Byte Magazine Volume 06 Number 10 - Local Networks

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A new small computerthat won't limit you tomorrow

*

New Cromemco System One shown with ourhigh-capability terminal and printer.

M&m

Expandability

Here's a low-priced computer that won't run outof memory capacity or expandability halfwaythrough your project.

Typically, computer usage tends to grow, requir-ing more capability, more memory, more storage.Without a lot of capability and expandability, yourcomputer can be obsolete from the start.

The new System One is a real building-blockmachine. It has capability and expandability by thecarload.

Look at these features:

■ Z80-A processor

■ 64K of RAM

■ 780K of disk storage

■ CRT and printer interfaces

■ Eight S-100 card slots, allowing expansionwith

— color graphics

— additional memory

— additional interfaces for telecommunica-tions, data acquisition, etc.

■ Small size

GENEROUS DISK STORAGE

The 780K of disk storage in the System OneModel CS-1 is much greater than what is typicallyavailable in small computers. But here, too, youhave a choice since a second version, ModelCS-1H, has a 5" Winchester drive that gives you5 megabytes of disk storage.

MULTI-USER, MULTI-TASKINGCAPABILITY

Believe it or not, this new computer even offersmulti-user capability when used with our advancedCROMIX* operating system option. Not only does thisoutstanding O/S support multiple users on this com-puter but does so with powerful features like multi-

ple directories, file protection and record level lock.CROMix lets you run multiple jobs as well.

In addition to our highly-acclaimed CROMIX, thereis our cdos*. This is an enhanced CP/M+type systemdesigned for single-user applications, cp/m and awealth of CP/M-compatible software are alsoavailable for the new System One through third-party vendors.

COLOR GRAPHICS/WORD PROCESSING

This small computer even gives you the option ofoutstanding high-resolution color graphics with ourModel SDI interface and two-port RAM cards.

Then there's our tremendously wide range ofCromemco software including packages for wordprocessing, business, and much more, all usablewith the new System One.

ANTI-OBSOLESCENCE/LOW-PRICED

As you can see, the new One offers you a lot ofperformance. It's obviously designed with anti-obsolescence in mind.

What's more, it's priced at only $3,995. That'sconsiderably less than many machines with muchless capability. And it's not that much more thanmany machines that have little or nothing in theway of expandability.

Physically, the One is small — 7" high. And it's all-metal in construction. It's only 14Vb" wide, ideal fordesk top use. A rack mount option is also available.

CONTACT YOUR REP NOW

Get all the details on this important building-blockcomputer. Get in touch with your Cromemco repnow. He'll show you how the new System One cangrow with your task.

•CROMIX and CDOS are trademarks of Cromemco Inc.tCP/M is a trademark of Digital Research

rjj Cromemco

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

Tomorrow's computers today

Circle 108 on Inquiry card.

Management Information Display

Ultrasonic heart sector scan

Process Control

Get the professional color

display that hasbasic/fortran simplicity

LOW-PRICED, TOO

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

Basically, this new Cromemco ModelSDI* is a two-board interface that plugsinto any Cromemco computer.

The SDI then maps computer displaymemory content onto a convenient colormonitor to give high-quality, high-resolution displays (756 H x 482 V pixels).

When we say the SDI results in a high-quality professional display, we mean youcan't get higher resolution than thissystem offers in an NTSC-conformingdisplay.

The resolution surpasses that of a colorTV picture.

BASIC/FORTRAN programming

Besides its high resolution and lowprice, the new SDI lets you control withoptional Cromemco software packagesthat use simple BASIC- and FORTRAN-like commands.

Pick any of 16 colors (from a4096-color palette) with instructions likeDEFCLR (c, R, G, B). Or obtain a circle ofspecified size, location, and color withXCIRC (x, y, r, c).

•U.S. Pat. No. 4121283

Model SOI High-Resolution ColorGraphics Interface

HIGH RESOLUTION

The SDI's high resolution gives aprofessional-quality display that strictlymeets NTSC requirements. You get 756pixels on every visible line of the NTSCstandard display of 482 image lines. Ver-tical line spacing is 1 pixel.

To achieve the high-quality display, aseparate output signal is produced foreach of the three component colors (red,green, blue). This yields a sharper imagethan is possible using an NTSC-compositevideo signal and color TV set. Full imagequality is readily realized with our high-quality RGB Monitor or any conventionalred/green/blue monitor common in TVwork.

z-za

■ MM fafpRM

Model SDI plugs into Z-2H 11-megabyte

hard disk computer or any Cromemco

computer

DISPLAY MEMORY

Along with the SDI we also offer anoptional fast and novel two-port memorythat gives independent high-speed accessto the computer memory. The two-portmemory stores one full display, permit-ting fast computer operation even duringdisplay.

CONTACT YOUR REP NOW

The Model SDI has been used in scien-tific work, engineering, business, TV,color graphics, and other areas. It's agood example of how Cromemco keepscomputers in the field up to date, since itturns any Cromemco computer into anup-to-date color display computer.

The SDI has still more features thatyou should be informed about. So contactyour Cromemco representative now andsee all that the SDI will do for you.

Q CromemcoIncorporated280 BERNARDO AVE., MOUNTAIN VIEW, CA 94040 • (415)964-7400

Tomorrow's computers today

Circle 109 on Inquiry card.

In The Queue

Volume 6, Number 10

October ! 981

Features

ZO The IBM Personal Computer: First Impressions by Phil

Lemmons / The computer giant embraces software compatibility and support for in-dependent peripheral manufacturers.

3b Build an Intelligent EPROM Programmer by Steve Ciarcia

I Wilh a Z8-BASIC Microcomputer, you can easily put together a versatile programmerfor 271 6 EPROMs.

5U Ultra-Low-Cost Network for Personal Computers by Ken

Clements and Dave Daugherty / The age of communication for personal com-puters has arrived; don't be left behind.

#U The Atari Tutorial, Part 2: Graphics Indirection by Chris

Crawford / Graphics indirection lets you quickly change the colors used in the videodisplay and redefine the Atari character set.

J (L Local-Area Networks, Possibilities for Personal Computers

by Dr Harry J Saal / The "one person, one computer" concept is improved withcommunications.

1 1 *T Prepare Your Program for Publication by C A Johnson / A

checklist of professional touches that can make software sell.

126 Software Protection In the United Kingdom by Martin

Hayman / A London conference confronts the problem of software piracy.

I 4v Network Tools, Ideas for Intelligent Network Software by

Peter B Reintjes / A set of general modules provides a basis for networking.

176 A Simple Implementation of Multitasking by Wendell

Brown / A little SLEEP can go a long way.

195 Tree Searching, Part 2: Heuristic Techniques by Gregg

Williams / Admissible algorithms allow you to find an optimal solution without an ex-haustive search of the state-space tree.

214 Drawing with UCSD Pascal and the Hlplot Plotter by Dr

James Stork / Some UCSD plotting routines that can be linked to any Pascal program.

2 SO Evaluate Your Home's Energy Efficiency, Conserve Energywith Your Computer by Kimball Beasley / Use your computer to lower thosebudget-breaking heat bills.

264 Bridging the 10-Percent Gap by Paul T Brady / Software problemscan hold back a small-business data-processing explosion.

Zo4 Graphics Fundamentals by Kathleen Bresnahan Sandifur/A

company logo is the vehicle for understanding windows and scaling.

400 Build a Versatile Keyboard Interface for the S-100 by David

R Richards / A device that lets you communicate with your microcomputer

4w # PERT Organization by W Douglas Maurer / A mathematicalmethod used by computer programmers to determine the relative importance of thetasks under their supervision.

413 Should the DO Loop Become an Assembly-Language Con-struct? by Glenn L Williams / innovative instructions can forestall the "software

430 Multiple Regression for the TRS-80 by Douglas William

Madron / On converting the mathematics of linear regression into a general-purposeBASIC program,

448 Bits and Bytes In Pascal, and Other Binary Wonders by

David Casseres / Put UCSD Pascal through its paces to ease programming and havefun.

45B Apple Analog-to-Dlgltal Conversion In 27 Microseconds by

Michael A Seeds / Build this high-speed. 10-bit analog-to-digital converter for yourApple for less than S 100.

462 PS—A FORTH-LIke Threaded Language, Part I by Vafo G

Motalygo / PS allows assembly-language code and high-level code to be mixed.

Reviews

86 Atari's Telelink I by Glen Flint

378 Integral Data's Paper Tiger 460 by Eliakim Willner

383 The Mauro Proac Plotter by Mark Dahmke

385 The Radio Shack FORTRAN Package by Tim Daneliuk

Nucleus

610

122,

302

304

306

316

324

332

332,

342

356,

366,

372

471526527

528

EditorialLetters

278, 334, 354, 467System Notes: List Pager; Discoverthe Machine Beneath the Machine, A Z80 Monitor Pro-gram; A Closer Look at the TRS-80 Color Computer; TwoShort Graphics Programs for the OSI C-IP; Recursive Pro-cedures for the 6502 MicroprocessorSoftware ReceivedBooks ReceivedBYTELINESAsk BYTEEvent QueueClubs and Newsletters375 BYTE's Bits

Book Reviews: Four Roads to Understanding Radio Shack'sTRS-80

376, 419 Programming Quickies: Memory Manipulator.Eliminate Hex-a-Phobia; A Fast, Ancient Method forMultiplication; Apple Pascal Cross-Reference391, 394 Technical Forums: Use a Relative SubroutineCall for Relocatable Z80 Programs: The Variable-Duty-CycleAlgorithm; Dynamic Simulation in BASICLanguages Forum: BASIC, Pascal, or Tiny-c? A SimpleBenchmarking ComparisonWhat's New?Unclassified AdsReader ServiceBOMB, BOMB Results

BITE

Page 36

Page 70

Page 264

Page 400

October 1981 © BYTE Publications Inc 3

fffilH

Editor in ChiefChristopher Morgan

Managing Editor

Mark Haas

Technical Editors

Gregg Williams, Senior Editor;Richard S Shuford; Curtis P Feigel;George Stewart: Arthur Little;Stanley Wszola; Charles Freiberg.New Products Editor; Steve Ciarcia.Mark Dahmke. Philip Lemmons,Consulting Editors; Jon Swanson,Draftsman

Copy Editors

Beverly Cronin. Chief; Faith Hanson;Warren Williamson; Anthony J Lockwood;Ann Graves; Jane Harrigan;David R Anderson

Assistants

Faith Ferry; Debe Wheeler;Karen A Cilley; Susan Ferber

Production

Nancy Estle, Director; Christine Destrempes,Asst Director; Jonathan M Graves. CreativeConsultant; Wai Chiu Li; Patrice Scribner;Karen Labaugh: Damian Henriques;Jan Muller; Sherry McCarthy.Chief Typographer;Debi Fredericks. Donna Sweeney:Valerie Horn

Advertising

Thomas Harvey. Director; Marion Carlson;Rob Hannings; Marilyn Williams:Deborah Porter; Vicki Reynolds;Barbara Hoy; Jacqueline Earnshaw.Reader Service Coordinator

Circulation

Gregory Spitzfaden, Manager;Andrew Jackson. Asst Manager;Agnes E Perry; Barbara Varnum;Louise Menegus; Pinky Krulis;James Bingham. Dealer Sales;Carol Baniecki, Asst.

Controller's Office

Daniel Rodrigues, Controller;

Mary E Fluhr. Acct. & DIP Mgr; Karen Burgess;

Jeanne Cilley; Mary Beth Ireland; Linda Fluhr

Traffic

N Scott Gagnon; Michael Bacon;Cynthia Damato

Receptionist

Joanne Colburn

Publishers

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

Officers of McGraw-Hill Publications Com-pany: Paul F McPherson, President: ExecutiveVice Presidents: James E Boddorf, Gene WSimpson; Group Vice President: Daniel AMcMillan; Senior Vice President-Editorial: RalphR Schulz; Vice Presidents: Kemp Anderson.Business Systems Development; Robert B Doll,Circulation: James E Hackett. Controller; Eric BHerr, Planning and Development; H JohnSweger. Marketing.

Officers of the Corporation: Harold WMcGraw Jr. Chairman and Chief ExecutiveOfficer; Joseph L Dionne. President and ChiefOperating Officer; Robert N Landes, Senior VicePresident and Secretary; Ralph J Webb,Treasurer.

In This Issue

Local-area networks are a means of sharing information and resourcesamong many personal computers located within a relatively short distance ofeach other. As Robert Tinney's cover illustrates, each station in the network islinked physically to the others, but each also can operate independently. Thelocal networks themselves need not operate in a void; gateways can link themwith other networks thousands of miles away.

To expand on this month's theme, we present an assortment of articles, in-cluding "Local-Area Networks: Possibilities for Personal Computers," "Ultra-Low-Cost Network for Personal Computers," and "Network Tools—Ideas forIntelligent Network Software."

In addition, Steve Ciarcia helps you "Build an Intelligent EPROM Program-mer," and Martin Hayman discusses "Software Protection in the UnitedKingdom." We have "The Atari Tutorial, Part 2: Graphics Indirection," andC A Johnson advises on how to "Prepare Your Program for Publication." Ofcourse, you can also enjoy our regular features and much more.

BYTE is published monthly by BYTE Publications Inc. 70 Main St. Peterborough NH 03458. phone (603]924-9281. a wholly-owned subsidiary of McGraw-Hill. Inc. Address subscriptions, change of address. USPS Form3579, and fulfillment questions to BYTE Subscriptions. POB 590. Martinsville NJ 08836. Controlled circulationpostage paid at Waseca. Minnesota 56093 - USPS Publication No. 528890 (ISSN 0360-5280). Canadian secondclass registration number 932 i. Subscriptions are S19 for one year. S34 for two years, and S49 for three years inthe USA and its possessions. In Canada and Mexico. S21 for one year. S38 for two years. S 55 for three years. S43for one year air delivery to Europe. S35 surface delivery elsewhere. Air delivery to selected areas at additionalrates upon request. Single copy price is S2.50 in the USA and its possessions, S2.95 in Canada and Mexico, S4.00in Europe, and S4.50 elsewhere. Foreign subscriptions and sales should be remitted in United States funds drawnon a US bank. Printed in United States of America.

Address all editorial correspondence to the editor at BYTE. POB 372. Hancock NH 03449. Unacceptablemanuscripts will be returned if accompanied by sufficient first class postage. Not responsible for lost manuscripts orphotos. Opinions expressed by the authors are not necessarily those of BYTE. Entire contents copyright © 1981by BYTE Publications Inc. All rights reserved. Where necessary, permission is granted by the copyright owner forlibraries and others registered with the Copyright Clearance Center (CCC) to photocopy any article herein for thebase fee of S1.00 per copy of the article or item plus 25 cents per page. Payment should be sent directly to theCCC, 21 Congress St. Salem MA 01970. Copying done for other than personal or internal reference use withoutthe permission of McGraw-Hill is prohibited. Requests for special permission or bulk orders should be addressed tothe publisher.

BYTE® is available in microform from University Microfilms International. 300 N Zeeb Rd. Dept PR. AnrArbor Ml 48106 USA or 18 Bedford Row, Dept PR, London WC1R 4EJ England.

Subscription WATS Line: (800J 258-5485Office hours: Mon-Thur 8:30 AM - 4:30 PM, Friday 8:30 AM - Noon, Eastern Time

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October 1981 © BYTE Publications Inc

". . .stands well aboveother S-100 graphics dis-plays in its price and per-formance range."

". . . better monochromatic. . . display.

BYTE, Product Review

ELECTRONIC DESIGN,1981 Technology Forecast

MICROANCELO

HIGH RESOLUTION GRAPHICS SINGLE BOARD COMPUTER

512x480 resolution black and white and vivid color displays

RS-170 com-posite or direct

drive output

Local or externalsync generation

\ | -

4MhzZ80

microprocessor

■IY V

60 hertz real-

■ '

time clock

8 level interrupttie-in

IEEE S100 buscompatible

,:■■" --

... m" .... I

Ml«««iiiiiiiiiiiiiiiiiiiiiiffi;ii,S^i(

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Light peninterface

Time multi-plexed refresh

4K resident

Screenware™

Pak I operating

system

32KRAM

isolated from

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space

High speed

communications

over parallel

bus ports

Screenware™ Pak I

A 4K byte operating system resident in PROM onMicroAngelo™. Pak I emulates an 85 characterby 40 line graphics terminal and provides over40 graphics commands. Provisions exist for userdefined character sets and directly callable userextensions to Screenware™ Pak I.

Screenware™ Pak II

An optional software superset of Pak I whichadds circle generation, polygon flood, program-mable split screen for separate graphics and ter-minal I/O, relative coordinates, faster vector andcharacter plotting, a macro facility, full UCSDPascal compatibility, and more.

And now. ..COLOR!!

The new MicroAngelo™ Palette board treats from2 to 8 MicroAngelos as "bit planes" at a full512 x 480 resolution. Up to 256 colors may bechosen from 16.8 million through the program-mable color lookup table. Overlays, bit planeprecedence, fade-in, fade-out, gray levels, blink-ing bit plane, and a highly visual color editor arestandard.

SCION

Circle 328 on inquiry card.

12310 Pinecrest Road • Reston, VA 22091 • (703)476-6100 • TWX: 710-833-0684

Circle 122 on inquiry card.

TM

PLAN80

A powerful tool forplanning and analysis

I

Version 2.0 featuringGraphic Analysis

-4 + ^

PLAN80 is a modeling systemfor desktop computers... Easyto use yet capable of handlingmost timesharing applications.

With any familiar word processoryou can create models in termsthat make it easy to review as-sumptions and methods withothers. Anyone can create budg-ets, project sales, analyze cashflow or build a system of inter-related plans.

PLAN80 has the power of bigcomputer modeling systems andlets you

• Produce both tables andgraphs from same data

• Change assumptions andrecalculate results inseconds

• Prepare reports exactly toyour specifications

• Consolidate any part of onemodel into another

• Create models having up to4,000 cells

• Compute depreciation, inter-nal rate of return, or stepfunctions using table lookup.

PLAN80 requires 56K, CP/M anda Z80 or 8080 micro. Also availa-ble for CP/M-86. Price is $295.Manual alone-$30.

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CP/M & CP/M-86 trademarks Digital Research

Editorial

Local NetworksAre Buzzing

by Chris Morgan, Editor in Chief

Buzzwords are a way of life in the computer industry, and the latest buzz-word (or, to be more correct, buzz-phrase) among computer cognoscenti is thelocal network. Networks in one form or another have been with us for sometime. IBM's SNA network and the X25 public network from ISO (InternationalStandards Organization), used by Tymenet and Telenet, are systems designedto transmit huge amounts of data over long distances. But recently a wholenew industry has sprung up to serve personal computer owners who want tosend electronic mail or share the other resources of a local network.

This month we present several articles about local networks, including onewritten by Harry J Saal, President of Nestar Systems Inc, called "Local-AreaNetworks: Possibilities for Personal Computers." It's an excellent overview oflocal networks, their history, and the current state of the art. Much of the im-petus behind the blossoming local-network field comes from Ethernet, Xerox'shigh-end local network system that can transmit up to 10 megabits persecond (Mbps) of information between users. You may have seen the recenttelevision advertisements for the Ethernet system.

Although Ethernet works well for large-scale systems employing minicom-puters or mainframes, it's a case of overkill for microcomputers, which haveinherent speed limitations. Two local network schemes, both patterned in oneway or another after Ethernet, now exist to serve the microcomputer market.One such network, made by Nestar, is described in detail by Dr. Saal. Theother is a relative newcomer — Corvus's Omninet.

Comparing Two Systems

While the Nestar system, officially called the Cluster/One Model A, isdesigned exclusively for use with Apple II computers, the Omninet systemallows users to mix and match such computers as the Apple II, Radio Shack'sTRS-80, the Onyx, and computers using the LSI-11 processor and the S-100bus.

The data-transfer rate of the Omninet system is 1 Mbps, compared withNestar's 240 kbps. Although Omninet is technically four times faster than theNestar system, the numbers can be misleading because the actual amount oftime spent transmitting or receiving data to and from the network usuallyrepresents only a fraction of the total computing time. Recent tests by Xerox ofthe Ethernet system bear out these results.

Of more importance to the average user is the network's reliability and howeasy it is to use. The Nestar system has been around for more than two yearsand has earned high marks for reliability and sophistication. It's particularlywell suited to classroom use, and I have seen the system at work in manyschools around the country. The Omninet system is just beginning to appearon the market, and we plan to review it in detail in a future issue of BYTE.Aside from its ability to handle a variety of computers, Omninet also offersthe attraction of low price. The hardware cards for the Apple II, TRS-80, and

October 1981 © BYTE Publications Inc

New! Z Controller and Z Drives . . .

Expect more from Percom. You won't be disappointed.

Percom's double-density Z Controller for the H-89 isnow available.

Check its many outstanding features.

And keep in mind its from Percom, a companythat introduced its first disk system in 1977.

• Controls up to four single- or double-headed mini-disk drives.

• Handles 35-, 40-, 77- and 80-track drives, and other standardtrack densities. • Formatted data storage capacity of 80-track dis-kettes is over 368 Kbytes. Forty-track diskettes store over 184Kbytes. Capacities for other track densities are proportional. A Zsystem with four double-headed, 80-track drives provides almost3 megabytes of on-line data. • The Z Controller co-resides withyour H-89 disk drive controller. Your software can select either,and you don't have to move drives around when switching be-tween systems. • The Z Controller includes Percom's proven dig-ital data separator circuit and a dependable write-precompensationcircuit. Expect reliable disk operation for a long, long time under 'Z'control. • The Percom Z Controller is priced at only $249.95, com-plete with HDOS-compatible disk drivers on diskette, internal inter-connecting cable and comprehensive users manual.

System requirements — H-89 Computer with 24 Kbytes memo-ry (min). Replacement ROM Kit H-88-7 and HDOS 2.0.

Add-On Z Drives for H-89, H-8 Computers

• Forty- and eighty-track densities in either 1- or 2-drive modules.

• All drives are rated for single- and double^densiry operation. Witha Z Controller, an 80-track drive can store over 364 Kbytes (for-matted, one-side), a 40-track drive can store over 184 Kbytes.

• Some models permit "flippy" storage, letting you flip a disketteand store files on the second side. *Z drives are fully tested, includ-ing a 48-hour operating burn-in to prevent shipment of drives withlatent defects. • Assembled and tested one-drive units from only$399, two-drive units from only $795.

System requirements - H-89 or H-8 computer with 16-KbyteRAM, Heath first-drive floppy disk system, HDOS and drives inter-connecting cable. (Two-drive interconnecting cable optionallyavailable from Percom)

PRICES AND SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE.

Watch for announcement of 'Z' CP/M.

PEfiCDM

PERCOM DATA COMPANY, INC.211 N. KIRBY GARLAND, TEXAS 75042

(214) 272-3421Toll-Free Order Number: 1-800-527-1592

S 1981 PERCOM DATA COMPANY. Inc.

PERCOM. ZFD 40 and ZFD-80 are trademarks of Percom Data Company.

CP/M is a trademark ol Digital Research Corporation.

Yes ... I'd like to know more about Percom Z drives and theZ Controller. Rush me free literature.

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Pascal/Z is a true Pascal. It closely follows the Jensenand Wirth standard with a minimum of extensionsdesigned to aid the serious program developer inproducing extremely compact, bug-free code thatruns FAST.

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Editorial.

S-100-type computers cost less than $500 each, meaningthat two interested networkers could assemble a minimaltwo-node network for less than $1000. The only addi-tional cost is for the twisted-pair wiring used to connectthe two computers. No central control computer isneeded to run the network.

Data is transmitted on the Omninet in blocks of ASCIIcharacters using software tools called pipes, reminiscentof the pipes used in the UNIX operating system butoperating in a different manner. In this way, machineshaving incompatible operating systems (such as CP/Mand UCSD Pascal) can communicate, albeit with somelimitations.

Comparing Nestar and Omninet is like comparing theproverbial apples and oranges (pun intended). Omninetis attractive for entry-level users, and it's the only choiceif you want to combine various brands of computers.Although rumor has it that Nestar is expressing an in-terest in other brands of computers besides Apple, thecompany has made no official statement on the subject.

Nestar has its own advantages, including its excellenttrack record. The file server used in the Nestar system isactually an Apple II computer, which can act as a spare ifneeded in the system. Also, Nestar offers extensive andwell-documented software. The Nestar system requires16-conductor ribbon cable for computer interconnection,compared with twisted-pair wire for the Omninet — acost saving for the Omninet user.

Corvus is actively promoting Omninet as an industrystandard for microcomputers. Onyx already has boughtan Omninet license, and the Japanese are reportedly in-terested in the network. (I recently saw a very interestinghobbyist-designed local network system at the offices ofASCII magazine in Japan. We hope to tell you about thatin a future issue.)

Siggraph '81

As I write this, the '81 conference of Siggraph (theACM's special interest group for computer graphics) is infull swing in Dallas, and it's a winner all the way. KenLivingston (who, with Mark Dahmke, reviewed Siggraph'80 for us last year) is on hand again, and his full reportwill appear later this year in BYTE. Without trying tosteal Ken's thunder, I must say that never before have Iseen such exciting portents for the future of computergraphics as I've seen in the last few days at this con-ference. The demonstrations of the latest computeranimation left all previous efforts in their wake.

The roster of attendees includes just about everyonedoing meaningful work in the computer graphics field. Iwish continued success to Siggraph, and I hope many ofour readers can attend Siggraph '82, to be held in Bostonnext summer. For more information, write to ElaineSonderegger, Siggraph '82 General Chairman, at POB353, Derby CT 06418. ■

Circle 185 on inquiry card.

The ultimate single user machine

The PDS-80™ with Cache BIOS™ is aprofessional system designed for themost rigorous single user CP/M*environments... in business, softwaredevelopment, scientific, educationaland industrial research... wherespeed and program space are criticalfactors.

SymBIOSis quadruples speed

No matter what high-level languageyou use... Cobol, Basic, Fortran,PL/1, or Pascal... PDS-80 offers morespeed, power and reliability than anyother floppy based CP/M systemcurrently on the market. TheInterSystems Cache BIOS fullyexploits the advanced DMA andinterrupt features of our reliableSeries II hardware to buffer wholetracks in extended memory so mostoperations run two to four timesfaster than on other floppy basedsystems ... actually equals the speedof many small hard disk systems.And Cache BIOS also provides manysophisticated system test andprotection features to assure reliableoperation.

An advanced CP/Mapplication system

PDS-80 has all you need forcommercial systems integration andapplications software development...including a choice of the industry'sonly integral 8 bit front panel. Best ofall, PDS-80 allows the systemsintegrator or applications developeraddressing a vertical market todevelop on the same components heconfigures for resale. The highlyexpandable modular design with

20slot S-100 mainframe allows almostunlimited options to suit any end useenvironment... including a choice oftabletop or rackmount design.

InterSystems will work with you atwhatever level is appropriate toconfigure the target system you need... right up to fully assembled andtested systems with floppy andWinchester disk drives.

Full software support

In addition to InterSystems' CacheBIOS and the CP/M operatingsystem, models of PDS-80

can include

L J Pascal/Z,

our highly acclaimed Z-80® nativecode Pascal compiler, and InterPak80™, a special set of utilitiesincluding a powerful screen editorand versatile spelling editor to assistin the rapid editing, proofing anddocumentation of your code. Thesepowerful programming aids are alsoavailable as standalone products.

It's upgradeable!

Both hardware and software aredesigned to provide for upgrade to 16bit operation. Programs written forPascal/Z are fully compatible withI-Pas 8000™, our Z-8000® native codecompiler, and all PDS-80 systems areupgradeable to our 16 bit multi-userDPS-8000.

We build micros for bigger ideas.

Your big ideas. We're dedicated toproviding the computer professional... Systems Integrators, commercialprogram developers, scientific andindustrial programmers ... withprofessional hardware and softwaretools. And we support our customersto the fullest, with complete,professional documentation,application engineering consultation,and prompt, responsive service bothfrom the factory and through factory-authorized service centers.

Call us toll free: 800-847-2088

for completeinformation on anyof our 8 or 16 bitsystems andsoftwareproducts

Distributor

Inquiries

Invited

ODDfeD&^feDDu^

\r Ithaca Intersystems Inc

Circle 185 on Inquiry card.

i Intersystems I

Micros for bigger ideas.

Ithaca Intersystems Inc. • 1650 Hanshaw Road • Ithaca, NY 14850 • Phone (607) 257-0190 • TWX: 510 255 4346U.K. Distributor Ithaca Intersystems (U.K.)Ltd. Coleridge Road London N8 8ED Phone: 01-341 2447 Telex: 299568

"Z-HU and Z-8000 are registered trademarks ol'Zilog, Inc. "Trademarks of Ithaca Intersystems Inc. 'Registered trademark of Digital Research

Letters

Clearing Waveforms

I enjoyed reading Robin Moore's article"Mountain Computer's MusicSystem"(July 1981 BYTE, page 60). There may besome confusion, however, about the waythe Casheab synthesizer handles wave-form storage. With the Casheab syn-thesizer, waveforms are stored on the syn-thesizer cards and not in the hostmemory. This was done for three reasons:

• The Casheab synthesizer uses 1024words by 12 bits for each of its 16waveforms. This requires 25 K bytes ofmemory, which would be a considerablechunk of memory space if the waveformswere stored in the host's memory space.

• When the waveforms are stored in thehost's memory, processor time is going tobe required to transfer them to the syn-thesizer. The MusicSystem uses DMA(direct memory access), which is probablythe most efficient way to make the trans-fer. However, this effectively slows theApple's processor from 1 MHz to 500kHz.

• It is much easier to add more channels toa system by adding another synthesizercard set when the waveform tables are notin the host memory.

Ceasar Castro

Casheab

5737 Avenida Sanchez

San Diego CA 92124

Unsung Marketer

While I thoroughly enjoyed the recentarticle entitled "The Japanese ComputerInvasion," I would like to go on the recordto correct some misleading informationthat appeared in the section regardingHitachi on page 212, beginning with thethird paragraph. (See the August 1981BYTE.)

Mr Miastkowski is correct in statingthat there is no Hitachi marketingorganization in the US (for large-scalecomputers, that is, a qualification thatshould have been included) nor anymovement toward developing one. How-ever, to call this a "major problem" totallyignores Hitachi's satisfaction with the jobbeing done by National Advanced Sys-tems (NAS). "Lack of a US organization"has not "hurt" sales of the AS/9000. In-deed, NAS has doubled the sales rate of its

predecessor and is progressing very well inAS/9000 penetration.

Mr Miastkowski also states that Hitachiintroduced the AS/9000. This is incorrect.NAS introduced the AS/9000, its redesignof the Hitachi M200H.

It is also incorrect to characterize NASas a company "with (merely) a largeamount of small-computer experience." Inthe 303X class and upward, NAS has 276systems installed, hardly a lack of ex-perience. If one includes MVS-classmachines (which are generally considerednot to be "small" systems), the numbergoes to about 600! And, in the "H" class,the subject of the paragraph, we havemore experience than either IBM or Am-dahl (i.e., we're shipping and they aren't)!

Lastly, Miastkowski refers to the"strange bug" which occurred at LockheedDialog and implies that service is a majorproblem. This is absolutely untrue.Specifically, a problem arose in the chan-nel check logic in which the software wasunable to recover from a channel check.Investigation revealed that, while theAS/9000 channel interfaces were designedto published IBM specification docu-ments, IBM had subsequently changed (inthis case, loosened) the parametersgoverning the timing of the counting ofparallel bits. We immediately applied anEC retiming the parameters and retro-fitted all other AS/9000s. The incident, infact, illustrated the expertise of ourengineers in solving a problem we did noteven create and in solving it in recordtime.

David GoldsmithDirector—Sales SupportNational Advanced Systems800 E Middlefield Rd,Mountain View CA 94043

On Old Ad Age

As a mechanical engineer, I have hadBYTE save my neck by letting me knowwhat to expect from the "SiliconWonders" before other engineers. But Iwould like to share some observationsabout BYTE that I have made over the lastfive years.

BYTE has evolved from a magazine of"hobbyists" into a leading and respectedtechnical journal. As such, the reader isassumed to have sufficient technical ex-pertise to read and assimilate the infor-

mation presented. To my knowledge, thisassumption has turned off a number ofpotential subscribers. It shouldn't be toodifficult to publish a yearly "Beginner's In-tro" issue of BYTE which could be in-cluded with every new subscription. Itcould educate and entice new subscribers,while the "old-timers" shouldn't objecttoo strenuously to a yearly review ofbasics (who knows, it might even help). Itwould definitely help overcome the shockto a neophyte who wants to learn aboutthe nitty-gritty of computers and picks upa BYTE only to be deluged with "comput-erese" and articles that go over his or herhead in the first paragraph.

A good portion of each BYTE isdevoted to advertisement. I am not com-plaining. In fact, I have learned almost asmuch about computers from the ads asfrom the articles. But I currently haveabout 30 inches of bookshelf devoted toBYTE and, if the advertisements could beremoved, that could be cut down to 20inches or less! An advertisement that's ayear or more old is of little value to me,but articles that age are very valuable tome. What I suggest is to bind the articlesin one group that can be removed forfiling. They could be preceded by the"prestige" ads and followed by the bulkads. I doubt that this change in formatwould reduce the effect of advertising inBYTE since most of BYTE readers that Iknow either read every ad in each issue orignore them. It would reduce the space re-quired to archive back issues consider-ably. (I'd like to see this idea catch onbecause I currently have over 15 feet ofbookshelf dedicated to my technical jour-nals and it's growing daily!)

Lew Merrick19217-28th Ave WLynnwood WA 98036

Our "potential subscribers" who areturned off by our technical level sliouldtake a look at our new sister publication,Popular Computing. . . . MH

Legal Arguments

As an attorney, computer enthusiast,and coauthor of a recently publishedbooklet entitled "The Copyright Kit—How to Copyright Your Computer Soft-ware," I feel I must clarify two pointsraised by Stephen Becker in his article

10 October 1981 © BYTE Publications Inc

A Busload from SSM.

/ /

/ 71

'' H\

80 Character Video

With 80 characters perline our VB3 is the perfectvideo interface for word pro-cessing. It produces a standard80x24 display of upper andlower case characters or asmuch as 80x50 for a full pageof text. The matrix for graphicdisplay goes up to 160x200.And with optional EPROM,as many as 256 user program-med characters or symbols canbe produced.

VB3 is memory mappedfor rapid screen updating. Butit occupies memory only whenactivated. So one or moreVB3s can be located at thesame address with a full 65Kof memory still available tothe user.

It generates both U.S.and European TV rates andmeets IEEE 696.1 standard.Other features include key-board input, black on white orwhite on black, one level ofgrey, underline, strike thru,blinking char., blank-outchar., and programmable cur-sor. Software includes aCP/M compatible driver and apowerful terminal simulator.

-80 CP

We spent over a year de-signing the CB2 to assure thatit is the most fully S-100 com-patible Z-80 CPU on themarket.

It operates at 2MHz or4MHz by DIP switch selectionand includes two sockets for2716/2732 EPROMs or 2KRAMs. Memory sockets canbe disabled. Separate run/stopand single step switches allowsystem evaluation without thebenefit of a front panel.

CB2 also features anMWRITE signal, firmwarevector jump, and an outputport to control 8 extended ad-dress lines (allowing use ofmore than 65K of memory).Jumper options generate thenew IEEE 696.1 signals.

New SSM Products.

Please call for all the latest details on our newest products:

• MB 64 64Kb static RAM memory.

• 105 two parallel, two serial input/output ports, with com-

plete RS-232 protocol.

• 108 multiple RS-232 serial I/Os.

„080 CPU

Our CB1A is identical toour popular CB1 with the ex-ception that the on-boardRAM has been increased from256 bytes to a full IK.

It also features an op-tional 2K of 2708 EPROMs,power-on/reset vector jump.MWRITE, parallel input portwith status and DIP switchaddressing.

Our S-100 line includes CPU,Video, I/O, 8 and 16 BitRAM, EPROM, EPROM

Programmer, Prototyping,Terminator, Extender, andMother boards. Availableassembled or as kits.

SSM Microcomputer Products, Inc.

2190 Paragon Drive, San Jose, CA 95131, (408) 946-7400 Telex: 1'

71, TWX: 910-338-2077

Circle 348 on inquiry card.

Reddy Chirra improves his vision withan Apple*

Reddy is an optical engineer who sused to working for big companies and using bigmainframes.

But when he started his own consultingbusiness, he soon learned how costly mainframetime can be. So he bought himself a 48K Apple IIPersonal Computer

And, like thousands of other engineersand scientists, quickly learned the pleasures of

cutting down on shared timeown tamper-proof data base.

His Apple can handleformulas with up to 80 vari-ables and test parameters on250 different optical glasses.

He can even use BASIC, FORTRAN,Pascal and Assembly languages.

And Apple s HI-RES graphics come inhandy for design,

Reddy looked at other microcomputers, butchose Apple for its in-depth documentation,reliability and expandability.

You can get up to 64K RAM in an Apple II.Up to 128K RAM in our new Apple III, Andthere s a whole family of compatible peripherals,including an IEEE-488 bus for laboratoryinstrument control.

Visit your authorized Apple dealer to findout how far an Apple can go with scientific/technical applications.

It'll change the way you see things.

The personal computer^^KipplCZ

for the authorized dealer nearest you, call (800) 538-9696. In California, call (800) 662-9238. Or write: Apple Computer Inc., 10260 Bandley Dr., Cupertino, CA 95014.Circle no. 28 for more information or Circle no. 425 for special OEM information

Letters.

"Legal Protection for Computer Hard-ware and Software." (See the May 1981BYTE, page 140.)

Mr Becker tells us that he does notrecommend that his clients copyright (i.e.,register) their software until an infringe-ment suit is contemplated. My advicewould be just the opposite.

Section 412 of the 1976 Copyright Actspecifically disallows statutory damagesand attorneys' fees for any infringementof copyright commenced after first publi-cation of the computer program if it wasnot registered within three months afterthe first publication of the work. Thismeans that by not registering a computerprogram within three months of publica-tion, you lose possibly important dam-ages for infringement. For $10 (the cost ofregistration), I feel a computer programshould be registered at the earliest possiblemoment.

Mr Becker also states that two copies ofa computer program must be filed withthe Copyright Office along with form TXfor registration. In fact, the Rules andRegulations of the Copyright Office (Sec-tion 202.20 (c) (2) (vii) Code of FederalRegulations) provide that for a computerprogram published only in the form ofmachine-readable copies (such as mag-netic tape, disk, punch card, or the like)from which the work cannot ordinarily beperceived except with the aid of a ma-chine, the deposit need only consist of onecopy of the first and last 25 pages of theprogram printout together with the pagewhere the copyright notice appears.

I hope these corrections, in part, clarifyfor BYTE readers a complex area of the law.

Noel D Adler

14 Longacre Ct

Port Jefferson NY 11777

Stephen Becker Replies

/ stand by my advice. Mr Adler's state-ment that "Section 412 of the 1976 Copy-right Act specifically disallows statutorydamages and attorneys' fees for any in-fringement ..." tells only part of thestory. In fact, the 1976 Copyright Actspecifically provides for statutory in-fringement occurring after registration,■whether or not registration occurs withinthree months after first publication of thework.

Ideally, each program should be regis-tered as soon as possible. Copyright regi-stration of a program is neither as com-

plex nor expensive as patenting. It can,however, be burdensome to register eachprogram, particularly if you are develop-ing a substantial amount of new software.Each registration requires, besides the $10registration fee and attorney's fees (if oneis retained), deposit of a copy of the firstand last 25 pages of the program printouttogether with the page where the copy-right notice appears if the program is pub-lished only in machine-readable form, asMr Adler notes; otherwise, two completecopies of the program must be deposited.As a practical matter, however, thesoftware supplier will probably becomeaware of any infringement fairly soonafter it occurs. The infringer will be liablefor statutory damages and attorneys' feesfor all infringements following registra-tion. If the registration occurs within threemonths from the first publication date,the infringer will be liable even during thethree-month intervening time period.Even before registration, the courts havethe discretion to allow recovery of the in-fringer's profits to the software developerand may even require that royalties bepaid.

BYTE's Guide Praised

My wife and I wish to thank BYTE forincluding Mister McGiddies Creations Ltdin "The BYTE Guide: NCC Chicago." (Seethe April 1981 BYTE, page 64.) It is nice tobe recognized for all the work we havedone to promote the best in Bluegrassmusic in Chicago, while serving high-quality food at a good price.

McGiddies is now computerized by a48 K-byte Radio Shack TRS-80 Model Iwith multiple disk drives, Scripsit, and thePaper Tiger 460 printer. Without apublication like BYTE, the informationthat I would need to learn how to use acomputer in small business would not beavailable. I can actually say the computerhas put some fun back into paperwork,and, of course, the games are always fun.

Thank you, BYTE. Keep up the goodwork.

Hal and Sharon BergerPresident and Vice PresidentMister McGiddies Creations Ltd2423 N Lincoln AveChicago IL 60614

Quality Percom products are availablefrom the following authorized Percomretailers. If a retailer is not listed for yourarea, call Percom toll free at 1-800-527-1592 for the address of a nearby retailer,or to order directly from Percom.

ARKANSAS

MICROCOMPUTER SYSTEMS. INC. Hoi Springs (501) 623-5209

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CALIFORNIAALPHA BYTE STORES Calabasas (213)883-8594

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COMPUTER INFORMATION EXCHANGE

San Luis Rey (714)757-4849COMPUTER SERVICE CENTER Hollywood (213)8513434

DESMAR ELECTRONICS Santa Clara (408) 9882208

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WHOLESALE TECHNOLOGY SantaAna (714)9791700

COLORADOMICROCOMPUTER APPLICATIONS

Denver (303)922-6410

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Ormond Beach (9041673-5787MICROSYSTEMS SOFTWARE. INC.

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IDAHOOFFICE MAGIC COMPUTERS Boise (208)376-1613

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CARDENS, INC. Hutchinson (316)669-8261

MASSACHUSETTSOMNITEK Tewksbury 1617)8514580

MARYLANDDAMASCUS RADIO SHACK Damascus (301)253-2101

MICHIGANALTERNATE SOURCE Lansing (517)487-3358

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NEW HAMPSHIREHARDSIDE Millord (800)258 1790

NEW JERSEYCHANNEL 1 RADIO SHACK Medlord (609)654 7454

NEW MEXICOAUTEL ELECTRONICS Albuquerque (5051255-6451

NEVADAPCS COMPUTER Las Vegas (702)870-4138

NEW YORKH&ECOMPUTRONICS Spring Valley (914)425-1535

80 MICRO COMPUTER SERVICES Cohoes (518)235-9007

MICRO 80 SYSTEMS Brooklyn (212)748-3236

STONYCLOVE NewYorkCity (212)391-8337

OHIOFELDMAN ENTERPRISES Akron (216)724-5583

JERRY'S COMPUTER Cleveland (2161641-6719

MPS Wadsworth (216)336-2771

PENNSYLVANIAADVANCED MECHANIZATION Ivyland (215)672-9000

COMPUTER ANALYSTS New Brighton 1412)846 9323

TENNESSEECOMPUTER WORLD, INC. Nashville (615) 255-8330

MARKETING COMMUNICATIONS Memphis (901)794-8677

TEXASACCESS UNLIMITED Richardson

(800)527-3475(214)690-0206(713)488-8022(214)484-2976(915)577-2931

(801)298-6809

(414)281-7004

COMPUTEX Webster

QUALITY SOFTWARE Dallas

TEXAS COMPUTER SYSTEMS Brady

UTAHMICRO MNEMONICS Sunset

WISCONSINBYTE SHOP MILWAUKEE Greenfield

FOREIGN DEALERSAUSTRALIA

DICK SMITH ELECTRONICS P.O. Box321 North Tyde NSW2113

CANADAVALERIOTE AND ASSOC. Guelph Ontario (519)824-7041

DVR ELECTRONICS Surrey B.C (604)576 1045

MEXICOCIBERMATIC. S.A. Mexico (905) 592-3433

COMPUTADORAS Y ASESORAMIENTO

Rio Panvco 14 Mexico 5 D.F.DOMINICAN REPUBLICRADIOSHACK SantoDomingo (809)5659121

14

October 1981 © BYTE Publications Inc

Introducing the Z Line . . .

Now! Percom Drives for Heath Computers.

Percom's now making add-on drives for your H-89and H-8.

Complete drive systems will be available soon.

If your immediate need is for add-on storage,check the features of our fully compatible Z drives.

If you plan to add a complete disk system, watchfor the imminent announcement of our double-density Z Controller.

Given a choice, we think you'll choose from thePercom Z line.

Add-On Z Drives

• Available in 40- and 80-track densities, in 1- and 2-drivecolor-compatible modules.

• All drives are rated for single- and double-density oper-ation.

• Some models accommodate flippy storage, allowingyou to flip a diskette and store files on the second side.

• Fully tested both electrically and mechanically. Plus, all Zdrives receive a 48-hour operating burn-in to uncoverlatent defects. Look for the signed quality assurance slip.

• Low prices: Fully assembled and tested, one-drive unitsstart at only $399, two-drive units from only $795.

Z DRIVES FROM PERCOM: THE BEST ONES FOR YOUR ALL-IN-ONE

Mode]

NumberTracksone side

FormattedStrg. Cap.

SD

DD

ZFD-40"ZFD-80'"ZFD-100'"

408040

102K205K102K

180K364K180K

Low price, fast step timeMax. stg., fast step timeFlip-side diskette storage

SYSTEM REQUIREMENTS: H-89 or H-8 computer with 16 Kbytes of RAM,Heath first-drive floppy disk system, Heath disk-operating system and drives in-terconnecting cable. (Two-drive interconnecting cable optionally available fromPercom). ZFD-80 drives include a program patch on diskette to modify HDOSfor 80-track operation.

PRICES AND SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE.

Available Soon!Percom's Low-Cost Double-Density Z Controller.

PERCOM DATA COMPANY. INC.

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

Toll-Free Order Number: 1-800-527-1592

c 1981 PERCOM DATA COMPANY. Inc

PERCOM. ZFD-40. ZFD-80 and ZFD-100 are trademarks ol Percom Data Company.

Yes ... I'd like to know more about Percom Z drives and theZ Controller. Rush me free literature.

Send to

PERCOM DATA COMPANY, Inc., Dept. 26

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TWELVE STRONGHEATH/ZENITH YOUR

Pick a strong partner

A computer purchase is the beginning of a long termpartnership between you and the people you buy from.Your ongoing need for software and accessories re-quires a partner who will stand by you with a growingline of products. And nowhere will you find a more com-plete line of hardware, software and accessories thanat your Heathkit Electronic Center. Here are twelvestrong reasons to make Heath/Zenith your partner.

1. The All-in-One Computer

The heart of the Heath/Zenith line is the stand-alone89 Computer. It's a complete system with built-in 51A-inchfloppy disk drive, professional keyboard and keypad,smart video terminal, two Z80 microprocessors, andtwo RS-232C serial I/O ports. It comes with 16K RAM,expandable to 64K.

2. Peripherals

These include the popular Heath/Zenith19 Smart Video Terminal, loaded withprofessional features. And the 14 LinePrinter, priced as low as $495. Otherprinter brands are on display,including high-speed, typewriter-^quality printers.

3. Software

Word processing, includes reliable, easy-to-use

Zenith ElectronicTyping and powerful, full-featured

WORDSTAR.

Small Business Programs, feature General Ledger and

Inventory Control.

HUG, Heath Users' Group, offers members a library ofover 500 low-cost programs for home, work or play.

4. Programming Languages

For your own custom programs,Microsoft languages areavailable in BASIC (compilerand interpreter), FORTRANand COBOL.

5. Operating Systems

Three versatile systems give you the capability to per-form your specific tasks.

CPIM by Digital Research makes your system com-patible with thousands of popular CP/M programs.UCSD P-System with Pascal is a complete programdevelopment and execution environment.HDOS, Heath Disk Operating System gives you asophisticated, flexible environment for programconstruction, storage and editing.

6. Utility Software

Expand the performance range of your computer witha broad selection of utility tools, including the best ofDigital Research and the complete line of innovativeSoftstuff products.

7. Disk Systems

The 8-inch Heath I Zenith 47

Dual Disk System adds over 2

megabytes of storage to your

89 Computer. Diskettes are

standard IBM 3740 format, double-sided,double-density.

The 5Vt-inch 87 Dual Disk System adds200K bytes of storage to your 89. Bothdisk systems feature read/write protec-tion and easy plug-in adaptability.

8. Self-Study Courses

Learn at your own pacewith ProgrammingCourses that teach youto write and run your ownprograms in Assembly,BASIC, Pascal orCOBOL

A course on Computer Conceptsfor Small Business gives youthe understanding to eval-uate the ways a computercan benefit your business.Personal Computing is acomplete introduction tothe fundamentals forthenovice. Every Heathkit/Zenith course is pro-fessionally designedfor easy, step-by-step learning.

All Heath/ZenithComputer Productsare available completelyassembled and tested forcommercial use. Or in easyto-build, money-saving kits

REASONS TO MAKECOMPUTER PARTNER

9. Expansion Options

Communicate with the outside world through a Three-port EIA RS-232C Serial Interface.Expand RAM to 64K with easy-to-install expansionchips.

Accessories

Your Heathkit Electronic Center has the

latest in modems, black-and-white andcolor video monitors, computer furnitureand a full line of supplies, accessories, booksand parts.

11. Service

No one stands by you like Heath/ZenithWe help you get your system up andrunning smoothly. Service is avail-able from trained technicians,over the phone or at one of 56Heathkit Electronic Centers.

12. Value

Your money buys you more becauseHeath/Zenith prices are among the industry's mostcompetitive. Make your own comparison and find outhow much you can save.

Complete, integrated computer hardware and soft-ware, designed to serve you and to grow with you- that's what to look for in a strong partner. Andwith Heath/Zenith you get it all underone roof.

All at yourHeathkit ElectronicCenter

Pick the store nearest youfrom the list at right. Andstop in today for a demon-stration of the Heath/Zenith89 Computer System. If youcan't get to a store, send$1.00 for the latest Heathkit®Catalog and the new ZenithData Systems Catalog ofassembled commercialcomputers. Write toHeath Co., Dept. 334-827,Benton Harbor, Ml 49022.

Visit Your Heathkit Electronic Center*

where Heath/Zenith Products are displayed, sold and serviced.

PHOENIX,AZ

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ANAHEIM, CA

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395 W. Main St. (Rt. 44)

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404-252-4341

CHICAGO.IL

3462-66 W.Devon Ave.312-583-3920

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224 0gdenAve312-852-1304

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2112 E. 62nd St.317-257-4321

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1900 Veterans

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1713 E. Joppa Rd.

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R0CKVILLE.MD

5542 Nicholson Lane

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242AndoverSt.

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165 Worcester Ave.

617-237-1510

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18645 W. Eight Mile Rd.

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9207 Maple St.

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1013 State Hwy. 35

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35-07 Broadway (Rt. 4)

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15 Jericho Turnpike

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937 Jefferson Rd.

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28100 Chagrin Blvd.

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2500 Morse Rd.

614-475-7200

TOLEDO, OH

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Letters.

Comments on VIC

I recently evaluated the specifications ofvarious personal microcomputers now onthe market, so I noticed a couple of errorsin Gregg Williams's comparison of Com-modore's new VIC 20 to other microcom-puters. (See 'The Commodore VIC 20Microcomputer," May 1981 BYTE, page46.)

Mr Williams stated that the VIC is theonly machine in which "the backgroundcolor can change independently of thecharacter color." This is untrue. If theAtari is used in graphics mode 1 or 17, itsnormal text display is reduced to 24 rowsby 20 columns (similar to the VIC's 23

rows by 22 columns) and the backgroundcolor becomes separately adjustable toany of 16 colors. Mr Williams also incor-rectly stated that the Atari's normal textdisplay is "16 rows by 32 columns"; ac-tually it is 24 rows by 40 columns, whichmeans it can display 25% more text thanany of the other computers he surveyed.It also can be expanded to a full 32 Kbytes of memory by installing one of thenew 32 K-byte "RamCram" boards madeby Axlon (Sunnyvale, California).

On the whole, BYTE should make moreof an effort in the future to standardizecomparison tables. For example, the costof each system with a fully extendedBASIC in ROM (read-only memory) and

Data communications can open up a whole new world to you and your computer. A world ot the future. Now.A world full of information resources, time-sharing computer systems, and electronic "bulletin boards." All youneed for admission to this world is your CP/M- based computer, a modem, and the proper software. That's where wecome in. We have the proper software. CROSSTALK," our smart terminal & file transfer program for CP/M, allowsyou to call into thousands of dial-up computer systems around the world, and communicate with them. REMOTE,our CP/M remote console program, allows you to operate your CP/M system from a remote terminal, giving yourcomputer added flexibility and usefulness.

CROSSTALK

• Allows your computer and modem to communicate with other computers, including other CROSSTALK syslems,public-access "bulletin board" systems, main frame computers, subscription "Information utilities" such as THESOURCE,"" and much more.

• Simple, easy to use "plain English" command structure makes CROSSTALK easy to learn, yet provides a powerfultool for exchanging files, capturing data, and controlling modem parameters.

• Concurrent printer and video allows you to print data while viewing it on the CRT

• Fully error-checked file transfers using 16 bit CRC protocol. Protocol transfers allow exchanging files which arelarger than the systems memory.

• Built in "DIR" command.

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• Auto-dial, redial. and auto-answer (if supported by modem).

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16 K of programmable memory could begiven. The graphics capabilities should becompared in some way to show the trade-off between high-resolution and multi-color capabilities, such as the maximumresolution available if you want the abili-ty to display four colors simultaneouslywith individual color control over eachpixel. I would be interested to know howthe VIC with the Super Expander Car-tridge would compare with the othermachines reviewed according to thiscriterion. If the advertised 176 by 176pixels are individually assignable to any offour (or more) colors, then the graphicscapabilities of the VIC 20 would lie be-tween those of the Apple (280 by 192) andthe Atari (160 by 96), being approximate-ly equivalent to the Radio Shack ColorComputer (128 by 192).

Finally, Mr Williams mentioned thatthe VIC 20 uses the 6502A microprocessorinstead of the 6502. What's the difference?Also, is it possible to replace the 6502 witha 6502A7

George Fergus

1810 Hemlock PI #204

Schaumburg IL 60195

Gregg Williams Replies

Mr Fergus's two points about the Atariare correct—my apologies for the errors.His comments on the fairness of the com-parison chart point up the difficulty ofcomparing several microcomputers fully.Anyone buying a microcomputer shouldlearn everything he or she can about thedifferent brands (just as Mr Fergus did).Such an evaluation was beyond the scopeof the article 1 wrote, so I chose represen-tative configurations of the differentmicrocomputers.

The only difference between the 6502and the 6502A is the higher system-clockfrequency of 2 MHz for the 6502A. How-ever, a 6502A microprocessor would offerno improvement in an existing microcom-puter system without similarly upgradingthe access time of the memory and in-creasing the speed of the system clock(which may have harmful side effects).

APL Pals

I read Gregg Williams's article "ThreeVersions of APL" with great interest. (Seethe April 1981 BYTE, page 188.) His con-clusion that Vanguard APL/V80 is thefullest and fastest implementation is onethat we agreed with two years ago when

18 October 1981 © BYTE Publications tac

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Letters.

we made our own evaluation.

Since then, we have modified and en-hanced Vanguard APL extensively.MicroAPL's own APL 4.0 release is nowpacked with goodies for the APL enthu-siast. These include fast auxiliary proces-sors for text search, character-set transla-tion, laboratory instrument input/output;MicroTASK utility for project develop-ment, documentation, and screen handl-ing; MicroFILE software for four differenttypes of file access; MicroPLOT driversfor Tektronix, Hewlett-Packard, Qume,Diablo, and A-J plotters; MicroLINKworkspaces for online timesharing linksand CP/M file interchange; and Micro-SPAN, a complete computer-aided in-struction package for APL neophytes.

I hope BYTE will include us in its nextlanguage review. There are some excitingprojects in the pipeline for 16-bit APL sys-tems. APL is very popular in Europe, so inthe meantime, we hope European readerswill feel free to contact us if they're in-terested in further details.

Robert Bittlestone

MicroAPL Ltd

19 Catherine PI

Victoria, London, SW1E 6DX, England

Roots Fair and Square

Steve Abie's statement that any 10-digilcalculator that accurately yields(V2)2 = 2 "... is either doing "funnyarithmetic" or else is not telling youeverything it knows" aroused my curiosi-ty. (See "Letters," April 1981 BYTE, page16.) My rather ancient Texas InstrumentsSR-51A does, in fact, yield (V2)2 = 2. SoI wondered if it was performing "funny

arithmetic" or was hiding informationfrom me.

The SR-51A does calculate V2 to13-digit accuracy as does HP-41C, thendisplays the result rounded to 10 digits.The difference is that the SR-51A does notthen proceed to forget the additional threedigits. These are still retained in theregister and are used in any subsequentoperations.

The V2 operation produces a displayedresult of 1.414213562, but the internalmemory has 1.414213562373. Squaringcorrectly produces a rounded result of 2.The other functions also produce 13-digitaccuracy rounded to 10 digits for thedisplay.

In the words of Mr Abel, my SR-51A"is not telling me everything it knows."But, why should the accuracy of themachine be limited to the size of thedisplay7 Because it does not forget theextra three digits it calculated, the out-dated, middle-line SR-51A performs withgreater accuracy than the new, top-line,very expensive HP-41C.

In addition, my SR-51A, with a littletrickery, will tell me "everything itknows." Entering -Jl yields a display of1.414213562. First, I multiply this by 100,which produces 141.4213562; then I sub-tract 141, producing a display of0.4213562373. There are the three extradigits.

For it, the displayed result is3.141592654. Multiply this by 100, thensubtract 314, and the result 0.159265359 isdisplayed. This would be accurate for the14-digit value of tt = 3.1415926535897rounded to 13 digits. The trailing 0 is sup-pressed in the LED (light-emitting-diode)display to conserve the batteries.

It is also possible to enter 13 digits withan appropriate trick. To enter

1.414213562373, first enter 3.73 EE-10,then add 1.414213562. This will result inthe register containing 1.414213562373,and squaring this will produce therounded answer of 2.

Apparently, this accuracy cannot beachieved with "the world's fanciestcalculator."

James E KitchenDirector

Chapman CollegeResidence Education CenterGeneral DeliveryBeale AFB CA 95903

Talking DVMs

In Steve Ciarcia's "Build a Low-CostSpeech-Synthesizer Interface" (June 1981BYTE, page 46), he describes an encounterwith a disbelieving clerk "at a local elec-tronics store" after asking if they carried"any DVMs (digital volt ohmmeters) thattalked." Steve implies that today none ex-ist, but someday they will be very com-mon. Well, at least one does exist.

I recently came across a reference to a"talking DVM" in the March 1981 journalof Chemical Education (page 231). It'savailable from Sabtronics InternationalInc, 13426 Floyd Cr, Dallas TX 75243(product number DMM 2010A).

Charles J Spillner4054 Shona CtSan Jose CA 95124

The Franklin Institute Research Labora-tory also has a talking voltmeter avail-able. Contact the company at BenjaminFranklin Pky, Philadelphia PA 19103,(215) 448-1340. . . .

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Letters.

BDS C Update

Thank you, BYTE, for the "prinfi"technical note and the larger article onBDS C, by Chris Kern. (See "Printf for theC Function Library," May 1981 BYTEpage 430, and "The BDS C Compiler,"June 1981 BYTE, page 356.) Unfortunate-ly, the items have fallen victim to sometime-warp distortion, and several pointsregarding the package were out of date.

In the printf article, reference is made toa clumsy method of passing formal para-meters to C functions in which the para-meters are copied into absolute locationsin memory by the caller and accessedfrom there by the subordinate function.The parameter-passing mechanism ofBDS C has been totally revamped sincethose days. Currently, all parameters arepassed on the stack, and all local (auto-matic) variables also reside on the stack.Also, a printf that is functionally equiva-lent to Chris Kern's is now a standard partof the package.

The June review was completely accu-rate in all technical details, except for thestatement that "it's a shame the BDS com-piler doesn't go one step further and pro-vide redirected input and output. . . ."Actually, the current version of BDS Cdoes include a special-function library forperforming both directed I/O (input/out-put) and pipes in the standard UNIX-likemanner. This is a recent addition to thepackage, and it has the advantage of notwasting any memory if it isn't used, be-cause it's merely a simple set of libraryfunctions (written in C, of course).

BDS C users may be interested to knowthat the compiler has recently been rununder the MARC operating system (aUNIX-like system) and that the combinedpackage will be available soon fromVortex Technology. MARC furthers BDSoftware's tradition of translating the"best" of UNIX onto 8080- and Z80-basedsystems. BDS C finally has an operatingsystem it can appreciate, rather thanbattle.

Leor ZolmanBD Software33 Lothrop StBrighton MA 02135

22 October 1981 © BYTE Publications lnc

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Letters.

Points on Printers

In connection with the review "The Ep-son MX-80 and MX-70 Printers" (see theMay 1981 BYTE, page 22), the followingspecific comments may be of interest:

• The MX-80 offers four rather than threecharacter densities. The fourth is thedouble-width reduced character. It is pro-duced by an SO (shift-out) code when anSI (shift-in) code is in effect. The resultingdensity is 3.25 characters per cm (8Vi perinch).

• A fourth character style can be obtainedby transmitting codes for both boldfaceand emphasized. The result is a characterheavier in both horizontal and verticallines.

• Line spacings of less than y6 of an inchon the MX-80 are overridden whengraphic characters are present. In our ex-perience, even a single graphic characterin a line will cause the line feed to defaultto y6 of an inch. (This phenomenon is notcovered in the user's manual.)

• The annoying buzzer on the MX-80 canbe turned off by use of internal switch 1-6.

• The MX-70 (even though its charactermatrix is 5 by 7) produces a graphicmatrix of 480 by 8 pixels per line.

As for the Apple II interface, whichdoes not transmit the high bit and, hence,the graphic characters, the peculiarity liesin the Epson-designed interface, ratherthan the Apple's memory. Our companyproduces and distributes an interface forthe Apple II and the Epson printers thattransmits all bits and all characters. Wealso produce a firmware printer-supportcard for the Apple II. In conjunction withour interface, this card will (in addition tomany other functions) produce a low-re-solution graphic dump on the MX-80 us-ing the graphic characters and a high-reso-lution graphic dump on the MX-70, whichis printed as eight graphic lines on eachpass.

Aninon KatzPresidentInverted—A Inc401 Forrest Hill LnGrand Prairie TX 75051

I have just purchased the MX-70 ver-sion of Epson's printer, and I would like tomake two comments on the May 1981BYTE article.

First, the MX-70 can print with eight

points, not seven, which means that withspecial software it is possible to printlowercase descenders by utilizing thegraphics mode.

Second, the Epson interface card forthe Apple II computer has a link optionfor the most-significant bit that must bechanged to allow this bit to get to theprinter. The graphics mode requires a true16-bit (2-byte) argument to instruct theprinter as to how many bytes are to be in-terpreted as points on the print head.Also, a complete byte is required to definewhich print hammer is to strike. Before Idiscovered this, I had some weird effectsevery time I tried the graphics mode.

I think the graphics mode is the mostsignificant part of the MX-70 because itallows a large number of extra features tobe defined by the user:

• special-character sets

• proportional spaces between characters

• proportional spaces between words

• overstrike, and

• underlining

Bruce Piggott

725 Flower City Pk

Rochester NY 14615

Changing Names

Gary Stotts's Apple Name-Address pro-gram is so useful that I made a modifica-tion for my own purpose. (See the April1981 BYTE, page 32.) Although there is away to change the address and telephonenumber of a person listed on the file, thereis no way of changing a person's name.There may be reason to change the per-son's name: marriage, for example. I haveadded a few lines to the program to dojust that. (See listing 1).

Gino J Piazza

49 Browndale PI

Port Chester NY 10573

Listing 1

1172 PRINT : PRINT "OLD: ";N$(I)1175 PRINT : INPUT "NEW: ";N$(I)1177 IF LEN(N$(I)) < 1 THEN 1175 ■

Credit Due

We inadvertently omitted the credit linefor the photographer responsible for thephotographs in "A Look at NCC '81"(September 1981 BYTE). We apologize toRichard Faverty.

October 1981 © BYTE Publications tac

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Brooklyn NY 11201

IBM (International Business Machines Corporation)has at last introduced the keenly anticipated IBM Per-sonal Computer. Based on Intel Corporation's 8088microprocessor, the new machine is slated to appear instores this month, with various hardware options, at

Photo 1: The new IBM Personal Computer is based on the Intel8088 microprocessor and will be supported by software fromwell-known, independent sources. Shown here are the SystemUnit with two built-in 5-inch floppy-disk drives, the black-and-white video monitor, the adjustable keyboard, and an EpsonMX-80 printer bearing the IBM label, all of which sells for$4385.

prices ranging from $1565 to more than $5000. Colorgraphics are built in, and up to 256 K bytes of usermemory may be installed.

The hardware is impressive, but even more striking aretwo decisions made by IBM: to use outside software sup-pliers already established in the microcomputer industry,and to provide information and assistance to indepen-dent, small-scale software writers and manufacturers ofperipheral devices.

The list of software sources includes Microsoft, DigitalResearch, Personal Software, Peachtree Software,Softech Microsystems, and Information Unlimited Soft-ware. For hardware configurations including floppy-disk

See us at Comdex '81 in Las Vegas. Booth §774.

TVPe

«0" P°s^

« e

'Registered Trademarkol Digital Rii

TURBODOSisa prodSoltware 2000.

i

The BOS M System:The Universal Donor

The BOS M Card is the heart of the M System. It is designed tobe IEEE S-100 bus compatible for universal system use. Virtuallyall elements of a computer mainframe now reside on one S-100card — Z-80A CPU, 64k of 200ns RAM (no wait states),4k 250nsEPROM, Winchester Disk I/O port, two RS-232 serial ports, systemport, floating point processor, and parallel I/O. The same M Cardcan be used in single-user, multi-user, or even multi-processorsystems.

Second Generation Multi-Processor. With the BOS M Card,multi-processing is finally free of the Master/Slave and hand-shaking parameters so prevalent in first generation multiprocessors.Inter-system communications are FIFO buffered; the old "Master"is now a slave to the user, and the system functions without "S-100bus overrun" or system generated wait states.

The Universal Processor is now a reality! As a single-user system,the BOS M is unmatched in performance (up to ten times the speedof other microcomputers). Ab a multi-user system, this power canbe translated into a low cost multi-terminal capability. As a multi-processor, the system leaves the realm of "microcomputer" andcompetes in performance with a minicomputer! You can start with asingle-user computer and expand to a multi-user/multi-processorcomputer system when needed.

■HHHMMnHMHHMMHnHHHHMHHHHM|

The Universal Product. BOS has what you need — anythingfrom a single M Card to a complete turnkey computer system.Diskette, rigid disk, tape and telecommunications sub-systemsare all available. Compatible software includes CP/M*, MP/M*,CP/NET', BOS/TURBODOS, complete monitor, languages,application packages, and more!

Dealer and OEM Inquiries Welcome

^^^^^^ Business Operating Systems, Inc.

2835 East Platte AvenueColorado Springs, Colorado 80909n Colorado Call: (303) 634-1541

lairsi

Circle 49 on Inquiry card.

The BOS M System does what a Universal Donor must do — it provides high performance for allsystem types; single-user, multi-user, and multi-processor. M Systems start at less than $5,000.00 forsingle-user computer with dual 8" double density diskette drives.

drives, IBM will sell three different disk operating sys-tems: CP/M-86 from Digital Research, the UCSD p-Sys-tem from Softech Microsystems, and IBM Personal Com-puter DOS, developed by Microsoft in imitation ofCP/M. IBM isn't trying to force the world to choose be-tween the IBM DOS and other popular operating sys-tems. The published documentation of IBM PersonalComputer DOS will include the source-code listing of theBIOS (basic input/output system), and of the diagnosticprograms executed automatically when the computer isturned on.

The hardware uses an interconnection scheme differentfrom the industry-standard S-100 bus, but IBM doesn'twant to exclude anyone from developing plug-compati-ble printed-circuit boards for installation in any of the va-cant expansion slots inside the chassis. In fact, the com-pany plans to publish a hardware manual with drawingsand industry-standard specifications. IBM's attitudetoward support for independent hardware and softwareefforts was summarized by Don Estridge, Director ofEntry Systems Business for the IBM Personal Computer."IBM will provide information for the existing cottage in-dustry to design boards," Estridge said. "We're open toany software proposals."

General System Characteristics

The entry-level version of the IBM Personal Computerconsists of the System Unit, which contains the 8088microprocessor, a 40 K-byte built-in ROM (read-onlymemory) containing the extended version of MicrosoftBASIC, a built-in speaker that can be programmed toplay music, a power-on automatic self-test of systemcomponents, 16 K bytes of user memory in the form ofsemiconductor RAM (random-access read/write mem-ory), a combination video-monitor and printer adapter,and empty space for two 5-inch floppy-disk drives. Inthis minimal configuration, the system uses an audio-cas-sette recorder for mass storage and an ordinary televisionset as a video monitor.

Not including the cassette recorder and monitor, theminimal system will sell for $1565. With a single 5-inch,160 K-byte floppy-disk drive and 64 K bytes of userRAM, the price increases to $3005. An expanded businesssystem with powerful color graphics, two floppy-diskdrives, and an IBM-labeled Epson MX-80 dot-matrixprinter costs $4500. In addition to the 40 K-byte ROM,the system has a 16 K-byte RAM buffer for graphics op-erations. None of the user memory is required by the sys-tem software.

DATAFACE GRQ SERIES INTERFACE

TURNS YOUR ELECTRONIC TYPEWRITER INTO A PRINTER/TYPEWRITER

TheDatafaceGRQ-11 Inter-face expandsyourOlympiaESSeries electronic typewriter

into a letter press quality printer for your personal or busi-ness computer. And, you still have a fully featured electronictypewriter—two machines in one.

The GRQ Series Interface features:

1. Standard EIA RS-233-C Serial Interface and Parallel(Centronics compatible).

2. Standard asynchronous ASC11 code, 7 bit data; 1 startbit; accommodates 1 or 2 stop bits automatically; accom-modates odd, even or absence of parity bit.

3. Fifty thru 9600 Baud data rate options.

4. Two K buffer; supports X-on, X-off protocol as well asRTS signals.

28 October 1981 © BYTE Publications inc

5. Circuit board is installed in-side typewriter back panelalong side logic board. Theconnection between boards accomplished by 40 pinjumper cable using existing socket. No soldering required.Power is provided to the GRQ thru two pins of the 40 leadcable. Installation in 10 minutes.

End user, Dealer, Distributor and OEM inquiries are wel-come. For additional details, specifications and computercompatibility contact:

DflTFIFflCE inc.

2372 A WALSH AVE., SANTA CLARA, CA 95050(408) 727-6704

Circle 111 on inquiry card.

THE DAWN OFA NEW AGE

The 2nd Generation is here!

MEASUREMENT systems & controls proudlyintroduces its new and exciting "2nd Generation"family of S-100* compatible products. Each hasbeen specifically designed for use withmulti-user and networkoperating systems suchas MP/M, CP/NET, andOASIS. Every product isfully tested and burned-in, comes with a 1 yearguarantee, and offersyou features notcurrently available fromany other source.

Z80 PROCESSORBOARD — The mostpowerful CPU board available today. Outstandingfeatures include 4MHz operation, high-speed serialand parallel I/O utilizing DMA or programmedcontrol, eight vectored priority interrupts, and areal time clock.

MULTI-USER SERIAL I/O BOARD — For use inexpanded systems requiring up to eight additionalserial I/O ports. Features include: 16 maskable

* AH products meet the new IEEE standards.

Systems

a Division of MEASUREMENT systems &>. controls

incorporated

Circle 216 on inquiry card.

vectored priority interrupts, RS-232C interfaces

with full handshake, asynchronous or synchronous

operation with asynchronous baud rates to 19,200.

Available in four or eight channel versions.

DOUBLE DENSITY

FLOPPY DISK

CONTROLLER BOARD-

controls up to four 51/4-inch or 8-inch disk drivesusing IBM soft sectoredformats. It features 1Kof on-board buffering,DMA controlled datatransfers and the per-^ formance character-istics of the superiorNEC 765 chip.

64K BANK SELECTABLE MEMORY BOARD —

Features include I/O port addressing for bank

select with 256 switch selectable I/O ports for the

memory bank addressing. The memory is

configured as four totally independent 16K

software-selectable banks, with each bank

addressable on any 16K boundary.

"Attractive Dealer & OEM Prices"~ See your nearest computer dealer, or

contact us for the complete story onThe 2nd Generation.

1601 Orangewood Ave., Orange, CA 92668TWX/TELEX: 910 593 1350 SYSTEMGRP ORGE

Plug-in circuit cards of user RAM are available in threedenominations: 16 K bytes ($90), 32 K bytes ($325), and64 K bytes ($540). The user can increase the memorycapacity to 256 K bytes using the available IBM boardsand slots. (Outside companies could make a single mem-ory board containing 256 K bytes of RAM, or expansionboards that contain even more.) All user memory is 9-bit,with one bit devoted to parity check. An edge connectoron the back of the System Unit looks as if it is longing fora hard-disk drive, but IBM is mum on that possibility.

The 8088 processor communicates with memory andperipheral devices through an 8-bit data bus, but it con-ducts its internal affairs using the 16-bit instruction set ofIntel's 8086 microprocessor. In the IBM Personal Com-puter, the 8088 operates at 4.77 MHz, with a cycle timefor main storage of 410 nanoseconds; for access, the cycletime is 250 nanoseconds.

Together, the System Unit, keyboard, and a monitormake a very smart, full-feature terminal. A six-footcoiled cable connects the separate keyboard to the Sys-tem Unit. You can adjust the keyboard's tilt toward youwhen it rests on a desktop, or you can hold it in your lap.The system supports both uppercase and lowercase char-acters, and all 83 keys have automatic repeat. Ten keyson the right side are for a numeric keypad and cursorcontrols, and ten special-function keys can be used forediting. The keyboard provides access to 256 characters,including all the ASCII (American Standard Code for In-formation Interchange) characters and many other char-acters useful for producing virtually any sort of graphicsdisplay.

IBM sells an HVz-inch green-phosphor video monitorfor $345. The monitor displays 25 lines of 80 characterseach. You can adjust brightness and contrast or use soft-

H

11

=,

*=•■

t^^r^yr=;J; 1

AAMAJOR BREAKTHROUGH!

C3 □

20 MByt

The SYSTEM 2800, designed forbusiness, industrial and educationalapplications, Is now available with a20 MByte Winchester Hard Disk and a20 MByte Tape Drive for disk backup.Created to be innovative and com-petitive, the SYSTEM 2800 utilizes ourexisting line of field-proven anddependable "2nd Generation" S-100Memory, Z80 Processors, Disk Con-trollers and Serial I/O boards.

As a family of expandable micro-computers Intended for single andmulti-user applications based onCP/M\ MP/M* and OASIS* \ theSYSTEM 2800 contains many big sys-tem features. Outstanding character-istics such as FAST operation make ita clear market leader. In fact, theSYSTEM 2800 Is one of the fastestZ80-ba8ed systems recently bench-marked by Interface Age magazine.

"CP/M and MPIM ace Registered

■ademark of Phase On

Other featues include the capabili-ty to BOOT from any drive Includingthe hard disk, and extensive errorrecovery. The error recovery promptsthe user with detailed error messagesand prevents system lock up, all toocommon to many other systems.

Designed for easy service, theSYSTEM 2800 comes with two 8-inchdrives: a choice of single or doublesided, double density floppies with upto 2.52 MBytes of formatted storage;10 or 20 MByte Winchester hard disk;and 20 MByte tape drive for diskbackup.

These enhanced features result in alighly reliable, quality built, state-of-

th Tape Backup

the-art microcomputer that gives youthe cost/performance edge you needto be a leader in your field.

Dealers, OEM's and System In-tegrators share many common needs.Not the least of these is dependableproducts. That's why we back ourSYSTEM 2800 with our establishedreputation for high quality, superiorsupport, prompt and courteous ser-vice, an inclusive one-year warrantyand comprehensive dealer supportprogram.

Take the next logical step. See yournearest computer dealer, or contacius for the complete story on our S-100family of board products and en-

hanced systems.

Systems

.'•ot MEASUREi

oraied

1601 Orangewood AvenueOrange, Calif. 92668 (714) 633-4460

92 1350 SYSTEMGRP

Group I

"died

>od Avenue

; (714)633-4460

) SYSTEMGRP ORQE

ware to activate underlining, high-intensity blinkingcharacters, and reverse video.

With a color monitor, the IBM Personal Computer willsupport 16 foreground and eight background colors. Inthe medium-resolution graphics mode, screen resolutionis 320 pixels (picture elements) across by 200 down. In thehigh-resolution graphics mode, resolution is 640 by 200pixels. Text and graphics can be mixed, allowing you tolabel items in a graphics display.

One Centronics-compatible parallel printer port andone RS-232C serial I/O (input/output) port are standard.An asynchronous communications adapter ($150) en-ables you to connect a modem to the serial port.

IBM is even offering a Game Control Adapter ($55)that permits connection of user-supplied joysticks andpaddles to the IBM Personal Computer.

Sales and Service

IBM's sales and service strategies show the computergiant's determination to develop quickly into a majorforce in the microcomputer market. Beginning this

month, the company is marketing the Personal Computernationwide in four ways:

• through Computerland retail stores

• through Sears, Roebuck and Company's new business-machine stores (IBM will train the Sears sales personnel)

• through a special sales unit in the IBM Data ProcessingDivision (for high-volume sales)

• through IBM Product Centers, which will make provi-sions for installment purchases

Only four Product Centers exist now, but IBM hasselected many more cities around the country as sites forfuture centers. "In the course of the next two years," saidC B Rogers, Jr, IBM vice president and group executive ofthe General Business Group, "we expect to be fairly wellrepresented."

IBM will offer a 5 percent discount on sales of 20 to 49units, 10 percent on sales of 49 to 150 units, and 15 per-cent on sales of 151 units or more. Educational institu-tions will also receive discounts.

_At a Glance.

Product Name

The IBM Personal Computer

Manufacturer

International Business Machines Corporation

Information Systems Division

Entry Systems Business

POB 1328

Boca Raton FL 33432

When Available

October 1981

Where Available

Sears, Roebuck and Company's business-machines stores

Computerland stores

IBM Product Centers

IBM Data Processing Division (volume sales)

Components

System Unit

Size: width 20 inches, depth 16 inches, height 5.5 inches;

weight (without disk drives) 21 pounds, (with two diskdrives) 28 pounds

Electrical needs: 120 VAC

Processor: Intel 8088

Cycle Time: main storage, 410 nanoseconds; access,250 nanoseconds

Memory: 40 K bytes of built-in ROM (read-only memory),16 K bytes of user RAM (random-access read/write memory); expandable to 256 K bytes

Standard: keyboard for data and text entry; audio-cassetterecorder connector; five expansion slots formemory, display, printer, communications, andgame adapters; built-in speaker for music program-ming; power-on automatic self-test of system com-ponents; BASIC-language interpreter; 16 K bytesof user RAM (all user RAM is 9-bit paritymemory)

Keyboard: 83 keys for data and text entry, 10 keys for

numeric entry and cursor control, 10 special func-tion keys, and ASCII characters and specialgraphics characters (total 256 characters);automatic repeat on all keys; adjustable typingangle; detachable six-foot coil cable

Disk drives: up to two 5-inch floppy-disk drives, 160 K byteseach

Operating Systems

IBM Personal Computer DOS (Microsoft)

CP/M-86 (Digital Research)

UCSD p-System (Softech Microsystems)

Software Available for IBM Personal Computer DOS

BASIC interpreter (Microsoft) standard; extended BASIC inter-preter (Microsoft) $40; Pascal compiler (Microsoft) $300; VisiCalc(Personal Software) $200; Easywriter (Information Unlimited Soft-ware) $175; General Ledger, Accounts Receivable, AccountsPayable (Peachtree Software) $595 each; asynchronous com-munications support $40; Adventure (Microsoft) $30

Hardware Prices

System Unit, 16 K-byte RAM, keyboard $1265System Unit, 48 K-byte RAM, keyboard

single floppy-disk drive, disk-drive adapter 2235

Monochrome video display 345Combination monochrome-display adapter

and printer adapter 335

Color-graphics-monitor adapter 300

16 K-byte memory-expansion kit 90

32 K-byte memory-expansion kit 325

64 K-byte memory-expansion kit 540

Disk-drive adapter 220

Disk drive (5-inch floppy disks) 570

Asynchronous communications adapter 150

Game-control adapter 55

Keyboard 270

32 October 1981 © BYTE Publications Ire

The guy on the leftJ^esn't stand a chance.

uy on the left has two file folders, a news maga- transmission couplers mean you need never work without

oonHu/ir^h tho nanahilitioe ni tho OQRHRMF 1 Thot'c nnnri honanco

• I

The guy on the left has two file folders, a news magazine, and a sandwich

The guy on the right has the OSBORNE 1 ®, a fullyfunctional computer system in a portable package the sizeof a briefcase. Also in the case are the equivalent of over1600 typed pages, stored on floppy diskettes.

The owner of the OSBORNE 1 is going to get morework done—and better work done—in less time, and withless effort.

Unfold it, plug it in, and go to worklike you've never worked before. . . .

Go to work with WORDSTAR® word processing, soyour correspondence, reports, and memos take less timeto produce, and say more of what you wanted to say. Andwith MAILMERGE®—the mailing system that turns outpersonalized mass mailings in the time you'd spend on arough draft.

Go to work with SUPERCALC®, the electronicspreadsheet package that handles complex projections,financial planning, statistics, and "what if" questions in-stantly. For the more technically minded, SUPERCALC willprocess scientific data and calculate results.

Go to work with powerful BASIC language tools—the CBASIC-2® business BASIC, or the Microsoft BASIC®interpreter.

That's standard equipment.

Options include about a thousand different softwarepackages from a host of vendors designed to run on theCP/M® computer system.Go to work at the office, at home, or in the field.

Or anywhere. Optional battery packs and telephone

Circle 284 on inquiry card.

transmission couplers mean you need never work withoutthe capabilities of the OSBORNE 1. That's good, becauseyou won't want to work again without it.All for $1795. It's inevitable.

The OSBORNE 1 is the productivity machine that'schanging the way people work. Put simply, the machinedelivers a significant productivity edge—day in and dayout—to virtually anyone who deals with words or num-bers. Or both.

Since the entire system is only $1795, it won't be toolong before the guy on the left has an OSBORNE 1 of hisown. The same probably goes for the person readingthis ad. In fact, we think it's inevitable.

The OSBORNE 1 includes a Z80A«'CPU,64Kbytes of RAM memory, two 100 kilobytefloppy disk drives, a business keyboard,built-in monitor, IEEE 488 and RS232 inter-faces for printers and other things thatget connected to computers, plusCP/M, CBASIC-2, Microsoft BASIC,WORDSTAR, and SUPERCALC. Thesystem is available from computer retailers nationally.

$1795. It'sinevitable.

COMPUTER CORPORATION

26500 Corporate Avenue Hayward, California 94545Phone (415) 887-8080 TWX (910) 383-2021

BYTE October 1981

33

IBM's service plans should meet or exceed those offeredby other microcomputer manufacturers. For a start, IBMoffers a 90-day warranty. Owners can extend warrantiesto a full year for between 7 and 9 percent of the purchaseprice of various system components, or buy annual ser-vice contracts for 10 to 15 percent of the purchase price ofcomponents. For example, an extended warranty for theSystem Unit costs $88; a maintenance contract for theSystem Unit costs $112. For the System Unit, disk drive,and disk-drive adapter, an extended warranty costs $154,and a maintenance contract costs $196.

Service will be available at Sears, Computerland, andfrom the IBM Product Centers, regardless of where youbought the computer. Service contracts with the IBMProduct Centers call for exchange of major system com-ponents. IBM will send a replacement keyboard, printer,or System Unit by courier within 48 hours of the owner'scall.

Three Ways to Generate Software

Recognizing the advantage that an existing broad soft-ware base gives to CP/M-compatibie, Radio Shack, andApple computers, IBM plans to meet the problem head-on with a three-part strategy.

First, when the Personal Computer reaches stores thismonth, it will be accompanied by a software offer includ-ing some application programs ready to run with IBMDOS. Here's a quick look at what IBM is offering:

• IBM Personal Computer DOS. This CP/M look-alikefrom Microsoft offers the familiar "A > " prompt charac-ter along with features for copying files and disks, com-paring files and disks, initializing disks, displaying adirectory, renaming files, and other housekeeping chores.Although it has a debugger and a line editor, IBM DOSdoes not yet have an assembler. It seems safe to speculatethat Microsoft is hard at work on that.

• a cassette-level enhanced Microsoft BASIC interpreterthat supports input/output instructions, use of the key-board, display, light pen, and printer, and many editingand mathematical functions.

• a disk-level Microsoft BASIC that provides extensionsincluding more powerful graphics, date and time-of-dayfunctions, and communication capabilities; the enhancedgraphics include such features as point, circle, andget/put display, and increased light-pen support for de-sign work ($40)

• a Pascal compiler, also from Microsoft ($300)

• VisiCalc, the electronic-worksheet program from Per-sonal Software

• Easywriter, the word-processing program from Infor-mation Unlimited Software ($175)

• an asynchronous communications program ($40) (Thisis written in BASIC and is menu-driven; the menu in-cludes an option for the Dow Jones Information Services,another for The Source, and another for teletypewriter-like communications. IBM soon will also offer a fullsubset of Model 3270 emulation capabilities so that the

Personal Computer can appear to larger IBM systems asan IBM 3270 terminal.)

• general-ledger, accounts-payable, and accounts-receiv-able packages, from Peachtree Software, but with colorand other enhancements for ease of use ($595 each)

• Adventure, the fantasy-simulation game, from Micro-soft ($30)

The second part of IBM's software-developmentstrategy is to offer Digital Research's CP/M-86 operatingsystem and Softech Microsystem's UCSD p-System(which includes UCSD Pascal). Purchasers of these oper-ating systems will have access to many third-party pro-grams as they become available. IBM says it expects theavailability of these operating systems to provide the op-portunity for many current applications to be transferredto the IBM Personal Computer with minimal modifica-tions. This approach will enable owners of the IBM Per-sonal Computer to use a tremendous amount of softwareoriginally written for other common machines. Users canhave everything that IBM offers without giving up soft-ware for the other two operating systems.

The third part of the IBM software strategy is toestablish its own Personal Computer Software PublishingDepartment. The new department will solicit softwarefrom outside authors, both professional and amateur.IBM will send software-submission information packetsto anyone who writes to IBM Personal Computer Soft-ware Submissions, Dept 765, Armonk NY 10504. IBMwill also encourage its employees to write software forthe personal computer (on the employees' own time).Authors will receive quarterly royalties based on actualsales.

A Shaking Out?

For those of us who dislike giants, the IBM PersonalComputer comes as a shock. I expected that the giantwould stumble by overestimating or underestimating thecapabilities the public wants and stubbornly insisting onincompatibility with the rest of the microcomputerworld.

But IBM didn't stumble at all; instead, the giantjumped leagues in front of the competition. Although theIBM Personal Computer has not (as of this writing)reached store shelves, it already seems to hold a firmposition in the field. Its prices seem to compare favorablywith available 16-bit S-100 systems. Furthermore, thecost of an IBM Personal Computer configured for wordprocessing is not much more than that of an Apple IIPlus, an Intertec Superbrain, or most other 8-bitmachines fully equipped for word processing. A superiormachine from the start, the IBM Personal Computershould grow in capability as outside vendors begin pro-ducing peripheral devices and add-on hardware forspecial applications.

In fact, the only disappointment about the IBM Per-sonal Computer is its dull name. One rumor claimed thatIBM referred to this computer internally as the Acorn. Tome, it looks more like a Mighty Oak.B

34

October 1981 © BYTE Publications Inc

STRUCTURED SYSTEMSFINANCIAL SOFTWARE.

LESS IS CHEATINGYOUR OWN

Penny wise and software foolish. One of fhebest ways to cheat your business is to waste a wholelot of time on solutions that don't work, or that can'tgrow with your business. And frankly, we get phonecalls every day from computer users who've tried toget by on "bargain" software, and found that "bar-gain" software is the most expensive kind a businesscan own.

Here's a fact: if you have a real need for acomputer in any of these areas:

General Ledger

Accounts Receivable

Accounts Payable

Order Entry

Inventory Control

Payroll,any business software less than Structured SystemsFinancial Software is cheating your business. You'llcheat 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 controlsand reliable error prevention features. Out of thetraining you invest in a system you outgrow whenyou need to add more disk storage, more customers,more data. You'll be cheating yourself out of a soft-ware bargain in the truest sense of the word—thegreatest value for your dollar.

CP/M® microcomputer systems can do thejob of minicomputers. StructuredSystems software makes that po-tential a reality. Right now,hundreds of businessesare profiting from thefinancial controls andoperating efficiency of fSSG financial softwareSo can yours.

r

Take it easy on yourself.But sentence your computerto hard labor.

Please send moreinformation on your

O General Ledger

D Accounts Payable

Name

soul

„*>&&

sC,<ou?

□ Accounts Receivable □ Order Entry

□ Payroll □ Inventory Control

L

Company

Address

City State ZipTelephone (

CP/M is a registered trademark ol Digital Research.

Structured Systems Group

5204 Claremnnt. Oakland. /California 9461R f415K5471567 INCORPORATED!

5204 Claremont, Oakland, •'California94618 (415)5471567

Circle 351 on inquiry card.

BYTE October 1981 35

Ciarcia's Circuit Cellar

Build an IntelligentEPROM Programmer

Steve Ciarcia

POB 582

Glastonbury CT 06033

Longtime followers of the activitiesin Ciarcia's Circuit Cellar mayremember an incident I wrote about afew years ago. My friend Jerry need-ed to program an EPROM (erasableprogrammable read-only memory)device in a hurry for a demonstration

Copyright ©1981 by Steven A Ciarcia. Allrights reserved.

at his computer club. The EPROM-programming arrangement we de-vised gave me the idea for the article"Program Your Next EROM inBASIC" (March 1978 BYTE, page84), in which I presented a design foran inexpensive programming circuitand told how to drive it with softwarewritten in a high-level language.

EPROM technology has advancedconsiderably since then. In 1978, the

Photo 1: Complete intelligent EPROM-programming system, consisting of theZ8-BASIC Microcomputer, the EPROM-programming interface of figure 4b, anda video-display terminal.

type-2708 EPROM chip, which re-quires a three-voltage power supply,was just becoming established,replacing the hard-to-programtype-1702 EPROM device. Not onlywas the 2708 easier to program, italso held more data: 1 K (1024) 8-bitwords, compared to 256 8-bit wordsstored by the 1702 EPROM.

The 2708 EPROM has been re-placed in most new designs by thesingle-voltage type-2758 EPROM,and a number of higher-capacitydevices that require only a single-voltage power supply have beendeveloped and made available byseveral manufacturers. These are thetype-2716 (2 K 8-bit words, or 16 Kbits), type-2732 (4 K 8-bit words),and type-2764 (8 K 8-bit words)EPROMs. The 2716 has becomeespecially popular, partly because its2 K bytes are sufficient memoryspace for storing most bootstraploaders, command monitors, andsimple utility programs; and partlybecause the 2716 is usually pricedunder $10.

The 2758, 2716, and 2732 EPROMsare members of the same family ofcomponents, sharing a commonpinout specification. With only minormodifications to the wiring, adesigner can allow different-capacitymemory devices to be plugged intothe same socket on a circuit board.This versatility also means the samebasic circuit can serve in several ap-plications.

My previous article on EPROMssuggested using an interpreted BASIC

36

October 1981 © BYTE Publications Inc

program to drive the EPROM-programming circuit. This idea didwork, but it took a long time to pro-gram a 2708 EPROM. If you wantedto program more than a few 2708s,you would have been wise to pack abox lunch for the occasion. TheBASIC program demonstrated thealgorithm for programming anEPROM, but a machine-languagedriver program was needed for prac-tical large-scale EPROM program-ming.

The slow speed for programming,or "burning," 2708s this way resultsfrom the need to iterate the writepulse 100 times for each byte loca-tion. Each byte in the 2708 must bewritten for at least 100 ms(milliseconds) to assure stability ofthe stored data. However, this100 ms duration must consist of 100separate, pulsed write sequences,each lasting only 1 ms. All 1024 bytelocations must be addressed in se-quence while a +25 V programmingpulse is applied for 1 ms for each ad-dress. The cycle is then repeated 100times.

The 2716, on the other hand, re-quires only one loop through all theaddresses, instead of 100 loops. Whileeach location is being addressed, a50 ms programming pulse is applied,usually timed by a one-shot(monostable multivibrator). The50 ms, single-loop programmingconditions fall well within the speedcapabilities of BASIC, and nomachine-language driver routine needbe written for serious use.

Using a program essentially thesame as the one presented in theoriginal article (running under an 8 KBASIC interpreter on a Z80microprocessor with a 2.5 MHzclock rate), a 2716 can be completelyburned in 154 seconds, requiring75 ms per location. The minimumtime required with a machine-language driver is 103 seconds, or50 ms per location. The difference ishardly noticeable.

Because EPROMs are so widelyused, I thought it was about time towrite another article on them, featur-ing the 2716. First, I'll discuss whyEPROMs are used and how theywork, and then I'll describe the design

of my new EPROM-programmingcircuit.

What is different about this newcircuit? I decided to "unbundle" thesystem and design the EPROM pro-grammer as a stand-alone, intelligentunit. By incorporating the Z8-BASICMicrocomputer (my July-August Cir-cuit Cellar project), we can easily puttogether a stand-alone 2716 program-mer with capabilities that rival thoseof units costing ten times as much.(See "Build a Z8-Based Control Com-puter with BASIC, Part 1," July 1981BYTE, page 38, and "Part 2," August1981 BYTE, page 50.)

Whys and Wherefores of EPROM

A personal computer, even in itsminimum configuration, always con-tains some user-programmablememory or RAM (random-accessread/write memory), usually in theform of semiconductor memory in-tegrated circuits. This memory cancontain both programs and data. Anymachine-word-level storage elementwithin the memory can be individual-

ly read or modified (written) asneeded.

Any of several kinds of electroniccomponents can function as bit-storage elements in this kind ofmemory. TTL (transistor-transistorlogic) type-7474 flip-flops, bistablerelays, or tiny ferrite toroids(memory cores) are suitable, but allcost too much, are hard to use, andhave other disadvantages.

In personal-computer and othermicroprocessor-based applications,the most cost-effective memory ismade from MOS (metal-oxidesemiconductor) integrated circuits.Unfortunately, data stored in thesesemiconductor RAMs is volatile.When the power is turned off, thedata is lost. Many ways of dealingwith this problem have been devised,with essential programs and datausually stored in some nonvolatilemedium.

In most computer systems, somedata or programs are stored in non-volatile ROM (read-only memory). Asemiconductor ROM can be random-

Photo 2: Closeup of the EPROM programmer. On the right is the Z8-BASICMicrocomputer circuit board with the program-controller software resident in theonboard EPROM. On the left is the prototype type-2716 EPROM programminginterface. It includes a control panel, an operator display (LEDs), a zero-insertion-force EPROM socket, and a 4 K-byte buffer memory.

October 1981 © BYTE Publications Inc 37

ly accessed for reading in the samemanner as the volatile memory, butthe data in the ROM is permanent. Ina mask-programmed ROM, the datathat can be read is determined duringthe manufacturing process.Whenever power is supplied to theROM, this permanent data (or pro-gram) is available. In small computersystems, ROM is chiefly used to con-tain operating systems and/or BASICinterpreters—programs that don'tneed to be changed.

Another type of ROM is thePROM (programmable read-onlymemory). A PROM component isdelivered from the factory containingno data. The user decides what datahe wants it to contain, and per-manently programs it with a specialprogramming device. Once initiallyprogrammed, PROMs exhibit thecharacteristics of mask-programmedROMs. You might label such PROMsas "write-once" memories.

The ultraviolet-light-erasableEPROM is a compromise between the"write-once" kind of PROM and thevolatile memory. You can think ofthe EPROM as a "read-mostly"memory, used in read-only modemost of the time but occasionally

SELECT GATE(VQ)

^--^PinsMode^^^

CE/PGM(18)

OE(20)

(21)

Vcc

(24)

Outputs(9-11,13-17)

Read

V,L

Va

+ 5

+ 5

D„„,

Standby

Vw

Don't care

+ 5

+ 5

Highimpedance

Program

Pulsed Va

to Vm

Vm

+ 25

+ 5

0*

ProgramVerify

Va

Va

+ 25

+ 5

D„„,

ProgramInhibit

Vtt

v,„

+ 25

+ 5

Highimpedance

Table 1: Voltages present at specified pins of the 2716 during the five modes ofoperation. V,L must be in the range —0.1 V to + 0.8 V; Vw must be in the range+2.0 V to Vcc + 2.

erased and reprogrammed asnecessary. The EPROM is erased byexposing the silicon chip toultraviolet light at a wavelength of2537 angstroms. Conveniently, mostEPROM chips are packaged in anenclosure with a transparent quartzwindow. (I once wrote about a dif-ferent kind of "read-mostly"memory, the EAROM: electricallyalterable read-only memory. AnEAROM is erased by purely electricalmeans, without resorting toultraviolet light. See "Add Non-

SILICONDIOXIDE

SILICON

P-TYPE IMPLANT

P-TYPE SILICON SUBSTRATE

Figure la: Physical structure of one bit-storage cell in a 2716 EPROM. The cell consistsof a FAMOS (floating-gate avalanche-injection metal-oxide semiconductor) field-effecttransistor manufactured in a stacked-gate configuration. During programming, avoltage placed on the select gate creates an electric field within the structure. The fieldraises the energy levels of electrons passing through the channel from drain to sourceenough that some of the electrons are able to tunnel through the silicon-dioxide in-sulator and accumulate on the floating gate.

volatile Memory to Your Computer,"December 1979 BYTE, page 36.)

How the EPROM Works

EPROMs made by Intel Corpora-tion and several other manufacturersstore data bits in cells formed fromstored-charge FAMOS (floating-gateavalanche-injection metal-oxide-semiconductor) transistors. Suchtransistors are similar to positive-channel silicon-gate field-effect tran-sistors, but with two gates, as shownin figure la. The lower, or "floating,"gate is completely surrounded by aninsulator layer of silicon dioxide, andthe upper "control" or "select" gate isconnected to external circuitry.

The amount of electric charge

A7[

1 24

]VCC

A6[

2

23

]A8

A5[

3

22

] A9

A4 [

4

21

3vPP

A3 [

5

20

]0l

A2[

e

19

] A10

M[

18

]cE/PGM

A0[

8

17

]07

00 [

9

16

] D6

Dl[

10

15

] D5

D2[

11

14

] °*

gnd[

12

13

]D3

Figure lb: Pinout specification of thetype-2716 EPROM (erasable program-mable read-only memory) integrated-circuit package.

38

October 1981 © BYTE Publications Inc

stored on the floating gate determineswhether the bit cell contains a 1 or a0. Charged cells are read as 0s; un-charged cells are read as Is. When theEPROM chip comes from the factory,all bit locations are cleared of chargeand are read as logic Is; each bytecontains hexadecimal FF.

When a given bit cell is to beburned from a 1 to a 0, a current ispassed through the transistor's chan-nel from the source to the gate. (Theelectrons, of course, move the op-posite way.) At the same time, arelatively high-voltage potential isplaced on the transistor's upper selectgate, creating a strong electric fieldwithin the layers of semiconductormaterial. (This is the function of the+ 25 V charging potential applied tothe 2716.) In the presence of thisstrong electric field, some of the elec-trons passing through the source-drain channel gain enough energy totunnel through the insulating layerthat normally isolates the floatinggate. As the tunneling electrons ac-cumulate on the floating gate, thegate takes on a negative charge,which makes the cell contain a 0.

When data is to be erased from thechip, it is exposed to ultraviolet light,which contains photons of relativelyhigh energy. The incident photons ex-cite the electrons on the floating gateto sufficiently high energy states thatthey can tunnel back through the in-

sulating layer, removing the chargefrom the gate and returning the cell tothe 1 state.

Programming the 2716

The 2716 EPROM contains 16,384(16 K) bit-storage cells configured as2048 individually addressable bytes.This organization is often called "2 Kby 8." The completely static opera-tion of the device requires no clocksignals.

The pinout specification of the2716 is shown in figure lb, and ablock diagram of its internal structureis shown in figure lc.

The 2716 has five differentoperating modes, for which the input-voltage requirements are shown intable 1. The read, standby, and pro-gram modes are the ones I'll discuss indetail, since the program-inhibit andprogram-verify modes are importantprimarily in high-volume applica-tions.

In the read mode, two control in-puts are used to select the chip afterthe processor has selected thememory address. The OE (outputenable) line is provided mainly as ameans of jointly selecting a bank ofseveral 2716s, perhaps by a connec-tion to the memory-read line on thesystem bus. The CE/PGM (chipenable/program) input is decodedand used as the primary device-selecting line.

DATA OUTPUTS00-D7

OECE/PGM

A0-A10

ADDRESS (

INPUTS

CHIP-SELECT,POWER-DOWN, ANDPROG. LOGIC

OUTPUT BUFFERS

Y DECODER

Y-GATING

*■

X DECODER

16,384-BITCELL MATRIX

Figure lc: Block diagram of the internal structure of the type-2716 EPROM.

After the logic level present on theCE/PGM pin has been brought low,the OE input should also be broughtlow. Then 120 ns (nanoseconds)elapse before the addressed data isavailable on the data-output pins.This is sufficiently fast to be compati-ble with other types of memorydevices in most systems, allowingdirect connection of the 2716 to thesystem bus for reading data, asshown in figure 2a on page 40.

The 2716 can be placed in the staticstandby mode to reduce the powerconsumption without increasing theaccess time once it is addressed. Witha TTL high level applied toCE/PGM, the output lines assume ahigh-impedance condition. It doesn'tmatter what voltage is present on~OET

In the program mode, particular bitcells are induced to contain 0 values.Both Is and 0s are present in the dataword presented on the data lines ofthe 2716, but only the presence of a 0causes action to take place.

When the VPP power-supply inputis placed at a potential of +25 V andthe OE input is at a high level (V,H),the TTL-level data to be programmedfor a specific address is set up on the2716's data lines, and the address isset up on the address lines A0 throughA10. After a setup time of at least2 /as (microseconds), a high TTL-level programming pulse 50 ms longis applied to the CE/PGM input. Ad-dresses to be programmed may bespecified in any order.

The 50 ms programming pulsemust be applied once for each loca-tion to be programmed. Under no cir-cumstances should a constant highlevel be applied to the CE/PGM in-put in the program mode. Repeated50 ms pulses to the same location areacceptable, but any pulse widthgreater than 55 ms might destroy thechip. (The minimum pulse width is45 ms.) Using a nonretriggerableone-shot (monostable multivibrator)to generate the pulse is one simpleprotective measure.

A Simple EPROM Programmer

As we have previously seen, in theread mode the 2716 may be connected

October 1981 © BYTE Publications lnc 39

directly to the system's address anddata buses. It's not so easy, however,in the program mode.

Because of the setup-time intervalthat must elapse after the addressdata are presented, the programmingpulse must come at an instant thatdoesn't fit too well within the syn-chronous operating constraints of thetypical computer system bus. Thislimitation is most easily overcome byusing three parallel output ports tocommunicate with the EPROM. Theaddress and the data can be held con-stant while the programming pulse isapplied. Figure 2b shows a blockdiagram of this scheme, and figure 3shows the schematic diagram of an

WRITE/PROGRAM

actual circuit that uses this principle,which can be used with almost anypersonal computer.

The simple EPROM-programmingcircuit uses two integrated circuitsbesides the EPROM: the Intel 8255PPI (Programmable Peripheral Inter-face) and a type-74121 one-shot. The40-pin 8255 contains three separateI/O (input/output) ports. Twenty-four I/O lines can be programmed forvarious input, output, and controlfunctions. (For more information onthe 8255 PPI, see "Interfacing theS-100 Bus With the Intel 8255," byDavid L Condra, October 1979BYTE, page 124, or the Intel Compo-nent Data Catalog.)

8-BIT PARALLELOUTPUT LATCH

ADDRESS

2716A0-A10 OE

CE/PGM

+ 25V21 £

+ 5V20 £

18

-<Z2 PULSE

-1

50ms

+ 5V

0V

Figure 2a: For read-mode operation, the 2716 EPROM is fast enough that it can bedirectly connected to the address and data buses of most microcomputer systems. TheOE (output enable) line is usually used as a means of jointly selecting a bank of 2716s,while the CE/PGM (chip enable/program) line is used to select the particular in-tegrated circuit that is to be addressed.

In this application, I set up the 8255to operate in two different configura-tions. When programming, ports Band C contain the address, and portA contains the data. All three portsare set up for output. When verifyingthe contents (in read mode) after pro-gramming, ports B and C again con-tain the address, but port A is set forinput to read output data from the2716.

The 8255 is relatively simple to use.Its four internal registers for portsand control are accessed just like anyother I/O device. Using a combina-tion of chip-select and address-decoding logic, particular combina-tions of logic levels on the A0 and Allines designate the specific register be-ing addressed, as shown in table 2.The data word written into the mode-control register configures the par-ticular functions of the 24 I/O bits.

Setting all three ports for output isaccomplished by writing hexadecimal80 into the mode-control register. Theother combination, B and C set foroutput with A set for input, is ar-ranged by loading hexadecimal 90 in-to the mode-control register. Thesetwo control codes are the only onesrequired.

The EPROM interface in figure 3requires the operator to select theread or program mode by the posi-tion of a toggle switch. In the readmode, the Vpp power input will be at+ 5 V, and CE/PGM and OE willbe at logic 0. In the program mode,with the switch closed, Vpp will be at+ 25 V, OE will be at logic 1, andthe one-shot will be strobed for eachsuccessive location. The driver pro-gram which coordinates this effort

READ

ADDRESS BUS

D

DATA BUS

n

D0-D7

Vpp

2716

A0-A10 OE

+ 5V21 ^

^7

~~d?

Figure 2b: In the write-program mode, the need for an asynchronous programmingpulse necessitates the use of external data latches, driven by the output ports of the con-trolling computer system.

Register

Address BitsA0 A1

Port A

0 0

Port B

0 1

Port C

1 0

Mode-ControlRegister

1 1

Table 2: Addressing of port andmode-control registers in the Intel 8255Programmable Peripheral Interface.

40 October 1981 © BYTE Publications Inc

will be essentially the same as that forthe more sophisticated EPROM pro-grammer yet to be described.

An Intelligent Programmer

The 2-chip EPROM programmerpreviously described is an interfacedesigned to be attached to a program-development-type computer system.It can do just as much as the one I amabout to discuss. However, what Ihave in mind is better than a mereEPROM-programming interface: anintelligent EPROM programmer, astand-alone device that functionsonly as a programmer.

In my opinion, such a programmershould be able to perform the follow-ing tasks: accept raw input data byvarious means and store this data in abuffer memory, read a previouslyprogrammed EPROM and store thecontents in the buffer, write the con-

tents of the buffer into anotherEPROM, and compare the contentsof the same or a different EPROMchip to the buffer. In essence, theseare standard load, program, andverify functions consistent with anyreasonably useful 2716 programmer.

Photo 1 on page 36 shows the pro-totype of such a device. The in-telligence for this programmer is sup-plied by a Z8-BASIC Microcomputer,a single-board computer specificallyconfigured for use as a controller indedicated applications. Using thisZ8-based controller board, I was ableto program and test the driver soft-ware directly and easily.

The final configuration consists ofthe Z8 board, 4 K bytes of expansionmemory, the EPROM-programmingcircuit of figure 3, three pushbuttonswitches, and some LEDs (light-emitting diodes) added to com-

municate with the operator. Thepushbuttons L, V, and W activate theload, verify, and write functions,respectively. The three LEDs next tothem are labeled Read, Write, andReady. Two more LEDs, labeled Tand L (for terminal and local) areplaced adjacent to the Control slideswitch. I'll explain them later.

The intelligent EPROM program-mer has two operating modes. Withthe Control switch in the L (local)position, the programmer receives allits commands through the pushbut-ton switches. With the Control switchin the T (terminal) position, the pro-grammer expects to receive com-mands from a video terminal orteletypewriter connected to theZ8-BASIC Microcomputer's RS-232Cconnector. In this terminal mode, youcan examine the buffer contents,directly change or introduce new

Number

Type

+ 5V

GND

IC1

8255

26

7

IC2

74121

14

7

IC3

7406

14

7

IC4

2716

24

12

-<Z3 WRITEPULSE

READ_/o_WRITE

^7

Figure 3: Schematic diagram of a simple EPROM-programming circuit that is intended to be driven from an external large(program-development-type) computer system.

October 1981 © BYTE Publications Inc 41

data, and execute the standard read,write, and verify functions bykeyboard commands. In addition,this mode facilitates serial entry ofdata directly into the buffer.

The local mode emulates thepushbutton operation of typical com-mercial EPROM programmers. Press-ing L (load) will cause the device toread an EPROM inserted into the ZIF(zero insertion force) integrated-circuit socket and store the data in2 K bytes of the 4 K-byteread/write-memory buffer. (The buf-fer has enough capacity to store allthe data in a type-2732 EPROM,making possible yet more versatility.)Pressing W (write) will make thedevice program the 2 K bytes of datafrom the memory buffer into anerased EPROM inserted into the ZIFsocket. Pressing V (verify) will causethe Z8 program device to comparethe contents of the buffer to theEPROM. The LEDs indicate the cur-rent status and inform the operatorwhen a function has been completed.All these operations and controlassignments are under program con-trol. Their meanings and functionscan easily be changed in software tomeet your specific requirements.

Programmer Hardware

The EPROM-programming hard-ware consists of two basic sections:memory expansion for the Z8-BASICMicrocomputer (shown in figure 4a),and the EPROM-interface section(shown in figure 4b).

After the EPROM-programmingsoftware has been written and de-bugged (which is done using theBASIC interpreter), it can itself beplaced into an EPROM, which canthen be plugged into the Z8 board's

Number

Type

+ 5V

GND

IC1

Z6132

28

14

IC2

74LS30

14

7

IC3

74LS04

14

7

IC4

74LS30

14

7

IC5

74121

14

7

IC6

7406

14

7

IC7

74LS04

14

7

IC8

8255

26

7

IC9

2716

see schematic

diag

ram

Z6132 memory socket. With the on-board read/write memory removedto accommodate the EPROM, aseparate buffer memory must be add-ed to the Z8 board to hold the dataread from or written into the 2716 be-ing processed. This can be providedby the original or another Z6132quasi-static 32 K-bit memory deviceand two other chips. ICl in figure 4ais the Z6132, and IC2 and IC3 func-

tion as address decoders. As con-figured, the 4 K-byte expansionmemory resides at hexadecimal ad-dresses 8000 through 8FFF.

The EPROM-interface hardwareshown in figure 4b is essentially thesame as that in figure 3, with a fewmore "bells and whistles." Aspreviously described, the 8255 PPI isattached to provide three parallelports. Instead of using four incremen-

TO FIGURE 4bIC4

A13 AU

FROM

Z8-BASIC <

MICROCOMPUTER

A15[S>

A14[T>

A13Qj>

A12[T>

DS[2T>R/W (2fl>

AS[2g>All[W>A10[F>

A9[Y>

A8[T>

A7/D7(j>A6/D6|T>A5/D5[6>A4/D4[T>A3/D3(T>A2/D2[n>Al/Dl[l0>A0/DO|T>

Figure 4a: Schematic diagram of the buffer-memory section of the intelligent EPROMprogrammer. This circuit expands the read/write memory capacity of the Z8-BASICMicrocomputer, and it may be used independently of the EPROM-programming inter-face.

42 October 1981 © BYTE Publications Inc

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October 1981 © BYTE Publications Inc 43

tally adjacent addresses to designatethe mode-control-register and portlocations, I conserved hardware andaddressed the four ports as follows:hexadecimal 9000, port A; hexa-decimal 9100, port B; hexadecimal9200, port C; and hexadecimal 9300,mode control.

Other differences in the circuit in-clude computer control of theread/write function and the supply ofpower to the EPROM. Rather thanmaking you manually turn off thepower to insert or extract a 2716, theEPROM programmer controls thepower through a relay. The READYLED indicates when the power is off(the LED will be lit). The three con-trol signals come from output port 2provided on the controller board. Bit

0 is the power control (0 = off,

1 = on), bit 1 is the read/write con-trol (0 = read, 1 = write), and bit 7provides the program pulse to the

one-shot (a transition from low tohigh and back to low). The Controlswitch and the three pushbuttonswitches are read as bits 4 through 7of an I/O port memory-mapped intohexadecimal address FDE8 (decimal65000). This input port is also provid-ed on the Z8 board.

The intelligence for the

EPROM programmer is

supplied by a Z8-BASIC

Microcomputer.

Software Control

The driver program for the pro-grammer is written in tiny BASIC andresides in EPROM on the controllingZ8 board. The routine is verystraightforward and can easily berewritten to run on another BASICinterpreter, should you care to con-

nect the EPROM interface to a dif-ferent computer. The entire programis too complex to cover in this article;it includes a lot of code necessarymerely for screen formatting andoperator interaction in the terminalmode. Let's confine our attention tothe less involved routines whichallow automatic programming con-trol in the local mode.

The code for the local-mode con-trol routines is given in listing 1 onpage 47. Flowcharts of the constituentparts of the listing are shown infigures 5 through 8. Essentially, theprogram consists of a supervisory in-put scanner and four subroutines.The supervisor reads the pushbuttonand slide switch inputs and transferscontrol to the appropriate subroutineto execute the corresponding func-tion. The functions include readingthe EPROM and storing the datavalues in the buffer, writing the buf-

Photo 3: Closeup of the prototypecontrol panel. The L, V, and Wpushbutton switches control theload, verify, and write functions,respectively. The T and L indica-tions next to the slide switch standfor terminal and local. In local-mode operation, no video-displayterminal or teletypewriter isnecessary, and all EPROM pro-gramming and verification can beaccomplished with only these con-trols.

( SUPERVISOR J

SET PORT 2

FOR OUTPUT AND

CLEAR VARIABLES

READ SWITCH ANDPUSH-BUTTON INPUTS

GO TO

TERMINALSUBROUTINE

GO TO

BUFFER-LOAD

SUBROUTINE

GO TO

MEMORY-BUFFER-AND-EPROM-COMPARESUBROUTINE

GO TO

BUFFER-TO-EPROM-PROGRAMMERSUBROUTINE

Figure 5: Flowchart of the command-input, user-interface section of the EPROM-programming software, as shown in listing 1.

44 October 1981 © BYTE Publications Ire

fer contents to the EPROM, compar-ing the buffer and EPROM values,and transferring control to an interac-tive routine that communicates withthe operator through a keyboard anddisplay (terminal mode). Theflowcharts indicate the sequence.

Conclusion

As the technology of EPROMmanufacturing continues to bedeveloped, I will keep a close eye onthe possible need for circuits to usenew components. Perhaps in anotherfew years I'll be writing about inter-facing and programming 1-megabyteEPROM chips.

I shall also be investigating otherprojects using the Z8-BASICMicrocomputer as a component thatcan give additional flexibility and

Text continued on page 48

(LOAD^^ BUFFER J

SET 8255 PPITO EPROM-READMODE

TURN ONEPROM POWER

SET ADDRESSPOINTERS

READ EPROMCONTENTS ANDSTORE INMEMORY BUFFER

INCREMENTADDRESS POINTERS

TURN OFFEPROM POWER

( EX'T )

Figure 6: Flowchart of the subroutine toload the EPROM programmer's buffermemory from a previously programmedEPROM chip.

Photo 4: Closeup of ZIF (zero insertion force) socket. When the lever on thelower left is in the vertical position, the two metal contacts touching each IC (in-tegrated circuit) pin are spread far apart. The IC therefore requires no (zero) extraeffort to separate the contacts during insertion or removal. When the lever isdown, as shown, the two contacts are clamped against eachIC pin, and the Ids ■-■held fast with good electrical contact.

Photo 5: Closeup of the prototype EPROM-programmer interface, Other thanthe control panel and ZIF socket, the interface essentially consists of a 4 K-bytebuffer memory and 3 programmable I/O ports. Users wishing merely to expandthe original Z8-BASIC Microcomputer need add only these sections.

October 1981 © BYTE Publications Inc 45

/^PROGRAM "\\_ EPROM J

SET 8255 PPI TOEPROM-WRITE MODE

SET READ/WRITELINE TO WRITE

TURN ONEPROM POWER

SET

ADDRESS POINTERS

»

1

SET DATA ANDADDRESS TO EPROM

PULSE CE/PGM

(PROGRAM/ENABLE)

LINE

INCREMENTADDRESS POINTERS

_NO/ALL LO

RE \.

CATIONSX

30GRAMMED

YES

SET READ/WRITETO READ MODE

TURN OFFEPROM POWER

( EX'T )

( VERIFY J

SET 8255 PPI TOEPROM-READ MODE

TURN ONEPROM POWER

SET

ADDRESS POINTERS

READ EPROM LOCATIONAND COMPARE TOBUFFER DATA

TURN ONERROR LIGHT

INCREMENTADDRESS POINTERS

( EX'T )

TURN OFFEPROM POWER

( EX'T )

Figure 8: Flowchart of the routine that verifies correct programming of the EPROM.

Figure 7: Flowchart of the routine towrite data from the buffer into a new orerased 2716 EPROM chip.

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Circle 158 on inquiry card.

Listing 1: Program routines to control various functions of the intelligent EPROM programmer, written for the BASIC/Debug in-terpreter of the Zilog Z8671 single-chip micromputer found in the Z8-BASIC Micromputer.

100 REM INTELLIGENT EPROM PROGRAMMER

102 REM USING CIRCUIT CELLAR BASIC COMPUTER/CONTROLLER BOARD

103 REM CLEAR VARIABLES AND CHECK KEYPAD ENTRIES105 @246=0 :@2=0

110 A=0 :B=0 :X=0 :Y=0

130 A=@65000

135 REM B7-TERM/LOCAL,B6-LOADfB5-WRITE,B4-VERIFY

140 IF AND(A,%80)=0 THEN 5000

150 IF AND(A,%40)=0 THEN 1000

160 IF AND(A,%20)=0 THEN 2000

170 IF AND(A,%10)=0 THEN 3000

200 GOTO 130

1000 REM READ/LOAD BUFFER SUBROUTINE

1005 REM CLEAR VARIABLES AND SET 8255 FOR I/O READ

1010 X=0 :Y=0 :A=0 :B=0

1020 @%9300=%90

1025 REM MEMORY BUFFER STARTS AT 8000 HEX

1030 @2=1

1040 GOSUB 1100

1050 @B=@%9000

1060 GOSUB 1300

1070 GOTO 1040

1100 B=(32768+X+(Y*256))

1110 @%9100=X :X=X+1 :GOSUB 1200

1120 @%9200=Y

1130 RETURN

1200 IF X=256 THEN Y=Y+1 :X=0

1210 RETURN

1300 IF B=34815 THEN @2=0 :GOTO 130

1310 RETURN

2000 REM WRITE CONTENTS OF MEMORY BUFFER INTO EPROM

2010 X=0 :Y=0 :A=0 :B=0

2015 REM SET PROGRAMMER TO WRITE MODE AND TURN ON EPROM POWER

2020 @2=3

2030 @%9300=%80

2040 GOSUB 1100

2045 REM SET DATA AND ADDRESS ON 8255 AND PULSE WRITE STROBE

2050 @%9000=@B

2060 @2=131 :@2=3

2070 GOSUB 1300

2080 GOTO 2040

3000 REM VERIFY CONTENTS OF EPROM TO MEMORY BUFFER

3020 X=0 :Y=0 :A=0 :B=0

3 025 REM SET PROGRAMMER TO READ MODE AND TURN ON EPROM POWER

3030 @%9300=%90

3040 @2=1

3050 GOSUB 1100

3055 REM COMPARE EPROM AND MEMORY — IF WRONG, TURN ON ERROR LIGHT

3060 IF @%9000<>@B THEN @2=128 :GOTO 130

3070 GOSUB 1300

3080 GOTO 3050

5000 REM ENTER TERMINAL EXERCISOR PROGRAM HERE

5010 GOTO 130

October 1981 © BYTE Publications Inc 47

RCA's remarkable new VP-3303Interactive Data Terminal turns anyhome TV into a videotex display unit.

Now you can connect your family tothe whole informative and entertainingworld of CompuServe, The Source, DowJones News/Retrieval and other time-sharing and data-base networks.

All you need is our VP-3303, amodem and a modem cable, a telephoneand your home TV.

You can get instant access to re-gional newspapers and newsletters . ..weather reports and sports results . ..computer games and more. You can usethe VP-3303 to make airline reservations... find restaurant recommendations incities around the world. Plus stock mar-ket and corporate data. Or access yourschool or business computer. You caneven send electronic mail and buyproducts.

What you have working for you isa versatile, feature-packed interactivedata terminal which can be worthfar more to you than its low price.Its unique color-locking circuitry givesyou sharp color graphics and rainbowfree characters. You get 20- and 40-character formats in one of eight col-ors and separate color backgrounds.The spill-proof, easy-to-clean keyboardis highly suitable forhostile environments.And the light touch

membrane keyboard switches give you anatural feel. With reverse video, you canemphasize certain letters, words or sen-tences. A built-in tone generator . .. plusa white noise generator... let you createeverything from the sound of explosionsto the sound of music.

The RCA VP-3303 is complete withboth RS232C and 20mA current loop in-terfaces. It has six baud rates, eight dataformats and ASCII encoding .. . versatil-ity that allows you to connect directly toa computer, as well as time-share.

The RCA VP-3303 is truly a fine video-tex terminal. And don't forget, it's madeby RCA ... the first name in television... now the foremost name in videotexterminals.

See a demonstration of the newRCA VP-3303 at your local computer orelectronics dealer, or order direct fromRCA, toll free or by mail.

Order now . .. only $389.00 (Sug-gested user price.) For more infor-mation call toll free. 800-233-0094. InPennsylvania, call 717-393-0446.Visa or MasterCard holders mayorder by phone. Or send a checkincluding $3 deliverycharge per unit plus yourlocal sales tax.

TIME-SHARING.

Text continued from page 45:

capability to an otherwise simpleproject.

Next Month:

// you've wanted to use aswitching-type power supply in yourprojects but didn't know how to goabout it, you will have an opportuni-ty to find out as I explore this topic inNovember. ■

References

1. Ciarcia, Steve. "Add Nonvolatile Memoryto Your Computer," December 1979BYTE, page 36. Reprinted in Ciarcia's Cir-cuit Cellar, Volume II. Peterborough NH:BYTE Books, 1981, page 129.

2. Ciarcia, Steve. "Build a Z8-Based ControlComputer with BASIC, Part 1," July 1981BYTE, page 38.

3. Ciarcia, Steve. "Build a Z8-Based ControlComputer with BASIC, Part 2," August1981 BYTE, page 50.

4. Ciarcia, Steve. "Program Your NextEROM in BASIC," March 1978 BYTE,page 84. Reprinted in Ciarcia's CircuitCellar, Volume I. Peterborough NH: BYTEBooks, 1979, page 39.

5. Component Data Catalog. Santa Clara CA:Intel Corporation, 1980.

6. Condra, David L. "Interfacing the S-100Bus With the Intel 8255," October 1979BYTE, page 124.

7. Gable, G H. "Zapper: A Computer-DrivenEROM Programmer," December 1978BYTE, page 100.

8. Greene, Robert, George Perlegos, PhillipSalsbury, and William Morgan. "The Big-gest Erasable PROM Yet Puts 16,384 Bitson a Chip," Electronics, March 3, 1977,page 108.

9. Greene, Robert, and Frank Louie."EPROM Doubles Bit Density Without Ad-ding a Pin," Electronics, August 16, 1979,page 126.

10. Lewin, Douglas. Theory and Design ofDigital Computer Systems, second edi-tion. New York: Halsted Press, a Divisionof John Wiley, 1980.

11.Smith, Roger L. "More Information onPROMs," May 1976 BYTE, page 28.

Editor's Note: Steve often refers to previousCircuit Cellar articles as reference material forthe articles he presents each month. These ar-ticles are available in reprint books from BYTEBooks, 70 Main St, Peterborough NH 03458.Ciarcia's Circuit Cellar covers articles appear-ing in BYTE from September 1977 throughNovember 1978. Ciarcia's Circuit Cellar,Volume II presents articles from December1978 through June 1980.

To receive a complete list of Ciarcia CircuitCellar kits available from the MicroMint, circle100 on the inquiry card.

Circle 322 on inquiry card.

New from HIPL0TM6-pen plotting for as little as $1480*.

And you can retrofit your present single pen HIPL0T for only $395.

The new HIPL0T DMP Series6-pen option makes high perfor-mance multi-pen plotting affor-dable. It's available on the DMP-2,3 or 4 models in the HIPL0Tfamily so you can enjoy the ad-vantages of multi-colored plots onsurfaces of 8Vi" X 11" (DIN A4)or 11" X 17" (DIN A3). Ofcourse, you also get the standardHIPL0T range of capabilities suchas intelligence, controls, interfacesand resolutions. There's a model forvirtually every plotting application.

line which made low-cost, highperformance digital plotting areality.

Big Performance in a Small Plotter

Since it's introduction, theHIPL0T DMP Series has been rec-ognized as the innovative plotter

TM Trademark of Houston Instrument.U.S. Suggested retail prices.Centronics' registered trademark olCentronics Data Computer Corp.

Now, with our new 6-penoption, there's an exciting newdimension in the DMP Series' ver-satility. Imagine standard modelswith RS-232-C and parallel inter-faces, intelligent models withRS-232-C or Centronics® compa-tible interfaces, a choice of con-trols, resolutions, and pen speeds.Add to this the ability to plot with6-pens on paper, vellum or Mylar(ideal for overhead projectors) andyou have the ultimate plotterprice/performance combination— the perfect choice for the useror OEM.

Circle 169 for literature

Circle 170 to have representative call

Easily Retrofitted to ExistingHIPL0T Models

If you already have a singlepen DMP-2, 3 or 4, don't despair.For as little as $395* you canupgrade these models with our6-pen conversion kit. It's simple todo . . . and the complete changecan be made by the user in onlysix minutes.

So why wait? Let us send youcomplete information on thisbreakthrough in affordable, multi-pen plotting. Contact HoustonInstrument, One Houston Square,Austin, Texas 78753. (512) 837-2820.For rush literature requests, outsideTexas, call toll free 1-800-531-5205.For technical information ask foroperator §5. In Europe contactHouston Instrument, Rochesterlaan 6,8240 Gistel, Belgium. Phone059/27-74-45.

houston instrument

GRAPHICS DIVISION OF

BAUSCH&LOMB

Ultra-Low-Cost Networkfor Personal Computers

Ken Clements and Dave DaughertyPacific Polytechnical CorpPOB 2780Santa Cruz CA 95063

Ten years ago, computer "hackers"listened with glee to predictions thattechnological advances would soonallow them to buy their very owncomputers. Indeed, the seerspredicted, the computers of the futurewould fit into a spare bedroom orbasement and wouldn't even requireair conditioning. The word went out:start saving $100,000 to be readywhen that great time came.

The time came with a vengeance.Today you can hardly take twentypaces around a technical organiza-tion, school, or office without bump-ing into or being addressed by yetanother computer.

One of the sad outcomes of this ex-ponential growth was creation of thecomputer junkie, the unfortunatesoul who went out and bought eachof the newest computers he or she

could afford. The junkie ended upwith a basement full of equipmentand a computer habit that could besatisfied only by more spending.

Just when the future was lookinggrim for these computer junkies,salvation took form and appeared oncollege campuses. Perhaps the bestexplanation came from a recruiterfrom the giant Xmumblex Corp, whotook a young graduate aside andwhispered, "I have just one word foryou: networks."

The big-computer companies andan army of computer scientists ap-parently will be going network crazyfor the next ten years. This develop-ment thrills the computer junkiesbecause it provides more computer"stuff" to get excited about. And, thejunkies calculate, if they could gettheir own personal networks going,

ULCNET TWO-CONDUCTOR CABLE

Jr

•2K

V

v

V

D,

I r

RECEIVED TRANSMITTED SIGNALDATA DATA GROUND

RECEIVED TRANSMITTED SIGNALDATA DATA GROUND

RS-232

DB25P

CONNECTOR

RS-232

DB25P

CONNECTOR

Figure 1: Simplest version of ULCNET. The addition of a diode, cable, and terminatingresistors converts RS-232 ports into a basic network for personal computers.

they might be able to string togetherall the "coldware" collecting dust intheir basements.

What stops most people from goingahead with their own networks iscomplexity, both in terms of cost andtechnical considerations. A typicalcoaxial network "box" may be as dif-ficult to build and interface as was thecomputer you wanted to network.This stumbling block is particularlylarge for the computer junkie whoowns no two pieces of hardware thatare the same. He must come up with anew interface for each one.

But almost all those pieces of hard-ware have at least one RS-232 serialport. RS-232 was designed to providepoint-to-point communication, and itrequires some central manager "box"to produce a network. But with as lit-tle as one diode per port, tworesistors for the ends, and a — 12-volt(V) source, you can turn RS-232 intoULCNET, the Ultra-Low-Cost Net-work.

Simple Technique

The primary technique for thistransformation is shown in figure 1. Itis amazingly simple: just connect adiode in series with the transmit line,then connect the receive line and thediode to your cable. At the ends ofthe cable you will need resistors to"pull down" the line to —12 V and tohelp soak up reflections. Serial com-munications via RS-232 are usuallynot too fast, so the type of cable andexact terminations are not critical.

SO October 1981 © BYTE Publications Inc

Please call

(213) 883-8594.

Our Epson pricesare so low,

we're not allowedto print them.

$ 1

309530006070

SERIAL INTERFACE (2K BUFFER)SERIAL CABLE Male to MaleDOT RESOLUTION GRAPHICS

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EPSON MX-80 SCALL EPSON INTERFACES & OPTIONS

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EPSON MX-80 F/T $CALL

Same features as the MX-80 plus Fric-tion Feed. Adjustable removable trac-tor is standard for ease of handlingforms and single sheets.

EPSON MX-100 F/T SCALL

Same features as the MX-80 & MX-80F/T but on 15'/2 inch carriage for print-ing 132 columns with standard 10 cpifont or 232 columns in the com-pressed character font. The MX-100 iscomplete with Dot ResolutionGraphics 31245 La Baya Drive, Westlake Village, California 91362

Circle 13 on inquiry card.

1493090

134040

We built a reputation on ourprices and your satisfaction.

We guarantee everything we sell lor 30 days. II anythingis wrong, just return the item and we'll make it right.And, of course, we'll pay the shipping charges.

We accept Visa and Master Card on all orders. CODaccepted up to $300.00. We also accept school pur-chase orders.

Please add $2.00 for standard UPS shipping andhandling on orders under 50 pounds, delivered in thecontinental U.S. Call us for shipping charges on itemsthai weigh more than 50 oounds. Foreign, FP0 and AP0orders please add 15% for shipping. California res-idents add 6% sales lax.

BYTE October 1981

51

ULCNET SHIELDED, TWISTED-PAIR CABLE

RED WIRE .--SHIELD

RED WIRE

OOOOCK

A 1N4933

V &

1N4933

RECEIVEDDATA

TRANSMITTEDDATA

SIGNALGROUND

RECEIVEDDATA

TRANSMITTEDDATA

RS-232

DB25P

CONNECTOR

RS-232

DB25P

CONNECTOR

i L <J

SIGNALGROUND

Figure 2: ULCNET for two-wire shielded cable. In this version, a singleto the pull-up resistors via one conductor of the cable.

■ 12 V power supply is specified, and power is transmitted

For most applications, it is easy touse shielded twisted-pair cable for thenet. This allows one of the wires inthe pair to carry the —12 V needed bythe termination resistors at the end of

the cable. An example of wiring thetermination is shown in figure 2. Thistechnique assumes that somewherealong the line, the black wire in thepair is connected to —12 V and the

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shield is grounded.

When characters are sent throughan ULCNET port, they are received atall the ports on the net, including theport that did the sending. However, iftwo or more ports send differentmessages at the same time, thetransmitting ports will each receivesomething other than what they sent:the logical OR of the two messages.This allows an extremely importantproperty, namely collision detection(a property also used in Xerox'sEthernet).

The ULCNET uses the fact that anRS-232 port holds its transmit line atnegative voltage when not transmit-ting, and then pulses the transmit linepositive at the start of a character.The RS-232 standard defines apositive level as a transmitted 0 and anegative level as a binary 1. In otherwords, a character starts with a 0,followed by a byte of code transmit-ted low-order bit first. At least onebinary 1 is inserted after each byte-long character, and it is called thestop bit.

The termination resistors on theULCNET provide the negative level,and each port may "pull" the line to apositive level by the start pulse of acharacter. In terms of bits, theresistors supply the Is, and the portssupply the Os.

52 October 1981 © BYTE Publications Inc

Circle 354 on inquiry card.

In LanguageLies The Future.

'aui Lutus creates language. Language tor tne tuture.

From him we have Apple Writer, Apple World and MusiComp.His software was used by the Viking MarsLander team and other advanced

space programs.

For the past three years he haapplied himself to the developmof more efficient and powerfulcomputer languages tohelp him with his work.These new languagesof the future are now \

available for your use \

exclusively from Insoft. \

e new world ofming from Insofte dealer.

■uny compn

• Floating pointTranscendental functionsStrings and arrays

• Hires, Lores and Turtlegraphicsm Music

Far more compact and approachable thanPascal, TransFORTH II is both recursive andstructured and easier to use than BASIC.

Over three years in development, this highlevel language enables you to program inEnglish with far greater speed and conven-ience than ever belore possible.

TransFORTH II. A transformation in

Available today.

package /AjjJDj

introductory

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gistered trademarkpple Computer, Inc.

The languages of the future. Th

259 Barnett Rd. / Unit 3 / Medlord, Or 97501 / (503) 779-2465

• Object files to 18KSource files to 37K

• Cursor based screen editor

• Upper and lower case text entry

• Nested macro instructions

• Local, global and universal labels

• Comprehensive error trapping

The enormous file capacity of ALD SystemII assures you of the ability to developvirtually any imaginable software system.And you can do so with ease since ALDSystem II edits with the simplicity ot a wordprocessor.

ALD System 11. Powerful yet convenient.The first choice of professionals.

The best comes last. Both newprograms are available for theApple II or Apple III.

Circle 179 on inquiry card.

The speed and distance limits of theULCNET come from a combinationof the drive-current limitations of anRS-232 port and the load eachreceiver puts on the net. The limitslead to a three-way trade-off ofdistance, speed, and number of re-ceivers. For example, you might usethe ULCNET at 19,200 bps (bits persecond) for six devices separated by20 feet, or you might connect threedevices with two miles of wire andrun at 300 bps.

Improvements

Some simple modifications can bemade to expand the network capabili-ty. The first modification gets thenumber of receivers out of the trade-off equation. Figure 3 shows an alter-nate ULCNET connection in which anop amp (operational amplifier) isused to buffer the incoming signal.This reduces to almost nothing theload each node places on the net-work, thereby allowing as many con-nections as desired on the net.

Some RS-232 ports have +12 Vand —12 V supplied on pins 9 and 10of their DB25 connector (these can beused to power the op amp). Most,

TO ULCNET

however, do not, so the user will needto run a pair of wires to the powersupply of the computer. If some otherpower source is used, the user mustbe sure its ground reference is thesame as pin 7 of the RS-232 port.

Figure 3 also shows a circuit thatdrives the DTR (data terminal ready)input of the RS-232 port. This circuitis used to detect activity on the net,and it will assert (pull high) DTR ifthe net is busy. The circuit works bycharging Cl, a 0.1 /*F capacitor dur-ing the start bit of a character. Thecapacitor will then discharge throughthe 330-kilohm (kfi) resistor Rl whencharacters are no longer being trans-mitted. The choice of values for thesetwo components is set by the slowestdata rate to be used on the net. Thechoice shown was picked for 1200 bpsoperation. If 2400 bps is desired as thelowest rate, then halve Rl's value.The resistor can be scaled in this man-ner for the lowest transfer ratedesired. Table 1 suggests resistorvalues for various data rates, but planto experiment.

The purpose of the busy flag circuitshown in figure 3 is to relieve the soft-ware of checking the condition of the

GROUND DATA

■lOOfl

1N914

Rl

330K +12VIFROM RS-232 PIN9)

A

■Cl/TS0.1/*F

1N4933

A

SIGNAL TRANSMITTEDs GROUND DATA

DTR

v1

RECEIVEDDATA

RS-232

DB25P

CONNECTOR

Figure 3: Simple modifications expand network capacity. An operational amplifierreduces the load placed on the net by each node, so that a virtually unlimited number ofnodes can be used. Resistor Rl and capacitor Cl control the op-amp comparator tosignal that the network is busy. The components shown can be used with speeds as lowas 1200 bps; see table 1 for alternate selections.

Data Rate

Size of R,

(bps)

(Ml)

1200

330

2400

160

4800

82

9600

39

19.2 k

22

38.4 k

10

76.8 k

5.1

153.6 k

2.2

Table Is Suggested

resistor values for

running ULCNET at various speeds.

Experimentation is

suggested.

net, and to provide a signal that canbe used with an interrupt-drivensystem. (These techniques are dis-cussed later.)

Aiming for Speed

Figure 4 is included for those whocrave speed. Here, the drive limita-tion is overcome by using a powerFET (field-effect transistor) to drivecoaxial cable. The cable can be eitherstandard 50-fl coax, or the 75-fi coaxcommonly used in cable TV opera-tions. Whichever you choose, youmust use a matching resistor (50 0 or75 0) on each end of the cable.

In this form of the ULCNET, thelogical 0 is represented by a +12 Vlevel, and the logical 1 is at 0 V.The same busy-detect circuit is used,and all of the network techniques willremain the same. This version ofULCNET is included for those whohave very fast controller devices ontheir ports and want to operate in the50 kbps to 1 Mbps range.

To make this fast version work, itis important to have a very solidsource of +12 V that can put outabout one amp for a very short time.The fuse included in figure 4 is meantto shut down the connection if thecomputer turns on the power FET andleaves it on. If not corrected, this er-ror condition would cause the entirenet to halt.

One way to set up a network isshown in figure 5. This setup wouldallow all the computers to share thehard disk and the printer. The com-puter directly connected to the harddisk and printer would be partially

54 October 1981 © BYTE Publications Inc

THE B810 RAM

engineered for excellen

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FEATURES

• Byte or Word width operation

• Extended Addressing or PortSelect

• 150 ns Access, 270 ns Cycle(B Version)

• 200 ns Access, 335 ns Cycle(AVersion)

•Full DMA capability withtransparent refresh

• Precise memory timing module

• Low Power

• Meets IEEE 696 specifications•Four-layer board

^ Assembled & Tested with l Year Warranty, *Introductory Price valid through 30 Sept., 1981

The B810 RAM represents one of the best solutions forapplications requiring compact design and speed for re-markably low cost. Suitable for a wide range of commer-cial applications, the B810 RAM is form, fit and function-ally compatible with the proposed IEEE 696 (S-100) busstandard. It automatically provides byte or word widthaccess using the sXTRQ* signal. It features the AMD 2964Dynamic Memory Controller and a new memory timingmodule designed for the B810 by Engineered Compo-nents Corp. for precise timing. Its four layer board withfull ground and power planes provides noiseless opera-tion. As an integral part of the AB Digital B800-series, theB810 RAM provides full DMA capability. Designed to beas universal as possible, the B810A RAM will work withmost S-100 cards using a Z80 or Z8000, and the B810B(with optional byte parity), works with Alpha Micro,Cromemco, Northstar, and all S100 CPU cards.

Available through California Digital (toll-free ordersonly 800-421-5041) and other fine distributors, or direct.Specification sheets on request. Manuals may be pur-chased separately for $25.00 refundable on order.

COMING NEXT MONTH: THE B880 80ns 64K/32K STATICRAM

The B800 series of 8-bit cards provides the OEM with a com-plete line of 6 MHz computer cards. All peripheral controllersare intelligent. This series includes the B800 CPU; the B820 SCCSerial Communications Controller; the B830 HDC Hard DiskController; the B840 FDC Floppy Disk Controller, and otherswhich will be announced.

The B8000 series provides a complete line of 16-bit 4 and 6MHz cards in three formats: double-height SI00, MultiBus andthe new Zilog ZBI bus. As with the B800 series, all peripheralcontrollers are intelligent with their own processors and mem-ory. The B8000 series includes the B8000 CPU (Z8001-based);the 1 Megabyte B8100 RAM with optional EDC; the B8200 SCCSerial Communications Controller; the B8300 HDC Hard DiskController; the B8400 vVDC Winchester Disk Subsystem; andothers to be announced.

AB Digital Design Labs products are designed to provide tech-nological leadership and industrial-grade quality with unex-celled performance. Before you buy any computer product, weinvite you to examine our spec sheets and manuals. We thinkthe choice will be clear.

Digital Design

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Circle 2 on inquiry card.

BYTE October 1981 55

TO ULCNET

GROUND

IOjiFTANTALUM

^

IK-W\/-

IK

-vw-

1/4 ASLO-BLOFUSE——<f\_o

+ 12V ( FROM RS-232 PIN 9)

•lOOfl

330 K

VMOS POWER FETSILICONIX VN35AB

ORINTERSIL IVN5001TN0

1N914

+ 12V(FROM RS-232 PIN 9)A

•4.7K

10K-WV-

1* oV

-12V

(FROM RS-232PIN 10)

&

SIGNAL TRANSMITTED

GROUND DATA

V V

V

DTR

RECEIVEDDATA

RS-232

DB25P

CONNECTOR

Figure 4: Fast version of ULCNET. The primary limitation of driving power is overcome by installing an output transistor at eachport. The transmitter shown may draw as much as 1 A from the —12 V supply, for short periods.

dedicated to servicing the requests forthese resources.

Design Issues

Now that we've discussed the hard-ware for the ULCNET, let's look atsome of the issues involved in design-ing software for the network. Theseissues are: node-addressing concepts,message formats, task layering, low-level transmission and reception,communication protocols and errorrecovery, dialogue pipes, specialtypes of networking communica-

—I

HARD DISK

PRINTER

COMPUTER

l_.

tions, and networking under multi-tasking operating systems.

First let's define a node as anydevice connected to the ULCNET thathas the ability to transmit informa-tion, receive information, or both.

If there are more than two nodes ona net, some mechanism is needed touniquely specify the destination oftransmitted information. This need isfulfilled by assigning to each node aunique numeric address. A singledigit may be sufficient to specify thenode for which a message is intended.

COMPUTER

COMPUTER

ULCNET

7

Figure 5: One possible ULCNET configuration. In this example, the mass storage andprinter on one computer system can be shared by several other systems.

Many mechanisms can be used toinform the node's software of its par-ticular address. The possibilities in-clude establishing a switch setting onan input port, including the informa-tion in the software for each node(but each node would then need aunique version of the network soft-ware), or having the software querythe user for an address during ini-tialization.

An address does not necessarilyhave to be a number, as long as it canbe uniquely recognized. It could be acharacter string such as EVA orSHIRLEY, but you must be willing topay the cost of pattern matching inorder to adopt this scheme.

A nameserver mechanism allowsthe nicety of character strings for ad-dresses without sacrificing the advan-tage of number matching for decod-ing addresses. The nameserver con-sists of a file and a program on a nodewith mass storage that associates anASCII (American Standard Code forInformation Interchange) string withan address number. The nameserver

56 October 1981 © BYTE Publications Inc

Circle 319 on inquiry card.

Radio Shack,The Leader in Small Business ComputersAlso Has Computers for Your Home!

Introducing the Lowest Cost

Color Disk System Ever—

Radio Shacks TRS-80

Radio Shack now offers disk drives for our popularTRS-80 Color Computer. Now you can have superbhigh-resolution color graphics and fast, "on-line" ac-cess to large amounts of data.

Only $1198. Our new $599 disk kit makes our TRS-80Color Computer with 16,000 characters (16K) of inter-nal memory and Extended Color BASIC language aversatile, low-cost computing system that's ready toattach to any TV (not included).Stores 156,000 Characters! Just plug in the ProgramPak<S> controller to add disk storage to the ColorComputer. The Disk Operating System—an en-hanced version of the Color Computer's ExtendedColor BASIC language—is completely contained inthe Program Pak, so you get a full 156K-bytes ofon-line storage.

Easy to Use. The 16K TRS-80 Color Computer lets youcreate sophisticated color diagrams, business chartsand even simple animation—using just a few simpleone-line commands! This gives experienced program-mers incredible power, yet makes it easy for beginners,too. We take you from the ground up with over 500pages of easy-to-read documentation.Instant Fun and Games. And just for fun, you canplug in any of our game cartridges. Battle starships inouter space, conquer dinosaurs from a prehistoricworld, or just brush up on your chess.Fully expandable. Your TRS-80 Color Computer DiskSystem can expand with up to four drives for over626,000 characters of storage! And the additionaldrives are only $399 each. Add up to 16K more mem-ory, a printer and other accessories anytime.

Radio Shack's TRS-80—The Best-SupportedMicrocomputer in the World!

The TRS-80 line of computers is backedwith a wide selection of accessories, soft-ware, and service. We can even show ^you how to get up-to-the-minutenews, current stock market reportsand even electronic mail using yourTRS-80! It's all available today atovet 8000 Radio Shack stores anddealers, and at 185 ComputerCenters nationwide.

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SOT

TOADDRESS

FROMADDRESS

MESSAGENUMBER

BYTECOUNT

MESSAGE1 D

DATA

CHECKSUM

Figure 6: Proposed message format. Various fields are included in each message to helpthe network software ensure reliability of the system.

accepts requests for registration,deregistration, and name queries.

Special generic addresses also canbe set aside for special purposes. Forinstance, the nameserver could beassigned a generic address to be usedby all nameserver-related messages,making it unnecessary to know whichnode the nameserver is actually on.

Another generic address could beset aside to represent a broadcastmessage—one that all nodes on thenetwork would want to receive. Atypical use of a broadcast message issending a company-wide memo to allemployees on the network. Thegeneric address eliminates the need toaddress the same memo to each per-son on the net.

Special types of nodes such asmass-storage nodes or printers canhave their own addresses. For exam-

ple, the address M might be reservedfor the printer node. If there is onlyone printer on your net, M wouldmean that printer. If there is morethan one printer on the net, an addi-tional field called the logical printernumber could be used to specify theprinter for which the message isdestined.

Message Formats

A message is a predetermined se-quence of fields by which two nodescommunicate. A message normallyconsists of several parts: the header,the body, and some kind of error-checking mechanism, such aschecksum, at the end.

The structure allows for muchvariation. The basic component forconstructing a message usually is abyte. A field is defined as one or more

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bytes that designate a particular sec-tion of a message. Typical fields in amessage are shown in figure 6 and ex-plained below.

• SOT: start of transmission. Thisbyte is useful for informing allreceivers that the beginning of amessage is now on the net and thatthe next byte will be the address byte.Obviously, the byte must not be con-fused with bytes in the middle of amessage.

• To Address: the address of the in-tended receiver.

• From Address: the address of thenode that transmitted the message.As will be shown later, this field isimportant for sending acknowledgments back to the transmitter.

• Message Number: a unique numberthat distinguishes one message fromthe next. The usefulness of this fieldwill be illustrated in the sections ofthis article dealing with duplicatemessages.

• Bytecount: tells a receiver howmany bytes to expect in the messagebody. It can be used as a receive loopcounter, to be decremented each timea byte is received. When the counterequals zero, the user knows thechecksum byte will follow im-mediately.

• Message ID: distinguishes threetypes of messages within a networksystem. The data message containsthe essential information to betransmitted from one node toanother. The message acknowledg-ment acknowledges a data message,and the third type of message,ACKACK, acknowledges a messageacknowledgment.

• Data: zero or more bytes of infor-mation that follow the Message ID.

• Checksum: the error-checking byte,computed as the n-bit sum of all thebytes in the message (except the SOTbyte and the checksum itself). Thetransmitter sums up all the bytes in itstransmitted message and "ships out"the lower n bits of that sum as the lastbyte of the message. Meanwhile, thereceiver does the analogous operationon the message it receives. If all thecharacters were received correctly,the receiver's lower n-bit sum shouldmatch the transmitter's checksum.

58

October 1981 © BYTE Publications Inc

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Layering the Tasks

The network software can bebroken up into three separate layersfor implementation (see figure 7).These layers are the basic transmitterand receiver subroutines, the pro-tocol layer, and the application pro-gram. Breaking up the network soft-ware in this manner is useful becauseit allows the implementer to concen-trate on a subset of network functionswithout having to give much con-sideration to the rest of the functions.As an added benefit, the layeredstructure limits the software modifi-cations needed in order to bring upnetworking capability for particularnetwork tasks and particularmachines.

As an example, let's say networksoftware is to be brought up on twoof the same type of microcomputers,each having a different serial inter-face. Subroutines in the transmit-ter/receiver layer that specificallydeal with the serial interface are theonly parts of the network softwarethat need changing. On the other end,a printer-application program and adisk-write program should be able touse the same protocol layer andtransmitter/receiver layer.

The Transmitter

A buffer and a byte count are thenecessary parameters this routineneeds from the protocol layer. Thetransmitter should neither know norcare what type of message is in thebuffer. First, the transmitter will needto know if anyone else is currently us-ing the network. In an interrupt en-vironment, this can be determined bya flag set when a character is receivedand reset when a carrier-detect inter-rupt occurs. If the flag is reset,therefore, it shows that the network isnot in use.

If the transmitter is to be im-plemented without the aid of inter-rupts, it will be necessary to wait thelength of time needed to receive onecharacter (based on the data-transferrate). If no characters are received inthis time, it is assumed no one is inthe middle of transmission.

Once it has been determined thenetwork is not busy, the transmittermust send out the SOT field. A

APPLICAT iGM PROGRAM

PROTOCOL LAYER

TRANSMITTER-RECEIVER ROUTINES

Figure 7: Network protocol is based onthe layer concept. Applications programsdeal at a high level by letting the under-

; /i/t/i'fs (/u the dirty work

potential "race" problem resulting ina collision could occur at this point,since two transmitters could con-ceivably start this transmissionsimultaneously.

Because the network is set up sothat transmitters receive what theytransmit, the received charactershould always be compared to theharacter that was just transmitted, llthe two characters do not match acollision has occurred. Later, we willdecide how to recover from such acollision.

Assuming the transmitter receivedwhat it transmitted, it continues to..■ml tun bytes until all, including 11it-checksum, have been sent. II theii msmitter is interrupt-driven, it m.i\want to set a flag to inform the pro-tocol layer that transmission was suc-essful. For a transmitter runningwithout interrupts, this informationcould be returned as a parameter tothe routine that called the transmit-ter.

The Receiver

A receiver activated by interruptswill be able to synchronize with thebeginning of a message by the carrier-: if( I inti'i i up! th.it oc( ins .ittei tinend of any message. Receiverswithout interrupts or latched carrier-detect pulses must repeatedly waituntil a whole character time has goneby without receiving anything. Thenext field to be received should be theSOT field. II it is not, it will benecessary to go back to the previousstep until an SOT is detected.

Once the SOT is detected, the nextfield should be the Destination Ad-dress. When this field is received, itshould be compared with thereceiver's own address to determinewhether the message is intended forthis receiver. If your network sup-ports broadcast messages, all

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receivers must check to see if themessage is a broadcast message. Ad-ditionally, printer and disk storagenodes must also check to see if thedestination address is their genericaddress. If no address match exists,the receiver should go back to hunt-ing for an SOT field (unless thisreceiver is a gossip monger).

If the message is addressed to a par-ticular receiver, the address and allsubsequent bytes should be receivedand summed together for comparisonwith the checksum byte at the end ofthe message. If your particular net-work uses parity, the message shouldalso be checked for each characterreceived. The receiver should not carewhat type of message was received; itshould simply inform the protocollayer of receipt. With an interrupt-driven receiver, a flag can be set atcompletion to inform the protocollayer. Additional information, suchas whether any errors occurred dur-ing the message, could also be com-municated to the protocol layer viacommon memory. If the receiver isnot interrupt-driven, this informationcan be passed back as parameters tothe protocol layer.

The Protocol Layer

For the following discussion,source will be defined as the node thattransmitted the original message, anddestination as the node to which themessage was addressed.

When computer A sends a messageto computer B, there is no guaranteethat computer B will receive it. Manythings could go wrong. There mightbe a loose connection somewhere.Computer B might not be running, orit might not be listening to the net.Computer C could start transmittingat the same time as computer A.

Protocol schemes detect and cor-rect such situations. Protocol isbasically a conversation between asource and a destination, trying to en-sure that what the source transmittedwas actually received by the destina-tion.

The simplest protocol is one inwhich the source sends a message to aspecific destination and assumes themessage arrived. If your network is ingood working order and you know

that a particular destination is run-ning properly, this protocol will besufficient most of the time. You prob-ably would want to use this protocol,for example, when you are sendingmessages to your friend Carol, who isusing computer B. If she is there, shewill probably send a message back,thereby acknowledging that shereceived your message. You'd alsouse this protocol for broadcastmessages, to prevent the net from get-ting jammed by everyone trying tosend acknowledgments at the sametime.

When you are doing things on yournet, such as writing a file to a disk,assuming the file got there is notenough. You need some realacknowledgment that the file got tothe disk. If no acknowledgmentcomes back from the destination, or ifthe destination returns to the sourcean acknowledgment stating that thedisk is full, the source will have totake some error-recovery measures.These are discussed later.

What happens if the destinationreceives a correct message and sendsback an acknowledgment that is notreceived by the source? In this case,the source thinks its original messagedid not get through, but it actuallydid. To avoid this situation, anacknowledgment of an acknowledg-ment received (ACKACK) can beadded to the protocol. If after sendingan acknowledgment, the destinationdoes not receive the ACKACK, it willhave to take some kind of error-recovery action.

What happens if the source receivesthe acknowledgment and sends theACKACK, but the destination doesnot receive the ACKACK7 Somebodyhas got to have the last word, andthere can be no guarantee that amessage and all its associated pro-tocol are transmitted and receivedsuccessfully. Especially on a low-speed network, the criterion fordeciding how much protocol to use is"as little as possible for a particularapplication." An intelligent systemmight provide all three types of pro-tocol (ie: message, message-ACK,and message-ACK-ACKACK) andallow the application program todecide which one to use.

62 October 1981 © BYTE Publications Inc

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Error Recovery

What should be done when amessage was sent and noacknowledgment came back? Orwhen an acknowledgment was sentbut no ACKACK came back? Boththese cases call for a timingmechanism. A source that transmit-ted something and is expecting a replyfrom the destination must wait a cer-tain amount of time for that reply tocome back. If the reply does not comeback within that time, it will beassumed an error condition exists.

How long should this time be?There is no way to guarantee that adestination really did receive themessage and will transmit anacknowledgment within the time thesource has set. The waiting time,then, should be more than longenough to cover any reasonable situa-tion.

Once the source has waited a setamount of time without receiving areply, a reasonable action would beto retransmit the original message atleast once more, and again wait thespecified amount of time for a reply.The same strategy could be used bythe destination when it sendsacknowledgments and waits for anACKACK. If you are doing your net-work without the aid of a hardwaretimer, you will need a time-countingsubroutine that continually checks tosee if a reply was received, anddecrements the counter. If the counterreaches 0 before a reply is received,then a timeout error exists. If yoursoftware has access to a hardwaretimer, you can use it to set an inter-rupt.

If no reply is received afterrepeated attempts to transmit amessage, there is nothing to do butgive up and report the problem to theprogram that initiated the networkcall.

This retransmission scheme in-troduces another problem. Supposethe source sends a message that isreceived by the destination, but thedestination sends back anacknowledgment that is neverreceived by the source. After timingout, therefore, the source retransmitsthe original message, and the destina-

tion receives it a second time. TheMessage Number field, along with theFrom Address field, can be used tocorrect such situations.

All receivers should keep a list ofthe last n messages received. The listneed contain only the messagenumber and the From Address. Whena new message is received, the listshould be examined for a match. If aduplicate is detected, the messageshould be "dumped," but the ap-propriate response should be sentback to the transmitter of theduplicate message. If the duplicatewas an original message, anacknowledgment should be sentback, or if the duplicate message wasan acnowledgment, an ACKACKshould be sent back.

Collisions are another issue.Assuming that all transmitters checkthe state of the network before start-ing transmission, collisions can hap-pen only when two or more transmit-ters start their transmissions withinone character time of each other.When collisions happen, all transmit-ters involved should immediatelystop transmitting and allow the net-work to return to the "not busy" con-dition.

Now some kind of mechanism isneeded to tell colliding transmitterswhen they can start transmittingagain. If they all wait an equalamount of time, they will collideagain. Therefore, they must all waitdifferent lengths of time.

One way to ensure this setup is toestablish a priority order based onnode address. If a node with the ad-dress of 1 collides with a node withthe address of 3, then node 1 will waitone unit of time before attemptingretransmission, while node 3 will waitthree units of time. One problem withthis scheme is that under heavy loadconditions where collisions are morefrequent, nodes with high addressnumbers may never be able to get amessage through because they mustwait so long after each collision.

A fairer scheme would be one inwhich each node has a random-number generator guaranteed tocreate a unique sequence of randomnumbers. All nodes would then have

64 October 1981 © BYTE Publications Inc

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equal priority in retransmissions aftercollisions.

A Typical Application Program

As an example of a typical applica-tion program, let's consider a requestto a filing system on a hard-disknode.

The "save" request would firstwant to send to the filing system amessage containing the file name andthe number of sectors to be saved.The request probably would ask theprotocol layer to expect anacknowledgment and allow the pro-tocol layer to take care of retransmis-sions if necessary. Along with theacknowledgment would come infor-mation from the filing system in-dicating whether or not the requestcan be accommodated. If it cannot beaccommodated, the request programmust report the failure to its caller.

If the request can be accom-modated, the save request programmust break up the file to be saved intoconvenient blocks (probably a disksector). When errors occur duringtransmission, it is more economical toretransmit small blocks than largeones. In either case, the save requestshould send an ACKACK to the filingsystem to say it agrees to what the fil-ing system considers the state of therequest.

Once the file has been partitionedinto blocks, the save request shouldhand them in sequence to its protocollayer for transmission to the filingsystem. The request should ask itsprotocol layer to expect anacknowledgment for each blocktransmitted. Each block should have

a unique number that can be checkedby the filing system against blocknumbers already received. In thismanner, duplicate blocks can bedumped.

By the value of the last blocknumber, both parties know when thefile transfer is completed. If im-plementation is done in a straightfor-ward manner, the last block numbershould equal the corresponding fieldin the original request message.

The save request should ask theprotocol layer to send an ACKACKto the filing system when it submitsthe last block for transfer. Uponreceipt of this ACKACK, the filingsystem can be sure it will not be get-ting a retransmission of the lastblock, and it can close the file andforget about the request.

When extended conversations aretaking place between two nodes onthe net (as in the previous file transferexamples), the network can be madeto appear constantly busy by neverallowing more than a character timeto elapse between messages. In thisway, no other user on the networkcan interfere with the conversation.

If the data rate is controlled bysoftware on the two conversingnodes, you might consider increasingthe rate after the initial conversa-tional link has been established. Therate could be increased beyond what'snormally acceptable to every node onthe network, but it must be changedback after the conversation is com-pleted. While the process is going on,every other node on the networkshould recognize it as a network-errorcondition. Because the nodes have

not seen a transition from a busy netto a nonbusy net, they will not belooking for an SOT field anyway.This scheme can get a little trickywhen attempting to end a conversa-tion, especially if the lastacknowledgment or ACKACK didnot get through but the data rate onone node has already been reduced toits former value.

Multitasking Environments

Networking in multitasking en-vironments raises many issues thatcannot be considered here, but a fewobvious ones should be pointed out.

The protocol layer probablyshould be set up as a process by in-troducing another parameter to in-dicate whether the application pro-gram will "go to sleep" waiting for areply or acknowledgment. The pro-tocol layer would then have to givethe application program a "wake up"by indicating whether the messagegot through to the receiving process.

Since messages could in this way beaddressed to one of several processeson a node, the address fields for Toand From addresses would need to beextended to include a Process IDnumber.

The software design presented inthis article reflects only one of manypossibilities. For more information,or for software if you don't want towrite your own, contact CheshireSoftware, POB 2780, Santa Cruz CA95063.

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A-26 DISCUS M26A-20 DISCUS M20A-10 DISCUS M10

$3037.00$3193.00$2400.00

FLOPPY DISK SUBSYSTEMS

F-1118 DISCUS IF-1218 DISCUS 2DF-2218 DISCUS 2 + 2

TWO DRIVE SUBSYSTEMS

$ 816.00$ 888.00$1105 00

F-1128 DISCUS IF-1228 DISCUS 2DF-2228 DISCUS 2 + 2

$1389.00$1450.00S 1896.00

DISK CONTROLLERS (A & T)

DJ-M26 M26 HARD DISK $720.00

DJ-M20 M20 HARD DISK S720.O0

DJ-M10 M10 HARD DISK $720.00

DJ-2208 DOUBLE DENSITY FLOPPY $349.00

DJ-1108 SINGLE DENSITY FLOPPY $219.00

STATIC MEMORY (A & T)

16K SUPERAM

16K MEMORY MASTER

24K MEMORY MASTER

32K SUPERAM

65K STATIC RAM

S248.00S284 00S378.00$450 00$870.00

'DECISION I BASIC UNIT $1342.00NOTE:

1 The disk subsystems include Digital Research CP/M2.2 and Microsoft Basic V5.2

I/O CONTROLLERS (A & T)

I.E.E.E. S-100 BUS (A&T)

SB-2411 SWITCHBOARD I/OSB-2411-4K 4K RAM OPTIONMB-3200 MULT I/O BOARD

$219.00$ 60.00$309 00

WB-0800 8 SLOT MOTHER BRD.WB-1200 12 SLOT MOTHER BRDWB-2000 20 SLOT MOTHER BRD.

2 If you own a MITS controller and disc drive, we havethe interface to run them with our new subsystems,$109.00 and a reformatter for your Pertec drives and software

$129.00 to translate your Mits files to your new operating

$173.00 system.

All shipments FOB Calabasas — 90 days warranty on all products

Prices. Terms, Specifications subject to change without notice.

66 October 1981 © BYTE Publications Inc

Circle 9 on inquiry card.

AnnoumThe Table Top ComputerThat Can't Be Topped.

The

5000 SXwith:

Capacity; 5.5 MB Winchester Plus TwoMini Floppies

If you know our Series 5000 table topcomputer line, you know that good thingscome in small packages.

Now, with the introduction of the 5000SX, big things come in small packages.

One integrated package can contain twodouble sided, double track density floppiesplus a 5.5 megabyte Winchester drive.

Speed: Load 20K in Less Than a Second

Not only does our high performanceWinchester subsystem include errordetection with automatic error correction,its extreme speed is comparable to thatof large main frame hard disk systems.

A 20K program loads in less than onesecond, about 10 to 12 times as fast asa floppy.

We invite comparison with our com-petitors' Winchester implementation soyou can see how a truly engineered solutionspeeds up your application programs.

Extras: You'll Be Glad You Have Them

The 5000 SX comes standard with lots ofextras, starting with a fully terminated S100mother board. Add to that 64K dynamicRAM modules, with parity, of course, andreceptacles for your CRT and Printer thatturn on with the main power switch.

Plus, convenient up front reset switch,incoming power line filter and much more.

Software:

Operating Systems: CPM, MPM,

TurboDOS

Languages: BASIC, FORTRAN, COBOL

Application Packages: FMS-80,

WORDSTAR, Accounting Plus, all

tailored to operate on the 5000 SX.

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There isn't room on this page to evenscratch the surface of the IMS Inter-national story.

However, our 2-year warranty is a deadgiveaway that we produce rugged, topquality, professional equipment. We dothings right the first time so they don'tcome back to us.

The truth is, we have fewer returnswithin our 2-year warranty period thanother manufacturers have within their90-day warranty periods.

For full details and the location of yournearoy IMS International dealer, call ustoday at (714) 978-6966. Or write:

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New Software from

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MicroCraft Systems, mc

Apple Software Development Tools

MicroCraft offers the Apple user a flexible set ofdevelopment tools. This includes a low-cost full screeneditor, the most powerful 6502 Macro Assembleravailable, and a compiled graphics language optimized forreal-time applications. Each package compliments anyApple system and together they offer unequaled powerand versatility.

RGL Real-time Graphics Language

Do real-time animation • Similar to 'C • Display, moveand rotate 3D objects • Compiles text files to 'BRUN'ablebinary object files. $75 / $25 Until 10/31/81

MacroLink Complete 6502 Assembler

Disk Assembler • Text to binary object • Standard 6502mnemonics • Recursive macros with up to 10 arguments

• Nestable conditional assembly • Links source or objectcode • Nestable file includes • Unlimited source file size

• Editor provided $125/$20

SuperEdit Full Screen Editor

Horizontal scrolling allows 80 columns • Uses standardtext files • Move cursor by character, line or page • Find,search and replace • Block move and copy • Use with RGLor MacroLink • 80 column video board versions alsoavailable. $75 /$20

DiskScreen Disk Utility

Displays a complete disk sector in hex and ASCII,using high-res screen • Edit sector by typing overdisplay $40/$10

Complete Assembler System [MacroLink, SuperEdit,DiskScreen] $200 / $40

Complete Graphics System [RGL, SuperEdit] $120 / $40

Systems available to utilize extra 16K or 32Kexpansion boards Please inquire

Note: All programs require a single disk drive and 48K.When ordering please specify configuration.

Circle 412 on Inquiry card.

Telephone (313) 996-1297

8086 Software

• VEDIT full screen editor for CP/M-86.

• Contact us for availability of VEDIT for SCP 86-D0S andIBM 8088 computer.

• CP/M-86 BIOS for popular S-100 disk controllers.

Source code $185

V-COM Disassembler

Finally a Z-80 disassembler for CP/M which produceseasy to read code, a cross reference table, and handlesINTEL and ZILOG mnemonics. V-COM is exceptionallyfast and produces a .ASM file directly from a .COM file.V-COM can accept a user-created file containingassignments of labels to 8 and 16 bit values. A second filecan specify the location of tables and ASCII strings. $80

FASTSCREEN CRT emulation andCommand Line Editor

Memory mapped displays offer over ten times thespeed of the fastest CRT terminal but are usually notsupported by application software. This is whereFASTSCREEN fits in. FASTSCREEN provides a fast andhighly compatible emulation of several popular CRTterminals for most memory mapped displays. It alsoprovides editing and re-entry of any line on the screen,paging, and includes interrupt driven keyboard routines.(FASTSCREEN is provided as source code on a CP/Mcompatible diskette and requires assembly languagemodifications for installation.) $85

PIICEON 24 x 80 S100 Video Board

The PIICEON V-100 is the heart of a high speedalternative to a CRT terminal. Being I/O mapped, it usesno memory space, yet runs at full processor speed.FASTSCREEN is the perfect software driver for theV-100. Fully assembled and tested by PIICEON, thecompany known by OEMs for reliability.

PIICEON with FASTSCREENPIICEON board only

$510

$475

Circle 413 on Inquiry card.

CompuView is proud to carry the MicroCraft Systems, Inc. quality software for the Apple II.

CompuView Products Inc.

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

Customizable

The Unique Difference that SetsVEDIT Apart in Full Screen Editors

Total user customizability is a predominate reason thatover a thousand users find VEDIT the easiest to use full screeneditor. It makes VEDIT the only editing package which allowsyou to determine your own keyboard layout and use the cursorand special function keys on any terminal having them. Andonly VEDIT fully supports all of the newly available terminals. Itmay come as a surprise to you, that with any other editor or wordprocessor, you will have to memorize obscure controlcharacters or multi-character sequences, while your terminal'sextra keys and editing functions go unused. The customizationextends to setting the default tab positions, scrolling methodsand much more. It's almost like designing your own editor foryour system, applications and preferences. And all of this iseasily done with the setup program which requires noprogramming knowledge or 'patches', but simply prompts youto press a key or enter a parameter.

Unequaled Hardware Support

The CRT version supports all terminals by allowing you toselect during setup which terminal VEDIT will run on. Featuressuch as line insert and delete, reverse scroll, status line andreverse video are used on 'smart' terminals. All screen sizes aresupported, including large ones such as the 60 X 80 format onthe Ann Arbor Ambassador terminal. Special function keys onterminals such as the Heath HI9, Televideo 920C and IBM3101, and keyboards producing 8 bit codes are all supported.The memory mapped version is extremely flexible and supportsbank select and hardware cursors such as on the SSM VB3.With this level of customizability and hardware support, you willfeel for the first time that the software was optimally designed foryour system.

Fully Compatible Replacement for Ed

Since VEDIT creates and edits standard text files of up toone diskette in length, it serves as a replacement for the CP/M

standard editor ED. Of course, you benefit from the fastest andeasiest to use 'What you see is what you get' type full screenediting available, fast disk access and an editor which takes uponly 12K of your valuable memory space. With VEDIT you willnever again need or want to use the slow and tedious ED.

Special Features

VEDIT is more than just a full screen editing replacementfor ED, it gives you many new editing capabilities, such as ascratchpad buffer for moving and rearranging sections of text,complete file handling on multiple drives and iteration macros.Amoung its special features you will find automatic indenting foruse with structured programming languages such as Pascaland PL/I, and other special facilities for Assembler and COBOL.A real time saver is the ability to insert a specified line range ofanother file anywhere in the text. Unlike most software, VEDITwill even tolerate your mistakes. For example, one key will'Undo' the changes you mistakenly made to a screen line, andthe disk write error recovery lets you delete files or insert anotherdisk should you run out of disk space.

Ordering

Many dealers carry VEDIT, or you may contact us for fastdelivery. Specify the CRT version, your video board ormicrocomputer, the 8080, Z80 or 8086 code version, and diskformat required.

VEDIT for 8080 or Z80: Disk and manual $ 130

VEDIT for CP/M-86: Disk and manual. (NEW) $ 185

Manual: Price refunded with software purchase $15

VISA or MASTERCARD Welcomed

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

• North Star * Cromemco * Heath H8/H89 * SuperBrain ' Apple II Softcard ' TRS-80 Model II & Model IMost 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 98 on inquiry card.

The Atari Tutorial

Part 2: Graphics Indirection

Chris Crawford

Atari Inc

1265 Borregas Ave

POB 427

Sunnyvale CA 94086

Indirection is a powerful concept incomputing, but a difficult one for thebeginning programmer to appreciate.In 6502 assembly language, there arethree levels of indirection in referringto numbers. The first and most directlevel is the immediate addressingmode, in which the number itself isdirectly stated:

LDA #$F4

The second level of indirection isreached when the program refers to amemory location that holds thenumber:

LDA $0602

The third and highest level of indirec-tion is attained when the programrefers to a pair of memory locationsthat together contain the address ofthe memory location holding thenumber. In the 6502, this indirectionis complicated by the addition of anindex:

LDA ($D0),Y

Indirection provides a greaterdegree of generality and power to theprogrammer. Instead of trucking outthe same old numbers every timesomething needs to be done, the pro-grammer can simply point to them.

By changing the pointer, the behaviorof the program can be changed. In-direction is an important capability.Graphics indirection is built intothe Atari Personal Computer systemin two ways: with color registers andcharacter sets. Programmers usingthis computer after programmingother systems often think in terms ofdirect colors. A color register is amore complex beast than a color. Acolor specifies a permanent value. Acolor register is indirect; it holds anycolor value. The difference betweenthe two is analogous to the differencebetween a box-end wrench and asocket wrench. The box-end wrenchcomes in one size only, but a socketwrench holds almost any size socket.A socket wrench is more flexible, buttakes a little more skill to use proper-ly. Similarly, a color register is moreflexible than a color, but takes moreskill to use effectively.

Color-Register Indirection

The Atari 400/800 has nine colorregisters; four are for player-missilegraphics and will be discussed in alater article in this series. The remain-ing five are not always used. Depend-ing on the graphics mode used, as fewas two registers, or as many as five,will show up on the screen. In BASICmode 0, only one and one-half

registers are used because the huevalue of the characters is ignored.Characters take the same hue asplayfield register 2, but take theirluminance from register 1. The colorregisters are in CTIA (one of the Ataricustom integrated circuits) at hexa-decimal addresses D016 throughD01A. They are "shadowed" (ie:copied) from certain RAM (randomaccess read/write memory) locationsin the Atari OS (operating system) in-to CTIA during the vertical blank in-terrupt of the video display. Table 1gives color-register shadow and hard-ware addresses.

For most purposes, the user con-trols the color registers by writing tothe shadow locations. There are onlytwo cases in which the programmerwrites directly to the CTIA addresses.The first and most common is thedisplay-list interrupt, which will becovered in a later article in this series.The second case arises when the userdisables the OS vertical-blank inter-rupt routines, which move theshadow values from the OS intoCTIA.

Colors are encoded in a colorregister by a simple formula. The up-per nybble gives the hue value, whichis identical to the second parameter ofthe BASIC SETCOLOR command.Table 9.3 of the Atari BASIC

70 October 1981 © BYTE Publications Inc

Circle 408 on inquiry card.

with

CRTFORM

CRTForm is a comprehensive packagefor creating interactive programs.

Good programming starts with clearspecifications. CRTForm saves time bygathering those specifications with a field-oriented editor. The editor can be used tomanipulate and modify input and systemfields, as well as to assert any of a com-plete group of input specifications.

A forms manager maintains the specifi-cations. It allows the analyst to create andmodify random access files of forms. Theform files contain the field attributes offorms as well as author, comment, andrevision information.

System analysts can easily producedocumentation by using CRTForm to printfield attributes and images of forms. Inaddition, a special Test mode allows theend user to test and verify the forms be-fore any code is produced.

CRTForm's code generator producesthe Pascal, BASIC, COBOL, FORTRAN,PL/1, Z-80, or Ada source text necessaryto interface to the runtime module.

The runtime module assures the userof consistent interaction with the com-

pleted application program. This reducestraining time, and eliminates the frustra-tion common in the use of many largeprograms.

The package automatically producesdocumentation and provides capabilitiesfor runtime enhancements. The program-mer can dynamically lock and unlock dis-plays, erase, skip, and reset fields. Inaddition, the system provides for redirec-tion of field access and enables the pro-grammer to send specialized error andcomment messages.

The system is terminal independent.This means that forms created for one ter-minal can be used on a terminal requiringdifferent control sequences. Functionkeys can be configured for specialapplications.

CRTForm is intended for use by sys-tem houses, program developers andOEMs. It is available under the CP'M,UCSD, Apple Pascal. RT-11. andRSX-11M operating systems.*

Statcom is a corporation specializing insoftware development tools and tech-niques. In addition to CRTForm. we offeran end user oriented report generationpackage. Please call or write for furtherinformation.

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Reference Manual lists hue values.The lower nybble in the color registergives the luminance value of the col-or. It is the same as the thirdparameter in the BASIC SETCOLORcommand. The lowest-order bit ofthis nybble is not significant. Thus,there are eight luminances for eachhue. This gives a total of 128 colorsfrom which to choose (eight lumi-nances times sixteen hues). In thisseries of articles, the term color de-notes a hue-luminance combination.

Once a color is encoded into a col-or register, it is mapped onto thescreen by referring to the colorregister that holds it. In map-displaymodes that support four colorregisters, the screen data specifywhich color register is to be mappedonto the screen. Since there are fourcolor registers, it takes only 2 bits to'encode one pixel. Thus, each screen-data byte holds data for four pixels.The value in each pair of bits specifieswhich color register provides the col-or for that pixel.

In color-text display modes

(BASIC'S graphics modes 1 and 2),the selection of color registers is madeby the top 2 bits of the charactercode. This leaves only 6 bits for defin-ing the character, which is why thesetwo modes have only 64 charactersavailable.

Color-register indirection gives theprogrammer four special capabilities.First, the programmer can choosefrom 128 different colors for displays.

Second, the programmer can ma-nipulate the color registers in real

time to produce pretty effects. Thesimplest version of this is demon-strated by the following BASIC line:

FOR 1 = 0 TO 254 STEP 2:POKE712,I:NEXT I

This line cycles the border colorthrough all possible colors. The effectis quite pleasing and certainly grabsattention. The fundamental techniquecan be extended in a variety of ways.A special variation of this is to create

ImageControlled

Hardware

OperatingSystem Shadow

Label

HexadecimalAddress

Label

HexadecimalAddress

player 0

COLPM0

D012

PCOLR0

2C0

player 1

COLPM1

D013

PCOLR1

2C1

player 2

COLPM2

D014

PCOLR2

2C2

player 3

COLPM3

D015

PCOLR3

2C3

playfield 0

COLPF0

D016

COLOR0

2C4

playfield 1

COLPF1

D017

COLOR1

2C5

playfield 2

COLPF2

D018

COLOR2

2C6

playfield 3

COLPF3

D019

COLOR3

2C7

background

COLBK

D01A

COLOR4

2C8

Table 1: Names and addresses of color registers used by the Atari 400/800.

"I have recently usedSpellguard and I canonly echo the eval-uations of a recentInfoworld review:excellent all the way."Mark GaretzInfoworld 25May 1981

"Spellguard is anexample of the newstandard—fully pro-fessional microcomputersoftware."Bill Burns

Infoworld 30 March1981

" . . . Spellguard wasgiven the manuscriptfrom my first book. Thisversion had beencorrected after several(human) proofreadersthoroughly reviewed it. Itherefore expected it tobe relatively error free.Not so. Spellguard was

EXPERTS AGREE

SPELLGUARD

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MOST POWERFUL

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SPELLING CHECKER

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able to discovernumerous typographicalerrors . . ."Allan MillerInterface AgeJune 1981

"This easy to use,operator-orientedprogram has saved me

countless hours ofproofreading, and fromthe embarrassment ofsubmitting a manuscriptwith typos. Unlike mostspelling test programs,Spellguard is fast . . ."Tony DowdenMicrocomputingMay 1981

InfoWorld

Software Report Card

^ELL

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System Requirements

• CP/M (1.4 or later)

• 32 K bytes of memory

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72 October 1981 © BYTE Publications Inc

Circle 178 on inquiry card.

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simple cyclic animation by drawing afigure in four colors, and then cyclingthe colors through the color registers,rather than redrawing the figure. Theprogram in listing 1 illustrates theidea.

The third application of color regis-ters is to logically key colors to situa-tions. For example, a paged-menusystem can be made more under-standable by changing the back-ground color or the border color foreach page in the menu. Perhaps thescreen could flash red when an illegalkey is pressed. The use of the colorcharacters available in BASICgraphics modes 1 and 2 can greatlyextend the impact of textual material.An account sum could be shown inred if the account is in the red, orblack if the account is in the black.Words or phrases of import can beemphasized in special colors. The useof colors in map modes (no text) canalso improve the utility of suchgraphics. A single graphics image (amonster, a boat, or whatever) couldbe presented in several different col-ors to represent several versions ofthe same thing. It costs a great deal ofRAM to store an image, but it costsvery little to change the color of anexisting image. For example, it ismuch easier to show three differentboats by presenting one boat shape inthree different colors than three dif-ferent boat shapes.

The fourth and most important ap-plication of color registers is usedwith display-list interrupts. A single

Listing 1: A short graphics programdemonstrating the illusion of movementby changing color-register assignments.

10

GRAPHICS 23

20

FOR X = 0 TO 39

30

FOR 1 = 0 TO 3

40

COLOR I

50

PLOT 4*X +1,0

60

DRAWTO 4*X +1,95

70

NEXT I

80

NEXTX

90

A = PEEK(712)

100

POKE 712,PEEK(710)

110

POKE710,PEEK(709)

120

POKE 709,PEEK(708)

130

POKE 708,A

140

GOTO 90

color register can be used to put up to128 colors onto a single screen. Thisimportant capability will be discussedin part 4 of this series.

Character Sets

Graphics indirection is also pro-vided through the redefinablecharacter set. A standard characterset is provided in ROM (read-onlymemory), but there is no reason whythis particular character set must beused. The user can create and displayany character set desired. There arethree steps necessary to use a rede-fined character set. First, the pro-grammer must define the characterset. This is the most time-consumingstep. Each character is displayed onthe screen on an 8 by 8 grid, which isencoded in memory as an 8-bytetable. Table 2 depicts the encoding ar-rangement.

A full character set has 128 charac-ters in it, each with a normal and in-verse video incarnation. Such acharacter set needs 1024 bytes ofspace and must start on a 1 K-byteboundary. Character sets for BASICmodes 1 and 2 have only 64 distinctcharacters. These require only 512bytes and must start on a Vz K-byteboundary. The first 8 bytes define thezeroth character, the next 8 bytesdefine the first character, and so on.Each group of 8 bytes is termed acharacter definition; the index thatdesignates such a group (FIRST char-acter, FIFTH character, etc) is calledthe character name. Obviously,defining a new character set is a bigjob. Fortunately, there are software

packages to make this job easier.

Once the character set is definedand placed into RAM, the second stepis to tell ANTIC (another custom in-tegrated circuit on the Atari 400/800)where it can find the character set.This is done by poking the pagenumber of the beginning of thecharacter table into hexadecimal loca-tion D409 (decimal 54281). The OSshadow location, the location nor-mally used, is called CHBAS andresides at hexadecimal 2F4 (decimal756). The third step in using charactersets is to print the character wantedonto the screen. This can be donedirectly from BASIC with simplePRINTs or by writing numbersdirectly into the screen memory.

A special capability of the systemnot supported in BASIC is the four-color, character-set option. BASICgraphics modes 1 and 2 support fivecolors, but each character in thesemodes is really a two-color character;each one has a foreground color and abackground color. The foregroundcolor can be any of four single colors,but only one color at a time can beshown within a single character. Thiscan be a serious hindrance whenusing character graphics.

There are two other text modesdesigned especially for charactergraphics, ANTIC modes 4 and 5.Each character in these modes is onlyfour pixels wide, but each pixel canhave four colors (counting back-ground). The characters are definedlike BASIC graphics mode 0 charac-ters, except that each pixel is twice aswide and has 2 bits assigned to it to

CHARACTERIMAGE

BINARYREPRESENTATION

HEXADECIMALREPRESENTATION

:

1

:<:

::

.

::x::

:

[y-

10 0

0 0

Table 2: Internal representation of a character in memory. One character needs 8bytes to represent it. Although the standard character set is in ROM, the pointer tothe beginning of the character set can be changed to point to other memory loca-tions, allowing the user to create a modified or completely new character set.

74 October 1981 © BYTE Publications Inc

^enjoy the problem-solvingpower of APL languageon your Apple computer

Solve engineering, scientific, or business problems easily-write finished applications software ina fraction of the time you'd take to write similar programs in BASIC, FORTRAN, or COBOL. . .and do it all with your Apple® right at your desk.

Test your language against APL

To compare APL/V80's clear concise code with the language you're now using to solve problems,take this short programming test. Here are three common problems, showing the APL/V80 solutionfor each. Program your best effort for each problem in the language you use now. Now compare thenumber of lines and keystrokes needed to achieve a solution in your language to the APL solution.Keep in mind the APL/V80 solution shown contains not only the computation commands, but alsoevery instruction needed to input required data, as well as all the commands to print out the results.

Problem 1:

Write a program to input a list of values (Listthen print all the values in list A in ascending order.

'A"), sort the list from lowest to highest values,

APL/V80 solution:

ALU+U1

Solution in your present language:

(Hint: Usually this takes two loops and 15 to20 statements.)Problem 2:

Write a program to input a list of values (List "X") and compute the standard deviation for thelist values.

APL/V80 solution: Solution in your present language:

((+/u-(+/;o*ff)*2)*ff"<-"i+pX-«-D)*.5 (Hint: This takes at least one loop and about

16 statements.)Problem 3:

Write a program which will compress adjacent spaces to a single space, with possible multipleoccurences, in a string of characters called TEXT.

APL/V80 solution: Solution in your present language:

(1 , ("l + DA-l + T*' '=TEXT)/TEXI-i-a ?

APL is the most concise, powerful programminglanguage available to develop computer solutionsfor scientific and business problems. Developedin the early 1960's, APL has been used to programlarge mainframe computers for years. Because APLhas so many functions and operators built in, onlyvery large computers could run APL programs until1977. In 1977, we at Vanguard changed that byintroducing APL/V80™ , a version of APL for Z80-based microcomputers. We've revised and extendedthis software now to run on your Apple*.

APL/V80™ for Apples is easy to learn, quickto write. It's a language proven easier to programin than BASIC, COBOL, FORTRAN, or even PASCAL.Because APL can apply a function to a whole arrayof data, when you store a list of values in an array,a single symbol in APL/V80 can do the work of anentire "DO" or "FOR" loop in other languages. Thisis programming power!Concise code saves thinking time

Compactness is part of the reason you can solveyour problems so much more quickly using APL/V80than by using other languages. With far fewer linesof code required, APL/V80 lets you developfunctionalsoftware, and debug it, in about one-fifth the timeyou'd need to program your problem in other lan-guages. With APL/V80, you can truly focus yourattention on problem-solving, rather than having toworry so much about the details of coding a programto compute your solution.Finished programs easier to understand

Because APL/V80 programs are so much shorterthan programs doing equivalent work in other lan-guages, APL/V80 programs are easier to read andunderstand, and they require less documentation.When you look at the APL/V80 solutions shown inthe box with our language comparison test, don'tlet the unusual symbols worry you. They may beunfamiliar to you now, but so were the commandsin your present language until you learned them. . .and APL is far easier to learn. APL/V80 uses thecommon mathematical practice of using a singlesymbol to represent a function, but there are somany functions built into APL there aren't enough

common symbols to represent them all. So APLuses additional symbols to represent those functionswhich go beyondthefamiliarmathematicaloperations.After you learn any language, you use as many ab-breviations as you can to save time. APL/V80 letsyou use "abbreviations" from your first efforts, savingmemory space both in your head and in your Apple.Solve your problems faster

Whether you're an engineer, scientist, educator,or businessman, now you can solve problems fasterthan ever using your Apple computer. With APL/V80from Vanguard Systems Corporation, you can searchfor solutions in a fraction the time you thoughtpiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiHiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiniiiiiiiiii

1 Contact your local Apple dealer for a demonstration of APL/V80 and get your copy today. If you don'tf have a local dealer, use this coupon to order direct from us now: Please rush the items ordered below.j I understand all items are normally in stock and available for immediate shipment:

□ Software PLUS Z-80 SoftCard PLUS RamCard

possible. APL/V80 makes your programs easier tounderstand, easier to write, easier to explain toothers, and easier to modify.A whole new world of convenience

APL/V80 is more than a language. . .it's a wholenew world of convenience for you and your Apple.Included with our APL interpreter are 6 new auxiliaryprocessors to make your life easier. The UtilityProcessor provides 6502 memory access and 6502processor calls so you can use routines stored inApple system ROMs and 6502-dependent peripherals.An Input Stack Processor lets you stack input com-mands for later execution. Our CommunicationsProcessor, when combined with an appropriate modem,lets your Apple communicate with another computer.The Graphics Processor gives you full access toApple's high resolution graphics. An APL File Pro-cessor gives you an indexed file system. Our CP/M**Input File Processor lets you read any CP/M anduseit with APL/V80.Hardware required

APL/V80 for the Apple requires the followinghardware for proper use: a 48k Apple II or AppleII+, one disk drive, a Z-80 SoftCard***, and eitherthe Language Card***, or RamCard***, or othercompatible 16k memory extension card.To learn more, act now

No matter how you use your Apple to solve prob-lems, APL/V80™ can help you solve them faster,with fewer errors. If you'd like to know more, sendus the coupon below. In the English language, wecan hardly begin to tell you in just one page all theways APL/V80 can help. Ah, if only we could writethis in APL/V80 itself. But send us the coupon,and we'll happily send you additional information(in English).

Note: Specifications subjecttochangewithoutnotice.

*Apple design, Apple II, Apple II+, & LanguageCard are trademarks of Apple Computer, Inc.**CP/M is a trademark of Digital Research***SoftCard and RamCard are trademarks of Microsoft

□ More information about APL/V80 for Apple

□ APL/V80™ User's Manual - Enclosed is $30.

□ Complete APL/V80 - Apple Software Package

Enclosed is $500. Please send me an end-user license, object code disk, documentationmanual, and special APL character generator.

□ Software PLUS RamCard ■ Enclosed is $675.D Software PLUS Z-80 SoftCard - Enclosed is

$850

□

□

Enclosed is $995

Complete Hardware ■ Software system - APL/

V80 ■ Apple Software PLUS Apple 11+ 48k

computer with APL character generation card

already installed PLUS Apple Disk Drive,

PLUS NEC 12" video screen PLUS SoftCard

PLUS RamCard. Enclosed is $3195.

As above with second Disk Drive - Enclosed

is $3695.

Enclosed is my check for $

OR Charge to; □ MasterCharge □ Visa

Ship to: Name

Address

City.

Card I

Signature.

exp. date

.State.

Phone._Zip.

VanquarcI Systems!

^^^ ' 6901 Blanco Road :

■ /\|ll\ San Antonio, Texas 78216

^^Vrl%L^« (512)340-1978:

iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii

Circle 382 on Inquiry card.

BYTE October 1981 75

Check the Osborne Books You

INTRODUCTORYBOOKS

Business SystemBuyer's Guide

by Adam Osborne and Steven Cook

Purchasing a computer for anybusiness is a complex process,but this book will help. Beforeyou buy any computer, read thisbook. You'll never make a betterinvestment. #47-0. $7.95 □

An Introduction toMicrocomputers

Volume 0:

The Beginner's Book

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Here's the book to start with ifyou know nothing about micro-computers but wish to learn. Pro-vides the concepts you'll need tounderstand this technology.

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An Introduction toMicrocomputers

Volume I: Basic Concepts

by Adam Osborne

The world's best selling textbookon microcomputers uses con-cepts that are common to allmicroprocessor systems. Showswhat a microcomputer can do,and how it does what it does.This edition is the most com-prehensive and up-to-date in-troduction to microprocessorsystems available anywhere.#34-9. $12.99 □

Running Wild-The NextIndustrial Revolution

by Adam Osborne

An insider's look at the micro-electronics revolution. Will thecoming years prove to be adream or a nightmare? RunningWild tells the story. #28-4, $3.95 d

GUIDES

Apple 11™ User's Guide

by Lon Poole, Martin McNiff andSteven Cook

Complements your Apple IIowners manual. Our guide willtell you more about your Apple IIor Apple II plus computer thanany other single source. Thisguide is a complete BASICprogramming tool. It covers allthe special features of the Applecomputer. #46-2, $15.00 □

PET/CBM™ PersonalComputer Guide

by Adam Osborne andCarroll Donahue

A step-by-step guide which takesyou from the "on" switch to as-sembly language subroutines foryour Commodore system. It's aBASIC tutorial and covers manyrecent CBM products.

#55-1, $15.00 □

tfc

PROGRAMMING. BOOKS

Science and EngineeringBASIC Programs

ed. by John Heilborn

An important collection of themost valuable programs forscientists and engineers. Easilyused on most popular micro-computers. #63-2, $15.99 D

Some Common BASICPrograms

by Lon Poole and Mary Borchers

76 well designed and brilliantlydocumented programs that solvea variety of problems in statistics,finance, and math.

Generalized BASICEdition #06-3, $14.99 □

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Practical BASIC Programs

Here are 40 useful and fully doc-umented programs designed torun on most microcomputers.Especially useful in small busi-ness and household applications.

