Byte Magazine Volume 05 Number 02 - Graph Theory

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BYTE February 1980

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2 BYTE February 1980

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m

In The Oueue

fi^TI February 1980 Volume 5, Number 2

Foreground

page 72

'■■—"

- v.

/'\ \

\

. V- V

y v

/

\

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y

18 A FIRST LOOK AT GRAPH THEORY APPLICATIONS by Michael Ashbrook and Helmut Zinn

If the use of graph theory raises a question, this article will supply an answer. The authors introduce the fundamental concepts of graph theory and two methods of directed-graph storage.

32 A COMPUTER-CONTROLLED WOOD STOVE by Steve Ciarcia

Steve Ciarcia shows how he uses his computer to monitor and control a Hydrostove— a wood stove that heats water piped through it.

72 A COMPUTER-CONTROLLED LIGHT DIMMER, Part 2: Implementation by

John H Gibson

Part 2 of this article shows how to construct the design that was presented in the January 1980 BYTE, using the Heathkit ET-3400 microprocessor trainer.

92 IMPLEMENTING DYNAMIC DATA STRUCTURES WITH BASIC FILES by Ted

Carter

Using linked lists to maintain sorted files is one way to deal with limited memory, large files, and additions and deletions to these files.

106 A FAST, MULTIBYTE BINARY TO BINARY-CODED-DECIMAL CONVERSION ROUTINE by Michael McQuade

This general-purpose algorithm performs these conversions and assembler programs for the 8080 processor.

192 A FINANCIAL ANALYSIS PROGRAM by John H Lehman

Most investors will agree that financial stability and success require an organized systematic means of assessing investments. The program written by John Lehman can output the typical information required for such a financial report.

202 ANOTHER PLOTTER TO TOY WITH, REVISITED: Design and Construction Details by Robert K Newcomb

Robert Newcomb tells how to construct and program the low-cost plotting system described by Peter Lucas in the February 1979 BYTE. Robert uses a KIM-1 and various electromechanical parts.

Background

page 14

58 SOLVING PROBLEMS INVOLVING VARIABLE TERRAIN, Part 1: A General

Algorithm by Scott T Jones

The method described by Scott Jones can be applied to a wide range of problems in business and industry as well as conflict simulations and games.

116 A QUAD TERMINAL INTERFACE by Stephen A Alpert

Building this interface solves the occasional problem of having one interface port and the need to use three or four peripherals.

128 COMPARISON OF SOME HIGH-LEVEL LANGUAGES by Robert A Morris

Some programming languages are more appropriate to a particular application than others. This comparison will help you choose the right language from the many possibilities.

176 BASIC FORMATTED OUTPUT by William D Roch

The feature provided here will give your BASIC package the control where a particular piece of information will appear on a line when you are performing input and output routines.

Nucleus

6 Editorial: The Seven Bridges of Konigsberg

14 Letters

69 BYTE News

82, 86 Programming Quickies: Gasuse; String Comparator for Horizon

88 Clubs and Newsletters 140, 146, 172, 174 Technical Forum: Some Example Plots; Introduction to Code Tightening; Mining the Skip Chain

for Extra Bytes of Code; Audio Meter for Your TRS-80; Algebraic Identities Are Not Numerical Identities 154 Event Queue 162, 208 BYTE's Bits 168, 208 BYTE's Bugs 188 Book Reviews 212 What's New?

255 Unclassified Ads

256 Reader Service, BOMB

February 1980 © BYTE Publications Inc

Publishers

Virginia Londoner, Gordon R Williamson Associate Publisher John E Hayes Assistant

Jill ECallihan

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Christopher P Morgan

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Richard S Shuford, Gregg Williams

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Bob Braisted

Editorial Assistants

Faith Ferry

New Products Editor

Clubs, Newsletters

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Drafting

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Production Director

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Copy Editors

Faith Hanson, Warren Williamson,

Robin M Moss, Anthony J Lockwood

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Ellen Bingham

Production Art

Wai Chiu Li, Christine Dixon,

Holly Carmen LaBossiere, Deborah Porter

Typographers

Cheryl A Hurd, Debe L Wheeler, Sherry McCarthy

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Patricia E Burgess

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Adv/Prod Coordinator

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Marketing Coordinator

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Circulation Manager

Gregory Spitztaden

Assistants

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Melanie Bertoni, Barbara Ellis

Dealer Sales

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Jacqueline Earnshaw

Traffic Department

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Controller

Daniel Rodrigues Assistant

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National Advertising Sales Representatives:

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4 February 1980 © BYTE Publications lnc

ON THE COVER

Topology is the theme of this month's cover painting, "The Seven Bridges of Konigsberg" by Robert Tinney. It is a fanciful representation of a classical, topological problem made famous by the Swiss mathematician Enter, and it has a more than passing resemblance to the works of the Sioiss artist M C Escher. The celebrated problem is discussed in detail by Carl Helmers in this month's editorial, and the painting is also loosely inspired by the theme article, "A First Look at Graph Theory Applications." by Ashbrook and Zinn. Sharp-eyed readers might spot a visual reference to another famous mathematical problem hidden in the cover.

Officers of McGraw-Hill Publications Company: Paul F. McPherson, President; Executive Vice Presidents: James E. Boddorf, Gene W. Simpson; Group Vice President: Daniel A. McMillan; Senior Vice President-Editorial: Ralph R. 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 subsidiary of McGraw-Hill, Inc. Address all mail except subscriptions to above address: phone (603) 924-9281. Address subscriptions, change of address, USPS Form 3579, and fulfillment questions to BYTE Subscriptions, PO Box 590, Martinsville NJ 08836. Second class postage paid at Peterborough NH 03458 and at additional mailing offices—USPS Publication No. 102410 (ISSN 0360-5280). Canadian second class registration number 9321. Subscriptions are $18 for one year, $32 for two years, and $46 for three years in the USA and its possessions. In Canada and Mexico, $20 for one year, $36 for two years, $52 for three years. $32 for one year air delivery to Europe. $32 surface delivery elsewhere. Air delivery to selected areas at additional rates upon request. Single copy price is $2.50 in the USA and its possessions, $2.95 in Canada and Mexico, $4.00 in Europe, and $4.50 elsewhere. Foreign subscriptions and sales should be remitted in United States funds drawn on a US bank. Printed in United States of America.

Address all editorial correspondence to the editor at the above address. Unacceptable manuscripts will be returned if accompanied by sufficient first class postage. Not responsible for lost manuscripts or photos. Opinions expressed by the authors are not necessarily those of BYTE. Entire contents copyright © 1980 by BYTE Publications Inc. All rights reserved. ,,i0,

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Editorial

The Seven Bridges of Konigsberg

by Carl Helmers

Shugart

Covers, like editorial themes, are sometimes drawn from interesting subjects intended as themes for an issue. But divergences can occur. This month, the nominal theme for the issue is the topic of graph theory. It takes only one article to suggest such a cover theme, and the article "A First Look at Graph Theory Applications " by Michael Ashbrook and Helmut Zinn provided the initial suggestion. But our actual cover is inspired by a historical problem in mathematics which led to the definition of a much broader field: topology.

This generalization occurred as a result of trying to find a nice neat visual image that fits the topic of graph theory. In order to concoct a cover idea on graph theory, the first step is to start searching around for some theme on a diagram of nodes and interconnecting segments which is not some hackneyed abstract pun. In order to construct a visual image for a cover, I needed to find some seminal problem with dramatic visual import. This problem must define and suggest the general field of endeavor. So, I proceeded to hunt around.

A good forest in which to hunt mathematical images is an excellent fourvolume set of books entitled The World of Mathematics, by James R Newman, published by Simon and Schuster in 1956, and still available at a cost of $39.95. On the covers of the four volumes we find the description "a small library of the literature of mathematics, from A'h-mose the Scribe to Albert Einstein, presented with commentaries and notes." These books present a selection of original papers by mathematicians, with introductions and commentary by the editor. As serious or recreational reading for those interested in mathematical subjects, I highly recommend it.

So, naturally, I turned to the index of Mr Newman's book. I knew that somewhere in that 2535-page work I might find some visual image with which artist Robert Tinney could work to create a cover. It did not take long to find the appropriate image. On pages 570 thru 599 we find Mr Newman's commentary on graph theory, which is really an illustrative subset of a much more general field, topology. Following three pages of editor's commentary, the two papers reproduced in this section of the book are Leonhard Euler's memoir "The Seven Bridges of Konigsberg" (1735) and a survey article "Topology," by Richard Courant and Herbert Robbins, taken from their book What Is Mathematics? (Oxford University Press, 1941). When I encountered the problem of the Seven Bridges of Konigsberg in the form of Euler's paper, I knew we had a cover image.

The problem is quite simply stated: a city, Konigsberg, is built on an island in the river Pregel (see figure 1). We wish to find out if it is possible to cross all seven bridges in an afternoon's walk without crossing any bridge more than once.

Figure 1: Map of the town of Konigsberg

in Prussia, reproduced from

Euler's paper on the subject,

first published in

1735. Within the

town there is an

island called

Kneiphof, labeled

A in the figure, around

which flows the river

Pregel. Seven bridges, labeled

a, b, c, d, e, f, and g, cross the a

two branches of the river. The various

land areas of the town are labeled A,

B, C, and D.

6 February 1980 © BYTE Publications In

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BYTE February 1980

What Euler did, in an eminently readable argument in his paper, is to prove that it is indeed not possible. He proves that the popular hobby of the Konigsberg folk of seeking that magic path could never succeed. In so doing, he helped to found the science of topology. According to Newman in his commentary on the paper,

The problem — to cross the seven bridges in a continuous walk without recrossing any of them — was regarded as a small amusement of the Konigsberg townsfolk. Euler, however, discovered an important scientific principle concealed in the puzzle. He presented his simple and ingenious solution to the Russian Academy at St Petersburg in 1735. His method was to replace the land areas by points and the bridges by lines connecting these points. The points are called vertices; a vertex is called odd or even according as the number of lines leading from it are odd or even. The entire configuration is a graph; the problem of crossing the bridges reduces to that of traversing the graph with one continous sweep of the pencil without lifting it from the paper. If the graph contains more than two odd vertices, it may be traversed in one journey but it is not possible to return to the starting point. The general principle is that if the graph contains 2n odd vertices where n is any integer, it will require exactly n distinct journeys to traverse it. . . .

Thus began a "vast and intricate theory [topologyl," still young and growing, yet already one of the great forces of modern mathematics.

Now we had the general outline of the image. Fine details remained to be worked out with Robert. Now, Robert Tinney and I know of a number of artists that we regard as extremely interesting in general style and subject mater. There are, for example, the direct and conscious influences of Maxfield Parrish and Norman Rockwell on Robert's style of painting as often seen in covers of BYTE. However, we have of late been getting immersed in the fascinating art of M C Escher. Part of this fascination has been lying dormant since Martin Gardner's series of articles on Escher and tesselations of the plane in Scientific American (see his "Mathematical Games" column in the July 1975 (page 112), August 1975 (page 112), December 1975 (page 116), January 1977 (page 110), and June 1978 (page 18) issues). The fascination is of course greatly rekindled by the recent publication of the book Godel, Escher, Bach by computer scientist Douglas R Hofstadter.

So, given the theme of the seven bridges of Konigsberg, the added input of a recursive-programming computerscience pun clearly evident in the image, and a fascination with Escher's style, Robert chose to produce a cover image inspired by the art of Escher. The result is what you see.B

In Next Month's BYTE

The March 1980 BYTE will be devoted to "Computers and the Sciences." The theme articles will cover diverse topics such as "Electron Behavior in Chemical Bonds," "Electronic Planimetry," "Chemistry Program for the Apple Computer," and a "Derailleur Speed-Calculation Program."

An Update on Direct Cursor Addressing and UCSD Pascal

In last month's editorial on the Apple Pascal system, I made some comments about difficulties in getting the UCSD System to emit the cursor addressing character of my Computer Peripherals Corp "COPS-10" terminal. This terminal requires the sequence of "controlP, <Y+32>, <X+32>"to directly address a given location on the screen.

It turns out that the UCSD Pascal System (not just the Apple II version) gobbles "control-P" characters on output, whether through use of WRITE, WRITELN or even UNITWRITE. Naturally, it became a challenge to find out how to emit a controUP.

So, trying brute force as a first method of solution, I wrote an assembly language program using the UCSD Pascal System's 6502 assembler. This assembly language program simply set up the parameter's for the routine "SHOUT" within the Apple II serial card's read-only memory, then called that routine to emit the control-P character. I proved it worked by writing a Pascal GOTOXY procedure and test program.

The UCSD Assembler proved more than adequate for my purposes, in its 6502-oriented version running on the Apple. A most useful feature is its macroinstruction facility with conditional assembly. The Apple documentation of the UCSD System includes examples of assembly language interfaces which proved to be quite a helpful model. There was one convention that I had to worry about for a few assemblies. This was the fact that the assembler only allows hexadecimal integer constants. The assembler also demands uppercase only for tokens, although lowercase works fine in comments.

Of course, the version of the Pascal GOTOXY that used this assembly language procedure had to have an external procedure definition. This presented no problem when compiling without any special compiler options. But the manual points out (and experience confirms) that the "[$U—)" option must be active when compiling the code file that will be linked into the system by BINDER. Every time I try to compile with the required {$U—} compiler toggle, I get a Pascal syntax error §183, "External declaration not allowed at this nesting level." This was in spite of the fact that the "PROCEDURE CTRLP3; EXTERNAL;" sequence is at the outer (PROGRAM) level of nesting.

I tried everything I could think of: linking before BINDER, not linking, using it with the [$U] toggle and without, etc, etc. I even recalled the existence of a magical UCSD Pascal compiler toggle "{$T + \", which is required for compilation of super-large systems programs. When used with the [$U~] option, I could get the program to compile and link with the assembly language program—but then BINDER would not accept it. Clearly it was all to no avail. Would I be stuck with the GOTOXY cursor kludge of

<home><LF>. . .<LF><HT>. . .<HT>

forever?

8 February 1980 © BYTE Publications Inc

Circle 3 on inquiry card.

At Intersystems, "dump" is an instruction.

Not a way of life.

[Or, when you're ready for IEEE S-KX), will your computer be ready for you?]

We're about to be gadflies again.

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607-257-0190/TWX: 510 255 4346

Well, impossible problems lead to new solutions when frustrations get high enough. One solution would of course be a new terminal that had the necessary cursor control keys (the up/down/left/right arrows) but used a different direct addressing sequence.

On the day I solved the problem, I was talking with Cameron Jones about getting the UCSD Pascal System version for my New England Digital Synclavier music synthesizer. (Cameron Jones, Syndey Alonzo, and Jon Appleton are the co-inventors of the Synclavier.) As the Synclavier and its ABLE/60 computer comes delivered, its native language is XPL. So implementing a UCSD Pascal system becomes a problem of implementing the core interpreter in XPL.

As I was talking on the phone with Cameron, I finally realized what was wrong. The cursor addressing character of my terminal is an ASCII DLE character which is also known as control-P when emitted from a keyboard. And the UCSD System will always eat control-P characters, since this is the spacescompression escape character of ".TEXT" files! Cameron pointed out that the specification of the UCSD Pascal UNITWRITE routine is that it will do spaces decompression.

So I had to have a character that looks like a control-P to the terminal but not like a control-P to UCSD Pascal. This character is of course a character with the integer value 144. Its value is obtained by turning on the high-order bit in an 8-bit character by adding 128 to the control-P character code's value of 16. While the Pascal program's character data value are 8 bits, the terminal only looks at the low-order 7 bits. Thus, if the low-order looks like a control-P, turning on the high-order bit will keep Pascal from thinking it really is a DLE while allowing the terminal to think it is.

Everything else immediately simplified and fell in place. Listing 1 shows the final version of the GOTOXY procedure, which now emits an 8-bit

pseudo- control-P character that gets interpreted by the terminal as a 7-bit control-P character.

Of course, by getting frustrated by this problem, I explored the use of assembly language features of the UCSD System. I learned how to link successfully to assembly language programs, use the macroassembler that comes with the system, and unwind parameters from the Pascal stack in assembly language programs. I will probably never again use an assembly language program with a Pascal program. But if I need to for some reason of speed, I now know it is possible. This short note and this month's editorial were the first texts I edited using the new version of GOTOXY; the results are quite an improvement — / am no longer limited by rather artificial delays required by last month's cursor addressing kludge.

Listing 1:

!»SU-«) PROGRAH GOXYi

C the final version of the GOTOXY procedural used with Apple Pascal

C and the Computer Peripherals Corporation COPS-10 terminal. The

C ASCII (7 bit) seouencet

C <ctrl P> <Y+32> <X+32>

C causes direct cursor addressing>

PROCEDURE FCOTOXY!x-a:<is»y_axist INTEGER)!

( COPS 10 - GOTOXY J

CONST

eonlrol_P « 144 Chiah order bit onr but no effect 16+1203) VAR

x.w : integer;

abate 1 PACKED ARRBYCO..0] OF CN6RI

BEGIN

! ... hou do we send a "control P" when the Pascal UNITURITE will ) C sobble it because it thinKs that it is spaces compression char- ) C acter? Uellf recodnlze that the terminal only pays atten- }

C tion to 7 low order bits* Thus if we send a a control P with ) f the hiah order bit on» then UNITURITE will say "aha that is not 3 ( a control p" and the terminal will say "ah3 that is a control P") abyteCO] := CHR( Control-P); UNITURITE! 1>abyle.l.f1 )i

:: 1= >:_axis + 32; y := y-axis + 32; IF >: > ill THEN X := 111! IF ;: < 32 THEN >: 1= 32; IF y > 55 THEN y != S5; IF y < 32 THEN y 1= 32: abyteCO) := CHR(y); UNITURITE! l.abyte.l.tl1! abyteCO) i= CHR< >:)! UNITURITE! lrabyle.lnl> END Csotoxy}!

BEGIN (# DUMMY MAIN *)

END.

!*!U-*>

Clll = 7? + 32)

On Eclipses, Next Month's Editorial and the West Coast Computer Faire. . .

As you read this February 1980 issue of BYTE, I will be embarking on a journey to make the technological fantasy of last July's editorial ("Computers and Eclipses," page 8) real. In the March 1980 editorial, I plan to describe some of the details of the computer system which will control my Nikon F2A camera in automatic photography of the 1980 solar eclipse from Kenya in Africa.

I am scheduled to leave for Kenya on February 6, 1980, joining a small expedition of solar physics experimenters organized by Norm Whyte of Monte Rio, California. Norm is performing experiments involving a custom designed camera under direct computer control of an Apple II.

The only uncertainty is what the weather will be like at our observation site on the morning of February 16, 1980. Whatever the weather, readers who are going to the West Coast Computer Faire in San Francisco in March 1980 will be able to see the results in a talk

entitled "Microcomputers in Africa: A Travelogue of The 1980 Eclipse."

Norm and I will be presenting this talk as part of the technical program. It will feature slides made during the trip showing the setup and equipment (as well as scenery) and—weather permitting—slides of the eclipse itself. . . .CH

Articles Policy

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

Articles which are accepted are purchased with a rate of up to $50 per magazine page, based on technical quality and suitability for BYTE's readership. Each month, the authors of the two leading articles in the reader poll (BYTE's Ongoing Monitor Box or "BOMB") are presented with bonus checks of $100 and $50. Unsolicited materials should be accompanied by full name and address, as well as return postage.

10 February 1980 © BYTE Publications Inc

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BYTE February 1980

13

Letters

8086 Software Needed

I am interested in designing systems based on 8086 processors. Does anyone have some useful systems software to sell? I am particularly interested in filehandling software and operating systems in general. I am interested in purchasing source listings and I am prepared to visit software houses on my next trip to the US.

Martin Healey

Computer Systems Consultant

9 Ennerdale Close

Penylan, Cardiff CF2 5NZ

GREAT BRITAIN

Battle of the Buses

In the October 1979 "BYTE News," page 107, Sol Libes contends, in an item about the S-100 bus, that "those who wish to have a machine capable of get

ting the maximum benefits of microprocessors must go the S-100 route." While Mr Libes was comparing the S-100 bus to all-in-one systems, such as the TRS-80 and PET, his statement leaves out a number of computer systems with as much capability as S-100 systems, perhaps more in some cases. For example, the SwTPC S/09 and the Ohio Scientific Challenger III Series are two systems that come to mind. The former uses a 6809 processor with the SS-50 bus (see October BYTE, inside front cover), and the latter uses 6800, 6502, and Z80 processors and apparently OSI's own bus (see back cover, same issue). Both of these systems have a 20-bit address bus for large memories. SwTPC and several other companies make SS-50 bus systems using the 6800. Other non-S-100 bus systems include the Heath H8 and Hll. Any of these systems, and probably others that I have left out, can be as good for serious personal computer

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users as any S-100 bus computer. The S-100 bus is not the only possible route.

Mr Libes also writes that "the S-100 bus is not processor dependent." This statement is debatable, in spite of the existence of S-100 boards for a number of microprocessors. Several signals on the S-100 bus are generated ONLY by the 8080. Any other processor must be "bent" into generating (or responding to) these 8080-specific signals.

Personal computing could use a truly processor-independent bus. I feel that the S-100 bus will not be totally satisfactory in this role.

The mention of specific products in this letter does not necessarily constitute endorsement of these products. My point is simply that there are other buses besides the S-100, and that systems using these other buses can be just as capable as S-100 systems.

Jim Howell

5472 Playa Del Rey

San Jose CA 95123

Author Libes replies:

Thank you for your letter regarding my comments on S-100 systems in the October BYTE News column. Despite the views expressed in your letter, I still stand by my view that "those who wish to have a machine capable of getting maximum benefits of microprocessors must go the S-100 route." I agree with you that SS-50 and OSI Challenger 111 systems offer more power than integrated systems such as the TRS-80, Apple and PET. However, they still leave much to be desired compared to S-100. 1 will explain shortly.

