Byte Magazine Volume 05 Number 05 - Floppy Disks

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*7fc*t& BIG

State of the art "Winchester"type hard disk with a datastorage capacity of nearly 16 Megabytes, makes theSWTPC 6809 system the most flexible as well as the mostpowerful eight-bit microcomputer system in the world.The intelligent controller, using DMA data transfer, makesmaximum use of the "Winchester" capability. It is com-pletely compatible with the FLEX9 operating system usedon the SWTPC 6809 floppy disk system.

CDS-1 "Winchester" disk drive with controller. .$3,995.00Cabinet—matching our 6809 computer desk . . . $150.00

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219 W. RHAPSODY

SAN ANTONIO, TEXAS 78216 (512) 344-0241

Circle 325 on inquiry card.

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A

C Cromemeo

Low-cos

IrcTEii

isk computers

11 megabytes of hard disk and 64 kilobytes of fast RAM in a

Z80A computer for under $10K. Two floppy drives, too.

Naturally, it's from Cromemeo.

It's a reality. In Cromemco's newModel Z-2H you get all of the aboveand even more. With Cromemeo youget it all.

In this new Model Z-2H you getnot only a large-storage Winchesterhard disk drive but also two floppydisk drives. In the hard disk drive youget unprecedented storage capacityat this price—11 megabytes unfor-matted.

You get speed—both in the 4 MHzZ80A microprocessor and in the fast64K RAM which has a chip accesstime of only 150 nanoseconds. Youget speed in the computer minimuminstruction execution time of 1 micro-second. You get speed in the harddisk transfer rate of 5.6 megabits/sec.

EXPANDABILITY

You get expandability, too. Thehigh-speed RAM can be expanded to512 kilobytes if you wish.

And the computer has a full 12-slotcard cage you can use for additionalRAM and interface cards.

BROADEST SOFTWARE SUPPORT

With the Z-2H you also get thebroadest software support in the

microcomputer field. Software Cro-memeo is known for. Software likethis:

• Extended BASIC

• FORTRAN IV

• RATFOR (RATional FORtran)

• COBOL

• Z80 Macro Assembler

• Word Processing System

• Data Base Management

with more coming all the time.

SMALL, RUGGED, RELIABLE

With all its features the new Z-2H,including its hard disk drive, is stillhoused in just one compact cabinet.

Hard disk drive at lower left can be inter-changed just by sliding out and disconnectingplug. Seven free card slots are available.Z-2H includes printer interface card.

Circle 1 on Inquiry card.

Q

Included in that cabinet, too, isCromemeo ruggedness and reliability.Cromemeo is time-proved. Ourequipment is a survey winner forreliability. Of course, there's Cro-memco's all-metal cabinet. Rugged,solid. And, there's the heavy-dutypower supply (30A @ 8V, 15A @+ 18 V, and 15A @ -18V) for cir-cuitry you'll sooner or later want toplug into those free card slots.

SEE IT NOW

Last summer we told you this newZ-2H would be a smash. And it is.So see it at your dealer's now. Havehim put you in touch with a user—there are lots of them becauseCromemeo has been delivering formonths. See for yourself how pleasedour users are.

PRESENT CROMEMCO USERS

We've kept you in mind, too. Askabout the new Model HDD DiskDrive which can combine with yourpresent Cromemeo computer to giveyou up to 22 megabytes of diskstorage.

Cromemeo

Incorporated280 BERNARDO AVE., MOUNTAIN VIEW, CA 94040

Tomorrow's computers today

(415)964-7400

LatchedOutput:

4 MHzCrystal Clock

On Card

VoltageRegulation

Parallel

Parallel

I/O Port #1

I/O Port #2

\

/

ParallelI/O Port #3

\

RS-232 orCurrent LoopI/O Port #4

/

8KR0MCapacity

IK RAM

Standard Bus

for System

Expandability

ProgrammableBaud RateUART with

Interval Timers

4 MHz Z-80A

Completely BufferedBus Interface

The single card computer

with the featuresthat help you in real life

COMPLETE COMPUTER

In this advanced card you get a pro-fessional quality computer that meetstoday's engineering needs. And it's onethat's complete. It lets you be up andrunning fast. All you need is a powersupply and your ROM software.

The computer itself is super. Fast4 MHz operation. Capacity for 8K bytesof ROM (uses 2716 PROMs which canbe programmed by our new 32K BYTE-SAVER® PROM card). There's also 1K ofon-board static RAM. Further, you getstraightforward interfacing through anRS-232 serial interface with ultra-fastspeed of up to 76,800 baud — softwareprogrammable.

Other features include 24 bits of bi-directional parallel I/O and five on-board programmable timers.

Add to that vectored interrupts.

ENORMOUS EXPANDABILITY

Besides all these features the Cro-memco single card computer gives youenormous expandability if you ever needit. And it's easy to expand. First, youcan expand with the new Cromemco32K BYTESAVER PROM card mentionedabove. Then there's Cromemco's broadline of S100-bus-compatibie memoryand I/O interface cards. Cards with fea-tures such as relay interface, analoginterface, graphics interface, opto-isolator input, and A/D and D/A con-version. RAM and ROM cards, too.

I

* > i ■ i

Card Cage 32K BYTESAVER PROM card

Q

EASY TO USE

Another convenience that makes theModel SCC computer easy to use is ourZ-80 monitor and 3K Control BASIC (intwo ROMs). With this optional softwareyou're ready to go. The monitor givesyou 12 commands. The BASIC, with 36commands/functions, will directly ac-cess I/O ports and memory locations —and call machine language subroutines.

Finally, to simplify things to the ulti-mate, we even have convenient cardcages. Rugged card cages. They holdcards firmly. No jiggling out of sockets.

AVAILABLE NOW/LOW PRICE

The Model SCC is available now at alow price of only $450 burned-in andtested (32K BYTESAVER only $295).

So act today. Cet this high-capabilitycomputer working for you right away.

Cromemco

incorporatedSpecialists in computers and peripherals280 BERNARDO AVE., MOUNTAIN VIEW, CA 94040 « (415) 964-7400

2 BYTE May 1980

Circle 1 on Inquiry card.

page 22

ON LASTMONTH'S COVER

The April cover, which hasreceived so many compliments,was a creation of the photo-graphic artistry of Ed Crabtree.Ed is a professional commercialphotographer in Peterborough,N H and has been BYTE'sphotographer from day one.This was Ed's first BYTE cover.We're sure it won't be his last.

In The Queue

EITE May 1980Volume 5, Number 5

Foreground

20 A DC-TO-DC CONVERTER by Michael PiccoHere's a simple converter that uses a standard integrated circuit for producing a 25 mA bipolarsource from a single-ended power supply.

22 I/O EXPANSION FOR THE RADIO SHACK TRS-80, Part 1: Principles ofParallel Ports by Steve Ciarcia

This month Steve explains the operation of parallel input/output as a prelude to next month'sdesign for an economical RS-232C interface.

44 KIMDOS, Using Your KIM-1 with a Percom Floppy-Disk Drive by Joel SwankUsing the LFD-400 disk-controller board, the KIM-1 can access up to 87.5 K data bytes on several5-inch hard-sectored floppy-disk drives.

72 INTERFACE A FLOPPY-DISK DRIVE TO AN 8080A-BASED COMPUTER

by John Hoeppner

Building a disk-controller board for a Shugart SA400 disk drive can be done easily and with com-monly available parts.

196 GIVE YOUR COMPUTER AN EAR FOR NAMES by Tom MunneckeWith the Soundex code, you can locate people's names in your data base by similar, but not ex-act, spellings.

214 THE COSMAC DOODLER by Jeff Duntemann

An electronic sketchpad? Even a small system like the COSMAC ELF can draw designs using a

video display.

250 ERROR CHECKING AND CORRECTING FOR YOUR COMPUTER

by Gregory J Walker

Storage devices can introduce data errors. The system presented here can increase reliability and

speed of these peripherals.

Background

12 THE CASSETTE LIVES ON, An Alternative to Hoppy-Disk Mass Storage

by Emory Cook

Floppy disks may be the glamorous way to store programs and data, but the cassette is far from

obsolete.

104 A GRAPHICS TEXT EDITOR FOR MUSIC, Part 2: Algorithms

by Randolph Nelson

The conclusion of this article sets forth the routines to create and use the various arrays described

in part 1.

120 USING THE COMPUTER AS A MUSICIAN'S AMANUENSIS, Part 2: Goingfrom Keyboard to Printed Score by Jef Raskin

Part 2 continues the examination of the subtle problems encountered when translating informationfrom performance to written score.

130 COMPARING FLOPPY-DISK DRIVES BY SOFTWARE SIMULATION

by Dennis Nendza

Now you can get some idea of the relative performance of different units by simulating their

mechanical functions in a BASIC program.

202 THE CLUB COMPUTER NETWORK by Joe Kasser

If your club is considering to form a program- and data-exchange network, the telephone and

amateur radio links described here will be a valuable source of ideas.

Nucleus

8144152

190

Editorial: Computer-Controlled

Viewing of the 1980 Eclipse

Letters

BYTELINES (formerly BYTE News)

Technical Forum: Simplifying the

Curve-Plotting Calculation by

Geometric Means; Alpha Locking in

Software; Maintaining a Single Exit

Point

Programming Quickies: Decisions,

Decisions; Formatted Program Out-

put for the KIM-1

226 Book Reviews

230 Clubs and Newsletters

234 BYTE's Bits

236 BYTE's Bugs

238 Event Queue

280 NCC Information

286 What's New7

335 Unclassified Ads, BOMB Results

336 Reader Service, BOMB

May 1980 © BYTE Publications Inc

Publishers

Virginia Londoner, Gordon R WilliamsonAssociate PublisherJohn E HayesAssistant

Cheryl A Hurd

Editorial Director

Carl T Helmers Jr

Editor-in-Chief

Christopher P Morgan

Book Editor

Bruce A Roberts

Editors

Richard S Shuford, Gregg Williams,

Curtis P Feigel

Chief Copy Editor

David William Hayward

Copy Editors

Faith Hanson, Warren Williamson,

Robin M Moss, Anthony J Lockwood

Assistant to the Editors

Faith Ferry

Assistant

Debe Wheeler

New Products Editor

Clubs, Newsletters

Charles Freiberg

Drafting

Jon Swanson

Production Director

Nancy EstleProduction Art

Wai Chiu Li, Christine Dixon,

Holly Carmen LaBossiere, Deborah Porter

Typographers

Sherry McCarthy, Debi Fredericks,

Donna Sweeney

Advertising Director

Thomas HarveyAssistants

Ruth M Walsh, Ms. Marion Gagnon

Special Projects Coordinator

Jill ECallihanAssistantKaren A CilleyMarketing Coordinator

Laura A Hanson

Circulation Manager

Gregory Spitzfaden

Assistants

Pamela R H Spitzfaden, Agnes E Perry,

Melanie Bertoni, Barbara Varnum,

Louise Menegus

Dealer Sales

Thomas Yanni

Receptionist

Jacqueline EarnshawTraffic Department

Mark Sandagata, Rob Hannings

Controller

Daniel Rodrigues

Assistant

Mary E Fluhr

Accounts Receivable Specialist

Karen Burgess

Accounts Receivable Assistant

Jeanne Cilley

National Advertising Sales Representatives:

Hajar Associates Inc

East

280 Hillside Av, Needham Heights MA 02194

(617)444-3946

521 Fifth Av, New York NY 10017

(212) 682-5844

Midwest

2405 Lawndale

Evanston IL 60201 (312) 864-3467

West, Southwest

1000 Elwell Ct, Suite 227, Palo Alto CA 94303

(415) 964-0706/(714) 540-3554

ON THE COVER

On May's cover, Robert Tinney has formed an abstractionof the most important medium of mass storage in today's eraof small computers, the floppy disk. Heightening its shimmer-ing mystery, we find a disk wavering in the heat above somedesert landscape. To enlighten you, this issue features severalarticles that present valuable information about floppy-disktechnology. This technology is no mirage — it will even workwell in a similar, hot environment of East Africa, as theeditorial on page 6 describes.

Officers of McGraw-Hill Publications Company: Paul F. McPherson, President; Executive Vice Presidents: JamesE. Boddorf, Gene W. Simpson; Group Vice President: Daniel A. McMillan; Senior Vice President-Editorial: Ralph R.Schulz; Vice Presidents: Kemp Anderson, Business Systems Development; Stephen C. Croft, Manufacturing;Robert B. Doll, Circulation; James E. Hackett, Controller; William H. Hammond, Communications; Eric B. Herr,Planning and Development; John W. Patten, Sales; Edward E. Schirmer, International.

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

BYTE is published monthly by BYTE Publications Inc, 70 Main St, Peterborough NH 03458, a wholly-owned sub-sidiary of McGraw-Hill, Inc. Address all mail except subscriptions to above address: phone (603) 924-9281. Addresssubscriptions, change of address, USPS Form 3579, and fulfillment questions to BYTE Subscriptions, PO Box 590,Martinsville NJ 08836. Controlled circulation postage paid at Waseca, Minnesota 56093 - USPS Publication No.528890 (ISSN 0360-5280). Canadian second class registration number 9321. Subscriptions are $18 for one year, $32for two years, and $46 for three years in the USA and its possessions. In Canada and Mexico, $20 for one year, $36for two years, $52 for three years. $32 for one year air delivery to Europe. $32 surface delivery elsewhere. Air deliveryto selected areas at additional rates upon request. Single copy price is $2.50 in the USA and its possessions, $2.95in Canada and Mexico, $4.00 in Europe, and $4.50 elsewhere. Foreign subscriptions and sales should be remitted inUnited States funds drawn on a US bank. Printed in United States of America.

Address all editorial correspondence to the editor at the above address. Unacceptable manuscripts will bereturned if accompanied by sufficient first class postage. Not responsible for lost manuscripts or photos. Opinionsexpressed by the authors are not necessarily those of BYTE. Entire contents copyright © 1980 by BYTE Publica-tions Inc. All rights reserved. \t ta,

BYTE® is available in microform from University Microfilms International, 300 N Zeeb Rd, Dept PR, ^ /^^^*'Ann Arbor Ml 48106 USA or 18 Bedford Row, Dept PR, London WC1R 4EJ ENGLAND. *</MO>°

Subscription WATS Line: (800) 258-5485 *r*1^

Office hours: Mon-Thur 8:30 AM - 4:30 PM, Friday 8:30 AM - Noon, Eastern Time

May 1980 © BYTE Publications Inc

512 x 484 resolutiondisplay supervised byits own Z80 micropro-cessor

32K bytes of dual portmemory give a com-pletely undisturbedscreen imageResident software em-ulates an ASCII ter-minal and providesgraphics routines forpoint, line, region, andlight pen usage, andmore

Compatible with anyS-100 system, yet eas-ily interfaced to othercomputers

72 key keyboard withgraphics functionkeys

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Complete documenta-tion

Call or write:

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Look for

Shugart drives

in personal

computer systems

made by these

companies.

Editorial

Altos Computer Systems

2360 Bering DriveSan Jose, CA 95131

Apple Computer

10260 Bandley DriveCupertino, CA 95014

Commodore Business Machines, Inc.

3330 Scott BoulevardSanta Clara, CA 95051

Digital Microsystems Inc.

4448 Piedmont AvenueOakland, CA 94611

Industrial Micro Systems

628 N. EckhoffOrange, CA 92668

Micromotion Inc.

1620 Montgomery StreetSan Francisco, CA 94111

Morrow Designs Inc.

Thinker Toys

5221 Central Avenue

Richmond, CA 94804

North Star Computers Inc.

1440 Fourth StreetBerkeley, CA 94710

Polymorphic Systems

460 Ward Drive

Santa Barbara, CA93111

Tano Corporation

4301 Poche Court WestNew Orleans, LA 70129

Technico Inc.

9051 Red Branch RoadColumbia, MD 21045

Texas Electronic Instruments

5075 S. Loop EastHouston, TX 77033

Vista Computer Company

1401 E. BorchardSanta Ana, CA 92705

Shugart

Computer-Controlled Viewingof the 1980 Eclipse

by Carl Helmers

As noted in the March 1980 editorial, I traveled to Kenya in East Africa toobserve the 1980 total solar eclipse with an Apple II Pascal system controllingthe photographing of the event. This month's editorial is a commentary aboutthe experience. This commentary was written upon my return to New Hamp-shire a week after the eclipse.

The final preprations for the Kenya eclipse of 1980 were made in an inten-sive session of 24-hour workdays, February 2, 3, 4, and 5. One physiologicalconsequence of no sleep for 3 or 4 days is that when traveling through 8time zones there is no possibility for jet lag! One's body is so tired that allmemory of the previous time zone is erased completely. Norm Whyte andLaurel Allen, who coordinated many of the details of the trip to Kenya, arri-ved in Boston from California on the second of February and spent theweekend at my home. During this final weekend's activity, we each hadseveral chores to finish. One detail, for example, was making sure that bothcomputers would operate simultaneously off Norm's portable Honda ACgenerator. Another was adding a hardwood extension to Norm's telescopemount so that my camera could be attached along with his.

In connection with the program design of my experiment, a number ofcrucial points had to be verified. With the time allocation procedures com-pleted as described in the March 1980 editorial, writing the real-time pro-cedures to execute the time line proved trivial. These were the procedures leftin dummy form in the listing 1 published with the March 1980 editorial. Inlisting 1 accompanying this editorial, readers will find the final form of theprogram I used. In approaching this final form I implemented the executionroutines using a module named "milli" to carry out time delays of an integernumber of milliseconds. The program itself was verified by driving the camerainterface using a first approximation to "milli" in the form of Pascal dummyloops used to count time.

Originally I hoped that (by fortuitous circumstance) I could use some com-bination of Pascal statements in a loop to provide time delays in units ofmilliseconds. But, after perhaps an hour of fooling with various combinations,I came to the conclusion that this would not be possible. I was either 6% tooslow or 6 % too fast depending on whether or not I put a unary negation in atiming loop's dummy assignment statement.

Since program development time was limited by a departure schedule, itsoon became apparent that the lesser of two evils (imprecision or assemblylanguage) was to write an assembly-language routine called "milli" that linksto Pascal with a single integer parameter specifying a loop delay time inmilliseconds. I finished this necessary step sometime in the wee hours ofFebruary 4. I checked the accuracy with various simple test programs writtenin Pascal. Of course, my timing assumption was that zero time would be spentoutside of "milli" executing the Pascal code of the actual program. Thisassumption was verified with test runs of the whole eclipse photography se-quence, which showed about 1% error. By adjusting the constants in the delayroutine slightly, this error was compensated at the gross level of the entireeclipse sequence's 241-second execution time.

Text continued on page 52

6 May 1980 © BYTE Publications Inc

"]% Shugartbllowed me h

At4"

&Sfts;

.

v

"After working all day with the computer atwork, it's a kick to get down to Basic at home. Andone thing that makes it more fun is my Shugartminifloppy™' We use Shugart drives at work, sowhen I bought my own system I made sure it had aminifloppy drive.

"Why? Shugart invented the minifloppy. Theguys who designed our system at work tell me thatShugart is the leader in floppy design and hasmore drives in use than any other manufacturer. IfShugart drives are reliable enough for hard-workingbusiness computers, they've got to be a goodvalue for my home system.

"When I'm working on my programs late atnight, I can't wait for cassette storage. Myminifloppy gives me fast random access and data

■

I H

transfer. The little minidiskettes™ store plenty ofdata and file easily too.

"I made the right decision when I bought asystem with the minifloppy. When you lay out yourown hard-earned cash, you want reliability andperformance. Do what I did. Get a system with theminifloppy."

If it isn't Shugart,it isn't minifloppy.

^Shugart

435 Oakmead Parkway, Sunnyvale, California 94086

See opposite page for list of manufacturers featuring Shugart's minifloppy in their systems.

TM minifloppy is a registered trademark of Shugart Associates

Letters

Information onPotter Printer Needed

Can a reader of BYTE help me? Irecently purchased a printer fromsalvage, and I hoped to obtaindocumentation and a schematic diagramfrom the manufacturer.

The printer is a Potter ModelLP-3000, manufactured by the Potter In-strument Company, formerly of Plain-ville, New York. I called the firm, and Iwas told:

1) The company is in the process ofmoving to New Hampshire.

2) This particular model of printer is ob-solete.

3) They have no documentation orschematic for this model.

From my examination of the circuitsand machinery, I believe the PotterLP-3000 is a daisy-wheel type with aserial data input. However, whether ituses ASCII or not, I can't tell.

Can someone tell me how I can inter-

face this printer to my Radio ShackTRS-80 Model I Level II computer withexpansion interface?

Nick Tountas838 Juniper RdGlenview IL 60025

Questioning "Affordable"!

When you are on Social Security, anaffordable computer system that costs$6000 is like "# @ * "I When yourmonthly income is $360, to have aneditor smugly talk of plunking down$6000 cash as if it were a minor outlaytends to be very irritating.

On top of that, the system MrHelmers described is just the sort (withminor modifications) I have wanted forages. Another thing that hurts is theindustry-wide disinclination to even con-sider time payments or credit. I knowthat I'll have to wait, and probably waitover 5 years, but maybe not. If I werejust disgusted with your editorial, Iwouldn't have bothered to write. What I

Now MONTY™ challenges you to

SCRABBLE'

MONTY™'s no ordinary Scrabble* player! He spices up his game with music andcolorful graphics. And he can challenge you at any skill level- beginner to expert withtens of thousands of words. Available on disk only for Apple II, TRS-80 LEVEL II andCP/M based systems (16K required) for use with your Scrabble game. Send $29.95check or money order or CALL NOW Toll Free (see below) for VISA or MASTER-CHARGE purchase, lowans add sales tax." MONTY™ plays Monopoly'also available.

Another IncredibleComputer OpponentProgram

Ritam CorporationP.O. Box 921

Fairfield, Iowa 52556 |

"MONTY" plays Scrabble"I □ Apple II disk $29.95

□ TRS-80 Level II disk 29.95

'Scrabble Is a trademark of Selchow & Rlghter Co.Monopoly Is a trademark of Parker Bros., Inc.Apple Is a trademark of Apple Computer, Inc.TRS-80 Is a trademark of Tandy Corp.CP/M Is a trademark of Digital Research Inc.MONTY" Is not sponsored or endorsed bySelchow & Rlghter Co. or Parker Bros.. Inc.'Rltam Corp. 1980

□ CP/M5"disk

□ CP/M8"disk

29.9529.95

"MONTY1" plays Monopoly'

□ Apple II cassette $24.95D Apple II disk 27.95

□ TRS-80 cassette 24.95

□ TRS-80 disk 27.95

Charge my D VISA □ MASTERCHARGE Exp. Date..

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Address

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ORDER NOW TOLL FREE • 800-624-7888 • 800-852-7777 (Calif.) • 800-824-7919 (HI & AL) Ask for Operator 975.

would like to know is if any BYTEreader knows of a way I can obtain sucha system as Mr Helmers described —perhaps secondhand — without payingthousands of dollars cash7 By squeezing,I can afford $100 a month now, and byJuly I should be able to afford $150 amonth, perhaps more.

In a way, I have to thank Mr Helmersfor that editorial. It made me madenough to write, and perhaps there is asolution to my problem.

Fred J Remus Jr

POB 2453

San Diego CA 92112

Carl Helmers Replies

Give the industry time. Five yearsago, the same system might have beenwell in excess of $30,000, with inferiorprogramming languages and comparableon-line storage capacity. Tremendousstrides have been made in the past 5years, and we can expect a certainleveling-off of prices in the future asmass production at 100,000 unit levelsper year starts becoming reality. Andthen, of course, one looks at it from thepoint of view of increasing demand forthese products. If we do not write aboutthe conception of a good machine, wehave no interest on the part ofusers.... CH

Gomoku

I was interested in the "ProgrammingQuickie" by John Allwork ("BASICGame: GOBANG," November 1979BYTE, page 56) for Gobang is also call-ed "Gomoku." There has been a com-petition running for Gomoku programssince 1975; I am the current champion.People interested in the contest shouldcontact:

Shem Wang

Dept of Computer and Information

ScienceUniversity of GuelphGuelph, Ontario, CANADA

So far my different programs have runon large mainframe computers, but Ihope to have one working on my NorthStar microcomputer for the next roundof competition.

Mike Compton196 Metcalfe St, Apt 810Ottawa, OntarioK2P 1P8 CANADA

8 May 1980 © BYTE Publications Inc

Circle 2 on inquiry card.

At Intersystems,"dump" is an instruction.

Not a way of life.

(O5 when you're ready for IEEE S-100, will yourcomputer be ready for you?]

We're about to be gadflies again.

While everyone's been busytrying to convince you that largebuses housed in strong metalboxes will guarantee versatilityand ward off obsolescence, we'vebeen busy with something better.Solving the real problem with thefirst line of computer productsbuilt from the ground up to con-form to the new IEEE S-100 BusStandard. Offering you extra ver-satility in 8-bit applications today.And a full 16 bits tomorrow.

We call our new line SeriesII™ And even if you don't need thefull 24-bit address for up to 16megabytes (!) of memory rightnow, they're something to thinkabout. Because of all the perform-

ance, flexibility and economythey offer. Whether you're lookingat a new mainframe, expandingyour present one or upgradingyour system with an eye to thefuture. (Series II boards are com-patible with most existing S-100systems and all IEEE S-100 Stan-dard cards as other manufacturersget around to building them.)

Consider some of the fea-tures: Reliable operation to 4MHzand beyond. Full compatibilitywith 8- and 16-bit CPUs, pe-ripherals and other devices. Eightlevels of prioritized interrupts. Upto 16 individually-addressableDMA devices, with IEEE Standardoverlapped operation. User-selec-table functions addressed by DIP-switch or jumpers, eliminating sol-dering. And that's just for openers.

The best part is that all thisheady stuff is available nowl Inour advanced processor —a fullIEEE Bus Master featuring MemoryMap™ addressing to a full mega-byte. Our fast, flexible 16K StaticRAM and 64K Dynamic RAMboards. An incredibly versatile and

economical 2-serial, 4-parallelMultiple I/O board. 8-bit A/D-D/Aconverter. Our Double-DensityHigh-Speed Disk Controller. Andwhat is undoubtedly the most flex-ible front panel in the business.Everything you need for a com-plete IEEE S-100 system. Availableseparately, or all together in ournew DPS-1 Mainframe!

Whatever your needs, whydump your money into obsoleteproducts labelled "IEEE timingcompatible" or other words peo-ple use to make up for a lack ofproduct. See the future now, atyour Intersystems dealer or call/write for our new catalog. We'lltell you all about Series II and thenew IEEE S-100 Bus we helpedpioneer. Because it doesn't makesense to buy yesterday's productswhen tomorrow's are already here.

DnDta%v^fcDDDS'

Ithaca Intersystems Inc.,

1650 Hanshaw Road/P.O. Box 91,

Ithaca, NY 14850

607-257-0190/TWX: 510 255 4346

Searching forFORTRAN Compiler

I am an avid reader of BYTE and Ibelieve that one of my fellow readersmay be able to help me with a problem.

My school is thinking about expand-ing the courses that are offered in thearea of computer science. It is hopedthat an extensive course in FORTRANprogramming may be offered.

Our computer is a CIP/2200 manufac-tured by the Cincinnati Milacron Cor-poration. It has a small disk-operatingsystem and a card reader. The word sizeis 32 bits, and, at this point in time, thememory size is 32 K bytes. There areplans, however, to expand the memoryto 64 K bytes by the time the FOR-TRAN course is offered.

My problem i. that the CincinnatiMilacron Corporation does not make aFORTRAN compiler for our machine. Iwould like to know if any reader ofBYTE could suggest any companies thatmight sell a compiler that is compatiblewith our machine.

Daniell B McCormickBox 675

Presbyterian CollegeClinton SC 29325

Seeking Computers for the Blind

Does any reader of BYTE know of asource for a computer system that usesaudible output instead of charactersdisplayed on a terminal for itscustomary interaction with the user,such as that produced by the Votraxspeech interface? Such a computersystem would be used by blind people.It would be desirable if a BASIC inter-preter that used audible output were in-cluded .

If anyone has or knows of such asystem, please contact me.

Walter F Keleher56 Robin StRochester NY 14613

Altair BASIC Patch Needed

I wonder if any BYTE readers couldassist me in locating the patch to Altair8 K 4.0 Version and Altair Extended 4.0Version BASICs which will allow theseBASICs to run on a Z80.

I recently purchased a TDL ZPUwhich uses the Z80. The manual notes

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this incompatibility stating that AltairBASIC "has as part of its routinesseveral occasions where the parity flag ischecked as part of the function. In theZ80 the parity flag indicatesOVERFLOW during math routines, notparity." The manual states that it con-tains a patch in Appendix C, but no Ap-pendix C is included.

If any reader of BYTE knows wherethis patch may be obtained, please letme know.

Hugh Morgan7725 Berkshire BlvdPowell TN 37849

Pascal Examples Needed

Just a short note to tell you how verymuch I appreciated Carl Helmers'"Pascal Checkbook Balancing Program"which appeared in the January 1980BYTE.

As a beginner, I don't think he"profaned Pascal by writing a simplelittle ..." etc. The program was most in-formative, and I studied it in detail. Ihave adapted it to the formulation of ametrics conversion program. It was cer-tainly clearer than most of the programexamples in the few, but confusing, textson Pascal.

I realize that in general BYTEmagazine caters to the experienced pro-grammer, but what we need are moreexamples like yours—the we being thoseof us relatively new to the art.

So thank you once again—and pleasesome more tutorials and programs!

Max Nareff

5235 Diamond Heights Blvd

San Francisco CA 94131

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10 May 1980 © BYTE Publications Inc

A Satisfied Reader Comments

I couldn't believe itl Ted Carter'sarticle "Implementing Dynamic DataStructures with BASIC Files" (February1980 BYTE, page 92) was exactly what Ineeded for a program I am writing tocomputerize billing on a newspaperroute.

I had tentatively planned my fileroutines, but I scrapped my ideas afterreading the article.

James E Nichol1416 Oak Knoll DrCincinnati OH 45224 ■

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VB3 is memory mappedfor rapid screen updating. But itoccupies memory only whenactivated. So one or more VB3scan be located at the sameaddress with a full 65K of mem-ory still available to the user.

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The Cassette Lives On

An Alternative to Floppy-Disk Mass Storage

Emory Cook

Cook Laboratories Inc

375 Ely Ave

Norwalk CT 06854

In a world where floppy and harddisks are becoming more affordablefor the average small-business userand hobbyist, sequential mass storagein the form of cassette tape is gainingdisfavor. Still, many disk users get in-to trouble when something happensto a floppy disk and they have notmade backup copies. Although anybackup system requires the time andinconvenience of regularly carryingout the file-copying procedure, oneproblem with using floppy disks forfile backup is the cumulative cost ofthe number of disks needed to main-tain backup copies of all records.

The Cassette Solution

What is needed is a low-cost filingmedium. Cassette storage is theanswer, provided we take thenecessary precautions to make itreliable. Old files, such as files ofrecords for last quarter, last year, andthe years before, belong on cassette.The disk-to-cassette transfer for back-up purposes becomes sensible interms of both expense and security.With adequate tape recorders andhigh-quality cassette tapes (which useboth quality tape material and quali-ty mechanical housings) cassettestorage can and does become highlydependable.

Let's go a step further. Anyonewho is using a microcomputer andneeds its daily functioning will beacquiring a spare microprocessor.With a three-head, audio-cassette

machine,which has a separateplayback head following the recordhead (a common piece of high-fidelity equipment), the spare micro-processor can readily be set up with amachine-language program. Thisprogram verifies a backup tape byreading the information immediatelyas the tape is written. [The sameresult can be accomplished (a bitslower, however) for those of us whocannot afford a spare microprocessorboard or an expensive cassette re-corder. This can be attained by usinga verification program running on thesame microprocessor to reread thenewly created tape and compare itsinformation with the contents ofcomputer memory... ,GW]

Floppy disks may be aglamorous way to storeprograms and data, butthe cassette is far fromdead.

When records are backed up at theend of some reasonable period (ie:day, week, month, etc), the extratime needed to dump the records tocassette at a low transfer rate is not anoverwhelming disadvantage. A se-cond backup tape simultaneouslymade with a second recorder isalways a good idea. In other cases,one cassette copy can simply serve as

a backup for printed records, thussaving time, printer wear, ribbons,and paper.

For even the most inexpensivecassette deck, a small amount ofmoney and attention can result in thefollowing:

• excellent performance and relia-bility (no more trial-and-erroradjustment of the volume control)

• a very low error rate (statisticallyas good as that of a 5-inch floppydisk)

• the lowest possible cost per bitstored

Problems with Cassette Storage

The main problems with currentlyused cassette-storage methods aredirt, variation in tape speed, prob-lems with azimuth alignment, andinferior tape quality.

Dirt collects on the tape recorderhead from several sources, from theroom, from dust left on poorlymanufactured tapes, and sometimesfrom sweaty fingers attempting towipe the head clean. The tape headand the pressure roller can be cleanedusing pure alcohol and a cotton-tipped swab.

Periodic cleaning is imperativewhen using poorly manufacturedtapes. Cassette tapes are manufac-tured by slitting a 30.5 cm(12-inch)wide sheet of magnetic material calleda web. Slitting is accomplished withknives, which often get dull from cut-

12 May 1980 © BYTE Publications Inc

Circle 4 on inquiry card.

^*od

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ting the inherently abrasive magneticcoating. If the knives are notperiodically sharpened (which is thecase in making some inexpensivecassettes), the dull knives cause a finepowder of magnetic coating to collecton the edges of the tape. As a result,abrasive magnetic powders come incontact with the tape head when thecassette is later played. The poorerthe quality of the tape, the greater thechance that this is occurring.

Variation in tape speed can becaused by belts slipping within thecassette recorder, but it is more oftencaused by flaws in the pressure roller,which with the capstan is meant topush the tape through the machine ata constant speed. Leaving the taperecorder set in play mode with themotor disengaged (as is done inseveral current personal computersystems that let the computer controlthe tape motor) may eventually causeindentations on the pressure roller,with some inevitable variation in tapespeed. This variation impairs thereliability and the data-transfer rateof the cassette interface, so it is im-portant to keep the pressure rollerclean at all times and disengagedwhen not in use.

Azimuth of the tape head refers tothe angle between an imaginary linedrawn in the direction of tape move-ment and the vertical, magnetic gapon the record/playback head of thecassette recorder. This angle shouldbe 90°-that is, the tape should run

straight across the tape head, per-pendicular to the magnetic gap. If thetape head is somehow knocked out ofalignment (which happens frequent-ly, although nobody knows how), itmust be restored if the tape recorderis to faithfully play back a recordedtape.

There is an adjustment mechanism,usually a small Phillips screw, on theleft-hand side of most tape heads.However, some tape recorders do notallow you to reach the mechanismwhen the recorder is in the playmode. Because of this, it is importantto do one of two things: either buy acassette recorder that has an azimuthaccess hole, or have a good craftsmancarefully drill a hole over the screw sothat it can be reached with a tinyscrewdriver when the recorder is inthe play mode.

Recording with a Peak-Signal-Strength Meter

It is the peak output, not theaverage or the root-mean-square val-ue of the cassette signal, that mosttape interfaces are sensitive to. In or-der to repeatedly load cassette tapeson the first try, you must be able tosend a signal of known strength to thecassette interface. However, mostcomputer systems give us no feed-back on cassette signal strength—inother words, we are operating "blind-ly." Let us use the TRS-80 Level IItape format as an example. Thecassette input port terminates within

the TRS-80 with a resistance of 100ohms. A signal from the cassette witha peak level of about 2 V is needed toinsure a correct load. If the cassetterecord/playback head is correctlyaligned with the tape, and the signalis adjusted (via the volume controland our peak-signal-strength meter)to a peak level of 2 V, then theTRS-80 (or whatever computer youhave) should load correctly everytime.

Figure 1 presents the circuit for apeak-signal-strength meter. Thesignal from the cassette recordercomes in jack 1 and goes out jack 2 tothe computer. Two halves of anLM358N dual operational-amplifierdevice are used to create a circuit thatis highly sensitive to voltage changesin the 2 V region.

Although component layout is notcritical, a full-size, printed-circuit-board pattern for this circuit is givenin figure 2. A 9 V transistor radio bat-tery will have a life of around 2000hours of continuous use. The unit canbe calibrated by marking the milli-ammeter dial while applying a knownvoltage from a DC 1.5 V flashlightbattery cell; the reading should notchange significantly when the polari-ty of the input voltage is reversed.The circuit is reasonably accurate inmeasuring peak voltages of signalswith a frequency of up to 20 kHz, andit will then give good accuratereadings as long as the 9 V batterysupplies 5 V or greater.

Number Type +9V GNDIC1 LM358N 8 4

POWER

Figure 1: Schematic diagram of peak-signal-strength meter. This meter enables the user to present the cassette interface with a signalof known peak intensity—usually, about 2 V. The circuit is designed to be sensitive to voltage changes around the 2 V area.

14 May 1980 © BYTE Publications Inc

Circle 5 on inquiry card.

From Percom

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• Compatible with EXORciser* and other6800/6809 computers based on EXORciser* busconcept.

• 40- or 77-track drives in one-, two- and three-drive configurations add 102K bytes to 591Kbytes of random access data on-line.

• 40-track LFD-400BC drives store data on bothsurfaces of mini-diskettes — almost 205K bytesper disk.

• EXORciser* bus compatible controller includes1K of RAM, provision for 3K of PROM. Maturedesign features explicit clock-data separator,drive motor inactivity time-out function, andmore.

• Support software includes disk operating sys-tems, a file manager, text editor, assembly lan-guage program development/debugging aids,an extended BASIC interpreter, an SPL/M com-piler and business programs. Numerous pro-grams available from other suppliers may beused with LFD-400/800EX mini-disk systems withlittle or no modification. Watch for FORTRAN & Pascal !announcements.

Low cost Percom LFD-400/800EX mini-disk data storage systems are a fast,dependable alternative to tape storage for 6800/6809 EXORciser* bus compu-ters. A single 40-track LFD-400EX'" drive adds 102K bytes of formatted on-linestorage; a single 77-track LFD-800EX"* drive adds almost 200K bytes. And datamay be stored and read from either surface of LFD-400EX1" minidiskettes.

Fast mini-disk data storage makes your Motorola EXORciser* or otherEXORciser* bus computer more than just a development system or limitedevaluation system.

For example, at the low LFD-400/800 EX prices it becomes economical touse your development system as the final working system.

Data capture/retrieval in research, test and production environments isanother application where versatile, random-access LFD-400/800EX storage canprovide efficient operation.

Equipment control is yet another area where the speed and facility ofmini-disk storage greatly expands application possibilities. Even if you use amini-disk only to load and control programs you'll save simply by taking a lotless time than with slow, inconvenient tape storage. Moreover, by storingprograms on fast-loading, low cost minidiskettes you eliminate the overhead ofburning PROMs — an expense that quickly adds up to far more than the price of

sn inexpensive Percom mini-disk system.

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Includes driver utility listings, controller schematic $15.00The system prices are single-quantity prices. A system in-cludes (1) the drives, power supplies and enclosure, (2) theEXORciser* bus compatible controller PC card with 1K RAMand provision for three 2708 EPROMs, (3) an interconnectingcable, (4) an 80-page users instruction manual, and (5) asystem minidiskette. The Percom Software Services Groupwill customize the MPX DOS for a nominal charge if one of thestandard versions is not suitable for your monitor. LFD-400EX*" systems use 40-track drives; store 102K bytes offormatted data per minidiskette side. LFD-800EX"8 systemsuse 77-track drives; store almost 200K bytes on one side ofminidiskette.

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Checking the Recorder Azimuth

If your tape recorder has anazimuth-adjust screw, adjusting theazimuth angle is a simple procedure.You must first place in the cassetterecorder an azimuth-calibration tape(see text box) or a similar cassettetape recorded on a machine known tobe properly aligned. Then, playingthe cassette and monitoring therecorder output with the peak-signal-strength meter, turn the azimuth-adjust screw until the meter reachesits maximum reading. The readingdrops off on both sides of the optimalposition.

The meter can also be used to getthe best reading from a tape that wasproduced on a tape recorder withfaulty head alignment. Simplymonitor that tape with the peak-signal-strength meter, adjusting theazimuth-adjust screw until therecorder gives the strongest reading,and use the recorder to load andverify the tape. Once this has beendone, the recorder can be realignedand a new tape can be made that youcan later load without the same kindsof adjustment.

One method of improvingthe reliability of cassettetapes is to modify thesignal coming from thecassette recorder.

Problems with Reading Tapes

With most computers, you willneed to load a tape using an inputpeak-signal level of about 2 V (whichwill appear as about half-scale on themilliammeter of the peak-signal-strength meter). With only slight var-iations due to a particular comput-er/recorder combination, the samereading from the peak-signal-strengthmeter will result in effective loads. Acassette tape coming from a recorderwith a misaligned head will give alower reading than a correctly record-ed tape for the same volumesetting.First try to load the tape afterincreasing the recorder volume untilthe peak-signal-strength meter givesthe customary peak reading. If thisdoes not work, you will have to loadthe tape after adjusting the azimuth in

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the manner previously described.

Whenever the tape head is mis-aligned with respect to the tape path,the peak-signal intensity will flutter,even if the tape being played wasrecorded correctly. This effect iscalled skew. If the signal variation issevere enough, you will be unable toload the tape properly due to datadropout. Signal flutter due to skew isa subtle problem; it will not show ona meter because no meter needle canmove fast enough to follow the flut-ter.

Flutter can also be caused by tapeweave, which has a variety of causes.If the pressure pad opposite therecord/ playback head is not posi-tioned properly, it will tend to pushthe tape away from the center of thehead. This is aggravated by the factthat most cassette recorders do notmaintain tension on the supply reel,allowing the pressure pad to pull outtape freely and push the tape awayfrom the center line of the head. Also,a tape with a thin backing is moresusceptible to tape weave.

Altering Tape Waveforms

Another method of improving thereliability of cassette tapes is tomodify (and sometimes rerecord) thesignal coming from the cassetterecorder. For example, severalwaveform-changing interfaces thatimprove the loading reliability of thecassette are available for the Radio

Figure 2: Full-sized, printed-circuit-boardpattern for the peak-signal-strength metercircuit of figure 1.

16 May 1980 © BYTE Publications Inc

Circle 6 on inquiry card.

There is only onehigh performance

VLSI computer

solution.

Intel delivers it.

Tools to solve the

How Inteldelivers the keyto productivityin the '80s.

As we move into the '80s, theincreasing demand for complex com-puter programs, the critical shortageof programmers, and the seeminglyunstoppable rise in software develop-ment costs will reach crisis proportions.To understand how to bring thissituation under control, we have tounderstand its cause.

In the 1970s, the microcomputerwas used successfully to lower the costof hardware engineering. Each newmicrocomputer generation integratedmore and more of the system, loweringthe cost of design and making it easierto put electronic intelligence anywhereand everywhere. As hardware costdropped, rising software costs becameincreasingly visible.

So, today, as costs climb, manage-ment puts everyone under increasingpressure to deliver projects on time andon budget. Yet, the cost of programmingis still outpacing productivity. Softwaredevelopment and integration stilllag the system hardware. The softwarecrisis of the '80s rages on.

Tools for structured solutions

Once a problem grows beyond acertain point, the most efficient way tosolve it is with a top down approach.You break the problem into units,program and debug each one, and com-bine the units into a unified solution.

That's the concept. But you can'tstop there. In the '80s, bridging the gapbetween a conceptual solution and aworking one will require tools asefficient as the top down method. Newtools, like a CPU with a dramaticallydifferent architecture. An architectureuniquely suited to a world of higher levellanguages and structured programming.Tools like a modular operating system,of a kind never before available on a16-bit microprocessor. Tools like the

software crisis.

Co-processors

PeripheralControllers

Microprocessors

Software

^^SL

only complete family of programminglanguages, because no one languageis right all the time.

Different languages have differentstrengths and weaknesses, and using therigh r language for the right job canmake your programmingeasier. So, Intel deliversASM86 Macro As-sembly Languagefor space andspeed sensitivemodules. OurPL-M/86 sys-tems program-ming languageand PASCALsupport structuredprogramming atthe systems and ap-plications levels. FORIRAN and COBOLwill also be available.

With Intel's re-location and link-age tools, moduleswtitten in the

different languages are combined, withlibrary utilities and operating systemroutines, into one, complete solution,automatically. Using this modularapproach, and the right language forthe right job, your finished product isclean, reliable, maintainable, andunderstandable.

The critical module

Since complex softwate requiressophisticated operating systems support,the operating system is the most criticalmodule in your solution. It is the foun-dation upon which your application isbuilt. It is also available, off the shelf,from Intel.

Today, Intel delivers the RMX/86™operating system. RMX/86 is new, and it'sthe first modular, real-time, multitaskingoperating system for 16-bit microcom-

Memories

Software

Development

Systems

Intel Structured System

upon the features you select, you savefrom two to forty man years of program-ming effort. That's an additionaltwo to forty man years you can devoteto your application.

Tools for realizing yoursolution

Of course, havingthe foundation andthe concept of yoursolution doesn'thelp if you can'twrite the pro-grams to imple-ment it. So, Inteldelivers develop-ment tools to sup-port you throughthe entire develop-ment cycle. Supportfrom source entry, withCREDIT, a CRT based texteditor, through com-piling and debugging,with an Intellec®development systemand ICE™ hardware/software debuggingsystem. Intel's tools work with you. Theyshorten development time and supportthe structuted approach you've taken.

But debugging softwate on adevelopment system is not the same astesting it on the actual hardware.The ICE modules help here, too.During development, these tools letyou trace through your software anddebug it, symbolically, at the sourcelanguage level. Now, these In-CircuitEmulators replace your prototypehardware's CPU to speed hardware/software integration.

If your hardware is built fromcomponents, ICE Modules will help youseparate the hardware and softwarebugs, so you don't spend your time fixingengineering problems. If your hardwareis built around an Intel iSBC 86/12A™Single Board Computer, you'll already

puters. File manipulation, task schedul

ing, and interrupt control are configured by have a known, working hardware

you, according to the needs of your appli- environment for program testing,

cation. There's no unnecessary burden. You can use ICE Modules to concen-

Intel's investment in the development trate your efforts on debugging your

of RMX/86 is substantial. Depending software.

Either way, the same software,opetating system support and debuggingtools are available to help you bringyour application to life.

Synergy for high performance

In the '60s and '70s, programs wereused to instruct computers. Applicationsof the '80s require programs to be thesolutions to problems. High perfor-mance solutions will be the result ofsynergy between the hardware andthe softwate.

To create this synergy today, Inteldelivers the 8086 processor. The 8086processor is unique. Instead of a linear,or flat architecture, the 8086 is theonly microprocessor optimized to workwith high level languages and thestructured solutions they implement.

For the specialized needs of the '80s,the 8086/87 and 8086/89 co-processingsystems will set the standatd of per-formance for mathematical processingand I/O bound applications.

And Intel peripheral controllerscontribute to your system throughputby freeing processors for morecomputation.

Your software design may berevolutionary. And with help from anarchitecture designed to support yourstructured solution, its performancecan be revolutionary, too.

Intel's software tools let you con-centrate your planning on the payoff—getting to market today with a superiorproduct. To take your first step tohigher productivity, fill out and mailthe coupon on the other side of this page.It's a productive use of your time.

Europe: Intel International, Brussels, Belgium.Japan: Intel Japan, Tokyo. United States and Canadiandistributors: Alliance, Almac/Stroum, Arrow Electronics,Avnet Electronics, Component Specialties. Hamilton/Avnet.Hamilton/Electro Sales, Harvey, Industrial Components,Pioneer, L.A. Varan, Wyle Distribution Group, Zentronics.

\bur first step toward productivity

How to get moreinformation onsolving the softwarecrisis of the '80s.

To find out more about oursolutions, fill out the informa-

tion requested below and sendit to Intel Corporation, LiteratureDepartment, 3065 Bowers Avenue,Santa Clara, CA 95051. Indicatewhat your particular interests are,including workshops, and we'llmake sure you get the appropriatematerial. If you don't have a pair of

scissors handy, give us a callat 408/734-8102 (LiteratureDepartment) and we'll rush thematerial out to you. Or callyour local Intel distributor.

Intel wants to help you solvethe software crisis of the '80s.It all starts right here.

Name_Title _

Company.Division

Address

City, State, ZIP.

I have an immediate requirement, please telephone me at ( )

I need additional information.

Please put the letter corresponding to your yearly requirements in the line to the left of thoseproducts of interest.

W for 1-10 per yearX for 11-99 per yearY for 99-999 per yearZ for over 1,000 per year

A 16-bit Microprocessors

B 8-bit Microprocessors

C Single-ChipMicrocontrollers

D Peripheral Controllers

E RAMS

F EPROMS

G Bubbles

H Single Board Computers

I Development Systems

J Debug Tools

K High-Level Languages

Indicate languages

L Macroassembler

M Operating Systems(RMX/86™)

N Telecom Products

O Military Products

P Workshops

012345

Circle No. 426 for information.

Copyright c Robert Tfnn«y 1978

Beautiful "Computer Chess" Reproduction—only $4.95!

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The price of this quality reproduction is $4.95,plus $1.00 for mailing tube,handling, and postage. In addition, the artist, Robert Tinney, will select the y100 finest prints from this first edition for his personal signatinumber. These 100 signed and numbered printson a strictly first-come basis for $24.00 plus $1.Cpostage and handling.

See coupon below for ordering.

Shack TRS-80. About two wintersago here at Cook Laboratories, wedeveloped a modified tape formatthat records more reliably on theTRS-80. Without going into thedetails of the TRS-80 tape format, Ican say that the unaltered tape signalcrowds too much information into agiven space and thus opens itself toreliability as well as saturation prob-lems. The latter problem is whatmakes the TRS-80 normally so vol-ume sensitive. The waveform we useat Cook Laboratories, when record-ing tapes for the TRS-80, reorders thewaveform shape and narrows thepulse width so that the cassette inter-face does not get confused.

The various waveform modifica-tions could certainly be used to im-prove the reliability of the cassettestorage on other microcomputers. Forexample, on the old-model PETs,there is no way to alter the volumelevel of the built-in cassette recorder.However, Commodore can provide adocumented program called S-21.This program, when running,monitors tape being played in thePET cassette deck and displays cer-tain information about the quality ofthe tape signal on the PET screen.This is a very effective program tohave if you know how to use it; Com-modore is the only manufacturer Iknow that supplies a program like it.

Tape Is Also a Factor

Several factors having to do with

the cassette tape itself can also affectthe reliability of tape loading. As Imentioned before, a tape that is toothin will likely give in to tape weave.Tape stiffness is a property of thethickness of the backing and is pro-portional to the third power of thegauge thickness of the backing. Thisindicates that you should not uselong-playing cassettes for programand data storage.

The thickness of the magneticcoating affects the reliability ofcassette storage, but in a differentway. Standard audio tapes, chrom-ium dioxide or otherwise, are not op-timal for digital recording becausethey are designed to give good fre-quency response in the low frequen-cies. But low frequencies are notneeded here; rather, well-defined andsharp waveform transitions are whatcount. A thinner magnetic coatingthan what is used in standard audiocassettes results in nice improvementsboth in waveform resolution andsharpness of transition. Not inciden-tally, Cook Laboratories markets acustom line of digital cassettes underthe trademark MICROFUSION. Thistape has a thinner chromium dioxidecoating and a heavier and, therefore,stiffer backing, both of which make itwell suited for digital storage.

Cassette tapes can be used forreliable mass storage if the taperecorder is kept clean and properlyaligned, if quality tape (especiallytape made for digital storage) is used,

and if the signal going from thecassette to the computer is monitoredand kept constant (from tape to tape)with a peak-signal-strength meter.Although disks are readily availableand bubble memories are not faraway, no medium will ever becomeobsolete as long as it provides a need-ed function. Cassettes, too, are hereto stay.H

The following items are availablefrom Cook Laboratories, 375 ElyAve, Norwalk CT 06854:

AZ-80 Precision azimuth cas-sette, chromium dioxide.$14.95PK-80 Kit for peak-signal-strength meter, includingboard, litho panel, screw-driver, meter, case, andinstructions, less battery$25.90AZ-B1 Printed-circuit board forpeak-signal-strengthmeter, etched and drilled$2 50MICROFUSION digitalcassette, C-10 $3.26

C-20 $3.68

C-30 $4.09

Add $2.00 for each order forhandling and shipping within thecontinental United States. Connec-ticut residents add 7% tax.

I The!

DO YOU SEE EYE TO EYE WITH YOUR APPLE?

DS-65 Digisector* opens up a whole new world for your Apple II. Your computer can now be a part of the action, taking pictures to amuse youfriends, watching your house while you're away, taking computer portraits... the applications abound! The DS-65 is a random access video digitizerIt converts a TV camera's output into digital information that your computer can process. The DS-65 features:

• High resolution: 256 X 256 picture element scan• Precision: 64 levels of grey scale

• Versatility: Accepts either interlaced (NTSC) or industrial video input• Economy: A professional tool priced for the hobbyist

The DS-65 is an intelligent peripheral card with on-board software in 2708 EPROM.Check these software features:

• Full screen scans directly to Apple Hi-Res screen

• Easy random access digitizing by Basic programs

• Line-scan digitizing for reading charts or tracking objects

• Utility functions for clearing and copying the Hi-Res screen

Let your Apple see the world!

DS-65 Price: $349.95

Advanced Video FSII Camera Price $299.00

SPECIAL COMBINATION PRICE: $599.00

/our ■

THE,

1 W@C^£g

APPLE SELF-PORTRAIT

P.O. BOX 1110 DEL MAR, CA 92014 714-942-2400

J

18 May 1980 © BYTE Publications Inc

Circle 7 on inquiry card.

Circle 8 on inquiry card.

PROGRAM EPROMS

WITH YOUR APPLE

NEW FROMMOUNTAIN HARDWARE

ROMWRITER™

FASTER THAN A SPEEDING DISK!

Firmware in ROM is as fast as your software in RAM, but inROM it frees up RAM memory space for companion pro-grams. And, there never needs to be a LOAD from disk!Create firmware for your Apple* by programmingEPROMs with RomWriter.

FIRMWARE NOT SOFTWARE.

Many frequently used programs really oughtto be installed as firmware. ROM-basedfirmware permits a "power up and go"configuration. Use RomWriter to createfirmware for peripherals such asprinters or create program cards.By installing EPROMs that youhave programmed on Mount-ain Hardware's ROM-PLUS+'" board, programcards of up to 12K inlength may be cre-ated.

FEATURES.

Programs 2716 EPROMs (5V). All 2Kor part of the EPROM can be pro-grammed. Installs in a peripheral slot.EPROMs mount in a zero insertion forcesocket. A switch turns power off to the socketGPROMs can be inserted or removed with-out powering-down your computer. A WriteProtect switch is provided for programmedEPROMs while running. A $CFFF OFF switch tosuppress this command during programming or RUNning.EPROMs can be RUN on RomWriter, or ROMPLUS+'" whencreating firmware systems.SOFTWAREVirtually foolproof programming. Specify a Start and End addressin the EPROM and either a Disk File name or a starting address inmemory. Desired code will be BURNed followed by a VERIFY. Addi-tionally, existing EPROM code can be merged with desired changesto facilitate EPROM debugging. Easy data entry and high reliabilityare designed Into RomWriter. Programmed EPROMs can be RUNwhile residing on RomWriter or can be transferred to MountainHardware's ROMPLUS+ board,requires Applesoft firmware.THE RIGHT PRICE.

See for yourself how firmware can enhance the power of your Applesystem. Drop by your local computer store for a demonstration.RomWriter and Mountain Hardware's full line of computer productsare available at dealers worldwide.

"Apple is a trademark of Apple Computer, Inc.

Available through dealers worldwide

Mountain Hardware, Inc.

JILWUJi!

LEADERSHIP IN COMPUTER PERIPHERALS

300 Harvey West Blvd.. Santa Cruz, CA 95060(408) 429-8600

• Fast Firmware? Send me all the details on RomWriter.

Name.

Address .City

. Stale.

.Zip.

Phone_

A growingline of tools toexpand the Apple.

A DC-to-DCConverter

Michael Picco

POB 516

Corte Madera CA 94925

Have you ever had the need for abipolar power source, but had only apositive voltage available? With thehelp of a timer and a few externalcomponents, this problem can beovercome. The circuit in figure 1 issufficient for powering op amps orsimilar devices requiring a supplycurrent of 25 mA or less at —12 V.

The heart of this circuit is a 555timer that provides a drive signal ofapproximately 20 kHz to a voltagedoubler. This signal is removed if the

+ 12VA

R210K

Rl2.2K

R3

56K

-VW-

DISCHARGETHRESHOLD

TRIGGER

OUTPUT

IC1LM555

CI0.001^.F

/77

Number Type GND +12 VIC1 555 1 8

magnitude of the output voltage ex-ceeds that of the supply voltage. Inthis sense, the converter operates as aswitching-mode regulator.

The output voltage is set by con-trolling the timer via the reset input(ie: pin 4). When the output voltagereaches a negative potential with thesame magnitude as the supply volt-age, a low logic state is placed on thereset input, causing the timer outputto go low and the increase in voltagemagnitude to cease. ■

R456K

■JWV-

D31N4148

C3

20/iF

15V

C2. 20/iF' 15V

D2

1N918

-H«-

. Dl-*- 1N918

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D51NS1?

H4-

j—-> OUTPUT~1 (-12V)

C5

150MF

15V

m

C4

20/iF

15V

Figure 1: Schematic for the DC-to-DC converter. The 555 timer produces a rectangularwave at about 20 kHz, which is inverted by the diode-capacitor voltage-doublerarrangement. A feedback signal reaching the reset pin of the 555 regulates themagnitude of the output, which is —12 V at 25 mA.

744! ■ iiible Interrupt Timer Module.

Time events in four operating modes—continu-ous, single shot, frequency comparison, andpulse width comparison. Includes three 16-bitinterval timers, plus flexible patch area forexternal interface. Programmable interrupts,on-board ROM, and much more.

7720A Parallel Interface. Two bi-directional 8-bitI/O ports will connect your Apple to a variety ofparallel devices, including printers, paper tapeequipment, current relays, external on/offdevices. Full featured, programmable inter-rupts, supports DMA daisy chaining.

7811B Arithmetic Processor. Interfaces withApplesoft, so you just plug in and run. Basedon the AM 9511 device, provides full 16/32-bitarithmetic, floating point, trigonometric, loga-rithmic, exponential functions. Programmed I/Odata transfer, much, much more.

7710A Asynchronous Serial Interface, Conform-ing to RS-232-C A thru E1978 standard, thiscard will drive a variety of serial devices such asCRT terminals, printers, paper tape devices, orcommunicate with any standard RS-232 device,including other computers. Full hand-shaking,and fully compatible with Apple PASCAL!

7470A 3% BCD A/D Converter. Converts a DCvoltage to a BCD number for computerizedmonitoring and analysis. Typical inputs includeDC inputs from temperature or pressuretransducers. Single channel A/D, 400 msper conversion.

7490A GPIB IEEE 488 Interface. A true imple-mentation of the IEEE 488 standard—thestandard protocol for instrumentation and testdevices. Control and monitor test instrumentssuch as digital voltmeters, plotters, functiongenerators, or any other device using theIEEE 488.

7114A PROM Module. Permits the addition to orreplacement of Apple II firmware withoutremoving the Apple II ROMs. Available withori-board enable/disable toggle switch.

7500 A Wire Wrap Board. For prototyping yourown designs.

7510A Solder Board.

7590A Extender Board.

7016A16K Dynamic Memory Add-On.

Watch this space for new CCS products forthe Apple. We've got some real surprises in theworks. To find out more about the CCS productline, visit your local computer retailer. The CCSproduct line is available at over 250 locationsnationally, including most that carry the Apple.Or circle the reader service number on this ad.

Apple II, Apple II Plus, and Applesoft are trademarksof the Apple Corporation.

CCS makes the difference.

20 May 1980 © BYTE Publications Inc

Circle 9 on inquiry card.

We see the Applea little differently.

Oat'

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We see it as a goodway to get things done.

Apple has built a great computer. We at CCS havebuilt a great line of peripherals and components to expandthe Apple. To do almost anything you want to get donewith a computer.

If you want to do business with an Apple, we've gottools to connect the Apple to standard business printers andterminals. Or to modems, for communications over tele-phone lines, with other computers, even with other Apples.

If you want to apply your Apple to engineering, scien-tific, or graphic projects, we've got tools for high-powered,

high-speed math functions, and fast, high resolution graph-ics. And tools to connect the Apple to lab test equipmentlike function generators or plotters.

And we have tools to connect the Apple to the outsideworld, including A/D converters and interval timers withexternal interface.

We make components for the S-100 bus, the PET, andthe TRS-80, too. We built our products to deliver hard-nosed value to the OEM, and to the inventor who knows thebest, at prices that are unbeaten.

To find out how much computer your Apple II can be,see things our way. Because for serious users with serioususes for the Apple, we've got the tools.

California Computer Systems

250 Caribbean Sunnyvale, CA 94086 [408)734-5811

Gisrcis's Circuit Gellap

> Copyright © 1980 by Steven A Ciarcla. All rights reserved.

I/O Expansion for the Radio

Shack TRS-80

Part 1: Principles of Parallel Ports

Steve Ciarcia

POB 582

Glastonbury CT 06033

I receive a lot of mail: enough thatI'm beginning to feel like the "DearAbby" of the personal computerranks. The sources of the letters rangefrom high school students asking foradvice on science fair projects to ma-jor corporations seeking consultantservices. Even though it takes con-siderable time to answer this mail, Iregard it as a significant opportunityto gauge reader interest. Every letterin some way contributes to my choiceof article topics, either through sug-gestions or by continued occurrenceof similar questions.

Recently, my mail has beendominated by owners of the RadioShack TRS-80 Model I thirsting forhardware expansion by means otherthan Tandy Corporation equipment.The majority of questions concernconnection of my interfaces to theTRS-80 expansion connector.

In general, I have tried to presentprojects that are computer indepen-dent. That is, the interfaces describedare driven through parallel input/output (I/O) ports rather than direct-ly from a computer bus. This had notbeen a problem in the past, becausevirtually all of the early personalcomputers incorporated some parallelI/O capability. For those exper-imenters interested in enhanced I/Ocapabilities, I presented the article

"Memory-Mapped I/O" in theNovember 1977 BYTE on page 10 (re-printed in Ciarcia's Circuit CellarVolume I, BYTE Books), whichdetailed parallel-port construction.

In the 2Vi years since that articlewas first published, a number of

A port is a hardwarechannel for the computerto transmit and to receivedata via an externalperipheral device.

significant changes have occurred inpersonal computing. Most important-ly, the Radio Shack TRS-80, the Ap-ple II and the Commodore PET wereintroduced. The difficulty in main-taining and operating a computer isno longer a serious consideration formost computer enthusiasts. Much ofmy mail indicates that a new explana-tion of parallel and serial I/O is inorder, and that it is time forhardware-expansion circuits to bedetailed.

This month's Ciarcia's CircuitCellar is the first of a two-part articleon serial and parallel I/O port expan-sion of the TRS-80. The first part em-

phasizes parallel I/O, and the secondpart is concerned with serial interfac-ing. The result will be a completeRadio Shack software-compatiblecommunications interface capable ofsupporting a variety of serial- andparallel-interfaced peripheral devices.The hardware was designed and thecomponents were selected to beeconomical to build and easy to checkout. First, here is a brief review of thebasics.

What Is an I/O Port?

Just as some people are initiallyconfused with the terms hardwareand software, some find the conceptof input and output ports difficult tounderstand without substantial ex-planation. The classical definition: aport is a hardware channel for thecomputer to transmit and receivedata via an external peripheraldevice. The key words in this defini-tion are external and data which imp-ly externally collected information;the channel through which this data isobtained is called a port. A printer isa typical external peripheral device.The characters to be printed are sentfrom the computer to the printer. Insome of the more sophisticated units,status signals such as busy and out ofpaper are returned to the computerfrom the printer.

22 May 1980 © BYTE Publications Inc

Ports can be either parallel orserial. In parallel mode, data istransferred in increments equivalentto the word size of the computer. Onthe Z80, for instance, an 8-bitmicroprocessor, an output instruc-tion through a parallel port transfers8 bits at a time. A 16-bit processorsuch as the Intel 8086 transfers data in16-bit increments. The number of bitstransmitted simultaneously by aparallel port is dependent upon thesize of the microprocessor data busand how many bits the processor cantransfer simultaneously.

However, serial data is alwaystransmitted a single bit at a time, ac-cording to a fixed schedule defined bythe data rate (usually expressed in bitsper second, or bps) and a few specificoptions. The microprocessor has nosingle instruction that transmits serialdata. It must rely on another devicecalled a universal asynchronousreceiver/transmitter (UART) to putthe data word into serial form andtransmit it. Any communication be-tween the processor and the UART isin parallel form and is done throughthe processor's memory reference orI/O data-transfer instructions. Amore in-depth discussion of serialports will be presented next month inPart 2.

Address, Data, and Control Buses

Consider a computer system thatincludes a printer, video terminalwith keyboard, and an audio cassetterecorder as peripherals. Data wouldhave to be relayed to the printer, toand from the video terminal, and toand from the cassette recorder. Howcan the computer tell the differencebetween data destined for the ter-minal and the data destined for theprinter?

Most microprocessors incorporatea bidirectional data bus and an ad-dress bus: this is shown in figure 1.To keep track of the data transfer be-tween the processor and its peripher-als, the system uses a quantity of con-trol signals which together can becalled the control bus. The usual 8-bitprocessor has an 8-bit data bus, a16-bit address bus, and a dozen or socontrol signals.

When the microprocessor is read-ing a data byte from memory, the ad-dress of the memory location beingreferenced is placed on the addressbus. Memory information stored at

that location goes on the data bus andflows from memory to the processor.When data is being written intomemory, the operation is reversed. A16-bit address bus allows the pro-cessor to directly address 65,532 (ie:64 K) memory locations.

In an 8080 or Z80 processor there isa specific set of instructions that per-form input/output functions. Theoperation of these I/O instructions issimilar to that of memory-referenceinstructions, except that only 8 bits ofthe address bus are used. These 8 bits

Photo 1: There are a variety of ways to decode the address for a particular input/output(I/O) port from the signals present on the address bus. The least expensive method usesinverters and printed-circuit-board jumpers to select the correct logic polarities. Threeaddress lines are connected through each 7404 hex inverter with two possible connec-tions for each address line. A connection to the upper trace on the circuit board decodesa logic I; a connection to the lower trace decodes a logic 0.

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Photo 2: A more expensive and more easily changed addressing scheme employs dual-in-line-pin (DIP) switches and exclusive-NOR gates. The schematic diagram for this isshown in figure 3b.

May 1980 © BYTE Publications Inc 23

Circle 10 on inquiry card.

Have some

greatmemories.

16K PROM boards.

■ PROM card has 2708-type memory

■ Quality board construction ■ 0-4 wait states

■ Address any 4K group to any 4K boundary

■ Control up to 8 banks of memory ■ Fullyassembled and tested ■ PRICE—$300

{California residents add 6% sales tax)

Expandable 5 MHz RAM boards.

8—32K expandable RAM board uses TI 4044memory ■ Runs at 5MHz ■ Fast 250ns accesstime ■ Bank select ■ Address any 4K block toany 4K boundary ■ Quality board construction

PRICE—8K—$210; 16K—$378; 24K—$570;32K—$744; 8K add-on kits—$162

(California residents add 696 sales tax)

Call or write Artec for details

^RTeCGLGCTROMiajhC

605 Old County Rd., San Carlos, CA 94070Telephone (415) 592-2740

Photo 3: Prototype of an 8-bit I/O port for the Radio Shack TRS-80. The ribbon cableat left connects to the expansion port on the keyboard/processor unit. The two I/Oports are brought out to the ribbon-cable connector on the right edge of the board.

designate one of 256 possible I/Oports. In the case of the examplesystem, a separate port addresswould be used for each peripheral.

Keeping track of bus direction andinformation flow is a matter of pro-perly decoding the control signalsduring program execution. In a Z80for instance, any memory-referenceoperation is signified by the controlsignal MREQ in the processor goingto a logic 0, or low, state. An input oroutput operation is designated by the

I/OREQ control signal being atlogic 0.

The direction of the data busdepends on whether the processor istrying to read or to write data. If theprocessor is in a read mode, the RDcontrol signal becomes a logic 0; if theprocessor is writing, the WR line isin the 0 state. Monitoring these fourlines, MREQ , I/OREQ , RD , and

WR , gives us all the informationnecessary to support I/O decodingfunctions. Figure 2 demonstrates howthese control outputs are combinedfor system use.

Address Decoding

So far we have discussed how todetermine when the processor wantsto send a character to an outputdevice. In such an operation theI/OREQ and WR lines are bothlow. To tell the difference between

data for the printer and data for theterminal, we must decode the 8-bitport address.

The port address is determined bythe logic voltages present on the low-order eight lines (that is, the 8 leastsignificant bits) of the address busduring I/O operations. Varioustechniques can be employed to de-code these lines. Figure 3 outlines afew simple methods. The objective,whatever the logic employed, is toproduce a single pulse (ie: a strobe)whenever the logic states representinga particular address appear on the ad-dress bus. To eliminate false outputswhen the processor is executing in-structions not dealing with I/O, it isbest to combine control and addresssignals as demonstrated in figure 4.

If you own a 6800- or 6502-basedsystem, you have probably noticedthat the processor has no special I/Oinstructions. This does not mean thatthese processors have no externalcommunications capability, only thatthese processors communicate withperipheral devices differently. Howcan we discover this differentmethod? Let us begin by lookingclosely at the I/O functions of the8080 and Z80 that we have justdiscussed.

A close inspection of the I/O func-tions of an 8080 or Z80 should point

Text continued on page 30

24 May I960 © BYTE Publications Inc

Circle 11 on inquiry card.

A .

iHk^^^S la . .^V

HMDRRULICTUTOR

LJJ.TAN. .m«TtwrlffnViwiiMiw KBttfT&tt "

VIDEO DATA PROCESSOR

Called the VDP, comes completewith 16K memory, its own color textand graphics generator and isdesigned to superimpose itsgraphics and text over incomingvideo signals from video tape,video disk, TV camera, AppleVideo or Broadcast • Color textand graphics on an independentscreen • Video titling or videointeractive training uses. It's likeyour own TV station, works withOUR Light Pen too! Availabledirectly from Symtec at $1500.00.

SPECIAL PROBLEMS

We can help. Symtec does customengineering, fabrication, hardwareand software design formicroprocessor. Beginning at$1500, these services can solveyour custom application needs forindustrial, scientific, medical,engineering or personal uses.

SUPER SOUND GENERATOR

Apple Music Power with a plus3 voices, 6 in stereo version •Noise generator • Independentcontrol of volume, envelope andshape by channel • Full power,easy to use software to compose,edit, play in hi-res graphics, PLUS,input and output ports allow extrauses: • Printer interface • RemoteASCII or music keyboard interface• and, optional BSR X-10 Adapteris available. Suggested retail$159.95 mono, $259.95 stereo.

SYMTEC X-10 CONTROL

Now for the Apple II, a low costcontrol to link your computer to theBSR X-10 Home Control System.Control your home or office lightingand appliances • Energymanagement • Display lightingSecurity and more. Suggestedretail $49.95.

LIGHT PEN

A professional quality, full featurelight pen for the Apple II Computer

• Hi-resolution — draw on thescreen • X, Y and sensitivityadjustments — fits any standardTV • Sync adjustment for remotevideo source • Touch switch setsinterface flag • Rugged metal case

• Recommended by Apple.Complete, ready to go, the SymtecLight Pen is provided with softwareand documentation in Basic,Applesoft and machine code.Muse's Pilot II Language using theSymtec Light Pen is also available.The Light Pen is useable forgraphics, games, education,exhibits, freedom from thekeyboard. Suggested retail$249.95.

j^nkes: IITC.

i Dealei loi a demonstrationSuporsound Gsnaratoi or 8\

directly from Symtec. AppJa if a trada marh ol AppleComputet inc B8R System x 10 Is a trade mark of BSRLtd Musn is the trade mark ot Micro Users Sotit xchange, Inc

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Circle 12 on inquiry card.

WQWT

SENSATION!

You have been reading about our astoundinghigh performance microcomputer products.Our X-9000 Pascal MICROENGINE"" CPU thatexecutes Pascal 13x faster than an LSI-11and 3xfasterthanaPDP11-34.0urX-920CRT matches the features of the SOROC IQ140.Our x-8000 16-bit CPU addresses BM bytesof memory directly and is coming soon!

'Trademark Western Digital Corporation

DISPLAY/EDIT TERMINALModel X-920

$920

S820 (Without 18 function keys)

STANDARD FEATURES (partial list)

• Microprocessor controlled

• Serial RS232C and 20 ma current loop

• 10 baud rates—75 to 19,200

• 24 lines x 80 characters

• 96 ASCII displayable characters

• Upper and lowercase

• 12 x 10 character resolution

• Dual intensity display

• Clear full intensity data only

• Programmable reverse video

• Programmable underline

• 105 keys with alpha lock

• 14 key numeric pad with decimal

• 16 special function keys

• 8 edit function keys

• 2 block transmission keys

• Self test mode

• Protect mode

• Block mode

• 80 storable tabbing

• Insert/delete character and line

• Scrolling

• Addressable cursor

• A host of other features, including cursor controlsand remote commands such as clear to nulls,spaces, end of line, end of screen; set hi.lo.zerointensity; set blink; etc.

• Optional screen print & 2nd page memory

For our system or for yours, in commercial,technical, educational or personal applications,the Computex X-920 Is unmatched in its class.

All features of the Hazeltine 1400 and ADM-3A

Plus: 128 ASCII characters...

7x 10 matrix... Reverse

video...Print key.,.

Shiftlock... Transparent

mode... Backspace...

Tabbing... Integrated

numeric pad.

$799

List price $956PERKIN-ELMER (Model 550)

Off the shelf delivery now on the Model X-920and P-E Model 550. Add 40 lb. shipping.Customer satisfaction Is guaranteed.

Full refund with the return of any productwithin 10 days. X-9000 CPU $2995. PascalMICROENGINE" owners manual $19.95; X-920operators manual $10, postpaid. Cash prices.10% down guarantees priority. IL residents add5% sales tax. Master Charge and Visaaccepted.

Computex stands for competence. We servicewhat we sell. Written hardware warranty.Nationwide service contracts. Custom software.We provide expert technical support.

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"The Computer Experts"5710 Drexel AvenueChicago, IL 60637

MICROPROCESSOR

BUS

(8 BITS)

Figure Is Block diagram of a microcomputer system that uses an 8-bit microprocessorsuch as the Z80. This system uses bussing techniques that are both multiplexed andbidirectional.

ZSO SIGNALS

M REQ

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-O I/O READ (IN*)

-O MEMORY WRITE (WR*)

I

26 May 1980 © BYTE Publications Inc

Figure 2: Control signals on the Z80 microprocessor. The 7.80 uses a variety of controlsignals to keep data flowing at the right time and in the right direction. Four controlsignals are as follows: the MREQ line goes to a low state (ie: a logic 0) when amemory- reference operation is in progress; the I/OREQ line goes to a low state whenan input/output (I/O) operation is in progress; the RD line goes low when the pro-cessor is reading data from memory or from a peripheral device; the WR line goes lowwhen the processor is writing data to memory or to a peripheral device. The RD andWR signals control the direction that data flows along the bidirectional data bus.Monitoring these four lines gives us all the information necessary to support I/Odecoding functions.

Signals from the four processor control lines are logically combined to form control-strobe signals that perform specific functions. The characters in parentheses give thenames by which the control-strobe signals are known in the documentation for theRadio Shack TRS-80.

Circle 13 on inquiry card. ^~►

COMPARE SMARTS.

livverse vifleo

■ lilinkiiifi/bliink fields

Upper/lower ease char.

Protected fields

. _ I 'mlfrliiiiiifi

_ Ntm-fdure screen

I2,v lOrluir. res,

Hlinkiiifi cursor

• ii timid rates

(7r,iW00 Hmul)

•Self test

Auyiliury port

Function/edit ktys

Typewriier/TTY keyboards

. Numeric pad

Mixtnl 9Z0C shown.

Feature-for*feature our smart CRterminals cost less than their dumbones. Much less. Compare smarts,Then compare price. You'll pick

s to choose

Video, they're standard.

We put a lot of engineering savvyinto our CHI's. Their modular designmeans high reliability, n also lets usbuild in high volume. And sell lo you

k.e your

find out bow you c;next CRT buy a smartTeleVideo today for In

Nationwide Field Service is availablefrom General Electric Co., Instrumen-tation and Communication EquipmentService shops.

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COMPARE PRICE.

ADDRESS

BUS BINARY WEIGHTING TYPICAL PORTSIGNAL CODEN *0 OR 1 LOGIC LEVEL » 27X N ■ 128X1 -- 128 1[>

A3

A2

2" X N ■ 64 X 1 = 64

26 X N = 32X0 ; 0

2* X N ■ 16 X 0

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PORT ADDRESS

HARDWARE DECODERCIRCUIT FOR THAT CODE

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Figure 3a: Various methods can be employed to decode the address signals that appear on the address bus during I/O operations.Here, various inverters and an eight-input NAND gate are hardwired in a configuration that will produce a logic 0 output for one of256 possible I/O port addresses. The logic 0 output can be used to activate the interface for the peripheral device. Here the circuitdecodes the address hexadecimal C5, or decimal 197.

Number

Type

+ 5 V

GND

IC1

74LS85

16

8

IC2

74LS85

16

8

IC3

74LS04

14

7

ADDRESS BUS INPUTA7fZ>

• 6[>

A5f3^

A4C^

A3lZ>

A2£>

Al O-

A0(Z>-

15

OUT

A0 BO

IC1

74LS85

Al Bl

12

14

OUT

74LS85Al Bl

11

J

IC374LS04

h 5V

^>^-o

DECODED ADDRESS

-"LT

1K

TYPICAL FOR 4

-*-"*

-»"V

-*"".-

+ 5V

. 1 K

; TYPICAL FOR 4

-^oJ

^>

SW3

-o^c_

-C'V

It!

Figure 3b: Another method of decoding an address signal. Two 4-bit comparators can be cascaded together to decode an 8-bit ad-dress. The desired 8-bit port address is set up on switches SW8 thru SW1. When the combination of high and low logic states that cor-responds to the desired address appears on the address bus, the output signal produced at pin 2 of IC3 (the 74LS04 inverter) will golow to a logic 0 state. This decoding method allows the port addresses to be easily changed, but the method here is considerably moreexpensive than the decoding method shown in figure 3a. The switches are single-pole, single-throw (SPST) types; an open switchshows logic 1, and a closed switch shows logic 0.

28 May 1980 © BYTE Publications Inc

Circle 14 on inquiry card.

Now! North StarApplication Software!

North Star now offers applicationsoftware for use on the HORIZON!Now you have one reliable sourcefor both hardware and softwareneeds! The first packages avail-able are:

North Word—

NorthWord is a simple-to-operateword processing system designedfor use with the popular North StarHORIZON. NorthWord enables youto increase office efficiency and cutdocument typing time and cost.NorthWord incorporates the mostsought-after word processing fea-tures: easy editing, on-screen textformatting, simultaneous documentprinting, and much more. NorthWordcan be integrated with other NorthStar software packages to producecustomized letters, labels andreports quickly and efficiently.

r*KI

^J

MailManager—

MailManager enables you to com-pile and maintain complete organ-ized mailing lists. Lists are easilyaccessible and can be compiledwith a great deal of flexibility. Entries,corrections and deletions are easilymade. The North Star MailManagercan print your list on individual enve-lopes, on mailing labels, or in com-pact summary form.

InfoManager—

InfoManager is a powerful list-oriented, data management system.It will accept up to 50 categories ofinformation for each record and hasthe ability to select and sort beforeprinting. The North Star InfoManagerhas power and flexibility for manyapplications: product inquiry, in-ventory, customer/client records,calendar reminders, and as an easyway to fill in often-used forms.

GeneralLedger—

General Ledger and FinancialReporting, two programs in one,maintains general ledger accountsbased on such input as checks,bank deposits and journal entries,and uses the information in thegeneral ledger to produce custom-ized financial statements andfinancial reports.

NorthWord is the central buildingblock for all the North Star applica-tion software to follow. Packagesnow being tested include otheraccounting and professional appli-cation packages. For more informa-tion or a demonstration, contactyour local North Star dealer.

NorthSta^

North Star Computers, Inc.1440 Fourth StreetBerkeley, CA 94710(415) 527-6950TWX/Telex 910-366-7001

■t*i^^^'

j?2

f

*

1

&

1

NortftStar

NorthWord

Text continued from page 24:

out that the I/O instructions bear asurprising resemblance to memory-reference instructions. The 6800 and6502 microprocessors actuallyallocate a certain portion of theirmemory address space to be decodedand to function as I/O ports.

This technique, which can be usedon the Z80 and 8080 just as easily, hascertain advantages in speed and ease

of use over direct I/O instruc-tions. This technique is referred to asmemory-mapped I/O. An illustrationof the logic associated with thismethod is in figure 5. For a morerigorous analysis of memory-mappedI/O, I refer you to the November1977 "Ciarcia's Circuit Cellar" articlepreviously mentioned.

The final area for consideration isthe actual transfer of data to and

Number Type +5V GND

IC1 74LS266 14 7

IC2 74LS266 14 7

IC3 74LS30 14 7

74LS266

A5 0-

A4[~2>

JT

SW5 era-

A3[~>

A2(Z>

AlO

JT

SW2 . or o-

A0[>

X

swi ..

tr o-

t^y°y>-

IC274LS266

i^E^i

E>^

0E>

12 i

E>^

.j

D^

-O DECODED ADDRESS

"i_r

Figure 3c: Another method of decoding an 8-bit address, using exclusive-NOR gates andan eight-input NAND gate. As in figure 3b, the desired port address is set up on switch-es SW8 thru SW1.

from the bidirectional data bus. Thecircuits of figure 4 and figure 5 tell on-ly when the I/O operation occurs.Additional logic has to be provided toplace data on the bus during an inputinstruction or to latch and hold thecontents of the data bus during out-put instructions.

When the 8080 or Z80 assemblylanguage instruction OUT (N),D isexecuted, the contents of the ac-cumulator, D, are placed on the databus and written into device N. Thesame is true for the BASIC-languageinstruction OUT N,D. The data is ac-tually valid during only a few clockcycles, perhaps 500 ns. Making thisdata available for longer periods oftime requires the addition of an 8-bitlatch: the latch is made from a set ofclocked flip-flops.

The output lines are attached to thedata bus. When the proper output in-struction is executed, signified by astrobe signal from our address andI/O WRITE decoder circuit asshown in figure 6, the contents of thedata bus are transferred into the 8-bitregister in synchronization with theprocessor clock signal. This combina-tion of circuitry is commonly calledan 8-bit latched parallel output port.

External devices cannot be directlyconnected to the data bus for input,because of the possibility that in-terference and bus-loading problemswill result. A three-state buffer is usedas a gate to allow signals from theperipheral device to be placed ontothe bus at the appropriate time.

During an input operation the pro-cess used for output is reversed.When the proper input sequence is ex-ecuted, signified by the appropriateoutput from the address decoder andI/O READ decoder, the 8-bit three-state buffer is strobed into operationduring the few clock cycles it takesfor the processor to execute the inputinstruction. Logic levels present onthe buffer input lines during that in-stant become impressed onto the databus and are transferred into the ac-cumulator. Figure 6 shows the logicelements that perform these func-tions.

Add Parallel I/O to Your TRS-80

I have been told that the TRS-80Model I is currently the largest-sellingpersonal computer. Unfortunately it

Text continued on page 38

30 May 1980 © BYTE Publications Inc

Gmapihic&

The Paper Tiger puts mare bite into

everything you do.

The Paper Tiger strikes again. With a DotPlot'" graphicsoption that lets you make the most of your Apple II, TRS 80?or other personal computer.

With DotPlot and available software drivers,you can print screen graphics, draw illustrations,write block letters, plot charts. And DotPlotincludes an expanded, 2K-byte buffer.

That's not all. Every Paper Tiger gives you 8software-selectable character sizes. 80 and132 column formats. Multi-part business formshandling. Forms control. Reliable stepper-motor paper drive. Adjustable width tractor feed.Continuous duty cycle operation. Plus lots more.

fApple II is a trademark of Apple Computer Inc.

^TRS-eo is a trademark of Radio Shack, a division of Tandy Corp.

I

The Paper Tiger costs only $995. The DotPlot option only$99 more. But don't let these low prices fool you. Because thePaper Tiger is rugged enough to stand up to themost demanding printer-plotter requirements.:mm For the name of the Paper Tiger dealer nearest

J you, call toll-free 1-800-343-6412 (except Massa-chusetts, Alaska, and Hawaii).«■ Integral Data Systems, 14 Tech Circle,

Natick, MA 01760. (617) 237-7610.

ftj^\ Circle 15 on inquiry card.

^C-/Integral Data Systems, Inc.

Circle 16 on inquiry card.

GET IT

OFF THE

FLOOR

Now that you have a shiny newcomputer terminal, what are yougoing to put it on? Computer Furni-ture and Accessories makes a varietyof furniture for a wide range of com-puter applications. In combinationsof six widths, three depths, and threeheights. With "L" shaped returns,Micro shelves, data shelves, RETMAmounting, and printer stands. Withoptional drawers, doors, CRT turn-tables, and casters. Sizes, shapesand colors designed to fit your officeor computer room environment. Rea-sonably priced and shipped fromstock.

Call CF&A. We'll get your system upwhere you can really put it to use.

CF*A

Computer Furniture and

Accessories, Inc.

1441 West 132nd Street

Gardena, CA 90249

(213) 327-7710

A15 0>-A14 [Z>-A13 LZ>"A12 0-All O

A10 CZ>-

A9 O"A8 £>"A7 O-

A6 O"

A5 o-

A4 rz>-

NOT USED FORI/O APPLICATIONS

8 BIT LATCHED PARALLELOUTPUT PORT

00000000

ADDRESS DECODINGSET FOR PORT 7

4>M

>

A3 LZ>A2 O-

>

o-

Al [Z>-

ao n>-

8 BIT REGISTER

LATCH Dll THRU DI8

./° 74LS30

^ ,. 74LS32

OUT

I/O WRITE C>-STROBE

ECODEDTPUTSTROBE

Figure 4a: Block diagram of a typical parallel output port. The logic that decodes the8-bit port address was shown in three forms in figure 3. The signal from the address-decoding, circuit is logically combined with one of the control signals from figure 2 (I/OWRITE) to produce an output strobe signal that activates the 8-bit output latchregister.

A15

A14

A13

A12

All

A10

A9

A8

A7

A6

A5

A4

A3

A2

Al

AO

o-

o-

o-

\z>-o-o-o-

o-

NOT USED FORI/O APPLICATIONS

8 BIT STROBED PARALLELINPUT PORT

t>

{,

ADDRESS DECODINGSET FOR PORT 7

>

t>

8 BIT

THREE-STATE BUFFER

STROBE DOl THRU D08

74LS30

*_ ^ 74LS32 "L-T

*r*~ . J ^/ DECODED

IN

I/O READSTROBE

o-

INPUTSTROBE

1

i

Figure 4b: Block diagram of a typical parallel input port. Note the resemblance to theoutput port of figure 4a.

32 May 1980 © BYTE Publications Inc

Circle 17 on inquiry card.

Color communicates better. That's the obvious benefit ofISC's new CP/M®compatible desktop computer.

What isn't as obvious is how easy it is to operate the Intecolor®8963. Because the CP/M operating system lets you choosefrom an abundance of prepared CP/M business software, youdon't have to write programs unless you want to. And with ISC'scolor-coded word processing program, you can take advantageof the 8-color graphics display immediately! Color-enhancedprograms are also available from Peachtree Software* to handleyour General Ledger, Accounts Receivable and Payable, Payroll,Mailing List and Inventory Management System.

The Intecolor 8963 is complete with 19" CRT display, 32Kof user RAM (now expandable to 64K), 591K dual 8" floppy diskdrive and a color version of Microsoft® Business BASIC. Atjust $6395+ it's perfect for the small business.

If you'd rather get down to business than write programs,ask for a demonstration of the Intecolor 8963. Available atselected computer dealers, or contact your nearest ISCsales representative.

L,L,I IlL.L, ....,!.,,». |ll..

tU.S. domestic price.

Unretouched photo of screen.

CP/M is a registered trademark of Digital Research Corp.

*TM Retail Sciences, Inc

ISC SALES REPRESENTATIVES: AL: 205 883-8660. AZ: 602/994-5400, AR: (TX) 214/661-9633. CA: Alhambra 213/261-2280. Goleta 805/964-8751, Irvine 714/557-4460. Los Angeles 213/476-1241. Los

Alios 415/948-4563. San Diego 714/292-8525, CO: 303/355-2363. CT: 203/624-7800. DE: (PA) 215/542-9876, DC: (VA) 703/569-1502, FL: Fl. Lauderdale 305/776-4800. Melbourne 305/723-0766. Orlando

305/425-5505. Tallahassee 904/678-6642. GA: Allanta 404/455-1035, HI: 808/524-8633. ID: (LIT) 801/292-8145. IL: (No.) 312/564-5440, (So. MO) 816/765-3337. IN: (IL) 312/564-5440, IA: (Scott County

Only) 312/564-5440. (MO) 816 765-3337. KS: (MO) 816/765-3337. KY: 606/273-3771. LA: 504/626-9701. ME: (MA) 617/729-5770. MD: (VA) 703/569-1502, MA: 617/729-5770, Ml: Brighton 313/227-7067.

Grand Rapids 616/393-9839, MN: 612/645-5816, MS: (AL) 205/883-8660, MO: 816/765-3337, MT: (CO) 303/355-2363. NB: (MO) 816/765-3337. NH: (MA) 617/729-5770. NJ: (No.) 201/224-6911. (So.)

215/542-9876. NV: (AZ) 602/994-5400. NM: 505/292-1212. NY: Melro/LI(NJ) 201/224-6911. N. Syracuse 315/699-2651, Fairport 716/223-4490, Ulica 315/732-1801. NC: 919/682-2383. ND: (MN)

612/645-5816. OH: Cleveland 216/398-0506. Daylon 513/435-7684. OK: (TX) 214/661-9633. OR: 503/644-5900, PA: (E) 215/542-9876. (W) 412/922-5110, Rl: (MA) 617/729-5770. SC: 803/798-8070, SD:

(MN) 612/645-5816. TN: 615/482-5761. TX: Auslm 512/454-3579. Dallas 214/661-9633, El Paso Area (Las Cruces. NM) 505/524-9693. Houslon Only 713/681-0200. UT: 801/292-8145, VT: (MA) 617/729-5770,

VA: 703/569-1502. WA: 206/455-9180. WV: (PA) 412/922-5110. Wl: (IL) 312/564-5440. WY: (CO) 303/355-2363,

EUROPEAN EXPORT SALES: EUROPE: (MA) 617/661-9424, BELGIUM: Brussels 02-242-36-04, DENMARK: 02-913255, FRANCE: Rueil Malmalson 749-47-65, Paris 33-1-306-4606, GREECE: Athens

642-1368. ITALY: Milano 02600733. THE NETHERLANDS: Poeldi|k 01749-47640. Amslerdam 020-360904. SPAIN: Barcelona 204-17-43, SWEDEN: Vallingby 08-380-370, SWITZERLAND: Mutschellen

057-546-55. UNITED KINGDOM: Bournemouth 0201671181. WEST GERMANY: Koblenz 01149-31025/6. AUSTRALIA & NEW ZEALAND: Auckland 876-570. Canberra 58-1811. Chermside 59-6436.

Chnslchurch 796-210. Melbourne 03-543-2077. Sydney 02-808-1444. Wellington 644-585, CANADA: Dorval 514/636-9774, Ollawa 613/224-1391. Toronto 416/787-1208, Vancouver 604/684-8625, CENTRAL

AND SOUTH AMERICA & CARIBBEAN: (GA) 404/394-9603, MEXICO: Monlerrey 564-876, FAR EAST: (CA) 213/382-1107. HONG KONG: 5-742211. JAPAN: (Tokyo)

(03) 463-9921. TAIWAN: (Taipei) 02-7026284, MIDDLE EAST: (GA) 404/581-0243, EGYPT: 809933. ISRAEL: Ramal Gan 03725749.

KUWAIT: Kuwail 438-180/1/2. LEBANON: Beirut 221731/260110, SAUDI ARABIA: Jeddah 27790. Riyadh 25083-39732.

For sales and service in other countries contact ISC headquarters in Norcross. GA.. U.S.A.

intelligent Systems Corp.

Intecolor Drive • 225 Technology Park/Atlanta • Norcross, GA 30092 • Telephone 404/449-5961 • TWX 810-766-1581

I/O WRITE O-

=o

12

I/O READ O-

ADDRESSBUS

A7 C>-A6|^^-A50-

A30-

74LS30

o

74LS32

Di

A2 O"Al[3^

A0[>

74LS*2

4 TO 10DECODER

15}

NOT USED

-Q>P0RT FF

-OP0RT FE-C>P0RT FD

-O>p0"T FC-O>P0RT FB

-Oport FA

"OPORT F9

-Oport fs

8 DECODED) OUTPUTSTROBES

741S42

4 TO 10DECODER

9 —

10

}"

OT USED

-£3>P0RT FF"-O>P0RT FE

-Oport fd-Oport fc-Oport fb-Oport fa-C>port F9-C^>port F8.

8 DECODED

}INPUT

STROBES

Figure 4c: Schematic diagram of a circuit that produces eight decoded input-strobe signals and eight decoded output-strobe signals.The port addresses produced are hexadecimal F8 thru FF. Circle 18 on inquiry card

pencil, a cara, anit's the new, fast way to enter data into yourmicrocomputer."

Interfaces to TRS-80, Apple II, PET, and others.

Good news! Now, all you need is a standard #2 pencil, a card, and our newMR-500 mark sense card reader to quickly and easily enter data into yourfavorite microcomputer.

As Easy as One, Two, Three...

Here's all you have to do. One — program the card by marking with the pencil.Two — feed the card into the reader slot. Three — the reader automatically turnson, the card is fed through, and data is instantly entered into memory. It's thesimple low-cost alternative to keyboard data entry.

For Educators, Small Businessmen, and...

The applications for our low-cost MR-500 are endless. For small businesses, it'sideal for inventory, time cards, labor distribution (just to name a few). Educatorswill find that the MR-500 streamlines test scoring, attendance records, and gradereporting. Bet you can find a use already.

The Small Reader for the Small Computer

The MR-500 is lightweight-4 lbs. Compact- ^^^^^ Phone or write

a 4'/2-inch cube. And at $750, it's the only mark j^k [ for details.

sense card reader that makes sense for the Ir^a^^ I °r better vet*

small computer. I I order yours today.

«*hk

"Hot,

CHATSWORTH DATA

i aivi

20710 Lassen Street • Chatsworth, California 91311(213)341-9200

Combine the POWER of PASCALwith the MUSCLE of your MICRO!Get the tool to do your job right:

RASCAL/MT ® 3.0

Compile in32K CP/M®!SYMBOLICDEBUGGERINCLUDED

Industrial features:

Bit, byte S. stringmanipulation.

Floating Point math.

Interrupt procedures.

8085 Support.

Inline assembly code.

Multiple HEAPs.

AMD 9511 support.

Note: Both compilers areexactly the same exceptfor REAL implementation.

Complete System

for

$250

Includes all these items:

• 95 Page User's Guide

• Industrial/Scientific Compiler[Floating Point]

• Commercial Compiler[18 digit BCD]

• Source code for run-time library

• Pascal/MT Library inPascal source

• Interactive SymbolicDebugging Package

ROMABLE8080/Z80

CODE!

MINIMUM

OVERHEAD

1280 Bytes!

Commercial features:

18 digit BCD REALs.

Program chaining.

CP/M® sequential andRANDOM Re I/O.

User formattingroutines.

Dynamic Strings.

Multiple HEAPs.

Printer Support.

Note: BCD Reals are 18digits with 4 fixed decimalplaces.

Manual available separately for $30, refundable with system order

VISA

/ MT MicroSYSTEMS \

1562 Kings Cross DriveCardiff, CA 92007 [714] 753-4856

We ship on 8" single density disks

OTHER DISK FORMATS: LIFEBOAT ASSOC [212] 580-0082, FMG [TRS-80] [817] 294-2510

® CP/M tradename of DIGITAL RESEARCH PASCAL/MT trademark of MT MicroSYSTEMS

Circle 19 on inquiry card.

BYTE May 1980 35

<WR*1MEM WRITE O

A15 £!>-AH[>A 13 O-A12 O-AllOA10 LZ>"A9 C>-

A8 0>-

A7 £>-

A6 O-

A5 O-

A4 O-

A 3 O-

A2 0>-

Al O"

AO O-

(RD*)

MEM READ O-

74LS04

->"

74LS30

3^^

74LS20

4>-

3^*

PORT FFFE'OUTPUT STROBE

i>-

PORT FFFE' INPUT STROBE

Figure 5: Memory-mapped input and output. Some microprocessors do not have specific input and output instructions. In systemsthat use such microprocessors, the I/O port hardware is wired as a memory location; I/O operations take place using the memory-reference instructions (eg: load-into-accumulator and store-in-memory instructions) of the microprocessor. This type of addressing iscalled memory-mapped I/O, and all sixteen lines on the address bus must he decoded to perform an I/O operation.

Number

Type

+ 5 V

GND

IC1

74LS377

20

10

IC2

74LS244

20

10

IC3

7404

14

7

LATCHEDPARALLEL OUT

PARALLEL INPUT

DECODEDOUTPUT Q>-STROBE -, ~

DATABUS

D7|3^D6 O"D5 \Z>-D4 G>"D3 O-D2 0Dl O"DO O-

IC37404

IfrJ—U

JT

8 BIT REGISTER

B7 B6 B5 B4 B3 B2 Bl B0

B7 B6 B5 B4 B3 B2 Bl B0

00000000 vwvvwv

2 5 6 9 12 IS 16 19

1Q 20. 3Q 4Q 5Q 6Q 7Q 8Q

CK

IC174LS377

G

ID 2D 3D 4D 5D 6D 7D 80

13

14

17

Al A4 A2 A3 A3 A2 A4 Al

1GIC274LS244

2G¥1 Y4 Y2 Y3 Y3 Y2 Y4 Yl

18

18

19

DECODED-<ZJ INPUT_ _ STROBE

8 BIT THREE-STATEBUFFER

-O D7-O D6

-O D6-O D4

-O D3HZ>D2

■Odi

-O DO

Figure 6: Data connections in input and output ports. Once the proper port address has been decoded and combined with the read- orwrite-control signal to form an I/O strobe signal, the actual process of accessing the data bus for data transfer is relatively easy.

For input to the accumulator (the most common pathway for I/O), a three-state buffer is used in conjunction with the decodedinput-strobe signal that controls the enable line of the buffer.

For output from the accumulator, an 8-bit latch is connected to the data bus. During the execution of the output instruction, thecontents of the data bus are clocked into the latch register and are latched there by the output-strobe signal.

36 May 1980 © BYTE Publications Inc

Circle 20 on inquiry card.

people

who play the

computer

specify

\ferbatinr

Virtuoso performers atcomputer keyboards deservethe ultimate in recordingquality. That's why youshould specify Verbatimbrand diskettes, minidisks,cartridges and data cassettesfor your computer or wordprocessing system.

At Verbatim, the whole mes-sage is quality. We specializein digital data recording mediaand have become the worldleader by setting the standardsfor flawless, dropout-freemagnetic media. Every size,every format, and availableeverywhere. Order them from

your computer supplies dealer.Simply specify Verbatim.

For the name of your nearestVerbatim distributor, call:

800-538-1793

In California call:

(408) 72,7-7771 collect

Verbatim Corporation323 Soquel WaySunnyvale, CA 94086

In Europe:

Verbatim S.A.

Case Postale 296

1215 Geneve 15

Switzerland

Telephone: 41(22) 34-90-55

Telex: 22647 ITCE CH.

See us at NCC, booth 1228-1234

r~

I

Number

Type

+ 5 V

GND

IC1

74LS125

14

7

IC2

74LS125

14

7

IC3

74LS75

5

12

IC4

74LS75

5

12

IC5

74LS155

16

8

IC6

74LS04

14

7

IC7

74LS04

14

7

IC8

74LS30

14

7

Text continued from page 30:is not configured to be easily inter-faced to the projects I present eachmonth. The widely sold Level IIBASIC, 16 K-byte memory versionhas no parallel I/O capability, asidefrom the single-bit cassette-motorcontrol. With the addition of the ex-pansion interface, the user gets one

parallel output port and one half (ie:4 bits) of an input port. If these portsare used, as Radio Shack intends, todrive a printer, then the only way toprovide usable parallel I/O capabilityis to add a separate I/O interface.

Considering the pertinent elementsof the previous discussions, it is easyto construct both parallel input and

TRS-80

EXPANSION

CONNECTOR

D7 f5(P>-

D5HjT>-D4|~J1P>-D3r26^D2[32^^Dl [22^>-DO [30^

IN* [TT>-OUT* [T2^>—

>5|~35^

A4[31^

A3 [34^>-

A2f!(P>-

Al[27>

Aoiinr

IC774LS04

J|>8.

I ice ~~1

74LS04

^

\_

V

PL

VJ

V

*fc*

^v

15

IC874LS30

o

1C

2C I

IC574LS155

1G2G

01

I

N#l

0UT#1

IC174LS125

1C 2C 3C 4C

10

13

1C 2C 3C 4C

1Y

2Y

3Y

4Y

IC274LS125

IC7

74LS044

IC374LS75

ID2D3D

4D

1Q2Q

3Q

4Q

13

13

ID2D3D

4D

1Q2Q3Q

4Q

IC474LS75

15

<Z]B6

<^B3

<]B2

-OB4

PARALLEL

INPUT

} OUTPUTPORT

-OB3

-0*2^>B1

Obo|

Figure 7: A complete, economical, parallel I/O interface circuit for use with the Radio Shack TRS-80 computer, or with other com-puters that use a similar bidirectional data bus. This interface can be connected directly to the expansion connector at the rear of theTRS-80 keyboard/processor unit, or it can be connected through the expansion-interface unit. As the circuit is shown here, there aresix presently undefined additional strobes available on IC5. These six strobes can be used to support three additional ports. Refer tofigure 3 and figure 4 to determine the proper selection of the I/O port address for this interface.

38 May 1980 © BYTE Publications Inc

Circle 21 on inquiry card.

for the...

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^a^.^m

viss\

[master charge

parallel output ports for the TRS-80.The interface shown in figure 7 pro-vides one input and one output port.The signals necessary to drive this in-terface are available on the forty-pin

expansion connector of the key-board/processor unit or on connectorJ2 on the expansion interface. Ineither case, a separate +5 V supply isnecessary to power the circuit. The

Pin

Signal

Number

Name

Description

1

RAS*

row-address strobe output for 16-pindynamic memories

2

SYSRES*

system-reset output, low during power-up initialization or when the reset switchis depresssed

3

CAS*

column-address strobe output for 16-pindynamic memories

4

A10

address output

5

A12

address output

6

A13

address output

7

A15

address output

8

GND

signal ground

9

A11

address output

10

A14

address output

11

A8

address output

12

OUT*

peripheral-write strobe output

13

WR*

memory-write strobe output

14

INTAK*

interrupt-acknowledge output

15

RD*

memory-read strobe output

16

MUX

multiplexer control output for 16-pindynamic memories

17

A9

address output

18

D4

bidirectional data bus

19

IN*

peripheral-read strobe output

20

D7

bidirectional data bus

21

INT*

interrupt input (maskable)

22

D1

bidirectional data bus

23

TEST*

placing a logic 0 on this line causes ahigh-impedance condition on addresslines AO thru A15, data lines DO thru D7,WR*, RD*, IN*, OUT*, RAS*, CAS*, andMUX

24

D6

bidirectional data bus

25

AO

address output

26

D3

bidirectional data bus

27

A1

address output

28

D5

bidirectional data bus

29

GND

signal ground

30

DO

bidirectional data bus

31

A4

address bus

32

D2

bidirectional data bus

33

WAIT*

processor-wait input, to allow for slowmemory

34

A3

address output

35

A5

address output

36

A7

address output

37

GND

signal ground

38

A6

address output

39

on Level I machines: low-current +5 V

output

on Level II machines: no connection

40

A2

address output

Table 1: Description of function for the pins on the expansion port at the rear of

the TRS-80 keyboard/processor unit. This pin assignment is also used in expan-

sion slots in the expansion-in

terface unit. This information is provided through

the courtesy of Radio Shack,

a division of Tandy Corporation.

11 13 15 17 19 21 23 25 27 29 31 33 35 37 39

8 10 12 14 16

18

20 22 2*

-cj—ar26 28

30 32 34 36 38 40

Figure 8: The configuration of output pins on the expansion port on the rear of theTRS-80 keyboard/processor unit. See table 1 for an explanation of the function of eachpin.

signals on the expansion connectorare listed in table 1, and the pinoutsare shown in figure 8.

The schematic diagram of figure 7shows a port address FF. To setanother port address simply refer tofigure 3 and 4 and place the switchesfor the proper code.

There are many other methods forimplementing I/O capability. An8255 programmable peripheral inter-face, a parallel I/O device, couldhave been used. The circuit I have

I hope to enable manyTRS-80 owners to buildthis I/O circuit and to useit to attach other "CircuitCellar" projects to theircomputer systems.

chosen to present is intended to be in-expensive and easy to operate. Byminimizing potential parts-acquisi-tion problems and keeping down thesoftware handshaking necessarywhen using large-scale circuits likethe 8255, I hope to enable manyTRS-80 owners to build the circuitand use it to attach other "CircuitCellar" projects to their computersystem.

Those experimenters who hesitateto build hardware might want to pur-chase the entire communications in-terface. An assembled and testedunit, with power supply and contain-ing a parallel port (for the Centronicsprinter) and a serial RS-232C-compatible interface, is available.The complete communications unit,called the COMM-80, will bepresented in part 2 of this article andis available for $179.95 from:MicroMint Inc917 MidwayWoodmere NY 11598Telephone (513) 374-6793(New York residents please add ap-plicable sales tax.)

Next Month

/ shall complete the COMM-80presentation by discussing the con-struction of a software-compatibleRS-232C interface for the TRS-80 thathas selectable data rates from 50 to19200 bps.m

40 May 1980 © BYTE Publications Inc

Circle 22 on inquiry card.

APPLE '

ALTOS •

LSI-11 •

tB&$K\

S-100 BUS

TRS-80MODEL 1

MODEL 2

Now you can transform your personal computer into a multi-usersystem for business or educational applications. From two tosixty-four computers can be linked together sharing up to 40million bytes of Corvus hard disk capacity.

A true multi-processing system, the CONSTELLATION™ pro-vides open or secured access to all data files on the Corvus diskdrive. Additional benefits include the ability to share peripheralsand communicate with other computers in the CONSTELLATIONnetwork. Providing performance usually found in much moreexpensive systems, the price of the CONSTELLATION multiplexeris only $750. Interfaces for additional computers are as low as $235.

The CONSTELLATION is another innovative new product in thegrowing family of intelligent peripherals from Corvus. Our 10million byte disk drives, MIRROR™ back-up/archival storagesystem, and now the CONSTELLATION, are all fully compatiblewith the most popular microcomputers available today: APPLE*(DOS and Pascal), TRS-80** (Model I & II), S-100 BUS, LSI-11,and ALTOS. Our Z-80 based intelligent controller handles up tofour 10 million byte Winchester disks of proven performance andreliability—the IMI-7710.

Corvus—recognized leader in intelligent peripherals for micro-computers—provides solutions, not just hardware.

For complete information call or write Corvus today.

' Trademark of Apple Computers, Inc.' Trademark of Radio Shack, a Tandy Co.

Corvus CONSTELLATION photo courtesy Science Graphics, Tucson, Ariz.

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KIMDOS

Using Your KIM-1 with aPercom Floppy-Disk Drive

Joel Swank

4655 SW 142nd Apt 186

Beaverton OR 97005

Any owner of the MOS Techno-logy KIM-1 knows the utility of theKIM's built-in audio-cassette inter-face. But, any KIM-1 owner who hasexpanded his system knows just aswell how inappropriate the cassette isfor storing long files. The standardKIM cassette format is intolerablyslow, and even using the Hypertapemethod (a faster cassette-storage for-mat for the KIM), a 4 K-byte filetakes a minute and a half to load, notcounting the time needed to positionthe tape.

The natural storage alternative is,of course, the floppy disk. However,there are some difficulties. A floppy-disk system requires a considerableamount of software to make it useful.In addition, many floppy-disksystems available today come withproprietary software for the8080/Z80 or 6800 processors. Inter-facing such systems to a KIM-1 re-quires the hobbyist to write his or herown 6502 software, working from themachine code for the other processor.While it is possible to do this, fewhobbyists are willing to translatemachine code to get their disk systemup and running.

I decided to interface a PercomLFD-400 disk system to my KIM-1.The LFD-400 system contains a diskcontroller capable of controlling upto three 5-inch floppy-disk drives. Itcomes with complete, annotatedsource code for the 1 K-byteMINIDOS disk-operating system,written for the 6800 processor.MINIDOS allows the reading andwriting of contiguous memory files,and is the nucleus of MINIDOS-

PLUSX, a 6800-based disk-operatingsystem sold by Percom.

KIMDOS is a KIM-1-compatibleversion of the Percom MINIDOS. Itallows a KIM-1 to read and write filesthat are compatible with the Percomformat. This article will concentrateon explaining the workings of theKIMDOS software. The LFD-400system easily interfaces to the buslines of any KIM-1 system (see table1); because of this, hardware inter-facing will not be discussed here.

The LFD-400 uses hard-sectored

disks with ten 256-byte sectors pertrack and thirty-five tracks per disk.This gives 87.5 K bytes of usabledata per disk. The controller boardhas sockets for up to 3 K bytes of2708-type erasable programmableread-only memory (EPROM).KIMDOS has been written to fit inone 2708 device.

The controller board requiresunregulated power supplies of+ 14 V, -14 V, and +8 V; orregulated power supplies of +12 V,— 5 V, and +5 V. The controller is

Photo 1: The author's personal computer system. It contains the following commercial-ly built equipment: a MOS Technology KIM-1 microcomputer, three 8 K-byte DigitalGroup static memory boards, a Percom LFD-400 floppy-disk controller and twoShugart 5-inch floppy-disk drives, a Southwest Technical Products CorporationGT-6144 graphics board, an ACT-IA terminal with Leedex monitor, an Olivetti TE-300hard-copy terminal, and several Lambda power supplies. Homebrew equipment in thesystem includes a programmer for erasable programmable read-only memories(EPROMs), a programmable integrated-circuit tester, a calculator interface, the mother-board, and the input/output (I/O) interface board.Photograph taken by John M Hannam.

44 May 1980 © BYTE Publications Inc

For years many small business system buyersthought that in order to get "real" performanceand enough storage to be a "real" business systemthey would have to sacrifice the family jewels.

But with the introduction of the Smoke SignalChieftain series office computers a lot of people'sminds have been changed.

Because we designed the highly reliableChieftain small business system with the mostinnovative combination of performance and effi-ciency around.

At your fingertips there are 64,000 charactersof random access memory and you can addressanywhere from 740,000 characters to 2 millioncharacters with Smoke Signals's new double den-sity controller. For larger concerns, there's a 20Mbyte hard disk available.

At a time when other small computer manu-facturers tell you "you're on your own", SmokeSignal offers an abundance of easy-to-use softwareprograms such as order entry, inventory control,

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

Chieftain systemsstarting at under $200.00per month display per-formance on par with sys-tems costing twice tothree times as much.

So call (213) 889-9340for your nearest autho-rized Smoke Signal dealerdemonstrate the Chieftain's high reliability andease of operation For dealers onlyi circ|e 25

All other inquiries, circle 24

he'll be glad to

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composed of twenty-seven transistor-transistor logic (TTL) integrated cir-cuits and the Z5023 universal syn-chronous receiver/transmitter(USRT) on a 15.24 by 25.4 cm (6 by10 inch) two-sided printed-circuitboard. Low-power Schottky (LS)components are used to reduce powerconsumption and minimize busloading.

Floppy-Disk Drive

The Shugart 5-inch floppy-diskdrive comes assembled and testedfrom Percom. A copy of the Shugartinstruction manual is included in thesystem documentation; it is thirty-three pages long, and containsschematic diagrams and completespecifications for the drive and itsoperating principles. Trouble-shooting procedures are also detailed.

Each disk drive must be set up torespond to a specific drive number.This programming is accomplishedby plugging a shunt block into afourteen-pin dual-in-line pin (DIP)socket. A seven-pole DIP switch canreplace the shunt block; the drivenumbers may be easily changed usingthe switch.

Because the Shugart floppy-diskdrive allows only three drive-selectlines, the controller board in the Per-com LFD-400 system uses only thedrive-select lines that are numbered01 thru 03. A drive-select line fordevice 00 exists, and can be selectedby the KIMDOS software; however,this line is not usually -connected toanything. With the addition of theproper jumpers to the controller anddisk-drive boards, a four-drive disksystem can be configured using devicenumbers 00 thru 03. The Micropolisdisk drive could be used for this pur-pose, since it has a fourth drive-selectline on pin 34 of the thirty-four-pinribbon cable.

Functions of the Controller

The LFD-400 uses a crystaloscillator to time the data and clockbits from the drive. The data isseparated from the clock bits and isshifted into the universal syn-chronous receiver/transmitter. TheUSRT latches each 8-bit byte and setsa flag to notify the processor to readthe byte. For a write operation, theUSRT sets a flag when it is ready toreceive data from the processor. Afterthe processor has stored the data inthe USRT, the data is shifted out,

LFD-400

(

KIM

Connector

Function

Comments

9

E-7

RST

10

E-V

R/W

11

E-22

VMA

VMA always true on KIM-1

12

E-U

<t>2

19

+ 14 V

or use regulated + 12 V

20

-14 V

or use regulated -5 V

21

+ 8 V

or use regulated +5 V

22

+ 8 V

23

+ 8 V

24

E-22

ground

25

ground

26

ground

27

E-A

A0

28

E-B

A1

29

E-C

A2

30

E-D

A3

31

E-E

A4

32

E-F

A5

33

E-H

A6

34

E-J

A7

35

E-K

A8

36

E-L

A9

37

E-M

A10

38

E-N

A11

39

E-P

A12

40

E-R

A13

41

E-S

A14

42

E-T

A15

43

E-8

D7

44

E-9

D6

45

E-10

D5

46

E-11

D4

47

E-12

D3

48

E-13

D2

49

E-14

D1

50

E-15

DO

Table 1: Hardware

connections from the

KIM-1 single-board computer to the

Percom LFD-400 disk-drive con

troller. Also given is the function of each line us-

ed.

merged with the clock bits, and is sentto the drive.

The controller also takes care ofmaintaining the current sector count.The motor-control circuit contains amonostable multivibrator (common-ly called a one-shot) that turns themotor off after about 3 seconds ofnonuse. The drive select is a 2-bitnumber that is latched and decodedto select one of three drive-selectlines, as discussed previously. Thedrive-select line for device 00 is notused. The step and direction bits arealso latched. The track-0 and thewrite-protect lines are buffered forthe microprocessor. Address de-coding is provided for all controlleraddresses and for the 2708s. The databus is buffered with 8835 three-statebuffer devices.

Hardware Modifications

The only incompatibility betweenthe KIM-1 and the LFD-400 lies withthe use of a "low-true" logic conven-

tion on the SS-50 data bus. In thelow-true convention, a voltage poten-tial of 0.4 V or less is regarded as atrue or binary 1 logic signal. Thisconvention is used because the 8835devices are inverting buffers.

The KIM-1 uses a high-true con-vention on its data bus; potentials of3.5 V or greater are regarded as atrue or binary 1 logic condition. Toremedy this problem, I replaced the8835 buffers with their noninvertingcounterparts, 8833 buffers. Since thedisk-controller board does not havesockets, the 8835s had to be un-soldered. An alternative methodwould have been to write softwarethat accepts and translates the in-verted data coming from the con-troller, but the software methodseemed more difficult and error-prone than the hardware method ofreplacing the three-state buffers.

My KIM-1 system has regulatedvoltage sources of +5 V, —12 V,and +12 V. I chose to bypass the

46 May 1980 © BYTE Publications Inc

Z8000 IEEE S-100Board $495

Z80 Emulator $250(with purchase of Board)

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Circle 47 on inquiry card.

BYTE May 1980 83

New easy-to-use educational module.

Itfour best ticket to the microprocessor world.

Ideal for teaching.lfourself. Or others.

TI's new TM990/189 University Moduleis a stand-alone learning lab. Fully as-sembled and designed for maximumhands-on experience. To ease and sim-plify learning and teaching.

Outstanding features include power-ful 16-bit microprocessor with easy-to-learn, easy-to-use minicomputerinstruction set; 45-key alphanumerickeyboard and ten-digit seven-segmentdisplay for easy assembly-languageprogramming; ROM-resident softwareincluding system monitor for programdebug and symbolic assembler; audiocassette interface; easy-to-add EIAand TTY interface; lK-byte RAM ex-pandable to 2K; 4K-byte ROM and2K-byte expansion EPROM socket;16-bit programmable I/O controller;

user addressable LEDs, and soundindicator.

A 570-page tutorial text accompaniesthe module. It is a detailed guide forself-paced learning. Or the basis for a

OPTIONAL ACCESSORIES

TM990/189 Kit K1

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An I/O expansion kit that provides the fol-lowing options to TM990/189:

1. Asynchronous Communication port

2. On-board relay for audio cassetteinterface

3. Off-board CRU expansion

TM990/189 Kit K2 $34.00*

A RAM expansion kit that will double on-board RAM from 1K bytes to 2K bytes.

•U.S. prices, subject to change without notice.

three-hour university course. Chaptersinclude an overview of microprocessors;programming exercises; assembly lan-guage; memory systems; I/O conceptsand designs; software engineering;product development; a variety of labexperiments, and much more. Also withthe module: a 300-page user's guide.

The University Module complete withtutorial text and user's guide isonly $299.00.*

To order your University Module

contact your nearestauthorized TI distributor.For more information,write Texas InstrumentsIncorporated, RO. Box1443, M/S 6404, Houston,Texas 77001.

Fifty Years

, ofInnovation

'Br

Circle 26 on inquiry card.C 1980 Texas Instruments Incorporated

Texas Instruments

1 NCORPORATED

85577A.

LFD-400 regulators for +5 V and+12 V and drive the circuits that re-quire these voltages directly from thesystem power supply. I fed the— 12 V source into the —5 Vregulator on the LFD-400 to obtainthat regulated voltage.

The only other modification re-quired was due to a problem with theoscillator circuit, which did notalways start when the system waspowered up. To correct this, I short-

circuited the 0.001 jtF capacitor nearthe crystal, effectively removing itfrom the circuit. According to theengineers at Percom Data Corpora-tion, no one else has reported thisproblem.

There are five ten-pin Molex con-nectors on the controller board.Mates for these are available fromPercom; however, it may be moreconvenient to simply remove the Mo-lex connectors and replace them with

2a

HexadecimalAddress

ccoo

Function When Used as Input

CC01

CC02

CC03CC04

2b

Read USRT status:

bit 0 = 1 means disk unit ready to send byte to computerat address CC01 during read operation

bit 7 = 1 means disk unit ready to receive byte from computerat address CC01 during write operationAddress used to transmit data from disk drive to computer during readoperation

During read operation, bits 0 thru 3 contain current sector number inbinary

Drive status byte : see table 2b.

Accessing this location with a load instruction (LDA) causes a readoperation to take place

Bit Value0

Meaning

1 Write-protect notch in diskcovered; disk is pro-tected

1 1 Head is at track 0

2 0 Drive motor is on

3 0 Drive circuit is ready to

write to disk

4 1 Sector pulse; drive detects

sector hole

5 1 Index pulse; drive detects

special index hole6,7 Binary number of drive

selected (01 thru 03)

Table 2: Memory addresses used bythe LFD-400 disk-controller board.Communication takes place betweenthe disk and the computer viamemory-mapped bytes as listed. Table2a gives the function of 5 bytes usedfor input from disk to computer. Table2b defines the permissible values of bitsin the drive-status byte (hexadecimallocation CC03). Table 2c gives thefunction of 7 bytes used to control out-put from the computer to the disk.

2c

HexadecimalAddress

CCOO

CC01

CC02

Function When Used as Output

Defines value that controller will recognize as the SYNC byte at thebeginning of a read operation; hexadecimal FB used in Percom formatAddress used to transmit data from computer to disk unit during write

operationDefines value that controller will recognize as the filler byte (writtenafter trailer until disk motor turns off); hexadecimal FF used in thissoftwareCC03 Data to select drive and head-movement direction:

bit 4 = direction of head movement: 1 =in, 0 = outbit 5 = step pulse bit; causes data-transfer head tojump to next track in direction given by bit 4bits 6, 7 =binary number of drive to be selectedCC04 Accessing this location with a store instruction (STA) causes a write

operation to take placeCC05 Accessing this location with either a load (LDA) or store instruction

causes a motor-on pulse to be sent to the disk driveCC06 Accessing this location with either a load or store instruction causes a

motor-off pulse to be sent to the disk drive

another type. The pin numbers on thecontroller board and the KIM-1equivalents are given in table 1.

Software and HardwareInteraction

All communication between themicroprocessor and the disk con-troller takes place through hexa-decimal memory addresses CCOOthru CC06. Because address lines A4thru A9 are not decoded, addresses aslow as hexadecimal CC10 to CC16and as high as hexadecimal CFF0 toCFF6 also respond identically; butthese addresses are not used. A com-plete list of controller addresses andfunctions is found in table 2.

The data on each floppy disk isarranged in thirty-five tracks or con-centric circles. The motor rotates thedisk at 300 rpm — one rotation takes200 ms. Each track is divided into tensectors in this hard-sectoring scheme.

In hard sectoring, the sectorboundaries are detected by means ofphysical holes punched through therecording surface of the disk. As thedisk rotates, these holes pass betweena light-emitting diode (LED) and aphotoelectric detector. Percomfloppy disks have ten sector holesevenly spaced around the hub hole ofthe disk, with a single additionalindex hole placed halfway betweentwo of the sector holes. This indexhole is used to identify one sector onthe disk as sector 0. Timing circuits inthe controller detect the shorterdistance between holes when theindex hole passes the photodetector.When the index hole is detected bythis method, the sector counter isreset.

Each sector occupies one tenth ofthe circumference of a track on thedisk and passes across the disk data-transfer head in 20 ms. Data is writ-ten to the disk at a rate of 1 byteevery 64 fis, theoretically giving roomfor up to 312 bytes per sector. It is notpossible to fully use these 312 bytes.The Percom format uses a maximumof 287 bytes for leader, header, usefuldata, and trailer, with the data lengthvariable from 1 to 256 bytes. Table 3details the format of data stored ineach sector.

Each track on the disk has ten sec-tors. The sectors are numbered indecimal from 000 to 349. In this three-digit numeral, the two high-orderdigits denote the track number in

48 May 1980 © BYTE Publications Inc

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which the sector is located. The low-order digit specifies the sector withinthe track. When we prefix this three-digit numeral with the number of thedisk drive, we obtain the externaldrive/track/sector (DTS) number, afour-digit quantity which is stored inbinary-coded-decimal (BCD) form in2 bytes.

For use in actual disk-addressingoperations, the external DTS number

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Field

Length in Contents

Name

Bytes

Leader

16 Binary zeros

Sync

1 Hexadecimal FB to indicate start of data

Current DTS

2 Drive/Track/Sector numbers of this sector

number

Backward link

2 DTS number of previous sector in file

Forward link

2 DTS number of next sector in file

Byte count

1 Length of data in this sector, in hexadecimal (00 means

hexadecimal 100)

Target address

2 Address of memory from which data was written

File type

1 Indicator of the nature of the data

Data

1 to 256 Data being stored

Check sum

2 2-byte cyclic redundancy check sum of all bytes after

sync byte

Trailer

2 DTS number of first sector of this file, or execution

address if this is last sector in this file

Table 3: Table

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second byte.

While the reformatting of the driveand track numbers from external tointernal format involves only a sim-ple decimal-to-binary conversion, thereformatting of the sector numberemploys a technique called alter-nating-sector addressing.

Why is alternating-sectoraddressing necessary? The sectors ofthe spinning disk pass under theread/write head consecutively, andthere is no time between sectors dur-ing which the disk-operating systemcan perform housekeeping functions.While KIMDOS is performing thehousekeeping routines for one sector,the next sector is already passing thehead. Since housekeeping and sectorreading cannot take place simulta-neously, reading the sectors in se-quential order would require thecomputer to wait for a full rotation ofthe disk to occur to read the sectorthat passed the head during house-keeping. Since every sector must betreated this way, only one sectorcould be read during each rotation ofthe disk if sectors were to be read se-quentially. To remedy this problem,the sequential sector numbers areconverted into alternating sectornumbers.

KIMDOS reads or writes alternatesectors on the disk; the disk mustrotate twice for all sectors on thetrack to be read or written. The orderof physical sectors is therefore not theorder of logical sectors. In the twocomplete rotations of the disk, thephysical sectors are read in thefollowing order: 0, 2, 4, 6, 8 (firstrotation); 1, 3, 5, 7, 9 (second rota-tion). Sectors are accessed alternatelyto allow time in between data-transfer operations for executinghousekeeping routines.

Each sector contains a sectorheader that holds information aboutthe sector and the file of which it is apart. The first two bytes of the sectorheader contain the DTS number ofthe current sector; this is used toassure proper head position whenreading. Each sector is linked via aforward pointer to the next sector andvia a backward pointer to theprevious sector. A forward pointerequal to 0 indicates the last sector in afile; a backward pointer equal to 0 in-dicates the first sector in a file.

The header also contains a data-length byte, a file-type byte, and theText continued on page 158

50 May 1980 © BYTE Publications Inc

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(3a) 1 millisecond

(3b) 2 milliseconds

(3c) 5 milliseconds

(3d) 10 milliseconds

Photo 1: A 5-second exposure with ASA 64 Ektachrome brings out significantcoronal detail twice per 25-exposure cycle.

Photo 2: A minimal length exposure shows the beginnings of some promi-nence detail and the inner corona. This exposure corresponds to the shortestnominal exposure time, 1 ms plus the minimum trigger-pulse width of 20 ms.The electromechanical system which is the Nikon MD-2 Motor Drive unfor-tunately has a minimum shutter-open time on the order of 20 ms. Thus the ex-posures nominally programmed at 1, 2, 5, and 10 ms were actually on theorder of 21, 22, 25, and 30 ms.

Text continued from page 6:

With this crucial timing step com-pleted, I turned my attention to re-fining the Pascal program shown aslisting 1 in the March 1980 BYTEeditorial. These refinements includedone conceptual change and sometrivial changes in the experiment'sdesign.

The conceptual change was that ofadding a single long exposure madeduring the "slack time" interval at theend of the eclipse sequence duringtotality. As noted earlier, the modelfor the eclipse photography sequenceused two manual inputs: one to starta sequence of diamond-ring ex-posures followed by automatic total-ity photography, and a secondmanual input to start the finaldiamond-ring sequence after a "slacktime" for synchronization. My con-ceptual change was to open the shut-ter of the camera during this slacktime, thus allowing one extremelylong exposure to take place whilewaiting for the second manual input.Thus by specifying a smaller numberof exposures during totality and alonger slack time, I would obtain thisone long exposure.

The relatively trivial changes beganwith the alteration of the table of ex-posure times to provide a total oftwenty-five different times instead often. In making this change I used theUCSD text editor to change the nameof the table in every occurrencethroughout the program. I alsochanged the initialization to provide a1, 2, 5 sequence of exposure times ineach decimal order of magnitude.(See photo 3's captions for the valuesresulting.)

Another relatively minor changewas to allow multiple tries at alloca-tion of the exposures, rather than fall-ing inexorably into a run of thephotography sequence. This changeproved quite useful in the field whereit provided a means of verifying that

52 May 1980 © BYTE Publications Inc

(3e) 20 milliseconds

(3f) 50 milliseconds

(3g) 0.1 second

(3h) 0.2 second

the computer had not died in the lastminutes prior to totality. The pro-gram also had to be modified to talkto a 40-character-wide field on theApple II video display instead of the80-character width available on theterminal I normally use. This changeamounted to condensation of thetexts displayed during the allocationprocedures. The final form of the pro-gram as used by the shores of LakeJipe on February 16, 1980 is shown inlisting 1.

The final equipment check prior toleaving was the verification that thedisplay on a 2-inch diagonal Sanyotelevision screen was adequate. Ajumper cord once used to interfacebetween a tape recorder and my oldhomebrew computer provided themeans for routing the output of theApple's auxiliary RF modulator to theSanyo television. The displaywavered a bit when running on theportable generator. It was a tinydisplay but adequately readable formy purposes.

After this crucial experiment, thefinal detail was to make redundantcopies of my eclipse application pro-gram's disk, as well as the UCSD Ap-ple Pascal system's disks Applel, Ap-ple2, and Apple3. Redundancy wasimportant. If I were to have a direc-tory crash due to dust or dirt while onthe other side of the equator 11,000miles from home, a second chancewould have been well worth it.

On Tuesday morning February 5,we hastened to Boston where the airtravel to Kenya began with a trip toNew York's Kennedy Airport. Theparty at this time consisted of myself,Tully Londoner, Norm Whyte, andLaurel Allen. Rick Lutman, the fifthmember of our party, would join usin Nairobi. In due course we boardedPan American's flight 190, an 18-hourinternational puddle jumper withstops at Roberts Field, Liberia, andLagos, Nigeria. The computer equip-

ment and telescope mount in additionto trunks and pack frames full ofclothes, sleeping bags, and tools con-stituted our luggage.

On reaching Nairobi at about 8 PMthat Wednesday, we met our guide,Iain Allan, and his associate VinceFayad. Iain does business as TropicalIce (Mountain Guides) Ltd, Post Of-fice Box 57341, Nairobi, Kenya.Making the connection with Iain wasthe only redeeming virtue of an other-wise hopelessly botched set of travelarrangements made by our US travelagents (who shall remain anony-mous). Iain was our guide to thewilds of Kenyan culture for the nexttwo weeks. His good humor andknowledge of local flora, fauna, andclimate are highly recommended toanyone traveling in East Africa forpurposes of game trekking ortechnical mountain climbing. Iainwrote the guidebook on Mt Kenyaand other climbs in Kenya. He alsofrequently guides technical climbingtrips on Tanzania's Kilimanjaro,when not tackling various otherchallenging rock climbs in places asdiverse as Nepal and Yosemite.

As in any trip of this kind, therewere some difficulties. The mostsignificant (and in retrospect, com-pletely avoidable) difficulty was theneed to post a 30,000 shilling bond onour equipment with Kenyan customson entry. We later had to recover ourcustoms bond on departure (minus anexorbitant 10% fee exacted by thelocal branch of a major US multina-tional bank). The fact that we had topost a bond at all was due to an un-

Photo 3: Black and white reproductions of the entireseries of different exposures taken with the aid of thefinal version of the Pascal control program for thecamera. Times are nominal shutter-open intervalsstored in a table in the program. Actual times reflecta fixed lower-limit overhead of approximately 20 ms.

(3i) 0.5 second

(3j) 1.0 second

(31) 5.0 seconds

(3m) 10.0 seconds

May 1980 © BYTE Publications Inc 53

fortunate mistake by one of our par-ty, a slipup which can possibly beavoided by readers in similar cir-cumstances.

When listing personal computerequipment being carried for such anexpedition, never ever list itsmonetary value or speak of its value.To satisfy US customs, all you need isa list of serial numbers of your per-sonal equipment carried abroad. Thislist can be used to advantage whenentering another country. But if yougive the customs officer at anothercountry the list of items and valuesyou prepared for your insuranceagent, it is like waving a red flag infront of a bull.

We had to post a customs bond onNorm's equipment using credit cardsto obtain nearly $4000 in cash, thenretrieve the cash bond at the end ofthe trip by pleading lack of time toKenyan customs officials in order to

get all the paperwork completed byour departure. We wasted two out ofsixteen days figuring out all the"catch-22"-style sophistries of thisproblem.

Kenya is a very British relic of aformer era, where dual languages ofSwahili and English dominate. Iainpointed out that it would have beenmuch more complicated in severalcountries in which he has traveledfor purposes of mountain climbing.In one Asian country he has visitedfor climbing, Iain points out, there isnot even a recognizable set of paper-work to be filled out. It was quite arelief to get back to a (relatively) saneUnited States at the end of the trip.

So much for the bureaucratic pro-blems of taking computers abroad toequatorial Africa. What about theengineering problems? We did asthorough a job of preparation as wecould, yet would the computers and

generator still play together when wereached our final encampment on theshores of Lake Jipe in Kenya's TsavoWest National Park?

We answered this question by anancient technique: crossing fingersand applying power. We arrived atLake Jipe 2 days before the eclipse,after a 6-hour trek over some incred-ible roads in Iain's Volkswagen buswith trailer in tow. The computerswere inside the bus with seven humanbodies and food packed with solidC02 in the famous Tropical Ice Box.All the rest of our gear was carried inthe trailer. The roads we traveledfrom Amboseli to Lake Jipe includedone 5-mile stretch of a semi-improvedlava flow, an unmarked dead endwhich looked like the main road oftwo alternatives, and othermiscellaneous "hazards" like herds ofelephants and troops of baboons.

The day before the eclipse, Norm

Photo 4: A view of the equipment set up at the Tsavo West National Park campsite on the shores of Lake Jipe. Norm was using a 500mm reflex lens with his camera; I was using my 1000 mm reflex lens. The two Nikon cameras were mounted on the equatorialtelescope mount carted to Africa along with the 110 VAC generator in Norm's homebrew plywood shipping trunk. The Apple Pascalsystem is shown sitting in the bottom of its carrying case on top of a trunk.

54 May 1980 © BYTE Publications lnc

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Listing 1: This is the final version of my Pascal Eclipse Control Program as used inKenya, February 16, 1980. Major changes from the previously published version in-clude filling in the details of real-time execution and modifying the exposure table toprovide twenty-five shots instead of ten. Also added was an interactive option toreenter the the exposures allocation phase so that different combinations of diamondring and totality exposures could be tried. Initialization now puts in a symmetrical risingand falling sequence of exposure times from 1 ms to 10,000 ms. All interactive textshave been adjusted so that they will fit the 40-character width of the Apple's built-invideo display.

NOTES ABOUT

THE

DESIGN

PROCESS

Step It High Level Description - begun November 22* 1979

This is a first cut at a program to simulate the eclipsephotography process? and define some of the necessary globaldata of the problem*

COMPLETED 11/24/79

* z

* p

* A

* a

* X

33

3J

J

33

33

333

333

}= extra slacK (one half of diamond ring total)}

Step 2! Fill in allocation details -

Achieve 3 complete allocation of the eclipse camera con-trol function 35 evidenced by calculation of a detailed timeline for the eclipse event given various conditions!Given .

n = number of totality exposuresn = number of diamond ring exposurest = totality time

s = slacK in allocated totality timeThen let us seek the following.**

# d2 = diamond ring time at 2nd contact

# d3 = diamond ring time at 3rd contact

= anticipation time (half first diamond ring)= reauired time for exposures during totality= allocated totality time for exposures= msrsin per frame in totalityTheorems t

d2*d3 derived from table of diamond ring frames

A derived from table of totality frames

z = <d2 + d3)/2

p = d2 / 2

a = t - s - z

x = < a - A) / n

PROCEDURES Detailed Here Are...ini tializenorm3lize

COMPLETED 12/16/79

Step 31 Fill in the simulated detsils...

Create a progrsm uhich uses the results of step 3 togo through 3 detailed time line of the experiment on P3Per(or terminal screen). Each event (shutter trsnsitionopen-->close or close—>oeen will be marked by a report ofits nature and time of execution relative to <start> signal

PROCEDURES Detailed Here Are...auai t_cue

diamond_ring_bursttotality

Step 41 Ad3pt to real time control -

Put in augmentations of the software to actually demon-strate operation with the Nikon F2A camera via a relayplugged into the Apple II Game Paddle SocketTHIS IS THE FINAL FQRM OF THE PROGRAM TO BE USED IN THEFIELD CONTROLLING THE EXPERIMENT...

Necessary step! determining a method of measuring timeintervals from the CF'U clock which is consistent with UCSDPascal. Possibly use assembly language subroutine.

PROGRAM eciiP5e_monitor_simulation»

CONST

min imum_pulse_width = 20 Cmi.l lisecondsl ioverhe3d_duration = 210 Cmilliseconds 3!

open_shutter_address = -16295 Csets ANO output to "1"}*close_.shu tter_address ~ -16296 (resets ANO output to "0"}!post_ring„delay - 500 Cmilliseconds}J

TYPE

seconds = INTEGER!

milliseconds = INTEGER!absolute_time =RECORD

Listing 1 continued on page 58

fired up the generator to supplypower. We then set up our respectiveApples. We naively thought that finalprogramming details could be ac-complished that day sitting in thetropical sun. But our preparationshad neglected to include a canopy orsun shade. Norm's Apple workedquite well in the heat, perhapsbecause he had rigged up a sort of sunshade using his towel, two cameratripods, and a large piece of gaily col-ored cloth.

My Apple, however, had been bak-ing in its carrying case all morningbefore I set it up. Its integrated cir-cuits were hot to touch even before Iturned it on. I turned it on and Pascalbooted as usual. I entered my eclipseprogram and proceded to check itout. But after one or two allocationruns, the operation of the programwas rather unusual and erratic. Asoften happens in such situations, Icycled the power switch in order toreboot the system's software. Withthis, the system simply refused tooperate in a normal fashion! Afterleaving the system off for about 2minutes, I was again able to get itstarted. But it crashed again morequickly.

My conclusion was that the directsunlight was baking my computer,giving it the electronic equivalent ofthe sunburn I was so carefullyavoiding for myself. It seems that Ap-ples do not work too well when tem-peratures are elevated to the pointwhere components are too hot totouch. I estimate that the surfacetemperature of the main board at thistime was in the range of 150° to180Fahrenheit (66° to 82° Celsius).Noting the excessive heat, I just turn-ed off the system and thought aboutstrategies for keeping it cool and outof sunlight until the eclipse happened.That evening after sunset and beforethe nightly parade of hippos began, Iverified that the computer was stillfunctional.

As it turns out, heat was not aproblem the next day, February 16,1980. The day of the eclipse brokewith a solid overcast, not anauspicious beginning. If first contactwere to have occurred at 8:30 in theText continued on page 66

56 May 1980 © BYTE Publications Inc

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Listing 1 continued;

units i seconds!

thousandths t milliseconds

end;

exposures = INTEGERSan._e;;posure_detail ■RECORD

duration * milliseconds*uai t„.af ter I millisecondsEND?string-pointer - tSTRINGJ

UAR

cr ash., ahead

an—in teser

x j ns i 3 tn awhich_r inst

: STRINGC128:;

: boolean;

integer;

integer;integer;

(second* third >;

ri n s_time

second-.con tact...rin=llhi.pd-.con tact.. ,.r instot., timetime-totali tyni3r3in_.timecurrent-timehalf-timeGuar ter ..timeslacK_.in_ totalitydu ititiiy

total_elapsed-timetotal-duration

maximumtotal-eclipser ins'-f ralliescurrent_shot

tuen ty_f ive_. shotstransient-shots

opening- "EUTILS*TEXT>5

absolute,absolute..absolute..J absolu te_.I absolute-I absolute! absoluteI absolute..! absolute.I absolute.t absolute.t absolute.! absolute.I absolute-exposures Jexposures;exposures iexposures;

t i m e J. time;.time;.time;.time;.time;.time;.time J

time;

time!

time;

time;

time;

timer

PACKED ARRAYLO..241 OF an..exposure_detai 1 iPACKED ARRAYCC.n OF an_e>:posure-detai 1 i

Miscellaneous routines used throughout the program }

new_pa=Je

Set-parameter

error _abor t

subtr 3ct_time

divide_Lime

add-time

print-time

PROCEDURE new_paae;VAR

stuff I STRINGC24:;

cle3r_screen '* CHAR;BEGIN

stuff := ' ';

clear-screen *.= CHR( 24 )»URITELNC clear_screen»stuff);URITELNC' ' >;URITELNC' ' );URITELNC s)END Cnew_pa3e3;

PROCEDURE Set. - parameterCVAR time t absolute_time)»WAR

3_strina : STRINGC128:;i : integer;

period : BOOLEAN;decirtial_count I INTEGER!factor* result : INTEGER;

PROCEDURE 3dd_a-diEiitC position I INTEGER );YAR

disit : integer;BEGIN

disit := ( ORDC s-5 trinsiC posit ion: )-0RDC '0' ) );IF period THENBEGIN

Listing 1 continued on page 60

Circle 30 on inquiry card.

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Lisfmg 1 continued:

decimal-count t= decimal-count + liIF decimal-count < 4 THENBEGIN

time.thousandths t= time,thousandths+ <<1000 * disit) PIV factor);factor != 10 * factorENDENDELSE Cbefore period]

time.units != (time.units * factor) + diait

end;

BEGIN Caet-parameter}

PAGE<OUTPUT )ttime.units 1= Oitime.thousandths i= Of

WHILE <<time.units=0> AND (time.thousandths=0>> DOBEGIN

factor != 10rdecimal-count 1= Ofperiod '.= FALSE!WRITELN(5)(REABLNf a-5trina)»

FOR i t= 1 TO LENGTH* 3_strina ) HOBEGIN

CASE a-StrinaCil OF

'0'f'l'»'2'i'3'r'4'»''3'»'A'»'7'i'B'»'9'tadd-3-diait( i )t

period := TRUEENDENDEND CUHILE5END Cset-parameter 3?

