42 Soroc IQ 120 Soroc IQ 135 NEW Soroc IQ 140 detatchable keyboard Televideo 912C Televideo 920C

Televideo 950C dietatchable keybd. Zenith Z-19

:urporiiiiiKi. J hw Lii.Uoi.TJf UO (t-iitarua roLiiovabl D pages (four optl«iall iluai proBruni kcjfd. half Intcimlty protL-t aiae aaa status Une. Transmits data «lther block, line or character mode. xceUent value. VDT-OBO ah^^tnc 41 lbs.

VIDEO nRMINALS

VDTVDTVDTVDTVDTVDTVDTVDTVDTVDTVDTVDTVDTVIJTVUT

vurvij'r

VUTVIJTVUTVDTVDTVUTVDTVDTVDTVDTVUT

•L42 Cil20

T912 ■T9iO

7-ia

VIDEO MONITORS

I3i\ic ise;i:^c lUMii-,

J'~.il |;ril |)huti|jiiur Am.liik 12"100 I.-.-.-il. x 100 t;reiin

1.1/. d. v loo-ao Mils., hi .jolor 13"

;.t-.(J rrrll [lluisplior

I'iuiasuiiLc color 10" Sanyo 9" BW Sanyo 12" green phos

.S;iiivo 15" BW

TOLL FREE ORDER LINE

(800)421-5041

TECHNICAL & CALIFORNIA

j>naster^riarge|

Circle 57 on inquiry card.

All merchandise sold by California Digital is premium grade. Shipping: First five pounds $2.00; each additionid add $.40 I'oreign orders 10% shipping. Ii^xcess will be refunded. California residents add G% sales liix. COD's discouraged. Open accounts extended to slate supported educational institutions and companies witli a "Strong Dun Brnd.street. " Warehouse: 15608 Inglewood Blvd. Visitors by appointment.

STOP

GO BACK TO PAGE 80

SAVE UP TO 10%

on any prepaid U.S. Mail or retail store order

OVER $100.00

From our 60 Page Color DETACHABLE

SPRING 1981 ENGINEERING SELECTION GUIDE

Beginning on Page 80

JUST ATTACH THIS COUPON TO THE FACE OF YOUR ORDER FORM

PRIORITY

ELECTRONICS

9161 DEERING AVE. • CHATSWORTH, CA 91311

DISCOUNT

i^^TT-n^^-KT ENGINEERING COUPON SELECTION GUIDE

the appropriate box

□ $100 - $149.99 Deduct

□ $150-$199.99 Deduct

□ $200-$299.99 Deduct

□ $300 - $399.99 Deduct

□ $400 - $499.99 Deduct

□ $500 & UP Deduct

$10.00 $15.00 $20.00 $30.00 $40.00 $ 10%

VALID ON PREPAID U.S. MAE, ORDERS RECEIVED BEFORE JUNE 15,1981

OR PRESENT THIS COUPON

AT OUR RETAIL STORE BEFORE JUNE 15,1981

*Sorry Discount Coupon Not Valid on Shipping Charges, Phone or Foreign orders.

ANOTHER FAMOUS PRIORITY 1 ELECTRONICS TRUCK LOAD PURCHASE 10 MHZ 16K A&T STATIC S-100 RAM FROM

GBT-143A List $349.00

$199.00

The RAM 14 provides 16K X 8 of reliable, totally static RAM storage. Conforming fully to the IEEE 696/S-100 bus standard, RAM 14 not only provides 24 address lines for 16 megabyte extended addressing capability, but also includes a number of features you would only expect to find in memory boards costing considerably more. Here's a partial listing of what makes RAM 14 your best choice!

Operates up to 10 MHZ (70 ns RAM Chips) Assembled & Tested

Meets or exceeds all IEEE 696/S-100 specifications (including

timing).

Fully static design eliminates the timing problems associated with dynamic memories.

Switch selectable choice of 24 address lines conforming to the IEEE 696/S-100 extended addressing specifications, or 16 address lines as used in older S-100 systems.

CompuPro

Ideal for multi-user installations.

Board is addressable as one 16K x 8 block on any 4K boundary.

Switch selectable PHANTOM disable and write protect. + 5 Volt operation (requires no other supply voltages). Low power operation (900 mA typical, 1200 mA maximum). 1 year Factory Warranty.

Circle 332 on inquiry card.

PRIORITY ONE ELECTRONICS 9161-B DEERING AVE. • CHATSWORTH, CA 91311

Terms: U.S.; VISA, MC, BAC Check, Money Order, U.S. Funds Only. CA. residents add 6% Sales Tax. MINIMUM PREPAID ORDER $15.00. Include MINIMUM SHIPPING & HANDLING of $2.50 for the first 3 lbs., plus 25c for each additional pound. Orders over 50 lbs. sent freight collect. Just in case...please include your phone no. Prices subject to change without notice. We will do our best to maintain prices thru MAY, 1981. SOCKET and CONNECTOR prices based on GOLD, not exceeding $700 "

Sales Prices are tor prepaid orders only. Credit Card orders will be charged appropriate freight.

Best Prices aiid D^n^ery!

'^RAIfy by intertec

Self containea computer with duat disks and two RS232C ports. Complete with CP'W 2.2 and BASIC.

32K Double Density, List $2995

64K Double Density, List $3345 $2883

64K Upgraded to Quad Density w/Speclal MInlMlcroMart Warranty SPECIAL $3395

VIDEO TERWINALS

/V£l/VEMULATOR (Intertec), List $895$ 749 NEW INTERTUBE lllLlst $895 ONLY $ M9 SOROC 120, List $995 SPECIAL $ 729

1Q140, List $1495 SPECIAL $1149

PERKIN-ELMER 550, List $997 $ 799

with anti-glare screen, $1027 $ 829

HAZELTINE 1410, List $900 $ 749

1420 $ 849

1500, List $1225 $ 879

1510, List $1395 $1089

1520, List $1650 $1389

LEAR SIEGLER ADM3A, Assembled . . $ 849

TELEVIDEO 912C, List $950 $ 789

920C. List SI030 $ 849

9500, List $1195 NEW $1039

PRIMflRS

ANADEX DP-8000 $ 849

DP-9500, List $1650 $1399

DP-9501, List $1650 $1399

PAPER TIGER IDS-445, Ust $995 $ 695

w/graphics op., incl. buffer, $1195 .. $ 789

PAPER TIGER IDS-460, Ust 1149

PAPER TIGER IDS-460G Ust 1199

NEW IDS PAPERTIGER 460 . List 1295 SI 149 NEW IDS PAPERTIGER 460G List $1394 $1199

NEC Spinwriters Call for Price

TELETYPE 43 KSR $1087

CENTRONICS 730-1 parallel interface .. NEW LOW $ 649 737 parallel interface . SUPER VALUE $ 829 779 w/Tractor, Ust $1350 $1049