(Generalized BASIC) #38-1, $15.99 D

OsborneCP/M™User Guide

by Thorn Hogan

The most complete and up-to-date CP/M book you can find. Itwill make your first use of CP/Measy. If you already own CP/M, itwill help you modify your system.

#44-6, $12.99 D

CBASIC "Users Guide

by Adam Osborne, Gordon Eubanksand Martin McNiff

Co-authored by Gordon Eu-banks, the creator of CBASIC,this is more than a self-teachingtextbook, it is the definitive ref-erence of the CBASIC language.

#61-6, $15.00 D

Want $T

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by Lon Poole and co-authors

Osborne's three business sys-tems are renowned for excel-lence in design and documenta-tion. Our books explain in de-tail how to use the programs.They contain complete programlistings, supporting technicaldocumentation, and specific in-formation on changing andinstalling the programs.

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LANGUAGE

PROGRAM

SERIES

by Lance Leventhal and co-authors

You needn't know anythingabout assembly language to usethese books. Each one is astraightforward, self-teachingtextbook that is both precise andeasy to understand.

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by Russell Rector and George Alexy

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. INTERFACE

Interfacing to S-100 (IEEE696) Microcomputers

by Sol Libes and Mark Garetz

Describes the S-100 Bus withunmatched precision. Coversmechanical and electrical design,logical and electrical relation-ships, bus interconnections, andmuch more. #37-3. $15.00 □

Circle 285 on inquiry card.

PET and the IEEE 488 Bus(GPIB)

by E. Fisher and C.W. Jensen

Provides chapters on all aspectsof the General Purpose InterfaceBus. Includes lines, signals,specifications, and much more.

#31-4. $15.99 □

Microprocessors forMeasurement and Control

by D.M. Auslander and P. SaguesLearn to design mechanical andprocess equipment using micro-processor based "real-time" com-puter systems. This book allowsreaders (even those unfamiliarwith machine or assembly lan-guage) to initiate projects.

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MICRO-ELECTRONICREFERENCES

Osborne 4 & 8 Bit

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by Adam Osborne and Gerry KaneThe one source for complete,objective and accurate informa-

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#43-8, $19.95 □

An Introduction toMicrocomputers:Volume 3 - Some RealSupport Devices

by Gerry Kane and Adam Osborne

Available with or without 3-ringbinder or updates. Each deviceis described in detail, includingan analysis of the best uses forthat device. Book - #18-7, $15.00 a

Binder - #19-5. $6.99 □Six Updates - #98. $25.00 D

HANDBOOKS

68000 MicroprocessorHandbook

by Gerry Kane

This handbook offers more in-formation about the 68000 thanthe manufacturer's data sheets.

#41-1, $6.99 D

CRT Controller Handbook

by Gerry Kane

Describes five devices in thesame thorough detail you'll findin Volume 3. Contains 13 tablesand 149 separate illustrations.

#45-4, $6.99 D

8089 I/O ProcessorHandbook

by Adam Osborne

A complete presentation of the

8089. The 8289 Bus Arbiter is

also described with the same

careful attention to design and

application.

#39-X. $6.99 □

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You can save buying wholesalewith our buying service. As youragent we will buy computerequipment on the wholesalemarket for you. Our fee is onefourth of what we save you offlist price. Access to over 500manufacturers. Minimum fee of$100. Call for present wholesalemarket conditions.

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specify the color register used. UnlikeANTIC modes 6 and 7 (BASIC modes1 and 2), color-register selection is notmade by the character-name byte,but instead by the defined characterset. Each byte in the character table isbroken into four bit pairs, each ofwhich selects the color for a pixel.(This is why there are only fourhorizontal pixels per character.) Thehighest bit (D7) of the character-namebyte modifies the color register used.Color-register selection is made ac-cording to table 3.

Using these text modes, multicol-ored graphics characters can be putonto the screen.

Another interesting ANTIC char-acter mode is the lowercase-descenders mode (ANTIC mode 3).This mode displays ten scan lines permode line, but since characters use

only 8 bytes vertically, the lower twoscan lines are normally left empty. Ifa character in the last quarter of thecharacter set is displayed, the top twoscan lines of the character will be leftempty. The data that should havebeen displayed there will be shown onthe bottom two lines (see figure 1)-This allows the user to create lower-case characters with descenders.

Modified Character Sets

Many interesting and useful ap-plication possibilities spring fromcharacter-set indirection. The ob-vious application is the modifiedfont. A different font can give a pro-gram a unique appearance. It is possi-ble to have Greek, Cyrillic, or otherspecial character sets. Going one stepfurther, graphics fonts can be created.The Energy Czar computer program

Bit Pair InCharacterDefinition

ColorRegister Selected

D7 = 0 D7 = 1

00011011

Table 3: Use of color4 and 5. See the text

registers infor details.

COLBAK COLBAKPF0 PF0PF1 PF1PF2 PF3

character definition during ANTIC graphics modes

Photo 1: A bar chart made using character graphics. Even though each character is eightpixels wide, the horizontal bars can be any number of pixels wide by using redefinedcharacters representing bars of varying width.

Circle 379 on inquiry card. >

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JF

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USER-DEFINEDFORMS AND FILES

With OPTIMUM, implementing anapplication is simple. The user definesscreen forms to fit the data and describeshow the data is to be stored. Once this iscomplete, data entry may begin. Inputediting, validation and cross-referencingduring data entry extend OPTIMUM'Srange. If the need exists, OPTIMUM canhandle complex or multiple screen formsfor the same file. Screen forms may bemodified and expanded as needed.

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Photo 2: Tu>o uiews o/ a war-game map made totally from character graphics. Themap is several times larger than the video display, and a player can use a joystick toview different parts of the map. Even though character-sized graphics are used, thescrolling appears to be smooth due to some advanced Atari display techniques.

(sold by Atari) uses a redefinedcharacter set for bar graphs. Acharacter occupies eight pixels. Thismeans that bar charts implementedwith standard characters have aresolution of eight pixels, a ratherpoor resolution. Energy Czar uses aspecial character set in which some ofthe less useful text symbols (amper-sands, pound signs, etc) have beenreplaced with special bar-chartcharacters. One character is a one-pixel bar, another is a two-pixel bar,and so on to the full eight-pixel bar.The program can thus draw detailed

80 October 1981 © BYTE Publications Inc

bar charts with resolution of a singlepixel. Photo 1 shows a typical displayfrom this program. The mix of textwith map graphics is only apparent;the entire display is constructed withcharacters.

In many applications, charactersets can be created that show specialimages. For example, by defining aterrain graphics character set withriver characters, forest characters,mountain characters, and so forth, itis possible to make a terrain map ofany country. With imagination, a ter-rain map of a different planet can just

<0U

0_ ^

00

Circle 254 on inquiry card.

If what you needis more of you...

Pascal/MT+®

With our exclusive SpeedProgramming ™ Package

Do you ever wish that you had more good people like yourself when you really have toproduce? Pascal/MT+" and the SpeedProgramming '" Package makes you feel like you havean army of workers who know just what lo do. With oil of the tools we provide you forediting, checking, compiling, debugging and documenting your programs you are able loproduce working programs in an amazingly short time, With Pascal/MT+<" andSpeedProgramming *" you will never feel short-handed again!

Pascal/MT+» is a total programming system including our native machine code compiler,linker, Pascal-level debugger, disassembler, run-time subroutine library and the exclusiveSpeedProgramming '" Package. Used by thousands of companies worldwide, our customershave told us that the Pascal/MT+2 system, with its built-in mini-assembler and languageextensions, all but eliminates the need for any assembly language programming. Theefficient machine code produced by the ISO Standard Pascal/MT+^ compiler combinedwith our extensions to the Pascal language for bit/byte manipulation. I/O port handling,business arithmetic, hardware floating point support along with our exclusive interruptprocedures allow construction of programs ranging from ROM based controllers andoperating systems to extensive data base applications.The Pascal/MT+ System:Compiler: Generates ROMable Native Code

• Complete ISO Standard (superset of Jensen & Wirth)

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• Modular Compilation

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The SpeedProgramming Package is an integrated set of tools which allows you to createPascal/MT+1' programs, check them for correct syntax and undefined identifiers, formatthem to display flow of control, and do this all within the editing environment before youever invoke the compiler. Programmers like SpeedProgramming because it frees them fromthe lime consuming chore of repeated compilations to correct simple syntactic and typingerrors. Managers find that SpeedProgramming improves productivity, thereby reducingdevelopment costs. SpeedProgramming combined with our field tested Pascal/MT+package gives you a comfortable, powerful .interactive programming environment in whichto create your professional quality software. Your products demand production qualitytools. Order Pascal/MT+* with SpeedProgramming today!Screen Editor

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• 8080/8085/Z80 Price $47556K Mm CP/M-80

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Coming soon;b8000 Price (to be announced)

Initially cross compilerResident compiler lo follow

Available on 8" (3740) single density Contact distributors for other formats.OEM INQUIRIES INVITED

/MT Micro SYSTEMS\

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Circle 255 on inquiry card.

Circle 266 on inquiry card.

If you have anythingto do with smallcomputers, youshould be readingthe Carl Helmers

persons,computer

LETTER

every month!

You won't want to miss a single issue ofthe new Personal Computer Letter...a monthly publication of comprehen-sive studies on issues affecting design,implementation, and applications ofsmall computer systems. The PersonalComputer Letter is a journal compiledand edited by Carl Helmers, co-founderand first editor of Byte Magazine Hereis valuable information in professionallyprepared format about small com-puters, software, peripherals, trends inthe industry, and new ideas. We acceptno advertising and the informationprovided is available nowhere else.Written for executives, decision-makers,market strategists, product designersand authors in the small computer field,each 12 to 16-page issue containsanalysis and design studies by manyof the personal computer industry'sforemost experts. For example, thecurrent issue covers: A Voice In TheWilderness: Some first reactions toexperiments with voice-aided inter-active programs.

Subscribe today. Mail the coupon withyour check for $200 for the next 12monthly issues. Sample issues at$25 per copy, applicable to a fullyear's subscription.

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□ Enclosed is my $200 check ormoney order for the next 12 issuesof the Personal Computer Letter.

□ Enclosed is my $25 check or moneyorder for a sample issue, applicableto subscription price.

NAME !

ADDRESS

CITY

STATE ZIP

82 October 1981 © BYTE Publications Inc

IIII

as easily be done. When doing this, itis best to define five to eightcharacters for each terrain type. Eachvariation of a single type should bepositioned slightly differently in thecharacter pixel. By mixing the dif-ferent characters together, it is possi-ble to avoid the monotonous lookcharacteristic of primitive charactergraphics. Most people won't realizethat the resulting map uses charactergraphics until they study the mapclosely. Photo 2 shows two views of aterrain map created with character-set graphics.

You could create an electronicscharacter set with transistor charac-ters, diode characters, wire charac-ters, and so forth to produce an elec-tronics schematics program. Or youcould create an architecturalcharacter set with doorway charac-ters, wall characters, corner charac-ters, and so on to make an architec-tural blueprint program.

Characters can be turned upsidedown by POKEing a 4 into decimallocation 755. One possible applica-

tion of this feature might be fordisplaying playing cards (as in ablackjack game). The upper half ofthe card can be shown right-side up;with a display-list interrupt, thecharacters can be turned upside downfor the lower half of the card. Thisfeature might also be useful indisplaying images with mirror reflec-tions (reflection pools, lakes, etc).

Even more exciting possibilitiesspring to mind when it is realized thatit is practical to change character setswhile the program is running. Acharacter set costs either 512 bytes or1024 bytes; in either case, it is inex-pensive to keep multiple charactersets in memory and flip between themduring program execution. There arethree time regimes for such character-set multiplexing; human slow (morethan 1 second), human fast (1/60 sec-ond to 1 second), and machine fast(faster than 1/60 second).

Human-slow character-set multi-plexing is useful for change of scenerywork. For example, a space-travelprogram might use one graphics

I

1

v.v

a

CHARACTER

AS DISPLAYED

IN ANTIC

MODE 3

THESE TWO ROWSARE KEPT BLANK

THESE SIX ROWS ARECOPIED FROM THEBOTTOM SIX ROWS OFTHE STORED IMAGE

THESE TWO ROWS ARECOPIED FROM THE TOPTWO ROWS OF THESTORED IMAGE

CHARACTERIN FIRST THREE-QUARTERSOF CHARACTER SET

CHARACTER

IN LAST QUARTER

OF CHARACTER SET

Figure 1: Lowercase descenders in ANTIC mode 3. Using the method shown here, theAtari 400/800 can display characters in an 8 by 10 matrix, even though their internalrepresentation is an 8 by 8 matrix.

SuperSoffc Optimizing

The SuperSoft "C" compilersupports'most of version 7 Unixstandard "C". Several special andwidely desired features aresupported, including:

1 Macro expansions via the#define statement.

- Include files using the #inc-lude statement.Inline assembly code issupported with the #asm andiendasm.

1 The object code may be

ROMed.

• Programs may be ORGed forany location.

•> Completely dynamic memoryallocation is supported, bothby the compiler and in userprograms. (That is, thefunctions 'alloc' and 'free' areprovided with the compiler.)

SuperSoft "C" is a two passcompiler. The first pass of thecompiler produces an intermediatecode (U-code, for Universal code).Pass two contains both thetranslator and the optimizer. Theintermediate code is optimized andassembly code is output to file.

The optimizer typically results in40% code reduction. This meansthat compiled object code will runnearly as fast as that which waswritten in assembler.

An important feature of the compileris that aseembly code is produced.This means that "handoptimization" of critical sections ispossible. Also, the inline coderallows easy insertion of assemblylanguage routines.

With the compiler comes thecomplete source code to the I/Olibraries. These libraries are equal toor better than any that exist for the8080/Z80 computer system.Functions included:

open close read writeseek tell fopen createputc getc flush

The Seek command supportsabsolute, relative from front, andrelative from ervd of file. Fopenincludes fcreat. Also included withthe compiler are numerous sampleprograms and a complete library ofuseful functions.

forCP/M

Compile time options Include listingfile, console output, syntaxchecking and others.

Requires: 48K CP/M, (more recommended)"C" compiler: $200.00

Manual only: $ 20.00

Z8000 cross-compiler: : kvuv

(CP/M to Z8000 code, requires Z8000assembler)Source code forin-house use only: $5,000.00

CP/M formats: 8"'soft sectored, 5" Nor-ttistar, 5" Micropohs Mod II, Vector MZ,Superbrain DD/QD.Apple II +

All Orders and General.Information:

SUPERSOFT ASSOCIATESP.O. BOX 1628 f

CHAMPAIGN, IL 61820(217)359-2112Technical Hot Line: (217)359-2691

.(answered only when technicianis available)

•CP/M registered trademark Digital Research■Unix registered trademark Bell Laboratories

■

character set for one planet, anotherset for space, and a third set foranother planet. As the travelerchanges locations, the programchanges the character set to give ex-otic new scenery. An adventure-typeprogram might change character setsas the player changes locales.

Human-fast character-set multi-plexing is primarily of value foranimation. This can be done in twoways: changing characters within asingle character set, and changingwhole character sets. The Space In-vaders game on the Atari 400/800uses the former technique. The in-vaders are actually characters. Byrapidly changing the characters, theprogrammer was able to animatethem. This was easy because there areonly six different monsters, each withfour different incarnations. High-speed cyclic animation of an entirescreen is possible by setting up anumber of character sets, drawing thescreen image, and then cyclingthrough the character sets. If eachcharacter has a slightly different in-

carnation in each of the charactersets, that character will go through ananimated sequence as the charactersets are changed. In this way, a screenfull of objects could be made tocyclically move with a simple loop.Once the character-set data are inplace and the screen has been drawn,the code to animate the screen wouldbe this simple:

1000 FOR 1 = 1 TO 10

1010 POKE 756,CHARBASE(I)

1020 NEXT I

1030 GOTO 1000

Computer-fast character-set ani-mation is used to put multiple charac-ter sets onto a single screen. Thismakes use of the display-list interruptcapability of the computer. This topicwill be addressed further in a later ar-ticle in this series.

The use of character sets forgraphics and animation has many ad-vantages and some limitations. Thebiggest advantage is that it costs littleRAM to produce detailed displays. A

graphics display using BASIC mode 2characters (such as the ones in photo2) can give as much detail and onemore color than a BASIC mode 7display. Yet, the character image willcost 200 bytes, while the map imagewill cost 4000 bytes. The RAM costfor multiple character sets is only 512bytes per set, so it is inexpensive tohave multiple character sets. Screenmanipulations with character graph-ics are much faster because you haveless data to manipulate. However,character graphics are not as flexibleas map graphics. You cannot putanything you want anywhere on thescreen. This limitation precludes theuse of character graphics in some ap-plications. However, many graphicsapplications remain for which theprogram need display only a limitednumber of predefined shapes in fixedlocations. In these cases, charactergraphics provide great utility. ■

This article appears in slightly different formin De Re Atari, published by Atari, Inc, and isreproduced with its express permission.

3 ALTERNATIVE INTERFACESFORTHETRS-80

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Call 1-800-645-3479. in N.Y. 1-516-374-6793or write: The MicroMint Inc.

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84 October 1981 © BYTE Publications Inc

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Software Review

Atari's Telelink I

Glen Flint

14219 Pierce PI #41

Omaha NE 68144

Telelink I is a program cartridge for the Atari 400 or800 personal-computer system that lets you access databases, electronic mail, and other services offered by in-formation utilities such as The Source and CompuServe.You must have the Atari 850 interface module and anAtari 830 modem, or the equivalent, to use Telelink I.One of Atari's printers, Atari 820, Atari 822, or Atari825, may be used.

Telelink I comes with a well-prepared five-pagemanual explaining the use of the cartridge. Following ageneral introduction, the manual explains how to hookup the modem, telephone, and printers. It also describessome of the options for controlling the printers, the widthof the screen, and the word or the character mode (whichwill be explained later). There are lists of what will betransmitted by each of the keys on the keyboard. Some

Name

Language

Telelink I

6502 assembly language

Type

Computer

Communications utility

Atari 400 or 800 computer

with an Atari 850 interface

Manufacturer

module and an Atari 830

Atari Inc

modem (or equivalent)

1346 Bordeaux Dr

Sunnyvale CA 94086

Documentation

(800) 538-8547; in California

5 pages, 8V2 by 11 inches

(800) 672-1404

Audience

Price

Individuals wishing to use

$19.95

information utilities and

timesharing networks

Format

Computer program cartridge

(read-only memory)

special control-character combinations send ASCII(American Standard Code for Information Interchange)characters not available on the Atari 400 and 800 key-boards. (For example, a Control-[ sends a {.) A list of de-finitions of several data-communications terms is also in-cluded. Finally, the manual lists the ASCII character setwith the decimal and hexadecimal values of each charac-ter. The meanings of the ASCII control characters arealso given.

An offer to sign up with CompuServe and receive onehour of free time on Micronet is included when you buyTelelink I. Micronet has several services that may beof interest to the Atari user: one is the monthly Atarinewsletter. Another service is a CB (citizen's band) radiosimulator. Users can enter the CB simulator and talk withcomputer users across the country.

Control Features

Pressing Control-8 changes the width of the screenfrom 38 characters to 40 characters. Control-0 toggles be-tween word mode and character mode. The charactermode splits words at the edge of the screen; the wordmode, which moves a word to the next line rather thansplitting it, improves the readability of the text on thescreen. This is also known as word wrap.

Atari's printers can be used with Telelink I to providehard copy of a terminal session. Telelink I reserves a1.5 K-byte buffer for the printer. This buffer can beprinted automatically or under direct user control withthe Select key. In the automatic mode, 1 K bytes of dataare collected in the buffer, then an ASCII XOFF is trans-mitted to the sender. (XOFF is an ASCII control charactermeaning "stop sending data.") At this point, Telelink Istops looking for data from the modem and begins print-ing the information stored in the buffer. When the buffer

86 October 1981 © BYTE Publications Inc

>

c

"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 onewe make lightly.

"After all, being the only product on the market witha Vector 3 terminal, a 5%" floppy, and a 5J4" Winchesterrigid disk drive that provides 5 megabytes of storageis quite a responsibility. It used to take 20 floppies to giveyou that kind of capacity.

"Our powers don't stop there, however. Each 3005 alsocomes with a 32-bit error-correcting code —the first timesophisticated IBM-style technology has been availableon a small business system.This lets us detect and correcterrors, and almost completely eliminates data loss ondisks due to dirt, wear, or damage.

"All this makes us pretty awesome, all right. But there'smore. When coupled with Vector's MEMORITE III andEXECUPLAN software packages, we give you a 30,000word dictionary, the ability to create your own phraselibrary, a teaching manual right on the screen, pass wordsecurity, plus a host of other word processing capabili-ties as well as financial planning, forecasting andbasic accounting.

"And we're reliable. Our powers won't diminish, Durabili-ties won't fade, and dedication to mankind won't weaken.

"For more information and your nearest dealer, callVector 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 havethe chance to do business together in the future!'

VECTOR GRAPHIC INC.COMPUTERS FOR THE ADVANCEMENT OF SOCIETY.

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Circle 17 on inquiry card.

Get on the right track! Jointhousands of professionals, insti-tutions and businesses who relyon Altos computer systems. Callour toll free number or writetoday for the Altos sales andservice depot nearest you.

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© 1981 Altos Computer Systems

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is empty, Telelink I transmits an XON to the sender.(XON is an ASCII control character meaning "start send-ing data.") Once the buffer has been filled, this process isrepeated. All this is automatic and is handy for copyinginformation to the printer when no user interaction is re-quired.

In the nonautomatic mode, data is received until 1 Kbytes of data have been stored in the buffer. At thispoint, the keyboard begins to make a clicking noise, sig-naling that the buffer is nearly full. The user must dowhatever is required by the communications protocolcurrently in use to stop the transmission of data. (Due tothe serial data transmission on the Atari 400 and 800 pe-ripheral bus, the Atari 850 interface module cannotshare the bus with any other peripheral device, includingthe printer.) To print data, the Atari 850 must not be at-tempting to transmit or receive data. Telelink I causes theAtari 850 interface to cease monitoring the communica-tion link for incoming data while printing the contents ofthe buffer. If the transfer of data is not stopped, the datathat was received during printing will be lost.

Once the transfer has been stopped, the Select key maybe pressed, and the contents of the buffer will be printed.When the contents of the buffer have been printed, theuser should send the character(s) required to resumetransmission of data. Another buffer will be filled andcan be printed by repeating the procedure.

The options provide means to configure Telelink I toyour needs. Pressing System Reset will set all of the op-tions back to their default values. Although the auto-matic printer feature would be convenient, the two net-works I tried, CompuServe (through Tymnet) and HDRSystems Inc (in Omaha, Nebraska), didn't respond to theXON and XOFF control characters. The nonautomaticmode will have to be used in cases where the host com-puter does not recognize XON and XOFF.

When an option is changed, the change is printed onthe screen. Perhaps it would have been more helpful toreserve one line of the screen to show all the status infor-mation continuously. This would make it easy to deter-mine exactly what mode the printer is in at any time.Another helpful feature Atari could have added is theability to select local echo of keyboard input, rather thandepending on the host computer to send back each char-acter it receives.

Conclusions

• The Telelink I cartridge provides an easy way to turnyour Atari 400 or 800 computer into a terminal for dial-ing into information utilities and timesharing networkssuch as The Source and CompuServe.

• The printer-control features make the cartridgevaluable for an Atari system with a printer. The ability toget a hard copy of a terminal session is a definite plus.

• For an Atari system without a printer, the decision maybe harder. A simple program to emulate a terminal usingGET and PUT (in Atari BASIC) was given in the Febru-ary 1981 Compute. The word mode is a nice feature andprobably makes the cartridge worth the extra expense. ■

90

October 1981 © BYTE Publications Inc

Circle 264 on inquiry card.

Circle 61 on inquiry card.

■■■.;.

Reliability, price, and a performance kickerthat leaves other S-bit systems far behind: Realtime hardware vectored interrupts and the OASIS

:.■■'.' ■ ■ '■ ■ . ■ . - ■ ... : ' ■.■■■■ :■.:■,:

multi-user OS for an economical system thatrivals 16-bit performance. CP/M is includedoppy disk and hard disk subsystems, termprinters, board-level

Bi it -;. e bra

Local-Area Networks

Possibilities for Personal Computers

Dr Harry J SaalNestar Systems Inc2585 E Bayshore RdPalo Alto CA 94303

Today's technical press is filledwith announcements of "local-areanetwork" products and "personalcomputers." New technologies frombillion-dollar corporations are beingrivaled by products from small firms,in a field no more than a few yearsold. This article provides an overviewof local-area networks and how theyrelate to personal computers.

Defining local-area network isevery bit as difficult as defining per-sonal computer. Features, prices, andtechnology are distributed across abroad spectrum. Thus, we will try todescribe the distinguishing character-istics of a local-area network—howto know one when you see one—anddiscuss some related system designsthat are not local networks, but ad-dress many of the same requirements.

Personal Computersand the Group

The revolution in computersystems began with dramatic ad-vances in silicon technology thatgreatly reduced the cost of the "com-puting" part of a computer system.Before this, CPU (central processingunit) cycles were a valuable andscarce resource; whole industriesgrew up developing hardware andsoftware techniques to squeeze out

the last bits of efficiency from bigmainframes. Learned papers on howto salvage another two percent ofprocessing time dominated computerconferences. People gathered in com-puter centers (hospital-like en-vironments with air conditioning,raised white floors, and observationgalleries). Then, suddenly, all thatchanged.

The cost of the CPU is no longerthe dominant concern. Instead, elec-tromechanical devices such as disks,printers, terminals, and cablesgenerally cost more than the entirecentral processor. As the prices ofthese peripheral components drop,the time people spend using thesystems becomes more important.We need rapid access to information;we need to review alternatives "on-line" to make decisions quickly. Ourcomputer systems must respond toour needs and schedules, not theother way around.

The personal computer is dedicatedto providing this environment. It isready for work when we want to useit. It is typically dedicated to one per-son (or task) and not shared withother people. Although timesharingsystems attempted to give the user theillusion of a dedicated computer, theyfailed because inevitably the load

presented by numerous users slowedthem down. A personal computer, onthe other hand, responds equally wellat any time of day. We no longerneed to worry about the "wastedcycles" if we simply leave it on ourdesks just blinking its cursor. Thehallmark of the personal computer isthis "one person, one computer"approach.

While having to share a centralprocessor may not be justified formany of today's computing needs,information sharing is as importantas ever. Once two or more peoplebegin to work cooperatively, theyneed to communicate and exchangeinformation, whether the impetus bethe joint development of a large pro-gram, several people checking on in-formation in a common data base, orthe implementation of an electronicmail system.

Sharing of larger and more reliableperipheral devices is equally impor-tant in all but the smallest computerapplications. We can't all have ourown letter-quality printer in ouroffice, though we may need access toone. Large libraries of programs orextensive data bases require largerdisks than those normally connectedto personal computers. Their cost(and reliability) is much higher than

92 October 1981 © BYTE Publications Inc

SuperSoft's

Gallery of CP/M Masterworks

Programming Languages"C"

FORTH

FORTRAN IV

RATFOR

BASIC

'TINY' PASCAL

Disk/Manual Only

$200/20

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$ 85/10

System Maintenance

Diagnostics IIDiagnostics 1DISK DOCTOR

$100/15$ 75/15$100/15

Utilities

Utility Pack #1Utility Pack #2

$ 60/NA$ 60/NA

Text Processing

TFS

Super-M-List

$ 85/15$ 75/10

Software Security

Encode/Decode IIEncode/Decode I

$100/20$ 50/20

Intercommunications

TERMTERM II

$150/15$200/15

Entertainment

ANALIZANEMESISDungeon Master(For use with Nemesis)

$ 35/NA$ 40/NA$ 35/NA

Miscellaneous

Z8000 Cross-Assembler"C" Cross-Compiler(Z8000 Target)

$500/25$500/25

s

******* tnfiitlltiit * * * * A ^

TERM

A Complete Networking/Intercommunications Package

TERM allows the CP/M user to communicate withother CP/M based systems or with remote timesharingcomputers. TERM supports file transfers between bothtimesharing systems and between CP/M systems.

TERM equals or exceeds comparable programs inpower and flexibility, but costs less, delivers more andsource code is provided on discette!

With TERM you can send and receive ASCII, HEXand COM files. You also have a conversational mode,and a timesharing terminal emulator. Below is a partiallist of features:

• Engage/disengage printer • terminal emulator

• auto error checking with re-try

• conversational mode

• send files • receive files

requires 32K CP/M and a minimal knowledge of assembly languageprogramming.

TERM is supplied with source and user manual: $150.00Manual only: $15.00

VWWJ

TERM

f'TTTT'efl

Many programs include SuperSoft's online "HELP" system!

S3

fig

M

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the stripped-down "consumer" var-iety offered by most personal com-puters.

Multiuser Systems

Personal computer networkspreserve the independence of eachcomputer work station while offeringthe possibility of sharing informationand devices among the individuals onthe network. Networks are useful inalmost all situations where severalpeople need to work together andshare information, but still want theattractive features of the dedicatedpersonal computer.

Of course, we can satisfy themultiuser requirements in a moretraditional way, too. A number ofcompanies offer shared multiusersystems based on a single micropro-cessor. Digital Research's MP/Msystem permits up to sixteen users toshare a common microprocessor andits peripherals. MP/M is a derivativeof the popular CP/M operatingsystem that permits applications writ-ten for that environment to functionfor multiple users. Onyx's C8000 is amultiuser system based on the ZilogZ8000 microprocessor running theWestern Electric UNIX operatingsystem.

Multiuser systems are fundamen-tally similar to timesharing systems ofthe past. Users may be happy withthe performance as long as thedemands on the single processor arelow, but they share one of the greatweaknesses of central computer sys-tems in that if the processor shouldfail, everyone loses his work and hasto wait until the system is repaired orrestarted. And because of the sta-tistical nature of the sharing of theprocessor, things we take for grantedin personal computers, such as real-time graphics and instantaneousresponse to keystrokes, are sacrificed.

Networks, Networks, Networks

Until five years ago, a computer-communications network generallymeant a connection of a large numberof terminals, geographically dis-tributed throughout a company oracross the country, to one or morecentral computers.

Anyone using The Source or Com-

puServe (Micronet) uses such a net-work. The terminal is connected bytelephone to a nearby communica-tions processor, which takes the fairlylow-speed information (30 to 120characters per second) going to orfrom your home and merges it withthe data of other local users. Thesecommunications processors are con-nected together by much higher speedlines from city to city. The data areput into groups, called packets, withrouting information and error-detect-ing fields appended, and sent fromsite to site until the packets arrive at aprocessor connected to a large time-sharing system. (Western Union'sTelex and TWX services are other ex-amples of international low-speednetworks.) These networks processinformation at speeds appropriate forhumans typing or reading data from ascreen. Loading a 16 K-byte programor operating system takes over nineminutes at 300 bps (bits per second);the same load would take under onesecond from a local floppy disk.

Some networks are used to connectcomputers rather than terminals.They run at much higher speeds andtransmit large files, documents, andelectronic mail between systems. Buteven these nets don't have the band-width required to allow modernstorage devices to operate at fullspeed, and are not acceptable for theinteractive transmission of programand data files in real time.

Device Sharing

There are a number of systems onthe market that permit each user tohave his own dedicated computer andshare disks or printers, but which arenot truly computer networks. Severalrecent products permit numerous in-dependent microprocessor boardsand separate memory to be installedin one chassis. One of these boards isgenerally reserved for shared accessto one central disk subsystem orprinter. A terminal is attached to eachprocessor, so each user on the systemactually has a dedicated micro-processor.

Such a system is quite attractive,but certain inherent disadvantagesstill remain. The chassis is large,needs a big power supply and large

94 October 1981 © BYTE Publications Inc

Circle 262 on inquiry card.

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This high quality professional computer monitorprovides sharp, clear display of up to 80 characters by25 lines of text, making it ideal for word processing aswell as standard business applications.

Lightweight industrial grade construction givesmaximum portability with reliable operation.

Color monitor also available for Apple;"' Atari5 andother popular computers. See your authorized NECAmerica Dealer.

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cooling capacity, and if any modulefails, the entire system, generally, isdown. There is no way to add morestations while the system is running,and the terminals can't be locatedvery far from the main processorunit. Each processor must com-municate with the others through thecommon-service processor. Theycannot directly exchange informa-tion, nor can they have their ownprivate disks, printers, modems, andthe like.

Another product for multiuser,independent-processor sharing of adisk is the disk multiplexer (the Cor-vus Constellation is an example). Adisk multiplexer can be likened to avery fast rotary switch that cyclesaround looking to see if any of thecomputers connected to it wish to doa disk access. When it finds a request,it reads or writes the particular disksector and then goes on to the nextstation. The disk multiplexer ap-proach is quite simple and can be aninexpensive solution for many ap-plications. However, due to the verylow level of the requests that aretypically presented to the multiplexer(eg: read a sector and write a sector) itis generally limited in dealing with themore sophisticated problems thatarise in multiuser interactions.

A more sophisticated interface witha powerful software base is neededfor complex applications. Like the

multiprocessor systems previouslydescribed, there is no way forseparate stations to communicatedirectly. They must send their infor-mation to the multiplexer, where itgoes to disk, or may be temporarilybuffered in memory. If the centraldisk or multiplexer fails, all workcomes to a halt.

Networks Without Software

One of the central themes of a com-puter network is communications. Alarge number of companies now offercomputer networks that provide theability to transmit data from stationto station, but do not address thequestions of the necessary operatingsystem, programming language, andapplications software needed to makeuse of these networks. Basically,these units are peripherals with low-level drivers that permit data ex-change. While they are suitable forthose installations that have thenecessary system-programming talentto design, modify, and implement thechanges needed to take advantage ofthis facility, we will be focusing on in-tegrated computer-network systems.Very few vendors are willing to stepup to the complex software tasks in-herent in blending these technologiesinto a coherent system design.

Both Digital Research and 3COMprovide software without a network.Digital Research's CP/NET system

permits up to sixteen stations on ahost. These stations share the dataand devices on that central host.CP/NET is written without any par-ticular network communicationdevices in mind. Each hardware ven-dor may select a particular technol-ogy and protocol to connect thework stations to the host. Butalthough CP/NET provides a frame-work for multiuser software based onthe familiar CP/M environment, dueto the lack of support for applicationsin the languages and systems runningunder CP/NET, many companieshave chosen to develop their ownvariant of CP/M with their own shar-ing protocols.

3COM's UNET is a package writ-ten for the UNIX environment. It is asoftware implementation of a govern-ment-standard intercomputer proto-col, called TCP; it, too, leaves openthe question of how the computersare actually connected, and applica-tion programs must explicitly dealwith the network in a nontransparentfashion.

Attributes of a Local Network

A local-area network can bedescribed as a communications net-work that covers a limited geographi-cal area. Just what "limited" meansvaries substantially, from 0.1 km (ap-proximately 328 feet) to 10 km (ap-proximately 6.2 miles). Data rates on

APPLESCOPE

Interface for the Apple II Computer

The APPLESCOPE system combines two high speed analogto digital converters and a digital control board with the highresolution graphics capabilities of the Apple II computer tocreate a digital storage oscilloscope. Signal trace parametersare entered through the keyboard to operational softwareprovided in PROM on the Dl control board.

• DC to 3.5 Mhz sample rate with 1 024 byte buffer memory

• Pretngger Viewing up to 1020 Samples

• Programmable Scale Select

• Continuous and Single Sweep Modes

• Single or Dual Channel Trace

• Greater that or less than trigger threshold detection

Price for the two board Applescope system S595•Dealer Inquiries Invited

DIGITAL STORAGE OSCILLOSCOPE INTERFACES

For further informationcontact:

Circle 316 on inquiry card.

RC Electronics Inc.

7265 Tuolumne StreetGoleta, CA931 1 7(805) 968-6614

Combine an Apple II orS100 based computersystem with our interfacecircuit boards to create adigital storage oscillo-scope at a fraction of thecost of other storagescopes.

The S100 interface pro-vides an additional 1024bytes of buffer memory inplace of the PROM. Theuser must supply thegraphics display anddriving software. Price ofthe single board is $495.

TheSCOPEDRIVERisanadvanced software pack-age for the Applescopesystem. It provides ex-panded waveform man-ipulation and digitalsignal conditioning. TheSCOPEDRIVER is avail-able on 5'A" floppy disksfor S49.

96 October 1981 © BYTE Publications Inc

Start talkingbusiness

with your Apple

COBOL is the most effective business language,Apple II is the most friendly business computer.CIS COBOL with FORMS-2 brings together thebest features of COBOL and Apple to enable you todeliver the most effective, user-friendly applications.

Business Programmers: Take the COBOLexpertise you have acquired on big businessmainframes, and use it on Apple II to create friendlyapplications that will talk directly to your users -where it suits them best, on their own desks.

CIS COBOL's dynamic module loading givesyou big application capability and the FORMS-2source generator lets you build and modifyconversational programs from visual screenformats, creating much of the code automatically.

Application vendors: CIS COBOL withFORMS-2 steps up the pace for your developmentof the high quality professional applicationpackages needed today. And creating them inCOBOL makes them more maintainable.

Over half the Apple II's now being sold are goingto business or professional users so demand forquality applications is growing fast, creating bigbusiness opportunities for you,

Stability proven by the US Government.

CIS COBOL has been tested and approved for twoconsecutive years by the US General ServicesAdministration as conforming to the ANSI 74COBOL Standard. Apple II under CP/M is includedin CIS COBOL's 1981 GSA Certificate of Validation(at Low-Intermediate Federal Standard plusIndexed l-O and Level 2 Inter-ProgramCommunication),

Get your hands on CIS COBOL at yourApple dealer.

Talk business with him now!

Micro Focus Inc., 1601 Civic Center DriveSanta Clara, CA 95050, Phone: (408) 248-3982,

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CIS COBOL with FORMS-2 for use on the Apple II with CP/M is an Apple Distributed Product,CIS COBOLand FORMS-2 are trademarks of Micro Focus, CP/M is a trademark of DigitalResearch, Apple II Is a trademark of Apple Computer,

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no simple blackbox, either. It is asophisticated micro-computerwith2000charac-ters of memory, over 39special commands and theoption of doing typesettingon the IBM Model 50.

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a local network also vary over ordersof magnitude, from 100 K bps to 10M bps, and higher. But these bound-aries are far from sufficient tocharacterize the meaning of "localnetwork" today.

Compared to terminal-like devices,a local network generally has an inex-pensive communications medium andhigh data rates. Every node on thenetwork can communicate with everyother node, and the network requiresno central node or processor.Messages are "broadcast" over thecommunications medium, with adestination address included. Onlythe intended receiver is expected torespond, although other stations havethe capability of "listening in." Thus,a high level of security, such as foundin point-to-point networks, is notpresent unless cryptographic tech-niques are used. Local networks aremeant to be highly reliable, so thatany failing station will simply beunavailable, without interrupting thecommunications between the remain-ing stations. Similarly, it is possibleto add new stations without disrupt-ing the ongoing communicationsflow.

Due to the limited-distance natureof local networks, another standardfeature is the ability to connect multi-ple networks. This internetwork link,called a gateway, may be a high-speed link for networks that are closeto each other, or it may depend on amore conventional telecommunica-tions network for reliably transmit-ting data from city to city, or aroundthe world. Because of the multiplicityof emerging network technology, andthe variety of communications pro-tocols in use, gateways must be pro-vided to permit stations on one typeof network to exchange informationwith others on a different type orspeed of network. Both electrical andsoftware protocols must be convertedwhen passing data through thesegateways.

Origins of Local-Area Networks

Local-area networks evolved fromthe large-scale telecommunicationsnetworks developed in the 1960s. Asuniversities and research labs began

to install computers, the need arose topermit the flow of informationamong them. The underlying com-munications protocols (packettransmission) came from the long-distance networks. The communica-tions media (twisted pair or coaxialcable) were developed to supportvery high speed direct coupling be-tween computers.

One experiment significantly af-fected the nature of modern local-area networks: the University ofHawaii wanted to connect terminalsall over the Hawaiian islands to alocal computer and communicationsprocessor, and from there to othernetworks. They developed a systemcalled ALOHA, a packet radio-trans-mission system. No wires were usedto connect each station to the others,so techniques such as polling couldnot be used.

The scheme was elegant, andoperated in a manner very similar tothe way that telephone party lineswork. Each station would first listento see if anyone else was transmitting(in radio jargon, this was called "car-rier sense"). If not, the station wouldtransmit its message, including error-detection bits. As long as the totalfraction of available transmissiontime used was low, everyone got aturn—eventually. If two stationsfound the channel clear and startedtransmitting simultaneously, the twopackets would collide. This collisionwould scramble the information, butthe error-detection logic would throwaway the bad data. If the stationsdidn't receive an acknowledgment bya certain time, they would simplysend the packet again.

Studies of this scheme quicklyrevealed a number of problems, oneof the more serious being that as thenumber of messages grew, many col-lided, and only a small fraction of thetrue communications bandwidth wasused for valid data. Far more seriouswas the fact that if enough stationstried to transmit, less and less datagot through, and the result was con-tinuous collisions!

The Ethernet Network

Numerous refinements to the basic

98

October 1981 © BYTE Publications Inc

C #Pascal

Efficiency^-rortabilityFlexibility»otrong Typing

Now you don't have to compromise!

Whitesmiths Ltd. now offers portable language development systems for fourfamilies of computers. Approximately one thousand installations use oursoftware.

We support complete versions of both C and Pascal, as compilers and cross-compilers. You get C automatically when you license Pascal, and you getnative support with each cross-compiler. Test the software on your VAXbefore burning PROMs for your 68000 or 8080.

Whitesmiths Ltd. offers a variety of licensing arrangements, the simplestbeing a binary license for use on a single CPU. The full source code is avail-able with internal documentation. Maintenance, training and sublicensingrights may also be obtained.

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Idris is a trademark of Whitesmiths, Ltd. ■ Unix is a trademark of Bell Laboratories M CP/M is a trademark of Digital Research Company ■ VMS,RSX-11 /M, RSTS/E, LSI-11, VAX, are trademarks of Digital Equipment Corporation ■ VERSAdos is a trademark of Motorola Corporation

Protect .your software *SpeciaI °rder

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RO. Box 1132 Ansonia Station New York, N.Y. 10023 (212) 799-1200 Telex 645 592Distributors: Australia Japan United Kingdom

Fawnray Pty Ltd. Advance Industries Real Time SystemsHurstville, NSW Chiyoda-ku, Tokyo Newcastle upon Tyne02 570 6100 03-258-0839 0632 733131

Sfarwrifer

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Daisy Wheel Printer by C. Itoh 1750

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Qume (shipped FREIGHT COLLECT) 2499

Silentype w/interface 349

Amdek Color Monitor 349

Amdek Green Screen 169

Amdek/Leedex B/W 12" Monitor 129

NEC 12" Green Screen 239

Sanyo 9" B/W Monitor 169

Sanyo 12" B/W Monitor 255

Sanyo Green Screen 309

Dysan Disks (pkg. 10) 50

Memorex Disks (pkg. 10) 40

Opus Disks (pkg. 10) 30

Verbatim "Gold" (pkg. 10) 35

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Atari 400 8K Computer 419

Atari 800 16K Computer 789

Atari 410 Program Recorder 69

Atari 810 Disk Drive 499

Atari 820 Printer 429

Atari 825 Printer 695

Atari 850 Interface 169

16K RAM by Microtek 99

32K RAM by Microtek 189

Assembler/Editor 45

Atari Joysticks 18

Atari Paddles 18

Basketball 30

Computer Chess 30

Invitation to Programming 17

Music Composer 45

Star Raiders 39

Super Breakout 30

3-D Tic-Tac-Toe 30

Video Easel 30

Visicalc 180

Available for immediate shipment

Full 96-characterASCII with descenders

Adjustable tractor-typepin feed

• Interfaces —

'Standard — Centronics-style 8-bit Optional — PS232, IEEE488Parallel Duffer Size — one line

TO ORDER: Phone orders invited using Visa, Mastercard or bankwire transfers. Visa and MC service charge of 2%. Mail ordersmay send charge card number (include expiration date), cashierscheck, money order, or personal check (allow 10 business daysfor personal or company checks to clear). Please add 3% ($5.00minimum) for UPS shipping, handling, and insurance. APO andFPO include 5% ($700 minimum) for postage. Calif, residentsadd 6% sales tax. Please include phone number on all orders

FOREIGN ORDERS include 1% handling — shipped air FREIGHTCOLLECT only. Credit cards not accepted on foreign orders.All equipment is in factory cartons with manufacturer warrantyOpened products not returnable. Restocking fee for returnedmerchandise. Equipment subject to price change and avail-ability. Retail prices differ from mail order prices. WE SHIP THESAME DAY ON MOST ORDERS!

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APPLE SOFTWARE

ABM by Muse 19

Adventure by Mircrosoft 27

Alien Rain by Broderbund 19

Apple PIE 119

Apple Pilot 129

Apple-oids 25

Appleplot by Apple 59

Applepost Mailing List System 44

Applewriter Word Processor 65

Asteroid Field by Cavalier 19

CCA Data Mgmt 84

Data Factory by Microlab 129

Desktop Plan II 159

DB Master II by Stoneware 199

DOS Tool Kit 65

DOS 3.3 Upgrade 49

Dow Jones Portfolio Evaluator 45

Fortran by Apple 159

Hi-Res Football 33

Head-On 21

Integer Basic Cassette Demos 29

Orbitron 25

PASCAL Language System 425

Peachtree Bus. Pkgs CALL

Personal Filing System 84

Phantoms Five 29

Pool 1.5 29

Pulsar II 25

Raster Blaster 24

Robot War by Muse 31

Sabotage 21

Sargon II Chess Game 29

Snoggle/Puckman by Broderbund .. 24

Space Game Album by Budgeco ... 39

Space Eggs 25

Space Invaders/Cosmos Mission. ... 19

Space Raiders by USA 25

Star Cruiser 24

Sub-Logic FS-1 Flight Simulator 34

Super Single Disk Copy Routine.... 35

Super Stellar Trek 33

Supertext II by Muse 129

Ultima 35

Visicalc II 159

Visilist 24

Visitrend/Visiplot 219

Wizard and the Princess 32

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APPLE COMPUTERINTERFACE CARDS

Applesoft II Firmware Card 149

CCS Asynchronous 7710A 129

CCS Parallel Print Cd. 7720A 155

Centronics Interface Cd 179

Comm. Cd. & DB25 Cable 179

CPS Multifunction by Mtn. Comp. . . 199Expansion Chassis by Mtn. Comp. .. 555

HiSpeed Serial Int. Cd 155

Integer Basic Firmware Cd 149

ROMPLUS 135

SSm AIO Serial/Parallel I/OAssembled & Tested 149

ACCESSORIES

A/D D/A Board by Mtn. Comp 319

Andromeda 16K Ramcard 179

Apple Game Paddles 25

Arith. Processor 7811 A or B 339

COPYROM by Mtn. Comp 51

Dan Paymar L.C. Kit 1 or 2 55

Extender Board 27

GPIB IEEE 488 Card 259

Graphics Input Tablet 639

Hayes Micromodem 299

Introl X-10 Remote Control Sys 239

Joystick for the Apple 47

Keyboard Filter ROM chip 49

Lazer Lower Case Plus+ 49

M & R Sup-R-Term 80-col-bd 319

Music System by Mtn. Comp 479

Programmable Timer CCS 7440A ... 159

Prototyping Hobby Card 22

ROMWRITER by Mtn. Comp 149

SuperTalker Speech Synthesizer.... 239

Thunderclock 129

Versa-Writer Digitizer Drawing Sys . 239

Videx Keyboard Enhancer 115

Videx Videoterm 80-col-cd 319

Z-80 SOFTCARD by Microsoft 319

MEMBER CHAMBER OF COMMERCE

ALOHA scheme were developed, butthe most significant were developedat the Xerox Palo Alto ResearchCenter as part of an experimentalproject, called Ethernet, started in themid 1970s. (It was once thought thata universal medium called "lumin-iferous ether" was the carrier of elec-tromagnetic waves. Xerox decided tobuild its "ether" out of coaxial cable.)The Ethernet scheme could detect acollision in progress by reading backthe state of the cable as data were be-ing transmitted. Thus, a station couldsense when another station was send-ing data and stop transmitting, in-stead of continuing until the end of itspacket. (To guarantee that all suchstations recognized the collision, aburst of noise was sent prior to quit-ting.) A randomized delay functionwas added so that each station wouldwait a different amount of time, in-stead of beginning to transmit im-mediately after a previous transmis-sion was complete. This avoidedcausing a collision each time two ormore stations had something to send.The delays would get progressivelylonger as the channel became busier.

a)

c)

Using these modifications, anEthernet-style local network coulduse essentially all the bandwidth ofthe communication medium. Even asstations began sending ten times asmuch information as the channelcould handle, things no longer cameto a halt.

The Ethernet algorithms weredesigned to be simple. Every stationon the network manages its use in-dependently, so there is no need for amaster to control access. Simplicitywas important to ensure minimalbuilding costs and reliability. Otherschemes are considerably more com-plex, which makes them either dif-ficult or expensive to include in eachnode's interface.

Network Topology

Most early local networks used astar topology (see figure 1): a centralnode was connected via a radialcable to each of the other stations.Unfortunately, this system suffersfrom the consequences of a centralfailure. The entire system goes downif the center fails. But there are stillmany reasons to use a star network.

E__I

Figure Is Popular network topologies. The star network (la) is the most common of theearly network types (such as the telephone system), and relies on the central node forcontrol of operations. The ring network (lb) circulates all messages in one direction,and may employ tokens to specify which node may transmit; a failure of any node mayinterrupt network operation. Bus configuration (lc), as used on the Ethernet and bycable television, allows nodes to be added or removed without impairing the network.

Telephone exchanges are organized asstar networks, and many companiesalready have PBXs (private-branchexchanges). By using the PBX as alocal-area network for data as well asvoice communication, companies cantake advantage of the already existingwiring: this is most suitable for low-data-rate information, such as videoterminals.

A ring (or loop) topology connectsits stations in a closed network.Messages circulate in one direction,often being amplified and repeated ateach node they pass through. Again,a station failure can interrupt the en-tire message flow, but in some casestwo alternate parallel loops are pro-vided for reasons of reliability. Ringsoften use a form of control strategycalled a token. A token is a specialmessage that gives the receiving sta-tion permission to transmit. When afree token comes by a station thatwants to transmit, the token is re-moved and replaced by the message.Generally, the same station removesthis message when it comes aroundagain and reinserts the token.

Rings are most popular in process-control applications (eg: controllingequipment in manufacturing en-vironments). When dealing with theequipment being controlled, it is im-portant to be able to guarantee theworst-case maximum time necessaryto send a message to some station,say to close a valve. Token systemscan provide a solution to this prob-lem. The random nature of theEthernet scheme might prevent a sta-tion from sending a critical messagein time. (Actually this is a bitmisleading. Ethernet can be used tobuild token-like control that requiresstations to avoid sending a messagejust because they see the net is free;they have to wait to receive the con-trol token first.)

Much of the ring approach hasbeen developed in England, par-ticularly at Cambridge University,where numerous computers and ter-minals have been interconnectedusing a simple but high-speed inter-face. Several British companies arenow developing commercial versionsof the Cambridge Ring interface unit.

102 October 1981 © BYTE Publications Inc

>E

>ALANTII

The next generationof business software

WHAT'S IN A NAME?

We've chonged the name of our producl line. Originally, we called ourproducts "Phoenix" because we saw the phoenix as an appropriatesymbol of quality. Unfortunately, a lot of other companies chose Phoenixas well, and there was some concern that the market place wouldbecome confused.

Our new name, PALANTIR™ (pronounced pa/'anteer), is not a new name~", It comes from J.R.R. Tolkien's Theji umu unuiuci ^ alack crystal ball, a "seeing stone",used to see things at a distance.

Whatever the name on the package, ihe software in the package hasn'tchanged. It is still the highest quality business software you can buy foryour microcomputer.

WORD PROCESSING

We know word processing. A year-and-a-half ago ihe owners ofDesigner Software'" wrote a well-known word processor for anothercompany. In the last 18 months we've learned about other features youwant in a word processing package. PALANTIR™ Word Processingreflects our experience. It is more powerful than other word processingpackages you can buy and can compete, feature for feature, with expensive dedicated word processors.

Many people have remarked that the user's manual we wiote earlier wasthe best ever for microcomputer software. Even so, we felt that we couldhave made it more accessible to the non- technical user. With PALANTIR"

.',7' ,V- r'*'7*.

Word Processing wo have a separate Training Manual wilh beginning,intermediate and advanced levels. By allowing you to work at your ownlevel, we have made the learning process easier and less intimidating.

ACCOUNTING

Alt five PALANTIR" general accounting packages (General Ledger, Ac-counts Receivable and Payable, Payroll and Inventory) were designed byCPA's based on similar packages from mini and mainframe computers.The programs are COBOL wilh an integral assembly-language database. They are integrated to allow automated posting to the GeneralLedger. An internal screen handler permits full-screen data entry forspeed and ease of use. Although we made cosmetic enhancements priorto distribution, the basic programs have been user-tested for ot leasteighteen months.

PALANTIR™ Accounting also includes a growing number of specificapplication packages. We have completed or scheduled for completionFixed Assets, Tenant Processing, Mail Management, Financial Projec-tions and Time/Billing. Each package stands alone, but many also work inconjunction with other PALANTIR™ packages. For example, MailManagement will work very well by itself, but we also designed it to fit ineasily wilh the merging capabilities of Word Processing.

With all PALANTIR™ Accounting we have given special attention todocumentation. Not being content to describe which buttons to push, we

grams and how each package helps to automate your office.

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Bus topology is quite simple, beingmerely a long length of cable thatruns past each station. Stations areconnected to it at the nearest point,and can be added or removed withoutaffecting any other station. A stationcan be added in two ways: the buscan be split, temporarily disruptingcommunications, and a new stationinserted, or, more commonly, taps(devices developed by the cable TVindustry that literally pierce the cablefrom the outside, making contact tothe inner conductor and the outershield) can be installed while stationsare transmitting. Even temporaryshorts will only garble some packets,and they will be retransmitted oncethe short is removed. The Ethernetuses this form of interconnection.

What Frequency, What Wire?

Another significant parameter inthe description of a local-area net-work is the particular medium used tosend the information between sta-tions. Local networks have usedtwisted pair, multiconductor flatcable, coaxial cable, optical fibers,and even infrared light transmittedthrough the atmosphere. Within eachof these categories, numerous choicesabound in the frequency used fortransmission and the details of themodulation technique.

The most fundamental split intechnology revolves around frequen-cies used on coaxial cable. You canthink of coaxial cable as a simplewire. If someone wants to send infor-mation, the wire can be left at 0 V orraised to some nonzero voltage.Another station can detect thechanges in voltage and decode the in-formation. This is generally referredto as baseband transmission, since thefrequency spectrum generated startsat 0 Hz (direct current) and goes upfrom there.

Television transmission is sent atvery high frequencies (typically 50MHz to 100 MHz). A central carrier-frequency is modulated up and downto transmit the information. At thesefrequencies, the cable has far less at-tenuation than in the basebandregion, so a transmitter can broadcastover miles of cable instead of being

limited to several thousand feet. Andthe blossoming cable-TV industry canprovide the necessary devices at avery low cost due to the largevolumes they are expected to producefor standard television reception. RF(radio-frequency)-modulated systemscan also provide much higher band-widths than baseband, so the cablecan, in principle, be shared alongwith voice- and video-transmissionsystems.

RF systems (also known as broad-band), while very attractive, do re-quire a central retransmitter to re-ceive the data sent from each stationand rebroadcast it, much amplified,at a different frequency that each sta-tion is expected to listen on. The re-quired unit is expensive, even for thesmallest system, and if that unit fails,the network is unavailable until theretransmitter is back in service.

Local-Area Network Standards

Numerous local-area networkproducts have already been an-nounced, and new entries are madedaily. In almost every case, themanufacturers have developed theirown hardware and software pro-tocols. These, naturally, are incom-patible with everyone else's!

The exception to the above incom-patibility is the Ethernet specificationreleased in November 1980 by DEC(Digital Equipment Corporation), In-tel, and Xerox Corporation. Based onyears of actual experience with an ex-perimental version of Ethernet com-munications, the "tri-company stan-dard" was provided, with every detailof the electrical and low-level com-munications protocols defined. Thesecompanies are trying to encouragethe adoption of this scheme amongcomputer and peripheral manufac-turers; indeed, many large and smallcompanies have publicly an-nounced their adoption of the DIXEthernet system, and are busy design-ing and building products.

The DIX Ethernet system uses abaseband-transmission scheme, witha 10 Mbps data rate. It provides forthe use of a large number of stationsand packet formats, with 48 bitsallocated for a unique world-wide

104 October 1981 © BYTE Publications Inc

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station address that is not duplicatedanywhere, and it has a large (32-bit)checksum on each packet to detecterrors.

This scheme pushes thetechnological requirements by oper-ating at such high speeds and usingthe particular packet format andchecksums adopted. Without spe-cially designed VLSI (very large scaleintegration) devices to handle the net-work interface, it is expensive tobuild an Ethernet interface. For exam-ple, Intel has announced a MultibusEthernet interface (the iSBC-550) thatcosts about $4000. To that you mustadd several hundred dollars for ananalog interface (the transceiver unit)to connect between the interfaceboard and the physical cable. It is ex-pected that volume production of theneeded components will begin withinthe next two years and prices willdrop dramatically.

One means of lowering the effec-tive cost is to share the Ethernet inter-face among several stations. Anumber of companies (such as Xerox,

and Ungermann-Bass) offer amicrocomputer-based Ethernet inter-face with four to eight ports for con-necting terminals or other microcom-puters. The effective cost per stationcan be reduced to between $500 and$1000 for a fully loaded system.

Standards Organizations

While product activity continues,several committees are attempting todevelop an industry-wide standardfor local-area networks. The IEEE (In-stitute of Electrical and ElectronicsEngineers) Computer Society Local-Network Committee (Project 802) hasbeen meeting for over a year to try toestablish a viable standard, and thestandard is still in a state of flux.Fierce battles have been raging amongthe committee members representingdifferent local-network interests. TheIEEE standard has been evolving in amanner that attempts to accom-modate many diverse applicationareas and functional requirements.

The framework for defining a com-munications network is based on a

highly layered series of protocolsdeveloped by the ISO (InternationalStandards Organization), called theOSI (Open System Interconnection)protocols. The OSI architecturedefines seven layers of commun-ications.

Layer 7, the Application layer, pro-vides for the identification of usersand services, and is responsible for in-itiation and reliability of datatransfers, as well as general networkaccess, flow control and recovery.Utility programs may perform net-work file-transfers, terminal-to-network support, etc.

Layer 6, the Presentation layer, isprimarily responsible for making dataavailable to the Application layer in ameaningful fashion. The Presentationlayer takes care of protocol conver-sion, data unpacking, translation, orencryption.

Layer 5, the Session layer, is usedto set up and break communicationspaths across the network and managethe exchange of data. It is responsiblefor multiplexing and demultiplexing

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106 October 1981 © BYTE Publications Inc

Circle 22 on Inquiry card.

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messages, managing the sequencingand priority of these messages, andproviding the needed buffers.

Layer 4, the Transport layer, pro-vides another level of connectionsbetween network entities. This layermanages the connections andsegments messages into smaller piecesthat the network can support. It mayalso be involved in error and flowcontrol, as well as additionalmultiplexing activities.

Layer 3, the Network layer, is thelevel that actually determines how toget a message from one network toanother (since many paths may exist).The Network level may use severalintermediate hops to get informationto its ultimate destination and, thus,needs to know how to route packetsthrough the network. It, too, may beinvolved in sequencing and error-and flow-control activities.

Layer 2, the Data-Link layer, iswhere the actual packet formats areestablished, along with the particularaccess control mechanism used toregulate use of the physical network.

Data is encapsulated in packets thatcontain physical addressing informa-tion, error-detecting checksums, etc.

Layer 1, the Physical layer, definesthe electrical and mechanical inter-faces to the network. The Physicallayer specifies the particular signalingmeans (baseband vs RF, for instance),the modulation technique adopted,station-identification addresses, etc.

The current activity of the IEEE 802committee is focused on specifyingLayers 1 and 2, the Link and Physicallevels. Similarly, the DEC/Intel/Xerox Ethernet specificationaddresses only these two levels ofprotocol.

It appears that the 802 Committeeis converging on a standard thatoffers many alternatives within oneframework. Even the issue of datarate (specified by Ethernet as 10 Mbps) appears to be an optional value(such as 1, 5, 10, or 20 M bps). Theerror detection used may be either a16- or 32-bit CRC (cyclic redundancycheck) code, and the access methodmay be either a token-like scheme or

1

NETWORK A

USER 1

I

USER ACCESSES FILESON FILE SERVER

FILE SERVER

I

FILE SERVER

PRINT SERVER ACCESSESFILES ON FILE SERVERFOR USER 2

USER 2

USER 2 REQUESTSPRINT SERVICEFROM PRINT SERVER

PRINT SERVER

I

INTERNET SERVERACCESSES FILES ONFILE SERVER ON BEHALFOF USER ON ANOTHERNETWORK

I

INTERNET SERVER

1

USER 3 ACCESSES FILESON ANOTHER NETWORK

USING INTERNET SERVER 1

■ NETWORK B

Figure 2: The server/client relationship on local networks. Perhaps the most significantadvance in communications is that, under this scheme, the computer system is fullydistributed; there is no master node, so each node can call on others when resources areneeded. Some nodes are dedicated to special functions, such as controlling hard-diskmass-storage devices, or printing.

a CSMA/CD (carrier-sense, multipleaccess with collision detect) schemeresembling (but not identical to) theEthernet system. While the 802 Com-mittee deliberates, manufacturerscontinue to develop their ownsystems. It is possible that some maymodify their products once standardsactivities are resolved.

Recently, attention has been givento the higher levels of protocols. TheNational Bureau of Standards is pro-posing a series of Transport andhigher-level protocols. It is unfor-tunate that the work on the higher-level protocols does not precede thelowest-level issues. The advantage oflayered protocols is that the underly-ing levels can be changed in waystransparent to the higher levels, whilethe converse is not true, but the stan-dards activities are not moving in thatdirection.

Servers and Clients

The most significant contributionin the local-area network field is notthe communications aspect, but thedevelopment of a whole new way ofbuilding computer systems. Thefundamental organization describedby Xerox assumes a fully distributedcontrol mechanism (see figure 2).There is no master-slave relationshipamong stations; they all com-municate and cooperate with oneanother. Any number of stations(called servers) on a local networkmay provide services to other stations(called clients). Typical server func-tions are: mass-storage file system,printer support, time-of-day clock,translation of symbolic names intophysical addresses, data-basemanagement support, gateways toother networks or computers, andother specialized hardware support.Servers may also be clients of otherservers on the network. For instance,the printer server may be a client ofthe file-system server in the course ofserving its own clients.

Servers are distinguished on thenetwork merely by the software theyrun and any special hardware theycontain. A station that is willing tolisten to requests from other stations(using a higher-level protocol they

108 October 1981 © BYTE Publications Inc

tS, Incorporated

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For serious application development, MDBS III offers major advantages in these seven key areas:

Extraordinary data structuring

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(State)

(Zip)

MAIL TO: Micro Data Base Systems, Inc.P.O. Box 248-BLafayette, IN 47902

Circle 224 on inquiry card.

agree on) can perform a server func-tion.

In order to maintain a high level ofreliability, the logical functions of theservers are usually implemented usingseparate physical computers. Onecould merge all of the above servicesinto one larger computer, but in do-ing so would end up with somethingresembling a conventional centralcomputer system.

Putting It All Together

Clearly, the local-area networkfield is too broad to cover in greatdepth. Most of the attention hasfocused on nonpersonal computersystems, such as large mainframes orterminals. We will describe the NestarCluster/One Model A system.

The Cluster/One Model A is alocal-area network system based onthe Ethernet principles, but itsimplementation has been optimizedfor the connection of low-cost AppleII personal computers. The systemwas first announced in January 1980and has been used around the worldfor almost two years. It includes in-tegrated software and hardwarefeatures needed to provide a com-prehensive data-processing and data-communications facility, and thesystem permits either independentoperation of individual stations, witha full complement of local periph-erals, or a share in the larger, morereliable peripherals via the local net-work. The work station in questioncosts between $1000 and $2000, socost constraints differ from those ap-plied to networking work stations inthe $10,000 to $20,000 price range.Nestar chose to implement many net-work functions via simple program-mable hardware, and assigned manyfunctions to software. Another deci-sion influenced by these cost factorsinvolves network speed. The speed ofthe Cluster/One was decided by thereasonable cost for a personal com-puter network interface and the band-width requirements needed for thework typically done by these per-sonal computer work stations.

The Model A network operates at240 kbps—almost a thousand timesfaster than a 300-bps telephone link,

and 40 times slower than the XeroxEthernet system. This was the fastestrate that could be supported bynetwork-interface software runningon the 6502 host processor of theApple II computer and still allow datachecksums to be performed on themessage packets.

The choice of the network mediumwas also influenced by the basic costgoal. Rather than taking 8-bit datafrom the Apple memory and thenserializing and deserializing it, it wasdecided to transmit the data in an8-bit-wide parallel fashion, which notonly reduced the interface cost, butincreased the inter-bit transition time.This has the effect of permittingessentially arbitrary interconnectiontopology for the Nestar network,something not found in any othersystem. The Nestar network is notrestricted to a linear-bus topology,but can be wired as suits the par-ticular installation requirements.

Network Design

The overall system designresembles the Ethernet scheme. Nosingle critical component must func-tion for network communication totake place. All station-to-stationcommunication is direct, with acarrier-sense algorithm executing inthe ROM- (read-only memory) basedprotocols in each station interface.The interface is passive, so stationsmay be added or removed from thenetwork during operation. Stationsnot in use may be turned off untilneeded.

In the Model A network, thecarrier-detect function is im-plemented using a dedicated controlline, which indicates the bus is busy.Stations do not transmit until they seethat this line is available. The elec-tronics of the bus interface permitreading of data just written. How-ever, it is not necessary to performfull collision detection. At the start ofa packet transmission the address ofthe station attempting to send is firstput on the bus, and then read back. Iftwo stations do this simultaneously,at least one will not read back its ownaddress and will detect a conflict.Even this is rare, since each station

has a random waiting algorithm thatavoids most collisions that wouldoccur at the end of a previoustransmission. Once this initial colli-sion detection has been passed, thecarrier signal has been establishedand further collision detection is notnecessary. The rest of the packet issent, like ALOHA, without collisiondetection. After the initial check,later collisions can result only fromerroneous stations, and not undernormal conditions.

Each packet of data contains initialheader information, followed by upto 256 bytes of data and a 16-bitchecksum. Once the packet is trans-mitted, the receiving station immedi-ately acknowledges the receipt of thepacket (if the checksum matches thedata) or else requests a retransmis-sion. This error-control algorithm iscompletely contained in the ROM-based protocols on the Nestar inter-face, and permits higher levels of soft-ware to work with reliable and cor-rectly sequenced data. The ROM pro-tocols are also responsible for takingmessages longer than the 256-bytepacket size and splitting them intomultiple packets, each with its ownchecksum. Thus the four lowestlayers of the OSI protocols are sup-plied as part of the logic on board theNestar network interface.

The Model A network also includesa variety of network servers and thesoftware needed to make their useliterally transparent to current ap-plications. The Nestar Network FileServer runs on an Apple II microcom-puter interfaced to the network. Itcan support a variety of devices,ranging from two 8-inch double-sidedfloppy disks, to 66 megabytes ofhard-disk storage. Larger capacity isavailable by using more than one fileserver. The network software allowsmultiple file servers on one local net-work, thus giving essentiallyunlimited online storage capacity.The data on these reliable, sealedWinchester disks can be "backed up"using Nestar's compact cartridge-tapestreamer drive. A single cartridge canwrite and check over 20 megabytes ofdata in twelve minutes.The Network File Server can also

110 October 1981 © BYTE Publications Inc

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With the Landlord™ apartment managementsoftware and an Apple II* computer, file cabinets full ofpaperwork and the frustrations of cumbersomebookkeeping procedures can be eliminated, Theclerical work for your apartments can be accomplishedwith greater accuracy in a fraction of the time youpresently spend. The Landlord™ will keep up-to-date fileson apartments and residents as well as detailed recordsof property income and expenses,

You'll be able to enter, change, or delete informationby following the simple English instructions that appearon the screen of the Apple II*. The Landlord™ willautomatically organize and store your data and makeit available for your review at any time. With theLandlord™, your resident manager can instantlydetermine where apartment vacancies exist and whenadditional units will become available for rental. TheLandlord™ also keeps track of resident payments, letting

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you see at a glance who is behind on rent or otherpayments, Property and tax analysis reports are printedautomatically each month and allow you to monitorthe profitability of your apartments,

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BYTE October 1981

111

contain a real-time clock/calendar,which stations can interrogate. Thisfacility is used to timestamp the crea-tion, access, modification, andbackup times of network files. Filesare organized with a tree-structuredsystem similar to a UNIX directory;they can be password-protected in avariety of ways to ensure that onlyauthorized users can create, modify,or otherwise access network data.

The software provided makes theuse of this data straightforward fromany Apple II work station on the net-work. All of Apple's current operat-ing systems (DOS 3.2, DOS 3.3,Pascal 1.0, and Pascal 1.1) can bedirectly loaded over the network.Modifications are made during thisprocess so that stations can logicallyconnect to virtual disks on the net-work shared disks (either from key-board commands or from programs).These disks need not have the samecapacity as 5-inch floppy disks, butmay be much larger or smaller. Eachstorage area is allocated the ap-propriate size for the application;

users may be executing programs inany set of languages or operatingsystems at the same time.

Network Applications

The Cluster/One network has beenused in a variety of applications thatinclude general office-automation en-vironments, engineering and softwaredevelopment sites, educational andentertainment uses, and special turn-key applications, such as travel-agency and real-estate systems.

To support this variety of uses,Nestar provides a number of general-purpose computing products. Otherservers, such as print servers support-ing a multiplicity of printers, areavailable. Communications serverssupport internetwork activity. Ap-plication programs for general data-base access, interoffice electronicmail, and teleconferencing, have beendeveloped by Nestar, either in-houseor in conjunction with the suppliersof popular packages for the Apple II.The collection of hardware and soft-ware capabilities makes this network

attractive for a wide range of applica-tion areas.

What's Next?

There seems to be little doubt thatthe current interest in local-area net-works and personal computer workstations will continue to grow overthe next few years. As stationsbecome more powerful and sophisti-cated in both systems software andapplications programming, they willreplace an even larger fraction of con-ventional minicomputer systems. Asmanufacturers provide fully in-tegrated VLSI components designedfor very high performance networks,they will be incorporated into the per-sonal computer local-area networkinterfaces. Whether or not the stan-dards activities will stem the pro-liferation of de facto standards re-mains to be seen. The emergence ofnetworks of personal computers hasopened up a whole new set ofchallenges for programmers indeveloping real-time, multiuser, in-teractive systems. ■

^—— MARYMAC INDUSTRIES, INC

In Texas Orders

Questions & Answers

1-713-392-0747

21969 Katy FreewayKaty (Houston) Texas 77450

To Order1-800-231-3680800-231-3681

SAVE BIG DOLLARS ON ALL TRS-80 HARDWARE & SOFTWARE

TRS-80 BY RADIO SHACK. Brand new in cartons delivered. Save state sales tax.Texas residents add only5% sales tax. Open Mon.-Sat. 9-6. We pay freight and insurance. Come by and see us. Call us for a refer-ence in or near your city. Ref: Farmers State Bank, Brookshire, Texas.

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References from people who havebought computers from us probablyin your city

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112 October 1981 © BYTE Publications Inc

Circle 212 on inquiry card.

Circle 342 on inquiry card.

MicroMed™ and MicroDent™ make your practice perfect!"

They're the real solution to the problems confronting everyphysician's and dentist's office. Each is a unique package,developed through years of work in close conjunction withdoctors and dentists. They'll help you treat your patients moreefficiently and accurately, while saving you timeand money in the process.

Versatility.

Whether you are in private practice or a member of a busygroup, there's sufficient capacity to handle your needs.Thousands of patients can be accommodated on floppies,and even more on hard disk. MicroMed and MicroDentcan easily handle everything in your practice from billing topatient records to complex insurance forms. With millionsof hours of actual use in medical and dental officesthroughout the country, they stand alone at the top,in a class by themselves.

We know you're after solutions, not more problems. Ourmenus are simplicity itself, and are designed for yourconvenience (not our programmers'). The computer displaysyour options at every step. What could be simpler?Your own office staff can easily take care of the routineso that you can devote your valuable time to your patients.

You are the boss.

Forget about problems with outside billing services ormanual record-keeping. You exercise absolute control overyour billing procedures. Finger-tip patient recall lets you knowinstantly whose accounts are due and what services wereperformed. Account aging is automatic, and past-due noticesor statements are printed and addressed, ready for mailing.All types of reports may be requested to help you betterunderstand your finances and cash flow. Daily backupsare created automatically.

Multiple Insurance Forms.

Many patients have several different types of insurancecoverage. With MicroMed and MicroDent you can enter almostany form, keep track of which patients it applies to, and get itprocessed and ready for mailing. When new forms come out(as we all know they will) you don't have to pay for customprogramming, you can modify the form print format yourself.With our exclusive Fgjrnulator'" system it takes just minutes.

The biggest surprise of all is that MicroMed and MicroDentare just $1500 each. Plus, having your own office computerprovides you with great tax advantages. If you like what yousee, contact your nearest computer store. They can provideyou with MicroMed or MicroDent on any CP/M® basedcomputer for an amazingly economical price. Or, if you alreadyhave a computer, a demo disk and manual set is availablefor just $75, and allows you to run the entire program.The manual separately is $50. Send for one today, andmake your practice perfect!

> Automatic billing for any patient load

> Handles practices with up to 20 doctors

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• Full transaction and treatment details1 Cumulative totals by doctor

• Profitability analysis reports' Mailing list maintenance1 Can be linked to word-processing' Appointment recall with reminders< Maintains hospital and lab codes

1 Keeps track of referring doctor codes

Demo disk and manual set $75!

Dealerships are available to established computer vendorson a territorial basis.

'"MicroMed. MicroDent. and Formulator are trademarks of SoftwareHows^•CP/M is a registered trademark ol Digital ResearchCopyright "1981. SoftwareHows

P.O. Box 36275, Los Angeles, CA 90036(213) 731-0876 . TWX: 910-321-2378

Prepare Your Programfor Publication

C A Johnson

3619 Sugarhill Dr

San Antonio TX 78230

"When I get my personal computer, I'm going to makeit pay for itself. I have some ideas for programs thateveryone will want to buy." Such dreams are shared bymany prospective microcomputer buyers, some armedwith a college programming course, others with ex-perience writing programs for business.

What these aspiring software authors usually don'tknow is how to prepare a program with the best possiblechances of being accepted, published, and marketed. As aresult, they enter the highly competitive software marketwith a disadvantage that may even guarantee failure.

But programmers' pipe dreams can have happy end-ings. If you want to write software for publication, con-sider these steps toward success.

Look at the Market

The first step in writing a marketable program is toconduct your own market analysis before choosing yoursubject. If the market is already cluttered with programssimilar to the one you're considering, yours won't stand achance unless it includes a special feature that will grabthe attention of potential buyers.

Games and simulations have enjoyed great popularitysince the beginning of the microcomputer age, and theyprobably always will. But the universe can hold only somany versions of Star Trek, and any microcomputerused for game playing already has at least one. The gameis still fun, but the market has worn thin.

Star Trek is only one example of a game that has beenprogrammed to death. Dozens of versions of Nim, SlotMachine, Guess the Number, Dice, and many othergames are stacked knee-deep in the marketplace at give-away prices. Chess might be an exception because of itsperennial appeal, but a new chess program won't attractattention without a record of strong tournament play.New versions of old games assail software publishers like

so many attackers on the video screen. But publishers canmake unlimited use of the ultimate weapon: the rejectionslip.

Finding a Subject

Adventure games and sword-and-sorcery games arethe most popular simulations now. They bring the excite-ment of storytelling and role playing into computer enter-tainment.

Games that spring from your own imagination holdmore promise than rehashes. Literary classics can also in-spire games. Stories like Gulliver's Travels and TheVoyages of Sinbad contain excellent dramatic situationsthat can serve as the basis for games with wide appeal. Sodo 1984, Animal Farm, and many romantic classics.Don't overlook game and puzzle books; they often con-tain the seeds of intriguing situations.

When you choose a game situation, make sure itchallenges the player. To offer a challenge, the gamemust encompass a complex and variable winning strategyfor the player. If the winning strategy is fixed, the playerwill soon discover it, and the game will cease to be fun.Although you can create difficult games by arranging fora high-probability random function to "kill" the player,such games are more frustrating than challenging. Theplayer shouldn't get "killed" in the middle of the gameunless he uses faulty strategy or makes some othermistake. If the player plays with care and uses an in-telligent strategy, he should win.

Lively graphics add appeal and enjoyment to bothsimulations and games. Try to dream up striking visualeffects that advance the story line of your program.

Use Your Own Interests

Your best and most marketable program may wellspring from your own interests and experiences. If you

114 October 1981 © BYTE Publications lnc

Finding the best softwareon the market can take you weeks.

Reading this ad takes 317seconds and gives you the same

results!

The Westico Software Review Committeeis easy to recognize. It's their red-rimmed eyes. You get that waychecking through an endlessparade ot software programs.And they do it so that youdon't have to. But selectinggood software is only partof what makes Westico oneof the fastest growing com-panies in the software industry.Having experts on staff whoreally understand both softwareand hardware is another. But Westicooffers more than quality products and

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• Automatically apportions firmoverhead expenses to jobs inprogress • Provides early detectionof potential budget overruns* Mon-itors profitability of jobs in progress

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• Job accounts receivable registerSystem & documentation — $595Documentation alone — $20

Inventory Control forManufacturers

This system includes standard in-ventory control functions such asmaintaining and reporting on thestatus of the inventory stock as wellas maintaining records of all trans-actions made against part num-bers in stock. In addition, it supportsmulti-level bills of materials (BOM's),the creation of multiple partnumber transactions for jobs basedon those BOM's, the tracking ofjobs through work-in-progress, thegeneration of material require-ments reports based on manufac-turing schedules.

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golf, bowl, or play tennis, perhaps you could write a pro-gram for computing players' handicaps or for schedulingand managing tournaments. Tournament directorswould be a natural market.

Depending on your interests,, you could considerwriting programs that manage stock portfolios, catalogstamp collections, or make an inventory of personalproperty. Other possibilities are programs that recordprogress in training activities or dieting and then displaythe data graphically. Hobbies and club activities such asscouting offer dozens of possibilities.

If you have trouble coming up with a good programidea, get some friends together for a brainstorming ses-sion. To stimulate everyone's imagination, choose a fieldin which you feel reasonably competent, then describe ingeneral terms some program that's been thoroughly ex-ploited. Think of a few variations on that program.

The most important thing to remember about brain-storming is never to reject or belittle a suggestion, nomatter how trivial or ridiculous it may seem. Don't riskturning off anyone's imagination. Once the session getsrolling, it will have its own momentum. Write downevery suggestion, or better still, tape record the session.One brainstorming session with a few intelligent peoplewill yield enough material to keep you busy writing codefor years.

Remember the Hardware

When choosing the subject of your program, anotherthing to keep in mind is the capacity of the computer onwhich the program will run. The most popular computersobviously offer the biggest market. If at all possible, scalethe program for a popular machine.

Once you've selected your subject, you can startwriting the program. It's important to write readablecode. Readability not only makes the program easier foryou to debug, it also endears you to customers who needto adapt the program to their particular systems or tastes.

Not So Fast!

When the program is finished, debugged, and runningperfectly, stop! Don't send it to a publisher yet. Now isthe time to add those finishing touches that make the dif-ference between a good program and one that is reallycommercial and marketable.

Study your program with a critical eye. Ask yourself,"Does my program contain all the instructions the userwill need?" Make sure the instructions are thorough,clear, correct, and free of misspellings and grammaticalerrors.

Then ask, "Does my program lead the user through it?Is it conversational and personal?" A game, for example,doesn't pit just any anonymous soul against the villain.

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New in-depth report tellsyou how-at savingsof up to $40,000

"Contemporary Applications of OpticalBar Code Technology" is a new, compre-hensive report from North AmericanTechnology that can save you thousandsof dollars in research and development

time when programming and equippingyour small computer for bar code.Written by the originators of ByteMagazine's experiments with publicationof software in printed form, Walter Banksand Carl Helmers, this report is the onlycomplete presentation of materials onkeyless data entry using modern bar codetechnology. It will enable you to:

• Read HP-41C calculator formats intoyour Apple, or other suitable computer.

• Prepare and deliver machinereadable printed software to yourcustomers.

• Read a UPC code into your personalcomputer.

• Print Code 39 manufacturing inven-tory tags with your formed characteror dot matrix printer.

Here, in clear, concise, understandablelanguage is all you need to know aboutbar code history, software engineeringrequirements, complete machine inde-pendent Pascal software in sourcelisting form. There is software

to generate and read all majorformats from Code 39 to HP-41C, andUPC to the new NATI text software pub-lication format You get information youcan use to program your small computerfor bar code without detail processing bya human operator. This method speedsthe operation, eliminates translation andentry errors and, where desirable, permitsthe use of unskilled personnel for theentry function. You save thousands ofdollars as a result The $500 purchaseprice of the report includes license forthe commercial modification and use ofall software contained therein.For detailed information, send for ourbrochure. There is no cost or obligation.Mail the coupon today.

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Please send me your FREE brochure on"Contemporary Applications of Optical BarCode Technology."

NAME

ADDRESS

CITY

STATE ZIP

116 October 1981 © BYTE Publications lnc

Circle 267 on inquiry card.

The finestData Base

*MGINB0CI° Arable

<Maxi

DATA MANAGEMENTPROGRAMCOMPARISON CHART

FIELD TYPES

Alphanumeric

Yes

Yes

Yes

Yes

L Yes

Numeric

Yes

Yes

Yes

Yen

No

Fixed decimal numeric

Note A

Yes

Yes

No

No

Date (MM/DD/YY)

Yes

NO

Yes

No

No

Extended date (MM/DD. YYYY)

No

No

Yes

No

No

Calculated equation

NoteS

Note 6

Yes

No

No

Permanent fields

Yes

No

No

No

No

Machine language assisted

No

Yes

Yes

Note 7

Yes

Sort by any field

Yes

Yes

Yes

res.

Number of Sort Key files

1

1

5

i

Numeric sort

Yes

Yes

Yes

No

Ascending sort

Yes

Yes

Yes

Yes

Descending sort

Yes

Yes

Note 1 1

Yes

Sort wuhin a selected range

No

No

Yes

No

Sort multiple fields simultaneously

Yes

Yes

No

No

FILE MAINTENANCE

Fixed length input fields

Yes

Yes

Yes

Yes

Yes

Single key entry of common data

No

No

Yes

No

No

Single field EDIT selection

Yes

Yes

Yes

Yes

Yes

Skip record (next or previousl

Yes

Yes

Yes

No

Yes

Search & EDIT record

No

Yes

' Yes

No

Yes

Search & DELETE record

No

Yes

Yes

NO

No

Auto rejection of alphanumeric dataill numeric field

Yes

No

Yes

No

No

RECORD SELECTION TECHNIQUES

Record number

Yes

Yes; Yes

Yes

No

Bmary search (high speed)

No

: No :

Yes

No

No

Maximum a of simultaneous keys

■r,-:

■■ ..A ■■■■■■

10

31

1

RELATIONAL. COMPARISONS

Equal

NO :

Yes:

Yes

Yes

Yes

Not equal

No

Yes::

Yes

No

Yes

Greater than

No

..Yes.;

Yes

Yes

Yes

Less than

No

Yes

Yes

Yes

Yes

Instnng

Yes

No

Yes

Yes

No

AND/ OR

No

No

Yes

Yes

No

W,ld card masking

No

No

Yes

No

No

User specified page title

Note 8

Yes

Yes

No

Note iO

User specified column headings

No

No

Yes

No

Yes

Automatic page numbering

Yes

Yes

Yes

Yes

Yes

Right justification

No

Yes

Yes

No

No

User defined column widths

Yes

No

Yes

Yes

Yes

User defined column separators

No

No

Yes

No

No

Keyboard entered columnar values

No

No

Yes

No

No

Merge data into form letters

No

No

Yes

No

No

Form filling applications

No

No

Yes

No

No

Columnar totals

Yes

Yes

Yes

No

No

Columnar subtotals generated uponchange in a specific field

Yes

Yes

Yes

No

No

Built m screen print

No

No

Yes

No

No

MISCELLANEOUS

Cost

$75.00

$94,90

$99.95

$99.00

$79.95

Punctuation allowed within data fields

Yes

>

Yes

Yes

Yes

Upper / Lower case

Note 3

Note 3

Yes

Note 3

Note 3

Built in RS-232< driver

Note 3

Note 3

Yes

Note 3

Note 3

Built-in TRS-232 driver

Note 3

Note 3

Yes

Note 3

Note 3

Programmer'S interface

Note 9

Note 9

Yes

No

Note 9

Sample DATA disk

No

No

Yes

No

No

Documentation (» of pages)

■ T'\:

■:'■ U~l

120

38

29

NOTE I- Filt li.liNOTE 2 S*qu*r».alNOTE 3 Uitr mullNOTE 4- Ho.d copyNOTE 5- Four fundNOTE 6 Swn* oi ncNOTE 7 A.o.labliNOTE B l20cWocNOTE 9 Ooto tttvtiNOTE 10 132 chorocNOTE 11 Uitropnoi

t proqrom (or $99.95

rndrng ordu).

The jury is in and the verdict is . . . "outstanding!"Reviews from all of you who purchased MAXIMANAGER (not to mention raves by many topmicrocomputing magazines) have heralded it as thedefinitive data base managing system. We knew thatbusiness owners and hobbyists demanded the finestdata base managing system available. To all of youwho praised us for MAXI MANAGER, we extend ourthanks. And to those of you who have yet to try MAXIMANAGER, we invite you to experience this incrediblesystem today. But don't take our word for it (or ourjury's). Judge for yourself.

JUST CHECK SOME OF THESE FEATURES

Supports six different relational search techniques.Comes with programmer's interface.Over 120 pages of documentation.

Supports up to 20 user defined fields of 40 characters each.Record length up to 800 characters.Files can be up to four disks in length.Compatable 35, 40, 77 & 80 track drives with properoperating system.NHas calculated equation fields.Complete report generator.Works hand in hand with any word processor.

MODEL 1 version requires TRSDOS 2.3 and is compatable withNEWDOS 2.1 & NEWDOS 80

MODEL 3 version comes on TDOS, a special version of the DOSPLUSoperating system.

Requires 48K of RAM and one disk drive minimum.

Model

Order

Circle 12 on inquiry card.

BYTE October 1981

117

The player who faces all the dangers your program holdshas a name. Your program should ask the user's nameand call him by it frequently.

Now ask, "How does my program treat the user?" Cutemessages are okay if used sparingly and in good taste, butnever be condescending or insulting to the user. Remem-ber that the user bought your program to perform sometask or to have a good time. If he enters a response thatisn't in the accepted input range, don't tell him he's anidiot. Tell him what the accepted input range is.

There is nothing so discouraging as running a programand finding yourself facing a prompt without knowingwhat kind of input is expected, or seeing attackersswarming across the screen when you don't know howyou're supposed to defend yourself. If the programdoesn't make clear at all times what input it expects, thenyou owe the user the courtesy of a way to ask for help.

Remember that the user is also your customer. If youtreat him with respect, he'll consider buying your nextprogram. These finishing touches are just as important tothe program as the most intricate code.

Don't Forget Testing

Is the program ready to go to the publisher now? No,not until it's been tested. Bring in a friend and give himthe program to load and run. Don't give him any help.Watch every detail as he works his way through the pro-gram. Make notes both for changes in the program and

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for anything that seems appropriate to put in the user'sguide.

If your friend has trouble with the mechanics of theprogram (not in developing a game strategy), review thegame later to see if ambiguous or inadequate instructionscaused the problems. If your friend gets hopelessly stuckand you are forced to help him, you must face the factthat you have either a flawed program or a less-than-brilliant friend. You'll probably feel better if you blamethe program and go back to work on it.

After correcting problems discovered in the first testrun, bring in a different friend and repeat the usabilitytest. This isn't because you're no longer speaking to thefirst friend, but because you need another naive user. Ifthe second friend can use and enjoy the program, youmay be ready to write the documentation. If the secondfriend has problems, you'll have to revise the programand find a third friend. If you run out of friends, you'llprobably find that enemies are better at testing softwareanyway.

You can't test a program too much. Once you'resatisfied that the program is usable, you can beginwriting the documentation.

Before you started work on the program, did you writedown the things you wanted it to do? If so, you may beable to modify your notes as a starting point for the user'sguide. You should also use your notes from all the testruns.

A user's guide should be written in the simplest wordspossible. Don't try to show off your vocabulary or provehow ingenious you were in writing the program. Invite afriend to read the first draft and offer criticism. Insist thathe point out any places where the user's guide is unclear,ambiguous, or overwritten. Don't be upset if the firstdraft requires extensive changes. After you make therevisions, type or print a fresh copy on good paper. In-clude a title page, a copyright notice, and a table of con-tents. Then place the user's guide in a binder that looksgood and makes turning the pages easy.

Now Is the Time

Now, finally, you're ready to submit your program toa publisher. The user-friendly program and the profes-sional-looking user's guide will greatly increase the likeli-hood of acceptance. The user's guide may also providethe basis for advertising copy when your program goes topublication.

Amateurs are writing many of the programs submittedfor publication today, and the lack of professionalismoften shows. It shows in programs that have bugs, poorinstructions, incorrect spelling and grammar, and shoddyor incomplete documentation. Most of all, it shows in thechoice of unsalable subject matter.

Take the time and effort to make your program lookand perform as if a professional had written it. At thevery least, you'll be proud to run the program on yourown system. And there's a good chance your effort willpay off in more sales and hard cash.H

118 October 1981 © BYTE Publications Inc

Circle 65 on inquiry card.

Cameo Makes Your MicroBig Enough for Big Business

When you want a data base for your micro thatwill grow as fast as you do — look to Cameo.Whether your business is commercial, educa-tional or institutional — for large inventories,massive mail lists, extensive accounts receivableand effective cash management — Cameo hasthe system to meet your needs.

Cameo's Cartridge Disk Subsystem providesreliable mass storage for most popular micros*.The Cameo subsystem gives you up to 100 timesthe storage capacity of floppies, while retainingthe same flexibility that floppy media provide.With Cameo's system you can remove, copy andback-up massive amounts of data quickly andeasily. And, byte-for-byte, cartridge disk massstorage is more economical than floppy disks.Even today's new technologies cannot give youthe reliability, flexibility and back-up capabilitythat Cameo provides.

Circle 59 on inquiry card.

Installation and start-up is simple. Cameo's sub-system is compatible with most operating systems,eliminating the need for additional complex pro-gramming. Make Cameo your micro mass storageconnection. Call today for the location of the dealernearest you.*Apple, TRS-80 Model I & II, Heath H89 and most S-100's

Cameo Electronics, Inc.

1626 Clementine StreetAnaheim, CA 92802(714) 535-1682

See us at ComdexEuropean Distributor

Cameo Electronic Vertriebs-GmbhEscherstrasse 3, D-8121 EberfingWest GermanyTel: 8802-8363 TELEX: 59903

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The 820 RO PACKAGE includesmachine mounted paper tray andcable. A compressed print optionand device forms control arestandard features.THE 820 KSR PACKAGE includesfully ASCII Keyboard plus all of thefeatures ol the RO.

<%>

CLEARANCE ZENITH COLORVIDEO MONITOR $349.

SUPER SELLING TERMINALS FROMLEAR SIGLER/We have the follow-ing Lear Siegler terminals in stockat prices too low to print! Call forquotes.

ADM-3A/Industry's favorite dumbterminal for some very smartreasons/

ADM-3A + NEW from Lear Siegler.CALL!

IT IS HERE! It is the new Intermedi-ate Terminal from Lear Siegler.

SANYO MONITORS AT LOW COM-PUMART PRICES/Sanyo's new lineof CRT data display monitors aredesigned lor the display ol alpha-numeric or graphic data.9"SANYOB/W $169.

12" SANYO B/W12" SANYO W/

GREEN SCREEN13" SANYO COLOR

MICRO

The originaland most complete catalogof micro-com-puters, acces-sories andperipherals.

Sanyo 13" Color Monitor

NEC COLOR MONITOR/RECEIVERHIGH RESOLUTION/

Composite video using BNC con-nectors. 8-Pin connector for VCR/VTR video loop In/Out andtelevision reception.

Visit our giant

ANN ARBOR STORE

1250 North Main StreetAnn Arbor. Michigan

FREE CATALOGS

DEC PDP/

LSI-IT Systemsconfigured andintegrated withother manufac-turers compat-ibles. The first,best DEC basedsystems catalog.

foitbem!

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HP-41C CALCULATORSMEMORY MODULES for storingprograms of up to 2000 lines olprogram memory."EXTRA SMART" CARD READER.Records programs and data backonto blank magcards.THE PRINTER. Upper and lowercase. High resolution plotting. Port-able thermal operation.APPLICATION MODULES

NEW SUPER 41-CV SYSTEMS with

Quad RAMS built-in. Maximum

memory on-board leaves slots

open tor Application Pacs and

peripherals.

+ CARD READER

+ CARD READER + PRINTER

QUAD RAMS equivalent to tour

Memory Modules all packed

into one.

MATROX PRODUCTS/Compumart

stocks the complete line.

DEC LSl-11/Compumart now

offers the entire product line.

CALL FOR PRICES AND DELIVERY

NOVATION CAT ACOUSTICMODEM Answer Originate.

NEW! D-CAT Direct ConnectModem from Novation.

Giltronix Switch

NEW! GILTRONIX RS 232 SWITCH/

The ultimate in flexibility. You canconnect three peripherals to onecomputer or three computers toone peripheral. Switches the eightmost important RS 232 signals.

DYSAN DISKETTES/Single side,single density. Hard or Soft Sector$5. ea.

MEMOREX 3401,s/51/4"disks $3.25./with hub ring lor Apple $3.50.

MEMORY INTEGRATED CIRCUITS/

Call lor quantity discounts whenordering over 50 units.

MOTOROLA 4116 (200 Nano-second Plastic) $4.50

*5P

^

V

RM EXPANSION ACCESSORIESFOR AIM-CALL SPECS AND PRICES

APPLE in IS IN STOCK/Apple Hi

Information Analyst Package —128K Apple III. Black and WhiteMonitor 12". and information ana-lyst software.

TOP SOFTWARE PACKAGES FROMCOMPUMART

VISICALC/FOR APPLE/FOR HP/FOR COMMODORE/FOR ATARI

SOFTWARE FROM APPLE/ApplePlot (the perfect graphic comple-ment for Visicalc/Dow Jones News& Quotes/Apple Fortrom/AppleWriter/Pascal Language System/Controller Business System

PERSONAL SOFTWARE/Visidex/

VisiTrend/VisiPlot/VisiTermMUSE/Super Text

Apple Soltware

MOUNTAIN COMPUTER/

Expansion accessories for Apple/Super Talker/The Music System/ROM plus board with Keyboardfilter/ROM Writer/Clock Calen-dar/AtoD and Dto A Converter/Clock for Apple/CPS MultitunctionBoard

VIDEX/Video Term (80 col. x 24line. 7x9 Matrix plug in compati-ble board for Apple II) w/wographics EPROM/SSM Serial 8;Parallel. Apple Inlerface/ABT'sNumeric Key Plan/CaliforniaMicrocomputer Keyboard

***X

VIC 20 PERSONAL COMPUTERFROM COMMODORE

$299.

SEE US AT THE NORTHEAST COMPUTER SHOW, OCTOBER 15-18,1981, BOOTH #608

IMPORTANT ORDERING INFORMATION

CALL, BOO 343-5504, in Massachusetts: (617) 491-2700, phones openfrom 830 a.m. to 700 pm. Mon-Frt WOO a.m. to 400 p.m. Sat.PCs, Accepted from Dun 8c Bradslree! rated companies—shipment

contingent upon receipts ol signed purchase order.SALE PRICES Valid lor month ol magazine date onty—all pnces sub-ject lo change without notice. Our Ann Arbor retail store is openUOO a m. to 7O0 p.m. Tues-Fn. lOOO a.m. to 500 pm. on Saturdays.

$1895 $4695

SAVE OVER $200 ON OUR BESTSELLING APPLE SYSTEM/ Systemincludes a 48K Apple II. AppleDisk, DOS 3.3 and Controller and aSup R MOD RF Modulator.

List S2209.EXCLUSIVE FOR THE APPLE:Magic Wand. Videx, Z-80 soitcard(Requires 48K Apple and disk).

COMPLETE SUB-SYSTEM $925.

APPLE ACCESSORIES

CHOOSE FROM: Silentype Printer

w/x face/Light Pen/Easy Writer

(80 col. need a Videx)/C 1 ock for

Apple.

FROM MICROSOFT: 16K RAM

Board/FORTRAN.

FROM COMPUTER STATION:

Hi-Res Dump for 460 Printer.

OUR APPLE INVENTORY IS COM-PLETE. WE'VE GOT IT ALL-

CRISP LETTER QUALITY OUTPUTUNSURPASSED EASE OFOPERATION

This Compumart/Commodoresystem includes a COMMODORE8032 32K CPU, a 4040 DUAL DISK,a C-ITOH PRINTER and x/face andWORD PRO 4 PLUS (all cables in-cluded). List S5685.

EDUCATORS: COM MODOREHAS EXTENDED ITS 3 FOR 2 DEAL

A COMPLETE SYSTEM: includesa DUAL DISK DRIVE/TRACTORPRINTER and an 80 COLUMN32K CPU. No interfaces needed.Cables included. List S3985.

COMPUMART $3635.SAVE $200 ON COMMODOREACCESSORIES WITH PURCHASEOF A 32K PET-SAVE $100 WITH AI6KPET.

CHOOSE FROM:

Visicalc/Word Pro 4/Wordcraft 80/Ozz the Informa tion Wizzard/Dow Jones Portfolio Mgmt System/Assembler Development Package.

$3250

This Basic 16k BYTE system(expandable to 32k) includes:CRT DISPLAY, THERMAL PRINTER,MAGNETIC TAPE CARTRIDGE,6 ROM CAPACITY VIA ROMDRAWER, 4 IO PORTS. COMMUNI-CATION-HPIB.RS232

PLUS

YOUR CHOICE OF 4 SOFTWAREPACS OR TWO OF OUR "BESTSELLERS"-(VISICALC, GRAPHICSPRESENTATION, INFORMATIONMANAGEMENT)

HP-83 SYSTEM

This Basic System from Hewlett-Packard includes HP-83/ROMDRAWER/MASS STORAGE ROM/51/4" SINGLE MASTER FLEXIBLEDISK DRIVE/HP-IB INTERFACEMODULE/2 METER HP-IB CABLE.COMPLETE SYSTEM $4249.

ty

$795

FROM ROCKWELLOur AIM Starter System for Educa-tional 8: Laboratory use includes4K AIM/BASIC 8c ROM/ASSEMBLER8c ROM/POWER SUPPLY EG1 EN-CLOSURE/CRAIG TAPE RECORDER.

ACCESSORIES FOR AIM STARTER:

PL 65 High Level Language/Paperfor the Aim (roll)/Rockwell's 4 slotMotherboard/

WE ALSO CARRY RM EXPANSIONACCESSORIES FOR THE AIM-65.

Rockwell InternationalAuthorized DealerAccept No Less

Jappta computer

Authorized DealerAccept No Less

s

'lw% HEWLETT PACKARDAuthorized DealerAccept No Less

Qcommodore

Authorized DealerAccept No Less

c

Systems

800-343-5504

IN MASS CALL 617-491-2700

COMPUMART

65 Bent Street, Dept 110

PO Box 568, Cambridge, MA 02139

From THE LEADER... '

We just might be the largest independent small systems dealer in the country. Here's why:

COMPUMART has been serving the computer needs of industry since 1971.

We stock, for immediate shipment, only those products from the finest micro-computermanufacturers.

And any product, except software, can be returned within 10 days lor a full refund—evenif you just change your mind. We also honor all manufacturers' warranties. Our experttechnicians will service any product we sell

Call us tor more information on products, product configuration and service. Our phonesare open Monday thru Friday, 8:30 a.m. to 7:00 p.m. and Saturday llOO am. to 400 p.m.

We have a staff of highly knowledgeable sales people waiting to hear from you, andto help. Because service is what we're all about.

Circle 76 on inquiry card.

System Notes

List Pager

Allan Lovett, 20024 N 18th Dr, Phoenix AZ 85027

List Pager, shown in listing 1, is a simple program forthe Apple II or Apple II Plus computer. The programprints out listings, one page at a time, with a title on thefirst page and a number on each of the following pages. Itwill not split statements between pages but will insteadautomatically produce line feeds to move to the nextpage. You can choose either a full 80-column format or60 columns with margins on each side. List Pager is writ-ten in Applesoft BASIC, is set up for a Centronics 730printer, and requires one floppy-disk drive.

To use List Pager, the program to be listed must first becaptured as a text file. This can be done using a programsuch as Capture, which is found on page 76 of the AppleDOS manual. When List Pager is run, it will ask for the

C Compiler only $75

We have re-written Small-C as published by Ron Cain in theMay, 1980 issue of Dr. Dobbs. The Code Works C compiler(CW/C) includes these additional features:

• Structures and unions

• For, switch/case, do-while

• Multidimensional arrays

• Conditional compilation (#ifdef,etc.)

• Assignment operators, e.g. x += 10;

• Can declare complex types, e.g. int (*fp)[5];

• User supplied I/O buffers of any size

• Dynamic storage allocation (alloc and free)

• Command line arguments using argv and argc

• Improved error handling

CW/C is a proper subset of the full C language. We do not have:float, double, long, unsigned or short data types; static; initial-izers; sizeof; typedef; "?:"; casts; bit fields; goto; #undef, #if,#line.

CW/C generates assembly language source code that isthen assembled using ASM or MAC. CW/C supports inlineassembly language with the #asm ... #endasm preprocessorcommands. Requires 56K 8080 or Z80 CP/M system. Distributedon single-density 8" disk or Northstar double density CP/M 5"disk. Includes an excellent User Manual, the executable CW/Ccompiler, runtime library, and several useful example programswritten in C.

theCODEWORKS

CW/C is $75, including shipping in the US and Canada.CA residents add 6% tax. Visa and MasterCard welcome.CP/M is a registered trademark of Digital Research.

Box 550, Goleta, CA 93116 805-683-1585

title of the program, the name of the text file, and if anoffset (60-column format) for hole punching is desired.After this information is entered, it will print the listing.This program greatly improves the readability of alisting over that of continuously printed listings, whichalways seem to have an important line written on the per-forations between pages. ■

Listing 1: The List Pager program printed in a 60-column for-mat with 10-column margins. The. List Pager can also list pro-grams in full 80-column format. List Pager places a title on thefirst page of a listing and numbers on subsequent pages. Theprogram is written in Applesoft floating-point BASIC for theApple II or II Plus computer with one disk drive and a Cen-tronics 730 printer.

TOO D* ■ CHR* (4>:T* ■ CHR* (1): ONERR GOTO 390

110 RO « 0!LM = 1

120 HOME ! HTAB (15)t PRINT "LIST PAGER"! PRINT ! PRINT

130 INPUT 'TITLE IS ? ">TITLE*J PRINT I PRINT

110 PC ■ 2

150 INPUT "TEXT FILE IS ? "!TF*! PRINT

1(40 LW = 80

170 PRINT "OFFSET FOR HOLE PUNCH ? <Y/N> "i! GET AN*! PRINT

T*!AN*180 IF AN* » "Y" THEN LW ■ AOJLM = 10190 HOME ! PRINT D*!"PR*1"ZOO PRINT CHR* <9);"80N"

210 OS = ((80 - LEN (TITLE*)) / 2>I HTAB (OS)! PRINT TITLE*! PRINT CHR* (10): PRINT CHR* (10)220 PRINT D*;"0PEN "!TF*230 PRINT D*;"READ "!TF*240 PL = 4

250 PRINT CHR* (9>!"80N"260 LN* = ""!L1* = "■

270 GET A*! IF LEN (LN*) < 210 THEN LN* = LN* + A*! GOTO 280

275 IF LEN (LN*) » 240 THEN LI* = LI* + A*2B0 IF LN* ■ CHR* (13) THEN GOTO 260290 IF A* = CHR* (13) THEN GOTO 31030 0 GOTO 27 0310 PRINT t*;:le = 1320 LH " LEN (LN*) + LEN (L1*>:l.E = 1! FOR I - 1 TO .10! IF

LH > (LW * I) THEN LE » I + 1: NEXT I330 FOR I « 1 TO LE! IF I * LW < 241 THEN L*(I) ■ MID* (LN*r((I - 1) x LW + 1),LW)

335 IF I I LH > 240 THEN L*(I) « MID* (Lit, (((I - 1) * LW+ 1 ) - 240).LW)

339 NEXT I

340 PL ■ PL + LE

350 IF PL > 60 THEN PL = PL - LE! FOR I = 1 TO 64 - PL! PRI

NT CHR* (10)! NEXT ! RO = 1! GOTO 380

340 FOR I = 1 TO LE: HTAB (CM)! PRINT L*(I>! NEXT

370 GOTO 250

380 PRINT CHR* (10)! PRINT TAB( 60)i"PAGE ";pG!PG ■ PG +

1! PRINT CHR* (10)! PRINT CHR* <10>!PL = 4: IF RO = 1 THEN

LE » LE! FOR I = 1 TO LE: HTAB (LM)! PRINT L*CI>: NEXT iPL= PL + LE! GOTO 250390 PRINT T*400 PRINT D*!"CLOSE"

410 FOR I = 1 TO 67 - PL) PRINT CHR* (10)! NEXT420 PRINT D*;"PR*0"I HOME ! END

122 October 1981 © BYTE Publications Inc

Circle 69 on inquiry card.

COmWTCR UJflRSHOUSS

CALL TOLL FREE

ATARI

Special 32K 800

800 w/32K, recoraiders, joysticksAbove W/48K.

System

rder. star

800(16K)

400

810 Disk Drive.825 Printer. . . .850 Interface. .410 Recorder. .830 Modem..

16K Memory.32K Memory.

DISK DRIVES

Lobo

Apple 1st Drive. .Apple 2nd Drive.

MODEMS

Novation

CAT

D-CAT

Apple Cat IIAuto Cat...

PRINTERS

C. Itoh

25CPS-Serial..25CPS- Parallel.40CPS-Serial..45CPS- Parallel.Datasouth

DS 180

Diablo630 RO

w/Tractors. . . .630 RO

wo/Tractors. . .1640 RO

w/Tractors. . . .1640 KSR

w/Tractors. . . .1650 RO

w/Tractors. . . .1650 KSR

w/Tractors. . . .Epson

MX-80

MX-80 F/T

MX-100

Fric. Feed Opt.

for MX-80

NEC

PC-8023A

5510 RO

w/Tractors. . . .5520 KSR

w/Tractors. . . .Okidata

Microline 80. . .Microline 82-A. .Microline 83-A.Microbe 84Qantex

Serial

Parallel

Texas Instruments

810 Basic

810 Loaded

S930S990

S744CallS440S575S120S70S140

S75S150

$490S410

S155S155S349S235

S1380$1325$1825$1710

$1275

S2295S2100$2485$2740$2985$2885

CallCallCall

$50

Call

$2662

$2995

$375

$535

$790

$1115

$1150$1125

$1250$1450

1800-528-1054

A

ATARI

Novation

data systems

NorthSta^

^^/TECHNOLOGY, INC. ^^ AClGVlCiCO

3M Texas Instruments

EPSON fllBT CaUfomia

epson America, inc. ■■ H Computer

OKIDATA *SI Systems

VIDEO TERMINALS

Adds

Viewpoint Call

Soroc

iq 120 Call

iq 130 Call

IQ 135 Call

iq 140 Call

Televideo

910 C $589

912 c $694

920 C $744

950 C $935

Zenith

Z-19 S769

DISKETTS

Scotch

5V 0. 10. 16 Sector

(Qty 100) $250

8 0, 32 Sector

(Qty 100) $260

COMPUTERS

Altos

ACS 8000-15 Call

ACS 8000-2 w/CPM Call

Northstar

Horizon II 64K DD S2875

Horizon II64K QD $3150

Zenith

Z-89 48Kw/CPM $2200

MONITORS

Panasonic9" B&W S150

Sanyo

9" B&W $150

12'Green $240

CALIFORNIA

COMPUTER SYSTEMS

64K Dynamic Memory. . $500

16K Static Memory $255

Floppy DiskCont $285

Serial Asynch Board. . $110

Prices & availability subject to change without notice Personal checks will delay shipping two weeks

CDmPUTER

2222 E. Indian School Rd. • Phoenix, Arizona 85016Order Line: 1-800-528-1054JQPCLIQIJCC Other Information: 602-954-6109

"^^^^■™^™"^^™^™ Store Hours: Tues.-Fri.10-5 MST Saturday 10-3 MST

Prices reflect 3% cash discount. Product shipped in factory cartons withmanufacturers warranty. Add 2%, a minimum of $5, for shipping and handling.

If you can beatthese prices,you must havea brother-in-lawin the business.

16 K RAM KITS

NEC 4116 200 ns

DISKETTES

MD 525-01.10.16MD 550-01.10.16MD 577-01.10,16MD 557-01.10.16FD 32 OR 34 -9000FD 32 OR 34 -8000FD 34-4001

DISKETTE STORAGE

5'/4" PLASTIC LIBRARY CASE

8" PLASTIC LIBRARY CASE

PLASTIC STORAGE BINDER WITH INSERTS

PROTECTOR 5V<"

PROTECTOR 8"

17.95

26.5044.5034.8045.6036.0045.6048.60

2.50

3.50

9.95

24.95

29.95

INTEGRATEDCOMPUTER SYSTEMS

ITHACA INTERSYSTEMS

ALTOS

ZENITH Z89

CALIF COMPUTER SYSTEMS

MORROW DESIGNS

CALLCALLCALLCALLCALL

PRINTERS

ANADEX DP 9500 1295.00

ANADEX DP 9501 1295.00

CENTRONICS 739 765.00

C-ITOH 25 CPS PARALLEL 1440.00

C-ITOH 25 CPS SERIAL 1495.00

C-ITOH 45 CPS PARALLEL 1770.00

C-ITOH 40 CPS SERIAL 1870.00

C-ITOH TRACTOR OPTION 195.00

EPSON MX-80 $CALL

EPSON MX-80 F/T ' $CALL

EPSON MX-100 GRAPHIC SCALL

EPSON GRAPHICS ROM 90.00

IDS-445G PAPER TIGER 779.00

IDS-460G PAPER TIGER 945.00

IDS-560G PAPER TIGER 1195.00

1NF0SCRIBE500 9X9. 150CPS 1495.00

MALIBU 200 DUAL MODE 2995.00

NEC SPINWRITER 3510 SERIAL RO 2099.00

NEC SPINWRITER 3530 PARALLEL RO 2099.00

NEC SPINWRITER 7710 SERIAL RO 2595.00

NEC SPINWRITER 7730 PARALLEL RO 2595.00

NEC SPINWRITER 7700 D SELLUM OPTION . 2795.00NEC SPINWRITER 3500 SELLUM OPTION .... 2295.00

OKIDATA MICROLINE 80 399.00

OKIDATA MICROLINE 82A 599.00

OKIDATA MICROLINE 83A 899.00

OKIDATA MICROLINE 84 1199.00

MODEMS

NOVATION CAT ACOUSTIC MODEM 145.00

NOVATION D-CAT DIRECT CONNECT MODEM 155 00NOVATION AUTO-CAT AUTO

ANSWER MODEM 219.00

NOVATION APPLE-CAT 349.00

UDS 103 LP DIRECT CONNECT MODEM . 175 00UDS 103 JLP DIRECT CONNECT/AUTO

ANSWER 209.00

DC. HAYES MICROMODEM II (Apple) .. . 299.00

D.C. HAYES 100 MODEM (S-100) 325.00

D.C. HAYES STACK Smart Modem (RS 232) .. 249.00

LEXICON LX-11 MODEM 115.00

APPLE HARDWARE

VERSA WRITER DIGITIZER 219.00

ABT APPLE KEYPAD 119.00

MICROSOFT Z-80 SOFTCARD 299.00

MICROSOFT RAMCARD 170.00

ANDROMEDA 16K CARD 170.00

VIDEX 80 X 24 VIDEO CARD 299.00

VIOEX KEYBOARD ENHANCER 99.00

M&RSUPERTERM80X24VIDEO BOARD ... 315.00

NEC 12" GREEN MONITOR 235.00

SANYO 12" MONITOR (B&W) 249.00

SANYO 12" MONITOR (Green) 279.00

SANYO 13" COLOR MONITOR 469.00

TEECO 12" HIGH RES GREEN MONITOR 169.00

SSM AIO BOARD (INTERFACE) A&T 165.00

SSM AIO BOARD (INTERFACE) KIT 135.00

SSM IEEE 488 INTERFACE 369.00

124

BYTE October 1981

Circle 14 on inquiry card.

MOUNTAIN HARDWARE

CPS MULTIFUNCTION BOARD

209,00

SUPERTALKERSD200

259.00

ROMPLUS WITH KEYBOARD FILTER

. 179 00

ROMPLUS W/0 KEYBOARD FILTER

130 00

KEYBOARD FILTER ROM

49 00

COPYROM

49 00

MUSIC SYSTEM

.... 459.00

ROMWRITER

149.00

APPLE CLOCK

252.00

A/D + D/A

299.00

EXPANSION CHASSIS

575.00

VISTA COMPUTER CO.

APPLE 40 Track Drive A40 (163 K Bytes)APPLE 80 Track Drive A80 (326 K Bytes)APPLE 160 Track Drive A160 (652 K Bytes)

APPLE 80 Column Card

APPLE 8 Inch Disk Drive Controller

389.00549 00799.00329.00549.00

CALIF. COMPUTER SYSTEMS

S-100 BOARDS

2200A MAINFRAME 349.00

2032A 32K STATIC RAM ... 599.00

2065C64K DYNAMIC RAM 499.00

2422 FLOPPY DISK CONTROLLER & CP/M 339.00

2710 FOUR SERIAL I/O 249 00

2718 2 SERIAL/2 PARALLEL I/O 269.00

2720 FOUR PARALLEL I/O . 199.00

2810 Z-80 CPU 249.00

APPLE BOARDS

7710A/D ASYNCHRONOUS SERIAL

INTERFACE 139.00

7712A SYNCHRONOUS SERIAL INTERFACE 149 00

7424A CALENDAR/CLOCK 99.00

7728A CENTRONICS PRINTER INTERFACE 99.00

APPLE SOFTWARE

MAGIC WINDOW WORDPROCESSOR 89.00

MAGIC WAND 275.00

WORDSTAR-APPLE 259 00

MAILMERGE-APPLE (REOUIRES WORDSTAR) 90.00

SPELLSTAR-APPLE (REQUIRES WORDSTAR) 169.00

DATASTAR 199,00

EXPEDITER II APPLESOFT COMPILER . 89.00

PFS; PERSONAL FILING SYSTEM 79,00

PFS: REPORT GENERATOR 79.00

ASCII EXPRESS TERMINAL PROGRAM 59.95

Z-TERM COMMUNICATIONS SOFTWARE 89.95

MICROSOFT FORTRAN 165.00

MICROSOFT COBOL 550.00

OB MASTER 2.4 179.00

VISICALC 3.3 169.00

VISIPLOT 149.00

VISIDEX 169.00

CCA DATA BASE MANAGER 99 00

A-STAT COMPREHENSIVE STATISTICS PKG 119.00

APPLE GAME SOFTWARE

SPACE EGGS

24.95

POOL 15

29.95

RASTER BLASTER

24.95

GORGON .

32 95

APPLE PANIC

24,95

CP/M SOFTWARE TRS-80 MOD I HARDWARE

MICROSOFT BASIC-80 299.00 PERCOM DATA SEPARATOR 27 00

MICROSOFT BASIC COMPILER 319.00 PERCOM DOUBLER II . 159.00

MICROSOFT FORTRAN-80 399.00 DOUBLE ZAP It/80 45.95

PEACHTREE SYSTEMS CALL TANDON 80 TRACK DISK DRIVE 429.00

MAGIC WAND (REQUIRES CP/M) ,... 275.00 TANDON 40 TRACK DISK DRIVE 299.00

WORDSTAR (REQUIRES CP/M) . . . 325.00 LNW DOUBLER WITH DOSPLUS 3 3D 169 00MAILMERGE (REQUIRES WORDSTAR) 110.00SPELLSTAR (REQUIRES WORDSTAR) 199,00

DATASTAR 249 00 TRS-80 SOFTWARE

SPELLGUARD . 239.00 NEWDOS/80 2 0 MOD I 139 00

CP/M PICKLES & TROUT FOR TRS-80 II 175.00 LAZY WRITER MOD I 125 00

PROSOFTNEWSCRIPTMODI.III 99.00

MORROW DESIGNS special delivery modi.m 119.00

X-TRA SPECIAL DELIVERY MOD I.Ill 199.00

FLOPPY DISK SYSTEMS trackcess mod i 2495

OMNITERM SMART TERMINAL MOD I,III 89.95

Controller. PS . Cables. Microsoft Basic. CP/M. A&T MICROSOFT BASIC COMPILER FOR MOD I 165.00

DISCUS I (Single Drive—250 K) 799.00

DISCUS I (Dual Drive—500 K) . 1429.00 *»|"IDW||C

DISCUS 2D (Single Drive—500 K) 869.00 CORVUS

DISCUS 2D (Dual Drive-1 MEG) 1499.00

DISCUS 2+ 2 (Single Drive —1 MEG) .1099.00 f-Sln I II Hb-UU

DISCUS 2+2 (Dual Drive—2 MEG) 1999.00 MOD 1,11

HARD DISK SYSTEMS C°n,r°"er CaSe/PS' °Pera"n9 SyS'em' A&T

5 Megabytes 3095 00

Controller, P S, Microsoft Basic. CP/M. A&T 10 Megabytes 4495 00

DISCUS M10 (10 Megabytes) 2949.00 20 Megabytes 5395 00

DISCUS M20 (20 Megabytes) .. 3829.00 MIRROR BACK-UP 700 00

DISCUS M26 (26 Megabytes) 3949.00

SUPPLIES

DECISION 1 COMPUTER

AVERY TABULABLES

Z-80A. CP/M. NIX (UNIX Identical). 32 to 1 MEG of

memory 1.000 3Y? X ,s,6 8.49

Floppy and/oi Hard Disk CALL 3.000 3V? X ,v16 14,95

5,000 3'/2 X "/„ 19.95

SD SYSTEMS

S-100 BOARDS UARC° PAPER (PriC6S F0B- SP>

VERSAFLOPPY II A&T 389.00 9% X 11 18 lb white ... 29.00

VERSAFLOPPY II KIT 329.00 14% X 11 18 lb white 39.00

SBC 200 (Z-80 CPU) A&T 369.00

SBC 200 (Z-80 CPU) KIT 299.00 We stock a complete line ol computer covers, printer rib-

Z-80 STARTER KIT ... 289.00 bons. print wheels & NEC thimbles-CALL US FOR YOUR

EXPANDORAM II KIT (OK) 220.00 NEEDS

We built a reputation on our prices and your satisfaction.

We guarantee everything we sell lor 30 days II anything iswrong jus) return the iterr and we II make it right And olcourse we II pay the shipp ng charges

We accepl Visa and Mas'er Card on all orders COD orcersaccepted up lo $300 00 We also accepl school purchaseorders

Please add $2 00 lor standard UPS shipping and handlingon orders under 50 pounds, delivered in ihe continental U SCallus tor shipping charges on items thai weigh more than 50pounds Foreign FPO and APQ oiders please add 15% forshipping California residents add 6% sales lax

The prices quoted are only valid tor stock on hand and allprices are subject lo change without notice

(213) 883-8594

31245 LA BAYA DRIVE, WESTLAKE VILLAGE, CALIFORNIA 91362

Circle 14 on inquiry card.

BYTE October 1981 125

Software Protectionin the United Kingdom

The first conference on softwareprotection in the United Kingdomstarted with a joke and ended with ajoke. In between, there was little tolaugh about. In opening the con-ference, Alistair Kelman, a leadingsoftware copyright lawyer, told anold music-hall joke about anEnglishman who asked an Irishmanhow to get to County Derry. TheIrishman replied, "If I wanted to getto County Derry, I wouldn't startfrom here." In other words, Kelmansuggested, if we had a choice in thematter of software protection, wewould not set out from the point atwhich we find ourselves: ensnared bya tangled and thorny copyright lawwhose concepts spring from the dayswhen the computer was little morethan a fancy abacus in the mind ofCharles Babbage.

The conference's closing joke camefrom retired software dealer and in-dustry pundit Julian Allason, whoproposed a "final solution" to thepiracy problem: give the pirates freerein! Allason told how the Americansoftware house OEM is offering a"nonexclusive" licensing deal. For$460, OEM sells a complete line ofprograms, which the purchaser candispose of as he wishes—for his ownuse, for copying, or for modification

Martin HaymanScience Writers80 Paxton RdLondon W4 2QX England

and resale. According to Allason,OEM intends its programs as "blue-prints" that the purchaser can modifyto meet his needs. But even so, an un-named mail-order firm has alreadypirated OEM's products, offering thecomplete OEM line for a mere $260.Held in March at the WaldorfHotel in London, the Computer Soft-ware Protection Conference was sub-titled "How to Beat the Pirates." Theconference offered many suggestionson how to deal with the worldwideproblem now reaching epidemic pro-portions in the UK. But the generalconclusion was that the pirates can bebeaten only by spending lots of timeand money and retaining a knowl-edgeable lawyer from the outset.

The Backup Problem

Software theft has only recentlybecome a problem in the UK. Hard-ware releases usually reach the UKabout a year after introduction in theUnited States. In the one-year inter-val, Americans do a great deal ofsoftware development for the newmachine. Because a question alwaysexists about how and by whom theAmerican software will be brought tothe UK, the situation seems to offergreat possibilities for software

thieves.

Perhaps we should be surprisedthat VisiCalc, the world's best-sellingprogram, was not copied here untillate in 1980. VisiCalc retails in the UKat £125 ($290) and is distributed byApplied Computer Techniques(ACT) of Birmingham, the same firmthat sells the Commodore PET,Britain's best-selling microcomputer.In December 1980, ACT discoveredthat a mail-order firm run by DavidBolton was marketing what it called a"backup disk" for VisiCalc. The"backup disk" didn't contain a copyof VisiCalc but was preformatted in away that enabled the user to defeatVisiCalc's protection routines andmake a backup copy of the originaldisk from ACT. Bolton's backupdisks sold like hotcakes, partlybecause ACT itself still will not give aregistered user of VisiCalc a backupcopy.

ACT promptly retained AlistairKelman to apply to the High Courtfor an injunction to stop Bolton fromselling the "backup disk," which ACTclaimed was effectively a copy or aninvitation to copy, and hence abreach of copyright relating to "ar-tistic or literary works." After re-quiring ACT to get US suppliers Per-sonal Software and Software Arts as

126 October 1981 © BYTE Publications Inc

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co-applicants in the injunction, thecourt found no reason to stop Boltonfrom selling his "backup disk."

Instead, the court simply passed amotion requiring Bolton to record allsales of the disk until some future daywhen the matter would come to trial.In the event of a trial, the motionwould become the basis of any legalaward for compensation. But even ifBolton paid up, the cost of recoverywould far outweigh the damagesthemselves. The legal process is ex-tremely slow in the UK, and thebackup disk is still being sold. Fur-thermore, practice at the UK Bar for-bids a lawyer from taking a case on aspeculative basis. Counsel's fee forpleading is payable whether or notdamages are recoverd. This makes"test cases" such as this one a ratherQuixotic exercise.

Oblique Threat

In the Bolton case, an apparent at-tempt to persuade Bolton to desistmay have undermined the position ofthe plaintiffs. On the morning of hisappearance in court, Bolton receivedby mail a trade-newspaper clippingdescribing the somewhat similar caseof Vincent Cohen. London police ar-rested Cohen in connection with thealleged theft and dishonest handlingof source code belonging to theAmerican firm Graham-Dorian Soft-ware. Detectives interviewed Cohenand were thought to be considering acharge of conspiracy. (By a quirk ofEnglish law, one need not actuallyconspire to do anything illegal inorder to be charged with conspir-acy.)

The Cohen case has now been set-tled out of court, but the case wasvery much alive when someone sentBolton the clipping with the word"arrested" underlined. Clearly thesender of the clipping knew the dateof Bolton's hearing, and that suggeststhe sender was an interested party. AsAlistair Kelman pointed out, if ajudge learned that a plaintiff had in-dulged in this sort of oblique threat,the plaintiff's case could only suffer.

Cohen, incidentally, appeared atthe piracy conference lookingunabashed.

To Be a Pirate

Against this background, JulianAllason's opening remarks are under-standable. "If I were to start again inthe software business," he said, "Iwould be a pirate. It's the quickestway to make money with the leastrisk that there is in Britain today. Iwould buy a wide range of programs,copy them and resell them by mail-order. Then if things went well,which they would, I would get boldand make the programs available todealers. If the programs were so wellknown as to be obviously recognized,then I would describe them as'backup copies.' "

Although Allason said additionalprecautions would probably be un-necessary, the aspiring pirate couldput aside any fears by followingAmerican practice: change a few pro-gram lines, renumber the program,remove the serial numbers, advertiseunder a bland trade name, or buy a"cut-out" license from a companythat has either gone out of business orbought its license from anotherdubious and short-lived company.The result is a "deck of cards" inwhich each company must be sued inturn. This wrinkle is a recent migrantto the UK, first making its appearancein the case of a backwoods outfitcalled Kansas City Systems.

Level IV, Anyone?

Despite its name, Kansas CitySystems is literally a backwoodsoperation. Its premises are a shack ina forest near Chesterfield, in thenorth of England. One of the Britishdistributors of Level III BASIC and anassociated monitor, the Eastbournesoftware house A J Harding (Moli-merx), took Kansas City Systems tocourt for pirating Level III and resell-ing it as Level IV. Kansas CitySystems' chief, Tom Crossley, arguedthat he had bought the software fromone Sorrell B Chapman, whom hemet at a microcomputer show in Bri-tain in 1979. According to Crossley,Chapman claimed to be legitimatelyselling the software on behalf of thenow defunct GRT Corporation.

Clearly there is no way for an

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English court to test the validity ofthe American "cut-out" license, but inthis instance the plaintiffs won aqualified victory. Using an unusuallegal instrument called the AntonPillar order, the plaintiffs got hold ofdisks, documentation, and corres-pondence belonging to Kansas CitySystems. The Anton Pillar order em-powers the plaintiff's legal representa-tive to act as an officer of the court incases of suspected copyright infringe-ment. The plaintiff's lawyer can re-quire the defendant, without notice,to open his premises to a search andto let the plaintiff's representativetake away any relevant documents. Ifthe defendant refuses, he is in con-tempt of court.

The Knock at Night

Will the Anton Pillar order play animportant role in the control of soft-ware piracy in the UK? Will piratesfear the knock in the middle of thenight? Alistair Kelman calls the An-ton Pillar order a "judicialinvention," noting that Parliamenthas never debated this unusual provi-sion for search and seizure. But theAnton Pillar order has already beenused several hundred times.

Although most commonly appliedin piracy cases involving phonographrecords and music tapes, the orderwas first invoked in a case of com-puter piracy. Its namesake, AntonPillar, was a German manufacturer ofan emulator utility for IBM equip-ment. British distributors of the utili-ty, however, started making unli-censed copies and selling them at cutrates. When Pillar found out, hesought an injunction to stop thepirates, and he successfully arguedthat the evidence needed to prove in-fringement could only be seized by asearch that took the offenders by sur-prise.

Kelman noted that at the top end ofthe market, much business can be lostthrough organized software piracy."There is now a risk from organizedcrime—the big sharks who will be areal menace as the market develops,"he warned. But so far, little evidenceof organized crime involvement hassurfaced. In typical piracy cases,

130 October 1981 © BYTE Publications Inc

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dealers supply a "complimentary"copy of one disk instead of a discounton another; or a service engineer "justhappens to have" a word-processorprogram that he can get the customerfor a cash discount—say of 90 per-cent.

Only Amateurs

Home copiers, as distinguishedfrom professional bootleggers, drewsharp words from Allason. Claimingthat amateurs account for 99 percentof illicitly copied programs, Allasonrevealed the results of a confidentialsurvey of PET users in the UK. Forevery program bought from alegitimate source, Allason found, twoand a half copies were made withoutpermission. The UK trade paperComputer Weekly confirms Allason'sfigures. Commodore says its softwarecassette market has slumped to only40 percent of what it was a year ago.Even with many PET users changingto disk, such a decline in cassette salesputs an intolerable strain on themarket.

Is copying in the home less per-nicious than professional bootleg-ging? From the amateur's point ofview, illicit copying might seem agood thing. Certainly the surround-ings are innocent enough; this sort ofcopying takes place mainly amongfriends, at schools, and in usergroups.

But amateurs confront softwarepublishers with a dilemma: ifpublishers take no steps to protecttheir programs, making a copybecomes the easiest thing in theworld. On the other hand, ifpublishers use protection routines,making a copy is for many amateursthe most enjoyable thing in theworld. Unlike semiprofessional usersof software, amateurs have both thetime and the enthusiasm needed todefeat protective measures. PeterLaurie, editor of Practical Com-puting, confirmed Allason's view bysaying, "Any intelligent teenager willmake it (overcoming copy-protectionmeasures) his first task of the day."

The case of Microchess shows howseverely amateur copying candamage software sales. Before the In-

ternational PET Users' Grouppublished a method of copyingMicrochess, the game program hadsold more than 100,000 copies. Afterpublication of the copy method, salesdried up. By contrast, the semi-professional program Wordcraft en-joyed a dramatic increase in saleswhen the protection routine knownas the "Dongle" was incorporated.

The Price of Free Copies

The amateur's own long-term in-terests are actually damaged by copy-ing software at home, according toAllason. As royalties decline, bothauthors and publishers become reluc-tant to publish. Until recently, ACTpublished 200 titles; its list has nowdwindled to 20. The company nolonger finds it worthwhile to publish,document, and support a long list ofmarginal sellers. Instead, ACT leavesprograms with a small market tosmaller firms that skimp on documen-tation and support, or to bootleggerswho provide no support and whowould never consider providingdocumentation. Because documenta-tion is clearly a written work, it issubject to the provisions of theCopyright Act.

Allason named some programswhose publication stands in jeopardybecause of pervasive software piracy.Among them are a financial modelingprogram called Nebula, produced at acost of $600,000; Micromodeler,which was to have sold for $900; andDr Michael Brinson's elegant anduseful AC Circuit Analysis, with-drawn from the marketplace.

In brief, Allason said amateurpiracy will have five consequences forthe average software buyer. It willreduce the range of softwareavailable, raise prices, and makecompanies reluctant to invest in soft-ware development. He said piracyalso leads to lack of support andmaintenance, and discouragesdevelopment of software by cottageindustries which cannot afford to goto court to protect their interests.

Allason disagreed with those whoclaim the solution to piracy is toreduce prices paid by consumers. Hecited a survey showing that programs

132 October 1981 © BYTE Publications lnc

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Few Are Innocent

Consultant Ian Litterick ap-proached software piracy with anhonesty that refreshed some and hor-rified others. Stepping up to speak on"Why I Am a Software Thief," Lit-terick asked, "Which of you can say,hand on heart, that you have nevermade a copy, or used oneknowingly7" Fewer than five peopleraised their hands.

Buoyed by this mass confession,Litterick assuaged everyone's guilt byarguing that bootleg copies are in-dispensable for software evaluation.In the hectic and hyped atmosphereof a store, he said, real evaluation isimpossible. Authors of good softwarehave nothing to fear from unauthor-ized copies, according to Litterick. "Ifit's a good package," he claimed,"then there are compelling reasonswhy I should go on to buy it in theconventional way."

Litterick's speech implied that theunseen "customer" actually plays avital role in the development of soft-ware. With the help of the amateurpirate, poor programs are graduallywinnowed out, leaving the kernel—the 100-percent debugged, easy-to-run, and magnificently documentedsoftware—selling for a song. If onlyauthors and publishers would show alittle more gratitude!

A great many amateurs wouldprobably endorse Litterick's secondpoint: a single-disk user must have abackup copy, especially if he has bothdata and program on the one disk.What's more, Litterick said defiantly,what can any of the manufacturers doif the determined thief goes for bit-by-bit copying?

Countermeasures

The conference raised many ideasfor fighting software piracy. Someare new and theoretical, but most arealready familiar to Americans.Allason ran down a list of anti-pirateweapons that he thinks should bebrandished immediately:

• "Megabuck" lawsuits—the cost-attrition weapon.

134

October 1981 © BYTE Publications lnc

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• The embarrassment factor. Perhapssaying "You know that I know" willbe more effective in the UK's smaller,more centralized economy than in theUS.

• Induced dependence, a strategyused by mainframe manufacturerswho claim that only they can givecustomers the documentation andbackup they need.

• Licensing of users, generally con-sidered the most effective weaponagainst piracy.

Laurie believes licensing is the onlyeffective way to combat pirates.Although amateurs are too numerousand energetic to be stopped from

making illicit copies, vendors canstop real pirates by using existing pro-visions of law to secure agreements atthe point of sale. If the supplier'sname is visibly coded in at the begin-ning of a program, and invisiblycoded in elsewhere, there is a legalbasis for enforcing the original licenseagreement. The visible trademarkestablishes a breach of contract; theinvisible, if the illicit copier expungesit, establishes a breach of copyright.When programs are intended forthe mass-market microcomputer,Laurie sees a contradiction in tryingto discourage copying by making theprograms hard to use. Software ismade to be used; in fact, a license

should permit the licensed user tomake the modifications he needs. Ty-ing software to a specific machine orimplementing a turnkey systemwould be self-defeating.

The Case of ChessBall

Alistair Kelman gave the con-ference a detailed and analytic look atthe state of the legal theory of soft-ware protection. In both British andAmerican law, the most desirableform of protection for a computerprogram is a patent, which confers amonopoly on the owner. Unfor-tunately, in the UK the Patent Act of1977 specifically excludes computer

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136 October 1981 © BYTE Publications Inc

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software. But Kelman showed how,in the realm of computers, the ar-tificial distinction between copyrightand patent can make a monkey of thelaw.

Kelman described a game calledChessBall, invented by patent agentPaul Cole. A board game combiningchess and football, ChessBall isplayed by two teams of threeplayers—a Knight, a Queen, and aBishop. The ball is on a grid andreacts to the arrival of a player in oneof the surrounding squares accordingto a complex set of rules. Goalposts

stand where the King and Queen aresituated on a normal chessboard.The object of the game is to score asmany goals as possible in a set period."It is possible to sell ChessBall as aboard game, and it might be possibleto obtain a patent for it," Kelmansaid. "However, it is also possible tosell ChessBall as a tape which couldbe loaded into the domestic micro-computer and played by the family. Itwould further be possible to make aspecial microcomputer where thegame of ChessBall was built into theelectronic circuits. Under the present

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law, the game on tape is not patent-able but the designated micro mightwell be."

These ideas were elaborated uponby Laurie, who advanced the ideathat a "device" is patentable andhence enjoys the protection of patentlaw, which is far more bulletproofthan copyright law.

"Let us suppose," Laurie argued,"that you have a bright, patentableidea and wire together some discretetransistors to make it work. Theresult is certainly a device and can bepatented. Suppose that you take anuncommitted logic array and con-figure it to work like the transistors.Again a device, and patentable. Sup-pose you use a microprocessor con-trolled by a program in ROM (read-only memory). The ROM is physical-ly changed by programming it. Thesame program in EPROM (erasableprogrammable read-only memory) isalso a device, even though the altera-tion to the basic structure is just in thedistribution of charge." If the pro-gram is in dynamic memory and thecharge lasts only a millisecond, it'sstill a device, he said.

By a quirk of the British PatentLaw of 1977, a person can commit"contributory infringement" of a pat-ent if he helps someone else infringethe patent by, for example, providinginstructions about how to do it. Bythis means, Laurie argued, it istheoretically possible to catch thesoftware pirate. The pirate may, hesaid, be giving "instructions" in theform of software which, once loaded,becomes a patent infringement underthe terms of the Act. This approachmay or may not work; certainlynobody in the UK has had the nerveto put it to the test.

New Concepts

In the process of trying to overhaulthe Copyright Act of 1956, Kelmanhas suggested some new concepts thatmay help clarify legal thinking aboutthe intellectual property called soft-ware. One important concept is thatof "transitory reproduction."

According to Kelman, a transitoryreproduction occurs when, for exam-ple, a program is read into memory

138 October 1981 © BYTE Publications Inc

and used to perform a particular task.Although the program itself may be acopyright work, no blame is attachedto using and reproducing the programfor the brief period of its appearanceon the video display terminal. Nordoes the use of the copyright workdilute in any way the copyright ofany material which the transitorilyreproduced program has processed.

Kelman has proposed a new con-cept called "transmutation" todescribe any computing whose finaleffect is to steal one person's programand render it in another form. Hedefines the term as the automatic con-version of a source work into an ob-ject code by electronic, mechanical,or similar techniques. Transmutationis intended to cover such familiarwords as "compile," "assemble," and"interpret," which already havespecific meanings in law and com-puter science.

British courts already have gropedwith the concept of transmutation,but the current copyright law hasshown itself unable to cope with thenew concept. A notable instance is arecent case in which Sinclair Elec-tronics sought an injunction againstCompshop, which Sinclair allegedhad copied the design of Sinclair'sZX80 pocket computer kit and in-troduced the copy in the US. Kelmanbemoaned Justice Megarry's positionthat information held in ROM couldnot be copyright "because he couldn'tsee it." Kelman asked whether therights to the Justice's own work,Manual of Real Property, woulddisintegrate if the manual wereentered into the memory of a com-puter as a code, and then accessed bysomeone asking questions in "com-puter language."

International Complications

Although Kelman's concept oftransmutation has found some favorwith European lawmakers trying todraft a harmonized copyright law forEurope in the 1980s, important dif-ferences exist between Continentaland Anglo-Saxon laws on intellectualproperty. These differences may com-plicate international software protec-tion. The Continental concept of

"moral right" to intellectual propertyis an example. In the US and the UK,an author sells intellectual property inmuch the same way as he would sell apiece of furniture. The author getsmoney in exchange for rights to theproperty. According to Continentaltradition, however, the author retainsthe right to have his name associatedwith his work, and to stop unauthor-ized versions of his work from ap-pearing, whether or not he has sold,given away, or otherwise disposed ofhis pecuniary rights with respect tothe work.

Will Continental programmers beable to wield the concept of "moralright" in defense of their creations? Ifso, could the Anglo-Saxon world bor-row the concept? Will North Ameri-can and British programmers be ableto defend their rights by pressing theimportant distinction between "tran-sitory reproduction" and "transmuta-tion"? Until these questions areanswered, software authors andpublishers can only hope to enforcelicense agreements signed at the pointof sale. The laws on software piracyare all buckle and no swash. ■

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October 1981 © BYTE Publications Inc 139

Network Tools

Ideas for Intelligent Network Software

Peter B Reintjes

Rte 3 Box 85

Morehead City NC 28557

Some people foresee electronic in-formation as the currency of thefuture: those who have it will use it toget more, and those who don't have itwill be exploited. Actually, moneyprobably will continue to be the cur-rency for years to come, but the com-puter will be the primary tool for con-trolling its flow. The key to this flowlies in computer networks. With theprice of individual computers drop-ping, more people are solving theirproblems with computer networks,rather than with a single large com-puter.

Networks are more than just con-nections between computers. Thephysical connection—be it a twisted-wire pair, phone line, or satellitetransmission—is of little consequencecompared with the software that usesthe connection.

Personal Computer Networks

Most network software devel-opments aim to define protocols withsufficient generality to last a decadeor more. ARPAnet, X25, andEthernet, all primarily computer-to-computer networks, are now thefocus of computer vendors' attention.

But another group of networks usescomputer-human interfaces to pro-vide interactive services. News andmail systems, shopping marts forsoftware releases, and bulletin boardsall fall into this category.

In these networks, informationclearly is not currency but instead thecommodity being paid for. (You maybecome painfully aware of this upon

receiving monthly bills from thetelephone company and the "infor-mation utilities.")

As a personal computerist, youhave special needs that should betaken into consideration by the net-working software. Ideally, yourhome computer should become an in-telligent node on the network, mak-ing the network connection processinvisible to you. Under such asystem, your computer can call upthe information service at night,when rates are lowest and the net-work response time is probably at itsbest.

An intelligent node system hasanother valuable application: a set offiles on one computer can be trans-ferred automatically to another nodeon the system. Each night when thenetwork is activated, system A callssystem B to determine which one hasthe latest version of each file. The up-dated file is then copied over the out-dated one. You can spend all day Fri-day editing your resume on system Aat work or school, then get up Satur-day morning to find the edited ver-sion in your home computer's file,ready for further use or revision. Asimilar procedure could be used tosend revisions of operating systemsand even the network programsthemselves. The command to activatethe network can be executed at anytime if a transaction is required beforethe usual late-night activation.

An Intelligent Node Program

With the needs of the personal

computerist in mind, I have designeda set of modules that provide a basisfor networking. I tried to make themodules very general, as well as com-pact and efficient enough for use in anactual networking system. In anyevent, the modules should proveuseful in trying out new protocolsand adapting quickly to different net-work interfaces.

Designing a network from theground up provides the advantages ofcontrol over the planning and regula-tion of protocols and transactions.James Martin's book SystemsAnalysis for Telecommunications isrecommended to anyone interested indesigning a network. Anothervaluable book is Software Tools byKernighan and Plaugher, from whomI have borrowed the idea of pre-senting modular programs as a set oftools. In this case the tools are fordeveloping a network system.

Desirable as it may be in someways, designing your own networkcreates the immediate problem of in-terfacing with all other informationservices. For the microcomputerowner, a more realistic goal would bedesigning a general-purpose interfaceto converse with other machines onthe network, and then designing alocal protocol to "ride on top" of theinterface. The designers of the X25network architecture anticipated thisproblem when they specified X25 inseveral distinct layers. Only thelowest level is in contact with the net-work. The higher levels behave as ifthey were sending and receiving data

140 October 1981 © BYTE Publications Inc

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across the network in a more abstractway.

The lowest (physical) level of anynetwork can be implemented with myproposed networking modules. Theuser level could be fashioned to ap-pear the same as X25 or the ARPA-net.

The following specificationsdescribe software modules needed fora basic network capability. Thesource codes for five of thefunctions—DIALER, PROMPT,CONVERSE, TRANSLUCID, andTRANSACT—are given after thespecifications. These functions can beimplemented in whatever language isavailable, and under any operatingsystem or monitor the user chooses.Once the functions are available, theenvironment will be reasonably in-dependent of the operating system,and future utilities designed for thisenvironment will be easier to install.The functions can make the networkprotocol easier to implement and putthe transaction processing on a highlevel.

WATCHDOG and ALARM

Networking, a real-time process, isslow and has a wide tolerance forspeed fluctuations. But because pro-tocols still must be executed in theproper sequence and in a consistenttime frame, interrupt handling isneeded for timing functions as well asfor input and output.

Many large networking computershave multiprocessing operatingsystems. They can have several tasksrunning at once, trading off centralprocessing unit (CPU) cycles, andeach task can be doing part of the job.The most important tasks are theALARM and WATCHDOG func-tions, and I have included themamong the modules. ALARM tells thesystem when it is time for a transac-tion, or when certain services areavailable on the network. WATCH-DOG watches the network traffic andsteps in if a conversation gets boggeddown in protocol.

In networking, perhaps more thananywhere else, error recovery iscrucial. When two computers are

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talking over a voice-grade line at 4:00in the morning, they could easily getout of step on a bad byte. In this case,you would at least want to make surea telephone connection is broken, andyou probably would like the com-puters to settle their differenceswithout waking someone up or hav-ing to start from scratch the nextnight. This level of error recoverymay sound formidable, but a fewstrategies can solve most commonproblems while enabling your com-puter to decide when it is hopeless tocontinue trying.

The WATCHDOG and ALARMfunctions can also be implemented onthe typical personal computer systemwithout multiprocessing. A timerwith interrupt capability is required,and a real-time clock with interruptalarms would be best.

Both the WATCHDOG andALARM functions can be im-plemented in the same timer-interruptroutine with a global flag to signifywhether the normal ALARM mode orthe WATCHDOG mode is active. Inusing the ALARM function, a pointerin the AGENDA (a file specifying thetransactions that need to be per-formed) shows what the next activityis and when it is scheduled. The timeris then set for activation, and the pro-cess goes into a wait state. When theinterrupt occurs, the interrupthandler notes that it is in the alarmmode and jumps to a routine whichstarts up the desired activity.

If you are starting a process whichmay get hung (meaning you may waitforever for a transaction to be com-pleted), set the TIMER function toWATCHDOG, start the timer andstart the process. If the process is notfinished before the timer causes an in-terrupt, the handler will see that itwas activated as a WATCHDOG,and it will look around for an in-complete transaction. Then it canclean up the failed action, closing orremoving any files the transactionused and incrementing a counter tokeep track of the number of failures.If this counter exceeds a certainthreshold, the transaction will beremoved from the agenda and

142 October 1981 © BYTE Publications Inc

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JUST LAUNCHED!VOYAGE OF THE VALKYRIE

BY LEO CHRISTOPHERSON

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The ancient Norse lords bravely sailed their ships across new waters in search of

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the pilot of the attack ship Valkyrie. Your mission: to wrestle the island Fugloy

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The flow of control when the timerinterrupt occurs is shown in figure 1.The timer-interrupt handler providesthe synchronization. When thesystem has finished its nightly trans-actions, it may print a status reportsimilar to the one in figure 2.

TIMER

Set the timer to wait for a specifiedtime. It can be set in seconds,minutes, or until an actual hour if areal-time clock is available. When thetime is up, the interrupt routine will

be activated, either in the WATCH-DOG or ALARM mode.

DIALER

DIALER is a procedure for dialingthe phone number of the remote com-puter. This software (see listing 1),plus a simple relay driven from anoutput port, can substitute for an ex-pensive auto-dialer. Becausetelephone service supports pulse dial-ing even in areas with Touch Toneservice, this procedure is a very cost-effective way for your computer tomake phone calls. The phone number

TIMER GOES OFF:

CLEAN UP.

PUT FAILED TASK

BACK ON AGENDA

INCREASE NUMBER OF TRIESIF TRIES > T, TASKFAILED. LOG IT ANDREMOVE FROM AGENDA

SET TIMER.GO TOSLEEP

ACTIVATENETWORK

WAKEUP CALL.PRINT STATISTICS.ENTER INTERACTIVE MODE.

LOG DATA

FROM

SENSORS

-J

Figure 1: Flow of control when the timer goes off.

is represented as an array of 20characters. The only valid charactersare the digits 0 through 9 and a dash(—). The dash is interpreted as apause in the dialing sequence.

PROMPT

This routine, shown in listing 2, iscalled with a sample prompt stringand a pointer to a buffer of text. Itdetermines whether the promptoccurs in the text, returns the offsetinto the buffer, or returns a negativenumber if the prompt is not found.

When you are conversing with aremote host system, a prompt fromthe host signals that the system iswaiting for a command. On IBM'sOS-360, it might be the word READYand a new line; on the UNIXoperating system it is usually a per-cent sign followed by a space. Yoursystem needs to recognize the promptcoming from the remote system andrespond to it appropriately. Thisrecognition is especially useful duringthe log-on procedure, when thesystem may have a status message ofindeterminate length.

An alternate scheme for recogniz-ing a prompt in the input stream isdetailed in the TRANSACT pro-cedure.

CONVERSE

The CONVERSE function in listing3 attempts to carry on the dialog con-

Text continued on page 154

Good MorningNocturnal Network Summary 8:02 May 19, 1981

Successful Transactions Time on Time off

#

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MAIL; NEWS

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2:18

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FILE x from remote

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2:40

777-7777

2

FILE y to remote

MAIL; NEWS

NEWS

3:10

3:20

888-8888

i

1

uccessful Transactions

FILE n to remote

3:45

3:50

Hi-mi

4

MAIL

3:55

4:10

222-2222

4

Figure 2: A sample report summarizing the activities of the preceding night.

144 October 1981 © BYTE Publications Inc

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Listing 1: The module for dialing a telephone number using a simple relay to create pulses.

module dialer;

(* *)

(* Dialer is a function which alternately opens and closes *)

(* a relay on a phone's hook switch to 'dial' the number of *)

(* the remote computer. *)

(* *)

(* Copyright 1981 by Peter Reintjes *)

(* *)

type

const

phone_number = ARRAY [1..20] OF CHAR;

HMASK = 100;

PAUSE = 10000;

HI_DC = 400;

LO_DC = 600;

var

i, j, n: INTEGER;

c : CHAR;

exit : BOOLEAN;

(* bit in register for relay *)

(* constant for pause *)

(* These two numbers set the *)

(* duty-cycle of the relay *)

external assembly procedure relay( data : INTEGER);

procedure high;var

i : integer;begin

(* relay is an assembly language routine to set the *)(* output port for the dialer to the value HMASK *)relay(HMASK); (* turn bit on *)

for i:=0 to HI_DC do ; (* relay on *)end;

procedure low;var

i : integer;begin

relay(-HMASK-1); (* this inverts HMASK *)for i:=0 to LO_DC do ; (* relay off *)end;

entry procedure dialer (telenum: phone_number);

(* telenum is at most 20 chars, terminated with a null *)

begin (* begin dialer *)

(* null char is after the last digit in the array *)

for i:=l to 20 do beginc := telenum[i];case c of

Listing 1 continued on page 150146 October 1981 © BYTE Publications Inc

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Listing 1 continued:

'<0>': exit := true; (* null character *)

,l'f'2,,,3,rl4,f'5',•6','7','8','9','0': begin(* integer value of digit *) n := ord(c) - 48;

if (n=0) then n:=10;for j:=0 to n do begin

high;(* toggle relay *) low;

end;end;

*-': for j:=l to PAUSE do; (*pause*)

otherwise begin

writelnt'error: bad digit ',c);exit := true;end;end; (* end of case *)if (exit) then exitloop;end;end;

Listing 2: The module to recognize a prompt from the host computer and take appropriate action.

module prompt;

(***************************************************************)

(* Prompt is a function which searches a text buffer for an *)

(* occurrence of the 'prompt' a string specified in the array *) -

(* pmt[]. It is called prompt because it will most often be *)

(* used to wade through extraneous system chatter to determine *)

(* if the remote system came back with a 'prompt'. *)

(* *)

(* Copyright 1981 by Peter Reintjes *)

(* *)

(♦A*************************************************************)

type

buffer = ARRAY [0..2047] OF CHAR;

buf = Sbuffer;

prom = STRING 50;

entry function prompt(pmt: prom; bptr: buf; off,len:INTEGER):INTEGER;

var c : CHAR; (* temporary character *)ifp : INTEGER;

lpmt : INTEGERfound : BOOLEAN

(* boolean true when prompt is matched *)

begin

found := false;

lpmt := length(pmt);

p := 0; (* pointer in text buffer *)

c := bptr@tp+off]; (* c gets first character *)

while( NOT(found) AND (p<len-lpmt) ) do begin

Listing 2 continued on page 154

150 October 1981 © BYTE Publications Inc

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Listing 2 continued:

i := 1;

while( (c=pmt<<i>>) AND (i<=lpmt) ) do begin

i := i + 1;

P := p + 1;

c := bptr@tp+off];

end;(* while c matches next char in pmt*)

(* if entire prompt recognized, i will equal lpmt+1 *)(* if part of pmt was seen, we must move p back *)

if ( i <= lpmt ) then begin

p := p - (i-1);end;

end;

if (i = lpmt+1) then found := true;

if found, offset of prompt into text buffer passed *)

if found then prompt := pelse prompt := -1;

end;

Text continued from page 144:

tained in the file SCRIPT. For in-stance, SCRIPT may contain thedialog necessary to log on to theremote system. This function will beinvoked after the number has beendialed and the remote system hasanswered. If CONVERSE does notget the response it expects at anypoint in the conversation, it can dropback to an earlier part of the conver-sation and try to pick up the thread.However, if it continues to find errorsand can't get through, it will give upand tell the transaction processor totry again later.

CONVERSE allows the system tolog on to interactive services designedfor a human interface, and to give thelocal system access to these serviceswithout operator intervention. It alsolets you test new protocols by pro-viding a table-driven protocolhandler.

If the remote system has a responseused to indicate an incorrect sequence(for example, INCORRECT USERNAME-TRY AGAIN), thatresponse should be included in themodel of a normal dialog. Giving theremote system an empty line instead

of your user name might be one occa-sion for generating the response.Having this message in your dialogwill give you a recovery point. Ifsomething happens later in the dialogand the system responds with IN-CORRECT USER NAME—TRYAGAIN, you will be able to pick upthe conversation at the appropriatepoint.

CLEANUP

If the WATCHDOG wakes up andsees that a specified transaction wasactive, it calls the CLEANUP functionto shut it down. If the number of triesfor this transaction exceeds a prede-termined limit, it is taken off theAGENDA.

TRANSLUCID

This is a shell, or command-line,program which interacts with the userat the keyboard. The primary func-tion of TRANSLUCID, shown inlisting 4, is to make the local com-puter look like a terminal, passing in-formation from the user's keyboardto the network and sending the datafrom the network to the local videodisplay or printer. A secondary, and

equally important, function of thisprogram is to redirect the informationflowing through it into a file, or touse files as the source of text to besubstituted for the keyboard. Usingthe "transparent" monitor to conducttransactions manually will show youthe dialogs which must take place be-tween the computers.

The GETC and PUTC functionshandle character input and outputfrom the user terminal or files desig-nated by the redirection commands.GETREMOTE and PUTREMOTEserve the same function on the net-work (modem) side. The first param-eter to these routines specifies thechannel over which the data is re-ceived or sent. The channels in my ex-amples are the terminal input(STDIN), the output channel to theterminal screen (STDOUT), the out-put to the modem (NETOUT) and thereturn data from the modem(NETIN). All other channels in theprograms are to files on the localsystem.

The second parameter is the char-acter variable, and the third (GETfunctions only) is the WAIT/

Text continued on page 163

154 October 1981 © BYTE Publications Inc

Listing 3: The input/output module, CONVERSE.

module converse;

(* *)

(* Converse is a function which alternately transmits lines of *)

(* text and receives them from the remote unit. It monitors this *)

(* conversation as it proceeds, attempting to recover if it *)

(* gets out of step. It then returns 0 if the conversation was *)

(* successful and a -1 if it failed. *)

(* *)

(* Copyright 1981 by Peter Reintjes *)

(* *)

external procedure putremote ( c : CHAR );

external function getremote ( var c : CHAR; wflag : BOOLEAN ):INTEGER;

entry function converse(fname: STRING 20) :INTEGER;

(* fname is a file of text strings terminated by NULL. *)

(* Every other string starting with the first one is *)

(* what the local unit sends, the next line is what we *)

(* expect to get back. The file starts with a NULL and *)

(* is terminated by two or more NULLs. *)

const

NULL =ATTN =HOLD =

waitnowait

1<0>'; (* reference character *)

'<12>'; (* interrupt remote computer *)

100; (* max time delay for each *)

(* character from the net *)

true;

false; (* options for getremote call *)

var

c, en

i

errors

error

done

giveup

CHAR;INTEGER;INTEGER;INTEGER;BOOLEAN-BOOLEAN;

procedure recover; (* call this as many times as you want *)

var

reply : STRING 180; (* longest response from remote *)

found : BOOLEAN;

error,i,time : INTEGER;

begin

if ( c <> NULL ) then begin (* error recovery *)errors := errors + 1;

putremote(ATTN); (* get remote's attention *)

reply := '"; (* null string for response *)time := 0; (* wait for the response *)while ( time < HOLD ) do begin

error := getremote(c, nowait);

Listing 3 continued on page 156October 1981 © BYTE Publications Inc 155

Listing 3 continued:

if (error = 0) then begin (* we got one *)

append(reply,c);

time := 0;

end;time := time + 1;end;

(* If we waited long enough, the response is in reply *)

(* if there's no reply then the remote system is dead *)

if (length(reply)=0) then giveup := true;

if (giveup) then exitloop;

(* now we search the file for the system's response *)

reset (infile,fname);

read(infile,c);

found := false;

while ( NOT found AND NOT EOF(infile)) do begin

readdnf ile,c) ; (* read past NULL *)

if EOF(infile) then exitloop; (* being cautious *)

(* read past local part of conversation *)

while ( c <> NULL ) do read(infile,c);

readdnf ile,c) ; (* read past NULL *)

if EOF(infile) then exitloop;

i := 1;

while((i <= length(reply))AND(c = reply<<i>>)) do begin

read(infile,c);

if EOF(infile) then exitloop;

i := i + 1;end;

if EOF(infile) then exitloop;

if((i>length(reply))AND(c=NULL))then found := true;while ( c <> NULL ) do read(infile,c);if EOF(infile) then exitloop;end;

if ((cONULL) OR EOF (inf ile) OR (errors>10) ) then giveup := true;end;end; (* end of error recovery *)

(■* Main procedure CONVERSE *)

begin

errors := 0; (* keep track of error recovery attempts *)done := false; (* we've only just begun *)

reset(infile, fname); (* open script file *)

read(infile,c);

while ( NOT EOF(infile) AND NOT done ) do beginwhile( c <> NULL ) do beginwrite(netout,c);read(infile,c);end;

read(infile,c) ;

while (c <> NULL) do begin

r ead ( inf il e , C ) ; Listing 3 continued on page 158

156 October 1981 © BYTE Publications Inc

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Listing 3 continued:

i := 0;

while ( i < HOLD ) do begin

error := getremote(en, nowait);

if ( error = 0 ) then i := HOLD;

i := i + 1;end;

if ( c <> en ) then exitloop;end;

(* c should now be at the NULL before the local *)(* system's next statement. *)

(* If c <> NULL at this point then there was an error *)

(* try to pick up conversation *)while ((c <> NULL)AND(NOT giveup)) do recover;

if (NOT giveup) then beginread(infile,c);

if ( c = NULL ) then done := true; (* two NULLs in a row *)end;

end; (* conversation complete *)

if (done) then converse := 0 (* worked *)else converse := -1; (* failed *)end;

Listing 4: The command processor "shell" program, TRANSLUCID.program TRANSLUCID(input,output);const

ENDOF

=

-1;

NL

=

'<012>';

ESC

=

•<176>';

wait

=

true;

nowait

=

false;

type

cfile = FILE OF CHAR;var

network: TEXT; (* Fake network data source *)

netout : TEXT; (* Fake network data sink *)

auxfile: TEXT; (* One file may be opened for aux output *)

(* Up to 9 files may be opened for *)(* input. *)

macfile

level

done

c

error

aux,app

fname

ARRAY CO..9] OF cfile; (* array of file descriptors *)

INTEGER;

BOOLEAN;

CHAR;

INTEGER; (* error flag back from get and put calls *)

BOOLEAN; (* true if we have an auxiliary file open *)

STRING 20; (* Filename for rewrite or reset calls *)

external function getc(fdesc : FILE OF TEXT;

var c :CHAR;wflag :BOOLEAN) : INTEGER;

external procedure putc( fdesc: FILE OF TEXT; c :CHAR);

Listing 4 continued on page 160158 October 1981 © BYTE Publications Inc

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Listing 4 continued:

function fgetc(var c :CHAR) :INTEGER;

(* file-get keeps track of the multiple inputs *)

(* like the include facility of most languages *)begin

read(macfile[level],c);

if(EOF(macfile[level])) then fgetc := ENDOF

else fgetc := 0;end;

function getlocaKvar c : CHAR; wflag :BOOLEAN) : INTEGER;begin

while (levelOO) do

if (fgetc(c)=ENDOF) then level := level -1;if (level=0) then error := getc(stdin,c,wflag);if (EOF(input)) then getlocal := ENDOFelse getlocal -.= 0;end;

procedure putlocaKc : CHAR);begin

if (aux) then

write(auxfile,c); (* data to auxiliary file *)putc(stdout,c); (* data to terminal screen *)

end;

function getremote(var c :CHAR; wflag rBOOLEAN) :INTEGER;begin

if (wait) then read(netinfc)

else getc(netin,c,wflag);if (EOF(netin)) then getremote := ENDOFelse getremote := 0;end;

procedure putremote( c :CHAR);begin

write(netout,c);end;

begin

level := 0; (* level counter for redirected input *)

while (NOT done) do begin

error := getlocal(c,nowait);if (error <> ENDOF) then begin

if( c=ESC) then begin (* enter command mode *)error := getlocal(c,wait);case c of

ESC: putremote(c); (* pass special character *)

(* take input from *) '<': begin (* increase macro level *)(* a new file *) fname := •';

error := getlocal(c,wait);(* get filename into fname *) while (cONL) do begin

error := getlocal(c,wait);append(fname,c);end;

level := level + 1;(* open new file *) reset(macfile[level],fname);

end;

Listing 4 continued on page 163160 October 1981 © BYTE Publications Inc

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Listing 4 continued:

'>': begin (* put output into file *)if (aux) then

writeln('error: file already open.1)else beginaux := true;

error := getlocal(c,wait);if (c = '>') then beginapp := true;

error := getlocal(c,wait);end;fname := '';(* get filename into fname *) while (cONL) do begin

append(fnamefc);error :=getlocal(cfwait);end;if(NOT app) then rewrite (auxfile,fname)else fileappend(auxfile,fname);end;end;

(* open new file or *)(* append to old file *)

begin (* close file opened by > or >> *)

app := false;

aux := false;

close(auxfile);end;

end; (■

(* terminate connectiondone := true;

)

inner case

)

end;end.

end (* end command mode *)else putremote(c);end; (* ENDOF error check blockerror := getremote (c,nowait);if (error = 0) then putlocal(c);(* while *)

around case *)

(* characters from network

(* go unchanged to local

*)*)

Text continued from page 154:NOWAIT directive to control inputflow. If GETC(STDIN,C,NOWAIT)is specified, the function will comeback immediately even if no charac-ter was available from the console.GETC(STDIN,C,WAIT) will waituntil the user produces the neededcharacter before returning. The in-teger returned by the function willshow if a valid character, no charac-ter, or an end-of-file was received.

The internal designs of the GETand PUT functions depend on the sys-tem and are not shown here. Yourown GETC can buffer an entire linefrom the terminal to allow for back-spacing and editing the line before itis sent.

Some of these commands maycause a great deal of data to come

back across the network. Routineswhich manage the system buffers willneed to control the I/O, sending stopand start codes to the network asneeded to prevent buffer overflow.When the input buffer is full, the hostmust send a pause (Control-S) to theremote to stop any more data flowuntil the buffer is emptied. Then itsends a resume (Control-Q) to theremote unit for more data.

The program continually looks fordata going in either direction andpasses it through. The only exceptioncomes when the user types the escapecharacter (represented as ESC), thusactivating the command processor.The command processor stays activeuntil a carriage return is received, in-dicating the end of the command. Thefollowing commands are supported

by my TRANSLUCID module:

• ESC<filename (carriage return).Take input characters from filenameinstead of the console. When all thecharacters in filename have beenread, return control to the console.The sequence ECS < filename (car-riage return) can occur inside a file aswell as from the keyboard. The ver-sion in this article will support tenlevels of nesting and can be easilymodified for any number of levels.

• ESC>filename (carriage return).Send output from the network to thefile specified by filename as well as tothe terminal screen.

• ESC> > filename (carriage re-turn). Append output from the net-work to filename as above.

• ESC | (carriage return). Close out-

Circle 18 on inquiry card.

October 1981 © BYTE Publications Inc 163

put file specified by previous > or> > command. Note that only oneoutput file can be opened at a time.• ESC . Terminate the program. IfTRANSLUCID is used as a proce-dure, this will return to the nexthighest level.

Any character can be used for theESC or escape sequence by changingthe constant declaration at the begin-ning of TRANSLUCID. This charac-ter can be passed to the network bytyping it twice (only one copy getsthrough). I used the character ESC(hexadecimal IB).

TRANSACT

The program to conduct the trans-action is directed by a data structurewhich describes the transaction. Forall transactions, the program willdetermine what is to be done fromthis structure and execute commandson the remote and local system. Itwill move, copy, or delete files acrossthe link. The data structure is shownin figure 3.

The number of data types deter-mines the number of pending transac-tions a system can have. Following isa description of the variables inTRAN_TYPE:

tran_type = RECORD

action : INTEGER;

system_id : INTEGER;

t_packet : file_name;

active : BOOLEAN;END;

var tran_table : ARRAY[20] OF tran_type;

Figure 3: Definition of the transaction table, represented in Pascal.

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procedure in out is begin exception end; return

function in out return; select else end select; loop

accept do end; task body is begin exception end

select accept or delay end select; task is end

package is private end; for use record end record

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• ACTION: one of five ACTIONSsupported for moving files betweensystems and executing commands onthe remote system. These are detailedin the TRANSACT source code.

• SYSTEM ID: an integer identify-ing the remote unit.

• T_PACKET: the name of the filewhich contains the packet. Thepacket consists of commands to thetransaction processor, commands tothe local and remote system, and data(or the names of files containingdata).

• ACTIVE: a flag set if this transac-tion is the currently active one. Theflag is checked by the WATCHDOGtimer to see if a transaction was activeand timed out.

This data structure will be used bythe three main routines: AGENDA,which sets up the transaction;TRANSACT, the transaction pro-cessor which carries out the actualwork; and WATCHDOG.

TRANSACT (see listing 5) needsthe primitive commands — OPEN,CLOSE, DELETE, PRINT, andAPPEND — for each remote systemwith which it will communicate.When the transaction processorwants to read a file on the remote sys-tem, it must look in a file calledCOMMANDS for the command toPRINT a file on that system. Theproper command is extracted fromthis file by specifying which com-mand is desired and the system iden-tifier. The algorithm appears in theprocedure COMMAND of TRANS-ACT.

The execution of an arbitrary com-mand on the remote system ishandled by case five in TRANSACT.This routine uses another scheme forsynchronizing with the prompt.When a character is received from thenetwork, it is put in a string calledCBUFFER. When CBUFFER is thesame length as the expected promptand a new character is received,CBUFFER is sent along to the output,and the new character becomes thefirst one in the buffer. If the networkstops sending characters, the routinewill time out. The last thing in

Text continued on page 174

164 October 1981 © BYTE Publications Ire

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Listing 5: The module that determines the overall behavior of the network node, according to "instructions" contained in a trans-action table data base.

module transact;

(* *)

(* Transact is the transaction processor. Given a record of *)

type

(* a tran_type, it executes the specified transaction.

(* The following actions are possible:

(* 1 move a new file to the remote system

2 copy over a file on the remote system

3 move a new file from the remote system

4 copy over a file from the remote system

5 execute an arbitrary command on the remote system

(*(*(*(*(*(*(*(*(*(*(*

Basic commands executable on remote system are1: OPEN FILE 2: CLOSE FILE 3: DELETE FILE4: PRINT FILE 5: APPEND TO FILE

Copyright 1981 by Peter Reintjes

*)*)*)*)*)*)*)*)*)*)*)*)*)*)

(*************************************************************)

file_nametran_type

= ARRAY [1..20] OF CHAR;

= RECORDactionsystem_idt_packetactiveEND;

INTEGER;INTEGER;file_name;BOOLEAN;

buffer

buf

prom

= ARRAY [0..20471 OF CHAR;= @buffer;= STRING 50;

external function getremote(channel: CHARS;

var c :CHAR;

wflag :BOOLEAN): INTEGER;external procedure prompt( pmt : prom;

bptr: buf;off, len : INTEGER): INTEGER;

const

wait

nowait

TIMEOUT

= true;= false;= 500;

var

if jf nc

cbuffertime, errorexitfailed

command_filetranlocalname,remotenametempname, newname

INTEGER;CHAR ;

STRING 100;INTEGER;BOOLEAN-BOOLEAN;FILE OF CHAR;tran_type;file_name;file_name;

function command( system, cmd : INTEGER) : STRING 100;

var

Listing 5 continued on page 168

166 October 1981 © BYTE Publications Inc

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Listing 5 continued:

i, n : INTEGER;cstring : STRING 100;

begin

(* The file contains the system name and five commands *)

(* for each system. If we want the third command for the *)

(* fourth system we need to get the 22nd line of the file *)

(* ( system # - 1 ) * 6 + command # + 1 *)

n := (system - 1) * 6 + cmd + 1 ;

for i := 1 to n do read(command_file, cstring);command := cstring;end;

(************** MOVERL *************************)(* move a file from the remote system to local *)

function moverK r_namef l_name :file_name ): INTEGER;

var

If : FILE OF CHAR;result : INTEGER;

begin

rewrite(Iffl_name); (* create local file *)

(* get command to print a file from the remote *)(* write out the command followed by the filename *)write(network, command, r_name);

while ( time < TIMEOUT ) do begin

error := getremote(c,nowait);

if (error = 0) then time := 0;

write (If,c);end;

result := prompt(pmt,bufptr,offset-length(pmt),length);(* the prompt should be the last thing in the buffer *)if ( result = offset + length ) then moverl := 0else moverl := -1;end;

(****************** MOVELR *************************)(* move a file from the local system to the remote *)

function movelr( l_name, r_name :file_name; sid rINTEGER): INTEGER;

var

cstring : STRING 100;

If : FILE OF CHAR;

result : INTEGER;

begin

reset(If,l_name); (* open local file *)

(* get command for opening a file on remote *)cstring := command(sid,1);write(network, cstring, r_name);

Listing 5 continued on page 170

168 Octobtr 1981 © BYTE Publications Inc

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Listing 5 continued:

while (NOT EOF(If)) do beginreaddf,c);write(netout,c);end;(* get command for closing file on remote *)cstring := command(sid,2);write (network,cstring);

(* after network has settled, check for a normal system prompt *)(* Note we haven't read characters from the input buffer yet *)(* These are global variables. *)

result := prompt(pmt,bufptr,off,len);

(* the prompt should be the last thing in the buffer *)if ( result = off + len ) then movelr := 0else movelr := -1;end;

entry function transact (var transaction:tran_type):INTEGER;

begin

reset(command_file,•commands');

with transaction do beginactive := true;reset(packet, t_packet); (* open instruction file *)

case action of

1: begin (* move a new file to remote *)

read(packet,localname); (* name of local file *)read(packet,remotename);(* name of file on remote *)error := movelr(localname,remotename);if (error <> 0) then begin

rem_delete(remotename);

failed := true;

end;end;

2: begin (* copy already existing file to remote *)

read(packet,localname); (* name of local file *)

read(packet,remotename);(* name of file on remote *)

tempname := remotename;

append(tempname,'.temp');

error := movelr(localname,tempname,system_id);

if (error = 0) then begin

rem_delete(remotename);rem_rename(tempname,remotename);endelse begin

rem_delete(tempname);failed := true;end;end;

Listing 5 continued on page 172

170 October 1981 © BYTE Publications Inc

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Listing 5 continued:

3: begin (* move a new file from remote *)

read(packet,newname); (* name of local file *)read(packet,remotename);(* name of file on remote *)error := moverl(remotename,newname,system_id);if (error <> 0) then begin

delete (newname);

failed := true;

end;end;

4: begin (* copy over local file from remote *)

read(packet,localname); (* name of local file *)read(packet,remotename);(* name of file on remote *)tempname := localname ;append(tempname,■.temp1);error := moverl(remotename,tempname);if (error = 0) then begindelete(localname);rename(tempname,localname);endelse begin

delete(tempname);failed := true;end;end;

5: begin (* execute a command on the remote *)rewrite(outfile,■cmd.temp1);

read(packet,command); (* get command from packet *)write(netout,command); (* write it out to network *)while (time < TIMEOUT) do begin

error := getremote(c,nowait);if (error = 0) then begin

time := 0; (* reset clock *)if (length(cbuffer)=length(pmt)) then begin(* we buffer a string *) write(outfile,cbuffer);(* the length of prompt *) append(cbuffer,c);

end;(* do we see the prompt?*)

if (cbuffer=pmt) then failed := false

else failed := true;endelse time := time + 1;

end;

(* Timed out in the middle of the transfer *)

if (failed) then transact := -1(* If the last thing we saw was the prompt *)(* then it worked ok. *)

else transact := 0;

end; (* of case 5 *)end (* of case *)

end;

172 October 1981 © BYTE Publications Inc

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BYTE October 1981

173

Text continued from page 164:

CBUFFER after the routine times outshould be the prompt from the systemindicating that the operation is com-plete. You do not usually want theprompt passed along to the outputfile because it is not really part of thenetwork's response to your com-mand.

Possible Enhancements

Several other functions may beneeded on the local processor, includ-ing:

• Monitor space usage on the localsystem, and terminate network ac-tivity if the local storage is dwindling.

• Buffer input and output to keeptrack of data moving in all directionsand control its flow. The goal is toavoid any loss of data because ofspeed differential or overflow in theinterface.

• Archive data to keep track of thelarge amount of data (and storage)available on the network. You willprobably need some form of off-linestorage, either local or out in the net-work. Systems frequently run out offile space a few months after a mail ornews system is installed.

Both the high-level user interfaceand the low-level system interfacehave been sketched briefly here.These are user- and system-dependentand therefore not portable, but theywill help you develop a protocol-freenetwork on most systems.

Some preprocessing of files can cutdown on the network interaction

time. It is important to order the

transactions by SYSTEM ID so that

all transactions for a given systemwill be made on the same phone call.If there is no system response for thefirst transaction, the others shouldnot be attempted. A Huffman encod-ing can compress text files by as muchas two-thirds and random data by 20to 30 percent. If you are sending largefiles over long distance, this couldmean significant savings.

Making the files self-loading wouldbe an improvement. This can be doneby a separate utility; the actual trans-action processor'could then be muchsimpler than the one I described.

Breaking up large files into stan-dard packet sizes and adding check-sums can reduce the amount of re-transmission due to a dropped bit; theoptimal packet size will depend onthe modem speed and the quality ofthe connection. Other forms of pre-processing can further enhance yournetwork system. With the proper setof tools, these variations can be ex-plored with much less effort.

The problems of conversations be-tween computers are greatly simpli-fied if you install programs on bothsystems which support the same pro-tocol. However, my proposed systemis sufficiently general to be used whenyou have little or no control over thesoftware running on the remote com-puter, and your machine must log onand behave like a human user.

Even if every remote site hascomputer-protocol facilities, they arenot likely to support the same pro-tocol. Modules like the ones I have

presented allow you to build a gener-alized system to converse with allsuch services.

Future Network Developments

Some trends that will make a flexi-ble network philosophy important inthe future already are evident today.

The telephone, for example, willoffer increased bandwidth, possiblyat less expense. Modem-based net-works will be at least as important ashardwired configurations. Greaterprocessing power and storage will beavailable on a network node as morepowerful CPUs and memory systemsare developed. More network ser-vices with a wide variety of protocolswill be available, and we have noreason to be optimistic about standar-dization.

The possibilities for a system nottied to a specific protocol are almostendless. High-level programs can bebuilt for a mail or source manage-ment system. You can write utilitiesthat do everything from answeringyour electronic mail while you'reaway, to synchronizing the systemclock with a weekly call to a com-puter at the National Bureau of Stan-dards.

In addition, the modularity I've en-couraged will allow you to make en-hancements without losing your in-vestment in previous software. Thischaracteristic could mean the dif-ference between a networking systemwhich withstands (or changes tomeet) the test of time, and one thatwill be abandoned in the next genera-tion of hardware and software. ■

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174 October 1981 © BYTE Publications Inc

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A Simple Implementationof Multitasking

Wendell Brown

8 Reynolds St

Oneonta NY 13820

Multitasking software makesmultiuser systems possible and per-mits the division of complex pro-grams into smaller segments. Writingsuch software requires an under-standing of the basic principles ofsynchronization (ie: executing theright program or using the right stackat the right time) and a knowledge ofresource sharing (using such com-puter resources as printers, key-boards, memory, and central process-ing units).

This article explains how to writemultitasking software for micro-processors. I will first discuss thetheory of multitasking, then give asimple example of one of the betterimplementations, called SLEEP(originated by APh TechnologicalConsulting, a firm located inPasadena, California).

Multitasking has many possible applications. A few examples are:handling communications between acomputer and more than one ter-minal; programming devices likethermostats, burglar alarms, andlight controllers; having your com-puter play your favorite adventuregame and regulate room temperatureat the same time; and connecting twoterminals to your computer so thateach can run a different BASIC pro-gram at the same time.

The last example is, of course,timesharing—a well-known and

About the Author

Wendell Brown, a Hughes Aircraft Com-pany Bachelor of Science scholar, is studyingComputer Science at Cornell University.Among his interests are robotics, computergraphics, and speech.

176 October 1981 © BYTE Publications Inc

complex variety of multitasking.

Not all programs can or should usemultitasking, but many applicationsare naturals for this approach.Keyboard polling (watching thekeyboard to see if a key is pressed)and printer driving (telling a printerto do something) can each be writtenas a closed loop, and then, duringexecution, made to seem as if they arerunning simultaneously.

In addition to making your com-puter more versatile and useful,learning to write multitasking soft-ware has other benefits. For onething, it forces you to organize yourprograms. For another, the multitask-ing approach lets you break largeprograms into smaller, moremanageable pieces. You can thenassign the writing to several differentpersons, and the author of one piecewill not need to know how the otherpieces work. Of course, each writermust know the bounds of his or herassignment, and must understand therelationships between the pieces.Dividing programs this way not onlyhelps you complete a large projectfaster, but also simplifies debugging,as it is much easier to debug smallpieces of code than one large pro-gram.

Methods of Multitasking

Though simple in theory, several ofthe methods of achieving multitask-ing are tough to implement. Others

Acknowledgments

/ would like to thank Paul Moster, of CornellUniversity's low-temperature group, for help-ing me write the HPIB software.

can be implemented by means ofstraightforward programming. Let'sexamine a few methods, choose one,and focus on it.

Perhaps the most familiar way tocomplete a series of tasks is to simplyline them up and perform them insuccession. Iri BASIC we could dothis by writing a set of subroutines,and then have a master loop to calleach of the subroutines in turn(sometimes called the "hen-andpiglets" method, see listing 1). Asimilar structure can also be used in amachine-code program.

One problem with the hen-and-piglets method is that subroutines arenot closed; there is no guarantee thatthe piglet will ever run to completion.Thus, each subroutine must have aRETURN statement at the end. Whilethis does not pose a difficulty for sim-ple routines, it can be cumbersome inlarger programs where we mightwant to use a routine written bysomeone else. In that case we mighthave trouble adding the RETURNstatement in the proper place.

Another problem with this methodis that each routine cannot have itsown stack. Although it isn't a prob-lem in BASIC, it can be a big problemin machine code; sometimes a routineneeds its own stack, or the stack istoo short, or we don't want to disturbthe data far up on the stack.

But the hen-and-piglets methoddoes work well for simple programs.The method requires no program-ming overhead, and, furthermore, itis easy to add another routine in theloop. To do so, simply insert a CALLstatement in the control loop where

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the other subroutines have theirCALL statements.

SLEEP

Another way to accomplishmultitasking is a method calledSLEEP. We will focus on this method,in which each routine has a closed

loop and does not return at the end.Instead, the statement CALL SLEEP isinserted anywhere in the closed loopof the routine. In effect, the SLEEProutine replaces the main CALL loopin the hen-and-piglets method.Although implementation is tricky,SLEEP is a unique and useful tool.

Listing 1: A simple BASIC program illustrating the "hen-and-piglets" method of im-plementing multitasking. A master loop starting at line 20 calls each of thesubroutines—Hue}/, Duey, and Luey—in turn.

LIST

10 REM THIS PROGRAM IS AH EXAMPLE TF THE HEN

AND PIGLETS METHOD

20 REM HERE in

THE LOOP

30 OOSUB 100

1*0 GOSUR 200

50 ROSUB 300

60 GOTO 20

100 REM »*•***

HIIEV *******

110 PRINT "H";

*

120 RETURN

200 REM ******

IH1EY »**«***

210 PRINT "n";

220 RETURN

300 REM ******

IUEY *******

310 PRINT "1.";

320 RETURN

READY

RUN

Hni.HDLHnLHnLHnLHDLHDLHnLHnLHnLHDLHt)LHDLHnLHDLHDLHDLHtiLHr)LHDLHnLH

We can use SLEEP to multitask aseries of routines so that they all ap-pear to run at the same time. We'll ex-plore the general idea, then look at aspecific example.

The SLEEP routine essentiallysimulates a complex computedGOTO statement. It first determineswhich program called it, thencalculates which program to jump tonext. The programs are serviced(branched to) in a circular fashion, sothat each program is executed onceevery cycle. The only requirement isthat each program must call SLEEP togive the other programs a chance torun.

When a program calls SLEEP, it is,in effect, giving SLEEP control of theprocessor; SLEEP, in turn, passescontrol on to the next program. If anyof the programs are "time-critical"(ie: must be run within a given timeperiod), then we must be sure that noone routine dominates the processor.Specifically, we must place the CALLSLEEP statement where it will be ex-ecuted often in the loop of each pro-

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No. 225 e1981 Edmund Scientific

gram. Further, we must write a smallprogram (about 30 bytes) to initializeeach program's stack.

Think of each program as havingits own microprocessor. Each pro-gram has an individual stack and iswritten as a closed loop in order toallow continuous operation. All pro-grams share the same memory, whichhas both advantages and disadvan-tages. Programs can pass data amongthemselves by using this sharedmemory as a common data area. Oneprogram can write to a predeterminedmemory byte, while another readsthis byte.

The disadvantage of shared mem-

ory is that sometimes it is convenientfor each program to have its own uni-que memory. For example, if wewanted to time-share a BASIC inorder to run more than one BASICprogram at a time, then we wouldhave to provide enough memory tohold both programs. Since mostBASICs aren't relocatable (having aunique address where they must beloaded and executed), we can holdonly one copy of BASIC in memoryat one time. And since most BASICsuse a unique memory area to store asingle program, we have to use moretricks to make a multiprogramBASIC run. (More on this later.)

Listing 2: SNOOZE, a 6502 assembly-language program showing the SLEEP method ofimplementing multitasking. Three separate programs—Huey, Duey, and Luey—eachcontain a CALL SLEEP statement. The SLEEP routine branches to the programs in acyclical fashion. Each program is executed once every cycle, and all appear to runsimultaneously.

TITLE

"SNOOZE"

/ / / *

/ / /

0 0 / / t* 0 0

• / / r / t i

/ / / / /

0 0 0 0 0 / t

0 0 0

;

THIS S

MPLE EXAMPLE SHOWS

HOW

EASY

IT IS

TO IMPLEMENT A

MULTI-

;TASKED

MACHINE

. THE

THREE

SEPARATE,

INDEPENDENT

PROGRAMS WHICH

APPEAR

;T0

RUN

SIMULTANEOUSLY

ARE:

HUEY,

DUEY. AND

LUEY

HUEY PRINTS A "' "

;THE

TERMINAL,

1UEY A

"d".

AM0 LUEY A

•L".

ZSECT

TTYOUT

= :

$FFEF

JOBS

=

3

STACKLEN

=

20

SPTABLE

BLOCK JOBS

CURJ0B

BLOCK 1

STACKAREA:

BLOCK

STACKLEN

HSTACK

:

BLOCK

STACKLEN

DSTACK

BLOCK

STACKLEN

LSTACK

PSECT

STARTUP:

SEI

CLD

STKINIT:

LDXTXS

#LSB(LSTACK-1)

LDA

♦ MSB(HIEY-l)

PHA

LDA

#LSB(LUEY-1)

PHA

LDA

#LSB(LSTACK-3)

STA

SPTABLE+1

LDX

#LSB(DSTACK-1)

TXS

LDA

#MSB(DUEY-1)

PHA

LDA

f LSB(DUEY-l)

PHA

LDA

»LSB(PSTACK-3)

STA

SPTABLE+2

LDX

» LSB(HSTACK-l)

TXS

LDA

#0

STA

CIIRJOB

;ADDRESS OF TTYOUT ROUTINE

;NUMBER OF JOBS

;LENGTH OF EACH JOB'S STACK

;ARRAY OF STACK ADDRESSES

;NUMBER OF THE CURRENT JOB RUNNING

;EACH JOB HAS ITS OWN STACK

;IN THE 6502, THE STACKS "GROW" UPWARD

;BRANCH HERE TO START EXECUTION;DISABLE INTERRUPTS;CLEAR DECIMAL MODEINITIALIZE LUEY'S STACK

;PLACE LUEY'S ADDRESS ON LUEY'S STACK

INITIALIZE DUEY'S STACK

;PLACE DUEY'S ADDRESS ON DUEY'S STACK

{CURRENT STACK IS HUEY'S STACK;PREPARE TO RUN JOB *0 (HUEY)

»///*//*//**

; THAT IS ALL THAT HAS TO BE DOME TO INITIALIZE THE MACHINE.;N0W SIMPLY JUMP TO JOB #0 (WHICH HAPPENS TO BE HUEY IN THIS EXAMPLE),;AND ALL THREE MACHINES WILL APPARENTLY RUN SIMULTANEOUSLY.

JMP

HUEY

Listing 2 continued on page 182

180 October 1981 © BYTE Publications Inc

E C( u k pnft nt ot Cost

fletunulnted DepreciotiIncorporation Expenses

Less ftrtort tzotionTOTAL ASSETS

TOTAL SHAREHOLDERS' EQUITYTOTAL LIABILITIES + SE

FLOW OF FUNDS REPORT OPTIONS |

a

Inhibit Pi 0 n t h n a m e s

B

Breakdown numbers b y project

c

TotaL monthly expenses''incomes

D

L •. s t cr-.ti.cal. events

E

Subtract incone taxes

F

Store financial statement data

G

Show accounts p a y a b I e •' r e c e i v a b t e

H

Show a 1. 1 operating expense items

I

Show oi l mcone related expenses

J

Show all income items

K

Show all cash flow items

L

Print a single month per page

M

Pause after each month

N

Pause at end of each page

LETTER toggl.es option RETURN pr t r\t£j

(M/22/B3 PCOHPANV Hard Processing Services. Inc.

gs 27

MODEL Medium Growth STARTING 80/S2 ACTUALS

83/83

ID Projtct Nans UNITS EXPENSE INCOME CASH

W/C

MONTH 14, BtpUlbir 19B2

-11 Op Br Eiptmi 1 0 "Fhone"

-72 Rental 1 B "Delivery Van"

le Dantral ovirhud aea? e

-B5 Purchase 2 B "Electric Typ^uriter"

-23 Hire 2 8 -Typist II"

23 Typing Servica 4403 S27S

*3ii Neu Product/Service 'Individually Targated Rtiuxtl"

30 Resume Writing S472 13203

48 Printing 23245 36676

TOTAI

3B177 5S156 45231 62218

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BUSINESS PLANNER is a trademark of Duosoft Corporation.APPLE and Apple Pascal are trademarks of Apple Computer,Incorporated. UCSD Pascal is a trademark of the Regents ofthe University of California.

other costs into an income producingproject.

Projects can be combined togetherin a model to show the net result, or ex-amined independently. By starting pro-jects at different times, you can makecrucial timing decisions.

As your business grows, models maybe combined into larger models. Eachnew venture can be brought under themaster plan. BUSINESS PLANNER cancontinue working for you.

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Listing 2

continued

;AND MOV

THE

THREE PROGRAMS

HIIEY:

i.nA

* t'H"

JSR

TTYOHT

JSR

SLEEP

JHP

HUEY

DUEY:

LDA

!""P"

JSR

TTYOHT

JSR

SLEEP

JHP

miFY

LUEY:

i.nA

#"i"

JSR

TTYOUT

JSP

SLEEP

JHP

I.UEY

SLEEP:

TSX

i.r>Y

CURJOR

STX

SPTABLE,Y

IMY

CPY

* JOBS

BHE

NOZERO

LDY

' 0

MOZERO:

STY

CURJOR

LDX

SPTARLE,Y

TXS

RTS

;PROGRAM HUEY

;PRIHT A "H" AT THE TERMINAL

:PROGRAM DUEY

: PRINT A "P." AT THE TERMINAL

!PROGRAM LUEY

I PR I NT A "L" AT THE TERMINAL

;ROUTIME TO "PUT TO SLEEP" THE;CURRENT JOB, AND "AWAKEN" THE NEXT;JOB. SLEEP CAM BE PLACED ANYWHERE.

;IF REACHED THE LAST JOB, THEN STARTEXECUTING THE FIRST JOB AGAIN

;IF YOU WANT TO SAVE YOUR CPU REGISTERS BEFORE A PROGRAM IS PUT TO SLEEP,;THEN CALL SLEEPR INSTEAD OF SLEEP.

SLEEPR: PUPPHATXAPHATYAPHA

JSR SLEEPPLATAYPLATAXPLAPLPRTS

Example: Using SLEEP

Let's look at the program SNOOZE(see listing 2). Written in 6502assembly language, SNOOZE is asimple example of SLEEP that showshow to multitask the three functionsHuey, Duey, and Luey. SNOOZEcan be broken down into three mainareas: initialization; the sub-programs Huey, Duey, and Luey;and SLEEP.

Although in this example the in-itialization segment is larger than theprogram segment, this is not alwaysthe case. The purpose of initializationis to set up the stack areas for thethree subprograms. We'll follow theinitialization segment from the topdown.

The ZSECT merely tells theassembler to place the following codein page zero (bytes 0 to 255). With the6502 microprocessor, the stack

;SAVE REGISTERS ON STACK

;SLEEP NOW THAT REGISTERS ARE SAVED;AWAKEN. RECALL REGISTERS FROM STACK

pointer can point to memory onlywithin the first page. TTYOUT is aroutine (not shown) which prints thecontents of the accumulator to theterminal. This routine varies fromone computer system to the next.

JOBS signifies the number of jobsthat we want to multitask; in thiscase, there are three (Huey, Duey,and Luey). STACKLEN signifies thelength of each program's stack.SPTABLE is a table of length JOBS,to be used exactly like a stack pointer.Each job has its own stack pointer,which is stored in the table when oneparticular job is asleep. CURJOB con-tains the number of the job currentlyrunning. In this example, CURJOBmay have only the values 0 (whichmeans Huey is running), 1 (Luey), or2 (Duey).

STACKAREA is JOBS X STACK-LEN bytes long (3 X 20 = 60 in this

182 October 1981 © BYTE Publications Inc

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Multi-user. Multi Tasking. Decision I™ memory man-agement hardware includes a memory map that issimilar to the IBM 360;" and IBM 37CT It supportsup to 16 tasks or 15 users and a supervisor withoutswapping. And, more with swapping. Each task oruser enjoys complete memory protection and dynamicmemory allocation. One task may be delegated as asupervisor to privileged system functions forbiddento ordinary tasks or users. Such functions (I/O calls,unauthorized memory access, etc.), will trap to thesupervisor. If supervisory functions are not requiredthe system can be configured for turnkey multi-useroperation.

Multi-purpose IEEE696/S-100. Decision I utilizes theMorrow Designs IEEE Standard S-100 Wunderbuss:"That means you can configure it to yourspecific applications. Add a floating pointprocessor, add memory (to a full mega-byte), add I/O, add controllers...addboards from dozens of manufacturers.And S-100 has a major advantageover single-board computers: If aboard goes down, you simply replaceit. And keep running. If you want toexpand your system. Add boardsand terminals.