PROCEDURE error-abort?BEGIN

maximum (« 250»

total-eclipse != 200!

rin3-frames J= 25;

WRITELN<'Unrecoverable error in data/ )»

crash-ahead != FALSE

end;

PROCEDURE subtract...time( a»b J absolute-time. VAR c ! absolute-time);BEGIN

c.thousandths != a.thousandths - b.thousandths?sigma t- 0;

IF c.thousandths < 0 THENBEGIN

c.thousandths t= c.thousandths + 1000;siama I- -1

end;

c.units I- a.units - b.units + siama

end;

PROCEDURE divide„time<

VAR a J absolute-time;b I absolute-time;n ! INTEGER>!C a <-- b DIV n 3VAR

p.n ! INTEGERC163;BEGIN

a.thousandths 1= 0;a.units t« 0;o I= b.un its;

o := n * iooo;

a J= n + b.thousandths;

a 1= a DIV ni

p := o div iooo;

IF p < 32768 THEN

3.units != TRUNC< p )!p != h - ( 1000 * P )>IF p < 3276B THEN

3.thousandths (= TRUNC( p)

end;

PROCEDURE add_time< 3»b I absolu te_time; VAR c t 3bso.lute-i.ime >JBEGIN

siama 1= 3. thousandths + b. thousandths;

c. thousandths ',= siama MOD 1000;

c.units != a.units + b.units I <siama DIV 1000)

end;

PROCEDURE print-time(a I absolute-time);VAR

niooo.zioo : stringcn;

BEGIN

IF s.thousandths < 100 THEN zlOOO := '0' ELSE zlOOO != " iIF a. thousandths < 10 THEN zlOO != '0' ELSE zlOO t= "SIF LENGTH(s) > 25 THEN s != COPYCs.1>25>!URITELN(s.a.units.'.'.zlOOO.zl00.a.thousandths )

Listing 1 continued on page 62

60 May 1980 © BYTE Publications Inc

The Solution Store

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Listing 1 continued:

end;

«« opening "ENORMAL.TEXT»»

PROCEDURE normalize-timins,VAR

i : integer;

PROCEDURE 5um_up_rin3< r-insi INTEGER: VAR ring..total ! absolu te_tiM ) (WAR

index,i : INTEGERSthis-ring t absolute-time;

BEGIN

ring.,total .units ' = Ofring..total. thousandths t= post-ring-delay,FOR i t= 1 TO ring-frames DOBEGIN

this_rin3.units != Oi

this-ring.thousandths ! = transien t._5hotsCring3.wai t_af ter ;add_titrie( this_ring ,rin3-total, r ing.„total >Jthis..ring. thousandths i= transient-5hotsCringT*duration;add... timeC this_ring,ring-total , ring -total )ENDENDS

PROCEDURE sum._up_eclipse( VAR eclipse-total : ahsolute..time );VAR

this.shot \ absolute-time;index,i,J ! INTEGER;BEGIN

eclipse-total.units := 0J

eclipse-total.thousandths 1= overhead-duration;C this compensates for the minimum wait after one 1( frame started and ended during the slacK time period)FOR i != 1 TO total-eclipse DOBEGIN

this-shot.units : = OJindex != (i-1 ) MOD 25;

this ..shot, thousandths 1= twen ty.. five...shots! index 1 .wait..... after :add.... time< this—shotfeclipse-total jeclipse-total )»this-shot, thousandths : = twen ty..five., shot st indexD.duration5add...time< this-shot >eel ipse_total >eclipse..total )END

end;

PROCEDURE preliminary-allocation;BEGIN

5 := 'Allocation of Eclipse Times...'!neu-paSeJ

s 1 = 'Total time of eclipse = ';print_time(time-totality);

URITELN( ' ' )j

which_ring 1= second;

sum„up„ring< 0RD< which-ring ),second-contact., ring )J

5 != 'Second contact time = ';

print_time( second..con tact-ring );

which_ring 1= third;

sum-up..ring( 0RD< which_rins )»third-cont«ei_rintf )l

s i= 'Third contact time = ';

print_.tinie( third-con tact-ring );

add-Lime( second..con tact„rins»third-contact-ring,ring-time);

s t= 'Tot. diamond ring time = ';

print_time( ring...time );

divide-time( Quarter..timetsecond-contact-ring?2 )f

s i- 'Anticipation time = ';

print_time( Quarter..time >;

URITELN< ' ' );

5um„up...ecl ipseC tot.time ) 5

s t= 'Totality time = ';

print_time( tot-time );

5 *.= 'Margin at end totality = ';

print_time( siacK..in...totality )J

divide..time( half..time»ring..time>2 );s '.= 'Diantond ring slacK = ';

prin t_.time< half-time >;

sdd..time( tot-time t slacK_in_totali ty t to tal_durat ion )Sadd... time( total-duration Th3lf-ti me, total-duration >ls := 'Total time initially = ';print-time( total-duration >;

URITEl.N( ' ' >;

subtract_time< time-totality,total-duralion,margin-time );s != 'Margin for allocation = ';prin L_.time( mar din-time )END Cpreliminary-allocation 3; Listing 1 continued on page 64

62 May I960 © BYTE Publications Inc

Circle 34 on inquiry card.

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Listing 1 continued:

PROCEDURE marain-dispersal>VAR

marain_per_frame t absolute-time,i ! INTEGER.BEGIN

divide_time< marSin_per_frsme.marain-time. total._ecliPS,e );FOR i := 0 TO 24 DO

tuenty_five_shotsCi3.uait-after t=twenty_five_shotsCi_.uait-after +(1000 * mardin_per_fr3nie.units > +narsfin_.per-fr3me. thousandths,s 1= 'Hardin per tot. frame = ';print_time( ni3rsin_per_f r3me )END Cmarain-dispersal3»

PROCEDURE final_allocation!BEGIN

sum_up_eclipse(tot_time ).

s t= 'Adjusted total phase = ';

print_time< tot_time );

3dd_time( tot—time.slack_in_tatality.total-durstion )»add.. time< to ta.I -duration .half-time. total_dur3tion );s !~ 'Adjusted commitments = 'iprint_time< total-duration )i

3dd-time(tot_time.sl3cK_in_tot3lity.total-elapsed-time);3dd-time(tot3l_el3psed_time.rinS_time.total_el3Psed-time);s != 'Total elapsed time = ';

print_time( tot3l..el3Psed_time )J

URITELN<'

subtr3ct_.tiitie( time-totality, total-duration.marsin_time >;s '= 'Mar-in sfter 3llocation= ';print_time(mar_in_time )END Cfinal_alloc3tion3;

PROCEDURE alloc_exposures;BEGIN

rin__.f rsmes 1 =

<maximum - total-eclipse) DIU 2;

IF rins*-frames < 2 THEN error_abort;

siama != maximum - (total-eclipse + (2 * rinS-frames) );

tot3l_ecl ipse != tot3l..eclipse + 5idm3>

URITELN<'' )i

URITELN( ' Exposures mapf);

URITELNf'First diamond rins = ' »rina_frames );

l)RITELN<'Totality = ' > total-eclipse)l

WRITELN<'Second diamond rins = '.rins_fnames);

URITELN( '

URITELNC TOTAL

URITELN<'' >;

URITELNf ' ' >;

URITELNC'Press return to continue');

READLNt 5 )END Cal loc.exposures } J

BEGIN Cnormali-e_timina}

alloc„exposures i

preliminary-allocation;

marain_dispers3l»

fin3l_3llocatinn

END Cnorm3li-e.. timina};

PROCEDURE milli( time ! INTEGER);

external;

PROCEDURE ref-memoryf3ddress : INTEGER);

C This procedure uses the variant record technique toreference an address passed to it 35 a 16 bit sianedINTEGER. The flpple-II hardware will set or reset theannunciator outputs of the Game I/O connector if theappropriate 3ddresses sre simply referenced by a prosTsm.}

TYPE

ptr = tCHARJ

memory_3Ccess = ( pointen.number)

Cthis is 3 dummy statement reouired by the syntax ofPsseai variant records such as "memory" below. Thevariant record "trie!'." is not the most eleaant wayto reference an absolute hardware address, since itrequires an implementation-dependent assumption aboutV3ri3nt records, ie! that 3 1_ bit sianed two's complementINTEGER type maps bit for bit into the 16 bit positiveinteaer value1 of nr, atidr ess , stored in a Pascal pointerdats type.

3)

' >;

' .maximum );

Listing 1 continued on page 66

64 May 1980 © BYTE Publications Inc

Circle 36 on inquiry card.

Created t>y Dayner/HalUntf. Winter Park, FL

^

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Text continued from page 56:

morning as was the case in Montanalast year, we would have missed theeclipse. But by the time of first con-tact, about 10 AM, the clouds haddissipated somewhat in the hot sun,to the point where maybe 50 % of thetime the sun was obscured. What thisearly cloudiness did, however, waskeep my Apple from getting too hottoo soon.

As the eclipse progressed, the aircooled off. Whether this lack of in-solation due to the early phases of theeclipse affected the weather or not, itcertainly helped guarantee the perfor-mance of my Apple during the totalphase of the eclipse. At 11 AM when Iturned on the power to my computer,it was delightfully cool in comparisonwith the previous afternoon. Theweather had also improved con-siderably. We seemed by this time tobe in a beautiful bowl of clear bluesky with the nearest clouds perhaps 5to 10 miles away. This perfect eclipse-viewing weather lasted until wellafter the end of the event.

The Pascal system booted proper-ly, and I proceeded to set up the finalallocation I would use. Because Iwanted to take a few partial phaseshots manually, I had decided earlierthat morning to limit the shots oftotality to 200 exposures, with 120taken during actual totality and thebalance of 80 split equally betweenthe two diamond-ring events. A slacktime of 40 seconds was chosen toallow for the extra long exposuretoward the end of the eclipse. Just tokeep verifying the operation of thecomputer, I kept reentering theallocation phase of the program everyfew minutes.

Finally, at 11:21 AM, totality washeralded by a beautiful set of"shadow bands." After watchingthese last glimmers of direct sun, Iremoved the filter from my cameraand gave the first manual cue to myeclipse program. I then had four en-joyable minutes of direct viewing ofthe eclipse, its effects on the localanimal life, a glimpse of sunlight stillilluminating the upper part ofKilimanjaro, and the incredible col-orations of the distant clouds on the

Listing 1 continued:

memory =RECORD

case memory-access ofpointer t ( 3_pciinternumber t C a—numberENID

INTEGER)

vAR

3nybyte ! memory*anychar * CHAR*

BEGIN

anyhy te. 3-number ! =anyeh3r '= anybyte.

END f. ref ..memory 3»

3ddr-essSj-pointer t

exposure-detail);

PROCEDURE take_picture(photo2rsph !BEGIN

ref_memory( open-shutter_address )Jmilli(photograph.duration )»ref_memory(close_shutter_3ddres5 )Jnillit photograph♦wait-after )END C taKe_pieture3j

PROCEDURE initialize*VAR

running-index t INTEGER;BEGIN Unitialise)

5 t= ' ' f

ref_niemory(elose_shutter_3ddres5current-time,units 1= 0J

current-time.thousandths ! = 0.current_shot i- 0?twenty-five-shotsC03.dll rationtwenty-five-shotsC13.durationtwenty-five-shotsC23.durationtwenty_five_shotsC33.durationtwenty_five-ShotsC4D.durationtwenty-five_shot5C53.durationtwenty_five_5hotsC63.durationtwenty-five_shotsr_73.durationtwen ty_five_5hatsC83. durationtwenty_five_shotsC?3.durationtwenty_five_shotsC103.durationtwenty_five-shotsC113.durationtwenty_five_shotsC123.durationtuenty_five-shotsC133.dur3tiontwenty-five_shotsC143.durationtwenty_five_shotsC153.durationtwenty_five-shotsC163.durationtwenty_five_shotsC173.durationtwenty_five_shotsC183.durationtwenty-five_shotsC193.durationtwenty-five-shotsC203*durationtwenty_five_shotsC213.durationtwenty-five_shotsC 223.durationtwenty-five-shotsC233.durationtwenty_five-shotsC24 3.dur3tionFOR running_index != 0 TO 24 DOtwenty., five.. shotsCrunnin 3-indt

tr3nsient-shotsC03.dur3tiontransient-shotsC13.durationFOR runnina_inde>: != 0 TO I DOtr3nsient_shotsCrunnins'-inde

s != 'Restarting the prosfram' I

new_p33ei

WRITELN( 'Enter 0 to end* 1 to continue'WRITELN(' then <return> '>;

READLNt an-inteser>i

IF 3n_inte3er > 0 THENBEGIN

s != 'Preliminary dst3 initialization'!new_P33e»

s t= ' Enter number of exposures';

3et_P3r3nieter( dummy >;msximum != dummy.units?s t= 'Enter exposures in totality';REPEATBEGIN

Set..P3P3meter( dummy );total-.eclipse : = dummy.unitsEND

; =

1

+

iti i n ]

mum_pulse_

width

: =

9

+

min]

mum-pulse.

width

: =

5

+

min

mum-pulse.

.width

: =

10

+

miri:

mum_pulse.

width

: =

20

+

min:

mum_pulse_

W i d th

: =

50

+

iti in

mum_pulse.

.Width

; =

100

+

min

mum_pulse_

.width

; =

200

+

nun

mum_Pu lse.

.Width

! =

500

+

min

LUium-Pu lse.

.width

: =

1000

+

min

nium_pu X se.

.width

: =

2000

+

min

mum_pulse.

.Width

: =

5000

+

min

mum_pu1 be.

.Width

: =

10000

+

Hi in

mum_pulse.

.Width

: =

5000

+

min

mum_pulse.

.width

: =

2000

+

min

mum_PuJ.se.

.width

: =

1000

+

min

Lnium_pu lse.

.width

: =

500

+

min

Lnrun;_pu 1 se.

.width

; =

200

•f

min

Lmum_pulse

_width

! =

100

+

min

lmum-pulse.

-width

: =

50

+

min

Lmum_pulse

-width

! =

20

+

min

Lmum_pulse

-Width

: =

10

+

min

Lmum_pulse.

.width

: =

,J

+

min

Lmum_pulse.

-Width

: =

9

+

min imum_pu lse.

-width

: =

1

+

minimum_pulse.

-Width

dex3

. wai t_

after I- overhe«d-.duf

:= 5

+

min imum_F-ulse.

.width

;= 5

3

+

minittum_FUlse.

.width

x3.uait_3fter I

= over hesti

-dur si

Listing 1 continued on page 68

66 May 1980 © BYTE Publications Inc

Circle 37 on inquiry card.

6809 PROCESSING POWER!

only $199

The Percom SBC/9": A "10" By Any Measure

Available with either the new, powerful 6809 /xP or an optional 6800-software-compatible6802, here are 10 beautiful reasons why the Percom SBC/9™ is not just another runner-upMPU/Single-Board-Computer card.

O SS-50 bus direct, plug-in-compatible upgradeMPU. Requires no modification of the systembus, I/O or memory.

© Full-capability stand-alone single-board compu-ter. Accommodates a 6809 microprocessor or op-tional 6802 microprocessor without modifica-tion.

© On-card 1 K ROM monitor "auto-links" to optionalsecond 1 K PROM — if installed. Second PROMmay be used to easily extend or modify the prim-ary monitor command set.

O Eight-bit parallel port is multi-address extension ofsystem bus. Accommodates an exceptional vari-ety of peripheral devices ranging from game pad-dles and keyboards to memory managementmodules. Connector is optional.

© Serial port includes a full-range selectable bit rategenerator. Optional subminiature 'D' connectorprovides RS-232 compatibility.

© Extendable addressing via SS-50 bus baud linesto 1 Mbyte. Extendable addressing to 16 Mbytesor more through the parallel "super port."

© Includes 1 Kbyte of static RAM.

© All on-card I/O is fully decoded so that adjacentmemory space may be used.

© ROM circuit may be jumper-wired for single- ortriple-voltage 2716 EPROM.

© On-card power regulators simplify power supplydesign by minimizing regulation demands.

Plug the SBC/9™ into your SS-50system bus, and just that easilyyou've upgraded to the new super-fast super-powerful 6809 MPU withsuch programming amenities as 10addressing modes, 16-bit instruc-tions, auto-increment/auto-decre-ment and position-independentcode. Plus, you now have extendedaddressing capability, and opera-tion under control of PSYMON™,the most powerful and flexibile 1KROM 6809 operating system yetwritten.

Percom SYstem MONitor

PSYMON™ provides the usualROM monitor functions in 1 Kbyte. Itis easily extended and customizedbecause its unique "look-ahead"program structure first searches analternate command table. The ta-ble, if present, may be used to rede-fine or extend PSYMON's™ com-mand set.

And with PSYMON™, I/O is easilydirected to any peripheral device —even a disk system — through aDevice Control Block table located

in memory. This allows you to leavethe details of I/O software to theseparate I/O device drivers.

A PSYMON™ ROM is includedfree with the purchase of anSBC/9™. The Users Manual in-cludes a source listing.

The 1 Kbyte ROM monitor for theSBC/9™ 6802 option includes aprimary set of typical 6800-compatible monitor commands. Asfor PSYMON™, the commands areeasily extended or modified.

Products are available at Percom dealers nationwide. Call toll-free,1-800-527-1592, for the address of your nearest dealer, or toorder direct. Prices and specifications subject to change without notice.

™ trademark of Percom Data Company, Inc.

PERCOM DATA COMPANY. INC

211 N KIRBY GARLAND. TEXAS 75012

(211)272-3421

PERSOM

Listing 1 continued:

horizon. I used a second camera witha wide-angle lens to take severalhand-held pictures. Eventually themoment passed as Norm announcedthe coming of third contact aspredicted by his computer programrunning in conjunction with a Moun-tain Hardware real-time clock.Perhaps a bit too late, I gave my se-cond manual cue to my program, andI prepared to apply the lens cap toprotect the camera and optics.

The rest of the trip was, of course,anticlimactic. I had the satisfaction ofhaving had my program work asplanned, the good fortune ofavoiding a repeat of the thermal pro-blems of the day before the eclipse,and the knowledge that a significantimprovement in eclipse viewing canbe achieved using a computer system.We returned home the next Thurs-day, and by Friday noon I was able toview the images photographed by mysystem during those 4 minutes inTsavo the Saturday before. I don'tknow when I will next see a solareclipse, but I am sure that whateverthe state of the art of microcomputersat the time, I will be using one to im-prove my automation of photo-graphy of the 1980 eclipse.

Articles Policy

BYTE is continually seeking qualitymanuscripts written by individualswho are applying personal computersystems, designing such systems, orwho have knowledge which will proveuseful to our readers. For a more for-mal description of procedures andrequirements, potential authors shouldsend a large (9 by 12 inch, 30.5 by 22.8cm), self-addressed envelope, with 28cents US postage affixed, to BYTEAuthor's Guide, 70 Main St, Peter-borough NH 03458.

Articles which are accepted are pur-chased with a rate of up to $50 permagazine page, based on technicalquality and suitability for BYTE'sreadership. Each month, the authors ofthe two leading articles in the readerpoll (BYTE's Ongoing Monitor Box or"BOMB") are presented with bonuschecks of $100 and $50. Unsolicitedmaterials should be accompanied byfull name and address, as well as returnpostage.

UNTIL

< tot3.1.-ecli.pse > 0)

AND( lota 1... sc .1. :i, p s e < ri a ;■: .i. isuin ) ?>s != 'Enter lot,8,11 la duration <Set-parameter! lime..totality )"■5 !-■ 'Enter BlacK time (sec)' >get-parameter! slacK-in-total itsend;

crssh-ahead !- TRUEEND Ciniti3lize}>

PROCEDURE agait-cueiVAR

anychar ! PACKFD ARRAYCO. .0!] OF CHARBEGIN C3U3it

URITELNt'

URITELN1'

WRITELW '

PACKFl! ARRAY! 0cue?'

>;>:>;

WRITELW'#********************'!SWRITELNC' Awaiting manual, cue-' );URITF1.N('***#******#**********' )jUNITREAtK 2»anychar,]. ,0,0)END Csuai t... cue}»

P R OCEDURE d j a it, o n d. r i n S . b ur s t;WAR

i : integer;BEGIN Cdiamond-rins_hursl3

FDR i := 1 TO ring ..frames DOBEGIN

IF i;hi ch _r ins - second THEN

taKe-Picture< tr-ar.sient.-shotsL 0} )ELSE

taKe_pieture< trans lent-shotsC in )end;mil li( post r i nr' del sy )END Cdi3mond_ri n si-four s I ?;

PROCEDURE totality;WAR

exposure—count t INTEGERScyclic-choice ! INTEGER?BEGIN Ctotality}

URITELN!'Besin totality sequence'>Scyclic_choicp 1= Oi

FOR exposure—Count != 1 TO total-eclipse DOBEGIN

taKe-piclure(twenty_five-shotslcyelic-choieej >Jcyclic-choice != (cyclic-choice + 1! MOD 25end;

URITELNC'End totality seouence'!END Ctotality};

PROCEDURE summarize!BEGIN Csummarise3WRITELN< 'PressREADLN( s )END C summar i ze } J

'elurn to end pros

: 1. ipse-dancei

PROCEDURE perform..BEGIN

suait-eue;

diamond-ri nsl—four s t ">

totali ty»

ref -memory! open.. -;.hii I tec... address )i

3wai t—cue;

ref-memory ( close-shi Iter-., addr ess );

mil lit overhead..duration )J

diamond. .rinsUbltrst

end;

BEGIN {] eelipse...mon 1 toan- i n teSer- t = 1 00 ;WHILE an_inteHer >BEGIN

initialize;

TF an-inleste

BEGIN

normal

0 THEN

ze t i mi. ns;WRITELN! ' Is this an ecliREA0.LW •- )•

IF LENGTH's > < 1 THEN sIF i ( sill = 'a' ) OR ( sCiper form-eel ipse—dancsEND

end;

su [Timer izeFND . { eel ipse-mon i tor -sirau J. s Li an ?

)) THEM

68 May 1980 © BYTE Publications Inc

Your micro-computer deserves the bestin data base management

Get the most out of your micro-computer. Use an

advanced and progressive data managementsystem.. .one with many large-computerfeatures.. .one designed to meet your present andfuture needs.

HDBS is an extended hierarchical data basesystem offering

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2. file-level read/write protection

3. one-to-many set relationships

MDBS is a full network data base system offeredas an upgrade from HDBS.. .or it may be ideal asyour initial system. Unique and versatile, it addsthese features:

4. full network CODASYL-oriented data structures

5. variable length records

6. multiple levels of read/write protection

7. one-to-one, many-to-one, and many-to-manysets

8. non-redundancy of data, easy updating

9. occurences of a record type may own otheroccurrences of the same type

10. a single set may have multiple owner andmember record types

MDBS-DRS. As an add-on to MDBS, the DRSsystem offers extraordinary flexibility in data baserestructuring to meet new needs.

11. Item, record, and set types can be added,

deleted, or renamed in an existing data base aswell as other data base characteristics. You canredesign the data base after it is already on-line!

HDBS and MDBS Packages include:

• DDL data definition language analyzer/editor

• 260-page users manual

• DMS data management routines callable fromhost language

• Sample application program and DDL files

• Relocator to re-org all routines

• System specific manual for bringing up oursoftware

MANAGEMENT

Write or call for free copyof 54-page "primer" ondata base systems formicro-computers.

Both HDBS and MDBS Systems...

a. Run under CP/M (and similar derivatives) withMicrosoft BASICS, FORTRAN or COBOL; underNorth Star DOS with North Star BASIC; underTRSDOS or NEWDOS with TRS Disk BASIC andwith Apple DOS and Applesoft BASIC. Machinelanguage callable forms also available.

b. Up to 254 record-types definable in the data base;each record-type may contain up to 255 item-types; each item-type may be up to 9,999 bytes

in length.

c. Names of data items, records, sets, and files arewholly user definable.

d. Command to add, delete, update, search, andtraverse the data base.

e. Straightforward use of ISAM-like structures.

f. Records can be maintained in several sortedorders.

g. Written in machine language for maximumexecution efficiency and minimal memory usage.

h. Independent of types and sizes of disk drives.Support data base spread over several disk drives(max. 8); disks may be mini- or full-sized floppiesor hard disks.

i. Available in versions Z80 (requires approx. 18K),6502 (approx. 26K), and 8080 (approx. 22K).

Ordering and pricing information:

HDBS - Z80 $250.00

HDBS - 6502 325.00

HDBS - 8080 325.00

HDBS/MDSS Manual 35.00

HDBS - Upgrade to MDBS 550.00System Specific Manual (each) 5.00For machine languagecallable forms, add $75.00

We accept Visa and Master Charge.

When ordering, specify intendeduse with...

1. North Star DOS and BASIC

2. CP/M - Microsoft BASIC 4.XX

3. CP/M - Microsoft BASIC 5.XX

4 CP/M - Microsoft BASIC Compileror FORTRAN-80

MDBS - ZB0MDBS - 6502MDBS - 8080MDBS/HDBS ManualMDBS • DRS add-onMDBS - DRS Manual

$750.00

825.00

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100.00

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Add $2.50 handling fee fornon-cash order ($5.00 outside U.S.).Indiana residents add 4%.

5. CP/M - Microsoft COBOL-80

6. TRSDOS and TRS Disk BASIC

7. NEWDOS and TRS Disk BASIC

8. CP/M - machine language

callable form

9. Apple DOS and Applesoft BASIC10. (Other versions coming)

Name (please print)

Phone

Company

Address

City

State Zip

Master Charge #Vlsa#

Bank #

Expr. date (either card)

Finally, our software may cost a little more...but it's worth a lot more in quality and versatility.

MicroData HoseSystems

Box 248, Lafayette, Indiana

SE <A> I

.inc. ©

iana 47902 / 317-742-7388

Circle 38 on inquiry card.

BYTE May 1980 69

Critique of Technique

This use of computer automa-tion in photographing a solareclipse provided a valuable im-provement over manual methods.Computer automation allowed meto plan an exposure sequencewhich would be executed withoutrelatively error-prone manualoperations. This goal was achievedin the experiment described here.But by building on experience, onecan always improve the tech-niques.

A relatively simple improve-ment would be to devote someautomation to the partial phases ofthe eclipse. This would be ac-complished by adding a loop totake photographs, for example,every five minutes, listening forthe manual cue of imminent total-ity between partial phase shots.This would also assume coolenough temperatures for reliableoperation over a 90-minute timespan. I left this feature out becauseI had no idea of the proper ex-posure time to use and was toobusy getting the main goal ac-complished.

The problem of determining themechanical overhead of the NikonMotor Drive in the "bulb" positionneeds further attention. The short-est exposures in the 1980 eclipsewere dictated by a fixed overheadtime needed to ensure reliable trig-gering of the motor drive. If thistime is too long, given the film us-ed, then two options remain: usinga slower film, or applying a filterto the lens during totality. Thediamond-ring exposure times weremuch too long for a goodphotographic result. This problemwould go away if a slower film orfilters were applied. Since anequatorial telescope mount wastracking the sun during the eclipse,use of slower film would give ashorter effective minimum ex-posure time without sacrificingresolution with the long shots.

Two problems with my pro-cedures during the 1980 eclipse willnot go away given improvements

in computer systems techniques.The first problem is that of inade-quate timing cues. While it wouldbe possible to use a real-time clockto coordinate with universal time,such an open-loop operationwould not necessarily guaranteebetter timing of the start of the se-quences of totality photographsdue to imprecision in our know-ledge of latitude and longitude at aremote site.

The second difficult problem isforgetting to verify focusing of thecamera during the automatic se-quence. In this eclipse, I was lucky,because I did not jar the camerawhile removing the filter. But,quite frankly, I forgot to even lookthrough the viewfinder while theautomatic programming sequencewas in operation. Had I twisted thebarrel of the lens while removingthe filter I could have had a realdisaster of unfocused results.

And of course, the next time I goto the tropics with a computer, asun shade of some sort will accom-pany me.

High-Level Conference

A key part of the success of thisapplication of a personal computerto eclipse photography was the useof a high-level language system fornearly all of the programming.Listing 1 shows the final version ofthe eclipse camera-control pro-gram with an additional month'sdevelopment from the state shownin listing 1 of the March 1980editorial. This very successful useof Pascal in a relatively sophisti-cated engineering application helpsemphasize the importance of thehigh-level-language design ap-proach.

The importance of high-levellanguages in design extends farbeyond any particular application.To help provide our professionallyoriented readers with an intensiveexposure to the design philosophyof modern software tools for smallcomputers, we have created a

seminar on the subject. Theseminar is organized in conjunc-tion with the McGraw-Hill Con-ferences and Seminars group. Itwill be held at the McGraw-Hillbuilding in New York City, June 16and 17, 1980. The sessions of "TheBYTE Conference on Languagesand Tools for Microcomputing"will include six important talks onseveral essential high-level-lan-guage systems concepts for smallcomputers.

Dr Fred Martin of IntermetricsIncorporated will talk about thehigh-level language-oriented soft-ware tools developed for the real-time systems programming of theNASA Space Shuttle flight com-puters. Dr Peter Grogono, authorof Programming in Pascal, will pre-sent the philosophy of Pascal, thepredominant block-structured,strongly typed language of con-temporary microcomputer usage.Dr Ken Bowles, the driving forcebehind UCSD Pascal, will providea fascinating talk entitled "AfterPascal, What?" which concernsproposed microcomputer im-plementations of the US DefenseDepartment's Ada language. JohnMorse of Digital Equipment Cor-poration will set Bell Laboratories'C language into a microcomputercontext, describing its value as asystems and applications programimplementation language. DrCharles Moore of Forth Incor-porated will describe the character-istics of Forth as a programmingtool appropriate for small com-puters. Dr Henry Baker of theUniversity of Rochester will com-plete this suite of language-orient-ed tools for microcomputers bypresenting information on LISPand its applications. This 2-day in-tensive conference will end with apanel session in which all thespeakers will participate.

For further information, contactThe McGraw-Hill Conference andExposition Center, 1221 Avenue ofthe Americas, Rm 3677, New YorkNY 10020, or see the advertisementin this issue. ■

70 May 1980 © BYTE Publications Inc

Now...

You, the small systems user can enjoythe advantages of Hl-performancelow c<^ computer graphics

Digital Plotters

Digitizers

For complete information contactHouston Instrument, One HoustonSquare, Austin, Texas 78753.(512)837-2820. For rush literature re-quests persons outside Texas calltoll free 1-800-531-5205. In Europecontact Houston Instrument,Rochesterlaan 6, 8240 GistelBelgium. Phone 059/27 74 45.

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Resolution and repeatability of0.005 in. (0.1 mm)Origin is completely relocatableRS232C and 8 bit parallel inter-face selectable at the connectorAccuracies of ±0.015 In. (0.4 mm)Optional LC display shows actualvalues being InpuiDigitizing surl 11"

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y

,i....lh» n.mm

Interface a Floppy-Disk Driveto an 8080A-Based Computer

John Hoeppner

Shugart Associates

415 Oakmead Pky

Sunnyvale CA 94086

The audio cassette has been usedby most of us for off-line storage ofprograms and data. It has two advan-tages: it is inexpensive, and it is easyto implement because of the widevariety of cassette interfaces avail-able.

However, I grew tired of waitingfor the BASIC interpreter and all mydata to be loaded every time Ipowered up my system. Even then, Isometimes had to load and reload thedata until the interpreter and my pro-grams were transferred correctly. Idecided to try an alternative.

On one hand, the Shugart mini-floppy 5-inch disk drive, which costsabout $350, was a little more expen-sive than my cassette recorder; but,on the other hand, the 5-inch floppydisk it uses costs about the same as aquality cassette tape — around $4.And, despite a higher initial invest-ment, the floppy disk is more reliable,and it can transfer programs and dataas much as thirty times faster than theaudio cassette. It seemed the moreprograms that were developed, themore worthwhile the additional in-vestment would be. Also, with arecently introduced integrated circuitfrom Western Digital, the FD1771floppy-disk formatter/controller, Icould design a controller myself thatcould be interfaced to my

Minifloppy is a registeredtrademark of Shugart Associatesused to describe their 5-inchfloppy-disk drives.

8080A-based microcomputer system.This article describes the hardwaredeveloped to connect a Shugartfloppy-disk drive to an 8080A-basedsystem using the Western DigitalFD1771 chip, as well as the softwareroutine necessary to drive theFD1771.

The FD1771 diskformatter/controllerdevice is compatible withthe IBM 3740 format.

Hardware Characteristics

The 8080A-based microcomputerwas one that I designed. However,the components I used are thosefound on most 8080A single-boardcomputers: an 8080A microproces-sor, an 8224 two-phase clock, an 8228system controller and bus driver, andan 8255 programmable peripheral in-terface. (See figure 1.) For temporarydata storage, I used 2 K bytes of pro-grammable memory, and for mybootstrap loader, I used a 256-byteprogrammable read-only memory.The microcomputer interfaces to theFD1771 through the programmableperipheral interface (PPI), which canbe programmed as three input/output(I/O) ports of eight lines each.

The FD1771 disk controller is com-patible with the IBM 3740-type, soft-sectored format, but it can be pro-grammed for other formats. It con-

tains five registers: data, command,sector, track, and status. Theseregisters hold the data and commandstransferred from the 8080A pro-cessor. The FD1771 has a cyclicredundancy check (CRC) generatorfor performing a validity check ondata transfers. It is also equippedwith an internal data separator forseparating clock and data bits fromthe disk into two separate streams. Ichose not to use the internal dataseparator for the following reason.

Each bit of data on the disk isstored during a time interval called abit cell. The bit cell is the space be-tween two of the clock pulses that arerecorded on the disk; the beginning ofthe bit cell is defined by the clockpulse. If the bit is to be recorded as a1, a pulse is written in the center ofthe bit cell. If the bit is to be recordedas a 0, no pulse is written in the cell.

The bit pulse must be written onthe disk inside certain boundaries.When the pulse is read by the diskdrive, the pulse is presented to thecontroller within a certain time framecalled the data window. The lengthof the bit cell is 8 /ts. When the clockpulse is detected by the controller, atimer is activated. This timer counts 2(is; after 2 /is have elapsed, the datawindow is deemed to be "open." Thedata window is open during 4 /is, andthe bit pulse is expected to be foundduring the data-window interval.After the interval of the data windowin over, the controller looks foranother clock pulse to begin the nextbit cell.

72 May 1980 © BYTE Publicalions Inc

a. INTE5TEC DATA SYSIEMS SUPEJBRAIN

7 ' 7 ' 7 '■ 7 ' 7T ' 7 7 7

The Honor Graduate

There's been a lot of talk latelyabout intelligent terminals withsmall systems capability. And, it'salways the same. The systemswhich make the grade in perfor-mance usually flunk the test inprice. At least that was the caseuntil the SuperBrain graduated withthe highest PPR (Price/Perfor-mance Ratio) in the history of theindustry.

For less than $3,000*, SuperBrainusers get exceptional performancefor just a fraction of what they'dexpect to pay. Standard features in-clude: two dual-density mini-flop-pies with 320K bytes of disk storage,up to 64K of RAM to handle eventhe most sophisticated programs,a CP/M Disk Operating Systemwith a high-powered text editor, as-

*Quantity one. Dealer inquiries invited.

Circle 41 on inquiry card.

sembler and debugger. And, withSuperBrain's S-100 bus adapter, youcan even add a 10 megabyte disk!

More than an intelligent terminal,the SuperBrain outperforms manyother systems costing three to fivetimes as much. Endowed with ahefty amount of available software(BASIC, FORTRAN, COBOL), theSuperBrain is ready to take on yourtoughest assignment. You name it!General Ledger, Accounts Receiv-able, Payroll, Inventory or Word Pro-cessing . . . the SuperBrain handlesall of them with ease.

Your operators will praise theSuperBrain's good looks. A fullASCII keyboard with a numeric key-pad and function keys. A non-glare,dynamically focused, twelve inchscreen. All in an attractive desktopunit weighing less than a standardSee us at NCC booth 2240

office typewriter. Sophisticatedusers will acclaim SuperBrain's twinZ-80 processors which transfer datato the screen at 38 kilobaud! Inter-facing a printer or modem is noproblem using SuperBrain's RS-232C communications port. But bestof all, you won't need a PhD in com-puter repair to maintain the Super-Brain. Its single board design makesservicing a snap!

So don't be fooled by all the fresh-man students in the small systemsbusiness. Insist on this year's honorgraduate . . . the SuperBrain.

3

sinte3tecCdatae systems,

2300 Broad River Road, Columbia, SC 29210(803) 798-9100 TWX: 810-666-2115

BYTE May 1980 73

r

~l

ADDRESSDECODE

PAO

CHIPSELECT

DATAPORTC

8255PROGRAMMABLEPERIPHERALINTERFACE

1

DATASEPARATOR

READDATA

TO

FLOPPY

DISK

DRIVES

L

READ-ONLYMEMORY

Figure 1: Block diagram of 8080A-based computer and interface to Shugart SA400 floppy-disk drive. The Western Digital FD1771disk-controller circuit is illustrated here as the area within the dotted lines.

The problem with the FD1771 in-ternal data separator arises from thecounting after the clock pulse to findthe beginning of the data window.The counter in the FD1771 is syn-chronous with the system clockpulses (at 1 MHz) that are fed into theFD1771. However, the pulses fromthe disk arrive at the controller asyn-chronously; the variation in the ar-rival intervals of the pulses is causedby a host of factors. Therefore, thedata window as determined by theFD1771 can occupy varying positionswithin the bit cell. The position mayvary by as much as 1 /is (ie: 1 clockcycle) within the 8 /is bit-cell interval.

In worst-case data patterns, thisproblem may lead to errors and lossof data. Therefore, I provided a dataseparator of my own design to re-place the internal data separator ofthe FD1771. My data separator wasbuilt using a number of discrete logicgates of the 7400 family, as presentedin figure 2.

The 5-inch floppy-disk drive I usedwas a Shugart SA400 minifloppydrive. It is organized to store data inthirty-five independent tracks. Eachtrack contains 3125 unformattedbytes for a total unformatted capacityof 109.4 K bytes per disk. The for-

matting method I used results in anactual capacity of 71.68 K bytes perdisk. The track-to-track access timeof the data-transfer (ie: read/write)head is 40 ms. Once the read/writehead is positioned above the correcttrack, another 10 ms of settling timemust be allowed before a read orwrite operation can be performed.The basic data-transfer rate of thedrive is 125 K bits per second, whichtranslates to 15.6 K bytes per second.This compares to the audio cassetterecorder's transfer rate of about 500bytes per second.

Connecting the 8255 PPI

The 8255 programmable peripheralinterface provides a universal meansof interfacing peripheral devices tothe 8080 microprocessor. It interfacesto the data bus through the 8228system controller and bus driver.Three address lines (A0, Al, andA15) of the 8080A are connected tothe 8255. Line A15 is connected to thechip select ( CS ) line of the 8255, giv-ing the PPI a memory address ofhexadecimal 8000. Lines A0 and Aldirectly access registers in the 8255.This method of I/O addressing iscalled memory mapping, because itmakes certain memory addresses act

as registers for communication be-tween the computer and theperipheral device: it was necessarybecause the conventional I/O instruc-tions were too slow.

The FD1771 interfaces to the pro-cessor through eight data lines (PB0thru PB7) and seven control lines(PA1, PC0, PCI, PC2, PC3, PC6,and PC7), as shown in figure 2 (page78). Ports A and B of the PPI, eachproviding eight lines for transfer ofdata, interface with the data lines ofthe FD1771. Three lines of port A alsoconnect directly to the disk drive.Port C of the PPI handles the FD1771control lines. The eighth control lineof the FD1771 is not used, so it is tiedto ground.

Six of the outputs of the PPI (PAOthru PA3, PC2, and PC3) are logical-ly inverted. Because the outputs of allports on the 8255 go low when anyport is commanded to change direc-tion (from input to output, or viceversa), this inversion is necessary toprevent false signals from going to theFD1771, deselecting the drive andturning off the motor.

Due to total system-timing con-straints, disk read and write routinesmust be performed within 56 /is.Text continued on page 80

74 May 1980 © BYTE Publications Inc

Circle 42 on inquiry card.

Quiet Designs forecasts a new anbrighter future for your flexible disks..,...introducing Jlip Sort™

• Library Concept

Easy filing, easy retrieval.

• Index Dividers

Adjustable tabs can be set to desired positions.

• Durability

Each unit is molded from a highly-durable,transparent, smoke-colored acrylic.

Quiet Designs

Quiet Designs Bay Area473 Macara #706Sunnyvale, Ca. 94086(408) 739-5215Contact Debbie Sherrick

Quiet Designs Inc.

1330 W. Robinhood Dr., Suite F

Stockton, Ca. 95207

(209) 957-8631

Contact Garry Potten

• Storage Capacity

Each unit has a storage capacity of 50-60disks. The unique lid design provides for easyaccess and also doubles as a carrying handle.

• Sizes

Both Mini Disk (5%") andLarge Disk (8") sizes available.

See us at NCC booth 26.

Quiet Designs Ltd.2nd floor, 1198 W. PenderVancouver, B.C. V6E 2R9(604)681-7532Contact Ken Magoski

Quiet Designs Calgary Ltd.101 Tenth Ave. South eastCalgary, Alberta T2G 0V8(403) 237-6187Contact Roy Moore

"Percom Sells MoreMicrocomputer Disk

Systems Than AnyOther PeripheralsManufacturer.

I'd like toshow you

VK***

>n mim

"Percom has been manufacturing mini-disk storage systems for microcomputers since 1977when we introduced the 35-track, single-drive LFD-400™. Now we produce 1-, 2- and 3-drivesystems in 40- and 77-track versions, a multi-density MEGABASE™ system and a hostof accessories and software.

"Volume not only means experience in critical production and testing operations, it alsomeans we can offer superior design features, extra testing and qualified backup support atvery competitive prices."I know of no other microcomputer disk system manufacturer who even begins to offer

the broad spectrum of disk equipment and programs available from Percom.""So before you buy a mini-disk system for your 6800, 6809 or TRS-80* computer, take agood look at what the people at Percom have to offer." Harold Mauch

President, Percom Data Company

Percom disk systems start at only $399.00. Disk systems and otherquality Percom products are available at computer dealers nationwide.Call toll-free, 1-800-527-1592, for the locations of dealers in yourarea, or to order direct.

PEFOCM

PERCOM DATA COMPANY. INC.

211 N KIRBY GARLAND. TEXAS 75042

C2141 272-3421

PRICES AND SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE.

TM trademark of Percom Data Company, Inc. 'trademarK of Tandy Radio Shack Corporation which has no relationship to Percom Data Company.

76 BYTE May 1980

'From an efficient lK-byte control system DOSto high level languages such as FORTRANand Pascal, no othermicrocomputer disksystems manufacturerprovides the range andquality of developmentand application programsavailable from Percom."

"Connie is running a 'cats eye' test on a mini-diskdrive to check radial track alignment. Drive motor-speed timing and sensor alignment tests have alreadybeen performed. Disk formatting and formatverification tests are next. Thesemeasurements are part of the100% testing every singleunit receives."

"Whether you call about ashipping date or ask a toughtechnical question, you get acompetent courteous answer.Outstanding customer service ,is a hallmark of Percom."

"Richard's making finalchanges to a disk controllerwhich will allow Percom drives tobe used with yet another computer.We're constantly developing andintroducing new products that extendand enhance rfi'm the value of

Percomsystems."

l^v*C

"Slipping a circuit board through the eye of a needle would

be easier than slipping a cold solder joint past Beverly. These

are four-drive LFD-400/800 disk system controllers

she's inspecting."

Circle 43 on inquiry card.

BYTE May 1980 77

Number

Type

+ 5 V

GND -

-5V +12V

IC1

8080A

20

2

11 28

IC2

8228

28

14

IC3

8255

26

7

IC4

FD1771

21

20

1 40

IC5

8224

16

8

9

IC6

7404

14

7

IC7

7404

14

7

IC8

9602

16

8

IC9

9602

16

8

IC10

7414

14

7

IC11

7414

14

7

IC12

7438

14

7

IC13

7438

14

7

IC14

7474

14

7

IC15

7474

14

7

IC16

9602

16

8

IC17

7400

14

7

IC18

7400

14

7

IC19

7404

14

7

r

SYSTEMCOMPUTER

31

^rr

r

02

RDY

RES

SYNC

AO

p2 HDY RST S

Figure 2: Disk-controller board. The circuit to the left of the dotted line is part of the computer being interfaced; the part to the right isthe interface to the floppy-disk drive. The area in the dotted box is a data separator made from 7400-series TTL devices. It separatesthe clock bits from the data bits as they come from the disk drive.

78 May 1980 © BYTE Publications lnc

Circle 44 on inquiry card.

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Text continued from page 74:Therefore, it was necessary duringthe design process to shorten the timefor checking the status of the drive.To allow fast status checking, bit 7,the most significant bit, of port C istied to the FD1771's data-request line(DRQ). The value of the DRQ isbrought into the accumulator by per-forming a memory-access instruction.It is then possible to perform aninclusive-OR of the accumulator withitself (ORA A), which results in the

sign bit being set to 1 if there is a datarequest (ie: if DRQ is high). Based onthe status of the sign bit, control canbranch to the appropriate routine.This arrangement eliminates the needto perform a separate check on thestatus bits using one of the logical in-structions, thereby saving a signifi-cant amount of time.

Interfacing to the SA400

The SA400 drive has connectionsfor twelve transistor-transistor logic

A1 AO Register Affected During

Read (RE = 0, WE=1)

0 0 Status Register

0 1 Track Register

1 0 Sector Register1 1 Data Register

Register_Affected DuringWrite (RE=1, WE = 0)Command RegisterTrack RegisterSector RegisterData Register

Table 1: Access to registers within the Western Digital FD1771 disk formatter/con-troller device. The FD1771 has five internal registers: command, data, sector, status,and track. A given register is read or written by placing the appropriate values onlines Al and AO and pulling down either the READ-ENABLE (RE) line for a readoperation, or the WRITE-ENABLE ( WE) line for a write operation. The sectorand track registers specify the sector and track when these parameters are needed bya given command byte. The command register, when filled, causes one of elevenhigh-level instructions to be executed (see table 2). Data passes between the com-puter and the disk drive through the data register. After a command has been exe-cuted by the FD1771, the status register must be read before another command canbe executed.

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(TTL) compatible signal lines. Sevenof them connect directly to theFD1771 lines through type-7414Schmitt-trigger inverters used as linedrivers and 7438 open-collectorNAND buffers used as line receivers.The WRITE-DATA line transmitsdigitized serial data to be written onthe floppy disk. The WRITE-GATEsignal, when activated, causes thedata to be written on the disk. The

WRITE-PROTECT line, when ac-tive in a low state, indicates that awrite-protected disk has been insertedin the drive. The STEP line, whenpulsed, causes the read/write head tomove radially a distance of one track.The DIRECTION-SELECT linedefines the direction that theread/write head moves when the

STEP line is pulsed. The

TRACK-00 line, when low, in-dicates when the read/write head ispositioned over the outermost track,track 0. The INDEX line transmitsthe pulse that occurs once for everyrevolution of the floppy disk to in-dicate the beginning of a track. (Thepulse comes when the index holepasses the photodetector.)

Three drive-select lines, whichassign the logical drive address, areconnected to port A of the 8255through 7414 and 7438 circuits usedas line drivers and receivers. A

MOTOR-ON line, also tied to the8255, controls the spindle-drivemotor. The READ-DATA line istied to the monostable multivibrator(commonly known as a one-shot)that shortens the pulse width from thedrive to 300 ns before sending it to thedata separator.

The FD1771 has nine other controllines, which control head positioningand data transfers, but which do notinterface directly to the disk drive.Four of the lines to the FD1771 arenot used. Lines TEST , DINT ,

WF and 3PM are therefore tied to+ 5 V through a 10 k-ohm resistor.

Of the remaining five control linesfor the FD1771, the SEPARATED-CLOCK and SEPARATED-DATAlines transmit the clock and data bitsfrom the data separator. (Clockpulses are used in frequency mod-ulated (FM) encoding to signal thebeginning of a bit cell.)

The READY line, which signalsthat the drive is ready for a read orwrite operation, must be active forthe FD1771 to perform any function.

Text continued on page 84

80 May 1980 © BYTE Publications Inc

Circle 124 on inquiry card.

Circle 45 on inquiry card.

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TYPE

COMMAND

Restore

Seek

Step

Step In

Step Out

Read Command 1

Write Command 1

Read Address 1

Read Track 1

Write Track 1

Force Interrupt 1

6000

11

00

11

11

(a)

4

0

1

u

u

u

m

m

0

0

1

1

BITS

3

h

h

h

h

h

b

b

0

0

0

2

VVVVVEE111

0a,000

BIT VALUES FOR TYPE 1

h = Head Load flag (Bit 3)h = 1, Load head at beginningh = 0, Do not load head at beginning

V = Verify flag (Bit 2)

V = 1, Verify on last track

V = 0, No verify

r,r0 = Stepping motor rate (Bits 1 thru 0)r,r0 = 11 gives 40 ms step time

u = Update flag (Bit 4)u = 1, Update Track registeru = 0, No update

(b)

BIT VALUES FOR TYPE II

m = Multiple Record flag (Bit 4)

m = 0, Single record

m = 1. Multiple recordsb = Block length flag (Bit 3)

b = 1, IBM format (128 to 1024 bytes)

b = 0, Non-IBM format (16 to 4096 bytes)a^p = Data Address Mark (Bits 1 thru 0)

a,ao = 00, FB(Data Mark)

a,a0 = 01, FA (User defined)

a,a„ = 10, F9 (User defined)a,a0=11, F8 (Deleted Data Mark)

(c)

BIT VALUES FOR TYPE III

s = Synchronize flag (Bit 0)

s =0, Synchronize to Address Mark

s = 1, Do not synchronize to Address Mark

(d)

BIT VALUES FOR TYPE IV

l0 thru l3 = Interrupt Condition flags (Bits 3 thru 0)

l0= 1, Not Ready to Ready transition

I, = 1, Ready to Not Ready transition

l2 = 1, Index pulse

l3=1, Immediate interruptE = Enable HLD and 10 ms Delay

E = 1, Enable HLD, HLTand 10 ms delay

E = 0, Head is assumed engaged and there is no 10 ms delay.

(e)

Table 2: The high-level instructions of the FD 1771 disk for-matter/controller device. When one of the instructions asdefined by table 2a is loaded into the command register of theFD1771, the FD1771 executes one or a series of actions. Bitsrepresented by a letter within a command are defined in thebit value tables for that type instruction, tables 2b thru 2e.

82 May 1980 © BYTE Publicalions Inc

Circle 46 on inquiry card.

Text continued from page 80:

Since the Shugart SA400 floppy-diskdrive has no "ready" signal, thedrive's index signal is used to deter-mine a ready condition.

The disk drive transmits the indexpulse only when the drive door isclosed, the disk is inserted, and thespindle motor is turning. Because theindex pulse is transmitted once foreach rotation of the disk, the speed ofrotation may be determined bymeasuring the interval betweenpulses. When the drive spindle hasreached final speed, the index pulse istransmitted at intervals of 200 ms.

I used the index pulse to trigger amonostable multivibrator, whichgenerates a one-shot pulse with alength slightly greater than 200 ms.When the drive is up to speed, theone-shot is continuously activated,since the index pulse retriggers it at200 ms intervals. This one-shot pulseis connected to the ready line on theFD1771, and the derived "ready"signal remains true as long as thedrive is ready.

The HEAD-LOAD and HEAD-LOAD-TIME lines are related in func-

tion. When the FD1771 issues a com-mand to the drive, the drive mayhave to first load the head. The head-load time for a Shugart SA400 driveis 75 ms. Since the FD1771 is designedfor use with drives having a shorterhead-load time, a time-out signal toindicate that the head is loaded mustbe generated externally. To insurethat the head is loaded, the HEAD-LOAD signal from the FD1771 is tiedto a monostable multivibrator havinga pulse duration of 75 ms. The outputis fed back to the FD1771 as itsHEAD-LOAD-TIME input to forcethe FD1771 to wait for 75 ms beforesending a read or write command tothe drive.

The FD1771 controls the floppy-disk drive with one of several 8-bitcommand words; these commandwords are high-level in the sense thateach initiates a series of operationsthat define the function requested.Generally, each command requiressome type of parameter. So, beforethe 8080A microprocessor sends acommand, it must first load thenecessary parameter in the form of an8-bit byte into the appropriate

register of the FD1771, whether thedestination is the data, sector, ortrack register.

To place the necessary data in aregister, address lines A0 and Al areset according to the data in table 1,the READ-ENABLE (RE) line is heldhigh and the WRITE-ENABLE(WE) line is pulled low. To imple-ment a command, lines A0 and Almust address the command register.An' 8-bit byte representing the ap-propriate command is placed on thedata lines of the FD1771 (via the Bport of the 8255) and is sent to thecommand register as the WRITE-ENABLE line is toggled from high tolow.

FD1771 Commands

The FD1771 recognizes elevenhigh-level commands; these are il-lustrated in table 2 with their binaryrepresentations. They can be dividedinto four types. Type I commands areused to move the drive's read/writehead. Type II commands are read-and write-sector commands. Type IIIcommands are read-address, read-track and write-track or formatting

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84 May 1980 © BYTE Publications Inc

Circle 48 on inquiry card.

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commands. Type IV includes a classof command that raises the FD1771interrupt line on a given condition.

The restore command causes theaddressed drive to move the head to(or seek) track 0. When the seek com-mand is executed, the addressed diskdrive positions the read/write headover the track specified by the 8080A.The step command causes the drive tostep the head one track in the direc-tion previously selected. The step-incommand causes the head to step onetrack toward track 35, the innermosttrack. With the step-out command,the head steps one track toward track0.

A read command transfers a fullsector of data, 1 byte at a time, fromthe disk to the 8080A. A write com-mand transfers data for one sectorfrom the microprocessor to the drive.A read-track command transfers allbytes of data on a track to themicroprocessor. A read-address com-mand transfers the next-encounteredidentification (ID) field to themicroprocessor, places the sector ad-dress into the sector register, andchecks the 2-byte cyclic-redundancy-check (CRC) field. During a write-track (format) command, themicroprocessor must supply all gap,ID-field, and data bytes except for ad-dress marks and CRC bytes.

Data transfers between the 8080Aand the floppy-disk drive can be per-formed using either direct memoryaccess (DMA) or programmed I/O,both of which are supported by theFD1771. I chose programmed I/O,because it is the simpler method of thetwo, and because it is fast enough forsingle-density disk drives. Withsingle-density recording, 1 byte istransferred every 64 ^s. An average8080A instruction takes 5 to 6 fis toexecute, so that about ten instructionscan be executed during the transfertime. This is enough time to gatherthe data and perform the requiredhousekeeping functions.

Initializing the FD1771

Before the FD1771 can executecommands, it must be initialized. Theprogram shown in listing 1 sets up thecontrol ports of the 8255 PPI so thatport A controls certain aspects of diskselection (as well as the MASTER -RESET ( MR ) pin of the FD1771);port B transmits the command, data,and status words for communication

between the 8255 and the FD1771;and port C controls data exchangesbetween the two devices. All com-mands and parameters come from thecomputer to the FD1771 through portB of the 8255. All data and status in-formation from the disk to the com-puter uses the same path.

Data transfers can be per-formed with either directmemory access (DMA) orprogrammed input/out-put.

The initialization routine of listing1 also checks the status of the FD1771and initializes all the registers. Thestack pointer is set to memory loca-tion hexadecimal OBEF. For large ap-plications, code for a disk-file librarycould be established in this routine aswell.

Formatting the Disk

Formatting the disk is a matter ofloading the track-address registerwith the point at which formatting isto begin, issuing the seek commandwhich moves the head to that loca-tion, loading the data register withthe format values, and issuing thewrite-track command to place thatformat on the disk.

Assuming that the formatting is tobegin at track 0 on the disk, for exam-ple, a seek routine (such as the onegiven in listing 2) is executed. First,the seek routine places the track ad-dress (which is 0) on port B of the8255. Then, holding line A0 high andAl low (see table 1), the routinecauses a write operation to theFD1771 to take place by_holding theREAD-ENABLE line (RE) high andpulling the WRITE-ENABLE line(WE) low. (See line 2 of table 1.)Similarly, the command code for aseek operation (hexadecimal 10) isplaced on port B of the 8255 and isdeposited into the command registerof the FD1771 by holding both A0and Al low and causing a writeoperation to take place. When theFD1771 receives the command byte,it executes the seek command, endingwith the read/write head in positionover the appropriate track (here,track 0).

At the end of the operation, theFD1771 automatically raises the logicstate on the interrupt line. At thesame time, a byte of status informa-tion that indicates whether the com-mand operation was successful ismade available to the 8080A.Although the byte of status informa-tion does not have to be interpreted,the status register must be read beforeanother operation can be performed.This is the purpose of the code mark-ed "status handshake" in listing 2.

To format each track, the write-track command must be issued. Thisis done by placing the command bytefor the write-track command (hexa-decimal F4) on port B of the 8255,setting lines A0 and Al low, andstrobing the write-enable line with ahigh-to-low transition. Once thiscommand is received, the FD1771waits for an index pulse from thedisk. The data register must then befilled with the contents of the entiretrack, 1 byte at a time. At the end ofthe track the disk drive sends the nextindex pulse, which causes an inter-rupt. To write the next track, a seek-to-track-1 operation is performed andanother write-track command isissued.

Floppy Disk Format

Although the FD1771 permits non-IBM data-storage formats, I chose touse a modified version of the stan-dard IBM format illustrated in figure3. This is a 16-sector-per-track,128-byte-per-sector format. In otherwords, each of the thirty-five tracksof the floppy disk contains sixteenrecords (see figure 3).

Each track starts with a gap, calledGl, of 16 bytes, each containing thevalue hexadecimal FF. Next come six-teen records, each of which containsan identification (ID) field, a secondgap (G2), a data field of 128 bytes,and an inter-record gap, G3, of 26bytes. The track is finished with ap-proximately 101 bytes of a final G4Agap field.

A 6-byte synchronization, or sync,section begins the identification fieldand is included to insure that the dataseparator is in phase with the data.The single-byte address mark (abbre-viated as AM) field contains a uniquecharacter that defines the beginningof the ID2 section; here, it has a valueof hexadecimal FE. The ID2 section

Text continued on page 100

86 May 1980 © BYTE Publications Inc

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MULTIVISION 1 (top module) is a get-started computerwith 5 MHz processor, 64K bytes of RAM (Random AccessMemory) and floppy-disk storage capacity of 700K bytes. It'savailable with a wide range of business application software. Weeven offer our own word processing package. A fully loadedMultivision 1 is list-priced at $3,785 without terminal.

MULTIVISION 2 (top and bottom modules) uses the newWinchester technology to provide 5M or 10M additional bytes ofhard-disk storage. List-priced at $7,995 for 5M bytes of disk, it isthousands less than other hard-disk systems.

MULTIVISION 3 (entire stack) turns your computer into amulti-user system with up to 256K bytes of RAM that supportsup to four display terminals. It allows four different parts of yourbusiness-i.e., accounting, marketing, purchasing, and shipping-to share data and simultaneously use the system. No othermicrosystem offers so much for so little.

Before you decide upon any small computer, look intoADDS Multivision. For years we've been the largest supplier ofdisplay terminals to computer giants.

Now we're making a system foryou.

For information, write: Systems Division, Applied DigitalData Systems Inc., 100 Marcus Boulevard, Hauppauge, N.Y.11787 Dealer inquiries invited.

CP/M is a registered trademark of Digital Research, Inc.

Applied Digital Data Systems Inc.

Circle 50 on inquiry card.

BYTE May 1980 87

Listing 1: Program header and initialization routines. This routine initializes the 8255 programmable peripheral interface and sets theread/write head in the floppy-disk drive to track 0.

HexadecimalAddress

HexadecimalCode

Label

0091

80008001800280030520

07 DOOBIO0B800798

0600060306060609060B060C060F0611

06120614061506170618

061B061C061E06IF062006220624

06270628062A062C062F0632

0600

I NIT

Instruction

Mnemonic

and Operand

Commentary

THIS PROGRAM IS DESIGNED TO PERFORM SEEKS,READS. WRITES AND FORMATS USING THEWESTERN DIGITAL FD1771 FLOPPY CONTROLLERCHIP INTERFACED TO AN SA400 AND A 8080 MPUCTRL EQU 91H

CONTROL WORD FORMAT:MODE=0

PORTA=DATA PORT (INPUTS)

PORTB=STATUS AND COMMAND LINES (OUTPUTS)PORTC= INPUTS. 0-3

;PORTC=

=OUTPUTS, 4-

7

PORTA

EQU

8000H

PORTB

EQU

8001H

;PORT A ADDRESS

PORTC

EQU

8002 H

;PORT B ADDRESS

CWR

EQU

8003 H

;PORT C ADDRESS

CHARS

EQU

520H

;CONTROL WORD ADDRESS;COMMAND CHARACTERS

SEEK

EQU

7D0H

ENTERED VIA CONSOLE

READ

EQU

0B1 OH

;SEEK TRACK ROUTINE

WRITE

EQU

0B80H

;READ SECTOR ROUTINE

PIN

EQU 798H

;WRITE SECTOR ROUTINE;PORT B SET AS INPUTS

ORG 600H

ROUTINE

INITIALIZE THE PPI (POWER UP)

MR ALWAYS =

1 AFTER INITIALIZATION v

NIT

LXI SP.0BFFH

SET THE STACK

31FF0B

CALL PIN

PORTB INPUTS

CD9807

LXI H.PORTA

PORTA ADRS

210080

MV1 A.01H

MR=0,DR SEL.MOT ON

PPI

3E01

MOV M,A

WRITE PORTA I

INITIALIZE

77

LXI D.PORTC

LOAD PORTC ADRS

110280

MVI A.O

RE,WE=1

3E0012

ST AX D

WRITE PORTC /

PPI INITIALIZATION DONE

RESTORE TO TRACK 0 IS AUTOMAT

IC

TRK0

3E0O

MVI A.00H

MR=1

77

MOV M.A

WRITE PORTA

0

3E08

MVI.A.08H

READ ENAB-STAT REG

12

ST AX D

(RE=0) WRITE PORTC

3A0180

LDA PORTB

READ PORTB—GETSTATUS

4F

MOV C.A

SAVE STAT REG

3E00

MVI A.OOH

RE=I (MR,WE=1)

12

STAX D

WRITE PORTC

79

MOV A,C

MOV STATUS TO A

E604

AN1 4H

GET TRAK 0 STATUS

FE04

CP1 4H

TRAK 0?

CAI206

JZ TRKO

NO

DRIVE NOW AT TRACK 0 — TEST R

=ADY

79

MOV A.C

RESTOR STATUS IN A

E680

ANI 80H

GET READY STATUS

FE80

CPI 80H

READY?

CA3506

JZ 1NTERP.

YES GO TO IDLE LOOP

010000

LXI B.OH

ERROR CODE

CD0007

CALL ERROR

88 May 1980 © BYTE Publications Inc

Circle 51 on inquiry card.

LIMITED

EDITION

Offered for the first time, Volumes II andIII of BYTE back issues, packed with articlesby your favorite authors, are a realcollector's item. Volume II contains issuesfrom January '77 thru December '77 andVolume III contains issues from January '78thru December '78. Each volume is priced at$100.

These gold embossed, hard-cover volumesare individually numbered with only 100 setsavailable. Orders will be handled on a first-come, first-served basis. Based on our quicksell-out of Volume I, we know that thislimited offer will sell rapidly. So fill out thecoupon below and rush your order to BYTEBOOKS today.

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Listing 2: Seek routine. This routine causes the read/write head to go to (or seek) the track specified by a 2-digit number entered fromthe system console.

Hexadecimal Hexadecimal Label Instruction Commentary

Address Code Mnemonic

and Operand

800080018002079307980769

0520

;THIS ROUTINE IS DESIGNED TO;DRIVE TO A TRACK SPECIFIEDCHARACTERS ENTERED BY ANPORTA EQU 8000H

PORTB EQU 8001H

PORTC EQU 8002H

POUT EQU 793H

PIN EQU 798H

STATUS EQU 769H

CHARS

EQU 0520H

SEEK THEBY THE 3RD & 4THOPERATOR.

PORT A ADDRESS

PORT B ADDRESS

PORT C ADDRESS

PORT B SET AS OUTPUTS ROUTINE

PORT B SET AS INPUTS ROUTINE

ROUTINE, CONVERTS STATUS TO

ASCII PRINTABLE DATA

COMMAND CHARACTERS ENTERED

VIA CONSOLE.

07 DO

07D007D307D407D507 D807D907DC07DD07DE07DF07E007EI

2A2205

7C

B7

F2DC07

7D

C3E207

7D

07

07

07

07

84

ORG 7D0H

FORM THE TRACK ADDRESS FROM THE 3RD & 4THCHARACTERS. 4TH CHARACTER MIGHT BE NEGATIVEIF ONLY ONE CHAR WAS ENTERED.

SEEK

TWO

LHLD CHARS + 2

MOV A,H

ORA A

JP TWO

MOV A,L

JMP NEWTRK

MOV A,L

RLC

RLC

RLC

RLC

ADD H

;GET BOTH CHARS

XFR LS CHAR

TERM ?

NO

LOAD SINGLE CHAR

YES

XFR MS CHAR

;SHIFT TO MS POSITION

;MERGE CHARS

;NOW PUT NEW TRACK ADDRESS INFDC DATA REGISTER

07E2

07E5

07 E8

07EB

07ED

07EE

07F1

07F2

07 F5

07 F7

07F8

07FA

07 FB

07FD

07FE

0801

0803

0804

0806

322008

NEWTRK

STA TRACK

SAVE TRACK ADDRESS >

CD9307

CALL POUT

PORTB = OUTPUTS

210280

LXI H,PORTC

GET PORT C ADRS

0603

MVI B.03H

A0,A1 = 1

70

MOV M,B

WRITE PORTC

3A2O08

LDA TRACK

TRAK ADRS

2F

CMA

INVERT FOR WD BUS

320180

STA PORTB

WRITE PORTB

0607

MVI B.07H

WRITE TO DATA REG

h COMMANDHANDSHAKE

70

MOV M,B

WRITE PORTC

0600

B.00H

70

MOV M,B

WRITE PORTC

INITIATE SEEK COMMAND

3E1F

MVI A.1FH

SEEK 40 MS STEP

2F

CMA

320180

STA PORTB

WRITE PORTB

0604

MVI B.04H

WRITE TO CMD REG

70

MOV M,B

WRITE PORTC

0600

MVI B.00H

RE,WE = I

70

MOV M,B

WRITE PORTC

;WAIT FOR END OF SEEKTHEN REPORT STATUS

Listing 2 continued on page 92

90 May 1980 © BYTE Publications Inc

Circle 52 on inquiry card.

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Listing 2 continued:

0807080A080B080D08IO08120813081608180819081A

CD9807

7E

E640

CA0A08

3 EOS

77

3A0180

0600

70

2F

E6I8

WAIT

CALL PINMOV A,MANI 40HJZ WAITMVI A.08HMOV M,ALDA PORTBMVI B.OOHMOV M,BCMAANI 18H

;WAIT FOR EN D OF SEEK

;STAT REG READ

;WRITE PORTC

;BRING STATUS

;RE,WE=1

;WRITE PORT B

; IN VERT

;SEEK AND CRC BITS

STATUSHANDSHAKE

081C08IF0820

CD6907

C9

0007 DO

TRACK

CALL

STATUS

RET

BYTEOEND SEEK

;REPORT TO CONSOLE

92 May 1980 © BYTE Publications Inc

Circle 54 on inquiry card.

RBI

R2l/0—The S-100 ROM,RAM Cr I/O Doord

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• 2K ROM • 1 Parallel I/O Port

• 2K RAM • 4 Status Ports

• ROM Monitor (Operating System)

ELECTRONIC CONTROL TECHNOLOGY'S R2l/0 is anS-100 Bus I/O Board with 3 Serial I/O Ports (UART's), 1Parallel I/O Port, 4 Status Ports, 2K of ROM with MonitorProgram and 2K of Static RAM. The R2l/0 provides a conven-ient means of interfacing several I/O devices, such as - CRTterminals, line printers, modems or other devices, to an S-100Bus Microcomputer or dedicated controller. It also provides forconvenient Microcomputer system control from a terminalkeyboard with the 8080 Apple ROM monitor containing 26Executive Commands and I/O routines. It can be used indedicated control applications to produce a system with as fewas two boards, since the R2l/0 contains ROM, RAM and I/O.The standard configuration has the Monitor ROM located atF000 Hex with the RAM at F800 Hex and the I/O occupies thefirst block of 8 ports. Jumper areas provide flexibility to changethese locations, within reason, as well as allow the use ofROM's other than the 2708 (e.g. 2716 or similar 24 pin de-vices). Baud rates are individually selectable from 75 to 9600.Voltage levels of the Serial I/O Ports are RS-232.

CPU

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2K

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Lj~r}

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MONITOR

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UART

STATUS

ft

UART

STATUS

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UART

STATUS

8 BIT LATCH_8 BIT LATCH

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*+#-.

STATUS

^J

5^£

S-100 BUS

SERIAL

TERMINAL/

PRINTER

#1

SERIAL

TERMINAL'

PRINTER

#2

SERIAL

TERMINAL/

PRINTER

#3

PARALLELDEVICE

8080 APPLE MONITORCOMMANDS

A-Assign 1/0

B -Branch to user routine A-Z

C -Undefined

D -Display memory on console in Hex

E -End of file tag for Hex dumps

F -Fill memory with a constant

G -GOTO an address with breakpoints

H -Hex math sum & difference

I -User defined

J -Non-destructive memory test

K -User defined

L -Load a binary format file

M-Move memory block to another

addressN -Nulls leader/trailer0 -User definedP-Put ASCII into memoryQ-Query 1/0 ports: Ql (N)-read I/O;

Q0(N,V)-send 1/0R -Read a Hex file with checksumS -Substitute/examine memory in HexT -Types the contents of memory in

ASCII equivalentU -Unload memory in Binary format

V -Verify memory block against another

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Listing 3: Read-sector routine. This routine causes the contents of a given sector of the current track (specified by a 2-digit numberentered from the system console) to be transferred from the disk drive to an area of memory starting at the location given by the valueof DATBUF, using decreasing memory addresses.

HexadecimalAddress

HexadecimalCode

Label

Instruction

Mnemonic

and Operand

Commentary

800080018002079307980769

05FF

0520

READ READ SECTOR ROUTINE

READ SECTOR ROUTINE INITIATES THE READ

COMMAND AND TRANSFERS ALL THE DATA FOR A

SELECTED SECTOR TO THE BOTTOM OF MEMORY

BEGINNING AT LOCATION 5FF

R,XX READ SECTOR, SECTOR ADRSPORTA EQU 8000H ;PORT A ADDRESS

PORTB EQU 8001H ;PORT B ADDRESS

PORTC EQU 8002H ;PORT C ADDRESS

POUT EQU 793H ;PORT B SET AS OUTPUTS ROUTINE

PIN EQU 798H ;PORT B SET AS INPUTS ROUTINE

STATUS EQU 769H ;ROUTINE CONVERTS STATUS TO

ASCII PRINTABLE DATADATBUF EQU 5FFH ;BEGINNING ADRS OF "READ"

DATA BUFFERCHARS EQU 520H COMMAND CHARACTERS ENTERED

VIA CONSOLE

0B10

ORG 0B10H

0BI0

0B13

0B14

0B15

0B18

0B19

0B1C

0B ID

0B1E

0B1F

0B20

0B21

0B22

0B25

0B28

0B2B

0B2D

0B2E

0B31

0B32

0B35

0B37

0B380B3A0B3B0B3D0B3E0B4I

0B43

2A2205

7C

B7

F21C0B

7D

C3220B

7D

07

07

07

07

84

327C0B

CD9307

210280

0602

70

3A7C0B

2F

320180

0606

70

0600

70

3E88

2F

320180

0604

70

READ LHLD CHARS+2

MOV A,HORA AJPTWOMOV A.LJMP SECTOR

TWO MOV A,L

RLCRLCRLCRLCADD H

SECTOR STA SECSTR

CALL POUTLXI H,PORTCMVI B.02HMOV M.BLDA SECSTRCMA

STA PORT BMVI B.06H

MOV M.B

INITIATE THE READ COMMAND

MV B,0MOV M,BMVI A.88HCMA

STA PORTBMVI B.04H

MOV M.B

GET BOTH CHARS

XFER LS CHAR

TERM?

NO

LOAD SINGLE CHAR

;XFER MS CHAR;SHIFT TO MS POSITION

MERGE CHARSSTOR SECTORPORTB OUTPUTSGET PORTC ADRSSECTOR REGISTERWRITE PORTCSECTOR ADRSINVERT FOR WD BUSWRITE PORTBWRITE TO SECTORREGWRITE PORTC

SEL CMD REGWRFTE PORTCREAD CMDINVRT FOR WD BUSWRITE PORTBISSUE READ TOCMD REGWRDTE PORTC

COMMANDHANDSHAKE

WAIT FOR END OF READ — THEN REPORT

Listing 3 continued on page 96

94 May 1980 © BYTE Publications Inc

POWER-ONED.C. POWER SUPPLIES

Now available for small systems applications

Power-One, the leader in quality open-frame power supplies, now offers a complete line of single, dual,and triple output models for small computer systems. Also available are special purpose models forFloppy Disk and Microcomputer applications.

Below are just afew popular examples of the over 90 "off the shelf" models now available from stock.

SINGLE OUTPUTSLOGIC POWER SUPPLIES

• 56 "off the shelf"models

•2V to 250V, 0.1Ato40A

• ± .05% regulation

• 115/230 VAC input

3A,w/OVP

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• Powers most populardrives

• Single/dual driveapplications

• 2-year warranty

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5V @ 2.5A, w/OVP-5V@0.5A, w/OVP24V @ 3A/3.4A PK

CP340

For one 5.25" Media Drive

$44.95 single qty.

CP205

For one 8.0" Media Drive

$69.95 single qty.

CP206

For two 8.0" Media Drives

$91.95 single qty.

12V/15V @ 0.25A

DUAL OUTPUT MODELS

• 15 "off the shelf"models

• ±5Vto ±24V,0.25Ato 6 A

• I.C. regulated

• Full rated to +50°C

i£iv

5V@2A, w/OVP9-15V@0.5A

1.7Aor1.5A

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25

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$44.95 single qty.

HBB15-1.5$49.95 single qty.

TRIPLE OUTPUTMODELS

• 10 "off the shelf"models

• 5V plus ± 9V to± 15V outputs

• Models from 16W to150W

• Industry standard size

5V @ 2A, w/OVP

± 9VtO ± 15V@0.4A

5V @ 3A, w/OVP±12V @ 1Aor±15V@0.8A

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Circle 55 on inquiry card.

BYTE May 1980 95

Listing 3 continued:

01344

0B46

0B47

0B4A

0B4D

0B4F

0B52

OB 54

0B55

0B58

0B59

0B5A

0B5B

0B5C

0B5D0B5E0B610B63

0B660B6S0B690B6B0B6C0B6D

0B70

0B710B740B760B77

0B780B7B

0B7C0B7E

0603

MVI B.03H

SEL DATA REG

70

MOV M,B

WRITE PORTC

CD9807

CALL PIN

PORTB = INPUTS

11FF05

LXI D.DATBUF

FWA OF DATA

0603

MVI B.03H

RE,WE=1

C35C0B

JMP DLOOP

3E0B

GD

MVI A.OBH

R£=0

DATA> TRANSFERSEQUENCE

77

3A0180

2F

MOV M,ALDA PORTBCMA

WRITE PORTCGET DATAINVERT DATA

12

ST AX D

SAVE IT

IB

DCX D

BUMP INDEX

70

MOV M,B

RE =1, PORTC

7E

DLOOP

MOV A,M

GET STATUSPORTC

B7

ORA A

DRQ = 1?

FA520B

JM GD

YES

E640

ANI 40H

INTRQ SET?

CA5C0B

;READ DONE

JX DLOOP— GET STATUS

NO j

3E00

MVI A.O

ADRS STAT REG '

77

MOV M,A

WRITE PORTC

3 EOS

MVI A.08H

STROBE RE=0

77

MOV M,A

WRITE PORTC

F.B227E0B

XCHGSHLD ISAVE

SAVE INDEX TODATA

. STATUSHANDSHAKE

EB

XCHG

RESTOR PORTCADRS

3A0180

LDA PORTB

GET STAT BYTE

0600

MVI B,0

STAT HANDSHAKE

70

MOV M,B

WRITE PORTC '

2F

CMA

.INVERT STATBYTE

CD6907

CALL STATUS

.REPORT STATUS

C9

RET

0000

SECSTR

WORD 0

SECTOR ADRS

0000

ISAVE

WORD0

DATA INDEXSTORAGE AREA

OB 10

END READ

Listing 4: Write-sector routine. This routine causes a section of memory to be written to a given sector on the disk. The sector numberis specified by a 2-digit number entered from the system console.

HexadecimalAddress

8000800180020793

0798

0769

0520

HexadecimalCode

Label

PORTAPORTBPORTCPOUT

PIN

STATUS

CHARS

Instruction

Mnemonic

and Operand

Commentary

WRITE WRITE SECTOR ROUTINE

WRITE SECTOR ROUTINE INITIATES THE WRITECOMMAND AND TRANSFERS ALL THE DATA FOR ASELECTED SECTOR

W.XX = WRITE SECTOR,SECTOR ADRS

EQU 8000HEQU 8001HEQU 8002HEQU 793H

EQU 798HEQU 769H

EQU 520H

PORT A ADRSPORT B ADRSPORT C ADRSPORT B SET ASOUTPUTSROUTINE;PORT B SET ASINPUTS ROUTINE;ROUTINECONVERTSSTATUS TO ASCIIPRINTABLE DATA;COMMAND CHAR-

Listing 4 continuedon page 98

96 May 1980 © BYTE Publications Inc

MicroQuote

Your personal computer becomesa window on Wall Street.

MicroNET, the personal computer service ofCompuServe, now offers MicroQuote, a compre-hensive securities information system.

With MicroQuote you can gain information froma data bank of over 32,000 stocks, bonds and op-tions from the New York, American, OTC and majorregional markets plus Chicago options. MicroQuotecontains price and volume data from January, 1974with cumulative adjustment factors and dividendinformation from January, 1968.

You can determine indicated annual dividends,earnings per share, shares outstanding, BETA fac-tors, open interest on options and amount outstand-ing on debt issues. MicroQuote can provide issuehistories on a daily, weekly or monthly basis andeven performs certain statistical analyses on thedata. It's a vital tool for any investor.

It's just part of the MicroNET service

MicroNET also allows error-free downloading ofsoftware via the new software exchange and execu-tive programs (now available for the TRS-80," AppleII* and CP/M" systems). It also provides electronic

mail service and can be accessed with a 300 baudmodem via local phone calls in more than 175 U.S.cities. Write for full details on how your microcom-puter can control one of the nation's largest andmost sophisticated time-sharing computer centersfor about 8 cents a minute!

TRS-80 is a registered trademark of Tandy CorporationApple II is a registered trademark of Apple Computer. Inc.CP/M is a registered trademark of Digital Research

Regional distributors and local dealers wanted.Inquire to Dept. R

Software authors: MicroNET seeks to license qualityprograms for software exchange. Write toDept. S

UMicraHIETL

Mail to: Dept: B

f UTTI1111 ^firx/Ck Personal Computing DivisionUUllipuaCl VC 5000 Arlington Centre Blvd.Columbus, Ohio 43220

Circle 56 on inquiry card.

BYTE May I960 97

Listing 4 continued:

ACTERS ENTERED

VIA CONSOLE

OB80

ORG 0B80H

0B80

2A2205

READ

LHLD CHARS

+ 2

GET BOTH CHARS

OB83

7C

MOV A,H

XFER LS CHAR

0B84

B7

ORA A

TERM?

0B85

F28COB

JPTWO

NO

OB88

7D

MOV A,L

LOAD SINGLECHAR

0B89

C3920B

J MP SECTOR

0B8C

7D

TWO

MOV A,L

XFER MS CHAR

0B8D

07

•

RLC

SHIFT TO MSPOSITION

0B8E

07

RLC

0B8F

07

RLC

0B90

07

RLC

0B91

84

ADD H

MERGE CHARS

0B92

32E50B

SECTOR

STA SECSTR

STOR SECTOR '

0B95

CD9307

CALL POUT

.PORTB OUTPUTS

0B98

210280

LXI H, PORTC

,GET PORTC ADRS

0B9B

0602

MVI B.02H

.SECTORREGISTER

0B9D

70

MOV M,B

;WRITE PORTC

0B9E

3AE50B

LDA SECSTR

SECTOR ADRS

0BA1

2F

CMA

INVERT FOR WDBUS

0BA2

320180

STA PORTB

.WRITE PORTB

COMMAND

OBA5

0606

MVI B.06H

:WRITE TO ( HANDSHAKE

SECTOR REG

0BA7

70

MOV M,B

WRITE PORTC

INITIATE THE READ COMMAND

OBA8

O600

MVI B,0

SEL CMD REG

OBAA

70

MOV M.B

WRITE PORTC

OBAB

3EA8

MVI A.0A8H

WRITE CMD

OBAD

2F

CMA

INVRTFOR WDBUS

OBAE

320180

STA PORTB

WRITE PORTB

OBB1

0604

MVI B.04H

ISSUE READ TOCMD REG

Listing 4 continued

OBB3

70

MOV M,B

WRITE PORTC /

on page 100

There is no other mainframe that compares with theperformance and reliability of a TEI mainframe. Its uniquedesign enhances substantially the reliability of any S-100computer system by providing high efficiency power,brown out protection, line noise rejection and a sophisticat-ed high-speed bus packaged in a durable enclosure.

TEI manufactures the broadest selection of S-100mainframes ... 8,12 and 22 slot, desk top and rackmountmodels. Whether your requirements are standard or cus-tom, TEl's extensive manufacturing capacity and know-how can solve your mainframe problems today!

Successful OEM's, system integrators and computerdealers worldwide rely on TEI mainframes and enjoy agood night's sleep knowing that their systems are stillrunning. Call TEI today... you too can enjoy a goodnight's sleep!

More than a decadeof reliability.

5075 S. LOOP E., HOUSTON, TX. 77033(713) 783-2300 TWX. 1 910-881-3639

98 May 1980 © BYTE Publications Inc

Circle 57 on inquiry card.

The Universal™

Intelligent Controller and

the 5 Little Plugs

This little pluggywenttotheS-100,This little pluggystayed with fixed disThis little pluggyhad floppies,

This little pluggysupported tape,

And this little pluggy

went all the way home,

,.

I

flJ'l I II

•^mm^K^Kmmmmi^^^ w

j||jj|||jPip||)|j||P^

Five plug sets is all it takes for simultaneous, Call or write for full information. Data Man-multi-device storage control. DML's Univer- agement Labs, 2148 Bering Drive, San Jose,sal™ Intelligent Controller makes it possible. CA 95131 (408) 248-2104.

■ S-100 Bus, with CP/M* support *CP/Misa,rademarkofDi§ilaIResearch

■ Plug adaptable device support

■ Control of up to 8 storage devices: 4 fixeddisks, 4 floppy or tape cartridge drives

■ IEEE DMA or port transfer data management labs

Circle 58 on inquiry card. byte May i?80

99

Listing 4 continued:

WAIT FOR END OF READ — THEN REPORT

0BB4

0603

MVI B.03H

SEL DATA REG \

0BB6

70

MOV M,B

WRITE PORTC

0BB7

110180

LXI D,PORTB

PORTB ADRS

OBBA

0603

MVI B.03H

RE,WE=1

OBBC

C3C70B

JMP DLOOP

OBBF

3E8D

GD

MVI A.8DH

LOAD DATA

0BC1

2F

CMA

INVRT DATA

DATA

0BC2

12

STAX D

WRITE PORT B

r TRANSFER

0BC3

3E07

MVI A.07H

WE=0

HANDSHAKE

0BC5

77

MOV M,A

WRITE PORTC •

0BC6

70

MOV M,B

RE =1,PORTC

0BC7

7E

DLOOP

MOV A,M

GET STATUSPORTC

0BC8

B7

ORA A

DRQ = 1

0BC9

FABFOB

JM GD

YES

OBCC

E640

ANI 40H

INTERQ SET

OBCE

CAC70B

READ DONE

JZ DLOOP— GET STATUS

NO '

0BD1

CD9807

CALL PIN

PORTB INPUTS '

0BD4

3E00

MVI A,0

ADRS STAT REG

0BD6

77

MOV M,A

WRITE PORTC

0BD7

3E08

MVI A.08H

STROBE RE=0

STATUS

0BD9

77

MOV M,A

WRITE PORTC |

HANDSHAKE

OBDA

3A0180

LDA PORTB

GET STAT BYTE

OBDD

0600

MVI B,0

STAT HANDSHAKE

OBDF

70

■

MOVM.B

WRITE PORTC /

OBEO

2F

CMA

INVERT STATBYTE

0BE1

CD6907

CALL STATUS

REPORT STATUS

0BE4

C9

RET

OBE5

00000B80

SECSTR

WORD0END READ

SECTOR ADRS

PHYSICAL INDEXHOLE

~n

"

Gl

16FF

EATEDG2

11FF

G4A

101

FF

«—ID FIELD ►

SYNC|AM|ID2|CRC

6 14 200 FE * *

G3

26FF

NUMBER OF BYTES

BYTE VALUE

IN HEXADECIMAL

SYNC | AM |DATA | CRC6 1 128 2

00 FB * *

WG OFF1

FF

UPDATE WRITE _

CY CHECK FIELD3YTE

LEI

IDAMCRCWG

•END:

IDENTIFIC;

ADDRESS N

CYCLIC RE

OFF WRITE-GAT

TIONARK

DUNDANE-OFF

Figure 3: Format of data as recorded on one track of the disk drive. Each track containssixteen records, each of which contains 128 bytes. Each record consists of an identifica-tion (ID) field followed by a data field. The columns marked with an asterisk representfields with contents that vary from record to record.

Text continued from page 86:

contains the following: track address,side-select byte (set to 00 here), sectoraddress, and sector length (set to 00here because the sector length is con-stant); each field is 1 byte long. Thecyclic-redundancy-check (CRC) sec-tion contains a 2-byte value thatserves to check the accuracy of theprevious bytes as written onto thedisk. A command byte of hexa-decimal F7 sent to the FD1771 con-troller causes it to generate and writethe CRC bytes.

The data field also begins with async section. The address mark forthis section, hexadecimal FD, is a dif-ferent value than for the sync sectionin the identification field. A data sec-tion of 128 bytes follows and can befilled with any desired data. The lastsection within the data field is thewrite-gate-off (WG-off) byte, whichallows the head an area in which to be

100 May 1980 © BYTE Publications Inc

■"e

standard on our 900 SERIES

microcomputer system...under H.OOO.OO*

Having so much disk capacity as standard in a low costmicrocomputer system is reason enough to make the900 Series your logical choice — but the fact is, it's onlyone of the reasons why this system offers the bestprice/performance value of any now on the market.There's also a simple modular design, a reliable singleboard computer, dual flexible disk drives, a versatiledisk operating system, plenty of room for expansion,and attractive quantity discounts — plus a lot more.

Just check out these standard features and expan-sion capabilities.STANDARD ON THE 900 SERIES:

□ Single board microcomputer: Z80 based; 4 MHz.operation; DMA controlled disk access.

□ Dual eight inch flexible disk drives: on-line formattedcapacity of 2.5 megabytes expandable to 5 Mb; accesstime of 3 milliseconds track-to-track; 8000 hour MTBFreliability rating.

□ IBM 3740 format compatible

□ 48 kilobytes of dynamic RAM,expandable to 65 Kb.

□ CP/M* Disk Operating Systemwith assembler, editor and debugsubsystems.

□ RS232 or TTY serial port for systemconsole.

□ Parallel line printer port(Centronics-compatible).

DESIGNED FOROPTIMUM RELIABILITYAND EASY SERVICING

Single board designQuad-density flexible disk drivesTurn-key operation and securityExpansion capabilitiesIndustrial quality construction

'Unit price (S3.996.) in small quantities; pleasecontact factory for complete discount scheduleCP.'M" is a registered trademark of Digital Research

OPTIONS FOR THE 900 SERIES:

□ Disk expansion: up to 5 Mb formatted capacity.

□ Serial I/O expansion: two additional RS232 ports(serial printer, modem, etc.)

□ S100 bus adaptor for system expansion.

□ Multi-user operation

□ Hard disk subsystem

AVAILABLE SOFTWARE FOR THE 900 SERIES:

□ High level languages include: BASIC, FORTRAN,COBOL and PASCAL.

□ Application packages include: Inventory, WordProcessing, GL, AR, AP and Payroll.

the Quay 900 Microcomputer System offers themost complete package for the money

QUASI

CORPORATION

P.O. Box 386, Freehold, New Jersey 07728 ■ (201) 681 -8700Factory: Route 34, Wall Township, New Jersey 07719

DISTRIBUTOR AND REPRESENTATIVE INQUIRIES WELCOME

Circle 59 on inquiry card.

$$$SAVE$$$TRS-80*/ZENITH/APPLE/ MATTELATARI COMPATIBLE HARDWARE

DISK DRIVES

More capacity than Radio Shack 35 Track (80 KBytes) drives. Fully assembled and tested.Ready to plug-in and run the moment youreceive it. Can be intermixed with each otherand Radio Shack drive on same cable. TRS-80*compatible silver enclosure.90 DAY WARRANTY. ONE YEAR ON POWER SUPPLY.

FOR TRS-80*

CCI-100 5V4", 40 Track (102K Bytes) for Model I

CCI-200 5V4", 77 Track (197K Bytes) for Model I

CCI-800 8" Drive for Model II (Vs Meg Bytes)

For Zenith Z89

CCI-189 5Vt", 40 Track (102K Bytes) add-on drive

Z-87 Dual 5Va" add-on drive system

DISKETTES — Box of 10(5Va")~ with plastic

16K MEMORY UPGRADE KITS

for TRS-80*, Apple II, Sorcerer (specify)

PRINTERS NEC Spinwriter

Letter Quality High Speed Printer

Includes TRS-80* interface software, quickchange print fonts, 55 cps, bidirectional,high resolution plotting, graphing, propor-

$314$549$795

$394$1095

library case $24.95

$59.95

tional spacing $2479

With Tractor Feed $2679

779 CENTRONICS TRACTOR FEED PRINTER $995

Same as Radio Shack line printer

737 CENTRONICS FRICTION & PIN FEED PRINTER $849

Text quality matrix , proportional spacing

730 CENTRONICS FRICTION & PIN FEED PRINTER $640

7x7 matrix

P1 CENTRONICS PRINTER $349

Same as Radio Shack quick printer

PAPER TIGER (IP440) $995

Includes 2K buffer and graphics option

TI-810 $1599

Upper and lower case, parallel and serial, paper

tray and TRS-80* interface software

OKIDATA Microline 80 Friction and pin feed $645

Tractor Feed, friction, and pin feed $745

EATON LRC 7000 + 64 columns, plain paper $349

COMPLETE SYSTEMS

TRS-80* LEVEL 11-16K with keypad $722

TRS-80* Expansion Interface $274

ZENITH Z89 all-in-one computer $2295

ZENITH Z19 $740ATARI 400 $549 ATARI 800 $999

MATTEL INTELLIVISION $299

DISK OPERATING SYSTEMS

PATCHPAK#4byPercom Data $ 8.95

CP/M for Model I, Zenith $145.00

CP/M for Model II, Altos $245.00NEWDOS Plus —with over 200 modifications 35 Track $89.00and corrections to TRS-DOS 40 Track $99.00

CAT MODEM Originate and answer same asRadio Shack Telephone Interface II

$157.50

The CPU SHOP

TO ORDER CALL TOLL FREE 1-800-343-6522

Massachusetts residents call (617)242-3361

5 Dexter Row, Dept. B-5, Charlestown, MA 02129

Hours: 10AM-6PM (EST) M-F(Sat. till5)

Massachusetts residents add 5% sales tax

Freight collect, F.O.B. Charlestown

*TRS-80 is a trademark of Tandy Corporation ViSA

Prices subject to change without notice.

turned off from the write modewithout destroying any valid data.Although a hexadecimal FF is writtento this field, we do not care whatvalue resides in the WG-off field onthe floppy disk.

Once the disk is formatted, readingor writing can begin. The read andwrite commands are similar in severalrespects to other commands such asthe seek command. Each must be partof a software routine in which a com-mand parameter is loaded into thedata, sector, or track register, and thecommand itself is loaded into thecommand register. All commandsalso generate an interrupt signal attheir completion. This interrupt mustbe reset through a status handshakeroutine that reads the status register.

However, the read and write com-mands differ from commands like theseek command in the following onerespect: data must be transferred. Forexample, a write command, in a data-transfer routine like that presented inhexadecimal locations 0BB4 thru0BCE of listing 4, places a byteof data in port B and points the ad-dress pointers (lines A0 and Al) tothe data register. When the FD1771raises the DRQ line, the WRITE-ENABLE line is brought low. Thebyte of data, which is placed in theFD1771 data register, is transferredfrom the FD1771 to the disk. The8080A places another byte in the portand pulls the WRITE-ENABLE linelow again when the FD1771 signalsthat it is ready to accept another byteof data. A similar procedure isfollowed for a read command (seelisting 3), except that this commanduses the READ-ENABLE line.

This concludes our discussion ofthe hardware and software necessaryto interface a Shugart SA400 diskdrive to an 8080A-based microcom-puter system. Additional applicationinformation is given in the applica-tion notes available from the com-panies listed in the references. ■

References

1. SA400/450 Minifloppy Diskette StorageDrives with an 8080A/FD1771 Single Den-sity System Application Bulletin, ShugartAssociates, 415 Oakmead Parkway,Sunnyvale CA 94086

2. FD1771 Floppy Disk Formatter/ControllerData Sheet, Western Digital Corporation,3128 Red Hill Ave, POB 2180, NewportBeach CA 92663

3. Intel 8080 Microcomputer Systems User'sManual, Intel Corporation, 3065 BowersAve, Santa Clara CA 95051

102 May 1980 © BYTE Publications Inc

Circle 179 on inquiry card.

Circle 60 on inquiry card.

with IVDCX

PROGRAMMING THE 6502

This book is designed as a progressive,step-by-step approach to assembly lan-guage programming-with excercisesdeveloped to test the reader at everystep. Learn to write complete applica-tions programs. Features: Programmingand addressing techniques, input/outputtechniques and devices, applicationexamples, data structures, programdevelopment and more.

Ref.C202 SI 2.95

6502 APPLICATIONS BOOK

This title presents real life applicationtechniques for any 6502 based micro-computer board. Programs presentedcover building a complete home alarmsystem, electronic piano, motor speedregulator... and more. Learn techniquesranging from simulated traffic control toanalog-digital conversion. The KIM-1,SYM-1 and AIM 65 are thoroughlycovered.Ref.D302 $12.95

6502 GAMES

Designed as an educational text onadvanced programming techniques,this book presents a comprehensive setof algorithms and programming tech-niques for common computer games. Allof the programs were developed for the6502 at the assembly language level.Learn how to devise strategies suitablefor the solution of complex problemscommonly found in games.

Ref.G402 $12.95

Please send me

Name

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Address

City

— — — — — — — — — —. TOORDER:

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Please send me your detailed catalog I AVAILABLE AT BOOK AND COMPUTER STORES EVERYWHERE

I

A Graphics Text Editor for

Music

Part 2: Algorithms

Randolph Nelson

2039 West Artesia Blvd

Apt 121

Torrance CA 90504

The Commands

With what commands should theeditor provide the user in order tomake the program easy to use, andhow does the nature of these com-mands affect the structure of the pro-gram?

Mode Commands

We begin to answer this questionby distinguishing three major ways inwhich the user will use the program.The first is when the user creates ascore of music. Here the editor mustestablish a file for the score and allowthe user to overwrite the defaultvalues for the music, such as the keyand time signatures. The second ma-jor use consists of editing the score.The program needs to providefacilities for locating the measure tobe edited, reformatting the pagesafter editing, and writing the finishedversion out to a file. The third andhardest facility the editor must pro-vide is the ability to display the scoreon the screen.

A multitude of problems must behandled automatically by the editorin adjusting the format of the score as

Note

The figure numbering sequence is con-tinued from part 1 which appeared in theApril 1980 BYTE.

it will appear on the screen. Theabove discussion leads to a definitionof three separate modes of operationfor the editor called the CREATE,EDIT, and DISPLAY modes.Switching between modes is done byissuing a command through thegraphics tablet as discussed in part 1.The editor also switches modesautomatically to display the contentsof a measure while the user creates oredits the score.

Location Commands

Commands must be provided toallow sequential passage through thescore. In order to do this, the usermust first set a symbolic-operationmode which determines the units tobe used as increments in movingthrough the score. These units arepages, lines, measures, or characters,and are set via commands on thetemplate. For example, suppose youare located on page two, line one,measure three, and character twenty-one of the score, and you wish to editpage five, line four, measure one, andcharacter three. The following se-quence of commands will accomplishthis:

1. Touch page. This sets the in-crements to pages, and sets theline, measure, and character valuesto one.

2. Touch forward three times. Thispositions you on the first line,

measure, and character of pagefive.

3. Touch line. Touch forward threetimes. You are now at the firstmeasure of line four.

4. Touch character and touch for-ward two times.

If you are editing the end of a unit,it is often faster to back up. If youwere editing the last character,number thirty-seven, of measure oneabove, you could go to measure twoand then back up one character ratherthan going forward from measureone, thirty-seven times. If the pro-gram is to provide this flexible loca-tion scheme to the user, it should beeasy to determine the location of thepage, line, measure, and character atany place in the score. A look back atthe data structures indicates that thiswas accomplished using doubly-linked pointers between the scorearea arrays.

Edit Commands

The program must support allediting features that allow easy textmanipulation. Commands to insert,delete, replace, or move pages,measures, lines, or characters must beprovided, as well as methods ofsearching the text for patterns ofmusic. These facilities require a set ofroutines that will automatically ad-just the paging of the music afterediting.

104 May 1980 © BYTE Publications Inc

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Exit Commands

After editing a measure, the usereither wants the version to become apermanent part of the score, orwishes to inform the program to ig-nore any changes made. This is thefunction of the EXIT and NULL-EXITcommands on the template. Note thatthe exit command must transfer thecontents of the work area to the scorearea and make the necessary formatchanges while the NULL-EXIT simplydoes nothing.

Symbols

Music abounds with symbols. The

template shown in part 1 indicatesonly a few. The actual design allowsfor one hundred different symbols. Inorder to avoid cluttering the templateyou would have to cull the necessarysymbols for the type of music that isbeing scored. To transfer from onenotational style to another is not adifficult task, since only the templateand interface program would have tobe changed. The main portion of theeditor is protected from such altera-tions.

Output

The hardest problems of the editor

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are related to displaying the musicalscore on the screen in a pleasing anduseful format. I will touch on threeclasses of problems, and outline theirsolutions in this section.

Dimension Problems

This set of problems is caused bythe physical dimensions of the screenoutput. The actual physical dimen-sions of the height and length of thescreen are fixed, and you must workaround their limitations. Since mostgraphics screens represent points in acoordinate system, the maximum andminimum absolute coordinates forthe X and Y axis are set.

In order to achieve a flexibledesign, no commitment should bemade to any of these machine-dependent characteristics. Instead,you should work in a virtual coor-dinate space controlled by the editor,and write another interface programto handle the conversion of coor-dinates in the virtual space to the ac-tual screen coordinates. Every dimen-sion that is given will then represent adimension of the virtual space in theeditor. Since the option of determin-ing the size of a score of music shouldbe left to the user, you must under-stand that all dimensions are subjectto scaling factors that will be set bythe user on entrance to the program.With these considerations in mind, Iwill now discuss three problems andtheir solutions.

1. The Spacing Problem for theStaff

How are the dimensions for thestaff, notes, and symbols determined?The solution was found by takingmeasurements from scores of musicand determining the standard sizes.Figure 5 shows the dimensions of thestaff and lists the dimensions forother symbols. Note that all dimen-sions are given in terms of LSPACE,which is the distance between thelines of the staff.

2. The Length of the MeasureProblem

How do you assign a virtual lengthto a measure? Although each measurehas the same number of beats, theirlengths can differ radically. Observein figure 7 that the length betweennotes of the same value is not alwaysequal. This eliminates a simplemethod in which you would assignvirtual lengths to specific note values

106 May 1980 © BYTE Publications Inc

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Circle 63 on inquiry card.

BYTE May 1980 107

-LLINE-

f^t

10 X LSPACE

NOTES:

j

«

#

S

1

1

a

i,

™ 1

INTER = 9 X 1/4 X LSPACE

STEM = 3 X LSPACE

OVAL LSPACE

fc

g PP

DISTANCE BETWEEN BARS = LSPACE

ALL NOTE SYMBOLS = LSPACE

Figure 5: Dimensions of the musical staff, notes, and symbols. AH dimensions are givenin terms of LSPACE, the distance between the lines of the staff.

and determine the total length of themeasure by summing their values. Amodified approach to this simplescheme can be adopted, however.You must first determine theminimum distance between notes thatallows sharps and flats to be inserted,while still preserving readability. Thisdistance can be fine-tuned to the eyeof the user, but it is approximatelynine-fourths the distance between thelines of the staff, or (%)XLSPACE.This dimension will be called the in-ternote distance, denoted by INTER.Second, a beaming group is definedas a set of notes that are connected bybeams. Later I will discuss a routinethat determines beaming groups inthe measure. Assume here that thejob has been done. Next, a code for

each possible note value is deter-mined (this code was actuallydeveloped much earlier and is usedthroughout the program in most ofthe data structures). This informationis shown in table 5. Notice that all thevalues are integer quotients of 20160.There are several reasons for this par-ticular encoding scheme. First, theeditor allows for twenty-six differentnote values. In order that the sub-groupings of these notes add up tocorrect total values, each note musthave the same common denominator.The value 20160 fulfills the require-ment. The code for one beat is 5040.Other reasons for this encoding con-cern the eventual placement of thenotes in their proper screen locations.The total length of the measure is

Figure 6: An example of a rarely occurringmusical symbol. Of the many thousandsof symbols which are used to com-municate different forms of expression,some are used only infrequently. This par-ticular symbol is found in piano music. Itdirects the performer to reach inside theinstrument and strike the string cor-responding to the indicated note with amallet.

now the sum of the lengths of all ofthe beaming groups of that measureplus the lengths of the rests. Thealgorithm for determining the lengthfor the beaming groups can now bestated:

1. Determine the total number ofbeats for the beaming group. Thiscan be done by summing the codesfor all the notes in the group anddividing by 5040, the value for onebeat. Let this value be NUM.

2. Find the minimum value for thebeaming group. Call this MIN.

3. Determine the number of notes re-quired if the total number of beatswere to be taken up by theminimum note. This is simplyNUM / MIN.

4. Multiply this number by the inter-note distance. Thus you finally getthe length, which is equal to (NUM/MINX INTER.

You can now perform the aboveroutine for all of the beaming groupsof the measure and sum up thelengths, with rests included. The totalvalue represents the virtual length of

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108 May 1980 © BYTE Publications Inc

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This board is very similar to the PLUS card. It differs in that itsbank select can use any of 256 output port addresses and it can beaddressed on 16K boundaries only. Pricing is the same as for thePLUS.

8/16 RAM

This board was designed for the 1980s. It is configured as 16K by8 bits when accessed by an 8-bit processor and configured 8K by16 bits when used with a 16-bit processor. The configurationswitching is automatic and is done by the card sampling the"Sixteen Request" signal sent out by all 16-bit CPU boards. Thecard has all the high noise immunity features of the PLUS andAPEX as well as "extended addressing". Extended addressing is areplacement for bank select which makes use of a total of 24address lines to give a directly addressable range of over 16megabytes. (For older systems, a switch will cause the card toignore the highest 8 address lines) This card ensures that yourmemory board purchase will not soon be obsoleted. It comes with200 nsec. memory chips only and is guaranteed to run without waitstates with our 8086 CPU using an 8 Mhz. clock. Prices: 1-4, $445;5-9, $345.

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BYTE May 1980 109

Whole

Dotted Half

Half

Quarter

Dotted Quarter

Dotted Eighth

Eighth

Dotted Sixteenth

20160

15120

10080

5040

7560

3780

2520

1890

JJ.J

n

JETS

Sixteenth

1260

Dotted Thirty-second 945

Thirty-second

Sixty-fourth

630

315

Triplet with dotted eighth 2520

Triplet

1680

Sextuplet with dotted

sixteenth 1260

Sextuplet

840

m

3

J. j J J J J

6

J J J J J J

Others: Fifth 1008, Seventh 720, Ninth 560, Tenth 504, Eleventh 458, Twelfth 420, Thirteenth 387, Fourteenth 360, Fifteenth 336.

Table 5: Additional musical symbols.

the measure. This is stored in thecharacter array of the score area.

3. The Line Length Problem

With different sized measures, howdo you determine the number ofmeasures that will fit on each line,thus assuring that the bar lines at theend of each line are aligned? The dif-ficulty of this problem is increased bythe fact that not all of the space in aline is used. Each line of music startswith a clef, key signature, and timesignature. Every bar line of everymeasure is bounded by empty space.(Refer to figure 5.) All of these spacesmust be accounted for in determiningthe number of measures that can fiton each line.

Assume that the total length of theline in virtual space is LLINE. Thefirst part of that space must beallocated to the clef and signatures;this will be called LWASTE. The totalusable virtual space, LUSABLE, isthen equal to LLINE-LWASTE. Thewasted space around each measurewill be called LMSRWST. If N

measures are on the line, thenNX LMSRWST space has beenwasted in these measures. Now sup-pose that you are positioned at thefirst measure that will go on the line.You know the virtual lengths ofthis measure and all that follow.Denote the sum of the lengths of thesefirst N measures as SUMN. The prob-lem is then to find the largest N suchthat:

LUSABLE > SUMN+N X LMSRWST

This says that you want to find thegreatest number of measures that canbe put on the line before going pastthe end of the line. In general, themeasures will not fit perfectly on theline; therefore there will be excessspace at the end. This excess must bedistributed equally among themeasures, and to do this you mustfind a scaling factor to transform eachX coordinate of the measure into anew coordinate. This scaling factorcan be easily determined. Let EXCESSbe the excess space at the end of theline. It is equal to LUSABLE —

SUMN -NX LMSRWST. The scal-ing factor then is simplyLUSABLE/(LUSABLE - EXCESS).The solution to the line length pro-blem is shown in algorithmic form inlisting 1.

Beaming

Before this problem can be for-mulated I will review some of thequestions that must be answeredwhen writing music on the page.These are various conventions usedfor writing music. The following listsa few of these problems.

Stems Up or Down?

You must first decide if a group ofeighth or sixteenth notes will be un-derbeamed or overbeamed (ie:whether the ligature is placed at thetop or bottom of the note stemswhich point up or down, respective-ly). The easiest solution to this prob-lem consists in finding the maximumnote displacement from the centerline of the staff and then drawing thenote stems in that direction. There are

110 May I960 © BYTE Publications Inc

several exceptional cases for this sim-ple algorithm. For example, if theprevious group of notes was under-beamed and the maximum displace-ment of the next group is above themiddle line of the staff (but not bymuch), the score will read easier if thegroup is underbeamed rather thanoverbeamed.

Determining Beam Inclination

Note in figure 7 that the ligature in-clination of beaming groups is notalways the same. To determine theangle of the beam, you must find theheight difference between the stems ofthe maximum note and the minimumnote. For each octave of this dif-ference, increase the height of the tiltby one unit. Notice that the tilt can be

either up or down. In the followingdiscussion I will talk about one of thefour cases: underbeamed and tiltingupward. The other three cases areeasy modifications to the algorithms.

Determining the Stem Lengths

The length of the stems from thenotes depends on several factors.Suppose you have an underbeamed,upward-inclined beaming group. Theshortest note stem must be at least acertain minimum length for readabil-ity. Once this distance is set, deter-mine the lengths of the stems for theother notes of the beaming group.These distances depend on the loca-tion of the note and the angle of thebeam. Although the algorithms arequite involved, they basically consist

Listing 1: Solution to the line-length problem in algorithmic form.

1. LUSABLE = LLINE - LWASTE

2. N = 1 SUMN = Virtual length of first measure

3. VALUE = SUMN + NxLMSRWST

IF LUSABLE < VALUE THEN GO TO 4

N = N +1

SUMN = SUMN + VALUE of virtual length of Nth measure

GO TO 3

4. EXCESS = LUSABLE - VALUE

LSCALE = LUSABLE / (LUSABLE - EXCESS)

5. Store scale into the scale portion of the line array for future use when displaying themeasure.

Listing 2: Algorithm used to determine whether a group of notes should be under oroverbeamed.

MINX, MINYMAXX, MAXY

1. Find the minimum note in the beaming group.Find the maximum note in the beaming group.Let OCTAVE be the height of an octave.

Let MID be the height of the middle note of the staff.

Let STEM be the minimum length of a stem.

Let LENGTH be the virtual length of the beaming group.

2. IF (MAX - MID) >; (MID - MIN) then overbeam, ELSE underbeam.Assume underbeam.

3. TILT = (MAX - MIN) / OCTAVE (integer division)

4. For each note in beaming group:Get coordinates into NOTEX, NOTEYM = TILT / LENGTH

B = (MINY - STEM) - MINX x M

The height of the stem for this note is then egual to NOTEY - M x NOTEX

Listing 3: Algorithm to determine the beaming groups.

1. BEATCOUNT = 0

MEASURECOUNT = Number of beats to a measure times 5040.

2. BEATCOUNT = BEATCOUNT + 5040IF MEASURE < 0 GO TO 5

3. Get value of next note into NOTEVALBEATCOUNT = BEATCOUNT - NOTEVALMEASURECOUNT = MEASURECOUNT - NOTEVAL

4. IF BEATCOUNT < 0 THEN output group and GO TO 2.IF encountered a rest THEN output group and go to 3

5. Finished with measure, either continue or stop.

of solving equations to find the in-tersection point for the lines of thestems and the beam. A completedescription of an example with all theequations is given in figure 8.

The algorithms for each of theseproblems are not difficult, and for themost part they consist of only a fewinstructions. However, the excep-tional cases which make the musicmore readable are complex andtedious. Given the ad hoc nature ofmusical notation there seems to be nomechanical way to eliminate these ex-ceptional cases. Let me briefly outlinethe basic algorithms. Once again, youassume that you have a routine thatprovides the beaming groups and thatyou are dealing only with anunderbeamed upward-inclinedgroup.

The beam-characteristic algorithmis shown in listing 2.

Next I will discuss how to deter-mine the beaming groups. The basicstrategy is to collect notes with flagsuntil one either goes past a beat or en-counters a rest. Then output a beam-ing group, and if a rest is encounter-ed, continue within the beat to collectthe remaining notes of the beat. Onlyin cases of syncopated rhythms willbeaming groups cross over a beat. Imight add that this is the reason forthe strange initialization:

BEATCOUNT =BEATCOUNT+ 5040

in step 2 of the algorithm, for ifBEATCOUNT comes back negativefrom step 4, a beat has been crossedover. The algorithm is shown inlisting 3.

Symbol Problems

Several ways are presented forroutines that draw the notes and sym-bols on the screen. You must keep inmind that the eventual size of thesymbols is left to the discretion of theuser, and the program must thereforeallow for scaling. Scaling sometimesdistorts characters, so the editor musthave procedures to keep this distor-tion within a readable limit. I foundthat for symbols consisting mostly ofstraight lines, simply storing a set ofrelative points and drawing lines be-tween them is sufficient. For symbolsthat are curves, such as the G clef, abetter approach is to use a spline-fitting routine to draw the symbol.

May 1980 © BYTE Publications lnc 111

I

fe£

Figure 7: Sample of a musical score, in this case part of a bourree by J S Bach. Note the difference in note spacing and in angles ofbeams.

0(NOTEX,

NOTEY )

0

(MINX, MINY)

0

STEM

Tl

LT

—" ' (MINX, MINY-STEM)

'

-LENGTH-

Figure 8: Calculating the equation of the line segment forming a beam. The standardslope intercept equation Y = mX + b is used. We know that the slope is M =TILT/LENGTH, and that the value of one point on the line is (MINX, MINY-STEM).Fitting this to the equation of the line, we can find b = (MINY-STEM)-MX MINX.The heights for all the other stems can then be calculated. For each note, put the X and Ycoordinates in NOTEX and NOTEY. The height for this stem is then HEIGHT =NOTEY-MxNOTEX-b.

Although this requires much morecomputation time on the computer, itdoes produce an aesthetically pleas-ing symbol and allows the user tofine-tune the form of the symbol bysimply moving a few of the interpola-tion points.

Other Points

Now that the basic design of theeditor has been presented, I willdiscuss some of the finer points of thedesign.

Patterns and Sequences

Although the input format issatisfactory for most music, the use ofthe current template becomes taxing,if not impossible, when creating ascore of complex music. There is nofacility that allows the user to inputcomplex rhythms. In order to providethis ability, the concept of a pattern

112 May 1980 © BYTE Publications Inc

TODAY MAY BE THE BEST TIMETO MAKE TOUR CAREER MOVE

But first make sure your new employer measures up.

With all of those prospective employers trying to attract your engineering skills, now is the best time to lookbeyond "just a job" and consider your career. Your real objective is to find the perfect combination—challenge,satisfaction, security, and reward. To assist you, we've prepared a checklist of points to consider when you'reevaluating a new employment possibility. It's a good way to compare the companies seeking your expertise.

Career Opportunity Checklist for Engineers

INDUSTRY GROWTH AND STABILITY

No one wants to be "phased out," so check for security: YES ? NO

Is the company part of an industry that's vital, growing, dynamic? ....ODDWill the growth continue throughout the 1980s and beyond? □ □ □

COMPANY HISTORY AND REPUTATION

You can tell a lot about a firm by its track record:

Is the company recognized and respected in the industry? □ □ □

Have sales and profits increased at a steady rate? □ D □

Is it known for its technological innovations? D □ □

Are its employees motivated and well rewarded? □ □ □

Does the company seek technological employees on a permanent,

ongoing basis? □ D □

WORKING CONDITIONS AND ENVIRONMENT

Look for good people, team spirit, and top-notch facilities:

Is the atmosphere one of loyalty, pride, and achievement? □ □ □

Do employees welcome the challenge of difficult assignments? □ □ D

Are creativity and independent thinking encouraged? □ □ □

Are the company's engineering goals clear-cut and attainable? D □ □

THE COMPANY LOCATION

Relocation is a big professional and personal commitment.

Is the company located in an existing or emerging electronics center? ,.D DOAre there major universities and other technological resources nearby? ,DDD

Will the company assist me in relocating? □ □ □

Can I provide my family a comfortable lifestyle in this area? □□□

Are there cultural and entertainment opportunities? □ D □

Is there a variety of recreational and leisuretime activities? □ □ □

Are the climate and surroundings pleasant? □ □ □

PERSONAL AND PROFESSIONAL GROWTHJob satisfaction means more than just a paycheck:

Does the company give full recognition to the engineering role? □ □ □

Will I be working and interacting with other talented professionals

in my field? □□□

Will my accomplishments be acknowledged, appreciated, rewarded? . . □ □ □

Will I be encouraged to seek more challenge and responsibility? □ □ □

Will the company pay for advanced training in technology

and management? □ □ □

Can I pursue my own career goals within the company framework? . . . □ □ D

THE LONG RANGE PICTURE

Where will you be professionally in 5 years?.. .in 10 years?

Are there plenty of opportunities for rapid advancement within

the company? □ □ □

Does the company encourage engineers to assume positions of authority? □ □ □Will I be allowed to move into those engineering areas that interest

me most? D □ □

Can I choose my own career path —into technological leadership or

executive management? □ □ □

One Company to Evaluate

At Racal-Mllgo, we're looking for capable communica-tions hardware and software people to join our engi-neering team. Our success has created needs at everylevel, from entry to top management. We have a lot tooffer you.

The mainstream of our business is data communica-tions—where today's action is. We're a pioneer, and arecognized leader in the field. Our state-of-the-artproduct lines include modems, multiplexers, data en-cryption, and systems for sophisticated network con-trol and performance assessment.We're proud of our growth— $64 million in sales twoyears ago, *80 million last year, and over $100 millionthis year—and we're still growing. Applied research andtechnology keep us on the leading edge in data commu-nications; our engineers face some of the industry'smost challenging (and rewarding) responsibilities.

Racal-Milgo is a great place to work. We encourage ourtechnical people to think creatively, to turn their in-novative ideas into successful products—in an atmo-sphere of friendly, professional teamwork. We providethem with one of the nation's most advanced engi-neering facilities. Our salaries and benefit programsare among the best in the business.We're located in suburban South Florida, one of thegrowing new electronics centers in the sunbelt. It's aninternational area, gateway to Latin America, blessedwith a pleasant climate year-round. There are excellentcultural and entertainment opportunities, plus swim-ming, diving, boating, sport fishing, golf, tennis, andall the other benefits of a cosmopolitan resort. There'sa wide choice of employee clubs to introduce you andyour family to new activities. And if you're interestedin furthering your professional or business relatededucation, we'll pay for your coursework at any of themajor universities nearby.

At Racal-Milgo, we're experiencing dynamic growth,and we need good people at all levels. The workingconditions are excellent...advancement and rewardscome fast...and our new two-track career programlets you decide whether to rise to the top on the tech-nical side or to move into management. (Our presi-dent and board chairman are both EE's.)

We're looking for the best. If you aretoo, let's get together. I hope to per-sonally welcome you aboard. Sendme your resume today; no letter re-quired. You'll receive a prompt reply.

Racal-Milgo

Racal-Milgo, Inc.

8600 N.W. 41st Street Miami, Ft 33166

Ed Hilpert

Vice-President. Engineering

Circle 66 on inquiry card.

BYTE May 1980 113

HALF

j

QUARTER

J

EIGHTH

SIXTEENTH

THIRTY-SECOND

TRIPLET3

SEXTUPLET

6

DOTTED HALF

J.

DOTTEDQUARTER

J.

DOTTED EIGHTH

J)

DOTTEDSIXTEENTH

DOTTEDTHIRTY-SECOND

DOTTED TRIPLET3

DOTTED SEXTUPLET

^

6

WHOLE

o

SIXTY-FOURTH

*

5TH

7TH

9TH

IOTH

1 1 TH

SET

END

DISPLAY

I2TH

I3TH

I4TH

I5TH

PAT

1

2

3

4

5

6

SEQ

1

2

3

4

5

G

Figure 9: Extensions to the musical template for more advanced editing.

of rhythm is created. Here the usercan establish any rhythmic patternwith a code number. When this codenumber is touched on the template,the interface program organizes thenotes which are entered after itaccording to that rhythm. Thetemplate must now have more fieldson it to accommodate this ability,and the interface program must be ex-panded to perform these computa-tions. The extensions to the templateare shown in figure 9. In order tocreate a rhythmic pattern the usermust issue the following commands:

1. Push SET and PAT. This informsthe interface program that a pat-tern is to be created.

2. Push a number on the PAT row.This will be the number of thepattern, and any existing patternwith this number is overwritten.

3. Push the series of note valueswhich determines the pattern.

4. Push END. This signifies the endof the pattern.

To use the pattern the user issues thefollowing commands:

1. Push the number of the pattern.

2. Push the pen onto the correctpitch positions on the staff,preceding them with any attachedsymbols such as sharps, dots,slurs, etc. Note that the order ofthe notes and symbols is now im-portant, but the X locations onthe staff are immaterial.

The end of the pattern occurs whenthe number of notes of the pattern ispushed onto the screen. If more notesare entered before another patternnumber is pushed, the interface pro-gram issues a warning to the usersignifying that the pattern is ended. Ifan insufficient number of notes isentered before another command isissued, the user is warned and the in-complete input is discarded.

A sequence, as used here, is simplya series of patterns. Suppose that se-quence 1 consists of the patterns 2, 5,1. The use of sequence 1 will cause thenotes pressed to follow the rhythm ofpattern 2. When all of its notes areused up, it will follow the rhythm ofpattern 5, and when that is finished, itwill follow pattern 1. Setting a se-quence is similar to the setting of a

pattern. The steps are:

1. Push SET and SEQ.

2. Push a number in the SEQ row.This is the sequence number.

3. Push a series of numbers in thePAT or SEQ row.

4. Push END.

Sequences can cross over measuresand can consist of other sequences.To clarify these concepts, input themusic in figure 7, using patterns andsequences. There are many ways toinput that section of score. Break upthe rhythms into their smallest com-ponents and then form sequencesfrom them. Thus, three patterns aredefined first: one consisting of aquarter note only, the other of twoeighth notes, and the last of four six-teenth notes. The following com-mands do this:

1. Push SET, PAT, and 1.

2. Push QUARTER.

3. Push END.

4. Push SET, PAT, and 2.

5. Push EIGHTH twice.

6. Push END.

114 May 1980 © BYTE Publications Inc

Circle 67 on inquiry card.

$10000.00 + PLUS $

SPONSORED BY THE MAKERS OF THE

BASIC SOFTWARE LIBRARY

NOW • 10 * Volumes and Growing

And unlike others we are giving a portion in CASH that you Don't have to spend with us.

In addition to the $10,000 Give Away we are going to celebrate July 4th by giving a SpecialBonus to purchasers of an entire set of the Basic Software Library on a single order.

* SPECIAL BONUS • 15% discounts on single purchase of full set by July 4th, 1980

We have over 100,000 in circulation since 1975 and we are still around and That's more than Anyone else can say. Weused to sell hundreds of programs individually, the programs in Volume X were sold for several years at over $10,000,in Volume III for over $6,000 but a few years ago we decided to promote software to the mass public and it was aninstant success. We are still several years ahead of our time in our marketing concepts as well as our products and weare going to be making another major change in the market. We are going to offer our programs in cassette form. NOTjust one of two programs like everybody else. But a book full of programs for just $9.95.

For Homeowners, Businessmen, Engineers, Hobbyists, Doctors, Lawyers, Men and Women

Vol.) $24.Business &PersonalBookkeepingPrograms

Bond

Building

Compound

Cyclic

Decision 1

Decision 2

Depreciation

Efficient

Flow

Installment

Interest

Investments

Mortgage

Optimize

Order

Pert Tree

Rate

Return 1

Return 2

Schedule 1

Games &Pictures

95

Animals Four

Astronaut

Bagel

Bio Cycle

Cannons

Checkers

Craps

Dogfight

Golf

Judy

Line Up

Pony

Roulette

Sky Diver

Tank

Teach Me

A. Newman

J.F.K.

Linus

Ms. Santa

Nixon

Noel Noel

Nude

Peace

Policeman

Santa's Sleigh

Snoopy

Virgin

Vol. II $24BinomialChi-Sq.Coeff.

Confidence 1Confidence 2CorrelationsCurveDifferencesDual PlotExp-DistriLeast SquaresPairedPlotPlotpts

Polynomial FitRegressionStat 1Stat 2

T-DistnbutionUnpairedVariance 1Variance 2XY.

APPENDIXA

95

Beam

Conv.

Filter

Fit

Integration 1

Integration 2

Intensity

Lola

Macro

Max. Min.

Navaid

Optical

Planet

PSD

Rand 1

Rand 2

Solve

Sphere Trian

Stars

Track

Triangle

Variable

Vector

Vol. Ill

Vol. IV

Vol.V

Vol. VIM

Vol. IX

Vol. X

$39.95

$9.95

$9.95

$19.95

$19.95

$69.95

Billing

Bingo

Andy Cap

1040-Tax

Auto

Intro.

Inventory

Bonds

Baseball

Cypher

A/R

Payroll

Bull

Compare

Balance

Hurrtrac

A/P

Risk

Enterprise

Confid 10

ID

Mer Inv

Sched..:a2

Football

Descrip

Checkbook

Lorana

Check

Shipping

Funds 1

Differ

Map

Assets

Slocks

Funds 2

Engine

lnstol78

Navigate

Payroll

Switch

Go-Moku

Fourier

Omega

BalSh

Jack

Horse

Deprec 2

Patterns

P/L

Vol. VI

Life

Integers

Radar

Year End

$49.95

Loans

Logic

APPENDIX C

RDF

Data Base

Mini-LedgerPayrollA/Ft

InventoryPeprec.

MazesPokerPopulProfits

PlayboyPrimesProbalQuadrac

Favorites

Tax UpBasic St.

Volume Ill-

-Partl-

-Billing Inv. Pyrl.

Qubic

Red Baron

Volume VII

—Parti -

-Chess

Ledger

RatesRetireSavings

Regression 2Road RunnerRoulette

—available on TRS-80 level IIcompatible cassette $9.95

Vol. VII

SBATic-Tac-Toe

SantaStat 10

Add $1.00 per tape Post./Handling

$39.95

Stat 11

Volume VI -

— Disk programs are

ChessMedbil

SteelTopVaryXmas

compatible with TRS-80 disk basic

Wdproc

The disk progwritten in (CP

amsin Volumes VI. VII and X are

Utility

'MIMBasi

; and Disk Extended

Microsoft Basic. Other programs written in 8K

APPENDIX B

Basic.

SELECTED PROGRAMS AVAILABLE ON CASSETTE

Add $1.50 per volume handling, all domestic shipments sent UPS. except APOand P.O. Box which go parcel post. Foreign orders add $6.00/volume for airshipment and make payable in U.S. dollars only.

AVAILABLE AT MOST COMPUTER STORES

Master Charge and Bank Americard accepted.

Our Software is copyrighted and may not be reproduced or sold.

Unlike others we have NOT raised our prices in five years

No Purchase Necessary, to enter send name& addressona3x 5card.You are automatically entered everytime you make a purchase from us.

Void whom prohibited by law.

KEMCO, LTD.

P.O. Drawer 2208L Petersburg, VA 23803

24 Hour HOT LINE 800-528-6050 extIn Arizona call 800-352-0458

1184

Na12:

GourmetGoodies

Software lor most popular 8080/280' computer disk systems including NORTH STAR, iCOM, M1CROPOL1S, DYNABYTE DS8/2

S DB8/4, EXIDY SORCERER, SD SYSTEMS, ALT AIR, VECTOR IWZ, MECA, 8" IBM, HEATH H17 & H89, HELIOS, /^^H^"^' / f^/lk™

IMSAI VDP42 & 44, REX, NYLAC, INTERTEC SUPER-BRAIN, VISTA V80 and V200, TRS-80* MODEL I and MODEL II, ALTOS, <-' Unj&o™: UA^UOHIO SCIENTIFIC, OIGI-LOG, KONTRON PS180, IMS 5000 DISKETTE formats and CSSN BACKUP cartridge tapes. CfW^g-

jtrrrrtd

A surcrinrgu ol S25 *

i added lor sol

CP/M VERSION 2 FOR TRS-80 MODEL II NOW AVAILABLE

All Lifeboat programs require CP/M, unless otherwise stated.

Hllti /ManualManual/ Alone

-Ith/M.itinual/ All

0 CP/M' FLOPPY DISK OPERATING SYSTEM - DigitalResearch's operating system configured (or manypopular micro-computers and disk systems:System Version Price

North Star Single Density 1.4 145/25 V

North Star Double Density 1.4 145/25

North Star Double/Quad 2.x 170/25

iCOM Micro-Disk 2411 1.4 145/25

iCOM 3712 1.4 170/25 v*

iCOM 3812 1.4... . 170/25 '

Mils 3202/Altair 8800 1.4 145/25

Heath H8 + H17 1.4. .. .145/25®

Heath H89 1.4. .. .145/25®

TRS-80 Mode! I 1.4 145/25 ®

THS-80 Model II 2.x... . 170/25

Processor Technology Helios II .. 1.4... .145/25

Cromemco System 3 1.4.... 145/25

Intel MDS Single Density 1.4 145/25

Intel MDS Single Density 2.x 170/25

Intel MDS 800 Double Density .. 2.x 200/25

Intel MDS 230 Double Density 2.x 200/25

Micropolis Mod I 1.4 145/25 v

Micropolis Mod It 1.4 145/25 V

The following configurations are scheduled for re-lease during the first hall of 1980:North Star Double/Quad + Corvus 2.x.. . .250/25

North Star Horizon HD-1 2.x 250/25

Ohio Scientilic C3 2.x 200/25

Ohio Scientific C3-B 2.x 250/25

Ohio Scientific C3-C 2.x 250/25

Micropolis Mod M 2.x 200/25

Mostek MDX STD Bus System . . . .2.x 350/25 **

iCOM 3812 2.x... .225/25 '

iCOM 4511/Pertec D3000 2.x 375/25 *+

TRS-80 Model II + Corvus 2.x 250/25

Software consists o! the operating system, text edi-tor, assembler, debugger and other util ties lor tilemanagement and system maintenance. Complete setol Digital Research's documentation and additionalimplementation notes included. Systems marked 'and " include firmware on 2708 and 2715. Systems

MICROSOFT

in this catalog. Systems marked v have minor variantsavailable to suit console interlace ol system. Call orwrite lor lull list ol options.

P MP/M" - Intel MDS single density only (Documenta-tion includes CP/M 2.0 manuals) $300/550

n ZB0 DEVELOPMENT PACKAGE-Consisls of: [1) disk(8, file line editor, with global inter and intra-line facili-ties; (2) Z80 relocating assembler, Zilog/Mostek mne-monics, conditional assembly and cross referencetable capabilities; (3) linking loader producing abso-lute Intel hex disk file S95/$Z0

□ 2DT — Z80 Monitor Debugger to break and examine(5) registers with standard Zilog/Mostek mnemonic dis- /.„/assembly displays. S35 when ordered wifh Z80 pevel- wr,]

iy

opment Package S50/$10 yf/fl

■tfr\

hardware floating point. Version 3 includes

, Enumeration and Record data types. Manual explains

G XASM-68-Non-macro cross-assembler with nested ■$$ . BAS,C lo PASCAL conversion. Source for the run-

tj«Vr\7 lirne PackaSe requires Digital Research's MAC. Re<

conditionals and full range of pseudo operations. As-sembles from standard Motorola MC6800 mnemonicsto Intel hex S200/S25

ri XASM-65-As XASM-68 for MOS Technology MCS-6500 series mnemonics $200/325

□ DISTEL-Disk based disassembler lo Intel 8080 orTDL/Xitan Z80 source code, listing and cross refer-ence files, Intel or TDL/Xitan pseudo ops optional.Runs on 8080 $65/510

□ DISILOG-As DISTEL to Zilog/Mostek mnemonic® files. Runs on Z80 only $65/310

D SMAL/80 Structured Macro Assembler Language —(x) Package of powerful general purpose text macroprocessor and SMAL structured language compiler.SMAL is an assembler language with IF-THEN-ELSE,LOOP-REPEAT-WHILE, DO-ENO, BEGIN-END con-structs $75/$15

□ liny C — Interactive interpretive system for teaching© structured programming techniques. Manual includes

full source listings $105/$40

□ BDS C COMPILER-Supports most features of lan-® guage, including Structures, Arrays. Pointers, recur-® sive function evaluation, overlays. Includes linking

loader, library manager, and library containing gen-eral purpose, file I/O, and floating point functions.Lacks initializers, statics, floats and longs. Docu-/ mentation includes "The C PROGRAMMING LAN-GUAGE'' by Kernighan and Ritchie $125/$20

LI WHITESMITHS C COMPILER - The ultimate in sys-© terns software tools. Produces faster code than agj pseudo-code Pascal with more extensive facilities.Conforms to the full UNIX' Version 7 C language, de-scribed by Kernighan and Ritchie, and makes avail-able over 75 functions for performing I/O, stringmanipulation and storage allocation. Linkable toMicrosoft REL files. Requires 60K CP/M $630/530

~7ii£&£issC0WMs£&ue&d /

,*/2-

£"TX^ v*»

with /Mi

Manual/ Ah

n BASIC-80-Disk Extended BASIC, ANSI compatible®(x) with long variable names, WHILE/WEND, chaining,(S){x) variable length file records S325/$25

□ BASIC COMPILER - Language compatible with© BASIC-80 and 3-10 times faster execution. Produces(a standard Microsoft relocatable binary output. In-

eludes MACRO-80. Also linkable to FORTRAN-80 orCOBOL-80 code modules $350/525

□ FORTRAN-BO - ANSI 66 (except lor COMPLEX) plus© many extensions. Includes relocatable object com-® pller, linking loader, library with manager. Also in-cludes MACRO-80 (see below) $425/525

□ COBOL-80- Level 1 ANSI '74 standard COBOL plus© most of Level 2. Full sequential, relative, and in-rO) dexed lile support with variable file names. STRING,

UNSTRING, COMPUTE, VARYING/UNTIL, EXTEND,CALL, COPY, SEARCH, 3-dimensional arrays, com-pound and abbreviated conditions, nested IF. Power-ful interactive screen-handling extensions. Includescompatible assembler, linking loader, and relocat-able library manager as described under MACRO-BO $700/525

□ MACRO-80 -8080/Z80 Macro Assembler. Intel and© Zilog mnemonics supported. Relocatable linkable(Oj output. Loader, Library Manager and Cross Refer-

ence List utilities included $149/$15

□ XMACRO-B6 - 8086 cross assembler. All Macro and© utility features of MACRO-80 package. Mnemonics

slightly modified Irom Intel ASM86. Compatibility datasheet available $275/$25

□ EDIT-B0 - Very (as! random access text editor for text© with or without line numbers. Global and intra-line

commands supported. File compare utility included. $89/515

□ PASCAL/M* —Compiler generates P code from ex-

® tended language, implementation of standard PAS-

marked + include 5440 media charge. Systems 1 ',y- CAL. Supports overlay structure through additional

marked % require the special ® versions ol software • . I procedure calls and the SEGMENT procedure type.

fn iiklfl AAtrtfnf, OllalAM* MaA.r.-J., !.«.. .1... ! I- St I i 1V" D*s-

Jftt Provides convenient siring handling capability7 Ihe added variable type STRING. Untyped files allowmemory image I/O. Requires 56K CP/M $150/320

□ PASCAL/Z - ZS0 native code PASCAL compiler. Pro-Q duces optimized, ROMable re-entrant code. All inter-facing to CP/M is through the support library. Thepackage includes compiler, Microsoft Compatible re-locating assembler and linker, and source for alllibrary modules. Variant records, strings and directI/O are supported. Requires 56K CP/M and Z80 CPU. $395/525

□ PASCAL/MT - Subset of standard PASCAL. Gener-® atos ROMable 8080 machine code. Symbolic debug-(x) ger included. Supports interrupt procedures, CP/M

file I/O and assembly language interface, Real vari-ables can be BCD, software floating point, or AMD

f quires 32K . $250/530

["I ALGOL-60 —Powerful block-structured language com-piler featuring economical run-lime dynamic alloca-tion of memory. Very compact (24K total RAM) sys-tem implementing almost all Algol 60 report featuresplus many powerlul extensions including siring han-dling direct disk address I/O etc. Requires Z80CPU $199/520

□ CBASIC-2 Disk Extended BASIC - Non-interactive(Si BASIC with pseudo-code compiler and run-time in-terpreter. Supports full lile control, chaining, inleqerand extended precision variables, etc $120/315

MICRO FOCUS

□ STANDARD CIS COBOL - ANSI '74 COBOL stand-© ard compiler fully validated by U.S. Navy tests to

ANSI level 1. Supports many features to level 2 in-cluding dynamic loading of COBOL modules and afull'ISAM file facility. Also, program segmentation,interactive debug and powerful interactive extensionsto support protected and unprotected CRT screenformatting from COBOL programs used with anydumb terminal $850/350

□ FORMS 2-CRT screen editor. Output is COBOL data© descriptions for copying into CIS COBOL programs.

Automatically creates a query and update program ofindexed liles using CRT protected and unprotectedscreen formats. No programming experience needed.Output program directly compiled by CIS COBOL(standard) $200/$20

EIDOS SYSTEMS

LI KISS - Keyed Index Sequential Search Offers com-© plete Multi-Keyed Index Sequential and Direct Ac-cess lile management. Includes built-in utility func-tions for 16 or 32 bit arithmetic, string/integer conver-sion and string compare. Delivered as a relocatablelinkable module in Microsoft format lor use withFORTRAN-80 or COBOL-80, etc S335/S23

□ KBASIC-Microsoft Disk Extended BASIC with all

© KISS facilities, integrated by implementation of nine

additional commands in language. Package includes

KISS. REL as described above, and a sample mail

list program $585/345

To licensed users of Microsoft BASIC-80 (MBASIC) $435/545

] XYBASIC Interactive Process Control BASIC - Fulldisk BASIC features plus unique commands to han-dle bytes, rotate and shift, and lo tost and set bits.Available In Integer, Extended and ROMable versions.

Integer Disk or Integer ROMable $295/$25

Extended Disk or Extended ROMable S395/S25

G BASIC UTILITY DISK - Consists of: (1) CRUNCH-14® — Compacting utility to reduce Ihe size and increasethe speed ol programs in Microsoft BASIC and TRS-80 BASIC. (2) DPFUN - Double precision subroutinesfor compuiing nineteen transcendenial lunctions in-cluding square root, natural log, log base 10, sin, arcsin, hyperbolic sin, hyperbolic arc sin, etc. Furnishedin source on diskette and documentaiion .. .$50/535

□ STRING/80 - Character string handling plus routines0 for direct CP/M BDOS calls from FORTRAN and other

compatible Microsoft languages. Tho utility librarycontains routines that enable programs to chain toa COM file, retrieve command lino parameters, andsearch file directories with full wild card facilities.Supplied as linkable modules in Microsoft format.

S95/S20

STRING/ao source code available separately S295/n.a.

□ THE STRING BIT - FORTRAN character siring han-dling. Routines to find, fill, pack, move, separate,concatenate and compare character strings. Thispackage completely eliminates the problems asso-ciated with character string handling in FORTRAN.Supplied wilh source 565/515

□ VSORT — Versatile sort/merge system for lixed length® records with fixed or variable length fields, VSORT

j can be used as a stand-alone package or loaded and

,/\JJ called as a subroutine from CBASIC-2. When used as

rvu 7a subroutine, VSORT maximizes the use of buffer

I' ' space by saving the TPA on disk and restoring it on

/ completion of sorting. Records may be up to 255

bytes long with a maximum of 5 fields. Upper/lower

case translation and numeric fields supported.

$175/520

□ CPM/374X - Has full range of functions to create orre-name an IBM 3741 volume, display directory infor-mation and edil the dala set contents. Provides lullfile transfer lacilities between 3741 volume data setsand CP/M files 5195/510

[J BSTAM — Utility to link one computer to another also® equipped with BSTAM. Allows file translers at fulldala speed (no conversion fo hex), with CRC blockcontrol check for very reliable error detection andautomatic retry. We use it! It's groat! Full wildcardexpansion to send *.COM, etc. 9600 baud with wire.300 baud with phone connection. Both ends needone. Standard and ;m; versions can talk to one another. $150/55

] WHATSIT?* Interactive data-base system using as-sociative tags to retrieve information by subject.Hashing and random access used for fast response.Requires CBASIC-2 $175/$25

] SELECTOR II1-C2 - Dala Base Processor to createand maintain multl Key data bases. Prints formattedsorted reports with numerical summaries or mailinglabels. Comes with sample applications, includingSales Activity, Inventory, Payables, Receivables,Check Register, and Client/Patient Appointments, etc.Requires CBASIC-2. Supplied in source . . .$295/320GLECTOR-General Ledger option to SELECTORIII-C2. Interactive system provides for customizedCOA. Unique chart of transaction types insure properdouble entry bookkeeping. Generates balance sheets,P&L statements and journals. Two year record allowsfor statement ol changes in financial position report.Supplied in source. Requires SELECTOR III-C2,CBARIC-2 and 52K system $250/325

CBS — Configurable Business System is a compre-hensive set ol programs for defining custom cfatafiles and application systems without using program-ming language such as BASIC, FORTRAN, etc. Mul-, tiple key fields lor each dala file are supported. Set-upprogram customizes system to user's CRT and printer.Provides fast and easy interactive dala entry andretrieval wilh Ironspction processing. Report genera-tor program does complex calculations with storedand derived dala, record selection wilh multiple cri-teria, and custom lormats. Sample inventory and mail-ing list systems included. No support language re-quired $295/325

$

d

.lions subject lo change without notice.

MICRO DATA EASE SYSTEMS

□ HDBS- Hierarchical Data Base System. CODASYLoriented with FILEs. SETs, RECORDS and ITEMSwhich are all user defined. ADD, DELETE, UPDATE.SEARCH, and TRAVERSE commands supported. SETordering is sorted, FIFO, LIFO, next or prior. One tomany set relationship supported. Read/Write protec-tion at the FILE level, Supports FILEs which extendover multiple floppy or hard disk devices.

□ MDBS- Micro Dala Base System. Full network database with all features ol HDBS plus multi-level Read/Write protection for FILE, SET, RECORD and ITEM.Explicit representation of one to one, one to many,many to many, and many to one SET relationships.Supports multiple owner and multiple record typeswithin SETs. HDBS files are fully compatible.

□ MDBS-DRS - MDBS with Dynamic Restructuring Sys-tem option which allows altering MDBS data baseswhen new ITEMs. RECORDS, or SETs are neededwithout changing existing dafa.

HDBS-Z60 version $250/540

MDBS-Z80 version 5750/540

MDBS-DRS-Z80 version $850/S5O

8080 Version available a! S75 extra

When ordering, specify one of thelanguages listed below.

M ,^HDBS and MDBS manuals purchased alone comei / ' without specilic language interface manuals. Manualsf are available for the following Microsoft languages;1) MBASIC 4.51. 2) BASIC-80. 5.0, 3) CompiledBASIC-80 or FORTRAN-80, 4) COBOL-B0, 5) MACRO-80 5NA/S10

,\M^

LAMICROPRO l[j SUPER-SORT I - Sorf. merge, extract utility as abso-© lute executable program or linkable module in Micro-soft format. Sorts lixed or variable records wilh dalain binary. BCD, Packed Decimal, EBCDIC. ASCII,floating & fixed point, exponential, field justified, etc.Even variable number of fields per record! .S225/525i_i SUPER-SORT II - Above available as absolute pro-© gram only $175/525

Tl SUPER-SORT III-AS II without SELECT/EXCLUDE

© S125/S25

P WORD-STAR — Menu driven visual word processing© system for use wilh standard terminals. Text format-ting performed on screen. Facilities for text paginate,page number, justify, center and underscore. Usercan print one document while simultaneously editinga second. Edil lacilities include global search andreplace. Read/Write to other text files, block move,etc. Requires CRT terminal with addressable cursor

positioning 5445/540

" WORD-STAR Customization Notes -For sophisticatedusers who do nol have one of the many standardterminal or printer configurations in Ihe distribution

version of WORD-STAR NA/S95

□ WORD-MASTER Text Editor-In one mode hassuper-© set of CP/M's ED commands including global search-ing and replacing, forwards and backwards in fite invideo mode, provides full screen editor for users withserial addressable-cursor terminal 3125/325

Oat Associates

FTWARESUPER-MARKET

%

Lifeboat Associates, 2248 Broadway, N.Y., n.y. 10024 (212) 580-0082 Telex: 220501

5/s-

| POLYVUE-80 - Full screen editor (or any CRT with

(Mi XY cursor positioning. Includes vertical and horizon-tal scrolling, interacllvo search and replace, auto-matic text wrap around for word processing, opera-tions lor manipulating blocks ot text, and compre-

hensive 70 page manual S135/S1S

POLYTEXT/80 - Text formatter for word processing

@ applications. Juslifies and paginates source text lilos.Will generate form letters with custom fields andconditional processing. Support for Daisy Wheelprinters Includes variable pitch justiliC3lion and mo-tion optimization $85/515

TEXTWRITER IK - Text formatter to justify and pagi-

* nale letters and other documents, Special featuresinclude insertion of text during execution from otherdisk files or console, permitting recipe documentsto be riBfllairt from linked fragments on other files.Has facilities for sorted index, table ot contents andfootnote insertions. Ideal for contracts, manuals, etc.Now compatible with Electric Pencil' prepared files. $125/820

□ APARTMENT MANAGEMENT SYSTEM - Financial© management system for receipts and security de-(W> poslls of apartment projects. Captures dala on va-t cancies. revenues, etc. for annual trend analysis.

Daily report shows late rents, vacancy notices, va-cancies, income lost through vacancies, etc. RequiresCBASIC-2. Supplied in source S590/S35

□ CASH REGISTER - Maintains files on daily sales.© Files dala by sales person and ilom. Tracks sales,<u> over-rings, refunds, payouts and total net deposits.

J Requires CBASIC-2. Supplied in source . . .S590/S35

□ POSTMASTER - A comprehensive package for mail

®» list maintenance that is completely menu driven.

Features include keyed record exlraclion and label

l(r JjProduc,ion- A 1°"" leXer program is included which

J (^provides neat letters on single sheet or continu-

y,

\3A5/c JkfafACGts.'

PEACHTBEE SOFTWARE *

PI GENERAL LEDGER - Records details of all financial

© transactions. Generates a balance sheet and an in-t come statement. Flexible and adaplable design forboth small businesses and firms perlorming clionlwrifeup services. Produces reports as follows: TrialBalance. Transaction Registers, Balance Sheet. PriorYear Comparative Balance Sheet, Income Statement.Prior Year Comparative Income Statement and De-partment Income Stalemenls. Interactive with oilierPEACHTREE accounting packages. Supplied In

source code lor Microsoft BASIC $9907$30

n ACCOUNTS PAYABLE-Tracks current and aged© payables and incorporates a check writing feature.t Maintains a complete vendor file with information onpurchase orders and discount terms as well as activeaccount slalus. Produces reports as follows: OpenVoucher Report, Accounts Payable Aging Report andCash Requirements Provides Input to PEACHTREEGeneral Lecger. Supplied in source code for Micro-soft. BASIC S990/S30

D ACCOUNTS RECEIVABLE - Generates invoice regis-© ler and complete monihly stalemenls. Tracks currentt and aged receivables. Maintains customer file includ-ing credit inlormalion and account status. The cur-rent status of any customer account is instantly avail-able. Produces reports as follows: Aged AccountsReceivable, Invoice Register. Paymenl and Adjust-ment Register and Customer Account Status Report.Provides input to PEACHTREE General Ledger. Sup-plied in source code lor Microsoft BASIC - .S990/S30

□ PAYROLL - Prepares payroll for hourly, salaried and© commissioned employees. Generates monthly, quar-1 lerly and annual returns. Prepares employee W-2's.