703 w/Traefor, VFU, Ust $2975 $1695

704 w/Traetor, VFU, Ust $2350 $1595

Tl 810 Basic, List $1895 $1695

810/serial ft Centronics-style parallel interface. List $1940 $1735

810 w/full ASCII (U/LC), Vertical Forms Control, Compressed Print .. $1895

Tl 820 KSR, List $2165 $1895

Tl 745 w/full ASCII, List $1695 $1399

COMPRINT 912 w/parallel interface . . $ 559

912 w/serial interface. List $699 $ 589

AXIOM IMP I $ 699

MICROTEK, List $750 $ 675

OKIDATA Microline 80, List $949 $ 599

Tractor Feed Option $109

RS232 Serial Interface $ 99

HORIZON 1 ASSEMBLED & TESTED

32K, Double Density, List $2695 .... $2279 32K, Quad Density, List $2995 $2539

HORIZON 2 ASSEMBLED & TESTED

32K, Double Density, List $3095 $2619

32K, Quad Density, List $3595 $3049

48K, Double Density, List $3590 $3039

48K, Quad Density, List $4090 $3469

64K, Double Density, List $3830 $3239

64K, Quad Density, List $4330 ... $3669

FLOPPY DISK SYSTEMS

NORTH STAR MDS-A Assembled, List $899 SPECIAL $ 719

MORROWTHINKERTOYS" Discus2D, List $1199 OUR PRICE $ 998*

Discus 2D, dual-drive. List $1994 $1694*

Discus 2 + 2, A&T, List $1549 $1319*

Dual Discus 2-1-2, A&T, List $2748 . , . $2335* *Now includes CP/M" 2.2

Prom Pri^amers

SSM FBI Kit List $125 $106

SSM PB1 A&T List $190 $161

SD Computer Prom 100 Kit $236 $201

SD Computer Prom 10OA&T List $311 .. $264

FLOPPY DISK COS^TROLLEB BOARDS

NORTH STAR, DD,

Assembled, List $499 $399

MORROW Disl< Jockey 1, A&T ($213) . $189

Disl< Jockey 2D, A&T, List $479 $429

SD Versafloppy 1, Kit, List $284 $239

Versafloppyll, DD Kit, List$413 $349

Versafloppy II, DD, A&T, List $507 .. . $429

DELTA double density A&T ($385) $345

CONDUCTOR, double density A&T ... $269 INTERSYSTEMS FDC-2, A&T, $495 . .. $439 MICROMATION Doublet, DD, A&T . . . $429 TARBELL Floppy Disk Interface Kit $199

double density, A&T, List $495 $444

ESCON CONVERSION

FOR IBM SELECTRIC

Complete w/microprocessor controller and power supply. Factory built. User installs solenoid assembly or it can be done at Escon factory at nominal cost. Parallel jlRS-BO, Sorcerer, etc.), $575 $514

RS232 Standard Serial, List $599 534

IEEt-488 (for PET), List $660 584

TRS-80 Cable 25

CALIFORNIA COMPUTER SYSTEMS

Zao CPU BOARDS List $299 $269

DISK CONTROLLER 2422 List $399 .... $359

16K Static, A&T, List $349.95 $259

32K STATIC List $710 $599

64K DYNAMIC BOARD List $699 $589

CPU BOARDS

(assembled unless noteai NORTH STAR Z80A IZPB-A/A), $299 $254 CROMEMCO 4 MHz (ZPU-W), List $395 $335

4 MHz (SCC-W), List $450 $382

INTERSYSTEMS (formerly Ithaca Audio) new Series II Z 80, 4 MHz, List $395 . $349

SSM CB1 8080 A&T List $252 $214

CB1A Kit, List $183 $156

CB2Z-80, A&T, List $344 $289

CB2Kit, List $60 $221

DELTAZ-80, with I/O $289

SDSBC-100, List 413 $349

SBC-100 Kit, List $341 $289

SBC-200, List $471 $399

SBC-200 Kit, List $373 $317

WESVIORY BOARDS 32K SD ExpandoRAM Kiti

! CALL r Uft t RICES \

NORTH STAR 16K Dynamic RAM Board,

A&T (RAM-16-A/A), List $499 $420

32K A&T (RAM-32/A), List $739 $620

CROMEMCO 16KZ-W, List $49[) $419

64KZ-W, List $1795 $1269

MEASUREMENT SYSTEMS & CONTROLS (Guaranteed performance, incl. labor/parts 1 yr) DM6400 64K Board w/all 64K, $795 ... $659

DM4800 with) 48K, List $695 $650

DM3200 witfi 32K, List $595 $509

DMB6400 64K Board w/all 64K $859

DMB4800 with 48K $789

MORROW SuperRAM - all static, all A&T

16K, 4 MHz or 2 MHz, List $349 $299

32K, 4 MHz, List $699 $629

16K Memory Master, List $399 $339

24K Memory Master, List $549 $465

INTERSYSTEMS (formerly Ithaca Audio)

8K Static 2 MHz, A&T, List $165 $149

8K Static 4 MHz, A&T, List $195 $176

16K Static 2 MHz, A&T, List $475 $427

16K Static 4 MHz, A&T, List $495 $445

64K Dynamic, List $995 $895

CALIFORNIA COMPUTER

16K Static, A&T, List $349.95

$259

I/O Mapped

SD COMPUTER VDB-8024, kit, List$437 .369

Assembled, List $556 $469

XITEX SCT-100K, Kit ONLY $169.95

SCT-100A Assembled $189.95

SSM VB2 I/O, Kit, List $199 .$169

Assembled & Tested. List $269 $229

Memory Mapped

SSM VB1C, 16x64, Kit, List $179 *152

Assembled & Tested, List $242 W6

SSM VB3, 80-Char.,4MHz,Kit,List$425. -$359

4 MHz, A&T, List$499 $424

INTERSYSTEMS, lbxb4, A&T, List $1bb $149 ^Subject to change.

HEW CROMEMCO 16FDC DOUBLE DENSITY

DISK CONTROLLER List $595 OUR PRICE S505

SHIPPING AND INSURANCE: Add ^2.50 for boards, S6 for Selecinc Convenei or Floppy Disk Drrves, $7.50 fof Floppy Disk Systems. $15 for Horizon. SHIPPED FREIGHT COLLECT: SuperBrain. Centronic and T.I. printers. Contact us for shipping information on other terminals and primers.

Above prices reflect a 2% cash discount (order prepaid prior tp shipment). Add 2% to prices for credit card orders, C.O.D.'s, etc. Prices are subject to change and offers subject to withdrawal without notice

MiniMicrolviart, Inc.

1618 James Street, Syracuse NY 13203 (315)422-4467 TWX 710-541-0431

If North Star or Cromemco offer it..

WE HAVE IT!!

Immediate Delivery at Discount Prices

NORTH STAR Horizon 2

32K Double Density

Assembled and Tested

«Y$2619

ASSEMBLED

HORIZON 1, DD $2279 32K, OD, List $2995 2539

HORIZON 2, 32K, DD $2619

32K, QD, List $3595 3049

48K, DD, List $3590 3039

48K, QD, List $4090 3469

64K, DD, List $3830 3239

64K, QD, List $4330 .:... 3669

NORTH STAR APPLICATIONS SOFTWARE

{Exclusive lor use with North Star Disk Systems — specify Double

or Quad Density)

NORTHWORD, List $399 $339

MAILMANAGER, List $299 249

INFOMANAGER, List $499 419

GENERALLEDGER, List $999 799

ACCOUNTSRECEIVABLE, List $599 499

ACCOUNTSPAYABLE, List $599 499

NORTH STAR HARD DISK HD-18

18 megabytes, plugs into parallel port of North Star Horizon. Utilizes tried-and-proven 14" Century Data Marksman. List $4999. pp,^,^ $4^99

NORTH STAR MDS-A - Double (or Quad) Density Disk System, Kit, List $799 . OUR PRICE $669 Assembled and Tested, List $899 SPECIAL $719

NORTH STAR MEMORY BOARDS

16K Dynamic RAM (RAM 16-A/A), Assembled, List $499 $420

32K (RAM 32/AI, Assembled, List $739 $620

INTRODUCTORY SPECIALS ON ...

PREMIUM QUALITY BASF DISKS CERTIFIED FOR QUAD SYSTEMS

5"." DOUBLE DENSITY DOUBLE SIDED l,si$57,50 8" DOUBLE DENSITY DOUBLE SIDED lisi$75.00 .