Further, I also stand by my statement that "the S-100 bus is not processor dependent." The fact is that presently there are manufacturers selling six different 8-bit processor boards (8080, 8085, Z80, 6502, 6800 and 6809) and five different 16-bit processor boards (9900, LSl-11, 8086, Z8000 and Pascal Microengine) for S-100 systems. This means that eleven microprocessors have already been interfaced to the S-100. I do not know of any other system with this processor independence. Many of these microprocessors could not even be interfaced to buses such as the SS-50 or OSI without sacrificing performance.

When it comes to maximum power and flexibility the S-100 offers the following advantages over all other systems:

• More software available. There are several times more languages, operating systems and applications packages for S-100 systems than for any other system.

14 February 1980 © BYTE Publications Inc

Circle 6 on inquiry card.

WHY WE'RE NUMBER

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your copy today.

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BYTE February 1980 15

• There are currently close to two dozen different manufacturers of S-100 mainframes and about fifty manufacturers of over 400 S-100 plug-in boards. This is many times more than for any other system.

• There is greater computer power capability with S-100. What other system has direct addressing of up to 16 megabytes of memory (24 address lines) and 64 K input/output ports (16 address lines), up to eleven vectored interrupt lines, up to sixteen masters on the bus (with priority), up to twenty-three plug-in slots on the motherboard, up to 10 MHz clock on the bus, plug-in operator front panel, and more.

• The S-100 bus is now standardized by the Institute of Electrical and Electronic Engineers (IEEE) assuring conformance among manufacturers.

Regarding your reference to the H8 bus, note that Heath has discontinued production of this unit. Besides, it was dedicated exclusively to the 8080 and therefore was destined to an early death. The Heath Hll is essentially the same as and uses the same bus specifications as a Digital Equipment Corp LSTll. Few other firms support the LSTll with products within the price range of the

typical hobbyist. The hardware and software facilities, compared to the S-100, are limited and expensive.

Again, thank you for reading my column and I welcome any further comments you wish to make regarding my opinions.

Sol Libes

Pi in the Sky

As I get older, I forget more and more often that the "tricks" I sometimes use may not be common knowledge. I have recently come across several short programs that evaluate % to five or six decimal places. These are good programs, and I salute their authors. I, however, use the shortest of all programs for it and would like to pass it on. It gives an approximate answer that is in error by 27 parts in 100 million. Since this is well within the allowable . error of most computers, I use it without hesitation in all computer programming expressions.

Here goes. To enter ir accurate to six decimal places, write in its place 1/(113/355). That's all there is to it! The value of that expression is 3.14159292, while 7T is 3.14159265 ....

This little gem was taught to me for use on the slide rule, back during the 1940s. I pulled it out of my memoirs recently when I got my first microcomputer.

Please note that the denominator is easily remembered as the first three odd integers, doubled. The order of their appearance is obvious.

Emory W Sprenkle Jr POB 542 (53 Allen Rd) Billerica MA 01821

Keep Telling It Like It Is . . .

Thank you for the November editorial regarding pseudoscience and biorhythms in particular. It was certainly refreshing to have a hobbyist magazine of BYTE's reputation so clearly delineate between harmless biorhythm algorithms for the sake of computing recreation and the unscientific foundations of biorhythmic theory. Too many supposedly educated and intelligent people seem to have fallen into the "computer generated, therefore true . . ." trap you described. Perhaps you have caused some of them to critically examine the unsupportable premises of biorhythmic theory. Now if I could just get the campus radio station to stop broadcasting horoscopes . . .

Thomas Dolash Assistant Professor of Physics Physics and Engineering Dept Vincennes University Vincennes IN 47591

Good Humor Needed

I have found your magazine to be very educational and of excellent quality. I look forward to getting the new issue each month. However, I have a suggestion that I think might make your magazine even better and would be enjoyed by all your readers. Why not add a "Jokes & Riddles" column and a comic strip or two, and maybe a few "one-framers"7 I realize that your magazine tries to present a serious approach, but I think that this addition would be a plus, and a bit of humor would make it more fun for everyone. So how about it?

William P Carlson

Rosewood Cir

North Syracuse NY 13212

You would not believe the number of unsolicited cartoons we get that are anchored in the dark ages of computing prior to personal computing.

The problem is finding cartoon and humor generators who also understand the current era in computing. . . .CH ■

16 February 1980 © BYTE Publications Inc

clearly readable printouts clearly remarkable price

The $625* Heathkit H14 Printer. You'll pay hundreds more for a printer with its features.

Where else can you buy a microprocessorbased printer with the H14's features and copy quality for under a thousand dollars?

The Heathkit H14 prints up to 165 characters per second, one full line every two seconds.

5x7 dot matrix and finest quality impact printhead give you clear, easy-to-read images.

All functions are microprocessor-controlled for reliable performance and more efficient use of your computer.

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//

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Price includes connecting cables, paper rack and ribbon. Just add paper and you're ready to run. And service on the H14 is close by at any of 55 Heathkit Electronic Centers throughout the U.S. Complete details on the remarkable H14 are in the newest, free Heathkit Catalog. Send for yours today or pick one up at your Heathkit Electronic Center.

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home, work or pleasure — all at build-it-yourself savings. Send for yours today or pick one up at your Heathkit Electronic Centert where Heathkit Products are displayed, sold and serviced. See your white pages for center nearest you.

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Circle 8 on Inquiry card.

BYTE February 1980 17

A First Look at Graph Theory Applications

What do the following problems have in common?

• Finding the shortest route between two particular cities on a complicated road map.

• Finding the shortest route between any two cities on a road map.

• Selecting a set of roads that connects all the cities on your map and has less total mileage than any other such set.

• Calculating the maximum amount of liquid that can flow through a system of interconnected pipelines per unit of time.

These four real-life problems can be interpreted in terms of graph theory and can be solved by remarkably simple and efficient programs. The problems belong to a much larger category of operationsresearch problems; these were selected as examples because of their comparative simplicity. Algorithms for solving such problems along with the necessary background for understanding them will be examined.

While our terminology follows that of Narsingh Deo, our programs are quite different from his. If you become interested in solving more graph-theoretic problems on your own, you will find his book a stimulating introduction. (See Graph Theory with Applications to

Michael Ashbrook

Helmut Zinn

Wilhelm Epstein Str 27

6000 Frankfurt am Main 50

WEST GERMANY (BRD)

Engineering and Computer Science by Narsingh Deo, Prentice-Hall, Inc, 1974.)

Fundamental Technology and Concepts

A graph consists of a set of vertices (singular: vertex) and a set of edges that connect the vertices. In the previous examples the cities are the vertices and the roads are the edges. In drawings and diagrams the vertices of a graph are shown as dots or as tiny circles; the edges are shown as lines. A vertex and an edge are said to be incident if they touch. This relation of being incident holds the graph together.

A digraph (short for directed graph) consists of a set of vertices and a set of directed edges. Real-life examples of digraphs include systems of canals in which the water flows from point to point only in the downhill direction, electric networks in which the current flows only in one direction, and systems of one-way streets. The vertex from which a directed edge starts is called the initial vertex of the edge; that would be the point at the higher end of a canal. The vertex at which a directed edge ends is called the terminal vertex of the edge; that would be the point at the lower end of the canal.

Remember that each edge is incident (touches) with exactly two ver

tices, therefore every directed edge has exactly one initial and exactly one terminal vertex. A vertex can be incident with several directed edges, therefore the same vertex can be the initial vertex of one edge and the terminal vertex of another edge. See figure 1 for an example of a digraph.

Unless explicitly stated, all graphs and digraphs that are discussed are in one piece. That is to say, that for any two vertices there is at least one way to travel back and forth between them along the edges of the graph. Graphs (both directed and undirected) with this property are said to be connected. Disconnected digraphs are not discussed in this context because they can be treated as a set of connected digraphs.

For a similar reason, this article will concentrate on digraphs. A graph can usually be replaced by a digraph with the same set of vertices and exactly two directed edges, going in opposite directions, for every undirected edge of the original graph.

There are many ways to represent a digraph in a computer. Each method

About the Authors

Michael Ashbrook became interested in operations research after first studying mathematics. Helmut Zinn became involved with small computers through his work in electron]echanical engineering. Both collaborate at the Technische Hochschule in Darmstadt.

18 February 1980 © BYTE Publications Inc

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Figure 1: Example of a digraph (directed graph) directed edges.

that has seven vertices and twelve

has its advantages and its drawbacks; each has its applications. The two basic methods used to encode a digraph will now be discussed.

A Matrix Called DIGRAPH

Consider a digraph containing a certain number of vertices nr. The n, vertices of this digraph are represented by the natural numbers from 1 to nv. The edges of the digraph are represented by the entries of an nv by h„ matrix called DIGRAPH. If the digraph has a directed edge from the vertex j to the vertex /, then the entry

DIGRAPHS /) of matrix DIGRAPH that is in the i-th row and the ;'-th column has a nonzero value, DIGRAPHS ;)*0. If there is no edge from vertex i to vertex ;', the matrix entry DIGRAPH(/, /) is 0.

The matrix DIGRAPH can be used to store additional information about the digraph. If DIGRAPH is the mathematical model of a road map, the nonzero entries can be used to represent the distance from city i to city ;'. If you need to store no more data about an edge than the two vertices i, j which it connects, then the

TURN-ON!

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REMOTE CONTROLLER BOARD

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A directed graph (digraph) consists of a set of vertices and a set of directed edges.

hi ii i mi in i in i ii mi mi mi ii ii i hi imiiii minium inn mum

presence of the edge in the digraph is usually indicated by setting DIGRAPHS /) = l.

The matrix DIGRAPH is best suited for small-scale applications which involve no more than roughly fifty vertices. A digraph with n„ vertices, can be stored as a matrix that requires (nv)2 storage locations.

Disadvantages of Matrix Storage

In large-scale applications involving several hundred vertices, the matrix DIGRAPH often becomes sparse (or sparsely populated). The proportion of entries that are equal to zero increases. This happens because the real-life structures that are being stored as digraphs have relatively few edges compared to the number of edges which they could have.

Every town in the United States could be connected with all of the other towns by a direct road. As a practical matter, however, any given town is linked directly to only a few neighboring communities. Therefore, the DIGRAPH matrix of the total road system consists almost entirely of zeroes that mean nothing but the absence of a direct road between most combinations of two given towns. This matrix is very large and cannot be stored efficiently.

Increasing Storage Efficiency

In order to solve large-scale problems using a limited amount of storage space, a more efficient way of storing digraphs is necessary. Space should not be wasted on 0s that represent nonexistent edges.

As before, the n, vertices of the digraph are represented by the numbers 1 to nv. The edges are listed as pairs of numbers; the edge from vertex i to vertex ; is shown as the pair (/, /).

Suppose the digraph has a certain number of edges, nc, then these edges can be expressed as an ne-by-2 array called EDGE. Each row (i, /) of the EDGE array specifies one edge; the first entry i stands for the edge's initial vertex i, and the second entry j stands for the terminal vertex ;' of the

20 February 1980 © BYTE Publications lnc

Circle 10 on inquiry card.

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BYTE February 1980 21

VERTEX

EDGE

2 u- u

POINTER

» END OF CHAIN

END OF CHAIN

Figure 2: Portion of a digraph as represented by the list-oriented data structure. The arrows connecting the entries in the three lists {2-hy-2 arrays) show the logical connections in storage that represent the structure of the digraph. The arrows can be read as "points to."

In the list EDGE, after the identification number of the edge, two numbers that specify the initial and terminal vertices of that edge are found. For example, edge 3 has initial vertex 30 and terminal vertex 34.

In the list POINTER, each edge number has associated with it two other numbers that refer to positions of edges in the list EDGE (not in the digraph itself). The initial pointer of an edge refers to the last edge preceding the current edge that has the same initial vertex as the current edge. For example, the fourth entry in the POINTER list shown here points to the entry 3 in the EDGE list, showing that edge 4 has the same initial vertex as edge 3. The terminal pointer of an edge refers to the last edge preceding the current edge that has the same terminal vertex as the current edge.

In the list VERTEX, for each vertex in the digraph, there is an entry that tells the number of the last row of EDGE in which the current vertex appears as the initial vertex. There is also an entry that tells the number of the last row in the EDGE list in which the current vertex appears as a terminal vertex. For example, observe that the last edge with initial vertex 30 is edge 5; the last edge in EDGE with terminal vertex 30 is edge 2.

edge. If there is more information to be stored concerning the edges, then columns can be added to EDGE.

For the sparse digraphs that are being considered, the amount of storage space needed for EDGE is /c??„ rather than nv2; where k is the average number of edges per vertex in a given digraph.

The price for this significant saving in space is an increase in access time. To find all the edges incident with a vertex i in DIGRAPH, simply scan the ;'-th row and the ;'-th column of DIGRAPH. To find all the edges incident with vertex ; in EDGE, scanning the entire list is necessary. Since all of

the programs rely heavily on finding the edges that are incident with a given vertex, it pays to trade a little storage space for a reduction in access time.

To cut down on the access time, add a column of initial pointers and a column of terminal pointers to EDGE. You can spare yourself needless confusion if you always remember that these pointers refer to the positions of edges in the list EDGE and not in the digraph itself.

The initial pointer of a particular edge (i, j) refers to the last edge preceding the current edge (i, j) in EDGE that has the same initial vertex

i as (/, /), If (;', ;') is the first edge in EDGE that has the initial vertex i, then the initial pointer of (;', /) has the value zero.

The terminal pointer refers to the last edge preceding (£, /) in EDGE which has the same terminal vertex / as (t, /). If (/', /) is the first edge in EDGE with the terminal vertex /, then its terminal pointer has the value zero.

In order to reduce the access time further, establish a list called VERTEX in the form of a 2-by-n, array. The i-th row of VERTEX stands for the z'-th vertex of the digraph. The value of VERTEX(i, 1) is the number of the last row of EDGE in which i appears as the initial vertex. The value of VERTEX(i, 2) is the number of the last row in EDGE in which i appears as a terminal vertex.

22 February 1980 © BYTE Publications Inc

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BYTE February 1980 23

30 40 50 60 70 80 90 100 slUMBER OF VERTICES (nu)

Figure 3: Graph showing storage space requirements (st) of a digraph plotted as a function st(nj of the number of vertices (nj in a given digraph. It should be assumed that four bytes are required to store a decimal number.

The upper curve (black) shows the function st(nj when you use the method of storing your digraph representation in the matrix DIGRAPH.

Storage requirements of the list-oriented storage scheme vary according to the number of edges (nj. The equation is st(n„,ne) = 2nv+ 4ne. If the digraph has some constant k times as many edges as it has vertices (represented by the equation n,: = knj, then the equation of storage space becomes

st(nj = 2n„ + 4knv = (4k + 2)n„

The curve for the case k—3is shown in red (when there are three times as many edges as vertices), and the curve for k = 5 is shown in blue.

One fact illustrated by this diagram is that the list-storage approach is more efficient in use of storage space than the matrix approach so long as the digraph being stored has few edges compared to the number of edges that it could have (a sparsely populated lor just sparse] digraph). In terms of the equations here, sparseness means that k is much smaller than nv. The list-oriented storage method becomes relatively more efficient than matrix storage as digraphs become more sparse.

Listing 1: The digraph input and concatenation program in BASIC. This program was developed on an Exidy Sorcerer computer system.

Real-life structures produce digraphs that have relatively few edges. iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii

The list-oriented digraph representation is illustrated in figure 2.

Searching the Lists

Suppose you want to find those edges that have i as their initial vertex. Look at VERTEX(/, 1); if its value is zero, there are no such edges in the digraph. If its value is some nonzero value x, the first such edge is found in the Jt-th row of EDGE. If the value of the edge's initial pointer, PTR(x, 1), is zero, there are no more such edges in the digraph. (POINTER is a reserved word in our BASIC interpreter, so we have to use the abbreviation PTR.) If PTR(x, 1) equals some nonzero value y, the next such edge is found in the y-th row of EDGE and the new pointer ,is found in PTR(y, 1).

Continue to follow the pointers from edge to edge until a pointer with the value zero is found, which tells you that you have now found all the edges that have i as their initial vertex. If you substitute the value 2 wherever 1 occurs in the preceding paragraph, then there is an adequate explanation of the systematic search for all edges that have i as their terminal vertex.

The same scheme that has been

10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360 370 380 390 400 410 420 430 440 450 460 470 480 490

DIGRAPH INPUT AND CONCATENATION

COPYRIGHT 79/4 BY

MICHAEL ASHBROOK & HELMUT ZINN

FRANKFURT AM MAIN

REM REM REM REM REM REM REM REM REM *■««""*••""*........»........■....<.......*«.

REM READ AND LINK EDGE LIST

INPUT "NUMBER OF VERTICES"; NV

INPUT "NUMBER OF EDGES "; NE

DIM VERTEX(NV, 2)

REM VERTEX(V, 1) = EDGE WITH V AS INITIAL VERTEX

REM VERTEX(V, 2) = EDGE WITH V AS TERMINAL VERTEX

DIM EDGE(NE, 2), PTR(NE, 2)

REM EDGE(E, 1) = INITIAL VERTEX OF EDGE E

REM EDGE(E, 2) = TERMINAL VERTEX OF EDGE E

REM PTR(E, 1) = NEXT EDGE WITH THE SAME INITIAL VERTEX

REM PTR(E, 2) = NEXT EDGE WITH THE SAME TERMINAL VERTEX

FOR E = 1 TO NE

PRINT E; "EDGE (INITIAL VERTEX, TERMINAL VERTEX) ";

INPUT EDGE(E, 1), EDGE(E, 2)

NEXT E

REM SETTING UP THE POINTERS

REM L = 1 IMPLIES INITIAL POINTER OR VERTEX

REM L =2 IMPLIES TERMINAL POINTER OR VERTEX

FOR L = 1 TO 2

FOR E = 1 TO NE

V = EDGE(E, L)

IF VERTEX(V, L)=0THEN PTR(E, L) = 0: GOTO 330

PTR(E, L) = VERTEX(V, L)

VERTEX(V, L) = E

NEXT E

NEXT L

PRINT

PRINT " VERTEX LIST";

PRINT TAB(20); "EDGE LIST";

PRINT TAB(40); "POINTER LIST"

N = NV: IF NV<NE THEN N = NE

FOR I = 1 TO N

IF I>NV THEN GOTO 440

PRINT I;VERTEX(I, 1);VERTEX(I, 2);

IF I>NE THEN GOTO 470

PRINT TAB(20);I;EDGE(I, 1);EDGE(I, 2);

PRINT TAB(40);I;PTR(I, 1);PRT(I, 2);

PRINT

NEXT I

END

24 February 1980 © BYTE Publications Inc

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Circle 13 on inquiry card.

BYTE February 1980 25

Listing 2: A sample execution of the program of listing 1 using data from figure 1. An interpretation of the output is given in figure 2.

RUN

NUMBER

NUMBER

1 EDGE

2 EDGE

3 EDGE

4 EDGE

5 EDGE

6 EDGE

7 EDGE

8 EDGE

9 EDGE

10 EDGE

11 EDGE

12 EDGE

OF VERTICES? 7 OF EDGES ? 12 (INITIAL VERTEX, (INITIAL VERTEX, (INITIAL VERTEX, (INITIAL VERTEX, (INITIAL VERTEX, (INITIAL VERTEX, (INITIAL VERTEX, (INITIAL VERTEX, (INITIAL VERTEX, (INITIAL VERTEX, (INITIAL VERTEX, (INITIAL VERTEX,

TERMINAL TERMINAL TERMINAL TERMINAL TERMINAL TERMINAL TERMINAL TERMINAL TERMINAL TERMINAL TERMINAL TERMINAL

VERTEX) VERTEX) VERTEX) VERTEX) VERTEX) VERTEX) VERTEX) VERTEX) VERTEX) VERTEX) VERTEX) VERTEX)

1,2 1,3 2,3 2,4 2,5 3,2 3,4 4,6 5,4 5,7 6,3 6,7

VERTEX LIST

1 2 0

2 5 6

3 7 11

4 8 9

5 10 5

6 12 8

7 0 12

EDGE LIST

2

3

4

5

6

7

8

9

10

11

12

POINTER LIST

1

0

0

2

1

0

3

0

2

4

3

0

5

4

0

6

0

1

7

6

4

8

0

0

9

0

7

10

9

0

11

0

3

12

11

10

READY

START (LINE 100)

INPUT NUMBER OF VERTICES (NV) (LINE 110) NUMBER OF EDGES (NE)

DECLARE VARIABLE Dl MENSIONS ( LINE 130) VERTEX (NV,2) EDGE (NE,2) PTR (NE.2)

INPUT EDGE SPECIFICATIONS (LINE 210)

(INITIAL VERTEX,TERMINAL VERTEX)

DO WHILE L VARIES FROM 1 TO 2 (LINE 250) LINK INITIAL POINTERS (L=l) AND LINKTERMINAL POINTERS (L=2)

V = EDGE IE.L)

V-- INITIAL OR TERMINAL VERTEX OF EDGE E

IF VERTEX (f.Ll'O (LINE 310)

SET POINTER TO CHAIN END

PTR (E,L I = 0

SET POINTER TO THE NEXT PREVIOUS EDGE WITH THE SAME INITIAL (OR TERMINAL) VERTEX PTR <E,L I ' VERTEX IV,L I

VERTEX !V,L) = E

CONCATENATE EDGE WITH VERTEX LIST

UNTIL E = NE (FOR ALL EDGES FROM 1 TO NE )

OUTPUT VERTEX, EDGE,PTR (PRINT ALL LISTSMLINE 360)

STOP (LINE 490)

Figure 4: A Nassi-Schneiderman chart showing the algorithm used by the BASIC program of listing 1. Nassi-Schneiderman charts are a system of stylized flowcharts that are designed for use with structured programming techniques. The chart is read from top to bottom. Line numbers refer to lines in the BASIC program in listing 1.

introduced to store digraphs can be used for storing undirected graphs by ignoring the distinction between initial and terminal vertices and pointers. In the case of undirected graphs, a single pointer would serve as well as two pointers and occupy less storage space. If you are enterprising, you can work out the details of this variation and write the appropriate program yourself. Figure 3 compares storage requirements.