Includes tables tor federal withholding and FICA aswell as withholding for all 50 slates plus up to 20cities from pre-compuled or user generated tables.Will print checks. Payroll Register, Monthly Summaryand Unemployment Tax Report. Provides input toPEACHTREE General Ledger. Supplied in sourcecode for Microsoft BASIC S990/S30

□ INVENTORY - Maintains detailed information on0 each inventory item including part number, descrip-

1 tion, unit of measure, vendor and reorder data, itemactivity and complete Information on current Itemcosts, pricing and sales. Produces reports as follows:Physical Inventory Worksheet, Inventory Price List,Departmental Summary Report, Inventory Status Re-port, The Reorder Report and the Period-to-Date andYear-to-Datc reports. Supplied in source code lorMicrosoft BASIC $1,1SO/$30

□ MAILING ADDRESS - Keeps track of name and ad-(Ti dress inlormalion and allows the selective printing of\ this information in the form of mailing lists or ad-dress labels. Allows the user lo tailor the system tohis own particular requirements. User-defined tor-mat and print-out system uses a special format filewhich tells programs how to print the mailing list oraddress labels. Standard lormat files are Includedwith system. Automatic sorting of data uses indexeddie management routines which allow the name andaddress information to be sequentially retrieved andprinted without file soiling. Supplied in source codelor Microsofl BASIC S790/S30

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□ ACCOUNTS PAYABLE - Maintains vendor list and© chock regislcr. Performs cash How analysis. Flexible(fij — writes checks to specific vendor lor certain in-

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INVENTORY SYSTEM - Captures slock levels, costs.'.ii sources, sales, ages, turnover, markup, etc. Trans-& action intormahon may bo entered lor reporting byt salesman, typo ol sale, date o( sale, etc. Reporlsavailable both lor accounting and decision making.Requires CBASIC-2. Supplied in source . .$590/535JOB COSTING - Designed for general contractors,© To be used interactively with other GRAHAM-DORIAN§ accounting packages tor tracking and analysing ex-t penses User establishes customized cost categoriesand job phases. Permits comparison of actual versusestimated costs Automatically updates GRAHAM-DORIAN General Ledger or runs as stand alone sys-tem. Requires CBASIC-2. Supplied in source S995/S35

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[J INVENTORY CONTROL SYSTEM - Performs controlt lunctions of adding and depleting slock items, add-ing now items and delethg old items. Tracks quantityol items on hand, on order and back-ordered. Op-tional hard copy audit trail is available. Reporls in-clude Master Hem List. Slock Activity. Stock Valua-tion and Re-order Lisl. Requires CBASIC-2 $1250/525

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7. Push SET, PAT, and 3.

8. Push SIXTEENTH four times.

9. Push END.

Note that there are now four se-quences that can be defined. They arelabelled on the score. I will create thecommands for the first one only,since the others are similar:

1. Push SET, SEQ, and 1.

2. Push 3,1,2,1,2,1,1,1 onrow.

3. Push END.

the PAT

The other sequences consist of:

#2 -3,1,3,1,1,2,2,1

#3 -3,1,3,1

#4 -2,2,2,2,2,1,1,1

The different ways of ordering se-quences and patterns are numerous.The above score in particular couldhave been entered in several ways.

Using a scheme like this, any scoreof music can be entered into theeditor. Other schemes could be de-vised to tailor the input form to thetype of music being edited. The onlychanges to the program, however,would occur in the input-interfaceprogram; the main part of the editorwould remain unchanged.

Symbols That Cross OverMeasures

I have not yet approached theproblem of symbols that cross overmeasures and, thus, over lines andpages. Nor have I discussed the place-ment of nested slurs or ties and howto draw them on the screen. Theseproblems are complex; their solutionslie in keeping pointers in the characterarray to the locations where the sym-bol begins and ends. Any changes tothese measures, such as deletion,must also change these pointers — forexample, we do not have a beginningof a crescendo with no end. Thusthese pointers must again be doubly-linked. Drawing the correct arcs forslurs and ties, presents a problembecause they can be separated by longdistances. A routine must be calledwhen the screen locations are knownto fit a curve through these points.

Reformatting

After editing a page, the format ofthe pages from then on is usually dif-ferent. If you simply added a

May 1980 © BYTE Publications lnc 117

character in a measure, the pagingwill probably remain the same;however, if you add thirty notes to themeasure, it is much longer, and mightchange the number of measures onthe line and hence the format of thepage. How far this change will carrydepends upon the size of the changeand the scaling factors of themeasures. (If the scaling factors wereall 1.0, then any change to a measurewould cause a complete repaging ofthe score.)

Whenever the user wants to displayor edit the score, a formatting pro-gram must be called to repage thescore. This routine must execute thealgorithms given previously, whichdetermine the beaming groups of themeasures and the measure lengths ofall changed measures. It must thendetermine which measures will go onthe lines. It needs to alter the existingpaging only as far as the change pro-pagates, but there is no way topredict this in advance. Thus a simplechange could cause considerable com-putation.

Conclusion

I hope that the reader has begun to

appreciate the problems involved increating a text editor for music. Whatis the utility of such a program? Toanyone who has ever tried printing ascore of music with india ink, the vir-tues of an editor with hard-copyfacilities are obvious. A number ofuses for the program present them-selves. For example, very often musicwritten in one key needs to bechanged into one of the other keys.This is called transposition. A pro-gram can easily be written whichtakes the contents of the characterarray and performs the transforma-tion.

You might wish to create computermusic and display it on the screen.You could write a music-generationprogram and feed its output to a con-version routine that would convert itsoutput into the format of the editor.If actual sounds were converted intopitches and durations with an elec-tronic device, this could be placed inthe editor, and you could see themusic that was being played. Ifseveral scores by a composer areentered into the program andstatistical analysis is performed onthem to determine the probabilities of

certain patterns of music, the resultscould, in theory, be used to drive amusic-generation program thatwould simulate the composer's style.This same approach could be appliedto music from different historicalperiods, thus enabling the computerto create a classical symphony or atwelve-tone quartet. ■

Editor's note: The data-entrysystem for musical scores de-scribed in this article has a biastoward transcription of scores con-taining a single melodic line. Othertypes of musical scores containelements which are not dealt withhere. For instance, music forkeyboard instruments, such as thepiano, usually contain chords con-sisting of several notes to besounded simultaneously. Thesechords are often written as severalnote heads sharing a single stem. Itwould be difficult at best to workwith such music using this system.Enhancing the system to handlethese elements would be a goodproject for the ambitiousreader. . . . RSS

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118 May 1980 © BYTE Publications Inc

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BYTE May 1980 119

Using the Computer as aMusician's Amanuensis

Part 2: Going from Keyboard to Printed Score

Jef RaskinApple Computer Co

10260 Bandley DrCupertino CA 95014

More Problems with Rhythmand Tempo

The would-be Composer's Aiddesigner plummets into another pileof programming problems when tem-pi change. The beat, sometimes con-stant within a piece, may abruptlyslow down, as may happen in areflective refrain in a blues number,or gradually accelerate, as in a Greekfolk dance. Changes of tempo presentproblems that are worse than theproblems in transcribing rhythmsthat we have already seen.

It is not difficult to see that anabrupt change in tempo cannot bedetected the instant that it happens,but only after a few notes have beenplayed at the new speed, establishing,as musicians say, the new tempo.This brings up the concept thatrhythm does not exist only in relationto the length of individual notes, butexists also in a much larger musicalcontext.

About the Author

Jef Raskin's credentials in music include hisyears as a professional musician and a musicteacher. He is presently the manager of Ad-vanced Systems at Apple Computer Co. Hispersonal music and computer equipment in-cludes a piano, a harpsichord, an organ, aPDP-11, and three Apple 11 computers.

Therefore, a computer (or a humanbeing) cannot notate rhythm in realtime (ie: as it happens). The notatormust wait and accumulate a signifi-cant sample (ie: listen for a while)before making any decision how towrite down what has been heard. Acomputer program that must deter-

A computer (or a humanbeing) cannot notaterhythm in real time.

mine rhythms will most probablyhave to backtrack through the data,perhaps a number of times, beforedeciding how to notate the music.

Much of the fun in listening tomusic comes from anticipation of therhythm; the composer or performercan use rhythmic expectations as abackground against which to intro-duce rhythmic novelties. This issimilar to the use of harmonic andmelodic "surprises" that cannot beassessed until some time after theyhave been heard. The fact that wehear music in a context of expecta-tions built on previous experiencestands as a sentinel, guarding againstthe possibility that there is an easyalgorithm that might "understand"music on a note-by-note basis.

Further Consequencesof Changes of Tempo

A gradual change of tempo is eitheraccelerando (getting faster) or ritar-dando (getting slower). In ritardando(very common at the ends of pieces orsections of pieces), how is the com-puter to tell the difference between agradual lengthening of the writtennote values on one hand, and the useof the word "ritardando" along withan actual constant note length, on theother? This is very easy for a humanto do, but it is very difficult to tell acomputer how we do it.

In many pieces that require thisslowing down, there is no notationfor a ritardando at all. In these cases,the ritardando is inherent in thenature of the music. The conven-tional notation is to write the scoreas if nothing at all happens to thetempo.

This last problem afflicts score-to-performance transforming programsmore than it afflicts programs thattransform performances to scores. Itis one of the symptoms of "soulless"computer performances. The com-puter too often is programmed withonly the notes, but not with thestyle—that part of the music which isindigenous to a culture or time.Without the proper style, music tendsto sound "wooden" or "dead."

120 May 1980 © BYTE Publications Inc

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Someone Tries to Sell theAuthor a "Notating Machine"

An entrepreneur tried to interestme in funding a device he was inthe process of patenting. Accord-ing to him, it would do the"simple" task of transcribing anyrhythm tapped out on its surfaceinto standard musical notation. Itwas to be the size of a hand-heldcalculator.

I asked him the questions that Ihave brought up in this discussion,and it soon became clear that hehad not given the matter even asmuch thought as I have been giv-

ing the problem in this article. Asan answer to the question of accel-erando and ritardando, he sug-gested that the instructions wouldspecify that the user must not slowdown or speed up.

As happens too often in theworld of computing, he was forcedto lean toward a device thatwould—perhaps—write down theeasy rhythms, leaving the difficultones for the user to figure out.Most users, I suspect, would ratherhave a device to write down thedifficult rhythms. The users canfigure out the easy ones without

mechanical aid.

Incidentally, one of the most dif-ficult problems for a beginner tosolve is determining on which beatof a measure a piece begins. Piecesvery often begin in the middle of ameasure. This is also a vexingproblem for anyone who wouldprogram a computer to notaterhythms.

Placing any restrictions notfound in the music itself on theuser seems inherently wrong tome. The system must accommo-date the person, not the other wayaround.

There are many other problemswith rhythm—for example, rubato,where one part momentarily goesfaster or slower than accompanyingparts. Another class of problems arerhythmic complexities such as trip-lets, grace notes (so short that theirtime value is not notated), and othergroups of notes that break the simplerrhythmic patterns.

A triplet is a melodic phrase con-sisting of three notes of equal length,

three quarter notes, for instance.These three quarter notes are playedin the same time interval that twoquarter notes occupy in the normalrhythm of the piece. It is difficult totell what has happened when a fewtriplets are introduced in a piece.When they first occur in a piece, youmay ask yourself (if you are a trainedmusician), "Has the tempo suddenlychanged, or have triplets been intro-duced?" The program will be hard

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put to guess at the difference.

Another problem occurs when verylong notes occur in a piece whichpreviously consisted only of relative-ly short notes. You must decide, forinstance, whether to write them astied shorter notes or as longer noteforms. Of course, they might be writ-ten as the same note-length notationsas the earlier, shorter notes, but witha tempo change!

All of this judgment of tempo mustbe done in the face of the first prob-lem, that the note lengths and incep-tion times are not coming in precise-ly, but with considerable variation.Often, the amount of this variationmay mask tempo or rhythmicchanges. Consider, too, that thepeople who need the Composer's Aidmost are those who may be least pro-ficient at performing upon conven-tional instruments. The designerprobably has a more difficult task tomake the Composer's Aid accuratelyportray the muddled attempts atrhythmic regularity of a beginner,than to make it follow the (probably)more precise playing of a master.

Before leaving the subject ofrhythm, I shall take the liberty to givethe following advice to all would-bedesigners of automatic music-tran-scribing systems. First, build one thathas but one key or button, and get itto determine rhythms correctly. By"correctly " I mean without unrea-sonable limitations. It should be ableto handle any rhythm found in aMozart or a Beatles' melodic line. Ifyou cannot master that, then youcertainly cannot transcribe morecomplex music, which might have asolo melody as a part of a piece.

The problems of rhythm are not

122 May 1980 © BYTE Publicalions Inc

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What programs are available?

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BYTE May 1980 123

AS WRITTEN

^5

(la)

I

AS PLAYED

rit. a tempo

^

I

s

aw

:£s

*

> > >

Figure 1: The same passage as written (la) and as performed (lb). Both examples here are from the "St Louis Blues

unexplored. Some of the algorithmsthat adaptively follow varying-rateMorse code may be useful. A numberof moderately successful programs,all quite large and complex (usingmany techniques from artificialintelligence work, and not operatingin real time), have been created. [TheOctober 1976 issue of BYTE con-tained several discussions of Morse-code decoding problems. . . .RSS]

If you first succeed with rhythm,then you might have a chance at therest of the problem. At least a goodportion of the problem of transcrib-ing a musical performance into astandard score will have been solved.

More and Less

It is clear that a performance of apiece often contains more informa-tion than is given in the score: thingshappen in the performance that arenot specified in the written music.Jazz, usually played from sketchy"charts," is an especially good exam-ple. The lilting "dotted" rhythms ofjazz are notated as equal notes on thepage. But everyone "knows" how itshould sound. Look at the examplefrom W C Handy's "St Louis Blues" infigure 1.

It is clear that the performance infigure lb is quite different from thewritten notation in figure la, as itmust be in order to sound right. Thefigure shows just one possible way ofsinging the opening measure of thechorus to the "St Louis Blues" (and itis not an especially extreme example).

It is rare, if not unheard of, thattwo live performances are the same.Some of the changes are minor, suchas changing two eighths to a dottedeighth and a sixteenth. More surpris-ing is the modification of the openingtwo eighth notes into half notes (witha ritard, no less). But that is the way

it is done.

Strangely enough, the same con-vention about playing eighth noteswith a certain uneven lilt occurs inmuch baroque music, in spite of thefact that the notes were written downas being of equal length. Many per-formances of Bach's music, for exam-ple, are marred by a "wooden" play-ing of such passages.

Many conductors and performersplay baroque music exactly as it isnotated. It sounds as if you triedplaying jazz or rock exactly as writtenin songbooks and sheet music: theresult is dull music. This may help toaccount for some of the commentsabout baroque music sounding like amelodic sewing machine—some per-formers play it as though their in-

INPUTS

MusicalIdea

Score

Keypresses

Sound

Inspiration

Plagiarization

Stimulation

SynthesizedMusic

MusicalIdea

Composition

Arranging,Copying

Transcription

TakingDictation

Score

Improvisation

Performance

Coupling

PlayingBy Ear

Keypresses

"ScienceFiction"

Automation

"Sonification"

Transmission

PerceivedSound

0

u

TP

u

TS

Table 1: Musical transformations, representing the various ways of obtainingmusical results. The table is read by starting at the top at a given input and pro-ceeding downward and to the right to read the output. The shaded example il-lustrates that the term performance describes the connection between a printed scoreand the production of keypresses. (For simplicity's sake, the table deals only withkeyboard instruments.) Similarly, to go from a musical idea (ie: input) to a score fie:output) requires "composition. " The term coupling refers to the mechanical additionof extra voices to an organ keyboard so that the organist can play more than onepipe with a single keystroke. Automation refers to the procedure by whichmechanical musical instruments (such as music boxes and player pianos) take a scorein machine-readable form and generate perceived sound. For want of a better word,sonification is used to describe the production of perceived sound from pressing akey on a keyboard. The terms in the row called "musical idea" are meant to be takentongue-in-cheek.

124 May 1980 © BYTE Publications Inc

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struments were sewing machines,without any regard for the originalstylistic intent.

Problems Caused by Repeats andLarger Musical Structures

Here is another dilemma: how cana computer (or a human) tell if a sec-tion of a piece being performed hasbeen repeated (perhaps with embel-lishments), or if it is a new section

merely similar to the old one?

For example, in a Mozart rondo forthe piano, almost all of the embel-lishments will be written out in full.In a Mozart sonata for the piano,there will usually be repeats markedand any variety will be at the per-former's option. Does this mean thatthe computer must first be told theform of the piece before it cantranscribe it? Knowing the form of a

¥^f

ST

Q.

12

©-

:* "o

Figure 2: Example of the equivalence of two musical notations. The chords notated hereare played the same way on a keyboard instrument and sound the same, but they arewritten in different ways. This difference, however small, subtly influences the waymany musicians interpret the chord.

Oa)

(3b)

(3c)

11-^ tt *-m

~m-

•

r

IB *T^

Figure 3: Different notations for the same sounds. The three melodies here, whenplayed, will sound exactly the same; the only difference is the choice of clef and acciden-tals. The first two melodies are written in the keys of A-flat Major and G Major in trebleclef; the third melody is in the key of D Major in soprano clef.

(4a)

(4b)

m

T

Figure 4: A musical phrase played with two different voicings. These two phrases maysound the same, but the two correct, differing notations convey different meanings to amusician.

piece beforehand certainly aids ahuman transcriber.

Again, there is vague and generalinformation that must somehow findits way into the program. As inhaving the computer play chess,methods have been found fortranslating an imprecise notion (eg:control the center of the board) intoalgorithms. Chess is a rich field, rifewith human invention and complexi-ty. Music is a more complex environ-ment.

Problems With Notating Pitch

Having shown that there is infor-mation in a performance that is not tobe found in the score (this is alwaysthe case), I would like to show thatoften there is information in the scorethat cannot be gleaned from the per-formance. The "spelling" of chords isone example. The two chords infigure 2 sound exactly the same onour equal-tempered organ. Neverthe-less, they would be thought of dif-ferently by a musician playing them.

The notes of the two chords actual-ly represent different pitches if sungor played on violins (or any instru-ment which allows the performer tovary pitch continuously rather thanin discrete steps, as with an organ orpiano).

The three sets of melodic notes infigures 3a thru 3c sound the same,and are all correctly but differentlynotated. Again, a human might guesswhich is tht correct notation bymeans of global information, themusical context in which the passageoccurs. In this example, the globalinformation is the key of the pieceand the customary clef of the instru-ment that is to play the tune. Is itreasonable to have the user predeter-mine the key for the computer? Orshould the computer wait, as ahuman often must do, until the veryend of the piece has been playedbefore beginning to write it down?

Problems Transcribing NotesSounded Simultaneously

On keyboard instruments such asthe organ or piano, the performer caneasily sound more than one note atany given instant. These notes mayform a chord, or can be thought of astwo or more melodies that are beingplayed at the same time. In this lattercase, each melody is called a voice.(This use of the word "voice" in musicdoes not imply singing.) Multiple,

126 May 1980 © BYTE Publications Inc

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simultaneous voices bring anotherhost of difficulties to the attempt foraccurate transcription.

It is nearly impossible for even anexpert musician to determine un-ambiguously, from listening alone,which note should be allocated towhich voice. I realize that this portionof the discussion is delving heavilyinto the terminology of music, but theintricate details of music are whatmake this problem so fascinating.The two segments of music in figures4a and 4b sound the same, and areboth notated correctly. Nevertheless,the differences are significant and use-ful to the musician performing themusic.

This is not the place to go furtherinto the musical significance of thesenotational differences. Enough ex-amples of problems have been amass-ed to give you a starting place atwhich to begin to think about havinga computer "listen" to and "under-stand" music.

Problems in DeterminingPitch With a Computer

If things were not difficult enoughgiven direct input from a keyboard,

many people (eg: ethnomusicologists)would love to be able to play a re-cording into a computer and producea written score. So would I.However, two new problems are in-troduced. Finding what pitch is beingplayed is not easy. To be sure, a sim-ple sine wave could be digitized by afrequency counter. Unfortunately,real musical sounds are far more com-plex, often having harmonics andovertones that make almost anyfrequency-determining method un-sure. And what do you do when anote slides from one frequency toanother (portamento in musicaljargon)? Or when a chorus finishessinging a chorale a semitone lowerthen when they started—will thecomputer notate it as a suddenmodulation in the middle?

Even determining how long a notelasts is difficult. Try playing a pianonote; strike a key and hold it down.How long does it last? Just when doesits gradual dying away cease? In aquiet room, with a good piano, itmay take several minutes. You mightas well ask where the rainbowchanges colors. Musical sounds oftendo not have well-defined edges with

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respect to time or pitch.

Summary

The point has been made, and it ispossible to show many more ex-amples than have been shown herethat you cannot go from a perfor-mance to a score, or vice versa, inany easy fashion while preserving thequalities that make the notation ofmusic readable to most musicians andthe properties of a performance thatmake it worthwhile listeningmaterial.

A score is a highly idiomatic ren-dering of a piece of music, and a pieceof music is a unique instance of thecomposition that the composer had inmind when the score was written.

These facts assure that the buildingof a perfect music transcriber isliterally impossible. Whether it ispossible to make the Composer's Aidgood enough for most practical pur-poses remains to be seen. If we putlow enough limits on the idea of"good enough," I am sure that it canbe done quite easily. If it is to satisfyme (and musicians of like mind), itwill probably not be easy at all.

A final suggestion: if you want totackle any project of this sort, makesure that you know music well. Alsomake sure that you know your com-puting well or forge a partnershipthat can provide the needed ex-perience. I have met many peoplewho do not know the first thingabout music trying to achieve dif-ficult goals combining computers andmusic. I have also met musicians whoimagined that they could get the com-puter to do some task that they foundvery easy—only to discover that theydid not understand the difficulty ofwhat they themselves could easily do.

The greatest benefit the computerconfers upon mankind is that it forcesus to truly understand what we aredoing, for it is only through suchunderstanding that we can instruct acomputer. ■

Acknowledgments

/ would like to thank the many people whohave made useful suggestions about this article,and I would like to specially mention DougWyatt of the Xerox Palo Alto Research Centerfor many useful discussions about the nature ofmusic, Brian Howard of Apple Computer Cofor his excellent editing and criticisms, andboth of them for the many hours of rehearsal,performance, and programming that they haveshared with me.

128 May 1980 © BYTE Publications Inc

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Comparing Floppy-Disk Drivesby Software Simulation

Large companies learned long agothat preliminary performancespecifications of systems can bepredicted reasonably well by com-puter simulation. The NationalAeronautics and Space Administra-tion (NASA) saved much money andeffort by simulating numeroussystems that have been developed forthe space program. In a somewhatsmaller way, microcomputers can beused to simulate a variety of opera-tional systems. Complex equationsand analysis are not always required.

Here I shall present a practicalsimulation. I have chosen a topic ofinterest to myself and many small-computer enthusiasts: a comparisonof the operating speeds of floppy-diskdrives. This article will explain basicmechanical drive movements and il-lustrate the transformation of thesephysical events into the algorithmicsteps of a computer program. Esti-mating one drive's performance inrelation to others is the goal.

To do such a comparison, we needsome knowledge of the operationalparameters of floppy-disk drives.These parameters are the lengths oftime required for a drive to perform agiven function. All drives have atleast these four parameters:

• head load

• seek

• rotational latency

• data-transfer rate

1 shall look at each function in detail.

Head-Loading Motion

Before any data can be located or

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transferred on some drives, the data-transfer head must be loaded; firmcontact between the head and the disksurface must be assured. To accom-plish this, a pressure pad is placedagainst the disk on the side oppositethe head. This pressure pad move-ment is referred to as loading thehead. The length of time required tomove the pad into place and insurethat all mechanical bouncing hasstopped is termed head-load time.Look at figure 1 to see a diagram ofthe head-load mechanism.

Track-Seeking Motion

Once the head is loaded, it may benecessary to move the head to a posi-tion over another data track on thedisk. In most drives, the track-to-track movement, or seeking, isaccomplished by a stepper motor.This motor rotates in steps of fixed,discrete increments; a specific intervalof time is required for each incre-mental movement. Thus, to move thehead across X tracks takes an amount

of time equal to X intervals. Once weknow the time interval required toperform a movement and the numberof tracks to move across, we canpredict how much time it will take thehead to reach the desired track.

All stepper motors exhibit somevibration at the end of the last step ina given movement. There may be asettling time required before a read orwrite operation can begin.

Another type of motor is used infloppy-disk drives such as the PerSciModel 277. It is called a linear motorsince it produces linear motion direct-ly. The method is also called "voice-coil" positioning, due to the similarityto the action of a loudspeakermechanism. Figure 2 depicts thestepper- and linear-motor positioningsystems in simplified form.

The amount of time required pertrack for the linear motor to performa seek operation varies according tothe total number of tracks to beskipped. Unless the manufacturersupplies data describing the seek-time

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130 May 1980 © BYTE Publications Inc

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function, it must be derived fromempirical measurements. This deriva-tion, however, is not within the scopeof this article.

Rotational Latency

Reading and writing operations areequivalent functions with respect tothe actual time required for comple-tion. With that in mind, the discus-sion will proceed as if a read opera-tion is being executed. Assuming thatthe head is now loaded and posi-tioned over the proper track, it re-mains for us to examine how long adelay may be expected in waiting forthe desired record to spin past thehead.

A look at figure 3 shows how mostsoft-sectored disk formats appear.Actually, the soft-sectored formatcontains 128 bytes of user data; theother data locations are used asaddress marks and gaps between cer-tain fields. To determine the extent ofthe delay that must be endured beforethe desired sector is available, I willconsider two cases.

The first case occurs when we begina read operation and find the correctsector just about to pass by the head.In this event, there is no wait or laten-cy, as it is called, before starting thetransfer of data. The second caseshows that the beginning of thedesired sector just went by an instantbefore the read operation was started.We must now wait for one full rota-tion of the disk, or the maximumrotational latency, for the record toappear at the head again. These twoextreme cases show that there arewell-defined minimum and maximumrotational latencies. Of course, mostdelays will be at some random pointwithin this range for actual readoperations. The absolute delay for asingle read operation is not predict-able, but the average for a group ofread operations is predictable withinlimits.

Data-Transfer Time

Finally, there is the most obviousfunction of the disk drive, datatransfer. Data-transfer time isdependent on three basic parameters:disk rotational speed, data density,and format. The faster the disk sur-face spins past the head, the faster the

132 May 1980 © BYTE Publications Inc

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head can read the data. (Large 8-inchdisks spin faster than the smaller5-inch disks.) The higher the density,the more data can be transferred in agiven interval of time. Format dif-ferences can account for differenteffective transfer rates on largerecords, but will not be dealt with inthis simulation. I will deal primarilywith the standard IBM 3740 soft-sectored, 8-inch floppy-disk format.

Building the Simulation

We now have an understanding ofwhat happens when a function of thefloppy-disk drive is requested. Wecan now construct a program frame-work that will use this information.To read or write a record, we mustpass through four distinct states:head-loading, track-seeking, rota-tional-latency waiting, and data-transferring. To compute the actualtime required to pass through thesestates, we must get some informationfrom the manufacturer's specifica-tions for a given drive. Typically, themanufacturer will list the time forhead load, track step, average laten-cy, and sector transfer in milli-seconds.

Head-load time calculation is easy.Each time that the head is loaded, avalue corresponding to the head-loadtime is added to a total-time accumu-lator. As a matter of practice, mostdrives and control software leave thehead loaded for a fixed-time intervalfollowing a disk operation. Thisreduces head-loading delays andacoustic noise, but it also increasesdisk surface wear slightly. For mostprograms (such as assemblers) thatengage in almost continuous diskactivity, the head will probably gothrough the load cycle only once dur-ing an execution of the program.

Computation of track-step time isnot difficult in most cases. We merelyfigure the number of steps we mustmake from the current track to thedesired track, and multiply that valueby the specified track-step time. Donot forget to add the settling time, ifthe manufacturer gives it. (Rememberthat the settling time indicates thetime taken by the head to stopvibrating from its track seeking andto start reading.)

Thus, for disk drives using stepper

134 May 1980 © BYTE Publications Inc

Circle 77 on inquiry card.

Circle 78 on inquiry card.

Diagnostics I •» ^* ™Sdos

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motors, the seek time is the absolutevalue of the distance from the currenttrack to the desired track multipliedby the track-step time, all added tothe settling time, or:

T„„ = ABS(PC,

— P-

?N 1 step T" 1 settling

where T is used for values of time,and P shows the position of the headin relation to data tracks on the disk.

But what should be done when thedisk drive uses the linear-type motorsto move the head from track to track?The specification sheets for the PerSciunit give only a single-track seek timeof 10 ms. Is that the same as thestepper-motor drive timing? No—thistiming is for a single-track step, andthere is no settling time to be added.In fact, if the two-track seek time ismeasured, it is one and one-half timesthe single-track seek time. If a ten-track seek is measured, we find that ittakes only three times as long as mov-ing the head a distance of one track.

Well then, what can be done aboutthis device? For this simulation, myplan of attack was direct. I merely

measured the time that it took for allpossible seek distances (seventy-sixvalues) and then computed an ap-proximating function by using a least-squares polynomial curve-fit calcula-tion. The concepts behind this com-putation are not simple. Fortunately,the routine is adaptable from a bookthat addresses such problems, DataReduction and Error Analysis for thePhysical Sciences by Philip R Bev-ington (McGraw-Hill Book CompanyInc, 1969).

When the seek time for the PerScidrive is needed in my simulation, thenumber of tracks the head crosses isevaluated and is given as an argumentto the empirically derived seek-timefunction. The result of the functionevaluation is the number of milli-seconds required to complete theseek. Thus, the PerSci drive becomesa special case in the simulation, buthandling it is not so awkward.

To compute the rotational latency,one of two possible techniques is em-ployed. For any large number of dis-crete read operations, the actual, av-erage rotational latency experi-enced will approach one-half of the

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maximum latency. This value can beused for each read operation as a typ-ical latency. I prefer to calculate arandom latency for each read opera-tion. Approximately the same resultswill appear as in the first method for alarge sampling of read operations.You will notice that the results fromusing random latency values are notlikely to be the same each time theprogram is executed. This is due tothe accumulation of random variabil-ity, which is an effect you would seeif the simulation were carried out onreal hardware as well as in a pro-gram. The function for randomly de-termining a latency time is simply:the value of the maximum latencymultiplied by a random number be-tween 0 and 1.

The final item which must be dealtwith is the actual time it takes thedrive to transfer the data to (or from)the disk. The time to transfer 128bytes of data has been chosen for thissimulation. The time values for eachdrive in this simulation were calcu-lated based on the rotational speedand data density. Record overheadbytes and interrecord gaps were notconsidered. In the simulation pro-gram, the computed values arereflected in the appropriate field inDATA statements that describe thecharacteristics of each drive. Transfertime for n bytes is calculated bymultiplying n by 8, and then dividingby the transfer rate, in bits persecond.

About the Simulation Program

Now that we understand the basicdrive mechanics, there should be nodifficulty in comprehending how thesimulation works. The program per-forms two simulations for each diskdrive under consideration.

The first simulation is a set of 500sequential-read operations, as youwould find in a sequential file-copyoperation. The second simulationinvolves a random reading of 500records, as you might encounter in aprogram that reorganizes an indexedfile according to an unordered secon-dary key field.

These two modes of access willexhibit the characteristics of generalinterest concerning floppy-disk driveperformance. Briefly, the programsteps through the DATA statementsthat supply the drive name andparameters for that drive. Bothsimulations are run for a given drive,

136 May 1980 © BYTE Publications Inc

Circle 79 on Inquiry card.

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Circle 80 on inquiry card.

BYTE May 1980 137

and the results are printed. Look atthe program shown in listing 1 to seethe simple logic and computations.

Results and Notes

If this simulation were run using atrue random-number generator, youwould find that the resulting timingswill vary on each run. As, notedearlier, this is random variation thatis to be expected. Do not expect to seeexactly the same results as printedhere; the values will be within a fewpercent on all runs.

Referring to the simulation outputshown in listing 2, observe that, onsequential-read operations, the

transfer times for the 5-inch floppy-disk drives are about 25% slowerthan the times for the standard size(ie: 8-inch) drives. Allowing for ran-dom variation, this is very close tothe 20% speed difference that mightbe predicted based on the differentrotational rates of the two sizes offloppy disks. The 8-inch disk drivesalso outperform the 5-inch drivesduring random-access operations.Most, but not all, of the smallerdrives are slower in seeking fromtrack to track, and this really showsduring random access.

The fastest-seeking drive of thegroup, the PerSci Model 277, does

not get a chance to show off whilereading sequentially, but its capabili-ty becomes apparent during random-access operation. This device reallymoves the head fast! The second andthird places go to the MemorexModels 552 and 550 respectively;these use fast stepper-motor drives.

Now that you have read this far, Ican reveal some bad news concerningthis simulation. The timings obtainedare not likely to be a true indicationof how long it would take to actuallyperform these operations on a run-ning computer system. Accomplish-ing so realistic a simulation involvesadditional simulation of the interface

Listing 1: Program to simulate mechanical characteristics of various 8-inch and 5-inch floppy-disk drives, written in BAS1C-E andrunning under the CP/M operating system. One step is the simulation of 500 sequential-read operations; the other is the simulation of500 random-access read operations. Due to the use of random numbers, some variation of results is expected between different execu-tions of this program.

PROGRAM TO COMPARE ACCESS TIMES OF VARIOUS FLOPPY-DISK DRIVES FORSIMULATED SEQUENTIAL AND RANDOM READING.

THE FIRST TEST IS FOR 500 SEQUENTIAL READS, 128 BYTES PER READ.STARTING TRACK IS 0. THE HEAD IS LOADED AND REMAINS LOADED.WHERE A DRIVE HAS SECTORS GREATER THAN 128 BYTES, THE SECTOR TRANSFERRATE HAS BEEN ADJUSTED IN THE DATA FOR THAT DRIVE.

ALL TIMES ARE IN MILLISECONDS.

REM

REM

REM

REM

REM

REM

REM

REM

REM

REM

READ DRIVES REM GET NUMBER OF DRIVES TO SIMULATE

INPUT "ENTER ANYTHING TO SEED THE RANDOM-NUMBER GENERATOR";A$

PRINT : PRINT : PRINT REM UPSPACE A FEW LINES

PRINT TABOO); "FOR 500 READ OPERATIONS"

PRINT TAB(25); "DRIVE SPEED COMPARISON SIMULATION"

PRINT TAB(30); "ALL TIMES IN MILLISECONDS"

PRINT

PRINT "DRIVE NAME"; TAB(25);"SEQUENTIAL";TAB(40);"RANDOM"

PRINT TAB(25);"- + "

PRINT

RANDOMIZE REM SHAKE UP RANDOM-NUMBER GENERATOR

FOR D = 1 TO DRIVES

READ DNAME$,TTRK,TSETL,HLOAD,LATENCY,SECREAD,NSECS,NTRKSCURTRACK = 0 REM STARTING TRACK

TOTALTIME = 0 REM SET TIME ACCUMULATOR TO 0

REM LOAD THE HEAD ONCE FOR THIS SEQUENTIAL TEST

GOSUB 1000 REM GO ACCUMULATE HEAD-LOAD TIME

FOR I = 1 TO 500 REM 500 SEQUENTIAL READS LOOP

GOSUB 2000 REM STEP TO NEXT TRACK IF NEEDED. ACCUMULATE TIME

GOSUB 3000 REM READ NEXT RECORD. ACCUMULATE TIME

NEXT I

REM PRINT RESULTS FOR TEST 1

PRINT DNAME$;TAB(28);INT(TOTALTIME'10)/10;TAB(40);REM NOW FOR 500 RANDOM READS IN A FILE 35 TRACKS LONGTOTALTIME = 0 REM SET TIME ACCUMULATOR TO 0

LOWTRACK = 0 REM LOWER FILE TRACK LIMIT

HIGHTRACK = 34 REM UPPER FILE TRACK LIMIT

CURTRK = 0 REM START AT TRACK 0

FOR 1= 1 TO 500 REM 500 RANDOM READS LOOP

NEXTRK - LOWTRACK + INT(RND*35) REM NEXT RANDOM TRACK

TRACKSTOMOVE = ABS(CURTRK-NEXTRK) REM NUMBER OF TRACKS TO TRAVERSE

GOSUB 2500 REM COMPUTE TIME TO DO SEEK. ACCUMULATE IT

GOSUB 3000 REM COMPUTE RECORD READ TIME. ACCUMULATE IT

CURTRK = NEXTRK REM NEXT TRACK HAS BECOME THE CURRENT TRACK

NEXT I

PRINT INT(TOTALTIME* 10)/10 REM PRINT RANDOM READ RESULTS

NEXTDSTOP

REM SUBROUTINES FOLLOW1000 REM ACCUMULATE HEAD-LOAD TIME Listing 1 continued on page 140

138 May 1980 © BYTE Publications Inc

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42

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This machine language programmodifies your copy of the Radio ShackEditor/Assembler for use with yourminidisk and any disk operating system.You can save and load both text sourceand assembled object files. Unlike theNEWDOS+ version you can read thedirectory and the allocation ofgranules while in the EDTASM. You canalso kill files. It is a complete diskmodification for one or more drives.

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BYTE May 1980 139

Listing 1 continued:

TOTALTIME = TOTALTIME + HLOAD

RETURN2000 REM COMPUTE SEQUENTIAL TRACK READ-SEEK TIME

IF I/NSECS NE INT(I/NSECS) THEN RETURN REM NO TRACK ADVANCE

2500 IF TTRK = 0 THEN 2800 REM USE SPECIAL PERSCI FUNCTION

SEEKTIME = TRACKSTOMOVE.TTRK + TSETL REM COMPUTED SEEK TIME

2600 TOTALTIME = TOTALTIME + SEEKTIME

RETURN2800 REM PERSCI-277 DERIVED SEEK TIME FUNCTION

IF TRACKSTOMOVE = 0 THEN : REM NO MOVEMENT REQUIRED

SEEKTIME = 0: REM THEREFORE SEEKTIME IS ZERO

RETURN

X = TRACKSTOMOVE

SEEKTIME = 10.89605 + 2.178647. X-4.846975E-2.X.X + 7.936448E- 4. X.X.X-4.406022E- 6. X.X.X.X

GOTO 26003000 REM COMPUTE RECORD READTIME INCLUDING ROTATIONAL LATENCY

RNDLATENCY = INT(RND. LATENCY) REM RANDOM ROTATIONAL LATENCY

TOTALTIME = TOTALTIME + RNDLATENCY + SECREAD REM ACCUMULATE READ TIME

RETURNREM FIELD ORDER IN DATA STATEMENTS

REM DRIVE NAME, TRACK-TO-TRACK TIME, SETTLING TIME, HEAD-LOAD TIME,REM MAX LATENCY, TRANSFER TIME, SECTORS PER TRACK, TRACKS PER DISKDATA 12 REM NUMBER OF DRIVES TO SIMULATE

DATA "PERSCI 277",0,0,40,166.7,4.096,26,77DATA "REMEX RFD 1000A/B",6,24,50,166.7,4.096,26,77DATA "SHUGART SA800",8,8,35,166.7,4.096,26,77DATA "SHUGART SA400 MINI",40,10,75,200,8.192,18,35DATA "SHUGART SA450 MINI",25,15,50,200,4.096,18,35DATA "PERTEC FD200 MINI",25,10,35,200,8.192,16,35DATA "ICOM FD3800 DUAL-DENSITY", 10,0,40,166.7,2.048,26,77DATA "ICOM MICROFLOPPY",40,10,75,200,8.192,16,35DATA "MEMOREX 550",6,10,35,166.7,26,77DATA "MEMOREX 552",3,15,35,166.7,26,77

DATA "MICRO PERIPHERALS B51 MICROFLOPPY",5,15,35,200,8.192,16,40DATA "ALTAIR 88-DCDD", 10,10,45,166.7,4.096,32,77END

and software delay characteristics.However, the relative standing of thedrives is unlikely to change if thesefactors are included.

The important elements to considerfor additional simulation are: therecord formats on the disk, the inter-face and controller characteristics,processor speed, and the algorithm ofthe program performing the access.

As an example of the discrepancy

between the simulation and the speedof the total system, I offer the follow-ing. My system uses a Z80 micro-processor running at a 2 MHz clockrate, and contains 24 K bytes of zero-wait-state memory. The drive con-troller, designed by George Morrow,connects to a PerSci Model 277 withthe fast-seek option. The operatingsystem is CP/M. The time to read 500records sequentially using BASIC-E is

Listing 2: Output of simulation results produced by the program of listing 1.

FOR 500 READ OPERATIONS

DRIVE SPEED COMPARISON SIMULATION

ALL TIMES IN MILLISECONDS

DRIVE NAME

PERSCI 277

REMEX RFD1000A/B

SHUGART SA800

SHUGART SA400 MINI

SHUGART SA450 MINI

PERTEC FD200 MINI

ICOM FD3800 DUAL-DENSITY

ICOM MICROFLOPPY

MEMOREX 550

MEMOREX 552

MICRO PERIPHERALS B51 MICROFLOPPY

ALTAIR 88-DCDD

SEQUENTIAL

+

RANDOM

43107.6

57912.2

43650.1

92281.9

44163.1

94881.9

53547.8

288397.1

55153.2

198631.3

52804.8

201703.6

43110.0

101456.6

55698.8

293376.0

44821.1

77892.1

44000.1

66670.3

55287.8

89390.2

42634.1

108670.8

109 seconds; to read 500 records ran-domly takes 525 seconds. Comparethese times with those in the results ofthe simulation for the PerSci drive.Beware of making system estimatesbased only on a part of the totaloperation. Does anyone want towrite an article that describesoperating-system timing simulation?

Two for One

There are two basic lessons to belearned from this exercise. The firstone concerns an elementary introduc-tion to the motions that occur infloppy-disk drives and affect theirspeed of operation. The second lessonconcerns derivation of mathematicalfunctions that describe thesemechanical motions; it also concernsputting the functions into a programfor the purpose of obtaining anestimate of performance. Perfor-mance, for the purpose of this article,considers only the relative speed ofoperation of the various drives. Inmaking a decision to select a par-ticular floppy-disk drive, you mustunderstand that overall performance,not just speed of operation, should beexamined. ■

140 May 1980 © BYTE Publications Inc

IDS Announces

S-100 Energy Management Module

The 100-EMM Energy Management Module provides temperature measurement at four separate locationsindoors or out; monitors eight (8) doors, windows, or fire sensors; controls six external devices via relay or op-toislator; and provides an intrusion alarm with battery backup (alarm operates even during primary power out-ages) . Put the 100-EMM to use in your home or business and claim a 30% tax credit for the cost of your S-100computer system including the 100-EMM. (Purchasing the 100-EMM can actually save you several times itscost in tax credits. Full instructions for filing are included in the 100-EMM manual.)

BUY THIS S-100 BOARDAND GET UP TO A 30%TAX CREDIT BASED ONTHE COST OF YOURCOMPUTER SYSTEM!

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Options for 100-EMM:

CP-52 Cable Panel - Terminates two 26-conductor flat cables in 26 screwlugs. Use it for convenient interconnection of the 100-EMMto the "outside world". $45.00

CABL-26-STD 26-Conductor Flat Ribbon Cable - Four feet in length with connectors for 100-EMM and CP-52 above. $35.00 Otherlengths available on special order. Add $1.00 per foot.

OTHER PRODUCTS FROM IDS. The most complete source of S-100 compatible modules for process con-trol, data acquisition, energy management, and data communications.

88-MODEM S-100 ORIGINATE/ANSWER MODEM WITH AUTO-DIALER. Software selectable baudrate provides any baudrate from 66-600 baud. Provides 1.5 stop bits when operated in 5-bit code mode.Auto-answer programs available for CROMEMCO CDOS, CP/M, NorthStar Horizon and MDS, and Alpha Micro.

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Four software selected inputs. Measure frequency from O-650MHz and period from .luS to 1 Second. Extensive software in-cluded.

Assembled and Tested $299.00 Kit $199.00 Temperature-Compensated Crystal Oscillator option $145.00

88-SAI SYNCHRONOUS/ASYNCHRONOUS INTERFACE

The most versatile serial interface on the market. Computer ac-cess/control of all data and handshake lines and provision formasked interrupts, inversion of any input or output signal, andonboard baudrate generation for 110, 134.5, 150, 300, 600,1200, 2400, 4800, 9600, and many other baud rates. Manymore features.

Assembled and Tested $299.00 Kit $199.00

88-SPM TIME OF DAY CLOCK with battery backup. Set theclock with three out instructions: no delays! Programs includedin North Star BASIC, CBASIC, and 8080 assembly language.

Assembled and Tested with crystal option $199.00 Kit lesscrystal option $99.00 Crystal Option Kit $25.00

88-RCB RELAY CONTROL BOARD

16 Relays on one board. Control appliances, production equip-ment, or even musical instruments (See BYTE Magazine Sept1977 page 12)

Assembled and Tested $299.00 Kit $199.00

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TELEX 901112 IDS CTLY

Circle 82 on inquiry card

BYTE May 1980 141

iiiiiiliii^iiiJLiiiirtWir

COMPUTER SYSTEMS

*Z80 is a registered trademark of Zilog. Inc.

*CP/M and MP/M are registered trademarks of Digital Research, Inc

ALTOS BREAKSTHE MICROBARRIER.

Yesterday, microcomputer meant microperformance. Once you outgrew it, you had to stepup to a mini. Which meant a big step up in price.

Today, there's the new Altos ACS8000-6 single-board microcomputer system.

It's the first system for the OEM, small business-man and personal user, that offers minicomputerperformance and minicomputer storage capacities—at a microcomputer price.

MULTI-USER, WINCHESTER STORAGE,FLOPPY BACK UP: $14,260.

The new Altos ACS8000-6 is a highly advancedZ80* based microcomputer system with high-speedRAM, floppy disk and Winchester harddisk controllers, DMA, six serial andtwo parallel I/O ports and the AMD9511 floating point processor all ona single board. Atypical four-usersystem configuration with twomegabytes of Shugart floppyand 29.0 megabytes of ShugartWinchester storage, includingCPU and 208K bytes of RAM,costs only $14,260—com-pared to $30,000 or more fora similar minicomputer system.And that adds up to miniperformance at less than halfthe cost!

MULTI-USER EXECUTIVE

SUPPORTS FOURINDEPENDENT USERSRUNNING CP/M**COMPATIBLE PROGRAMS.

This revolutionary new microcomputer systemfeatures the MP/M** Multi-User Executive softwareprogram that's unique in two ways. It includes amulti-user CP/M capability and the ability to handleWinchester-type hard disks. The advanced Z80operating program supports four independent CP/M

compatible programs in any of six popular lan-guages: BASIC, FORTRAN, COBOL, PASCAL, APL,C, and a large assortment of additional businessapplication packages. MP/M is compatible with boththe 1.4 and 2.0 versions of Digital Research'sCP/M, which means programs based on eitherversion can run under MP/M without modification.

With MP/M at the helm, your AltosACS8000-6 system can support up to four simul-taneous users with 48K bytes of RAM each plus58 megabytes of Winchester storage and 4 mega-bytes of floppy back up. And that adds up to thefirst microcomputer to give you the power and

performance of a minicomputer.SINGLE-USER, HARD-DISKSYSTEMS START AT 59450.The Altos ACS8000-6series. It's a barrier breakerin every sense. Our entry-level, single-user, hard-discsystem with floppy backup is priced under $10,000and even our 4-user CP/Mmodel is available forunder $12,000. And allconfigurations are easilyupgraded. For specificdetails about pricing orperformance, call or write:Altos Computer Systems,2360 Bering Drive, San Jose, CA(408) 946-6700. TELEX 171562 ALTOS SNA.

Circle 83 on Inquiry card.

COMPUTER SYSTEMS

BYTELINES

NEWS AND SPECULATION ABOUT PERSONAL COMPUTING

Conducted by Sol Libes

w,

hat To Look For AtNCC: The computer showof the year is the Na-tional Computer Con-ference (NCC), which willbe held this month (May19 thru 22) at theAnaheim ConventionCenter in Anaheim,California. In 1979,60,000 people attendedthe NCC. Many new pro-ducts are introducedeach year at NCC. The1980 show will see manymore Japanese manufac-turers displaying, amongother things, 8-inch Win-chester disk drives andmicrocomputer systems.Furthermore, look forseveral manufacturersfrom the United States toshow complete microcom-puter systems that usethe Zilog Z8000 andMotorola 68000 16-bitmicroprocessors. Lastyear's show saw the in-troduction of 8086-basedmicrocomputers. Also,look for disk-operating-system-based languagesand applicationspackages for these new16-bit microcomputersystems. Severalmultiprocessing andmultiuser microcomputersystems will also beshown.

%9 ohn Mauchly, Com-puter Pioneer, Dies: Dr

John W Mauchly, co-inventor of the digitalcomputer, died onJanuary 8, 1980 at theage of 72. Together withhis colleague Dr JProsper Eckert, DrMauchly conceived,designed, and builtENIAC, the first elec-tronic digital computer.

It was built at theUniversity of Penn-sylvania and becameoperational in 1944.ENIAC containedthousands of vacuumtubes, filled 150,000square feet of space, andweighed 30 tons. It wasused for ten years.

Mauchly and Eckertlater formed the Elec-tronic Control Company(later called the Eckert-Mauchly Computer Cor-poration) to manufactureBINAC (Binary AutomaticComputer), which becamethe prototype for theUNTVAC I (UniversalAutomatic Computer).The UNTVAC I was thefirst commercial com-puter; it was installed atthe United States CensusBureau in 1951.

When the company waspurchased by Remington-Rand in 1950, DrMauchly continued withthe Univac Division asDirector of Applicationsand worked on weather-forecasting projects. In1959 he left to formMauchly Associates, aconsulting firm thatdeveloped the critical-path method for con-struction.

In 1967 he foundedDynatrend, a computerconsulting firm, andsince 1973 he had servedas a consultant to SperryUnivac.

Mauchly and Eckertmet in 1941 at theUniversity of Penn-sylvania's Moore Schoolof Electrical Engineering,where both were instruc-tors. They first proposedthe building of the digitalcomputer to the US Armyin 1942 for calculating

trajectory tables. ENIACcontained ten ac-cumulators, had internalmemory, usedsubroutines, and was all-electronic, while priormachines were elec-tromechanical and verylimited in power. Someparts of ENIAC can beseen at the SmithsonianInstitution inWashington, DC.

At the time of his deathDr Mauchly was believedto be working on a word-processor project using aRadio Shack computer.He was an active propo-nent of personal com-puting, and he will bemissed by many.

N,

I ews Bits: FriendsAmis has developed aninterface for the CraigM-100 hand-heldlanguage translator thatallows the user to addread-only memories con-taining data bases suchas wine lists, Olympicscores, history, or metricconversion.... Panasonicwill introduce a hand-held computer to sell forabout $180 in late 1980.The RLT500 ElectronicData Center can be con-nected to a television setfor display, to anacoustic modem for com-munication, to a printerfor hard copy, or to aspeech synthesizer foraudible output. Quasarwill bring out theHC2000RA InformationProcessor for $150,which should work withthe accessories for thePanasonic machine....Amateur robot buildershave a new source forparts: Vedos Ltd, Suite

1113, 19 W 34th St, NewYork NY 10001.

Xmandom News Bits: In

last month's column Imentioned a rumor abouta new printer to competewith the SandersTechnology word-processing dot-matrixprinter. The unit hasnow been formally an-nounced by Florida DataCorporation of WestMelbourne, Florida. It of-fers up to 900 charactersper second (cps) speedwith correspondence-quality type and high-resolution graphics (at aslower speed). It is saidto use a magnetic stored-energy print head, and tooffer an almost unlimitedchoice of type fonts, fullgraphics, and extended-character format. Themachine will be availablein the fourth quarter of1980, and it should bepriced under $2000....Micro Peripherals Incor-porated of Salt LakeCity, Utah, plans anunder-$1000 word-pro-cessing printer using aseventeen-wire matrixhead and printing at 60to 75 cps.... In the mean-time Diablo, Qume, andNippon Electric Company(NEC) are rumored to bedeveloping under-$1000daisy-wheel printers....Dataproducts will soonintroduce a daisy-wheelprinter; some observersspeculate that it will sellfor 20 to 30% less thancurrent daisy-wheelunits.... Next year,General Motors (GM) willmake much use of on-board microcomputersystems in its vehicles to

Put your applications

to work on the Mostek

STD-Z80 BUS.

You'reready. You'vegone beyond thelearning stage and are using yourpersonal computer to implementreal time control applications.

We can take you one bigstep further. By showing you howto take the programs you havedeveloped using your TRS-80(or other Z80 based computer)and place them in PROM on alow-cost stand-alone micro cardsystem. This will not only free upyour main computer for new ap-plications, but will also permityour current application to be"on-line" continuously,or even"cloned"-for multiple installationsor sales to other users.

Mostek's MD Series of STD-Z80 BUS compatible microcomput-

er cards makes all this possible.There are more than twenty dif-ferent boards in this off-the- shelffamily available now, includingdata processing boards; memoryboards (Static and Dynamic RAM,ROM/PROM); I/O cards; A/D; D/A;high speed floating point math;and floppy disk controller cards.QC Micro Systems offers all

support software and,of course, extensivedocumentation. And much more.Contact us for details so they canbe put to work for you, bysending in the coupon below.Today. QC MicroSystems, P. O.Box 401326,Garland, TX

75040,(214) Sterns343-1282.

of these

1 Yes! I'm ready for more information on the STD-Z80 BUS products from| QC MicroSystems. My application is

□ Personal □ Resale

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□ Yes, I would like to use my TRS-80 as my STD BUS development station.

productsdirectly,includinga full rangeof supportproductssuch asprototypinghardware,

Company

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Circle 84 on inquiry card.

meet the stringent re-quirements for emissionscontrol and fueleconomy. GM's need forelectronic parts will be sogreat that the companywill use 56% of theworld's supply of 8 K-byte read-only memoriesand 40% of the analog-to-digital converters, ac-cording to a GM estimate.In all, GM will buy 13 to15 million electronicparts each day, morethan 3 billion parts peryear.... Chase ManhattanBank is developing thePersonal Computer BankCommunications System.Any bank customer whohas a home terminal orcomputer system will beable to access (viatelephone) his or her ac-count, get an up-to-the-second status report, andcause funds to betransferred. The userwith a computer will alsobe able to do batch-modetransfers and off-lineprocessing of bank ac-count data.... The precur-sor of flat solid-state datadisplays may have ap-peared. Crokroft Interna-tional of Sunnyvalu,California, has introduc-ed a liquid-crystaldisplay (LCD) panel with32-by-32-dot display. Itoperates about four timesfaster than current LCDdisplays. The companyalso expects to have avariable-color display inthe near future.... Forthe first time, amicrocomputer-softwarepackage has been placedon the prestigiousDatamation magazineHonor Roll of SoftwarePackages. Naturally, thesoftware package was theCP/M operating system,a product of DigitalResearch. MicrosoftBASIC and UCSD Pascalreceived honorable men-tion.... A report from In-ternational ResourceDevelopment, a manage-ment consulting firm,predicts that four billiondollars will have beenspent on electronic-mailservices and equipmentby 1990. The field will bedominated by IBM,

AT&T, and GT&E, withthe US Postal Service get-ting about one quarter ofthe business.... A newsupercomputer projecthas been started.Denelcor of Denver, Col-orado, is planning tomanufacture a computerthat uses 50 processors,capable of performing500 million instructionsper second in parallel....Texas Instruments andHitachi are developing64 K-bit programmablememories, which shouldbecome available nextyear....

Wourt Upholds FCCRuling On TI Modulator:

The District of ColumbiaCourt of Appeals has re-jected an appeal by AtariCorporation (see lastmonth's column). Atarichallenged the ruling ofthe Federal Communica-tion Commission (FCC)that allows Texas In-struments (TI) to sell itsstand-alone radio-frequency (RF)modulator while the FCCreexamines its ownguidelines for electronictelevision accessories.Atari argued that the FCCshould have forced TexasInstruments to abide bythe present rules untilchanges became final.The present regulationsprohibit the marketing ofstand-alone modulators.Texas Instruments usesthese modulators with itsModel 99/4 personalcomputer system.

J\adio Shack And AppleAsk FCC For DeadlineExtensions: Tandy Cor-poration (parent com-pany of Radio Shack) andApple Computer Com-pany have filed separatepetitions with the FCC,asking that the FCC'sJuly 1, 1980 deadlinefor compliance with newradiation standards beextended. They feel thatthere could be an adverseeffect on products still indealer stocks, whichcould take 6 to 9 monthsto sell. All units

manufactured after July1 will have to complywith the standards.General Electric, GeneralTelephone and Electronic(GT&E) Services Corpora-tion, Honeywell, ControlData Corporation, Atari,American Telephone andTelegraph (AT&T), theComputer and BusinessEquipment Manufac-turers Association(CBEMA), and ElectronicIndustries Association(EIA) have also filed peti-tions. Most of these peti-tioners asked for a 2-yearextension, while someasked for as many as 7years.

W.

ord-Processing Stan-dard In Development: An

American National Stan-dards Institute (ANSI)Group (number 4 ofX4A12) has completed aworking draft of thepage-image format of aword-processor standard.The purpose is tofacilitate communicationsbetween word processorsfrom different vendors ina common language. Thepresent draft is con-sidered only a first step;the first part of the stan-dard is expected to beadopted by midyear.

M

»icroprocessorTechnology Seen Affect-ing Employment: A

report presented at a re-cent conference of theOrganization forEconomic Cooperationand Development (OECD)in Paris, France, cited animpact on employment inJapan by microcom-puters. The report wasprepared by a specialcommittee organized bythe Japan InformationProcessing DevelopmentCenter and sponsored bythe Ministry of Interna-tional Trade and In-dustry.

The report forecastssubstantial job layoffsdue to labor-savingmicrocomputer-con-trolled equipment. Thebiggest effect will be feltin assembly manufac-

turing where automationwill substantially reducethe number of unskilledworkers on the assemblyline. On the other hand,the report predicted anincreased need forsystems and softwarepersonnel.

M,

•icrocomputer Lip-Reader For Deaf: The

Research Triangle In-stitute in North Carolina,working with funds fromthe National Aeronauticsand Space Administration(NASA) and the VeteransAdministration, isdeveloping a micropro-cessor-based system tohelp the deaf read lips.The device, calledAutocuer, can increase atrained lip-reader's com-prehension from thetypical 25% to about90%. Alight-emittingdiode (LED) display pro-jects representations ofsounds as nine simplepatterns correspondingto the sound.

Vommodore IntroducesNew 4-bit Micropro-cessor: While othersemiconductor makersare going to largermicroprocessors (typical-ly 16-bit or enhanced8-bit devices) Commodorehas decided to go in theother direction. ChuckPeddle, the wizard whocreated the 6502 micro-processor (used in thePET, Apple, Ohio Scien-tific, Atari, and othercomputers) and who alsocreated the KIM-1 andPET computers, has nowturned his efforts todesigning a "super" 4-bitmicroprocessor called theMCS4500. Using com-plementary metal-oxidesemiconductor (CMOS)technology, it has thirty-four instructions, on-board memory (including2 K bytes of read-onlymemory and 176 nybblesof scratch-pad memory),and can directly drive upto four multiplexedliquid-crystal displays(LCDs). Memory can beexpanded, and many of

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Circle 85 on inquiry card.

BYTE May 1980 147

the features found on8-bit processors are in-cluded. Commodore willoffer an assembler andemulator for the devicethat runs on a PETmicrocomputer.

Xeee DevelopingAssembly-Language Stan-dard For Microcom-puters: The Institute ofElectrical and ElectronicsEngineers (IEEE) isdeveloping a standard forassembly language onmicroprocessors (IEEETask P694/D11). It islong overdue and will beof enormous value to allassembly-language pro-grammers who are strug-gling to write code fordifferent micropro-cessors. The group work-ing on the standard hasdone some genuinelyworthwhile things, suchas demonstrating that allthe current major micro-processors can be han-dled by a single stan-dard.

The problems of pre-sent inconsistency are in-credible. For example, inassembly code for someprocessors, MOV A,Bmeans "move the con-tents of register B to A,"while for others it meansjust the opposite.

The new IEEE stan-dard should cure prob-lems such as those thatoccurred when Zilog didnot use the Intelmnemonics for the Z80'sinstructions, which are asuperset of the 8080's in-structions (probablybecause Intel copyrightedthe mnemonics).

The standard alsocovers instructionnames, address modes,operand sequences, ex-pression evaluation, con-stants, labels,comments,and assemblerdirectives. The standarddoes not specify the syn-tax necessary to supportmacroinstructions orconditional assembly.

The IEEE ComputerSociety is to be con-gratulated for its ac-tivities in developingcomputer standards,

which are overcomingproblems created by com-panies that all too oftenintentionally create in-compatibilities to protecttheir competitive posi-tion.

I predict that thisassembly-language stan-dard will meet with thewide adoption that theother IEEE standards(such as the IEEE-488 in-terface and IEEE S-100bus standards) have met.You can obtain a copy ofthe Assembly LanguageStandard draft by send-ing a self-addressed 10by 13 inch (26.4 by 33cm) envelope with $0.54US postage affixed to DrRobert G Stewart, Chair-man of Computer Stan-dards Committee, IEEEComputer Society, 1658Belvoir Dr, Los Altos CA94022.

Incidentally, the IEEEis also working onseveral other standardsrelevant to the microcom-puter area. These pro-jects are: Multibus,Microbus, Futurebus,Floating Point, High-Level Languages, Pascaland Relocatable ObjectFormat. I will try toreport on IEEE's pro-gress in a futureBYTELINES column.

JL elecomputing Com-panies Off To A GoodStart: The Source, atelecomputing serviceprovided by Telecom-puting Corporation ofAmerica (or TCA, head-quartered in McLean,Virginia), is just sixmonths old. The Sourcehas 3000 subscribers andis adding 500 more perweek. The company,which provides informa-tion retrieval and soft-ware services via atelephone network, hasgrown to thirty-fiveemployees and a monthlyrevenue of $100,000. TCAis aiming to have100,000 customers bythe end of 1980.

A competing servicecalled MicroNet, providedby CompuServe Incor-porated of Columbus,

Ohio, is aimed more atthe hobbyist. They claimto have 1200 customersalready. However, thereis a dark cloud on thehorizon, in the form ofthe Teletext andViewdata systems nowbeing tested by GT&E,Texas Instruments, andothers. This may providemuch lower cost but lessflexible data access to thehome television screen.

J» lat CRT Unveiled AtCES: Sinclair Radionicsdemonstrated a prototypeof their flat-screencathode-ray tube (CRT) atthe Consumer ElectronicsShow (CES) held inJanuary. Sinclair hopesto use it in a $125 televi-sion receiver to beavailable in late 1981.The electron gun ismounted sideways, withthe beam deflected tostrike the phosphor-coated screen. The imageis brighter than imageson conventional CRTs.The entire receiver willmeasure 2.5 by 10.2 by12.7 cm (1 by 4 by 5inches). The company isdoing additional researchto develop large-screenand color flat CRTs.

Xlandom Rumors: Cen-tronics, the largest sup-plier of printers today,will soon cut prices 20 to30% on existing low-costprinters and will unveilnew products directedspecifically at the per-sonal computer market,including both impactand nonimpact serialmatrix units....Dataproducts, Okidata,and a number ofJapanese manufacturersincluding NEC arerumored working onmultipass, high-density,dot-matrix printers tocompete with the RCSanders TechnologySystems Media 12/7.printer. However, at pre-sent Sanders Technologyhas about a 2-year leadtime on thistechnology.... RadioShack might introduce

more than one new per-sonal computer system inthe late fall (see theFebruary 1980 columnfor previous rumors)....Reports have been cir-culating that DataGeneral is developing adesk-top computer, code-named Wing. It will use amicroprocessor, have twofloppy-disk drives, andwill be made inTaiwan.... It is rumoredthat Toshiba ElectricCompany is working onan experimental voice-input typewriter. Theunit will be able to type100,000 to 200,000 dif-ferent words in Japaneseand will recognize wordswith 90% accuracy.Toshiba recentlydemonstrated prototypevoice-activated televisionand high-fidelity equip-ment. ... More rumors aresurfacing regarding thefuture plans of AppleComputer Company.Reportedly the newmodel Apple computerwill be a Pascal machinefor educational users.Also, Apple will place in-creased emphasis on thebusiness market....

wongress ConsideringTwo Personal ComputerBills: Did you know thattwo bills about personalcomputers have been in-troduced in Congress?One is H.R.3822, whichwould set up a nationalendowment for personalcomputers. The other isH.R.4326, which wouldcreate a presidential com-mission to make recom-mendations about thepersonal computer field.

MAIL: I receive a largenumber of letters eachmonth as a result of thiscolumn. If you wish aresponse, please include astamped, self-addressedenvelope.

Sol Libes

Amateur Computer

Group of New Jersey

(ACG-NJ)

1776 Raritan Rd

Scotch Plains NJ

07076

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HEURISTICS SPEECHLINK 2000 225"

WE SELL APPLE SOFTWARE ALSO.

DC HAYES MICROMODEM II t335"°

ALF MUSIC SYNTHISIZER 245"

SSM A10 CARD (KIT) 125"

SSM A10 CARD (A»T) 190"

NOVATION CAT MODE M 169"

SUP-R-MOD RF TV MODULATOR 25.00

SUP-R-TERM 80 col. CARD 349"

DAN PAYMAR lower case kit 45.00

SVA 8" DISK CONTROLLER CARD 349"

CCS ARITHMETIC PROCESSOR CARD .. 349.00

CCS GPIB INTERFACE CARD 269.00

CONTROLLER Gen, Bus. software 529"

CASHIER Retail Mangmnt. & Invert, soft... 209"

APPLE POST Mailing List software 45"

APPLEWRITER Word Proceaalng aoftware . 69"

ATARI 400 COMPUTER $499.00

ATARI 820 PRINTER $499.00

ATARI 810 DISK DRIVE $599.00

ATARI 410 PROGRAM RECORDER $69.00

ATAR116K RAM MODULE $149.00

•High resolution COLOR Graphics•1 OK Basic in ROM•8K user RAM expandable to 48K•57 key full stroke keyboard

• Built-in RF TV modulator•High speed serial I/O port

• Includes ATARI 410 program recorderWE SELL ATARI SOFTWARE ALSO.

THE AMAZING

SORCERER

The SORCERER is a Z80 CPU bcsedmi.iblt?'o48K 4K ROM resident monitor ID.ir'sion P;iiai>!>i,itici serial interface Du;rasolui-ono. 240 x 512 30linesot64charaei■naifi* Full ASCII sei (upper and lower casei piusstnnd,

gfaOrVC iyfllbOlS User may Qeline up !Doaro fi 63*ey daia processing type

MK 1,2*3.00

OHIO SCIENTIFIC

CHALLENGER

4p$649

•8K BASIC in ROM

■8K Ram expandable to 32K

•16 COLOR GRAPHICS

Featuring

• 32x64 Upper & Lower case characters•256 x 512 High resolution graphic points•Programmable tone generator 20hz • 20KHz

• Plus more!

CHALLENGER C4PMF$1589

All the features of the C4P plus ...

•A SINGLE MINI FLOPPY DISK DRIVE

•A REAL TIME CLOCK

•SECURITY SYSTEM, MODEM 8, PRINTER INTERFACE

• 24K RAM expandable to 4SK (of reliable static RAM)

WE SELL OSI ACCESSORIES A SOFTWARE ALSO.

TexasInstruments

TI-99 4 979

•16K of user RAM•Extended BASIC language in ROM•16 COLOR GRAPHICS•Supported with Solid State Software

INCLUDES a 13 inch COLOR VIDEO MONITOR

We sell TI-99/4 Accessories & Software Too.

MICROPOLIS

1021 mod ii "VSaurT. >S29'

1041 MOD II """ISxr" 899

1043 mod ii —tssssr* 999'

1053 MOD II """SSSSr* 1649'

•315K Bytes storage per drive•QUAD DENSITY DESIGN•COST EFFECTIVE STORAGE•4 TIMES STANDARD CAPACITY!

MetaFloppy

DRIVES

SOROCIQ120

SERIAL RS232C

FULL ASCI I UPPER/LOWERCASENUMERIC KEYPAD CURSER KEYSSCREEN CONTROLS *.PROTECTED FIELDS *

739

•ALSO AVAILABLE-

SOROC IQ 140 *119500

These terminals are shipped freight collect only.

MONITORS

LEEDEX VIDEO 100

12" BLACK & WHITE MONITOR

•VIDEO BANDWIDTH 1 2 MHz±3db• COMPOSITE VIDEO INPUT

•13500

SANYO 9" Black & White Monitor. $169SANYO 1 5" Black & White Monitor. 259

ZENITH 13" Color Monitor 399

PRINTERS

PAPER TIGER ITS 440 875

With Graphics Option 1,075

CENTRONICS 730-1 850

CENTRONICS 779-1 1,049

ANADEX DP-8000 850

AXIOM EX-801 495

AXIOM EX-820 795

COMPRINT 91 2S 599

COMPRINT 91 2P 559

TRENDCOM T-1 00 349

. TO ORDER .

Phone orders invited, using credit cards. Or send cashierscheck or money order that draws on a U.S. bank. Please add3% ($5 00 Minimum) tor handling, shipping (air service) andinsurance, or equipment will be shipped freight collect.California residents add 6% sales tax. All equipment is infactory cartons with the manufacturers warranty Equipmentis subject to price change and availability without notice .

6363 EL CAJON BLVD., SUITE 105,SAN DIECO, CA. 92115 • (714) 579-0330

Circle 86 on inquiry card.

BYTE May 1980

149

NEECO

Microcomputer Systems Division

PROUDLY ANNOUNCES THE NEWEST

iRDWARE AND SOFTWARE FOR YOUR PET!

The PET is now a truly sophisticated

Business System with the announcement

of these peripherals and software packages.

.<$

4h&

3EK

<>*

NEWNEW

NEW

PRODUCT DESCRIPTION

PET 2001— 8KN 'Large Keys) 8K RAMPET 2001— 8K 8K RAM

PET 2001—16KN (Large Keys)16K RAM*PET 2001—32KN (Large Keys)32K RAMPET 2023 PRINTER ROLL FEED

PET 2022 PRINTER TRACTOR/ROLLROMRETRO KIT UPDATED O/S

PET 2040 DUAL FLOPPY*

PET C2N 2nd Cassette

'The 16K/32K (large keyboard) units do not include a cassette drive. Order C2N Cassette.2040 Floppy Drive requires a 16K or 32K unit. 8K RAM Retrofit available July.

ALL PETS ARE FULLY TESTED BY NEECO BEFORE SHIPMENT. NEECO IS A FULLCUSTOMER-ORIENTED COMPANY. CALL FOR OUR FREE CATALOG. ALL ORDERSOVER $795 WILL RECEIVE A FREE NEECO PET DUST COVER AND $100 OF SOFT-WARE FROM OUR CATALOG IF YOU MENTION YOU SAW THIS AD.

PRICE

AVAILABILITY

$ 795

IMMEDIATE

$ 795

IMMEDIATE

$ 995

IMMEDIATE

$1295

IMMEDIATE

$ 695

IMMEDIATE

$ 795

IMMEDIATE

$ 90

IMMEDIATE

$1295

IMMEDIATE

$ 95

IMMEDIATE

EDUCATORS TAKE NOTICE !

2 Commodore KI^^IA/ —Computers INvJVV —

3 CommodoreComputers

/At least until \15th, 1980^

^Aug.

Neeco is pleased to announce a Special Educational Program from Commodore BusinessMachines. Any bona fide school or educational institution will receive one CBM/PETComputer absolutely * Free • (direct from Commodore) for every two CBM/PET Com-puters Purchased at retail!

Contact NEECO for details and ordering information

EDUCATORS TAKE NOTICE !

PRODUCTS ARE AVAILABLE TO DEALERS VIA MICROAMERICA DISTRIBUTING (617-449-4310)

FOR WORD PROCESSINGNEC IS BEST!

* 55 characters per second output speed

* Changeable thimble for different typestyles

* Less than 1% warranty malfunction rate

* IBM quality letter output

* Dealer inquiries invited

THE NEC SPINWRITERMODEL 5530-P ( SSffifWSrr)

$2995

"Price includes IEEE interfaceto PET. IEEE Port is availablefor use with 2040 Dual Disk.

'The NEC 5530-P is the output printer recommended by Commodore for their Word Processing System.

KJCCTf^^ Mon-Fri 9:30-5:30IMIZCV-f \J MasterCharge &

679 Highland Ave. Visa Accepted

(617)449-1760

Telex: 951021

Needham, MA02194

MICBOAMERICA DISTRIBUTING

"Nationwide distributors of Computer Equipment"21 Putnam StreetNeedham, MA

Q2194 (617) 449-4310

Circle 88 for NEECO

Circle 87 for microamerica

NEECO

PROUDLY

INTRODUCES

MULTI-CLUSTER

"Multi User Management System forCommodore CBM/PET* Computers"

UP TO 8 CBM/PETS MAY NOW SIMULTANEOUSLY ACCESS ONE 2040!

Channel ModuleCM-800

Multi-Cluster

Model MC-800A

Standard 3 Channels)

$995

Up to 8 Channel (3 Standard) for CBM/PET Computers.Up to 8 CBM/PETS can multi-use one Commodore 2040dual disk drive simultaneously with equal access.Multi-Cluster supports all 2040 disk O/S commandsincluding sequential, random access, and user files.Multi-Cluster does not utilize any RAM or ROM from the2040 or host CBM/PET units.

Multi-Cluster is compatible with all known softwear thatutilize the IEEE port.

Multi-Cluster can be fully implemented on 8 PETS,completely ready to use, in less than 15 minutes.Simply plug the Multi-Cluster unit into the IEEE port ofthe 2040 Disk Drive, then attach a Channel Module,#CM800, (3 Channel Modules are standard with unit), to theIEEE port of each PET.

THE MULTI-CLUSTER SYSTEM HAS BEEN USED AND FULLY-TESTED BY NEECO

Multi-Cluster

Model MC-800A

(Standard 3 Channels)

/

N

K

Up to 8

CBM/PETS

May Access

One 2040

Disk Drive

? Jgjk

IBBBiiSfiMMlt fflil

X

<

OptionalOutputPrinterModule

>

j

BMSflMMfr 1B1\

Multi-Cluster is ideal for industrial, OEM, VerticalMarkets, and Educational Institutions. Multi-Cluster allows you to make full use of the Com-modore 3 units for the price of 2 educational pro-grams.

Standard Components:

1 Multi-Cluster #MC800A

3 Channel Modules #CM-100

3 6' Ribbon Cables #RC6

Output Printer Module allows1 CBM/PET to scan 2040 Diskand print flagged files.

Optional Component Prices:

Each additional CM-100 $250

Each 12' Ribbon Cable (RC12) $ 40

Each 18' Ribbon Cable (RC18) $ 60

Output Printer Module (PM200) $200

(For Centronics Protocal Printers)

*PET is a registered trademark of Commodore Business Machines. Small Keyboard PETS require a ROM Retrofit Kit for Multi-Cluster system operation.Multi-Cluster is available in Canada from BMB Compu Science, Milton, Ontario, (416) 878-7277

NEECO

679 Highland AveNeedham, MA02194

Dealer Sales:Microamerica Distributing

21 Putnum St., Needham, MA 02194(617)449-4310 Telex: 951021

Customer Sales:NEECO

679 Highland Ave.,(617)449-1760

Needham, MA 02194

Circle 90 for NEECO

Circle 89 for microamerica

Technical Fcnum

Simplifying the Curve-Plotting Calculation byGeometric Means

A David Nawrocki, 1101 Wiltshire, San Antonio TX 78209

I enjoyed reading Timothy G Bowker's interesting arti-cle "Minimizing Curve-Plotting Calculation" (December1979 BYTE, page 134). Perhaps it is worth pointing outthat his equation (1) on page 138, which involves arc-tangent and cosine functions, can be reduced to a moreefficient form for computational purposes. Although theimprovement is slight, the use of a single square-rootterm will allow more rapid calculation than thetrigonometric functions originally used. If a very largenumber of points must be plotted, the accumulated sav-ings in time can be significant.

First, let us note from the illustration in figure 1 that hisAx5 (the quantity to be found) is related by similar

Kill SurgesLike Lightning!

Surge Sentry 120 works in parallel with the powerline to shunt destructive power surges in less than1 nanosecond! Triggers at 10% above the nominalpeak voltage. Plugs into any standard 120-voltoutlet for immediate protection.

Ideal for small computers, communications,medical, and other sensitive electronic equipment.Suggested retail price $89.50. OEM model alsoavailable. Call or write:

;] [< 5 R&K Enterprises

643 South 6th Street, San Jose, CA 95112(408) 288-5565.

Dealer inquiries invited.

CURVE BEING PL0TTED-

L

5i_i. L

SEQUENCE OF

CALCULATED

POINTS:

^ ■»«».»*'

^■-P6 = U6.»6>

triangles (I and II) to Ax4, Ay4, and L (quantities knownfrom previous steps) as follows:

Ax5 = L Ax4

VAxT+TXyl

The possible scale factors M and N cancel out, and it isnot necessary to compute Q4 to obtain Axs.B

Alpha Lockingin Software

W S Lewis, POB 1555, East Canton OH 44730

Those readers of BYTE who are not hardware fanaticscan accomplish the same results in software as wasobtained by use of hardware in Terry Conboy's article"Alpha Lock for Your ASCII Keyboard" (January 1980BYTE, page 156). You can let your computer do thework!

In particular, users of the Z80 microprocessor can add8 bytes of code to the keyboard-input subroutine. Thecode shown here as listing 1 should appear in the input

Listing 1: Portion of Z80 code for uppercase to lowercase con-version, input section.

HexadecimalObject Code

DB 30CB 4F28 FADB 31CB BF

InstructionMnemonics

XIN IN A,(30H)BIT 1 ,AJR Z.XININA,(31H)RES 7,A

Comments

; STATUS PORT

; KEYBOARD;MASK PARITY

Listing 2: Final portion of Z80 code for uppercase to lowercaseconversion.

HexadecimalObject Code

FE61

F8

FE7B

F0

D6 20

C9

InstructionMnemonics

CP61H

RETM

CP7BH

RETP

SUB 20H

RET

152 May 1980 © BYTE Publications In

Circle 91 on inquiry card.

YOUNG AND BRILLI

1

'W.

Every so often an individual is born exhibiting extraordi-nary talent at a very early age. Often, they rise above themultitude establishing themselves as masters in their fields.These individuals are called prodigies.

The Prodigy computer is so advanced, it clearly estab-lishes itself as a master in the field of small businesscomputing.

Modular design and single board construction mean reli-ability, expandability, and ease of service.

But it is SOFTWARE which truly sets Prodigy apart. Un-like other computers, software was a majordesignconsider-ation rather than an afterthought. Prodigy utilizes a highlyadvanced operating system and PROTEGE* to providesome very impressive features:

■ DATA BASE MANAGEMENT ■ INDEXED FILES

■ VIRTUAL CODE ■ SPOOLING

■ DATA COMPRESSION ■ MULTI-TASKING

The result? Incredible speed and storage capacity, andeconomical systems development and maintenance.

Ilt^t: '''■

. . . "Though it may look like many other microcom-puter systems . .. Prodigy One literally speeds awayfrom them ..." — Max Schindler, Software Editor-ELECTRONIC DESIGN.

Your local Prodigy dealer maintains an extensive libraryof field proven application software. Available applicationsinclude General Ledger, Accounts Receivable, AccountsPayable, Payroll, Medical Billing, and a remarkable systemfor the Personnel Placement Industry. All are easy to use yetprovide a level of sophistication unheard of in its price class.And Prodigy also does word processing!

Prodigy systems are supported by a nationwide organiza-tion of thoroughly trained, experienced professionals. YourProdigy dealer is a SINGLE source for hardware, softwareand a level of service that continually insures effective, trou-ble free operation.

Speed, sophistication, and low cost; an incredible combi-nation for a small business computer. Would you expectless from a PRODIGY?

SYSTEMS, INC.

497 LINCOLN HIGHWAY • ISELIN, N.J. 08830 • (201) 283-2000

'Prodigy's easy to use compiler-based small business applications development language. Prodigy also supports other popular languages such as FORTRAN, COBOL, BASIC, and PASCAL.Circle 92 on inquiry card. BYTE May 1980 153

The

Working

Analyst.

If you would like to puta computer to workcollecting, organizing,and summarizingthe informationyou need to makebetter decisions, takea look at Analyst.Analyst is a softwarepackage designed to letyou store and analyzevirtually any informationinvolving numbers, dollars,dates, and descriptions. Simplytell Analyst what kind of informa-tion you want to store. Analyst creates a com-puterized file for that information. And Analystcreates an information entry program for yourfile that asks you for each entry, and checks yourdata for errors. (You can create any number ofdifferent files.)

Then tell Analyst what reports you want fromyour data file. There are all sorts of recordselection and report formatting options, so youcan design an unlimited variety of reports tofocus on different aspects of the same data file.

Analyst is so flexible, you'll find a millionways to use it. It is easy to use, so you don't needto be a programmer to makeyour computer reallywork for you. If this bitof informationintrigues you, find outthe rest. You'll likewhat you see.

Analyst is a part of a full line of working software solutions fromStructured Systems Group, all ready to run on any CP/M* microcomputersystem. For more information, see your computer retailer, or call us.

'CP/M is a trademark of Digital Research.

Structured Systems

5204 Claremont Oakland, Ca. 94618 (415) 547-1567

subroutine. The code in listing 2 goes at the end of the in-put subroutine, just before it returns to its calling routine.Note that the uppercase option is completely undersoftware control. The first compare-immediate (the CP61H) instruction in listing 2 can be changed to a return(RET) instruction when lowercase is desired, and restoredto CP when uppercase is desired. ■

Maintaining a SingleExit Point

Armond Inselberg, 234 Central Ave, Mountain View CA 94040

I agree with James Lewis, author of "Some Notes onModular Assembly Programming" (December 1979BYTE, page 222), in his emphasis on modular program-ming. However, another important tenet of structuredprogramming is the use of a single entry point and asingle exit point for a given program module.

The ABORT routine in the modular 8080 code exampleof listing 2 (on page 224) violates this principle of havingonly one exit point. In this case we find that the ABORTroutine can be exited by either the JNZ (ie: jump if accu-mulator is not equal to 0) instruction or by the RET(return from subroutine) instruction.

To apply the single-exit principle to the ABORT rou-tine, we must arrange things such that the RET instruc-tion causes a return either to the monitor or to the mainlevel of the application code. To return to the monitor us-ing RET, we must replace the current return address onthe stack with the entry-point address for the monitor.

The top of the stack can be changed with the XTHLinstruction, which exchanges the contents of the H and Lregisters with the top of the stack. The ABORT routinewould then be coded:

ABORT

RETURN

LDA SHKEY

ORAA

JZ RETURN

LXI H,MONITOR

XTHL

RET

;no shift key request;shift key hit;exchange stack and HL

However, my preference is that the return to themonitor never be made at all from the ABORT routine,since ABORT is nested below the main level of code. Iwould rather proceed as follows.

First, in ABORT, test for the conditions requiring amonitor return, and set up the stack (if necessary) for thereturn to the monitor. Then, ABORT should set a signalrequesting a return to the monitor, and then just return tothe main level of the application code. At the main level,either a return to the monitor or a jump to the startingpoint of the application would be made.

The main level would then be coded:

START

CALL RANDOMCALL NOTECALL ABORTJZ STARTRET

no monitor requestmonitor return requested.

154 May 1980 © BYTE Publications Inc

Circle 93 on inquiry card.

SuperSof t announces a complete line ofCP/M compatible software

ACCOUNTING

SuperSott offers a complete, interactive accounting system at an affordableprice. We started with the Osborne accounting system, the standard of theindustry, and made it even better. Since either the General Ledger and theAccounts Payable/Receivable can stand alone, you do not need to purchase theentire system at once. This means that you can start with what you need andup-grade later. Look for a compatible Payroll package in the future.

ACCOUNTS PAYABLE/RECEIVABLE: A complete, user oriented packagewhich features:

automatic postings to general ledger (optional)

accounts payable: • check printing with invoice • invoice aging

accounts receivable: • progress billing • customer statements

• partial invoice payments • invoice agingThe entire package is menu driven and easy to learn and use. It incorporates errorchecking and excellent user displays. This package can be used stand alone orwith the General Ledger below. Requires: 48K CP/M, terminal with cursorpositioning and clear screen,one 8" disk or Two 5" disks.CBASIC2 required.

Supplied with extensive user manual: $200.00. Manual alone: $20.00.

GENERAL LEDGER: A complete, user oriented package which features:

• Accepts postings from external programs (i.e. AP/AR above)

• Accepts directly entered postings

• Maintains account balances for current month, quarter, and year and previousthree quarters

• Financial reports: trial balance, income statement balance sheet, and more.Completely menu driven and easy to learn and use. Excellent displays and errorchecking for trouble free operation. Can be used stand alone or with AccountsPayable/Receivable above. Minimal requirements: 48K CP/M, terminal withcursor positioning, home and clear screen, one 8" disk or Two 5" disks.CBASIC2 required.

Supplied with extensive user manual: $200.00. Manual alone: $20.00.

TEXT PROCESSING

-SYSTEM MAINTENANCE

TFS-Text Formatting System:

than 50 commands. Features include:

• left 8 right margin justification

• headers and footers

• page numbering

• chaptering

• dynamic insertion from disk file

• exdented & indented paragraphs

• works with any printer or CRT

An extremely powerful formatter. More

• tabbing

• auto paragraphing

• auto list numbering

• centering

• user defined macros

• underlining and backspace

• much, much more

TFS lets you make multiple copies of any text. For example: Personalized formletters complete with name & address & other insertions from a disk file. Text isnot limited to the size of RAM making TFS perfect for reports, manuals or any bigjob.

Text is entered using CP/M standard editor or most any CP/M compatibleeditor. TFS will link completely with Super-M-List making personalized formletters easy.

Requires: 24K CP/M.

Supplied with extensive user manual: $85.00. Manual alone: $20.00.

Source to TFS in 8080 assembler (can be assembled using standard CP/Massembler) plus user manual: $250.00.

MAILING LIST

SUPER-M-LIST: A complete, easy to use mailing list program package.Allows for two names, two address, city, state, zip and a three digit code field foradded flexibility. Super-M-List can sort on any field and produce mailing labelsdirect to printer or disk file for later printing or use by other programs. Super-M-List is the perfect companion to TFS. Handles 1981 Zip Codes!

Requires: 24K CP/M.

Supplied with complete user manual: $75.00. Manual alone: $10.00

UTILITIES

Utility pack #1: A collection of programs that you will find useful and maybe

even necessary in your daily work (we did!). Includes

CMP: Compare two files for equality.ARCHIVER: Compacts many files into one. useful when you run out of directoryentries.SORT: In core sort of variable length records.XOIR: Extended, alphabetical directory listing with groupings by common

extension.PRINT: Formatted listings to printer.PG: Lists files to CRT a page at a time... plus more...Requires: 24K CP/M.Supplied with instructions on discette: $50.00. FJfSt in Sof tW3re Technology

SuperSoft

DIAGNOSTICS I: Easily the most comprehensive set of CP/M compatiblesystem check-out programs ever assembled. Finds hardware errors in yoursystem, confirms suspicions, or just gives your system a clean bill of health.

TgSiS'

• Memory • CPU (8080/8085/Z80) • Terminal

• Disk • Printer

To our knowledge the CPU test is the first of its kind anywhere. Diagnostics I canhelp you find problems before they become serious. A good set of diagnosticroutines are a must in any program library.

Minimal requirements: 24K CP/M. Supplied with complete user manual:$50.00 Manual alone: $15.00.

SOFTWARE SECURITY

ENCODE/DECODE: A complete software security system for CP/M. Encode/Decode is a sophisticated coding program package which transforms data storedon disk into coded text which is completely unrecognizable. Encode/Decodesupports multiple security levels and passwords. A user defined combination(One billion possible) is used to code and decode a file. Uses are unlimited. Beloware a few examples:

• data bases • general ledger • inventory

• payroll files • correspondence • accounts pay/rec

• programs • tax records • mailing listsEncode/Decode is available in two versions:

Encode/Decode I provides a level of security suitable for normal use.Encode/Decode II provides enhanced security for the most demanding needs.Both versions come supplied on discette and with a complete user manual.

Encode/Decode I: $50.00

Encode/Decode II: $100.00 Manual alone: $15.00

PROGRAMMING LANGUAGES

ENHANCED 'TINY' PASCAL: We still call it 'Tiny' but it's bigger and betterthan ever! This is the Famous Chung/Yuen 'Tiny' Pascal with more featuresadded. Features include:■ recursive procedures/functions • integer arithmetic • CASE

• FOR (loop) -sequential disk I/O • one dimensional arrays■IF... THEN... ELSE -WHILE • 'PEAK' & 'POKE'

• READ & WRITE -REPEAT ... UNTIL -more

'Tiny' Pascal is fast. Programs execute up to ten times faster than similar BASICprograms.

SOURCE TOO! We still distribute source, in 'Tiny' Pascal, on each discettesold. You can even recompile the compiler, add features or just gain insight intocompiler construction.

'Tiny' Pascal is perfect for writing text processors, real time control systems,virtually any application which requires high speed. Requires: 36K CP/M. Suppliedwith complete user manual and source on discette: $85.00.

Manual alone: $10.00.

—INTERCOMPUTER COMMUNICATIONS

TERM: a complete intercommunications package for linking your computer toother computers. Link either to other CP/M computers or to large timesharingsystems. TERM is comparable to other systems but costs less, delivers more andsource is provided on discette!

With TERM you can send and receive ASCII and Hex files (COM too, withincluded convertion program) with any other CP/M computer which has TERM orcompatible package. Allows real time communication between users on separatesystems as well as acting as timesharing terminal.

• Engage/disengage printer • error checking and auto retry

• terminal mode for timesharing between systems • conversational mode

• send files ■ receive filesRequires: 32K CP/M.

Supplied with user manual and 8080 source code: $100.00

Manual alone: $15.00.

formats: CP/M 8" SOFT SECTORED. NORTHSTAR CP/M

All Orders and General Information:

SUPERSOFT ASSOCIATES

P.O. BOX 1628

CHAMPAIGN.IL 61820

(217)344-7596Technical Hot Line: (217) 384-0847{answered only when technician Is available)

CP/M REGISTERED TRADEMARK DIGITAL RESEARCH

Circle 94 on Inquiry card.

BYTE May 1980 155

■canpuTHQWicsi

EVERYTHING FOR YOUR TRS-80 •••

TRS HO Is a trademark of ih<- Radio Shack Division of Tandy Corporation

•k All Orders processed within 24-Hours

• Free Shipping within U.P.S. areas (add $3 for orders outside of the U.S.A. or U.P.S. areas).■k 30-Day Money Back Guarantee on all Software (less a $3 penalty for handling).

•k 10-Day Money Back Guarantee on Disk Drives and Printers PLUS 120-Days Free Service.

LEARNING LEVEL II by David Lien

The Original Author 01 The Level ManualA Step By Step approach to Learning Level IIespecially geared to new TRS-80'" Owners$15 95

TRS-80 DISK AND OTHER MYSTERIES

$19.95 ($22.95 alter 2/1/80). Over 100 pages

of indespensible information for disk ownersLearn to recover information from bad disks,how to make Basic programs unlistable and 12more chapters of never published tips and infor-mation Written by H C Pennington (For allDisk Owners)

NEW SBSG BUSINESS SYSTEM FORMODEL I OR MODEL II - IN STOCK

- General Ledger

- Accounts Receivable

- Accounts Payable

- Payroll

- Inventory Control With Invoicing

• Each module can be operated individuallyor as a coordinated SYSTEM. Turn-Key errorcatching operation for beginners

• Complete manual and documentationaccompany each program

• Minimum System requirements 2-DiskDrives for Model l...1-Disk Drive for Model II

• Each module can be formatted to span dataon Upto 4-Disk Drives

• Free 30-Day telephone consultation

• Call for complete specifications

• Model I Version $125 per module$495 per System

• Model II Version $225 per module$995 per System

DATA MANAGEMENT SYSTEMS

- DMS replace index cards or any datarequiring long lists of information.

• TBS In-Memory Information System

(for cassette systems) $24.50

• TBS Disk Data Manager (requires 1 or moredisk drives)...Set up fast random accessfiles in minutes. Stores up to 320K ofinformation on 4 Drives. Up to 10 fieldsand 255 characters per record. Supportsupper and lower case RS-232 or TRS-232...Features complete editing $49.50

• Personal Software CCA Data ManagementSystem...Completely user oriented, menudrive, 130 page Step by Step Manual...capable of inventory control, sorting data,reporting data in nearly any form (for reportsand mailing labels). Sorts data by up to 10fields for zip code, balance due, geographiclocation or whatever. Prints reports withsubtotals and totals automatically calculated.Fast random access $75.00

iCQMRJTRQNICS

NMfMaMUmCAfc Aff^jcjmose stove*""

Box 149 New City, New York 10956

FROM RACET COMPUTES

• REMODEL-PROLOAD - Renumbers pro-gram lines, combines programs The only re-number program that will renumber the middleof a program Specify 16K. 32K or 4BK Workswith Cassette or Disk . . . $34.95

• GSF - Use in your Basic Programs tor InstantSorting (will sort 1000 items in 9 seconds) Othercommands include Compress and UncompressData. Duplicate Memory. Display ScreenControls and Fast Graphic Controls . . . $24.95(For Cassette or Disk, specify 16K. 32K or 48K)

• DOSORT - All G S F commands plus specialMultiple Disk Sorting Routines . . . $34.95(Specify 32K or 48K)

• INFINITE BASIC - Adds 70 commands toyour TRS-80 including Instant Sort, MatrixCommands. String Commands. Lett and RightJustification. String Centering. SimultaneousEquations. Upper and Lower Case Reverse andmore . . . $49.95 (For Cassette or Disk)

• INFINITE BUSINESS (Requires Infinite Basic) -Eliminate Round-off error. 127-Digit Calcula-tion Accuracy. Insert New Elements in SortedArrays. Automatic Page Headings. Footings,and Pagination, Multiple Precision Arithmeticand more . . . $29.95. (For Cassette or Disk).

• COPSYS - Copy Machine LanguagePrograms . . . $14.95 (For Cassette only)

FROM SMALL SYSTEM SOFTWARE

• RSM-2 Machine Language Monitor . .. $26.95

• RSM-2D Disk Version of RSM-2 . . . $29.95

• DCV-1 Converts Machine Language Programsfrom tape to disk . . . $9.95

• AIR RAID - The ultimate TRS-80 game con-verts your TRS-80 into a real time shootinggallery . . . $14.95

• BARRICADE - A fast pong style game.. $14.95

• CPM - $150 (for Disk only)

• TRS-232 INTERFACE - Interface with Soft-ware driver RS-232 printers to your

TRS-80 . . . $49.95

• TRS-232 FORMATTER Additional(optional) Software tor TRS-232 owners Adsmany printer commands to your

TRS-80 . . . $14.95 ($9 95 with purchase ofTRS-232)

MAIL PAC - For Model I or Model II DiskSystems only . . . $99.95. Quick-sorting full usercontrol over mailing list from Gallactic Software

FROM ADVENTURELAND INTERNATIONAL

• ADVENTURE #1 - #8 by Scott Adams .$14.95 each available on Cassette or Disk

SARGON II

THE CHESS CHAMP

$29.95

FROM APPARATNEW DOS ♦ $99.95

35, 40 and 77 Track Versions available

48-Page Catalog $2 FREE With Any Order

Order by Phone or Mail

No Shipping Charge

Add $3 for COD.

Add $3 for all Foreign and non-UPS shipments

Add $3 for UPS Blue Label

FROM HOWE SOFTWARE

MON-3 - Machine Language Programming forBeginners. MON-3 is a CompleteSystem Monitor with UsersManual . . $39.95

MON-4 - Disk Version of MON-3 . . . $49.95

FROM THE BOTTOM SHELF

• CHECKBOOK II (for Cassette or Disk) . .$18.50

• INFORMATION SYSTEM (for Cassette orDisk . . . $24.50

• SYSTEM DOCTOR (a complete diagnosis ofyour TRS-80 checks memory, video, cassette.disk. ROM and all other parts of your system) -for Cassette or Disk . . . $28.50

• CHECKBOOK REGISTER ACCOUNT-ING SYSTEM (requires 2 disk drives).. $49.50

• LIBRARY 100 - 100 established business,game and educational programs plus FREE TinyPilot all for . . . $49.50

• BASIC TOOL KIT - lists all variables. GOTOsand GOSUB's in your program . . . $19.80

SOUNDWARE - Ads sound to your TRS-80.

Just plus it in . . .$29.95. Sample programs

included

TING TONG - Can be used with Soundware

for a Sound version of pong . . . $9.95.

VIC-The Carta Visual Instructional $1995Computer Program

The Level II 16K Cassette is designed to teach

beginners the Basics of Machine Language and

Assembly Language Programming See every

Machine Language Instruction Display on

your.Video

VIC includes a Step By Step 55 page manual

VISTA V80 DISK DRIVE

110 K OF STORAGE

$395

Add $29.95 for Cable

(Free with Purchase of Two Disk Drives)

— 10 Day Money Back Guarantee —

LEVEL III BASIC . . . $49.95 FROMMICROSOFT - Now Cassette owners can addDisk Commands to their TRS-80 without owninga Disk Drive

BRAND NEW OLIVETTI PRINTER . . .$2495

Business Letter quality print, Automatic LineJustification (on request). Quick Printing, canbe used as a Memory Typewriter, plugs rightinto your TRS-80 without any modification orsoftware

THE ELECTRIC PENCIL

Cassette . . . $99.95

Disk . . . $150.00

HORSE SELECTOR II by Dr Hal Davis$50. The TRS-80 version updated for the TRS-80and originally reviewed in Systems andMethods

24

HOUR ORDER LINE

(914) 425-1535

™»SW cfiarge

156 BYTE May 1980

Circle 75 on inquiry card.

THE ORIGINAL MAGAZINE FOROWNERS OF THE TRS-80™* MICROCOMPUTER

SOFTWARE

FOR TRS-80"

OWNERS

H

CQMPJTRQNICS

MONTHLY NEWSMAGAZINE

Practical Support For Model I & II

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PRACTICAL APPLICATIONSBUSINESS

GAMBLING • GAMESEDUCATIONPERSONAL FINANCEBEGINNER'S CORNERNEW PRODUCTSSOFTWARE EXCHANGEMARKET PLACEQUESTIONS AND ANSWERSPROGRAM PRINTOUTS AND MORE

PROGRAMS AND ARTICLES PUBLISHED IN OUR FIRST 12 ISSUESINCLUDE THE FOLLOWING:

A COMPLETE INCOME TAX PROGRAM (LONG AND SHORT FORM)

INVENTORY CONTROL

STOCK MARKET ANALYSIS

WORD PROCESSING PROGRAM (FOR DISK OR CASSETTE)

LOWER CASE MODIFICATION FOR YOUR VIDEO MONITOR OR PRINTER

PAYROLL (FEDERAL TAX WITHHOLDING PROGRAM)

EXTEND 16 DIGIT ACCURACY TO TRS-80'" FUNCTIONS (SUCH AS

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NEW DISK DRIVES FOR YOUR TRS-80"

PRINTER OPTIONS AVAILABLE FOR YOUR TRS-80'"

A HORSE SELECTION SYSTEM***AR1THMETIC TEACHER

COMPLETE MAILING LIST PROGRAMS (BOTH FOR DISK OR CASSETTE

SEQUENTIAL AND RANDOM ACCESS)

RANDOM SAMPLING***BAR GRAPH

CHECKBOOK MAINTENANCE PROGRAM

LEVEL II UPDATES***LEVEL II INDEX

CREDIT CARD INFORMATION STORAGE FILE

BEGINNER'S GUIDE TO MACHINE LANGUAGE AND ASSEMBLY

LANGUAGE

LINE RENUMBERING

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COMING SOON (GENERAL LEDGER, ACCOUNTS PAYABI E ANDRECEIVABLE, FORTRAN-80, FINANCIAL APPLICATIONS PACKAGEPROGRAMS FOR HOMEOWNERS, MERGE TWO PROGRAMSSTATISTICAL AND MATHEMATICAL PROGRAMS (BOTHELEMENTARY AND ADVANCED) , , , AND

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For writing letters, text, mailing lists, etc.. with eachnew subscriptions or renewal.

LEVEL II RAM TEST

(Cassette or Disk)

Checks random access memory to ensure lhai all memorylocations are working properly.

DATA MANAGEMENT SYSTEM

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Complete file management for your TRS-80'"

CLEANUP

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Fast action Maze Game.

:m ^-

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SEND FOR OUR NEW 48 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.

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BYTE May 1980 157

Text continued from page 50:address in the computer's memoryfrom which the data was written ontothe disk. All DTS numbers written onthe disk have the bits that indicate thedisk-drive number masked to 0 sothat the file can be read from any diskdrive, regardless of the drive in whichit was loaded when it was written.

The sector trailer is 4 bytes long.The first 2 bytes contain the checksum. The last 2 bytes, except in thelast sector in a file, contain the DTSnumber of the first sector of the file.In the last sector of the file, the last 2bytes of the sector trailer contain theaddress at which execution of thecontents of the file begins.

Software: The Basic Disk Routines

The basic disk routines handle headpositioning, drive selection, sectorselection, motor control, and com-putation of the check sum. Head posi-tioning is performed by the use of thestep and direction bits of the drive-select/status word (hexadecimal loca-tion CC03). Since the only indicationof the position of the head is thetrack-0 bit in the drive-select/status

KIMDOS is a KIM-1compatible version of thePercom MINIDOS diskoperating system.

word, the position of the head mustbe kept by software as a value inmemory.

In a multiple-drive disk system, it isdesirable to keep track of the headpositions of all drives in the system.The drive-selection routine (subrou-tine DRIV in listing 1) takes care ofthis. It saves the current track numberof the current drive, restores the cur-rent track of the desired drive, andlatches the desired drive into the con-troller. KIMDOS reinitializes thetrack registers (hexadecimal locations000F thru 0013) with each operationso that preservation of these bytes isnot necessary. However, if the systemshould be expanded with additionalsoftware, the track registers becomevery important. Inadvertant altera-

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tion of these locations would causereading or writing of the wrong track.

In a multiple-drive system, drivemotors are either all running or allstopped. The motors cannot be con-trolled individually since the drive-selection circuitry does not affect themotor-on signal. This necessitatessome special handling of drive selec-tion.

The drive-selection routine mustinsure that the write head is disabledbefore switching drives, or the areacurrently under the head of the newlyselected drive will be overwritten.The drive-selection routine must alsoinsure that the sector counter on thecontroller board is synchronized withthe newly selected drive. This can bedone only after at least one indexpulse has been received from the newdrive to reset the sector counter.

The sector-selection routine readsthe sector number from the con-troller. It must catch the leading edgeof the desired sector so that the reador write operation does not begin inthe middle of the sector; it does thisby looking for the change from theprevious sector to the desired sector.The sector-selection routine detectsthe disk-missing condition by settinga KIM hardware timer located on oneof the 6530 devices for a quarter of asecond. If the timer times out beforethe desired sector is found, theroutine assumes that the disk is notproperly inserted in the drive.

Read and Write Routines

The read and write routines are afundamental part of KIMDOS, whichis given in listing 1. Listing 2 is across-reference table for the symbolsused in listing 1.

The read routines are designed toautomatically try again to read incor-rectly read sectors. They will tryto read a sector up to six times beforereporting a read error. Intermittenterrors (such as those caused by ran-dom electrical noise, airborne con-taminants, slight fluctuations inmotor speed, small defects in thewritten data or track surface, or anycombination of the above) can berecovered by rereading the sector.

After a read error, the read routineacts as follows: first, the routinerereads twice. If that fails, the routinemoves the head to track 0 and back inan attempt to clear any interferingText continued on page 178

158 May 1980 © BYTE Publications Inc

The VIP hobby computer:Start programming for only $99

New! VP111Microcomputer..Assembled* and tested.

Features:

• RCA 1802 Microprocessor.

• 1K Bytes static RAM.Expandable on-board to 4K.Expandable to 32 K Bytes total.

• 512 Byte ROM operating system.

• CHIP-8 interpretive language ormachine language programmable.

• Hexidecimal keypad.

• Audio tone generator.Single 5-volt operation.Video output to monitor or modulator.Cassette interface—100 Bytes/sec.Instruction Manual with 5 video game

listings, schematics, CHIP-8, much more!

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All the features of the VP-111 plus:

• A total of 2K Bytes static RAM.

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• Built-in speaker.

• Plastic cover.

Three comprehensive manuals:

• VIP Instruction Manual—20 videogame listings, schematics, much more.

• VIP User's Guide—operating instruc-tions and CHIP-8 for the beginner.

• RCA 1802 User's Manual (MPM-201B) - complete 1802 referenceguide.

RC/1

COSMAC VIP lets you addcomputer power a boardat a time.

With easy-to-buy options, the versatileRCA COSMAC VIP means even moreexcitement. More challenges ingraphics, games and control functions.For everyone, from youngster to serioushobbyist.

Built around an RCA COSMAC micro-processor, the VIP is easy to programand operate. Powerful CHIP-8 inter-pretive language gets you intoprogramming the first evening.Complete documentation provided.

Send the coupon now...

Complete the coupon below and mail to:RCA VIP Customer Service, NewHolland Avenue, Lancaster, PA 17604.

Or call toll free (800) 233-0094

to place your Master Charge or VISAcredit card order. In Pennsylvania,call (717) 397-7661, extension 3179.

Please send me the RCA COSM AC VIP items indicated.Type Description Price

D VP-111 New low cost Microcomputer

(See description above) $99

D VP-114 Expansion Kit for VP-111—Includes

3K RAM, I/O Port and connectors... $ 76

□ VP-711 VIP—The original VIP Microcomputer

(See description above) $199

□ VP-44 RAM On-Board Expansion Kit—Four

2114 RAM IC's. Expands VP 711

memory to 4K bytes $ 36

D VP-S90 VIP Color Board—Converts VIP tocolor. Four background and eightforeground colors $ 69

□ VP-595 VIP Simple Sound Board—Provides

256 programmable frequencies. For

simple music or sound effects.

Includes speaker $ 30

D VP-550 VIP Super Sound Board—Turns yourVIP into a music synthesizer! Twoindependent sound channels. On-board tempo control. Outputs toaudiosystem $ 49

D VP-570 VIP Memory Expansion Board—

Plug-in 4K RAM memory. $ 95

D VP-580 VIP Auxiliary Keypad—Adds two-player interactive capability 16-keykeypad with cable. Connects tosockets on VP-590 or VP-585 $ 20

D VP-585 VIP Keypad Interface Board—Inter-faces two VP-580 AuxiliaryKeypadstoVIP $ 15

VP-560 VIP EPROM Board—Interfaces two

2716EPROMstoVIP $ 34

VP-565 VIP EPROM Programmer Board-Programs 2716 EPROMs.With software $ 99

VP-575 VIP Expansion Board—Provides 4buffered and one unbufferedexpansion sockets $ 59

VP-576 VIP Two-Board Expander—Allowsuse of 2 Accessory Boards in eitherl/Oor Expansion Socket $ 20

VP-601 ASCII Keyboard—128-characterASCII Encoded alphanumerickeyboard $ 69

Enclosed is $_

□ VP-611 ASCII/Numeric Keyboard—Same

as VP-601 plus 16 key numeric

keypad $ 89

D VP-620 Cable: Connects ASCII keyboards

to VIP $ 20

D VP-700 VIP Tiny BASIC ROM Board—BASIC

code stored in 4K of ROM $ 39

□ VP-710 VIP Game Manual—Listing for 16

exciting games $ 10

□ VP-720 VIP Game Manual-ll—More exciting

games (Available 2nd qtr.'80) $ 10

D MPM- CDP1802 User Manual—(Included

201B withVP-711) $ 5

□ Please send more information —

for items checked plus shipping & handling charge of $3.00.

Add your state and local taxes $ Total enclosed $

I enclose D check or □ money order or, charge my □ VISA/Bank Americard

□ Master Charge.

Credit card account No

Master Charge Interbank No

Signature (required for credit card orders):

Name (please type or print):

Street address:

State & Zip:

.Expiration date:.

City:

Telephone^ )

Make checks payable to RCA Corp. Prices and specifications are subject to changewithout notice.

Circle 96 on inquiry card.

BYTE May 1980 159

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160 May 1980 © BYTE Publications Inc

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CX40-04 Joystick Controller Pair $19.95

ATARI® 810 DISC DRIVE

List $699.95 OUR PRICE $589

Circle 97 on inquiry card.

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T.I. 810 Printer

Bi-directional; 150 cps; logic seeking; adjust-able tractor. Available with lower case com-pressed print; Forms Length Control orVertical Forms Control option.TI-810 Basic Unit, List $1895 ONLY $1695TI-810 w/full ASCII (lower case), vertical

forms control, and compressed print . $1895TI-825 75 cps, w/lower case, List $1565

$1395

NECSpinwriter

TM

5510 or 5530 Centronics parallel interface

w/Tractor, List $3285 ONLY $2889

5510 or 5530 w/o Tractor, List $3265 . . . $2689

Call us for Centronics, Integral Data, PaperTiger, Anadex, Okidata, et.al.

Televideo TVI-912

OUR PRICE ONLY $789

Upper case and lower case; 15 baud rates: 75to 19,000 baud; dual intensity; 24 x 80-char.display, 12 x 10 resolution. Numeric pad.Programmable reversible video; aux. port;self-test mode; protect mode; block mode;tabbing; addressable cursor. Microprocessorcontrolled; programmable underline; line andcharacter insert/delete.

$10,000 Value!

Complete Business System

on'y $5995

(Price includes air freight shipping)

VECTOR SYSTEM B, complete with Vector Mind-less Terminal, 64K of RAM, Dual Floppy Disks (630 kilobytes of storage),and printer ... so complete, you'll get all cables, box of 10 Floppy Disks, and EVEN a boxof 3500 sheets of Fanfold Paper.

OVER $3500 OF SOFTWARE INCLUDED!!!

Digital Research's 2.0 CP/M™ Disk Operating System,Interpreter, Microsoft 80 BASIC

PEAOHTfiEESOFTWARE

AND one of the finest Business Packages —from Retail Science's PEACHTREE SOFTWARE:

• GENERAL LEDGER

• ACCOUNTS RECEIVABLE

• ACCOUNTS PAYABLE

• INVENTORY

• PAYROLL

The System B doubles as an EXCELLENT

Word Processing System (Software at slight additional cost).

System may be expanded for multi-user time-sharing

data and word processing! Up to 5 terminals

at nominal cost.

Unless otherwise specified, shipping charges are additional. All prices subject tochange and all offers subject to withdrawal without notice. Prices in this ad are forprepaid orders. Slightly higher prices prevail for other-than-prepaid orders, i.e.,C.O.D., credit card, etc.

— WRITE FOR FREE CATALOG —

MiniMicroMart

1618 James Street, Syracuse NY 13203 (315) 422-4467 TWX 710-541-0431

MiniMicroMart:

Your No. 1 Supplier

of Systems for Business

Applications and WordProcessing...

HARD DISKS

MiniMicroMart is your best source

for Hard Disk Systems!

Cromemco, North Star, Vector,

Dynabyte, Morrow Thinker Toys®

Corvis, Lobo, et. al.

LJ U U L_:

■!

North Star Horizon 2 Cromemco System 3

32K 4 MHz, dual-drive, with double density controllerboard, two RS232C serial ports, a parallel port. Included isDOS and North Star Extended Disk BASIC.

Horizon 2, 32K, DD, List $3095 ONLY $2619

32K, Quad Density, List $3595 $3049

64K, Double Density ($3830) $3239

64K Quad System also available.

Features 4 MHz CPU, 64K of RAM, dual-sided Per-Sci 299BFloppy Disk Drive, RS232C interface, and printer interface.

Cromemco System 3, List $6990 ONLY $5890

System 2, List $3990 OUR PRICE $3390

Z-2H Hard Disk Computer System, List $9995 $8489

Complete your system with aTerminal, Printer, Business Software:

TM

SUPRBRAIN

32K or 64K totally self-containedcomputer, uses two Z-80 CPU's.Commercial-type terminal with 12"monitor (like the Intertube). Dualdouble density minifloppies (quaddensity available). Comes withCP/M™operating system; BASICincluded.

32K, List $2995 ONLY $2685

SuperBrain, 64K OUR PRICE $2883

Circle 98 on inquiry card.

INCLUDES:

• Your choice of Terminal

P-E Bantam 500Intertube IITelevideo912SOROC 120

• 10 Floppy Disks

• Two RS232 Cables

• Software with Manuals

General LedgerAccounts ReceivableAccounts PayablePayroll

• 3500 Sheets of Paper

• Anadex DP-8000 Printer

Over $2500 Value .. .Limited Time Special $1795

With T.I. 810 Printer - Retail Value over $3400 .. ONLY $2595

When purchased with SuperBrain (Terminal not required or furnished)

With Anadex DP-8000 Printer $1049

With T.I. 810 Printer $1695

- THIS OFFER EXPIRES JULY 10, 1980 -

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Record keeping problems? Our CCA DataManagement System solves them easily.

Having information at your fingertips can make your job awhole lot easier. And that's what the CCA Data ManagementSystem is all about.

With this Personal Software'" package and an Apple II'"or TRS-80'" disk system, it will be far easier to keep inven-tories, customer lists, accounts receivable and payable records,patient histories and many more items.

In fact, you can use the CCA DMS for all of your datamanagement needs, rather than buying (expensive) or writing(time consuming) separate programs for each applica-tion. That's because DMS lets you create your ownfiling systems, adapting itself to the types of recordsyou keep. You specify the number and names ofeach data field—without any programming.

With DMS keeping all of your records, you onlyhave to learn how to use one system. That'seasier, too. It's menu driven, with plenty of Iprompts to help you create files and add,update, scan, inspect, delete, sort, con-dense and print data. Our compre-hensive 130-page step-by-stepinstruction manual even providescomplete "how to" inventory andmailing list applications so youcan start processing immediately.

DMS is a very powerful sys-tem, with more file and recordstorage capacity than other database programs on the market.

'Apple is a trademark of Apple Computer,Inc.; TRS-80 is a trademark of the Radio ShackDiv. ofTandy Corp.

Circle 99 on inquiry card.

And it also gives you greater data handling flexibility. To cus-tomize DMS, write add-on BASIC programs that read or writeDMS files and perform any kind of processing you want.

You can sort and print your data in nearly any form ofreport and mailing label you want. Sort data by up to 10 fieldsfor zip code, balance due, geographic location or whatever.And print reports with subtotals and totals automaticallycalculated.

The CCA Data Management System, written by CreativeComputer Applications, has two years of field testing on othermicrocomputers. Now Personal Software makes DMS avail-able on the TRS-80 Level II and Apple II and II Plus 48kdisk systems. And at under $100, DMS is also easy to afford.One demonstration will convince you how easy com-puterized record keeping is. Ask your Personal Softwaredealer to show you. To locate your nearest dealer,contact Personal Software, Inc., (408) 745-7841, 592Weddell Dr., Sunnyvale, CA 94086.

See us at NCC booth 48 and 49.

€0$

BYTE May 1980 167

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168 May 1980 © BYTE Publications Inc

Settle lor Morefrom Tfotir TRS-80

BASIC Compiler, with trs-so basic

Compiler, your Level II BASIC programs will run atrecord speeds! Compiled programs execute anaverage of 3-10 times faster than programs rununder Level II. Make extensive use of integeroperations, and get speeds 20-30 times fasterthan the interpreter.

Best of all, BASIC Compiler does it with BASIC,the language you already know. By compilingthe same source code that your current BASICinterprets, BASIC Compiler adds speed with aminimum of effort.

And you get more BASIC features to programwith, since features of Microsoft's Version 5.0BASIC Interpreter are included in the package.Features like the WHILE . . WEND statement, longvariable names, variable length records, and theCALL statement make programming easier. Anexclusive BASIC Compiler feature lets you callFORTRAN and machine language subroutinesmuch more easily than in Level II.

Simply type in and debug your program asusual, using the BASIC interpreter. Then enter acommand line telling the computer what tocompile and what options to use.

Voila! Highly optimized, Z-80 machine codethat your computer executes in a flash! Run it nowor save it for later. Your compiled program can besaved on disk for direct execution every time.

Want to market your programs? Compiled ver-sions are ideal for distribution* You distribute onlythe object code, not the source, so your geniusstays fully protected. ,^ ___

BASIC Compiler runs on yourTRS-80 Model I with 48K and diskdrive. The package includesBASIC Compiler, linking loaderand BASIC library with completedocumentation. $195.00.

MORE

FROM

MICROSOFT

'Microsoft royalty information forthe sale of programs compiledwith BASIC Compiler is availablefrom Microsoft.

muMflTH Symbolic Math System

expands your TRS-80 beyond the limits of numeri-cal evaluation to a much higher level of mathsophistication.

Symbolic mathematics is muMATH's power. Forthe first time, algebra, trigonometry, calculus,integration, differentiation and more can be per-formed on a system smaller than an IBM 370. Andin a fraction of the time you could do themmanually.

Yet for all its power, muMATH is simple to use.To perform a differentiation you could enter:?DIF(A'XT3 + SIN(XT 2),X);

In almost no time, the computer would replywith: @2*X*COS(XT 2] + 3*A*X T 2.

Or to add fractions: ?1/3 + 5/6 + 2/5 + 3/7;The instantaneous answer: 419/210.Or to perform a more difficult trigonometricexpansion you enter: SIN(2*Y]*(4*COS(X)t3-COS(3*X) + SIN [Y)*(COS(X+Y+#PI) -COS[X-Y));

Just a few seconds later, the computer replies:@4*SIN(Y)*COS(X)*COS[Y).

muMATH has virtually infinite precision with fullaccuracy up to 611 digits.

If you use math, you'll find countless ways to savetime and effort with muMATH. It's a professionaltool for engineers and scientists. A learning toolfor students at any level from algebra to calculus.And if you want to expand your capabilitieseven beyond the standard muMATH, the option isopen. muSIMP, the programming language inwhich muMATH is written, is included in the muMATH ,r^s package. A superset of the lan-guage LISP, muSIMP is designedespecially for interactive symbolicmathematics and other artificialintelligence applications.

muMATH and muSIMP were

written by The Soft Warehouse,

Honolulu, Hawaii. Priced at $74.95,

the package includes muMATH,

muSIMP and a complete manual.

It requires a Model I TRS-80 with

32K and single disk. muMATH

for the Apple II Computer will

be available later this year.

J

You can buy muMATH and BASIC Compiler at computer stores across the country that carry Microsoftproducts. If your local store doesn't have them, call us. 206-454-1315. Or write Microsoft ConsumerProducts, 10800 Northeast Eighth, Suite 507, Bellevue, WA 98004.

/HICAOSOfT

V CONSUMER^ PRODUCTS^

Circle 100 on inquiry card.

BYTE May 1980 169

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170 May 1980 © BYTE Publications Ire

NEECO

proudly COMMODORE'S NEW 8000

INTRODUCES SERIES (80 column) COMPUTERS

$1695 (available May/June '80)

CBM™ 8050 DUAL DRIVE FLOPPY DISK

The CBM 8050 Dual Drive Floppy Disk in an enhanced ver-sion of the intelligent CBM 2040 Disk Drive. The CBM 8050has all of the features of the CBM 2040, and provides morepowerful software capabilities, as well as nearly one meg-abyte of online storage capacity. The CBM 8050 suppliesrelative record files and automatic diskette initialization. Itcan copy all the files from one diskette to another withoutcopying unused space. The CBM 8050 also offers improvederror recovery and the ability to append to sequential files.HARDWARE SPECIFICATIONS FIRMWARE

Dual Drives

Two microprocessors

974K Bytes storage on two 5.25"

diskettes (ss)Tracks 70Sectors 17-21Soft sector formatIEEE-488 interfaceCombination power (green) and

error (red) indicator lightsDrive Activity indicator lightsDisk Operating System Firmware

(12KROM)Disk Buffer (4K RAM)

DOS version 2.0Sequential file manipulationSequential user filesRelative record filesAppend to sequential filesImproved error recoveryAutomatic diskette initializationAutomatic directory searchCommand parser for syntaxvalidationProgram load and save

CBM1

8000 SERIES BUSINESS COMPUTERS

The new Commodore 8000 series computers offer a wide screendisplay to show you up to 80-character lines of information. Textediting and report formatting are faster and easier with the newwide-screen display. The 8000 series also provides a resident Oper-ating System with expanded functional capabilities. You can useBASIC on the 8000 computers in both interactive and programmodes, with expanded commands and functions for arithmetic, edit-ing, and disk file management. The CBM 8000 series computers areideally suited for the computing needs of the business marketplace.

SCREEN

2000 character display, organized

into twenty-five

80-column lines64 ASCII, 64 graphic characters3x8 dot matrix charactersGreen phosphor screenBrightness controlLine spacing: 1 'A in Text Mode

1 in Graphics ModeKEYBOARD73-key typewriter style keyboard

with graphic capabilitiesRepeat key functional with

all keysMEMORYCBM 8016: 16K (15359 net)

random access memory (RAM)CBM 8032: 32K (31743 net)

random access memory (RAM)POWER REQUIREMENTSVolts: 110VCycles: 60 HzWatts: 100

SCREEN EDITING

CAPABILITIES

Full cursor control (up, down,

right, left)Character insert and deleteReverse character fieldsOverstrikingReturn key sends entire line to

CPU regardless of cursor

position

INPUT/OUTPUTParallel portIEEE-488 bus2 cassette portsMemory and I/O expansion

connectorsFIRMWARE24K or ROM contains:

BASIC (version 4.0) with direct

(interactive) and indirect

(program) modes9-digit floating binary arithmeticTape and disk file handling

software

The 8000 Series will be available May/June '80Model 8016 Model 8032 2040 Dual Floppy

$1495 $1795

$1295

Available June/July

$395

CBM™ IEEE MODEM

SPECIFICATIONS

'Full or half duplex operation*300 bits per second'Standard IEEE 488 interface'Switch selectable originate, off,

answer-full duplex, test, half duplex•Visible indicators are transmit data,

receive data, carrier ready, test'Frequency shifted modulation"Bell 103/113 compatible

"Execeptional performance ■even on noisy phone lines"

*CBM is a registered trademark of Commodore. All prices and specifications are subject to change without notice.

NEECO

679 Highland Ave.Needham, MA02194

Mon-Fri 9:30-5:30

MasterCharge &

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Telex: 951021

MICROAMERICA DISTRIBUTING

"Nationwide distributors of Computer Equipment"21 Putnam StreetNeedham, MA

02194 (617)449-4310

Circle 101 for microamerica

Circle 102 for NEECO

BYTE May 1980 171

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May 1980 © BYTE Publications Inc 173

Canned Programs are Only a Beginning. Pre-programmed disks and cassettes are a terrific wayto get started in micros. But they're just a start.The best thing about owning a computer is pro-gramming it. Yourself.

University Software makesit easy. Using compact,easy-to-understandMicrosoft BASIC,University Software hasselected the best workof scores of differentauthors to create thisspiral-bound, five-volumeset of the programs youmost want to have. Allyou have to do is sitdown at the keyboardand enter them.

Software for People.The

problem with BASIC as alanguage is that it was de-veloped on timeshare andother large capacitycomputers. But Microsoft BASIC was specificallydesigned to run on micros; it's fast, it's simple,and memory requirements are minimal.

All the programs in the University Software setwere written on micros, for micros. If you own aTRS-80, Apple, Texas Instruments, Atari, Com-modore PET, Sorcerer, or Ohio Scientific micro,

DOIT

University Software gives you

these programs were designed to work right —the first time — on your machine.

What's more, they're programs you can use.The Small Business text contains programs tohelp you look at interest rates every possible way,a materials inventory program, a touch typingcourse and a small business accounting system.But that's only the beginning. Among the Educa-tion and Scientific programs, you'll find a speedreading course, a President's quiz, a math educa-tion program, and programs to help you learnEnglish and build your vocabulary. The two vol-

A University Software Sampler

Here is a small sample of the programs you'll get in eachof the five University Software volumes.

HOME & ECONOMICS-$24.95Text Editor: Compose and correctyour notes, letters, invoices.Utilities: Electric, water, phone, gasand trash bills control.Temperature Conversion: Lets youconvert different temperature units.Eternal Calendar: Returns the day ofthe week for a given date.Recipes Book: Sets up recipes on cas-sette tape.

Checking Account: Checkbook analysis.... Plus 9 more!

FUN & GAMES Volume 1 -$14.95Space Race: You command FederationTrading Ships in the Asteroid Belt.Mastermind: Players attempt to figureout one another's combinations.Combat: Battle game employingnumbered board on screen.Biorlujthm: Physical, emotional andintellectual patterns.Merchant of Venus: Make money inouter space.... Plus 10 more!

FUN & GAMES Volume II-$14.95Blackjack: The famous card game.World War 111: War game.Bridge: Deals four hands on screen.

Battlestar Gnlactica: You have to reachEarth passing many Cvlon stations.. ..Plus 17 more!

EDIICA TION & SCIENT1FIC-S34.95Astronomical Computations: Computethe positions of the planets; draworbits.

Pythagorean Theorem: Review geom-etry theorems.Word Search: Spelling puzzle.Quantum Chemistry: Compute quan-tum numbers of an atom.Program Manager: Load and run mul-tiple programs....Plus 21 more!

SMALL BUSINESS-$49.95Mortgage Analysis: Outputs loantables.

Distributions Mapping: Maintains li-brary of distribution functions.Billing System: Creates and managesdata Dase containing bills.Investment Management: Analysis ofstocks, funds, debentures, real estate.Small Business Accounting: Posts in-come and expenses, prints trial bal-ance; chart of accounts.Tax: Federal Income and F.I.C.A.taxes.... Plus 22 more!

Act now for your FREE BOOK

You can order each of thesevolumes separately NOWthrough Folio Books. But if youcall today and order the entireset, we'll include MicrosoftBASIC, a standard introductoryguide to the use of the languageby Ken Knecht absolutely FREE.

Offer expires June 30, I9S0

174 BYTE May 1980

YOURSELF.

105 Microsoft programs. For less than a buck and a half apiece.

umes of Fun & Games programs offer a total of 35games and graphics to challenge every level ofskill. Finally, the Home & Economics text con-tains the programs you need to help you manageyour life more efficiently — an appointmentscalendar, metric conversions, and programs tohelp you balance your checking account andbudget the family income.

Do Your Pocketbook a Favor. It's this simple: ifyou input your own programs, you save money.Lots of money. Preprogrammed cassettes anddisks nowadays cost anywhere from $10 to up-wards of $50. And if the program you want is notavailable in a format for your computer, you'rejust flat out of luck.

If you buy the entire set of University Softwareprograms, on the other hand, you get 105 pro-grams for $139.75—about $1.33 each. Plus, there'sa conversion appendix in the back of each volumeto help you convert any Microsoft BASIC pro-gram written on one computer to run on yours.

Do Yourself a Favor. To really master and under-stand your computer, you can't be content to sitback and let it do all the work. You've got to roll upyour sleeves and accept the challenge to your owncreativity. University Software programs will helpyou run your life. And they'll help you grow.

You can order any of the University Softwarevolumes separately, but if you act now and orderthe entire set, we'll include Ken Knecht's Mic-rosoft BASIC, a complete introduction and tutorialbook on programming in Microsoft BASIC,FREE! It's yours—a $10 value—just for orderingthe whole University Software set at one time.

Circle 103 on inquiry card.

We'll jump right on your order. There's only oneplace you can get the entire University Software setshipped directly to you almost as soon as you call:Folio Books. We are specialists in computer booksfor micro and mini computers, and honestly be-lieve that University Software is the finest set ofapplication Microsoft programs available to thegeneral public.

Call us today. Do it for yourself.

ORDERING INFORMATION: Call toll-free(800) 423-4864, M-F 9-5 p.m. Pacific Time. Mailorder: include name, address and telephone. M/Cand Visa customers include: your name as it ap-pears on your card, card number, expiration date.All orders add $1.00 per volume for shipping andhandling. California residents add 6% sales tax.We ship UPS or Parcel Post. Introductory offer:order 3 or more volumes and receive a 10% dis-count; order all 5 and we also pay shipping any-where in U.S.A.

(800)423-4864

In California call collect: (Z_L3) 7yD~D2.2A.

University Software is available from

Folio Books

P.O. Box 4100-H, Los Angeles, California 90041

University Software Also Available at Leading Computer Stores Everywhere.

BYTE May 1980 175

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►-J ^ s ^ z :: r a c d o i i d. a i a i i ; i i i : i i i cc i i id U3 'j] 'Ji 'Ji rJ3 'J 'VJ3 'j] iv.v.t '.i:i :n v: 3 U3 -^ vi -0 uT a 3 -^ ^j 1— i—176 May 19S0 © BYTE Publications Inc

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BYTE May I960 177

Text continued from page 158:particles from the head surface. Inaddition, this operation insures thatthe head is on the proper track.Another three reads are attempted; ifthis fails, the data is assumed to beunrecoverable.

The memory locations that must beinitialized before a read operation aregiven in table 4.

The write routines write a con-tiguous block of memory to the diskon the required number of sequentialsectors. They are also responsible forcalculating the forward andbackward links and the check sum foreach sector. Each sector except thelast contains 256 bytes of data; if thenumber of bytes to be saved is not aninteger multiple of 256, the last sectormay be shorter. Each sector is preced-ed by 16 bytes of Os before the synccharacter. This is followed by the sec-tor header, the data, and the trailer.No read operation is done afterwriting to verify the data, because theinfrequency of write errors does notwarrant the extra overhead.

The memory locations that must beinitialized before an area of memorycan be saved on disk are given intable 5.

Control Routines

The routines SAVK and LODKprovide the interface between the userand the disk routines. These routinesexpect the appropriate information to

be preset in memory by use of theKIM keyboard. The only incompati-bility with the Percom MINIDOSroutines here is in the indication of anomitted value. The Percom routinesuse the value hexadecimal FFFF toindicate a field not in use, andKIMDOS uses a high-order byte of 0.This is not important since the 6800and 6502 microprocessors store theirhigh- and low-order address bytes inthe opposite order and are not com-patible anyway.

The control routines SAVK andLODK convert their parameters intothe proper format where necessaryand call the disk subroutines. Uponreturn, these two routines display theresults of the requested operation onthe KIM display and return control tothe KIM monitor. The informationdisplayed is either the DTS number ofthe last sector read or written indecimal, or FFrm, where nn is anerror code. The error codes are givenin table 6.

Interrupts

In any system, it is often desirableto use interrupts for various pro-cesses. Because KIMDOS is involvedin time-critical functions when doingdisk input/output (I/O), an interruptat the wrong time could cause cata-strophic errors. Therefore, the non-maskable interrupt (NMI) line cannotbe used during disk I/O.

However, KIMDOS does allow for

the use of the maskable interrupt re-quest (IRQ) line. This is done by sav-ing the status register and disablingthe IRQ line before starting any time-critical functions. The status registeris then restored after the critical func-tion is completed. This causes the ser-vicing of the IRQ interrupt to bedelayed for as much as 20 ms at atime. Any interrupt-driven systemthat can tolerate this limitation canfunction properly with KIMDOS.

Testing

Since the drive and controller bothcome assembled and tested, thecheckout procedure is relatively sim-ple. The only equipment I used was alogic probe and a multimeter.

The first step is to connect the driveand controller to the KIM bus andverify all power-supply voltages.When they are correct, basic com-munication with the controller can beverified by entering the hexadecimaladdress CC05 via the KIM-1 keypad.This should start the motor and keepit on until the address is changed. Ifthe motor does not start, then there isprobably a bad connection to KIM.

Next, the motor-off pulse can bechecked by pressing the + key on theKIM keypad to increment the addresson the display to hexadecimal CC06.This should turn off the motor imme-diately. The motor time-out circuitcan be checked by entering hexa-decimal CC05 on the KIM display,

HexadecimalAddress

0016, 0017

Contents

001C, 001D

Beginning memoryaddress (optional;substitute 0 to useaddress stored in thedisk file)

Drive/Track/Sector(DTS) number of firstsector in the file beingread

Table 4: Information required to read afile into memory from disk. The filebeing read into memory will begin atthe address pointed to by hexadecimalmemory locations 0016 and 0017.However, if the contents of thesetwo bytes are 0, the file will be loadedinto memory beginning at the addressstored with the file. The DTS numberis stored here in binary-coded decimalformat, with the high-order bytestored first.

HexadecimalAddress

0008, 0009

000A0019, 001A

001C, 001D

001E, 001F

Contents

Beginning address ofmemory to be savedFile type

Execution address(optional ; use 0 to omit)Drive/Track/Sectornumber of first sector tobe writtenEnding address ofmemory to be saved

Table 5: Information required to save afile. These are the hexadecimalmemory locations that must be setbefore the SAVK (save a file) routinefrom listing 1 is called. The DTSnumber is stored here in binary-codeddecimal format, with the high-orderbyte stored first.

Error Code

Message

0

Disk missing (given after

read or write operation)

1

Disk protected (given

after write operation

only)

2

Invalid sector number

(given after read or

write operation)

3

Blank sector (given after

read operation only)

4

Disk overrun; attempted

to write more than 349

sectors

5

Permanent read error

Table 6:

List of disk-related error

codes. If a read or write operation ends

in failure,

the left four digits of the

KIM display will read FFnn, where nn

is one of the error codes listed in this

table.

178 May 1980 © BYTE Publications Inc

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BYTE May 1980 179

Hard sectoring means thatsector boundaries aredetected by means ofholes punched in the flop-py disk.

followed by another address. Themotor should run about 3 secondsand stop.

Now the sector-counting circuitrycan be checked. With a disk insertedin the drive, enter hexadecimal CC05and then hexadecimal CC02. Therightmost digit of the KIM display(which shows the low nybble of thecontents of hexadecimal locationCC02) should be rapidly changing aslong as the motor is running. Whenthe motor stops, this digit should con-tain a decimal digit (0 thru 9) indi-cating the last sector passed.

After all of the previously mention-ed tests have been completed, thesoftware can be used to do furthertesting. The TEST routine, given inlisting 3, is included for this purpose.TEST does a static test of most of thecontroller functions and their interac-tion with various subroutines withinKIMDOS. It uses the number of thekey pressed on the keypad as an indexinto a table of subroutine addresses.From there, it does a subroutine jumpto the routine thus addressed.

Upon return, the TEST routine dis-plays the value of the accumulator inthe rightmost two digits of the KIMdisplay. It also displays the value ofthe carry flag in the left four digits —FFFF for carry set and 0000 for carryclear. (This is done for those routinesthat return the carry flag set as anerror indicator and use the value inthe accumulator as an error code.)

Execution of the TEST routinebegins at hexadecimal 0200. Theappropriate data must be set in the 0page for the subroutines to be tested.Some subroutines must be usedtogether. For example, the motormust be started and the drive must beselected before the head-movementroutines will work. To add moresubroutines, increase the value in thecompare instruction at hexadecimallocation 020C and add the appro-priate addresses to the end of thetable.

The final test that I had to do was

Listing 3: Listing for program TEST. This program executes a given KIMDOS routine(see documentation at the beginning of the listing) depending on which key on the KIMkeypad is pressed.

Hexadecimal Object Label Instruction OperandAddress Code Mnemonic

Commentary

0001 :

0002:

rEST : ROUTINE

TO TEST

THE BASIC DISK

0003:

DRIVER SUBROUTINES

0004:

0005:

SUBROUTINES UNDER TEST

0 0 06 :

0007:

sun

ADDREb

S KEY/y

0008:

2000

CTKX

#

$0022

0

CO TO TRACK 0

0009:

2000

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#

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1

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1/0

0010:

2000

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2

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0011:

2000

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#

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3

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0012:

2000

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4

MOVE HEAD IN 1

00 13 :

2000

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*

SC060

5

FIND TRACK IN 0 1

0014:

2000

OTSC

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$0147

6

FIND SECT0H IN 02

0015:

7

RETURN TO KIM

0016:

0017:

1

<IU ADDRESSES

00 18:

00 19:

2000

SCND

#

$1F IF

0020:

2000

F.ETK

♦

$1F6A

002 1 :

2000

KIM

*

$1C4F

0022:

0023:

ZERO PAGE STORAGE

0024:

0025:

2000

T0A0

*

$0020

0 0 26:

2000

TrnQ

*

$0021

0027:

2000

SAKE

*

$0022

0028:

2000

PNTH

*

$00FB

0029:

2000

PNTL

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$00FA

0030 :

2000

INH

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0031 :

0032:

2000

ORG

$2000

0033:

0034:

2000

20

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1F

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0 035:

2003

20

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0036:

2006

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2008

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2000

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2010

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0 042:

2011

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0 074 :

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0020

TOD0 0021

180 May 1980 © BYTE Publications Inc

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to read and write data using a floppydisk previously recorded in thePercom format. I did this to confirmthat the KIMDOS software producesresults using the controller board anddisk that are identical to the resultsproduced by the Percom 6800 code.Since I found this to be the case, noone using KIMDOS needs to repeatthat test.

Error Recovery

As in all systems, there will occa-sionally be unrecoverable errors. ThePercom format allows for recovery ofbroken files. Since each sector con-tains the DTS number of the first sec-tor of the file, each sector can beassociated with its file. Reading doesnot have to start with the first sector;it can start on any sector and willcontinue to the end of the file.

When a read error occurs, tryrereading the sector several times.Also try to read a sector on anothertrack of the disk (to move the headaround some) before rereading theoriginal sector in error. Reinsertingthe disk may also help. If all of theabove measures fail, then execute theroutine LAST at hexadecimal address

Alternating-sectoraddressing allows time forthe housekeeping routinesthat must be executed be-tween reading and writingsectors.

C378. This will display the number ofthe sector containing the error. To trya partial recovery, start the readoperation at one sector past thedisplayed address. If that fails, try thenext sector, and so on. Any valid sec-tor can be read in this way. A filemay have only one bad sector, withthe rest readable.

Expansion

To fully utilize the features of theLFD-400 disk system, a more exten-sive disk-operating system is neces-sary. This software is designed to bethe basis of such a system. Thesesubroutines can be used to performthe basic functions needed by a largerdisk-operating system that provides

for named files, automatic spacemanagement, and buffered I/O.

To facilitate expansion, KIMDOShas a jump table located at the begin-ning of the executable code that con-tains JMP instructions to all subrou-tines in KIMDOS needed by externalsoftware. This allows KIMDOS to beupdated (in case of bugs or enhance-ments) without reassembling the call-ing routines. With the nine routines inthe jump table, any disk I/O can beperformed under external programcontrol.

RSEX and WSEX are used to readand write individual sectors. To usethem, the data at hexadecimal loca-tions 0000 thru 000A must be sup-plied. (See the beginning of listing 1.)To read an individual sector, thealternate address pointer, hexa-decimal locations 0016 and 0017,must point to the starting location ofthe file when it is loaded intomemory. If the value of the alternateaddress pointer is 0, the sector willload beginning at an address stored inthe sector header. Similarly, to writean individual sector, the data pointer,hexadecimal locations 0014 and 0015,must point to the beginning byte of

Ng^ Produced and widely used in England and U.S.A.COMPLETE BUSINESS PACKAGE

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PROGRAMS ARE INTEGRATED-

01 = ENTER NAMES/ADDRESS, ETC02= ENTER/PRINT INVOICES

03 = ENTER PURCHASES

04 = ENTER A/C RECEIVABLES

05 = ENTER A/C PAYABLES

06= ENTER/UPDATE INVENTORY

07 = ENTER/UPDATE ORDERS

08 = ENTER/UPDATE BANKS

09 = EXAMINE/MONITOR SALES LEDGER

10 = EXAMINE/MONITOR PURCHASE LEDGER

11 = EXAMINE/MONITOR (INCOMPLETE RECORDS)

12 = EXAMINE PRODUCT SALES

SELECT FUNCTION BY NUMBER-

13 = PRINT CUSTOMER STATEMENTS

14 = PRINT SUPPLIER STATEMENTS

15 = PRINT AGENT STATEMENTS

16 = PRINT TAX STATEMENTS

17 = PRINT WEEK/MONTH SALES

18= PRINT WEEK/MONTH PURCHASES

19 = PRINT YEAR AUDIT

20= PRINT PROFIT/LOSS ACCOUNT

21 = UPDATE END MONTH FILES MAINTENANCE

22 = PRINT CASH FLOW FORECAST23= ENTER/UPDATE PAYROLL (NOT YET AVAILABLE)24 = RETURN TO BASIC

WHICH ONE? (ENTER 1-24)

01 SUB. MENU EXAMPLE: 01 = EXAMINE: 02 = INSERT: 03 = AMEND: 04 = DELETE

05 = PRINT (1,2,3): 06 = NUMERIC COMBINATIONS: 07 = SORT

VERY FLEXIBLE. ADD YOUR OWN FUNCTIONS. EASY TO INTEGRATE.

All programs In BASIC for CP/M. PET. 6800

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£575 Stock Integrated Option + £100 Bank Integrated Option + £100

182 May 1980 © BYTE Publications Inc

Circle 107 on inquiry card.

■

\bu KnewTarbell

But, do you know oil the com

Tarbell has ready for you?

When someone soys "Tarbell" there'sno doubr what's meant.. . the cas-sette interface whose reliability andsolid engineering made it an in-dustry standard.

Since that first breakthrough-product, Don Tarbell has expandedhis list of useful, dependable com-ponents . . . components to meetyour needs of today, and keep youprepared for tomorrow.

Check this partial list of quality com-ponents Don Tarbell has ready foryou. You're probably ready forthem, right now.

• When it comes to RAM memory,Tarbell means reliability. 16K and32K static memory that offers youeasier trouble shooting, and fareasier maintenance. Rememberthat.

• Tarbell BASIC brings simplicity andsophistication to your programs. OurBASIC is easier to program, and offersunique commands and statementsnot found in regular BASICS underany name.

• CP/M® disk operating system is,of course, the standard for softwareexchange. At Tarbell we provide ourown approved CP/M system mod-ified for all Tarbell floppy disk inter-faces. Note. We also have MP/M® forthose interested in multi user systems.

• The Tarbell VD5 line comes as acomplete package ... or, as sep-arate units. For example, the Tarbellmainframe can be ordered with 1or 2 Shugarf or Siemens drives, orno drives. Whichever way you go,you get the reliability of Tarbellrested components.

• With the Tarbell Double Densityfloppy disk interface, storage capa-city, speed and versatility are greatlyIncreased. Under our DD CP/M, singleand double density disks may beintermixed with no penalty. Thesystem automatically determineswhich Is in place.

We also still have our Single Densityfloppy disk interface. It's specificallydesigned to operate with many dif-ferent and unusual drives. Naturally,they're Tarbell rested.

950 Dovlen Place, Suite BCarson, California 90746(213) 538-4251 / 538-2254

*CP/M & MP/M are products of Digital Research Corp.

Circle 108 on inquiry card.