Shipping t2.50 - Frn Shipping In Mulllpli 01 Two Bn i

(Bex of ten)

.. $38.95 .. $47.49

yU£l/l^ System 3

by CROMEMCO

Now with Dual Double Sided Double Density over 2 megabytes of Storage) 64K of RAM List $7995

LIMITED TIME

$6395

CROMEMCO SYSTEM 2 — Now double Density with Double Sided Drives, Quad Capacity mini floppy disc drives. List $4695 Only $3899

CROMEMCO Z-2H

Z-2H

l^ompiiier^ilsrenL.'

Full 11-megabyte Hard Disk system. FastZ-80A 4 MHz processor, two floppy disk drives, 64K RAM memory, RS232 special interface, printer interface, and extensive software available. List $9995

OUR PRICE $8489

NEW DOUBLE DENSITY CONTROLLER BOARD

From Cromemco

With built-in diagnostics — 16 FDC Controller List $595 OUR PRICE $505

Z-Z COMPUTER SYSTEM List $995 $845

SINGLE CARD COMPUTER - SCC-W 4 MHz. List $450 $382

NEW COLOR GRAPHICS INTERFACE - SDI List $595 OUR PRICE $505

CROMEMCO HDD — 11/22-megabyte Hard Disk for use with existing systems. Df\/1 A controller. Transfer rate of 5-6 megabytes/second

HDO-II. List $6995 OUR PRICE ONLY $5939

HDD-22. List $11,995 $10,189

SHIPPING AND INSURANCE: Add $15 or Horizons, $2.50 for Boards and Software. Hard Disk Systems and Cromemco systems shipped freight collect. Advertised prices are for prepaid orders. Credit card and CO D. 2% fiigher. Deposit may be required on C.Q.D. All prices subject to change and offers subject to withdrawal without notice.

- WRITE FOR FREE CATALOG

MiniMicroMart, Inc.

1618 James Street, Syracuse, NY 13203 (315) 422-4467 TWX 710-541-0431

Circle 270 on Inquiry card.

Computers, Disk Systems

TfMiTM I data ^ I systems

Z89-FA

List $2895

OUR PRICE $2395

Z-89GA

List $2595 ....$2149

A-87 Two Drive

Minifloppy System List $1195 $989

Z-47DA $3695

8" Two Megabyte List $3695 $3059

INTERSYSTEMS

formerly ITHACA AUDIO

The new Series II CPU Board features a 4 MHz Z-80A CPU and a-full-feature front panel. 20slot actively terminated motherboard, with 25 amp power supply (50/60 Hz operation, incl. 68 cfm fan). pps.i, ugt $1795

$1495

COMPLETE SYSTEM with InterSystem 64K RAM, I/O Board w/priority interrupt and double density disk controller board. Full 1-year warranty. List $3595

$2995

NEW! CROMEMCO SYSTEM ZERO

List $995 OUR PRICE $849

NEWI CROMEMCO SYSTEM ZERO/0

A complete 64K Computer with Double Density Disk Controller List $2995

OUR PRICE$2545

Companion Disk drive for above —

Quad Density — Totdl of 780 Kilobytes of

storage on the two drives List $1295

OUR PRICE $1099

Only $3644 for a complete 64K Disk System

SUPERBRAIN

BvlNTERTEC

64K Double or Quad Density units available. Uses two Z-80 CPU's. Commercial-type terminal with 12" monitor. Dual double density minifloppies. Over 350 kilobytes of storage (twice that with quad density drives). Two serial RS232 ports. I/O ports standard. Expandable with optional S-100 S-100 interface. Comes with CP/(v1tm 2.2 operating system. IvliniMicrolvlart can supply a wide range of CP/M development and application software.

W/64K Double Density, List $3495 .. $2869 W/64K Quad Density. List $3995 $3395

HEWLETT PACKARD

HP-41CV

HP-41 System I-$399.

(The HP-41CV and HP82104A

Card Reader) List $495.

HP-41 System II-$ 679. (The HP-41CV and HP 82104A Card Reader, HP82143A Printer/Plotter) List $840.

HEWLETT-PACKARD

HP-85A ■ ^t "^""

Computer

List $3250

$2749

MORROW

THINKER TOYS® DISCUS IVI26^'^

26 megabytes of formatted storage List $4,995

$4,199

THINKER TOYS® DISK SYSTEMS

Now includes CP/f^/l* 2.2

Discus 2D, List $1199 $1019

Discus 2D, dual-drive, List $1994 $1694

Discus 2 -^ 2, Assem., List $1549 $1319

Dual Discus 2-f 2, Assem., $2748 $2335

Ml Morrow systems now include CP/M' 2 2

MORROW

Discus 2D's IN STOCK

NEW! CROMIX FROM CROMEMCO

A New UNIX Like Disk Operating System.

With true multi-user, multi-tasking capabilities List $295 OUR PRICE S249

NEW! DOUBLE DENSITY CONTROLLER BOARD

FROM CROMEMCO

With built-in diagnostics 16 FDC Controller, List $595 OUR PRICESS05

RADIO SHACK TRS-80™

10% OFFh

Terminals and Printers

Intertec

EMULATOR

Software compatible with a Soroc IQ-120, Hazeltine 1500, ADM-3A or DEC VT-52. Features block mode transmission and printer port; 12" anti-glare screen; 18-key numeric keypad; full cursor control. List $895

OUR PRICE $749

NEW INTERTUBE III

Li.lS995 ONLY $749

12" display, 24 x 80 format, 18-key numeric keypad, 128 upper/lower case ASCII characters. Reverse video, blinking, complete cursor addressing and control. Special user-defined control function keys, protected and unprotected fields. Line insert/delete and character insert/delete editing, eleven special line drawing symbols.

TELEVIDEO TVI-912C

Upper and lower case, 15 baud rates: 75 to 19,000 baud, dual intensity, 24 x 80 character display, 12 x 10 resolution. Numeric pad. Pro grammable reversfble video, auxiliary port, self-test mode, protect mode, block mode, tabbing, addressable cursor. Microprocessor controlled, programmable underline, line and character insert/delete. "C" version features typewriter-style keyboard. List $950

OUR PRICE $789

HAZELTINE

1500 ONLY

$879f

PAPER TIGER

1410 w'numeric keypad. List $900 $749

1420 w.'lower case and numeric pad 849

1510, List $1395 1089

1520, List $1650 1389

SOROC

IQ-120

List $995

SPECIAL

$729

Q-140 List $1495 SPECIAL $1149

CENTRONICS

PRINTERS

NEW 730, parallel, friction, tractor ,

$679

NEW 737 parallel, friction, tractor.... $849

779-2 w/tractor (same as TRS-80 Line

Printer I), List $1350 1049

702 120 ops, bi-direct., tractor, VFU .... 1995

703 185 ops, bi-direct., tractor, VFU .... 2395

704 RS232 serial version of 703, $2350 . . $1995

NEC SPINWRITER

TM

Terminal/Keyboard as well as RO Printer Only models available. CALL FOR PRICES!