Generating Lists Under Program Control

Have you wondered why the lists have been searched from bottom to top and why the pointers are linked backwards? By doing so, you can simplify the task of generating the pointer lists.

The Nassi-Schneiderman chart given in figure 4 shows the logic followed by the BASIC program of listing 1. Here is some additional explanation. Numerals refer to line numbers in listing 1.

300 Assume that you are linking the initial pointers (with L = l). The initial vertex of edge E is stored in V.

310 If the vertex number V has not been recorded as an initial vertex up to now, you have found the end of its chain of initial pointers. Skip line 320 because there is no previous pointer to link up with.

320 If V has been previously recorded as an initial vertex, get the location of its earlier occurrence in EDGE from VERTEX and set the initial pointer PTR(E, 1) of edge E to point to this location.

330 Record the location E of V in list EDGE in VERTEX(V, L). This is the lowest location of V in EDGE that is known at this time. If V occurs again as an initial vertex further down in EDGE, this lower location will be recorded.

Graph Applications

Some obvious examples of graphs and digraphs that occur in the real world have been mentioned: communication and transportation networks. There are more abstract systems that also have an undirected or directed graph structure.

Complicated projects consisting of

26 February 1980 © BYTE Publications Inc

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BYTE February 1980 27

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thousands of interdependent tasks are often planned with the aid of graphtheoretic methods. The tasks can be considered as the vertices of a digraph; their interdependencies can be expressed as directed edges.

This approach allows managers to visualize the problems about which they must make decisions, and gives the managers the opportunity to delegate routine work to the computer. The maximum and minimum times for project completion and the effects of delays upon parts of the project or upon the whole project can be calculated by simple software routines.

The first large-scale project to

which these methods were successfully applied was the development of the Polaris missile system. Today, use of project networks is a standard management technique.

If you are interested in applying graph theory to the social sciences, you should read Structured Models: An Introduction to the Theory of Directed Graphs by Harary, Norman, and Cartwright.

Closing Observation

This article cannot end without observing that almost all users of computers are intimately familiar with one form of directed graph, the flowchart. ■

REFERENCES

Aho, A V, J E Hopcraft, and J D Ullman. The Design and Analysis of Computer Algorithms. Addison-Wesley Publishing Co, Reading, MA, 1974. Christofides, N. Graph Theory: An Algorithmic Approach. Academic Press, New York, 1975.

Deo, N. Graph Theory with Applications to Engineering and Computer Science. Prentice-Hall Inc, Englewood Cliffs, NJ, 1974.

Harary, F, R Z Norman, and D Cartwright Structural Models: An Introduction to the Theory of Directed Graphs. John Wiley and Sons Inc, New York, 1965. Ore, O. "Theory of Graphs," Colloquium Publications of the American Mathematical Society, American Mathematical Society, Providence, Rl, volume 38, 1962.

28 February I9S0 © BYTE Publications Inc

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BYTE February 1980 29

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Gispcis's Circuit Gellsp

Copyright © 1980 by Steven A Ciarcia. All rights reserved.

A Computer-Controlled Wood Stove

Steve Ciarcia

POB 582

Glastonbury CT 06033

"Come inside, Roger, and get out of the cold." I held my kitchen door ajar as he crossed the front yard towards me. Great clouds of leaves blown by the cold wind furiously encircled him. The landscape was stark and gray, and all weather indicators pointed toward an impending snowstorm.

Roger, a local electrician, had come by to discuss some electrical work I needed done on a new garage I was building. As he stepped through the doorway he remarked, "Sure looks like snow. Have you got enough gas for your Jeep in case you need to plow yourself out of this wilderness?"

Roger's remark reminded me that the terms "picturesque" and "remote" are often synonymous when describing a home in Connecticut. The only place I had been able to buy a house with more than half an acre of land was 25 miles from civilization. And while Roger's controlled, old Yankee humor prevented him from laughing out loud as he spoke, the thought of me, basically a kid from the city, independently plowing my 300 yards of driveway seemed to produce a slow-forming look of amusement.

The Jeep he was referring to was about 20 years old and was used only for plowing. I rather enjoyed the straightfoward task of rearranging snow with it. A certain spirit of excitement came over me each time I stepped into the driver's seat and

asked myself the all-important question posed by every adventurer: "I wonder if this heap will start?"

My neighbor, who shares the chore of plowing, thought I was a sissy when I finally added lights to the Jeep for night driving. Somehow, not seeing the rocks makes hitting them

Photo 1: The Hydrostove is installed in the corner of the Circuit Cellar. Take note of the two copper pipes coming out the rear of the stove into the wall. The pipes, which are buried behind the wall and above the ceiling, go to the furnace, which is 35 feet away.

more fun for him. I never did ask him how he had broken the driveshaft the previous year.

I continued my masochistic thoughts of the Jeep. "It should be okay," I said, "but frankly, if it breaks down, I think I'll just hibernate in the cellar for the winter."

Roger still had not taken his coat off as he added, "You might expect to enjoy such an arrangement, but I think you will find that you need outside services more than you think."

"Give me an example."

Roger uncomfortably shrugged his shoulders. Something other than the conversation was bothering him.

"Oil is a good example. You heat with oil, right? How do you propose to fill your oil tank if the truck can't get down the driveway? I'll bet this glass barn you have here almost requires a direct pipeline to the refinery."

I did not exactly relish having my contemporary home called a glass barn but there was some merit to his statement. I retorted, "Who needs..."

Roger interrupted me in mid-statement. "Speaking of heat... what are you running here, a sauna?"

'Take your coat off, Roger. Maybe then you won't be so hot. I'm not so sure you even need both the wool shirt and sweater you have on."

Tossing his coat across to the nearest chair and tugging on his sweater, he continued. "Whenever I

32 February 1980 © BYTE Publications Inc

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BYTE February 1980 33

Photo 2: Logs up to 24 inches in length are placed in a grate which consists of waterfilled tubes.

visit anyone during the winter I presume their house is at 60 degrees like mine. It must be 12 degrees outside, and..." he walked over to the thermostat, "according to this it's 75 degrees in here!"

"I don't usually have it this warm, I was just testing the heating system now that it's computer-controlled."

"What's there to control? Turn the oil burner on longer and it gets hotter."

"Who said anything about an oil burner?"

"Electric heat is even worse!" he quickly added.

"We have oil heat... but it hasn't been on for two days. All I have now is one wood stove."

Roger's momentary blank stare and open mouth were instantly replaced with a look of disbelief. Standing there by the thermostat he quickly scanned the room. With extreme skepticism he replied, "What are you handing me? A twelve-hundredsquare-foot room, twelve-foot ceiling, three hundred square feet of glass and seventy-five degrees? I don't see any stove!" Roger walked over to a hot-air duct near one of the windows, stooping down and holding his open palm over the opening he exclaimed, "Wood stove, phooie! There's hot air coming out of this duct. You have the oil burner on!"

"No, Roger. I have a wood stove down in the Circuit Cellar that is plumbed directly into the central heating system."

"A wood stove? In a hot-air heating system?"

"Well actually, Roger, my heating system is both hot water and hot air, and the wood stove heats water. It's called a hydronic wood stove."

"What the heck is a hydronic wood stove?"

Roger was definitely at a loss for words. I put my hand on his shoulder

Photo 3: In operation, the heat from the fire warms the water in the tubes. This is a relatively small fire. The fire box is usually filled.

and said, "Think of it as Yankee ingenuity. Come on downstairs and I'll explain how it works."

A Hydronic Wood Stove

A hydronic wood stove is just what the name implies. It is a wood stove that heats water. The particular wood stove that I have is trade-named Hydrostove and it is made by HydroHeat Division, Ridgeway Steel, POB 382, Ridgeway PA 15853. Photo 1 shows it installed in the corner of the Circuit Cellar.

The Hydrostove looks like an ordinary wood stove. It is constructed of cast iron and weighs about 400 pounds. The difference between it and a regular wood stove is in the method of heat removal from the burning wood and the ability to channel the energy output into the central heating system.

A regular wood stove produces only radiant energy and is generally a one-room heater unless fans or convection registers are employed to spread the heat around. The surface temperature of such stoves can approach the temperature of the burning wood itself, and great care must be taken to keep combustible material more than 4 feet away.

Typical wood-stove operation is to put in a full load of wood, get it good and hot (warming up the room to around 75° F), and then close the dampers to reduce the heat output. This is the only way to keep the room from becoming unbearably hot. An unfortunate byproduct of this process is that a slow, smoldering fire creates creosote buildup in the chimney. Since only the area directly around the stove is heated, it is likely that an adjacent room will be terribly cold unless fans are used to blow the heat around.

The Hydrostove looks like a regular wood stove, but it operates quite differently. Rather than a solid castiron grate, the hydronic stove's firebox is a network of water-filled pipes. These pipes completely encircle the fire, with the burning wood being placed directly on the pipes. Photos 2 and 3 demonstrate this. The inlet and outlet of this water jacket are accessible through two pipe fittings on the rear of the stove. (Since I knew that I wanted a hydronic stove when I built the Circuit Cellar, I had the pipes installed behind the brick wall and

34 February 1980 © BYTE Publications Inc

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BYTE February 1980 35

HYDRO/AIR HEATING SYSTEM

HOT WATER ZONE

ZONE 3

CIRCUIT CELLAR BASE BOARD

\\\\\\\\

-HOT AIR ZONES

BEDROOMS

a

ZONE 3

WALL

THERMOSTAT

<TC3>

Fl AND F2 ARE INTERNAL AQUASTATS

STANDARD OIL HOT WATER BOILER APPROX. 120,000 BTU/HR

ZONE 2 WALL

THERMOSTAT (TC2)

ZONE I

WALL

THERMOSTAT

<TC|>

VALVE A

hx] 5h

Figure 1: Diagram of the hydro/air, oil/wood heating system in use by the author.

TIN IN

TOUT OUT

BURNER CONTROL ON/OFF

HYDRONIC WOOD STOVE

APPROX. 50,000 BTU/HR TO WATER

AND 12,000 BTU/HR RADIATED

WOOD FIRE

through the ceiling. The oil burner is about 35 feet from the Hydrostove.) When a fire is started in the stove, the heat is extracted through the water rather than being radiated directly into the room.

With dry, hard wood, the stove generates about 62,000 BTU per hour (with an additional 12,000 BTU per hour going up the chimney) and is quoted by the manufacturer to be about 85% efficient. I cannot say at this time exactly how much of this is transferred to the water as opposed to how much is radiated. I can only state my experience: with the stove burning at full capacity for 6 hours, the brick wall 1 foot from the stove is on

ly warm to the touch, and wood can be piled next to the stove (about 2 inches away) with no possibility of ignition. For this same 6-hour period, the Circuit Cellar temperature will never exceed 75° ¥ unless a higher temperature is set on the central heating system thermostat. You would definitely know that it is a hot stove, but anyone inspecting the raging fire inside is usually quite surprised how little heat is felt in comparison to a regular wood stove.

A New England Experiment— First, the Basics

The heating system shown in figure 1 is commonly called a hydro/air

system. It consists of an oil hot-water boiler and hot-air heat distribution. The oil burner heats water, which in turn circulates through a hot-water heat exchanger. A fan blows over the heat exchanger coils and circulates the hot air through the ducts to each room. Such a system combines the even-temperature, residual-heating benefits of a hot-water circulator with the pleasant, humidified, filtered warmth of a hot-air system. A third zone of baseboard heat was added when the Circuit Cellar was built.

Perhaps the best way to start is to explain how an oil-fired hot-water heating system works. Neglect for a moment zones 1 and 2 and the

Note: The heating system in this article is installed in my home and was built to my specifications. I do not intend this as a general construction article, but rather a documented discussion of the elements of the system with emphasis on the controls involved. I must point out that while this article specifically describes a computercontrolled hydro heating system,

general use of a Hydrostove does not require the sophisticated control I have outlined. It is only the unique combination of machinery and an empirically determined operating algorithm that suggests ease of operation through computerization. In truth, the computer's primary value is in the addition of a significant measure of safety rather than the convenience

implied. Through its attachment as a supervisory controller, the computer can more accurately maintain safe operating temperatures and dump excess heat in an overtemp condition. As of the time of this writing, two cords of wood have been burned in the stove testing this complete system and the result has been safe, satisfying, and reliable operation.

36 February 1980 © BYTE Publications Inc

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Hydrostove in figure 1. Think of it strictly as the oil burner connected to one circulator pump and the zone 3 baseboard. This is essentially what many homes have. There may be multiple rooms, but only one circulation loop.

Most people think that the thermostat on the wall turns the oil burner on. Actually, this thermostat only controls the on/off operation of the circulator pump; it generally has no direct connection to the burner itself. Operation of the boiler depends upon the temperature of the water flowing into the heating coil section and the temperature setting TA of the aquastat (water conduit thermostat). Water flows from the hot-water boiler to the baseboard and is drawn back through the circulator pump to the boiler again. If the temperature of this water is greater than the aquastat setting, the burner stays off. If however, the temperature is below T^, the burner turns on, adding heat until the water in the loop reaches T^. Usually TA has a wide hysteresis; the high and low limit of variation is separated by about 20° F. For most boilers the low setting is 160° F, and the high is 180° F. The hysteresis reduces the frequency of oil burner starts.

To get heat in a room, you turn up the wall thermostat, which starts the pump. As the water moves through the baseboard, it loses heat to the room. The water is then reheated by the oil burner.

Now, consider the addition of the Hydrostove as shown in figure 1. Any water circulating through zone 3 will necessarily pass through the coils of the stove if valves A and B are opened and C is closed. This circulation in itself does nothing to the operation of the heating system. If, however, you build a fire in the Hydrostove as in photo 3, heat is added to the water returning from the baseboard and flowing into the boiler. If the fire is large enough, the temperature of the water flowing out of the Hydrostove is greater than TA, the oil burner never turns on, and the house will effectively be heated by the Hydrostove.

There are a few other considerations. Unlike the oil burner which can be selectively turned on when heat is needed, once the wood stove is on, it runs for quite a while and the heat

must be continuously removed; otherwise, the water in the pipes will turn to steam. Pressure-relief valves will keep the system from exploding, but who wants a steam bath in their living room? In a single-zone system, the circulator pump must remain on until the fire is out. In a gravity-feed system, the pump must stay on until the fire is lowered to the point where the water stays below the boiling point and can effectively be radiated by the heating loop.

Consider the Hydrostove as a continuous source of heat. If the Hydrostove is cranked up to produce 40,000 BTU per hour, then 40,000 BTU per hour must somehow be removed. The task of heat dumping is much easier on a multi-zone system. Take for example, three zones with capacities of 40,000 BTU, 30,000 BTU, and 20,000 BTU, respectively. Whether or not a room thermostat is calling for heat, you must turn on either the pump for zone 1, or the pumps for both zones 2 and 3. Consider the case when zones 2 and 3 are used as heat dumps. If the zone 1 thermostat were to trip suddenly, the control system would have to make a choice. It could add zone 1 to the pool and share 40,000 BTU among three zones or immediately drop zones 2 and 3 off the line and send everything to zone 1 until it reaches its thermostat setting again. While the previous choice can easily be made, load sharing is an interesting consideration. It is much easier to switch zones on and off while performing load sharing than to try to directly control the heat output of the wood fire to any degree.

An additional complication occurs when using heat exchangers. Heat exchangers cannot effectively transfer heat unless the blower is on. The fans in these units are thermostatically controlled. When the water flowing through the exchanger reaches a set temperature, the fan turns on, extracting heat. There is considerable delay and overshooting in the operation of these units. While the average hourly heat transfer of a heat exchanger might be 40,000 BTU, it may be 10,000 BTU with the blower off and 50,000 BTU with it on. In a quick heat-dump situation, it is sometimes necessary to override the blower thermostat and force the

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38 February 1980 © BYTE Publications lnc

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BYTE February 1980 39

Photo 4: The computer I/O interface for the heating control system is attractively housed. It includes a display of either the input or output temperature of the Hydrostove and a real-time status display of the circulators and blowers.

blower on to maintain stable conditions throughout the rest of the system.

Using a Hydrostove

How much you benefit from the addition of a hydronic wood stove depends quite heavily on the rest of your heating system. Above all, it must be capable of taking the full heat

output of the wood fire. This can be 62,000 BTU per hour. Since my oil burner is rated at 120,000 BTU per hour, and I had added the third zone of baseboard to the Circuit Cellar, I concluded that the connection would be quite safe.

My usual method of manual operation is to use the stove only on very cold days and to build as large a fire

Control

Outputs

Signal

Type

Function

TC,

Contact closure 200 mA

Circulator pump - zone 1

TC,

Contact closure 200mA

Circulator pump - zone 2

TC3

Contact closure 200 mA

Circulator pump - zone 3

F,

Solid state relay 5 A 220 VAC

Heat exchanger blower zone 1

F,

Solid state relay 5 A 220 VAC

Heat exchanger blower zone 2

XFER

Contact closure 5 A 115 VAC

Oil burner power

Inputs

Status

Level

Function

TC,

TTL

TC2

TTL

0 pump

off

TC3

TTL

1 pump

on

F,

TTL

0 blower

off

F,

TTL

1 blower on

T,„

Analog

range 40° to 240°

F

T„

Analog

4° to 115°

C

Table 1: Computer I/O lines used with the heating control system.

as possible. It is initially started with both dampers open, but once the fire is going strong the flue damper is closed to reduce the amount of heat going up the chimney. At the time the fire is started, the zone 1 circulator pump is turned on continuously with a switch, overriding the motor-start relay. This keeps some water flowing through the stove at all times. Zones 2 and 3 are normally left in their "heat on demand" thermostat-controlled mode. If the Circuit Cellar cooled down and its circulator pump kicked in, it would be drawing heat from the stove along with zone 1.

Our house is large, but given my method of use, no single heating zone can sustain the full output of the Hydrostove for long periods of time. Generally, the water temperature will be between 75° and 90° C. To maintain a 20° to 22° C (68° to 72° F) temperature through the house on a very cold day, I have to keep the fire box continually filled. This means filling the stove with wood every 3 to 4 hours. (Before you choke and compare it to 12 hours for a regular airtight stove, remember that I am talking about heating a whole house). After a few hours of use, even in this large house, the temperature in the rooms in zones 2 and 3 will reach the wall-thermostat set points, no longer continuously demanding heat from the stove. This leaves all the heat going to zone 1.

Soon, the temperature of the water coming out of the wood stove starts to climb above the safe high limit of 88° C (measured 35 feet away at the furnace). When the indicator hits around 98° C, a loud noise can be heard in the pipes because the higher temperature water nearest the hot coals within the stove is turning to steam. Unless you want the safety valve to blow, filling the room with steam, you have to override the automatic settings of either or both of the thermostats of zones 2 and 3 to get rid of some of the excess heat. It may also be necessary to manually turn on the heat-exchanger blowers for zones 1 and 2 for the reasons I previously outlined.

This occurrence is rare, and I generally have about 10 minutes to react to the situation and throw all the manual switches required. After using the system and determining that this is a potential problem, I installed a digital temperature indicator that

40 February 1980 © BYTE Publications Inc

■

^H

[II

X. INTR1K DATA SYSEMS I SUPERBRAIN

J J J 1 1

The Honor Graduate

There's been a lot of talk lately about intelligent terminals with small systems capability. And, it's always the same. The systems which make the grade in performance usually flunk the test in price. At least that was the case until the SuperBrain graduated with the highest PPR (Price/Performance Ratio) in the history of the industry.

For less than $3,000*, SuperBrain users get exceptional performance for just a fraction of what they'd expect to pay. Standard features include: two dual-density mini-floppies with 320K bytes of disk storage, up to 64K of RAM to handle even the most sophisticated programs, a CP/M Disk Operating System with a high-powered text editor, as

*Quantity one. Dealer inquiries invited.

Circle 22 on inquiry card.

sembler and debugger. And, with SuperBrain's S-100 bus adapter, you can even add a 10 megabyte disk!

More than an intelligent terminal, the SuperBrain outperforms many other systems costing three to five times as much. Endowed with a hefty amount of available software (BASIC, FORTRAN, COBOL), the SuperBrain is ready to take on your toughest assignment. You name it! General Ledger, Accounts Receivable, Payroll, Inventory or Word Processing . . . the SuperBrain handles all of them with ease.

Your operators will praise the SuperBrain's good looks. A full ASCII keyboard with a numeric keypad and function keys. A non-glare, dynamically focused, twelve inch screen. All in an attractive desktop unit weighing less than a standard

office typewriter. Sophisticated users will acclaim SuperBrain's twin Z-80 processors which transfer data to the screen at 38 kilobaud! Interfacing a printer or modem is no problem using SuperBrain's RS232C communications port. But best of all, you won't need a PhD in computer repair to maintain the SuperBrain. Its single board design makes servicing a snap!

So don't be fooled by all the freshman students in the small systems business. Insist on this year's honor graduate . . . the SuperBrain.

sinte3tec Cdata

=SYSTEMS,

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

BYTE February 1980 41

Why not

kill two birds

with one stone?

If you have an Apple* and you want to interface it with parallel and serial devices, we have a board for you that will do both. It's the AIO.™

Serial Interface.

The RS-232 standard assures maximum compatibuity vnth a variety of serial devices. For example, with the AIO you can connect your Apple* to a video terminal to get 80 characters per line instead of 40, a modem to use time-sharing services, or a printer for hard copy. The serial interface is software programmable, features three handshaking lines, and includes a rotary switch to select from 7 standard baud rates. On-board firmware provides a powerful driver routine so you won't need to write any software to utilize the interface.

jifcp*—«^bL

Parallel Interface.

This interface can be used to connect your Apple* to a variety of parallel printers. The programmable I/O ports have enough lines to handle two printers simultaneously with handshaking control. The users manual includes a software listing for controlling parallel printers or, if you prefer, a parallel driver routine is available in firmware as an option. And printing is only one application for this general purpose parallel interface.

Two boards in one.