BYTE May 1980 183

Since the drive and con-troller both come assem-bled and tested, thecheckout procedure isrelatively simple.

the area to be stored on the disk file.All head positioning and drive pre-paration is taken care of.

LODX and SAVX are the subrou-tine versions of LODK and SAVK.They require the same data as LODKand SAVK, except that the DTSnumber must be converted to threesingle-byte quantities and storedin hexadecimal locations 0000 thru0002. The subroutine PREP can beused to select the desired drive andseek the desired track. The CVTBINand CVTDEC subroutines convertthe DTS number to binary anddecimal, respectively. SubroutineFWDC calculates the next sector in afile. The INITDV subroutine sets thetrack registers to hexadecimal FF. Ifany errors are encountered, control is

returned to the calling routine withthe carry bit set and the error code inthe accumulator. This allows com-plete external control of the disksystem.

Since developing KIMDOS, I havedeveloped ZAPDOS. ZAPDOS ismodeled after Percom's MINIDOS-PLUSX disk-operating system. Itallows loading and saving of up tothirty-one named files per disk. Itoccupies the upper two read-only-memory sockets in the LFD-400board. ZAPDOS contains thirteenread-only-memory resident com-mands to manipulate and display diskspace and memory. When used withits ten disk-resident utility programs,ZAPDOS transforms KIM into apowerful microcomputer system.

Conclusion

I have been independent of cassettetape for over two years now. It hasbeen a great pleasure to be able toload even the largest file in 1 or 2seconds. I no longer leave my KIMsystem on for days to keep fromspending the time necessary to writeall of memory to tape and verify thatthe tape is good. The Percom

LFD-400 is a viable and cost-effectiveanswer to the mass-storage problem.KIMDOS should be easily con-verted for use on other 6502 systems.An interface for the Apple II shouldbe straightforward. KIMDOS isavailable in a 2708 read-only memoryfrom Percom. (See below.) I wouldlike to express thanks to Bob Haas forhis valuable consultation on thisproject. ■

Percom Data Company (211North Kirby, Garland TX 75042) ismaking available the current ver-sion of KIMDOS on a 2708 eras-able programmable read-onlymemory (EPROM) part to be usedon the disk-controller board of thePercom LFD-400 5-inch floppy-disk drive. This can be obtainedalong with a Percom LFD-400 diskdrive for $15 above the currentprice of the disk-drive unit. A flop-py disk containing KIMDOS-re-lated software (including the ZAP-DOS disk-operating system men-tioned at the end of this article) isalso available from Percom.

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184 May 1980 © BYTE Publications Inc

Circle 109 on inquiry card.

EITEEI'TEEITE

d

TDQLS

nJCBQCQIVIPJTIMG:

flBVTECONFERENCE

EfTEEUEEUE

June 16-17,1980McGraw-Hill World Headquarters

New York City

The microcomputer revolution in system design,engineering, and technology is here!

Sophisticated 32 bit computer architectures areappearing in single packages that may be used in a personalcomputer, a word processor, or even automobile ormicrowave oven controls. A typical microcomputer-oriented,finished-product design can incorporate total memory, withan address-space utilization of 16K to 64K bytes. Withhigh-volume manufacturing, the total package may cost aslittle as $100 to $500.

Over the past 25 years there has been a tremendousevolution in the functional capabilities of language systems.These systems need no longer be confined to "big" machines.Much of the improvement in function is becoming available inlanguage systems for microcomputers.

Yet, major manufacturers are still promoting their"super" micro assemblers/debuggers as the best software toolfor applications software of computer systems. Consequently,many programmers and designers continue to work withprimitive language tools.

This first BYTE-sponsored conference on languages andtools for microcomputing will introduce designers, systemsanalysts, implementers, and managers to various high levellanguages and associated systems tools that are becomingcommercially available. Knowledge of these recentdevelopments is absolutely essential to productive use ofmicrocomputer techology when that scarce resource,programmer/designer time, is being spread more and morethinly among a myriad of potential applications.

The conference will zero in on five specific high levellanguages because they are—or shortly willbecome—readily available for implementations with smallcomputers. Speakers will explore these languages and toolsfor programming in terms of their usefulness for practicalmicrocomputer applications.

Three of the featured languages are members of afamily of languages evolved from FORTRAN by way of Algol:Pascal, C, and Ada. These are most appropriate for uses inwhich documentation is as much a part of the designphilosophy as the achievement of a functional design itself.HAL/S, also in this family, will be discussed at the conferencein terms of the history of software tools used in the NASAspace-shuttle project's flight-control system design.Theselanguages share purposes with some of the more commoncommercial languages available on large computers, such asPL/I and COBOL.

Differing in philosophy and point of view—but alsocommercially available—are two other languages andcorresponding language concepts: LISP and FORTH. Each ischaracterized by a concept of language extensibility, which isimplemented in a highly interactive approach. The centraland dominant theme of LISP is one of list structures, whichmay be either data or program material. The concept of treestructures and relationships underlies LISP's usefulness in theartificial-intelligence milieu. FORTH has a central theme of astack-oriented processor, emulated as a threaded codeinterpreter, and an extensible library of operations that maybe defined beyond a basis set of standard primitives.

THE

PRQGFTO,

Introduction

Carl T. Helmers, Jr.

Editor-in-ChiefBYTE Magazine

Writing in high level languageshas numerous well-publicizedadvantages: programs are moreportable; they have superiorstructures; they are easier to writeand debug. At this first session ofthe conference, Carl Helmers willsurvey and define language sys-tems, analyze language systemsas complete tools, discuss theevolution of all high level lan-guages, and establish reasonswhy specific high level languagesare appropriate for microcom-puters.

The

Importanceof Tools

Dr. Fred H. Martin

Executive OfficerIntermetrics, Inc.

The use of software tools in thedevelopment of systems involvingcomputers is crucially important.Fred Martin, one of the designersof the HAL/S language, will re-view the advantages of high levellanguage techniques and auto-mated aids to programming fromthe point of view of his NASA ex-perience with HAL/S, developedspecifically to replace the ma-chine-dependent, low-level pro-gramming that plagued theApollo project. The crucial im-portance of high level languagesin reliable software design will bereviewed in the context of this sys-tem—in which a software crashcan literally lead to a pile of bro-ken parts on the ground.

The PascalPerspective

Peter Grogono

Analyst/ProgrammerConcordia University

The Pascal language is one of themost attractive alternatives in thesmall computerfield. It has stead-ily gained popularity in use onmachines as small as the Apple-II. Peter Grogono, the authorof Programming in Pascal, willprovide an introduction to thelanguage and discuss its use as amore powerful, more modular,more elegant solution to businessdata problems.

AfterPascal, What?

Dr. Kenneth L. Bowles

Director, Institute for

Information SystemsUniversity of California,

San Diego

While Pascal is an immenselyuseful language, it is not neces-sarily a panacea. Limitations ofthe language in areas of real timecontrol and handling of multipleconcurrent processes, in particu-lar, argue for a new look at thedesign of the language. KenBowles will introduce one evolu-tionary variant that will becomevery important over the next dec-ade—the Ada language, origi-nally designed for the Depart-ment of Defense. Microcomputerimplementations of this lan-guage, using machine-inde-pendenttechniques, will make itastrong alternative for program-ming microcomputer applica-tions systems.

Trees AndLists as Tools

Dr. Henry G. Baker, Jr.

Assistant ProfessorUniversity of Rochester

Not all programming problemsare amenable to convenient solu-tions using conventional block-structured, sequential languages.Many require representing com-plex heterogeneous objects andrelationships among those ob-jects. This approach is attractivefor selected applications: sym-bolic mathematical computation,computer-aided design, com-mercial integrated databases,English front-end processors,computer-aided manufacturing,robotics control, interactivegraphic systems, and interactiveintegrated circuit-design systems.

The LISP language offers theblock-structured control of Pas-cal, together with the friendly in-teractive nature of BASIC. In ad-dition, it offers lists and trees asdata structuring primitives and atireless "garbage collector" tokeep memory neat and clean.

Henry Baker will discuss the LISPlanguage and the kinds of auto-mated tools required to use it.

What is C?

John A. Morse

Principal Engineer,

Corporate ResearchDigital Equipment Corporation

The language C was originallydeveloped at Western Electric foruse as a tool for development ofthe UNIX operating system at BellLaboratories. Now that C com-pilers are starting to becomeavailable for microcomputer sys-

tems, this language becomes a vi-able alternative for both operat-ing system and applicationdevelopers. John Morse will givean overview of the language Cand will detail the types of appli-cations for which it is most appro-priate.

The ForthAlternatives

Charles H. Moore

Chairman of the BoardForth, Inc.

One viable and unconventionalapproach to programming is thehighly interactive languageFORTH, a language in which thefeature of extensibility is empha-sized. The typical implementationof FORTH is a highly integratedcombination of software devel-opment tools and programmingaids oriented toward a concep-tual stack machine with integersas the primitive data type. In anygiven application, unique exten-sions that fit into the matrix basiccore of the language are createdby the designer. Charles Moore,the inventor of FORTH, will dem-onstrate some of the more dy-namic uses of the language inreal-time applications.

^ElTIEITEEliTI

LANGUAGES

m

TQQLS

MCflaCQCTPlJTM:KBYTEi CONFERENCE

WllFUEtUI

Who

Should

Attend

Designers, systems analysts, imple-mented, and managers with an in-terest in holding down costs on theirsoftware projects. Fields with spe-cial applicability include electronicsand electronics design, automatedmanufacturing, scientific instrumen-tation design, and aerospace con-trol systems.

Circle 110 on inquiry card.

Tentative Schedule

June 16,

1980

8:00-

9:00 A.M.

9:00-10:00 A.M.

10:00-10:30 A.M.

10:30-12:00

P.M.

12:00-

1:30

P.M.

1:30-

3:00

P.M.

3:00-

3:15

P.M.

3:15-

4:45

P.M.

4:45-

5:15

P.M.

June 17, 1980

8:30-10:00 A.M.

10:00-10:30 A.M.

10:30-12:00 P.M.

12:00- 1:30 P.M.

1:30- 3:00 P.M.

3:00- 4:00 P.M.

REGISTRATION

INTRODUCTION: Carl Helmers

COFFEE INTERMISSION

THE IMPORTANCE OF TOOLS: Fred Martin

LUNCHEON

THE PASCAL PERSPECTIVE: Peter Grogono

COFFEE INTERMISSION

AFTER PASCAL, WHAT?: Ken Bowles

OPEN DISCUSSION

TREES AND LISTS AS TOOLS: Henry Baker

COFFEE INTERMISSION

THE FORTH ALTERNATIVE: Charles Moore

LUNCHEON

WHAT IS C?: John Morse

PANEL DISCUSSION: All speakers

To attend the Languages and Tools forMicrocomputing Conference, June 16-17, 1980, McGraw-Hill World Head-quarters in New York City, fill in thecoupon, or write on your company let-terhead to:

McGraw-Hill Conference &Exposition Center

1221 Avenue of the AmericasRoom 3677

New York, New York 10020Or call: 212/997-4930

Pleas* Print or Typo

Registration Fee: $485

□ Payment enclosed (Makecheck payable to McGraw-Hill Conference & ExpositionCenter)

□ Please bill me directly

□ Please bill company (Paymentdue prior to Conference)

□ This confirms my phone reser-vation

NAMETITLE -

First Name

COMPANYADDRESS

CITY

TELEPHONE (REGISTRANT'S SIGNATURE

Hotel Reservations: The New York Hilton (212-586-7000) is holding a block ofrooms up to three weeks prior to the Conference. For reservations, contact the hoteldirectly. Please be sure to identify the title and dates of the Conference for preferen-tial treatment.

Cancellation Liability: In the event of cancellation of the Conference for any rea-son, McGraw-Hill's liability is limited to the return of the registration fee.

Cancellation Policy: Confirmed registrants who cancel within FOURTEEN BUSI-NESS DAYS of the Conference are subject to a $100 service charge. Cancellationmust be received in writing. Confirmed registrants who fail to attend and do not can-cel prior to the Conference are liable for the entire registration fee. You may, if youwish, send a substitute.

WHAT WOULD YOU SAY TO

] [rw-w/j -i ■ j frrcrn kjah ;:«

FROM YOUR MICROCOMPUTER?

"YOU'RE TALKING OUR LANGUAGE:

PL I-80."

New PL/l-80 from Digital Research Brings Big ComputerProgramming Power to Microcomputer Systems.

PL/1-80 is the biggestnews for small systemusers and OEMs since weintroduced CP/AA® andMP/AA. PL/1-80 is ANSI'sGeneral Purpose Subset offull PL/1, tailored into alanguage for 8080, 8085and Z8C users who expectthe software revolutionthey've seen in hardware—better results at lowercost. PL/1-80 works harderthan any other general-purpose language forbusiness, science, re-search and education.

The PL/1-80 softwarepackage includes a na-tive code compiler, com-prehensive subroutinelibrary, linkage editor andrelocating macro assem-bler. And it's backed byourCP/MandMP/Moperating systems.

Best of all, the completePL/1-80 system disk-ette and documenta-tion costs just $500.

PL/1-80: There's nobetter way to get big-machine results from your8-bit processor.

Circle 111 on inquiry card.

Single-and Multi-User Operating SystemsThat Set Industry Standards.

CP/M is the industrystandard operatingsystem for small ma-chines. With thousandsof users throughout theworld, it's the most popu-lar and widely used. It'sthe original, hardware-independent 'bus' forusers working with abroad array of lan-guages, word-processingand applicationssoftware available fromscores of suppliers ataffordable prices.

Now we've made a greatCP/AAeven better. CP/AA2.2 is the latest release ofthe efficient, reliable sys-tem that's truly universal,able to manage virtuallyany 8080, 8085orZ80micro and its floppy orhard-disk subsystems.Named to the 1979Datapro Software HonorRoll, CP/M comes on adiskette with its ownoperating manual, forjust $150 in unitquantity.

' - - -

aaropro

&

%

SOFTWARE

HONORROLL

^

A*OlVTT(lS»*

MP/M provides big-computer power atsmall-computer cost. It

provides multi-terminalaccess with multi-programming at eachterminal. And it's CP/AAcompatible, so you canrun many programminglanguages, applicationspackages and develop-ment software on yoursystem.

Check these advancedcapabilities. Run editors,translators, word proces-sors and backgroundprint spoolers simulta-neously. Use AAP/AA'sreal-time facilities tomonitor an assembly lineand schedule programsautomatically, or controla network of micros. Evenwrite your own systemprocesses for operationunder AAP/AA. The pos-sibilities are endless, yetMP/M costs just $300(unit price for disketteand manual).

Utilities That WorkFor You.

Use our utilities. Thousands

do. They're designed to makeyour small system work extrahard, yet they cost surprisingly

little.:

• MAC™ (MacroAssembler)—$90.

• SID™ (Symbolic InstructionDebugger)—$75.

• ZSID™(Z80 Symbolic Instruc-tion Debugger)—$100.

• TEX (Text Formatter)—$75.

• DESPOOL™ (Background PrintUtility)—$50.

All are supplied on a diskette,with operating manual.

Digital Research

P.O. Box 579

801 Lighthouse Avenue

Pacific Grove, CA 93950

408 649-3896

TWX 910 360 5001

liOl DJGJTRl RESEARCH"

Order theprofessional's

choice.UCSD Pascal.

The Pascal everyone is talking about is UCSDPascal.. .with over 10,000 users and growing. Thefully developed Pascal is available with supportfrom a professional software company. Implementedon most major microprocessors.

Not just another compiler, but completedevelopment software — from operating system toscreen-oriented editor. Language extensions forsystems development and commercial applicationsprogramming.

Program portability that allows programs writtenon one microcomputer to run without recompilationon different microcomputers. This protects yoursoftware investment... without restricting yourhardware options.

If you have CP/Mf visit your local computerstore or order below. System supplied on single-density, soft-sectored, 8" floppy disks and requires48K of contiguous RAM. For other systems callus or write for more information. Telephone ordersaccepted with Master Charge or VISA.

rnicnosvsTems

R SUBSIOIPIFIV OF SOFTECH

9494 Black Mountain Road • San Diego • CA • 92126TEL: (714) 578-6105 • TWX: 910-335-1594

CP/M is a registered trademark of Digital Research Corporation. LSI-11 is atrademark of Digital Equipment Corporation. UCSD Pascal is a trademark of theRegents of the University of California.

□ Yes! Rush me a complete UCSD Pascal systemfor my CP/M® based microcomputer. A checkor money order for $300.00 is enclosed. I havea computer.

□ Send me more information about UCSD Pascal.Versions are available for systems using thefollowing microprocessors: LSI-11™ 6502, 6800,6809, 9900, Z80 and 8080/8085.

□ Send me only the complete set of documentationfor UCSD Pascal. A check or money order for$37.00 is enclosed.

□ Send distributor information.

Name

Company , ■■. _j»—

Address

City

State/Zip

M/C or VISA # Exp. Date

Mass. and Calif, residents enclose applicable sales tax. B-5

Programming Quickies

Decisions, Decisions

Geoffrey Gass, 5240 SW Dosch Rd, Portland OR 97201

Frequently, a program has to select one of two positiveactions as the result of a test (eg: print a " + " or a " —"after checking the sign of a number).

Conventionally, it might be done in a skip chain likethis 6800 code:

SGN

TST NUMB

Make the test.

BMINEG

One course if negative.

LDA A #' +

The other course if positive.

BRA PRINT

Watch out — don't run into NEG

NEG

LDAAjT-

Minus sign for negative number.

PRINT

JSR OUTPUT

Back together again; print thesign.

It's awkward, running into yourself like that. Here ishow to avoid the awkwardness and save a couple ofbytes:

SGN

PRINT

LDA A #' +

Set up for one course in advance

TST NUMB

Then make the test.

BPL PRINT

Confirming advance choice.

LDA A #' -

Change course if advance choice

wrong.

JSR OUTPUT

Print the proper sign.

The bytes saved (if not otherwise needed) can be usedafter the TST NUMB to BEQ (branch on accumulatorequal to 0) past the PRINT routine if the number is zero,so 0 will be output without a sign, assuming we are deal-ing with a 1-byte number. ■

Formatted ProgramOutput for the KIM-1

Lawrence A Ezard, PhD, Associate Professor of Engineering,Pennsylvania State University, Capitol Campus,Middletown PA 17057

Here is a short program that might be useful for ownersof the MOS Technology KIM-1 system. It can be used tofind bugs, and to print out and document programs.

The flowchart in figure 1 illustrates the algorithmutilized. This program will examine the contents of pro-grammable memory and print the program instructionsfound there. The output is in a format of address, oper-ation code, and operand. The user specifies the startingand stopping addresses to be examined by storing valuesin the appropriate locations. At the end of its execution,the program returns control to the KIM monitor.

In writing the program, I made use of the fact that,with three exceptions, the least significant digit (in hexa-

190 May 1980 © BYTE Publications Inc

Circle 112 on inquiry card.

MORE COLOR. MORE SOUND.MORE PERSONAL/RUSINESS POWER.

ATARI 820 Primer. Highresolution, dot-main* printerkeeps a permaneof your programs) and /tnetr resits jp

Otsfcettes (not shown).

Sundays S'"4 «ch aute.

ATARI 800 Personal Coniputer,Easy to operate. Easier to own.This is wham the age of thepersonal computer

.Joystick, paddle anddriving coniroJIers. Let you..direct the acton m sometrf #te most oUaSenoJnacompute* games you haveever played

jfrrn

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"Attn pfe-t«co«*ed casseae tape

programs. In «w*d« range otsublets, (rom computerized study!o small business management

ATARI 410 Prog»Recorder, lets you writeand s^re your own

Computer torSio! keyboard, FuN57 toy, Operates i*e aneiectrootc typewriter to give you

a^nanumersc and grapftie

Enpandabto merowy. M 8K Of18K Mummy Moa«t»'*i

TWiilt of the possibilities.

Compare the built-in features ofleading microcomputers with theAtari personal computers. And goahead, compare apples andoranges. Their most expensiveagainst our least expensive: theATARI® 400™.

Start with graphics capabilities.The ATARI 400 offers 128 colorvariations. 16 colors in 8luminance levels. Plus 29keystroke graphics symbols and 8graphics modes. All controlledfrom a full 57 key ASCII keyboard.With upper and lower case. Andthe system is FCC approved with abuilt-in RF modulator. That's justfor openers.

Now, compare sound capabili-ties. Four separate sound channelsand a built-in speaker. With theoptional audio/digital recorder,you can add Atari's unique Talk &Teach™ Educational Systemcassettes.

Here's the clincher: Solid state(ROM) software. For homemanagement, business and enter-tainment. Or just plug in an Atari10K BASIC or Assembler languagecartridge and the full power of thecomputer is in your hands.

Memory? 8K expandable to 16K.And that's just for the ATARI 400at a suggested retail of only$599.99.

The ATARI® 800™ gives you allthat and much more.

User-installable memory to 48K.A full-stroke keyboard.

With a high-speed serial I/O portthat allows you to add a wholefamily of smart peripherals.Including up to four individuallyaccessible disk drives. And a highspeed dot-matrix impact printer.And, the Ata'ri Program Recorderis included with the 800 system.Suggested retail price for theATARI 800 (including recorder) is$999.99.

Make your own comparisonwherever personal computers aresold.

Or, send for a free chart thatcompares the built-in features ofthe ATARI 400 and 800 to otherleading personal computers.

Atari promises to be the most popular Personal Computer System of the1980's! Feel free to contact us for Atari literature.

1

NEECO

679 Highland Ave.Needham, MA02194

Customer Sales:NEECO

679 Highland Ave.(617) 449-1760

Circle 114 for NEECO

Needham, MA 02194

Dealer Sales:Microamerica Distributing

21 Putnum St., Needham, MA 02194(617)449-4310

Circle 113 for microamerica

BYTE May 1980 191

decimal) of 1-byte op codes is always 8 or A. Also, withnine exceptions, the least significant digit of 3-byte opcodes is always C, D, or E.

Listing 1 was produced by the program. The labels,

source code mnemonics, and comments were added later.The program uses several subroutines from the KIM-1monitor: CRLF, PRTPNT, OUTSP, PRTBYT, and

INCPT. ■

Listing 1: Program in 6502 code to print out hexadecimal instruction codes from KIM-1 memory. Before running the program, do thefollowing. Load the starting address for examination in locations 17F5 (SAL, low-order) and 17F6 (SAH, high-order). Load the endingaddress plus 1 in locations 17F7 (EAL, low-order) and 17F8 (EAH, high-order). Clear the decimal mode by entering 00 in location00F1. The starting address for execution is hexadecimal 0301. The memory used is 0300 to 03D0.

Hexadecimal

HexadecimE

ll

Address

Code

0300

0301

AD

F5

17

0304

85

FA

0306

AD

F6

17

0309

85

FB

030B

20

2F

1E

030E

20

1E

1E

0311

20

9E

1E

0314

20

9E

1E

0317

A2

00

0319

A1

FA

031B

8D

00

03

031E

C9

00

0320

F0

15

0322

C9

40

0324

F0

11

0326

C9

60

0328

F0

0D

032A

29

OF

032C

C9

08

032E

F0

07

0330

C9

0A

0332

F0

03

0334

4C

40

03

0337

AD

00

03

033A

20

3B

1E

033D

4C

B7

03

0340

AD

00

03

0343

C9

19

0345

F0

31

0347

C9

39

0349

F0

2D

034B

C9

59

034D

F0

29

034F

C9

79

0351

F0

25

0353

C9

99

0355

F0

21

0357

C9

B9

0359

F0

1D

035B

C9

D9

035D

F0

19

035F

C9

F9

0361

F0

15

0363

C9

20

0365

F0

11

0367

29

OF

0369

C9

OC

036B

F0

0B

036D

C9

0D

036F

F0

07

0371

C9

0E

0373

F0

03

0375

4C

A1

03

0378

AD

00

03

037B

20

3B

1E

037E

20

9E

1E

0381

20

9E

1E

0384

20

63

1F

0387

A2

00

0389

A1

FA

038B

20

3B

1E

038E

20

9E

1E

0391

20

9E

1E

0394

20

63

1F

0397

A2

00

0399

A1

FA

039B

20

3B

1E

039E

4C

B7

03

03A1

AD

00

03

Label

Op Code

Operand

Comments

TEMPI

LDA

SAL

Load starting address in POINTL

STA

FA

and POINTH

LDA

SAH

STA

FB

START1

JSR

CRLF

Do carriage return and line feed

JSR

PRTPNT

Print starting address

JSR

OUTSP

Print 2 spaces

JSR

OUTSP

LDX

#$00

LDA

(FA,X)

Load Contents of address at FB,

STA

TEMPI

CMP

#$00

Decide if Op Code is 1 byte

BEQ

PRNT1

CMP

#$40

BEQ

PRNT1

CMP

#$60

BEQ

PRNT1

AND

#$0F

CMP

#$08

BEQ

PRNT1

CMP

0A

BEQ

PRNT1

If not 1 byte

JMP

B3

Jump to test for 3-byte Op Code

PRNT1

LDA

TEMPI

Print 1-byte Op Code

JSR

PRTBYT

JMP

INCAD

Jump to increment address

B3

LDA

TEMPI

Test for a 3-byte Op Code

CMP

#$19

BEQ

PRNT3

CMP

#$39

BEQ

PRNT3

CMP

#$59

BEQ

PRNT3

CMP

#$79

BEQ

PRNT3

CMP

#$99

BEQ

PRNT3

CMP

#$B9

BEQ

PRNT3

CMP

#$D9

BEQ

PRNT3

CMP

#$F9

BEQ

PRNT3

CMP

#$20

BEQ

PRNT3

AND

#$0F

CMP

OC

BEQ

PRNT3

CMP

#$0D

BEQ

PRNT3

CMP

#$0E

BEQ

PRNT3

JMP

PRNT2

GOTO print 2 bytes

PRNT3

LDA

TEMPI

Print 3 bytes

JSR

PRTBYT

Print Op Code

JSR

OUTSP

Space

JSR

OUTSP

JSR

INCPT

Increment address

LDX

#$00

Load contents of address

LDA

(FA,X)

at FBFA

JSR

PRTBYT

Print Operand

JSR

OUTSP

JSR

OUTSP

JSR

INCPT

Increment address

LDX

#$00

Load contents of address

LDA

(FA,X)

at FBFA

JSR

PRTBYT

Print Operand

JMP

INCAD

PRNT2

LDA

TEMPI

Print 2 bytes

Listing 1 continued on page 194

192 May 1980 © BYTE Publications Inc

By Netronlcs

ASCII/BAUDOT,STAND ALONE

Computer $1AQTerminal 1W

The Netronics ASCII/BAUDOT Computer Terminal Kit is amicroprocessor-controlled, stand alone keyboard/terminalrequring no computer memory or software. It allows the use ofeither a 64 or 32 character by 16 line professional display for-mat with selectable baud rate, RS232-C or 20 ma. output, fullcursor control and 75 ohm composite video output.

The keyboard follows the standard typewriter configurationand generates the entire 128 character ASCII upper/lower caseset with 96 printable characters. Features include onboardregulators, selectable parity, shift lock key, alpha lock jumper,a drive capability of one TTY load, and the ability to matedirectly with almost any computer, including the new Ex-plorer/85 and ELF products by Netronics.

The Computer Terminal requires no I/O mapping andincludes Ik of memory, character generator, 2 key rollover,processor controlled cursor control, parallel ASCII/BAUDOTto serial conversion and serial to video processing—fullycrystal controlled for superb accuracy. PC boards are thehighest quality glass epoxy for the ultimate in reliability andlong life.

VIDEO DISPLAY SPECIFICATIONS

The heart of the Netronics Computer Terminal is the micro-processor-controlled Netronics Video Display Board (VID)which allows the terminal to utilize either a parallel ASCII orBAUDOT signal source. The VID converts the parallel data toserial data which is then formatted to either RS232-C or 20 ma.current loop output, which can be connected to the serial I/Oon your computer or other interface, i.e.. Modem.

When connected to a computer, the computer must echo thecharacter received. This data is received by the VID whichprocesses the information, converting to data to video suitableto be displayed on a TV set tusing an RF modulator) or on avideo monitor. The VID generates the cursor, horizontal andvertical sync pulses and performs the housekeeping relative towhich character and where it is to be displayed on the screen.

Video Output: 1.5 P/P into 75 ohm (EIA RS-170) • Baud Rate:IWand300 ASCII• Outputs: RS232-Cor20ma. current loop• ASCII Character Set: 128 printable characters—

! ■t$3il,()**,-./0123456789: ;<->?WB(»EF(iMI3KUtCP«STUUyXVZC\]\xabcdtf9hUklAnonrstuwxyz{iHI

BAUDOT Character Set: A B C D E FG HI JKLMNOPQRSTUVWXYZ-?:*3$ti().,90}4!57;2/68»Cursor Modes: Home, Backspace, Horizontal Tab, Line Feed,Vertical Tab, Carriage Return. Two special cursor sequencesare provided for absolute and relative X- Y cursor addressing •Cursor Control: Erase, End of Line, Erase of Screen, FormFeed, Delete * Monitor Operation: 50 or 60Hz (jumperselectable.

Continental U.S.A. Credit Card Buyers Outside Connecticut

CALL TOLL FREE 800-243-7428

To Order From Connecticut Or For Technical ^m wmr Assistance, Etc. Call (203) 354-9375

I Netronics R&D Ltd., Dept. PE-9333 Litchfield Road, New Milford, CT 06776

| Please send the items checked below—

ID Netronics Stand Alone ASCII Keyboard/ComputerTerminal Kit, $149.95 plus $3.00 postage & handling.ID Deluxe Steel Cabinet for Netronics Keyboard/Termi-nal In Blue/Black Finish, $19.95 plus $2.50 postageI and handling.D Video Display Board Kit alone (less keyboard), $89.95

I plus $3 postage & handling.D 12" Video Monitor (10 MHz bandwidth) fully assem-Ibled and tested, $139.95 plus $5 postage and handling,□ RF Modulator Kit (to use your TV set for a monitor),

I $8.95 postpaid.D 5 amp Power Supply Kit In Deluxe Steel CabinetI(±8VDC @ 5 amps, plus 6-8 VAC), $39.95 plus $2postage & handling.I Total Enclosed (Conn. res. add sales tax) $__ ,By-

ID Personal Check D Cashiers Check/Money OrderD Visa D MasterCharjie(Bankfl__ )

I

- Signature.

I Print

■ Name

I

City.

L__

IIIIIIIIIIIIIIII

D Send Me More Information ^m j^ J

_Exp. Date .

.Zip

Start Computing For Just $129.95 With An8085-Based Professional Computer Kit—

Explorer/85

100% compatible with all 8080A and8085 software & development tools!

No matter what your future computing plans maybe, Level "A "—at $129.95—is your starting point.

Starting at just $129.95 for a Level "A " operating system,you can now build the exact computer you want. Explorer/85can be your beginner's system, OEM controller, or IBM-formatted 8" disk small business system.. .yet you're neverforced to spend a penny for a component or feature you don 7want and you can expand in small, affordable steps!

Now, for just $129.95, you can own the first level of a fullyexpandable computer with professional capabilities—a com-puter which features the advanced Intel 8085 cpu, therebygiving you immediate access to all software and developmenttools that exist for both the 8085 and its 8080A predecessor(they are 100% software compatible)—a computer whichfeatures onboard S-100 bus expansion—plus instant conver-sion to mass storage disk memory with cither 5-1/4'* diskettesor standard IBM-formatted 8" disks.

For just $129.95 (plus the cost of a power supply, keyboard/terminal and RF modulator, if you don't have them already),Explorer/85 lets you begin computing on a significant level...applying the principles discussed in leading computer maga-zines. . .developing "state of the art" computer solutions forboth the industrial and leisure environment.Level "A" Specifications

Explorer/85's Level "A" system features the advanced Intel8085 cpu, an 8355 ROM with 2k deluxe monitor/operatingsystem, and an 8155 ROM-1/O—all on a single motherboardwith room for RAM/ROM/PROM/EPROM and S-100 ex-pansion, plus generous prototyping space.

(Level "A" makes a perfect OEM controller for industrial

applications and is available in a special Hex Version which

ew||^U § can be programmed using

jw If the Netronics Hex Keypad/

IT. ...ft&~:,: Display.)

X;f- PC Board: glass epoxy, plated

X*~- through holes with solder mask

r' ■■ • I/O: provisions for 25-pin

(DB25) connector for terminalserial I/O, which can also sup-port a paper tape reader.. .provision for 24-pin DIPsocket for hex keyboard/dis-play. . .cassette tape recorder in-put. . .cassette tape recorder output.. .cassette tape controloutput.. .speaker output... LED output indicator on SOD(serial output) line,. .printer interface (less drivers).. .total offour 8-bit plus one 6-bit I/O ports-Crystal Frequency: 6.144MHz • Control Switches: reset and user (RST 7.5)interrupt.. .additional provisions for RST 5.5, 6.5 and TRAPinterrupts onboard • Counter/Timer: programmable, 14-bitbinary • System RAM: 256 bytes located at F800, ideal forsmaller systems and for use as an isolated stack area inexpanded systems... RAM expandable to 64k via S-100 bus or4K on motherboard.

System Monitor (Terminal Version): 2k bytes of deluxesystem monitor ROM located at F000 leaving 0000 free for userRAM/ROM. Features include tape load with labeling .. .tapedump with labeling.. .examine/change contents of memory...insert data... warm start. . .examine and change allregisters, . .single step with register display at each break point,a debugging/training feature...go to execution address...move blocks of memory from one location to another.. .fillblocks of memory with a constant... display blocks of memory.. .automatic baud rate selection.. .variable display line lengthcontrol (1-255 characters/line).. .channelized I/O monitorroutine with 8-bit parallel output for high speed printer...serial console in and console out channel so that monitor cancommunicate with I/O ports.

System Monitor (Hex Version): Tape load with labeling...tape dump with labeling... examine/change contents of mem-ory...insert data. ..warm start. ..examine and change all

By Netronics

Level "A" at S 129.95 is acomplete operating system,perfect for beginners, hob-biests, or industrial con-troller use.

Explorer/85 with"C" card cage.

R&DLtoT, KpTWnJTeld Road. New Milford, C"

Netronics333 Litchfield

Please send the items checked below—D Explorer/85 Level "A" Kit (ASCIIVersion), $129.95 plus $3 p&h.D Explorer/85 Level "A" Kit (HexVersion), $129.95 plus $3 p&h.D 8k Microsoft BASIC on cassettetape, $64.95 postpaid.D 8k Microsoft BASIC in ROM Kit(requires Levels "B," "D," and "E"),$99.95 plus $2 p&h.

D Level "B" (S-100) Kit, $49.95 plus$2 p&h.

D Level "C" (S-100 6-card expander)Kit, $39.95 plus $2 p&h.D Level "D" (4k RAM) Kit, $69.95plus $2 p&h.

D Level "E" (EPROM/ROM) Kit,$5.95 plus 50« p&h.

D Deluxe Steel Cabinet for Explorer/85, $49.95 plus $3 p&h.D ASCII Keyboard/Computer Ter-minal Kit (features a full 128 characterset, upper & lower case, full cursor con-trol, 75 ohm video output convertibleto baudot output, selectable baud rate,RS232-C or 20 ma. I/O, 32 or 64 char-acter by 16 line formats, and can beused with either a CRT monitor or a TVset (if you have an RF modulator),$149.95 plus $2.50 p&h

registers.. .single step with register display at each break point.. .go to execution address. Level "A" in the Hex Versionmakes a perfect controller for industrial applications and canbe programmed using the Netronics Hex Keypad/Display.

Hex Keypad/DisplaySpecifications

Calculator type keypad with 24system defined and 16 userdefined keys. 6 digit calculatortype display which displays fulladdress plus data as well asregister and status information.

Level "B" Specifications

Level"B" provides the S-100 signals plus buffers/drivers tosupport up to six S-100 bus boards and includes: addressdecoding for onboard 4k RAM expansion select-able in4k blocks.. .address decoding for onboard 8k EPROM expan-sion selectable in 8k blocks.. .address and data bus drivers foronboard expansion... wait state generator (jumper selectable),to allow the use of slower memories.. .two separate 5 voltregulators.

Level "C" Specifications

Level "C" expands Explorer'smotherboard with a card cage,allowing you to plug up to sixS-100 cards directly into themotherboard. Both cage and« cards are neatly contained insideExplorer's deluxe steel cabinet.Level "C" includes a sheet metal superstructure, a 5-card goldplated S-100 extension PC board which plugs into the mother-board. Just add required number of S-100 connectors

Level "D" Specifications

Level "D" provides 4k or RAM, power supply regulation,filtering decoupling components and sockets to expand yourExplorer/85 memory to 4k (plus the original 256 bytes locatedin the 8155A). The static RAM can be located anywhere from0000 to EFFF in 4k blocks.Level "E" Specifications

Level "E" adds sockets for 8k of EPROM to use the popularIntel 2716 or the Tl 2516. It includes all sockets, power supplyregulator, heat sink, filtering and decoupling components.Sockets may also be used for soon to be available RAM IC's(allowing for up to 12k of onboard RAM).

Order A CoordinatedExplorer/85 Applications Pak!

Experimenter's Pak (SAVE $12.50)—Buy Level "A" and HexKeypad/Display for $199.90 and get FREE Intel 8085 user'smanual plus FREE postage & handling!Student Pak (SAVE $24.45)—Buy Level "A," ASCII Key-board/Computer Terminal, and Power Supply for $519.85 andget FREE RF Modulator plus FREE Intel 8085 user's manualplus FREE postage & handling!

Engineering Pak (SAVE $41.00)—Buy Levels "A," "B,""C," "D," and "E" with Power Supply, ASCII Keyboard/Computer Terminal, and six S-100 Bus Connectors for $514.75and get 10 FREE computer grade cassette tapes plus FREE8085 user's manual plus FREE postage & handling!Business Pak (SAVE $89.95)—Buy Explorer/85 Levels "A,""B," and "C" (with cabinet), Power Supply, ASCII Key-board/Computer Terminal (with cabinet), 16k RAM, 12"Video Monitor, North Star 5-1/4" Disk Drive (includes NorthStar BASIC) with power supply and cabinet, all for just$1599.40 and get 10 FREE 5-1/4" minidiskettes ($49.95 value)plus FREE 8085 user's manual plus FREE postage & handling!

Continental 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 "1

sonalized disk operating system—justj

plug it in and you're up and running!), I

$699.95 plus $5 p&h.

□ Power Supply Kit for North Star!

Disk Drive, $39.95 plus $2 p&h.

D Deluxe Case for North Star Disk!

Drive, $39.95 plus $2 p&h.

D Experimenter's Pak (see

$199.90 postpaid.

D Student Pak (see above),

postpaid.

D Engineering Pak (see

$514.75 postpaid.

D Business Pak (see above), $1599.401

postpaid. .

Total Enclosed $ I

CT 06676

plus $2 p&il.

D Deluxe Steel Cabinet for ASCIIKeyboard/Terminal, $19.95 plus $2.50p&h.

D Power Supply Kit (± 8V @ 5 amps)in deluxe steel cabinet, $39.95 plus $2p&h.

D Gold Plated S-100 Bus Connectors,$4.85 each, postpaid.D RF Modulator Kit (allows you touse your TV set as a monitor), $8.95postpaid.

D 16k RAM Kit (S-100 Board expandsto 64k), $199.95 plus $2 p&h.Q 32k RAM Kit, $329.95 plus $2 p&h.D 48K RAM Kit, $459.95 plus $2 p&h.D 64k RAM Kit,«589.95 plus $2 p&h.D 16k RAM Expansion Kit (to expandany of the above up to 64k), $139.95plus $2 p&h each.

C Intel 8085 cpu User's Manual, $7.50postpaid.

D Special Computer Grade CassetteTapes, $1.90 each or 3 for $5, postpaid.□ 12" Video Monitor (10 MHz band-width), $139.95 plus $5 p&h.D North Star Double Density FloppyDisk Kit (One Drive) for Explorer/85 (includes 3 drive S-100 controller

above), I$319.851

above), |

(Conn. res. add sales tax) By—

D Personal Check □ M.O./Cashier's I

Check □ Visa □ Master Charge ■

(Bank#_

)■

Signature _PrintName

_Exp. Date _

City.

3 Hex Keypad/Display Kit, $69.95 °OS, and extended BASIC with per- State

_Zip_

D Send Me Information

—J

Circle 115 on inquiry card.

Circle 116 on inquiry card.

BYTE May 1980 193

Listing

1 continuei

i:

03A4

20

3B

1E

JSR

PRTBYT

Print Op Code

03A7

20

9E

1E

JSR

OUTSP

Space

03AA

20

9E

1E

JSR

OUTSP

03AD

20

63

1F

JSR

INCPT

Increment address

03B0

A2

00

LDX

#$00

Load contents of

03B2

A1

FA

LDA

(FA,X)

address at FBFA

03B4

20

3B

1E

JSR

PRTBYT

Print Operand

03B7

20

63

1F

INCAD

JSR

INCPT

Increment to next Op Code

03BA

A5

FB

LDA

FB

Address

03BC

CD

F8

17

CMP

EAH

03BF

F0

03

BEQ

NEXT

03C1

4C

OB

03

JMP

START1

If this address is

03C4

A5

FA

NEXT

LDA

FA

equal to the ending

03C6

CD

F7

17

CMP

EAL

address then stop

03C9

FO

03

BEQ

STOP

Otherwise go to START1

03CB

4C

OB

03

JMP

START1

and print the Op Code

03CE

4C

4F

1C

STOP

JMP

START

f START J

LOAD STARTINGADDRESS INTOPOINTL ANDPOINTH

DO CARRIAGERETURN, LINE FEED,PRINT ADDRESS,SPACE

I

JC

LOAD OP CODESTORE IN TEMP 1

I 1

-H START1 030B II I

LOCATION

0319

PRINT OP CODEAND TWO BYTEOPERAND

I 1

I INCAD 03B7 (-

I I

I 1

—| PRNT3 0378 |I I

PRINT OP CODEAND OPERAND

I 1

—| PRNT2 03A1 |

I I

V

I 1

I STOP 03CE I—I I

/^REENTER *N \ JMp 1C4F^ MONITOR J J _____

Figure 1; Flowchart of procedure used to print hexadecimal instruction codes from KIM-1 memory.

194 May 1980 © BYTE Publications Inc

Until now,

computer graphics suffered

fi^ terminal highcost

[f you've ever considered displaying*Tektronix* graphics data from a hostcomputer, you know all about terminalhigh cost. A hunk of hardware like aTeklronix 4010 graphics terminal canset you back quite a few kilobucks. It'senough to drive a person of modestmeans to the drafting table.

The Affordable Alternative

ABW Corporation has just madegraphics display as practical as thepersonal computer. With TEKSIM. TheApple 11/Tektronix 4010 Simulator.TEKSIM is a read-only memory (ROM)that plugs directly into an inexpensiveApple II* computer Combining anadvanced programming techniqueknown as distributed processing withApple's high resolution plottingcapabilities enables TEKSIM to emulateTektronix 4010-series terminals at atract ion of the cost. (A symbolic represen-tation of TEKSIM inoperation is providedbelow lor the technically minded.)

Outstanding Features

The TEKSIM-Apple combinationfunctions in the same way as a Tektronixterminal, displaying graphical outputfrom a host computer without anymodification to the host-residentprogram. You can also input data to thehost using game paddles or a joystick.And a TEKSIM-Apple terminal even hasfeatures not available in the 4010-series.Six-color "palette" for multicoloreddisplays. Selective erase. Video outputto allow any size television to serve asthe screen. Plus the added benefits of apowerful Apple II computer to use bothin and out of graphics mode. Anycompromise? Just one. Apple's resolu-tion is about a fourth that ofaTektronixterminal. Still more than adequate formost applications.

Best Buy for Business; EducationTEKSIM is the logical choice for cor-porations and educators. A Tektronixterminal can be too much for a limited

budget. And investing in TEKSIM-Appleterminals will make any budget —bigor small —go a lot further.

Except tonal perfonnance. Affordableprice. That's TEKSIM, from ABWAt $795f.TEKSIM marks the end ofterminal high cost.

For more TEKSIM information,

mail this coupon to:ABW CorporationP.O. Box M 1047Ann Arbor, MI 48106

Or call (313) 971-9364.

Name

Position

Company

Address

City State

Please contact me. Phone.

JAp-

l_.

Dealer inquiries invited.

10050

How's how TEKSIM works: First. Tektronix data Then TEKSIM transforms it into Apple data..,comes out of the host computer:

...so it ran be displayed on the Apple'sTV screei i

1eKsim

APPLE D/TEKTR0NIX4010 SIMULATOR

H979 by ABW Corp."Tektronix ts a registered trademark ol Teklronix. fnc

Apple II is a registered trademark ot Apple Computer IncTMtgr s suggested retail price Quantity discounts available

ABW Corp. is not affiliated with, and TEKSIM is nol endorsed by,

Tektronix. Inc.

JBN

CORPORATION

Circle 117 on inquiry card.

BYTE May 1980 195

Give Your Computeran Ear for Names

Tom Munnecke

c/o Metasystems

6199 Shaker Dr

Riverside CA 92506

One of the major criticisms of thecomputer is that it is too literal (ie:unable to accept minor errors fromfallible human operators). When thecomputer asks a question, if ananswer is not exactly right the com-puter rejects it, even if the answer wasnearly correct. The computer doesnot apply a human's reasoning ability

Name

Code

Munnecke

M520

Minnecke

M520

Munnuke

M520

Munneake

M520

Munneeke

M520

MunickyMuneeck

M520M520

MonkeyMuneick

M520M520

Munnick

M520

Monnecks

M521

Muuncake

M522

Munnedie

M530

Lunnecke

L520

Munnecle

M524

Euler

E460

Gauss

G200

Hilbert

H416

Knuth

K530

LloydLukasiewicz

L300L222

Smith

S530

SmythSmytheSmittyGonzales

S530S530S530G524

Gonzalez

G524

Table 1: Sample

Soundex code for

several names.

The

first fourteen

names following

th

2 author's are

misspellings of

-lis

name, actually

found on mail,

along with their

respective Soundex

codes. Notice

that most of the

misspellings reduce

to the same Soundex

code and could

identify the correct name.

to determine the intent of theoperator. Instead, it works only withthe exact response.

There is a technique which hasbeen used since the turn of thetwentieth century to retrieve namesbased on pronunciation, rather thantheir spelling. It is called the Soundexcode, and was originally developed tosearch for names in the 1890 censusfiles. The technique is to give eachname a four-character code, con-sisting of the first letter of the lastname followed by three digitsrepresenting the sounds found in therest of the name. This code is thenused to group together all nameswhich "sound like" each other.

The Soundex code allows the userto enter a name in a form believed tobe the proper spelling. The computerresponds with a menu listing allsound-alike names, allowing the userto make a selection. If only one nameis found, the computer could con-firm the name identity and proceed.

For example the user could

Letters

b,f,p,v

c,g,j,k,s,x,z

d,t

I

m,n

r

Code Digit

123456

Table 2: Numeric single-digit codesthat are assigned to letters from thecorresponding groups as they occurin a name being encoded in theSoundex system.

misspell "Gonzales" as "Gonzalez";"Smythe" as "Smith"; or "Andersen"as "Anderson." I amparticularly sen-sitive to this problem because myname (loosely pronounced "money-key") is regularly misspelled. Table 1shows a sample of the misspellings, ascollected from actual mail I havereceived during the last two years.

The exact use of the Soundex codevaries greatly with the computer'sfile-management system. Some data-base management systems supportSoundex codes directly; others re-quire the programmer to structure thesearch logic. The program is easilymodified to arrange sounds in groupsother than as shown. Therefore, thereare many modified versions of thistechnique in use around the countryto account for local variations innames and programmer's whims.

The user might see the Soundexroutine working as follows (user in-put is italicized):

WHAT NAME: SMITHSELECT ONE:

1. Smith, Jack 123 Main St

2. Smith, John 456 Central St

3. Smythe, Zachary789 First AveEnter Choice:

If there is only one name with thesound, the computer might respond:

WHAT NAME: SMITHJohn Smith, 123 Main St

This approach is only the most simpletechnique. It can be enhanced by add-ing the first initial of the first name,sex, birthdate, or other characteristic

196 May 1980 © BYTE Publications Inc

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BYTE May 1980 197

Listing 1: Soundex program written in Microsoft BASIC for the Commodore PET. Table 3 describes variables used in the program.

100 REM TEST DRIVER FOR SOUNDEX

110 INPUT "LAST NAME":N$

120 GOSUB 2000:REM EXECUTE SUBROUTINE

130 PRINT "SOUNDEX CODE =";S$

140 GOTO 100

2000 REM SOUNDEX ROUTINE TOM MUNNECKE 2/22/79

2010 REM RETURNS SOUNDEX CODE S$ FROM LAST NAME N$

2020 REM SEE KNUTH, "ART OF COMPUTER PROGRAMMING", VOL §3, P 391

2030 REML$ = " ": REM LAST SOUND

2040 S$ = MID$(N$,1,1):REM START WITH FIRST LETTER OF NAME

2050 IF LEN(N$) < 2 THEN 2200:REM SKIP SHORT NAMES

2060 FOR I = 2 TO LEN (N$):REM FOR EACH REMAINING LETTER

2070 E$ = MID$(N$,I,1):REM SELECT I-TH LETTER

2080 E = ASC(E$)-64:REM CONVERT A THRU Z TO NUMBER 1 THRU 26

2090 IF E > 26 OR E < 1 THEN 2160:REM USE ONLY LETTERS

2095 REM SELECT SOUNDEX CODE

2100 K$ = MID$("0 123012002245501262301 0 2 0 2",E,1)

2110 REM ABCDEFGHIIKLMNOPQRSTUVWXYZ

2120 IF K$ = L$ OR K$ = "0" THEN 2160:REM SKIP TWO CONTIGUOUS SOUND-ALIKES

2140 S$ = S$ + K$:REM BUILD UP SOUNDEX RESULT

2150 IF LEN(S$)> 3 THEN 2200:REM ONLY FIRST 4 SOUNDS

2160 L$ = K$:REM SAVE LAST SOUND

2170 NEXTrREM DO NEXT CHARACTER IN NAME

2200 S$ - LEFT$(S$ + "000",4):REM PAD TO RIGHT WITH ZEROS AND SHORTEN TO 4 CHARS

2210 RETURN

2999 END

to identify the person with greateraccuracy.

Constructing the Soundex Code

The technique for constructing theSoundex code is found on page 391 of

The Art of Computer Programming,Volume 3: Sorting and Searching by

Donald Knuth (published byAddison-Wesley, Reading MA). Thefour steps in generating a Soundexcode are:

1. Retain the first letter of thename, and drop all occurrencesof a,e,i,o,u,w,y,h and q in

other positions.

2. Assign group numbers to the re-maining letters after the first ac-cording to the scheme given intable 2.

3. If two or more letters with thesame code are adjacent in theoriginal form of the name

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198 May 1980 © BYTE Publications Inc

Basic in A Nutshell

Name: Step-By-StepVendor: Program Design, Inc., 11Ida'r Court, Greenwich CT 06830Price: $49.95

Purpose: Teaches how to programa TRS-80 using BASICDocumentation: OutstandingLoading: OK-Level 6, not criticalImplementation: This is a case ofa BASIC program that teaches BA-SIC programming. It starts out withthe assumption that the studentonly knows how to turn the TRS-80on. Three cassette tapes aremounted in the cover of a loose-leaf notebook that also containssupplementary information frames.The course is divided into ten two-part lessons. From a simple PRINT"HI" through arrays and graphics tocomplex programs, all of the LevelII commands and statements areexercised.

The Instruction method consists ofexplanation, example, trial andtesting. Commands and state-ments are presented and ex-plained, examples are shown bothon the screen and in the notebook,and then the student is presentedwith some problems to solve usingthe BASIC elements under discus-sion. If an Incorrect answer is given,

two more tries are allowed, andthen the correct answer Is dis-played. Each lesson ends with atest that is administered andscored by the computer. The resultsare then entered into the student'sprogress chart. More comprehen-sive examinations are given at theend of Lesson 5 and at the end ofthe course.

Suitability: This Is the kind of edu-cational programming that per-sonal computing needs more of.The student (my teenage son)learned much more quickly than Icould have taught him, and at hisown pace. However, this courseisn't just for youngsters but for any-one who wants to be able to pro-gram effectively using the BASIClanguage. In a household wherethere isn't anyone to do the teach-ing, this course would be espe-cially useful. I'd like to see a similarcourse for assembly-languageprogramming.

Other software available fromthe same vendor: IQ Builders (fourdifferent kinds). Memory Builderand Story Builder.

Reprinted with permission:

80 Microcomputing, February 1980

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BYTE May 1980 199

f START J

LAST SOUND = NULL,SOUNDEX CODE " FIRSTLETTER OF NAME

YES

1 = 2

SELECTCHARACTER

YES

PAD TO RIGHTWITH ZEROES

CONVERT TO POSITIONN ALPHABET

1=1+1

YES

YES

-*!l

ADD SOUNDEXGROUP TO CODE

SAVE LAST SOUND

TRUNCATE TO 4CHARACTERS

( RETURN J

Figure 1: Flowchart of the Soundex algorithm subroutine.

(before step 1), omit all but thefirst.4. Convert the name to the formletter, digit, digit, digit by add-ing trailing zeroes (if there areless than three digits), or by

dropping rightmost digits, ifthere are more than three.

BASIC Program

Listing 1 shows the Soundex codegenerating subprogram that con-

InputN$ — Name to be coded

OutputS$

— Soundex code of N$ (form:letter,digit,digit,digit)

Temporary

I —

E$

E

L$

Character position in N$under considerationIth Character in N$Alphabetic sequence of E$Last sound during evalua-tion

Table 3: Variables used in theSoundex program.

structs the encoded form from a lastname. It was written and tested on aCommodore PET 2001 computer, butit should work on any computerusing Microsoft BASIC. It shouldwork on other BASICs which haveLEFTS, RIGHTS, and MID$ func-tions, and use " + " for string con-catenation.

Figure 1 shows the flowchartdescribing the program's operation.Line numbers on the flowchart cor-respond to the BASIC line numbers inlisting 1. The program is separated in-to two parts: the Soundex routine,starting at line 2000, and a test driverstarting at line 100. The driver is usedto ask for a name, invoke theSoundex generator, then print theresults. It will be replaced by yourprogram logic for filing and retriev-ing. The Soundex generator in line2000 accepts as input the variable N$,representing the last name to be con-verted. It returns S$, the Soundexcode for N$.

The only tricky part of the pro-gram is contained between lines 2080and 2110. Instead of testing eachletter individually, as shown in theoriginal technique above, the pro-gram converts the letter to a numberfrom 1 to 26, representing its positionin the alphabet. It then uses thisnumber to index a character string,containing the group codes for eachletter. The comment below the indexline at line 2110 documents thistechnique, and provides a reference incase the codes need to be changed.

The Soundex subroutine may be in-corporated into programs that re-quire the computer to understanduser input. The addition of a Soundexroutine can increase the usefulness ofa computer. ■

200 May 1980 © BYTE Publications lnc

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BYTE May 1980 201

The Club Computer Network

Joe Kasser

11532 Stewart Ln

Silver Spring MD 20904

Does a club need a computer net-work? What are its uses? What arethe advantages of having such a net-work?

This article attempts to answerthese questions and provide ideas onthe techniques used in implementingthe network.

Basic Communications Needs

An important aspect of any hobbyis communication. The sharing ofinformation and experiences can adda great deal of enjoyment and savemuch time. If the techniques used tosolve some problem are made avail-able by the solvers to others, therecipients of the solution can advancethe state of the art. This is done bybuilding upon the foundationsdeveloped by the original solvers,rather than by rebuilding the samefoundations.

In the computer field, communica-tions fall into two similar but distinctcategories: the exchange of personalmessages and the exchange of com-puter data (programs or data bases).

Personal messages may containany plain language text. Computerdata may contain programs, databases, and instructions for processingfiles.

About the Author

Joe Kasser is vice-president of theChesapeake Microcomputer Club, director ofinformation and publicity of the RadioAmateur Satellite Corp (AMSAT), and editorof ORBIT. He has worked with microcom-puters professionally since 1975, and has builtan 8080-based, S-100 computer system whichserved as the prototype for the club's construc-tion project. He has contributed other articlesto BYTE, including "AMSAT 8080 StandardDebug Monitor" (September 1976, page 108,with Richard C Allen), "The Sky's the Limit"(November 1978, page 48) and "TheAMSAT-COLEM-80" (September 1979, page182).

Computer data comes in manyforms. In the personal computer area,data may be on paper tape, cassettetape, or floppy disk. If it is oncassette, it may be in a digital satura-tion format or some modulated audioformat. It may also be recorded atone of several data rates.

If data is on a floppy disk, the diskmay be soft-sectored or hard-sectored. Data may be on 5- or 8-inchdisks, which may be single or doubledensity, single or double sided. Thedisk format may be compatible to adisk operating system such as CP/Mor North Star, or it may not.

Most computer users do not havethe means for reading or writing all ofthe different types of off-line storagemedia. Thus, two users who wish toshare software may have what isknown as a "media incompatibilityproblem."

A typical example occurs in theChesapeake Microcomputer Club(CMC). Two members own 8080 orZ80-based systems, each running theDigital Research CP/M diskoperating system. One member,however, uses 8-inch soft-sectoreddisks, while the other uses a NorthStar system (5-inch hard-sectoreddisks). They have no compatiblemedium such as tape. How then arethey to share computer files?

The club is spread out over a widegeographic area. Several of theofficers require access to the clubroster or membership list. Currentlythe list is kept by one officer who hasto update it, see that labels areprinted for mailings, and sendphysical copies of the list to the otherofficers. Since officers may live 30 to50 miles apart, the telephone andpostal services are the only practicalmethod for information exchange.There must be a better way.

The club has a need for dissemi-nating information. Reports concern-ing main meetings, chapter meetings,group purchases, surplus informa-tion, and special interest groups haveto be made available to the member-ship. Currently the information ispassed out at meetings and throughthe mails by a monthly newsletter. Isthere a better way?

Many of the members possess theirown computer systems. The degree ofsophistication ranges from a simpleKIM-1 to a system with dual diskdrive, large amounts of memory, andline printers. A number of membershave become involved with the clubcomputer project and the group-purchase plan for equipment. Eachone of these systems is in a differentstage of development. Many peopleare finding that their system cannotperform the tasks that they wish it toperform, because several system com-ponents (such as extra memory ordisk storage capability) are lackingfor one reason or another. Perhapsthe capital outlay involved is notavailable, or they are waiting fordeliveries to take place.

When contemplating the purchaseof additional hardware and software,decisions involving hundreds ofdollars must be made, sometimeswith little factual information. Atclub meetings members can discusstheir requirements and experiences,but that just results in acquisition ofinformation about how a particularitem of computerware works in some-one else's environment and how itmeets his requirements.

It would be nice to be able to gettogether with a friend and gainhands-on experience of the way that acomputer system component per-forms in one's own environmentbefore purchasing it. Visiting friends

202 May 1980 © BYTE Publications he

—□

WASHINGTONDC

—— D

= TELEPHONE LINK

Q = COMPUTER —

X = PHONE USER " RADIO LINK

□ = RADIO USER (HAM)

0 ■ PHONE/RADIO USER (HAM)

Figure 1: Diagram of sample telephone and radio-data transmission links in a typicalclub computer network. Several computers form nodes in the network. Solid lines in-dicate telephone links; dotted lines indicate links through a 2-meter band amateur radiorepeater system (at the same location as one of the computers). Communities identifiedare located in northern Virginia and in Maryland (except for Washington DC).

and using their systems can providethis facility, but it is inconvenient,especially when a long session isplanned or the traveling distance isgreat. There must be a better way.

Basic Network

There ts a better way. It is called aclub computer network. All clubmembers can have access to it. It maybe centralized or distributed, but it

will provide a service to the clubmembers. Access may be via thetelephone line or via amateur radio-teletypewriter (RTTY) circuits. Eachaccess method has its own advantagesand disadvantages.

An example of such a network isshown in figure 1, It incorporatesboth radio and telephone links. It alsoallows for a number of computers inthe system. It is spread out over a

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May 19B0 © BYTE Publications lnc 203

Jack McAlister had $12,000worth of power tools.

Here's why he sold them.

"My shop was equipped with commercial tools in which I hadan investment of $ 12,000 or more. I sold all my machines at anice profit, and purchased one Mark V ... I can do anything Iwas doing on all the machines, this gives me a lot more roomand I have several thousand in the bank. What more could Iask for?" — Jack McAlister, Tucker, Georgia

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relatively wide geographic area. Onecomputer may be accessed either viaa 2-meter FM radio-teletypewriterrepeater (operated by the AmateurRadio Development Association,AMRAD, using the frequencies147.81 and 147.21 MHz), or via thetelephone line. The other computersare operated on behalf of theChesapeake Microcomputer Club Incby various members. Note that thisarea-wide operation is necessitated bythe geographic dispersal of themembership of the two clubs.

The central computers are locatedso that at least one computer is withinlocal telephone-dialing range of eachclub member. Several members maybe within local dialing range of morethan one. If one machine in the net-work is down, or in use at any par-ticular time, these members can try toaccess another computer.

The radio link can be used by vir-tually any amateur radio teleprinterstation in the area that is equipped for2-meter FM operation. Of course,any member of the club can accessany computer by making a long-distance telephone call.

Data is collected in each computerfor remote retrieval at a later time. Ifthe data in one machine is addressedto a user outside the local telephonearea, the data is automatically sent tothe computer in the distant area in thelate evening, when long-distancetelephone rates are lowest. This inter-computer transfer takes place onceper night per machine in a predeter-mined sequence to transfer the max-imum number of messages with theminimum number of calls.

Link Types

Consider first the characteristics ofthe radio links. Many amateur radiooperators already use noncomputer-ized automatic-starting radio-teletypewriter equipment for receiv-ing message traffic. A computer net-work for message handling is a logicalsuccessor to these existing autostartnetworks.

The existing noncomputerized net-work works as follows. All stationsmonitor the same frequency.Messages are sent blind; when amessage is originated into the net-work, the sender does not know forcertain if the destination station is

204 May 1980 © BYTE Publications Inc

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Computer Data Systems. Inc 25 West Woodbine Youngstown, OH 44505 (216) 747 5539

All Type Business Systems 57 Verdi Street Farmingdale. NY 11735 (516)249 4650

Microprocessor Applications Maskells Hill Road Selby. Victoria, Australia 3159 (03)7545108

Realistic Computing ot Georgia 101 Mc Cartan Street Augusta, Ga 30902 (404)7220831

Computerease 403 Milllown Road Wilmington, DE 19808 (302)995 6546

DolsonS Wilson Consulting P.O. Box 12152 Lexington. Ky 40581 (606)2339958

Forbes S Associates P 0. Box 455 Marlton, rt| 08053 (609)435 0404

Freeman Electronics 708 Norm 7tli Street West Monroe. La 71291 (318)3882312

Diversilied Data Systems 9811 Mallard Drive Laurel. MD 20811 [301)776 1200

Great Neck Computer Co 89 31 161st Street Jamaica. NY 11432 (212)2918880

Nova Group. Inc 2864 Hartland FallsChurch. VA22043 (703)6985116

Computer Center 125 Pillow Street Butler PA 16001 (412)2870754

Computer Center 31 East 31st Street New York. NY 10016 (212)8898130

Texas Microcomputers 120 North lOtn Street Mc Allen. TX 78501 (512)6878744

Computer Sales Co 63 Gentry Court Box 3351 Annapolis. MD 21403 (3011 267 6600

Inlegrated Business Systems 7009 Prospect NE Albuouerque NM87110 (505)8849705

Business Computer Systems. Inc 1401 Walnut River Canton MI48I87 1313)9813180

Custom BusinessCompulers 4565 W 77th Street Suile 136 Minneapolis MN 55435 (612|831 1580

DeWalt Computer Sales ■ POB 253 • llghtstreet, PA 17839 • (717) 784-4496

Modulo-2 - 709 Supreme House. Penang Road, Singapore 0923 - Phone: 39843, 30539

Circle 122 on inquiry card.

BYTE May 1980 205

monitoring the frequency, unless2-way contact is first established. Inthe evening, or during weekends, thismay not pose much of a problem,because the probability of someonebeing at home is great. However, dur-ing the working day, that probabilitydecreases. Thus, if contact cannot beestablished directly, the message canstill be sent, but there is a probabilitythat the destination receiver will notbe on line, and the message will belost.

If, however, the message can bestored in a central computer by thesender, and retrieved later by the

receiver, the probability of successfultransmission of the message fromsender to receiver is almost certain.The addition of a computer thereforebecomes an asset to the network.

If several stations in the networkhave computers capable of answeringback to the sender, the utilization ofthe computer may be reduced. Asender can put out a direct call. If ananswer is not received (indicating thatthe destination is not on line ormonitoring at the time), the messagecan either be transmitted to the com-puter for storage, or held andtransmission attempted again at a

64KB RAM MEMORIES

LSI-11 - $750.00 • SBC 80/10 - $750.00S-100 - $750.00 • 6800 - $750.00 • 6800-2 - $995.00

niiTiiT]!<Ifgifilft

liiiiiiiiHMUU'tllM-.

CI-6800-2 64K x 9

CI-S100 64Kx8

iHiii r

■■•«■■«■ gL••■■■•■■ [£»

""IHiii

CI-1103 32Kx16

CI-6800 64K x 8

CI-8080 64Kx8

CI-6800-2 — 16KB to 64KB. Plugsdirectly into Motorola's EXORciser I orII. Hidden refresh up to 1.5 Mhz. Cyclestealing at 2 Mhz. Addressable in 4Kincrements with respect to VXA orVUA. Optional on Board Parity. 64K x9$995.00.

CI-S100 — 16KB to 64KB. Transparenthidden refresh. No wait states at 4 Mhz.Compatible with Alpha Micro and allMajor 8080, 8085 and Z80 Based S100Systems. Expandable to 512 K bytesthru Bank Selecting. 64K x 8 $750.00.

CI-1103 — 16KB to 64KB on a singledual height board. On board hiddenrefresh. Plugs directly into LSI 11/2,H11 or LSI 11/23. Addressable in 2Kword increments up to 256 K Bytes. 8Kx 16 $390.00. 32K x 16 $750.00.

CI-6800 — 16KB to 64KB on a singleboard. On board hidden refresh. Plugsdirectly into EXORciser I and compati-ble with Rockwell's System 65.Addressable in 4K increments up to64K. 16K x 8 $390.00. 64K x 8 $750.00.

CI-8080 — 16KB to 64KB on a singleboard. Plugs directly into MDS 800 andSBC 80/10. Addressable in 4Kincrements up to 64K. 16 KB $390.00.64K $750.00.

Test and bumed-in. Full year warranty.

Chrislin Industries, Inc.

[ i Computer Products Division

31352 Via Colinas • Westlake Village, CA 91361 • 213-991-2254

C

later time. It is also possible for theassignment of which network com-puter will perform the store and for-ward operation to be rotated amongthe various member-station com-puters on basis of availability, as longas the network computer has adistinctive identification.

With a radio network set up in thisway, anyone equipped either withsimple radio-teleprinter equipment orwith sophisticated computer equip-ment may make use of the full net-work message storage and forward-ing capabilities. This concept ofallowing minimally equipped stationsto access the network requires thatsimple techniques be used for datatransfer. These include 5-level("Baudot") or ASCII plain languagetext, a control language that isreadable by both man and machine,with minimal error checking. Theadvantages of more sophisticatedtechniques mean that many peoplewill want to use them. That leads to ahierarchical concept of the networkutilization. This will be discussedlater.

The disadvantage of the radio net-work is that since everyone is on line,the privacy level is zero. Therefore,data that is not intended for publicknowledge cannot be passed over thenetwork. For this reason, mailing listsand other confidential club datashould not be passed over the radiolink. [Also, FCC regulations requirethat no message traffic pertaining toany business or commercial activitymay be transmitted by an amateurradio station...RSS]

Use of the telephone line for gain-ing access to the computer limits thenumber of users that can be on line atthe same time. One great advantageof the telephone line is security. Theconnection between the user and thecomputer is private. Mailing lists canbe accessed and changed remotelywithout compromising the security ofthe data, provided that only author-ized users are allowed access to thesedata files.

System Implementation

Bringing up the network for thefirst time can be simple or complex.One method is to install a computerequipped with dual floppy-diskdrives, 32 K bytes of memory, andthe phone line, and make it available24 hours per day. It is an expensivemethod, especially when the demand

206 May 1980 © BYTE Publications Inc

Circle 123 on inquiry card.

■

■

i

I

I

»

i

i

i

r**i I 1;

»1«

The 1980 Business & HomeComputer Shows.

Last year's spectacular success inBoston broadens its reach this year into theprosperous Chicago and Washington/Baltimore markets as well. The Business &Home Computer Shows are coming up again.But space is going fast. So call now if youwant to be a part of the hottest thing everin regional end-user computer expositions.

A SMASH LAST YEAR; EVEN BETTERTHIS YEAR.

A record-breaking 31,000 peopleattended the first of these shows in 1979, athree-day affair in Boston. This year'sevents are broadened to four days, and willhave even bigger promotional budgetsthan ever. In fact, the Business & Home Com-puter Shows have the largest nationaland regional advertising budget of anycomputer exhibits except NCC.

SELLING SHOWS S25 I-r=^==T-r€

WHERE PEOPLEREALLY BUY.

The Business & ^mrilBrJP|; JS

Home Computer Showsproduce solid results. Theseare eager audiences-about

70% businessmen and the rest hobbyists -primed with purchasing power in mini- andmicrocomputers, word processors, periph-erals, ana software. They come to buy. Andcash sales are permitted throughout the show.

CALL NOW! SPACE IS RUNNING LOW.

Four hundred booths and 100,000square feet of floor space for each of thethree shows may sound big, and it is. Butover half that space has already been sold,mostly to last year's participants. (Severalcompanies tried single booths last year andare back again with reservations for 12 to16 booths!) So hurry. Call Bill Mahan orJoan Donahue at (617) 524-4547 to getmore facts and assure your reservation.mmmm WASHINGTON/BALTIMORE: D.C.Zmmm Armory/Starplex, Thu., Sept. 18 thruSun., Sept. 21.CHICAGO.- McCormickPlace, Thu., Oct. 16 thru.Sun., Oct. 19.BOSTON: Hynes Audi-torium/Prudential Center,Thu., Nov. 20 thru Sun.,Nov. 23.

TM

RO. Box 678, Brookline, MA 02147

BYTE May 1980 207

Mailbox

SystemI

rr

Conversion

Personal

News

Fleamarket

T

— Help—Space

Line

protocol

Send

Retrieve

Help

System

Space

Logoff

Delete

Figure 2: Hierarchy of software modes in the club computer network software. Namesof program routines are enclosed in boxes. Commands available with each program arelisted below.

Send

Send

Send

Retrieve

Subject

Subject

Help

Retrieve

Retrieve

Space

Help

Help

Logoff

Space

Space

Delete

Logoff

Logoff

A Message to our Subscribers

From time to time we make theBYTE subscriber list availableto other companies who wishto send our subscribers promo-tional material about their pro-ducts. We take great care toscreen these companies,choosing only those who arereputable, and whose products,services, or information we feelwould be of interest to you.Direct mail is an efficientmedium for presenting thelatest personal computer goodsand services to our subscribers.

Many BYTE subscribers ap-preciate this controlled use ofour mailing list, and look for-ward to finding information of

interest to them in the mail.Used are our subscribers'names and addresses only (noother information we may haveis ever given).

While we believe the distribu-tion of this information is ofbenefit to our subscribers, wefirmly respect the wishes ofany subscriber who does notwant to receive such promo-tional literature. Should youwish to restrict the use of yourname, simply send your re-quest to BYTE Publications Inc,Attn: Circulation Department,70 Main St, Peterborough NH03458. Thank you.

JiJIIf 111 If lllillllltirilltlllllllllllillllllf llllIlltltlllJItlllMIIIIIIIIIIlltllllillflllllMEllllIIIII tlllllllllllllllllllllllllllllfljl

A Message from North Star

Computers Inc. j

i Due to a miscommunication between our advertising agency and =

£ BYTE Magazine, an advertisement for North Star Computer new Ap- 5

B plications Software ran in April instead of May. This ad was not intend- =

= ed to appear until all North Star dealers had been informed of our new 1

| software products and were prepared to handle customer inquiries.

We regret any inconveniences and embarrassment this has caused =§ North Star dealers and customers, and we are grateful to BYTE for £S allowing us to clarify this situation. The new Application Software =E packages will be available through North Star dealers in early May.

H Sincerely =1 Charles A. Grant

= President =

E North Star Computers Inc. S

fiT iiiliiiiJllititMiiiiifiiiiiiiliiiiiilililiiiilllii mil iiiiiiittlfiillfliJif iniiillfiiiiii mil Jiiiliiiiiiiiiini ITi

for such a service has not yet beendemonstrated in the club.

A second method is to bring theservice on line gradually, using equip-ment belonging to club members, andthen put together a club system asclub finances allow. This method hasthe advantage that the cost can bespread out over a period of time, butdoes have a disadvantage becausethere will be many intervals duringthe early stages of the network im-plementation when the system is notavailable.

The network can be started by oneor more club members making theirpersonal systems available. On theradio link, there will be no noticeabledifference with the different com-puters, since they should all answerto the same call sign, and the userneed not know which machine is stor-ing his traffic. In practice each com-puter will also transmit its own sta-tion call sign as required by law.

Telephone access is a little moredifficult, because a list of numbersmust be made available to the net-work members, and a rule must beestablished for dialing the computer.An example of such a rule is that ifthe computer does not answer by thesecond ring, dial another number.

When the system is first put intouse, it will be lightly loaded. It canthus be used for secondary purposesapart from the message storage ormedia transfer applications. Clubmembers will have a chance to use thesophisticated system and to play withit. The availability of any single com-puter during the early stages may beintermittent: since it is the personalsystem of a club member, it will beavailable for club use only when theowner is not using it. This unreliableaccessibility will encourage membersto upgrade their systems as fast aspossible for their noncommunicationuses. However, the system as a wholewill have a greater reliability, sincethere is a good probability that atleast one computer will be availablewhen one is required.

Using the Telephone Link

The typical telephone communica-tion system operates at a data rate ofeither 110 or 300 bits per second(bps), allowing the use of simple Bell103-compatible modems. In order toset the data rate for a transmission,each user must transmit a carriage

208 May 1980 © BYTE Publications Inc

k£5

An Extraordinary Offer to introduce you to the benefits of Membership in

ELECTRONICS BOOK CLUB

invites you to take Cthis 1,442-page ^Computer Libraryfor only

YouGet ALL

FIVE 0 These

Huge Books

For Only

$1.99

Microprocessor Cookbook

A chip-by-chip comparison of the most popular modernmicroprocessors—including programming, architecture, ad-dressing, instruction sets, and applications! You get completedata on what makes up the structure of a microprocessor chipand a microcomputer, how to give instructions, the overallorganization of a computer system, and more. Then you get achip-by-chip profile of modern microprocessors—with thoroughdiscussions of applications, architecture, functions, etc. In-cluded are the Intel 8080, Motorola 6800, Fairchild's F8 family,Zilog Z80, Tl's TMS 9900, National Semi SC/MP, Intel's 8021,and many more. 266 pps., 124 illus. List $9.95

The BASIC Cookbook

A complete dictionary of all BASIC statements, commands, andfunctions—with programming examples and flowcharts.Thoroughly defines the BASIC vocabulary in alphabetical order,illustrates the definitions with sample programs, and furtherclarifies the programs with matching flowcharts . . . plusexplaining BASIC system commands. You'll learn how to profes-sionally manipulate and use each BASIC term in a workableprogram. Also defines programming terms that apply to APL,ALGOL, COBOL, FORTRAN, RPG, PL1, etc. 140 pps., 49 illus. List$7.95

57 Practical Programs & Games in BASIC

57 of the hardest working, most enjoyable BASIC programsyou've ever seen . . . everything from space war games toblackjack, from craps to I Ching, from arithmetic progression tostatistical permutations to one-arm bandits! It's an easy-to-usemanual that gives you 57 different simplified BASIC pro-grams ... all ready to run! You can program your minibrain forall kinds of fun and games, or for solving many different types ofproblems. 210 pps., 64 illus. List $10.95

Complete Microcomputer Systems Hdbook.

A complete guide to microcomputers—how they operate, how touse them, how to program them, and how to troubleshoot, test,and repair them ... plus the very latest on modern applicationslike magnetic bubble memories, computers in networks, compu-ter decision making, simulation and forecasting, teachingmachines to learn, robot control, speech synthesizers, digitalmusic, mobile computers, etc. There's extensive coverage ofcomputer problems and how to diagnose and repair them, pluslots of hard debugging data. You'll learn how to find and fix alltypes of mechanical and electronic troubles—plus how to usetest signals and closed loop signals, how to replace chips, how toalign disc drives, etc. 322 pps., 147 illus. List $15.95

The Giant Handbook of Computer Projects

Thi s MAMMOTH 504-page step-by-step guide to building moderncomputers and accessories—CPUs, memories, I/O hardware,etc.—is a HUGE collection of ready-to-use construction info. It'sa builder's dream, with projects, complete schematics, partslists, and step-by-step construction instructions that let youbuild your own systems. Also contains a thorough discussion ofmicroprocessors, with comparisons of several units, includingthe Kim-1, the Z-80, and the 8080, etc.... plus data on memoryboards, RAM checkout, PROM programmers, memory chips, inex-pensive input/output devices, paper tape systems, interfacingwith clock chips, and more. 504 pps., 217 illus. List $15.95

57 PRACTICAL

PROGRAMS & GAMES

IN BASIC

Ithe complete

I MICROCOMPUTERSYSTEMS HANDBOOK,

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Let us send you this 5-volume, 1,442 p.Computer Library us part of an unusualof a Trial Membership in Electronics Book Club.Here are quality hardbound volumes, eachespecially designed to help you increase yourknow-how, earning power, and enjoyment of elec-tronics and computers. Whatever your interestin electronics/computers, you'll find ElectronicsBook Club offers practical, quality books that youcan put to immediate use and benefit.

This extraordinary offer is intended to proveto you, through your own experience, that thesevery real advantages can be yours. . . that it ispossible to keep up with the literature publishedin your areas of interest, and to save substantiallywhile so doing. As part of your Trial Membership,you need purchase as few as four books during

• Only $1.99 forALL FIVE!

Regular ListPrice $60.75

Top-QualityHardbinding

Contains thevery latestinfo oncomputers!

Over 600illustrations

Contains over500,000 words

1,442 data-packed pages

the coming 12 months. You would probably buy atleast this many anyway, without the substantialsavings offered through Club Membership.

To start your Membership on these attrac-tive terms, simply fill out and mail the coupon to-day. You will receive the 5-volume ComputerLibrary for 10-day inspection. YOU NEED SENDNO MONEY. If you're not delighted, return thebooks within 10 days and your Trial Membershipwill be cancelled without cost or obligation.

ELECTRONICS BOOK CLUB. Blue Ridge Summit, Pa. 17214

Facts About Club Membership

• The 5 introductory boohs carry a publisher's retail price of$60.75. They are yours for only $1 99 for all 5 (plus postage/handling) with your Trial Membership.

• You will receive the Club News, describing the current Selec-tion, Alternates, and other books, every 4 weeks (13x a year)

• If you want the Selection, do nothing, it will be sent to youautomatically If you do not wish to receive the Selection, or if youwant to order one of the many Alternates offered, you simply giveinstructions on the reply form (and in the envelope) provided,and return it to us by the date specified This date allows you alleast 10 days in which to return the form If. because of late maildelivery, you do not have 10 days to make a decision and soreceive an unwanted Selection, you may return it at Club ex-pense

• To complete your Trial Membership, you need buy only fouradditional monthly Selections or Alternates during the next 12months You may cancel your Membership any time after youpurchase these four books

• All books —including the Introductory Offei—are fully returnable after 10 days if you re nol completely satisfied

• All books are ottered at low Member puces, plus a smallpostage and handling charge

• Continuing Bonus: If you continue after this Trial Membership,you will earn a Dividend Certificate for every book you purchase.Three Certificates.plus payment of the nominal sum of $1.99 willentitle you to a valuable Book Dividend of your choice which youmay choose from a list provided Members.

ELECTRONICS BOOK CLUB

Blue Ridge Summit, Pa. 17214

Please open my Trial Membership in ELEC-TRONICS BOOK CLUB and send my 5-volumeComputer Library, invoicing me for only $1.99plus shipping. If not delighted, I may return thebooks within 10 days and owe nothing, andhave my Trial Membership cancelled. I agreeto purchase at least four additonal books dur-ing the next 12 months after which I maycancel my membership at any time.

Name_

Phone_

Address_City

State.

-Zip-

(Valid lor new Members only. Foreign and Canada add 15'».]BY-580

Circle 126 on inquiry card.

BYTE May 1980 209

CMC NETWORK. ENTER LOGON:-G3ZCZ

G3ZCZ LOGON IN PROGRESS AT 1115 ON 6 NOV 1978

4 MESSAGES

READY MAILBOX

MAILBOX READY HELP

CHOOSE BETWEEN 'SEND, RETRIEVE, HELP, SPACE, LOGOFF'

MAILBOX READY SPACE

DISC SPACE = 25K

MAILBOX READY SEND

DESTINATION? WB4APR

INPUT: — BOB, WE HAVE TO DISCUSS THE RADIO PROTOCOL. CALL ME WHEN YOU HAVE A MOMENT, BETWEEN 9 AND 11

PM ANY NIGHT EXCEPT FRIDAY. [control-Z]MESSAGE ACCEPTEDMAILBOX READY RETREIVERETREIVE IS NOT VALIDMAILBOX READY RETRIEVE

MESSAGE1234

SOURCEWB4APRCMC 105TERRY FOXG8BTB

DATED1 NOV 19783 NOV 19785 NOV 19785 NOV 1978

MAILBOX READY RETRIEVE 2

MESSAGE READS:MAILBOX READY

BRING THE DOCUMENTATION ON THE GLOOP BOX TO THE MEETING. FRED.

Figure 3: Sample interaction between the author (G3ZCZ) and the Chesapeake Microcomputer Club-Amateur Radio DevelopmentAssociation (CMC-AMRAD) computer system. Characters sent by the system are shown in regular type; those typed by the user areshown in boldface type. Note that when the "RETREIVE" command (a misspelling) is entered, an error message is generated by thesystem.

return character so that the computercan set up the correct data rate. Oncethe data rate is established, the com-puter sends out a sign-on message andasks the user to log in with an iden-tification code. This identificationcan be a membership number, anamateur radio call sign, or some ar-bitrary name. It is limited to a lengthof eight characters. The computerwill then indicate the presence orabsence of any personal messagesaddressed to the user that has justlogged in.

The software in each computer isidentical in behavior and is organizedin a structured top-down approach asshown in figure 2. The user has achoice of programs as shown that

perform the various functions.Various commands are associatedwith each program as listed. Considereach program and mode in turn.

The mailbox program is designedto enable club members to send shortmessages (up to 256 characters) toeach other. The messages are in plainlanguage. The response to a SENDcommand is to prompt the user withDESTINATION? Upon entering theidentification code of the destination,the user is prompted to send themessage and terminate it with acontrol-Z character. Should morethan 256 characters be entered, theentire message will be rejected. Thisdiscourages long messages.

The response to the RETRIEVE

command is to list the sender iden-tification of each message in thesystem awaiting the user.

A sample user session is shown infigure 3. The computer output isshown in regular type, the user inputin boldface type.

The other messages may beretrieved in turn. The RETRIEVEcommand has the followingcharacteristics: If followed by a car-riage return, it lists all messages. Iffollowed by a 0, it lists all messages.If followed by a number, it lists thecorresponding message.

Identification numbers are assignedto the messages only to allow the userto retrieve them. The numbers arereassigned as messages are deleted.

UCSD Pascal* for TRS-SO^ Model II

The Standard Package: Operating System □ Compiler □ Screen Editor n Filer n Library D Z-80 Assembler□ Patch Utility Program □ 280 page User Manual □ Jensen & Wirth Pascal Reference Manual □ Bowles' BeginnersGuide To UCSD Pascal □ tutorial disk.

Plus:

Optional Utility Programs:

• File conversion—

CP/M* to Pascal $50.00

TRSDOS to Pascal $50.00

•Z-80 Disassembler/Dump Program $50.00

PCD SYSTEMS 323 Keuka St. • Penn Yan • New York 14527 • 315-536-3734

♦Trademark of the Regents of the University of California tTraclemark of Tandy Corp. (Trademark of Digital Research Corp.

• Single or double density diskettes in one or morestandard formats.

• Disk Formatting program. $350

• Configuration program for serial I/O. Complete

210 May 1980 © BYTE Publications Inc

Circle 127 on inquiry card.

No matter what type of personal computeryou have, or are thinking of buying, EatonLRC's new 7000+ dot-matrix impact printer canbe interfaced with plug-in simplicity and beprinting in just a matter of seconds.

The 7000+ features uni-directional printingwith a line speed of 1.25 lines per second. It ac-cepts any single or two-ply paper roll from3/4-inch to 3-7/8 inches wide and prints a 3-1/3inch line. Capacity is adjustable and can be 40columns at 12 characters to the inch using thesingle width font; or 20 columns at 6 charactersto the inch using the double-width font. The7000+ accepts the full ASCII character set (up-per and lower case). An available option allowsthe unit to print 64 columns at the single widthsetting, and 32 columns using a double widthfont, selectable under software control.The new 7000 +comes equ^ped with Eaton LRC's newest printhead with a minimum life of100-million characters. This new, long-life head has been carefully designed to print continuouslywithout overheating.

7000+ (40 & 20 columns) List $389 $369 7000+ (64, 32, 40 & 20 col.) List $405 $389

APPLE cable $20 TRS-80 cable $20

DEALER INQUIRIES INVITED

TRS-80*COMPUTERS:

Level II, 4K (list $619) $559

Level II, 16K, no keypad $669

Level II, 16K, w/keypad (list $849) $749

EXPANSION INTERFACES:

Exp. Int., no RAM (list $299) $269

Exp. Int., 16K RAM, (NEC) (list $448) $369

Exp. Int., 32K RAM, (NEC) (list $597) $459

DISK DRIVES:

Percom, TFD-100,40-track (list $399) $389

Percom, Dual TFD-100's (list $795) $775

Percom, TFD-200, 77-track (list $675) $650

Percom, Dual TFD-200's (list $1350) $1300

RS Mini-Disk #0 (list $499) $449

RS Mini-Disk #1-2-3(list $499) $439

DISK DRIVE ACCESSORIES:

2-drive cable for TRS-80 (list $29.95) $29

4-drive cable for TRS-80 (list $39.95) $39

Percom Data Separator $29.95

Extender Card (list $15.95) $15

PRINTERS:

Centronics 730 (list $795)

$719

TO ORDERTOLL-FREE

1-800-258-1790

Centronics 737 (list $995) $895

Centronics 753-2 (list $3196) $2695

Centronics 779-2 (list $1559) $ 995

RS Quick Printer II ($219) $197

RS Line Printer III (list $1960) $1813

NEC 5530 Spinwriter (list $2995) $2595

LRC 7000+ (list $389) $369

LRD 7000 + (list $405) $389

PRINTER CABLES:

QPII to Exp. Int. cable ($19.95) $19

LRC to TRS-80 cable (list $20)

730 to TRS-80 cable $29

779 or 753 to TRS-80 cable $35

NEC 5530 to TRS-80 cable $35

PERIPHERALS:

Novation CAT Modem ($189.95) $179

UDS 103-LP $195

RS-232-C Interface Board (list $99) $89

TRS-232 Printer Interface $49.95

Data Dubber $49.95

16K Memory Kit, Keyboard $99

16K Memory Upgrade Kit, E.I $95

Percom Electric Crayon, w/cable $279.95

Busy Box $109.95

BSR X-10, Starter Kit $124.95

Comm-80 Interface $179.95

6 SOUTH ST.,MILFORD, NH 03055

I

(In N.H. call 673-5144)

We buy & sell,used TRS-80s. Call(603)673-5144for details!

"TRS-80 Is a trademark of Radio Shack and Tandy Corp. "Apple Is a trademark of the Apple Computer Co.

Circle 128 on inquiry card.

BYTE May 1980 211

Deletion of messages is allowed bythe system under restricted condi-tions. Only the system manager, thesender, or the retriever can deletemessages. Each user is assigned apassword that must be entered priorto a DELETE command. This allowssome degree of security. Messageswill be deleted by the system managerperiodically, depending on thestorage requirements of the system.

In the news and fleamarket modes,updates are handled by a single clubmember designated for that duty. Allmessages for input to the system arerouted to this person for scanningbefore being placed on the system.This is to keep the system from beingcluttered up with undesirablemessages. Updates of these messagestake place as time permits, with amaximum delay time of one week.

The conversion program is de-signed for exchange of data betweendifferent media. One club memberdesiring to receive a data file fromanother will arrange for the secondmember to put the file into the systemfor retrieval within hours. The ex-pected life of a file in the conversionmode is about 24 hours. Conversionuses a different protocol than themailbox mode. Since long files are be-ing exchanged, the data flow has tobe stopped from time to time to allowdisk read and write operations. Afull-duplex mode is used.

The maximum message length of256 characters applies in all modesexcept conversion. Messages withmore than 256 characters are rejectedin their entirety. This encouragesbrevity. A rejection message isprinted by the computer to the senderin the case of a message rejection. Auser who has to retype messages willsoon get the idea.

Several existing network systemscarry a large number of undesirablemessages. We hope to minimize themin the CMC-AMRAD network. Anyuser trying to enter unwantedmessages may have them rejected bythe system manager.

Data Complexity Levels

Data may be transmitted over alink at one of several levels of com-plexity of internal organization. Thebasic level (level 0) is plain ASCII-encoded text in half-duplex mode.Level 1 is a simple ASCII-based, full-duplex mode developed by TimPugh. Level 2 is an emulation of thePCNET (personal computer network)protocol. Level 0 is used by anyone intalking to the computer during execu-tion of any user program. Level 1may be used in the conversion mode,while Level 2 is used for intercom-puter data exchange. Any properlyequipped user can request any levelwhen he logs onto the system.

Any club member having ananswer-mode modem can run thebasic network system software on hisor her machine. An extension can bemade to the system to allow access tothe disk operating system so thatother club members can play withthe other software available on themachine.

Radio Restrictions

Mailbox and news are the onlycategories of data exchange availablevia radio links. Conversion-modedata may contain binary or otherunusually coded files, and fleamarketmay contain advertisements; radiotransmission of both of these classesof messages is forbidden by law.

The procedure for logging onto thesystem is different from the one used

over the telephone. Half-duplex modeis employed when using a single-bandrepeater, such as the 147.81/147.21MHz AMRAD machine. If the inputsand outputs were on differentamateur frequency bands, full-duplexoperation would be easily achievable.In order to avoid the requirements forduplex exchanges and to reduce theamount of information exchanged,the modified Q code is employed.See my article "The Sky's the Limit:Use Ham Radio Bands for Intercom-puter Communication" (November1978 BYTE, page 48), for a morecomplete discussion of the use ofthese Q codes.

[The Q code is a system of 3-letterabbreviations that all begin with theletter Q. Various Q codes are usedduring Morse-code radio transmis-sions to speed up message exchange.An adapted set of Q codes is used forcomputer network communication...RSS/

Any amateur can log into the net-work and receive a reply from anyon-line computer that has a messagefor him or her. Thus, users withoutcomputers can store their messages inthe network computer; those withcomputers can leave messages ontheir own machine for later remoteretrieval. Possible contention inter-ference (from more than one machinesimultaneously trying to com-municate over the network) can beovercome initially by employing adifferent time-delay responsecharacteristic for each computer inthe network (both user and systemcomputers).

The radio link can also be used forlong-distance links between the clubnetwork and other club networks.Again, see "The Sky's the Limit" for amore complete discussion. ■

AIM 65

AIM 65 is fully assembled, tested and warranted. With the addition of a low cost, readily available powersupply, it's ready to start working for you. It has an addressing capability up to 65K bytes, and comeswith a user-dedicated 1K or 4K RAM.

• Thermal Printer

• Full-Size Alphanumeric Keyboard

• True Alphanumeric Display

• Proven R6500 Microcomputer System Devices

• Built-in Expansion Capability

• TTY and Audio Cassette Interfaces

• ROM Resident Advanced Interactive Monitor

• Advanced Interactive Monitor Commands

PRICE: $37^60

(1K RAM)

$369.00

Plus $4.00 UPS (shipped in U.S. must give street address), $10 parcel post to APO's, FPO's, Alaska,Hawaii,Canada, $25 air mail to all other countries

We manufacture a complete line of high quality expansion boards. Use reader service card to be addedto our mailing list, or U.S. residents send $1.00 (International send $3.00 U.S.) for airmail delivery of our

complete catalog.

Circle 193 on inquiry card.

ENTERPRISES

INCORPORATED

2967 W. Fairmount Avenue • Phoenix, AZ 85017 • (602) 265-7564

212 May 1980 © BYTE Publications tec

Circle 129 on inquiry card.

INTRODUCING A GREAT WARGAMEFOR TWO GREAT HOME COMPUTERS.

COMPUTER BISMARCKFOR YOURAPPLE II OR TRS-80.

Historical wargaming may be the only intellectualhobby which creates more intensely devoted fanaticsthan home computing. When two wargamers spendan evening relighting a famous battle, they'll spendseveral hours happily setting up the gameboard,firepower charts, unit strength tables and so forth... allbefore the first shot can be fired! There are such paper& pencil simulations of every famous battle from Shilohto El Alamein. If you've ever tried one, you alreadyknow the excitement and challenge of trying to be abetter general than Rommel.

Home Computer

Now there's a true historical wargame for yourhome computer. Computer Bismarck accurately simu-lates the epic battle between the awesome Germanbattleship and the British Home Fleet. Best of all, thecomputer program eliminates the drudgery of paper &pencil wargames — remembering all the rules anddetails while keeping track of the battle on a NorthAtlantic map on your video display.

Play the Computer

It maneuvers the Bismarck and Prinz Eugen so wellthat you'll have to command the British ships brilliantlyto avoid losing your vital merchant convoys.

Ploy a Human

The two of you plot your strategies in grease pencilon an off-screen mapboard while the battle is fought onthe video screen (monochrome or multi-color depend-ing on your display capabilities). You deploy battleships,cruisers, carriers — each with unique and realisticoperating parameters. You must deal with all thevariables which challenge an actual battle com-mander: firepower and damage; shadowing ability(better in radar-equipped vessels); and visibility —which depends on weather, which varies with geog-raphy and time. If the game is interrupted, the computersaves it on a minidisc for resumption later.

More like Chess than Pong

Computer Bismarck is a test of intellect and couragerather than hand-eye coordination. If you can imagineplaying chess with pieces like a knight who must returnto the stables periodically for a fresh horse or a queenwhose radius of action can be affected by battledamage ... all on a 360 square chessboard partiallyobscured by fog ... that's Computer Bismarck!

Cassette for Your TRS-80

We've just described the cassette version of Com-puter Bismarck which is played on a 16K Level II TRS-80system. For $49.95 you get a programmed cassette, a12-page rule book, 2 mapboard charts (for plottingsecret strategies in grease pencil between moves), 2ship data charts, and a set-up instructions sheet,

Disc for your Apple

The disc version includes all of the cassette featuresplus actual submarine, destroyer, convoy, and aircraftunits that are moved by the players. Players must alsodeal with fuel restrictions on both ships and planes andwith the ever-changing weather of the North Atlantic.

If you've got an Apple II Plus (or an Apple II withApplesoft ROM Card) with 48K memory and a 514" minifloppy disc drive, you can be playing ComputerBismarck in a few days. For $59.95 you get the gameprogram disc, 2 mapboard charts, 2 ship data charts, 2system command cards, a loading instruction sheet,and a rulebook — everything you need to play one ofthe most exciting wargames ever designed!

Credit card holders call 800-648-5600 (toll free)and ask Operator 180 to charge your order to your VISAor MASTERCHARGE (Nevada only call 800-992-5710).Or send a check to Strategic Simulations, Incorporated,P.O. Box 5161, Stanford, CA 94305 (California residentsadd 6.5% sales tax).

For complete details and an inside look at Computer Bismarck,we'll mail you its rulebook. Just send us a check tor S5 along with yourname and address. Please indicate cassette or disc version rulebook.The S5 will be credited to your purchase ot Computer Bismarck.

COMPUTER BISMARCK." There's never been anything like It. ^^

Circle 130 on inquiry card.

BYTE May 1980 213

Circle 131 on inquiry card.

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The COSMACDoodler

Jeff Duntemann301 Susquehanna RdRochester NY 14618

When the COSMAC ELF micro-computer first appeared several yearsago, its designer called it a microcom-puter trainer. That meant that youhad a few hexadecimal displays and alight-emitting diode (LED) to playwith in your programs, and nothingelse. Clever people managed to makethe ELF play music or even generateMorse code without much additionalhardware.

As far as I know, the ELF is theonly microcomputer that has oftenbeen built from scratch by hobbyistswithout using a predesigned printed-circuit board. There is no better wayto learn microprocessor hardwarethan to buy a handful of parts andwire-wrap all of the connections. Inironing out your mistakes, you willbecome familiar with every processortiming signal, every kink in everysystem timing diagram, and every lit-tle architectural quirk that can growup to be a big bug in later programs.It is a rigorous education, I promiseyou, but an excellent one.

Then RCA released the CDP1861video-display-controller integratedcircuit for sale, and suddenly the ELFcould do something no comparablecomputer could do for triple theprice. With the CDP1861, the ELFdisplays a bit-map of 1024 bytes ofmemory on a video screen (in blackand white), with no hardware neededexcept the CDP1861 and several resis-tors, and with software consisting ofa 30-byte interrupt routine.

This development was not purely agift to hobbyists, of course. The

About the Author

Jeff Duntemann works for Xerox Corp. Hehas built a small robot (named Cosmo) that hecontrols with his computer, and enjoysamateur radio operation (as KB2JN). Hiswriting is not confined to technical articles; hehas had a science fiction story published inIsaac Asimov's Science Fiction Magazine.

CDP1861 formed the heart of RCA'sStudio One home video game. Insuch games cost is probably the mostimportant factor. Video-game-typegraphic displays are now easily doneon the ELF. The fourth article in theELF series ("Build the PIXIE GraphicsDisplay," Joseph A Weisbecker,Popular Electronics, July 1977, page41) outlined the hardware requiredand included a simple test program,but it was up to hobbyists to come upwith video software to make the ELFearn its keep.

The Video Doodler program pre-sents a winking cursor in the upperleft-hand corner of the screen. Byactuating toggle switches, the cursorcan be made to move horizontally,vertically, or diagonally. As itmoves, it either leaves behind a trailof white dots against the black back-ground, or it "eats" previously writ-ten white dots and lines back toblackness. Once you fill the screen,one push of the INPUT switch wipesit clean again.

Memory Requirements

The only problem is the program'ssize. Within the limits of a typical ELFone-page memory system, there is noroom left in memory after you togglein the program to do any drawing onthe screen. The only way out of thisproblem is to expand memory to atleast two 256-byte pages. If you shopwisely, you can do this for less than$9.00. Adding another page of mem-ory requires only two additional 2101static memory chips and a CD4042complementary metal-oxide semi-conductor (CMOS) latch. Figure 1details an ELF two-page memorysystem.

If you do not intend to add muchmore memory beyond two or threepages, you might consider replacing

Text continued on page 218

214 May 1980 © BYTE Publications Inc

OSBORNE/McGraw-Hill presents

Over 200,000 copies sold since"December 1975. Now completelyrevised! The most current and topicalbook on the market!

An Introduction to

Microcomputers

■

An Introduction to Microcomputers: Volume 1 —Basic Concepts

2nd Edition, by Dr. Adam Osborne

This new edition of Volume 1, published in April 1980, incorporates all of thenewest technology. Basic microprocessor concepts are discussed in terms ofmodern hardware configurations, and examples of common microcomputer ap-plications are drawn from today's most popular devices. For example, the logicinstructions and programming concepts of the new 16-bit microprocessors arediscussed in detail, and current logic distribution configurations are usedthroughout the text, illustrations and examples. Programming mnemonics conformto the newly proposed IEEE standard. This book is the first in print to use them, afeature which will be appreciated by beginners and professionals alike.Basic Concepts presents the fundamental logic framework upon which microcom-puter systems are built, so that the reader can evaluate the applicability of microcom-puters to any practical problem. Using concepts that are common to all microprocessorsystems, Volume 1 develops a detailed picture of what a microcomputer can do, how itdoes what itdoes, and how its particular capabilities can best be applied.

#34-9, $12.50

Also in the Introduction to Microcomputers series:

Volume 0 —The Beginner's Book

by Adam Osborne

m

This book introduces com-puter logic and ter-minology to the completebeginner In the field ofmicrocomputers.Numerous illustrationsand photographs combinewith clear, easy-to-followtext to provide an elemen-tary but broad-basedbackground.

#26-8 $7.95

Volume 2 —Some Real Microprocessors

by Adam Osborne et a).

This unique reference provides objective descrip-tions of virtually every microprocessor on themarket today. Lets you know what's available,how they work (or don't work), and how to usethem. Loose-leaf. Binders and yearly updates (sixissues) sold separately.

Vol. 2 book. 1978 cd. #15-2 $25.00

Vol. 2 binder #16-0 $ 5.00

Vol. 2 1978/79 updates #97 $25.00

Volume 3 —Some Real Support Devices

by Jerry Kane et al.

Same objective, in-depth coverage as Volume 2,but applied to support devices: memory, dataconverters, data communication devices, directmemory access controllers, busses, and muchmore. Loose-leaf. Binders and yearly updates (sixissues) sold separately.

Vol. 3 book. 1978 ed. #18-7 $15.00

Vol. 3 binder #19-5 $ 5.00

Vol. 3 1978/79 updates #98 $25.00

Combined update subscriptions can be purchased for both Volume 2 and 3,a total of twelve update Issues. #99 $40.oo

r

Book

Price

Quantity

Amount

NAMF

#

AnnRFSs

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CITY STATF7IP PHONF-

#*T 1 OSBORNE/McGraw-Hill

630 Bancroft Way, Dept. B4Berkeley, CA 94710 Ei'ildl(415) 548-2805 Siv2TWX 910-366-7277 1 ■ fl i 1

#

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Calif, residents add 6% sales tax. Subtotal

No tax on update subscriptions. California residents taxSHIPPING {Shipping (or large orders to be arranged)

D All foreign orders $4.00 per Item for air mall ShippingD No charge In the U.S.on update subscriptions tdtaia $0.75 Der Item 4th class In the U.S. (allow 3-4 weeksl

a $1.25 per Item UPS In the U.S. (allow 10 days)D $2.50 per Item special rush shipment by air In the UFor faster shipment or credit card, phone (415) 548-281

S.5

Circle 132 on Inquiry card.

BYTE May 1980 215

CD

CO CO CO CO 00

CD C\Jl-T-!-l-

Q. -a- oooo

>> Oi- i- ■>- *-

I— 1 CMCMOJ CM

n

E

2 OOOOO

0000 0000

U£

o S

H LU

32S

— eg £

K Is

aOOAGOOO 60 +

0000 0000

^H cm m

Figure 1: Schematic diagram of a two-page programmable-memory system that can easily be added to a COSMAC ELF microcom-puter. Pins 17 and 22 of the memory parts should not be connected together. Instead of 2101 memory devices, it is possible tosubstitute CMOS 5101, 74C920, or CDP1822CD parts. Use of complementary metal-oxide semiconductor memories enables the useof batteries to retain data in memory even when the main power supply is shut off.

216 May 1980 © BYTE Publications tac

Telecommunications Software Professionals:

OURCOMPUTERS

WANT TO

TALK

WITH

YOU

Some of the bestcomputer systems in thebusiness are looking for newways to express themselves. May-be you're the one to make this happen.

Wang is one of the top manufacturers ofcomputers and word processing systems of allsizes. We're #1 in CRT-based word processing, #2 insmall business computers. Now we're seeking to estab-lish and maintain a leading posture in telecommunicationsinvolving state-of-the-art networking and protocols.

Wang is committed to providing the resources you need to get resultsWe're moving into a brand new facility—a 12 story tower with fully modernequipment. The right kind of environment for you to achieve your best. We'redetermined to make Wang the best in telecommunications, so join us andtogether we'll start new telecommunications projects.

Last year this group grew 400%. We expect our telecommunicationsdevelopment and support staff to double in the next 12 months, and you canshape your career as you grow with us.

If you're talented in telecommunications...then let our computers know whatyou have to say.

TelecommunicationsSystems Programmers

Associate to Senior LevelProject Leaders

If you're a design oriented software developmentspecialist who is not only comfortable with on-goingtelecommunications standards such as 3270, HASP, x.25and SDLC/SNA but also capable of addressing the longrange projects of the future in protocol and network-ing development, then we may have a position for you.Systems Programmers are needed to design, develop andmaintain telecommunications systems for our total pro-duct line. Positions exist in our Development, SystemsEngineering, and Product Support areas and offer achallenge unparalleled in other organizations.These positions are new and represent ground flooropportunities for total systems responsibilities.

Telecommunications SoftwareTechnical Writers

Positions exist for qualified writers who are interestedin researching, organizing, and writing telecommuni-cations related documents. Projects include Opera-tors' Manuals, Network/Operations/CommunicationsManagers' Manuals, Technical Staff Programmers'Guides and data sheets. Two or more years technicalexperience and a Bachelor's Degree are required.It you are Interested In the above positions please sendyour resume, Including salary history to Susan Morse,Professional Recruiter, Wang Laboratories, Inc.,Dept. B-1 , One Industrial Avenue, Lowell, MA 01B51

( WANG )

Telecommunications SystemsSupport Analysts

Software verification is this group's specialty. Wemake crucial decisions regarding theeffectiveness of new developments in a hands-on environ-ment, from minis to mainframes.Working with all Wang's product lines you will beresponsible for the support activities of all Wang'sTC products and write telecommunication applicationsoftware in higher level languages. Frequentinteraction with marketing and development will berequired.

The Telecommunication Support Analyst will supportthe pre and post development and pre-installation ac-tivities as well as participate in the definition,specification and evaluation of Wang's telecommuni-cation products.

To qualify, you should have a strong data communica-tions background including experience withprotocols, modems, networks, and telecommunicationhardware and software. Prior experience with largeIBM systems 3270 networks or PJE terminals is desirable.

Telecommunications RemoteDiagnostic Engineers

Individuals with strong hardware background (BSEE orMSEE) are needed to locate potential problem areas inthe entire Wang line of telecommunication products.You will design fault isolation diagnostics andpower-up diagnostic software and real-time,remote, micro-code, environment utilizing microsthrough mainframe. You must be able to effectivelyinterface with both hardware and software develop-ment teams.

If you are interested in the above positions please sendresume Including salary history, to Thomas Bahlo,Professional Recruiter, Wang Laboratories, Inc.,Dept. B-1 , One Industrial Avenue, Lowell MA 01851.Wang offers excellent salary and benefits Includingprofit sharing, stock purchase plan, stock bonus plan,medical and dental insurance.

We are an affirmative action employe!

Making the world more productive,

+ 5V

TO PIN 17

OF ALL £*-i

CMOS r

MEMORY

. READ/WRITE

9 STANDBY

+ 5V

TO PIN 22OF ALLCMOSMEMORY

<D-

IN9I4

-w-

' TANTALUM

m

i2on

I/2W

+L 3-9V-=_ NICKEL-CADMIUMT BATTERY

Figure 2: Memory data-retention circuit for CMOS memories. Do not use this circuitwith a 2101-type memory. The nickel-cadmium battery cells charge during normaloperation, and thereafter maintain data in the memory when main power has beenturned off.

Text continued from page 214:your 2101 devices with CMOS 5101or CDP1822 memory. A small 3.9 Vbattery can allow data to be retainedin CMOS memory even when themain power is off, thus keeping youfrom facing the exasperating job oftoggle-loading 195 bytes every timeyou want to show off the Doodler.

If you can locate a 3.9 V nickel-cadmium battery, the circuit in figure2 can be built and then forgottenabout. The ni-cad will charge whilethe power is on, and keep memoryalive when power is off. If you

operate your ELF at least a few hoursper month, the battery will neverfully discharge.

Register Use

The Doodler program makes heavyuse of the COSMAC general-purposeregisters. A register-use summary isgiven in table 1 to keep everythingstraight while you are trying tounderstand the program's operation.

Where Is the Cursor?

It takes two pointers to specify a

cursor position on the screen. Thebyte pointer is the memory address ofa single byte somewhere among the256 bytes displayed on the screen.

The bit pointer is a byte stored inhalf of a general-purpose register.Only one bit of this byte ever con-tains a binary 1. This bit representsthe position of the cursor within thebyte indicated by the byte pointer.

The Doodler actually has two setsof pointers for its cursor. The per-manent pointers contain the actualposition of the cursor at any giventime. The temporary pointers aremodified during each scan of thetoggle switches.

The toggle switches are read andseparately tested by shifting bits outof the D register (COSMAC's accu-mulator). Each of the first fiveswitches controls a program function.If the first toggle switch is actuated,the temporary bit pointer is shiftedone bit to the right. If during this shiftthe bit crosses over into the next byte,the temporary byte pointer is incre-mented by one.

Actuating the second toggle switchshifts the bit pointer to the left, anddecrements the byte pointer if the bitcrosses the border into the next byteleftward. The third toggle switchadds the hexadecimal value 08 to thebyte pointer. This does not affect the

Photo 1: The author's homebrew COSMAC computer system.It contains 2560 bytes of memory and uses a full 16-bit addressdisplay. Important processor and input/output signals arebrought out through the front panel for ease in breadboarding.

Photo 2: Bottom side of the processor board. Six weeks of even-ing work with an OK Tool Hobby Wrap wire-wrap gun and 150feet of wire were needed to complete the connections.

218 May 1980 © BYTE Publications Inc

>:,&&-■' ,«,*>. W.«^«&£- .4 ■' '->^vfeSj

, J I''-

■«•■«>.■

Did you read about the Dungeonmaster who became soenchanted playing a real life version of Dungeons and

Dragons that he disappeared for a month?

You'll be able to hold on to reality just a little better when you playthe Dunjonquest™ computer version, the greatest of all the role-playing

fantasies.

But don't bet on it.

Sit at your computer. You're the hero. Enter theDunjonquest "Temple of Apshai" and into thegreatest fantasy adventure you've ever experienced.The Temple has over 200 rooms and catacombs inwhich lurk more than 30 kinds of monsters andbeasts ready to do you in — in real time—before youcan reach any of the 70 or so treasures waiting for thehero. You may spend days, weeks, months ... the restof your life... striking at the forces of evil, or runningfrom them, or calling on powers you can never com-pletely understand. Always, always demonstrating invarying degrees your strength, constitution, dexterity,intelligence, intuition, the force of your ego.

Unlike chess or bridge or monopoly,this role-playing game — like other goodrole-playing games — is an experiencerather than a game: it is not played somuch as it's lived or experienced. Youralter ego goes forth into the world ofdemons and darkness, dragons anddwarves. Your character will do what-ever you want him (or her or it) to do.

Actual photo of screen during a Dunjonquest game.

In Room 3 in the Temple of Apshai, our hero observestwo treasures unattended by dragons, monsters ordemons... for the moment. He is completely free ofwounds; he is not at all fatigued. He carries 44 pounds ofarmor and 19 arrows in his quiver. He has already slainfive demons. Will he capture the treasures before movingon ... or before the forces of darkness intercept him?

"The Temple... " comes complete with a superblyillustrated 56-page rule book and cassette program,designed to operate with the Level II 16K TRS 80, thePET 32K or the Apple II 48K (Applesoft) computer.Only $24.95 complete, including shipping andhandling on orders placed within the next 30 days.(Apple or TRS 80 disk available for $29.95).

Dunjonquest's "The Temple of Apshai" is guaranteedto be the best version of Dungeons and Dragons/Dragons and Dungeons. It's a product of the two guyswho are Automated Simulations: Jim Connelley andJon Freeman. Jim is a Dungeon Master, running con-tinuous D & D campaigns. He's been a data pro-cessing professional with Westinghouse, GTESylvania, Logisticon... an expert in computer-basedmath-modeling and in simulation of complex phe-nomena. Jon is a game player, designer and author.He's a frequent contributor to Games magazine,- hisbook, "The Playboy Winner's Guide to BoardGames" is a paperback best-seller.

As we said, guaranteed: Guaranteed to be the bestversion; guaranteed that you'll be happy with it.Order now, use it for two weeks. If you don't enjoycompletely this fantasy adventure experience thatgoes beyond all others, send it back to us. We'llrefund your money in full; no questions asked.

Master Charge or Visa card holders: charge "TheTemple of Apshai" to your credit card. Just call ourtoll free number: (800J 824-7888, operator 861 (InCalifornia, call operator 861 (800) 852-7777. InHawaii and Alaska, operator 861 (800J 824-7919) andyou can begin enjoying your Dunjonquest game indays. Or send your check for $24.95* (or $29.95)* to

AutomatedSimulations

A

Dept. 3P.O. Box 4232Mountain View,CA 94040

'California residents, please add 6.5% tax

Circle 133 on inquiry card.

BYTE May 1960 219

cursor's horizontal position (the bitpointer remains the same), but thecursor is moved down one row. Simi-larly, the fourth toggle switch sub-tracts hexadecimal 08 from the bytepointer. This makes the cursor moveone row upward.

Only after the toggle switches havebeen completely scanned are thevalues in the temporary pointerstransferred to the permanentpointers, and the cursor moved to itsnew position. This makes motion onthe diagonal possible without visibleup-and-across motion on the way tothe new position. If all four togglesare actuated, the cursor does notmove. The four motions cancel oneanother before any information istransferred to the permanentpointers.

The fifth toggle switch determineswhether the bit written into the cur-sor position will be a white dot or ablank space.

Operation of Subroutines

Two subroutines accomplish thetransfer of information from tem-porary to permanent pointers and thefinal writing of the cursor bit onto thescreen. If the fifth toggle is actuated,subroutine BNKWRT does the joband writes a 0 (blank) into memory atthe cursor position. If the fifth toggle

Register

High Byte

Low Byte

0

12

Direct-memory-access pointerInterruptprogram counterStack

Direct-memory-access pointerInterruptprogram counterStack

3

pointerMain

pointerMain

45

program counter

program counter

BNKWRT

BNKWRT

6

program counterDOTWRT

program counterDOTWRT

78

program counter

program counter

DELAY

DELAY

9AB

program counterTemporarybyte pointerInter-shiftD storagePermanent

program counterTemporarybyte pointerTemporarybit pointerPermanent

C

byte pointer

byte pointerPermanent

DEF

Blanking

pointer

Delay-timing

constant

bit pointer

Blanking

pointer

Delay-timing

constant

Table 1: Use of COSMAC 1802 16-bit registers

by Video Doodler program.

is not actuated, the job is done byDOTWRT, and the cursor leaves awhite dot behind in memory and onthe screen.

A third subroutine, DELAY, slowsthe process down so that you candirect the cursor intelligently on the

screen. The execution time forDELAY (and thus the speed at whichthings happen) is determined com-pletely by the constant that begins atmemory location 0046. You increaseor decrease this constant to slow theprogram or speed it up.

Text continued on page 224

Photo 3: Component side of the processor board. The videosignal is brought off the board by the miniature 75-ohm coaxialcable.

Photo 4: Display produced using the Video Doodler.isolated dot at the center right is the winking cursor.

The

220 May 1980 © BYTE Publications Inc

ALMOSTPERFEC.

The

MAGfc WAND

is the most powerful,

ine iwij i**i^ w vrwu *«^ is me mosi powenui,most flexible, most reliable, most usable word processingsoftware available for a CP/M-based computer.

Fhat'q nnt hranninn That's hist tpllinn 11 Full screpn tp¥t priitinn Vari

That's not bragging. That's just telling itlike it is.

The MAGIC WAND is the best wordprocessing software ever written for amicrocomputer. It can do more work inless time with higher quality than anyother product you can buy.

The MAGIC WAND is a rock solid pieceof software. The command structure issimple and logical and complete. We havenot tossed in features without thought tothe overall design of the package. Norhave we included any feature that is notthoroughly implemented. The programsare crash-proof and completely reliable.

And the system is supported by what weare told is the best user's manual ever pro-duced for microcomputer software. Itcontains a step-by-step instructional pro-gram designed for the novice. The traineeuses sample files from the system disk andcompares his work to simulated screensand printouts in the manual.

Support doesn't stop when you buy thepackage. As a registered user, you receiveour bi-monthly newsletter which answersquestions, reports upgrades and teachesnew applications of the MAGIC WAND.

It's through a lot of hard work that weare able to offer you a product that is"almost perfect," but we aren't about tostop working until we can say that theMAGIC WAND is perfect.

Full screen text editing

The MAGIC WAND has probably the mostresponsive and easy-to-use editor avail-able for either a serial or DMA terminal. Ituses only single stroke control keys togive command and takes advantage of thespecial function keys on your terminalwhenever possible. In addition, you canset up library files with coded sections thatyou can merge by section name.

Full text formatting commandsThe MAGIC WAND allows you to set theleft, right, top and bottom margins, pagelength, indentation, paragraph indenta-tion, (incuding "hanging" paragraphs),text left flush, right flush, justified (twoways), literal or centered, variable line andpitch settings, variable spacing (includinghalf lines), bold face, underlining (solid orbroken), conditional hyphenation, sub-and superscripting. You may change anyof these commands at run-time withoutreformatting the file.

Merging with external data filesYou may access any external data file,with either fixed length or sequentialrecords. The MAGIC WAND converts therecord into variables that you define andcan use like any other variable. Of course,you may use the data for automatic formletter generation. But you can also use itfor report generation.

Variables

You may define up to 128 variables withnames of up to seven characters. The cur-rent value of a variable may be up to 55characters, and you may print it at anypoint in the text without affecting the cur-rent format. Although the MAGIC WANDstores the variables as strings, you mayalso treat them as integer numbers or for-mat them with commas and a decimalpoint. You may increment or decrementnumeric variables or use them in format-ting commands.

Conditional commands

You may give any print command basedon a run-time test of a pre-defined condi-tion. The conditional test uses a straight-forward IF statement, which allows you totest any logical condition of a variable.You may skip over unneeded portions ofthe file, select specific records to print,store more than one document in a singlefile, etc.

True proportional printing

The MAGIC WAND supports proportionalprint elements on NEC, Diablo and Qumeprinters. Other formatting commands,including justified columns, boldface,underline, etc., are fully functional whileusing proportional logic.

Available on 8" soft-sectored and 5 1 4" Northstar or Micropolis (hard or soft sectored) diskettes, as well asONYX hard disk. Terminals supported include—ADDS. Beehive, Cromemco, Dynabyte. Hazeltine. Heath, Imsai,Intertec, Lear Siegler. Microterm Act V, Perkin Elmer. Sol VDM1. Soroc. TEC. TEI, Televideo. TRS80 Mod II.Vector Graphics, plus a variety of video boards

suxaW busuxess applications, inc.

3220 Louisiana • Suite 205 • Houston, Texas 77006 • 713-528-5158

Circle 134 on inquiry card.

CP/M ib a registered trademark ol Digital Research Corp

BYTE May 1980 221

Circle 135 on inquiry card.

YOU TOO canbecome asuccessfulcomputer

ENTREPRENEUR!

SS*

HOW TO START YOUR OWN SYSTEMSHOUSE is a practical step-by-step guide for theEDP professional or small businessman whowants to enter the micro-computer systems

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Written by the founder of a successful systemshouse, this fact-filled 220-page manual coversvirtually all aspects of starting and operating asmall systems company. It is abundant withuseful, real-life samples: contracts, proposals,agreements and a complete business plan areincluded in full, and may be used immediatelyby the reader.

Proven, field-tested solutions to the manyproblems facing the small systems house arepresented.

From the contents:

• New Generation of Systems Houses • TheSBC Marketplace • Marketing Strategies •Vertical Markets & lAPs • Competetive Posi-tion/Plans of Major Vendors • MarketSegment Selection & Evaluation • Selection ofEquipment & Manufacturer • Make or BuyDecision • Becoming a Distributor • GettingYour Advertising Dollar's Worth • Your Sales-men: Where to Find Them • Product Pricing

• The Selling Cycle • Handling the 12 MostFrequent Objections Raised by Prospects •Financing for the Customer • Leasing •Questions You Will Have to Answer Before theProspect Buys • Producing the System • In-stallation, Acceptance, Collection • Docu-mentation • Solutions to the Service Problem

• Protecting Your Product • Should You StartNow? • How to Write a Good Business Plan •Raising Capital

6th edition, March 1980

220 pages

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Card/*

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Essex Publishing Co. dept. 3

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I would like to order HOW TO START YOUROWN SYSTEMS HOUSE at $36.00 (New Jerseyresidents add 5% sales tax)□ Check Enclosed □ VISA □ Mastercharge

For immediate shipment on credit card orderscall (201) 783-6940

Listing 1: Video Doodler program in machine code for the COSMAC ELF.

Address

00060AOF1316191CIF2225

26282C2F35373A3D4042

444548494A4C

4E4F5153545557

59

5A5C5E60616264

66686A6D6E71727475777A7D80838687898A

Hexadecimal Code

F8

00

Bl B2

B6

B8

A9 AB

F8

01

B9 BB

F8

80

AC AA

F8

28

Al

F8

FF

A2

F8

66

A3

F8

5A

A5

F8

4F

A6

F8

45

A8

D3

72

70

22

78

22 52

C4

C4

C4

F8

01

B0 F8

80

E2

E2

20

A0

E2

20

A0

E2

20

A0

3C

35

30

26

D3

F8

07

BE

2E

9E

3A

48

30

44

D3

89

AB

8A

AC

EB

Fl

5B

E2

30

4E

D3

89

AB

8A

AC

FB

FF

EB

F2

5B

E2

30

59

E2

69

3F

75

F8

FF

AD

ED

F8

00

73

8D

3A

6E

5D

E2

6C

F6

33

89

F6

33

98

F6

33

A7

F6

33

AF

F6

3B

B7

7B

30

B7

BA

8A

F6

33

92

B3 B5

BD

Comments

Initialize high-order registersand byte pointers

Initialize bit pointersInitialize interrupt PCInitialize stack pointerInitialize MAIN PCInitialize BNKWRT PCInitialize DOTWRT PCInitialize DELAY PCBegin executing MAIN PCINTERRUPT

Restore D, X, & PPush P, X, & D onto stackNOP s for sync delay00 AO Re-point R0 to display pagePrepare for first DMA cycleDMA resetDMA resetDMA resetTest for refresh doneGo to return

DELAY

DOTWRT

BNKWRT

MAIN

222 May 1980 © BYTE Publications Inc

Return to MAIN

Load timing constant into RE

Decrement RE

Load RE.l into accumulator

Loop again if not done

Go to return

Return to MAIN

Update byte pointer

Update bit pointer

X = B

Combine bit pointer & screen via OR

Write dot to screen

Go to return

Return to MAIN

Update byte pointer

Update bit pointer

Inverts D via XOR IMMEDIATE

X = B

Combine bit pointer & screen via AND

Write blank to screen

Go to return

Turn CDP1861 on

Skip clearing routine unless INPUT pressed

Point RD to top of display page

X = D

Store 00 on screen & decrement pointer

Load pointer into D

Loop again if not done

Store 00 in last byte of display page

Input toggles

Tests "move right" bit & branches

Tests "move left" bit & branches

Tests "move down" bit & branches

Tests "move up" bit & branches

Tests dot/blank bit

Turn Q on

Go to EXECUTE

Store D in RA.l

Fetch temporary bit pointer

Shift right and test for border cross

Listing 1 continued on page 224

Circle 136 on inquiry card. ^"-^

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DIABLO 16S0

• Prints at 40 cps, using 88, 92, or96 char, metalized printwheels.

• Vertical resolution 1/48"; Horizontal1/120". Capable of proportionalspacing, bidirectional printing, andgraphics under software control.

• Bidirectional normal and direct tabs.Left, right, top and bottom margins.

R.O. $2890.00KSR $3285.00

DIABLO 1640

• Uses plastic printwheel and prints at45 cps. Otherwise, shares identicalfeatures with 1650 including:

— Friction or tractor feed, up to15" wide.

— Cartridge ribbon, fabric or carbon.

R.O. $2745.00KSR $3140.00

• Includes upper/lower case option.

• Bidirectional printing at 150 cps.

• Tractor-feed forms, 3" to 15"wide.

$1599.00

Options:

— Forms length control — $100.00

— Vertical Format Control withCompressed Print — $125.00

Write or Call In for OurFree Catalogue!

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{Shown with optional forms tractor and numerickeypad).

• Prints 10, 12, 13.2, or 16.5characters per inch, upper/lowercase.

• 2, 3, 4, 6, 8, or 12 lines per inch.

• Friction feed, paper width to 15

$999.00

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— Numeric keypad — $80.00

— Adjustable forms tractor —$130.00

1

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High Density Graphics

Parallel, RS-232C, and CurrentLoop interfaces standard.

Double width printing

132/175 or 132/220 columns.

50 to 200+ lines/min., 150/200CPS 9x7/7x9 font or 120/200CPS with 11x9/7x9 font.

9-wire print head, 650 millioncharacter life.

Bi-Directional printing with shortestdistance sensing logic.

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Complete forms control.

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Displays 80 x 24, upper/lower case.

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Reverse video, blinking, underline,112 intensity, protected fields,blank security field.

Transmit character, line, partialpage, page, or unprotected data.

Cursor up, down, left, right, return,home, plus load and read.

$699.00

SOROC

11 7-key detachable keyboard withnumeric cluster and cursor control.

Insert/delete line, insert/deletecharacter.

Underline, blink, reverse, .1/2intensity, protected and blank fields.

Printer port with independent baudrate — prints line, partial or fullscreen.

$1130.00

TELETYPE 43

• Prints 132 columns, upper/lowercase with true descenders.

• 30 character/second print speed.110-300 baud.

• Uses 12" wide by 8.5" pinfeedpaper.

• Print position scale, paper guideand supply rack.

$999.00

i

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TO ORDER: Send check or money order to: MICROMAIL, P.O. SHIPPING: We ship freight collect by UPS when possible. Larger HANDLING: All orders are subject to MICROMAILs handlingBox 3297, Santa Ana, CA 92703. Personal or company checks terminals are shipped by motor freight. Air and express delivery charges. Less than $750.00, add 3%. $750 00 to $2 000 00require two weeks to clear. Terminals in stock are shipped the is available on all products. add 2%. Over $2,000.00. add 1%.

business day after receipt of certified funds. All equipmentincludes factory warranty.

Listing 1

continued:

8E

AA

8F

9A

30

7A

92

19

93

76

94

AA

95

9A

30

7A

98

BA

99

8A

9A

FE

33

Al

9D

AA

9E

9A

30

7D

Al

29

A2

7E

A3

AA

A4

9A

30

7D

]

A7

BA

A8

89

]

A9

FC

08

AB

A9

AC

9A

30

80

1

AF

BA

BO

89

1

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FF

08

■

B3

A9

1

B4

9A

30

83

1EXECUTE

B7

D5

D8

D6

D8 (

BB

31

CO

(

BD

D6

(

BE

30

68

(

CO

D5

(

CI

7A

C2

30

68

Update bit pointer

Put old D back in D & return to shift & test

Increment temporary byte pointer

Shift bit back into other end of bit pointer

Update bit pointer

Put old D back in D & return to shift & test

Store D in RA.l

Fetch temporary bit pointer

Shift left and test for border cross

Update bit pointer

Put old D back in D & return to shift & test

Decrement temporary byte pointer

Shift bit back into other end of bit pointer

Update bit pointer

Put old D back in D & return to shift & test

Store D in RA.l

Fetch temporary byte pointer

Add 08 to D & put sum in D

Update byte pointer

Put old D back in D & return to shift & test

Store D in RA.l

Fetch temporary byte pointer

Subtract 08 from D & put difference in D

Update byte pointer

Put old D back in D & return to shift & test

Generate one "wink" of cursor

Go to M(C0) if Q is on

Call DOTWRT & write on screen

Go to test for clear

Call BNKWRT & write on screen

Turn Q off

Go to test for clear

Text continued from page 220:

One novel effect may be producedby changing the sequence of bytesbeginning at location 0046 to 01, AE,2E, 8E. This permits the program torun at maximum speed. The cursorwill streak across the screen almosttoo quickly for the eye to follow. Asyou flip the toggle switches up anddown, it will paint a crazy-quilt pat-tern across the screen.

To clear the screen, simply holdINPUT depressed while flipping RUNup. This branches to a simple routinethat writes zeroes consecutively inmemory from the top of the displayedpage on down.

Design Storage

Saving a design produced with theDoodler for later display involvesdumping the contents of the displaypage of memory into some mass-storage medium. Lacking a cassettetape interface or some other storage,you will have to step throughmemory and write the hexadecimalcontents of each byte in the page.

Doodle awaylB

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224 May 1980 © BYTE Publications Inc

Circle 137 on inquiry card.

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'TRS-80 Is a trademark of Radio Shack and Tandy Corp. 'Apple Is a registered trademark of Apple Computer Co.Circle 138 on inquiry card.

BYTE May 1980 225

Gook Reviews

TRS-80 AssemblyLanguage Programming

William Barden JrRadio Shack, 1979224 pages, softcover$3.95

"The goal of this book isto take a TRS-80 user

familiar with some of theconcepts of programming inBASIC and introduce him toTRS-80 assembly language."With that statement in thepreface, Mr Barden proceedsto do exactly that. He intro-duces the user of the RadioShack TRS-80 computer tothat mysterious element ofprogramming calledassembly language.

For you old-timers,TRS-80 Assembly LanguageProgramming is a refreshingreview of how we used toprogram way back in thegood old days. For younovices, perhaps discour-aged after trying to debug aBASIC program, this bookis the change of pace youneed. Throw away, or atleast put aside, that BASIC

DIGITAL DATA RECORDERMODEL CC-9B

For five years now, the CC series recorders have been the industryNRZ Asynchronous recorder standard. Now the B model sets a newstandard in stability and reliability with its tachometer feedbackLC stabilized motor circuit.

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CC-9B Model

Price $275.00

CC-9 Model $225.00

DOUBLE DENSITY DISK CONTROLLER

The D4S Disk Controller for Z80 based S-100 systems.Gives you megabytes on line. Controls up to 8 each 5" or 8" drives(even mixed sets) single or double sided when used with CP/M 2.2.This second generation double density controller utilizes the WD1797 chip to read all single and double density formats. Fits NorthStar and we have a CP/M 2.2 for NorthStar or any other Z80 basedSI00 machine. Has on board serial I/O Port for optionalterminal or list device.

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user's manual, type in"SYSTEM" when theprompt character appears,and load that Editor/Assembler or TBUG tapeyou just bought. Now youare going to see what com-puter programming is allabout!

Although the authorstates that the Radio ShackEditor/Assembler packageor its equivalent is not a re-quirement, you will misshalf the fun of reading thisbook if you do not have it.Also, TBUG is recom-mended by the author inorder to fully appreciatesome material.

Barden has developed aunique presentation to intro-duce and explain the generalconcepts of the TRS-80assembly language, themnemonic system for theZ80 microprocessor. I say aunique presentation becausethis is the first assembly-language book which I haveenjoyed reading. Barden isnot averse to injecting alittle humor into his writing.After all, who says that pro-gramming books should beall bits, bytes, and syntaxrestrictions?

Barden begins with thearchitecture of the Z80, itsinstruction set, and itsaddressing modes. He thenproceeds through theEditor/Assembler and theTBUG commands and for-mats in the first section ofthe book.

There is quite a bit ofinformation packed withinthese first eighty-four pages,and it pays to read throughSection 1 with a high-lighting marker in hand. Infact, I skimmed throughthese pages for my firstreading and then rereadthem more carefully thesecond time. This methodtends to fix certain impor-tant details in your mindand will act as a referencingtool.

After you feel confidentwith the introductorymaterial, move on to Sec-

226 May 1980 © BYTE Publications Inc

Circle 139 on inquiry card.

MULTI-USER OASISHAS THE FEATURES PROS DEMAND.

READ WHY.

Computer experts(the pros) usually have bigcomputer experience.That's why when they shopsystem software for Z80micros, they look forthe 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.

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Put it all together and it'seasy to see why the realpros like OASIS. Join them.Send your order today.

CIRCLE WHAT YOU WANT

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Multi-UserOASIS supportsas many as 16 terminalsand can run in as little as56K memory. Or, withbank switching, as muchas 784K.

OASIS IS AVAILABLE FOR: Altos;Bell Controls; Billings; Compucorp;Crornemco; Corvus; Delta Products;Digital Group; Digital Microsystems;Dynabyte; Godbout, IBC; IndustrialMicrosystems; Konan; Micromation;Micropolis; North Star; Onyx; SDSystems; Tarbell; Thinkertoys;TRS 80 Mod. II; Vector GraphicVorimex; X Comp; and others.

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 the

Product

Price

with

Manual

ManualOnly

OPERATING SYSTEM

(Includes:EXEC Language;File Management;User Accounting:Device Drivers;Prim Spooler:General TextEditor; etc.)SINGLE-USERMULTI-USER

S150

350

S17.5017.50

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 &SCRIPT PROCESSOR

150

15.00

DIAGNOSTIC «CONVERSION UTILITIES

(Memory Test;Assembly Language;Converters; FileRecovery; Disk Test;File Copy fromother OS; etc.)

100

15.0C

COMMUNICATIONSPACKAGE

(Terminal Emulator:File Send & Receive)

100

15.00

PACKAGE PRICE

(All of Above;

SINGLE-USER

MULTI-USER

500850

60.0060.00

FILE SORT

100

15.00

COBOL-ANSI '74

750

35.00

I Order OASIS from:

| Phase One Systems, Inc.

■ 7700 Edgewater Drive, Suite 830

J Oakland, CA 94621

' Telephone (415) 562-8085I TWX 910-366-7139

NAME

STREET (NO BOX-)CITY

.ZIP.

STATE

AMOUNTS

(Attach system description;

add S3 for shipping;

California res dents add sales tax)

□ Check enclosed Q VISA

□ UPS C.O.D. □ Mastercharge

Card Number

Expiration Date

Signature

BYTE May 1980 227

Hon 2. Barden not onlyexplains the how and thewhy of assembly language,but does so with usefulexamples of assembly-language coding. When heexplains how to move data,he does it by coding the in-structions and discussing thepertinent background.Arithmetic and comparisonoperations, logical and bitoperations, shifting, strings,and tables are explained andpresented with appropriatecoding. If you have TBUG

or Editor/Assembler, youcan code along with the textand actually see the opera-tions being executed. Thisinteractive approach workswell.

In TRS-80 AssemblyLanguage Programming,Barden handles the discus-sion of input/output (I/O)operations in an easilyreadable, yet informativefashion. After you completethis phase of your educa-tion, the mystery ofassembly language magically

evaporates, and you areready to tackle somesophisticated assembly-language programming.

But that's not all. Bardenties together most of theloose threads by includingsome interesting and usefulsubroutines. If you want aquick routine to fill a blockof memory with any given8-bit value or move the con-tents of a block of memoryfrom one area to another,you need only assemble thesubroutines already coded

Future World-Today

i, *r'j:'« i

Instant Nationwide Communications

A Micromodem 100 in your S-100 bus adds: Automatic TimeSharing, Nationwide Communications, Remote Data BaseAccess, TWX Simulation, Branch Office Communications,and much, much more. The D.C. Hayes Associates Micro-modem 100 is compatible with 300 baud modems and theproposed IEEE S-100 bus standard. It is built to the highestquality standards and tested with automated equipment toassure reliability. Whether built-in to original equipment, oradded on from your local computer store, the Micromodem100 adds new communications capabilities to every S-100bus computer.

D.C. Hayes Associates, Inc.

MICROCOMPUTER PRODUCTS

10 Perimeter Park Drive, Atlanta, Georgia 30341 (404) 455-7663

•Registered trademark of Apple Computer, Inc. MicromodemII is a re<jis

Irademark of D.C. Hayes Associates

for you and presented in thebook.

Some arithmetic sub-routines are also given: add-ing or subtracting operandscontaining up to 256 bytes,and multiplying or dividing16-bit numbers. The com-pare subroutine is usefulsince it compares two 8-bitoperands in true algebraicfashion. A routine for con-verting an 8-bit value intotwo American StandardCode for Information Inter-change (ASCII) characters isincluded, as is a search sub-routine. Finally, threesubroutines that operate in amanner similar to the SET,RESET, and POINTstatements in BASIC aregiven in the book.

Barden offers four com-plete assembly-language pro-grams to start your programlibrary off on the right foot.These perform the functionsof writing data to the screen(good for looking at thecontents of memory loca-tions), moving patterns athigh speed (great foranimated graphics), agraphic bubble sort (goodfor demonstrations), and aprogram to play music viathe cassette output port.

The appendices include alisting of the Z80 instructionset and a listing of the Z80op codes. (For quickreference to Z80 mnemonics,Zilog offers the Z80-CPUProgramming ReferenceCard, which I have foundmore convenient to use thanflipping through the pages ofa book.)

One further note: WilliamBarden is also the author ofThe Z80 MicrocomputerHandbook (Howard WSams Co Inc, 1978), whichtakes the Z80 software a fewsteps deeper into theassembly-language forest.

So, what can you get for$3.95 in addition to Barden'sexcellent introductory textdealing with Z80 assembly-language programming?Quite possibly you will get ahard-to-shake bite from theassembly-language bug.B

Len Gorney

Box 91 RR 5

Salisbury Rd

Clarks Summit PA 18411

228 May 1980 © BYTE Publications Inc

Circle 141 on inquiry card.

Your Discount

STRUCTUREDSYSTEMS

Software Source!

Cash Price/Manual

GENERAL LEDGER - Interactive andflexible system providing proof and reportoutputs. Customization of COA created inter-actively. Multiple branch accounting centers.Extensive checking performed at data entryfor proof, COA correctness, etc. Journalentries may be batched prior to posting.Closing procedure automatically backs up in-put files. Now includes Statement of Changesin Financial Position.Requires CBASIC-2 $749/$25

ACCOUNTS RECEIVABLE - Openitem system with output for internal agedreports and customer-oriented statementand billing purposes. On-Line Enquiry permitsinformation for Customer Service and Creditdepartments. Interface to General Ledgerprovided if both systems used.

Requires CBASIC-2 $749/$25

ACCOUNTS PAYABLE - Providesaged statements of accounts by vendor withcheck writing for selected invoices. Can beused alone or with General Ledger and/orNAD. Requires CBASIC-2

$749/$25

PAYROLL - Flexible payroll systemhandles weekly, bi-weekly, semi-monthlyand monthly payroll periods. Tips, bonuses,re-imbursements, advances, sick pay, vacationpay, and compensation time are all part ofthe payroll records. Prints government re-quired periodic reports and will post to multi-ple SSG general ledger accounts.

Requires CBASIC-2 $749/$25

INVENTORY CONTROL SYSTEM -Performs control functions of adding anddepleting stock items, adding new items anddeleting old items. Tracks quantity of itemson hand, on order and back-ordered. Optionalhard copy audit trail is available. Reportsinclude Master Item List, Stock Activity,Stock Valuation and Re-order List

Requires CBASIC-2 $449/$25

ANALYST - Customized data entryand reporting system. User specifies up to 75data items per record. Interactive data entry,retrieval, and update facility makes informa-tion management easy. Sophisticated reportgenerator provides customized reports usingselected records with multiple level break-points for summarization.

Requires CBASIC-2 $199/$15

LETTERIGHT - Program to create,edit and type letters or other documents.Has facilities to enter, display, delete andmove text, with good video screen presen-tation. Designed to integrate with NADfor form letter mailings.Requires CBASIC-2 $169/$25

NAD Name and Address selectionsystem — interactive mail list creation andmaintenance program with output as fullreports with reference data or restrictedinformation for mail labels. Transfer systemfor extraction and transfer of selected recordsto create new files.

Requires CBASIC-2 $89/$20

QSORT — Fast sort/merge program forfiles with fixed record length, variable fieldlength information. Up to five ascending ordescending keys. Full back-up ofinput files created $89/$20

Circle 142 on inquiry card.

PEACHTREE

GENERAL LEDGER, $1000 $749/30ACCTS. PAYABLE, $1000 $749/30ACCTS. REC., List $1000 $749/$30INVENTORY, List $1200 $749/$30MAILING ADDRESS, $800 $599/$30

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PAYROLL SYSTEM $499/$35

INVENTORY SYSTEM... $499/$35

JOB COSTING - Designed for gen-eral contractors. To be used interactively withother GRAHAM-DORIAN accounting packagesfor tracking and analysing expenses. Userestablishes customized cost categories and jobphases. Permits comparison of actual versusestimated costs. Automatically updates GRA-HAM-DORIAN general ledger or runs as standalone systems. Reguires CBASIC-2. Supplied insource $849/$35

APARTMENT MANAGEMENTSYSTEM — Financial management systemfor receipts/security deposits of apartment pro-jects. Captures data on vacancies, revenues,etc. for annual trend analysis. Daily report showslate rents, vacancy notices, vacancies, incomelost through vacancies, etc. Reguires CBASIC2.Supplied in source $499/$35

MICROSOFT

BASIC-80 - Disk Extended BASIC,ANSI compatible with long variable names,WHI LEAVEND, chaining, variable

length file records $269/$25

BASIC COMPILER - Language com-patible with BASIC-80 and 3-10 times fasterexecution. Produces standard Microsoft re-locatable binary output. Includes Macro-80.Also linkable to FORTRAN-80 or

COBOL-80 code modules $325/$25

FORTRAN-80 - ANSI 66 (except forCOMPLEX) plus many extensions. Includesrelocatable object compiler, linking loader,library with manager. Also includesMACRO-80 (see below) $389/$25

CBASIC-2 Disk Extended BASIC -Non-interactive BASIC with pseudo-codecompiler and runtime interpreter. Supportsfull file control, chaining, integer andextended precision variables, etc.$89.95/$15

MICROPRO

SUPER-SORT I - Sort, merge, extractutility as absolute executable program or link-able module in Microsoft format. Sortsfixed or variable records with data in binary,BCD, Packed Decimal, EBCDIC, ASCII,floating, fixed point, exponential, fieldjustified, etc. Even variablenumber of fields per record! .... $219/$25

WORD-STAR - Menu driven visualword processing system for use with standardterminals. Text formatting performed onscreen. Facilities for text paginate, page num-ber, justify, center and underscore. User canprint one document while simultaneouslyediting a second. Edit facilities include glob-al search and replace. Read/Write to othertext files, block move, etc. Requires CRTterminal with addressable

cursor positioning $395/$40

WORD-STAR/MAIL-MERGE -Asabove with option for production mailing ofpersonalized documents withmail list from Datastar or NAD . . $525/$25

OSBORNE

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All packages available in 8" CP/M™ and 51A" CP/M™ FOR North Star, Micropolis,Vector Graphic, SuperBrain, and others.

SHIPPING AND INSURANCE: Add $2.50 per order. All prices subject to change and all offers subject to withdrawal without notice.Prices in this ad are for prepaid orders. Slightly higher prices prevail for other-than-prepaid orders, i.e., C.O.D., credit card, etc.

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Glubs and Newsletters

Newsletter for

Ohio Scientific

Users

The OSI Users' Indepen-dent Newsletter is edited,published, and written byCharles Curley, 6061 LimeAve, Number 2, Long BeachCA 90805. A year's subscrip-tion is $10 for six issues.The newsletter includes

articles on software, hard-ware, bugs and fixes, andreviews of items of interestto OSI users. Articles arewelcome from enthusiasticowners and users.