IDS 455 Paper Tiger, List $995 . $895 w/graphics option, incl. buffer, $1194 .. $989 TRS-80 cable 45

NEW IDS 460 QUALITY PRINTING AT MATRIX SPEED-LOGIC SEEKING PROPORTIONAL SPACING

w/aulo text iustificatlon

NEW IDS PAPERTIGER 460List $1295 . $1099 NEW IDS PAPERTIGER 46DG List $1394 $1149

TI-810

TI-810 Basic Unit, $1895 . ONLY $1595 TI-810 w/full ASCII (Lowercase), vertical

forms control, and compressed print . $1795 TI-745 Complete printing terminal with acoustic coupler. List $1695 .... $1399

RNflDeX

DP9500/DP9501 PRINTCRS

DP-9500, List $1650 $1349

DP-9501, List $1650 $1349

ANADEX 80-Col. Dot Matrix $849

OKI DATA

Microline80 ONLY $599

Tractor Feed Option $109

Serial interface $ 99

AXIOM IMP I $699

COMPRINT 912 w/parallel interf. $559 912w/serial interface, List $699 $589

MICROTEK, List $750 $675

920C (with 11 function keys, 6 edit keys and Above prices reflect a 2% cash discount (order prepaid prior to shipment). Add 2% to prices for credit 2transmission mode keys. List $1030 card orders, C.O.D.'s, etc. Prices are f .o.b. shipping point. Prices are subject to change and offers

ONLY $849 subject to withdrawal without notice. WRITE FOR FREE CATALOG.

MiniMicroMart, Inc.

1618 James Street, Syracuse NY 13203 (315) 422-4467 TWX 710-541 0431

circle 271 on Inquiry card.

Unclassified Ads

UNCLASSIFIED P

equipment to buy, considered for publlcatic spaced on plain white address infor These noti

who are soliciting or giving advice, or who have send in a clearly typed notice to that effect. To be must be clearly noncommercial, typed double rds or less, and include complete name and

ted one time only on a space available ide computer users clubs only. We confirmation of placement Is ap

d to appear in the magazine.

FOR SALE: Texas Instruments TI-59 and PC-100 print cradie with all documentation and manuals. In mint condition; s 150 Of trade for HP-97. Also, HP-67/97 Stat Pac I, ME I, EE I. CEI, Surveying, Navigation, and Business Decisions Pac; all for S50. Charlie Truax, 2862 King Edward Dr. B C5orado Hills CA 95630, (9I6| 933-3478 evenings.

FOR SALE: Extra paper. 14- and B'/i -inch widths. S15 a box or trade for a TRS40 disk drive. Van. (616) 429-6788.

FOR SALE: Perkin-Elmer letter-quali^ printer. KSR. 110 to 300 bps, good condition, switch-selectable U/C or full ASCII, half or full duplex RS-232C. Bill Touchstone. |2I6) 333-3114 9:30 ANil to 5 PM weekdays.

FOR SALE: Pascal microenglne. Western Digital W090 (Includes factoiy power supply and cabinet). High-speed UCSD Pascal computer with 64 K memory, single- and dual-density 8-inch floppy software, and all documentation. S1200 plus shipping. Dave Werner. (212) 998-3929.

FOR SALE: GE Termlnet 300 ASCII terminal with digital cassene, adjustable traaors, 10-15-30 cps, paper out, etc. Letter-like quality, not dot-matrix. Also. t3E acoustic coupled modem [Bell 103), All m excellent condition. Execute commands from disk file with Command Processor software. Includes RTC, printer formatting, dynamic I/O reconfiguration, plus fifteen more commands for North Star Disk (Horizon). Please send SASE, Rich Adamson, 7310 Adams, Lincoln NE 68507.1402)464-0718.

FOR SALE: Hazeltine 1500 CRT; S 700. Hazeltine 1520 CRT; S1100, DEC LA-36; S1250. Omnitech acoustic coupler: S150, Novation CAT acoustic coupler; S150. Above items less than three years old and wori<ing. 200 new vacuum tubes: S300.55 new Calectro & Lafayette panel meters; S165, Buyer pays shipping, Charles B Wall,' Rte 3 Wingate, Clari<svllle TN 37040. (615) 552-2199.

FOR SALE: Twenty-four conductor [shielded coax) computer grade cable. !^-inch O/D vinyl clad bundle. Ideal for lownoise interfaces. Conduaors appear to be silver plated and dielectric is teflon. SASE brings conductor sample. S0.95/foot

plus postage and handling. Maximum of thirty foot lengths. Also, wanted: rack-mount multidrive 8-inch floppy-disk system, Jim Beistle. POB 501, Gilbert AR 72636, (501) 439-2305.

FOR SALE: SwTPC Model H/IP-68, All working with documentation, PIA. and 4 K programmable memory; S200, Two 4K programmable memory boards; S75 each. 8K programmable memory board with boundary switch: S150. Two MPS serial Interfaces: S35 each, MP-LA parallel Interface; S35. AC-30 dual cassette Interface; S75. $600 takes. It all. Heitiert Friedman, POB 153, Malveme NY 11565; (516) 481-2717.

FOR SALE: Digital Group TVC-F 5l2<haracter video programmable memory/I.I Kbaud audlcxassette board with all documentation. Assembled and in [seifect working order. Also, listings for Z80 operating system, and documentation and listing for EDFORM1 text editor. All for S95 including UPS shipping, or make offer, Martin Tobias. POB 3766. Nashua NH 03061. (603) 889-0901.

FOR SALE: ISO Ipm Centronics PI printer [same as Radio Shack Quick Print) with cable to a TRS-80. Excellent condltton. S265 (50% of list), D E Johnson. RD 2. Box 197. Coming NV

14830. (607) 524-6740.

FOR SALE: IBM Selectric remote I/O terminal, with ASCII conversion. RS-232. as sold by WortdwWe for $645. Fully checked out with manual. Best offer over $400. Steven Mather-Lees. 6 Holly Ln, Hudson NH 03051.

FOR SALE: Antique computer system. 1954 Royal McBee LGP-30, 800 lbs. desk size. 6,5- by 7-inch magnetic dnjm memory holds 4096 words, 32 bits per word. 113 electron tubes, 1450 diodes, and 34 plug-in cards. Two Friden Flexowriters, paper-tape punch, and plotter internal CRT for display in registers. Best offer over S5000. Richard Petras. (215) 356-6637.

FOR SALE: Kilobaud Microcomputing issue #6 (June 1977) through issue #18 (June 1978) In very good condition. Conv piete. some marks. Best offer. Daniel Q Dye Jr. 4861 Gray St Denver CO 80212.

"The ideal software source...

''V^ Gcxjidn't find it So we founded it'

We looked for a supplier with an ultra-wide selection of software for all leading micro-computer models...(How does 600 different programs strike you?)

... witli an equally broad assortment of lilgli-quaiity peripherals... (The latest and the best.)

... and with a no-holds-barred guarantee accompanying every purchase. (Like a full refund within 14 days if for any

reason dissatisfied.)

We looiced for It. And when we couldn't find It... we founded It.

says Richard Taylor, noted software author and President, Programs Unlimited

master charge

GALL TOLL-FREE (800) 645-6038 (except NY') COMPUTER TO COMPUTER: Call (516) 334-3134 WRITE: Dept. 581B, Box 265, Jericho, NY 11753

Ask for our

FREE Catalog.

he software source'

visit our new Retail Center at 20 Jericho Tpke.. Jericho. Long Island. NY. Call (516) 333-2266 lor hours & directions.

l>nOGRAMS UNUMITCD

510 May 1981 © BYTE Publications Inc

Circle 335 on Inquiry card.

FOR SALE: IBM 3767 communications terminal. Excellent condition, with fomis feeder and cables. Make offer, will sacrifice. Barney Lejeune. POB 3935, Lafeyette lA 70502.

FOR SALE: SID Systems VD&a)24 video tmatd; S27S. Selectric typewriter. Model 73, with Micromadon S-lOO Interface; S 500. Sanyo i 5-inch video monitor: S1 SO. Cromemco 8 K Bytesaver with 270B programmer for S-lOO; S75. Processor Technology 3P + S parallel/serial I/O board. S-IOO. S50. Keytronics keyboard with numeric keypad and enclosure; SI75, SwTPC KBD-5 keyboard with enclosure; S30. George East. 38 Edwin St, Randolph MA 02368, (617) 963-2265.