An unmatched software base.

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example), and houses the actual stackfor each program. Since in the 6502the stack "grow" upward (toward

page zero), each program's stack hasa label pointing to the bottom of thestack. As a stack is used, the pointer

Figure 1: Saving a return address in thestack during execution of the SNOOZEprogram (shown in listing 2). Whenever amachine-level subroutine is called, themicroprocessor forces the return addressonto the stack. Later, when an RTS(return) instruction is executed, themicroprocessor retrieves the return ad-dress from the stack and puts it into theprogram counter. As a result, executingan RTS instruction causes the micro-processor to branch to the start of thesubroutine.

m-3m-2m-1m

m + 1m + 2m + 3

-SP

I BEFORE I

m-3m-2m-1m

m + 1m + 2m + 3

■SP

AFTER I

SP= STACK POINTER

RAH = RETURN ADDRESS, HIGHER ORDER

8 BITSRAL = RETURN ADDRESS, LOWER ORDER

8 BITS

steps along the stack.

Now that we have definedvariables and stacks in page zero, wemust fill those variables with mean-ingful values. PSECT tells theassembler that the following is pro-gram code, to be placed somewhereother than page zero. Label START-UP is the place we'll branch to inorder to begin the programs.

Before Huey, Duey, and Luey run,however, we must complete in-itialization. SEI disables the 6502 in-terrupts—just a precaution in case weforget to disable interrupts after thelast program. CLD clears the 6502decimal mode, and is another generalprecaution, rather than a unique re-quirement of multitasking.

The next twenty instructions leadto one goal: to fill the bottom twobytes of each stack with the startingaddress of the program so that we can

^w A1IZ' S

Picture the fastest, most accurate schoolteacher you ever had, point-ing out all your spelling errors so you can correct them instantly.This new spelling checker for Electric Pencil and Scripsit files ismodeled after her: it's virtually impossible to misspell with MIZ SPELL!Unlike other spelling checking programs:MIZ SPELL will operate on one or more disc drives. (Some othersrequire a minimum of two.)

MIZ SPELL will work with words of any length.(Others have limitson maximum word length.)

MIZ SPELL is interactive; you can correct mistakes as they arepointed out. (Some require multiple, time-consuming passes.)Check these features vs. other spelling checkers:MIZ SPELL maintains separate dictionaries for specialized vo-cabularies, each with a 27,000 word capacity. (18,000 included.)

MIZ SPELL learns new words from your text files as it checks for

spelling errors. (Words can also be deleted from the dictionary—

but not accidentally, as with some other programs.)

MIZ SPELL offers such options as: ignore word in text, delete word

in text, change word in text, add all remaining words, etc.

MIZ SPELL permits user configuration of system, including specifi

cation of default extensions for original and corrected text file.

TRS-80 Model I CCHOR CP/M 8" $"7Q95

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TRS-80 and TRSDOS are registered trademarks of Tandy Radio Shack Corp.CP/M is a registered trademark of Digital Research.

FOR TRSDOSOR CP/M

Meet author ARNOLD SCHAEFFER

Attends Georgia Tech starting Fall, 1981;

plans to major in computer science. First

exposed to computers in 6th grade; sold

first program at age 16. Characterizes

self as "not a good speller"; was

inspired to write MIZ SPELL when

he examined available

programming in store, decided

could have been done

much better"

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186 October 1981 © BYTE Publications Inc

Circle 411 on inquiry card.

DOS, DOS/VS, DOS/VSE, EDOS Systems Programmers

A good career fit is often hard tofind. . .and definitely worth lookingfor.

If you're an IBM DOS, DOS/VS,DOS/VSE, or EDOS operating systemsprofessional, your search is over.Nixdorf Computer Software Company,Richmond, VA, is the company tailor-made for your talents and ambitions.

NCSC: Small company infor-mality. Big company resources.

As a wholly-owned subsidiary ofNixdorf Computer Corporation,Waltham, MA, NCSC offers theperfect environment for your personaland professional growth. You'll workwith other talented professionals insmall project teams at the leadingedge of operating systems develop-ment technology. Our atmosphere en-courages and rewards creativity andinnovation. And it's all backed byNixdorf Computer's internationalreputation.

Our simple philosophy:Challenged and happy peopleproduce the best work.

At NCSC, we're firmly committed tostate-of-the-art technological ex-cellence—placing us on the Dataprosoftware honor roll for 3 consecutiveyears. So your talent will be chal-lenged and stimulated to grow andmature. Our creative environment,professional attitude, and friendly at-mosphere blend to provide a trulyenriching career experience.

What about the benefits?

They're outstanding. Health, majormedical, life, dental, prescriptiondrugs, short-term and long-termdisability, vacations and holidays, sav-

ings and investment plan, direct paydeposit, 100% tuition reimbursement,in-house training and education pro-grams, and more. Sounds great?You're right.

Nationwide Locations.

NCSC has regional offices in some ofthe most desirable cities in the U.S.Several opportunities are available inDallas and Chicago, with the majorityof positions open at NCSC head-quarters in Richmond, Virginia.

In Richmond, the emphasis isoutdoors.

Golf in January. Enjoy your favoriteoutdoor activities 9 to 10 months ayear. Sensibly-priced homes onfamily-sized building sites. You'll likeliving in Virginia's state capital, withits cosmopolitan, professional am-bience, 600,000 metro population,within 2 hours from Washington, D.C.,the Blue Ridge Mountains, or theseashore. And your very competitiveNCSC salary goes a lot farther withRichmond's low cost of living.

Our Current Opportunities:

For all these positions, you shouldhave at least 2 years IBM DOS,DOS/VS, DOS/VSE or EDOS operatingsystem experience and be proficientin Assembly language programming.Teleprocessing, networking, RJE,VSAM, BTAM, VTAM and CICS wouldbe valuable.

Operating SystemsProgrammer.

Design and develop from ground floora complete software system, in-cluding operating systems and com-munications software.

Software SupportRepresentative.

Provide customer support for Nixdorfoperating system software. Customercontact and troubleshooting ex-perience essential.

Systems Programmer.

Provide program fixes, implementenhancements, and assist customersupport efforts.

Support Systems Programmer.

Perform systems generation,maintenance, and other software sup-port functions for in-house develop-ment, support and production.

Technical Instructor.

Conduct in-house and customereducation for our operating systemproducts; travel involved. Instructionproficiency essential.

Technical Writer.

Provide internal documentationdevelopment programs. We seek aprofessional whose talents combinesystems programming experiencewith strong technical writing skills.

If you're interested and feel you'rethe right fit for one of our oppor-tunities, please forward your resume,stating your area of interest and in-cluding your salary history, toEmployment Manager, Dept. B,Nixdorf Computer Software Company,6517 Everglades Dr., Richmond, VA23225. Or call — outside of Virginia— TOLL FREE 800-446-9900. InVirginia, 804-276-9200. We are anequal opportunity employer m/f/h.

Committed to Success.

NIXDORF COMPUTER SOFTWARE COMPANY

NIXDORF

COMPUTER

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THE M

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The IBC ENSIGN business computer wasdesigned from the ground up to run MP/M, multi-user OASIS, MVT-FAMOS, and other multi-userZ-80 operating systems faster than any othercomputer in the world.Consider these features:

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fake a jump instruction with a returninstruction. When we call a machine-level subroutine, the microprocessorforces the return address onto thestack, and jumps to the subroutine(see figure 1). The opposite (poppingthe stack, and jumping to the returnaddress of the function whichoriginally called the subroutine)occurs when the microprocessor ex-ecutes a return from the subroutine(RTS in 6502 assembly language).

Thus, if we put the starting addressof the program on the stack, then ex-ecute an RTS, the microprocessorbranches to the start of the program.The entire operation is simple, butlets us perform several clever tricks.

Starting at STKINIT, we initializethe stack areas. #LSB is an assemblerfunction that extracts the LSB (least-significant byte) from the value inparentheses. TXS transfers the valuefrom the X register (which contains

STACKAREA:

4

H STACK:

4

DSTACK:

Luey's stack pointer) to the stack-pointer register. Similar to #LSB,#MSB is an assembler function thatextracts the MSB (most-significantbyte).

In the next several instructions, wewill place two bytes, which are thestarting address of program Luey, onthe stack. PHA pushes the value ofthe accumulator onto the stack. Wethen store the value of the stack-pointer register into the SPTABLE ar-ray offset by 1 (remember how CUR-JOB's value of 1 means Luey is run-ning?). Next, we initialize Duey'sstack exactly as we did Luey's, exceptat the end we store the stack pointerinto SPTABLE with an offset of 2 in-stead of 1. We now set the stack-pointer register to Huey's stack area,since Huey will run first (see figure 2).We must also set CURJOB to signifythat Huey will be running (CUR-JOB = 0). Finally, we jump to Huey,

4-

V HUEY'S/STACK

6502 STACK POINTERPOINTS HERE JUSTBEFORE THE JMP HUEYIN STKINIT

DUEY'S STARTING ADDRESS(HIGH 8BITS)

DUEY'S STARTING ADDRESS(LOW 8 BITS)

4>

v DUEY'St STACK

4

LUEY'S STARTING ADDRESS(HIGH 8 BITS)

LUEY'S STARTING ADDRESS(LOW 8 BITS )

LUEY'SSTACK

LSTACK:

Figure 2: The state of the stack area immediately before the JMP HUEY instruction inthe STKINIT subroutine of the SNOOZE program (see listing 2). STKINIT initializesthe stack areas. Since the stack-pointer register is now pointing to Huey's stack area,Huey will run before the subroutines Duey and Luey.

188 October 1981 © BYTE Publications Inc

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and whiz...everything is up and run-ning.

Each of the programs Huey, Duey,and Luey prints the first letter of itsname to the terminal. LDA is a loadaccumulator immediate, and loadsthe accumulator with the character"H," "L," or "D," depending onwhich program is running. JSR (jumpsubroutine) TTYOUT calls theroutine that prints the value of the ac-cumulator to the terminal. JSR SLEEPcalls the sleep routine. JMP HUEYcompletes the program by jumping tothe start of the program. Notice howeach program is a closed loop. Pro-grams Duey and Luey are exactly likeHuey, except for the characters theyprint.

The SLEEP routine is the mostmagical of all. SLEEP first uses theTSX instruction to save the value ofthe stack-pointer register in the Xregister. LDY loads the value of CUR-JOB into the Y register. INY in-crements the Y register. The CPY in-struction compares the incremented Yregister against JOBS (containing thenumber of total jobs, three in our ex-

ample) to see if we are at the end of acycle.

If not, BNE branches to NOZEROif the incremented Y register minusJOBS is not zero. However, if wehave reached the end of the cycle,then the LDY instruction loads zerointo the Y register. At labelNOZERO, the contents of the Yregister are stored into location CUR-JOB, reflecting the job to be run next.The LDX instruction loads a stack-pointer value from SPTABLE, offsetby the Y register (which equals CUR-JOB) into the X register. The TXS in-struction then transfers the value ofthe X register into the stack-pointerregister. Finally, an RTS effectivelyforces a branch to the program in-dicated by CURJOB. SLEEP, while alittle tricky, is short and sweet.

SLEEPR can be called instead ofSLEEP if we want to preserve the con-tents of our CPU registers before go-ing to sleep. SLEEPR simply pushesthe contents of all registers onto theprogram's stack, then calls SLEEP.After returning from SLEEP (andallowing the other programs to run),

SLEEPR restores the CPU registers bypopping them back off the stack.

The three programs won't actuallyrun simultaneously, but they will runin such rapid succession that, formost purposes, they will appear to berunning at once. When we executeSNOOZE, the terminal instantlydisplays:

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Other Applications

There are, of course, many uses formultitasking. Timeshared BASICSfor multiple users or for single userswith multiple programs are onepossibility. Real-time (ie: the pro-gram runs and interacts with externalevents), multiuser dungeon gameswould appeal to the fantasy-minded.For control applications, we couldassign a single microprocessor theduties of monitoring many in-struments, each instrument having itsown subprogram.

For complex operating systems, wecould assign printer spooling (variousprograms writing to the same

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190 October 1981 © BYTE Publications Inc

Circle 296 on inquiry card.

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printer), keyboard polling, andfloppy-disk management, to theirown multitasked programs. Musicsynthesizers could produce multipletones from software designed forsingle tones.

At Cornell University's low-temperature physics group, we havewritten multitasking software for the6502 that implements the HPIB func-tions (Hewlett-Packard InstrumentBus, also known as IEEE standard1978-488). This standardized bus isused not only in laboratory in-struments, but also in the Com-modore PET computer as a peripheralport. While it is possible to programall these routines using other softwaretechniques, the use of SLEEP maysimplify conception and implementa-tion.

Let's take a closer look at how wemight multiprogram a standardBASIC. First, we must have enoughfree memory in our system to hold atleast two different BASIC programs.The best method of multitaskingBASICs involves updating BASICspointers to the start of the program

memory, variable areas, etc.However, this method is complex andyou must know where these pointersreside in memory for your particularBASIC. Let's consider a simpler butless efficient method.

The general scheme is to swap outthe BASIC program, variables, andline counter (the value indicating thenext BASIC line to be executed), andthen swap in the next program's pro-gram, variables, and line counter.The addresses vary depending onwhich BASIC we use. Since mostcomputers have only one keyboardand display, we must have a way toindicate which program we wish tocommunicate with at any given time.To accomplish this, we must choose aspecific keyboard command. Finally,we must decide how often we wantthe computer to swap the programs inand out. We could do this in soft-ware, similar to SNOOZE, by callingSWAP occasionally. Or we couldforce swapping by pulling a hardwareinterrupt.

A hardware interrupt is, basically,a method of forcing the execution of

specific software when the propersignal is sent on the interrupt line. Wecould connect a timing device to theinterrupt line, forcing a SWAProutine to swap BASIC programs atevery clock period of our timer.SNOOZE could also be implementedusing this interrupt approach.However, the requirement of such in-terrupt hardware is a slight disadvan-tage.

Now that you have seen the struc-ture of the SLEEP method of multi-tasking, you may want to try writingyour own multitasking software. Forthe small-computer owner whothinks he is outgrowing his system,the convenience and added power ofresource sharing can be a strong in-centive to implement multitasking.All too often, our first reaction to astrain on resources is to buy a newsystem. But a better reaction might beto write such software. The SLEEPmethod may help your present com-puter system perform beyond yourexpectations. If your system seemsoverburdened and worn out, maybeit just needs a little SLEEP. ■

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192 October 1981 © BYTE Publications Inc

Circle 321 on inquiry card.

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Tree Searching

Part 2: Heuristic Techniques

Gregg Williams, Senior Editor

Exhaustive tree searches, forreasons that will be explained later,will eventually arrive at an optimalpath between the start node S and thegoal node closest to S. The exponen-tial expansion of many problems canoutgrow the memory and speed capa-bilities of even the largest computers;because of this, methods have beendeveloped that selectively limit thenumber of nodes expanded but stillinclude those nodes that lead to theclosest goal node. These heuristictechniques work by extracting infor-mation from the node and using it todetermine the likelihood of being onthe best path to a goal node.

In this article we will be concernedwith two types of heuristic tech-niques, admissible and nonadmissi-ble, and will experiment with them,using the BASIC program given in thefirst part of this article. (See "TreeSearching, Part 1: Basic Techniques,"September 1981 BYTE, page 72.)

Admissible-Algorithm Theory

One method of searching a prob-lem tree is to order the list of opennodes by giving each node a numericvalue and having the program choosethe node with the lowest value for im-mediate expansion (an approach usedin the SEARCH program in Part 1 ofthis article). Although this methodcan be used with any ordering thatproduces a successful search, a mild

restriction on the nature of the order-ing produces a search algorithm thatis guaranteed to find both a goal nodeand the optimal goal node—that is,the goal node that has the smallestcosf associated with it. This algo-rithm is called admissible.

Refer to the partial tree shown infigure 1. (Here we will assume thatthe paths from S to n and from n to Gare the shortest paths available.)Define g(n) as the shortest path fromthe start node S to node n; define h(n)as the shortest path from n to theclosest goal node G. Then

fln) = g(n) + h(n)

is the cost of the optimal path to agoal node, given that the solutionmust go through node n. (If no suchpath exists, the cost is said to be unde-fined; with a program, the appropri-ate cost variable would be assignedan arbitrarily large number.)

Now that we have the three func-tions /, g, and h, let us define threemore functions, f (pronounced"f-hat"), g, and n, that, for a givensituation, are estimates of the theoret-ical (and often unknown) minimalfunctions /, g, and h. In other words,/(n) is the estimated cost of theminimal path from S through n to G;g(n) is the estimated cost of the min-imal path from S to n (remember thatwhen we have a path from S to n, it

may not be the minimal path); andh(n) is the estimated cost of theminimal path from n to the closestgoal node (which, at the time, isunknown).

Simply stated without proof, thecondition necessary for an algorithmproducing h(n) to be admissible isthat the ordering algorithm must pro-duce a numeric value that is guaran-teed, for every node n, to be less thanor equal to the cost of the minimalpath from n to the closest G. In sym-bols, this condition is the following:

fM < /(n)

If this condition is always true, thenthe ordering algorithm is admissible.(Readers interested in the proof canconsult Problem Solving Methods inArtificial Intelligence, by Nils JNilsson, 1971, pages 59 to 65.)

Let us consider two cases of algo-rithms that are known to be admissi-ble. The first algorithm is that for abreadth-first search, which offers noinformation about the relative valueof any node—that is, /r(n) = 0. (Note:the computer program in Part 1 useda different value for the n(n) variableDl for demonstration purposes; how-ever, Dl = 0 will give the sameresult.) Since zero is a lower boundon the minimal cost of any node, goalor nongoal (ie: 0</z(n)), the breadth-first algorithm is confirmed to be ad-

Cirole 389 on inquiry card.

October 1981 © BYTE Publications Inc 195

Figure 1: A partially drawn tree. In this representation, each state (or node) of the prob-lem is represented by a point, and each line represents a legal change from one state tothe next. Node S is the original problem, with node n and other nodes representing in-termediate steps on the way to solution (node G, the goal node).

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missible by the above inequality. But,as we know from experience, thebreadth-first algorithm is nonselec-tive; that is, it expands all nodes inorder of increasing depth until itreaches its first (and therefore mini-mal) goal node. So we can see that itstotal absence of heuristic informationgoes hand in hand with, and is ameasure of, its extreme inefficiency.

On the other hand, let us assumean ordering algorithm fi that returnsthe exact cost of the shortest pathfrom n to G; in other words, /z(n) =h(n) for all n, which still satisfies theabove inequality. What does thismean? A moment's reflection willconfirm that, first, since this algo-rithm represents perfect informationabout the state of the system, it isguaranteed to reach the nearest goalnode G; and, second, that it will doso without expanding one unneces-sary node. What could be simpler7Since the search algorithm always ex-pands the node with the smallest nvalue, and since in this case the nvalue is the exact cost from that nodeto the goal node, the search algorithmwill inexorably come, with each ex-pansion, one node closer to the goalnode. So in this case, the presence oftotal heuristic information is equiva-lent to maximum efficiency.

From viewing the above two ex-tremes representing

and

/i(n) = 0fi(n) =-Mn)

we would expect to find an /t(n) satis-fying

0 < /i(n) < fe(n)

to be between these two extremes ofefficiency, with efficiency increasingas /i(n), for all nodes n, approachesh(n). This is actually the case: giventwo admissible ordering algorithms A(generating /i(n)) and A* (generatingA*(n)), A* is said to be more informedif n* is always greater than or equalto «, or:

£(n) < /.*(n) < Mn)It has also been shown that A* is then

196 October 1981 © BYTE Publications Ire

Circle 192 on inquiry card.

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Listing 1: The "out-of-place" algorithm. Listing la gives the algorithm as implementedin BASIC, to be inserted in the SEARCH program in Part 1; listing lb shows the struc-tured pseudocode for the algorithm. In this and subsequent listings, the string value ofeach piece is replaced by its corresponding numeric value (ie: piece "1" has value 1),with 'A" through "F" being replaced by the values 10 through 15, respectively.

(la)

988198849885

9887989599009910991599209925993099359940

994599609965

(lb)

99009910

99159920

99359945

9960

9965

REM LISTING 1

REM

REM "OUT-OF-PLACE" ALGORITHM,

-ADMISSIBLE

REM

REM

R1=0

FOR 1 = 1 TO R9; FOR J= 1 TO R9

Q = ASC (E$(IJ))

IF Q = 46 THEN 9960

IFQ>64THENN = Q-55: GOTO9935

IFQ< =57THENN = Q-48

P1=R9*(I-1) + J

REM —PI IS VALUE OF CORRECT

TILE IN POSITION 1,1

IFN <> PI THENR1=R1 + 1

NEXT J: NEXT I

RETURN

value of puzzle (R1) = 0for each row I

for each column J

Q = ASCII value of row I, column J of puzzle E$if piece not "." (Q=*46)

convert piece Q to "true" value NPI = value of piece in row I, column J in goal nodeli current piece ^ value of same position in goal node: new value of puzzle = old value of puzzle + 1

endliendiiend of for-loop Iend of for-loop Ireturn

guaranteed to expand an equal orsmaller number of nodes than A(again, see Nilsson, mentionedabove).

One more point has to do with adifference between tree and graphsearches. The cost of a node about tobe expanded, g(n), is equal to its theo-retical minimal cost g(n) in a treebecause, by definition, there is onlyone path from the root node S to anyother node. Since a graph may con-tain more than one path from S to n,the cost of a path found may not bethe minimal one and so must be la-beled g(n). However, an admissible

198 October 1981 © BYTE Publications Inc

algorithm that does not change itsnature during the graph search willproduce only optimal paths to ex-panded nodes, so that g(n) = g(n);the formal name for the conditionthat guarantees this result is the con-sistency assumption. All admissiblealgorithms used in this article satisfythis assumption.

Some Examples

The exhaustive searches examinedin Part 1 of this article (breadth-first,depth-first, and limited depth-firstalgorithms) are all admissible and ex-hibit one extreme in the information

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spectrum: they contribute no heur-istic information to the solution of theproblem, so h\(n) = 0. The other ex-treme, that of perfect information (orn(n) = h(n)), is certainly interesting intheory, but impossible to implementin most cases. We will examine twoadmissible algorithms that fall be-tween these two extremes.

Remember that we are seeking todefine a function /(n) that is a lowerbound on the minimal number ofmoves from node n to a goal node G.One plausible algorithm (see listing 1)is the following: f(n) equals the num-ber of squares that are not in the same

position they are in the goal node G.(In the 8- and 15-puzzles used for illu-stration, there is only one goal nodeG.) The informed reasoning used toprove that this is a lower bound onthe actual cost to the goal node is thefollowing: if a square (not includingthe "space" square) is out of place, itwill take at least one move, if notmore, to put it in place; thus, the ft(n)generated by this "out-of-place" algo-rithm will always be less than orequal to the cost of a solution h(n).

Table la shows the puzzles used inthis article; table lb shows the resultsof applying both the breadth-first and

the "out-of-place" algorithms to thesepuzzles. A comparison of the firstseven lines of table lb prompts sev-eral useful observations. First, thebreadth-first search is considerablymore inefficient than the "out-of-place" algorithm; the computer Iused, which has 20 K bytes of work-space and will hold 52 nodes beforerunning out of memory, can completeonly a four-move puzzle with the firstmethod, but can complete sometwelve-move puzzles with the secondmethod before running out of mem-ory. Second, both algorithms show aroughly linear increase in the number

(la)

Row

Column 1

Column 3

1

2

3

1

47

5

68

1

2

3

1

2 3

2

4

6

4

5 6

7

5

8

7 8

1

2

3

1

2 3

3

4

6

5 6

7

5

8

4

7 8

1

2

3

1

2 3

4

7

4

6

5

. 6

5

8

4

7 8

1

2

3

1

2 3

5

7

4

6

5

7 6

5

8

4

. 8

1

2

3

1

2 3

6

7

4

6

5

7 6

5

8

4

8 .

1

2

3

1

2 3

7

7

4

5

7 .

5

8

6

4

8 6

1

2

3

1

2 3

8

7

4

5

. 7

5

8

6

4

8 6

1

3

1

3 .

10

7

2

4

5

2 7

5

8

6

4

8 6

7

1

3

1

3 7

12

2

4

5

. 2

5

8

6

4

8 6

7

1

3

1

3 7

14

2

8

4

5

8 2

5

6

4 6

7

1

3 7

16

2

8

3

1

8 2

5

6

4

5

4 6

7

8

1

3

8 7

18

2

3

1

. 2

5

6

4

5

4 6

(lb)

Puzzle

(1,1)

(2,1)(2,3)

(3,1)(3,3)

(4,1)(4,3)

(5,1)(5,3)

(6,1)(6,3)

(7,1)(7,3)

(8,1)(8,3)

(10,1)(10,3)

(12,1)(12,3)

Table 1: Comparison of breadth-first and "out-of-place" algorithms on selectedproblems. The puzzles in table la can be identified by a pair of numbers giving therow and column in which the puzzle is found. The row number gives the number ofmoves to solution; puzzles in the same column are subsets of the same problem.(These match puzzles listed in Part 1 of this article.) Table lb gives a comparison ofbreadth-first versus "out-of-place" algorithms for selected problems. The relation-ship between nodes open and nodes closed is: total = nodes open + nodes closed.COM* indicates that the computer's limit of about 50 nodes was exceeded. Theparentheses around the 29 in line (5,1) denote that the breadth-first search ran out ofroom after expanding 29 nodes.) The "out-of-place" algorithm's ability to solve morecomplex problems using the same amount of memory indicates greater power whencompared to the breadth-first search.

NodesOpen

Breadth-FirstNodesClosed Total

NodesOpen

"Out-of-Place"

Nodes

Closed Total

3

1

4

3

1

4

74

43

11

7

53

22

75

910

89

1719

64

33

97

12

16

1121

2337

66

4

4

1010

*OM*

(29)

*OM**OM*

97

76

1613

*OM**OM*

1213

9

13

2126

*OM**OM*

1317

1017

2334

*OM**OM*

1425

1126

25

51

*OM**OM*

14

13

27*OM*

*OM**OM*

20

20

40*OM*

200 October 1981 © BYTE Publications Inc

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of nodes expanded within a certainrange (levels 1-3 and 1-4, respective-ly), with the ratio of nodes expandedto the theoretically minimum num-ber of nodes to be expanded beingroughly 3:1 and 1:1, respectively.Third, this ratio progressively in-creases outside each algorithm's rangeof linearity; this implies that the max-imum efficiency available from eachalgorithm decreases with the com-plexity of the puzzle—in other words,as the puzzle becomes more involved,the fi that is calculated drifts moreand more from the theoretical h to-ward zero (ie: no information), andthe algorithm breaks down (ie: ap-proaches an exhaustive search).

A final observation is that the (n,l)puzzles seem easier to solve than the(n,3) puzzles. (Puzzles with the samelast subscript are extensions of eachother.) This trend is more obvious oncomparison of the numbers in the"nodes closed" column in table lb(which is a measure of the difficultyof the problem in that it is related tothe number of nodes expanded in theattempt to find a solution). Note alsothat the nonlinear rise of the "nodesclosed" column is greater for the (n,3)puzzles than for the («,1) puzzles.This suggests that the behavior of analgorithm outside the range of linear-ity described above cannot be ex-pressed by a simple nonlinear func-

Listing 2: The minimum-distance algorithm. Listing2a gives the algorithm in BASIC, tobe inserted in the SEARCH program of Part 1; listing 2b is the structured pseudocode.(2a)

9885 REM —LISTING 2

9887 REM

9890 REM MINIMUM-DISTANCEALGORITHM; ADMISSIBLE9893 REM

9910 REM

9900 R1=0

9910 FOR I = 1 TO R9: FOR J = 1 TO R9

9915 Q = ASC (E$(I,J))

9920 IF Q = 46 THEN 9960

9925 IF Q>64 THEN N = Q-55: GOTO 9935

9930 IFQ<=57THENN = Q-48

9935 I1=INT((N-1)/R9) + 1

9940 REM —GIVEN SQUARE N,1<=N<=15, FIND

9941 REM (11,11) = POSITION OF N INSOLVED PUZZLE

9945 I1=N-R9*(I1-1)

9950 REM —H-HAT IS SUM OF DISTANCESEACH SQUARE

9951 REM IS FROM GOAL POSITION; "."SQUARE NOT COUNTED

9955 R1=R1+ABS(I-I1) + ABS(J-J1)9960 NEXT J: NEXT I9965 RETURN

(2b)

99009910

99159922

993599459955

9960

9965

value of puzzle (R1) = 0for each row I

for each column J

Q = ASCII value of row I, column I of puzzle E$if piece not "." (Q^46)

convert piece Q to "true" value NII =row § of piece in goal nodeJl = column # of piece in goal nodenew value of puzzle = old value of puzzle +(difference of row values) + (differenceof column values)endlfand of for-loop Iend of for-loop Ireturn

tion, but only through a range ofvalues that is highly sensitive to theindividual puzzle under considera-tion.

Minimum-Distance Algorithm

The minimum-distance algorithmdescribed here is the most efficient Ihave worked with—one that I havenot been able to improve even whendropping the admissibility constraint.The algorithm (see listing 2) may bedescribed as follows: for each piece inthe puzzle (not including the "."piece), the value of the algorithm isincreased by the number of rows plusthe number of columns the piece isaway from its final position in thegoal state (ignoring any pieces in theway). For example, if the "1" piece isin row 2, column 3, then that piece is(2 — 1) + (3 — 1) = 3 squares away fromits final goal position (row 1, column1) and so adds 3 to the /value of thatpuzzle. Table 2 shows the value ofpuzzle (6,1) using this algorithm.

Because the figure given to eachpiece is a conservative estimate ofhow many moves it will take to getthat piece into place (it will be more ifthe other pieces get in the way), the fcalculated as the sum of these valuesmust be a lower bound on the truecost / associated with a given puzzle;therefore, this minimum-distance al-gorithm is admissible.

Table 3 shows the result of usingthis algorithm on the puzzles in Tablela, with comparison values given forthe "out-of-place" algorithm. Theresults are far more pleasing thanthose of any algorithm that we havelooked at—in fact, you might say thisis the first algorithm of any practicaluse. The algorithm, like the "out-of-place" algorithm, is "perfect" throughorder 4 (although a counterexamplemay exist), but notice that the non-linear increase in the "nodes closed"column is more gradual and morenearly straight-lined for the mini-mum-distance algorithm than it is forthe "out-of-place" algorithm. Al-though the minimum-distance algo-rithm does drift from the theoretical hvalue toward zero as the problemcomplexity increases, it does so lessseverely than the "out-of-place" algo-

202 October 1981 © BYTE Publications Inc

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rithm; this is because the minimum-distance algorithm is more informedthan the other algorithm. Its better in-formation is expressed in the gener-ation of fewer erroneous nodes dur-ing the solution of a puzzle.

One aspect of table 3 is, however,misleading: the order-12, -14, and -16puzzles show identical "nodes closed"values for two sets of puzzles thatwere earlier said to be unequal incomplexity, which might suggest thatthe algorithm somehow minimizesthe scatter effect caused by the dif-ferent complexities of puzzles of thesame order postulated earlier. This,however, is not the case: solution bythe minimum-distance algorithm of anumber of randomly selected order-12puzzles reassured me that no suchminimizing effect was taking place;the values in "nodes closed" for thesepuzzles were 12, 13, 14, 14, 18, 20,and >20 (this last value was theresult of the computer running out ofmemory).

Although the minimum-distancealgorithm is usually reliable, there isat least one type of problem thatrenders it virtually useless. An exam-ple of one such puzzle is given infigure 2, and an analysis of the algo-rithm's inability to solve it gives us aclue toward the construction of amore powerful admissible algorithm.Although the algorithm gives thispuzzle a value of four, I have notbeen able to find a solution (by hand)of under sixteen moves, and the firstfifty nodes of the tree, generated bythis algorithm before my computerran out of memory, show no ap-preciable gain toward the goal node.In fact, after generating nodes 37through 40, at level 10 (see figure 2),the algorithm abandons them to ex-pand nodes of levels 2 through 4,clearly indicating that the algorithmhas found the nodes on levels 6through 10 to be unpromising. Al-though I have failed to find an admis-sible algorithm that performs betterwith this puzzle, I am sure that suchan algorithm will have to take intoaccount the extra number of movesthat pairs of pieces in each other's"home" positions (here, the "5" and"6" and the "7" and "8") generate.

Nonadmissible Algorithms:Theory

Comparatively little is knownabout the performance of nonadmis-sible algorithms—that is, algorithms

whose returned value r\ is not neces-sarily a lower bound on the true costof a solution h. This is because nocommon feature (in terms of the algo-rithm's goal-finding performance)

(a)Puzzle

1 2 37 4 65 8 .

(b) ' (C)

Goal Node Breakdown of Moves

1 2 3 pieces 1,2,3,6,8 in place =0

4 5 6 piece 4 is 0 rows, 1 column off = 1

7 8 piece 5 is 1 row, 1 column off = 2

piece 7 is 1 row, 0 columns off =J_

f value of puzzle = 4

Table 2: Evaluation of puzzle (6,1) by the minimum-distance algorithm. Thisalgorithm sums the distance each piece is from its final position (the goal node) to ar-rive at an estimate of the number of moves to solution. Column (a) is the problemposed in puzzle (6,1); column (b) is the goal node; column (c) gives each piece's con-tribution to the total number of moves to solve the puzzle (the "." piece, whichrepresents the blank, is not included in the evaluation).

Puzzle

"Out-of-Place"Nodes Closed Total

MinimumNodes Closed

DistanceTotal

(1,1)

1

4

1

4

(2,1)(2,3)

22

75

22

75

(3,1)(3,3)

33

97

33

9

7

(4,1)(4,3)

44

1010

44

1010

(5,1)(5,3)

76

1613

65

1312

(6,1)(6,3)

913

2126

7

7

1515

(7,1)(7,3)

1017

2334

77

1515

(8,1)(8,3)

1126

2551

810

1821

(10,1)(10,3)

13

27*OM*

1012

2124

(12,1)(12,3)

20

40*OM*

14

14

2929

(14,1)(14,3)

*OM**OM*

1616

3232

(16,1)(16,3)

*OM**OM*

1818

3535

(18,1)(18,3)

*OM**OM*

20

40*OM*

Table 3: Comparisonalgorithm for selected

of the "out-problems.

of-place"

algorithm with the

minimum-distance

204 October 1981 © BYTE Publications Inc

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that applies to nonadmissible algo-rithms as a class has been found: agiven nonadmissible algorithm, com-pared to a good admissible one, mayperform anywhere in the range ofconsistently better to consistentlyworse. In fact, it is possible to devisea nonadmissible algorithm that isworse than a "no-information"breadth-first search.

In any case, two characteristics of anonadmissible algorithm follow fromits failure to meet the conditions ofadmissibility. One is that it is notguaranteed to find a goal node; theother is that a goal node found by a

Listing 3: Modification needed to derivethe algorithm NA-I (nonadmissiblealgorithm 1). This modification to theBASIC code in listing 2 delivers misinfor-mation to the SEARCH program, render-ing it incapable of solving even thesimplest puzzles.

9890 REM — LISTING 3—

9891 REM

9894 REM ALGORITHM NA-I;NONADMISSIBLE

9896 REM INSTRUCTIONS: ADD THISCODE TO LISTING 2

9897 REM (THE MINIMUM-DISTANCEALGORITHM)

9898 REM

9899 REM

9961 REM

9962 L1 = 100-R11

]

nonadmissible algorithm may not bean optimal goal node (ie: there mayexist another, shorter, path to thesame node). These are serious but notinsurmountable defects when consid-ered in conjunction with a real-workproblem because, in the first place, agiven algorithm will not be usedunless it has a history of solvingsimilar problems. (Nonadmissible al-gorithms are devised by a process oftrial and error, and the only measureof a given algorithm's effectiveness isits ability to produce solutions toproblems of a similar complexitywhose solutions are already known.)In the second place, the production ofan optimal node may not be as im-portant as the production of somegoal node, optimal or otherwise.

(Other methods may be used inconjunction with or in place of non-admissible algorithms to produce agoal node. All these methods sacrificethe guarantee of finding a goal nodeby economizing on the number of in-termediate nodes saved. Successorscan be pruned from memory eitherwhen they are generated or whenmemory is filled; or, in a completelydifferent approach, a depth-firstsearch of a given maximum depthsweeps across the tree, storing onlythe best node encountered thus far.)

LEVEL 0

Listing 4: Modification needed to derivethe algorithm NA-II (nonadmissiblealgorithm 2). This modification to theBASIC code in listing 2 consistently per-forms as well as, or better than, theminimum-distance algorithm. Since thealgorithm is nonadmissible, the perfor-mance is not guaranteed.

9890 REM LISTING 4

9891 REM

9892 REM ALGORITHM NA - II;NONADMISSIBLE

9895 REM

9896 REM INSTRUCTIONS: ADD THISCODE TO LISTING 2

9898 REM

9899 REM

9954 REM

9955 I9 = ABS(I-I1):J9 = ABS(I-J1):R1=R1 + I9 + J9

9957 IFI9>0 AND I9>0 THEN R1=R1 + 1

Some Examples

An example of a bad nonadmissiblealgorithm is easy to generate: simplysubtract the value calculated by theminimum-distance algorithm (whichis a good algorithm) from an ar-bitrarily large number. This results inan algorithm that assigns a high num-ber to a node close to a goal node(making it one of the last to be ex-panded) and a lower number to anode that is further away from a goalnode; see algorithm NA-I, given inlisting 3. The algorithm, when runwith a problem of order 2 or greater,will fill up almost any computer'smemory without producing a solu-tion because this algorithm will ex-pand a "good" node only after it hasexpanded every worse node in theproblem tree. At fifty nodes (mycomputer's limit) on problem (2,1),the algorithm was much further awayfrom a solution than when it started.

On the other hand, an example of agood nonadmissible algorithm—inthis case, one that performs betterthan the minimum-distance algo-rithm—is much harder to find. Infact, a considerable amount of workin several directions yielded only onepositive result. The algorithm, la-beled NA-II (see listing 4), is an at-tempt to correct the minimum-dis-

123©4 6 58 7.4

LEVEL 1

LEVEL 2

1 2 3 (?)46.8 7 5 5

123©4 6 58.75

12 .©4 6 38 7 5 6

12 30

4 . 68 7 5

/ I \

O

THROUGH

36

LEVEL 10

1 2 37 . 54 6 8

(37)

6

12 3 12.7 6 5 7 8 3.48 456

(38)6

(39)6

1 2 37 . 84 5 6

©

6

Figure 2: A sample problem that is poorly handled by the minimum-distance algorithm.Although the algorithm predicted four moves to solve the puzzle, the computer ran outof memory before solving it. The circled number by each node indicates the order inwhich the nodes were generated; the numbers not circled are the f values predicted bythe algorithm.

206 October 1981 © BYTE Publications Inc

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Figure 3: Expansion of puzzle (5,1) by the minimum-distance algorithm (figure 3a) andNA-I1 (figure 3b). The numbers inside each node denote the order in which they weregenerated; the numbers not circled are the estimated f values generated by eachalgorithm. In this case, the nonadmissible algorithm performs slightly better.

GlossaryClosed node: a node whose successors have already been calculated.Cost (or value): a numeric value associated with the shortest path from the startnode S to the current node n; the cost of the first goal node found will have somemeaning within the problem being solved.

Depth: the number of nodes a given node is away from the start node S.Expand: to calculate all legal successors of the current node.

Goal node: any node satisfying the set of conditions defined as the desired final stateof the problem.

Node: an element of a tree used to represent a given state of the problem.Open node: a node that has not yet been chosen for expansion.Ordering algorithm: a formula or procedure generating an ordering value thatrepresents the node's relative likelihood of being chosen for expansion; the node withthe lowest ordering value will be expanded next.

Problem tree (or tree,): a graphic representation of the problem space (or state space)using dots to represent states, and lines connecting dots to represent the transitionfrom one state to the next; all nodes must be generated from one start node S thatrepresents the beginning state of the problem.

State: a specific set of values for the variables that define the problem.State-space representation: a breakdown of the problem into the following com-ponents: the state variables that can describe the problem in any of its possible con-figurations; the operators that generate the next set of values (or states) for the prob-lem given the current set (or state); a beginning state S; and a description (notnecessarily exact) of the goal node to be found.

Successors: those nodes representing all valid "next states" for a given node (or state)as defined by the operators of the state-space representation; the node generating thesuccessor nodes is called the parent node.

tance algorithm for harder problemsby adding 1 to the original value foreach node that is at least one row andone column away from its position inthe goal node. Only two puzzles outof the entire set did better than theminimum-distance algorithm (seetable 2), but the rest matched it, mak-ing NA-II a slightly better algorithm.Figures 3a and 3b show the expan-sion of problem (5,1) by the mini-mum-distance and NA-II algorithms,respectively, as well as the order inwhich they were expanded and thecalculated r\ estimate by each algo-rithm. Note that NA-II made the rightdecision in not expanding node 3,whereas the minimum distance algo-rithm underestimated the cost of node3 (whose true cost is 5) and unneces-sarily evaluated it. So we see thatNA-II, at least in this case, is betterthan the minimum-distance algorithmbecause it is less likely to under-estimate the value of a node (some-thing that an admissible algorithmtends to do). As an extension of that,however, we confirm that this algo-rithm is nonadmissible because itsometimes overestimates the value ofa node (something that an admissiblealgorithm cannot do). An example ofan overestimated node is node 2 infigure 3b; its true value is 6, but it wasestimated at 8 by algorithm NA-II.

Observations and Questions

• The word "cost," up to this point,has only been used to refer to thenumeric value associated with theshortest path from the node to theclosest goal node. But it has two newand significant meanings when refer-ring to the cost of a solution. Oneindex of the cost of a solution is thenumber of nodes closed (ie: ex-panded) by the algorithm—this is themeasure we have looked at whencomparing the efficiency of two algo-rithms. But another factor must beconsidered when either speed ormoney (as expressed in computertime) is a factor. That factor is thecomplexity of the evaluating algo-rithm giving r\. A more-informed al-gorithm may generate fewer nodesbut may take considerably more com-puter time to do it. If speed or money

208 October 1981 © BYTE Publications Inc

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becomes a critical factor before theamount of available memory does, itis possible that the user will decide touse the less-informed algorithm.

• (Question 1) How does a heuristicalgorithm assist the tree-searchingprocess? (See the textbox "Answers,"which appears on page 212.)

• (Question 2) In the description ofthe minimum-distance algorithm, the"space" square was not included inthe summing of "distances from homeplace." If this were done, would thealgorithm be more powerful? Less?Would it still be admissible?

• Is the tree in figure 4 possible if thealgorithm is admissible? Yes, but onlyif the algorithm is mistaken about theestimated value of one of the open

Figure 4: A hypothetical partially ex-panded tree, used for visualizing ques-tions posed in the text.

nodes (4, 5, 7, and 8). For example, ifthe optimal goal node is three nodesaway from node 4, then the suc-cessors of node 8 (or, at the latest,their successors) must all come upwith fi values greater than three sothat node 4 will be expanded next. Anadmissible algorithm will alwaysreach the closest goal node first.

• Is this tree possible if the algorithmis nonadmissible? Yes, a nonadmissi-ble algorithm puts no restrictions onthe validity of this tree.

• (Question 3) Remember the mean-ing of /, g, and /z:f(n) is the estimateddistance from start node S throughnode n to the closest goal node; g(n)and /i(n) are the estimated distancesfrom S to n and from n to the samegoal node, respectively. Isn't the treein figure 4 a good argument for using/instead of h~ to order the expansionof nodes7

• (Question 4) The minimum-distance algorithm has been the bestalgorithm we have seen for the 8- and15-puzzle. Try adding the line

9963 R1 = R1 * F9

to the /i-calculating subroutine at9900. This will increase the fi value tonodes that were formerly underesti-mated by the admissible algorithm.The algorithm will now be nonadmis-sible, but will it also be more "pierc-ing"? Try F9 = 1.01, 1.1, 1.5 (andother values), and test the new algo-

rithm on puzzles of eight moves ormore.

• (Question 5) Why is the nonadmis-sible algorithm NA-I a worse algo-rithm than the breadth-first search7Isn't an exhaustive search, which usesno heuristic information, the most in-efficient search possible?

• As mentioned before, certain modi-fications to the method of searchingmay be desirable over the use of anonadmissible algorithm. In certainsituations, the judicious applicationof one of these methods may be moreproductive in finding a goal nodethan the "pure" methods described inthis article.

Conclusions

This article has dealt with thesearching of state-space trees andgraphs. Other kinds of trees (AND/OR trees and game trees, to nametwo) are used in theorem proving andgame playing, and a number of otherquestions can be raised.

For example, how can we evaluatenonadmissible algorithms? Whatmodifications should we make whenwe have a limited amount of mem-ory? While I have discovered that xamount of artificial intelligence in aprogram requires at least "x cubed"amount of work, if not more, I hopethat this article will prompt morepeople to look into (and write about)this interesting branch of artificialintelligence.!

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211

Answers

1. A heuristic algorithm assists thetree-searching process using informa-tion in the current state (that is, in thecurrent node, without looking at itsrelationship to any other node but thegoal node) to assess the relativelikelihood of that node leading to asolution. More likely nodes receive alower value than less likely nodes, sothe controlling program, in choosingto expand next the node with thelowest ordering value, is choosing thenode most likely to lead to the shortestsolution.

2. This variation of the minimum-distance algorithm is slightly lesspowerful, primarily because it is nolonger admissible. The puzzle

12 34 5 6

7 . 8

is a simple counterexample. Since boththe "." piece and the "8" piece are onesquare away from their positions in the

goal state, this algorithm would returnthe value 2. However, since the truesolution value is 1, this one counterex-ample is enough to show that the algo-rithm is nonadmissible.

3. If the algorithm used is admissible,the use of fi guarantees finding theclosest goal node—this is mathemati-cally unarguable. But if the algorithmis nonadmissible and, at the same time,relatively accurate, the use of

f(n) = g(n) + (i(n)

may be a good idea indeed. If the esti-mate fi costs in figure 4 are accuraterelative to each other, then

f(node 4) = 1 + ft(node 4)

=1+3=4f(node 8) = 3 + h~(node 8)

=3+2=5

may rightly cause node 4 to be ex-panded first.

4. The results for this new algorithm

will be identical to those of the mini-mum-distance algorithm, even thoughthe new algorithm may be nonadmissi-ble. Multiplying the results by a con-stant will change the values of thenodes but not the ordering of the nodesto each other. On the other hand, add-ing

9963 if Rl > F8 THEN R1=R1+F9

9963 IF RKF8 THEN Rl=Rl +F9

will change the relationship of thenodes to each other. Experiment withthese for various values of F8 and F9; asuggested starting value for F8 is 4.5. No. Misinformation is worse thanno information at all, and that is whatNA-I is giving. In assigning high valuesto nodes that should be low, and viceversa, this algorithm is forcing thedriving program to always expand theleast promising node first.

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212 October 1981 © BYTE Publications Inc

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T/Maker II calculated and reported all the other values.

— Actual —

Growth

Total

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1978

1979

1980

Rate

Average

(000's)

1981

1982 * 1985

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42,323

51,891

65,123

24.04

53,112

159.34

80,782

100,206 191,262

ItemB

45,671

46,128

49.088

3.67

46,962

140.89

50,891

52,761 58,791

Total

87,994

98,019

114,211

13.93

100,075

300.22

131,673

152,966 250,053

% Item

48.10

52.94

57.02

8.88

52.69

158.1

61.35

65.51 76.49

% Item

51.90

47.06

42.98

-9.00

47.31

141.9

38.65

34.49 23.51

Total

100.00

100.00

100.00

—

100.00

300.0

100.00

100.00 100.00

*Two intervening years not shown.

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BYTE October 1981

213

Drawing with UCSDPascal and the Hiplot Plotter

Dr James Stork

Humbolt State University

Humbolt Bay Project

Areata CA 95521

In the course of my work for theUniversity of California Sea Grantprogram, I have needed to plotoceanographic data on a Houston In-strument Hiplot plotter. Because myoperating system is exclusively UCSDPascal, I have developed routinesusing that system. I have been com-pletely satisfied with this system andwould recommend it to anyone whointends to develop serious microcom-puter software beyond the level ofsimple computer games.

The plotter software shown in thelistings demonstrates at least twofacilities of the UCSD Pascal systemthat I have found very useful. Theseare the ability to easily link an exter-nal machine-language subroutine toany Pascal program, and to store alibrary of often-used units and pro-cedures in the system's library.

The "plotter" Unit

The main unit, called "plotter", is

About the Author

Jim Stork, a research oceanographer, hasbeen "a confirmed computer freak" since thebeginning of the microprocessor industry.Recently he has been using a Z80-basedmicrocomputer to do data acquisition andanalysis for a computer modeling study ofHumbolt Bay.

given in listing 1. Those of you whoare familiar with the Pascal languagewill notice that the normal programheading is absent, and in its place isthe declaration "unit plotter;" rather

Once a unit is written,

compiled, and stored in

the system library, it

can be used by any

Pascal program

through the "uses"

statement.

than "program plotter;". This is to in-form the compiler that the procedurescontained in this unit are meant to belinked to another "using" programand are not run alone.

The interface section in listing 1tells the linker that the followingdeclarations (one type and six pro-cedures) may be used by the programthat is linked to the unit. The im-plementation section variables andprocedures are to be used solely in theimplementation of the unit and arenot to be available to the programusing the unit. For example, the pro-cedure "plotstep" cannot be used bythe program using the unit (since it isnot named in the interface section of

the unit), while the procedure "plot-line" can be used.

Once a unit is written, compiled,and stored in the system library, itcan be used by any Pascal programby including the statement "usesxxxxx;" after the program heading ofthe using program (assuming the unitis named "xxxxx" in the library; seethe example in listing 2). When themain program is compiled and run,the linker will link the unit into theusing program and will link the pro-cedure "plotstep" (which is externalto "plotter") into the "plotter" unit.

It is important to note here that"plotstep" is not linked to the "plot-ter" unit before it is stored in thesystem library. Both the unit and theexternal procedure "plotstep" arestored in the system library in theircompiled and assembled versions,respectively. The linking of one to theother is done when the linker linksthem into the using program. (Thislittle piece of knowledge is not men-tioned anywhere in the UCSD Pascalmanual, and it caused me a con-siderable amount of grief until I calledSoftech to get myself back on theright path. The people at Softechhave given me a great amount of helpabove and beyond the call of duty;although their documentation mightbe less than complete, their helpful at-titude with problem calls leavesnothing to be desired.)

214 October 1981 © BYTE Publications Inc

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PLOTLINE (penpos:integer;xplot,yplot:real);

This procedure draws a line. Its parameters are:penpos: Position of the pen during the plot.Initialize the plotter.

This must be done before any plotting can be done. When penpos is 0 thecomputer assumes that the current pen location is location (0,0)—namely,the lower left corner of the plotting bed. The subroutine will remind you tomove the pen to that position before if actually sets these coordinates.When penpos = 0, xplot and yplot can be any values since they will be ig-nored.

Pen up (ie: no line will be drawn).Pen down (ie: line will be drawn).

x position (ie: left and right) in inches to which the pen will be moved. Thismay be any value from 0 to 10 inches.

y position (ie: forward and backward) in inches to which the pen will bemoved. This may be any value from 0 to 7 inches.

penpos = 0:

penpos = 1

penpos = 2

xplot

yplot:

PLOTSYMBOL (sym:integer;height:real);

This procedure is used by procedure plotarray to draw one of five symbols to represent adata point. The symbol is drawn at the current pen position. Its parameters are:sym: Symbol definition.height: Height of symbol to be drawn.

PLOTWHERE (var px,py:real);

This procedure will place thevariables px and py.

current pen position coordinates in inches into the

PLOTSTRING(px,py,height,theta:real; linerstring);This procedure plots a string of characters anywhere on the plot. Its parameters are:px,py: coordinates in inches of lower left corner of first character to be plotted,height: height of characters in inches.

theta: angle with respect to the x axis at which the characters will be drawn (indegrees),line: a string variable containing the characters to be drawn (maximum of 80characters)Subscripts and superscripts are supported by the software. In order to accomplishsuperscripting, enclose the letters to be superscripted in brackets (eg: this is a[superscript]). To create subscripts, use the brackets in reverse order (eg: this is a]subscript[). If an up-arrow is specified, it will be drawn with a length as specified in theheight parameter and pointing in the direction given in the theta parameter.in the direction given in the theta parameter.

PLOTAXIS(px,py,leng,theta,m in,max,tic:real;name:string);

This procedure draws an axis with tic marks and optionally labels each mark and writesthe name of the axis. Its parameters are:

px.py: the origin of the axis in inches.ieng: the length of the axis in inches. If leng is negative, no labeling of tic marks

or axis will be done,theta: angle of the axis with respect to the x direction in degrees,min: value of tic mark at origin.

max: value of outer end of axis (these two values are used to calculate the labelsof the tic marks).tic: frequency of tic marks on axis (eg: if tic = 5, tic marks will occur every 5units on the axis). If tic is negative, the labels will occur on the counter-clockwise side of the axis; otherwise, they will be on the clockwise side,name: string variable containing the name of the axis.

PLOTARRAY (nopoints,freq,sym:integer;px,py,xmin,xmax,ymin,ymax,height,xlen,ylen:real;var x.yxoord);This procedure plots an array of x and y coordinates. Its parameters are:nopoints: Number of points to be plotted.

Frequency of identifying symbol (0 = no symbols, 1 = every point, 2 = every

other point, etc). If freq is negative, only the points will be plotted with no in-terconnecting lines.

Identifier of symbol to be plotted at points:

sym = 1:triangle.

sym = 2:X.

sym = 3:square.

sym = 4: + .

sym = 5:vertical line.

Coordinates of origin of array plot.

Minimum value of variables.

Maximum value of variables.

Height of symbols in inches.

Size of area to be plotted.

Variables of type coord (no more than 256 points) to be used in the plot;

coord is a type that is predefined in the plotter subroutines and may be used

in the 'var' section of your program.

freq:

sym:

px,py:

xmin,ymin:

xmax.ymax:

height:

xlen.ylen

x,y:

Table 1: Summary of procedures and parameters from the Pascal unit "plotter".

216 October 19S1 © BYTE Publications Inc

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From this discussion you can seethat the unit makes the following pro-cedures available to the using pro-gram: plotline, plotsymbol, plot-string, plotwhere, plotarray, andplotaxis. (See table 1 on page 216.) Italso makes the definition of the type"coord" available to the using pro-gram. In fact, if the procedure"plotarray" is going to be invoked, avariable of the type "coord" must bepassed as a parameter to it.

The basic plottingalgorithm in all of theplotter procedures isexpressed in the pro-cedure "plotline".

Basic Plotting Procedures

Now that you're familiar with howthe unit interfaces to the using pro-gram, let's see how the various pro-cedures accomplish their tasks andhow the unit is put together. As youmight imagine, the construction ofthe unit after the implementation andinterface sections is simply a series ofPascal procedures with no programbody. If we did not want to makethese procedures into a unit, we couldsimply incorporate them into a Pascalprogram as normal procedures.

The Hiplot plotter can move its penin eight directions. These are left,right, forward, backward, and thefour moves at 45° (see figure 1). Inaddition, we have the pen-up andpen-down movements. With these tenmovements, the plotter is capable ofgrand and wondrous things.

The most fundamental procedurein the program is the machine-language procedure "plotstep" (seelisting 3). The purpose of this pro-cedure is simply to take the elemen-tary pen-movement commandspassed to it and send them to the plot-ter port. (The pen-movement com-mands are the letters p, q, r, s, t, u, v,w, y, and z sent to the plotter througha serial port.)This procedure waswritten to operate on a Z80-basedcomputer running at 2.5 MHz withthe plotter set to 0.005 inches perstep. Because of this, the timing loopsmight have to be adjusted to allowthe procedure to operate correctly ona different machine.

The operation of procedure

218 October 1981 © BYTE Publications Inc

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"plotstep" is straightforward: it sim-ply receives the plot command fromthe Pascal system (passed on the sys-tem stack along with the return ad-dress) and checks the status of theplotter (bit 1, port hexadecimal 7D in

this case). It then checks to see if thecommand is a pen-up or pen-downcommand, or a pen-movement com-mand. In each case, it takes ap-propriate timing action dependingupon the pen movement requested. If

BASIC PLOTTER DIRECTIONS

Figure 1: Basic plotter directions available to the Houston Instrument Hiplot. Thisdrawing was made by the Hiplot plotter.

the Pascal running on your systemincludes the logical device "REM-OUT:", the plotter could be attachedto the port addressed by "REMOUT:"and the plotting commands issued tothe plotter through that port.

Once this machine-language sub-routine is edited and assembled, it is asimple matter to use the linker to in-corporate it into a Pascal program asan external procedure or to store it inthe system library for use in the "plot-ter" unit.

The basic plotting algorithm in allof the plotter procedures is expressedin the procedure "plotline". Thisalgorithm is simply passed a para-meter ("penpos") that tells it whetherthe pen move is to be made with thepen up or down, and the endpoint ofthe next line to draw. It thencalculates the best straight-line fitfrom the current position of the pen("xpos" and "ypos") to the pointselected ("xplot" and "yplot"). Withthe pen either up (penpos = 1) ordown (penpos = 2), it draws the line.The algorithm used is simply a trans-lation of the BASIC algorithm sup-plied by Houston Instrument withthe plotter into Pascal.

A special case of "plotline" occurswhen penpos = 0. In this case, the penis assumed to be at the lower-left cor-ner of the plotter bed, and the var-iables "xpos" and "ypos" are init-ialized to that point. The machine-language subroutine "plotinit" is ex-ecuted during this initialization. Theprocedure simply initializes the serial

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output port to 9600 bps (bits per sec-ond) to make it compatible with thedata-input rate of the plotter (seelisting 4). "Plotline" with the penposof 0 must be executed before any plot-ting can be done with the other pro-cedures. In each case of a pen move-ment, procedure "plotline" checks tomake sure that a plot off the bed ofthe plotter is not being attemptedand, if so, reports this to the consolerather than attempting the plot.

The procedure "plotstring" usesprocedure "plotchar" to draw char-acters on the plot. Procedure "plot-string" is passed the starting locationof the lower-left corner of the firstcharacter to be plotted, the height ofthe characters (which should be amultiple of 0.035 to give the best-formed characters), the angle (indegrees relative to the long axis of thepaper) at which the string is to beplotted, and a string of characters tobe plotted.

The way in which the charactersare plotted is interesting. I decidedthat I had to develop an interpreterfor plotting the various pen moves.Plotting any character, I concluded,

would be a combination of straightlines in the fundamental directionsavailable on the plotter.

Rather than simply using "plotline"to do all the moves for each char-acter, the moves to plot each char-acter are generated in a coded formusing two vector pads made up oftwo groups of keys on the keyboard.One vector pad represents moveswith the pen up and the other withthe pen down. The letters d, w, a, andx are used for moves in the indicateddirections with the pen up, and 7, 8,9, o, 1, k, j, and u for moves in the in-dicated direction with the pen down.The length and direction of eachmove are determined by the heightand orientation of the character to beplotted. As you can see in the listingof "plotchar", each character is codedas a series of moves terminated withthe character "i".

In operation, the procedure takesthe character passed to it, assigns thestring of moves to the string variablePLOT, then decodes that string into aseries of pen movements. A fewspecial cases need to be noted at this

Text continued on page 242

Listing 1: The Pascal unit "plotter". This unit, which can be used by other Pascal pro-grams, contains several routines that simplify the process of drawing lines andcharacters on the Houston Instrument Hiplot plotter.

unit plotter;

interface (*These procedures and types are available to using program*)

type

coord=array [1.. 250] of; real;procedure plotline(penpos:integer;xnlot,yplot:real);procedure plotsvmbol(sym:integer;height:real);procedure plotstring(px,py,height,theta:real;line:string);procedure plotwhere(var px,py:real);procedure plotarray(nopoints,freq,sym:integer,•

t>x,py, XTtiin , XTnax,ymin ,ymax,

height,xlen,vlen:real;var x,y:coord);procedure plotaxis(px,py,leng,theta,min,max,tic:real;

name rstring);

implementation (*Kverything else is local to the unit*)

const

pi=3.14159;

screenwidth=79;

screenheight=23;var

clear:char;

a:array[1..16] off char;

xpos,ypos:real;

procedure plotstep(steprchar) ;external;

procedure plotinit; (*sets up usart for plotter*)external;

orocedure plotline;var

z,x,y,f,d,i,t,e:intener;

procedure initplot;begin

Listing 1 continued on page 224

222 October 1961 © BYTE Publications Inc

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Listing 1 continued:

clear:=chr (26);

write (clear);

gotoxy((screenwidth-47) div 2,screenheight div 2-1);

write('Please type [ret] when plot pen is at the lower');

qotoxy((screenwidth-26) div 2,screenheight div 2);

write('left corner of plotter bed');

readln;

write(clear) ;

plotinit;

xpos:=0.0;

ypos:=0.0;

a[l] : = 'p';a[2] : = 'q';a[3] : = ,r';a[4] : = 'q';a[5] : = 'r';a[6] :a [7] :='t';a[8] : = 's';a[9] : = 't';a[10] :='u';a[ll] :='v';a [12] : = 'u';a[13] : = 'v',-a [14] :='w';a [15] : = 'p' ;a [16] : = 'w' ;plotline(l,0,0);end; (*initplot*)

begin(*plotline*)case penpos of0:initplot;l:plotstep('y') ;2:plotstep ('z') ;end;

if penpos=0 then exit (plotline);

if (xplot>10.25) or (xplot<-0.25) or (yplot>7.25)or (yplot<-0.25) thenbegin

write(clear);

gotoxy((screenwidth-49) div 2,screenheiqht div 2-1);

writeln('Plotline: Plot attempted off paqe ('

,xplot:6:2,',',yplot:6:2,')');gotoxy((screenwidth-17) div 2,screenheight-l);write ('Please type [ret]');readln;write(clear);exit(plotline);end;x:=round((xplot-xpos)*200);y :=round ( (yplot-ypos)*200);xpos:=xpos+x/200 ;ypos:=ypos+y/200;

(*This section is translated from Houston Instrument *)

f:=abs(x)+abs(y);if f=0 then exit(plotline);d:=abs(y)-abs(x);i:=0;

if y>=0 then i: = 2;t:=x+y;

if t>=0 then i:=i+2;t:=y-x;

if t>=0 then i:=i+2;if x<0 then i:=i-H0else i:=8-i;if d<0 then t:=abs(y)elsebegin

t:=abs(x);d:=-d;end;e:=0;repeat

z:=t+d+e+e;

if z<0 then

begin

e:=e+t;

f:=f-l;

plotstep(a[i-1]);endelsebegine:=e+d;f:=f-2;

plotstep (a[i]);end;until f< = 0;end;(*plotline*)

procedure plotstring;var

stepl,xstepl,ystepl,x2stepl,y2stepl,x3stepl, y.3stepl,step,xstep,ystep,x2step,y2step,x3step,y3step:real;j,n:integer;

procedure plotchar (oil :char) ;var

rxpos,rypos:real;

's';

Listing 1 continued on page 226

224 October 1981 © BYTE Publications Inc

TM

APPLEPASCAL

A HANDS-ON APPROACH

Learn to use the mostpowerful language your vvcomputer can have.

This "hands-on" methodgives you all the working skillsyou need to create, run, anddebug programs in Pascal onthe Apple II or Apple II Plus.

Detailed program examplesand practical, step-by-stepexercises on the computer it-self lead you from funda-mentals to such advancedtopics as programming style,

Also available:

tends-

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'X&Z22?

data structures, top-down vs. bottom-up design,scalar data types, andrecursion.

No math background isrequired. Users learn full editorand operating features as wellas the Pascal language—thisis the only complete guide to

M

BASIC: A HANDS-ON METHOD, 2/eHerbert D. Peckham

320 pages, $12.95 Spiral bound

Immediate application of concepts as they areintroduced allows you to quickly become profi-cient in BASIC programming. For use withnumerous time-sharing and personal computers,this book emphasizes hands-on experience.

PROGRAMMING BASIC WITH THE TlHOME COMPUTER

Herbert D. Peckham

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The only complete guide to programming inBASIC on the Tl Home Computer. All informationis presented using a hands-on method whichrapidly builds programming skills.

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This acknowledged classic provides a highlyhelpful guide to effective, efficient programmingfor a wide range of tasks. Includes numerous ex-amples and a set of 'rules' of good programming.

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ORDER A CATALOGLISTING ALL SAM'SBOOKS AND SAVEWITH SPECIAL DIS-COUNT PRICES D/

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Prices may be subject to change without notice.

Listing 1 continued:

plot:strinq[32];pchar:char;i:inteqsr;

procedure arrow;

begin

stepl:=0.04;xstepl:=stepl*cos(ystepl:=stepl*sin(x2stepl:=sqrt(2)y2stepl:=sqrt(2)x3stepl:=sqrt(2)*sy3stepl: ~sqrt (2) *splotline(2,xpos-y2plotline(2,xpos+ysplotline(2,xpos+ysplotline(2rxpos-yexit(plotchar);

end; (*arrow-)

procedure getcode;begin

case ch of

theta);theta) ;

tepl*cos (theta+pi/4tepl*sin (theta+pi/4tepl*cos (theta--pi/4tapl*sin (thet.a-pi/4stepl,ypos+x2stepl)tepl,ypos-xstepl);tepl,ypos-xstepl) ;stepl,ypos+x3stepl)

'A'■B'

*c

'D'■E'

• p.

'G''H''!■•J'•K'

•l'

• M'■N"•O1ipi

■0''R'

'S'

1 rp I

'u'•v

'W1

■X'

lYl

■z"

• >>

11 ■

endend;(*g

plot:='d8 8 88 8 89oolkkkkkkaaaawwwwooooi';

plot:='d888 8888ooolkjuuuooolkkjuuui';

plot:='dddddwjuu7888889ooli';

plot:='d88888 88ooolkkkkkjuuui';

plot:='ddddduuuu8 8 8 8oouu8 8 8ooooi';

plot:='d8888oouu888ooooi';

plot:='dddddwwwwww7uujkkkkkloo988uui' ;

plot: = 'd8888383ddddkkkkkkkwwwuuuui' ;

plot:='doooouu8888888uuooooi';

plot:='dwloo9888888i';

plot:='d8888888dddjjjlllli' ,-

plot:='ddddduuuu8888888i';

plot:='d88 8888811kk8899kkkkkkki';

plot:='d88888881111wwwwkkkkkkki';

plot:='dd7 888889oolkkkkkjuui';

plot:='d88888B8ooolkkjuuui';

plot:='dd788 8 8 89oolkkkkkjuudwwlli';

plot:='d8 8 88888ooolkkjuuuooolkki';

plot:='dwloo9R8 7uu7 8 9ooli';

plot:='ddd88888 8 8aaooooi';

plot:='dwwwwwwwkkkkkkloo9888888i' ;

plot:='dwwwwwwwkkkkkll9988888i';

plot: = 'dwwwwwwwkkkkkkk9988kkll8888888i' |

plot:='d8899998aaaakllllkki';

plot:='dwwwwwwwkll99 8kjjkkkki';

plot:='dwwwwwwwooookjjjjkkooooi';plot:='ddd8okui';plot:='ddwwoooowwuuuui';plot:='d999777i';plot:='dddd777999i';plot:='dwwooo97uu79ooowaakkkkkki';plot:='oooooooIi';(*case*)etcode*)

procedure getcode2;begincase

V

end

end;(*g

ch of:plot:plot:plot:plot:plot:plot:plot:plot:plot:plot:plot:plot:plot:plot:plot:plot:plot:plot:plot:plot:plot:plot:plot:plot:plot;(*case*)etcode2*)

' dww9999aakkkkdd7777xxooooi';

'd8899998i';

'dw9999aaaku8oxxxxd8ok8okuui';

'ddd8w8997uujki';

'ddddwwwwwSokui';

'dddwwwwkkuu8 8ooooxaooakki';

'ddd8okuoji *;

'dwwwww99kkkkkkkuuooooi';

1 dwwwwww9oolkkj j j jooooi ' ;

1dwwwwww9ooojjjoolkkjuu7i' ;

'dwwwwwwwkkkkooooawwwwkkkkkkki';

1 ddddd\^^wwwwwuuuukkkooolkkiuu7i ' ;

1dddddwwwwww7uujkkkkkloo9887uuji ' ;

'dwwwwww8ooookjjkkkki1;

1ddwwww7B9oolkjuujkkloo9 8 87i';

'dwloo9888887uujkkloo9i';

•dd7888389oolkkkkkjuui';

'dddd7788899i*;

'dd9988877i';

'dw9999aaauko8xxxxddo8uki';

1dddww8888aaxxooooi';

'dwwwwooooi';

'ddwwo8ukwwo8uki';

1 li' ;

'2i' ;

Listing 1 continued on page 228

226 October 1981 © BYTE Publications Ire

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BYTE October 1981

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Listing 1 continued:

beqin(*plotchar*)rxpos:=xpos;rypos:=ypos;Dlot: = 'i' ;qetcode;qetcode2;i:=l;

pchar•='0';while pcharo'i' dobeqin

pchar:-plot[i];case nchar of

'd':nlotline(l,xpos+xstep,ypos+ystep);

1 w1 :n lot line (1 ,xpos-ystep,ypos+xster>) ;

'a':olotline(1,xpos-xstep,ypos-ystep);

1 7 ':plotline(2,xpos-x3step,ypos-y3step);

' 8 ':plotline(2,xpos-ystep,ypos+xstep);

'9' :plotline(2,xpos+x2step,ypos+y2steo) ;

1o':plotline(2,xpos+xstep,ypos+ystep);

11':plotline(2,xpos+x3step,ypos+y3step)

'k'rplotline(2,xpos+ystep,ypos-xstep);

'j' :plotline(2,xpos-x2step,ypos-y2step) ;

'u':plotline(2,xpos-xstep,ypos-ystep);

'x' rplotline(1,xpos+ystep,ypos-xstep);

' I ' sarrow;

:beqinrxpos:

=rxpos-(heiqht/2)*sin(theta) -6*xstep;rypos:=rypos+(heiqht/2)*cos(theta) -6*ystep;end;12' :beqin

rxpos: = rxpos+(heiqht/2)*sin(theta) -

6*xstep;rypos:=rypos-(height/2)*cos(theta)-6*ystep;end;end;(*case*)i:=i+l;end;(*while*)

plotline (l,rxpos+6*xstep,rypos+6*ystep);end; (*plotchar*)

beqin(*plotstrinq*)

theta:=(theta/360)*2*pi;

step:=height/7;

xstep:=step*cos(theta);

ystep:=step*sin (theta);

x2step:=sqrt(2)*step*cos(theta+pi/4)

y2step:=sqrt(2)*step*sin(theta+pi/4)

x3step:=sqrt(2)*step*cos(theta-pi/4)

y3step:=sqrt(2)*step*sin(theta-pi/4)

n:=lenqth(line);

plotline(l,px,py);

for j:=1 to n doplotchar (line (j]);end; (*plotstring*)

procedure plotvar

rxpos,rypobeqin

rxpos:=xpo

rypos:=ypo

case sym o

1:beqin

Plot

plot

plot

plot

plot

end;

2:beqin

plot

plot

plot

plot

plot

end;

3:beqin

plot

plot

plot

plot

plot

plo

plo

end;

4 rbegin

symbol;s rreal;

*trianqle*)line (2,xpos,ypos+heiqht/2);line (2,xpos-heiqht/2,ypos-heiqht);line (2,xpos+heiqht,ypos);line (2,xpos-heinht/2,ypos+heiqht);line (1,rxpos,rypos);

(* X *)

line(l,xpos-heiqht/2,ypos+heiqht/2);

line (2,xpos+heiqht,ypos-heiqht);

line (l,xpos-heiqht,ypos);

line(2,xpos+heiqht,ypos+heiqht);

line(1,rxpos,rypos);

(*square*)

line(2,xpos,ypos+height/2);

line(2,xpos-height/2,ypos);

1 i np f? vnnc ynnc-hoi nhf1 -

line (/. ,xpos-neiqnt/^ ,yposline (2,xpos,ypos-height);line (2,xpos+height,ypos);:line(2,xpos,ypos+height);>tline(2,xpos-height/2,ypoitline(1,rxpos,rypos);

'S):

Listing 1 continued on page 230

228 October 1981 © BYTE Publications Inc

■TM

THE FORTH SOURCE

Specializing in the FORTH Language.

MANUALS & GUIDES

D "Starting FORTH" by Brodie. Prentice-Hall. Best User's manual available (soft cover)

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□ "Proceedings, 1981 Rochester University FORTH Conference." Technical papers.D "METAFORTH" by Cassady. Cross-compiling, 8080 source code.

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□ H89/Z89 by G. Haydon, fig-FORTH, stand alone, source listing, editor, assembler, screens and tutorial on disk (3-5'A")D H89/Z89 by G. Haydon, fig-FORTH, under CP/M", source listing, editor, assembler, screens and tutorial on disk (3-5Vt")D TRS-80/1* by Nautilus Sys. fig-FORTH, editor and assembler (1 -5'A")

D TRS-80/I or III* by Miller Microcomputer Services. MMSFORTH, editor, assembler interpreter/compiler, virtual memory. (1.-5V4")

□ NOVA* by Ting. fig-FORTH, editor, assembler, source listing and screens. (1 -8")

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Special Function FORTH Systems with manuals

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D CP/M* D H89 D TRS-80/I* □ Northstar

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D Z-80* Program Development by Laboratory Microsystems with full software floating point arithmetic.

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NEW!!! THE *

ELECTRIC MOUTH

for S l(H), Elf II, Apple, TRS-80 Level II

From $99.95 kitNow— teach your computer totalk, dramatically increasingthe interaction between youand your machine.

That's right: the ELECTRIC MOUTH actually letsyour computer talk! Installed and on-line in justminutes, it's ready for spoken-language use in office,business, industrial and commercial applications,in games, special projects, R&D, education, secu-rity devices — there's no end to the ELECTRICMOUTH's usefulness. Look at these features:

* Supplied with 143 words/letters/ phonemes/numbers, capable of producing hundreds of wordsand phrases.

* Expandable cm-board up to thousands of wordsand phrases (just add additional speech ROMs asthey become available}.

* Four models, which plug directly into S100. Apple,Elf II and TRS-80 Level II computers.

* Gel it to talk by using either Basic or machinelanguage (very easy to use. complete instructionswith examples included).

* Uses National Semiconductor's "Digitalker"system.

* Includes on-board audio amplifier and speaker,with provisions for external speakers andamplifier.

* Adds a new dimension and excitement to pru-gramming; lets you modify existing programs andgames to add spoken announcements of results.warnings, etc.

* Installs in just minutes.

Principle of Operation: The ELECTRIC MOUTHstores words in their digital equivalents in ROMs.When words, phrases, and phonemes are desired,they are simply called for by your program and thensynthesized into speech. The ELECTRIC MOUTHsystem requires none of your valuable memoryspace except for a few addresses if used in memorymapped mode. In most cases, output ports (userselectable) are used.

Spoken Material Include^

one

eighteen

ni

dollar

inches

number ss

r

two

three

twenty

case

equal

il

off set

four

cent

kilo

five

forty

•lOOhertz lone

left

„

SIX

flOlierlz lone

less

si; von

sixty

20ms silence

IfSMT

RIRhl

40ms silence

gallon

li.mil

percent stop

i

nine

80 ms silence

ten

ninety

160ms silence

lower

plus the

hundred

;i20ms alienee

twelve

ihousiind

centi

greater

mciiT

.

thirteen

million

check

mile

pulses up

n

fourteen

zero

comma

mi Hi

_

fifteen

again

control

higher

minus

9,

sixteen

ET"

Hanger

hour

minutf

ready a

seventeen

degree

in

near

right 1)

s

""El/ II" and "The Electric Mouth" are res. trademarks ofNelronics R&D Lid. "Apple" is a reg. trademark of AppleComputer Inc. "TRS-80 Level 11" is a reg. trademark of TandyCorp.

Conllnemal U.S.A. Credit Card Buyers Outside Connecticut

CALL TOLL FREE 800-243-7428

To Order From Connecticut Or For Technical Assistance, Etc.,

Call (203) 354-9375

NETRONICS R&D LTD.DePtBo

333 Litchfield Road, New Milford, CT 06776

Please send (he items checked below:

D S100 "Electric Mouth" kit $99.05

□ Elf II "Electric Mouth" kit $09.95

□ Apple "Electric Mouth" kit $l 19.95

□ TRS-80 Level II "Electric Mouth" kit $119.95

Add $20.00 for wired & tested units. All plus $3.00 postage & in-surance. Conn res. add sales tax.

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Listing 1 continued:

plotline(2,xpos

plotline(2,xpos

plotline(2,xpos

plotline(2,xpos

plotline(2,xpos

plotline(2,rxpo

end;

5:begin ('vertical

plotline(2,xpos

plotline (2,xpos

plotline(2,rxpo

end;

end; (*case*)

end; (*plotsymbol*)

procedure plotwhere;beqin

px;~xpos;PY:=ypos;

end;

procedure plotarray;var

pen,i:integer;begin

if nopoints>250 thenbegin

write(clear);gotoxy ( (screenwidth-writeln{'Plotarray:gotoxy((screenwidth-write('Please type [readIn;write(clear);exit(plotarrav);end;if (py+ylen>7.0) or (px+begin

write(clear);gotoxy((screenwidth-writeln('Plotarray:px+xlen:6:2,',', py+ygotoxy((screenwidthwrite ('Please typereadln;write (clear);exit(plotarray);end;xlen:= (xmax-xmin)/xlen;ylen:= (ymax-ymin)/ylen;if freq<0 then pen:=lelse pen:=2;freq:=abs (freq);plotline(1,((x[1]-xmin)/if freq>0 then plotsymbofor i:=2 to nopoints dobegin

plotline (pen,((x[i]-( (y ti]-ymin)/ylen)if (freq>0) then

if ((i+1) mod freqend;end; (*plotarray*)

+height/2,ypos);

height,ypos);+height/2,ypos),ypos+height/2);,ypos-height);s,rypos) ;

line*)

,ypos+height/2) ;,ypos-height);s,rypos);

42) div 2.screenheight div 2);Plot attempted with >250 points')17) div 2,screenheight-l);ret] ' ) ;

xlen>10) then

50) div 2,screenheiqht div 2-1);Plot attempted off page (',len:6:2, ' ) ' ) ;

17) div 2,screenheight-l);retl');

xlen) +px, ( (y [1] -ymin) /ylen) -i-py) ;1 (sym,height);

xmin)/xlen)+px,+PY) ;

:0) then plotsymbol(sym,height)

procedure plotaxis;var

tempi,side:integer;

print:boolean;

amount:string;

thetal,temp,rxpos,rypos,len,per,step rreal;

procedure divsteps(theta:real);

begin

theta:=theta+pi/2;

plotline (2,xpos+0.03*cos(theta),ypos+0.03*sin(theta))plotline(2,xpos-0.06*cos (theta),ypos-0.0 6*sin(theta))plotline(2,xpos+0.0 3*cos(theta),ypos+0.0 3*sin(theta))

end;

begin(*plotaxis*)if tic<0 thenbegin

tic:=-tic;side:--1;endelse

side:=1;thetal:-theta;theta:= (2*pi/36f)) *thet.i ;

Listing 1 continued on page 232

230 October 1981 © BYTE Publications Inc

If you've ever missed a deadline,forgotten an appointment, waited on latedeliveries or lost track of projects, putANGEL to work for you.

ANGEL is the new software programfor microcomputers that helps organizeand manage your business flow. It'sstrictly business.

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WORKS FOR ANY BUSINESS

You can custom-program ANGEL forany business operation — from oil

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With a memory capacity that's limitedonly by the capacity of your disk storage,ANGEL tracks multiple projects for busyexecutives. The disk comes with aneasy-to-understand printed manual, toback up the built-in set of instructionsof the program itself.

In addition, a data-proof safeguardsystem will not let you accidentallyerase entries, and a special passwordcode of your choice allows you to keepconfidential files.

Put ANGEL to work for you today.You'll never lose track of your workflow again.

ANGEL is recommended for use withany disk-based system that has 48kmemory or more. It will operate withany CP/M*-based system and theTRS 80*" (Model I, II or III). The

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NAME .

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Price includes tax, handling and shipping (except C.O.D. orders)

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* Registered trademark of Digital Research, Inc.** Registered trademark of Tandy Corp.

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Listing 1 continued:

if (px+leng*cos(theta)>10) or (py+lenq*sin(theta)>7) thenbeqin

writeln{'Plotaxis: plot attempted off page (',

px + lenq*cos(theta) ,',',py + leng*sin(theta) ,')');write('Please type [ret] ') !readln;

exit(plotaxis);end;if leng<0 thenbegin

print:=false;leng:=-leng;endelse

print:=true;len:=leng;plotline(1,px,py);per:=(leng-0.01)/(max-min);while leng>0 dobegin

if leng>tic*per then step:=tic*perelse step:=leng;divsteps(theta);if print thenbegin

rxpos:=xpos;rypos:=ypos;tempi:=trunc(min*10 0);str(tempi,amount);

insert('.',amount,length(amount)-1);temp:=length(amount)/2;

plotline(l,xpos-(0.0 86*temp*cos(theta)-side* (0.14+(side-l)*0.0 5)*sin(theta)),ypos- (0.0 86*temp*sin(theta)+side*(0.14+(side-1)*0.05)*cos(theta)));

plotstring(xpos,ypos,0.1,thetal,amount) ;plotline(1,rxpos,rypos);end; (*if*)plotline(2,xpos+step*cos(theta),ypos+step*sin(theta));leng :=leng-step;min:=min+tic;end;(*while*)if print thenbegin

plotline(1,

xpos-(len/2*cos(theta)+0.108"round(length(name)/2)

*cos(theta)-side*(0.35+(side-1)*0.075)*sin(theta)),ypos-(len/2*sin(theta)+0.108*round (length(name)/2)

*sin(theta)+side*(0.3 5+(side-1)*0.075)*cos(theta)));plotstring (xpos,ypos,0.125,thetal,name);end;end;(*plotaxis*)end.(*unit*)

Listing 2: A demonstration Pascal program that uses the "plotter" unit. The plot drawnby this program is shown in figure 3.

program plotter_demo;uses plotter;

const

pi=3.14159;

var

index:integer;

xpoints,sinypoints,cosypoints:coord;

xloc,yloc,angle:real;

begin

(*this segment initializes the arrays*)

for index:=l to 250 dobegin

angle:=(index-1)/2 4 9*2*pi;

xpoints[index]:=index-l;

sinypoints[index]:=sin(angle);

cosypoints[index]:=cos(angle);end;

(*this segment does the plotting*)

plotline(0,0,0);

plotstring(3,6.75,0.126,0,'this is a demonstration of the plotter unit');

plotaxis(0.5,0.5,9.5,0,0,36,6,'angle (in degrees) *10[-1]');

Listing 2 continued on page 238

232 October 1981 © BYTE Publications lnc

SOFTWAREGURU

You've been looking for a softwaresource to help with your programming. This month BYTEBOOKS features four editions for your thoughtful consideration. Aprogramming guide-book on the 6502,compact threaded lan-guages for the Z80,and two volumes onscientific subroutines.Enough to challenge anyhobbyist or scientist.

These books won't turn youinto a Software Guru — but they willhelp you think like one!

Blill

BIKMS

m

Sgss^g*

BttAINS, BEHAVIOR

&

ROBOTICS

tame» & Albus

:'""osr w

Kent (2

AVAILABLE FALL 1981

DIGITAL HARMONY

by John Whitney

A new synthesis ofsight and sound

Digital Harmony lays thefoundation for the whole newfield of audio-visual art madepossible by microcomputers.John Whitney, a pioneer of thespecial effects technologyused in STAR WARS and 2001:A SPACE ODYSSEY, explains thespecial union of computergraphics and music. Hiscomputer-generated visualart graphically depicts thelaws of harmonic motioncommon to all music.

Digital Harmony includes acomplete description ofWhitney's computer, periph-erals, and film techniques.Colorful illustrations are in-cluded, as well as the programlistings that generated them.The descriptions are sufficientfor anyone to begin to explorethis new territory as a com-poser and computer experi-menter - transforming the smallcomputer into an ideal instru-ment for creating compositionsin aural and visual art.

John Whitney is on theFaculty in the Departmentof Art at the University ofCalifornia, Los Angeles.

ISBN 0-07-070015-X

240 pages

hardcover

over 50 color £01 Qf%

photographs 9 dm I ■ r 9

INVERSIONS:A Catalogue ofCalligraphicCartwheels

by Scott Kim

Foreword by Douglas Hofstader

Backword by Jef Raskin

Surprising symmetries indesign and letterforms

Illusion . . . calligraphy ...visual magic - Scott Kim's newbook, Inversions, delights theeye and enchants the mind.Fiiled with intriguing designs,words that read the same right-side up and upside down,words within words, and un-expected symmetries, thesecompositions create a freshway to look at the alphabet.The text includes the visualprinciples of symmetry, lettering,and problem solving that arebasic to these images. Theauthor also draws parallels torelated exercises in perceptionin such diverse areas as art,music, word play, and mathe-matics. Scott Kim's originalinversion designs first appearedin Omni magazine, inspiringan overwhelming reader re-sponse. An irresistable chal-lenge, invertible writing appealsto everyone who loves beautyin mathematics and design.

Scott Kim is a doctoral studentin Computer Science at Stan-ford University and is a concertpianist and composer.

ISBN 0-07-034546-5

128 pages

softcover

over 50 illustrations

available summer 1981

$8.95

BRAINS,BEHAVIOR,AND ROBOTICS

by James S. Albus

Robotics designand applications

This computer-oriented guideexplores how the brain functionsprimarily as a computer devicefor generating and con-trolling behavior. The authorassesses behavior as a productof three hierarchies ofcomputing modules:

• memory modules

• behavior-generating modules

• sensory-processing modules

A section on artificial intelli-gence ties this hierarchicalmodel to vital computerscience techniques such asplanning, problem-solving,machine vision, naturallanguage understanding andknowledge representation. Aclosing section on roboticsdiscusses the design consid-erations in constructing a robotcontrol system fashioned afterthis model of the brain, andexplores the current andpotential use of robots inour environment.

Dr. James S. Albus is ProjectManager with the NationalBureau of Standards.

ISBN 0-07-000975-9400 pageshardcoverISO illustrations

$16.95

THE BRAINS OFMEN AND MACHINES

by Ernest W. Kent

Human models forcomputer design

When the "Brains of Men andMachines" series of articlesfirst appeared in BYTEmagazine, the response wasimmediate and enthusiastic.Now Ernest W. Kent has expand-ed his ideas about the braininto a full-length book. Asresearchers begin to unravelthe mysteries of the brain'schemical, electrical, andsynaptic circuitry, their findingsare becoming immediatelyapplicable to advances inrobotic behavior and computerdesign. The Brains of Men andMachines "dissects" the brainto provide new insights intocomputer design and artificialintelligence.

It is one of the rare books thattranscends disciplinary bound-aries. In it the ever-increasingrelationship between man andmachine is freshly examined -a relationship. Professor Kentconcludes, that is today beingreexamined in the light ofman's own neurologicalself-image.

Dr. Ernest W. Kent is aProfessor of PhysiologicalPsychology and Psycho-pharmacology at the Universityof Illinois at the ChicagoCircle Campus.

ISBN 0-07-034123-0

304 pages

hardcover aib ft C

illustrated ^lO.YO

The BYTE BOOK Collection

Circle 51 on inquiry card.

BASICSCIENTIFICSUBROUTINES,VOLUMES1 AND 2

■ '-■' :V'^-^>'

UAStCSciei»(i/ir

-..,;,, ,, ,. Vol.

by Fred Ruckdeschel iSI

Valuable programs forprofessional and hobbyist

Designed for the engineer, scientist,experimenter, and student, this series pre-sents a complete scientific subroutinepackage in BASIC.

• Volume 1 covers plotting, complex vari-ables, vector and matrix operation,random number generation, and seriesapproximations.

• Volume 2 continues with least-squaresapproximation, special polynomialfunctions, approximating techniques,optimization, roots of functions, inter-polation, differentiation, integration, anddigital filtering.

These volumes feature routines written in bothstandard Microsoft and North Star BASIC,extensive appendices, and subroutinecross-referenes.

Dr. Fred Ruckdeschel is a PrincipalScientist with Dynacomp. Inc.

VOLUME 1 VOLUME 2

ISBN 0-07-054201-5 ISBN 0-07-054202-3336 pages 384 pages hardcover

hardcover illustrated

illustrated available Fall 1981

$19.95 J23.95

«■ BYTE Boofco*

Pascal THE BYTE

BOOK

„_—» PASCAL

Blaise W. Liffick, Editor

A powerful, structured language

Based on articles, language forums, andletters from BYTE magazine, this work is avaluable software resource. Pascal con-tinues to be popular as a structured pro-gramming language. Written for bothpotential and established users, this bookintroduces the Pascal language andexamines its merits and possible imple-mentations. Featured are two versions of aPascal compiler, one written in BASIC andthe other in 8080 assembly language;a p-code interpreter written in both Pascaland 8080 assembly language; a chess-playing program; and an APL interpreter.

ISBN 0-07-037823-1334 pageshardcover

$25.00

THREADED

INTERPRETIVE

LANGUAGES

by Ronald Loeliger ,

How to implementFORTH on your Z80

Threaded languages (such as FORTH) arecompact, giving the speed of assemblylanguage with the programming ease ofBASIC. They combine features found in noother programming languages. This bookdevelops an interactive, extensiblelanguage with specific routines for the ZilogZ80 microprocessor. With the core inter-preter, assembler, and data type definingwords covered in the text, it is possible todesign and implement programs for almostany application and equivalent routinesfor different processors.

Ron Loeliger is a Senior Analyst withIntermetrics, Inc

ISBN 0-07-038360-X272 pageshardcoverillustrated

$18.95

BEGINNER'SGUIDE FORTHE UCSDPASCALSYSTEM

by Kenneth L. Bowles

The most popular Pascalversion explained by its creator

Written by the originator of UCSD PascalSystem, this informative book is an orienta-tion guide to the UCSD Pascal System. Forthe novice, this book steps through theSystem, bringing the user to a sophisticatedlevel of expertise. Once familiar with theSystem, the reader will find the guide aninvaluable reference tool for creatingadvanced applications. The package offersprograms which may be run withoutalteration on:

• DEC PDP-11 or General Automationminicomputers

• Western Digital Microengines

• 8080, 8085, Z80, 6502. 6800, 9900 orAM-lOO based microcomputers (includ-ing the popular Apple II and Radio ShackTRS-80 microcomputers)

Dr. Kenneth L. Bowles is Director of theInstitute for Information Systems, Universityof California, San Diego.

ISBN 0-07-006745-7204 pagessoftcover

$11.95

, vat, svsr „

^ rtASovAt WHAT? I

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WHAT?

by Thomas Dwyer and Margot Crifchfield

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Intended for both the novice programmerand the experienced computer enthusiast,this book presents practical ideas forpersonal computer use at home or at work.

Its approach is especially suitable foreducational purposes. Written by theleading contributors of computer educa-tion material, this book is an entertainingand resourceful tool. There are over 60ready-to-use programs written in Microsoftand Level II BASIC for the TRS-80 in the areasof educational games, financial recordkeeping, business transactions, disk-based files, and word processing.

Dr. Thomas Dwyer is a Professor ofComputer Science at the University ofPittsburgh.

Margot Critchfield is a doctoral studentin Foundations in Education at the Univer-sity of Pittsburgh.

ISBN 0-07-018492-5343 pagessoftcover78 illustrations

$11.95

BEYOND GAMES:

SYSTEM

SOFTWARE

FOR YOUR

6502

PERSONAL

COMPUTER

by Kenneth Skier

Creating programs for the Apple,Atari, Challenger andPET computers

At last, a complete programming guide-book for owners of personal computersutilizing the 6502 microprocessor. A self-contained course in structures programmingand top-down design, this book presentsa powerful set of tools for building anextended monitor, disassembler, hexadec-imal dump routine, and text editor programs.Programs are thoroughly explained, withclear instructions for modifications

Kenneth Skier is a Systems Programmerfor Wang Laboratories, Inc., and a Lecturerat MIT.

ISBN 0-07-057860-5440 pagessoftcoverillustrated

$14.95

stimulating, provocative, problem-solving

Circle 52 on Inquiry card.

BYTE October 1981 235

CIARCIA'S

CIRCUIT

CELLAR

by Steve Ciarcia

Practical uses for home computers

Imaginative and practical, Ciarcia's CircuitCellar details a variety of microcomputerprojects. A collection of the best articlesfrom 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 are given on how toconstruct each project. With amusinganecdotes and an easy-going style,Ciarcia presents his material in such amanner that even a neophyte need not beafraid of it.

ISBN 0-07-010960-5

125 pages

softcover

color photographs and diagrams

$8.00

CIARCIA'SCIRCUITCELLAR,VOLUME II

by Steve Ciarcia

More practical uses forhome computers

Composed of popular articles from BYTEmagazine, this volume tells how micro-computers can be uniquely interfaced toour environment. Projects include

• building a computer controlled home-security system

• computerizing appliances

• transmitting digital information over abeam of light

• building the Intel 8O86 microprocessorsystem design kit

• input-output expansion for the TRS-8O

ISBN 0-07-010963-X

224 pages

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photographs and diagrams

$12.95

MICRO-COMPUTERSTRUCTURES

by Henry D'Angelo

Digital Electronics,Logic Design, andComputer Architecture

Today, there is an increasing demand forcomputer users who are not only well-versedin software, but who can also maintain,modify, and design their own hardwaresystems.

This text introduces computer users withlittle or no background in digital hardwareto the basic computer structures used inmicrocomputer design and microcomputerinterfacing. Helpful examples and end-of-chapter exercises further illustrate thevarious concepts presented, and a detailedbibliography provides additional readingopportunities. 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 Deanof the College of Engineering and Professorof Manufacturing Engineering at BostonUniversity.

ISBN 0-07-015294-2288 pageshardcover314 illustrationsavailable spring 1981

$18.95

Instructor's ManualISBN O-O 7-015298-5softcover

$8.95

BUILD

YOUR OWNZ8OCOMPUTER

by Steve Ciarcia

Every step spelled out fordo-it-yourself buffs

For the engineer, computer technician,student, and anyone interested in buildinga computer rather than buying one, thispractical guide shows how to build a work-ing computer based on the Zilog Z8O micro-processor. Each computer subsystem is fullyexplained and supported by proven designand testing information. The descriptionfocuses on a basic single-board micro-computer 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 meetpersonal needs.

Steve Ciarcia is a Computer Consultant,Electrical Engineer, and author of "AskByte" and "Ciarcia's Circuit Cellar" columnsin BYTE magazine.

ISBN 0-07-010962-1330 pagessoftcoveravailable summer 1981

$15.95

BYTE Books' reputation is basedon providing technicallyaccurate, useful, and timelyinformation. Established on thesame principle as BYTEmagazine, BYTE Book's evolvedin response to the rapidly ex-panding audience of homeand business computer users.Computer professionals andenthusiastic newcomers needto keep pace with thisunabated growth. This selec-tion of BYTE books canexpand your library of knowl-edge and expertise.

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Listing 2 continued:

plotaxis(0.5,0.5,5.75,90,-1,1,-0.5,'magnitude');

plotarray(250,-10,3,0.5,0.5,0,2 49,-1,1,0.07,9.5,5.7 5,xpoints,sinypoints);plotarray(250,10,2,0.5,0.5,0,249,-1,1,0.07,9.5,5.7 5,xpoints,cosypoints);plotline(l,5.5,6.25);plotsymbol(3,0.126);plotwhere(xloc,yloc);

plotstring(xloc+0.2 5,yloc-0.126/2,0.12 6,0,'- sine');plotline(l,5.5,5.75);plotsymbol(2,0.126);plotwhere(xloc,yloc);

plotstring(xloc+0.25,yloc-0.126/2,0.126,0,'- cosine');end.

Listing 3: The machine-language procedure "plotstep". This procedure, which is depen-dent on the hardware implementation given in the text, transmits pen-movement com-mands to the Hiplot plotter through its associated output port.

.PROC PLOTSTEP,

L

.PRIVATE PENPOS,RETADDR

STATUS

.EOU 0 7DH

PLOTCMD

.EQU 7CII

UPCMD

.EQU 79H

DNCMD

. EQU 7AH

UP

.EQU 0FFH

DOWN

.EQU OOH

POP HL

GET RETURN ADDRESS

LD (RETADDR), HL

LOAD RETURN ADDRESS

POP BC

GET CHARACTER

PLOTOUT

IN A,(STATUS)

INPUT STATUS

AND 1

MASK STATUS BIT

JP Z,PLOTOUT

WAIT FOR READY

LD A,C

GET PLOT CHARACTER

OUT (PLOTCMD),A

PLOT IT

CP UPCMD

PEN UP?

JP 7,, PENUP

YES, TIME IT OUT

CP DNCMD

PEN DOWN?

JP Z,PENDN

YES, TIME IT OUT

LD A,(PENPOS)

GET PEN POSITION

CP UP

UP?

JP Z,EXIT

YES, RETURN

LD B,00H

LOAD TIMER

LD C,B0H

LOAD TIMER

CALL TIMER

JP EXIT

RETURN

TIMER

DEC BC

DECREMENT TIMER

LD A,B

GET TIMER HIGH

CP OOH

ZEROED OUT?

JP Z,TIMER1

YES, TIME FURTHER

JP TIMER

NO, DO IT AGAIN

TIMER1

LD A,C

GET TIMER LOW

CP OOH

TIMED OUT?

JP Z,EXIT

YES, RETURN

JP TIMER

CONTINUE TIMING

PENUP

LD A,(PENPOS)

CHECK PEN POSITION

CP UP

UP?

JP Z,EXIT

YES, RETURN

LD A,UP

SET PENPOS UP

LD (PENPOS),A

PENPOS UP

LD B,02H

NO, TIME OUT

CALL TIMER

JP EXIT

PENDN

LD A,(PENPOS)

CHECK PEN POSITION

CP DOWN

DN?

JP Z,EXIT

YES, RETURN

LD A,DOWN

SET PENPOS DN

LD (PENPOS),A

PENPOS DN

LD B,02H

NO, TIME OUT

CALL TIMER

EXIT

LD HL,(RETADDR)

GET RETURN ADDRESS

JP (HL)

RETURN

.END

Listing 4: The machine-language procedure "plotinit". This procedure initializes theserial output port at the beginning of a drawing session. It is dependent on the specifichardware used in the author's system.

.PROC PLOTINIT

LD A,05H

OUT (78H),A

LD A,01H

OUT (7 8H),A

RET

.END

;RETURN

238 October 1981 © BYTE Publications Ire

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BYTE October 1981

241

Text continued from page 222:point. The characters "[" and "]",when passed in a string, causesubscripts and superscripts to beplotted. Any characters enclosed inbrackets (eg: this is a [superscript])will be plotted spaced up one half theheight of the characters, and anycharacter enclosed in "unbrackets"(eg: this is a ]subscript[) will be plot-ted spaced a similar distance belowthe current line.

The plotting of arrows is anotherspecial case. If an arrow is to beplotted, it will be plotted with aheight as specified in the parameterpassed to "plotstring", but the head ofthe arrow will always be of the samesize. Thus, arrows can be plottedrepresenting, for example, thestrength of the current in a given cir-cuit, with the length of the arrow be-ing proportional to the current.

If you want to generate any specialcharacters of your own, it is a simplematter to decide on the shape of thecharacter (which, by the way, mustreside within a "box" 7 moves high by4 moves wide) and generate it bycoding the appropriate moves usingthe two vector pads I described

above. The characters I have alreadyencoded are shown in figure 2.

The procedure "plotwhere" is usedto locate the pen on the plotting bed.It is passed two real variables andreturns them loaded with the currentx and y locations of the plotting pen.This procedure is useful when youwant to add a comment or identifyingremark to a point or line being drawnon the plot. Simply call "plotwhere",displace the pen an appropriatedistance from the current pen posi-tion, plot the comment, and returnthe pen to its initial position.

Graph-Plotting Procedures

The procedure "plotarray" is rathercomplicated. It is used to plot an ar-ray of up to 256 points. Of course,plotting more than that number ofpoints can be done by calling it morethan once. The procedure is passedthe number of points to be plotted,the frequency of any identifying sym-bol to be plotted, the identifier of thesymbol to be used, the beginningpoint of the plot, the range of the xand y variables, the height of thesymbols, the area the plot is to oc-

cupy, and, last but not least, the twoarrays (of type "coord") that containthe x and y coordinates of the desiredplot.

This may seem like a large numberof parameters to be passing to theprocedure, but it allows for a greatdeal of flexibility in plotting arraysand is, in fact, easier to use in practicethan it is to describe. What "plotar-ray" does is to simply scale the loca-tion of the points passed to it and fitthem into the space indicated. It thenmoves the pen to the series of (x,y)points given by the two arrays of"coord"s, with the pen either up ordown, depending upon the sign of thefrequency of symbols passed. If thefrequency of symbols is passed as 0,no identifying symbols will beplotted; if it is 1, every point will beidentified; if it is 2, every other point,and so on. If frequency is negative,only the points will be plotted, withno interconnecting lines. As im-plemented, the points can be iden-tified by five different symbols:triangle, X, square, +, or verticalline. These are selected by passing thesymbol as 1, 2, 3, 4, or 5, respective-

THESE ARE THE CHRRRCTERS RURILRBLE

flBCDEEGHIJKLHH0PQRSTUUklXYZ0123456789

=><$V%? ",()%+-

THIS IS RH ARROW

THIS IS fl SUPERSCRIPTTHIS IS fl SUBSCRIPT

Figure 2: An example showing the letters, special characters, and plotting options available through the "plotstring" procedure.

242 October 1981 © BYTE Publications Inc

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BYTE October 1981 245

Iy. The size of the plotted symbol ispassed in the height variable.

The procedure "plotsymbol" isused to plot any of the five identify-ing symbols. These symbols are usedin procedure "plotarray" if someidentifying point marker is desired.The procedure is passed integers thatidentify the symbol to be plotted andthe height of the desired symbol. Thesymbol will be plotted centered at thecurrent pen position. This procedurecan be used both to identify points ona plot and in a description of themeaning of those points (see the ex-

ample plot in figure 3 and listing 2).The procedure "plotaxis" is used toplot an axis with its identification andvalues. It is most often used in con-junction with "plotarray" to plot ex-perimental data but, of course, can beused in any other way for special pur-poses. The procedure is passed thelocation of the origin of the axis, itslength in inches, the angle of the axiswith respect to the long axis of theplotting paper, the minimum andmaximum values represented on theaxis, how often tic marks should oc-cur on the axis, and the name of the

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axis. If length is passed as negative,no labeling of tic marks or axis willoccur. If the tic-mark value is passedas negative, the labeling of both axisand tic marks is done on the counter-clockwise side of the axis. This laststep is included so labels on axis canbe put on the "outside" of the plotarea in the case of two-axis plots (seethe example plot).

I should mention here that there isa limitation on the size of tic-marklabels. A floating-point error will begenerated if you try to make any labellarger than ±327.67. This is becauseinteger arithmetic is used to translatefrom the floating-point number to thestring variable plotted as the tic-marklabel. An easy way around this is todo it as I did in the sample plot anduse a factor-of-ten multiplier in theaxis label to compensate (see figure3).

The plot in figure 3 with its accom-panying listing demonstrates how theplotter subroutines can be used togenerate a plot with a minimum ofprogramming effort.

Implementation Details

These plotter procedures weredeveloped using an SD SystemsSBC-100 microprocessor board and aVDB-8024 video board. If they are tobe used on systems other than the onedescribed, a few modifications willhave to be made. The constants"screenwidth" and "screenheight"defined in the "const" section of theimplementation section in listing 1should be changed to reflect the sizeof your own screen, and the charactervariable "clear", defined in procedure"initplot", should be changed toreflect the character that causes yourscreen to be cleared. Thus, it will onlybe necessary for you to write yourown "plotstep" and "plotinit"subroutines for the "plotter" unit so itis functional on your computer.

I'm not familiar with other plotters,but I suspect that these proceduresmight be usable on other machinesafter the appropriate modifications toprocedures "plotstep" and "plotline"have been made.

If you would like a copy of thesource for these plotter programs, I'dbe happy to supply it. Just send me ablank 8-inch floppy disk and $10, andI will return it to you with the sourcecode for all of the programs describedin this article. ■

246 October 1981 © BYTE Publications Inc

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TO PLACE YOUR ORDER CALL:

TELEPHONE TELEX

(714) 744-7314 697120

or write to:

PALOMAft

Computer Products

910-105 W. San Marcos Blvd., San Marcos, CA 92069

TERMS OF SALE: Cash, check, money order, bank wire transfer. Hcredit card or purchase orders from qualified firms and Hinstitutions. Please include telephone number with order andexpiration date on credit card orders California residents add 6*sales tax Advertised pnces are for prepaid orders FOB shippingpoint Add 3% for shipping in (IS Pncing and availability subject tochange without notice

■

i

Circle 292 on inquiry card.

How could we ever top the "Big 16" package? Here's how...

SUPERSIXTEEN!

SuperSixteen combines our most acclaimed system components in a specially-pricedpackage configuration. Imagine a computer that executes the present library of 8 bitsoftware as well as the 16 bit software of the future.. .handles the most demandingcommercial, industrial, and scientific applications... con forms to all IEEE 696/S-100standards to allow for compatibility and easy upgrading...runs the new generation ofhigh-performance/enhanced software (such as Sorcim's "SuperCalc" financialplanning package)...is backed by a full 1 year—not 90 day—limited warranty...and,unlike many of the ' 'personal'' computers being adapted for commercial applications,won't be here today and outgrown tomorrow.

That's exactly what SuperSixteen delivers, and at a price that's intended to be asirresistible as the benefits. Each SuperSixteen package includes:

• Dual Processor Board. Executes both 8 and 16 bit code to handle present and futureneeds. High speed (5 MHz) 8085 and 8088 processors complete jobs faster.

• Disk 1 DMA Floppy Disk Controller. Features lightning fast operation, thanks toproperly implemented DMA (with arbitration). Handles up to four 8" or 5.25" floppydisk drives, single or double-sided, single or double density (soft sectored).

• System Support 1. All the most popular "extras" on one board: battery operatedclock/calendar; RS-232 serial port; battery backup RAM, math processor, and ROMoptions; triple interval timers; dual interrupt controllers; power fail interrupt; and more.

• Interfacer 1. Two RS-232 serial ports, with full handshaking and independentlyselectable Baud rates up to 19.2 KBaud, connect to the serial peripherals (printer,terminal) of you choice.

• 128K of Static RAM. The best components deserve the best memory, which is why128K of our famous high speed/low power RAM comes standard with every SuperSixteenpackage.

• CP/M*-2.2. The most popular 8 bit operating system, ready to load and go.

• CP/M*-86. Ready to load and go for 16 bit operation.

• Cable and Documentation. Each package includes three interfacer cables, onedisk cable, complete documentation for all hardware, and manuals for both CP/M*operating systems.

816

If purchased separately, these quality components would cost $4,344. ButSuperSixteen's low package is an amazing $3,495 - that's like getting 48K ofmemory for free! (For boards qualified under the Certified System Componenthigh-reliability program - with extended 2 year warranty, 200 hour burn-in, and 6MHz processors - add $600 to the package price.)

•CP/M is a trademark of Digital Research. Prices shown do noi include dealer installation and suppon services.

You can wait for the other manufacturers to catch up...or you can enjoythe competitive edge offered by CompuPro products right now.SuperSixteen is available at finer computer stores world-wide; call415-562-0636 for the authorized CompuPro sales center nearestyou.

CompuPro"

(PEW*

Electronics^

OAKLAND AIRPORT, CA 94614 (415) 5620636

Circle 77 on inquiry card.

PROVEN Computing SOLUTIONS

We give you more of what you buy a computer for: to gain a competitiveedge in your industrial, commercial, or scientific application. While othercomputers try to make the best of slow memory, slow processors, and me-tooengineering, CompuPro is delivering solutions for today's commercial computing.. .proven solutions that create expandable, modular, fast, exceptionally reliable,and truly professional level machines that conform fully to the IEEE 696/S-100standards. We back all products with a minimum 1 year limited warranty.

When you depend on your computer, choose a computer on which you can depend:

S-100 from CompuPro.

1 DISK 1 DMA DISK CONTROLLER. Disk controllers don't have to beyour system's bottleneck: Disk 1 is lightning fast, thanks to properlyimplemented DMA (with arbitration) and data transfer that's independent ofCPU speed. Handles up to four 8" or 5.25" floppy disk drives, single ordouble-sided, single or double density (soft sectored). With BIOS forCP/M-80*. Manual available for $25. A/T $495, CSC $595. Comingsoon: Disk 2, the fast DMA Hard Disk Controller.

2 CP/M-86. Available only with Disk 1 purchase. Supplied on diskette withfull documentation; ready for load and go operation. $300.

3 OASIS* OPERATING SYSTEM. Single user ($500)and multi-user ($850)available for use with CPU Z. Supplied on diskette with full documentation.Coming soon: OASIS 16 for use with 16 bit systems.

4 COMPLETE DUAL DISK DRIVE SYSTEM. With one Disk 1 board,desktop dual drive enclosure with Shugart SA-800 series drives, and powersupply cable. Also includes CP/M-80. Introductory special: $2195.

5 SYSTEM SUPPORT 1. Includes battery operated clock/calendar;sockets for battery backup RAM, optional 9511 or 9512 math processor, and2716 ROM; RS-232 serial port; triple interval timers; dual interruptcontrollers; power fail interrupt; and more. Comprehensive owner's manualincludes numerous software examples. $295 Unkit, $395 A/T, $495 CSC (addS195 to the above prices for the optional math processor).

6 8 BIT CPU Z. A Z80*-based CPU board that includes all standardfeatures plus many convenience options. Meets all IEEE 696/S-100specifications, including timing. $225 Unkit, $295 A/T (both operate at 4MHz), $395 CSC (with 6 MHz CPU).

7 16/8 BIT CPU 8085/88. Now there's an easy way to gain 16 bit capabilitywithout sacrificing your library of 8 bit software: CPU 8085/88 combines an8088 CPU to handle 16 bit software and an 8085 CPU for 8 bit software. $295Unkit, $425 A/T (both operate at 5 MHz); $525 CSC (with 6 MHz 8085 and8088).

8 8088/8086 MONITOR-DEBUGGER SOFTWARE. Ideal for use withCPU 8085/88. Supplied on single sided, single density, soft sectored 8" disk.CP/M-80 compatible (not required if you have CPM/86). Great developmenttoo!; mnemonics used in debug conform as closely as possible to currentCP/M DDT mnemonics. $35.

9 8 BIT CPU 8085. Same as CPU 8085/88, but without 8088. May be easilyupgraded to 16 bit operation. $235 Unkit, $325 A/T, $425 CSC.

10 INTERFACER 1. Two RS-232 serial ports, with full handshaking andindependently selectable Baud rates, connect your computer to serialperipherals. $199 Unkit, $249 A/T, $324 CSC.

11 INTERFACER 2. Adds three full duplex parallel ports, and one serialport with all the features of an Interfacer 1 serial port, to your computer. $199Unkit, $249 A/T, $324 CSC.

12 INTERFACER 3-5. Includes five RS-232 serial ports (2 synchronous/asynchronous. 3 asynchronous) with full handshaking. Includes softwareprogrammable Baud rates and many other convenience features. $599 A/T,$699 CSC.

13 INTERFACER 3-8. Same as above, but with eight full RS-232 serial ports(2 synchronous/asynchronous, 6 asynchronous). Ideal for multi-user/multi-terminal systems. $699 A/T, $849 CSC.

14 SPECTRUM COLOR GRAPHICS BOARD. With 8K of IEEE-compa-tible static RAM, full duplex bidirectional I/O port for keyboard or joystickinterface, and 6847-based graphics generator that can display all 64 ASCIIcharacters. 10 modes of operation, from alphanumerics/semi-graphics in 8colors to dense 256 X 192 full graphics. $299 Unkit, $399 A/T, $449 CSC.

15 6 SLOT HIGH SPEED MOTHERBOARD. With all edge connectors,Faraday shielding, extensive bypassing, and split active termination. $89Unkit, $129 A/T.

16 12 SLOT HIGH SPEED MOTHERBOARD. Same as above, but with 12slots. $129 Unkit, $169 A/T.

17 20 SLOT HIGH SPEED MOTHERBOARD. Same as above, but with 20slots. $174 Unkit, $214 A/T.

18 MEMORY MANAGER. Extends the addressing of older S-100 machinesbeyond 64 KBytes to allow for greatly expanded memory capacity. $59 Unkit,$85 A/T, $100 CSC.

19 ACTIVE TERMINATOR. Promotes reliable and accurate data transferin older machines by properly terminating bus lines, thereby minimizingringing, crosstalk, overshoot, noise, and other gremlins associated withunlerminated lines. $34.50 Unkit, $59.50 A/T.

20 2708 EPROM BOARD. This board is the way to store often used routinesor pieces of software. $85 Unkit, $135 A/T, $195 CSC (2708s not included).

21 DOCUMENTATION. User manuals are available for all products.Interfacer 3, $10; Disk Controller, $25; System Support 1, $20; most others,$5. Also available: "CompuPro Product User Manuals: 1975 - 1980". This250+ page book includes data on all older Godbout/CompuPro products, aswell as many newer products such as the Spectrum Color Graphics board,Interfaces 1 and 2, CPU 8085/88, motherboards, CPU Z, and more. Whetheryou want to evaluate the innovative engineering behind CompuPro products,or study the nuts and bolts of high speed computer operation, this is the bookfor you. $20 plus shipping.

22 RAM 16-64. Configurable as 64K X 8 for 8 bit systems or 32K X 16 for16 bit systems. Static, IEEE-696/S-100 compatible, extended addressing, 10MHz operation. $1195 A/T, $1295 CSC.

23 RAM 17-64. The lowest power 0/t Amp typical) 64K X 8 static board inthe business. IEEE-696/S-100 compatible, 4 optional 2K windows, no waitstates with 6 MHz Z80. $1095 A/T, $1195 CSC, $875 Unkit.

24 RAM 20-32. For lower density applications. Static, IEEE-696/S-100compatible, extended addressing or bank select, up to 10 MHz operation.$559 A/T, $659 CSC, $449 Unkit. 8K and 16K versions also available.

Most CompuPrn products arc available in Unkit form, Assembled/Tested (both with I year warranty).or qualified under the high-reliability Certified System Component (CSC) program (200 hour bum-in.2 vear extended warranty, more). Note: Unkils are not intended for novices, as de-bugging may herequired due to problems such as IC infant mortality. Factory service is available for Unbits at a flatservice charge.

•LEGAL CORNER: Z80 is a registered trademark of Zilog; CP/M is a registered trademark ofDigital Research; OASIS is a trademark of Phase I.

How to Order: Call 415-562-0636 for the name of theauthorized CompuPro sales center nearest you, or forplacing factory direct VISA ©/Mastercard® orders.Prices shown do not include tax, shipping charges,or dealer installation/support services.

Circle 77 on inquiry card.

CompuPro™

(pGJBIilfi'

Electronics^

OAKLAND AIRPORT, CA 94614 (415) 5620636

BYTE October 1981

249

Evaluate YourHome's Energy Efficiency

Conserve Energy with Your Computer

As we are all too well aware, thecost of heating a home has sky-rocketed in recent years. Many home-owners, searching for ways to im-prove the energy efficiency of theirhomes, add insulation to the walls orroof, install storm windows, or caulkand weather-strip around windowsand doors. Money is spent on one ormore of these energy-conservationplans only because homeowners ex-pect a reasonable return on their in-vestment in the form of lower heatingbills.

Many homeowners, however, willspend a great deal of money on insu-lation for the walls or ceiling, for ex-ample, without having any idea howmuch their heating costs will actuallybe reduced. At some thickness, add-ing more insulation is no longer cost-effective. The "proper" thickness isvery difficult to determine. Also, if ahouse has heat losses through single-pane windows or air leaks from poorweather stripping, adding insulationto the walls will not do much to re-duce the overall heat loss. In short,homeowners usually suffer from alack of information on the thermalproperties and energy efficiency oftheir homes.

Kimball Beasley

Wiss, Janney, Elstner and Associates Inc

330 Pfingsten Rd

Northbrook IL 60062

There are two basic ways to findthe energy savings and return onmoney invested with a home heatingenergy-conservation plan:

• Choose a plan, have it done, andwait for the heating bills to arrive todetermine actual energy savings.

• Choose a plan and analyze the en-ergy-efficiency improvement to findthe energy savings before spendingmoney.

To analyze the energy-efficiencyimprovement, such factors as cli-mate, existing insulation, and build-ing dimensions must be determined,as well the heat-transfer properties ofall exposed surfaces. Inasmuch aseach house has unique and complexheat-loss characteristics, any analysiswill be somewhat involved.

Listing 1 (see page 258) is a com-puter program to evaluate the phy-sical properties of a house. The pro-gram analyzes and displays heat lossthrough each exposed building ele-ment (walls, windows, etc) and pro-vides the computed heat lossesassociated with a selected heatingenergy-conservation plan. The pro-gram will run on the Radio ShackTRS-80 Model I and, with few

changes, it can be adapted to mostsmall computers. With this program,the most efficient heating energy-conservation plan can be selected,and the approximate return on invest-ment can be derived from the com-puted heating-cost savings. Fun-damental to this program is the sup-position that any heating energy-conservation plan is properly done(i.e., insulation evenly distributedwith proper vapor barriers, or goodconstruction practices for installingstorm windows or adding weatherstripping).

Figure 1 (see page 252) includes aworksheet and an exploded drawingof a typical house. The worksheetand drawing are an aid to help inorganizing the required data beforeworking with the computer. The firstpart of the worksheet asks for the sur-face area of all exposed buildingelements through which heat canescape. The second part asks for thethickness and R-factor of insulationalready present in the walls, roof, orceiling. (The R-factor is a measure ofhow well a material will insulate. Thehigher the R-factor, the greater the ef-fective insulation.) If the attic isheated, the thickness of insulation in

250 October 1981 © BYTE Publications Inc

How to succeedin businesswithout realtytrying.

Gar peanuts.

STC is proud to formally an-nounce four field-proven busi-ness packages for APPLE users.And an irresistible offer.

All of these programs arestraightforward, easy to use,virtually foolproof, and veryattractively priced. The price'squoted include both the pro-grams and easy-to-followinstruction manual.

Accounts Payable

Uses ISAM structured routinesand all posting is done in secondsas opposed to hours with otherprograms. Various reports aregenerated, including cash re-quirement journal, check register,open invoice report, Y-T-D pay-ment journal, and aging functionto tell how many days left fora discount or an invoice. Youalso get a complete audit trail onall transactions, a current andY-T-D analysis of all your ac-counts and vendors, and a checkprinted on available forms.Only $200.

Payroll

Maintains an entire payroll for upto 125 employees. It providesnumerous payroll utilities forquick and easy payroll and checkgeneration. It has built-in Federaland State tax tables and pro-vides some remarkable reportingcapabilities. Only $240.

Professional Time and Billing

Maintains time and billing datafor up to 300 clients. 120 rates[employees] can be on file at anytime. Rates may appear as time/expenses/fixed fees. Printsstatements on available forms.Generates a variety of transac-tions and activity reports, andmuch more. Only $325.

Apartment Management

Maintain financial and managerialdata for up to 6 separate apart-ment complexes. Each complexcan contain a maximum of 120units and 8 different types ofunits. Generates an operatingstatement which contains YTDrental income, security deposits,pet deposits, pool deposits, misc.deposits, damageamounts, allowancesexpenses and a completebreakdown of apt. units bytype. Again, some greatreports Only $325.

Early Bird Offer

If you purchase any one of theseprograms from your STC dealerwithin the next 30 days, we'lllet you have our new and quitefantastic Coloring Board pack-age for only $30. This program,normally costing $60, compareswith some hardware capabilitiescosting $800 and more. It allowsyou to quickly create, store anddisplay all types of graphics andtext labeling. For example, a bar-chart like the one shown abovefor display at sales meetings. Inshort, it has unlimited usefulapplications for business.

Act now. Contact your localSTC dealer for details on thisextremely unusual offer. Andbe sure to check out the restof our great line of softwarepackages as well.

Dealer inquiries invited.

[Apple is a trademark of Apple ComputerCompany]

SOFTWARE TECHNOLOGY (or COMPUTERS

P.O. Box 428. Belmont, MA 02178 (617|923-4334

Circle 333 on inquiry card.

BYTE October 1981 251

Worksheet

Exposed Surface Areas

Calculation

Sample

House

Your H

Duse

Calculation

Area in

Square

Feet

Calculation

Area in

Square

Feet

Total Window Area

(N = Number of Windows)

With Double PanesWith Single Panes

NxhxwNxhxw

lix3xH =

lit(*<*

Total

I4S

Total

Total Wall Area

(2xWxH) +

(2xLxH)-

Total Window Area

(zxloxid)+(z*So*Zo)-(99 =

3 0O2.

Total Roof/Ceiling AreaRoof—If Attic Is HeatedCeiling—If Attic Is Unheated

(2 x L x S) + (W x A)LxW

So x 30 =

1500

Total Door Area

(N = Total Number of Doors)

Nxhxw

Z*7x3 =

42L

Existing Insulation

ThicknessIn Inches

R-Factor(table 1)

ThicknessIn Inches

R-Factor(Table 1)

Insulation in Walls

2.

1

Insulation in Roof/Ceiling

RoofCeiling*

3

z

II

9

Total

s

to

*lf attic is heated, disregard ceiling insulation.

Sample

House

structure:

typical window:

H = 20 feet

h = 3 feet

W = 30 feet

w = 4 feet

L= 50 feet

A = 6 feet

picture window:

S = 16

h = 5'/2 feet

w= 12 feet

S can be calculated from A and W:

typical door:h = 7 feet

S = VW2/4 + A2

w = 3 feet

• ceiling insulation thickness = 2 inches

• roof insulation thickness = 3 inches

• wall insulation thickness = 2 inches

Figure 1: Worksheet and exploded view of house. Data for the sample house is entered here in figure la, and the resulting output fortwo plans is shown in figure 3. Use a photocopy of the blank worksheet (figure lb) to help organize your data before entering it intothe computer.

252 October 1981 © BYTE Publications Inc

Worksheet

Exposed Surface Areas

Calculation

Sample

House

Your H

ouse

Calculation

Area in

Square

Feet

Calculation

Area in

Square

Feet

Total Window Area(N = Number of Windows)

With Double PanesWith Single Panes

N xh xwNxhxw

Total

Total

Total Wall Area

(2xWxH) +

(2xLxH)-

Total Window Area

Total Roof/Ceiling AreaRoof—If Attic Is HeatedCeiling—If Attic Is Unheated

(2 x L x S) + (W x A)LxW

Total Door Area

(N = Total Number of Doors)

Nxhxw

Existing Insulation

ThicknessIn Inches

R-Factor

(table 1)

ThicknessIn Inches

R-Factor(Table 1)

Insulation in Walls

Insulation in Roof/Ceiling

RoofCeiling*

Total

*lf attic is heated, disregard ceiling insulation.Figure lb: Blank worksheet to help you organize data before calculating your home's energy efficiency.

the roof and the roof's surface areaare entered in the worksheet (ceilingarea and insulation do not apply sincethe ceiling is not exposed to the cold).If the attic is unheated, the ceiling sur-face area and the combined thicknessof insulation in the roof and ceilingare entered in the worksheet (both theroof and ceiling insulation help toreduce the heat flow to the outside).The insulation R-factor is found bychecking the thickness and type of in-sulation in table 1. (See page 254.) Forhouses with odd shapes, heated an-nexes, or unheated garages inside thehouse, the surface area of each wall,window, and so forth exposed to thecold should be added to find the in-dividual total wall, roof, window,and door areas.

Try an Example

The sample house shown in figure 1is located in Chicago, Illinois, whichis situated in heating region number 4on the map in figure 2. (See page254.) When the physical characteris-tics of this house are entered as shownin the program operation section, theheat-loss profile in figure 3a (see page256) is displayed. This profile showsthat most of the heat is lost throughthe walls. Because the existing roofand ceiling of the sample house arecomparatively well insulated, and thesample house has storm windows, Iwill plan to add 2 inches of looserockwool (R-factor 9 in table 1) to allthe walls.

Figure 3b is the computed heat-lossprofile with the added insulation in

the walls. It shows that substantiallyless heat is lost through the walls withthis plan. The overall heat-loss reduc-tion is 21%, and, since the annualheating cost for the sample house is$900, the yearly saving with this planis $191. It must be considered, how-ever, that adding insulation to thewalls can be very expensive. If pump-ing loose fill into all walls costs$2000, the return on investment isabout 9 % for the first year for this ex-ample (approximately a 10-yearbreakeven point with constantheating fuel costs). The programoperation is shown in figure 4. (Seepage 260.)

In the sample house, an inspectionof the caulking and weather stripping

October 1981 © BYTE Publications Inc 253

Circle 96 on inquiry card.

Z8000

MICRO PRICE for MINI POWER

MICRO-MINI" matches Series I by IBM

DELIVERING CURRENT ORDERS

You cannot buy a more powerful micro:

• Power: 1 to 32 independent users

• Memory: directly addresses to 16 Meg!

• Mapping: efficient memory management

• Disk: 2M to more than 250M

• Speed: throughput 10 times Z80

• Files: simultaneous access

• Communication: inter-user via terminals

• Security: all files password protected

• Options: expandable in the field

• Bus: Intel Multibus'" compatible

• Languages: Pascal, BASIC, COBOL, FORTRAN

System 3

$7053

computer system

This 16-bit Multibusincludes:

• Z8001 CPU and 256K RAM

• 8 serial I/O ports

• 15-slot backplane

• Dual floppy disk drives

• Multiuser Operating SystemField upgrade to 16MB RAM,

268MB of hard disk, 32 users.Pascal, BASIC, C, COBOL andFORTRAN languages.

Call for further system specifications.

AMPEX Dialogue 80™

Dialogue 80'" fully-featured video terminal:

• Full ASCII with numeric and edit keypads

• Elegant case with detachable keyboard

• Display 24 lines with 25th status line

• 20 user programmable function keys

• 2 pages display memory (4 optional)

• 11 graphics and 21 control codes

• 10 modes including block, protect, program

• Transparent mode displays control codes

Dialogue 80" $1045

Dialogue 80™ with phone coupler 1194

Applications: word processing, dataentry, interac-tive programming, data base inquiry/response/update, transaction processing, whether on-siteor remote. For our system or for yours, this inter-active terminal is the perfect match.

Prices: Prepaid or Purchase Order Net 10.Prices subject to change without notice.Warranty: 120 day minimum on all systems.Interfacing cables free with all systems.10% down fixes price, guarantees priority.MasterCard and VISA cards accepted.

(312) 684-3183

W™ COMPUTEX

^^. \ MICROCOMPUTER SYSTEMS \

\ \ 5710 Drexel, Chicago, IL 60637

around windows and doors revealsnoticeable drafts and dried-out caulkmaterial. The caulking and weatherstripping improvement plan is evalu-ated next. The results (figure 3c) showthat the total heat-loss reduction isabout 12% (or $112 annually) withthe new caulking and weather strip-ping plan. In the example, this plancosts about $200, and the return on

investment for the first year is 60%(about a two-year breakeven point).It is apparent that the caulking andweather stripping plan offers a betterreturn on investment. Assuming thatheating fuel costs will increase, how-ever, our wall-insulation plan andother costly improvement plansbecome more attractive each year.Also, air-conditioned homes will ben-

Figure 2: Six heating zones in the continental United States. These play an importantpart in figuring your heat loss. For other areas, consult your local government. (Source:United States Department of Commerce, National Bureau of Standards.)

Batts or Blankets

Loose Fill

R-Factor

Glass

Fiber

RockWool

Glass

Fiber

RockWool

CelluloseFiber

4

Wall with no insulation

6

Roof/ceiling with no insulat

on

9

2

11/2-2

3

2-2

1%-2

11

3%-4

3

5

4

3

13

4

41/2

6

4%

3%

19

6-6 %

51/2

8-9

6-7

5

22

61/2

6

10

7-8

6

26

8

8%

12

9

7-7%

30

9%-10%

9

13-14

10-11

8

33

11

10

15

11-12

9

38

12-13

10 %

17-18

13-14

10-11

44

14

11%

19-21

14-16

11-13

Table 1: R-factors for various types of insulation materials. Insulation thickness ismeasured in inches.

254 October 1981 © BYTE Publications Inc

THE ORIGINAL MAGAZINE FOROWNERS OF THE TRS-80™* MICROCOMPUTER

SOFTWARE

FOR TRS-80'"

OWNERS

H

CQIYIPLITHQMICS

* TRS-80™ IS A TRADEMARK OF TANDY CORP.

| MONTHLY

|| NEWSMAGAZINE™ FOR TRS-80'"C. OWNERS

MONTHLY NEWSMAGAZINE

Practical Support For Model I, II & HI

PRACTICAL APPLICATIONSBUSINESS

GAMBLING • GAMESEDUCATIONPERSONAL FINANCEBEGINNERS CORNERNEW PRODUCTSSOFTWARE EXCHANGEMARKET PLACEQUESTIONS AND ANSWERSPROGRAM PRINTOUTS AND MORE

NOW IN OUR 4th YEAR

PROGRAMS AND ARTICLES PUBLISHED IN RECENT ISSUESINCLUDE THE FOLLOWING:

• FINCALC ■ A COMPLETE FINANCIAL APPLICATIONS 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

f*S*i

%»»»»*»»»^»V»»%»»»»»»%-»»»»»»»1

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- «>ftC^ To Calculate Markup, Margin, Annuities

S o^ « And Effective Rates, Sinking Funds, Mortgage Calculations, Future Value,

Difference Between Two Numbers,

A Complete Financial Analysis Package UsedCompound Interest, Nominal

cl^fiN^ Savings and Insurance, Percentage** Amortization Schedule and More . .

SEND FOR OUR NEW 64 PAGE SOFTWARE CATALOG (INCLUDING LISTINGS OF HUNDREDS OF TRS-80'" PROGRAMS AVAILABLE ONCASSETTE 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 (or modified Mod-II Version).

iCQMPLJTRQUICS

IVlttTve^lAlCAl. -

50 N. PASCACK ROADSPRING VALLEY, NEW YORK 10977

ONE YEAR SUBSCRIPTION $24

TWO YEAR SUBSCRIPTION $48

SAMPLE OF LATEST ISSUE $ 4

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(#1 - July 1978 • #12 - June 1979 • #24 - July 1980 'NEW SUBSCRIPTION RENEWAL

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Circle 161 on inquiry card. BYTE 0clober 19al 255

WHAT'S

BETTER

THAN AN

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And Will Turn

MICROSOFT'S

BASIC

COBOL

FORTRAN

DIGITAL'S

PL/1-80

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PASCAL/MT+

S-BASIC

CROMEMC016K BASIC

into first class applicationlanguages?

MICRO B+

The first and most completeimplementation of B-TREEindex structures for micro-computers. B-TREES eliminateindex file reorganization.

Search

An index of over

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Values In Less

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On A Floppy Disk Systemfor only

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System Houses:MICRO B+'"

Available In Language C

Fair Com

2606 Johnson DrivDColumbia. MO 65201(314)445-3304

«H980 Fair Com

Shipping $4 USA / $8 ForeignWe accept VISA and MASTERCARD

Pl/i-80 is a trademark of Digital ResearchCSASC is a trademark of Compiler Systems. Inc.S-BASIC Is a trademark of Topaz ProgrammingPASCAL/MT- Is a trademark of MT Micro Systems

(3a) Sample House Energy-Efficiency Analysis HEAT LOSS PROFILE

Loss through WallsLoss through Roof/CeilingLoss through WindowsAir Infiltration Loss

Total Heat Loss

10916

BTU/HR

2608

BTU/HR

5280

BTU/HR

4328

BTU/HR

23133

BTU/HR

(3b)

Sample House Energy-Efficiency Improvement With Wall-Insulation Addition Plan HEAT LOSS PROFILE WITH PLAN

Loss through Walls 6004 BTU/HR

Loss through Roof/Ceiling 2608 BTU/HR

Loss through Windows 5280 BTU/HR

Air Infiltration Loss 4328 BTU/HR

18221 BTU/HR

21%$191

Total Heat Loss

Heat Loss Reduction

Annual Savings in Heating Cost =

(3c)

Sample House Energy-Efficiency Improvement With Caulking/Weather Stripping

Plan HEAT LOSS PROFILE WITH PLAN

Loss through Walls 10916 BTU/HR

Loss through Roof/Ceiling 2608 BTU/HR

Loss through Windows 5280 BTU/HR

Air Infiltration Loss 1442 BTU/HR

Total Heat Loss

Heat Loss Reduction

Annual Savings in Heating Cost =

20247

BTU/HR

12%

$112

Figure 3: Energy-efficiency analysis for the sample house as provided by the program inlisting 1. The heat-loss profile in based on existing conditions and represents the samplehouse's current total heat loss. Nearly 47% of the total heat loss is through the walls.Figure 3b shows that by adding 2 inches of loose rockwool, the total heat loss can bereduced by 21%, for an estimated annual savings of $191. On the other hand, by caulk-ing and weather-stripping the doors and windows, a reduction of 12% of the total heatloss can be achieved at a cost of about $112. Note that these figures are based on a con-stant cost for heating. As the cost for heating increases, more expensive methods of im-proving heat loss become cost-effective.

efit from most heating energy-im-provement plans. If a house is air-conditioned, the plan with a margin-ally poor return on investment forheating efficiency is probably aworthwhile investment, when thetotal energy-efficiency improvementis considered.

Other Factors to Consider

The heat-loss properties of each

house can be very complex and sub-ject to many unknown factors. Varia-tions in construction techniques andmaterials make it impossible to exact-ly determine heat-transfer coefficientsfor each building element. The heatlost from air infiltration depends onsuch indeterminate factors as howloose each door and window fits, out-side wind speed, and what amount oftime outside doors are left open whenentering or exiting. Effectiveness of

256 October 1981 © BYTE Publications Inc

CQMPIJTRQNXCS

NC.

EVERYTHING FOR YOUR TRS-80* • ATARI* • APPLE* • PET* •

•TRS-&0 is a trademark of (he Radio Shack 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

100 Ready-To-RunBusiness Programs

^■1 „ssed wilhin 24-Hours

* 30-Day ™°nev °Software

(ON CASSETTE OR DISKETTE) Includes 110 Page Users Manual 5 Cassettes (Or Diskettes)

Inventory Control Payroll Bookkeeping System Stock Calculations

Checkbook Maintenance.....Accounts Receivable....Accounts Payable

BUSINESS 100 PROGRAM LIST

1 RULE7B

2 ANNU1

3 DATE

4 DAYYEAR

5 LEASEINT

6 BREAKEVN

7 DEPRSL

8 DEPRSY

9 DEPRDB

10 DEPRDDB

11 TAXDEP

12 CHECK2

13 CHECKBK1

14 MORTGAGE/A

15 MULTMON

16 SALVAGE

17 RRVARIN

18 RRCONST

19 EFFECT

20 FVAL

21 FVAL

22 LOANPAY

23 REGWTTH

24 SIMPDISK

25 DATEVAL

26 ANNUDEF

27 MARKUP

28 SINKFUND

29 BONDVAL

30 DEPLETE

31 BLACKSH

32 STOCVAL1

33 WARVAL

34 BONDVAL2

35 EPSEST

36 BETAALPH

37 SHARPE1

38 OPTWRrTE

39 RTVAL

40 EXPVAL

41 BAYES

42 VALPRINF

43 VALADINF

44 UTIUTY

45 SIMPLEX

46 TRANS

47 EOQ

48 QCIEUE1

49 CVP

50 CONDPROF

51 OPTLOSS

52 FQCJOQ

NAME

53 FQEOWSH

54 FQEOQPB

55 QUEUECB

56 NCFANAL

57 PROF1ND

58 CAP1

Interest Apportionment by Rule of the 78's

Annuity computation program

Time between dates

Day of year a particular date falls on

Interest rate on lease

Breakeven analysis

Straightline depreciation

Sum of the digits depreciation

Declining balance depreciation

Double declining balance depreciation

Cash flow vs. depreciation tables

Prints NEBS checks along with dairy register

Checkbook maintenance program

Mortgage amortization table

Computes time needed for money to double, triple.

Determines salvage value of an investment

Rate of return on investment with variable inflows

Rate of return on investment with constant inflows

Effective interest rate of a loan

Future value of an investment (compound interest)

Present value of a future amount

Amount of payment on a loan

Equal withdrawals from investment to leave 0 over

Simple discount analysis

Equivalent & nonequivalent dated values for oblig.

Present value of defened annuities

% Markup analysis for items

Sinking fund amortization program

Value of a bond

Depletion analysis

Black Scholes options analysis

Expected return on stock via discounts dividends

Value of a warrant

Value of a bond

Estimate of future earnings per share for company

Computes alpha and beta variables for stock

Portfolio selection model-i.e. what stocks to hold

Option writing computations

Value of a right

Expected value analysis

Bayesian decisions

Value of perfect information

Value of additional information

Derives utility function

Linear programming solution by simplex method

Transportation method for linear programming

Economic order quantity inventory model

Single server queueing (waiting line) model

Cost-volume-profit analysis

Conditional profit tables

Opportunity loss tables

Fixed quantity economic order quantity model

DESCRIPTION

As above but with shortages permitted

As above but with quantity price breaks

Cost-benefit waiting line analysis

Net cash-flow analysis for simple investment

Profitability index of a project

Cap. Asset Pr. Model analysis 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 FINRAT Financial ratios for a firm

64 NPV Net present value of project

65 PRINDLAS 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 FCIPRINF Future price estimation with inflation

71 MAILPAC Mailing list system

72 LETWRT Letter writing system-links with MAILPAC

73 SORT3 Sorts list of names

74 LABEL I Shipping label maker

75 LABEL2 Name label maker

76 BUSBUD DOME business bookkeeping system

77 T1MECLCK Computes weeks total hours from timeclock info.

78 ACCTPAY In memory accounts payable system-storage permitted

79 INVOICE Generate invoice on screen and print on printer

80 INVENT2 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 (JPSZONE Finds UPS zones from zip code

91 ENVELOPE Types envelope including return address

92 AUTOEXP Automobile expense analysis

93 INSF1LE Insurance policy file

94 PAYROLL2 In memory payroll system

95 DILANAL Dilution analysis

96 LOANAFFD Loan amount a borrower can afford

97 RENTPRCH Purchase price for rental property

98 SALELEAS Sale-leaseback analysis

99 RRCONVBD Investor's rate of return on convertible bond100 PORTVAL9 Stock market portfolio storage-valuation program

Circle 162 on inquiry card.

D CASSETTE VERSIOND DISKETTE VERSIOND TRS-80* MODEL II VERSION

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Listing 1: A TRS-80 BASIC program to perform an energy-efficiency analysis of yourhome. After asking for your home's vital statistics, the program presents an analysis ofyour present heat losses. Then, by entering options 1 through 4, you can evaluate theresults of the various energy-conservation plans on your house. Data for plans 1 and 4for the sample house described in the text are shown in figure 3.

40506070

SO90

too

1101201 30140150160170180190200210220230240250260270280290300310

3 20330340350360370380390400

4 1042043044045046047048049050^)510520530540550560570

REM-- ■ - ENERB

CLS

REM BUILD 11-46 SURFACE

INPUT "HEATING ZONE

T=N*10

rOTAL

TOTAL

TOTAL

TOTAL

"TOTAL

EF'F ICIENCY ANALYBIS-~

AREA(FROM

AND EXISTINGMAP) " ■ N

INSULATION

DOUBLE PANE WINDOW AREA (SQUARE

SINGLE-PANE WINDOW AREA (SQUAREWALL AREA (SQUARE FEET)";WAROOF/CEILING AREA (SQUARE FEET)'DOOR AREA (SQUARE FEET)";DA

INPUTINPUTINPUTINPUT

INPUT

INPUT "R-FACTOR OF EXISTING WALL.

INPUT "R-FACTOR OF EXISTING ROOF,

CLS

PR I NT " - — HEAT LOSS PROF I I....E-

PR I NT :: WL= ( 1 / ( WR+2 ) ) *WA*T

RL=<1/(RR+3))*RA*T

6L= (.. 45*GW*T) + (1. 1 *BA*T)

DL=„54*(.8*(BA+GW)+ DA)#T

PRINT "LOSS THROUGH WALL

PRINT "LOSS THROUGH ROOF/CEILINB

PRINT "AIR INFILTRATION LOSS

PRINT "LOSS THROUGH WINDOWS

TL= I NT (WL-t RL+GL+DL )

PRINT

"TOTAL HEAT LOSS

PRINT "ENERGY EFFICIENCY

FEET)FEET)

1 RA

BW

GA

INSULATION"5WR

CEILINB INSULATION'

;RR

'ADD WALL INSULATION'ADD ROOF/CEILING INBULf'.INSTALL STORM WINDOWS'CAULK AND WEATHERSTRIP

"INT (WD ; "BTU

3 "INT(RL)s"BTU."INT(DL);"BTU"IMT(GL) :; "BTU,

'HRHR

'HR'HR

"TL;"BTU/HR"IMPROVEMENT FLAN"

(ENTER 1)"

ION (ENTER 2)"

(ENTER 3)"

(ENTER 4)"

E

'0

GOTO

GL=(.45# (GA-i-GW) *T>

DL=.IS*(.B*(GA+GW)+DA)*T

PRINT

PRINT

PRINT

PRINT

PRINT

PR I NT

PRINT

INPUT

IF E<3 THEN

IF E=3 THEN

IF E==4 THEN

GOTO 400

INPUT "ADDED R-FACTOR OF NEW INSULATION";r

IF E=l THEN WL==(1/ (WR+2+R) ) *WA*T

IF E=2 THEN RL=(1/(RR+3+R))*RA*T

CLS I PRINT" HEAT LOSS PROF

PRINT

LOSS THROUGH WALL

LOSS THROUGH ROOF/CEILING

LOSS THROUGH WINDOWS

AIR INFILTRATION LOSS

N=INT(WL+RL+GL+DL)

TOTAL HEAT LOSS

E WITH PLAN

999 I:

PRINTPR I NTPRINTPR I NTPRINT:PRINTPRINT-PRINTPRINT:PRINTPRINTPRINTINPUTIF X = lIF X = 2PRINTINPUTIF Y-lPRINTND

'INT(WL)'INT(RL)'INT(GL)'INT(DL)

'BTU/HR''BTU/HR''BTU/HR"'BTU/HR"

'TN;"BTU/HR'

"HEATIIMPUT

LOSS REDUCTION "INT("TOTAL ANNUAL HEATING

((TL-TN)/C0ST"sH

TL)*100>

INI

(H*(TL-TN)/OF OTHER'F NO)"sX

"ANNUAL HEATING"DO YOU WANT TO"IMPROVEMENTS ?

THEN CLS:GOTO

THEN CLS"DO YOU WANT TO RUN THIS PROGRAM FOR ANOTHER"BUILDING ? (ENTER 1 IF YES - 2 IF NO)";Y

THEN GOTO 20 ELSE CLS"ENERGY AUDIT' PROGRAM TERMINATED"

COST SAVINBS=*CHECK THE EFFICIENCY(ENTER 1 IF YES - 2260

RUN

TL)

258 October 1981 © BYTE Publications Inc

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COmPUTER DEVICES

1930 W.COUinJ AVE.

ORAnGE, CA 9S668

(714)633-7980

PROGRAM OPERATION

Computer Display

Sample HouseData fromWorksheet

Comments

HEATING ZONE (FROM MAP) 4

TOTAL DOUBLE-PANE WINDOW AREA

(SQUARE FEET) 132

TOTAL SINGLE-PANE WINDOW AREA

(SQUARE FEET)TOTAL WALL AREA (SQUARE FEET)TOTAL ROOF/CEILING AREA (SQUARE FEET)TOTAL DOOR AREA (SQUARE FEET)R-FACTOR OF EXISTING WALL INSULATION

R-FACTOR OF EXISTING ROOF/CEILINGINSULATION

Heat Loss Profile DisplayedENERGY-EFFICIENCY IMPROVEMENT PLANADD WALL INSULATIONADD ROOF/CEILING INSULATIONINSTALL STORM WINDOWSCAULK AND WEATHER STRIP

ADDED R-FACTOR OF NEW INSULATION

Heat Loss Profile with Plan DisplayedPercent Heat Loss Reduction Displayed

TOTAL ANNUAL HEATING COST 900

Annual Savings in Heating CostDisplayed

find your heating zonefrom figure 2

using the worksheet,find the area of all ex-

66

posed surfaces

3002

"

1500

"

42

"

9

measure the existing in-

sulation thickness

and find the R-factor from

20

table 1

(see figure 3a)

(enter 1)

(enter 2)

(enter 3)

(enter 4)

1

choose plan 1, 2, 3, or 4

9

find R-factor of insulation

to be added from tabe 1

(see figure 3b)

(see figure 3b)

the existing insulation cannot beexactly determined either. Also,dampness and uneven thickness willalter the heat-transfer properties ofinsulation.

In short, some assumptions arenecessary in this program to expressthe heat-loss characteristics of thehome. For most houses, however, theevaluation provided in this programis reasonably accurate for selectingthe best heating energy-conservationplan and determining the approxi-mate saving in heating costs. ■

add last year's heatingbills—total annual cost

(see figure 3b)

Figure 4: An annotated representation of the information requested by the program inlisting 1. Data for the sample house is given.

Several publications are avail-able from the US government toaid in conserving home heatingenergy. Among them are:

Building Science #64

Retrofitting Existing Housing for

Energy ConservationMaking the Most of Your Energy

Dollars

These and other publicationscan be obtained by contacting theUS Department of Commerce, Na-tional Bureau of Standards,Washington DC 20230. Your localpower utility company and yourhome heating fuel supplier mayalso be able to provide you withliterature.

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Circle 218 on Inquiry card.

260 October 1981 © BYTE Publications Inc

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Circle 118 on inquiry card.

BYTE October 1981 261

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Your computer talks to our computers. Youneed a modem and some special software.Software for the TRS-80* and Apple II®computers are available at many Radio Shack*outlets and all Radio Shack® ComputerCenters. Atari® users can access the systemvia Telelink™ software. Persons owning otherbrands of computers or terminals can alsopurchase the CompuServe Information Servicethrough Radio Shack®. In more than 260U.S. cities you can reach the CompuServeInformation Service via a local phone call. Thecost is $5 per hour, billed in minutes, to yourcharge card, for service between 6 PM and5 AM local time on weekdays and all day onSaturday, Sunday and most holidays. Limiteddaytime access is available at a higher rate.

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There are more than 175 topics listed in theon-line index. Most first-time users areinterested in:

1. News, weather, sports. We offer theelectronic editions of many of the majordaily newspapers and the AP news andsports wires.

2. CB simulation. "Talk" to other computerusers anywhere in the country. We alsooffer electronic mail.

3. Games. Many, including the multi-playerSpace War, Star-Trek, four Adventuregames.

4. Finance. Again, a wide variety for bothhistorical and current data on stocks, bondsand commodities.

5. Computer user groups (including nationalbulletin boards) and computermanufacturers' newsletters.

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When you are ready, CompuServe InformationService can provide you with a lot of bigmainframe computer power. But see ademonstration at Radio Shack® right away soyou can get on-line before the tournament.

Radio Shack and TRS-80 are trademarks of TandyCorporation. ATARI and Telelink are trademarks of ATARI,Inc. Apple is a trademark of Apple Computer, Inc.

Circle 79 on inquiry card.

BYTE October 1981

263

Bridging the 10-Percent Gap

Paul T Brady

91 Marcshire Dr

Middletown NJ 07748

In my spare time, I'm the ad-ministrator of a nature center in Mid-dletown, New Jersey. We have a staffof five, an annual budget approach-ing $40,000, a mailing list of 1500names, annual attendance of 10,000visitors, and a need to type and/ormimeograph letters, handouts, andother literature. (If you wonder howwe can support five people on$40,000, we can't; some staff mem-bers are on the payroll of other agen-cies.)

And if you were wondering what anature center has to do with com-puters, take a minute to think aboutthe figures in the first paragraph.You'll soon see that we were absolute-ly hurting for a small computer.

This article describes our problemsand eventual success in computeriz-ing many of the office functions at thenature center. It's one of many similarstories, I'm sure. But there are alsomany small businesses like ours, in-cluding grocery stores, museums, lawoffices, and other firms, that couldbenefit from computers—but won'tbecause of the 10-percent gap.

The 10-Percent Gap

I make two claims:

1. There is already available a widerange of excellent hardware at rea-sonable prices that can perform thefunctions a small business requires.

2. There is also an enormous range ofavailable software that will almost

do the required job. It will do a90-percent job. But to bridge the10-percent gap requires experienceand efforts far beyond the abilitiesor interests of the typical small-business owner. This 10-percentsoftware gap is holding back a vir-tual explosion of data processinginto small businesses.

Background

My computer work began in 1958,programming the TX-0 computer atMIT in machine language (what else).I have sampled many other com-puters and languages, generally usingminicomputers and microcomputers.By profession, I work at Bell Labs andspecialize in performance measure-ments of mid-size systems, especiallyVAX/VMS systems (made by DigitalEquipment Corporation). I also spentmany years designing and testinghuman-factor interfaces to computersystems.

The nature center grew from a citi-zens' movement in 1969 to save landfor a park. We succeeded, and nowhave a fine 250-acre park with histor-ic buildings and a new nature center.The name of the park is PoricyPark (an Indian name from the1600s). It is operated by a citizens'committee with an excellent profes-sional staff—who have absolutely nobackground in computers.

We Needed Help!

The first warning that we needed

data processing came from our in-ability to manage our mailing list byhand. Just try hand-addressing 1000envelopes! So I wrote a program toprint labels from a name-and-addressfile and put it on a timeshared system.For many years, this program got oc-casional use whenever we had a mail-ing.

But there were problems. The com-puter system was often down formodifications, especially in the eve-ning hours when we usually used it. Itwas not available to our staff, we hadno dial-up equipment, and we oftenwouldn't have daytime access even ifwe could dial in. But the most seriousproblem was that I was the only per-son in the world who knew how touse the system. If anything happenedto me, good-bye mailing list. Wefinally realized that we had to becomeself-sufficient, and that several peoplehad to be able to manage the list.

The second need for a computerwas realized soon after we opened thepark year-round. Our accountingsystem, managed in part by nonex-pert secretaries and in part byvolunteers, was a real headache. Weoften met at nights, pounding on anadding machine generating yards oftape, trying to find minor errors inentering checks or locating missingdeposit entries. The annual tax-returntime was a nightmare, when weusually had to plow through every-thing again.

264 October 1981 © BYTE Publications Inc

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Searching for a Solution

In early 1979, we came up withpartial specifications. We had to fitthe mailing list on one floppy disk;this demanded either 8-inch disks or5-inch quad-density disks. We neededan impact printer with adjustabletractor feed (for labels), and, if possi-ble, of letter quality for secretarialwork. Finally, we needed a video ter-minal; we did not care whether it wasseparate or incorporated into themain computer. We had no need forvideo graphics or color, so we coulduse any standard terminal.

We began by visiting a computerstore, a nicely decorated operationwith impressive-looking equipment.We were greeted by a friendly sales-person who asked what we wanted.After we explained who we were andwhat we needed, he immediately toldus they had the solution. This so-called solution was a $15,000 systemwith bells and whistles, a dot-matrixprinter, etc, far out of our price rangeand probably not even suitable. Afterfinally getting down to a system wemight be able to handle, we engaged

in dialogue such as:

Clerk: "Suppose you wanted to playchess."

Us: "We don't want to play chess."Clerk: "But suppose you do."Us: "We don't. We want to do ac-counting and mailing-list manage-ment."

A little more of this and we got tosee the manager. We asked if theBASIC system, or any other systemthat came with the machine, haddecimal floating-point arithmetic, as

October 1981 © BYTE Publications Inc 265

opposed to binary floating-point.(Binary floating-point can haveround-off error on fractions, in-tolerable in accounting. Until recent-ly, most microcomputer systems rep-resented numbers only in integer orbinary floating-point format.) Themanager answered that their systemshad great precision, certainly enoughfor dollars and cents. We explainedthat we were not talking about preci-sion, the number of digits supported,but the way decimal fractions were

stored internally. The manager gotangry and condescending; we got dis-gusted. No sale.

The next few months producedsimilar encounters. All dealersclaimed to have just what we wanted,except that they never bothered toask us what we wanted to do with it,or anything at all about our business.This is one of the fundamental prob-lems of dealers. Because they spendso much time talking to computerfreaks, they assume everybody wants

What Causes the Gap?

What causes the gap between soft-ware technology and business applica-tions? One reason commonly cited iscomputer scientists' preference to de-velop new theories and exploreabstract concepts, rather than developapplication techniques.

This is illustrated by the "Letters"column in the December 1980 BYTE.There is a letter about a language thatwill generate a program that willreproduce itself. There's another aboutstack problems. There's a whole sec-tion of comments on the FORTH ar-ticles in the August issue. There's evensomeone who wants to hear moreabout SNOBOL. (Now there's anoldie!) It's clear there are some prettysophisticated readers out there.

In my profession as a computer-sys-tems analyst, I often interviewcomputer-science graduates. It is acommon lament among interviewersthat all we get are people who (1) wantto design a new compiler, or (2) wantto build an operating system. They aretaught the mathematical beauty ofstack-oriented languages, or list pro-cessors, and so on, and would be rightat home with those who wrote the let-ters to BYTE.

I am certain there's a place for pureprogramming in our society, but Ithink the real prizes will go towhoever can make computersunderstandable and useful tobusinesses.

The Twain Must Meet

The first part of the solution is togive people the necessary background.Train them in night school, and traintheir children in grade school. Don'ttrain them how to build self-reproducing programs (unless theyreally want that), but train them in

business applications of computers.

It may be possible to establish ascience of computer applications. It iscertainly a challenge to write a newlanguage or operating system, but it isalso a challenge to develop a disciplinethat studies applications. How manycomputer-science graduates know theelements of accounting? How manyhave studied business administration?These people are very bright, and ifthey are exposed to the practical prob-lems businesses encounter, they maydiscover that applications is itself achallenging problem.

We need better standards of com-mercial software. I am convinced thata common language is hopeless;BASIC comes as close as any, but com-puter scientists get ill when it is men-tioned. (I can empty a room by stating:"BASIC is my language, and GOTO ismy favorite instruction." MentioningCOBOL also produces some prettyneat reactions.) Perhaps we cannot set-tle on a standard language, but at leastit should be one that is widely ac-cepted.

Software should be easy to modifyor expand. Maybe I am old-fashioned,but I prefer to get source code; itwould have saved me hours with ourNorth Star system. At least, tables oftransfer vectors and interface hooksshould be documented.

Perhaps what we will eventuallycome to is an industry, already beingestablished, of businesses that special-ize in installing software for other busi-nesses. It may be similar to the auto-service industry. I have no idea how tofix a car, yet I buy one with some con-fidence that my local mechanic (who Ihappen to think is pretty good) cantake care of whatever happens. Theanalogy is far from perfect, butperhaps it helps make the point.

to play with systems, languages, andvarious gadgets. We don't. Our busi-ness is running a nature center—not acomputer center.

Because dealers spend

so much time talking

to computer freaks,

they assume everybody

wants to play withsystems and languages.

Our System

Eventually, from the wide range ofequipment and operating systemsavailable, we arrived at our currentconfiguration. It includes.-

• a North Star Horizon computerwith 48 K bytes of memory and twoquad-density disk drives (each diskhas 360,000 bytes)

• a Perkin-Elmer Bantam terminal

• a beautifully reconditioned Perkin-Elmer Carousel printing terminal,donated by the Perkin-Elmer Cor-poration (whose computer division isin the town adjacent to the park;clearly a special case for them to dothis)

Some of the equipment was pur-chased with special private grants.No membership funds were used. Iemphasize this because we have not,unfortunately, reached the pointwhere contributors think positivelyabout using their donations for acomputer. Typewriter, yes; com-puter, no. Let's hope this attitudesoon changes.

We are very pleased with theequipment, but many other manufac-turers would do as well. There ismuch fine hardware on the market.

The main problems occur in thesoftware. There's plenty of soft-ware—but virtually none of it bridgesthe 10-percent gap.

Why Software Is Inadequate

Here are some reasons why com-mercially available software was un-suitable for our business:

1, It is too complex. I purchased themanual for an accounting program,

266

October 1981 © BYTE Publications Inc

High resolution, dotaddressable graphics withvertical resolution of 72 dotsper inch and up to 82 dotsper inch horizontalresolution.

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The 88C provides a selectable 11x7 serif styledot matrix for correspondence printing.

Cost Effective

The 88C has more features than any otherimpact printer in its price class. First comparethe quality of the 88C, then compare the price-the 88C wins! Single unit price is less than$800.

'Optional

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Circle 252 on inquiry card

BYTE October 1981

267

Photo 1: 77ie nature-center computer system consists of a Perkin-Elmer Bantam ter-minal, a Perkin-Elmer Carousel printer, and a North Star Horizon computer.

but decided it was overkill for oursmall business. Many files were ma-nipulated, 5-digit account numberswere used, and fairly elaborate formswere produced. All these were waybeyond our needs or ability to han-dle. In another example, most word-processing systems are fine for profes-sional secretaries or typists, but theyhave a bewildering array of features.In one popular text editor, virtuallyevery key on the keyboard assumes aspecial escape role in editing. You caninsert, search, delete, search anddelete, reformat, and on and on.

2. Much of it is too expensive. Weare a small, nonprofit corporation;we barely managed the funds re-quired for the hardware. We simplycannot spend hundreds or thousandsmore on software.

3. The programs are incompatiblewith each other. The key used forcorrecting errors is BACKSPACE in

one program, DELETE in another; inone program, you specify line range 2through 35 as "2,35" and in another,as "2:35"; the letter "s" stands for"save file" in one program, "w" isused to "write" (save) in another. Ourstaff would never be able to keepthese straight. Some vendors areovercoming this problem by offeringcomplete packages. This is a step inthe right direction.

4. The commercial software is nearlyimpossible to modify. Much of it isshipped as machine-language mod-ules. I have years of bit-picking (orbit-twiddling) behind me, and I stillfind no beauty in deciphering a mem-ory dump. Or the program is inPascal, or C, or whatever, and wedon't have a compiler for that lan-guage.

5. Many programs require diskchanges and other potentially danger-ous procedures to run them. If profes-

sional system managers sometimesget disks mixed up, what aboutnature-center employees?6. The most important reason of all:the programs don't do what we re-quire. Thus, even if we received apackage of compatible programs, allwith the same human-factor inter-face, we would still have to makemany modifications to suit our needs.I'll illustrate this with two examples:the salary program and the mailing-list manager.

A Salary Package

A salary program is very useful.Employees work odd hours. Some arepaid weekly, some hourly. Deductionstatus for an employee might changeduring the year. Part-time workerscome and go. Income tax W-2 formshave to be prepared every year. It'snice to automate this.

An advertisement offers a "power-ful, flexible payroll program. Federal,state, Social Security, etc, withhold-ings are automatic." But we havesome local obstacles.

New Jersey has an unemploymentand disability tax that affects only thefirst $7500 of income on a per-personbasis. This threshold is crossed at dif-ferent times by different employees.Mary Smith's year-to-date wages lastweek were $7404; this week they were$7581. We have to recognize that$7500 was crossed, and tax only theproper fraction of the week's pay.The $7500 figure changes as statepolicy changes. Does the "powerful,flexible payroll program" handle thistax? [ Various other states have excep-tional procedures that create prob-

^wesMAffnN

McGraw-Hill Bookstore

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Please print clearly.

Design and Strategy"for Distributed Data Processing

toy James Martin

"The man generally acknowledged to be thecomputer Industry's most widely read au-thor, best attended lecturer, and foremostauthority on the social and commercial im-pact of computers." - Computer World"Distributed processing is here to stay andwill change the way hardware and softwareare Implemented. "-James MartinHere is clear strategy and illustrated techniques ofgood design for distributed processing. The authorskillfully builds understanding of the complex tech-nology. 637 pp. $37.50

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268 October 1981 © BYTE Publications Inc

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fl ffl^

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Circle 385 on inquiry card

BYTE October 1981 269

lems for general-purpose payroll pro-grams.... RSS]

The workmen's-compensationaudit usually requires salary to be ac-counted between arbitrary dates,such as February 1 to August 20. Canthe package handle that?

No matter what package is offered,we will find something we need that isnot included.

The Mailing-List Manager

Many mailing-list managers are of-fered. They usually contain variousfixed fields, a few including specialkeying fields. Surely we could use oneof these.

Probably not. We had eight years'experience with our first mailing-listprogram and developed a long wishlist for the next one. We don't handlejust names and addresses. We handlememberships. We want to recordcontributions and remarks. If JackArmstrong donated an enlarger forthe darkroom, we want to recordthat. We might want a list of all peo-ple who have contributed since lastSeptember. Or all those who con-

tributed last year, but not this year.Or everyone who gave more than$50. New contributions have to beeasy to enter, and an automatic purgeshould be done on very old contribu-tions to keep the file size reasonable.Key fields should allow "ORing"categories, such as "volunteers orpatrons." The program must printlabels, give statistical analyses of con-tribution records, and have internalchecks on zip code validity.

If such a program is marketed, wedidn't find it. And these requirementsare not at all unusual—they are whatany business such as ours wouldreasonably require.

Software Development

In the fall of 1979, uncertain howmuch software we could purchaseand what it would do for us, we re-ceived our North Star computer. Itcame with BASIC, DOS (the NorthStar disk operating system), and afew memory utilities such as diskcopy, hexadecimal or ASCII dump,etc. There was no machine-languageassembler or disassembler (symbolic

dump), nor was there a text editor.

Since we had no funds for suchsoftware, I began playing withBASIC and found that I liked it verymuch. Best of all, it allowed direct ac-cess to memory with FILL and EXAM(POKE and PEEK) and raw key-board input of characters, essentialfor picking up special control keys.

We ended up coding all of our soft-ware ourselves. Each program wasfirst outlined and discussed withother computer people and thenature-center staff. Each took a fewweeks to write and document. Bysummer 1980, we had the followingprograms:

• a text editor

• a program to record field trips weran, with attendance, date, etc, andan analysis feature to yield summarystatistics over any time span for alltypes of trips

• a payroll program

• a general-accounting package, witha wide range of features, has alreadysaved untold hours of volunteer andstaff time

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270 October 1981 © BYTE Publications Inc

Circle 139 on inquiry card.

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Corp.

EXORdltr is a tradtmark of Motorola

Circle 67 on inquiry card.

BYTE October 1981

271

Circle 82 on Inquiry card.

If you're looking for

the best pricesin the U.S.A. oh

MICROCOMPUTERS

We have consistently offered theTRS-80 line at savings up to 20%. Youcan save up to S1500 by buyingfrom Computer Discount of America.

ATARI*

MICROCOMPUTERS

We have the full line of ATARI per-sonal computers and systems.Model II26-4002 64K. 1 disc $3385.00

Model III

26-1061 4K, Level I $ 610.00

26-1062 ,6K. Level III $ 845.00

26-1066 48K. Level II 2-drive/RS-232 $2115.00

Color Computer

26-3001 4K $ 329.00

26-3002 16K w/Ext. Basic $ 499.00

EPSON

MX70 Primer $ 375.00

MX80 Printer $ 485.00

MX80FT Printer $ 639.00

Our savings are as big on expansioninterfaces, printers, diskettes, AppleComputers, OKIDATA Microline,C-IT0H Starwriter, Lexicon Modems— everything for your computer.We have the largest inventory in theNortheast, and most models are instock, for immediate delivery.Our full price catalog or a pricequote is as near as your phone.

CALL TOLL FREE:800-526-5313

Computer

of America

COMPUTER DISCOUNT OF AMERICA. INC.15 Marshall Hill Road. West Milford MallWest Milford. New Jersey 07480In New Jersey Call 201-728-8080

• a label program, which handles anynumber of files, and prints names, ad-dresses, and optional comments in listor label form, is used for special mail-ing lists, such as the list of volunteers

• a main mailing-list program that, asalready mentioned, also keeps trackof contributions

Operating-System Changes

The 10-percent gap exists not onlyfor commercial-application pro-grams, but also for languages and op-erating systems. The North Star soft-ware comes with several pages ofdocumentation on how to makechanges to suit your hardware orother special requirements. Thesewere useful, but the beginning pro-grammer might have difficultyunderstanding the functions of thesechanges. However, some changes wehad to make were not documented, asin the following example.

After writing the text editor andgetting it to work with the video ter-minal, I tried it with the printer. Itstarted off all right, but carriagereturns suddenly began to be insertedat seemingly random places in thetext. This made the editor unusable,so I had to find what was causing thereturns and suppress them.

The problem turned out to be in theoperating system. I fixed it in anafternoon with hardware boots,hexadecimal object-code dumps, andsome trial and error. It's the kind ofthing that turns on a computer buff,but not the manager of a naturecenter.

Computer 1, Staff 0

When the editor and a few otherprograms were completed, it wastime to introduce the computer to thestaff. It was a rather difficult firstmonth. But to judge from my ex-perience with human factors andcomputers, it was no different fromany other first encounter of inex-perienced people with computers.

The initial problems were severebut were quickly cured. The worstone involved the inability of peopleto differentiate which program andwhich mode they were working in.People would give BASIC commandsto the operating system (such as

"RUN") and receive puzzlingresponses (in this case, "7"). Whenthey finally got into a program Iwrote, I expanded on the error mes-sages, but they ignored them any-way. The most common error in theeditor was typing text when com-mands were expected (ignoring thecommand prompter) and vice versa(ignoring a text prompter). Trainingand much practice overcame this.

But the most persistent problem,which still exists to a small degree, isgetting people to grasp the concept offiles. Assume the editor is used tocreate a file "turtle." The next day,our secretary enters the editor andreads the file "turtle." She modifies itand, instead of writing it back to "tur-tle," writes it instead to "shell."

Any experienced user of systemslike these will realize there are nowtwo files on the disk: "turtle" and"shell." But not the novice. Thenovice thinks the editor somehowworked on the file "turtle" and refiledit under "shell." In other words, oursecretary views the system as a filingcabinet in which a folder was takenout, worked on, and put somewhereelse.

The confusion was compoundedwhen "turtle" was read in, "shell" wasread in and appended to "turtle," andthe result was written to either of theold files or even a new one, "egg."The problem arises because a novicedoesn't realize the computer actuallyworks on a special memory or tem-porary file. The novice insists that thecomputer is working on "turtle" or"shell " and will not accept the con-cept of working on this merged filethat really has no name and no directcorrespondence to any file on thedisk.

Some computer-oriented friendssuggested an interesting scheme to ex-plain the file concept. We obtainedseveral decks of playing cards andhad everyone stand around a tableholding five or six cards. I sat at thetable playing the role of the com-puter. Each player's hand was a file,with the name of the player. Webegan with file "barbara." Instead ofputting her cards on the table, Icopied them, dealing myself an iden-tical hand from another deck. I then

272 October 1981 © BYTE Publications Inc

Q. What do these dealers have in common?A. They sell Tarbell quality products.

ALABAMA

"Jett Consulting

1312 Brookmeade St.

Huntsville 852-4364ARIZONA

Thought Works

3532 W. Thomas Rd. #2

Phoenix 271-9098

S-100 Inc.

14425 No. 79th St. Suite B

Scottsdale 991-7870

Telegraphic Computer

2113 S. 48th

Tempe 998-3163'Ozymandias Systems

976 S. 5th

Yuma 783-4315NORTHERN CALIFORNIA

Jaynes Eleclronics

135 So. Bolinger Rd.

Visalia 733-2515

National ComputerCenter, Inc.

3038 No. Cedar Avenue

Fresno 227-8479

Argos Computer

790 W. Shaw Ave. Suite 360

Fresno 221-7211

D & W Digital

1524 Redwood Drive

Los Altos 966-1460

Electrolabs

930 Emerson Avenue

Palo Alto 321-5601'Digital Graphics Systems

935 Industrial Ave

Palo Alto 856-2500

Support Systems

1157 Chess Drive. Suite G

Foster City 349-2340•PKG Systems

1755 Arlington

El Cerritos 235-5261

Computer Store ofSan Leandro

701 MacArthur Blvd.

San Leandro 569-4174

Computers West

1300 Creekside. Suite 319

Walnut Creek 944-9431

Buchla Associates

1740 Arch Street

Berkeley 848-0790

Queue Computer Corp.

1044 University Avenue

Berkeley 845-5300'Bell Controls

270 Prospecl Drive

San Rafael 924-2990'Aaron Enterprises

790 Pine Lane

San Rafael 479-4268

Computer People

20 Oak Grove Ave.

Woodacre 488-0992

Data Comm Engineering

720-D Capitol Avenue

Capitola 475-3540■RCS Inc.

2116 Walsh Avenue

Santa Clara 244-4505

System Technology

100 A Mt. Hamilton Rd.

San Jose 251-8002

Microbyte Computer Store

2798 So. Bascom

San Jose 377-4685

Electronic Systems

5B69 Winfield Blvd.

San Jose 226-4064'Joe Bergin

4354 Vulcan Drive

Sacramento 486-8033SOUTHERN CALIFORNIA'Versacomp

3016 Waverly Drive #303

LOS Angeles 666-4447'Omega Enterprises

921 N. La Jolla Ave.

Los Angeles 656-7388

Cal Blu Corporation

350 S. Figueroa Street

Suite 389

Los Angeles 617-2185

Applied ProcessorLaboratories

11808 So. Prairie Ave.

Hawthorne 676-8940'California Digital

4738 W. 56th Street

Lawndale 679-9001

*SAS Computer Products

11766 Sunset Blvd.

Pacific Palisades459-5674'Query ComputingSystems Inc.

4812 La Villa Marina Suite F

Marina Del Rey 823-5959

Futra Co

3447 Torrance Blvd.

Torrance 370-1589'Computer Place

2530 West Sepulveda

Torrance 325-4754'Computer Galaxy

14112 San Antonio

Norwalk 863-8008'Brown Dog Engineering

P.O. Box 427

Lomita 326-8482

Culbertson & Associates

14611 Leahy

Bellflower 920-7438

Action ComputerEnterprise

55 W. Del Mar Blvd.

Pasadena 793-2440"Dynatron International Co.

9514 Reseda Blvd.. Suite 8

Northridge 881-8700

Hobbyworld Electronics

19511 Business Center Dr.

Northridge 886-9200'Elliam Associates

24000 Bessemer St.

Woodland Hills 348-4278'Computer World

58/8 Sepulveda Blvd.

Van Nuys 786-7411

Data Vector Corporation

2412 N. Keystone St.

Burbank 842-2866'Astar International Co.

5676 Francis Avenue

Chino 284-0561

Richard Chew

2020 Crown Circle

La Verne 596-3480

E.D.P. Management

5465 Lake Murray Blvd. #D

La Mesa 462-5400

Byte Shop

8038 Clairemont Mesa Blvd.

San Diego 565-8008

Computerland

4233 Convoy Street

San Diego 560-9912

The Computer Center

8205 Ronson Rd.

San Diego 292-5302'CTC-The Computer People

5560 Ruffin Road

San Diego 565-0505'Bits n Bytes

679 D. So State College Bl.

Fullerton 879-8386

InternationalScientific USA. Inc.

679 S. State College Blvd.

Suite E

Fullerton 870-9491'DMM Software

11502 Janette Lane

Garden Grove 534-0115'Scharf Office Systems Inc.

8562 Acapulco

Huntington Beach963-2730'WEH Computer Systems

8481 Grace Circle

Huntington Beach964-4425

Cotton Associates

1278 Glenneyre #16

Laguna Beach 499-2994

Computer Systems andApplications

965 No. Main Street

Orange 535-3335

Byte Shop

123 E. Yorba Linda Blvd.

Placentia 524-5380

Advanced ComputerProducts

1310 B. East Edinger

Santa Ana 558-8813'L. Electronics

410 Bell Avenue

Santa Ana 557-6796•Computers Plus

1827 State Street

Santa Barbara 963-4542

COLORADO

'Epsilon14501 E. Alameda, Ste. 204Aurora 344-0874Business Data Systems1688 30th StreetBoulder 444-3652

CONNECTICUT

Office Services ofHamden Inc.965 Dixwell AvenueHamden 624-9917

FLORIDA

Applied Microcomputer

Technology Inc.241 Old Dirt RoadTallahassee 878-3385'Quaray Devices1033 N. E. 8th AvenueGainsville 373-7959'Matthew-Douglas

Assoc. Inc.

1337 E. Altamonte DriveAltamonte Spring

830-9611

Byte Shop of Ft. Lauderdale2176 W. Oakland ParkFt. Lauderdale 486-2983Erdman Computer Services2454 N.E. Dixie HighwayJensen Beach 334-3366'Microcomputer

Technology1549 W. Brandon Blvd.Brandon 685-6714

GEORGIA

ElectromagneticSciences Inc.125 Technology ParkNorcross 448-5770

'Advanced ComputerTechnology6540 Roswell RoadAtlanta 255-8984Computerland of Atlanta2423 Cobb ParkwayAtlanta 577-2449

'H & L Electronics5144 Peachtree RoadAtlanta 455-0626HAWAII

"Kahaluu Computing47-500 KamKaneohe 239-7267Mahalo Microsystems Ltd.355 Royal Hawaiian Ave.Honolulu 922-2152Small Computer Systems3140 Waialae AvenueHonolulu 732-5246

Lillipute Computer Mart

4446 Oakton Street

Skokie 674-1383'MidwestMicrocomputers Inc.

708 S. Main Street

Lombard 495-9889

Bies Systems Inc.

7037 West North Avenue

Oak Park 386-3323

Byte Shop

7 So. La Grange Road

La Grange 579-0920'Wilcox Enterprises

25 W. 178 - 39th St.

Naperville 420-8601INDIANA

Computer ConsultingServices

4801 N. Michigan

Indianapolis 638-5330'Smith Computer Systems

530 Pierce Avenue

Dyer 322-5461

Data Domain

2805 E. State Blvd.

Fort Wayne 482-8415'Data Domain

221 West Dodds

Bloomington 334-3607"Digital Supply

617 Agathon Drive

Evansville 985-3677

Digital Technology

10 N. 3rd

Lafayette 423-2548KANSAS

Computer Center

5815 Johnson Drive

Mission 432-2983LOUISIANA'Great Southern ComputerSystems

915 Talbot

Thibodaux 446-6432

Computer Electronics

1955 Dallas Drive

Baton Rouge 924-8066MARYLAND•R2D2 Enterprises

8232 Bernard Drive North

Millersville 987-4471MASSACHUSETTES'The Computer Mart Inc.

1395 Main Street

Route 117 at 128

Wallham 899-4540'Scientific ConsultingServices

4 Lovell Road

Watertown 926-4046•William J. Claff

7 Roberts Rd.

Wellesley 235-9505

Computer Shop

590 Commonwealth Ave.

Boston 247-0700

MICHIGAN

Spectrum Computers26618 Southlield RoadLalhrup Village 559-5252Unique Business Systems28783 Greenfield RoadSouthfield 559-6300Lyben Computer Systems27204 Harper

St. Clair Shores 777-7780GAW Computertronics37727 Amrhein RoadLivonia 464-0441•Jepsan

4180 - 44th Street S.E.Grand Rapids 698-8700

MINNESOTAMicroprogramming Inc.1351 Larc Industrial Blvd.Burnsville 894-3510Microage Computer Store83 South 10thMinneapolis 338-1777

NEW JERSEY

'Olcott International & Co.

62 Hackensack Plank Rd.

Weehawken 863-4200

Computer Emporium

Bldg. 103Avenues of Commerce

Cherry Hill 667-7555'Financial Software

54 Grove Street

Haddonfield 795-5607'A B Computer Products

236 W. County Line Road

Jackson 493-8047

William Electronics Supply

1863 Woodbridge Avenue

Edison 985-3700'Computer Mart of NJ Inc.

501 Route 27

Iselin 283-0600

NEW MEXICO

Suntech Systems. Inc.7108 Osuna N.E.Albuquerque 884-8453

NEW YORK

'Owens Associates12 Schubert StreetStaten Island 448-6283DBIS

One Mayfair RoadEast Chester 779-5292L-2 Computers. Inc.86-16 Santiago StreetHollis 479-1400Baranco

32 Goodwin PlaceNorthport 261-0452

'Mini Micro Mart943 W. Genesee StreetSyracuse 422-4467

NORTH CAROLINA

American SquareComputers

4167 Kivett Drive

Jamestown 889-4577'Digital Dynamics Corp

1118 Clement Avenue

Charlotte 374-1527

Southern DigitalSystems Inc.

Vernon Park Mall,Suite 806A

Kinston 527-4691

OHIO'Service Specialist

127 No. Prospect

Oberlin 775-1742'Cycom Corporation

3355 Richmond RoadPlaza 230B

Beachwood 461-0875

Tec Mar Inc.

23600 Mercantile Road

Cleveland 464-7410

Computerland of Cleveland

1288 SOM Center Road

Mayfield Height 461-1200'Cincinnati Computer Store

11711 Princeton Pike

Cincinnati 671-6440

Wholesale/Retail Systems

2705 Lillian Lane

Fairborn 426-8781

RIM Systems

529 S. Hyatt

Tipp City 667-3069

OKLAHOMA

Microlithics Inc.

304 N. Meridian Avenue

Suite 15Oklahoma City 947-5646

OREGONMicro Methods116 S. W. 1st StreetWarrenton 861-1765WRAM Computer

Corporation6450 S. W. Parkhill WayPortland 244-2168'Computerland of Portland12020 S. W. Main StreetTigard 620-6170

PENNSYLVANIA

Erie Computer Company1253 W. 8th StreetErie 454-7652'Marketline Systems Inc.2337 Philmont AvenueHuntington Valley947-6670Computer Methods523 Hansen RoadKing of Prussia 265-2580

TENNESSEE

'Ace Mini Systems Inc.

1598 Ft. Campbell Blvd.Trade Winds North

Clarksville 645-3632"American Systems Inc.

1805 Hayes Street

Nashville 327-0277

Aiken Computer Systems1302 River Oaks DriveFlower Mound 436-9155

•The Micro Store634 S. Central ExpresswayRichardson 231-1096Northwest Datacomm1174 Commerce DriveRichardson 669-1816The K.A Computer Store9090 Stemmons FreewayDallas 634-2667Data Time Systems1212 Main Street. Suite 110Houston 658-8572

'Altech Controls Corp.13995 Murphy Road,Building 412Stafford 499-5697R & T Henry ElectronicAssembly613 Pemberton DriveChannelview 452-4451

'Microtronics, Inc.2720 WestwardLa Marque 935-5020

VIRGINIA

American Computer &Telecom

11301 Sunset Hills Road

Reston 471-6288'Xener Corporation

Suite 211

6641 Backlick Road

Springfield 569-5050

Computers Plus

6120 Franconia Road

Alexandria 971-1997

Computer Center

2927 Virginia Beach Blvd.

Virginia Beach 340-1977

WASHINGTON'Innovative Computing. Inc

19820 - 60th Avenue N.E.

Seattle 487-2448

Seattle Computer Products

1114 Industry Drive

Seattle 575-1830

Forest Sales

820 - 4th Street

Anacortes 293-5154

Olympic Computers

418 S. Lincoln

Port Angeles 457-3315WEST VIRGINIA

The Computer Store Inc.

Suite 5

Municipal Parking Bldg.

Charleston 345-1360

Associated ComputerConsultants

1332 Pine View Drive

Morgantown 599-2319'The Computer Corner. Inc.

22 Beachurst Avenue

Morgantown 292-9700WISCONSIN

DMA Inc.

545 Meadow Lane

Sheboygan Falls 467-6006

Byte Shop of Milwaukee6019 W. Layton AvenueGreentield 281-7004Magic Lantern Computers3313 University AvenueMadison 233-2026

OUTSIDE U.S.A.

TE' and Company207 Yoko Heights

39 Okuma-ChoMidorku Yokaha 226 Japan(045) 473-3171Canadian Microcomputer

Sys Assoc Ltd.1188 Main StreetSmithers

B.C. Canada 20J 2N0(604) 847-4838The Patent OfficeHurricane HoleP.O. Boxes 5586Nassau. Bahamas(809) 323-1371Compex2 Gerls Vej.

2300 Copenhagen Denmark01-520494

'Jarrod Electronics Inc.349 Silverstone DriveRexdale Ontario CanadaM9V 3J8 (416) 745-6458Microboards1-7-1-1003 Saiwai-ChoChiba City, Chiba 260 Japan0427 (47) 3081'Microtech Computers745 Martin AvenueWinnipeg. Manitoba(204) 667-5395J.T. Microcomputers109 Kooringal AvenueThornleigh.

NSW Australia 2120(02) 8480452Cesco Electronics Ltd.4050 Jean Talon St. W.Montreal

Quebec Canada H4P 1W1(514) 735-5511Computer Centre9 De-La-Beche StreetSwansea. South Wales

SA1 3EX0792460023

"Dealers who sell Tarbell EMPIRE series computers.

Circle 358 on inquiry card.

#18 SOFTWARE

ULTIMATE SOFTWARE PLAN

We'll match any advertised priceon any item that we carry. And ifyou find a lower price on what youbought within 30 days of buyingit, just show us the ad and we'llrefund the difference.It's that simple.

Combine our price protectionwith the availability of full profes-sional support and our automaticupdate service and you have theUltimate Software Plan.

It's a convenient, uncomplicated,logical way to get your software.

ARTIFICIAL INTELLIGENCE

Medical(PAS-3) $849/$40

Dental (PAS-3) $849/$40

ASYST DESIGN

Prof Time Accounting. .$549/$40*> General Subroutine. .. $269/$40

• Application Utilities.... $439/$40COMPLETE BUS. SYSTEMS

Creator $269/$25

Reporter $169/$20

Both $399/$45

COMPUTER CONTROL

Fabs(B-tree) $159/$20

UltraSortll $159/$25

COMPUTER PATHWAYS

Pearl (level 1) $ 99/$25

Pearl (level 2) $299/$40

• Pearl (level 3) $549/$50

DIGITAL RESEARCH

CP/M 2.2

NorthStar $149/$25

TRS-80 Model II (P+T)$159/$35

Micropolis $169/$25

Cromemco $189/$25

PL/l-80 $459/$35

• BT-80 $179/$30

Mac $ 85/$15

Sid $ 65/$15

Z-Sid $ 90/$15

Tex $ 90/S15

DeSpool $ 50/$10

D.M.A.

Ascom $149/$15

DMA-DOS $179/$35

CBS $369/$45

Formula. . $539/$45

GRAHAM-DORIAN

General Ledger $729/$40

Acct Receivable $729/$40

Acct Payable $729/$40

Job Costing $729/$40

Payroll II $729/$40

Inventory II $729/$40

Payroll $493/$40

Inventory $493/$40

Cash Register $493/$40

Apartment Mgt $493/$40

Surveying $729/$40

Medical $729/$40

Dental $729/$40

MICRO-AP

S-Basic $269/$25

Selector IV $469/$35

MICRO DATA BASE SYSTEMS

HDBS $269/$35

MDBS $795/$40

• DRSorQRSorRTL...$269/$10

MDBS PKG $1295/$60

MICROPRO

WordStar $319/$60

Customization Notes...$ 89/$na

Mail-Merge $109/$25

WordStar/ Mail-Merge. $419/$85

DataStar $249/$60

WordMaster $119/$40

SuperSortl $199/$40

• Spell Star $175/$40

y (New items or new prices)

CP/M users: specify disk systems and formats. Most formats available.

MICROSOFT

Basic-80 $289/$na

Basic Compiler $329/$na

Fortran-80 $349/$na

Cobol-80 $574/$na

M-Sort $124/$na

Macro-80 $144/$na

Edit-80 $ 84/$na

MuSimp/MuMath $224/$na

MuLisp-80 $174/$na

ORGANIC SOFTWARE

• TextWriter III $111/$25

DateBookll $269/$25

• Milestone $269/$30

OSBORNE

General Ledger $ 59/$20

Acct Rec/Acct Pay.... $ 59/$ 20

Payroll w/Cost $ 59/S20

All 3 $129/$60

All 3 + CBASIC-2 $199/$75

PEACHTREE'

General Ledger $399/$40

Acct Receivable $399/340

Acct Payable $399/$40

Payroll $399/$40

Inventory $399/$40

Surveyor $399/$40

Property Mgt $799/$40

CPA Client Write-up. . .$799/$40

• P5 Version Add $ 129

SOFTWARE WORKS

Adapt (CDOS to CP/M]. $ 69/$na

Ratfor $ 86/$na

SOHO GROUP

MatchMaker $ 97/$20

Worksheet $177/$20

STRUCTURED SYSTEMS

GL or AR or AP or Pay.. $599/$40

Inventory Control S599/S40

Analyst $199/$25

Letteright $179/$25

QSort $ 89/$20

SUPERSOFT

Diagnostic I $ 49/S20

Diagnostic II $ 84/S20

Disk Doctor $ 84/$20

• Forth (8080 or Z80) ... $ 149/S30

Fortran $219/$30

Fortran w/Ratfor $289/$35

Other less 10%

TCS

GLorARorAPorPay. $ 79/$25

All 4 $269/$99

UNICORN

• Mince $149/$25

• Scribble $149/$25

• Both $249/$50

WHITESMITHS

"C" Compiler $600/$30

Pascal (incl "C") $850/$45

"DATA BASE"

FMS-80 $649/$45

dBASE II $629/$50

Condor II $899/$50

Access/80 $749/$50

PASCAL"

Pascal/MT+ $429/$30

Pascal/Z $349/$30

• Pascal/UCSD 4.0 $429/$50

• Pascal/M $ 189/$20

"WORD PROCESSING"

• WordSearch $179/$50

SpellGuard $229/$25

VTS/80... $259/$65

Magic Wand $289/$45

Spell Binder $349/$45

"OTHER GOODIES"

The Last One $549/$95

SuperCalc $269/$50

Target $189/$30

BSTAM S149/S15

• BSTMS $149/$15

Tiny"C" $ 89/$50

Tiny "C" Compiler $229/$50

CBASIC-2 $ 98/S20

Nevada Cobol $129/$25

• MicroStat S224/S25

Vedit $105/$15

MiniModel $449/$50

StatPak $449/$40

Micro B+ $229/$20

Raid $224/$35

String/80 $ 84/S20

String/80 (source) $279/$na

• ISIS II $199/$50

• Plan 80 $269/$30

INFO UNLIMITED

EasyWriter $224

Datadex $349

Other less 15%

MICROSOFT

Softcard (Z-80 CP/M). $259

Fortran $179

Cobol $499

MICROPRO

Wordstar $269

MailMerge $ 99

Wordstar/MailMerge. $349SuperSortl $159

PERSONAL SOFTWARE

Visicalc 3.3 $159

CCA Data Mgr $ 84

Desktop/Plan II $159

Visiterm $129

Visidex $159

Visiplot $149

Visitrend/Visiplot $229

Zork $ 34

PEACHTREE"

General Ledger $224/$40

Acct Receivable $224/$40

Acct Payable $224/$40

Payroll $224/$40

Inventory $224/$40

"OTHER GOODIES"

dBASE II $329/$50

• VU #3R

(usew/Visicalc) $ 79

Super-Text II $127

Data Factory $134

DB Master $184

Charles Mann less 15%

STC less 15%

ORDERS ONLY-CALL TOLL FREE VISA • MASTERCHARGE

1-800-854-2003 ext. 823 • Calif. 1-800-522-1500 ext. 823

Overseas—add $10 plus additional postage • Add $2.50 postage and handling per each item • California

residents add 6% sales tax • Allow 2 weeks on checks, C.O.D. ok • Prices subject to change without notice.

All items subject to availability • ® —Mfgs. Trademark.

THE DISCOUNT SOFTWARE GROUP

6520 Selma Ave. Suite 309 • Los Angeles, Ca. 90028 • (213) 666-7677

Int'l TELEX 499-0032 BVHL Attn: DiscSoft • USA TELEX 194-634 BVHL Attn: DiscSoft •

TWX 910-321-3597 BVHL Attn: DiscSoft

modified my hand (the computer-memory file), all the while pointingout that nothing was happening toher hand. I then copied the new fileback to her hand, changing it. Or Icopied it to someone else's hand. Weconcatenated hands, wrote them todifferent files, and did a variety ofthings that simulated what computersdo.

It worked! This exercise went along way in clearing up the confu-sion, and I heartily recommend it toothers. But don't let drop-in visitorsget the wrong idea about what you'redoing with the cards!

A Happy Ending

A few months after our staff's firstencounter with the computer, thingshad settled into a steady state, andthe staff was using it productively. Atthat point, one of the principal users,a secretary, left to help her husbandin a small business. (No, they don'thave a computer—yet.) The newsecretary arrived, and I fully expectedto have to start all over with training.

I was wrong. I spent almost no timeat all. Instead, the other staff mem-bers trained her. How's that for a self-reproducing system7

Some of you might think that ahappy ending to this story would beto say that our system continues togrow, we are finding more and moreuses for the system, hope to expandto a Winchester-technology hard-diskdrive, recode everything in ... (Wow,did I almost open Pandora's box!),and look toward a national networkfor nature-center data communica-tions.

Perhaps some of these things willoccur. But in the meantime, we arequite content with the system. I havestopped coding, except for minor im-provements, and can now spend mytime outdoors finding wild flowersand mushrooms. The staff treats thecomputer as a piece of standard officeequipment, and they welcome thetime it has saved them. As our direc-tor put it, "We once thought it was anunnecessary complication, and nowwe depend on it." She might haveadded, "And we take it for granted."What happier ending could this storyhave?B

274 October 1981 © BYTE Publications Inc

Circle 128 on inquiry card.

OUR SECOND GENERATION DP-NET

We at Delta Products have been involved in 'NETWORKING SYSTEMS' for thepast eighteen months. During this time we delivered our first net systems to beta testsites. These closely monitored field installations provided invaluable data, whichDelta Products has incorporated into the design of our second generation of

DP-NET systems. - Tin ^^^^^H^H

SECOND GENERATION OP-NET

The S-4500 DP-NET system will support from one to ten users, and provideeach with their own Z-80 CPU and 64Kof ram memory. Each user will alsohave access to 40 megabytes of harddisk storage, 17.2 megabytes of filemanaged tape backup, and floppydisk.

TRUE RECORD & FILE LOCKOUT

iy simply reading in the entire recordor file you wish to protect, the DP-NETSK SELECTIVE LOCKOUT' guar-antees complete data integrity. TheDP-NET also allows the use of today'spopular micro applications languages(i.e., Cbasic®, Mbasic®, Cobol®, etc.),without having to compensate for theproblems inherant to these languagesin the multi-user environment, whilemaintaining CPM compatibility.

INTERACTIVE FAMILY OF SYSTEM

S-4500

v

The S-4500 is but one of many DP-NET configurations utilizing parallel and/or serialcommunication links. Delta Products also manufacturers a wide range of conven-tional single and multi-user systems operating under CP/M and MP/M. Single andulti-user systems can be upgraded to DP-NET's, because their basic componentsare utilized in our network systems. We have intentionally developed an interactivefamily of systems that are completely configurable and compatible, never limitingthe ability to adapt to a modification in the application. Delta Products systems areavailable thru a worldwide network of selec-tive distributors and dealers. Call for thename and number of the one nearest to you.