Salem, Oregon AreaComputer Club

Club membership is opento all those that are in-

terested in using microcom-puters for fun and business.Membership dues are $5 peryear. The club meets thefirst Monday of each odd-numbered month atMcKinley CommunitySchool, 461 McGilchrist St,Salem, Oregon. On even-numbered months, theymeet at Computer PathwaysUnltd Retail Store, 831 Lan-

caster Dr, Salem, Oregon. Amonthly newsletter ispublished. Each meetingfeatures a presentation by aclub member or invitedguest. For information, con-tact Salem Area ComputerClub, c/o Doug Walker,4554 Jan Ree Dr NE, SalemOR 97303.

North London HobbyComputer Club (NLHCC)

The NLHCC has sched-uled their meetings for thenext 3 months. The themefor the May meeting is"Computer-Aided Instruc-tion." The meeting will beheld May 7 at 7 PM in theStudents Common Room inthe Polytechnic of NorthLondon. On June 4, themeeting is entitled "TheHouse Computer." Julythird's meeting is on "ThePersonal Computer andRestel/Teletext." ContactNLHCC, Holloway, LondonN7 8DB, ENGLAND.

TRS-80 Users Groupof Sacramento

The TRS-80 users groupof Sacramento meets at theSacramento Country BranchLibrary, 2443 Marconi Blvd(Marconi and Fulton),Sacramento, California,from 7 to 10 PM as called.For more information, con-tact the TRS-80 Users Groupof Sacramento, POB 255704,Sacramento CA 95825.

University of

New Hampshire

Computer Services

Newsletter

On Line is a well-pro-duced newsletter coveringsoftware programs,schedule's of events andother activities of interest tostudents in the computerprograms. For more infor-mation, contact ComputerServices, University of NewHampshire, Kingsbury Hall,Durham NH 03824.

230 May 1980 © BYTE Publications Inc

BUY ONE of these

great professional books and

ET ONE FREE

(values up to $60.00)

when you join the

COMPUTER. PROFESSIONALS'BOOK CLUB

Choose any one of these books at the special club discount, andselect any other as your gift Free of Charge when you enroll:

AUTOMATIC DATA PROCESSING HANDBOOK

Edited by The Diebold Group, Inc.

168/075 Pub. Pr., $38.95 Club Pr., $25.75

PROGRAMMING LANGUAGES By A. B. Tucker, Jr.654/158 Pub. Pr., $22.00 Club Pr., $16.50

MINICOMPUTER SYSTEMS, 2nd Ed. By R. H.

Eckhouse

787/026 Pub. Pr., $21.95 Club Pr. $16.50

MICROCOMPUTERS/MICROPROCESSORS:Hardware, Software & Applications By J. L.

Hilburn & P. N. Julich

771/499 Pub. Pr, $22.50 Club Pr., $16.50

MICROPROCESSOR APPLICATIONS MANUAL

By Motorola, Inc.

435/278 Pub. Pr., $38.00 Club Pr., $26.50

THE 8080A BUGBOOK: MICROCOMPUTER IN-TERFACING AND PROGRAMMING By P. R.

Rony, D. G. Larsen & J. A. Titus

783/845 Pub. Pr., $9.95 Club Pr, $8.45

MICROCOMPUTER-BASED DESIGN By J. Peat-man491/380 Pub. Pr, $26.50 Club Pr, $18.95

DATA BASE DESIGN By G. Wiederhold701/30X Pub. Pr., $24.50 Club Pr., $18.25

PRINCIPLES OP INTERACTIVE COMPUTERGRAPHICS, 2nd Ed. By W. M. Newman & R. F.Sproull463/387 Pub. Pr $24.95 Club Pr, $19.95

PROGRAMMING FOR MINICOMPUTERS By J. C.

' Cluley785/49X Pub. Pr, $17.50 Club Pr, $13.50

REAL-TIME PROGRAMMING WITH MICRO-COMPUTERS By R. C. Turner786/372 Pub. Pr, $16.95 Club Pr, $13.95

MEMORY DESIGN: Microcomputers and Main-frames By Electronics Magazine191/549 Pub. Pr., $18.50 Club Pr., $15.50

HOW TO DESIGN AND BUILD YOUR OWN CUS-TOM TV GAMES By D. L. Heiserman786/585 Pub. Pr., $14.95 Club Pr, $11.95

HANDBOOK OF OPERATIONAL AMPLIFIERCIRCUIT DESIGN By D. F. Stout, edited by M.Kaufman617/97X Pub. Pr., $29.95 Club Pr., $17.50

ANALOG SYSTEMS FOR MICROPROCESSORSAND MINICOMPUTERS By P. H. Garrett786/496 Pub. Pr., $18.95 Club Pr., $14.95

ENCYCLOPEDIA OF COMPUTER SCIENCE

Edited by A. Ralston & C. L. Meek

769/01X Pub. Pr., $60.00 Club Pr, $39.95

MICROPROCESSOR AND MICROCOMPUTERSYSTEMS By G. V. Rao783/659 Pub. Pr., $24.50 Club Pr, $19.50

THE Z-80 MICROCOMPUTER HANDBOOK By W

Barden, Jr.

784/914 Pub. Pr., $8.95 Club Pr., $7.60

Why YOU should join now!

• BEST BOOKS IN YOUR FIELD —Books are selected from a widerange of publishers by expert editors and consultants to give youcontinuing access to the latest books in your field.

• BIG SAVINGS — Build your library and save money too! We guaran-tee savings of at least 15% off publishers' list prices on every book.Usually 20%. 25% or even higher!

• BONUS BOOKS —You will immediately begin to participatein our Bonus Book Plan (hat allows you savings between70-80% off the publisher's price of many books.

• CONVENIENCE —14 times a year you receive the Club BulletinFREE, fully describing the Main Selection and alternate selections,together with a dated reply card. If you want the Main Selection, yousimply do nothing —it will be shipped automatically. If you want analternate selection —or no book at all —you simply indicate it on theregular reply card and return it by the date specified. You will have atleast 10 days to decide. If. because of late mail delivery of the Bulletinyou should receive a book you do not want, just return it at the Club'sexpense.

As a Club member, you agree only to the purchase of four books(including your first selection) over a two-year period.See us at NCC, booth 1215

Computer Professionals' Book Club

P.O. Box 582, Hightstown, New Jersey 08520

Pleose enroll me as a member and send me the Iwo books indicated, billing me lor my lirstselection only ct the discounted member's price, plus local lax, postage and handling. Itnot satisfied. I may return the books within todays and my membership will be canceled. Iagree to purchase a minimum of 3 additional books during the next 2 yedrs as outlinedunder the club plan described in this ad. Membership in the club is continuous butcancellable by me any time otter the tour book purchase requirement has been fulfilled

Write Code # otFREE selection here

Write Code # olFIRST selection here

Orders from outside the U.S. must be prepaid with international money orders in US.

dollars

Charge my □ VISA U MASTER CHARGE' Exp. Date

Credil Card # -MC Bank #

Signature

Name

Address

City, Slate, Zip .

Corporate Affiliation

This order subject to acceptance by McGraw-Hill All prices subject to change withoutnotice. Offer good only to new members. A posloge and handling charge is added to oilshipments. P39458

BYTE May 1980 231

Central Oklahoma

Amateur Computing

Association (CENOACA)

CENOACA meets thesecond Saturday of eachmonth at the OSU TechnicalInstitute, 900 N Portland,Oklahoma City, Oklahoma,at 10 AM. Their purpose isto acquaint beginners withpersonal computing and in-crease their knowledge ofspecial interest areas, in-cluding SwTPC and 6800systems. Their newsletter,CENOACA Newsbits, ispublished on an irregularbasis. Contact CENOACA,POB 2213, Norman OK73070.

Another Group in Florida

The Space CoastMicrocomputer Club meetson the fourth Thursday ofeach month at 7:30 PM inthe Merritt Island PublicLibrary Auditorium. Theyare affiliated with the JFKennedy Space Center at

Cape Canaveral. The grouppublishes Enterprise, amonthly newsletter. Theprimary interests are Z80,8080, and S-100 systems.Dues are $5 per year, andinquiries should be sent toRay O Lockwood, 315 InletAve, Merritt Island FL32952.

APL Newsletter

A quarterly newsletterdescribing tools, techniques,services, and containinggeneral news of interest toAPL users, is being pub-lished by Southwater Corp,2348 Whitney Ave, MtCarmel CT 06518. Subscrip-tions are $6 annually and re-quests should be sent toAPL Market Newsletter, atthe above address.

Newsletters on the UCSDPascal System

The Institute for Informa-tion Systems is publishing

newsletters describing theUCSD Pascal Systemdeveloped by the Universityof California, San Diego.For more information, con-tact the Institute for Infor-mation Systems, mail codeC-021, University of Califor-nia, San Diego, La Jolla CA92093.

Apple Users Group

The Goldcoast ComputerApple II Users Club desiresadditional members. Thegroup publishes a monthlynewsletter with program-ming tips, and they have alibrary selection of over1000 programs. Send fordetails: Florida's GoldcoastComputer Apple II UsersClub, 133 Brenda St, MiltonFL 32570.

Feedback From Fujitsu

Feedback From Fujitsu is a

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newsletter from FujitsuLimited, Japan's largest com-puter manufacturer. It con-tains items concerningdiscoveries and generalbusiness news of Japan'sstrides in the computer in-dustry. For more informa-tion, contact Feedback FromFujitsu, Ruder and Finn Inc,110 E 59th St, New YorkNY 10022.

Association for

Computers and the

Humanities

This internationalorganization is devoted tothe study of computer ap-plications in language andliterary studies, history,musicology, the visual arts,cultural anthropology, andother related social sciences.Members of the associationare entitled to discount atthe International Conferenceon Computers and theHumanities and the meetingsof the Association forLiterary and Linguistic Com-puting. The annual dues are$15, and a quarterlynewsletter is available for$15 per year. For details,write Association for Com-puters and the Humanities,Queens College, FlushingNY 11367.

Computers andGambling Magazine

This quarterly magazine isoriented toward computerhobbyists interested in usingcomputers for all types ofhandicapping systems, cardcounting systems, andtechniques for stock andfuture markets investments.Articles describe productsand techniques for the com-puterized gambler, andadvertising of products andpersonal computers is in-cluded. Sample issues areavailable for $1. Subscrip-tions are $5 per year andmay be obtained by writingto Joe Computer, 22713Ventura Blvd, Suite F,Woodland Hills CA91364.■

232 May 1980 © BYTE Publications Inc

Circle 145 on inquiry card.

EVERY TRS-80MODEL II NEEDS

DataBank

Data Management & Reporting System

"Deposit" data, or make almost instantaneous "withdrawls" with DataBank!

A complete modular software system, DataBank provides the new Model II user and professional alike with theability to quickly and easily generate custom information systems in minimum time. Using Hash Access torecords, DataBank gives superfast response time, minimum system overhead, and the facility to deal with verylarge numbers of records. Fast assembler sorting optimizes Model II's performance. DataBank includes:

Configuration Utilities: interactive programs which guideyou step by step through creating definitions for your filesystem, formatted entry and display screens and reports.These utilities automatically create the information tableswhich control the rest of DataBank's operation.

User Subroutines: a comprehensive library of software "blackboxes" that you can use to extend DataBank where needed toproduce custom applications programs. A simple GOSUB cancall records from disk by key, fielded and ready for evaluation,inquiry or update. Or, display a prompted input of definedlength and data type anyplace on the screen. More...

Run Time Routines: the programs you will use in day to day

operation to initialize the system, display a master menu ofoptions, and load DataBank's file maintenance and reportprograms and other programs which you may create to workwith your data. As soon as you specify your file contents, dataentry can begin immediately!

Report Generator: an easy to use, fast, flexible reportingsystem. You create the report headings and formats using theConfiguration Utilities. Then, Report Generator reads thespecifications, and draws information from your records toproduce the finished printouts. Has range and selectcapabilities, and assembler sorting on any field in your filedefinition.

The uses of DataBank are unlimited... inventory, personnel, mailing lists, customer/client files, medical/dentalrecords, membership or subscriber lists, and with your own programming added the possibilities go on and on.

DataBank $189.00

DataBank Inventory, Order Entry, Accounts Receivable/PayablePoint of Sale, General Ledger and Payroll available soon!

Index Sequential Data Management System w/Report $179.

An ISAM based system for the TRS-80 Model IWe have Accts. Receivable, Inventory, Gen. Leg. & Payroll for Mod I

DEALER AND SYSTEMS HOUSE INQURIES INVITED

Call or Write for Information:

DATA ACCESS CORPORATION

4221 Ponce De Leon Blvd., Coral Gables, Florida 33146 / (305) 446-0669

*TRS-80 is a registered trademark of Tandy Corporation

BYTE May 1980 233

BYTE's Bits

Observations from

BYTE's Ongoing

Monitor Box, The BOMB

As the card says, BYTE'sBOMB is your direct line tothe editor's desk. Ever sincethe third issue of BYTE(November 1975), BYTE'seditors have used the BOMBas an important source ofinformation on how readersreact to our magazine.Therefore we thank thereaders who have mailed theBOMB card to us and in-cluded their comments.

Occasionally we like toshare with you some of themore interesting responsesreceived on these cards. Themost pictorial BOMB cardin recent memory came froma reader in Hackensack,New Jersey, shown frontand back in photos 1 and 2.It seems our friend in NewJersey was generally pleasedwith our January 1980 issue.

Regretfully not all of ourreaders have been as wellpleased. On one February1980 BYTE BOMB card

most of the articles wererated as being of poor quali-ty, and a single word ap-peared in the "Comments"section: "PHOOEY." Yetanother BOMB card forFebruary said: "Your bestissue in my 3 years!!" Clear-ly, a split decision.

If you have wonderedwhen we stop acceptingBOMB cards for a givenissue, we cut off tabulationduring the second week ofthe month after the coverdate of an issue.

If you have never sent ina BOMB card, but intend todo so, please observe thefollowing points. The cardshould be sent to our officesin Peterborough, NewHampshire. The card ispresently not postpaid, but$0.10 US postage will sufficefor most readers. The card isintended to record your sub-jective opinion, so just writeyour reaction, and put anyspecific comments on thebottom of the card. You arefree to remain anonymous,but you may put your name

and address on the card ifyou wish. In any case, let-ting us know your responsesto our work helps us towork better. . . .RSS

The Largest ComputerStore in America?

What is the largest per-sonal computer store inAmerica 7 The answer tothat question is debatable,but on the East Coast, it'sprobably NEECO's (NewEngland Electronics Com-pany Incorporated) newfacility in Needham,Massachusetts. The9000-square-foot showroomwas filled with a variety ofhardware and software onour recent visit. PresidentRobert Crowell told usabout their new nationwidedistribution subsidiary, call-ed Microamerica, which wasannounced last fall and car-ries most of the major com-puter product lines.

We have noticed amarked increase in the

MOC

J§?"!

\ .1, <■,„■ lj in ''.I li '■ ■ ■ ' - '■" "- ' '••■- •-■fn-lAj 'f*> t I

T&Si^&UZMmt.. c:etm»S 'Ate

SQ#if ,<r?C/Z(i

Photo 1

Photo 2

number of large computerstores like Bob Crowell'swith diverse product lines.This supermarket-like ap-proach can be beneficial tothe industry when combinedwith personal service tocustomers—a vital ingredi-ent to any store's success.In the West, things arealso humming in the per-sonal computer store field.Micro-Age in Tempe,Arizona, is a good example.Run by Jeff McKeever andAlan Hald, Micro-Age hasbeen expanding. We werefavorably impressed by theirfacility and by their ap-proach to the market duringa recent visit. . . .CM

Texas Instruments Has

an Award Winning

Bubble Memory

Texas Instruments hasbeen awarded the 1979 In-formation Product of theYear Award for its Model763 Bubble-Memory DataTerminal and Model 765Portable Bubble-MemoryData Terminal. Both ter-minals have a full,128-character, alphanumerickeyboard. Up to 80,000characters can be collectedand stored in the nonvolatilebubble memory, then trans-mitted at rates from 110 to9600 bits per second (bps) toa host computer system.Both units have a quiet30-character-per-second (cps)print speed and built-inacoustic coupler modem.

A bubble memory is asmall electromagnetic circuitthat stores digital informa-tion by changing themagnetic polarity of a thin,crystalline film. The bubblesare cylindrical magneticislands polarized in a direc-tion opposite from that ofthe film. Bubble memoryhas no moving parts, and,because it works magnet-ically, retains informationwhen the power is turnedoff. It offers higher access

234 May 1980 © BYTE Publications Inc

ttl

II

THE CREATOR

By Complete Business Systems, inc.Software Division

High level language program generator developscomplete programs in "Basic".

Enables ANYONE to write complete, running, debuggedBASIC LANGUAGE Programs in 35 to 40 minutes with NOPRIOR PROGRAMMING KNOWLEDGE OR ABILITY.

Now available for TRS-80®, TRS-80 Model II®, Apple ll®,Tandy 10®, Adds System 70 or 75®.

IF you are one of the many who bought a micro-computer in the belief that with just a little studyingyou could write your own programs, you now knowthat you can't.

IF you, as a businessman, thought you could havestock software modified at a reasonable cost withreasonable results, you know that's not possible either.

IF you are a hobbyist getting tired of the untoldhours it takes to write a program, only to find it takesmore hours to debug than to write .. .

IF you are a skilled programmer you don't have to bereminded of the repetitious time spent on each newapplication.

IF you have left your micro-computer sitting some-where gathering dust... meet "THE creator®".

"THE CREATOR®" is not just another data basegenerator!

"THE CREATOR®", at your direction, makes completerunning programs that are thoroughly documented,easy to modify at any time by YOU!

"THE CREATOR®" cuts programming time up to 90%for a skilled programmer.

"THE CREATOR®" will make anyone a skilled pro-grammer in 30 to 35 minutes!

"THE CREATOR®" does the work! You answer thesimple direct questions and "THE CREATOR®" CREATES. . . AND ALL IN BASIC LANGUAGE.

After "THE CREATOR®'it be modified?

has produced a program, can

A. Yes, the resulting program is modular, fully documentedand readily accessible for alterations or deletions.

O. Does the program created use so much disc spacethat there is very little space left for record storage?

A. No, the code produced is extremely compact despite com-plete documentation. If requested "THE CREATOR®" willeven "pack" or compress information. You may even deletethe "remarks" making it even more space efficient.

O. Must I be expert or even conversant with BasicLanguage?

A. No, all questions to and answers from the operator requireno computer language knowledge, simple every day Englishwill do.

0. What about math ability?

A if you can count your fingers and toes, you'lproblems.

have no

Will the programs which I produce with "THECREATOR®" be bulky, slow or amateurish?

No, the resulting programs will be sophisticated and ex-tremely fast operating. For example, should you create amailing list or inventory program, the time for any recordto be retrieved and displayed from a full disc would take amaximum of 1 second.

0. Must the programs produced conform to a pre-determined format and file length?

A. No, you determine format and file size to fit your require-ments. You may have as many as 22 fields or as few as 1.

0. Can l develop my own business programs?

A. For the most part, yes.

0. What are the limitations? What programs can I pro-duce with "THE CREATOR®"?

A Your own ingenuity and hardware limitations.

0. WIN future versions of "THE CREATOR®" make mypresent copy obsolete?

A. The purchase price includes your original diskette and userinstructions. Your program is registered in your name. Fora period of one year from the date of purchase you will beentitled to receive FREE any improvements or modifica-tions. The only expense to you will be a new diskette charge(if applicable), packaging and mailing.

TECHNICAL ASPECTS

• Record access by a hashing algorithm guaranteeingfast record retrieval.

• Duplicate keys permitted.

• Record deletion automatically supported.

• Record access and file maintenance is user trans-parent.

• Minimal disc overhead since there is no specialassembly language routine called. No"Basic"overhead.

• Programs produced can be transported between6800, 6502, 8080, Z80, 8085, 8086 and Z8000 basedsystems.

• Can be used with Micro-Soft Basic and CP/M systems.

• On TRS-80 has automatic blocking for maximumnumber of records per disc.

• complete file maintenance including up-date of anyrecord in any field, delete and add new records evenwith duplicate key.

we are seeking qualified dealers and distributors tohandle our growing software lines. Address inquiries,on your company letterhead, to: Complete BusinessSystems, inc., Software Division, 9420 w. Foster Ave.,Chicago, Illinois 60656.

Enclosed is my check (or money order) in the amount of $250.00.Please send me my serial numbered, registered copy of "THECREATOR" as soon as my check clears. (No wait for Certifiedchecks, bank checks or money orders.) Sorry, no credit cardsaccepted.

(Please print)_

Full name

Address

City

State,

Apt.# ._ Zip.

Computer make.

.Model

Circle 147 on inquiry card.

BYTE May 1980 235

speeds, smaller size, and lessweight and power consump-tion over paper-tape,cassette and floppy-disksystems. Bubble memoryterminals can access any in-dexed record in memory inless than 15 ms (ie: 10 timesfaster than a floppy disk). Ifthe data location isunknown, the character-string-search speed is 1000cps, about 4 times the speedof a cassette search.

For more information,contact Texas Instruments,POB 1444, M/S 7784,Houston TX 77001.

The Fifth Annual

California Computer

Swap Meet

The Fifth Annual Califor-nia Computer Swap Meetwill be held on June 1, 1980,from 10 to 6 PM at the San-ta Clara County Fairgrounds(344 Tully Rd, San JoseCA). Last year's event, heldin September at the San

Mateo County Fairgrounds,was attended by over 3000buyers.

Personal computing hard-ware and software will besold by individuals, com-puter manufacturers, andcomputer stores. New soft-ware and hardware, as wellas used, will be offered byvendors and individuals whohave cleaned out their backrooms and garages for theevent. Admission is free tobuyers. Contact the FifthCalifornia Computer SwapMeet, POB 52, Palo AltoCA 94302, or call415-324-2404.

InexpensiveCommunicationsVia Meteor Trails

The hundreds of millionsof meteors that enter theearth's atmosphere everyday leave in their wake avery inexpensive communi-cations medium—the meteortrail. This band of ionized

particles is an effective alter-native to satellites for com-munication. Meteor trailscan be used to relay dataconcerning icebergs, pollu-tion, earthquakes, and oilreserves, and can linkremote villages with distantsources of supplies andemergency assistance.

Meteor burst transmissionhas proven reliable and cost-effective for the snowtelemetry program operatedby the US Department ofAgriculture's Soil Conserva-tion Service. By transmittingsnowfall data from remotelocations, the program haseliminated costly manualmeasurements.

Meteor burst transmissionsystems work in severalstages. Remote sensorsgather data while amicroprocessor-controlledstation emits a continuousradio signal, which bouncesoff a meteor trail wheneverone occurs within range.When this signal reaches atransceiver at a remote site,

Dealerships Available

MULTI TERMINALSMALL BUSINESS COMPUTERS

IBC System 40 with 64 K byte memory, 2M byte * up to 6 CRT's/printers can operate

disk storage, cabinet, and multi-user operat- Independently and simultaneously.

ing system with BASIC "4700 System 40 has dynamic memory al-

Addltional 64K byte memory (128 total) 700 location, reentrant code, and vec-

Addltlonal 2M byte disk storage 1950 tored Interrupt. Operating system runs

Additional 20M byte disk storage (Winchester) 4000 foreground, background, Interactive,

CRT Terminal 895 and batch. BASIC has multiple key

Matrix Printer (150 cps) 1895 ISAM.

Character Printer (55 cps) 2695

• Multi-user wordprocessing concurrent

'Dealer Prices with data processing.

'Integrated Business Computers

22010 Wilmington Ave., Suite 306, Carson, CA90745 (213) 518-4245

data is transmitted via themeteor trail to the centralstation.

For more information,contact SRI International,333 Ravenswood Ave,Menlo Park CA 94025. ■

BYTEs Bugs

Escher'sNationality

I was interested in theFebruary 1980 BYTE coverand in Carl Helmers'editorial concerning theEuler Problem ofKonigsberg. I immediatelynoticed when I received theissue the similarity of thecover painting to Escher'swork. However, I must takeargument concerning thestatement that Escher was aSwiss artist.

Maurits C Escher wasborn on June 17, 1898 inLeeuwarden, Netherlands,and died March 27, 1972 inLaren, also in theNetherlands. He was in facta Dutchman whose worksare almost revered today inthe Netherlands. I certainlycommend artist RobertTinney for combining twoof Escher's more famousprints Drawing Hands, fromJanuary 1948, and Reptiles,from March 1943. However,the sequence of reptiles inEscher's original work camearound and completed thecycle, by returning to theflat paper, whereas these"dragons" seem to disappeararound the corner.

Naturally, the Towers ofHanoi did not go unnoticedeither.

My commendation to MrTinney, but I think that thehistory of Escher, who mayhave been the world'sgreatest graphic artist,should be given correctly.

Neal Koss3440 Lomita BlvdSuite 452Torrance CA 90505

236 May 1980 © BYTE Publications Inc

Circle 148 on inquiry card.

For the Best and Latest in Computer Technology...

Look to Howard W. Sams & Co., Inc.

There's something for everyone—from those who want to discover what com-puters are all about to those who are already utilizing computers and program-ming. The fundamentals . . . programming . . . interfacing . . . logic—we are thecomplete knowledge source for home, business, educational and professionalusers.

('ompiiK'i'pictfonarv

ftii\ni>iv-vk

"Reference"Library

□ Computer Dictionary &Handbook (3rd Ed.)by Sippl and Sippl.The best and latest resource for anyoneinvolved in computers or computer ap-plications, over 900 pages; No. 21632$25.95

The "Starters"

□ The Howard W. Sams CrashCourse in Microcomputers

by Frenzel.Introducing ... the fastest and most ef-fective way for everyone from the aver-age consumer to the doctor of science tolearn about today's microcomputers.Focuses on all aspects of microcomput-ers from fundamentals and operatingsystems to programming and modernperipheral equipment such as floppydisks. 264 pages. No. 21634. $17.50

□ How To Buy & Use Minicomputersand Microcomputersby Barden.

A single source to buying and using a computer in your homeor business to handle recreational or practical tasks fromplaying games to setting up a burglar alarm. 240 pages, No.21351. $9.95

□ Getting Acquainted With Microcomputersby Frenzel.Gives you a complete working knowledge of the microcom-puter-organization, operation, and programming. 288 pages,No. 21486, $8.95

□ Fundamentals of Digital Computers (2nd Ed.)by Spencer.Unravels the mysteries of computers and programming. 320pages, No. 21534, $9.95

□ Introduction to Microcomputers for llflifPlthe Ham Shack

by Helms.Gives the radio amateur an opportunity to be in the forefrontof utilizing and developing techniques in "computercations."96 pages, No. 21681, $4.95

Prepub Offer—Save 10% (expires8/30/80)

□ Microcomputer Primer,(2nd Ed.)

by Waite and Pardee.Completely revised and broadened to reflect thelatest advances in microprocessor technology fromthe new 8-bit microprocessors to solderless bread-boards. An excellent starting point for all thoseinterested in computers. Approximately 368 pages,No. 21653. Prepub price—$10.76. RegularPrice—$11.95

The "Programmers"

□ 5

How to Program Microcomputers

Barden.

A popular, complete guide to assemblylanguage programming of the Intel8080, Motorola MC6800, and MOSTechnology MCS 6502 Microprocessors.256 pages. No. 21459, $8.95

□ BASIC ProgrammingPrimer

by Waite and Pardee.Covers everything from getting or-ganized to writing a game program. 240pages, No. 21586, $8.95

□ DBUG: An 8060 Interpretive Debugger fj Iby Titus and Titus. JLJ™

Covers program operation and how it's applied to programdevelopment and testing. 112 pages, No. 21536, $4.95

□ 6502 Software Designby Scanlon.

Tells how to program for the 6502 assembly language. Ap-proximately 288 pages, No 21656, $9.95*

11

□ 8080/8085 Software Design,2 volumes

by Titus. Larsen. & TitusVolume 1 gives you an introduction to assembly languageprogramming. 336 pages, No. 21541, $9.50—Volume 2 is aunique, one-of-a-kind, computer science book for the designengineer. Written in Intel machine code. 352 pages, No.21615. $9.95Two-volume set No. 21659, $17.50

□ TEA: An 8080/8085 Co-ResidentEditor-Assembler

by Titus.256 pages. No. 21628, !

1.95

U

The "Computer Technology"Leaders

frgtOO □

microcomputer

hondbook

The Z-80 MicrocomputerHandbook

by Barden.Gives current and prospective users aone-stop source to Z-80 technology—hardware and software aspects and in-strumentation problems. 304 pages, No.21500, $8.95

L fiTM :' I I—I Using the 6800I #fc....;V v" ' I Microprocessor

by Poe.

Acquaints you with the hardware and software of the "6800"fun machine. 176 pages; No. 21512, $6.95

□ Computer Graphics Primer IflPIIIIII

by Waite. Ill IIH&WH

Shows how to create your own graphic affects—from de-tailed drawings to moving figure animation. 184 pages, No.21650. $12.95

□ Microcomputers for Business Applicationsby Barden.Explains the various types of microcomputers available,points out pitfalls to avoid, and defines computer-relatedterms, or "buzzwords" in easy-to-understand language. 256pages, No. 21583, $8.95.

"Interfacing" Bookshelf

□

S^

Microcomputer-Analog ft IConverter Software & XJ™Hardware Interfacing

by Titus, Titus, Rony, and Larsen.Concepts and techniques of interfacingdigital computers to analog devices.288 pages, No. 21540; S9.50

□ TRS-80 Interfacingby Titus.192 pages; No. 21633; $8.95

JU.

JU.

□ Interfacing & Scientific DataCommunications Experiments

by Rony, Larsen. Titus, & Titus. [J i160 pages. No. 21546. $5.95 ■*■*

□ Microcomputer Interfacing With the8255 PPI Chip

by Goldsbrough.224 pages. No. 21614. $8.95

□ Z-80 Microprocessor Programming& Interfacing, 2 Volumesby Nichols. Nichols. & Rony. ft J800 pages. No. 21611, $21.95. XJ™

□ Introductory Experiments in Digital ftElectronics and 8080A Microcomputer JLProgramming and Interfacing, 2 Volumes,

by Rony. Larsen. and Titus.912 pages; No. 21552; $20.95

□ Computer Dictionary (3rd Edition)by Sippl and Sippl.Over 12,000 entries, 640 pages, No. 21652. $11.95*

"Logic" Cookbooks

1 1 Lancaster's Cookbook Library

A famous resource for all electronic buffs who wantto know what makes TTLs. CMOS, and active filterscook—what they are, how they work, and how touse them.

by Don Lancaster, one of the mosin the electronics industry.

popular

authors

TTL Cookbook 21035

$ 9.50

CMOS Cookbook 21398

10.50

Active-Filter Cookbook 21168

14.95

TOTAL LIST PRICE

$34.95

Less 15% Discount

5.24

You Pay Only

$29.71

Order Special Library Package No.

21707 and SAVE!

□ The Cheap Video Cookbookby Lancaster.256 pages, No. 21524, $5.95

□ IC Op-Amp Cookbookby Jung. 592 pages. No. 20969, $12.95

CU

IC Converter Cookbook

Jung. 576 pages. No. 21527. $13.95

"Tentative price

Look to Sams . . .In the world of computers

ORDER FORM

HOWARD W. SAMS & CO., INC.

4300 WEST62ND STREET, P.O. BOX 7092

INDIANAPOLIS. INDIANA 46206

(317)298-5400

Indicate quantity in boxes above and complete ordering in-formation below;

Sub Total

Add local sales tax where applicable

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Prices subject to change without notice. All books available Ifom SamsDistributors, Bookstores, and Computer Stores. Offer good in U.S. only.Note: Distributor, computer store and dealer inquiries are welcome.

Circle 149 on inquiry card.

BYTE May 1980 237

Event Cueue

MAY 1980

May and June

Microprocessor TrainingCourses, Cudham Hall,Cudham, Sevenoaks, Kent,ENGLAND. Microprocessorfamiliarization, micropro-cessor applications for theequipment user and for themanufacturer, andmicroprocessor-based equip-

ment design and develop-ment are the courses beingoffered by the Sira InstituteLimited. Write to Con-ference and Courses Unit,Sira Institute Ltd, SouthHill, Chislehurst, KentBR7 5EH ENGLAND.

May 1-2Programming LanguageTechnology and Ada, San

Francisco CA. Conductedby Anthony Wasserman, the

conference will discuss con-cepts of programminglanguages including thosewhich support Ada languagedefinition and developmentactivity. The course costs$450. Registration informa-tion is available from Soft-ware Research Associates,POB 2432, San FranciscoCA 94126.

May 5-7

Software Principles forManagement, San FranciscoCA. The course is intendedfor managers who need tounderstand what software isand how to utilize it proper-ly. Registration is $675, and

INTELLIGENT

W31

Eliminate The Data Comm Hassles ofOutmoded "DUMB" Modems

BIZCOMP's Intelligent Modem is new. Brand new. It teams a Bell 103-type "dumb"modem with a custom BIZ-080 microcomputer in an attractive desk-top enclosure.RESULT: Incredibly simple data comm for professional users. No more mad dashto get a handset into coupler muffs before being disconnected by the remote. Nomore exclusion-key telephone needed to do the dialing. No more outboard couplerboxes. And for computer sites, communications software written in high levellanguage like BASIC or COBOL. How's that for simplicity!

The 1030 gives you automatic dial, automatic answer and, unique to the industry,automatic REPEAT dial. The top-of-the-line 1031 adds command-selectable tone ordial pulse dialing for TWX net applications and self-test for ensuring full function-ality. Both models are FCC registered for direct connection and feature commrates from 110, 134.5, 150, 200 to 300 baud. BIZCOMP's innovative Code-Multi-plexed Design enables complete control using a simple 3-wire RS-232 interface.Don't burden your customers with data comm hassles. Install a BIZCOMP Intelli-gent Modem today.

BIZCOMP Communications...

Why not start with the best?

P.O. Box 7498 • Menlo Park CA 94025 • 415/854-5434

Suggested prices from $395.00

Patent Pending

additional information isavailable from TechnologyTransfer Institute, POB49765, Los Angeles CA90049.

May 5-7

Data Communications,

George Washington Univer-sity Library, 2130 H St. NW,Washington DC. This courseis intended to highlight ma-jor data communication ser-vices available, the basicchoices in designing a datacommunications network,and essential engineeringaspects of data communica-tions. It is intended forsystems analysts, engineersand managers. Contact theDirector, ContinuingEngineering Education,George Washington Univer-sity, Washington DC 20052.The course fee is $510.

May 6-10The Eighth Annual Cana-dian Association for Infor-mation Science, Toronto,CANADA. Technology,commodity, and rights arethe themes of this con-ference. Topics will coverinformation in themarketplace, informationtransfer and policy issues,right to access, new infor-mation technologies andapplications, and other sub-jects. For more information,contact the Program Chair-man, Eighth Annual CAISConference, Technical Infor-mation Centre, BellNorthern SoftwareResearch, 12th Floor, 522University Ave, Toronto,Ontario M5G 1W7CANADA.

In order to gain optimalcoverage of your organi-zation's computer con-ferences, seminars, work-shops, courses, etc, noticeshould reach our office atleast three months in advanceof the date of the event.Entries should be sent to:Event Queue, BYTE Publica-tions, 70 Main St, Peter-borough NH 03458. Eachmonth we publish the currentcontents of the queue for themonth of the cover date andthe two following calendarmonths. Thus a given eventmay appear as many as threetimes in this section if it issent to us far enough inadvance.

238 May 1980 © BYTE Publications Inc

Circle 150 on inquiry card.

we have the largest selectionof TRS-80*, APPLE* andATARI* software, anywhere!

TRS-80*

Acctt fl« II Disk 32K 89.95

Adv Psrs Fin Disk 24.95

Adventure Simple = 0 5.95

2 Adventures on Disk 24.95

D Lind S Pirate

D Mission 8 VoodooD Count S OdysseyD Fun House & Pyramid

3 Adventures Disk 39.95

□ Land Pirate Mission

□ Count Voodoo Odyssey

Adventures on tape 14.95

D CountD Fun House

□ Land

G Mission Impossible

D Pirate's Cove

D Pyramid ol Doom

G Strange Odyssey

D Voodoo

Adventure |Mlcrosoll] 29.95

Air Bald 9.95

Allen Invasion [soundl cass. 9.95

Allen Invasion jsound] disk 14.95

Amateur Hadlo Disk 24.95

Amazln' Mazes 7.95

Android Mm |sound| 14.95

APL disk 34.95

APL w/book 49.95* S3

APL tape 14.95

APL book only 15.50* S3

Appointment Log 9.95

Automated Disk Directory 14.95

Barricade 9.95

Basic Handbook 14.95*81

Basic Statistics 9.95

Basic Styles Handbook 5.95 * SI

Bee Wary {sound] 14.95

Binders 4.95* SI

Blorilylhml 4.95

Bridge Challenger 14.95

Cassettes

DC-ID 10 lor 6.50* SI

GC-20 10 lor 7.50* SI

Casino Anthology 7.95

Challenge Isoundl 9.95

Chess Companion 7.95

COMPBOC Command Processor

tape lor disk only SI 9.95

Crlbbage 7.96

Dala Management System |CCA| ... 79.95 * S2Diskettes

BASF D 5 lor 24.95*81

a 10 lor 39.95* 81

D 20 lor 69.95 * $2

D 100 lor 299.00 * S3

Dyian box ol 5 29.95 ♦ SI

Dynamic Data Base 39.95

Diskette Storage Box 5.00 * 81

Oosorl 32K or 48 laps 34.95

DSM Sort Utility lor disk 75.00

Editor/Assembler Plus I6K tape 29.95

Electric Pencil tape 100.00

Electric Pencil disk 150.00

Circle 151 on inquiry card.

Educator Assistant 9.95

B080-ZBO Conversion 14.95

Electronics Assistant 9.95

End Zone II 9.95

Fastgammon 19.95

File Manager BO 49.96

Floppy Armour.... box "M 5 4.95 * SI

Floppy Disk Diagnostic 24.95

Fortran/Assembler.. .150.00*85

Fortrsn 80.00 * 82.50

Assembler ,. 80.00 * S2.50

Galactic Empire . . 14.95

Galactic Trader . . 14.95

Galactic Empire/Trader

disk 29.95

GSF I6K.32K.48K

24.95

Ham Radio

9.95

Ham Radio

Advanced Version 32K

disk 24.95

Hlstograph/Scatlerp/arn ... 9.95

Home Financial Management 9.95

I Chlnfl Level II I6K 7.95

Infinite BASIC by Racel 49.95

Business add-on 29.95

Intro TRS-BO Graphics 7.95 + SI

Inventory 11.3 Disk 79.95

Inventory S tapB 24.95

Inventory S disk w/lnvolclng 59.95

w/o/involclng 39.95

Journey Center Earth 7.95

Kamikaze 7.95

Keyboard 9.95

Krlegspell 7.95

KVP 24.95

KVPon Disk 29.95

KVP 232 24.95

Learning Level II 15.95 * SI

Level I in Level II 14.95

Level III BASIC 49.95

Life Two |sound| 14.95

Loan Amortization 19.95

Lost Dutchman's Gold 9.95

Machine Lang Mon. |RSV.2| 26.95

Machine Lang Mon. |RSV.2D| 29.95

Magic Paper Calculator 14.95

Mall List II Disk 99.95

Mastermind 7.95

Mastermind II 14.95

Mean Checkers Machine tape 819.95

Mean Checkers Machine disk 24.95

Mlcrochess 1.5 19.95

Mlcrosoll Edltor/AssemblBr Plus 29.95

Micro Tax I lape 25.00 * S2

Micro Tax II lape 35.00* S2

Micro Tax III lape 50.00 * 82

Mlcrotext Editor 9.95

Mortgage Calculalor 3.95

Moving Signboard 9.95

NEWOOS 49.95

NEWDOS* 99.95

NEWOOS BO 149.95

9 Games/Preschool Child 9.95

Numerology 32K disk 14.95

On Line Invoicing disk 39.95

Pathways Through the ROM 19.95

Payroll Olsk 32K 39.95

Pencil Pal 35.00

Pentomlnoes fsound] 7.95

Periodical Cross Reference lape 14.95

Periodical Cross Relerence disk 19.95

Personal Finance 9.95

Pigskin 9.95

Pork Barrel 9.95

PR Dogllghl 7.95

Prelllghl 20.00

Print Spooler disk 24.95

Remodel « Proload I6K.32K.4BK . . 34.95

Renumber 7.95

Renumx 24.96

Roots disk 19.95

RPN Calculator 9.95

RSM-2 26.95

RSM-20 29.95

RX |dlsk| 24.95

Sargon Chess 19.95

Sargon II 29.95

Sargon Handbook 15.95 * 81

Secrets ol the Tarol 9.95

Small Business Bookkeeping tape 24.95

Small Business Bookkeeping disk 29.95

Small Business Bookkeeping lournal 7.00

Snake Eggs Isounil) 14.95

Space Battles tape 14.95

Space Battles disk 19.95

STAD 24.95

Star Trek 111.4 14.95

ST80 Smart Terminal 49.95

ST80D Smarter Olsk 79.95

STBOIII 150.00

STBOUC 24.95

Super Simon 89.95

System Copy 9.95

T Short 9.95

Talpan 9.95

Tape Recorder Alignment Kit 9.95

Text BO Disk 59.95

Time Series Analysis 14.95

Time Trek 14.95

Ting Tong Level II I6K 9.95

Tiny Comp lape 19.95

Tiny Comp disk 24.95

Troll's Gold 4.95

TRS-80 Assy. Lan. Pro 3.95+ SI

TRS-80 Olsk 8 Olher Mysteries .... 22.95 * SI

TRS-80 Interlacing 8.95* SI

TRS-80 Opera Theatre (sound) 9.95

with challenge on disk 19.95

Tycoon 7.95

Typing Tutor 19.95

VTOS 11 49.95

VTOS 3.1 manual 29.95* S3

VTOS II w/manual 74.95 * S3

VTOS 3.1 w/BASIC 99.95 * S3

Warlare 7.95

Wordo 14.95

X-WIng Fighler II 9.95

XREF 19.95

Y-Y Bar by Racel 14.95

Z 80 Chip Poster 3.99* SI

Z 80 Gourmet Cookbook 14.95 * SI

Z-80 Handbook 4.95* SI

Z SO and BOBO Assembly 7.95* SI

APPLE

Adventure Sampler .V / cass. 5.95

Allen Invasion cass. 9.95

Android Nim disk 17.95

Appen I Text Editor cass. 17.95

Appilot Edu-Olsk disk 49.95

Apple 21 cass. 9.95

Apple Invader cass. 15.95

disk 19.95

Applellstner cass. 15.95

ApplBlalkBr cass. 15.95

Baseball cass. 14.95

BASIC Handbook 14.95+ SI

Blitzkrieg cass. 15.95

Breaklhru cass. 9.95

Bridge Challenger cass. 14.95

CCA Dala Base Manager disk 99.50

IWorks in con|unctlon with Vlsicalc]

Count Adventure cass. 14.95

Dan's Disk Utilities disk 39.95

Or Memory disk 49.95

Dungeon Campaign cass. 12.50

disk 14.95

Electric Crayon cass. 17.95

Engineering Math Tape 1 cass. 14.95

Escape cass. 12.95

Fastgammon cass. 19.95

Form Letter disk 24.95

Forte cass. 19.96

Fun House Adventure cass. 14.95

Game Playing Tape 1 cass. 995

Gamo Playing Tape 2 cass. 9.95

GamB Playing Tape 3 cass. 9.95

General Math Tape I cass. 14.95

Global War disk 24.95

Hl-fies Boxing cass. 15.95

Higher Graphics disk 24.95

Land Adventure cass. 14.95

Little Book ol BASIC Style 5.95 + SI

Mailing List disk 39.95

Mailing Ust Database disk 34.56

Master Catalog disk 29.95

Maze Game cass. 12.95

Memo Calendar disk 29.95

Micro Information System disk 99.95

Mission Impossible Adventure — cass. 14.96

Music Box cass. 12.95

Pirates Cove Adventure cass. 14.95

Pyramid ol Doom Adventure cass. 14.95

Sargon cass. 19.95

Sargon II cass. 29.95

Side Shows cass. 12.95

Strange Odyssey Adventure cass. 14.95

Stunt Cycle cass. 15.95

Super-Text disk 99.95

Tank War cass. 12.95

Texl Editor disk 64.95

Three Mile Island disk 39.95

U-Drawl cass. 17.95

U-Orow II disk 39.95

Uncle Sam's Jigsaw cass. 12.95

Vlsicalc disk 150.00

Voodoo Castle Adventure cass. 14.95

Wilderness Campaign cass. 14.95

disk 17.50

Wilderness 8 Dungeon Campaigns.. disk 29.95

A

ATARI

o

A Warner Communications Company

ROM CARTRIDGES

Assembler/Editor 59.95

Besketball 39.95

Video Easel 39.95

Super Breakout 39.95

Music Composer 59.95

Computor Chess 39.95

3D Tic-Tac-Toe 39.95

Slar Raiders 59.96

Personal Finance 59.95

EDUCATION SYSTEM CASSETTE PROGRAMS

U.S. History 29.95

U.S. Government 29.95

Supervisory Skills 29.95

World History (Western] 29.95

Basic Sociology 29.95

Counseling Procedures 29.95

Principles ol Accounting 29.95

Physics 29.95

Great Classics 29.95

Business Communications 29.95

Basic Psychology 29.95

EllBdive Writing 29.95

Principles of Economics 29.95

Spelling 29.95

Basic Electricity 29.96

Basic Algebra 29.95

BASIC PROGRAM CASSETTES

Introduction to Programming 19.95

Kingdom 14.95

Lemonade 14.95

Baseball 14.95

Blackjack 14.95

Mugwump 14.95

Biorhythm 14.95

Hangman 14.95

The Software Exchange

6 South Street, Box 68, Milford, NH 03055 603-673-5144

TO ORDER CALL TOLL-FREE

I ■OU0"258" 1 790 (III NH call 673 5144)

*TRS-80 is a trademark of Tandy Corporation

'Apple is a registered trademark of Apple Computer Co.

*Atari is a registered trademark of Warner Communications.

BYTE May 1980 239

May 12-13

Data Communications,

Worcester Polytechnic In-stitute, Worcester MA. Thisseminar is designed to helpprofessionals develop an ef-fective data communicationssystem. Network design, re-quirements, software,diagnostics, and controls aresome of the issues to becovered. The fee is $375which covers everything ex-cept hotels. For information,contact Office of ContinuingEducation, WorcesterPolytechnic Institute,Worcester MA 01609.

May 13-15

Microprocessors: New

Directions for Mankind,

Albuquerque NM. Thissymposium will deal with avariety of microprocessorapplications. It is part of theIdeas in Science and Elec-tronics Show. Contact JArlin Cooper, Div 2331,Sandia Laboratories, Albu-querque NM 87185.

May 13-15

Electro/80 Show and Con-vention, Hynes Auditoriumand Boston Sheraton,Boston MA. This show con-sists of presentations andexhibitions by computer in-dustry manufacturers. Con-tact Electronic Conventions

Inc, 99 N Sepulveda Blvd,El Segundo CA 90245.

May 13-16

The Ninth Annual Con-ference of MUMPS UsersGroup, Islandia HyattHouse, San Diego CA. Thismeeting will bring togetherscientific, medical, andbusiness professionals todiscuss current research andapplication development.Areas of participation arepaper presentations,workshops and tutorials,and vendor exhibits. Con-tact Dr Jack Bowie, MUG 80Program Chairman, TheMitre Corp, Mail Stop 641,

D

ESK

TO

P

GOMPUTER

Chrislin is First!!!

with deliveries of DEC'S Desk Top Computers. Available withLSI 11/2 or LSI 11/23 CPU. Complete system totally enclosedwithin VT100 Video Terminal. Price $4,500 with LSI 11/2 and64K bytes or $8,995 with LSI 11/23 and 256K bytes.

NOW Available — PDP 11/23 with 256 KB Memory $8,900.

SPECIAL — LSI 11/2 and 32K x 16 Memory $1,095.

10 MEGA BYTE Cartridge Disk System with Controller, RT11compatible $6,100.

1 MEGA BYTE RX02 Floppy Disc System $3045.

€

Chrislin Industries, Inc.

, Computer Products Division

31352 Via Colinas • Westlake Village, CA 91361 • 213-991-2254

1820 Dolley Madison Blvd,McLean VA 22102.

May 21-22

The Second Clemson SmallComputer Conference,

Clemson University, Clem-son SC. This program willconsist of presentations,discussions and an exhibi-tion. Emphasis will be placedon business, industry,engineering, science, andeducation. For registrationinformation, contact J KJohnson, ContinuingEngineering Education,Clemson University, Clem-son SC 29631. For generalinformation, contact W JBarnett, Electrical and Com-puter Engineering Dept,Clemson University, Clem-son SC 29631.

May 21-23

Business and Personal Com-puter Sales-Expo 80,

Philadelphia Civic Center,Philadelphia PA. This showis aimed at a wide range ofinterests in business and anyother area that has a needfor computers andcomputer-related products.Exhibitors will be givingdemonstrations of equip-ment. Contact Produx 2000Inc, Roosevelt Blvd andMascher St, Philadelphia PA19120.

May 23

The Digital ComputerAssociation, AnnualMeeting, Pacifica Hotel,6161 Centinela Blvd, CulverCity CA. A slide show,followed by dinner and anevening program, are themain events of the meeting.The price is $15 prepaid.Send reservations to MaryRich, 731 Bayonne St, ElSegundo CA 90245.

May 24-25Amateur Radio and Com-puter Hobbyists Second An-nual Convention, CervantesConvention Center, St LouisMO. Speakers, presenta-tions, equipment displays,and a flea market will befeatured. For more informa-tion, contact the GatewayAmateur Radio AssocationInc, POB 68, Marissa IL62257.

240 May 1980 © BYTE Publications Inc

Circle 152 on inquiry card.

Circle 153 on inquiry card.

DYNACOMP

Quality software for:

Apple II PlusTRS-80 (Level II)North Star

All software is supplied with complete documentation which includes clearexplanations and examples. Each program will run with standard terminals (32characters or wider) and within 16K program memory space. Except wherenoted, all software is available on North Star diskette (North Star BASIC),TRS-80 cassette (Level II) and Apple cassette (Applesoft BASIC). These pro-grams are also available on PAPER TAPE (Microsoft BASIC).

Price: $17.95 postpaid

FLIGHT SIMULATOR

(as described in SIMULATION, Volume II)

A realistic and extensive mathematical simulation of take-off, flight and landing. Theprogram utilizes aerodynamic equations and the characteristics of a real airfoil. Youcan practice instrument approaches and navigation using radials and compassheadings. The more advanced flyer can also perform loops, half-rolls and similaraerobatic maneuvers.

SIMULATION, Volume II (BYTE Publications): $6.00

V ALDEZ Price: $14.95 postpaid

A simulation of supertanker navigation in the Prince William Sound and ValdezNarrows. The program uses an extensive 256X256 element radar map and employsphysical models of ship response and tidal patterns. Chart your own course throughship and iceberg traffic. Any standard terminal may be used for display.

BRIDGE 2.0 Price: $17.95 postpaid

An all-inclusive version of this most popular of card games. This program both BIDSand PLAYS either contract or duplicate bridge. Depending on the contract, your com-puter opponents will either play the offense OR defense. If you bid too high the com-puter will double your contract! BRIDGE 2.0 provides challenging entertainment foradvanced players and is an excellent learning tool for the bridge novice.

HEARTS 1.5 Price: $14.95 postpaid

An exciting and entertaining computer version of this popular card game. Hearts is atrick-oriented game in which the purpose is not to take any hearts or the queen ofspades. Play against two computer opponents who are armed with hard-to-beat play-ing strategies.

DATA SMOOTHER Price: $14.95 postpaid

This special data smoothing program may be used to rapidly derive useful informationfrom noisy business and engineering data which are equally spaced. The softwarefeatures choice in degree and range of fit, as well as smoothed first and secondderivative calculation. Also included is automatic plotting of the input data andsmoothed results.

FOURIER ANALYZER Price: $14.95 postpaid

Use this program to examine the frequency spectra of limited duration signals. Theprogram features automatic scaling and plotting of the input data and results. Prac-tical applications include the analysis of complicated patterns in such fields as elec-tronics, communications and business.

MAIL LIST I Price: $18.95 postpaid (available for North Star only)

A many-featured mailing list program which searches through your customer list byuser-defined product code, customer name or Zip Code. Entries to the list can be con-veniently added or deleted and the printout format allows the use of standard sizeaddress labels. Each diskette can store more than 1000 entries.

MAIL LIST SERVICE

DYNACOMP can provide you with a customized mail list service. Your customer/patient records are placed in a master computer file and you are provided with address-ed, self-adhesive labels for your mailings. These labels may be sorted by name. ZipCode, date, or other identifiers. Write for further details and a price schedule.

TEXT EDITOR I (Letter Writer) Price: $14.95 postpaid

An easy to use, line-oriented text editor which provides variable line widths and simpleparagraph indexing. This text editor is ideally suited for composing letters and is quitecapable of handling much larger jobs.

GAMES PACK I Price: $10.95 postpaid

Seven entertaining games for less than a dollar a kilobyte! Play CATAPULT, CRAPS,SWITCH, HORSERACE, SLOT MACHINE, BLACKJACK and LUNARLANDER. This is an excellent and economical way to start your games library.

All orders are processed within 48 hours, Please enclose payment with order. If paying byMASTER CHARGE or VISA, include all numbers on card. Foreign orders add 10% for

shipping and handling.

Write for detailed descriptions of these and other programs available from DYNACOMP.

DYNACOMP

P.O. Box 162

Webster, New York, 14580

New York State residents please add 7% NYS sales tax.

PRINTED CIRCUIT KIT

Makes circuits THREE WAYS

1 FULL SCALE ARTWORK MASTER |

*^B- DEVELOPED

2 MAGAZINE ART ^ FILM ^ Z. -k. PHOTORESIST _k. ETCHED

ILLUSTRATION |V POSITIVE ^P NEGATIVE M IMAGE ON ,^fc CIRCUIT

^T ^^ ^ COPPER CLAD ^W BOARD

CIRCUIT BOARD

^ DIRECT ETCH DRV TRANSFERS APPLIED TO COPPER CLAD BOARD I

Copy circuits right from a magazine using special photo filmNo camera or darkroom used. Page is not destroyed in process.

Do your own master art, make negatives, sensitize boards andetch one or a hundred circuits; all identical, all perfect.

For one-of-a-kind PC's, use special dry transfer patterns asa direct etch resist right on the blank copper board.

Do it all with the ER-4. In stock at parts distributors or orderdirect. Add 7% shipping. Minimum factory order: $30.00.

ER-4 Complete Photo Etch Set $29.95

ER-2 Assorted Etch Resist Patterns & Tapes 4.25

ER-3 1/4 lb. Dry Ferric Chloride (makes one pint) .... 1.95

ER-5 Six sheets Pos-Neg Copy Film, 5"x6" 5.15

ER-6 Film Process Chemicals 2.50

ER-71 Photo Resist Liquid (negative) does 1700 in2.... 6.50

ER-8 Photo Resist Developer, 16 oz 3.30

ER-12 Power Etch bubble pump unit* 7.25

*not included in ER-4 set

the DATAK corp.65 71st St. • Guttenberg, N. J. 07093

8" DISK CONTROLLER

NOW—DOUBLE SIDED OPTION!

• DOUBLES APPLE ][ STORAGE

• APPLE DOS COMPATIBLE

• SHUGART 800 OR 850 COMPATIBLE

• IBM 3740 DATA ENTRY CAPABILITY

• CP/M, UCSD PASCAL CAPABILITYAvailable at your local APPLE Dealer: $400.

£SVA>

SORRENTO VALLEY ASSOCIATES

11722 SORRENTO VALLEY RD.SAN DIEGO, CA 92121

Circle 155 on inquiry card.

Circle 154 on inquiry card.

BYTE May 1980 241

May 31

Amateur Radio Fair, Min-nesota State Fairgrounds, StPaul MN. The North AreaRepeater Association issponsoring this swapfest andexposition for personal com-puter enthusiasts and radioamateurs. There will be freeovernight parking for self-contained campers on May30. The admission is $3. Forinformation, write AmateurFair, POB 30054, St PaulMN 55175.

May 31-]une 1

Microcomputers and thePhysician's Office, HyattRegency Hotel, San Fran-cisco CA. This seminar willprovide a realistic look atmicrocomputer applicationsin the private practice. Con-tact Medical Data Systems,POB 193, Ojai CA 93023.

JUNE 1980

June 2-4Improving Productivity andDistributed Data Entry,

Sheraton Center, New YorkNY. The conference andseminar schedule includesdiscussions on word process-ing, data processing, futuredirections of data entry, im-proving data entry produc-tivity, automated offices, in-stalling a data-entry incen-tive system, and more. Con-tact Data Entry ManagementAssociation, POB 3231,Stamford CT 06905.

June 4-5

Microprocessors: Hardware,Software, and Application,

Holiday Inn, Boston MA.This course is recommendedfor technical professionalswho need an understandingof microprocessors in rela-tion to their corporate andbusiness careers. ContactOffice of Continuing Educa-tion, Worcester PolytechnicInstitute, Worcester MA01609.

June 4-6

Salon de l'Ordinateur Com-puter Show, Place Bonaven-ture, Montreal, CANADA.This exhibition will feature

over eighty manufacturers'hardware and software.For more information,contact Industrial TradeShows of Canada, 36 But-terick St, Toronto, OntarioM8W 3Z8 CANADA.

June 9-13

Microcomputer Workshop,

Carnegie-Mellon University,Pittsburgh PA. Engineers,research scientists,educators, and managerswill benefit from this course.It covers all aspects ofmicrocomputers and soft-ware. Hands-on-training willbe provided. The tuition is$585 and housing can be ar-ranged. Contact the PostCollege Professional Educa-tion, Carnegie-MellonUniversity, Pittsburgh PA15213.

June 14Microcomputers in Businessand The Professions:Systems Selection, ButlerUniversity, 4600 N SunsetAve, Indianapolis IN. Thisseminar will cover varioustypes of hardware and soft-

ware, how to evaluate thekinds and performances ofcomputers, and their ap-plications in business andhome use. The registrationfee is $75. For information,contact College of BusinessAdministration, ButlerUniversity, 4600 N SunsetAve, Indianapolis IN 46208.

June 15-18

International Summer Con-sumer Electronics Show,

McCormick Place, McCor-mick Inn, Pick-CongressHotel, Chicago IL. The Con-sumer Electronics Show(CES) will feature exhibitsfrom many companies;seminars and discussions;and items ranging fromtelevisions, tape recorders,telephones, and translators,to computers, componentsystems, auto soundsystems, and electronicgames will be displayed. At-tendance is limited to dealersand the press. Contact Con-sumer Electronics Shows,Two Illinois Center, Suite1607, 233 N Michigan Ave,Chicago II 60601.

~mmmmm*-..

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o

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64K 1 Drive$3499.00

Popular 16K Level 11 System S 722.00

26-1145 RS-232 Board 84.00

26-1140 "O" K Interface 254.00

26-1160 Mini Disk 424.00

26-1171 Telephone Modem 169.00

Fas! 100 CPS Centronics 730 Printer 750.00

Highly Reliable Lobo 5 V Drivts 375.00

Versatile Lobo Interface, 8" Drives

and IMI Hard Drives Call For Prices

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No Taxes on Out OfState Shipments

Immediate ShipmentFrom Stock.

MICRO MANAGEMENT SYSTEMS, INC.

DOWNTOWN PLAZA SHOPPING CENTER

115CSECONDAVE.S.W.

CAIRO, GEORGIA31728

912-377-7120

Full Factory Warrantyon All Items Sold.

VISA, Master Chargeand COD's, Add 3 %

242 May 1980 © BYTE Publications Inc

Circle 156 on inquiry card.

Circle 157 on inquiry card.

0j LIGHT PEN

PET

APPLE

TRS-80

(Level II)

I Bypass the keyboard and interact directly with the screenMakes your computer more versatile for the novice as wellas the more sophisticated user

I The use of the 3-G Light Pen is limited only by your Im-agination! Use it to experiment with graphics, display amenu for quick data retrieval, as a teaching tool with yourchild, to proportion recipes instantly, or to play uniquegames.

I At a maior medical center an anesthesiologist uses our pen to select proper dosages. In Hollandthey use it to create graphics. A man in New York uses it to teach his pre-school age daughter howto match capital with lower case letters. Teachers are using it in science and foreign languageclasses.

I NO ASSEMBLY NECESSARY. READY TO PLUG IN. Detailed sample programs included. Completedocumentation so you can write your own programs in BASIC. No machine language coding nec-essary All Professional models plug into machine ports and don't require batteries Economymodel plugs into tape recorder and batteries are included

I YOU GET: l) 3-G Light Pen

2) Demo-Game Cassette (with Professional TRS-80, PET and Apple)

3) Sample Program.

4) Complete documentation and instructions.

MANY GAMES AND OTHER LIGHT PEN SOFTWARE AVAILABLE.

MAIL COUPON OR CALL TODAY FOR IMMEDIATE DELIVERY

3G COMPANY, INC. DEPT. BT (503) 662-4492

RT. 3, BOX 28A, GASTON, OR 97119

Q

TRS-80 EconomyS19.95

TRS-80 Professorial$34.95

PET ProfessionalS3 1.95

Yes, I warn to make my computer more versatile Rush me

$1 50 lor mailing and handling - $6.00 foreign )

Enclosed is check or money order I Master Charge Visa

Card NoNAME

Apple Professional$32.95. 3-G Light Pens (Add

Exp date

ADDRESS.City

REMEMBER, 3G OFFERS A 30 DAYUNCONDITIONAL MONEY BACK GUARANTEE!

LRCEATON

MODEL 7000+IMPACT PRINTER

>oo+^

• Simple Design

• Simple Maintenance

• Simple Interfacing to

- Apple

- Pet

- TRS-80

- Exidy

- OSI

and many otherpersonal computers

The 7000+ was designed to provide the per-sonal computer user with an inexpensive, yetreliaPle printer. Take a look - you won't regret it!

• Impact Unidirectional

• 1.25 LPS; 50 CPS

• 40 or 64 Column

• 5 x 7 Dot Matrix

SPECIFICATIONS

• Standard Paper Rolls

• TOO Million Character PrinfheadLife (minimum)

• 6 LPI Line Spacing

Substantial Dealer Discounts are Available.

OEM inquiries are invited. Please contact:

SIGMA INTERNATIONAL, INC.

P.O. Box 1118 SCOTTSDALE, AZ 85252 USA

Tel. (602) 994-3435 Tlx. 165-745 Sigma Cable: SIGMAS

North

Star

Horizon

HeathH89

§Msl

CromemcoC3

TRS-80Model I

*v TRS-80Model II

■

YourComputer

"BSTAM"

Byrom Software Telecommunications Access Method

The missing link betweenany CP/M or TRSDOS computers!

A commercially oriented telecommunications

facility for transmitting and receiving

CP/M* and TRSDOS** files, BSTAM has BIG

computer features for your micro:

links computers directly at 9600 baud withUARTS, or via phone lines using modemsfull speed data transfer without hexconversion overhead

full wildcard expansions to send * .COM, etc.reliable error detectionand automatic retry withconsole messages forstatus and errors

It's Terrific!

We use it ourselves

sncnPER $r

IOU COMPUTER v.

PER $|- MANUAL

COMPUTER O ALONE

mmmm

*CP/M is a trademark of Digital Research' 'TRSDOS is a trademark of TandyCorporation

jpfeboat Associates

. THE

SOFTWARESUPER-MARKET

Lifeboat Associates

2248Broadway NewYork,N.Y.10024 (212)580-0082 Telex:220501

Circle 158 on inquiry card.

BYTE May 1980 243

June 16-20

Data Flow Concepts inComputer Language and Ar-chitecture, Massachusetts In-stitute of Technology (MIT),Cambridge MA. MIT's pro-gram will cover principles ofdata flow computerorganization and program-ming language design andapplications. Certain ar-chitectures will be coveredand techniques will bediscussed. Familiarity withlanguages and architecture isa prerequisite. The tuition is$750. Living arrangementscan be made through theschool. Contact the Officeof the Summer Session,Room E19-356, MIT, Cam-bridge MA 02139.

June 17-19

Data Comm, Palais des Ex-positions, Geneva,SWITZERLAND. Data com-munications and distributed-data processing are the mainthemes of this conferenceand exhibition. Softwaredevelopment and tools,computer languages, manag-ing data-communicationssystems, and definitions,

concepts, and applicationsof data communications anddistributed-data processingare some of the topics thatwill be covered in the con-ference.

For more information,contact Industrial and Scien-tific Conference Manage-ment Inc, 222 W Adams St,Suite 999, Chicago IL 60606.

June 18-21Association for Computa-tional Linguistics, Universityof Pennsylvania,Philadelphia PA. Themeeting will covertheoretical andmethodological problems ofcomputational linguistics,speech acts, analysis ofmultisentence texts,dialogue, machine transla-tion, and computationalsemantics. For further infor-mation contact Don Walker,Artificial Intelligence Center,SRI International, 333Ravenswood Ave, MenloPark CA 94025.

June 20-22The Fifth Annual Com-puterfest, Franklin Universi-

ty, Columbus OH. Spon-sored by the Midwest Af-filiation of Computer Clubs,this is a gathering of in-terested hobbyists, profes-sionals, and business-oriented computer users.Workshops and discussionsare the main features of theconference. Contact JamesCrowley, 4008 RickenbackerAve, Columbus OH 43213.

JULY 1980

July 7-11Computers and Related Pro-ducts, Hyatt Regency Hotel,Seoul, KOREA. This showis limited to approximatelyforty firms for exhibition.For details, contact RobertWallace, Rm 6015A, USDept of Commerce, Industryand Trade Commission,Washington DC 20230.

July 14-16Diagnostic Software: Plan-ning and Design, Sheraton-Lexington Motor Inn, Lex-ington MA. The seminar isfor design, test, and

diagnostic engineers. Designexamples, lectures, informalsessions, and programmingare part of the course. Thefee is $450. Contact Pro-fessor Donald French, In-stitute for Advanced Profes-sional Studies, One GatewayCenter, Newton MA 02158.

July 14-18

SIGGRAPH '80, SeattleCenter, Seattle WA. Paneldiscussions and readings willbe included in this con-ference. The topics will in-clude graphic displays,animation/dynamics, car-tography, input techniques,video and color hardware,and more. For general infor-mation, write to SIG-GRAPH '80, POB 88203,Seattle WA 98188.

July 22-24Microcomputer Show,

Wembley Center, London,ENGLAND. New productswill be exhibited, along withpresentations of papers. Forinformation contact TMAC,680 Beach St, Suite 428, SanFrancisco CA 94109. ■

LOW COSTCOLUMN IMPA

& SOPR INTER

MODEL 101A-40$ 295 KIT$325 ASSEMBLED & TESTED

MICROPROCESSOR CONTROLLED

IMPACT PRINTER5orlO X 7 DOT MATRIX96 ASCII UPPER'LOWER

CASE CHARACTERS

MODEL 101B-80$ 455 KIT$485 ASSEMBLED & TESTED

• PARALLEL & SERIAL INTERFACE

• 110 to 9600 BAUDRATE

• 110 CPS-ONE LINE PRINT RATE

• GRAPHICS MODE

CoosoL, Inc.P.O.Box 743A Anaheim. Ca. 92805

PHONE 7 D AY SA WEEK

(714) 545-2216

244 May 1980 © BYTE Publications Inc

Circle 159 on inquiry card.

Circle 160 on inquiry card.

PflSGDUMSOFTWARE

CP/M®

OSBORNE AND ASSOC.

business software in CBASIC-2

1 General Ledger

" Accl Rec./Accl. Pay. .' Payroll w/CosI Accl. .

Buy 2 eel I tree

All 3 plus CBASIC-2 .

5 /-

S59/S19each

S118/S57S199/S71

CBASIC-Z6 . . .

SB9/S14

TRS-80® MODEL II

CP/IVP 2.2Latest Version $149

ELECTRIC PENCIL II

Standard Printer $249

Diablo. Qume. NEC $279

APPLE I \®

VISICALC- by Personal Systems $122

DIGITAL RESEARCH

CP/M* 2.2 tor TRS-80" Model II S149/S24

CP/M" 2.2 lor Norlhstar $149/$24

WORDSTAR by MicroPro S399/S24

WHITESMITHS

•"C" Compiler $600/529

"Pascal (includes "C") $750/$44

■SELECTOR III-C2.

S269/S19

PEACHTREE business softwarein Microsoft BASIC source code.

t General Ledger

' Accl Rec

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1 Payroll [ each

' Inventory

All 5 plus WORDSTAR S1995/S349

VISA • MASTERCHARGEORDERS ONLY - CALL TOLL FREE1-800-854-2003 ext. 823 ACalif. 1-800-522-1500 ext 823a

For information write or call:

THE DISCOUNT SOFTWARE GROUP

1610 Argyle Ave., Bldg. 102

Los Angeles, CA 90028

(213)461-3127

CP/M users specily disk systems and formats

Mosi formats available

Ma $2 bO postage ana nananng per eacn item

California residents add b% sales tax

Allow 2 weeks on checks. C 0 0 ok

Prices subiect to change without notice

AH items suited to availaoiiily

P.S. — We want lo be your software source. Give us the opportunity to beat any nationally advertised price!

ED SMITH'S SOFTWARE WORKS6809 SOFTWARE TOOLS

RRMAC M6809 RELOCATABLE RECURSIVE MACROASSEMBLER. The

one assembler that contains real macro capabilities (see our May, JuneBYTE ad). RRMAC is designed with the assembly language programmerin mind and contains many programmer convenience features. RRMACcontains a mini-editor, supports spooling or co-resident assembly, allowsinsert files, is romable, generates cross-references, execution times, liststarget addresses of all relative references.

M69RR $150.00

SGEN M6809 DISASSEMBLER/SOURCE GENERATOR will producesource code (with symbolic labels) suitable for immediate re-assembly orre-editing. The output source file can be put on tape or disk. A fullassembly type output listing with labels and mnemonic instructions canbe printed or displayed on your terminal. Large object programs can besegmented into small source files. M69RS $ 50.00

ANNOUNCING TWO NEW M6809 DEVELOPMENT TOOLS

CROSSBAR-A 6809 TO 6800 CROSS MACROASSEMBLER that runs onyour M6809 development system to produce relocatable M6800 objectcode. Has all features of M69RR (see above). Includes 6800 LinkingLoader. M69CX $200.00

CROSSGEN-A 6800 OBJECT CODE DISASSEMBLER/SOURCEGENERATOR that runs on your M6809 development system. Has allfeatures of M69RS (see above). An invaluable tool for converting all 6800object files over to the M6809. M69CS $ 75.00

All programs are relocatable and come complete with Linking Loader,Programmer's Guide and extensively commented assembly listing.Available on 300 Baud cassette or mini-floppy disk. For disk, specify SSBor FLEX. Source Text input/output is TSC/SSB editor/assembler com-patable.

Order directly by check or MC/Visa. California residents add 6% sales tax.Customers outside of U.S. or Canada add $5 for air postage & handling.

Dealer inquiries welcome. FLEX is a trademark of TSC

Ed Smith's

SDFTWPIRE WDRHS

P.O. Box 339, Redondo Beach, CA 90277, (213) 373-3350

*5*° *

x>V

KRAM

Keyed Random Access Method

KRAM is the FASTEST and MOST POWERFUL keyed access methodavailable for the Appple Computer. Written entirely in 6502 machine code,KRAM is extremely fast, comprehensive in scope, very compact, and easyto use. KRAM function calls are invoked via a single instruction.

Using the sophisticated capabilities of KRAM the Apple Computer cannow fully meet the requirements of information managementapplications, such as: Accounts Receivable/Payable, Inventory Control,General Ledger, Payroll, and Database Management.

\«

«o

*&

$#•

9*

KRAM Release 2.0 Functions:

• Create/Open a dataset • Put record by Key

• Add & delete records by key

• Get any record by Full/Partial keyin 4/1 Oths of a second (2/1 Oths with Corvus Disk)

• Read next or previous record

• Dynamicspaceallocation

• Dynamic space reclamation

• Dynamic index compression

An 80 page manual fully documents KRAM 2.0 detailing KRAM functionsand illustrating with programming samples. KRAM architecture is fullyexplained and a sample mailing list application program is included.

KRAM is designed to work with both Apple's Disk 11, or Corvus Systems 10Megabyte Winchester Disk. KRAM 2.0 requires an integer Apple orApple Plus with integer card and at least one disk drive. Will not workwith language system.

PET/CBM OWNERS —KRAM 2.0for40/80 column

16K/32K PETS and 2040/3040/8050 disk units isavailable for $99.95

3-D AnimatedGraphics

APPLE

VvUKLLI ByPaulLutus

The Program made famous on National TV!

APPLE WORLD turns your Apple into a sophisticated graphics systemcapable of creating animated three-dimensional color images, projectingthem in true perspective on the screen, rotate them, move them closer,further away, and many other things.

A powerful screen-oriented text editor is included to facilitate imageformation. This program was recently featuredon Tom Snyder's PrimeTime Saturday TV Show and is now available for sale.

APPLE WORLD'S powerful editor is so easy to use that children will love itYou can now "sketch" your dream house, boat, car, or fantasy empire.Then view it as it would be seen from 10,000 feet, or you can ZOOM inuntil the screen is filled with a doorknob. You could then go inside andmove from room to room examining furniture placement as your screenrotates within the room. Images or specific parts of images can easily besaved to disk or printer.

Does all this sound like science fiction? You won't think so after you have

visi,ed AppleWorld Introductory Price $59.95

36 page manual includedLook for USA's Red-White-Blue Software Rack at your localcomputer store or send in your order plus $1.00 shipping to:

United Software of America

7503rd Ave., New York, NY 10017(212)682-0347 Dealer Inquires Invited J

USA

Circle 161 on inquiry card.

BYTE May 1980

245

Circle 163 on inquiry card.

Circle 165 on inquiry card.

Buy By Mail and Save!

COMPUTERS

INTERTEC SuperBrain®

32K RAM $299564K RAM $3345

$2495$2695

NORTH STAR Horizon® 1

32K Kit, List $1999 . $1579

32K Assembled $2695 $2149Horizon 2

32K DD, Kit, $2399 . $1885

32K DD, Assm. $3095 $2439

32K QD, Kit $2779 . $2359

32K QD, Assm. $3595 $2859

CROMEMCO

System 3, 64K, $6990 . $5479System 2, 64K, $3990 . $3179Z 2, List $995 $ 829

VECTOR MZ, $4313 $3439

System B, List $5463 $4359

HEATH WH 89 .

$1949

DISK SYSTEMS

THINKER TOYS®

Discus 2D; $1149 . . $939Discus 2+2, $1549 . . $1288

PRINTERS/TERMINALS

ANADEX DP-8000 . . $869

PAPER TIGER IDS 440 $849

with graphics option . . $949

INTERTUBE II, $995. $729

PERKIN ELMER

Bantam 550 $789

SOROC 120, List $995 . . $745

TELEVIDE0 912 . . $789

CENTRONICS 730-1 $799779-1, List $1245 . . . $939779-2, List $1350 . . . $989

T.I. 810 $1575

Most items in stock for immediate delivery, factory-sealed cartons, with full factorywarranty. N.Y.S. residents add appropriate sales tax. Prices do not include shipping.VISA and Master Charge add 3%. COD orders require 25% deposit. Prices subjectto change and offers subject to withdrawal without notice.

Computers Wholesale

P.O. Box 144 rSHKl

Camillus, NY 13031 jffl Si

win L" " EZY

(315)472-2582 MSlS

The world's most popular microcomputer, with 16K ofmemory and Level 11 basic for only $720, complete withfull 90 day Radio Shack warranty. We accept check,money order or phone orderswith Visa or MasterCharge.(Shipping costs added to charge orders).Disk drives, printers,peripherals, softwareand games . . . youname it, we've got it(Both Radio Shack &other brands). Writeor call for ourcomplete price list.

Shown ts Lavel I.Level II includesAlphanumeric keypad.

C&S

ELECTRONICS MART

Ltd.

AUTHORIZEDDEALERSHIP

Radio /hack

32E.MainStreet«MilanMichigan48160«(313)439-1400

MAKE YOUR BASIC

ilN

Developing business applications without keyed file support is likeproducing a play without the right cast — you can expend needlesstime and money, and end up giving an inadequate performance.Enter MAQBAM"

MAGSAM picks up where your BASIC leaves off by providing itwith a powerful Keyed File Management System that's quick andeasy to use. The result is applications that do exactly what you wantthem to — instead of only what BASIC allows you to.Supporting Cast

MAGSAM's advanced features and capabilities include:

• Random, sequential, and generic access by key

• Secondary indexing with any number of keys

• Key and record deletes with automatic space reclamation

• Dynamic file allocation and extension

• Complete compatibility with BASIC files

• Interactive tutorial program

• One year update service

The versatile MAGSAM file management is now available in twomajor versions. MAGSAM IV, the new high performance assemblerversion, is ideal for business applications in which response time iscritical. Complete with an interface for CBASIC, MAGSAM IV is$295. MAGSAM III is the standard version and is in use world wide.Written in BASIC, it is available for CBASIC. Microsoft BASIC, orMicropohs BASIC for $145. The MAGSAM manual alone is S25.You're the Star

MAGSAM is available immediately —off the shelf. So you can beginsaving time and money now while providing your customers andclients with applications that truly meet their needs. Send for a freebrochure telling the full story on MAGSAM. or see a demonstrationat your computer dealer today.

Another Business Solution from:

Micro Applications Group

7300 Caldus Avenue. Van Nuys, CA 91 BOB

n/lME

The system of the 80's

Easy to use

• Fully interactive

• Top down design

• Bottom up debugging

• Structured programming supported

Powerful

• Fast compact code generated

• Recursive and re-entrant

• Interfaces with CP/M'

• Enhanced Forth vocabulary

Versatile

• Machine independent code

• System can be configured as RAM or ROM basedfrom a 2K controller to a 16K development system

Ordering information

• Diskette and documentation $150*

• Documentation only $25

• Please specify which version when ordering

Z80 with CP/M*8080 with CP/M"

• OEM and dealer pricing available upon request

*3>nglesite, non-conirneiual license

The StQckUUorks

321 E. Kirkwood / Bloomington, Indiana 47401(812) 336 1600

246 BYTE May 1980

Circle 164 on inquiry card.

Circle 166 on inquiry card.

Circle 168 on inquiry card.

P&T CP/M® 2 unleashes the POWERof your TRS-80 MODEL II

Pickles & Trout has adapted CP/M 2, one of the world's mostpopular operating systems, to the TRS-80 Model II and theresult is spectacular:

• 596K bytes usable storage at double density

• Runs both single and double density diskswith automatic density select

•Single drive backup

• Multi-drive software can run on a 1 drivesystem

• Operates with 1, 2, 3, or 4 drives

• Full function CRT control•Type-ahead buffer for keyboard input

• Full access to both serial ports and parallelprinter port

• Fully software programmable serial ports

• Loads an 18K Basic in 2.5 seconds

• Full compatibility with existing CP/M softwareand application packages

•Full set of 7 CP/M manuals plus our own forthe TRS-80 Model II

fSoSf

Introductory price: $175

Prepaid. COD. Maslercharge or Visa orders acceptedShipping extra. California residents add 6°i> sales tax

PICKLES & TROUT

P.O. BOX 1206. GOLETA. CA 93017, (805) 967-9563

CP/M is a trademark of Digital Rest

TRS-80 is a trademark of Tandy Corp.

8088 S100 CPU

Want to upgrade your 8 bit system to a 1 6 bitsystem? Don't want to discard your 8 bit boards?The LDP88 offers 1 0 to 20 times the processingpower of your present CPU while retaining com-patibility with your 8 bit memory and peripherals.The LDP88 is a single board computer with com-plete IEEE S100 bus compatibility. The board hasthe following features:

• Up to 8K bytes of ROM/EPROM

• 1 K bytes static RAM

• 8 vectored interrupts

• Serial I/O port

• 1 6 bit instruction set

• 8086 software compatibility

• Address up to 1 Megabyte of memory

PRICE: $399.99 (assembled and tested)

Serial monitor for CRT or TTY: $79.99(Mass. residents add 5% sales tax)

See your March and April BYTE for Steve Ciar-cia's articles about the 8088.

To order send check or money order to:

Lomas Data Products

1 1 Cross Street

Westborough, MA 01 581

Telephone: (617) 366-4335

Circle 167 on inquiry card.

COMPUTERFORMS KIT

EACH KIT CONTAINS:

Samples, Prices, Order Form,

4 Checks, 2 Statements, 2 Invoices,

Programming Guides.

We specialize in small quantities, low prices.500 CHECKS ONLY $29.95

SEND COUPON, CIRCLE BINGO orPHONE TOLL FREE1+800-225-9540

FAST SERVICE - It is our policy to ship within 6 workingdays following our receipt of your order. CODE 459

Name

Address

City

State, Zip

NEW ENGLAND BUSINESS SERVICE, INC. GROTON, MASS. 01450

Circle 169 on inquiry card.

BYTE May 1980 247

Circle 170 on inquiry card

The'Red Box'. Our dynamite duo!

Bit Error Rate Test Set - EIA InterfaceBreakout Panel in pocket size package.

IDS'S MODEL 65/60 lets you both analyze and test at the EIAinterlace between a modem and terminal. Combines ourpopular "Blue Box" model 60 with a new bit error rate test set.All in one light, portable, hard plastic case.Works on rechargeable batteries. Available now.

Circle 171 on inquiry card.

INTERNATIONALI DATA

SCIENCES, INC.

7 Wellington Rd., Lincoln, R.I. 02865Tel. 401-333-6200 TWX 710-384-1911Export: EMEC, Box 1285,Hallandale, Fla. 33009 Telex 51-43-32

niooQOBOiKHiiiooooooaoOQOoiiOiicojQOoaiiiiiiiiDiioiicoiioomiaoDooooaiiooociKioo

TRS-80® CP/M® & CBASIC®BUSINESS SOFTWARE

LOW COST MOD II DISK EXPANSION. . . over 610,000 bytes/disk with ourCP/M . . . plus many other features.

Find out why ours is the Better Business Buy!

Model II CP/M (rel. 2.0) $250.00

Model 1 CP/M (re. 1.5) 150.00

CBASIC 95.00

APH (Automated Patient History) 175.00

RESIDENTIAL PROPERTY ANALYSIS

system 300.00

MAGIC WAND® Word Processor .... 400.00RM COBOL® (Z80 code) 750.00

Osborne & Assoc. CBASIC source programs—

O&A Payroll w/Cost Accounting $250.00

O&A Accts. Rec./Accts. Payable . .. 250.00O&A General Ledger w/Cash Journal. 250.00O&A CBASIC books for above (each).... 20.00

Send 30C SASE for CP/M Users Group softwarelist & free "CP/M Primer".

■ MM..K \a *M)iS j i,-,t^i,-n-l| i?,|j,. ih „! small Business Application* im

■ KM COHOl ,s ., rrvjaipitd tiath-mart ol Ryan Mi I arland Corp

• lKs«Uisj<e.j.sn-i.-<iiidj. liMihuiKdduisn.it k .i ><trxlv<cimpdm

• U*'M 1SJI.-4.sU-1.-d lM(k-HMI* oi Dkjiwl Rvwwi h

• (.ll-\SK. .\ J .t-ijiilfied r.dd.-mdik ol S.)1I».in- Msh-m,

(714) 848-1922

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Fully TRS-80®Compatible

MPI B/51

DISK DRIVE

Includes: Case and Power Supply

In Stock!Limited Quantities.

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Save time... Order by phone

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Hundreds ot other computerproducts at ma|or savings.

1BK Memory Kits300ns 25Cns 200ns

Cables TRS-Sfl

Diskettes PrintersOperating Systems

MidwestComputerPeripherals

P.O. Box 437 • Wllmette, Illinois 60091

For Business Systems Software

Programmers Only!!

Machine Language

ISAM

FOR

TRS-80* Models I and II

ACCESS TIME V2 SECOND!!

This machine language ISAM ROUTINE provides file accesssophistication required to implement complex business software,and is completely compatible with TRS-80* BASIC.

Specifications: based on 1000 record file, key length of 6, datalength of 64

Access time oi Vz second

Best add/delete time oi 1 second

Average add/delete time of 2 seconds

Worst case add/deleie time of 5 seconds

Keys up to 25 characters

Data up to 255

Provides next highest key upon each file access.

Preset range of allowable key values, set upon file creation up to 4 files

held open concurrently.

No special utilities needed to "Reclaim" used record space.

Model I Routine occupies 5 K of user space (loads at top of user memory)

Model II Routine occupies 6 K of user space (loads at top of user memory)

EOF, file full, empty, key not found, INVALID key value and all

TRS DOS* error codes supported.

TRS-80 Model I (32 K + 48 K only) $160.00TRS-80 Model II (64 K only) $170.00

Includes: All necessary documentation, file creation program, fileinspection program, machine language ISAM routine and loader.

RELIABLE COMPUTER RESOURCES

415 MILLBURY STREET

WORCESTER. MA 01607

(617) 755-8134

'TES-80 and TUS DOS are trademark of Tandy Corporation, which has no relationshipto RCR Inc.

INC TV

248 BYTE May 1980

Circle 172 on inquiry card.

Circle 173 on inquiry card.

Circle 174 on inquiry card.

MIEAM

OSBORNEBUSINESS SOFTWARE

in CBASIC2 or CROMEMCO 16K BASIC

* hardware required

* features *Four Complete Packages—

• General Ledger

• Accounts Receivable

• Accounts Payable

• Payroll with Cost AccountingStrong support from Osborne ManualsCBASIC2 runs under CP/M or under CDOSversion 1.07 on Cromemco computersI6K BASIC runs on Cromemco computersCursor addressing routines for Hazcltine,Lear Sieglerand Cromemco (Beehive)Terminals

Source Codes and Installation Instructions

provided along with disks

Automatic Command Start-up

Easy to apply to all of your business and

systems needs

One or more 8" or 5" Floppy

Drives

CRT with cursor addressing

132-Column Printer

$95

perpackage

• DEALER INQUIRIES INVITED.

MIC

AH'S PRODUCTS OF D1STINI

HON

. ossoRNf business

■ DO/1 (Dfsfc Utilities

• EXPAND (Run Cro

neiTt-

SOI IWAKE (in CBASIC2

iui ti'/M and CDOS)

CO Sufiware on CP

8. 16K|

• IJUP/2 IDisk Utilises foi

• BLACKJACK (Tuioi

al

«( BIOS (CP/M for

( romemeoj

Casino Virion)

( romemco Computers]

• DOP/3 (D0P/2 Expanded)

. DKlvt iCtistomizef

iMK KCM'IOT (Versatile

• SPOOL [Cromemco

Printer Driven)

Pnntei Graplucsj

formal Utitity]

• DBMS Conversion

o NAD

• Call or Write for Free Catalogue and More Information •* We will Customize any of our programs at our Standard Consulting Rates +

Ah! NilEAU . . . .Satisfyin' Software

That turns your system on!

MICro Applications and Hardware

• CONSULTANTS and SOFTWARE DEVELOPERS .

— MICAH Box 22212 San Francisco, California 94122 USA phone: 415/664-0778

J

O FROM THE ORIGINATOROF THE TRS-80 PROJECT...

FMG Corporation—forHIGH LEVEL LANGUAGESU FORTRAN

□ PASCAL

□ COBOL

□ BASIC

SEND FOR

SOFTWARECATALOG

Microcomputer soft-ware for businessapplications, en-gineers, consum-ers, hobbyists andothers who have aserious interest incomputers.

VISA*

• CP/M — Industry StandardOperating System

•USCD PASCAL PACKAGE•GENERAL LEDGER; PAYROLL;

ACCOUNTS RECEIVABLE and

ACCOUNTS PAYABLE

• FORTRAN-80 PACKAGE — NewCapabilities for TRS-80 Users

• FMG's MICRO COBOL — ForTRS-80 and TRS-80 Model II

• CP/M Z80 — Macro Assembler

• ZSID — Symbolic Debugger

• Custom Programming, Service,Installation and Training areAvailable at Additional Cost

FMG Corporation is an IndependentSoftware Company — from the ORIGI-NATOR OF THE TRS-80 PROJECT andTHE AUTHOR OF THE FIRST CP/M FORTHE TRS-80.

CORPORATION

5280 Trail Lake DriveSuite 14

Ft. Worth, Texas 76133(817) 294-2510

CP M is a registered trademark of Digital Research Corp.TRS-80 is a registered trademark of Radio Shack.

HEATH® COMPATIBLE

DG-32D 32K RAM FEATURES:

f' Plugs into Heath" H8 Computer.

v* Ready to use. Fully assembled, tested &

burned in.v* Operates with existing Heath " memory.W Protected memory Output Buffers in the

event of Address error.*•" Utilizes popular 4116 RAM devices.i^ Memory Address DIP switch changeable.<** Arranged as 4 Independent 8K Blocks.V Low Power Consumption: Less than 6 watts,

typical.*"* Transparent Refresh.k* One year guarantee.V* Compatible with all current H8 peripherals.

D«G Electronic Developments Co.brings you a totally compatible, fullyassembled and tested 32K RAM forHeath" H8 computers. The DC-32Dhas less than 6 watts power con-sumption. This allows you to add a full32K bytes of Random Access Mem-ory without taxing or replacing yourcomputer's power supply. Engineer-ed to plug-in and run withoutany usermodifications, the DG-32D can be

Heath " and H8 are registered trademarks of theHeath Corporation, Benton Harbor. Michigan.

used with or without existing H8 RAMwithout modification. Protection ofthe memory output buffers is provid-ed in the event of assigning twoblocks to the same address space.The DG-32D is the ideal answer toexpansion of the Heath" H8 com-puter. . . Low power consumption,low price, high capacity, total engi-neering and exacting productionmethods.

BURNED IN 16K MEMORY CHIP SETH88-H89 $89.00

ORDERING INFORMATION: DC 32D RAM available only from DG Electronic Developments Co.. P.O. BoxI I 24. 182 7 South Armstrong, Denison. Texas 7 5020. Check, money-order. VISA or Master Charge. Phoneorders accepted on charge orders. NO COD s. Foreign orders add 30%. Texas residents add 5%. For VISAor Master Charge orders call 2 14-465-7805. $479,00 freight prepaid Allow three weeks for personalchecks to clear banks.

□•B

DEVELOPMENTS CO.

32KRAM $479

Circle 175 on inquiry card.

BYTE May 1980 249

Error Checking and Correctingfor Your Computer

Gregory J Walker, PresidentDesign Innovations, Inc

Birch AcresNew London NH 03257

An active error-checking and cor-recting system can go a long waytoward solving the occasional prob-lems that hamper the usefulness oflow-cost data-storage devices (such asaudio-cassette recorders). It offers ameans of improving reliability inproblem-plagued situations, and incases where the error frequency isalready sufficiently low, the checkingand correcting system allows in-creased data densities and transferrates with an overall gain in storagesystem performance. In a well-designed system, error detection andcorrection schemes can lead tomarked reductions in loading timesdue to higher average data rates.

Figure 1 shows the connection ofthe active error-checking and correct-ing apparatus between the computerand the peripheral data-storagedevice.

The theoretical development oferror-trapping and correcting codes islargely due to the efforts of RichardW Hamming, a mathematician whofirst published on the subject in theBell System Technical Journal earlyin 1950. (See reference 1.) Now,thirty years later, Hamming codesstill represent one of the more prac-tical approaches to the error-correcting problem.

A particularly important aspect of

Hamming's work focused on his for-mulation of the concept of codedistance (indicated by the letter D).This relates the uniqueness of (or"distance between") meaningful codesto the number of simultaneous errors(indicated by the Greek theta, 0) thatcan be detected and corrected.

PROCESSOR

i^>

SYSTEM BUS

7~>

DEVICE INTERFACE S^,

LA

ERROR CHECKINGAND CORRECTING

MODULE

MASS DATA

STORAGE

HARDWARE

Figure 1: Block diagram showing inter-connection of error-checking and correct-ing system with the computer.

Definition of Hamming Distance

The Hamming distance betweenany two words is defined as thenumber of bit positions in which theydiffer. In terms of logical processesthis is merely the total number of bitsset to logic 1 following an exclusive-OR operation between the twowords, as shown in figure 2. Simplebinary coding has a Hammingdistance of 1. This unitary distance isprecisely the source of the problem,because any given code value appearsto be as valid as any other.

Normally, as a processor receivesbinary data from a peripheral device,no mechanism is present which cancorrect a bit inversion. If a bit is readerroneously, it will either invalidatethe check sum and cause an errortrap, or it will be loaded into mainmemory without detection, thuspropagating the error. It may or maynot be a critical fault.

Consider the following 4-bit code:

'mbol

Encoded Form

bit 3210

0

0001

1

0010

2

0100

3

1000

This limited shifting patterngenerates a code format with a Ham-

250 May 1980 © BYTE Publications Inc

Circle 176 on inquiry card.

Circle 177 on inquiry card.

ELECTRONICS, Dept.5-B1020 W. Wilshire, Oklahoma City, OK 73116

WE CARRY -

• CROMEMCO

• NORTH STAR

• VECTOR GRAPHICS• THINKER TOYS

• NEC

• CENTRONICS

• INTERTUBE - $750.00

• SERENDIPITY

• SOROC - $775.00

• TEXAS INSTRUMENTS

Professional A/Ft, A/P, Ledger, Payroll, Medical Billing soft-ware with customization available. Send for our catalog —Send for quote.Call for quote.

SARA-TECH

COMPUTERS

P.O. Box 692

Venice, FL

33595

(813) 485-3559

Why pay more... and get less?

Sirius gives you lower prices and higher quality!

Remex RFD 4000/00018" Floppy Disc DrivesDouble sided...Double density!!

$549!

|95

RFD 4001, $564.95

Offers quality and features found in drives costing muchmore! ■ Single or Double Density ■ Double-Sided Drive ■ Door Lock INCLUDED■ Write-Protect INCLUDED ■ 180 Day Warranty ■ Compatible with Shugart850/851 ■ Low Power Operation ensures LONGER LIFE!! ■ Model RFD 4001 offersData and Sector Separator

AVAILABLE OPTIONS/ACCESSORIES

□ Single Drive Power Module, $119.95 D RFD4000 Manual. $5.95 Q Drive Cabinet, $29.95

□ Dual Drive Power Module, $139.95 □ Interface Manual, $2.95

Remex 1000B... if you've been lookingfor a less expensive floppy disc drive,but not wanting to sacrifice quality —this is It!

$419

95

You get both in the Remex 1000B! For only $419.95 look

at what you get: ■ 8" Floppy Drive ■ Single or Double Density

■ Hard or Soft Sectoring ■ Media Protection Feature ■ Single Density

Data Separator ■ 180 Day Factory Warranty

AVAILABLE OPTIONS/ACCESSORIES

□ Door Lock. $19.95 Q Connectors, $9.95

□ Write-Protect. $19 95 Q DriveCabinet, $29.95rj Interlace Adapter {Remex to Shugart}, $12.95

□ Interface Manual. $2 95

□ 1000B TechnicalManual, $5 95

SIRIUS mpWm Series...perfect add-ons for yourTRS-80*!

■ Comes complete ready to plug In and run!

■ 5ms track to trackm SIRIUS 80+1 and80+2 — up to

102,000 bytes

■ SIRIUS 80+3 and 80+4 —240K and480K bytes

SIRIUS 80+1 (Single Head) $349^5

SIRIUS 80+2 (Dual Head) $419.95

SIRIUS 80+3 (Single Head) $439.95 SIRIUS 80+4 (Dual Head) $539.95

MPI 51/52 ... A Great Reliable Mini-Drive!

■ Fast! 5ms track to track access

■ Exclusive Pulley-Band Design

■ Unigue DoorlEjector Mechanism

■ Reliable PhX Speed Stability

MPI51 <9«;q <k

(Single Head) ?^33.33MPI-52 (Dual Head) $349.95

MPI 91/92... MoreDrive For Your Money!240K/480K!

MPI-91 (Single/240K) $349.95MPI-92 (Dual/480K) $449.95•TRS-80© Tandy Corp,

SIRIUSSYSTEMS

(615)577-1072

P.O Box 9748, Knoxville. TN 37920Phone Orders accepted 9AM-7PM (EST)VOLUME DISCOUNTS AVAILABLE

Circle 178 on inquiry card.

BYTE May 1980 251

0000000000000001

0000000011111110

0101010110101010

} 10100110

} 00000001

} 11111110

} 11111111

Figure 2: The logical exclusive-OR func-tion produces the output bytes shown inthe right column from the input bytesshown in the left column. For each bit, theoutput bit is a 1 if and only if one of theinput bits is a 1.

Hamming Distance(Minimum)

12345

code uniqueness

single-error detection

single-error correction

single-error correction/double-error detection

double-error correction

Table 1: Minimum Hamming code distances necessary to obtain the listed propertiesin a particular coding scheme. Capabilities increase directly as Hamming distance in-creases (for small distances). Correction of an arbitrary number of errors requires aHamming distance of at least twice the number of errors plus 1.

ming distance of 2. It is impossible toinvert a single bit position and createany one of the other three validwords.

Symbol

3

Encoded Form

1000

Symbol

3

INVALID

Encoded Form

1000

1100

However, if a dual error occurred,the code's error-detection capabilitywould fail:

U

2 0100

As indicated above, when theHamming distance increases, theallowable number of simultaneouserrors, 6, also rises. Errors can betrapped effectively as long as 8 doesnot equal or exceed the Hammingdistance minus 1 (D — 1). Thisshould be clear, any sequence of

- - Texas Instruments - - -fo Home Computer Ti-99/4

y

Math Speech Diet

Modem

Thermal Printer

RS 232 Interface

Disk-Controller

Disk Drive

Joystick (pair)

Dual Cassette Cable

Video Graphs

Early Learning Fun

Beginning Grammar

Early Rdg&Spch Die!

Diagnostic

Home Financial Decisions 29.95

Football

Physical Fitness

Household Budget Mgl

Tax/Invest RecKpg

Investment Analysis

Personal Record Keeping 49 95

Statistics

Video Chess

Number Magic

Speech Editor

Speech Synthesizer

Terminal Emulator

f

ORDER

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Superior color, music, sound and graphics—

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Plus a unique, new Solid State Speech Synthesizer.

FACTORY DIRECT SALESDipt. 47

1317 E Colorado SI.Glondlle. CA 91205Phono: (213) 245-1417

•26K ROM

• Up to 72K totalmemory capacity

• 16-color graphics 3.capability a**l

• Built-in equationcalculator

Calilornia residents add 6% sales tax. Delivery subject to product

■ SATISFACTION GUARANTEED OR YOUR MONEY BACK! availabil'iy by manufacturer

Price subject lo change without notice Relunds guaranteed252 May 1980 © BYTE Publications Inc

(D — 1) errors will result in thegeneration of a meaningless codeword if the distance between codewords is given by D. No series of(D — 1) errors will produce a mean-ingful code.

Correcting Errors

Error-correcfioM capability neces-sitates a larger Hamming distance, asshown in table 1. Any pattern of 6 er-rors can be corrected if, and only ifthe Hamming distance D is greaterthan or equal to (26 + 1). In this case,any received data word with 6 errorsdiffers from the transmitted, correctword in 6 positions, but it also differsfrom all other meaningful words in atleast (20 + 1 - 6), that is, (6 + 1)positions.

The erroneously received wordtherefore lies closer to the correcttransmitted word than to any otherpossible word. Thus, it is possible toreconstruct the proper coding andrecover the correct data word. Toillustrate this point, the 4-bit codefrom the previous example does notmeet the criterion of D greater than orequal to (26 + 1), and is therefore un-correctable. A single bit error ineither of the two positions can lead tothe same erroneous code:

Symbol

Encod

ed Form

3

1000

1

INVALID

1010

t

1

0010

Examination of the invalid code(1010) yields no information concern-ing what the correct pattern was ini-tially. This meaningless value (1010)

Circle 180 on inquiry card.

Circle 181 on inquiry card.

SuperBrainSoftware.

MICROSOFT

C-BASIC

PRICE

A/R

X

X

$250.00

A/P

X

X

$250.00

G/L

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$250.00

P/R

X

X

$250.00

Inventory

X

X

$250.00

Restaurant Payroll

X

$250.00

Mailing List

X

$150.00

Word Processing

X

$195.00

"Industry Standard" programs on 5V*"diskette include source and complete profes-sional documentation. Ready to run on Super-Brain.® One time charge, non exclusivelicense.

■ ■■ COMPUTERQQQ MARKETING

■ ■ ■ CDRPOR ATXDTJ

116 South Mission

Wenatchee, WA 98801

(509) 663-1626 Ask tor wholesale division

Also SuperBrain® computers check on prices.* Trademark of Intertec Data Systems

Z^-SYSTEMS

3 ZOBEX INC.

Complete computer on 3 S-100 boards for

UNDER $1000.00*

Runs M/PM, C/PM and OMNIX

64K RAM

4 MHz

No WAIT States

IEEE Std.

Low power,

DMA operation,

Bank select in 16K sections

Can be disabled in 4K increments

i i

Z80 CPU

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3 serial ports, 3 parallel, one 4KEPROM, Vectored interrupts, real timeclock, Software controlled baud rates,

1 1

Drives daisy wheel printer directly

DISK CONTROLLER

8" and 5"DRIVES

All digital design for stable andreliable performance. No one-shots or analog circuitry.

i i

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SEND FOR FREE INFORMATIONS

6 months warranty on our boards with normal use

ZS-SYSTEMS / ZOBEX INC.

P.O. Box 1847, San Diego, Ca. 92112(714) 447-3997

•introductory offer for limited time only

64K BYTE EXPANDABLE RAM

DYNAMIC RAM WITH ON BOARDTRANSPARENTREFRESH GUARANTEED TO OPERATE INNORTHSTAR. CR0MEMC0. VECTOR GRAPHICS.SOL. AND OTHER 8080 OR Z-80 BASED S100SYSTEMS *4MHZ Z-80WITHN0WAITSTATES.

* SELECTABLE AND DESELECTABLE IN 4KINCREMENTS ON 4K ADDRESS BOUNDARIES.

* LOW POWER-8 WATTS MAXIMUM.

* 200NSEC4116RAMS.

* FULL DOCUMENTATION.

* ASSEMBLED AND TESTED BOARDS AREGUARANTEED FOR ONE YEAR ANDPURCHASE PRICE IS FULLY REFUNDABLE IFBOARD IS RETURNED UNDAMAGED WITHIN14 DAYS.

ASSEMBLED/TESTED

64KRAM $595.00

48KRAM S529.00

32K RAM $459.00

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BYTE May 1980 253

could have been generated from anoriginally encoded 3 (pattern 1000),with an error in bit 1, or from an en-coded 1 (pattern 0010) with an errorin bit 3. Without any additional in-formation, it is impossible todistinguish between these cases. Oncean error occurs, although it can betrapped by searching for invalidcodes, it cannot be corrected.

Now consider the correctable code:

Symbol

01

23

Encoded Form

00000111011101000111

Examination of this new codereveals a minimum Hammingdistance (D) of 3 between the variousstates, permitting single error correc-tion. (See table 1.) The inefficiency of

Symbol

Binary Form

7-bit Encoded Form

00

0000

1110000

01

0001

1000001

02

0010

0100010

03

0011

0010011

04

0100

0000100

05

0101

0110101

06

0110

1010110

07

0111

1100111

08

1000

0011000

09

1001

0101001

10

1010

1001010

11

1011

1111011

12

1100

1101100

13

1101

1011101

14

1110

0111110

15

1111

0001111

Table 2: Sixteen differen

t logical entities or

symbols

can

normally be represented by

a 4-bit code. Use of a

unique 7-bit encoding

increases

the

Hamming distance to 3 and

allows a single-bit error

correction.

this code is obvious; however itshould be clear that any single errorcan be detected and located using thisscheme.

Symbol

0

INVALID

Encoded Form

00000

00001

The erroneous pattern could onlybe the result of encoding a 0 with aninversion in the least significant bit.Given the word 00001, the original,correct coding could be restored. Thiscan be attributed to the fact that eventhe invalid, meaningless patternsdisplay a limited uniqueness, and aredirectly traceable to specific validcodes subject to a small number oferrors.

Uses of Parity

Clearly, coding efficiency ishampered as the Hamming distance isincreased and as the requirements fortrapping and correcting power aremade more stringent. It becomes amatter of systematically generating acode that displays enough "correctingpower" to handle data words of auseful length, without creating an ex-cessive code-redundancy overhead.Here, the concept of parity plays animportant role. Parity is establishedin a data word through the setting ofan additional bit, such that the totalnumber of bits set to logic 1 is eitheralways odd or always even.

The operation of simple parity en-coding and decoding is easy tounderstand. Assume, for example,that a data word 4 bits wideundergoes an odd-parity test acrossthe entire word:

"1010

1 1010

During encoding in this example,the fifth bit (the parity bit) is set toestablish odd parity. Upon decoding,if the parity bit is included in an iden-tical parity check, namely odd parityacross the entire word (now 5 bitswide), the output of the parity testwill be a logic 0.

If at some point between encodingand decoding, an error forces an in-version in a single bit (eg: with anerror in bit 3, input to the decoderwill be 10010), the odd-parity test will

254 May 1980 © BYTE Publications Inc

Circle 182 on inquiry card.

Circle 183 on inquiry card.

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Circle 184 on inquiry card.

BYTE May 1980

255

2

0 3 2 10

PARITY

LEVEL

1 0

1 1 1 0 1

i

L

PBO

(ODD)

PB 1PB2

(ODD)

(ODD)

PARITY

GENERATOR INPUT:

1 IOI-n

3 BIT

PARITY OUTPUT:

101 J

PARITY/DATA BLOCK WRITTEN:

1011101

2 1

0 3 2 10

FAULT

LEVEL

1 0

1 1 1 0 1

FCO

(ODD)

FCI

(ODD)

FC2

(ODD)

FAULT

CODE

SYSTEM TRAP INPUT:

IOIIIOI

ERROR

NONE

FAULT

CODE CREATED:

000

Figure 3: Sixteen different logical states may be represented in a 7-bit code with aHamming distance of 3. Single-bit errors may be detected and corrected. Encoding in 7bits is accomplished by performing three distinct parity checks on 4 data bits. Table 4shows the possible fault codes. The fault code of 000 indicates that no error wasdetected in decoding.

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immnwwra *

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fail and produce a logic 1 signifyingan error.

Operation of Hamming Codes

Certainly this mechanism can befooled by multiple errors, but it ispossible to construct multiple-levelparity checks which will trap a sur-prising number of errors. This isprecisely how the Hamming codesoperate. Fundamentally, Hamming'salgorithm performs multiple-levelparity generation on a data word atthe data source. This parity code isthen transmitted along with the data,and the entire code block (data plusparity code) is subsequently decodedunder an analogous process. Any biterrors occurring during transmissionwill be detected.

Clearly, the efficiency of this errortrap will approach 100% only in verysimple cases. Several parameters havedirect bearing on the trapping suc-cess: total word length N, number ofdata bits K, number of parity bits M(M = N - K). The ultimate goal, ofcourse, is to realize the ideal wherethe quantity N/K approaches 1, andM is minimized without sacrificingtrapping and correcting capability.

A 4-bit binary code is normallycapable of representing sixteen dif-ferent states with a Hammingdistance equal to 1. Momentarily set-ting aside questions of efficiency, thesame sixteen states can also berepresented in a 7-bit code at triplethe Hamming distance, as shown intable 2. Again, referring to table 1, aHamming distance of 3 facilitatessingle-error correction. Encoding in 7bits is accomplished by performingthree distinct parity checks on the 4data bits. Details of the three paritychecks are summarized in table 3 anddiagrammed in figure 3.

It should be understood that theactual encoded form of each symbolis irrelevant and need not be known.When no error is present, decoding ofthe 7-bit word will reset all three par-ity checks to logic 0, and will restorethe data to its original form. Theerror-handling process isdemonstrated in figure 4. With anerror in the third data bit, the parity-decoding procedure flags a fault codeof 110, which in table 4 is seen to cor-respond uniquely to an error in dataposition 3.

256 May 1980 © BYTE Publicalii

; Inc

Circle 185 on inquiry card.

Circle 186 on inquiry card.

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Circle 188 on inquiry card.

BYTE May 1080 257

Admittedly, this does not con-stitute a true Hamming code, in thesense that the fault code does notdisplay the binary form of the error-bit position within the word. Thisfeature is convenient to implementfor the shorter codes, but need not beattempted in the more comprehensive

correction schemes where fault-codeinterpretation can be readily handledin a read-only memory.

Practicality of Use

An overhead of three parity flagsfor every 4 data bits is undesirable.These techniques become useful only

2

0 3

2 1 0

1 0

1 1

1 0 1

i

L

— — —

PARITY

GENERATOR

INPUT:

PARITY

OUTPUT:

PARITY/DATA BLOCK

WRITTEN:

2 1

0 3

2 1 0

1 (

)

1 0

1 0 1

FAULT CODE

ERCC TRAP INPUT:

ERROR:

FAULT CODE CREATED:

PARITY LEVEL

PBO

(ODD)

PBI

(ODD)

PB2

(ODD)

HOI

101

1011101

FAULT

LEVEL

FCO

(ODD)

FCI

(0D0)

FC2

(ODD)

1010101

DATA BIT 3

110

Figure 4: Another example of encoding and decoding data composed of 4 bits in a 7-bitword. In this case an error has been detected; the fault code of110 indicates an error indata bit 3.

for larger word lengths. Initially, per-formance increases as the data wordlength becomes longer, up to N = 31.It is possible to correct single-biterrors in words with 8 data bits andfour additional parity flags, anoverhead of 50%. Single-error cor-rection of 16 bits requires five flags,an overhead of 32 %.

In the case of an 8-bit system, anoverhead of 50% may seem exorbi-tant, but it can pay off rapidly.Assuming that with correcting logicin operation, single errors are virtual-ly nonexistent, it may well be possibleto realize a decrease in loading timeby a factor of 2, 5 or even 10. It is truethat 1.5 times as many bits are beingmoved into and out of the storagemedium, but if the data rate merelydoubles, loading times will fall to

Check Bit

012

Data Positions

0,1.20,2,31,2,3

(odd)(odd)(odd)

Table 3: Encoding 4-bit data into 7 bitsis done by performing 3 distinct paritychecks on the 4 data bits. Each of the 3check bits corresponds to the parityvalue of the data positions shown here.

5

'

0 7 6 5 4 3

0 I 0 0 I 0 1 0

J

L

1 — — _

PARITY GENERATOR INPUT:

PARITY OUTPUT:

PARITY/DATA BLOCK WRITTEN:

1 0

PARITY LEVEL

1 0

PBO (ODD)

PBI (ODD)

PB2 (EVEN)

PB3 (ODD)

01010110

1010

10IOOI 0 101 10

RR

FAULT CODE

ERCL TRAP INPUT:

ERROR:

FAULT CODE CREATED:

3

2

1 0

FAULT LEVEL

0

1

1 0

—

—

FCO (ODD)FCI (ODD)FC2 (EVEN)

FC3 (ODD)

i oi oo 11 ioiio

DATA BIT

5

1100

Figure 5: Encoding and decoding for data consisting of an 8-bit byte. Four bits are used for error checking; the possible fault codesare given in table 6.

258 May 1980 © BYTE Publications Inc

Circle 189 on inquiry card.

Circle 190 on inquiry card.

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Circle 191 on inquiry card.

BYTE May 1980 259

04

03

02

01

00

15

14

13

12

II

0

1

1

1

0

0

1

0

0

0

i

11L

10 09 08 07 06 05 04 03 02 01 00I 0 0 I 0 0 I I I 0 I

PARITY LEVEL

CBO (ODD)

CBI (EVEN)

CB2 (ODD)

CB3 (EVEN)

CB4 (ODD)

PARITY GENERATOR INPUT:PARITY OUTPUT:PARITY/DATA BLOCK WRITTEN:

OIOOOIOOIOOIIIOIOHIO

oniooioooiooioomoi

Figure 6a: Encoding of 16-bit data using five bits for error checking; this results in a 21-bit data word being written to the peripheraldevice. Check bits based on even parity are set to 1 if there are an even number of Is in the corresponding data-bit group; an odd-parity check bit is set to 1 if the number of Is in its data-bit group is odd. This figure, figure 6b, and table 8 originally appeared inslightly different form in Electronics magazine, November 13, 1975, page 135. Copyright © McGraw-Hill Inc, 1975.

04 03 02 01 00 15 14 13 12 II 10 09 08 07 06 05 04 03 02 01 00

01 I 10 OOOOOIOOIOOIIIOI

FAULT LEVEL

FCO (ODD)FCI (EVEN)FC2 (ODD)FC3 (EVEN)FC4 (ODD)

1 I J I 1

0 0 I 0 I FAULT CODE

TRAP INPUT:

ERROR:

FAULT CODE CREATED:

01 I IO0O0OOIOOI0OII 101

DATA BIT 14

00101

Figure 6b: Decoding and checking the 16-bit data, 5-bit parity-check word from figure 6a. Bit 14 has been transmitted erroneously;therefore a fault code of 00101 (reading from check bit 04 to bit 00) is generated. A complete list of possible fault codes is given intable 8 (in reverse order, reading from check bit 00 to bit 04).

Fault Code

Error

000

no error detected

001

check bit 0

010

check bit 1

011

data bit 0

100

check bit 2

101

data bit 1

110

data bit 3

111

data bit 2

Table 4: Look-up

table of fault codes

used by the 4-bit

into 7-bit encoding

scheme. The fault

code tells the error-

correcting logic where the error has oc-

curred.

75% of the initial value. A ten-foldincrease in data rate decreases loadingtime by 85%. Sixteen-bit systems areeven better suited to the use of errorchecking and correcting systems(ERCC), though the majority ofmicroprocessors in use today operatewith an 8-bit data word.

Encoding for 8 and 16 bits is shownin figures 5 and 6. The detailed paritytests for these appear in tables 5 and 7respectively. The fault-code look-uptables are shown as tables 6 and 8.This 16-bit system was developed bythe Data General Corporation. It willcorrect single-bit errors throughoutthe entire word, and will reportedlytrap an average of 97% of the multi-ple faults that occur. Eight-bit codinglogic has been verified in macro-assembler routines on a DECsystem10 by my associate Stephen J Gross,who is now at Stanford University.

Error-Reducing Hardware

Hardware implementation utilizesstandard 7400 series transistor-transistor logic (TTL). Schematicdiagrams are shown in figures 7 and8. Parity encoding and decoding is ac-complished with 9-bit parity trees (us-ing a 74180 parity generator/tester).

Check Bit

Data Positions

0

0,1,2.6

(odd)

1

0,3,4,6,7

(odd)

2

1,3,5,6,7

(even)

3

2,4,5,7

(odd)

Table 5: Encoding of 8-bit data re-

quires the use

of four parity

bits to

allow single-bit

error correctio

n. The

correspondence

of each check

bit to

specific bits within the 8-bit data byte

is shown here.

Worst-case data path for both 8-bitand 16-bit error checking and correc-ting amounts to about 120 ns delay.Certainly, this interval is shortenough to prevent it from imposingany constraint at even unusually highdata-transfer rates. It should be clearthat when handling errors, operation

260 May 1980 © BYTE Publications Inc

Circle 192 on inquiry card.

PET TWO-WAY RS-232

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• Input capability from TV camera or other sources

• Variety of synchronization choices

• 2 selectable video 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 & 256K 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

= 441 California Ave., Palo Alto, CA 94306

415/494-6088

Circle 193 on inquiry card.

Circle 194 on inquiry card.

BYTE May 1980 261

DO O"

Dl \~>~

D2 O-

D3 \Z>-

D4 O

D5 O-

D6 O-

D7 Q>-

5 V4

II 10 9 8

D C B AODDINPUT ICI

74180

EVENE F CLEAR HINPUT

1ODD

JT

12 13

12 II 10 9 8

E D C B AEVENINPUT IC2 2

74180 ODD

ODDF CLEAR H INPUT

13

12 II 10 9 8

E D C B AODDINPUT IC3

74180

EVENF CLEAR H INPUT

s

ODD

13

II 10 9 8

D C B AODDINPUT J.C4

74180

2

ODD

EVENE F CLEAR H INPUT

12 13 I

-O DO-O Dl-O 02-O 03-O 04-O D5-O D6

-O po

-O pi

-O P2

-O P3

Figure 7a: Schematic diagram of electronic logic that encodes 8-bit data. Unused input pins on the 74180 parity-generator and testerdevices are connected to ground.

do O-di C^

D2 O"

D3 rz>-D4 o-

05 O-D6 \Z>-07 £>■

po O-

Pl O"P2 O-P3 O-

+ 5VA

10

8

E D C B AODDINPUT IC5 £

74180 0DD

EVENF CLEAR H INPUT

JT

13

8

F E D C B AEVENINPUT IC6 J

74180 0DD

ODDCLEAR H INPUT

LI ODD

F E D C B A

INPUT IC7

74180

EVENCLEAR H INPUT

ODD

10

8

E D C B AODD

INPUT IC8 ■£

74180 000

EVENF CLEAR H INPUT

-O 00-O 01-O D2-O D3-O C4-O 05-O D6-O 07

-O F2

-O "

Figure 7b: Schematic diagram of circuit for trapping errors in the 8-bit data encoded by the circuit in figure 7a. The 12-bit wordreceived from the peripheral device is separated into 8 bits of meaningful data and 4 bits of parity-checking data. Unused inputs onthe 74180s are grounded.

of the error checking and correcting bits, the generation and interpreta- interface modification is necessaryapparatus is rapid enough to make it tion of these flags are contained en- Additional data-transfer logic is re

apparatus is rapid enough to make itentirely transparent to the processorand the system bus.

Though the underlying theory re-quires the writing of additional parity

tion of these flags are contained en-tirely within the error-processingsystem. (See figure 9.) The parity bitsdo not appear on the bus and are notseen by the processor; therefore no

Additional data-transfer logic is re-quired to deal with the parity bits.The circuits in figures 7 and 8 createparallel data which must undergo a

Text continued on page 274

262 May 1980 © BYTE Publications Inc

Circle 195 on inquiry card.

Circle 196 on inquiry card.

APPLE II PARALLEL INTERFACE CARD

John Bell Engineering is announcing an Apple ilParallel Interface Card. There are four I/O ports withhandshaking logic.The board has two 6522 versatileinterface adapters and a 74LS74 for addressing andtiming. Each 6522 has two interval timers. This will in-terface your Apple II to printers, speech synthesizers,keyboards, and other John Bell Engineering products.Inputs and outputs are TTL and CMOS compatible.Prices:

79-295 Complete kit $69.95

79-295 Assembled $79.95

SOLID STATE SWITCH

Now you can control the World! Switch lights on andoff for home security, computer controlled disco lightshows. Turn your printer on only when needed. TheSwitch can handle 720 watts (120 VAC 6 AMPS). Its in-put is TTL compatible (5V-2MA), isolation 1500VDC.The circuit board is 2" square on the one channel kitand 2"x 8" on the 4 channel unit.Prices:

t Channel kit $9.95 assm. $12.50

4 Channel kit $34.95 assm. $44.95

A to D D to A CONVERTER

John Bell Engineering now has available an Analog toDigital and Digital to Analog Converter Board. Featueslow cost medium speed (50,000 conversions persecond) for applications such as speech recording andmusic synthesizing. Single power ( + 5) required.Parallel Inputs and outputs Include 8 data bits, strobelines, and latches. Analog inputs and outputs aremedium Impedance zero to live volt range.Prices:

79-287 Kit $49.95

79-287 Assembled $69.95

PRODUCTS AVAILABLE FROM:

JOHN BELL ENGINEERING

P.O. BOX 338

DEPT. 4

REDWOOD CITY, CA 94064(415)367-1137

J B ENGINEERING

SOPmicrosystems

There is nothing like a

Dflim

A complete disk system for the Rockwell Aim 65. Usesthe Rockwell Expansion Motherboard. Base price of$850 (U.S.) includes controller with software in Eprom,disk power supply and one packaged Shugart SA400Drive.

224 SE 16th St.P.O. BOX687

AMES, IA 50010(515) 232-8187

At first it appears to tie an IBMSelectric™. It is! A standard keyboard,familiar operation that does such agood job on day-to-day typing. Look,closer. There are extra controls: CON-TROL ESCAPE DELETE REPEATABORT TEST. The full functions of acommunications terminal. It is! Con-nect the cable to your system'sRSS32C connector and quick as ablink you can communicate. Inputand receive? That's right. It's aprinter, too. And, what a printer!Sharp, neat, clear impressions. IBM

* • ; - :TTi»

Western I/O 7750 E. Redfield

Selectric,M quality, whether typed by hand or by your computer. Typewriteryes, communicator yes, printer yes. All three beautifully packaged in asingle machine for $1595.

Buy one, today, and expand your present system with the flick of aswitch. In the blink of an eye.

Western I/O

K

■ •|11i"l""ttiHinii:

ft y'gggggpllt

Road Scottsdale, Arizona 85260 Area Code (602) 948-3162

Circle 197 on inquiry card.

BYTE May 1980 263

DO|Z>

di o-

DZ[>

03 O

D4[Z>-

D5|Z>-

D6|Z>-

D7[>

F0[>

F'C^

F2[>

F3(Z>-

/77

C ICI474154

IC974B6

1CII7404

ti

ICI37420

A

TA

3) '°c^x

ICIO7486

b\ ICI2

-O>D0

-Odi

-O D2-0>D3-0> D4

■O 05

O06

-C>D7

MULTIPLE■O BIT

ERROR

Figure 7c: Schematic diagram of the circuit which corrects single-bit errors trapped by the circuit of figure 7b. Multiple-bit errors aremade known to the processor, but cannot be corrected using this scheme.

u

Everything should be as simple as possible,

but no simpler"

Einstein

LvR. L/OBB'S JOURNAL (Software and systems for small computers)

P. O. Box E, Dept. H8, Menlo Park, CA 94025 ' $15 for 10 issues ' Send us your name, address and zip. We 'II bill you.

264 May 1980 © BYTE Publications Inc

Circle 198 on inquiry card.

Circle 199 on inquiry card.

Circle 200 on inquiry card.

TERMINALS

FROM TRANSNET

PURCHASE FULL OWNERSHIP AND LEASE PLANS

PURCHASE PER MONTH DESCRIPTION PRICE 12H0S, 24 MPS. 36 MPS.

LA36 DECwriter II $1,695 $162 $90 $61

LA34 DECwriter IV 1,295 124 69 47

LA120 DECwriter III KSR ... 2,495 239 140 90

LA180 DECprinter I 2,095 200 117 75

VT100 CRT DECscope 1,895 182 101 68

VT132 CRT DECscope 2,295 220 122 83

DT80/1 DATAMEDIA CRT .... 1,895 182 101 68

TI745 Portable Terminal .... 1,595 153 85 57

TI765 Bubble Memory Terminal 2,795 268 149 101

TI810 R0 Printer 1,895 182 101 68

TI820 KSR Printer 2,195 210 117 79

TI825 KSR Printer 1,695 162 90 61

ADM3A CRT Terminal 875 84 47 32

QUME Letter Quality KSR ... 3,195 306 170 115

QUME Letter Quality RO .... 2,795 268 149 101

HAZELTINE 1410 CRT 875 84 47 32

HAZELTINE 1500 CRT 1,195 115 64 43

HAZELTINE 1552 CRT 1,295 124 69 47

Dataproducts 2230 Printer .. 7,900 757 421 284

DATAMATE Mini Floppy 1,750 168 93 63

FULL PWNERSHIP AFTER 12 PR 24 MONTHS • 10% PURCHASE PPTIPN AFTER 36 MPNTHS

ACCESSORIES AND PERIPHERAL EQUIPMENT

ACOUSTIC COUPLERS* MODEMS • THERMAL PAPERRIBBONS • INTERFACE MODULES • FLOPPY DISK UNITSPROMPT DELIVERY • EFFICIENT SERVICE

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201-688-7800

TWX 710-985-5485

CONTROL THE WORLDTHROUGH A EIA RS-232C PORT

:c •-

■

ALI has designed a new control system that uses a standard serial port to communicate to over1000 output points and read dver 1000 input points With this syslem you can now control relays,lights, motors. 0/A. and sense photo eyes, voltage, switches. A/D. keyboards and a lot more. Allthis control over a single RS-232C link' All it takes is a standard RS-232C port and one or more ALIcontrol modules, per your I/O requirement Up to 225 modules can be connected to a single EIARS-232C port.

The modules consist ol an I/O CONTROL COMMANDER by itself or in conjunction with one of thespecific I/O interface boards. Each I/O CONTROL COMMANDER has 8 TTL inputs and 4 TTL out-puts, plus all ol the circuitry necessary lor proper address decoding and communications liming.Each CONTROL COMMANDER is crystal controlled lor highest accuracy and reliability. Baud rate isselectable from 150 to 9600 baud.Various peripherals can be plugged into the I/O CONTROL COMMANDER to handle specific I/O

functions.

ASSM

$149

KIT

$129

I/O CONTROL COMMANDER

• 8 TTL inputs

• 4 TTL outputs

• 150 to 9600 Baud

• Crystal controlledRELAY INTERFACE 120

• 4 2A, 120V AC relay outputs

• 4 5V-120V AC or DC opto-isolated inputsUNIVERSAL I/O, KEYBOARD DISPLAY INTERFACE 190

• Up to 16 character display

• Up to 32 digits display

• Up to 64 individual inputs

• Sense full ASCII keyboard

• Up to 128 individual outputsALPHA NUMERIC DISPLAY 179

• 16 Alpha numeric displays

• Mates with UVKDTHUMBWHEEL SWITCH UNIT 165

• 8 Digits BCD inputs

• 32 Bits TTL input

• Mates with UVKD

As you can see from the above description, you can mix and match modules to meet your specificrequirements All this and more over a single RS-232C link The above is only a briel summary ofthe available options.TO ORDER CALL OR WRITE:

AL INDUSTRIES

15 Algonquin Trail, Oakland, N.J. 07436

(201) 337-2030'N J Residents add 5% sales lax • Dealers Inquiries Invited

98

152

155

145

PL

m

INFINITE BASIC

For MOD I TRS-80™ Tape and Disk Systems

Extensions to Level II and Disk BASIC $49.95

Full MATRIX Functions — 30 BASIC commands!!

Mathematical and common matrix functions. Change arrays in

mid-program. Complete array handling. Tape array read and write,

including strings. Common subroutine calls.

Over 50 more STRING Functions as BASIC commands!! String

manipulation, translation, compression, copying, search, screen

control, pointer manipulation and utility functions. Includes

multikey multivariable machine language sorts. Load only machine

language functions that you want! Where you want in memory!

Relocating linking loader! More than you ever expected!!

oo BUSINESS (Requires Infinite BASIC) $29.95

20 Business oriented functions including:

Printer Automatic Pagination with headers and footers!

Packed Decimal Arithmetic ( + ,-,*,/) 127 digits!

Binary array searches and hash code generator!

COMPROC Command Processor for Disk Systems $19.95

Auto your disk to perform any sequence of DOS commands,

machine language loads, BASIC, memory size, run program,

respond to input statements, etc. Single BASIC command file

defines execution! Includes auto key-debounce, screen print and

lower case software driver.

REMODEL + PROLOAD Specify 16, 32, or 48K Memory $34.95

REnumber any portion or all of BASIC program. MOve any portion

of program from one location to another. DELete program lines.

MERGE all or any portion from tape. Save and verify portion or

all of combined merged programs to tape.

GSF (Specify 16, 32, or 48K) $24.95

18 Machine language routines. Includes RACET sorts.

CHECK, VISA, M/C, C.O.D. DEALER INQUIRIES INVITED

Calif. Residents add 6% WHEn ordering please

Telephone Orders Accepted (714) 637-5016 advise publication source

TRS-80 IS A REGISTERED TRADEMARK OF TANDY CORPORATION

DISK SORT MERGE %DSM'

For MOD I and MOD II TRS-80™

Now you can sort an 85K disketteFAST — jn less than 3 minutes* - FAST

Perfect for your multi-diskette RANDOM file mailing lists, inven-tory, etc. Ideal for specialized report generation. Sort, merge orcombination. All machine language stand-alone package —Efficient and easy to use. No separate key files required! Physicalrecords are rearranged on diskette! Supports multiple sub recordsper sector including optional sector spanning. Sorts on one ormore fields — ascending or descending. Sort fields within recordsmay be character, integer, and floating-point binary. Providesoptional output field deletion, rearrangement, and padding."Sort timings shown below are nominal times. Times will varybased on sort and system configurations. Nominal times basedon Mod I 48K 4-drive configuration, 64 byte records, and 5 sort keys.

TYPE FILE SIZE SORT TIME

(Bytes)

(Sec)

SORT

16K

33

SORT

SORT

32K

49

SORT

SORT

85K

173

SORT and

SORT

170K

445

MERGE

TYPE

FILE SIZE(Bytes)

340K

680 K

85KSORT +

1275K Merge

DSM for Mod I (Minimum 32K, 2-drives) $75 On-DiskDSM for Mod II (Minimum 64K, 1-drive) $150 On-DiskMod II Development Package $100

Machine Language SUPERZAP, plus Editor/Assembler

Disassembler patches.Mod II Generalized Subroutine Facility 'GSF' $50

SORT TIME(Sec)108125691757

and

|r- RACET computes -^

702 Pilmdile, Onnge CA 92665

Circle 201 on inquiry card.

BYTE May 1980 265

SAVE

ON ADD-ONPRODUCTS FOR

TRS-80

The largest family

of disk drives from

the largest supplier,

drives come

complete with

power supply and

cabinet.

TF-Pertec FD200, 40 track, use both sides $389

TF-3 Shugart SA400. 35 track, same as tandy $389

TF-5 MPI B51. 40 track , $389

TF-70 Micropolis, 77 track with 195K of storage $639

TDH-1 Dual sided drive. 35 track $499

....WXKflvori ftAOOO

$5349$695

77 tra

Max,D,sk HO Megabyte Hard Disk w„h 5.,xed,5 removable with controller

Maxi Disk 2: 10 Megabyte (fixed)Winchester Technology

cks of Storage includes new DOS ■

PRINTERS

DP800 Anadex, 80 column, 112cps $950

LP779 Centronics 779 $1069

LP730 Centronics 730 $950

LP700 Centronics 700-1 $1495

LP701 Centronics 701-1 $1759

LP702 Centronics702-2 $1995

SPW-1 Spinwriter-NEC $2599

Fault Code

Error

0000

no error detected

0001

check bit 0

0010

check bit 1

0011

data bit 0

0100

check bit 2 *

0101

data bit 1

0110

data bit 3

0111

data bit 6

1000

check bit 3

1001

data bit 2

1010

data bit 4

1011

all data and parity set to logic 0

1100

data bit 5

1101

multi bit error

1110

data bit 7

1111

multi bit error

Table 6: Look-up

table

of fault codes used by the 8-bit to

12-bit encoding sc

heme

Setting of the check-bit-2 fault code

(indicated by an asteris

<) shows that all data and parity bits

are set to logic 1.

NEW! LINE PRINTER

BASE 2

Base 2 Printer 80. 132 col, graphK60 LPM with tractors.

$649

* DRIVES FOR ANY MICROCOMPUTER *

Does not include power supply & cabinet.MOD II DISK DRIVES NOW AVAILABLE

Perfec FD200 $282

Perfec FD250 (dual head) $399

Shugart SA400 (unused) $286

Shugart SA800 $479

MPI B51 $279

MPI 852 $349

SOFTWARE

New DOSf with over 200 modifications and

corrections to TRS-DOS $99

New DOS' 40 track $110

AJA Word Processor $75

AJA Business Program $250

Racet Infinite Basic $49.95

Disk Drive Alignment Program $109

Radix Data Base Program $99.95

Electric Pencil $150

ALL PRICES CASH DISCOUNTED. FREIGHT FOB/FACTORY1 T I /MICROCO/MPUTER /A\

flJI^Sg^H) c=W\pparat, Inc.

Circle 329 on inquiry card. Circle 202 on inquiry card.

3304 W. MacArthur 7310 E. Princeton Ave.

Santa Ana, CA 92704 Denver, CO 80222

(714) 979-9923 (303) 758-7275

"See us at NCC,booth 69"

266 May 1980 © BYTE Publications Ire

Check Bit

Data Positions

01234

2,5,10,11,12,13,14,15 (odd)4,5,6,7,8,9,10,15 (even)1,2,3,7,8,9,14,15 (odd)0,2,3,5,6,9,12,13 (even)0,1,3,4,6,8,11,13 (odd)

Table 7: The 16-bit encoding scheme uses 5 parity bits thatenable single-bit error correction. Each parity-check bit per-

forms its check operathere.

on upon the data-bit positions shown

Fault Code

Error

00000

no error detected

00001

error in check bit 4

00010

error in check bit 3

00011

error in data bit 0

00100

error in check bit 2

00101

error in data bit 1

00110

multiple-bit error

00111

error in data bit 3

01000

error in check bit 1

01001

error in data bit 4

01010

all data and parity set to logic 1

01011

error in data bit 6

01100

error in data bit 7

01101

error in data bit 8

01110

error in data bit 9

01111

multiple-bit error

10000

error in check bit 0

10001

error in data bit 11

10010

error in data bit 12

10011

error in data bit 13

10100

error in data bit 14

10101

all data and parity set to logic 0

10110

error in data bit 2

10111

multiple-bit error

11000

error in data bit 10

11001

multiple-bit error

11010

error in data bit 5

11011

multiple-bit error

11100

error in data bit 15

11101

multiple-bit error

11110

multiple-bit error

11111

multiple-bit error

Table 8: Look-up table

of fault codes used by the 16-bit to

21-bit encoding scheme.

The codes are shown here in order

from check bit 00 to bit 04, reversed from the representation

in figure 6.

Circle 203 on inquiry card.

Data Output

Address Input

7 6 5

4 3 2 10

00000

0 0 0

10 0 0 0

00001

0 1 0

10 0 0 0

00010

0 1 0

10 0 0 0

00011

0 0 0

0 0 0 0 0

00100

0 1 0

10 0 0 0

00101

0 0 0

0 0 0 0 1

00110

0 0 1

10 0 0 0

00111

0 0 0

0 0 0 11

01000

0 1 0

10 0 0 0

01001

0 0 0

0 0 10 0

01010

1 1 0

10 0 0 0

01011

0 0 0

0 0 110

01100

0 0 0

0 0 111

01101

0 0 0

0 10 0 0

01110

0 0 0

0 10 0 1

01111

0 0 1

10 0 0 0

10000

0 1 0

10 0 0 0

10001

0 0 0

0 10 11

10010

0 0 0

0 110 0

10011

0 0 0

0 110 1

10100

0 0 0

0 1110

10101

1 0 1

10 0 0 0

10110

0 0 0

0 0 0 10

10111

0 0 1

10 0 0 0

11000

0 0 0

0 10 10

11001

0 0 1

10 0 0 0

11010

0 0 0

0 0 10 1

11011

0 0 1

10 0 0 0

11100

0 0 0

0 1111

11101

0 0 1

10 0 0 0

11110

0 0 1

10 0 0 0

11111

0 0 1

10 0 0 0

Table 9: Truth table which is

programmed into a program-

mable read-only memory for

use in the

electronic circuit of

the 16-bit error-checking and

correcting system.

Number

Type

+ 5 V

GND

IC1

74180

14

7

IC2

74180

14

7

IC3

74180

14

7

IC4

74180

14

7

IC5

74180

14

7

IC6

74180

14

7

IC7

74180

14

7

IC8

74180

14

7

IC9

7486

14

7

IC10

7486

14

7

IC11

7404

14

7

IC12

7404

14

7

IC13

7420

14

7

IC14

74154

24

12

IC15

74180

14

7

IC16

74180

14

7

1C17

74180

14

7

IC18

74180

14

7

IC19

74180

14

7

IC20

7404

14

7

IC21

74180

14

7

IC22

74180

14

7

IC23

74180

14

7

IC24

74180

14

7

IC25

74180

14

7

IC26

7488

16

8

IC27

74154

24

12

IC28

7404

14

7

IC29

7404

14

7

IC30

7404

14

7

IC31

7486

14

7

IC32

7486

14

7

1C33

7486

14

7

IC34

7486

14

7

Table 10

Power supply connections for integrated

circuits

used in e

ectronic logic described

in this article.

VEDIT CPM

Visual Editor

Now Edit 5 to 10 Times Faster

in Word Processing, C-Basic,

Fortran, Assembler and more.

VEDIT is a customizablescreen-oriented editorwhich ends tedious editingof C-Basic, Word Process-ing, Fortran, Assembler andother text files. No longerwill you have to retype longlines, and cumbersomecommands and editingerrors become a thing ofthe past. You simply movethe cursor to any place inthe file and make necessarychanges by typing new textor hitting a function key.VEDIT provides a full arrayof easy to use cursor move-ments, including zip to theend of line. Function keysallow for character deletion,line deletion, and lines tobe concatinated or split.For full flexibility, thenormal set of EDcommands is included, plusmacros with imbeddedvisual mode and text move.

Special Features: Includedis a setup program which

allows you to customizeVEDIT to your screen char-acteristics and keyboardlayout. You decide whichkey or control code to usefor each cursor movementor visual function. Tab keyallows insertion of tab char-acter or spaces to settabletab positions. Lines longerthan the screen are elo-quently handled by writingthem on multiple screenlines and indicating in thefirst reserved column thosethat are continuation lines.Continuation lines are auto-matically created asnecessary while you type.Sophisticated disk buffer-ing can do automaticREAD and WRITE com-mands for files larger thanthe available main memoryspace. Good program doc-umentation is encouragedbecause now all editingbecomes natural and easy.

Availability: VEDIT is available immediately for CP/MSystems with any memory mapped displays, including theVDM, SSM or Matrox boards, or Piiceon I/O mapped dis-play board. Please call or write on availability for VDM8024 (May), smart CRT terminals, Sorcerer (May) and theTRS-80 (June).

Ordering: Specify memory or I/O mapped, 8080/Z80 orZ80 code versions. All packages include 8" disk, VEDITS(all features of VEDIT except regular ED-like commands),customization program and documentation on disk.

Standard Package: Disk with VEDIT & manual $ 100

Deluxe Package: All versions ofVEDIT& manual .... $130

Budget Package: VEDITS only, no manual $75

Manual $15

5% discount for money orders, certified checks. Mich-igan residents ad 4% sales tax. Visa and Master Chargewelcomed.

Dealer Inquiries Invited

'CP/M is a trademark of Digital Research Corp.' TRS-B0 is a trademark of Tandy Corporation.

CompuViewProducts Inc.

1531 JONES DRIVE • ANN ARBOR, MICHIGAN 48105CALL ANYTIME: (313) 996-1299

May 1980 © BYTE Publications lnc 267

Circle 204 on inquiry card.

AVAILABLE

PRESCRIPTION!

THE ONLYSYSTEM OF ITS

KIND YOUR

MICROCOMPUTER

WILL EVER

NEED!

GLOBAL"

DATABASE

MANAGEMENT

SYSTEM

for

PROGRAMMERS, ACCOUNTANTS, BOOK-KEEPERS, DOCTORS, LAWYERS, PUB-LISHERS, SCIENTISTS, MANUFAC-TURERS, WHOLESALERS, RETAILERS,MANAGERS, LANDLORDS, REAL ESTATEAGENTS, TEACHERS, STUDENTS, ETC.

Extremely comprehensive, versatileuser-oriented management system fordatabase creation and list main-tenance. Runs under CP/M* andCBASIC2** on a microcomputersystem in only 40K RAM.Completely user-defined file structurewith sequential, random and linked filemaintenance; user-defined number offields; data transfer between records;automatic high speed searchalgorithms with global search func-tion; built-in ISAM; fast sort/mergeutility; record selectable output can beformatted (with/without headings, col-umn titles, totals, etc.) and printed onvarious forms (labels, envelopes,preprinted forms, etc.); links to CP/Mcommands or programs withautomatic return to Global; providesstatus reports on diskette, data file andhardware environment; disk used asextended memory.

Supplied on standard 8" IBM disk (inquire aboutother formats), complete with BASIC subroutinelibrary in source code, with t/>/\i"comprehensive manual ^/Q^

MANUAL ONLY...$25

Shipping $2.00

C.O.D. 1.00

Sales Tax

where applicable

'Trademark 0/Digital Research'' Trademark otSoftware Systems

DEALER INQUIRIES INVITED

{+ LOBAL

■ ARAMETERS

1505 Ocean Ave., Brooklyn, N.Y. 11230212/252-5002

PJrO'JiO^NOJffi

N |4 V n

W rfl 1

0000000000000000 0_0_0_a.Q-

00000000000000000000

Ogg6gg6gggg6gggg ?

O — CM ro

CT>5

UJQ.

LUQ.

Bo.

UJQ.

1- >z

- Ld_

Qzo —

Figure 8a: Schematic diagram of the circuit to encode 16-bit data into 21-bit words con-taining 5 parity bits.

268 May 1980 © BYTE Publications Inc

Circle 205 on inquiry card.

Circle 206 on inquiry card.

Graphics II™ converts yourDECwriter® to a plotter...... and a whole lot more!!

Vector graphics (automatic

line generator)

1320 X 792 dots per page

Bi-directional line feed• Multiple character sets

(includes APL)

Variable character styles

Multiple interfaces

including RS232■ Prints at 40 Characters/

second

Communicate up to

1200 BAUD

1000 character buffer

with x-on/x-off

Easy to install & plug

compatible

No mechanical changes

required

Raster graphics option

Software option

Time share compatibility

Graphics II for the DECwriter II does everythingyour old DECwriter did . . . and a whole lot more!!

^^ Call or write today for more information

%J^ SELANAR Corporation (408) 727-2811

k 2403 De La Cruz Blvd. Santa Clara, CA 95050

DECwriter is a registered trademark of Digital Equipment Corporation

*$*

HE)!

SOFTWARE

FOR MECHANICAL ENGINEERS

• PIPE FLEXIBILITY PROGRAM: $6000.OOt with sophisticated preprocessor.

• NEMA/API 617 REPORT PROGRAM: $1500.00-, tsteam turbines,centrifugal compressors allowable reactions.

• PUMP-API 610 REPORT PROGRAM: $1500.00\t pump nozzle allowablereactions.

• PIPE REINFORCEMENT PAD PROGRAM: $2000.00t capacity for multiplecombinations of pressures and temperatures,

• MTO CONTROL PROGRAM: $8000.OOt material takeoff and control for pipe,valves, fittings for E and C companies.

• THIN WALL EXPANSION JOINT PROGRAM: $2500,00',t

• WELDING RESEARCH COUNCIL, BULLETIN 107 PROGRAM:;, i 300 ny ■

curves not included.

• HELICAL SPRING COIL PROGRAM: $1000.00'

• QUOTATION PRICING PROGRAM: $5000.00' develops pricing data forcompany selling items containing many types and sizes, and prepairs finalquotation.

NOTE: Ail programs are in standard Fortran 4.tFor Univac 1108. All documentation $20.00.'For microcomputers.

SUPPORT TECHNOLOGY & PRODUCTS, INC.

P. O. Box 35797

Houston, Texas 77035

(713) 988-6622, Telex 76-2306

Call now for a quotation(312) 733-0497

The 550 BANTAM

from Perkin-Elmer

$799

All the features of theHazeltine 1400 &LSI ADM-3A plus

• Upper/Lower Case

• 7x10 Character Matrix

• White or Black Characters

• Transparent Mode

• Addressable Cursor

• Tab Function

• Backspace Key

• Shiftlock Key

• Print Key

• Integrated Numeric Pad

• Editing Functions

• Extremely Compact:15" W x 19" D x 14" H

• Silent fan-free operation

All productsin stock!

U.S. ROBOTICS, INC

1D35 W. LAKE ST.