FOR SALE: Centronics 730 7 by 7 matrix printer, same as RS Line Printer II. Almost new. in perfect working condition, s 560. Also, adapter port when no El for S20. G Kish. 227 W iWeadow Rd, Rockaway NJ 07866, (201) 627-0052 evenings.

FOR SALE: Heathkit H-19, smart video terminal, assembled and tested; S700. Heathkit H-14, microprocessor-based pnntcr. assembled; S700. SD Systems Expandoram 48 K, assembled and tested; S300. Jade Doubie-D. doubie-densicy, 5-inch or 8-inch floppy-disk controller with cable for 8-inch drive, assembled; S350. Everything includes documentation, manuals, schematics, etc. James Geiber, 12850 Kern Rd, MIshawaka IN 46544. |2I9) 259-9929.

FOR SALE: One almost new CAT/Novatlon modem, works very well; S100. One almost new Apple II disk drive with POS 3.3 controller; S425 or best offer. Jon Taute, 2314 S 40th St, Omaha NE 68105, (402) 556-6695 evenings only.

FOR SALE: Z80 computer 4K programmable memoiy, monitor, keyboard, readout-cassette Interface. EPROM programmer with sixteen I/O ports S-100; S32S. State logic analyzer: 16-bii input. 5 MHz. 16 LED. 4 hexadecimal readout edge clocking, forward and backward stepping; S390. 6809 computer: monitor, Editor/Assembier. RS-232, sixteen I/O ports, timer, cassene Interface; 5400. Mitra Gopaul, 3 Weymouth Ave, Toronto Ontario. M4C 1R6 Canada. (416) 698-4405.

FOR SALE: Three Godbout memory boards with 8 K. Fully assembled and tested. All for S280 or S95 each. Tl SR-52 calculator with PC-lOO printer S260. SSM VBl video board. Fully assembled and tested. S100.1 pay shipping. Chuck Terra, 8415 Bind Run. Missouri Cny TX 77489. (713) 437-1242 after 4 PM,

FOR SALE: Execuporr 300 ponabie terminal. Hard copy, built-in acoustic coupler, carrying case. Can also be used as printer. S600 plus shipping. MA Graziano, (203) 563-5750 after 9 PM,

FOR SALE: Teletype Model ASR33 In mint condition. Used as a system console, upgraded to a CRT. Will sell for best offer. David Wong. 1916 Grand Cone, New York NY 10457, (212|

294-8087 evenings.

FOR SALE: North Star 48 K double-density, two serial ports, one parallel output and one parallel input pott two 5-Inch OD disks: S3100. Intertube II, reverse vkleo, dual Intensity, extra

RS-232 porr, absolute addressing, protected data mode, line drawing graphics. 25 by 80, keypad; $650. L A Ludden, 30 Slanchard Rd. Mariton NJ 08053.

FOR SALE: 64 K Digital Group (Bytemaster) complete system. With Oasis 5.4, in perfect condition. Only S2500. S E Rudlin, 4600 Grove Ave, Richmond VA 232.9, (804) 353-1000,

FOR SALE: S-IOO boards: Biotech CGS-B08 color graphics with 6847 and 4 MHz 8085 processor on board: S275, Bytesaver I; $75, Polly (VTI) video-diSplay board. 16 by 64 characters with graphics symbols; S60. Cromemco JS-I joysc/ck; S50, Edward March Jr, 2093 Fox Ln, Des Plaines IL 60018, (312) 635-7625 home. (312) 541-7300 worit.

FOR SALE: NCR Model 761 cassette deck (Phillipstype). Computer controllable play, record, fast forward, re versed, $250. E J Haas. 3448 S Marcella Ave. Stow OH 44224.

FOR SALE: 8800B IS-slot mainframe: S400. MITS 3203 dualdisk drive; S800. MITS I6MCS 16 K static-memoty card; S200.

MITS 32-5ector disk controiier; S600. Pertec FD-410 drives; S300. 88-2SIO serial interface card; S200. QUME SJJrint Micro 3 interface card; S200. 88-Prom 1702 prom programmer for 8800B: SI50. LA-36 DECwriier 11; $800. Gene Friesen. 6435 Colby, Lincoln NE 68505, (402) 467-1903.

FOR SALE: Netromcs ELF ii boards. Two 4 K programmable memories. Each S72, both Si35. Giant Mon and I/O board; S30. Full BASIC (EPROM) board; S120. All for S260. All boards are wired and tested. Robert Foltz. 1911 Mulford Ave. Bronx NY 10461, (212) 863-0964 after 6 PM ET.

FOR SALE: These items by Percom: Data Separator; SIS, Microdos (OS-80 version 1. 14): S15, Patchpak; $4.50. All complete with manuals. Add SI for shipping and handling. Albert Nijenhuis, 4310 Osage. Philadelphia PA 19104, (215) 222-1279,

FOR SALE: Altair 8800b computer with 32 K memory, one serial I/O poa, ACR cassette-interface board, 2 K PROM board. MBL and DBL bootstrap PROMs, 3202 dual 8-inch disk drive and controller, Lear-Slegler ADM3A videodisplay teiTninal, Altair (Microsoft) cassette 8 K BASIC, cassette Extended BASIC, Disk Extended BASIC, and Altair disk operating system. All in perfect condition. Original value over S7300- Asking S4380 or reasonable offer. B Verner. 11404 Woodland Dr. Lutherville MO 21093, (301) 828-8422 evenings.

FOR SALE: Houston Instrument 11- by 11-inch bitpad, James Klentz, RR *1, Wamego KS 66547, (913) 532-3722.

NX^ANTED: Tax-deductible donations are urgently needed. We are engaged in many building and maintenance projects and need CB radios, antennas, lighting apparatus, microscope attachments, and video equipment, Paul Oravis c/o Queen Anne School, 14111 Oak Grove Rd, Upper Mariboro MD 20870.

FOR SALE: Manuals, schematics, and spare boards for Sanders Associates Model 720 Data Display System, Jeff Weger, 614 Willowood Dr, Apt 209, Carol Stream IL 60187,

FOR SALE: IMSAl multiple I/O (MIO) board. Two parallel ports, one serial port one control port and a Tarbell tapecassette Interface plus two cables and documentation. Best offer. Eric Aronson, N64 W26611 HIilcrest Cir. Sussex Wl 53089. (414) 246-3518 evenings.

BYTE's Ongoing Monitor Box

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Article

The Epson MX-80 and MX-70 Printers Extended Color BASIC for the TRS-80 Color Computer

The Commodore VIC 20 Microcomputer: A Low-Cost, High-Performance Consumer Computer DC Motor Controls: Build a Motorized Platform BYTE's Arcade

Washington Tackles the Software

Problem

Legal Protection for Computer Hardware and Software Dancing Demon from Radio Shack Wire-Wrapping and Proto-System Techniques

Speeding Up TRS-80 Graphics

An Integer Math Package for the 8080

Super STEP Wordsmith

Using Interrupts on the Apple II System Digital Plotting with the Apple II Computer

Recursion and Side Effects in Pascal DEMONS: A Symbolic Debugging Monitor

Build a Super Simple Floppy-Disk Interface, Part 1

A File Catalog System for UCSD Pascal Numerical Methods in Data Analysis

Author(s)

Cohan

Miastkowski

Williams

Ciarcia Williams, Liddil, Moore, and Holt

Kern

Becker Kolya

Mangieri

Bobo and

Knoderer

Carbrey

Robbins

Dahmke

White

Hallgren

Morris

Halsema

Nicholson and Camp Heyman Nguyen

February BOMB Falls on Tank

Steve Ciarcia captured first place

in tine voting with "A ComputerControlled Tank" (page 44), a description of his effort at wireless remote control. He will receive the S 100 prize.