Circle 83 on inquiry card

System Notes

Discover the MachineBeneath the Machine

A ZX80 Monitor Program

R Scott FitzGerald, 570 NW Walnut, Corvallis OR 97330

The most powerful instructions of Sinclair Research'sZX80 BASIC interpreter are PEEK, POKE, and USR.These instructions allow access to the machine beneaththe machine by letting you examine, modify, and executethe ZX80's natural language: Z80 machine code.

The Z80 instruction set has all the functions of the8080 set, plus some extremely powerful commands of itsown: block transfers, extensive bit manipulation andtesting, indexed and displaced addressing, relative jumps,and programmed I/O (input/output). Besides the 8080registers, the Z80 has a duplicate register bank and twoindex registers, an interrupt-vector register, and adynamic-memory-refresh register. This adds up to apower-packed microprocessor "under the hood" of yourZX80.

So why bother programming in BASIC when Z80machine language is only a POKE away? One reasonmay be that the tedium of entering an endless string ofPOKE statements to run a machine-language programdiscourages you from venturing outside BASIC.

In this "System Note," I present a monitor program,written in ZX80 BASIC, that gives you the power

Programming Aids for the ZX80

The following items are available from The SofTekCompany, POB 4232, Santa Fe NM 87501:

A quick-reference guide for the ZX80 computer thatincludes error codes, programmable-memory usage,character set, the Z80 microprocessor instruction set,and a couple of applications programs. Item numberZX80QRG. Price $1.95.

Two dozen BASIC programs for the ZX80, in-cluding games, Z80 machine-language programmingaids, graphics, finance, string manipulation, andmathematics. Item number ZX80PGM. Price $5.95.

to examine and modify memory using octal notation andto execute Z80 machine-language programs. The pro-gram MONITOR is designed to run on a ZX80 systemwith a minimum of 1 K bytes of programmable memoryand a 4 K-byte interpreter. After you enter MONITOR ina 1 K-byte system, you will still have enough memory leftfor a machine-language program more than 150 byteslong.

Listing 1 shows the program MONITOR. When run,MONITOR displays:

OCTAL MONITOR

and the prompt MODE? on the video screen. You thenhave three choices. You can:

• enter a 1, which will cause a branch to the EXECUTEroutine

• enter a 2, which will result in a branch to the EX-AMINE/MODIFY routine

• enter a 3, which will result in an exit from MONITORto the BASIC interpreter

The program uses octal numbers for data input and out-put because this is the natural number base for use withthe Z80 op codes.

Here are MONITOR'S modes explained in greaterdetail:

• Mode 1: EXECUTE. A 1 response to the MODE?prompt permits execution of the machine-language rou-tine you have loaded into memory. Execution will beginat the decimal address specified in response to the STARTADDR?(DEC) prompt. The machine-code routine shouldend with a RET (return) instruction (octal 311) to let themonitor regain control; otherwise, you'll literally have topull the plug to return the computer to your control. Pull-ing the plug will erase MONITOR and your machine-code program as well.

278 October 1981 © BYTE Publications Ire

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The Grappler™ Interface is the first universal parallel interface card to provide sophisticatedon-board firmware for Apple high resolution graphics. No longer does the user need to loadclumsy software routines to dump screen graphics — it's all in the chip. Actually, it's our E-PROM,and there are versions to accommodate the Anadex, Epson MX100, MX80*& MX70, IDS PaperTigers, Centronics 739, and future graphics printers. The Grappler™ accepts 18 simple softwarecommands accessible through the keyboard or user program, making it the most intelligent Apple

interface available.

FEATURES

SELECT PAGEINVERSE GRAPHICSDOUBLE SIZE PICTURE90° ROTATIONCENTER GRAPHICSCHART RECORDER MODE ■BLOCK GRAPHICS

BELLMARGINSSKIP-OVER-PERF.VARIABLE LINE LENGTH

TEXT SCREEN DUMP

'Requires Graftrax-80

USER BENEFIT

Choice of Hi-Res Graphics page 1 or page 2

Provides reverse graphics of black-on-white, or white-on-black

Doubles the graphic screen representation vertically & horizontally

Rotates the screen picture 90°

Accomplished through setting left margin thereby centering the graph

Successive horizontal pictures are combined continuously simulating a chart recorder

— For printers with block graphics (e.g. Epson MX80, Okidata M80), the high order bit canbe controlled

— For printers with a bell, bell characters are deleted during user program listings

— Set left and right margins

— Set page length; printer will automatically skip 6 lines between each page

— For user program listings, sets line length and wraps around with breakpoint at nearestblank

— The text from a user report or page of program listing can be dumped directly from thescreen

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DEALER INQUIRIES WELCOME

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Circle 281 on inquiry card.

System Notes,

• Mode 2: EXAMINE/MODIFY. In mode 2, you can ex-amine and modify locations in memory, starting at theaddress you specify after the START ADDR?(DEC)prompt. This routine displays the address and its con-tents in octal and waits for your input. If you input an oc-tal number from 000 to 377, it will replace the previouscontents of that location (assuming that you are not ad-dressing read-only memory). If you enter a — 1, theroutine will go on to the next byte in memory withoutmodifying anything. Any number outside the —1 to 377range will terminate the EXAMINE/MODIFY routineand display the MODE? prompt again.

• Mode 3: EXIT. Entering 3 in response to the MODE?prompt lets you exit the monitor, and control returns tothe ZX80 BASIC interpreter's text-input module. Don'texit MONITOR, however, if you want to keep a validcopy of your machine-language program in memory.Because the ZX80 BASIC interpreter uses a great deal ofmemory to display MONITOR, the display file will prob-ably overrun your machine-language program.

The ability to execute Z80 machine-language programson the ZX80 opens a new dimension to the serious ZX80programmer. I hope that the program MONITOR willgive you easier access to some of the powerful features ofyour ZX80.B

REE

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EDITION

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Listing 1: A machine-language monitor for the Sinclair ZX80.This program lets you examine and modify sequential memorylocations and execute machine-language programs stored inmemory.

10 CLS

20 PRINT "OCTAL MONITOR"

30 PRINT "MODE?"

40 INPUT M

50 IF (M<1) OR (M>3) THEN GO TO 10

60 CLS

70 GO TO 4oo*m

400 PRINT "EXEC"

410 GO SUB 2000

420 PRINT "HL=";USR(S)

430 GO TO 20

800 PRINT "EXAM/MOD"

810 GO SUB 2000

820 LET C=0

830 LET D=S

840 LET N=4

850 GO SUB 3000

860 LET D=PEEK(S)

870 LET N=2

880 GO SUB 3000

890 PRINT ":=";

900 INPUT D

910 PRINT D

920 IF (IX-I) OR (D>377) THEN GO TO 10

930 LT D=-l THEN GO TO 960

940 GO SUB 4000

950 POKE S,A

960 LET S=S+1

970 LET C=C+1

980 IF C~16*(C/16)=0 THEN CLS

990 GO TO 830

1200 STOP

2000 PRINT "START ADDR?(DEC)";

2010 INPUT S

2020 PRINT S

2030 RETURN

3000 FOR K=0 TO N

3010 LET Q=D/(8**(N-K))

3020 LET D=D-Q*(8**(N-K))

3030 PRINT CHR$(Q+28);

3040 NEXT K

3050 PRINT " ";

3060 RETURN

4000 LET A=0

4010 FOR K=0 TO 2

4020 LET Q=D/(10**(2-K))

4030 LET D=D-Q*(10**(2-K))

4040 LET A=A+Q*(8**(2-K))

4050 NEXT K

4060 RETURN

280 October 1981 © BYTE Publications Inc

Circle 386 on inquiry card.

Micro computer softwarecompany gets macro results.

"Software is the hottest segment ofthe personal computer industry.After all, it's the software that solvesproblems. And Business Week hasprecisely the type of readers whoare looking for solutions to thekinds of problems we solve. Top andmiddle management of corpora-tions. That's why right from thestart we committed a substantialportion of our marketing budgetto advertise in BusinessWeek.And we're very pleased with theresults. Since our first insertion,our monthly sales have morethan doubled."

James M. Dow, President

Microcom, Inc.

When Microcom beganin 1980, the Boston-basedmanufacturer of personal com-puter software wanted tospread the word to corporate

managers about its first product—an electronic mail pack-age for Apple™ computerscalled Micro-Courier™ Notonly to managers who alreadyhave Apples,™ but to the fast-growing market of managers incorporations who are thinkingof buying personal computersto help them and their staffsdo a better job.

For Microcom's Jim Dow,Business Week brought hismarket into focus. BusinessWeek has a take-action audi-ence of over 6 million cor-porate decision makers. Andthey look to Business Week tokeep them informed on com-puter developments. BusinessWeek is the only general busi-

Circle 50 on inquiry card.

ness publication with an entireeditorial section, InformationProcessing, covering eventsand trends in the computerindustry. Every week.

As Microcom found out,one of the best times to linkup with Business Week is rightat square one. But for smallcompanies or large companies,Business Week gets big-timeadvertising results. Call yournearest Business Weekrepresentative today.

BusinessWeek

Source: MRI (Spring, '81)/Pub. est.

Print neatly,

so WE KNOW

WHERE TO SENDYOUR CHECK.

282 BYTE October 1981

Buying new software is the pits,isn't it?

You read an ad and it soundsterrific, so you ask around, then buythe manual.

So far, so good—so you springseveral hundred dollars for thepackage.

And it does exactly what theysaid. But to get exactly what youwant, you're going to have to changethe way you run your business. Orgo through so much hassle thatyou're not sure it's worth it.

So you grit your teeth and suffer,or put it on a shelf to gather dust.

Sounds familiar, doesn't it?

But there is at least one knownexception: an exceptional DBMScalled dBASE II.

For database fans, an offeryou shouldn't refuse.

dBASE II is the only high-performance j^lational DatabaseManagement System for micros.And it's the only DBMS that canhelp you get the DBMS that's rightfor you, no matter which DBMSyou may want. Here's how:

If you have a 48k micro withCP/M, send us its model numberand the size of your drives alongwith $700 (CP/M 86 version soon-call if you can't wait).

We'll send you a copy of dBASE IIthat you can run on your system,solving your problems your way,for 30 days. Then just send every-thing back and we'll return yourmoney, no questions asked.

During that 30 days, you can findout how much a real databasemanagement system can do for you.How it will affect your operations.Exactly what you want done. Andprecisely how you want to do it.

Then even if you go for someother system, you'll be an informedbuyer.

And it never hurts to know whatyou're doing.

IBM just caught up.So can you.

With dBASE II, you'll get thesame kind of system for your microthat IBM introduced a few monthsago for their mainframes.

It's a relational DBMS, and thatmakes it different from any othermicro system you've ever seen.

In a relational database, the datais organized as simple tables, withrecords as the rows and the datafields as the columns, much like yourdata is organized now. Data rela-tions are logical, so that you canzero in on the specific informationyou want without knowing a thingabout the pre-defined sets, pointersor other cumbersome structures ofhierarchal and network DBMS's.

And unlike file managementsystems, dBASE II gives you pro-gram and data independence. Youcan change your database structurewithout re-entering your data andwithout reprogramming, or changesome or all of your programs with-out touching your database. Andthe same database can be used forany number of different applications.

dBASE II is a stand-aloneapplications developmentsystem.

You don't need an extra supportlanguage, because dBASE II comeswith its own Applications Devel-opment Language (ADL). With ADL,you can use simple English-likestatements to manipulate your data,or use built-in structured constructsto prepare sophisticated applica-tions packages. It's simple and easyto use, yet extremely powerful.

You create a new database andstart using it in a minute or less.Just type CREATE, then respond tosystem prompts to name the file anddefine the fields. Now enter the data.

Add data to an existing databaseinstantly, whether your file has

AshtonTate

\shton-Tate 1981

10 records or 10,000 records, bytyping APPEND, then entering theinformation.

UPDATE, MODIFY, JOIN andREPLACE whole databases orindividual records and characters.

Add or delete fields in your data-base structure without re-enteringall your data.

And with dBASE II, it's easy toget information out once you've putthe data in.

Do automatic calculations onfields, records and databases with afew keystrokes.

Organize months' worth of datain minutes with REPORT (printingoptional), and get your reportstoday instead of tomorrow. Usethe built-in SORT, with single ormultiple keys. Or INDEX yourdata, then FIND it in seconds, evenwith floppies.

You can use dBASE II inter-actively or store a sequence of com-mands to automate your accounting,billing, mailing lists or whateverdata you have to manage.

You'll wonder how youmanaged without it.

dBASE II is the most powerful,easiest to use DBMS you can get fora micro.

And instead of poring over themanual, you can run it hands-on,in-house to see exactly what it cando for you. Try it.

What have you got to lose? Weeven provide the label so you cansend it back.

Ashton-Tate, 3600 Wilshire Blvd.,Suite 1510, Los Angeles, CA 90010.(213) 666-4409.

Circle 33 on inquiry card.

BYTE October 1981

283

Graphics Fundamentals

Kathleen Bresnahan Sandifur

624 Six Flags Dr #130

Arlington TX 76011

To make effective use of any graphics system, youmust first understand the functions universal to all suchsystems. For the neophyte, the only readily availablemethod for mastering graphics concepts is to attack a dis-sertation of incomprehensible detail—an endeavor thatcan be as frustrating as reading the fine print on your in-surance policy.

In this article I try to put some graphics concepts intoperspective. Four subroutines of the Hewlett-PackardGraphics/1000 software package are singled out:WINDW, LIMIT, VIEWP, and SETAR. The terms arepeculiar to the software package, but the concepts areuniversal to all graphics. As a vehicle for conveying theseconcepts, the application program LOGO is presented inthis article.

The LOGO program incorporates the four subroutinesmentioned above to allow easy manipulation of size,shape, and positioning of a logo. By following the imple-mentation of the four subroutines and the explanation ofresults related to parameter changes, the uninitiatedreader can gain an easy grasp of the graphics function.

The underlying objective of all graphics systems is tocapture an image, manipulate it and then project it toanother location or surface. The image must first be pre-sented to the graphics system. For the purpose of the sam-ple program, the image was presented by sketching a logoon a sheet of graph paper, approximating this sketch withstraight line segments, and tabulating the coordinates forthe end points of these segments (see figure 1). The coor-dinates were calculated by arbitrarily setting x and y axesto correspond to the horizontal and vertical lines of the

\

/

/A

/

/

f

/a

/ /

//

1

//

/ /

\\

(L\-

/ /

J

V 1 ! /

Figure 1: Sketch of the logo letters on graph paper establishing xand y coordinates for the line segments that make up the letters.

284 October 1981 © BYTE Publications Inc

1r * -tr -tr -tr -tr-tr -tr-tr -tr * -tr-tr -tr -tr -tr -tr -h A -tr & -tr -lr & •&&& * * * * ir-tt-ir-k-k-tr-tr-A-tr-tr-tr-tr-tr-tr-irlftftr-tr **

4MHZ, DOUBLE DENSITY,COLOR&B/WGRAPHICS. .THE LNW80 COMPUTER

COMPARE THE FEATURES AND PERFORMANCE

When you've compared the features of an LNW80 Computer, you'll quicklyunderstand why the LIJW80 is the ultimate TRS80 software compatible system.LNW RESEARCH offers the most complete microcomputer system at an outstand-ing low price.

We back up our product with an unconventional 6 month warranty and a 10days full refund policy, less shipping charges.

LNW80 Computer $1,450.00

LNH80 Computer w/B&W Monitor & one 5" Drive $1,915.00

All orders must be prepaid, CA residents please include 6* sales tax.Contact us for shipping charges

* TRS80 Product of Tandy Corporation.

** PMC Product of Personal Microcomputer, Inc.

FEATURES

LNW80

PHC-80**

TRS-80*

MODEL III

PROCESSOR

4.0 MHZ

1,8 MHZ

2.0 MHZ

LEVEL II BASIC INTERP.

YES

YES

LEVEL IIIBASIC

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 RS232 PORT

YES

YES

YES

PRINTER PORT '

YES

YES

YES

REAL TIME CLOCK

YES

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 KEY PAD

YES

NO

YES

B/W GRAPHICS, 128 X 48

YES

YES

YES

HI-RESOLUTION B/W GRAPHICS,

480 X 192

YES

NO

NO

HI-RESOLUTION COLOR GRAPHICS128 X 192 IN 8 COLORS

(NTSC),

YES

NO

NO

HI-RES0LUT10II COLOR GRAPHICS384 X 192 IN 8 COLORS

(RGB),

OPTIONAL

NO

NO

WARRANTY

6 MONTHS

90 DAYS

90 DAYS

TOTAL SYSTEM PRICE

$1,915.00

$1,840.00

$2,187.00

LESS MONITOR AND DISK DRIVE

$1,450.00

$1,375.00

—

LNW80

BARE PRIIITED CIRCUIT BOARD s MANUAL

$89.95

LNDoubler&DOS PLUS 3.3D

Assembled and Tested W/DOS PLUS 3.3D $175.00

The LNW80 - A high-speed color computer totally compatible withthe TRS-80*. The LNW80 gives you the edge in satisfying yourcomputation needs in business, scientific and personal computa-tion. With performance of 4 MHz, Z80A CPU, you'll achieve per-formance of over twice the processing speed of a TRS-80*. Thismeans you'll get the performance that is comparable to the mostexpensive microcomputer with the compatibility to the world'smost popular computer (TRS-80*) resulting in the widest soft-ware base.

FEATURES:

TRS-80 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 RAM, 12K Bytes ROM

Solder Masked and Silkscreened

LNW SYSTEM EXPANSION

BARE PRINTED CIRCUIT BOARD

AND MANUAL $69.95

WITH GOLD CONNECTORS $84.95

The System Expansion will allow you to expand your LNW80, TRS-80*,or PMC-80** to a complete computer system that is still totallysoftware compatible with the TRS-80* Model 1 Level II.

Double-density disk storage for the LNW Research's "System Expan-sion" or the Tandy's "Expansion Interface". The LNDoubler™ istotally software compatible with any double density softwaregenerated for the Percom's Doubler***. The LNDoublerTM providesthe 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. Easy plug in installation requiring no etch cuts, jumpers

or soldering. 35, 40, 77, 80 track 5" disk operation. 120 day parts and labor Warranty

*** Doubler is a product of Percom Data Company, Inc.

DOS PLUS 3.3D

Micro Systems software's double density disk operating system.This operating system contains all the outstanding features ofa well developed DOS, with ease in useability.

KEYBOARD

LNW80 KEYBOARD KIT $84.95

The Keyboard Kit contains a 63 key plus a 10 key, P.C. board, andremaining components.

CASE

32K Bytes Memory

5" Fluppy Controller

Serial RS232 20ma I/O

Parallel Printer

Real Time Clock

Screen Printer Bus

On Board Power Supply

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LNW80 CASE $84.95

The streamline design of this metal case will house the LNW80,LWN System Expansion, LNW80 Keyboard, power supply and fan,LNDoubler™, or LNW Data Separator. This kit includes all thehardware to mount all of the above. Add $12.00 for shipping

PARTS AVAILABLE FROM LNW RESERARCH. 4116 - 200ns 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

LNW80 "Start up parts set"LNW80 "Video parts set"LNW80 TransformerLNW80 Keyboard cable

LNW80-1 $82.00

LNW80-2 $31.00

LNW80-3 $18.00

LNW80-4 $16.00

40 Pin computer to expansion cable $15.00

System Expansion Transformer $19.00

Floppy Controller (FD1771) and UART (TR1602) . . . $30.00

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graph paper. This process is a form of digitization and isonly one of the many methods available. All have the ob-jective of conveying information in a form recognizableto the graphics system. Coordinates representing the logoare entered at lines 33 to 101 of the sample program (seelisting 1). Once the image is made available to the system,the process of capturing the image, manipulating it, andprojecting it involves four steps:

• Determine the boundaries surrounding the image to becaptured (WINDW).

• Set the limits of the device to the boundaries of thepaper or transparency to be used (LIMIT).

• Determine the boundaries within which the image is tobe projected on the paper or transparency (VIEWP).

• If you don't want the projected image distorted, thenthe window surrounding the image and the viewport onthe projecting surface must both have the samewidth/height ratio (SETAR).

WINDW

When the graphics system receives the digitized repre-sentation of the image, it needs a frame of reference todesignate where the image to be captured is located. Togenerate this reference frame or window, the WINDWsubroutine is invoked. The general form of WINDW is:

CALL WINDW(IGCB,X1,X2,Y1,Y2)

where (XI,Yl) designates the lower-left corner of the rec-tangular window and (X2,Y2) designates the upper-rightcorner. Because this rectangle is to frame the image or aportion of the image represented in the digitization pro-cess, the parameters for the WINDW subroutine must begenerated from the same axes, units, and origin used inthe digitization process (the ones established on the graphpaper).

The setting of the WINDW parameters in line 29 of thesample program to:

CALL WINDW(IGCB,0.,355.,0.,130.)

specifies that the lower-left corner of the rectangular win-dow is zero units in the x direction and zero units in the ydirection (at the origin on the graph paper). Also, theupper-right corner of the window is at 355 units in the xdirection and 130 units in the y direction (to the far rightand middle of the graph paper). Since the window en-compasses the entire logo "TDC," the captured image forgraphics manipulation will be the entire logo. If, how-ever, the window had been specified by:

CALL WINDW(IGCB,200.,355.,0.,130.)

then the window would frame only the "C" portion of thelogo, and only that image would be available for graphicsmanipulation.

286 October 1981 © BYTE Publications Inc

^H

i>

v PH

■ami

L^irj

Bpffijj

Maxell Floppy Disks. Class of '81.

Not a single dropout among them.

These are the disks that achieve all you expect fromthem. They are certified free of dropouts. And eachone meets or exceeds the most demanding specifica-tions every computer authority can set. That includesISO, IBM, ECMA, ANSI, JIS and Shugart.

The quality begins with the finest raw materialsavailable, and we make sure the quality stays high.Every Maxell floppy disk must pass an exhaustive seriesof eight quality control inspections. Under test condi-tions, after 10,000,000 passes, there is no loss of quality.

Maxell Floppy Disks actually help protect yourcomputer drive heads. The self-cleaning jacket liner

inside every Maxell disk removes dust before it canaffect your system. The surface lubricant reduces anychance of disk-caused head-wear.

There are Maxell disks for every disk drive system inoperation today. Maxell is leading the way with newdisk technology for tomorrow's computers. Your MaxellBusiness or Maxell Personal Computer Products suppliercan put our "honor-grad" to work for you, and for yourcomputer, now and in the future.

Call or write for more information. You'll learn thatthe care we take manufacturing Maxell Floppy Disksmakes them live up to your highest expectations.

maxell

Maxell Corporation of America, Business Products Division, 60 Oxford Drive, Moonachie, N.J. 07074. (201) 440-8020

Circle 214 on inquiry card.

Listing 1: LOGO, the program used to produce figures in this article. The program is written to run on a Hewlett-PackardGraphics/1000 system.

S111A T=00004 IS ON CR00023 USING 0001ft PLKS R=0000

0001 FTN4.L

0002 PROGRAM LOGO

0003 C

0004 C THIS PROGRAM DRAWS A LOGO "TDC" (KATHLEEN SANDTFUR 10*79)

0005 C

0 006 DIMENSION IGCB ( 192) , IBUF f 10) , XLUT (5)» V (U) . rt («). G (2) , XL (4)

0007 EQUIVALENCE (Lib IBUF),fID,IBUFf10))

0008 C

0009 C ESTABLISH ID AMD LOGTCAL UNIT FOP PLOTTER

0010 C

0011 LUT = LOGLUm

0012 WRITECLUT.on

0013 01 FORMATC'ENTFR LU, I D : *" 1

0014 READ(LUT,*) LU,ID

0015 C

0016 C INITIALIZE PLOTTER R SFLFCT PEN

0017 C

0018 CALL PLOTRCIGCB,ID,1,LU)

0019 CALL PEN(IGCB,2)

0020 C

0 021 C ***************************************************************

0022 C * REFERENCES IN ARTTCLF TO LIMIT, SETAP, VTEWP, WINDW *

0023 C * REFER TO THF FOLLOWING CALLS *

0024 C ***************************************************************

0025 C

0026 CALL LIMIT(IGCB|XL(l)#XLf2).XLC3).'XLU))

0027 CALL SETARCIGCB,AR)

0028 CALL VIEWPCIGCB,V(1)»V{?) ,vm ,Vf*))

0029 CALL WI'\IDW(IGCBrWfl).W(?),W(3),«)(fl))

0030 C

0031 C ********* DRAW "T" ************************

0032 C

0033 CALL M0VECIGCB.22..0.)

0034 CALL ORAWCIGCB,82.,105.)

0035 CALL DPAWdGCB, 1 19., 1 05.)

0036 CALL DRAWCIGCB,131..126.)

0037 CALL ORAWCIGCB,12.,126.)

0038 CALL D*AH(IGCBfO.,105.)

0039 CALL DRAWCTGCB,60.,105.)

0040 CALL ORAWfTGCB,0.,0.)

0041 CALL DRAWCIGCB,22.,0.)

0042 C

0043 C ********* DRAW "D" ************************

0044 C

0045 CALL MOVEUGCB,70..o.)

0046 CALL DRAWCIGCB,178..0.)

0047 CALL ORAWCIGCB, 185. . "< . )

0048 CALL ORAWCIGCB,190.,8.)

0049 CALL ORAWCIGCB,193.,15.)

0050 CALL DRAWCIGCB,194.,?0.)

0051 CALL ORAWCIGCB,193..25.)

0052 CALL DRAWCIGCB,192..30.)

0053 CALL ORAWCIGCB,190. ,34.)

0054 CALL ORAWCIGCB,142.,126.)

0055 CALL ORAWCIGCB,70.,o.)

0056 C

0057 C ********* INNER "D" START LEFT "OTTOM ****

0058 C

Listing 1 continued on page 290288 October 1981 © BYTE Publications Inc

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BYTE October 1981

289

Listing 1 continued:

005900600061006200630064006500660067006800690070007100720073

007a

007500760077007800790080008100820083

oo«a

008500860087008800890090009100920093009a009500960097009800990100010101020103

oioa

01050106

CALL MOVECIGCB,102..20.1CALL DRAWCIGCB,142..90.1CALL DRAWCIGCB,175..27.1CALL DRAWCIGCB,176..25.1CALL DRAWCIGCB,175..23.1CALL DRAWCIGCB,173.,21.1CALL DRAWCIGCB,170.,20.1CALL DRAWCIGCB,102..20.1

********* DRAW "C" START LEFT BOTTOM ***********

CALLCALLCALLCALLCALLCALLCALLCALLCALLCALLCALLCALLCALLCALL

9999

MOVEDRAWD R A WDRAWDRAWDRAWDRAWDRAWDRAWDRAWDRAWDRAWDRAWDRAW

CIGCBCIGCBCIGCBCIGCB(IGCBCIGCB(IGCBCIGCBCIGCBCIGCBCIGCBCTGCBCIGCBCIGCB

,203.,,202..,201..,203..,255.,,260.,,265..,270..,275..,285..,291.,,29a.,,290.,>285..

10.1

13.1

17.1

26.1

1 1 A . 1

123.1

125.1

126.1

1 26.1

122.1

115.1

10 5.1

90.1

7a.i

********* INNER "C" START LEFT UPPER *****

CALLCALLCALLCALLCALLCALLCALLCALLCALLCALLCALLCALLCALLCALLCALL

CALLCALLSTOP

END

DRAWDRAWDRAWDPAWDRAWDRAWORAWDRAWDRAWDRAWDRAWDRAWDRAWDRAWDRAW

CTGCfi(IGCBCIGCPCIGCBCTGCB(IGCBCIGCB(IGCB(IGCB(IGCB(IGCB(IGCB(IGCB(IGCB(IGCB

.267,,275,

,27a,

,272,,270,,267,

,?2a,,223,

,22a,,225,

,351,

,3ao,

,215,,210,,203.

,74.1

,100.

, 1 13.

,10 4.

. 105.

. 1 04.

.29

.25

,23

.21

,20

,0.1

.1 .1

.3.1

, 10.1

PEN (IGCB,0)PLOTRCIGCB,ID,01

LIMIT

The LIMIT subroutine defines the view surface on thedevice—in other words, the surface within which allgraphics must occur. After deciding on the size of thepaper or transparency desired, the width and height di-mensions are used to delimit the view surface via theLIMIT subroutine. The general form of LIMIT is:

CALL LIMIT(IGCB,X1,X2,Y1,Y2)

with the x and y units specified in millimeters. As a result,all graphics must now occur within an area bounded in

the horizontal direction from XI mm to X2 mm, and inthe vertical direction from Yl mm to Y2 mm, with theorigin corresponding to the lower-left corner of the de-vice view surface.

In the sample program, a logo is to be projected to a15-inch by 10-inch sheet of paper (380 mm by 250 mm).Line 26 of the program would incorporate these dimen-sions as LIMIT parameters as follows:

CALL LIMIT(IGCB,0.,380.,0.,250.)To further illustrate the use of the LIMIT subroutine, if

290 October 1981 © BYTE Publications Inc

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you want to confine graphics to an 8Vi-inch by 11-inch(215 mm by 280 mm) area, set LIMIT parameters asfollows:

CALL LIMIT(IGCB,0.,215.,0.,280.)

VIEWP

Within the view surface set by LIMIT, the image can berestricted to a desired area. In other words, the logo canbe spread across the entire paper or transparency, or con-fined to only a small area. A viewport designates a rec-tangular portion of the view surface to which the imagein the window is to be mapped. The VIEWP subroutinedefines the positioning of the viewport, and its generalform is:

CALL VIEWP(IGCB,X1,X2,Y1,Y2)

where (XI,Yl) designates the lower-left corner of theviewport and (X2,Y2) designates the upper-right corner.The x and y axes correspond to the lower edge and theleft edge, respectively, of the LIMIT-designated view sur-face.

The units for x and y vary according to the aspectratio, or the ratio of the width to the height of the viewsurface. If the aspect ratio, abbreviated AR, is greaterthan 1, the horizontal length of the view surface cor-responds to 100 X AR units, and the vertical length cor-responds to 100 units. If AR is less than 1, the verticallength corresponds to 100/AR units and the horizontal

length to 100 units. When CALL LIMIT is not initiated,the view surface defaults to the limit of the device, whichfor the HP 9872A has an AR of 1.52. Therefore, to posi-tion a viewport to cover the upper-right quadrant of theview surface, specify VIEWP as follows:

CALLVIEWP(IGCB,76.,152.,50.,100.)

The entry of the viewport parameters in the sample pro-gram occurs at line 28.

SETAR

At this point in the graphics explanation, the processcan be visualized as taking a snapshot and projecting thecaptured image onto a screen. Everything within the rec-tangular window is mapped through the rectangularviewport for positioning on the viewing surface, whichitself has been delimited via the LIMIT subroutine.

If the rectangular window and the rectangular view-port have the same shape (if the aspect ratio is the same),the image can be transferred point for point withoutdistorting any geometric figures. The relative size of im-ages will change, but a circle will remain a circle, andangles between intersecting lines will not change. If theaspect ratio of the window is not the same as that of theviewport, then the image projected on the view surfacewill be distorted: a circle will become an ellipse, and theangle between intersecting lines will change. To alleviate

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292 October 1981 © BYTE Publications Inc

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BYTE October 1981 293

this problem when coverage of the largest possible por-tion of the selected view surface is desired, the subroutineSETAR (set viewport aspect ratio) is used. The generalform for SETAR is:

CALL SETAR(IGCB,AR)

To implement SETAR, calculate the AR for the window.The AR for the window encompassing the entire logo is2.73 (355/130 = 2.73). This value is incorporated at line27 of the sample program as follows:

CALL SETAR(IGCB,2.73)

As a result, instead of a point-for-point mapping of theimage in the window to the viewport, the mapping is nowfrom the window to a reconfigured viewport which hasthe aspect ratio selected by SETAR.

This new viewport is shrunk in size so that it just fitsinside the old viewport while maintaining an AR corre-sponding to the window. After shrinking the new view-port to fit inside the old viewport, one dimension of theold viewport will have unused area. The new viewport iscentered along this dimension. The image in the window,therefore, will be mapped undistorted to an area withinthe originally specified viewport, centered along onedimension and totally filling the other dimension. Thisprovides the largest undistorted projection of the image

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onto the delimited view surface without requiring unduecalculation for viewport positioning.

Parameter Changes

A brief and simplified explanation of each of the foursubroutines has now been presented and the location oftheir implementation in the LOGO program specified.The following will document how individual changes inthe subroutine parameters correlate to output changesfrom the program.

1. Set window to encompass the logo; and defaultLIMIT, SETAR, and VIEWP parameters.

CALL WINDW(IGCB,0.,355.,0.,130.)

The resulting output is a recognizable, although dis-torted, projection of the logo covering the total viewingsurface (see figure 2). The projection covers the totalviewing surface because of the default mode for LIMITand VIEWP. Because CALL LIMIT was not initiated, theviewing surface defaults to the physical limits of the de-vice. For the HP9872A, this is equivalent to the followingat line 26:

CALL LIMIT(IGCB,0.,380.,0.,250.)

Figure 2: The logo translated to fill the entire graph area. Notethe geometric distortion of the letters, which results because theaspect ratio (width/height ratio) of the window and viewportare not equal.

294 October 1981 © BYTE Publications Inc

Circle 157 on inquiry card.

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895.00

CENTRONICS

ni 1 Parallel

995.00

799.95

737 3 Serial

1045.00

899.95

DIABLO (Letter Quality)

630 R102 bi-directional)

tractors

2965.00

2699.00

1640K109 keyboard.

tractors

3072.00

2899.95

630 RO Recleve Only

2710.00

2499.95

1650K 136 keyboard/

tractors

3220.00

2999.95

SAVE

100.00199.00296.00

195.00100.05100.00

195.05145.05

172.05210.05

^

{SPECIAL OF THE MONTH

QSTAR PRESENTSTHE QRAM

16K RAM Expansion Boardfor the Apple II

'»;? I ■ ^

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Expands your 48K Apple to 64K

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Works with Microsoft Z-80 card,

Visicalc, USA ver 2.0 and other

software

Eliminates the need for an Applesoft' or Integer Basic ROM Card

Includes installation and manualFully assembled and testedFULL ONE YEAR warrantyincluding parts and labor

r

APPLE II

STUDENT

SYSTEM

:nu dp

• Apple II PIils System- 4SK BAM

• Disk II Floppy Disk &:Inlcrfai-e(DOS3.3)

• 12 BMC Video Monitor

MONITORS

>

Our

List

Price

NEC Grn Phs 12'

$285.00

S239.99

BMC Green

Phosphorous 1 2

275 00

229.00

SANYO MONITORS

High Resolution, Number 1 seller!

Our

List

Price

13" Color (new)

high quality

$550.00

S388.00

12' Green

Phosphorous

360 00

235.00

12" Black & White

340.00

217.00

15" Black 8c While

370 00

235.00

9" Black 8< White

The Besf Seller!

235.00

145.00

SAVE

$ 46.00

SAVE

$162.00

125.00123.00135.00

DISKETTES

SOLD IN BOXES OF 10

(Min. Purcnasp)

BUY $100 of the

Following Diskettes

List

DYSAN price

104/1 5" SOFT SECTOR S 6 00104/1D =" DBL

DEN -SOFT SEC 6 40

3740H 8" SOFT SECTOR 7 25

3740HD8" DBL.

DEN-SOFT SECTOR 10 75

MAXELLMD-1 5" SOFT SEC-

TOR'DBL DEN 5 00

MD-2 ■" SOFTSECTOR'DBL SIDE DBL

DEN. 7.00

FD-1 8" SOFT SEC'DBL

DEN. 650

FD-2 8" SOFT SEC.'DBL

SIDE'DBL DEN 8 50

MEMOREX5" 3401 5"SOFT

SECTOR 4 40

5" 3420 5" SFT.

SEC.'DBL DEN. 5 60

8" 3060 8" SOFT

SECTOR 540

8" 3090 8" SFT.

SECJDBL DEN. 5.90

.43C1 4.00

PER DISKETTE

3.99

4.604.75

SAVE

S 2.01

1.802.50

4.90

2.10

4.50

2.00

5.95

2.55

AV/.VC.-.S

utvia:i:i.i:crio\

\TISI.\CTIOS

2.55

3.90

3.10

4.102.05

1.85

1.70

2.30

1.801.95,

SOFTWARE

FOR APPLE II

Dow jones PortfolioFolder

Microchess 2.0 ChessDisk

The Controller 1.1General BusinessSystem) (16 Sector)

Apple Post

The Shell Games Ed-ucation I

Elementary, My DearApple-Education II(16 Sector)

Apple How To!Education ill(16 Sector)

Apple Bowl

Apple Writer

DOS Tool Kit(16 Sector)

Dow Jones News &Quotes Reporter(16 Sector)

Apple Stellar Invaders

Apple Plot

Apple Adventure

Apple Music Theory(16 Sector)

Apple Tax Planner(16 Sector)

CassettesInterger Basic Cas-sette Demos (6tapes)

Applesoft CassetteDemos (5 tapes)

Apple Fortran

DOS 3.3 (16 Sector)

Apple PILOT(16 Sector)

SOS Tool Kit(16 Sector)

Apple FORTRAN (re-quires A2B0006)(16 Sector)

Language Systemwith Apple Pascal

Apple III -

Information Analyst

Apple Mail ListManager

Apple Business Basic

Apple System Soft-ware & Manuals

BPI General LedgerSystem

BPI Inventory Package

Vlsidex

Visicalc

Desktop Plan II

Microlab DatabaseSystem

Stoneware DB Master

Programma Apple Pie

Muse Supertext II

Sottape Magici Window

List

50.0025.00

625.0050.00

50.0025.0075.00

95.0025.0070.0035.00

50.00

120.00

25.00200 0060.0U

150.00

75.00

200.00

495.00

500.00

150.00250.00

250.00

$395.00395.00200.00200.00200.00

150.00189.00129.00150 00

99 00

OurPrice

$ 39.0019.00

499.0039.00

40.0019.0060.00

76.0019.0049.0028.00

39.00

19.00147.0045.00

119.00

60 00

159.00

399.00

350.00

130.00219.00

219.00

S319.00319.00159.00159.00159.00

119.00

150.00

97.00

119.00

72.00

SAVE

11.006.00

126.0019.00

10.00

6.00

15.00

19.006.00

21.007.00

11.00

6.0053.0015.00

31.00

9.00

41.00

96.00

150.00

20.0031.00

31.00

$ 76.0076.0041.0041.0041.00

31.0039.0032.0031.00

27.i

oj/

/Vl ICRO BUSINESS WORLD

MICKO T/A.A

i<a

0<> Maui" M«3»l

Ceicnption

„„„ .„«,,

I I

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I I I

L. .

_3E_<rt =!';:»

i.r, nm<.

TAX II APPLICABLE"

SHIPPING 4 HANDLING"CREDIT CARDS ADD W 'TOTAL ENCLOSED S _

1

We reserve the right lo correal typographical errors. This ad supercedes all previous ads.

MAXELL • DYSAN • EPSON • CCS • SHARP • CASIO • HP • VERBATIM • MEMOREX • SOROC • CORVUS • PERSONAL SOFTWARE • ADD

For the projection to cover the entire viewing surface,the viewport must cover the physical limits of the device.This happens by default since a CALL VIEWP was notexecuted. For the HP9872A, this is equivalent to enteringthe following at line 28:

CALL VIEWP(IGCB,0.,152.,0.,100.)

The entire logo is projected because the window chosenwas of the appropriate size and used units correspondingto the units in which the coordinates of the linear segmentapproximation were entered.

The resulting output is slightly distorted because theAR for the window and the viewport differ. The view-port AR defaulted to 1.52 (380 mm wide by 250 mmhigh), and the AR for the window is 355/130, or approx-imately 2.73.

2. Set window to encompass the logo; set viewportaspect ratio to correspond to window aspect ratio(SETAR); and default LIMIT and VIEWP parameters.

CALL WINDW(IGCB,0.,355.,0.,130.)CALL SETAR(IGCB,2.73)

The resulting output is an undistorted projection of thelogo centered in the vertical direction and covering thetotal viewing surface in the horizontal direction (seefigure 3). The entire logo was projected because the win-

STATPRO:

MAINFRAME STATISTICS ON AN APPLE

Statpro is a PASCAL software package designed for the profes-sional researcher seeking solutions with a minimum of effort.

Statpro is grouped into a modular format for sales purposes yetwhich allows the user to transfer data between modules and otherprograms with easy to use prompts.

All Statpro modules include at no extra charge:

(1) Real number data base(3) Questionnaire database(5) General category database(7) Corvus compatibility(9) Does cross tabulation

(2) Data transformations(4) Mailing label database(6) Graphic printing & editing(8) Sample data for firsttime use

Statpro is an integrated database system designed for extensivenumber crunching.

Statpro, unique in being non-memory dependent allows data-bases to be limited in size only by disk space. Statpro can enter,receive, send, sort, and transform data.

Transformations include Arithmetic Logarithmic, Exponential,Trigonometric, Powers & Square Roots, Conversions, RandomNumbers, Standardized Observations and over 40 English toMetric or Metric to English conversions. Statpro contains severalstatistical analysis programs, all interlinked and designed toanalyze the database records.

Among other features, Statpro has extensive color graphiccapabilities, a graphic screen editor, multiple plots per screen,user or computer defined access limits, and choice of symbolsand lines. Printing a graph only takes 30 to 120 seconds dependingon whether the printer is on Anadex, Epson, Paper Tiger or Silen-type.

(send for brochure)

.BLUGlLAKGS'

Blue Lakes Computer

3240 University Ave.

Madison, Wl 53705

(608) 233-6502

dow was determined the same way as in the previous ex-ample.

The projection was centered in the vertical directionand covered the total horizontal view surface because ofthe viewport reconfiguration that occurs when theSETAR routine is implemented. With SETAR set to 2.73,the reconfigured viewport corresponds to a rectanglewith an AR of 2.73 being shrunk until it just fits withinthe old viewport. When a rectangle with a 2.73 AR isshrunk to fit within a rectangle with a 1.52 AR, thehorizontal dimension will be totally filled and the verticaldimension will have unused space.

As prescribed by the SETAR routine, the reconfiguredviewport will be centered in the vertical direction andtotally cover the horizontal view surface. When theimage within the window is mapped to this reconfiguredviewport, it will project an image covering the horizontaldirection and centered in the vertical direction. The re-sulting image is undistorted because the AR of the view-port was designated as 2.73 by SETAR, and the aspectratio for the window was also 2.73.

3. Set window to encompass the logo; set viewportaspect ratio to correspond to window apsect ratio(SETAR); set the physical view surface (LIMIT) to corres-pond to an 8V2-inch by 11-inch viewgraph; defaultVIEWP parameters.

Figure 3: An undistorted projection of the logo verticallycentered and covering the total viewing surf ace in the horizontaldirection. Window aspect ratio is equal to viewport aspect ratio.

296 Oclober 1981 © BYTE Publications Inc

Circle 45 on inquiry card.

... And my dad says GRAFTRAX 80does better graphics than anybody.

Epson.

You might say it's the head of its class. GRAFTRAX 80gives you the highest resolution dot matrix in the world— up to 120 dots per inch horizontally and 216 dots perinch vertically. Which makes our MX-80 and MX-80F/T work more like a plotter than a printer.

And that's just for starters.

GRAFTRAX 80 more than doubles the features avail-able in an Epson MX-80 or MX-80 F/T. For instance,we've added nice little touches like an italic characterset — which doubles the number of font types to 24.And with GRAFTRAX 80, you can change style, sizeand density anywhere in the line. And backspace thehead. And use block graphics with any computer. Andredefine all escape codes under software control.

Up to now, you couldn't get some of these features atany price. With GRAFTRAX 80, you get 'em all. Andmore. Lots more.

Best of all, we haven't forgotten all those people whoalready own an MX-80 or MX-80 F/T. You own theprinter that set the standards all the others are follow-ing. And you can install GRAFTRAX 80 PROMs your-self, for less than $100. And make the best even better.

You can see why we

say GRAFTRAX 80 is

the head of its class.

There's nothing else in

its class.

EPSON

EPSON AMERICA, INC.

3415 Kashiwa Street • Torrance, California 90505 • (213) 539-9140

Circle 147 on inquiry card.

BYTE October 1981

297

Introducing a totally new world

in professional software for the

Apple II and Commodore Pet.

Until recently, the tremendous explosion in micro-computer technology left an unfilled void in realquality software. MicroCraft Systems is totallydedicated to filling that void for the Apple II and theCommodore Pet. With powerful, elegant and ver-satile software.

Beyond the software house. To acomplete 6502 development system.

More than a software distributor or discount house,MicroCraft Systems now provides you with accessto a whole new spectrum in software systems.MicroCraft software includes: MacroLink, a com-plete macroassembler for the 6502, SuperEdit, afull-screen editor with a superb range of powerfulcapabilities plus, DiskScreen, a screen-orienteddisk utility. Complete System $200/$40

MacroLink

$125/$20

Uses text files for source code • Links source codeor object code programs • Fully nestable file in-clude capability • Recursive macros • Nestableconditional assembly • Over 50 error messages •File I/O macros • Sample programs • Disk assem-bler: source code need NOT fit in memory.

SuperEdit

$75/$20

Full Screen Editor • Single keystroke commands •Uses standard text files • Move cursor by character,line or page • Block move and copy • Search andreplace • Macro capability • Plus extra software:SuperEdit '56 x 27' provides 56 x 27 characterscreen for Apple II • And more!

DiskScreen

$40/$10

Displays a complete sector in hex and ASCII • Com-pletely visual and interactive • Sector move andcopy • To change byte value, move cursor and type.

NOTE: All programs require single disk drive. MacroLinkalso requires 48K. First price: software and man-ual. Second price: manual only (applied towardpurchase of software).

Call or write for our complete MicroCraft Systemscatalog at no extra charge. Other programs include:S.T.A.R. Reading Program • "C" Compiler • Gra-phics Development Systems • Programs in ROM •SuperEdit for 80 x 24 video cards

V

MicroCraft Systems, mo.

In software systems, a name to remember.

188 Kerby Road

Grosse Pointe Farms, Ml 48236

(313)881-3089

Source I.D. CL0472

MicroNetl.D. 70270,222

VISA or MasterCharge accepted. Inquire at your localcomputer store or order direct.

CALL LIMTT(IGCB,0.,215.,0.,280.)

CALLSETAR(IGCB,2.73)

CALL WINDW(IGCB,0.,355.,0.,130.)

The resulting output is an undistorted projection of thelogo centered in the vertical direction and covering thewidth of a viewgraph (see figure 4). The restriction of theprojection to an 8V2-inch by 11-inch area located at thelower left of the device results from setting LIMIT.VIEWP is still defaulted to LIMIT, and the other param-eters are the same as for the previous example. As theviewport is shrunk down to fit within LIMIT, it will fillthe viewgraph in the horizontal direction and be centeredin the vertical direction.

4. Set window to encompass logo; set physical viewsurface (LIMIT) to correspond to an SVi-inch by 11-inchviewgraph; set viewport to five different locations (line28); default SETAR.

CALL UMIT(IGCB,0.,215.,0.,280.)CALL WINDW(IGCB,0.,355.,0.,130.)CALL VTEWP(IGCB,6.,40.,6.,18.5)CALL VIEWP(IGCB,40.,94.,6.,25.8)CALL VIEWP(IGCB,6.,70.,100.5,124.)CALL VIEWP(IGCB,70.,94.,116.2,124.)CALL VIEWP(IGCB,20.,80.,25.8,100.5)

AR = 2.73

(Lower left AR = 2.73)

(Lower right AR = 2.73)

(Upper right AR = 2.73)

(Upper left AR - 2.73)

(Center AR = 0.79)

Figure 4: The viewing surface changed to 8V2 inches by 11inches (215 mm by 280 mm). The logo is undistorted, centeredin the vertical direction, and expanded to cover the entire view-ing surface in the horizontal direction.

298 October 1981 © BYTE Publications Inc

Circle 233 on inquiry card.

.••••••••••••

A SELF-COMPILINGRELATIONAL DATABASE

DATABASE SELECTION -

■ Uses screen masks to form query

■ Provides extensive search capabilities

■ Search arguments can include arithmetic/booleanfunctions, multi-field comparisons

■ Queries can generate input for automaticdatabase maintenance

■ Queries can be stored in "Query Library" and executedfrom menu on demand

■ Any number of fields can be queried concurrently

■ Query output can be routed to disk, CRT report formatter,VISICALC1" or SOURCE7"

DATABASE MAINTENANCE—

■ Uses sophisticated screen formatting & data entry, likeon IBM 3270's!

■ Generates it's own screens automatically!

■ Handles records up to 4K in length, using multiplescreen "Pages"!

■ Automatic data compression for increased disk capacity

■ Uses SuperKram access method for incredibly fast access,LESS THAN .2 SECONDS FOR A RECORD!

■ Automatic index creation/maintenance

■ Automatic maintenance capabilities

■ "Goof-Proof" error handling

■ Input can come from VISICALC1" or SOURCE1"

DATABASE REPORTING—

■ Automatic headlines

■ Automatic field editing

■ Report fields can be calculated, sub-totaled & cross-footed in any manner desired

■ Optional counter breaks may be set

■ Automatic grand totals

■ Automatic statistics

REQUIREMENTS —

SuperKram (available separately) and: Commodore Pet 32K(40 or 80 col.) and 2040/4040/8050 disk OR Apple II 48K withApplesoft or language system and 2 disk drives orCORVUS.

ONLY $225

= Sfli ,= UNITED

£b SOFTWAREOF

750 THIRD AVE. AMERICA

Look lor the RED-WHITE-BLUEUnited Software Display at your localcomputer dealer, or send check ormoneyorder. plus S3.00 shipping

•

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NEW YORK NY 10017

(212) 682-0347 Telex 640055

*************

The resulting output is five projections of the logo withinthe 8V2-inch by 11-inch area. The four corner projections areof various sizes, all undistorted. The center projection isdistorted from that of the original sketch (see figure 5).

To understand the significance of the VIEWP parametersentered, the consequence of defaulting the SETAR subroutinemust be considered. Not calling SETAR defaults the viewportto the area delimited by LIMIT (the 215-mm by 280-mmviewgraph area). Because the viewport is a rectangle cor-responding to the viewgraph area, it has an AR of 0.768(215/280 = 0.768). For the purpose of determining the ver-tical parameters for viewport positioning, therefore, theheight of the viewgraph corresponds to 131 units. (Referringto the explanation of VIEWP: if AR is less than 1, then thevertical view surface is 100/AR units, or in this case100/.768 = 131 units).

In like manner, the width of the viewgraph corresponds to100 units. (If AR is less than 1, the horizontal length cor-responds to 100 units.) It is of little consequence to calculateparameters for positioning desired viewports. But if un-distorted projections are desired, the viewports must be de-fined with an AR equal to that of the window (2.73). Subse-quently, the corner viewports (calculated with an AR of 2.73)generate undistorted projections, while the center viewportcalculated with an aspect ratio of 0.79 generates a distortedprojection.

Summary

This article is not designed to make you a graphics expert.You still may not know a logical view surface from an il-logical one, and normalized device coordinates may notstrike you as normal at all. But your perspective on thegraphics process should now be broad enough to let youtackle more detailed technical explanations without losingsight of the basics. ■

Figure 5: Confined to an SVi-inch by 11-inch (215 mm by280 mm) viewing surface, the logo has been projected in 5 dif-ferent locations and sizes. The 4 corner locations appear un-distorted (the aspect ratios of the viewport and the window arethe same), while the central figure is distorted (aspect ratios ofviewport and window are unequal).

HOW MUCH MONEYDID VOU PLAN ON-SPENDING? YOU WANTCOLOR;OR Hi.RES. GRAPHICSOR &H CHARACTERS WIDEOR «fK,9k, I6KOR MORE/

KOR WITH A PRINTER ORA DISK}WJ£N DUAL DISKS?3 BIT OR 16 SIT?AND AMODEM, Do YOU LIKE80*0, -z-SO, 65QZ, I 802.

OR 68CO? AND ALSO A

GEE! I'LL NEED ACOMPUTER OUST TOHELP FIGURE OUTWHICH COMPUTERTO GET.

WELL FORTHAT \JjeHAVE...

T^r\S>LAK>

300 October 1981 © BYTE Publications Inc

Starting Today BIZCOMP Takes Overas the Price/Performance Leader

We all know about the old fashioned acoustic coupler. Ask any computer hot-shot. Finicky,prone to room noise, vibration. A mechanical weak-link in your otherwise all-electronic system.RELIABILITY is the key to no-hassle computing. And everybody knows you don't get reliabilitywith mechanical system components. So go ask that computer hot-shot—they'll tell youBIZCOMP's VersaModem all-electronic modem provides the new wave in personal communi-cations. A fully FCC certified direct connection to the telephone network. Exciting? You bet!

Not only can you access The Source, MicroNet, Dow-Jones, Computer Bulletin Boards andUniversity computers—the VersaModem offers access to a variety of specialized onlinedatabanks and timesharing services. The VersaModem is simple to install and operate. Andit's compatible with standard data terminals and a host of personal computers.

Before you buy a computer modem, look at BIZCOMP's versatility. Look at BIZCOMP's quality.With BIZCOMP's VersaModem you won't need another modem. If your local computer storedoesn't already have a VersaModem on display, ask them when they will!

BIZCOMP Communications...

Why not start with the best?

BIZCOMP

P.O. Box 7498 • Menlo Park, CA 94025 • 415/966-1545

Copyright ©1981 Business Computer CorporationCircle 44 on inquiry card.

Software Received

Apple

Clone Assembler, a 6502assembler and disk-based,line-oriented text editor forthe Apple II. Floppy disk,$39.95. Clone Software, 1446Estes St, Lakewood CO80215.

Meteoroids in Space, agraphics arcade game for theApple II and Apple II Plus.Floppy disk, $9.95. QualitySoftware, 660 Reseda Blvd,Suite 105, Reseda CA 91335.

Space Raiders, a graphicsarcade game for the Apple IIand Apple II Plus. Floppydisk, $29.95. United Softwareof America, 750 Third Ave,New York NY 10017.

Super Gomoku, a gamethat simulates checkers forthe Apple. Cassette, $9.95.United Software of America(see address above).

Super Stellar Trek, an

adventure game for the Ap-ple II. Floppy disk, $39.95.Rainbow Computing Inc,9719 Reseda Blvd, North-ridge CA 91324.

Universal Boot Initializer,a utility program for the Ap-ple II that will allow disks tobe booted from either DOS3.2 or 3.3. Floppy disk, $40.S H Software, POB 5, Man-vel ND 58256.

PET

Adventure at Pearl Har-bor, a submarine battle gamefor the Commodore PET.Cassette, $19.95. United Soft-ware of America, 750 ThirdAve, New York NY 10017.

Piano Player, a music-gen-eration program for the Com-modore PET. Cassette,$14.95. United Software of

FULL COLOR

GRAPHICS

The original 256-color imaging system withhigh resolution video FRAME GRABBERfor the S-100 bus. ^*s£h

Capture and digitize a video frame in 1/60 ofasecond. Select the best resolution for your „^application, from 256 to 1280 pixelsj J^?^;«')!'per TV line. Display your digitized #|£or computer processed image , ,"* f ,:with 256 gray levels or 256 (%;colors on standard u-^^v- ..ifBSW.MTSCorRGB \ , '

color TV

Compact two-boardbasic system

Sj'fl Features:

480x512 Computer-generated

I

i Highest possible quality 480x512x8 digital videoimage presently available on the market

> Input capability from TV camera or other sources

> Variety of synchronization choices

1 2 selectable vkleo A/D conversion circuits

> Choice of 1, 2, 4, 8, 16 or 32 bits per pixel

> 32K-byte Image memory on the basic system

> 32. 64, 128 & 2S6K byte system capacity

> Ughtpen input

> Photographic trigger control Input

> Software selectable system parameters

> Interfaces for TRS-80 and other processors

» Comprehensive line of accessories, monitors andsupport software

SEND FOR FREE CATALOG

= DIGITAL GRAPHIC SYSTEMS

= 935 Industrial Ave., Palo Alto, CA 94303

415/856-2500

America (see address above).

Space Intruders, a graphicsarcade game for the Com-modore PET. Cassette,$29.95. United Software ofAmerica (see address above).

Super Gomoku, a gamethat simulates checkers forthe PET. Cassette, $9.95.United Software of America(see address above).

TRS-80

Balloon Bust, a circus gamefor the TRS-80 Model I LevelII. Cassette, $15.95. Pro-gramma International, 3400Wilshire Blvd, Los AngelesCA 90010.

Blockade, graphics arcadegame for the TRS-80 ColorComputer. Cassette, $10;source list, $5. Bank Soft-ware, 37 Balmoral Dr, SpringValley NY 10977.

Breakout, graphics arcadegame for the TRS-80 ColorComputer. Cassette, $10;source listing, $5. Bank Soft-ware (see address above).

Runaway Racer, a car-racing simulation game forthe TRS-80 Model I Level II.Cassette, $15.95. ProgrammaInternational (see addressabove).

Space Colony, an arcadegame for the TRS-80 Model ILevel II. Cassette, $15.95.

Programma International(see address above).

Scrip-Fix, a patch for theScripsit word-processing sys-tem for the TRS-80 Model I.Cassette, $9.95. ProgrammaInternational (see addressabove).

Space Intruders, an arcadegame for the TRS-80 Model Iand III. Floppy disk, $19.95.Adventure International, POB3435, Longwood FL 32750.

Starship, graphics arcadegame for the TRS-80 ColorComputer. Cassette, $10;source listing, $5. Bank Soft-ware (see address above).

Super Gomoku, a gamethat simulates checkers forthe TRS-80. Cassette, $9.95.United Software of America,750 Third Ave, New YorkNY 10017.

ZX80

A Night in Las Vegas, a Las

Vegas gambling simulator forthe Sinclair ZX80. Cassette,$9.95. Lem Laboratories,POB 2382, La Jolla CA92038.

ZX80 Double Breakout, agraphics arcade game for theSinclair ZX80. Cassette,$14.95. Softsync Inc, POB480, Murray Hill Sta, NewYork NY 10156.■

This is a list of software packages that have been received byBYTE Publications during the past month. The list is correct to thebest of our knowledge, but it is not meant to be a full descriptionof the product or the forms in which the product is available. Inparticular, some packages may be sold for several machines or inboth cassette and floppy-disk format; the product listed here isthe version received by BYTE Publications.

This is an all-inclusive list that makes no comment on the qualityor usefulness of the software listed. We regret that we cannotreview every software package we receive. Instead, this list ismeant to be a monthly acknowledgment of these packages andthe companies that sent them. All software received is consideredto be on loan to BYTE and is returned to the manufacturer after aset period of time. Companies sending software packages shouldbe sure to include the list price of the packages and (where appro-priate) the alternate forms in which they are available.

302 October 1981 © BYTE Publications Inc

Circle 121 on inquiry card.

Circle 41 on inquiry card.

Ten reasons

I

BASF FlexyDiskNo.

lore than four decades of experi-ence in magnetic media—BASFinvented magnetic recordingtape, the forerunner of today'swide range of magnetic media,back in 1934, and was the firstindependent manufacturer ofIBM-compatible floppy disks.

Tough Tyvek sleeve —no paperdust, no static electricity.

Special self-cleaning jacket andliner help eliminate data errorsand media wear and tear.

BASF BASF FlexyDisk

Center hole diameter punched tomore accurate standards thanindustry specifications, for topperformance.

Bi-axially oriented polyestersubstrate - for uniform and reli-able performance year after year.

Cross-linked oxide coating-forlow head wear and long trouble-free media life.

Total capability—one of two man-ufacturers in the world thatmakes both 8" and 5.25" models,has tape and disk experience, andmanufactures floppy disk drives.

Double lubrication—lubricantsboth in the formula and on thedisk surface, to minimize mediawear due to head friction.

Packaging to suit yourrequirements — standard flip-topbox, Kassette 10® storage case,or bulk pack.

100% certification — every singledisk is tested at thresholds 2-3times higher than system require-ments, to be 100% error-free.

For the name of your nearestsupplier, write BASF Systems,Crosby Drive, Bedford,MA 01730, or call 617-271-4030.

BASF

Floppy Disks Mag Cards Cassettes Computer Tapes Disk Packs Computer Peripherals

Books Received

Active Filter Design Hand-book, G S Moschytz and PetrHorn. New York: John Wiley& Sons, 1981; 17.5 by 25 cm,316 pages, hardcover, ISBN0-471-27850-5, $45.

The Ada ProgrammingLanguage, I C Pyle. Engle-wood Cliffs NJ: Prentice-Hall, 1981; 17.5 by 23.5 cm,293 pages, softcover, ISBN0-13-003921-7, $14.95.

BASIC for Students: WithApplications, MichaelTrombetta. Reading MA:Addison-Wesley, 1981; 16 by23.5 cm, 291 pages, soft-cover, ISBN 0-201-07611-X,$9.95.

Build Program Technique:A Practical Approach for theDevelopment of AutomaticSoftware Generation Sys-tems, John G Rice. NewYork: John Wiley & Sons,1981; 15.5 by 23.5 cm, 372pages, hardcover, ISBN0-471-05278-7, $29.95.

CDS/ISIS and MINISIS: AFunctional Analysis andComparison, Robert LValantin. New York:UNIPUB, POB 433, MurrayHill Sta, 1981; 17.5 by 25 cm,88 pages, softcover, ISBN0-88936-296-3, $6.50.

Computer Acronyms, Ab-breviations, Etc, Claude PWrathall. Princeton NJ:Petrocelli Books, 1981; 15 by22 cm, 486 pages, hardcover,ISBN 089433-138-8, $17.50.Also available in softcoverfor $14.

Cryptography, A Primer,Alan G Konheim. New York:John Wiley & Sons, 1981;16.5 by 24 cm, 432 pages,hardcover, ISBN 0471-08132-9, $34.95.

Digital Counter Hand-book, Louis E Frenzel Jr. In-dianapolis IN: Howard WSams & Company, 1981; 13.5by 22 cm, 264 pages, soft-cover, ISBN 0-672-21758-9,$10.95.

Early British Computers,Simon Lavington. BedfordMA: Digital Press, 1980; 15

by 21 cm, 140 pages, soft-cover, ISBN 0-932376-08-8, $8.

Educational SoftwareDirectory, Apple II Edition,Sterling Swift PublishingCompany. Manchaca TX:Sterling Swift Publishing,1981; 15 by 22 cm, 103 pages,softcover, ISBN 0-88408-141-9, $11.95.

From ENIAC to UNIVAC,An Appraisal of the Eckert-Mauchly Computers, NancyStern. Bedford MA: DigitalPress, 1981; 19 by 24 cm, 286pages, hardcover, ISBN 0-932376-14-2, $21.

Fundamental Concepts ofInformation Modeling, MattFlavin. New York: YourdonPress, 1981; 15 by 23 cm, 128pages, softcover, ISBN 0-917072-22-7, $10.

How to Design & BuildYour Own Custom Robot,David L Heiserman. BlueRidge Summit PA: TabBooks, 1981; 13 by 21 cm,462 pages, softcover, ISBN0-8306-1341-2, $12.95; hard-cover, ISBN 0-8306-9629-6,$18.95.

How to Plan, Design andImplement a Bad System,Ronald B Smith. PrincetonNJ: Petrocelli Books Inc,1981; 14 by 22 cm, 157 pages,hardcover, ISBN 0-89433-148-5, $14.

Introduction to ComputerOrganization, Ivan Tomek.Rockville MD: ComputerScience Press, 1981; 16 by23.5 cm, 456 pages, hardcover,ISBN 0-914894-08-0, $21.95.

Linear Integrated Circuits,Practice and Applications, SolD Prensky and Arthur HSeidman. Reston VA: RestonPublishing Company, 1981; 16by 23.5 cm, 354 pages, hard-cover, ISBN 0-8359-4084-5,$21.95.

Microcomputer Architectureand Programming, John FWakerly. New York: JohnWiley & Sons, 1981; 17 by23.5 cm, 692 pages, hardcover,ISBN 0-471-05232-9, $27.95.

The Microelectronics Rev-

olution, edited by TomForester. Cambridge MA: MITPress, 1981; 15.5 by 23.5 cm,589 pages, softcover, ISBN0-262-56021-6, $12.50; hard-cover, ISBN 0-262-06075-2,$25.

The Minicomputer in On-Line Systems, Small Com-puters in Terminal-Based Sys-tems and Distributed Process-ing Networks, Martin Healyand David Hebditch. Cam-bridge MA: Winthrop Pub-lishers, 1981; 18.5 by 24 cm,334 pages, hardcover, ISBN0-87626-579-4, $22.95.

Osborne CP/M User Guide,Thorn Hogan. Berkeley CA:Osborne/McGraw-Hill, 1981;19 by 23.5 cm, 283 pages, soft-cover, ISBN 0-931988^4-6,$12.99.

Pascal Programming for theApple, T G Lewis. Reston VA:Reston Publishing, 1981; 15.5by 23 cm, 234 pages, soft-cover, ISBN 0-8359-54544,$12.95.

A Primer on Pascal, SecondEdition, Richard Conway,David Gries, and E CarlZimmerman. Cambridge MA:Winthrop Publishers, 1981;18.5 by 24.5 cm, 430 pages,hardcover, ISBN 0-87626-675-8, $17.95; softcover, ISBN0-87626- 671-5, $12.95.

The Programming LanguageLandscape, Henry Ledgard and

Michael Marcotty. Chicago IL:Science Research Associates,1981; 16.5 by 24.5 cm, 460pages, hardcover, ISBN 0-574-21340-6, $22.95.

Robot Intelligence with Ex-periments, David LHeiserman. Blue Ridge SummitPA: Tab Books, 1981; 13 by21 cm, 322 pages, softcoverISBN 0-8306-1191-6, $9.95;hardcover, ISBN 0-8306-9685-7, $16.95.

Software Design: Methodsand Techniques, Lawrence JPeters. New York: YourdonPress, 1981; 17.5 by 25.5 cm,248 pages, softcover, ISBN0-917072-19-7, $23.

Structured Programming inFORTRAN, Louis A Hill Jr.Englewood Cliffs NJ: Prentice-Hall, 1981; 17.5 by 23.5 cm,526 pages, softcover, ISBN0-13-854612-6, $15.95.

Take Aim: Volume I, JamesHoyt Clark. Beaverton OR:Matrix Publishers, 1981; 388pages, 22 by 28 cm, softcover,ISBN 0-916460-29-0, $16.95.

Video/Computers, How toSelect, Mix, and Operate Per-sonal Computers and HomeVideo Systems, Charles J Sippland Fred Dahl.EnglewoodCliffs NJ: Prentice-Hall,1981; 18.5 by 24 cm, 246pages, softcover, ISBN 0-13-941849-0, $7.95; hardcover,ISBN 0-13-941856-3, $15.95.■

This is a list of books received at BYTE Publications during thispast month. Although the list is not meant to be exhaustive, itspurpose is to acquaint BYTE readers with recently published titlesin computer science and related fields. We regret that we cannotreview or comment on all the books we receive; instead, this list ismeant to be a monthly acknowledgment of these books and thepublishers who sent them.

304

October 1981 © BYTE Publications Inc

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more effective programs. And, with ad-vanced programming skills, the techni-cian can test and debug systems quicklyand easily.

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NRI training is hands-on train-ing, with practical experiments anddemonstrations as the very foundationof your knowledge. You don't just pro-gram your computer, you go insideit.. .watch how circuits interact... inter-face with other systems.. .gain a realinsight into its nature.

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News and Speculation About Personal Computing

Conducted by Sol Llbes

J mart Credit Card Uses

EEPROM: SCS-ATES hasintroduced XCARD, an elec-tronic credit card that usesan EEPROM (electricallyerasable, programmableread-only memory) to keeptrack of your remainingcredit. The EEPROM is en-capsulated in a thin plasticcard. It's inserted into areader that accesses thedata in the 17-word by 8-bitEEPROM and subtracts theamount charged by writingto the EEPROM. Fifteenbytes are alterable; theothers are for identificationand security code (to checkfor fraudulent erasure). Pro-totypes are being tested inItaly.

B

Ug-Money Prizes InComputer Chess Battle:

Big money is waiting for thecomputer chess program de-veloper whose program de-feats a human chess expert.Omni magazine is offering$16,000 to the first programthat can beat David Levy,the Scottish National ChessChampion (Elo rating of2310). (Elo ratings are recog-nized by the World ChessFederation.) A Netherlandssoftware firm will award$50,000 to the developer ofthe first program that bestsMax Euwe (Elo rating of2540), and the Fredkin Foun-dation of Massachusetts willpay $100,000 to the programthat overpowers the stand-ing world chess champion(typical Elo rating of 2700).

Most experts feel theseprizes could be won withinthe next five years, and willcertainly be awarded withinthe next ten years. TheUnited States Chess Federa-

306 October 1981 © BYTE Publications Inc

tion has voted to permitcomputers to compete insanctioned matches with hu-man players. In 1983, therewill be a team-chess tourna-ment in which one team willbe entirely computers.

V

OS Gains In Popu-larity: Switching from onecomputer to another usuallymeans jumping from oneDOS (disk operating system)to another. Then, you haveto learn how to operate anentirely new system, whichoften means redevelopingexisting software so that itwill run. In a commercial en-vironment, this can be veryexpensive.

To overcome this prob-lem, researchers at theLawrence Berkeley Labora-tory, University of Califor-nia-Berkeley, have createda VOS (virtual-operating sys-tem) as an interface betweenthe DOS and the hardware.Called Software Tools, thesystem has already been im-plemented on several dozensystems ranging from IBM,DEC (Digital Equipment Cor-poration), Honeywell, andBurroughs mainframes tominicomputers and evenmicrocomputers usingDigital Research's CP/MDOS. Using a VOS, an organ-ization's software canoutlive its hardware, whichdoes away with costly soft-ware redevelopment.

The Software Tools VOSis supported by a user groupthat publishes a newsletter,directory, documentation,holds regular meetings, andmakes the Software Toolssoftware available on mag-netic media for $35. Formore information contact

Debbie Scherrer, LawrenceBerkeley Laboratory, CSAM-50B/3209, University of Cali-fornia, Berkeley CA 94720.

#mnglo-French Video-text Standard: British andFrench negotiators haveagreed on a common video-text/teletext standard thatmakes Britain's Prestel andFrance's Antiope systemscompatible. Canada alsomay adopt the standard,which could affect Ameri-can videotext systems.

R.

LObotlcs Update: Stan-dard & Poor's predicts thatrobotic sales in this countrywill leap from less than $100million to nearly $1 billionby the end of the decade. (Asan aside, Japan already usesmore than three times asmany robots as the US.)General Electric has dis-closed that it will replace15,000 workers with 8000robots during the next fiveyears; and that if it cannotdo this, it will not be able tocompete economically.

Industrial robots currentlycost in the $7500 to $250,000range (with one specializedunit selling for $2.5 million).The average price is around$40,000, which is expectedto fall to $10,000 by 1983 ascompanies such as IBM andTexas Instruments are ex-pected to enter the market.

Robots are projected tocost between $1.75 to $4.75an hour, compared to the$12 to $15 per hour wagespaid for skilled labor. Theirgreatest impact has been inthe automobile, steel, andaerospace industries. DrRichard John, Director ofthe Office of Energy and En-vironment, of the Transpor-

tation System Center, Cam-bridge, Massachusetts, haspredicted that by 1985 auto-mation will replace morethan 200,000 workers in theauto industry.

The Fujitsu Francu robotfactory, in Japan, reportsthat it operates 16 hours aday entirely by robots. Hu-man workers come in foreight hours to complete thefinal assembly of the ma-chines and robots. Fujitsufeels that it will have theplant completely robotizedby 1985. Hitachi claims tohave 500 scientists and en-gineers working on thedevelopment of a new gen-eration of robots that will beable to "see, feel, and walkup aVid down the factoryfloor supervising otherrobots."

Microbot Inc of MenloPark, California, has had its$1700 robotic arm, used witha Radio Shack TRS-80, onthe market for over a year.Thus far, 40 have been sold.Terrapin Inc has sold 150 ofits Turtles, which can run amaze or draw pictures. Butmost of these units havegone into schools, not thehome.

The problem is that thecost of a robot that will domeaningful tasks is still veryhigh. Although low-cost sen-sors and mechanical com-ponents are available, ahuge amount of expensiveelectronic processing is re-quired. A general-purposerobot requires a multipro-cessing, multitasking com-puter system, with a highdegree of artificial in-telligence so that the robotcan sense its environmentand respond properly withina reasonable time. More ad-vances in artificial-intelli-gence programming tech-niques are still needed.

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Most experts agree thatrobots will move into thehome just as computershave done —but this is stillat least five years andmaybe as much as 20 yearsaway. We will probably seethe first "home robots" per-forming only specific orlimited sets of tasks. Mostlikely the first applicationswill be robotic aids for thehandicapped. For example,Stanford University hasmodified an industrialrobotic arm for use by quad-riplegics. It recognizes voicecommands, repeats them forverification, then acts ac-cordingly. Also, it can pickup a telephone, fetch abook, turn pages, pourdrinks, or hold a glass. TheVeterans Administration iscurrently testing the unit.

Experimenters interestedin building a robot shouldnote that Hobby RoboticsCompany, POB 997, LilburnGA 30247, has announced amobile unit that consists of abody and two arm manipula-tors. It costs $1495. The usermust supply the electronics.Hobby Robotics also pub-lishes a quarterly newsletter.

Heathkit will jump intothe robotics market nextyear with an under-$1000robot kit. It will be mobileand will have a seven-motormanipulator, sonar-type sen-sor, a Motorola 6809-basedcontroller, and an "ex-perimenter's area" whereusers can wire circuits. Therewill be several modes ofoperation, including auto-matic and teach/learnmodes. It will be primarilyan educational tool,teaching modern industrial-control techniques.

N.

I ew Scheme To HaltSoftware Piracy: To copewith software pirates, sup-pliers have used nonstan-dard data formats, slashedtheir prices low, or tried to

ignore the problem. Somehave printed their documen-tation in light blue ink toprevent photocopying.

But this resulted in acatch-22: the suppliers whouse nonstandard formatshave been severely criti-cized by purchasers whocannot make backup copiesand must return the disk tothe supplier if it is damaged.This is a real annoyance and,if the supplier charges forthis service, engenders re-sentment. Format-indepen-dent programs that copy thedisk bit by bit are availableby popular demand.

Now, at long last, Micro-Technology Unlimited,Raleigh, North Carolina, andHal Chamberlin, creator ofmany innovative microcom-puter features, have im-plemented a previouslytalked about method for pre-venting piracy: a software-readable serial number em-bedded in hardware. Here'show it works: the supplier in-tegrates the code in the soft-ware when it is ordered.When the program runs, thetwo serial numbers are com-pared; if they do not match,the program doesn't run.Thus, users can make anynumber of copies and in-tegrate a program with othersoftware to form a newpackage.

I suspect that the serialnumber is embedded in aROM (read-only memory)that uses an algorithmknown only to the hardwaremanufacturer and licensedsoftware vendors. It may usea PLA (programmable-logicarray), which cannot beduplicated as simply as aROM. Also, the software-checking routine has to bedone in a clever and subtleway so that it cannot be easi-ly located and bypassed.

V,

Irtual Memory ForMicrocomputers: Early

next year, Intel, Zilog, Moto-rola, and National Semicon-ductor will introduce in-tegrated circuits to addVMM (virtual-memory man-agement) to 16-bit micropro-cessors. This will givesystems the large-capacitystorage previously found on-ly in large mainframes.

VMM creates a more effi-cient integration of the pri-mary small (but fast) semi-conductor main memoryand the secondary (slow)large disk storage. It freesthe programmer from wor-rying about the details ofstorage allocation. Also, itmore efficiently managesthe use of memory and diskstorage when many usersshare memory.

Zilog, Motorola, and Na-tional Semiconductor alsowill introduce separateMMU (memory-manage-ment unit) integrated cir-cuits to work with their16-bit microprocessors. Intelwill unveil a new version ofits 16-bit microprocessorthat will include an MMUcircuit. The Zilog MMU willmanage an 8-megabytememory space compared tothe others' 16-megabytes.

Juper-Graphlcs: NipponElectric Company (NEC) isabout to go into productionon a new graphics-controllerintegrated-circuit chip thatwill make super-color graph-ics possible on microcom-puters. Listen to these speci-fications: displays 2048 by2048 pixels (picture ele-ments) in the black-and-white mode or 1024 by 1024pixels in the color mode;generates all timing and syn-chronization signals; allowsboth graphics and text onthe same screen; supports upto 64 K (16-bit word) dis-play memory; contains hard-ware for drawing lines, arcs,circles, rectangles, and char-

acters at 800 ns per pixel;supports two display areas(independently pannable);has an auto-advance cursor;will display 256 charactersper row and up to 100 rowsper screen; will zoom dis-play to sixteenfold; has alight-pen input; 8-bit inter-face for microcomputers;and DMA (direct-memoryaccess) capability ... all inone 40-pin package.Samples should becomeavailable next month withproduction quantities ob-tainable early next year.Single-quantity price is ex-pected to be $150.

I o Be A 128 K-BIt OrA 256 K-BIt ROM—ThatIs The Question: Althoughfive integrated-circuit manu-facturers are providingsamples of the new 128 K-bit, or 16 K-byte, ROM(read-only memory), othershave opted to skip the thatsize and go directly to 256 Kbits (32 K bytes), notablyMotorola. These large-sizedROMs are expected to beused mostly in high-levellanguage processors, intel-ligent typewriters, smart ter-minals, language translators,and speech-synthesis sys-tems. You can expect to see128 K-bit ROMs on the mar-ket by year's end and the256 K-bit ROMs by mid-1982.

^mpple Computer Reg-isters Stock Offering: Ap-ple Computer Inc has regis-tered a proposed publicstock offering of 2Va millionshares at $27.50 each. (Itsoriginal offering last yearwas 5 million shares at $22each, although this rose $7minutes after going on sale.)Also, the president and vicechairman of Apple (A CMarkkula and Michael MScott) have granted the un-derwriters options to pur-

308 October 1981 © BYTE Publications Inc

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chase up to 125,000 of theirpersonal shares, reducingMarkkula's and Scott's re-spective holdings to 12.5%and 4.9%. Xerox has pulledback its interest from 720,000shares to 470,000 shares.

Apple spent $9.1 millionon research and develop-ment in the first half of 1981,compared with $7.3 millionfor all of 1980. It also claimsto have shipped more than4000 Apple 11 Is by the end ofApril.

■ CC Revises Interfer-ence Rules: The FederalCommunications Commis-sion (FCC) has revised itsrules regarding the certifica-tion of small computers forradio-frequency interference(RFI). The revision clarifiesthe definition for exempt de-vices: self-contained deviceswith clock frequencies of495 kHz or less are now ex-empt from certification.However, virtually all micro-computers presently soldhave higher clock rates andare not exempt.

If your television set isbothered by RFI from yourpersonal computer, citizen'sband radio, etc, you may beinterested in obtaining a freebooklet entitled "How toIdentify and Resolve Radio-TV Interference Problems."It is published and distri-buted by the FCC.

B,

'ASIC Standards Man-ual Published: The Gov-ernment Printing Office haspublished a two-volumestandard on the BASIC lan-guage. The stanadard isbased on the ANSI (Amer-ican National Standards In-stitute) minimum criteria forthe language. The 556-pagedocument describes test pro-grams to check if a BASIC im-plementation complies withthe Federal Information Pro-cessing Standard 68 and

ANSI standard X3.60-1978.

Volumes 1 and 2 cost $4and $9.50, respectively.Order them from the Super-intendent of Documents, USGovernment Printing Office,Washington DC 20402. Theorder numbers are 003-003-02262-4 (Volume 1) and003-003-02263-2 (Volume 2).

Werox 820 PersonalComputer: Xerox has intro-duced a desk-top personalcomputer, called the Xerox820. It costs $2995. Itsoriginal internal code namewas WORM, which stood forWonderful Office Revolu-tionary Machine.

The Xerox 820 uses theZ80 microprocessor, has64 K bytes of memory, twosingle-sided single-density5-inch floppy-disk drives,and two serial and twoparallel ports. A Diablo 630printer is available foranother $2900, and an 8-inchfloppy-disk (250 K-byte)drive is $800.

The 820 uses the CP/Moperating system (a de factomicrocomputer standard),with certain limitations (e.g.,CP/M's powerful input/out-put byte feature is not im-plemented). But, it is asignificant boost for theCP/M-software market. Also,Xerox will offer MicrosoftBASIC, CBASIC-II, COBOL-80, and several currentlyavailable CP/M-based soft-ware packages.

Xerox will furnish its ownversion of the popular Word-Star word-processing soft-ware package. Most of itschanges are in redefining theControl sequence func-tions—which undoubtedlywill confuse users who arerunning the package onother systems.

The video display ismemory-mapped and shareslow-memory space via abank I/O (input/output) port-

select scheme; the disk con-troller uses the popular 1771integrated circuit. Resetcauses a jump to a ROM(read-only memory) in highmemory from which the usermust boot CP/M, which doesnot start automatically. AZilog SIO (serial I/O) in-tegrated circuit is used tohandle I/O operations. Al-though Xerox implies thatthe 820 can be used as aworkstation in an Ethernetnetwork, no internal Ether-net interface is provided atthis time.

On the minus side, theXerox machine has two Con-trol keys, both positionedadjacent to the space bar(they may be easy to hit ac-cidentally). Also, I wonderwhy Xerox used drives withonly 92 K bytes storage perdrive, when virtually every-one else has gone to double-sided or double-densitydrives with two or four timesthe storage capacity. Both HP(Hewlett-Packard) and IBMhave introduced Z80-basedpersonal computers; DEC(Digital Equipment Corpora-tion) may follow suit. Fur-ther, Xerox will have to com-pete with several dozenmachines with equal or bet-ter specifications, some ofwhich are less expensive andhave been available for aslong as three years.

On the plus side, Xeroxknows that its name can sella lot of machines, and it hasalready signed up severallarge distribution organiza-tions, such as Computer-land. It is interesting to notethat Xerox's 17 retail storeshave been selling Applecomputers, I wonderwhether this, too, will con-tinue?

R,

landom News Bits:

Apple Computer is offering afree resource guide on usingmicrocomputers as aids forthe handicapped. It sum-

marizes work being done inthe field and current pro-jects. It includes a biblio-graphy and where to go forhelp and advice. For a copyof "Personal Computers forthe Physically Disabled: AResource Guide," write toApple Computer, ResourceGuide, Marketing ServicesDepartment, 10260 BandleyDr, Cupertino CA 95014. . . .The People's Republic ofChina will soon conduct itsfirst national census. The USCommerce Department hassent the Chinese a computerand some US Census Bureauexperts to help. The last cen-sus was done using theabacus . . . CompuServe Inc,one of the largest time-sharing systems for home-computer users, claims tohave 10,000 customers, con-centrated mostly aroundNew York City, the easternseaboard, the Silicon Valleyarea, and Los Angeles. . . .Attendance at last April'sSan Francisco ComputerFaire rose to almost 32,000.That's a jump of 12,000 overthe year before. . . . TheStrafford, Pennsylvania,Public Library has installed acoin-operated TRS-80. Thelibrary committee hadhoped that students woulduse the computer for home-work, but instead mostplayed games. At fifty centsfor 15 minutes, a user canaccess any one of 24 pro-grams, including one thatteaches BASIC. The machinewas installed and operatedby the same company thatsupplies the library's photo-copier. . . . The Mount SinaiSchool of Medicine in NewYork City will conduct an in-vestigation for the News-paper Guild into possiblehealth problems associatedwith the use of video-displayterminals. . . . "Go public,young firm!" seems to be thecry since Apple tried it lastDecember. Later this year,Vector Graphic, Intertec

310 October 1981 © BYTE Publications lnc

e Board System

Z80A 4Mhz CPU and chip family (optional 6Mhz system)

• Floppy disk controller which supports 51/» and 8 inch drivessimultaneously (total 4)

• DMA for the floppy disk drives

• 2 parallel and 2 serial communication ports

• Bus expander from the CPU with 256 I/O ports

• 64 K bank select low power RAMHard disk support (up to 4 drives of mixed sizes)

• Tape back up support

• Supports both serial and parallel printers$1295

jf ■ if?"

.. ■ - ■. *

Qume Datatrak 8

$545

Includes 1 year factory warranty

Qume Datatrak 5

$315

Includes 1 year factory warranty

Qume Sprint 9/45

$2295

Light Pen

with cord and socket$75

Teletek FDC 1

4Mhz CPU

NEC 765 disk controller$605

1 year warranty

IMMEDIATE DELIVERYQUANTITY DISCOUNTS

Interlink Modem

• 300-600 baud

• Asyn/Syn

• Auto Dial

• Auto Answer

• Serial and modular jackinterface

• 2 year warranty

$119

Floppy DiskAdd-Ons

• Dual double density drives

• Enclosure

• Power supply and fan

• All cables

• 1 year warranty

8" system $137551/4" system $949

Circle 294 on inquiry card.

Circle 177 on inquiry card.

PRODUCTS

COMPLETE CATALOG OF COMPUTEREQUIPMENT AT DISCOUNT PRICES.

ANOTHER BOMBSHELLFROM INNOVATIVE PRODUCTS!

S299

64K-4Mhz.-IEEEAssembled & Tested

64K S-100 DYNAMIC RAM MEMORY

BY COMPUTER SYSTEM RESOURCES

Works with Cromemco, North Star, Teletek, Tarbell, most Z80 and8080 systems even with DMA

Guaranteed to work in your system or your money will berefunded within 15 days of purchase

ALSO AVAILABLE PARTLY POPULATED:

16K $239.00 32K $259.00

48K $279.00

Q.T. COMPUTER SYSTEMS:

MODEL DESCRIPTION lALl ARSFMBLI D & TFSTEDI PRICE

MF * DD12A ... 25 A Mainlrame: 12 Slot. S100. Dual 8" Drive . $625 00

MR18A 25 A Tabletop Mainlrame: 18 Slot. S100 450 00

MR 12A 25 A Mainframe: 12 Slot. S100. Dual 5" Drive .. 450 00

Z+80A Single Board. Z-80 Computer 2/4 Mhz .S-100 .. 185.00

Z*80A/22 Monitor Program for Z<80A & Tarbell or VF-1.... 30.00

RAM 32 32K Static RAM Board. Low Power. S-100 499 00

QTCIOA 2 Serial &4 Parallel Port I/O. S-100 339 00

QTCCCSA Clock Calendar Board. S-100 125.00

OTCCCAA Clock Calendar Board, lor Apple 125 00

OTCCCTRS80 Clock Calendar Module lor TRS-80 125 00

VISTA COMPUTER COMPANY:

MODEL DESCRIPTION ALL ASSFMBLfD & TESTEDl PRICE

V300/25 .. Letter Quality Printer. 25 CPS S189500

V300/45 ..Letter Quality Printer. 45 CPS 2195 00

V-DRIVE .. Dual 8" Disk Cabinet. Power Supply. Rack Mountable ... 375 00

COMPUTER SYSTEM RESOURCES:

MODEL DESCRIPTION (ALL ASSFMBLID & TFSTEDi ... .■ PRICE

RAM 16...16K Static RAM, S-100 $179.00

RAM I6C . Low Power (CMOS) Version of RAM 16. 1 3 Watt.... 259.00

RAM 65... 16K Static RAM. I/O Port Bank Select. S-100 189.00

RAM 65C .Low Power (CMOS) Version ol RAM 65. 1 4 Watt ... 279 00RAM 32 .. .32K Low Power 8 Bit Static RAM, 24 Address Lines. 499,00

RAM 256..256K 8/16 Bit Dynamic RAM, Fully IEEE 696 1295.00

I/0-8 8 Port Serial I/O, Fully IEEE, up to 200K BAUD 395 00

ORDERING INFORMATION:

Minimum Order is $15.00. Prices quoted do not include shippingand handling. Foreign orders require prepayment by MICR orMoney Order in U.S. funds. Purchase Orders accepted from US.Government & firms with published A1 Rating from Dunn &Bradstreet. All other orders require prepayment, charge card.or COD shipment.

TOLL-FREE PHONE NUMBER:

Call Toll-Free: 1 (800) 423-5141, In Alaska, California, andHawaii, call us collect at (213) 883-3244.

TO RECIEVE OUR FREE CATALOG:

Call our Toll-Free (800) number, or circle Reader Service tf.

7131 OWENSMOUTH AVE. / >CANOGA PARK, CALIFORNIA 91303213 / 883-3244800 / 423-5141

BYTELINES

Data Systems, and Com-puter Factory Inc will followApple's lead. . . . New WorldComputer Company, CostaMesa, California, has a novelway to provide Winchesterhard-disk backup. Its new5-inch floppy-disk driveshave both fixed storage anda removable cartridge. NewWorld has a drive with4 megabytes fixed and4 megabytes removable. Itcosts less than $1200. . . .Micropolis Corporation willsoon start shipping 5-inchfloppy-disk drives with 2.2megabytes formatted stor-age. . . . Apple will soon of-fer a videotext interface thatwill allow the Apple II andIII computers to accessCanada's Telidon system.AT&T has also decided tomake its videotext Telidon-compatible. These systemscan deliver computerizeddata to your home via eithercable television, telephonelines, FM subcarrier, orunused television scan lines.Observers expect future en-hancements of videotext toprovide message/teleconfer-encing, picture manipula-tion/animation, and down-loading of data files fromlarge systems to personalcomputers. . . .

I?

andom Rumors:Word is that HP's (Hewlett-Packard's) personal-comput-er operations recently splitoff from the small-computerdivision and is now a sepa-rate entity. HP will soon in-troduce a multicolor plotterfor its Series 80 personalcomputers. . . . Cromemco,one of the leaders in S-100Z80-based systems, is ex-pected to release a 68000-based 16-bit processor cardthat includes a Z80 copro-cessor. Rumor is that Cro-memco has been working onthe card for almost twoyears. . . . Expect CodboutElectronics to introduce

68000 and 8086 S-100 cardsbefore year's end. . . . It'srumored that DEC (DigitalEquipment Corporation) isabout to release a personalcomputer, as HP has alreadydone. HP's system is calledthe HP-125 and uses a Z80.DEC's desk-top unit willprobably contain a Win-chester hard-disk drive andeither an LSI-11 or a stan-dard processor like the Z80.DEC is already using Micro-soft BASIC in its CIGIgraphics terminal. . . .

I RS-80 Meets IBM:

Radio Shack has three newsoftware packages thatallow various forms of com-munication between theTRS-80 Model II and IBMmainframe equipment. Thefirst is Reformatter. It con-verts data on Model IITRSDOS 5-inch floppy disksto the standard IBM format(3741 single-density). Thismeans that Model lis cannow be used for off-line dataentry in businesses whereSystem 360/370 or other3741-compatible equipmentis employed. The other pro-grams allow "bisync"(binary synchronous) com-munications by emulatingthe IBM 3270 and 3780. TheModel Ms serve as onlineand remote job-entry ter-minals for IBM 3270- and3780-compatible equipment.Reformatter sells for $249;the bisync packages sell for$995 each, which includesinstallation by Radio Shack.

MAIL: I receive a largenumber of letters each monthas a result of this column. If youwrite to me and wish aresponse, please include a self-addressed stamped envelope.

Sol LibesPOB 1192Mountainside NJ 07081

312 October 1981 © BYTE Publications Inc

M.T.I.MOD IIIPLUS

Now You ConSave $500 overcomparable models.

* We have token rhe basic 16K Model III expanded rhememory ro 48K and added our MTI Double DensityDual Disk Drive system. Our system is fully compatiblewith Radio Shack DOS and peripherals.

M998

•SAVE $500. OVERMODELS WITH COMP,SPECIFICATIONS.

MOD IN/EXPANDED

Same as above bur has double srorage capacity(706 srorage). Your choice of 2 dual headed 40rtack drives or 2 single headed 80 track disk drives.

$2499

MOD Ml/280

Our lorgesr MOD III, approximately 1.5 mega bytesof storage, utilizes 2 dual headed 80 track, doubledensity disk drives. Complete with manuals andprofessional operoring sysrem. Microsystems DOSplus 3.0.

J2799

MICROCOMPUTERTECHNOLOGY INC.

3304 W. MACAPJHUR,

SANTA ANA, CA 92704

• (714) 979-9923 •

..

■

r '\ ^MasterCard

L W i

~^^T^^r

U.S. PRICESFOB SANTA ANACALIFORNIA

DEALER INQUIRIES INVITED

MTI MOD III SALES,

PARTS & SERVICE CENTERS

-INDEPENDENTS DEALERS

SAN JOSE. CA 408 946-1265

SANTA CRUZ. CA 408 427-0836

LANCASTER. CA 805 942-5747

HOLTVILLE. CA 714 356-5185

OXNARD. CA 805 486-5837

SAN DIEGO, CA 714 275-4243

TEMPE. AZ 602 839-0546

PHOENIX, AZ 602 244-9739

TUCSON, AZ 602 323-9391

SIERRA VISTA, AZ 602 458-2479

DENVER, CO 303 696-0777

CHEYENNE, NVY 307 632-9132

TEXAS 214 247-6679

N. & S. DAKOTA 701 594-5674

MIDWEST 616 345-5068

JOPLIN. MO 417 781-1748

CLEVELAND, OH 216 779-6040

MAUMEE. OH 419 893-4288

GEORGIA 404 449-8982

FLORIDA 305 980-9191

TROY. NY 516 273-6411

GROTON, Q 203 445-5166

OVERSEAS

REP. OF SOUTH AFRICA 021-45-1047

AUSTRALIA 03-877-6946

Circle 231 on inquiry card.

No risk Disk Drives

ASAP carries only the highestquality floppy disk drives, toprovide you with years of trouble-free service and superiorperformance.

Data Trak™ double-sided double-density drives from Qume® featurestate-of-the-art technology. Youget superior data integrity throughimproved disk life, data reliabilityand drive serviceability.

Data Trak™ 5 (ANSI 5W compat-ibility) Call for price

Data Trak™ 8 (IBM compat-ibility) Call for price

Shugart drives have been settingindustry quality and reliabilitystandards for years. Shugart'sBi-Compliant™ head assemblyprovides superior media com-pliance and high reliability.Model 801

(standard floppy) $425.00

Model 850 $640.00

Dual Disk Drive Cabinet .. $265.00

ASAP also provides a full line ofhigh reliability disk drivesubsystems.

Part No. — Description* PriceDDC+8 sgl — Cabinet for single8" floppy disk drive... $ 185.00

DDC+8-1 - Cabinet with (1)Shugart SA801R

installed $ 595.00

DDC+8-2 —Cabinet with (1)Qume® DT-8 double-sideddouble-density drive

installed $ 695.00

DDC+88-3 — Cabinet for dual 8"floppy disk drives ....$ 275.00C0MB0-8 — Dual cabinet for 8"floppy disk drives (horizontalmounting) $ 265.00

C0MB0-9 - Cabinet for 8"floppy disk drives (vertical

mounting) $ 265.00

C0MB0-8/9+1S — Dual cabinetwith (1) Shugart SA801Rinstalled (horizontal or vertical

mounting) $ 725.00

C0MB0-8/9+2S — Dual cabinetwith (2) Shugart SA801R'sinstalled (horizontal or vertical

mounting) $1150.00

C0MB0-8/9+1Q — Dual cabinetwith (1) Qume® DT-8 double-sided double-density driveinstalled (horizontal or vertical

mounting) $ 865.00

C0MB0-8/9+2Q — Dual cabinetwith (2) Qume® DT-8's double-sided double-density driveinstalled (horizontal or verticalmounting) $1385.00

X5 —Cabinetfordesktop main-frame (small power

supply) $ 200.00

800D — Cabinet for desk topmainframe (standard powersupply) $ 255.00

'All cabinets come complete with powersupply. Ian and internal cables.

For superior quality, high reliability diskdrives, contact ASAP today.

SDSYSTEMS/S-100 BOARDS

EXPANDORAM 16K $240.00

2 MHz DYNAMIC 32K S258.00

RAM BOARD 48K $276.00

KITS 64K S294.00

EXPANDORAM II 16K S250.00

4 MHz DYNAMIC 32K S268.00

DAM BOARD 48K S286.00

KITS 64K S304.00

SBC-100 KIT 2.5 MHz/Z80 CPU with Serial I/OPorts & SBC 100 Monitor of your choice atno charge $299.00

SBC-200 KIT 4 MHz/ZSOA CPU with Serial 8,Parallel I/O Ports & SBC 200 Monitor of yourchoice at no charge S325.00

VERSAFLOPPY I KIT Disk Controller for 5W or 8"Drives, Single or Double Sided/Single or DoubleDensity. S-100 Compatible J250.00

VERSAFLOPPY II KIT Disk Controller for 5V4" or 8"Drives. Single or Douole Sided/Single or DoubleDensity. S-100 Compatible S300.00

PROM 100 KIT S-100/EPROM PROGRAMMER for2708. 2716, 2732 & (Tl) 2516 S190.00

ALL BOARDS ARE AVAILABLE ASSEMBLED &TESTED, CALL FOR PRICES

DISKETTES from ASAPVERBATIM

5"<" DISKETTES

SectoringSoftHard 10Hard 168" DISKETTESHardSoft

MEM0REX

PA" DISKETTESSides/Density Sectoring

1/Single Solt1/Single Hard 101/Single Hard 16

8" DISKETTESSides/Density SectoringMEM 3060 1/Single SoltMEM 3101 2/Single SoftMEM 3090 1/Double SoftMEM 3102 2/Double Soft

DYSAN

B'A" DISKETTESPart # Sides/Densily SectoringD-0130 1/Single Soft

D-0226 1/Double Soft

D-0235 2/Double Soft

8" DISKETTES

Pari #

MD525-01MD525-10MD525-16

F032-1000

FD34-1000

Part*MEM 3401MEM 3403MEM 3405

Part #

Part*

D-0506

D-0605

Part/f

744-0

744-10

744-16

745-0

745-10

745-16

Pari #

MD1MD2DMH1MH2D

Part*

FD1-128FH1-32FD2-XD

Part #

SRW-5SRW-8

Sides/Density Sectoring

1/Single Sofl2/Double Soft

SCOTCH 3M

5'." DISKETTES

Sides/Densily

1/Single1/Single1/Single2/Double2/Double2/Double

Sectoring

SoflHard 10Hard 16SoftHard 10Hard 16

MAXELL

5V DISKETTESSides/Densily Sectoring1/Single Soft2/Double Soft1/Single Hard 162/Double Hard 16

8" DISKETTESSides/Densily Sectoring

1/Single Solt1/Single Solt 322/Double Sofl

SRW

MEDIA STORAGE CASESSize

5'V

Price

10/S27 5010/S29.5010/S29.50

10/S35.0010/S35.00

Price

10/S250010/S250010/S25.00

Price

10/S35.0010/S45 0010/S45.0010/S5500

Price

10/S45.0010/S460010/S5500

Price10/S45.0010/S6500

Price

10/S33.0010/S33 0010/S33.0010/S59.0010/S590010/S59.00

Price10/S39 0010/S650010/S39 0010/S6500

Price

10/S45.0010/S450010/S65.00

PriceS2.50 eaS3 25 ea

asait

computer ■products, inc.

314

BYTE October 1981

Circle 31 on Inquiry card.

ATARI 800

(16K) Personal BusinessComputer Features:

• Computer console

• Atari 8K basic

• 57 full stroke alpha-numeric keyboardwith four functionkeys

• Operator's manual

• RF modulator

• Power supplyPrice: $799.00

Atari Optional Accessories

Model # Description Price

810 Disk Drive System S 455.00815 Disk Drive System $1195.00820 40 Column Dot

Matrix Printer $ 279.00

822 40 Column Thermal

Printer S 349.00

825 80 Column Dot

Matrix Printer S 625.00

830 Acoustic Modem .. .$ 159.00

850 Interface Module .. .$ 139.00

410 Cassette Recorder $ 60.00

CX30-04 Paddle Controls.... S 17.95

CX40-04 Joysticks (pair) ....$ 17.95

INTRODUCING ASAP's

Atari 800 16K RAM Module $75.00

1 year warranty parts & labor

Special Offer: Additional 16K RAM FREE with purchase of system.

MICROBYTE Z-80A/l-O CPU BOARD

• A complete single board Z80A CPU withserial/parallel interface

• Fully compatible with the proposed IEEE S-100 8ns Standard

• Z80A CPU (4MHz version of the Z80)

• 158 instructions — superset ot and upwardcompatible from the 8080s 78 instructions

• Up to 4K of on board Eprom with optionalZ80 monitor program — 1KI2708). 2KI2716)or 4KI2732I

• Full vectored interrupt capability — 8 bitwith MNK1 bit)

• 2MHz or 4MHz operation is jumperselectable

• Selectable auto-wait state insertion torextending M1\ MREQ". IORQ" and/or onboard ROM

• Dual RS-232 serial I/O ports using theZ80A-DART with individual baud rateselection (from 50 — 19.200 baud)

• Up to 24 bit parallel I/O port — fullyprogrammable Intel 8255A

$329 00Assembied & Tes,ed

Optional Monitor Program S50.00

MICROBYTE FLOPPY DISKCONTROLLER

• DMA to within 16 Mbyte of memory

• State-of-the-art NEC765 LSI Controller

• IEEE S-100 compatible

• DMA arbitration allows use of multipleboards within a system

• PLL data recovery for totally reliableoperation

• Write pre-comp switched at mid-disk forreliable double density operation

• Supports up to four (4) drives

• Power On, Power Off or Reset deselectsdrives to avoid damaging files

• Drive deselect Time Out. deselects drivesnot in use

• Single or double sided operation

• Single density/double density operation

• 8" standard drives

• Selectable Vfx supply for data recovery toeliminate possible noise problems

$349 00Assemb|eci & Tested

MICROBYTE 4-PORTI/O BOARD

• Quad RS-232C serial ports. One 20mAcurrent loop port

• Fully IEEE S-100 Bus compatible

• Asynchronous Communications withZ80A-DART(TM) or synchronous commu-nicalions with Z80A-SIO/0ITM)

• Full set of modem control signals,including Rl (Ring Indicator)

• Easily configurable to any type of terminalinterface

• 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 from50 baud to 300K baud

• 72 hour burn-in

2265 00Assembied & Tested

Cables Available (Optional)

MICROBYTE 64K DYNAMICRAM BOARD

• Fully S-100 bus compatible

• 64K x 8 bit dynamic RAM

• Low power:♦8VDC @ 700 mA*16VDC@ 100 mA-16VDC@ 25 mA

• Built-in capacity with LED indicator andvector interrupt

• Memory addressable in four 16K banks

• Hidden refresh

• Gold contacts for high reliability

• 72-hour burn-in

• Memory mapped via DIP switch

• Built-in programmable write-protect

• Programmable control port for parity andbank control

• ALPHA-MICRO compatible

Call for Price

Assembled & Tested

Catalog Request

Please send me your 1981 ASAP Full Line CatalogName

CompanyAddress .

City

State _

Title-

Zip.

Amdek

100G/12" Gm.

S 169.00

Amdek

Color-113"

S 375.00

APF

TVM-10/10" B&W

S 149.00

Hitachi

VM 910/9" B&W

S 210.00

Hitachi

VM 129/12" B&W

S 340.00

Sanyo

DM 5012/12" B&W

S 270.00

Sanyo

DM5112ex/12'Grn.

S 290.00

Sanyo

DM C6013/13" Color

$ 475.00

Terminals

Manufacturer

Model #

Price

Ampex

Dialogue 80

S 899.00

Soroc

IQ120

S 750.00

Soroc

10.140

S1250.00

Televideo

TVI 910

S 650.00

Televideo

TVI 912C

S 725.00

Televideo

TVI 950C

S 975.00

Components

Atari SOftWare (Many more available)

Basketball S 24.00

Super Breakout $ 30.00

Chess S 30.00

Video Easel $ 24.00

3-D Tic Tac Toe $ 24.00

Star Raiders $ 34.00

Asteroids S 30.00

Music Composer $ 42.00

Educational ROM $ 19.95

Assembler/Editor $ 45.00

Telelink I S 19.95

Space Invaders S 14.95

Missile Command S 30.00

Biorhythm $ 12.95

Graph It $ 15.95

Energy Czar $ 12.95

Mailing List S 16.95

Statistics I $ 16.95

Touch Typing S 19.95

Stock Charting S 19.95

Stock Analysis S 19.95

Bond Analysis S 19.95

Word Processor S129.95

Printers

Manulaclurer/Model ff Price

Anacom-150 S 995.00

Anadex-9501 $1249.00

Base 2-800B S 650 00

Diablo-630R0 S2225.00

Cltoh Starwriter 45 $1925.00

Texas lnstruments-810 S1650 00

The Epson MX-80

80 Column Dot Matrix Printer

SPECIFICATIONS

Print methods: serial impact dot matrixPrint rate: 80 CPSPrint direction: bidirectionalNumber of pins in head: 9Matrix: 9x9

Line spacing: 1/8". 1/6", 7/72" /j program-mable throughput at 10 CPI — logical seekingfunction — 105 LPM, 20 character line: 73LPM, 43 char, line: 48 LPM. BO char. line.PRINTING CHARACTERISTICSCharacter set: full 90-character ASCII withdescenders.

Graphics characters: 64 block charactersINTERFACES

Standard: Centronics-style 8-bit parallelOptional: Apple. TRS-80, RS 232NEW

MX80 FT/Friction FeedMX-10O/132 ColumnCALL FOR PRICE & DELIVERY

Modems

Manufacturer Model # Price

Novation CAT $ 149.00

Novation d-CAT S 160.00

Novation Auto-Cat S 229.00

Lexicon Lex-11 S 139.00

Livermore LIV-Star 20M S 149.00

UDS UDS103 S 189.00

UDS UDS 202 S 295.00

Monitors

Manufacturer Model # Price

Amdek 100/12" B&W S 139.00

Amdek 100-80 $ 169.00

ASAP offers a 30-day buyer protection policy: full money-back guarantee if

not totally satisfied.

Ordering information: name, address, phone, ship by: UPS or Mail. Shipping

charge: add $2.50 up to 1 lb. for UPS Blue; add $1.50 for U.S. Mail (U.S. only)

($25.00 mimimum order). Call for larger shipments.

Terms:We accept cash, check, money orders, Visa & Master Charge (U.S.

Funds only). Tax: 6% Calif. Res., COD's and terms available on approval (School

P 0 's Accepted).

4116s (200 nS)

Apple. TRS-80. Heath 8/S18 00

16-49 S2.15 each

50-99 S2.05 each

100 up $1.95 each

2114L-2/200 nS

Low-Power 1Kx 4 Static RAM

1-16 S2.95 each 50-99 S 2.75 each

17-49 S2.85 each 100 up S2.65 each

74LS240.... S1.25 each 74LS373.... S1.25 each74LS241.... S1.10 each 74LS374 .... S1.25 each74LS244 .... S1.25 each 8T245 $1.50 each

2708/450 nS

1Kx8EPR0M S4.00each

or 8/S30.00

2716/5 Volt

2K x 8 EPROM $6.25 each

1 year warranty

8080A-CPU S 2.50 8257AC5 S15.00

Z80A-CPU S 8.95

Z80A-CTC S 8.95 320T5 S .80

Z80A-DART .... S13.95 340T5 S .70

Z80A-SIO $22.00 320T12 S .80

8255AC5 S 6.95 340T12 $ .75

1-9 10-24 25 up

DB25P S2.60 S2.50 $2.35

DB25S $3.50 $3.40 $3.20

DB25C S.95 S 85 $ 75

100 Pin IMSAI

Gold/S-100 Soldertail ConnectorsS2.40 each or 10/S2.25 each

Capacitors

.1(112 Volt

Ceramic

. 8c each or 100/S7.00

DIP Sockets -

Low Profile

Tin Soldertail

Description

1-9

1049 50-99 100 up

14 pin tinst

S .15

S 13 S 12 S .11

16 pin tin st

S .16

S 14 S .13 S 12

18 pin tin st

S .19

$ 18 $ .16 S .14

20 pin tin st

S .25

$ .23 $ 21 $ .20

24 pin tin st

S 26

S 24 S .22 S .20

28 pin tin st

S .32

S 30 S .29 S .27

40 pin tin st

S .42

S .40 S .38 S .34

sisaii

computer ■products, inc.

1198 E. Willow St.. Signal Hill, CA 90806

Toll free outside California:

(800)421-7701

Inside California:

(213) 595-6431(714)891-2663

Circle 31 on inquiry card.

BYTE October 1981

315

Ask BYTE

Conducted by Steve Ciarcia

Mall-Order Forum

Dear Steve,

In July 1979, I was enticedby the savings of buying aRadio Shack TRS-80 from amail-order firm. I chose acompany that is still adver-tising in BYTE today—PanAmerican Electronics (it hada different name in 1979). Iconfirmed with the companythat its TRS-80s were coveredby the Tandy warranty. Stillskeptical, I called the TRS-80Hot Line. To my surprise, Iwas firmly discouraged fromdoing business with PanAmerican and was told thatmost mail-order TRS-80swere defective. I then calledthe Tandy World Headquar-ters and asked for the divi-sion manager responsible forPan American. He assuredme that Pan American waslegitimate. He couldn't un-derstand the comments fromthe Hot Line.

I decided to risk it (afterall, I'd be covered by the war-ranty) and sent my check.My TRS-80 arrived, but it didnot work. Pan American wasvery nice and said I couldeither return it for a refund orexchange, or take it to a localRadio Shack for free warran-ty service. I did the latter anda loose wire was repaired in48 hours.

A few months later, con-trary to my advice, a friendordered from Pan American.His TRS-80 had a defectivekeyboard and was repairedby our local Radio ShackCenter. Just recently, anotherfriend received defective diskdrives from some other"Authorized Radio ShackSales Center."

In all three cases, the war-ranty service was done, and,hence, we are satisfiedcustomers. However, our ex-periences support the Hot

Line's accusations. Is Tandypushing defective merchan-dise through mail-orderstores?Jeff GoodlingAllentown PA

Dear Steve,

I was concerned aboutbuying a TRS-80 by mail, notbecause I was afraid of a rip-off, but because I'd heardrumors that local stores werebeing difficult about post-salesupport.

To see for myself, I went toa Radio Shack ComputerCenter in Glendale, Califor-nia, to check the price on aModel II with a printer, formy own use. The quote I gotwas about $1000 higher thanI could get by mail (even for-getting the tax). When I men-tioned to the salesman thatmail order was muchcheaper, he said, in effect, tryto get support: the mail-ordercompany won't support themachine, and neither wouldhe unless I bought a $1300service contract. He was pret-ty hostile about the wholeidea that I might want to savea thousand bucks. He sosoured me on the idea of aModel II that I've crossed itoff my list of possibles.

At the same time, I waslooking for a word processorfor business purposes. Ichecked most of the big com-panies (Wang, Lanier, IBM,etc) and got a shock: all ofthem carry their own financ-ing amortized over fiveyears, but Radio Shack doesnot. Radio Shack, on theother hand, forces you to anoutside lender, no matterwho you are. We're an oldcompany with plenty ofcredit, but to Radio Shack itmakes no difference. Also,Radio Shack's service con-

tract costs from $400 to $800more than the rest.

It seems that Radio Shacksimply isn't interested in thebusiness market—at least it'snever going to get it with thatkind of financial attitude.Radio Shack's machines areinitially cheaper, true, butover five years, with the ser-vice, they come out lookingvery bad. Plus, the attitudeof the people associated withthe places I talked to leftsomething to be desired.David StortiLos Angeles CA

Perhaps it is best if RadioShack responds directly. PanAmerican Electronics' replyfollows. . . . Steve

Radio Shack Replies:

/ can't believe anyone canthink we're "pushing defec-tive merchandise throughmail-order stores'7 That's ab-surd . . . our reputationwould suffer, and we'd endup paying for the repairs any-way. I'd bet the reason MrGoodling and his friends ex-perienced problems was dueto the extra shipping time andmileage. If a local store ordealer had delivered theequipment to the user, itcould have been checked outon the spot before delivery.

Any Radio Shack employeetelling a customer not to buyfrom a dealer is speakingagainst company policy.There are obvious advan-tages to buying locally,whether through a companystore or authorized dealer:checkout prior to deliveryand a salesman naturallymore anxious to help "hiscustomer" with any problemsafter the sale. A customerwho spends money elsewhereand needs service is very like-

ly to be a lower priority.That's not policy, just a com-monsense assessment of hu-man nature at work. Ourstore personnel are requiredto help any customer with re-pairs in a timely fashion.Warranty service requiresproof of purchase from aRadio Shack store or autho-rized dealer. There are somefolks selling TRSSOs whoaren't authorized dealers, andthere is no pass-through war-ranty if you buy from one ofthem.

I'm sorry Mr Storti doesn'tlike our prices or our creditpolicies. There are alwayspeople who can work on lessmargin, some, it seems, on nomargin. We know what ittakes to continue our servicenetwork and still keep ourstockholders happy: HotLine, Newsletter, new hard-ware and software develop-ment, etc.

As to the credit question,we simply aren't in the time-payment business: Why notcriticize the finance companyfor not manufacturing com-puters? We offer a leasingprogram, but apparently itdidn't meet Mr Storti's re-quirements.

I really believe that RadioShack's attitude toward ourcustomers is good. A sales-person (ours or anyone else's)will resist losing a sale andmay naturally be less than en-thusiastic about furnishingsupport to someone else'scustomer. I apologize to any-one who has received otherthan courteous treatmentfrom one of our employees inthis situation, or who hasbeen led to believe that we asa company condone less thanfull support on a purchasefrom an authorized outlet. Itjust isn't true.

We'd like to be all things toall customers, but we know

316 October 1981 © BYTE Publications Inc

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HP-85 $2575.00HP-83 $1790.00

HP-83 is the same in capabilitiesof the HP-85 less the tape storageand printer.

82903A HP + 85/83 16K Memory Module $255.00

Firmware Enhancements:82936A

82936A ROM Draw15-15001 Mass Stor.

Interlaces:

15-1500215-1500315-1500415-1500515-15007

Plotter/PrintIn/OutputMatrixAdv.Prog.Assembly

$ 42

135$135$274$135$274$127.5

82937A HP-IB

$339

82939A Serial (female)

$399

82939 opt 001 (male)

$339

Same 002 (crrnt 1p)

$339

82940A GPIO

$421

82941A BCD

$420

82949A Printer Int.

$269

7225

Graphics Plotter

$2089.95

HP2631B

Matrix Printer

$3295.00

HP 82902MDisk Drive$1275.00

HP APPLICATION PACS

85-13001 Standard

85-13002 Basic Training

85-13003 Gen. Statistics

85-13005 Math

85-13006 AC Circuit Analysis

85-13010 Games

85-13042 VisiCalc PLUS

85-13045 Information Mgmt.

85-13046 Surveying

85-13044 Data Communications

85-13038 Graphics Presentation

$79.00 each

85-13011 Linear Programming85-13034 Text Editing85-13035 Wave Form Analysis85-13036 Basic Statistics and

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$166

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Z-80 Soft Card 16K Ram Card

with CP/M

pen your Apple II computer to a larger world. With the Z-80 Soft-ard and 16K RAM Card you can now run CP/M compatible software,xpand your memory for specific application, act as a firmware cardnd much more. If you add any boards to your Apple this year thesere the ones.

VIDEX 80 x 24 VIDEOTERMAND KEYBOARD ENHANCER

$269.00Videoterm

$110.00Keyboard Enhancer

ALS "Smartcm" 80 column card $295.00

Maintain optimum software compatibility industry wide. By adding theVideoterm 80 x 24 videoboard and keyboard enhancer your Apple actssimilar to CRT Terminals on larger systems. Combine this with theMicrosoft Softcard and you've got some system.

APPLE II COMPUTER

$1069.0016K Apple II Plus

48K Apple II "Plus" w/factoty warranted RAM$1129.00

What can we say except that it's a supersystem at a steal of a price.

•Applesoft Firmware•Centronix Printer Int.•Communications Card•High speed serial Int.•Pascal Lang. Syst.•Integer firmware•Parallel Print.Int.

$149$179179155379149149

•Disk II w/cont.•Disk II 2nd•Hand Controllers•Vinyl Carrier•Joystick II•Graphics Table•Silentype Printer 365

$509

$445

27

33

45

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OTHER APPLE PRODUCTS

California Computer Systems:

• 12K PROM/ROM Brd CALL

• Centronics Cable

• Calendar Clock

• Programmable Timer

• A/D Converter

• GPIB IEEE 488

$30$99$89$95CALL

Mountain Computer Inc.

• Apple Clock

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• X10 Controller

• X10 System

• CPS Multi-function

Other:

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• ABT Keypad

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$210$255$131$152$152$172$270$239

$159CALL$115$145

• Asynchronous Serial

• Synchronous Serial

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• Arithmetic Proc/Disk

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■ Music SystemA/D + D/AKeyboard FilterKeyboard FilterCopy RomI/O Cable AssemblyExpansion ChassisCard Reader

ABT BarwandKBC Joystick IIKBC Keypad IIThunderClock

$129

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$99

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APPLE II SOFTWARE

Apple Computers:

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• DOS 3.3 Update

• Apple Writer

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• Desk Top/Plan II

• CCA Data Mgt.

$44$28$23$57$65$65

■ Stellar Invadersi Apple Plot

i Adventure

■ AP Music Theoryi Tax Planner

$23$57$33$47$114

$159 • Visiterm $125

$165 • Visiplot $147

$84 • Visidex $159

• VisiTrendA/isiplot $229Microsoft: (requires Z80 SoflCard & CP/M)

• Basic Compiler $296 • COBAL Language $562.50

• Assembly Language $94 • Fortran Language $149.00Peachtree/40: (requires Z-80 SoftCard & 16K RAM Card)

• General Ledger $195

• Accounts Rec $195

• Accounts Payables $195Misc: (48K All or AII + )

• Stoneware 'DB Master' $179

• BPI General Ledger $315

• BPI Inventory Control $315

• BPI Payroll $315

• BPI Job Cost Sys. $315

PayrollInventoryMail List

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Software Publising Corp.

"PFS" $87.50

"PFS: Report" $87.50

MicroFocus "COBOL" $743.00

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• Micromodem II $303.00

• Micromodem 100 CALL

Cat-ModemD-Cat ModemApple Cat

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3M Scotch 5" Diskettes (10) 3M Scotch 8" Diskettes (10)

•744-0 5" SS/SD soft sect. $26 •740-0 8" SS/SD $32

•744-10 5" SS/SD 10 sect. $26 -741-0 8" SS/DD $36

•744-16 5" SS/SD 16 sect. $26 «743-0 8" DS/DD $44

•7440 5" Head Clean.Kit $29 «74O0 8" Head Clean.Kit $30MISC.

•Silentype Paper (roll) $4.50 »Vinyl Disk Sleeves $6.95

•5" Vinyl disk sleeves $6.95

APPLE III COMPUTER

A highly sophisticated system de-signed to tackle the toughest bud-geting, forecasting, scheduling, pric-ing, and other management analysisand planning tasks. It comes with abuilt in disk drive and interfaces andsold as a system package.

A3PO00A system Option A includes:

$4038.00

A3S0128 Apple III 128KA3S0001 Information AnalystA3M0005 12" Black 8, White MonitorAccessories:

• A3M0001 Silentype Printer III $292.00

• A3M0003 Disk II for AMI $495.00

ATARI COMPUTER SYSTEMS

ATARI 800 16K Computer

Your price: $785.00

The Atari 800 Computer with accessories and software makeup a complete system for home, educational, financial andbusiness use.

• Atari 400•810 Disk Drive•815 Dual Disk Dr.•825 80 col.print.

$347 «853 16K RAM Mod $83

$475 »930 Acoustic Mod $156

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$780 »410 Prog.recorder $79

CALIFORNIA COMPUTER SYSTEM

The CCS 2210 is a low cost S100, Z80 computer systemwith 64K of memory, disk controller, parallel/serial I/O andCPM operating system.

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Separate Components

• 2200A Mainframe $373 • 24221 Disk Cntrlr. $195

• 2810A CPU $220 • 2718 Par/Ser I/O $275

• 2065 64K RAM $537

VIDEO TERMINALS & VIDEO MONITORS

Sanyo:

• 12" Green Monitor

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$582$595$595

EPSON PRINTERS

MX-100

Your price $759.00

Probably the best buy in a printer this year. Compare features withany other and compare price (especially ours). 4 character sizes allmay be placed into letter quality enhanced mode. Friction and remov-able tractor, 9 by 9 to 18 by 18 dot Matrix, logic seeking, and muchmore. Not to mention DOT PL0TTING7GRAFTRAX option built rightin. WOWI What a printer!

• MX 80 FT Printer $569 • MX Ser. Interface Opt $65

• MX 80 Printer $479 • Epson Apple Par. Int. $69

• MX 70 Printer $394 • Epson Par.Cable $22.50

• MX 80 Ribbons $14 • MX-80 or 80/ft Graf-

trax ROM $78

ALTOS COMPUTER SYSTEM

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NEC PC-8000 MICROCOMPUTER SYSTEM

Not an apple lover? Check out the new NEC PC-8000-itcombines the most wanted features of several leadingmicrocomputers, together with a few wonders of its own.Go see it today, then call us tomorrow for pricing, you justmight be surprised.

TERMS: Shipping: add 3% for product shipped within continentalUSA via UPS surface (minimum $3.00). If the Order placed Isprepaid with U.S. funds In the form of check or money order,a Total Charge of $3.00 for shipping is all you pay within thecontinental USA via UPS surface. Allow 14 working days forpersonal and company checks to clear. Credit card chargeslimited to $1000. No COD's. FPO, APO or orders outsidecontinental USA call or write for shipping charges or add 10% topurchase price (any difference will be refunded). Californiaresidents add 6% sales tax. All offers subject to change orwithdrawal without notice. Warehouse: 20695 S. Western Ave,,#124. Visitors by appointment.

Circle 274 on inquiry card.

Ask BYTE

we'll lose some customers tothe competition. I'm at a lossto understand why Mr Storti'sdecision to buy from some-one else should cause him tohave such strong feelingsagainst us.Ed Juge, DirectorComputer MerchandisingRadio ShackFt Worth TX

Obviously the sort of scaretactics that Mr Goodling ex-perienced by Tandy (RadioShack) personnel is not ap-preciated by Pan AmericanElectronics or other dealers(i.e., Authorized Sales Cen-ters). It is unfortunate thatsome Tandy personnel willtry to make a sate or expresstheir competitive nature be-tween the two divisions(company and franchised/dealers) in such a way.

The facts are that the mer-chandise is the same. Thevast majority of those whopurchase from independentRadio Shack dealers are veryhappy with the merchandiseand the personal service theyreceive from the small inde-pendent dealer. The addedadvantage of buying from anindependent dealer is thatthey will often give their cus-tomers a better price for ex-actly the same merchandise.

Radio Shack dealers arenot usually located in largecities. Major metropolitanareas are reserved for RadioShack's company stores. Theonly access dealers have tothe larger metropolitan areasis by advertising in magazineslike BYTE and by offeringconsumers a better price forthe same merchandise.

The dealers' profit marginis smaller than the companystores', so we sacrifice a lotby discounting. We feel,however, that discountingmerchandise is an honest wayto make a living. We feel it isinappropriate and unethicalto make unwarranted threatsor to spread lies about our

3000-37FF DECODE

Figure 1

Number

IC1IC2IC3

Type

271674307404

+ 5V

241414

GND

12

7

7

main supplier and our majorcompetitor simply to makean extra dollar.Dan Frank, President

Pan American ElectronicsMission TX

In Need of aWay to the PROM

Dear Steve,

I want to use my TRS-80Model I and Model III todevelop useful programs, andI need peripherals to ac-complish the task. Your ar-ticles on parallel and serialI/O (input/output) were veryhelpful in this regard. (See"I/O Expansion for the RadioShack TRS-80, Part 1: Prin-ciples of Parallel Ports," May1980 BYTE, page 22 and"Part 2: Serial Ports," June1980 BYTE, page 42.)

One area that I would liketo pursue is that of placingapplication software in an ex-ternal PROM (programmableread-only memory). Thus,the application programwould not have to be loadedeach time it is used.

How to implement an ex-ternal PROM memory withthe TRS-80 expansion port isnot clear to me. Can youhelp7

Frank FitzgeraldEast Northport NY

According to RadioShack's Level II BASICreference manual for theTRS-80 Model I, there is areserved (blank) area ofmemory between 3000 and3BFF hexadecimal. It's quitepossible to configure a2 K-byte EPROM (erasablePROM) to fit within that ad-dress space so that it can beaccessed during a program.

Figure 1 is a schematic thatdemonstrates how this couldbe attached. You place an ap-plications program in anEPROM in this addressspace, and whenever youwish to run the program, allyou do is jump to addresslocation 3000 hexadecimaland execute.

As for the TRS-80 ModelIII, this address space appearsto be reserved for a systemPROM. I haven't actually

dismantled a Model III yet tosee if this reference is a"phantom" PROM. . . . Steve

Getting on theRight Trak

Dear Steve,

I found your February 1981"Circuit Cellar" article veryinteresting. (See "A Com-puter-Controlled Tank,"page 44.) Since I fiddle withrobotics, I would love to tryout this ingenious toy. Theonly problem is that I can'tfind a store that sells the BigTrak. Could you give me theaddress of the Milton Bradleycompany?

Am I correct in assumingthat the only parts I mustspecially order to build thisare the Exar Integrated Sys-tems phase-locked loop andthe modem listed at the backof the article?Marc WeigelDelta, British Columbia, Canada

The address you want isMilton Bradley Company,MB Electronics Division,Springfield MA 01101.

318 October 1981 © BYTE Publications Inc

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SAVINGS: Account management system for up to 20 separate Savingsaccounts. Organizes, files and displays deposits, withdrawals and interestearned for each account S14.95

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A user programmable computing system structured around a 50 row x 50column table. User defines row and column names and equations forming aunique computing machine. Table elements can be multiplied, divided,subtracted or added to any other element. Hundreds of unique computingmachines can be defined, used, stored, and recalled, for later use. Excellentfor sales forecasts, budgets, inventory lists, income statements, productionplanning, project cost estimates-in short for any planning, analysis orreporting problem that can by solved with a table.

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Got a busy calendar? Organize it with Color Calendar. Whether it'sbirthdays, 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 theselected month with each scheduled day highlighted in color. Using thedaily schedule, you can review any day of the month and schedule an eventor activity in any one of 20 time slots from 8:00 A.M. to 5:30 P.M.

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ELECTRONICS SERIES VOL I & II: Entire Series $259.95

LOGIC SIMULATOR: SAVE TIME AND MONEY. Simulate your digital logiccircuits 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 alogic network to user-specified input patterns. It will handle up to 1000gates, including NANDS. N0RS. INVERTERS. FLIP-FLOPS. SHIFT REGISTERS.COUNTERS and user-defined MACROS, up to 40 user-defined random, orbinary input patterns. Accepts network descriptions from keyboard or fromLDGIC DESIGNER for simulation S159.95 (A)(f)

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MANUAL AND DEMO DISK: Instruction Manual and demo disk illustratingcapabilities of both program (s) S29.95 (t)(f)

ELECTRONIC SERIES VOL III & IV: Entire Series $259.95

CIRCUIT SIMULATOR: Tired of trial & error circuit design? Simulate & debugyour designs before you build them! With CIRCUIT SIMULATOR you build amodel of your circuit using RESISTORS. CAPACITORS. INDUCTORS. TRANSISTORS.DIODES. VOLTAGE and CURRENT SOURCES and simulate the waveform responseto inputs such as PULSES. SINUSOIDS. SAWT00THS. etc. all fully programmable.The output is displayed as an OSCILLOSCOPE-STYLE PLOT of the selectedwaveforms (Apple only) or as a printed table of voltage vs time. Handles up to200 notes and up to 20 sources. Requires 48 RAM S159.95 ,(jf) (j)

CIRCUIT DESIGNER: Interactive HI-RES graphics program for designing electroniccircuits. Draw directly on the screen up to 10 different component types,including those referenced above. Components interconnect list for CIRCUITSIMULATOR generated automatically. Requires S159.95

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3-D SURFACE PLOTTER: Explore the ELEGANCE and BEAUTY of MATHEMATICSby creating HI-RES PLOTS of 3-dimensional surfaces from any 3-variableequation. Disk save and recall routines for plots. Menu driven to varysurface parameters. Hidden line or transparent plotting S19.95

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FREE CATALOG-AM programs are supplied on disk and run on Apple II w/Disk& Applesoft ROM Card & TRS-80 Level II and require 32K RAM unlessotherwise noted. Detailed instructions included. Orders shipped within 5days. Card users include card number. Add S1.50 postage and handlingwith each order. California residents add 6%%sales tax. Foreign orders add$5.00 postage and handling.

SPECTRUM SOFTWARE

142 Carlow, P.O. Box 2084Sunnyvale, CA 94087

FOR PHONE ORDERS: (408) 738-4387DEALER INQUIRIES INVITED.

Circle 347 on inquiry card.

BYTE October 1981

319

Ask BYTE

Regarding the componentsnecessary to modify the BigIrak as I did, you wouldneed two modem boards. Ifpurchased as kits from theMicro Mint, 917 Midway,Woodmere NY 11598, theyinclude the XR-2211 phase-locked loop and all othercomponents. Other than thatyou would have to buy theUART (universal asynchro-nus receiver/transmitter) andCMOS (complementary met-al-oxide semiconductor) in-tegrated circuits. Many ad-vertisers in the back pages ofBYTE sell these items. . . .Steve

Board Inquiries

Dear Steve,

Is someone going to make

available kits or printed-cir-cuit boards for the projectyou described in "Build aLow-Cost Logic Analyzer"(April 1981 BYTE, page 36)7Ivan WhitehouseGoldendale WA

/ completely misjudged theinterest in my logic-analyzerproject. The only unit I madewas the prototype; I figuredthe interest would be general,but not enough to warrantthe expense of having aprinted-circuit board made.As you know, printed cir-cuits are available for manyof the projects that I presentin BYTE, but I usually havesome indication beforehandthat there will be a reasonabledemand.

Unfortunately, it's a littlelate for me to start the longprocedure of designing aboard, with so many newthings to work on. I'll be sureto gauge response in thefuture, and there will con-tinue to be printed-circuitboards for many of my pro-jects.

If you want a complete listof all the printed-circuitboards available from myprevious articles, drop a noteto the Micromint, 917 Mid-way, Woodmere NY 11598and request a catalog.. . . Steve

In "Ask BYTE," Steve Garcia answers questions on any area ofmicrocomputing. The most representative questions receivedeach month will be answered and published. Do you have a nag-ging problem? Send your inquiry to:

Ask BYTE

c/o Steve Garcia

POB 582

Glastonbury CT 06033If you are a subscriber to The Source, send your questions byelectronic mail or chat with Steve |TCE317) directly. Due to thehigh volume of inquiries, personal replies will be given as timepermits. Please enclose a self-addressed, stamped envelope, andbe sure to include "Ask BYTE" in the address.

RACET SORTS — RACET UTILITIES — RACET computes — RACET SORTS— RACET UTILITIES — RACET computes — RACET SORTS — RACET UTILITIES — RACET computes —

FIELD PROVEN!!

10 MEGABYTES and MORE for the TRS-80* Model II

plus SHARED ACCESS to HARD DISK DRIVE

Hard/Soft Disk System (HSDS) Software allows access as single drive. You canhave that 10 Megabyte continuous file - that 50,000 name maillist or inventory! Ora directory with 1000 entries! All completely compatible with TRSD0S 2.0 BASIC.You can mix floppy and hard disk drives. Includes special utilities including HPURGE,DCS Directory Catalog System, HZAP Hard Disk Superzap, and many specialformatting options. Three to eight times faster than floppy! RACET quality.

HARD DISK DRIVE & CONTROLLER $5995. Second User $595.

HSDS Software $400. (Note: HSDS now also available for CORVUS drives!!)

INFINITE BASIC (Mod I & III Tape or Disk) Mod I $50.00, Mod III $60.00

Extends Level II BASIC with complete MATRIX functions and 50 more stringfunctions. Includes RACET machine language sorts! Sort 1000 elements in 9seconds!! Select only functions you want to optimize memory usage.

INFINITE BUSINESS (Requires Infinite BASIC) Mod I & III $30.00

Complete printer pagination controls — auto headers, tooters, page numbers.Packed decimal arithmetic — 127.digit accuracy +,-,*,/. Binary searchof sorted and unsorted arrays. Hash codes.

BASIC CROSS REFERENCE UTILITY (Mod II 64K) $50.00

SEEK and FIND functions for Variables, Line Numbers, Strings, Keywords. 'All'options available for line numbers and variables. Load from BASIC — Call with'CTRL'R. Output to screen or printer!

DSM Mod I $75.00, Mod II $150.00, Mod III $90.00

Disk Sort/Merge for RANDOM files. All machine language stand-alone package forsorting speed. Establish sort specification in simple BASIC command File. Executefrom DOS. Only operator action to sort is to change diskettes when requested!Handles multiple diskette files! Super fast sort times — improved disk I/O timesmake this the fastest Disk Sort/Merge available on your TRS.

(Modi Min 32K 2-drive system. Mod II 64K 1-drive. Mod III 32K 1-drive)

GSF (Mod I & III Tape or Disk - Specify Memory Size)Mod I $25; Mod II $50; Mod III $30

Generalized Subroutine Facilities. The STANDARD against which all other sorts arecompared! And then compare prices! Machine language — fast and powerful!Multi-key multi-variable and multi-key character string. Zero and move arrays.Mod II includes USR PEEKS and POKES. Includes sample programs.

m RACET SORTS - RACET UTILITIES — RACET computes — RACET SORTS— RACET UTI

DISCAT (32K 1-drive Min) Mod I, ill $50.00

This comprehensive Diskette Cataloguing/Indexing utility allows the user to keeptrack of thousands of programs in a categorized library. Machine language programworks with all TRSD0S and NEWD0S versions. Files include program names andextensions, program length, diskette numbers, front and back, and diskette free space.

KFS-80 (1-drive 32K Min — Mod II 64K) Mod I, III $100.00; Mod II $175.00

The keyed file system provides keyed and sequential access to multiple files. Providesthe programmer with a powerful disk handling facility for development of data baseapplications. Binary tree index system provides rapid access to file records.

MAILLIST (1 -driye.32K.MJn - Mod II 64.K) Mod,.LJJ.I$75,00; Mod II $150.00

This ISAM-based maillist minimizes disk access times. Four keys'— no separatesorting. Supports 9:digit zip code and 3-digit state code. Up to 30 attributes. Maskand query selection. Record access times under:4 seconds!!. '

C0MPR0C (Ifi'od/I & Mod III — Disk only) Mod I $20; Mod 111 $30 /

Command Pif eessor. Auto your disk to perform any sequence of instructions thatyou can give from the keyboard. DIR, FREE, pause, wait for user tnpui. BASIC, No.of FILES and; MEM SIZE, RUN program, respond ta-iriput statements, BREAK,return to DOS, etc. Includes lowercase driver software, debouhce and screenprint!

UTILITY PACKAGE (Mod II 64K) JU $150.00

Important enhancements to the Mod II. The tile recovery capabilities alone will payfor the package in even one application!'Fylly documented in 124 page manual!XHIT, XGAT, XCOPY and SUPERZAP. are used to reconstruct ar recover date frombad diskettes! XCOPY provides multi-file copies, 'Wild-card' mask.select, absolutesector mode and other features. SUPERZAP allows examine/charige any sector ondiskette include track-CL.and absolute disfcbackup/copy with t/O recovery. DCSbuilds consolidateit-dtreefoTiwHrom muNtpie-;dlskette9~into a--single display orlisting sorted by disk name or file name plus more. Change Disk ID with DISKID.XCREATE preallocates files and sets 'LOF' to end to speed disk accesses. DEBUGIIadds single step, trace, subroutine calling, program looping, dynamic disassemblyand more!!

DEVELOPMENT PACKAGE (Mod II 64K) $125.00

Includes RACET machine language SUPERZAP, Apparat Disassembler, and ModelII interface to the Microsoft 'Editor Assembler Plus' software package tactattnguploading services and patches for Disk I/O.

CHECK, VISA. M/C COD.. PURCHASE ORDERTELEPHONE ORDERS ACCEPTED (714) 997-4950

■TRS-80 IS A REGISTERED TRADEMARKOF TANDY CORPORATIONLITIES — RACET computes — RACET SORTS — RACET UTILITIES

£• RACET COMPUTES -^j

1330 N. GLASSELL, SUITE M,ORANGE, CA 92667

- RACET computes -

320 October 1981 © BYTE Publications Inc

Circle 318 on inquiry card.

FMS-8C

Organizes yourOrganization

MS-80, a data base management system, offersthe user a quick and easy way to organize and

efficiently manipulate data so sound decisions j

can be made on facts displayed,

FMS-80000

is the

most power-ful stand

alone DBM

program

available to

the micro

computei

industry.

Completimenu driand writ)in assemlanguageit offersthese features:

<r

2w»

UUUKREGMU1

User definableFile DefinitionsScreen DisplaysReports (with |;

math and fieldbreak analysis)Selection Criteria £(on any or allfields)

Menus (that ap-plications programscan be selected from)Instantaneous data query onindexed records.Mathematical manipulationof numeric data fields usingthe report generator or theprogramming language EFM(Extended File Maintenance)Easy to use video "how to"training tapes are available.Manipulation of up to 19 differ-ent data files (using EFM)at one time and display;, •ing this informationon-the screen,

\

\

m

Li■ ~

rating reports, generating other data files or on-line updating of input files that already existFMS-80 is able to call other programs like sub-routines in EFM

FMS-80 is able to read data files that otherprograms have generated

No restrictions to record size other than avail-able RAM memory spaceOperates under CP/Mf MP/M9 or CDOS"

FMS-80 allows the flexibility to quickly create

programs thatallow data to be

entered in a' ;| form that

~~ >,} ? a secretary

•,** ' * \ ** recognizes

1 generates

reports

that the

manager requires.

If you're continuously asked to

do applications programs and

don't have time to do it in

BASIC, consider FMS-80.

For additional

information contact

Systems Plus,

3975 East Bayshore,

Palo Alto, CA

\»k 94303. Phone

415/969/7047

Systems Plus

Circle 356 on inquiry card.

BYTE October 1981

BEING OVERCHARGED!

DON'T

Pay Credit Card SurchargesPay a U.P.S. C.O.D. "Fee"Even Pay for the Call!

DO CALL OMEGA TOLL FREE

EPSON

MX 80

INTERFACES:

IEEE $55, TRS-80 535,

APPLE INTERFACE & CABLE $90

RS-232 $70

ATARI 80016K$ 769

mm:

WEST COAST1-800-235-3581

EAST COAST1-800-556-7586

CALL OMEGA AND FIND OUT WHY WE ARE AMERICA'S FASTESTGROWING COMPUTER SALES COMPANY!

Omega sales company

322 BYTE October 1981

Circle 275 on inquiry card.

ANADEX$ 1249

DIABLO$199

ATARI 800 32K $ 749

Tractor option^W NEC 12'

MONITOR

$ 245

$ 229

INTERTEC SUPERBRAIN 64K RAM

$2799

QD SUPERBRAIN

$2999

NEC 5510 SPINWRITER (7710)

$2345

NEC 5520 SPINWRITER (7720)

$2695

NEC 5530 SPINWRITER (7730)

$2345

NEC 12" MONITOR

$ 229

OKIOATA MICROLlNE-80

$ 399

OKIDATA MICROLINE-82

$ 529

OKIDATA MICROLlNE-83

$J69

OIABLO630

$1995

APPLE II PLUS 48K

$1139

APPLE DISK w/3.3 DOS Controller

$ 525

APPLE DISK w/o Controller

$ 449

HA2ELTINE1420

$ 799

NORTHSTAR HORIZON II 32K QD

$2925

ANADEX DP-9500/9501

$1249

TELEVIDE0 912C

$ 669

TELEVIDEO 920C

$ 729

TELEVIDEO950

$ 929

CBM 8032 COMPUTER

$1149

CBM 8050 DISK DRIVE

$1349

CBM 4032 COMPUTER

$1029

CBM 4040 DISK DRIVE

$1029

CBM 4022

$ 649

CBM VIC-20

$ 269

RADIO SHACK II 64K

$3245

RADIO SHACK II! 16K

$ 849

LEEDEX/AMDEK 100

$ 139

LEEDEX/AMDEK100G

$ 169

LEEDEX/AMDEK COLOR-1 13" Color Monitor

$ 329

MICROTEK 16K RAMBOARD for Atari

$ 79

MICROTEK 32K

$ 149

QUME SPRINT9/45 (Full Panel)

i>2.z. JD

ATARI 400 16K

$ 349

ATARI 825 PRINTER

$ 650

ATARI 850 INTERFACE

$ 139

ATARI 810 DISK DRIVE

$ 449

ATARI 800

$ 749

JLaflL

J L

PRICES ABE SUBJECT TO CHANGE WITHOUT NOTICE

Call for price list of ATARI softwareWe carry the complete line of Personal Software

We Accept C.O.D.'s • Stock Shipments Same Day or NextNo Surcharge for Credit Cards • All Equipment Factory Fresh with MFT Warranty

WEST COAST1-800-235-3581

OMEGA SALES CO.

3533 Old Conejo Rd. #102

Newbury Park, CA 91320

1-805-499-3678

CA. TOLL FREE 1-800-322-1873

OMEGA

SALES

CO.

EAST COAST1-800-556-7586

OMEGA SALES CO.

12 Meeting St.

Cumberland, Rl 02864

1-401-722-1027

Omega sales company

Circle 275 on inquiry card.

BYTE October 1981 323

Event Queue

October 1981

October-November

Workshops from VirginiaPolytech, Virginia Polytech-nic Institute and State Uni-versity, Blacksburg VA.Workshops on microcomput-er-design interfacing and pro-gramming, digital electronicsfor automation and instru-mentation, and sessions usingthe TRS-80 are part of thecurriculum. All workshopsare hands-on with partici-pants designing and testingconcepts on the actual hard-ware. Contact Dr Lindy Leffel,Virginia Polytechnic Instituteand State University, Blacks-burg VA 24061, (703)961-5241.

October-January

Electronics Magazine Semi-nars, various sites through-out the US. Electronicsmagazine and the McGraw-Hill Seminar Center are spon-soring seminars for engineersand managers. Subjects rangefrom digital electronics tomicroprocessor-system de-sign. Other topics includeprogramming, speech tech-nology and synthesis, micro-processor interfacing, and ahands-on microprocessorworkshop. If a company has10 or more people wanting totake a course, the seminarwill be held at the company'splant. For details, contactCarol Clark, c/o McGraw-Hill Seminar Center, 305Madison Ave, Rm 3112, NewYork NY 10017, (212)687-0243.

October 7-9

Institute on Microcomputersfor Instruction and Researchin Higher Education, Jane SMcKimmon Center, NorthCarolina State University,Raleigh NC. The institute isdesigned to help high-leveleducators learn about the

microcomputer and the role itcan play in higher education.Contact Joyce Currie, c/oNorth Carolina EducationalComputing Service, POB12035, Research TrianglePark NC 27709, (919)549-0671.

October 7-21

The 1981 Far East ComputerTour, Japan, South Korea,Taiwan, and Hong Kong.This tour group will visitvarious computer-relatedconferences and exhibitionsthroughout the Far East.Transportation for this three-week tour, plus shows, meals,and other items are includedin trip packages, ranging inprice from $2290 to $3095.For more information, con-tact Terry Butler, CommerceTours International Inc, 870Market St, Suite 742-744, SanFrancisco CA 94102, (415)433-3072.

October 9-11

Rhode Island Computer andVideo Electronics Show, Pro-vidence Civic Center, Provi-dence RI. This is the first ma-jor computer exhibition andshow to be held in Rhode Is-land. Exhibitors and salesteams will present the latestin computers and video prod-ucts for business, industry,government, education, andhome use. Contact New LeafProductions, Suite 335, 77Ives St, Providence RI 02906,(617) 679-0089.

October 12-15

Information Management Ex-position and Conference:INFO 81, Coliseum, NewYork NY. Discussions on pre-packaged, customized pre-packaged, and custom-de-signed software will comple-ment hardware and softwareexhibits. For more informa-tion, contact Clapp & PoliakInc, 245 Park Ave, New YorkNY 10167, (212) 661-8410.

October 13-15

Understanding and UsingComputer Graphics, NewYork NY. Headed by CarlMachover, this two-day sem-inar examines the state of theart in graphic systems. Thefocus will be on hardware,software, and applications.Contact Bob Sanzo, c/o Frost& Sullivan Inc, 106 Fulton St,New York NY 10038, (212)233-1080.

October 15-18

The Third Annual NortheastComputer Show and OfficeEquipment Exposition, HynesAuditorium, Boston MA.This show will feature hard-ware, software, and suppliesfor business, education, gov-ernment, home, and officeuse. Office systems andequipment will also beshown. Contact NationalComputer Shows, 824 Boyl-ston St, Chestnut Hill MA02167, (617) 739-2000.

October 16-23

The Fourteenth BrazilianComputer Conference and

Exhibit, Anhembi Conven-tion and Exhibit Halls, SaoPaulo, Brazil. This confer-ence will feature technicaltalks, conference tutorials,roundtable discussions, andspecial events. Computer-aided design and manufac-ture in developing countrieswill also be discussed. Con-tact Sucesu Sao Paulo, RuaTabapua, 627-1.° andar,04533, Sa5 Paulo, S P, Brazil.

October 18-20

The Annual Conference ofthe New York State Associa-tion for Educational DataSystems (NYSAEDS), Syra-cuse NY. NYSAEDS is madeup of people with an interestin computers and education.Workshops on the education-al uses of microcomputersoftware will be held. Con-tact Don Ross, Ardsley HighSchool, Ardsley NY 10502.

October 19-23

Wintek's Hand-On Micro-computer Workshop, Lafay-ette IN. Two- and three-dayworkshops in microprocessorhardware, software, and in-terfacing will be offered atWintek's corporate head-quarters. A single-boardcomputer, including a 6800microprocessor, program-mable memory, serial andparallel input/output, and a1 K-byte ROM (read-onlymemory) containing a moni-tor/debug program, will begiven to the participants ofthis workshop.^Tuition is $50per day. Contact WintekCorporation, 1801 South St,Lafayette IN 47904, (317)742-8428.

October 19-23

Systems '81, Munich, WestGermany. Computer systemsand their applications will befeatured. Additional infor-mation is available from Kail-man Associates, 30 JournalSq, Jersey City NJ 07306,(201) 653-3304.

October 20-22

The Annual Government-Industry Data Exchange Pro-gram (GIDEP) Workshop,

Rickey's Hyatt House, PaloAlto CA. The GIDEP annualworkshop is open to anyoneinterested in the exchange oftechnical information relatingto engineering, failure ex-perience, reliability, andmaintainability. Contact theOfficer-in-Charge, GIDEPOperations Center, CoronaCA 91720.

October 20-22

Computerized Office Equip-ment Expo, Southwest, As-

trohall, Houston TX. Ap-proximately 100 exhibitorswill present office equipmentand supplies, including word-processing systems, at thisshow. Contact Cahners Ex-position Group, 222 WAdams St, Chicago IL 60606,(312) 263-4866.

324 October 1981 © BYTE Publications Inc

if He'd used selectsit wouldn't have taken seven days

Learn SELECT in just 90 minutes. A whole new word processing softwareconcept that kicks the coded key habit and frees you from complicated instructionmanuals. SELECT is fast. SELECT is logical. With single key mnemonics, you'll usedozens of commands that instantly access the rich capabilities of this system. There'snothing like it.

Simply hit "C" and you'll be ready to Create a document.

Key "I" and you'll be in the Insert mode.

Key "M" and Move entire blocks of text... and key dozens more.

That's all there is to it. You'll get all that word processing software promises ... plus afew surprises.

SELECT with SUPERSPELL .* The only microcomputer software with an integratedspelling dictionary. To proof your text all you do, of course, is to key "S". SUPERSPELLwith its 10,000 word dictionary scans your text at computer speed then displays andcorrects all your typing errors. You can increase SUPERSPELL's word power andcustomize the dictionary by adding new words, one at a time. Ask to see it today atyour local dealer.

SELECT with SUPERSPELI just a little byte more.

SELECT will run on any machine that uses CP/M or MP/M" or its derivatives.It needs 40K of RAM and two disk drives. Special version now available forRadio Shack Mod II**" and Apple II****

" SELECT and SUPERSPELL are trademarks of Select Information Syslems Inc." CP/M and MP/M are trademarks of Digital Research* ■ * A trademark of Tandy Corp." ' * A trademark of Apple Computer Inc.

INFORMATION SYSTEMS 919 Sir Francis Drake Boulevard ■ Kentfield. California 949Q4 -(415) 459-4003

Circle 332 on inquiry card.

BYTE October 1981 325

Event Queue.

October 20-23

Computer-Network Designand Protocols, Boston MA.Integrated Computer Systems(ICS) will be presenting acourse on fundamentals incomputer communication-network concepts, technol-ogy, and implementation.Emphasis is on the practicalaspects of network design, in-terfacing, protocols andpacket switching. For aschedule of times and placesfor this course, contact RuthDordick, c/o IntegratedComputer Systems, 3304Pico Blvd, POB 5339, SantaMonica CA 90405, (800)421-8166; in California (800)352-8251.

October 21-24

COMPUTA 81, World TradeCenter, Singapore. This in-ternational show attracts pro-fessionals and buyers fromHong Kong, India, and SriLanka. Additional informa-tion can be obtained fromKallman Associates, 30 Jour-nal Sq, Jersey City NJ 07306,(201) 653-3304.

October 24-25

The Second Annual NewJersey Microcomputer Showand Fleamarket, Holiday Inn(north) Convention Center,Newark International Air-port, Newark NJ. This showwill feature 75 commercialexhibitors and more than 100vendors. User-group meet-ings will be held. Registrationis $5 for both days. ContactKengore Corporation, 3001Rt 27, Franklin Park NJ08823, (201) 297-2526.

October 25-30

The Forty-Fourth AnnualMeeting of the AmericanSociety for InformationScience (ASIS), WashingtonHilton Hotel, WashingtonDC. The theme for this meet-ing is "The Information Com-munity: An Alliance for Pro-gress." Among the topics tobe addressed are information

and creativity, informationand society, and overcomingthe barriers between informa-tion sciences. Contact ASIS,1010 Sixteenth St, NW,Washington DC 20036, (202)659-3644.

October 25-28

Issue '81: The Fifth AnnualSPSS Software Users Con-vention, Jack Tar Hotel, SanFrancisco CA. Issue Inc, theindependent, nonprofit asso-ciation of SPSS softwareusers and coordinators, ispresenting its fifth annualconvention. The primary pur-pose of the convention is toinform the user communityabout new SPSS products.Discussions of special appli-cations will also be featured.Registration fees are $95 formembers and $115 for non-members. For more informa-tion, contact Steve Hamburg,c/o Issue Inc, POB 8224,Chicago IL 60680, (312)329-2400.

October 27-29

Computer Graphics 81, Re-gent Centre Hotel, London,England. Some of the topicsto be covered are graphicssystems: hardware and soft-ware; animation; image pro-cessing; simulation; and busi-ness and home graphics. Anequipment exhibition willalso be presented. For moreinformation, contact OnlineConferences Ltd, ArgyleHouse, Northwood Hills,HA6 ITS, Middlesex,England.

October 29-November 1Southeast Computer Showand Office Equipment Expo-sition, Atlanta Civic Center,Atlanta GA. For details, seeOctober 15-18.

October 31-November 1Computers in AmbulatoryMedicine, Washington Shera-ton, Washington DC. TheSociety for Advanced Medi-cal Systems and the Societyfor Computer Medicine are

sponsoring this conference.Basic and advanced tutorialson the fundamentals of medi-cal computing will be fea-tured along with technicalsessions and presentations ofpapers. Fees are $115 for So-ciety members and $165 fornonmembers. Contact SCM,9650 Rockville Pike, Beth-esda MD 20014, (301) 530-7120.

October 31-November 2

Annual Meeting of theAmerican Society for Cyber-netics, Washington HiltonHotel, Washington DC. Thetheme for this meeting is "TheNew Cybernetics." A goal ofthe meeting will be to rede-fine the field of cyberneticsand to provide a focus for theresearch efforts of the Socie-ty. Among the topics to bediscussed are robotics, prob-lem solving, pattern recogni-tion, remote sensing, andcommunication networks.Contact Dr Laurence DRichards, Department of Ad-ministrative Science, ColbyCollege, Waterville ME04901, (207) 873-1131, ext587.

November 1981

November 1-4

DPMA San Francisco '81,San Francisco Civic Centerand Brooks Hall, San Fran-cisco CA. This is DPMA's(Data Processing Manage-ment Association's) thirtiethannual conference and busi-ness exposition. Contact theConference Coordinator,DPMA, 505 Busse Hwy, ParkRidge IL 60068, (312)825-8124.

November 5

Invitational Computer Con-ference, Amsterdam, Nether-lands. The Invitational Com-puter Conference is a one-day computer show designedfor quantity buyers. Exhibitsand seminars are featured.

For details, contact B JJohnson & Associates Inc,2503 Eastbluff Dr, Suite 203,Newport Beach CA 92660,(714) 644-6037.

November 8-10

The Twelfth ACM NorthAmerican Computer ChessChampionship, BonaventureHotel, Los Angeles CA. Afour-round, Swiss-style tour-nament is planned for thisyear's championship compe-tition. In addition, a round-robin blitz tournament willbe held. Games in this eventproceed at a rate of 5 secondsper move. Belle, the currentworld champion, Chaos,Duchess, Nuchess, and L'Ex-centrique are among the pro-grams being entered. Formore information, contactProfessor Monroe Newborn,School of Computer Science,McGill University, 805 Sher-brooke St West, Montreal,Quebec H3A 2K6, Canada.

November 9-10

Software Fair, Stouffers' Riv-erfront Towers, St LouisMO. This show is made up ofsoftware exhibitions fromcompanies whose packagesare in current use by mem-bers of the Southern and Na-tional Industrial DistributorsAssociation. Distributorswho are not members ofthese organizations can alsoexhibit their wares. ContactDon White or Tony Carroll,1900 Arch St, PhiladelphiaPA 19103, (215) 564-3484.

November 9-11

ACM '81, Bonaventure Ho-tel, Los Angeles CA. Thismeeting will feature paneldiscussions on computers,software products in the1980s, tutorials on computer-aided design, and a survey onthe impact of robots on em-ployment. Ray Bradbury andDr Simon Ramo will speak.Computer exhibits and theNorth American ComputerChess Tournament will alsobe held. Contact ACM '81,

326 October 1981 © BYTE Publications Inc

APPARAT OFFERS

More bytes per buck!

Si.'hytf* of ^un-iqc 4pj>au! >n».',!.<i «.<! .'•-> rtrvi"!n- .«<> upcs.Hsnn «•</?>tem and a dual-sided 80 track mini-floppy drive to give you up to 753,440bytes of storage in a single volume.Newdos/80 version 2.0 expands thecapability of double density drives,so you'll have greater applicationsfor your TRS-80® model I and 111.

Drives plug directly into an ex-pansion interface (requires instal-lation of a double density control-ler) or the model III disk bus withour single volume cable so youcan now have over 2 megabytes ofstorage on-line with standardmini-floppy diskettes. Each drivehas up to 573 free grans, for atotal of X719, on a maximum ofthree 80 track drives, which can beadded to a TRS-80 model I. ModelIll's can have up to 4 dual 80son-line (almost 3 megabytes).

These drives can "read" standard35 or 40 track diskettes usingNewdos/80 version 2.0 which willallow skipping every other track.Drives comecomplete withcase, power sup-ply and docu-mentation. Thedrives are pricedat only $515 (Cat.No. 1-705, specify I or III). Now, at 1424bytes per buck, it just might be the answerto your storage problems. Special — Ttoodual 80 track drives only $999.

Apparatlnc.

4401 So. lamarac Parkway, Denver, CO 80237 (303) 741-1778Circle 27 on inquiry card.

O/Y GOING SUPPORT FOR MICROCOMPUTERS'

Event Queue.

POB 24059, Village Station,Los Angeles CA 90024, (213)536-9735.

November 10-12

Midcon/81 Show and Con-vention, O'Hare ExpositionCenter and Hyatt RegencyO'Hare, Chicago IL. Talks onmicrocomputers, energy,memory, communications,and consumer electronics willhighlight this show. ContactElectronic Conventions Inc,999 N Sepulveda Blvd, ElSegundo CA 90245, (800)421-6816; in California (213)772-2965.

November 12

Invitational Computer Con-ference, Paris, France. For de-tails, see November 5.

November 16-19

The Canadian ComputerShow and Conference, Inter-national Centre of Com-merce, Mississauga, OntarioCanada. For details, contactReg Leckie, Industrial TradeShows of Canada, 36 But-terick Rd, Toronto, Ontario,M8W 3Z8, Canada, (416)252-7791.

November 17

Invitational Computer Con-ference, Milan, Italy. For de-tails, see November 5.

November 17-19

Understanding and UsingComputer Graphics, AtlantaGA. For details, see October13-15.

November 19-20

Western Educational Com-puter Conference, San Fran-cisco CA. Many of the com-puter-related talks at thisconference will cover areas ofinterest to college instructorsand administrators. For de-tails, contact Ron P Langley,Data Processing Services,California State University-Long Beach, 1250 BellflowerBlvd, Long Beach CA 90840.

November 29-December 1

National Telecommunica-

tions Conference, New Or-leans LA. This event is spon-sored by the IEEE (Institute ofElectrical and Electronics En-gineers) and the New Orleanschapter of the Communica-tions Society ConferenceBoard. Some of the papers tobe presented will discusscommunications electronics,including software, termi-nals, theory, and data andcomputer communications.Contact G Allan Ledbetter,South Central Bell, 365 CanalSt, Rm 1360, New OrleansLA 70140, (504) 528-7350.

December 1981

December 1-3

Legal Info, Shoreham Hotel,Washington DC. Automatinglegal-information systems isthe subject of this conferenceand exposition. Lawyers whoare interested in using com-puters in their work are in-vited to attend. ContactLegal Info, 1730 N Lynn St,Suite 400, Arlington VA22209, (703) 521-6209.

December 1-4

Computer-Network Designand Protocols, WashingtonDC. For details, see October20-23.

December 3

California Computer Show,

Hyatt Hotel, Palo Alto CA.For details and a schedule ofupcoming shows, contact theShow Administrator, c/oNorm De Nardi Enterprises,95 Main St, Los Altos CA94022, (415) 941-8440.

December 9-11

1981 Winter Simulation Con-ference (WSC 81), PeachtreePlaza, Atlanta GA. WSC 81will feature papers, paneldiscussions, tutorials on dis-crete and combined simula-tion and modeling. The con-ference will be organized intotutorial, methodology, andapplication sessions. For in-

formation, contact Claude MDelfosse, CACI Inc, 1815 NFort Myer Dr, Arlington VA22209, (703) 841-7800.

December 15-19

Gulf Computer Exhibition,

Dubai International TradeCentre, Dubai, United ArabEmirates. IBM, NCR, Apple,Honeywell, Philips, Wang,Hewlett-Packard, Data Gen-eral, and other well-knownmanufacturers will be repre-sented at this first exhibitionof computer equipment inDubai. The scope of the showtakes in systems ranging frommicrocomputers to main-frames. Details are availablefrom the Trade CentreManagement Company, POB9292, Dubai, United ArabEmirates, Telex 47474 DITCEM, and from Diana CliftonSewell, International Office,Seymour House, 17 WaterlooPI, London, SElY 4AR,England.

December 16-18

The Twentieth IEEE Con-ference on Decision and Con-trol (CDC), Vacation VillageHotel, San Diego CA. TheCDC is the annual meeting ofthe IEEE (Institute of Elec-trical and Electronics Engi-neers) Control Systems Soci-ety. It is held in cooperationwith the Society for Industri-al and Applied Mathematics.

The conference will includecontributed and invited ses-sions plus tutorials and pre-sentations in all aspects of thetheory and applications ofsystems involving decision,control, and adaptation.Topics of interest includelinear and nonlinear systemtheory, stability theory,large-scale system theory anddecentralized control, estima-tion, identification, signalprocessing and stochasticcontrol, and control systems.For more information, con-tact the Institute of Electricaland Electronics Engineers Inc,445 Hoes Ln, Piscataway NJ08854.

December 28-30

Computer Modeling ofLinguistic Theory, GrandHyatt Hotel, New York NY.The ACL (Association forComputational Linguistics) issponsoring three sessions oncomputer modeling of lin-guistic theory in conjunctionwith the annual meeting ofthe Linguistic Society ofAmerica. New models forgrammars and new strategiesfor parsing will be the areasof most attention. Readingsof contributed papers willalso be featured. ContactStan Petrick, IBM ResearchCenter, POB 218, YorktownHeights NY 10598.■

In order to gain optimal coverage of your organization's com-puter conferences, seminars, workshops, courses, etc, noticeshould reach our office at least three months in advance of thedate of the event. Entries should be sent to: Event Queue, BYTEPublications, POB 3721 Hancock NH 03449. Each month wepublish the current contents of the queue for the month of thecover date and the twoj following calendar months. Thus a givenevent may appear as many as three times in this section if it is sentto us far enough in advance.

328

October 1981 © BYTE Publications Inc

Computer experts(the pros) usually have bigcomputer experience.That's why when they shopsystem software for ZBOmicros, they look torthe big system featuresthey're used to. And that'swhy they like Multi-UserOASIS. You will too.

DATA INTEGRITY: FILE &AUTOMATIC RECORD LOCKING

The biggest challengefor any multi-user systemis co-ordinating requestsfrom several usersto change the same recordat the same time.

Without properco-ordination, theconfusion and problemsof inaccurate or evendestroyed data can bestaggering.

Our File and AutomaticRecord Locking featuressolve these problems.

For example: normallyall users can view aparticular record at thesame time. But, if thatrecord is being updatedby one user, automaticrecord locking will deny allother users access to therecord until the up-date iscompleted. So recordsare always accurate,up-to-date and integrityis assured.

Pros demand file &automatic record locking.OASIS has it.

SYSTEM SECURITY:LOGON, PASSWORD& USER ACCOUNTING

Controlling who gets onyour system and what theydo once they're on it is theessence of system security.

(THEN COMPARE.)

Without this control,unauthorized users couldaccess your programs anddata and do what they like.A frightening prospectisn't it?

And multi-userscan multiply the problem.

But with the Logon,Password and Privilege

Level features of Multi-User

OASIS, a system managercan specify for each userwhich programs and filesmay be accessed —and for what purpose.

Security is furtherenhanced by UserAccounting —a feature thatlets you keep a historyof which user has beenlogged on, when andfor how long.

Pros insist on thesesecurity features.OASIS has them.

EFFICIENCY:RE-ENTRANT BASIC

A multi-user systemis often not even practicalon computers limitedto 64K memory.

OASIS Re-entrantBASIC makes it practical.

How?

Because all users use asingle run-time BASICmodule, to execute theircompiled programs, less

memory is needed. Evenif you have more than 64K,your pay-off is cost savingand more efficient useof all the memory you haveavailable —because itservices more users.

Sound like a pro feature?It is. And OASIS has it.

AND LOTS MORE..

Multi-UserOASIS supportsas many as 16 terminalsand can run in as little as56K memory. Or, withbank switching, as muchas 784K.

Multi-Tasking lets eachuser run more than onejob at the same time.

And there's our BASIC-a compiler, interpreter anddebugger all in one.An OASIS exclusive.

Still more: Editor; Hard& Floppy Disk Support;Keyed (ISAM), Direct &Sequential Files; Mail-Box;Scheduler; Spooler;all from OASIS.

Our documentation isrecognized as some of thebest, most extensive, in theindustry. And, of course,there's plenty ofapplication software.

Put it all together and it'seasy to see why the realpros like OASIS. Join them.Send your order today.

OASIS IS AVAILABLE FOR

SYSTEMS: Altos. Compucorp: Cromemco:Delia Products; Digital Group; DigitalMicrosystems: Dynabyle: Godbout: IBCIndex: Intersystems; North Star: Onyx:SD Systems. TRS 80 Mod II: VectorGraphic: Vorimex

CONTROLLERS: Bell Controls: Cameo.

Corvus. Konan; Micromation: Micropolis.Tarbell. Teletek: Thinkertoys: X Comp

Write for complete.

free Application Software Directory

PLEASE SEND ME:

Pricewith

Manual

Product

Manual

Only

OPERATING SYSTEM

(Includes:

EXEC Language;

File Management;

User Accounting;

Device Drivers;

Print Spooler;

General Text

Editor; etc.)

SINGLE-USER

S150

SI7.50

MULTI-USER

350

17 50

BASIC COMPILER/

INTERPRETER/DEBUGGER

too

15 00

RE-ENTRANT BASIC

COMPILER/INTERPRETER/

DEBUGGER

150

15.00

DEVELOPMENT PACKAGE

(Macro Assembler;

Linkage Editor;

Debugger)

150

25.00

TEXT EDITOR 4

SCRIPT PROCESSOR

150

15.0C

DIAGNOSTIC 4

CONVERSION UTILITIES

(Memory Test;

Assembly Language;

Conveners: File

Recovery. Disk Test;

File Copy Irom

otner OS; etc.)

100

15.00

COMMUNICATIONS

PACKAGE

File Send & Receive)

100

15.00

PACKAGE PRICE

(All ol Above)

SINGLE-USER

500

60.00

MULTI-USER

850

60 00

FILE SORT

100

15.00

COBOL-ANSI 74

750

35.00

Order OASIS from:

Phase One Systems, Inc.

7700 Edgewater Drive, Suite 830

Oakland, CA 94621

Telephone (415) 562-8085TWX 910-366-7139

NAME.

STREET (NO BOX

~)

CITY

STATEAMOUNTS

ZIP

(Attach system description;

add S3 for shipping;

California residents add sales tax)

□ Check enclosed □ VISA

□ UPS C.O.D. □ Mastercharge

Card Number

Expiration Date

Signature

Circle 406 on inquiry card.

MAKES MICROS RUN LIKE MINIS

BYTE October 1981

329

DYNACOMP

Quality software for

*.

ATARI

PET

APPLE II Plus

TRS-80 (Level II)**NORTH STARCP/M Disks/Diskettes

CARD GAMES

BRIIHJL 2.01 Aiuiluhlt- for all computers) Price: (11.93 Cassette.$21.95 Diskette

An all-inclusive version of this mosl popular of card games. This program bolh BIDS and PLAYS either contract 01duplicate hridge. Depending on the contract, your computer opponents will either play lite offense OR defense. Ifyou bid loo high, the computer will double your contract! BRIDGE 2.0 provides challenging entertainment foradvanced players and is an excellent learning lool for the hridge novice. Sec the software review in 80 SoftwareCritique. Raied »l by Creative Computing.

HEARTS 1.5 (Available for till computers) Prlee:SI5.<HCaijeile/$19,<)S Diskette

An exciting and entertaining computer version of this popular card game. Hear Is is a trick-oriented game in which thepurpose is not to take any hearls or ihe queen of spades. I'lay againsl two computer opponents who are armed withhard-ln-hcal playing strategics. HEARTS 1.5 is an ideal guinc for introducing the uninitiated (your spouse) lo com-puters. Sec the software renew in 80 Software Critique.

Price: SI 1.95 Cassette'$I5.« Diskette

. The computer deals the cards one al a time and you (and the computer) bet on:heat and usually bets the odds. However, it sometimes bluffs! Also included isprogram. This package will run on a !6K ATARI. Color, graphics, sound. See

STUD POKER (Atari oiu»

This is the classic gambler's card gamwhat you see. The computer does nota five card draw poker belling praclicrenew in COMPUTE.

POKER PARTY I Available for all computers) Price: $17.95 CaMriic/521.93 Diskette

POKER PARTY is a draw poker simulation based an the book, POKER, by Oswald Jacohy. This is the mosl com-prehensive version available for microcomputers. The parly consists of yourself and six other (computer) players.Each of ihcse players (you will gel to know them) has a different personality in the form of a varying propensity loblufr or fold under pressure. Practice with POKER PARTY before going to that expensive game tonight! AppleCassette and disketle versions require a 32 K (or larger) Apple II.

(. it 1 mi \(,I 2.0 <TRS-80 only) Price:S14.95Casielie/Slll.9S Diskette

This is simply ihe best cnbbage game available. It is an excellent program for ihe cnbbage player in search of aworthy opponent as well as Tor the novice wishing to improve his game. The graphics arc superb and assemblylanguage routines provide rapid execution. See the software review in 80 Software Critique.

THOUGHT PROVOKERS

MANAGEMENT SIMULATOR (Alari, Norlh Star »nrj CP/M only) Price: 519.95 Cawetie

$23.9$ Diskette

This program is bolh an excellent leaching tool as well as a stimulating intellectual game. Based upon similar gamesplayed ai graduate business schools, each player or learn controls a company which manufacturers three products.Each player attempts lo outperform his competitors by setting selling prices, production volumes, marketing anddesign expenditures clc. The most successful firm is the one wit)) the highest stock price when ihe simulation ends

FLIGHT SIMULATOR (Available for all computers) Price: S17.95 CaWHl/SW.W Diskette

A realistic and extensive mathematical simulation of take-off, flight and landing. The program ulili/cs aerodynamicequations and the characteristics of a real airfoil. You can practice instrumcni approaches and navigation usingradials and compass headings. The more advanced flyer can also perform loops, half-rolls and similar acrobaticmaneuvers. Although this program docs not employ graphics, it is exciting and very addictive. See the softwarereview in COMPUTRONKS. Runs in 16K Atari,

VAI.DEZ (Available for all computers) Price: $15.95 tassette/$l<».95 Diskette

VALDE2 is a computer simulation of supertanker navigation in the Prince William Sound/Valdez Nariows regionof Alaska. Included in this simulation is a realistic and extensive 25f> X 256 clement map, portions of which may beviewed using Ihe ship's alphanumeric radar display. The motion of the ship itself is accurately modelledmathematically. The simulation also contains a model for the tidal patterns in the region, as well as other traffic(outgoing lankers and drifting icebergs), Chart your course from ihe Ciulf of Alaska to Valde/ Harbor! Sec the soft-ware review in 80 Software Critique.

BACKGAMMON 2.0 (Atari, North Slar and CP/M only) Price: $14.95 C«ielte/$1I).9S Diskette

This program tesis your backgammon skills and will also improve your game. A human can compete against a com-puter or against another human. The computer can even play againsl itself. Either the human or the computer candouble or generate dice rolls. Hoard positions can he created or saved for replay. BACKGAMMON 2.0 plays in ac-cordance with the official rules of backgammon and is sure to provide many fascinating sessions of backgammonplay.

CHECKERS 3.0 (PET only) Price: $16.95 Caj.elle/HO.95 Diskette

This is one o( the mosl challenging checkers programs available. It has 10 levels of play and allows the user lo changeskill levels at any time, Although providing a very tough game at level 4-H. CHECKERS 3.0 is practically unbeatableat levels 9 and 10.

CHESS MASTER (North Star and TRS-80 only)

This complete and very powerful program provides five levels o( play. It inthe promotion ol pawns. Additionally, the board may be preset before the •of "'book" plays. To maximi/c execution speed, the program is writtenSPECIALISTS ol California), Full graphics are employed in ihe TRS-80 v.display are provided lo accommodate North Star users.

Price: $19.95 Casieiie/SIJ.95 Disketle

iudes castling, en passant captures andart of play, permitting the examination1 assembly language (by SOFTWARE

rsion, and two widths of alphai

LEM LANDER (32K Apple Disk only)

Pilot your LEM LANDER lo a safe landing iThe game paddles are used to control crafl a

Price: $16.95 Disketle

i any of nine different surfaces ranging from smooth to treacherous,nude and thrust. This is a real-lime high res challenge!

FOREST EIRE! (Atari only) Price: S16.9S CiSMMe/SM.M Diskette

Using excellent graphics and sound effects, this simulation puts you in ihe middle of a forest fire. Your job is lo directoperations lo put out (he fire while compensating for changes in wind, weather and icrrain. Not protecting valuablestructures can result in startling penalties. Life-like variables arc provided to make FOREST FIRE! very suspcnsefuland challenging. No Ivso games have ihe same selling and there arc .1 levels of difficulty.

NOMINEES JIGSAW (Atari. Apple and TRS-80 only) Price: Slfi.95 Cisxette/S20.9S Diskette

A jigsaw puzzle on your computer! Complete the puzzle by selecting your pieces from a table consisting of N) dif-ferent shapes NOMINOES JIGSAW is a virtuoso programming effort. The graphics are superlative and ihe puzzlewill challenge you with its three levels of difficulty. Scoring is based upon ihe number of guesses taken and by the dif-ficulty ol the board set-up. See review in ELECTRONIC GAMES,

Price: SI 1.95 CasieHe/$l5.95 Diskette

i requiring you lo survive an 8-year term as your nation's leader,nduslnal and agricultural use. how much food lo distribute to the(ion control. You will find that all decisions involve a compromise

MONARCH (Atari only)MONARCH is a fascmai

You determine the amount of acreage devoted topopulace and how much should he speni on polliand lhat U is not easy lo make everyone happy.

CHOMPELO (Atari only) Price: $11.95 C.iieile/$ 15.95 Disketle

CHQMPE1 O is really two challenging games in one. One is similar lo NIM: you must bile off part of a cookie, butavoid taking ihe poisoned portion. The other game is the popular board game REVERSE It fully uses the Atari'sgraphics capability, and is bard to beat This package will run on a IfiK system.

•.-tr.-lzV/. /'£/", TRS-SO, SORTHSTAR. CP/M uniJ IBM

registered iradrnam

DYNACOMP OFFERS THE FOLLOWING

• Widest variety

• Guaranteed quality

• Fastest delivery

• Friendly customer service

• Free catalog

• 24 hour order phone

AND MORE.

Price: $11.95 Cuselie/$I5.95 Diskette

:xample, the Klingons now shoot at theits. The Klingons also attack with boththe Enterptisc is besieged by three heavyware res lews in A.N.A.L.O.C... SOSofi-

STARTREK 3.2 (Available for all computers)

This is the classic Startrek simulation, hut with several new features, lorEnterprise without warning while also attacking starbases in other quadrlight and heavy cruisers and move when shot at! The situation is hectic whecruisers and a starbaseS.O.S, is received! The Klingons get even! Seethe soware Critique and Game Merchandising.

BLACK HOLE (Apple only) Price: $14.95 Cuutte/SIS.95 Diskette

This is an exciting graphical Simulation of the problems involved in closely observing a black hole with a space probe.The object is to enter and maintain, for a prescribed time, an orbit close to a small black hole. This is to be achievedwithout coming so near the anomaly lhat the tidal stress destroys the probe. Control of the crafl is realisticallysimulated using side jets for rotation and main thrustcrs for acceleration. This program employs Hi-Res graphics andis educational as well as challenging.

Price: $10.95 C«jmIIc/$!4.95 Dlikelle

hole in the screen. Sound simple? Notyour skill against others in this habit-

SPACE TILT (Apple and Atari only)

Use the game paddles to till the plane of the TV screen lo "roll"when the hole gels smaller and smaller! A built-in timer allows yoforming action game.

MOVING MAZE {Apple and Atari only) Price: $10.95 Osudle/SUJH Diskette

MOVING MAZE employs Ihe games paddles lo direct a puck from one side of a raize to the other. However, themaze is dynamically (and randomly! built and is continually being modified. The objective is to cross the mazewithout touching (or being hit by) a wall. Scoring is by an elapsed lime indicator, and three levels of play are

ALPHA FIGHTER (Atari only) Price: $14.9$ Cmttit S1S.95 Diskette

Two excellent graphics and action programs in one! ALPHA FIGHTER requires you to destroy the alien starshipspassing through your sector of the galaxy. ALPHA BASE is in the path of an alien UFO invasion; let five UEO's getby and the game ends. Both games require (he joystick and gel progressively more difficult the higher you score!ALPHA FIGHTER will run on I6K systems.

THE RINGS OF THE EMPIRE (Atari only) Price: $16.95 Casxeile/$20.95 Diskette

The empire has developed a new battle station protected by rotating rings of energy. Each lime you blast through therings and destroy the stalion, the empire develops a new station with more protective rings. This exciting game runson IfiK sysiems, employs extensive graphics and sound and can be played by one or two players,

INTRUDER ALERT (Atari only) Price: $16.95 Cassette 520.95 Diskette

This is a fasl paced graphics game which places you in the middle of I he "Drcadsiar" having just stolen its plans. Thedroids have hecn alerted and are directed to destroy you at all costs. You must find and enter your ship to escape withthe plans. Five levels of difficulty are provided. INTRUDER ALERT requires a joystick and will run on 16K systems.

GIANT SLALOM (Atari only) Price: S14.95 Canttlt/SH.93 Diskette

[his real-time action game is guaranteed addictive! Use the joystick to control sour path through slalom courses con-sivting of both open and closed gates. Choose from different levels of difficulty, race against oiher players or simplylake practice runs against the clock. GIANT SLALOM will run on IfiK sysiems.

TRIPLE BLOCKADE (Atari only) Price: S14.95Ciiwiie/Sl!.95 Diskette

TRIPLE BLOCKADE is a two-io-ihrcc player graphics and sound action game. It is based on the classic video arcadegame which millions have enjoyed. Using the Atari joysticks, the ohject is to direct your blockading line around thescreen without running into your opponents). Although the concept is simple, the combined graphics and soundeffect lead lo "high anxiety".

GAMES PACK I (Available for all Computers) Price: $10.95 Cassette'514.95 Diskette

GAMES PACK I contains the classic computer games of BLACKJACK, LUNAR LANDER. CRAPS,HORSERACE, SWITCH and more. These games have been combined into one large program for case in loading.They arc individually accessed by a convenient menu. This collection is worth the price just for the DVNACOMI* ver-sion of BLACKJACK,

GAMES PACK II (Available for all computers) Price: $10.95 Cassette'5)4.95 Disketle

QAMES PACK II includes ihe games CRAZY EIGHTS, JOTTO. ACEY-DUCEV. LIFE. WUMPUS and others. Aswith GAMES 1'ACK I. all the games arc loaded as one program and arc called from a menu. You will pamcularlv en-joy DYNACOMP's version of CRAZY FIGHTS.

Why pay $7.95 o

i program v

ti buy a DYNACOMP collec

t jusi S1U.95:

MOON PROBE (Atari and North Star only) Price: $11.95 Cat*eft*/$I5-99 Diskette

This is an cxircmcly challenging "lunar lander" program. The user musi drop from orbit to land at a predeterminedtargei on the moon's surface. You control the thrust and orientation of your crafl plus direct ihe rate of descent andapproach angle.

Price: $14.95 Diskette

four players (including the

SPACE LANES (North Star only)

SPACE LANES is a simple but exciting space transportaiion game which involves up to

computer). The object is to form and expand space transportation companies in a compeli

is to amass more net worth lhan your opponent, The economics include slock purchases and company mergers

Waich your wealth grow!

ADVENTURE

CRANSTON MANOR ADVENTURE (North Star and CP/M only) Price: $21.95 Diskette

At last! A comprehensive Advcniure game for North Star and CP/M sysiems. CRANSTON MANOR ADVEN-TURE takes you into mysterious CRANSTON MANOR where you attempt to gather fabulous ireasurcs. Lurking inthe manor are wild animals and robots who will nol give up Ihe treasures without a fighl The number of rooms isgreater and the associated descriptions arc much more elaborate lhan (he current popular series of Adventure pro-grams, making this game the lop in its class. I'lay can be slopped at any time and the status stored on diskette.

SPEECH SYNTHESIS

DYNACOMP is now distributing the rSimply connect TNT to your computerthe easiest-to-program speech synthesihie Vocabulary available anywhere!

■w and revolutionary type-'N-talk™ (TNT)speech tynthetiwr from Votrax.s serial interface, enter lext from the keyboard and hear ihe words spoken, TNT is:r on the markel. Il uses (he least auiounl Of memory and provides the mosl flexi-

95 (Please add $-1.1X1 (oi shipping and handling)

TNT Software

The following DYNACOMP programs are i

STUD POKER [Atari. 24KINOMINOES JIGSAW (Atari, 24K)TEACHER'S PET I [Alan and NorllBRIDGE 2.0(Nonh Star)CHOMPELO (Atari. 24KI

Please specify 'TNT' versions »

ABOUT DYNACOMP

DYNACOMP is a leading distributor of small system software with sales spanning the world (currently inexcess of 40 countries). During the pasi two years wc have greatly enlarged the DYNACOMP produciline, nui have maintained and improved our high level of quality and cusiomcr support. The achievementin qualiiy is apparent from our many repeal Customers and the software reviews in such publications asCOMPUTRONICS. 80 Software Criliquc and A.N.A.L.O.G. Our customer support is as close as yourphone, It is always friendly. The staff is highly [rained and always willing 10 discuss products or give

Circle 135 on inquiry card.

BUSINESS and UTILITIES

SPELLGUARD™ (CP/M only) Price: SUMS Disk

SPELLGUARD is a revolutionary new product which increases the value of your current word processing system (WORD-STAR. MAGIC WAND. ELECTRIC PENCIL. TEXTED EDITOR II and others). Written entirely in assembly language,SPELLGUARD'™ rapidly assists the user in eliminating spelling and typographical errors hy comparing each word of ihcISM against a dictionary (expandable) of over 20,000 of Ihc most common English words. Words appearing in the tCM hut notfound in the dictionary are "flagged" for easy identification and correction. Most adminisirative staff familiar wuh word pro-cessing equipment will be able to use SPELLGUARD™ in only a few minutes.

MAIL LIST 2.2 (Apple. Atari and North Star diskette only) Price: $34.93

This program is unmatched in iis ability lo store a maximum number of addresses on one diskette (minimum of 1100 per disk-ette, more than 2200 for "double density" systems!), lis many features include alphabetic and rip code sorting, label printing(1, 2, or J up), merging of files and a unique keyword seeking routine which retrieves entries by a virtually limitless selection ofuser defined codes. Mail l.isl 2.2 will even find and delete duplicate entries. A very valuable program!

FORM LETTER SYSTEM rel. 2 (Atari. North Star and Apple Diskettes only) Price. SJ4.9S

FORM LETTER SYSTEM (FLS) is the ideal program for creating and editing form letters and address lists. It contains an

easy-to-use icxt editor which produces fully justified text. Special codes are used in the address list to obtain personalizedsalutations. Form letters arc produced by automatically inserting each address into a predetermined portion of your letter. ELSis completely compatible wflh MAIL LIST 2.2. which may be used to manage and sort your addtess files.FLS and MAIL LIST 2.2 arc available as a combined package for 159.95.

SORT IT (North Star only) Price: S29.9S Nstutte

SORTIT is a general purpose sorting program written in S080 assembly language. This program will sort sequential daia filesgenerated by NORTH STAR BASIC. Primary and optional secondary keys may be numeric or one to nine character strings.SORTIT is easily used with files generated by DYNACOMP's MAIL LIST program and is very versatile in us capabililies forall other BASIC data Tile sorting.

PERSONAL FINANCE SYSTEM (Alari and North Slar only)

Price: 134.95 DUhMt*

PFS is

nted l;

single diskette,deductible items, PI'S udefined codes by month or by payee. PFS will espackage requires only one disk drive, minimal mland over 1000 records per disk by making a few

ihat y

ii linalh

e where your money goes and (i

npotcd of ten diffcreni programs. Besides recording your expenses and laxicnscs by payee, and display information on expenditures by any of 26 useri produce monthly bar graphs of your expenses by category! This powerfulTiory (24K Atari, 32K North Star) and will store up to 60(1 records per disknple changes to the programs). You can record checks plus cash expenses so

irk and tcdio

! hand c

culaiio

FAMILY BUDGET (Apple onlv)FAMILY BUDGET is a very conveexpenditures as well as income onBUDGET also provides a continuoidifferent expense

r an o:hcrwise complicated (and unorganized!) subjec

lent financial record-keeping program. You sdaily basis. You can record tax deductiblerecord ofall credit transactions. You can malto 5 payroll and tax accounts. Data are easil;

Price: S34.95 Dfafctttt

II be able to keep track of cash and creditems and charitable donations. FAMI1 Ydaily cash and charge enirics to any of 21retrieved giving the user complete conirol

Price: W9.95 Dlsketlr

INTEUNK (Atari only)

This software package contains a menu-driven collection of programs for facililaling efficient two-waythrough a full duplex modem (required for use). In one mode of opcralion you may connect to a data service (e.g., TheSOURCE or MicroNct) and quickly load data such U stock quotations onto your diskette for later viewing. This greatly re-duces "connect time" and thus the service charge. You may also record the complete contents of a communications session.Additional!;, programs written in BASIC. FORTRAN, clc. may be built off-line using the support le.xt editor and later "up-loaded" to another computer, making the Atari a *tty smart lerminal. Even Atari BASIC programs may be uploaded.Further, a command file may be buill off-line and used later as controlling input for a time-share system. That is. you can setup your sequence of time-share commands and programs, and the Atari will transmit them as needed; batch processing. Allthis adds up to saving both connect time and your time.

TEXT EDITOR II <CP/M) Price: $29.93 Diskette S3J.45 Disk

This is the second release version of DYNACOMP's popular TEXT EDITOR I and contains many new features. Willi TEXTEDITOR II sou may build text files in chunks and assemble them for later display. Blocks of text may be appended, inserted ordeleted Files may be saved on disk'diskette in right justified/centered formal lo be later primed by either TEXT EDITOR IIor iheCP'M ED facility. Futlicr, ASCII CP/M Tiles (including BASIC and assembly language programs) may be read by theedilorand processed. In facl. (ex! files can be built using ED and later Tormaiicd using TEXT EDITOR II. All in all. TEXTEDITOR II is an inexpensive, easy lo use. but very flexible editing system.

Price: S 19.95

o maintain a specialized data base of ail files and programs in theto set up and use. It will organize your disks to provide efficienl

mill- (Atari and North Star diskettes only)

This handy program allows North Star and Alan disk uslack of disks which invariably accumulates. DULE islocating of ihc desitcd file or program.

F1NDIT (North Star only) Price: SIMS

This is a three-in-onc program which maintains in formalism accessible by keywords of Ihree types: Personal (eg: last name).Commercial (eg: plumbers) and Reference (eg: magazine articles, record albums, etc). In addition lo keyword searches, tlicrearc birthday, anniversary and appointment searches for the personal records and appointment seaiches for the commercial re-cords. Reference records are accessed hy a single keyword or hy cross-referencing two or Ihree keywords.

SHOPPING LIST (Atari and North Star only) Pri«:SL2.95Ca.u*n* S16.95 Diskette

SHOPPING LIST stores information on iiems you purchase at the supermarket. Before going shopping, n will remind you ofall the things you might need, and then display (or optionally print) your shopping lisi and [he total cost Adding, deleting,changing and storing daia is very easy Runs with I6K.

TAX OPTIMIZER (North Star only) Price: 589.99 Diskette

The TAX OPTIMIZER is an easy-to-use. menu oriented software package which provides a convenient means for analyzingvarious income tax strategics The program is designed lo provide a quick and easy data entry, ln:omc tax is computed by alltax methods (regular, income averaging, maximum and alternate minimum tax). The user may immediately observe ihe taxeffect of critical financial decisions. TAX OPTIMIZER has been ihoroughly field tesied in CPA olfices and comes completewith the current tax tables in its data files.

EDUCATION

HODGE PODGE (Apple only. 4oK Applesoft or Integer BASIC) Price: S19.9S Casjciie/SZ3.95 Diskette

Lei HODGE PODGE be your child's baby sitier. Pressing any key on your Apple will result in a diffcreni and intriguing "hap-pening" rclaicd to ihe letter or number of the chosen key. The program's graphics, color and sound are a delight for childrenfrom ages lilo9. HODGE PODGE is a non-iniimdaiing teaching device which brings a new dimension lo the use of com-

educs

TEACHER'S PET I (Available for all computers) Price: $11.95 Caueite 515.95 Diskette

This is lie first of DYNACOMP's educational packages. Primarily intended for pre-school to grade 3. TEACHER'S PETprovides the young student with counting practice, leiier-word recognition and three levels of math skill exercises.

MISCELLANEOUS

CRYSTALS (Alari only)

A unique algorithm randomly produces fascinating graphics displ;buill. Nolwo patterns are Ihe same, and the combined effect of (heused in local stores to demonsiratc the sound and color features c

NORTH STAR SOFTWARE EXCHANGE (NSSE) LIBRARY

DYNACOMP now distributes ihe 23 volume NSSE library These diskettes eatstanding value for the purchase price. They should be pari of escrs North Slar ilor details regarding ihc contents ol Ihe NSSE collection

Prtce:S 9.95Cauelle/*l3.95Dlikellr

s accompanied wiih lones wiich vary as ihc paderns aieiund and graphics arc mesmerizing. CRYSTALS has been

AVAILABILITY

DYNACOMP software is supplied sspecified, all programs will run wuhuable on ATARI. PET, TRS-60lLevidensity compatible) diskette Additicsystems running under MBAStC

.th complete documentation containing clear explanations and examples. Unless otherwise16K program memory space (ATARI requires 24K) Except where n cited, programs arc aval I -II) and Apple (Applesoft) cassette and diskette as well as Nonh Star single density (doublelally, mosi programs can be obtained on standard (IBM format) K" CPj M floppy disks for

STATISTICS and ENGINEERING

DIGITAL 1 III I It (Available for all computers) Price: SJ9.95 CuMtle/S-M.95 Diskette

DIGITAL FILTER is a comprehensive data processing program which permits ihe user 10 design his own filler funclion oichoose from a menu of filler forms. The filler forms are subsequently convened into non-recursive convolution coefficientswhich permil rapid dam processing. In (he explicit design mode the shape of (he frequency transfer function is specified bydirectly enlcring points along ihc desired filler curve. In Ihc menu mode, ideal low pass, high pass and bandpass filters may beapproximated to varying degrees according to Ihe number of points used in (he calculation. These fillers may optionally also besmoothed wilh a Manning function In addition, multi-stage Bullerworth fillers may be selected. Futures of DIGITALFILTER include plotting of the d.it.i before and after filtering, as well as display of tilt chosen Tiller Functions. Also includedarc convenient data slotagc, retrieval and editing procedures.

DATA SMOOTHER (Not available for Atari) Price: $19.95 Cusrite/SU.95 Dhknie

This special data smoothing program may be used lo rapidly derive useful information from noisy business and engineeringdaia which arc equally spaced. The software features choice in degree and range of fit. as well as smoothed First and secondderivative calculation. Also included is automatic plotting of the input daia and smoothed res tills.

FOURIER ANALYZER (Available for all computers) Price: $19.95 CUMtttTStt.M Mhtttc

Use this program to examine ihe frequency spectra of limited duration signals. The program features automatic scaling andplotting of the input data and results, ['radical applications include Ihe analysis of complicated patterns in such fields as clcc-

Pricei $19.95 Cu*elle/$13.95 Dliketlr

uate the transfer (unctions of systems such as hi-fi amplifiers and, majOI modification of FOURIER ANALYZER and contains anI as data editing features. Whereas FOURIER ANALYZER is dc-

TFA (Transfer Function Analyzer)

This is a special software package which may be used lo evi

filters by examining their response to pulsed inputs. TEA iscnginccriiig-orienicd decibel versus log-frequency plot as wi

led for educational and s

Itlfic U

. TEA fa

mi engineering It

. Available for a

nillipilU-

HARMONIC ANALYZER (Available for all computers) Price: $24.95 CuMiie/SU.93 Diskette

HARMONIC ANALYZER was designed for ihe spectrum analysis of repetitive waveforms. Features include data file genera-tion, editing and sloragc/rclricvul us well as data and spccirunl plaiting. One particularly unique facility is that the input dataneed not he equally spaced or in order. The original data is sorted and a cubic spline interpolation is used to creaic the data filerequired by (he FFT algorithm.

combined price of S49.9J

REGRESSION 1 (Available for all computers) Price: $19.95 Ca.iMltr/SZJ.93 Diskette

REGRESSION I is a unique and exceptionally versatile one-dimensional least squares "polynomial" curve fitting program.Features include very high accuracy: an automatic degree determination option: an extensive internal library of filling func-tions; daia editing; automatic data and curve plotting; a .statistical analysis leg: standaid dcvialion. correlation coefficient,etc.) and much more. In addition, new fils may be tried wilhoul reentering the data. REGRESSION I is certainly Ihe cornerstone program in any daia analysis software library.