The AIO is the only board on the market that can interface the Apple to both serial and parallel devices. It can even do both at the same time. That's the kind of innovative design and solid value that's been going into SSM products since the beginning of personal computing. The price, including PROMs and cables, is $135 in kit form, or $175 assembled and tested. See the AIO at your local computer store or contact us for more information.

—557

2116 Walsh Avenue Santa Clara, California 95050 246-2707

'Apple is a TM of Apple Computers, Inc.

AIO

Serial & Parallel

Apple Interface

'

allowed me to monitor the system as I worked at my desk in the Circuit Cellar. When I saw that the temperature was going above 88° C, I would throw the manual override on the zone 2 circulator pump. If the temperature did not drop, I would continue with the other heat dumping methods. It has never gotten to a point where these maneuvers prove insufficient or where the fire has to be put out. Experience has shown that zone 2's volume of 15,000 cubic feet provides a terrific sink for excess heat. Normal use in this mode barely raises its temperature more than 2° F above its nominal 66° F thermostat setting. (I do not want to leave you with the impression that there is one 90° F room in the house.)

I have not described anything thus far that specifically requires computerization other than for convenience. The real reason is a rather insignificant detail that is discovered only after actually using the stove. A Hydrostove definitely saves oil, as stated. When its output temperature is greater than the aquastat set point, the oil burner does not come on. The problem arises during startup and shutdown when the stove output temperature (Tou,) is less than the setting of the aquastat (T^). The circulator pump has to remain on while there is a fire but, because the circulation loop is running and returning at less than TA, the oil burner keeps coming on. Catch 22!!

If this were a matter of 10 minutes or so, it would not be so bad; but shutdown to the point where the circulator pump can be turned off can take several hours. The alternative is to cut the power to the oil burner when the wood stove is on and restore it when the fire is out. This is what I initially did, until I was staying up all night to shut the stove off. The alternative was to wake up to a very cold house, turn the oil burner on, and have to wait a half-hour to take a hot shower.

Aside from taking in a tenant who would watch the Hydrostove temperature in exchange for room and board, the only reasonable alternative was a more intelligent control system. With the proper sensors, a device could monitor the heat output of the stove (Tou, — T,„), and when it dropped to a predetermined safe point, automatically restore power to

Circle 23 on inquiry card.

new products from

yi/llcrc Data Base Systems. Inc.

HOBS - HIERARCHICAL DATA BASE MANAGEMENT SYSTEM MDBS - OUR FULL NETWORK DATA BASE MANAGEMENT SYSTEM

HDBS FEATURES

• HIERARCHICAL DATA STRUCTURES

ADDITIONAL FEATURES IN MDBS

• HIERARCHICAL AND FULL NETWORK DATA STRUCTURES (CODASYL ORIENTED)

COMMANDS TO ADD, DELETE, UPDATE, SEARCH AND TRAVERSE THE DATA BASE SORTED. FIFO, LIFO, NEXT AND PRIOR SET ORDERING PROVIDED STRAIGHTFORWARD USE OF ISAM LIKE STRUCTURES

• READ/WRITE PROTECTION AT FILE LEVEL

• ONE-TO-MANY SET RELATIONSHIPS ALLOWED

• MULTIPLE LEVELS OF READ/WRITE PROTECTION AT ITEM, RECORD, SET AND FILE LEVELS

• EXPLICIT REPRESENTATION OF ONE TO-ONE. ONE TO-MANY, MANY TO ONE AND MANY TO-MANY SETS

NAMES OF DATA ITEMS. RECORDS, SETS AND FILES ARE WHOLLY USER DEFINABLE

WRITTEN IN MACHINE LANGUAGE FOR MAXIMAL EXECUTION EFFICIENCY AND MINIMAL MEMORY USAGE

SUPPORTS DATA BASE SPREAD OVER SEVERAL DISK DRIVES (MAX. 81. DISKS MAY BE MINI OR FULL SIZED FLOPPIES OR HARD DISKS.

ROUTINES ARE CALLABLE FROM BASIC. PASCAL. FORTRAN. COBOL AND MACHINE LANGUAGE RECORDS CAN BE MAINTAINED IN A NUMBER OF SORTED ORDERS.

NEW DYNAMIC RESTRUCTURING SYSTEM

• RECORD TYPES MAY OWN OTHER OCCURRENCES OF THE SAME RECORD TYPE

• A SINGLE SET MAY HAVE MULTIPLE OWNER AND MEMBER RECORD TYPES

MDBS-DRS FEATURES

ALLOWS ITEM, RECORD AND/OR SET TYPES TO BE ADDED TO OR DELETED FROM AN EXISTING MDBS DATA BASE. THIS ALLOWS THE USER TO RE-DESIGN A DATA BASE AFTER IT IS ALREADY ON-LINE.

THIS FEATURE CAN ONLY BE ADDED TO THE MDBS SYSTEM.

MICRO DATA BASE SYSTEMS, INC

P.O.BOX 248 LAFAYETTE, IN 47902 (317) 742-7388

REQUIREMENTS

• Z-80 APPROXIMATELY 16K MEMORY

• 8080 AND 6502 APPROXIMATELY 20K MEMORY

• IN ADDITION TO THE OPERATING SYSTEM. HOST LANGUAGE,

USER'S PROGRAM AND SOME BUFFER AREA

HDBS and MDBS PACKAGES INCLUDE

RUNS UNDER

>CP/M" WITH MICROSOFT BASIC, COBOL AND

FORTRAN > NORTHSTAR DOS WITH NORTHSTAR BASIC ■ TRSDOS* AND DISK BASIC . NEWDOS AND DISK BASIC « APPLE' DOS AND APPLE' SOFT BASIC 'MACHINE LANGUAGE CALLABLE FORMS

CP/M is a registered trademark of Digital Research Corp. TRS-BO is a registered trademark of Radio Shack/Tandv Corp. Apple is a registered trademark of Apple Computers, Inc.

DDL DATA DEFINITION LANGUAGE ANALYZER/ED ITOR. The user specifies data structures to be used in a Concise Data Definition Language (DDL). The Data Definition Language Analyzer/Editor allows the user to interactively create and edit DDL Specifications and to initialize the data base for use based on these specifications.

260 PAGE USERS MANUAL with extensive documentation of the Data Base Management System

DMS DATA MANAGEMENT ROUTINES. These are the routines callable from the host language (BASIC, PASCAL, etc.) which perform the data base operations of finding, adding, and deleting records; fetching and storing data items; and traversing the (possibly complex) data structure.

SAMPLE APPLICATION PROGRAM AND DDL FILES

RELOCATOR TO RE-ORG ALL ROUTINES

SYSTEM SPECIFIC MANUAL to show how to bring up our software on your computer

HDBS - 280 VERSION

8080 and 6502 VERSIONS

MANUAL ONLY

UPGRADE TO MDBS

S250 $325

S 35

$550

WE ACCEPT

MDBS - Z80 Version

8080 and 6502 VERSIONS

MANUAL ONLY

$750 $825

$ 35

MACHINE LANGUAGE CALLABLE FORMS ADD

$ 75

MDBS -DRS MANUAL ONLY

$100 $ 5

FOR FREE PRIMER CONTACT MDBS.

ADD S2.50 (S6.D0 IF FOREIGN! TO NON-CASH ORDERS FOR HANDLING AND SHIPPING. INDIANA RESIDENTS ADD 4%.

Circle 24 on inquiry card.

BYTE February 1980

43

2a C START J

2b

ACTIVATE HYDRO STOVE CONTROL SYSTEM

DESIGNATE HEAT DUMP PRIORITIES FOR THE THREE ZONES. (IN MY CASE THEY ARE ZONE I, ZONE 2, ZONE 3)

SET CONTROL TO AUTO MODE,TURN OFF OIL BURNER POWER AND TURN ON ZONE I CIRCULATOR

95°C 90°C88°C75°C60°C

NORMAL OPERATING TEMPERATURE

HIGH ALARM (OVERTEMP) LIMIT LOW ALARM LIMIT

HIGH PROCESS LIMIT

LOW PROCESS LIMIT COOLDOWN

YES

YES

YES

TURN OFF ZONE I PUMP AND SET TO MANUAL MODE

RESTORE POWER TO OIL BURNER

TURN ZONE I BLOWER ON

TURN ZONE BLOWER OFF

YES

( EX'T )

TURN ZONE 2 CIRCULATOR ON

TURN ZONE 2 CIRCULATOR OFF

YES

TURN ZONE 2 BLOWER AND ZONE 3 CIRCULATOR ON AS REQUIRED

TURN ZONE 2 BLOWER AND ZONE 3 CIRCULATOR OFF

YES

TURN ON AUDIBLE ALARM AND INITIATE SHUTDOWN PROCEDURES

TURN OFF ALARM

Figure 2: (a) Logic flow for the automatic distribution of Hydrostove heat when output in a three-zone combination hydro and air heating system, (b) Points of importance in the operating temperature range of the system. The actual set points for process and alarm limits depend upon placement of temperature sensors and may vary a few degrees.

In BYTE, algorithmic flow is assumed to proceed down and to the right unless an arrowhead is present to indicate otherwise.

44 February 1180 © BYTE Publications Inc

Get Word Power!

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• Find/Replace with conditional test

**COMINGSOON^^

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Equivalent

gallons

Type of wood

Pounds per

BTU per cord

(gallons per cord)

Hardwoods

cubic foot

fuel oil

1. White Ash

37.5

23,037,000

165

2. Cherry

31.0

19,043,920

136

3. Hickory

45.0

27,644,400

198

4. Maple (red)

33.5

20,579,720

147

5. Oak (chestnut)

41.0

25,187,120

180

6. Walnut

34.5

21,194,040

151

7. Willow

24.0

14,743,680

105

Softwoods

8. Douglas Fir

30.0

18,429,600

132

9. Ponderosa Pine

25.0

15,358,000

110

10. White Spruce

25.0

15,358,000

110

Table 2: Comparison of wood heat values for various species of wood available in North America and their equivalent in gallons of fuel oil per cord of wood. (These estimates are generally accepted by industry.)

the burner and shut off the circulatorpump override.

Computer-Controlled Heating System

My heating system is not technically a computer-controlled wood stove. It is rather a system designed specifically to efficiently distribute the heat from a wood stove, to safely dump excess heat in an effective manner, and most importantly, to restore the entire system to its standard configuration when the fire is out. I am merely outlining one application of the many that are conceivable when the heating system has been connected to a computer. Complete energy management is a possibility; or, at the very least, total energy out

put can be closely monitored and recorded. I am working on these areas, but for now, the topic is control.

Virtually any personal computer can suffice as the controller. The logic is straightforward and relatively uncomplicated. It is outlined in the flowchart shown in figure 2. Proper control of the three zones and the Hydrostove requires a special interface to connect the computer to the various blowers and pumps. Table 1 is a list of the signals in question.

The control outputs from the computer are, in essence, all contact closures, whether it be through mechanical or solid-state relays. The use of relays provides electrical isolation between the computer and the

heating system. It further prevents potentially dangerous loops between 115- and 220-VAC powered components.

The three zone thermostats are low-voltage AC circuits that can be directly controlled through a reed relay, as shown in figure 3. The relay contacts are connected in parallel with the thermostat. With the thermostat contacts open, a logic 1 control signal closes the relay and provides an alternate current path to pull in the pump-start relay. By monitoring the voltage across the relay contacts, it is possible to directly monitor the activity of the circulator pump and determine its operational status at any time. If the contacts are open, current flows through the optoisolator lightemitting diode (LED), producing a logic 0 status at the output. When closed, no current flows and the logic value is 1. My application required only the ability to turn on a pump which may not already be running. However, to accommodate complete functional control of the pumps, the thermostat can be disconnected as shown.

The interface to the heat exchanger blowers, shown in figure 4, is similar. This time however a solid-state 7 A 220 VAC relay is used. The power to the blower is 5 A 220 V rather than low voltage AC as before. A 7 A solid-state relay was chosen because of its size and low cost.

FROM PARALLEL OUTPUT PORT

COMPUTER INTERFACE

ICI 7406

ctlO

STATUS <CD

NORMALLY OPEN

+ 24V

^>c^

A IN9I4

+ 5V

; 2.2K

TTL LEVEL SIGNAL TO PARALLEL INPUT PORT

LITR0NIX

IL-I

OPTOISOLATOR

>

COMPUTER GROUND /77

IN400214)

100/iF -r 50V

-w

NORMALLY OPEN

-o

fl

ROOM

THERMOSTAT

55°-80°F

-o

PUMP MOTOR START RELAY

15- 30 VAC '

<3

I20VAC

-<3

'DISCONNECT THERMOSTAT IF COMPUTER IS TO HAVE SOLE CONTROL OF CIRCULATOR PUMP.

CTL 0 I

DON TCARE

ERMOSTAT

PUMP

STATUS

OPEN

OFF

0

OPEN

ON

1

CLOSED

ON

1

Figure 3: Isolated interface for computer control of a typical oil-fired, hot-water, 1/4-horsepower circulator pump. The 7406 opencollector inverter (ICI) requries a 5 V supply to pin 14 and a ground connection to pin 7.

46 February 1980 © BYTE Publications lnc

m

WllkliKK

the answer.

m

Corvus—the company that brought Winchester technology to the microcomputer—is now delivering the solution to backup for less than $1500.

It's called the Corvus MIRROR®, a backup employing lowcost removable media with a total capacity of up to 100 million bytes each. In approximately ten minutes, you can transfer an entire ten million byte disk without operator intervention.

Corvus is the company that gives you a complete systems solution to the mass storage needs of microcomputers. Our systems have fully compatible hardware and software for the Applet (including Apple Pascal), S-100 Bus, TRS-801, and now the LSI-11 and ALTOS computers. We utilize proven Winchester technology with IMI-7710 drives. Up to four eight-inch disks can be used with our Z-80 based controller.

Interested in our new removable-media backup or our pace setting Winchester systems? Both are available now. Call or write for full information.

CORVUS SYSTEMS, Inc.

900 S. Winchester Boulevard San Jose, California 95128 408/246-0461

«**

t Apple Is a registered trademark of Apple Computers, Inc. ITRS-B0 Is a registered trademark of Radio Shack, a Tandy Co.

Circle 26 on Inquiry card.

'

FROM

PARALLEL .—.

OUTPUT CTL V-S>

PORT

STATUS <ZJTO

PARALLEL INPUT PORT

COMPUTER INTERFACE + 5V

HEAT EXCHANGER BLOWER

ICI 7404

0*

ICI

7404

7A 220V

SOLID STATE RELAY

SIGMA 226REI-5AI

OUT

fj

+ 5V

LITRONIX

IL-I

OPTOISOLATOR

HEAT EXCHANGER THERMOSTAT 120°- 200°F

220 VAC

o

>

4

m

. IN5252 24 V ZENER

IOOjiF 50V

A IN4004(4)

-W-l

<H

I2K I0W

CTL

THERMOSTAT

BLOWER

STATUS

0

OPEN

OFF

0

1

OPEN

ON

1

DON'T CARE

CLOSED

ON

1

Figure 4: Isolated interface for computer control of a heat-exchanger blower fan. The 7404 hex inverter requires a 5 V power supply to pin 14 and a ground connection to pin 7.

Monitoring the activity of the blowers is accomplished simply by checking the voltage across the motor. The 220 V present when the motor is on is reduced and rectified to run an optoisolator as before. With

voltage present, the status output is high (logic 1).

Finally, the computer must be able to monitor the output temperature of the Hydrostove. This signal is an analog voltage that is proportional to

Photo 5: An internal view of the I/O controller containing relays, optoisolators, and analog interface components.

temperature. Various sensors such as thermistors or thermocouples could be used, but a more practical device is a temperature sensor device such as the LM334 from National Semiconductor. When configured as in figure 5, the output of ICI (monitored at V,„) is 10 mV per degree Celsius. It may have a nominal offset of something like 2.5 V, but if the temperature rises 10° C the output will go up 100 mV. ICs 2 and 3 provide gain and offset adjustment and are configured to prohibit accidental negative excursion of the output if the temperature sensor goes open circuit. The result is a circuit that converts a change in temperature to a change in voltage. By adjusting the gain and offset, 0° C can be an output of 0 V and 100° C can be 1 or 10 V. A Fahrenheit scale can be just as easily calibrated by setting a different gain and offset.

To read this signal, the computer must have an analog-to-digital converter interface. This can be either a true successive-approximation analog-to-digital converter as in figure 6, or the discrete set-point level detector of figure 7. The choice

48 February 1980 C BYTE Publications Inc

Step up to your next computer.

■■i

STEP UP TO A C4P FROM OHIO SCIENTIFIC

You know about computers. In fact, you probably own one now. One that you might be thinking of expanding. We have a better idea. Take a giant step into the personal computing future with an amazing, new C4P from Ohio Scientific.

SPEED SEPARATES THE COMPUTERS FROM THE TOYS

The C4P MF has execution speed that . is twice as fast as Apple II or Commodore PET and over THREE times as fast as TRS-80. They are many times faster than the recently introduced flock of video game type computers. And, as if that weren't fast enough, the C4P nearly doubles its speed when equipped with the GT option.

Just look at the back panel of the C4PMF.

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All the 1/0 you'll ever need!

Apple II. Commod'irePET. TRS-80, and Alan BOO are registered trade names ol Apple Computer trie , Commodore Busmose Machines Ltd. Radio Shack, Alan, respectively.

T^i

SOUND

1 —programmable tone generator

200 — 20KHz 1 —8 bit companding digital to analog

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output.

HUMAN INPUT EXPANSION

2—8 axis joystick interfaces 2—10 key pad interfaces

HOME INTERFACE

1 —AC-12 AC remote control interface

DISPLAY

32 x 64 with upper and lower case 2048 Characters. 256 x 512 effective Graphic Points 16 Colors

SOFTWARE

Ohio Scientific offers a comprehensive library of both systems and applications software for the C4P.

The C4P is an outstanding premium computer — years ahead of the market. We know because there's nothing quite like it for the price, anywhere. And probably won't be for a very long time.

C4P*698

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All the features of the C4P plus real time clock, home security system interface, modem interface, printer interface, 16 parallel lines and an accessory BUS. The C4P MF starts with 24K RAM and a single mini-floppy and can be directly expanded to 48K and two mini-floppies. Over 45 diskettes now available including games, personal, business, educational and home control applications programs as well as a real time operating system, word processor and a data base management system.

Computers come with keyboards and floppies where specified. Other equipment shown is optional.

For literature and the name of your local dealer, CALL 1-800-381-6850 TOLL FREE.

1333 SOUTH CHILLICOTHE ROAD AURORA, OH 44202 • [216] 562-3101

Circle 27 on Inquiry card.

+ 10 TO 15 V

V~ ADJUST

V!N= lOmV/K

VTEMP -C> 0-IOV

0°-IOO°C

(REDUCE RANGE TO LESS THAN 5V IF USING THE CIRCUIT IN FIGURE 6 )

Figure 5: Solid-state temperature sensor. The range of the output voltage (VTEMP) is reduced to less than 5 V if the circuit in figure 6 is used.

depends upon whether you need to know the exact temperature or just significant set points.

If data acquisition is the dominant consideration, then consider the circuit of figure 6. IC8 is an 8-channel, 8-bit analog-to-digital converter that is bus-compatible with most microprocessors. Figure 8 outlines its internal structure. As configured, it is attached to function as ports F8 through FF, with port F8 corresponding to input channel 0, and port FF corresponding to channel 7. The volt

Photo 6: To effectively use this control device, it is important to have accurate temperature measurements. The LM334 temperature sensor is easily attached to the Hydrostove return pipe by wrapping Teflon plumbing tape around it.

age on channel 0 is read by initiating an output to port F8. This causes the address of 000 to be stored and the conversion process started. After about 100 microseconds, the time necessary for conversion, the channel analog value can be obtained by reading an input from port F8. A similar procedure is used to set and read the other channels.

If you are interested strictly in control, then the circuit of figure 7 is much simpler to use. If a 0 to 10 V input represents a range of 0 to 100° C and there are eight comparators, each could be set to trigger 12.5° C higher than the preceding one. A better approach is to arrange the majority of set points to cover the control and alarm range rather than to cover insignificant temperature ranges. For example, bit b0 could be set to trigger at 60° C. It is not necessary to care much about temperatures below that point. The range of prime interest is

from about 75° C to 95° C. Dedicating 5 set points within this range, another perhaps between 60° C and 75° C and a final overtemp indicator at 98° C should prove more than adequate.

My system uses a combination of both interfaces, using set points for control inputs and a true analog-todigital converter to determine actual heat output from the stove.

A further enhancement is a visual display indicating the real-time status of the system components and a readout of the actual temperature. The prototype controller is shown in photos 4 and 5. It serves as the interface between the heating system and the computer, and contains most of the electronics described in this article as well as other enhancements not discussed at this time. While all the control decisions are actually made by the computer, the display gives me

Text continued on page 56

Number

Type

+5V GND

-12 V

+ 15V

IC1

LM334

see figure 5

IC2

LM301A

4

7

IC3

LM301A

4

7

IC4

LM339

12

3

IC5

LM339

12

3

IC6

REF-01

see figure 7

IC7

LM301

4

7

IC8

ADC0808

see figure 6

IC9

74LS30

14 7

IC10

74LS02

14 7

IC11

7400

14 7

Table 3: Power and ground connections for the integrated circuits that are used in the circuits of figures 5, 6, and 7.

SO February 1980 © BYTE Publications lnc

Here's to your health! Six Vitaf acts programs for you and your family

Being healthy and happy is so very important. And now you can use your Applet PET/CBM'" or TRS-80'" computer to help stay that way.

Introducing six new Personal Software'" Vitafacts Series programs for your health: Growing Up, Heart Attacks, Talking About Sex, Drinking & Drugs, Birth Control, and Your Blood Pressure.

Using a Vitafacts program is like getting advice from your family doctor. Accurate, up-to-date medical information about physical and mental health, presented in a friendly, straightforward way. You'll feel even more confident knowing that each program is approved and endorsed by The College of Family Physicians in Canada, where the Vitafacts Series is created by The Richmond Software Group and Medifacts Ltd.