James C Anderson took second place with "An Extremely LowCost Computer Voice Response System" (page 36), the lead article in our issue theme of "The Computer and Voice Synthesis." He wins the S50 second-place prize.

Third place was shared by IViark Zimmermann, who wrote "A Beginner's Guide to Spectral Analysis, Part 1" (page 68), and Roger IVlikel, who contributed "A/D and D/A Conversion—An Inexpensive Approach" (page 312).

May 1981 © BYTE Publicaliom Inc 511

fnqulry No.

Page No.

AB COMPUTERS 473 ABM PRODUCTS 174 ABRAMS CREATIVE SERV 490 ACTION COMPUTER 76 ADAPTIVE DATA & ENERGY 151 ADV ACCESS GROUP 244 ADV COMP PROD 492, 493 ADV MICRO SYS 416 ADVENTURE INTLSeS ALL ELECTRONICS CORP 415 ALPHA BYTE STORAGE 59 ALPHA BYTE STORAGE 363 ALPHA OMEGA COMP SYS 455 ALPHACOM, INC 87 ALTOS COMP SYS 82. 83 AMER COMP & TELECOMM 293 AMER BUSINESS COMP 485 AMER CUSTOM ELECTR 482 AMER MICRO PROD INC 286 AMER SQUARE COMP 239 AMSI 486 ANADEX 191 ANCRONA 483 ANDERSON JACOBSON 385 ANDERSON PERIPHERALS 403 APPARAT INC 61 APPARAT INC 63' APPLE COMPUTER INC 13, 377 APPLIED ANALYTICS INC 296 ARISTO POLKS 452 ASAP COMP PROD INC 227 ASAP COMP PROD INC 356 ASHTON-TATE 273 ATARI, INC 177 ATARI PERSONAL COMP 339 ATLANTIS COMP SERV 304 ATV RESEARCH 486 AURORA DATA CORP 422 AUTOCONTROL INC 488 AUTOMATED EQPTMNT 20 AUTOMATED EQPTMNT 256 AVOCET 332 AXIOM CORP 109 AXLON INC 371 B & B ELECTRONICS 457 BASF SYSTEMS 281 BASIC BOOKS 278 BAY TECHNICAL ASSOC 126 BELL, JOHN ENGN 487 BETA COMP DEVICES 476 BILLINGS COMP CTR 206 BIT BUCKET, THE 373 BMC INTERNATIONAL 103 BOVklER-STEWART 418 BUDGET SOFTWARE 482 BUSS/CHARLES FLOTO 420 BYTE BOOKS 208 BYTE BOOKS 209 BYTE BOOKS 210 BYTE BOOKS 211 BYTE BACK ISSUES 405 BYTE SUB 468 CITOH ELECTR INC 113 CALIF DIGITAL 602, 503 CALIF COMP SYS 21 CAMBRIDGE DEVEL LABS 399 CAMBRIDGE UNIV PRESS 377 CAMEO DATA SYS INC 357 CAVRI SYSTEMS INC 407 CAWTHON SCIENTF GRP 490 CENTEC CORP 466 CENTRAL DATA CORP 301 CEXEC INC 411 CFR ASSOCIATES INC 391 CHRISLIN INDUSTRIES 279 CLEV CONS COMP & COMPNTS 253 CLINICAL ANALYSIS 68 CMC INTL 180 CMC INTL 382

COLONIAL DATA SERVICE 399 COLOR SOFTWARE 389 COMPU-U-CON 325 COMPILER SYS 347 COMPUMART 124, 125 COMPUTER AGE 383 COMPUTER CASE CO 375 COMPUTER CITY 453 COMPUTER CITY CANADA 255 COMPUTER CO OF AM 383 COMPUTER DISC OF AM 298 COMPUTER DYNAMICS 482 COMPUTER FACTORY 333 COMPUTER FURN & ACCSS 288 COMPUTER MAGIC 455 COMPUTER MAIL ORDER 391 COMPUTER PLUS 294 COMPUTER SHOPPER 415 COMPUTER SPCLTIES 132. 133 COMPUTER STOP, THE 469 COMPUTER TECHNOLOGY 292 COMPUTER WRHSE-HI 447 COMPUTER WRHSE 141 COMPUTERS ETC 144 COMPUTERS ETC. 400 COMPUTERS ETC 428

31 32 33 34

35 36

453 37 38 39 40 41 42 43 44

85 71 72 73 431 75 76 77 78 79 80 81 82

447 COMPUTERS PLUS INC 484

96 COMPUTERS WEST 397

97 COMPUTERS WHOLESALE 146

98 COMPUTEX CORP 163

74 COMPUVIEW PROD INC 67

99 CONCORD COMP PROD 480 232 CONDOR COMP CORP 226

102 CONSUMER COMP 100, 101

103 COHVUS SYS INC 169 238 CPA SOFTWARE 457

• CRM USERS GROUP 369

104 CPU SHOP, THE 471

105 CROMEMC0 1,2

106 CRYSTAL COMPUTER 187

108 CUSTOM PERIPHERALS 490

109 CYBER INNOVATIONS 482

110 CYBERNETICS INC 64

111 DATA DESIGN 395

■ DATA DISCOUNT CTR 302

112 DATA HARDWARE 463

Reader Service

'Correspond directly with company.