REGRESSION II (PARAFIT) (Available for all computers) Price: $19.95 Cwwitr S2.1.95 DWntte

I'ARAFl T is designed to handle (hose cuses in which ihe parameters are imbedded (possibly nonlineailyl in the filling func-tion. The user simply mscrls (he functional form, including (he parameters IA(I), A(2), etc.) as one or more BASIC statementlines. Data and results may be manipulated and plotted as with REGRESSION I. Use REGRESSION 1 for polynomial filling,and PARAFIT for those complicated functions.

MULTILINEAR REGRESSION (MLR) (Available for all computers)

MLR is a prolcssional software package for analyzing daia scis containing twoperforming ihc basic regression calculation, (his program also provides easy tfunctions. In addition, ihe user may inierrogatc the solution by supplying valuevariables and data sire is limited only by (he available memory.

Price: $24.95 Cassette/SIB. 95 Diskette

r more linearly independent variahles. Beside,use data entry, storage, retrieval and editingfor ihe independent variables. The number of

r for SS1.9J (three ca»«t«3) or id).9*

ANOVA (Available for all computers) Price: $39.95 C ts«ltr<SJ3.95 Dltknit

In ihe past the ANOVA (analysis of variance) procedure has been limited lo the large mainframe computer*. NowDYNACOMP has brought the power of this method lo small systems. For those conversant wuh ANOVA. ihc DYNACOMPsoftware package includes Ihc I-way, 2-way and N-way procedures. Also provided are the Yales J*1* factorial designs. For(hose unfamiliar with ANOVA, do noi worry. The accompanying documentation was wrillen in a tutorial fashion (by a pro-fessor in ihc subject) and serves as an excellent Introduction lo the subject. Accompanying ANOVA is a support program forbuilding Ihe data base. Included are several convenient features including data editing, deleting and appending.

BASIC SCIENTIFIC SUBROUTINES. Yolume I (Not available for Alari)

DYNACOMP is (he exclusive distributor for the software keyed lo ihc popular Icxt BASIC Scientific Subroutines, I'alumv Iby F. Ruckdeschcl (see Ihc BYTE/McGraw-Hill advertisement in UYTE migaiine, January 1981). These subroutines havebeen assembled according lo chapter. Included with each collection is a menu program which selccls and demonsirates each

Collection ft: Chapter) 2 and J: Daia and function plotting, complex variablesCollection Wl: Chapicr 4: Matrix and vector operations

Collection M: Chapters 5 and fi: Random number generators, scries approximationsPrice per collection: 114.9* Casserie/Slfl.95 Diskette

All three collections arc available fOI $39.95 (ihree cassetics) and $49.95 {three diskettes).

Because the text is a vital pari of the documentation, BASIC Scientific Subroutines, Volume th available from DYNACOMP

for $19.9.1 plus 75C postage and handling. Sec review in Dr. Dobbs.

ROOTS (Available for all computers)

In a nutshell. ROOTS simultaneously deicrmines all ihe zercihc degree of the polynomial, and hecause (he procedure is Heratrequired as input, and the calculated roots arc substituted hack

Price $10.95 CwwlK SU.95 Dlskrltr

of a polynomial having real coefficients. There is no limit onlive, (he accuracy is generally very good. No initial guesses arei Ihe polynomial and ihc residuals displayed.

ACTIVE CIRCUIT ANALYSIS <ACAP) (48K Apple only) Price: $25.95 CtWMliaV$29.95 Dlsknie

ACAP is the analog circuil designer's answer lo LOGIC SIMULATOR. Wuh ACAP you may analyze ihe response of an ac-tive or passive component circuit (e.g.. a Iransislor amplifier, band pass filler, etc.). The circuit may be probed ai equal steps infrequency, and (he resulting complex (i.e.. real and imaginary 1 soilages at each component juncture examined. By plotting themagnitude of these voltages, ihc frequency response of a filler or amplifier may be completely determined wuh respect to holhamplitude and phase. In addition, ACAP prints a statistical analysis of the range of voltage responses which result fromtolerance variations in Ihe components. ACAP is easy lo learn and use. Simply describe the circuit in terms of the elements andtheir placemen!, and execute. Circuit descriptions may be saved onto cassette or diskette to be recalled at a later time for execu-tion or editing. ACAP should be purl ol every circuil designer's program library.

I.OGICS1MU1.ATOR (Apple onl>;48K RAM) Price: $24.95 Cm«elie/S2».95 Wikeiic

With LOGIC SIMULATOR you may easily lesl your complicated digital logic design wuh respect lo given set of inputs todetermine how well ihc circuit will operate. The elements which may be simulated include muliiple input AND. OR. NOR,EXOR. EXNOR and NAND gates, as well as inverters, J-K and I) flip-flops, and one-shois. The response of ihc sysiem isavailable every clock cycle. Inputs may be clocked in with varying clock cycle lengths/displacements and delays may be intro-duced io probe for glitches and race conditions. At ihc user's option, a liming diagram for any given sei of nodes may be plot-ted using HIRES graphics. Save your breadboarding until ihe circuil is checked by LOGIC SIMULATOR.

LOGIC DESIGNER (North Star and CP/M only) Price SJe.M Dttfttc

LOGIC DESIGNER is an exceptional Computer Aided Design (CAD) progiam. Wuh it you may conven a large and compli-cated digilial truth tabic (Ihc functional specification) into an optimized Boolean logic equation This equation may then beeasily convened inio a circuil design using either NAND or AND/OR gales. Operationally. LOGIC DESIGNER is composed

of a BASIC program which calls in a machine language routine io reduce execution lime. Example: For a 1 variable by 12" lineiable, (he processing lime is only two minules. LOGIC DESIGNER is clearly a fasi and powerful tool for building digital cir-

ORDERING INFORMATION

All orders arc processed and shipped wuhin 4H hours. Please enformation. If paying by VISA or Masier Card, include all nui

Shipping and Handling Charges

Wiihm North America: Add $1.50

Outside Norlh America; Add IU°'o (Air Mail)

ith order and include (he apptoprtate computer ir

DaUnn

All orders (excluding books!

Quantity DLxcuunu

8" CP/M Dliks

Add 12.50 lo Ihc listed diskette price for

Microsoft MBAStC or BASIC 80.

programs Dealerh H" floppy

arc available upon requesiland CP'M format). Programs

l H" CP/M disks is also available o

'.<" disks. North Star format,e for detailed descriptions of th

ind olher programs from

DYNACOMP, Inc.

1427 Monroe AvenueRochester, New York 14618

24 hour order phone: (716)586-7579 recordingOffice phone (9AM-5PM EST): (716)442-8960

New York Slalr rcildtnls plt.M idd 7«o NY'S .air. la*.

Circle 135 on inquiry card.

Clubs and Newsletters

Newsletter for Hamsand Computerlsts

Dits & Bits, The WSY1Report, is published twice amonth for the ham radiooperator and microcomputeruser. Articles on memory,FCC regulations, and otherrelated topics are included.Contact the newsletter atPOB 10101, Dallas TX 75207,(214) 690-1063.

Interested In aCentral Bulletin-Board Service?

Michael Witt is interestedin hearing from people whowould like to develop a com-puter network in which thecentral system would placecalls during the evening hoursfor reduced telephone rates.The system would be similarto other bulletin-board sys-tems, except messages wouldbe delivered and picked upby the central system insteadof users calling in.

Contact Michael Witt,POB 55686, Valancia CA91355.

Newsletteron Genealogy

Genealogical Computing isa bimonthly newsletter onpersonal-computer applica-tions involving genealogy.Contact Sara Andereck, c/oData Transfer Associates,5102 Pommeroy Dr, FairfaxVA 22032, (703) 978-8490.

SwissComputer Club

Founded in 1978, theSchweizer Computer Clubalready has more than 4000members. Members ownPET, Apple, Sorcerer, andother systems, and have aspecial CP/M group. The

club publishes three newslet-ters: Mikro- und Kleincom-puter, a bimonthly; CBM/PET News; and Computer-journal. Contact Ernst Erb,Schweizer Computer Club,Seeburgstrasse 18, CH-6002Luzern, Switzerland.

Free GraphicsNewsletter

Subscriptions to theDynamic Blackboard News,are free. The News featurescustomer applications, newproducts, technical notes,software news, and hints forgraphics users. DynamicBlackboard News is a publi-cation of the Cambridge De-velopment Laboratory. Con-tact Jean L Graef, CambridgeDevelopment Laboratory, 36Pleasant St, Watertown MA02172, (617) 926-0869.

Newsletteron Graphics

Computer Graphics Newsis published by the NationalComputer Graphics Associa-tion in cooperation withScherago Associates Inc. Thetabloid serves as a newssource for the computer-graphics community. For fur-ther information, contactScherago Associates Inc,1515 Broadway, New YorkNY 10036, (212) 730-1050.

Heath UsersGroup In California

Covering Riverside, SanBernardino, and West LosAngeles counties in SouthernCalifornia, the Tri-CountyHeath Users Group welcomesmembers and visitors to itsbimonthly meetings. Meet-ings are held the first Satur-day of each month at theHeathkit Electronic Center

1555 N Orange Grove, inPomona, and on the thirdSaturday of each month atthe University of Califor-nia-Riverside, Rm 1111,Watkins Facility. Meetingsbegin at 2 PM.

CP/M Users Group

The Sacramento Micro-computer Users Group is aCP/M users group that pub-lishes a monthly newslettercalled Push & Pop. Contactthe group at POB 161513,Sacramento CA 95816, (916)363-3962.

PocatelloMicrocomputer Club

Members of the PocatelloMicrocomputer Club usemost of the popular com-puters on the market today.Anyone interested in com-puters is welcome to join.Contact the club at POB8106, Pocatello ID 83209,(208) 232-4462.

PETs In Canada

The Toronto PET UsersGroup (TPUG) has a disk li-brary available for membersand nonmembers. The li-brary has approximately1400 programs provided byTPUG members and fromother clubs. Membership isencouraged even if you livetoo far away to attend meet-ings. Contact TPUG, c/oChris Bennett, 381 LawrenceAve West, Toronto, Ontario,M5M 1B9, Canada, (416)783-1645.

Science Networkand Newsletter

The COGNET Newsletterseeks to disseminate informa-tion on cognitive simulation,

computational linguistics,and artificial intelligence. TheCenter for Cognitive Scienceis also working on a comput-er network for those involvedin these areas of research. Fordetails, contact COGNET,Center for Cognitive Science,POB 1911, Brown Universi-ty, Providence RI 02912.■

BYTE's Bits

Industry's Eyes onNew LISP Computer

LMI has been granted alicense from the Artificial In-telligence Laboratory of MIT(Massachusetts Institute ofTechnology) to construct andcommercially market theMIT CADR machine. Thissystem is specifically de-signed as a programmer en-vironment for LISP. Accord-ing to an LMI spokesman,most LISP programs are de-veloped on the DEC (DigitalEquipment Corporation)PDP-10 mainframes, but theLMI system, although in theformat of a personal com-puter, provides up to sixty-four times the virtual addressspace. The base price of theLMI machine is $80,000.

Until recently, LISP usagehas been associated with re-search conducted at educa-tional institutions. But nowthat Control Data Corpora-tion and Texas Instrumentshave ordered LMI machines,LISP's commerical usage willbe seen in expert systems,VLSI (very large-scale inte-grated) circuit design, andnatural-language processing.

LMI is headquartered inLos Angeles, Calif ornia.H

332 October 1981 © BYTE Publications Inc

Our newest developmentIN THE continuing expansion of the

UCSD p-SYSTEM™ SOFTWARE. VERSION IV"

JOHN BRACKETT, President, SofTech Microsystems

Backed by a dedicated team ofprofessionals, SofTech Micro-systems continues to enhancethe world's most widely-used, portablesoftware development system. Todayit's the UCSD p-System, Version IV.Able to run on most majormicroprocessors including 8086, Z-80,8080, 8085, 6502, 6809, 9900 andLSI-11™, Version IV is the developer'stool to make perfect programs morepossible. It consolidates all the best fea-tures of earlier versions, while allowingfor much larger applications, concurrentprocessing and improved debugging.With the addition of BASIC, more macrocross-assemblers, and improved docu-mentation, Version IV is truly a total,professional software developmentand execution environment.

And, it's backed by SofTechMicrosystems, the first to deliver acomplete, portable software system formost major microprocessors with UCSDPascal™, FORTRAN-77, BASIC, andmultiple assemblers.

For tomorrow, the expansioncontinues. More 16 bit microprocessorinstallations. The performance impactof native code generation. New systemutilities and languages. New tools forcreating applications more rapidly.The SofTech Microsystems team is atwork today to increase your optionsfor the future.

Get the software system that'sgoing places. Distribution licenses andsingle copies available. Write or call fordetails, so you can start going places, too.

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UCSD p-System and UCSD Pascal are trademarks of the Regents of the University of California.LSI-11 is a trademark of Digital Equipment Corp.

Circle 341 on inquiry card.

BYTE Oceober 1981

333

System Notes

A Closer Lookat the TRS-80 Color Computer

Woody BakerRte 11, Box 4780Lufkin TX 75901

People who have purchased the TRS-80 Color Com-puter know that Radio Shack is reluctant to disclosemuch information about the internal workings of its com-puters—preferring that all work requiring the opening ofthe outer case be performed by an authorized servicecenter. However, it is possible to find much of this infor-mation; a bit of digging, a few phone calls to Fort Worth,and a disassembler from the Micro Works of Del Mar,California, enabled me to obtain the informationpresented here.

The TRS-80 Color Computer is based on the Motorola6809E microprocessor. [The "E" indicates the series—inthis case, the 6809 model capable of multiprocessing,although this capability is not used in the TRS-80 ColorComputer....SM] The unit uses a Motorola 6847 video-display-generator IC (integrated circuit) for the colordisplay—meaning there are a number of memory loca-tions within the computer that control which of theeleven modes the IC is in. If you know these locations,you can access the modes not provided by Radio Shack'ssoftware.

Memory Organization

The TRS-80 Color Computer uses page 0 (memorylocations decimal 0000 through 0256) as a scratch pad.The Motorola 680X microprocessors all have the abilityto use a special mode of addressing called direct page (thesame as the 6502 zero page mode). The enhancement add-ed to the 6809 is the ability to select which 256-byte pageto treat as page 0. In order for the 6809 to maintain680X-family compatibility, the default remains page 0.Microsoft followed this default in its BASIC interpreterwritten for the Color Computer—leaving most of the im-portant memory locations within page 0.

Since Microsoft uses the same conventions in all itsBASIC interpreters, it can be concluded that the BASICin the Color Computer is organized in a manner similarto its BASIC for 6502-based computers. The pointersto the start and end of BASIC and the start and end ofvariables are the same. Also, the storage format is thesame for BASIC lines (a 2-byte pointer to the start of theline, followed by a 2-byte line number, and then thetoken code terminated by a zero).

The Video Window

As shown in tables 1 through 4, the TRS-80 Color

Computer allows a surprising degree of control to theprogrammer. The video window is unique in that it canbe moved around within available memory, which in thiscase is from 0000 through 7FFF. You can set it to location

0 and watch the scratch-pad locations change as the com-puter is running. This is where the information sum-marized in table 4 comes from. In order to set the videomemory to page 0, just POKE any value into decimallocation 65480. When the POKE is executed, it clears bit

1 of the 7-bit binary word contained in the Motorola 6883SAM (synchronous address multiplexer) that controls thebase location of the video screen. To restore the videowindow to its normal location, POKE any value intolocation 65481—resetting bit 1.

The 6 bytes referred to in table 1 control the memory-mapping mode of the 6847 VDG (video displaygenerator). The 6883 SAM IC maps memory into thevideo circuits and can be thought of as a 3-bit numberthat selects the amount of memory available to the VDG.This 3-bit register is controlled by the locations shown intable 1. The desired result can again be obtained byPOKEing any values into these locations—toggling 3 bitsinto the SAM circuit. The VDG control lines are locatedin port 65314 and select the mode of the VDG. In order toswitch the Color Computer into another graphics mode,you first set the available memory to match the mode,and then select the mode via the port. It's necessary toturn the control lines on at the port and also set the videomemory size via the locations shown in table 2.

Table 2 shows the locations that control the base pageof the video memory. In order to locate the base page, theTRS-80 Color Computer hardware takes the 7-bit wordthese 14 bytes specify and multiplies it by 512—resultingin the location of the base page.

Locations shown in table 3 are either used by the 6809for interrupts or are assigned other functions by RadioShack. Although I was told their names by a Radio Shackrepresentative, I didn't find out their exact functions. Ap-parently, you can select four different clock speeds usingthese locations. Although I encourage you to experimentwith them, it's easy to lose your video-sync signal whenfooling with these locations.

Programmable-memory locations are shown in table 4.The keyboard buffer is terminated by a 0, and aPEEK(732) returns the token for the first keyword found

334 October 1981 © BYTE Publications Inc

TM

When Eight Is Not Enough:CP/M-86 "and CBASIC/86

"In 1977 Compiler Systems, Inc. introduced CBASIC" asa CP/M® programming language. It quickly became the mostwidely used BASIC dialect. Since then CBASIC has beenadapted for use on systems supporting MP/M™ andTRSDOS."

"At Compiler Systems we learned the lessonsof the past well. So well, that in the relatively shorttime we've been in the software business, we man-aged to make history ourselves. In fact, CBASICis the standard for CP/M-based business systems."

— Gordon Eubanks, CSI president

Today CSI offers CBASIC/86designed for 16-bit microcomputer-basedsystems running under CP/M-86.CBASIC/86, now available worldwide,is based on concepts first used byCBASIC including such business-oriented features as: BCD arithmeticwith fourteen-digit precision; full for-mat control of printed reports; ran-dom and sequential records of anylength (not limited to 256 bytes);aids to structured design, i.e. multi-ple line functions and control struc-tures as well as excellent file-handling and stringing capabilities.

But perhaps the best ofCBASIC/86 becomes clear whenyou're using it. To learn more about** CSI's commitment to support■** CBASIC/86 and CP/M-86 call1*4 (213) 355-1063 and discuss putting■j CBASIC/86 on your system.

Send this coupon today, we'll send details that go along way toward answering your questions.

Name/Date

Company

Address

City/State/Zip

OEMs contact us for pricing

□

0

Compiler Systems, Inc., 37 N. Auburn Ave., P.O. Box 145Sierra Madre, CA 91024, (213) 355-1063

WORLDWIDE DISTRIBUTION FROM

Circle 73 on inquiry card.

ATLANTIC COMPUTER

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Outstanding reliability and performance. These systems featurea Z80A CPU, S-100 bus, double density drives (either single ordouble sided), DMA disk controller, 64K RAM, 2 serial & 1 parallelport, and includes CP/Mr?Hard disk and multi user, softwareoptions.

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8000 Desk Top with dual, single sided 8" drives $4,775

MORROW DESIGNS - DECISION I $1,450

Decision I was designed to be the most versatile and cost effec-tive multi-user, multi-tasking microcomputer available today.Decision I CPU features a 4-6 MHZ Z80A, sophisticated memoryhardware, a real time clock and uNIX software. Floppy and Harddisk drives available.

ADD'S MULTI-VISION I $3,229

Features 64K RAM, MUON advanced operating system, up-gradable to multi-user, multi-tasking operations. Extensivesupport software and utilities available.

MUSYS SINGLE BOARD COMPUTER $1,295

Bootstrap PROM. Z 80 processor, 64K dynamic RAM, consoleserial port, S-100 parallel interface.

EPSON

MX-80 $ 499

MX-100 $ 775

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5510 (serial interface).. $2,749

5530 (parallel interface) $2,749

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Sprint 5/45 KSR $2,990

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DP 9500/9501 $1,299

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Systems **~*~-

in the line. In order to use this as an input routine, youwould need to preface each line with a REM state-ment—resulting in the first character after REM beinglocated at 733. The input routine uses the same buffer butdoesn't do any tokenizing. A flag may exist thatdisables the tokenizing routine. Once the keyboard-input

HexadecimalAddress

FFC0FFC1FFC2FFC3FFC4FFC5

DecimalAddress

654726547365474654756547665477

Function

Clear V0Set V0Clear V1Set V1Clear V2Set V2

Table 1: The six locations within the TRS-80 Color Com-puter's programmable memory that control the memory-mapping mode of the Motorola 6847 VDG (video displaygenerator). The graphics mode is selected via port 65314 andthe available memory must be set to match the'mode. Seelisting 1 for an example of a program that does this.

HexadecimalAddressFFC6FFC7FFC8FFC9FFCAFFCBFFCCFFCDFFCEFFCFFFD0FFD1FFD2FFD3FFD4FFD5

DecimalAddress65478654796548065481654826548365484654856548665487654886548965490654916549265493

FunctionClear bit 0Set bit 0Clear bit 1Set bit 1Clear bit 2Set bit 2Clear bit 3Set bit 3Clear bit 4Set bit 4Clear bit 5Set bit 5Clear bit 6Set bit 6Clear bit 7Set bit 7

Table 2: The TRS-80 Color Computer's programmable-memory locations that control the base-page location of thevideo memory. In order to calculate the base-page location,the hardware multiplies the resulting 7-bit number containedin the Motorola 6883 SAM (synchronous address multiplex-er) by 512.

Hexad

scimal

Decimal

Add

ess

Address

Function

FFD6

65494

Bank switch

FFD7

65495

Clear bit 2 elk rate

FFD8

65496

Set bit 2 c\k rate

FFD9

65497

Clear bit 1 elk rate

FFDA

65498

Set bit 1 elk rate

FFDB-FFDF

65499-65505

Memory size jumpers

FFF0-FFFF

65520-65535

6809 vectors

Table 3: A few miscellaneous control and interrupt locationswithin programmable memory. Hexadecimal locations FFD7through FFDA control the processor speed (nominally,0.894 MHz). Although experimentation is encouraged, theuser should be aware that these locations are tied to video-sync generation and may result in a temporary loss of video.

336 October 1981 © BYTE Publications Inc

Circle 427 on inquiry card.

A STANDARD FORPROFESSIONALS

HP-67 289.95

HP-97 584.95

HP-33C SCI... 79.95HP-34C SCI. . . . 114.95HP-38C BUS/RE 119.95

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System Notes,——^———

routine and the character-output routine are located,machine-language programming should be much easieron the Color Computer.

Applications

Since the video screen can be moved around inmemory via one of the registers in the SAM circuit, youcan use the information presented here to page throughmemory. If you are in the alphanumeric-graphics mode

Hexadecimal

Decimal

Address

Address

Function

19-1A

25-26

Pointer to start of BASIC

1B-1C

27-28

Pointer to end of program

1D-1E

29-30

Pointer to variables

1F-20

31-32

Pointer to start of arrays

88-89

136-137

Pointer to current cursor position

8C

140

Location of sound frequency

8E

142

Duration of sound

94

148

Cursor color

A8-AA

168-170

Jump vector to 43376

10C-10E

268-270

Jump vector to 43274

10F-111

271-273

Jump vector to 41046

112-114

274-276

Jump vector to 45974

11D-11F

285-287

Jump vector to 45509

2DD-3DC

733-988

Keyboard buffer

601

1535

Start of BASIC work space

Table 4: BASIC control and other miscellaneous locations

within page 0

of the TRS-80 Color Computer's program-

mable memory.

(the default), you can obtain an ASCII snapshot ofmemory. All the characters in the ASCII code range willshow up in the video display. Moving the window to theBASIC work space allows you to look at your BASICprogram. If you do this before doing a CLOAD, you canwatch memory filling up with a program. Since you canmove the screen back and forth, you can think of it as a"paging-mode" terminal. With the appropriate software,you should also be able to make a sophisticated screen-oriented editor. You cannot go above hexadecimal 7FFF,or page 64.

Putting the computer in the 64 by 64 color mode(listing 1) lets you use only half the screen. However,since you know where the starting pointers to BASIC are,you can change them and move the BASIC programdown in memory to allow you to use more memory forthe screen. This is accomplished by POKEing the new ad-dress into locations 19 through 1A hexadecimal or 25through 26 decimal, and then doing a NEW command byjumping to location AD19 (or 44313). Now you can useV0 through V2 to allocate more screen memory.

You can also go into other modes: POKEing a 240 intoport 65413 puts you into high-resolution mode, whichtakes 6 K bytes of programmable memory for the screen.In this mode, everywhere there is a "1" in memory, a litdot appears on the screen, and everywhere there is a "0"in memory, a black (unlit) dot appears on the screen.

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From preparing short letters to writing a book, word processing becomes easy and inex-pensive using VISI-WORD, a cassette based word processor. VISI-WORD is designed tointerface with just about any printer you can attach your Sorcerer to. VISI-WORD canaccept control characters, which allows you to issue special commands to thoseprinters with graphics controls, font control, and the like. A special feature of VISI-WORD, from which it gets its name, is the "command display off" feature. This com-mand eliminates all special end of line markers and other non-printing characters andautomatically performs right-justification, centering, and indenting right on the video,so that you can see what your text will look like before it is printed. Other features ofVISI-WORD include four separate buffers (to assist with form letters, boiler plating,and shifting text around), automatic page numbering and titling, partial print, andlocating strings. $59.95

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GBS is a general purpose programming system that can be used for many businessapplications. Use this system to create, edit, format, and print mailing lists. Or set up aninventory system, an accounts receivable file, or a payroll system. Or use it to enterorders. Delete, modify or append records, and then summarize and tabulate the results.You design (with the help of an extensively documented user manual) a system ofrecords. Then use the power of GBS to compute, sort, select, merge, add, and modifyyour data. GBS will provide you with the kind of fast, accurate, flexible tools you alwaysknew a home computer could provide. Four example application programs areincluded. Of course, you don't need to use GBS for business. You can use it for personalfinance, club or personal record keeping, or almost any type of problem that involvesthe management of records. Written in machine language with flexible cassette inter-facing, this program requires a Sorcerer with at least 32K of memory. $99.95

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System NotcsMM.^_»^...M

Listing 1: A program for the TRS-80 Color Computer dem-onstrates video-mode switching. This program sets the com-puter to a 64- by 64-character graphics mode. Each byte mapsinto four consecutive blocks on the screen, with a 2-bit codeused to indicate which of the four available colors (in this mode)each block will be. In this graphics mode, each horizontal line ofblocks is 16 characters wide, as opposed to 32 characters (bytes)wide in the normal mode of operation. Since this mode requires1 K bytes of programmable memory, with 512 bytes allocatedto the screen, you can only work with the upper half of thevideo display. See the text for further details.

5 POKE 65495,0:REM SPEED PROCESSOR UP10 BA = 1300:REM BASE OF THE CHARACTER15 POKE 65314,129:POKE 65473,0:REM SET COLOR

GRAPHICS MODE C20 FOR I = 1024 TO 1535:POKE I,0:NEXT I:REM PAINT 'A

SCREEN GREEN30 FOR I = 1 TO 8:REM 8 LINES PER CHARACTER40 FOR I = 1 TO 3:REM 3 BYTES PER LINE50 READ A:POKE BA + (I* 16) + I,A:REM PUT THE

CHARACTER DOWN60 NEXT J:NEXT I

70 GOTO 70:REM LOOP SO WE DON'T MESS DISPLAY UP80 DATA 0,255,0,3,255,192,15,60,240,15,255,240,15,225,24090 DATA 0,195,0,3,60,192,8,195,48100 END

A rather interesting location is 148 (hexadecimal 92).This location changes madly when you put video intopage 0. This is the so-called heartbeat of the system—thestorage location for the color byte that specifies the colorof the cursor. POKEing a 0 there makes the cursor goaway.

The 6809 machine-code interrupt vectors at hexa-decimal locations FFFO through FFFF all point to pro-grammable memory (except the reset vector). The resetvector points to cold-start BASIC. This routine is inROM (read-only memory), and has the responsibility ofresetting all other vectors and initializing memory. Itchecks if the machine has been on or has just been turnedon. If it has just been turned on, it initializes most of thescratch-pad locations. If you just hit a reset, it leaves cer-tain pointers alone, notably the pointers to your BASICprogram.

Conclusion

There is much more to be learned about the TRS-80Color Computer. I hope this article inspires you to godigging. I'd like to hear from people who discover otherinteresting facts about it. Hopefully, this information willgive you a good start toward understanding your newcomputer. ■

/Editor's Note: It's a little-known fact that Radio Shackpublishes technical service manuals for all its computerproducts. These manuals are available to the generalpublic and contain a wealth of "inside" information andtroubleshooting procedures. The manuals are not stockedby Radio Shack dealers. Contact your local Radio Shackstore for the price and ordering information. Also, see"What's Inside Radio Shack's Color Computer?" in theMarch 1981 BYTE, page 90....SM]

340 October 1981 © BYTE Publications lnc

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341

Book Reviews

Four Roads to UnderstandingRadio Shack's TRS-80

Yvon Kolya, POB 22, Peterborough NH 03458

PathwaysThroughthe ROM

George Blank, editorSoftside Publications6 South St, MilfordNH 03055, 1979, 1980116 pages, softcoverSI 9.95

Pathways Through theROM is actually a compila-tion of several manuals andarticles already availableseparately. They are:

• The TRS-80 DisassembledHandbook by RobertRichardson (the first ninechapters)

• SUPERMAP by RogerFuller (chapter 10)

• HEX-MEM Monitor, a pro-gram by John T Phillipp(chapter 11; originally pub-lished in the February issue ofPROG/80)

• Z80 Disassembler, a pro-gram by George Blank (chap-ter 12; originally published inthe June issue of PROG/80)

• DOS Map by John Hartford(chapter 13)

• "The WD1771 ControllerSpecification Bulletin" (chap-ter 14; available fromWestern Digital Corporation)

By collecting these worksin one volume, Softside Pub-lications has simplified theprogrammer's chore ofgathering information aboutLevel II DOS routines and

The four books reviewed here purport to give assem-bly-language programmers a key to the mysteries ofRadio Shack's TRS-80 Model I Level II ROM (read-onlymemory) and DOS (disk operating system). Because eachbook approaches the subject in a different way, it is diffi-cult to compare them all in the framework of a general dis-cussion, so I have considered them separately. At the con-clusion of each review, I have outlined the book'sstrengths and weaknesses as an aid to the prospective buyer.

has significantly reduced thecost (separately, these sixitems would cost over $34).

The first nine chapters(from The TRS-80 Disassem-bled Handbook) cover de-coding Level II ROM CALLlocations; integer-, single-,and double-precision arith-metic; four short demonstra-tion programs; ROM trig, ex-ponent, and log routines;miscellaneous ROM routines;an alphabetical list of ROMCALL addresses; two pro-grams—one in BASIC, theother in assembly code; and ashort self-test.

In the introduction to hisoriginal work, Robert Rich-ardson states that the hand-book came out of a series oflectures he gave. Unfortu-nately, the lectures were verygeneral; examples are in-cluded mainly in the demon-stration programs. It is ob-vious that Richardson feelsthe readers should do theirown experimentation, usinghis handbook as a beginning.He provides very little toguide you through the ROMbeyond pointing out the road

signs so that you won't gethopelessly lost.

The most valuable portionsof Richardson's handbookare the various tables in-cluded. For example, threeseparate figures list theBASIC functions with thelocations of their respectiveASCII (American StandardCode for Information Inter-change) representations inROM; the locations of theirCALL addresses (not thesame locations as the ASCIIcodes); the addresses them-selves in decimal form, inhexadecimal form, and inPOKE form (decimal low-order byte followed by high-order byte, ie: 174-29 insteadof 7598 decimal or 1DAEhexadecimal).

Chapter 10 is Roger Fuller'sSUPERMAP, a listing ofROM entry addresses andwhat the code at each addressdoes when accessed properly.Also provided is informationon the various cassette-tapestorage formats used by theROM. All in all, this is an in-formative and useful chapter.

Chapter 11 contains the in-

structions and listing of asimple BASIC monitor. Itssole purpose is to provideseveral memory-examiningcapabilities, if you don't al-ready have a monitor.

Chapter 12 is a 280 object-code disassembler. It's handy,too, if you don't already haveone.

Chapter 13, devoted tomapping TRSDOS andNEWDOS, is a valuable in-clusion. The two overlayregions used by the DOSesare defined, and the addressesand uses of the various DOSsystems are identified andlabeled. All of the RadioShack TRS-DOS system files(SYS0 to SYS6) are covered.Also given is the commandstructure necessary to callany of the DOS commandsfrom an assembly-languageprogram. This chapter andChapter 10 make PathwaysThrough the ROM wellworth the money, giving youinformation not availableanywhere else.

Chapter 14 is merely theWestern Digital FD1771-01floppy-disk formatter con-troller specification sheets (17pages). If you plan to write aprogram to access the diskdrives directly without usingany of the DOSes, these spec-ification sheets are a must.This is definitely not a begin-ner's project. The specifica-tions, written for expert as-sembly-language program-mers, include command flow-

342 October 1981 © BYTE Publications Inc

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The AMS 8000 Megabyrer System is for rhe serious user who wanrs roexpand rhe capability of his Apple* by increasing online dara storage,and reducing disk handling. It brings a new dimension to your Apple,making your dora portable ro other computers and gives you rhe re-liability associated with IBM standatd 8" floppy disks.

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BYTE October 1981

343

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charts, pin assignments, tim-ing specifications, informa-tion on formatting tracks,disk read and write opera-tions, and other technical in-formation.

The last section, the appen-dix, is very confusing. Thetable of contents calls it a"Reference Table of MemoryContents." What it actually isI don't know. It contains thefollowing:

• a decimal column goingfrom 0 to 255

• a hexadecimal columncounting from 0 to FF,matched to the decimal column

• a column labeled EXT,which makes sense only if it isrelated to the Z80 assembly-code mnemonics

• a column of the corre-sponding Z80 op codes,matched to the hexadecimalcolumn (which seems to sup-port the assumption aboutthe EXT column)

• a column labeled ASCII forthe numbers 0 through 127,which changes to GRAPHICfor the numbers 128 through191, and changes a last timeto TAB for the numbers 192through 255

• a column labeled TRS-80Controls for the numbers 0through 63, changing toTRS-80 BASIC for the num-bers 64 through 255.

None of these has anything todo with a table of memorycontents.

Conclusions

• Unfortunately, PathwaysThrough the ROM is only acompilation of the separateworks just discussed. No at-tempt has been made by theeditor to tie these differentitems together into a cohesivewhole. Each work uses a dif-ferent approach and differentwriting style. This makes themanual difficult to read andat times a frustrating ex-perience. It also means thatsome of the information isrepeated needlessly.

• As if this didn't make it dif-ficult enough, the manual it-self is poorly put together(and I don't mean physical-ly). There are numeroustypographical errors andmany outright editorial mis-takes, including figures withincorrect or no labels, andreferences to figures whichare not in the book. This ispossibly the result of its beinga hasty compilation ofseveral different works.

• Pathways Through theROM contains informationon the floppy-disk controllerand the DOS commands notpresent in the other ROMmanuals I have seen. Becauseof this, it might be of use tothe serious assembly-lan-guage programmer who has adisk system.

Inside Level II:A Programmer'sGuide to theTRS-80 ROM

John Blattner andBryan MumfordMumford MicroSystems, POB 435,Summerland CA 93067,1980, 65 pages,softcover, SI9.95

In their preface, the au-thors say the main objectiveof Inside Level II is "to pro-vide the information neces-sary for utilizing these rou-tines [stored in the ROM] inyour own assembly-languageprograms." This is quite ac-curately accomplished. Thesecond objective, which thebook doesn't achieve, is "todetail an efficient scheme forlinking assembly-languageand BASIC programs."

To realize the first objec-tive, the authors have se-lected the routines theybelieve will be of interest toassembly-language program-mers, and have carefully out-lined each step involved intheir use. Thus, not all theroutines in the ROM are ac-

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344 October 1981 © BYTE Publications Inc

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Book Review,

jyWvJETRONICSResearch&DevelopmentLtd.:I9l%333 Litchfield Road, New Millord, CT 06776 j

tually dealt with. For exam-ple, the AUTO, CLEAR, andEDIT commands are not evenmentioned.

For each routine, you aretold exactly what is beingdone, followed by the preciseprocedure in BASIC to getthe desired result. You arealso given warnings aboutwhat types of errors to ex-pect, both in Level II and diskBASIC, and what you can doto prevent them.

The book's introduction isshort (only three pages) andcovers how the TRS-80 repre-sents numbers, uses the regis-ters, and links to disk BASIC.

The rest of the book isdivided into three parts:

• the Level II ROM and re-served programmable mem-ory

• linking assembly-languageand BASIC programstogether

• appendices

Part I (chapters 1 through10) starts off by explainingexactly what each byte in re-served memory contains. Forexample, the bytes at hexa-decimal addresses 40AA to40AC hold the seed used bythe TRS-80 random-numbergenerator. This informationis followed by the entrypoints to Level II commandsand functions and the trans-fer points for disk BASICcommands. All this is inChapter 1.

Chapter 2 tackles registers,buffers, and the passing ofvariables from storage to buf-fers and back.

Chapter 3 concerns theconversion routines forchanging a numeric variablefrom one precision toanother, such as converting asingle-precision number todouble precision or to an in-teger, or a numeric string tobinary or vice versa. Ex-amples are given of short rou-tines that can be used to ac-cess the ROM properly fromyour own program.

Chapters 4 and 5 handlethe arithmetic operations andthe higher math functions(and even give the amount oftime required by the routinesto execute), while Chapter 6explains the keyboard input,from single-character to nu-meric to string input.

Chapters 7 through 10 dis-cuss the rest of the instruc-tions, cassette I/O (in-put/output), video display,VARPTR (which returns theaddress of a variable), andthe stack pointer.

Part II begins with Chapter11, which, according to itstitle, is about assemblers andmonitors. Actually, it merelysuggests you use an assemblersimilar to Radio Shack's ED-TASM and a monitor, prefer-ably the one sold by Mum-ford Micro Systems (publish-er of Inside Level II). Fortu-nately, this chapter is onlyone page long.

Chapter 12 gets down tothe technique of mixingBASIC and machine-lan-guage programs. Unfortu-nately, the methods discussedare somewhat awkward. Theauthors believe that machine-language routines of a mixedprogram should reside in lowmemory, and they go to agreat deal of trouble outlininghow this can be done, cover-ing CLOADing and CSAVE-ing techniques. Some of theadvice is common sense (i.e.,debug the machine-languageroutine before you combine itwith the BASIC program andvice versa). Because of thedifficulty of combining pro-grams in this style, I think theauthors have failed in theiravowed purpose. They didnot even consider the pros-pect of embedding the ma-chine-language routines inBASIC REM (remark) state-ments. This is easily done byloading your monitor abovethe BASIC program andreplacing the body of theREM statement with yourmachine-language routine.

346 October 1981 © BYTE Publications Inc

ATARI SOFTWARE

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Unfortunately, however, some companies and individuals have copiedATARI games in an attempt to reap undeserved profits from gamesthat they did not develop. ATARI must protect its investment so that wecan continue to invest in the development of new and better games.Accordingly, ATARI gives warning to both the intentional pirate and tothe individuals simply unaware of the copyright laws that ATARIregisters the audiovisual works associated with its games with the Libraryof Congress and considers its games proprietary. ATARI will protect itsrights by vigorously enforcing these copyrights and by taking the appro-priate action against unauthorized entities who reproduce or adaptsubstantial copies of ATARI games, regardless of what computer or otherapparatus is used in their performance.

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Book Review

Another important omis-sion was an explanation ofhow to make your program a"load-and-go" type, eliminat-ing the need to return toeither the system level or theBASIC level after your pro-gram loads.

The three appendices areonly two pages each. Thefirst is a simple hexadecimal-to-decimal conversion chart,while the second is a ma-

chine-language program forrecording a composite BASICand machine-language pro-gram on tape (but the com-posite program must be in theformat preferred by theauthors, with the machine-language routines "below"the BASIC program). Thelast appendix is the mostvaluable, giving a machine-language program that allowsfaster recording of DATA

tapes by shortening thelength of the leader and thesync byte.

Like the other books re-viewed here, it has no in-dex; however, the table ofcontents is detailed andmakes up for the lack of anindex.

Conclusions

• All of the steps required byBASIC when accessing the

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ROM from your own pro-gram are carefully outlined:what to do, when to do it,and where to do it.

• Part II is of use only to pro-grammers who do not writeprograms in pure machinelanguage and must use hybridprograms instead.

• My only complaint mightbe that the book is too con-cise, with explanations a littletoo short for the beginner.

• I recommend this book toserious machine-languageprogrammers.

The BOOK:Accessing theTRS-80 ROM

Raymond E Daly IV,Stephen C Hill, RoySoltoff, Thomas BStibolt Jr, and RichardP WilkesInsiders SoftwareConsultants, POB 2441,Springfield VA22152,1980, 123 pages,softcover, S14.95

According to the introduc-tion, The BOOK (volume I ofa three-volume set) is de-dicated to the math routinesof Level II BASIC. It claimsto be written for the novice tomachine-language program-ming, while not "talkingdown" to the expert. I mustsay that the authors certainlyhave achieved their objec-tives.

The first three chapters (32pages) deal with the formats,accumulators, and data man-ipulations for using the ROMmath routines, as well as theactual functions. In the firstchapter, you are given a lei-surely and thorough explana-tion of how the TRS-80 LevelII ROMs store and use mem-ory addresses, binary num-bers, and the memory accum-ulators. Numerous examplesare used to make these tech-niques as clear as possible.

The second chapter detailsthe ROM data-manipulation

348 October 1981 © BYTE Publications Inc

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Book Review,

techniques and routines, withexamples of how to movedata from the ROM workarea to your program's mem-ory area and how to use thedata-conversion routines(such as the ASCII string-to-binary number-conversionroutine).

Chapter 3 gives accurateand complete instructions oninterfacing the actual mathroutines to your own pro-gram. The authors have in-cluded a good deal of "extra"code in setting up their ex-amples. This approach is par-ticularly useful in illustrating

good programming tech-niques and makes it mucheasier for the novice to usethe routines immediately, butit makes it much harder tofind out what the bare re-quirements are to use a ROMroutine and to adapt the rou-tines more precisely to yourneeds.

Chapter 4 is not simply adisassembly of the math rou-tines of the ROM, but a com-pletely commented source-code listing with establishedlabels. This was probablydone by disassembling theROM and assigning labels

Start

End

Label Description

0B3D

0B58

INTSNG Take Integer of Single

0B59

0B9D

INTDBL Take Integer of DoubleTable 1

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and comments. This methodgives the byte number, a labelname (where applicable), theZ80 mnemonic (but not theextended mnemonics), and acomment field. It does notgive the actual op codesstored at those bytes. Thiswas probably an attempt toavoid infringement of Tandy(Radio Shack) and Microsoftcopyrights. (Because thisvolume is devoted to themath routines, only that por-tion of the disassembly deal-ing with those routines hasbeen reproduced in TheBOOK.)

This disassembly is fol-lowed by Appendix A con-taining the whole label tablefor the entire Level II ROM,not just those labels dealingwith the math routines. Theauthors say they did this toassist curious programmers infinding their way through theROM. Each label's start and,where applicable, end ad-dress are printed as shown intable 1.

Appendix B contains threelengthy examples of how touse the routines in actual pro-grams. Appendix C is a pro-gram listing of a disassemblerin BASIC.

Conclusions

• The BOOK, like InsideLevel II, is very thorough inits treatment of the math rou-tines, but unlike Inside LevelII, it gives numerous ex-amples and copious explana-tions. This is a real help forthe novice, and it also tendsto prevent the expert fromjumping to erroneous conclu-sions.

• Because of the use of labelsin the disassembly, it is veryeasy to see and understandhow the Level II ROMs ac-tually operate.

• The BOOK does not giveyou the locations and proce-dures needed by the ROM;rather, it provides short, sim-ple programs that use theROM routines. For the nov-

ice, this could be a handicapin learning how to use theroutines efficiently.

Microsoft BASIC

Decoded & Other

Mysteries

for the TRS-80

James FarvourIJG Computer Services1260 W Foothill Blvd,Upland CA 91786,1981, 310 pages,softcover, $29.95

Microsoft BASIC De-coded, the latest "ROMbook" on the market, is byfar the thickest and mostcomplete to date. It is the sec-ond volume on the TRS-80published by IJG ComputerServices, the first beingTRS-80 Disk & OtherMysteries.

Microsoft BASIC Decodedtakes a completely differenttack from the other booksdiscussed here: it attempts togive a total overview of theLevel II ROM operating sys-tem and Microsoft BASIC. Itstarts by explaining what ismeant by an operatingsystem, and what the TRS-80has by comparison with thisgeneral idea.

Next, the book takes youthrough the process of turn-ing on the TRS-80 computer,both with and without diskdrives attached. It also tellsyou how the BASIC inter-preter operates. Otherchapters explain the ROMsubroutines, cassette and diskI/O, addresses and tablesused, and disk BASIC mem-ory overlays.

Its best selling point, how-ever, is the inclusion of a dis-assembly of the entire TRS-80Model I Level II ROM set,both the old and the newones, from hexadecimal 0000all the way to hexadecimal302A, with almost every linecommented in plain Englishas to its purpose. The format

350

October 1981 © BYTE Publications Inc

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Book Review,

is very straightforward:

byte number — Z80 op code— mnemonic — comment

The mnemonics are restrictedsolely to the primary com-mands because the printing ofthe extended mnemonicswould probably be a viola-tion of the copyright laws.

In an effort to make itsimpler for you to use thisdisassembly, the book pageshave been predrilled to fit athree-ring binder and thebinding has been prepared foreasy removal of this section.This is a brilliant idea, and Iwonder why more publishersdon't do this; there are manybooks that I wish had beenmade in this way.

Not only does the loose-leaf binder make it easier towork with the pages, but italso makes it possible for youto insert your own pages ofcomments wherever youwant to. And that's not all:because most programmerswill want to include the ex-tended mnemonics in theirbinders, a simple scheme hasbeen devised to accommo-date this desire. Each page ofthe disassembly is a standard8V2- by 11-inch sheet of 66lines (four of the lines areblank, to provide spacing atthe top and the bottom). Thismeans that any printer cap-able of printing 66 lines per11-inch page will be able toproduce a disassembly tomatch the book pages per-fectly. The only qualificationis that you have to use a dis-assembler that automaticallypaginates after printing 62lines.

If you use the Apparat Dis-assembler, which is what theauthor used, you should havea perfect match to the book.This scheme is very wellthought out. The book's dis-assembly even goes so far asto note the errors of disas-sembly that most disassem-blers will make (i.e., the dis-

assembler doesn't knowwhen it is mistakenly decod-ing a table of addresses orASCII messages to the opera-tor).

All in all, the publisher andauthor have done a remark-ably efficient job of making itas easy as possible for you tohave a correct and completedisassembly of the TRS-80Model I Level II ROMs. Thisdisassembly is Chapter 8 ofthe book and occupies 246pages. It covers the entire oldROM set that Radio Shackoriginally sold (it displayedRADIO SHACK LEVEL IIBASIC when the machinewas turned on). Chapter 7(only three pages long) pointsout the few differences be-tween the old ROM set andthe new ROM set (whichdisplays R/S LII BASIC).Without a doubt, these twochapters alone would havemade a "best seller" in thepersonal-computer field.

As I mentioned before, thefirst six chapters are devotedto the gargantuan task of try-ing to tell you precisely howthe Level II ROMs work, andthey simply do not live up tothe standard set in the lasttwo chapters.

Chapter 1 contains the ex-planations of memory use,Level II operation, interpreta-tion, and execution; and, ingeneral, it provides a simpleoverview of just what it isthat the Level II ROMs do tocontrol the TRS-80 system.

The second chapter is atremendous letdown. It issupposed to be a guide to ac-cessing the different ROMsubroutines, but it is poorlywritten and incomplete. Theexplanations are not simple,and the format used is not ex-plained. There are no warn-ings as to possible problemsarising from the use of rou-tines; and the sample pro-grams don't tell you whatyou need to know to use theroutines.

Neither this chapter nor

any of the others explains themethod used by the ROMs tostore numbers, except to notethat integer numbers require2 bytes of memory, single-precision numbers need 4bytes, and double-precisionnumbers need 8 bytes. Tobalance this omission, theauthor has included a precisemathematical explanation ofthe formulas used by theROM to compute the func-tions of sine, cosine, tangent,arctangent, exponentiation,natural logarithm, andsquare root. This informationis not duplicated in any of theother books about the ROM.

Finally, not all of the sub-routines that should havebeen included have been in-cluded. For example, Chapter2 gives the routines used toturn on the cassette-drivemotor, how to read and writethe leader bytes, and how toread and write data. It doesnot tell you how to turn offthe cassette motor, althoughyou can find this informationin the disassembly of Chapter8 if you are patient.

Chapter 3, a considerableimprovement over Chapter 2,concerns cassette and diskI/O formats and timing andincludes timing diagrams forthe cassette data. The disksection gives the controllercommands—head seek, step,restore, etc. It goes into detailon the data formats on thedisk, covering the GAT(granule allocation table), theHIT (hash index table), thedisk DCBs (device-controlblocks), and the directorysectors. In fact, the onlyother book that goes intomore detail on the disk-dataformats is TRS-80 Disk &Other Mysteries.

Chapter 4 is devoted to allof the tables used by theLevel II ROMs and to lists ofaddresses of important rou-tines. In addition to the tableof Level II reserved wordsand their respective ROM ad-dresses, there are tables of the

hierarchy of arithmetic oper-ations, data-conversion rou-tines, and error codes. Othertables, which are built inmemory by BASIC for pro-gram execution, include theMode Table, the ProgramStatement Table, and theLiteral-String Pool (where thegarbage collection routinespends all of its time). Thischapter is crammed with in-formation, but it is writtenmore for the expert program-mer than for the novice.

Chapters 5 and 6 are exam-ple programs illustratingmethods of using the ROMroutines in your own pro-grams to do such things as in-itiate your own new BASICcommands and using theDOS overlay concept in aBASIC program to execute aprogram longer than theavailable memory (i.e., run a64 K-byte program in a ma-chine with only 32 K bytes ofmemory).

Conclusions

• This book is physicallyvery well designed for max-imum use by programmerswho want to understand theLevel II ROM and add to theinformation provided in thebook.

• The writing is uneven,sometimes clear enough forthe novice, sometimes not.

• Despite its flaws of omis-sion and the unevenness inthe first chapters, the disas-sembly and its design makethis one ROM book thateveryone should buy.B

352 October 1981 © BYTE Publications Inc

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Micro-Telegram™ lets your Apple II™ computer access Western Union™ services,worldwide. You can send Mailgrams.® Send and receive TWX,® Telex, and internationalcables. Receive Infomaster® up-to-the-minute news, stock, foreign exchange, gold,futures, sports, and ski reports. Use your Apple™ to wire money. To send flowers. Tocheck the snow at Sun Valley. To see what the Yen is selling for. To contact over 900,000TWX and Telex subscribers around the world.

And because it's more intelligent than a mechanical Teletype™ machine, Micro-Telegram lets you edit messages right on the screen, sends them automatically withoutyou in attendance, keeps subscriber directoriesand distribution lists, prints when you want itto, and asks you in plain English for yourcommands. Besides, it doesn't clatter andchurn out reams of paper.

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Circle 222 on inquiry card.

System Notes

Two Short Graphics Programsfor the OSI C-1P

John F Leahy

30345 Chualar Canyon Rd

Chualar CA 93925

Here are two pattern-producingvideo graphics programs for the OhioScientific Challenger IP microcom-puter. With one of these running insome conspicuous spot at your nextparty, you'll be amazed at the atten-tion it attracts.

Be careful, though. You or yourguests may go crazy trying to figureout the pattern, because the pseudo-random-number generator is used forboth displays.

You choose your own rise and de-cay times for the display elements.The parameters 1000 and 1500 aresuggested for starters. There'll be nodecay, however, if the decay time isset at less than the rise time.

To speed up the action, use a delaylimit of 500 or less. To slow it down,try 3000 or higher.

Happy viewing! ■

Listing 1: This OSI BASICdisplays fascinating randompatterns on your video display.

10 FOR X = 1 TO 30: ? : NEXT

20 INPUT"RISE TIME (1000?)"; E

30 INPUT"DECAY TIME (1500?)";

40 FOR X = 1 TO 30: ? : NEXT

50 C = INT (RND(1)*255)

60 D = 0

70 L = INT (RND(1)*920)

80 L = L + 53314

90 POKE L,C

100 D = D + 1

programgraphics

110 IFD > ETHENC =120 IF D = F GOTO 50130 GOTO 70

32

Listing 2: A variation of the display pro-gram in listing I,

10 FOR X

TO 30: ? : NEXT

20 INPUT"DECAY TIME (1500?)"; M

30

FOR X = 1 TO 30: ? : NEXT

40 I = INT (RND(1)*M)

50

C = INT (RND(1)*255)

60

L = INT (RND(1)*920)

70

L = L + 53314

80

POKE L,C

90

FOR T = 1 TO I: NEXT

10(

) POKE L,32

11C

GOTO 40

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"■',-' .;.«pHHMHKn

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Textwizard transforms Atari into apowerftdly serious word processor.

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Circle 414 on inquiry card.

"Atari is a registered trademark of Atari Computers Inc.

Programming Quickies

Memory Manipulator

Eliminate Hex-a-phobia

Louis P Witt Jr, 1302 41st St, Orlando FL 32805

Under Radio Shack Level II BASIC, you can storeshort machine-code subroutines in string variables. Thestrings cannot be loaded via cassette, however, becauseseveral ASCII (American Standard Code for InformationInterchange) codes will be interpreted as end charactersand cause a loss of data. Therefore, the only way to usethe strings as storage is to either POKE the code intomemory or list it in the program as DATA elements, bothof which require converting the data to decimal first.

Memory Manipulator is an attempt to solve that prob-lem and the hassles of translating characters to ASCIIcodes, or any combination of hexadecimal, ASCII, ordecimal conversion. It is an outgrowth of my intense dis-like for errors that are due to base conversions creeping inand destroying what could have been a good program.

Program Operation

Memory Manipulator (see listing 1) allows you to in-put data in either hexadecimal, ASCII, or decimal, storethe data at any location in programmable memory, andlist it in any of the three forms on a video display or a lineprinter. Each function of the program is essentially inde-pendent of the other; the only routines shared are thehexadecimal-to-decimal conversion section at line 5000and its reciprocal function at 6000. The remainder of thefunctions can be inserted or omitted as you see fit. Theprogram uses about 3600 bytes of memory; however, thiscan be greatly reduced by deleting remarks and usingmultiple-statement program lines. There are not toomany remarks, because the program is essentially self-explanatory. jext continued on page 362

Listing 1: Memory Manipulator program, written in RadioShack Level II BASIC. This program takes data input as ASCIIcharacters, decimal numbers, or hexadecimal numbers andplaces the hexadecimal equivalents into a specified area ofmemory. It also can read hexadecimal data from memory anddisplay it in any of the above forms.

102li304050607080909495:L0111212ME13141516161617181920101010

HEM MANIPULATOR

BY LOUIS P. WITT,JR.

THIS ROUTINE-POKES & PEEKS INHEX

DECIMALASCIIALLOWS ALL ADDRESSESCLEAR 50 0DEFSTR A-C

INPUT AS HEX

' MENU

CLS J PRINT CHR*(23)

PRINT: PRINT"MORY MANIPULATOR0 PRINT'1 HEX POKEHEX PEEKDEC POKEDEC PEEKASC POKEASC PEEK

PRINTtPRINT

INPUT"SELECTION"JN

ON N GOTO 1000,2000;

GOTO 120

RINT'POKE MEMORY

PRINT"2PRINT"3PRINT"4PRINT"5PRINT"6

000

0

001020

3000,400077000.8000

INPUT"START WITH"JX*GOSUB 50 00 'CURT TO DEC

Listing 1 continued on page 358

356 October 1981 © BYTE Publications Inc

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Paul Horowitz & Winfield Hill

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Confused by the other half of electronics? The Art of Electron-ics combines a comprehensive stand-alone treatment of bothanalog and digital electronic design, boot-strapping the readerthrough to an advanced level of design proficiency. This freshnon-mathematical view of electronics emphasizes circuit designand implementation, illustrated with hundreds of examplesstressing the tradeoffs involved in the choice of circuit configu-rations, device types, and component values. It provides aneasy entry into electronics for the inexperienced, yet its wealthof valuable insights and techniques makes it an ideal referencefor the computer hobbyist, specialist, or electronic engineer. $24.95

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Programming Quickies.

Listing 1 continued:

1030104010501060107010801085

10901095

11001110111111121113111420002010

20202030204020502060206520702080209021002110211521202125

213021402150216021702180213521872190220022102211221222132214300030103020303030403050306030653070

30803090309130923093309431004000

'START WITH N

N=X

X = N

GOSUB 6000' CURT TO HEX

PRINT"MEM=>"X$»

INPUTX*

GOSUB 5000' CVRT TO DEC

IF N>32767 THEN

N=-l*(65536-N)POKE N,X 'STOREIF N<0 THEN

N=65536+NN=N+1 'NEXT CELLGOTO 1040 'LOOP

READ MEMORYINPUT"1 FOR CRT

2 FOR PRINTER"5P

'END AT";X*5000 'CURT

N TO FI STEP 16

CURT TO HEX

INPUT'START AT'JX*

GOSUB 50 0 0 'CVRT TO

N=X

INPUT

GOSUB

CLS

FI=X

FORN

X=N

GOSUB 60 0 0

PRINT X$"=>"}

IFP=2THENLPRINTX*"=>

FOR M=0 TO 15

R=N+M : IF R>32767

THEN R=-lx(65536-R>X=PEEK(R)

GOSUB 6000 'CVRT TOX$=RISHT*(X*»2)PRINTX$»" "5IFP=2THEN LPRINTX$J"NEXT MPRINT

IF P=2 THEN LPRINT"NEXT NGOTO 120

DEC

TO DEC

HEX

PRINT"DECIMAL POKE MEMORY

INPUT"START ADDRESS"»X*

GOSUB 50 0 0 'CVRT DEC

N=X

X=N JGOSUB 60 0 0

PRINTX$;

INPUTJ

IF J>255 OR J<0 THEN 120

R=N : IF

R=-l*<65536

POKE R,J

N=N + 1

OR J<0 THEN i:RX32767 THENR)

GOTO 3040PRINT"DECIMAL

PEEK MEMORY

Listing 1 continued on page 360

358 October 1981 © BYTE Publications Inc

Circle 58 on inquiry card.

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BYTE October 1981

359

Circle 74 on inquiry card.

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BROAD BAND MICROWAVE

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With built-in-converter to channel2, 3, or 4 of any standard TV set.

RANGE: Line of sight to 250 miles.

SCOPE: Will receive within the frequency band from salelites. primarymicrowave stations, and repeater microwave boosterstations.

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This system is not a kit and requires no additional devices or equipment other thana TV set to place in operation DEALER INQUIRIES INVITED.

Programming Quickies,

Listing

1 continued:

4010

INPUT"1 FOR CRT

2 FOR PRINTER"»P

4020

INPUT"START ADDRESS"JX*

4030

GOSUB 50 0 0 'CURT DEC

4040

N=X

4050

INPUT"END ADDRESS"5 X*

4055

GOSUB 50 0 0

4057

CLS

4060

FI=X

4070

F0RN=N TO FI STEP 10

4080

X=N X GOSUB 6000

4090

PRINTX*°=>"

4100

IFP=2THENLPRINTX*"=>"♦

4110

FOR M=0 TO 10

4120

R=N+M tIF R>32767 THEN

R=-1>K(65536~R)

4130

PRINT USING " *** ">PEEK<R>»

4140

IFP=2 THEN LPRINT USING

' *** "5 PEEK(R)»

4150

NEXTM

41<60

PRINT

4170

IFP=2THENLPRINT" "

4180

NEXT N

4190

INPUTZ$!GOT0120

4200

4210

4211

4212

4213

4214

5000

'X=DEC VALUE OF X*(HEX)

5010

X = 0

5015

IF LEN<X$)=0 THEN 5120

5020

A1=LEFT*CX*»1)

5030

X1=ASC(A1)

5040

Xl=Xl-48

5050

IF Xl>9 THEN Xl=Xl-7

5060

IF XK0 OR Xl>15 THEN 120

5070

X=X*16+X1

5090

X$=RIGHT$<X*9LEN<X$)-1>

5100

GOTO 5015

5120

RETURN

5130

5140

5141

5142

6000

'X*=HEX VALUE OF X

6010

X$=""

6020

FOR 0=3 TO 0 STEP -1

6030

X1=FIX (X/16CQ)

6040

X=X-Xi*16CQ

6050

Xl=Xl+48

6060

IF Xl>57 THEN Xl=Xl+7

6070

X$=X$+CHR«(X1)

6080

NEXT Q

6090

RETURN

6091

1

6092

1

6093

1

6094 '

70 0 0 PRINT"ASCII POKE"

7010 INPUT-START ADDRESS"JX*

7020 GOSUB 5000

7030 N=X

7040 X=N

7050 GOSUB 6000

7060 PRINTX*"=>°;

7070 A=INKEY$:iFA=""THEN7070

Listing 1 continued on page 362

360 October 1981 © BYTE Publications Inc

Circle 394 on inquiry card.

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BYTE October 1981

361

Circle 71 on inquiry card.

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J odd War II rages across Europe..Castle Wolfenstein is occupied by trie armyof the Reich and converted into battle-frontheadquarters. You have been captured andbrought to the Castle for interrogation by thedreaded SS. From a hiding place behind thestones of the dungeon a dying cellmate pro-duces a Mauser M-98 pistol fully loaded withten bullets and gives it to you. Your newmission: Find the Nazi war plans and escapeCastle Wolfenstein alive.Castle Wolfenstein'" is an action adventuregame from MUSE demanding fast thinkingand quick manual response. Use game pad-

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^lijOLFENSTEIiNT

by Silas S.Warner

MUSE:

330 N CHARLES STREETBALTIMORE. MD 21201.(301)659-7212

Programming Quickies.

Listing 1 continued:

PRINTA

R=N t IF R>32767 THEN

R=-lx<65536-R>

POKE R»ASC(A)

N=N + 1

GOTO 7040

70757080

709071007110711171127113711480008010

802080308040805080608070808080908100811081208130

S1408150

816081708180819082008210-82208221822282238224

Text continued from page 356:

Under Level II BASIC, POKE and PEEK first converttheir operands to 2-byte signed integers, having a rangeof —32768 to +32767. Since memory locations can go ashigh as 65535, this range would be inadequate. The se-quence before the POKEs and PEEKs (such as line 1085 inlisting 1) works out the integer value that will properlyaddress the location you desire. If you're operating a16 K-byte (or less) machine, you can omit thesestatements.

There are no formal exits from the loops in the pro-gram sections, so an intentional error or the BREAK keymust be used. Usually this is bad practice, since rerunningthe program will lose variables or leave a job half done.In this case, it is acceptable because arguments are not be-ing passed from section to section.

Using the Program

Before you load this program, set aside some highmemory by means of the MEMORY SIZE? parameter;otherwise, you can destroy the program as soon as youPOKE anything into memory.

PRINT"ASCII PEEK MEMORYINPUT"1 FOR CRT

2 FOR PRINTER"5PINPUT" START ADDRESS" ', X*GOSUB 5000N=X

INPUT"ENDING ADDRESS"iX*GOSUB 5000FI=X

FOR N=N TO FI STEP 16X=N t GOSUB 6000PRINTX$"=>";

IF P=2 THEN LPRINTX$"=>";FORM=0 TO 15R=N+M : IF R>32767 THENR=-l*(65536-R)J=PEEK(R)

IF J<32 OR J>127 THENJ = 46

PRINT CHR$(J)5" "5IFP=2 THEN LPRINT CHR4(J)J;NEXT MPRINT

IFP=2THEN LPRINT" "NEXT N

inputz$:goto 120

END

362 October 1981 © BYTE Publications Inc

Circle 258 on inquiry card.

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Programming Quickies.

If you use the program to convert a short routine todecimal so that you can place the converted codes into adata statement of another program, load the system tapecontaining the data to be converted and use the decimalPEEK function in listing 1. All addresses are given andreturned in hexadecimal. If you want the addresses indecimal, replace the GOTO 5000 statements followingthe address input with:

N = VAL (X$)

section so that it only prints when the next 3 bytes con-tain the numeric codes for a CALL 0033 Z80 instruction.This approach won't be fast and you'll have a lot ofsearching to do, but it beats rewriting a routine that'salready in the machine.

This program was written with the intention of addingand changing the code as special situations arise, so makealterations freely.

Perhaps "hex-a-phobia" will be cured in short order! ■

Also, check inside the display loops for similar changes.

Memory Manipulator can be used to examine the con-tents of any section of memory. If you have a program inmemory that works (ie: you already spent a night de-bugging it), you can use the hexadecimal PEEK functionto get a hard copy of the code in memory. (See listing 2.)If you're ever searching for a particular routine in ROM(read-only memory), this function could be equally bene-ficial. To find the subroutine, insert a few lines into theprogram in listing 1 that will test the contents of the bytesit reads for the machine instruction you are looking for.

For example, if you want to find the routine in theLevel II BASIC ROM that converts values to strings fordisplay, change the print lines in the hexadecimal PEEK

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Listing 2: Sample outputs of the program in listing 1 showing thecontents of memory locations hexadecimal 4A00 to 4AFF. List-ing 2a shows the equivalent ASCII characters. Note that loca-tions which contain codes not associated with printable ASCIIcharacters are displayed as dots (.). Listings 2b and 2c show thedecimal and hexadecimal equivalents, respectively.

(2a)

iaoo=:

•= >

t

*

. J

, ,

,

M

,

0

,

4Aif)=;

1

) .

7

J .

. R

,

N .

M

•

t

4A20»:

R

3

2

7 6

7

,

,

4A30*=:

•R .

1

,

( 6

5 5

3

6 .

R

)

,

U

4A40»:

J ■

,

,

■

*

* t

i

t

4A50=!.

•< R

i

.

w J

, ,

4

P .

2

,

4A60 =

► ,

.

"

*

*

1

•

4A70=.

•i .

R

)

; ,

-> J

6

. ,

H

,

J

iabo=:

e .

,

,

J J

, ,

P

2

■

ia?o=;

•

J

T

, .

N

,

. J

t

.

z

iaao=:.

$ !

1

2

o .

. J

h

4abo=:

-J r

,

,

. J

5

.

iaco=:

-J t

4

, ,

. J

U

4AD0=!

J V

,

i ,

. J

,

, ;

X

=

iaeo=:

■D E (

y

A L

U E

0 F

X

*

(

1AF0=:

H E )

)

•

. J

• •

X

0

•

K

•

(2b)

1AD0=^

61

62

34

59

0

20

74

14

16

129

32

1A0A='.:

32

77 ;

13

48

32 189

32

49

4B

0

63

1A11=::

A3

74

24

16

82 213

78

205

77

32

58

ia:le=;

58 1

43

32

32

212

51

50

55

54

55

32

1A28=;

32 I

02

10

32

32

32

32

32

82

213

206

1A32=;

206

49 I

07

40

54

53

53

51

54

206

82

1A3C=;

82

41

0

85

74

34

16

178

32

191

32

9A16=;

32

34

32

35

35

35

32

34

59

229

40

1A50=;

10

82

41

59

0 119

74

44

16

143

80

1A5A=;

so :

13

50

32

202

32

175

32

191

10

32

4A64=0

32

32

32

32

32

34

32

35

35

35

32

1A6E<:

32

34

59

229

40

82

41

59

0

126

74

tA78=::

74

54

16

135

77

0

132

74

64

16

178

1AB2=;

178

0 146

74

74

16

143

80

r

13

50

202

4A8C=0

202 1

75

34

32

34

0

154

74

84

16

135

4A96=0

135

32

78

0

167

74

94

16

137

90

36

iaao=;

36

58 141

49

50

48

0

175

74

104

16

4AAA=C

16

58 147

251

0 183

74

114

16

58

147

iabi=;

147 I

51

0

191

74

15

16

58

147

251

0

1A6E=>

0 1

99

74

116

16

58

147

251

0

207

74

1AC8=;

74 1

17

16

58

147 251

0

215

74

118

16

1AD2=?

16

58 147

251

0 1

45

74

136

19

58

147

4ADC=;

147 I

51

88

61

68

69

67

32

86

65

76

1AE6=;

76

85

69

32

79

70

32

88

36

40

72

4AF0=I

72

69

88

41

0 253

74

146

19

88

213

(2c)

4A0C =

:-3D 3E

22 3B

DO

14 4A

0E 10

81

20 4D

D5

30

20

BD

1A10 =

-2 0 31

30 00

3F

4A 18

10 52

D5

4E CD

4D

20

3A

8F

4A20 =

S20 52

D4 33

32

37 36

37 20

CA

OA 20

20

20

20

20

1A30 =

:>52 D5

CE 31

CF

28 36

35 35

33

36 CE

52

29

00

55

4A40 =

>4A 22

10 B2

20

BF 20

22 20

23

23 23

20

2?

3E:

E5

1A50 =

>2B 52

29 3B

00

77 4A

2C 10

BF

50 D5

32

2 0

CA

20

4A60=

= AF 20

BF 0A

20

20 20

20 20

22

20 23

23

23

20

■in

4A70 =

:>3E E5

28 52

29

3B 0 0

7E 4A

36

10 87

4D

00

84

4A

1A80 =

:>40 10

B2 0 0

92

4A 4A

10 BF

50

D5 32

CA

AF

22

20

4A90 =

122 0 0

9A 4A

54

10 87

20 4E

00

A7 4A

5E

10

89

5A

'IAA0 =

= 24 3A

8D 31

32

30 00

AF 4A

68

10 3A

93

FB

00

B7

4AB0 =

>4A 72

10 3A

93

FB 0 0

BF 4A

73

10 3A

93

FB

00

C7

4AC0 =

•4A 74

10 3A

93

FB 0 0

CF 4A

75

10 3A

93

FB

00

07

4AD0^

■4A 76

10 3A

93

FB 0 0

F5 4A

88

13 3A

93

FB

58

3D

4AE0 =

'44 45

43 20

56

41 4C

55 45

20

4F 46

20

58

24

28

4AF0 =

>48 45

58 29

00

FD 4A

92 13

58

D5 30

00

12

4E

97

364 October 1981 © BYTE Publications Inc

Circle 153 on inquiry card.

UJlsUL

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After many years of extensive research and development comes LOGO, a powerfulnew programming language designed to put control of the microcomputer back intothe hands of the programmer. Now children and adults alike can embark on a voyageof self-discovery as they teach the computer to think (not vice versa). Working in theLOGO environment can inspire the programmer to "think about thinking" and, ineffect, become the architect of their own learning experience. Simply stated, LOGOrepresents a giant step forward in the world of microcomputer programming.

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Circle 203 on inquiry card.

BYTE October 1981

365

Technical Forum

Use a Relative SubroutineCall for Relocatable Z80 Programs

George S Losey

Hawaii Institute of Marine Biology

POB 1346

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In machine language, there are methods of writing re-locatable programs that use a patched routine for ac-complishing calls to subroutines. These methods arevaluable for fast interrupt servicing and similar applica-tions, especially when programs are in modular form butnot residing in specific memory locations.

Although the Z80's operation-code set is well suited tomy needs, I grew frustrated when I found more and moreapplications for my microcomputer. Suddenly, theEPROM- (erasable programmable read-only memory)based program residing at hexadecimal addresses E400through E5FF had to be moved to E800 through E9FF. Allwould have been well if the EPROM's software had usedthe six relative-jump operation codes. The program wasrelocatable, however, because it didn't contain anyreferences to specific (absolute) addresses.

Many programs can be written without using jump andcall instructions that cannot be relocated. However, ifmany portions of your program demand the use of asimilar set of instructions, such as querying an outputdevice or performing arithmetic manipulation, the head-aches begin. Such programs should usually be written ina modular form with a main program that jumps backand forth to frequently used subroutines.

Modular programs use call instructions to access thesubroutines. Since the call instruction contains the ab-solute address of the subroutine (using immediate exter-nal addressing), the code is not relocatable withoutchanging all of the subroutine-call addresses. The generalphilosophy of modular programming with a main pro-gram that calls a variety of subroutines is certainlysound. (See the article by James Lewis, "Some Notes onModular Assembly Programming," December 1979BYTE, page 222.) A glance at the operation-code listingsfor powerful software such as the Cromemco ResidentMonitor reveals a bewildering jungle of subroutine callsthat pack an impressive set of capabilities into a 1 K-bytechip. But if you decide to locate this monitor anywhere

366 October 1981 © BYTE Publications Inc

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Technical Forum.

except the intended address range of hexadecimal EOOOthrough E3FF, sharpen your wits and your pencil, andbest of luck to you. There are more than just a fewimmediate-external address references to change.

To explore this dilemma further, it is important tounderstand three basic differences between a relativejump and a call in the Z80 instruction set. First, therelative jump is a 2-byte instruction that requires fromseven to twelve external clock cycles for fetching and ex-ecution, while the call instruction demands 3 bytes andten to seventeen clock cycles. (Score a few points for therelative jump for saving 1 byte of programming spaceand 1 to 2 microseconds, at 4 MHz.)

Second, the relative jump leaps to the same point in theprogram regardless of where the program resides inmemory, because the jump is made relative to the currentvalue of the program counter. In contrast, the call in-struction includes a 2-byte address for the jump destina-tion, which will obviously be wrong if the program ismoved to another region of memory. Whenever the pro-gram is moved, the 2-byte address must be changed.(Score a pile of points for the relative jump.)

Third, alas, the ignorant subroutine that is accessed viaa relative jump has no idea how to return to the properlocation if it is accessed from more than one place in themain program. The call instruction includes an "in-telligent return" that lets the subroutine jump right backto the next instruction following the call. (Don't despair,save those relative-jump points for later.)

Dennis Kitsz suggested a simple solution to this prob-lem that is fast and requires only a few bytes more than astandard subroutine. (See "Relative Subroutines for theZ80," December 1979 BYTE, page 87.) The only restric-tions to its use are that the program cannot reside inROM (read-only memory), and each time the program ismoved, a single 2-byte address in the program must bechanged. [Also, most programmers prefer to avoid self-modifying code. . . . RSS] However, besides the restric-tion to programmable memory, an error in the calcula-tion of the 2-byte address can destroy the program.

There is another method, which I'll explain shortly,that is more complex but works in ROM and needs nochanges when the program is moved.

The intelligent return is allowed because the call in-struction accomplishes one task that cannot be ac-complished by any of the other Z80 operation codes: asubroutine call pushes the value of the program counteronto the stack while the return from the subroutine popsit back. The program counter is, of course, the registerthat tells the Z80 the address for the next instruction to befetched. If only you could take a peek or push at the pro-gram counter before executing a relative jump, therelative call would be born. A relative-called subroutinecould make an intelligent return to the main program,and the modular program would have relocatable code.Unfortunately, for some undoubtedly sound reason, one

368 October 1981 © BYTE Publications Inc

Circle 320 on inquiry card.

cannot directly push from, pop to, or otherwise gaindirect access to the program counter in the Z80microprocessor.

If you can stand a few sacrifices, I found that the Z80can be coerced to make a relative call. First, the fastestand most direct method for implementing a relative calldemands that 5 bytes of page-zero programmablememory, beginning at one of the eight restart locationsaccessed with the Z80's RST instruction (hexadecimal0000, 0008, 0010, 0018, 0020, 0028, 0030, or 0038), beavailable for storage of a routine that gains access to theprogram counter. Second, each relative call must have a3-byte instruction code, while the actual fetching and ex-ecution of the call will require seventy-one to seventy-sixexternal clock cycles. This means that, at a 4 MHz clockrate, a relative call will take around 15 microsecondslonger than a normal subroutine call. Third, return fromthe subroutine must be unconditional, but it will requireonly four external clock cycles instead of the ten requiredto return from a normal call. Fourth, the HL register pairmust be available for use during the relative call to thesubroutine.

The trick is to use the single-byte RST (restart) instruc-tion as the call instruction. A restart forces a jump to a5-byte routine in page zero of memory, and pushes theprogram counter onto the stack where it is accessible.While you have the program counter's contents corneredon the stack, the 5 bytes of instructions in page zero areused to copy it into an accessible register pair and incre-ment it to point to the instruction immediately followingthe relative call. You then return from page zero to themain program and execute the relative call. "Intelligentreturn" from the subroutine is accomplished by a jump tothe address indicated by the register pair in which youstored the value of the program counter at the time theRST was encountered.

A simple example is given in listing 1. The 5-byteroutine is stored in page zero from hexadecimal 0008 to000C. The relocatable program code is located in a spacearound address hexadecimal 0F00. The HL register pair isused to store the return address for the relative call.

The first relative call begins at hexadecimal 0F00 withan RST 8 instruction, which pushes the program counteronto the stack and jumps to hexadecimal 0008. Thestored value of the program counter (hexadecimal 0F01)is copied into HL with the pop- and push-stack opera-tions. It is then incremented to point to the instructionfollowing the relative call (hexadecimal 0F03). Executionreturns to the relative jump at hexadecimal 0F01. Arelative jump is made to the subroutine at location 0F50.At the end of the subroutine, an "intelligent return" ismade to location 0F03 by jumping to the address con-tained in register HL (JP (HL), a register-indirect jump).When the same subroutine is relative-called by the in-structions at addresses hexadecimal 0F20 through 0F22,the same sequence occurs except that the address register,

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Te<

HL, will contain a different return address, 0F23. Thesame instruction at the end of the subroutine returns tothe main program at 0F23.

The simplest method of creating the relative call is tostore the 5-byte routine in page zero by using a 17-byteinitialization routine, shown here as listing 2, at thebeginning of the main program. It only needs to be ex-ecuted once, so long as you do not overwrite its storagearea.

There are many variations on this theme. Mostnotably, any of the conditional relative jumps may beused, including the Z80's loop-implementing jump in-struction, DJNZ. More important, some systems may re-quire modification of the basic technique. For example, ifthe HL register is busy or must be used to pass informa-tion to the subroutine, the 3-byte relative-call instructioncould be expanded to 5 bytes by adding the EXX instruc-tion (register-set exchange, Z80 op code D9) before andafter the RST 8 instruction, and before the intelligentreturn instruction (JP (HL), Z80 op code E9) in thesubroutine, and after the relative-jump portion of therelative call. The relative-call sequence in listing 1, for ex-ample, would become 3 bytes longer (D9 CF D9 18 4D

D9) while the return from the relative call would become1 byte longer (D9 E9). Note that if this technique is usedfor any relative call to a subroutine, it must be used forall relative calls to that subroutine, since the subroutinenow contains a register-exchange instruction.

If the complementary sets of registers, HL and HL', areboth unavailable, as in an interrupt-servicing program,the IX or the IY index registers could be used. However,incrementing, pushing, and popping these registers re-quires still more bytes of instructions and more time toexecute.

Another interesting possibility exists if you are unableto use page-zero programmable memory. You could, ofcourse, replace the RST instruction with a 3-byte call in-struction to some other idle memory location. But idlelocations have a habit of not remaining idle as your ap-plications evolve. However, if you already have a non-relocatable ROM program, such as a resident monitor, itmay be possible to find a 5-byte space that you can stealas a permanent storage location for the 5 bytes formerlyplaced in page zero. You then have the program merelyexecute a 3-byte call instruction to that address ratherthan execute the 1-byte RST instruction.

Listing 1: Sample implementation of the relative-call (relocatable-subroutine call) function on a Z80-based system. Instead of usingthe normal subroutine-call instruction, subroutines are accessed with a RST (reset) and a relative jump. The RST calls a routine in lowmemory that sets up the return address by placing the proper return address in the HL register pair. This initialization routine thenreturns to the relative-jump instruction immediately following the RST. The RST jumps to the actual subroutine being called. At theend of each subroutine, a normal return is emulated with a jump to the address contained in the HL register.

HexadecimalAddress

ObjectCode

InstructionMnemonic

N (

'00080009000A

E1E523

POPHLPUSH HL

INC HL

m

(00.

000B

. oooc

23C9

INC HLRET

Comment

; copy PC (program counter) into HL

; increment HL to point to subroutinereturn address

; return to the relative call

r

0F00

CF RST 8

0F01

18 4D JR +4D

E

0F03

(sequence of instructions)

E

Prog

ra

c

CO

0F2O

CF RST 8

O

2

0F21

18 2D JR +2D

a.

0F23

(sequence of instructions)

5<o

aso

Q

"55

rr

CD

1 (

0F50

(sequence of instructions)

call page-zero "peek" at PCexecute "relative call"

call page-zero "peek" at PCexecute "relative call"

E9

JP (HL) ; return from relative call

370 October 1981 © BYTE Publications Ire

Listing 2:

Program to set up

the 5-byte initialization routine in low memory (hexadecimal locatic

Hexadec

mal

Object

Instruction

Address

Code

Mnemonic

Comment

N

21 08 00

LD HL, 0008

; load page-zero call pointer

N + 3

36 E1

LD (HL), E1

; load 5-byte string into page zero of memory

N + 5

23

INCHL

N + 6

36 E5

LD (HL), E5

N + 8

23

INCHL

N + 9

36 23

LD (HL), 23

N + B

23

INC HL

N + C

36 23

LD (HL), 23

N + E

23

INC HL

N + F

36 C9

LD (HL), C9

in this example).

For example, one version of the Cromemco ResidentMonitor includes a string of ASCII (American StandardCode for Information Interchange) characters stored toprovide a header output, beginning at hexadecimal loca-tion E3F0. I really don't care whether the header says"CROMEMCO ZM1." or "HOWDY" or "%@$$". Thisis a convenient space to stick the 5 bytes from page zeroso long as I am careful to change any other features of themonitor that refer to this string before programming theEPROM. For my purposes, I can merely shift the wholestring 5 bytes backwards so that I lose two carriagereturns and "CRO". The 5-byte routine from page zerocan then begin at E3FB.

Do be careful if you try this sort of thing. Don't eraseyour old EPROM until you are certain your modificationworks. Another version of the same monitor has a stringof spare bytes (containing hexadecimal character FF)from address E3F5 to E3FF. Inasmuch as any charactercan be written over an FF on an EPROM, the 5-byte codecan be programmed directly onto the chip containing thecode without altering the monitor in any way. Of course,once the 5 bytes are firmly installed in ROM, you canforget the nuisance of having to use the 17-byte initializa-tion routine in listing 2. Merely rewrite your instruction-code manual to list the op codes for your newly createdrelative-call and return-from-relative-call instructions. ■

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October 1981 © BYTE Publications Inc 371

Languages Forum

BASIC, Pascal, or Tiny-c?

A Simple Benchmarking Comparison

Phil Hughes, POB 2847, Olympia WA 98507

Three of the most popular high-level languages formicrocomputers are BASIC, Pascal, and tiny-c. I devel-oped a card-shuffling program in each of these languages,and my experience should help you select the languagefor your needs.

One way of stating the card-shuffling algorithm is:"Store and print the integers from 0 through 51 in a ran-dom sequence." To ensure that the programs performequivalent functions, I added the following conditions:

• The result is to be printed with ten integers per line.

• Following the result, the message "ALL DONE!" is to beprinted on a new line.

• The algorithm is to get a random number, check to seeif it has already been used, and if not, the number is to bestored. The sequence is to be repeated until fifty-twonumbers have been generated.

• The shuffling procedure must be implemented as a sub-routine, and it must be reusable.

Experts or fans of each language could argue with myconditions, saying that they are prejudicial in favor of acertain language. That was not my intent.

I began by looking at the shuffling routine in a Black-jack game that a friend was playing. Its method was tokeep a list of the used cards and generate a new card eachtime there was a draw. At this time, the new card wasadded to the used list. When the used-card list was full, areshuffle, which consisted of clearing the used list, wasforced.

I wondered how long it would take to perform theshuffle by selecting all the cards at one time and storingthem in an array. This method seemed closer to what youdo with an actual deck of cards.

I had been working on a tiny-c interpreter, so I decidedto code my idea first in tiny-c. Because of tiny-c's long ex-ecution time, I then tried my algorithm in Pascal. Finally,I wrote a BASIC version to complete the comparison.

An important factor in this comparison is my experi-ence with each language. I learned BASIC in 1970 as partof my job, and I have used it for development of quick

programs for large-computer systems ever since. I haveused various BASIC interpreters on microcomputers forthe past three years. I have developed a tiny-c interpreter,but I have actually written only two tiny-c programs,each about thirty lines long. I have written three or fourshort Pascal programs. Armed with this information,decide for yourself which language you would use for agiven set of conditions and a given problem.

Tiny-c Coding

Listing 1 is the tiny-c program, and listing 2 is the resultof executing the program. The first nine lines of the pro-gram listing are a (pseudo) random-number generator.This routine appeared in the Tiny-c Owner's Manual(available from Tiny-c Associates). Although this can be

Listing 1: The card-shuffling routine coded in the tiny-c lan-guage. The first nine lines of source code generate pseudoran-dom numbers. The actual shuffling algorithm is coded begin-ning with the line starting with "shuffle".

int seed, lastrandom int little,biyCint range

if( last==0>seed=last=99range=big-littLe+1Last=Last*seedi f(last<0)Last=-lasteturn Li tt Le+ ( las t/8 )/{range

J

intshufintuh

carfie

tern

ilei = 0

t emwli i

if (

dsC51)

Hint current;current=0P,i(current<52)C

p= random(0,51 )

le Ci<current)C

fCcards(i)==temp) break

= i + 1

i==current)C

ards(current)=temp

urrent=current+1

re t u

test

shufint

rn

C

f lei ; i=Uhile (i<52)Cpn cards(i)i= i + 1if Ci;:i(J = = 0)pl"

:

l"all done!"

372 October 1981 © BYTE Publications Inc

Listing 2: Sample execution of the tiny-c program of listing 1.

>.te»t

29 32 -45 21 51 10 12 24 39 25

22 SO 30 1 19 46 44 37 20 26

IB 2EI 34 7 3 49 0 42 27 14

35 13 4 41 & 31 43 23 3S 33

40 36 48 8 5 2 1(5 9 11 17■17 15all done!

thought of as a library function, I decided to include it inthe program. The next seventeen lines are the "shuffle"routine. Finally, the last ten lines (starting with "test[")are the main program that calls "shuffle" and prints theresult.

It was easy to go from the design to the actual tiny-cprogram. It took ten minutes to code the program andanother fifteen minutes to enter it and get it running. Mybiggest problem with tiny-c is remembering that = = isthe relational operator for equality. That mistake cost mea few minutes of debugging time.

Pascal Coding

Listings 3 and 4 show the Pascal program and its execu-tion. Pascal does not have a built-in random-number gen-erator. I borrowed ideas from the sample programs thatcome with the Lucidata Pascal compiler to code the func-tion RANDOM in listing 3. The only difficult part of the

Listing 3: The card-shuffling routine coded in Lucidata Pascal.An explicit random-number-generating function is used here, asin tiny-c.

PASC000D00444

AL PPROG

VARCAISE

PROCVA

COMPILER < VERSION 2 ) : COPYRIGHT C 1980 D.R.GIBBYRAM TEST;<* Shuffle cards and print result *)

12325264761001041081161161241441962 08224236236248252256264268288304324344348368

RDS :: INTED :EDURER

CURRENCTI0VAR

RAN

BEGIN

IF(

RAN

SEE

SEE

RAN

END;

GIN

CURRE

REPEA

II"

TEW

WHI

IF

C

C

END

UNTIL

ARRAYC1. ".52: OF INTEGER;EGER;INTEGER;

SHUFFLE;

NT,TEMP,I : INTEGER;

N RAND0M(LITTLE,BIG : INTEGER) : INTEGER;

GE

INTEGER;

SEED=0) THEN SEED:=99;GE:=BIG-LITTLE+1;I):=SEED*31;D:=SEED MOD 1009;D0M:=LITTLE+S6ED MOD RANGE;

NT:=1;T

1 ;

P:=RAND0M(1,52);LE < ( CAR0SCITOTEMP) AND(I=CURRENT) THEN BEGINARDSCCURRENT1:=TEMP;URRENT:=CURRENT+1;

(CURRENT=53);

CKCUKRENT)) DO I : «I +1 !

END

BEGI

SE

SH

FO

N C* MAIN PGM *)

ED:=0;

UFFLE;

R I :=1 TO 52 DO BEGIN

WHITE (CARDSCI1);

IF ((I MOO 10)=0) THEN WRITELN;<D;

ilTELN;UTELN ("ALL DONE!");

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Listing 4: Sample execution of the Pascal program of listing 3.

+++RUN*SHUFFLE

F'-6a00 RUN-TIME SYSTEM V 1 .2

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DEFAULT STACK RESERVATION $1000CHANGE VALUE T

! COPYRIGHT C 1978 LUCIDATA

43

34

3

11

30

52

1

8

17

45

31

15

27

4

36

33

23

12

25

22

21

7

51

37

44

18

26

10

38

41

5

32

2

6

42

9

46

24

13

40

2?

39

47

14

23

16

50

48

49

20

3S

19

ALL DONE

END OF 1

ROGI

AM

EXE

CUTION.

+++

conversion from tiny-c to Pascal was deciding how to dothe equivalent operation of the tiny-c "break" keyword.("Break" signifies that the innermost "while" loop is to beterminated immediately.) This was implemented inPascal as part of the WHILE condition.

The development and testing of the Pascal programtook about one hour, plus the time necessary to developthe RANDOM function. Much of this time was attribut-able to Pascal's being a compiled language. This made itnecessary for me to use a text editor separate from thelanguage system to make program changes. The biggestproblem I have with Pascal's grammar is rememberingthat : = is the assignment operator.

BASIC Coding

Finally, listings 5 and 6 are the BASIC version of theshuffling program and the execution results. BASIC hadthe advantage of its built-in random-number function,

Listing 5: The card-shuffling routine coded in TSC BASIC. Thebuilt-in RND random-number function is used.

5 0 a I w C ( 51 )

100 GUSUB 1000

200 F0K 1=0 TO 51

210 PRINT C <I);

220 IF INT((I+1)/10)=CI+1)/10 THEN PRINT

230 NEXT I

240 PRINT

250 PRINT "ALL DONE!"

300 END

1000 J=0

1010 T=INT(RND(0>*52)

1020 IF J=0 THEN 1060

1030 FOR 1=0 TO J-1

1040 IF C(I)=T THEN 1010

1050 NEXT I

1 060 C <J) = T

1070 J =J +1

1080 IF J<52 THEN 1010

1090 RETURN

Listing 6: Sample execution of the BASIC program of listing 5.

READY

RUN

27 31 26 48 9 0 36 15 2 17

40 49 39 29 51 1 3 30 6 44

50 5 35 20 18 19 46 28 37 10

24 16 4 14 47 25 7 8 12 42

38 22 34 21 23 13 11 45 43 41

32 33

ALL DONE!

374 October 1981 © BYTE Publications Inc

Circle 151 on inquiry card.

which made the program appear much smaller andhelped out the execution time. The first part of the pro-gram is the main routine. Lines 1000 through 1090 are theshuffling subroutine. It took thirty minutes to developand test this program. The hardest part was convertingthe hierarchical structure of the shuffling subroutine intothe available control structures of BASIC. This resultedin a FOR...NEXT loop and three IF statements.

Table 1 shows the execution times of each of these pro-grams on a Southwest Technical Products Corporation6800 system with a 1 MHz system clock rate. Note thatPascal is compiled, with the compilation process takingabout thirty seconds. Table 2 shows the vendors for thethree language systems.

Conclusions

Tiny-c is an easy-to-work-with language that supportsstructured programming. The source-code interpreter isextremely slow compared with a fast BASIC interpreter,but offers features such as long variable names and struc-tured constructs. These capabilities make debuggingeasy. Also, tiny-c is easy to learn. A tiny-c interpreter forprogram development and a compiler for generating pro-duction programs would be an effective combination.

Pascal offers the structured constructs of tiny-c andmuch more. The execution speed of a compiled Pascalprogram is fast. The price you pay for this is a com-plicated language that is considered by many to be dif-ficult for a beginner to learn. The complexity of Pascalmakes availability of a source-code interpreter unlikely(although a source-code interpreter for a subset of Pascalis certainly possible). The complexity of full Pascal in-creases development time, but once created, a Pascal pro-gram is efficient and relatively easy to understand.

BASIC offers what initially appears to be the shortestprogram. However, on closer inspection of the tiny-cprogram, I found the following. If you were to remove

Language

Execution Time

Tiny-c Version 1.1

160 seconds

Lucidata Pascal Version 2.2 16 seconds

TSC Extended BASIC

23 seconds

Table

1: Comparison of

execution times for the

card-

shuffl

ng routine coded in

i-hree high-level languages.

Language

System

Vendor

Pascal

Lucidata Ltd, POB 128, Cambridge, CB2 5EZ,

England

Tiny-c

Tiny-c Associates, POB 269, Holmdel NJ 07733

BASIC

TSC (Technical Systems Consultants), POB 2570,

West Lafayette IN 47906

Table 2: Companies selling the three language systems com-

pared here.

the random-number function from the tiny-c program(and put it in the tiny-c function library) and move all thecompound statement-delimiter brackets to the same linesas their preceding statements, the tiny-c and BASIC pro-grams would have the same number of lines. The mainproblems with BASIC (at least of most dialects) are itslack of long variable names and hierarchical control con-structs. These two deficiencies make the BASIC programdifficult to understand.

In spite of the individual problems with these lan-guages, each has its place. I hope that I have helped youselect the language that best fits your needs. ■

BYTEs Bits

Scholarship

Competition

Under Way

The fourth annual Interna-tional Computer Programs(ICP) Scholarship awardcompetition for college anduniversity computer scienceand computer technologystudents is under way. TheICP award covers one year'stuition plus expenses to anAmerican college or univer-sity of the winner's choice, upto a maximum of $5000.

Selection of the award isbased on the student's cumu-lative grade-point average inhis or her field of study, over-all grade-point average, needfor financial aid, participa-tion in data processing- andschool-related activities,leadership ability, and ac-complishments and awards.Also, finalists will be asked tosubmit a written essay.

Applications for the com-petition are available at mostfinancial aid departments. Toqualify, applicants must beeither sophomores or juniorspursuing an undergraduatedegree and matriculated in acomputer science or technol-ogy program at an Americancollege or university. Dead-line for filing applications isNovember 15, 1981.

For more information, con-tact Sheila Cunningham,Scholarship Director, ICP,

9000 Keystone Crossing, In-dianapolis IN 46240, (317)844-7461.

Literary Text Project

The Literary Text Project isa nonprofit, voluntary effortby a group of scholars toestablish a computerized sys-tem of custom publishingworks of English literature.

The scholars perceived thatconventional publishers werenot keeping in print low-costselections of many poemswritten from 1660 to 1800, sothey created a data base con-taining the text of poems.Users can order from acatalog printed copies of anypoem in the data base, or anyselection of several poems,thus creating a customizedanthology.

As of April 1981, 150 titlesby major and minor poetswere available through thesystem. The works of Alex-ander Pope and WilliamBlake are excluded from thelist because of their wideavailability. Plans are underway to expand the collectionand the project into otherkinds of literature and otherfields.

Voluntary editorial efforts,advice, and inquiries aresolicited. Contact LiteraryText Project, c/o Dr StephenAckerman, 136 North Caro-lina Ave SE, Washington DC20003. ■

October 1981 © BYTE Publications Inc 375

Programming Quickies

A Fast, AncientMethod for Multiplication

Jostein Nyberg

Odv Solbergsv 100

Oslo 9, Norway

There are several ancient algorithms that adapt sur-prisingly well to the computer. One such example is the"Russian Peasant Method" for multiplication, which wasdiscovered by Western visitors to Russia in the nineteenthcentury. However, the method is actually much olderthan that. It was used by Egyptian mathematicians asearly as 1800 BC, although it was not stated as a com-pletely systematic algorithm.

To explain this method, let A and B denote twonumbers. A can be any number, while B must be a non-negative integer. The problem is to calculate their prod-uct P. The method is:

1. Let P = 0

2. If B is odd, let P - P + A

3. Let A = A + A

4. Let B = integer part of B/2

5. If B is nonzero, repeat fromstep 2; otherwise the algo-rithm terminates.

An example will clarify how this works. Here are suc-cessive values of A and B, when their initial values are175 and 18:

A: 175 350 700 1400 2800 5600B: 18 9 4 2 1 0

Adding those As for which the corresponding Bs are odd,we have:

P = 350 + 2800 = 3150

which is the required result of 175 times 18. You maywish to try more examples to convince yourself that thisprocedure works correctly.

Notice that if A and B are unsigned integers expressedin binary, the doubling of A in step 3 can be performedby a left shift of A. Finding the integer part of B/2 in step4 corresponds to a right shift of B. Furthermore, the B instep 2 is odd if its least-significant bit is 1.

Listing 1 shows a relocatable subroutine written in6502 assembly language; also included is the hexadecimalobject code. When the subroutine is entered, it is assumedthat the low- and high-order bytes of A are found atmemory locations 0000 and 0001 (hexadecimal), respec-tively. The low- and high-order bytes of B are found atlocations 0002 and 0003, respectively. When the end ofthe subroutine is reached, locations 0004 and 0005 willcontain the product P. If needed, the routine can be madeshorter and faster by using the index registers (X and Y)for the product, instead of memory locations.

It is assumed here that P does not exceed 16 bits. Ifthree or four bytes are required, it's relatively easy to ex-pand the subroutine.

Multiplication routines similar to the one in listing 1are found in arithmetic software and are coded in variouslanguages. This does not mean that the routines' inven-tors were intentionally using the Russian PeasantMethod. Probably, they were just imitating the familiarpencil-and-paper method for multiplication. As a matterof fact, when the numbers involved are binary and thealgorithms are executed using the same instruction set,these two methods are identical.

A multiplication routine that looks slightly different,listing lb, is often shown in microprocessor and micro-computer manuals. As a rule, this method should not beused. The loop starting at HALF is always entered sixteentimes. Thus, the looping can continue to no purpose afterB reaches 0.

The Russian Peasant Method can be modified to per-

376 October 1981 © BYTE Publications Inc

Circle 125 on inquiry card.

form exponentiation. By setting P equal to 1 in step 1 andchanging the addition in steps 2 and 3 to multiplication,the resulting value of P will be A raised to the power of B.Of course, steps 2 and 3 now assume that a multiplicationroutine is available. This method for exponentiation wasstated by a Persian mathematician in the year 1414. ■

Reference1. Knuth, D E. The Art of Computer Programming, Vol 2.Reading MA: Addison-Wesley, 1969. Pages 399 and 400.

Listing 1: Relocatable subroutines for fast integer arithmetic onthe MOS Technology 6502 microprocessor. Listing la shows amachine-language routine for multiplication by the Russian Pea-sant Method; listing lb gives a version seen frequently in text-books.

(la)

Object

Code

Label

Mnemonic

A9

00

MULT

LDA

#0

85

04

STA

PLOW

85

05

STA

PHIGH

46

03

HALF

LSR

BHIGH

66

02

ROR

BLOW

90

0D

BCC

DOUBLE

18

CLC

A5

04

LDA

PLOW

65

00

ADC

ALOW

85

04

STA

PLOW

AS

OS

LDA

PHIGH

65

01

ADC

AHIGH

85

05

STA

PHIGH

06

00

DOUBLE

ASL

ALOW

26

01

ROL

AHIGH

A5

02

LDA

BLOW

05

03

ORA

BHIGH

DO

E3

BNE

HALF

60

RTS

(lb)Object

Coda

Label

Mnemonic

A9

00

MULT

LDA

#0

85

04

STA

PLOW

85

05

STA

PHIGH

A2

10

LDX

#$10

46

03

HALF

LSR

BHIGH

66

02

ROR

BLOW

90

0D

BCC

DOUBLE

18

CLC

AS

04

LDA

PLOW

65

00

ADC

ALOW

85

04

STA

PLOW

A5

05

LDA

PHIGH

65

01

ADC

AHIGH

85

05

STA

PHIGH

06

00

DOUBLE

ASL

ALOW

26

0.1

ROL

AHIGH

CA

DEX

DO

E6

BNE

HALF

60

RTS

SSS?

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October 1981 © BYTE Publications Inc 377

Hardware Review

Integral Data's Paper Tiger 460

Eliakim Willner, datatronics inc, 675 Third Ave, New York NY 10017

Until very recently, a prospective purchaser of a com-puter printer had to choose between letter quality andspeed. The letter-quality printers, which most often usedaisy-wheels to produce fully formed characters, are tooslow for typical data-processing applications. Fasterprinters usually employ a dot-matrix print head that pro-duces readable, but not letter-quality, type.

A new breed of printer on the market today showsrefinements in dot-matrix technology, producing typethat approaches letter quality without sacrificing speed.Integral Data Systems' 460, the "Paper Tiger," is aworthy representative of this new breed. With minor ex-ceptions, the IDS 460 has every feature that a hobbyist orsmall-business user could reasonably expect to find.

The printer is about as wide as most in the dot-matrixfamily, but it is taller and not as deep. It appears to besolidly constructed and designed to withstand heavy use.Most of the electronics, including a microprocessor tocontrol the many advanced functions, are contained on asingle, easily accessible circuit board under the printer'senclosure.

The enclosure is made of durable structural foam andhas a pleasing look. Most of the controls are convenientlyplaced. On the upper right-hand side of the printer are aformset/online/offline switch and a formfeed/linefeedswitch (see photo 1). The IDS 460 also has a self-testswitch on the upper left-hand side which generates arepetitive test pattern. (Upon power-up, a diagnosticroutine automatically clears the buffer and tests theprinter's memory.) Next to the self-test switch are twoDIP (dual-inline package) switches placed so that it iseasy to change their settings deliberately, but difficult todo so accidentally. These switches are used for selectingmany of the printing options that will be discussedshortly.

The IDS 460 has indicators for power-on, online, andfault. The fault indicator flashes when the power-updiagnostic encounters a hardware problem and lightswhen the printer runs out of paper.

Under the cover is a knob that moves the print-headmechanism back and forth, thus varying print intensity.This is useful for accommodating changing paper thick-ness. When printing thick labels, for example, the printhead can be moved further back from the ribbon, savingwear on the head without affecting the quality of theprint.

Unfortunately, this control is not easy to use. Theknob is not calibrated, so trial and error is required to get

Photo 1: The Integral Data Systems' Model 460 dot-matrixprinter, better known as the Paper Tiger. At the upper right arethe formset/online/offline switch and the formfeed/linefeedswitch.

378 October 1981 © BYTE Publications Inc

the correct print intensity. If only one kind of form is tobe used, this adjustment need only be done once. If theform is changed frequently, however, the constant re-adjustment can be inconvenient.

Still more inconvenient is the fact that this knob isplaced beneath the printer enclosure. The enclosure issecured to the chassis with four knurled retainer nuts. Toremove the enclosure the nuts are loosened and the en-closure is lifted directly upwards. There is little clearancebetween the enclosure and the chassis. Invariably theenclosure rubs against the circuit board or the tractormechanism, or snags the ribbon. The knob for varyingprint intensity should certainly have been placed outsidethe enclosure.

Other controls are placed underneath the enclosure.These include the 115/220 V switch and various jumpersused to select the desired interface, but these are usedinfrequently.

Two secure tractors move paper through the IDS 460.There is no problem handling thick labels or multiple-part forms. Fanfold or roll paper up to ten inches widemay be used. (The IDS 560 is similar in many respects tothe 460, but it accommodates paper up to fourteen incheswide.) An internal paper-roll holder that fits under theenclosure is available as an option, as is a paper-catch

At a dunrp

Name

letter carrier, various inter-

Paper Tiger 460

facing cables and connectors

Use

Features

High-speed, correspondence-

Printer speed, 150 cps; paper

quality printer

slew rate, SVi inches per sec-

ond; built-in self test and

Manufacturer

diagnostics; printing pitch

Integral Data Systems

sizes of 5, 10, 12, 16.8 char-

Milford NH 03055

acters per inch; fixed/

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Dimensions

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31 by 40 by 32 cm (12V2 by

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Price

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October 1981 © BYTE Publications Inc 379

Circle 253 on inquiry card.

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We are dealers for BASF, DYSAN, 3M(SC0TCH) Dis-kettes, Cartridges, Mag Tape, etc. In addition we carry acomplete line of Printer Ribbons and other data process-ing accessories.

—■l_^_/#Sgl 1840 LINCOLN BLVD.,

T|lCn/^! SANTA MONICA, CA 90404

Uljll/ JJ (213) 450-5911 (CALL COLLECT)MART, INC PRICES SUBJECT TO CHANGE

basket and a letter carrier that allows printing of letterson single sheets.

The ribbon comes in a sealed cartridge, which"facilitates fast, easy replacements" according to themanufacturer. The ribbon must still be handled man-ually, however, and I did not find the cartridge any easierto install than an ordinary—and far less expen-sive—spool.

Although this ribbon is said to have a longer life thanan ordinary ribbon, it is easily tangled when theenclosure is removed and replaced; then the cartridgemust be discarded. A new one costs $12. The user iswarned to use only cartridges supplied or approved byIntegral Data Systems, although the item appears to bestandard.

The IDS 460 can be connected immediately to almostany computer. Other printers require that the buyerspecify the interfacing standard when placing an order.This printer has built-in circuitry for almost any interfac-ing standard. A jumper selects either parallel (Centronics-compatible) or RS-232 serial interfacing. The XON/XOFF handshaking protocol used by many of the daisy-wheel printers is also recognized. The user can select anyone of five serial baud rates up to 9600 baud by using theDIP switches on the top of the printer. The DIP switchesalso allow the user to easily define the parity-checkingfunctions for received data.

I had a little difficulty getting the printer to operateproperly when connected to my LSI-ll/2-based system.The individual I spoke to at IDS was knowledgeable andhelpful. He suspected that the problem might be traced tothe printer's firmware and offered to send me a set of re-vised PROMs. I discovered that the problem was not inthe printer at all; nevertheless, the new PROMs arrivedpromptly, and at no cost.

The IDS 460 shines particularly well in the area of printquality: it is superb and well complemented by a power-ful array of character and forms-control options. Thecharacters are clear, crisp, and well formed. The lettersare not the mere outlines produced by most dot-matrixprinters, but are shapely and filled in, almost like lettersoff a printing press. Distinct dots are not visible becausethe print head produces the dots in an overlappingpattern.

Four different print densities are software or DIPswitch selectable—5, 10, 12, or 16.8 characters per inch.The following are also hardware or software selectable:proportional spacing (you can even control the amountof space between characters), text justification (I), linespacing at either 6 or 8 lines per inch, and one of eightform lengths, from 3 to 14 inches. And despite theexcellent print quality, the speed of the printer comparesfavorably with the faster dot-matrix printers. The IDS460 uses bidirectional printing and logic that minimizesmotion of the print head over white space on the page.

The IDS 460 firmware performs many of the functionsnormally handled by text editors; it should be relativelyeasy to program a text editor to take advantage of the

380 October 1981 © BYTE Publications Inc

Circle 127 on inquiry card.

TTI-i <3

IDS

4 <S O —

D <e m. one t rat

x o XT.

13 PRINT For program listings, a 'no frills' format is preferred."

20 FRUIT "In that case, one would use the standard 80 column listing"

3 0 FRI NT "with no proportional spacing or text justification."

4 0 END

For word processing, however most writers will opt to use proportionalspacing. This means that individuals letters will be of different widths,giving the document a more professional appearance The ability to dothis is characteristic of better letter quality printers.

K;t:ce that mace characters sin be tit on a line that is proportionallyspaced, giving the text a "smaller" look. When one uses the smallesttype an in conjunction with the proportional spacing feature the resultis teit that is quite small — suitable for footnotes, perhaps.

This size is the one that I generally use, 12 characters per inch. The IDS 460 is a versatile printer.The manufacturer promises to make it even more versatile by making available PROM chips to enable switching betweentwo typefaces. With this feature it would be possible to switch back and forth from a language to another. However,it you do not want to wait for the PROM chips to become available, you can accomplish the same thing by usingthe graphics function of this printer.

1 hear you have

new printer, Eli, 21U 5TiJ !

Figure 1: Sample printout of the Integral Data Systems' Model 460. Although the Hebrew characters in the last line were printedusing graphics features, IDS is planning to introduce PROMs that will permit switching from one language to another.

many features. Examples of some of these features in-clude the following: the DIP switches may be used toenable or disable an automatic one-inch skip at formboundaries; horizontal tab positions can be set by usingsoftware escape sequences; on receiving a horizontal tabcharacter, the print head tabs to the next specified col-umn in the line. You can also set vertical tab posi-tions—in fact, you can program three separate verticaltab schedules since there are three separate vertical tabcharacters. Print-head motion and paper motion are ex-tremely precise. Horizontal tabbing may be specified in1/120 inch increments; vertical tabbing in 1/12 inchincrements.

One other minor inconvenience is that no default tabsetting takes effect when the printer is powered up. Thismeans that unless the user remembers to explicitly pro-gram tab positions, the printer ignores the tab character.In text, the tab character is frequently used, instead ofblanks, to conserve storage space. If you send such text to

the printer before setting tabs, the text will look as if allthe blanks mysteriously disappeared. The solution issimply to set the tabs, but there really should be a defaultsetting.

In addition to its text-processing prowess, the IDS 460,when equipped with the Dot Plot option, is an excellentgraphics printer. Sending a controI-C to the printer putsit into graphics mode, and every following character isinterpreted as a graphics pattern until graphics mode isswitched off with another control-C.

Each character controls seven dots in the verticalplane. Each bit in the 7-bit ASCII (American StandardCode for Information Interchange) code of the characteractivates a different dot, with the leftmost bitcorresponding to the lowest of the seven dots. If theASCII code sent is 1000011, for example, the IDS 460prints the bottom dot and the two top dots. A graphicscarriage control advances the paper a distance of sevendots.

October 1981 © BYTE Publications Inc 381

Conclusions

• The IDS 460 has excellent print quality—probably thebest of all dot-matrix printers in its price range. The nine-wire head uses both vertical and horizontal overlappingof dots to make fully formed characters and give lower-case letters full descenders.

• The bidirectional, logic-seeking printing minimizesprint-head motion and assures high-speed operation.

• Interfacing the IDS 460 to a variety of printers is re-markably simple because the printer contains both RS232and parallel interfaces.

• The only real drawbacks result from the difficulty ofremoving the cover and the placement of the print-intensity switch inside. Before changing from paper ofone thickness to paper of another thickness, the user mustremove the cover and adjust the print-intensity switch.

• Although the printer lacks a friction-feed feature andcan't handle single sheets of paper, it does offer extremelyprecise paper handling.

• The IDS 460 has a convenient self-test feature and anindicator that lights or flashes when paper runs out orhardware problems occur.

• When equipped with the Dot Plot option, the IDS 460offers outstanding graphics features.

• Judging by its willingness to help when I encountered aproblem, Integral Data Systems can be relied on for prod-uct support.

• I recommend the IDS 460 to anyone who can't spendseveral thousand dollars and yet needs a printer that hasboth excellent print quality and the speed of dot-matrixtechnology. ■

IF YOU ENJOY MUSIC, WHY JUST LISTEN?

You and your Apple could be makingbeautiful music together!Join the thousands of Apple owners who aremaking music — without the years of practiceneeded for conventional instruments. You canquickly and easily enter a song from sheet music,lust follow the detailed examples and instructionsprovided.

THE PRODUCT. ALF's economical 9-voice MusicCard MC1 is just $195, the gourmet 3-voice MusicCard MC16 is $245 (use 2 for 6 voices or 3 for 9).Both come with detailed manual, complete soft-ware, and cable for connection to your stereosystem.

THE SOFTWARE. We're convinced our product isby far the easiest to use and most versatile systemfor the Apple. You get many features not availablein other systems, plus a very large note capacity.And no customer has ever reported a "bug"or error.

THE HARDWARE. ALF strives for the best qualitypossible. No MC1 card has ever been returnedwith a manufacturing defect.THE COMPANY. ALF has been making computer-controlled synthesizers since 1975. We made thefirst music peripheral for the Apple — and it's stillone of the most popular.

Available through Apple dealers, or write formore information.

WANT TO DUPLICATE DISKS QUICKLY?

ALF's disk duplication service has been a majorsource of quality reproduction for Apple-compatible software houses since 1980. Now youcan use the same techniques for fast and accuratereproduction yourself, with ALF's Copy System.Why spend over $10,000 for a duplication systemwhen for just $595 you can connect the ALF CopySystem to your own Apple! Copying time is about37 to 1 7,3 seconds, depending on number of drivesused. That's over 1,600 disks in 8 hours from asingle system. Are you completely confident ofyour present copying methods? At ALF, accuratereproduction is more important than speed. TheALF Copy System is designed to produce perfectcopies every time.

Special hardware and software copies any stan-dard 13 or 16 sector Apple format disk. Hardwareplugs easily into computer — no permanentchanges required. If you wish to do your own drivemaintenance, the manual tells how to use stan-dard Shugart procedures and accessories, and allnecessary software is included.

Too busy to get into disk copying? You can stillcount on ALF's convenient copying service. Askabout our copy-resistant and "double boot"services too!

Write for complete details.

NEED CONVENIENTFLOPPY DISK PROTECTION?

ALF's Floppy Boxes are specially designed to offergreat protection with more convenient use thanother methods. They're designed with two layersof corrugated cardboard with a special "cross-grain" construction for extra strength The stan-dard square size holds 1-3 minifloppies for mailingor packing in products. The larger rectangular sizeholds minifloppies plus a standard 5VS x ISVibooklet (8'/j x 11 folded in half). Available with anadhesive closure tab for use as a mailer (just sealwith tab, address other side, and mail). Softwarehouses: write for details on attractive, protectivepackaging for your products

Small quantity price is 75<p for standard box.

Available singly at computer dealers, in large

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Au£ 81

LF PRODUCTS INC. 1448 ESTES DENVER, CO 80215

382 October 1981 © BYTE Publications Inc

Hardware Review

The Mauro Proac Plotter

Mark Dahmke

1515 Superior Apt 15

Lincoln NE 68521

The Mauro Proac plotter provides the small-computeruser with an inexpensive way of obtaining high-qualitygraphics. The plotter uses a novel method of controllingthe paper—it embosses a pattern on the edge of the paperthat is used to guide the paper across the drive roller. Acentrifugal blower creates a pressure drop across the

Hardware

6800 microprocessors;

Mauro MP-250

two-dimensional and

Proac plotter

perspective plotting pack-

ages available; may be

Use

driven from FORTRAN,

general-purpose

BASIC, etc.

plotter

Hardware required

Manufacturer

any 8080/Z80, 6502, or

Mauro Engineering

6800 microprocessor; re-

Rt 1 Box 133

quires either a 6-bit

Mount Shasta CA 96067

parallel output port or

(916) 926-4406

the RS-232C interface op-

tion.

Price

plotter, $695

Hardware options

RS-232C serial interface,

roll paper adapter

$195

RS-232C serial data

TRS-80 or Apple

interface

interface, $85

TRS-80 or Apple II

interface cards

Features

plots on ordinary 8V2 by

Documentation

11 paper

26-page manual including

choice of pen colors and

interfacing requirements,

line widths

sample software drivers,

0.005 inch/step resolution

and a listing of the 8080

2.5 inch/second plotting

assembler interface

speed

program.

Software

Audience

full vector driver soft-

anyone requiring quality

ware available for

pen-plotter graphics at

8080/Z80, 6502, and

low cost.

paper writing surface, assuring that the paper is held inplace. Both X and Y axes are driven by stepper motors,and the pen is moved up and down by a solenoid.

The plotter will accept single 21.5- by 28-cm (8V2- by11-inch) sheets, 28- by 43-cm (11- by 17-inch) sheets, or a28-cm (11-inch) continuous roll (if equipped with the roll-paper option).

Control Circuit

The electronics package will accept control signalsfrom the host computer via six data lines: — Y, + Y, —X,+X, pen-control (up/down), and home. Limit switchesare provided on all axes to prevent overrun of the pen.The electrical interface consists of TTL (transistor-transistor logic) signals. All lines come out to a 10-pinMolex connector on the back of the plotter.

Sending commands to the plotter is somewhat morecomplicated. For example, if you want to step in the +Xdirection, you have to hold the —X line high (logic 1) andsend four positive-going pulses to the +X input. Thiscauses the motor to advance one 0.005-inch step in the+X direction. The same procedure is required for theother three controls (— X, + Y, and — Y). The pen may belowered by pulling the pen-control line low (logic 0) afterit has been placed in the high (logic 1) state. Raising orlowering the pen takes approximately 100 ms.

Serial Interface

The serial interface allows users with an RS-232C serialdata port to communicate with the plotter without hav-ing to wire up a special cable for the parallel interface. Itnormally runs at 1200 bps (bits per second), but may beswitched to 110, 300, or 2400 bps. The interface expectsto see 7 data bits and 1 or 2 stop bits. The eighth, or pari-ty, bit is ignored. To communicate with the serial inter-face, several bytes are sent in the following sequence:

Byte 0: Control word

Byte 1: Y LOB, (low-order bits) bits 0 to 6 (bit 7 ignored)

Byte 2: Y HOB, (high-order bits) bits 0 to 4 (bit 5 is the

sign bit, and bit 6 is the pen-control bit)

Byte 3: X LOB, bits 0 to 6 (bit 7 ignored)

October 1981 © BYTE Publications Inc 383

Circle 181 on inquiry card.

Main/Frames «. $200

Main/Frames ^ $200

' 14 Basic Models Available

i Assembled & Tested■ Power Supply:

8v@15A, ± 16v@3A' 15 Slot Motherboard

(connectors optional)> Card cage & guides« Fan, line cord, fuse, power

& reset switches, EMI filter• 8v@30A, ± 16v@10A

option on some models

RackmountedMain/Frame

8" Floppy Main/Frame

(includes power tordrives and main/frames)

Write or call for ourbrochure which includes our

application note:'Building Cheap Computers'

INTEGRAND

8474 Ave. 296 • Visalia, CA 93277 • (209) 733-9288We accept BankAmericard/Visa and MasterCharge

EXPAND

APPLE AND ATARI

16K RAM CARD

These exciting new additions to our line will meet the demand forlow cost alternatives to the higher priced language and ramcards. The ConComp Apple II 16K Ram Card will work with allexisitng software compatible with the Apple Language Card' andthe Microsoft Z-80 Softcard.5 Allowing up to 64K of user memory,the Ram Card helps make complete use of Pascal, CP/M," andlarger programs like VisiCalc.3 The Atari 8002 version iscompatible with all Atari software.

Both cards are constructed using high-speed high-qualitydynamic RAM and come with a full one year warranty.

For more information please call or write.

APPLE II$130

ATARI 800$89

384 October 1981 © BYTE Publications Inc

'Trademark of Apple Computer Inc.

'Trademark of Atari Inc.

"Trademark of Personal Software Inc.

'Trademark of Digital Research

'Trademark of Microsoft Consumer Products, Inc.

ConComp Industries

8338 Center Dr.La Mesa, CA 92041(714) 464-6373

Dealer Inquiries Invited

Circle 399 on inquiry card.

Photo 1: The Mauro plotter is a low-cost, well-engineered unitdesigned with the small-system user in mind.

Byte 4: X HOB, bits 0 to 4 (bit 5 is sign bit, bits 6 and 7are ignored)

The control word tells the interface how it should inter-pret the succeeding bytes. Bits 0, 1, and 2 define howmany vectors (4-byte groups of bytes 1 through 4) will besent. Bit 4 indicates whether the buffer-full response ofthe interface is a pulse on the RS-232C CTS (Clear toSend) line or a specific character. Bits 3, 5, and 6 arereserved, and bit 8 is ignored.

Software

Several device drivers for the 8080/Z80, 6800, and6502 microprocessors (in both BASIC and assembly lan-guage) are provided with the plotter and the interface.The program driving the plotter (without the serial inter-face) uses the same byte order and format as the aboveprotocol for the serial interface. This greatly simplifiesconversion (not to mention program compatibility) fromone to the other.

Another vendor—Leapac Services (8245 Mediterra-nean Way, Sacramento CA 95806)—supplies several two-and three-dimensional plotting packages at reasonableprices. The L2D package is a simple two-dimensionalpackage with Calcomp-compatible routines. The L3P is athree-dimensional perspective-plot package containingover seventy subroutines, including zoom, fly-by, andanimation functions.

Both packages are available from Leapac on eitherCP/M-format 8-inch floppy disks or North-Star-format5-inch disks. Each package is provided as a linkablelibrary for Microsoft-compatible compilers such asFORTRAN-80, COBOL-80, MACRO-80, and the BASICcompiler.

Conclusions

In general, I found the documentation of the Mauroplotter to be adequate but not exceptional. The plotteritself is well engineered and constructed. I had few prob-lems with the unit, except for a troublesome serial inter-face. However, this was quickly replaced after a call toMauro Engineering. Of the many plotters 1 have lookedat over the past three years (with hopes of finding one Icould afford), the Mauro Proac plotter comes closest tobeing the ideal small plotter. ■

Software Review

The Radio ShackFORTRAN Package

Tim Daneliuk, 4927 North Rockwell, Chicago IL 60625

FORTRAN, a high-level programming languagegeared to scientific and mathematical programming, isprobably one of the few languages to have found "univer-sal" acceptance. Until recently, however, FORTRAN(FORmula TRANslator) has been unavailable to the per-sonal computer user.

For those who are familiar only with BASIC(Beginner's All-Purpose Symbolic Instruction Code), afew words concerning "compiled" and "interpreted"languages are in order. BASIC as implemented on theTRS-80 is an interpreted language. As a program runs, itis translated, line by line, from English (which the com-puter can't understand) to the computer's own "machinelanguage." Each line of the program is executed as it is in-terpreted. Note that the program (called source code)never changes: it is simply interpreted each time you typethe RUN command.

FORTRAN, on the other hand, is a compiled language.As in BASIC, the source code is written in English-likestatements which, though not identical to those inBASIC, are similar in principle (ie: there are suchelements as input/output statements, arithmetic expres-sions, and logical expressions). To run the FORTRANprogram, however, you must use a special machine-language routine called a compiler. The compiler goesthrough source code and creates a second machine-language program, called object code. This transforma-tion from source to object code is performedonce—thereafter, when you want to run your program,you actually execute the machine-language object codeproduced by the compiler.

For this reason, programs written in compiledlanguages such as FORTRAN are very fast: typicallytwenty to thirty times faster than the equivalentalgorithm written in an interpreted language. The pricefor this efficiency is increased difficulty in editing anddebugging because a program must always be compiledbefore it can be run.

The Package

With the exception of a few extensions and restrictions,the FORTRAN package described here conforms to the

1966 ANSI (American National Standards Institute)FORTRAN. Radio Shack's FORTRAN (actually writtenby Microsoft and licensed to Radio Shack) comes in athree-ring binder that includes two 5-inch floppy disksand about 200 pages of documentation. The documenta-tion is not a tutorial in FORTRAN, however, and if youdon't know FORTRAN, it is probably insufficient. RadioShack recommends several textbooks to augment the in-formation supplied.

The FORTRAN package comprises four files. Disk 1contains the FORTRAN compiler and the editor; Disk 2contains the linking loader and the FORTRAN library.Each file has an associated section of documentation, andthere is a sample FORTRAN program, along with in-structions for entering, compiling, linking, and runningit. Each disk has the TRSDOS 2.3 operating system on it.

Ar a danrp

Name

Computer

Radio Shack

Radio Shack Model I

FORTRAN

Level II with expan-

sion interface,

Type

minimum 32 K bytes

High-level language

of memory, and at

compiler

least one disk drive

(two recommended)

Manufacturer

Licensed by Microsoft

Documentation

to Radio Shack

Approximately 200

One Tandy Ctr

pages in a loose-leaf

Forth Worth TX 76102

binder

(817) 390-3011

Audience

Price

Language enthusiasts,

$99.95

FORTRAN users, and

users with scientific

Format

and mathematical ap-

Two 5-inch floppy

plications

disks

Language

Z80 machine language

October 1981 © BYTE Publications Inc 385

Circle 165 on inquiry card.

Free. Fast. Anda phone call

INMAC INTRODUCES

THE SOLUTION TO YOUR MICRO SUPPLY

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• One-Stop Shopping. This new catalog offers over 1,000products specifically for Micro Computers. Compatible withApple. Atari, Northstar, TRS-80s and many others.

• Convenient Ordering. By mail or phone, ordering suppliesand accessories from this catalog will be guick and easy.

• Fast Delivery. We'll ship your order within 24 hours from ourdistribution centers in New Jersey, California, Illinois and Texas.Overnight delivery available.

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The documentation claims that the Disk BASIC files areincluded, but they were nowhere to be found on mycopies.

Although this FORTRAN package is best suited forsystems with dual disk drives, I was able to use it suc-cessfully on a single drive system. The only real disad-vantages were that I had to exchange the disks constantly(a problem familiar to anyone who has tried to make acopy of a disk using a single drive system), and theamount of free disk space was limited. The reason for thisis that the disk containing the final executable commandfiles—created from your source code—will always con-tain part of the FORTRAN software. This will be dis-cussed later in the article.

The Editor

The Microsoft heritage is most apparent in the editor.Anyone familiar with the Level II BASIC or MicrosoftEDTASM (Editor-Assembler) editing commands will feelright at home with this editor. It is also the best-documented portion of the package, although in my

Extensions to ANSI-66 FORTRAN

• // c is used in a 'STOP c or 'PAUSE c statement, c may beany six ASCII characters.

• Error and end-of-file branches may be specified in READand WRITE statements using the ERR = and END = options.

• The standard subprograms PEEK, POKE, INP, and OUThave been added to the FORTRAN library.

• Statement functions may use subscripted variables.

• Hexadecimal constants may be used wherever Integer con-stants are normally allowed.

• The literal form of Hollerith data (character string betweenapostrophe characters) is permitted in place of the standardnH form.

• Holleriths and Literals are allowed in expressions in placeof Integer constants. '

• There is no restriction to the number of continuation lines.

• Mixed-mode expressions and assignments are allowed, andconversions are performed automatically.

Restrictions on ANSI-66 FORTRAN

• The COMPLEX data type is not implemented. It may beincluded in a future release.

• The specification statements must appear in the followingorder:

a) PROGRAM, SUBROUTINE, FUNCTION,BLOCK DATA

b) Type, EXTERNAL, DIMENSION

c) COMMON

d) DATA

e) Statement functions

• A different amount of computer memory is allocated foreach of the data types: Integer, Real, Double Precision, andLogical.

• The equal sign of a replacement statement and the firstcomma of a DO statement must appear on the initial state-ment line.

386 October 1981 © BYTE Publications Inc

Circle 175 on inquiry card.

Circle 119 on inquiry card.

judgment it presents the least difficulty.

The purpose of the editor is to create, edit, and storeFORTRAN source code. It assigns line numbers and in-crements to the program statements. The line numbersare not actually part of the FORTRAN program, but theyexist so that specific lines can be called for editing. Onlycertain FORTRAN statements such as DO loops andWRITE operations require line numbers, and these are in-cluded in the FORTRAN statement-field.

The usual interline and intraline editing commands areprovided. The interline commands can insert, delete, re-place, and print lines, or groups of lines, in the program.The intraline commands edit characters or groups ofcharacters within a given program line (eg: a charactercan be deleted within a line of the program and then re-placed with three other characters).

The line editing commands are simply extensions of theediting facilities provided with Radio Shack's Level II andDisk BASIC software. However, the elegance of thiseditor is substantiated by the presence of two other com-mands: Find and Substitute. The Find command finds agiven string of text within a source file and prints out thecorresponding line numbers. The Substitute command issimilar to the Find command, except that a givencharacter string can be replaced with another characterstring in a selected group of lines. It would, for example,be possible to substitute FORMAT(2 for FORMAT(5wherever it appears in lines 100 to 500. These two com-mands are tremendous time-savers, particularly if you areediting long files in which the same change must be mademany times.

There are two final features of interest. First, as is com-mon to most FORTRAN source listings, the editor ap-pends page numbers to the listing, as necessary, whichfacilitates the organization of long files. Second, theeditor can be used to edit certain BASIC and other non-FORTRAN files. (The BASIC file must be stored as a textfile.) This allows you to use the find/substitute com-mands when editing BASIC files.

The Compiler

The FORTRAN user never comes into direct contactwith the compiler. Rather, he writes source code accord-ing to the strict grammatical rules of the language. Thecompiler in turn is able to recognize and process thesource code. As mentioned previously, this FORTRANfundamentally conforms to the ANSI-66 standard. Thetext box on the left, excerpted from the reference manual,shows the departures from the standard.

FORTRAN is recognized as a language that is well-suited to the scientific and mathematical user. This bias isreflected in the data types that are available:

Integer: from -32768 to 32767

Real: seven-digit precision from ±10~38 to ±10+38

Double precision: same as real except with 16-digit

precisionLogical: used in logical operations such as AND, ORLiteral: alphanumeric stringsHexadecimal: numbers in base 16

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All international group of professionals lias designed and programmed SATELLITETRACKING SOFTWARE, a unique package ol five separate programs that allow youto set up your own Satellite Tracking Station using your microcomputer. Beginners,professionals, and educators will all appreciate the technical excellence of thiseasy to use software. Satellite positions are calculated and displayed or printedout, including the lollowmg data: altitude, azimuth, elevation, right ascension,decimation, and range, for any time — past, present or future. The 30 pageoperator's manual includes notes on interpreting NASA documents and takingobservations. The Apple. TRS-80. and Sorcerer versions plot satellite positions on amap of the world. The Sorcerer version is available only on casssette. The TRS-80version is for a Model I, level II TRS-80.

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Circle 312 on Inquiry card.

October 1981 © BYTE Publications Inc 387

One glaring omission is the complex data type. StandardANSI FORTRAN allows direct manipulation of complexvariables—a real time-saver when solving problems inphysics, electronics and related fields. I suspect that thisdata type was omitted because of the memory it wouldrequire to handle complex variables. Nevertheless, itshould have been offered as an option (ie: two versions ofthe compiler, one with and one without the complexvariable type).

This version of FORTRAN is characterized by exten-sive formatting statements that give the programmergreat control over how data is input, output, and stored.These statements include numeric, logical, Hollerith (orstring), and scaling-type format commands. User-definedfunctions are also allowed through the construction offunction subprograms. The usual transcendental func-tions, such as sine, cosine, and arctangent, are included,as well as the hyperbolic tangent. And, of course, the

package includes all standard FORTRAN arithmetic andcontrol statements such as GOTO (three kinds), IF, andPAUSE.

The Linker and FORTRAN Library

The linker relocates in memory the object code thatwas created by the compiler, and it must do so in a man-ner that will allow the object code to be directly executed.In other words, the linker goes through the relocatableobject file that the compiler has created, and from this,creates a command file that can be directly executedunder TRSDOS 2.3. During this process, the linkerreferences another file called FORLIB. FORLIB containsall the standard routines for addition, subtraction,transcendental functions, etc, so the compiler does nothave to recreate the same machine-language routines thatappear commonly. Rather, it references the FORTRANsubroutine library as necessary.

FORTRAN Patchwork

/ found a few bugs in Radio Shack's FORTRAN editor that were not apparent at first. On the whole, they are minor, such as the inability tostop screen scrolling with "< SHIFT > @". But a rather severe bug exists when index files are created. The editor creates an index file when ex-tremely long source files are written. This helps in loading large source files during subsequent editing sessions. Unfortunately, 1 got "garbage" inmy program source listings when files were augmented by Edit-80-created index files. Killing the index file and loading the source file without itfixed the problem. Your local Radio Shack dealer has two patches to rectify these problems: one for Disk EDTASM (catalog number 700-2210)and one for FORTRAN (catalog number 700-5210). . . . TD

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Running the System

Four steps are required in order to use the system:

1. Writing and editing the FORTRAN program

2. Compiling the source code to relocatable objectcode

3. Linking the object code to memory and creating acommand file

4. Executing the program

One particularly nice feature of the compiling process isthat it will, at your request, not only create an object file,but also an assembly-language listing of your program.It's a great way to learn how your computer "thinks"FORTRAN. One other advantage of the package also ap-pears at the time of compilation. If you wish, you cancompile the source code down to machine code that issuitable for loading into ROM (read-only memory).To check for syntax and other errors in your FOR-

TRAN program, you can compile the code withoutcreating the object file on disk. The compiler runsthrough the program and then displays error and warn-ing messages. Once an error-free object file is created, it islinked. It can then be run immediately or stored as acommand file to run under TRSDOS 2.3. In single drivesystems, the relocatable object file must always be on thedisk containing the linker and FORTRAN library. Conse-quently, free disk space is limited since these two files oc-cupy 25 grans of space.

Benchmarks

If you've never used FORTRAN, you're probably ask-ing, "Why go through all this effort to write and execute aprogram?" The answer is threefold: speed, speed, andspeed! There is no doubt that virtually any problemsolved in FORTRAN could be solved, say, in BASIC. Butunless you enjoy waiting, you should consider FOR-

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Listing 1: Benchmark programs that compare Radio ShackBASIC, an interpreted language, with Radio Shack FORTRAN,a compiled language. The BASIC program (la) took almosttwenty times as long as the FORTRAN program (lb) tocalculate the answer,(la)

100 DE

FDBLC

:,D:DEFINT A,B

105 FORA = 0TO100

110 FORB = 0TO100

115 O

= (AI2)

f(Bt2)

120 D =

= D + C

125 NEXT B,A

130 PRINT TAB(20)D

135 END

(lb)

00100

DOUBLE PRECISION C,D

00105

INTEGER A,B

00110

DO 10 A = 0, 100

00115

DO20B = 0, 100

00120

C = (A**2) + (B"2)

00125

D = D + C

00130

20

CONTINUE

00135

10

CONTINUE

00140

WRITE(5,30)D

00145

30

FORMAT (20X.D15.9)

00150

END

TRAN for "number crunching" applications.

The benchmark that is described here demonstratesthis difference vividly. It consists of nested loops in whichtwo numbers are squared, added together, and thenadded to the previous total. Listings la and lb show theprogram listings. Note that the eight-line BASIC programlooks fairly innocuous: it took 20 minutes, 44 seconds, torun. Once the FORTRAN program was complied andlinked, the command file required only 1 minute, 4seconds, to run. (I also had a chance to run a similar pro-gram using CBASIC 2 running under CP/M. Even thiscompiled BASIC ran about 4 minutes—over three timesas long as FORTRAN.)

However, in terms of total time required, the languagesare fairly comparable. It took me almost 20 minutes towrite, edit, compile, and link the FORTRAN program,whereas the BASIC program occupied about 4 minutes towrite and edit. This won't always be true, for in longer,less trivial programs, FORTRAN will come out aheadevery time. This is particularly true for programs that arereused, since linking and compiling are one-time opera-tions. In such instances the command file will run in justover a minute, whereas the BASIC program will alwaysleave you time to watch the evening news.

Conclusions

• The FORTRAN package is powerful and elegant.

• The price is right. At a little less than $100, this packagecompares favorably to software at three times the cost.

• My biggest complaint is the absence of the complexdata type. No FORTRAN system should be without it.

• If you're tired of long run times and you aren'tchallenged by BASIC anymore (or you just want to ex-pand your programming horizons) this is the package foryou.H

390 October 1981 © BYTE Publications Inc

Circle 149 on inquiry card.

Technical Forum

The Variable-Duty-Cycle Algorithm

Timothy Stryker, Software Technology Inc, Precision RdDanbury CT 06810

Every now and then a novel technique for handlingdata comes to light which, while not immediately ob-vious, is actually very simple and can be used in a widevariety of applications.

One example of such a technique is the use of thelinked-list data structure, which allows the programmerto create ordered sets of entries into which new entriescan be inserted and from which existing entries can beeasily deleted. Another example is the use of semaphores,which have many applications that center around theallocation of resources to sets of processes.

A new technique in this category has recently beenadded to the list. Pioneered by Albert G Love of GeneralDataComm Industries, the technique initiates an event sothat it occurs a specified proportion of the times thatanother event occurs.

Let us call the event that is conditionally initiated the"kickee," and the other event, typically something thatoccurs at even intervals in time or space, the "kickor."Now define three quantities, called the duty-master, theduty-cycle, and the duty-counter. The ratio of the duty-cycle to the duty-master will determine the proportion ofkickee to kickor events. (The duty-counter is a scratchquantity that will ordinarily be initialized, say at power-up, to zero.) Each time the kickor event occurs, we do thefollowing:

duty-counter ; = duty-counter minus duty-cycleif duty-counter is now negativethen do

< initiate kickee >

duty-counter : = duty-counter plus duty-masterend

This procedure may seem sufficiently abstract as to betotally useless, so let's consider a concrete example: aD/A (digital-to-analog) converter constructed of one bitfrom a computer parallel output port, one resistor, andone capacitor. The resistor and capacitor are connectedso as to form a simple low-pass filter, as shown in figure1. Now you can run the BASIC program shown in listing1 on the computer.

Depending on the values of resistance and capacitance,and the speed at which the program executes, the voltageat the analog output point will be a more or less steady3.75 V. By changing the constant in the DATA statementin line 100, any arbitrary voltage between 0 and 5 V canbe obtained.

In this example, the duty-master is the constant 5appearing in line 70, the duty-cycle is the variable V, andthe duty-counter is the variable C. The kickor is theoccurrence of a pass through the loop extending from line30 to line 90, and the kickee is the decision to output a 1,

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October 1981 © BYTE Publications Inc 391

Technical Forum,

Listing 1: This BASIC program uses the VDC algorithm to pro-vide a steady output voltage when combined with the simplecircuit in figure 1. A change in the value of the DATA statementwill alter this voltage. Program line 80 must output the contentsof B to the appropriate output port.

10 c = o

20 READ V

30 B = 0

40 C = C-V

50 IF C> = 0THEN 80

60 B = l

70 C = C + 5

80 < output B to port>

90 GOTO 30

100 DATA 3.75

FROM I—v.BIT 0 >—^OF COMPUTERPARALLEL DATAOUTPUT PORT

ft?

J—^ ANALOG

'— OUTPUT

Figure 1: Low-pass filter that converts the digital output of thesingle-bit data port to an analog signal.

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instead of a 0, to the port. The utility of this examplecould be considerably enhanced through the use ofassembly language and real-time interrupts, but theutility of the basic scheme should be clear: assuming thateach pass through the loop requires the same amount oftime, the waveform output to the port will have anaverage duty-cycle precisely equal to the ratio betweenthe duty-cycle, V, and the duty-master, 5. In addition,the waveform will bounce back and forth between 0 and5 V at the maximum possible rate given the desired dutycycle and the available processing time, which will makethe low-pass filter's job as easy as possible in reducingripple at the analog output.

The variety of ways in which this same basic techniquecan be applied is extraordinary. Consider the case inwhich two integer quantities need to be kept as close to agiven ratio as possible while both are gradually increasedfrom zero to some higher number. Normally this wouldinvolve substantial amounts of multiplication and/ordivision, or have drawbacks in terms of either minimumincrement size or worst-case error. However, use of theVDC (Variable-Duty-Cycle) algorithm makes the taskstraightforward: simply call the two integers I and J, andlet the desired ratio between them be K:L. Pick a number,M, which is greater than or equal to both K and L, and,each time you wish to increase I and/or ] by a smallamount, do the following:

C := C-Kif C<0then do

< increment I >C := C + M

end

D := D-Lif D<0then do

< increment J>D := D + M

end

This process, of course, merely combines two instancesof the VDC algorithm, using a common duty-master, M.The duty-cycle quantities are K and L, the duty-countersare C and D. The method requires virtually no processingtime or memory space, is completely processor- andlanguage-independent, and presents no theoretical limita-tion on the degree of precision with which the desiredratio may be maintained.

Technical Forum is a feature intended as an interactivedialog on the technology of personal computing. The subjectmatter is open-ended, and the intent is to foster discussion andcommunication among readers of BYTE. We" ask that all cor-respondents supply their full names and addresses to be printedwith their commentaries. We also ask that correspondents supplytheir telephone numbers, which will not be printed.

392 October 1981 © BYTE Publications Inc

Circle 368 on inquiry card.

Nothing that we have seen so far suggests that theduty-cycle quantity could not vary from one occurrenceof the kickor to the next. This is very handy for, amongother things, modeling the effects of acceleration andvelocity upon the position of an object. Suppose we aredesigning a real-time graphics game in which there will bea cannon capable of launching a projectile on a parabolicpath toward a target. Is it possible to generate a parabolicpath without resorting to a multiplication routine?Indeed it is!

We accomplish this by treating the projectile's horizon-tal and vertical velocity components as duty cycles,where the common kickor is a routine that runs at evenlyspaced intervals in time, and the kickees are routines thatmove the projectile one cell horizontally and one cell ver-tically. Typically, the projectile's horizontal velocitycomponent is a constant in the forward direction, and iseasy to handle using the formula we have seen here. Todeal with the possibility that the projectile could, ver-tically, be moving either up or down, we will have to in-troduce the concept of a negative duty-cycle. If M is theduty-master, H and V the horizontal and vertical duty-cycle/velocities, and C and D the duty-counters, thekickor routine looks like this:

C := C-Hif C<0then do

< move projectile one cell to the right >C := C+M

end

D := D-Vif D<0then do

< move projectile one cell up >D := C + M

endelse if D> =Mthen do

<move projectile one cell down>

D := D-Mend< decrease V by a fixed amount >

Photo 1 shows the set of projectile positions that areobtained when M is 125, H is 25, and V starts off at 75and is decremented each kickor pass by 1 until it reaches-75.

More complex (but perhaps less useful) patterns can begenerated if the kickee is permitted to change the value ofthe duty-cycle or duty-master, if the kickee of one VDC ismade the kickor of another, and so on. But even in thesimple forms given here, the applications of thisalgorithm range from data-communications multiplexingto printer/plotter control to industrial process simulationto—who knows what? Perhaps you will be the next toadd to the list. ■

Photo 1: The VDC algorithm can be used to predict theparabolic path of a projectile without the use of multiplicationor division.

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October 1981 © BYTE Publications Inc 393

Technical Forum

Dynamic Simulation in BASIC

S J Houng

c/o BYTE Publications Inc

POB 372

Hancock NH 03449

If you plan to parachute out of an airplane, you maywant to know the terminal velocity of the open chute. Ifyou are an amateur rocket launcher, you may want toknow what orbits can be obtained from a prepro-grammed multistage rocket. Answers to these questionscan be quickly obtained from a personal computer pro-grammed in BASIC.

In general, dynamic systems can be represented by aset of ordinary differential equations, such as thoseshown in the figures. The solution can be found by com-puter simulation using numerical analysis. We will useEuler's method to solve a set of differential equations.

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Euler's method states that for a given first-order equa-tion

$ = fit.x)at

the solution can be obtained by the following routine:xB+1 = x„ + hf(t„, x„)

where:

f„+l = r„ + hn = 0,1, 2,

The solution x„+1 at the time £„+1 can be calculated fromthe previous solution x„ at f„. Therefore, the completesolution can be found, step by step, from the given initialcondition x0 at f0. The parachuting problem in figure 1can be solved, in BASIC, by repeatedly using the follow-ing statements in a BASIC program:

V = V + H*(G-T=T + H

■D*V*V/M)

Begin with the initial velocity V and time T.

Euler's method definitely solves first-order equations.But how about the second-order equations in figures 2through 4? We need a magic (mathematical) transforma-tion here. For a given second-order equation:

cPx .dt2

A<k + Bx

dt

if x, = x and x2 = dx/dt, we obtain the followingsimultaneous first-order equations:

dxjdt

dxjdt

= X2

F -Ax2 —Bxj

The above equations are mathematically equivalent tothe original second-order equation. Euler's method can beapplied to solve them in BASIC as follows:

394 October 1981 © BYTE Publications Inc

Circle 223 on inquiry card.

Circle 380 on inquiry card.

F1 = H*X2F2 = H*(F-A*X2-X1=X1 + F1X2 = X2 + F2T=T + H

■B*X1)

Start with the initial conditions XI and X2 at T.

This magic transformation can be easily extended tothe nth-order equation. The result is a set of nsimultaneous first-order equations that can be solved byEuler's method.

This same transformation can also be applied to themoon-landing and rocket-launching problems in figures 5and 6. Each second-order equation produces two first-order equations. The result is a set of four simultaneous

v = velocityM = massD = dragg= gravity.

dvdt

= 9

M

Figure 1: Determining the terminal velocity of a mass descend-ing by a parachute requires solving a first-order differentialequation. Computers can solve this equation using Euler'smethod.

x = displacement

W = massK = spring

d2x B dx + l£x _dt2 M dt M

f

M

S = friction

1= force

Figure 2: Solving the second-order differential that describes adynamic mass-spring-friction system requires transforming thesecond-order equation into two simultaneous first-order equa-tions and applying Euler's method.

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Technical Forum

first-order equations for each problem. For example, inthe rocket-launching problem, if x,=R, x2 = dR/dt,x3=d, and x4 = dd/dt, we obtain:

dt

*** = -^sin0 - g + xt(x4ydt M

dxj =dt

X4

4& = 1-COS4, —?-(Xi)(X4)

dt M *i

Y7ZZ7} CLAMPED

0 = angular displacementJ = moment of inertiaK = spring8 = friction7" = torque

cP8 B_ d0 , K_e _ _Tdt1 J dt J " J

Figure 3: Euler's method can also be applied to the second-orderdifferential equation of a rotational system.

q = charge/ = currentv = voltageR = resistanceL = inductanceC = capacitance

Oft

<£9 + B-^£ + _S_dt2 L dt LC

Figure 4: This RLC (resistive-inductive-capacitive) circuit isdescribed by both first-order and second-order differential equa-tions.

396 October 1981 © BYTE Publications Inc

Circle 287 on inquiry card.

Circle 241 on inquiry card.

The corresponding BASIC programming is:

F1 = H*X2

F2 = H*(T1*SIN(P1)/M-G + X1*X4*X4)

F3 = H*X4

F4 = H*(Tl*COS(Pl)/M-2*X2*X4/Xl)

X1=X1 + F1

X2 = X2 + F2

X3=X3+F3

X4 = X4 + F4

T=T+H

JET 1

ZT

JET 2

x,y = displacementJet1,Jet2 = thrustg = gravity

dt2

dt2 y

Jet1M

Jet2M

Figure 5: Euler's method can be applied to a moon-landingsimulation, solving the four simultaneous first-order equationsderived from two second-order differential equations.

R = radial displacement

= raaiai displacement ^2_ /d»V j

- angular displacement —^ R \3T) = Xf S'n*

= mass \ /

2 / cot V / ae \ _ _r

R\dt J\dt J M

M = mass

g = gravity

T= thrust

0 = turnover angle

cffldt2

COS 0

Figure 6: Solving this rocket-launch simulation involves apply-ing Euler's method to four simultaneous first-order differentialequations.

reformaTTer

©MicroTech E«oorts 1980

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October 1981 © BYTE Publications lnc 397

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Technical Forum,

Listing 1: A BASIC program that uses Euler's method for solvingdifferential equations. The example is used to solve the two first-order differential equations derived from the mass-spring-friction system in figure 2.

1 REM MASS-SPRING-FRICTION SYSTEM

5 H = 0.1

10 PRINT"FRICTION B/M = ",

20 INPUT B

22 IF B<0THEN END

24 PRINT'NO. OF DATA = ",

26 INPUT N

30 XI =0

40 X2 = 0

50 T = 0

60 FOR 1=1 TON

70 FOR I = 1 TO 2

80 F1=X2

90 F2 = 1-B*X2-X1

100 X1=X1+H*F1

110 X2 = X2 + H*F2

120 T = T + H

130 NEXT J

140 PRINT"T = ";T,"X1 =

';X1,"X2 =

';X2

150 NEXT I

160 GOTO 10

FRICTION B/M = ? 0.4

NO. OF DATA= ? 10

T= .2 XI =

.01

X2 =

.196

T= .4 XI =

.058316

X2 =

.372714

T= .6 Xl =

.140785

X2 =

.524336

T= .8 XI =

.252147

X2 =

.646391

T= 1 Xl =

.386318

X2 =

.735829

T= 1.2 Xl =

.536677

X2 =

.791063

T= 1.4 Xl =

.696359

X2 =

.811945

T- 1.6 Xl =

.858536

X2 =

.799682

T= 1.8 Xl =

1.01669

X2 =

.756717

T= 2 XI-

1.16484

X2 =

.686553

FRICTIONB/M= ? -9

Starting with the initial location (R,d) and velocity(dR/dt, dd/dt), the launching orbit can be calculated withthe turnover function <f>(t) and the multistage rocket-thrust function T(r).

One question remains. What value of h should be usedin Euler's method? The h is the time increment (or stepsize) of the computation. Based on the numerical analy-sis, h must satisfy the following stability condition:

h <

df(t,x)dx

to have a stable numerical computation. The computedsolution approximates the exact solution if the value of his chosen according to the stability condition; otherwisethe computed solution may not be a solution at all. Inpractice, we have to use the maximum estimated value ofthe partial differentiation | df/dx | in the stability condi-tion. This guarantees a stable computed solution for all

398 October 1981 © BYTE Publications Inc

Circle 421 on inquiry card.

Let's try Euler's method on the mass-spring-frictionsystem shown in figure 2. The analytic solution of thesystem is well known. Thus, we can use this computerexample as a test for the accuracy of Euler's method.Assume the following data:

forcing function

spring/mass ratio

L

M

k_M

1, for f > 00, for r < 0

friction/mass ratio 0 < — < 10

M

and the initial conditions, x(0) = 0 and dx(0)/dt = 0 atf = 0. The equivalent simultaneous first-order equationsare:

dx, _ _ f

<**> = 1 --^-x2

dt M

The partial differentiations are:

Xi

dJl = 0 and dJl =dxi dxi

B_

M

Thus, we should choose step size h according to thefollowing conditions:

h2 <

K <

dx.

< oo

dJl

dxi

U)

= 0.2

where hx < co indicates a don't-care case. Therefore,h = hi<0.2 is the only guideline we have to follow. Let'schoose h = 0.1. The BASIC program is shown in listing 1.You specify the B/M value, and the solution is printedout immediately.

You now have a powerful computer tool for solvingordinary differential equations of the nth order. Mostengineering problems are represented by ordinary dif-ferential equations. You can sit down and relax now; letyour computer do the engineering design work.B

Reference

1. Carnahan, B, H A Luther, and J O Wilkes. Applied NumericalMethods. New York: John Wiley & Sons Inc, 1969, pages 344through 365.

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Build a Versatile KeyboardInterface for the S-100

David R Richards

c/o BYTE Publications Inc

POB 372

Hancock NH 03449

One of the first decisions you con-front as the builder or purchaser of amicrocomputer is how to com-municate with it. There are three op-tions:

• Use the front panel (if one exists).This is so slow, awkward, and error-prone that it merits no further discus-sion.

• Interface a video terminal orteletypewriter to the computer, usual-ly by means of a serial I/O (in-put/output) port. This solution iseasy to implement, but is often quiteexpensive.

• Interface a keyboard to the com-puter for input and use a videodisplay processor driving a televisionmonitor for output. Since it uses theintelligence of the microprocessor in-stead of duplicating it, this method islower in cost and superior in flexibili-ty when compared to a stand-aloneterminal.

One goal in building my S-100system was the development of hard-ware and software to provide all thecapabilities of an intelligent text-editing terminal that could be used tocommunicate with a mainframe time-sharing system. The third alternativewas clearly the way to go. Idiscovered that while suitable videoprocessors are readily available,keyboards are more of a problem.The only one I found was a surpluskeyboard unit.

The keyboard I chose wasmanufactured by Clare-Pendar. Thisand very similar keyboards areavailable from several sources. It willoutput the full 7-bit ASCII character

set and has both a normal shift lockand an uppercase lock that affects on-ly the alphabetic characters and a fewspecial characters—putting thekeyboard into a 6-bit ASCII or TTYmode. It generates a positive-goingstrobe signal whenever a character-generating key is pressed. Severalspecial function keys are provided,including Repeat and Break keys;however, these keys only groundtheir associated output lines. Thekeyboard uses a MOS (metal-oxidesemiconductor) encoder device andrequires -12 VDC and +5 VDC.

Keyboard Interface

There is a significant reason why astandard parallel I/O board cannotprovide an adequate interface to thiskeyboard. A standard handshakingparallel-input port issues a busysignal when it is waiting for the pro-cessor to accept a character in its buf-fer. If a keyboard that does not havea busy input outputs anothercharacter during this time, the con-tents of the input buffer will bechanged. In most systems, this doesnot actually occur, since the pro-cessor has no trouble keeping up witha human operator. However, in aninterrupt driven real-time system, thekeyboard input process may bepreempted by a higher-priority pro-cess and thus may be unable to han-dle characters as fast as they aretyped. In such a circumstance, thekeyboard must be locked out until theprocessor is able to accept input;otherwise, characters will be skipped.

The inverse problem is more likelywhen mating a surplus keyboard to amicrocomputer: if the key signal lasts

longer than it takes the processor toread a character in the buffer, thischaracter will be read over and overuntil the signal terminates. Both ofthese problems are avoided if thebusy signal clears the key signal im-mediately and blocks any subsequentkey signals until the processor readsthe character. Since most keyboardsdo not provide such a facility, it mustbe provided by the interface.

Since my Clare-Pendar keyboardhas no on-board repeat oscillator,this must also be included in the inter-face. If the Repeat key is held downwhile any character-generating key ispressed, I wanted that character to berepeated until the key is released.

Finally, I wanted the Break key tobe operational, since some timeshar-ing systems take special action onsensing a Break. Break is not a con-trol character; on a terminal with astandard current loop interface, itopen circuits the current loop as longas it is pressed. For an RS-232C inter-face, Break forces the transmit line toa space condition as long as it ispressed. Thus, it is necessary for soft-ware to sense when the Break key ispressed and released. The serial com-munication interface I use is based ona 6850 ACIA (asynchronous com-munications interface adapter), andthis software outputs the appropriatecode to the device control register tocause a Break (space) level to betransmitted when the Break key isfirst pressed and then resets the con-trol register when the key is released.

For the reasons outlined above, Idesigned and built a special-purposekeyboard interface. It is basically astandard parallel input port, but it

400 October 1981 © BYTE Publications Inc

The keyboard is

addressed as two

adjacent I/O channels;

the control/status

channel is the even

address, while the data

channel is the

odd address.

also handles the busy signal onboard, incorporates a repeatoscillator, allows the processor toascertain the status of the Break key,and provides both +5 VDC and-12 VDC to the keyboard. I alsodecided to make provision for con-necting a paper-tape reader in placeof the keyboard in order to load soft-ware supplied on that medium (rarethough it is these days).

Software Interface

The keyboard is addressed as twoadjacent I/O channels; the control/status channel is the even address,while the data channel is the oddaddress. Any pair of addresses maybe chosen by appropriate strapping oftrue or inverted Al through A7 ad-dress lines to the inputs of IC10 (seefigure 1). The true address signal isused if the corresponding bit in thechosen address is a 1 and the invertedsignal is used if the bit is a 0.

Output to the control/status chan-nel is used to enable or disable inter-rupts from the interface. If bit 0 is a 1,interrupts are enabled; if it is a 0, in-terrupts are disabled. The rest of thebits are ignored. Interrupts are alsodisabled when power is first applied.If enabled, an interrupt signal isgenerated whenever a character isoutput by the keyboard and isavailable to the processor, or whilethe Break key is pressed. This signalmay be strapped to the inter-rupt line ( INT ) or any of the

vectored interrupt lines ( VIO - VI7 )if a vectored interrupt controller isused.

Input from the control/status chan-nel enables the processor to read thekeyboard status register. Bit 0 is a 1whenever an interrupt would be

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.22

74LS132

.22

74LS136

.45

741 SI 3!

.40

74LS13S

.35

74LS15'

.18

74L.S1K

.18

74LS155

.26

74LS19

.35

74LS157

.28

74LS151

74LST&

.18

74LS1S'

35

74LS162

.30

74LS15:

.30

74LS1&

.40

74LS1S

.44

74LS15!

.65

74L517I

20

7-1LS172

.20

74LS17

74LS17

.35

74LS18

.36

74LS19

74LS19

.75

74LS192

.85

74LS19:

40

74LS1W

.45

74LS19'

74LS196 - 8574LS197 - B574LS221 - B074LS240 - 9574LS241 - 9574LS242- .9574LS243 - 1.0074LS244- 1.3574LS245 - 1.5074LS247 - 7574LS248 - 1 1074LS25I .9074LS253 - 5574LS257 - 7074LS25B - .6074LS259 - 1 5074LS266 - .4574LS273 - 1 1574LS279- .5074LS2S0 - 1.8074LS290 - .7574LS293 - 40

7JLS373 - I.3C74LS374- 1.3574LS377 ~ l.-K74LS386 - H74LS390- 13!74LS393 - 1.2!74LSG70 - 2 5/H1LS97 - 1.1181LS9U -1.1

LINEAR CIRCUITS

MAN 82 C-A. Yellow. $ .75

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LM339 - 65

LM34B -LM358 -LM361 -LM377 i.hjLM380 - 1 2&LM382 - 80LM383 - 2 50LU386 - .80LM387 - 1.26LMS53 - 2 25LM6&5 - .45LM55G - .85564H -3.95

733 -

lmih

9 - 1.9!CA758 - 1 75CA3018 1.9!CA3046 - .85CA3078 ■ 1.HCA3080 - 95CA3086 - .95CA3094 - 2.2!LM2801 ■ 96B03BCC - 3.91N5590A - 1

REGULATORS

LM317T .... .SI .50

LM337 S2.50

323K-5V3A S4.50

79HGKC 5Vsl5A S6.95

78L05 5 .45

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October 1981 © BYTE Publications Inc 401

+ 5V

keypressed| ^>

0.01/iF

IC1774LS14

Figure 1: Schematic diagram for the S-100 keyboard interface. The address jumpers shown are for channels 0 and 1. Keypressed andbusy signals may be active high (+ jumper) or active low (— jumper). If a vectored interrupt board is used, the interrupt signal maybe jumpered to the processor interrupt line (INT) or any of the vectored interrupt lines (VIO through VI7). The interrupt sig-

402 October 1981 © BYTE Publications Inc

DO 01 D2 D3 D4 D5 D6

nal should be left unconnected if interrupts are not used. Data line D7 should be connected to ground inside the keyboard cable25-pin plug. If a paper-tape reader is connected in place of the keyboard, D7 is used for the high-order data bit. (See power connec-tions on page 404.)

October 1981 © BYTE Publications Inc 403

Number

Type

+ 5 V

GND

IC1

74LS27

14

7

IC2

74LS74

14

7

IC3

74LS74

14

7

IC4

555

8

1

IC5

74LS14

14

7

IC6

74LS14

14

7

IC7

74LS74

14

7

IC8

74LS00

14

7

IC9

74LS04

14

7

IC10

74LS30

14

7

IC11

74LS04

14

7

IC12

74LS175

16

8

IC13

74LS175

16

8

IC14

7406

14

7

IC15

74LS02

14

7

IC16

74LS132

14

7

IC17

74LS14

14

7

IC18

74LS14

14

7

IC19

8T97

16

8

IC20

8T97

16

8

IC21

LM340T-5

—

—

Power connections for

figure 1.

Listing Is A keyboard device handler for an 8080-based system. Utilizing program I/O,this routine returns with a 0 flag set if no character is available or the carry flag set if theBreak key is pressed. If neither condition is true, the character is returned to theaccumulator.

generated if enabled, making possibleprogram input/output.

When a character is available, theprocessor reads it with an input fromthe data channel. Output to the datachannel has no function.

The keyboard generates only 7 bitsof data, so the high-order bit 7 of thedata channel is used to indicate thestatus of the Break key; it is a 1 whilethe Break key is pressed.

A simple keyboard device handlerfor an 8080-based system is shown inlisting 1. It is written so that the call-ing program can decide what to do ifno character is available. In that case,the routine returns with the 0 flag set.If the Break key is pressed, theroutine returns with the carry flag set.If a character is available, neither flagis set, and the routine returns with thecharacter in the accumulator.

Listing 2 shows a fragment of a ter-minal emulator program that inputscharacters by calling the keyboarddevice handler, loops until acharacter is available, and takes ap-propriate action when the Break keyis pressed.

Circuit Description

A schematic for the interface isshown in figure 1. All logic, exceptthe 8T97 bus drivers, the 7406 inter-rupt and Busy driver, and the 555

; KEYBOARD STATUS CHANNEL

;KEYBOARD DATA CHANNEL

;INPUT KEYBOARD STATUS

;IF NO CHARACTER AVAILABLE, RETURN WITH

;ZERO FLAG SET, CARRY FLAG CLEARED

;INPUT KEYBOARD DATA

;IF BREAK KEY DEPRESSED,

;RETURN WITH CARRY FLAG SET,

;ELSE RETURN WITH CHARACTER IN

;ACCUMULATOR

Listing 2: Example program using keyboard input. This is a fragment of a terminalemulator program which reads characters from the keyboard by calling the keyboarddevice handler and looping until a character is available. It also takes the appropriateaction when the Break key is pressed.

KBSTAT

EQU

0

KBDATA

EQU

KBSTAT + 1

KBD:

IN

ANI

RZ

KBSTAT1

IN

KBDATA

RAL

RC

RAR

RET

LOOP:

BREAK:

BREAK 1:

CALLZC

MP

CALLC

MP

KBD

LOOP

BREAK

LOOP

KBDBREAK 1

LOOP

;WAIT FOR CHARACTER FROM KEYBOARD;GO HANDLE BREAK;PROCESS CHARACTER

;ASSERT BREAK CONDITION

;WAIT FOR BREAK KEY TO BE RELEASED

;CLEAR BREAK CONDITION

repeat oscillator, is low power Schot-tky (74LS). All keyboard and bus in-puts have hysteresis receivers (74LS14or 74LS132 Schmitt triggers) for max-imum noise immunity. Bus inputs seeonly a single 74LS load.

When the keypressed line goes ac-tive (high or low, depending on howit is strapped), the Keypressed-Strobeflip-flop is set, clocking a characterinto the data latches (ICs 12 and 13)and setting the Data-Available flip-flop. The Data Available signal thenclears the Keypressed-Strobe flip-flopand holds it cleared until the pro-cessor has read the character. Mean-while, any further Keypressed signalsare prevented from changing the datain the latches. No conditioning is pro-vided for the keypressed line since mykeyboard generates a clean Key-pressed Strobe.

If the repeat line is low when thekeypressed line goes active, H-3 goeslow, setting the Repeat-Enable flip-

flop. The repeat oscillator then canclock the Repeat-Strobe flip-flop,which in turn sets the Data-Availableflip-flop. The Data Available signalclears the Repeat-Strobe flip-flop andholds it cleared until the processorhas read the character in the datalatches. The cycle then repeats ap-proximately 10 times per second, sothe character in the data latches isread over and over. When the repeatline goes high, the Repeat-Enable flip-flop is cleared so the oscillator can nolonger set the Data-Available flip-flop. Contact bounce when theRepeat key is initially pressed reallydoes not matter, hence the repeat lineis not conditioned.

If an input or output operation ismade from or to the board, F-8 goeslow, causing G-4 to go high if the(odd) control/status channel isselected and causing G-l to go high ifthe (even) data channel is selected.

If the control/status channel is

404 October 1981 © BYTE Publications Inc

selected, coincidence of PDBIN andSINP causes H-8 to go low, enablingthe status drivers so the processor canread the state of the Data-Availableflip-flop. Coincidence of PWR andSOUT causes G-13 to go high, clock-ing DOO into the Interrupt-Enableflip-flop.

If the data channel is selected, coin-cidence of PDBIN and SINP causesH-ll to go low, enabling the datadrivers so the processor can read thelatched-keyboard data. The trailing(rising) edge of this signal also clocksa 0 into the Data-Available flip-flop,clearing it.

The Break signal, after condition-ing, is ORed with bit 7 of the datalatch IC12. The keyboard generatesonly 7 bits of data, so bit 7 is strappedto ground inside the keyboard con-nector plug and the processor inter-prets bit 7 as the Break key. TheBreak signal is also ORed with theoutputs of the Keypressed-Strobe andRepeat-Strobe flip-flops and hence,like them, can set the Data-Availableflip-flop.

If a paper-tape reader is connectedin place of the keyboard, the Breakinput is left unconnected so that bit 7is used for data from the reader. Thetrue or inverted Data Available signalis also available on the busy line T-6to allow a conventional handshakinginterface with the reader.

If the Interrupt-Enable and Data-Available flip-flops are both set, theoutput T-12 of the interrupt busdriver goes low.

The Power-On Clear signal (POC)initializes the interface by clearing theKeypressed-Strobe, Repeat-Strobe,Data-Available, and Interrupt-Enableflip-flops.

Construction

I constructed the interface on aProcessor Technology wire-wrapprototype board. This is suppliedwith the LM340T-5 regulator, heatsink, and decoupling capacitors need-ed for the +5 VDC supply. I con-structed a zener-regulated —12 VDCsu'pfly in the discrete component areabelow the heat sink.

Wire-wrap sockets (16-pin) are notsupplied with the board and must beobtained separately. Figure 3 shows

'E>

•15fiF

IC21LM340T-5

/77

75 a

1/2W

1

;0.1/iF

TYPICALFOR 12

>+5V REGULATED SUPPLY

;o.i/*F

X 1N47^^12V1W

ft!

-| ^>-12V REGULATED SUPPLY

Figure 2: Schematic diagram of the interface power supply. The 0.1 nf capacitors on the+ 5 VDC output are ceramic disk despiking capacitors.

recommended component placement,designed to simplify interconnectionsand minimize wire lengths. All pins ofthe lower row of sockets, which pro-vide connections to the bus lines,should be soldered to the board. It issufficient to solder the four cornerpins of the rest of the sockets. Thesockets should be oriented so that,when viewed from the rear (pin) sideof the board, pin 1 is in the upper left-

hand corner, pin 8 is soldered to theground land, and pin 16 is soldered tothe +5 VDC land. Between each pairof sockets, a pair of holes is left, oneconnected to +5 VDC and the otherconnected to ground. These are in-tended for the installation of 0.1 fiiceramic disk bypass capacitors for+ 5 VDC supply despiking. I in-stalled the capacitors at the locationsshown in figure 3. (The disk

THE TS

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Circle 373 on inquiry card.

October 1981 © BYTE Publications Inc

405

0.01/iF

IC174LS27

I

IC274LS74

IC374LS74

100ft-15MF-

•iill» liDii

3U_E

IC574LS14

IC774LS74

•

IC874LS00

IC974LS04

I

I CIO74LS30

ICU74LS04

I

IC1274LS175

/GROUND

IC147406

I C 15

74LS02

IC 16

74LS132

(

IC1774LS14

IC 18

74LS14

•

I C198T97

IC208T97

WIRE WRAP PIN(ON BACK SIDE)

NOTE: CAPACITORS NOTMARKED ARE O.lpFFILTER CAPACITORS.

-15 +15

Figure 3: Component placement for the interface board. The ceramic disk despiking capacitors referred to in figure 2 are shown be-tween the integrated circuit sockets.

Function

Interface

Back Panel

Clare-Pendar

16-Pin DIP

DB-25S

Keyboard Edge

Connector

Connector

Connector

KP

2

1

H

BUSY

15

2

—

DO

3

3

3

D1

14

4

C

D2

4

5

4

D3

13

6

D

D4

5

7

B

D5

12

8

1

D6

6

9

A

D7

11

10

—

REPEAT

7

11

5

BREAK

10

12

E

+ 5 VDC

16

15

9

-12 VDC

1

14

10

GROUND

8

13

8

Table 1: Pinout connections for the cable between the keyboard and the S-100 inter-face board.

capacitors supplied with the boardwere too large to fit between thesockets and I had to use physicallysmaller ones.)

All integrated circuits, regardless ofthe number of pins, are inserted withpin 1 in pin 1 of the 16-pin sockets. Itis then necessary to install a short

wire-wrapped jumper from pin 8(ground) of the socket to pin 7 for14-pin circuits and to pin 1 for the8-pin 555.

The discrete timing components forthe 555 oscillator, the pull-upresistors for the repeat and busy lines,and the components for the break lineconditioning circuit are soldered totwo DIP (dual in-line pin) headerplugs as shown in figure 3. Theseplugs are then installed in sockets atthe locations shown.

Connections to the keyboard aremade through a 16-pin socket. I useda 16-conductor flat cable jumper witha DIP plug at one end to connect thissocket to a 25-pin socket (DB-25S) onthe computer's back panel. Table 1shows the pinouts for both sockets. Ithen made up a 6-foot cable with a25-pin plug (DB-25P) at one end anda 20-contact printed-circuit edge con-nector (AMP 582963-2 with 42839-4pins and a 582501-1 polarizing key) atthe other to mate with thekeyboard. ■

406 October 1981 © BYTE Publications Inc

PERT Organization

A Technique for Evaluating Schedules

The acronym PERT stands for Pro-gram Evaluation and Review Tech-nique, a mathematical method usedby thousands of computer program-mers on both large and small systemsto solve one of the basic problems ofmiddle-level managers: how to deter-mine the relative importance of thetasks under their supervision.

Let us define a middle-level man-ager as a person responsible for a pro-ject comprised of many tasks. Vari-ous low-level managers, each respon-sible for one particular task, report tothe middle-level manager. (By con-trast, the top-level manager is moreconcerned with deciding which pro-jects to undertake, and formulatingpolicy.) The basic purpose of themiddle-level manager is to anticipatepossible obstacles and still completethe project on time.

A Typical Problem

In order to more clearly illustratethe middle-level manager's problem,let's be specific and assume that theproject is the construction of the fifthfloor of a seven-story office building.

The project begins with the form-ing and the pouring of concrete. Theprocedure is supposed to take sixdays, but for some reason it takes

W Douglas Maurer

Department of Electrical Engineering

and Computer Science

George Washington University

Washington DC 20052

seven days. Now the project is a daybehind schedule.

At this point, the manager looks atthe various tasks: plumbing, sprayfireproofing, and so on, and notesthat while most of them will requirefrom three to five days, the installa-tion of electrical wiring in the wallwill require sixteen days. Accord-ingly, he hires a few more electri-cians, and the electrical wiring is in-stalled in fourteen days. Now the pro-ject is a day ahead of schedule.

In several ways,the calculation of T2

Is the reverse ofthe calculation of T1

Or is it? After the walls have beenwired, the next step involves the lathand plaster, which can't be starteduntil the insulation has been installed.The insulation requires only threedays, but that can't progress until theelectrical testing has been completed,and that requires three days. Ofcourse, the testing can't begin untilthe ceiling air ducts and fixtures arein, which takes five days...and so onand so on. The upshot is that the pro-

ject is still one day behind.

The problem in this example(taken, as is much of the material inthis article, from Fundamentals ofData Structures, see references) isthat the electrical wiring is not acritical activity (ie: a task that causesthe entire project to slip if it fallsbehind schedule). In fact, in this ex-ample the manager should have hiredfewer, not more, electricians, andallowed the wiring to take as many astwenty-eight days. The extra moneycould have been used to hire morepeople for the spray fireproofing andinstallation of ceiling ducts and fix-tures, which are critical activities.

But how can the manager deter-mine what is a critical activity andwhat is not7 This is where PERTcomes in.

Analyzing Problems with PERT

There are many ways to applyPERT. I will illustrate one simple ap-plication. The first step is to numbereach task, or activity, in such a waythat they can be performed in numeri-cal order. For example, we cannot re-quire that activity number 7 be fin-ished before activity number 4 isstarted, for if this is the case, then ac-tivity number 4 should be designated

October 1981 © BYTE Publications Inc 407

as some number higher than 7. Ifthere are n activities, then theyshould be numbered from 1 to n.

To adapt our scheme to computernotation, we will now set up a two-dimensional array, called B. If we re-quire that for each pair of activitynumbers I and J, I be finished before Jcan start, we set B(I,J) = 1. Other-wise, we set B(IJ) = 0. (If we use aversion of BASIC that does not allowdouble subscripts for arrays, or if we

use assembly language, we canemploy the following trick: set up asingle array A, containing n1elements, where n is the number ofactivities, and then refer to eachB(I,J) array element as A(K), wherewe have assigned K = tiX(I-l)+]before referring to A(K). Thus, ele-ments B(l,l) through B(l,n) arerepresented as A(l) through A(n);B(2,l) through B(2,n) as A(n + 1)through A(2«); and so on.)

©

©

©

©

5 DAYS

Figure 1: Typical project containing ten tasks, or activities. Each task requires a certainnumber of days for completion and can be begun only when the preceding tasks havebeen finished.

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We initialize this double array toall zeros and then input various pairsof numbers I and J, where we want toset B(I,J) = 1 according to the aboverule. We also set up another array T,such that T(I) is the amount of timetaken by activity number I. If T(7)= 5, then activity number 7 takesfive days to complete. (Actually itcould be five weeks, or even fivehours, just as long as the same unitsare used throughout the array T.) Allthe numbers T(I), as I varies from 1 ton, must be entered.

Now we have all the input we need,and we can proceed to calculatewhich activities are critical. We mustfirst set up an array that we will callTl, such that each element Tl(I) is theearliest starting time for the activitynumber I. If Tl(5) = 9, then activitynumber 5 cannot be started before theninth day of the project. (From nowon, we will assume that all times aregiven in days.)

A possible reason why Tl(5) mightequal 9 is revealed in figure 1. Thenumbers in circles are activitynumbers, and we have drawn arrowsbetween activities; all activities linkedby incoming arrows must be com-pleted before the next activity canbegin. Activity number 1 takes fivedays, and activity number 3 takesthree days. If we look only at the up-per part of the diagram, we mightthink that activity number 5 couldstart after eight days. However, if welook at the rest of the diagram, we seethat we have to perform activitynumber 2, which takes four days, andthen number 4, which takes five days,before we can do number 5. Sonumber 5 cannot, indeed, start untilafter nine days.

(One confusion that often arises isthat if a task requires three days, andit is begun, let us say, on Monday,the task should be finished byWednesday. Yet Wednesday is two,not three days after Monday. Thesolution to this paradox is to considera day as a 24-hour period. If a task isstarted at 8 am Monday, and it takesthree days, we consider it to be fin-ished at 8 am Thursday, although inreality it will be finished by 5 pmWednesday.)

408 October 1981 © BYTE Publications Inc

Circle 283 on Inquiry card.

In figure 1, the arrow drawn be-tween activities I and J corresponds toBflJ) = l.ThuswehaveB(l,3) = 1and B(3,5) = 1. It is debatablewhether or not we should set B(l,5)= 1; after all, activity number 1 mustbe completed before activity number5 can begin, but only in an impliedsense. In this case, it does not reallymatter if B(l,5) = 1. In general, re-dundant pairs of activities can eitherbe provided as input or left out; thecritical-activity calculation will comeout the same, regardless.

The calculation of the earliest start-ing time, Tl(I), is performed as Ivaries from 1 to n. At each stage, welook at all B(K, I), for K less than I,such that B(K, I) = 1. If nothing hasto finish before activity number I canstart, then we set Tl(I) = 0, since ac-tivity number I can now clearly startat time zero. In setting up the prob-lem of figure 1, we would set Tl(l) =0 and Tl(2) = 0.

If there is one array element B(K, I)that satisfies the condition above,then we add Tl(K), the earliest timeat which activity K can start, to T(K),the time that activity K takes. Thus,in figure 1, in order to calculateTl(3), we would add Tl(l) and T(l).We find that activity 1 can start attime zero, and it takes five days.Clearly, activity 3 cannot start untilafter five days—that is, Tl(3) = 5. Inthe same way, we calculate Tl(4) =4.

If there is more than one elementB(K, I) that satisfies the condition,then we perform the above calcula-tion several times and choose thelargest answer. Let us calculate Tl(5)as shown in figure 1. We have:

Tl(3) = 5

T(3) = 3

Tl(3) + T(3) =8

and

Tl(4) = 4

T(4) = 5

Tl(4) + T(4) = 9

This is the calculation we made be-fore. One condition is that activitynumber 5 cannot start until after eightdays; the other condition is that ac-

tivity number 5 cannot start untilafter nine days. Therefore, it is theninth-day starting date that is impor-tant. In general, there might be threeor more cases that we have to con-sider, and we take the largest of thecalculations.

The resulting values of Tl(I), for allI, are shown in figure 2. In practicalcases, usually the last activity in theproject is to clean up, and we cannotclean up before we have finished

everything else. In the next calcul-ation, we must assume that the lastactivity cannot be started beforeeverything else is finished. If this isnot the case, we set up a dummy ac-tivity, like activity number 10 infigures 1 and 2. This takes no time atall and ends the project.

If T(I) = J, this does not necessari-ly mean that activity number I mustbegin at time ]. Look at activities 6, 7,9, and 10 in figure 2, and suppose that

©

©

©

©

•

DAYS

►■ •

5 DAYS

1=0

Tl = 4

Figure 2: For each activity in figure 1, Tl (the earliest time that each activity can start)can be calculated according to the scheduled completion times of preceding activities.

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they all start at the times given; thatis, on the eleventh, eighteenth, twen-tieth, and twenty-second days, re-spectively. Now look at activity num-ber 8. It is scheduled to begin on theeighteenth day, but it could also be-gin on the nineteenth day (becausethe task takes three days, and by thetime it is finished we are up to daytwenty-two, which is activity number10—the end of the project.)

We are now ready to start the nextcalculation. This time we are calcul-ating a set of values called T2(I), forall I from 1 to n, but we will calculatethem in reverse order. That is, we willcalculate T2(n) first, then T2(n-1),and so on, and calculate T2(l) last.

To speed up a project,

we must accelerate an

activity that lies on

every critical path

The time T2(I) is the latest time thatactivity number I can end withoutcausing the entire project to slip, Amoment ago we saw that activitynumber 8 could occur on either theeighteenth or the nineteenth day, andit would end on either the twenty-firstor the twenty-second day. ThereforeT2(8) would be 22, because thetwenty-second day is the latest timethat activity number 8 can end.

Before we see how to calculateT2(I), let us see how we can use it. Inour example, we have Tl(8) = 18and T2(8) = 22. What does thismean? It means that activity number8 cannot start before day eighteen,and it must finish by day twenty-two.Therefore, this activity cannot takemore than four days. In fact, it is sup-posed to take three days (T(8) = 3),and it can slip by one day, but notmore than one day (otherwise, the en-tire project will slip). In this case, ac-tivity number 8 is not critical. If itwere scheduled to take four days—that is, if T(8) were equal to 4—thenit would be critical. So as soon as wecalculate T2(I) for all I, we will knowimmediately which activities arecritical.

To calculate T2(I), we look at all

410 October 1981 © BYTE Publications Inc

Circle 329 on inquiry card.

B(I, J), for J greater than I, such thatB(I, J) = 1. If there are no instances(which, under our assumptions, willhappen only for the last activity inthe project, ie: I = n) we set T2(I)equal to Tl(I) + T(I). That is, thelast activity must start by time Tl(I),and it requires time T(I), so it mustfinish by time Tl(I) + T(I) in orderto get the entire project done in theleast amount of time that is consistentwith the data we have provided aboutall its various activities.

If there is one B(I, J) that satisfiesthe condition above, then we subtractT(J) (the time that activity J takes)from T2(J), the latest time that activ-ity J can be finished while keeping theproject on schedule. Since the valuesof T2(I) are being calculated in re-verse order, we can assume that T2(J)has already been calculated. In theproject shown in figure 2, we get thevalue of T2(9) by subtracting T(ll)from T2(ll), because activity 10takes no time, and the answer is 22.We get 72(7) by subtracting T(9)from T2(9), and the answer is 20.

Note what this last answer means.The ninth activity takes two days,and it must be done by day twenty-two. This means that it must start byday twenty. If we look at figure 2, wecan see that this implies that activitynumber 7 must also be finished byday twenty. In the same way, we cal-culate T2(8) = 22.

Finally, if there is more than oneB(I, J) that satisfies the condition,then we perform the above calcula-tion several times and choose thesmallest answer. For example, if wecalculate T2(6) in figure 2, we have:

T2(7) = 207(7) = 272(7) - 7(7)

and:

18

72(8) = 22

T(8) = 3

T2(8) - T(8) = 19

This means that activity number 6must end by the eighteenth day, andalso by the nineteenth day. There-fore, the eighteenth-day deadline is

the one we must heed. We can ob-serve a number of ways in which thecalculation of T2 is the reverse of thecalculation of Tl: we go from back tofront; we look at B(IJ) instead ofB(K,I); we must have J larger than I,instead of K smaller than I; and whenthere are several calculations at oneplace, we take the smallest, instead ofthe largest, of the results.The resulting values of T2(I), for all

I, are shown in figure 3. We can nowlook at T1(I) and T2(I), for all I, andcalculate which activities are critical.As we have noted above, activitynumber I is critical if T2(I) - Tl(I)= T(I); otherwise, it is not. Thecritical activities in figure 3 are num-bers 2, 4, 5, 6, 7, 9, and 10. The non-critical activities are 1, 3, and 8.

We now have the answer to themanager's problem in this case: activ-

©

©

©

©

•

5 DAYS

*■ •

3 DAYS \

• *■ •

> 2 DAYS 2 DAYS \

T1 = 0

Tl = 5 \

/ Tl=18 Tl=20 \

T2 =6

T2 = 9 \

/ T2= 20 T2 = 22

\®

©/

Q

\©

y 2 DAYS

7 DAYS

3 DAYS

0 DAYS

/ Tl=9

Tl =11

Tl =18

Tl = 22

/ T2 = ll

T2 =18

T2 =22

T2= 22

Q

O/

4 DAYS

5 DAYS

Tl = 0

Tl = 4

T2= 4

T2 = 9

Figure 3: T2 (the latest time that each activity can be finished without throwing the en-tire project behind schedule) can be calculated for each activity in the project of figure 1.

trauonsj todlcs, tn

Dic?noNAS|

October 1981 © BYTE Publications Inc 411

ities 1, 3, and 8 should not be ac-celerated because they will not affectthe project's completion time. On theother hand, any one of these three ac-tivities could slip by one day withoutaffecting completion time. (In fact,activities 1 and 8, or activities 3 and8, could both slip, but not both activ-ities 1 and 3.)

The critical activities can all be seento lie on one path from the beginningto the end of the project. This is calleda critical path. In general, there mightbe more than one critical path in aproject. If an activity is critical, itcannot slip without affecting projecttime—that is, if it is on a critical path.On the other hand, speeding up anyone activity will not speed up the en-tire project unless the accelerated ac-tivity is on every critical path.

Machine Coding Considerations

If the total number of activities isso large that we cannot fit all of thearray elements B(I, J) into the numberof available words of memory, wemay use the following trick. Sinceeach element B(I, J) is either 0 or 1(such a matrix B is often called aboolean matrix), we can put each ele-ment into a single bit of a memorylocation. On an 8-bit machine, work-ing in assembly language, we wouldrepresent B(I, J) by first dividing J by8 and obtaining a quotient of K and aremainder of L. We would then storeB(I, J) in the Lth bit of B(I, K), and thedimensions of B would now be n byn/8 instead of n by n.

To accomplish this representation,we use an auxiliary table P, such thattable element P(l) is the zeroth bit

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(from the right—ie: in the binarynumber's units bit), element P(2) isthe first bit (ie: the number's 21 bit),P(3) is the second bit (ie: 22 or 4), andso on. We can set up this table by set-ting P(l) = 1 and then P(I + 1) =2XP(I) for I = 1 to 7. To set the Lthbit of X, we perform the logical OR ofP(L + 1) and X, and store it in X; totest the Lth bit of X, we perform thelogical AND of P(L + 1) and X, andtest the zero status flag. On a 16-bitmachine, we do the same analysis,substituting 16 for 8.

In integer BASIC, even on an 8-bitmachine, each integer is customarilystored in 16 bits. If the logical ANDand OR functions are not available inthe given dialect of BASIC, or bymeans of standard library functions,then we can test the Lth bit of X byadding it to itself (that is, shifting it 1bit to the left) N —1-L times, andseeing whether or not the result isnegative. We can set the Lth bit of Xby adding P(L + 1) to X, providedthat we know this bit is not set (bytesting it as above).

Exploring Further

Further analyses of critical paths orcritical activities will be found in EllisHorowitz and Sartaj Sahni's Fun-damentals of Data Structures. Theseauthors describe two graphicalmodels of a project—the AOV (activ-ity on vertex) model, in which eachvertex of a graph like figure 1 cor-responds to an activity, and the AOE(activity on edge) model, in which anactivity corresponds to an edge, orarrow between nodes. The critical-path algorithm given there is actuallyfor the AOE model, whereas the one Igive here is for the AOV model. Theauthors also provide a discussion ofan algorithm (called topological sort)which can be used to renumber all theactivities if the numbering that is useddoes not satisfy our fundamental pro-perty of carrying out all activities inthe project in their numerical order. ■

Reference

1. Horowitz, Ellis and Sartaj Sahni. Fun-damentals ot Data Structures. RockvilleMD: Computer Science Press, 1976.

412 Oclober 1981 © BYTE Publications Inc

Circle 377 on inquiry card.

Should the DO Loop Become anAssembly-Language Construct?

Glenn L Williams

Gould Inc

Instruments Division

3631 PerkinsCleveland OH 44114

The 1970s saw the inception andgrowth of microprocessors as well ascontinuing growth and improvementin the architecture and processingpower of minicomputers. Althoughthe architecture of CPUs (central pro-cessing units) has varied widelythrough the years, the majority of thenew 16-bit microprocessors haveemulated, to various degrees, thestack-pointer architecture once foundin the DEC (Digital Equipment Cor-poration) PDP-11.

The stack pointer is used to controlan area in program memory wheretemporary data and subroutine- andinterrupt-return addresses can bestored separately from the main pro-gram. The stack-pointer approachhas proved useful to programmers be-cause it allows reentrant, nonself-modifying subroutines. This ap-proach can be contrasted with ma-chines (e.g., the DEC PDP-8) where asubroutine return address is saved inthe first location of the subroutineproper, which can reside only in pro-grammable memory.

An additional feature now found inmost processors is the familiar pro-cessor-status register containing flagbits formed from the result of ALU

About the Author

Glenn L Williams is a Senior Design Engineerfor Gould Inc Instruments Division. Currently,he is designing hardware and software for anew line of digital oscillographic recorders. MrWilliams has worked with microprocessorssince the early 1970s. His personal interests in-clude amateur radio and astronomy.

(arithmetic logic unit) operations ondata. With conditional branch, jump,jump to subroutine, and return (aswell as interrupt) instructions avail-able on the various processors, pro-gram loops can become very compactand intricate.

A well-designed instruction set cangive the engineer and programmerevery degree of freedom and everyfeature desired. But does it?

An Example

Take the case of the assembly-lan-guage program in which a positivebinary word in memory is requiredfor the next sequence of instructions.But for various reasons (known onlyto the programmer), the word mayinstead be stored as a negative value.

In the Motorola 6800, Fairchild F8,and even the Motorola 68000 micro-processors, such a value must beloaded and tested for positive status.If negative status results, the datamust be complemented via a branchto the proper code before returning tonormal program execution. There hasbeen one processor available for sometime, however, that performs the ab-solute-value conversion with a singleinstruction: Texas Instruments'TMS-9900.

Obviously, there are other instruc-tions that could make programmingtasks far simpler. Disregarding for amoment the desire of manufacturersto minimize microcode requirementsto limit the size of silicon wafers, and

the argument that some missing in-structions can be "worked around"through use of other instructionchains, it is obvious that highly in-novative and useful instructions canstill be invented by clever users anddesigners of computers. Users stillneed more innovative instructions tohelp relieve the monumental pro-gramming requirements of the 1980s.(After all, where would computers beif architecture development stoppedwith the invention of the subroutineand the carry bit?)

The following discussion will showhow one set of "new" instructions (oracceptable variations) can be foundscattered, piecemeal, in a number ofexisting modern processors, but thatno one processor supplies the userwith the entire set. In particular, thefirst new instruction, requiring mere-ly a modified stack pointer, has yet tobe found in a survey of a number oflate-model processors. This instruc-tion, along with its mate, allows as-sembly-language programming ofDO loops.

"New" Instructions

For the discussion of these instruc-tions shown in conceptual form intable 1, I ask the reader to assumethat the processor has at least onestack pointer, one or more accumula-tors, and, perhaps, additional mainregisters. This model, in figure 1, re-sembles the architecture of thePDP-11 and 6800.

October 1981 © BYTE Publications Inc 413

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Mnemonic Function

DO n The address of the instruction following this one (PC + 2) is saved on

the DO stack, along with the loop-counter value n. The DO loop willthen begin at the instruction following this one (at PC + 2). (See figure 2.)

NXT The ending instruction of a DO loop. In the DO construct, the value

n is decremented and tested for 0. If n does not equal 0, the execu-tion is resumed at the location saved in the DO stack. If n doesequal 0, program execution continues at the next instruction afterNXT. DO loop nesting is permitted by virtue of stack control.

ABS N Converts binary value at effective address N to absolute binary

value and stores it back in N or in an accumulator. Processor-status-word flag is set if value was originally positive.

ASC N Converts a 4-bit binary value at effective address N to its ASCII

equivalent (0 through F).

BIN N Tests a value at effective address N to see if it is a legal hexa-

decimal ASCII character symbol (0 through F). If it is, the characteris converted to the 4-bit binary equivalent. If it is not, a processorstatus flag is set and conversion does not occur.

SRCH n, M Searches for the word or character n in a page of memory begin-

ning at effective address M until either the first occurrence of thatcharacter or end-of-page. (Page size fixed at some value.) If thesearch fails, a processor status flag is set. If the search succeeds,the location of the character is saved in a temporary register.

SRCH n, - M Similar to above, but search proceeds in a negative direction from

effective address M to end-of-page.

Table 1: Innovative and useful instructions, some of which are now available tomicroprocessor users, These instructions are not all available on any one processor.

It is interesting to consider howthese instructions have been imple-mented in various processors. Thesedata are shown in table 2. The seveninstructions listed are not to be con-strued as the only instructions eligiblefor consideration. They are presentedas thought-provoking examples.

The DO Loop Instructions

Frequent use of nested executionloops (DO . . . CONTINUE loops inFORTRAN, FOR . . . NEXT loops inBASIC) raise the question: Why notallow a DO loop construct in assem-bly language (i.e., in the architectureof the processor itself)? Conceptually,a processor architecture to accom-plish DO loops would take the struc-ture of figure lb, where a DO pointeraddressing a DO stack has beenadded to a processor of simple archi-tecture resembling the 6800 micropro-cessor.

The DO stack would function as aconventional stack, except, unlike aconventional stack that saves the next(return) address for a subroutine, theDO stack saves the next (looping) ad-dress followed by an additional valuen. (See figure 2.) The value n is the in-

teger number of times the loop is tocycle. The loop is initiated with theDO n instruction, but program flowcontinues inline.

The value n could reside in an ac-cumulator or some other processorregister rather than residing in pro-gram memory immediately after theDO op code. Then a reference to alocation or register that contained theaddress of the operand value wouldremove the need for self-modifyingcode if n were to be a variable (e.g.,DO {n) or DO Rn). To show as simplyas possible the operation of the DOinstruction, the general form DO nwill be used here.