Each program includes a manual with diagrams and glossary, a computer cassette, and an audio cassette. The audio tape uses short dramas and straight talk to tell the story. Then the computer exercises verify your new knowledge. And because you use your knowledge right away, you remember more. It's fun! And a great way to learn.

Growing Up helps families cope with the teenage years. Teenagers learn more about their physical and emotional changes, and parents learn more about helping their children through it all.

Heart Attacks describes what one is, how to recognize it, what to do

TM-Vitafacts is a trademark of Medifacts Ltd.; Apple is a trademark of Apple Computer, Inc.; PET is a trademark of Commodore Business Machines, lnc.;TRS-80 is a trademark of the Radio Shack Div. ofTandyCorp.

Circle 28 on inquiry card.

-most important—

when someone is experiencing one, andhow to help prevent one.

Talking About Sex, presented by two of Canada's foremost sex counselors, offers to adults the proper information and appropriate attitude for a satisfying sex life.

Drinking & Drugs. No lecturing or talking down. Just straight facts about the very real dangers of alcohol and drugs. Prepared for teenagers, but good for adults.

Birth Control explains clearly and completely conception, birth and prevention of unwanted pregnancies. Important information for teenagers, and helpful for adults.

Your Blood Pressure. No one is immune to the risks of high blood pressure. Knowledge is your best defense, and this program has the information.

"Vita" means "Life" in Latin. We hope these programs make your life healthier and happier. Retail price is just $19.95. Ask your Personal Software dealer for a demonstration, and for our new catalog. Call or write to find your nearest dealer. (408) 745-7841 Personal Software, Inc., 592 Weddell Dr., Sunnyvale, CA 94086.

sssF"

VTTAfiHCTS SERIES

I/O READ C>1/0 WRITE D>

COMPUTER

ADORESS

BUS

A7 £>

A6C^ A5C^ AlC^ A3 O"

A2 OAl Q>

A0[>

Rl IK

10 TURN POTENTIOMETER

>

^°y^

OPTIONAL INTERRUPT

D

VREF = 5.000V

-u

25V TANTALUM

OUT ENABLE

ADDRESS

LATCH

ENABLE

ICB

ADC0808

'CC GND

-o»«

-OD2

-D>m -D»'

-OD5 -(Z>D6 -D>D7

COMPUTER I/O DATA BUS

^]|N0 ^CHlNl -<Ol«2 -<ZllN3 -OH™ ^dlN5 -<Z|lN6

-On"

8 ANALOG INPUTS

IC11 j. 1» 7100

V, I *—• d llo 2

680pp

CLOCK FREQUENCY NOMINAL 500kHz

Figure 6: An 8-channel, 8-bit analog-to-digital (A/D) converter using a National Semiconductor ADC0808 data acquisition device.

FINALLY, Apple II software for the discerning computerist, and the not-so-discerning beginner

AppleAids

Little Tricks™

A series of carefully explained subroutines containing a potpourri of useful programming techniques in Integer Basic and Applesoft, such as specific key stroke identification, timing loops, disappearing question marks on input, no question marks on input, and many more. Cassette (24K) 14.95 Disk(32K) 19.95

Scroll Control"

Have you ever wondered why you cannot list an Integer Basic or Applesoft program one screen-page at a time? So have we. and we did something about it! Our machine language Scroll Control, hidden in RAM so as not to "bump" into your program, can be engaged or disengaged at a flick of the keyboard. Why be frustrated when instead you can control the scroll? Cassette 9.95 Disk 14.95

Compulaw™ Series

Alitax Estimator™

This Applesoft program, prepared under the supervision of an attorney, estimates disposable income after alimony and child support payments and federal taxes. For use by laymen and attorneys. 1980 tables. Cassette (24K) 9.95 Disk (32K) 14.95

Pensionner™

A companion to Alitax Estimator in Applesoft designed to calculate the present value of a pension in states in which a pension is subject to division in marital dissolution cases. Cassette (24K) 9.95 Disk (32K) 14.95

N.J. res. add 5% sales tax

Apple II and Applesoft are registered

trademarks of Apple Computer, Inc. Add $1.50 /item, shipping and handling 'professional, but not a substitute for

legal advice

Form-It-Out™

A series of routines in Integer Basic and Applesoft containing detailed explanation and examples of programming techniques necessary to professionalize your screen output. Included are right and center justification, windowing, tabbing, cursor positioning among others. Cassette (24K) 14.95 Disk (32K) 19.95

Track & Sector List™

This is the ultimate disk utility. Instead of a catalog, have you ever seen those dreaded words "I/O ERROR"? Is all lost? NO! Now your disk may be saved. Also you can eliminate bad sectors, remove control characters imbedded in file names, and more.This machine language program is supplemented by extensive tutorial documentation worth its weight in gold. Disk only (32K) 29.95

Hex ecimal Learning Tree™

My ABC's™

An early learning Integer Basic program using over one hundred and fifty high resolution graphic letters and pictures in a drill-and-practice tormat designed to develop identification of capital and small letters, and association of letters with pictures. Scoring capability allows monitoring. Child tested and teacher recognized. Cassette (48K) 14.95 Disk 19.95

Now I Can Rhyme™

A companion to My ABC's in Integer Basic. The child selects those high resolution pictures which rhyme. Score-keeping capability allows monitoring. Incorporates progressive levels of difficulty. Cassette (48K) 14.95 Disk (48K) 19.95

P.O. Box 774M Morristown, NJ 07960 (201)539-3770

INCORPORATED

52 February 1980 © BYTE Publications Inc

Circle 29 on inquiry card.

BYTE February 1980 53

VOLTAGE REFERENCE

SETPOINT ADJUST POTS

+ VREF

2907

'i o

io.ooov

m

VinO

NOTE: COMPARATOR OUTPUT IS LOGIC 0 WHEN V|N IS LESS THAN SETPOINT.

OUTPUT IS LOGIC I WHEN V|N IS EQUAL TO OR GREATER THAN SETPOINT.

OB

'I

OBI

OB2

OB3

8 BIT . PARALLEL / INPUT

PORT

0»B4

C>B5

OB6

OB7

Figure 7: A discrete set-point-level detector. This method is cheaper than the method shown in figure 6 and can be used only -when it is necessary to detect a small number of temperature ranges. The eight comparators on the right-hand side of the figure are wired to have their outputs go from logical 0 to logical 1 when a certain temperature (determined by the position of the 10 K potentiometer) is exceeded. The status of the eisht bits can be used to determine what range of temperature the interface is currently in. The voltage reference integrated circuit REF-01 (IC1) may be obtained from Precision Monolithics, 1500 Space Park Dr, Santa Clara CA 95050.

54 February 1980 © BYTE Publications Inc

IS READY ...

WITH SYSTEMS AND SOFTWARE!

... Feel Free to Mil and Match

SVSTEIV11

$1750.00

Twin Mini IU/32K

SYSTEM?

1 - $139.00

Leedex monitor

"l " V

$110.00

Keyboard

Base 2

$499.00

IYIULTIUSER CAPABLE

$1650.00

$775.00

32K 8-100 mainframe T/v 912 Terminal

SYSTEM?

Tl 810'

$1350.00

1 Megabyte Double Density storage

IYIULTIUSER CAPABLE

$1950.00

$985.00

$1850.00

64K s-too Mainframe T/u I

systeRu

$3450.00

Diablo 1620

2 megabyte Quad Density storage

MULTIUSER

t (Dealers Only)

tDesk Enclosure

Software:

CPM 1.4 $115.00

CPM 2.0 $150.00

MPM MULTIUSER . $350.00

32 megabyte dish

atit model 300

CBASIC . . MBASIC . . FORTRAN COBAL. . . PASCAL. .

$115.00 WORDSTAR $495.00

$300.00 ACCTS. PAYABLE. . . . $699.00

$395.00 ACCTS. RECEIVABLE . $699.00

$625.00 GENERAL LEDGER. . . $899.00

$265.00 SUPERSORT $225.00

DATABASE . . . INVENTORY . .

QSORT

NAD

LETTERRIGHT

SI 50.00 $440.00 $ 95.00 S 79.00 S 180.00

West:

DELTA PRODUCTS

1653 E. 28th Street Long Beach, Calif. 90806 Tel: (213)595-7505

Circle 31 on Inquiry card.

East:

DELTA PRODUCTS

1254 South Cedar Road New Lenox, Illinois 60451 Tel: (815)485-9072

Telex: 182-126 DELTMAR SGHL

START

CLOCK

ANALOG { INPUTS

C> END OF CONVERSION

6 CHANNELS MULTIPLEXING ANALOG SWITCHES

ADDRESS DECODER

Vcc GND REF(+)

REF(-)

TRISTATE CONTROL

Figure 8: National Semiconductor's ADC0808/0809 CMOS data acquisition system. The 8-bit converter uses successive approximations. The device interface is to most 8-bit microprocessors.

Text continued from page 50:

the added satisfaction that everything

is working correctly.

Back to Roger's Visit

Roger studied the stove very carefully. He was surprised at the simplicity of the idea of supplemental wood heat, but somewhat aghast at the overall complexity of the entire system. The concept of computer control did not concern him in the least but I sensed that my apparent independence from OPEC fostered a little competitive jealousy.

"What about wood? You still will have to get wood for the stove," Roger commented, pointing out a possible serious limitation.

"I'm surprised you didn't notice when you drove in. There are eight cords of wood piled outside. I don't expect to use them all this winter. Wood, unlike oil, is one of those things you can easily stockpile if you have enough storage space."

"Oh yeah, I did notice a few piles beside the driveway."

Roger was perplexed. He had obviously begun to believe the petroleum company propaganda. The thought of missing an oil delivery meant total destruction of civilization

as far as he was concerned. But he just could not believe that the addition of a wood stove meant independence. Suddenly he smiled as he thought of a sobering reality that I might have overlooked.

"You have to keep the circulator pumps running when the stove is going, right? And if the fire is real hot you may in fact need the blowers on as well?"

"Sure, why?"

Roger had found the Achilles' heel of my heating system. The Hydrostove as I had it configured needed power to run all the pumps and blowers. The actual heat might come from a wood fire, but distribution of the heat throughout the house depended upon the local electric utility. Roger quickly commented, "What happens if the power goes out?"

"Well, I suppose I should be concerned, but I'll have four or five minutes to react."

Roger laughed. "React to what? Living in a steam bath?"

"Perhaps I should show you. Follow me." I led Roger out of the cellar into the garage. In one corner was a large mechanical contraption, part of which was a two-cylinder

engine. Pipes and wires came to it from different directions, all converging at a central control box adjacent to the motor. Without explaining the intricate details involved with this permanent installation (the heating system was enough for Roger this time) I said, "If the utility power goes out, I throw the emergency transfer switch and start my 5-kilowatt generator. It's large enough to run the whole house and then some."

Hesitating, then striking out with one last effort, 'You still need gasoline and that doesn't look like a very big tank."

"Sorry Roger, I thought of that too. This particular unit runs on both gasoline and propane. There's a 100-gallon propane tank outside the garage just for the generator"

"I give up!"

It is just as well that he did. Eventually he would notice the trench going across the driveway from the house to the new garage. When he is installing the wiring for it I hope he doesn't ask why I am running insulated copper pipes underground across to the garage. NEXT MONTH: Investigate the new Intel 8088 processor and build your own five-chip computer. ■

56 February 1980 © BYTE Publications lnc

26 MEGABYTES

Suddenly, S-100 microcomputer systems can easily handle 100 million bytes, because Morrow Designs™ now offers the first 26 megabyte hard disk memory for S-100 systems-the DISCUS M26™ Hard Disk System.

It has 26 megabytes of useable memory (29 megabytes unformatted). And it's expandable to 104 megabytes.

The DISCUS M26™ system is delivered completea 26 megabyte hard disk drive, controller, cables and operating systemVfor just $4995. Up to three additional drives can be added, $4495 apiece. I

The DISCUS M26™ system features the Shugart SA4jp08 Winchester-type sealed media hard disk drive, in a handsome metal cabinet with fan and power supply.

The single-board S-100 controller incorporates intelligence to supervise all data transfers, communicating with the CPU via Y three I/O ports (command, status, and data). The controller has the ability to generate interrupts at the completion of each command to increase system throughput. There is a 512 byte sector buffer on-board. And each sector can pe individually write-protected for data base security.

The operating system furnished with DISCUS M26™ systems is the widely accepted CP/M* 2.0.

See the biggest, most cost-efficient memory ever introduced for S-100 systems, now at your local computer shop. If unavailable locally, write Morrow Designs,™ 5221 Central Avenue, Richmond, CA 94804L , Or call (415) 524-2101, weekdays 10-5 Pacific Time.

*CP/M is a trademark of Digital Research.

Q /MORROW DESIGNS™

Thinker Toys

Circle 32 on inquiry card.

'

Solving Problems Involving Variable Terrain

Part 1: A General Algorithm

Scott T Jones

271 NW 38th St

Boca Raton FL 33431

A General Definition of Terrain Problems

In business, in industry, and especially in conflict simulation, problems are often confronted that involve terrain, the surface of the planet Earth. These problems can usually be expressed in terms of movement on a map. This article defines terrain as any feature on the map that affects movement. The term movement cost will be defined as the quantitative effect of the terrain on movement.

An example of a hiker traveling cross-country from one town to another town will be used. The hiker may travel one mile across level ground in 15 minutes, while requiring 30 minutes to travel one mile when the ground is sloping gradually upward. It can be said that the movement cost for the terrain called level ground is one, while the movement cost of the terrain called upward-sloping ground is two. Here the movement cost is in terms of time.

For another example, consider a construction company building a road. The cost to build one mile of roadway over solid ground might be $100,000, while the cost to build one mile of road over marshy ground might be $500,000. Thus, you can say that the movement cost is one for solid terrain and five for marshy terrain. In this case, the movement cost is expressed in terms of money.

In both examples, there is an existing problem of moving from one point to another across a terrain map while incurring the minimum movement cost. Now examine another variation of this problem.

58 February 1980 © BYTE Publications Inc

Consider a cable television company that is investigating the extension of underground coaxial cables out to a new area. It is known that these new cables will provide a fixed return on investment due to the increased number of customers. Therefore, only a fixed amount of money can be spent to place these cables. Using a map of the terrain and the known costs of placement over the various types of terrain to be encountered, the company can decide whether the extension is feasible.

The purpose of this article is to describe a general solution to these and other related problems.

Representing Generalized Terrain Problems

The first step in solving a terrain problem is to superimpose a grid on the map that is to be used. This will allow you to refer to each location on the map via its coordinates and identify a particular type of terrain with each location.

For simplicity, a standard rectangular grid and coordinate system will be utilized. The map is now a matrix of squares that can be referred to by their row and column in the matrix. The size of the squares should be chosen so that each square effectively has only one type of terrain in it.

The second step is to determine the movement cost for each type of terrain. This requires that a study be made to determine the type of cost involved in the problem. This cost must then be scaled so the movement-cost figure for

Text continued on page 62

6809 PROCESSING POWER/

The Percom SBC/9. Only $199.95.

Fully compatible w th the SS-SOjbuT™ requiring no modification of tbe'mother board, memory ojr l/0"^t6ts—■--.thfl SBC/9™ is also a coprfplete, singleboard control corrjpuler with its own ROM operating! "systefTH-BA.M. peripheral ports and a full-range baud' clock generator.

Make the SBC/9 the heart of your computer and put to work the most outstanding microprocessor available, the 6809.

the Mighty 6809

Featuring more addressing modes than any other eight-bit processor, position-independent coding, special 16-bit instructions, efficient argument-passing calls, autoincrement/ autodecrement and more, it's no wonder the 6809 has been called the "programmers dream machine."

Moreover, with the 6809 you get a microprocessor whose programs typically use only one-half to two-thirds as much RAM space as required for 6800 systems, and run faster besides;

And to complement the extraordinary 6809, the Percom design1 team has developed PSYMON™, an extraordinary 6809 operating system for the SBC/9" PSYM0N~— Percom SYstem MONitor

Although PSYMON "includes a full complement of operating system commands and 15 externally callable

"trademark of Percom Data Company, Inc.

utilities, what really sets PSYMON" apart is its easy hardware adaptability and command extensibility.

For hardware interfacing, you merely use simple, specific device driver routines that reference a table of parameters called a Device Control Block (DCB). Using this technique, interfacing routines are independent of the operating system.

The basic PSYMON" command repertoire may be readily enhanced or modified. When PSYMON" first receives system control, it initializes its RAM area, configures its console and then 'looks ahead' for an optional second ROM which you install in a socket provided on the SBC/9* card. This ROM contains your own routines that may alter PSYMON" pointers and either subtly or radically modify the PSYMON" command set. If a second ROM is not installed, control returns immediately to PSYMON"

Provision for multi-address, 8-bit bidirectional parallel I/O data lines for interfacing to devices such as an encoded keyboard.

A serial interface Reader Control output for a cassette, tape punch/reader or similar device.

An intelligent data bus: multi-level data bus decoding that allows multiprocessing and bus multiplexing of other bus masters.

Extended address line capability — accommodating up to 16 megabytes of memory — that does not disable the onboard baud rate clock or require additional hardware in I/O slots. On-board devices which are fully decoded so that off-card devices may use adjoining memory space. Fully buffered address, control and data : lines. '

The SBC/9", complete with PSYMON"in ROM, 1K of RAM and a comprehensive users manual" costs lust $199.95. .

PEFCOM

PERCOM DATA COMPANY, INC.

211 N. KIRBY GARLAND. TEXAS 75042

(214)272-3421

Percom peripherals for personal computing'

To place an order or request additional literature call toll-free 1-800-527-1592. For technical information call (214] 272-3421. Orders may be paid by check, money order, COD or charged to a VISA or Master Charge account. Texas residents must add

5% sales tax. Circle 25 on inquiry card.

PRICES AND SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE.

Circle 33 on inquiry card.

BYTE February 1980 59

Welcome to Percom's Wide World

Each LFD mini-disk storage system includes:

• drives with integral power supplies in an enamel-finished enclosure

• a controller/interface with ROM operating system plus extra ROM capacity

• an interconnecting cable

• a comprehensive 80-page users manual

Circle 34 on inquiry card.

Low-Cost Mini-Disk Storage in the Size You Want.

Percom LFD mini-disk drive systems are supplied complete and ready to plug in the moment they arrive. You don't even have to buy extra memory. Moreover, software support ranges from assembly language program development aids to high-speed disk operating systems and business application programs.

Mini-disk storage system prices:

The LFD-400® and -400EX® systems and the LFD-SOO** and -800EX® systems are available in 1-, 2- and 3-drive configurations. The -400, -400EX drives store 102K bytes of formatted data on 40-track disks, and data may be stored on either surface of a disk. The -800, -800EX drives store 200K bytes of formatted data on 77-track disks.

The LFD-1000® systems (not pictured) have dual-drive units which store BOOK bytes on-line. The LFD-IOOO"- controller accommodates two drive systems so that a user may have as much as 1.6M bytes on-line.

1-DRIVE

2-DRIVE

3-DRIVE

MODEL

SYSTEM

SYSTEM

SYSTEM

For the SS-50 Bus:

LFD-400®

$ 599.95

$ 999.95

$1399.95

LFD-800®

895.95

1549.95

2195.95

For the EXORciser* Bus:

LFD-400EX®

$ 649.95

$1049.95

$1449.95

LFD-800EX®

945.95

1599.95

2245.95

LFD-1000®

(dual) $2495.00

(quad) $4950.00

—

HlUjtll

•llll ff If

EXORciser Bus LFD-400EXP SOOEX^ Systems

Circle 35 on inquiry card.

Upgrade to 6809 Computing Power. Only $69.95

Although designed with the SWTP 6800 owner in mind, this upgrade adapter may also be used with most other 6800 and 6802 MPUs. The adapter is supplied assembled and tested, and includes the 6809 IC, a crystal, other essential components and user instructions. Restore your original system by merely unplugging the adapter and a wire-jumpered

DIP header, and re-inserting the original components. Also available for your upgraded system is PSYM0M» (Percom SYstem MONitor), the operating system for the Percom 6809 single-board computer. PSYM0N® on 2716 ROM costs only $69.95. On diskette (source and object files), only $29.95.

Data Terminal & Two-Cassette Interface— the CIS-30+

,A,E TERMINA

300 "Nl

ON

,200 l°CAl

•

I*' AUIO

pEflSOM

CIS-30+_

Circle 36 on

inquiry card

• Interface to data terminal and two casselte recorders with a unit only 1/10 the size of SWTP's AC-30.

• Select 30, 60 or 120 bytes per second cassette interfacing: 300, 600 or 1200 baud data terminal interfacing.

• Optional mod kits make CIS-30+ work with any microcomputer. (For M1TS 680b, ask lor Tech Memo TM-CIS-30+-09.)

• KC Standard/Bi-Phase-M (double frequency) cassette data encoding. Dependable self-clocking operation.

• Ordinary functions may be accomplished with 6800 Mikbug* monitor

Prices: Kit, $79.95; Assembled, $99.95. Prices include a comprehensive instruction manual. Also available: Test Cassette, Remote Control Kit (for program control of recorders), IC Socket Kit, MITS 680b mod documentation and Universal Adapter Kit (converts CIS-30+ for use with any computer).

of 6800 Microcomputing.