CHICAGO, ILL. 6D6D7

LA34DECwriter IV

199

Tabs

132 columns

10, 12, 13.2. 16.5

characters/inch

2. 3. 4. 5, 8 or 12 lines/inch

Optional tractor feed

110 or 300 baud

RS232C/ASCII

Friction feed/up to 15"

wide paper

9x7 dot matrix, impact

printing

Upper/lower case

PENRIL 300/1200MODEM

Originate/Auto-Answer

$799

0-300 or 1200 baud

Bell 212A & 103/113

compatible

1 year warranty

Stand alone

RS232

Full duplex over voice

grade phone lines

FCC certified for direct

connection to phone lines

via RJ11C voice jack

(standard extension

phone jack)

Teletype

Model 43 KSR

$1049

110 or 300 baud

RS232C/ASCII

Pin feed/81/' H x 11" W

paper is perfect for filing

and copying

132 column

Upper/lower case, true

descenders

Dot matrix, impact printing

Connect your TRS-80,

Apple or ANY other

computer to the phone

lines with the...

USR-330

Originate/

Auto-Answer

Modem

$339

FCC certified for directconnection to phone lines viastandard extension phonelack

• 0-300 Baud

• Bell 103/113 compatible

• Stand Alone

• RS232

• 1 Year Warranty

• Crystal Controlled

• Stale of the Art LSI circuitry

• 5 stage active filters

USR-310 OriginateAcoustic Coupler

$159

Circle 207 on inquiry card.

BYTE May 1980 269

O _- Nrt*in<i)N(D(j)

pj to ^f m

0000000000000000

W IO t

00000

00000000000000000000

Q O QOQOQOOOQQQOOOQ_Q_a.Q.Q.

Figure 8b: Schematic diagram of the circuit which traps errors from the encoded 16-bit data. Five error-detecting bits are sent to theerror-correcting circuit of figure 8c.

270 May 1980 © BYTE Publications Inc

Circle 208 on inquiry card.

Circle 209 on inquiry card.

S-100, 6-PORT COMMUNICATIONS

WWi I

"ll) iff/7"' '"

• INTERFACES MULTI TERMINALS, COMPUTERS,PRINTERS, MODEMS, ETC.

• 2, 4, OR 6 CHANNELS; 2 OPTIONAL RTC'S

• SELECTABLE I/O ADDRESS

• PROGRAMMABLE SYNC. CHARACTERS

• SYNC AND ASYNC

• HARDWARE ERROR CHECKING (CRC-16, CCITT)

• COMPLIES WITH: EIA RS-232C STANDARD; IEEEPROPOSED S-100 BUS STANDARD

FULL 6-PORT CONFIGURATION (ASSEMBLED ANDTESTED) $895.00

For information, contact: Dianne Polk (703) 893-4330 x 100

Inco, Inc.

7916 Westpark Drive I: McLean. Virginia 22102

Niiuri

Here's $395 worth of convenience for anyone'working with digital systems. Carry itanywhere in a pocket, valise or toolkit to enter___ and retrieve data, run diagnostics, changeconstants, test aata links, etc.

Look at its facilities:

• Transmits 128ASCII codes

• Can display last 30characters received

• Displays full64-character ASCIIset on dearie-segment LEDs• 25-line RS232/C

compatible interface•Single 5V supplyrequired at 400mASM^ typical

^■k 0110 or 300 baud^IB[ transmission selectableH| •Parity codes, stop bitssettable to your standard•Obeys bell, cursor anddata format control codesPhone or write us for more details now:

GR ELECTRONICS,

1640 Fifth Street,

Santa Monica, CA 90401.

Telephone: (213) 395-4774.

65-2337 (BT Smedley SNM).

Telex

9*

BUSINESS & PROFESSIONAL SOFTWAREFOR APPLE II

[ i HOME FINANCE PAK I: Complete package $49.95

[~] BUDGET. The (mart nl a comprehensive home finance system. Allows user to define up to 30 budget

items Actual e»penw input cm In- by «- -,-l: i or by automatic reading of CHFCKBO0K II (ties Coils air

automatically sorted and compared with budget. BUDGET ptoduces hnlli monthly actual/bud get/variance

report and a year to date by month summary nl actual ensts. Color graphics display nf mpenses by month

$24.95

Q CHFCKB00K II: This extensive program keeps cnmph'te records of each check/deposit Unique checkentry system allows user to set up common check purpose and recipient categories Upon entry you selectIrnm this pie rielmed menue to minimis keying in a lot nl data Unique names can also he stored fw enmpleteness This system produces rapid access to check liles Check register display incorporates unique up/down scrolling system for the ultimate in flexibility. 40 column printout ol check register Up to 100checks per month storage. Files accessible hy BUDGET program $14.95

[~~]SAVINGS Allows user in keep track ol deposits/withdrawals lor up to 10 savings accounts. Completerecords shown via screen or 30 column printer.. . . .$14.95

' | CREDIT CARD- Keep control ol your cards with this program Organises, stores and displays purchases.

payments and service chaines. Screen nr 40 column piinwi display. Up to 10 separate cards $14 95

ClTHE UNIVERSAL COMPUTING MACHINE: S39.95

A user programmable enmputing system structured around a 15 row by 30 Column tahtr Usei delines rowand column names and equations forming a unique computing machine. Tahln elements can be multiplied,divided, subtracted or added to any other element User can define repeated luuctinns enmmon in a low Olcolumn greatly simplifying table setup. Huudrrd ol uoique computing machines can be defined, used, storedand recalled, with nr without old data, for later use. Excellent fur sales forecasts, engineering design analysis,budgets, inventory lists, income statements, production planning, project cost estimates m short for anyplaining, analysis or reporting problem that can be solved with a table. Unique cutset commands allow youto mnve to any element, change us value and immediately see the effect on other table values Enure lablncan be printed by machine pages (user defined 3 5 cnlumns) un a 40 column printer, Translnrm your com-puter into a UNIVERSAL COMPUTING MACHINE

[ZJCOLOR CALENDAR: HIRES eotoi graphics display of your personal calendar. Automaticmultiple entry nl repetitive events Heview at a glaoce imponanl dates, appointments, anniversaries, birthdays, actioo dales, etc over a 5 year period. Graphic calendar marks dales Printer and screen display asummary report hy month of your lull text desr.iibmg each day's action item or event Ideal for anyone witha busy calendar $19 95

□ MICROACCOUNTANT: ThB ideal

i for

ash bus

Hid un

the small cNile entry bookkeeping, this efficient program records abalances, general ledger journals, revenue and expenses. Screen m 40 column printer reports Handles up to

500 .(..if ri.il entries per period, up to 100 accounts. Program inslructioos include a short pnmer io FinancialAccounting S49.95

HTHE MATHEMATICIAN: Complete package $39.95

utility prugram for computing the determmisional set of linear equations

D PL OTTER 2D Two dimensional plotting of any function

[ 1PL01TER 3D: Three dimensional surface plntting of any 3 variable (unctionHIRES

S14 95

. .S9.95

sing Apple

.$14.88

r~)R0OTS A qeneral purpose program lot numerically finding the solutions to any nonlinear equation.

Uses ipiadiatic interpolation S14.95

SEND FOR FREE CATALOG - All programs run on 32K Apple II with Disc and Applesoft ROM Card, or 48K without ROM Card Detailed instructions included with each ptogram. California residents add 5VK sales lax Send checkor money ordei to:

SPECTRUM SOFTWARE

P.O. BOX 2084 SUNNYVALE. CALIFORNIA 94087

FOR SER/OUS USERS

OF 8080, 8085, OR Z80 COMPUTERS

PRINTER WIZARD - Now add powerful capabilities toyour printer. Free your computer for use whilesimultaneously printing backlogged output on a first-in-first-out basis. Transparent operation without noticableslowing of the computer. Allows continuous computer andprinter operation on programs having sporadic output. Willbacklog up to 100 pages when used with a disk system.Adds optional automatic paging with numbers, adjustablemargins on 4 sides, indented overflow lines. Occupies lessthan 2/2 K.

Documentation only

EX80M103EX80M103D

$45.00$ 7.50

DISASSEMBLER — Disassemble machine code into stan-dard source language. Modify or relocate existing programssuch as DOS or BASIC using your existing assembler (notincluded). Disassembles any 8080, 8085, or Z80 code, in-cluding embedded data blocks and "trick" codes.Generates symbol and label tables.

Documentation only

EX80M217EX80M217D

$75.00$12.50

ALL EXCOM products are fully supported and warranted indefinitely againstoriginal defects. Available on single or double density NORTHSTAR 5'A"diskettes. 300 or 1200 baud cassettes (specify). Washington residents add5.3% tax.

EXCOM

P.O. Box 1802 Bellevue, Washington 98009 U.S.A.Telephone (206) 641-6577

Circle 210 on inquiry card.

Circle 211 on inquiry card.

BYTE May 1980 271

-1 Q= < =>z

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000 0000000000000000

CO ^

C\lO N

to _ (\J

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01 ■*

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-OS

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A A A A A A "A A A A A A""A AAA

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Figure 8c: Schematic diagram of electronic logic that corrects errors in 16-bit data.

272 May 1980 © BYTE Publications Inc

Circle 212 on inquiry card.

Circle 213 on inquiry card.

the electric pencil II

is now availablefor the TRS-80 Model II* Computer

Standard Printer Version $275SERIAL DIABLO, QUME and NEC Printer versions $300

Features

• CP.M COMPATIBLE ONLY

■ Support* [0U( disk rfftvas

• Dynamic print lormiiiiinrj

• DIABLO and NEC printer packages

■ Mutti'tnlunm loimailing in one pass

• Pnni vehia chaining

• Page-iii-.i rime scrolling

• Biilircciirjiidl muiiisptc'd scrolling controls

• Substyfiem wiih prim value scoreboard

• Aulum.ilii; word and record number rally

• Full ntugln control

• Endol pay.- control

• Non-printing text commenting

• Line ai d p.tragrapli Endantatton

• Centering

• Und«l

• Bold I".

ELECTOC '^PENCIL..

The Electric Pencil II is a Character Oriented WordProcessing System. This means thai texi is entered as astring of continuous characters and is manipulated assuch. This allows ihe user enormous freedom and ease in[he movement and handling of text. Since line endingsare never delineated, any number of characters, words,lines or paragraph may he inserted or deleted anywherein the text. The entirety of the text shifts and opens up orcloses as needed in full view of the user The typing ofcarriage returns or word hyphenations is nol requiredsince lines of text are formatted auiomatically.

As text is typed am\ ihe end of the line is reached, apartially completed word is shifted to the beginning of ihefollowing line Whenever text is inserted or deleted.existing text is pushed down or pulled up in a wraparound fashion. Everything appears on ihe video displayas it occurs, which eliminates guesswork. Text may bereviewed at will by variable speed scrolling both in thery -,___ forward and reverse direction. By using

\ the search oi search and replace functnany string of characters may be located

d/or replaced with any other string ofcharacters as desired.

Demand a demo from your dealer!

mss

MICHAEL SHRAYEH SOFTWARE, INC.

1198 Los Rotales Di

PalmSptmgs, CA. 92262

1714) 323-1400

NO FRILLS! NO GIMMICKS! JUST GREAT

DISCOUNTS

MAIL ORDER ONLY

HAZELTINE

1400

S 549.00

1410

750.00

1420

795.00

1500

875.00

15001 Kill

850.00

Mod 1 Edit

1295.00

CENTRONICS Special

700-2 1095.00

Micro Printer 325.00

DECLA34 1075.00

NORTH STAR .

Horizon I assembled

kn

Horizon II assembled

20%Off

XYMEC

HY-Q1000 DaisyPrinter 22*55.00

INTERTECSuperbrain 2595.00

DIGITAL SYSTEMS

Computer $4345.00

Double Density

Dua Drive 2433.00

TELEVIDEO912 775.00

920 850.00

OKI DATASL160 2395.00

CP110 995.00

CROMEMCO

System III S1000off 5990.00TEXAS INSTRUMENTS

1595.00

795.00

CALL

99.95Box/34.95Box/39.95

810 PrinterATARI 800

ADDS Regent 25Optima Cabinets

(New)5" Scotch Diskette8" Scotch Diskette

Most items in stock for immediate delivery. Factoryfresh, sealed cartons.

DATA DISCOUNT CENTER

Box 100 135-53 Northern Blvd., Flushing, New York 11354, 212/465-6609

N.Y.S. residents add appropriate Sales Tax. Shipping FOS N.Y.BankAmericard, Master Charge add 3%. COD orders require 25% deposit.

At last—NETWORKING!

SATELLITE SATELLITE

PRINTER HUB MC

The CDL Network Operating System in your computers willgive you:

SAVINGS One disk and printer can be shared amongany number of satellite computers. Hard and floppy diskversions are available.

POWER All satellites have a full CPM environment.You can access the largest collection of software availablefor microcomputers.

FLEXIBILITY The network software can be adaptedto your input/output hardware. It even adapts automa-tically to available RAM.

The CDL Networking Operating System is a quality soft-ware product with excellent documentation backed byextensive testing.

Write for information.

CAMBRIDGE DEVELOPMENT LAB

44 Brattle Street Cambridge, MA 02138

THE L1SSENCEof output quality

Any IBM SELECTRIC®can be con-verted to produce high quality out-put at an affordable price!

Interfaces directly to SI00, Parallel,RS-232 or IEEE-488.

Compatible with TRS-80, Sorcerer,Pet, Apple, Horizon, etc.

Why be printer bound? Prices from

$496 to $675.

c

Backspace and TabAvailable NOW!

m

Escon Products, Inc.

171 Mayhew Way, Suite 204

Pleasant Hill, Ca., 94523

(415) 935-4590

Circle 214 on inquiry card.

Circle 215 on inquiry card.

BYTE May 1980 273

Text continued from page 262:parallel-to-serial conversion during awrite operation, and a serial-to-parallel conversion during a read pro-

cess. Details of this hardware will de-pend upon the actual data-transferlogic present in existing systems.Locating single errors is accom-

BUS INTERFACE

i—

DATA

CORRECTED

DATA

"1

PARITYGENERATOR

CORRECTINGLOGIC

1

| DATA [ FAULT CODE

TRAP LOGIC

L

DAT

A +

PARITY«

N^

»

DATA + PARITY

J

MASS STORAGE

Figure 9: Block diagram of data flow through the error-checking and correctingsystem. The extra parity bits are never seen by the processor, and make the systemtransparent from the point of view of the system bus.

plished by interpreting the fault codegenerated by the error-detectionlogic. This interpretation is done byuse of an 8-bit by 32-word program-mable read-only memory(8223/7488) which produces a binaryoutput corresponding to the error-bitposition in the data word. Error cor-rection is achieved by loading thebinary pointer into a 4-to-16 linedemultiplexer that flags the proper bitline and corrects the fault with anexclusive-OR inversion. (See figure10.) With an 8-bit system, the incon-venience of programming the read-only memory may be avoided byloading the fault code directly intothe demultiplexer and then "pickingoff" the corresponding output.

Treatment of Multiple Errors

Although single-bit errors are farmore common, multiple failureswithin one data word can and do ap-pear. For all intents and purposes,these are uncorrectable— particularlyin longer data words. Prohibitivelyextensive logic would be required tolocate multiple-fault bits; therefore,these errors are simply trapped tocause a processor interrupt. The

BUILD YOUR COMPUTER BREADBOARDS

& INTERFACES FASTER AND EASIER

WITH NEW VECTOR PLUGBORDS

EASY TO USE! COST EFFECTIVE! CLEAN HOLES!

4610 Series - For STD-BUS-WW, solderable andun patterned models

4608 Series - For Intel/National SBC/BLC 80-WW/solderable, or unpatterned

8804 Series - For SI 00 -5 models available

4607 - For DEC LSI 11/PDP8-11, Heath H-11

4609 - For Apple II,SuperKim, Pet Commo-dore with Expandamem

4350puter

For Tl 980 Com-

PixMSM^m/eGmpani/ m

ICORPORATED

12460 Gladstone Ave., Sylmar, CA 91342 (213) 365-9661 TWX (910) 496-1539

Available through Distributors or Factory Direct if not available locally.

74801

274 May 1980 © BYTE Publications In

Circle 216 on inquiry card.

Circle 217 on inquiry card.

Circle 218 on inquiry card.

CP/M SOFTWARE

Word Processing For CP/M

FMTText Formatter $75

Use FMT and your text editor to convert your CP/M system to apowerful word processor. FMT features include automatic pageheadings and footings, page numbering, centering, underscoring,external file merging, and in-line console input. FMT works with anyvideo, CRT, or hardcopy terminal and printer combination. Addedcapabilities for daisy-wheel printers: superscripting, subscripting, andhalf-line spacing.

Run Cromemco Software Under CP/M

ADAPT Software Interface S50

Now you can get Cromemco software to run on your CP/M system.ADAPT interfaces those powerful Cromemco packages (except for Multi-User BASIC) to any Z-80 based CP/M system without patching. ADAPTworks without changes for any memory size.

Fast RATFOR

RATFOR (RATional FORtranj $95

RATFOR lets you write structured code that translates to Microsoft orCromemco FORTRAN. TSW'S RATFOR |RATional FORtranlprecompiler runs at more than 1000 statements per minute.Documentation includes "Software Tools" book by Kernighan andPlauger. (ADAPT and RATFOR packages combined J125|

THE SOFTWARE WORKS

8369 Vickers

San Diego, CA 92111

(714.) 569-1721

VISA and MutetChuga accepted:p.'M is .i trademark "I ritual Rc.-.ir

TOLL FREE ORDERING

These FineProducts and More

NORTHSTAR

ASM

KIT

TERMINAL

HRZ-1-16K-D

1600.

1275.

SOROCIQ-120

760

HRZ-1-32K-D

1995.

1580.

HAZELTINE1400

760

HRZ-2-32K-D

2300.

1900.

HAZELTINE1500

940

HRZ-1-32K-Q

2300.

1750.

HAZELTINE1510

1050

HRZ-2-32K-Q

2700.

2230.

TELEVIDE0912

700

RAM-16K

365.

325.

TELEVIDEO920

750

RAM-32K

565.

515.

PRINTERS

FPB-AMDS-A-DMDS-A-QEXTRA DRIVE-DEXTRA DRIVE-Q

285.

710.880.

220.

660.830.350.525.

BASE-2

TI-810

CENTRONICS-799

NEC-5510

NEC-5520

4501580

97025502800

HARD DISC SYSTEM CALLMost NorthStar computers comestandard with real wood cover, 2serial ports, 1 parallel port, realtime clock, disc operating systemand NorthStar basic.

SOFTWARE—DISCS—MISC

AUTOSCRIBE 325.

VERBATUMDISCS(10) 28.

5 FOOT RS-232 CABLE 20.

10FOOTRS-232CABLE 25.

WE WILL TRY TO BEAT ANY ADVERTISED PRICE

A. E. I.

4341 W. Commonwealth Ave Suite D

Fullerton, Calif. 92633(714) 739-4701 (800) 854-6003

CHESS

CP/M CP/M

i COM Flltv. Alia included.

Sargon (or CP/M from your Sargon Book assembled and patched to run aa complata ASCII source tils of thn original lait if the booh.

This modified program allows adjourning a game in progress and living to disk for continuation ■( a later limn. Thalilt r,l moves for both tidei is saved and can be lilted Id tha contola or printer for ■ permanent1 garni record. Powerfulnew analysis feiturs allows amine letting up of board positions changing sides or level during e game, or taking heckmovai Terminal non-specific board position display routines. Sargon automatically orients the displayed board so thatthe player's piacai are always toward him for oesa of play. The lait 15 moves ere comtently displayed with the boardposition.

This program ia written in ZSO Aaaemblsr and dons not require any intarpratara. Rum Inae linla as a 20K CP/M System.

All this lor only $24.49!

Custom Graphics Interface, 2x3 cell memory mapped video, such at Vector FW II or IMSAI VI0 end others.Displays board and piacet in chess graphics for an eye-catching diiplay of the game.

Only $39.44 Complete with ell other above teotures.

Specify disk type and format.

Send us your book and i blank ditk and we pay return pomps

If you do not have a boob

Add 11495 and we will provide one.

Add 16 DO aid we provide the diiketta.

California residents add 6% sales tax on book and diskette

ALSO: Personalized Infoaoft IOS Vsralon 2.0. I00S CPIM*. CD0S*, SDOS' Compilable Diskopereting lystem runs with ebsolutely any hardwire now available. Four yeers and thousands of hours of use by80807280 users ell over the country.

APPLE • CENTRONICS • TEXAS INSTRUMENTSHORIZON • VECTOR GRAPHIC • CROMENCO• RADIO SHACK • HPj: < '^gQPOLIS • SOROC

Standard Features I

elude:

1. Multiple disk types running simultaneously (all formats 100% lifeboat compatible)

2. Automatic Print Spooler

3. Complete set ot powerful utilities

4. Inheneed system function cells

5. Fully end-user relocatabloS. File attributes

7. Complete manuals for novice users or iiperionced programmers

Put an end to CPIM hardware specific limitations at last and save money at tha same time with this personaliiad IOSconfiguration service.

$95 Standard Configuration. (We have thousands of standard configurations! nominal charge for custom 110 anddish drivers.

Infosoft IOS Version 3.0

F41 hard disks with improved dynamic directory processing and memory management See Infosoft ad in GYTE.1150 00 configured.

The Old Association

3744 Pescadero Drive

Santa Barbara, Calif. 93105

(805) 682-8587

*TM Digital Research, Cromemco, SO Systems

Circle 219 on inquiry card.

WE'VE GOT YOU COVERED!

Cover Craft Dust Covers protect your hard-ware and your investment. Save mainte-nance, downtime and look great. Our DustCovers come in hundreds of sizes each cus-tom designed to fit a particular model of termi-nal, CPU, Line Printer, Floppy Disk. They're aproven way to help eliminate dust and dirtaccumulation, improve system reliability andsave many times the cost in reduced mainte-nance and downtime. What's more, yoursatisfaction is 100% guaranteed.

Cover Craft Dust Covers are available fromyour local computer retaileror contact Cover Craft.

Can you afford fo wait any longer?

C

COVER CRAFT

P.O. Box 555, Amherst, NH 03031

Telephone (603)889-6811

Circle 220 on inquiry card.

BYTE May 1980 275

loader program can either abort thedata transfer immediately, initiate asecond read attempt from the lastrecord, or display an error messageon the computer terminal promptingdirect operator intervention.

Theoretical Advances

As reviewed by Peterson andWeldon, the Hamming algorithmfalls in the category of cycliccodes. (See reference 3.) In cycliccodes, executing a one-unit right-shift

FAULT

CODE

INPUT

LOGIC STATES

7486

A B

Y

H H

L

H L

H

L H

H

L L

L

Figure 10: Detail of the error-correcting logic. Error correction is achieved by loadinga binary pointer into a 4-to-16 line demultiplexer that flags the proper bit line andcorrects the fault with an exclusive-OR inversion. Eight-bit systems may load the faultcode directly into the demultiplexer and avoid the use of a read-only memory.

PASCAL/M"

A CP/M* COMPATIBLE PRODUCT

PASCAL/M is an Implementa-tion ot the Standard Pascalprogramming language de-signed by Nlklaus Wlrth.

PASCAL/M does all Input/output and file manipulation via calls toCP/M. The file interface intrinsics were chosen to promote Pascalprogram transportability and to provide a bridge between CP/Mand the Standard Pascal language definition. In selecting anddefining extensions to PASCAL/M, heavy weight was given to com-patibility with other existing Pascal implementations. Over 45 ex-tensions to Standard Pascal support:

• Console Cursor Controls • Segment procedures

• Type String • Random access files

Untyped files

Runtime debug support

Otherwise clause onCase statement

PASCAL/M provides single precision floating point (Type Real). Both integer(16 bit) and long integer (32 bit, 9 digit) arithmetic are supported, An op-tional version will support the 9511A math chip. COMING SOON:PASCAL/M FOR THE 8086/88.

f

AVAILABLE VERSIO

N

MS 1

CP/M Type CPU Type

Disk Size

1.4 8080/85

8"

1.4 280

8"

Cromemco

CDOS ZBO

8"

Northstar 2D Z80

5)4-

Superbrain Z80

5'/.~

2.2 8080/85

8"

2.2 Z80

8"

MP/M- 1.1 B080/85

8"

MP/M 1.1 ZBO

8"

TfcSMobJE *80

8"

#'l5

s!

276 May 1980 © BYTE Publications Inc

PASCAL/M requires 56K RAM and orielfloppy disk. The cost is SSSQ. ^FoJmanual only-JS£^ Add $10. outside IheUSA. VISA/MC H (Q

PASCAL/M is a trademaik ol Sorcim

*CP/M & MP/M ate trademarks of Digilal Research

DigitalMarketing

2670 Cherry LaneWalnut Creek, CA 94596

1415)938-2880

operation on any symbol in the com-plete code set will produce a binarybit pattern identical to that of one ofthe other members of the code set.Since Hamming's initial publication,an extensive array of cyclic codes hasbeen derived. Perhaps the best knownare the Bose-Chaudhuri-Hocquenghem (BCH) codes, whichare related to the Hammingalgorithm.

The BCH codes actually represent ageneralized expansion that is par-ticularly suited to coping withmultiple-bit errors. None of thesenewer solutions offer major advan-tage over the basic Hamming checkwhen correcting an 8-bit data word.Several mathematical difficulties areencountered when attempting toderive more effective encoding pro-cedures. Not only is word lengthrelatively short in these systems, butit can be shown that code redundancyoverhead can be minimized to atolerable level in only a small numberof cases.

The alternative method, which isnot unreasonable, would be to en-code and decode entire data blocks,as opposed to individual data words.This would take advantage of the in-creased coding efficiency found forthe longer codes, but would probablyrequire a software implementation tominimize hardware design and ex-pense. Such an approach would cer-tainly increase system reliability, butit would defeat the purpose of in-creasing the speed and efficiency ofdata transfer to and from massstorage, since the processor wouldspend considerable time encoding anddecoding the parity and data blocksbefore and after each data transfer.fi

References. Hamming, R W, "Error Detecting andError Correcting Codes," Bell SystemTechnical Journal, Volume 26 Number 2pages 147 thru 160, American Telephoneand Telegraph Company, 1950.West, J T, "Product Development Profile:Data General Corporation," ElectronicsVolume 48 Number 23 pages 130 thru136, November 13, 1975.Peterson, W Wesley and E J Weldon Jr,Error-Correcting Codes, Second Edition,MIT Press, Cambridge 1972.Sellers, F, Hsiao, M Bearnson, L, ErrorDetecting Logic for Digital Computers,IBM Corporation Systems DevelopmentDivision, McGraw-Hill.

Circle 221 on inquiry card.

Circle 222 on inquiry card.

Circle 223 on inquiry card.

General Ledger

Payroll

Accounts Receivable & payable

Flexible and sophisticated business software that isamong the highest quality on the market. Originallydeveloped by OSBORNE & ASSOCIATES and rapidly becom-ing a standard. Our service is support. We will send youthese programs with the proper I/O and CRT specificsubroutines for your hardware configuration. Get back tobusiness and leave the programming to us. Include hard-ware description with order.

• Accounts Receivable and Payable 145.00

• Payroll (California) 145.00

• Non California state tax calculations

(please inquire) 15-250.00

• General Ledger 145.00

• Multiple profit center option for G/L 25.00

• Manuals (each) 20.00

All programs in CBASIC under CP/M (includes source)UTILITIES

• DOS MOVER for NORTH STAR. Moves DOS and BASICanywhere you want it. (i.e., from 2A00 to 0000) 35.00

• ALS-8 MOVER on North Star Disk 35.00

Synergetic Computer Products

508 University Ave • Palo Alto, CA 94301

(415) 328-5391

Visa • Mastercharge • COD • Certified Check

CP/M is a trademark of Digital Research

S.C. Digital Proudly Introducing"UNISELECT" Model 16KUS

u i ■ | y

■iiiiMNunfmrmniNfiiiinl

16K Static Memory (Ram) withUniversal Bank Select

Introductory Price: $255

with 250 nsec memory chipsAssembled, Tested, and Guaranteed.

Featuring:

S-100 Compatible - Meets IEEE-S100 standard.

Fully Static - 4045 or 21 14, No DMA restrictions.

Addressing - Dip switch addressing in 1 6K blocks.

Bank Select- Port and bits dip switch selectable. Compati-ble with Alph Micro, Cromemco, Marinchips, NorthStar, etc.

Phantom - Built in memory disable via Phantom line.

Quality - Fully socketed, silk legend, solder masks, goldcontacts.

Orders - MC, Visa or COD ($4 handling charges for COD) orPersonal check. Shipping from stocks to 2 weeks.Illinois residents add 5.25% sales tax.

S.C. Digital

P.O. Box 906 Phone:

Aurora. IL 60507 (312)897-7749

unioch the

microcomputer

Engineering Software for TRS-80 Mods I &II

• Air Cond. Com. Cooling/Heating Load

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• Word Processing for Spec Writing

• Lighting Design . Energy |nvest.

• Air Duct Design

• Accounting

• Surveying

• Solar F-Chart& Econ. Analysis

Fire SprinklerSystem DesignLife CycleCost Analysis

Econ. Anal. (June)

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Pipe Design

Electrical Fault

Current (June)

Selected programs also available for other microcomputers

Please tell me more about your engineering programs.

Name

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CATCH THES-100 INC.BUS!

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SSM CB-2 Z-80 CPU Kit

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Godbout Econoram VII A-24K4MHz Memory "Unkit"

S.D. Systems Expandoram 64KMemory Board Kit w/o RAM

Shugart SA400 Double DensityBare Drive

Subject to Available Quantities • Prices Quoted Include Cash DiscountsShipping & Insurance Extra.

We carry all major lines such as

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Circle 224 on inquiry card.

Circle 225 on inquiry card.

BYTE May 1980 277

Circle 226 on inquiry card.

Circle 227 on inquiry card.

Use x,y Genesis

Applesoft Subroutines forApple II graphs

With x,y Genesis you'll have:

smaller programsshorter programming timesubroutines useful in any programperiodic news on tips & applicationsa professional productAt only $74.95Contact:

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(919) 489-7486

Ask about our new business statistics software.

VULCAN = DBMS

THE PROFESSIONAL and PERSONALDATABASE MANAGEMENT SYSTEM

For 8080/Z80 systems under CP/M® or PTDOS

* VULCAN is a complete database management system that has38 powerful, easy to learn, English-like commands tomanipulate files, records, fields, and scratch-pad variables.

* VULCAN has a command repertoire which includes such com-mands as: SORT, REPORT, APPEND, INSERT, EDIT,COPY, REPLACE, LOCATE, DISPLAY, DO, LIST, andLOOP.

* VULCAN JR. is an interactive inquiry/response system whileVULCAN can be used in interactive or program mode. Theprogram mode uses modern structured command programs tocombine powerful DBMS operations.

* VULCAN is written in assembly language for efficient infor-mation processing and requires 36K bytes CP/M® system andone or more disk drives.

* VULCAN can accept or store data in standard ASCII files tobe compatible with BASIC, FORTRAN, word processors, etc.

* VULCAN can be used for mail lists, inventory, accountingsystems, parts lists, etc. It puts you in fingertip control of yourdata. With VULCAN, you don't need to write a program to dosomething out of the ordinary.

•VULCAN (CP/M® or PTDOS) $490

•VULCAN JR. (CP/M® only) $ 98

Manual only $ 25

SCDP

Software Consultation Designand Production

6542 Greeley St.Tujunga, CA 91042 (213) 352-7701

California residents add 6% sales tax.CP/M11' is a registered trademark of Digital Research

DATADISKSYSTEMS

PROFESSIONAL SOFTWARE FOR NORTH STAR SYSTEMS

DIGITAL RESEARCH

CP/M'2.0 — Digital Research's latest disk operating.system tor B08Q/8085/Z80 based microcomputers,now specially tailored (or the North Star disk systems.Includes ED text editor, DDT debugger, ASMassembler, additional utility programs and completedocumentation. CP/M 2.0 is upward compatible withearlier releases and makes a wealth of professionalsoftware available to your system t$150/S25

TEX - A powerful text formatter. Produces finishedcopy with automatic page numbering, led and rightmargin justification, indentation, page headers, linecentering and other quality features. Output may bevectored to printer, disk or console 570/515

MAC — 8080 Macro assembler. Allows use of libraryprograms, greatly increasing programmingefficiency. Uses Intel macro conventions. Assemblytoggles allow listing, hex and symbol table outputs tobo directed to disk, printer, console or combination. Atremendous development aid S85/S15

SID — Symbolic Instruction Debugger lor the 8080.Allows multiple break points with user set passcounter. Displays user labels during debugging whenused with MAC. Greatly reduces hard-copy listingrequirements. Includes back-trace and histogramutilities. A must for serious software development. $85/51S

ZSID — Same as SID except Incorporates completeZ80 instruction set and uses Z-80 mnemonics. 595/515

DESPOOL — Allows simultaneous printing of disk"ifes and user access to other programs. No need tostop production while lengthy printouts are in progress.

$45/$5

SOFTWARE SYSTEMS

CBASIC-2 — A commercially oriented, compiler-interpieter extended disk BASIC. Self documenting,using full length variable labels without penalizingspeed. Compiler permits distribution of softwarewithout releasing source code. 5105/515

California residents add 6% sales tax.Specify single, double or quad capacity.Additional formats available soon.Structured Systems Group programs requireCP/M and CBASIC-2.'CP/M Fa fi rogisiured iradeiiinrh of Digital Research

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BUSINESS SOFTWARE FROMSTRUCTURED SYSTEMS GROUP

GENERAL LEDGER — A comprehensive applicationspackage for business accounting or CPA multi-clientwrite up. Produces financial reports to user definedspecifications. Interactive posting, balance sheet,income statement, general and cash disbursementjournals, sort, multiple profit centers, accountsdistribution and much more. Outstanding package. $895/525

ACCOUNTS RECEIVABLE — A complete open itemor balance forward system. Operates alone, orinterfaces wifh General Ledger. Produces customerstatements, aged trial balance, on-line inquiry, salesreports, reminder notices and more 5695/525

ACCOUNTS PAYABLE - A powerful cashmanagemenl system. Aged account statements,writes checks, cash requirements projection, GeneralLedger update and more included. Stand aloneoperation or interfaces with General Ledger andQSORT 5695/525

NAD — Name and Address System - Stores mailinglists on disk. Prints mailing labels or lists additionalreferences information. Selective data exlraction. $75/510

QSORT — A generalized, lull disk sort/mergepackage. Fast and flexible Multiple key sorting.

595/515

LETTERIGHT — Word processing for the businessoffice. Produces professional correspondence,letters, envelopes, and more. High speed productionwith minimal training Multiple personalized lettersproduced when used with list formed by NAD

5175/520

ANALYST — Generalized data base managementprogram. Stores and retrieves disk data producinguser formatted reports. Interactive input. Easy to use.Tremendous versatility 5225/520

INVENTORY — Complete Inventory control prograilimited in capacity only by your disk size. On-ltrinquiry, average valuation, reorder arid activity report:with report range option. Menu driven and fullyauditahle. the system uses full screen formatting andpermits user defined record numbers. 5795/525

NOW—AN AFFORDABLE HARD DISK

Ask about our 13.2 megabyte Winchester technology!hard disk business system. Uses all above listed |software. Price varies with software configuraiion.

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INTRODUCING THENEW STATE-OF-THE-ARTIN MICROCOMPUTERSOFTWARE.

Call or write today for ourfree catalog.

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5835 Grand Ave. • P.O. Box 4865Des Moines, IA 50304 • 515/279-8844

J

278 BYTE May 1980

Circle 228 on inquiry card.

Circle 229 on inquiry card.

Take the mysteryout of programming

with the latest from BYTE Books'™

The BYTE Book of Pascal

Edited by Blaise W. Liffick

Based on the growing popularity of Pascal as aprogramming language, numerous articles,language forums and letters from past issues ofBYTE magazine have been compiled to provide thisgeneral introduction to Pascal. In addition, thisbook contains several important pieces of softwareincluding two versions of aPascal compiler - one writ-ten in BASIC and theother in 8080 assemblylanguage; a p-code inter-preter written in bothPascal and 8080 assemblylanguages; a chess playingprogram; and an APL in-terpreter written in Pascal.$25.00 Hardcover pp. 342ISBN 0-07-037823-1

The Vet

pa^a

.»

i

YOU JUST BOUGHTA PERSONALWHAT?

jure**"C,H!^ //y by Thomas Dwyer and Margot

,***&*" /:f Critchfield

Whether you are a novice pro-grammer or an experiencedcomputer user, this book is filled with practicalideas for using a personal computer at home orwork. It will take you through the steps necessaryto write your own computer programs, and thenshow you how to use structured design techniquesto tackle a variety of larger projects. The bookcontains over 60 ready-to-use programs written inMicrosoft and Level II BASIC in the areas ofeducational games, financial record keeping,business transactions, disk-based data file and wordprocessing. $11.95 pp. 256 ISBN 0-07-018492-5

Beginners Guide for theUCSD Pascal System

by Kenneth Bowles

Written by the originator of the UCSD PascalSystem, this highly informative book is designed asan orientation guide for learning to use the UCSDPascal System. For the novice, this book stepsthrough the System bringing the user to asophisticated level of expertise. Once familiar withthe System, you will find the guide an invaluablereference tool for creating advanced applications.This book features tutorial examples of programm-ing tasks in the form of self-study quiz programs.The UCSD Pascal Software Systems, availablefrom SofTech Microsystems Inc, 9494 Black Moun-tain Road, San Diego CA 92126, is a completegeneral purpose software package for users ofmicrocomputers and minicomputers. The packageoffers several interesting features including:

• Programs which may be runwithout alteration on theGeneral Automation or DECPDP-11 minicomputers, or anan 8080, 8085, Z80, 6502,6800, or 9900 basedmicrocomputers.

• Ease of use on a small, single-user computer with displayscreen and one or morefloppy disk drives.$11.95 ISBN 0-07-006745-7

Bed****

Hy+iCttt

These and other BYTE/McGraw-Hill books are availablefrom BYTE Books or your local computer store.

Please send

□

□

D

copies of The BYTE Book of Pascal. copies of You Just Bought a Personal What?copies of Beginner's Guide for the UCSD Pascal System

m

Add 75c per book to cover postage and handling.

Name

Title

Company

Street

City

State/Province

Code

□ Check enclosed in the amount of $ .

□ Bill Visa D Bill Master ChargeCard No

bllTE

fJflllnIS

Exp. Date._

BYTE BOOKS Division • 70 Main StreetPeterborough, NH 03458

B5

Circle 230 on inquiry card.

BYTE May 1980 279

The NCC:

New Emphasis on Personal Computing

What's happening in personal com-puting? The American Federation of In-formation Processing Societies, Inc(AFIPS) is banking that you'll find out atthe National Computer Conference'sPersonal Computing Festival, to be heldon May 20-22 in Anaheim, California atthe Anaheim Convention Center. In the3 years that personal computing has hada separate exhibit area at the NCC, thenumber of exhibitors has increased from76 to 154. Over 20% of those who cameto the NCC last year registeredspecifically for the Personal ComputingFestival, and over half of the 60,000 plusattendees visited the Festival.

The booming show-attendance figuresreflect the fast growth of the personal-computing industry as a whole.Highlights include the Apple ComputerCompany's expectations to triple its

sales by the end of 1980. Commodore In-ternational computer sales may increaseby a factor of 2 during the first guarter of1980, and Radio Shack expects similarincreases. According to industryestimates, the market value of personal-computer software sold in 1980 couldsurpass $150 million.

Judging from the attendance at lastMarch's West Coast Computer Faire inSan Francisco (approximately 20,000),there is an ever-increasing interest inpersonal computing among a widevariety of people. We expect to see atrend toward more sophisticated soft-ware at the 1980 NCC Personal Com-puting Festival. There will be a flood ofnew Pascal packages, new simulationprograms, the appearance of new Forthsoftware (look for the special sectionon the Forth language in the August

1980 BYTE), as well as intriguing newhardware like Microsoft's new Z80 pro-cessor circuit card for the Apple com-puter that allows Apple owners to useprograms written to run under DigitalResearch Corporation's CP/M operatingsystem. Word-processing and small-business software are two other rapidlygrowing areas that will be wellrepresented at the conference.

Will some major consumer electronicscompanies enter the personal computermarket? Is there a move toward somestandardization in the microcomputerindustry? Will lapanese companiesmake any major moves into personalcomputing? [Nippon Electric Company(NEC) is rumored to be unveiling a newcomputer at the show]. We'll keep oureyes open at the show to find outll

Personal Computing Festival

Preliminary List of Exhibitors

ABC Computer Inc

American Word Processing Co

Apple Computer Co

Applied Digital Data Systems Inc

Artec Electronics Inc

Atari

BASF Systems

Benwill Publishing Corp

BYTE Publications Inc

California Computer Systems

Cardamation Co

Centronics

Comprint

Compucolor Corp

Compucorp

Computer City

Computer Textile

Computer world

Computhink

Control Data Corp

Corvus Systems Inc

Creative Computing

Cromemco Inc

Diablo Systems IncDilithium Press

Electronic Data Systems-Evolution I

Executive Information Systems IncExidy Inc

Findex Inc

Harris TechnologyHayden Book Co IncH & E ComputronicsHeath/ZenithHewlett-Packard Co

Industrial Micro SystemsInternational Memories Inc (IMI)

Jade Computer Products

Leedex Corp

Lobo Drives International

LRC/An Eaton Co

3M-Data Recording Products Div

MAS (Micro Application Systems Inc)

Memory Media Products

MicroAge

Microamerica Distributing Co Inc

Microcomputer Technology Inc

Micromail

MicroPro International Corp

Microsette Co

Microsoft

NEC America Inc

North Star Computers Inc

Omni MagazineOsborne/McGraw-Hill

Personal Software

Priam

Prodigy Systems Inc

RCA Microcomputer ProductsRadio Shack

Realizations Etudes Electroniques (R2E)Rockwell Microelectronic Devices

SD Systems IncSharp Electronics CorpSmoke Signal BroadcastingSpectra Logic CorpSybex Inc

TEI IncTSA Software

Xymec

280 May 1980 © BYTE Publicalions Inc

Back, and Biggerthan Ever.

NCC

Personal Computing Festival

MaY20-22/DisneYlandHoiel

So great is the interest in personal com-puting, so dynamic is the personal computerindustry, that this year's Personal ComputingFestival is again being held separate from therest of NCC, at the Disneyland Hotel.

The 3-day festival features its own impres-sive roster of exhibitors plus over 50 learningsessions on every aspect of personal computersand their use.

Personal computers at home, at school,and in the executive suite. Personal computersas word processors, entertainment devices,and aids to the handicapped. Personal com-

puter operating systems, programming lan-guages, and software evaluation.

In addition, we've set aside a special areawhere demonstrations of personal computerswill be conducted throughout the show. Andwe're awarding prizes for the most interestinguse of personal computers.

If you're coming to NCC '80, be sure tomake The Personal Computing Festival part ofyour visit.

Who knows—you may even win a prize.

AFIPS, 1815 North Lynn Street, Arlington, VA 22209

Circle 231 on inquiry card.

BYTE May 1980 281

Personal Computing FestivalProgram Schedule

May 20 - Tuesday - 10:00 AM

Hiqh-Level LanguagesPascal Part IJim Gagne

Word ProcessingShopping by ObjectivesBill Radding

Portable Personal ComputingJim Flouinoy

1:00 PM

Higher-Level LanguagesPascal Part IIJim Gagne

Computer Hardware Considerations &

Applications

L Silvern

Forth Business ApplicationsJim Flournoy

2:30 PM

Networks You Can Access With YourPersonal ComputerCliff Barney

May 21 - Wednesday - 10:00 AM

Using Computers to Overcome Dis-ability HandicapsPartiJeff MoyerMaiy Anne Glicksman

The Future of Personal Computing

Panel

Verne Kallejian

Operating SystemsRoger Vass

1:00 PM

Using Computers to Overcome Dis-ability HandicapsPart II

Computer Networks-TechnicalCraig Vaughn

Software EvaluationTom Williams

2:30 PM

Computer MusicCarl Helmers

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May 22 - Thursday - 10:00 AM

Medical Computing forMicroprocessorsJim Gagne

Data Base ManagementDoug Seeley

Computers In EducationChris Morgan

1:00 PM

Use of Computers in Kindergardenthru Ninth GradeFlora Russ

Business ApplicationsNancy Leeper

Computers In Education PanelChris Morgan

2:30 PM

Programming Potpourri

1980 NCC

List ofExhibitors

Able Computer

Addison-Wesley Pub Co Inc

Advanced Systems Inc

AFIPS Press

Aham Inc/Rubber Urethane

Alanthus Data Communications Corp

Alpha Data Inc

Alpha Micro

AM International

Amco Engineering Co

American Magnetics Corp

American Terminal Leasing

Ampex Corp

Anadex Inc

Anderson Jacobson Inc

Ann Arbor Terminals Inc

Applied Digital Data Systems Inc

Applied Magnetics Corp

Aspen Ribbons

Association for Computing Machinery

Atlas Energy Systems

Audiotronics Video Display Div

Auerbach Publishers Inc

Aydin Controls

Ball CorpBASF SystemsBasic Four Corp

282 May 1980 © BYTE Publications Inc

Battelle Memorial Institute

BDT Buro-und Datenztchnik Gabil

Beehive International

Bell & Howell Display Devices

Bell System

Benson-Varian Int

Benwill Publishing Corp

Berger-Lahr Corp

Boschert Inc

British Trade Development Office

BTI Computer Systems

Burroughs Corp

CalComp

Caracters USA Inc

Centigram Corp

Centronics

Century Data Systems—A Xerox Co

Chromatics Inc

Cii Honeywell Bull

Cipher Data Products Inc

Circuit Assembly Corp

Clinton Electronics Corp

CMP Publications

Codex Corp

Compugraphic

Computer Automation

Computer Decisions

Div of Hayden Pub Co IncComputer DesignComputer DevicesComputer-Link CorpComputer Power SystemsComputer Products MagazineComputer Roomers IncComputer Science Press IncComputer Transceiver Systems IncComputerworld Computer Business

News (CW Communications)Computron Technologies CorpContal CorpConrac

Continental ResourcesControl Data CorpCortron & Licon Div IIWCullinane CorpCurtis 1000 IncCustom Systems IncCyberex Inc

Daily Business Products

Data Access Systems Inc

Data Communications/McGraw-Hill

PublicationsData Dimensions IncData Electronics IncData General CorpDatagraphic

Data-Mate/Maine Manufacturing CoDatamationDatamedia CorpData MotionData Printer CorpDatapro Research CorpData Processing Management AssocData Processing PowerDataran CorpData Specialities IncDataware IncDatum Inc

Deciteck

Delta Data Systems Corp

Deltec Corp

Diablo Systems Inc

Digi-Data Cor.

Digi-Log Systems

Digital Associates Corp

Digital Computer Controls

Digital Equipment Corp

Digitech Data Industries Inc

Digitronics Div Contec Information

SystemsDistributed Logic CorpDiva IncDocumation IncDOSC Inc (Digitron)Dranetz Engineering Labs Inc

Eastman Kodak Inc

Edge Technology Inc

Educational Data Systems

Eichner Systems Inc

Electronic Component News

Electronic News

Elgar Corp

Emergency Power Engineering Inc

Emerson Electric Co

Emulex Corp

Epic Data

Epicon Inc

Epson America Inc

Exide Power Conversion ESE Inc

Facit Inc

Fairchild Camera & Instrument

Floating Point Systems Inc

Florida Data Corp

Four-Phase Systems

Fujitsu Ltd

General Automation IncGeneral DataCom Industries IncGeneral Electric CoGeneral Robotics CorpGeneral Terminal CorpGMT Automatic IncGraphic ControlsGTE Sylvania

Hamilton Avnet

Harris

Haveg Industries Inc

Hazeltine Corp

HEI Inc

Hitachi America Ltd

Honeywell Information Systems Inc

Houston Instruments

Hutchinson Industrial Corp

IBM Corp

ICI American Inc

IEEE Computer Society (Computer

Magazine)Incoters Corp

Industrial Engraving Co IncInformation Processing IncInformer Inc

Infosystems Magazine/Hitchcock PubCoINMAC

Innovative Electronics Inc

Input

Integral Data Systems

Integrated Software Systems Corp

(ISSCO)Intelligent Systems CorpInterdyne Co

Interface Mechanisms Inc (Intermec)International Data CorpInternational Mathematical & Statistical

Libraries Inc (IMSL)International Power Machines CorpInterstate Electronics CorpIntertec Data Systems CorpC Itoh Electronics Inc

Japan Market Consultants DivEngineers International Inc

Kennedy CoKey Tronic CorpKnickerbocker CaseKybe Corp

Liebert CorpLogAbax SA—US Div

3M

Magnavox Display Systems

Mag-Tek Inc

Management Science America

Mathematics Products Group Inc

Maxell

McCormack & Dodge Corp

McGraw-Hill Book Co

MDB Systems Inc

Megatek Corp

Melco Sales Inc

Memorex Corp

MFE Corp

Micon Systems Inc

Micon Industries

Microcomputer Systems Corp

Microdata Corp

Micro Peripherals Inc

Micropolis Corp

Micro-Term Inc

Minicomputer Systems Inc

Mini-Micro Systems Cahmers Pub

Monolithic Systems Corp

Mostek Corp %

Motorola Inc

MBI Systems Corp

Nanodata Corp

National Computer Communications

CorpNational CSSNational Electric CableNational Technical Information ServiceNCR Corp

NEC Information Systems IncNetwork Systems CorpNewman Computer Exchange IncNicolet Zeta CorpNippon Peripherals LtdNixdorf Computer CorpNorthern Zelecon Systems CorpNortronics Co IncNova Electric Manufacturing Co

May 1980 © BYTE Publications Inc 283

Ohio Scientific IncOkidata CorpOntel Corp

Panasonic Co

Paradyne Corp

Peripheral Dynamics Inc

Perkin-Elmer

PerSci Inc

Pertec Computer Corp

Philips Test & Measuring Instruments Inc

Plessey Peripheral Systems

PolyMorphic Systems

Practical Automation

Precision Handling Devices

Prentice Corp

Prentice-Hall Inc

Prime Computer Inc

Princeton Electronic Products

Printronix Inc

Pro-Log Corp

Qantel CorpQantexQuantorQume

Rascal-Milgo IncRacal-VadicRadio ShackRamtel CorpRandomex Inc

Raymond Engineering IncRemex Div/Ex-Cell-OResource Management—Div of

Cutler WilliamsRanco Electronic Systems

SAS Institute Inc

Scientific Measurement Systems Inc

SCI Systems Inc

Sheldon Industries Inc

Shugart Associates

Society for Computer Simulation

Software AC

Sola—A Unit of General Signal

Spatial Data Systems Inc

Specialized Products Co

Sperry Univac

Storage Technology

Structured Methods Inc

Summagraphics Corp

Systems Furniture Co

TAS Products Co

Tally Corp

Tandberg Data Inc

Tandem Computers Inc

T-Bar Inc

TEAC Corporation of America

Technology Transfer Institute

Techtran Industries Inc

Tektronix Inc

Teledyne Instruments

APPLE® • CP/M • TRS-80™ •

USMAIL FOR CP/M

USMAIL is by far the best mailing list program available! Written completely In machinelanguage. Only requires 32K. Easy to use, interactive, command driven, comes with 2demos that automatically show how to use it Supports up to 1927 entries There arecommands to SORT. SEARCH, ADD. DELETE. CHANGE. COPY, MERGE, LIST, produceLABELS (many different ways), and more. Professionally designed and developed by anexpert in data base management systems. Special introductory price: $95 for diskette andmanual, $20 for manual only

APPLE®

*m

LINKER — A linkage editor/loader for APPLE DOS. Includesa library of subroutines (PRINT.( OPEN, READ, etc.) A must for all' assembler programmers.32K APPLE $49.95 DISKETTE

BENEATH APPLE MANOR — Ex-plore an underground labyrinth,fighting monsters and findingmagical treasures. Uses colorgraphics for floor plans.16K APPLE$15 CASSETTE $20 DISKETTE

BABBLE — Teach your APPLE toiflfcLr create its °wn stories, poetry,JT music, and color displays. In-r^'v, eludes editor, compiler, inter-\? ' preter and demo programs.16K APPLE$15 CASSETTE $20 DISKETTE

ASTROAPPLE — An astrologicalil*^Ab package that produces natal., ^^T" horoscopes. 30 day forecasts,(:'^.'i->\ and compatability ratings In-cludes an 18 page manual.32K APPLE$15 CASSETTE $20 DISKETTE

TRS-80"

SUPERMAZE — 10,000 cell maze generator, LEVEL II 16K $15 CASSETTE

TTT3D - 3-dimensional tic-tac-toe LEVEL II 16K $15 CASSETTE

Available by mail or at your local computer store California residents acid 6% sales tax CP/MAPPLE, and TRS-80 are registered trademarks of Digital Research. Apple Computer Co , andTandy Corp.

The

Software Factory

23849 LA SALLE CANYON DR.NEWHALL, CA 91321

Telefile Computer Products Inc

Telenet Communications Corp

Teletype Corp

Televideo Inc

Telex Computer Products

Terak Corp

Termiflex Corp

Tesdata Systems Corp

Texas Instruments

Timeplex Inc

Tokyo Juki Industrial Co Ltd

Topax Electronics

Toshiba International Corp

Trilog Inc

Triple I Inc

Tymnet Inc

Universal Data Systems

Van Nostrand ReinholdVan San CorpVector Graphic IncVerbatim CorpVersatec

Victor Data ProductsVistron CorpVu-Data Corp

Wabash Tape Corp

Wall Street Journal

Wang Labs Inc

Warrex Computer Corp

Wavetek Data Communications

Wescorp

Western Peripherals

Westrex OEM Products

John Wiley & Sons Inc

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Xerox Business Systems

Yourdon Inc

Zenith Radio CorpZilog Inc

NCC MainConferenceProceedings

During each of the 4 days of the NCC,there will be discussions and papersrelated to the following major topics.A detailed schedule of events will beavailable at the conference.

Computer Architecture

Covers design of equipment andsupporting technologies, and distribu-tion through networking. Includes deci-sions relating to supersystems, sur-vivability systems and data-base installa-tion.

284 May 1980 © BYTE Publications Inc

Circle 234 on inquiry card.

Applications of ComputerTechnologies

Explores the use of computers in enter-tainment, microcomputers and their im-pact, management of the computing tooland staff, and the role of inhouse andacademic education and training.

Data Base Management &Communications

State-of-the-art, user-oriented sessionson the storage, retrieval, and transfer ofdata. From hardware considerations tonatural-language access to a data base.

Office Automation

Every computer-related aspect of thisexplosive growth area, including elec-tronic mail. How computers are used,managed, and integrated in an overallautomated office.

Simulation Technologies

Where we've been, where we are, andwhere we're going with computer model-ing. Its value to small and largebusinesses and its role in decision sup-port will be discussed. Special sessionson solar energy-simulation modelingwill be included.

Software Engineering Technologies

Sessions on programming standards,software quality assurance, languages,and requirements engineering.Emphasis upon the needs and respon-sibilities of the user.

Social Dynamics and Special Topics

A broad spectrum of critical subjects:data security, legal issues, transborderdata flow, societal impact, voice com-munications, venture capital and itseffect upon technology.

Image Processing and Computersin Medicine

How image processing is used and willbe used in industry and medicine.Trends in facsimile data coding, com-pression, and standards. How doctorsuse image-analysis display.

Professional Development Seminars

Full and half-day seminars for the pro-fessional who wants to come away withsolutions and ideas he can implementnow. Half-day seminars tie in withregular program sessions.

Make America smarter.

Give to the college

of your choice.

Explains the theory and application of sta-tistical techniques which yielded a profitof 5-25% per dollar bet on a computerizedsample of 1,345 thoroughbred races."Elegant work... creative thinking...impressive"—Tom Ainslie, foremost handi-capping author and former Daily RacingForm columnist.

- CONTENTS -

If I'm So Smart, Why Ain't I Rich? • Horse Racing is a Stochastic

Process: "Darkness likely tonight, increasing chance of lightness

towards morning..!' • What We Need to Know to Bet: Don't

Expect the Expected • Multiple Regression: Declarations of

Dependence • The Database: Telling the Computer What

Happened • Data Weighting and Normalization: 1 Apple + 1 Orange

= 1 Fruit Salad • Generation of the Model Equations: GettingInvolved in Meaningful Relationships • The Kelly Criterion for Bet

Sizing: If You Lose You Can Always Go Out and Work to Get

Even • Simulated Wagering Tests: "Even if I made as little as a million

a day, then..!' • Getting Started: For Do-It-Yourself Types •

Regression Coefficients and Statistics • Annotated Bibliography

$14.95

VISA'

BITS

Boohs to arose tha impossible

25 Route 101 W, RO. Box 428. Peterborough, NH 03458 USAMon-Fri 9-5 TOLL FREE 800-258-5477 (in NH dial 924-3355).

inc.

SHIPPING CHARGESWe ship UPS insured unless Postal 4thclass is requested.

US: $1.75 1st book, $.75 each additionalbook, to a maximum charge of $4.00.Foreign: $1.50 per book to a maximumcharge of $5.00; Air Mail $7.00 per book.

Ask for book #999- B

BYTE

BACK ISSUES

TOD. SALE

The following issues are available:

1976: July; 1977: March, May thru December; 1978: February thru October,December; 1979: January thru December except March; 1980: January and MarchCover price for each issue thru August 1977 is $1.75 Domestic; $2.75 Canada and

Mexico; $3.75 Foreign. September 1977through October 1979 issues are $2.50Domestic; $3.25 Canada and Mexico;. ByTE/' $4.00 Foreign. November 1979 to

current is $3.00 Domestic; $3.75Canada and Mexico; $4.50Foreign.

Send requests with payment to:

BYTE Publications70 Main Street,Peterborough, NH 03458A ttn: Back Issues

May 1980 © BYTE Publications Inc 285

What's New?

MISCELLANEOUS

RS-232C-Compatible Paper-TapeReader

The Model 612 stand-alone paper-tapereader has the ability to read five- to eight-level tape and to transmit seven to elevenframes per character at 50 to 9600 bits persecond (bps). It also features starting andstopping on character at all speeds, manualcontrol or automatic on and off, 90to 260 VAC, 50 to 60 Hz, and even,odd, or no parity. RS-232C, currentloop, or parallel outputs areavailable. The price of the 612 is $656 to $854. Contact Add-master Corp, 416 Junipero Serra Dr, San Gabriel CA 91776.

Circle 562 on inquiry card.

Bidirectional Interface forthe PET

This interface package is a combina-tion of hardware and software thatenables any model of the CommodorePET to send and receive data onprinters, terminals, and otherperipherals. ASCII/ISO-7 characters aresent from the PET in serial or parallelmode but are received in serial modeonly. Serial speeds are selectable at ratesup to 240 characters per second (cps).The interface is available for either 20mA current loop or transistor-transistorlogic (TTL) serial or parallel. Themachine-language program may bestored anywhere in programmablememory; the code used to terminate amessage is selectable. The price for thepackage is £70 (approximately $160).Further details from Allen Computers,16 Hainton Ave, Grimsby, SouthHumberside, ENGLAND.

Circle 563 on inquiry card.

Centronics-CompatibleSwitching and MonitoringUnits

Large Capacity WinchesterBackup from Corvus

This backup system, the Mirror,employs a standard video cassette with atotal capacity of 100 megabytes. In lessthan ten minutes, the 10 megabytes ofdata on the Corvus 8-inch hard disk canbe transferred to a Mirror cassette. Thevideo cassette should be of the VHS,Beta, or U-Matic format. If a larger datacapacity is required, a reel-to-reel video-tape recorder can be used. This ap-proach to storage embodies standardtelevision technology and provencassette reliability. The Mirror uses thesame Z80 and Corvus interface bus asthe Corvus disk. The Mirror will inter-face to the Apple II, TRS-80, S-100, andLSI-11 computers. Data format in theMirror is fully compatible with the stan-dard NTSC signal. For error detection,the Mirror contains cyclic redundancycheck (CRC) detection hardware. Ifunattended or remote operation isdesired, a low-cost option is available tointerface the Mirror to the PanasonicOmnivision NV-8200 cassette recorderallowing archival storage files to becreated without operator interaction.The price of the Mirror is $790. WriteCorvus Systems, 900 S Winchester Blvd,San Jose CA 95128.

Circle 565 on inquiry card.

Giltonix Inc, 450 San Antonio Ave,Suite 44, Palo Alto CA 94306, has in-troduced a family of switching andmonitoring units. The GRS 232 units areused for interfacing, configuring, andmonitoring computer terminals,printers, and other peripherals that com-ply with the RS-232 and the IEEE-488specifications. The new family consistsof four models: the GRS 232-P24, -S24,

-2P24, and -2S24. Each unit consists of ,standard three-way switching systemand an optional interface monitor. Allthe units can be cascaded and therebyallow interfacing of more than fivedevices. The systems can be orderedwith signal monitoring capability. Theunits are priced at approximately $130.

Circle 564 on inquiry card.

286 May 1980 © BYTE Publications Inc

What's New?

MISCELLANEOUS

Speechlink VoiceRecognition for S-100Computers

Heuristics has announced its Model20S-64 Speechlink 64-word voice inputunit for S-100 bus computers. The20S-64 is a speaker-programmed,isolated word-recognition device thatrecognizes up to 64 words at each in-stant. Vocabulary sets may be storedaway and recalled when needed. Thissystem will produce a usable vocabularyof several hundred words for data entryand system control applications. Wordrecognition is completed in 200 ms. Suc-cessive words must be separated by atleast 100 ms of silence. Preprogrammingof the Speechlink is necessary. The unitrequires 2 K bytes of programmablememory for programs, and 64 bytes foreach word in the vocabulary, up to amaximum of 4 K bytes. The price is$299 including board, microphone, andmanual. Contact Heuristics Inc, 1285Hammerwood Ave, Sunnyvale CA94086.

Circle 441 on inquiry card.

Hardware and Softwarefor Homebrewers

Snow Micro Systems Inc, POB 1704,Silver Spring MD 20902, provides low-cost hardware and software to personalcomputer users and clubs. Their bareboards are sold with schematics, layoutdrawings, and component lists. They are

Graphics TerminalEmulator for Apple lis

TEKSIM, the Tektronix Simulator,employs distributed processing in itsprogramming approach and uses theApple's high-resolution plottingcapabilities to emulate Tektronix4010-series graphics terminals. Nomodification to the program in theremote computer is required to display

or input graphic data. The TEKSIM-Apple combination features multi-colored displays, selective erase, and astandard video output that lets anytelevision set used with an RF converterfunction as a monitor. The suggestedprice for the plug-in device is $795, andit is available from ABW Corp, POB M1047, Ann Arbor MI 48106.

Circle 442 on inquiry card.

unassembled and come without parts.The company offers a troubleshootingservice, if necessary. Some of their pro-ducts include a front panel interfacecard, the Golem-80 S-100Troubleshooter, a Station ControllerCard, and more. Snow Micro software

includes AMS-80 Version 5.8 debugpackages, object code and source code,and other AMS-80 software relateditems. For prices and information, con-tact Snow Micro Systems at the aboveaddress.

Circle 443 on inquiry card.

CP/M Package for theSTD Bus

Micro/sys has developed a CP/Msystem for the STD Bus microcomputercard system. The Micro/sys packageconsists of two STD Bus-compatiblecards, the SB8500 Floppy Disk Con-troller, the SB8420 Dual Serial Interface,and an eight-inch floppy disk containingthe CP/M system. The SB8500 can con-trol up to four floppy disk drives from asingle STD Bus slot. The SB8420 pro-vides communication with a consoledevice, and a second serial port that canbe used for printers and other devices.The cards are compatible with 8085 andZ80 microprocessors.

CP/M provides a disk file manage-ment, a text editor, and an 8080assembler, a dynamic debugger, andvarious utilities. Price of the Micro/sysCP/M package is $695. For more infor-mation, contact Micro/sys Inc, 1353Foothill Blvd. La Canada CA 91011.Circle 444 on inquiry card.

May 1980 © BYTE Publications Inc 287

Whsft New?

MISCELLANEOUS

Video Graphics for S-100 Bus Systems

A single-card, high-density, computer-display system is being offered for the S-100 busby International Product Development Incorporated (IPDI). The VG100 is designed fortext-oriented applications. It has programmable fonts allowing any set of up to 256characters to be defined in programmable memory with available software. The systemcan generate a combination of 16 gray levels or 16 colors, or combinations of both. The

character field is 9 by 16 (or144) pixels with a raster scanof 621 pixels. The entirecharacter field can bechanged at one time for fastanimation. Adjoiningcharacter fields of any shapecan be combined to createlarge continuous characters.The VG100 is configured in12 K bytes of programmablememory and is selectable inthree 4 K-byte blocks. Theprice is $645. For details,contact IPDI, 1708 StierlinRd, Mountain View CA94043.

Circle 589 on inquiry card.

Video Terminal Board

T|>H>iitmrt»r miiHrtttmmi

This board features full uppercase and lowercase, 5 by 7 dot matrix, 16 lines with 64columns, and serial RS-232 input and output with parallel keyboard input. The datarate generator has a range from 75 to 1200 bits per second (bps) and is jumper-selectable. The board has 1 K byte of memory and an SFF96364 processor integratedcircuit. The device is S-100 compatible. It requires ± 16 VDC at 100 mA and 8 VDC at1A. The price is $199.95 in kit form. Contact Electronic Systems, POB 21638, San JoseCA 95151. Circle 590 on inquiry card.

64 K Byte Memory for Heathkit/Digital Hll

The CI-1103 memory module is designed for the Heathkit/Digital Hll, LSI 11/2,and PDP 11/03 computers. The product uses 200 ns cycle time, type-4027, 4 K by1-bit dynamic memory parts or 200 ns, type-4116, 16 K dynamic memory devices.The CI-1103 is available with either on-board distributed refresh or external refreshcontrol logic. Data access time is 300 ns and cycle time is 525 ns. On-board memory-select is available in 2 K in-crements up to 128 K wordsof memory. Power con-sumption is under sevenwatts. The 8 K by 16 boardis $390 and the 32 K by 16board is $750. For informa-tion, contact Chrislin In-dustries Inc, 31352 Via Col-inas #102, Westlake VillageCA 91361.

Circle 591 on inquiry card.

Serial Interface Card forApple II Computers

California Computer Systems' 7710AAsynchronous Serial Interface cardenables the Apple II to communicatewith all RS-232C serial devices. It isfully compatible with Apple Pascal. Thecard features selectable data rates from50 to 19,200 bits per second (bps), 8- or9-bit character transmission, and op-tional odd, even, or no parity. Softwareprogrammable interrupts, double buf-fered data input/output (I/O), and fullhandshaking are included. It is availablein kit form or fully assembled andtested. The price for the card is $159.95.For more information, contact Cali-fornia Computer Systems, 250 Carib-bean, Sunnyvale CA 94086.

Circle 592 on inquiry card.

Percom Board InterfacesSpeak & Spell toComputer

Percom Data Co, 211 N Kirby,Garland TX 75042, has announced pro-duction of a printed circuit board whichwill interface the Texas InstrumentsSpeak & Spell learning aid to a com-puter. The "Speak 2 Me 2" allows com-munication with a Speak & Spell inBASIC, so a computer can talk using thewords and phrases of a Speak & Spellunit. The board is installed in the bat-tery compartment. Installation involvesdisassembly and some modification ofthe Speak & Spell unit. The board withinstructions, TRS-80 driver software,and a TRS-80 cable sells for $69.95. Thecable connects to the printer port andmay be adapted for other computers.Circle 593 on inquiry card.

Head-Cleaning FloppyDisks from Lifeboat

Lifeboat Associates, 2248 Broadway,New York NY 10024, has an importantproduct for floppy-disk systems: headcleaning disks. The head-cleaning floppydisks are manufactured by attaching alint-free nylon mat to a mylar substrate.The design avoids damaging abrasion,which keeps head wear to within in-dustry standards for normal magneticmedia. The disk is used by inserting itinto the drive in the same manner as afloppy disk, and loading the head for 30seconds. It is recommended that thisprocedure be used once per day asprevention against oxide build-up. Thedisks are available in 5Vi- and 8-inchsizes for $20 each, or $45 for three. Eachdisk is suitable for three months of dailyuse. Circle 594 on inquiry card.

288 May 1980 © BYTE Publications Inc

GVHDE.TO PERSONAL

COMPUTING

GETTVMG ST/^TED

Wttat You Need Ancmvhat It Will Cost

EQVJ\Plv\ENT REVIEWS

TRS-80, Apple, Sorcerer and PETBest-Selling Author

1ERRV POURNELLl

••vt-rfUns WHh A Microcomputer'

THE BtN/^RY WORfl

A PERSONAL

COMPUTER DIRECTORSCOMPUTER CLUBS:WHO WEEDS THEM?

When willExplosi

Are you prepared for the explosivetransformation? Right in your ownhome? Electronic mail. Personalized *investment analysis. Foreign languagetutorial. Home energy management.Robots. Computer music. Secretarialservice. Diet and menu planning. And

more, more, more.

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onCompating™ the new McGraw-Hillquarterly, prepares you for theenormous changes coming during the

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onCompating™ explains in nontechnical

language what personal computers are,

how they work, and how you can use

them at home, for fun and profit.

Don't let the personal computer

explosion catch you off guard. Know

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DOMESTIC subscription rate: is 1□ U.S. 1 yr. (4 issues) @ $8.50 □ Canada & Mexico, 1 yr. (4 issues) @ $ 10.00 £ |

FOREIGN (to expedite service, please remit in U.S. funds drawn on a U.S. bank.) B 1D Europe (and all other countries, except above), 1 yr. @ S 12.00 — surface delivery. 5" |

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D Bill Visa □ Bill Master Charge □ Bill me (North America only) £ '

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© onComputing. Inc. 1980

Card Number Expiration 8 |

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City State/Province/Country Code 7R.cn '

What's New?

PUBLICATIONS

Hardside AnnouncesExpanded New Catalog

Hardside, a mail-order hardware com-pany in Milford, New Hampshire, hasannounced the release of an expandedversion of the Hardside catalog. Hard-side features Radio Shack computer pro-ducts at a discount price and alsoperipherals from other manufacturerswhich are suited to work with theTRS-80. The company specializes incomputers and related hardware. TheHardside catalog is free from Hardside,6 South St, Milford NH 03055.Circle 572 on inquiry card.

Monthly NewsletterCovers the OfficeComputing Industry

Entitled the Office Computing In-dustry Report (OCIR), this monthlynewsletter focuses on small-scale dataprocessing, word processing, and datacommunications systems. OCIR alsocovers the merging of EDP and BusinessMachine distribution systems and sup-port activities and the relationship ofthese new office computing systems tonetwork-based information systems anddistributed data processing. Newsanalysis, market forecasts, new productreviews, vendor profiles, and technologyforecasts are included. The Office Com-puting Industry Report is available fromVantage Research Inc, 2680 E BayshoreRd, Mountain View CA 94043, for $195per year in North America and $225 inEurope and Asia.

Circle 566 on inquiry card.

Supplies Catalog fromDiablo

A 25-page brochure from DiabloSystems Inc, 24500 Industrial Blvd,Hayward CA 94545, illustrates anddescribes the variety of print wheels andribbon cartridges designed for use on thecompany's Series 1640 and 1650,HyType, HyTerm, and matrix printersand terminals. The brochure contains asample type line from all of the plasticand metallized daisy-wheel printelements. For copies of the brochure andthe name of the nearest Diablo dealer,call (800) 227-2076, except in Californiawhere the number is (415) 443-2273.

Circle 567 on inquiry card.

S-100 Magazine BeingPublished

MIQRO SYSTEMS

JAN/FEB1980 VOL.1/NQ1

THE

IEEE S-100

STANDARD

HASARRIVED!

MMffvInQ rno ;i>5 VM-10I4 n oibwCompuluttad fcilMim loom Iptomt n KMI >-

Ml 6M0 DTiou.mbl.l irWMMffMW

S-100 Microsystems is a new publica-tion directed towards users of S-100microcomputer systems. It is a forum onsuch S-100 topics as interfacing, CP/M,Pascal, Assembler, FORTRAN, andBASIC software. The magazine will alsocover 16-bit microprocessors,multiprocessors, multitasking, time-sharing, word processing, systemdevelopment, data base management,scientific, and other applications andissues. It will be concerned with S-100systems such as Cromemco, North Star,Intersystems, IMSAI, Poly Morphics,Processor Technology (Sol), Xitan, andothers.

S-100 Microsystems is edited by SolLibes. Sol has written 13 books, manymagazine articles, and has edited severalnewsletters. He is the founder and pastpresident of the Amateur ComputerGroup of New Jersey, the largest per-sonal computer organization in theworld. The first issue of S-100Microsystems includes the complete pro-posed Institute of Electrical and Elec-tronics Engineers (IEEE) S-100 Standard,the first part of a tutorial on CP/M, anarticle on modifying the SDS VideoBoard for Pascal editor functions, thesource code for an 8080 disassembler, adirectory of Computerized BulletinBoard Systems (CBBS), and more. S-100Microsystems will be published six timesa year. A sample copy is $2. Forsubscriptions and additional informa-tion, contact S-100 Microsystems, POB1192, Mountainside NJ 07092.

Circle 568 on inquiry card.

Short Form Catalog andPrice List

Sara-Tech Electronics Inc, POB 692,Venice FL 33595, has published a catalogwhich includes systems and peripheralsfrom Cromemco, North Star, Cen-tronics, Heath, and many more com-panies. They also have a listing forcomputer-paper forms for all systems.Sara-Tech sells systems, peripherals, andsoftware of most major companies.Circle 569 on inquiry card.

A Book on ComputerizedTypesetting

Donald Knuth, author of The Art ofComputer Programming, has writtenTEX and METAFONT, New Directionsin Typesetting, which describes newtechniques in typesetting. Dr Knuth ex-plains how TEX, originally designed foruse in setting technical and mathematicaltext, can be applied to all computerizedtypesetting. METAFONT is a system forthe design of alphabets. It is suited forimplementation on raster-based devicesthat print or display text. With it, com-puters can draw new fonts of charactersin seconds. TEX and METAFONT repre-sent improvements in typesetting thatwill benefit the scientific and technicalcommunity. The book consists of threeparts. The first is a lecture onmathematical typography; the two otherparts describe TEX and METAFONT.The book costs $12 and is availablefrom Dept TM:X, Digital Press, Educa-tional Services, Digital Equipment Corp,12-A Esquire Rd, N Billerica MA 01862.

Circle 570 on inquiry card.

Software Catalog forHeath Users

The Heath Users' Group has publisheda catalog of programs written by Heathusers for all Heath computers. The pro-grams described include games, financialapplications, utilities, computer-assistededucation, and amateur radio. Thecatalog lists the language and designatedcomputer next to the program. Pricesare given, along with services of theUsers' Group. For more information,contact Heath Users' Group, Hilltop Rd,St Joseph MI 49085.

Circle 571 on inquiry card.

290 May 1980 © BYTE Publications Inc

Whsft New?

SYSTEMS

Intellivision from Mattel

Mattel Electronics is introducing sixcartridges for its home computer system,Intellivision Intelligent Television.Soccer, Golf, Skiing, Boxing, Tennis,and Sea Battle join the existing fourteencartridges, which range from sports andgames to children's learning. Intellivi-sion's Master Component contains a16-bit microprocessor that deliverssimulated sound effects, three-part har-mony, and color reproduction. Two12-button, hand-held controllers, eachwith four play-action keys, and a16-directional control knob for move-ment of screen objects are included. Theunit attaches to any television set.

The Keyboard Component uses pro-grammed cassettes and features akeyboard and a digital cassette systemwith fast-forward and tape search.Its programs include Physical Fitness,Speed Reading, Stock Analysis,

and Guitar Lessons. The Master Component will retail for approximately $300 or less. The Keyboard Component will cost around$550 and the cartridges will cost approximately S30, with the cassettes priced slightly under $30. For information, contact Mattel Elec-tronics, 5150 Rosecrans Ave, Hawthorne CA 90250. Circle 586 on inquiry card.

Computer System from NNC

NNC Electronics, 15631 Computer Ln, Huntington Beach CA 92649, has released the System 80 computer. The System 80 uses a 4MHz Z80 microprocessor and features a floppy-disk controller and two dual-density, 8-inch disk drives, 32 K bytes of programmablememory, two serial ports, and the CP/M operating system. The eight-slot S-100 card cage has five slots available for expansion. Thedesktop unit weighs less than 29 kg (65 pounds) and retails for $3995. Circle 587 on inquiry card.

Altos Announces a Hard-Disk System

The Altos Systems ACS8000-6 can take advantage of as much as 58 megabytes of hard disk storage. The system can control up tofour 14.5-megabyte Shugart disks using Winchester-type technology. Altos designed the ACS8000-6 series so that it handles up to four

floppy-disk drives. The floppy unitscould accommodate another 4.0megabytes of on-line storage. TheACS8000-6 family comes with in-put/output (I/O) control to support twoserial and two parallel ports in additionto the four serial ports to which theusers are connected. The hard-disk con-—. troller features direct memory access

| JJ <■ m M (DMA) operation; firmware address

checking; a high-speed first-in, first-out(FIFO) buffer; and intelligent sequenc-ing. The controller firmware contains aroutine that automatically double-checksall addresses before performing any diskwrites. The FIFO enables the system totransfer data at a 7 million bits per se-cond (bps). The system will supportasynchronous, bisynchronous, and net-working communications protocols andconfigurations. Prices range from $9450for a single-user system with twofloppy-disk drives and one14.5-megabyte hard disk, to $14,260 forthe four-user, 29-megabyte system withtwo dual-sided floppy-disk units. Fordetails, contact Altos, 2338A WalshAve, Santa Clara CA 95050.

Circle 588 on inquiry card.

May 1980 © BYTE Publications Inc 291

What's New?

SOFTWARE

A North Star Program for Salesmen

The Sales Master One is a collection of 22 programs designed by salespeople for salespeople. The Sales Master One is territory-oriented, allowing users to pinpoint selling activities to a particular location. The system generates reports on sales activities,

forecasts, and schedules. Various otherreports assist in daily selling efforts. Thesystem has room for 400 jobs on one5Vi-inch floppy disk. The package con-tains a program that allows modifica-tions to be made without the need torefer to the operations manual. Acustomized disk-operating system allowsthe package to be run on Cromemco,Dynabyte, and Processor Technologycomputers. Sales Master One comes ona SVo-inch floppy disk with a manualfor $375. Contact Gemini InstrumentsInc, POB 205, Larchmont NY 10538.

Software fromCompucolor

Compucolor Corp, POB 569,Norcross GA 30091, has released severalsoftware programs for the CompucolorII system.

The BASIC Editing package featuressix programs including FRED (FriendlyEditor), RENUM (Renumber), MERGE,COMPAC, REMPAC (DeletesRemarks), and BASSRC (BASIC-to-Source Conversion). FRED, the most

useful of the programs, allows the userto edit any line, move existing lines,delete a range of lines, and to search forthe occurrence of any string, variable,or command within a program. Thepackage comes on a floppy disk andcosts $29.95.

Statistics is a series of three disks thatis useful for engineering applications.The floppy disks are entitled Statistics I,II, and ///. Each disk contains five pro-grams including plot, stat, polreg(polynomial regression), index, and

Circle 573 on inquiry card.

more. Common to all three packages isa file manager program that generates,maintains, and displays files for use byother programs. Statistics I sells for$24.95. Statistics II and /// sell for$29.95 each.

Compucolor has also released Sound-ware. This program includes the soft-ware and hardware necessary to createsounds on the Compucolor II. It is writ-ten in BASIC, with a range of two tothree octaves. The price is $49.95.Circle 574 on inquiry card.

TLC-LISP for Z80 Systems

The LISP Company has announced itsversion of the LISP language for theZ80. TLC-LISP allows manipulation offunctions as data objects; promotesobject-oriented programming style;defines functions with a variable numberof parameters; includes structured itera-tion and nonstructured escapemechanisms; contains complete stringand character processing capabilities;and includes fixed- and floating-pointarithmetic. The language system alsocontains a table-driven scanner; com-

prehensive error control, an autoloadfeature that "virtualizes" infrequentlyused functions and constants to diskfiles, freeing programmable memory;and execution speeds comparable to aKA-10 running MACLISP. Over 150utility functions are provided. TLC-LISPis available for Z80 CP/M systems andother versions will be available soon. Adetailed manual is $15, and the systemon 5- or 8-inch floppy disks is $150.Write The LISP Co, POB 487, RedwoodEstates CA 95044.

Circle 575 on inquiry card.

Software Catalog forTRS-80 Level II

National Software Marketing Inc,POB 6195, Hollywood FL 33021, hasannounced a free catalog of software forthe TRS-80 Model II. The softwaredescribed includes accounts receivableand payable, general ledger, payroll,inventory, rental mangagement, and avariety of financial and mathematicalprograms. These systems will operate onthe 64 K-byte model with the built-indisk. The programs have list prices of$15 to $100. Circle 576 on inquiry card.

A Gomoku Program

Five Stones Software, POB 1369,Station B, Ottawa, Ontario, KIP 5R4,CANADA, has released a Gomoku pro-gram for North Star Horizon disk-operating systems and CP/M-basedsystems. The program features a bookof openings with 200 entries, the abilityto take back moves, a 19 by 19 board,recent moves displayed along with theboard, and the ability to customize todifferent screen sizes. The program re-quires a minimum of 32 K bytes of pro-grammable memory and is available on5-inch floppy disks for $29.95.Circle 577 on inquiry card.

PLMX — A Language ThatCommunicates with All 8-or 16-bit Microprocessors

PLMX is a universal high-levellanguage for microprocessors. It can beused with all 8- or 16-bitmicroprocessors and was designedprimarily for use in microcomputer pro-duct development systems and in real-time process-control applications. PLMXsyntax is identical to PL/M, so theentire library of existing PL/M programscan be compiled under PLMX. PL/Mprograms may be used on micro-processors other than the 8080 through

the PLMX compiler. PLMX is a truecompiler, allowing fast compiling times—useful for real-time applications. It hasbeen developed as a user-orientedlanguage. There are no arbitrary format-ting rules or line numbers. Commentsmay occur anywhere in the source text,except within reserved words, identifiernames, and numbers. PLMX is priced at$1000, which includes an 8-inch com-piler floppy disk and instructionmanuals. To obtain additional informa-tion, write Systems Consultants Inc,Product Development Group, 4015 Han-cock St, San Diego CA 92110.

Circle 578 on inquiry card.

292 May 1980 © BYTE Publications Inc

What's New?

SOFTWARE

High-Speed Sort Utility forOhio Scientific

BPSort is a high-speed, assemblylanguage, sort/merge utility program forOhio Scientific floppy and hard disksystems. It is capable of sorting 20 Kbytes in ten seconds. Files can be anentire hard or floppy disk in length.BPSort handles fixed length records.Five keys can be specified for ascendingand/or descending sequence. Sortparameters are established using aBASIC program. BPSort is OS-DMScompatible and is supplied as part of theBPS, an interactive data managementsystem. It is sold in single-user licensedcopies for $124. Earlier versions can beupdated for $25. Order from BPS, 322W 57th St, New York NY 10019.

Circle 579 on inquiry card.

Microsoft to MarketmuLISP and muMATH

Microsoft has become the distributorfor muLISP-79 and muMATH-79, which'were written by the Soft Warehouse ofHonolulu, Hawaii. muLISP offers all ofLISP's programming features, including83 LISP functions, flexible program-control structures, and infinite precisioninteger arithmetic in any desired radix (2to 36). The modular muMATH symbolicmathematics package is useful for scien^tific and engineering applications. ThemuMATH routines are written inmuSIMP, which is included in the

package. Both programs run with CP/Msystems. The muLISP program costs$200 and the muMATH/muSIMP-79program is priced at $250. ContactMicrosoft, 10800 NE Eighth, Suite 819,Bellevue WA 98004.

Circle 581 on inquiry card.

Microsoft AnnouncesTRS-80 Model II Software

Microsoft is selling TRSDOS-compatible versions of its COBOL andBASIC compilers for the TRS-80 ModelII. Both compilers provide completefacilities for commercial or in-housesoftware development, including

Microsoft's macroassembler and linkingloader. The COBOL-80 compiler is an JANSI-74 implementation of COBOL.The BASIC compiler produces objectcode that runs faster than interpretedBASIC programs. All Microsoft BASIClanguage features are supported. TheBASIC compiler is also available in aversion for the TRS-80 Model I.Microsoft is the author of Radio Shack'sBASICs. The BASIC compiler is$395,and the COBOL-80 compiler is I$750. Contact Microsoft, 10800 NEEighth, Suite 819, Bellevue WA 98004.Circle 580 on inquiry card.

Six Programs for TRS-80Level II and Disk-Operating System

International Data Services hasdeveloped Microsketch III, a graphicsprogram for the Level II with 16 K bytesof programmable memory for $7.95.Freakout is a keyboard-generatedgraphics and sound program for theLevel II with 4 K bytes of programmablememory for $3.95. The number-baseconversion program converts any baseto any other base between 2 and 16. It ispriced at $3.95. Three other programsare available for disk BASIC with 16 Kbytes of programmable memory. BASICto Electric Pencil file conversion,machine language to BASIC data state-ment conversion, and mail-list file up-percase to uppercase-and-lowercase con-version programs all cost $3.95. ContactIDS, 340 W 55th St, New York NY10019. Circle 582 on inquiry card.

RCA's BASIC I Compiler/Interpreter for COSMACDevelopment System

RCA's BASIC I Compiler/InterpreterCDP18S834 is a software package thatcan accelerate program development onthe COSMAC DOS DevelopmentSystem CDP18S007. The package givesthe user the option of developing andrunning programs in BASIC I or con-verting the programs to object code. Theoutput of the compiler is assembled bythe COSMAC macroassembler to pro-duce the executable object code. Someof the features of the compiler/inter-preter include: 70 characters per line,variable designation by a single capitalletter, and fixed-point arithmetic. BASICI functions include MOD, AND, OR,XOR, and USR. The USR function ex-tends BASIC 1 by means of machine-language subroutines. Some of thestatements available to the programmerare REM, LET, GOTO, IF, INPUT,WFLN, and NEW. With a manual, thepackage is priced at $300. Contact RCASolid State Div, POB 3200, SomervilleNJ 08876.

Circle 583 on inquiry card.

A Data Base System forthe TRS-80

V R Data Corp, 777 Henderson Blyd,Folcroft PA 19032, has announced aData Base system for the TRS-80 ModelsI and II. The Data Base system providesthe capability to define and create cus-tomized records for various applications.Records may contain up to 25 user-defined variable-length fields and up to250 characters per record. A dictionaryof the fields and their characteristics ismaintained by the system. Records maybe added, deleted, and extended; fieldcontents may be changed, and fieldsmay be removed or added to the recordor renamed at any time. Records mayalso be linked logically. The recordsmay be sorted by any combination offields in ascending or descending order.Reports are fully user-definable and maybe routed to a printer or the videodisplay. This four-program BASICsystem requires 48 K bytes of program-mable memory, a minimum of two diskdrives and a line printer for the TRS-80Model I, with 300 records per disk. Pro-grams are available for the Model IIwith 950 records per disk.

Circle 584 on inquiry card.

Machine-LanguageProgram for TRS-80 DiskSystems

The ST80-111 machine-language pro-gram is written for the TRS-80 Level IIsystem. This package includes programsthat allow users to talk to a time-sharingcomputer, transfer files to and from thecentral computer, and customize theST80-111 system. Some of the programsincluded in the system are a BASIC pro-gram that creates translation tables, onethat tells if a file is American StandardCode for Information Interchange(ASCII) or binary, a binary-to-ASCIIconversion program, and one thatchanges machine-language programs tobinary. The ST80-111 has been run onHP2000, IBM 370 and 360, PDP-11,Burroughs, Apple, and North Starsystems. The minimum requirements forthe system are the TRS-80 Level II withone disk drive and 16 K bytes ofmemory, an RS-232C board, and amodem. The package is produced bySmall Business Systems Group, Main Stand Lowell Rd, Dunstable MA 01827,and is priced at $150.

Circle 585 on inquiry card.

May 1980 © BYTE Publications Inc 293

GET Paid

for using yourComputer *j

FUN' EasN £53 V

RUSH COUPON FOR ^5>^ FREE FACTS

VG^ SPARETIME [5F~f5?i

Send today to — DAR- B5 yi »3110 Fulton Ave, Sacramento CA 95821

TRS-80 Model I and II quality software

DAIA BASE MANAGER KIM IV $69

You can use it to maintain a data base & produce reports without anyprogramming Define die parameters & report formats on-line Features keyrandom access last multi-key sort field anth label generator, audit logMOD-II version with more than SO enhancements S199

ACCOUNTS RECEIVABLE ACCMII $69

One or more drives Older entry calculates sales lax shipping, amount loimultiple items Credit checking aging sales analysis invoices statementsand reports As opposed to most otner A/R ours can be used by doctors storemanagers etc MOD II version S149

WORD PROCESSOR 16K S39 32K $49 MOD-II $49

Fusl word processor specifically designed for the TRS-80 that uses diskstorage for text Written in BASIC No special hardware and text limit Use forletters manuals & reports 32K version features upper/lower case withouthatdware change and multiple input text files

HAILING LIST advanced MAIL-V $59

Fast sort by any field Multiple labels and reports 4-digit selection code, newup code ext screen input live keyboard powerful report writer M0Q-IIS99

INVENTORY INV-V $99

9 digit alphanumeric key for fast key random access Reports include orderinfo, performancesummaiy etc Calculate EOQ Powerful report writer MOD-II $149

All programs are on-line interactive random access virtually bug Ireedocumented and delivered on disks MDD-I requires 32K DOS We challenge allsoftware vendors to offer low cost manuals so you can compare and avoidIhose high-priced undocumented on-memory' programs Send S5 for a MOD-Imanual and S10 for MOD-II

MOD-II programs are extensively modified guaranteed to run with t yearnewsletter I updates lift off for ordering more than I MOD-II programs

MICRO ARCHITECT

96Dothan St., Arlington. MA 02174

c-io SHORT so ft.

CASSETTES

^&L

Qhj.

Price

1

$1.00

10

$0.75

SO

S0.65

Circle 236 on inquiry card.

Circle 237 on inquiry card.

Premium tape and cassettes acclaimedby thousands of repeat order microcom-puter users. Price includes labels, cas-sette box and shipping in U.S.A. VISAand M/C orders accepted. Californiaresidents add sales tax. Phone (415)968-1604.

MICROSETTE CO.

475 Ellis StreetMt. View, CA 94043

Circle 238 on inquiry card.

TRS-80 II

TWO NEWCASSETTES

• VENTURE ANALYSIS •

ANALYSE VARIOUS EFFECTS

IN MINUTES

7 YR RESULTS INCLUDE:

REVENUES, COSTS

BT & AT EARNINGS

UNDEPRECIATED CAPITAL

CASH FLOW - ROIC

AND OTHERS

16 K 14.95

• DUPL. BRIDGE SCORING •

4, 5, 6 TABLES

HOWELL MOVEMENT -

ENTER SCORES, BOARD

AND PLAYER TOTALS

16K 6.95

Check or M.O. To:

RLK SOFTWARE

1310 E. Clarendon St.Arlington Heights, IL 60004

(Oduct versatility and value

IN NEW YORK CITY \

i

OHIO SCIENTIFIC &ARISTO/

POLKS FULL STOCK AND SER-VICE ON CHALLENGER MICRO-COMPUTERS.

CHALLENGER C1PBK S399.00

C1P 5" FLOPPY 20K $1198.00

SUPERB0ARDC1P $279.00

CHALLENGER (COLOR) C4P BK $698 00C4P FLOPPY 24K 5" $1698 00

CHALLENGER C8P $895.00

COLOR-DUAL 8" FLOPPY C8P $2597 00C-3 48K DUAL FLOPPY 8" $3995.00

C-3* 23 MEG HARD DISK $9900 00

C-2-0EM 48K DUAL FLOPPY 8" $2699 00PLUS ALL SOFTWARE & PERIPHERALS

Mail order invited if machine can besent back to us for service. 220Vconversions available for systems-write for quote. Write for free cata-log. M/C. VISA. AX CARDS ACCEPTED

Aristo/Polks. 212 -279-9034

314 5TH AVE.(32 ST) NYC, N.Y. 100019 30/6-DAILY»THUHSTIL9»SUNDAY 11-5

s

\

Look to Aristo/Polks for rev

BUSINESS SOFTWARECP/M AND MODEL II COMPA"NEWLY ENHANCED VERSIO

MEDICAL MGMT SYSTEMS

riBLENS

5495$495S495$495$495$495$495$495$495$495$495$495$300

DENTAL MGMT SYSTEM

REAL ESTATE MULTI-LIST

INSURANCE AGENCY MGMT

LEGAL TIME ACCOUNTING

GENERAL LEDGER

ACCOUNTS PAYABLE

ACCOUNTS RECEIVABLE

PAYROLL PROCESSING

INVENTORY MANAGEMENT

WORD PROCESSING/NAD

DATABASE MANAGEMENT

HIGH-SPEED UTILITY SORT

NEWI LATEST CBASIC-2

$ 99$300$350

NEWI LATEST MBASIC 5.1

NEWI MBASIC COMPILER

• 'CP/M 2.0 FOR MODEL II

$170

. 55

COMPLETE SOFTWARE CATALOGCOMPLETE HARDWARE GUIDE

UNIVAIR, INC. 314-426

10327 LAMBERT INTL AIRPORTST. LOUIS, MISSOURI 63145 USAMASTER CHARGE/VISA CARDS O.K.

-1099 1

Circle 239 on inquiry card.

Circle 240 on inquiry card.

Circle 241 on inquiry card.

SURPLUS INVENTORY

NEW

$99

miii§jp

22 MHzBANDWIDTH

SOLID STATE MONITORS: Sylvania 12" B&W CRT, 22MHzvideo bandwidth. 800 line resolution! ASL Model C12AC8 OEMtabletop style without case. P4 phosphor, inputs ■ separate video,horz. & vert, pos, sync pulses at nominal TTL/CMOS levels. Anysweep rate. 10-20 KHz 115 VAC Simple TRS-80 hookup, add 2jumpers. With full mainl. manual incl. timing, schematics. TRS-80hookup etc. Used, re-checked, very clean, no burns $77. New,checked $93

2102 BONANZA: Prime, brand now static 1024x1 RAM.Fairchild F-2102-FPC, 3S0 ns. Sold in sleeves ol 25. 1-3 sleeves at$20 ea. 4-9 sleeves at $16 ea 10 sleeves and up at $10 per sleeve,that's prime, new 2102s at $ .40 m

'S100 CORE SALE: Brand new. tasted Ampex core See article"ITS TIME FOR CORE" (9/79 Kilobaud p. 34) which describes aneasily buill interface belween this core and an S-100 machine. Butignore the prices in (he article! Sale priced, including largedocumentation pkg. 8K boards $99 16K boards $230. Add $4 torschematics of core.

"OTHER SURPLUS BARGAINS: HARD DISKS, new w/man-ual $895. SHUGAHT SA800-1/801 floppies w/manual, new $425.Full ASCII KEYBOARDS $44 TOUCHTONE DECODERS $68.

TERMS: UPS Included 48 states except disk drives. UPS CODadd $1.25. VISA & MC add 4%. NJ add sales lax. Everythingguaranteed. Immediate shipment or immediate rotund. Phoneorders and questions are welcome.

' Write or call lor lull spec iheeli on specific Items.

ELECTRAVALUE INDUSTRIAL

P.O BOX 157-B r-,/1 Phone orders

MORRIS PLAINS, NJ 07950 cT vSA- are welcome-

77\ 201/267-1117

GAME DESIGN

Leading Coin-op AmusementGame company will consider useof YOUR pinball, video or othergame idea on a royalty, commis-sion or other basis. WRITE FORDISCLOSURE FORM BEFORESUBMITTING GAME IDEA.

Department BMA

P.O. Box 236

Bensenville, IL 60106

i Dial: 4Q2-987-3771

\mJJmniSl.

D

Hotline

YOU NEED CRISP, HIGH CONTRASTI BLACK-WHITE and VIVID COLOR

Ulpha-humerics/graphics ^>capabilities from your videomonitor if you want reallysuper-looking images fromyour computer!

AS SPECIALISTS IN VIDEOIMAGING ...we think wehave the right monitor ormodulator for your system.Our product line Includesthe popular "Micro-Verier"(OSI and Apple Inc. approvedUHF color modulator), a varietyof color and B-W monitors, colorcameras, B-W cameras, AudiotubcatTier kits and parts. FREECATALOG UPON REQUEST.Dealers welcomed. Well establishedprogram with over 900 dealers,

oo

:\t /////////1

47V Research u-Biinojoway DAKOTA city, NE.Gtnl

Circle 244 on inquiry card.

^CippfcZ II OrAPPLE II PLUS

16K$975.95, Extra 16KE.S. RAM installed$74.95. extra 32KE.S.RAM installed$148.95.

APPLE II HOBBY/PROTOTYPING CARD

PartNo.7907$14.95

REALTIME

100,000 DAY

CLOCK

MT. HARDWARE Dou-ble the utility of yourS-100 bus computerwith a real-time clockthat keeps time in100jiS increments forover 273 years. Pro-gram events for the en-tire period with real timeinterrupts...without de-railing the system. Main-tain a log of computerusage, time and datetransaction printouts,call up lists...virtually anyactivity where time is afactor. On-board batterybackup. MHPX004—$249.95

PET COMPUTER

SUPER MODEM

Orignate, RS-232 and20 mA compatable, Fullduplex, and half duplex,direct connect or a-coustic coupled, onboard power supply, car-rier detect light, DB25plug, 300 BAUD. Type103 compatable fre-quencies, Bare boardPart No. 2000. $19.95.Kit Part No. 2000A,$99.95.

16KEPR0M

JIM

Uses 270B EPROMS,memory speed selec-tion provided, ad-dressable anywhere in65K of memory, canbe shadowed in 4K in-crements. Board only$24.95 part no.7902, with parts lessEPROMs $49.95 partno. 7902A.

With 16K S. monitor -$ 795. Dual DiskDrive- $10 95

OPTO-ISOLATED

PARALLEL INPUT

BOARD FOR

APPLE II

There are B inputs thatcan be driven fromTTL logic or any 5 voltsource. The circuitboard can be pluggedinto any of the 8 socketsof your Apple II. It hasa 16 pin socket forstandard dip ribboncable connection.Board only$15.00. PartNo. 120, with parts$69.95. Part No. 120A.

VIDEO TERMINAL

IS* -l_m*i

16 lines, 64 columns •Upper and lower case

• 5x7 dot matrix • Se-rial RS-232 in and outwith TTL parallelkeyboard input < Dnboard baud rategenerator 75, 110,150, 300, 600, &1200 jumper select-able • Memory 1024characters (7-21L02)

• Video processor chipSFF96364 by Necu-lonic • Control char-acters (CR. LR -*, «-,T. i, non destructivecursor. CS, home, CL

• White characters onblack background orvice-versa • With theaddition of a key-board, video monitoror TV set with TVinterface [part no.107A) and powersupply this is a com-plete stand aloneterminal • also S-100compatible • requires+ 16. & -16 VDC at100mA, and BVDC at1A. Part No. 1000A$199.95 kit.

PARALLELTRIAC

OUTPUT BOARD

FOR APPLE II

This board has 8 triacs capable ofswitching 110 volt 6 amp loads [660 wattsper channel] or a total of 5280 watts. Boardonly $15.00 Part No. 210, with parts$119,95 Part No. 210A.

apple ii-::-

SERIAL I/OINTERFACE

Baud rate is continuously adjustable from 0to 30,000 • Plugs into any peripheralconnector • Low current drain. RS-232 inputand output • On board switch selectable 5 to8 data bits, 1 or 2 stop bits, and parity or noparity either odd or even • Jumper selectableaddress • SOFTWARE • Input and Outputroutine from monitor or BASIC to teletype orother serial printer • Program for using anApple II for a video or an intelligent terminal.Also can output in correspondence code tointerface with some selectrics. • Alsowatches DTR • Board only $15.00 Part No.2, with parts $42.00 Part No. 2A. assembled$62.00 Part No. 2C

8KEPR0MPICE0N

• Programs 2708's address relocation of each4K of memory to any 4K boundary • Power onjump and reset jump option for "turnkey"systems and computers without a front panel

• Program saver software in 1 2708 EPROM$25. Bare board $35 including custom coil,board with parts but no EPROMS $139, with 4EPROMS $1 79, with B EPROMS $219.

WAMECO PRODUCTS

With ELECTRONIC SYSTEMS parts

FDC-1 FLOPPY CONTROLLER BOARD willdrive shugart. pertek, remex 5" & 8" drivesup to 8 drives, on board PROM with powerboot up. will pperate with CPM (notincluded! PCBD $42.95

FPB-1 Front Panel. (Finally) IMSAI size hexdisplays. Byte or instruction single step,PCBD $42.95

MEM-1A BKxB fully buffered. S-100, uses2102 type RAMS.PCBD $24.95, $1 68 Kit

QMB-12 MOTHER BOARD, 13 slot, termi-nated, S-100 board only $34.95

$89.95 Kit

CPU-1 8080A Processor board S-100 with

8 level vector interrupt PCBD .. $25.95

$89.95 Kit

RTC-1 Realtime clock board. Two independ-ent interrupts. Software programmable.PCBD $25.95, $60.95 Kit

EPM-1 1702A 4K EPROM

card PCBD $25.95

$49.95 with parts less EPROMS

EPM-2 2708/2716 1BK/32K

EPROM card PCBD $24.95

$49.95 with parts less EPROMS

QMB-9 MOTHER BOARD. Short Version of

QMB-12. 9 Slots PCBD $30.95

$67.95 Kit

MEM-2 16Kx8 Fully Buffered 21 14 BoardPCBD $25.95, $269.95 Kit

Fully S-100 bus compatible including 16-bitmachines and 4 MHz processors. • Two soft-ware selectable Baud rates—300 Baud and ajumper selectable speed from 45 to 300 Baud.(110 standard). Supports originate and answermodes. • Direct-connect Microcoupler. ThisFCC-registered device provides direct accessinto your local telephone system, with none ofthe losses or distortions associated with acous-tic couplers and without a telephone companysupplied data access arrangement. • Auto-Answer/Auto-Call. The MICROMODEM 100can automatically answer the phone and receiveinput; it can also dial a number automatically. •Automatic Reset and Disconnect. • Softwarecompatible with the D.C. Hayes Associates80-103A Data Communications Adapter.Micromodem-DCHA32625—$379.95

TIDMA

Tape Interface Direct Memory Access • Recordand play programs without bootstrap loader (noprom) has FSK encoder/decoder for direct con-nections to low cost recorder at 1200 baud rate,and direct connections for inputs and outputs toa digital recorder at any baud rate • S-100 buscompatible • Board only $35.00 Part No. 112,with parts $110.00 Part No. 112A.

SYSTEM MONITOR

8080, B085, or Z-80 System monitor for usewith the TIDMA board. There is no need forthe front panel. Complete with documentation$12.95.

RS-232/TTYINTERFACE

PART && tfbiJ

This board has twoactive circuits, one con-verts RS-232 to 20 m A,the other converts 20mA to RS-232. Re-quires + 12 and -12volts. $9.95 Part No.600A Kit.

SERIAL I/O

. <§k$^x?:: ■":[

Four Serial I/O RS-232ports. S-100 Bus. Soft-ware or lumper selectablebaud rate (110. 300. BOO.1200,2400,4800,9600.19.2K), on board Xtal baudrate generator, Address-ing, switch selectable.Parity or no parity (odd oreven) switch selectable, 1or 2 stop bits, 5 to 8bits/character. Board onlyS29.95, Part No. 7908.With parts (kit) $199.95.Part No. 7908A.

S-100 BUSACTIVE TERMINATOR

Board only $14.95 Part No. 900. with parts$24.95 Part No. 900A

Tq Orrjgr ■ Mention part no. description, and price. In USA shipping paid by us for orders accompanied by check or money order.'' We accept C.O.D. orders in the U. S. only, or a VISA or Master Charge no., expiration date, signature, phone no.,shipping charges will be added. CA residents add 6.5% for tax. Outside USA add 10% for air mail postage and han-dling. Payment must be in U. S. dollars. Dealer inquiries invited. 24 hour order line [408] 448-0800

Send for FREE Catalog ... a big self-addressed envelope with 41* postage gets it fastest!

ELECTRONIC SYSTEMS m

B P. 0. Box 21638, San Jose, CA USA 95151

Circle 245 on inquiry card.

BYTE May 1980 295

HEX ENCODED KEYBOARD

Four- onboard LEDs indi-cate the HEX code gen-erated for each keydepression. The boardrequires a single +5volt supply. Board onlyS15.00 Part No. HEX-3,with parts $49.95 PartNo. HEX- 3A. 44 pinedge connector $4.00Part No. 44P.

T.V.TYPEWRITER

• Stand alone TVT

• 32 char/line. 16lines, modifications for64 char/line included

• Parallel ASCII (TTL)input • Video output

• 1K on board memory

• Output for computercontrolled curser •Auto scroll • Non-destructive curser •Curser inputs: up, down,left, right, home, EOL,EOS • Scroll up, down

• Requires +5 voltsat 1.5 amps, and -12volts at 30 mA • All7400. TTL chips •Char. gen. 2513 •Upper case only •Board only $39.00Part No. 106, withparts $145.00 PartNo. 106A

44 BUS MOTHERBOARD

Has provisions for ten44 pin (.156) connec-tors, spaced 3/4 of aninch apart. Pin 20 isconnected to X, and22 is connected to Zfor power and ground.All the other pins areconnected in parallel.This board also hasprovisions for bypasscapacitors. Boardcost $15.00 Part No.102. Connectors

$3.00 each Part No.44WP.

UART SBAUD RATEGENERATOR

• Converts serial toparallel and parallel toserial • Low cost onboard baud rate gener-ator • Baud rates:110, 150, 300, 600,1200. and 2400 •Low power drain +5volts and -12 voltsrequired • TTL com-patible • All characterscontain a start bit, 5to B data bits, 1 or 2stop bits, and eitherodd or even parity. • Allconnections go to a 44pin gold plated edgeconnector • Board only$12.00 Part No. 101,with parts $35.00 PartNo. 101 A, 44 pin edgeconnector $4.00 PartNo. 44P

RS-232/20mAINTERFACE

This board has twopassive, opto-isola-ted circuits. One con-verts RS-232 to20mA, the other con-verts 20mA to RS-232. All connectionsgo to a 10 pin edgeconnector. Requires+12 and -12 volts.Board only $9.95,part no. 7901. withparts $14.95 PartNo. 7901A.

ASCII TO CORRESPONDENCECODE CONVERTER

This bidirectional board is a direct replace-ment for the board inside the Trendata 1000terminal. The on board connector providesRS-232 serial in and out. Sold only as anassembled and tested unit for $249.95.Part No. TA10O0C

ASCII KEYBOARD

53 Keys popular ASR-33 format • RuggedG-10 PC. Board • Tri-mode MOS encoding• Two-Key Rollover ■ MOS/DTL/TTL Compat-ible • Upper Case lockout • Data and Strobeinversion option • Three User DefinableKeys • Low contact bounce • Selectable Par-ity • Custom Keycaps • George Risk Model753. Requires +5. -12 volts. $59.95 Kit.

ASCII KEYBOARD

TTL & DTL compatible • Full 67 key array

• Full 128 character ASCII output • Positivelogic with outputs resting low • Data Strobe

• Five user-definable spare keys • Standard22 pin dual card edge connector • Requires+5VDC, 325 mA. Assembled & Tested.Cherry Pro Part No. P70-05AB. $119.95.

COMPRINTPRINTER

Printing Characteristics: 225 characters/second (170 lines/minute) throughput • 9horizontal x 12 vertical matrix • 96 ASCIIcharacter set with upper and true lower case •80 characters/line • 5.8 lines/inchBuffer Memory: standard 256 bytes; •optional: 2,048 bytes (buffer memory optiondesignated as Model 912-2K), add $149.95.Paper Requirements: electrosensitive type(aluminum coated) • 8-1/2 inch width • 3.7inch max. (300 ft.) roll diameter.Model 912-S Interfacing: serial interfaceRS232 and 20 mA current loop • BAUD rates110. 150, 300, 600. 1200, 2400 and 4800are strap selectable.

Model 91 2-P Interfacing: parallel interface,IEEE^J88 and 8 bit parallel (strobe/ acknow-ledge). Model 912-S, Part No. CPIA, 32118$579.95. Model 912-P, Part No. CPIA, 32117$559.95.

T.V. INTERFACE

• Converts video toAM modulated RF,Channels 2 or 3. Sopowerful almost notuning is required. Onboard regulated powersupply makes this ex-tremely stable. Ratedvery highly in DoctorDobbs' Journal. Recom-mended by Apple •Power required is 12volts AC C.T., or +5volts DC • Board only$7.60 part No. 107.with parts $13.50 PartNo. 107A

SOROCIQ120

Upper/lower case dis-play • Numeric keypad& cursor keys • Pro-tected fields, Va inten-sity display • RS 232interface S. aux. port.IQ120-S799.95 •IQ140 Detachable key-board—$1199.95

RS-32/TTLINTERFACE

• Converts TTL to RS-232, and converts RS-232 to TTL • Two se-parate circuits • Re-quires -12 and +12volts • All connectionsgo to a 10 pin edgeconnector, kit$9.95 PartNo.232A 1OPinedgecon-nector $3.00 part No.10P.

TAPEINTERFACE

• Converts a low costtape recorder to adigital recorder • Worksup to 1200 baud* Dig-ital in and out are TTL-serial • Output ofboard connects to mic.in of recorder • Ear-phone of recorder con-nects to input on board

• No coils • Requires+5 volts, low powerdrain • Board only$7.60 Part No. 111.with parts$29.95PartNo. 111A

MODEM

• Type 103* Full or halfduplex • Works up to300 baud • Originateor Answer • Serial TTLinput and output • con-nect 8 n speaker andcrystal mic. directly toboard • Requires +5volts • Board only $7.60Part No. 109, with parts$29.95 Part No. 109A,

COMPUCOLOR II

a

m

tH

With reg. keyboardMOD3 BK $1595.95M0D4 16K $1695.95MOD 5 32K $1995.95Now includes $250more, worth of soft-ware and accessorieswith 101 key option add$134.95 with 117 keyoption add $179.95

DC POWER SUPPLY

• Board supplies a regulated +5volts at 3 amps., +1 2, -12, and -5volts at 1 amp. • Power required is8 volts AC at 3 amps., and 24 voltsAC C.T. at 1.5 amps. • Board only$12.50 Part No. 6085, with partsexcluding transformers $42.50Part No. 60B5A

Tq QrHgr • Mention part no. description, and price. In USA shipping paid by us for orders accompanied by check or money order.' We accept C.O.D. orders in the U. S. only, or a VISA or Master Charge no., expiration date, signature, phone no.,shipping charges will be added. CA residents add 6.5% for tax. Outside USA add 10% for air mail postage and han-dling. Payment must be in U. S. dollars. Dealer inquiries invited. 24 hour order line [408) 448-0800

Send for FREE Catalog ... a big self-addressed envelope with 41* postage gets it fastest!

ELECTRONIC SYSTEMS DePl B P' °- Box 21638,SanJose, CAUSA 95151

296 BYTE May 1980

Circle 246 on inquiry card.

TRS-80SERIAL I/O

• Can input into basic

• Can use LLIST andLPRINT to output, oroutput continuously •RS-232 compatible •Can be used with orwithout the expansionbus • On board switchselectable baud ratesof 110,150,300.600.1200. 2400. parity orno parity odd or even.5 to B data bits, and 1or 2 stop bits. D.T.R.line • Requires +5.-12 VDC • Board only$19.95 Part No. 8010,with parts S59.95 PartNo. 801OA, assembled$79.95 Part No. 8010C. No connectors pro-vided, see below.

cable S10 95 PareNo DB35P9

3' ribbon cablewith attached con-nectors Co lie TRS-80 and our serialboard SI 9 95 PartNo 3CAB40

COMPUCRUISE

$129.95; with cruise con-trol $169.95

THETELE5IS

VAR-80

INTERFACE

UNIT

j>

I

\

I

4 <

Q

E

if

For the TRS-BO withLevel II Basic • Provides8 outputs • Provides 8inputs • 2 ft. of inter-connecting cable w/ con-nector • Plugs directlyinto TRS-80 • Powersupply provided • As-sembled and tested.Part No. VAR80. Intro-ductory price $109.95.

GAME PADDLES& SOUND

'JZfr

Includes: 2 game pad-dles, interface, soft-ware, speaker, powersupply, full documen-tation including: sche-matics, theory ofoperation, and userguide; plus 2 games oncassette (Pong andStarshipWar). $79.95Complete Part No.7922C

DIGICOM DATAPRODUCTS INC.

Series 312Acoustic Coupler

300 BAUD Originate,Part No. AC3122,$219.95. 300 BAUDAnswer, Part No.AC3122, $219.95.300 BAUD Answer/Or-iginate, PartNo.AC3123.$229.95.

LIGHT-PENForYourTRS-SO

Your TRS-80 Light-Penis a carefully engineeredinstrument and with theproper care will givesatisfactory use andmany years of service.Part No. TRS80LP$24.95.

SYSTEMEXPANSION

fromLIMW Research

• Serial RS232C/20mA I/O • Floppy con-troller • 32K bytesmemory • Parallel print-er port • Dual cassetteport • Real-time clock

• Screen printer bus •Onboard power supply

• Software compatible

• Solder mask, silkscreen. PC board anduser manual. Part No.LNW80, $69.95.

DISKETTES

Box of 10. 5" $29.95,B" $39.95.Plastic box, holds 10diskettes. 5" - $4.50.8"-$6.50.

16K RAMS

For the Apple,TRS-80 or Pet $8each Part No. 4118/2117.

LEEDEXMONITOR

12" Black and White"12 MHz Bandwidth• Handsome PlasticCase-$139.00

S-100 INTERFACE

gv

AN S-100 bus Adapter—Motherboard for theTRS-80. Kit, Part No. HUH81DLXK, $295.95.Assembeled, Part No. HUH81DLXA, $375.95.

NOW!

A FULL SUPPORT SYSTEM

FOR TRS-80

• 32K of RAM • EPROM firmware • Diskcontrol • Data acquisition • Parallel I/O •Serial I/O • Plug into GPA's Motherboard.GPA's quality design includes • 6-44 pin edgeconnectors • +5V, -5V, +12V, -12V externalpower supply required • Active termination.The Motherboard, Part No. GPA80, is only$149.95.

TAKE ADVANTAGE OF

GPA-EXPANSION CARDS

FOR THE GPA80

Memory cards: Now with Fortran compilersavailable for your TRS-80. additional expansionmemory is a must! Card with sockets only, PartNo. GPA801 ,$119.95. Card with 16K of 4116Dynamic Ram, Part No. GPA802, $224.95.Card with 32K of 4116 Dynamic Ram. Part No.GPA803, $329.95. All cards come equippedwith sockets to accomodate 32K of Ram.EPROM firmware card. Put those valuablesubroutines in firmware. Don't waste timeloading and unloading tapes and disks. For 2708or 2716 EPROMS, Part No. GPA806, $79.95.Serial I/O card. Here's what you've beenasking for, a full serial terminal interface, withRS-232C or 20 mA. Current loop. Input/outputcapabilities. Part No. GPA807. $79.95.Parallel I/O Card. Control functions in theoutside world, monitor and store real timeevents. Two parallel output ports. Dip switchesselect ports (0-254). Part No. GPA808,$79.95.

FLOPPY DISKSTORAGE BINDER

Three-ring bindercomes with ten trans-parent plastic sleeveswhich accommodateeither twenty, five-inchor ten, eight-inchfloppy disks. Binder &10 holders $14.95 PartNo. 8800; Extra holders95C each. Part No. 800.

DIGITALCASSETTE

5 min. each side. Boxof 10 $9.95. Part No.C-5.

DISK JACKET7

Holds two 5-1 /4 inchdiskettes and will fitany standard three ringbinder.$9.95/10Pack.

TRENDCOMPRINTER

• 40 characters persecond • 4-7/16 inchwide thermal paper •Graphics (TRENDCOM100): 480 sevendotprint postions per line.TRENDCOM 100. PartNo.TRC0100.$495.95.TRENDCOM 200, PartNo.TRC0200,$375.95.Interface for TRS-80,PartNo.T80A$45.95.For Apple II. Part No.TRCAII, $75.95. ForPET. NO. TRCP2,$79.95. For Scoccerer,TRCSR1 $45.95.

SARGON: A ComputerChess Program

Features the complete program that won the1978 West Coast Computer Faire Tourna-ment. Part No. 00603 —TRS-BO Level II;Part No. 00604 — Apple II (24KI $19.95

SOUND EFFECTS AND MUSICFOR YOUR COMPUTER

SOUNDWARE is a complete system. It includesa speaker/amplifier unit with volume control,earphone jack, and connectors. It boastsexcellent tone quality yet is small and convenientto use. Add batteries, plug it in, and play. Oneyear warranty. SOUNDWARE package (in-cludes INTRO to SOUNDWARE programs)PET (8K), Part No. 20003, $29.95. TRS-80Level II (16K), Part No. 20002, $29.95.Compucolor II (8K), Part No. 20001, $39.95.INTRO to SOUNDWARE programs only PETand TRS-80, Part No. 20005. $14.95. Compu-color II Part No. 20006. $19.95.

Tr\ (VHar • Mention part no. description, and price. In USA shipping paid by us for orders accompanied by check or money order.' We accept C.O.D. orders in the U. S. only, or a VISA or Master Charge no., expiration date, signature, phone no.,shipping charges will be added. CA residents add 6.5% for tax. Outside USA add 10% for air mail postage and han-dling. Payment must be in U. S. dollars. Dealer inquiries invited. 24 hour order line [408] 448-0800

Send for FREE Catalog ... a big self-addressed envelope with 41* postage gets it fastest!

ELECTRONIC SYSTEMS DePtB P- °- Box 21638, SanJose, CAUSA 95151

Circle 246 on inquiry card.

Circle 247 on inquiry card.

H

CALIFORNIA COMPUTER SYSTEMS

16K RAM BOARD. Fully buffered addressable in 4Kblocks. IEEE standard for bank addressing 2114s.PCBD S 26.95 Kit 450 NSEC ....$249.95

PT-1 PROTO BOARD. Over 2,600 holes 4" regula-tors. All S-100 buss functions labeled, gold fingers.

PCBD $25.95

PT-2 PROTO BOARD. Similar to PT-1 except set-up to handle solder tail sockets. PCBD ...$25.95

CCS MAIN FRAME. Kit (S-100) $349.95

APPLE EXTENDER. Kit $22.95

APPLE IEEE INSTRUMENTATION INTERFACEKIT 7490. Kit $275.00

ARITHMETIC PROCESSOR FOR APPLE 7811A.Kit .5350.00

APPLE ASYNCHRONOUS SERIAL INTERFACE7710A. Kit $89.95

APPLE SYNCHRONOUS SERIAL INTERFACE

7712A. Kit $89.95

ALL OTHER CCS PRODUCTS AVAILABLE

S£i7?

PB-1 2708 & 2716 Programming Board with pro-visions for 4K or 8K EPROM. No external suppliesrequire textool sockets. Kit $129.95

CB-1A 8080 Processor Board. 2K of PROM 256BYTE RAM power on/rest Vector Jump Parallelport with status. Kit $129.95 PCBD : $27.95

VB-3 80x55 VIDEO BOARD.

Graphic included TBD

IO-4 Two serial I/O ports with full handshaking20/60 ma current loop: Two parallel I/O ports.Kit $130.00 PCBD $26.95

VB-1B 64 x 16 video board, upper lower case Greekcomposite and parallel video with software. S-100.Kit $125.00 PCBD $26.95

CB-2 Z80 CPU BOARD. Kit $185.95

Kit ......

AIO APPLE SERIAL/PARALLEL

$159.95

ALL OTHER SSM PRODUCTS AVAILABLE

W7T7C

/nc. WAMECO INC.

FDC-1 FLOPPY CONTROLLER BOARD will driveshugart. pertek, remic 5" & 8" drives up to 8 drives,on board PROM with power boot up, will operate

with CPM'M (not included). PCBD $42.95

FPB-1 Front Panel. IMSAI size, hex displays. Byte,

or instruction single step. PCBD $47.50

MEM-1A 8Kx8 fully buffered, S-100. uses 2102

type rams. PCBD $25.95

QM-12 MOTHER BOARD, 13 slot, terminated, S-100

board only $34.95

CPU-1 8080A Processor board S-100 with 8 level

vector interrupt. PCBD $26.95

RTC-1 Realtime clock board. Two independent in-terrupts. Software programmable. PCBD S23.95EPM-1 1702A 4K Eprom card. PCBD $25.95

EPM-2 2708/2716 16K/32K EPROM CARD.PCBD . . ... $25.95

QM-9 MOTHER BOARD. Short Version ol QM-12.

9 Slots. PCBD .... $30.95

MEM-2 16Kx8 Fully Buffered 2114 Board.

PCBD $26.95

PTB-1 POWER SUPPLY AND TERMINATOR BOARD.PCBD $25.95

IOB-1 SERIAL AND PARALLEL INTERFACE.2 parallel, one serial and cassette.

PCBD $26.95

2708 $9.49 2114 (200 NS) low pwr.

2114 (450 NS) low pwr. 5.99 $6.99

im

Kf ADDRESS AND PHONE ^ ^^

P.O. Box 955 • El Granada, CA 94018

Please send for IC, Xistor and Computer parts list

MAY SPECIAL SALEON PREPAID ORDERS

(Charge cards nol included on this offer)

IO-4 LAYOUT REJECTS. One simple change.

PCBD $20.00

8Kx8 RAM. Fully buffered. 450 NSEC assembledand tested $99.99

MIKOS PARTS ASSORTMENTWITH WAMECO AND CYBERCOM PCBDS

MEM-2 with MIKOS =7 16K ram

with L2114 450 NSEC . $249.95

MEM-2 with MIKOS =13 16K ram

with L2114 250 NSEC $279.95

MEM-1 with MIKOS =1 450 NSEC 8K

RAM $119.95

CPU-1 with MIKOS r2 8080A CPU $ 94.95

QM-12 with MIKOS -A 13 slot mother

board S 89.95

RTC-1 with MIKOS =5 real time clock $ 54.95EMP-1 with MIKOS -10 4K 1702 less

EPROMS S 49.95

EPM-2 with MIKOS =11 16-32K EPROMS

less EPROMS . $ 59.95

QM-9 with MIKOS =12 9 slot mother

board $ 79.95

FPB-1 with MIKOS =14 all parts

for front panel $134.95

MIKOS PARTS ASSORTMENTS ARE ALL FACTORY MARKEOFARTS. KITS INCLUDE ALL PARTS LISTED AS REQUIREDFOR THE COMPLETE KIT LESS PARTS LISTED. ALL SOCK-ETS INCLUDED.

VISA or HASTERCHARGE. Sent! account number, interbank num-ber, expiration date and sign your order. Approx. postage willbe added. Check or money order will be senl post banl in U.S.II you are nol a regular customer, please use charge, cashier'scheck or postal money order. Otherwise there will be a two-week delay foi checks to clear. Calif, residents add G°o tax.Money back 30-day guarantee. We cannot accept returned IC'sthat have been soldered to. Prices subject to change withoutnotice. 510 minimum order. St.50 service charge on ordersless than $10.00.

thispublication

is available

in microform

piease send me additional information. University Microf ilms International

Name

Institution

Street

City

State

300 North Zeeb Road

Dept. P.R.

Ann Arbor, Ml 48106

U.S.A.

Zip

18 Bedford RowDept. P.R.London, WC1R4EJEngland

298 BYTE May 1980

nm micro

BUSINESS WORLD

Immediate response to your orders (verbal or written). Phone (213) 371-1660

CromemCO System Three FEA TURES . .

• Z-80A Micro Processor • 64K RAM

• Dual 8" Double Sided Disk Drive easily expan-dable to 4 Drives • RS232 and Printer Interface.

CALL FOR OUR PRICE

CrotnentCO System Two FEATURES . . .

• Z-80A Micro Processor • 64K RAM

• Wangco Drives • RS232 and Printer Interface.

CALL FOR OUR PRICE

saimvo g» MONITOR

A SuperbBlack andWhite TVMonitorthat canbe usedwith mostComputers

OUR

V

PRICE $185

Apple IIpersonalcomputer.

We have acomplete stockof differentSoftware forthe Apple II

All Apple and Apple related products...20-25% OFF list price

Texas Instruments 11~!7"/4 Home Compute

The TI-99/4 gives you an unmatched combination offeatures, including: • Powerful TI-BASIC-buifloating point BASIC. • Up to 72K total memory capacity— 16K RAM (Random Access Memory). 26K ROM (Re;Only Memory), plus up to 30K ROM in Tl's Solid SCommand Modules. • 13" color monitor included• Revolutionary Solid State Speech'"Synthesizer (optional) Our Price $999

ZENITH DATA SYSTEMS:

Smart Video Terminal

Impact Printer

TheRaperTiger

This low-cost printer hasthe capability of printerstwice it's price. Ideal for use \with small computers

w/graphics OUR PRICE $1050.

Z-89 Computer System:

includes: Z19 Display, a built in5%" Floppy Disk, 2 serial ports,and 16K of memory. 2295.0048K Memory version 2595.00

Z-19 has aZ80 Microprocessor,Numeric Keypad and 8 functionkey $895.00

DYSAN DISKETTES

THE CADILLAC OF THE FLOPPY DISKS

AT LOW LOW PRICES

8" (Box of 10)37401/1 sgl side/sgl density $4.50 ea.

8" (Box of 10) 3740/1D sgl side/dbl density $6.95 ea.

5" (Box of 5):

104/1 Soft Sector or 107/1 10 Sectorsor 105/1 16 Sectors $4.50

ATARI 800

PersonalComputer System

Packed with: Computer Console, Basic

Language Card, Education System

Master Cartridge, Cassette Recorder, TV

Modulator, 8K Memory (expandable to

48K), Power Supply & all Books and

Manuals $849.99

AT/ID I /inn Personal ComputerfllHnl *HJU System for lessPacked with: Computer Console, BasicLanguage Cartridge, Power Supply, TVModulator, and all Books andManuals $524.99

ATARI Program Recorder 69.99

ATARI Software, Roms, Cassettes 25% otf list price

ATARI Expansion Memory 8K Module 99.99

16K Module 169.99

System B is a Z-80 based microcom-puter with over 630,000 characters of on-line storage and is capable of handlingstandard accounting or special com-putations of any small business or largecompany department — even scientificcalculations in a technical environment.Call for Our Price

Plastic Floppy Disk HolderPlastic Floppy Disk Holder

(up to 10) 8" $3.95(up to 10) 5M $3.25

16K RAM setof84116's 250 ns or better $65.00

Prices subject to change without notice.

VISA and MASTER CHARGE WELCOME. Allow.2 weeks for cashierscheck to clear, 4 weeks for personal checks. Add 2% for shipping andhandling. Calif, residents add 6% sales tax. (Sorry, no COD.)

U.S. and International dealer inquiries invited.

Copyright 1980 • MICRO Business WORLD circ|e 249 on inquiry card.

MICRO

BUSINESS WORLD

15818 Hawthorne Boulevard

Lawndale, California 90260(213) 371-1660.

_____ SAVE!!

- TPQ>fin

SSgaaaSgaaff^

I

10,15 *Percentand More!

on computers, peripherals, software and other Radio Shack® products.

NO ONE CAN GIVE YOU A BETTERDEAL ON TRS-80 COMPUTERS!!

OUR Radio Shack® Merchandise is New :§

and covered by Radio Shack® War- i:j:

rantiesWE PAY Domestic U.P.S. Shipping & In

surance on minimum ordersNO TAXES are collected on out-of-state :•:

ShipmentsTOLL FREE Order NumberOPEN 8:00 a.m. to 6:00 p.m., Central Time, |

Monday through Friday; 9:00 a.m. to ji;

6:00 p.m., Saturday 8

Offered Exclusively By

Pan AmericanElectronics

Radio /haelt

AUTHORIZED SALES CENTER

INCORPORATED

1117 CONWAY

8

VISA'

MISSION, TEXAS 78572TOLL FREE ORDER NUMBER 800/531-7466TEXAS AND MAIN TELEPHONE NUMBER 512/581-2765

Sfrffs^ffflfi^^

ssssssssssb^-S

WAMECO

THE COMPLETE PC BOARD HOUSEEVERYTHING FOR THE S-100 BUSS

INTRODUCTORY SPECIALIOB-1 SERIAL/PARALLEL INTERFACE BOARD

* TWO PARALLEL DATA PORTS PROGRAMMABLE USING AN 8255 WITH SEPARATEHANDSHAKING.

* ONE SERIAL PORT USING AN 8251 WITH PROVISIONS FOR PARITY, STOP BIT ANDCHARACTER LENGTH. BAUD RATES 110 TO 9600 BAUD. OUTPUTS RS232, TTLAND CURRENT LOOP.

* KANSAS CITY STANDARD CASSETTE INTERFACE, 300 BAUD FOR USE WITH THESERIAL INTERFACE.

* STATUS MAY BE ROLLING SOFTWARE OR VECTURED INTERRUPTS.PCBD

.$31.95

KIT TO BE ANNOUNCED LATER.

FUTURE PRODUCTS: 80 CHARACTER VIDEO BOARD.Z-80 CPU BOARD WITH RAM, ROM AND PROGRAMMABLE VECTOR INTERRUPTS.

DEALER INQUIRIES INVITED, UNIVERSITY DISCOUNTS AVAILABLE

AT YOUR LOCAL DEALER

MOST PRODUCTS FOR IMMEDIATE SHIPMENT. NO

WEEK DELAYS REQUIRED FOR OTHERS.

_ pHONE

N WAMECO. INC., P.O. BOX 877

wmc/

inc.

455 PLAZA ALHAMBRA • EL GRANADA, CA 94018 • (415) 726-6378

300 BYTE May 1980

Circle 251 on inquiry card.

NEW PRODUCTS!

Super Color S-100 Video KMS99.95 Elf II Adapter Kit $24.50

Expandable lo 256 x 192 high resolution colorgraphics. 6847 with all display modes computercontrolled Memory mapped. IK RAM expanda-ble to 6K. S-100 bus 1802. 8080. 8085.Z80 etc.

Gremlin Color Video Kit S59.95

32 x 16 alpha/numerics and graphics; up to 8colors with 6847 chip; 1K RAM at EO00. Plugsinto Super Elf 44 pin bus. Not expandable to highresolution Graphics.

Plugs into Elf II provicing Super Elf 44 and 50 pinbus plus S-100 bus expansion (With Super Ex-pansion). High and low address displays, stateand mode LED s optional $18.00.

1802 16K Dynamic RAM Kit S149.00

1802/S-100 expandable to 32K. Hidden refreshw/clocks up to 4 MHz w/no wait states Addl. 16KRAM $79.00.

Quest Super Basic

Quest the leader in inexpensive 1802 systemsannounces another first. Quest is the first com-pany worldwide to ship a full size Basic for 1802systems. A complete function Super Basic byHon Cenker including floating point capabilitywith scientific notation (number range ±. 17E3B).32 bit integer • 2 billion; Multi dim arrays; Stringarrays; String manipulation; Cassette I/O, Saveand load, Basic, Data and machine language pro-grams; and over 75 Statements, Functions andOperators.

Easily adaptable on most 1802 systems. Re-quires 12K RAM minimum for Basic and user

programs. Cassette version in stock now. HOMversions coming soon with exchange privilegeallowing some credit for cassette version.Super Basic on Cassette $40.00

Tom Pittman's 1802 Tiny Basic Source listingnow available. Find out how Tom Pittnian wroteTiny Basic and how to get the most out ol II.Never offered before. S19.00

S-100 4-Slot Expansion S 9.95

Super Monitor VI.I Source Listing $15.00Coming Soon; Assembler, Editor. Disassem-bler, DA/AD, Super Sound/Music. EPROMprogrammer, Stringy Floppy Disc System.

RCA Cosmac Super Elf Computer $106.95

Compare features before you decide to buy anyother computer. There is no other computer onthe market today lhal has all the desirable bene-fits of the Super Ell 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 Elf 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 before, 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 loconned lo 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 keysplus 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 tor 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 anduniversities are using the Super Elf as a courseof study. OEM's use it lor training and R&DRemember, other computers only offer Super Elffeatures at additional cost or not at all Comparebefore you buy. Super Ell Kit S106.95, Highaddress option 58.95, Low address option$9.95. Custom Cabinet with drilled and labelledplexiglass front panel $24.95. Expansion Cabinetwith room for 4 S-100 boards S41.00. NiCadBattery Memory Saver Kit S6.95. All kits andoptions also completely assembled and tested.Questdata. a 12 page monthly software pub-lication for 1802 computer users is available bysubscription for S12.00 per year. Issues 1-12bound S16.50.

Tiny Basic Cassette $10.00, on ROM S38.00,original Elf kit board S14.95. 1802 software;Moews Video Graphics $3.50. Games and Music$3.00, Chip 8 Interpreter $5.50.

Super Expansion Board with Cassette Interface S89.95

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 ol low power RAM fully address-able anywhere in 64K with built-in memory pro-tect and a cassette interface. Provisions havebeen made for all other options on the sameboard and it fits neatly into the hardwood cabinetalongside the Super Elf. The board includes slotslor up to 6K of EPROM (2708. 2758, 2716 or Tl2716) and is fully socketed. EPROM can be usedlor 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, (relocatible cassette file)another exclusive from Quest. It includes registersave and readout, block move capability andvideographics driver with blinking cursor. Breakpoints can be used with the register save featureto isolate program bugs quickly, then follow withsingle step. The Super Monitor is written with

subroutines allowing users to take advantage ofmonitor functions simply by calling them up.Improvements and revisions are easily done withthe monitor. If you have the Super ExpansionBoard and Super Monitor the monitor is up andrunning at the push ol a buttonOther on board options include Parallel Inpuland Output Ports with full handshake Theyallow easy connection of an ASCII keyboard to theinput port RS 232 and 20 ma Current Loop lorteletype or other device are on board and if youneed more memory [here 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 S3.85. RS 232 $4.50,TTY 20 ma l/F $1.95, S-100 $4.50. A 50 pinconnector set with ribbon cable is available atS15.25 for easy connection between the SuperElf and the Super Expansion Board.Power Supply Kit for the complete system (seeMulti-volt Power Supply below).

TERMS: S5.00min. orderU.S. Funds. Calif residents add6% tax.BankAmericard and Master Charge accepted.Shipping charges will be added on charge cards.

Same day shipment. First line parts only.Factory tested. Guaranteed money back.Quality IC's and other components at fac-tory prices.

INTEGRATED CIRCUITS

Moom

MOONMQ2N740-1N7409N74 ION7-11-1M74201)7422N7430N7442N7445N714 7N7448N7450N7174117475117485N7489N7490N7192N7493N7195N74IDON74107N74T21N7JI23H7412SN74l45r)74150N74I5IN

741G3N 8

74174N 9

7*17514 9

7-H90N 1 l

74192N B

74193N S

74221N 2 D

7-=29BN 1 6

74365N 6

74365N 6

74367N 6

74LSDB TTL

74LS00M 3

741S02N 3

74LSQ4N 3

74LS05N 3

74LS08N 3

74LS10N 3

74I.S13N 5

74L514N 1 1

74LS20N 3

74LS22N 3

74LS28N 4

74LS30N 3

74LS33N 7

74LS3BH 5

74LS74N 1 2

741S75H 1 O

74LS90N 8

74.S93N 7

741.S95N I t

MLS107N 4

74.S112N 4

741S155N B5

74LS190N I DE

741S22IN 1 95

741S258N 67

741S367N 1 35

LINEAR

CA3045 90

CA3046 I TO

CA3081 1 80

CA3082 1 90

CA3089 2 95U1301AN AH 35

LM305H 87

LM3D7N 35

LM308N 89

LM309K 1 50

LM3HHN 90

LM3I7TK 3 75

LM323K-5 5 95

LM320K-12 1 50

LM320K-15 1 50

LM3201-5 I 60

LM320T-8 1 60

LM320T-12 1 50

LM320T-15 I 60

LM324N I 15

LM339N 1 55

LM340K-5 1 35

LM340K-8 1 35

LM340K-12 1 35

LM340K-15 135

LM340K-2J I 35

LM34DT-5 1 25

LM340T-B I 25

LM340T-12 1 25

LM340T-15 1 25

LM340M8 1.25

LM340T-24 1 25

LM343H 4 50

LM350 7.50

LM370 1 15

LM377 3 00

LM379 5 00

I.M380N ! 00

LM381 1 60

LM3B2 1.60

LM703H 40

LM709H 28

LU723H.M 50

LM733N 67

LM741CH 35

LM741N 32

LM747HN 75

LM748N 35

LM1303N 1 75

LU1304 1 10

LM1305 1 27

LM1307 2 00

LM1310 2 75

LM1458 47

C0402ICD4022CD4023CD-I 024C04025CD4026CD4D27CD402BCD4029CD4030CD4035CD 4040CO4042GO4043C04044

CO 4 046CU4049CD-1O50CD40S1CD-'.OGO

cwm

CI MOPSCD4BG9CD4O70CD407ICD4072CD4073CDJ075CD40/6CD40HCO4081CD4082CD4I16CD4490CD 4 507C0450SCD45I0CD4511C04515CD45I6C04518

Box 4430X, Santa Clara, CA 95054Will calls: 2322 Walsh Ave.^(408) 988-1640

ELECTRONICS

.'IlKA-l

21078-6 3 75

3111-1 3 75

2112-2 3 95

2114L 300ns 7 40

4116 200ns 9 50

B41I6 200ii5 64 00

2513B 6 30

MM5262 40

MM52B0 3 00

MM5320 9 95

MM5330 5 94

P0411D-3 4 00

P0411D-4 5 00

l'51()1L 895

4200A 9 99

B2S25 2 90

91L02A 1 50

HO0I05-5 6 95

MM57100 4.60

GIAY3S5O0-I 9 95

MCM6675IA 9 95

936B 3.50

410P 10 00

416 16 no

CLOCKS

MM5311 5 50

MM5312 3 90

MM5314 3 90MM5369

MM 5,141

MM:fll,3 7 95

CT70O1 5.BO

CT7010 8 95

CT7015 8 95

MttM7bAA.N 3 90

MU5375AGN 4 90

lype 012

14 45

740 00

CONNECTORS30 pin edge 2 50

44 pin (Mine 2 75

100 pi" edge 4 50

100 pm eilgu WW 5 25

IC SOCKETSSolder Tin Low ProfilePIN tUP PIN 1UPB 15 22 30

20 29 40 57

RESISTORS t. wan 5S

10 pei lype 03 1O00 pn25 pet type 025 350 pice ,».100 per lype 015 5 per type 6 75

'■) waft 5°c per type 05KEYBOARDS

56 kay ASCII keytjoarrl kit S67 50

Fulk nssemdled 77 50

'>'( i.uy ASCII keyDoard kil 60 00

Fully assembler} 70 00

Enclosure 14 95

Meial Enclosure 29 95

LEDSRed 1018 IS

fili:n> Yellow T01H 20

Ciuirii. (liangc. Yellow Jumbo 25

Cllplile LED Mounllng. Clips 8/S1 25(speedy red amber, green yellow, clear)

CONTINENTAL SPECIALTIES in slockComplete tme of Dreaduc.nd lest equipMAX- nut 8 digi! Freq. Ctr. S17B.95

WIRE WRAP LEVEL 3

14 32 24

16 33 28 1 0

LM1BC

1812

LM1BB9 3 00

LM2HI 1 75

LM2902 1 50

LM3900N 60

LM3905 1 75

LM3909N 89

MCI 458V 50

NE540H 3 75

NE550N 1 00

NE555V 39

NE556A 85

NE565A 1 00

NE566V 1 50

NE567V 1 00

NE570B 5 00

78L05 GO

7BL00 60

7BM05 85

751OB I 75

7549JCN 50

75492CN 55

75494CN 89

A to 0 CONVERTER

B038B 4.50

8700CJ 13 95

8701CN 22 00

8750CJ 13.95

LD130 9 95

9400CJV;F 7 40

ICL7103 9 50

ICL7107 14 25

CMOS

CD3400I Fair

CD4000

CD4O01

CD4002

CD40.06 I

CD40O7

CD4008

CD4009

CD4010

CD401!

CD4012

CD4013

CD4014 1

CD4015 I

CD4016

CD40I7 1

C040IB

CO 1019

CD402O 1

CD4520

t 02

7205

T -■■■

CD4527

1'.;■':.''■(;■,

[iS'!^hO;

3 75

CD4555

1 10

MM53104

?5D

CO 40192

3 DO

MICROPROCESSOR

6504

BOBOA

74C1GD

1 44

/4C922

5.50

18G1P

11 50

BD95

65

4 Wit5M

10 MHf 4 25

18 MHz 3 90

20 MM* 3 90

32 MHt 3 90

32768 Hz 4 00

1 843? MM; 4 503 5795 MHI I 20

2 0100 Wit f 952 097152 Wit 4 50

2 J57G MM? 4 50

3 7/C'R MH/ 4 50Mil-Mi MM/ 4 50', :Ha Mil; 4 505 7M3 MM; 4 50fi bb3( Mil; 4 5014 318IB MX; 4 2518 432 MHl 4 5022 IIB4 MH; 4 50

KEYBOARD ENCODERS

AYS-:'37(i S12 50

AY:, 3Gl)fl 17 95

AY5-9100 10 50

AY5 92O0 16 50

74C922 5 50

74C323 5 50HD0T6M

SPECIAL PRODUCTSMM5865 5lop*alcn Timer

Mdh 10 po spec 9 00

PC acua 7 50

i 23 Switches Man: Pushbutton 27

3pos slide 25

Encoder HD0ifi5-5 G 95

Paralrnmcs 100A Logic

Anatyiti Kit S224.DO

Model 10 Trigger

EipanCer Kn S229 DO

Model 150 Bus

GubDer Kit S3C9 00

Sinclair 3': Digil

Mullimeler S59.95

Clock Calendar Kit S23 95

2 5 MHl Frequency

Counier Kii S37 SO

30 MHl Frequency

Counter Kii $47.75

12 Von

uri:.v,rr:

? 6V CI 600 n-12V 250 ma wall plug12V CT 250 ma wall plug24V CT 400 ma

1 2 amp wall plug

12V 6 ai12V 580 ft

II plug

6,95

B09BBT098T10

ST20

5 50

8T23

3 10

8T24

3 50

8T25

3 20

8126

1 69

8128

2 75

8197

1 69

8T9B

1 69

MOSjMEMORY

2ioi-i :

2102-1

2102AL-J '

2102AN-2L '

UART.'FIFOAY5 1013AY5-10I4

2513U upper i

2708

271611

2716 Intel

8 7716 Intel

773?