The DO loop is bounded by anNXT instruction op code. Upon reach-ing this instruction, the control logic inthe processor uses the DO pointer toreference the location of the value non the DO stack. The value n is thentemporarily pulled and decremented.If the value of n is not 0 after the de-crement, the new n value is pushedback onto the stack, and the next twostack values (D-2 and D-l) are readout as the address to loop back to forfurther iteration. Figure 2 comparesthe conventional stack pointer to thenew DO pointer in more detail.

414 October 1981 © BYTE Publications Inc

Circle 244 on inquiry card.

(la)

ADDRESSBUS

STACK POINTER

INSTRUCTIONREGISTER

PROGRAMCOUNTER

CONTROLDECODER

TEMPORARYREGISTER(S)

INDEXREGISTER(S)

ACCUMULATOR(S)

BUFFERS

<^>

DATA/CONTROLBUS

Figure 1: Block diagram of a typical processor with stack pointer. Figure la is based onthe 6800 microprocessor; in figure lb (see page 416), the DO Pointer has been added.

If the value n is 0 after being decre-mented, however, the DO loop is de-fined as being completed. The DOpointer is adjusted to its preloopvalue (D) and execution continueswith the first instruction after theNXT op code.

DO loops can be nested using theserules. Well-designed DO loops con-figured under the same nesting rulesas FORTRAN or BASIC would not

terminate prematurely. The DOpointer could be in error onlythrough procedures that are com-monly accepted as illegal in high-levellanguages or procedures in assembly-language programming similar to il-legal exits from subroutines and inter-rupts.

A DO loop controlled by a DOpointer would then match high-levellanguage requirements and would re-

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(lb)

STACK POINTER

DO POINTER

INSTRUCTIONREGISTER

CONTROLDECODER

ADDRESSBUS

s\

BUFFERS

PROGRAMCOUNTER

TEMPORARYREGISTER(S)

INDEXREGISTER(S)

ACCUMULATOR(S)

N^7

DATA/CONTROLBUS

Mnemonic

Present Similar Implementation (and processor)

DOn

none(?)

NXT

DBCC (Motorola 68000)LOOPE/LOOPNE (Intel 8086)

ABS N

ABS N (Texas Instruments TMS 9900)

ASC NBIN N

XLAT ASCII TBL (Intel 8086)

SRCH n,SRCH n,

M

- m

SEAF 0, Md (Advanced Micro Devices HEX-29)LOCC n, L, M (DEC VAX 11/780)CPIR (CPDR) (Zilog Z80)SCAZ TXT LINE (Intel 8086)

Table 2: Present implementations of "new" instructions.

416 October 1981 © BYTE Publications Inc

JSR (EXTENDED)

DO #n

BEFORE

AFTER

BEFORE

AFTER

CONVENTIONAL

STACK

MEMORY

■"

S -2

S-l

SP—*-S

S + l

29

S + 2

4A

S-3

S-2

S -1

<(P+3)H>

s

<(P + 3)L>

S + l

29

S+2

4A

DO

STACK

MEMORY

DP-

D-3

D-2

D-l

»D

D + l

35

D+2

17

~~

P-»-D-3

D-2

n

D - 1

<(P + 2)H>

D

<(P+2)L>

D + l

35

D + 2

17

PROGRAMMEMORY

► p

JSR

p +1

AH=SUBR ADDR

P+2

AL= SUBR ADDR

P+3

NEXT INST

_ ^

'

P

JSR

P+l

AH=SUBR ADDR

P+2

AL=SUBR ADDR

P + 3

NEXT INST

PROGRAMMEMORY

PC—*-P

DO

p + l

n

P+2

NEXT INST

v

"~

P

DO

P+l

n

PC-»P + 2

NEXT INST

PC —»-A

FIRST SUBR INST

A=<AH-,AL>

^

Figure 2: Comparison of a Jump to Subroutine instruction with proposed DO instruction. This diagrams the positions of the SP (stackpointer) relative to the PC (program counter) and the DP (DO Pointer) relative to the PC—both before and after the respective in-structions have been executed (based on the architecture of the Motorola 6800 microprocessor).

lieve compiler writers of the burdenof performing these operations withlong strings of assembly-language in-structions. The DO loop would alsobe made available to assembly-lan-guage programmers and microproces-sor-hardware engineers.

What about the processors current-ly competing on the market? In table2, there is a reference to the DBCC in-struction of the 68000 microproces-sor, which performs the function ofthe proposed NXT instruction. Butthe user is left without the benefits ofthe automatic stacking operations ofthe proposed DO Pointer.

Variations

Studies of op-code usage haveshown that the DO loop feature I've

described could be "appended" tocommon op codes, such as ADD,SUB, IN, and OUT, so a commonfunction could have the added fea-tures of automatic DO pointing. Forexample:

DOn

SUB CONSTANT

NXT

would become:

SUBDO n, CONSTANTNXT

This approach, however, involves adeparture from the regularity desiredin modern instruction-set designs.Single instructions with the loop-

and-decrement mode are already avail-able in several forms on the Z80(LDIR and LDDR for moves; CPIRand CPID for the SRCH function;INIR, INDR, OTIR, and OTDR forinput/output; and DJNZe for a func-tion similar to NXT). The Z80 doesthese without benefit of a true DOpointer and without being able tocombine arithmetic instructions andother general functions under onemain DO loop.

It is feasible (and imperative) that ageneral DO architecture be includedin future processor designs. There is ademonstrable need for the DO archi-tecture, and it has been shown howsuch operations can be incorporatedeasily into many of the available ar-chitectures.

October 1981 © BYTE Publications Inc 417

I

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Summary

Modern processor instruction setsare by no means complete, if com-plete is defined as providing for allsimple, regular instructions thatcould be of significant value to pro-grammers and engineers. Instead, anall too common complaint is that afew basic instructions are either non-existent or difficult to find in mostprocessors, and trade-offs in originaldesigns of many processors have leftsome addressing modes incompletelysupported. For example, one popularmicroprocessor implements branches,jumps, and subroutine jumps, butomits the branch to subroutine that isso useful in writing position-indepen-dent code.

It seems that restrictions of semi-conductor die size has often "squeezedout" some useful instructions as aone-time cost savings. The result:programmers endlessly emulate de-sired, but unavailable, instructionswith long sequences of other existinginstructions. This has proved costly.

The magnitude of the programmingtasks to be accomplished in the com-ing years could be reduced consider-ably with more useful assembly-lan-guage instructions. The challenge ofthe 1970s was to design newer andbetter processors. The challenge forthe 1980s is to promote the evolutionof processors with high-level instruc-tion sets to help alleviate the soft-ware-management problem. The DOloop is one example of assembly-lan-guage- and processor architecture-re-lated development that should beconsidered. ■

References

Computer Structures: Readings and Ex-amples. C Gordon Bell and Allen Newell.McGraw-Hill, 1971.

VAX11/780 Software Handbook. DigitalEquipment Corporation, 1977.M6800 Microprocessor ApplicationManual. Motorola. McGraw-Hill Inc, 1975.Build a Microcomputer, Chapter VIII, HEX29. Advanced Micro Devices, 1979.9900 Family System Design and DataBook. Texas Instruments, 1978.MC68000 Microprocessor Users Manual.Motorola, 1979.

418 October 1981 © BYTE Publications Inc

Circle 91 on inquiry card.

Programming Quickies

Apple Pascal Cross-Reference

Robert J Woodhead, Siro-tech Software Products6 Main St, Ogdensburg NY 13669

Debugging a long or complex program can be mademuch easier by using reference listing. A utility programcan easily generate one from the source code, listing theline numbers of all program statements in which eachvariable or named constant is used.

Niklaus Wirth developed an efficient binary-tree-search algorithm for this purpose (discussed in his bookAlgorithms + Data Structures = Programs. EnglewoodCliffs NJ: Prentice-Hall, 1975). The algorithm was used inthe program APPLE3:CROSSREF provided with theApple Pascal system. I found CROSSREF unsatisfactoryin some ways, however, so I took the basic concepts anddeveloped my own version of the cross-reference pro-gram, adding features that make the program bettersuited for use with the Apple Pascal language system.

The new features include:

• ignoring the characters in comments and quoted-stringliterals

• dividing the source-code and cross-reference listingsinto pages with titles

• automatically extending the search into separate disk

files that contain source code routed to the compiler bythe include-file mechanism• top-down recursive design

The result is a more readable output listing for programswritten in Pascal.

My modified version of the Wirth cross-reference-gen-erator program is shown in listing 1, and its own cross-reference table is shown in listing 2.

A disadvantage of the program given here is that thedata tables containing the cross-references are stored inmemory, thus limiting the size of the input programs thatcan be processed. An improved version that I have devel-oped stores the tables on disk, allowing cross-referencingof very large programs. You can obtain both the im-proved version and a spooler program that lets you spec-ify multiple files for printing from my company for $20.A floppy disk containing both source and pseudocodefiles is provided. ■

Interested readers can contact Siro-tech Software Products at (315)393-2640.

Listing 1: Apple Pascal cross-reference program based on a similar utility program provided with the Apple Pascal language system.This version includes several useful additions. Note paging and titling of the listing.

I- C**I-,R- t)

3- PROGRAM CROSSREF;

5 ■■ (, ******t#£&1l#*XX*^^ >

€■■ ■::* t)

?■■ «: CROSS REFERENCE GENERATOR USING BINARY TREE. *>

8= it FROM I.IIRTH,ALG0RITHMS+0ATA STRIJCTURES=PROGRAMS..R£06 *)

9-- (Z *)

10: <t MODIFIED 17-SEP-SO BY ROBERT WOODHEAD FROM APPLE3' *)

11= <* CROSSREF PROGRAM. OPTIMIZED FOR PASCAL TEXTFILE *5

12= <* CROSSREFERENCING, WITH THE FOLLOWING FEATURES. *)

13= «: :*:;,

14= <* 1) LISTING IS PAGED *)

15^ <* £> CONTENTS OF COMMENTS AND QUOTED STRINGS ARE NOT *)

Listing 1 continued on page 421October 1981 © BYTE Publications lnc 419

Circle 142 on inquiry card.

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A compact bi-level desk ideal for an Applecomputer system. This 42" x 31 M>" desk comeswith a shelf to hold two Apple disk drives.Thetop shelf for your TV or monitor and manualscan also have an optional paper slot to accom-odate a printer.

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Get your micro computer off the desk top andinto the micro shelf under our Designer Seriesdesks. Suitable for the North Star, Dynabyte,Vector Graphics, and Altos computers. Thedesks come in a variety of sizes and colors.

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420 October 1981 © BYTE Publications Inc

HIS

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Send your check to: United Negro College Fund, Box B, 500 E.62nd Street, New York, New York 10021. We're not asking for a handout,just a hand.

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A public service of this magazine and The Advertising Council.

Circle 84 on inquiry card.

Programming Quickies.

Listing 1 continued:

16' (,_% INCLUDED IN THE CROSS REFERENCE t

!?• it 3) PROGRAM WILL FIND AND INCLUDE FILES THAT WOULD *

IS' it BE INCLUDED BY THE COMPILER INCLUDE MECHANISM *

19' C* 4) PROGRAM CONSIDERABLY CLEANED UP! *

P.O. <:.% t

a'i

CONST CI =10: >:. * LENGTH OF TOKENS STORED IN LIST

t

l.. r

C2=10J it NUMBERS PER LINE OF XREF LIST

t

£5 :

C3=6j it DIGITS E'ER NUMBER IN XREF LIST

t

PS^

C4=3000O; it MAX LINE NUMBER IN PRINTOUT

t

"i—1 .

c ■■■ ■

LP=57.: C* # OF LINES, PAGE (66-6-3 MARC INS)

t

C "■■ :

TYPE ALPHA=FACKED ARRAY!1..CI ] OF CHAR;

30 :

WOROREF="WORO;

31'

ITEMREF="ITEM;

3£:

WORD=RECORO

33 :

KEY: ALPHA; <* TOKEN

t

34:

FIRST,LAST: ITEMREF; (* LINKEDLIST OF LINE:

5*

35 =

LEFT-RIGHT: IJORDREF; it TREE POINTERSEND;ITEM=PACKED RECORD

*

3 b ;

"7"7 ■

■_' .•■ ■

3R :

LNO' 0. ,C4.' (* LINE NUMBER

*

39:

NEXT: ITEMREF;<* LINK POINTER

*

40:

END;

41'

4£:

VAR ROOT; WORDREF; it ROOT TO TREE OF TOKENS

*

43:

K ; INTEGER; (* LENGTH OF CURRENT TOKEN

*

44:

N ; INTEGER.; it CURRENT LINE NUMBER

*

45'

ID : ALPHA.; (* TOKEN BEING PROCESSED

*

46:

A : ALPHA; it TOKEN BEING BUILT

*

47:

CH : CHAR; it CURRENT TOKEN CHARACTER

*

48:

LI HELEN.. it OF THE CURRENT LINE

*

49:

CHARPOS:INTEGER;

50:

FLEVEL 'INTEGER.; it FILE WE ARE CURRENTLY USING

51:

LINE--STRINGC255 ]i it CURRENT LINE BEING PROCESSED

*

5£:

Fl,

53:

FB,

54:

G : TEXT; it INPUT AND OUTPUT TEXTFILES

*

55:

TITLE;STRING; (% TITLE OF PRINTOUT *

■>

56 :

SOURCE, it INPUT AND OUTPUT FILENAMES *

:>

57:

DEST' STRING! BO!,;

59 :

it PAGER DETERMINES IF A RAGE EJECT IS REQUIRED, AND IF *

;,

60:

it SO, IT DOES IT AND PRINTS THE HEADER *

)

6£ :

PROCEDURE PAGER.;

64:

BEGIN it PAGER f)

64:

EEC

IN

it

PAGER *)

65:

€■€■■■

IF

i N

MOD LP)=0 THEN

67;

BE

JIN

68'

WRITELNC '<',N:5.

1> [',MEMAVAIL:6,

' ]

69 :

70:

IF N>0 THEN

71:

BEGIN

WRITELNC G

73:

WRITELNCG

74:

writelikg

75:

END.;

76 ■■

WRITELNC G);

??■■

URITELNCG,'XREF

LISTING OF FILE '

,

Listing 1 continued on page 422

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Computer Furniture and

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(213) 327-7710

October 1981 © BYTE Publications lnc 421

Circle 260 on inquiry card.

Send for ourFREE Catalog

ADDRESS LABELS

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Shipping is even included,

but you must mention Ad #B9

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This special price is just tointroduce you to our catalogof computer accessories andword processing supplies.We offer you 25-50% off onproducts like 3M-Scotch*brand diskettes, computerpaper, ribbons, printwheels.binders, and alot more.

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Company-Address _City

Programming Quickies.

Listing 1 continued:

80 :

81 =

SOURCE,

' '!< 74-

•9-21-

LENGTHC S

:iijrce::o..

'PAGE '.

o:h div

LP)+1

>'4)i

I...IRITELNC

G

i ;

WRITELNC

G,

i 1 . / ~7~).

TITLE);

-< LENC

TH<TITLE

) DIV 2

I..JRITELN':

G

H

WRITELW

G

■>

30 :91 ■

END;

* IN CASE YOU ARE WONDERING WHY IT'S 74 AND 37 INSTEAD

* OF 80 AND 40 IN THOSE I..JRITELNS, IT'S BECAUSE 80 COL

* PAPER USUALLY WILL HOLD <S6 COLS. THE CHANGES MAKE

* SURE YOU WILL SEE THE PACE NUMBERS.. ETC

*>*>*)

94 = END; U FACER *)

96 = it GETLINE READS A NEW LINE FROM THE INPUT FILE. IF97' (.* IT DETECTS AN END OF FILE.. IT PRINTS OUT THE XREF

99 = PROCEDURE GETLINE.;

100 :

101= O: ENDITALL PACE EJECTS AND STARTS THE XREF LIST.. THEN

103' (* EXITS THE PROGRAM

103'

104' PROCEDURE ENDITALLJ

105'

186= <* PRINTREE RECURSIVELY CALLS ITSELF TO PRINT THE TREE

107' (t OF CROSS REFERENCES

1 08'

103' PROCEDURE PRINTTREE<W= WORDREF),

110'

111' <t PRINTWORD PRINTS A SINGLE CROSS REFERENCE

112'

113' PROCEDURE PRINTWORCK U ' WORD >;

114'

115' VAR

116' L' INTEGER;

117' X' ITEMREF'

*:)

113 =

120'121 ■122'123'124 =125'

123'130'131'132'133'134'135'136'137 =133'133'14S'141 '

SIN <* PRINTWORD #)

PAGER.;

N=Nfl;

WRITECG.. ' '..W.KEY);

X'=W.FIRST;

L'='0;

REPEAT

IF L=C2 THENBEGIN

PAGER;H-=N+l.i

WRITELHCG).;L"=0;

WRITECG,' 'END;

Cl + 1 )

L = =L+l.i

UIRITE'::C..X".LN0'C3);X'=X".NEXT.;

Srare/Zip

•3MC0.

Circle 297 on inquiry card.

Listing 1 continued:

JNTIL X=NIL;

3 44:145 •146: END

* PRINTWOF

ppQTt..; ( ;±; PpTHTTRc'

IF I.

END;

GINPR INTTREEC IT. LEFT').;PRINTWQRDCuT);

pf. ^TTPEF1. ■ '■'' PirMT'

* PRINTTREE *

144:

159^

151:

152:IS-!-154:

153:156:1 57 :

158-

159:

160: BEGIN <* ENDI TALL *)161 :

WHILE CN MOD LP K>0 DOBEGIN

N:=N+1.;UIRITELN(G)END:

PRIHTTREECRUOT);

EXIT(PROGRAM)

; C* END I TALL f.

:* CHARACTER POS PTR:l:* TEMP FILE NAME

162;

163:164:165:166:167:168:168:170:171 :

17E': END

173:

174: of: AHINCLUDE OPENS THE INCLUDE FILE AND READS

175: a: in THE FIRST LINE

176:

177: PROCEDURE AHINCLUDE;

178:

179: VAR

180: SOFHAME,

181: EOFNAME:INTEGER;

182: THAME 'STRING;

184: BEGIN C* AN INCLUDE &>

135:

1 86 : SOFNAME : =POS< ' (*$I '.LI HE H<

187:

188-

189:190:191:138:123:194:195:

13C:

137:133:199:200:201:

202 :

203 :204:205:

286'

THAME—LINE;DELETE*THAME,

EOFNAME:=POS<

SOFNAME >;3' ., THAME ;

IF EOFNAME=0 THEN

EXITC AN INCLUDE); (. * WAS NOT AN IHCLUDI

THAME : =COPY< TNAME, 1, EOFNAME-1 >j

WRITELI-K 'INCLUDE FILE — >',TNAME);

* )

FLEVEL:=2;RESETCF2.. TNAME);

IF IORESULT>0 THENBEGIN

CL0SECF2);

FLEyEL:=FLEVEL--lEND;

Listing 1 continued on page 424

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October 1981 © BYTE Publications Inc 423

Circle 4 on inquiry card.

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Programming Quickies.

Listing 1 continued:

£10

£11£12£13

Oi A

l_ J. "T

£15£16

£17£18£13££@££1

££4

£38

£31

£41-3£41£4££43£44£45£46£4?£48£43£58£51

£54

•;icc

£56

£61

£64

GETLINE.;

END: {% AN INCLUDE *)

BEGIN C* GETLINE *)

IF FLEVEL=£ THENBEGIN

IF EOF(FS) THEN<* MOVE BA(BEGIN

CLOSECFS);FLEVEL'=1ENDENDELSE

IF EOFCF1) THENENDI TALL,

PAGERiN-=N+1;

IF FLEVEL=1 THEN

READLNi FELINE)ELSE

READLN<F£,LINE):

LINE :=C0NCATC LINE, ' ' >.;

LINELEN'=LENGTH<LINE)j

CHARPOS==lsWRITELN<G,N-C3, ' : '..LINE);

IF P0S< '<*$I ',LIHE)>0 THENIF FLEVEL=1 THENAN INCLUDE.;

,;■ ;i; Tj-|rr pr T [.;: ::;t I yuc pr riLE-t'-;

<* CHECK AND HANDLE EOF *

0 FILE 1 *.:

END;

3ETLINE *

(* READCH IS THE FUNNEL THROUGH WHICH THE REST *;(* OF THE PROGRAM GETS CHARACTERS. IT FILTERS *;0* OUT COMMENTS AND QUOTED STRINGS *:

PROCEDURE READCH.;

<* NEXTCHAR ASSIGNS TO CH THE NEXT CHAR IN THE #;<* INPUT STREAM *;

PROCEDURE NEXTCHAR;

BEGIN C* NEXTCHAR #)

WHILE CHARPOS>LINELEN DO C* SKI Pi: BLANKS

GETLINE;

>h=LIHECCHARP0S3i

:harpos^=charpos+i> (* nextchar *>

SPANQUOTE SKIPS CHARACTERS UNTIL IT FINDQUOTE ('> CHARACTER. IT THEN CALLS READCREAD IN A VALID CHARACTER. SINCE READCHCALL SPANQUOTE OR SPANCOMMENT, THE EFFC

TO KEEP RECURSIVELY CALL3IN A COMMENT OR A QUOTE!

T ISUNTIL WE ARE NOT

424 October 1981 © BYTE Publications Inc

Circle 256 on inquiry card.

Listing 1

cor

tinued:

£74 :

( *

■--icr .

(t

PS-- OONT YOU

!' iST

£76 :

c/ .■• ■

PR

DCEDURE SPANQ

JOTE ;

278 ;

£79 :

BE

SIN <t SPAN8U

JTE *

£80 :

£81 i

REPEAT

COC :

M^yT^HAR

£83-

UNTIL CH=i ' '

1 .;

£84 :

£85:

READCH

LOVE RECURSION!

#>

£87: END; <* SPANQUOTE *>

283- ''* SPANCOMMENT DOES A SIMILAR DASTARDLY THING

£90: <t AS SPANQUOTE. ONE COMPLICATION IS THAT HE

£91: (:{; HAVE TO LOOK OUT POR THINGS COMMENTS LIKE'

£9£: CU *)

£93^ (;(: $#)

£94: (****)

£95: ,;•*■ THIS IS DONE BY A WHILE INSIDE A REPEAT

£96:

£97: PROCEDURE SPANCOMMENT;

£98:

£99: BEGIN <* SPANCOMMENT *)

306 :

NEXTCHAR; C* FLUSH THE * OF THE LEADING PAREN*)NEXTCHAR; <* GET THE FIRST CHAR TO LOOK AT *)

WHILE CHO't:1 DO C* FIND AN ASTERIX *D

NEXTCHAR;NEXTCHAR <* GET THE CHARACTER AFTER *)UNTIL CH='V; <* IF A ) WE ARE OK, ELSE IT #)<* MAY BE A * SO REPEAT! *)

30138£3033843053HC307368309

310:311 :31 £:313:314:315:316 :317:313:319:

320 :

321 :

i£4:

READCHEND; i* SPANCOMMENT *BEGIN C* READCH Z)

NEXTCHAR;

(* READ THE CHARACTERC* SKIP IF NEEDED

330:

334:

336

IF CH='''' THEN

SPANQUOTEELSE

IF CH='(' THEN

IF CHARPOS<=LINELEN THEN

IF LINECCHARP0S3='*' THENSPANCOMMENT;

END; U: READCH * )

<* PROCEDURE SEARCH WILL SEARCH FOR THE TOKEN *)Ct: IN ID, AND IF FOUND, INSERT THE LINE* IN ITS *)<* LINKED LIST. OTHERWISE IT WILL CREATE IT *)

PROCEDURE SEARCHCVAR Wl ■■ WORDREF);

VAR

1.1: WORDREF;X- ITEMREF;

BEGIN

Listing 1 continued on page 426

Mil stocks 'em allfor faster delivery.

No hidden charges. Prices include delivery.

Ask about our "QED " discounts.

VISA and MasterCard orders accepted.

MTI

VIDEO TERMINALS Price

VT100 DECscope $ 1635

VT1 32 DECscope 1995

ADM 3A (dumb terminal) 595

ADM 5 {dumb with visual attributes) . 645

ADM 31 (2 page buffer) '

ADM 32 (ergonomic ADM 31) '

ADM 42 (8 page buffer avail.) "

Tl 940 (2 page buffer) 1795

Tl "Insight Series 10" personal term. .. 895

Hazeltine Executive 80 Model 20 1375

Hazeltine Executive 80 Model 30 1715

Hazeitine Esprit 645

1410 (Hazeltine dumb terminal) 825

1420 (dumb terminal) 895

1421 (Consul 580 & ADM 3A comp.).. 850

1500 (dumb terminal) 1045

1510 (buffered) 1145

1520 (buffered, printer port) 1395

1552 (VT52 compatible) 1250

GRAPHICS TERMINALS

VT100 with graphics pkg 3250

ADM 3A with graphics pkg 1875

ADM 3A+ with graphics pkg 1925

300 BAUD TELEPRINTERS

LA34-DA DECwriter IV 995

LA34-AA DECwriter IV 1095

LA36 DECwriter II 1295

Teletype 4310 1095

Teletype 4320 1195

Diablo 630 RO 2295

Diablo 1640 KSR 2775

Diablo 1650 KSR 2835

Tl 743 (portable) 1190

Tl 745 (port/built-in coupler) 1485

Tl 763 (port/bubble memory) 2545

Tl 765 (port/bubble/b.i. coupler) 2595

Tl "Insight Series 10/1" pers. term. ... 895

600 BAUD TELEPRINTERS

Tl 825 RO impact 1450

Tl 825 KSR impact 1570

Tl 825 RO pkg 1625

Tl 825 KSR Pkg 1795

Tl 840 RO impact 1095

Tl 840 KSR impact 1245

1200 BAUD TELEPRINTERS

LA120 RO (forms package) 2095

LA120 AA DECwriter III (forms pkg.) 2295

Tl 783 (portable) 1645

Tl 785 (port/built-in coupler) 2270

Tl 787 (port/internal modem) 2595

Tl 810 RO impact 1455

Tl 810 RO pkg 1G90

Tl 820 KSR impact 2025

Tl 820 RO 1850

Tl 820 KSR pkg 2195

Tl 820 RO pkg 2025

2400 BAU D

Dataproducts M200 12400 baud) 2595

DATAPRODUCTS LINE PRINTERS

B300 1300 LPM band) 5535

B600 1600 LPM band) 6861

B900 (900 LPM band) 10164

BP1500 (1500 LPM band) 16785

2230 (300 LPM drum) 7723

2260 (600 LPM drum) 9614

2290 (9O0 LPM drum) 12655

ACOUSTIC COUPLERS

A/J A242-A (300 baud orig.) 242

A/J 247 (300 laud orig.) 315

A/J 1234 (Vadic compatible) 895

Vadic VA 3413 (300/1200 orig.) 825

Vadic VA 3434 11 200 baud orig.) 845

MODEMS

GDC 1 03A3 (300 baud Bell) 395

GDC 202S/T (1200 baud Bell) 565

GDC212-A (300/1 200 baud Bell) 850

A/J 1256 (Vadic compatible) 825

VA103 (300 baud orig./ans.in phone) 235

VA 3451 (orig./ans. triple modem) .... 885

VA 3455 1 200 baud orig./ans.) 770

CASSETTE STORAGE SYSTEMS

Techtran 816 (store/forward) 1050

Techtran 817 (store/for/speed up) 1295

Techtran 818 (editing) 1795

Techtran 822 (dual) 2295

FLOPPY DISK SYSTEMS

Techtran 950 (store/forward) 1395

Techtran 951 (editing) 1995

■Please call for quote

mti

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October 1981 © BYTE Publications Inc 425

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Programming Quickies.

Listing 1 continued

346

I...I :

=W1

<* ROOT OF BINARY < SUE )TREE

:*:)

341

34£

IF

W=l

JIL THEN

34.3

BEl

5IN «: IF (SUB)TREE IS NIL, CREATE

t)

344

NEWC LJ) i (.% WORD RECORD

;i; )

345

HEW<X).i<* AND LINE* RECORD

*)

345

WITH IT DO

347

BEGIN

34 ft

KEY—ID; C* STUFF IN THE DATA

;i; )

349

LEFT—NIL;

35m

RIGHT—NIL;

351

FIRST—X;

35E'

LAST—X;

-j"c;-7

END;

354

X".LN0—N;

X".NEXT—NIL;

357

END

35 ft

EL

3E

Of HON EMPTY TREE

*3

IF

IDar.KEY THEN

360

SEARC+KW.LEFT) (* RECURSIVE SEARCH!

i' ''<

361

EL

3E

36£

IF ID>I.,.|- .KEY THEN

3G3

SEARCH<W".RIGHT) (t AND AGAIN

#)

364

ELSE

3t<^

BEGIN <* FOUND IT.. ADD DATA

*)

366

HEWCX);

367

X".LN0—N;

36ft

X". NEXT—NIL;

369

U".LAST".NEXT:=X;

370

kT.LAST —x;

371

END;

374

530

481

-1 02

403

404405406

END; (* SEARCH *:)

BEGIN <* MAIN *

R00T==NIL; C* EMPTY TREE TO STARTFLEVEL==1; C* ON FIRST FILE AT THE STARTN'«0J

*)*)

URITELHC CHRC IE' ), 'MODIFIED XREF PROGRAM - 17-SEP-S0 BY RJW'X

URITELN;

WRITELNC'ENTER A TITLE FOR YOUR XREF BELOW'');

I...IRITELN;

READLHC TITLE).;

WRITELH;

REPEAT

MR I TEC 'SOURCE FILE ? >' );

READLHCSOURCE);

IF P0S< ' . ', SOURCE )=8 THEN SOURCE— CONCATC SOURCE, ' .TEXT' );

RESETCF1,SOURCE)UNTIL IORESULT=0;

REPEAT

I..JRITEC 'DEST FILE ? >' );

READLHC DEST);

REWRITECG,DEST)UNTIL IORESULT=0;

WRITELN;

URITELHCURITELHC

GETLINE;

.IHE#> [MEMORY]' );

INITIALIZE THE SYSTEM

*)

426 October 1981 © BYTE Publications Inc

Listing 1 continued:

4?.?- REPEAT C* FOREVER MORE *)

403:

403 : REPEAT C* FIND 1ST CHAR IN A TOKEN *)

416 ^ READCH.;

411 ■ UNTIL CH IN [ ' A ' . . ' Z ' , ' a ' . - ' z ' , ' 0 ' . . ' 9 ' ].;

412 =

413- K = =0i it ZERO LENGTH OF TOKEN AND TOKEN! *)

414'

415; FI LLCHAR< A, ST ZEOFC A >, ' ' ) >

41S'

417: REPEAT « FILL UP TOKEN *>

413:

415: IF K<C1 THEN

4£@: BEGIN <* ADD CHAR TO TOKEN *)

421' K==K+1;

422; ACK]:=CH;

423' END;

4£4:

425 = READCH; C* GET NEXT CHAR IN TOKEN *>

426:

427 : UNTIL NOTC CH IN C ' A ' . . ' Z ' , ' a ' . . ' z ' , ' 0 ' . . ' 9 ' ]).;

423:

423: ID'=A.i C* INSERT TOKEN INTO TREE *)

430: SEARCH( ROOT).;

431'

432: UNTIL FALSE C* WILL HIT EOF IN GETLINE *>

433;

434: END.

Listing 2: Table of the cross-reference generator as produced by the program in listing 1.

XREF OF XREF

@ 38 6b 79 125 134 162 133 803 £41 388

~'f1

185

399

413

188

138

830

1 83 81 188 138 135 138 164 183 136 ISi

10 83 84

18 388

c

86

81

855

30080

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4

800

fc,

cl-j

74

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£ 3

BEGIN,

f si

4«tj df,

1 94

804 81"

130 148 151 160 163 18*petes p-?q ?Q<a 314 33k 7.4Z

Listing 2 continued on page 428October 1981 © BYTE Publications Inc 427

Programming Quickies.

Listing 2 continued:

347

365

376

4£8

Cl

cl>

£9

135

413

C£

£4

1£9

C3

L_-J

139

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47

£63

C C1 •-'

304

307

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CHAR

47

CHARPOS

43

Uv'U

£60

263

£64

£64

CHR

■l"ZlC

CLOSE

£05

£19

COHCAT

£35

391

CONST

lL-J'

COPY

136

CpnsspEF

"7

DELETE

189

DEST

ur~)

397

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DIV

81

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162

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304

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C C -J'

c •!> c

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361

364

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36

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£07

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£45

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371

373

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164

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43£

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415

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34

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351

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135

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99

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411

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43

44

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116

181

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399

ITEM

31

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34

39

117

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K

43

413

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116

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1£3

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34

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428 October 1981 © BYTE Publications Inc

LP

MEMAVAIl

MOD

N 122 122 132

NEW

NEXT

NEXTCHAR £56 282 381 30£ 3K

NIL 142 150 342 343 356

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66

162

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154

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170

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£85

310

418

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386

390

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TO

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1 O"?

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332

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RIGHT

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350

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42

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438

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180

186

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78

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241

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318

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55

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182

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387

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193 £03 £15 £17 ££4 £30

196 198 281411 42? 432152 153 154

October 1981 © BYTE Publications Inc 429

Multiple Regressionfor the TRS-80

Thomas William Madron

Manager, Academic Computing Services

North Texas State University

POB 13495

Denton TX 76203

Within the context of a largenumber of scientific and technologi-cal problems it is necessary to be ableto predict a score or value of avariable (Y) from one or more predic-tors (Xs). One method commonlyused to accomplish this feat is multi-ple linear regression.

This article deals primarily withconverting the mathematics of linearregression into a general-purposeBASIC computer program; therefore,only a very brief discussion of themathematics is presented. Readersshould consult the references for thisarticle for a detailed treatment ofmultiple linear regression.

The fundamental equation forlinear regression using a single predic-tor is:

Y = a + bx

where V (Y prime) constitutes thepredicted value(s) of the dependentvariable; X is the predictor or in-dependent variable; a the interceptconstant; and b the regression coeffi-cient. Suffice it to say, at this point,that multiple regression is an exten-sion of simple linear regression:

Y = a + bjX, + b2X2 + • ■ •+ b„X„

where X,...X„ constitutes a set ofpredictors and bi...b„ a set of regres-sion coefficients.

The primary problem in computinga regression lies in determining valuesfor a and b. One formula that may beused to calculate a is:

a - Y - bX

where Y (Y-bar) and X (X-bar) arethe mean values for Y and X. As withthe prediction formula, there is astraightforward extension to themultivariate case:

a - Y - b.X,- b„X„

b2X2 —

One of the primary problems, then, isto solve for the fas so that we maycalculate the equation.

For one or two independentvariables, the calculations for theregression coefficients are straightfor-ward, but with more than two in-dependent variables it is useful to usea computer. It turns out that to ob-tain the coefficients, we need to solvea set of simultaneous equations. Theeasiest way to do the arithmetic iswith matrix algebra.

In order to obtain all the coeffi-cients we need, we can use the follow-ing formula (boldface letters denotematrices):

B - RR-' X RY

where B is a vector (in BASIC, a one-dimensional array), RR"1 is the in-verse of the matrix (in BASIC, a two-dimensional array) of correlationsbetween all of the independentvariables taken two at a time; and RYis a vector of correlation coefficientsof each independent variable with thedependent variable. (A correlationcoefficient is a measure of the extentto which two variables vary togetherand, in the two-variable case, is iden-tical to the "standardized" regressioncoefficient b* [fo-star].) The vector Bhas as its elements these coefficients,or fa*s (b-stars). The b*s can be

turned into bs through the use of thefollowing formula:

bj = b*j (sy/Sj)

where sy is the standard deviation ofthe dependent variable and s, is thestandard deviation of each ;th in-dependent variable. This article doesnot propose to explain matrixalgebra, so suffice it to say that thecomputations for inverting matricescan be found in the book by Kerlingerand Pedhazur (reference 3) and in thearticles by Adler (references 1 and 2).In interpreting the results of regres-sion, several additional statistics areuseful. The first of these is the coeffi-cient of multiple correlation, which issimply the correlation between theobserved and predicted Y values(usually designated by the capital let-ter R). The proportion of variance inthe dependent variable explained bythe set of independent variables isgiven by the square of R. Thesignificance of R2 can be calculatedusing an F-test. It turns out that oncewe have accomplished the matrixarithmetic described above, R1 can beeasily calculated:

R2 = fcVv, + b*

+

+ faVv,

and R = ^JR2. The F-test is also astraightforward calculation:

F =

R'/k

(1 - R2)/(N - k - 1)

where k is the number of independentvariables and N is the number ofobservations. F can be tested for theprobability of occurrence by con-

430 October 1981 © BYTE Publications Inc

suiting a table of F values, or by com-putation as in the program described.Now let's turn the arithmetic into auseful BASIC program.

Program Description

When doing statistical program-ming it is often desirable to produce aprogram that has general applicabili-ty to a wide range of data. Indeed, forlarge computers, a number of exten-sive general-purpose statisticalpackages are available. Alas, such isnot the case for microcomputers. But,

the programs provided will run easilyon a 16 K-byte Radio Shack TRS-80Model I Level II computer. Except forthe routines used to format the outputfor the TRS-80 video monitor, nounusual BASIC keywords are used.Later in this article we show how theprogram might be simplified if BASICmatrix functions were available (theyare not for standard TRS-80 BASIC).Many regression programs com-bine the routines to generate correla-tion matrices with the regressioncalculations. Because there are a

number of valuable uses for a "stand-alone" correlation program, I haveprovided two separate programs;data for the second is transferred byan output file from the first. The pro-gram in listing 1 generates a correla-tion matrix from keyboard or tape in-put. On option, the matrix can besaved on tape. The program in listing2 calculates regression. It would beeasy to substitute disk I/O (in-put/output) for tape I/O. Both pro-grams consist of a main calling pro-

Text continued on page 445

Listing Is The correlation-matrix program (la) and a test run (lb). Written in BASIC for the Radio Shack TRS-80 Model I Level II,this program provides a "stand-alone" correlation matrix that may be saved on cassette tape.

10 00 ' CORRELATION MATRIX PROGRAM

1.010 CLEAR % DEF!I NT I--N

1020 ' IF THE ZEROTH ELEMENT OF THE ARRAYS ARE USED, THEN

L030 ' IB MUST -■ ZERO, ELSE IB=1 . ND=THE MAXIMUM DIMENSION

L 0 4

LOU1 0 61071 0 8

) ' F L3 R EACH ARRAY (MAX V A RIA B I... E S ) ,

] ib=o:nd»15

0 DIM RCND,ND>,A<ND>,S(ND)

0 CLSJPRINT "CORRELATION MATRIX PROGRAM'

) PRINT "BY THOMAS MM* MADRON"

1090 PRINT "2132 SAVANNAH TRAIL"

Listing la continued on page 432

SAVE $$

^cippkzcomputer

16K APPLE II 1049.00

32K APPLE II 1074.00

48K APPLE II 1099.00

DISKW/CONTROLLER 499.00

DISK ONLY 445.00

APPLESOFT CARD 139.00

INTEGER CARD 139.00

PASCAL SYSTEM 399.00

SILENTYPE PRINTER 349.00

HAYES MICROMODEM 295.00

Z-80 SOFTCARD 295.00

VIDEX80COL BRD. 295.00

16K RAM BOARD 169.00

RAM MEMORY

FOR TRS-80, APPLE II

16KSET4116'S(200NS) 24.95

DISCOUNT PRICES

ATARP

40016K 349.00

80016K 759.00

410 Recorder 64.00

815 Disk 1199.00

810 Disk 489.00

822 Printer 359.00

825 Printer 779.00

830 Modem 159.00850 Interface Module 179.00

CX853 RAM 85.00

CX70 Light Pen 64.00

CX30 Paddle 18.00

CX40 Joystick 18.00

VERBATIM DISKETTES

Box of 10 51/i" 29.50

Box of 10 8" 39.50

North Star Computers

HR2-2D-32K 2795.00

HR2-20-48K 2956.00

HR2-2D-64K 3145.00

HR2-2Q-32K 2975.00

HR2-2Q-48K 3165.00

HR2-2Q-64K 3360.00

HRAM32K 469.00

HRAM48K 662.00

HRAM64K 849.00

HDS-18 HARD DISK 4025.00

MDS-DRV-D 495.00

MDS-DRV-Q 665.00

ADC-1-D 740.00

ADC-2-D 995.00

ADC-1-Q 795.00

ADC-2-Q 1285.00

SAVE $$

PRINTERS

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EPSON MX-80 FT 599.00

GRAFTRAX 90.00

INTERFACE (APPLE) 75.00

CABLE 22.50

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CENTRONICS 737-3 855.00

IDS445G 815.00

IDS460G 1195.00

IDS560G 1450.00

NEC 5510 W/TRACTORS2650.00

NEC 5520 KSR W/TRAC. 2995.00

QUME 5/45 SPRINTFORMS TRACTOR

2675.00195.00

STARWRITER W/TRAC. 1695.00STARWRITER W/O

TRACTOR 1500.00

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Circle 154 on inquiry card.

October 1981 © BYTE Publications Inc 431

> A STRING VARIABLE <NV*)40 0 0 tU R = N : N C » N ? G 0 8 U B 3 0 0 0

Listing la continued:

110 0 PRINT "DENTON* TX 76201"J PRINT

1110 INPUT "ENTER TOTAL NUMBER OF VARIABLES TO BE CORRELATED"tNU

112 0 IF NV>ND THEN PRINT "*** TOO MANY VARIABLES xxcx" JGOTO 1110

1130 ' NV MUST BE PASSED TO CORE A!

114 0 N V $ ■■■■■■■■ S T R* < N V >■ t N =: N V - ( 1 -113 > J G O 3 UI

1150 CLS11NPUT ''DO YOU WANT THE C0RRELATION MATRIX REPRINTED"J Y$

116 0 IF L E F T $ ( Y » > 1) -=" Y " T H E N O O S U B 3 0 0 0

117 0 CLSJEND

3 0 0 0 '' SUBROUTINE TO PRINT A MATRIX

3010 ' NR-NUMBER OF ROWS, NC-NUMBER OF COLUMNS, IF

3020 ' IB«0 THEN NR--NR--1 AND NONC-1 . IB*STARTING

3030 ' POINT FOR ARRAYS,

3040 FOR I~IB TO NR STEP 10JIA*I+9*IF IA>~NR THEN IA-NR

305 0 FOR J-IB TO NO STEP

J A ■ J + 8 JIF J A > ~ N C T l-l E N J A ~ N C

3 0 6 0 GLSIPRINT "CORRELATION MATRIX"IPRINT TL#

30 7 0 F1*""VAR t"JG1$«'' ###t";F2 $■'' #111"!G2 *«'' ##,##''

3 03 0 PRINT F1*J

3 0 9 0 F 0 R L ^ J T 0 J A 5 P RIN T U SIN G G1 $ J L + 1? I N E X T I... S P RIN T

310 0 FOR L»I TO IA

311 0 P RIN T U SIN G F 2 * 11... +:!. | t F O R M » J T Q J A

312 0 P RIN T U SIN G G2 $ J R (I..., M ) > J N E X T M $ P RIN T J N E X T I...

313 0 PRINT © 96 0,"TYPE 'C TO CONTINUE"53140 Y*.»INKEY$:iF Y'I>-"C" THEN 315 0 ELSE 31403150 NEXT J: NEXT I

316 0 RETURN

40 0 0 ' COMPUTE MEANS, STOMAS, CORRELATIONS

4 010 ' N=»NUMBER OF VARIABLES, N«N-i IF IB (STARTING

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troller. Auto Dials, Auto Answers, Auto with a powerful operating system. Supports complete with a powerful operating system.

Modes (originate/answer), "Direct Con- 25 easy to use keyboard commands and Supports Auto Dial, Auto Answer, 27 easy

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i

w

% % % AM232

^MICBONETI

• • •

■ ryiiCRDNETB

MICROMATEELECTRONICS, INC.

2094 Front Street • East Meadow, New York 11554 • Telephone 516.794.1072

All "Direct Connect" modems are FCC certified. *Registered trademark of Apple Computer, Inc.

432 October 1981 © BYTE Publications Inc

Circle 235 on inquiry card.

Listing la continued:

4020 ' ELEMENT IN ARRAYS~0* ELSE N=N*

4030 GO SUB -'1:1.2 0

4040 GOSUE 4210

4050 T«NStFOR I»IB TO NtA(I)«A(I)/T

4060 S<I>=SQR(R<I,I>/T--A<I>C2> J NEXT I

4 0 7 0 F0R I~IB T0 N I F0R J■ I TO N JIF S CI) *S ( J ) - 0 • 0 TI-IEN 4 0 9 0

4 0 S 0 R ( J ,-I) ~ ( R (I, J ) /T-A (I) 3KA < J) ) /<S< I) »S < J) )

4 0 9 0 R(ItJ)»R<JtI)J NEXT JJR(I,I>»1.0 J NEXT I

41.00 IF Y3$~"Y*' THEN GOSUB 4480

4110 RETURN

412 0 ' SETUP PARAMETERS FOR CORE

413 0 C L S 11N P U T " E N T E R ANA I... Y SIS N A M E " J T I... *4140 INPUT "ARE THE DATA ERGM TAPE"JY1$

41 SO INPUT "DO YOU WISH TO SAVE THE DATA ON TAPE"JY2*4160 INPUT "DO YOU WISH TO SAVE THE MATRIX"JY3$

417 0 Y1 * ■■■: I... E F T $ ( Y1 * , 1 ) I Y 2 * - L E F T * ( Y 2 $ >!) i Y 3 $ « L E F T * < Y 3 $ , 15

4180 IF Y1$+Y2*<>"YY" THEN RETURN

419 0 PRINT"5K*>xERROR>K)K)KYOU CANNOT BOTH READ AND SAVE DATA TAPE"

42 0 0 PRIN T '' RUN IS TER MINA TED"iE ND4210 ■' INPUT/OUTPUT SUBROUTINE POP CORE

422 0 CLSJNS=0JIF Y1$<>"Y" THEN 423 0 ELSE 4240

423 0 IF Y2*<>"Y" THEN 429 0

424 0 PRINT "PLACE DATA TAPE IN RECORDER"4250 PRINT B 96 0,"TYPE 'C' TO CONTINUE'' I4260 Y*«INKEY* J IF Y*~"C" THEN 4270 ELSE 4260127 0 IF Y:U""Y" THEN 4280 ELSE 4290

42 8 0 C L S J P RI NT " D ATA A R E 13 EI NO EN T E R E D F R O M T AI"1 E " ! G O T O 4 31 0

Listing la continued on page 434

NEW PRODUCTS!

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TELEVIDEO SYSTEM I

The Televideo System I is a CP/M1" based single-user computer system. State-of-the-art design andsingle board construction accounts for Televideo'sreliability and exceptional price performance.Cobal. Basic, PL/1 and Fortran are just a few of thehigh level languages available. As your needs growso can your Televideo computer system. TheSystem I can be a satellite computer of a largernetwork of user stations using the multi-processormulti-tasking System II or System III. System Iincludes TS-81 computer, Televideo 910 terminal(950 terminal available at additional cost) andCP/M* 2.2. Nation wide on-site service is availablethrough General Electric service company.

System I specifications: Z80A, 64K Ram, 4K diag-nostic Eprom, two 5" 360K drives, serial and parallelport.

NORTHSTAR ADVANTAGECOMPUTER

The Norths tar Advantage Computer is an integrated

package including full graphics capability. Linecharts, bar graphs, pie charts and 3 dimensionaldisplays are all possible as part of Northstar'soptional graphics/DOS operating system or CP/M'graphics package. All Northstar applications soft-ware is available for the Advantage Computer. Slotsfor 6 additional expansion cards are included.

Specifications: 280A CPU. 64K Ram. Green screen12" monitor, 240 x 640 pixel graphics resolution,

sculptured typewriter-like keyboard, two 5" 360KCP/M"1 is a licensed product supplied by Digital drives.

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See these products and a full line of peripheral equipment in our showroom.

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Zenith Data Systems with world famous quality andreliability are now available from A.E.I. The Z89 andZ90 are standalone micro computers with a onepiece design that simplifies installation and opera-tion. With the board line of PeachTree accountingsoftware and Micro-Pro word processing softwarethe Zenith computers are the ideal small businesssystems. Heathkit/Zenith educational courses areavailable making the Zenith computer an excellentchoice for the first time buyer.

Zenith specifications:

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Z90—64K ram standard. Z80 cpu. 2 serial ports,built in 12" terminal, one 5" 200K drive, expandable.

- .

Circle 38 on inquiry card.

October 1981 © BYTE Publications Inc 433

Listing la continued:

129Q CLSiPRINT "ENTER DATA FOR EACH VARIABLE"

■<K:H)0 PRINT "TYPE 'END' WHEN DATA ENTRY COMPLETED"

4310 IF Y1**"Y" THEN INPUT #~l,NVi

4320 IF Y2$~"Y" THEN PRINT #--I,NV*

4 3 3 0 N V » U A I... ( N V $ ) 5 F 0 R I«IB TO N I A (I) " 0 . 0

434 0 F 0 R J ■■■■■■■ IB T 0 N S R (I, J ) «• 0 * 0 t N E XT' J ! N E X T I

435 0 FOR I*IB TO N

436 0 IF Y1$<>"Y" THEN PRINT "OBS,lJNS+lJ,,VAR,lJI+iJ

437 0 IF Y1*«"Y" THEN INPUT #•--:!.,S$ ELSE INPUT S$

4 3 B 0 IF B $ ■■■■■■'' E N D " T H E N 446 0 E I... S E S < I) ™ V A I... ( S $ ) i N E XT I

439 0 IF Y2$<>"Y" THEN 4420

44 0 0 F O R I«IB T 0 N I S $ ■ 3 T R * (S (I >)4410 PRINT #~1,8$J NEXT I

442 0 FOR I-IB TO MtA<I)*A.<I)+8(I>

4430 FOR J = I TO NV~UR(I*J)=R(I,J)+S(I)xa(J)iNEXT J J NEXT I

444 0 NS="NS+1

4450 GOTO 4350

4460 IF Y2**"Y" THEN PRINT #•■-:!., "END"

447 0 RETURN

4480 ' MATRIX OUTPUT SUBROUTINE

449 0 C M D " T " 1C I... S SPRINT " P R E P A R E M A T RIX T A P E AND R E C O R D E R "

45 0 0 P R1N T Q 9 6 0 > " T Y P E ' C!' T 0 C O N TIN U E'' \45:1.0 Y*=INKEY*JIF Y**"C" THEN 452 0 ELSE 4510

452 0 P RIN T # --:!. , T I... % % ? RIN T # •-1, NV, N S

453 0 F O R I ■■■■■■■ IB T 0 N t P RIN T # ■••■ 11A < I) , S < I) I N E X T I

454 0 FOR I«IB TO N; FOR J "-"I TO NJIF I«J THEN 4560

455 0 PRINT *-l,R(X*J)

WE DISCOUNT PRICES - NOT SERVICE

tipple computer

* Sales and ServiceAPPLE II PLUS 48K

$1,099

APPLE II PLUS 16K $1,025

HARDWARE

DISK II DRIVE & INTERFACE 499

DISK II SECOND DRIVE 439

BASF 5V«" DISKETTES (10) 25

LANGUAGE SYSTEM W/PASCAL 379

INTEGER BASIC FIRMWARE CARD 149

APPLESOFT II FIRMWARE CARD 149

CENTRONICS PRINTER INTERFACECARD .179HIGH-SPEED SERIAL INTERFACE CARD .... 145

GRAPHICS TABLET 649

APPLE IEEE-488 INTERFACE CARD 339

M&RSUP-R-MODRF MODULATOR 25

MICROSOFT Z-80 SOFTCARD SYSTEM 299

MICROSOFT 16K RAM CARD 169

VIDEX 80 COLUMN BOARD 295

HAYES MICROMODEM II 299

AMDEX 13" COLOR MONITOR 429

NEC 12" GREEN MONITOR 255

SILENTYPE PRINTER W/INTERFACE 350

EPSON MX-100 829

QUME SPRINT 5/45 PRINTER 2499

SOFTWARE

APPLE DOS TOOLKIT 65

APPLE PLOT 60

TAX PLANNER 99

APPLE FORTRAN 159

APPLE PILOT 119

APPLEWRITER 65

DOW JONES PORTFOLIO EVALUATOR 45

DOW JONES NEWS & QUOTES REPORTER . 85

THE CONTROLLER 495

VISICALC(16SECTOR) 159

VISIPLOT 149

VISITREND/VISIPLOT 215

DESKTOP PLAN II 159

BPI BUSINESS SOFTWARE (EACH) 335

SUPER TEXT II 125

PROGRAMMA APPLE PIE 110

EASYWRITER (80 COLUMNS) 219

D.B. MASTER 180

WORDSTAR 299

MICROSOFT FORTRAN 149

A

ATARI-

ATARI 800 16K

$749

ATARI 4OO06K) 350

410 PROGRAM RECORDER 69

810 DISK DRIVE 439

815 DUAL DISK DRIVE 1199

16K RAM MEMORY MODULE 89

MICROTEK 32K RAM 179

850 INTERFACE MODULE 159

830 ACOUSTIC MODEM 159

825 PRINTER (CENTRONIC 737) 699

JOYSTICK PAIR 18

LIGHT PEN 65

ATARI VISICALC 149

BASIC LANGUAGE 45

ASSEMBLER EDITOR 45

MUSIC COMPOSER 45

STAR RAIDER 39

COMPUTER CHESS 30

BASKETBALL 30

TELELINK 20

DATASOFT TEXT WIZARD 79

computer age. inc.

Authorized Apple Dealer & Service Center

4688 CONVOY STREET, SAN DIEGO, CA 92111

(714) 565-4062 (800) 854-1941

TO ORDER: Please send cashier's check, money order or personal check(allow 10 business days lo clear). VISA and Master Card credit card serviceadd 3%. American Express credit card service add 5%. Shipping, handlingand insurance in U.S. add 3% (minimum $4). California residents add 6%sales tax. Foreign orders add 10% for shipping. Equipment is subject toprice change and availability. All equipment carries factory warranty. Storeprices differ from mail order prices. TELEX: 697120 DATAMAX-SDG

CALL OR WRITE FOR A COMPLETE PRICE LIST

434 October 1981 © BYTE Publications Inc

Circle 80 on inquiry card.

Listing la continued:

4560 NEXT J{NEXT I157 0 CMD"R"{RETURN

(lb)

RUN

CORRELATION MATRIX PROGRAMBY THOMAS WM. MADRON

2132 SAVANNAH TRAILDENTON, TX 762 0:!.

ENTER TOTAL NUMBER OF MARIAB

ENTER ANALYSIS NAME? TEST DAARE THE DATA PROM TAPE? NDO YOU WISH TO SAVE THE DATADO YOU WISH TO SAVE THE MATEPLACI DATA 7 API .IN Ri: t'DRDl PTYPE 'C TO CONTINUEENTER DATYPE "END" WHEN DATA ENTRY COBS 1 VAR 1 ? 19OPS 1 VAR 2 ? 23OPS 1 VAR 3 ? IS2OPS 2 VAR 1 ? 24OPS 2 VAR 2 ? 28OPS 2 VAR 3 ? 212OPS 3 VAR :l. ? 21OBS 3 VAR 2 ? 29OBS 3 VAR 3 ? ISO

,ES TO BE CORREL

:d?

ON

TAPE?

IX?

Y

TA 1

rOR EA

OMPI

..ETED

CH VARIABLE

Listing lb continued on page 436

74S00

COMPONENTS CONT'D

SN7482NSN7492NSN7493NSN7495HSN7496HSH74122NSN74136NSN74141NSN74151NSN74153NSN741&4NSN74155*SN741S7NSN74160NSN74161NSN74163NSN74164NSN74165NSN74174NSN74175NSN74180NSN74181NSN74303N

27

E PROMS

sv 450ns 4.75ea

TMS27* Ek?cipa

27oe twoea

450ns 2-/bea

2732 1 UBOea

4116 3O0NS 2 0Oea8to« 12.002O0NS 23S.W B for | 5J"jO

2114L 30ONS 295 ea 4 for 2 7Sea2O0KS 3 50*a 4 lo. 3 OOtw

2111 450NS 2 5Oea10lo. 2 00m

74LS00

74LS15874LSHH74LS16274L.SW374LSW474LS16574LSW974 LSI7074 LSI7474 LSI 7574 LSI0074 L.S10174 LS19674LS10774 LS22174LS24074LS24174 LS24374 LS24474 LS24574 LS2S174LS2&374LS2S774 LS25974LS20074 LS27374 LS27974LS29074LS29374LS30574LS36774LS37374LS37474LS37774LSO6074LS670

CPUs■ Z 80

, 2 BOA CTC

Z BOA CPUj Z 80 0O2 16 64K

; 808SA

2901A

MC6800

MISC2102

450NS 95

BO 38NE555AY5 1013AI48614898T26ST2882128216IS410SCRIT410TRIAC7905790679157918780578067B087812

M0330A1PMC1350PMC1358PLM380LM565NLM741WC1458PLM720LM386

7 9510 5010 501290013 507 509 50

1103AUP0765'loppy diskcontrol l«ULN2001TMS440OMC4008PMH0O26D362403O0103OO2

as

14

W/1 40

16

10/ 1 60

1 IS

18

10/ 1 90

1 so

20

10/2 60

1 20

22

10/2 80

<w

24

10/2 80

2B

10/3 SO

55

40

10/4 75

1981

I.C. MASTER* 59.95

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UPD 765C: Floppy Dia* ControINX

2732A: RIWsec EPMM

15.50AY5-1013A:30«B»«I DART 'JX

REAL-TIME CLOCKCALENDAR (MSM 5832)

O«0WIm Mono Matal O.I. CMOS I C

Fwt.'ti

Tima. Month. Data. Vaar, I

DavotWaak

Bua Onantad

1 Bit Data So.

4 Bit Aodraaa

R'wHom Salac •

Inlar Signat

32 ToBKhj ital Control *3-85

Sv Pow Sup

Low Poarat Diaaipation

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XTAL

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OR

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outrtl.nloiconf-rollatd DOwtH tourc*

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ocsc.

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POWER

SUPPLYMODEL«CP198

input -ttO/125voutput -5vdc

ai 6amps

TRS8016K Add-On

Instruct ions*

Dip Switches

S25 95

GLOBAL

Logic Probes

LP_l: 140.00

Pul»» WldtlSOn—c Urnr.lM to On....

lp-3: «6aoo

PulM WH3I

LPK-1:

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to buy MmpulM widthWn«c

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MICROSOFT

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737-1

'950°°753-1'2.995°°

BASE II. inc

800B

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Circle 101 on inquiry card.

October 1981 © BYTE Publications lnc 435

Listing lb continued:

DBS

•'"{

VAR 1 ? 28

OES

't

VAR 2 ? 3 0

DBS

*\

VAR 3 ? 225

ORS

5

VAR :l. ? 28

0B8

i::j

VAR 2 ? 28

DBS

5

VAR 3 ? 19?

OBS

6

VAR 1 ? 3 0

cms

6

VAR 2 ? 26

DBS

6

VAR 3 ? 207

DBS

7

VAR :l. ? 3 0

OBS

7

VAR 2 ? 26

OBS

7

VAR 3 ? 2 0 0

OBS

8

VAR 1 ? 26

OBS

8

VAR 2 ? 25

OBS

8

VAR 3 ? 212

OBS

Q

VAR 1 ? i<i

OBS

9

VAR 2 ? 2?

OBS

9

VAR 3 ? 2 06

OBS

0 VAR 1 ? 3 0

OBS

0 VAR 2 ? 28

OBS

0 VAR 3 ? 22-t

DBS

1 VAR 1 ? 21

OBS

1 VAR 2 ? 23

OBS

1 VAR 3 ? 210

OBS

2 VAR 1 ? 3 0

OBS

2 VAR 2 ? 27

OBS

2 VAR 3 ? 212

OBS

3 VAR 1 ? 28

OBS

3 VAR 2 ? 25

OBS

3 VAR 3 ? 206

OBS

<t VAR 1 ? 3 0

OBS

q VAR 2 ? 27

OBS

"\ VAR 3 ? 216

OBS

5 VAR 1 ? 3 0

OBS

5 VAR 2 ? 2?

OBS

•1

5 VAR 3 ? 212

OBS

f> VAR 1 ? 3 0

OBS

', VAR 2 ? 28

OBS

':■ VAR 3 ? 208

OBS

7 VAR 1 ? END

F'REF

''A

"<E MATRIX TAPE

AND

RECORDER

TYPI

r

■'C-' TO CONTINUI

;:cori

DELATION M

ATRIX

TES'

"

!)ATA

VAR3

1 21 , 0 0 ••- 0 * 0 1 0- 0 , 0 1 1 , 0 0 0

■ *\7>37

>>

CU/I7 0,37 1

, 0 0

TYPE 'C TO CONTINUEDO YOU WANT THE CORRELATION MATRIX REPRINTED? Y

CORRELATION MATRIX

TEST DATA

VAR? 1 2 3

J. 1,0 0 -0,01 ()♦'■! 7

2 -0,01 1,00 0,37

0,

o,s;

1,00

TYPE 'C TO CONTINUEREAD^

436 October 1981 © BYTE Publications Inc

Circle 1 on inquiry card.

APPLE HEADQUARTERS

^cippkz

Now! Write a letterand print immidiately!

' Apple II w/48K.1 Disc w/cont.

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• Epson Interface.

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j-BUSINESSMAN'S SPECIAL-\

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• Sanyo 9" B&W Monitor

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APPLE II ACCESSORIES

DC HAYES MICRO MODEM II 5309

VIDEX 80 COLUMN VIDEO TERMINAL !290

VYDEX KEYBOARD ENHANCER s112

VISICALC, 3.3 s159

SUP'R'MOD s33

Z80 SOFT CARD s298

THE SOURCE s99

WORD STAR by MICRO PRO 3.0 5269

APPLE SILENTTYPE PRINTER s339

APPLE CLOCK/CALENDAR s249

BPI GENERAL LEDGER s320

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Items on sate lor limited lime only, and are subject to limited availability Not responsible for typographical errors This ad supersedes all other adsprior to Oct. '81. All orders subject to verification and acceptance. Minimum shipping and handling $4.95-

Listing 2: The regression calculating program (2a) and a test run (2b) written for the TRS-80 Model I Level II.

(2a)

:i. Q 0 0 " M U i... TIP L E R E G R E S 31Q N P R 0 G R A M

10 10 CLEAR J DEFT NT I-N

1020 ' IF THE ZERG'TH ELEMENT OF THE ARRAYS ARE USED, THEN

1 0 3 0 '■ IB M U S T ::;: Z E R 0 » E L S E IB ■■■■■■ 1 . N D » T H E MAX IM U M DIM E N S10 N

10'10 ' FOR EACH ARRAY (MAX VARIABLES>♦

10 5 0 IB-0 JND~15

1060 DIM RY(ND,IB>,R<NDtND> »X<ND»ND)»A<ND> #B<ND> ,B(NDtIB)

10 7 0 DIM IX(ND)jBECND)

1 0 8 0 C L S t P RINT " MULTIP L E I...INEAR REGRESSIGN PR0GRAM"

1090 PRINT "BY THOMAS Wr-u MADRON U.97'9)"

110 0 PRINT "2132 SAVANNAH TRAIL"

1110 PRINT "DENTON, TX 762 01"

1120 FOR I»0 TO SO 0 5 NEXT I

113 0 G O S U B 40 0 0 J N ■ N V - (1 -1B ) i N R:::: N t N C:::: NIG O S U B 3 0 0 0

1140 CLStINPUT "DO YOU WANT THE CORRELATION MATRIX REPRINTED"|Y$

1150 IF I... E F T $ ( Y $ , 1) ■■■■■■" Y " T H E N G O S U B 3 0 0 0

1160 CLStINPUT "VARIABLE NUMBER OF DEPENDENT VAR* FOR THIS RUN"}IY

1170 lY-IY-(l--IB)

113 0 INPUT"NUMBER OF INDEPENDENT VARIABLES IN THIS RUN"JNI

119 0 IF NIM>NV THEN PRINT "so TOO MANY VARIABLES K5K5K'1 {GOTO 116 0

12 0

121122

) PRINT "ENTER VARIABLE NUMBERS FOR INDEPENDENT VARIABLES'

) N-NI--(l-IB)

l F O R I ■■■■■■ IB T O N JIN P U T IM % IX (I) * IM - (1 -1B ) J NE X T I

50 MHz DIGITAL MEMORY OSCILLOSCOPEIN A PERSONAL COMPUTER

TWO CHANNEL DIGITAL MEMORYOSCILLOSCOPE. The Model 85provides two signal input chan-nels on one board and the timebase system on a separateboard. Both vertical channelshave a full 50 MHz bandwidth.Digitization is performed by high-speed sample and hold circuitryand an eight bit A/D converter toensure high resolution and ac-curacy.

FULLY PROGRAMMABLE. Auto-mated measurements werenever simpler. Programmablefeatures such as vertical attenua-tion, time base, trigger level,AC/DC/GND input and more,make the Model 85 a truelaboratory and factory qualityinstrument.

APPLE II* and APPLE II PLUS" COM-PATIBLE. The Model 85 DigitalMemory Oscilloscope plugsdirectly into the Apple II peripheralslots. Easily installed-just plug inthe vertical and horizontal boards,attach probe connectors, loadthe software, and you are readyto make precision measurements.

DIGITAL STORAGE. All the conven-ient features of digital storage:refresh display for easy viewing,precision measurements, un-limited storage time, signal pro-cessing, waveform storage ondisk. Now with the Model 85Oscilloscope and personal com-puter combination, you cancreate your own sophisticatedsignal analysis sytem.

Northwest Instrument Systems

P.O. Box 1309 • 1/503/297-7471Beaverton, Oregon 97075

NWIS

A NEW PERFORMANCE STANDARD.

The Model 85 Digital MemoryOscilloscope establishes a newperformance standard in instru-ment systems. Furthermore, pricedat less than SIOOO, it representsoutstanding value. For more infor-mation on the Model 85, send fora copy of our product brochureby writing:

'Trademark of Apple Computer Inc.

_..

—

, ,

-

li

I

?■»

'Dili

AC

t

jlji

If

)nS/

r c

pre

1 2

cursor= +44.2bTJ

NORTHWEST INSTRUMENT

SYSTEMSMODEL 85 OSCILLOSCOPE

438 Oclotwr 1981 © BYTE Publications Inc

Circle 269 on inquiry card.

Listing 2a continued:

123 0 N::::NI~( 1--IB)

12 q 0 F 0 R I ■ IB T 0 N ! K»-1X (I) : F 0 R J ~ X T Ci N

125 0 L~XX ( J ) » X (I f J ) =R ( K t I... ) ♦ X< Jt X) :::;X (I, J )

126 0 N E X T J t X < 11I) ■■■■■■■ 1» 0 J N E X T I

12 7 0 F 0 R I ~ IB T 0 N S J ■ IX (I) J R Y (I, IB ) ~ R (XY, J ) J N E X T I

12 8 0 G 0 S U & 6 0 0 0 t N :l.» N I N 2 === IB 5 N 3:::; N I G 0 S U B 2 0 (i 0129 0 AQ^A(IY)i R3~fl

13 0 0 F 0 R I»~ IB T G N l J ~ IX < X) 1 B E (I) ■ B (I, IB ) * < S CIY ) / S ( J ) )

1310 A 0 = A 0 ■•■• B E (X > * A (J > t R 3:::: R 3 + B ( X , X B ) - R Y « X 91B ) % NEX T X % R •'( - S Q R i R 3-)132 0 Fi*="VAR MEANS SXGMAS ZERO-R BETA B

13 3 0 F 2 * ='' t # t # # # # # # . # # # :lf # :ii: :li: # . # # * # * :i!: # :li; * # # *# # :li:* # # # # . # #13^0 FOR :i>T.B TO N STEP 10JJ»I+9

135 0 IF J>N THEN J«N

136 0 CI... Si PRINT TL$

137 0 PRINT Fl*

1380 FOR K«I TO J : I... ™ X'X < K )

J. 3 9 0 R 5 = R 3 - ( C B (K , IB ) 7 S Q R ( X ( K , K) )) ) C 2

1T D 0 P RINT U S X N G F 2* 11X ( K) + .1. t A < L > , S < I...) , R Y ( K , IB ) , B ( K ■> IB ) , B E (K), R5

1410 NEXT KJPRINT Q 96 0,"TYPE 'C TO CONTINUE";

1420 Y**INKEY**IF Y$«"C" THEN 1430 ELSE 1420

1430 NEXT I

R2-XCX)

1 q 5 0 P RIN T " MU I... T X i:;' i... E R « " ? R4 ? '* R - S Q U A R E D::::" IR 3

;l. •<}6 0 D1 = N11 D 2 = N S ■■•• ( N X ) ••■• 1 J F1 ~ (I1470 PRINT "FOR DF1~"?D1J"AN

'< 3 * D 2 ) / < (1 •- R 3 ) * D1 ) J G O S U B S 0 0 0

1480 PRINT "NUMBER OF OBSERVATIONS^"?NS

D2J"F»"|F1|"P™"JP

Listing 2a continued on page 440

V_

MX80-S4B9

APPLE GRAPHICS PARALLEL INTERFACE

Full Hi res Graphics for Epson, Okidata, etc.

ADDS

Viewpoint-$565ALTOS

ACS 8000-15 — $4750ANADEX

9500 — $1225 9501 — $1275ATARI

400 16K — $349 800 32K — $740

CENTRONICS

730 —$600 737 —$750

DATASOUTH

DS120 —$595 DS180 —$1295

DIABLO

630 —$2150 1640-$2575

DISKETTES

Scotch — $2.50 Dysan — $3.50

EPSONMX70 —$379 MX10O —$849

HAZELTINE1SOQ-$995 Esprit-$675

APPLE II

$89

-$1179 M83A-S875

TRS80 BIDIRECTIONAL I/O PORT

Cascadable with Selectable Addressing

$39

INTERFACES

SSM-AIO — $160 CPS-CARD — $199NORTHSTAR

HR64DD—$2895 HR64QD —$3280LOBO

Apple Driv.e/Card — $390/$90

TRS80 Drive/Interface — $260/$90

Apple DD Drive — $2740

MODEMS

HAYS-MICROMODEM - $325

Novation-Cat — $155Penril - 300/1200 (212A) — $795

MONITORS

APF —$125 SANYO-BW — $159

Sanyo-Green — $249 Color — $425

Amdek-Green —$159 Color —$350

MPI

88G —$595 9SG-$69S

NEC

5510 —$2540 5520 — $2900

SOROC

120 —$729 135 —$799SOFTWARE

All Major Brands — $CALL

televTdeo

912 — $669 950 — $949Tl

810 —$1475 820 —$1795

OKIDATA

M80 —$395 SL125-$3150M82A —$585 SL250 —$4200M83A —$875 M84 — $1175

XTRAS

Memory-16K 200ns — $19.95

Game Paddle Extension — $14.95

Game Paddles — $19.95

IDSI

Blue Break Out Box — $260

ZENITHZ19-$775 Z89 —$2195

DISCOUNT LINE1-800-528-8960

EXPOTEK CORPORATION INTERNATIONAL.

2231 West Shangri La Road, Phoenix, AZ 85029

ARIZONA 1-602-861-3181| EXPORT TWX- 910-950-1194

Circle 150 on inquiry card.

October 1981 © BYTE Publications Inc 439

Listing 2a continued:

1490 PRINT Q 960,"TYPE 'C TO CONTINUE"?

150 0 Y**INKEY*»IF Yi!i«"C" THEN 1510 ELSE 1500

15:!. 0 C I...S JIN PUT '' DQ YOU W A N T A N0T H E R RUN" J Y5 $

:!. 5 2 0 IF I... E F T * < Y 5 $ , 1 ) - " Y " T H E N 15 3 (J E I... S E C I... S J E N D

153 0 RUN

2 0 0 0 ' MA"fRIX MULTIPI...ICAT1.0N

2 0:1.0 ' Nl"NUMBER OF RONS IN B AND X, N2~~N UMBER OF

2 0 20 ' OF COLUMNS IN B AND RY« N3~NUMBER OF COLUMNS

203 0 ' IN X AND NUMBER OF RONS IN RY. SUBTRACT 1 FROM

2040 ' FROM EACH IF IB»0«

2050 FOR I*IB TO Nl

206 0 FOR J-IB TO N2

2 0 7 0 B (I, J ):::: 0

2030 FOR K-«IB TO N3

2 0 9 0 B (I, J ) ~B (I, J ) +X (I > K ) «RY < K , J )210 0 NEXT K

21:1.0 NEXT J

212 0 NEXT IS RETURN

30 0 0 ' SUBROUTINE TO PRINT A MATRIX

3010 ' NR"NUMBER OF RONS, NONUMBER OF COLUMNS, IF

3020 ' IB«0 THEN NR-NR-1 AND NONC-1 ♦ IB-STARTING

30 30 ' POINT FOR ARRAYS,

3 0 40 FOR I-IB TO NR STEP 10tIA*I+9tIF IA>-NR THEN IA~NR30 50 FOR J-XB TO NC STEP 9*JA-J+8JIF JA>«NC THEN JA==NC306 0 C L S {P RIN"f "CO R R E I... A T ION MAT R XX" t P RIN T T L *

3 0 7 0 F J. * « " V A R X'' IG :l. * «•'' # # ft ft'' J F 2 * ■'' ft ft ft ft " J C 2 $ ••= " t * . # ft''

30S0 PRINT F1$J

A REFURBISHED DAISY WHEEL TERMINALFOR PERSONAL COMPUTER USERS AND SMALL BUSINESSES.

Now you can have letter-quality printingand professional features for just $1,450?

AJ daisy wheel printer terminals are renowned for And you can choose from a list of options including

exceptional performance, high reliability, and applications forms tractor, pin-feed platen, paper trays, side shelves,

versatility. Now you can have all this for only $1,450* in our extra printwheels, APL keyboard and 2K buffer.

special limited offer.

• 30 cps letter-quality printing

• Changeable type faces

> Full ASCII keyboard withnumeric pad

■ High resolution X-Y plotting' Complete electronic forms

control

■ 128-character buffer

' Asynchronous RS-232 interface«Printwheel, ribbon cartridge,and cable included

• 30-day parts/labor warranty

aSI

Eis

Call your nearest AJ regionaloffice for details: San Jose, CA(408) 946-2900; Rosemont, IL

9(312)671-7155; Hackensack,NJ (201) 488-2525. Or checkthe phone book for the numberof your local AJ sales/serviceoffice.

'Price excludes options and is subject tochange without notice. Model shown includescertain options. Offer available only in thecontiguous U.S.

ANDERSON

JACOB5QN

440 October 1981 © BYTE Publications lnc

Circle 24 on inquiry card.

Listing 2a continued:

3 0 9 0 F 0 R L:::: J T 0 J A t P RIN T U 31N G G1 $ J I... + 1t % N E X"I" L X ? RIN T

3:1.0 0 FOR L*I TO IA

3 :l. :l. 0 p RIN T U SIN G F 2 * 11... + :l. 5 J F 0 R M:::: J T Q J A

3 :i. 2 0 P RIN' l' I. J SIN G G 2 $ |R<L»H>HN E XT Ml P RIN T I N E X T L

3130 PRINT 8 96 0,"TYPE 'C TO CONTINUE"J

3140 Y*»INKEY*iIF Yt>««"C" THEN 3150 ELSE 3140

315 0 NEXT JS NEXT I

316 0 RETURN

400 0 ' MATRIX INPUT FROM TAPE ROUTINE

't0.10 CMD"T,,tCLStPRINT "PREPARE MATRIX TAPE AND RECORDER1

'4020 PRINT @ 960, "TYPE 'C TO CONTINUE"?

4030 Y*«INKEY*JIF Y$~"C" THEN 4040 ELBE 4030

4040 INPUT #•4050 N*NV-<1-

■1*TL*JINPUT #-l,NV»NS

■IB)

4060 i::' O R I ■ IE T O N11N P U T 4 -1, A (I) , B (I) t N E X T I

1070 FOR I™IB TO NJFQft J™I TO N1IF I*J THEN 4090

4 080 INPUT *-l,R(I,J)

40 90 NEXT J J NEXT I

41 0 0 FOR I»IB TO N I FOR J■ I TO N S IF I:::: J THEN R (I, J ) «:l. J GOTO 411 0

el si:;: R(J,d=R(I»J)

4110 NEXT JtNEXT I

412 0 CHD"R"?RETURN

SO 0 0 ' PROPABILITY OF OCCURENCE OF F»T#Z»CHI-SQ

50 02 ' ADAPTED FROM DONALD J, VELDMAN, FORTRAN PROGRAMMING

50 04 '• FOR THE BEHAVIORAL SCIENCES (NEW YORK i HOLT, RINEHART

5006 ' AND WINSTON, 1967), PP♦ 129-131*

5 0 10 ' Dl, D2, Fl MUST BE SET BEFORE CALL Listing 2a continued on page 442

ADVANCED S-100 BUS PRODUCTS

LDP1/2

The LDP1/2 utilizes the advanced 8088 processor to provide up to 8times the throughput of a 4 MHz Z80A processor. The powerful instruc-tion set of the 8088 is ideally suited to higher level languages such asPASCAL and PL/1. The 10 slot motherboard leaves 7 slots for USER ex-pansion. With the option of a 10 MByte Winchester and MP/M-86, theLDP mainframe becomes a powerful multiuser system with the capabili-ty of handling 8 users without the degradation in performance experi-enced with Z80MP/M systems. The performance of the LDP1 and LDP2has never before been available for such an affordable price.

FEATURES:

— LDP88, 8088 CPU board

— LDP72, advanced floppy disk controller

— LDP64K dynamic RAM

— 1 serial RS232 port

— 10 slot motherboard

— 1 8" Shugart801R drive (LDP1), 2 Shugart 801R's(LDP2)

— 4K EPROM socket for user population

OPTIONS:

— HAZITALL

— 8" 10 MByte Winchester (replaces 1 Shugart 801 in LDP2)

— MP/M-86 multiuser system

— Woodgrained 7 slot chasis

PRICES

LDP88 CPU

LDP72 FDC

LDP64K RAM

LDP128K RAM

LDP256K RAM

HAZITALL

LDP1

86-DOS

CP/M-86

Microsoft BASIC 86

ASSEMBLED* TESTED

$ 349.95

274.95

695.001295.002095.00

325.003295.00

195.00

250.00

350.00

Call for LDP1 option prices and board kit prices.

CP/M-86 and MP/M-86 are trademarks of Digital Research86-DOS is a trademark of Seattle Computer Products

LDP88 8088 CPU BOARD

• 8088 CPU 5 MHz operation upgradeable to 8 MHz • 9 vectored inter-rupts • Fully complies with IEEE 696 electrical and timing specs

• RS232serial port with modem controls • 1 Kbytes of static RAM • 2EPROM sockets (2716 or 2732) • 8087 upgrade kit available in Sept.

• 8 bit bus eases interface to other S100 bus boards • 1MByte addressspace • 65K I/O ports

64/256K MEMORY

• 8 or 16 bit operation • Meets all IEEE 696 specs • Access time350 ns from PSYNC low • Intel 8203 dynamic RAM controller • 24 or16 bit address decoding • No wait states with 5 MHz 8088 or 8086

• Parity with Error interrupt generation • No DMA RESTRICTIONS

• 64K board is upgradeable to 256Kbyte board

HAZITALL

• 2 Serial RS232 ports • 2 parallel ports with handshake control

• Math processor support (8231/9511 or 8232/9512) • WINCHESTERDISK support • Real time programmable interrupt • Clock/calendarwith battery back up • Synchronous data communication supported

LDP72 FLOPPY DISK CONTROLLER

• IBM compatible single and double density format • Single or doublesided drives • Programmable data record length (128 to 8192 bytes/sector) • Multi sector and multi track transfer capability • Parallelseeks on up to 4 drives • On board digital data separator • Softwareselectable single or double density operation • Separate connectorsfor 5Vi" and 8 drives • Software selection of standard or minidrivesallowing mixing of both drives on a single controller

LOMAS

DATA

PRODUCTS

11 Cross StreetWestborough, MA 01581Telephone (617) 366-4335

Circle 204 on inquiry card.

October 1981 © BYTE Publications Inc 441

Listing 2a

50205 0 3 0504050 5050605 0 7 05 0 B 0

50 9 0

51 0 0

51 :l. 05120

513 0

514 0

515 0

516 05170

518 0

519 0

52 0 052105220

523 0

524 0

525 0 PI

52706!) 0 0

continued:

' S IS RETURNED AS SIGNIFICANCE LEVEL

P1 ■ 1, 0

IF Dl * D2 * El :::: 0 , 0 THEN 526 0

IF El < 1*0 THEN 510 0

A => D1

B :::; D2

F -™ El

GOTO 5130

A » D2

B - Dl

F - 1. 0 / F1

A1 - 2,0 / (9,0 * A)

B1 :::: 2,0 / (9,0 * B)

X ■ (Ci.,0 •••• Bl) * EC, 3 3 333 3 -■ 1,0 + Al )

Y ■■■■ SQR(B1 « PC*666667 + Al)

Z ■ ADS(X / Y)

IF B < 4,0 THEN 52 0 0

GOTO 5210

z « z * (1*0 •*• ,08 ;« zi::4 / bi:,3)

Zl ■ ( »115194+Zx< ,000344-t-Z*, 019527) )Pl« ,5/(1, 0+Z*< , 196854-:-Zx;Zl) ) C4IF El < 1,0 THEN 5250GOTO 526 0

» 1,0 ■■■• PIP»PiRETURN' MATRIX INVERSION USING EXCHANGE METHOD

DISK 111

100% Compatible

Model III Disks

Disk III SingleDrive Assy.1$599.00

Disk III DualDrive Assy.$864.00IMMEDIATE DELIVERY COMPARE & SAVE

VR DATA'S Disk III features:

• Completely compatible w/TRSDOS™

• State-of-the-art circuitry.

• Fully tested, calibrated and burned in.

• Warranty 120 days

• Installation with simple hand tools

• Optional dual side and/or 80tk.

• Conforms to FCC Class B Specs.

'DISK III single drive assembly includes: one 40 track5Vi" double density drive, power supply, controller,mounting hardware, and applicable cables.Prices subject to change without notice.r^^» ■■■

^SzSala

777 Henderson BoulevardFolcroft, PA 19032

' OD AlddflS MSICT

iet>S-I91> (9lZ)t E9061 Vd 'B!P3W • »S 3^!IO S111 • 6£\r aJins

aapjo urai 00001$aBueip oj pafqns saouj paisi| }ou sui3}i uo saoud joj \\vq

ttvd saavoasoDJOHNimnj

00-S0I$ W3CIOWNODIX31

H3J30 pa*!"»n 3VI33dS

OO'LKli

OO'OUfc

00"06S$

00'0S9ct

0017812$

00"66f7l$

9099 eJerj [BJfiajuj

OOIXWNOSdH

JL308XW 00'06l7$08XWNOSd3

•Dei}/moe5S/OISS33N

•DBii/mos9 0igvia

•dgji/m(sdo gg) H3IIHMHV1S HOII 33AIHai-M8fr/68ZHlIN3ZaD 00"0W2$ NIVH9H3dnS Mt>9

oo"ozz$ wo-'didw/NoaNvi/oacn-ssAiHa

S3JU(] 3|duiG§

0g"TOZZ$

00-0662$

:pg ipeius

To order coll toll free-( 800) 345-8102 or (215) 461-5300 In PA.

442 October 1981 © BYTE Publications Inc

Circle 401 on inquiry card.

Listing 2a continued:

6 010 ' N, IE MUST BE SET PRIOR TO CALL

6 0 2 0 IF N>ND THEN 603!) ELSE 6050

6 030 PRINT "MATRIX SIZE IS LIMITED TQ"JND

6 0 °t 0 P R INT " Y 0 U l-l A V E A SIZ E 0 F " % NI E N D

6050 FOR K-IB TO NSD<*-1/X<K»K)

60 6 0 FOR J-IB TO NSIF J«K THEN 60SO

6070 X<K»J)«X<K»J)*D

60 80 NEXT J

60 90 D=~D

610 0 FOR I~IB TO NJIF I»K THEN 6:1.60

6110 E-X(I»K)

612 0 FOR J™IB TO NJIF J«K THEN 6140

6130 X(I,J)»X(I,J)+XCK tJ>xEI GOTO 615 0

6140 X(X,K)»X(X»K>*D

6150 NEXT J

616 0 NEXT I

617 0 X ( K , K ) ~~ D J N E X T K i R E T U R N

(2b)

>RUN

M UI-. TIP!... E LIN E A R R E G R E E SIO N i::' R O G R A M

B Y T l-l O M A S W M , M A D R O N (1979)

2132 SAVANNAH TRAIL

DENTON, TX 76201

PREPARE MATRIX TAPE AND RECORDER

7 Y P E ' C ' T O C O N TIN U E C O R E E i... A TIO N M A T RIX

Listing 2b continued on page 444

How can Carrel"teach Alice aboutWonderland?

As a trainer you should know!

The Coloney Intelligent Learning Carrel™ is the answerto your individualized training needs.

Carrel™ is a custom-built student learning station that contains an exciting newinteractive video system. Now you can have the power of computer assisted andcomputer managed instruction with the impact of high speed access to video.The system includes: the Apple II Plus™ microcomputer, a laser reflectivevideodisc player, a color monitor and the Coloney Interface Package. A newlearning experience awaits your students in the wonderland of computercontrolled stereo sound, beautiful high resolution video and colorful computergraphics. An ever patient Carrel™ coaxes, questions, and delights whileanswering your student's needs in an individualized learning environment.Best of all, Carrel™ is inexpensive. At Coloney we continue to giveyou reasons to make us your number one choice in interactive training.

Apple II Plus Is a registered trademark of Apple Computer Inc.

The Coloney Intelligent Learning Carrel and Carrel are trademarks of Coloney Productions

COLONEYPRODUCTIONS

1248 Blountstow/n Hwy. Tallahassee. Fl 32304 [904] 5750691

Circle 70 on inquiry card.

October 1981 © BYTE Publications lnc 443

Listing 2b continued:

TEST DATA

VAR1 1 2 3

1 1,0 0 -0,01 0*47

2 --0*01 1*00 0,37

3 0*T7 0,37 1,0 0

TYPE 'C TO CONTINUEDO YOU WANT THE CORRELATION MATRIX REPRINTED? NVARIABLE NUMBER OF DEPENDENT VfjR. FOR THIS RUN? 3NUMBER OF INDEPENDENT VARIABLES IN THIS RUN? 2ENTER VARIABLE NUMBERS FDR INDEPENDENT VARIABLES',) -i

TEST DATA

VAR MEANS

1 26*1?

2 27,25

STOMAS ZERO-R BETA"1*81 0*4743 0*4791

1*7? 0*367? 0*37^0

B R2--X(I>1*1? 0,13542.50 0*225 0

TYPE 'C TO CONTINUETEST DATA

INTERCEPT- 107*825

MULTIPLE R~ »6040 04 R-SGUARED- ,364821

FOR DEI- 2 AND DF2« 13 F-~ 3*73383 P~ ,0514039

NUMBER OF OBSERVATIONS- 16

TYPE 'C TO CONTINUEDO YOU HANI ANOTHER RUN? N

READY

PRICE BREAKTHROUGH

I6K RAM BOARDS FORAPPLE JUST $129.95

HAVE VOU BEEN WAITING FOR THE COSTOF EXPANSION BOARDS TO COME DOWN?VOUR WAIT IS OVER. UP UNTIL NOW BAMEXPANSION HAS COST AS MUCH AS$195.00. NOW OMEGA MICROWARE ISPROUD TO ANNOUNCE THE ARRIVAL OF ATRULV AFFORDABLE EXPANSION CARD.

NOW VOU CAN RUN PASCAL, FORTRAN,56K CPM WITH A Z80 SOFTCARD,INTEGER BASIC, APPLESOFT AND OTHERLANGUAGES ON VOUR APPLE. NOW VOUCAN INCREASE USUABLE MEMORV FORVISICALC. NOW VOU DON'T HAVE TO PAN AFORTUNE TO HAVE ALL THIS.

AT $129.95, OMEGAS RAMEX 16 IS THE

LOWEST PRICED CARD AVAILABLETODAV.

WHAT DO VOU GIVE UP WHEN VOUPURCHASE THIS FIRST REALLVAFFORDABLE RAM EXPANSION CARD?WELL, VOU GIVE UP HAVING TO REMOVEONE RAM CHIP FROM THE MOTHER BOARDOF VOUR APPLE. VOU GIVE UP HAVING TOSTRAP A CABLE FROM THE CARD TO VOURMOTHER BOARD. THAT'S IT. WHAT VOUGET IS A SIMPLE, RELIABLE, BOARDTHAT JUST PLUGS IN. MEMORV REFRESHIS ACCOMPLISHED ON THE BOARDITSELF.

THE RAMEX 16 IS GUARANTEED NOT JUSTFOR 90 DA VS. NOT EVEN 6 MONTHS OURWARRANTV IS FOR ONE FULL VEAR FROMDATE OF PURCHASE. WE WILL REPAIR ORREPLACE ANV BOARD THAT IS DEFECTIVETHROUGH MANUFACTURE FOR A PERIODOF ONE VEAR AFTER PURCHASE PROVIDEDTHIS DAMAGE IS NOT USER INFLICTED.

ORDER VOUR RAMEX 16 NOW BV CALLINGTOLL FREE 1-800-835-2246. KANSASRESIDENTS CALL 1-800-362-2421.MASTERCARD OR VISA ACCEPTED ORSEND $129.95. ILLINOIS RESIDENTS ADD$7.80 SALES TAX.

ANOTHER QUALITV PRODUCT FROMOMEGA MICROWARE, INC.

FORMERLV omega SOFTWAREPRODUCTS,INC.222 SO. RIVERSIDE PLAZACHICAGO, IL 60606PHONE 312-648-1944

©OMEGA MICROWARE, INC.

APPLE AND APPLESOFT ARE REGISTEREDTRADEMARKS OF APPLE COMPUTES. INC. PASCAL IS AREGISTERED TRADEMARK OF THE REGENTS OF THEUNIV. OF CA. SAN DIEGO. VISICALC IS A REGISTEREDTRADEMARK OF PERSONAL SOFTWARE. CPM IS AREGISTERED TRADEMARK OF DIGITAL RESEARCH INC.ZSO IS A REGISTERED TRADMARk OF ZIlOG INC.SOFTCARD IS A REGISTERED TRADMARk OFMICROSOFT.

^

444 October 1981 © BYTE Publications Inc

Circle 276 on inquiry card.

Circle 87 on inquiry card.

Correlation Program

Line

Numbers

Routine

1000-1170

main program

3000-3160

matrix-printing subroutine

4000-4570

correlation-matrix subroutine

4120-4200

read correlation parameters

4210-4470

data-input routine

4480-4570

matrix-tape-output routineRegression Program

Line

Numbers

Routine

1000-1530

main program

2000-2120

matrix-multiplication subroutine

3000-3160

matrix-printing subroutine

4000-4120

matrix input from tape

5000-5270

probability-of-occurrence subroutine

6000-6170

matrix-inversion subroutine

Table 1: Organization of the correlation and regression programs.

The main dif-

ference between the two is in the subroutines that begin at line 4000.

It is impossible

to consolidate the two into

a single program (see text for details).

Text continued from page 431:

gram and a series of subroutines (easi-ly noted in the listings).

Modifying the Programs

The correlation program and theregression program are similarlyorganized (see table 1), but the latterreads data exclusively from a tape filegenerated by the correlation pro-gram. If a consolidated program ispreferred, the correlation subroutinein the correlation program can besubstituted for the matrix-input-from-tape subroutine in the regres-sion program. Both subroutines beginat line 4000 in their respective pro-grams. A consolidated program takesonly about 6 K bytes of memory.

Because the program is based onmatrix algebra, several of thesubroutines can be replaced withBASIC matrix functions. While LevelII BASIC for the TRS-80 has nomatrix functions, it is possible to ob-tain a software package (from RacetComputes of Orange, California) thatprovides those functions. And otherBASICs, of course, may have thefunctions. For example, with theRacet functions, the matrix-inversionsubroutine (lines 6000 through 617C)of the regression program could bechanged to the following:

6000 ' MATRIX INVERSION

6010 I = &MINV(R,X,NV-1,D1,D2): RETURN

Or in a DEC (Digital Equipment Cor-poration) BASIC system, it might ap-pear as follows:

6000 ' MATRIX INVERSION

6010 MAT C = INV(R)

6020 RETURN

In both cases, some other (minor)changes would have to be made to themain program, but both techniquescould be used. Built-in matrix func-tions, such as the example from DEC,do not typically use the zeroth row orcolumn of arrays, thus wasting con-siderable memory. If these programsare implemented using such func-tions, however, the variable IB (line1050) can simply be changed to 1,thus eliminating the use of the zerothrow and column throughout the pro-gram. The Racet functions use thezeroth row and column, and IBwould be left unchanged. Bear inmind that these are only examplesand that if the matrix functions areavailable, the program might besimplified in other ways as well.

Since arrays in Level II BASIC canbe dynamically dimensioned, avariable (ND) is also set in line 1050to the largest number of variablesthat might be contained with anygiven memory size. Even in a

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16 K-byte machine, the dimen-sionality could be expanded beyondthe default (ND = 15). Parametersfor each problem are established con-versationally in both programs, andparameters for regression can befound in lines 1130 through 1220.Questions requiring a yes or noanswer can be answered with either"Y" or "YES" or "N" or "NO".

Data needed by the regression pro-gram includes the sequential numberof the dependent variable in the run(a sequential number from 1 to thetotal number of variables correlated),the number of independent variables(any number from 1 to the totalnumber of independent variables forthe run), and the sequential variablenumbers of NI, the number of in-dependent variables. The program isstructured so that at the end of a run,the user is asked if there will beanother run (from some subset of thevariables correlated). This capacity isespecially useful when doing ac-tivities such as causal modeling.All printing, whether of the cor-

relation matrix or other elements ofthe analysis, is formatted to fit thedisplay screen of the TRS-80 (16 linesby 64 characters). The display isstopped at various stages throughoutthe program and information is com-municated to the user with thefollowing BASIC statements:

xxxx PRINT @ 960, "TYPE 'C TO

CONTINUE";yyyy Y$ = INKEY$: IF Y$ = "C"

THEN zzzz ELSE yyyyzzzz next line

Many BASICs may not have theINKEY$ function that accepts inputfrom the keyboard without waitingfor the Enter or Return key to bepressed. To work properly, it must beplaced in a loop, as illustrated. ThePRINT @ 960 statement prints themessage at position 960 (the 16th lineof the display) on the screen.

Actual calculation of the statisticsfor the regression begins at line 1230.The correlation matrix R(IJ) is subsetinto X(I,J), which includes only the

independent variables for the run(lines 1230 through 1260). ArrayX(IJ) is inverted to provide the infor-mation necessary to calculate the b*s.The call to the matrix inversionroutine is at line 1280 (GOSUB 6000).In lines 1290 through 1460, severalstatistics are calculated and displayedfor each independent variable, in-cluding the mean, standard devia-tion, zero-order correlations with thedependent variable, b*, b, and R2with the variable deleted. The laststatistic is useful in evaluating the im-pact of a given independent variableon the total regression. Finally, thesummary regression statistics arecalculated and printed in lines 1440through 1490, including the intercepta, R, R2, F, degrees of freedom for F,and p (the probability of occurrenceof F). The probability is calculatedwith a call to the probabilitysubroutine (GOSUB 5000). The ra-tionale for the computationalalgorithm is given in Veldman's book(reference 5, pages 129 through 131).The same subroutine can also be used

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to calculate the probability of occur-rence for f statistics, z, and chi-square(see reference 5). The program thentests for another run or terminates ex-ecution (lines 1510 through 1520).

Extensions and Modifications

If the computer being used is aRadio Shack TRS-80 Model I, thecorrelation and regression programswill run as presented here. If the pro-gram is being implemented onanother computer, it is likely thatmost of the screen-formattingroutines will have to be changed. Asmentioned above, the regression pro-gram can be simplified by replacingthe matrix subroutines with machine-language matrix functions (such asthose from Racet) or with nativefunctions (such as exist in DECBASIC). The number of variablesthat can be used by the program canbe increased or decreased by chang-ing only the initialized value of ND inline 1050 of both programs. Thenumber of variables depends onmemory size, but even on a16 K-byte machine the number couldbe increased significantly.

All I/O of original data is handledin the correlation-matrix subroutinewith calls to internal subprograms. Ifa floppy-disk drive is available, adecided advantage can be gained bysaving the data and matrix on diskrather than on tape. Because thematrix can be saved, it can be usedfor input not only to regression butalso to other programs. One possibleaddition to regression might be to adda routine to allow input of the means,standard deviations, and correlationmatrix from the keyboard so thatpublished matrices might be ana-lyzed. The original input data canalso be saved on tape and could beused in the regression program tocalculate predicted values of Y andresiduals.

The keyboard data-entry routine(beginning at line 4210 of the correla-tion program) is rather primitive andincludes no means for verifying theveracity of the data—such a checkmethod might be a useful addition tothe program. While there are tech-niques for calculating a multiple re-

gression other than the one presentedhere, one of the primary strengths ofthis approach is that the regression isactually calculated from the correla-tion matrix. Consequently, it is possi-ble to calculate correlations whensome data is missing (different Ns fordifferent pairs of variables).

There are pitfalls when doing this,but unless there is a lot of missingdata (especially on large samples), itis quite useful. The actual correlationroutine could be modified to handlemissing data, and perhaps somescheme for differentially weightingobservations might be included toallow the user to modify variousdistributions. Again, some cautionshould be exercised when doing suchmodifications to the data. In anyevent, if such modifications aremade, they need be made only in thecorrelation subroutine—the regres-sion program need not be touched.

As a final note, the varioussubroutines provided in this programare sufficiently general so that theycan be used in other programs de-

signed by the reader. In fact, only thecalling program is specific to theregression or correlation functions. Itwould save time to build a subroutinelibrary that could have general ap-plicability. Although Level II BASICdoes not provide the means formerging all or part of programs fromtape to existing programs in memory(Radio Shack Disk BASIC does havea merge function), several softwarevendors currently supply suchutilities that will do the job nicely. ■

References

1. Adler, Alfred. "The Micro-Mathematician.'Interface Age. October 1979, page 39(Includes a discussion of matrix algebra.)

2. Adler, Alfred. "The Micro-Mathematician.'Interface Age. November 1979, page 30(Discusses matrix inversion.)

3. Kerlinger, Fred N and Elazer J PedhazurMultiple Regression in BehavioralResearch. New York: Holt, Rinehart andWinston, 1973. (See especially chapters 3and 4.)

4. Racet Computes. Infinite BASIC. (Matrixand string package for the TRS-80). 702Palmdale, Orange, CA 92665.

5. Veldman, Donald. FORTRAN Program-ming for the Behavioral Sciences. NewYork: Holt, Rinehart and Winston, 1967.

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October 1981 © BYTE Publications Inc 447

Bits and Bytes in Pascal

There are no "secrets" in this article.I will simply show you some tricksthat can be performed with UCSDPascal. Like many programmingtricks, these are of interest for twomain reasons: to ease complicatedsystem programming and to en-courage fun programming.

All of the facts that I use can befound in the documentation availablefor UCSD Pascal (developed at theUniversity of California at SanDiego). However, these features havebeen documented very lightly up tonow, with little or no explanation.Before I attempt to explain them Iwant to cover myself as follows:everything in this article has beentested with Apple II Pascal (both theoriginal release and the current Ver-sion 1.1). Except as noted, I believe itshould apply to other versions ofUCSD Pascal—but I don't guaranteeit.

Be warned: If you employ thesetricks, you will abandon some of thesafety features of the language. Thiscould easily result in incomprehensi-ble bugs in your program. Even if theprogram works correctly, you mayrun into trouble when you try tomodify it. You should also be awarethat tricks that work with your pre-sent system may not work with anupdated version. Furthermore, thepeople who sold you your UCSDPascal are under no obligation to sup-port any features that they don'tdocument themselves.

And OtherBinary Wonders

David CasseresApple Computer Inc

10260 Bandley DrCupertino CA 95014

However, if you study these tricksyou'll be able to do some things thatare otherwise impossible. You'll alsogain some insights into how thesystem works when it runs a Pascalprogram. You will find that yourPascal program can treat memory asa collection of bytes, which are inturn made up of bits; that data typesare more changeable than they ap-pear; that AND, OR, and NOT aremore powerful than you thought; andthat you can access specific machinelocations in the same way you wouldwith the PEEK and POKE keywordsof BASIC.

Background

The original definition of Pascal iscontained in the Pascal User Manualand Report by Kathleen Jensen andNiklaus Wirth. I call this originaldefinition Classical Pascal, in order todistinguish it from UCSD Pascal.Classical Pascal was intended for useas a teaching language, and as such itembodies many features that support"good" programming practice. It evenhas features that enforce good prac-tice.

Good practice, in programming oranything else, depends on what

you're trying to achieve. For example,suppose you're developing a driverprogram for an exotic peripheraldevice. The question is, can you dothe job conveniently and efficientlywith normal good-practice program-ming in Classical Pascal? And theanswer is, you could —but you'dprefer to circumvent the strictures ofClassical Pascal. Perhaps you'd liketo treat an integer value as an array ofbits, or access a machine location byits physical address without usingmachine language.

A major assumption of ClassicalPascal philosophy is strong typing(ie: any value represents data of onetype only, and it cannot be directlyinterpreted as if it were of anothertype). Jensen and Wirth did provide amechanism for defeating strongtyping —the free-union recordvariant —but they didn't explain itsuse in the Pascal User Manual andReport. I will do so later in thisarticle.

Another assumption of ClassicalPascal is that there are only twoboolean values, represented by thebuilt-in constants TRUE and FALSE.But in UCSD Pascal, a boolean valuecan actually be any pattern of 16 bitsand it is interpreted as either true orfalse. The boolean operators AND,OR, and NOT are usually assumedto do single operations on values ofTRUE and FALSE; actually, how-ever, they are bitwise logical oper-ators with 16-bit operands. This per-

448 October 1981 © BYTE Publications Inc

mits some uses of boolean values andoperations that are normally not con-sidered part of Pascal.

Representing Scalar Values

In order to understand and applythese special techniques, you need toknow how some of the data types arerepresented internally. The followingsections provide details on how datais represented in binary for eachscalar data type. A later section dealswith arrays. (By the way, when I say"scalar" I don't include the real-datatype. Jensen and Wirth define the realtype as a scalar type, but then theycontinually modify by saying "anyscalar type except real." The fact isthat real types are not very similar toother scalar types and I consider thema different category. If you're apurist, you can whisper "except real"each time the word "scalar" appears.)The basic unit of storage in UCSDPascal software is a 16-bit word thatconsists of two 8-bit bytes (on mostmicrocomputers). The least-signifi-

HIGHER-NUMBERED BYTE

LOWER-NUMBERED BYTE

f

\

(

>

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0J

BIT NUMBERS

Figure I: Representation of a 16-bit word in UCSD Pascal. Every nonpacked scalarvalue is represented as two 8-bit bytes; least-significant bits are stored in the lower-numbered byte, while most-significant bits are stored in the higher-numbered byte.

cant byte is at the lower of the twobyte addresses. Figure 1 shows howto visualize a word; the least-signifi-cant bit is bit 0. Every nonpackedscalar value is represented in oneword, as a 16-bit binary number.

Integers

An integer value is represented inone word as a binary number, withthe least-significant bits in the low-numbered byte. Two's-complementnotation is used to represent negativeintegers; thus, the most-significant bitof the binary number is a sign bit forthe integer. If it is a 1, the integer

value is negative and must be inter-preted accordingly (see table 1).

Characters

A character is represented in oneword by its ASCII (American Stan-dard Code for Information Inter-change) code. Since ASCII codes arein the range 0 through 255, they onlyrequire 1 byte; the character code isrepresented in the low-numbered byteof the word. (The most-significantbyte contains Os.)

Booleans

A boolean value is represented in

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IntegerValue

Stored Number

Decimal Hexadecimal

3276632767

- 32768■ 32767

3276632767

3276832769

7FFE7FFF

80008001

(2"-1)

(2")

-2 65534 FFFE

-1 65535 FFFF (2'6-1)

Table 1: Two's-complement notation.Both positive and negative integers arerepresented by using the most-significant bit as a sign bit. Negative in-tegers are represented as binarynumbers in the range 32768 to 65535.

one word. The logical true or falsevalue is represented by the least-significant bit of the least-significantbyte. For most purposes, this is theonly meaningful bit and all others areignored —but read on.

User-Defined Scalars

When you declare a user-definedscalar type, each of its value identi-fiers is associated with an ordinalityvalue; the first one declared has anordinality of 0, the next has an or-dinality of 1, and so forth. For exam-ple, the declaration:

VAR DAY: (MON, TUES, WED,THURS, FRI, SAT, SUN);

creates a variable DAY whose possi-ble values (at the source programlevel) are MON through SUN. Theseare associated with the ordinalities 0through 6; thus, MON correspondsto 0, TUES corresponds to 1, andSUN corresponds to 6. If DAY is as-signed a particular value, such as thefollowing:

DAY:= WED

the value is represented in binary asthe number 2, because WED cor-responds to 2.

Implications

By combining this information on

450 October 1981 © BYTE Publications Inc

Circle 92 on inquiry card.

representation of scalars with thefollowing facts about the ORD andODD functions, you can do some in-teresting things.

The ORD and ODD Functions

The familiar ORD function acceptsa noninteger scalar value as its pa-rameter, and returns an integer whichis the ordinality of that value withinits type. This is done in a strikinglysimple way: ORD merely returns thevery same value that was passed to it,and since ORD is, by definition, aninteger function, the returned value isnow interpreted as an integer. Themethod works because every non-packed scalar value is represented inthe same way: as a 16-bit binarynumber. The integer value of thebinary number is the ordinality of thescalar value.

The ODD function accepts any in-teger as its parameter; it returns trueif the integer is odd, and false if theinteger is even. Notice that odd andeven depend only on the last bit of aninteger value (you will recall that true

and false depend only on the last bitof a boolean value). ODD actuallyreturns the same value that, waspassed to it; since ODD is, by defini-tion, a boolean function, the returnedvalue is now interpreted as a booleanvalue.

This implies that the binary form ofany scalar value can be interpretedaccording to its original type, or as aninteger, or as a boolean value.Accordingly:

• To interpret the binary value of anynoninteger scalar S as an integer, useORDS(S).

• To interpret the binary value of anyinteger N as a boolean, use ODD(N).

• To interpret the binary value of anynoninteger scalar X as a boolean, useODD(ORD(X)).

Incidentally, the SUCC and PREDfunctions work by simply increment-ing or decrementing the binary valueof a scalar (its ordinality) and return-ing the result as a scalar of the sametype.

The program BITFIDDLER (listing1) is a simple-minded application ofthese ideas. It allows you to see an in-teger value as a list of bit values, set aselected bit, and clear a selected bit.In order to do this, it makes use of thefact that AND, OR, and NOT are16-bit operations. It sets up an arrayof 16 integer values, each of whichhas a 1 in one particular bit and Os inall other bits (the values are powers of2).

Each of these power-of-2 valuescan be used in the TSTBIT function totest the corresponding bit of an in-teger via the AND operation. Theresult of the AND is a nonzero integerif the tested bit is a 1, and a 0 integerif the bit is a 0. The SETBIT pro-cedure sets a bit by using the OR op-eration, and the CLEARBIT pro-cedure clears a bit by using ANDNOT.

To make these operations possible,the integer values must first be con-verted to type boolean by the ODDfunction. Then the boolean operation(AND, OR, or AND NOT) is per-

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Listing 1: The BITF1DDLER program uses the ODD and ORD functions to manipulatedata types. In the TSTBIT function and the SETBIT and CLEARB1T procedures, ODDis used to convert integer values into type boolean so that a bitwise boolean operationcan be performed. (ORD then converts the result back to type integer.)

PROGRAM BITFIDDLER;(*This program takes an integer value from the keyboard anddisplays its value as a list of 16 bit values. Then itsets a specified bit, displays the bit values again, clearsa specified bit, and displays once more: *)

(*Declare a subrange type for indexing the bits ofan integer value:*)

TYPE BITNUMBER = 0..15;

(*Declare an array of 16 integers — one for each bit

of an integer value:*)

VAR BITVAL: ARRAY [BITNUMBER] OF INTEGER;I: BITNUMBER;INNUM, NUMBER: INTEGER;

(*A procedure to initialize the array so that each BITVAL[I] has a1 in bit I and 0's in all other bits:*)PROCEDURE INITIALIZE;VAR I:BITNUMBER;BEGIN

BITVAL [0] := 1;

FOR I := 1 TO 15 DO BITVAL[I] := 2*BITVAL[1-1]END;

(*A function to return true if a particular bit of an integer valueis a 1, or false if the bit is a 0:*)

FUNCTION TSTBIT (BITPOS: BITNUMBER; N: INTEGER): BOOLEAN;BEGIN

TSTBIT := ORD(

ODD(N)AND

ODD(BITVAL[BITPOS]))<> 0END;

(*A procedure to analyze an integer value and report each bit:*)PROCEDURE ANALYZE(N: INTEGER);VAR I: BITNUMBER;BEGIN

FOR I := 0 TO 15 DO BEGIN

WRITE('Bit ', I, ' of ', N, ' is a ');IF TSTBIT(I, N) THEN WRITELN('l')ELSE WRITELN('0')END;END;

(*A procedure to set (to 1) a particular bit of an integer variable:*)PROCEDURE SETBIT (BITPOS: BITNUMBER; VAR N: INTEGER);BEGIN

N := 0RD(

ODD(N)OR

ODD(BITVAL [BITPOS] ))END;

(*A procedure to clear (to 0) a particular bit ofPROCEDURE CLEARBIT (BITPOS: BITNUMBER; VAR N:BEGIN

N := ORD(

ODD(N)AND NOT

ODD(BITVAL [BITPOS] ))

an integer variable:*)INTEGER):

END;

Listing 1 continued on page 453

formed. This gives a boolean result,which is converted back to type in-teger by the ORD function.

The boolean constants FALSE andTRUE are always represented as the16-bit binary numbers 0 and 1,respectively. ORD(FALSE) is 0 andORD(TRUE) is 1. In other words,FALSE has Os in all 16 bits, whileTRUE has a 1 in the least-significantbit and Os in the other 15 bits.

As the BITFIDDLER programshows, there are other boolean valuesbesides FALSE and TRUE —valuesthat have Is in other bit positionsbesides bit 0. I call these other valuesstrange boolean values. For example,ODD(3) is a boolean true value but itis strange —it is represented by the16-bit binary number for 3, not 1. Ithas Is in both bit 0 and bit 1.

Use of Strange Booleans

In the BITFIDDLER program, wedeliberately created strange booleanvalues, but you should be aware thata strange value can arise inadver-tently. As shown above, ODD of anyinteger except 0 or 1 will give astrange value; the result is alsostrange when you complement a nor-mal boolean value by using the NOToperator, because Is appear in bits 1through 15. In both of these cases,Classical Pascal says the result shouldbe either TRUE or FALSE.

You might wonder how strangeboolean values can work correctly inIF, WHILE, and REPEAT statements.They work because the systemignores all bits except the least-significant bit when it looks at theboolean value in an IF, WHILE, orREPEAT. Similarly, when twoboolean values are compared, all bitsexcept the least-significant bit areignored.

But Classical Pascal allows other,less obvious uses of boolean values:

• A CASE statement can be controlledby a boolean value (with cases la-beled TRUE and FALSE).

• An array index can be of typeboolean.

• A FOR statement can have a booleancontrol variable that goes from oneboolean value TO (or DOWNTO)

452 October 1981 © BYTE Publications Inc

Listing 1 continued:

BEGIN

INITIALIZE;INNUM := 1;REPEAT(*Get- number from user:*)

WRITE('Type an integer (-100 to quit-): '); READLN (INNUM) ;NUMBER := INNUM;(*Demonstrate testing the bits:*)

ANALYZE(NUMBER);(*Demonstrafe setting a bit:*)

WRITE('Set what bit in the value ', NUMBER, '? '); READLN(I);SETBIT(I, NUMBER);ANALYZE(NUMBER);(*Demonstrate clearing a bit:*)

WRITE('Clear what bit in the value ', NUMBER, ">. '); READLN(I):CLEARBIT(I, NUMBER);ANALYZE(NUMBER)UNTIL INNUM = -100END.

another boolean value.• A set of booleans whose possiblemembers are the values TRUE andFALSE can be declared.

These uses may seem unusual, butthey're normal in the sense that theyare part of Classical Pascal. How dothese uses work when a strangeboolean value is involved?

You'll have to determine thisanswer for yourself, by experimenta-tion. There are now so many versionsof UCSD Pascal that I don't knowhow each of them deals with, say, astrange boolean value used as anarray index. Some versions cannothandle strange boolean values inthese situations. (The current Version1.1 release of Apple II Pascal does

handle strange boolean values cor-rectly in all cases.)

Representation of Arrays

A nonpacked array of scalar valuesis represented simply as a sequence ofwords, with each word containingone scalar value as previouslydescribed.

When the array is packed, eachvalue does not necessarily take upone word. The word is still the unit ofstorage, but each word can containmore than one value if it has enoughbits. Consider the declaration:

VAR OCTAL: PACKED ARRAY(0..63]OF0..7;

which creates an array OCTAL of 64elements. Each element is an integervalue in the range of 0 through 7, andrequires 3 bits. Since a word contains16 bits, 5 array elements can bepacked into a word. The elements arepacked so that the first element is inbits 0 through 2, the second is in bits 3through 5, and so on, to the fifth ele-

^M.i^kp^'^0^4h^i,k^;)t-'i^m

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Ilia

October 1981 © BYTE Publications Inc 453

ment in bits 12 through 14. Bit 15 isunused. The next element goes in bits0 through 2 of the next word.

The following specific cases are ofparticular interest:

• A char value requires 8 bits. In apacked array of char, each word ofstorage contains two char values: thefirst is in bits 0 through 7, the secondin bits 8 through 15.

• A value of the subrange type 0..255also requires 8 bits and can bethought of as a "byte"-type value.

Storage in a packed array of 0..255 isthe same as for packed char values.• A boolean value requires only onebit; in a packed array of boolean,each word contains 16 values. Thefirst value is in bit 0; the last is in bit15.

The above applies only as long as thevariables remain packed. Whenever avalue is unpacked from a packedvariable, it is expanded to occupy afull word with 0s in any "unused" bits.This occurs whenever the value is

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used in an expression.

Free-Union Variants

An ordinary variant record has atag-field value that is stored as part ofthe record. Your program can use thetag-field value to determine how thevariant data is interpreted. This isuseful when the variant data is of aspecific type; the tag field serves as asafeguard against misinterpreting thevariant data.

Here, however, we are interested inpurposely interpreting the same datain more than one way. This can beaccomplished with an ordinaryvariant record: simply ignore the tagfield. If you use a free-union variant,you can eliminate the tag fieldaltogether; this saves memory andalso makes the maneuver a little moreobvious.

A free-union variant looks like anordinary variant, except that the tag-field identifier is omitted. A tag typeis still required, as are case labels. Forexample:

VAR FOXY: RECORD CASE BOOLEAN OFFALSE: (INT: INTEGER);TRUE: (BOOL: BOOLEAN)END;

Now FOXY.INT refers to a value oftype integer, and FOXY.BOOL refersto a value of type boolean. Both referto the same word of data. The labelsFALSE and TRUE, corresponding tothe tag type BOOLEAN, are chosenas a matter of convenience; you canuse any type that has enough possiblevalues to use as case labels. In theBINARY program shown in listing 2,the type THREEWAY is declaredsolely for use as a tag type for a freeunion that has three cases.

In the BITFIDDLER program, weused the INITIALIZE procedure to setup an array of integers, each integerhaving a 1 in one bit, and Os in allother bits. This was accomplished bymaking the value of each integer apower of two. In the TSTBIT func-tion and the SETBIT and CLEARBITprocedures, we used ODD to convertone of these integer values to aboolean value with a 1 in a particularbit.

In the BINARY program we use a

454 October 1981 © BYTE Publications Inc

Circle 378 on inquiry card.

free union as a more powerful meansof accessing individual bits of aboolean value —and more. This is athree-way free union that allows thesame word of data to be treated as an

integer, a boolean value, or an arrayof 16 boolean values.

Multidimensional Arrays

When you know how to access

Listing 2: The BINARY program employs free union to access the individual bits of aword. The word can also be accessed as an integer or a boolean. The distinction is madein the field of the record VALUE: the BINOUTprocedure references VALUE.BITS witha subscript to access a bit, while the main program references VALUE.INT to access theword as an integer, or VALUE.BOOL to access it as a boolean.

PROGRAM BINARY;(*This program takes an integer value from the keyboard and

displays its value as a 16-bit binary number by treating it asa packed array of 16 one-bit boolean values. Then if treatsthe value as one 16-bit boolean value, complements it, andagain displays the result as a 16-bit binary number: *)

TYPE(*A type to use as tag type in a 3-way free union: *)

THR£EWAY=(A,B,C);(*An index type for 16-element arrays: *)

BITINDEX=0..15;(*An array type of 16 booleans, each one represented as

BITARRAY=PACKED ARRAY[BITINDEX] OF BOOLEAN;(*A free union record type, which can represent an integer,or a bit array, or a boolean; same 16 bits in all cases: *)THREETYPES=RECORD CASE THREEWAY OF

A: (INT:INTEGER);B: (BITS:BITARRAY);C: (BOOL:BOOLEAN)END;

VAR(*A general index variable: *)

I: INTEGER;(*A variable of the free union type: *)

VALUE:THREETYPES;

(*A procedure which takes a parameter of free union type,treats it as a bit array, and writes the 16 bl*"S our

a bit: *)

as l's and

k)

PROCEDURE BINOUT(N'JM:THREETYPES) ;(*An index variable: *)VAR K:BITINDEX;

BEGIN(*Scan The 16 bits, most significant Eirsfi *)

FOR K:=15 DOWNTO 0 DO(*If the bit- is "true," write a 1; if ir's "false," write a 0: *)IF NUM.BITS[K] THEN WRITE('l')ELSE WR1TEC0') ;WRITELN;END;

(*Main program: *)

BEGIN(*Prompt the user for a decimal integer: *)

WRITE('Type Number: ');(*Store it as an integer value: *)

READLN(VALUE.INT);(*write it as a binary integer: *)

BINOUT(VALUE);(^Complement the value as a 16-bit boolean: *)

VALUE.BOOL:=NOT VALUE.BOOL;(*Write it as a binary integer: *)

BINOUT(VALUE);

WRITELNEND.

data in memory in this fashion, therepresentation of data valuesbecomes more interesting. Considermultidimensional arrays.

When an array has more than oneindex, the last index varies mostrapidly and the first index varies leastrapidly. For example, in a two-dimensional array the second indexcan be thought of as a "column" indexthat steps along a row, and the firstindex can be thought of as a "row" in-dex that steps from one row to thenext. The elements in a row are con-tiguous in memory. Another way tothink of this is that the declaration:

VAR TABLE: ARRAY(0..°, 0..4]OF INTEGER;

is exactly equivalent to:

VAR TABLE: ARRAY[0..9] OF ARRAY[0..4]OF INTEGER;

The ARRAY[0..4] OF INTEGER is aone-dimensional array, so itselements are contiguous. TheARRAY[0..9] OF ... is also a one-dimensional array whose elementsare arrays.

Beware of multidimensionalpacked arrays! Remember that foreach dimension of the array, the unitof storage into which values arepacked is the word, so each array thatmakes up the multidimensional arrayoccupies an integral number ofwords, with possible unused bits. Forexample, you might declare an 8-by-8packed array of boolean (1-bit)elements:

VAR X: PACKED ARRAY[0..7,0..7]OF BOOLEAN;

If you expect that X will be stored sothat all 64 elements are contiguousbits within 8 contiguous bytes, youare wrong. The declaration isequivalent to:

VAR X: PACKED ARRAY[0..7] OF PACKEDARRAY[0..7] OF BOOLEAN;

Each row of X is a packed array[0..7]of boolean, and occupies one word:16 bits, not 8. X contains eight ofthese words (16 bytes); the most-significant 8 bits of each word areunused.

October 1981 © BYTE Publications lnc 455

The Byte-Oriented Procedures

There is yet another way aroundthe strong typing of Pascal —the useof byte-oriented procedures. UCSD'sdocumentation describes FILLCHAR,MOVELEFT, MOVERIGHT, SCAN,and SIZEOF as subroutines for work-ing with packed arrays of characters.The documentation mentions that thesource and destination parameters forthese routines are not type-checked,and, in fact, you should really thinkof them as subroutines for workingwith ranges of memory bytes. If youhave the declarations:

VAR BIT: PACKED ARRAY(0..15] OFBOOLEAN;BOOL: BOOLEAN;

then you can transfer the value ofBOOL into the bit array BIT bymeans of the following statement:

MOVELEFT (BOOL, BIT, 2)

which moves 2 contiguous bytes (oneword) without checking data type.

PEEK and POKE

When you're writing in Pascal,there are very few situations where

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PEEKs and POKEs are of any use.The reason for this is that you don'tknow how the system is using mem-ory. When you access memory usinga physical address, you can easilyblunder into an area used by thesystem.

Each version of UCSD Pascal gen-erally contains its own built-in, high-level constructs for the situationswhere particular locations must beaccessed. For example, the loud-speaker on an Apple II is activated byaccessing a particular location, butApple II Pascal provides a procedurecalled NOTE that lets you generatetones on the speaker without know-ing the special location.

Suppose, however, that you have aperipheral device that wasn't an-ticipated by the designers of yourUCSD Pascal, and it needs to be con-trolled by accessing a particular loca-tion. In BASIC, you would do thiswith PEEKs or POKEs; to get thesame effect in Pascal, you must createPascal PEEKs and POKEs.

There are two tricks in PEEKingand POKEing with Pascal. The first isto declare a variable type that cor-responds to one physical memorybyte. A byte is 8 bits, and can hold avalue in the range 0 through 255. Butif you declare:

TYPE BYTE = 0..255;

it won't work correctly. The problemlies in the fundamental rule that everynonpacked scalar is represented inmemory as a word (16 bits). A vari-able of type BYTE will occupy 2bytes, with 0 in the higher-numberedbyte. To avoid this situation our"memory byte" type has to be packed:

TYPE BYTE = 0..255;

MEMBYTE = PACKED ARRAY [0..0] IOF BYTE;

Now a variable of type MEMBYTEis an 8-bit value that occupies just 1memory byte.

The second trick is that a pointervariable is represented as if it were ascalar variable: it is a 16-bit binarynumber, and its numeric value is aphysical address. Now we can declarea two-way free-union record type as

456 October 1981 © BYTE Publications Inc

Listing 3: PEEKing and POKEing. As shown in figure 3a, a two-way free-union recordtype can represent either a pointer value or an integer value. A direct reference to aphysical location can be performed with the functions shown in figure 3b.

{3a)

(3b)

1YPE BYTE = 0..255;

.-1EMBYTE = PACKED ARRAY [0..0] OF BYTE;LOCATION = RECORD CASE BOOLEAN OF

TRUE: (ADDR: INTEGER);FALSE: (PTR: "MEMBYTE)END;

PROCEDURE POKE (ADDRESS:INTEGER; VALUE.• BYTE);VAR LOC: LOCATION;f:EGIN

LOC.ADDR := ADDRESS;LOC.PTR"[0] := VALUEEND;

FUNCTION PEEK (ADDRESS:INTEGER): BYTE;VAR LOC: LOCATION;rJEGIN

LOC.ADDR := ADDRESS;

PEEK := LOC.PTR~[0]END;

shown in listing 3a.

If LOC is a variable of type LOCA-TION we can assign a physical ad-

dress, such as 32766, by writing:

LOC.ADDR

32766

At this point, LOC.PTR t [0] is adirect reference to the contents ofbyte location 32766. We can nowdeclare a POKE procedure and aPEEK function (see listing 3b).

As in BASIC, there is one wrinkleto using PEEK and POKE. Because ofthe two's-complement notation fornegative integers, the largest possiblepositive integer value is 32767, or215 —1. In order to represent a phy-sical address greater than this, youmust use a negative integer to get thedesired binary number (see table 1).

Going Further

You now have enough informationto make experiments that will tell youeven more about the inside workingsof your system, and you may evendiscover more useful programmingtricks. Remember the warning,though: tricky programming maywork once, but you can receive anasty surprise when you change yourprogram, switch systems, or try touse an updated version of UCSDPascal. ■

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October 1981 © BYTE Publications Ire 457

Apple Analog-to-DigitalConversion in 27 Microseconds

Michael A Seeds, Associate Professor of Astronomy

and Harold F Levison

Joseph R Grundy Observatory

Franklin and Marshall College

POB 3003

Lancaster PA 17604

We began designing a computer-controlled data-acquisition system for the Franklin and Marshall Collegeobservatory, when suddenly we realized that we wouldhave to build our own A/D (analog-to-digital) circuitboard. Most commercially available A/D boards aredesigned for the S-100 bus or computer buses other thanthe Apple II. The only board we found specificallydesigned for the Apple was both expensive ($395) andvery slow (400 milliseconds). At this time, variousmanufacturers are announcing new A/D boards for theApple, but these, too, are expensive, and at least one ofthese has only 8-bit resolution. Our data system required10-bit accuracy and high-speed performance. The circuitwe designed to meet these requirements costs less than$100. (See table 1.)

Circuit Description

The Apple A/D circuit can be divided into four sec-tions. The input section consists of two 741-type opera-tional amplifiers and an AD582 sample/hold amplifier.The op amps accept a signal between 0 and 10 V and pro-vide a zero offset adjustment. The AD582 device followsthe input voltage until it receives a control signal in-dicating that an analog-to-digital conversion is to takeplace. It then samples the input voltage and holds its out-put to that voltage for the duration of the conversion.Thus, the AD582 provides a constant voltage (adjustablewith gain control) for the conversion process, preventinga rapidly changing input signal from destroying the ac-curacy of the conversion. The heart of the circuit's secondsection is an AD571 analog-to-digital converter device,which performs the actual conversion of voltage levels todigital data. (Both the AD571 and the AD582 are

manufactured by Analog Devices, POB 280, NorwoodMA 02062.) Section three contains the three-state-outputlatch devices, a 74125 and a 74LS244. On command fromthe microprocessor, these connect the output of theAD571 converter to the system data bus. Finally, thefourth section contains a 74LS138 demultiplexer thatdecodes the address bus input, controlling the actualoperation of the A/D circuit through a 7400 quad two-input NAND device and a 7404 hex-inverter package.

The 7400 NAND gates play a critical role in the opera-tion of this circuit. Address signals appear on the Apple IIsystem bus for less than 1 microsecond, but the AD571converter requires a pulse no shorter than 2 microsecondsto initiate a conversion. Expanding the pulse width of thiscontrol signal with a flip-flop constructed from a 7400device satisfied this requirement.

Referring to figure 1, a conversion begins when the

1 Apple protoboard

$24.00

2 741 op amps

0.80

1 AD582 sample-and-hold amplifier

14.05

1 AD571 analog-to-digital converter

23.00

1 7404 hex inverter

0.25

1 7400 quad dual-input NAND gates

0.22

1 74LS138 demultiplexer

0.99

1 74LS125tri-state latch

0.89

1 74LS244 tri-state latch

2.95

1 10 K 10-turn potentiometer

10.65

1 10 K 1-turn potentiometer

3.30

Total

$81.10

Table 1: List of components necessary to bu

ild the

A/D con-

verier shown in figure 1, The prices given by the at

tthor may

not be representative of current component

prices

458 October 1981 © BYTE Publications Inc

processor writes a datum to hexadecimal memory loca-tion COAO (assuming the A/D circuit card is plugged intoslot two of an Apple). This sends the card select line(DS) into a low state, enabling the 74LS138demultiplexer to decode the zero value present on thethree least-significant lines of the address bus, A0 to A2.Output zero of the 74LS138 (the START line in figurej.)goes low, which, combined with the R/W(READ/WRITE) line already in a low state from the pro-cessor write, sets the flip-flop and forces the B + C linehigh. This tells the AD571 to prepare for a conversion.When it is ready, the converter sends the DR line high,resetting the flip-flop, sending B + C low and initiatingthe conversion. Thus the addition of the flip-flop permitsthe AD571 to start a conversion only when it is ready,assuring that the sub-microsecond pulses on the addressbus will start a conversion.

The DR line remains high while the AD582 chip ismaking a conversion—about 25 microseconds. WhenDR goes low, the conversion is complete and the data is

ready. This DR line could be used to provide aninterrupt, but we chose to bring it to the data bus througha three-state latch and allow the computer to test DRrepeatedly until it goes low. Because the circuit operatesso fast, machine-language programs test DR only twicebefore it goes low, and BASIC programs do not run fastenough to catch DR while it is still high. Thus, testingDR with a software loop wastes very little time.

Operation

When the A/D card is signaled to begin a conversion,

Number

Type

+ 5

GND

-12 V

+ 12 V

IC1

LM741

4

7

IC2

LM741

4

7

IC3

AD582

5

10

IC4

AD571

10

12

IC5

7404

14

7

IC6

7400

14

7

IC7

74LS138

16

8

IC8

74125

14

7

IC9

74LS244

20

10

ADDRESS BUS

DATA BUS

Figure 1: Schematic of the A/D converter built on an Apple II plug-in prototyping card using ordinary soldering techniques. Twospecial components from Analog Devices comprise the heart of this fast and inexpensive circuit. This circuit can be easily adapted toother computer systems.

October 1981 © BYTE Publications be 459

the input circuit samples the analog voltage to be con-verted and holds it constant during the conversion. TheA/D device makes the conversion, and once the 10 bits ofdata are ready, the board signals the computer by pullingDR low. The computer may then read the 8 MSBs(most-significant bits) in 1 byte and the 2 LSBs (least-significant bits) in another. If 8-bit resolution is sufficient,the 2 LSBs can be ignored.

Operation from a 6502 machine-language program isaccomplished as follows. (Again, we assume the card is inslot 2.) The execution of STA $C0A0 (write the contentsof the accumulator to hexadecimal location C0A0) beginsa conversion. The computer then checks to see if the datais ready by LDA $C0A3 (read from C0A3). As soon as

Command

BeginConversionGet DR8 MSBs2 LSBs

6502 Machine Language BASIC

STA $C0A0LDA SC0A3LDA $C0A1LDA $C0A2

POKE 49312,0PEEK (49315)*PEEK (49313)PEEK (49314)

"Unnecessary for BASIC programs

Table 2: Control and status commands for the A/D con-verter. Note that 2 bytes must be read to get 10-bit resolu-tion. The memory locations specified and the machine-language and BASIC instructions are from the original in-stallation on an Apple II.

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the eighth bit in this cell goes to 0, the data is ready andthe computer can read the 8 MSBs with LDA $C0A1 andthe 2 LSBs with a LDA $C0A2.

On our board, we found that the fifth bit of locationC0A2 fluctuated between 0 and 1. When the computer isreading the contents of location C0A2, the 6 LSBs areundefined. The computer should recognize these as 0s,but that may not always be the case because of variationsin the components. The solution is to mask the byte readfrom location C0A2 with an AND #$C0 (logical ANDwith the hexadecimal value CO). This ensures that the 6low-order bits will be 0. Similarly, the contents of loca-tion C0A3 can be masked by an AND #$80 to be sure thatonly the eighth bit can be a 1.

The A/D board can also be operated from BASIC pro-grams by using a POKE 49312,0 to begin the conversionand PEEK (49313) and PEEK (49314) to read the high- andlow-order parts of the data. You must beware, however,of undefined bits in the low-order word. These can causeconfusion and limit the board to 8-bit resolution when itis used from a BASIC program. These hexadecimal andBASIC commands are summarized in table 2.

The best arrangement for using the card from a BASICprogram uses a short machine-language program to han-dle the actual conversion and masking. The programshown in listing 1 will assure that no undefined bits con-fuse the data. The program is relocatable and communi-cates with other programs via zero page locations FE andFF. The AND instructions mask off undefined bits.

If this subroutine is called from a BASIC program, thetwo words of data can be combined into a single numberby:

X = PEEK (254)*4 + PEEK (255)/64

Division by 64 is necessary because the 2 LSBs occupy thetwo highest-order bits of the word in hexadecimal C0A2.

Speed

Analog Devices lists the speed of its AD571 chip as25 jts, typical. Tests of our A/D board indicate that thetime from the beginning of a conversion until the data isready is about 27 fis. The time needed to read the 10 bitsof data and store them in memory locations is about

Listing 1: The 6502 machine-language routine called fromBASIC that assures that no undefined bits will confuse the dataread from the A/D circuit.

8D A0 CO Begin

STA $C0A0

Start a conversion

ADA3 CO Test

LDA $C0A3

Get DR

29 80

AND #$80

Mask off undefined bits

D0F9

BNE Test

Test DR

ADA1CO

LDA $C0A1

Get 8 bits of data

85 FE

STAZ $FE

Store in zero page

ADA2C0

LDA $C0A2

Get 2 bits of data

29 CO

AND #$C0

Mask off undefined bits

85 FF

STAZ $FF

Store in zero page

60

FITS

460 October 1981 © BYTE Publications Inc

Circle 416 on inquiry card.

Figure 2: A 1 kHz signal sampled at 8-bit resolution thirty-onetimes per cycle. Note that since the circuit described does notaccept negative-input signals, the lower half of this signal hasbeen clipped off.

24 /xs minimum, so the card can sample the input approx-imately every 50 lis. The overhead for data handlingcould be cut to 9 lis by using only the 8 MSBs.

Our operating system must be able to sample the inputsignal at a minimum of 1000 times per second at the direc-tion of 1-millisecond interrupts from the clock. The speedof our A/D board gives us plenty of time to read thedata, modify it as necessary, calculate the next empty ad-dress of memory (skipping over page 1 of the high-resolu-

tion display), and store the data. The system then waitsfor tfie next 1-millisecond interrupt before beginning thenext conversion.

Figure 2 illustrates the speed of the card as used in oursystem. The input signal is a 1 kHz sine wave. The A/Dconverter accepts only positive voltages, so the negativeportion of the sine wave is clipped. With the data-acqui-sition system free-running, independent of clock inter-rupts, and accepting only 8-bit resolution, the computercould sample the input signal thirty-one times per cycle.

Setup

This circuit has two controls that must be adjustedbefore the converter is used in any specific application.For example, the prototype (developed under a grantfrom the National Science Foundation) is used at anobservatory to detect the light of a particular star as itdisappears behind the moon. To compensate for exces-sive moonlight that can interfere with the measurements,the system is focused on a moonlit portion of the sky nearthe target star, and the zero offset control (see theschematic in figure 1) is adjusted until the converter givesa zero reading. The system is then focused on the targetstar and the gain control is adjusted for a full-scalereading (maximum output corresponds to maximumbrightness). This ability to compensate for a variety of in-put conditions makes the A/D system adaptable to awide assortment of applications. ■

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October 1981 © BYTE Publications Inc 461

A FORTH-Like ThreadedLanguage, Part 1

Valo G Motalygo

1091 Tanland Dr #204

Palo Alto CA 94303

[Editor's Note: Alan Taylor of Computerworld oncecalled the FORTH programming language "not so much alanguage itself as a hotbed for growing other languages."The PS language described in this article is a newlanguage with its roots in the FORTH hotbed and theconcept of subroutine-threaded code (see "Varieties ofThreaded Code for Language Implementation" by TerryRitter and Gregory Walker in the September and October1980 issues of BYTE). This is an advanced theoretical ar-ticle that draws heavily on a working knowledge ofFORTH. For further information, see "What Is FORTH?A Tutorial Introduction" by ]ohn S James, and the otherFORTH articles, in the August 1980 BYTE devoted to thelanguage.... GW]

The main purpose of a programming system is tofacilitate the user's communication with the computer.

I believe that operating systems or programminglanguages accepting something like conventional text areclose to being ideal where the user-computer interface isconcerned. All the other advantages or disadvantages ofany particular system are "problem-oriented." In otherwords, what is convenient for one user might be unac-ceptable for another. Let us consider programmingsystems that are supposed to be useful for all potentialusers, beginning with the simplest system of thiskind—assembly language.

There are many flaws with assemblers: assembly-language programs are not portable, they are difficult towrite and debug, the user must have detailed knowledgeof the computer hardware, and so on. However inconve-nient it is, an assembly language is still a general-purposeprogramming system, much as the computer is a general-purpose data-processing device.

On the other hand, designers of high-level languageshave to pay for obliterating low-level potential by sup-

About the Author

Valo G Motalygo is on the staff of Friends Amis Inc. involved withthe Quasar hand-held computer, and is currently working on an im-plementation of PS.

porting painful procedures of introducing assemblersubroutines into a high-level program.

Thus, the problem with low-level languages is thatthey are not convenient to use; the problem with high-level languages is that they cannot be considered general-purpose programming systems because of their lack oflow-level capabilities and their tendency to force pro-gramming structures that might not be optimal for theproblem at hand.

The multilevel approach to

programming has enriched FORTH

with many interesting features.

FORTH is a good example of a multilevel system wherethis conflict is partially resolved. The multilevel ap-proach to programming has enriched FORTH with manyinteresting features (see the article "What Is FORTH7 ATutorial Introduction" by John S James on page 100 ofthe August 1980 BYTE).

The principal idea of FORTH is to use a set of general-purpose low-level subroutines for encoding new ones,which can be further used for introducing more sophisti-cated programs. To implement this simple idea, FORTHprovides the user with a set of tools, briefly describedbelow.

FORTH maintains a dictionary where every subroutineis stored with its name and either an object code or a se-quence of pointers to other subroutines in the dictionary.A dictionary entry is called a word and the address of aword in the dictionary is called a word pointer. In someFORTH systems, the sequence of the word pointers ispreceded by a short piece of object code that executes (or"chains") the words being pointed to. A dictionary entryalso contains the address of the previous word tofacilitate searching for a word in the dictionary.

The low-level words in FORTH are stack operationslike DUP (duplicate the number on the top of the stack),DROP , SWAP , -I- (add the two numbers on the stack),AND , OR , NOT , and @ (pronounced fetch and

462 October 1981 © BYTE Publications Inc

meaning replace an address on the top of the stack withits contents). All the stack operations are described morethoroughly in the "FORTH Glossary" (August 1980BYTE, page 186).

The stack operations can be considered an expandedinstruction set. Data can be introduced and accessed withthe help of words like VARIABLE , CONSTANT ,{ ." } (pronounced dot-quote and meaning compile andtype an ASCII string), &X (push ASCII code of X ontothe parameter stack), etc. [Remember that BYTE usesbraces to delineate certain FORTH words and phrases;see the PS Syntax text box for more details....GW]

It is easy to write programs inFORTH, but it is a pain in the neckto program in FORTH's assembler.

A programmer can define new words through the low-level ones or through the previously defined words, usingsuch auxiliary tools as the control structures{ IF...ELSE...ENDIF }, { BEGIN.. .AGAIN },{ BEGIN...UNTIL }, { DO...LOOP }, etc.

FORTH also has the capability of defining new wordsin the assembly language of the computer FORTH is run-ning on. These words can be executed or used in high-level definitions as other words are used. Unfortunately,FORTH's assembler does not allow many of the facilitiesused while defining high-level words. For example, stackmanipulations (DUP , DROP , SWAP , etc) are notsupported, and no FORTH words can be mixed with theassembler code.

It is easy to write programs in FORTH itself, but it is apain in the neck to program in FORTH's assembler. Thisis because you must abandon the capabilities of the highlevel and descend to an entirely new language—one thatsignificantly differs from conventional assemblers, aswell as from FORTH itself.

The reason why FORTH's assembler is not an organicpart of FORTH is that these languages have different out-puts: executable object code (for the FORTH assembler),and word pointers that must be chained to get executed(for FORTH itself). One way to resolve this conflict is aFORTH-like system that generates only object codewithout generating the word pointers. This two-part arti-cle describes the structure of a simple system of this kind,called PS (for Programming System).

Introduction to PS

Let us consider a programming system that is able toaccept the following text:

ORIGIN xxxx nn nnnn nn nnnn ...RUN yyyy

The words nn and nnnn represent 8- and 16-bit hexa-decimal numbers. When a 16-bit number is compiled, the

compilation address (also called code pointer) is in-cremented by 2. When an 8-bit number is compiled, thecompilation address is incremented by 1.

ORIGIN is a special word that executes at compilationtime. It takes the next word (xxxx) from the text, convertsit to a 16-bit number, and sets the compilation addressequal to this number.

RUN is another special word; it takes the next word(yyyy), converts it to a 16-bit number, and calls asubroutine at the address given by this number.

This primitive system has only one significant flaw: itis not very convenient to write programs directly in ob-ject code. But let us disregard the lack of conveniencemomentarily and think of an initial PS implementation.The compilation process operates as follows:

1. Read the next word from the text.

2. If it is a number, push it into the code and go to 1.

3. If it is a special word, execute it and go to 1.

The system will be more convenient with more specialwords defined. One such example is LABEL (which isused as { LABEL <name> } ). It stores the word<name> together with the current compilation addressinto the dictionary.

We are considering a FORTH-like system that has adictionary with all the necessary information about thespecial words. That is, now that the word LABEL is in-troduced, the PS dictionary contains three words:ORIGIN , RUN , and LABEL . The word LABEL allowsthe use of names instead of numbers in some situations.

Our system must be able to distinguish among severalkinds of words: special words like ORIGIN or LABEL ;numbers; and labels, which are replaced with the number

PS Syntax

PS, like FORTH, uses punctuation in some of its words,which makes representing them in text a difficult problem.To decrease the chance of confusion while trying not to clut-ter text unnecessarily, we will sparingly use braces, {}, toisolate the character string within as a PS word or phrase.Braces will be used only under the following situations:

• when the material being quoted is a phrase of PS words (eg:{ 26 LOAD }or{35+ } )

• with the PS words { , } (comma), { : } (colon), { ; }(semicolon), { ! } (exclamation point), { ' } (single quotemark), { " } (double quote mark), { I } (left bracket), and{ 1 } (right bracket)

• with any word using punctuation marks (eg: { ." })

All other PS words will be set apart by a space on eitherside of the word. So, in this article, braces will always signala PS word or phrase. The braces are not part of the word orphrase, and PS words will never use braces within the bodyof a figure or listing... .GW

October 1981 © BYTE Publications Inc 463

assigned to the label. We will use the phrase "value of theword" or the shorthand notation V to denote the currentcompilation address of the word, as stored in the dic-tionary with the word.The new PS compilation process is:

1. Read the next word.

2. If it is a number, push it into the code and go to 1.

3. If it is a special word, execute it and go to 1.

4. If it is a label, push V into the code and go to 1.

The next step is to introduce undefined labels to allowforward references. If PS hits a name that is not in thedictionary, it assumes that the name's value will be de-fined later by LABEL . Meanwhile, PS makes a fake en-try for this name with the value of the word, V, tem-porarily set to the current compilation address, also com-piling 0000 into the code area instead of some real value(see figure la).

If PS hits an undefined label for the second time, itcompiles the address of the fake entry (ie: the address ofthe previous reference to the undefined label) into thecode area and sets V to the current code pointerdecremented by 2, linking locations where the undefinedlabel is used (see figure lb).

When the LABEL statement is encountered, it mustdetermine whether the word being defined has been usedbefore. If it has, LABEL replaces the linked dummypointers pointed to by the fake V with the value of thecurrent code pointer. After this is done, V is also set tothe value of the current code pointer, resolving the for-ward reference and turning the fake entry into the realone (see figure lc).

It is more convenient to link and

resolve forward references if the

dictionary is separated from the

code.

In general, PS links forward references to each otherand to the value of the undefined word, with LABELresolving forward references by storing the current codepointer in the locations linked by PS. If the word NEW iscompiled at the address cccc, the resolved references ap-pear as in figure lc. The technique used here is essentiallyidentical to that used by many one-pass assemblers andcompilers.

It is more convenient to link and resolve forwardreferences if the dictionary is separated from the code.This is because when PS hits a new word, a fake entry forthis word is created before the space required to hold thecode of the undefined word is known. This is very dif-ferent from FORTH, which requires that every word bedefined before it is used.

A More Sophisticated PS

This system has to distinguish between special words,

numbers, defined labels, and undefined labels. Let usassume that the type of the word (T) is stored in the dic-tionary with the name and its value. The new version ofPS is then as follows:

1. Read the next word.

2. If it is a number, push it into the code and go to 1.

3. If it is an old word, check its type:If T = special, execute and go to 1.

If T = defined, push the value of the word (V) into thecode area and go to 1.

(la)

ADDRESS CODE

1111

0000

(lb)

ADDRESS CODE

1111

2222

0000

2222

(lc)

ADDRESS CODE

1111

2222

3333

CCCC

CCCC

DICTIONARY

WORD NAME'NEWTYPE'UNDEFINEDVALUE'1111

DICTIONARY

WORD NAME'NEWTYPE'UNDEFINEDVALUE'3333

DICTIONARY

WORD NAME'NEW

TYPE'DEFINED

VALUE'CCCC

Figure 1: Handling of forward references in PS. Figure la showswhat happens when the word NEW is first encountered as anundefined word. Figure lb shows several occurrences of theword NEW linked together. When the word NEW is finallydefined (by use of the word LABEL), the address of NEW is putinto its dictionary listing and into the previous references to it.

464 October 1981 © BYTE Publications Inc

If T = undefined, link the reference as described aboveand go to 1.4. If it is a new word (ie: not encountered before):Make a new entry (that is, add this word to the dic-tionary), set the type to "undefined," set V to the codepointer, push 0000 into the code, and go to 1.

Let us introduce another special word "—> " (pro-nounced "jump to" and used as { — > <name> } ).This word compiles a jump to the address correspondingto the word <name> .

Now that labels can be compiled by the special word— > , we can interpret the nonspecial words as namesof subroutines that are to be compiled as JSR V, whereJSR is a "jump to subroutine" instruction and V is the ad-dress of the subroutine. (We assume a 6502-based systemhere. You would substitute the appropriate machine-language instruction for systems based on other micro-processors.) So the principal idea of FORTH (ie: buildingprograms from previously defined subroutines) is fullyimplemented now that the words LABEL and — > havebeen introduced.

Our system will be more useful if it can execute thecompiled words. To switch PS from compilation to ex-ecute mode, we can introduce two special words: { [ }(left bracket), which enables the execute mode, and { ] }(right bracket), which enables the compile mode.

PS with the execute and compile modes looks asfollows:

1. Read the next word.

2. If it is a number (this is discussed in more detailbelow).

3. If it is an old word in compile mode, check its type:If T = defined, compile JSR V and go to 1.

If T = undefined, compile JSR (link), link it as de-scribed above, and go to 1.If T = special, execute it and go to 1.

4. If it is an old word in execute mode, check its type:If T = defined, execute it and go to 1.

If T = undefined, print an error message, go to 1.If T = special, execute it and go to 1.

5. If it is a new word in compile mode:

Make an entry, set the type to "undefined," compileJSR 0000, go to 1.

6. If it is a new word in execute mode, print an errormessage, go to 1.

An inquisitive reader now has at least two questions:what about arithmetic operations with labels, and whatshould happen to numbers?

The problem with numbers is that in one mode wewant them to be compiled into the code; in another modewe want them to be pushed onto the parameter stack.The problem with arithmetic expressions is that we wantaddresses to be computed at compilation time.

The solution for both problems is to consider the com-piled code as the parameter stack. That is, at run time wecan push parameters into the free memory that follows

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October 1981 © BYTE Publications Inc 465

the compiled code. To keep track of the stack entries, wecan increment (or decrement) the same code pointer usedat compilation time. If the stack is used correctly, thecode is not destroyed. Or we can check before everystack operation to make sure that the compiled code isnever destroyed.

We will say that a number is pushed onto theparameter stack or pushed into the code or compiledwhenever the number is stored in the location pointed toby the current code pointer. Then, in execute mode,numbers can be pushed into the code and added, multi-plied, divided, etc, by the words + , — , / , and * . Incompile mode, a number can be compiled with apreceding code that pushes the number onto theparameter stack at run time. This is done by the wordsPSHN (push number) and NUMBER, which will be dis-cussed in part 2.

The use of the free space after the compiled code as aparameter stack adds much to the simplicity and flexibili-ty of PS.

Low-Level Programming in PS

Let us assume that we have implemented PS with allthe special words and stack operations described earlier.Let us also suppose that all the necessary subroutines arewritten in conventional assembly language, like that ofthe 6502 microprocessor, and are represented in the PSdictionary (ie: their names and addresses are stored in thePS dictionary with the assignment of the appropriatetypes).

Later, when speaking of the computer or the assem-bler, we mean the computer PS is running on and itsassembler. We will also assume that the computer has astack pointer for maintaining the computer stack and thatthe JSR instruction leaves the return address on the com-puter stack, just as it is done in the 6502. If there is nohardware stack, software can be written to simulate one.

Now, we will reexamine the simplest case—when PS isin execute mode with only numbers being compiled. If wewant to compile an address or a 16-bit signed integer, wesimply type in the number with either a leading zero (forpositive numbers) or a minus sign (for negativenumbers). Examples are Ox, Oxx, Oxxx, Oxxxx, —x, —xx,—xxx, and — xxxx. (Because PS accepts undefinedwords, it needs a way to distinguish numbers.) If we wantto compile an instruction code or an 8-bit number, wecan say § xx, where § is a special word that converts xx toan 8-bit number and pushes it into the code.

Our system will be more convenient if we introducetwo more auxiliary words: CONST and BCONST. Theseare used as { CONST <name> nnnn } and{ BCONST <name> § nn }, where nnnn and nnrepresent 16- and 8-bit numbers, respectively.

CONST (constant) makes a new entry in the PS dic-tionary for the <name> and compiles code that willpush nnnn into the code at run time.

BCONST (byte constant) acts similarly, pushing an8-bit number into the code at run time. The special word

§ is used with BCONST to emphasize the difference be-tween CONST and BCONST. BCONST is used basicallyto compile 1 byte of object code. Thus, we can define theinstruction set of the computer as a set of byte constantswith whatever mnemonics we like. For example, on the6502:

BCONST JSR # 20BCONST JMP # 4CBCONST RTS § 60

allow use of the mnemonics for the instructions "jump tosubroutine," "jump via direct addressing," and "returnfrom subroutine," instead of hexadecimal numbers 20,4C, and 60. Also, naming the Boolean constants:

CONST TRUE 01CONST FALSE 0

makes a program more readable.

To handle variables, the word VAR is used as{ VAR <name> nnnn }. When VAR is executed, itcreates a new entry for the word <name> and compilesobject code that pushes the address of the memory loca-tion following this code onto the parameter stack at runtime. The number nnnn is compiled by the text inter-preter and is used to initialize the contents of the variable.One-byte variables can be defined as{ VAR <name> § nn }.

A special word " (quote) is used as { " aaaaaaa" },where aaaaaaa is a string of ASCII characters. The firstquote compiles the following string preceded by its bytecount. The second quote terminates the string. The spaceafter the first quote is required so the text interpreter canidentify quote as a word in its own right.

Strings can be defined in PS as follows:{ VAR < name > " < some text > " }. When the word< name > is executed, the address of the string is pushedonto the parameter stack.

Arrays can be defined with the help of a special wordcalled ARRAY, used as { ARRAY <name> nnnn }.When the word < name > executes, it pushes the addressof the nnnn bytes, allocated for the array, onto the stack.

This completes part 1 of this article. In part 2, we willlook at examples of low-level and high-level code in PS,and add a PS dictionary that includes some of the moretechnical details of the language.■

Acknowledgments

/ want to thank the programmers and management of Friends Amislnc for their help and support in carrying out this work, especially JimHouha and Rick Creicar, who nearly rewrote the manuscript: VictorEliashberg of VARIAN Associates, who helped me realize thesignificance of hardware-software relationships; Anya Kroth of theUniversity of California at Santa Cruz for her sharp remarks and kindcriticism; Dave Boulton, FORTH consultant and member of theeditorial review board of the FORTH Interest Group, and Bill Wilkin-son of Optimized Systems Software, who made this work moreunderstandable. Samuel Feldman of Hewlett-Packard made this workmore understandable for the author himself.

466 October 1981 © BYTE Publications lnc

System Notes

Recursive Proceduresfor the 6502 Microprocessor

Dr Phillip W Dennis, 15314 Vi Larch Ave, Lawndale CA 90260

In recursive applications, the limited stack size of MOSTechnology's 6502 8-bit microprocessor is a drawback.Due to the 6502's stack being restricted to one page (256bytes starting at location 256, or page one of memory),subroutine calls are limited to a maximum of 128 levels. Ifthe stack is used for temporary storage (or the recursiveprocedure calls other subroutines), then the depth ofrecursion possible is even less. Conversely, the Motorola6800 microprocessor has a 16-bit stack pointer and theability to locate the stack anywhere in memory.

Recently, I was confronted with this restriction duringa conversion of S Tucker Taft's M6800 LISP interpreterto the 6502. (See reference 1.)

The stack-management routines in this "System Note"are based upon the 6800 routines in Mr Taft's article. The

6502 STACK PAGE

STACKPOINTER

SP3

major difference is that the 6800 can relocate its stackrapidly via the TXS instruction, while the 6502 must per-form a slower 256-byte move of the stack page to mainmemory.

The technique for carrying out 6502 recursive pro-cedures requires the procedure to detect two conditions—the overflow of the stack and the underflow of thestack. To detect overflow, each call to the recursive pro-cedure must be accompanied by a check of the stackpointer. If the recursive procedure requires a certainnumber of bytes of stack storage per call (STKMIN), thena call to the procedure when the stack pointer is withinSTKMIN bytes of the stack top results in a stack over-flow. At this point, code is executed to move the currentstack to main memory, pointers are saved to point to the

STACK PAGE 3

MAIN MEMORYSTACK PAGE 2

STACK PAGE 1

SP2

SP1

TOP

BOTTOM

STKRES - 1

Figure 1: Typical stack configuration during execution of a recursive procedure that uses the stack-management routines. When thenormal 256-byte stack page (page one of the 6502 memory space) is full, the contents are moved to another part of memory, freeingan additional 256 bytes of stack space. If the stack pointer returns to the bottom of the current stack page, the stack-restore routine(STKRES) moves the previous stack page (if any) back from main memory to page one, where it is treated as the current stack. Thevalue of the stack pointer at the time that page was moved to main memory (stored as SPl, SP2, etc) is also restored.

October 1981 © BYTE Publications Ire 467

System Notes.

area where the stack was moved, and the stack pointer isreinitialized to the bottom of page one.

Detection of a stack underflow normally occurs in onlyone instance—when the recursive procedure is returningto a level with a return address located in the portion ofthe stack that was moved to main memory. It is the re-sponsibility of the underflow-detection routine to restorethe stack from main memory. One way to detect the un-derflow condition is to check the stack pointer prior toevery return from the recursive procedure, and if an un-derflow is detected, branch to a stack-restoring routine.This method is slow, tedious to code, and wasteful ofprecious memory.

Fortunately, there's a more elegant way to detect un-derflow. This is done by initializing the bytes at the bot-

tom of the 6502 stack to point to a stack-restore routine.Thus, a return executed at the moment of underflow ac-tually returns to the stack-restore routine, whose func-tion is to restore the stack to the state prior to its move tomain memory. This state can be represented by the valueof the stack pointer at the moment it was moved to mainmemory and a pointer to the previously moved stackpage. Figure 1 shows the memory configuration at atypical moment of execution.

Note that the implementation presented here assumes amemory-management scheme in which the stack pages inmain memory are allocated from the low end of memoryin increasing order, while all other data is allocated start-ing at the high end of memory in decreasing order. Thepointers to these boundaries (figure 2) are stored at sym-

Listing 1: Assembly-language stack-management routines for recursive 6502 procedures: STKINIT initializes the special stack;STKCHK checks for stack overflow; STKRES, executed at stack underflow, restores the previous stack to page one of the 6502memory.

10101Q20103010401 050I 060107O1 08010901100111011201 1 301110115011601 1701180119012001210122012301240125012601270128012901300131013201330134013501360137013801390140014101420143014401450146014701 480149015001510152015301540155015601570158015901600

* / / /till*,'//*.'//*///tilltillt/ //*///*///«///tilltilltilltilltilltilltill*///tilltilltlllll

illllilll/llllII1/11llllI

STACK MANAGEMENTPACKAGE FOR RECURSIVE6502 PROCEDURES.

BY P.W. DENNISSYMBOLIC LABELS -

1T0P) := POINTER TO

DATA AT HI MEM

(NEXT):= POINTER TOPREV STACKPAGE.

LUMEM := INITIAL LDC.FOR 1 STSTACK MOVE.

MEMFUL:= MEMORY FULLERROR EXIT

STKMIN:= STACK SPACEREQUIRED BYTHE RECURSIVEPROCEDURE

/ 11111111111111 / 111111 / /

///III

IIIIII11/IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII /1IIIIII111III

*/1111111111111111111111111117I11till III

Dill STACK INITIALIZATION ///

till III

till PLACE IN LINE AS FIRST ///

*/// INSTRUCTIONS OF ///*/// PROGRAM ///

*/// ///

»/1111111111111711111111111II1111t

LDX #LOMEM ; INIT POINTERSTX NEXT ; TO LOW ENDLDX /LOMEM ; OF MEMORY FORSTX NEXT+1 ; 1 ST STACK MOVE*

LDX /STKRES-1 ; INIT STACK "BOTTOM"STX »1FC ; TO POINT TOLDX SSTKRES-1 ; STACK RESTORESTX tlFB ; ROUTINELDX #*FA ; AND INITTXS ; STACK POINTER

»

tl 11111111II lllll I lllll 111IIII IIItill III

till STACK CHECK ROUTINE ///

till ///

till JSR STKCHK AS 1 ST ///

*/// INSTRUCTION OF A ///*/// RECURSIVE PROCEDURE. ///*/// ///

t/ / / / /1 / / / 11 / /1 / I /I / / / / / / // / /////tSTKCHK .ED *

1610

*

1620

TSX

CHECK STACK FOR OVERFLOW

1630

CPX

#STKMIN ;

ENOUGH SPACE ?

1640

BCC

STKSAV ;

NO, GO SAVE STACK

1650

RTS

YES, JUST RETURN

1660

*

1670

STKSAV

.EQ

*

1680

*

1690

LDY

NEXT ;

SAVE LINK

1700

STY

*1FE ;

TO

1710

LDY

NEXT+1 j

STACK PASE IN

1720

STY

tlFF J

MAIN MEMORY.

1730

*

1740

I NY

;

SKIP UP TO NEXT PAGE

1750

CPY

T0P+1 ;

CHECK FOR COLLISION WITH

1760

t

;

STUFF AT HIGH END OF MEMORY

1770

*

1780

BCC

STKSV1 ;

NO COLLISION, GO MOVE STACK.

1 790

J MP

MEMFUL ;

GO TELL BAD NEWS.

1800

*

1810

STKSV1

.EQ

*

1820

*

1830

STY

NEXT+1 :

SAVE POINTER

1840

INX

;

SKIP OVER CURRENT

1850

INX

RETURN ADDRESS

I860

STX

*1FD ;

AND SAVE CURRENT STACK POINTER.

1870

«

1 880

LDY

#0 ;

INDEX FOR 256 BYTE MOVE

1890

STKSV2

LDA

»100,Y

1900

STA

(NEXT),Y

1910

DEY

1920

BNE

STKSV2

1 930

*

1940

PLA

;

NOW SET UP RETURN TO CALLER

1950

STA

*1F9

1960

PLA

1970

STA

S1FA

1 980

LDX

tttFB ;

RESET STACK POINTER TO POINT

1990

TXS

!

TO BOTTOM OF STAC! !*FA) AFTER

2000

RTS

AND RETURN.

2010

*

tl II1111111111111III /111111II1111

till III

till STACK RESTORE ROUTINE ///

till III

tl 11II111111 111111111111111111111

O80

STt RES

.EQ

*

090

*

100

LDY

tto

INDEX FOR 256

1 IC

ST!

RSI

LDA

(NEXT),Y

120

STA

tioo,v

13C

DEY

140

BNE

STI RSI

15C

*

160

LDA

tlFE

RESTORE LIN)

1 ■".

STA

NEXT

TO NEXT

180

LDA

tlFF

STACK PAGE

190

*

STA

NEXT+1

IN MAIN MEMORY

210

LDX

*1FD

RESTORE OLD

T?°.

TXSRTS

STACT POINTERAND RETURN.

468 October 1981 © BYTE Publications Inc

bolic locations NEXT and TOP, respectively.

Also, this implementation does not assume that stackpages in main memory are page aligned (ie: the stack areastarts on a page boundary). If they were page aligned, thelow byte of NEXT would always be 0. This would free anextra byte of stack space and simplify the STKCHK and

STKRES routines by deleting the code that refers to thelow byte of NEXT.

Finally, note that if an application requires several re-cursive procedures, then STKMIN should be marked as:

STKMIN = max {STKMIN: STKMIN„}

DATA

FREESPACE

STACK PAGES

IN

MAIN MEMORY

PROGRAM,VARIABLES,SYSTEM USE,ETC.

STACK

$200$1000

Figure 2: This stack-management technique, developed on theApple II, assumes system-memory management as shown here.

HIMEM

■TOP

•NEXT

■LOMEM

where STKMIN, is the stack storage required by the ithrecursive procedure. Alternatively, to avoid wastingtime, program the STKCHK routine to check a table ofSTKMINs indexed by the Y register. The calling pro-cedure identifies itself as the caller by setting the Yregister to point to the appropriate table entry. Line 1630in listing 1 would then be replaced by:

TXA

CMP MINTAB,Y

The stack-management routines written on an Apple IIusing the S-C II assembler are given in listing 1. (The S-Cassembler is available from S-C Software, POB 5537,Richardson TX 75080.)■

Reference

1. Taft, S Tucker. "The Design of an M6800 LISP Interpreter."August 1979 BYTE, pages 132-152. Reprinted with complete 6800assembly-language code for LISP interpreter as Document 112 inthe BYTE Nybbles Library, now out of print.

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What's New?

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TRS-80 ColorComputer ROMs

Eigen Systems will take anyColor BASIC or Extended ColorBASIC program for the TRS-80Color Computer and transfer itfrom cassette to a ROM (read-only memory) that plugs into theColor Computer's external port.Prices start at S45. Contact EigenSystems, POB 10234, Austin TX78766, (512) 837-4665.Circle 500 on inquiry card.

An ExpandableMicroprocessor Trainer

The Omnibyte Trainer 1 micro-processor training module can beexpanded from a simple teachingunit to a complete disk-based sys-tem. The main board of this two-board system contains a Motoro-la MC6808 microprocessor,1.25 K bytes of programmablememory, provisions for up to 4 Kbytes of PROM (programmableread-only memory), and onboardinput/output capability. Thisboard can function as a stand-alone computer. The trainer-inter-face board features an 8-digit dis-play, keyboard encoder, com-mand and data keys, and a hexa-decimal keypad. A 2 K-byte moni-tor program and hardware tracecircuitry are also included. Op-tionally available are parallel andserial interfaces, a data-rategenerator, and expansion-cardconnectors. The Trainer 1 pack-age contains a manual, all datasheets, schematics, monitorsource-code listing, and a bookon microprocessors. Prices rangefrom S349.95 to S526.45. Con-tact Omibyte Corporation, 245W Roosevelt Rd, Building 1-5,West Chicago IL 60185, (312)231-6880.

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Heath/ZenithSystems Sourcebook

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An Analysis of theCourseware Market

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Where Do New Products Items Come From?

The information printed in the new products pages of BYTE is obtained from"new product" or "press release" copy sent by the promoters of new products. Ifin our judgment the information might be of interest to the personal computing ex-perimenters and homebrewers who read BYTE, we print it in some form. Weopenly solicit releases and photos from manufacturers and suppliers to thismarketplace. The information is printed more or less as a first-in first-out queue,subject to occasional priority modifications. While we would not knowingly printuntrue or inaccurate data, or data from unreliable companies, our capacity toevaluate the products and companies appearing in the "Whaf s New?" feature isnecessarily limited. We therefore cannot be responsible for product quality orcompany performance.

October 1981 © BYTE Publications Inc 471

What's New?

MISCELLANEOUS

Rockwell's 68000

Rockwell International's Elec-tronics Devices Division has un-veiled the R68000 16-bit micro-processor. The device addressesup to 16 megabytes, has morethan 1000 instructions, and canprocess 8-, 16-, or 32-bit data.The R68000 can be sampled in 4and 6 MHz versions; an 8 MHzversion is under development.

Additional devices in theR68000 family will include a peri-pheral controller, a memory man-ager, a DMA (direct memory ac-cess) controller, and a multiproto-col communications controller.

The price for the 4 MHzR68000 is $210, the 6 MHz ver-sion is S220, and the projectedcost of the 8 MHz device is S250.Contact Rockwell International,Electronic Devices Division, 3310Miraloma Ave, POB 3669, Ana-heim CA 92803, (714) 632-2321.

Circle 505 on inquiry card.

FORTH on a ROM

Martin Schaaf's full Z80 fig-FORTH on a ROM (read-onlymemory) replaces the BASICROM in the TRS-80 Model I. Ascreen editor, 8080/Z80 assem-blers, and a metacompiler that re-produces FORTH from high-levelcode are included. The price isS250 from Martin Schaaf, POB1001, Daly City CA 94017.

Circle 508 on inquiry card.

48 K-Byte Boardfor the Atari

The MM48001 is a 48 K-byteprogrammable-memory board forthe Atari 400. It makes Atari 800software compatible with the400. The board costs S299. Con-tact Intec, Suite 111, 3387 DelRosa North, San Bernardino CA92404, (714) 864-5269.

Circle 499 on inquiry card.

ZEIM and theArt of Programming

ZEN is an operating system inthe North Star format using 5-inchfloppy disks. The system includesa word processor with line justifi-cation, file creation, and searchand insertions. The monitorcomes with memory testing,repeat cross-functions, and portcontrols. The assembler hasglobal labels, partial print designa-tion, stops, and trial assembly. It isavailable for $75 from ZenradControls Company, 1575 A P S,Santa Barbara CA 93103, (805)

965-4996. Circle 506 on inquiry card.

System 6220Counter/Timers

The System 6220 multifunctioncounter/timers can be combinedto provide an array of display andcontrol functions. Productionquantities, flow, rotation, dis-placement, frequency, andelapsed time can be measured inprocess monitoring, test systems,and production control. Pricesstart at • SI 15 for the 6222counter/timer. Contact NewportElectronics Inc, 630 E Young St,Santa Ana CA 92705, (714)

540-4914. Circle 509 on inquiry card.

CP/M Business Software

Rocky Mountain Software Sys-tems has a complete business-software system available forS199. The system is comprised offour software packages: GeneralLedger, Accounts Receivable, Ac-counts Payable, and Payroll.Written in MBASIC, the systemwill run on any CP/M-basedmicrocomputer with at least 48 Kbytes of programmable memory.Individual packages can be pur-chased separately for S59. Con-tact Rocky Mountain SoftwareSystems, POB 3282, WalnutCreek CA 94598.

Circle 512 on Inquiry card.

ComputerPollution Control

Electronic Specialists Inc, 171 SMain St, Natick MA 01760 (61 7)655-1532, has announced SuperIsolator, a device designed to con-trol electrical spikes, surges, andnoise. Super Isolator featuresthree individually filtered ACsockets. Equipment interactionsand disruptive or damagingpower-line pollution are con-trolled. The Super Isolator controlspollution for an 1875 W load.Each socket can handle a1000 W load. The Model ISO-3Super Isolator costs $94.95.

Circle 507 on inquiry card.

Memory Boardsfor the Atari

The AT-16, a 16 K-byte,200 ns memory board, and theAT-32, a 32 K-byte, 200 nsboard, are compatible with all ex-isting Atari 400 and 800 softwareand hardware. They install withno modifications. The AT-16costs $119.50, and the AT-32costs $199.50. Contact MicrotekPeripherals Corporation, 9514Chesapeake Dr, San Diego CA92123, (800) 854-1081; in Cali-fornia (714) 278-0630.

Circle 510 on inquiry card.

TRS-80 Space Raiders

Space Raiders is a machine-lan-guage program that creates a de-tailed simulation of outer spacecombat. Current and target posi-tion, fuel, shield energy, andheading are all displayed. Thereare five levels of play.

Space Raiders runs on 16 K-byte Level II TRS-80 Model I micro-computers. It is costs $24.95.Contact Bosen Electronics, 445 E800 North, Spanish Fork UT84660. (801) 798-9553.Circle 513 on inquiry card.

472 October 1981 © BYTE Publications Inc

What's New?

MISCELLANEOUS

64 K-ByteBoard for S-100 Systems

The OS]00 memory board isdesigned specifically for Sol,Cromemco, North Star, and otherS-100 systems. The 64 K-byte dy-namic board doesn't requireWAIT states at 2 or 4 MHz. It isaddressable in 4 K increments upto 512 K bytes. Features includeexpandability to 512 K bytes witha bank-select feature that allowsusers to select up to eight64 K-byte cards. The hidden re-fresh does not interfere withblock DMA (direct memory ac-cess) WRITE applications.

The CI-S100 costs $575. Con-tact Chrislin Industries Inc. 31352Via Colinas 102, Westlake VillageCA 91361, (213) 991-2254.Circle 541 on inquiry card.

Programmable Array-Logic Designers Kit

PALKIT is designed to acquaintengineers with the Program-mable Array Logic (PAL) family ofintegrated circuits. PAL circuitsare used to reduce the number of5400 and 7400 series compo-nents needed in circuit designs.By combining functions of TTL(transistor-transistor logic)devices, PAL circuits can reducetotal package count by as muchas 12 to I.

The kit contains one prepro-grammed master PAL circuit andseven unprogrammed circuits.Four of the unprogrammed de-vices are for combinatorial func-tions. The other three are for se-quential functions. A PAL datasheet, instructions for program-ming, a paper tape, and an engi-neering reference card are in-cluded. The PALKIT is availablefor $99.95 from Monolithic Mem-ories, 1165 E Arques Ave, Sunny-vale CA 94086, (408) 739-3535.

Circle 543 on inquiry card.

EPROM Programming

Logic Technology Services Inc(LTSI) is offering an EPROM(erasable programmable read-only memory) programming ser-vice. A program from a masterEPROM, truth table, or paper tapecan be reproduced to a compati-ble device, which is provided byLTSI. The service can be per-formed for 2704/2708s, 2716s,2732s and 2764s.

Fees range from $9.95 to$45.95, depending uponEPROM. EPROMs can be erasedfor $0.25 per device. A truth tablefor reproduction can be enteredfor an additional Sl5 per 1000words. A nonreturnable copy ofthe truth table should be pro-vided. Quantity prices are avail-able to clients who provide thecomponents.

For details, contact LogicTechnology Services Inc, 2400 EOakton, Arlington Heights IL60005, (312) 364-4670.

Circle 544 on inquiry card.

2 K-Byte ROMfrom Motorola

The MCM65516L43M is a2 K-byte CMOS (complementarymetal-oxide semiconductor) ROM(read-only memory). It is compati-ble with CMOS microprocessorsthat share address and data lines.The output-enable pin can beprogrammed for active high orlow, or MOTEL (ie: MOTorola, in-TEL) mode, which provides com-patibility with Motorola's 6800series or Intel's 8085 microproces-sors. A monitor program for theMotorola CMOS MCI46805E2microprocessor is included on thisROM. Contact the MOS Inte-grated Circuit Division, MotorolaSemiconductor Products Inc, Aus-tin TX 78721, (512) 928-6660.

Circle 542 on inquiry card.

Flber-Optlc Transmitterand Receiver Modules

The MFOL02T fiber-optic trans-mitter and the MFOL02R receivermodules are designed for digital-communication systems. Thetransmitter module incorporatesan LED (light-emitting diode) withan output of 70 /tW, which canprovide data transmission over adistance of I kilometer; greaterdistances can be achieved withother cables and emitters. The re-ceiver has a bandwidth from DCto 200 kbps (bits per second), adynamic range of 25 dB, and isTTL- (transistor-transistor logic)compatible. The modules arecompatible with plastic- or glass-fiber cable and operate from asingle + 5 V supply. Full-duplex,star, daisy chain, and other sys-tem designs can be achieved.

The MFOL02T costs $36.80,and the MFOL02R costs $42.50.Contact Motorola SemiconductorProducts Inc, POB 20912, Phoe-nix AZ 85036, (602) 244-4556.

Circle 545 on inquiry card.

October 1981 © BYTE Publications Inc 473

What's New?

MISCELLANEOUS

Universal Card Cage

The CCK-80 card cages letdesigners package systems usingSeries-80 Multibus, S-100, Mo-torola, and Rockwell microcom-puters and accessory cards. Thefully adjustable, ten-board cagesare priced at S79 each.

Additional space along the sideof each cage can hold two fansand can be used for power sup-plies or other equipment. The rearcross members accept card-edge

connectors or motherboards. Thecage fits any standard 19-inchrack and weighs five pounds.

Cage accessories include card-edge connectors, bottom- andside-hinged front panels, latches,screw-attached front panels, topand bottom covers, handles, andtilt-up feet. Contact Vector Elec-tronic Company, 12460 Glad-stone Ave, Sylmar CA 91342,(213) 365-9661.Circle 514 on inquiry card.

Keyboard Actuator

When interfaced with micro-computers, such as the TRS-80,PET, or Apple, the KGS-80 key-board actuator turns IBM Selectricand SCM typewriters intoprinters. The KGS-80 rests on thetypewriter keyboard and plugs in-to the computer's printer inter-face. No modifications are neces-sary and no software is requiredto operate the device. Details onthis S599 peripheral can be ob-tained from Kogyosha CompanyLtd, I 79 Riveredge Rd, Tenafly NJ07670, (201) 569-8769.

Circle 515 on inquiry card.

Prevent Static Damage

Wescorp has static-dissipativedesk and bench covers of softvinyl to protect products fromstatic electricity damage. The WS-227-1B Stat-Mat reduces vibrationand glare and is water and chem-ical resistant. Static resistancemeets DOD (Department of De-fense) handbook specifications.The covers are available in 2- and4-foot widths cut to any lengthup to 100 feet. The cost is $4 persquare foot.

Conatct Wescorp, I I 55 TerraBella Ave, Mountain View CA94043, (41 5) 969-7717.

Circle 517 on inquiry card.

64 K-Byte Static MemoryBoard for the S-100 Bus

The RAM 17 is a 64 K-bytestatic board for S-100 microcom-puters. It is guaranteed to runwith 6 MHz Z80s and 10 MHz8086/8088S. The board featurespower dissipation of less than2 W and 24-bit addressing. TheRAM 17 can be addressed on any64 K page boundary and can bedisabled in 16 K blocks. The upper8 K block can have 2 K windowsdisabled for memory-mappedperipherals.

RAM 1 7 uses 2 K by 8-bit staticintegrated circuits that are com-patible with 2716 EPROMs (eras-able programmable read-onlymemory). Prices range from$1095 to SI595. Contact Com-puPro, Godbout Electronics, POB2355, Oakland Airport CA94614, (415) 562-0636.Circle 516 on inquiry card.

Color-GraphicsDisplay Controller

The NEC tiPD7220 integratedcircuit operates between thevideo-display memory and themicroprocessor bus. It performsmost of the tasks required togenerate displays and to managedisplay memory. Compatible with8080/8085/8086, Z80, 6800, andother processors, the device mini-mizes host-processor softwareoverhead. It features DMA (directmemory access) control, graphicsfigure-drawing capabilities, and alight-pen input. The unit has a 5MHz clock rate and requires asingle + 5 V supply.

Samples of the /*PD7220 arepriced below S100. Contact NECMicrocomputers Inc, 173 Wor-cester St, Wellesley MA 02181,(617)237-1910.

Circle 518 on inquiry card.

474 October 1981 © BYTE Publications Inc

What's New?

PUBLICATIONS

Catalog of More Than2000 Rental Items

Genstar Rental Electronics Inc,which specializes in the short-term rental of electronic equip-ment, has a free catalog that listsits rental items. The catalog isdivided into 47 categories thatrange from amplifiers to testchambers. There are analyzers,generators and meters of alltypes, plus microcomputers,microprocessor instrumentation,PROM (programmable read-onlymemory) programmers, oscillo-scopes, and data terminals. Foryour copy, contact Genstar Ren-tal Electronics Inc, 19527 BusinessCenter Dr, Northridge CA 91324,(213)993-7368.

Circle 519 on inquiry card.

Directory of RoboticsProducts

The Robotics Industry Direc-tory contains a summary of theavailable products in the roboticsindustry. Robots, robot subsys-tems, components, general tech-nical specifications, pricing data,and marketing contacts arefeatured. Also included is infor-mation on consulting firms, per-sonnel recruiting, engineeringdesign, systems integration, andcustom-manufacturing. The finalsection provides information onthe activities of public organiza-tions, university research, andprivate research laboratories. TheDirectory costs S24.95. ContactRobotics Industry Directory,POB 725, La Canada CA 9I0I I,(213) 352-7937.Circle 520 on inquiry card.

Man/MachineCommunications

Speech Technology is aquarterly magazine concerningman and machine communica-tions. It deals with the state of theart in voice synthesis and recogni-tion for the engineer, scientist,educator, manager, and otherusers. Articles on linear-predictivecoding, adding word recognitionto a system, and new ap-plicatons, such as a voice-activated door lock, are amongthe topics covered. New prod-ucts, events, and a newsletter arealso featured. A one-yearsubscription is S50 from MediaDimensions Inc, 525 E 82nd St,New York NY 10028, (212)680-6451.

Circle 521 on inquiry card.

SUNNY LOW LOW^OST

POWER SUPPLIES

FOR S-100, FLOPPY DISKS.

KIT 1, 2 & 3

For Three 8" or51/»" Disk Drives

S-100 POWER SUPPLY KITS (open frame with base plate, 3 hrs. assy, time)

ITFM

USED FOR

@ - 9 Vdc

: H

S3 2 in 1 Unit for S-100 andtwo 8" or 5'A" Disk Drives. It fitsmost Disk System Mainframes.

PRICE

KIT 1 15 CARDS SOURCE 15A

KIT 2 SYSTEM SOURCE 25A

KIT 3 DISK SYSTEM 15A

1A

2.5A3A2A

2.5A3A2A

4A

12"12"14"

4%"

w

47/a"

52.9559.9567.95

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'/„" (D) x 4%" (H). 2) 9" (W) x 47/8" (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 5'j 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) * e <d> * 5" (hj 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 5".," DISK DRIVES

POWER TRANSFORMERS (with mounting brackets)

ITEM PRIMARY SECONDARY #1 SECONDARY #2 SECONDARY #3 SIZE W x D x H PRICE

Ti

T2T3T4T5

110/120110/120110/120110/120110/120

2x8 Vac. 15A2x8 Vac, 25A2x8 Vac, 15A2x8 Vac, 6A2x8 Vac. 6A

28 Vac, CT, 2.5A28 Vac, CT, 3.5A28 Vac, CT, 2.5A28 Vac, CT, 1.5A2S Vac, CT, 2A

48 Vac, CT, 2A48 Vac, CT, 3A

3%"

3V-."

3%"

33/V

3"

x 35/s" x 3Va"x 43/a" x 3Va"x 43/e" x 3Vb"x 35/a" x 3Va"x 3" x 2Vs>"

21.9527.9529.9522.9514.95

SHIPPING For each power supply $5.50 inCalif., $7.50 in other states, $14.00 in CanadaFor each Transformer $5.00 in all States,$10.00 in Canada. Calif. Residents add 6%Sales Tax.

MAILING ADDRESS:iaia P.O. BOX 4296

"SO TORRANCE, CA 90510

TELEX: 830-5010

ANSWER BACK FOR TELEX SUNYCO TRUC

SUNNY INTERNATIONAL

(TRANSFORMERS MANUFACTURER)(213) 328-2425 MON-SAT 9-6

SHIPPING ADDRESS:22129% S. VERMONT AVETORRANCE, CA 90502

October 19B1 © BYTE Publications Inc 475

What's New?

PUBLICATIONS

S-100 Products Catalog

Ackerman Digital Systems Inc.the maker of processor boardsand other items.for S-100 sys-tems, has published a catalog ofits products. Music and 6809 pro-cessor boards, PROM (program-mable read-only memory) pro-grammers, and other devices aredescribed in the catalog. For acopy, contact Ackerman DigitalSystems Inc, HON York Rd, Elm-hurst IL 60126, (312) 530-8992.

Circle 523 on inquiry card.

Electronic Learning

Electronic Learning magazine isa bimonthly publication for educa-tors who buy and use electronichardware and software in elemen-tary and secondary education. Anontechnical source of ideas andinformation, it includes articles onthe use of microcomputers, videocassettes, videodiscs, and otheraids in education. For more infor-mation, contact Scholastic Inc, 50W 44th St, New York NY 10036,(212) 944-7700.Circle 524 on inquiry card.

Looking for a CertainPublication?

The Westlake Guide listsperiodicals and offers package sub-scriptions for computer, electronics,video, telecommunications, andbusiness publications. A copy ofthe guide costs $ 1. Contact West-lake Subscription Service, 4200 SLouise, Sioux Falls SD 57106, (605)331-6930.

Circle 522 on inquiry card.

Apple SoftwareDirectories

Apple Software Directories is athree-volume set that lists availablebusiness, games, and educationalsoftware for Apple computers. It in-cludes the names and addresses ofmore than 400 software vendors.

The Apple Softare Directory-Volume 1: Business Guide costsS5.95. Volume 2: Games Direc-tory costs S4.95. Volume 3:Educational Guide costs $5.95.Contact WIDL Video, 5245 WDiversey, Chicago IL 60639, (312)622-9606.

Circle 526 on inquiry card.

UNIX ProductsList Available

A directory of UNIX and C prod-ucts is now available on a subscrip-tion basis from InfoPro Systems.The UNIX software list includessuppliers of UNIX, C compilers andinterpreters, data-base systems,other languages on UNIX, applica-tions and business packages, usergroups, utilities, hardware vendors,and UNIX-like systems. A yearlysubscription to the UNIX SoftwareList is S18. For details, contact In-foPro Systems, POB 33, East Han-over NJ 07936, (201) 625-2925.

Circle 527 on inquiry card.

Computers In ScienceTeaching

The Journal of Computers inScience Teaching is a quarterlypublication on the use of comput-ers in science instruction. It featuresresearch studies on teachingscience and tutorials. There are listsand reviews of science software,announcements of conferencesand events, and book reviews. TheJournal of Computers in ScienceTeaching is published by the Asso-ciation for Computers in ScienceTeaching, POB 4825, Austin TX78765, for $7 per year.

Circle 525 on inquiry card.

ComputerMerchandising

Computer Merchandising

covers sales and manufacturingin the computer industry. It in-vestigates the ebb and flow of theeducational computer market-place, peripherals, and promo-tions to increase sales. Interviewswith people in the industry arealso featured. This monthlypublication costs $18 per yearand is available from ComputerMerchandising Magazine,15720 Ventura Blvd, Suite 610,Encino CA 91436, (213)995-0436.

Circle 529 on inquiry card.

Educational Computer

Educational Computer is an

information exchange for ele-mentary, high school, college,and university students and edu-cators. In its pages. EducationalComputer addresses such topicsas the impact of microcomputersin schools, colleges, and univer-sities. Also, separate departmentsfeature letters from readers, edi-torials, book reviews, events, clas-sified ads, and administrativefeedback. The yearly subscriptionrate (6 issues) is $12. ContactEducational Computer Maga-zine, POB 535, Cupertino CA95015, (408) 252-3224.Circle 530 on inquiry card.

IEEEPublications Catalog

A publications catalog is avail-able from the Computer Society ofthe IEEE (Institute of Electrical andElectronics Engineers). The cataloglists more than 300 publicationsand covers all aspects of applica-tions, methodologies, and tech-niques in computer software andhardware. It also contains tech-nical-level tutorial texts for the com-puter scientist and engineer. For afree copy of the 1981 Pubs Cata-log, write to the Computer SocietyPress, POB 639, Silver Spring MD20901.

Circle 528 on inquiry card.

476 October 1981 © BYTE Publications Inc

DEALS □ DEALS □ 0£>US

SHOP HERE AND

0

10

(MINIMUM ORDER $10.00)

777/s as ABSOLUTELY the LOWEST PRICE EVERfor a Hi Speed (300 NS) LO-LO Power 32K RAM. (Q4K by 1 Chips are organized in Selectable Banks. ^ [)

* Extended Address Lines A16 ■ A17• Phantom Line * 9 Regulators

(KIT)

;^ati«KlJSai3ej.t--i>l.»3J:fc..'.i.Bi:jJi^.l

rsot

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Imniinnifflninnl'

S-100 BOARDS and ACCESSORIES

Z — 80 CPU

The first time this world

popular CPU offered in

Kit. Two serial, 3 parallel,

CTC, EProm Z-80 at

4 mhz. Software buad

rate, etc. (Less Prom. & Cable) $250.00

S1 — MOD (KIT)$199.00 (ggj^

<#

Complete S-100 12 Slot Computer. Amplesystem power with regulated power for drives.Excellent for Subsystem or Hobby use.Four hours to build. (6 conn., Inert., less fans)

S-100 CARD EXTENDER$12.50

(Gold Contacts)

As long as there is a pricewar, we will fight yourbattle. Compare at yourlocal Department store andbuy U$ MICRO.

EXPANDABLE RAM

• 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 • $400.00 A&T •

U$ — D$K $275.00

Double Density 8" and 5"Disk Controller designedfor S-100 IEEE standards.Uses Western Digital1795.1691. 2143ChipSet.

S-100- CONNECTOR

Tl or Belter

SOLDER TAIL

$2.50

CCS S—100

2810 CPU

Only — $250.002422 Dsk Cont

Only — $300.002065C 64K

Only — $425.002032C 32K

Only — $620.002718 2x2

Only — $305.002200A Mainframe

Only — $349.002501 Mother Board

Only — $106.002116C16K Static Ram 200ns

Only — $309.002520K Extender Board

Only — $ 52.00

CHIPS - CHIPS - CHIPS - CHIPS -

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 ?)

2716s $7.75 (450 NS)2708s $4.75 (450 NS)

Remember when 2716s were $50.00 and hard toget? These units are so beautiful it's hard to partwith them. But we will, for a small price.Guaranteed!

4116s

Expansion 16K Dynamic RAMs $2 50for Apple. TRS-80 S-100 ™ "

systems. T.I., Mostek Intel.Call for manufacturer. #»»»#» •.••»

200 NS

2114s

One of the world's two mostpopular STATIC RAMs.Factory prime tested unitsSold in lots of 8 only.FUJITSU, HITACHI, etc.

$2.75 ea,

200 NS

TMS-4044 $4.00MM — 5257 ^

INTEL 2147

250 NS

The other of the world's most popular STATICRAMs. This one is 4K by 1 organization.

U.S. Micro Sales can also supply a vast array of IC's.Because of space limitations we can not list them all.We can also supply power supplies - sockets - heat sinks - tools

etc., etc., etc.

Please Call For Pricing & Availability

Circle 375 on inquiry card.

What's New?

MISCELLANEOUS

Votrax Speech Circuit

The SC-01 speech-synthesizerintegrated circuit combines elec-tronically generated phonemes toproduce an unlimited vocabulary.Votrax's technique doesn't limitthe number of words and phrasesto a fixed amount or format assynthesizers that reconfigurewords and phrases from prere-corded human voice tracts do.Designers can build their own vo-cabulary through a system thatcontains an algorithm that auto-

matically translates English text in-to phonemes. One second ofspeaking time requires 70 to 100bits of memory with this device.The speech-synthesizer chip isavailable at prices starting at $95each, for a minimum of five units.The Vodex Sales Division ofVotrax Inc is located at 500 Ste-phenson Hwy, Troy Ml 48084,(800) 521-1350; in Michigan(313) 588-0341.Circle 536 on inquiry card.

Swltched-On DOS

The DOS Switch allows aDOS-3.3-equipped Apple II toboot either DOS 3.3 or 3.2 floppydisks without need of the BASICSdisk. The switch doesn't requiresupport software or modificationsto established 3.2 disks. The de-vice plugs into the Apple withoutsoldering or permanent wiringchanges. The DOS 3.3 P5A bootPROM (programmable read-onlymemory) and the DOS 3.2 P5boot PROM are needed for in-stallation. The DOS Switch costsS29.95 and is available from theMicro Computer Center, 7900Paragon Rd, Dayton OH 45459,(513) 435-9533.Circle 537 on inquiry card.

Aid for thePhysically Disabled

The Viewpoint Optical Indica-tor is an incandescent lampmounted onto a headband. It en-ables the physically disabled in-dividual with good head controlto indicate objects, words, orsymbols on a manual-communi-cation board. The band can beworn on the head, hand, orwrist. The lamp can be positionedfor use in a wheelchair, bed, oron a prone board. A rechargeablepower-pack stores a day'scharge. The device costs SI89and is available from PrentkeRomich Company, RD 2, POB191, Shreve OH 44676, (216)

567-2906. Circle 538 on inquiry card.

5 to 15 V DC DualPower-Supply Kit

The JE215 power-supply kitprovides adjustable regulatedpositive and negative output volt-ages from 5 to 15 V DC. Poweroutput for each supply rangesfrom 5 V DC at 500 mA to 15VDC at 1 75 mA. The JE21 5 kit re-tails for $24.95 from Jameco Elec-tronics, 1355 Shoreway Rd, Bel-mont CA 94002, (415) 592-8097.Circle 540 on inquiry card.

PROMs with Tltanlum-Tungten Fuses

Monolithic Memories' line of1 K- and 2 K-byte PROMs (pro-grammable read-only memories)uses titanium-tungsten (TiW)fuses and requires only 70 mA ofcurrent with no loss in speed. Ac-cess times are 55 ns for the 1 KPROM and 60 ns for the 2 K de-vice. Pin-compatible with stan-dard Schottky PROMs, these unitsare organized as 256- by 4-bit and512- by 4-bit arrays. The PROMshave full Schottky clamping,three-state or open-collector out-puts, and transistor inputs forlow-input current. A new pro-gramming technique eliminatesthe need for a separate pro-gramming pin as found on Ni-chrome-fused PROMs.

Prices range from S3.75 to$10.55. Contact MonolithicMemories, 1165 E Arques Ave,Sunnyvale CA 94086, (408)

739-3535. Circle 539 on inquiry card.

478 October 1981 © BYTE Publications Inc

WE WILL NOT BE UNDERSOLD

DISK DRIVES

FOR TRS-80* Model I

CCI-100 5V4", 40 Track (102K) $299

ADDON DRIVES FOR ZENITH Z-89CCI-189 5V<", 40 Track (102K) $394

Z-87 Dual 5 Va" system $995

External card edge and power supply included. 90 day warranty/oneyear on power supply.