6800/6809 SOFTWARE System Software

6800 Symbolic Assembler — Specify assembly options at lime of assembly with this symbolic assembler. Source

listing on diskette $29.95

Super BASIC — a 12K extended random access disk BASIC tor the 6800 and 6809. Supports 44 commands and 31 functions. Interprets programs written in both SWTP 8K BASIC (versions 2.0, 2.2 & 2.3) and Super BASIC. Features: 9-digit BCD arithmetic, Print Using and Linput commands, and much

more. Price $49.95

TOUCHUP'* — Modifies TSC's Text Editor and Text Processor for Percom mini-disk drive operation. Supplied on

diskelte complete with source listing $17.95

Operating Systems

INDEX"^ — This easy-to-use disk-operating and file management system for 6800 microcomputers is fast. I/O devices are serviced by interrupt request. INDEX® accesses peripherals the same as disk tiles — new devices may be added without changing the operating system. Other features: unlimited number ol DOS commands may be added • over 60 system entry points • display only those files at or above user-specified file activity level • versions available for SWTP MF-68, Smoke's

BFD-68 and Motorola's EXORciser*. Price $99.95

MINIDOS-PLUSX® — An extension of the original MfNIDOS® for LFD-400'* mini-disk systems, MINIDOSPLUSX^ manipulates files by six-character names. Supports up lo 31 files. Resident commands include Initialize, Save, Allocate, Load, Files (directory list), Rename and Delete. Supplied on 2708 ROM with a minidiskette that includes transient utilities such as Copy, Backup, Create, Pack and Print

Directory. Price $34.95.

PSYMON'5' — Percom SYstem MONitor for the Percom single-board/SS-50-bus-compatible 6809 computer accommodates user's application programs with any mix of peripherals without modifying programs. PSYMON® also features character echoing to devices other than the communicating device, sophisticated register and memory dump routines and

more. Price (on 2716 ROM) $69.95.

WINDEX'" — Described in detail elsewhere on this page. Business Programs

General Ledger — For 6800/6809 computers using Percom LFD mini-disk storage systems. Requires little or no knowledge of bookkeeping because the operator is prompted with non-technical questions during data entry. General Ledger updates accounl balances immediately — in real lime, and will print tinancial statements immediately after journal entries. User selects and assigns own account numbers; tailors tinancial statements to firm's particular needs. Provides audit trail. Runs under Percom Super BASIC. Requires 24K bytes of RAM. Supplied on minidiskette with a comprehensive users manual.

Price $199.95.

FINDER™' — This general purpose data base manager is written in Percom Super BASIC. Works wth 6800/6809 computers using Percom LFD-400® mini-disk drive storage systems. FINDER'-* allows user to define and access records using his own terminology — customize file structures to specific needs. Basic commands are New, Change, Delete, Find and Pack. Add up to three user-delined commands. FINDER plus Super BASIC require 24K bytes ol RAM. Supplied on minidiskette with a users manual. Price $99.95

Mailing List Processor — Powerful search, sort, create and update capability plus ability to store 700 addresses per minidiskette make this list processor efficient and easy to use. Runs under Percom Super BASIC. Requires 24K bytes of RAM. Supplied on minidiskette with a users manual. Price $99.95. From the Software Works Development and debugging programs for 6800 nCs on diskette:

Disassembler/Source Generator $30.95

Reloc'tng Disas'mblr/Segmented Text Gen $40.95

Disassembler/Trace $25.95

Support Relocator Program $25.95

Relocating Assembler/Linking Loader $55.95

SmithBUG" (2716 EPROM) $70.00

Circle 37 on inquiry card.

'/2-Price Special on Hemenway Software!

CP/68+ disk operating system $ 49.97

STRUBAL+1: compiler $124.97

EDIT68 text editor $ 19.97

MACRO-Relocating Assembler $ 39.97

Linkage Editor (LNKEDT68) $ 24.97

Cross Reference utility $ 14.97

'-Irademark of Percom Data Company, inc.

* trademark of Motorola Corporation ^Trademark of Hemenway Associates Company

• "SmithBUG is a trademark of the Software Works Company

This programmable processes display stantly in real-time. The Electric Window™ resides completely in main memory so control is accomplished by direct MPU access to the character-store memory and display control registers. Peer at the screen and you look right into video display memory space while you input and manipulate text — an indispensable feature for efficient screen editing and word processing. The Electric Window™. It's worth looking into. Features include:

• Programmable CRT controller chip that provides extraordinary versatility in software control of horizontal and vertical formatting, cursor positioning, scrolling and Start/Reset functions.

• A standard ASCII 128-unit ROM character generator which generates easy-toread 7x12 dot-matrix characters with lower case descenders. Plus. . .

• Provision for an optional ROM that may be programmed for special symbols or characters.

• Resides entirely in 2K on-board RAM mapped into main memory.

Circle 38 on inquiry card.

VIDEO DISPL CONTROLLER

changes in

The Electric Window.® Worth Looking Into. $249.95

• An optional software driver program called WINDEX™ that complements the fast, hardwareimplemented functional capability of the controller. WINDEX™ will auto-link to PSYMON™, the monitor for the Percom SBC/9™ single board computer. The ROM version of WINDEX™ costs $39.95. The minidiskette version (with source and object files) sells for $29.95.

• Up to 24 80-character lines — programmable.

• Program control of display highlighting.

• Program interlaced or non-interlaced scan.

• Use either standard video monitor or modified tv

Now Available! the SBC/9T MPU/Control Computer

(Single-Board-Computer/6809) — stands alone as a control computer, but also ^

compatible with the SS-50 bus for use as an MPU card. Includes PSYMON® (Percom < SYstem MONitor) in a 1K ROM and provides for additional 1K of ROM. Also includes 1K ; of RAM. Features: Super Port — provision for multi-address, 8-bit bidirectional data j lines • an intelligent data bus for multi-level data bus decoding • an on-board 110-baud ~ to 19.2 kbaud clock generator • extended address capability — to 16 megabytes — without disabling baud clock or adding hardware. And much more. Supplied with ?

PSYMON® and comprehensive users manual. Price $199.95.\

See full page ad elsewhere in this magazine for all of the SBC/ST8features. c

Full Feature Prototyping PC Boards

All ol the features needed for rapid, straightforward circuit prototyping. Use 14-, 16-, 24- and 40-pin DIP sockets • SS-50 bus card accommodates 34- and 50-pin ribbon connectors on top edge, 10-pin Molex connector on side edge* I/O card accommodates 34-pin ribbon connector and 12-pin Molex on top edge

/O Bus Card: $14.95

Lrtft^Xl

■

mm

SS-50 Bus Card: $24.95

I/O card is l-'A inches higher than SWTP 1/0 card • interdigitated power conductors • contacts for power regulators and distributed capacitance bypassing

use wire wrap, wiring pencil or solder wiring • tin-lead plating over 2-oz copper conductors wets quickly, solders easily

FR4-G10 epoxy-glass substrate.

Circle 40 on inquiry card.

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Text continued from page 58:

each type of terrain is an integer multiple of the cost unit.

The movement cost for any one square on the terrain map is considered to be the cost to enter the terrain area represented by that square. If you are currently in square X, and wish to move to square Y, then consider the cost of moving into square Y as the movement cost for square Y. The movement cost of square X, the current square, has no effect on the calculation; the movement cost is affected only by the nature of the terrain you are about to enter.

The result of determining movement costs is a cost matrix, C, where C(IJ) is the movement cost of the terrain in the square in the I-th row and J-th column of the map. For all terrain which is effectively impossible to enter, or for which entrance is prohibited, C(/,/) =0 is assigned.

The third step is to generate terrain masks. First determine max, which is the maximum value found among all the movement costs in C. Then for all values k such that 1 < k<Cmax you define the terrain mask T/c where Tk (/,/) is 1 if C(I,]) = k, and Tk(I,J) = 0 otherwise.

Now you should define a scatter function for the problem. The function will produce scatter mappings for use with the terrain masks generated above. The input to this

wwwwwwww

blank

= Clear

WW R R WW

W R R W

R

= Rough

W R J J J W

W J J J W

J

= Jungle

W J WW

W WWWW

W

= Water

WWWWWWWW

Figure 1: Map of a small island with clear, rough, and jungle terrain. The map is represented on a rectangular grid.

function is a boolean array of starting positions (1, if yes; 0, if no). The output is another boolean array of ending positions of moves of distance one from the starting positions. Since distance is a factor, you must define a metric, or distance function, for this problem.

Example of the Procedure

In figure 1, there is a map of a small island with terrain of three types: clear, rough, and jungle. The map has been placed on an 8 by 8 rectangular grid, and each grid square is clearly identified as being a single type of terrain.

Let us return to our hiker traveling cross-country on foot. Suppose that he requires 10 minutes to travel through one square of clear terrain, 20 minutes for rough terrain, and 30 minutes for jungle terrain. The terrain type "water" is effectively impassable in this problem. Thus, the movement cost is in terms of 10-minute periods of time, and you can construct the cost matrix C as shown in figure 2. Since 3 is the maximum movement cost value found in C, you will have three terrain masks: Tl, T2, T3 as shown in figure 3.

Using a rectangular grid, there is a choice between two obvious distance functions with strictly integer values. The first distance function is the "city" metric, which defines the distance between points (a,b) and (c,d) as |« — c| + \b — d\ where |;c| is the absolute value of x. This function derives its name from the fact that in the rectangular system of streets found in a city, no movement is allowed diagonally through blocks. All distances are in terms of the net distance north or south added to the net distance east or west.

The second distance function is the "square" metric, which defines the distance between points (a, b) and (c, d) as the maximum of \a — c\ and \b — d\. Its name is derived from the fact that the shape of the area containing all squares that are N or less units distant is a square, for any integer N.

00000000

0

0

2

2

1

1

0

0

0

1

2

2

1

1

1

0

0

1

2

3

3

3

1

0

0

1

3

3

3

1

1

0

0

1

3

1

1

1

0

0

0

1

1

1

0

0

0

0

00000000 Figure 2: A movement cost matrix for the island map of figure 1.

Scatter Functions

Now it is necessary to define scatter functions CSC and SSC for the "city" and "square" distance functions, respectively. Let A be a matrix the same as C; that is, an 8 by 8 matrix. Let A (J,/) = 0 for all J and /, except for the one location on the map that is to be used as the starting position. A(/,/) will be 1 for the starting location. Matrix A is the input to the scatter function. B will be designated as the output matrix. The notation X(A) to represent the results of applying the function X to the matrix A will also be used. For the city distance function, the function

00000000

00000000

00000000

0 0 0 0 1 10 0

0 0 1 10 0 0 0

00000000

0 10 0 1110

0 0 1 10 0 0 0

00000000

0 10 0 0 0 10

0 0 10 0 0 0 0

0 0 0 1110 0

0 10 0 0 110

00000000

0 0 1110 0 0

0 10 1110 0

00000000

0 0 10 0 0 0 0

0 1110 0 0 0

00000000

00000000

00000000

00000000

00000000

Tl

T2

T3

Figure 3: The three terrain masks that will be superimposed on the movement cost matrix of figure 2.

62 February I960 © BYTE Publications Inc

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BYTE February 1980

63

0 0 0 0 0 0 0 0 0 0 0 0 10 0 0 0 0 0 0 0 0 0 0 0 a. A

0 0 0 0 0 0 0 10 0 0 1110 0 0 10 0 0 0 0 0 0 b. CSC(A)

0 0 10 0 0 1110

11111

0 1110 0 0 10 0 c.CSC(CSC(A))

0 0 0 0 0 0 1110 0 1110 0 1110 0 0 0 0 0 d. SSC(A)

1111 1111 1111 1111 1111

SSC(SSC(A))

Figure 4: Figure 4a is an example of a starting matrix, A. Figure 4b represents the matrix after the CSC (city) scatter function has been applied. The CSC function is then applied a second time to obtain the matrix in figure 4c. Figures 4d and 4e represent the results obtained after applying the SSC (square) scatter function to the matrix in figure 4a once and twice.

CSC will assign to each element of B the value:

B(/J) = CSC(A(/,/)) = A(/J) OR A(/,/+l)

OR A(7J-1) ORA(/+l,/)OR A(/-1,J)

where OR represents the logical OR operation. For the square distance function, the function SSC will assign to each element of B the value:

In both cases, all matrix elements A(I,J) that lie outside the matrix A are to be Considered zero, such as A(0,0). Figure 4a gives an example of a 5 by 5 starting matrix, A. Figure 4b represents the result of applying the CSC function to that matrix. In figure 4c, the result of applying CSC to the matrix in figure 4b can be seen. Figures 4d and 4e represent the matrices obtained after one and two applications of SSC to the matrix in figure 4a.

B(/J) = SSC(A(/,/))

A(/,7) OR A(/,7 + l) OR A(/J-l) ORA(7+l,7) ORAU-1J) OR A(/+l,7+l) OR A(/+l,7-l) OR A(7-1J+1) OR A(/-l,7-l)

Now you can really expand your horizons with the tiny-c structured programming language. The tiny-c owner's manual (including 8080 and PDP-11 source code and tiny-c in C) is still just $40. And we've added these new formats to really egg you on: TRS-80 Level II SYSTEM Format Cassette; CP/M Diskettes with 8080 Source; PDP-11 Diskette; North Star 5" Diskette; KIM and SYM cassettes. And there's more, all available for $50 or less. Order your tiny-c owner's manual today and get the whole story. Call or write: tiny c associates, P.O. Box 269, Holmdel, N.J. 07733. (201)671-2296. You'll quickly discover finy-c is all it's cracked up to be.

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V

Solving General Terrain Problems

You now have everything needed to solve terrain problems: a map with a grid and coordinate system, a movement cost matrix, a set of terrain masks, a matrix of starting positions, and a distance function with associated scatter function.

These solutions will probe all possible paths, incrementing by one unit at a time until your resources are exhausted or your goal is reached. If you reach the goal before you run out of resources, the proposed journey is feasible; if you can reach the goal only after running out of resources, the proposal is not feasible. Furthermore, once a proposed journey is proven to be feasible, you can then retrace the path from the goal back to the starting position to determine an optimal solution to the problem.

Now reconsider the problem of the man walking on the island of figure 1. The city metric and the scatter function CSC will be used. Let the walker's starting point be the square (3,5) on the map in figure 1; that is the clear terrain in the third row and the fifth column. During the first 10 minutes the hiker will expend one unit of cost and can, therefore, move one square north to (2,5) or one square east to (3,6). The hiker cannot move south or west to (4,5) or (3,4) since he has not yet expended enough cost units. Figures 5 and 6a show his starting location matrix and his matrix of possible new locations after 10 minutes, since each of these positions requires only one more unit of movement cost. After another 10 minutes, the hiker can reach the clear terrain squares at (2,6) and (3,7) by moving from the squares reached after first 10 minutes. The hiker could also have reached the rough terrain square (3,4). This would be possible by moving west for 20 minutes from the starting position at square (3,5). All

64 February 1980 © BYTE Publications Inc

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other moves are impossible due to either a lack of sufficient travel time, in the case of the jungle square (4,5), or the presence of impassable terrain, such as the water to the north. Figure 6b shows the possible new locations for the hiker after 20 minutes (two units of movement cost expended).

After 30 minutes, the hiker has finally expended enough units of movement cost to go south from his starting position to the jungle terrain square (4,5). He can now also reach the rough terrain square (2,4) by traveling west for 20 minutes from the clear terrain square (2,5). Figure 6c shows the hiker's possible locations after 30 minutes.

From the above example, it should be clear that movement into terrain with a movement cost of k depends on the position of the object k movement cost units before. Refer to each iteration of the example above as a move. Also, designate the matrix of possible locations after k moves MA: or the /c-th scatter mapping.

This relation can be expressed as follows: the new terrain squares of movement cost k that you can reach on

00000000

00000000

00001000 M0

00000000

00000000

00000000

00000000

00000000

Figure 5: The starting matrix for the island problem with the traveler standing in the clearing at location 3,5.

move n is represented by the matrix A where A(I,J) is equal to Tfc (/,/) AND B(/,/) where B = XSC (Mn-fc). (XSC is the scatter function. AND represents the logical AND operation.) From this you obtain the relation:

Mn = Mn-l OR (Tl AND XSC (Mn-1)) OR (T2 AND XSC (Mn-2))

OR (Tk AND XSCQAn—k))

where k is the minimum of Cm„ and n. In both of these relations, function XSC could be replaced by CSC, SSC, or any other scatter function to allow the use of any other metric or even another grid system, such as the hexagonal grid. The hexagonal grid will be discussed in part 2 with reference to conflict simulations. Figure 7 shows the scatter mappings Ml, M2 and M3 using the square scatter function, SSC. It is left to the reader to verify that this relation holds for both scatter functions.

Using scatter maps, you can prove or disprove the feasibility of these proposals by determining whether this goal is a possible new location in the scatter mappings.

Determining an Optimal Path

Suppose that after n moves, the scatter map Mn finally contains the goal. Therefore, you know that there exists a path from your starting location to the goal which requires a movement cost of n, and you know that no less expensive path exists. To find this path it is necessary to first define the matrices S/c that are the sums of all the

00000000 0 0 0 0 10 0 0 0 0 0 0 1 10 0 00000000 00000000 00000000 00000000 00000000 a. Ml

00000000 0 0 0 0 110 0 0 0 0 11110 00000000 00000000 00000000 00000000 00000000 b. M2

00000000 0 0 0 1110 0 0 0 0 11110 0 0 0 0 10 10 00000000 00000000 00000000 00000000 C. M3

Figure 6: After 10 minutes, the traveler may be in any of three positions (figure 6a). Each of these positions represents a 10 minute or less expenditure of time. After another 10 minutes, the traveler may be in any of the squares indicated by figure 6b. Figure 6c represents squares where the traveler may be after 30 minutes.

00000000

00000000

00000000

0 0 0 0 1 10 0

0 0 0 1110 0

0 0 0 1110 0

0 0 0 0 1 10 0

0 0 0 11110

0 0 0 11110

00000000

0 0 0 0 0 0 10

0 0 0 11110

00000000

00000000

0 0 0 0 0 110

00000000

00000000

00000000

00000000

00000000

00000000

00000 000

00000000

00000000

a. Ml

b. M2

C. M3

Figure 7: The first, second, and third scatter-function mappings using the square scatter function (SSC) as defined by equations in text.

66 February 1980 © BYTE Publications Inc

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BYTE February 1980 67

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00000000

0 0 0 13 2 0 0

00024320

0 0 0 0 10 10

00000000 S3

00000000

00000000

00000000

Figure 8: The third scatter sum using the city scatter function (CSC) for the island example. All moves which are made must conform to the city metric (distance function).

scatter maps MO through Mk. Sk will be referred to as the fc-th scatter sum. Note that S0 = M0. Figure 8 shows the third scatter sum for the function CSC.

The algorithm for finding an optimal path is as follows: beginning at your goal, follow a path of strictly increasing elements of Sn until you reach your starting position, choosing the most rapidly increasing path if more than one exists. Since all the possible locations in MIc are in M/c + 1, for all k, the more quickly a location is reached from the starting point, the higher its value will be in each scatter sum.

For example, if the clear terrain square (4,7) was your goal, you would use the third scatter sum, S3, which is in figure 8. Following the movement restrictions imposed by the city function, you will consider only those locations given by the scatter of the current location to determine the next location on your path. Thus, you will choose your next location from the squares (4,8), (4,6), (5,7) and (3,7).

Square (3,7) will be chosen, since it has the maximum value in S3. In the same manner, squares (3,6) and (3,5) will be chosen so that your optimal path from starting point to goal is (3,5) to (3,6) to (3,7) to (4,7). In the same manner, you can find that the optimal path from (3,5) to (2,4) is by way of (2,5).

When you try to find the optimal path and there are, at some point between the goal and start, two or more possible locations from which to choose, you can randomly choose any one of them with equal success. This algorithm, therefore, will find an optimal path, but not necessarily the only such path.

In Part 1 I have discussed some general terrain problems and demonstrated a few solutions using a rectangular grid. This method is very easy to implement with two-dimensional boolean arrays and lends itself well to most of the problems that will be encountered. One notable exception, however, is the conflict simulation or "war game." These games are usually played on terrain maps of a battlefield, upon which a grid of hexagons is superimposed.

This hexagonal grid (or hex grid) resembles a honeycomb. It eliminates the need for two different metrics, since there are no diagonals, but it requires the definition of a new system of coordinates.

In Part 2 I shall define this coordinate system, a distance function, and a scatter function. I shall also discuss the representation of specific terrain-related game features such as directional terrain (roads and bridges) and "no-exit" terrain (zones-of-control).■

68 February 1980 © BYTE Publications Inc

Circle 45 on inquiry card.

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BYTE News ....

iiiiiiiiiiiiimiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiuiiiiiiiiii iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiitiiiiiiiiiimiiiiiii

VOICE-CONTROLLED CONSUMER PRODUCTS: At a recent electronics show in Japan, several Japanese manufacturers demonstrated voice-response and voice-activation of many consumer products. Sanyo, Toshiba, Sharp, Sony, Hitachi, and Matsushita demonstrated a wide variety of consumer products that respond to oral commands. Using microprocessor-controlled speech analyzers and synthesizers, the processors controlled television channel selection, volume and color control, and operated video games and clocks. Some units talked back to confirm user commands.

It is expected that many of these products will be commercially available in a year or two. Present technology allows registration of up to three persons in the voice-recognition circuit. Manufacturers agree that the voice recognition is not 100% perfect, but that it will be in time.

SOME HOME COMPUTERS FAIL FCC RFI SPECS: The Federal Communications Commission (FCC) has released the results of their tests of personal computer systems for radio-frequency interference (RFI). RFI has become an increasing problem to television and FM radio reception, similar to the citizen's band radio interference problem several years ago. The FCC has proposed as a standard a radiation limit of 100 microvolts per meter at a 3-meter distance.

Early last year the FCC tested the Radio Shack, Apple, Heath, Texas Instruments (TI), Commodore PET, and Southwest Technical Products personal computers. Only the Texas Instruments and Commodore systems met the specification. Atari had submitted and passed the specification earlier.

The standard goes into effect July 1, 1980, and all manufacturers have declared their intention to make necessary modifications to assure compliance with the specifications.

CENTRONICS REVEALS NEW PRINTING METHOD: In a press conference held on November 13, 1979, Centronics Data Corp of Hudson, New Hampshire, demonstrated a new method of printing on paper. A single stylus driven by voice coils through a parallelogram flexure mechanism presses a carbon ribbon against paper to form characters in almost the same way as people write using pens and pencils. Character fonts are switched by changing the controlling software; an almost infinite variety of symbols may be produced, including mathematical, Greek, Chinese, Cyrillic, and Arabic character sets. The prototype Quietwriter typewriter devices print with excellent quality at a speed of 17 cps for English-language character sets. Products using the Quietwriter mechanism may be sold beginning about the third quarter of 1981.