113 DATA SAFE PRODUCTS 430

114 DATALEX COMPANY, THE 419

115 DATAMAX34

116 DATASEARCH 378

117 DATASOUTH COMP CORP 127

118 DATASOUTH COMP CORP 272

119 DELTA PRODUCTS 131

120 DENVER SFTW 00, THE 120

121 DENVER SFTW CO., THE 121

122 DESIGNER SOFTWARE 111

123 DIGIAC CORP 337

124 DIGIBYTE SYS CORP 406

125 DIGITAL GRAPHIC SYS 71

126 DIGITAL MARKETING 6

127 DIGITAL MARKETING 263

128 DIGITAL PATHWAYS 303

129 DIGITAL RESEARCH 297

• DIGITAL RESEARCH COMP 477

130 DIP INC 277

131 DISC/3 MART INC 405

• DISK SUPPLY CO 312 454 DISKS ETC 383

132 DISCOUNT SFTW QRP, THE 202

133 DJ "Al" SYS LTD 327

134 DMA 224

135 DOW JONES 199

136 DUAL SYS CONTROL CORP 14

137 DWP 482

138 DYMARC INDUSTR INC 399

139 DYNABYTE BUSN COMPCIII

140 DYNACOMP2B9

141 E/Z ASSOC 490

142 ECHO DESIGN & DEVLPMT 70

143 ECOSOFT395

144 EDUCATIONAL CRSEWRE 455

• EFFICIENT MNGMNT SYS 81

• ELECTROVALUE IND 455, 490

145 ELECTRONIC CONTROL 197

146 ELECTRONIC DESIGN 403

148 ELECTRONIC EQUIPMENT 484

149 ELECTRONIC SPECIALISTS 401

150 ELECTRONIC SYSTEMS 491

151 ELECTRON ICS CENTER 478

152 EPSON AMERICA 345

• ESCON 397

451 ESP COMP RESOURCES 194

155 ESSEX PUBLISHING 388

166 EXATRONINC99

158 EXECUTIVE SYS INC 26

169 EYRING RESEARCH 143

• FECINC484

160 FAIRCOM 182

161 FARNSWOHTH COMP CTR 252

162 FEITH SOFTWARE 490

163 FORDHAM 474

164 FORETHOUGHT PRODUCTS 371

165 FREDERICKTOWNE COMP 488

• Q & G ACCOUNTING 376

166 QEICO INC 307

• GENERAL ELECTR 145

• GENERAL INSTRUMENT 147

167 GIMIX INC 142

168 GLOBAL PARAMETERS 403

333 GNT AUTOM 368

169 GODBOUT ELECTR 246, 247

170 GORDON, MARK COMPS 404

• GTE AUTOM ELECTR LAB 178

171 H S E OOMPUTRONICS 213

172 H & E OOMPUTRONICS 215

173 H & E OOMPUTRONICS 217

174 HANLEY ENGINEERING 475 176 HARRIS CORP 456

176 HAYDEN BOOKOO INC361

177 HAYES MIOROCOMP PROD 93

178 HAYES MICROCOMP PROD 387

179 HCW3 ENTERPRISES 488

180 HEATH COMPANY 91

181 HELU CORP 486

182 HEMENWAY ASSOCIATES 249 344 HEURISTICS 54

183 HEWLETT-PACKARD 57

184 HIGH TECHNOLOGY INC 115

185 HOBBYWORLD ELECTR 310 188 HOUSTON INSTRUMENTS 27

187 HOUSTON INSTRUMENTS 27

188 HUTCHINSON IND CORP 375

189 IJCAI-81 467

• ILLINOIS COMPUTER 482

190 IMAGE PROCESSING SYS 482

191 IMS INTERNATIONAL 162

192 INFO UNLTD SOFTWARE 176

193 INMAG371

194 INNOSYSINC98

195 INNOVATED SFTW APPL 282

196 INTEGRAL DATA SYS 89

197 INTEGRAND 379

198 INTLGNT CONTROL SYS 283

199 INTLGNT DEVICES MN 486

200 INTERACTIVE MICROWARE 386

201 INT'L MICRO SYS 343

202 INTERTEC DATA SYS 16

203 INTERTEC DATA SYS 97

204 INTROL CORP 484 206 IPEX INT'L 453

206 ITHACA INTERSYSTEMS 8, 9

207 JADE COMP PROD 500, 501

208 JAMECO ELECTR 494, 495

209 JDR MICRODEVICES 489

210 JR INVENTORY CO 478

211 K MEQA TECHNOLOGY 359

212 KERN PUBLISHING 196

213 KLO-FOX 486

214 KONANCORP73

215 LARKS ELECTR & DATA 488

- LEADING EDGE PROD 234, 235

446 LIFEBOAT ASSOCIATES 139

217 LIFELINES 123 '

219 LNW RESEARCH 351

334 LOGICAL DEVICES 488

220 LOGIC TECHNOLOGY SERV 400

222 LOMAS DATA PRODUCTS 399

223 LONDE, PARKER & MICHELS 377

224 LYBEN COMP SYS 463

225 MACROTRONICS 453

226 MAGNOLIA MICROSYS 490

227 MALIBU ELECTR CORP 85

68 MANN, CHARLES & ASSOC 389

228 MAROT SFTW SYS INC 233

229 MARYMAC INDUSTRIES 114

230 MAXELL DATA PRODUCTS 335 267 MCS 488

• MEAS SYS & CONTROLS 28. 29

233 META TECHNOLOGIES 268

234 META TECHNOLOGIES 373

235 META TECHNOLOGIES 393

236 META TECHNOLOGIES 462

237 MFJ ENTERPRISES INC 407

239 MICRO AGE COMP STORE 153

240 MICRO BUSINESS WORLD 232

241 MICRO COM 181 441 MICRO COM 367

■ MICRO COMP DISC CO 402

242 MICRO COMP STORE 92

243 MICRO D 12

244 MICRO DESIGN 455

245 MICRO HOUSE 380

246 MICRO HOUSE 381

247 MICRO MANAGEMENT SYS 291

• MICRO MINT 341, 365

249 MICRO PRO INT'L 167

250 MICRO SCI 119

251 MICRO WORKS. THE 376

252 MICROAGE 285

253 MICROBYTE243

254 MICROCOMP TECH INC 229

255 MICROCOMPEQUIP 476

256 MICRODASYS 161

267 MICROMAIL 164

268 MICROMATE ELECTR INC 406

259 MICROSETTE INC 76

260 MICROSOFT (CPDl 23

281 MICROTECH EXPORTS 387

262 MICROTEK INC 260. 261

263 MICROWARE 242

264 MIDWST COMP PERPH 498, 499

265 MIKOS472

266 MILLER MICROCOMP SERV 300

268 MINI COMP SUPPLIERS 401

269 MINI MICRO MART 86

270 MINI MICRO MART 506, 507

271 MINI MICRO MART 508, 509

272 MONROE SYS FOR BUSN 241

273 MORROW DESIGNS 193

274 MOUNTAIN COMPUTER 19

275 MOUNTAIN VIEW PRESS 401

248 MPI 237

■ MT MICROSYSTEMS 117

276 MTIINC314

231 MULTI BUSN COMP INC 362

277 MUSYS 190

278 NAT'L MULTIPLEX CORP 395

279 NCE SUPPLY CORP 397

280 NEBS 306

281 NEC AMERICA 94, 96

282 NEEOO 353

283 NEEOO 269

284 NESTAR SYSTEMS INC 183

■ NETRONICS 78, 154, 160

285 NORTHWEST COMPUTER 118

286 NOVATION 460

287 NOVATION 451

288 NOW MARKETING 184

289 OFFCL SFTW BUYERS GDE 467

290 OHIO DATA PROD CORP 393

291 OHIO SCIENTIFIC INSTR C IV i:92 OKIDATA CORP49

293 OLIVER ADVANCED ENGIN 294

294 OLYMPIC SALES 401

295 OMEGA MICRO COMPUTER 404

297 OMEGA RESEARCH 369

• OMEGA SALES CO 218. 219

298 OMIKRON 366

299 OMNIBYTE284

300 OMNITEC DATA 392

■ ONCOMPUTING 305

301 OPTIMAL TECHNOLOGY 384

302 ORANGE MICRO 155

303 OREGON SOFTWARE 107

304 OSBORNE COMPUTERS 53

305 OSBORNE/MCQRAW-HILL 398 30 OSM COMPUTER 315

306 OSM COMPUTER 486

• OWENS ASSOC 88. 448. 449

307 P & S ELECTRONICS 488

308 PK SYSTEMS 256

309 PACE INC 403

310 PACIFIC EXCHANGES 223

311 PACIFIC EXCHANGES 415

312 PACIFIC EXCHANGES 463

313 PACIFIC EXCHANGES 482

314 PAGE DIGITAL 481

315 PALOMAR COMP EQUIP 317

316 PAN AMERICAN ELEC INC 472

317 PASSPORT DESIGNS 414

318 PASSPORT DESIGNS 421

319 PCD SYSTEMS INC 72

320 PEACHTREE SOFTWARE 330 446 PELICAN PROGRAMS 455

321 PER COM DATA 7

322 PER COM DATA 35

323 PERSONAL COMPUTERS 156

324 PERSONAL MICROCOMPS 349

325 PERSONAL SOFTWARE 31

326 PHASE ONE SYS INC 313

327 PICKLES & TROUT 391

328 PIICEON 203

329 POLY PAKS 457

330 POTOMAC MICRO-MAGIC 136

331 POWER ONE INC 150 218 PRENTICE CORP 280

■ PRIORITY ONE 250

332 PRIORITY ONE 504, 505 101 PROF COMP STORE 320 336 PROGRAMS UNLTD 510

336 PROMETHEUS PRODUCTS 388

337 PURCHASING AGENT. THE 290

• QANTEXDIV329

338 QUALITY COMP PARTS 482

339 QUALITY SOFTWARE 246

341 QUASAR DATA PROD INC 311

342 QUEST ELECTR 479