2758

B741A

8748

874B-B

8755A

NB2S23

NB7S123

ise6 957 7524 5034 95

.!(.., '

gi QO22 5085 0075 00,-u QO65 00

0 Connectors RS232DB2SP 2 95

DB25S 3.95

Cover 1.50

HS232 Coining -:t: f> 50DE9S 1 95

DAI5P 2 10

DA15S 3.10

HickukS'jOiqilLEDmullimeler 89.95

Stopwatch Kii 26.95

Aula Clock KII 17.95Nol a Cheap Clock KMS14.95

lF:clutlt!Si:i'i'C,;tiiiir]i.'icep!ca^e ^-PCboarils 5 50'LEO Displays 5314 clockchip iiansloimer. all

10 15 VAC 8.16 VA wall plug 9 71DISPLAY LEDS

MANi CA 270 2 9

MAN3 CC 125 3

MAN72/74 CA/CA 300 1

DL704 CC 300 I

OL707TJL707H CA 300 1

DL727;72B CA-CC 500 1

nents a

Only S21.95Car.eS1I.758K1BK Eprom Kil

(lest PROIVS, SH9 00Motherboard 539 00

EilenOtr Board S3 99

DL 74 7 750

DL750

FN0359

INnVili 507

rrjuiii.'i :,io'NIlKlUlSII?3 Higil Buhule

DG8 FluorescenlDGlOFltorescenl5 digit 14 pin displa>10 iiigi: display7520 Claire* pboiocelisTIL3II Hw

MAN3640 CC

MAN461D CA

MAN464D CC

MAK4710 CA

MAK4740 CC

WAN6540'.'■Mi: '■MANfi74n

CA/CC 600 1 95

CC 600 1 95

CC 357 70

CC'CA 500 ' 35

CC/CA 500 90

CC'CA 800 2 70

CC 56 2 95CA 60 1 35CC 60 i 35

MA1D02AMA1002EMA10I2A107P3 Irani

ROCKWELL AIM 65 Computer

6502 based single board with lull ASCII keyboardand 20 column thermal printer. 20 char, alphanu-meric display, ROM monitor, fully expandable.$375.00. 4K version S450.00, 4K Assembler$85.00, 8K Basic Interpreter S100.00.

Special small power supply lor AIM65 assem. inframe S49.00. Complete AIM65 in thin briefcasewith power supply S485.QD. Molded plasticenclosure to fit AIM65 plus power supply $47.50.Special Package Price: 4K AIM, 8K Basic, powersupply, cabinet S599.00

AIM65/KIM/VIM/Super Elf 44 pin expansionboard; 3 female and 1 male bus. Board plus 3connectors $22.95.

AIM65/KIM/VIM I/O Expansion Kit: 4 parallel and2 serial ports plus 2 internal limers $39.00. PROMprogrammer for 2716 $150.00.

Multi-volt Computer Power Supply

8v 5 amp. - 18v .5 amp. 5v 1.5 amp. -5v.5 amp. 12v .5 amp. - 12 oplion. »5v. *12vare regulated. Kit S29.95. Kit with punched frameS37 45, S4.00 shipping. Kil of hardware $14.00.Woodgrain case $10.00. S1.50 shipping

PROM Eraser win erase 25 proms in

15 minutes. Ultraviolet, assembled $37.50Safety switch/Timer version 569.50

60 Hz Crystal Time Base Kit $4.40

Converts digital clocks from AC line frequencyto crystal time base. Outstanding accuracy.

NiCad Battery Fixer/Charger Kit

Opens shorted ceils that won'l hold a chargeand then charges them up, all in one kit w/fullparts and instructions. $7.25

LRC 7000 +Printer S389.00

40/64 column dot malrix impact, std. paperInterface all personal cemputers

Televideo Terminal $845.00

102 key. upper, lowercase. 10 Baud rates 24 x 80char, microprocessor cont. edit. cap.Interlude II Terminal $874.00Super BrainFloppy Disk Terminal $2895.00

79 IC Update Master Manual S29.95

Complete IC data selector. 2500 pg. master refer-ence guide. Over 50,000 cress references. Freeupdate service through 1979. Oomestic postageS3.50. No foreign orders.

S-100 Computer Boards

8K Static RAM Kit S135.00

16K Static RAM Kit 265.00

24K Sialic RAM Kit 423.00

32K Static RAM Kit 475.00

16K Dynamic RAM Kit 199.00

32K Dynamic RAM Kit 310.00

64K Dynamic RAM Kil 470.00

Vided Interlace Kit 5129.00

Video Modulator Kit $8.95

Convert TV set into a high quality monitor w/oaffecting usage. Comp kit w/full instruc.

Digital Temp. Meter Kit $34.00

Indddr and outdoor. Switches back and forth.Beautiful. 50" LED readouts. Nothing like itavailable. Needs no additional parts for com-plete, full operation. Will measure -100°to+ 200°F, tenths of a degree, air or liquid.Beautiful woddgrain case w/bezel $11.75

FREE: Send for your copy of our NEW 1980QUEST CATALOG. Include 28c stamp.

Circle 252 on inquiry card.

BYTE May 1980 301

Circle 253 on inquiry card.

computerproducts, inc.

11542-1 KNOTT ST.

GARDEN GROVE,

CA 92641

(800) 854-6411

(714)891-2663

2708's

450NS.

100 PIN-GOLD

IMSAI CONN.SOLDERTAIL

$£. iD each

10for$2.60

ea.

MICROBYTE16K STATICRAM BOARD

•S-100 COMPATIBLE•4K BANK ADDRESSABLE•EXTENDED MEMORYMANAGEMENT• NO DMA RESTRICTIONS•ASSEMBLED & TESTED•4MHZ OPERATION

$250.00 each

CATALOG

AVAILABLE

CALL OR WRITE

ORDERING INFO

4116's—200ns

ADD-ON MEMORY FOR: TRS-80,APPLE, HEATH, EXIDY, ETC.

8 tor $55.00

16 for $11 0.00

8.50 each8/S60.00

8251

2716's

450 NS5-VOLTONLY

$35.00

REGULATORS

320T-5. .320T-12.340T-5..340T-12.78405 . .

MICROBYTE

32K STATICRAM BOARD

• IEEE/S-100 compatible•4K bank addressable to

any 4K slot within a64K boundary

• On board 8-bit outputport

• No DMA restrictions

• 4 Hmz operation

LO-PRO SOCKETS

1-99 100 Up

14 PIN

.11

.10

16 PIN

.12

.11

18 PIN

.16

.14

20 PIN

.24

.22

24 PIN

.31

.29

28 PIN

.35

.31

40 PIN

.42

.39

NAME, ADDRESS, PHONE

SHIP BY: UPS OR MAIL

SHIPPING CHRG. ADD

$2.00 UP TO (5) LBS.

TERMS

WE ACCEPT CASH,

CHECK, MONEY ORDER,

VISA & MASTER CHARGE

CREDIT CARDS.

(U.S. FUNDS ONLY)

TAX: 6% CALIF. RES.

LOBO INT'L.

APPLE II

DISK DRIVE(1)SHUGART400W/CABLE

$395.00

•WITH OPTIONALINTERFACE CARD

$495.00

CENTRONICS

PRINTERS

MODEL #703

180 CPS BI-DIRECTIONALLOGIC SEEKING PRINTERWITH 132 COLUMNCARRIAGES, ELECTRONICTOP OF FORM, VFU &CENTRONICS STANDARDPARALLEL INTERFACE

$1995.00

TRS-80 DISK DRIVE

LOBO INT'L

SA800

SINGLE-SIDED/DBL. DENSITYSHUGART8"FLOPPY DISKDRIVE, INSTALLEDW/PWR. SUPPLY

(1) DRIVE INSTALLED

$775.00

(2) DRIVES INSTALLED

$1250.00

•UP TO 218K BYTES•SINGLE/DOUBLE DENSITY•SOFT SECTOR•25 MSEC. ACCESS•SOFTWARE COMPATIBLE•ASSEMBLED & TESTED

$395.00 each

100/$9.00

BUILD YOUR OWN LOW COSTMICRO-COMPUTER

POWER SUPPLIES

FOR S-100 BUS, FLOPPY DISCS, ETC.

POWER TRANSFORMERS (with mounting brackets)

ITEMNO.

USED INKIT NO.

PRI. WINDINGTAPS

SECONDARY WINDING OUTPUTS2x8 Vac 2x14 Vac 2x24 Vac

SIZE

W x D x H

UNITPRICE

T1T2T3T4

OV, 110V, 120VOV, 110V, 120VOV, 110V, 120VOV, 110V, 120V

2x7.5A

2x12.5A

2x9A

2x4A

2x2.5A2x3.5A2x2.5A

2x2.5A2x3A

3%"x35/8"x3y8"3%"x43/e"x31/8"33/4"x4%"x3'/8"3%"x35/8"x31/e"

21.9527.9529.9521.95

POWER SUPPLY KITS (open frame with base plate, 3 hrs. assy, time)

ITEM USED FOR @+8Vdc @-8Vdc @ + 16Vdc @-16Vdc @+28Vdc

SIZEWxDxH UNIT PRICE

KIT1 15 CARDS SOURCE 15A

KIT 2 SYSTEM SOURCE 25A

KIT 3 DISC SYSTEM 15A

KIT 4 DISC SOURCE 8A

1A1A

2.5A3A2A

2.5A3A2A

4A5A

12"x6"x47/8"12"x6"x4%"14"x6"x4%"10"x6"x4%"

51.9558.9566.95

49.95

EACH KIT INCLUDES: TRANSFORMER, CAPACITORS, RESIS., BRIDGE RECTIFIERS, FUSE & HOLDER, TERMINAL BLOCK, BASEPLATE, MOUNTING PARTS AND INSTRUCTIONS.

DISC DRIVE POWER SUPPLY "R3" assy. & tested, open frame, size: 9" (W) x 5- (d> x 5- (H) 64.95

SPECS: +5V@5A REGULATED, -5V@ 1AREG., +24V@5A REG, SHORTS PROTECT.

IDEAL FOR 2 SHUGART 801/851 OR SIEMANS FDD 100-8/200-8 DISK DRIVES & ROCKWELL AIM-65.

SHIPPING FOR EACH TRANSFORMER: $4.75. FOR EACH POWER SUPPLY: $5.00 IN CALIF. $7.00 IN OTHER STATES. CALIF. RESIDENTS ADD 6% SALES TAX. OEM WELCOME.

MAIL ORDER:

P.O. BOX 4296

TORRANCE, CA 90510

SUNNY INTERNATIONAL

(TRANSFORMERS MANUFACTURER)Telephone: (213) 633-8327

STORE:

7245 E. ALONDRA BLVD.

PARAMOUNT, CA 90723

STORE HOURS: 9 AM-6 PM

302 BYTE May 1980

Circle 254 on inquiry card.

Now get OHIO SCIENTIFIC personal computerproducts with guaranteed, quick, mail order delivery.

ONLY S299

Ohio Scientific Superboard II

The first complete computer system on a board. Includeskeyboard, video interface and audio cassette interface.8K BASIC-in-ROM; 4K RAM. Requires power supply +5Vat 3 Amp.

"We heartily recommend Superboard IIfor the beginner who wants to get intomicrocomputers with a minimum cost. Areal computer with full expandability."

POPULAR ELECTRONICS, MARCH, 1979

"The Superboard II is an excellent choicefor the personal computer enthusiast on abudget."

BYTE, MAY, 1979

Ohio Scientific C1P Series.

The Challenger 1P. The best bargain inpersonal computer anywhere! 8K BASIC-in-ROM. 4K RAM. Cassette based with 53-keykeyboard. BS.W video interface, 30 rows x30 columns. Upper and lower case. 8K RAMS399.

Ohio Scientific C1P MF. Mini-floppy versionof the C1P. 8K BASIC-in-ROM. S995. SDKRAM and 0S-B5D software. Fullyexpandable. S1250.

SOFTWARE

Cassettes

Add Game

S 6.00

BASIC Tutor Series

S29.00

Torpedo

S 6.00

Address Book

S 8.00

Programmable

Calculator

S12.00

Savings Account

S 6.00

Breakout

S 6.00

Battleship

S 6.00

Bowling

S 6.00

Destroyer

S 6.00

Space War

S 6.00

Star Trek

S 6.00

Tiger Tank

S12.00

Disks

When ordering, specify

Challenger 1P, 4P

orBP

MDMS Education

System

S29.00

MDMS Checking andSavings Account

S29.00MDMS PersonalCalendar/AddressBook S29.00

Home Control II

S29.00DAC I MusicGeneration S39.00Baseball IS. II, Golf,Bowling, Hockey

S39.00Poker, Black Jack,Spades, Hearts, more

S29.00Tiger Tank, SpaceAttack, Etch-A-Sketch, more

S29.00Star Wars, Zulu 9,High Noon, more

S29.00Monster, Kite, ThreeLittle Pigs, HumptyDumpty and more[2 Disk Set] S29.00

Many, many more software systems areavailable to you. See our catalog forcomplete listings.

Accessories

AC-3P 12" BAA/ monitor, TV

AC-15P 12" Color monitor

AC-16P 2-8 Axis Joysticks with

cable

AC-11P Answer/Originate 300

baud modem with cable

AC-17P Home Security Starter

Set. 1 fire detector, 2 window

alarms. 1 door unit.

AC-18P 814" aluminized paper

printer. Upper/lowercase.

AC-9TP Centronics 799 110cps

tractor feed, business printer with

interface

AC-12P AC-Remote starter set.

Console. 2 lamp modules, 2

appliance modules, OS 65D home

control operating system

Disk Drives

CD 3P Single 5" mini floppy

CD 2P Dual 8" Disk with interface

and 0S-65D DOS

Power Supplies

PS 1. 5-volt @ 3 amps regulated.For use with Superboard II

Boards [Assembled and tested]CM 9P. 24K Static.610. 8K Static. Expandable to24K and dual mini-floppy controller.CA-14A. Votrax ■ voicesynthesizer.

CA-15 Universal Telephone Inter-face, rotary or touch toneCA-15V UTI with Votrax"'CM-6 48K Dynamic memoryboard.

4KP. 4K static RAM chip setCA12. 96 line parallel I/OBooks:

How to Program Microcomputers,By William BardenBasic and Personal ComputerBy Dwyer & CritchfieldHoward Sams C1P Service ManualHoward Sams C4P Service Manual

ss

125450

s

39

s

199

s

249

s

695

S 1250

S 175S 499S 1599

S 29

S 399

S 298

S 399

S 499S 799

S 499S 69S 175

S 8.95

S12.95S 7.95S15.95

Freight Policies

All orders of S100 or more are shippedfreight prepaid. Orders of less than $100please add S4.00 to cover shipping costs.Ohio Residents add 5.5% Sales Tax.

Guaranteed Shipment Cleveland

Consumer Computers S. Componentsguarantees shipment of computer systemswithin 48 hours upon receipt of your order.Our failure to ship within 48 hoursentitles you to $35 of software, FREE.

Ohio Scientific C4P Series.

The Challenger 4P. A 4-slot computer withone open slot. Highly sophisticated 1B colorvideo interface. 32 rows x 64 columns,upper and lower case. 8K BASIC-in-ROM, 8KRAM. 200-20KHz programmable tonegenerator. AC remote interface. Expandableto 32K RAM and two mini-floppy drives.S750.

The Challenger 4P MF. Mini-floppy versionof the 4P. Two to three times faster thancompetitors. More I/O built-in than any otherin its class. 24K RAM. Real time clock.Modem interface. Printer interface.Foreground/Background operation and much,much more. $1795.

Ohio Scientific 8P Series.

Challenger 8P. Ohio Scientific's mainframe-class. Personal computer. B slots with 6open. Cassette based with 8K BASIC-in-ROM. 8K static RAM, expandable to 32KRAM, and dual 8-inch floppy disk drive. S950.

Challenger 8P DF. A top of the line personaland small business computer. 32K RAM,expandable to 48K. Features dual 8" floppydisk drives. Audio output 200 20KHz. DACfor voice generation. Keypad interfaces.Joystick [2] interfaces. AC Remote. RealTime Clock. Printer S. Modem interfaces.And more. S2895.

To Order:

Or to get our free catalog

CALL 1-800-321-5805 TOLL FREE.

Charge your order to yourVISA or MASTER CHARGE ACCOUNTOhio Residents Call: [216] 464-8047.Or write, including your check or moneyorder, to the address listed below.

Hours:

Call Monday thru Friday8:OOAMto5:OOPME.S.T.

VISA'

^5

&

Bl( CLEVELAND CONSUMERI! COMPUTERS & COMPONENTS■ on Dmw /ICC97

P.O. Box 46627Cleveland, Ohio 44146

TO ORDER: CALL

1-800-321-5805

TOLL FREE

Circle 255 on inquiry card.

BYTE May 1980 303

Circle 256 on inquiry card.

Z80

$1250

APPLE GAME PORT REMOTE PLUG-INEXPANDER with SELECTOR!

Allows continuous connection of any three

of the Apple game port

options.

*3995

^599°

-base2.in

8038C

VCO Waveform Gen. -.,-,-w/sine $2oO

mm

4116

DynamicRAM

|MEMORV ADDON FOR THETRS-8(foR APPIE IP

lo 450ns

8lc,S4995

video fOO

12" BLACK & WHITELOW COST VIDEO #129MONITOR

00

1024X8 EPRM

2708

1024X8 E$745

450ns AMD. SGS

l1795

.LOGIC=3^« PROBET KIT

8216$

BUS DRIVER

199

SOROC

IQ120#74900

T.1./M.M.174LS24074LS24174LS243

B* si 74LS243

DustCavei74LS244

for Apple

keyboard *895disk $395

74LS374

$245

LIMIT 10 EACH

MH0026CJ1

RESISTOR NETWORKS

HHHB J270.4.7M15K,OHMS1.5K & 10K

DUAL CLOCK !DRIVER $ ,

IN STOCK

74S37374S374325

2716

^•^Jr 4sc

1GK EPROM

$27

^Pr^

95

450 ns single t5VTl. HIT.. INT.,SGS

■7TJPQKT

=595=

S-10016K ADDONBARE BOARD

2895

WITH DOCUMENTATION AND #•DETAILED INSTRUCTION BOOK

2114L

1024x4 Static RAM450 ns

'$475

I.C.MASTER

NEW

1980 '■"

ULN2001

High-current Drivers.Darlingtons 69C

I CONCORD

COMPUTER COMPONENTS

EPROM ERASER

DPT0 6EPR0MSIN 19 MINUTES6000 HOUR BULB LIFE -^

BV SPECTOLINE?4995

11971 SOUTH STATE COLLEGE

VISA-MASTER CHARGE

CHECK OR MO

ANAHEIM,CA. 92806

/-71 »\ no-r «M1 mmm ORDEFt-SlO.OO

(714)937-0637 amslsoforfrt.

We stock and selloverl2,000lynesofsemiconductors CAL.RES.ADO 6%

16KSTATICS

RAM

S-100 MEMORY ADD-ON

** FULLY STATIC OPERATION

** USES 2114 TYPE STATIC RANSMS

** +8 VDC INPUT AT LESS THAN 2 AMPS

** BANK SELECT AVAILABLE BY BANK PORT AND

BANK BYTE** PHANTOM LINE CAPABILITY■-" ADDRESSABLE IN 4K BLOCKS IN 4K

INCREMENTS** LED INDICATORS EOR BOARD/BANK** SOLDER MASK ON BOTH SIDES OF BOARD

ASSEMBLED $ OftQOO

& TESTED ^OyUU

California Computer Systems

(

Dual Trace OscilloscopeHITACHI 30 MHz

I TV sync-separater circuitft High-sensitivity 1 mV/div

(5MHz)■ Sweep-time magnifier

(10 times)

• Z-axis input (Intensitymodulation)

• Signal delay line

• X-Y operation

• Trace ■*.—.,■■» «,«Rotation $945.00

lore sensitive to your input

SD Systems

2700127002270032700427007270102701127012270132701427015270172701827024

SD

38001380023800338004300053800038007380103B01138013380163801738018380193802038021380223802338024380253802030028

ExpandaRAM Kit - Expaadaala RAM Qaara Kit (No BAMa)

VaraaHappi Flaiibla Diik Dtiva Conualltr Kit

SRC-100 Singli Baud Canpolat Kit

IIB Stanai Kit

EipanriaPROM Kit

Add-aaRAM(ISKDaviaaa)4IIE |Za0niaa)(paakaaa al aighl daviaaa

VOBS0Z4 Vidae Oiaplay Baatd Kl

EipaadeflAM II Fjpandabla RAM Baard Kit |IEK RAM)

KITS

0220

250

i.ulloa

Diik Dm

Cantiolit Raaid Kl. .

I Kit

295340175165370460350200250.250.320.230

Kit (Na RAMa).

ASSEMBLED

S 480

620

760

PROM-100 PROM

MPB-100 ZB0 BJMMI PioEaiiinp UnitAddon RAM (IEK daviaaa) 41 IB (Z00nSRC-ZD0 Singla Roetri Campulai Kit . .PioandnRAM II Eipandabla RAM Baud

Systems

EipindoHAM (16K nl on-bond RAM). .EipindoRAM (32K al on-boird RAM).EipindnRAM (4BX of un-boird RAM).

EipindoRAM (84K ol on-boird RAM) 900

V«rniilcjp|iy rio.il.lt Disk Drivi Conlrolltr 33S

SBC-10Q Singli Bomii Carnpulil ,. 350

ZIO Surttp Syitim 450

EipindiiPRQM 245

Cihlt tor 8" Diik Drift* B0

VDB-8024 Vidia Diipliy Bond 470

Ml* Git . 26 Prn Edgi DmHM (oos lad) 50

Cihlilar SD-IDD/S0-2aa InHrlici lo Tu.i IniuumtnliaiDPrinlir... 80

Cibti. smui ii obovi (Inliiiiil) 1 20

Cibi.

. IExiii

(I).

ExpanrfoRAM II (16K Population] 610

EipindoRAM II (32K Population) 840

EipindoRAM II |4ilK Population) 1 070

EipindoRAM II |64K Popul.lion) 1 300

Vim floppy II Do libit Dimity Flnibla Diik Onvt Conliollti 430

PRDU-tOO PRDM Pramunmir 265

MPB-100 ZBO Miciopmonor Cu.nl 325

MMM Sinala Bmrd Computir 400

NEW

H1CKOK

LX304

DIGITALMULTIMETER

Compact

Accurate

Dependable

95

89

FunctionGenerator

KIT

XR-2206KB

19

95

LEDS

.200 in. dla.

XC556R red 5for$l

XC556G green 4 [or $1

XC556Y yellow....4 for $1

.125 in. dla.

ED209R red 5lor$l

ED209G green ....4 for $1ED209Y yellow....4 for $1

Light Emitting Diode

P1"\QET Red-Orange

Color mixingpossible dueto separate an-ode terminals.

and Green

ONLY

$-| 60

Flasher LED

ONLY

FRL-4403

Red LED and

FlasherICChip Q2v

in One Package

Universal Oscilloscope

Probe

£— $36

OO

SWITCHABLE X1 and X10 ATTENUATION FACTOR

KEY ADDITIONAL FEATURES: • 100 MHz bandwidth • Heavy dutytip • Break resistant center conductor • Slender, flexible cable

• 6 ft. length • Wide compensation range • Fits all scopes

• Ground reference can be activated at tip • Includes SPRUNGHOOK, I.C. TIP. BNC ADAPTOR, INSULATING TIP and TRIMMERTOOL accessories

8080A

MICRO- $C95PROCESSOR 3

EPROM

529

(5 Volt)

2716

90

Vacuum Vise

Vacuum baled light duly wipefor precision handling of smallcomponents and assemlRugged ADS constructorin. wide jaws. 1 % in. travel formaximum versatility- Aliofeatures sciaw lugs for panunt installation. A -» -

vv-i $3.49

* 15% *

DISCOUNTCOUPON

Bring this COUPON into one of our stores ormail to our Mail Order address shown below and

receive a 15% l»IS( (MMon purchases from this Ad of $1 00.00 or more.

Otter EXPIRES on May 31,1 08©

Send check or Money Order to: P.O. Bon 220BY. Culver Ciiy CA 00Z3Q.

California residents add 6% sales tax. Minimum Order: $10.00.Add $1.00 to cover postage and handling. Master Charge and Visa welcomed.Please include your charge card number,Interbank number and expiration date. PHONE ORDERS: (213) 641-4064

MAIL ORDER

PORTLAND

SANTA ANA

CULVER CITY

P.O. Box 2208R

1125 N.E. 82nd Ave

1300 E. Edmger Ave.

IIOBO Jeflcrson Blvd.

Oliver City.CA 90230

Portland, OR 97220

Santa Ana. CA 92705

Culver City. CA 90230

(213) B41-40B4

(5u3| 254-5641

{714) 547-8424

(213) 390-3695

TUCSON

HOUSTON

ATLANTA

SUNNYVALE

4518 E. Broadway

2649 Richmond

3330 Piedmont Rd, N.E.

1054 E. ElCammo Roa

Tucson, AZ 85711

Houston. TX 77098

Atlanla. GA 30305

Sunnyvale. CA 94087

(B02) BBI-Z34B

(713) 529-3489

(404) 2BI-7I00

(408) 243-4121

304 BYTE May 1980

Circle 257 on inquiry card.

Radio Hut Radio Hut Radio Hut Radio Hut

USsS Radio Hut

201 L0CHW00D MALL • DALLAS, TEXAS 75218

ORDER BY PHONE—214-324-5509

PLEASE WRITE FOR CATALOG

PRICES SUBJECT TO CHANGE

WITHOUT NOTICE

ORDERING INFORMATION & TERMS: Orders under $15.00add 75c handling. No COD. We accept Visa. MasterCharge.and American Express cards. Tex. Res. add 5% tax. Foreignorders (except Canada) add 20% P&H. 90 Day Money BackGuarantee on all items. Add 5% P&H. maximum $5.00.ORDER BY PHONE — (214) 324-5509

IThe EXPANDORAM is available in versionsIfrom 16K up to 64K, so for a minimum invest-Iment you can have a memory system that willIgrow with your needs. This is a dynamic mem-lory with the invisible on-board refresh, and ITWORKS!I • Bank Selectable

Phantom| • Power 8VDC, +16VDC, 5 Watts

Lowest Cost Per Bit

Uses Major Brand 16K RAMS| • PC Board is doubled solder masked and has

silk-screened parts layout

Extensive documentation clearly written

SD EXPANDORAM

• Complete kit includes all Sockets for 64K

• Memory access time: 375ns, Cycle time:500ns.

• No wait states required

• 16K boundaries and Protection, via Dip ISwitches

• Designed to work with Z-80, 8080, 80851CPlfs

EXPANDORAM 64K Kit (16K Ram)

16K $239.95

32K 309.95

48K 379.95

64K 449.95

SD'S PROM 100 PROM Programmer Board

I The PROM-100 Programmer is a development tool forI S-100 Bus computer systems. The Zero InsertionI Force Programming Socket extends above the card[cage height for easy access to PROM devices. Soft-Iware verifies PROM erasure, verifies program loadingland provides for reading of object file from Disk orI PROM and programming into PROM/EPROM. Fea-tures include: On-board generated 25vdc Program-Iming pulse, TTL compatible, maximum programmingttime lor 16,389 bits is 100 seconds. Programs: 2708,lintel 2758, 2716, 2732 and Tl 2516. DIP SelectableI EPROM type.I PROM-100 Board Kit $149.95

SD'S SBC-200SINGLE BOARD COMPUTER Kit $289.95

S-100 Bus compatible and based on the powerful Z80 microprocessor, the SBC-200 meets the needs of a Z-80 CPU boardwith many additional features. Ideal for Industrial and controlapplications. All of the same features that have made theSBC-100 famous, PLUS 4MHz OPERATION. • S-100 BusCompatible • Z80 Central Processing Unit • 1024 Bytes otRandom Access Memory • 8K Bytes of PROM using 2716 •Serial Input/Output Port (with Asynchronous and SynchronousOperation) • Parallel Input and Output Pods • Four ChannelCounter/Timer (Z80-CTC) • Software Programmable BaudRate Generator • No-Front Panel Required lor Operation • 4MHz Operation.

SD'S VERSAFLOPPY II

• IBM 3740 Compatible Soft Sectored Format for Single Den-sity Drives • Operates with Single and Dual Sided Drives.Single or Double Density Drives and 5" & 8" Drives — in anycombination ol four simultaneously • Drive Select and SideSelect Circuitry • S-100 Bus Compatible • Vectored InterruptOperation Optional • Phase Locked Loop Data Recovery Cir-cuit • Operates with Z80 CPU's • Uses FD1791-1 ControllerChip • Ther Versafloppy II incorporates all the possible fea-tures of a flexible disk drive controller into one board. Capableof handling four drives simultaneously, combinations of an/variety are possible, such as 5." single sided, 8' dual density |dual sided, 5" dual density single sided. Most popular drivesare controlled directly with the Versafloppy II. The operatingsystem for the Versafloppy II is the extremely powerful SDOSavailable for SD Systems. Diagnostic and control softwareavailable to complete your disk system. KITS335.95

SD'S VDB-8024VIDEO DISPLAYBOARD

The VDB-8024 featuresits own on-board Z80I microprocessor. This gives the capability of using soft-ware (included in ROM) to control functions and en-hancements without interference with the computer'sCPU. Included in the special features: 80 charactersI by 24 lines display, keyboard power and interface,I composite and separate video output, 2K on-board[RAM, a total of 256 available characters, full cursorI control, forward and reverse scrolling, underlining,I field reverse, field protect enhancements, program-| triable characters. kit $329.95 a&t $389.95

SD'S

"VERSAFLOPPY I"

KIT

FEATURES: IBM 3740 soft sectoredcompatible, S-100 BNS Compatible for 2-80or 8080. Controls up to 4 drives (single ordouble sided). Directly controls the followingdrives: Sugart SA400/450 Mini Floppy • Shu-gart SA800/850 Standard Floppy • PERSCI70 and 277 • MFE 700/750 • CDC 9404/9406

$189.95

SD'S SBC-100SINGLE BOARDCOMPUTER

The SBC-100 provides a |complete micro-computeron a single board! The Z80 microprocessor is used as the heanof the SBC-100. The SBC-100 meets all the requirements of aZ80 CPU board with the added features of I/O pons, counter/'timer channels, on board RAM. provisions for PROM/ROMand a software programmable baud rate generator. S-100 Buscompatible, the SBC-100 features are: 8K bytes of availablePROM, 1024 bytes on-board RAM. Serial I/O with both syn-chronous and asynchronous operation. Parallel I/O pons.Operational Vectored Interrupts, and Four Counter/TimerChannels. SD Monitor available for RS-232 and Video Ter-minals. Disk based system software also available.SBC-100 KIT $249.95

TARBELL FLOPPY DISK INTERFACE

I Compatible with Z80 & 8080. S-100 Bus. UsesCPM operating system. Plugs directly into yourIMSAI or ALTAIR • Fastest transfer rateKIT $190.00 Assembled & Tested $260.00

TARBELL CASSETTE INTERFACE

I Plugs directly into your IMSAI or ALTAIR •Fastest transfer rate • Extremely reliable •Phase encoded • 4 extra status & control lines KIT $99.95

CB2 Z-80 CPUBoard Kit $186.00

Operates at 2 MHZ or 4 MHZby DIP switch selection andincludes two sockets for 2716or 2732 EPROMs or TMS4016 2K RAMs. Jumperoptions generate the newIEEE S-100 signals.

-SS37

VB3 80 Character

Video Board Kit

$299.95

• 80 char, per line, up to 51lines • Graphics up to 160 *204 matrix • Up to 256 userdefined symbols (optionalEPROM) • Composite video

Z80 STARTER KITKit: $279.95 Assembled & Tested $349.95

I SD System's Z80 Starter Kit enables the novice to build acomplete microcomputer on a single board Featuring the

I powerful Z80 microproces-sor, the Z80 Starter Kit fea-tures • Keyboard and Dis-play • Audio Interface •PROM Programmer • Ex-pansion and Wire WrapArea • On Board RAM • 4Channel Counter/Timer •Z-BUG Monitor in PROM •I/O Ports.

.'■■

If g»J *§* ■- \ i - '«&■:,

§■! aiMtilMU

•■

lif-'- ■■■'■■, |l

. ■. ■ •inn

IPEitel

IBBIBB

" O "*#'.. B

IBB:

NOVATION CATACOUSTIC

COUPLER/MODEM$189.00

Let your computer communi-cate with other computers. BellSystems 103 compatible 300baud, answer or originate

PB1 2708/2716 Programmer & 4K/8K

EPROMBoard Kit J^/j? $124.00 I

• S-100 bus • 2 separate programming sockets for 2708 or2716 (5V) EPROMs • Programming voltage generated onboard — no need for an external power supply • Softwarecontrol of 2708/2716 programming selection • LED indicatorfor programming mode and an on-off switch for programmingvoltage • 4 sockets for 4K of 2708 or 8K of 2716 EPROMs •Unused EPROM sockets do not enable data bus drive so ihe |board is never committed to the full 4K or 8K of memory •Jumper selectable wait states (0-4) for fast or slow EPROMS

SYM-1

Reg. $269.00NOW $219.00

• KIM-1 Compatible• 4K ROM Monitor

' 1K Bytes 2114 RAM

• 65K Memory

Expansion

• User EPROM 2716

104 2 Parallel/2 Serial I/O Board Kit $126.00

• S-100 bus • 2 serial I/O ports (2 in & 2 out) • Independent |baud-rate selection from 55 to 9600 baud • Regulated - 5V.■+ 12V & -12V outputs provided on both serial headers • 2 Ilatched parallel I/O ports (2 in & 2 out) • Independent DIPswitches for setting address • Interrupt capability provided foron serial and parallel I/O ports • + 8V <w 0.95A. + 16V @ 0.6A.&- 16V @ 80mA typical ——j/J

VB1B VIDEO BOARD KIT $124,001

• S-100 bus • 64 or 32 characters per line (DIP switch select-able). 16 lines • Graphics 128x48 matrix • Uppercase, lowercase. Greek characters, symbols and numbers • 7>9 dotcharacter matrix • Black-on-white or white-on-black • Timing ,60Hz vertical rate. 16.2KHz horizontal rate. Crystal 12.44MHz |

• Parallel and composite video output (US TV signals), sep-arate video, horizontal and vertical sync ssfft

S-100 Bus CompatibleUp to 4Mhz OperationExpandable Memory from 16K to 256KDIP Switch Selectable BoundariesUses 16K (4116) or 64K (4164) MemoryDevices

Page Mode Operation Allows up to 8 MemoryBoards on Busi Operates with Z80 CPU'sPhantom Output DisableInvisible Refresh (Synchronized with WaitStates)

SD'S EXPANDORAM IIThe Randem Access Memory

SD Systems' ExpandoRAM II is a dynamic RAMIboard with capacities from 16K bytes (4116) tol256K bytes (4164). It operates on the industry|S-100 Bus. The design allows 8 boards to op-ierate from the same S-100 Bus. The Expando-IRAM II is compatible with most S-100 CPU's|based on the 280 microprocessor.EXPANDORAM II KIT

16K $295.95

32K 369.95

48K 444.95

64K 519.95

{Q Circle 258 on inquiry card.

£ Radio Hut Radio Hut

Radio Hut Radio Hut SS

JADE. INFLATIFOR THE 80's.

OPENING BOUT

I:

J3

EXPANDORAM

Expandable to 64K Using 4116 RAMS

Interfaces with most popular S-100 boards

Bank selectable; PHANTOM provision

Draws only 5 watts fully populated

Designed to work with Z-80, 8080, and 8085 systems

No wait states required

I6K boundaries & protect via dip switches

Kits come with sockets for full 64K

Invisible refresh

MEM-64I33K 64 K KIT $.199.95

MEM-64133A A&T $449.95

MEM-48132K 48K KIT $334.95

MEM-48132A A&T $384.95

MEM-32131K 32K KIT $269.95

MEM-3213IA 32K A&T $319.95

MEM-16130K 16K KIT $204.95

MEM-I6I30A 16K A&T $259.95

Sale Price $475.00

32K STATIC RAM

Expandable 8K/32K, 2/4MHz, KIT/A&TSwitchable 2 or 4 MHz

THE JADE BIG Z

Z-80A CPU with Serial I/O Port

This CPU can accomodate a 2708, 2716. or 2732EPROM in SHADOW mode, allowing you to use a full64K of RAM. The MWRITE signal is generatedautomatically if you use the board without a front panel.There's also an independent on-board US ART to controlthe RS232 serial port at baud rates from 75 to 19.200.

We've sold thousands of these high quality S-100CPU boards at SI 59.95; but now, in a brief fit of financialinsanity, we're offering them to you for only $135.00!Don't pass this one up!

C PU-30201K (KIT) $135.00

CPU-3020IA (A&T) $199.00

CPU-30200B (BARE BOARD) $35.00

5 D Systems

EXPANDORAM II

4 MHz RAM Board Expandable to 256K

S-100 bus compatible, up to 4 MHz operation

Expandable memory from I6K to 256K

Dip switch selectable boundaries

Page-mode allows up to 8 boards on the same bus

Invisible refresh; PHANTOM output disable

Designed to operate in Z-80 based systems

MEM-64633K 64K KIT $509.95

MEM-64633A 64K A&T $559.95

MEM-48632K 48K KIT $439.95

MEM-48632A 48K A&T $489.95

MF.M-32630K 32K KIT $359.95

MEM-32630A 32K A&T $409.95

MEM-16630K I6K KIT $279.95

MEM-16630A 16K A&T $329.95

Solid State Music

PB-1

EPROM Programmer for 2708 or 2716

MEM-99510K (KIT) $125.00

MEM-99510A (A&T) $175.00

JADE DOUBLE-D

Double Density Disk Controller

Read/write single or double density, 8" or 5'/i" drives

On board Z-80 insures reliable operation

CP/M compatible in either single or double density

Density is software selectable

Up to 4 single or double sided, single or double density

drives may be mixed on the same system

EIA level serial printer interface on board-up to 9600

baud (perfect for despooling operations)

All the hard work of disk access is done by the on board

Z-80A and 2K memory, leaving your host CPU free

for its normal duties

Uses IBM standard formats for proven reliability

THIS BOARD REALLY WORKS!!!!!!

IOD-1200K {DOUBLE-D KIT) $285.00

IOD-1200A (DOUBLE-D A&T) $349.00

1OD-1200D (MANUAL ONLY) $15.00

Terminal SaleADDS REGENT

Our Finest Line of Terminals

REGENT 20 $795.00

24 lines X 80 characters, EIA and 20ma currentloop interfaces, 110 to 9600 baud, 96 ASCII codes plus32 control codes, both upper and lower case, 8X8dot matrix, reverse video, auxiliary EIA serial interface,and addressable cursor.

REGENT 25 $850.00

All the features of the Regent 20 plus an 18 keynumeric and cursor control pad.

REGENT 40 $1195.00

All the features of the Regent 20 plus a 14 keynumeric pad, 8 function keys, 5 cursor control keys,auxiliary port control key, reverse video, underline,blinking, plus full, half, and zero intensities, 8X8 dotmatrix, II special line drawingsymbols, reverse scrolling,and send/receive capability using the Regent 40's bi-directional interface.

REGENT 60 $1495.00

All the features of the Regent 40 plus Print Local,Editing, and Transmission Mode keys, business graphics,bar charts, histograms, and graphics, ability to insertor delete characters or lines, buffered mode reducessoftware needs, and can transmit data at baud ratesother than rate received.

Special Package Price

RS-232 SET-S6.50

1 Male DB-25, 1 Female DB-25, 1 Cover

JADE DISKETTES

>l;i<>iihi<<-iii Magnetic M«*tlia™

51/]" single sided, single density, box of 10

MMD-5110103 (SOFT SECTOR) S29.95

MMD-5I11003 (10 SECTOR) $29.95

MMD-5111603(I6 SECTOR) $29.95

5'xi" double sided, double density, box of 10

MMD-5220103 (SOFT SECTOR) $39.95

8" single sided, single density, box of 10

MMD-8110103 (SOFT SECTOR) $34.95

8" single sided, double density, box of 10

MMD-8120103 (SOFT SECTOR) $55.95

8" double sided, double density, box of 10MMD-8220103 (SOFT SECTOR) $57.95

S D Systems

VERSAFLOPPY

Versatile Floppy Disk Controller

IBM 3740 soft sectored format

S-100 Z-80 or 8080 compatible

Controls up to 4 single or double sided drives

Compatible with all popular disk drives

CP/M compatible

Listings for control software included

1OD-1150K (KIT) $239.00

IOD-1150A (A&T) $289.00

5 D SystemsZ-80 STARTER

Complete Z-80 Microcomputer

On-board keyboard, display, EPROM programmer,cassette interface and S-100 interfaceWire-wrap area and room for 2 S-100 connectorsTwo 8-bit parallel I/O ports, 4 channel CTC,5 programmable breakpointsExamine & change memory. I/O ports, or register

CPS-30010K (KIT) $239.95

CPS-30010A (A&T) $299.95

TITLE MATCH

S D Systems

SBC-100/200

2 or 4 MHz Single Board Computer

S-I00 bus compatible Z-80 CPU

IK of on-board RAM

4 EPROM sockets accomodate 2708. 27I6, or 2732

One parallel and one serial I/O port

4-channcl counter timer chip (Z-80 CTC)

Software programmable serial baud rates

CPC-30100K (2 MHz KIT) $239.95

CPC-30100A (2 MHz. A&T) $289.95

CPC-30200K (4 MHz KIT) $259.95

CPC-30200A (4 MHz. A&T) $309.95

Coming SoonNEW JADE P/S I/O

Parallel Serial Interrupt Board

Z-80 SIO, PIO, 2 CTCs, expands to 2 SlOs, 4 CTCs4 serial ports (async, sync, bisync, SDLC/HDLC)2 parallel ports with full handshakeSoftware baud rate generators, interval timers, counters,and generates 32 vectored interruptsDesigned especially for MP/M multi-user multi-tasking operating systems. For use with Z-80 only

1OI-1045B (BARE BOARD) $55.00

IO1-I045K (KIT) $169.95

IO1-1045A (A&T) $224.95

Solid State Music

1/0-4

2 Serial & 2 Parallel I/O Ports

IOI-1010K (KIT) $149.95

IOI-1010A (A&T) $199.95

ON FIGHTEROUND #2.

S D SystemsVERSAFLOPPY II

Double Density Disk Controller

Single or double density floppy disk controller

985600 bytes on 8" double sided diskettes

259840 bytes on double sided $%* diskettes

S-I00 bus (IEEE) standard compatible

IBM 3740 format in single density

8" and 5lA" drives controlled simultaneously

Operates with Z-80, 8080, and 8085 CPU's

Controls up to 4 drives

Vectored interrupt operation optional

100-1160K KIT $299.95

100-1160A A&T $349.95

TKO CHAMPS

ATARI 800

Don't Miss Out on Our Special Sale Price

At last there is a machine designed to give seriouscompetition to Apple and Radio Shack. This computercontains many advanced technical features such as:built in RF modulator for use with a standard TV;8K of internal RAM (expandable to 48K), 8K BASIClanguage included; extremely sharp high-resolutioncolor graphics; and built-in peripheral I/O ports.Software is available in plug-in paks and cassettetapes, with many programs available in the areas ofentertainment, education, and business/homemanagement.

Available accessories include a printer, disk drives,game controller paddles, and memory expansioncartridges.

And JADE has the Atari 800 in stock at a specialintroductory price.

ATARI 800 $825.00

810 DISK DRIVE $575.00

820 PRINTER $550.00

I6K RAM EXPANSION KIT $169.95

CX30-04 PADDLE CONTROLLER $19.95

CX40-04 JOYSTICK CONTROLLER $19.95

ATARI 400 $599.95

We Think It's Superior

SDOS

A New Disk Operating System

SDOS is a disk operating system which will run anyprogram that runs under CP/M*. It is designedspecifically for use with the SBC-100/Versafloppy (1 orII) hoard set by S.D. Systems. SDOS actually has morefunctions than CP/M. including file attributes, disk label,and read/write logical blocks. It provides additionalprotection features and is expandable to a multi-userrealtime system. And if all that doesn't impress you.SDOS also contains S.D.'s ASSEMBLER/EDITOR/LINKER package and CBAS1C 21

SFX-55001002M (5"4" W/MAN) S150.00

SFX-5500I006F (8" W/MAN) $150.00

SFX-55001000D (MANUAL ONLY) $ 15.00

*CP/ M is a trademark of Digital Research

L

TextoolZIP* DIP II SOCKETS

Is

11 111 11

3

6 PIN ZIP* DIP II $5.50

24 PIN ZIP* DIP II $7.50

40 PIN ZIP* DIP II 10.25

* ZERO INSERTION PRESSURE

Circle 297 on inquiry card.

COST FIGHTERS

RAMS

211.02(2 MHz) $1.25

211.02(4 MHz) S1.50

21141.(2 MHz) S5.75

21141.(4 MHz) S5.95

4116 (250ns) $8.95

4116 (200ns) $9.50

4127 (70ns) $39.95

4164 (64K x 1) $175.00

5257 (2 MHz) $6.75

5257 (4 MHz) $7.25

BAUD RATE GENERATORS

MCI441I $10.00

CRYSTAL $4.95

SUPPORT DEVICES

8212 $2.50

8214 $4.65

8216 $2.95

8224 $3.25

8226 $3.85

8228 $4.95

8238 $4.95

8243 $8.00

8250 $14.95

8251 $6.50

8253 $13.95

8255 $6.50

8257 $19.95

8259 $17.95

8275 $49.95

8279 $8.95

3881 $12.95

3882 $12.95

3883 $45.00

6800 SUPPORT

6821P $5.95

6828P $11.95

6834P $12.95

6840P $18.75

6850P $4.80

6852P $5.79

68751 $7.40

68488P $25.00

PROMS

2708 (450ns) $8.95

2716 (450ns) $34.95

2716 (Sv) $34.95

2732 (5v) $95.00

2758 <5v) $34.95

MICROPROCESSORS

7.-80 $10.95

7.-80A $12.50

6502 $11.50

6800 $11.95

6802 $17.95

6809 $39.95

8035 $24.00

8035-8 $24.00

8080A $6.59

8085 $15.95

TMS9900.II $39.95

HARTS

AY5-I0I3A $5.25

AY3-1014A $8.25

TRI602B $5.25

TMS60I1 $5.95

IM6403 $9.00

Special Package PriceROCKWELL AIM-65

The Head-Start in Microcomputers

KIM-I compatibleOn-board printerFull ACS1I keyboardAIM-65 w/lK RAM. .$395.00AIM-65 w/4K RAM. .$439.958K BASIC ROM..$100.00POWER SUPPLY..$59.95 /«CASE for AIM-65. .$49.95 <-4K Assembler/Editor. $85.00

Special Package Price $599.00

4K AIM-65. 8K BASIC ROM, Power Supply, and Case.

JADE

Memory Expansion KitsFOR

TRS-80 APPLE EXIDY

Everything you need to add I6K of memory toyour computer. Your kit comes neatly packaged witheasy to follow instructions. In just minutes your computeris ready to tackle more advanced software.

$59.95

Integral Data Systems

THE PAPER TIGER

132 Column Dot Matrix Printer

Up to 198 CPS

1.75 to 9.5 inch adjustable

tractor.

Parallel and serial

interface.

98 character ASCII set.

80 to 132 columns.

6 or 8 lines per inch.

Eight software selectable

character sizes.

110,300,600. or 1200 baud.

PRM-33440 $950.00

PRM-33441 (GRAPHICS & 2K BUFFER) . $1050.00

/'

SPECIAL

?/ \

SALE

1

L

PRICE

, '

Digital Research has done it again! This new releaseof their industry standard disk operating system isbound to be an even bigger hit than the original version.All of the fundamental file-size restrictions of releaseI have been eliminated, while maintaining full com-patability with the earlier versions. This new releasecan be field-configured by the user for a single mini-diskup through a multiple drive hard-disk system with 128megabyte capacity. Field configuration can be ac-complished easily through use of the Macro Library(DISKDEF) provided with CP/M 2.0.A powerful operating system for only $150.00

Jade's New Motherboards

THE ISO-BUS

6-SLOT

BARE BOARD

$24.95

KIT

$49.95

ASSEMBLED & TESTED

$59.95

12-SLOT

BARE BOARD

$39.95

KIT

$89.95

ASSEMBLED & TESTED

$99.95

18-SLOT

BARE BOARD

$59.95

KIT

$129.95

ASSEMBLED & TESTED

$149.95

Special Price for

NOVATION CAT

Acoustic Coupler/Modem

$157.50

Let your computertalk to other computersBell Systems I03 compatible300 baud, answer or orginateIOM-5200A (SALE PRICED)

$157.50

PLACE ORDERSTOLL FREE

Inside California Continental U.S.

800-262-1710 800-421-5500Write for our FREE 1980 catalog

For customer service or technical inquiries call

213-973-7707TERMS OF SALE: Cash, checks, money orders

and credit cards accepted. Minimum order SI0.00.California residents add 6% sales lax. Minimumshipping and handling charge $2.50. Prices are forU.S. and Canadian delivery only and are subjectto change without notice. For export prices andinformation send for a JADE INTERNATIONA!.CATALOG.

COMPUTER PRODUCTS

490I W. Rosecrans. Hawthorne. CA 90250

EVERY MONTH

BUY, SELL OR TRADE ALL TYPES OFCOMPUTER EQUIPMENT AND SOFT-WARE (pre-owned and new) among20,000 readers nationwide in BIG(11x14") pages. Classified ads areonly 10' per word and are indexed foreasy and last location. Subscription:$10 a year/12 issues. Bank cards ac-cepted. Money back guarantee.

CnmPUTSR SHOPPSR

P.O. Box F-14

Titusville, FL 32780

(305) 269-3211

1U1M] IlflflT

16K UPGRADE KIT FOR TRS-80, APPIE, PET,

SORCERER $70

Mostek 4215-3 200ns 16K x 1 RAMS

MICROPOLIS 8" HARD DISK DRIVE with

Power. S-100 controller

9 Megabyte $3995

27 Megabyte $4495

45 Megabyte $4995

Tl 994 $1050.00

DISCOUNTS on EXIDY SORCERER, PET, mostother systems, peripherals, and software.

MICROCOMPUTERS,PERIPHERALS AND SOFTWARE

1015 NAVARRO SAN ANTONIO. TEXAS 78205

512/2?? 1427

MEMOREX

Floppy Discs

Lowest prices. WE WILL NOTBE UNDERSOLD!! Buy any

quantity 1-1000. Visa Masterchargeaccepted. Call free (800)235-4137for prices and information. Allorders sent postage paid.

PACIFICEXCHANGES

100 Foothill Blvd.San Luis Obispo. CA93401. (In Catcall

(805) 543-1037)

Circle 260 on inquiry card.

Circle 261 on inquiry card.

Circle 262 on inquiry card.

DISBURSEMENTS & CASH RECEIPTS JOURNALS

In stock & ready to go to work, ready to

ship....no waiting

a.) Co-authored, debugged and used by alicensed, practicing CPA.

b.) A copyrighted document balance routineprovides for no-fault entries.

c.) As many as 4 Gen. Ledger postings foreach document, can all be different.

d.) Document types supported by programs:DJ-1001 Cash/Checks/PayrollCJ-2001 Deposifs/R.O.A/Credit Memo

e.) Complete audit trails for analysis.

f.) Concise, ready-to-use printouts.

g.} No special training. Programs use live-cueing at every step.

h.) Fully Documented, with listings, &supplied on 5%" diskette, written inTRS-80 Basic.

i.) Also available in MOD II format.

j.) Total support-for 1-year from date-of-purchase.

DISBURSEMENTS JOURNAL DJ-1001 $95.00

CASH RECEIPTS JOURNAL CJ-2001 $75.00SPECIAL..BOTH PROGRAMS ONLY $145.00

Complete software packages, and computer

supplies at competitive prices.

Checks O.K. S & A DATA SYSTEMS

Master Charge/Visa POBOX39

NO COD's Craig, CO 81625

TOLLFREE

NO CHARGE 1-800-854-2003 (exl 804)In Calif. 1-800-522-1500 (ext 804)

TRS-80 users

Learn FORTH

FORTH is a structured high level language thaidramatically cuts program development time. Youcan expand the HQRTH language by defining new

operations and data types. FORTH programs arecompiled to reduce memory space and speed execu-tion.

linyFORTH is a complete version ol the powerfulFORTH language tailored io the TRS-80. ThelinyFORTH system includes FORTH, a text editor,an assembler, graphics, and casselte I/O.

Learn FORTH on your own computer. ThelinyFORTH user's manual contains hundreds ufexamples to teach you FORTH in a hands-on style.linyFORTH lor 16k level II TRS-80:

Cassette and full documentation $29.95

Documentation onh $ l).95

All orders are full} jlui run teed. And 51.51) forpostage and handling. Order with check, moneyorder. Visa, or Mastercharge.

Write lor a FREE booklet describing FOR If I.

The Software Farm

Box 2304 Dept. A-21 Reston, VA 22090

DES-MARELECTRONICS

2306 Remo Court

Santa Clara, CA. 95054

(408) 496-0692

BRAND NEW (PLUG IN & RUN)TRS-80' 16K LEVEL 2$699.00 DELIVERED

TRS-80 TOTAL COMPATIBLE

DISK DRIVES WITH CABLE

(JUST PLUG IN & RUN)

$399.00 DELIVERED

•CHECKS OR MONEY ORDERS•PRESENT LEAD TIME: 2 WEEKS*CA. RESIDENTS 6.5% TAX

'T.M. OF TANDY CORP.

Circle 263 on inquiry card.

Circle 264 on inquiry card.

Circle 265 on inquiry card.

S-100 A/D

• S-100 Bus Compatible A/DConverter

• 12 Bit Accuracy

• 16 Channel Analog Input

• Programmable Gain Amplifierwith Sample-and-Hold

• High Quality Commercial/Industrial Construction

2 and 4 Channel, 12 Bit D/ABoards also available.

CALIFORNIA DATACORPORATION

34 75 Old Cone jo Road, Suite C10Newbury Park, California 91320(805)498-3651

Power Supplies @f|°'*»ps

output" rt'Vislm» SURPLUS UNITS IN

regulation oi- ™BmV LIKENEWCONDITION

NL-FL. ■ 0 1". - SmVtorlD'.

'LE JmVBMSm.il JO mV

STABILITY Typically 10m

REMOTE SENSING. REMOTE VOLTAGE ADJUSTMENTOVERLOAD PBOTECTION and OVERVOLTAGE PROTECTION«LSO AVAILABLE IN 1Z VDC IJ AMPS ST9 00per unil

79.°°per unit

ouse marked 22/44 EDGEBOARD CONNECTOR

Darlington TRANSISTOR T|N SOLDEBTAIL .156" x .200"

LARGE QUANTITIES AVAILABLES1.35each 10forSl2.50

REED RELAYS

ALL CLECTROniCS CORP.

905 S. Vermont Ave > Los Angeles. Calif. 90006DEPT. BY-1 (213)3808000 TERMS

STORE & WAREHOUSE HOURS IwrUMnsiruo

Mon. - Fri. Saturday -Addsijo

9AM-5PM

10AM-3PM

SEND FOR OUR FREE CATALOG .nctdOWiw

DISCOUNT PRICES

NORTH STAR

APPLE II

MICROTEK

ANADEX

TRENDCOM

CENTRONICS

SOROC

INTERTUBE

THINKER TOYS

SOLID STATE MUSIC

& OTHERS

Call for Prices

(301)694-8884

FREDERICK COMPUTER

PRODUCTS

Municipal AirportFrederick, MD. 21701

Circle 266 on Inquiry card.

Circle 267 on inquiry card.

Circle 268 on inquiry card.

Circle 270 on inquiry card.

UP TO 25% OFF

IMMEDIATE DELIVERY: Why wait 5 months for hardware fromother suppliers—get it quicker—and at lower prices NOW.

TRS 80 MODEL II

• 64 K RAM • Vi MEG DISKFIRST EXPANSION DRIVESECOND OR THIRD DRIVELINE PRINTER III Reg. $1999.00

$3899.00

899.00

600.00

NOW $1859.00

TRS 80 MODEL I

LIST OURPRICE PRICE

4 K LEVEL I SYSTEM S499 00S464 10

4 K LEVEL II SYSTEM S61900 $57570

16 K LEVEL II SYSTEM S849 00S789 60

EXPANSION INTERFACE 10 K Momory) $299 00 $278 10TELEPHONE MODEM $199.00 S185.10

LIST OURPRICE PRICECENTRONICS 730 S995 00 $695 00

CENTRONICS 737

• 100 CPS

• LETTER QUALITY DOT MATRIX S95000

• TRUE DESCENDERS

NEC SPINWRITER 5530 (wjili Traclors) 3195 00 2950 00

YOUR OWN TRS-80 SYSTEM AT TREMENDOUS SAVINGS

MAY SPECIAL

Good Until May 31, 1980

MINI DISK DRIVES NOW $350

Over $135 less than Radio Shack's!

WE ARE COMMITTED TOTHE TRS-80 and THETRS-80 USERSFully compatible with RadioShack's operating systemTRSDOS™ and drives. Justplug in and runl

• One, two, three or fourdrive configurations, 102k to408k bytes.

• All systems include a patchprogram to upgradeyourTRSDOSto 40 tracks.

• Cases are furnished in gray to match your system.IMMEDIATE DELIVERY: Why wait 5 months

for mini disk drives from other suppliers—getbetter drives-quicker-and at lower prices now!ORDER NOW TOLL FREE 800-345-8102

IORDER NOW TOLL FREE 1 - (800) - 345-8102

NEW!

FOR MODEL II

10—MEG FIXED/REMOVEABLE HARD DISK DRIVE WITHSOFTWARE AND CONTROLLER ONLY $6495.00

NEW! THE SOURCE

A new information and commu-nication network to add powerand utility to your micro.Call or Write for details.

BUSINESS SOFTWARE

Model I

Model II

Payroll

$99.00

1 99.00

GENERAL LEDGER

149.00

199.00

DATA BASE

MANAGEMENT

SYSTEM

149.00

249.00

NOW OPEN

V R DATA'S Computer

Repair Center

Corp. MORE DA TA PER DOLLAR777 Henderson Boulevard N-6 • Folcroft Industrial Park • Folcroft. PA 19032 • (215)461-5300FOREIGN and DOMESTIC DISTRIBUTORSHIPS AVAILABLE • TOLLFREE1 -(800) 345-8102 Orders only!

BECKIAN E

ALL PRIME QUALITY - NEW PARTS ONLY

SATISFACTION GUARANTEED.

■>■

EDGE CARD CONNECTORS:

GOLD PLATED:

Abbreviations: S/E Solder Eye

. S/T Sold Tail:

W/W Wire Wrap.

PART « DESCRIPTION. Row Sp.

1-9pc.

10 24pcj. 25pcs. Up.

.156'' CONTACT CENTER CONNECTORS.

u

TYPE SUBMINIATURE CONNECTORS.

RRAND:

TEXAS INST.

PART # DESCRIPTION.

Row Sp.

1-9pc.

10-24pcs. 25pcs. Up.

QUANTITY

4070

50I100 ImsailCrom. .250

$3.95ea.

»3.55ea. $3.15ea.

15105

6112 SIEPETINSC

.140

$1.80

♦1.65 $1.45

4090

501100 Imsai WIW .250

4.30ee.

3.65ea. 3.45ee.

15110

6112 SIT PETINSC

.140

1.85

1.65 1.50

MB

SULLINS: IU Rag.

15137

6112 SIT PETINSC

.200

1.60

1.54 1.45

OF

9P

Male $1.60ea. »1.40eo.

$1.30eo.

129BB5

501100 Solder Eye .140

B.BOea.

B.10aa. 5.4500.

15175

61- SIE Sgle Row

1.70

1.50 1.30

l)F

9S

Female 2.25ea. 2.00aa.

1.90ea.

129670

501100 SIT Imsai .250

4.50ea.

4.10ea. 3.70

15270

10120 SIE

.140

2.15

1.95 1.70

OF

1109631

1.2tlo:i.

129875

501100 WIW Imsai .250

5.25

4.75 4.20

15275

10120 SIT

.140

2.00

1.85 1.60

129B85

501100 SIT Altair .140

4.95

4.45 3.95

15435

12124 SIE PET

.140

2.60

2.35 2.10

UA

15P

Male 2.35ea. 2.15ee.

2.00oa.

129990

50/100 SIT Cromam. .250

4.75

4.25 3.60

15440

12124 SIT PET

.140

2.65

2.40 2.15

DA

15S

Female 3.25ee. 3.1 Dee.

2.90ee.

15445

12124 SIT PET

.200

2.75

2.50 2.20

UA

512111

1. pc. Gray Hood 1.40ea. 1.20ea.

1.15ea.

OTHER .

125" CONTACT CTR CONNECTORS

15505

15130 SIE GRI Key

.140

2.50

2.25 2.00

UA

51226-1

2 pc. Black Hood 2.50ea. 2.25oa.

2.00ea.

12305

22144 SIE No Ears .140

4.15

3.75 3.35

15510

15130 SIT GRI Kay

.140

2.40

2.15 2.95

UA

110963 2

2 pc. Grey Hood 1.60ea. 1.35ea.

1.30BB.

12759

36172 SIT .140

5.40

4.65 4.35

15515

15130 WIW GRI Key .200

2.60

2.35 2.10

DBUBUBDBDB

25P25S

512121512261110963 3

Male 2.80ea. 2.60ee.Female 3.60ea. 3.40ea.

1 pc. Grey Hood I.SOea. 1.30ea.

2 pc. Black Hood 1.90ee. 1.65ee.2 pc. Grey Hood 1.75ea. 1.56ea.

2.40BB.3.20BB.1.1 Oea.1.45ea.1.35ea.

12790 40180 WIW .250

.100" CONTACT CTR CONNECTORS:10048 13:26 SiE No Ears .14010280 25150 SIE TRS BO .140

6.30

3.404.50

5.65 5.00

3.05 2.154.05 3.60

1560015610156151570015705

18136 SIE .14018136 SIT .14018136 WIW .20022144 SIE KIMfVEC .14022I44 SIT KIMIVEC .140

3.353.003.602.963.96

3.05 2.702.70 2.403.20 2.902.90 2.753.30 3.00

10175

20140 SIE TRS 60 .140

5.85

5.35 4.75

15710

22I44 WIW KIMIVEC .200

3.49

3.20 2.85

PC

37P

Male 4.20ee. 4.00bb.

3.70ea.

10180

20140 WIW TRS 80 .200

3.30

3.00 2.15

15675

25I50 SIE

.140

4.65

4.20 3.75

DC

37S

5.50ea.

10190

20140 SIT TRS 80 .140

3.20

2.90 2.55

15680

25I50 SIT

.140

4.55

4.10 3.65

nn

110963 4

2 pc. Grey Hood 2.25ea. 2.00bb.

1.75BB.

10485

36172 SIE Vector .140

5.50

4.90 4.40

15685

25I50 WIW

.200

4.65

4.35 3.90

10490

36172 WIE Vector .200

5.80

5.25 4.65

16115

36(72 SIE

.140

6.50

5.85 5.20

uu

50P

Male 5.50ee. 5.1 Uea.

4.758B.

10500

38172 SIT Vector .140

5.70

4.20 4.60

16120

36I72 SIT

.140

6.55

5.90 5.25

DU

50S

FemalB 9.40aa. 8.60ee.

8.00ea.

10535

40180 SIE PET .140

5.B5

5.35 4.75

16125

36I72 W|W

.200

6.75

6.10 5.40

uu

51216-1

1 pc. Gray Hood 2.40ee. 2.20oa.

2. OOee.

10540

40180 WIW PET .200

6.00

5.40 4.60

16145

36I72 SIT

.200

6.50

5.65 5.20

uu

110963-5

2 pc. Grey Hood 2.60ea. 2.40ae.

2.1 Oea.

10550

40160 SIT PET .140

5.80

5.25 4.65

16235

43IB6 SlT Mot 6800 .140

6.60

5.95 5.30

D

20416-2

Herdware Set .90bb. .BObb.11 Hood Sail

.IQbb.

10585

43166 SIE C0SIELF .140

6.95

6.25 5.55

16240

43186 WIW Mot 6800 .200

7.80

7.05 6.25

10605

43186 SIT C0SIELF .140

6.60

5.95 5.30

16260

43186 SIT Mot 6800 .200

6.50

5.65 5.20

10595

43166 WIW C0SIELF .200

6.90

6.20 5.95

16725

43166 SIE Mot 6800 .140

7.20

6.50 5.75

10815

43186 SIT C0SIELF .200

6.80

6.10 5.40

K-1

Pol-Keys

.15

.12 .10

IX. SOCKETS GOLD.

COOLING FANS.

TERMS:

MINIMUM ORDER: $15.00 ADD $1

35 For

WIWRAP 3 TURN

Extra Quiet.

Handling

& Shipping. Orders over $30.00 in the

U.S.A.

$0.40 ea

14 pin

SO.15 ea.

1 to 4

• 18.00 as.

We Pay

the Shipping. CALIF. RESIDENTS: Pie

ise Add

16 pin

0.44 ea

16 pin

0.17 as.

5 to 9

17.00 ea.

6% Sales Tax.

NOTE: NO C.O.D. OR CREDIT CARD ORDERS WILL BE

ACCEPTED.

8OS0A PRIME

55 00 ea.

CONNECTORS Ft

Am,

R CENTRONICS 700 SERIES,henol 57-30360

PHONE: 213-988-6196

MAIL ORDERS TO:

BECKIAN ENTERPRIES

P.O. BOX #3089

EIA 6 CONDUCTOR CABLES 8ft. Long.CLASS #1 Type Cobles.

1. to 4 pes.5 to 9 pes.

$22.0019.00

5 to 9 pes.

6.00 ea.

SIMI VALLEY, CA 93063

Circle 271 on inquiry card.

BYTE May 1980 309

COMPUTERSYSTEMS

J IMC.

15335 South Hawthorne BoulevardLawndale, California 90260(213) 970-0952 s

S D SYSTEMS

EXPANDORAM ST

EXPANDABLE TO 64K USING 4116 RAMS

hMiiMiimmiimi

Interfaces with most popular S-100 boards

Bank selectable; PHANTOM provision

Draws only 5 watts fully populated

Designed to work with Z-80, 8080,and 8085 systems

No wait states required

16K boundaries & protect via dip switches

Kits come with sockets for full 64K

Invisible refresh

MEM-16K (16K KIT) $239.95

MEM-16AT (16K A&T) $289.95

MEM-32K (32K KIT) $309.95

MEM-32AT (32K A&T) $359.95

MEM-48K (48K KIT) $379.95

MEM-48AT (48K A&T) $429.95

MEM-64K (64K KIT) $449.95

MEM-64AT (64K A&T) $499.95

SPECIAL

NOVATION CAT

ACOUSTIC COUPLER/MODEM

$157.50

Let your computertalk to other computers !Bell Systems 103 compatible300 baud, answer or orginate

QT SYSTEMSFURNITURE +

DS4830 48"w X 30"d X 26" h Pecan

or white finish avail $149.95

DS4830-1 48"w X 30"d X 26"h with

Micro-Shelf, Pecan finish $224.95

DS4830-2 48"w X 30"d X 26"h with

Return, Pecan or white finish avail $249.95

DS-810 Printer Stand for Tl 810 $120.00

Look to QT for the

EPROMS

1702A $ 4.95

2708 $ 6.75

2516 $24.00

2716 (Tl) $24.00

2716 (5 VOLT) $24.00

2758 $27.00

2532 $70.00

2732 $70.00

NEW DISK OPERATING SYSTEM

SDOS

SDOS is a CP/M compatible operating systemdesigned for the S D Sales Versafloppy I or II. Itrequires the SBC-100/Versafloppy board set andfunctions as a superset of CP/M giving 19additional functions including the attributes, disklabel and read/write logical blocks. It providesadditional protection features and is expandableto a multi-user real time system. $200.00

Tl PRINTERS

TI810 PARALLEL $1895.00

TI810 SERIAL $1695.00

ZIP'

TEXTOOL

DIP II SOCKETS

I

['^=^1

inn

16 PIN ZIP* DIP II $5.50

24 PIN ZIP* DIP II $7.50

40 PIN ZIP* DIP II 10.25

' ZERO INSERTION PRESSURE

CP/M 2.0

Digital Research has done it again1 This new release of their

industry standard disk operating system is bound to be aneven bigger hit than the original version All of thefundamental file-size restrictions of release 1 have beeneliminated, while maintaining full compatibility with theearlier versions This new release can be field-configured bythe user for a single mini-disk up through a multiple drivehard-disk system with 128 megabyte capacity Fieldconfiguration can be accomplished easily through use of theMacro Library (DISKDEF) provided with CP/M 2 0

A powerful operating system for only ... S150.00

51/4" DISKDRIVES

MPI B-51 $295.00

SHUGART SA400 $295.00

SHUGART 8" 801R $495.00

REMEX RFD 4000 $595.00

HARD DISK

LOBO 10 MEGABYTE For Apple with

controller $4295.00

LOBO 10 MEGABYTE For S-100 withcontroller $4795.00

QT DISKETTES

SOFT SECTOR

5'A" single sided, single density

box of 10 $29.95

SOFT SECTOR

8" single sided, single density

box of 10 $34.95

S D SYSTEMS

Z-80 STARTER KIT

COMPLETE Z-80 MICROCOMPUTER

On-board keyboard, display. EPROM programmer,

and cassette interface

On-board S-1Q0 interface

Wire-wrap area and room tor 2 S-100 connectors

Two 8-bit parallel I/O ports, 4-channel CTC, 5

programmable breakpoints

Examine and change memory. I/O ports, or register

Z-80K (KIT) $279.95

Z-80AT (A&T) $349.95

BEST BUY RATED

TV-1 ONLY $7.95

OUR BEST SELLING R.F. MODULATOR

S D SYSTEMS

SBC-100/200

OR 4 MHz SINGLE BOARD COMPUTER

S-100 bus compatible Z-80 CPU

1K of on-board RAM

4 EPROM sockets accomodates 2708. 2716. or 2732

One parallel and one serial I/O port

4-channel counter timer chip (Z-80 CTC)

Software programmable serial baud rates

SBC-100K (2 MHz KIT) $249.95

SBC-100AT (2 MHz A&T) $299.95

SBC-200K (4 MHz KIT) $289.95

SBC-200AT (4 MHz A&T) $339.95

TRS-80 DISK

DRIVE INCLUDED)

TRS-80 I (5V«") $395.00

TRS-80 II (8 ") $1095.00

APPLE II $1550.00

DISK DRIVE SYSTEMS

S-100

MS-B00-1 (Drive with cables &

power supply) $1095.00

MS-800-2 (2 Drives with cables &

power supply ) $1595.00

SD SYSTEMS

VERSAFLOPPY II

DOUBLE DENSITY DISK CONTROLLER

Single or double density floppy disk controller

985600 bytes on 8" double sided diskettes

259840 bytes on double sided 5','," diskettes

S-100 bus (IEEE) standard compatible

IBM 3740 format in single density

8" and 5V drives controlled simultaneously

Operates with Z-80. 8080. and 8085 CPU's

Controls up to 4 drives

Vectored interrupt operation optional

VF-2K (KIT) $335.95

VF-2AT (A&T) $385.95

APPLE PRODUCTS

APPLE KITS &ASSEMBLED BOARDS

AIO Apple Serial/Parallel Interface

Kit $115.00

Assembled and Tested $155.00

MICRO-MODEM II $350.00

WIZARD CONTROLLER for 8" Disk Drive$360.00SORRENTO CONTROLLER for 8" Apple Disk

Drive $360.00

INTROL X-10 SYSTEM (turns appliances

on/off) $275.00

MICRO-MUSIC (Software) $180.00

AlO/Serial-Parallel Board Kit $115.00

AlO/Senal-Parallel Board A&T $155.00

INTEGER Firmware Card $179.00

PARALLEL INTERFACE CARD $90.00

VISICALC(Busmess Software Package) $124.95SUPER-MOD II (connects Apple to TV). $25.00ROM WRITER (Epromburner) Mountain

Hardware (order) $175.00

PROGRAMMER AID #1 $50.00

APPLE CLOCK $280.00

SANYO 15" MONITOR $295.00

MODEL 920 TELEVIDEO

SMART (CRT)TERMINAL

• Reverse Video

• Blinking/blank fields•Upper/lower case character

• Protected fields•Non-glare screen

• Underlining

• 12x10 character res.•Function/editing keys•Blinking cursor•Typewriter/TTV keyboards•Numeric pad

•9 Baud rates (75-9600 Baud)•Sell-test

• Auxiliary portSALE PRICE $895.00

Freight charge $20.00

QT MEMORY EXPANSION KITS

FOR

TRS-80 APPLE EXIDY

4116-200 ns

Expansion Kit

100 pes

1,000 pes

$60.00 ea.. $5.95 ea.. $5.25 ea.

MICROPROCESSORS

Z80 (2 MHz) $10.95

Z80A (4 MHz) . . $12.95

6502 $11.25

6B00 $12.50

6802 $19.50

8035 $20.00

8035-8 $20.00

8080A $ 3.95

8085A $20.00

8086-4 $60.00

8748-8 $70.00

8080A SUPPORT

8212 $ 4.50

8214 $ 4.50

8216 S 2.95

8224 $ 4.00

8238 $ 6.00

8243 $ 5.00

8251 $ 7.00

8253 $19.00

8255 $ 6.25

8257 $17.95

8259 $19.95

8275 $69.95

8279 $17.50

8295 $16.50

STATIC RAMS

21L02 (450 ns)

64 ea./$1.20 ea.

100ea./$1.10 ea.

1,000 ea./$.95 ea.

2102-1 $1.35

2114L (450 ns) $5.25 ea.

100 ea./$4.75 ea.

2114L (300 ns) $5.50 ea. 100 ea./$4.50 ea.

UARTS

TR1602B $ 3.75

BAUD RATEGENERATOR

MC14411P $10.00

CHARACTERGENERATORS

2513 (Upper case) $10.952513 (Lower case) $10.952513 Upper (5 v) $ 9.752513 Lower (5 v) $10.95

2516 (Slg) $13.00

6571 $13.00

6571AP $10.95

MATCHLESS

FEATURES PRINTERS

• Documentation included

• 132 columns, 63 lines per minute, Bi-Directional,Nominal Thruput

• High Reliability - Heavy Duty Cycle, 100 MillionCharacters Print Head Life

• Sprocket Feed

• 9x7 Dot Matrix Character Front

SALE PRICE WITH CABLE

FOR TRS-80 I $795.00

FOR TRS-80 II $795.00

FOR APPLE "$849.00

FOR S-100 $795.00

"Includes parallel interface with documentation

Add freight $20.00

==fit PRODUCTS

S-100 BARE BOARDS

CB1A 8080 CPU $30.95

VB1B Memory Mapped Video Interface .. $26.95

VB2 I/O Mapped Video Interface $29.95

I02 Parallel I/O Interlace $34.00

I04 2P + 2S I/O Interface $26.95

SB1 Music Synthesizer $39.95

OB1 Vector Jump & Prototyping Board .. $29.95

MB6B 8K Static RAM $25.95

MB7 Low Power 16K Static RAM $26.95

MBB 4K 1702 EPROM Board $29.95

MB8A 16K 2708 EPROM Board $34.95

T1 Terminator $26.00

MTI 15 Slot Motherboard $45.00

XB1 Extender Board $13.50

—ssn SOFTWARE, FIRMWARE,——*" MANUALS, MISC.

SMM 8080 Monitor (on two 2708s

or eight 1702s) $50.00

AIO Apple Parallel Interface Firmware ... $25.00

AIO Apple Pascal Patcher Disk $25.00

SB1 Music Synthesizer Software

Paper Tape of MUS-X1 Interpreter $ 9.00

CP/M Compatible 8" Disk, containing

• MUS-X1 Music Interpreter

• Test Program

• 18 Encoded Music Selections $25.00

SB1 Booklet (with 21 Encoded Music

Selections) $10.00

Manuals

SB1 Music Synthesizer Manual $10.00

All Other Manuals $ 5.00

100 Pin edge connector (short st) $ 3.00

100 Pin edge connector (standard ww) .. $ 4.00Card Guides $ .15

S-100 KITS &ASSEMBLED BOARDS

CB1A 8080 CPU

Kit $129.95

Assembled & Tested $189.95

CB2 Z-80 CPU

Kit $185.95

Assembled & Tested $250.00

VB1B Memory Mapped Video Interface

Kit $125.00

Assembled & Tested $180.00

VB2 I/O Mapped Video Interface

Kit

$150.00

Assembled & Tested

$195.00

VB3 80 Character Video Interface

80x24 Display, 2 MHz

Kit .

. $299.95

. $389.95

80x24 Display, 4 MHz

Kit

. $324.95

$410.00

Upgrade Kit for 80x51 Display

2 MHz

. $ 69.00

4 MHz

$ 89.00

I02 Parallel I/O Interface

Kit

$ 59.00

Assembled & Tested

. S 89.00

I04 2P + 2S I/O Interface

Kit

$126.00

Assembled & Tested

$199.95

SB1 Music Synthesizer (4)

Kit

$199.00

. $279.00

OB1 Vector Jump & Prototyping Board

Kit

$ 55.00

Assembled & Tested

.$ 85.00

MB6B 8K Static RAM

450 ns RAM

Kit

$129.95

.$149.95

250 ns RAM

Kit

$159.95

Assembled & Tested

. $224.95

MB7 Low Power 16K Static RAM

Kit

. $269.96

Assembled & Tested

. $375.00

PB1 2708/2716 EPROM Programmer

Kit with Textool sockets

$129.95

Assembled & Tested with Textool sockets$175.00

MB3 4K 1702 EPROM Board

Kit - without EPROMs

$ 65.00

Assembled & Tested

$125.00

MB8A 16K 2708 EPROM Board

Kit - without EPROMsAssembled & TestedT1 Active Terminator

Kit $ 34.00

Assembled & Tested $ 64.00

MT1 15 Slot Motherboard

Kit (with Connectors) $129.95

Assembled & Tested $149.95

XB1 Extender Board

Kit (with Connector) $

Assembled & Tested $

19.9529.95

COMPUTERSYSTEMS

j IMC.

15335 South Hawthorne BoulevardLawndale, California 90260(213) 970-0952

PLACE ORDERSTOLL FREE1-800-421-5150(CONTINENTAL U.S. ONLY)

Buy Direct From CompuMart

COMPUMART NOW OFFERS THEENTIRE DEC LSI-11 PRODUCT LINECALL FOR PRICES & DELIVERY.

Buy Direct from the LargestCommodore Dealer in the Country— NCE/CompuMart.

8K-Keyboard N $795

16K-Keyboard B $995

16K-Keyboard N $995

32K-Keyboard B $1,295

32K-Keyboard N $1,295

B — large keyboard (graphics not on keys)N — large keyboard with graphics symbols

SUPER SAVER. Thanks to Commodore

their printer prices have been drastically

reduced:

Commodore Printer (tractor feed)

was $995 NOW $795Commodore Printer (friction feed)

was $849 NOW $695

2 Good reasons for buyingyour PET" from CompuMart:

(1) $100 IN FREE ACCESSORIESWITH 16K or32K PET.

When you buy a 16K or32K PET, apply $100 towardPET accessories. FREE. Choose from the acces-sories listed below and indicate on your order thatyou have reduced the cost of your accessories by$100.

(2) FREE WITH PURCHASEOF ANY PET( Offer extended

until May 15,1980)

A Texas Instruments' Hex/Octal Calculator /"'■CjJ*($60 Value), and a set of 6 PET Workbooks(Worth $36).PET Accessories

Commodore Dual Floppy Disk Drive S1.295.00

Second Cassette—from Commodore $95.00

Commodore PET Service Kit $30.00

Beeper—Tells when tape is loaded $24.95

Petunia—Play music from PET $29.95

Video Buffer—Attach another CRT $29 95

Combo—Petunia abd Video Buffer S49.95

TNW Bi-Dir.RS-232 printer 3-iace $229.00

KIM 1 (A Single Board Computer

from Commodore) S179.00

PET TO IEEE Cable $39.95

IEEE TO IEEE Cable S49.95

KIM1 & Power Supply Package Special . . $200.00

NEW FROM EXIDY

THE SORCERER II 48K COMPUTER

Z-80 Microprocessor, Full-sized keyboard • ROM PACPrograms • Microsoft BASIC • Powerful Graphics •Serial and Parallel I/O • Dual Cassette I/O MemoryInternally Expandable • S-100 Expansion Options.48K Sorcerer II $1,395

CENTRONICSPRINTERS

The 779-2 is a tractorfeed printer designedtor small businesssystems. Uses a 5x7dot matrix to produceall 64 upper caseASCII characters.Centronics is the big-gest name in printersand this is their mostpopular model.

List. $1,245

SALE! $1,079

The New 730-1 parallel matrix printer is ideally suited forall personal and microcomputer systems. StandardFeatures include: 100 cps • 80 char./line • 3-way paperhandling system • 7x7 dot matrix • 96 character ASCII •

List $995 SALE! $839

To meet our Centronics' quotas we are ottering thesegreat specials on their printers!

753-9 9x9 Data Processing Printer. List: $2,995 SALE!$2,395

704-9 9 x 9 180 CPS. List: $1,995 SALE! $1,750701-9 9x9 Matrix. List: $1,595 SALE! $1,395730-3 Serial 730. List: $895 SALE! $745Brand New. Centronics Model 737, the first printer in Itsclass capable of offering print quality suitable for textprocessing, plus the performance & application flexi-bility required for data processing. Unbelievable qualityof type.

737-3 Serial Word Processor Printer $1,045

737-1 Parallel Word Processor Printer $995

The Perfect Printer for Small Business Systems

CompuMart

Commodore's 3 for 2 is Back!

SPECIAL OFFER TO EDUCATORS - GET

A FREE PET COMPUTER

For a limited time only, when your school buys any 2;PET's at the regular list (see our PET'" prices listedlabove), Commodore will include another PET in the'deal, absolutely FREEI Call CompuMart TOLL-FREE lorcomplete details.

The Paper TigerPrinter FromIntegral Data

'k i

»oA/l!

Siartdard featuresinclude:4character8.3 to 16.5 cpi •56 cps at 10 char,per in. • Selectableline spacing •8 switch-selectableform sizes.

The IDS Graphics Option for the PaperTiger allows full dot pattern control andincludes an expanded 2048-byte buffer(a 256-byte buffer is standard).

IDS Paper Tiger Printer $995

IDS Graphics Paper Tiger Printer $1,094

SANYO MONITORS

9-inch

reg.$199

SALE! $169

15-inch

reg.$299

SALE! $269/

Perfect for Apple users...Sanyo Cassette Recorder $55

We've Had a Reputation forDependability Since 1971.

DEPT. BY50, 270 THIRD ST., CAMBRIDGE,MA. 02142

To Order: 1 (800) 343-5504

In Mass: 1 (617) 491-2700

MemberComputerI Dealers

Assoc.

We have a complete inventory of Apple computers, peri-pherals, & software In-Stock for immediate delivery —

$200 in FREE accessories with the purchaseof a 4BK Apple II reg. or Apple II plus.

16K Apple reg. or plus — $1,195 ($100 in free acces.)32K Apple reg. or plus — $1,395 (S150 in free acces)48K Apple reg. or plus — $1,495 (S200 in free acces.)Apple Accessories

PASCAL $495

Micromodem $379

VisiCalc $150

The Controller (Business Package) SALE! S550

The Cashier (POS System) SALE! $200

Integer BASIC ROM Card $200

Centronics Printer Interface $225

Disk and Controller $595

Parallel Printer Card S180

Communications Card S225

Hi-Speed Serial Card S195

Firmware Card S200

NEW! AppleWriter Text Editor $75

NOVATION CAT™

ACCOUSTIC MODEM

• Answer Originate • Bell 108

• 300 Baud • Low Profile Design

Looks good, works great! <j-l 7Q r\r\

ZENITH

EXCLUSIVE

FROM

COMPUMART!

COLOR VIDEO MONITOR

Beautiful Display Capabilities. Excellent for use withApple, Atari, & Sorcerer Computers. This 13-inchmonitor is Zenith's first color video displaydesigned specifically for computers. Featuresinclude color and degaussing circuits.Zenith Color Monitor $499.00

HAZELTINE TERMINALS ATSPECTACULAR SAVINGS!

wJ

R

Hazeltine 1410-TTY-style keyboard, 8 baud ratesfrom 110 to 9600. 12" screen, 24x80 display. 5x7 dotMatrix Upper Case ASCII character set. 12-key

numeric keypad. List Price $895 SALE! $779

Hazeltine 1500 — 8 baud rates from 110 to 19,200and ANSI Standard Keyboard, EIA RS-232. All 94Upper/Lower Case characters in a high resolution7x10 matrix display. Much more.

List Price $1,145 SALE! $995

Hazeltine 1520 — Take advantage of this $310savings while it lasts! The Hazeltine 1520 is a power-ful multi-processor terminal.List Price $1.585 SALE! $1,275

r-

THE SINGLE BOARDDEVELOPMENT SYSTEMROCKWELL AIM 65

6502 Microprocessor • 20-character, alpha-numeric LEDdisplay ■ Full-size 54-key keyboard with 3 user-definedfunctions * Fast, on-board 20-column thermal printer» 8KAdvanced Interactive Monitor program • Dual cassetteinterface board • On-board timer • On-board ROM ex-pansion to 12K • 4K on-board RAM ■ On-board TTYinterface • 16 parallel 1/0 lines • One serial 1/0 port ■ KIM-compatible edge connectors for even further memory or1/0 expansion.

The CompuMart AIM System combines all of our optionsfor the AIM to give you the capabilities of developmentsystems costing 5 to 10 times as much. This systemincludes a 4K AIM 65 with BASIC and Assembler, an MTUpower supply, a Sanyo tape recorder and an EGI Enclo-sure for the AIM.

CompuMart AIM System $785.00

4K AIM-65 $450.00

Paper for the AIM $4.75

312 BYTE May 1980

Circle 273 on inquiry card.

10-DAY FREE TRIAL

SEND FOR OURFREE CATALOG

Lear Siegler Terminals& Printers atTremendous Savings

ADM-3A. Industries'

favorite dumb terminal forsome very smart reasons.12" dianonal screen • Fullor half duplex operation at11 selectable data rates •1,920 easy-to-read char-acters in 24 rows of 80letters • RS-232C inter-face extension port •Direct cursor addressing.

Reg Price. S895

Sale! CALL

/

A

MB

ADM-31. A terminal that's too smart to be considereddumb. Comes complete with keyboard, control logic,character generator, refresh memory & interlace •Displays two pages of text instead ot one • Field protectmode • Factory installed selected parameters.Reg. Price. S1.450 Sale! CALL

ADM-42 with Keyboard. Reg. Price. $1,795Sale! CALL

ADM-42 without keyboard. Reg. Price. $1,595

Sale! CALL

Model 310 Ballistic Printer (Serial/Parallel)

Reg Price $2.045 Sale CALL

The remarkable TI-99/4 Home Computer. Compare it.

Dollar for dollar. Feature for feature.

Superior color, music, sound & graphics-and a powerful

extended BASIC - all built in. Plus a uniqe new Solid

Slate Speech u Synthesizer and Tl's special Solid State

Software. "

Comes complete with the Features you want:

• Powerful TI-BASIC

• Up to 72K total memory capability - 16K RAM, 26KROM plus up to 30K ROM in Tl's Solid State SoftwareCommand Modules.

• 16 - color graphics capability

• Music & sound effects

• Built-in equation calculator

• High quality 13" color monitor

Call our Sales Dept. for Complete Description & Specs.

TI-99/4 Home Computer w/Monitor $1,050.

TI-99/4 Home Computer w/o Monitor $8.95.

Tl User Reference Manual $9.95.

Tl CALCULATORS - Three of the finest from the lirst.

Tl Programmable 59 $245.00

TI-58C Programmable Calculator

{w/contlnuous memory) $104.00

Tl Programmer $59.00

Add convenient versatile printing capabilities to your TlProgrammable 58C or 59 calculator with the PC-100Cthermal printer, plotter.

Tl PC-100C 168.00

Tl Talking Translator. The translator that actually speaks!$300.00 Language Modules for the Tl Translator $49.95Ea. Available in : Spanish. French, English & German.SPEAK & SPELL" - Tl's remarkable learning aid withelectronic voice & brain. &69.95 Modules for Speak 8,Spell $17.95 Ea: Super Stumpers (grades 4-6), VowelPower (Ages 7 8. up), Super Stumpers (Grades 7 & 8)

ADDITIONAL TI-99/4 ACCESSORIES

Speech Editor $99.95

Demonstration $69.95

Diagnostic $29.95

Joysticks $29.95

Speech Box $149.95

Dual Cassette Cable $19.95

Math Dictionary $29.95

Beginners Basic $9.95

SOLID STATE SOFTWARE COMMAND MODULESEntertainment:

• Football $29.95

• Video Chess $69.95

• Video Graphs $19.95

Home Management/Personal Finance:

• Home Financial Decisions $22.95

• Household Budget Mgt $44.95

Education:

• Early Learning $29.95

• Physical Fitness $29.95

• Number Magic $19.95

• Beginning Grammar $29.95

300 Series BallisticPrinters. This application-oriented matrix printer isbuilt to last. Featuresinclude: Ballistic Printing• Positive 180 cps • Bi-directional Printing • Acharacter buffer that isoptionally expandable to2.048 characters • 512character buffer standard.

We Stock Lear SieglerAccessories —Call For Details.

ADM-42. The semi-intelligent terminalthat providesyouwithflexibility of format.security, editing,interface, and trans-mission. Two-pagedisplay standard(Optionally expand-able toeight) • Blank-ing, blinking, andreverse fields • Threeways to TAB • 16Function keys do thework of 32 • Detach-able keyboard.

A Calculator, A system, A WholeNew Standard.

The finest calculators available forScience, Engineering, & Business.

HEWLETT-PACKARD'S HP-41C

The Calculator.

Features over 130 functions and offers up to 400 lines ofprogram memory or 63 data storage registers —expandable to 319 registers or up to 2,000 lines. RPNLogic. Alpha-numeric capabilities let you communicatewith (he calculator in English. Customization featuresallow you to totally reassign the keyboard functions.Continuous memory HP-41C Calculator $288.00

The System.

Memory Modules. For storing programs or up to 2,000

lines of program memory $45.00

"Extra Smart" Card Reader. Records programs and data

back onto blank mag-cards $179.00

The Printer. Upper and Lower case. High resolution i

plotting. Portable. Thermal operation $320.00 i

Apohcation Modules $45.00 EACH.

Standard pac. Statistics, Math, Financial. & Surveying.

HP SERIES ECALCULATORSHP-31E — Scientific.

Trigonometric, exponen-tial & math functions.

$49.95

HP-32E — AdvancedScientific with Statistics.All HP-31E functions plushyperbolies and compre-hensive statistics $66.95HP-33E — ProgrammableScientific. A program-mable science, math andstatistical calculator.

$79.95

Also available with con-tinuous memory.. . .86.40HP-37E — BusinessManagement. Best choicefor a business/financecalculator $69.95

HP-38E — Advanced Financial with Programmability. Allthe features of the HP-37E plus a lot more power.

$108.00

Also available with continuous memory $144.95

THE ALL NEW HP-34C. Advanced Continuous MemoryScientific Programmable with an impressive array ofprogramming features $144.95

CompuMart STOCKS THE COMPLETELINE OF MATROX PRODUCTS.CALL FOR SPECS.

Based on our policy of offering ourcustomers only the finest in micro-computers, CompuMart is pleased toannounce that we now carry the newgeneration of Personal Computers byAtari.

INTRODUCTORY SPECIALS

To celebrate our commitment to Atari, we are offering the

following Atari Specials:

(1) Buy additional memory for your computer, 8K or 16K,

and we will double the amount of memory FREE!

(A potential savings of $200.)

(?) Buy the Atari 800 Computer and take $100 off the

purchase price of the Atari 810 Disk Drive or the Atari 820

printer.

ATARI 800PERSONAL COMPUTER SYSTEM

Comes with:

• Computer Console

• BASIC Language Cartridge

• Education System Master Cartridge

• BASIC Language Programming Manual

• 800 Operator's Manual

• ATARI 410 Program Recorder

■ Invitation to Programming Cassette

• 8K RAM Memory Module '

• 10K ROM Operating System

• Power Supply

• TV Switch Box

SPECIFICATIONS:

High resolution color graphics

57 key full stroke keyboard

Built-in RF modulator for channel 2/3 operation with

standard TV set

Composite video output for use with monitor

Internal Speaker

Two cartridge slots for rapid program insertion

Four internal slots for expansion up to 48K RAM

6502B Microprocessor

High speed serial 1/0 port

Atari 800 Computer System S995.95

ATARI 820 PRINTER

High resolution dot matrix impact printer

Uses standard 3/a inch roll paper and ribbon

40 characters per line

Speed: 40 characters per second

UL approved

Atari 820 Printer $599.95

ATARI 810 PRINTER

Uses standard 5V4 inch diskettes

8BK bytes storage per diskette

Up to four disk drive units can operate with the system

Average data access time: 236 milliseconds

Power: AC adapter: UL approved

Atari 810 Disk Drive $699.95

Upgrade your computer with additional memory. (Notethat the Atari 800 Computer comes with 8K ol RAMmemory and will accept up to 48K.)

. $124.95. $199.95

Atari 8K RAM Memory Module .Atari 16K RAM Memory Module

CompuMart important oi

■"" All orders musl include 4°« shipping and handling. Mass residen

Dept. BY50 , 5°o sales tax. M.ch residents 4% lor sales tax

270 Third St., Phones open from 8 30 a m to5'30p m. EST. Mon Fri -PO sac<

^ . . _ U,»~«- 'rom O&B ralBd COmpamp^- chmmonl rnntmnonl imnn re«

^#amoriage, Mass. signed purchase order-

02142 Mosl items in stock for Immediate sniprneni- can Tor uem

In the Ann Arbor area7 Our retail store is open 11 00 am. to 7 0TO ORDER CALL: Tues-Fr, 1000am to 500 pm Saturdays (closed Sun and Mi

1 -800-343'5504 'IF NOT SATISFIED RETURN PURCHASl

IN MASS. CALL: (617) 491-2700 WITHIN 10 DAYS FOR A FULL REFUND.

Circle 273 on inquiry card.

BYTE May 1980 313

1.75

7400 TTL

SN7470N .29

SN7472N .29

SN7473N .35

SN7474N .35

SN7475N .49

SN7476N .35

SN7479N 5.00

SN7480N .50

SN74B2N .99

5N7483N .69SN7485NSN7486NSN7489N

SN7490N .45

SN7491N .59

SN7492N .43

SN7493N .43

SN7494N .55

SN7495N .55

SN7496N .65

SN7497N 3.00

SN74100N 1.25

SN74107N .35

SN74109N .59

SN74116N 1.95

SN74121N .35

SN74122N .39

SN74123N .59

SN74125N .49

5N74126N .49

SN74132N .75

SN74136N .75

SN74141N .79

SN74142N 2.95

SN 74143 N 2.95

SN74144N 2.95

SN74145N .79

SN74147N 1.95

SN74148N 1.29

SN74150N 1.25

SN74151N .59

5N74152N .59

SN74153N .59

SN741S4N 1.50

SN74155N .79

SN74156N .79

5N74157N .65

SN74160N .89

SN74161N .89

SN 74162 N 1.95

SN74163N .89

SN74154N .89

SN74165N .89

SN74166N 1.25

5N74167N 1.95

SN74170N 1.59

SN74172N 6.00

SN74173N 1.25

SN74174IN 1.00

SN 74175 N 1.00

SN74176N .79

SN74177N .79

SIN 74179 N 1.95

SN 74180 N .79

SN741B1N 1.95

SN74182N .79

SN74184N 1.95

SN7418SN 1.95

SN74186N 9.95

SN74188N 3.95

SN74I90N 1.25

SN74191N 1.25

SN74192N .79

SN74193N .79

SN74194N .89

SN74195N .69

SN74196N .89

SN74197N .89

SN 74198 N 1.49

SN 74199 N 1.49

SN74S200 4.95

SN74251N .99

SN74279N .79

SN74283N 2.25

SN74284N 3.95

SN74285N 3.95

SN74365N .69

SN74366N .69

SN743S7N .69

SN 74368 N .69

SN 74390 N 1.95

SN 74393 N 1.95

CD4000CD4001CD4002CD4006CD4007CD4009CD4010CD40I1CD4012CD4013CD4014CD4015CD4016CD40I7CD4018CD4019CD4020CD4021CD4022CD4023CD4024CD4025CD4026CD4027

CMOS

CD4028CD4029CD4030CD4035CD4040CD4041CD4Q42CD4043CD4Q44CD4046CD4047CD404SCD4049CD4050CD4051CD4053CD4056CD40S9CO4060CD4066CD4068CD4069

1.792.501.35

CD4O70 .55

CD4071 .49

CD4072 .49

CD4076 1.39

CD40S1 .39

C D4082 .39

CD4093 .99

CD4098 1.19

MC14409 14.95

MC14410 14.95

MC 14411 14.95

MC 14419 4.95

MC14433 13.95

MC 14506 .75

MC 14507 .99

MC14562 11.95MC 14583CD4508CD4SI0

CD4511 1.29

CD4515 2.95

CD4518 1.29

CO4520 1.29

CD4566 2.25

3.95

74C0O74C0274C0474C0B74C1074C1474C2074C3074C4274C4874C7374C74

74C00

74C8574C9074C9374C9S74C10774C15174C15474C15774C16074C161

74C16374C16474 C17374C19274C19374C19574C92274C92374C92574C92680C9S80C97

J.50

78MG 1.75

LM106H .99

LM300H .80

LM301CN/H .35

LM302H .75

LM304H 1.00

LM305H .60

LM307CN/H .35

LM308CN/H 1.00

LM309H 1.10

LM309K 1.25

LM310CN 1.95

LM311N/H .90

LM312H 1.95

LM317K 6.50LM318CN/H1.5Q

LM319N 1.30

LM320K-5 1.35

LM320K-S.2 1.35

LM320K-12 1.25

LM320K-15 1.35

LM320K-18 1.35

LM320K-24 1.35

LM320T-5 1.25

LM320T-5.2 1.25

LM320T-B 1.25

LM320T-12 1.25

LM320T-1S 1.25

LM320T-18 1,25

LM320T-24 }.25

LM323K-5 5.95

LM324N 1.49

LM339N .99

LM340K-5 1.35

LM340K-6 1.35

LM340K-8 1.35

LM340K-12 1.3S

LM340K-15 1.35

LINEAR

LM340K-18 1.35

LM340K-24 1.35

LM34QT-5 1.25

LM340T-6 1.25

LM340T-8 1.25

LM340T-12 1.25

LM340T-15 1.25

LM340T-18 1.25

LM340T-24 I.2S

LM358N ' 1.00

LM370N 1.95

LM373N 3.2S

LM377N 4.00

LM380N 1.25

LM380CN .99

LM381N 1.79

LM382N 1.79

NE501N 8.00

NE510A 6.00

NE529A 4.95

NE531H/V 3.95

NE536T 6.00

NE540 6.00

NE544N 4.95

NE550N 1.30

NE555V .39

NE556N .99

NE560B 5.00

NE562B 5.00

NE565N/H 1.25

NE566CN 1.75

NE567V/H .99

NE570N 4.95LM703CN/H .69

LM709N/H .29

LM710N .79

LM711N .39

LM723N/H .55

LM733N 1.00

LM739N 1.19LM74ICN/H .35

LM741-14N .39

LM747N/H .79

LM748N/H .39

LM1310N 1.95LM1458CN/H.59

MC1488N 1.95

MC1489N 1.95

LM1496N .95

LM1556V 1.75

MC1741SCP 3.00

LM2111N 1.95

LM2901N 2.95

LM3053N 1.50

LM3065N 1.49LM 3900 N (3401).59

LM3905N 1.49

LM3909N 1.25

MC5558V .59

8038 B 4.95

LM75450N .49

75451CN .39

75452CN .39

7545 3CN .39

75454CN .39

75491CN .79

7549 2CN .89

75493N .89

75494CN .89

RC4136 1.25

RC4151 3.95

RC4194 4.95

RC4195 4.49

74LS0074LS0174US0274LS0374LS0474LS0574LS0874LS0974LSI074'LSll74LS1374LS1474LS1574LS2074LS2I74LS2274L52674LS2774LS2874LS3074LS3274LS3774LS4074LS42EJ4LS47

.35

74LS00TTL74LS5174LS54

74LS5S74LS7374LS7474LS7574LS7674LS7874LS8374LS8574LS8674LS9074LS9274LS9374LS9574LS9674LS10774LS10974LS11274LS12374LS12574LS13274LS13674LS138

74LS13974LS15174LS15574LS15774LS16074LS16174LS16274LS16374LS16474LS17574LS18174LS19074LS19174LS19274LS19374LS19474LS19574L525374LS25774LS25B74LS26074LS27974LS36774LS36874LS670

aCromemcoincorporated

Z80-4MHz Single Card Computer

CimiMmcii'i Singlt Cud Ccm

ThD cird ulli.i 4 HHl npculioii. BK favti! ill mi baud 2716 PUDM. md IKhyK Di attic HAM mtroo.Y- Ttm itii.il algut cvH ilu niovidM in IIS 232(si 20mA curttnl loop I itiiit inltilicc with cio;iimmibli biuD* it Hi (a76.900, vtclninj inrtnunti, 24 bin ol bidinciiorul pmlld 1/0. ind 5 pin-ji.niinilile tirnen. Only « power uiPIHy mil PI10M toltwiit m nqu.red laroperaliDi.. Thi Single Cud Computer ii lis*inbltd md If ncd (Model SCC-W)>i MS0, Ih( Mom l or ind CoMiol BASIC ait •viriibtt in lura ROM'i IMsdtl

MC81I

SCC-W iA5sembied) $450.00

DISCRETE LEDS

XC556R .200" red

XC5S6G .200" green

XC5S6Y .200" yellow

XC556C .200" clear

XC22R .200" red

XC22G .200" green

XC22Y .200" yellow

MV10B .170" red

5/S14/$l4/$l4/Jl,5/$l4/$l4/514/$l

MV50 .085" red

XC209R .125" red

XC209G .125" green

XC209Y .125" yellow

XC526R .185" red

XC526G .185" green

XC526Y .185" yellow

XC526C .185" clear

6/$l5/S14/$l4/$l5/tl4/$l4/$l4/$l

XC111R .190" redXC111G ,190" greenXC111Y :i90" yellowXC111C .190" clear

DISPLAY LEDS

TYPE

MAN 1MAN 2MAN 3MAN 4MAN 7GMAN 7YMAN 72MAN 74MAN 82MANB4MAN 3620MAN 3630MAN 3540MAN 4610MAN 4640MAN 4710MAN 4730MAN 4740MAN 4810MAN 4840MAN 6610MAN 6630MAN 6640MAN 6650MAN 6660MAN 6680MAN 6710

POLARITY

Common Anodo-red5 x 7 Dot MairU-redCommon Cathode-redCommon Caittode-redCommon Anode-greenCommon Anode-yellowCommon A node-redCommon Cathode-tedCommon Anode-yellowCommon Cathode-yellowCommon An ode-orangeCommon Anode-orange - 1Common Cathode-orangeCommon Anode-orangeCommon Cathode-orangeCommon Anode-redCommon Anode-red t 1Common Cathode-redCommon An ode-ye I lowCommon Cathode-yellowCommon Anode-orange-O.DCommon Anode-orange ± 1Common Cathode -orartge-DCommon Cathode-orange -Common Anode-orangeCommon Cathode-orangeCommon Anode-rod-D.D.

TYPE

MAN 6730

MAN 6740

MAN 6750

MAN 6760

MAN 6780

DL701

DL704

DL707

DL72B

DL741

OL746

DL747

DL749

DL750

DL33B

FND70

FND350

FND359

FN0503

FND5Q7

5082-7730

HDSP-3400

HDSP-3403

5082-7300

5002-7302

5082-7304

5082-7340

POLARITY

Common Anode-red ± 1Common Calhode-red-D.D.Common Calhode-red =: 1Common A node-redCommon Cathode-redCommon Anode-red = 1Common Cathode-redCommon An ode-redCommon Cathode-redCommon Anode-redCommon Anode-red ± 1Common Anode-redCommon Cathode-red * 1Common Calhode-redCommon Calhode-redCommon CathodeCommon Cathode ft 1Common CalhodeCommon Calhode(FND500)Common Anode 1FND510;Common Anode-redCommon Anode-redCommon Calhode red4 x 7 sgl. Digit-RHDP4 x 7 Sgl. Digil-LHDPOvonange chaiacter ( = 1)4x7 Sgl. Digit-Hexadecimal

1.501.50

19.9519.9515.0022.50

RCA LINEAR

CA3013T 2.15

CA2023T 3.25

CA3035T 2.48

CA3039T 1.35

CA3046N 1.30

CA3059N 3.25

CA3060N 3.25

CA3080T 1.25

CA30B1N 2.00

CA3082N 2.00

CA3083N 1.60

CA30S6N .85

CA3089N 3.75

CA3130T 1.39

CA3140T 1.25

CA3160T 1.25

CA3401N .59

CA3600N 3.50

CALCULATORCHIPS/DRIVERS

MM 5725 $2.95

MM5738 2.95

DM8864 2.00

DM8865 1.00

DM8887 .75

9374 7-seg.

LED driver 1.50MM5309 4.95

LOW PROFILE(TIM) SOCKETS

14 pin

IP

16 pin

LP

18 Pin

LP

20 pin

LP

22 pin

LP

24 pin

1 P

28 Pin

LP

36 pin

LP

40 pin

LP

SOLDERTAIL (GOLD)STANDARD

8 oln SG14 pin SG16 pin SGIB pin SG24 pin 5G28 Pin SG36 pin SG

CLOCK CHIPS

MM5309 4.95

MM5311 4.95

MM5312 4.95

MM5314 4.95

MM5316 6.95

MM531B 9.95

MMS369 2.95MM5387/1998a 4.95

CT 7001 6.95

MOTOROLA

MC1408L7 4.95

MC140BL8 5.75

MC1439L 2.95

MC3022P 2.95

MC3061P 3.50MC4016 (74416)7.50

MC4024P 3.95

MC4040P 6.95

MC4044P 4.50

SOLDERTAIL

STANDARD {TIN)

14 pin 5T16 pin ST18 Pin ST24 pin ST28 pin ST36 pin ST40 pin ST

WIRE WRAP SOCKETS(GOLD) LEVEL #3

8 pin WW10 pin WW14 pin WW16 pin WW18 pin WW20 pin WW22 pin WW24 pin WW2B pin WW36 pin WW40 pin WW

1/4 WATT RESISTOR ASSORTMENTS -5%

ASST. 1ASST. 2ASST, 3ASST. 4ASST. 5

10 OHM27 OHM

68 DHM

I? OHMJ3 OHM82 OHM

15 OHM IB OHM 22 OHM39 OHM 47 OHM 56 OHMIO0OHM 120 OHM 150 OHM

loo ohm eaeoHM 270 ohm 330 ohm 390 ohm

■170 OHM 560 OHM 680 I1HM 820 OHM

t.?K 1,5k i.SK 2.2k

tflOK270K

680K

ASST. 8R Includes Resistor Assortments 1 -7 (350 PCS

so pes $1.75

so pes 1.75

1.75

1.75

1.75

1.75

50 pcs 1.75I $9.95 ea.

50 PCS50 PCS50 PCS50 PCS

$10.00 Min. Order - U.S. Funds Only Spec Sheets — 254

Calif. Residents Add 6% Sales Tax 1980 Catalog Available -Send 41 istamp

Postage —Add 5% plus$1 Insurance (if desired)

FREE1980

J a

PHONE

ORDERS

WELCOME

(415) 592-8097

MAIL ORDER ELECTRONICS - WORLDWIDE1355 SHOREWAY ROAD, BELMONT, CA 94002 PRICES SUBJECT TO CHANGE

TELEPHONE/KEYBOARD CHIPS

AY-5-9100 Push Button Telephone Dialler

AY-5-9300 Repertory Dialler

AY-5-95O0 CMOS Clock Generator

AY-5-2376 Keyboard Encoder (88 keys)

HD0165 Keyboard Encoder (16 keys)

74C922 Keyboard Encoder (16 keys)

74C933 Keyboard Encoder (20 keys)

1.95 1

S14.14.954.9514.95

ICM7045ICM7205ICM7207ICM7208ICM7209

ICM CHIPS

CMOS Precision TimerCMOS LED Stopwatcn/TimerOscillator ControllerSeven Decade CoonterClo'ck Generator

24.9519.95

7.5019.95

6.95

NM0S READ ONLY MEMORIES

MCM6571 128 X 9 X 7 ASCII Shitted with Greek 13.50

MCM6574 128 X 9 X 7 Math Symbol S Pictures 13.50

MCM6575 128X9X 7 Alpha Control Char. Gen 13.50

TL074CN

TL494CN

TL496CP

11C90

95H90

4N33

MK50240

DS0026CH

TIL308

MM5320

MM5330

LD110/111

MC14433P

MISCELLANEOUS

Quad Low Noise bi-let Op Amp 2.49

Switching Regulator 4.49

Single Switching Regulator 1.75

Divide 10/11 Prescafer 19.95

Hi-Speed Divide 10/11 Prescaler 11.95

Photo-Darlington Oplo-lsolator 3.95

Top Oclave Freq. Generator 17.50

5Mhz 2-phase MOS clock driver 3.75.27" red num. display w/inleg. logic chip 10.95

TV Camera Sync. Generator 14.95

4ft Digit DPM Logic Block (Special) 3.95

3ft Digit A/D Converter Set 25.00/set

3ft Digit A/D Converter 13 95

LITRONIX ISO-LIT 1

Photo Transistor Oplo-lsolator(Same as MCT 2 or 4N25)

49c eacli

SN 76477

SOUND GENERATORGenerates Complex SoundsLow Powei - Piogrammable

$3.95 eacli

TV GAME CHIP AND CRYSTAL

AY-3-8500-1 and 2.01 MHZ Crystal (Chip & Crystal T nc ,

includes score display. 6 games and selecl angles, etc 7 . 95/SBl

$8.404.404.401.551.50.39

XR205XR210XR215XR320XR-L555XR555XR556XR567CP .99XR567CT 1.25XR1310P 1.95XR1468CN 3.85XR1488 1.951.95

EXAR

JE2206KB 19,95XR1800 3.20

XA2208 5.20XR2209 1.75

XH2211XR2212

5,25.35

XR2240 3.45

XR2556XR2567XR34Q3XR4136XR4151XR4194XR4202XR4212XR455AXR4739XR4711

3.60

2.05

DIODES

VOLTS W

3.3 400m

5.1 400m5.6 400m6 2 400m6.8 400mj}.0 400m

12.0 400m

8.2 400m15 400m

5.6 500m

6.2 500m

6.8 500m

7.5 500m

12 500m

15 500m

TYPE

1N746

1N751

1N752

1N753

1N754

1N757

1N759

1N959

1N%5

1N5232

1N5234

1N5235

1N5236

1N5242

1N5245

1M456 25 40m

1M45B 150 7m

1N4B5A 180 10m

WjOOl 50 PIV 1 AMP

4/1 004(1.004/1.004/1.004/1.004/1.004/1.004/1.004/1 002828

6/1.006/1,005/1.0012/1.00

TYPE

1N40021M40031N40041N40051N4006W4O071N36001M41481N41541N47331N47341N47351N47361N47381N47421N47441M1B31N11841N11851N11861N1188

VOLTS W

100 PIV 1 AMP

200 PIV 1 AMP

400 PIV 1 AMP

600 PIV 1 AMP

800 PIV 1 AMP

1000 PIV 1 AMP

50 20Om

75 10m

35 10m

12 1w

15 |W

50 PIV 35 AMP100 PIV 35 AMP150 PIV 35 AMP200 PIV 35 AMP400 PIV 35 AMP

PRICE

12/1.0012/1.0012/1.0010(1 0010/1.0010/1 006/1.0015/1.112/1 00

C360C36M

2N2328M0A 980-1MDA 980-3

SCR AND FW BRIDGE RECTIFIERS

15A Q 400V35A ui 600V1.6Af.< 300V12A(ii 50V12A (« 200V

C106B1

MPSA05

MPSA06

TIS97

TISS8

40409

40410

40673

2N918

2N2219A

2N2221A

2N2222A

PN2222 Plastic

2N2369A

MPS2369

2N24B4

2N29Q6

2N2907

2N2925MJE29552N3053

.50

30

5/1.00

6/1.00

6/1.00

1.75

1.75

1,75

4/1.00

2/1.00

4/1.00

5/1.00

7/1.00

4/1.00

5/1.00

4/1,00

4/1.00

TRANSISTORS

FW BfllOGE REC.FW BRI0GE REC.

1.95

2N3055

MJE3055

2N3392

2N339B

PN3567

PN3568

PN3569

MPS3638A

MPS3702

2N3704

MPS3704

2N3705

MPS3705

2N3706

MPS3706

2N370?

2N371I

2N3724A

2N3725A

2N3772

2N3823

2N3903

5/1,005/1.005/1.005/1.00

2N3904 4/1,00

2N3905 4/1.00

2N3906 4/1.00

2N4013 3/1.00

2N4123 6/1,00

PN4249 4/1,00

PN4250 4/1.00

2N4400 4/1.00

2N4401 4/1.00

2N4402 4/1.00

2N4403 4/1.00

2N44Q9 5/1.00

2N5086 4/1.00

2N5087 4/1.00

2N5088 4/1.00

2N50B9 4/1,00

2N5129 5/1.00

PN5134 5/1,00

PN5138 5/1.00

2N5139 5/1,00

2N5210 5/1.00

2N5449 3/1 00

2N5951 3/1.00

CAPACITOR K

10 pf22 pi47 pi

100 pi220 pf470 Pf

.001 mf.00220047ml.01ml

, 1 /35V

15/35V22/35V33/35V.47/35V.68/35V1.0/35V

.47/50V

1 0/50V

3.3/50V

4.7/25V

10/25V

10/50V

22/25V

22/50V

47/25V

47/50V

100/25V

1O0/5OV

220/25V

220/50V

470/25V

1000/16V

22Q0/16V

15 .04 03 001/ifJ5 .04 ,03 0047^F15 04 03 01/.F)5 .04 .03 ,022nF)5 .04 .03 047,iF15 .04 .035 ,1uf100 VOLT MYLAR FILM CAPACITORS022ml.047ml

CORNER

M) 10-99 100-.05 ,04 .03505 .04 035

.12

.10

.07

.1ml

22ml .33 .27

+20% 0IPPED TANTALUMS (SOLID) CAPACITORS.39 .31 .25 1-5/35V A\ .33

.39 .31 .25 2.2/35V .51 .41

.39 .31 .25 3 3/25V .53 .43

.39 .31 .25 4.7/25V .63 .51

.39 .31 .25 6.H/25V .79 .63

.39 .31 .25 tgrtfiV 1.39 1.12

.39 .31 .25 £%v .79 .63

MINIATURE ALUMINUM ELECTROLYTIC CAPACITORS

.10

.47/25V.47/50V1.0/16V1 0/25V1.0/50V4.7/16V4.7/25V4.7/50V10/16V10/25V10/S0V47/50V100/16V1D0/25VI00/50V220/16V470/25V

Radial Lead.15 .13

J/

314 BYTE May 1980

MINIATURE SCREWDRIVER

2/S1.00

MAGNETIC RETRIEVER TOOL

^a EXTENDS TO 26)4" - ROTATES 360°STRONG, LIFETIME MAGNET

MRT-2281 $3.95

Picks up elusive metal parts or toolsin hard-to-reach places.

CONTINENTAL SPECIALTIES

LOGIC PROBE KIT

SPECIFICATIONSInput Impedance: 300,000 Ohms.Thresholds: "Lo" 30%Vcc - "Hi" 70%VccMaximum Speed: 300 nsec, 1.5MHzInput Protection: i50VDC continuous 117VACfor 15 sec.

Power: 30mA <9>5V - 40mA @ 15V - 25V max.reverse voltage protected; 36" cable with colorcoded clips included.Operating Temp.: 0-50°C.Dimensions: 5.8L x LOW x 0.7D in.(147 x 25 x 18mm)Weight: 30 oz. (85 gm)LPK-1 S21.95/Kit

1111)11Kill '"

m

>m»

Proto Clips

14-PIN CLIP PC-14

16-PIN CLIP PC-16

24-PIN CLIP PC-24

40-PIN CLIP PC-40

S 4.50$ 4.75$10.00$16.00

Proto Boards

PB-6 $17.95

JS}8".\ P8-100 19.95

PB-101 22.95

TJ'l PB-102 26.95

PB-103 44.95

PB-104 55.95

PB-203 99.95

PB-203A 155.00

PB-203A-KU . . . 131.00

Jumbo 6-Digit Clock Kit

* Four .630"ht. and two .300"ht.common anode displays

* Uses MM5314 clock chip

* Switches (or hours, minutes and hold functions

* Hours easily viewable to 30 feet

* Simulated walnut case

* 115VAC operation

* 12 or 24 hour operation

* includes all components, case and wall transformer

* Size: 6V« x3Vax.1V*

JE747 $29.95

• Bright .300 ht. comm. catr

ode display

• Uses MM5314 clock chip

• Switches for hours, minuttand hold modes

• Hrs. easily viewable to 20 f■ Simulated walnut case

• 115 VAC operation

• 12 or 24 hr, operation

JE701

"Size: 6a-4" x 3-1/8" x 1?i"

6-Digit Clock Kit $19.95

Regulated Power Supply

Uses LM309K. Heat sink mprovided. PC board con- "~-struction. Provides a solid1 amp @ 5 volts. Can supply upto i5V, ±9V and ±12V withJE205 Adapter. Includes compo-nents, hardware and instructions.Size: 3V3" x 5" x 2"H

JE200

$14.95

ADAPTER BOARD-Adapts to JE200-±5V, ±9Vand+12V

DC/DC converter with +5V input. Toriodal hi-speed switching XMFR. Short circuit protection.PC board construction. Piggy-back to JE 200board. Size; 3'A" x 2" x 9/16"H

L JE205 $12.95

MICROPROCESSOR COMPONENTS

8D8QA.S0B0A SUPPORT DEVICES-

8080A CPU

8212 8-Bit Input/Output

8214 Pnorty Interrupt Comm!

8216 Bt-Drcclional Bus Oliver

B22J Clock Generator,Driver

8226 Bus Driver

8228 System Conlrolloi/Bus Driver

823B System Controller

8251 Prog. Comm 1/0 (USART)

8253 Prog Interval Timer

8255 PrDg. Perrph 1/0 fPPl)

8257 Pruo DMA Conlrol

8259 Prog Interrupl Control

BBOO/fiBOO SUPPORT DEVICES—

MC6800 MPU

MC6B02CP MPU with Clock anil Ram

MC6B10API 128XB Sialic Ham

MC6821 Perirjh Inier Adarjt (MC682DI

MC682B Priority Interrupt Controller

MC6S30L8 1024X8 Bit ROM (MC68A30-8)

MC6850 Asynchronous Comm Adapter

MC6852 Synchronous Serial Dala Adapl

MC6860 0-600 ops Digital MODEM

MC6B62 2400 Dps Modulator 14.95

MC68S0A Quad 3-State Bus Trans. (MCBT26) 2.25

MICROPROCESSOR CHIPS—MISCELLANEOUS

Z80[780C) CPU S13.95

Z80A(780-1) CPU 15.95

CDP1802 CPU 19.95

2650 MPU 19.95

6502 CPU 11.95

8035 8-Bit MPU w/clock. RAM. 1/0 lines 19.95

P8085 CPU 19.95

TMS990OJL 16-Bll MPU w/hartlware, multiply

-MICROPROCESSOR MANUALS-

M-Z80 User Manual

M-CDP1H02 User ManualM-2650 User Manual

- ROM'S

2513|2140| Character Gencr.ilw dipper case) $9.95

2513(3021} Character Genorator(lower case) 9.95

2515 Character Generator 10.95

MM5230N 2048-Bil Read Only Memory 1.95

7,49

2M1I81

1295

2114L-3

MM500H

MM503H

MM504H

MM506H

MM510H

MM5016H

2504T

2518

2522

2524

2525

2527

2528

2529

2532

3341

74LS670

SHIFT REGISTERS —

Dual 25 Sit Dynamic

Dual 50 Bit Dynamic

Dual 15 Bit Static

Dual 130 Sit Static

Dual 64 Bit Accumulator

500/512 Bit Dynamic

1024 Dynamic

Hex 32 Bit Static

Dual 132 Bit Static

512 Static

1024 Dynamic

Dual 256 Bit Sialic

Dual 250 Sialic

Dual 2*0 Bit Static

Quad 80 Bit Static

Fifo

4X4 Register file (TnState)

510i

528B/2107

7489

74S20O

93421

UPD414

(MK4027)UPD416

(MK4116)TMS4044-

■15NLTMS40452117

256X5

1024X1

25GX4

1024X1

1024X1

25GX4

256X4

1024X4

1024X4

1024X4

1024X4

256X4

4096X1

16X4

256X1

256X1

4K

S.50 MMS262

1702A

271E1NTEL

TMS2516

(27151TMS253227082716 T.l

"Re5203

6301-1(7611)6330-1(7602)B2S2382S11582S1237418674188

DynamicSialic

Sialic

Sialic

Static

Sialic MOS

Sialic 450ns

Static 450ns low power

Static 300ns

Sialic 300ns low power

Sialic

Dynamic

Static

Sialic Instate

Sialic

Dynamic 16 pin

16K Dynamic 16 pin 250ns

4K Sialic

1024X4 Sialic16.384X1 Dynamic 350ns(house marked)2KX1 Dynamic

PROM'S

2048 FAM0S

16K" EPROM

16K* EPROM

'Requires Single -5V power supply

4KXB EPROM

BK EPROM

16K" EPROM

quires 3 voltages. —5V, «-5

2048 FAMOS

1024 Tristaio Bipolar

256 Open C Bipolar

32X8 Open Collector

S5.9559.9539.95

12V

f-S-1013 30K BAUD

Bipolar

Trislale

TTL Open Collector

TTL Open Collector

Sialic

14.953.492.953.95

1995

JE600 HEXADECIMALENCODER KIT

FEATURES:

• Full S on latched output lor micro-processor use

• 3 User Delme keys with one being bi-stable ope r alio n

• Denounce circuit provided lor all 19

► LEDtt

infy ei

lies

Easy interlacing with standard 16 pin

1C connector• Only - SvDC reouired lor operationsFULL 8 BIT LATCHED OUTPUT—19 KEYBOARDThe JE600 Encoder Ke/boaiO provides two separate neiadecimaiilioils produced (ram sequential key entries lo allow direct prog-ramming lor B bil micdlprocessor nr 8 bll memory circuits Three(3) additional keys are provided tor user operations with one havinga bistable output available The outputs aie lalched and momloredwith LED readouts Also included is a key entry strobe

JE600 $59.95

Hexadecimal Keypad only S14.95

DIGITALTHERMOMETER KIT

■ s

Dual sensors—switching control for in-door/outdoor or dual monitoringContinuous LED .8" ht. displayRange: -40°F to 199°F / 40°C to 100°CAccuracy: ±1°nominalSet for Fahrenheit or Celsius reading

walnut case - AC wall adapter incl.

3-1/4,,Hx6-5/8-'Wx 1-3/8"D

JE300 $39.95

62-Key ASCII Encoded Keyboard Kit

The JE610 62-Key ASCII Encoded KeyboardKit can be interfaced into most any com-puter system. The JE610 Kit comes com-plete with an industrial grade keyboardswitch assembly (62 keys), IC's, sockets,connector, electronic components and adouble-sided printed wiring board. Thekeyboard assembly requires +5V @ 150mAand —12V @ 10mA for operation.

FEATURES:

•60 Keys generate the full 128 char-acters, upper and lower case ASCIIset

•Fully buffered

• 2 user-define keys provided forcustom applications

• Caps lock for upper case onlyalpha characters

• Utilizes a 2376 (40 pin) encoderread only memory chip

•Outputs directly compatible withTTL/DTL or MOS logic arrays

•Easy interfacing with s 16-pin dipor 18-pin edge connector

JE610 $79.95

62-Key Keyboard only. .$34.95

HICKOK

LX303 Portable LCD Digital Multimeter

LX303 Digital Multimeter $74.95

RC.3 115V AC AD4PTEB 7.50

CC-3 PADI3ED CARRYING CASE 7.G0

VP-10 XIODC PROBE ADAPTER lUpto 1QK} 14.9S

VP-dO 40kV DC PROBE 35.00

CS-1 10 Ami> DC Current Stumi 14.95

$10.00 Min. Order — U.S. Funds Only Spec Sheets — 25*

Calif. Residents Add 6% Sales Tax 1980 Catalog Available - Send 41* stamp

Postage — Add 5% plusS1 Insurance (if desired)

r^^t^W 1^'S?^^?'^ PHONE

V f^ftO r ISmPCO ORDERS

J 1--°" -" _ I gj ! ISSS5£ WELCOME

;. ci^jji' ^JBBaujEu^a (415)592-8097

MAIL ORDER ELECTRONICS - WORLDWIDE1355 SHOREWAY ROAD, BELMONT, CA 940025-80 PRICES SUBJECT TO CHANGE

The Incredible"Pennywhistle 103'

$139.95

Kit Only

Tha Pennywhislle 103 is capable nl recording dn!a lo led iron audio tape wftboul

critical speed requirements lor the recorder and il is able to communicate directly wild

anolliei modem and terminal lor telephone "hamming" and communications. In

addition, it Islreeolcrilical adjustments and is built wiihiDr.precis oi..'cAdi.yavaitjDlr;

parts.

Data Transmission Method ..., .Freqgency-ShiM Keying. foi:-duD'e> (hait-duplex

selectable) .

Maiimum Dala Rale 300 Baud

Dala formal Asynchronous Serial (return io mark level required

between each character}.Receive Channel Frequencies .. .2035 Hi lor space. 2225 Hz lor mark.Transmit Channel Frequencies . .Switch selectable: Low (normal! - 1070 space.

1270 mark. High 025 space. 2225 mark

Receive Sensilivity 46 dhm accoushcally coupled.

Transmit Level 15 dhm nominal Ad|ustable Irom -6 dom

lo 20 dbmReceive Frequency Tolerance .. .Frequency relerence aulomalically adjusts to

allow lor operation between 1800 Hz and 2400 HiDigital Oala Interface Ell RS-232C or 20 mA current loop (receiver is

op to 1 sol a led and non-polar)

Power Requirements 120 VAC, single phase, 10 Walls.

Physical All components mount on a single 5' by 9"

printed circuit board All components included.Requires a VQM. Audio Oscillator. Frequency Cbunier and/or Oscilloscope to align

TRS-8016K Conversion Kit

Expand your 4K TRS-80 System to 16K.Kit comes complete with:

* 8 each UPD416-1 (16K Dynamic Rams ) 250NS

* Documentation for conversion

TRS-16K $75.00

■30 AWG wire *.025" square posts■ Daisy chain or 'Built-in cut off

point-to-point • Includes 50 ft. wire• No stripping or slitting required'

just wrap

W.r.

Part No.JW1-B

Color

Blue

Prica

S14.9S

JlrV-IW

While

14.95

JW-l-Y

Yellow

14.95

JiY-1-R

Red

14.95

JUST bVRAP' Replacement Wire

Part No. Color Prica

R-JW-B Blue 50 ft. roll $2.98

RJW-W White 50 It. roil 2.98

R-JW-Y Yellow 50 It. roll 2.98

R-JW-R Red 50 ft. roll 2.98

JUST WRAP" Unwrap Tool $3.49

based light-duty;mall componentsd assemblies. ABS con-ruction. 114" jaws, 1%"travel.Can be permanently

VV-1 $3.49

ADJUSTABLE WRENCH

•Two Sizes: 6" and 10"•Professional Quality•Chrome Vanadium Steel

6"-AW-6 . . $4.95 10"- AW-10..$6.95

JOYSTICKVIDEO CONTROLLER

Or

i

• IDEAL FOR ALL VIDEO GAMES OR REMOTE CON-TROL PROJECTS

• SMALL CASE SIZE: 1-1/2"H X 2-3/8"W X 4-5/16"L•2 MINIATURE POTENTIOMETERS-40K OHM EACH

• SPST PUSH BUTTON CONTROL

a 5-WIRE CONNECTION CABLE - 5 FEET LONGa RUGGED PLASTIC CASE

JVC-40 $4.95eachy

Circle 274 on inquiry card.

BYTE May 1980 315

Word Processingfor UCSD Pascal

PROFF formats and prints out texttiles. FORML interacts with PROFF toproduce multiple copies of a form let-ter, each with a different addressee.Features include:

-multi file input— interactive debug—adjustable margins—filling, centering—underscoring

Each program is written in UCSDPascal and is distributed on floppydisk. User manuals are included orcan be purchased separately. Volumediscounts are available.

(714)452-0681

Renaissance Systems Inc.

11760 Sorrento Valley Rd.

San Diego, Ca. 92121

16 K RAMS & RAM CONTROLLERS

16KX1 DYNAMIC RAMS MMittra

• 200 NSEC ACCESS/375 MSEC CYCLE TIMES

• 16 PIN/TTL COMPATIBLE

• ALL CHIPS BURNED IN AND FULLY TESTED

• PRICE WITH DATA SHEET

$68.00 IN OTY OF B/THAfS SB 50 EACH

6800/6502 64K BYTE RAM 8 CONTROLLER SETMAKE 6« BYTE MEMORY FOB YOUR 6800 OR 650?THIS SET INCLUDES:

• 32 M5K 4116-3. 16K X 1. 200 NSEC RAMS■ 1 MC3480 MEMORY CONTROLLER

• 1 MC3242A MEMORY ADDRESS MULTIPLEXERAND COUNTER

• OATA & APPLICATION SHEETS PARTS TESTEDAND GUARANTEED.

S295.00 PEB SET

DYNAMIC MEMORY CONTHOLLFR mcmw

• GENERATES BAS/CAS S BEFBESH TIMING FOR16K T0 64K BYTE MEMOBIES

. PBICE WITH DATE SHEET: S13 95 EACH

MEMORY ADDRESS MUX/COUNTER mojcap. MUX ADDBESS & REFRESH COUNTER FOB 16K TO64K BYTE MEMORIES

• PRICE WITH DATA SHEET S1250 EACH

QUANTITY DISCOUNTS AVAILABLEAll OHIHRS P0S1PAIO US IIENEIS (IV INUHNAtm'M!0RDEE1S CHECK OR MONEY IIHOEE! VI5A.BA.MC A!SO ACCEPTEO SEW ACC1 NO, EXPIRATION OAK MNIlnHflNKNfJ WITH SIGNED 0EIOEH Cfllll HESIIllNIS I'lUSl ADO(:■. SALES TAX PHONE QITDEFES [7141 b.13 4460

MEASUREMENT SYSTEMS & CONTROLS. i»c

MEMORY OEVICES DIVISION

BET NORTH MAIN SI ORANGE CA 97RBB

DISK DMV€/CftT•S(1L€*^

Shugart

SR801R

for

RS MOD. II

ONLV

*489 «■

Hazeltine 1OOO (unused) ! 599

Shugart SH400 282

Pertec FD200 s282 - FD250 ... 399

MPIS51 S279-S52 399

SA801Rw/PS/Cab 799

Dual Drives Lu/PS/Cab 1645

LIMITED QUflNITITeS

MTI

3304 W. Mocflrthur Blvd.Santo fina, CFI 92704

(714) 979-9923

Circle 275 on inquiry card.

Circle 277 on inquiry card.

TERMINAL

DATA

CORPORATION

MODEL 1200 RS 232 DATA SPLITTER

available in kit form

Model 1200K gives the terminal or micro-processor user a second interface (or 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 $64.00

write or call

TERMINAL DATA CORP.

11878 Coakley Cir.

Rockville, MD 20852

{301} 881 7655

MYCHESS

•Highest scoring microcomputer

chess program at the 1979 ACM

North America Computer Chess

Championship.•Available for CP/M. CDOS. IMDOS,

TRS-8C hard-sectored North Star

with CP/M

•Program allows 9 levels of play•Searches on the opponent's time•Program enables you to save game

for later play•Optional formated hard copy of

game• Allows computer to play itself

$50.00

Contact:

COMPUTER SEHUJCES

2431 Lyvona LaneAnchorage, AK 99502(907) 243-8730

Floppys &Systems Repair

DRIVES

• Per Sci - Shugart

• Pertec - Micropolis

COMPUTERS

• Apple - TRS-80

Computer Service Center

1023 N. La Brea

Hollywood, CA 90038

(213) 851-2226

Circle 278 on inquiry card.

Circle 279 on inquiry card.

Circle 280 on inquiry card.

SURPLUS ELECTRONICS

ASCII

[tear

ASCII

IBM SELECTRIC

BASED I/O TERMINAL

WITH ASCII CONVERSION

INSTALLED $645.00

• Tape Drives • Cable

• Cassette Drives ■ Wire

• Power Supplies 12V1 5A, 12V25A,5V35A Others, • Displays

• Cabinets • XFMRS • HeatSinks • Printers • Components

Many other items, SEND S 1.00 FOR CATALOGREFUNDABLE FIRST ORDERWORLDWIDE ELECT, INC.130 Northeastern Blvd.Nashua. NH 03060

Phone orders accepted using

VISA or MC

Call 603-889-7661

MAGTC WAND

Word Processing System

$400

Starburst ComputerGroup, Inc.

Route 2 Box 183Afton Virginia 22920

(Authorized Dealer)Magic Wand works on any CP/M'-'system with all major CRT's. Askfor our free point-by-point com-parison of Magic Wand and twopopular word processing systems.Magic Wand is a Trademark ofSmall Business Applications Inc."CP/M is a registered Trademarkof Digital Research"

(804) 361-1 180

H9 OWNCRS!

Upgrade your video terminol uuith oneof these long overdue kits:

GRRFIX —Graphical display capa-bilities assembled and tested $69.95.Kit $59.95.

CURSOR CONTROL - r totoi of8 functions assembled and tested$34.95. Kit $29.95.

FLICK€R FR€€ — 4800 baudoperation assembled and tested$79.95. Kit $69.95. ■

Fill hove a full 6 month warranty.

NORTHWCST COMPUTCR

S€RVIC€S, INC.

8503 N.€. 30th Avenue

Vancouver, UIR 98665

Circle 281 on inquiry card.

Circle 282 on inquiry card.

Circle 283 on inquiry card.

\

M

— Structured Systems

Software220 V/50 Hz available

— Dealer Inquiries Invited- Quantity pricing available

- Call for exact p&d on options

Terminal with special functionand line insert/delete keys

8 channel S 10 with real time clockand interrupt controlAutotype — powerful word processor

Qume S/5 45 RO Printer with Tractor

Feed- 10 & 20 MBY Removable Hard Disk,

DMA Controller & Custom Cabinetryavailable— CP/M is a registered trademark of DigitalResearch

In California: 415-321-5601Outside Ca.: 800-227-8266

Electrolabs

POB 6721, Stanford, Ca. 94305

Circle 284 on Inquiry card.

Worldwide:

TLX: 345567 Electrolabs PLA

PRIORITY ONE ELECTRONICS

LOBO 8" DISK DRIVE CABINET

New from Lobo, a dual Cabinet with power supply,and internal data cable hook-up.

• Cabinet accepts 2 801R, 800R, FD120, or FD200style disk drives.

• Power Supply for 2 drives.

• Assembled, tested and guaranteed by Lobo Drives.

• Shipping Weight 30 lbs.

LBO — DUAL 8 PCS $329.00

BUY CABINET AND DRIVES AND SAVE

WITH 1 DRIVELBO-801R-1PSC '775°°

WITH 2 DRIVESLBO-801R-2PSC .... '1250™

DISC DRIVE ONLYSHU-801R $499.00

EXTERNAL DATA CABLES

CARDEDGETOCARDEDGE CARDEDGE TO SOCKET

PRI-50CE-CE '19.95 PRI-50CE-SKT '19.95

10 SALE

Box of 10 Diskettes with thePurchase of a V-80 System

23%

The VISTA V-80Disk Drive System

more storage capacity thanTRS-80 • 120 day warranty • 40 trackpatch at NO CHARGE from VISTA

Single drive system $395.00

Two drive system $770.00

Four drive system $1450.00

Two drive cable $29.95

Four drive cable $39.95

Two Drive Systems comesComplete with Data Cable

NEW MS-230 DUAL TRACEIMINISCOPE 30 MHzBANDWIDTH

1 NLSMS-230 30 MHZ Scope.. $598.15

2 NLS 41-141 10 to 1 Combo Probe$54.001 NLS 41-180 Deluxe Leather Case$45.00

LIST PRICE $697.15

MS 230 COMBO PRICE $547.15

SAVE $150.00

MEMORY MEMORY

2102LIPC

Low Power 450ns in lots of 20 $1.10

2102AL-2

Low Power 250ns in lots of 20 $1.25

2114-3L

1Kx4 300ns Low Power 8/$50.00

5257-3L

4Kx1 300ns Low Power 8/$55.00

2708

8K 450ns EPROM 8/$60.00-$8.50 ea.

2716

16K 5 Volt only EPROM

8/S248.00 $32.00 ea.

CENTRONICS

730 - 1 Dot Matrix PrinterList - $995.00. ..Sale - $795.00SAVE $200.00

NOVATION CAT

ACOUSTIC COUPLER/MODEM$199.00 . Sale $156.00

'CALIFORNIA

Computer Systems

• S-100 compatible • Industrial/commer-cial quality construction • Flip-top cover

• Excellent cooling capability • 12 slotcapability (uses model 2501A) • Input105, 115, or 125 VAC • Output + 8VDC20A, + -16 VDC 4A • Active ter-mination of all bus lines • Fan and cir-cuit breaker included • Rugged con-struction

CCS-2200A Assembled & Tested

35 lbs $399.95

CCS-2200AK Kit 35 lbs $349.95

CCS-M-XVI-M

The true 16K Static Ram module forS-100 bus systems. ASSEMBLED &TESTED -100% BURN IN - FEATURES: •Fully static • Uses popular 2114 staticRAMS • +5 volt operation only • BankSelect available by bank port and bankbyte • Phantom Line capability • Ad-dressable in 4K blocks • 4K blocks canbe addressed anywhere with in 64K in 4kincrements. • Meets IEEE proposedS-100 signal standards • LED indicatorsfor board selection and bank selection •FR-4 EPOXY PC boards • Solder maskedon both sides • Silk screen of partnumber and part designator.

OUR PRICECCS-2016BA 450ns

100% Tested for 4MHZZ80 Operation

Reg. Price $349.95 $279.95

CCS-2016BB 300ns

Reg. Price ■ $389.95 $309.00

CCS-2016BY Bare Board - only. . $29.95

Aferbatim

Pirl No.

Sectoring

Applicalion

Pk. of 2

Box of IQ

VRB-M0 5Z50I

Soil SeelQi

TRS-BO Apple

S B.95

S29.95

VRB-MD525-1D

Hare] 10 Stctoi

North Slai

S 8.95

S29.95

UUBMu 525-16

Hard 16 SflCtOI

Miciopohs

J 8.95

129.95

vBB-fD3MO0O

Haid Sectoi

SIMM] All BO If)

SI 1.95

S37.00

URB-FD34-I000

Soil Sector

IBM 3740

111.95

S37.O0

SHIPPING WEIGHT 1 LB

BE SURE TO ORDER YOUR KASSETTE/10LIBRARY CASE BELOW

KASETTE/10LIBRARY

BUCK B" OlSKtTTE

SLUE HOLDER S4.50

ijirjii or :f/sio.oo

GREYBLACKBLUE

BEIGE

5'."DISKETTEHOLDER S4.25

or 3/S 10.00

fSSiSD EXPANDORAM

fesssllffil EXPANDABLE TO 64K

fe-^feaS USING 4116 RAMS

SDS-EXPANDORAM-16K KIT

List • $385.00 Sale - $205.00

SDS-EXPANDORAM-32K KIT

List - $550.00 Sale - $269.00

SDS-EXPANDORAM-48K KIT

List • $715.00 Sale ■ $330.00

SDS-EXPANDORAM-64K KIT

List ■ $880.00 Sale - $390.00

PROM-100

PROGRAMS 2708, 2716, 2732,2758, 2516 EPROMSSDS-PROM-100 KITList - $200.00 Sale - $175.95

Z-80STARTER KIT

COMPLETE Z-80 MICROCOMPUTERSDS-Z80 STARTER KITList - $340.00 Sale - $239.00

TRS-80/APPLE

MEMORY EXPANSION KITSfrom Leading Manufacturers (16K x 1200/250ns) 4116's RAMS... .8 for $55.00Add $3.00 for programming jumpers forTRS 80 Keyboard.

VERSAFLOPPY

SINGLE DENSITY DISC CONTROLLERSDSVERSAFLOPPY KITList • $250.00 Sale $235.00

VDB-8024

80 x 24 I/O MAPPED VIDEO

BOARD SDS-VDB-8024 KIT

$375.00 Sale-$315.00

iVERSAFLOPPY II

DOUBLE DENSITY DISK CONTROLLERSDSVERSAFLOPPY II KITList - $350.00 Sale - $299.00

List

EXPANDORAM II

4 MHz RAM BOARDEXPANDABLE TO 256KSDS-EXPANDORAM-II - 16K KIT

List • $470.00 Sale • $280.00

SDS-EXPANDORAM-II - 32K Kit

List 720.00 Sale - $360.00

SDS-EXPANDORAM-II • 48K KIT

List $970.00 Sale - $440.00

SDS-EXPANDORAM-II • 64K KIT

List $1220.00 Sale - $510.00

PRIORITY ONE ELECTRONICS

16723K Roscoe Blvd. Sepulveda, CA 91343

Terms: Visa, MC, BAC, Check, Money Order, U.S. Funds Only. CA residents add 6% sales tax,Minimum order $10.00 Prepaid U.S. orders less than $75.00 Include 5% shipping and handling.MINIMUM $2.50. Excess refunded. Just in case ... please include your phone no. Prices subject tochange without notice. We will do our best to maintain prices thru MAY 1980."SOCKET and CONNECTOR prices based on GOLD, not exceeding $500 per oz.

'Sale Prices are for prepaid orders only credit card orders will be charged appropriate freight

SBC-100/200

2 OR 4 MHz SINGLE BOARD COMPUTERSDS-SBC-100 2MHZ KIT

List-$295.00 Sale-$235.00

SDS-SBC-200 4MHZ KIT

List-$320.00 Sale-$255.00

ROCKWELLfiSPJ AIM-65

The Rockwell AIM 65 with 4K

RCK-AIM65 4K 8 lbs $445.00

The Rockwell AIM 65 with 1K

RCK-AIM65 1K 8lbs $375.00

4K Assembled-- RCK-AIM65-010 . $85.008K Basic in ROM RCK-AIM65-020$100.00

FOR MORE INFORMATION SEEOUR 52 PAGE AD In JANUARYBYTE OR SEND $1.00 FORCATALOG

• Sale Prices are for prepaidorders only • Quantities arelimited, subject to prior sale •CREDIT CARD ORDERS WILL BECHARGED APPROPRIATEFREIGHT ^

ORDER TOLL FREE (800) 423-5633

PRIORITY ONE ELECTRONICS

Texas Instruments

FACE GRIP LOW PROFILE

SOLDER TAIL DIP SOCKETS

C85 SERIES

VEnHTTEJi

• Face grip design provides maximum retentionforce

•Anli-wicking feature•Redundant contact points

PARTNO.

PINS

1-9

PRICE10-49

TIS-OBLP

TIS-14LPTIS-16LPTIS-18LPTIS-20LPTIS-22LPTIS-24LPTIS-28LPTIS-40LP

1410182022242840

N/AN/AN/A.30.30.35.40.45.50

.15.18.20.25.25.30.35.40.45

.10.15.18.22.23.25.30.35.42

.08

.07

.06

.14

.12

.11

.16

.13

.12

.18

.15

.13

.20

.17

.145

.22

.19

.17

.24

.20

.18

.28

.24

.21

.40

.35

.31

'MINIMUM ORDER $1.00 Per Line item

Sockets purchased in multiples of 100 per type may be combined for best price

DIP PLUGS

PARTNO.

PINS

PRICE1-9 10-24

25-99

100-249

KNX-08DPKNX-140PKNX-16DPKNX-24DPKNX-40DP

8

14162440

.50

.65

.70

1.15

1.90

.45.60.65

1.05

1.70

.43.58.62.90

1.60

.40.55.58.951.SQ.