RAW DRIVES5V4"TEACorTANDON

8"SHUGART801R

DISKETTES - Box of 10

5Va" Maxell $40

8" Maxell $45

BASF/VerbatimBASF/Verbatim

PLASTIC FILE BOX-Holds 50 5 V« " diskettes

PLASTIC LIBRARY CASEHEAD CLEANING DISKETTEFLOPPY SAVER $10.95

5Va" $3.00

RINGS

2 for $37Jumpers

$CALL$CALL

$26.95$36.00$19.00$ 4.00$25.00$ 6.95

$19

$2.50

16K RAM KITS

200ns forTRS-80,*Apple II, (specify):

SYSTEM SPECIAL

Apple II Plus 48K w/drive and controller. Epson MX-80 printer andinterface. SUP-R Mod. RF Modulator: List $2965 You Pay $2299

COMPUTERS/TERMINALS

ARCHIVES 64K, 2-Drives, 77Track $CALL

ALTOS ACS8000 Series $ CALL

ZENITH 48K, all-in-one computer $2200

ZENITH Z-19 $ 725

TELEVIDEO 910 $559 920C $ 729 950 $1039

IBM 3101 Display Terminal $1189

ATARI 400 $ 359 800 $ 795

MATTEL INTELLIVISION $ 259

APPLE PERIPHERALS $CALL

S-100 CALIFORNIA COMPUTER SYSTEMS

MAINFRAME

Model 2200A

Z80 CPU

Model 2810

MOTHER BOARD

Model 2501

16K STATIC RAM, 200ns

Model 2116C

32K STATIC RAM, 200ns

Model 2032C

64K DYNAMIC RAM

Model 2065C

FLOPPY DISC CONTROLLER

Model 2422A

EXTENDER BOARD

Model 2520K

2P + 2S I/O

Model 2718A

$349$259$106$309$619$580$345$ 52$309

PRINTERS

NEC SPINWRITER

Letter Quality High Speed Printer

R.O.

R.O. with tractor feed

KSR with tractor feed

NEC SPINWRITER 3500 SeriesEPSON MX-70 MX-80

PAPER TIGER

MX-80FT MX100

IDS 445IDS 460IDS 560

ANADEX

OKI DATAMicroline 80Microline 80Microline 82Microline 83

CENTRONICS

C. ITOHStarwriter IStarwriter IStarwriter IIStarwriter II

Graphics &2K bufferGraphics & 2k bufferGraphicsDP-8000 $849

Friction & pin feed

Friction, and pin & tractor feed

Friction & pin feed

120 cps, uses up to 15" paper

739, new model with graphics

25 cps, parallel interface25 cps, serial interface45 cps, parallel interface45 cps, serial interface

DP-9500/01

PRINTER SPECIAL

SEIKOSHA GP-80M

MONITORS

BELL&

HOWELLLEEDEX

List $399

$2395$2555$2795

$CALL

SCALL

$ 695$ 799$ 999$1295

$CALL$CALL$CALL$CALL$ 739

$1449$1529$1829$1949

You Pay $319

1213'91213

B&WBHD911B&W $129

ColorB&WB&WColor

$329$149$219$349

$175

12" Green Screen $159

12" Green Screen $23813" Color $406

12" Green Screen $129

SANYOZENITH

TELECOMMUNICATIONS

LIVERMORE STAR MODEM 2-year guarantee $125

UNIVERSAL DATA SYSTEMS UDS-103 $179

D-CAT HARD WIRED DIRECT MODEM $189

AUTO-CAT Auto Answer, Direct Connect Modem $249

APPLE-CAT II $349

D.C. HAYES MICRO-MODEM $295

D.C. HAYES SMART-MODEM $235

CCI Telnet Communications Package $135

APPLE ACCESSORIES AND SOFTWARE

VISICALC $155.00

CPS MULTIFUNCTION CARD

Z-80 SOFTCARD

VIDEX BOARD

KEYBOARD ENHANCER

16KCARD

APPLE JOYSTICK

SUP-R MOD

CCS CARDS

GALAXIAN

SPACE ALBUM

ASTEROIDS

FLIGHT SIMULATOR

WIZARDS PRINCESS

SARGON 2

MYSTERY HOUSE $ 24.00

DB MASTER

HI-RES FOOTBALL

$159.00$189.00$259.00$255.00$110.00$159.00$ 49.00$ 25.00$CALL$ 22.95$ 35.00$ 17.95$ 29.00$ 28.00$ 29.00$ 35.00

For fast delivery, send certified checks, money orders or call to arrange direct bank wire transfers. Personal or company checks require twoto 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 for FREE Catalogue

TO ORDER CALL TOLL FREE 1-800-343-6522

TWX: 710-348-1796 Massachusetts Residents call 617/242-3361

The CPU SHOP

5 Dexter Row, Dept. B10MCharlestown, Massachusetts 02129Hours 10AM-6PM (EST) Mon.-Fri. (Sat.

till 5)

Technical Information call 617/242-3361Massachusetts Residents add 5% Sales TaxTandy Corporation Trademark^Digital Research

Circle 107 on inquiry card.

BYTE October 1981

479

What's New?

MISCELLANEOUS

High-ResolutionTouch Screens

With the TSD 12- and 15-inchTouch Screen Digitizers, you canenter data by touching a comput-er display with your finger. Thescreen's high-resolution also per-mits the entry of graphic data.The Touch Screens can be retrofit-ted onto existing video displays,and in most cases no modifica-tions are necessary. The thin,transparent, curved panel, consis-ting of two conductive films sepa-rated by an insulating space,mounts in front of the video dis-play; an interface board is con-nected to the panel with a cable.When the panel is touched, oneconductive layer touches theother, yielding a voltage that isconverted into the necessary in-formation and transmitted as anRS-232C message or a parallel8-bit, 3-state message.

The 12-inch model costs S650and the 15-inch device is priced atS 700. Contact TSD Display Prod-ucts Inc, 35 Orville Dr, BohemiaNY 1 1716, (516) 589-6800.Circle 531 on inquiry card.

16 K-Byte ProgrammableMemory Circuits

Fujitsu Microelectronics has afamily of 16 K-byte dynamic pro-grammable-memory integratedcircuits with single 5 V power-supply reguirements and accesstimes as fast as 100 ns. TheMB811 7 and MB81 18 devices areavailable with 100 or 235 ns cy-cle times.

Features include 182 mWpower dissipation, bias generator,read-write-modify, hidden re-fresh, page-mode capability, andTTL- (trasistor-transistor logic)compatible inputs. Contact Fujit-su Microelectronics, 2945 Oak-mead Village Ct, Santa Clara CA95051, (408) 727-1700.Circle 532 on inquiry card.

EPROM HasHigh Standards

Advanced Micro Devices has a32 K-bit EPROM (erasable pro-grammable read-only memory)that meets the MIL-STD-883 andINT-STD-123 guality standards.Organized as 4 K bytes by 8 bits,the Am2732 operates from asingle + 5 V supply. It offersthree-state outputs, fully staticoperation, and a two-line controlthat makes Chip Enable and Out-put Enable available. This elimi-nates bus contention and theneed for external buffers and chipcontrols.

The Am2732 costs S31.50.Contact Advanced Micro De-vices, 901 Thompson PI, Sunny-vale CA 94086, (408) 732-2400.Circle 533 on inquiry card.

In-ClrcultMicrocomputer Tester

Patuck Inc's microcomputeranalyzer is a hand-held devicethat clips directly to the micropro-cessor to be tested by means of a40-pin chip clip. It can single-stepthe microprocessor or let it runfree to a selected error vector ortrap address. A trace capabilityallows examination of the 63 ma-chine cycles that precede break-point. Interchangeable interfacesare available for Z80-, 8080/85-,6502-, 6800-, 2650-, 6802-, and6501-based microcomputers.

The Microcomputer Analyzercosts S829. Interfaces are S6Ieach. Contact Patuck Inc, 5073Russell Ave, Pennsuaken NJ08109, (609) 662-0677.Circle 534 on inquiry card.

PROM Copler/Verlfler

The cloneAprom PROM (pro-grammable read-only memory)copier/verifier duplicates a 5 Vmaster 2716 EPROM (erasablePROM) in 138 seconds. It featurestwo ZIF (zero insertion force)sockets, pass/fail indicators, and a

power supply. Both a 2732 and a220 VAC, 50 Hz version areavailable.

The cloneAprom costs S299.Contact Alloy Engineering Com-pany Inc, 12 Mercer Rd, NatickMA 01760, (617) 655-3900.Circle 535 on inquiry card.

480 October 1981 © BYTE Publications Inc

JBEI MICROCOMPUTER

John Bell Engineering's low-cost JBE I Microcomputer - based on the powerful 6502 processor - is specifically designed for WORK,LEARNING, DEVELOPMENT AND CONTROL. The JBE I has a unique combination of features:

• 6502 Microprocessor

• 4 6522 VIAs (8 parallel I/O ports)

• 1 AY5-1013 (UART serial port)

• Cassette Interface

• 4K 2114 RAM Memory

• 8K or 16K EPROM Memory

• Monitor and Tiny Basic

• Variety of Support Cards

• Use your JBE I to PROGRAM 2716s, TALK to you, CONTROL the world.

• JBE I interfaces with JBE's EPROM Programmer, Parallel Input Speech Synthesizer, A-D & D-A Converter and Solid StateSwitches.

• Save your programs easily and accurately using the cassette interface.

• Use your JBE I for:

CONTROL

• Home security and lighting systems

• Irrigation systems

• Model Tranis

• Solar heating and power systems

DEVELOPMENT

• Software for work and home

• Learning aids for children at home and school

• Development system for JBE 6502 Microcomputer

LEARNING

• Microcomputer Technology

• Machine language and Basic programming

• The three R's for children

JBE I is available fully populated, partially populated or as abare board for OEM and the dedicated hobbyist:

The fully populated version includes:

6502 CPU 4K RAM

4 6522 VIAs Monitor EPROM

A Y5-10I3 Tiny Basic EPROM

Partially Assembled Version includes:6502 CPU IK RAM

1 6522 VIA Monitor EPROM

A Y5-1013

All versions include complete documentation. For informationwrite: John Bell Engineering, P. O. Box 338, Redwood City,CA 94064. (415) 367-1137. OEM Pricing available.

FOR MASTER CHARGE, VISA AND C.O.D. ORDERS CALL (415) 367-1137 OR SEND CHECK TO THE ABOVE ADDRESS,DEPT JI. PLEASE INCLUDE 5% FOR SHIPPING AND HANDLING INSIDE USA AND 10% OUTSIDE USA.

What's New?

SYSTEMS

Mlcrollte Microcomputer

The Microlite microcomputer isa self-contained system that in-cludes the microprocessor, key-board, 24-line by 80-characterplasma display, and two 5-inchfloppy-disk drives capable ofstoring up to 350 K bytes. Micro-lite has provisions for serial com-munications.

Options for the Microlite in-clude a dot-matrix printer that canbe housed in the console andsupport for up to four 8-inchfloppy-disk drives. Hard-diskdrives are also available. For moreinformation on the Microlite II,contact Ql Corporation, 125Ricefield Ln, Hauppauge NY1 1787, (516) 543-7800.Circle 590 on inquiry card.

Pascal DevelopmentSystem for CP/M

The PDS-80 Pascal Develop-ment System for CP/M applica-tions is designed with the systemsintegrator and applications-soft-ware developer in mind. A CacheBIOS for CP/M uses the DMA (di-rect-memory access) and inter-rupt capabilities of the disk con-' trailer and memory to bufferwhole tracks in extended mem-ory, which speeds up executiontimes.

Included in the system isPascal/Z, a native-code compilerthat generates ROMable (read-only memory) and reentrant ob-ject code, relocatable objectmodules, and permits separatecompilation. A 2.4-megabytedual-disk drive, choice of main-frame, Cache BIOS, Pascal/Z, andCP/M come with the develop-ment system. Five utilities are alsoincluded: InterEdit, a screen-oriented editor; Spell, a spellingeditor with a 10,000-word modi-fiable dictionary; Quickopy, forcopying disks faster than the PIPutility; Help, an access to docu-mentation; and Compare, a quickview of the difference betweentwo files.

The PDS-80 Development Sys-tem costs S7995. Contact IthacaIntersystems Inc, 1650 HanshawRd, Ithaca NY 14850.

Circle 591 on inquiry card.

Datamac Series 1200

The Datamac 1200 series ofmicrocomputers can be expand-ed with external floppy-disk drivesof any density, track, or side con-figuration. Provision is made forusing the video display to setbreakpoints and single-stepthrough programs for debugging.Among the models available isthe 1255 microcomputer. It con-tains a Z80 microprocessor, 64 K

bytes of programmable memory,input/output ports, keyboard,video display, dual 5-inch double-sided double-density disk drives,and the CP/M operating system.The Model 1255 with twodrives capable of storing 780 Kbytes lists for S4695. ContactDatamac Computer Systems,3333-F Octavius Dr, Santa ClaraCA 95051, (408) 727-0561.Circle 593 on inquiry card.

Omninet from Corvus

Omninet is a 1 -megabyte-per-second network that uses ashielded twisted-pair cable forconnecting microcomputers. Thenetwork allows the interconnec-tion of up to 64 microcomputersand peripherals in a 4000-footserial link. The intelligent compo-nent of the system is the Omninettransporter, which interfaces tothe microcomputer or peripheraland provides for the transfer ofmessages without software inter-vention or requiring a control pro-cessor. Omninet will work withCorvus Constellation software,providing up to 80 megabytes ofshared storage.

Available for the Apple II, OnyxC8000, and Digital EquipmentCorporation LSI-1 1 computers,Omninet will also connect to allCorvus peripherals. Future trans-porters are being designed forTRS-80, Apple III, S-100, Atari,Commodore, Altos, and otherpopular microcomputers.

Omninet transporter units arepriced at S495 for the Apple II andS-100, S 750 for LSI-1 1 computers,and S650 for the Onyx C8000. Adisk server for Corvus Winchesterdisks will retail for S990. For moreinformation, contact Corvus Sys-tems Inc, 2029 OToole Ave, SanJose CA 95131, (408) 946-7700.

Circle 592 on inquiry card.

10 MHz 68000

Motorola Semiconductor Grouphas announced the availability ofa 10 MHz MC68000L10 micro-processor. Samples are availablefor $449. Contact your local Mo-torola representative or the Moto-rola Semiconductor Group, 3501Ed Bluestein Blvd, Austin TX78721, (512) 928-61 19.

Circle 594 on Inquiry card.

482 October 1981 © BYTE Publications Inc

COMPUTER STOP

2545 W. 237 St. Torrance, CA. 90505

ORDER BY PHONE

MON.-SAT.

10-6

(213) 539-7670 PSTTELEX: 678401 TAB IRIN

LOWEST PRICES IN THE WEST.NORTH. SOUTH & EAST

jcippkz computer 1-800-421-1947

Sales and Service

NEC 8001A $1100

NEC 8012A $ 750

NEC 8031A $1100

NEC RGB Monitor $ 999

NEC General AccountingSystem $ 350

APPLE HARDWARE

Parallel Printer Interface Card 160

Communications Card 195

High Speed Serial Interface 160

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

AH 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

DoubleVlslon 80 x 24 Video Interface 245

CCS Arithmetic Processor 399

CCS Parallel Interface 119

16K Ram Card 145

Microworks DS-65 Digisector 339

SVA8inch Disk Controller 350

Sup-R-Mod 30

CCS Synchronous Serial Interface 159

CCS Asynchronous Serial Interface 159

Corvus 10 Meg. Hard Disk 4395

Corvus Constellation 595

MISCELLANEOUS/SUPPLIES

16K RAM (200-250 NS) 29

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

MICRO MODEM II

$295

Z-80 Softcard

$299

MONITORS/DISPLAYS

Leedex Video 100 12" 140

Sanyo9" 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 650

IDS 460 with Graphics 1049

IDS 560 with Graphics 10) 1199

Centronics 737 795

NEC Splnwriter(RO, Serial) 2650

SOFTWARE

The Controller 525

Apple Post (Mailing List Program) 45

Easywriter Professional System 195

Apple Pie 2.0 110

DB Master Data Management 175

The Cashier 210

Apple Writer 65

Vlslcalc 175

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 45

Data Factory DMS 110

Apple Plot 55

Apple Pilot 120

Magic Wand Word Processor (Needs Z-80 Softcard) 345

Dow Jones Portfolio Evaluator 45

Fortran 140

ORDERING INFORMATION: Phone orders invited using VISA, MASTERCARD or bank wire transfers. VISA & MC credit card service charge ot 2%.

Mail order may send charge card number (include expiration date), cashier's check, money order or personal check (allow 10 business days to clear.) Piease include a telephonenumber with all orders. Foreign orders (excluding Military PO's) add 10% for shipping. All funds must be in U.S. dollars (letters of credit permitted). Shipping, Handling and in-surance 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 forwritten quotation). All equipment is subject to price change and availability. Equipment is new and complete with the manufacturer warranty. We do not guarantee merchantibilityof products sold. All returned equipment is subject to a 15% restocking fee. We ship most orders within 2 days.

WE ARE A MEMBER OF THE 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 October 1981

483

What's New?

SYSTEMS

New Z80 Board

The CPC-2810 Z80-based pro-cessor board is designed for theS-100 bus. It features two or fourserial I/O (input/output) channels,software-selectable data rates,two parallel I/O channels withhandshaking, eight vectoredpriority interrupts, and compatibil-ity with most disk controllers. Allasynchronous serial channels canbe made fully synchronous. I/Ointerfaces are customized throughthe use of external personalityboards. The CPC-2810 Z80 boardcosts S495 from Measurement Sys-tems & Controls, 1601 Orange-wood, Orange CA 92668, (714)

633-4460. Circle 595 on inquiry card.

. i^ttd&i&w.

IBk.»-*

^^ ™

|^v

IfeX

^t^*

!^S

A Very Portable Terminal

LEX 21 is a small, lightweight,low-cost printing and commun-cations terminal. The LEX 21 ter-minal features a built-in modem,keyboard, and a thermal printerthat displays upper- and lower-case characters. It measures 22 by28 by 7.1 cm (8'/2 by 11 by 2%inches), weighs 2.25 kg (5pounds), and takes up half a stan-dard briefcase. Two K bytes of

memory and a 1 K-byte line bufferare standard. The selectabletransmission rates are 10 or 30characters per second. The LEX21 is designed for business andprofessional people for use in of-fices, homes, and when traveling.The LEX 21 costs S1195. ContactLexicon Corporation, 8355 Exe-cutive Center Dr, Miami FL

33166, (305) 592-4404.Circle 596 on inquiry card.

CBM 8032Color Computer

The CBM 8032 microcomputernow has color. The Color 8032features a 12-inch, 80-characterby 25-line video display, 73-keyupper- and lowercase keyboard,and numeric keypad. It also fea-tures a high-resolution RGB (red/green/blue) color monitor that dis-plays eight colors in the text andgraphics modes.

CBM 8032 software runs on theColor Computer without modifi-cation. Using the Control key,users can change foreground andbackground color combinations,or use reverse field for high-lighting. In the graphics mode,the Color Computer provides 160by 100 dot resolution. The com-puter contains a 32 K-byte screenedit ROM that provides color-han-dling capability. The CBM version4.0 BASIC interpreter remains un-changed. Contact CommodoreBusiness Machines Inc, 681Moore Rd, King of Prussia PA19406, (215) 337-7100.

Circle 597 on inquiry card.

484 October 1981 © BYTE Publications Inc

Best prices anywhere INow a Toil-Free "800"

COMPUTERS

YtNiTH I data

I systems

Z-89.... List

$2895

OUR PRICE

$2229

SUPERBRAIN

BvlNTERTEC

a

64KDD $2695

64K QD $2995

DSS-10MEG $3195

INTERTUBE $725

Emulator $725

CROMEMCO

CS2, List $4695.CS3, List $7995.

our price $3679our price $6349

NORTH STAR

HORIZON II

HRZ-2-32DD,List $3695 $2879

HRZ-2-64DD, List $4195 $3269

HRZ-2-Q32, List $3995 $3115

HRZ-2Q64, List $4495 $3505

Intersystems CALL FOR PRICES

TERMINALS

TeleVideo

Televideo 910 $579

912C $679

920C $779

950 $979

SOROC

■

Soroc IQ120 $689

IQ130 $579

10.135 $719

IQ135w/g $789

IQ140 $1049

1420.1500.1510.

HAZELTINE

.CALL.CALL.CALL

ZENITH

Z19

$719

PRINTERS

CENTRONICS

739-1

739-3

704-11 parallel........... .......

709-9

TI810

. $749. $799$1569$1519

810 Basic

810 Full Option.820 RO Basic..820 KSR Basic.

NEC 7510.7520.

$1289.$1599. $1545. $1739

CALLCALL

Diablo 630 $2049

PaperTiger460 $799

460G $843

560G $1099

Epson CALL FOR PRICES

DISKSYSTEMS

MORROW

Discus 2D $849

Dual Discus 2D $1389

2 + 2 $1199

M-26 $3599

M-10 $2999

Most items in stock tor immediate deliver/ Factory sealed cartons.w/fjll factory warranty. NYS residents add appropriate sales laxPrices do not include shipping VISA and Master Charge add 3%COO orders require 25% deposit Prices sub|ect to change withoutnotice

COMPUTERS WHOLESALE

P.O. Box 144 Camillus, N.Y. 13031

VISA

InN.Y.call 315472-2582

Circle 94 on inquiry card.

BYTE October 1981

485

What's New?

SYSTEMS

Multiuser System

The System/48 is a multiusersystem for small- to medium-sizebusinesses. It can accommodateup to eight simultaneous usersand has 20 megabytes of Win-chester hard-disk storage.

MAGIC is an operating systemfor the System/48. It provides ameans for direct-indexed accessto several billion bytes of storage.The DataMagic II is a data-basesystem that provides a screenformatter, the BASIC language, areport generator, and an edit, up-date, and query processor pack-age. For complete details, con-tact TEI Inc, 5075 S Loop E, Hous-ton TX 77033, (713) 738-2300.

Circle 598 on inquiry card.

Single-Board 8085 Computer

CPU-! is an 8085-based micro-computer similar to the Intel 80/04board. It is designed specificallyfor dedicated control applica-tions. The system operates at 3MHz and includes 256 bytes ofprogrammable memory, 22 I/O(input/output) lines, one serial I/Oport, one programmable counter/timer, and two sockets for 1 to4 K bytes of EPROM (erasableprogrammable read-only mem-ory). Only an external transfor-

mer is needed to complete thesystem. A printed-circuit boardarea is provided for user develop-ment. Applications programs forCPU-) can be developed usingany 8080/8085 developmentsystem.

The price for CPU-1 is S 185. Anexpanded version with morememory and I/O lines costs S220.Contact Pragmatic Designs Inc,950 Benicia Ave, Sunnyvale CA94086, (408) 736-8670.Circle 599 on inquiry card.

Econet Network

The Econet network system forinterconnecting computers andperipherals uses a four-wire con-nector. It allows a separation ofup to 1 kilometer between sta-tions and is compatible with allAcorn (or other microcomputer)systems. A ten-station networkwith a 400 K-byte file stationcosts £3000 (approximately$6000); additional stations cost£50 (about S100). Up to 255 sta-tions can be interconnected witha data transfer rate of up to210,000 bps (bits per second).Collision-detect circuitry and acollision-arbitration algorithmminimize the need for retries.Econet hardware fits inside acomputer, and the software re-sides in 4 K bytes of ROM (read-only memory).

Econet was primarily designedfor schools and institutions, but itcan be used in any environment.For more information, contactAcorn Computer Ltd, 4a MarketHill, Cambridge, CB2 3NJ,

England. Circle 600 on inquiry card.

486 October 1981 © BYTE Publications Inc

PRIORITY ONE ELECTRONICS

MICROPOLIS" S-100 DISC DRIVE SUB SYSTEMS

315KBYTES PER SIDE ON W OF COURSE! Micropolis, the world'slargest manufacturer of high density 5 '/<" disk drives, has been doing itlor years. And reliably at thai

An ordinary 5W floppy provides just 35 tracks per side and storesonly 70K bytes. This is not nearly enough for anything useful, soMicropolis uses 77 tracks per side. Each track is then formatted with 16sectors (hard) at 256 bytes per sector, yielding an impressive 315Kbytes per side.

Micropolis drives have a larger capacity than many 8" disk drives,though they only occupy the space of a 5W floppy. The 315K bytecapacity is roughly 4 times the capacity of a standard 5%" drive. This iswhat we call QUAD DENSITY.

To achieve the high density capability, you may think Micropolis hadto sacrifice speed or reliability. NOT SO! The track to track access time isonly 30ms with a high speed data transfer rate of 250.000 bits persecond.

By creating this high density format Micropolis is able to keep yourintial subsystem costs to a minimum. Your cost is less than $.002 perbyte. That's a BIG VALUE in a small package.

Reference Polnl tar

Petitioning or R/W Head

Thnjil BearingSplndli

4-ptlaM*—StapporLoad Scraw Motor

(Loading Laad Scraw AgalniiRataronca In Spindle Homing]

MICROPOLIS disk subsystems are expandable to keep up with yourever increasing needs. Uptofourdrives/headsmaybedaisy-chainedonone S-100 controller board. With all four drives/heads in operation, youhave access to over 1.2 MEGABYTES of on-line storage.

WITH MICROPOLIS, complete means COMPLETE. Each subsystemcomes complete with controller interface, cable, and software. Thesoftware includes the MDOS operating system, extended basic,assembler and editor. MDOS is a complete package, including anassembler, editor, file management functions and utilities, whichprovides total support BASIC is a self-contained package whichprovides a powerful set of tools for developing, testing, executing, andmaintaining BASIC programs.

BASIC is designed for microcomputers with at least 24K bytes ofRam ana MicropoHs' Mely-Huppy uisk system, tros can be useo atonein a 16K byte memory system.

Activating the built-in Auto load ROM brings up the system undercontrol fo the DOS executive. Basic can be accessed by issuing a simpleDOS command.

Both packages are designed for flexible, efficient programming. Bothpackages use the same file structure and file management scheme fortotal compatibility. Programs created under DOS can be loaded andaccessed from BASIC. Data files created under BASIC can be processedby user written application programs running under the DOS. Everythingyou need to get "On Line" in one complete package.

MICROPOLIS provides total integration, which means they controleverything from beginning to end. The result is a better drive for you,backed by a lull 120 days factory warranty.

Anyone can cut price by lowering capacity or eliminating valuablefeatures. But there's no long term advantage in it Not for the user. Or themanufacturer.

MICROPOLIS takes a better approach, even though it's more difficult.by using advanced design to provide more capability while lowering cost

PRIORITY ONE ELECTRONICS

9161 DEERINGAVE. ■ CHATSWORTH, CA 91311ORDER TOLL FREE (800) 423-5922 CA, AK, HI CALL (213) 709-5464

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 SHIPPINGS HANDLING of $2 50 for the (iist3 lbs. plus 25« 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. Credit Card orders will be charged appropriate freight

MICROPOLIS has a reputation for getting along with most everybody,Compatibility is not a problem with MICROPOLIS. Their disk drives and/or subsystems can be easily integrated into systems such asPolymorphic, Cromemco, CCS, Ithaca Inlersystems, Godboul Norihstar.Jade, Big Z, QT SBC 2/4, and many others. Many OEM manufacturersrely on MICROPOLIS to get the job done efficiently. In fact, to date theyhave delivered over 200,000 double track density drives, more than all oltheir competitors combined. Companies like Commodore, Exidy, Harrisand Vector Graphic, to name just a few. Years from now, you can lookback with a secure feeling knowing you made the best choice:MICROPOLIS.

For example, most 5'/'" tloppy disks cut costs by using a lessexpensive, less accurate plastic cam or cam follower to position theread/write head. Most 8 inch floppy disks use a better approach, with arolled steel lead screw for this function.

Disk drivis belai aaaaaitM lar aillvary ta Prhtrlty Om EkKiraalca.

As the world's largest distributor of MICROPOLIS SUBSYSTEMS,PRIORITY ONE ELECTRONICS is able to buy MICROPOLISdisk drives by the thousands and receive special pricing. That specialpricing we receive is passed on to you in the form of tremendously dis-counted prices.

MlCMraut kaa • initial ilik caatarlai »ackaalaai wkaraln tktctaiir al tka «ltk fits avar a pralllai aplaala ma la claaiaaO lataplace aklla Ika spinalis ratalaa la aaalat caatarlai.

MICROPOLIS goes them one better and uses an all-steel system,with a precision-ground steel lead screw and steel follower. II costs morebut gives you greater storage capacity with lower cost per thousandbytes. Not so incidentally, the steel construction (compared to plastic)significantly increases reliability, too. There's even a built-in File Protectfeature that prevents accidental loss of valuable data. (A file protected

diskette ja1"'"1 hf written nn

SELECT-, (-FILE PROTECT

MICROPOLIS

S-100 SUE-SYSTEMS

CAPACITY

DRIVES/

LIST

MODEL

(KBYTES!

HEADS/DRIVE

ENCLOSURE

PRICE

SHI PUT.

IHACKS/UISKtllk

PUWfcHSUPPLY

OuTT PRICE

MCP1053M2

630

1

2

$1534.00

30 lbs.

77/100TPI

Yes

$000.00

MCP1003H4

1260

a

2

$1688,00

30 lbs.

154/100TPI

Yes

$1395.00

MCP1043M2

150

1

1

$939.00

15 lbs.

77/100TPI

Yes

IIH.H

NCP1043M4

630

2

1

$1107.00

15 lbs.

154/100TPI

Yes

$•50.00

RCP1D41MI

315

1

1

$838.00

15 lbs.

77/100TPI

No

$640.00

MCP1041M4

630

2

1

$1005.00

15 lbs.

154/100TPI

No

$700.00

ADDRESS

Bay a ObM rirtvs HalBFIaasyaaa aaalkaiiiat. ■Us aar aallt-la LEDtkat laalaathr laalcalaa tka erlv. aslactaO, Orlve aMraea, aaO FllaPraljet

Heat can cause numerous read and write errors that can becomehazardous to your data. The major heat producing power supplycomponents are mounted to a large heat sink external to the cabinet, bythe power switch and fuse (located at the rear of the cabinet). This designis to assure that the drive components are kept as cool as possible toassure reliable data recovery

COMPLETE W/S-100 CONTROLLER, CABLES,MANUALS AND MICROPOLIS MDOS AND BASIC

ADD-ON DRIVES

MCP1033M2

30 lbs.■CPI033M4

30 lbs.MCP1023H2

15 lbs.MCP10Z3H4

15 lbs.MCP102IM2

MCP10I1M4

NOTE: Add-on modules do not include Controller, User's Manual or Diskettes

1

2

$1301.00

77/100TPI

Yes

$000.00

2

2

$1638.00

154/100TPI1

Yes

1

$1100.00

$689.00

77/100TPI

Yes

$400.00

2

1

$855.00

154/100TPI1

Yes1

$040.00

$586.00

77/100TPI

No

$430.00

2

1

$754.00

154/100TPI

No

$000.00

ACCESSORIES

Regulator kit lor 1041.1021.1015 and

Regi101

The temperature compensation loop in a MICROPOLIS drive includesonly the disk, preloaded leadscrew and spindle housing. The baseplate isspecifically excluded since its expansion is compensated by a propor-tional change in the preload of the leadscrew.

■CP1002-0I Relocatable bootstrap kit

■CP 1003-032 Poly 88 kit (relocated BASIC MOOS 4.0A)

MANUALS

MCPI004-01 Uaar'a Baaaal far ■Icrapalla 3-100

baa ayataai. Describes operation, con-figuring, installation of systems; explainsdetails ol our Disk Extended BASIC andDOS, and discusses diskette program-ming in general. 5 lbs. (Included with allsubsystems)

■CP1004-02 Halataaaacs «aasal for all Micropolis

floppy disk drives

DISKETTES, ETC

MOO.M7M0 77 Track Cert Single Side, Box 10VMM0007-10 77 Track Oert. Double Side, Box 10VRBFD05 5W Head Cleaning Kit

OEM I DEALER INIUIRIES INVITED

$20.00

125.00$25.00

$00.00

$00.00

$40.00$00.00$20.00

Circle 417 on Inquiry card.

Circle 243 on inquiry card.

*„ »

1100

2032 32K STATIC RAM A & T.

450 NSEC ..$579.00,300 NSEC...$5B5.00.200 NSEC...$629.00

2116 16K STATIC RAM A & T.

450 NSEC...$285D0,300 NSEC...S289.00,200 NSEC...$329.00

2065 64K DYNAMIC RAM A & T $548.95

2200 S-100 MAIN FRAM A&T $379.95

2422 FLOPPY DISC WITH CP/M 2.2" $329.95

2102 6502 PROCESSOR A&T $282.95

21I0A Z80 CPU A & T $249.95

2710* 4 SERIAL 1/0 A & T $291.95

2718A 2 SERIAL, 2 PARALLEL A&T $305.95

2720A 4 PARALLEL A&T $214.95

PHOTO BOARDS WW .... $39.95, SOLDERTAIL .... $29.95

APPLE PRODUCTS

7I14A 12K ROM/PROM $68.50

7424A CALENDAR/CLOCK $106.95

7440A PROGRAMMABLE TIMER $98.50

7470A A TO 0 CONVERTER $105.95

7400A GPIB (IE 488) INTERFACE $265.95

7710AASYNC SERIAL $125.95

77I2A SYNC SERIAL $153.95

7720A PARALLEL STANDARD $98.95

7720B PARALLEL CENTRONICS $98.95

7811B ARITHMETIC PROCESSOR W/OISC $342.95

7SI1C ARITHMETIC PROCESSOR W/ROM $342.95

7500A WW BOARD $22.95

75I0A SOLDERTAtt BOARD $23.95

SOFTWARE

2610 CP/M'"MACRO ASSEMBLER ON DISK $76.95

2620 CP/M™SYM BOLIC INSTRUCTION DEBUGGER... $64.25

2630 CP/M™TEXT FORMATER $64.25

2640 CP/M'" BACKGROUND PRINT UTILITY $42.95

OTHER CCS PRODUCTS ARE AVAILABLE.CALL FOR PRICE.

£JFtD *

ICROCOMPUTER PRODUCTS

S100 PRODUCTS

C6IA 8080 PROCESSOR PCBD $32.95

KIT $155.95, A&T $215.95

CB-2 280 PROCESSOR BOARD.

KIT $198.95, A&T $269.95

VBIC 64 x 16 VIDEO. PCBD $32.95

KIT $153.95, A&T $199.95

VB2 64 x 16 VIDEO, PCBD $32.95

KIT $175.95, A&T $234.95

VB3 80 CHARACTER VIDEO 4MHZ.

KIT $345.95, A&T $425.95

UPGRADE RAMS FOR VB-3 $42.00

104 2 PARALLEL 2 SERIAL PCBD $32.95

KIT $155.95, A&T $194.95

PB-I 2708, 2716 PROGRAMMER BOARD.

KIT $135.95, A&T $185.95

MB-IO 16K STATIC RAM.

KIT $299.95, A&T $339.95

APPLE PROUUCTS

A4BB IEEE 488 INTERFACE $399.95

AID SERIAL/PARALLEL INTERFACE.

KIT $125.95, A&T $155.95

ASIO SERIAL I/O

KIT $87.95, A&T $97.95

APIO PARALLEL 10

KIT(W/OCABLES)... $67.95. A&T(W/0CABLES)... $87.95

OTHER SSM PRODUCTS ARE AVAILABLE.CALL FOR PRICES.

WM

MONDAY-FRIDAY, 8:00 TO 12:00. 1.00TO5:30THURSDAYS, 8:00 TO 9:00 P.M.

(415)728-9121P.O. BOX 955 • EL GRANADA, CA 94018

PLEASE SEND FOR IC, XISTOR AND COMPUTER PARTS LIST

OCT. SPECIAL SALEON PREPAID ORDERS

(CHARGE CARDS AND C.O.D. OR PO HOT AVAILABLE DN THESE OFFERS)

APPLE SALE. 5% OFF OF CCS APPLE COMPUTERPRODUCTS.

W777C

inc. WAMECO INC.

BOARDS WITH MIKOS PARTS

HEM-3 32K STATIC RAM. PCBD $36.95

KIT LESS RAM $95.95, A&T $135.95

CPU-2 Z80 PROCESSOR, PCBD $32.95

KIT LESS ROM $109.95. A&T $149.95

EFM-2 16K/32K EPROM, PCBD $32.95

KIT LESS ROM $65.95, A&T $99.95

FPB-1 FRONT PANEL, PCBD .'. $48.50

KIT $144.95. A&T $184.95

CPU-1 8080 PROCESSOR, PCBD $29.95

KIT $89.95, A&T $129.95

0MB-I2 13 SLOT MOTHER BOARD, PCBD $39.95

KIT $95.95, A&T $135.95

OTHER WAMECO PRODUCTS ARE AVAILABLE.CALL FOR PRICES.

MIKOS PARTS ASSORTMENTS ARE ALL FACTORY MARKEO PARTS KITS INCLUDEALL PARTS LISTED AS REOUIRED FOR THE COMPLETE KIT LESS PARTS LISTEDALL SOCKETS INCLUDED.

LARGE SELECTION OF LS HI AVAILABLE.

PURCHASE $50.00 WORTH OF LS TTL AND GET 10% CREDITTOWARD ADDITIONAL PURCHASES. PREPAID ORDERS ONLY

VISA 01 MASTERCHARGE Send account number, interbank number, expiration (taleand sign your order. Approx postage will be added Check or money order will be sentpost paid in US It you are not a regular customet. please use chatge, cashier's check orposlal money order Otherwise there will be a two-week delay lot checks to clear Calilresidents add 6% tax. Money back 30-day guarantee We cannot accept returned IC'sthat have been saldeted to Prices subject to change without notice Jl 0 Hlilaia inlir.S1.50 linrltl ckllfl 11 oriiri III! till X10 00-

CALL TOLL FREE

1800228 4097

Call For "Unbelievable" Low Low Prices AOn These Lines:

^#

AMDEK

APPLE

ATARI

BASE 2

CENTRONICS

COMMODORE

DC HAYES

HAZELTINE

LEEDEX

MACROTRONICS

MAXELL

MICROSOFT

MOUNTAIN'HARDWARE

N.E.C.

NORTHSTAR

PANASONIC

SANYO

SYNCOM

488 BYTE October 1981

youft

EliCTftONICS PlAXGftOUND

1840 "O" Street Lincoln, Nebraska 68508In Nebraska Call (402) 476-7331

Circle 143 on inquiry card.

INCREDIBLE? believe

PRINTERS

150 cps bidirectional-9x9 dot matrix, quietizedcase, 136 col, vertical form control and manyother functions $11 OR

We feel this printer offers * I I SKI

the best price/performance ratio available.RS-232 serial to 19,200 baud x-on, x-off add S40

rrgn Teletype 40,300 LPM-typewriter quality, RS- from Only

* '" 232 interface. This quality printer is available in many $2928configurations including forms access, quietized case, etc.Teletype 43 from $995

Qdntex 6000

paper

Teletype AP-200, 340 cps dot matrix (similar to Data Prod.

NEC Spinwriter-55 cps, bidirectional, letter qualityR.O. $2560 KSR

DIABLO 630-40 cps, bidirectional, daisy wheel, plot/graph

QUME Sprint 9/45 cps, daisy wheel

C. ITOH Starwriter, 25 cps, daisy wheel

C. ITOH Starwriter, 45 cps, daisy wheel

EPSON MX-80, 80 cps, 9x9 dot matrix

ANADEX 9500/9501, up to 200 cps, high resolution dot

OKIDATA Microline 80, 80 cps, 9x7 dot matrix

Microllne 82, bidirectional, friction/pin feedMicroline 83, bidirectional, 120 cps, uses 15

TI-810,150 cps, Basic

Package-Compressed print, vertical form control

CENTRONICS 704-9,180 cps, 9x9 dot matrix, 132 col, RS-232704-11,180 cps, 9x9 dot matrix, 132 col. parallel730,100 cps, 7x7 dot matrix, sameasR.S. LPII739100cps, nx9 dot matrix,

DEC LA-34

IDS460G

S-100 SPECIALTIES

DP/Z-80A, CPU, 64K ram, floppycont., RS-232 port.SlOO IEEE, 8 slotin Adds terminal, inc. CP/M 2.2 $CALL

M-200) $2799

$2799

$2449

$2226

$1575

$1849

SCALL

$1349

$490

$599

$875

$1449

$1630

$1595

$1695

$660

$849

$1085

$692

'ASMPi

®.®

22002065C2810A2422A

8"SHUGARTSA851R

$669 2 for$1289

$625 2 for $1199

$299

$445

$950

$1195

8" DISK DRIVE SALE

8"SHUGARTSA801R $450QUME DATATRACK 8

Enclosure, power supply for 2 8" drives A&TNNC industrial grade enclosure for 2 drives with PSMORROW Discus 2D + CP/M® , MICROSOFT BASICDiscus 2+ 2 +CP/M® , MICROSOFT BASIC

HARD DISK SPECIALS

CORVUS10MB and controller

20MB and controllerConstellation Network Multiplexer and Mirror Video Tape Disk BackupMORROW 26MB +controller + CP/M 2.2®, M basic $4495 $3821

t>AUl0 controller, CDC Hawk Drive (5 fix, 5 rem) $6995 $5995

controller, Western Dynex (5 fix, 5 rem) $5995 $5099

fl^ Winchester 5Vi drives complete with case, cable,

Mljl software, S-100 controller. Adapter avail, for use with

^IXCOMP any Z-80 system. Cartridge drive controllers avail

Quantity discounts available!

List$5350$6450

onlyScall

Scall

5MB10MB

List$2898$3398

nn

Delta has Winchester based networks of up to 16 users available.

n^2HGr°i,p ("'a" us for tiest pnces on thesfi h!gh

•"•■"■'••'■' r*-i generation boards and systems. .

■■■ California These high quality, reliable products have made CCSQS. computer defacto industry standard for S-100 products^J Systems Assembled and tested: list only

H.D. Mainframe, 20 a. P.S., 12 slot MB $434 $359

64K dynamic RAM/Bank Select $720 $580

Z-80 CPU, serial port, ROM monitor $310 $259

Floppy Cont, CP/M 2.2, ROM monitor $425 $345

, 8000 DT—w/64k. 1.2 MB8" floppies, 2 serial, 3 par. CPM 2.2 $CALLFULL 2 YEAR WARRANTY!

Z-80 CPU $310

D2 Disk controller $354

bv« 64K Dynamic Ram $648

/HICROBYTE FULL SYSTEMS AVAILABLE

SUPERBRAIN Scall

Similar savings on the full lines of CCS, SSM, NNC, MORROW, DELTA,NORTHSTAR, ITHACA INTERSYSTEMS, GODBOUT, NEC. TELEVIDEO, IMSZENITH, ADDS, DEC, DATA GEN., ATARI, DYNABYTE.

S33-33MB Drive and Controller $4468

S66-66 MB Drive and Controller $5925

PRIAM 8" and 14" Winchester/tape subsystems avail.We carry the full line of ADES 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 64K bytes

RAM, Z-80A 4mh CPU. We offer a full line of quality, tested software.

Delta TVD w/1.2 Mb floppy drives, 2 serial, 3 parallel ports $CALL

Delta 1004 w/10 MB hand disk.1 MB floppy, 6 serial, 3 parallel ports $CALL

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

NNC 80 w/1 MB floppy drives, 2 serial, 3 parallel ports $3799

NNC 80W W/.5MB floppy, 8.4MB hard disc, (OASIS optional) $6693

ALTOS single and multi-user systems Scall

MORROW Decision 1, MICROSOFT basic, UNIX Scall

VFRPIX 820 Desktop computer-64K, 2 floppys, (CP/M AVAIL.)/\i_i \w/\, Lis, $2g95 $CALL

We offer multi-user networks by DELTA, DISCOVERY, TELEVIDEO, MUSYS,IMS, DIGITAL, MICRO.

TERMINALS

AMPEX DIALOGUE30, 80 SCALL

TELEVIDEO 910 C (multi-terminal) $699 $599

920C $1030 $789

950C

SOR0CIQ120

HAZELTINE ESPRIT

DECVT-100

Similar savings for our HAZELTINE and LEAR SIEGLER lines

LOOK HERE! A'Y,PE„^

Call us for ALL your softwear needs Dialogue 80

SYSTEMS HOUSES & EDUCATIONAL INSTITUTIONSGIVEN SPECIAL CONSIDERATION.

$1195

$989

$995

$729

$745$2050

$669$1575

ALL OF OUR PERIPHERALS CAN BE CONFIGURED FOR RADIO SHACK® MODEL II

DEALER and INTERNATIONAL INQUIRIES WELCOME

WASHINGTON COMPUTER SERVICES

an affiliate of (//WASHINGTON))) est. 1912w ELECTRIC COflftPrtNY'"

INCORPORATED

CUSTOM COMPUTER ROOM WIRING SINCE 1960

97 Spring Street

New York, N.Y. 10012

Hours: 8AM-5:30PM (EST)Mon.-Fri.

TO ORDER: CALL OUR TOLL-FREE NUMBER:• (800) 221 -5416 • In N.Y. State and fortechnical information call 1 -(212) 226-2121

For fast delivery, send certified checks, money order orcall to arrange direct bank wire transfers. Personal orcompany checks require two to three weeks to clear. Allprices are mail order only. Prices subject to changewithout notice; call for latest prices. Prices include 2%cash discount. N.Y. residents add sales tax.Quantex is a trademark of North Atlantic Industries, Inc.Radio Shack® is a trademark of the Tandy Corp. ■^P'CP/M» is a trademark of Digital Research mhm

Circle 390 on inquiry card.

BYTE October 1981

489

Circle 138 on inquiry card.

FLOPPY DISK DRIVES

Qume Datatrak-8 $540

Virtually the industry standard. High quality/reliabil-ity. Full featured, double-sided, double density.

SA851R $540

Full featured drive, double sided, double density

$A801R $430

Single sided, double density, very consistent

FDD100-8 $430

Qume Datatrak 5 5%" $345

SA-400 5V«" $299

TandonTM-100 48TPI 5V4" $350 96 TPI $425

We are expecting a large shipment of mini's, many types. Call for details.

CONTROLLERS

Tarbell single density kit $195

Tarbell single density A & T $310

Tarbell double density A & T $425

CCS 2422 w/CPM 2.2 $350

Godbout Disk 1 $450

MDA MXV-21 LSI-11 controller

(RX-01, RX-02 compatible)

$1050

MISCELLANEOUS

CCS Mainframe $395

2 Disk drive enclosure $ 95

(fits Siemens, Shugart, Qume)CP-206 power supply $110

(powers two floppies)

Cable Kits 2 drives $ 35

3 drives $ 40

4 drives $ 45

Diskettes ss $39/10 - ds $59/10

CPU

CCS 2810

Godbout Z-80A .Godbout 8085A .

$ 275S 275$ 295

MEMORY

CCS 2065 64K dynamic.CCS2116 32K static . . .Godbout RAM 17 64K .

$ 625$ 675$ 995

I/O

CCS2710 4SIOGodbout Interfacer 1Godbout Interfacer 2

$ 325S 225S 225

Qume S/5 - Daisy Wheel Printer

Sprint 5/45 RO

Sprint 5/55 RO

Sprint 5/45 KSR

Sprint 5/55 KSR

Forms Tractor

Pinfeed platen

Paper Guide

Paper Basket

many print wheels, ribbons, & more available.

$2699

2829

3029

3159

210

155

30

50

Terms of sale: cash or checks, purchase orders from qualified firms and institutions. Minimum order $25. CA residents add 6% tax. Pricessubject to change without notice. All goods subject to prior sale. Minumum shipping/handling charge $4.00.

Electrolabs

POB 1608, Palo Alto, CA 94302 (415) 321-5601

CALL TOLL FREE:1-800-547-2092

topplG 1 6H

VISA'

+

New rfi version

48H+

New RFI Version with Aoole memory

$1029$1079

in Aoole memory

ATARI A 400 (16M $329

800(1610 $739

Toll free number for order desk only. In Oregon and for service orwarranties call (503) 479-4150. Bank wires, cashiers checks and bankcardsaccepted immediately. Allow 10 days for personal checks. Master Chargeand VISA add 2%, sorry no C.O.D.'s. Add 2% {minimum $4.00) for allU.P.S. shipments to cover freight, handling and insurance. $100.00minimum order. Prices subject to change without notice. NOTE: Weare registered with the State of Oregon, have been in electronic sales andservice for 5 ye^rs and are fully qualified for repair of any micro computersystem. Three full-time certified technicians insure one-day turnaroundon most Apple repairs.

"A Unique Combination olQuality Products. Competitiue Prices, and Seruice"

APPLE HARDWARE

ATARI HARDWARE

DISK DRIVE w/33

CX-2600 VIDEO GAME

'149

CONTROLLER

1499

410 PROGRAM RECORDER

'59

DISK DRIVE ONI V

'429

810 DISK DRIVE

'429

SILENTVPE PRINTER

820 PAINTER

•319

w/INTERFACE

>349

820 PRINTER

'249

GRAPHICS TABLET

'599

822 PRINTER

'339

APPLE SOFT OR INTEGER

825 PRINTER

'569

CARD

'139

830 MODEM

'149

PASCAL LANGUAGE CARD

>369

850 INTERFACE MODULE

'139

PARALLEL PRINTER CARD

'129

853 16K MEMORY EXPANSION

'89

SERIAL PRINTER CARD

'159

CENTRONICS PRINTER CARD

>149

SOFTWARE

LOWER CASE ADAPTOR

'39

16K RAM CARD (MICROSOFT)'159

VISICALL (ARARI)

'139

Z-80 CARD (MICROSOFT)

'329

BASIC (ATARI)

>49

MICROMODEM (HAYES)

'279

VISICALL

'139

SMART MODEM (HAYES)

1229

VISIDEX

'139

MOUNTAIN CLOCK

'249

VISIPLOT

•129

MOUNTAIN MUSIC SYSTEM

'479

VISITERM

'109

MOUNTAIN A/D CONVERTER

'299

VISITREND

'179

MOUNTAIN INTROL/X-10

D.O.S. TOOL KIT

'59

CONTROL

'179

D.O.S. 3.3 UPDATE

'49

MOUNTAIN C.P.S.

MICROLAB DATA FACTORY

'129

MULTIFUNCTION

'239

D B MASTER (STONEWARE)

'179

10 KEYPAD (A.B.T.)

•129

APPLE WRITER

'59

SUP-R-TERM (80 COLO

SUP-R-TEXT II

'109

BY M&R)

'299

WORDSTAR

'279

SUP-R-MOD (MODULATOR

B.P.I. FOSTWARE (each)

'319

BY M&R)

'22

GENERAL BUSINESS

16K MEMORY EXPANSION

'49

CONTROLLER

'509

JOYSTICK (T.G. OR

SOFT-TECH PAYROLL

'179

PROGRAMMA)

149

STOCKPILE INVENTORY

'369

9" B&W MONITOR (SANYO)

'145

ADVENTURE

'29

9" B&W MONITOR (N.E.C.)

•149

ZOAK

'29

12" B&W MONITOR (SANYO)

•189

SARGON CHESS

'29

12" GREEN MONITOR

GALAXIAN

'22

(SANYO)

'229

CALl FOR OTHER HARDWARE AND SOJUVARE

13" COLOR MONITOR (T.I.)

'319

IDS. 445C PRINTER

'689

IDS. 560G PRINTER

'999

Vta p^x

EPSON MX-80 PRINTER

'479

^EH^E^^

EPSON MX-100 PRINTER

'829

H|

H

EPSON CABLE AND INTERFACE '89

^l^tal

N.E.C. SPINWRITER PRINTERQUME 5/45 PRINTERTEXAS INSTRUMENT 99/4

'2499

v—""^

*

'399

530 N.E. 'E' Street • Grants Pass, Ore. 97526

490 BYTE October 1981

Circle 323 on inquiry card.

SERIOUS S-100 USERS:

We configure to your needs.Multi-user, multiprocessor,hard disk, tape backup, al-ternative DOS'—we have theright product at the rightprice.

<\

QT

SYSTEM+

fl

• 4 MHZ Z-80A, 2 serial, 2 parallel

• 2 8" floppies, double density

• 64K Ram. EPHOM monitor for RS-232

• CP/M 2.2

• Optional 6, 8 or 12 slot motherboard

• Optional single or double-sided floppies

• Burned in—just add video terminalSYS*SS(6)... $3415 SYS*DS(6)... $4270SYS-SS(8) .... 3510 SYS*DS(8).... 4365SYS»SS(12)... 3605 SYS*DS(12) ..4460

f5fc

QT

MINI-SYSTEM+

MINI-SYSTEM* (5S4)

• Above with 5'/." floppies

MSYS*SS(6) . $2745 MSYS»DS(6). $3045

MSYS*SS(8) .. 2845 MSYS*DS(8).. 3145

MSYS*SS(12) . 2945 MSYS*DS(12). 3245

V,

QT

DISK

PACKAGES

DDC-88-2 2-801R. cab., ps. fan ... $1225DDC-88-22 2-Qume DT-8,

cab., ps, fan 1625

DDC-88-3 Cabinet, ps. fan. cables... 300DDC-88-4 Cabinet only 60

QT MAINFRAMES

• 18A power supply, S-100

• Drive power supply

• Specify motherboard slots

• Specify 8". 5 V or no (loppy2-8" Floppy w/motherboard

MF8-6 $600

MF8-8 625

Mf8-12 650

2-5%" Floppy—w/motherboard

MF5-6 $425

MF5-12 475

No Floppy—w/motherboard

MF«12 $425

MF+18 475

MF*22 575

QTSINGLE' CABINET

IE

• Accepts one 8" floppy

• Power supply, fan, AC filter

• 117v AC/220V AC

• Data cable, power cables

DDC*8 $165

QT S-100CARDCAGES

• 6, 8 or 12 slot

• Accepts Silence + mother

• With card guides

• Accepts 4" fan

• Specify with mother, with fan6 Slot (5%w x 10'Ad x 6"h)

CC*6 $24

CC*6M 85

CC*6M/F 110

8 Slot (7'/lw x 10V4d x 6"h)

CC»8 $37

CC*8M 95

CC»8M/F 130

12 Slot (11Viv» x 10'Ad x6"h)

CC«12 $60

CC*12M 110

CC+12M/F 145

QT SILENCE+S-100 Motherboards

• Full ground shield network

• Specify board, kit, or assembled

6-B $22 8-B $25 12-B .

6-K 38 8-K 52 12K..

6-A 47 8-A 65 12-A .

18-B $48 22-B

18-K 97 22-K

18-A 135 22-A

528. 67. 85

$73138185

QT SBC+2/4

Kit $190 A&T $290

QT Z+80 CPU

Kit $160 A8.T 215

QT EXPANDABLE+RAM

EXP*16 $265 EXP+48 $300

EXP*32 285 EXP«64 320

QT I/O+

Kit $260 A&T $365

QT CLOCK/CALENDAR+

S-100/Apple/TRS $140

ADESS-100HARDDISK

• PRIAM 8" and 14" Winchesters

• With S-100 controller. BIOS

• Cables, cabinet, power supply

• First # = hard disk MByte,second » = tape cartridge MByte

S10 $3275 S10/10 $6190

S34 5420 S34/20 8495

S33 4255 S33/20 7525

S66 5660 S66/20 8860

SIERRA DATA

S-100 Z80A/B

Single Board Computer

• CPU, 4 timers, 64K Ram

• 2 serial, 4 parallel, 16K Eprom

• Floppy controller, D-D

• Winchester interface

• Eprom programmer

• Specify 4 or 6 MHz, master or slave

4M $875 6M $1150

4S 775 6S 1050

Recommended DOS (CP/M compatible}Single $300 Multi-CPU .... $750

• 64K IC's. dynamic

• S-100. 4MHz

• Assembled and tested. 64K or 256K

B256-64 $470

B256-256 995

COMPUTER RESOURCES256K S-100 Dynamic Ram

• 8 MHz capable, 8 or 16 bit CPU

• Parity detect

• Full IEEE 696

• Assembled and tested, with 64K or 256K

CR256-64 5900

CR256-256 1300

SEALS IS BACKSeals 64K Static S-100

•Uses Fujitsu MB8167. 15K*1 static in20pin

• 70ns: DMA to 14MHz

• Complete 16 bit or 8 bit flexibility

• IEEE S-100 and Cromix compatible

List $1195 Now $1050

STATIC MEMORYSYSTEMS 64K Static S-100

• See ad, this issue

• Intermix RAM and EPROM

• 200ns, very low power

SMS-64K A&T $550

SEC PERSONAL

COMPUTERPC-8000 Family

• 80x24 display, hi-res color

• Upper and lower case Authorized

• Most popular in Japan Dealer

• Features compare with Apple IIISystem: CPU. I/O. Disks $2897

APPLE II+

48K $1175

TELEVIDEO

950C $975

920C 745

ADDS VIEWPOINT 625

XYMECHY-Q 1000

DakywhMl Printer/Typewriter

• Bold, underline, reverse, right justify, center

• 10, 12 and 15 pitch

• Automatic error correction

• 15 character display

• Fast, nationwide serviceSAVE $400

Parallel $2450

RS-232 2675

IEEE-488 (GPIB) 2525

Tractor 325

800-421-5150

STARWRITER.

SiS'Ilii!

• Daisywheel printer,Diablo compatible

• Nationwide service

• Centronics parallel or RS-232 serial

• 25 cps or 45 cps, specify

25-P $1400 25-S $1500

45-P 1750 45-S 1850

Tractor S200

IDS PAPER TIGERS

H445 $ 710

S460G 1050

#560G 1300

EPSON MX-80

$500

Friction upgrade 60

For Apple parallel w/cable 110

EPSON MX-100

• Wide carriage

• Friction, tractor, graphics

• "Correspondence" quality printUnbeatable price $795

FOR APPLE

2 MBYTE

FLOPPY

FOR APPLE

• 2 double density, double sided 8" drives

• Cabinet, power supply, cable, controller

• DOS 3.3 compatible (Pascal and CP/Moptional).

• This package is best, spec for spec,price for price.

Sugg. List.... $2550 Now Only .... $2050SAVE $500CP/M Patch $75 Pascal Patch $75

16K Ram card $85

64K Ram card 345

Add-on mini (loppy 375

DISK DRIVES

801R $410 B51 $250

DT-8 585 B52 320

850R 610 B91 320

FDD120-8 375 B92 430

MICROPOLIS 8"HARD DISKS,with controller

#1221 9MB $2475

#1222 27MB 3014

#1223 45MB 3604

Floppy-Data:Card Edge

Type SD • Jade

DSC-34-1 Single, mini $24

DSC-34-2 Dual, Mini 29

DSC-34-4 Quad, Mini 34

DSC-50-1 Single, 8" 24

DSC-50-2 Dual. 8" 32

DSC-50-4 Quad, B" 40

SD |

SYSTEMS ^3tr

MULTI-USER BOARD SET

38062 SBC-200 (RS-232) $ 471

38059 Versafloppy II (RS-232) 500

38023 Expando RAM II-64K (2 pes.) . 1400

38032 MPC-4....4 port serial 764

39039 COSMOS (CP/M compatible) ., 350

List $3465

Qume DT-8 (1 pc.) N/C

CBASIC II N/C

Package of the year award ... $3485

All SD items available.

38007 Z-80 Starter Board $424

38013 VDB-8024 (60 Hz) 444

38020 Expandoram II-16K 310

38023 Expandoram II-64K 370

38025 PROM 100 248

38059 Versafloppy II (RS-232) 400

38060 Versafloppy II (VDB-8024) 400

38061 SBC-200 (VDB-8024) 376

38062 SBC-200 (RS-232) 376

Call for kit, software, and cable prices.

CALIFORNIA

COMPUTER

SYSTEMS

15% DISCOUNT

All CCS items available.S-100

2032A 32K Static - 2 MHz $561

2032B 32K Static - 4 MHz 641

2116A 16K Static- 2 MHz 297

2116B 16K Static -4 MHz 331

2200A Mainframe 368

2210A System 1825

2422A Floppy Controller 360

2710A 4-Port Serial 289

2718A Serial/Parallel 306

2720A 4-port Parallel 212

2810A Z80 CPU 263

TELETEK

FDC-1 Single Board Computer $685

FDC-2 Double Density Controller 325

INTEGRATED CIRCUITS

4116 (200ns) ..$2.002114 (450ns) ...2.00

2708 3.50

2716 (5V) 6.50

2716 (5-12V) ...8.00

2732 13.00

4164 (200ns) ..25.00

Z-80A 12.95

8080A 3.50

8085A 20.00

8086-4 60.00

TMS9900 29.95

8212 3.50

8214 4.50

8228 6.00

8238 6.00

8251 7.00

BULK DISKETTES

■ Single side, double density

• Specify hard, soft, # of sectors

• Sold in hundreds

8257 $17.95

8295 16.50

MC14411 11.00

14411Xtal 4.95

1771B01 24.95

1791A01 37.95

S2350 7.95

N8T26 2.50

1488 1.25

1489 1.25

D3242 10.15

TMS5501 19.00

TR1602B 4.50

6845P 22.00

4118 18.95

DP8304BN 4,00

WW....

... $215/100 8"

$275/100

Library

:ases:

ANTI-STATIC

CHAIR MAT

• 4'x5' black, hard

• With ground strap

•New re

ligion—thousands of believers

$160

CABLES

RS-232

male/male - 9 ft

$24

RS-232

male/male - 18 ft

29

RS-232

male/female - 9 ft

29

FLOPPY-DATA: PIN TYPECCS • Tarbell • Teletek

DSP-34-1 Single. Mini $24

DSP-34-2 Dual, Mini 29

DSP-34-4 Quad, Mini 34

DSP-50-1 Single, 8"..DSP-50-2 Dual, 8"DSP-50-4 Quad. 8" ..8" Floppy-DC PowerPDC-8 24" long...

242934

Apple is a trademark of Apple Computer, Inc. CP/M and MP/M are trademarks of Digital Research. TRS-80 is a trademark of Radio Shack.

MAIL ORDER: P.O. Box Q, Sherman Oaks, CA 91423RETAIL: 15618 S. Inglewood Ave., Lawndale, California 90260(213)970-1476 (800)421-5150 % Block South of San Diego Fwy.

TERMS OF SALES: Cash, checks, credit cards, C.O.D. Accounts available to education, government, andqualified businesses. Calif, residents add 6% sales tax. F.O.B. Lawndale, $3 minimum shipping and handling. J

Circle 43 on inquiry card.

wabash

When it comes to

Flexible Disks, nobody

does it better than

Wabash.

MasterCard, Visa Accepted.Call Free: (800)235-4137

PACIFICEXCHANGES

100 Foothill BlvdSan Luis Obispo. CA93401 (InCal call(805)543-1037)

EAGLES 'COWBOYS ■

RAIDERS ?RAMS ?

II you'd like lo know NOW before the Big gameWilh PROCAP and your TRS-BO". you can use statistics andprobability theory to predict the results ol this week's biggames And more. PROCAP

• Gives ollensive and defensive ratings lor everyNational Football League learn

• Predicis range ol results and probable score loreach game

• Allows computer malchup ol any Iwo teams(Great tor playolfs')

• Gives up-to-the-minute" standings, statistics.and ratings lor each NFL Division

PROCAP is easy to use ana comes with extensive documentationDisk or cassette version is only S49 95

srder

I our loll

NOW Money back

The Trinity Computer Group • Software Agent /Publisher

t~ QUARTZ CRYSTALS ~f

1 | 3218-0

5.242B-B

9.9336-B

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42151BB

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9.96960 B

22MB4-B 37962BB

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10499181 . 1

( ALL A -

J2S9

ALL B -1199

OORMflttf DEDUCTS ' 1

ADD SI.00 SHIPPING

CAL.

RES. ADD 6% SALES TAX

FREE OSCILLATOR SCHEMATICS

WITH ANY ORDER

11 QUALITY COMPUTER PARTS ])

1 P.O

BOX 743 / CHATSWORTH. CA 91311 »

Circle 288 on Inquiry card.

Circle 403 on inquiry card.

Circle 310 on inquiry card.

UV EPROM ERASER

$fl9.95

ERASES ALL UV ERASABLE EPROMS

(2708, 2716, 2532. 2564. eldQUICK FIFTEEN MINUTE ERASE TIMEERASES OVER FIFTEEN EPROMS AT A TIMELAMP LIFE. 7700 HOURSTIMER AND SAFETY INTERLOCK SWITCH OPTION

DEALER - INQUIRIES INVITED.

QUV-T8 49.95

Shipping 2.50

COD charges 1.50Timer & Switch

option 20.00

Deliv

/ app. 20 days

Send Check or COD order to:LOGICAL DEVICES, INC.

781 W. Oakland Park Blvd.

Ft. Lauderdale, Fla. 33311

(305) 97*1-0967

EPSON

DOT MATRIX PRINTERSSUPER DISCOUNTS ON

MX-80F/T ^ NOW

MX-80

MX-100 lo^ri STOCK

We also stock direct connect cables forTRS-80, Apple, Atari, Pet or RS 232

CALL TOLL FREE

-S69T

LOWER!

£4*9 I IV I

LOWER! UN

1 -800-344-7493

In CA and for service (209) 667-2888

©

GRAPHICS ROM'SAVAILABLE

/VWCROTRONtCSinc.. Ctt

'urlOCti C oMO"«cWbMO

FACTORY PRIME STATIC RAM CHIPS

2114 Super Low Power

200ns. 1Kx4 $ 2.90

6514 CMOS 300ns. 1 Kx4 $ 6.90

6116 CMOS 200ns. 2Kx8 $22.50

Add $5.00 Handling on Orders Under $200.00FAPTflHY PRIMP From trie same shipments used inTHPIunr mime GIMIX Prolessionalquallly wards

32KB STATIC RAM CARDS

for the SS50 and SS50C BUS

(16KB - $298.12), (24KB - 348.14)

(32KB - $396.15)

eW! 64KB BATTERY BACK UPN CMOS RAM CARDS

Two independently addressable 32KBblocks, each with extended addressing.

(56KB - $994.56), (64KB - S10BB.64)

2MHZ 6609 56KB SS50 SYSTEMS $2498.29

DISK SYSTEMS AVAILABLE

GimiX (51

1337 W. 37th Place • Chicago, IL 60609(312)927-5510 • TWX 910-221-4055The Company that delivers.

Quality Electronic products since 1975.

GIMIX" and GHOST" are Regislered Trademarks o! GIMIX INC.

Circle 202 on Inquiry card.

Circle 206 on Inquiry card.

Circle 159 on inquiry card.

ANALOG** I

ANALOG** DIGITALDIGITAL** ANALOG

CONVERSION MODULES

SOFTWARECAIN CONTROL

vrijilili.'f custom board test S-10D :■' m IS hh

nnvcr-.inn hrn<- mixabla high and lOLU inputs <

from 1 to 1024 IPUii ' iimpta nnd holri cvnp,.,™1 rhanntil ritfrctmnm tl 16 channel . tnnli ig la < totalnn(i n<nir(uu programmable gain instrumentationamplifier ruttnm IvvvcJ 1ml S IfK) 2 to 15 khzonverslon time mmM- rwjhnnd Iouj inrailoh. I i<. IOP/1 12 bit sample and hold i8-channel differential IA rhoi ini tl analog to digitalhigh accuracy pronriimmntitc mm in«.lrtrmRfitotion■ uiifiMn-r custom board tcl S-100 1' m !'■ kh/

1

For additional details about the AD-100-4 and otherfine California Data Corporation 100% individuallytested, high reliability products, circle the readerservice card number below or for faster responsewrite or call us.

CALIFORNIA DATACORPORATION

3475 Old Conejo Road, Suite C-10Newbury Park, CA 91320

(805) 498-3651

Circle 54 on Inquiry card.

floppy disks.

100% CERTIFIED AND TESTEDPREMIUM QUALITY

a BASF

Immediate off the shelf delivery.. .one box orquantity orders welcome.

SAVE to" 40%

CALL OUR ORDER DESK NOW!

(805) 985-9824

MASTERCARD — VISA — COD.

NATIONAL DATA SUPPLIES. INC.

Convert your TRS-80 into a

DEVELOPMENT SYSTEM

Z-80 In-Circuitemulation andEPROM/EEPROMprogramming ina single compactunit.

Circle 259 on Inquiry card.

Debug stand-alone .

systems with

program in

TRS-80 RAM,

then copy working program into PROM.

Only $329 including personality modulefor 2716,2516,2758,2508,2532,2816,2808,48016.

ORION INSTRUMENTS

172 Otis Ave, Woodside, CA 94062(415)851-1172

Circle 282 on Inquiry card.

DIGITAL RESEARCH COMPUTERS

(214)271-3538

32K S-100 EPROM CARDNEW!

USES 2716'sBlank PC Board - $34

ASSEMBLED & TESTEDADD $30

SPECIAL: 2716 EPROM's (450 NS) Are $9.95 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 16Kblocks.

5. Cromemco extended or Northstarbankselect.

6. On board wait state circuitry if needed.

Any or all EPROM locations can be

disabled.

Double sided PC board, solder-masked,

silk-screened.

Gold plated contact fingers.

Unselected EPROM's automatically

powered down for low power.

Fully buffered and bypassed.

12. Easy and quick to assemble.

32K SS-50 RAM

$299

00

KIT

For 2MHZAdd $10

Blank PC Board$50

For SWTPC6800 - 6809 Buss

Support IC's

and Caps

$19.95

Complete Socket Set

$21.00

Fully Assembled,

Tested, Burned In

Add $30

„:,jiiiini iikiiiii

- ' •IBMBUIBI ilRtiNRHRl

El -iiiiiii H9i8iil

At Last! An affordable 32K Static RAM with full6809 Capability.

FEATURES:

1. Uses proven low power 2114 Static RAMS.

2. Supports SS50C - EXTENDED ADDRESSING.

3. All parts and sockets Included.

4. Dip Switch 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

16K STATIC RAM SS-50 BUSS

III IIII HI II ■ III.

PRICE CUT!

iiiiiiiiiiiiiiii

lilliEIIllilllll

FULLY STATIC!

KIT FEATURES

1. Addressable as four separate 4K Blocks.

2. ON BOARD BANK SELECT circuitry (Cro-memco Standard1). 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 andsilk screened layout. Gold plated contact fingers

6 All address and data lines fully buffered. ASSEMBLED & TESTED-ADD $35

7 Kit includes ALL parts and sockets

8. PHANTOM is jumpered to PIN 67.

9. LOW POWER: under 1.5 amps TYPICAL fromthe+8 Volt Buss

10. Blank PC Board can be populated as anymultiple of 4K.

FOR 2MHZADD $10

BLANK PC BOARD W/DATA-$33

LOW PROFILE SOCKET SET-S12

SUPPORT IC'S & CAPS-$19-95

FOR SWTPC6800 BUSS!

OUR #1 SELLINGRAM BOARD!

KIT FEATURES:

1 Addressable on 16K Boundaries

2 Uses 2114 Static Ram3. Fully Bypassed

4 Double sided PC Board Solder maskand silk screened layout

5 A1! 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 ANDTESTED - $35

«<&* STEREO! *e»

S-100 SOUND COMPUTER BOARD

COMPLETE KIT!$8495

(WITH DATA MANUAL)

At last, an S-100 Board that unleashes the full power of twounbelievableGeneral lnstrumentsAY3-8910NMOS computersound IC's. Allows you under total computer control togenerate an infinite number of special sound effects forgames or any other program. Sounds can be called in BASIC.ASSEMBLY LANGUAGE, etc.KIT FEATURES:

* TWO Gl SOUND COMPUTER IC'S

* 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. QUICK, 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:

SCL" is now available! Our Sound Command Language makes writing Sound Effects programsa SNAP! SCL" also includes routines for Register-Examine-Modify. Memory-Examine-Modify,and Play-Memory. SCL™ is available on CP/M* compatible diskette or 2708 or 2716. Diskette •$24.95 2708 - $19.95 2716 - $29.95. Diskette includes the source. EPROM'S are ORG atE000H (Diskette is 8 Inch Soft Sectored)

BLANK PC

BOARD W/DATA

$31

SPECIAL PURCHASE!

UART SALE!

TR1602B - SAME AS TMS6011,AY5-1013, ETC. 40 PIN DIP

TR1602B

$2

95

EACH

4 For $10

00

CRT CONTROLLER CHIP

SMC #CRT 5037. PROGRAMMABLE FOR 80 x 24, ETC. VERY RARESURPLUS FIND. WITH PIN OUT. $12.95 EACH.

4K STATIC RAM

National Semi. MM5257. Arranged 4K x 1. +5V, 18 PIN DIP. ALower Power, Plug in Replacement for TMS 4044. 450 NS.Several Boards on the Market Will Accept These Rams. SUPERSURPLUS PURCHASE! PRIME NEW UNITS!8 for $16 32 for $59.95

NEW! G.I. COMPUTER SOUND CHIP

AY3-8910. As featured in July, 1979 BYTE! A fantastically powerful Sound & MusicGenerator. Perfect for use with any 8 Bit Microprocessor Contains: 3 Tone Channels.Noise Generator, 3 Channels of Amplitude Control. 16 bit Envelope Period Control, 2-8Bit Parallel I/O. 3 D to A Converters, plus much more! All in one 40 Pin DIP. Super easyinterface to the S-100 or other busses. $11.95 PRICE CUT!

SPECIAL OFFER: $44^35- each 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%Tax. Foreign orders (except Canada) add 20% P & H. Orders over $50, add85G for insurance.

•TRADEMARK OF DIGITAL RESEARCH.

WE ARE NOT ASSOCIATED WITH DIGITAL RESEARCH OF CALIFORNIA, THE SUPPLIERS OF CPM SOFTWARE.

NEW!

interface Converts

Your Typewriter

into Printer

• Finest print quality • Lowcost

• Easy installation • Quick delivery

• Fits IBM SELECTRIC* typewriter with no modification.

• For TRS-80S, Apple®, or any parallel or RS232 port.

• Write or phone for more information, today!

<s

,p

— U.S. and worldwide sales —

EX

INTERNATIONAL INC.16140 valerio St.

Van NUVS.CA 91406 USATEL: 213/781-0020 TLX/TWX: 910-495-1767

PRIAM

Disk Subsystems

and

Accessories,

(SMD interface available)lowest cost and greatest established relia-bility for H.P., DEC, Apple, Z-80, 8085 ... andso on.

We can show you how to overcome"foreign disk" warranty worries.

Special Opportunity:

14A. S-100 Power Supply Kit

Input: 95-220VAC, 50/60 Hz *oftOutputs: 14A@±8VDC $Zv

2A@+18VDC

Includes: UL Spec. Transformer, Rectifiers,Computer Grade Capacitors. RFI line filter,and Schematics.

ADVANCED TECHNOLOGY

735 Loma Verde, Palo Alto, CA 94303

415-493-5930Send 36 ct SASE for our 16 page flyer.

DATAPOINT

1134 Diskette Systems

16k Processor with Four Diskettes(1 Megabyte). 80 CPS MatrixPrinter. Nationwide maintenanceavailable.

$2,645

SOFTWARE AVAILABLE

DISK OPERATING SYSTEM

SORT UTILITY

ISAM UTILITY

ALSO AVAILABLE FOR S250 EACH.

A/P, A/R, GENERAL LEDGER, PAYROLL. TIME

ACCOUNTING, AND INVENTORY

AMERICAN COMPUTER EXCHANGE

100 N. MAIN ST. BOX 52

CHAGRIN FALLS, OH 44022

216-247-2100

Circle 184 on Inquiry card.

Circle 11 on Inquiry card.

Circle 19 on inquiry card.

FORTH

FOR/MAT™

SCREEN EDITOR

A MUST FOR THE SERIOUS FORTHPROGRAMMER

• All code is Forth-79 standard. Each line of code isfully explained and flow-charted (Forth style) foreasy modification.

• This editor works just like the popular wordprocessors on the market except it is written in highlevel forth and is confined to the 1024 byte boundaryof a forth screen.

• There are over 20 different commands for cursorpositioning, text modification, tabs, relocating lines,spreading lines, and moving lines to other screens.

• Insert mode is toggled on and off for midstreaminsertions and deletions. Text ahead of CP is movedright during insertion and left during deletion ifinsert mode is on.

• Column position is displayed at all times.

• Bomb proof — all unused control codes aretrapped.

• Must be used with a CRT that has cursoraddressing or with a memory mapped video.

• Send check or money order in the amount ofS50.00 and receive complete source code,flowcharts, documentation, and instructions for

brin

I up on your system.

KV33 CORPORATION

P.O. BOX 27246TUCSON, AZ 85726(602) 889-5722

W

BIBLIOTEK

The BibliographicManagement System

• Includes journals, books and symposia(patents, technical reports, governmentdocuments available soon!}

• A minimum of 500 references per bibliography

• Rapid citation entry through multi-page videoforms

• Search by authors, titles, editors, dates and/orkeywords

• User defined output formats

• Requires 48K Apple II, ROM Applesoft & twodrives

• $300.00

Scientific Software Products

3171 Donald Avenue

Indianapolis, IN 46224

(317)290-0407

IN residents adrJ 4% tax please Dealer inquiries wel

■Apple II ana Applesoft are trademarks of Apple Computer Co.,Visa and Miislercharge Accepted

FULL ELIZA FOR YOUR MICRO!

iligenc

lathe'flpist who analyzes each statement .tri her own comment or question Response:r remarks are often statllmgly appropriate

ly stripped down versions lacking the sophi

i.ELIZA is

n any CP'Ma3JK COWemgoltereil

PrOHram, written in MIcrosoM BASIC 60. Version 5 XX, lor only S20;uJililionai Orrlcryour copy of ELIZA today and -you'll never anam wonder how to respond when oneol your IrienOs says. "Okay, lets see what Ihis compulerof yours can aclually do'"

HERE IS AN ACTUAL SAMPLE OF ELIZA'S CONVERSATIONAL ABILITY:(ELIZA'S comments are printed in capital letters)

YOUR BOYFRIEND MADE YOU COME HERE ■ THAT'S INTERESTING

WHAT WOULD IT MEAN TO YOU IF YOU GOT SOME HELP-'Perhaps I could learn lo get along wilh my molherTELL ME MORE ABOUT YOUR FAMILYYou are like my lalher in some waysWHAT RESEMBLANCE DO YOU SEE?

DOES IT PLEASE YOU TO BELIEVE I.

MESTO MIND V'.

RAID OF YOU^

HINKOF YOUR FA

THE FACT THAT

ARTIFICIAL INTELLIGENCE RESEARCH GROUP

921 NORTH LA JOLLA AVENUELOS ANGELES, CALIFORNIA 90046 „_

(213)656-7368 (213)654-2214 ^5

MC, VISA, and CHECKS ACCEPTED ■■

Circle 193 on inquiry card.

Circle 327 on Inquiry card.

Circle 30 on inquiry card.

FREE!

1981

DISCOUNT

ELECTRONICS

CATALOG

JOIN THE PAK!

Penny Sales, Fn

Electronic Products such as Computer Periph-erals, Integrated Circuits, S|Equipment, Rechargeable B-"-ucts. Semiconductors, and ...».-..,Take advantage ol our 25 years as America's

r of discount electronics

POLY PAKS, INC.

CP/M® CompatibleSGOLD DISK$Z-80 Software

Z-80 Disassembler Jft | /S

ppdcreates assembly language source files

E-Z Text

$75.

ppdunique text file word processor

Bower-StewartSi Associates

POST OFFICE BOX 1389HAWTHORNE, CALIFORNIA 90250^^h 213/676-5055

VSv-i Trademark

■■■■J Digital Research

database manager

fbrTRS 80 Model I

• CREATE random access disk files15 fields or 255 bytes/recordFiles can span 4 disk drivesPassword protected file access

• Database DIRECTORY displays alluser files and their attributes

• Powerful TRANSACTlONS-add,edit, read, delete S list recordsEfficient binary tree sorts

• Sophisticated QUERY with multi-key relational & logical operations

• REPORT formatter requires onlyfor user to select desired fieldsAutomatic sub & grand totalsMay be used with lower case

• Entirely MENU DRIVEN operation■ Extensive error trapping routines

• User oriented instruction manual

• Requires 32k — 2 disk drives

Introductory price $59.95

Visa and MasterCard accepted

mentor software

816 McLane Ave-Margantovun, UVU 2G5051 Tandy Corp. Trademark

Circle 300 on Inquiry card.

Circle 47 on Inquiry card.

Circle 217 on Inquiry card.

THE STAR MODEM

From Livermore Data Systems

RS232 MODEMIEEE 488 MODEM

RS232 CCITTIEEE 488 CCITT

SALE $128SALE $199

$170$280

STAR Modem is the price performance leader with a full2 YEAR FACTORY WARRANTY.

We carry Apple 11+ fromBell & Howell

PROGRAM YOUR OWN EPROMS

Branding Iran lor PET/CBM $79

EPROM Programmtr with uftwin lor ill ROM versions.

lncludai ill necessary hinlwirg and software to program or

copy 2716 and 2532 EPROMS.

EARL lor PET/CBM $ 65

Editor, Assembler, Relocator, Linkeditor

FORTH lor PET 50

Conforms to FIG Standards

Suparfiraphlcs 30

Machine Language Graphics routines for PET/CBM

KMMM PASCAL lor PET/CBM 85

Includes translator for ROMable machine code

REVERSAL (Spracklen) 32K Apple 28.00

Super FORTH 48K Apple 40.00

Energy Miser for PET, Apple, or Zenith 24.50

Data Manager (Lutus) 24K Apple 40.00

Histo-Graph (Boyd) 48K Apple 24.50

Data-Graph (Boyd) 48K Apple 40.00

Apple II User's Guide (Osborne) 12.00

Introduction to Pascal (Sybex) 10.30

Pascal Handbook (Sybex) 12.00

Graphics Cookbook for Apple 9.90

Musical Applications of Micros (Chamberlin) 20.00

Basic FORTRAN (Coan) 7.25

RAM/ROMfor PET/CBM

4K or 8K bytes of softROM with optional Battery Backup

Programmable like RAM, protectable like ROM.Plugs into ROM socket in any large keyboard PET/ROM to use.Plugs into ROM socket in any large keyboard PET/CBM.Save your ROM images on disk, load in RAM/ROM to use.

RAM/ROM with 4KRAM/ROM with 8KBattery Backup Option

$ B5

120

30

MIPLOT Intelligent Plotterby Watanabe Instruments (Digiplot)

SPECIAL

$1195

SPECIALS

EPSON MX-80 PrinterEPSON MX-80 F/T PrinterEPSON MX-70 PrinterEPSON MX-100 Printer

Centronics 739 Printer with Dot GraphicsSTARWRITER Daisy Wheel PrinterZENITH DATA SYSTEMS

Z19 Video TerminalZ89 with 48KExtra 16KRAMZ-47 Dual 8" Drive

6751445

7292150

1152775

Zenith ZVM-121 Green Phosphor Monitor 120

Zenith Color Monitor 360

Amdek Color Monitor 360

Synertek Systems

SYM-1 Microcomputer SALE 209

SYM BAS-1 BASIC or RAE 1/2 Assembler 85

KTM-2/80 Synertek Video and Keyboard 349

KTM-3/80 Synertek Tubeless Terminal 400

Complete CBM BUSINESS SOFTWARE PACKAGE

Can be tailored to meet most business requirements

65026502A6520 PIA6522 VIA6532

7.45 10/6.95 50/6.55

8.40 10/7.95 50/7.35

5.15 10/4.90 50/4.45

6.45 10/6.10 50/5.75

7.90 10/7.40 50/7.00

2114-L200 ns RAM 3.75 25/3.50

2114-L300 ns RAM 3.15 25/2.90

2716 EPROM 7.00 5/6.45

2532 EPROM

6116 Hitachi 2K x 8 CMOS STATIC RAM

4116 200ns

Zero Insertion Force 24 pin Socket

100/6.15

100/6.90

100/4.15

100/5.45

100/6.60

100/3.25

100/2.65

10/5.90

14.50

14.50

8 for $20

■ $2.00

^»k.

commodore

<0>

DISKSPECIALS

CASSETTES - AGFA PE-611 PREMIUM

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.

•

CBM-PET SPECIALS

Up to $380 tree morchondlse

with purchase of one

of following CBM-PET Items:

8032 32K, 80 x 25 CRT, business keyboardMicro Mainframe - available soon8050 Dual Disk Drive-1 megabyte capacity 1795 3808250 Dual Disk Drive - 2 megabyte available soon2031 Single Disk Drive 695 135

4016 full size graphics keyboard 995 200

4032 full size graphics keyboard 1295 275

4040 Dual Disk Drive 1295 275

4022 Tractor Feed Printer 795 160

C2N External Cassette Deck 75 13

VIC 20 Personal Computer 300 25

Used CBM/PET Computers CALL

8024-9 High Speed Printer available

WRITE FOR SYSTEM PRICES

*** EDUCATIONAL DISCOUNTS ***

Buy 2 PET/CBM Computers, receive I FREE

SCOTCH (3M) 5'/4" 10/2.85 50/2.75 100/2.65SCOTCH (3M) 8" 10/2.90 50/2.80 100/2.70

Verbatim 5'A" 10/2.45 50/2.40 100/2.35

(add 1.00 for 5%" Verbatim plastic storage box)Verbatim8" Dbl. Dens. 10/3.45 50/3.35 100/3.25BASF 5'A" 10/2.40 20/2.35 100/2.30

WRITE for prices on WABASH DisksWE STOCK MAXELL DISKS

Diskette Storage PagesDisk Library Cases

10 for 3.952.85 5"-2.15

A

ATARI 800 $745

All Atari Modules 20% OFF

4 PART HARMONY MUSIC SYSTEM tor PET

The Visible Music Monitor, by Frank Levinson, allows youto easily enter, display, edit and play 4 part harmonymusic. Includes whole notes thru 64ths (with dotted andtriplets), tempo change, key signature, transpose, etc. TheKL-4M unit includes D to A converter and amplifier (addyour own speaker).KL-4M Music Board with VMM Program $59.90

WordPro 3+ - 32K CBM, disk, printer

250

WordPro 4+ - 8032, disk, printer

335

OZZ Data Base System for CBM 8032

335

VISICALC for PET or ATARI

170

SM-KIT - Super PET ROM Utilitites

40

Programmers Toolkit - PET ROM Utilities

34.90

PET Spacemaker II ROM Switch

36.00

2 Meter PET to IEEE or IEEE to IEEE Cable

40.00

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

Library of PET Subroutines

17.00

252 Bethlehem PikeColmar, PA 18915

215-822-7727

A B Computers

ATARI EDUCATIONAL PLAN Write lor details.

A P Products 15% OFFA P Hobby-Blox 15% OFF

ALL BOOK and SOFTWARE PRICES DISCOUNTED

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 Applications Book (Zaks) 10.45

6502 Software Cookbook (Scelbi) 9.45

CP/M Handbook (w/ MP/M) Zaks 11.85

Practical BASIC Programs (Osborne) 13.60

Some Common BASIC Programs (Osborne) 12.75

WRITE FOR CATALOG.

Add $ 1.25 per order for shipping. We pay balance of UPS surface chargeslon all prepaid orders Prices listed are on cash discount basis.Regularprices slightly higher

Circle 3 on inquiry card.

BYTE October 1981 495

IC-IRS will Find It

IC-IRS S37.50 19S0CMDB $29.95

IC-IRS by Island Cybernetics is THE Information RetrievalSyitem for Indexing and retrieving entries with largeamounts of FREE FORM TEXT, such as ABSTRACTS;CORRESPONDENCE FILES (with complete letters); At-torney's CASE NOTES, CONTRACTS, WILLS; MD'S andScientist's JOURNAL ARTICLES; or any other similartype of information. EASY TO USE.

COMPUTERIZE your CARD FILES or MAIL LISTS.

IC-IRS runs as a ".com" file on CP/M* compatiblesystems with 2 disk drives and 32K memory. IC-IRS iswritten In CONVERS for fast execution. It searches the904 entry 1980 COMPUTER MAGAZINE ARTICLE DATABASE in 25 seconds using combinations of KEY WORDSwith up to 65 "and"s and 32 "or"s.

Get IC-IRS and the 1980 COMPUTER MAGAZINE ARTI-CLE DATA BASE (1980 CMDB) on standard 8"SD disks or5 1/4" disks In several popular formats.

IC-IRS 2.07 with manual = $37.50 + $2.50 postage.1980 CMDB = 529.95 (no postage with IC-IRS)

Call (512) 2584310 and use your MASTERCARD or VISA,

use the bingo card or write to:

FYI, INC.

P. O. Box 10998 #615Austin, Texas 78766

CP/M Is a registered trademark df Digital Research

Circle 156 on inquiry card.

LABELS

15/16"x3%" white pressure

1 up - pin feed sensitive

PRICE INCLUDES SHIPPING

Packed 5M per box - Min. order 1 box -$14.75Check with order - Mass Residents add 5% Sales Tax

CHECK-MATE

P.O. Box 103, Randolph, MA 02368Telephone: 617-963-7694

LOWEST POSSIBLE PRICESBEST POSSIBLE WARRANTY

model III 16K

$839

colorcomputer 4K

$310

call TOLL FREE 1-800-343-8124

nvnnulpr245A Great R°ad

^A-n ■ iMVI« Littleton, MA01460

Write tor yourfree catalog.

TRS-80 15 a 'egrsiered trademark ol Tandy Cor

plus

617 • 486 • 3193

Circle 86 on inquiry card.

MEMOREX

FLEXIBLE DISCS

WE WIUL NOT BE UNDER-SOLD!! Call Free (800)235-4137

for prices and information. Dealerinquiries invited and C.O.D.'saccepted

VISA

PACIFICEXCHANGES

100 Foothill Blvd.San Luis Obispo,CA 93401 In Cal.call (800) 592-5935or (805) 543-1037

FULL PERFORMANCE CP/M* computer$1995 list

dealer-distributor discounts

£j± Alspa Computer, Inc.

5215 Scotts Valley DriveScotts Valley, CA 95066(408) 438-3326

"trademarks of Digital Research, Inc.

Circle 15 on inquiry card.

COMPUTER SHOWS

SECOND ANNUAL

NJ MICROCOMPUTER

SHOW AND FLEAMARKET - 1981

NEWARK, NEW JERSEY

Sat. Oct. 24 o Sun. Oct. 25

10-5:30 PM « 10-3:00 PM

HOLIDAY INN (NORTH)

NJ Turnpike • Exit 14

(Take Route 1-9 Service Road - Follow Signs)

REGISTRATION $5.00 -

FLEAMARKET ONLY $3.00

Fleamarket Permits $5/Spot

(Includes Admission)

Commercial Exhibits* User Groups* Fleamarket

SECOND ANNUAL

NATIONAL"80" MICROCOMPUTER

SHOW (FOR TRS-80* USERS)

April 29,30, May 1, 1982

NEW YORK STATLER HOTELNEW YORK CITY

100 Exhibit Booths • Speakers* User Groups*TRS-80 is a Trademark of Tandy Corporation

For Registration, Exhibitor or Fleamarket

Information Contact:

KENGORE CORPORATION

3001 Route 27 . Franklin Park, NJ 08823

(201) 297-2526

Circle 64 on Inquiry card.

Circle 289 on inquiry card.

Z-80 and 8086 FORTH

Z-80r FORTH—a complete program development system. Usesstandard CP/M* compatible random access disk files for screenstorage. Package includes: interpreter/compiler with virtual mem-ory management, line editor, screen editor, Z-80 Assembler, de-compiler, utilities, demonstration programs, and 80 page usermanual. System requirements: Z-80 microcomputer, 48 kbytesRAM. CP/M 2.2 or MP/M1 1.1. $50.00

Z-80 FORTH WITH NAUTILUS SYSTEMS CROSS-COMPILER.

Extend/modify the FORTH runtime system, recompile on a hostcomputer for a different target computer, generate headerlesscode, generate ROMable code with initialized variables. Supportslorward referencing to any word or label. Produces load map andlist of unresolved symbols. 107 page manual. System require-ments as for Z-80 FORTH above, $200.00

8088 FORTH with line editor, screen editor, assembler, andutilities. Uses standard CP/M compatible random access files forscreen storage. Requires 8086 or 8088 microcomputer, 64 kbytesRAM, and CP/M-86 operating system. $100.00

MACHINE TEST PROGRAM PACKAGE for Z-80 systems. Includesmemory, floppy disk, printer, and terminal tests with all sourcecode. Requires CP/M 2.2. $50.00

All software distributed on eight-Inch solt sectored single densitydiskettes. Prices include shipping by first class or UPS within USAor Canada. COD charges extra. Purchase orders accepted at ourdiscretion, (CP/M and MP/M are registered trademarks ol DigitalResearch, Inc. Z-80 Is a registered trademark of Zllog, Inc.)

Laboratory Microsystems

4147 Beethoven Street

Los Angeles, CA 90066

(213)390-9292

RS-232 PROBLEMS?

ki*&44i&

LET THE RS-232 TESTER HELP YOUSOLVE YOUR COMPUTER INTERFACEPROBLEMS. DESIGNED TO CONNECTIN SERIES WITH ANY RS-232 INTER-FACE, IT DISPLAYS THE STATUS OFSEVEN OF THE MOST IMPORTANTLINES: TRANSMIT DATA, RECEIVEDATA, REQUEST TO SEND, CLEAR TOSEND, DATA SET READY, CARRIERDETECT, AND DATA TERMINALREADY. THE RS-232 TESTER RE-QUIRES NO POWER AND MAY BELEFT IN THE LINE PERMANENTLY.

$39.95 POST PAIDB & B ELECTRONICS

BOX 475/MENDOTA, IL 61342

1802fig-FORTH

high-level compiler language

10- 20X faster than BASIC

ELF II1 Super ELF /Other

w/assembler-editor $60

w/mntro ossemb.screen-editor $80extras

on cassette/requires 12k+RAM

P.O. Box 3AK

ftus-ttn. T«MW

78712

19B3 Rio Grand*

Rus-tin. r#x*»

78785

Circle 195 on Inquiry card.

Circle 40 on inquiry card.

Circle 155 on inquiry card.

Belmont, California 94002

of over 500 items availablefrom 600 authorized Jim-pak Distributors:

7400 .. .

7402 . . .

7404 .. .

7406 2/1.19

7407 2/1.19

7408 .. .

7410 . . .

7414 . ■. 99

7417 2/1.10

7420 2/.85

7447 1.19

7474 69

7475 79

7476 69

7485 1.19

7486 2/1.19 74367

7489 2.99 74393

TTL ffllp

2/.85 7490 85

2/.85 7493 85

2/.85 74100 2.25

74109 2/1.19

74121 69

2/.89 74123 99

2A85 74150 1.95

74154 1.95

74157 99

74161 1.19

74164 1.59

74174 1.59

74175 1.49

74192 1.19

74193 1.19

... .99. . . .1.95

POTENTIOMETERS

l j

3/4 Watt @ 70°C15 Turn Pot.Linear Taper

100ft 500fi 1K5K 10K 50K100K 500K 1Meg

830P. .$1.79

2 Watt @ 70°C

7/8" Slotted Shaft

Linear Taper

IK 5K 10K25K 50K 100K1 Meg

CMU . . $2.95

WW CMOS ^^

4000

4001 .

4002

4006

4009

4010

4011

4013

4016

4017

4018

4020

4023

4024

4027

.69

4030

.69

4040

.69

4044

1.95

4046

.89

4047

.85

4049

.69

4050

.85

4051

.85

4066

1.49

4069

1.49

4070

2.19

4071

.49

4081

1.M

4093

.89

4511

.791.951.392.492.75.89.891.951.19.79.79.79.691.191.95

CONNECTORS

u,ji.j[.j;.ji.jlj;.jujl

DB25P D-Submlnlature Plug 3.95

DB25S D-Submlnlature Socket 4.95

DB51226 Cover for DB25P/S 2.25

22/44SE P.C. Edge 2.95

UG88/U BNC Plug 2.19

UG89/U BNC Jack 3.95

UG175/U UHF Adapter .59

S0239 UHF Panel Recp. 1.49

PL258 UHF Adapter 1.95

PL259 UHF Plug 1.95

UG260/U BNC Plug 2.39

UG1094/U BNC Bulkhead Recp. 1.49

WW LINEAR WW

LM301N. .LM305H. .LM307N. .LM308N. .LM309K. .LM310N. .LM311N. .LM317T. .LM318N. .LM319N. .LM320K-5.LM7905J1

LM7912T .

LM7915T .

LM323K. .

LM324N. .

LM337T. .

LM339N. .

.591.39

.751.192.252.691.492.292.952.952.251.751.751.755.951.292.291.29

LM7805TLM7812TLM7815TLM380N.LM384N.LM555N.LM556N.LM565N.LM566N.LM567N.LM723N.LM741N.LM1310NLM1458NLM1488NLM1489NLM1800N76477N. .

1.751.751.751.492.49

.691.491.951.951.79

.79

.652.95

.991.59LB4.493.95

■R.

GRABBAGS

GB100GB101GB102GB103GB108GB110GB113GBU6GB117G8120

(jer. Caps. (100) 2.95Mylar Caps. (60) 4.95Electrolytlcs (60) 4.95Tantalums (40) 4.95TTL IC's (50)Asst. LEDs (100)Trimmers (30)V«w Resist. (200)ViW Resist. (200)Slide Switch (25)

4.955.954.952.952.953.95

GB123GB127GB137GB139GB140GB141GB145GB154GB162GB173

Heat Sinks (30) 3.95Transistors (100) 3.95Chokes (50) 3.95

Term. Strips (40) 3.95Spcr/Stndff(150) 2.95Washers (200) 2.95

Lugs (100) 2.95

l&2w Resist. (100) 2.957-Seg.Dsplys. (50)5.953/8" Pots. (100) 5.95

JE215 AdjustableDual Power Supply

General Description: The JE215 is a Dual PowerSupply with independent adjustable positive and nega-tive output voltages. A separate adjustment for eachot the supplies providesthe user unlimited applicationsfor IC current voltage requirements. The supply canalso be used as a general all-purpose variable powersupply.

FEATURES:

• Adjustable regulated power supplies,pos. and neg. 1.2VDC to 15VDC.

■^ -. • Power Output (each supply):

5VDC @ 500mA, 10VDC(s> 750mA,12VDC<a 500mA, and15VDC@> 175mA,

• Two, 3-terminal adj. IC regulatorswith thermal overload protection.

• Heat sink regulator cooling

• LED "on" indicator

• Printed Board Construction

• 120VAC input

• Size: 3-1/2"w x 5-1/16"L x 2"H

JE215Adj. Dual PowerSupply Kit (asshown). . $24.95

(Picture not shown but similar in construction to above)JE200Reg. PowerSupply Kit (5VDC. lamp) . . $14.95JE205 Adapter Brd. (to JE200) ±5,±9 & ± 12V. . $12.95JE210Var. Pwr. Sply. Kit, 5-15VDC,to 1.5amp. . $19.95

DESK TOP ENCLOSURES

DTE-8 (Pictured) $31.95

DTE-11 (Pictured) 34.95

DTE-14 (Pictured) 36.95

DTE-HK (Case for JE600) 47.95

DTE-AK (Case for JE610) 52.95

JOYSTICKS

JS-100K 100K Linear Taper Pots $5.49

JVC-40 40 K (2) Video Controller 5.95

WALL TRANSFORMERS

AC250DV9200

250mA 12VAC (117V/60Hz).200mA 9VAC (117V/60Hz).

$3.953.95

WW LS Schottky WW

74LS00 55 74LS109 .

74LS02 55 74LS123 .

74LS04 69 74LS138 .

74LS08 55 74LS139 .

74LS10 55 74LS154 .

74LS14 1.09 74LS157 .

74LS30 55 74LS161 .

74LS32 69 74LS174 .

74LS38 69 74LS175 .

74LS42 1.49 74LS192 .

74LS47 1.49 74LS193 .

74LS48 1.79 74LS221 .

74LS73 79 74LS244 .

74LS74 79 74LS245 .

74LS75 99 74LS367 .

74LS85 1.95 74LS374 .

74LS90 1.09 81LS97. .

. .791.951.491.492.491.491.791.791.791.891.891.952.493.491.292.492.49

SOCKETS

Low Profile

8 pin LP .14 pin LP .16 pin LP .18 pin LP .20 pin LP .22 pin LP.24 pin LP .28 pin LP .36 pin LP.40 pin LP .

Wire Wrap

2/.59 14 pin WW tin .75

2/.69 14 pin WW gold 1.09

2/.79 16 pin WW tin .79

2/.89 16 pin WW gold 1.19

2/.99 24 pin WW gold 1.69

2/1.09 40 pin WW gold 2.75

.79 14 p. plug/cover 1.29

.82 16 p. plug/cover 1.39

.99 24 p. plug/cover 1.95

1-19 Also,The Molex Line

DIODES & TRANSISTORS

IN751 . . . .

IN757 . . . .

IN1188. . . .

IN3600. . . .

IN4001. . . .

IN4004. . . .

IN4007. . . .

IN4148. . . .

IN4733. . . .

IN4734. . . .

IN4735. . . .

IN4742. . . .

IN4744. . . .

. 2/.59

. 2/.59

. 2.69

. 5/.99

. 4/.59

. 4/.69

. 4/. 79. 10/.99

. 2/.69

. 2/.69

. 2/.69

. 2/.69

. 2/.69

2N2219A. . . .2/1.192N2222A. . . . 2/.892N2907A. . . . 2/.89

2N3055 99

2N3772 2.25

2N3904 2/.69

2N3906 2/.69

2N4401 2/. 79

2N4403 2/. 79

2N5129 2/.69

2N5139 2/.69

2N5210 2/. 79

2N5951 2/1.29

CAPACITORS

Dipped Tantalum

.lmfd@35V 2/.89

.47mfd@35V

lmfd@35V

2.2mfd@25V

3.3mfd@25V

4.7mfd@25V

10mfd@25V

33mfd@25V

100V MYLAR.001-.01mfd 4/.79

.022mfd.047m fd.lmfd.22mfd

2/.892/.892/1.092/1.192/1.391.193.95

4/.894/.994/1.194/1.29

ELECTROLYTIC

lmfd@50V 3/.69

4.7mfd@50V

10mfd@50V

22mfd@50V

47mfd@50V

100mfd@50V

220mfd@50V

1000mfd@25V

2200mfd@16V

50V CERAMIC10pf-.022mfd 4/.69.047mfd 4/.69

.lmfd 4/.79

2/.59

2/.69

2/.79

2/.89

.59

.69

1.19

1.39

MICROPROCESSORS

Z80A CPU (4MHz) 14.95

MC6800 8 Bit MPU 14.95

8080A CPU 6.95

8212 8 Bit I/O Port 3.95

8216 Bl-Dlrectlonal Bus Driver 4.49

2513/2140 Character Generator 12.95

8T97 Trl-State Hex Buffer 2.25

AY-5-1013 30K Baud UART 6.95

AY-5-2376 88-Key Keyboard Encoder 13.95

2114-3 4K Static RAM C3fluns) 6.95

MK4116 16K Dynamic RAM (250ns) 4.95

2708 8K EPROM 6.95

2716 16K EPROM (+5VJ 10.95

Function Generator Kit

Provides 3 basicwaveforms: sine,triangle and squarewave. Freq. rangefrom 1 Hz to 100KHz. Output ampli-tude from 0 voltsto over 6 volts(peak to peak).Uses a 12V supplyor a ±6V split sup-ply. Includes chip,P.C. Board, com-ponents & instruc-tions.

JE2206B. $19.95

Circle 191 on inquiry card.

BYTE October 1981

497

TERMINAL

DATA

CORPORATION

MODEL 1200 RS-232 BI-DIRECTIONALDATA SPLITTER

available in kit form

Model 1200K gives the terminal or micro-processor user a second interface for a printer,plotter, cassette or tape drive. It operates at anyspeed & isolates the two output devices fromeach other, while providing 2 RS-232 interfacesfrom the terminal or microprocessor.

The kit consists of 3 RS-232 connectors,printed circuit board, all necessary components,enclosure, mounting hardware & assembly in-structions $75.00

write or call

TERMINAL DATA CORP.

1187B Coakley Cir.

RockvillB, MD 20852

(301)881-7655

ZEN is HERE

FAST SCREEN EDITINGforCP/M & NORTH STAR

OPEN PROGRAMS WITH SOURCE FILES

e In contol antl ZEN may be reassembh5tom features. Call system and n

•spo-ndence and sourct

.TXT, etc. types.

.sary but addressabh

easier to usI Ing I ists, r>( .ASM, ,BAS,system with con

ILai

CPM version (or 1.4 thru MPM releases, use theirassembler and line command conventions which caninclude multiple command lines.

North Star DOS versions have a disc assembler, anextensive monitor and some Basic utilities. They usethe N.S. line editing conventions.

Specify version # ZEN1.1 5" SD NS 2000

ZEN2.1 8" SDSS CPM ZEN1.2 5" DD NS 2000

ZEN2.2 5" DD NS CPM ZEN1 .3 5" DD NS 0100

Disc and Manual S75 Manual alone $1 5

CA residents add 6% Send check to:

i CONTROLS COMPANY

'965-49961S7SA.P.S. SANTA BARBARA CA 93103

NEW 16K-RAMPERSONAL COMPUTER

$00000 FACTORY SALEa£a£*7 PRICE

For $229°° you get the new InteractModel "R" Computer, 16K-RAM,2K-R0M, 8080A Microprocessor,color, sound, full 53 keyboard, highspeed cassette, AC adapter, R.F.Modulator, Black Console Case, 90days parts and labor warranty,owners' guide, FCC approved.15 DAY FREE TRIAL Return within15 days complete and undamagedfor refund of purchase price.

PROTECTO ENTERPRIZES

BOX 550, BARRINGTON, IL 60010TO ORDER PHONE 312/382-5244

Circle 364 on inquiry card.

Circle 397 on inquiry card.

Circle 308 on inquiry card.

NEW IFR FLIGHT SIMULATOR

RUNS ONApple II 48K Applesoft DOS 3.3

Puts you behind a set of instruments so realyou could actually fly an airplane with them.

No toy this. It Includes all primary in-struments, ADF, ILS, and VOR approaches,and, even an XY plot after each flight.

$25.00 at your Computer Store.

Or direct from

PROGRAMMERS SOFTWARE

Box 199

Cabot ARK 72023

(501) 843-2988

WANTED:

APPLE, PET, TRS-80, CP/M

SOFTWARE

Westico is a publisher and distributor ofprofessional software for microcomputers.If you have a new program ready fordistribution or want yourexisting programsto reach a larger market, contact:

Phillip Woellhof, V.P. Mktg.

Westico, Inc.

25 Van Zant Street

Norwalk, CT 06855

(203) 853-6880To increase your profits, take advantageof Westico's worldwide promotion anddistribution.

WESTICO

The Software Express Service

"Hen*Users

Double Yourdisk storagecapacity without adding a drive.

Get twice as much from your H88 orH89 microcomputer. Our FDC-880Hfloppy disk controller, in conjunctionwith your 51//' drives, for example,expands memory capacity from 256bytes to 512 bytes per sector.

And it handles single and double-sided, single and double-density, 8" and51//' drives — simultaneously.

Call 714/275-1272 todayor write for details.

Ol

C.D.R. Systems Inc.

Controlled Data Recording Systems. Inc.7667 Vickers St.. San Diego. CA 92111

Circle 307 on Inquiry card.

Circle 62 on inquiry card.

•-. • 1 I •■

DISKETTES

SAVE 40% SSS&Z51/4"Sgl. Dens. 26.70/10

Specify soft, 10 or 16 hard sectors

8"Sgl. Dens. 27.30/108"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 ^feAfl

Information Processing Products «HVI

■ Dysan

^CORPORATION

Solve your disc problems, buy 100% surfacetested Dysan diskettes. All orders shippedfrom stock, within 24 hours. Call toll FREE(800) 235-4137 for prices and Information.Visa and Master Card accepted. All orderssent postage paid.

PACIFICEXCHANGES

100 Foothill Blvd.San Luis Obispo. CA93401. (InCal. call(805)543-1037.)

TRS-80™* Models 1&3

SYSTEM DIAGNOSTIC .... $99.95

Tests every component of your TRS-80 forproper operation: ROM, RAM, Video Dis-play, Key board, Line Printer, Cassette Re-corder, Disk Drives, RS-232 Interface.Continuous or monitored operation.

PENCIL PATCH .... $19.95

Fixes the Electric Pencil™ Model 1 versionso that it runs on the Model 3. (You mustalready own the Model 1 version.)

SMART TERMINAL $69.95

The intelligent telecommunication pro-gram that enables your TRS-80 to be usedas a timesharing terminal. Automatic trans-mission to and from another computer.Control keys, break key, lower case, cas-sette and disk files compatible with bothElectric Pencil™ and Scripsit programs.Send S.A.S.E. for Free Catalog.

HOWE SOFTWARE

14 Lexington Road, New City, NY 10956•TRS-80 is reg. TM of Radio Shack div. of Tandy Corp.

Circle 205 on Inquiry card.

Circle 290 on inquiry card.

Circle 171 on inquiry card.

CALL US TODAY FORSPECIAL SYSTEMPACKAGE PRICES...

Now is the time to buy a completesystem of your choice...

• CROMEMCO SYSTEM 2

• DYNABYTE

• NORTHSTAR

• SUPERBRAIN

Complete with printer and software.READY TO USE!!!

Participate in our expansion sale.

MiniMicroMart is moving to larger quarters to sen/eyou with a larger staff and with the largestinventory of systems and peripherals.

MiniMicroMart, Inc.

943 W. Genesee St.

Syracuse, New York 13204

(315)422-4467

Circle 247 on inquiry card. BYTE October 1981 499

THE COMPUTERCOPY STAND.

□ For all detachable keyboards and

Apple II □ Easy on the eye (and back).

□ Keeps paper work in front of operator

and in line with screen. □ Perfect for

word processing, data entry, and

programming. D Non-magnetic

Lineguide,™ tilt adjustable.

Pkay Corporation

RO. Box 11463 • Costa Mesa, CA 92627714/548-2081

DON'T GETSTUCK.

Sloppy software contracts

cost money and cause

misunderstandings. Consult

us before you sign a contract

We offer contract services to

both customers and suppliers

Call or write

Robert E. Brown, Esq.

(716) 232-5300.

■ Basic ■ Forth ■ Cobol■ Fortran ■ Others

Middleton,Wilson, Boylan & Gianniny,

Attorneys at Law

900 Midtown Tower. Rochester. NY 14604

3

ELECTRONICS

BLL FDR QURLITy CDrhPDHErVTS

UDER^simiM- ^Ssa

ALL ASSEMBLEDCPU Z 6MHz CSC $308 CPU Z 4MHz 179CPU 80S5/88 CSC 399 CPU 8085/8 319DISK 1 371 CPM*80 135CPM*86 w/d1 235 OASIS CALLDISK SYSTEM CALL INTERFACER 1871NTERFACER 3(5) 467 INT-FACC8) 517BIG 8 PKG 1795 RAM 20 32K 425RAM 17 61K 821 SPECTRUM 297ENCLOSURE 2 DK 619 ENCLOS RACK 6716MHz CPU Z SYSTEM 61K DUAL 8" 37956MHz CPU 8085/8088 SYSTEM 64K 3895EPSON MX80 160 MX100FT 765TELEVIDEO 910,920, & 950 CALLAMPEX DIALOGUE 975 ADDS V.P, 519

ALL PRICES SUBJECT TO CHANGECPM IS TRADEMARK OF DIGITAL RESEARCH

-PO & Dx. qsi

-LfESTrhinSTEP Cft q9b<5=^^

"JIN Sb^S HHb

Circle 299 on Inquiry card.

Circle 242 on inquiry card.

Circle 337 on inquiry card.

SPECIALS of the MONTH

ATARI 800 Computers i 750.00

ATARI 810 Disc Drives i 450.00

ATARI Softwore 25 % off

APPLE II & 46 K Computers i 1,150.00

L0B0 Disc Drive for APPLE II S 095.00

8" Dual Drive Subsystems 2.4Mb

DS-DD complete $1,795.00

CDC LARK Subsystems 16Mb with 1

cartridge-power supply-cobles. $5,200.00Complete Word Processing System

with DIABLO Primer $4,200.00

CALIFORNIA Computer Systems 300 Dual8" Drive Computer. 64K RAM, OASIS-2.4Mb Disc memory, 25 serial ports, 1Centronics compatible parallel port, otelevideo 910 CRT-COMPLETE!. $5,800.00

EP50N MX-70 Printers $ 385.00

EPSON MX-80-F/T Printers $ 685.00

IDS 460G Printers $ 800.00

IDS 560G Printers $ 1,150.00

CITOH STARWRITER 25 Printers. . . . $1,380.00

DIABLO 630 RD Printers $2,240.00

NEC SPINWRITERS Call for price

APPLE Peripherals Call for price

MOUNTAIN HARDWARE CPS

Multifunction Cords $ 180.00

AUTO-DIAL/AUTO-ANSWER

MODEM

FOR$224.95!*

The MICROCONNECTIONP can dialand answer the telephone, runprinters, decode busses, transcribetransmissions, answer/originate anddirect-connect to the telephonesystem. Lots of terminal and hostsoftware too. For more informationwrite or phone:

the microperipheral corporation

2643a- 151st PI. N.E.

Redmond, WA 93052(206) 881-7544■RS233 MICROCONNECTIONiM

BASYS/1

CMOSSingle-BoardComputers for

ROBOTICS

3ASYS/1 is a CMOS microcomputer for real-world appli-cations It contains the on-board I/O to handle motors,switches, lights, and solenoids directly, without externalparts To demonstrate, we built ITSABOX. the IntelligentTurtle Robot. He's programmed to speak 8TH, our versionof FORTH, and cost under S300. Parts: BASYS/1. 2stepping motors. 2 sensing switches, an RS-232C connec-tor, batteries and a box. Drop us an SASE and we'll tell youall about him.

1 MSI does not sell ITSABOXes. but we do design and buildCMOS microsystems for control applications. If your appli-cation could use the advantages of CMOS logic and micro-computer technology, give us a call!

BASYS/1 with 1K RAM, .5K ROM. Kit $185,

assembled S220

TECHNICAL MICRO SYSTEMS, INC.366 CloverdaleAnn Arbor, Ml 48105(313) 994-0784

Circle 215 on Inquiry card.

Circle 359 on inquiry card.

Fast Action

Games

For Your Apple!

Sirius Software, Inc.

Dealer inquiries invited.

For more information contact your

local computer dealer. (916) 920-1939

2011 Aiden Way #2 Sacramento, CA 95825

Circle 336 on inquiry card.

The V.I.P.* IS HEREI

'Versatile Instrumentation Peripheral

Perfect for Use in Process Control and Data Acquisi-tion Systems or in Standalone Instrumentation

High Performance and Resolution

Extremely Cost Effective

* Single Card SI00 A/D, D/A, Digital I/O

* Instrumentation Amplifier Input Channel

* D/A Voltage and Current Source Output

* Full 12 Bit Resolution

* Software Configurable Analog Circuitry

* 25 /is A/D Conversion Time

* 48 High Voltage, High Current Digital Drivers,100 mA per Output

' Drives LED Display and Decimal Points with Soft-ware Selectable ROM Decoding

* Two Double Pole Utility Relays

* 8 Bit TTL-Compatible Input

* Self-Test Capability

$595

Fully assembled and tested. Documentation and ap-plications software provided. Check, MO, MC, Visaaccepted. MA residents add 5% sales tax. $4 shippingand handling charge.

AUTOMATED CONTROL SYSTEMS

1105 BroadwaySomc-rville, MA 02144(617)628-5373

CHIPS*

&DALE £3

THE INFLATION FIGHTERS!_ RAM —

4116200ns8/$15.75

2il4L300ns8/$18.454164 200nS $27.00

— EPROM —

2716(5V)450nS8/$5.35ea. $5.75 ea.

2732 (5v)450ns8/$13.00ea. $14.00 ea.

We buy from Manufacturer's AuthorizedDistributors. All Chips are fullyGuaranteed. Call for quantity pricing.

Please allow up to 3 wks. for personal checks to

clear.

Add S2.50 Shipping & Handling

C.O.D. 53.00. Wash, residents add 5.4". Sales Tax

CHIPS & DALE

P.O. Box 31607

Seattle.Wash.ziP98i03 Master Charge1-206-524-9126 VISA accepted.

Circle 37 on inquiry card.

Circle 66 on Inquiry card.

yc/t.

ELECTRONICS

INTEGRATED CIRCUITS

P.O. Box 4430XSanta Clara, CA 95054

Will calls: 2322 Walsh Ave.(408) 988-1640 TWX 910-338-2139

Same day shipment. Firs! line parts only Factory tested.Guaranteed money back. Quality IC's and other compo-nents at factory prices.

warn

74O0NMOJN7iQiU7409NM10N7414N

?»m

7432N74MN?442N7445B7447N74481174MN7474N7475N7485N7489N7490N7492N7493N7495N

74107NM1JVN

741J3N74i?SN74145N741 SON7JI51N74154NUlSffl,'4161N74162N

74I75N7.1I90N74192N74193N742J1N74398N':- '.•4366N74367N

741SOO TTL

74LSOOH 29

74LS02N .29

74LS04N 35

74LS05N 25

74LS08N 33

74LS10N 35

74LSHN 55

74LST4N 1 00

741S20N 35

74LSJJH 3i

74LS28N 35

741S3DN 35

MIS33N 60

7JLS38N 50

74LS74N 45

74LS75N 65

74LS90N 60

74LS93K 75

7JLS95N 1 00

MLS1Q7N 45

7.1LSH2N 45

74LS113N 45

74L.SI32N 89

74LS136N 50

MLSiaiN 75

74LSI55N 79

74LS157N 1 10

74LSifi2H 1 10

74LS1E3H 1 10

74LS174H 1 J5

74LS190N 1 25

74LS221N 1 25

74LS258N 1 00

74LS367N 89

LI HEAR

M3045 90

CA3081 1 80

CA3082 190

CA30B9 3 40tM30IAN.AH 35

IM305H 87

LM307N 35

I.U308N 1 00

LM309K 1 25

LM32UK-5LM320K 12

■ ■.-■. r.

LM320T-5

LM32Q1-6

LM320M?

LM320T-1S

LM323K-5

LM324N

IM339N

LM340K-5

LM340K-8

LM340K-U

LM340X-'3

LM340-24

LM34QT-S

LM340T-8

LM340! 12

I.M340M5

I.M34UMS

LM1401 24

LM350

LM377

LM379

LM360N

IM381

LM382

LM709H

LM723HN

LM733N

LM741CH

LM741N

LM747HN

LM74BN

LM1303N

LM1304

1.MI305

I.M1307

LMI310

LMI458

LM1S12

LM1889

LM2H1

LM2902

LM3900N

LM3905

LM3909N

MC1458V

NE550N

NE555V

NE556A

NE5G5A

NE566V

N1567V

KEa'OH

7BL05

78L0B

78M05

■ 75108

■ 75491CN1 7W92CN

75494CN

CO4026CD4027CU4028CU4029CD4030CD4035CD4040CB4042CD4043CD4044CD4046C04049CD4050CD4Q51CD4060C04D66CD406BC04069CD407OC04071UD4072CO4073CD4075CD4076C04078CD40B1CO40B2C04116CD4490CD4507C04503CD4510CD45HCD4515CD4516CQ45I8CD4520I CDH27. CD4528CD4553CQ4566CD4583CD4585CO4019274COO74C0474C1Q74C1474C2074C3074C4874C7474C7674C90

2114L450"5 ■! DO

4116 200ns 2 9584116 200nslfl.!0

MM5262 40

MM5280 3 00

MM5320 9 95

MM5330 5 94

PD4I1D-3 4 00

PD4110-4 5 00

P5101L 8 95

4200A 9 95

B2S25 2 90

91L02A 1 50

HD0165 5 u 95

MM57100 J 50

GIAY385001 9 95

MCM6G751A 9 95

1100

3 50

10 00

~1 Sin K!!n>86 pin £(•(].■100 pin I'dnt

1C SOCKETSSolder Tin Low PiolilcPIN I UP PIN 1UP

WIRE WF1AP LEVEL 3

55 key ASCII wyOsara ill

53 key ASCII ■eyooam hiFull) Ji'icmtico

Endoiure Plastic

Mclil Enclosure

it.

77 5060 00

29 9

-,: CLOCKS

-? VM53H 5 50

' -r MV5312 3 90

;u MM5314 3 90

i: MV5369 2 10

-; MM5841 H45

. :' MM5865 7 95

= ^ CT7010 B.95

'S? CI7015 8 95

2°i WM5375AAN 3 90

'■-' :.::■--■:■_-::-,]. : y.j

-?4, 7205 16 50

1 ^l 7207 7 50}° 7208 15 95

; % ;?.a-j 4 95

« O50026CN 3 75

i\ DS0056CN 3 75

'™ WMS31W 2 50

2 45 MICROPROCESSOR

2 35 6502 10 951 10 6504 9 95

3 00 652? 9 9535 6530 9 50

5MH?10 MM;

IB MH720 MH:32 MH*■32763 H;

1 B432 MHz3 5795 MHz

2 0100 MH."

2 097152 MH;

2 4576 MHz

3 2768 MHz5.0688 MH;5 185 MH:

5 7143 MH;

6 5536 MHz

I8 432MH; '

22 1

4 MHl

11 95 KEYBOARD ENCODERS

S12 5017 95105016 50

MC9374C15474C16074CW574C19274C22174C90574C90674C91474C922A ID 0 CONVERTER MC92374C925'4C92674C927

450

22 00

LM3Hi.M3inLM317KLM318

165

aroocj

S701CN

B750CJ 13 95

L0130 9.95

9400CJVF 7 40

ICL7103 9 50

ICL7I07 M 25

CMOS

CO40O0CD4D01CD4002CD4006I.O4D07

C04MB

CO4009C!)40I0CD40HCD4012CD4013C040I4CD4015CD4016CD40WCD40UCO4019CD4020CDJ021CD4022CD4023CD4024CD4025

1802CP (Has 13 95

!802DPpto 17 95

18G1P 9 SD

:UP1B02CD 28 95

MP1B020 35 00

:DP1B16P 7 95

UART/FIFO

AV5-I013 5 50

AV5-10I4 7 50

i AV5-360Q

i AV 5-9100

> AV5 9200

p 74C922

' "4C923

I HD0165-5

I AY5-9400

D Connedors RS232DB25P 3i

OB25S 5:

DE9S

DA15P 2

DA15S 3

Complete Set 9

Kickak3'> Digit LED mul-

LEOS

Red T018 15

Green Yel'ow T018 SO

Jumbo Reo 20

Green 0'inge YtGsw Jumao 25thpltle LEO Mounling Clips BS1 25

CONTINENTAL SPECIALTIES in Hock

MAli'lDD a dinil Fieq. Cli. S149.95

OK WIRE WRAP TOOLS In SlackPanablc Mulllmeler S18.00

Complete line ol AP ProriucU in slock

EncDUor HD0165-5PtllllORICS

MoOd 10 TnoBE'

E.panfltr K,1MnStl 150 Bus

Gtabbtr KtiClock Cilendu Kil2.5 MH; Frequency

3D MHi Frequency

TRANSFORMERS6V 300 ma

■: ', ■..■■;. .'... : . ■

12 6 CI 2 amp

12 6 CT 4 amp

12 6 CT B amp

i? GV C! 600 ma

l?V?M.im ,y.;;i p:un

l?VCT250ma

24V CT 100 ma

10V 1 2 amp asm p^j

!?V 6 amp

12V 50ii ma asm p:u3

12V 1 arm wa« p'ug

ID 15 VAC 8 16VAv.au

01SPLAY LEDS

MAN1 CA 270 2 90

MAN3 CC 125 39

MAN72 74 CA CA 300

DL704 CC 300

DL707DL707R CA 300

plug

9 9 75

limele

Stopwatch KMAuto Clock KiiDigital Clock Kit

89.9526.9517 95

8113BT2081238T248T25BT266T2B

■ !S MOS.MEMORY

2102-12102AL-42102AU2L2104A4

E748

8748 8

8755A

NS2S23

N82SI23

. N82SI26

K82S129

N82SI3I

: N82S136

, NB2S137

CMS577

8223

RESISTORS '. Prafli10 pei type 0325 per type 025100 pe' type 0151000 per type 012350 piece pack

5 per lype 6 75'i win 5% per type 05

OIP Switches

4-posilionS 95 7-posilion I5-oosilion 1 00 B-pOSition I6-posi!ion 1 00

DL727 728DL747 750FND359

;'.; ■ ■ ■■■rN[)503 510FNDBO0BO7

1 111(111 BuDblr

io jiijii axpiii

'■■■J i .it,:. — :..:■■ .

TIL3H Het

MAN3640 CC

MAK4610 CA

'.'•■.'.'.■:

MAM4710

MAN4 740

MANG640

MAH67I0

CA CC 500

CA CC 600

CC 357

CCCA 50O

CC CA 500

CC CA BOO :

CC 40

CA 40CC 40

90

1ANG74

MA1002A C. £ B5

MA1012A l\

102P3 inniloimer l.'t

MA1012A Transformer 2 '■

Moot! 512 S7S5 00Model 920 S8S5 00

PROM Eraser

assembled. 25 PROM capacity S37.50(with timer $69.50). 6 PROM capacity OSriTVUL version $78.50 (with timer $108.50).

Z80 Microcomputer

16 bit I/O, 2 MHz clock. 2K RAM. ROM Bread-board space. Excellent for control. Bare Board$28.50. Full Kit $99.00. Monitor $20.00. PowerSupply Kit $35.00. Tiny Basic $30.00

S-100 Computer Boards

8K Static Godbout Econo IIA Kit 149.0016K Static Godbout Econo XIV Kit 269.0024K Static Godbout Econo XX-24 Kit 414.0032K Static Godbout Econo XX-32 Kit 537.0016K Dynamic RAM Kit 289.00

32K Dynamic RAM Kit 328.00

64K Dynamic RAM Kit 399.DO

Video interface Kit $161.00

Color Video Kit 129.95

81IC Update Master Manual S79.95

Comp. IC data selector. 2 vol. master referenceguide. Over 51.000 cross references. Free updateservice through 1981. Domestic postage S4.75.

Modem Kit $60.00

State of the art, orig., answer. No tuning neces-sary. 103 compatible 300 baud. Inexpensiveacoustic co.upler plans included. Bd. Only$17.00. Article in June Radio Electronics.

Gremlin Color Video Kit $69.95

32 x 16 alpha/numerics and graphics; up to 8colors with 6847 chip; 1K RAM at EOOO. Plugsinto Super EH 44 pin bus. No high res. graphics.On board RF Modulator Kit $4.95

NiCad Battery Fixer/Charger Kit

Opens shorted cells that won't hold a chargeand then charges them up. all in one kit w/fullparts and instructions. $9.95

Rockwell AIM 65 Computer

6502 based single board with full ASCII keyboardand 20 column thermal printer. 20 char, alphanu-meric 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 AIM65 assem. inframe $54.00. Complete AIM65 in thin briefcasewith power supply $499.00. Molded plasticenclosure to fit both AIM65 and power supply$47.50. Special Package Pnce: 4K AIM, 8K Basic,power supply, cabinet $625.00.

AIM65/KIM/VIM/Super Elf 44 pin expansionboard; 3 female and 1 male bus. Board plus 3connectors $22.95.

60 Hz Crystal Time Base Kit S4.40

Converts digital clocks from AC line frequencyto crystal time base. Outstanding accuracy.

Video Modulator Kit $9.95

Convert TV set into a high quality monitor w/oaffecting usage. Comp. kit w/full instruc.

Multi-volt Computer Power Supply

8v 5 amp, ±18v .5 amp, 5v 1.5 amp. -5v.5 amp, 12v .5 amp, -12v option. ±5v, ±12vare regulated. Basic Kit $35.95. Ki! with chassisand all hardware $51.95. Add S5.00 shipping. Kitof hardware $16.00. Woodgrain case $10.00.$1.50 shipping.

RCA Cosmac 1802 Super Elf Computer $106.95

Compare features before you decide to buy anyolher computer. There is no other computer onthe market today that has all the desirable bene-fits of the Super EH for so little money. The SuperElf is a small single board computer that doesmany big things. It is an excellent computer fortraining and for learning programming with itsmachine language and yet it is easily expandedwith additional memory, Full Basic, ASCIIKeyboards, video character generation, etc.Before you buy another small computer, see if itincludes the following features; ROM monitor;State and Mode displays; Single step; Optionaladdress displays; Power Supply; Audio Amplifierand Speaker; Fully socketed for all IC's; Real costof in warranty repairs; Full documentation.The Super EH includes a ROM monitor for pro-gram loading, editing and execution with SINGLESTEP for program debugging which is not in-cluded in others at the same price. With SINGLESTEP you can see the microprocessor chip opera-ting with the unique Quest address and data busdisplays betore, during and after executing in-structions. Also, CPU mode and instruction cycleare decoded and displayed on 8 LED indicators.An RCA 1861 video graphics chip allows you toconnect to your own TV with an inexpensive videomodulator to do graphics and games. There is aspeaker system included for writing your ownmusic or using many music programs alreadywritten. The speaker amplifier may also be usedto drive relays for control purposes.A 24 key HEX keyboard includes 16 HEX keys

plus load, reset, run, wait, input, memory pro-tect, monitor select and single step. Large, onboard displays provide output and optional highand low address. There is a 44 pin standardconnector slot for PC cards and a 50 pin connec-tor slot for the Quest Super Expansion Board.Power supply and sockets for all IC's are in-cluded in the price plus a detailed 127 pg. instruc-tion manual which now includes over 40 pgs. ofsoftware info, including a series of lessons tohelp get you started and a music program andgraphics target game. Many schools and univer-sities are using the Super Elf as a course of study.OEM's use it for training and R&D.Remember, other computers only offer Super Elffeatures at additional cost or not at all. Comparebefore you buy. Super Elf Kit $106.95, Highaddress option $8.95, Low address option$9.95. Custom Cabinet with drilled and labelledplexiglass front panel $24.95. All metal Expan-sion Cabinet, painted and silk screened, withroom for 5 S-100 boards and power supply$57.00. NiCad Battery Memory Saver Kit $6.95.All kits and options also completely assembledand tested.

Questdata, a software publication for 1802 com-puter users is available by subscription for$12.00 per 12 issues. Single issues $1.50, Is-sues 1-12 bound $16.50.

Free 14 page brochure.

of complete Super Elf system.

Moews Video Graphics $3.50. Games and Music$3.00, Chip 8 Interpreter $5.50.

Super Expansion Board with Cassette Interface $89.95

This is truly an astounding value! This board hasbeen designed to allow you to decide how youwant it optioned. The Super Expansion Boardcomes with 4K of low power RAM fully address-able anywhere in 64K with built-in memory pro-tect and a cassette Interlace. Provisions havebeen made for all other options on the sameboard and it fits neatly into the hardwood cabinetalongside the Super Elf The board includes slotsfor up to 6K of EPROM (2708, 2758, 2716 or Tl2716) and is fully socketed. EPROM can be usedfor the monitor and Tiny Basic or other purposes.A IK Super ROM Monitor $19.95 is available asan on board option in 2708 EPROM which hasbeen preprogrammed with a program loader/editor and error checking multi file cassetteread/write software, (relocatable cassette file)another exclusive from Quest. It includes registersave and readout, block move capability andvideo graphics driver with blinking cursor. Break

Quest Super Basic V5.0

A new enhanced version of Super Basic nowavailable. Quest was the first companyworldwide to ship a full size Basic for 1802Systems. A complete function Super Basic byRon Cenker including floating point capabilitywith scientific notation (number range±.17EM), 32 bit integer ±2 billion; multi dimarrays, string arrays; string manipulation; cas-sette I/O; save and load, basic, data and ma-chine language programs; and over 75 state-ments, functions and operations.

points can be used with the register save featureto isolate program bugs quickly, then follow withsingle step. If you have the Super ExpansionBoard and Super Monitor the monitor is up andrunning at the push of a button.Other on board options include Parallel Inputand Output Ports with full handshake. Theyallow easy connection of an ASCII keyboard to theinput port. RS 232 and 20 ma Current Loop forteletype or other device are on board and if .youneed more memory there are two S-100 slots forstatic RAM or video boards. Also a 1K SuperMonitor version 2 with video driver for full capa-bility display with Tiny Basic and a video interfaceboard. Parallel I/O Ports $9.85, RS 232 $4.50,TTY 20 ma l/F $1.95, S-100 $4.50. A 50 pinconnector set with ribbon cable is available at$15.25 for easy connection between the SuperEll and the Super Expansion Board.Power Supply Kit for the complete system (seeMulti-volt Power Supply).

New improved faster version including re-number and essentially unlimited variables.

Also, an exclusive user expandable commandlibrary.

Serial and Parallel I/O included.Super Basic on Cassette $55.00.

Type-N-Talk by Votrax

Text to speech synthesizer with unlim-ited vocabulary, built-in text to speechalgorithm, 70 to 100 bits per secondspeech synthesizer, RS232C interface$345.00.

1802 16K Dynamic RAM Kit $149.00

Expandable to 64K. Hidden refresh w/clocks up to 4MHz w/no wait states. Addl. 16K RAM $25.00Tiny Basic Extended on Cassette $15.00

(Added commands include Stringy, Array, Cas-sette I/O etc.) S-100 4-slot expansion $ 9.95Super Monitor VI.I Source Listing $15.00

Elf II Adapter Kit $24.95

Plugs into Elf II providing Super Elf 44 and 50 pinplus S-100 bus expansion. (With Super Ex-pansion). High and low address displays, stateand mode LED's optional $18.00.

Super Color S-100 Video Kit $129.95Expandable to 256 x 192 high resolution color

graphics. 6847 with all display modes computercontrolled. Memory mapped. 1K RAM expanda-ble to 6K. S-100 bus 1802.8080.8085, Z80 etc.Dealers: Send lor excellent pricing/marginprogram.

Editor Assembler $25.00

(Requires minimum of 4K for E A plus user

source)

1802 Tiny Basic Source listing $19.00

Super Monitor V2.0.2.1 Source Listing $20.00

TERMS: $5.00 min. order U.S. Funds. Calif residents add 6% tax.

$10.00 min. BankAmericard and Master Charge accepted. $1.00 insurance optional.Postage: Add 5%. COD. $10.00 min. order.

FREE: Send for your copy ol our NEW 1981QUEST CATALOG. Include 480 stamp.

Circle 315 on inquiry card.

BYTE October 1981

501

STOCK MARKETNORTH STAR

Double Dens Disk w programs, dataon over 100 stocks

Create, build, maintain data tiles onstock prices

Adjust for splits,stk divs computerelative strength

Portfolio Performed data from diskfiles, gain, rate of gain, yield for eachitem and for total

Evaluate call options risk rewardRequires North Star BASIC DOS, 32KDisk $35 document $4 separate

Lands Associates8005 30th St. S.E,Everett, WA 98205

mLUM PACKARD

The Largest HP Dealer

in Connecticut

Calculators and Computers

Harrington (ompany

METALS DRIVE, P.O. BOX 392SOUTHINGTON, CONN. 06489

An Instnck Full Service Company

Call for discounts

Connecticut Toll Free: 1-800-982-3731

Out of State Call: 203/628-5511

What HEWLETTmLUM PACKARD

68KFORTH

New SYSTEMS LANGUAGE forERG 68-696 CPU andMotorola's KDM board. O/S,Compiler, Monitor, Assembler,Interpreter, Virtual Memory,Screen Editor, DBL PrecisionArithmetic and more. En-hanced FIG-FORTH Vocabu-lary. Environment: stand alone,Bell Lab's UNIX, orWhitesmiths' IDRIS, etc.

$795

EMPIRICAL RESEARCHGROUP, INC.

PO Box 1176

Milton, WA 98354

206-631-4855

Circle 194 on Inquiry card.

Circle 144 on Inquiry card.

CLEAN

NEW FROM SGL WABERThe electricity that powers your personal computersystems is "polluted." Filled with voltage spikes andnoise interference that can cause information loss,equipment malfunction and premature circuit failure.

Protect your data and equipment. Purify your powerwith a new Power Master' Line Monitor PowerConditioner. Just plug in. Free 20 page Catalog, 8models.

ft

POWERMASTER

V^!2_

SGL WABER Electric A division ol SGL Industries, Inc.300 Harvard Ave.'Westville. NJ08093'(609) 456-5400

OPTION

THE STOCK OPTIONSANALYSIS SYSTEM

A complete software packagefor valuing puts and calls andanalyzing all types of optioninvestment positions with yourmicrocomputer (Apple,TRS-80, CP/M systems*).

complete system $25000manual only $15°°

FINANCIALSOFTWARESYSTEMS inc.

L3

505 Gilchrist / 713-696-14 56

College Station, Tx. 77840

'TM TANDY. APPLE. DRI, respectively.

PASSIVESOLARENERGYPROGRAM

Glasslze*—the program toaid you in selecting anappropriate passive glazingarea. Glassize* allows you tobalance aesthetics witheconomics. Package includesdisc for TRS-80 or Apple IIalong with users manualcontaining sizing methods andclimatic data for 200 U. S.cities. $150 postpaid.

The Camroden Company

Route 4 • Box 62Rome, New York 13440

Circle 404 on inquiry card.

Circle 152 on Inquiry card.

Circle 60 on Inquiry card.

ATARI

SS^w

GRAPHICS HARDCOPY

ON: EPSON PRINTERSCENTRONICS 739IDS 445GTRENDCOM

Dumps anything on the screen lo the printer

®

To Order Toll Free1-800-344-7493

In CA. E) for Service (209) 667-2888

AWCROTRONICS, inc..

1125 N. Golden State Blvd.Turlock, California 95380

Circle 207 on Inquiry card.

800400410810850830

820822825483484

16K

16K

Recorder-

DISK

Interface-

Modem

16KRAM.

Printer

Printer

Printer .

The Programmer

The Communicator.

$740.S339.S 59.S449.S169.SI 59.!i 75.S260.S349.S625.!l 55.S330.

Call or write for discount on software.

EMPIRE SYSTEMS CORPORATION18604 Rolling Acres WayOlney, Maryland -20832Call (301) 774-7330

Prices subject to change

Circle 410 on Inquiry card.

UNIPROM

THE VERSATILE EPROM HANDLING SYSTEM

Reads/programs 2704, 2708. 2758, 2508, 2516 (T.I), 2716(single supply), 2532 (T.I.), 2732 (T.I. pinout), and Itel/NEC8755A!

Expandable (or 2732 (INTEL pinout), TMS 2716 (3 supp-ly), 2564 (T.I.).

No personality modules required or additional powersupplies required.

S-100 compalible.

Disk-based software (Z80 only) includes a -MENU"display command, commands usually found in systemmonitors, and versatile CDOS and CP/M compatable diskI/O commands. Also available in a single 2716 EPROM(8080 or Z80) without the ■'MENIT and disk 1/0 commands.

UNIPROM board (A & T) with extensive manual —$245.00.

UNIPROM disk-based software (specify 5.25" or 8"CDOS. 8" CP/M, or 5.25" NORTHSTARCP/M) — $48.00.

UNIPROM EPROM based software, write for flyer.

VISAJMASTER

CER-TEK, INC.

6020 Doniphan Dr.

El Paso, Texas 79932

(915)581-6697

' NORTHSTAR

Circle 63 on Inquiry card.

PRICEBRERKTHROUCH

We've done it again'. As a leader in small computer sales we must constant!],' find new ways to save customers money while offering quality products. Our mostpopular seller, the Apple II Plus, is now available with 64K of user RAM at the unbeatable price of only $1249. This is possible because we manufacture the16K RAM Card that expands the factory Apple II 48K to it's maximum capacity of 64K. The Ram Card allows use of Integer and Applesoft Basic and otherlanguages like Pascal. It's a must for large data bases,- Visicalc. and the Z-80 cards. The card is made from high quality components and has a full one yearwarranty.

64K APPLE II PLUS*

'48 K Apple II Plus with 16K Ram Card

ONLY

16K only $1025 48KDISK II DRIVEDI5K II DRIVE

ONLY

$1089

WITHCONTROLLER CARD

ADD ON

Apple Cards and Hardware

16KRamCardbyCCl 130

Language System w/Pascal 379

SllentypePrinter w/Interface Card 349

Hayes Mlcromodem U 299

Novation Apple-Cat II 339

Vldex Vldeoterm 80 Column w-Graphics 269

Z-80 Softcard by Mfcroaoft 299

lfiKRamCard by Microsoft 159

ABT Numeric Keypad (old or new kybrd) 110

ALF 3 Voice Music Card 239

ALF 9 Voice Music Card 169

Lazer Lower Case Plus + 55

Mlcro-Scl Disk Drives (A40 & A-70) CALL

SSM AIO Serial/Parallel Card A&T 189

Sup-R-Temilnal 80 Column Card 329

SVA ZVX4 Megabyter 8" Disk Controller 589

SVA 2 + 2 Single Den. 8" Disk Controller 345

ThunderClock Plus 119

Sytntec Hl-Res Light Pen 210

Integer or Applesoft Firmware Card 145

Graphics Tablet 619

Parallel Printer Interface Card 135

Hl-Spsed Serial Interface Card 135

Smarterm 80 Column Card 299

Joystick by Keyboard Co 45

Music System {16 Voices) 479

A/D + D/A Interface 289

Expansion Chassis 599

Introl/X-IQ Controller Card 169

Clock/Calendar Card 225

CP8 Multifunction Card 189

Supertalker SD-200 239

Romplus + Card 135

Homwrlter Card 149

Clock/Calendar Module 99

GPIB IEEE-488 Card 249

Asynchronous Serial Interface Card 129

Centronics Parallel Interface Card 99

Arithmetic Processor Card 299

We carry all CCS cards, please call for best prices.

Software for the Apple

VUlcalc 3.3 J69

CCA Data Management 85

DB Master.., 169

WordStar (Apple 80 col. version) 299

Applewrlter ,..,...,... 65

Easywriter 225

Peschtres Business Software CALL

Vislterm ,...,....,«,.. 129

Vlaltrend/Vlslplot .... 219

Real Estate Analyzer 89

Taa Preparer 99

DOS Toolkit 65

T»m Planner 99 '

Dow Jones Portfolio Evaluator 45

Dow Jones Newa 8t Quotes Reporter 85

Apple Fortran 165

Controller Gen. Bus. System ........ 499

Printers

Epson MX-80 CALL

Anadex 9500/9501 «r/2K Buffer 1299

C. Itob StanvriteT 25 CPS 1499

C. Ilho Starurrtter 45 CPS 1899

Epson MX-70 CALL

Epson MX-80 F/T CALL

Paper Tiger IDS 445 699

Paper Tiger IDS 460 949

Paper Tiger IDS-560 1249

Sllentype w/Apple II interface card 349

Qlime Sprint 5/45 2495

TOLL FREE ORDER LiNE

800-854-6654

California and outsideContinental US

(714) 698-8088TELEX 695000 BETA CCMO

Video Monitors

Amdek/Leedex Video 100 12" B&W 139

Amdek (Hitachi) 13" Color 359

NEC 12" Green Phoapher Screen CALL

NEC 12" RGB Hl-Rea Color CALL

Panasonic 13" Color .449

Sanyo 9" BslvV 185

Sanyo 9" Green Phoapher Screen C ALL

Sanyo 12" BSW 269

Sanyo 12" Green Phoapher Screen . 285

Sanyo 13" Color tv/excellent resolution 449

Atari Personal Computer

I

<«

ATARI 800 16K $ 749

Atari 400 16K 349

410 Program Recorder 65

810 Disk Drive 449

815 Dual Disk Drive (Dbl. Den.) 1295

822 Thermal Printer 349

850 Interface Module 159

16KHam Memory Module 149

16K Ram Memory Module (by ConComp) . .89

NEC Microcomputer

PC-8001A 32K Ram Computer CALL

PC-8012A I/O Unit w/32K Ram CALL

PC-8031A Dual Mini-Disk Drive Unit CALL

Please write for more information about the NEC computer.

Ordering information: Phone orders using VISA, MASTERCARD.AMERICAN EXPRESS, DINER'S CLUB, CARTE BLANCHE, hankwire transfer, cashier's or certified check, money order, or personalcheck (allow len days lo clear). Unless prepaid with cash, please add5% for shipping, handling and insurance, (minimum 5.00). Callfornla residents add 6% sales tax We accept CODs OEM's. Institutionsand corporations please send for a written quotation. All equipmentis subject to price change and availability without notice. All equipsment is new Bnd complete with manufacturer's warranty (usually 90days). Showroom prices may differ from mail order prices.

Send Orders to:

(MjO§QOGDQ(Mr

G®00Q[pQ!]{,©[?§ Mall Order

8314 Parkway Drive

La Mesa, California 92041

Circle 103 on inquiry card.

scotch

®

Buy the finest in data recordingproducts from your PISKDNNECTION.Price 10

S'A" (soft, 10 or M hard) $ 27°°8" (single side/density) 27 °°

8" (reversible, sgl. density) 40 °°

8" (sgl. side. dbl. density) 35 °°

8" (dual side, dbl. density) 40 °°

MC or VISA, add I °°

Postage and handling included' Send check, MO. MC or VISA to,

DISKONNECTION

POB. 538

Mpls. Minnesota 55440

'612/871-1677 before noon CST

STATISTICALSOFTWARE

ELF — Stepwise regression, fac-tor analysis, correlation coeffi-cients, crosstabs, simple statistics,t-tests, ANOVA, stepwise discrimi-nant analysis, all BASIC transfor-mations and more. $200.00

TWG/ARIMA - Box-Jenkins forseasonal and non-seasonal models,identification, estimation and fore-casting. Introductory Price:$250.00.

Each includes a databasemanager, numeric software key-pad, and is menu-driven. Each re-quires an Apple II with Applesoft,48K, and DOS 3.3.

For further information, write

lit. TVutcAtiuOui tyuwji

3907 Lakota Road

P.O. Box 10114

Alexandria, VA 22310

"Apple II and Applesoft are trademarks ofthe Apple Computer Company

MULTIBUS for SALE:

SBC86/12A $1200

SBC 80/30 $ 450

SBC 064 $ 900

SBC 604 $ 85

SBC 614 $ 85

BLC556 $ 175

Much more in stock. We buy/swap/sell any/all computer systems. Add2% for shipping/handling.

Oracle Electronics& Trading Co., Inc.

467 Hamilton Ave., Suite 22

Palo Alto, CA 94301

(415) 321-7650

Circle 129 on inquiry card.

Circle 366 on inquiry card.

Circle 279 on Inquiry card.

| MAILING LABELS ETC.

Continuous Form Fanfold Pin-FeedWhite & Colored Printout Paper,STOCK & CUSTOM Office Forms,File Cards, Rubber Stamps, MarkingDevices, Offset Printing, DoubleCopy, Price Marking & Roll Labels,Pressure Sensitive, Cheshire, Plainor Gummed Back & Heath SensitiveMailing Labels etc. at LOWESTPOSSIBLE PRICES & Fast Delivery,

SAMPLE PRICES: (Postpaid)

3% x 15/16 Pressure Gummed

Label s Sensitive Back

5,000 .... $ 16.50 .... $13.7510,000 .... $31.50 .... $26.7515,000 .... $46.50 .... $39.5020,000 .... $60.00 .... $51.25

Conn. Customers Please Add SalesTax. Catalog $1.00 (Refundable) orFREE with your order.

HANDICRAFTS DePt. BT

24 Winter St., Stamford, Ct. 06905

^0 S-100DOUBLE HEIGHT

10" HIGH PROTOTYPE BOARD

• Regulators provide „

5V @ M, ± 12V @ 1A

■ Accepts over 120 IC'splus 3M-type connectors

> Heavy power distribution

with 28 distributed ftf "ITH'M-

0.1 ufd caps *1"'™

13" HIGH EXTENDER CARD

• Scope probe hanger on

> Ground trace betweensignal lines

• Heavy power traceswith removable jumpersfor current measurement

n

Inner AccessCorporation

Box 888

Belmont, CA 94002

(413)591-8295

- Boards meetIEEE-696 compliance HHspecifications

68000

ERG68-6.96 68000 CPU in pro-duction. Meets or exceedsIEEE696 S-100 standard.

$1995

Available software: Z80emulator, 68K FORTH sys-tems language, WhitesmithsUNIX-like IDRIS—O/S with Cor Pascal compilers.

Integrated 6800 systems alsoavailable.

EMPIRICAL RESEARCHGROUP, INC.

PO Box 1176

Milton, WA 98354

206-631-4855

Circle 163 on inquiry card.

Circle 176 on Inquiry card.

Circle 145 on inquiry card.

$ GET YOUR SHARE $

Join the thousands of winners who have builton their computer interest to create a success-ful data processing-based business, and:SHARE IN THE MINI/MICROPROCESSING BOOMRead this exciting new book:MAKING IT IN DATA PROCESSING -ON YOUR OWN IN THE EIGHTIES

Written by experts in the computer business,this book contains all you need to get "started,including:

• How to locate manufacturers who will helpfinance your new venture.

• What types of business are available andare best for you.

• Actual sources of Venture Capital lookingfor new businesses.

• Complete guides to pricing, sales promo-tion, advertising, publicity, and marketing.

• Dozens of sources of information to helpyou build your business.

To order, just clip this ad and send with only$19.95 to:

THE SEABIRD PRESS

PO Box 461, Lexington, MA 02173Full 30 day money back guarantee

PROBLEM:

How to mate your CP/M- or ISIS-

system to the

Z-8000

(without losing all your present capabilities)

SOLUTION:

■HMa'K^ is the software connection which permits^_ t#V ^"8000 applications to run under your cur-rent operating system, resulting in portable16-bit software which runs under CP/M or ISIS! And ZEXis user-configured for any Z-8000 alternate bus master, sothat it can support your prototype hardware, as well ascommercially available Z-8000 boards.

^m m £% is a complete Z-8000 Development Package,f t\^^ which includes a powerful relocatablecross assembler (ZAS), a flexible object taskbuilder (ZLK). and an absolute object loader (ZLD), as wellas the ZEX run time module. The package was developedspecifically for the Z-8000, and supports the completeZilog instruction syntax for both the Z8001 and Z8002, in-cluding support for mixed segmented and non-

segmented code

WESTERNWARES

ZAS Package cpim S395ISIS-II ..S495

Manual Only $25

Supplied on Single Density 8" Disk

BoxC Norwood, CO 81423 (303)327-4898

Computer compatiblePaper Tape Punch

From Addmaster Corporation — a self-contained paper tape punch which makes5, 6, 7 or 8-level tapes at speeds up to 50cps. Parallel data keyboard inputs, manualback space, tape low lamp, TTL level com-patible, 5-8 level (ANSI), optional RS232CI/O serial port are* features. Maximum 8"reel, standard hub. (1000 feet). Optionalattachment for standard fanfold tape.Contact Addmaster Corporation, 416 Juni-pero Serra Drive, San Gabriel, CA 91776.Telephone: (213) 681-3098

Circle 430 on inquiry card.

Circle 391 on inquiry card.

Circle 7 on inquiry card.

Here we grow again H!

Grand Opening Sale

We're celebrating the latest addition to Jade's Retail Division - our newstore located in Woodland Hills at 21800 Ventura Blvd.

New from Jade

The Bus Probe

Inexpensive S-100 Diagnostic Analyzer

So your computer is down. And you don't have anoscilloscope. And you don't have a front panel...You're not alone ■ most computers have theiroccasional bad days. But without diagnosticequipment such as an oscilloscope (expensive!) ora front panel (expensive!), it can be very difficult topinpoint the problem. Even if you have anextender board with a superfast logic probe, youcan't see more than one signal at a time. You'restuck, right?

Not anymore; Jade is proud to offer our cost-effective solution to the problems mentionedabove: THE BUS PROBE.Whether you're a hobbyist with a cantankerouskluge or a field technician with an anxiouscomputer owner breathing down your neck, you'llfind THE BUS PROBE speeds your repair timeremarkably. Just plug in THE BUS PROBE andyou'll be able to see all the IEEE S-100 signals inaction. THE BUS PROBE allows you to seeinputs, outputs, memory reads and writes,instruction fetches, DMA channels, vectoredinterrupts, 8 or lfi bit wide data transfers, plus thethree bus supply voltages.

An on-board pulse generator can providerepetitive resets, interrupts, or wait states, fortrouble shooting.

TSX-200B Bare board $59.95

TSX-200K Kit $119.95

TSX-200A A&T $149.95

II vfn

II-t^^^i^UH

>i' r

NEC

■I MHz Z-80 CPU. HO .x 2.5 display with graphics and 8colors, 32K RAM. Z4K ROM. parallel serial, cassetteinterfaces, upper Inner case, numeric keypad. Hi specialfunction keys, uses CP M 2.2.

NKC-8001A II2K CPU'keyboard .. $1095.00NEC-8012A I/O with 32K RAM ... $695.00

NEC-8031A Dual dish unit $1095.00

VDM-65I200 12" green CRT $269.95

NEC-1202D Hi-res RGB color CRT $1045.00VDC-651212 12" color monitor .... $479.95NEC-9010S CP/M2.2forNEC .... $150.00NEC-90005 Gen. accting softwr ... $375.00

Inter sell

Sellum I

NEC Spinwriter w/ Intelligent Controller

m

Standard serial, Centronics parallel, and currentloop interfaces • Selectable baud rates 50 to 19,200

• Automatic bidirectional printing • Logicseeking • 650 character buffer with optional 16Kbuffer • 55 characters per second print speed •Comes with vertical forms tractor, ribbon, thimbleand cable • Diablo compatible software •Available with or without optional front panel

PRD-55511 IK no front panel .... $2795.00

PRD-55512 16K no front panel ... $2895.00

PRD-55515 IK w front panel $2995.00

PRD-55516 WKw/front panel ... $3095.00

Intersell NEC 3500Q

Intersell has announced that, available inSeptember, they will offer a version of the newNEC Model 3500Q Spinwriter (30 cps) that willbring to the customer the same standard featuresas the Sellum I (except the tractor assembly whichis optional on the 3500Q) but incorporating theadded features of the NEC Model 3500Q

PRD-55351 3500Q IK $1995.00

PRD-55352 :i500Q 16K $2095.00

PRA-55100 Deluxe tractor option .. $300.00

JADE

Disk Sub-Systems

Shugart, Siemens, Qume

Handsome metal cabinet with proportionallybalanced air flow system • Rugged dual drivepower supply • Power cable kit • Power switch,line cord, fuse holder, cooling Ian • Never-Marrubber feet • All necessary hardware to mount 2-H" disk drives, power supply, and fan • Does notinclude signal cable

Dual 8" Subassembly Cabinet

END-000420 Bare cabinet $59.95

END-000421 Cabinet kit $225.00

END-000431 A&T $359.95

8" Disk Drift- SubsystemsSingle Sided, Double DensityEND-000423 Kit w 2 FDlOO-SDs . $924.95END-000424 A& T w'2 FDlOO-SDs $1124.95END-000433 Kit w/2 SA-SOlRs ... $999.95END-000434 A & Tw'2 SA-HOIRs $1195.00

H" Dish Drive SubsystemsDouble Sided, Double Density

END-000426 Kit w/2 DT-8s $1224.95

END-000427 A&Tw 2 DT-Ss ... $1424.95END-000436 Kit u</2 SA-KoIRs .. $1495.00END-000437 A&Tw 2 SA-85lRs $1695.00Circle 188 on inquiry card.

\ -Specialkk Sale Price-

QUME DT-8

8" Double-Sided, Double-Density Disk Drive

1 Drive ... $524.95 each

2 Drives . $499.95 each10 Drives $479.95 each

Jade Part Number MSF-750080

SIEMENS 8"

8" Single-Sided, Double-Density Disk Drive

1 Drive ..

2 Drives10 Drives

$384.95 each$349.95 each$324.95 each

Jade Part Number MSF-201120

Shugart 801R

8" Single-Sided, Double-Density Disk Drive

1 Drive ... $394.95 each

2 Drives . $389.95 each

Jade Part Number MSF-10801R

MPI B-51

5'/i" Single-Sided, Double-Density Disk Drive

1 Drive ..

2 Drives10 Drives

$234.95 each$224.95 each$219.95 each

Jade Part Number MSM-155100END-000213 Case & potter supply $74.95

Micro- Sci

Apple Disk Drives

Increased Capacity - Decreased Price

40 or 70 track drives • operates with DOS 3.2 and3.3, Language System, and the Z80 Softcard • 40and 70 track drives may be mixed on your Apple II• With two 40 track drives you get a 12.6% increasein capacity, 300% improvement in track-to-trackaccess, and save about 15% • With two 70 trackdrives instead of four 35 track drives you get thesame capacity, 300% improvement in track-to-track access time, and save about 45%.

IOD-2340A A-40 with cable $399.95

IOD-2370A A-70 with cable $529.95

IOD-2300A Micro-sci controller .... $89.95

Grand Opening Sale

****** San Diego ****** Hawthorne ****** Woodland Hills ******

Printers

Accessories for Apple

Single Board Computers

Dual-Mode 200 - Malibu

200 CPS/9 x 9 matrix or 70 CPS/19 x 18 matrix for letterquality, stores up to 12 different fonts, hi-res dot graphics,single sheet and tractor feed, RS-232C and parallel interfacesPRM-35200 Dual-Mode 200 $2695.00

BEST BUY in PRINTERS - Epson

MX-70 132 column, HO CPS. 5 x 7 dot matrix, adjustable

tractor feed, & graphics

PRM-27070 List $459 $399.95

MX-80 132 column, HO CPS. bi-directional/logic seekingprinting, 9 x 9 dot matrix, adjustable tractor feed. & 64graphics charactersPRM-27080 List $645 $474.95

MX-80FT same us MX-80 with friction feedPRM-27082 List $745 $574.95

MX-100 233 column, correspondence quality, ultra-highresolution graphics, up to 15" paper, friction feed &removable- adjustable tractor feed. 18 x!8 dot matrix, 80CPS. programmable forms handlingPRM-27100 List $945 $795.00

PRA-27084 Serial interface $69.95

PRA-27088 Serial inlf & 2K buffer .. $144.95

PRA-27081 Apple card $74.95

PRA-27082 Apple cable $22.95

PRA-27086 IEEE 488 card $52.95

PRA-27087 TKS-80 cable $32.95

PRA-27085 Graftrax II $95.00

PRA-27083 Extra ribbon $14.95

Accessories for TRS-80

DISK DRIVES for TRS-80

23% more storage, 8 times faster. 40 track with free patch, 120

day warranty.

MSM-12410C Save $125.00 !!! $325.00

8" DISK DRIVES for MODEL II

2 double density drives with cabinet, power supply, & cables

END-000433 Kit $1050.00

END-000434 Assembled $1250.00

WCA-5036A Cable (required) $29.95

16K Atari ... $359.95

ATARI 800 - Atari

Complete personal computer with high rgraphics, built-in RF modulator, -1 controllerspeaker. 16K RAM & HK ROM

SYO-2080A 16K Atari 800

Atari 800 with 32K of RAM ....

^solution colorports, internal

$759.95$799.95$849.95$359.95$595.00$1395.00$199.95$69.95

Atari 800 with 48K of RAM ....

SYO-2040A 16K Atari 400

MSM-330810 Disk drive

MSM-330815 Dual drive

IOX-5050A 850 interface

MEX-16853K IRK RAM module

\ SFI-241011005 Visicalc

.. $184.95

16K MEMORY UPGRADE

Add WK of RAM to your TRS-80, Apple, or Exidy in justminutes. We've sold thousands of these 16K RAMupgrades which include the appropriate memory chips (asspecified by the manufacturer), all necessary jumperblocks, fool-proof instructions, and our 1 year guarantee.

MEX-16100K TRS-80 kit $25.00

MEX-16101K Apple kit $25.00

MEX-16102K Exidy kit $25.00

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-80 & 6502, more than doubles thepower & potential of your Apple, includes Z-801* CPU card,CP M 2.2. & BASIC-80CPX-30800A A&T $299.95

APPLE CLOCK - Cal Comp Sys

Real time clock w/battery back-upIOK-2030A A&T $109.95

8" DISK CONTROLLER

New from Vista Computer, single or double sided, single ordouble density, compatible with DOS 3.2/3.3. Pascal, & CPU2.2, Shugart & Qume compatibleIOD-2700A A&T $499.95

8" DRIVES for APPLE

Controller, DOS, two 8" double densisty drives, cabinet,power supply, & cables

Special Package Price Kit $1399.95

PRINTER INTERFACE - CCS.

Centronics type 1/0 card w/ firmwareIOI-2041A A&T $99.95

AIO, ASIO, APIO - S.S.M.

Parallel & serial interface for your Apple (see Byte pg 11)

IOI-2050K Par & Ser kit $139.95

IOI-2050A Par & Ser A & T $169.95

IOI-2052K Serial kit $89.95

IOI-2052A Serial A&T $99.95

IOI-2054K Parallel kit $69.95

IOI-2054A Parallel A&T $89.95

A488 - S.S.M.

IEEE 488 controller, uses simple basic commands,includes firmware and cable, 1 year guarantee, (see AprilByte pg 11)IOX-7488A A&T $399.95

CPS MULTICARD - Mtn. Computer

Three cards in one! Real time clock calendar, serial interface,

& parallel interface - all on one card.

IOX-2300A A&T $199.95

Apple-CAT - Novation

Software selectable 1200 or 300 baud, direct connect, auto-answer/auto-dial, auxiliary 3-wire RS232C serial port forprinter.IOM-5232A Save $50.00!!! $325.00

AIM-65 - Rockwell

6502 computer with alphanumeric display, printer, &keyboard, and complete instructional manuals

CPK-50165 IK AIM $424.95

CPK-50465 4K AIM $499.95

SFK-74600008E 8K BASIC ROM ... $99.95SFK-64600004E 4K assembler ROM $84.95

PSX-030A Power supply $64.95

ENX-000002 Enclosure $54.95

■IK AIM. 8K BASIC, power supply. & enclosureSpecial package price $675.00

Z-80* STARTER KIT - SD Systems

Complete Z-80* computer with RAM. ROM. 1 O, display,keyboard, manual, and kluge area.

CPS-30010K Kit $369.95

CPS-30010A A&T $459.95

SYM-1 - Synertek Systems

Single hoard computer with IK of RAM. -IK of ROM. keypad.LEI) display. 20ma & cassette interface on board.CPK-50020A A&T $249.95

Video Terminals

VIEWPIONT-ADDS

Detachable keyboard, serial RS232C interface, baud ratesfrom 110 to 19.200. auxiliary serial output port. 21 x 80display,tillable screen, international character setVDT-501210 Sale Priced $639.95

TELEVIDEO 950

Detachable keyboard, split screen with line lock, etched CRT.programmable function keys, on-screen status line, bufferedauxiliary port. 14 x 10 dot matrix, self test, serviced nation-wide by General ElectricVDT-901250 List $1195.00 $995.00

Video Monitors

Leedex / Amdek

Reasonably priced video monitorsVDM-801210 Video 100 12" B&W .. $139.95VDM-801230 Video 100-80 12" B& W $179.95VDM-801250 12" Green Phospor .... $169.95VDC-801310 13" Color I $379.95

12" COLOR MONITOR - NEC

Hi-res monitor with audio & sculptured caseVDC-651212 Color Monitor $479.95

12" GREEN SCREEN - NEC

20 MHz, P31 phosphor video monitor with audio,exceptionally high resolution ■ A fantastic monitor at avery reasonable priceVDM-651200 12" monitor $269.95

EPROM Erasers

EPROM ERASERS

L.S. Engineering UV eraser for up to -18 EPROMsXME-3200 A&T $39.99

Spectrnnics hi intensity industrial eraser

XME-3100 Without timer $69.50

XME-3101 With timer $94.50

Grand Opening Sale

Circle 187 on inquiry card.

****** San Diego ****** Hawthorne ****** Woodland Hills ******

S-100 PROM Boards

S-100 Memory

S-100 CPU

PB-l - S.S.M.

2708. 2716 EPROM board with built-in programmer

MEM-99510K Kit $154.95

MEM-99510A A&T $219.95

PROM-100 - SD Systems •

2708. 2716. 2732, 2758, & 2516 EPROM programmer

MEM-99520K Kit $219.95

MEM-99520A Jade A&T $269.95

EPROM BOARD - Jade

16K or 32K uses 2708's or 2716's, IK boundary

MEM-16230K Kit $79.95

MEM-16230A A&T $119.95

S-100 Video

VB-3 - S.S.M.

80 characters x 24 lines expandable to80x 48 for a full pageof text, upper & lower case, 256 user defined symbols, 160 x192 graphics matrix, memory mapped, has key boardinput.

IOV-1095K 4 MHz kit $349.95

IOV-1095A 4 MHz A&T $439.95

IOV-1096K 80 x 48 upgrade $39.95

VDB-8024 - SD Systems

80 x 24 I/O mapped video board with keyboard I/O, andon-board Z-80 A*.

IOV-1020K Kit $399.95

IOV-1020A Jade A&T $459.95

VIDEO BOARD - S.S.M.

64 characters x 16 lines, 128 x 48 matrix for graphics, fullupper/lower case ASCII character set, numbers, symbols,and greek letters, normal/reverse/blinking video, S-100.

IOV-1051K Kit $149.95

IOV-1051A A&T $219.95

IOV-1051B Bare board $34.95

Motherboards

ISO-BUS - Jade

Silent, simple, and on sale - a better motherboard6 Slot (SW x 8*/h")

MBS-061B Bare board $19.95

MBS-061K Kit $39.95

MBS-061A A&T $49.95

12 Slot (9V x 8W)

MBS-121B Bare board $29.95

MBS-121K Kit $69.95

MBS-121A A&T $89.95

18 Slot (14'/y x 8¥n")

MBS-181B Bare board $49.95

MBS-181K Kit $99.95

MBS-181A A&T $139.95

Mainframes

MAINFRAME - Cal Comp Sys

12 slot S-WO mainframe with 20 amp power supply

ENC-112105 Kit $329.95

ENC-112106 A&T $399.95

DISK MAINFRAME - N.P.C.

HoW« 2 K" drives and a 12 slot S-100 system. Attractive

metal cabinet with 12 slot motherboard & card cage, power

supply, dual fans, lighted switch, and other professional

features

ENS-112325 with 25 amp p.s $699.95

MEMORY BANK - Jade

4 MHz. IEEE S-100, bank selectable, 8 or 16 bit.expandable from 16K to 64K

MEM-99730B Bare board $49.95

MEM-99730K Kit, no RAM $199.95

MEM-16730K 16K kit $219.95

MEM-32731K 32K kit $239.95

MEM-48732K 48K kit $259.95

MEM-64733K 64K kit $279.95

Assembled & tested add $50.00

EXPANDORAM II - S D Systems

4 MHz RAM board expandable from 16K to 64K

MEM-16630K 16Kkit $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

64K RAM - Calif Computer Sys

4 MHz bank port / bank byte selectable, extendedaddressing, I6K bank selectable, PHANTOM line allowsmemory overlay, 8080 / Z-80 / front panel compatible.MEM-64565A A&T $575.00

64K STATIC RAM - Mem. Merch.

64K static S-100 RAM card, 416K banks, up to 8 MHzMEM-64400A A&T $825.00

32K STATIC RAM - Jade

2 or 4 MHz expandable static RAM board uses 2114L's

MEM-16151K UK 4 MHz kit $169.95

MEM-32151K 32K 4 MHz kit $299.95

Assembled & tested add $50.00

16K STATIC RAM - Mem Merchant

4 MHz 16K static RAM board, IEEE S-100, bank selectable,Phantom capability, addressable in 4K blocks, "disable-able"in IK segments, extended addressing, low powerMEM-16171A A & T $174.95

S-100 Disk Controller

DOUBLE-D - Jade

Double density controller with the inside track, on-board Z-80A*. printer port, IEEE S-100, can function on aninterrupt driven buss

IOD-1200K Kit $299.95

IOD-1200A A&T $375.00

IOD-1200B Bare board $59.95

VERSAFLOPPY II - SD Systems

New double density controller for both 8" & 5'/i"

IOD-1160K Kit $339.95

IOD-1160A A&T $379.95

DOUBLE DENSITY - Cal Comp Sys

5'A" and 8" disk controller, single or double density, withonboard boot loader ROM. and free CP/M 2.2* andmanual set.IOD-1300A A&T $369.95

■PS

CB-2 Z-80 CPU - S.S.M.

2 or 4 MHz Z-80 CPU board with provision for up to 8KofROM or 4K of RAM on board, extended addressing, IEEES-100, front panel compatible.

CPU-30300K Kit $239.95

CPU-30300A A&T $299.95

2810 Z-80* CPU - Cal Comp Sys

2/4 MHz Z-80A* CPU with RS-232C serial I/O port andon-board MOSS 2.2 monitor PROM, front panel compatible.CPU-30400A A&T $269.95

SBC-200 - SD Systems

4 MHz Z-80 *CPU with serial & parallel I/O ports, up to 8Kof on-board PROM, software programmable baud rategenerator, IK of onboard RAM, Z-80 CTC.

CPC-30200K Kit $339.95

CPC-30200A Jade A&T $399.95

THE BIG Z* - Jade

2 or 4 MHz switchable Z-80* CPU with serial I/O,accomodates 2708, 2716, or 2732 EPROM, baud rates from75 to 9600

CPU-30201K Kit $139.95

CPU-30201A A&T $189.95

CPU-30200B Bare board $35.00

Novation Cat Modem

IOM-5200A List price $189.95 .7!*7. $125.00

D-CAT 300 baud, direct connect modemIOM-5201A Special sale price $169.95

AUTO-CAT Auto answer/origiate. direct connectIOM-5230A Special sale price $239.95

SMARTMODEM - Hayes

Sophisticated direct-connect auto-answer/auto-dial modem,touch-tone or pulse dialing, RS-232C interface, programmableIOM-5400A Smartmodem $269.95

Place Orders Toll Free

S-100 I/O

S.P.I.C. - Jade

Our new I/O card with 2 SIO's, 4 CTC's, and 1 PIOIOI-1045K 2 CTC's, 1 SIO, 1 PIO .. $179.95 I

IOI-1045A A&T $239.95 Z

IOI-1046K 4 CTC's, 2 SIO's, 1 PIO $219.95 I

IOI-1046A A&T $299.95 Z

IOI-1045B Bare board w/ manual ... $49.95 I

1/0-4 - S.S.M.

2 serial I/O ports plus 2 parallel I/O ports j

IOI-1010K Kit $179.95 ■

IOI-1010A A&T $249.95 ■

IOI-1010B Bare board $35.00 I

Continental U.S.

800-421-5500

Inside California800-262-1710

For Technical Inquires or Customer Service call:

213-973-7707

Computer Products

4901 W. Rosecraris, Hawthorne, Ca 90250

TERMS of SALE: Cash, checks, credit cards, orPurchase Orders from qualified firms and institutions.Minimum Order $15.00, California residents add 6%tax. Minimum shipping & handling charge $.3.00.Pricing & availibility subject to change

INTELLIGENT VIDEO I/O FOR S-100 BUS

VIO-X

The VIO-X Video I/O Interface for theS-100 bus provides features equal to mostintelligent terminals both efficiently andeconomically. It allows the use of standardkeyboards and CRT monitors in conjunc-tion with existing hardware and software. Itwill operate with no additional overhead inS-100 systems regardless of processor orsystem speed.

Through the use of the Intel 8275 CRTcontroller with an onboard 8085 processorand 4k memory, the VIO-X interface oper-ates independently of the host system andcommunicates via two ports, thus elimi-nating the need for host memory space.The screen display rate is effectively 80,000baud.

The VIO-X1 provides an 80 character by25 line format (24 lines plus status line)using a 5 X 7 character set in a 7 x 10 dotmatrix to display the full upper and lowercase ASCII alphanumeric 96 printablecharacter set (including true descenders)with 32 special characters for escape andcontrol characters. An optional 2732character generator is available whichallows an alternate 7X10 contiguousgraphics character set.

FULCRUM

COMPUTER PRODUCTS

The VIO-X2 also offers an 80 characterby 25 line format but uses a 7 x 7 characterset in a 9 x 10 dot matrix allowing high-resolution characters to be used. Thismodel also includes expanded firmware forblock mode editing and light pen location.Contiguous graphics characters are notsupported.

Both models support a full set of controlcharacters and escape sequences, includ-ing controls for video attributes, cursorlocation and positioning, cursor toggle,and scroll speed. An onboard Real TimeClock (RTC) is displayed in the status lineand may be read or set from the hostsystem. A checksum test is performed onpower-up on the firmware EPROM.

Video attributes provided by the8275 in the VIO-X include:

• FLASH CHARACTER

• INVERSE CHARACTER

• UNDERLINE CHARACTER or

• ALT. CHARACTER SET

• DIM CHARACTER

The above functions may be toggledtogether or separately.

The board may be addressed at any portpair in the IEEE 696 (S-100) host system.Status and data ports may be swapped ifnecessary. Inputs are provided for parallelkeyboard and for light pen as well as anoutput for audio signalling. The interruptstructure is completely compatible withDigital Research's MP/M ®.

Additional features include:

HIGH SPEED OPERATION

PORT MAPPED IEEE S-100

INTERFACE

FORWARD/REVERSE SCROLL or

PROTECTED SCREEN FIELDS

CONVERSATIONAL or BLOCK

MODE (opt)

INTERRUPT OPERATION

CUSTOM CHARACTER SET

CONTROL CHARACTERS

ESCAPE CHARACTER

COMMANDS

INTELLIGENT TERMINAL

EMULATION

TWO PAGE SCREEN MEMORY

VIO-X1 - 80 X 25 5 X7 A & T

Conversational ModeVIO-X2 - 80 X 25 7 x 7 A & T

Conversational & Block Modes

-CED

$295.00$345.00

VIO-X S-100 I/O INTERFACE

Distributed by:

WW COMPONENT SUPPLY INC.

1771 JUNCTION AVENUE • SAN JOSE, CA 95112 • (408)295-7171

Circle 395 on inquiry card.

o

CaIIFornia DIgitaI

Post Office Box 3097 B • Torrance, California 90503

FBEE PLASTIC LIBRARY CASE INCLUDED WITH THEPURCHASE OF EVERY BOX OF DISKETTES

:- label* ft J- CftlUoml I Digital by one of■ •■■ respected producers of magnetic media. (:> kette -.- certified doable density at -JO!■■ m.;:i!■■■ extended media life each dia-m tnul mured with .1 reinforced hub-hole.Mite, . p| istic hhi-.irv '--.-.se Is includedverv box of diskettes. MMD-CDMOI)U0)• specify computer or required sectors.

■II. BOX

Ten boxes $22.75

MINIDISKS |TES Box

mores 3401 (37.00

rh.iiini S2SWIX10] 88.00

One hundred boxes $21.50

EIGHT INCH Scotch bax 10 bx. Oysan box 10 b.x. MUX box 10 i,

Soili iWe/elasla den. T«-0 i3J. 5a:i. 3740/1 svj. S47. aooo s- 5. 5.::

Sin. 1- tide/double den. ?■( 1 -0 46. 43. 3740/id 7f>. ta. jouo 3". 3!

Single side/32 sector 740-32 as. 33. na. na.

Double side/ double O. 743-0 r,5. :,i: na. 3U5 40. 41

SCOTCH brand bead cleaning Wt. $24.95 MMA-CK(jH8) please specify S1/1 B"Price iv .il.ibl.- on request for: tape, cartridges, diskpacks, volunin dtstcelt'

26 MegabyteHard Disk Drive

from

George Morrow's

Thinker ToysS3495

I I ■..."-■ 1 ColliruHec

MIGhord diet ControlleiSwitchboard Interface

MEMOREX $

8"DISKETTES

25

MEMORY ■ ,

64K DYNAMIC$11.95

4164 100-s9.75

16K DYNAMIC

$2.io

4116 100''1.85

16K STATIC

$13.95

2167 200ns.

2716EPR0M$4_95

100.M.50 1K-M.00

STATIC

i2+

■1W.02 450ns.

211.02 L'fiOns2114L4 4f)0ns2114L3 :100ns4044-4 450ns•1014-2 2S0ns5257-3 SOOns

1. 191. 49

3. 95

4. 25

4. 95

5. 501. 47

1. 051.452.95

3. 75

4. 504.954. 25

.99. 39. 75.00. 25. 50.05

EPRQM

270U 450ns

2715 5V.

2716 tri-volt27 32 bllul

2532 TI27S4

4.95 4.50 3.75

4. 95 4. 50 4. 00

9.95 9.00 8.25

J. 00 3.50 3.09

21.30 19.00

2.754.004. 353.75

3.25

7.50

Your Choice

direct connect

MODEM *169

I'lther of these twi-

ll.- 1 I,... r-;..l lioia Systems n> n.l' 1

31. I ...I, 1.. Jtllh H. II 111 .. .'

Ii ;■ . . too (■■.-■.■■!■• I Iron

roxlti .■. to ":.''. >■ *■ !■ roeuptlrle.

Universal Data Auto Answer 103LPJ *219Novation Auto Cat RS232 *239

BSR

SYSTEM

X-10

The new BSR timer runsappliances while your awistiuj: System X-10 clevicBSIt Timer eight chtuineMaster control consoleUltrasonic Controller

ApsUance Module r.oo w. $13.85Lamp Module 300 Watts 13-85

NEW lull control wall switch 14.50

S-100 Mother Board $35

QuietBuss

SWITCHES

AS !:S

n 1.3H i. is

CONNECTORS

.158" Centers (standard]22/44 Kim Evelct38/72 Digital Group S/T38/73 Diglta] Croup W/W43/86 Motorola eeoosn*43/HB Molo. (iltOO WAV

5.606.80

7.00

I'Li.H.VlLn CIRCUIT SOCKETS

40 pin .42 .40

DAi.-.l' male 2.33U w IS taiiste. 3.2aDA hood MP 1.00

NH L'.l- male 2.50

BB2SS female

2.002.001.30

1)11 I

I 2/P 1.3

DC37F maltDC 175 :,■;...,DC hood 2/1-DDSOF iiDJJSOS r.

DU.tO ho

CENTRONICS

4.20

ale

ii.60 H.00

RIBBON CAULK CONNECTORS17/34 B"dUk 1,93 4.15 3.0520/40 THS-H0 5,85 3.05 4.7023/30 H" disk 5.90 3.13 l.'.'O

VISA

c

Circle 55 on inquiry card.

Ail merchandise sold by California Digital is premium grade.Shipping: First five pounds $2.00; each additional add $.40Foreign orders 10% shipping. Excess will be refunded.California residents add 6% sales tax. COD's discouraged.Open accounts extended to state supported educational institu-tions and companies with a "Strong Dun & Bradstreet. "Warehouse: 15608 Inglewood Blvd. Visitors by appointment.

GREEN

PHOSPHOR MONITOR

The new Zenith ZVM-121 fea-tures a P31 green phosphor tubealong with 15 MHz bandwidth.Switch selectable Tor 40/80 char-acter screen. Fully compatablewith 80 column Apple cards.VDM-Z131 20 lbs.

$119

10 4-'109 1004-*99

. Shugart Associates

801/ R Disk Drive 15 lbs.

Shugarl 801/It with CP.BOfl power supply, nuplele In duul enclosure wiiti .ill ihi' m.-cessar-Documentation Included. 30 pounds. MSB-Same as ut>OVo but with two Shugftrt H01R 'lisSO pounds. .MSO-2H01Disk drive cable. 6 Feet SO conductor with edge ent both ends. WCA-830S ?25.00Bs>orl Disk drives. 220V. SOMHs add 550.00 pe:

SHUGART801R

S

I i mm i

dgft

NEW

from

Shugart

Technology

s

Megabyte

Hard Disk Drive

Packaged In the same physical size as the industry stan-dard 5 1/4" minifloppy disk drive. The micro-Winches-ter stores thirty times as much data (6.38 megabytesunformatted), accesses data twice as fast (170 milli-seconds) and transfers data twenty times faster (5.0megabits per second. )

The STIjOG is factory sealed to protect the media fromenvironmental contaminates. Requires only DC voltage.Dual California Digital 5 1/4" enclosure, t<t paaSTS06 drive and power supply. P JiVvU

Shugart Associates SA400 removablemedia disk drive for above package, add:

*300

Regulated

Power Supply

5 VOLT 5AMP

riila USED surplus power supp

$H95

TOtl FREE ORDER LINE

800)421-5041

TECHNICALS CALIFORNIA

213)679-9001

TWX 910325-6212

CaMFornIa Diq'iTAl

Post Office Box 3097 B • Torrance, California 90503

In a dark corner of a Control Datawarehouse our scouts have recently lo-cated a small quantity of brand new, vintage 1978, Control Data CL-41G matrix printers.

i CL-416 was designed for extra heavy duty industrial applications. Please do notconfuse this work horse printer with the new low cost imports.

The unit prints a full 9G character ASCII set at a conservative 175 characters / second.One kilobyte buffer accepts RS232 signals upto 9600 baud. Vertical forms control unitprovides added flexibility for business applications. The CL-416 has a split primarypower transformer to allow field voltages between 115 and 230 volts.Original cost of the printer is estimated at $5,000. California Digital blow out priceis only $1,395. Shipped via motor freight in factory sealed containers. SPC-CL.416

ONTROLDATA

L416 MATRIX PRINTER

1395

World's Beat Sailing Printer

EPSOMX 80

Immediate Delivery

$1150

HEWLETTPACKARD

HP85

Buperbrain64QSTfSSB64Q $:i:)f>0

Superbrain84D SYSSB84D zttbQ

KorthstarfifQ SY8N64Q 3295

Norihstar 64l> SYSNfMIJ 2805

NEC/PCB0OO SYSi'CaOOO mill

Apple II Plus SYSAP 1170

= == =V= Display= ^=_=T= Terminal

IBM Direct Price >129§California Digital

$1195

discountprice

Correspondence quality printing.

A lol of printers costing a lot more can't touch the MX-WFsperformance. It gives you a choice of 40. 80, 66 or 112 col-umns of punting in .is many as four distinct printing densitymodes, a total of twelve different combinations which cm |accommodate nearly anv printing requirement.

Bidirectional printing. Logical seekingof shortest lines. 80 CPS. &4 graphics characters Formshandling. The list of standard features goes on ami on. Thefact is thai there are few printers that can compete with theMX-80 -it ANV price. And none—ZERO - In its extraordi-narily affordable price range.iBCDEF BHI J1 LMWDPQRSTUVWX Y JABCDEF SI 11 <J

iliT.-.\"?

MArtflhMtl

ACCESSORIES FOR THE

COMPUTER

AMPEX

DIALOGUE 80CRT TERMINAL

$995

ft Anipex Corporation. The Dialogue 80 feature! removable keyboardwo pages (four optional) dual program keys, half intensity protecteds ana siaius line. Transmits data either black, line or character tr.ode.Excellent value. VDT-D80 shioniiiK 47 lbs.

VIDEO TERMINALS

ADDS Viewpoint

AiJDS Resent 25 numeric clusterADDS Regent 30 25th status lineADDS Regent 40 limited graphicsADDS Regent 60 Block modeAnipex Dialouge 80 two page.detatchDigital Equipment VT-100Digital Equipment VT-132Direct VP-800A emulatorHazeltine 1410Hazeltine 1420Hazeltine 1500Ilazeltine 1510Hazeltine 1520Hewlett Packard 2G21AHewlett Packard 2621PIBM 3101-10 character mode greenIB.M 3101-20 block modeLear Seigler 3A upper case onlyLear Seigler ADM5Lear Seigler ADM31Lear Seigler ADM42Visual 200

[Ylcvideo 910C (new)Televideo 912CTelevideo U20C

Televideo 5J50C detatchable keyed.Zenith Z-19

V1JT-VDT-VDT-VDT-VDT-VDT-VDT-VDT-VDT-VDT-VDT-VDT-VDT-VDT-VDT-VDT-VUT-VDT-VDT-VDT-VDT-VDT-VDT-VDT-

RVP

R25

R30

R40

R60

D80

VI00

VI32

P800

111410

111420

HI 500

H1510

HI 5 20

HP21A

HP21P

3101 1195

31012 1395

L3A 850

L5 945

595

850

950

1195

1495

995

1595

1895

call

750

795

L31L42V200TO 10

1385

1995

995

595

VDT-T012 665

VDT-T9i0 745

VDT-T950 085

VDT-Z-19 735

VIDEO MONITORS

13MC KG12C 18MHz

P-31 grn phosphorLeedex/Amdek 12"100Leedex 100 greenLeedex 100-B0Hitachi color 13"Zanith color 13"NEC green phosphorPanasonic color 10"Sanyo 9" BWSanyo 12" green phos.Sanyo 15" BWSanyo 13" color

$259129169197389379219

149235

259419

CALU-ORXIA CO.Mi'fl'ER SYSTEMSArithmetic Processor 7811 li/C 3319

Asynchronous ■erial interface 7710 129

Centronics Interface enrd 772H Ha

12K PaOM Module 7114 GS

Calender/Clock. Hal. back-up 7424 9i>

Parallel Interface 7720A S3

Programabte Timer 77-10A 99

Analog Digital converter 7-170A i)'.<

MICROSOFT PRODUCTS

Apple to Z-B0 CPU card 379

U.C. HAVES PRODUCTS

Microi.iiniem for Apple Slfl

COMPUTER STOP PRODUCTS

Double Vision / BO Column Video 289

INTERACTIVE STRUCTURES

1G Channel A/1) card AIO/S 275

MOUNTAIN COMPUTER PRODUCTS

Intro X-10 system for BSR 5236

intro X-10 card onlv 16!

16 channel AD/DA 8 oil 31i

Apple Clock battery back-up 22:

Supertalker SD200 24!

ROM Plus With filter lfi:

ROM Writer/Programmer 118APPLE BRAND PRODUCTS

Apple Language curd 45C

Floppy disk wtth controller 56C

Moppv disk without controller 49;

Apple-parallel interface 17:SSM MICROCOMPUTERDual serial par:illel Interface AIOSORRENTO VAELKV ASSOCIATE

•alia

(Pascal)

S-100 BOARDS

Assembled • Tested • Burned-in

Calif. Computer

810A

('-no

DMA. iXOtt

HDC

Codboui E-80 34 Ml, l.MII/

lillC

ti/HO

a«j«ii>oui soaa/aoafi dui

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HDC

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Measurement Svs

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cl.oclt. 8 vector BDC

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'(II) /.

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I1DC

SBC3

r,i..--L-i. 1 nc-i

Ingle board

cpu '■ noppv

itn.lle

plus I/O

HDC

M)C1

MAIM 'HAMES

Calif. Computer

200 A

12 slot

i;x.\i

-C220D

TBI 12 slot tabk

KX.M

-112

TEI ?2 slot tabl.

IJNM

- ru

Godhotn mainfrn

1-XM

-OMI

MEMORY BOAR1

C ilil. !.:.■■■ |.Ut.-!'

083A

61k

v HD.\:

-C'Oti'.

cut. Computer

II!'. 1

JK

BUM

-C201S

Cilif. Computer

II (J .:

2k

Bin

-C2(i:i2

! BOARDS

Researeti 32K. 27tuBUM-UPS!

111-100proeran.nier UliM-PUH)

mlile dwnsttji,HD1-Ml

s'i Systeixa Versafloppy 11double ctensiiy Mul -\l :•

Tarhell D/D BUF-TF2

Morron UesifiH Di.:l. Jockey 1sinsle density HUI--1U!

Morrow Deaicn Disk Jockev IIdouble density BU1--UJ2

L\TKH1 ACE BOARDSCalif. CoiKputer 271H I/O

■1 serlal/2 par I BUT-C2T18Morrow Designs Sniichboard

2 serial/4 pari HDT-MSHMorrow Designs Multitioard

i swtal/3P. ■•• BUT-11MHOodboul tnterfac.^r One

2 bcvUiI/2 par 1 BOS-tifil1 .u Bjoui btterfueer run

1 BerUt/3 par I HDS-CIi:1

Sl'i.CIALIl V BOAaiJSgl' Ctw puter real n" u

Rotron Muffin Fan

*1477

1 .Ulltl

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Spuctru.

use

1). c.

II

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UDS-11M1

Mullet. Products

extender board

K

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kit

BUS

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J12.00 <? 10010.50 6' 1000

'•■

VfSA

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All merchandise sold by California Digital is premium grade.Shipping: First five pounds $2.00: each additional add $.40Foreign orders 10% shipping. Excess will be refunded.California residents add 6% sales tax. COD's discouraged.Open accounts extended to state supported educational institu-tions and companies with a "Strong Dun & Bradstreet. "Warehouse: 15608 Inglewood Blvd. Visitors by appointment.

nimlg fifi nn Innuirv parri I

115 VAC. 7 Watts WB2A1Factory fresh Muffin fansNOT pull-outs. KHF-4M

TOLL FREE ORDER LINE

800)421-5041

TECHNICAL & CALIFORNIA

213)679-9001

TWX 910 325-6212

PLASTIC LIBRARY CASE SUPPLIED WITHPURCHASE OF EVERY TEN DISKETTES

lis.RL.

In

TTTTn

Quantity One Hundred

INVENTORY REDUCTION SALE!

California Digital has recently purchased over 200,000 Memorex Diskettes. Frankly we have over committedand must liquidate our excess inventory. This is your chance to take advantage of this special buying opportunity.All diskettes sold by California Digital include a free library case ($5.00 value.) Offer expires November 30,1981.Shipping: 51/»" Mini-Diskette add $6.00 per hundred. Eight inch add $12.00 per hundred. Calif, residents add 6%

Partdumber

Description

Quantity

List Price

PrepaidOne Hundred

Credit CardNet 30

Less ThanOne Hundred

Extension

3401

Five Inch for Apple,TRS80, PET, Atari

>4.50

1.99

2.15

2.49

3403

Five Inch Ten Sector forHorizon, Zenith/Heath

4.50

1.99

2.15

2.49

3405

Five Inch Sixteen SectorVector Graphics

4.50

1.99

2.15

2.49

3431

Five Inch Soft Sector withReinforced Hub Ring

4.65

2.19

2.35

2.69

3060

Eight Inch Single SideDiablo, IBM 3740

5.00

2.19

2.35

2.69

3090

Eight Inch Double DensityRadio Shack Model II

6.50

2.95

3.19

3.49

3114

Eight Inch Double SideDouble Density

7.00

3.49

3.75

4.95

Individual

Address

City

\ Card No.

Company

Phone

State

Zip

Exp.

Computer

Sub TotalTax

ShippingTotal

California DiqiTAl

Order Toll Free!

w~ * . . v » r, . « »-. M . . « ,. (800) 421.5041

4738-156thStreet • Lawndale, Calif. 90260 (213)679-9001

1858 EVERGREEN • DUARTE, CALIFORNIA 91010 • TELEPHONE (213) 357-50(

JUST WRAP KIT

Just Wrap tool fordaisy chain wiring.Tool strips as itwraps and cuts.Includes one 50 footspool of wire.

Part No.

Description

Price

JW-1'

Just Wrap Tool

$14.95

JWK-6

Tool w/4 Spools and

JUW1

24.95

R-JW*

50 Ft. Replacement

Wire

3.49

JUW-1

Unwrapping Tool

3.49

•Specify Color: Red, Blue, White orYellow.

Regular Modified

Wrap Wrap

HAND WRAP TOOL

Description Price

Regular $6.95

Modified 7.95

TERMINALS

• .025

HWt.l

" mill NIHIL tip]

(0,63mm)Square Post

mrr-i

• 3 LevelWire-

MM

Wrapping

■wn

• Gold Plated25 PER PKG.

Part No. Description

Price

WWT-1 Slotted Terminal

$4.98

WWT-2 Single Sided

Terminal

2.98

WWT-3 IC Socket Term.

4.98

WWT-4 Double Sided

Terminal

1.98

INS 1 Insertion Tool for

above

2.49

SOCKET WRAP - ID

•••••••••••• Slipped onto

»K1»K17HI»»fl22»» sooPkPet before

Ur«|>-ID

12 II 10 1 8 7 6 5 « 3 2 1

wrapping toidentify pins.

Bulk Bulk

Part # Price Price Part # Price Price

14ID 1.49/10 5.50/100 22ID 1.49/5 5.95/50

16ID 1.49/10 5.95/100 24ID 1.49/5 5.95/50

18ID 1.49/10 5.00/50 28ID 1.49/5 6.50/50

20ID 1.49/5 5.00/50 40ID 1.49/5 5.00/25

PRODUCTS

IP.C.B.