343 QUIET DESIGNS INC 195

345 R K S ENTERPRISES INC 276

346 RC ELECTRONICS 490

347 RACET COMPUTES 379

348 RADIO SHACK 136

• RAINBOW COMPUTING INC 149

349 RANK ELECTRO-MEDIA 192

350 RCA SOLID STATE 18

351 RCA SOLID STATE 266

352 REDDOX CORP 201

442 ROBOTICS AGE 369

443 ROBOTICS AGE 385 452 ROCHESTER DATA 422

353 ROCKWELL INT'L 429

• ROCKWELL INT'L 105

354 S & M SYSTEMS 387 356 SC DIGITAL397

• S-100INC405

366 SAMS. HOWARD W 185

367 SCIENTIFIC ENGRG LABS 379

368 SCION CORP 5

369 SCITRONICS 62

360 SCITRONICS 238

• SCOTTSDALE SYSTEMS 32

361 SD SYSTEMS 68

362 SEABIRD PRESS. THE 457

363 SEATTLE COMP PRODS 267

364 SECURED COMP SYS 457

365 SELECT INFO SYS 321

366 SIERRA DATA SCIENCES 96

367 SIERRA NATIONAL 221

• SINCLAIR RESEARCH 137

368 SKYLES ELECTRIC WORKS 463

369 SLUDER 484

370 SMALL BUSINESS APPL 134

371 SMOKE SIGNAL BRDCSTG 51

372 SMOKE SIGNAL BRDCSTG (DEALERS ONLY) 61

374 SOFTSTAH CORP 413

376 SOFTWARE TECHNOLOGY 486

376 SOFTWARE-TO-GO 308

373 SOHO GROUP. THE 395

• SOLID STATE SALES 168

378 SOLID STATE SURPLUS 455

379 SORRENTO VALLEY ASSOC 389

380 SORRENTO VALLEY ASSOC 396

381 SOUTHERN SEMICNDTRS 299

382 SOUTHWEST TECH PROD C II

383 SP ELECTRONICS 488

384 SPECTRUM SOFTWARE 251

385 SSM MICRO COMP PROD 11

• STARBUCK DATA CO 417

386 STARSTRUCK SOFTWARE 467

388 STRUCTURED SYS GROUP 66

389 SUBLOGIC 74

390 SUMMAGRAPHICS 170

391 SUNNY INT'L 480

450 SUPER STAR INT'L CORP 271

■ SUPERSOFT 80,206,236,274, 275, 394

393 SYBEX1S9

■ SYNCHRO SOUND 412

394 SYNERTEK SYSTEMS 231

• SYSTEMS &SFTWRiNcne

396 SYS INTERFACE CONS 490

396 SYSTEMS PLUS 323

• TAB BOOKS 257

398 TARBELL ELECTR 393

399 TECHNICAL INNOVATIONS 484

400 TECHNICAL SYS CONS 77

401 TECMARINC296

406 TEI INC 318

407 TEI INC 322

408 TEI INC 324

402 TERCER MEDIO 331

403 TERMINAL DATA SYS 484

404 TEXAS COMP SYS 390 406 TEXAS INSTRUMENTS 105

409 THREE M COMPANY 66

410 THUNDERWARE 240

• TINNEY, RBT GRAPHICS 269

411 TINY-C30

412 TNW CORP 373

413 TOOLSMITH, THE 463 449 TOTAL DIGITAL ENG 374

414 TOTAL INFORMATION SVC488

415 TRADE-A-COMPUTER294

416 TRANSNET CORP 375

417 TSE/HARDSIDE 166

418 US MICRO SALES 496, 497

419 US ROBOTICS 369

420 UDO CORP 17

• UNITED SFTW AM 172. 173

421 URBAN SFTW CORP 402

422 VAMP INC 453

423 VANDATA409

424 VECTOR ELECTR 16 426 VECTOR GRAPHICS 129

426 VERBATIM CORP 79

427 VERTICAL DATA SYS INC 408

428 VIDEO MARKETING 486

429 VIDEX 287

430 VOICETEK 248

432 WS ELECTRONICS 457

■ WASHINGTON COMP SERV 487

• WESTICO INC 188. 189. 486

433 WHITE COMP SYS 33

434 WHITESMITH'S LTD 157

435 WILD HARE COMP SYS 166

436 WINTEK CORP 484

437 WINTERHALTER & ASSOC 112

438 WORLDWIDE ELECTR 455

439 WW COMPONENT SUPPLY 474 448 XPS INC 484

440 ZOBEX319

To get further information on ifie products advertised in BYTE, fill out the reader service card with your name and address. Add a 18-cenl stamp to the card, then mail. The index IS provided as an additional service by the publisher, who assumes no liabilily for errors or omlsstons.

512

May 1981 ® BYTE Publicatiaiu Inc

The Dynabyte Difference: Unequalled price/performance

with total expandability.

Buying the powerful Dynabyte 5615 isn't only smart,

ifs cost efficient.

The 5615 is the sure way to get the system you need. With more power for the price. You can select memory to 400 KB on our S-100 bus architecture. Choose from 3 sizes of Winchesters to 45 MB and have diskette backup to your system also. If it's tape back-up you need, then choose our 5700. If you need less storage, our 5^" floppy 5200, our 8" floppy 5300 or our 5400 system using both floppies, with up to 3.6 MB capacity, can be yours.

The 5615 system is available with either single user CP/M or our enhanced MP/M for multi-user applications. Our MP/M operating system supports up to eight terminals, with a separate or shared spooler, and up to sixteen printers with no required partition space. Add to this multi-tasking, bank switching, record lockout, type-ahead and DMA and you have an MP/M operating system that supports a host of existing languages and meets minicomputer standards.

No multi-user applications library is so responsive to your needs. The 5615 features Business Manager,™ the fully integrated, menu-driven, well documented, easy to install accounting system that gives you file/record protection, HELP commands, multi-level security, keyed data access, internal disk management, available source code and more.

System expandability, power and price/performance are further enhanced by on-hand availability, quandty discounts, 180-day warranty and a national WATS line for support.

Whether you use or sell computer systems, you should ask about the microcomputer that puts minicomputer capability in your hands. That's the 5615. That's the Dynabyte Difference. Call Mike Seashols.V P Marketing (800) 227-8300. In California (415) 329-8021. Dynabyte, 115 Independence Drive, Menlo Park, California 94025.

Business Manager is a registered trademark of Dynabyte. CP/M and MP/M are registered trademarks of Digital Research Corp.

Circle 139 on inquiry card.

A cost effective 10 megabyte system from tne leader

in Winchester based microcomputers.

Ohio Scientific has put a low-cost, high-performance 8" non-rennovable hard disk together with its popular desk-top microconnputer systenn. This yields approximately 10 megabytes of fast hard disk capability at a tremendous cost/performance benefit over floppy based microcomputer systems.

795y

C3-D

The 10 megabyte system is also available with the added advantage of triple microprocessors — the 6502A, 68BOO and Z-80A. This allows you to make maximum use of Ohio Scientific's extensive software library as well as programs offered by independent suppliers and publishers. $7,600.

C2-D ^ Standard Features

■ 52K RAM

■ 8" floppy disk drive for program transport and backup.

■ OS-65U small business operating system

■ 9-digit precision BASIC by Microsoft.

■ Available in OEM quantities at attractive discounts.

For literature and the name of your local dealer, CALL 1-800-321-6850 TOLL FREE.

a AjU^^n Company

1333 SOUTH CHILLICOTHE ROAD, AURORA, OH 44202 • [216] 831 -SBC

Circle 291 on inquiry card.