NEW LISP SYSTEM: The LISP Co (T.(L.C)) of Los Gatos, California, has completed their first version of LISP for the Z80. It is a dialect of the MIT LISP-Machine LISP, complete with strings, I/O streams, Muddle's parameter-description mechanism, and comprehensive documentation. This version was done for a major personal computer manufacturer; (T.(L.C)) will soon announce their own version that will include hardware to support the LISP programming environment.

HOBBYIST ELECTRONIC MAIL SYSTEM FORMING: Hobbyists are setting up a low-cost mail system using their microcomputers. This is possible using a $12 software package from the Personal Computer Network (PCNET) committee. With it, a personal computer owner can set up his machine to automatically dial another system or systems at a preset time (usually late at night), deliver messages, and return a status report (delivered or not delivered).

Hobbyists are also setting up dial-in, free-access message systems for discussion purposes using the FORUM-80 software and Radio Shack TRS-80s. Three forums are already in operation: forums devoted to tracing family histories (in Fairfax, Virginia), information on engineering applications of microcomputers (Olathe, Kansas), and applications of microcomputers for the handicapped (Memphis, Tennessee). For more information on these applications, contact Jon Tara, c/o SEMCO, POB 9578, Detroit MI 48202.

COMPUTER COMPANIES GO INTO RETAILING: The latest computer stores are those set up by Digital Equipment Corp (DEC), IBM, and NCR. Following the innovative experiences in computer retailing established by Tandy Corp and independent stores, the traditional computer manufacturers have decided to meet the challenge head on. DEC already has in operation almost twenty "computer stores" where customers can sample the DEC small computers. However, the stores have no inventory and purchases are shipped from a distribution center.

February 1980 © BYTE Publications Inc 69

IBM now stocks their 5110 small business systems at fifty centers where a purchaser can get a system on a cash-and-carry basis. These centers were originally opened to demonstrate and train users, and then the retail operation was added. A typical system sells for $16,000.

NCR has opened two pilot stores in Cincinnati to sell cash registers and small computers in the $15,000 price range. Data General is selling its MicroNOVA system through fifty independent dealers, and Texas Instruments is beginning computer demonstrations in its San Francisco store.

With the cost of small business computer systems decreasing, the profit margin is no longer enough to support the high-cost selling techniques of large computer systems.

MOTOROLA, TANDY AND WESTERN UNION INTRODUCE "GREEN THUMB" SYSTEMS: Sponsored by a grant from the US Department of Agriculture, Motorola and Western Union will set up an experimental agricultural video-telephone information system known as Project Green Thumb. Tandy Corp will manufacture the terminals to be located in 200 farm homes in Kentucky. Farmers, via telephone lines, will be able to access weather, market, and agriculture data from remote computers.

RANDOM NEWS: Atari has filed an appeal with the Federal Communications Commission (FCC) to stay the decision (reported in last month's BYTE News) in which the FCC granted Texas Instruments a waiver on permissible interference standards for personal computers. Atari feels that if other companies can pass the specification, then the TI request should not have been granted .... Texas Instruments will soon have competition in the voice synthesis area. National Semiconductor Corp and ITT Semiconductor are both showing samples of their new synthesizer parts. These integrated circuits are aimed at low-price consumer applications such as talking clocks, telephone-answering equipment and automobile warning devices .... Texas Instruments has introduced four new terminals that have dual-matrix print heads. The head prints two characters with each pass across the page enabling the unit to print 120 characters per second .... MIT (Massachusetts Insitute of Technology) has received a development contract worth several million dollars from Heath Co and Exxon Enterprises. The contract calls for the MIT Computer Science Laboratory to develop an advanced cartridge-disk-based 16-bit microcomputer system for use in office automation. Although initial plans called for MIT to use Zilog's 16-bit microprocessor, it is reported that they have switched to the Motorola 68000 to use memory more efficiently. Both Heath and Exxon will have nonexclusive manufacturing rights, and Exxon will have exclusive software rights .... Chuck Peddle, the developer of the 6502 microprocessor, the KIM-1, and PET computers, has a new product. It is the Commodore 4500 4-bit microprocessor. It represents a radical departure from the 6502 architecture .... Researchers at Bell Labs announced the development of an improved electrochromic display using iridium. It consumes less power and could be cheaper to produce than light-emitting diode and liquid-crystal type displays. It does not have to be energized continuously and is pulsed to turn on and off.

APOLOGY DUE: In the September 1979 BYTE News column, I reported on 16-bit 8086 processor boards for S-100 systems. I regret that I omitted mention of a company that has been making such a board since December 1978. The company is Tecmar Inc, 23414 Greenlawn Ave, Cleveland OH 44122. They sell a complete line of S-100 boards to make up a complete system.

RANDOM RUMORS: Apple Computer will soon introduce the Apple III, and it is rumored that it will not use the 6502 microprocessor. Apple is keeping a tight lid on their plans (bit-slice, perhaps?) for this unit. . . .Digital Research, the firm that developed CP/M, the most popular disk operating system for microcomputer systems, will soon announce a version of CP/M for the Intel 8086 16-bit microprocessor, which will include an assembler program. . . .IMI (International Memories Inc) of Cupertino, California, the first company to ship 8-inch, Winchester-technology, hard disk drives, is rumored to be planning to show a 514-inch, 3-megabyte Winchester drive at the 1980 National Computer Conference in June. Rumor is that there will be at least one other such drive shown at the NCC. . . .

MAIL: I receive a large number of letters each month, as a result of this column. If you wish a response please include a stamped, self-addressed envelope.

Sol Libes

Amateur Computer Group of New Jersey (ACG-NJ)

1776 Raritan Rd

Scotch Plains NJ 07076

70 February 1980 © BYTE Publications Inc

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BYTE February 1980 71

A Computer-Controlled Light Dimmer

Part 2: Implementation

John H Gibson

Physics Department

Alma College

Alma MI 48801

Photo 3: Close-up view of the Heathkit ET-3400 microprocessor trainer wired for use with the demonstration program. The ET-3400 programmable timing module is connected to the trainer's data bus via the eight wires from the left corner of the picture. The synchronizing signal is transmitted over the yellow-black twisted pair at the bottom of the picture. The red-orange, red-white, and redyellow twisted pairs carry the output trigger pulses to the three AC phase controls.

The numbering of the photos, figures, and tables is continued from part 1 of this article, January 1980 BYTE, page 56.

In part 1 is an examination of the basic principles and techniques for achieving proportional AC phase control with a microcomputer and a programmable timer. I would now

like to present a completely workedout demonstration program designed to run on a Heathkit ET-3400 microprocessor trainer. This demonstration program will operate three lamp circuits, giving you keyboard control over the lamps that are to be faded on and off.

In addition to the ET-3400 trainer, you will need an MC6840 programmable timer module, a 7405 hex in

verter (open collector), a synchronizer (from figure 5 in part 1), and three AC phase controls (each from the circuit of figure 9 in part 1). Here is a step-by-step procedure for making the demonstration program work:

1) Plug the MC6840 and the 7405 integrated circuits into the ET-3400 trainer's breadboard socket.

72 February 1980 © BYTE Publications lnc

+5V FROM MICROCOMPUTER

R2

330ft 1/4W

TO _,

MICROCOMPUTER <0 MR<5 INPUT

SYNCHRONIZER

HI

LO

26

ICS MC6840

G3

G2

Gl

03

02

01

27

Ih

MICROCOMPUTER GROUND

+ 5V FROM MICROCOMPUTER A

-^

l_.

IC3 7405

AC PHASE CONTROL #3

AC PHASE CONTROL #2

AC PHASE CONTROL*!

JL

_&

M.

<>—<3

-* 120 VAC 60 Hz

LAMPS

Number

IC3 IC5

Type

7405 MC6840

+5V GND

14 14

Figure 10: Wiring diagram for proportional power control of three AC lamp circuits. Connections between the MC6840 programmable timer and the ET-3400 microprocessor trainer have been omitted for clarity. '

2) Make the connections between the MC6840 and the ET-3400 trainer as shown in table 2.

3) Wire the circuit shown in figure 10.

4) Load the FADER2 program in listing 1 beginning at location hexadecimal 0100.

5) Memory location 0000 stores a minimum delay number for all lamps. If you want the lamps to reach maximum brightness, it should be preset to 00.

6) Fading rates for the three lamps should be preset in memory locations 0001, 0002, and 0003. Setting each of these rate values to hexadecimal FF will cause each lamp to go from complete darkness to full brightness in about 2 seconds. At the opposite extreme, setting each rate value to 01 will cause this change to take 9 minutes.

7) Location hexadecimal 017F con

Author's Note

/ am indebted to Professor Kameswara Rao, of National Semiconductor. Santa Clara CA, for his advice and technical support. This lamp control program was developed and tested in his electronics laboratory at Western Michigan University with the use of a Motorola M6800 cross-assembler resident on Western's PDP-10 computer.

tains the output-pulse-width value hexadecimal IE that was computed in part 1 of this article. This pulse width was computed for a microprocessor clock frequency of 1 MHz. If your system's clock frequency is different, you will have to recompute this pulse width.

A pulse width that is too short will not permit the lamps to darken completely; a pulse width that is too long will cause the lamps to flicker or flash back on at full brightness just when you expect them to be completely dark.

8) The program (listing 1, p. 74) begins execution at location hexadecimal 0100, initializing all variable locations. With the program running, pushing keys 0 thru 7 will fade the lamps on and off in different combinations, according to the binary value of the keys pressed. The lamps' changing values will appear on the ET-3400!s six seven-segment readouts.

9) You can stop the program without turning off the lamps by pushing the 9 (break) key. With the program stopped, you may examine and change registers, all without affecting the lamps. You may then restart the program at location

6840 Pin

6840

Numbers

ET-3400

v„

1

GND

v„

14

+ 5 V

RESET

8

RST

IRQ

9

no connection

RS0

10

A0

RS1

11

A1

RS2

12

A2

R/W

13

R/W

CSO

15

A14

CS1

16

A15

Enable

17

4-2

DO

25

DO

D1

24

D1

D2

23

D2

D3

22

D3

D4

21

D4

D5

20

D5

D6

19

D6

D7

18

D7

Table 2: Connections to be made between the Heath ET-3400 microprocessor trainer and the MC6840 programmable timer.

hexadecimal 0110, which retains previous values in the variable locations.

This demonstration program should be enough to fire your imagination to think of your own applications for this lamp control technique. I will be interested in hearing about programs and applications developed by BYTE readers.

February 1980 © BYTE Publications Inc 73

Listing 1: FADER2, a program written in assembler language for the Motorola M6800 processor to control the light dimmer.

M0T0RDLA M68SAM CR0SS•••• ASSMBLER

M 68S AM IS THE:: PROPERTY OF MOTOROLA SP.O- INC, COPYRIGHT .1.974 TO .1.975 BY MOTOROLA INC

MOTOROLA M6800 CROSS ASSEMBLERr RELEASE 1,2

"ADER2

/ PRESET MINIMUM DELAY

/ PRESET FADING RATE 1 / PRE:SET PAD TNG RATE 2 / PRESET FADING RATE 3

0000.1.

NAM

F

00003

0000

ORG

0

00005

0000

000.1

MINDLY

RMB

1

00007

0001

000.1

RATE!

RMB

1

00008

0002

000.1

RATE2

RMB

i

00009

0003

0001

RATE3

RMB

1

0001.1

0004

000.1

FINAL!

RMB

i

00012

0005

000.1

FINAL2

RMB

00013

0006

0001

FINAL3

RMB

00015

0007

000.1

DELAY 1.

RMB

1

00016

0008

0001

DELAY2

RMB

1

00017

0009

0001

DEI...AY3

RMB

i

000.1.9

000 A

0001

INTER!

RMB

i

00020

00 OB

0001

INTER2

RMB

i

0002.1

OOOC

000.1

INTER3

RMB

i

00023

OOF 7

UIRQ

EQU

♦ OOF 7

/ MONITOR VECTORS HERE ON IRQ

00025

00027 00028 00029

00031 00032

00034 00035

* ADDRESSES IN PROGRAMMABLE TIMING MODULE

8000 8001 8000

800.2 8003

8004 8005

CR1 CR2 CR3

Ml LI

M2 L2

EQU EQU EQU

EQU EQU

EQU EQU

♦ 8000 CRlfl CR1

CR.1.+2 CRi+3

CR.l+4 CR1+5

/ /

MSB

OF LATCH OF LATCH

/ MSB OF LATCH 2 / LSB OF LATCH 2

00037 00038

8006 M3 EQU CR1+6 / MSB OF LATCH 3

8007 L3 EQU CR1+7 / LSB OF LATCH 3

00040

00042 00043 00044 00045

FCOO FDF4 FCBC ED7B

* THESE ET-3400 MONITOR SUBROUTINES ARE USED

RESETINCH RED IS

EQU EQU EQU

DSPLAY EQU

♦FCOO / RETURN TO MONITOR

♦FDF4 / INPUT CHAR FROM KEYBOARD

♦FCBC / RFSET DISPLAY TO 1ST LED

♦FD7B / DISPLAY ROUTINE

00047

* MAKE A COLD START FROM THIS ADDRESS •■•■ ♦OlOO

Listing 1 continued on page 76

74 February 1980 © BYTE Publications Inc

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75

Listing 1 continued:

00049 0.1.00

ORG

$.100

0005:1.

* INITIALIZE DELAYS SO AIL LAMP'S ARE OFF

00053 0:1.00 86 FF CLDSTR LDA A #$FF

00054 0102 CE 0004 LUX #FINAl.

/ MAXIMUM DELAY VALUE / INITIALIZE POINTER

00056 0105 A7 00 INITIA STA A 0?X / STORE #*FF HERE

00057 0.1.07 08 I NX / POINT TO NEXT VARIABLE

00058 0:1.08 SC OOOD CPX #INTER3+1 / LAST OAR I ABLE?

00059 0.1.OB 26 E8 BNE INITIA / RETURN IE NOT DONE

00061. 0.1.OD 01

00062 0.1.OE 01.

00063 0.1. OF 01.

NOP NOP NOP

00065

00067 0110 OF

* MAKE A WARM START PROM THIS ADDRESS - *0.l 10 WRMSTR SEI / MASK IRQ WHILE INITIALIZING

00069 00070 0007.1.

00073 01.1.1 86 B6

00074 0.1.13 06 B7

00076 0115 B7 8000 0007? 0.1.18 E7 8001 00078 01 LB B7 8000

* THESE STEPS CONFIGURE THE TIMERS EOR SINGLE-SHOT

* OPERATION WITH TURN-ON DELAY M(LT1)T AND OUTPUT

* PULSE WIDTH LT#

LDA

A

#*B6

LDA

B

#$B7

STA

A

CR3

STA

B

CR.2

STA

A

CR1

/ CONTROL WORD FOR CR3y CR1 / CONTROL WORD FOR CR2

/ CONFIGURE TIMER 3 / CONFIGURE TIMER 2 / CONFIGURE TIMER 1

00080 0008.1 00082 00083

* ON IRQ? THE ET-3400 VECTORS TO LOCATION

* UIRQ, WE MUST PROVIDE A JUMP INSTRUCTION

* AND A VECTOR TO TRANSFER TO OUR PROGRAM'S

* IRQ SERVICE ROUTINE AT LOCATION tCYCLE.

00085 01IE 86 7E

00086 0.120 97 F?

LDA A #$7E STA A UIRQ

/ LDA A WITH JUMP COMMAND

/ STORE JUMP COMMAND AT UIRQ

00088 0.122 CE 0.1.37

00089 0125 DF F8

LDX #CYCLE / JUMP TO THIS LOCATION

STX UIRQ+1 / STORE #CYCLE AT UIRQ VECTOR

0009.1 0127 OE CI... I

00093 * MAIN PROGRAM LOOP

00095 0128 BD PDF4 KEY JSR INCH

/ CLEAR IRQ MASK

/ GET HEX VALUE OF KEY PUSHED

00097 012B 81 09

00098 01.2D 26 04

CMP A #$09 BNE CONT

/ IS IT "BREAK" KEY?

/ BRANCH IE NOT "BREAK"

00.1.00 012F OF 00.1.01 0.1.30 7E FCOO

SEI / SET IRQ MASK

JMP RESET / GO TO ET-3400 MONITOR RESET

Listing 1 continued on page 78

76 February 1980 © BYTE Publications Inc

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Listing 1 continued:

00.103 0133 8D 09 CO NT BSR NEW FN / SET NEW FINAL VALUES 00104 0135 20 Fl BRA KEY / GET NEXT CLOSED KEY VALUE

00106 * IRQ INTERRUPT SUBROUTINE

00108 0137 8D IE CYCLE BSR CHANGE / CHANGE DELAY VALUES

00109 0:139 8D 3E BSE LOAD / LOAD TIMERS WITH NEW DELAYS 00.110 013D SD 54 BSE SHOW / DISPLAY DELAY VALUES

00.111 013D 3B ET.I

00113 * SUBROUTINE TO CHANGE FINAL. VALUES

00115 013E 81 07 NEWFN CMP A #*07 / VALID HEX VALUE?

00116 0140 22 14 BHI NEWFN4 / BRANCH IF NOT VALID

00118 014.2 CE 0004 LDX #FINAL 1 / POINT TO FINAL!

00.120 0145 46 NEWFN 1 ROR A / SHIFT LAMP(X) BIT INTO 0

00121 0146 24 04 BCC NEWFN2 / BRANCH TO DIM LAMP

00123 0.148 D6 00 LDA B MINDLY / LDA B WITH MIN DELAY

001.24 014A 20 02 BRA NEWFN3

00126 014C C6 FF NEWFN2 LDA B #*FF / LDA B WITH MAX DELAY

00128 014E E? 00 NEWFN3 STA B 0?X / STA B FINAL(X)

00.130 0.150 08 I NX / POINT TO NEXT LAMP

00131 0.151 SC 0007 CPX # FIN A I... 3+1 / LAST LAMP DONE?

00132 0154 26 EE BNE NEWFN1 / RETURN IF NOT DONE

00134 0156 39 NEWFN4 RTS

00.136 * ROUTINE FOR CHANGING DELAY NUMBERS

00138 0157 CE 0001 CHANGE LDX #RATE1 / POINT TO LAMP 1

00.140 015A E6 09 CHNG1 LDA B 9fX / LDA B INTER(X)

00141 015C A6 06 LDA A 6vX / LDA A DELAYCX>

00143 015E Al 03 CMP A 3vX / CMP DELAY(X) WITH FINAL(X)

00144 0160 22 08 BHI BRITER / BRANCH IF DELAY(X)>FINAL<X)

00145 0.162 27 OA BEQ RES TOR / BRANCH IF DELAY (X) «FINAL (X)

00147 0164 EB 00 DIMMER ADD B 0»X / B ~ INTER(X) + RATE(X)

001.48 0166 89 00 ADC A **00 / A » DELAYfX) + CARRY

00149 0168 20 04 BRA RESTOR

00151 016A EO 00 BRITER SUB B 0?X / B ^ INTER(X) - RATE(X)

001.52 016C 82 00 SBC A #$00 / A « DELAY(X) •- BORROW

00154 016E E7 09 RESTOR STA B 9vX / STA B INTERCX)

00155 0170 A7 06 STA A 6vX / STA A DFLAY(X)

00157 0172 08 INX / POINT TO NEXT LAMP

00158 0173 80 0004 CPX #RATE3+1 / DONE WITH ALL 3 LAMPS?

Listing 1 continued on page 80 78 February 1980 © BYTE Publications Inc

MioraHIET

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It is the personal computing service of CompuServe, Incorporated. CompuServe is a nationwide commercial time sharing computer network with large-scale mainframes. MicroNET allows the personal computer user access to CompuServe's large computers, software and disc storage during off-peak hours (from 6 PM to5 AM weekdays, all day on Saturdays, Sundays and most holidays).

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In addition, there is the MicroNET National Bulletin Board for community affairs,

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NEW! MicroQUOTE, a security information system for corporate stocks and public debt. NEW! MicroNET Software Exchange with dozens of new programs available for downloading to your personal computer at a specified charge. NEW! Executive programs forTRS-80, Apple II and CP/M systems (so your machine and ours can talk to each other error-free). You can switch between terminal and local mode while on line.

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Access to the MicroNET service is available in 153 other cities for an additional charge of $4.00 per hour.