GOLD 3 LEVELWIRE WRAP SOCKETS

AND OTHER LEADING MANUFACTURES

IES GOLD 3 LEVEL WIRE WRAP SOCKETS•Deep Chamfered ClosedEntry Contacts

•RN Side Wipe Contact Design•Terminal Barbs AllowSelf-lock into PC Board

•Rugged Socket Body Design

PARTNO.

PHTCF

1-9 10-24 25-99

RNS-08WWGRNS-14WWGRNS-16WWGHNS-18WWGRNS-20WWGRNS-22WWGRNS-24WWGRNS-28WWGRNS-40WWG

14

16182022

242840

.50

.60

.65

.85

1.00

1.25

1.25

1.60

1.85

.42

.49.52

.75.901.151.151.501.65

.40

.47

.50

.70

.80

1.10

1.10

1.40

1.55

.37.45

.47.65.751.051.051.301.45

.33.42

.44.60.701.001.001.201.35

'Price based on gold not exceeding $500 per oz.

Sockets purchased in multiples of 50 per type may be combined for best price.

ZERO INSERTIONFORCE TEST SOCKETS

dl

ZIP-16DIP $5.50ZIP-24DIP $7.50ZIP-40DIP $10.25

Texas Instruments

Standard But Not Ordinary

The HA Series standard edgeboard con-nectors ofler the best value in the edgeboardmarket today.

To assure reliable electrical connections, ouicantilever contacts are pre-loaded for optimumnormal lorce and bifurcated for redundancy:each contact point features from 50 (WireWrap') to 75 (solder tail) microinches (mini-mum) ol wrought gold inlay over a nickel dif-lusion barrier. The inlay is metallurgicallybonded to a copper-nickel-tin alloy (CA 725)

that is suited to both soldered and wire wrappedterminations. The dielectric contact-housing ismade of glass-filled thermoplastic polyester,meeting U.L. Flammability Classilication94V-0

FEATURES

RELIABLE. COST-EFFICIENT CONTACT DESIGN

• 50 (Wire Wrap) to 75 (solder tail) microinchesgold inlay over a nickel diffusion barrier(minimum thickness).

• Copper-nickel-tin CA 725 Alloy.

• Bifurcated contact points.

• Preloaded, cantilever spring design

• Contacts are user removable.

Gold Plated Edgeboard Connectors

RUGGED BODY

• Glass-filled thermoplastic polyester —Meets U.L. Flammability Classification 94V-0.— Resists common cleaning solvents

• Solder standoff — Facilitates cleaning —Reduces solder wicking

• Between contact polarization key (snaplockfor .100" & .125" centers).

• Generous chamfered card slot

• Molded contact idenlilicalion — Alpha-numeric (.156' centers) — Numeric (.100" &

125" centers).

• Location ridges (bottom) and raised dots(lop] mark every filth contact position.

• Entire connector design is U.L. Approved.

ABBREVIATIONS:STG — Solder Tail GoldWWG-Wire Wrap Gold

£1

Tl EDGE CONNECTORS

J" Contact Centers STG ■ Soldertail GOLD: WWG - Wire Wrap GOIO

.125" Contact Centers: STG - Solderlail GOLO: WWG - Wire Wrap GOLD

PART NO.

1-9

PRICE1024 25-99

PRICE10-24 25-99

100 249

TICI530-1 STGTIC-1530-t WWGTICI836I STGTIC 11)36 1 WWGTIC-2244-l STGTIC2244-I WWGTIC-25501 STGTIC-25501 WWGTIC-3060-1 STGTIC-3060-l WWGTIC-3672-l STGTIC-3672-l WWGTIC-40B0-I STGIIC -10801 WWGTIC-4386-l STGTIC-4386-1 WWGTIC-50I00I STGTIC-50ID0I WWG

1.601.702.002.102.252.402.502.702.953.203.303.903.604.403.904.654.505.40

1.451.55I.BO1.902.002.152.252.452.602.852.953.503.254.003.504.154.054.90

1.301.351.601.651.751.902.002.152.302.552.603.102.853.603.103.703.604.30

t.10

1.151.401.451.50

1.902.202.302.602.403.002.603103.003.60

1.50

1.75

1.85

2.15

1.95

2.25

2.05

2.35

2.30

2.68

2.55

2.95

2.80

3.20

2.20

S-100, VECTOR 8803, CROMENCO, IMSAI,

.250 SPACED ROWS

TIS100WWG 4.00 3.75 3.50 3.25

S-100 WIRE WRAP

TIC-2244-2 STG

2.30

2.10

185

TIC-2244-2 WWG

2.60

2.35

210

TIC-2856-2 STG

2.80

2.55

2.25

TIC-2856-2 WWG

3.20

2.90

2.55

TIC-3060-2 STG

2.90

2.60

2.30

TIC-3060-2 WWG

3.40

3.05

2.70

TIC-3I62-2STG

3.05

2.75

2.45

TIC-3162-2WWG

3.50

3.15

2.80

TIC-3672-2STG

3.45

3.10

2.75

TIC-3672-2 WWG

4.00

3.60

3.20

TICJlOBO-2 STG

3.80

3.45

3.05

TIC-4080-2 WWG

4.45

4.00

3.55

TIC-4488-2 STG

4.20

3.80

3.35

TIC-4488-2 WWG

4.85

4.35

3.90

TIS100STG

3.20

2.90

2.50

RS232 and "D" SUB-MINIATURECONNECTORS

::

b

P = Plug, Male Type - S-

'uuiinwhuiu'Socket, Female Type - C = Cover, Hood

PART NO.

DESCRIPTION

1-9

PRICE10-24

25-99

CND-DE9P

CN0-0E9S

CN0-0E9C

CND0A15P

CND-0AI5S

CN0-0AI5C

CND-DB25P

CND-DB25S

CND-DB51212-1

DB-P258C

DB1226-1A

CN00C37P

CN0-0C37S

CN0-DC37C

CND-D050P

CND-DD50S

CND-DD50C

020418-S

CND-RS232-8FT

CND-57-30360

9 Pin Male9 Pin Female9 Pin Cover15 Pin Male15 Pin Female15 Pin Cover25 Pin Male25 Pin Female

1 pc Grey Hood

2 pc Grey Hood2 pc Black Hood37 Pin Male

37 Pin Female37 Pin Cover50 Pin Male50 Pin Female50 Pin CoverHardware Set 2 pr.

1.702.351.502.453.351.602.903.751.501.451.904.406.202.255.759.652.401.00

1.502.101.352.253.201.452.703.651.301.251.654.205.952.005.458.852.20.80

1.402.001.202.103.001.302.503.351.101.001.453.905.701.755.008.252.00.70

RS232. 0B25P. EIAclass I cable6 con. 8 ft. longCenlronics 700Series printerconnector

18.00 16.00 14.00

ORDER TOLL FREE

1-800-423-5633

except CA., AK., HI., CALL

(213) 894-8171

Price$29.50

Plugboards

VCT8800V

U niversal M icrocomputer/processorplugboard, use with S-100 bus.Complete with heat sink & hard-ware, 5.3" x 10" x 1/I6"

1-4 5-9 10-24

$21.81 $19.82 $17.82

VCT8801-1Same as 8800V except plain, lesspower buses & heat sink

1-4 5-9 10-24

$17.08 $15.65 $14.04

VCT3682 9.6"x4.5"

$13.78

VCT36B2-2 6.5"x4.5"

$10.74

Hi-Density uualln-LinePlugboard for Wire Wrapwith Power & Grd BusEpoxy Glass 1/:6" 44pin con spaced .156

VCT3677 9.6"x4.5"

$11.71

VCT3677-2 6.5"x4.5"

$10.55

Gen. Purpose D.I PBoards with Bus Patternfor Solder or Wire WrapEpoxy Glass 1/16" 44pin con spaced 156

VCT3662 6.5"x4.5"

$9.88

VCT3662-2 9.6"x4.5"

$12.26

P pattern plugboards torIC s Epoxy Glass 1/16"44 pin con spaced .156

VCT3690-12CARD EXTENDER

Card Extender has too con-tacts 50 per side on .125cenlers-Attached connector iscompatible with S-100 Bus

Systems $27.69

VCT3690 6.5"22/44 pin....156 ctrs.Extenders. $13.98.,

Circle 285 on inquiry card.

ORDER TOLL FREE (800) 4235633

■ Animation Compilier andGraphics Editor Package

■ Add smooth, fast actionto basic programs

■ Create ad layouts,newsletter covers, posters

$14.95

~ ■ w w Write or call lor complete catalog

AMCROTPONICSJnc.

1125 N. Golden State Blvd. / Suite GTurlock. CA 95380 (A)(209)667-2888/634-8888

IVe are experiencing telephone difficulties,

please keep trying.

Catilotma residents ,toi)6°n ia> visa or MC

BASEX is . . .

• More Basic than BASIC!

• More Forthright than FORTH!

• More Tiny than TINY C!

• Runs Fast like FORTRAN!

• Less Hascal than PASCAL!

*97 page manual ($8) with complete

source listing.

•TAPES ($25) - Meca, SOL, PolyBB,

TRS80 (16K/II), Paper tape.

•DISKS — NStar ($25); CPM ($35) 8"

SD or 5" (NStar, Meca, Micropll).

ADD $.75 shipping ($1.50 UPS orspecial handling)

^w

^

■Ffl"lUjI

INTERACTIVE MICROWARE, INC

Box 771, State College, PA, 16801

CALL (814) 238-8294

6800/6809 PASCAL

DYNASOFT PASCAL is a cassette basedPASCAL subset designed to run on most 6800/6809 systems with 12K or more of memory.

DYNASOFT PASCAL includes most ofthe control structures of standard PASCALincluding IF THEN-ELSE, CASE-OFOTHERWISE, WHILEDO, REPEAT-UNTIL, FORTO/DOWNTO DO, and recursive PROCED-URE'S and FUNCTION'S. It supports the datatypes INTEGER, CHAR, BOOLEAN, scalar(user-defined), subrange, pointer and ARRAY.It is built around a one pass compiler whichproduces fast, compact p-code and comescomplete with a line-oriented text editor, p-codeinterpreter, and program SAVE and LOADroutines. The whole system resides in less than8K.

The cassette version with manual is priced at$35 plus $3 for postage and handling. Pleasespecify 6800 or 6809.

mt

systems

P. O. BOX 51

WINDSOR JCT..N.S.

CANADA BON 2V0

Circle 286 on inquiry card.

Circle 287 on inquiry card.

Circle 288 on inquiry card.

/ Scotch

Floppy Discs

Lowest prices. WE WILL NOTBE UNDERSOLD!! Buy any

quantity 1-1000. Visa Masterchargeaccepted. Call free (800)235-4137for prices and information. Allorders sent postage paid.

PACIFICEXCHANGES

100 Foothill BlvdSan Luis Obispo. CA93401 (In Cal call(805)543-1037)

USERS!

Read

PEEK ICSI

The Unofficial OSI Users Journal

-User Equipment Reviews-Hardware Mods

-Software Exchange•Peeks & Pokes

-Bugs & Fixes

Send $8°° for 12 issues to:

PEEK (65]

62 Southgate Ave.Annapolis, MD 21401

AURORA, IL. AREA

lppkz computer

Sales and Service

&8h

»«**"'

4\\<^e

IDS-440-G PAPER TIGERPRINTER '995°°

FARNSWORTHCOMPUTER CENTER

1891 N. Farnsworth Ave.Aurora, II. 60505Ph. 312-851-3888

Circle 289 on inquiry card.

Circle 290 on inquiry card.

Circle 291 on inquiry card.

INDUSTRIAL MICRO SYSTEMS COMPUTER

Desk Top Model With Z80 CPU at 4 MHZ • DualDouble Density 8inch Shugart Floppy with 1.2 MBytes • 48K Memory with Bank Switching andexpandable to 256 K • 2 Serial and 3 ParallelPorts • Transparent Single and Double DensityOperation • CPM 1.4 Disk Operating System(Optional) • 90 Days Parts and Labor Warranty

• Complete and Ready to Run at $4,250.00

Or a Complete System Including CRT Terminal

and Texas Instrument 820 Printer at . . . $7,350.00

Dealer Inquires Invited.

SOO NAM KIM

O S M COMPUTER23E4 WALSH AVE.. SANTA CLARA. CA 95051 (408) 496-6910

COMPUCOLOR IIBACKGAMMON

Impressive graphicsPlayer vs. Computer* 16K RAM requireddiskette $18.00

Blank CCII diskette$4.50

Same day shipping with

money order or send check

to . . .

Med Ford Software

419 N. Chapelgate Ln.

Balto., Md. 21229

Dealer inquiries invited

THE COMPUTER SHOP, INC.Th(

1000 Pike Road \J ,

Birmingham, AL 35218 ^(/nmmil> . Ill((205)781-0711 "V g* - r

SCOTCH 3M BRAND DISKETTES 9S* I

Type Size Density Package Sector Price/10 Apl.

744-0 5 Vi" single storage case soft 36.00 (1)

744-0 5 W single library case soft 39.00 (1)

740-0 8" single storage case soft 36.00 (2)

741-0 8" double storage case soft 55.00 (3)

(1) for Apple, TRS-80, Pet, SWTP. Cromenco

(2) for IBM 3740 series and compatible drives

(3) for TRS-B0 Mod II, Shugart 800/801 and compatible drives

PERSONAL COMPUTING CASSETTES w/leader 10 mln$1.95, 30 mln $2.30 (10 minimum order)

OTHER SCOTCH BRAND PRODUCTS — Velostal Anti-static Mats, Digital Cassettes, Oata Cartridges, Wordprocessing supplies etc. Call or write for pricing.ANADEX DP8000 PRINTER - 9x7; Upper & lower case;Bdj. width tractor feed; bidirectional; 1K buffer; expandedprint; Parallel. RS232C serial, and Current loop Interface.Many more features. $949. Send $2 P & H for a sampleprintout. (Call or write about the new 9500/9501).

LOBO Minidisk Drive for TRS-80 — $395

Authorized SCOTCH Minicomputer DistributorAll merchandise Is premium grade. Alabama residents add6%. Foreign orders add 10%. Orders accompanied bypayment are shipped at our expense.

Circle 292 on inquiry card.

Circle 293 on inquiry card.

Circle 294 on inquiry card.

IS READY

Call For

DEALER

In Your Area

Z-80 CPU

Two serial ports, three par-allel ports. 2/4 MHz, onboard Prom Monitor Phan-toms. (Less cable and Mon-itor). A & T $325.00

DOUBLE/SINGLEDISK CONTROLLER

FLOPPYS

8" Shugart $550.00

8" Siemans $525.00

5" Siemans $350.00

(Double Sided)

8" CDC $675.00

8" Remex $645.00

FLOPPY DISKS

D YS AN Quality

Two stage phase lock loopcircuitry for greatest relia-bility, data transfer at maxi-mum rate. Transparent den-sity selection. 8" or 5" op-eration 2 or 4 MHZ (Somerestrictions on DMA).DMA — $425.00STD. — $385.00

16K,32KSTATIC RAM

ili§i§iP§

S^-K#-#«SM»I*

32K, 48K, 64KDYNAMIC RAM

TELEVIDEO 912

80 x 24—Lower case des-cenders. Teletype or type-writer keyboard 110/220VAC. 50 to 19.2K BaudHex entry pad. Similar to50ROC but better lookingwith NO FAN NOISE

Worlds most reliable mem-ory, responds to extendedaddress lines A16, A17,cool running, fast.16K-$395.00 32K-$650.00

TELEVIDEO 920

32K, 48K, 64KERROR DETECTING

Cromenco/ Alfa Micro

Basic dynamic board testedto run at 4MH2 with ourZ-80 board. 4116 chips at200 nanosecond speed in-sures most reliable datasto-rage. Double density andDMA compatible.32K-$580.00 48K-$640.0064K-$750.00

WINCHESTER/SHUGARTSA 1000

Similar to TV 912 but hasprogrammable functionskeys across top. Excellentfor WORDSTAR Text Edi-ting.

State of the art develop-ment. Parity generation anderror detection. Compatiblewith 16 bit CPU designs.16K bank, select under soft-ware control. 4MHZ Z-80,8086, Cromenco, Alpha Mi-cro compatible.32K-$650.00 48K$725.0064K-S850.00

WINCHESTER/CENTURYDATA SYSTEM(Hunter Shown)

5 megs now expandable to10, works alongside floppydisk drive for expandedstorage. Use with controllerbelow.

$1950.00

20 megs expandable to40—Marksman series, plugsinto our CPU parallel portor MP/M board drive, cabi-net, power supply, 2.0 Bios.$4850.00

MPM®l/0 TIMER

80 X 24 VIDEO

8" SSSD $4.25

8" SSDD $5.50

8" DSDD $7.60

5" SSDD $4.10

(Boxes of 10 only)

AvailableMarch 1980

Designed for MP/M® soft-ware of Digital Research. 6users serial port, three 8 bitparallel ports for hard disk.Timer and vectored in-terrupt.

®TM Digital Research

WINCHESTER/FLOPPYINTERFACE

SOFTWARE/CABLES/PROMS

AvailableMarch 1980

_r

®

CP/M 2.2.

Keyboard input, Z—80 Pro-cessor, on board RAMmakes this a non-memorymapped substitute for aterminal when mated witha keyboard.

$430.00

Allows mixing of ShugartWinchester and floppydrives on same cable whenused with DP-DSK. Sup-plied with software Biosfor MP/M®and 2.0<8>TM Digital Research

MP/MT2708 Monitor2716 MonitorDisk 50 PinRS-232 . . .CPU to BackDisk DC . .Disk AC . .Winchester .

$150.00

$350.00

$ 25.00

40.00

22.00

15.00

32.00

4.50

2.50

28.00

DP s-ioo main Frame

• 12 slot S-100 Motherboard (6 populated)

• +8V @ 20A ±16V @ 6A. (Nylon card

guides).

• Mates with disk system shown in cen-ter column.

• 3 user convenience outlets at rear.

• Status indicators for I/O wait, memoryerror, voltage levels.

• Multi-user capable with circuit boardselection at top.

Kit (less fans) $295.00 A & T $450.00

disk Drive Storage

• Cabinet comes with multiple power.

• Supply to suit all popular disk drives±5A, +24 @ 6A.

• DP-1000K Twin double density Shu-gart SA-800B or Siemens FDD-100-8(1 megabyte). $1800.00

• DP-2000K Double sided, double den-sity Shugart SA-850-R or SiemensFDD-200-8 (2 megabytes). $2450.00

• Drive box less drives with ample powersupply.

Kit (less fans) $295.00 A & T $450.00

NORTH STAR Competitor

• Cost effective Z-80 dual drive micro!system.

• Double density Siemans drives sport |340K single sided, 680K double sided.

• 32K RAM standard, expandable to 64K.

®

• CPM 2.0 software included.

$2450.00

West:

DELTA PRODUCTS

15392 Assembly Lane, Unit AHuntington Beach, Calif. 92649Tel: (714) 898-1492

Circle 295 on inquiry card.

mm

PRODUCTS

®,®

Telex: 681-367 DELTMAR HTBH

East:

DEL TA PRODUCTS

11 Edison Drive

New Lennox, Illinois 60451

Tel: (815)485-9072

TEXAS INSTRUMENT 99/4 COMPUTER

TI 810 PRINTERCENTRDNIC PRINTERS:

730-1 PARALLEL PRINTER730-2 SERIAL PRINTER779-1 FRICTION FEED779-2 TRACTOR FEEDCOMPRINT 912 APPLE,TRS-80,PAR

912 SERIALANADEX UITH PAR X SERIAL INTERFACECOMMODORE BUSINESS MACHINES:PET 2001-8K COMPUTERPET 2001-16KPET 2001-32K

PET 2022 TRAC. FEED PRINTERPET 2023 FRIC. FEED PRINTERATARI BOO400INTERTEC SUPERBRAIN(32K>NORTH STAR COMPUTER AND ACC.

** SAVE » SAVE ♦ **DI5PLAY TERHINALS:INTERTUBE IIHA7.ELTINE MOO14101500IMMEDIATE DELIVERY FROH STOCK.

MULTI-BUSINESS COMPUTER SYSTEMS

M28 MARLBOROUGH STREETPORTLAND, CONN. 0&4BO(203) 342-2747

» 989.•1590.

« 749.« 799.« 959.•* 999.$ 559.

* 599.« 799.

$ 695.» 895.*1090.

* 699.% 679.

* 88 9.

* 495.•2495.

775.690.785.990.

Circle 296 on inquiry card.

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Circle 299 on inquiry card.

80X24 VIDEOTERM™

7X9 MATRIX DISPLAY FOR

APPLE II®

LOWER CASE W DESCENDERS i

80 columns by 24 lines with easy to read 7x9 dot matrix,upper and lower case with descenders using shift lockfeature • 1K firmware incorporates PASCALand BASICprotocalls so user is not required to enter machinelanguage programs or change PASCALS. Misc. info, orGotoxy files • Compatible with all APPLE II peripheralsso user won't need new software patches lor futuresoftware products • Crystal controlled dot clock forexcellent character stability • VIDEOTERM is the samesize as the Apple language card and power consump-tion is held to a minimum through Ihe use of CMOS andlower power devices • Character set can be user de-finable up to a maximum of 128 symbols of 8x16 dotmatrix font • Display control character mode and fourstandard display formats controlled by escape sequen-ces • Built in light pen capability • Inverse displaymode • 50/60 HZ operation • Sockets on all IC's.

PRICE:Wllhoulgrnphic EPROMS345OPTIONS: Graphics EPROM line dwg S2S

VIDEO SWITCH PLATE, inserts

In case slol to choose belween

APPLE II' and VIDEOTERM S12 jfiA ■"^™

MANUAL:$15 ** mm

VIDEX 3060 N.W. Thistle PI. Corvallls, OR 97330 Phono (503) 7604621

CROMEMCOSYSTEMS

DISCOUNTED

System 2 with 64k RAM—$3195System 3 with 64k RAM—$5735

Discounts up to 20%

on most Cromemco hardware.

We carry the full Cromemco line.

TORREY PINES BUSINESS SYSTEMS

14260 Garden Rd.. Suite IB

Poway, California 92064

(714) 486-3460

Add 3% for shipping and handlingCalifornia residents add 6% sales tax

Circle 297 on Inquiry card.

H8 Owners

»

AD-8/4HANALOG/DIGITAL SUBSYSTEM

• 8 A/D Input Channels

• Fast-Over 4500 A/D Conversions/Sec

• 4 D/A Output Channels — Each WithSample and Hold

• Full 8 Bit Resolution

• Uses Single Card Slot

• Fully Assembled And Tested

• Full Documentation Provided

• Visa, Master Charge OK

$125.00CCM, Inc.

P.O. Box 2308 Reston.Va. 22091

Circle 300 on Inquiry card.

COMPLETE

S-100MAINFRAME

$299

Sturdy aluminum enclosuremeasures 8"H x 17"W x 14"Dand includes 6 slot S-100 mother-board with connectors installed,8 V @ 14 A and ± 16 V @ 2 Apower supply, fan, card guides,circuit breaker, reset switch, linefilter and connector cutouts.

LOGICON

P. O. Box 1343

Pleasanton, CA 94566

(415) 462-7361

SUN-FLEXOPTICAL FILTER

-.JJCAL FILTER ENHANCES CONTRAST, •■:.:. 0BUU"'««! REFLECTIONS, IIHILE ALLDUIHG

UP sii.ji .;-...

Sot this uhretouchep photograph7flF,SE benefits.

BILE TO EPEILT PEHF THE COFT OHMOF THE SCFEEI,, IT'S EECilJE I! L.C'iiMURI CRT Itf VOUR HOHE OR OFFICE.

::]tf FOR fROTE::I:,G :u: EiE:< ff;- !:[:;_■""HUE I! Ul.tt FOE B v!i.:h FI[T£i. i::.fi ■:■

Um Hit I25.lt '"■ is-ikch. hi; <■:.<■:COW.

■■OVER 58,099 S3L0

HIE

SUN-FLEX COMPANY, INC.

3020 Kerner Boulevard. San Rafael, CA 94901

1415) 456-8482

Mastercharge/VISA or Check

Circle 298 on Inquiry card.

TRS-80 16K LEVEL II

Canadian Income Tax $29.95

Inventory 49.95

Accounts Receivable -. . . . 49.95

Banking 19.95

Golf 16.95

Budgeting 19.95

Recipes 19.95

• Mailed on Cassette

• Replacement Guarantee

Use Our Company to Sell Your

Programs. Send for information

on PROGRAMMERS'

PARTICIPATION PLAN.

Want to be on our mailing list?Write us today.

QUADRUS ASSOCIATES

39 Coachwood Road, Brantford,

Ontario, Canada

N3R 3R5

Circle 301 on inquiry card.

We want your

NEW PRODUCTSSELL OVERSEAS

Established European MarketingOrganization in the high technologyinstrumentation field, based inEngland and with excellent knowl-edge of the European Market, isseeking to expand its interest in theConsumer and Professional pro-ducts field by utilizing the uniquetechnological development of themicrochip revolution in the U.S.A.

We have the finance, the distribu-tion and the European Marketingexpertise and are seeking productswith sole European distributionrights. Principals only, please con-tact Brian Gould, Managing Direc-tor, Hampshire Design, BalksburyHill, Upper Clatford, Andover,Hampshire SP11 7LW, England.

Circle 302 on inquiry card.

Circle 303 on inquiry card.

Circle 304 on inquiry card.

Try to beat our prices!

TELEVIDEOTVI-912

Upper case and lower case; 15 baud rates: 75to 19,000 baud; dual intensity; 24 x 80-char.display, 12 x 10 resolution. Numeric pad.Programmable reversible video; aux. port;self-test mode; protect mode; block mode;tabbing; addressable cursor. Microprocessorcontrolled; programmable underline; line andcharacter insert/delete.

OUR PRICE ONLY $789

OTHER VIDEO TERMINALS

INTERTUBE II, List $995 . . . ONLY $799PER KIN-ELMER 550, List $997 . . . . $799

with anti-glare screen, $1027 $829

HAZELTINE 1400, List $850 $699

1410, List $900 $749

1420 $849

1500. List $1225 $989

1510, List $1395 $1089

1520, List $1650 $1389

ADDS R-20. List $995 $945

LEAR SIEGLER ADM3A, Assembled $849

SOROC 120, List $995 . . . .SPECIAL$729

IQ140, List $1495 $1249

PRINTERS

ANADEX 80-col. dot matrix. SPECIAL$749

INTEGRAL DATA IP-125 NOW ONLY $689

IP-125w/1210 option, $838 . . NOW $724

IP-225 W/1210& 1250 op., List $988 $834

IP 225 w/tractor, 1210, 1250, 1221

(2K Buffer), 1241 (graphics) NOW $899

IDS-440 Paper Tiger, List $995 $895

w/graphics op., incl. buffer. $1194 . $989

CENTRONICS

730-1 parallel interface, List $995 . . $779

779-1, Friction Feed, List $1245. . . . 949

779-2 w/Tractor, List $1350 1049

702-2 w/Tractor, VFU, List $2480 . 1995

703-2 w/Tractor, VFU, List $2975 . 2395

704-2 w/Tractor, List $2350 1995

COMPRINT 912 w/parallel interf. $559912w/serial interface, List $699 .... 589

T.I. 810 Basic Unit, List $1895 . . . . $1695810/serial & Centronics-style

parallel interface. List $1940 .... 1735810 w/full u/lc ASCI I, Vertical

Forms Control, Compressed Print . 1895

NORTH STAR HORIZON

HORIZON 1 KITS

16K, Double Density, List $1599 .. $147432K, Double Density, List $1849 ... 168432K, Quad Density, List $2049 .... 1869

HORIZON 1 ASSEMBLED & TESTED*

32K, Double Density, List $2695 .. $227932K, Quad Density, List $2995 .... 2539

HORIZON 2 KITS

16K, Double Density, List $1999 .. $182432K, Double Density, List $2249 ... 203432K, Quad Density, List $2629 .... 2359

HORIZON 2 ASSEMBLED & TESTED*

32K, Double Density, List $3095 .. $261932K, Quad Density, List $3595 ... $304948K, Double Density, List $3590 ... 303948K, Quad Density, List $4090 .... 346964K, Double Density, List $3830 ... 323964K, Quad Density, List $4330 .... 3669* Complete w/12 edge connectors, two SIOs,one PIO, and extra drive cable.

FLOPPY DISK SYSTEMS

MORROW THINKER TOYS® Discus 2D,

List $1149 OUR PRICE $979

Discus 2D, dual-drive, List $1948 $1658

Discus 2+2, A&T, List $1549 . . . . $1319Dual Discus 2+2, A&T, List $2748 . $2335

MICROMATION Megabox, double-density w/8" drives, 1-megabyte. List $2295 . $19492-megabyte, List $3095 $2629

MICROPOLIS 1041 MacroFloppy®w/enclosure (no P.S.), List $695 . . . $6251 042 MacroFloppy w/case & AC P.S. 7091053 Dual MetaFloppy®, List $1895 . 1695

VIDEO BOARDS

I/O Mapped

SD COMPUTER VDB-8024, kit, List $370 $299

Assembled, List $470 $399

XITEX SCT-100K, Kit ONLY $154.95

SCT-100A Assembled $174.95

SSM VB2 I/O, Kit, List $169 $144

Assembled & Tested, List $234 $199

Memory Mapped

VECTOR GRAPHICS Flashwriter FW2 . . . $313SSM VB1B, 16x64, Kit, List $155 $132

Assembled & Tested, List $210 $178

SSM VB3 80-Char., 4 MHz, Kit, List $399 . $339

4 MHz, A&T, List $464 $394

INTER SYSTEMS, 16x64, A&T, List 165 . $149

CONVERT YOUR SELECTRICTO A COMPUTER PRINTER!

Power supply & electronics, A&T. You makeonly a simple solenoid installation (or havethe factory do it). Manufactured by ESCON.

S-100 Interface Version,.List $496 . $445Universal Types:

Parallel — (Centronics format, for TRS-80,Sorcerer, Apple, etc.), List $575 . . $514RS232 Standard Serial, List $599 . . 534IEEE-488 (for PET), List $660 . ... 584TRS-80 Cable 25

CPU BOARDS

(assembled unless noted)NORTH STAR Z80A (ZPB-A/A), $299 $254CROMEMCO 4 MHz (ZPU-W), List $395 335

4 MHz (SCC-W), List $450 382

VECTOR GRAPHIC Z-80, List $247 . $210INTERSYSTEMS (formerly Ithaca Audio)

NEW Series 11 Z-80, 4 MHz, List $395 $349SSM CB1A 8080 CPU Board, List $219 $186

CB1A Kit, List $159 135

SSM CB2 Z-80 CPU, List $275 $234

CB2 Kit, List $210 179

DELTA Z-80, with I/O $239

SDSBC-100, List $350 $298

SBC-100 Kit, List $295 250

S8C-200, List $400 332

SBC-200 Kit, List $320 272

MEMORY BOARDS

NORTH STAR 16K Dynamic RAM Board,A&T (RAM-16-A/A), List $499 ... $42032K A&T (RAM-32/A), List $739 ... 620

CROMEMCO (16KZ-W), List $595 .. $49564KZ-W, List $1795 1485

MEASUREMENT SYSTEMS & CONTROLS

Guaranteed performance, incl. labor/parts 1 yrDM6400 64K Board w/all 64K, $795 . $659

DM4800 with 48K, List $695 589

DM3200 with 32K, List $595 509

DM1600 with 16K, List $495 429

DM0000 with no RAM, $395 349

THE DMBSERIES -

DMB6400 64K Board w/all 64K . . . $859

DMB4800 with 48K 789

DMB3200with32K 709

MORROW SuperRAM - all static, all A&T16K, 4 MHz or 2 MHz, List $349 .. $299

32K, 4 MHz, List $699 629

16K Memory Master, List $399 .... 33924 K Memory Master, List $549 .... 465

INTERSYSTEMS (formerly Ithaca Audio)8K Static 2 MHz, A&T, List $165 . . $1498K Static 4 MHz, A&T, List $195 ... 17616K Static 2 MHz, A&T, List $475 . . 42716K Static 4 MHz, A&T, List $495 . . 44564K Dynamic, List $995 895

CALIFORNIA COMPUTER16K Static, A&T, List $349.95 .... $259

FLOPPY DISKCONTROLLER BOARDS

MORROW Disk Jockey 1, A&T ($213) .$189

Disk Jockey 2D, A&T, List $479 .... 429

SD Versafloppy 1, Kit, List $250 ... $212

Versafloppy II, DD Kit, List $430 . . . 360

Versafloppy II, DD, A&T, List $350 . . 278

DELTA double density A&T ($385) . . $345

CONDUCTOR, double density A&T . . $269

INTERSYSTEMS (formerly Ithaca Audio)

FDC-2.A&T, List $495 $439

MICROMATION Doubler, DD, A&T . $399TARBELL Floppy Disk Interface, Kit . $199

double density, Kit, List $325 295

double density, A&T, List $425 .... 380

SHIPPING & INSURANCE - Add $2 for boards, $5 for Selectric converter, $7.50 for Floppy Disk Systems, $15 for Horizons. Shippedfreight collect: Cromemco Systems, Centronics, DEC, NEC, and T.I. printers. Contact us for shipping information on other terminals and printers.All prices subject to change and all offers subject to withdrawal without notice. Prices in this ad are for prepaid orders. Sligh t/y higher prices prevailfor other-than-prepaid orders, i.e., C.O.D., credit card, etc.

—WRITE FOR FREE CATALOG -

MiniMicroMart, Inc. »

1618 James Street, Syracuse NY 13203 (315) 422-4467 TWX 710-541 -0431 circle 305 on inquiry card.

FLOPPY DISK DRIVES SYSTEMS

Qume Datatrak

Double sided floppy with NO HEADACHES.

Although many think this an impossibility, JUjgH

seeing is believing, and this drive is really

something! Shugart compatible, fully ^

optioned, reliable, and rapidly becoming

the standard in double-sided diskdom.

$599. 2/$549.

Cal Disk 142M 8

Built like the proverbial tank. Single/doubledensity, write protect, much more. WithElectrolabs' special cabling, it magicallybecomes Shugart compatible.

Please ask about Cal Dis, enclosure$389. 2/$3/9and power supply package bargian.

The following 5!4" mini-floppies share most features with their 8'cousins, so without further ado. . .

Siemens FDD100-8D

All Siemens options included in this drive,which can be configured hard/soft sector,is Shugart compatible, and not prone tosome overheating problems (that otherdrives are). A highly reliable machine,with write protect, file busy indicator,and more. $499.

§>i 11->

'"■to-

Siemens FDD 100-5D $279

Cal Disk Mini $279

Qume Datatrak 5 BASF Mini mini $279

(double sided) $399 SA 400 $299

All the above mini-floppies are fully SA400 compatible.

Manuals for all drives are $10, refundable against future purchase of drives.

Also, all 8" drives can be ordered with 220 v/50 hz for worldwide use.

Moving on to the realm of floppy disk controllers . . . although we still feel that single

density is more reliable, there are many excellent double density disk controllers

available, so choose your weapons carefully.

Disk Accessories

Subtract 15% OFF any Controllerwith Purchase of 2 Drives.

Cable kits for 8" drives with 10'50 cond. flatcable, power cable, & all connectors. Assembledif desired. ONe drive 27.5Q, two 33.95, three 38.95for mini floppies (34 cond): one 24.95, two, 29.95

CP-206 Power-one power supply. Powers twodrives more than adequately, top quality. 2.8A/24V2.5A/5V, .5A/-5V. $99.

Electrolabs

POB 6721, Stanford, CA 94305

415-321-5601 800-227-8266

Telex: 345567 (Electrolab Pla)Visa MC Am. Exp.

ENCLOSURES,

SLEEVES

Double disk drive enclosure.

Enclosure alone $139.

Including power supply & fan $199.

Single disk drive enclosure. Fits all 8" disk drives,please specify make & model No. of drive to assureproper mounting hole positions. Nonmar paintavailable in blue, beige, silver, & off-while.Enclosure alone $60Including power supply & fan $109.

324 BYTE May 1980

Rackmount Mainframe MT-200. This gorgeous

beast is so appealing that it can easily function

also as stand-alone mainframe. Very modern

styling with fully actively terminated S-100 bus.

Enclosure alone $399.

With power supply & fan $499.

With 15 slot S-100 bus $699.

With two 8" single-sided disk drives $1,699.

With two 8" double sided disk drives in place

of single-sided variety $2,299.

Tarbell floppy disk controller, A & T $325Tarbell floppy disk controller, A & T $225Tarbell double density, DMA A & T $425Tarbell double density, DMA, kit $325

Delta Products double density disk controllerOperate at 2 or 4MHZ, with 8 or 5" drives $399Micromation doubler w/programmable UARTRS-232 port $495

Sorrento Valley single density for Apple $399Again, purchase price of manuals ($5) isapplicable towards future purchase price.

Media

8". . $39.95/10 single-sided/single

density8"... $55.00 single sided/double

density8". . $55.00 double sided/single

density8". . $60.00 double sided8". . specify hard or soft5V4". . $34.95 single sided5 Va". . $60.00 double sidedVerbatism, Memorex, Scotch,orequivalent name brandDiskette head cleaning kid for 534"or 8" - $28.75 includes everythingfor 1 drive for 1 yearAlignment Diskette $39For Floppy Drives

■: :■; :/' :':

EXTRA SPECIAL !!

Imsai 65K dynamic RAM III

mm

We made a special purchase of this now unavailable board, which were always notedfor their fine performance & quality. We have a limited quanity on hand, get your orders inrapidly. These come assembled and tested, with burned-in 200 Ns RAM. Kit 299

A & T $399.

Keyboard Special

SD Systems Expandoram IIDynamic RAM

\

CHERRY "PRO" Keyboard $119.00Streamlined Custom Enclosure $34.95BOTH ONLY $134.95!!!

**..; ;

Operates at 4 Mhz, expandable memory from 16K to 256 K, allows up to 8 boards on thesame bus, Z-80 based, and invisble refresh, among other things.

16K kit $295.

16K A & T $349.

32 K kit $369.

32 K A&T $419.

48K Kit $440.

48K A & T $490.

64K kit $510.

64K A & T $560.

Data Display Monitors

Used 12" Sylvania mon-itors. Composite Video,15 MHz, 120VAC. Re-built with NEWP39anti-glare tube $89.00New P4, $89.00, usedP4 $69.00U-fix model, 10/$300.00

■.-.-■■ . . :■■....■

Televideo 912c $760.

Upper/lower caseAdjustable baud rate - 80 X 24Editing capabilities — Printer portSecond page memory option

This is a VERY limited extravaganza, so please act quickly

IMewI

Televideo 920c

$860.

Same specs as above, save for special function keys,ideal for text editing and word processing

Paper Tiger

IDS MODEL 440

— 8 Software Selectable CharacterSizes

— Parallel & Serial Interface

— 98 ASCII Character set, upper& Lower case

— Forms length control

— Tractor Feed $899.Graphics option with 2K CRT

screen buffer add $199.00

Daisy Wheel Printers

"OEM STYLE" as above,will fit any case, (Bothversions serviced by quali-fied tech). Identical toabove but subtract $12.00

ELECTROLABS

! POB 6721 Stanford CA 94305;(415)321-5601 (800)227-8266!I Telex: 345567 (Electrolab Pla)

Dynamic Devices Modem

Acoustically coupled modemassembly setAsynchrous 0-300 BaudSwitchable originate or answermodes

Operates full or half duplexmode

15 minute assembly $129.- Novation Cat $179.

^r-*""

— Digicomm Coupler $189.

Qume Sprint 3\45

PRINTER (factory warr.) $1499.

POWER SUPPLY (Borschert) 349.

(Shown mounted on rear of printer)COMBINATION SPECIAL 1699.

Cases available 200.

S-100 interface card 149.

SPRINT 5/45 RO, RS 232Complete, assembled, in case, plug-in &print, hence, no muss & no fuss $2699.

EASTER ICEGG HUNT

(while sl

pply lasts)

2114 $ 5.99

2708

$ 8.50

2114-2 6.99

2716

25.00

pd411 2.50

2732

95.00

21L02

2147

12.95

450 Ns 1.05UNPRECEDENTED!!!

6502

$ 6.25

* 16K Dynamic RAM

6809

49.00

Set of 8 For: TRS-80,

6845

39.00

Apple, Exidy, Heath,

8085

13.00

etc.

1771

26.95

* Includes all parts &

1791

37.95

instructions

AY5-1013A 3.95

* 200 NS $59.

Please call for dealer or quantity pricing. Minimum order $20.00We do custom prom programming.

ESAT 200B

BILINGUAL 80x24

COMMUNICATING

TERMINAL

Scrolling, full cursor, bell, 8x8matrix, 110-1 9,200 baud, DualFront Applications. Arabic &Hebrew, Multilingual Data EntryForms Drawing, Music, & Switch-yards. $279.

Circle 306 on inquiry card.

BYTE May 1980 325

Circle 307 on inquiry card.

DIGITAL MULTIMETERS

Sinclair PDM35 Hickok LX3036950

31/2-DigitPortableDMM

Model 2800

BeckmanTECH310

$130

Portable Oscilloscopes15 MHzDual TraceTriggeredMiniscope

$36995s

15 MHz Triggered Miniscope

Model MS-15 :;-:; ; n■'• .:■ $0CQ95

30 MHz Dual TraceTriggered Miniscope

Model MS-230 R»J. $559.00*479

. Re9 Model MS-215

$435.00

Logic Probe

■ Compact circuit poweredDetects pulses as short as//sec ■ DTL/TTL/HTL/CMOScompatibility $AAQ5

ModelLP-1

RC Circuit Box

» 36 resistors (15!!to 10 Ml!) > IBcapacitors (100 pf to

022"" $/IOReg.S49.95 **<C.

includes test leads viz Model WC 412A

ChessChallenger 7|*;

- siio.oo Mo(,e| |*yyipl

MURAPHONECordlessTelephoneSystem r-

Reg. S89.95 If )\$7495 L

GTE Flip-Phone^

FunctionGenerator

Model 2001

Rep. S185.95$15795

■ Sine-, square-.triangle- andseparate TTLsquare waveoutput ■

Frequency range:1Hz-100KHz

Portable VOMMultitester

Model $-4 Q95VM520 U*

20K1! VDC» 10 Kll VAC

HICKOK

Digital CB In-LineTester

$16995,

Reg. S399.00

100 MHz 8-Digit Counter

■ 20 Hz to 100 MHz Model MAX100range ■ LED display

■ Fully automatic

Reg. S150.00

$12750

Logic Monitor

• Automaticallydisplays static anddynamic logic •

Model LM-1 Works with DTL, HTL.

SCQ95 TTL, and CMOS • 1633 LED display

BE

r<—

AttacheStyleTool Case

Model TC100/ST«<* $27995

Service

MasterTool Kit

Model 9S-SM

JSk $4750

Weller'-Xcelite'

Proto B5EPreassembled

PB-104\Si""**49

Fully assembled breadboardcontains four QT-59S sockets,seven QT-59B bus strips and four5-way binding posts

er Lamp

ground and polished

lion I- i $/] Q95

MG10A ^<?

Proto Board withBuilt-in PowerSupplies

10095 Mode|^S3° PB-20:

30 MHz LEADERDual Trace

*89995 H

Model LBO-520

Weller'ControlledOutput SolderingStation

BSSBM PortableDigital CapacitanceMeter

Model 620

■ Measures

capacitance

Irom 0.1 pF to 1 Farad ■ Resolves to

0.1pF ■ 10 ranges lor accuracy and

resolution ■ 4 digit easy-to-read LED

display ■ 0.5% accuracy

6"x9" 3-Way Speaker

■ 20 oz. ceramic magnet .Model BP2000-69TR

$1495ea.

TelephoneAnswering

Modet 1500 snylftQCiCall Control *24933Rbj.S349.95 — — qkModel 1400 $1 99

CODEvD-PHONE

WAHL

SBES Cordless60 SolderingIron$2995

Model 7800

ThefunaZ-Sfitxt Model ssaa

Circuit Tester s2995

FREE

B pc. Tool Set (value$14.95} Willi $200.00purchase from this ad

Miniature High Fidelity3-Way Stereo Speakers$gg50 Ria s«9 95

ModelHF-9

t=s=3'/2-Digit 0,1% DigitalCapacitance Meter Model 3001

■ 9 ranges Irom 1999 pF to 199.9 «F

■ 0.1% of reading accuracy Reg. $H 70

S190.00 1 / U

DieiTAmiuiJiiiiEiiR Simpson 461

Complete with nickel-cadmium batteries, ACcharger/adapter, testleads $

In-Dash Car Stereos

8-Track Tape Player withAM/FM/MPX Radjo_

Model C-777 r

$5250

BSRX-10

Remote Control lorLights & Appliances

4 Pc Standard Slarter Kit • OrConsole ■ Two |2) Lamp ModuModule

5 Pc Ultrasonic Slarter Kit ■Command Console ■ One (I) Hanil2) Lamp Modules ■ One (1) Appli

I ill Siandaid Command Reg S87 95is » One (1) Appliance V7Q50

me |1) Otiiuii1 Ultrasonic Reg S1I2 95Held Remote Urn! ■ two JQQ95

Lamp Modules

Aupliance Modules

Wall Switch Modules

114.50 Standard Command Console S36.00■ 14.50 Ultrasonic Command Consulc*cQ OKJ14.50 ■■itti Maim Hriil n.'iimiii SS3':i

E&4ii>M'!'ho MHzPortable FrequencyCounter Reg .sjslqi

Stereo Power Booster

Model POW-40 t,

■ 40W stereo

2495 Bgg

FORDHAM

855 Conklin St.

Master Charge

Farmingdale. N.Y. 11735

■ EtankAmerlcard

■ VISA ■ CODa Money Order

■ Check

N.Y. Slate residents addappropriate sales tax

ADO F OH SHIPPING AND INSURANCE

tot 250.00 S 3.50

171.1 00 in 500,00 5.00

501.0010 750.00 7.50

I 751.00 Id 1000.00 10.00

over 1000.00 12.50

COO's eilra

Er°elel(800)645-9518

ALCO MINIATURE TOGGLE SWITCHESMTA106SPDT...MTA206DPDT ..

MTA 206 P-DPDT CENTR OFF '..'. S1.S

MSD 206 P-DPDT CENTER OFF LEVER SWITCH..... SI ,8

SCR'S

TRIACS

1.5A

GA

35A

PRV

1A

10A

25A

.45

.60

1.40

100

100

,45

.80

1.55

.70

.60

1.90

200

200

,84

1.30

2.10

1.20

1.40

2.60

■101)

400

1.30

1.90

3.10

1,80

3.60

GOO

ftoo

2.00

2.75

4.30 '

C for our catalog featuringi ransistors and Rectifiers145 Hampshire St., Cambridge, Mass

SOLID STATE SALES

P.O. BOX 74B

SOMERVILLE, MASS. 02143 TEL. (6171 547 7053

WE SHIP OVER 95%

OFOURORDERSTHE

DAY WE RECEIVE THEM

326 BYTE May 1980

Circle 308 on inquiry card.

DIGITAL RESEARCH COMPUTERS

(214) 494-1505

16K EPROM CARD-S 100 BUSS

FIRST TIME OFFERED!BLANK PC BOARD - $28

USES 2708s!

Thousands of personal and business systems around the worlduse this board with complete satisfaction. Puts 16K of softwareon line at ALL TIMES! Kit features a top quality soldermasked andsilk-screened PC board and first run parts and sockets. Anynumber of EPROM locations may be disabled to avoid anymemory conflicts. Fully buffered and has WAIT STATEcapabilities.

OUR 450 NS 2708'SARE S8.95 EA. WITHPURCHASE OF KIT

ASSEMBLED

AND FULLY TESTED

ADD $30

8K LOW POWER RAM KIT-S 100 BUSS

SALE

Jfi7-'lLte"'ri&.' Jiit"""--

$1195£

21L02(450 NS RAMS!)

Thousands of computer systems rely on this rugged, work horse,RAM board. Designed for error-free, NO HASSLE, systems use.

Blank PC Board w/Documentation

$29.95

Low Profile Socket Set .13.50

ASSEMBLED AND FULLYBURNED IN ADD $35

ALL ASSEMBLED BOARDSARE TESTED AT 4MHZ.

Support IC's (TTL & Regulators)

$9.75Bypass CAP'S (Disc & Tantalums)

$4.50

16K STATIC RAM KIT-S 100 BUSS

16K STATIC RAM SS-50 BUSS

PRICE CUT!

*225

KIT

III! IIIIIHIIIII

PRICE CUT!

I m I f

ISSlIESSlIlIIIIIi

iiiiiiiiiiiiiiii

BLANK PC BOARD W/DATA-$33

LOW PROFILE SOCKET SET-$12

SUPPORT IC'S & CAPS-$19.95

KIT FEATURES:

1 Addressable as four separate 4K Blocks.

ON BOARD BANK SELECT circuitry. (Cro-memco Standard'). Allows up to 512K on linel

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.

OUR #1 SELLINGRAM BOARD!

FULLY STATICAT DYNAMIC

KIT FEATURES:

1 Addressable on 16K Boundaries

2. Uses 2114 Static Ram

3 Runs at Full Speed

4. Double sided PC Board Solder maskand silk screened layout Gold fingers

5. All Parts and Sockets included

6. Low Power: Under 1.5 Amps Typical

BLANK PC BOARD—$26 COMPLETE SOCKET SET—$12SUPPORT IC'S AND CAPS—$19.95

FOR SWTPC6800 BUSS!

ASSEMBLED ANDTESTED - $35

MfcNN1- STEREO! A/eiv/

S-100 SOUND COMPUTER BOARD

Perfect lorOEM's

S-100 Z80 CPU CARD

COMPLETE KIT!

*84

95

(WITH DATA MANUAL)

BLANK PC

BOARD W/DATA

$31

At last, an S-100 Board that unleashes the full power of twounbelievable General I nstrumentsAY3-8910NMOS 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:. TWOGI 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 FLEXIBILITYBoth Basic and Assembly Language Programming examples are included

SOFTWARE:SCL Interpreter coming soon! Our new Sound Command Language interpreter alongwith the Register Examine/Modify (REM) routines and Sound Effects Library (SEL) willbe available soon in EPROM. SCL makes sound effects programming generally easierand quicker than that written in Basic or Assembly Language. An SCL users group willbe formed, and the best new SCL programs submitted will be added to the SoundEffects Library in EPROM.

*169

95

WIRED!NOT A KIT!

4 MHZ

ASSEMBLED AND TESTED! READY TO USE! Over 3 years of designefforts were required to produce a TRUE S-100 Z80 CPU at a genuinelybargain price! BRAND NEW!

FEATURES

* 2 or 4 MHZ Operation. * Generates MWRITE. so no front panel required.+ Jump on reset capability * 8080 Signals emulated for S-100 compatability* Top Quality PCB Silk Screened. Solder Masked. Gold Plated Contact Fingers

FOR4MHZ

SM#

LOW POWER - 300NS 8 FOR

2114 RAM SALE! $44

4K STATIC RAM'S. MAJOR BRAND, NEW PARTS.

These are the most sought after 2114s, LOW POWER and 300NS FAST.

8 FOR $44

NEW! G.I. COMPUTER SOUND CHIP

AY3-8910. As featured in July. 1979 BYTE! A fantastically powerful Sound& Music Generator. Perfect for use with any 8 Bit Microprocessor.Contains: 3 Tone Channels, Noise Generator, 3 Channels of AmplitudeControl. 16 Bit Envelope Period Control, 2-8 Bit Parallel I/O. 3 D to AConverters, plus much more! All in one 40 Pin DIP. Super easy to interfaceto the S-100 or other busses.SPECIAL OFFER: $14.95 each Add $3 for 60 page Data Manual.

Digital Research Computers

** (OF TEXAS) "

P.O. BOX 401565 • GARLAND, TEXAS 75040 • (214) 494-1505

TERMS: Add $1.00 postage, we pay balance. Orders undei $1b add 75Chandling. No COD. We accept Visa and MasterCharge. Tex. Res. add 5%Tax. Foreign orders (except Canada) add 20% P & H. 90 Day Money BackGuarantee on all items. Orders over $50. add 85C for insurance.

NOT ASSOCIATED WITH DIGITAL RESEARCH OF CALIFORNIA, THE SUPPLIERS OF CPM SOFTWARE.

Circle 309 on inquiry card.

BYTE May 1980 327

_

SEX IS NO SUBSTITUTE

for quality software from the SoftwareReview. This months offerings:

SOFTWARE MUSIC SYNTHESIS SYSTEM —From California Software, this superb 4 voicesynthesizer for 80B0IZ-80 systems proves thatsoftware can do anything hardware can do and itcan do it cheaper.For all CP M & N'DOS systems S79.95

OSBORNE CBASIC BUSINESS PROGRAMS —Complete set (A/R, A;P. GL, Payroll) in mostformats IDocumentation separate) • . . $100.00

QUIK-REF — Definitive Northstar Basic Cross-Reference Branch trace program. Machine codedfor extreme speed $21.50

DOS-POWER SYS/I — Machine code moduleprovides additional Northstar DOS capabilitiesincluding on-line file recovery, rename, file-locking,directory reformatting, and more .... $21.50

WORDSTAR — from Micropro. Super wordprocessor Reg. S500 Special offer .... $400

KELLY CARD GAMES — Classic algorithms.STUD. DRAW. ACEY-DUCEY, BLACKJACKNorthstar only $21.50

SUPER PILOT 4.1 — Acclaimed as the finest Pilotavailable. Includes tutorials on disk For Northstarusers only $49.95

ORDER FROM

The Software Review —

704 Solano Ave., Albany, CA 94706(415)527-7730

J & B Computer Products

We:Buy — Sell — Trade — Broker,

Mini To Mainframe Computers,Components to Complete Systems.

We Specialize in Basic Four™

We Supply:

Disc Packs and Cartridges.

Also: Formatted B/4™ Compatible

Packs-BBII

We Supply:

Standard and Custom Cable

We Will Be Pleased To Quote

Your Specs.

Dealer Inquiries Are Invited

J & B Computer Products

P.O. Box 3089 Simi Valley. Calif. 93063

Phone Number Available After

Responsible Requests.

GAMES

— FOR—

MICROPOLIS MOD II

At last, software written for MICROPOLISMOD II using MBASIC operating underMOOS. All games are delivered on a 5'i"floppy disk and include player instructions.M-VENTURE is based on Adventure foundon large computer systems. The M-GAMESfloppy disk contains 12 of the most popularcomputer games, including STARTREKM.Both M-VENTURE and M-GAMES are avail-able on a single floppy disk, M-BOTH.

• M-VENTURE $19.95

• M-GAMES $19.95

(Includes STARTREKM)

• M-BOTH $29.95

(Includes M-VENTURE & M-GAMES)

(California residents add 6 sales laxJ

M-SOFTWARE

21215 Merridy Street

Chatsworth, CA 91311

Circle 310 on inquiry card.

Circle 311 on inquiry card.

Circle 312 on inquiry card.

SPRINT 68MICROCOMPUTER

CONTROL COMPUTERDEVELOPMENT SYSTEM

6800 MPU, serial I/O, 48K RAM, dual 8"drives, WIZRD multitasking DOS,Editor, Assembler, 12K BASIC all for$3995.

SOFTWARE OPTIONS

C compiler, PL/W compiler, PASCAL

HARDWARE OPTIONS

EROM Programmer, analog I/O, parallelI/O, 488 GPIB

wixtik

Corp

1801 South StreetLafayette, IN 47904Phone: (317) 742-8428

Circle 313 on inquiry card.

PROPERTY MANAGEMENTSOFTWARE

• Full General Ledger

— user chart of accounts

— customized statements

• Checkwriter (or manual checks)

• Budgeting • Rent Roll

• OeSquency List • Vacancy List

• Lost Rent Report • Vendor Report

• Lease Expiration Report

• Real Estate Support

— income property analysis

— loan amortizations

— depreciation

Compatable with CP/M, TRS-80,Apple and P*ET. Demonstrationdiskette/manual $35.00, full system$650, dealer inquiries welcome.COD, VISA and MasterChargewelcome:

A-T Enterprises

221 N. Lois, La HabraCA 90631 • 213-947-2762

J INS AM °ata

, Manager

• CUSTOM DATA FILES

• FAST/EASY/MENU DRIVEN

• HELP COMMANDS

• KEYED RANDOM ACCESS

• MULTIPLE SEARCH KEYS

• PRIVACY ACCESS CODES

• WILD CARD SEARCH

For 16K-32K PET, Dual Disk, and Printer

FREE: LABEL PRINTER MODULEFREE: REPORT GENERATOR MODULESpecify CBM 2040 or COMPU/THINKPackage $150 User's Guide only $25

Introductory Demo Tape $5 Disk $ 8

Check or Money Order plus $2 Shipping

(NY residents add 8% Sales Tax)

-DEALER INQUIRIES WELCOMED-

JINI MICRO-SYSTEMS, Inc.

P.O.Box274-B • Bronx, NY 10463

Circle 314 on Inquiry card.

CARD FAMILY

FOR EXORcisor*/MICROMODULE* BUS:

MIKUL S8000 CPU CARD

Motorola 8 MHz 16 bit processor

4 channel DMA . . . PTM . . . ACIA

7 vectored interrupts

MIKUL B8001 MEMORY CARD

6/12K x 16 PROM . . . 16/32/4SK x 16 RAM

68000 a-sync cycle support

•Motorola TM

ALSO

6809 cards and custom design

TL Industries, Inc., 2573 Tracy Road

Northwood, OH 43619, 419-666-8144

16-BIT CARD FAMILY

HOW CAN I GROWB TREES?

ORDER MICRO B +™

• Get fast insertion, retrievaland deletion of index entries.

• Never need to reorganizeyour index; no matter howoften it is updated.

MICRO B+ SOURCE CODE $195MICRO B + DEMO DISK $25

SHIPPING $2 USA. $5 FOREIGN

Available in 8" lormat lor CBASIC-II

and MICROSOFT Basic Version 5.

P-^"""™ j^^^^^* 2606 Johnson DriveH'AIDt /"MM Columbia. Mo. 65201I Min VSwIVI 314-445-3304

Check/VISA/Mastercharge

Circle 315 on inquiry card.

Quick Service

Competitive Pricing

WABASH

MAXI-MYTE

DISKETTES

CONTINUOUS

LABELS

STOCK & CUSTOMCOMPUTER FORMS

COMPUTER RIBBONS

FREE CATALOG

AVAILABLE

GEM Business Systems, Ltd.

60 East 42nd StreetNew York, N. Y. 10017

(212) 682-9005

oooooooooooooo

Circle 316 on inquiry card.,..

Circle 317 on inquiry card.

Circle 318 on Inquiry card.

Circle 320 on inquiry card.

FREE!

AxiomEX-801 PETPrinter(withgraphics)$ 475.00Axiom EX-820 PET Plotter $ 749.00

Anderson Jacobson 841 Selectric .

Leedex Video 100 12" Monitor

HeathWH19Terminal(factoryasm.) .Heath WH14 Printer (factory asm.) .IEEE-RS232 PrinterAdaptorforPET .

Up to $170 in merchandise with purchaseof one of following PET-CBM items I!!

BETSI PET to S-100 Interface $ 119.00

PET Connectors-Parallel or IEEE $ 1.95

Cassette Port $ 1.45

Hands on Basic with a PET $ 10.15

Programming the 6502 (Zaks) $ 10.45

6502 Applications Book (Zaks) $ 10.45

6500 Manuals (MOS Technology) .... $ 6.50

Programming a Microcomputer: 6502 . $ 7.756502 Assembly Language

(Osborne) NEW! $ 9.90

All Book and Software Prices are Discounted

PET Personal Computer Guide (Osborne)... S 12.75PETandthelEEE-488Bus(Osborne).... $ 12.756502 Software Cookbook (Scelbi) $ 9.45

Cassettes (all tapes guaranteed) AGFA PE611Premium quality, high out put lownoise in 5 screwhousing with labels:

C-10 10/5.65 50/25.00 100/48.00C-30 10/6.90 50/30.00 100/57.00

$1015.00$ 119.00

. $ 770.00$ 735.00

. $ 88.00

PET SPECIALS *FREE

PET 16N 16K full size graphics keyboard $995 $130PET 16B 16K full size business keyboard $995 S130PET 32N 32K full size graphics keyboard $1295 S170PET 32B 32K full size business keyboard $1295 $170PET 8N 8K full size graphics keyboard $ 795 $100PET 2040 DUAL DISK DRIVE-343,000 bytes $1295 $170PET 2022 Tractor Feed Printer $ 795 $100

PET 2023 Pressure Feed Printer $ 695 $ 70

PET C2N External Cassette Deck $ 95 $ 12

Used 8K PETs (limited quantities) $ 495

+ EDUCATIONAL DISCOUNTS .X.

w Buy 2 PET Computers, gel 1 FREE w

•Free Merchandise with Purchase of PET-CBM Item.

2716 EPROM (5 volt) ... $29.00 5@> 27.00 10® 25.00

4116 RAM 16K x 1 $7.50 8 @ 7.10

2114 L 450 $5.35 20 @ 4.95 80 @ 4.45

2114 L 300 $6.10 20 @ 5.65 80 ® 5.05

6502 $8.35 10 @ 7.85 40 @ 7.35

6522 $7.15 10@6.95 40 @ 6.45

6520 $5.15 10 @ 4.90 40 @ 4.45

6532 $7.90 10 @ 7.40 40 O 6.85

6502A $9.50

6504 $7.95

21L02 $ .90

6550 RAM (PET 8K) $12.70

S-100 Wire Wrap $2.85 10 @ 2.65

S-100 Solder Tail $2.35 10@2.15

KIM-1 $159(add$30forpowersupply)SYM-1 $209

BAS-1 Microsoft ROM Basic for SYM $ 85

Memory Plus (KIM, SYM, AIM) $195

SYM Assembler in ROM $ 85

KIM 16K Static RAM $284

Seawell Motherboard - 4K RAM Space ... $139

KTM-2/80 Synertek Video Board $349

S-100 16K Static RAM Kit SALE $198

TIS PET Workbooks - set of 6 $ 21.50

Dust Cover for PET $ 7.45

ATARI-INTRODUCTORY SPECIAL

ATARI 400. Atari 800 and all Atari Modules 20% OFF.

Programmers Toolkit - PET ROM Utilities. $ 44.90

Sargon II (TRS-80 or Apple) NEW! $ 24.90

MicrochessforPET(PeterJennings) $ 17.90

VisibleMusicMonitor(4Voice)forPET... $ 29.90

KL-4M 4 Voice Music Board (PET) $ 34.90

CmC Word Processor (8K $25) (16K $34)Adventures by Scott Adams 15% Off

SALE

! (write for quantity prices)

™] Scotch 8" Disks .. . 10/$31.00

' Scotch SVt" Disks . 10/$31.50

Verbatim 5'A" Disks 10/$26.50

Diskette Storage Pages 10/$ 3.95

Disk Library Cases 8" - $2.95 5" - $2.15

BASF 6V Disks 10/$28.00

BASF 8" Disks 10/$29.00

MINIMAX

by COMPU/THINK

115 E. Stump RoadMontgomeryville, PA 18936

(215)699-8386699-5826

A B Computers

MINIMAX I |.8 Megabyte Disks) S3395MINIMAX II (2.4 Megabyte Disks) $4495SPECIAL — MINIMAX prices include Compu/Think PAGEMATE Database and Report Writer at no charge.

WRITE FOR COMPLETE CATALOG

Add $1.00 per order for shipping.

We pay balance of UPS surface charges on all prepaid orders.

o*b

xtt*-

MODEL 550BANTUM'CRT

MICROPROCESSORS

Z80A $13.95

6502 11.95

8035 19.95

8080A 4.95

TMS 9900 29.95

Interactive CRT terminal with high resol-ution 12" diagonal 24 x 80 display and a7 > 10 character matrix. All 128 ASCIIcharacters, highlighted numeric pad,RS-232C interface with eleven switch-able baud rates (110 to 9600). Inversevideo and transparent modes, switch-able parity, full or half duplex and stopbits, absolute and relative cursor controlfrom host computer. 115V, 60Hz.

$799.00

DYNAMIC RAMS

4116-250ns

8 for $ 59.95

8080 SUPPORT

82128214821682248228823882438251825382558257

S2350

$2.504.502.503.255.956.257.956.95

19.505.95

17.95

$7.95

PROMS

17022708

2716—5 Volt27582732

DIP SWITCHES

3Pos. $1.00 6Pos. $1.10

4Pos. 1.00 7Pos. 1.15

5Pos. 1.00 8Pos. 1.20

ZIP DIP II SOCKETS

16 Pin $5.50

24 Pin 7.50

40 Pin 10.25

MOTHER BOARDS

USRT

UARTS

TR1602B $3.95

TR1863 5.95

DISC CONTROLLER

1771 $26.95

1791 37.95

6 Slot Bare Board

6 Slot Kit

12 Slot Bare Board12 Slot Kit18 Slot Bare Board18 Slot Kit

$22.4547.4537.4587.4557.45

127.45

RS-232 CONNECTORS

DB25P - Male Plug $2.95

DB25S - Female Socket 3.60

DB25C - Cover 1.50

100% 90 DAY MONEY BACK GUARANTEE ON ALL ITEMS SOLDSEND $2.00 for 1980 CATALOG

THE STAR MODEMFrom Livermore

$179.00

0 to 300 baud data rate. Compatible withBell 103 and 113; CCITT. Answer/Originate. Full/Half Duplex. Special selftest features.

EPROM ERASER

Compact, durable, quality UV Lamp forerasing EPROM's. Features a specialsafety lock to prevent accidental expos-ure. Erases up to four devices (2708,2716, 2732, 1702A, 5203Q, 5304Q,etc.) simultaneously.UV-4/20 $68.95

o*t

vtf*-

CO**

TERMS OF SALE: Cash, checks, money orders. VISA. Master Charge. Minimum order $10.00. Texas residents add 5% sales tax. Minimum shipping andhandling charge $2.50. COD orders addS1.15 COD fee U.S funds only D&B rated firms call tor open account.

DAL-COMP M/O DIV. 2560 ELECTRONIC LANE, SUITE 108, DALLAS, TEX. 75220 • (214) 350-6895

Circle 321 on inquiry card.

BYTE May 1980 329

page

DEAL#1

Hobby Wire Wrap Starter Package

BW2630 WWTool $19.95

BT30 #30 Bit 3.95

BC1 Batteries & Charger 14.95•Kit #1 Wire Kit 9.95

Regular Price $48.80

yoSJ

"Kit #1 Contains 900 pes. of precut wirein asst. sizes.

Choose from Red, Blue. White, Black.Green, Orange, Violet, Yellow, or assort-ment.

DEAL #2

Industrial Wire Wrap Starter Package

BW928BF WWTool $52.95

BT30I #30 Bit& Sleeve.. 29.50

BC1 Batteries & Charger 14.95

'Kit #3 Wire Kit 32.95

Regular Price ... $130.35

$119

95

•Kit #2 Contains 4000 pes. of precutwire in asst. sizes.

Choose from Red, Blue, White, Black,Green, Orange, Violet, Yellow or assort-ment.

* * BIG DEAL * *

IC Sockets by the Tube

RN HIGH RELIABILITYeliminates trouble. "Sidewipe"contacts make 100% greatersurface contact with the wide,flat sides of your IC leads forpositive electrical connection.

WIRE WRAPSOCKETS

Size

Quantity/Tube Price ea.

• Price/Tube

08 pin14

52

30

.39

.46

$20.28$13.80

3-level Gold

16

26

.50

$13.00

Closed EntryDesign

182022

232118

.68.85

.42

$15.64$17.85$16.56

•Sockets sold at theseprices by the tube only.

242840

171510

.941.231.60

$15.95$18.45$16.00

Above prices include gold up

to $800/oz.

SOLDER TAIL

Low Profile TinClosed EntryDesign

'Sockets sold at theseprices by the tube only.

1<P/pin(over 5 tubes)

3/4<P/pin(over 100 tubes)

See tube quantities above.

ORDERING INFORMATION

Orders under $25 include $2 handlingAll prepaid orders shipped UPS Ppd.Visa, MC & COD's charged shippingAll prices good through cover dateMost orders shipped next day.

Limited to products Page Ditigal stocks. All discounts are off of list price.Call or write for list prices.

10% off on all OK hobby products!

10% off on all Bishop Graphics products!

5% off on all Vector products!

|J32[© 135 E. Chestnut Street 5A, Monrovia, California 91016 Phone (213) 357-5005

330 BYTE May 1980

Circle 328 on inquiry card.

CaMForn.a DiqiTAl

Post Office Box 3097 B • Torrance, California 90503

With Purchase of TheINTEGRAL DATA 440

Paper Tteer

Your Choice, $200 Value

1) Graphics Option Package

2) Interface for APPLE II3JTRS-80 Printer Interface

California Digital has resentlyrescarched the complete lowcost printer market. It is ouropinion that the IDS 440 PaperTiger is. without doubt, themost versatile and offers thebest value of any printer cost-ing under $1,000.

This quality dot matrix printerincorporates such features assoftware selectable character size to allow print densities upto 132characters per line- Full forms handling capabilities and tractorfeed mechansim adjustable to 9.5". The Paper Tiger is engineeredto accept either parallel or'RS232 serial ASCII. 110/220V.50/60Hz.:;;:;:»»» $995,00 plus shipping *****

iCTORS

RS 232

DB25Pmale plug & hood

■c

*3.95

5H

DB25S female

$3.95

Edge

Connectors

GOLD100 PIN

IMSAI/ALTAIR

Imsai solder .12Sx.250Imsai w/w.l25centersAltair soldertail.UOroxSPECIALS22/44 Kim eyelet. 156"25/50 solder tab .156"36/72 wide post ww.156

• 2.95 3/$ 7.50S4.95 3/113.0045.95 3/S15.00

41.95 3/45.0041.09 3/42.0041.95 3/45.00

Authorized Distributor

Scotch"

Data Products

740-0740/2741-0743-0740-32

[DM soft format.Double sidr; softD ouble densityDouble/ D ouble8" H ard sector

744-10K10X16) 5 l/4"miniLibrary ease for any above834 A Data CassetteDC 100 MinicartridgeD C 300 D ata Cartridge020( ) Disk Cartridge

10 Pak

$39.00

65. 00

53. 00

70.00

30.00

30.00

Add $3.00

5.50

00

20.00

89. 00

50+

3. 506. 00

4. 906. 603. 503. 50

S-100 Mother Board

QuietBuss

*29.95

8803-1818 slotIMSAI

I The Quiet Buss Irom California Industrial IsI quality engineered No snort cuts have been takenI to produce Ihrs mother board. Active terminationI circuitry prevents noise and crosstalk Manulac-. lured Irom extra Heavy FR-a epoxy glass

Ui.LLi.:LLUjlMi

*149

MOTOROLA

New factory sur-plus. M3000/3211Motorola CRTmonitors.20 MHz bandwidthElectronics term-inate into singleten pin {. 156 )edge connector.Requires DC pow-er supply

TELETYPE MODEL 43

4320 KEYBOARD

TTL AAA *1050

RS232....AAK 1150

Friction .., AAE

103 Modem AAB 1575

1100 shipping

rEb

[nrr plastic library case

■"BfT r r with purchase of each box of ....■ »■-■- Memorex minidiskettes. »5 value.

DISKETTES

Apple Plus ISK

AllUS Rr-jtrn 39rUIDS RcK«it WADDS Ht-m-nt BOHjiL-lUnt- 1-120ll.iieltlne 1500

PRINTERS

•-joo uoo LFUI isoo

Teletype Model *3 <nsa32)Teletype Mode) 40(132 col.)

NEC Spin writer flf.lO R/O

Atl.e.IeK t

Anniit

UP U 500

lipasoi

.540 R/O plastic;1M KSR plastic

n Cat Acoustic

DISK DRIVES

Sng&ct sasoor b" (loppy ;Sugar! Saboir a" hard sec.Lobo / Two Slnifiart 001 a withpower supplv jjiJ eAfllOSUre I

QasShagart aoi with

power supply mil enclosureLolio tiarti drive Tor Applu

10 meE'byte 7110a '.

Lobo hartl drive for TRSBU !

LoboJ00-t S 1/V for TRS80Vista V -00 for T 11580 UOtrkl

APPLE COMPATIBLE PRODUCTS

Apple disk dmApple drive wilApple Parallel

Interfacead tor Apple,arc Supertulk

S-100 BOARDSThink/Toys Switclibo.ini I/O(rtKluctil EcCAior.ii.i IToilucHMiiIlUi IB-3 Extend. tt.Oftc

Artec ivwioo WlreWrap Protc

SL) 64K Eipandoralu Memory16 BIT S-ioo BOARDSCal. Digital CAL-fleTecniar8086Seattle Computeru BOBfi

i.oiibr.it Houti/3t)u:i

Ithaca lnicravalenm Z-B000M15CEI. I.ANE OU.«

Shugarr Associates

SA800-R Floppy Disk Drive

The mosi cost effective way lo store data proc-essing information, when random recall is aprime factor. The SA800 is fully compatiblewith the IBM 3740 format. Write protect cir-cuitry, low maintenance & Shugart quality.

544950

MEMORY

TRS-80S|APPLE II

16k memory (8) 4116's

Installation is simple. Anyone who hasever changed a spark plug should be able ito up-grade his microcomputer.How can California Digital offer thesememory up-grade sets at 25% below our competition?Simple, we buy in volume, wholesale to dealers andsell the balance directly to owners of personal micro-systems. These 16K dynamic memory circuits arefactory prime and unconditionally guaranteed for onefull year. N O W, before you change your mind, pickup the telephone and order your up-grade memoryfrom California Digital. Add $3 for TRS80 jumpers.

STATIC

21L02 450nS.21L02 250nS.2114 11<X4 4502114 1KX4 3004044 4Kxl 450

4044 41<xl 250

4045 lKx'l 4504045 IKxl 2505257 low pow.

1-311. 191. 495.958. 955.959.958. 959.955. 95

32-99 100-5C -999

1. 395.508.505. 509. 508.509. 505. 50

.951. 255.258.005. 259. 008.009.005. 00

XEROX 800

WORD PROCESSING

KEYBOARD

ASCII ENCODED

This 77 key word processing keybimanufactured by Micros witch for I

Xerox 1)00 word processing system.The keyboard outputs a seven bit ASCIIcode along Willi ;ui eighth lilt tlmt allowsmost keys lo shift and double function .15

special characters. Extra large " Tab *■Return " keys are designed into the layuuiof the keyboard to emulate the IBM Sulec-trie. 17 illuminated keys serve for speei;word processing codes. The keyboard inequipped with two thumbwheel swllchidefining line width.Original Xerox acquisition over $400.00California Digital USED price only $4b. 0Excellent comi. Documentation included

e in tile

for

4. 80 4. 60

SPECIAL CIRCUITS

Z80A 4 MHz. 24. 95

B0BOA CPU 9. 95

8085 22.50

8086 Intel 16bils 85. 00rMS9900 16 bits 49.95

AY5-1013A UART 4.95Floppy Disc ControllersWD 1771 single D. 39. 95WD 1781 Double D 65.00WD 1791 D/D3740 *

E PROMS 1-15 16-63 64+

1702A 2K 4.95 4.50

2708 BK 9.95 9.50

27165vl6K 29.95 27.50

2716 T I 24.88 20.00

2532 85.00 *

.00

.00

ACOUSTIC

MODEM

The Omnltec model 71)1 Modem connectsthe RS-232 serial port of your computeror peripheral device acoustically lo yourtelephone line.

Place the telephones handset iof the modem, instantly your computerthe world of dig-ital information.Ball and full duplex ability.

MiniatureSwitches

me&ewt

w

your choicec 10 50 100 Ik

».5»0 J.88 .81.73.66 |SPDT Miniature Toggles

7101 CS.K ON NONE OH

7107 jbt 0N-OFF(iniit ON) I

7108 CK ON-'iimniiiiit OH) |7103 CK ON OFF ONRotary 3P-4-Pos.Rotary 3P-6-Pos.PushB 1N.0.) 5.39ea.4/$l

DIP Switch

s .ilnni: Willi -j. Hilly udc? iC<!i] wordpriicL-sBin;■ivsoluiion screen is c

niis.r ASCII elLiractfr!

is switch selectable n50 (plus shipping! Hit-

JJ29

75 100 IB

SI 19 1.09 .97 .83

If y 4

oropos.

, *|a]«aj^

PORTABLE DATA ENTRY SYSTEM -'

These used data terminals were originally designed for chain store inventory con-trol and order entry systems. The operator enters the inventory control number,merchandise on hand and the unit price. After all pertinent data has been entered intothe recorder, the main warehouse is telephoned, the handsel is placed in the acousticcoupler and all the recorded information is transmitted back to the master computer.With a Uttle Imagination and one of these portable entry systems, you should be ableto exchange programs and computer information with associates across the country.'ed from service in working condition. Original cost 52,500.

Each s

with:

■Portable Cassette Drive Uni!■Removable Entry Kevboard«ith LED Display "

■DB3S Cable■Shoulder starp•bull Documental

DISCOUNT ' l

Wire WrapXenter

IC SOCKETS

Wire wrapea. 25 50

low profile•a. 25 50

>

17' 16 15

14

37' 36 35

18 17 16

16

38 37 36

19 18 17

24

99 93 85

36 35 34

40

169 155 139

63 60 58

529.95

BW630

50-t KYNARSiSf

.98 500 1.000 11,000

>9. 515. J105.

(213)679-9001

nierchandise sold by Califory, no COD's. Orders are

Circle 322 on inquiry card.

lise sold by California Digital is premium grade.3D's. Orders are shipped the same day received.^sidents add 6%. Foreign orders add 10%.$25, when accompanied by payment, are shippedle. Otherwise, please add $2.

BYTE May 1980 331

SN7-100NSN7-101NSN7402NSN7-103NSN7404NSN7405NSN/406NSN7407NSN740BNSN7409NSN7410NSN74MNSN74I2NSN7.it 3NSN7414NSN7416NSN74I7NSN7420NSN7421N5NM22NSN7423NSN7425NSN7426NSN7427NSN7429NSN7430NSN7432NSN7437NSN7438NSN7J39NSN7440NSN7441NSN7442NSNM.1.1NSN7444NSN7445NSN7446NSN7447NSN/448NSNM50NSN74fi1NSN7453NSN7454NSN7459NSN7460NSN7470NSN7472NSN/473NSN747.1NSN7475NSN74 7GNSN7479NSN74B0NSN74Q1NSN7482NSN74S3NSN7485NSN7486NSN7489NSN7490NSN749INSN7492NSN7493NSN7494NSN7495NSN7496NSN7497NSN74100NSN74107NSN74109NSN74116NSN74121NSN74I22N

7400 I 74LS00

SN74123NSN74125N

SN74126NSN7412BNSN74132NSN74136NSN74139NSN74141NSN74142NSN74143NSN74144NSN74T45NSN74147NSN74148NSN74160NSN74151NSN74I52NSN74153NSN74I54NSN74I55NSN74156NSN74157NSN7415BNSNM160NSN/4161NSN74162NSN74163NSN74164NSN74165NSN74166NSN741G7NSN74170NSN74172NSN74I73NSN74174NSN74175NSN74I76NSN74I77NSN74179NSN741BONSN74liilNSN74182NSN74IB4NSN741B5NSN74186NSN74188NSN74190NSN7419INSNM192NSN74193NSN74194NSN74195NSN74196NSN74197NSN7419BNSN74199NSN74221NSN74251NSN74273NSN74279NSN74283NSN74284NSN74285NSN74290NSN74298NSN74365NSN74366NSN74367NSN74368NSN74390NSN74393NSN74490N

CD40(X)CD4001CD4002CD4006CD-1007CD400B

CD-1003

CD4010CD40!1CD40I2

CD4Q13

CD4014CD4015

CD4D16

CD4017

CD4018

CD4019

CD4020CD4021C04022CD4023

CD4024C04025CD4027CD4028C04029CD4030CD4031CD4032CD4034CD403&CD403?'CD4CM0CD404 1CD4042CD4043

CD4044CD4046CD-1047CD404BCD4D49CD40S0CD-IOMCD4052CD4053CD4055CD4056CD4059C040B0CD406RCD4069CD4070CD4071CD4072CD4073CD4076CD4076CD4077CD4078CD408ICD40B2CD4085CD4089

3.252.153.25

I 19I 95

CD4093

CD4094

CD409B

CD4099

MCI4408

MCM409

UC14410

MCI 4412

MCM415

MC14419

C04501

CD4502

C04S03

CD4505

CD4506

C04507

CD4508

CD4510

CD4511

CD4512

CD4515

CD4516

CD4516

CD4520

CD4555

CD4556

CD456G

74COO

74C02

74C04

74C08

74C10

74C14

74C20

74C30

74C32

74C42

74C48

74C73

74C74

74C85

74CB9

74C90

74C93

74C95

74C107

74C151

74C154

74C157

74C160

U74CC161

74C163

74C164

74C173

74C174

74C175

74C192

74C193

74C195

74C922

74C923

MM80C95

MM80C97

2 952 95295

215390

390

CMOS

2 4922512 95129512.9512.958.954 95.391.65

3951.39

1.391.39395

1.85

1 192.493 502.10

2 392 302 392392 592752.752.392392397 956 951 50125

74LS00N74LS01N74LS02N74LS03N74LS04N74LS05N74LS08N74LS09N74LS10N74LS11N74LS12N74LS13N74LS14N74LS15N74LS20N7 4LS21N74LS22N74LS26N74LS27N74LS28N74L530N74LS32N74LS37N74LS38N74LS40N74LS42N74LS47N74LS48N74LS51N74LS54N74LS55N74LS73N74LS74N74LS75N74LS76N74LS78N74LS83AN74LS85Nf4LS86N74LS90N74LS92N74LS93N74LS95N74LS96N74LS107N74LS109N74LS112N74LS113N74LS114N74LS122N74LS123N74LS124N74LS125N74LS126N74LS132N74LSI36N74LS138N74LS139N74LS145N74LS148N74LS151N74LS153N74LS154N74LS155N74LS156N74LS157N74LS158N74LS160N74LS161N74LS162N74LS163N

74LS164N

74LS165N

74LS166N

74LS168N

74LS169N

74LS170N

74LS173N

74LS174N

74LS175N

74LS181N

74LS190N

74LS191N

74LS192N

74LS193N

74LS194N

74LS195N

74L5198N

74LS197N

74LS221N

74LS240N

74LS241N

74LS242N

74LS243N

74LS244N

74LS245N

74LS247N

74LS248N

74LS249N

74LS251N

74L5253N

74LS257N

74LS258N

74LS259N

74LS260N

74LS261N

74LS266N

74LS273N

74LS275N

74LS279N

74LS283N

74LS290N

74LS293N

74LS295M

74LS298N

74LS324N

74LS347N

74LS34BN

74LS352N

74LS353N

74LS363N

74LS365N

74LS366N

74LS367N

74LS368N

74LS373N

74LS374N

74LS375N

74LS377N

74LS385N

74LS386N

74LS390N

74LS393N

74LS395N

74LS399N

74LS424N

74LS668N

74LS670N

81LS95N

81LS96N

81LS97N

B1LS98N

1 951.951 702.95

2.95

LINEAR

78H05

78M06

78MG

LM105H

LM108AH

LM300H

LM331CN/H

LM304H

LM305H

LM306H

LM307CN/H

LM308CN/H

LM309K

LM310CN

LM31 TD/CN/I-

LM312H

LM317T

LM31BCN/H

LM319H/H

LM320K-XX*

LM320T-XX-

LM320H-XX-

LM323K

LM324N

LM339N

LW340K-XX-

LW340T-XX-

LM340H-XX-

LM344H

LM348N

LM358CN

LM360N

LM372N

LM376N

LM377N

LM390CN/N

LM381N

LM383T

t M386N

LM387N

LM390N

NE531V7T

NE555V

NE556N

NE561T

NE562B

NE565N/H

NE566H/V

NE567V/H

NE592N

LM702H

LM709N/H

LM710N/H

LM7HN/H

LM715N

LM723N/H

LM733N/H

LM739N

LM741CN/H

LM741CN-14

LM747N/H

LM748N/H

LM760CN

LM1310N

MC1488N

MC1489N

LM1496N

LM1556N

LM1800M

LM1820N

LM1B50N

LM1889N

LM2111N

LM2900N

LM2901N

LM2917N

CA3013T

CA3018T

CA3021T

CA3023T

CA3035T

CA3039T

CA3046T

LM3053N

CA3059N

CA3060N

CA3062N

LM30G5N

CA3080N

CA30B1N

CA3082N

CA3083N

CA3086N

CA30B9M

CA3096M

CA3097N

CA3130T

CA3140T

CA3146N

CA3160T

CA3190N

CA3401N

MC3423N

MC3460N

SG3524N

CA3600N

LM390ON

LM3905N

LM3909N

RC4131N

RC4I3GN

RC4151N

RC4194

RC4195

ULN2001

ULN2O03

SN75450N

SN75451N

SN75452N

SN75453N

SN75454N

SN75491N

SN75492N

SN75493N

SN75494N

2.491.992492.492 49

RETAIL STORES OPEN MON-SAT1310 "B" E. Edinger STORE 674 El Camino Real

ADVANCED

COMPUTERPRODUCTS

.5%. 3'idigii 19

Range DVM, W LCD displays

runs 200 hrs on 1 batlery. 10 Meg

Ohm Input. 1 yr. guarantee, made in

U.S.A., test leads included.

Avaiiabia AccdhsoiIob

RC-3 11BV AC Adapter S7.50

CC-3D«loifP.idil.;<J Vinyl CiirivnnCiinc J7.50VP-10 Xin DCV Ww Adaptei/

\ Vr [Texas INSTRUMENTS

Calculator Discount Prices

Tl 30 SP

Tl 50

TI55

TI57

TI58C

TI59

Tl PC 100C

Tl 1035

H 1750

Tl 5025

Tl 5040 . .

Tl Dala Card

Tl Data Chron

Tl Business Analyst II

Tl Programmer

TIMBA

Tl Business Card

Tl Speak & Spell

Tl Dataman

Tl Spelling B

Tl Lil' Professor

Tl Vowel Power

Tl Super Stumpers 4. 5. 6

Tl Super Slurnpers 7. 8

17.95399535955495979521995146 951595199569 9579.95269537 954a95489557 9534 95G4 95199527.95. 12.9512.95

MONITORS

Sanyo9" S169.95

Sanyo 15" 279.00

Leedex 12" 139.95

Motorola 12". High Resolution.

22 MHz. OEM Model

"M3000-340 219.00

Zenith 13" Color Monitor .. 499.00

MGA 13" Color TV 349.00

VAMP 19"Color Monitor,., 575.00VAMP 15" Color Monitor... 449.00

TRS-80/APPLE

MEMORY EXPANSION KITS

4116's

16K (200/250 ns.)

8 pes. lor $62.95w/instructions & jumpers.

Call ForVolume Pricing

^HAZELTINE" TERMINALS

Model 1400 S749.00 Model1500 S1U85O0Model 1410 SB2500 Model 1510 S124500Model 1420 S94500 McdeM5?0 S14950D

Continental Specialties

Model 3001 Digital Capacitance Meter 27500Model 333 Tn-Mcde Comparator 29500

Model LM-3 40-cliannel Logic Monitor 5B500Model LM-1 Logic Monitor 60.00

Model LM-Z Logic Monitor 14700

MDde!20D1 Swrerabte Function Generator 18600Model 5001 Universal Counier-Tuner 36000

Model 60DI 650 MHz Frequency Cornier 385 00MJU-100 100 MHz Portable Frequency Counter

149 00PS-50D 500 MHz Decade Prescaler 70 00

MAX-50 50 MHz Handheld Frequency Counter

7700MAX-55D 550 MHz Handheld Frequency Counter

165.00Model 4001 Pulse Generator 83500

Model QP-1 Digital Pulser 8300

Logic Probes

Model LP-1 Dignai Logic Probe 50 00

Model LP-2 Economy Logic Probe 28 00

Model LP-3 Hign Speed Logic Probe 77 00

Model LHt-1 Logic Probe Kit 2195

Logic Probe Accessories 21

Model LTC-1. LTC-Z Logical Analysis Kits 220/250

Apple II. 16K

or Apple II. Plus $990

16K Apple Upgrade Kit $62.95

Hi-Speed Serial I/OCentronics Printer I/OApplesoft II FirmwareApple ClockInlrol X-10 SystemInuol X-10 ControllerAll Music Synthesizer1G Ch Analog Input2 Ch Analog Output13-Key KeypadVisi-Calc

$174 95 0S65 Oigi-Seclw

199 95 Apple Graphics Tablet

174 95 DC Hayes Modem II ;

189 95 Disk II w/Controller !

26995 Disk It

17995 Pascal Lang System ,

25995 Parallel Printer Card .

24995 Communications Card I

164 95 Business Software Pkg ,

11995 Corvus 10 Megabyte Dnl149 95

S349 00

Integer ROM Card

517500

79500

Proto Card.

2195

34995

M & R Modulator

2995

475 00

Sanyo Cassette

54 95

575 00

16K Upgrade Kil

6295

475 00

Apple Radio Car

15900

165.00

8 Floppy Controller

35000

21000

Heunstcs Speechtab

179 00

62500

Romplus +

16900

e

Supertalker

27900

4625 00

Cashier

25000

A ATARI 800 & 400

Personal Computer System

ATARI 800 $899.00-■ ATARI 400 $499.00

ATARI 800 Includes: Computer Console, BASIC Lang. Cartridge. EducationSystem Master Cartridge, BASIC Language Programming Manual. 800 Operator'sManual w/Notebook, Atari 410 Program Recorder, 8K RAM Module. PowerSupply, TV Switch Box.

Pi riph trill

Rogiani HetonffitSolium - (DM tinnim

Educalum System Masre C.iMwVyAlii-. BASICAsicniUer Oetiigftisvetbaii

hlu

SDpB BrcjUxil1"

tiiutilkm Sylllm Cliullt Pninini

US Histay

US Guvemiiiml

Supciwwiy Skdls

WoM liis!i*y iWesltini

Bsc ScciMJqy/

Coinsding fcocWu>ei

fin-r.-ji,", m Aicainlmg

Wiylcs

GhmI i:i.i;,si:ii rFngistil

B11511KW1 C«tiiimniCJH«ns

B.1SC Psyctiotogy

EBKIirt Wrilmq

Auto Mechancs

PincvkS 0) i conotici

Basic Eiecinciiy

Baste AkjWxa

fin: Clri ltd frafnn Cliwrlll

Guft; ici basic PWyrwnwntj

BASIC Gairt Pingisms

35 DOI 35 003500

Dmnn) CrniliDliei P^"

Cattle Ctft'cv PanJ^stici Contrrjfcfr Pa«

Texas Instruments

99/4 PERSONAL COMPUTER

lound and Graphics-and aic - All Built In.

$1099.00

Superior Color. Music. Sound and Graphics - and a■■A Powerful Extended Basic - All Built In.

Csi commodorePET L0WSAS $775.00

DISCOUNT PRICES

?00l-l6KBlreg]

?00l-3JKB(regi?022 BU-Col Do! M

?7i0a 3023- aa-Ca Pu.n PJ3t- f^-rer 695CO

SrSBO 204D Diul U>m Diik tjnvt 125000

9«0D Pel In IEEE ClUe 399b

l?M0O IEEE id IEEE CaUc 499^

mow C?N t.l .11 (;.i:.M'iic Ueck 9SM

^9500

ft lemoM.

$174.95

without $154.95

cruise conlrol

An onboarcl navigatmui compute) lor .luiomooilcs. 1r licks, and'Kieaiional whicics Fciiui'-. mi <■ ignlio! lutl marugc-ment sysiem tup compute miiiiiirciionerj quail; crystalDm tmniier plus many oiiwi lunciions

HAND HELDCOMPUTER SPORTS GAMES

$18.95ea

ELECTRONIC ELECTRONIC

FOOTBALL SOCCER

\-£ Texos Instruments

LANGUAGE TRANSLATORTHAT SPEAKS

The world's firsthandheld elec-tronic translatorto pronounce anddisplay | words,phrases and sen-tences. I

LANGUAGE MODULES ^»Bel

ENGLISH .SPANISH .-.^FRENCH • GERMAN "O't aacl

Texas Instruments

ELECTRONIC DIGITALTHERMOSTAT

The Inlellgeni Way ToCut Energy Costs Yeaf-_ RoundUse Only The EnergyYou Really Need -WithThe Touch 01 A Bullon

round A fully

comlod system for ine home. 11 can aciually pay

lor itsell in less than one season

Sugg. Reg 12500

ACP Price $^ Q495

SINGLE BOARD COMPUTER SELECTION GUIDE

BOARD PROCESSOR ACP PRICE ENCLOSURE

KIM-1 6502 169.00 Add 29.95

SYM-1 6502 249.00 Add 39.95

Cromemco Z80 409.00 N/A

SD-SBC100 280 239.00 N/A

AIM 65 6502 375.00 Add 49.95

CosmacVip 1802 199.00 Inc.

STORE 1310 "B" E. Edinger

#1 Santa Ana. CA 92705

Showrooms, Retail, Warehouse

#2 Tustln, CA 92680

Specializing In Systems

P.O. Box 17329 Irvine, Calif. 92713

Direct Order Lines: (714) 558-8813

(800) 854-8230 or (800) 854-8241

FOR INTERNATIONAL ORDERS:1401 E. Borchard (714)953-0604Santa Ana, CA92705 TWX: 910-595-1565

332 BYTE May 1980

lAEMVNCED

COMPUTERfPRODUCTS^V^

100 32K luses 2114) J^**„

ASSEMBLED Kil J**r

45Dns 499.00 450ns 469.00

250ns 53900 250ns 499 GO

Bare Board 49 95Bare Board w/all pans less mem 99.95

' 16K lS-100 Compatible)

• Low Howe

• 2 MHz Of 4 MHz

• 4K Bank Addressable

• Extended Memory Management

• Assembled & Tested2 MHz S250.004 MHz . S265.00

• LOGOS I OKASSEMBLED450ns 149.95 KIT 450ns 12595250ns 169.95 250ns 14995

Bare PC Board w/Dala S21 95

"Special Offer' Buy I4| 8K 450ns Kits S1 1 7 (

ipatipiei .-»

MtfO>M-

gemenl

JfflEBfiHC Q

The VISTA V-80Disk Drive System

• 23% nee storage capacity titanTRS-80

■ 130 clay warranly

■ 40 Hack patch al NO CHARGE

^11

Single dine systemTwo drive systemFoui drive systemTwo dn*e cable

S 395.00S 770.00SI 450.005 29.95S 39.95

THE VISTA V-20O FOR EXIDY

WME-M

400

:,n.;if »f,h!

WOO l a

WW

lw* iir.ni

V200[ 30

-

lOnw

■;. ■'■.,-

WOUf 32

2MK

3 0m>tDouHt Bwd

@"

DC-500 HARD DISK INTERFACE

m*D 0IS1S.IS15H" I - HIM 00. ,:. Km* II Mil U«ve

r ■■..- THSBU W«r>l■ «MS ISOOCD

CC WOCtfKUB-THSaCWWH 1SCO00

cnwMT - iM n lyjooo

DC MJU Cot»i#c ■ S-100 1500 DO

LOW-COST ADD-ON DISKSUBSYSTEM KIT

* (2) 8" Drives •tSTN.

*■ VISTA Floppy Controller /cost s»».\

Card \1299.00/

* Power Supply and Inter- y ylace Cable

* CP/M Disk Operating System

* Box ol 10 Diskettes

IMS STATIC RAM BOARDS

Memory Mapping * Low Pqv,

mo

o°

# Phantom * Assembled & tested

Recommended by Alphamicrosystems

250 ns. 450 ns.

8K Static S209.00 S189.00

16K Static $449.00 S399.00

32K Static S729.00 S629.00

ANADEX PRINTER new apple »e«sionModel DP-8000 compact, impact, parallel orserial. Sprocket feed. 80 cols,84 lines/mm., bi-direc!'Onal.

New only $875.00

DP-8000AP (lor Apple)S875 00

SD SYSTEMS BOARDS

kit AS5EM

SBC 100 Single Bo.nl Computer I2MH.-I S26500 S 34900

SBC 200 Single Board Computer iJMHzi 289 00 399 00

ZflO Slater. System 319 00 449 00

VDB 80?4 Video Display Board 335 00 459 00

VS1M-1H30P) II 325 00 429 00

Eipandtl PROM 11 5 00 225 00

5D100 Computer SyMomw/64fl C99500

SD2Q0 COfflpule' SyUern W/64K /99b 00

• Special TRS80 Schematic. .

• Expansion Interlace Schematic

• Expansion Interface Connector

S 4 95

S 4.95

7.95

EXPANDORAM II MEMORY KITS

* Bank Selectable * Uses 4116 200 ns.

* Write Protect * Power 8VDC. ±16VDC

* Phantom * Up to 4 MHzExpando64Kitid116i

16K S290.00 48K $444.00

32K S365 00 64K S519 00

LETTER QUALITY SELECTRIC!

TRENDATA 1000 COMMUNICATION STATION

. jfi - "" Supplied with docu-

^& -^eaaVj^^Jt** rnenialion. Powerinput: 115VAC± 10%,60Hz. 200 Watts.Printer platen, 15"wide. Desk size: 20" x35" wide x 23" deep.Excellent condition.Guaranteed. Shpg.Wt 150 lbs.

CAT NO. TDP-RE232 S1399.00

CAT. NO. TDP-TTRS80 1399.00

CAT NO. TDP-EBCD1C 1299.00

UV "EpronV' Eraser

Model UVs-11E S69.95

Holds A Eprom's al a lime.Backed by 45 years

Model S-52T... S265,00

EMAKO-20.. Reg $777.00 $599.00

UNBELIEVABLE!!

125 Caps. 60 Ipm-VerticalFormal Unn - 96 Charac-ters- Upper/Lower Case-4.5" to 9.5" Adjustable■ 80 col/40 col doublewidth-Full 96 <*« ASCII

EMAKO-22 S799.O0

Prints a 132 col/line. Available with parallel or serialoutput at same price.

MIKA20 $1280.00

9x7. 125 cps 136 characters/lineFull 15" width. Super for business applicationsrequiring large IBM lormat paper.

NEW CENTRONICS 737 PRINTER

Uses any paper roll, fanfold.single sheets, 96 characterASCII, 7 x 7 dot matrix, 50CPS. RS232 or parallel I/O

WOW! S899.00

Z-80/Z-00A/8080 CPU BOARD

# On board 2708 • 2708 included (450ns.I

* Power on jump # completely socketed

• Z-80 Assembled and Tested Si 85.00

• Z-80 Kit SI 29.95

• Z-80 Bare PC Board S 34.95

* For 4MHz Speed Add S15.00

8080A Kit S 99.95

8080A Assembled S149.95

S-100 MOTHERBOARD SPECIAL

8 slot expandable w/9 conn.

reg $69.96 NOW S52.95

SIEMEN'S FLOPPY SALE

• Special buy while SIEMENSsupply lasts. S429.00

• 8" Drive with Double- SHUGARTDensity 801R

• 90 Day Warranty $475.00

ACOUSTIC MODEM

NOVATION CAT'" /L^^=>f7

0-300 Baud

Bell 103

Answer, Originate S169.00

680O MICROMODULE" PRICE LIST

MODEL NO DESCRIPTION PRICE

9600A

9609

9601 10 Slot Mother Board 17500

9602 Card Cage 75 00

9603 8 Slot Motno Board I00O0

9604 Power Supply 275 00

9605 DC Mout Power Supply 325 0096'0 Ulility Proto Board 39 0013611 Artlh Pi rx/Memory Moduli' 495009612 Buttered Ultli'y Prolo Board 49 00

9616 32K EPROM/RAM Module 25000

9617 EPROM Programming Head 250009620 16 Cuannf Parallel I/O Module 295 009622 Senai-ParaHei I/O Module 325 00

it 2 ■ ■•.•■■ v.i! RAM Module 470ns 395 00

9629 32K Static RAM 450ni. 695 009629A 32K Static RAM 200ns 695 00

9630 Card Enlendei 68 00Multiple Programmable Timer 395 008 Channel Dupie« Se-.ai i/O Mod 395 00Intelligent Tape Connoiler 550 0032/32 I/O Module 27500Contact Closure Module 350.00

U'JPOPULATED BOARDS lAlsa Available)

96409650

9655

DATA BOOKS • COMPUTER BOOKS

19B0 IC Master 59 95 Intel MCS 80 Manual 7 9b

NSC TTL Data 3 95 Intel MCS 40 Manual 4 95

NSC Linear 4 95 AMD 80B0A Manual 5 95

NSC Linear Ann Noioi II 3 35 AMD ScrioRfiy Databoak 4 95

NSC CMOS 3 95 AMI MOS'LSIOala 3 95

NSC Memory 3 95 Gl MOS/LSI Data 4 95

Intel OalabOOk * 95 Hams Analog Databook 4 35

Intel MCS 85 Manual 7 50 Tl Linear Control Dala 3 95

SALE * OSBORNE BOOKS • SALE

80B0A Programming 8*50. 7 75

6800 Programming tTSO 7 75

7aOP'r-^.imm,ng eSO 7 75

Vol II Somp RmI Wun'orfMc'i a 'Bmot-r 3t>6Q 2750

, Mb ■' ■ •■■■ i ■ .. ■' "■■. ■ ,. B ■ :•- 2*00. 18 50

Mir ' ■.'■ ■■ . it 7TM5Q. 1850SALE • DILITMIUM COMPUTER BOOKS * SALE

Understanding Computers "9-9*. 7 95

BOBOMicrocomjjulei E.oer.mems n^ft. 11 95

B..-.(.nning GASlC 'SS*. 6 95

BoB>ivierS Glossary & Guide IT^fc 5 95

in k.u.i r.'

ly Guidi

b Languafle Pfogra

l ■■

-r-9*.

7-9*.T-5-96 t

6 95

FIRST TO OFFER PRIME PRODUCTS TO THE HOBBYIST AT FAIR PRICES'

1. PrOVeil Quality Factory Tested procucts only.

2. Guaranteed Satisfaction

3. Over $1,000,000.00 Inventory

1980 CATALOG NOW AVAILABLE.

Send S2.00 (or your copy of the most complete catalog ot computer products.A must for the serious computer user.

MICROPROCESSORS

28001 'Glut to 8Mb

28002 I6bit lo64K

ZBO...

Z60A

f B13B50I

2650 t

CD 1802

8080A

8080A-4MM;

SALE B085

29012901 A

Sunc

2903

TMS9900JL

CP1600

6502

6502 A

IM610O

8 50199513 9514 95

99014 9529 9549 9539 95

6B0OB2 0MHI 19 95

6802P 17 95

8035 19 95

6755 49 95

8748 69 95

6809 64 9560S 6 69 95

ADVANCED SUPPORT

AM951 I Anil! Piocesscn 175 00

9512 Anlli Processor 17500

9513 Univ Timing 7995AM9517 DMA Conl roller 18 95AM9519 Univei-.al Interrupt 18 95

Z-80 SUPPORT CHIPS

Z80-PIO 2 5 MHz il 75

Z00A-PIO 4.0 MH; 13 95

ZBO-CTC 2 5 MH; !! 7fi

2B0A-CTC 40 MH; 1295

ZBO-DMA 2 5MH* 29 95

ZBOA-OMA 4 o MHz 36 95

ZBOSIO/0 2 5 MHz 35 95

ZiWA-SiO/0 4 0 MHZ 39 40

Z00-SIO/1 25 MH? 359B

ZBOA-SIO/I 40 MH( 3940

ZBOSIO/2 2 5 MHj 35 95

Z80SIO/2 4 0 MH* 39 40

8080/8085 SUPPORT

8!55'8156l(0 24 95

8755 I/O w.tn Eprom 64 95

620? Dyn Ham Cnnt 34 95

8205/74S 138 Ducodnr 3 95

8212 B bit I/O 2 ?5

8214 pnontylnl 525

8216 Bus Driver 2 75

8224 Clrxli Gen 2 95

8224-4 |4MHj| 9 75

B22G Bur) Dnver 3 95

8T2B Bus Dnvor 2 95

B22B Sy:. Control 5 50

«2:ii: Sya Com 550

8251 Prog I'O 6 95

B253lnt Timer 16 95

8255 Prog I/O 6.50

8257 Prog DMA 16 95

8259 Prog Inl I 7 95

8275 CRT Controller 5995

8279 Prog Keyboard 1895

6800 SUPPORT CHIPS

6810 128'8 Ram 4 756820 PIA 5956621 PIA 6 506B2B Pnoriiy mt 9 956B34-t 512 . 8 Eninm 1695634h'HD4C505CFlT Cunt 39 956B4/ColoiCRT 49956850 ACIA 5 956B52 Senai Adapter 5 956860 Modem 10956862 Modulaloi 11 956871A 1 OMH; OSC 25956B75 8 256880 Bus Duvet 2 95MC6848B68047

1802 SUPPORT CHIPS

1821 SCD 2K RAM 25 00

'■■.■.■ set; ,'M ■ -1 HAM

1824 CD :i? .8 (3AM1B52 t;DBI)il I/O1B54 Unit1856 CD I/O1B57CDI/0

12 95

6502 SUPPORT CHIPS

6522 Mult

t.5."'.!)-W.'(r<).!(!(].1.0056532

2716-5V

29 95

27i6-r:v, lav

29 95

275B-5V

29 95

5203AQ

13 95

5204 AQ

14 95

IM 5B10

390

SALE B323 32 ■ 0....

2.95

82S23 6 95

B2S131 1495

B2SI37 14 95

NOTE. WE PROGRAM PROMS

CHARACTER GEN.

25I3-ADM3 |5VI Lower 14 95

MCM6571 11 75

MCM6571A 11 75

MCM6574 1450

MCM657S 1450

UARTS/BAUD RATE

IMS i>0'1 .!>'.' '.".'.

IM6403

2 350 usn t

SALETR1473B

KEYBOARD ENCODERS

AY5- liODHD016574C92271C923

9 959 959 95

STATIC RAMS

' .'4

25-99

too

Z1LO? 450ns

1 30

99

2lL02 250n^

i 59

1 55

3 75

3 65

J 55

2 90

> 70

3 ifi

6 95

750

890

21l4L-450ns (4045] 5 50

525

4 75

7 50

690

4044 450ns

5 95

4 75

EMM4200A

9 75

8 75

7 9S

EMM4402

7 95

7 25

6 25

EMM 4804

12 50

11 SO

9 95

5101OE

7 95

7 95

10 95

10 25

B2S

AMD913031

P2125/93425 [45"

i 9 95

B35

8 25

fiSOB IK . 1 CM05

5518 IK . t CMOS

,T4S1B9L"1 lur Ram

B147towPOwBl-4K

DYNAMIC RAMS

416/4116 16KH6

Setol B 4165

4H5QK|16 Pin)

4050 4K . 1 |1B Pn

4080 4K . 1 [22 Pir

409S4K > 1 116 Ph

2104 4K> 1 U6 P"

4027 4K . 1 |16 P«

5261 1 95

64K ;

inni

1 95

•1 *!>

S280 4 95 RAMS 6604b290 1245 $175.00 6002

4.8S

1 50

CHARGE COUPLED DEVICES

LOSS'S

(CCD

-i|.i.i..i-

l,niliinli'-,illl|ill'1llWi!

iMi-n.mli.r Quantity

S18.95 each

(reg. 43.O0)

SOCKETS

Lo-Pro Soldortnll

ZERO INSERTION FORCE

3Pin S550 24Pm S7 50 40Pm S1025

$ LED READOUTS

4 95

16 959 9510 951095

FLOPPY DISK I/O

771-018 4M.n,Tioppv 2495

A/D CONVERTERS

8700 5 mr Bmary '3 51

140SL66 inl 39

1408LBS Oil 5 9

DACOl OloA 5 9

TV CHIPS/SOUND

WAVEFORM GEN.

8038 Function Gen 3 95

MC4024VCO 2 95

LM566VCO '95

XR2206 Function Generatm 5 25SHIFT REGISTERS

MM5O0H DualZS 50

MM505liN riudl 256 295

MM50I.0N Dual 128 295

2510A Dual 100 I 95

2647 Quad 80 4 95

3341 Dual 80 4 95

3351 40. 9 FIFO 17 95

3357 Ouad BO 6 95

9403 16' 4 FIFO 24 95

940H ' 0 Bit Sequence' 9 95

CTSDIPSWITCHES

CTS206'2 I 75 CTS206-7 l 75

CTS206'4 I 75 CTS206-8 1 95

CTS206-5 1 75 CTS206-9 1 95

CTS206-6 l 75 CTS206-10 1 95

CONNECTORS (GOLD)

Set a Hood Saie22.44 WW S 7 KIM43/86WAV S3 MOT

50:100 S-100 Conn.>-.:,F50-100£-100 Cnnra.,-iiii

2 95h504 95

IC SPECIAL PURCHASE

ICm' fofb Plr^^,?opw'','■rB.■,,''

8 9523 95

ICM 7205 CMOS LED SlOpwatti- - -i-e-

1995

iCM 7207 Oscmator ConHOiU'i

7 50

[CM 71'08 Seven Decade Counter

IB 95

tCM 7209 Clock Generator

6 95

iCL 7107 3'' Digii AyDiLEDt

14 95

MC14433P 3'. Digit A/D Convert*.

13 95

iCL B2i i Voltage Rete-onco

1 95

LM 39CN Baltery On AjdiO Ann

3/100

LM 1800N PlL FMSterero

3/1 00

LM IB20N AM Radio

3/1 00

LM 1850N Ground Faull IC

3/1 00

LM 2900N Quail Amplifier

2/1 00

LM 2901 N|HM| Quad Comparator

2/1 00

LM2917NFreq to Voll Conv

2/1 99

Ay-3*3560 4*> digit DMM

24 95

AV-5-3507 40MHz DVM

IVEM 4953 Moslt;! Smolu' D0(e«O(

11 95

27SOU 32 - (1 Prom (IM 56001

2 95

Gl 15M F> channel Moslel

1 49

ULN2003A / channel Driver

99

10146 IK « 1 ECL Ram

9 95

MCM 14505 64 t).t Sialic Ram

6 95

7520/25 50 LM 377

l 25

1488/1489 2/1 99 LM 3B7

1 25

MK5014C-1IC 3/199 LM 330?

3/1 99

74S89 3/1 99 LM 4558

3/1 99

7BH05K 695 RC4I36

2/1 99

LM323K 4 95 RC4131

2/199

MCI.372 895 COM 5027

39 95

COM 5037

49 95

PROCESSOR TECHNOLOGY

NKRA Dynamic Memory Bo.urt-.. Assem

bled

Without RAM PROM ni Data Delay L.i

U.-itoMKpi" Board

FLOPPY DISKS

CERTIFIED! 40 TRACKS

DOUBLE DENSITY

8 3740 IBM Compat

$4 39

53 99

5'. Soil Sector 40 Track

S3 99

Vista compute' diskettes by Verbatim Minimum

order 10 For quanniy miichnse!. pleas

call

ALSO AVAILABLE

DOUBLE SIDED

DOUBLE DENSITY

PAKOF 10 5'.

S5G40

8'

Sf.:i 30

Floppy ■Jit.-' haid Itoiea .mil uppHealoiS

CALL

NAKED PC

Z-BOCPUiltn.-,rrti

534 95

8080A CPU

34 95

bk Siat« ram iLogost 24 95

t^K Sialic RAM (211

4| 2<>95

32K Statu. RAM(211

4t 29 95

Floppy I/O iTarbelli

39 95

Cassette 1 0 iTarbell

29 95

8K Eupiwi (2 7081

24 95

1 702 Eprom Board

30 OC

2708/2716 Eprom illhacai 3495

2708 2716EeromiWMG 3000

HimHiMi- Cluck

34 95

ACPPtCitr.Bd (3MCs

ni 27 95

2220

Vecicnaaoa 11 sloiMB 29 95

ACP E.tender */Con

n 16 95

Video interlace iSSM

3195

Parallel Interlace (SSMi 31 95

13SlolMotnerBoaro

,VMCi J2 5^

9 Sioi MMm* Board (V/MCi 29 95

8 Slot MufM-r n->nanoabiei 34 95

Proc-Tech Bare Boaids CALL

COMPUTER SPECIALS

.1ST SALE

Apple II Plus V./16K

1195 990

PET 2001-16N

995 895

Ei>dyS<Hcererw.'16K

1099

Compucoluf M w/8K

1895 1795

6990 6290

Horizon 1 w/32K

CALL

TEIPI208w/32K0uai

4995 2495

1 loppy & CRT

Pascal Micioengine

IPSI ItiL'O [iialilnRO

3295.2695

Aoade« dp booo

995 B75

595 395

Centronics MicioS-i

595 525

Soroc IQ 120

995 795

Teletype Model 43

1349 1150

Hi Plot Plotter

1085 899

HiPini Digitizer

795 735

895 794

Atari BOO

999 B99

Alan 400

549 499

Tl 99/4

1150 1099

149 139

Centronics 737

995 899

TrencomT-100

375 349

Trer.com T-300

595 525

Sanyo 9" Moniloi

220 169

Sanyo 15" Moniior

295 249

M(>i(>r(il.1,22 MHz

Momio-

SOCKET SPECIALS

16 Pin Ww2L

40 Pm iwwJL

TERMS: UM check M C VISAAMEX CB or COD COD reaves25=0 deposit Charge Orders pleaseinclude e.pi.ation date Fo.e.on payU S Funds O'der av pnone ma.i orTWX MINIMUM S1000 Please m-

ionai tbs For an add 70c to- ado.-ionai ibs FOREIGN Add 10". smp-„ng and handling CODsSI 85e*i.aJO 1 lesponsibie lor typos Some

RETAIL STORES OPEN MON-SATSTORE 1310 "B" E. Edlnger STORE 674 El Camlno Real

#1 Santa Ana, CA 92705 #2 Tustln, CA 926SO

Showrooms, Retail, Warehouse Specializing In Systems

P.O. Box 17329 Irvine, Calif. 92713

Direct Order Lines: (714) 558-8813

(800) 854-8230 or (800) 854-8241

FOR INTERNATIONAL ORDERS:1401 E. Bore hard (714)953-0604Santa Ana, CA92705 TWX: 910-595-1565

Circle 323 on inquiry card.

BYTE May 1980 333

*

The Supermarket for TRS-80

/VOO "Oil V^OlYl|30n@nTS (and other computers, too)

In stock now immediate delivery.

The VISTA V-80Disk Drive System

• 23%more storage capacitythan TRS-80 _ ^

• 120 day warranty

• 40 track patch at NOCHARGE ~

Single drive system $ 395.00

Two drive system $ 770.00

Four drive system $ 1450.00

Two drive cable $ 29.95

Four drive cable $ 39.95

The VISTA V-80 Expansion Module

• Provides double densitymodification to yourcurrent Radio Shackinterface (lets you formatdiskettes in either singleor double density).

• Increases storagecapacity up to 204Kbytes (on single 40track drive).

• Includes all hardware

§239.00 software

The VISTA Model II

• Provides one, two orthree drives.

• Adds up to 1.5 millionbytes of on-line storage.

• 120 day warranty

• Does everything RadioShack's expansionsystem will do...for less!

$1000.00 Single drive

Expansion System$1550.00 Two drive Expansion System$2100.00 Three drive Expansion System$ 525.00 Additional drives alone

The TRS-80 Printers

Centronics 730... $945.00

7x7 dot matrix-

80 column ^

Anadex

DP8000... $895.009x7 dot matrix-80 column

VISTA

Printer... $745.005x7 dot matrix-80 column

Cables $27.50 each

Add On Drives

MPI B51 40 Track, Double

Density-204K $275.00

MPI B52 Dual Head, Double

Densitv-408K $375.00

Siemens FDD100-5 40 Track Double

Density 204K $275.00

Siemens FDD100-5 Flippy,

records both sides $290.00

Siemens FDD100-8 8" Single

Sided Drive $448.00

Other Products

1. VISTA Verbatim diskettes (hard or soft sector) Certified40 track $ 38.95

2. 16K RPM upgrade kits, guaranteed for 120 days.PRIME PRODUCT $ 74.50

3. NEW! DOS + $ 110.00

4. LNW expansion bare board $ 66.95

5. H.C. Pennington book, TRS-80 Disk

and Other Mysteries $ 18.95

6. DDT Disco-Tech disk drive timer $ 19.95

7. Cryptext (An Encryption Module) $299.00

The VISTA V-200 for Exidy

• Completely packaged system, tested and ready to plug in, includes:power supply, two 40 track drives, case, controller, all cabling andtotal CPM documentation.

• Storage capacity from 400K to 1.2 meg.

• System software-VISTA CP/M Disk Operating System and BASIC-E Compilerrecorded on 5-1 /A" diskettes.

Price: Starting as low as $1199.00

Bffff

CALL TOLL-FREE 800-854-8017

•TRS-80 is a registered trademark ol Radio Shack

The Vista Computer Company 1401 Borchard Street "Santa Ana, California 92705*714/953-0523

334 BYTE May 1980

Circle 324 on inquiry card.

Unclassified Ads

UNCLASSIFIED POLICY: Readers who are soliciting or giving advice, or who have equipment to buy, sellor swap should send in a clearly typed notice to that effect. To be considered for publication, an advertisementmust be clearly noncommercial, typed double spaced on plain white paper, contain 75 words or less, and includecomplete name and address information.

These notices are free of charge and will be printed one time only on a space available basis. Notices can beaccepted from individuals or bona fide computer users clubs only. We can engage in no correspondence on theseand your confirmation of placement is appearance in an issue of BYTE.

Please note that it may take three or four months for an ad to appear in the magazine.

WANTED: Printer for use with Apple II. Will trade (or sell)Nikon FTN camera with f 1.4 lens, Speedlight and Ring-light units, filters, closeup rings, and many other attach-ments. Write for complete list and send description ofprinter. Also, will sell Applesoft II read-only memorycard for $100 or highest bid. Gene Boggess, Star RoutePOB 220-6, Columbus MS 39701, (601) 327-6555.

FOR SALE: BYTE, Kilobaud, Interface Age; 1977 and 1978plus some odd issues. Best offer. Les Palenik, 25 AllviewCres, Toronto Ontario, CANADA M2J 2R4.

FOR SALE: 16 DIP (4 K by 1-bit) dynamic programmablememories (a set of eight). Motorola 7839; 250 ns chips.Interchangeable with TMS 4027, Intel 2104A-3,MK 4096-6, and many other brands. In excellent condi-tion, used approximately twenty hours. I upgraded myTRS-80with 16 K chips. Will sell for $35. Daryl Holder, Rt#2 POB 260-C, Loretto TN 38469, (615) 853-6740 after4 PM.

FOR SALE: Complete ready-to-go SwTPC system. 6800/1upgraded to a 6800/2, 28 K, MP-T board, CT-64 in custo-mized cabinet, Hitachi 12-inch with direct videointerface, PR-40 with parallel interface, AC-30, JPC TC-34800 bps tape interface with CFM/3 operating system.All documentation, assembly instructions, user guides,and source listings included. Software: three BASICs,three Assemblers, two Editors, Disassembler, Tracer,Relocator, games, and more. $1950. Allen Porter, 493Selfridge Dr, Colorado Springs CO 80916, (303) 574-4146.

FOR SALE: I have four Shugart SA400 disk drives for$285 each and two Shugart SA801 disk drives for $420each. Need money fast; will take good offer. They workgreat and were bought in 1979. Four drive cables for $20.David Sparks, 5232 Cornell Ave, Westminster CA 92683,(714)997-7640.

FOR SALE: 6800 Microprocessor Trainer by Heathkit,Model ET-3400. Includes all manuals, built and testedtrainer, programmed learning course (ET-3401), speciallybuilt peripheral interface adapter experiment board, andall parts for experiments. $365 value, sell for $315.Excellent condition. James Temple, 24 Spruce Ave,Bethpage NY 11714, (516) 822-6083.

FOR SALE: ESAT 200B 80/24 terminal, $220; GRI 756keyboard with case, $60; Leedex Video 100 monitor,$100; SD Z80 starter system with 4 K programmablememory, added operating system for video display on2 K erasable-programmable read-only memory, $260. Allassembled, little used, perfect working condition.G Kish, 1621 Payne, Wichita KS 67203, (316) 262-7315.

FOR SALE: Heathkit (Motorola 6800 processor) com-puter and the Heath H9 video terminal. Computer has4 K memory expandable to 64 K. Includes BASIC in read-only memory, double-function keypad on computer con-sole, 1 K monitor also with access to memory and pro-cessor registers, 8-bit parallel and serial input/output(I/O) with EIA or 20 mA current loop. Cassette interfaceand cables. Complete documentation and operationmanuals. Burned in for one hundred hours. Asking $480.Osi McReynolds, Rt #1 POB 71-B, Coeburn VA 24230,(703) 395-3797.

FOR SALE: PerSci Model 277 dual-diskette drive with aModel 1070 intelligent diskette controller. CapacityVi megabytes. All books and line diagrams included.Part of a purchased system that was used for sixmonths. James Holle, 9613 W Lincoln Ave, West Allis Wl53214, (414) 541-9808.

FOR SALE: S-100: Vector Graphic 8 K static program-mable memory (250 ns), $120. Ithaca Audio Z80A pro-cessor (4 MHz), $120. SSM IO-4 (four parallel and twoserial ports), $100. SSM PB-1 2708/2716 programmableread-only memory programmer, $110. SSM VB-1B videointerface, $100. ECT rack-mount card cage with ThinkerToys Wunderbuss 20-slot mother board and all connec-tors, $175. All boards assembled and tested, used lessthan twenty-five hours. Will consider best offer. Sendmoney order to Richard Haendel, 2500 Nonesuch Rd Apt16-G, Abilene TX 79605, (915) 692-5405.

FOR SALE: PolyMorphic video terminal interface (VTI)board for S-100 systems. Video is spotty, but also can beused as parallel input port (8212 on board) and 1 K pro-grammable memory. Fully socketed, never used, videoshould be easily fixable. $75 or best offer. Roger Bul-dain, 601 N Francis, Lansing Ml 48912, (517) 337-2278.

FOR SALE: Heathkit ET-3400 Microprocessor Trainerwith EE-3401 self-instruction program. Extra memorychips and components. Assembled and in excellent con-dition. Asking $150. William Porti, Second St, Evans CityPA 16033,(412)538-5454.

WANTED: Program libraries (manuals) for obsolete butworking HP-9100A and/or HP-9100B desktop calcu-lators. Thomas H Richardson, Kansas Wesleyan, Deptof Chemistry, Salina KS 67401.

FOR SALE: E-HUH 8100 S-100 bus expansion interfacefor TRS-80. On-board programmable UART, serial andparallel input/output (I/O), 16 K, 250 ns programmablememory, six card slots. All enclosed in custom metalcabinet with power supply. Full hardware and softwaredocumentation. Ready to plug in and turn 16 K systeminto 32 K. Cables included. Must sell, $700 value only$500. Michael Lesser, 14623 Pine Glen Cir, Lutz FL33549, (813) 971-8492 nights.

FOR SALE: S-100 system; IMSAI front panel with vector18-slot mother board, in case with power supply, $200;IMSAI MIO, $100; 8 K WMC Static Mem-1, $100; two 4 Kstatic, $50 each; Ithaca Audio Z80 processor, $125;Cromemco Bytesaver, $125. Above boards operating insystem. Tarbell Floppy-Disk Controller, partiallyassembled, $125; three IBM 8-inch FD33 floppy disks,one complete, one less interface card, and one lessmotor and interface card, all three for $225. Digitronicshigh-speed paper tape, with 8-inch autospooler, $100;TDL S-100 case, $20. John Potter, 5439 Eadie PI, WestPalm Beach FL 33407, (305) 686-4666.

FOR SALE: Two Viatron 21s, one robot printer. $500 forthree units. Also, SwTPC 6800 and CT-1024, $250. G Lud-wig, POB 408, Rice Lake Wl 54868, (715) 234-2680.

FOR SALE: Crossassembler for M6800 microprocessor.4-kilo word program written in BASIC for HP-2000A.Directly usable in other HPs. With simple changes, itassembles languages of other 8-bit microprocessors.Program supports same properties as Motorola's owncrossassembler. Program on paper tape, full documen-tation, user manual, and two-year full support; $163 (in-cludes postage). For manual and documentation, send$3. If required: program in other languages or on othermedia. Panu Pietikainen, Rauduntie 11 H, SF-02130Espoo 13, FINLAND.

WANTED: Copy of Z80 Assembler listing from BYTENybbles library. Harlan Michael, 315 Valley Vista Dr,Jackson MS 39211, (601) 982-6533 days or (601) 956-5268evenings.

FOR SALE: Three Heath 4 K by 16 memory boards. All inexcellent condition with documentation. $100 each, orall three for $270. Dan Buckler, 6115 A 42nd PI, Hyatts-ville MD 20781, (301) 927-0765.

FOR TRADE: Compucolor game programs for other

homemade game programs written for the CompucolorII. Programs must be 8 K or less. Paul Weisberg, POB2453, Melfort Saskatchewan, CANADA S0E 1A0, (306)752-3566.

FOR SALE: Five new single-board 8080Amicroprocessors, completely assembled and tested.Each includes 1 K by 8 erasable-programmable read-only memory and 256 by 8 programmable memory. Com-plete documentation, featured in CO magazine April,May, June 1979. $50 each. Platteter, 1315 Q St, BedfordIN 47421, (812) 279-6265.

WANTED: Ohio Scientific Superboard lis with allmanuals and documentation, up to $150 paid dependingon year and condition. Send year and condition for myoffer. For Sale: Tl 99/4 microcomputer. Paid $1150, firstcertified check for $1075 gets it. Brand new and still inoriginal carton. Or will trade Tl 99/4 for $950 plus OhioScientific Superboard II in good condition. GreggBeasey, 15 Cardinal Ln, East Islip NY 11730.

FOR SALE: Control Data Corp 10 megabytes disk drivefor AlphaMicro AM-500 system. Elmer G Mitchell, 152018th St, Huntsville TX, (713) 291-3447.

WANTED: I have a small amount of 8080 equipment (pro-cessor, a few support chips) and a large supply of otherstuff (74xx, MM3501, etc) and would like to buy or tradefor anything 6800ish (processor, bareboard, support,etc). Give a hand to an uprooted American. R M Bownes,146 Warren Rd, Donaghdee County Down, NORTHERNIRELAND BT21 OPQ. PS: Please use airmail, it's a lotfaster.

WANTED: Drawings and schematics for making an elec-trical sleep device, and other schematics for experimen-tal hypnosis. K de Groot, P-Lastmanstr. 7, Helmond,HOLLAND.

WANTED: Heathkit Microprocessor Trainer ET-3400 andMemory I/O Accessory ETA-3400 for use with HeathkitMicroprocessor Course. Will trade for Teletype printerparts, and/or cash. Please write and give details (ie:assembled/unassembled and if the unit(s) are opera-tional). George Kelm, POB 160, Yap Island GU 96943.First class mail for fastest reply, US Domestic PostOffice rates.

February BOMB ResultsGraph Theory

Readers of BYTE expressed aburning interest in "A Computer-Controlled Wood Stove" by SteveCiarcia (page 32). Steve won firstplace in the voting, his fourthfirst-place finish in as manymonths. Second place in the tallywent to John A Lehman for "AFinancial Analysis Program"(page 192). Judging from com-ments written on the BOMBcards, many readers werefascinated by an example of thebalance sheet for MITS, Inc. Thirdplace was taken by Ted Carter for"Implementing Dynamic DataStructures with BASIC Files"(page 92). Fourth place was takenby Robert A Morris for "Com-parison of Some High-LevelLanguages" (page 128).

May 1980 © BYTE Publications Inc 335

ReaderService

To get further information on the products advertising in BYTE, fill out the reader service card with youname and address. Then circle the appropriate numbers for the advertisers you select from the list. Add a15-cent stamp to the card, then drop it in the mail. Not only do you gain information, but our advertisers areencouraged to use the marketplace provided by BYTE. This helps us bring you a bigger BYTE. 'Corresponddirectly with company.

Inq

jiry No. Page No.

291

Farnsworth Computer 320

174

FMG Corp 249

320

AB Computers 329

103

Folio Books 174, 175

117

ABW Corp 195

307

Fordham Radio Supply 326

19)

Ackerman Digital 259

268

Frederick Computer Prod 308

50

(ADDS) Applied Digital

226

Futureworld 278

Data Sys 87

107

GW Computers Ltd 182

323

Adv Computer Prod 332, 333

Game Design

200

AL Industries 265

(Taito America) 294

267

ALL Electronics 308

318

GEM Business Sys 328

83

Altos 142, 143

6

General Business Comp 16

44

Anadex Inc 79

29

Gimix 58

257

Ancrona 304

204

Global Parameters 268

109

Anderson Jacobson 184

104

Godbout Electronics 177

28

APF Electronics 51

209

GR Electronics Ltd 271

202

Apparat 266

75

H & E Computronics 156

4

Apple Computer 13

95

H & E Computronics 157

76

Applied Computer Sys 132

304

Hampshire Design 322

240

Aristo Polks 294

128

Hardside211

10

Artec Electronics 24

62

D C Hayes Associates Inc 106

253

ASAP 302

141

D C Hayes Associates Inc 228

316

AT Enterprises 328

39

Houston Instruments 71

244

ATV Research 294

40

Houston Instruments 71

133

Automated Simulations 219

148

IBC 236

218

Avionic Enterprises (A.E.I.) 275

208

Inco Inc 271

63

Balcode Software Inc 107

Independent Business Sys 55

70

BASF 121

34

Industrial Micro Sys 63

271

Beckian 309

330

Infosoft Systems Inc 50

195

John Bell Engineering 263

189

INMAC259

Beta Computer Devices 253

15

Integral Data Systems, Inc 31

Bits Inc 285

190

Integrand 259

150

Bizcomp 238

426

Intel insert (between pp 16 R, 17)

The Business & Home

17

Intelligent Systems Corp 33

Computer Shows 207

287

Interactive Microware 320

BYTE Back Issues 285

170

Int'l Data Sciences 248

51

BYTE Books 89, 129

82

Inn Data Sys (IDS) 141

230

BYTE Books 279

41

Intertec 73

110

BYTE Conlerence 185-188

Ithaca Intersystems 9

165

C & S Electronics Mart 246

71

Ithaca Intersystems 122

9

California Computer Sys 20, 21

311

J & B Computer Products 328

266

California Data Corp 308

259

Jade 306, 307

322

California Digital 331

274

Jameco Electronics 314, 315

214

Cambridge Develop Labs 273

314

Jini Microsystems 328

CBS Records 10

67

Kemco Ltd 115

300

CCM Inc 322

185

Konan Corp 256

118

Central Data 197

Lifeboat 116, 117

18

Chatsworth Data 34

Lifeboat 243

123

Chrislin Industries 206

303

Logicon 322

152

Chrislin Industries 240

169

Lomas Data Products 247

Circle Computer Sales 282

312

M-Software 328

255

Cleveland Consumer Computers

145

Macrotronics 232

& Components 303

286

Macrotronics 320

196

Compas Microsystems 263

224

McClintock Corp 277

147

Complete Business Systems 235

Meas Sys & Controls 57

273

CompuMart 312, 313

Meas Sys & Controls 316

72

CompuMax 123

293

Med-Ford Software 320

56

CompuServe (microNET) 97

173

MICAH 249

"

CompuSystems 49

32

Micro Age Computer Stores 61

122

Computer Data Systems 205

87

Micro America 150

Computer Factory 133

89

Micro America 151

16

Computer Furniture & Access 32

101

Micro America 171

Computer Headware 254

113

Micro America 191

180

Computer Marketing Corp 253

164

Micro Applications Group

Computer Prof Books Club 231

(MAG) 246

280

Computer Service Center 316

237

Micro Architect 294

279

Computer Services 316

249

Micro Business World 299

294

Computer Shop Inc 320

329

Microcomputer Tech inc 266

260

Computer Shopper 308

277

Microcomputer Tech Inc. 316

86

Computer Specialties 149

38

MICRO DATA BASE

163

Computers Wholesale 246

SYSTEMS 69

12

Computex 26

136

Micromail 223

203

CompuView 267

261

Micro Mart 308

256

Concord Computer Components 304

80

Micro Mike's Inc 137

159

Coosol Inc 244

156

Micro Management Sys 242

22

Corvus Systems 41

Micro Pro Intl 131

220

Cover Craft 275

238

Microsette 294

179

CPU Shop 102

52

Microsoft 91

299

Cranial Labs 322

100

Microsoft (Cons Prod Div) 169

1

Cromemco 1, 2

45

Micro Source 81

192

CT MicroCOMPUTER, Inc 261

30

Microtek 59

Cybernetics Inc 248

229

Microware 278

236

DAR Sales 294

7

The Micro Works 18

321

Dal-Comp 329

49

Micro World 85

Data Access 233

171

Midwest Computer Periph 248

213

Data Discount Center 273

247

Mikos 298

228

Datadisk Systems 278

187

Mini Computer Suppliers 257

58

Data Management Labs 99

98

Mini Micro Mart 164, 165

131

Data-Safe Products Inc 214

105

Mini Micro Mart 179

153

The Datak Corp 241

142

Mini Micro Mart 229

295

Delta Products 321

305

Mini Micro Mart 323

175

DG Electronics 249

326

Morrow/Thinker Toys CV III

137

Dennison Kybe Corp 224

8

Mountain Hardware 19

265

Des-Mar Electronics 308

79

Mountain Hardware 136

106

Diablo (Div of Xerox) 181

19

MT MicroSYSTEMS 35

124

Digi Byte 80

296

Multi Business Comp Sys 322

194

Digital Graphic Systems 261

139

National Multiplex 226

221

Digital Marketing 276

National Small Comp Show 230

120

Digital Pathways 201

231

NCC (Personal Computing) 281

309

Digital Research: Comp 327

167

NEBS (New England Business

111

Digital Research Corp 189

Service Inc) 247

160

Discount Software Croup 245

88

NEECO 150

198

Dr Dobb's Journal 264

90

NEECO 151

155

Dynacomp 241

102

NEECO 171

288

Dynasoft Systems 320

114

NEECO 191

193

Ecosoft 261

115

Netronics 193

Electravalue Industrial 294

116

Netronics 193

284

Electrolabs317

121

Netronics 203

306

Electrolabs 324, 325

14

North Star 29

54

Electronic Control Tech 93

283

Northwest Computer Serv 316

126

Electronics Book Club 209

327

Ohio Scientific Instrument CV IV

245

Electronic Systems 295

46

OK Machine and Tool Corp 82

246

Electronic Systems 296, 297

85

OK Machine & Tool Corp 147

215

Escon 273

188

OK Machine & Tool 257

135

Essex Publishing 222

219

The Old Association 275

186

Excel 257

OnComputing 289

211

EXCOM 271

68

Orange Micro 118

Factory Direct Sales 252

74

Oregon Software 128

315

Falrcom 328

132

Osborne/McGraw-Hill 215

292

OSM Computer 320

24

Smoke Signal Broadcasting 45

Owens Associates 198

25

Smoke Signal (Dealers only) 45

262

Pacific Exchanges 308

48

Softagon Inc 84

289

Pacific Exchanges 320

112

Softech 190

328

Page Digital 330

13B

Softside 225

176

PAIA 251

151

The Software Exchange 239

250

Pan American Elect 300

234

Software Factory 284

(A Radio Shack Auth Sales Ctr)

264

The Software Farm 30B

127

PCD Systems Inc 210

310

The Software Review 328

290

PEEK (65) 320

217

Software Works 275

5

Per Com Data 15

308

Solid State Sales 326

37

Per Com Data 67

154

Sorrento Valley Assoc 241

43

Per Com Data 76 & 77

35

Southern Computer Sys Inc 64

97

Personal Computers 161

325

Southwest Tech Prod Corp C II

99

Personal Software 167

210

Spectrum Software 271

Phase One Systems 227

3

SSM 11

168

Pickles & Trout 247

166

The Stackworks 246

184

Potomac Micro Magic 255

282

Starburst Computer

55

Power One 95

Group Inc 316

285

Priority One 318, 319

130

Strategic Simulations 213

92

Prodigy 153

93

Structured Sys Group 154

119

Program Design Inc (PDI) 199

31

SubLOGIC 60

81

The Program Store 139

73

Summagraphics 125

84

QC Microsystems 145

298

Sunflex 322

21

QT Computer Sys Inc 39

254

Sunny International 302

272

QT Computer Sys Inc 310, 311

Supersoft 92

301

Ouadrus Associates 322

78

Supersoft 135

47

Quasar Data Products Inc 83

94

Supersoft 155

59

Quay Corp 101

206

Support Tech & Prod Inc 269

42

Quiet Designs Inc 75

11

Symtec 25

252

Quest 301

60

Sybex 103

91

R & K Enterprises 152

61

Synchro Sound 105

66

RACAL — Milgo 113

222

Synergetic Comp Prod 277

201

Racet Computes 265

108

Tarbell 183

258

Radio Hut 305

69

Tech Sys Consultants (TSC) 119

33

Raygam 62

64

Tec-Mar 108

96

RCA 159

13

TeleVideo Inc 27

77

RCA Solid State 134

278

Terminal Data 316

172

Reliable Comp Resources 248

57

Texas Electronics Instruments

275

Renaissance Sys Inc 316

(T.E.I.) 98

2

RITAM International 8

26

Texas Instruments 47

239

RLK Software 294

157

3-G Co 243

129

RNB Enterprises 212

23

3/M Company 42, 43

182

Robotics Age 255

Robert Tinney Graphics 17

225

S-100 277

317

TL Industries 328

263

S & A Data Sys 308

297

Torrey Pines Business Sys 322

149

Howard W Sams Co Inc 237

199

TransNet 265

177

Sara-Tech 251

United Software 245

223

SC Digital 277

241

Univair Inc 294

227

SCDP 278

36

Universal Data Sys 65

SCION CORP 5

207

US Robotics 269

65

Seattle Computer Prod 109

216

Vector Electronics 274

205

Selanar 269

20

Verbatim Corp 37

212

Michael Shrayer Software 273

302

Videx 322

Shopsmith 204

324

Vista Computer 334

Shugart 6, 7

270

VR Data 309

158

Sigma International 243

251

Wameco 300

183

Sigma International 255

Wang Labs 217

178

Sirius Systems 251

197

Western I/O 263

134

Small Business

Whitesmith's Ltd 127

Applications Inc 221

313

Winlek Corp 328

Smalt Business Sys Group 158

281

Worldwide Electronics 316

161

Ed Smith's Software Works 245

181

2S Systems 253

BO

MB

>rBox

BYTE's Ongoing Monitc

Article #

Page Article

Author

1

12 The Cassette Lives On, An

Alternative to Floppy-Disk Mass

Storage

Cook

2

20 A DC-to-DC Converter

Picco

3

22 I/O Expansion for the Radio ShackTRS-80, Part 1: Principles of Para lie

Ports

Ciarcia

4

44 KIM DOS, Using Your KIM-1 with a

Percom Floppy-Disk Drive

Swank

5

72 Interface a Floppy-Disk Drive to an

8080A-Based Computer

Hoeppner

6

104 A Graphics Text Editor for Music,

Part 2: Algorithms

Nelson

7

120 Using the Computer as a Musician's

Amanuensis, Part 2: Going from

i

Keyboard to Printed Score

Raskin

8

130 Comparing Floppy-Disk Drives by

Software Simulation

Nendza

9

196 Give Your Computer an Ear for

Names

Munnecke

10

202 The Club Computer Network

Kasser

11

214 The COSMAC Doodler

Duntemann

12

250 Error Checking and Correcting for

Your Computer

Walker

Bomb results on previous page

336 May 1980 © BYTE Publications Inc

There are twosides to our story.

Side One

The DISCUS 2+2 Quad-Density Hardware

Now you can use yourS-100 system to tackle bigjobs. Because the DISCUS™2+2 Quad-Density DiskSystem puts 1.2 megabytes offast-access memory on yourside for just $1545.00 complete.

With the DISCUS™ 2+2 Systemcomplete means complete.

You get a full-size (IBM-compatible 8") double-sided/double-density disk drive,

factory mounted in a cabinet withpower supply fully-buffered S-100single-board controller, and inter-connecting cables. All fullyassembled, system-tested andfully warranteed.You get the speed andefficiency of 1.2 megabyte-per-diskette memory...and you get it for 0.13$per byte.

Side Two

The DISCUS 2+2 Quad-Density Software

1.2 megabyte quad-density hard-ware is only one side of the story.The DISCUS™ 2+2 System priceincludes all the fully-interfaced,high-performance software youneed to take full advantage of yourquad capacity.

The system includes our exclusiveBASIC-V™ virtual disk BASIC, whichallows you to address your quad-density diskettes as easily as main memory. Theoperating system you get is the widely acceptedCP/M* 2.1. And you get our powerful DISK-ATEtext editor/assembler; The most advanced software

development tool available.

Micro-Soft BASIC 5.1 and Micro-Soft FORTRAN are available asoptions. Both run under CP/M* 2.1.Check out the full system price ofDISCUS™ 2+2 Quad against anyother floppy disk system at yourlocal computer store. At $1545.00,we think you'll take sides with^^^^^m DISCUS™ 2+2.

If your dealer doesn't carry THINKER TOYSproducts, write MORROW DESIGNS Inc., 5221Central, Richmond, CA 94804. Or call (415)524-21019-5 weekdays (Pacific Time).

9

MORROW DESIGNS 7 Thinker Toys

*CP/M is a trademark of Digital Research.

Circle 326 on inquiry card.

Step up to yournext computer.

\ZJ

fi':E3t:

STEPUPT0AC4PFROM OHIO SCIENTIFIC

You know about computers. In fact,you probably own one now. One thatyou might be thinking of expanding. Wehave a better idea. Take a giant stepinto the personal computing future withan amazing, new C4P from OhioScientific.

SPEED SEPARATES THECOMPUTERS FROM THE TOYS

The C4P MF has execution speed thatis twice as fast as Apple 11 orCommodore PET and over THREEtimes as fast as TRS-80. They aremany times faster than the recentlyintroduced flock of video game typecomputers. And, as if that weren't fastenough, the C4P nearly doubles itsspeed when equipped with the GToption.

Just look at the backpanel of the C4PMF.

All the 1/0 vou'll ever need'

SOUND

1—programmable tone generator

200 —20KHz1—8 bit companding digital to analog

converter for music and voice

output.

HUMAN INPUT EXPANSION

2—8 axis joystick interfaces2—10 key pad interfaces

HOME INTERFACE

1—AC-12 AC remote control interface

DISPLAY

32 x 64 with upper and lower case2048 Characters.256 x 512 effective Graphic Points16 Colors

SOFTWARE

Ohio Scientific offers a comprehensivelibrary of both systems andapplications software for the C4P.

The C4P is an outstanding premiumcomputer — years ahead of themarket. We know because there'snothing quite like it for the price,anywhere. And probably won't be for avery long time.

C4P*750

8K BASIC-in-ROM, 8K of static RAMand audio cassette interface. Can bedirectly expanded to 32K static RAMand two mini-floppy disks.

C4PMF*T795

All the features of the C4P plus realtime clock, home security systeminterface, modem interface, printerinterface, 16 parallel lines and anaccessory BUS.TheC4P MF startswith 24K RAM and a single mini-floppyand can be directly expanded to 48Kand two mini-floppies. Over 45 diskettesnow available including games,personal, business, educational andhome control applications programs aswell as a real time operating system,word processor and a data basemanagement system.

Computers come with keyboards and floppies where specifiedOther equipment shown is optional.

For literature and the name of your localdealer, CALL 1-800-321-6850 TOLL FREE.

1333 SOUTH CHILLICOTHE ROADAURORA, OH 44202 • [216] 8c■'! -5600

Apple II. Commodore- PET. TRS-80, and At.ir, BOOaro regiiComputer loo , Commodore Business Machioes Lid,, Rsdio

Circle 327 on inquiry card.