TERMINAL

STRIPS

The TS strips providepositive screw activatedclamping action, accom-modate wire sizes 14-30 AWG (1,8-0,25mm). Pins are solder plated copper,.042 inch (1mm) diameter, on .200 inch(5mm) centers.Part No. Description Price

TS- 4 4-Pole $1.69

TS- 8 8-Pole 2.59

TS-12 12-Pole 3.49

TS6MD 2-Pole Interlocking 3/1.79

DESOLDERINGPUMP

Easy one hand*• operation.

Rugged all metalconstruction.ReplaceableTEFLON® Tip. Selfcleaning on each stroke.Suction precisely regulated for reliabledesoldering without damage to delicatecircuitry.

DSPI Desoldering Pump $9.95

LOGIC PROBE

>

Compatible with all logic families us-ing a 4 to 15V power supply.Thresholds automatically programm-ed. Visual indication of logic levels toshow high, low, bad level or open cir-cuit logic pulses.

• 10 N sec. pulse responses

• 120 K input impedence.

• Automatic resetting memory.

• Includes tip with protective cap &coiled cord.

PRB-1 $36.95

LOGIC PULSER

Superimposes a pulse train (20 pps) ora single pulse onto the circuit nodeunder test without un-soldering IC's.

• Automatic polarity sensing

• 2 us pulse width

• Finger tip push button actuated

• Includes tip with protective cap &coiled cord.

PSL-1 $48.95

VACUUM VISE

Unique vacuum-basedlight duty vise forprecision handling ofsmall components andassemblies. RuggedABS construction. XW (32mntravel for maximum versatility. Alsofeatures screw lugs for permanentinstallation.

VV1

Vacuum Vice

$3.49

jgjfc.

.■jfA Kg- HOBBY-

^/Al ^t WRAP

<dfl BlTOOL

-TTF*^^^63

• Auto-Indexing ^^h^ WW

• Anti-Overwrap ^^

• Modified Wrap

Part No. Description Price

BW2630 Tool $19.85

BT30 #30 Bit (not incl.) 3.95

BT2628 #28 Bit (not incl.) 7.95

BC1 Batteries & Charger 14.95

INSERTION/EXTRACTION

TOOLS

Part No.

Description

Price

INS1416

14-16 pin Inserter

$3.49

MOS1416 14-16 pin MOS Safe

Inserter

7.95

MOS2428 24-28 pin MO:

Inserter

7.95

MOS40

40 pin MOS Safe

Inserter

7.95

EX1

14-16 pin

IC Extractor

1.49

EX2

24-40 pin

IC Extractor

7.95

» WK-7 IC

full ■

JN- —INSERTION K.

II

Uj

1 L4: I—. Complete IC In-

1

serter/ Extractor K

/

H I

Individual Com-

]i

jM

L ft, Ik ponents (listedY H H above) $22.95

IC DISPENSER

Allows IC's to be dis-pensed from their tube 1at a time and picked upby insertion tools above.

• Dispenses 8-42 pin

IC's • Compatable with

all IC carrying tubes •

Use with WK7 for MOS «

safe insertion. •Part No. DescriptionMDD1 1 Chan. Dispenser $21.85

MDD5 5 Chan. Dispenser 83.43

MDD10 10 Chan. Dispenser 160.45*No Discount.

Price

OLL FREE ORDERING NUMBER 1(800) 423-7144

RIGHT ANGLE HEADERS

SOLDER TAIL WIRE WRAP

IDC CONNECTORS

Size Part No.

Price

Part No.

Price

10 IDH10SRB

$1.20

IDH10WRB

$2.60

20 IDH20SRB

1.90

IDH20WRB

4.15

26 IOH26SRB

2.75

IDH26WRB

5.35

34 IDH34SRB

3.75

IDH34WRB

6.25

40 IDH40SRB

3.75

IDH40WRB

7.35

50 IDH50SRB

4.75

IDH50WRB

9.20

.1*' Spacing. Mounts on

PC Board & Mates

with IDS Socket below.

Ejector Bars -

4/1.00.

DB25P

$2.95

DB25S

3.95

DB25C

1.50

25 PIN "D" CONNECTORS

Solder Style Part No. Price

Male

Female

Cover

IDC Style

Male IDB25P 6.25

Female IDB25S 6.60

Cover IDB25C 1.60

Solder Style solders onto cable, IDCStyle crimps onto cable with vise. 9,15, 37 and 50 pin available also.

WIRE WRAP WIRE

#30 Wire Wrap Wire

Length

100/Bag

500/Bag

1K/Bag

2.5"

$1.38

$3.94

$6.81

3.0"

1.43

4.25

7.46

3.5"

1.51

4.57

8.11

4.0"

1.56

4.88

8.73

4.5"

1.63

5.21

9.39

5.0"

1.69

5.54

10.04

5.5"

1.74

5.92

10.69

6.0"

1.82

6.23

11.34

6.5"

2.11

7.08

12.99

7.0"

2.19

7.44

13.68

7.5"

2.29

7.78

14.40

8.0"

2.35

8.12

15.10

8.5"

2.40

8.46

15.80

9.0"

2.46

8.92

16.51

9.5"

2.53

9.15

17.22

10.0"

2.63

9.58

17.91

EDGE CARD CONNECTORS

Size Part No. Price

10 IDE10B

$3.95

20 IDE20B

4.35

26 IDE26B

5.00

34 IDE34B

6.05

40 IDE40B

6.90

50 IDE50B

7.50

.1" Spacing. Crimps onto

cable

with

ordinary vise & mates wi

h standard

.062" Card Edge.

&/*

CABLE PLUGS

Size

14162440

Part No.

IDP14BIDP16BIDP24BIDP40B

Price

$1.451.652.504.15

.1" Spacing. Crimps onto cable withordinary vise & plugs into standard ICSocket.

WIRE WRAP SUPPLIES

All lengths are overall, including 1" stripon each end. Choose from colors; Bed,Blue, Black, Yellow, White, Green,Orange, and Violet.

ORDERING INFORMATION

Prepaid orders over $50 shipped prepaid via

UPS. All others add $3.00 for handling. VISA,MC, COD's and open account orders will becharged freight. $15 minimum order. $100minimum open account order.

■ ".7-.,

*

Size Part No.

08 ICN083WBSG

Each.44

Tube

52x .39 = $20.28

14 ICN143WBSG

.53

30x .46 = $13.80

16 ICN163WBSG

.58

26x .50 = $13.00

18 ICN183WBSG

.78

23x .68 = $15.64

20 ICN203WBSG

1.00

21 x .85 = $17.85

22 ICN224WBSG

1.07

19x .92 = $17.43

24 ICN246WBSG

1.09

17x1.09 = $15.98

28 ICN286WBSG

1.43

15x1.23 = $18.45

40 ICM406WBSG 1.85Selective Plating provides g

10x1.60 = $16.00

Did in contact

where it counts. 3-level wrap

. Save by buy-

ing sockets by the tu

be. All

gold available at

Vjtt/pin extra charge.

* * * No Discount

Order

$15 - 99

100- 199

200 - 499

500 - 999

1000 up

_

\

^

Solid Color

Color Coded ^^jjl

Size

10 ft.

100 ft.

10 ft.

100 ft. ^H

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

SOCKETS

Size Part No.

Price

10 IDS10B

$1.88

20 IDS20B

2.75

26 IDS26B

3.50

34 IDS34B

4.50

40 IDS40B

5.40

50 IDS50B

6.50

.1" Spacing. Crimps onto cable with

ordinary vise & mounts to header

sold

above.

WIRE KITS

Kit No. 1

- $9.95

250

3"

100

4%"

200

3V2"

100

5"

100

4"

100

6"

Kit No. 2

- $24.95

250

2V2"

250

5"

500

3"

100

bW

500

3Va"

100

6"

500

4"

100

6V2"

250

4%"

100

7"

Kit No. 3

- $34.95

250

2V4"

500

4V4"

500

3"

500

5"

500

3V4"

500

5Vz"

500

4"

500

6"

Kit No. 4

- $59.95

500

21/2"

1000

41/2"

1000

3"

1000

5"

1000

31/2"

1000

5V4"

1000

4"

1000

6"

DISCOUNT SCHEDULEAmount

Netless 10%

less 15%less 20%less 25%

Discount and the name ofthis magazine must be men-tioned at time of order to getdiscount. Discount applieson all items except as noted,"No Discount."

Circle 291 on inquiry card.

7400

SN7400NSN740WSN7402NSN7403NSN7404NSN7405NSN7406NSN7407NSN7408NSN7409NSN7410NSN7411NSN7412NSN7413NSN7414NSN7416NSN7417NSN7420NSN7421NSN7422NSN7423NSN7425NSN7426NSN7427NSN7429NSN7430NSN7432NSN7437NSN7438NSN7439NSN7440NSN7441NSN7442NSN7443NSN7444NSN7445NSN7446NSN7447NSN7448NSN7450NSN7451NSN7453NSN7454NSN7459NSN7460NSN7470NSN7472NSN7473NSN7474NSN7475NSN7476NSN7479NSN7480NSN7482NSN7483NSN7485NSN7486NSN7489NSN7490NSN7491NSN7492NSN7493NSN7494NSN7495NSN7496NSN7497NSN741O0NSN74107NSN74109NSN74116NSN74121NSN74122N

.19 SN74123N

.22 SN74125N

.22 SN74126N

.22 SN74128M

.22 SN74132N

.23 SN74136N

.23 SN74139N

.23 SN74141N

.26 SN74142N

.23 SN74143N

.22 SN74144N

.29 SN74145N

.29 SN74147N

.39 SN74148N

.59 SN74150N

.29 SN74151N

.29 SN74152N

22 SN74153N

.35 SN74154N

.29 SN74155N

.29 SN74156N

.29 SN74157N

.29 SN7415BN

.25 SN74160N

.45 SN74161N

.23 SN74162N

.29 SN74163N

.25 SN74164N

.29 SN74165N

.29 SN74166N

.19 SN74167N

.79 SN74170N

.57 SN74172N

.95 SN74173N

.95 SN74174N

.79 SN74175N

.79 SN74176N

.85 SN74177N

.79 SN74179N

.19 SN74180N

.19 SN74181N

.19 SN74182N

.19 SN74184N

.25 SN74185N

.23 SN74186N

.29 SN74188N

.29 SN74190N

.34 SN74191N

.34 SN74192N

.38 SN74193N

.34 SN74194N

1.60 SN74195N

.49 SN74196N

.95 SN74197N

.55 SN74198N

.65 SN74199N

.35 SN74221N

i.75 SN74251N

.39 SN74273N

.57 SN74279N

.45 SN 74283 N

.45 SN74284N

.69 SN74285N

.65 SN74290N

.69 SN74298N

!.90 SN 74365 N

.20 SN74366N

.32 SN74367N

.37 SN74368N

.95 SN74390N

.29 SN74393N

.39 SN74490N

CMOS

CD4000

CD4001

CD4002

CD4006

CO4007

CD4008

CD40O9

CD4010

CD4011

CD4012

CD4013

CD4014

CD4015

C04016

CD4017

CD4018

CD4019

CD4020

CD4021

CD4022

CD4023

CD4024

CO4025

CD4027

CD4028

CD4029

CD4030

CD4031

CD4032

CD4034

CD4035

C04037

CD4040

CD4041

CD4042

CD4043

CD4044

CD4046

CO4047

CD4048

CD4049

CD4050

CD4051

CD4052

CD4053

CD4055

CD4056

CD4059

CD4060

CD4066

CD4069

CD4070

CD4071

CD4072

CD4073

CD4075

CD4076

CD4077

CD4078

CD4081

CD4082

CD4085

CD4089

CD4093

CD4094

3.252.153.25.95

3.952.959.251.39

1.29.35.35

1.952.95

2.95

CO4098

CD4099

MC14408

MC14409

MC14410

WC14412

MC14415

MC14419

CD4501

CD4502

CD4503

CD4505

C04506

CD4507

CD450B

CD4510

CD4511

CD4512

CD4515

CD4516

CD4518

CD4520

CD4555

CD4556

CD4568

74C0074C0274C04

74 COS

74C10

74C14

74C20

74C30

74C32

74C42

74C48

74C73

74C74

74C85

74C89

74C90

74C93

74C95

74C107

74C151

74C154

74C157

74C160

74C161

74C163

74C164

74C173

74C174

74C175

74C192

74C193

74C195

74C240

74C244

74C373

74C374

74C922

74C923

MM80C95

MW80C97

2.292.2512.9512.9512.9512.958.954.95.39

3.751.191.191.39

2.751.451.391.254.95

.991.351.89

5.951.191.191.49

1.192.493.502.101.651.55

1.552.192.192.392.395.395.651.501 25

74LS00

74LSOON

74LS01N74LS02N

74LS03N .28

74LS04N .35

74LS05N .28

74LS08N .28

74LS09N .35

74LS10N .28

74LS11N .39

74LS12N .33

74LS13N .47

74LS14N .95

74LS15N .33

74LS20N .26

74LS21N .33

74LS22N .33

74LS26N .33

74LS27N .33

74LS28N .33

74LS30N .26

74LS32N .33

74LS33N .55

74LS37N ,45

74LS38N .39

74LS40N .26

74LS42N .79

74LS47N .79

74LS48N .95

74LS51N .26

74LS54N .29

74LS55N ' .29

74LS73N .45

74LS74N .42

74LS75N .59

74LS76N .45

74LS78N .45

74LS83AN .79

74LS85N 1.19

74LS86N .45

74LS90N .57

74LS92N .75

74LS93N .75

74LS95N .88

74LS96N .98

74LS107N .45

74LS109N .45

74LS112N .43

74LS113N .43

74LS114N .43

74LS122N .55

74LS123N 1.19

74LS124N 1.35

74LS125N ,89

74LS126N .52

74LS132N .79

74LS136N .49

74LS138N .85

74LS139N .85

74LS145N 1.25

74LS148N 1.49

74LS151N .79

74LS153N .79

74LS154N 1.70

74LS155N 1.19

74LS156N ,99

74LS157N .85

74LS158N .75

74LS160N 1.05

74LS161N 1.15

74LS162N 1.05

74LS163N 1,05

74LS164N74LS165N

74LS166N

74LS168N

74LS169N

74LS170N

74LS173N

74LS174N

74LS175N

74LS181N

74LS190N

74LS191N

74LS192N

74LS193N

74LS194N

74LS195N

74LS196N

74LS197N

74LS221N

74LS240N

74LS241N

74LS242N

74LS243N

74LS244N

74LS245N

74LS247N

74LS248N

74LS249N

74LS251N

74LS253N

74LS257N

74LS258N

74LS259N

74LS260N

74LS261N

74LS266N

74LS273N

74LS275N

74LS279N

74LS283N

74LS290N

74LS293N

74LS295N

74LS298N

74LS324N

74LS347N

74LS348N

74LS352N

74LS353N

74LS363N

74LS365N

74LS366N

74LS367N

74LS368N

74LS373N

74LS374N

74LS375N

74LS377N

74LS385N

74LS386N

74LS390N

74LS393N

74LS395N

74LS399N

74LS424N

74LS668N

74LS670N

81LS95N

81LS96N

81LS97N

81LS98N

1.151.99

2.201.151.15

1.492.201.101.101.191.40

1.754.40

1.101.191.75

1.951.951.19

.691.951.95

.651.951.951.702.352.951,752.291.691.691.691.69

LINEAR

78H05

78M06

78M.G.

LM105H

LM108AH

LM300H

LM301CWH

LM304H

LM305H

LM306H

LM307CN/H

LM308CWH

LM309K

LM310CN

LM311DJCN/H

LM312H 1.75

LM317T 1.70

LM318CN/H 1.49

LM319N/H 1.25

LM320K-XX-

LM320T-XX*

LM320H-XX* 1.25

LM323K 4.95

LM324N .95

LM337K 5.95

LM338K 6.95

LM339N .95

LM340K-XX' 1.75

LM340T-XX* 1.25

LM340H-XX' 1.25

.992.95

3.25

1.25

1.35

LM344H

LM348N

LM350K

LM358CN

LM360N

LM372N

LM376N

LM377N

LM380CMN

LM381N

LM383T

LM386N

LM387N

LM390N

NE531V/T

NE555V

NE556N

NE561T

NE565N/H

NE566H/V

NE567V/H

NE.S92N

LM702H

LM709N/H

LM710N/H

LM711N/H

LM715N

LM723N/H

LM733N'H

LM739N

LM741CN/H

LM741CN-14

LM747N/H

LM748N/H

LM760CN

LM1310N

MC1330

MC1350

1.951.205.60

1.953.752.75

1.401.953.75

1.751.502.75

1.95.65

MC135S 1.75

LM1414N 1.90

LM1458CN/N .49

MC1488N .99

MC1489N .99

LM1496N

LM1556N

LM1820N

LM1850N

LM1889N

LM2111N

LM2900N

LM2901N

LM2917N

CA3013T

CA3018T

CA3021T

CA3023T

CA3035T

CA3039T

CA3046N

LM3053N

CA3059N

CA3060N

CA3062N

LM3065N

CA3080T

CA3081N

CA3082N

CA3083N

CA3086N

CA3089N

CA3096N

CA3097N

CA3130T

CA3140T

CA3146N

CA3160T

CA3190N

CA3410N

MC3423N

MC3460N

SG3524N

CA3600N

LM3900N

LM3905N

LM3909N

LM3914N

LM3915N

LM3916N

RC4131N

RC4136N

RC4151N

RC4194TK

RC4195TK

ULN2001

ULN20O3

SN75450N

SN75451N

SN75452N

SN75453N

SN75454N

SN75491N

SN75492N

SN75493N

SN75494N

TL494CN

TL496CP

1.50,95.953.101.75.992.502.952.191.993.492.992.751.291.291.493.193.194.95

1.691.55.802.993.491-991.301.192.491.191.95

3.953.953.39

.591.19

.983.75

3.70

.49

.89

1.65

RETAIL STORES OPEN MON-SAT

STORE »1: 1310-B"E.Edinger, "

STORE "2: 542 Trimble Road. San Jose, CA 95131 • (408) 946-7010

"Retail prices may vary.

AEMVNCED

COMPUTERPRODUCTS

HP-85S2695.00

HP 7225 Graphics Plotter 179500

HP 16K Memory Module 265 00

HP 5 1/4" Dual Waster Flex Disk Drive. 2100 00HP 5 1/4" Single Master Flex Disc Dnve1295 00

HP Personality Module 700.00

HP ROM Drawer 40.00

HP Plotler/Prinler ROM 130 00

HP Input/Output ROM 260 00

HP Matrix ROM 130.00

HP Serial Interlace (RS-232C) 350.I

HP-83 $1895.HP-41: Powerlul, Yel Easy lo Use

• The HP-4t communicates withHP 41-CV you in words as well as numbersYou can customize the HP-41 myour awn designProgramming is last and easyContinuous Memory saveseverything

Optional Peripherals allow youlo expand capabilitiesHP-41 SysteiHP-41 Systei

[tipple computer

" Sales and Service

Apple II® 64K

: ?68K°RSa°S Maxi-System

• Disk II w/controller

• Apple II w/48K Call for more pricing!

Total Value $271900 your price $222900sa^e(- For Pascal System add $42500

dtcippta E hardware clearance up to 25% off

. 398.00. 675.00. 178 00. 105 00. 315.00196.00 HP-Quad RAM 85 00

HP-41CV HP-Card Reader ,.275.00 HP-Optical Wand .HP-41C HP-Plotier/Prii

v MINIMOVER-5

j®crgV>1 ROBOTIC ARM

Completely ^tt^^^k

«.„., M m

nation or ^mt

Assemb y^^H ^B ^P

tic Pricinles A

• Automation orRobollc Assembly .

• Education inRobotic Prlclple!

• Artificial Inlellgence Experiments

• Computer Art and Games

$1695

00

Armbasic Sotlware lor TRS-80 eicm,

^Applications Manual *"9

AppllcallonsJRefurence Manual $16"

California Computer Systems 2200

SUPER S-100 BUY!

VISTA COMPUTE"

Dalasavei'-UniriofiuplaOiePS 395.00 New

Vocalyier'-Voico CartJ 225.00 Ne*

Vi5ion80"'80i24CarrJ ... 325 00 New

VisionJ0'-40col BfiriancemeM 175.00 New

AflOOOjaaPeniStyB-Controller E95 00 New

Microsoft Z-80 Softened .. . !5900

MicrosolMSKRarrcaro IB9.00

SSMAIOSeiial/ParallonO . .165.00

CCSABynchfonou>7710ASeiial .. . .139.00

Apple Joyillcfc'GESU" 54.35

Mountain Computor

Romplus - 169.00

Rom Writer 159.00

lntraWX-10 ... 180 00

lniiof/X.10 Remote Cont Syj 249 00

SuperTalkor ... 27500

MusrcSyitan- 49900

CPS Multifunction 229.00 New

Expansion Chassis 699 00 New

□CHayesMlcfomoflemII .,., , .29900' New

DC Hayes Smarl MorJom 349,95 New

Tliund ere lock . . 125.00 New

X-10 HO Option" .... 49.00 New

Pascal For Anove" .;9oo New

CCSPar allot Ca'07!Apple Compute'Apple H i-SpecO Seri

fcipplG//

Buy a

System

and

Save

• 12 Slot Mainframe

• 64 bynamic HAM

• CP/M™ 2.2

• Z-80 CPU 4 MHz w/Serial 10

• Double Density Disk Controller

• Interface to Vista V-1000 Chassis

SPECIAL PACKAGE PRICE -poo OQFOR COMPLETE SYSTEM 'Oy9-with (2) Shugart Double DensityFloppys mounted. add 1495.00

Proto Clips

Lii-PiriCLiO PC-16

:'.i-t',., ciip PC-a^..or,., ci.p PC-io

Proto Boards

21.00 PB-203A25 00 PB-203A-h43 00

54 0097 00149.00129 00

Novation:

AUTO-CAT™

Automatic AnswerDirect Connect0-300 Band

List 27995

ACP24595

OAT™ Lis' 198°"

Answer Originate ACP16900

D-CAT

direct Connect 1

0-300 Band.

List 249"'

acp18900

New #PPta software

Visicalc —Now Better Than Ever 169.00Visiplol—Graph your

Visicalc Worksheels 149.00Visitrend/Visiplot — Visiplot

w/Trend Analysis 239.00Visidex—The Ultimate

DBMS Visicalc Compatible 219.00Visiterm—Communicale

w/other Systems 209.00

BPI General Ledger 299.00

BPI Accounts Receivable 299.00

BPI Inventory 299.00

Stockfile Inventory System 349.00

Infotory Inventory System 289.00

Microcom Microcourier 229.00

Microcom Microtelegraph 229.00Accounting Plus II Biz Pkg. 1250.00

Stoneware DB Waster 189.00Stoneware Utility Pkg (For above) 89.00

We only offer AppleCPM software whichhas been evaluatedby our software staff.

WORDSTAR-The Benchmark ofWordprocessing software requires Z-80& 80x24 349.00

VTS-80 CP/M-Wordprocessor has noscreen menus uses new keycaps(supplied) to display Key functions

319.00 NewMAIL-MERGE-A Wordstar Enhance'ment Pkg. allows lorm-letter genera-tion & chained printing 169.00SPELLGUARD-Will proofread Wordstar& VTS-80 Text hies against anexpandable 20.000 word dictionary

169.00SUPER SORT-Wtll sort, merge. &perform record selection on yourCP/M Data Files 169.00

FORTRA 80-By Microsoft 195.00

COBOL 80 Bv Microsofl 749.00

ACS BASIC ACCOUNTING SYSTEM, Totalaccounting system includes G'L, A/R. A/P.PAYROLL 699.00 New

Breakthru in Apple IT Mass Storage!

Vista A800 Quad^Density DMA 8'Controller

Disk

^

Model A800. . .. only$59500

[Special Complete Subsystem Offer |

• V1000 w/two Qume Datatrack 8 • Cable, ready to run

• A800 Apple II 8" Disk Controller

Total Value $293900 your price$249500

Rockwell Sin9'e BoardComputers

AIM 65W/1KA!M65w/4KSK BASIC ROMl 4K ASSEMBLERv POWER SUPPLYENCLOSURE'TOTAL SYSTEM w/4KSYNERTEKSYM-1SO Z-80 STARTER KITSO 2-80 STARTER KIT ASTSD SBC 100 Z-80 A&TSD SBC 200 Z-80 A&TRCACOSMACVIPCROMEMCOZ-80SBC

9.00ROM 84.0064.9549.95669.00239.00367 00450.00367.00399.00199.0044900

A ATARI800 & 400

Personal Computer SystemATARI 800 $79900ATARI 400 $37500

ATARI 800 Includes: Computer Console, BASIC Lang. Cartridge. BASICLanguage Programming Manual. 800 Operator's Manual w/Notebook,16K RAM Module, Power Supply. TV Switch Box.

BK RAM16K RAM

BM Interim.!-Program fieco'Qf rStlfiin- »0M nmiditiEflucat-xSySSrti Mailer Cal"SgeMX BASIC

499 00 hw* Finance

295 DO ihtitki smm Ciiuii 'Tin-i

795 00 uS H.5IMV

«» US GowrniT-OT

919S SuMrvisorv SuW

189.95 fluid History drtesie-'ni

MBO Bast SccuMigy

Cou^si

nt AKOjit"*)

t/ea! CijsspCS iEiqi>jniBuiness Crjinnvjr«cai<insBast Csycnoio],

Etteclive ww.nt]

31OC35003500

35 OC35 0035003500350035 00350035 0035003500

Bjs-; E*tOOH

flaw Armenia

IlUC Ciri i-l ''>cir Cut

BASIC «J'T r'aqumi

". V.U 'Jprnv, Woflii"IftK HMf We",,!-, Va]ul'

Outinii

P.O. Box 17329 Irvine, Calif. 92713

Direct Order Lines: (714) 558-881 3

(800) 854-8230 or (800) 854-8241

Circle 8 on inquiry card.

DRIVER'S LICENSE « OR MAJOR CREDIT CARDft IS REQUIREDON ALLCHECKS MONEY ORDEROR CASHIER CHECK WILL FACILITATE THESHIPMENT OF YOUR PURCHASE.

^yUDSANeED^-

Y TT=^COMPUTER

^'AlreODUCTS

FIRST TO OFFER PRIME PRODUCTS TO THE HOBBYIST AT FAIR PRICES!1 ■ PrOVeil Quality Factory tested products only /^SaT^\

2. Guaranteed Satisfaction ( 4i&f

Call For Special School Discounts x*9.95

"V-DRIVE"

THE LAST WORD IN 8"FLOPPY-DISK ENCLOSURES

THi VISTA V-1000 FLOPPY DISK DRIVE SUBSYSTEM

• D*uMC^aasiwmrtBrid9rtB»^icr«ssla*T«|X)SKi™nBartlmajitrio«Bui»lB mdndy wd Hectncaly aawnatate srtfc sided dmes— rcluJnj Hie nasi pr«ularB- red WreftsW and Sryjart Itocpy dr» Mn aril 8- rch streaming we unts • S foragecapacity lrwn0ilD40nMoaeyW • ■n&sliar ajaiTy cabnei wm*«a (rail be»l •Me* alUL art OS r(A standards* MHOMl Savfigs! Fran and mat mma rai monts

provttd .(' ■■ em cftarge ino ntamaf skta! • Desk of rat* mourtabre • Fmuk

mdUB towirwn ««tt nmowat* sir assemrjfy that atom easy cab net wsrl lormgand

n-.winj m Drrves pul out lot easy wvw art martenance.

DISCOUNT PRICES

CABIHFT S 395

CABINET aM Bl sngte sow crrves (tadufrg pcwar 5up>y & caUel S1495CABINET «H.(2> do»e sasd onves [retmg pom 3joti & cat*-]. S1995

for TRS80? MODEL I,PMC 80. ZENITH H89,S-100, etc.ONLY31000ea.MODEL V-801,80 TRACKS, SSONLY42500ea.

2 DRIVE CABLE. . 29.95 4 DRIVE CABLE.. 39.95

^

MOSTEK MK40154K Dynamic RAM

Refresh while supply lasts only .49°Pin equivalent to MK4027 except has 1 ms.

S-100 WW

$2.99 each

FIRST QUALITY AT SURPLUS PRICE

2708 EPROMS

PRIME-450 Ns.8 for $29.95

4K STATIC RAM SELL-OFF

Zilog 6104-4

Same as TMS 4044 but designed specificallyfor Z-80 based systems. This is full-spec4Kx1 RAM. 450 Ns.

While supply lasts $1.49 each.

TTTTTTTTT

SPECIAL PURCHASE$59.95 Limited Supply $59.95

16K Affair RAM Boards. Fully Populated as is.

FLOPPY DISK DRIVES

• Double Density

ACP LOW PRICE $569.95

TandomTMlOO-l SV." Duk Drive 249.95

MPI B51-5V.". 40 iracka 239.95

Shugan SA400-5V<" 35 tracka 295.00

Shugarl 800/801 R 8" 449.00

Sl«mnn« Shugan Compallble Model FDD-120-BD 429.00

PERSCI Model 377 Dual 1195.00

MPI B52 5V Dual 348.00

WANGO/SIEMENS 82 290.00

MPI 91 Double Track Denalty Single Side, 60 Tracks 375.00

MPI 92 Double. Trick Penalty Double Side, 160 Track.... 475.00

6800 MICROMODULE™ PRICE LIST

MODELNO DESCRIPTION PRICE

960OA

9609

9601

9602

9603

9604

9605

9610

6 Slot MotherCard Cage8 Slot Mother BoardPower SupplyDC Input Power SupplyUtility Proto Board1611 Arilh. P'OC/Memory Module

9612 Buffered Uhlily Proto Board

9616 32K EPROM/RAM Module

9617 EPROM Programming Head96.20, 16, Channel Parallel I/O Module9622 Serial-Parallel I/O Module9627 16K Sialic RAM Module 470ns

9629 32K Slanc RAM 450ns9629A 32K Sialic RAM 200ns

9630 Card Extender

9640 Multiple Programmable Timer

9650 8 Channel Duplex Serial I/O Mod.

9655 Intelligent Tape Controller

96103 32/32 I/O Module

96702 Contact Closure Module

UNPOPULATED BOARDS 'Also Available)

$24.95 TRS-80/APPLE S24.95

MEMORY EXPANSION KITS.41 16's. 16K 1200/250 ns.j

8 pes for S24.95 nnnn

Specify Computet If IA IUI

Call For Volume Pricing ■■"■■■

16K

CENTRONICS PRINTER

Model 737

• CenUonics complete printer

• The 737 has everything Checkand compare the features.

• New low pnee $835.00

32K STATIC RAM BOARD

2 or 4 MHz Expandable uses 2114L'sS-100

16K4 MHz Kit . .159.9516K4 MHzA&T ,217.9532K MHz Kit . 289.9532K4MHzA&T 339.00

Bare Board 39.95

Bare Bd. w/all partsless mem 99.95

NEW! from Zilog

Z-8 CPU comes withTiny Basie & debugprogram on the I.C.

BIPOLAR CPU SALE

Signetics 8x300 8 bit CPUWhile stock lasts 14.95 ea.

UV "Eprom" Eraser

~ Model UVS-11E S69.95

ModelS-52T... S325.00

NON-LINEAR SYSTEMS. INC/flK

TOUCHY-TEST 20

DIGITAL *._.»»-

MULTIMETER $31 995

* BECKMANc$£ DIGITAL MULTIMETERS

>Jo TECH 300 Digital Multimeter $110

** TECH 310 Digital Multimeter S140

TECH 330 Digital Multimeter S189

VC-201 Vinyl Carrying Case 510

DC-202 Deluxe Carrying Case 524

HV-211 High Voltage Probe 535

RP-221 RP Probe 535

Ct-231 AC Current Clamp 542

DL-241 Delxue Test Lead Kit S10

TL-242 Square Test Leads S6

INTERSYSTEMS

The Preferred S-100 Box

The new Series II CPU Board features a AMHz Z-80A CPU and full-feature frontpane!. 20-slot actively terminated mother-board, with 25 amp power supply (50/60 Hzoperation, incl. 68 cfm fan).DPS-1, List $1795

ACP Price

$1499

SYSTEM 2A

with Z-80A CPU

MHz, 64K RAM, I/O Board, 20 slots, front

panel, double density disk controller

board. Full 1-year warranty.

List $3795 ACP Price $2995

• Z-80A CPU 4 MHz

• 5 user programmable function keys■ 82 Keys with numeric keypad

• 160x100 n

NEC

PC-8000 SeriesMicrocomputer System.

NEW

INTRO

PRICING

$1099.00

mpuler w'32KRAM . SI295.00I PC-8012A l;0 Unit w-32K RAM,

, Expansion slots 795.00

PCB031A Dual Mini-Disk Drive Unit 1295.00

PC-8032A Add-On Dual MInl-Dlsk

Drive Unit 1095.00

I PC-8023A Impact Matrix Printer.

I Tractor/Friction Feed 660.00

[ PC-8094A Cable for PCB023A Printer 49,95

JB-1201M(A) High Resolution

Green Monitor 265.00

JC-1202DH(A) High Resolution

Color Monitor w/RGB Input 1195.00

PC-8091A RGB Cable lor

JC-1202DH(A) Color Monitor 19.95

3asic Language Learning Guide

3C-8001A Microcomputer Reference Manual ....

PC-B012A I/O Unit User's Manual

| PC-B031A Dual Disk User's Manual

239.00

1049,00

17.9519.9519.95

RETAIL STORES OPEN MON-SAT

MICROPROCESSORS

Z8001 16bittc>8Mb. . .5189.00Z8002 16 bit to64K .... 149.00

280 995

Z80A 13.95

F-8 138501 16.95

2650 16.95

CD 1802 9.75

B080A 4,75

808DA-4MH! 19 95

SALE 8085 14.95

6008-1 14 95

2901 9 90

2901A 14 95

2903 4-bilSupersl.ee 29 95

TMS9900JL 49.95

CP160O ... 39.95

6502 9.95

65Q2A ... ... 16.95

IM61O0 29 95

6800 11-75

63O0B 2 0 MHz 19 95

6802P .... 1795

8035 14.95

8039 19-95

INS8073N 24.95

8755 4995

8748 69 95

6B09 3795

8086 69 95

ADVANCED SUPPORT

AM9511 Anth, Processor .175.00

9512 Anth Processor 175.00

9513 Umv, Timing . .. 79.95AM9517 DMA Controller 18 95AM9519 Universal Interrupt 18 95

Z-80 SUPPORT CHIPS

Z80-PIO 2 5 MHz 8 75

2S0A-PIO 40MHz .. 12.95

Z80-CTC 2 5 MHz 8.75

Z60A-CTC 4 0 MHz 12 95

ZB0-DMA 2.5 MHz . 29 95

Z60A-DMA 4.0 MHz.. 36.95

Ze0-SIO/0 2 5 MHz.... 35.95

Z80A-SIO/0 4 0 MHZ 39.40

Z80-SIO/1 2 5 MHz... 35.95

Z80A-SIO/1 4 0 MHz 39.40

ZS0-SIO.2 2.5 MHz ... .35 95

280-SlO 2 4 0 MHz 39 40

8080/8085 SUPPORT

8155/8156 I/O 24.95

8755 I/O with Eprom 84.95

8202 Dyn Ram Com 34 95

B205.74S 138 Decoder ,., 3 958212 8 btt I/O 2 75

82T4 Priority Ini 5.25

B216 Bus Driver 2.75

8224ClockGen 295.

B224-4(4MHz> 9.75

8226 Bus Driver 2.95

BT26 Bus Drivei 2 95

B22BSy9. Control 4.50

823BSys Cont 5.50

8243 HO Exp . . . 9.50

8250Asyn.Comm 15.95

8251 Prog I/O ... 5.95

B253 Int. Timer . 12.95

8255 Proo. I/O ... 6.50

9257 P-o(j DMA 16.95

8259 Prog Int 15 95

8275 CRT Coniroller 45 95

8279 Prog. Keyboard 15.95

6800 SUPPORT CHIPS

6810 128 « 8 Ram 4.75

6B20 . .6.50

6821 6 50

6828 Priority Int . 10.75

5834-1 512 ■ 8 Eprom .... 16.956B45.HD46505CHTCortl. ..29.95

6847 Color CRT 29,95

6850 ACIA. . . ...5.95

6B52 Se'ial Adapter . . 5.95

6B60 Modem .. . 10 95

>?££2 '.'adulator . 11.95

6871A l.OMHz OSC 25.95

6875 ... 6.95

6880BusDnver 2.19

MC684S8 19.95

68047 24.95

6502 SUPPORT CHIPS

6520 PIA 7 50

6522 Mull . .1 1.95

6530-002.003.004.005 .. .21.95

6532 ... . 19-95

6551 . 19.95

BIPOLAR PROMS

We doCustom Programming

82S23'6330/56O0/74S1B8 4.25

82S115(512x8,TS 12.95

82S123,'56lO'74S28B|32x8iTS. 4.2582S126'5603'74S387|256x4)OC 4.2582S129 5623'74S287 (256x4|TS 4.2582S130..,5604.74S570(5l2x4)OC 6.50

82S13U74S571 (512x4)TS 6.95

82S137/74S573(1024xd)TS . . . 12.9582S141/3624/74S474 (512xB)TS 12.95

82S147/74S472(512x8)TS 12.95

74S47iy6309(256x6)TS 7.95

MOS PROMS

2764 (BKxBlTS 89.95

2732|4Kx8)TS 16.95

2716/2518;5V(2Kx8lTS B.95

TMS2716, = 5V. 12V 17.95

275B.5V, (450N5J 7.50

2708 UJ50N5I 5,75

270B (650rJsl 5.25

1702A 5.75

MM5203AQ 14.50

MM5204Q 9.95

CHARACTER QEN.

2513-001 (5V)Upper 9,50

2513-005 (5V| Lower 10.95

2513-ADM3 [SV) Lower.... 14.95MCM88710 Ascll Shifted 12.95MCM66740 Math Symbol 13.45MCM66750 Alpha Control 13.45

UARTS/BAUD RATE

TR1602BI5V I2vi 395

AY51013I5V. 12VI A.95

AV5101AA/1612 (5-'4Vi 6 95

AY51015A/ia63 |5VI 6 95

IM6402 7.95

IM6403 8.95

2350 USPT 9 95

1671BAs!'os 2495

SALE TR1472B S.SS

MC1A41 1 11.95

4702 1rt95

WD1941 9 9^

COM 5016 16.95

INS 8250 15.96

KEYBOARD ENCODERS

AY5-2376 13.75

AY5-3600 13.75

STATIC RAMS

? 1L02-450ns /sfrLfcN2IL02 250ns (»A02

1 2, KJ&S

1 301 59375

25-991 251 553 65ZS5

res

211JNI450WS.1

3.75

3.50

3 25.

21 1.1L-J50ns l4045l

Z114L-450ns |40A5)

4 ("5

4 2F.

3.95

.lO'i-l ^50 ns

8 95

7 50

6 9C

4044 4 50ns.

8 75

f98

EWM4402

7 95

7 25

S2h

AMD9140/41

10.95

10 25

9 25

AMD9130/31

11 95

»0 2E

1101

195

175

p?i:'!):-*):i425[45fisi

8 35

65IQ IK . 1 CMOS

7 95

7 95

8 95

G 95

934 1[i

')<){!

'i.-i'-

f)f>0

FLOPPY DISK I/O

1771-01 8"& Minillopriy .24.9

1781 Dual Floppy 29 9

1791-01 Dual Floppy 36 9

1791-02 Dual Floppy 44.S

1793 DO. DS Floppy ..... 44.5

1797 DD, DS Floppy 54.5

1691 Data Separator . . . 1B.S2143ClockGen 1B.9

DYNAMIC RAMS

416/4116 16K(16Pin)Setol8416s200N541158K(16Pin)

4050 4K, 1 [18 P.ni

2.492495

2.49■195

4060-IK » 1 (22 Pin)

4 95

4096-IK . 1 (16 Pjnl

2104 -IK , 1 |16P.nl

4027 4Kx 1 (16Pinl,'UPD414

3 95

4 75

. .4.95

52G1 195 RA\f "035262 1 95 0*+^ 40O8L

113. 511 J?AMS USS

$19.95 6002

.95

7 951 50

SOCKETS

* Pin.

| Wire Wrap 3 Laval

Lo-Pro Solderlail

Tin

Gold

14

151920

3236

35

1

IB

59

84

69

99

2J

79

24

38

65

i 20

43

1 10

1 49

3G

SO

1 -SO

ZERO INSERTION FORCE

16P.n S^50 24P.n S7 50 40 Fin S1025

LED READOUTS

Pin Hi Jta C*i

□ .704 300 Red

0.707 300 Red

FN03S? 35/ tel

FND5Q1 SOD Red

FN0503I500I 500 Red

FNDS07|510, 500 Red

Crnvi Catnsdei + n

-■■D'-.i'"

3 Red

FHD530 500 Gree

FMD550 500 Dran

FHDB0318001 SOO Red

friMDrieiO) 800 Red

rP5082-'340 600 Red

H=5082'300 600 Bed

IP50B2-7731 300 Red

MAN2A

MAN10AKAN] 061

WMV:vi

300 Red300 Giccn300 Green

, OvsrHan CA L-

IC SPECIAL PURCHASE

82S09 64x9 Ram 8.95

DPB304 Octal Driver 2.95

DAC86EXD/ACorw 6.95

MC1650 Hi Speed AID 7 95

MC6852SSDA 3.49

HC1014S 16x4 ECL Ram 4 50

MK38507F8CPU ^.95

MK3853 Static Mem I/O 4.95

SN75136 .46 78M06 .49

MC10210 .89 79M06 .49

LM339 .79 74157 .49

LM710CN .29 74161 .49

LM711CN .29 74C74 ,39

ICM ,'O-ir. Precision StonWalCh .... 23 95

ICM 7207 Oscillalor Conttoller 7.50

Seven Decade Counter 7208 IS.95

MC14433P3'; Digit A/0 Converter 13 95

ICL 821 1 Voltaqe Reference 1 95

LM IB50N Ground Fault IC 3/1 00

LM 290ON Quad Amplifier 2/1 00

LM 2917N Fret), to Volt Conv 2/1 99

AY-3-3550 4i« digit DMM 24 95

AY-5-3507 40MHz DVM 9 95

MEM 4963 Mosfet Smim. DmocIO' 7 95

27S08 32 . 8 Prom (IM 56001 2 95_

ULN 2003A 7 channel Driver 99

MCM 14505 64 bit Sialic Ram 695

MOC 1003 (4N2S|Opto Coupler 3/1.00

SPX33 Oplo Coupler 3/1.00

IH 5045 CMOS Switch DBST 4.50

UA3045 Trans. Array 1.25

TR 1402 A U ART 1,95

MJ< 1007 Dyn. Mem. Shift Reg 3.95

5318 TV Ch, Disp. Circuit 4.5D

80B0A 8 Bit CPU 4.95

6700 CJ B Bit A/D 9.95

MM52BO/VPD411/C2 107/TMS4O60/

4Kxl Dynamic 22 Pin RAM 1.75

6604/VPD 414/4027/2660/MK 4096/

4Kx1 Dynamic 16 Pin 1.95

■520/25

1488/1489 .2/199

LM323K 495

MC1372 B.95

i/M'J29rV4A/B . .2 95

A 4558 3/1 99

RC4136.

2/1.'

FLOPPY CHIP SET

Double Density

Double Sided Includes- 1797

$79.95/set -Ml

A/D CONVERTERS

87Q1 10 hit Binary

9400 ViHI lo Freq Conv 7

8750 3'; Digit BCD 13

1408L6 6 bil 3

1408L8 8 bil 5

DACOI D to A 5,

DAC08 9

DAC 100 9

TV CHIPS/SOUND

AY38500-1 6 Games B/W 4

AY3851 5 Colo- Convener 2

AY38603-1 Roadrace G.iAY38606-I Wipeoul GanAY38607-' Shootmy GalAY38910 Sound GeneralSN76477 Tl Sound Gene.MM5320-21 TV Synch G!.'M53C9 P'escalerLM1889 PF ModulatorMM 57100 NSC ColO' TVMM57104 Clock Gen

m&p Modulate"

13.5022 0013 50

29 95

WAVEFORM GEN.

803B Function Gen.

MC4024VCO

LM566 VCO 1 95

XR2206 Function Generator 5.25

SHIFT REGISTERS

2504V

2507V

2517V

2524V

2525 .

2527

2528

2529

2533

2.95

MM500H 50

MM5056N 2-95

MM5060N 2 95

2510A 195

5 95

9.95

334:

CTS DIPSWITCHES

CTS206-2 1 75 CTS206-7 1 75

CTS206-4 l 75 CTS206-8 1 95

CTS206-5 1 75 CTS206-9 1 95

CTS206-6 1 75 CTS206-10 1 95

CONNECTORS (GOLD)

DB25P(RS232I 3 25

DB25S Female 375

Hood 1 25

Set w/Hood. Sale S/50

22/44 W/W. S.T.KIM 2.95

43/86 WAV. S/T, MQT 6 50

5O/1C0 S-100 Connector W/W 4 95

50/100 S-100 Connector Sri 3 95

S-100 Hound Board $34,95

8O80ACPU 34 95

32K Sialic RAM (21 141 39.95

BK Eprom (27081

2708/2716 Eprom

ACP Proto 8d

Vecior 8800 Proto

Vector 8B03 11 slot ME

ACP Exlender w/Conn .

13 Slol MotherBoard(WMC)32.95

9SlolMolherBoard|WMC) 29 95

SSiotMolheJiExpandabie) 34.95

Floppy PCB (8-SriUGARP 3995

SI 00IAY5-69101 Sound Bd 34 95Apple Sound Bd 24.95

349522 9522.20299518.95

LM3B0 1 25

VERBATIM DISKETTES

100% CERTIFIED ERROR-FREE!

25 THICKS. DOUBLE DENSITY. SINGLE-SIDED S'<

PHICE'BOX 10I299S>123 95S2995

TYPE DESCRIPTION PI

525-01 Salt Sectored TRS BO etc525-10 10 Hole Hard NS Aprjie etc525-16 16 HtfeHarrJ Mcropoiis

■ i.) i II THICK DOUBLE DENSITY- SINCLE SIDEI

S'A" W/HUB REPHFOHCEMENT PIIHG577-01 Soft Sectored. TRS BO. etc

577-tO 10 Hole Hard NS Ancle ere

■577-16 16 Hole Hard MicrWOliS

• 40 TRACKS. DOUBLE SIDED DOUBLE DENSITY 5'.S50-P1 Soft Sectored SA 450 MPI 52550-10 10 Mole Hard BASF WANGCO550-16 16 Hole Hard Mao'

• BM 100% CERTIFIED DISKETTESFO8O0-O1 Soli Single Oensilv. 3740 S3351FO8O0-32 32 Hard Single Density Strug 3351FDB02-01 Soft OouOle Density 3740 4481FO85D-01 Soil OouB^ Sided. Ooot* Oensny 3740 49BI

VOLUME DEALER PRICING AVAILABLEWE ALSO STOCK DYSAN-CALL

^PRINTERS

rTT EPSON

•*<

MX-BO $495.00

MX-80FT 595,00

MX-100 895.00

MX-70 425.00

Centronics 739 799.00

Vista V-300/25 ops . ....1495.00

V-300/45cps 1795.00

Malibu 165 1995.00

AnndoK 9500/9501 1450.00

Base II 800 MST 549.00

\TERMINALS

..S799

..1849

S995

AddS Viewpoint S599

Ampex Dialog 80 J1025

Soroc IO120 $699

IQ135 $899

IQ140 1149.00

ef

SANYO

MONITORS"

vy_M4509 9"BWSale Price 159.95OM5012 12'B/W 239.00

DM5112l2"Green 249.00

DM6013 13-Color 415.00

NEC Green 259.00

AMDEK/LEEDEX Video 100149.00AMDEK/LEEDEX13"Color 399,00AMKEKJLEEDEX 12' Green 179.00

S32 253225

32 25

(3695$3895139 35

TERMS: Use check. M/C, VISA.AMEX, CB. or COD COD requires25% deposit. Charge Orders pleaseinclude eipiralion date. Foreign payU.S. Funds. Order by phone, mailTWX. MINIMUM $1000. Pleaseelude magazine issue and phoneSHIPPING: USA add S2.00 for f2 lbs. For surface add 30C tor attional lbs. For air add 70C lor a(lional lbs FOREIGN: Add 10% Stping and handling. CQD's $1.85 extra,Not responsible loi lypos. Someilems subject to prior sate, We reserve right to limit quantities, somiitems subiect to precious metal adderRetail pricing may vary from MaiOrder. Wo reserve the right to suoslilule manulacturer.

STORE Hi! 131Q-B E rj:STORE »2: 542 W. Tri

"Retail prices may vary.

'. CA 95131 • (408) 946-7010

P.O. Box 17329 Irvine, Calif. 92713

Direct Order Lines: (714) 558-8813

(800) 854-8230 or (800) 854-8241

Circle 8 on Inquiry card.

FOR INTERNATIONAL ORDERS:1310 E. Edinger (714) 953-06U4Santa Ana. CA92705 TWX:910-S95-1565

5N7400NSN7401NSN7402N5N7403NSN7404N5N7405NSN7406NSN7407NSN7408NSN7409NSN7410NSN7411NSN7412NSN7413NSN7414NSN7416NSN7417NSN7420NSN7421NSN7422N5N7423NSN7425NSN7426NSN7427NSN7428NSN7430NSN7432NSN7437IMSN743BNSN7439NSN7440N5N7441NSN7442NSN7443NSN7444NSN7445NSN7446NSN7447NSN7448NSN7450NSN7451NSN7453NSN7454NSN7459ASN7460NSN7470N

74LS0O74LS0174LS0274LS0374LS0474LS0574 L SOB74LS0974LS1074LS1174LS1274LS1374LS1474LS1574 L 52074LS2174LS2274LS2674L52774LS2874LS3074LS3274 L 53374L53774LS3874LS4074LS4274LS4774LS4874 L 54974L55174LSS474LS5574LS7374L57474LS7574L57674 LS7874LS8374 L 58574LS8674 L 590

74SO074S0274S0374S047450574 SOS7450974S1074S1174515745207452274S3074S32745 3874S4074551745647456574S747458674511274SU3745114

7400

SN7472N

SN7473N

5N7474N

SN7475N

SN7476N

SN7479N

SN74B0N

SN7482N

SN7483N

SN74B5IN

SN7486N

SN7489N

SN7490N

SN7491N

SN7492N

SN7493N

SN7494N

SN7495N

SN7496N

SN7497N

SN74100N

SN74104N

SN74105N

SN 74107 N

SN74109N

SN74116N

SN74121N

SN74122N

SN74123N

SN74125N

SN74126N

SN74132N

SN74136N

SN74141N

SN74142N

SN74143N

SN74144N

SN 74145 N

SN74147N

SN74148N

SN74150N

SN741S1N

SN74152N

SN741S3N

SN74154N

SN74155N

lUII I

SN74156NSN74157NSN74160NSN74161NSN74162NSN74163NSN74164NSN74165N5N74166NSN74167NSN74170NSN74172NSN74173NSN74174NSN74175NSN74176N5N74177NSN74179NSN74180NSN74181NSN74182NSN74184N5N74185NSN74190NSN74191NSN 74192 NSN74193NSN74194NSN74195NSN74196NSN74197NSN74I98NSN74199NSN 74221NSN 74251N5N74276N5N74279NSN 74283 N5 N 74284 NSN742B5N5N74365NSN74366NSN74367N5N74368NSN 74390 NSN74393N

74LS

74L59274LS9374LS9574LS9674LS10774LS10974LS11274LS11374LS11474L512274LS12374LS12574LS12674LS13274LS13374LS13674L513B74L513974LS1S174LS15374L515474LS15574LS1S674LS15774LS15874LS16Q74LS16174LS16274LS16374LS16474LS16574LS16874LS16974 LSI 7074 LSI 7374 LSI 7474LS17574LS18174LS19074LS191

1.151.15

1.151.15

74LS192

74LS19374LS194

74LS19574LS19774LS22174LS24074LS24174LS24274LS24374 L 524474 L 524574LS24774LS24874LS24974LS25174LS2S374LS25774LS25874LS26074LS26674LS27374LS27974LS28374L529074LS29374L529874LS35274LS35374LS36574LS36674LS36774LS36874LS37374 LS37474LS37574 L 538574LS39374LS39974LS67081LS9581LS97

74S

74SI24

74513374513474S13574S13674S13874513974S14074S15174515374S15774S15S74515074S17474S17574 S18874519474519S74S19674S24074S241745242

2.951.951.951.952.952.95125

74S24374524474S25174525374S25774 S 25874 S 26074528074S28774S28874537374S37474S38774S47174S47274547374S47474S47574557074S57174S57274S57374S94Q74S941

2.951.191.191.19

2.492.492.49

2.9510.9510.9510.9512.9512.955.955.959.959.953.153.15

4-Digit 16 SegmentAlphanumeric Intelligent

Display withMemory, Recorder, Driver

End-siflcknblB. 4-charBciar packago, High con-trast, IGOmil high, magnified monolithiccharacters. 64-Chaiacter ASCII format. Built-inmemory, docodar, mu I lip lexer and driver*. Diroclaccess to each digit independently and asyn-chronously. Five volt logic. TTL compatible. Fivavolt power supply only. Independent cursor func-tion. Siie; 1"L x l-3/16"H x .225"0.DL-1416Alphonumoric Display S19.95 en.

rn

10-SegmentBargraph Displays

(with On-Board Driver IC-Chip)

Size: 2ML x 7/8"H x 3/16"D

Bar or dot display mode externally selectable by user.Packages are end-stackoblo for expanded displays. Can bocascaded to 10 arrays (100 bargraph elements). LEO currentprogrammable from 2mA 1o 30mA. Stable internal voltagereference forfullscalaanalDginputB from 1.2 to 12V. Each LGDoutput of driver IC with axtornai access. Siia; 2"x7/8"x3/16".NSM3914 Linear Function (10 bars red) 16.96

NSM39146 Linear Function (6 bars green/4 red) 6.96

NSM391E Logarithmic Function (10 bars red) E.96

NSM39168 Logerlthmlc Func. (6 grn./2 yoll./2 rd.l 6.96NSM3916 VU-Matar Function M0 bars red) 6.96

NSM39168 VU-MetorFunc.tBgrn./2yall./2rd.) 6.96

DISCRETE LEDS

XC556R .200" red

XC556G .200" green

XC556Y .200" yellow

XC556C .200" clear

XC22R .200" red

XC22G .200" green

XC22Y .200" yellow

MV10B .170" red

MV50 .085" red

XC209R .125" red

XC209G .125" green

XC209Y .125" yellow

XC526R .185" red

XC526G .185" green

XC526Y .185" yellow

XC526C .185" clear

C.A.

D.D. - DType

MAN 1MAN 2MAN 3MAN 52MAN 54MAN 71MAN 72MAN 74MAN 82MAN 84MAN 3620MAN 3630MAN 3640MAN 4610MAN 6510MAN 6630MAN 6640MAN 6650MAN 6650MAN 6710MAN 6740MAN 6750DLO304DLO307DLG500

Con-

|.200(Tiy.Q Red/Green

Diffused Si-Color LEDPart No. 1-99 100+

RL-2 . .$.39ea.or3/S1.00

PolarisC.A.—r5x7 D.hC.C.—r.C.A.—gC.C.-gC.A.—rC.A.-rC.C.—nC.A.—iC.C.—yC.A.—cC.A.—c

c.c— C

C.A.-c

C.A.—orange—DD .560

C.A.

C.C—c

C.C.-c

C.A.

C.A.

c.c-c.c-c.c.

C.A.—c

c.c-

Price

2.95

—orange

: 1

-DD .orange t 1—orange-red—DD

-red—DD

-red * 1

orange

Type

DLG507

DL704

DL707

DL728

DL741

DL747

DL750

DL0847

DLO850

DL33B

FND358

FND357

FND500

FND507

HDSP-3401

HDSP-3403

H DSP-3406

5082-7751

5082-7760

5082-7300

5082-7302

5082-7340

4N28

LIT-1

MOC3010

RHD — Right Hand Decimal

Ht

.500

.600

.110

Polarity

C.A.-green

C.C—red

C.A.—red

C.C—red

C.A.— red

C.A.—red

C.C—red

C.A.—orange

C.C. -orange

C.C—red

C.C. i 1 .357

C.C. .357

C.C (FND503) ,5oo

C.A. (FND510) .500

C.A.-red .800

C.C.-red .800

C.C. red +1 .800

CA..R.H.D.— red .430

C.C.R.H.D.—red .430

4x7 Numeric (RHD).600

4x7Numeric(LHD).600

4x7Hxdcl.(0-9/A-F) .600

Photo XsfstorOpto-lsol.

Photo Xsistor Opto-lsol. .69

Optically Isol.TrlacDriver 1.25

Price1.251.251.251.491.251.49

1.49

1.501.501.501.251.2522.0022.0022.50

SOCKETS

PartNo. Pins Price

214-3339 14 pin 5.95216-3340 16 pin 6.49218-3341 18 pin 7.95220-3342 20 pin 8,95

Test

RECEPTACLES

t«xtool sockets

ZERO INSERTION FORCE

Nickel Boron PlatingG.F. PSF Plastic BodyFor testing IC'sPartlMo. Pins Price

222-3343 22 pin 9.95224-3344 24 pin 9.75228-3345 28 pin 11.95240-3346 40 pin 12.95

LOW PROFILE(TIN) SOCKETS

8 pin LP

14 pin LP

16 pin LP

IB pin LP

20 pin LP

22 pin LP

24 pin LP

28 Pin LP

36 pin LP

SOLDERTAIL (GOLD)STANDARD

8 pin 5G14 pin SG16 pin SG18 pin SG24 Pin SG28 pin SG36 pin SG40 pin SG

* Nicket Boron Plating

* G.F. PSF Plastic Body

* Wire Wrap ContactsPart No. Pins Price

214-3592 14 pin 9.75216-3593 16 pin 9.95218-3594 18 pin 10.95220-3595 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

SOLDERTAILSTANDARD (TIN)

24 pin ST28 pin 5T36 pin ST

8 pin WW10 pin WW14 pin WW

16 pin WW18 pin WW20 pin WW22 pin WW24 pin WW28 pin WW36 pin WW40 pin WW

WIRE WRAP SOCKETS(GOLD) LEVEL #3

Part No. Function

70451PI CMOS Precision Timer

7045EV/KII- Stopwatch Chip, XTL

7106CPL 3i/i Digit A/D (LCD Drive)

7106EV/Klt* IC, Circuit Board. Display

7107CPL 3Vi Digit A/D (LED Drive,

7107EV/KII' IC, Circuit Board, Display

7116CPL 3Vi Digit A/D LCD Dls. HLD.

7117CPL 3>« Digit A/D LED Dis. HLD.

7201IDR Low Battery Volt Indicator

7205IPG CMOS LED Stopwatch/Timer

720SEV/KU* Stopwatch Chip, XTL

7206CJPE Tone Generator

7206CEV/Klt* Tone Generator Chip, XTL

7207AIPD Oscillator Controller

7207AEV/KH" Freq. Counter Chip, XTL

7208IPI Seven Decade Counter

7209IPA Clock Generator

7215IPG 4 Func. CMOS Stopwatch CKT

7215EV/KU* 4 Func. Stopwatch Chip, XTL

7216AIJI 8-Dlglt Univ. Counter C.A.

7216CIJI B-Dlglt Frea. Counter C.A.

7216DIPI 8-Dlglt Freq. Counter C.C.

72I7IJI 4-Dlgit LED Up/Down Counter

721BCUI 8-Dlglt Univ. LED Drive

7224IPL LCD 4'/i Digit Up Counter DRI

7226AIJL 8-Dlglt Univ. Counter

7226AEV/KU- 5 Function Counter Chip, XTL

7240IJE CMOS Bin Prog. Timer/Counter

7242IJA CMOS DIWde-by-256 RC Timer

7250IJE CMOS BCD Prog. Tlmor/Counte,

7260IJE CMOS BCD Prog. Tlmer/Countei

7555IPA CMOS 555 Timer (8 pin)

7556IPD CMOS 556 Timer (14 pin)

7611BCPA CMOS Op Amp Comparator

7612BCPA CMOS Op Amp Ext. Cmvr.

7621BCPA CMOS Dual Op Amp Comp.

7631CCPE CMOS Trl Op Amp Comp.

7641CCPD CMOS Quad Op Amp Comp

7642CCPD CMOS Quad Op Amp Comp

7660CPA Voltage Converter

B038CCPD Waveform Generator

8048CCPE Monolithic Logarithmic Am

8069CCQ 5Qppm Band-GAP Volt Ref.

8211CPA Volt Re(/lnd!cator

8212CPA Volt Ret/indicator

PricB

14.95

24.95

16.95

34.95

15.95

29.95

18.95

17.95

2.25

12.95

19.95

5.15

12.95

6.50

13.95

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

S.2S

1.45

2.20

5MV 2.25

5MV 2.95

5MV 3.95

10MV 5.35

10MV 7.50

10MV 7.50

2.95

4.95

21.60

Hode 2.50

2.95

2.95

74C00

74C0274C0474C0874C1074C1474C2074C3074C4274C4874C7374C7474C8574C8674C8974C9074C93

74C9574C10774C15174 C15474C15774C16074C16174C16274C16374 C16474C17374 C17474C17574C19274C19374 C195

74C

1.59

74C22174C24074C24474C37374C37474C90174C90374C91174C91274C91574C91774C92274C92374C92574C926B0C9580C97

2.252.252.492.59

10.955,495.757.507.50

LH00O2CN

LM10CLH

LM11CLH

LH0070-OH

TL071CP

TL072CP

TL074CN

LH0O82CD 2

TL0B2CP

TL0B4CN

LH0094CD :

LM300M

LM301CN

LM302H

LM304H

LM305H

LM307CN

LM308CN

LM309H

LM309K

LM310CN

LM311/CN

LM312H

LM317MP

LM317T

LM317K

LM318CN

LM319N

LM320K-5

LM320K-12

LM320K-15

LM320T-5

LM320T-12

LM320T-1S

LM323K

LM324N

LM329DZ

LM331N

LM334Z

LM335Z

LM336Z

LM337T

LM337MP

LM338K

LM339N

LM340K-5

LM340K-12

LM340K-15

LINEAR

LM340T-5 1.25LM340T-12 1.25LM340T-15 1.25LM341P-5 .75

LM341P-12 .75LM 34 IP-15 .75LM342P-5 .69

LM342P-12 .69LM342P-15 .69LM34BNLM350KLF351NLF353NLF3SSNLF356NLM358NLM359NLM370N

5.75

1.10

LM373N

LM377N

LM3B0N

LM381N

LM382N

LM384N

LM386N-3

LM387N

LM3B9N

LM392N

LF39BN

LM399H

TL494CN

TL496CP

NE510A

NE529A

NE531H

NE536H

NES40H

NE544N

NE550A

NES55V

LM556N

NE564N

LM565N

LM566CN

LM567V

NES70N

LM702H

LM703CN

LM709N

LM710N

LM7UN

LM723N

LM733N

LM739N

LM741CN

MC1741SCG

LM747N

LM748N

LM1014N

LM1310N

LM1458CN

LM14SBN

LM1489N

LM1496N

LM1S56V

LM1800N

LM3871N

LM1872N

LM1B77N-9

LM1B89N

LM1896N

LM2002T

LM2877P

LM2878P

LM2896P-1

LM3189N

LM39Q0N

LM3905CN

LM3909N

LM3914N

LM39J5N

LM3916N

RC4136N

RC4151NB

RC4194TK

RC4195TK

LM45O0A

ICLS038B

LM13080N

LM13600N

75138 N

75450N

754S1CN

75492

CA3O10HCA3013HCA3023HCA3035H

CA3039HCA3046NCA3059N

CD4000CD4001CD4002CD400SCD4007CD4009CD4010CD4011CD4012CD4013CD4014CD4015CD4016CD4017CD4018C D4019C D4020CD4021CD4022CD4023CD4024CO4025CD4026CD4027CD4028CD4Q29CD4030CD4034CD4035CD4040

2.153.252.491.351.303.25

CA-LINEAR

3.25

CA3060NCA3080HCA3081NCA3082NCA3083NCA3086N

2.002.00

1.60

CA3089NCA3096NCA3130HCA3140HCA3160HCA3401NCA3600N

1/4 WATT RESISTOR ASSORTMENTS -5%

CD-CMOS

CD404)CD4042CD4043CD4044CD4046CD4047CD4048CD4049CD4050CD4051CD4052CD4053CD4056CD4059CD4060CD4066CD4068CD4069CD4070CD407ICD4072CD4073CD4075CD4076C D40/8CD4081CD4082CD4093

2.959.951.49

CD 4098

CD4506

CO4507

C D450B

CD4510

CD4511

CD4S12

CD4514

CD45I5

CD4516

CD4S18

CD4519

CD4520

CD4526

CD4S28

CD4529

CD4543

CD4562

CD4566

CD45B3

CD4584

CD4723

CD4724

MC14409

MC14410

MC14411

MC14412

MC14419

MC14433

MC14538

MC14541

ASST

1

5ea.

10 Ohn27 Ohn

12 Ohn33 Ohn

15 Ohn39 Ohn

18 Ohn47 Ohn

22 Ohm

56 Ohm

50 pes.

$1.95

ASST

2

5ea.

68 Ohn180 Ohn

82 Ohn

220 Ohn

100 Ohn270 Ohn

120 Ohn330 Ohn

150 Ohm

390 Ohm

50 pes.

$1.95

ASST

3

5ea.

470 OhnI.2K

560 Ohn1.5K

680 Ohn1.8K

820 Ohn2.2K

IK2./K

50 pes.

$1.95

ASST

4

5ea.

3.3K8.2K

3.9 K10K

4.7K12K

5.6K15K

G.8K18K

50 pes.

$1.95

ASST

5

Boa.

22K56K

27K

68K

33KS2K

39K100K

47K120K

50 pes.

$1.95

ASST

6

5ea.

150 K390K

I80K470K

220K

560 K

270K

680K

330KB20K

50 pes.

$1.95

ASST

7

5ea.

1M

2.7M

1.2M3.3M

1.5M3.9M

1.8M4.7M

2.2M5.6M

50 pes.

$1.95

CAPACITOR CORNER

50 VOLT CERAMIC DISC CAPACITORS

Value 1-9 10-99 100+ Value 1-9 10-99 100-t

10 pf .08 .06 .05 -OOlpF . .08 .06 .05

22 pf .08 .06 .05 .0047uF .08 .06 .05

47 pf .08 .06 .05 .Ol^F .08 .06 .05

100 pt .08 .06 .05 -022yF .09 .07 .06

220 pf .08 .06 .05 .047uF .09 .07 .06

470 pf .08 .06 .05 .1/iF .15 .12 .10

100 VOLT MYLAR FILM CAPACITORS

.OOlmf .12 .10 .07 I .022mf .13 .11 .08

.0022mt .12 .10 .07 .047m( .21 .17 .13

,0047mt .12 .10 .07 .lmt .27 .23 .17

.Olrnf .12 .10 .07 I .22mt .33 .27 .22

+20% DIPPED TANTALUMS (Solid) CAPACITORS

ASST.8R

Includes Resistor Assts. 1-7 (350 pes.)

$10.95 ea.

.1/35V. 15/35V. 22/35V.33/35V.47/35V.68/35V1.0/3SV

.39

.29

.39 .34 .29

1.5/35V2.2/35V3.3/25V4.7/25V6.8/25V15/25V22/6V

.41

.37

.29

.SI .45 .34

.79 .69 .551.39 1,25 .95

1.952.7911,95

1.95

17.9518.9515.9515.95

MINI. ALUMINUM ELECTROLYTIC CAPACITORS

S10.00 Min. Order - U.S. Funds OnlyCalif. Residents Add 6% Sales TaxPostage-Add 5% plusSI Insurance

;CATALOGS

J a■HM»H;H?II«H

Spec Sheets - 25rf

Send 86(( Postage for your

FREE 1982 JAMECO CATALOG

PHONE

ORDERS

WELCOME(415) 592-8097

MAIL ORDER ELECTRONICS - WORLDWIDE

1355 SHOREWAY ROAD, BELMONT, CA 94002

PRICES SUBJECT TO CHANGE

Axial

.47/50V

1.0/50V

3.3/50 V

4.7/25V

10/25V

10/50V

22/25V

22/50V

47/25V

47/S0V

1O0/25V

10Q/S0V

220/25V

220/50V

470/25V

1000/16V

2200/16V

1-99 100-499 500+

.18 .15 .11

Radial

.47/25V.47/50V1.0/16V1.0/25 V1.0/SOV4.7/16V4.7/25V4.7/50V10/16 V10/25V10/50V47/SOV100/16V100/25V100/50V220/16 V4 70/25 V

1-99 100-499 MW+

.15 .13 .12

.15 .13 .12

.25 .23 .21

.35 .31 .27-

516 BYTE October 1981

Circle 189 on inquiry card.

/I

slSductorClock Modules

12V DC

AUTOMOTIVE/

INSTRUMENT

CLOCK

APPLICATIONS:

vdasri i

itoc

et auto/

• AfterRV clocks

• Aircraft-marine elks.

• 12VDC oper. instru.

• Portable/battery

nts.

Features:Bright 0.3" green display. Internal crystal time-base. 10.5 sec./day accur. Auto.display brightness controllogic. Display color filterable to blue, blue-green, green &yellow. Complete-just add switches and lens.

MA 1003 Module c3.05»lxi.75"hx^8»d) . $ 16.95

CLOCK MODULES

Red Digital LED Clock Module

Dig. LED Alarm Clock/Thermometerlital LED Clock/Timer

Red Digital LED Clock & Xformer

Red Digital LED ClockMA1032 CBA .5" Digital LCD ClockMA1043 .7" Green Digital LED ClockTRANSFORMERS102-P20 Xformer for MAI 023,1043 Si 5036 Mods.102-P22 Xformer for MA1026 Clock Modules102-P24 Xformer (or MA1010 Clock Modules

MA1023 .MA102G .MA5036 .3" Red DigMA1002 .1MA1010 .

B.9518.956.959.957.9517.958.95

3.493.493.49

8 OHM SPEAKER

254" -8 Ohm -.25 watt

A0201

S1.25ea. 2/S1.95ea. 1D/S7.95ea.

BATTERY HOLDER

•Holds 2 ea. C cells

• Aluminum Case

•5" leads bh-801159

$.45 each 10/S3.95

BATTERYHOLDER

•Holds 4 ea. C cells• Plastic case•9" leads$.49 ea. 10/S4.25

EPROM Erasing Lamp

• Erases 2708, 2716, 1702A, 5203Q, 5204Q, etc.

• Erases up to A chips within 20 minutes.

• Maintains constant exposure distance of one inch.

• Special conductive foam liner eliminates static build-up.

• Built-in safety lock to prevent UV exposure.

• Compact - only 7-5/8" x 2-7/8" x 2"

• Complete with holding tray for 4 chips.UVS-11EL Replacement Bulb S16.95

UVS-11E $79.95

JOYSTICKS

JS-5K 5K Linear Taper Pots S5.25

JS-100K 100K Linear Taper Pots S4.95

JVC-40 40K (2) Video Controller in case . . , $4.95

6-DigitClock Kit

• Bright .300 hode display

• Uses MM5314

• Switches

■i hold r

ides

y viewable to 20 ft.Simulated walnut case115 VAC operation12 or 24 hr. operation

I componsforme

nts,

JE701 $19.95

JE215 AdjustableDual Power Supply

General Description: The JE215 is a Dual PowerSupply with independent adjustable positive and nega-tive output voltages. A separate adjustment for eachof the supplies provides the user unlimited applicationsfor IC current voltage requirements. The supply canalso 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 ©> 500mA, 10VDC® 750mA,12VDC@500mA, and15VDC@ 175mA.Two, 3-termlnal adj. IC regulatorswith thermal overload protection.Hoatsink regulator coolingLED "on" indicatorPrinted Board Construction120VAC input

• Size: 3-1/2"w X 5-1/16"L x 2"H

JE215Arij.Dua)PowerSupply Kit(asshown). . $24.95

JE200 Reg. Power Supply Kit(5VDC, 1 amp) . . $14.95

JE205 Adapter Brd. (to JE200) i5,±9 & ±12V. $12.95

WJE210 Var. Pwr. Sply. Kit, 5-15VDC.to1.5amp. $19.95

MICROPROCESSOR COMPONENTS

— B080A/8080A SUPPORT DEVICES -

SBQBOA CPU

OP821; 8-Sil Input/Output

DPS2H Priority Interrupt Control

DP8216 al-Dlrecllonal But Driver

DP82Z* Clock General or/Driver

DPS226 Bui Dilvor

DPB228 System Controller/Bus Driver

OP8I38 System Controller

1NS8243 I/O Expander 'or 48 SeriesINSB2S0DP8251DPS253DP67S5

DPS2S9DP6275OPS219DP830JDP830-1DPS 307DPS308DP8310DPB311

Prag. Cornm. I/O (USAP.T)

Ocia

a Peru

6800/6800 SUPPORT DEVICES -

MC68CO MPU

MC6802CP MPU Willi

MC68I0API 12Sx! Stat-

MC6SS1 Peripheral

;j RAM

t [MCW20]

zao (jsociZ80A [7so-i:

CDP1B02

INSS03SN-6

INSB039N-6

lfJSSWON-6

INSSO70N

INSS071N

pias

TMS990CJL

ROM (MC68A30-8)

■Stlte Bui. Trans. (MCIT»)

-MICROPROCESSOR CHIPS

MPU iv/ClochMPU—8-BH (6CPU—Sgl.cnlCPU <X6 9ylo

CPU «/BJSiC

— SHIFT REGISTERS-

Ouai S-Bit Dynamic

Dual 50-Bil Dynamic

Dual iW-SIt Static

Dual Si-Bit Accumulator

256-Bit Dynamic

1024-Bit Dynamlc/Accumuli

500/512-Blt Dynamic

Quad B0-SII Slat

-DATA ACQUISITION-

LM3MZ Constant Curront S.

LM335Z Tempsraturo Transi

LF3SSN JFET Inoul Oo Am

L.F39BIN Simcli 1. Hold Ami

LM399H Tamo.Comp. Prec. I

ADC06WLCN 8-Blt A/D ConverterDAC0806LCN B-BIt D/A Convartei

DATA ACQUISITION (CONTINUED)-

ADC08O9CCN B-BIt A/D Converter (8-Ch. Multl.l

AUC0817CCN B-BIt A/D Converter (16-Ch. Multl.l

DAC10u3L.CN 10-Blt D/A Conv. Micro. Comp. (0.05V.)

DAC1008LCN 10-Blt D/A Conv. Micro. Comp. (0.2OK)

□ AC1020LCN 10-Blt D/A Convartei (0.05V. Lin.)

D/A Converter (0.20V. Lin.)D/A Converter (0.20V. Lin.)

DAC1222LC

CDW51N

AYS1013

1-Chi

?56*4 Slatlt MOS

1024'* Static 4Mm

l .-",0"'. (Mrvi',;-io;;-.;)

MM2I47J5101

4096x1 Fa:256x4 Stat

t 70ni

1MS»I

MM52S2 2Kxl Dynamic

MM52S0/210; 4096x1 Dynamic

MM5290N-2 (41161 16K Dynamic 150ns (UPD41EC-3)MMS293J-3A 8KDyn. 2Mn>( lower i/iolMM5290J)

IIME116-4 16K (2Kx8) Sialic 200ns

82S25 64 Bit RAM (16»40C)

IK Dynamic 16-Oln

JPD414/MK4027rMS1044-45NLrM5*04S

<Stit

4SUI

-PROMS/EPROMS-

16K EPROM (5132K EPROMSK EPROM «S064K EPROM [II

82S23I745188)

B2S11S

B2S 121(715288)

825135

H13(214Q) Character Generator {Upper Cue

2513(3021) Character Generator {Lower Call

NMOS READ ONLY MEMORIES-

MCM66710P 128x9x7 ASCII Shitted w/GreeW

MCM6674QP 128x9x7 Math Symool t Pictures

MCM6B759P 128x9x7 Alpha. Control Cnar. Gen.

MICROPROCESSOR MANUALS-

DS002SCIMDS0026CNINS1771N-1

CQP4Q2MN

- SPECIAL FUNCTION

Dual MOS Clock Driver (5MZ)Dual MOS Clock Driver (5MZ|

Microcontroller with 64-Dlgllana Direct LED DriveMicrocontroller with 64-Dlgll& Direct LED Drive w/N Bus32-5«g.VAC Fluor. Driver (20-1

AY-S-9100AV-5-92O0AV-5-9500A V-5-2376HDD 165-5

74C92J

-TELEPHONE/KEYBOARD CHIPS-

ELECTRONIC TOY MOTORS

£""

";:■;;;■

tomue

V0I,.W

cZ''r-

~W"

—

1 5-6 U

3.0

9.3 00

0 20

6.7ii0

0 90

0.260

1.30

57.0

0D7

.937 O.D. X

1.201 Length MABUCHI RE280 S.99 each

.10/$7.50 . . .100/350.00

JE608 PROGRAMMER

2704/2708 EPROM PROGRAMMER ■ Sft^'

GENERAL APPLICATIONS: ■ ■ ^"

• To progrnm EPROMS 2704 and 2700. ^^B . A^

• Dovolopnionlul systom lor microcompulor circuits ^^H ,- * ^H

• To rotid tho contorts ol n pro piogiammod EPROM ^^B '' ^kW

• To compare EPROM(s) lor canton! dlllerences

• To emulate a programmed EPROM

• To stors program in HAMS tor alterations

• Three separate Display Registers: a LED's tor HexKay onirics, 10 LED's (2:-2'| lor Addreis Rogistor and SLED's for Data Memory Register. The Data MemoryRegister displays (he conlenl ol tho RAMs Irom the EPROM Chip. Development ol microprocessor systems bymeans ol a ribbon cable irom the programmer panel last socket to Ihe EPROM socket on the microprocessorboard. Rapid checking verification ol programmed data changes. User may move data from a master to RAM'sor write into RAM's with keyboard entries. Allows msnual slapping manipulation (up and down) at any addresslocation. Stand-alone EPROM Programmer consisting ol: A 19-key Hexadecimal Keyboard assembly, Program-mer Board asaambly with 4 power supplies snd a LEDfTest Socket Panel Board assembly. The Taet Sockel lazero lorce Insertion type. Power requlrsmente: 115VAC, 60Hi. 0W. Compact desk-lop enclosure: Color-coordlnntod designer a case with light Inn pnnofs nnil molded end plocos In mocha brown. Slzo:3'/. "H < I1"W

• B'V'D. Weight: S lbs.

The JE608 EPROM Prog-emmer is a completely sell-contained unit which is indepandent of computer control and requires noadditional systems (or Kj operations The EPROf.1 can ije programmBd from Ihs HsxadacimBl Keyboard or Irom a pre-programmed EPROM ThsJECOS Programmer can emulate a programmed EPROM by the use of its internal RAM circuits.This will allow the user to lest or pretest a program for a system, prior to programming a chip. Any changes in the program canbe entered directly into ihc memory circuits with the Hexadecimal Keyboard so that rewriting the entire program will not benecessary. Tho JE608 Programmer contains a Programmer/Board w/25 IC'a & includes power supplies of; -EV,+ 5V, + 12V end +26V The Hexadecimal Keyboard and LED/Test Socket Panel board are separate assemblies within the

JE608K Kit $399.95

JE608A Assembled and Tested $499.95

JE608-16K ADAPTER BOARD

GENERAL DESCRIPTION: FOR 2716/2758 EPROMS

The JEBOS-16K Adapter Board allows the JE806 Programmer to be modi'iod lor the additional programming ol tho 2716 end2758 EPROMS. The edastor provides for addinp, an address switch for the 2" bit and also for selecting the proper power endtiming pulses to be eppled to the EPROM. Programming and emulating the 2716 (16KI EPROM is done separately to eachhalf (1024x81 of the EPROM because of the existing BK RAM capacity in the JE608 Programmer.

JE608-16K Adapter Board Kit $29.95

JE608-Upgrade (Send assembled JE608 to factory for adapter installation S99.95

of the JE608-16K Adapter Board Kit)JE60BA-16KMod. Assembled JE608w/Adapter IJE608-16K) Installed $599.95

$10.00 Min. Order - U.S. Funds Only Spec Sheets - 25b!

Calif. Residents Add 6% Sales Tax Send 869! Postage for your

Postage-Add 5%plus$1 Insurance FREE 1982 JAMECO CATALOG

t-t^v IBSBBB? phone

y vja?- X mSmwwm&Cn orders

!c$*?S* I5?'"?r.yy WELCOME

ly>^ %JUES3EI33ER (415)592-809?

MAIL ORDER ELECTRONICS - WORLDWIDE1355 SHOREWAY ROAD, BELMONT, CA 9400210/81 PRICES SUBJECT TO CHANGE

BOOKS

National Semiconductor — Intarall — Intel

30001 National CMOS Data Book *6.95

(&W pages) 74C, CD4O00, and A/D Converters

30002 National Interface Data Book tG.96

(704 pogos) DP, DS8000, OS3500, DS75OO0, etc.

30003 National Linear Data Book S7.96

11376 pagesl LM, LF, ADC, DAC, LH Series

30004 National Series 80 - Board Level Computer 1224 pages) . . M.96

30005 National TTL Logic Data Book S6.9E

1624 pages) 74O0,LS,L,H.S. and DM8000 Se;ies

30006S Buy above IS) 30001,2,3,4,5 ea a eat «4.96/lot

30009 Intersil Dam Book (1074 pages) SG.95

□10400 Intel Component Dota Catalog 410.00

Full data shoots for Intel's products incl. memory devices,

microproc., peripherals 8 indust./mil. products 11328 pages)205610 Intel Peripheral Design Handbook (7.50

Full data sheets, appl. notes for Intel peripheral device

components 1644 pages)

AC and DC Wall Transformers

m

^^^^^Vgm 9'rrei, power lu]iplie) 01

■ / llCippliciinon.

Part No. Input Output Price

AC 250 1 17W60Hz 12 VAC 250mA S3.95

AC 500 117V/60H2 12 VAC 500mA $4.95

AC1000 1 17V/60HZ 12 VAC 1 amp $5.95

AC17O0 1 17V/6DHz 9 VAC 1.7 amp $3.95

DV 9200 1 1 7V/60Hz 9 VDC 200mA $3.25

DC 900 120V/60HZ 9 VDC 500mA S3.95

CONNECTORS

DB25P D-Subminiature Plug $2.95

DB25S D-Subminiature Socket $3.50

D20418-2 ScrewLockHdwr.(2l DB25S/P 2/$.99

DB51225 Cover for DB25P/S $1.75

22/44SE P,C. Edge 122/41 Pinl $2.95

UG88AJ BNC Plug $1.79

UG89/U BNC Jack $3.79

UG175/U UHF Adapter S .49

S0239 UHF Panel Recp $1.29

PL258 UHF Adapter $1.60

PL259 UHF Plug $1.60

UG260/U BNC Plug $1.79

UG1094/U BNC Bulkhead Recp $1.29

TRS-8016K Conversion Kit

Expand your 4K TRS-80 System to 16K.Kit comes complete with:

*8ea. MM5290(UPD416/4116H6KDyn. RamsCNS)

* Documentation for Conversion

TRS-16K2 M50NS $29.95

TRS-16K3 -200NS $24.95

TRS-16K4 "250NS $19.95

JE610 ASCIIEncoded Keyboard Kit

The JE610 ASCII Keyboard Kit can be interfaced intomost any computer system. The kit comes completewith an industrial grade keyboard switch assembly(G2*keys), IC's, sockets, connector, electronic compo-nents and a double-sided printed wiring board. Thekeyboard assumbly requires +5V @> 150mA and -12V@ 10 mA for operation. Features: 60 keys generate the126 characters, upper ana lower case ASCII set. Fullybuffered. Two user-define keys provided for customapplications. Caps lock for upper-case-only alpha charac-ters, Utilizes a 2376 (40-pin) encoder read-only memorychip. Outputs directly compatible with TTL/DTL orMOS logic arrays. Easy Interfacing with a 16-pin dip or18-pin edge connector. Size: 3K"H x 14'/a"W x 8%"D

JE610/DTE-AK ^&^XJ] ...$124.95

■rein i/:+ 62-Key Keyboard, PC Board, a -waneJbblO Kit & Components (no case) $ 79.95

K62 62-Key Keyboard (Keyboard only) . . .$ 34.95

DTE-AK (case only - 3VHxll"Wx8VD)$ 49.95

JE212 - Negative 12VDC Adapter Board KitNE'Wl? for JE610 ASCII KEYBOARD KIT

-,ovides-12VDC from incoming 5VDC . .$9.95

JE600Hexadecimal Encoder Kit

FULL 8-BITLATCHED OUTPUT19-KEY KEYBOARD

fo

i seque

or 8-bit memory circuits. Thrtvided for user operations wi:output available. The outputs iwith 9 LED readouts. Also inclFeature

al key entries[croprocessoradditional keys are pro-i one having a bistablee latched and monitoredded Is a key entry strobe.

latched output foruse. Three user-define keys with one being bistableoperation. Debounce circuit provided for all 19 keys.9 LED readouts to verify entries. Easy interfacing withstandard 16-pin IC connector. Only +5VDC requiredfor operation. Size: 3'/i"H x 8'/*"W x 8J/«"D(After assembledis pictured above) ■ ■

JE600/DTE-HK

$99.95

K19 19-Key Keyboard [Keyboard only) .... $14.95DTE-HK (case only —3V;"Hx8V."wx8*."D) $44.95>

Circle 189 on inquiry card.

BYTE October 1981

517

v, +

NT

S-IOOCPU

CPU* •OODBOUT

I MHZ Z80 CPU 24 Bit Addressing

UnKit $225.00

AST. $198.00

CSC 3-6 MHZ $375.00

8.BT180UGBT 160ASBT 180CDUAL PROCESSOR SOW BOSS ■ OODBOUT

5 MHZ Provides true 16 Bit Power with a standard

^0 MC

l"9. 125.00 J*n

9.00 r

SbltS-100 bus

QBT1612U 1/nK/f $295.00

QBT1612A A&T $399.00

QBT1612C CSC $498.00

BOARD WITH BOW OMLT

QBT 161U UnKIt $235.00

QBT161A AST $305.00

QBT161C CSC $399.00

mo zao cpu-ca. coup, syst.

214 MHZ Z80A CPU with RS-232C Serial I/O Portcomplete with Monitor PROM lor 2422 Disk ControllerCCS2B10 AST $280.00

cn no cro ■ bail

2/4 MHZ will accept 2716, or 2732, or RAMRUN/STOP and single step switches

SSMCB2K Kit $260.00

SSMCB2A AST $310.00

SSMZ80M

$89.00

$183.00$225.00

$59.00

SSM Zao MonitorCBIASOSOCPU

8080CPU, 1K RAM, Holds 1 2708,1 8 Bit parallel input port.

SSMCB1A Kit

SSMCB1A AST

SSMS080M SM 8080 Monitor

S-IOORAM

ME STATIC BAM ■ OODBOUT

RAM 17, 10 MHZ, 2 Watt, DMA Compatable

QBT-175A48 AST 48K $950.00

QBT-175C48 CSC 48K $1050.00

QBT-175A64 AST 64K $900.00

QBT-175C64 CSC 64K $1395.00

MK DYNAMIC BAM - CO

4 MHZ, on board refresh, DMA compatable,

24 bit address.

AST $599.00

raw STATIC BAM • OODBOUT

RAM 20 10 MHZ, 4K byte block disable,

available 16, 24, or 32K

AST 16K $319.00

CSC 16K $418.00

AST 24K $449.00

CSC 24K $539.00

AST 32K $449.00

CSC 32K $720.00

32K STATIC BAM ■ CCS

4 MHZ, Bank select, 8116 bit data

CCS-2032 AST 32K $599.00

16K STATIC RAM - OODBOUT

RAM 14, 10 MHZ, 24 bit addressing

QBT-143A AST 16K $169.00

QBT-143C CSC 16K $399.00

14K STATIC BAM - CCS4 MHZ, 8/16 bit data, bank select

CCS-2116A AST 16K $299.00

SK STATIC BAM - OODBOUT

Econoram II 2MHZ, 8K, No doubt, the most

popular S-1O0 RAM ever built.

QBT-114U UnKIt 8K $99.95

CCS-2M5A

QBT-184A18GBT-1S4C16QBT-164A24QBT-164C24QBT-164A32QBT-164C32

S-IOOROM

FBI PBOM nOOBAMMBB - SSM

'programs 2708 or 27i6's, operates•a 4K/8K EPROM board as well.

SSM-PB1K Kit $154.95

SSM-PB1A A&T $219.00

ICOMOBOM 270* - OODBOUT

16K x 8 EPROM Board using 2708, Power onlump to any 256 byte

125U UnKIt $85.00

QBT125A AST $120.00

QBT125C CSC $175.00

S-lOO DISK CONTROLLERSDISK I - OODBOUT

DMA, Soil Sector, Controls 8" or S'A",single or double density

QBT171A AST $450.00

QBT171C CSC $555.00

QBT CPM80 CP/M 2.2 lor Z80/8085 with

Manuals S BIOS 8" S. O. disk $175.00QBT CPM86 CP/M for 8086 with manuals

SBIOS8"S/Ddisk $300.00

2422A - CA. COMF. STST.

I/O Mapped, controls 8" or 5V<", single

or double density

CCS-2422 AST with CPM 2.2 8" S.D.... $365.00

DISK JOCKEY I - MORROW

. kA Single density disk controller with

JN serial I/O, controls 8"

MDSDJ1108 AST $219.00

DISK JOCKET 2D - MOBBOWI/O Mapped, controls 8", single ordouble density, serial I/ODSDJ2208 AST with CP/M 2.2 $375.00

DISK DRIVES

SOn-SHUOABT

Single sided double density most popular 8" drive

SHU80IR $425.00 ea. or 2 or more $395.00

SHUSA80IRM Manual lor 80IR drives $10.00

DM-•BUI

Data track 8 double sided, double density

QME-DT8 $625.00 ea. or 2 or more $600.00

ea.

DISK CABINETSv-ioo - TOTA

Dual 8" drive cabinet with power supply.Rack or Desk Mount

V1S-V100 $395.00

SINQLE 8" • Q.T.Single 8" cabinet with power supply

QTC-DDC8 $195.00

S" CABIMBTS - VISTA

VIS-9B01 Single 5" with P.S $75.00

VIS-9802 Dual 5" With P.S $95.00

S-lOO DISK SUBSYSTEMSDISCUS StNOLI BOSS MOBBOW

8" DBL Density drives with cabinet, power supplycontroller, with CP/M 2.2 and Microsoft Basic

MDSF1218 Single Drive System $950.00

MDSF1228 Dual Drive System $1598.00

DISCUS DOUBLE HDID - MOBBOW

8" DBL Density/sided drives with cabinet Power

supply controller, with CP/M 2.2 and Microsoft Basic

MDSF2218 Single Drive System $1250.00

MDSF2228 Dual Drive System $2195.00

26MB HARD DISK - MORROW

Special purchase, limited stock ■ 26MB formatted harddisk complete with cabinet, P.S., Controller, CPM 2.2

and Microsoft BasicMDS-M26S 26 MB Subsystem List $4495.00

SALE* $3495.00 •

SAVE SLOOO.OO

FLASH!!

Purchase the GBT-1612A(CPU 8085-8088) and GBT-175A(64 RAM 17 64K) togetherfor $1195.00

See page 203 for further details.Order pdp spec n

*$$&>»

MOO I/O BOARDS

SYSTEM SUFFOBT I ■ OODBOUT

Serial port (software prog baud), 4K EPROM or

RA M provision, 15 levels of Interrupt, real time clock,

optional math processor

QBT-162U UnKIt $295.001

GBT-162A AST $360,001

GBT162C CSC $480,001

GBT 9512 Math Ohio $195.001

MFX CHANNEL BOARD - OODBOUT

I/O Multiplexer, using 8085A-2 cpu on board

GBT-166AQBT-166C

GBT-133AGBT-133C

AST.CSC.

$450,001

$550.001

DREBrACKB I ■ OODBOUT

Two Serial I/O

AST $219,001

CSC $296.001

DfTERTACEB n - OODBOUT

Three parallel, one serial I/O board

QBT-150A AST $219,001

QBT-150C CSC $298.00|

INTERFACED III - OODBOUT

Eight channel multi-use serial I/O board

GBT1748A A&T $629.00 I

GBT1748C CSC $ 775.00 |

INTERFACES 3 WITH 5 SERIAL PORTS

GBT1745A AST $559.00 I

GBT1745C CSC $629.001

MULTI I/O - MOBBOW DEMONS

Three Serial, Two parallel

MDSMB3200 AST

SWRCIIBOABDMOBROW DESKMS

Two serial I/O, four parallel I/O,one status port, one strobe port

$309,001

MDSSB2411

AST.

$239,001

SSMI04KSSM 104 A

SSMSBIKSSMSBIASSMSBIS

I/04-SSM

Two serial I/O, two parallel I/O

Kit $210,001

AST $260.001

Music synthesizer board

Kit $249,001

AST $310.001

Software $ 25.001

GBT-144U

GBT-144 AGBT-2D

S-lOO VIDEO BOARDSSPECTRUM • OODBOUT

Color Graphics board with Parallel I/O.

UnKit.

AST

Sublogic Software.

$299,001

$349.001$ 35.001

VB-31

80 x 24 or 48 character video display Memory Mapped,Parallel Keyboard port

SSM-VB3K24 Kit 80x24 $349.001

SSM-VB3A24 AST 80x24 V29.001

SSM-VB3UP upgrade Kit.ss,4» $ 30.00]

VU-tuf

I/O Mapped Video Board, with Parallel Keyboard port.

64x16

SSM-VB2K Kit $169,001

SSM-VB2A A&T $229.00|

VMC-SSM

Memory Mapped Video Board 64x16 character display Ior 64x16 graphics dislplay

SSM-VBICK Kit S16S.0O I

SSM-VBICA A&T S220.00|

S-lOO MOTHERBOARDS

MOTHERBOARD ■ OODBOUT

Active termination. 6-12-20 slot

QBT-153U Unkit 6 slot $ 89.001

QBT-153A AST 6 Slot $119,001

QBT-154U Unkit 12 slot $129,001

QBT-154A A&T 12 slot $149.00 I

QBT-15SU Unkit 20 slot $174,001

QBT-155A A&T 20 slot $189.00 |

S-IOO MISC

CK017 ACTIVE TERMJHATOR-OODBOUT

QBT-108U Kit $

2S20-CCS

Extender/terminator, Active and/or passive

CCS2520AK Kit $ 59.00 |

EXTENDER/ LOOIC PROSE-MULLEN

MUL-CK004

SSM-OB1KSSM-OB1A

LSI

PRIORITY rONE~l ELECTRONICS

9161-B DEERLNG AVE. • CHATSWORTH, CA 91311

Kit.OBI VECTOR JUMP - SSI

with prototyping area

Kit

A&T

$ 59.00

85.009000 1

<*&»&,*

***^

Tonus. USj VISA. MC BAC, Chock Monoy Older, US. Funds Only. CA residents add 6% Sales Tax. MINIMUM PREPAID ORDER S15.CO. Include MINIMUM SHIPPING 8t HANDLING cS250 tor the (tat 3 lbs., plus 25< tor oach additional pound Orders over 50 lbs. sont trelaht, collect. Just In case.please Include your phone no. Prices subject to change withoutnotice. We will do our best to maintain prices thru October. 1981. SOCKET and CONNECTOR prices based on GOLD, not exceeding S700.00 per oz.

Sail Prices Valid only H VCt/ mention publication and month Credit Cardlordor«_wfflbechcjaedapproprlate&eiaht.

Circle 305 on inquiry card.

BBBl BBl i'

STAR MODEM

FROM

LIVERMORE

LIST PRICE

0 to 300 baud data rate. Compatible Ipiyy.UU

with Bell 103 and 113. Answer/ SALE PRICEOriginate. Full/Half Duplex. Special Ql^O ^\^\self test features. V L&T,\J\J

RS232 and "D" SUB-MINIATURECONNECTORS

fa

^ifliWi%\ ^S

L^mLJ

mm^7

P= Plug, MaleType - S= Socket, Female Type - C= Cover, Hood

PART NO.

CND-DE9PCND-DE9S

CND-DE9CCND-DA15PCND-DA15SCND-DA15C

CND-DB2SPCND-DB2SS

CND-DB51212

CND-P25H

CND-DB5122E

CND-DC37P

CND-DC37SCND-DC37CCND-DD50PCND-DBSOSCND-DD50CCND-D2041B

CND-RS2328F

CND-S730360

DESCRIPTION

9 pin male9 pin icmole9 pin coverIS pin male15 pin female15 pin cover

25 pin male25 pin female

1 pc. grey hood

2 pc. grey hood2 pc. black hood

37 pin male

37 pin female

37 pin cover

50 pin male

50 pin female

50 pin cover

Hardware set 2 pr.

RS232, DB25P, EIA

Class 1 cable 8 con. 8 ft.

Cent. 700 Series

Printer connector

1-9

S 2.10

$ 2.70

$ 1.50

$ 2.75

$ 3.95

$ 1.50

$ 3.50

$ 4.60

$ 1.60

$ 1.50

$ 1.90

$ 5.80

$ 8.70

$ 1.80

$ 1.75

$11.65

$ 2.00

$ 1.00

PRICE10-24$ 1.90$ 2.40$ 1.25$ 2.45$ 3.60$ 1.30

S 3.25

$ 4.35

$ 1.45

$ 1.25

S 1.65

$ 5.10

S 7.70

S 1.55

$ 7.75$10.25

$ 1.80

$ .80

25-99

i 1.70

$ 2.10

S 1.10

$ 2.15

S 3.20

$ i.io

$ 3.00

S 4.20

$ 1.30

$ 1.10

$ 1.45

$ 4.45

$ 6.70

$ 1.30

$ 6.70

$ 8.90

$ 1.60

$ .70

$19.95 $17.95 $15.95$ 9.00 $ 7.50 $ 6.00

MICROCOMPUTER PRODUCTS

PART NO.

PRICE

2016P3

2114N3L

5257N3L

2732

2716

2708

8/S100.008/S28.008/S50.00

8/S120.008/$50.008/S32.00

6502 SERIES

PART NO. PRICE

8080 SERIES

PART NO. PRICE

INS 8080A

$5.50

INS 8085A

$19.95

DP8212N

$2.95

DP8214N

$5.25

DP8216N

$2.95

DP8224N

$3.25

DP8224-4N

$9.95

DP8226N

$3.50

DP8228N

$5.55

DP8238N

$5.55

INS8250N

$15.00

INS8251N

$7.50

INS82S3N

$17.95

INS8255N

$6.80

INS8257N

$16.45

INS8259N

$18.00

INS8275N

$59.95

INS8279N

$49.95

Z80 SERIES

Z80A

$14.95

Z8OAF10

$14.95

Z80ACTC

$13.95

Z80ADMA

$45.00

Z80ASItlO

$59.95

Z80ASr01

$59.95

Z80AS102

$59.95

6502

6502A

6520

6522

6530-002

6530-003

6530-004

6530-005

6532M

6551M

$12.95$18.95$8.95$10.95$21.95$21.95$21.95$21.95$21.95$21.95

6800 SERIES

PART NO. PRICE

MCS800P

MC6802P

MC6808P

MC6809P

MC6821P

MC6828P

MC6840P

MC6845P

MC6847P

MC6850P

MC6852P

MC6854P

MC6860P

MC6662P

MC6875L

MC66710P

MC66750P

UARTS

PART NO

$11.95$17.95

$9.95$34.95

$5.95$14.95$14.95$31.00$14.95

$5.41

$5.79$24.95$10.89$12.00

$7.40$12.50$12.50

PRICE

FLOPPY DISCCONTROLLER

AY51013A

TR1602B

TR1863

IM6402

$5.95$5.95$6.95$7.95

FD1771B-01FD1791B-01

$24.95$44.95

VSEM1

S-100 "ANY DIP" has full power andground planes back to back. Boardsaccommodates .3. .4. .6, .9" Dips.

1-4 5-9 10-24

$24.67 S22.34 $20.02

APPLE PLUGBOARDVector 4509 Peripheral InterfacePlugboard for construction of customcircuits. Plug compatible with AppleII, Commodore PET and Super Kimmicrocomputers. VCT-4609

1-4 5-9 10-24

$20.74 $18.79 $16.84

SHEET!

Universal Microcomputer/

processor plugboard use withS-100 bus. Complete with heatsink & hardware. 53" x 10" x1/16".

1-4 5-9 10-24

$22.48 $20.37 $18.26

VCT-8801-1Same as 8800V except plain, lesspower buses & heat sink.

1-4 5-9 10-24

$15.67 $14.24 $12.82

Plugboards

from

^ EUrCTKOMCS ^

CompuPro'

10 MHZ 16K A&TSTATIC S-100 RAM

Lists349.oo $169.00 Ea

I3/S450.00

• Operates up to 10 MHZ (90 ns RAM Chips)

• Assembled & Tested • Meets or exceedsall IEEE 696/S-100 specifications (includingtiming). • Fully static design eliminates thetiming problems associated with dynamicmemories. • Switch selectable choice of 24address lines conforming to the IEEE696/S-100 extended addressingspecifications, or 16 address lines as usedin older S-100 systems. • Ideal for multi-userinstallations. • Board is addressable as one16K x 8 block on any 4K boundary. • Switchselectable PHANTOM disable and writeprotect. • + 5 Volt operation (requires noother supply voltages). • Low poweroperation (900 mA typical, 1200 mAmaximum).' 1 year Factory Warranty.

VCT-3682 9.6" x 4.5"

$13.63

VCT-3862J6.5"x4.5"

$11.04

Hi-Density Dual-ln-Ltne Plug-board for Wire Wrap with Power& Grd. Bus Epoxy Glass 1/16"44 pin con.spaced.156

VCT3677 9.6"x4.5"

¥CT-3667 96"x4.5"

$13.33

VCT-3677-2 6.5"x4.5"

$10.68

Gen. Purpose D.I.P. Boards withBus Pattern for Solder or WireWrap. Epoxy Glass 1/16" 44 pincon.spaced .156

VCT-3662 6.5"x4.5"

$8.69

VCT-3662-2 9.6" x 4.5"

$10.85

P pattern plugboards for IC's Ex-poxy Glass 1/16" 44 pin con.spaced.156

VCT-3690-12 $26.64

CARD EXTENDER

Card Extender has 100 contacts50 per side on .125 centers-Attached connector-is compati-ble with S-100 Bus Systems.VCT-3690 6.5" 22/44 pin.156 ctn. Extenders ...$15.86

1/16

j/eetot

BOARD

.042 diaholes on0.1 spacing for IC's

Phenolic

PART NO. SIZE

VCT-64P44-X 4.5" x 6.5"

VCT-169P44-X 4.7" x 17"

Epoxy Glass

VCT-64P44 4 5" x 6.5"

VCT-84P44 4.5" x 8.5'

VCT-169P44 4.5" x 17"

VCT-169P48 8.5" x 17"

PRICE1-9 10-19$1.56 $1.40

$3.69 $3.32

TRS-80/APPLE

MEMORY EXPANSION KITS4116'sRAMS

from Leading Manufacturers

(16Kxl 200ns)

8 for $20.00

Add $3.00 for programming Jumpersfor TRS-80 Keybaord

POWERLINEINSOLATOR

GOF-IBAHW3

SH. WT. 3 lbs.

List Price $59"Sale Price$29.00

A MUST FOREVERY OFFICEWITH DATAPROCESSINGEQUIPMENT

SEND $r°

for 60 Page

CATALOG

6 OUTLET

MULTI USE

CORD REEL

tSH.WT. 5 LBS.rG0F-CRl 22 It. Cord $24.95GOF-CR50 50 ft. Cord S49.95

SPECIAL PURCHASE

j^GOLD

<vJ?F)l6FINLOWVf]PROFILE LC.C-35BOOKETS

TIG-16LPPkg.olioo $16.00

TIG-16LPPkg.ofiooo $120.00

OEMS Stock up at this LOW PRICE

1M-10A List $104.95SPECIAL$60.95 with tubePerfectly balanced fluores-cent lighting with precisionmagnifier lens. Toughthermoplastic shade. Easylens removal. New wire clipdesign permits easy instal-lation and removal offlourescent tube. Comes

LEOU

with plastic shield to pro-tect tube from soiling anddamage.

Colors: Gray, Black, andChocolate Brown. Comeswith one 22 watt T-9 Circlinefluorescent tube, 3 diopterlens. 10 lbs.

9*

PRIORITY fONE I ELECTRONICS

9161-B DEER1NG AVE. • CHATSWORTR CA 91311OKDIK TOLL FRH (SOO) 423-5922 CA, AK, HI CALL (213) 709-5464~EDA

Terms. US., VISA. MC BAC, Check Money Order, US. Funds Only. CA residents add 6% Sales Tax. MINIMUM PREPAID OKDEK ST5.00.Include MINIMUM SHIPPING 8c HANDLING of $250 for the first 3 lbs, plus 25C lor each additional pound Orders over 50 lbs. sentheight, collect. Just In case.please Include your phone no. Prices subject to change without notice. We will do our best to main-tain prices thru October 1981. SOCKET and CONNECTOR prices based on GOLD, not exceeding S700.00 per oz.

Sales Prices Valid only 11 TOP mention publication and month. Credit Card orders win be charged appropriate freight.

Circle 305 on inquiry card.

PRIORITY ONE ELECTRONICS

ONE

tut!

^ ,™ r iv

MMHI : :J

m r t.

■?»*"* "Siteff*'

STfi IfffiPttftfl

fffffff$ »»$$$«§ M'9***'r'«9*««9« fffffflfft f ■?-?'» Jf

Hl^^lfil

Batagg

PRICE $1095.00 SAVING: $429.00

SOURCE: PRIORITY 1 ELECTRONICS Manufacturer: COMPUPRO From GODBOUT (Of Course)

CPU-Z

The CPU Z board is an 8 bit workhorse that not only includes all standardZ80A* features, but also has the necessary options to ensure backwardcompatibility with most older S-100 mainframes. This board optionallyruns at slower clock speeds if needed, generates M WRITE for systemsrequiring this signal, and even includes a plug that accepts the connectorfrom an IMSAI type front panel. Other features include:

• Full compliance with all IEEE 696/S-100 specifications(including timing specifications).

• Downward compatible with the vast library of 8080 software.

• 24 bit addressing allows access to 16 megabytes of memory.

• Ideal for multi-user installations.

• Designed for high speed operation that greatly increases systemthroughput (switch selectable choice of 2 or 4 MHz operation for*i»»kliiVTaititf boards; choice of 3 or 6 M Hz lor boards quali-fied under the CtC high-reliability program).

• Provision for adding, up to 8 kilobytes of on-board memory(2716/2732 EPROMs or 6116 RAMs-not included with board).

• On-boara memory sockets may be disabled under software controlto allow overlapping RAM.

• On-board fully maskable vectored interrupts for interrupt drivensystems.

• Power-on clear (POC) generates SLAVE CLR- and pRESET*.

• Selectable automatic wait state insertion for servicing M1"instructions—MRQ'—I/ORQ"— or the on-board memory (may beinserted in any or all of the above).

• Automatic jump upon Reset or power-on to any 256 byte boundary.

• Non-maskable interrupt on bus pin 12, as per IEEE 696 specs.This powerful and flexible CPU board provides the sophisticated

operation required by today's S-100 computers, while allowing forcomplete compatibility with older systems as well. But perhaps best ofall, CPU Z is cost-competitive with boards that do considerablyless. When you need a powerful 8 bit CPU board that isat home with thelatest (as well as some of the earliest) S-100 systems. GPU Z is theanswer.

DISK1

HIGH PERFORMANCE

FLOPPY DISK CONTROLLER

Finally, a floppy disk controller worthy of bearing the Compu Pro nameis now available for integration into your S-100 system. The DISK 1floppy controller incorporates numerous features that were previouslyunavailable onaDMAfloppy disk controller board. DISK 1 fully complieswith the IEEE 696 bus standard, INCLUDING DMA ARBITRATION!

• Third generation INTEL 8272/NEC 765A LSI floppy disk controller.

• High speed cycle stealing DMA interface for processor independentdata transfer between system memory and flexible disk.

• Handles up to four 8 or 5.25 inch floppy disk drives.

• Single or double density/single or double sided capability.

• Supports IBM 3740 soft sectored formats

• 24 bit DM A addressing with data transfer across 64 K boundaries fordata transfer throughout the 16Mbyte memory map.

• I/O mapped interface allows contiguous system memory. (DISK 1occupies no memory space)

• On board Phantom boot EPROM for automatic startup.

• On board serial port lor initial system startup

• Board compatible with MP/M. OASIS, CP/M-80 and CP/M-86.

• CP/M-80 and CP/M-86 available for DISK 1.

• CPU speed independent data transfer lor operation up to 10MHz.

• Fully arbitrated DMA interface as per IEEE 696 for allowing multipleDMA devices without conflict

• May be interrupt driven for multi-user environments.

• Up to 600K bytes per side (8 inch drive) for an on-line total of up to4.BM bytes (4 drives - double sided-double density).

All these features should convince you that DISK 1 is the only choicewhen creating the highest performance S-100 disk system available -

day and in the future. The DISK 1 provides the advanced capabilitiesrequired by high performance single and multi-user microcomputersystems. Whether designing a new disk system or upgrading a lowerperformance disk system, DISK 1 yields the best cosfperformance ratioavailable today.

RAM 20 10 MHz32 K STATIC RAM

You don't have to pay a lot of money for a lot of memory: despite thesurprisingly low price, RAM 20 includes all the features that you wouldexpect in a memory board where cost is no object. Available in 16K, 24 K,and 32K configurations, RAM 20 includes the most sought afterfeatures for any quality memory board:

• Meets or exceed all IEEE 696/S-100 specifications (includingtiming)

• Fully static design eliminates the timing problems associated withdynamic memories.

• Switch-selectable choice of 24 address lines conforming to the IEEE696/S-100 extended addressing (16 megabyte) specification, or16 address lines as used in bank select and older S-100 systems,memory addressing (including Cromemco, Alpha Micro, and others)as well as newer systems conforming to the IEEE 696 extendedaddressing protocol.

addressing protocol.

• Ideal lor multi-user installations

• CSC and Assembled/Tested boards are deisgned for CPU speeds upto 10 MHz.

• Board is addressable as one 32K x 8 block on any 4K boundary.

• Each 4K row can be individually disabled via DIP switch.

• Switch selectable PHANTOM disable and write protect.

• +5 Volt operation (required no other supply voltages).

• Thorough bypassing of all supply lines.

• Careful thermal design to minimize heat build-up.

• Heavy power and ground traces.

• Low power operation (1200 mA typical, 1500 mA maximum).

RAM 20 delivers Ihe high-density memory needed by every S-100computer system - in a cost-effective and exceptionally well-designedpackage. Whether for 24 bit address systems or bank select systems.

RAM 20 provides economical and cost-effective mass storage.

ANOTHER PRIORITY 1 EXCLUSIVE!

We went to GODBOUT and made a special buy on the nucleous of the best S-100 Z80A* systems ever.

LOOK AT WHAT YOU GET:

1 GBT160A 2/4 MHz Z80 CPU $295.00

1 GBT164A32 32K 10MHz Static Ram $559.00

1 GBT171A DMA Disk Controllers $495.00

1 GBTCPM80 CP/M 2.2 $175.00

IT ALL ADDS UP TO $1524.00

TOTAL PACKAGE PRICE $1095.00

You Save $429.00

ORDER PART NO. PDBGBTSG

Now it gets even better, add 2 Shugart 801R disk drive cabinets with powersupply, data cable & OEM manual.

IT ALL ADDS UP TO $2854.00

TOTAL PACKAGE PRICE $2250.00You Save $604.00

ORDER PART NO. PDBGBTSH

Shipped Freight Collect

TAKE A DEEP BREATH!SIT DOWN!

We made a special buy on a quantity of REMEX 4000 Double Density, Double

Sided 8" disk drives. Install those in the VISTA cabinet in place of the Shugarts

and you will have a system that you never dreamed possible.

PDBGBT Adds Up to $3254.00

TOTAL PACKAGE PRICE $2450.00

You Save $854.00

That's Right! For only $200 more you can have double sided drives, DOUBLE

THE CAPACITY! DOUBLE THE SPEED: 3ms!!lBecause of the limited quantities and anticipated high demand for thesesystems, we recommend that you call and confirm the availability of the systemyou desire.

o o o o a o i o o o o I i o a o o o o o o o o a a o o o o o o a o o o « o o ,o o

Need A Mainframe For Your System?

s

Deduct 10% from our already discounted £prices on GODBOUT & TEI. Mainframes if »ordered with any of these specials■tttrvrririns-inrt-rrirvt-tnn»iTtTrrersrrvvri'rvvr

Circle 306 on inquiry card.

PRIORITY ONE ELECTRONICS

WHY WAIT ANY LONGER???

SUPERSIXTEEN

IS HERE TODAY!!!!

Look What $3495.00 Will Buy!

HERE'S WHAT EACH PACKAGE INCLUDES:Dual Processor Board. With this high speed board(5 MHz operation), you have the capability to use thevast library of 8 bit software available today, as wellas the enhanced 16 bit software being developed atmajor software houses for tomorrow's demandingapplications.

Disk 1 DMA Floppy Disk Controller. This is theproduct that started the trend to high speed, DMAdisk controllers. For maximum flexibility, it handlesup to tour 8" or 5.25" floppy disk drives, single ordouble-sided.single or double density (soft sectored).System Support 1. All the most popular "extras"are on this one board: battery operated clock/-calendar; RS-232 serial port; battery backupRAM, math processor, and ROM options; tripleinterval timers; dual interrupt controllers; power failinterrupt; and more.

Interfacer 1. Two RS-232 serial ports, with fullhandshaking and independently selectable Baudrates up to 19.2 KBaud, connect to the serialperipherals (printer, terminal) of your choice.128 K of Static RAM. The best components deservethe best memory, which is why 128 K of our famoushigh speed(10MHz)/low power ram comes standardwith every SuperSixteen package.

CP/M*-2.Z. The most popular 8 bit operating

system, ready to load and go.

CP/M*-86. Rady to load and go for 16 bit operation.

Cables and Documentation. Each package in-cludes three interfacer cables, one disk I/O cable,complete documentation for all hardware, andmanuals for both CP/M* operating systems.Now to the best part of all. If purchased separately,these quality components would list for $4,344. ButSuperSixteen's low package price is anamazing $3,495,

YOU SAVE $849.00

(For boardsqualified under: the Certified System Componenthigh-reliability program - with extended 2 yearwarranty, 200 hour burn-in, and 6 MHz processors -add $600 to the package price. StandardSuperSixteen packages come with usual 1 yearlimited warranty.)

PDGBTSJ SuperSixteen A&T $3495.00

PDBGBTSK SuperSixteen CSC $4095.00

Sh. Wt. 15 lbs.

SAVE EVEN MORE, when you add 2 Shugart 801Rdisk drives, and a dual Vista Cabinet with PowerSupply and Shugart OEM Manual.PDBGBTSL $4650.00

PDBGBTSM With CSC Systems $5250.00

YOU SAVE $1024.00

Shipped Freight Collect

*CP/M is a registered trademark of Digital Research.

\jii

From the power supply through the sturdy chassis, TEI constructs andassembles each mainframe with great care. Every TEI mainframeutilizes a constant voltage transformer (CVT) which delivers cleanregulated power at the proper level, reducing the heat in the computercards. The output voltage on the transformer remains nearly even withthe input voltage varying from approximately 85V to 140V. This meansthe mainframe will never notice voltage variations or even a brownout. Italso provides 100 dB noise erjection to protect the computer fromvoltage spikes and line noise.

No need for a dedicated line or expensive noise fillers. TEI was the firstmanufacturer to offer the CVT in its complete computer product line andis still on of few manufacturers to offer trie CVT as standard eguipment.

TEI22 slot and 12 slot mainframes offer a S-100 motherboard which isgrounded, shielded and actively terminated for high speed operation nowor for later upgrading. Each mainframe is shipped completely assem-bled, tested and burned in, with fan, washable filter, all connectors andcard guides. Rackmount models are available in both 22 and 12 slotmainframes. The combination of the lowest noise bus, a regulated CVTpower system and a rugged chassis produces a mainframe withoutequal.

S-100 MAINFRAMES

LIST

OUR

PRICE

PRICE

TEIMCS 112 12 Slot Desk

$685.00

$015.00

TEIMCS 122 22 Slot Desk

$845.00

$760.00

TEIRM 12 12 Slot Rackmount

$800.00

$720.00

TEIRN1 22 22 Slot Rackmount

$945.00

$850.00

Shipping Weight: On 12 Slot Mainframes 35 lbs.

On 22 Slot Mainframes 50 lbs.

12 slot; + 8V <a 17A ± 16V 9 2A: 35 lbs

22 slot; + 8V @ 30A ± 16V @ 4A: 50 lbs

Shipping Weight: On 12 Slot Mainframes 40 lbs.

On 22 Slot Mainframes 55 lbs.

S-100 MAINFRAME WITH 12 SLOT

MOTHERBOARD AND CUTOUTS FOR

3 5W' FLOPPY DISK DRIVES

LIST OUR

PRICE PRICE

TEITF12 12 Slot Desk $695.00 $625.00

TEIRF12 12 Slot Rackmount $795.00 $715.00

DUAL 8" DISK DRIVE CHASSIS

For Shugart 800/801R with internal power cables provided.

LIST OUR

PRICE PRICE

TEIDFDO Desk Top $535.00 $485.00

TE1RFD0 Rack Mount $725.00 $670.00

•Priority 1 Electronics is a master distributor for T.E.I. Dealers 8.OEM's. Call for quantity pricing.

PRIORITY ONE ELECTRONICS

9161 PEERING AVE. . CHATSWORTH, CA 91311ORDER TOLL FREE (800) 423-5922 CA, AK, HI CALL (213) 709-5464

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 25K for each additional pound. Orders over 50 lbs. sent freightcollect. Just incase, please include you phone no. Prices subject to change without notice. Credit Card orders will be charged appropriate freightPrices subject to change without notice. We will do our best to maintain prices through October, 1981.

LIST PRICE: $2495.00

SPECIAL PRICE$1595.00

ONi

malibu

Electronics Corporation

10x9 DOT MATRIX WITH TRUE DECENDERSALPHANUMERICS/GRAPHICS PRINTER

We were able to acquire this most popular printer when Malibu replacedthis model with a new version. These printers, still in the factory sealedcontainers are available at tremendous savings on a first-come, first-served basis.

SPECIFICATIONS: 165 CPS • 132 charper line • Graphics res 60 HX72V • Adj. tractor feed 3" to 16" width • 10 character per inch or 5expanded lines per inch 2, 3, 4, 5, 6, 8, 10 for alpha numerics 12 forgraphics • paper load front or bottom • complete self test mode •self-contained intelligent controller card handles both serial and parallelinterfaces • audible signaling • out of paper detection • bidirec-tional w/logic seeking.

MALI BUI 65 Serial/Parallel Interface $1595.00

MAUBU1652 Parallel only Interlace $1450.00Shipped Freight Collect

®lj)G>B(»

^ EtECTRONfCS ^

Now...a place to put this CompuPro or other S-100 boards. The enclosures areavailable in either desk top or rack mount (including slides) and both have thefollowing features:Enclosure

• Quiet fan provides for cool system operation.

• Two switched convenience outlets on the rear.

• Line filter for electrical noise suppression.

• dCircuit breaker for safe operation.

• Ughted RESET BUTTON FOR "POWER ON" indication.

• Punchouts on rear for 12 DB-25 connectors.

• Punchouts on rear for 2 DD-50 connectors.

• Positive pressurized for ease of filtration.

• Provisions for mounting a front panel.

• Physically 18.5" deep, 7" high, 17" wide (rack front panel 19" wide).Motherboard

• Actively terminated at both ends of motherboard.

• Ground shield between every signal trace.

• Convenient power plug for connecting all D.C. power.

• RESET connector provided

• Front panel provisions on the 20 slot version.

• Extra power connectors for more efficient power distribution 12 slot and20 slot versions.

• Thorough by passing of all power lines.Power Supply

• Twenty-five Amps at 8.0 volts D.C.

• Three Amps each at + 16 and -16 volts D.C.

• Outputs vary less than 5% over input range of 100 AC to 130 VAC.

• Constant voltage transformer.

• All outputs fused.

With all the features listed above, the individual assembling a system can besure that he will have the very best foundation possible for an IEEE 696-8-100system that will give years of reliable service. And because of the constantvoltage transformer the power outputs can be kept near the minimum requiredwith no wary about system failure. This allows the system to run cooler, andthe requlators to stay cooler also.

UST OUR

PRICE PRICE

GBTENC20RM 20 Slot Rack Mount $895.00 $825.00GBTENC20DK 20 Slot Desk Top $825.00 $700.00

Shipping Weight 55 lbs.

Circle 306 on inquiry card.

16K Memory

ALL MERCHANDISE 100% GUARANTEED!

4116-200ns

8/17.50

CALL US FOR VOLUME QUOTES

LS SERIES

8200

MPU'S

74LSOO

74LS01

74LS02

74LS03

74LS04

74LS05

74LS0B

74LS09

74LS10

74LS11

74LS12

74LS13

74LS14

74LS15

74LS20

74LS21

74LS22

74LS26

74LS27

74LS28

74LS30

74LS32

74LS33

74LS37

74LS38

74LS40

74LS42

74LS47

74LS48

74LS49

74LS51

74LS54

74LS55

74LS63

74LS73

74LS74

74LS75

74LS76

74LS78

74LS83

74LS85

74LS86

74LS90

74LS91

74LS92

74LS93

74LS95

74L596

74LS107

74LS109

74LS112

74LS113

74LS114

74LS122

74LS123

74LS124

74LS125

74LS126

74LS132

74LS136

74LS137

74LS138

74LS139

74LS145

74LS147

74LS148

74LS151

74LS153

74LS154

74LS155

74LS156

74LS157

74LS158

74LS160

74LS161

74LS162

74LS163

.25.25.25.25.25

25.35.25.25.35.35.451.00.35.25.35.25.35.35.35.25.35.55.55.35

25.55.75.75

75.25.35.351.25.40.45.50.40.50.751.15

40.65.89.70.65.85.95.40.40

45

45.50

45.952.99.95.85

75.55.99

75

.75

1.20

2.49

1.35

.75

752.35115

95

75

75.90.95.95.95

74LS16474LS16574LS16674LS16874LS16974LS17074LS17374LS17474LS17574LS18174LS18974LS19074LS19174LS19274LS19374LS19474LS19574LS19674LS19774LS22174LS24074LS24174LS24274LS24374LS24474LS24574LS24774LS24874LS24974LS25174LS25374LS25774LS25874LS25974LS26074LS26674LS27374LS27574LS27974LS28074LS28374LS29074LS29374LS29574LS29874LS32474LS35274LS35374LS36374LS36474LS36574LS36674LS36774LS36874LS37374LS37474LS37774LS37874LS37974LS38574LS38674LS39074LS39374LS39574LS39974LS44774LS49074LS66874LS66974LS67074LS67474LS68274LS68374LS68474LS68574LS68874LS689

LINEAR

LM301V

LM308V

LM309K

LM311

LM317T

LM317K

LM318

LM323K

LM324

LM337K

LM339

LM377

LM380

LM386V

LM555V

LM556

LM565

LM566V

LM567V

LM723

LM733

.34

.981.49641.953.951.494.95

.593.95

.99

2.29

1.29

1.50

39

69

.99

1.49

1 29

49

.95

.95

2.40

1.75

1.75

1.75

.80

.95

.95

2.15

9.95

1.00

1.00

.85

.95

1.00

.95

.85

.85

1.20

1.85

1.85

1.85

1.85

1.75

2.85

.76

1.25

.99

1.30

.85

.85

.85

2.85

.65

.55

1.65

3.35

.55

1.98

1.00

1.25

1.85

1.05

1.20

1.75

1.55

1.55

1.35

1.95

.95

.95

.70

.70

1.85

1.80

1.45

1.18

1.35

1.90

.65

1.90

1.90

1.65

1.70

.37

1.95

1.69

1.89

2.20

9.65

3.20

2.30

2.40

2.40

2.40

2.40

LM741V

.29

LM747

.79

LM74SV

.59

LM1310

2.90

MC1330V

1.89

MC1350V

1.29

MC1358

1 79

LM1414

1.59

LM1458V

.69

LM1488

.99

LM1489

.99

LM1800

2.99

LM1889

2.49

LM39O0

59

LM3909V

.98

LM3914

3.95

LM3915

3.95

LM3916

3.95

75451V

39

75452V

39

75453V

39

8202

8205

8212

8214

8216

8224

8226

8228

8237

8238

8243

8250

8251

8253

8253-5

8255

8255-5

8257

8259

8272

8275

8279

8279-5

8282

8283

8284

8286

8287

8288

8289

45.00

3.50"

1.95

3.90

1 85

2.50

1.85

4.95

19.95

4.95

4.50

14.95

5.50

9.85

9.85

5.25

5.25

9.00

7.00

39.95

29.95

10.50

10.50

6.65

6.65

5.80

6.65

6.65

25.00

49.95

6800

68006802680968106820682168286834684068436844684568476850685268606862687168756880

6.95

1 1.95

37.95

4.60

4.95

4.95

9.95

16.95

14.95

42.95

44.95

29.95

15.95

4 75

5.75

10.95

11.95

25.95

6.95

2.95

1702

2708

2758

TMS2516

2716

2716-1

TMS2716

TMS2532

2732

2101

2102-1

21L02-1

2111

2112

2114

2114L-2

2114L-3

2114L-4

TMS4044-4

TMS4044-3

TMM2016

HM6116

4027

4116-150

4116-200

4116-300

4164

803580398080A8085

8155

8156

8185

8185-2

8741

8748

8755

16.9519.953.9512.9599.9539.9511.9511.9529.9539.9539.9569.9549.95

Z80

Z80

Z80A

Z808

Z80-PI0

Z80A-PI0

Z80-CTC

Z80A-CTC

Z80-0AHT

Z80A-DART

Z80-DMA

Z80A-DMA

Z80-SIO/0

Z80A-SIO/0

Z80-SIO/1

Z80A-SI0/1

Z80-SI0/2

Z80ASIO/2

Z80-SIO/9

Z80ASIO/9

8.95

9.95

19.95

6.50

8.60

6.50

8.65

15.25

18.75

17.50

27.50

23.95

28.95

23.95

28.95

23.95

28.95

17.95

22.95

T.V.CIRCUITS

MC1330

MC1350

MC1358

LM380

LM386

LM565

LM741

LM1310

LM1800

LM1889

1.891.291.791.291 50.99.292.902.992.49

EPROMS

256 x 81 024 x 81024 x 82048 x 82048 x 82048 x 82048 x 84096 x 84096 x 8

(1us)(450ns)(450ns)(5v)(450ns)(5v)(450ns)(5v)(350nsM5v)(450ns)(450ns)(5v)(450ns)(5v)

STATIC RAMS

256 x 41024 x 11024 x 1256 x 4256 x 41024 x 41024 x 41024 x 41024 x 44096 x 14096 x 12048 x 82048 x 8

(450ns)

(450ns)

(450ns)(LP)

(450ns)

(450ns)

(450ns)

(200ns)(LP)

(300ns)(LP)

(450ns)(LP)

(450ns)

(300ns)

(200ns)

(200ns)

JDR MICRODEVJCES, INC IS PROUD TO

ANNOUNCE THE OPENING OF OUR

NEW RETAIL SHOWROOM

BAY AREA RESIDENTSSTOP BY 1224 BASCOM AVE.

MISC.

8T26

1.69

3242

9.95

8T28

2 49

AY5-1013 3.96

8T95

99

TR1602

4.95

8T96

.99

1M6402

7.95

8T97

.99

1771

24.95

8T96

.99

1791

36 95

1488

.99

1793

49,95

1489

.99

UPD765

39.95

DM8131

2.95

8272

39.95

1441 1

9.95

74C923

5.95

TRANSISTORS

PN22222N39042N39062N3055IN4148IN4004

10/1.00

10/1.00

10/1.00

.79

6502

6502

6.95

6502A

12.95

6504

6.95

6505

8.95

6520

4.95

6522

9.95

6532

14.95

6551

14.95

4.95

395

9.95

7.95

5.95

12.95

9.95

19.95

16.50

1.95

.89

1.29

2.99

2.99

8/17.95

8/22.95

8/21.95

8/18.95

3.49

3.99

CALL

CALL

DYNAMIC RAMS

4096 x 1 (250ns) 2.50

16,384 x 1 (150ns) 8/19.95

16,384 x 1 (200ns) 8/17.50

16,384 x 1 (300ns) 8/16.95

65,536 x 1 (200ns) CALLLP = LOW POWER

8pcs

4.50

3.50

8.95

6.95

5.50

11.95

8.95

17.95

15.95

100pcs1.85.851.152.492.792.102.452.452.253.253.75

100pcs2.002.351.951.85

100/8.99

100/8.99

100/8 99

10/6.99

25/1.00

10/1 00

MA1012ACLOCK MODULE

W RED LED CHARACTERS

12-HOUR FORMAT

FACTORY ASSEMBLED

JUST ADD SWITCHES

COMPLETE WITH SPECIALTRANSFORMER AND SPECS.

$8" ea. 3/$2400

CALL JDR BEFORE YOU BUY!WE WILL BEAT ANY COMPETITORS PRICES

800-538-5000800-662-6233

{CALIFORNIA RESIDENTS!

DIP SWITCHES

4 position

.85

5 position

.90

6 position

.90

7 position

.95

8 position

.95

CONNECTORS

RS232MALE

3.25

RS232 FEMALE

3.75

RS232HOOD

1.25

S-100ST

3.95

S-100WW

4.95

LEDS

Jumbo Red 10/1.0CJumbo Green 6/1.0CJumbo Yellow 6/1.0C5082-7760 .43'CC .79MAN74.3'CC .99

MAN72.3'CA .99

IC

SOCKETS

VOLT/

1-100 100p

8 pin ST .13

7805T

.89

7905T

.99

14 pin SI .15

7808T

99

7912T

.99

16 pin ST .17

7812T

.89

7915T

1.19

18 pin ST .20

781 5T

.99

7924T

1.19

20 pin ST .29

7824T

.99

22 pin ST .3024 pin ST .3028 pin ST .40

7805K

1.39

7905K

1.49

40 pin ST .49

7812K7815K

1.391.39

7912K79L05

1.49.79

ST = SOLDERTAIL8 pin WW .5914 pin WW .69

78L05

.69

79L12

79

16 pin WW .69

78L12

.69

79L15

.79

18 pin WW .99

78L15

.69

LM317K

3.95

20 pin WW 1.0922 pin WW 1.39 1

LM3U9K

1.49

LM323K

4.95

24 pin WW 149 1

LM317T

1.95

LM337K

3.95

28 pin WW 1.69 140 pin WW 1.99 1

T=TO-220 K=

=TO-3 L=TO-92

WW = WIREWRAP

JDR MICRODEVICES, INC.

aftffp- 1224 Bascom Ave.

(l'^ Campbell, CA 95008

ifs/it'' 800-538-5000 • 800-662-6233 (Calif.)& 408-247-4852

Circle 190 on inquiry card.

TERMS: For shipping include $2.00 for UPS Ground, $3.0UPS Blue Label Air. $10.00 minimum order. Bay Area Idents add 6VS% sales tax. California Residents add 6% !tax. We reserve the right to limit quantities and substmanufacturer. Prices subject to change without ncSend SASE for complete list.

2716

EPROMS 450NS (5V)

8/5.50

ALL MERCHANDISE 100% GUARANTEED!

CALL US FOR VOLUME QUOTES

CMOS

74C0O

.35

74C374

2.75

4019

.45

4098

2.49

74C02

.35

74C901

.80

4020

.95

4099

1.95

74C04

.35

74C902

.85

4021

.95

14409

8.95

74C08

.35

74C903

.85

4022

1.15

14410

8.95

74C10

.35

74C905

10.95

4023

.35

14411

9.95

74C14

1.50

74C906

.95

4024

.75

14412

12.95

74C20

.35

74C907

1.00

4025

.35

14419

2.95

74C30

.35

74C908

2.00

4026

1.65

4502

.95

74C32

.50

74C909

2.75

4027

.65

4503

.65

74C42

1.75

74C910

9.95

4028

.80

4508

1.95

74C48

2.10

74C911

10.00

4029

.95

4510

.95

74C73

.65

74C912

10.00

4030

.45

4511

.95

74C74

.85

74C914

1.95

4034

2.95

4512

.95

74C76

.80

74C915

2.00

4035

.85

4514

1.25

74C83

1.95

74C918

2.75

4040

.95

4515

2.25

74C85

1.95

74C920

17.95

4041

1.25

4516

1.55

74C86

.95

74C921

15.95

4042

.75

4518

1.25

74C89

4.50

74C922

5.95

4043

.85

4519

1.25

74C90

1.75

74C923

5.95

4044

.85

4520

1.25

74C93

1.75

74C925

6.75

4046

.95

4522

1.25

74C95

1.75

74C926

7.95

4047

.95

4526

1.25

74C107

1.00

74C927

7.95

4049

.55

4527

1.95

74C150

5.75

74C928

7.95

4050

.55

4528

1.25

74C151

2.25

74C929

19.95

4051

.95

4531

.95

74C154

3.25

74C930

19.95

4053

.95

4532

1.95

74C157

1.75

4000

.35

4060

1.45

4538

1.95

74C160

2.00

4001

.35

4066

.75

4539

1.95

74C161

2.00

4002

.25

4068

.40

4543

2.70

74C162

2.00

4006

.95

4069

.35

4555

.95

74C163

2.00

4007

.29

4070

.35

4556

.95

74C164

2.00

4008

.95

4071

.30

4581

1.95

74C165

2.00

4009

.45

4072

.30

4582

1.95

74C173

2.00

4010

.45

4073

.30

4584

.95

74C174

2.25

4011

.35

4075

.30

4585

.95

74C175

2.25

4012

.25

4076

.95

4702

12.95

74C192

2.25

4013

.45

4078

30

4724

1.50

74C193

2.25

4014

.95

4081

30

80C07

.95

74C195

2.25

4015

.95

4082

30

80C95

.85

74C200

5.75

4016

.45

4085

.95

80C96

.95

74C221

2.25

4017

1.15

4086

.95

80C97

.95

74C373

2.75

4018

.95

4093

.95

80C98

1.20

74S00 SERIES

44

74S74

.69

74S163

3.75

74S258

1.49

48

74S85

2.39

74S168

4.65

74S260

1.83

48

74S86

1.44

74S169

5.44

74S274

19.95

79

74S112

1.59

74S174

1.09

74S275

19.95

79

74S113

1.98

74S175

1.09

74S280

2.90

48

74S114

1.50

74S181

4.47

74S287

4.75

98

74S124

2.77

74S182

2.95

74S288

4.45

69

74S132

1.24

74S188

3.95

74S289

6.98

88

74S133

.98

74S189

14.95

74S301

6.95

70

74S134

.69

74S194

2.95

74S373

3.45

68

74S135

1.48

74S195

1.89

74S374

3.45

98

74S138

1.08

74S196

4.90

74S381

7.95

48

74S139

1.25

74S197

4.25

74S387

5.75

98

74S140

1.45

74S201

14.95

74S412

2.98

87

74S151

1.19

74S225

8.95

74S471

9.95

68

74S153

1.19

74S240

3.98

74S472

16.85

44

74S157

1.19

74S241

3.75

74S474

17.85

78

74S158

1.45

74S251

1.90

74S482

15.60

79

74S161

2.85

74S253

7.45

74S570

7.80

25

74S162

3.70

74S257

1.39

74S571

7.80

PROMS

74S188

(82S23)

OC

32x8

3.95

74S287

(82S129)

TS

256x4

4.75

74S288

(82S123)

TS

32x8

4.45

74S387

(82S126)

OC

256x4

5.75

74S471

TS

256 x8

9.95

74S472

(82S147)

TS

512x8

16.85

74S474

(82S141)

TS

512 x 8

17.85

74S570

(82S130)

OC

512x4

7.80

74S571

(82S131)

TS

512x4

7.80

7400 SERIES

7400

.19

74128

.55

7401

.19

74132

.45

7402

.19

74136

.50

7403

.19

74141

.65

7404

.19

74142

2.95

7405

.22

74143

2.95

7406

.22

74144

2.95

7407

.22

74145

.60

7408

.24

74147

1.75

7409

.19

74148

1.20

7410

.19

74150

1.35

7411

.25

74151

.65

7412

.30

74152

.65

7413

.35

74153

.55

7414

.55

74154

1.40

7416

.25

74155

.75

7417

.25

74156

.65

7420

.19

74157

.55

7421

.35

74159

1.65

7422

.29

74160

.85

7423

.29

74161

.70

7425

.29

74162

.85

7426

.29

74163

.85

7427

.29

74164

.85

7428

.45

74165

.85

7430

.19

74166

1.00

7432

.29

74167

1.95

7433

.45

74170

1.65

7437

.29

74172

5.95

7438

.29

74173

.75

7440

.19

74174

.89

7442

.49

74175

.89

7443

.65

74176

.89

7444

.69

74177

.75

7445

.69

74178

1.15

7446

.59

74179

1.75

7447

.69

74180

.75

7448

.69

74181

2.25

7450

19

74182

.75

7451

.23

74184

2.00

7453

.23

74185

2.00

7454

.23

74186

18.50

7460

.23

74190

1.15

7464

.39

74191

1.15

7465

.39

74192

.79

7470

.35

74193

.79

7472

.29

74194

.85

7473

.34

74195

.85

7474

.35

74196

.79

7475

.49

74197

.75

7476

.35

74198

1.35

7480

.59

74199

1.35

7481

1.10

74221

1.35

7482

.95

74246

1.35

7483

.50

74247

1.25

7484

.50

74248

1.85

7485

.65

74249

1.95

7486

.35

74251

.75

7489

4.95

74259

2.25

7490

.35

74265

1.35

7491

.40

74273

1.95

7492

.50

74276

1.25

7493

.49

74279

.75

7494

.65

74283

2.00

7495

.55

74284

3.75

7496

.70

74285

3.75

7497

2.75

74290

.95

74100

1.00

74293

.75

74107

.30

74298

.85

74109

.45

74351

2.25

74110

.45

74365

.65

74111

.55

74366

.65

74116

1.55

74367

.65

74120

1.20

74368

.65

74121

.29

74376

2.20

74122

.45

74390

1.75

74123

.55

74393

1.35

74125

.45

74425

3.15

74126

.45

74426

.85

74490

2.55

NEED FAST PARTS?

DYNAMIC RAMS

4116

150NS

16Kx 1

8/19.95

4116

120NS

16Kx 1

8/29.95

STATIC RAMS

2147

55NS

4Kx 1

9.95

6116

150NS

2Kx8

CALL

6116

120NS

2Kx8

CALL

EPROMS

2716-1

350 NS

2Kx8

12.95

2732A

250NS

4Kx8

25.95

2732A-2

200 NSMPU's

4Kx8

32.95

Z-80B

CPU

6mHz

19.95

Z-80B

CTC

6mHz

17.95

Z-80B

PIO

6mHz

17.95

68 BOO

CPU

2mHz

10.95

68B21

PIA

2mHz

12.95

68B50

ACIA

2mHz

12.95

8085A-2

CPU

5mHz

16.95

APPLE OWNERS

EXPAND YOUR 48K COMPUTER TO 64K

SUPER RAM • II

PLUG IN SLOT f) l!Kmx™,mmims

GOLD PLATED CONTACTS

INCLUDES 5 JUMPER OPTIONS

INCLUDES 5 RAM-ROM OPTIONS I

ENJOY THE BEST OF BOTH WORLDS 1

16K RAM (RANDOM ACCESS MEMORY) I

THIS IS SOPHISTICATED FIRMWARE

EXPANDS YOUR 48K APPLE TO 64K |

OF PROGRAMMABLE MEMORY

ELIMINATES THE NEED FOR APPLESOFT' OR INTEGER BASIC ROM

CARD

ALLOW YOU TO RUN APPLE'S NEW FORTRAN PACKAGE. ALSO

PASCAL AND PILOT

KEYBOARD CONTROL SELECTION OF RAM OR MOTHER BOARD

ROM LANGUAGE

INCLUDES INSTALLATION INSTRUCTIONS AND APPLICATIONS

NOTES

THE SOFTWARE DEVELOPED BY VARIOUS VENDORS FOR YOUR

(64K) SHOULD NOW WORK AS THEY ADVERTISED

THE MOST VERSATILE RAM EXPANSION ON THE MARKET TODAY

UNIQUE 1 YEAR WARRANTEE! $168.00

APPLE FAN

"COOL-/T"TAN COLOR

• SAVE DOWN TIME

• LONG LIFE MOTOR

• LOW NOISE IS A MUST

• SAVE REPAIR CHARGES

• INCREASES RELIABILITY

• CLIPS ON — NO HOLES OR SCREWS

• MINIMUM QUIETNESS IS DUE TO THE DRAW EFFECT OF AIRTHROUGH YOUR COMPUTER AND A SPECIAL FAN AND MOTORDESIGN

• THOSE EXTRA PLUG-IN CARDS CAN CAUSE EXTRA HEATHOW TO HOOK IT UP

1. Clip it on your APPLE

2 Unplug your 120V cable {you won't need it)

3. Plug short 120V cable Irom Super Fan II to the back ot your computer

4. Plug the supply cable Irom Super Fan II to your 120V power source

5. Turn on the rocker switch and a built-in red ready light comes on

6. You are all set "COOL IT"

UNIQUE 1 YEAR WARRANTEE! $69.00

•APPLE IS A TRADEMARK OF APPLE COMPUTER INC.

master charge!

JDR MICRODEVICES, INC.

g^c' 1224 Bascom Ave.

Campbell, CA 95008

800-538-5000 • 800-662-6233 (Calif.)408-247-4852

TERMS For shipping include $2.00 lor UPS Ground. $3.00 lorUPS Blue Label Air. $10.00 minimum order Bay Area Resi-dents add 6'/?% sales tax California Residents add 6% salestax. We reserve the right to limit quantities and substitutemanufacturer. Prices subject to change without notice.Send SASE tor complete lisl

Circle 190 on inquiry card.

4K STATIC RAM 8/$20.00

2114 LOW POWER 200 NS

74LS00

74LS00

.25

74LS123

.90

74LS259

2.80

74LS01

.25

74LS124

2.95

74LS260

.60

74LS02

.25

74LS125

.90

74LS261

2.45

74LS03

.25

74LS126

.80

74LS266

.50

74LS04

.25

74LS132

.75

74LS273

1.60

74LS05

.25

74LS136

.50

74LS275

3.30

74LS08

.30

74LS138

.75

74LS279

.50

74LS09

.25

74LS139

.75

74LS280

1.95

74LS10

.25

74LS145

1.10

74LS283

.95

74LS11

.30

74LS147

2.25

74LS290

1.20

74LS12

.30

74LS148

1.25

74LS293

1.80

74LS13

.40

74LS151

.75

74LS295

1.00

74LS14

.75

74LS153

.75

74LS298

.95

74LS15

.30

74LS155

.90

74LS299

2.50

74LS20

.25

74LS156

.90

74LS323

3.95

74LS21

.30

74LS157

.75

74LS324

1.75

74LS22

.25

74LS15B

.75

74LS347

1.95

74LS26

.30

74LS160

.90

74LS348

1.95

74LS27

.35

74LS161

.90

74LS352

1.50

74LS28

.35

74LS162

.90

74LS353

1.50

74LS30

.25

74LS163

.90

74LS363

1.35

74LS32

.35

74LS164

.90

74LS365

.90

74LS35

.55

74LS165

.90

74LS366

.90

74LS37

.50

74LS166

2.00

74LS367

.65

74LS38

.35

74LS168

1.70

74LS368

.65

74LS40

.25

74LS169

1.70

74LS373

1.15

74LS42

.50

74LS170

1.70

74LS374

1.75

74LS47

.75

74LS173

.75

74LS375

.65

74LS48

.75

74LS174

.90

74LS377

1.40

74LS49

.75

74LS175

.90

74LS385

1.85

74LS51

.25

74LS181

2.10

74LS386

.60

74LS54

.35

74LS189

9.95

74LS390

1.85

74LS55

.35

74LS190

.95

74LS393

1.85

74LS63

1.20

74LS191

.95

74LS395

1.60

74LS73

.35

74LS192

.80

74LS399

1.65

74LS74

.40

74LS193

.90

74LS424

2.95

74LS75

.50

74LS194

.95

74LS447

.35

74LS76

.40

74LS195

.90

74LS490

1.90

74LS78

.50

74LS196

.80

74LS630

75.00

74LS83

.75

74LS197

.80

74LS640

3.00

74LS85

1.10

74LS221

1.15

74LS641

3.00

74LS86

.40

74LS240

1.15

74LS642

3.00

74LS90

.60

74LS241

1.15

74LS645

3.00

74LS91

.80

74LS242

1.85

74LS668

1.65

74LS9274LS93

.65.60

74LS24374LS244

1.851.00

74LS66974LS670

1.852.15

74LS95

.80

74LS245

1.95

74LS674

9.60

74LS96

.80

74LS247

.75

74LS682

3.15

74LS107

.40

74LS248

1.20

74LS683

2.25

74LS109

.40

74LS249

.95

74LS684

2.35

74LS112

.40

74LS251

1.25

74LS685

2.35

74LS113

.40

74LS253

.80

74LS688

2.35

74LS114

.50

74LS257

.80

74LS689

2.35

74LS122

.45

74LS258

.80

4000CMOS

4000

.35

4040

.95

4501

.50

4001

.35

4041

.95

4502

.95

i 4002

.35

4042

.75

4503

.65

4006

.95

4043

.85

4505

8.95

4007

.35

4044

.85

4506

1.25

4008

.95

4046

.95

4507

.95

4009

.45

4047

.95

4508

1.95

4010

.45

4048

.75

4510

.95

4011

.35

4049

.55

4511

.95

4012

.35

4050

.55

4512

.95

4013

.45

4051

.95

4514

2.25

4014

.95

4052

.95

4515

2.25

4015

.95

4053

.95

4516

1.50

4016

.45

4055

;

2.75

4518

1.25

4017

.95

4056

2.75

4519

1.25

4018

.95

4059

9.95

4520

1.25

4019

.45

4060

■

1.25

4522

1.25

4020

.95

4066

.75

4526

1.25

4021

.95

4068

.40

4527

1.75

4022

.95

4069

.40

4528

1.25

4023

.35

4070

.40

4531

.95

4024

.75

4071

.30

4532

1.75

4025

.35

4072

.30

4539

1.75

4026

*

1.95

4073

.30

4543

1.95

4027

.65

4075

.30

4553

4.95

4028

.80

4076

95

4555

.95

4029

.95

4078

.50

4556

.95

4030

.45

4081

.40

4558

2.25

4031

■

1.50

4082

.40

4568

5.95

4032

2.75

4085

.95

4581

1.95

4033

;

2.75

4086

.96

4582

1.95

4034

;

!.75

4093

.95

4584

.95

4035

.85

4094

;

J.95

4585

.95

4037

■'

>.50

4099

1.75

4702

9.95

74S00

74S00

.40

74S163

3.70

74S02

.45

74S168

4.60

74S03

.45

74S169

5.40

74S04

.75

74S174

1.05 ',

74S05

.75

74S175

1.05

74S08

.45

74S181

4.45

74S09

.75

74S182

2.90

74S10

.65

74S188

3.90

74S11

.80

74S189

14.90

74S15

.65

74S194

2.90

74S20

.65

74S195

1.85

74S22

.75

74S196

4.85

74S30

.45

74S197

4.20

74S32

.95

74S201

14.90

74S37

1.85

74S225

8.90

74S38

1.65

74S240

3.95

74S40

.40

74S241

3.70

74S51

.75

74S251

1.85

74S64

.75

74S253

7.40

74S65

1.20

74S257

1.35

74S74

.65

74S258

1.45

74S85

2.35

74S260

1.80

74S86

1.40

74S274

19.90

74S112

1.55

74S275

19.90

74S113

1.95

74S280

2.85

74S114

1.45

74S2B7

4.70

74S124

2.75

74S288

4.40

74S132

1.20

74S289

6.95

74S133

.95

74S301

6.90

74S134

.65

74S373

3.40

74S135

1.45

74S374

3.40

74S138

1.05

74S381

7.90

74S139

1.20

74S387

5.70

74S140

1.40

74S412

2.95

74S151

1.15

74S471

9.90

74S153

1.15

74S472

16.80

74S157

1.15

74S474

17.80

74S158

1.40

74S482

15.50

74S161

2.80

74S570

7.75

74S162

3.70

74S572

7.75

74C00 CMOS

74CO0

.35

74C195

2.20

74C02

.35

74C221

2.20

74C04

.35

74C240

2.20

74C08

.35

74C244

2.20

74C10

.35

74C373

2.70

74C14

1.45

74C374

2.70

74C20

.35

74C901

.80

74C30

.35

74C902

.80

74C32

.50

74C903

.80

74C42

1.70

74C904

.80

74C48

2.05

74C905

10.90

74C73

.65

74C906

.90

74C74

.85

74C907

.90

74C76

1.90

74C908

2.00

74C83

1.90

74C909

2.70

74C86

.90

74C910

9.90

74C89

4.50

74C911

9.90

74C90

1.70

74C912

9.90

74C93

1.70

74C914

1.90

74C95

1.70

74C915

1.90

74C107

.95

74C917

2.70

74C150

5.70

74C918

1.90

74C151

2.20

74C920

16.00

74C154

3.20

74C922

5.90

74C157

1.75

74C923

5.90

74C160

1.95

74C925

6.70

74C161

1.95

74C926

7.90

74C162

1.95

74C927

7.90

74C163

1.95

74C928

7.90

74C164

1.95

74C929

7.90

74C165

1.95

74C930

7.90

74C173

1.95

74C932

1.95

74C174

2.20

74C941

2.75

74C175

2.20

74C989

9.90

74C192

2.20

80C95

.85

74C193

2.20

80C96

.90

80C97

.90

88C30

3.95

82C19

4.95

88C29

3.95

800-426-2668206-643-0792

LINEAR

7805CT

.85

LM301V

.75

LM567V

1.25

LM308V

.75

LM723

.50

7812CT

.85

LM309K

1.50

LM733

.95

7815CT

.95

LM311V

.60

LM741V

.30

LM317T

1.90

LM747

.75

7805KT

1.40

LM317K

3.75

LM748V

.60

7812KT

1.40

LM318N

1.50

LM1414

1.50

7815KT

1.40

LM323K

3.75

LM1458V

.65

78L05

.65

LM324N

.60

DS1488N

1.00

78L12

.65

LM337K

3.95

DS1489D

1.00

7905CT

.95

LM339

.75

LM1889

2.45

7912CT

.95

LM377

2.25

LM3900

.60

7915CT

1.15

LM380

1.25

LM3909

.90

LM386V

1.25

LM3914

3.75

7905K

1.50

LM3915

3.75

7912K

1.50

LM555V

.40

LM3916

3.75

79L05

.75

LM556

.70

DS75451

.40

79L12

.75

LM565

.95

DS75452

.40

■79L15

.75

LM566V

1.50

DS75453

.40

■ ■

■ ' •

HANLEY ENGINEERING CORP

13400 Northrup Way #20

Bellevue, WA. 98005

1-800-426-2668 1-206-643-0792

Include 3.00 for Ups GroundInclude 4.00 for Ups BlueInclude 4.00 for 1st Class MailWashington State add 5.4% Sales Tax

524 BYTE October 1981

Circle 164 on inquiry card

16K Memory 8/$16.00

4116 200NS

8200

8156

8185

8202

8205

8212

8214

8216

8224

8226

8228

8238

8243

8251A

8253

8255A-5

8257-5

8259A

8271

8272

8275

8279-5

8282

8283

8284A

8286

8287

8288

8289

8755A

11.25

29.95

45.00

3.95

1.90

3.85

1.80

2.50

1.80

4.90

4.90

4.50

5.45

9.80

5.20

8.95

6.95

60.00

39.95

29.95

10.00

6.60

6.60

5.75

6.60

6.60

25.00

49.95

45.00

CPU

8085A

8085A

8085A-2

8086

8088

8748

3.958.9511.9599.9539.9530.00

Z80

ZBO

6.70

zaoA

7.25

Z80B

19.00

ZBO PIO

6.00

Z80A IO

7.10

Z80B PIO

15.50

ZBO CTC

6.00

Z80A CTC

7.10

Z80B CTC

15.50

ZBO DMA

18.50

Z80A DMA

22.50

Z80 SIO / 0

18.50

Z80A SIO/0

22.50

ZBO SIO/1

18.50

Z80A SIO /1

22.50

Z80 SIO/2

18.50

Z80A SIO/2

22.50

6800

3242

8.00

3480

9.00 :

6800

5.75

6802

11.00

6809

25.00

6810

3.50

6821

3.50

6840

9.00

6843

41.00

6845

22.00

6847

12.25

6850

3.50

6852

3.50

6875

7.00

6B80

1.80

6882

4.70 I

6885

1.80

6888

1.80

6B89

1.80

6B488

12.50

6502

6502

7.90

6502A

10.00

6504

8.45

6504A

9.30

6512

9.20

6512A

10.00

6520

4.40

6521

6.15

6521A

6.70

6522

8.75

6522A

11.70

6532

11.25

6532A

12.40

6545-1

22.50

6545A-1

28.95

6551

11.95

6551A

12.95

CALLHANLEY FIRST

800-426-2668206-643-0792

EPROMS

2708

AMD

3 Supply

450NS

3.50

2716

Hitachi

+ 5

450NS

7.00

2716

National

+ 5

450NS

7.00

2716

Intel

+ 5

450NS

7.00

2716-1

Intel

+ 5

350NS

9.50

2716

T.I.

3 Supply

450NS

7.50

2716

Motorola

3 Supply

450NS

7.50

2732

NEC

+ 5

450NS

16.00

2732

Mitsubish

+ 5

450NS

16.00

2732

Intel

+ 5

450NS

17.00

7232A

Intel

+ 5

250NS

17.00

2732A - 3

Intel

+ 5

300NS

16.00

2732A - 2

Intel

+ 5

200NS

20.00

2532

Hitachi

+ 5

450NS

18.00

AUGAT LOW PROFILE SOCKETS

These Are High Reliability Ind

ustry

Standard Sockets

8PIN 208-AG29D

.10

8PIN 208-AG29D

.10

14PIN 214-AG29D

.16

16PIN 216-AG29D

.18

18PIN 218-AG29D

.20

20PIN 220-AG29D

.22

22PIN 222-AG29D

.24

24PIN 224-AG29D

.26

28PIN 228-AG29D

.28

40PIN 240-AG29D

.42

4K x 1 STATIC RAM

416464 x 1

MOTOROLA MCM6641-20

4044-200NS EQUIV.

200 NS

$4.50

CALL

SOLID STATE

SCIENTIFIC

HITACHI

256 x 4 CMOS RAM 450NS

2K

x 8 CMOS RAM 1S0NS

SCM5101E-1

Pin

Compatible with 2716

$3.75

HM6116P-3 CALL

HANLEY ENGINEERING CORP

13400 Northrup Way #20

Bellevue, WA. 98005

1-800-426-2668

1-206-643-0792

Include 3.00 for Ups GroundInclude 4.00 for Ups BlueInclude 4.00 for 1st Class MailWashington State add 5.4% Sales Tax

Circle 164 on inquiry card.

BYTE October 1981 525

Unclassified Ads

FOR SALE: H-8, serial I/O board, 20 K programmablememory, Extended BASIC, and all documentation. $500. 10%with balance COD. M H Endres, Box 8, Spirit Lake ID 83869.|208J 623-591 I.

FOR SALE: Slightly used Apple (I disk drive without con-troller. Less than 6 months old. S250 or best offer. Bill Wertlmg,14 Rego Ave. Centereach NY I 1720.

FOR SALE: Complete system: IMSAI 8080 computer with64 K memory, Lear-Siegler ADM-3 terminal, and Altair diskdnve. Good condition. Best offer on all three. Jim Fritz. 1413Harmony Ln. Annapolis MD 21401, (301) 757-7019.

WANTED: Complete documentation for Digital SystemsDSC-2 microprocessor and disk, Texas Instruments TI-810printer, and ADM-3A terminal. All missing when purchased atauction. Also, need information on adding lowercase to printerand display. Please state price in letter. N C Helmkay, POB 446,Milliken Ontario. L0H IK0 Canada, [416) 297-4337 after 6 PMET

FOR SALE: Complete Space Invaders board set. includingpower-supply board [the arcade version). An 8080A-basedcomputer with high-resolution composite video output and ex-tensive sound-synthesizing capability. No read-only memo-ries—needs 2116. 2708, or equivalent. Full schematic included,program listing available. S150. Send check or SASE for moreinformation. Rom Mahboubi, 910 S Orange Ave, Short Hills NJ07078.

FOR SALE: IBM 3275 Model 2 display terminal with key-board and documentation. Excellent condition. S1200. BPelkey. [305) 862-0875.

FOR SALE: ASR33 Teletype with paper-tape reader/punch,modem, touch-tone telephone pad. and stand; S425. Altair8800A computer with S-100 bus, 24 K programmable memory,and serial/parallel I/O; S550. Heathkit IM-16 voltmeter; SI8.TRW MPY-16 high-speed 16- by 16-bit multiplier chip; S40.Lenny Heath. 6618-D Lake Hill Dr, Raleigh NC 27609. |919)876-4168.

FOR SALE: Heath H-14 printer. Like new. S400 plus ship-ping. Dr Walt Atkins, Qtrs 44I0A. USAF Academy CO 80840.(303) 472-1362.

FOR SALE: BYTE #1 thru August 1979. 48 issues; S100 orbest offer. Extra BYTEs #1 thru #4; best offer. Kilobaud Micro-computing #1 thru August 1978. 20 issues. S50 or best offer.Extra Kilobaud Microcomputing #l thru #5; best offer. HP-524Dcounter, 525C 100 thru 500 MHz, 525A 10 thru 100 MHz,526A video amplifier, 526C period multiplier, plug-ins, manuals,used as laboratory standard, best reasonable offer. SandyFrazier. 5325 Curry Ford Rd #A203, Orlando FL 32806.

WANTED: A source of programs on Tarbell cassettes. I'vejust bought a Tarbell interface board to act as archival storage,and want to correspond with a Tarbell users group or an in-dividual with programs to sell or trade. Has anybody interfacedthe Tarbell board to the Mega tape system, ALPHA-1. using theS-100 bus? I would like to hear from you. Duane L Erwm, 335 SWabash. Bradley IL 60915, [815) 933-7566 days.

WANTED: Computer Music Journal back issues; volume 1.numbers 1, 2, and 4. John Valente, Box 9, Marlboro VT 05344.

WANTED: Used Apple II disk drive [DOS 3.3) with con-troller card. Give price and all pertinent details. Michael Levin.18 Peacock Farm Rd. Lexington MA 02173. [617] 862-5134collect.

FOR SALE: Model ASR33 teletypewriter. Extra ribbons andpaper. Manuals and schematics. S450. Will deliver within 200miles of Alamogordo. David L Marshall. 1803 Scenic Dr,AlamogordoNM 88310. |505) 437-6374.

WANTED: A Digital Group Systems digital cassette drive(Phi-Deck). It should be in good condition with the original con-nectors, and in the range of S50 to S100. Send name, phone,hours you can be reached, and price. Brad Manske, 1 3 1 5 W5th. North Platte NE 69101.

FOR SALE: Heath-89 48 K programmable memory, serialinterface board, one floppy. HDOS plus Heath BASIC and as-sembly-language programming courses, and extras. SI900.John Guernero, 172 Ludlam Ave. Elmont NY I 1003, |516)354-1797.

FOR SALE: KIM-1 microcomputer with manuals and powersupply; S125. KIM 6502 software [books, games, applications);S20. 77-key ASCII-encoded, word-processing keyboard. Ex-cellent condition, documentation included; S45. Mark Beall.2505 Manorwood Dr, Puyallup WA 983 7 1.

FOR SALE: Integer firmware card for Apple II plus. IncludesProgrammer's Aid No. I; S100. Fied M Gentile. 10182 ValleyForge Dr, Huntington Beach CA 92646. (714) 962-844 7

FOR SALE: AJ 841 terminal. IBM 2741 equivalent withacoustic coupler. Like new. Recently factory adjusted 15-mchwide platen. Very high-quality Selectnc mechanism S840. RDobbs, I 746 Clarkson Rd #G, Richmond VA 2322^.

SWAP: TRS-80 Model I, Color, or Model III cassette pro-grams. Games, information processing, and machine-languagemonitor. No business or education. Also, have M3 machine-language utilities and programs. Send cassette with a few ofyour programs and your needs (500 bps for I and III) and I willreturn it with the best of mine. Would also like information onyour M3 disk experiences. Steve Kolokowsky, 8 Wilson Ct,Spring Valley NY 10977.

FOR SALE: Heath H-14 printer. Nearly new. calibrated at aHeath center. S490. Neal De Loye. Rte 1. Onalaska Wl 54650,(608) 783-7767 evenings.

FOR SALE: Ithaca Intersystems Z80-based S-100 processorboard. Socketed, populated |on-board 2708 I K EPROM in-cluded), assembled and tested; S110. SI 00 8 K Ithaca Inter-systems static-memory board. Uses 2102 chips, fully socketed,2 K populated; S60. Parallel ASCII keyboard. Assembled andtested, in chassis with power supply. TTL parallel ASCII outputwith data-valid strobe; 560. Highest bidder takes. Send SASERoy Makrucki, 251 Pleasant Ridge Dr. Saline Ml 48176, |3!3)429-1286.

WANTED: Hewlett-Packard HP-9 7 calculaiot HVerhoeven. Box 4636, Mountain View CA 94040.

FOR SALE: Quest Super ELF with low-address display op-tion. S85. Glenn Andreas. Rte 1-7600 Hwy D East. LakeTomahawk Wl 54539.

FOR SALE: 10 MHz 8086 processor; S60. Intersil IM6100Family Sampler (PDP-8 with I K read-only memory monitor,256 words programmable memory, serial I/OJ; S50. Program-mable/EPROM memories (eight 4 K by I programmable memo-ries, six 2716 and one 2708 EPROMs); S75. IC grab bag [forty-five 7400 series digital, ten op amps, voltage regulators, sevensegment LEDs); S 1 5. Gregg Marshall. 967 Almond Dr, OakleyCA 94598.

FOR SALE: 32 K TRS-80 Model I with TRS-80 disk drive andTRSDOS. Includes all manuals, cassette player, all cables, andTRS-80 Editor/Assembler. Other software includes Space In-vaders and other games. S1800. Robert Topping, 17 CognacDr, Lake Saint Louis MO 63367.

FOR SALE: Brand-new SD Systems SBC-200 single-boardcomputer and SD Systems Versafloppy II disk controller.Assembled and tested by SD Systems. Total list price is S840.Will sell for S600 if purchased together. James Adams, 6405Maryland Ave, Hammond IN 46323, (219) 844-4691. No col-lect calls accepted.

FOR SALE: New original package: LOBOS 8-inch dual-drive cabinet plus power supply, Technico TI9900, 16-bit pro-cessor system, 64 K programmable memory, disk-controllerboard, DOS, 3.0 Super BASIC plus EAL. Perfect operating condi-tion. Full documentation and schematics. S3500 or best offer.Sam White, 643 Indiana Ave. Venice CA 90291. (213|549-2500 or 396-0936.

FOR SALE: Word processor/text editor for North Star. In-cludes utility programs with documentation on disk. Needsonly 24 K. BASIC, and one disk. Easy-to-use line-oriented editorworks with any ASCII terminal, including Teletype or CRT.Word processor allows commands in the file, and chaining toother text files, like subroutines in a program. S30. Mark Arnold,1400 Grand Ave. Laramie WY 82070.

FOR SALE: Commodore PET 2001 computer. Original 8 Kversion with video buffer and twelve program tapes, includingMicrochess 2.0- S500. Floyd Wilson, 903 W Sweet Ave,Bismarck ND 58501. (701) 258-9023.

FOR SALE: MicroAce ZX80 2 K [like Sinclair) with manual[Sinclair manual, too) and power pack in original box. Worksgood. Fantastic for the beginner learning BASIC or the ex-perienced Z80 machine-language programmer. First moneyorder for SI 29 takes it. M Neidich, 18 Hillside Ln N. Syosset NYI 1791. (516) 921-3603.

UNCLASSIFIED POLICY: Readers who are soliciting or giving advice, or who haveequipment to buy, sell or swap should send in a clearly typed notice to that effect. To beconsidered for publication, an advertisement must be clearly noncommercial, typed doublespaced on plain white paper, contain 75 words or less, and include complete name andaddress information.

These notices are free of charge and will be printed one time only on a space availablebasis. Notices can be accepted from individuals or bona fide computer users clubs only. Wecan engage in no correspondence on these and your confirmation of placement is ap-pearance in an issue of BYTE.

Please note that it may take three or four months for an ad to appear in the magazine.

FOR SALE: VDB-8024 video board. S-100. assembled andtested, 80 columns by 24 lines. Video enhancements includescroll, tab, reverse, blinking, and underline. Protect feature. 32special characters, including Greek and math symbols. Ad-dressable cursor. Very fast. Complete documentation includedStill under warranty. S275 plus COD. Tom Kirby. 318 W Clay,Blacksburg VA 24060.

FOR SALE: Alpha Micro computer system: AMI00 64 Kprocessor, SOROC IQ 120 terminal, AM20O floppy-disk con-troller board, AM300 G port serial I/O mux. Wangco/Orbis 87dual-disk dnve. TI-810 serial printer. Business software availableBest offer. Ron Bogaards, 108 Peace St. Pella IA 50219. (515)628-9295.

FOR SALE: SwTPC 68/2, two serial, one parallel. 20 K pro-grammable memory, 4 K EPROM. EPROM programmer anderaser, JPC cassette interface and recorder, CFM. two memory-mapped video boards, lots of software, and twenty cassettesIn excellent condition with complete documentation for S600.Also, AC-30; S75. Send SASE for more details. Joe Williams.2780 Janitell Rd. Colorado Springs CO 80906. |303) 599-4828or 473-8060 evenings.

FOR SALE: S-100 boards: TDL Z80 ZPU, SMB1, SMB2.

parallel I/O (4 ports], four 16 K programmable memories, JadeZ80 4 MHz. S50 each. KIM-I system: 40 K. ASCII keyboard.TV interface, power supply, software, and BASIC. S 160. Jade:two 8-inch dual-disk/double-density controller drives. PROMboot, CP/M 2.2, cabinet, power supply, cables, manuals,system disks, and utilities. For S-100. Used approximately twohours. Cost S 1400. Sell S700. Send money order or cashier'scheck and phone number (confirmation of sale). Brian Graves.Abbot Hill Rd, Wilton NH 03086.

526 October 1981 © BYTE Publications Inc

Reader Service

Inquiry No.

Page No.

1 47th STREET PHOTO 437

2 A B DIGITAL DESIGN 55

3 AB COMPUTERS 495

4 ABM PRODUCTS 424

5 ACKERMAN DIGITAL SYS 58

• ACTION COMPUTER 167

6 ADAPTIVE DATA & ENERGY 145

7 ADDMASTER CORP. 504

8 ADV.COMP.PROD. 514, 515

9 ADV.MICRO SYS. 66

10 ADV.OPERATING SYS. 143

11 ADVANCED TECH 494

12 ADVENTURE INT'L. 117

• ALF PRODUCTS, INC 382

13 ALPHA BYTE STORAGE 51

14 ALPHA BYTE STORAGE 124, 125

15 ALSPA COMP.SYS. 496

17 ALTOS COMP.SYS. 88, 89

428 AMERICAN COMP. & ENG 107

18 AMDEK CORP. 162

19 AMER.COMP.EXCH. 494

• AMER.SFTW.CLUB 219

21 AMER.SQUARE COMP. 237

22 ANCIE LABS 106

23 ANCRONA222

24 ANDERSON JACOBSON 440

25 ANTEX DATA SYS. 130

26 APPARATINC 129

27 APPARAT INC 327

• APPLE COMPUTER INC 12

28 APPLE COMPUTER INC 13425 APPLE COMPUTER INC 13

29 APPLIED ANALYTICS 132

30 ARTIFICIAL INTL.RESRCH 494

31 ASAPCOMP.PROD.INC. 314, 315

32 ASAPCOMP.PROD.INC. 345

33 ASHTON-TATE 282, 283

427 ATLANTIC COMPUTER, IND. 336

34 ATARI 347

35 ATARI.INC. 61

16 ATON INT'L. 142418 AURORA 371

36 AUTOCONTROL INC 210

37 AUTOMATED CONTR.SYS. 500

38 AUTOMATED EQUIPMNT. 433

39 AUTOMATED EQUIPMNT. 457

• AVOCET 224

40 B&B ELECTR. 496

41 BASF SYSTEMS 303

■ BELL.JOHN ENGI1 481

• BETA COMP.DEVICES 259

43 BISON PRODUCTS 491

44 BIZCOMP 301

45 BLUE LAKES COMPUTING 296

46 BOURBON ST.PRESS 450

47 BOWER-STEWART 494

49 BUSINESS OPERTING SYS 27

50 BUSINESS WEEK 281

• BYTE BOOKS 233

51 BYTE BOOKS 234

52 BYTE BOOKS 235

53 BYTE BOOKS 236

• BYTE PUBL.INC. 398

• C.S.MARKETING 165

61 CALIF.COMP.SYS 91

54 CALIF DATA CORP 492

55 CALIF. DIGITAL 509, 510

56 CALIF. DIGITAL 511

• CALIF.MICROCOMP. 369

58 CAMBRIDGE UNIV.PRESS 358

59 CAMEO ELECTR.INC 119

60 CAMRODEN CO..THE 502

• CARRINGTON CO..THE 502

62 CDR 498

81 CDS 354

63 CER-TEK INC 502

64 CHECK-MATE 496

65 CHECKS-TO-GO 118

66 CHIPS & DALE 500

67 CHRISLIN INDUSTRIES 271

68 CMC.INT'L. 389

69 CODE WORKS.THE 122

70 COLONEY PRODUCTIONS 443

71 COLONIAL DATA SERVICE 362

73 COMPILER SYS.INC 335

74 COMPONENTS EXPRESS 360

75 COMPUDIAL.INC. 104

76 COMPUMART 120, 121

78 COMPUPRO/GODBOUT 203

77 COMPUPRO/GODBOUT 248, 249

79 COMPUSERVE 262, 263

80 COMPUTER AGE 434

82 COMPUTER DISC.OF AM. 272

83 COMPUTER EXCHANGE 276, 277

Inquiry No.

Page No.

84 COMPUTER FURN.& ACCSS. 421

85 COMPUTER MAIL ORDER 289

86 COMPUTER PLUS 496

87 COMPUTER SHOPPER 445

88 COMPUTER SPCLTIES. 100, 101

89 COMPUTER STOP, THE 483

• COMPUTER WRHSE. 123

90 COMPUTERS ETC. 409

91 COMPUTERS ETC. 418

92 COMPUTERS ETC. 450

93 COMPUTERS PERIPH.UNLTD 395

94 COMPUTERS WHOLESALE 485

95 COMPUTERWARE 338

96 COMPUTEX CORP 254

97 COMPUTIQUE337

412 COMPUVIEW PROD.INC. 68

413 COMPUVIEW PROD.INC. 68

98 COMPUVIEW PROD.INC. 69

99 CONCOMP IND. 371399 CONCOMP IND. 384

101 CONCORD COMP.PROD. 435

102 CONSUMER COMP. 148, 149

103 CONSUMER COMP. 503

105 COVER CRAFT 220

106 CPI 134

107 CPU SHOP, THE 479

108 CROMEMCO CM, 1

109 CROMEMCO 2

• CYBERNETICS, INC. 293407 D &W DIGITAL 174

• DATA DISCOUNT CTR 416

111 DATAFACE2B

■ DATASAAB 246

414 DATASOFT355

112 DATASOUTH COMP.CORP. 159

113 DATASOUTH COMP.CORP. 348

114 DELTA PRODUCTS 275

117 DESIGNER SOFTWARE 103

• DFS COMP.FORMS 286

118 DIABLO SYS INC 261

119 DIGIAC CORP 387

120 DIGITAL ELECT.SYS. 164

121 DIGITAL GRAPHIC SYS 302

122 DIGITAL MARKETING 6

123 DIGITAL MARKETING 307

124 DIGITAL RESEARCH 171

125 DIGITAL RESEARCH 377

• DIGITAL RESEARCH COMP. 493

126 DILITHIUM PRESS 453

127 DISC/3 MART INC. 380

128 DISCOUNT SFTW.GRP.THE 274

• DISK SUPPLY 442

129 DISKONNECTION.THE 504

130 DUAL SYS.CONTROL CORP. 60

131 DUAL SYS.CONTROL CORP. 62

132 DUAL SYS.CONTROL CORP. 64

133 DUOSOFT CORP. 181

140 DUPRE ENTERPRISES.INC. 397

134 DYMARC IND. 393

135 DYNACOMP 330, 331

137 ECOSOFT292

• EDMUND SCIENTIFIC CO 180

138 ELECTROLABS 490

139 ELECTRONIC CONTROL 270

141 ELECTRONIC SPCLISTS 391

142 ELECTRONIC SYS.FURN 420

143 ELECTRONICS CENTER 488

• ELECTROVALUE 260416 ELLIS 460

410 EMPIRE SYS.CORP 502

144 EMPIRICAL RESRCH GRP. 502

145 EMPIRICAL RESRCH GRP. 504

• END USER SOFTWARE 350

147 EPSON AMERICA 297

148 EQUITABLE MONEY MRK. 447

• ESCON 398

149 ESSEX PUBLISHING 390

150 EXPOTEK 439' FAIRCOM 256

151 FARNSWORTH COMP.CTR. 374

152 FINANCIAL SFTW.SYS. 502

153 FORETHOUGHT PRODUCTS 364

154 FREDERICK COMP.PROD. 431

155 FSS 496274 FUTRA317

156 FYI INC. 496

157 GEORGIA EXEC.MICRO 294

158 GIMIX INC 46

159 GIMIX INC 492

160 GRAFFCOM SYS. 20

161 H & ECOMPUTRONICS 255

162 H & E COMPUTRONICS 257

163 HANDICRAFTS 504

164 HANLEY ENGNRING 524, 525

Inquiry No.

Page No.

165 HAPPY HANDS 386

166 HAYDEN BOOK CO INC 363

167 HAYES MICROCOMP.PROD. 161

• H EATH COM PAN Y 16, 17, 217

168 HEWLETT-PACKARD 137

169 HOUSTON INSTRUMENTS 49

170 HOUSTON INSTRUMENTS 49

171 HOWE SOFTWARE 498

172 I.B.C. 188426 IMS INT'L. 67

174 INFOSOURCE.INC. 128

175 INMAC 386

176 INNER ACCESS 504

177 INNOVATIVE PROD. 312

178 INNOVATIVE SFTW.APPL. 72

179 INSOFT CORP. 53

180 INTEGRAL DATA SYS. 63

181 INTEGRAND 384405 INTEL 152, 153

183 INTERTEC DATA SYS. 175

184 IPEX INT'L. 494

185 ITHACA INTERSYSTEMS 8, 9

186 ITHACA INTERSYSTEMS 239

187 JADE COMP.PROD. 506, 507

188 JADE COMP.PROD. 508

189 JAMECO ELECTR. 516, 517

190 JDR MICRODEVICES 522, 523

191 JIM-PAK 497

192 KADAK PRODUCTS 196

• KENGORE CORP. 496421 KRAMER SYS.INT'L 399

193 KV 33 494

194 L & S 502

195 LABORATORY MICROSYS. 496

196 LEADING EDGE PROD Clll

197 LEAPAC SERVICES 358

198 LIFEBOAT ASSOC. 213

199 LIFEBOAT ASSOC. 341

200 LIFEBOAT ASSOC. 361

201 LNW RESEARCH 285

202 LOGICAL DEVICES 492

203 LOGO COMP.SYS. 365

204 LOMAS DATA PRODUCTS 441

205 LYBEN COMP.SYS. 498

206 MACROTRONICS 492

207 MACROTRONICS 502

208 MAGNOLIA MICROSYS. 469

209 MALIBU ELECTR. CORP. 215

210 MARKETLINESYS INC390

211 MARTEC 373

212 MARYMAC INDUSTRIES 112

213 MASTER ELECTR.INC. 238

214 MAXELL DATA PRODUCTS 287

• MCGRAW-HILL BOOK CO. 225

• MCGRAW-HILL BOOK CO. 268

• MCGRAW-HILL BOOK CO. 465

215 MEADE'S DATA SYS. 500

216 MEAS.SYS. & CONTROLS 29

• MEAS.SYS. & CONTROLS 31

• MEDIAMIX98

217 MENTOR SOFTWARE 494

218 MERRIMACK SYSTEMS 260

219 META TECHNOLOGIES 470

220 MICRO AGE COMP.STORE 169

221 MICRO BUSN. ASSOC. 373

• MICRO BUSN. WORLD 295

222 MICRO COM 353

• MICRO COMP.DISC.CO. 426

223 MICRO COMP.DISTR. 394

224 MICRO DATA BASE SYS 109

225 MICRO FOCUS 97

226 MICRO HOUSE 73

227 MICRO MANAGEMENT SYS. 449428 MICRO MINT 107

228 MICRO PRO INT'L. 241

229 MICRO WORKS, THE 212

230 MICROACE 461

231 MICROCOMP.TECH.INC. 313

232 MICROCOMPUTER APP. 388

233 MICROCRAFT SYS 298

234 MICROMAIL218

235 MICROMATE ELECTR.INC. 432

• MICROPERIPH.CORP.THE 500

236 MICROSETTE INC. 232

237 MICROSOFT (CPD) 191

238 MICROSOFT (CPD) 199

239 MICROSTUF.INC. 18

240 MICROTAX 216

241 MICROTECH EXPORTS 397

242 MIDDLETON.WILSON 500

243 MIKOS 488

244 MILLER MICROCOMP.SERV. 415

245 MIN MICROCOMP SFTW 111

246 MINI COMP.SUPPLIERS 374

To get further information on the products advertising in BYTE, fill out the reader service card withyour name and address. Then circle the appropriate numbers for the advertisers you select from thelist. Add an 18<ent stamp to the card, then drop it in the mail. Not only do you gain information, butour advertisers are encouraged to use the marketplace provided by BYTE. This helps us bring you a big-ger BYTE. The index is provided as an additional service by the publisher, who assumes no liability forerrors or omissions. 'Correspond directly with company.

Inquiry No.

Page No.

247 MINI MICRO MART 499

249 MORROW DESIGNS 184, 185

250 MOUNTAIN COMPUTER 19

251 MOUNTAIN VIEW PRESS 229

252 MPI 267

253 MSD 380

254 MT MICROSYSTEMS 80

255 MT MICROSYSTEMS 81

256 MTI 425

257 MULTI BUSN.COMP.INC. 414

258 MUSE COMPANY 362

259 NAT'L.DATA SUPPLIES 492

260 NATIONAL TRICOR 422

261 NEBS 344

262 NEC AMERICA 95

263 NEECO 227

264 NET PROFIT COMP. 90

• NETRONICS 228, 230, 346

266 NORTH AMER TECH 82

267 NORTH AMER TECH 116

268 NORTH STAR COMPUTERS 105

269 NORTHWEST INSTR.SYS. 438

270 NOVATION 245422 NOVELL 339

• NRI SCHOOLS ELECTR.DIV. 305

• OASIS SYSTEMS 418

271 OHIO SCIENTIFIC INSTR. C IV

272 OKIDATA CORP. 205

273 OLYMPIC SALES 451

276 OMEGA MICROWARE.INC. 444275 OMEGA SALES 322, 323

277 OMNI RESOURCES 85

278 OMNITEC DATA 377

279 ORACLE ELECTR. 504

280 ORANGE MICRO 157

281 ORANGE MICRO 279

282 ORION INSTRUMENTS 492

283 ORTHOCODE GROUP 408

284 OSBORNE COMPUTERS 33

285 OSBORNE/MCGRAW-HILL 76, 77

• OWENS ASSOC. 138, 139

286 PACIFIC COMP BRK. 198

287 PACIFIC EXCHANGES 396

288 PACIFIC EXCHANGES 492

289 PACIFIC EXCHANGES 496

290 PACIFIC EXCHANGES 498

291 PAGE DIGITAL 512, 513

292 PALOMAR COMP.EQUIP. 247

293 PAN AMERICAN ELEC INC. 258

294 PASSWORD DISTR. 311

295 PCD SYSTEMS INC. 24

296 PEACHTREE SOFTWARE 190

• PERCOM DATA 7, 14, 15

297 PERSONAL COMPUTERS 423406 PHASE ONE SYS.INC. 329

298 PICKLES & TROUT 366

299 PKAY CORP. 500

300 POLY PAKS 494

• POPULAR COMPUTING 240

301 POWER ONE INC. 179

302 PRIME SOURCE 133

303 PRIME SOURCE 141

304 PRIME SOURCE 197417 PRIORITY ONE 487

305 PRIORITY ONE 518, 519

306 PRIORITY ONE 520, 521

307 PROGRAMMERS SFTW EX. 498411 PROGRAMS ULTD 186

308 PROTECTO ENTERPR. 498

309 PURCHASING AGENTJHE 78

310 QUALITY COMP.PARTS 492

311 QUALITY SOFTWARE 340

312 QUALITY SOFTWARE 387

313 QUASAR DATA PROD.INC. 221

314 QUAY CORP 309

315 QUEST ELECTR. 501

316 R.C.ELECTRONICS 96

317 R.R.SOFTWARE 338

318 RACET COMPUTES 320

319 RADIO SHACK 57

320 RADIO SHACK-GLNW.SPR. 368

321 RADIO SHCK FRNCJ7079 192' RANDOM HOUSE 411

322 RCA 48

323 RCE ELECTR. 490

324 ROBOTICS AGE 369

325 S C DIGITAL 396

429 S & M SYSTEMS 399

326 S-100 INC 388

327 SCIENTIFIC SFTW.PROD 494

328 SCION CORP 5

329 SCITRONICS 410

• SCOTTSDALE SYSTEMS 30

330 SCR ELECTR. 260

430 SEABIRD PRESS, THE 504

331 SEATTLE COMP PRODS 349

332 SELECT INFO SYS. 325404 SGL WABER 502

334 SHOPSMITH 359

335 SIERRA DATA SCIENCES 410

336 SIRIUS SOFTWARE 500

337 SLUDER 500

341 SOFTECH MICROSYS 333

342 SOFTWARE HOWS 113

343 SOFTWARE PROD.INT'L. 201

333 SFTW TECH FOR COMP. 251

October 1981 © BYTE Publications Inc

527

Reader Service.

Inquiry No.

Page No.

344345346347348408350400351

352353

354355356

SOLID STATE SALES 401SORCIM 135

SORRENTO VALLEY ASSOC 343SPECIALIZED BUSN SYS 178SPECTRUM SOFTWARE 319SSM MICRO COMP PROD 11STATCOM CORP. 71STATIC MEMORY SYS 211STELLAR SYSTEMS 226STRUCTURED SYS.GRP. 35SUNNY INT'L. 475SUPERSOFT83, 93SUPERSOFT 131SYBEX 209

SYNCHRO SOUND 136SYNCTRONICS52SYS.INTERFACE CONS. 182SYSTEMS PLUS 321

Inquiry No.

Page No.

357358359

360361362363364365

338339340

368369

SZ SOFTWARE SYSTEMS 469TARBELL ELECTR. 273TECH.MICRO SYS. 500TECHNICAL SYS CONS 21TECMAR INC 357TEI.INC 59TEI.INC 207TELEVIDEO INC 183TERMINAL DATA SYS. 498TEXAS COMP.SYS. 379TEXAS INSTRUMENTS 65THUNDERWARE 291TIMEMNGMNT. SFTW. 23TIMEMNGMNT. SFTW. 127TIMEMNGMNT. SFTW. 231TINNEY.RBT.GRAPHICS 456TNW CORP. 392TRAK CO..THE 173

Inquiry No.

Page No.

370 TRANSNET CORP. 368

371 TRANSWAVE CORP. 177403 TRINITY GROUP 492

372 TSD DISPLAY PROD. 22

373 TSE/HARDSIDE 405

374 U.S. MICRO SALES 351

375 U.S. MICRO SALES 477

376 U.S. ROBOTICS 367

• UNITED SFTW OF AM 299

377 UNIVERSAL SFTW.DIRCT. 412

378 UNIVERSAL SFTW.STUDIOS 454

379 UVEON COMP.SYS. 79

380 VAN HORN OFFICE SUPP. 395

382 VANGUARD SYS.GRP. 75

383 VECTOR ELECTR. 446

384 VECTOR GRAPHICS 87

* VERTICAL DATA SYS.INC. 94

385 VIDEX269

Inquiry No.

Page No.

386389

401

390391

409392366393394395396397

VISIBLE COMP.SUPPLY 280

VISTA COMPUTER CO 193

VOTRAX 194

VR DATA 442

WASHINGTON COMP.SERV. 489

WESTERN WARES 504

WESTICO INC. 115, 498

WESTWARE 223

WHITESMITHS LTD 99

WICAT 25

WILD HARE COMP.SYS. 189

WINCHENDON GRPJHE 504

WINTEK CORP. 469

WINTERHALTER & ASSOC. 360

WW COMPONENT SUPPLY 505

X COMP 243

ZENRAD CONTROLS 498

ZOBEX 151

BOMB

)naoina Monit

or Box

Author(s)

BYTE'

sC

Article #

Page

Article

I

26

The IBM Personal Computer: First

Impressions

Lemmons

2

36

Build an Intelligent EPROM

Programmer

Ciarcia

3

50

Ultra-Low-Cost Network for Personal

Computers

Clements,Daugherty

4

70

The Atari Tutorial, Part 2: Graphics

Indirection

Crawford

5

86

Atari's Telelink 1

Flint

6

92

Local-Area Networks, Possibilities for

Personal Computers

Saal

7

114

Prepare Your Program for Publication

Johnson

8

126

Software Protection in the United

Kingdom

Hayman

9

140

Network Tools, Ideas for Intelligent

Network Software

Reintjes

10

176

A Simple Implementation of

Multitasking

Brown

11

195

Tree Searching, Part 2: Heuristic

Techniques

Williams

12

214

Drawing with UCSD Pascal and the

Hiplot Plotter

Stork

13

250

Evaluate Your Home's EnergyEfficiency, Conserve Energy with Your

Computer

Beasley

14

264

Bridging the 10-Percent Gap

Brady

15

284

Graphics Fundamentals

Sandifur

16

378

Integral Data's Paper Tiger 460

Willner

17

383

The Mauro Proac Plotter

Dahmke

18

385

The Radio Shack FORTRAN Package

Daneluik

19

400

Build a Versatile Keyboard Interface for

theS-100

Richards

20

407

PERT Organization

Maurer

21

413

Should the DO Loop Become an

Assembly-Language Construct?

Williams

22

430

Multiple Regression for the TRS-80

Madron

23

448

Bits and Bytes in Pascal, And Other

Binary Wonders

Casseres

24

458

Apple Analog-to-Digital Conversion in

27 Microseconds

Seeds

25

462

PS—A FORTH-Like Threaded Language,

Part 1

Motalygo

July Bomb Results:Ciarcia and the Sun

It came as no surprise to us thatSteve Ciarcia's article, "Build aZ8-Based Control Computer withBASIC, Part I," finished first in theJuly BOMB competition. Steve'slatest technological breakthroughhas prompted numerous com-ments and inquiries, both to himand to BYTE. He will receive theSI00 first prize.

Second place for July went toGeorge E Mobus for his article,"Harvesting the Sun's Energy."George will receive S50 for hisdescription of a computer modelthat determines the amount ofsolar energy received by a flatplatecollector.

"Multiprocessing with Motorola'sMC6809E," by Hunter Scales, tookthird place. He showed how to im-plement a multiprocessor environ-ment using the new MC6809E.

528 October 1981 © BYTE Publications Inc

WORDSWORTH,TAKE A LETTER:

THE FIRST SUPER-SIMPLE LETTER QUALITY WORD PROCESSOR

IN THE WORLD THAT CAN SIT NEXT TO YOUR SECRETARY-

FOR LESS THAN $5,000.

"Wordsworth™" removes thefear and loathing many people haveabout things called "computers"and "word processing." BecauseWordsworth just sits at a desk anddoes what he's told. With unique new,simplified software, it can tell itstypist what to do—step by simplestep—to perform even the mostcomplicated tasks.

It can not only "take a letter,"but it can revise it, customize it in mil-lions of ways (quite literally), person-alize it, print it on your letterhead orbusiness form so you can't tell it fromhand-typed ... in short, everythingbut put it in an envelope.

Moreover, it can perform allsorts of mundane business functions,

like general ledgers and accountingreports, using easily availableindustry-compatible CP/M™ software.

Installation? Plug it in. (Cablesupplied.)

Size? Bigger than a breadbox—but not by much. It's about half as big,or less, than systems that can't do halfas much. Definitely desktop—a sub-compact 20" by 40".

Service? Available everywhere.

Price? About $4,995. Completeand ready to go.

For the name of your nearestdealer—and a free hands-ondemonstration—just pick up thenearest telephone.

TOLL-FREE 1-800-343-6633.

In Massachusetts, call collect (S17) 828-815a Telex 951-624.

LEADINGEDGE.

Leading Edge Products, Inc., 225 Turnpike Street, Canton, Massachusetts 02021DEALERS: For immediate delivery from the Leading Edge Inventory Bank™ on "Wordsworth" and other of the

industry's most popular products, just give us a call.

Circle 196 on inquiry card.

"Over 15,000 items in inventory could bea nightmare. But it's not 'cause myChallenger ^^computer workslike a I**3 dream*"

"My fastener business isgrowing rapidly. I have over800 customers utilizing my15,000 inventory items daily.Keeping track of inventory,orders, and receivables atthis volume level could bea nightmare. But it's not'cause my Challenger computer works like a dream.Terrific, Ohio Scientific!"

Richard Nolan, President,Aerospace Nylok Corp.,Hawthorne, New Jersey

Ohio Scientific was first to add Winchester

hard disk drives to microcomputers. This

advanced technology allows low cost

microcomputers to store over 100 times

as much information on line as they

could before.

"With our Challenger computer we've developedsophisticated real estate programs and informationfiles that give our customers and our salesassociates that extra edge in fast, accurate realestate market information analysis and forecasting.We now have a strong managerial accounting andmarket information system as well as word process-ing at an affordable cost. Terrific, Ohio Scientific!"

Charles Smith, Jr., President, Montague, Miller & Co., RealtorCharlottesville, Virginia

OHIO SCIENTIFIC HARD DISK BASED

MICROCOMPUTERS START AT LESS THAN $10,000

AND ARE SOLD BY MORE THAN 400 DEALERS

NATIONWIDE. FOR THE ONE NEAREST YOU,

CALL 1-800-321-6850 TOLL FREE.

&fr\

"I'm a fuel oil jobber,and I can't believe howreliable my Challengerhas been, with all ithas to keep track of.But, it's been doing itfor two years now, andthat's terrific, OhioScientific!"

Wade Carlson,Vice President,Wally Carlson & Sons,Lindstrom, Minnesota

a jyfcw¥l Company

333 SOUTH CHILLICOTHE ROAD

AURORA, OH 44202 • [21 6] 831 -5600

Circle 271 on inquiry card.