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BYTE February 1980

79

Listing 1 continued:

00.1.59

0.176

26

E2

001.61

0178

39

00163

* TH

00.165

0179

CE

8002

LOAD

00167

017C

96

07

00.168

017E

C6

IE

00.169

0180

A 7

00

00.1.70

0182

E7

01

00172

0.184

96

08

00173

0186

A 7

02

00174

0188

E7

03

001.76

018 A

96

09

00177

01.8C

A 7

04

00.1.78

018E

E7

05

BNE

RT

CHNG1

/ RETURN TO DO NEXT LAMP

ROUTINE LOADS THE TIMER LATCHES

LDX

♦ Ml

LDA A DEI...AY1

I...DA B #$1E

STA A OvX

ST A B 1. y.X

LDA A DEI...AY2

STA A 2vX

STA B 3vX

LDA A DELAY3

STA A 4?X

STA B 5»X

/ POINT TO Ml

/ OUTPUT PULSE WIDTH

/ LOAD Ml WITH DELAY1

/ LOAD LI WITH PULSE WIDTH

/ LOAD M2 WITH DELAY2

/ LOAD L2 WITH PULSE WIDTH

/ LOAD M3 WITH DELAY3

/ LOAD L3 WITH PULSE WIDTH

00180 0190 39

RTS

00182

* TH

00.183

* TH

001.85

0191

BD

FCBC SHOW

001.86

0194

CE

0007

001.87

0197

C6

03

00.1.88

0199

BD

FD7B

5 ROUTINE SHOWS THE THREE DELAY VALUES ON ET-3400'S SIX 7-SEGMENT READOUTS♦

JSR PEDIS

LDX #DELAY1

LDA B #03

JSR DSPLAY

/ RESET DISPLAY TO 1ST LED

/ START DISPLAY WITH DELAY1 / DISPLAY 3 BYTES / DISPLAY DELAY1r 2 AND 3

001.90 0.19C 39

RTS

001.92

END

SYMBOL TABLE

MINDI../

final; inter:

CR2 I... 2

RED IS KEY

newfn:

DIMM El ,.>TOP -■

0000 0005 000 A 8001. 8005 FCBC 0128 01.4C 0.164

RATE1 FINAL3 INTER2 CR3 M3

DSPLAY CONT NEWFN3 BRITER

000.1 0006 OOOB 8000 8006 F.D7B 01.33 014E 0.16 A

RATE2 DELAY1 INTER3 Ml I... 3

CLBSIR CYCLE NEWFN4 RESTOR

0002 0007 00 OC 8002 8007 0100 0137 0156 016E

RATE 3

DELAY2

UIRQ

I... 1

RESET

INITIA

NEWFN

CHANGE

LOAD

0003 0008 OOF 7 8003 FCOO 0105 013E 0157 0179

F.TNAL1

DELAY3

CR1

M2

INCH

WRMSTR

NEWFN1

CHNG1

SHOW

0004 0009 8000 8004 FDF4 0110 0.145 015A 0191

80 February 1960 © BYTE Publications Inc

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Programming DeicMes

Gasuse

Mike R Firth, 4712 Northway Dr, Dallas TX 75106

Gasuse is a program I wrote to use facts I record in a notebook in my car to produce useful information. I note the mileage of my car, the cost of the gas, and usually the gallons and dollars of the purchase along with the

state of purchase and date (for tax purposes). Aside from the special features noted below, the program in listing 1 consists of the initialization routine (lines 1010 thru 1084), the main loop (1100 thru 1900), and routines to allow for missing information (2000 thru 2190) and printer output. The main loop continues until 0 is entered for the miles. The program does not permit entering a lower

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1st Output

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mileage than the last mileage reading. The missing information section will permit computations if two of the three items— price, gallons, cost— are known.

The information printed out includes the entered (or calculated) numbers—miles at purchase, dollars, gallons — then two figures for this step—miles since last fill and miles per gallon. Then there are total figures—miles since start of trip and mileage since the start in terms of total dollars and total gallons. The total miles and mileage are figured anew at each step to smooth out errors.

Notes on odd items: lines 40 and 50 save retyping the commands used on the Wang for disk storage. U$ contains the character to move the cursor up one line. This results in the display being solid information, neatly arranged, with data entered on the bottom lines. The Select Print statements after line 8100 are the means of assigning the printed output. Only one device can be selected at a time, where 005 is the video terminal and 215 is the fast printer. Lines 9400 thru 9406 are special functions that relate to special keys on the terminal and permit controlled listing of the program. Wang uses % for image statements, where most BASICS use : in my experience.

Table 1 is an example output from listing 1. (See table 1 and listing 1 on page 124.) Please note that while two of the segment mileage figures vary considerably (17.9 and 40.1), the average mileage stays in the midtwenties. One reason that segment mileage will vary is that the tank is not filled to the same point each time. If 10 gallons are used in 250 miles, but only 5 are purchased the program will give twice the mileage for that segment. However, when one has to fillup with 10 gallons after only 125 miles, the mileage will drop.

Note that the totals are run up each time the program is run, which represent a page in your notebook—all the gas purchased on a trip or a month's driving. To add to a list, simply take the old list's starting mileage and the final totals as the first entry, (see table 1 for example).

82 February 1980 © BYTE Publications Inc

Circle 51 on inquiry card.

CP/M * VERSION 2 FOR TRS-80* MODEL II NOW AVAILABLE

All Lifeboat programs require CP/M, unless otherwise stated.

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D MAC

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D TEX — Text lermatier to create paginated, page-numbered and [ustified copy from source text dies, diroctable to disk or printei . $ 70 $ 15

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G MDBS-DRS — MDBS will Dynamic Restructuring System option which allows altering MOBS data bases when new ITEMs. RECORD!, or SETs are needed without changing existing dala.

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Z80 version requires 20K RAM. 8080 version requires 24K RAM. (Memory requirements are additional lo CP/M and application program.)

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EIDOS SYSTEMS

D KISS — Keyed Index Sequential Search. Offers com(i) piete Mulli-Keyed Index Sequential and Direct Access die management Includes burl-in utility functions tor 16 or 32 bit arithmetic, string integer conversion and string compare. Delivered as a relocatable linkable module in Microsoft format for use with FORTRAN-80 or COBOL80. elC S335 $23

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D SUPER-SORT I — Sort, merge, extract utility as abso

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terminal wilh addressable cursor positioning $445/$25

D WORD-STAR/MAIL-MERGE - As above wilh op

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i*i wilh mail list Irom Dala-Slar or NAD $375/$25

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D CBASIC-2 Disk Exlended BASIC — Non-interactive (Mi BASIC with psoudo-codo compiler and runlime interpreter. Supports lull lile contra1, chaining, integer and e

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D PASCAUZ - 280 r

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Version 3 Upgrade with variant records and strings expected 2/80 $395 $25

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mel'c lor real variables. CP.'M die 10 and assembly language interlace supported. Lacks Sets. Enumeration and Rocord data types. Manual explains BASIC lo PASCAL

conversion. Requires 32K $9S/$30

Source lor PASCAL/MT run time package Requires MAC. (See undor Digital Research.) $50

STRUCTURED SYSTEMS GROUP

D GENERAL LEDGER- Interactive and tlexiWe system providing proof ant) report outputs Customization of COA created interactive!^ Multiple branch accounting centers Extensive checking performed at data entry tor prool. COA correctness, etc Journal entries may be batched prior to posting Closing procedure automatically backs upmpu! files. Now includes Statement Ol Changes in Financial Position Requires

CBASIC-2 S099 525

□ ACCOUNTS RECEIVABLE - Open Hem system wilh oulput lor internal aged reports and cuslomer-orienled stalemenl and billing purposes On-Line Enquiry permits mlormalion lor Customer Service and Credit departments. Interlace lo General Ledger provided if Oolh systems used. Requires CBASIC-2 $699 $25

D ACCOUNTS PAYABLE - Provides aged statements ol accounts by vendor with check writing for selected invoices Can be used alone or wilh General Ledger and/or wilh NAD. Requires CBASJC-2$699/$25 Prices and specifications subject to change wrthoul notice

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Software for most popular 8080IZ80 computer disk systems including NORTH STAR, iCOM, MICROPOUS, DYNABYTE DB8/2 & DB8I4, EXIDY SORCERER, SD SYSTEMS, ALTAIR, VECTOR MZ, MECCA, 8" IBM, HEATH H17& H89, HELIOS, IMSAI VDP42 & 44, REX, NYLAC, INTERTEC, VISTA V80 and V200, TRS-80 MODEL I and MODEL II, ALTOS, OHIO SCIENTIFIC and IMS 5000 formats.

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D INVENTORY CONTROL SYSTEM - Performs

control functions ol adding and depleting slock ilems. adding new items and deleting old ifems. Tracks quantity ol items on hand, en order and back-ordered Optional hard copy audit trail « available. Reports include Master Horn Lisl, Slock Activity. Stock Valuation and Re-order Lisl Requires CBASIC-2 and 48K CP/M . S44SS25

□ ANALYST — Customized dala entry and reporting system User specilies up lo 75 dala items per record Interactive data entry, retrieval, and uadate laciMy makes information management easy. Sophislicaled report generator provides customized reports using selected records wilh mulliplo level broak-poinls lor summanzalion. Requires CBASIC-2. 2<t x 80 CRT, printer and 48K system $225/$15

D LETTERIGHT — Program to creale. edit and lype loiters or olher documenis. Has facihles lo enter, display, doloto and move text, with good video screen presentation. Designed lo integrate with NAD for form loiter mailings, Requires CBASIC-2 $179/525

D NAD Name and Address selection system — interactive mail lis! croation and maintenance arogram with outpul as lull reports with relerencu dala cr restricted mlormalion for mail labels. Transler system lor exlraclion and transfer ol selected records to creale new files. Requires CBASIC-2 $79/$20

D QSORT — Fast sortmerge program tor files with fixed record length, variable field length information. Up to live ascending or descending keys. Full back-up ol input tiles created $95/$20

GRAHAM-DORIAN SOFTWARE SYSTEMS

□ GENERAL LEDGER — An on-line system: no batch® ing is roquired. Entries to olher GRAHAM-DORIAN aciui counting packages aro automatically posted. User establishes customized CO.A. Provides transaction rogisler, record ol |ournal entries, trial balances and monlhly closings. Koops 14 monlh hislory and provides comparison of curronl year wilh previous year. Requires CBASIC-2. Supplied in source S495S35

D ACCOUNTS PAYABLE — Maintains vendor lisl and

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D ACCOUNTS RECEIVABLE - Creates trial balance ® reports, prepares statements, ages accounts and records ■.Si invoices. Provides complete mlormalion describing customer payment activity. Reccipls can Oe posted lo different ledqer accounts. Entries autcmatically update GRAHAM-DORIAN general lodger or runs as stand alone system. Roquires CBASIC-2 Supplied in source. S495 S35

□ PAYROLL SYSTEM — Maintains employee masler i, file. Computes payroll withholding lor FICA. Federal and a Stale laxes Prints payroll register, checks, quarterly reports and W-2 iorms. Can generate ad hoc reports and employee lorm letters wilh mail labels. Requires CBASIC-2. Supplied in source code $49 5 $3 5

D INVENTORY SYSTEM - Captures stock levels,

(C) cosls, sources, sales, ages, turnover, markup, elc.

tu'i Transaclion informalion may bo entered lor reporting by salesman, lypo of sale, date ol sale, etc. Reports available both for accounting and decision making. Requires CBASIC-2, Supplied in source code $49S/$35

ID JOB COSTING — Designod lor general conlractors.

© To bo used interactively with other GRAHAM-DORIAN

D APARTMENT MANAGEMENT SYSTEM - Fi

S nancial management system for receipts and security mj deposits ol apartment projects Captures dala on vacancies, revenues, elc. lor annual trend analysis. Daily report shows lalo renls. vacancy notices, vacancies, income lost through vacancies, etc. Requires CBASIC-2. Supplied in source code S49 5 S3 5

□ CASH REGISTER — Maintains files on daily sales.

'5 Files dala by sales person and item. Tracks sales, over

U rings, rolunds. payouts and total nel deposits, Requires

CBASIC-2. Supplied in source code $495/$35

U tiny C — Interactive interpretive system lor teaching

(x) slruclurod programming techniques. Manual includes lull

source listings $75,540

□ BDS C COMPILER — Supports most major features # of language, including Siructures, Arrays. Pointers. 0 reeursivo function evaluation, linkable with library to 80B0

binary outpul. Lacks dala initialization, long & float type and sialic & register class speciliers, Documentation includes "C" Programming Language book by Kernighan & Ritchie $11'0/$15

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S630 530

D POLYVUEV80 — Full screen editor lor any CRT wilh

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wrap around lor word processing, operations lor manipu

laling Clocks ollext, and comprehensive 70 page manual.

$135/$15

D POLYTEXT/80

:>«< applications Justifies and pagm

generate lorm loiters wilh custom fields and conditional processing. Support lor Daisy Wheel pnnters includes variable pilch |ustificalion and molion optimization. $B5/$15

ALGOL-60 — Powerlul block-slructured language compiler featuring economical run lime dynamic allocation ol momory. Very compact (24K total RAM) syslem implementing almost all Algol 60 report fealuros plus many powerful extensions including string handling direct disk address I/O etc. Requires Z80 CPU . .. $199/$20

' CPIM is .1 trademark ol Dirjltal Research.

■2,80 is a trademark ol Zilog, Inc

■UNIX is a trademark of Bell Laboratories.

"WHATSIT? is a trademark ol Computer Headware Electric Pencil is a trademark of Michael Shrayer Software. * TRS-80 is a trademark of Tandy Corp

tCPM loi Heath. TRS-80 Model 1 and PoyMoiphc 8B13 are modilied mid musl use specially compiled versions ol syslem and applications sollware

ffi) MDiMii.'il viTMun .iwiilable lor use Willi CP M as 1 mplmm'iited

on Heath and TRS-80 Model I compulers

n Z80 DEVELOPMENT PACKAGE - Connsts of '" (1) disk die line editor, wilh global inter and mlra-line facilities; (2) Z80 relocating assembler. Zilog Moslek mnemonics, conditional assembly and cross relerence table capabrlilies; (3) linking loader producing absolute Intel

hex disk file $95$20

D 20T-Z80 Monitor Debugger lo break and examine

lit, registers with siaiiriar^Zilotr-'Mostck mnemonic dis.t:.

sembly displays S3S when ordered with ZHO Develop

rnent Package $50 S10

□ DISTEL — Disk based disassemble; to Inisl 8080 or TDL/Xitan ZOO source code, listing and cross relerence liles. Intel 01 TDL/Xilan pseudo ops oplional. Runs on 8030 $65/S10

D DISILOG — As DISTEL lo Ziloq Moslek mnemonic W dies. Rjns en Z80 only .... „..«.- S65S10

D XASM-68 — Ne-rwuaco Cfg.-.s-.isse-iL"tr- « in nested conditiora's and luu Jaime ol osci-io jctvai.o's Assembles Iroms^ardaifl Maico j MCf^Cn .-i-i<cicrics lo Intel no* >*vfc.|'\^ S200/$25

□ XASM-65 ■ Ah XASM.'tiB "v Mtjs I.-: '-nology MCS6S0O mnem^ffll§»** S200JS25

D TEXTWRITER III — Text formatter lo justily and pagim nale letters and olher documents Special leatures include insertion ol text during execution Irom olher disk dies or console, permitting recipe documents lo be created Irom linked fragments on other liles. Has facilities lor sorted index, table ol conlents and footnote insertions Ideal for contracts, manuals, elc. Now compatible wilh Eleclric Pencil prepared files. S125/S20

Cl POSTMASTER — A comprehensive package lor mail

"*' lisl maintenance. Features include keyed record exlraclion and label production. A form loiter program is included which provides neat letters on single sheet or continuous Iorms. Requires CBASIC-2 S150-$15

LJ WHATSIT?**** Interactive dala-baso system using associative lags lo retrieve information by subject. Hashing and random access used for fast response. Requires CBASIC-2 $125 525

D XYBASIC Interactive Process Conlrol BASIC — Full disk BASIC features plus unique commands :o handle bytes, rotaie and shift, and lo tesl and sel bits. Available in Integer. Extended and ROMable versions,

Inleger Disk or Integer ROMable S295 525

Exlended Disk or Extended ROMable . S395 $25

LJ SMAL/80 Structured Macro Assembled Language — Package ol powerlul general purpose text macro processor and SMAL structured language compiler. SMAL is an assembler language wilh IF-THEN-ELSE. LOOPREPEAT-WHILE. DO-END. BEGIN-END constructs S75/$15

□ SELECTOR I1I-C2 — Data Base Processor to creale ■« and maintain multi Key data bases Prints lormatted.

sorted reports with numerical summaries or mailing labels.Comes with sample applications, including Sales Activity, Inventory. Payables, Receivables, Check Register, and Client/Palienl Appointments, oic. Requires CBASIC-2 Version 2.Supplied in source code S293/$20

□ CPM/374X — Has lull range ol functions lo creale or re-name an IBM 3741 volume, display directory information and edit the data set contenls Provides full lile Iransfer facilities between 3741 volume dala sets and CP.'M files $195'$10

D BASIC UTILITY DISK — Consists of: (1) CRUNCHfwi ]4 _ Compacting utility to reduce the size and increase Ihe speed ol programs in Microsoft Basic and TRS-80 Basic. (2) DPFUN - Double precision subroutines for computing nineteen transcendental lunclions including square root, natural log, log base 10. sin. arc sin. hyperbolic sm. hyperbolic arc sin, etc. Furnished in source on

diskette and documentation $50 $35

P THE STRING BIT — Fortran character string han,Ul dlmg. Routines lo find, fill, pack, move, separate, concatenate and compare character strings This package completely eliminates the problems ' a-ssockilod wi'ih character string handling in FORTRAN Supplied with

source $4S/$15

LJ BSTAM — Utility lo hnkfQpe computer to anolner also " oquipped y^rfH BSWJX/lkiws lile transfers at 'ull data speed (no cpwei&riiTto hex^yJilh CRC block control check for ve>y reiia^^e1:]rJ^eciion And automatic retry. We use it'-lfs^reltL-fiJS wildcard expansions to send * COM. ritr/9M0 baup >*)lVwire. 300 baud with phone connection. Both ^irWb'd'ono Standard and M versions can talk lo one'anolher. Compadble TRSDOS version also available $1 so ss

••••••

SUNDRIES

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□ HEAD CLEANING DISKETTE -- Clear,:-, me drive read/write head in 3G uacends On-l-.'.:!i>- , ilr. or us loose 11. nit-part iclf.-r I iiijier prmli. and other foreicin panicles th.il in.QUI li.n.liu Ihii performance otthi: drive head Lasts at leant 3 month:, with daily use Specify 5" or 8"

S20. n»,, S45. for 3

D Flippy Disk Kit — Template and instructions lo modify single sided Sid" diskettes lor use of second side in single sided drives St 2.50

□ FLOPPY SAVER Protection tor center holes of 5'.*" Iloppy disks Only 1 needed per diskette Kil contains centering post, pressure tool, lough 7-mil mylar remlorcing nngs. Installation lools and rings lor 25 diskettes

$14.95

Re-0'ders ol rings only .. $7.95

□ PASCAL USER MANUAL AND REPORT-By

Jensen and Wulfi.Tfii? standarp lextbookon tne lad guaqe Recommer-rt.'d for jse by Pascal'Z. Pascal'M and Pascal^MT users , $8

D THE C PROGRAMMING LANGUAGE - By Kernighan and Rilchie.. The" Standard textbook on the language. Recommended lor use by BDS C, tiny C, and

hilesmiths C u

$12

******

eboat Associates

tfARE

Orders musl specily disk syslems and lotmafs: e.g. North Star single, double or quad density. IBM single or 2D 256, Allair, Helios II, Micropolis Mod I or II. 5Vj" soil sector(Micro iCOM'SD 5yslems Dynabyte). elc. Prices FOB. New York Shipping, handling and COD. charges exlra

Manual cost applicable againsl price ol subsequent sollware purchase. The sale ol eacf propnelaiy software package conveys a license for use on one system only.

Lifeboat Associates, 2248 Broadway. n.y„ n.y. 10024 (212) 580-0082 Telex: 220501 j^/M^^/j

;;

KTHOME BlTSET

Clearbit

DO IT NOW

Enter Factor ■ Go step Half step Initialize Jog

Leftright Number Onestep Position Quit Bate Slope loop TIL Until

+ CCW) - (CCW)

Tell it

and forget it...

... the new CY500 stored program stepper motor controller runs its own program, freeing your host computer for other jobs.

No more one-pulse, one-step operation requiring your host computer to tie itself down to a stepper motor. Now Cybernetic Micro Systems brings you a function-oriented stored program stepper motor controller that allows the user, or host computer, to program it and forget it...

The CY500 executes 22 hi-level instructions, either in command mode or as a sequence of internally-stored commands, using single byte code such as 'F for position, 'R'for rate, and 'S' for slope. Parameter values can be expressed in ASCII-decimal for keyboard programming or binary code from the host computer. Parallel or serial communication.

The stored program capability allows the use of 'DO-WHILE' program looping and 'WAIT-UNTIL operation. Ten different operational modes allow absolute or relative positioning, fullor half-step operation, hardware or software control of direction, start/stop, . . . and many more.

Numerous input and output control lines allow synchronizing the CY500 with external events or devices and allow each step to be triggered. Stepping at rates up to 3500 steps/sec, the CY500 also provides ramp-up, slew, and ramp-down operation, all under software control.Two interrupt lines request the host's attention if needed.

This +5 volt N-MOS TTL-compatible controller is available from stock, today, for only $95.00. Contact Cybernetic Micro Systems. We want to see you program your stepper motor and then . . . forget it.

Cybernetic Micro Systems

445-203 South San Antonio Road Los Altos, California 94022 (415)949-0666

(Use your MASTER CHARGE or VISA charge card)

Listing 1: Gasuse program for determining mileage, gas efficiency, and keeping track of gas expenses.

10 40 50 110 1010 1020 1030 1032 1035 1037 1039 1040 1050 1060 1070 1075 1080 1081 1082 1083 1084 1100 1110 1115 1120 1124 1126 1130 1140 1160 1170 1190 1195 1200 1210 1220 1230 1245 1248 1250 1252 1255 1260 1290 1900 2000 2010 2020 2030 2050 2080 2090 2100 2110 2120 2130 2150 2180 2190 8100 8110 8111 8115 8120 8150 8160 8170 8180 8190 9400 9404 9406

REM PROGRAM GAS TO FIGURE MILEAGE

REM SCRATCH F"GASUSE"

REM SAVE DC F("GASUSE") "GASUSE"

U$ = HEX(OC)

PRINT " I COMPUTE AND DISPLAY GAS MILEAGE"

ENTER ZERO FOR UNKNOWN FIGURES, I WILL TRY"

ENTER ZERO FOR MILES TO STOP"

ENTER 1. FOR SCREEN DISPLAY" 2. FOR PRINTER OUTPUT"

GALLONS"; DOLLARS'

PRINT '

PRINT '

PRINT

PRINT'

PRINT '

INPUT P9

PRINT

PRINT "STARTING MILES";

INPUT MO

M7=MO

IF P9 = 2 THEN 8100

PRINTUSING 1081

% COST DISTANCE TOTAL AVE TOTAL TOTAL

PRINTUSING 1083

% MILES GAL MILEAGE MILES MILEAGE COST GAL

PRINT

PRINT U$; "NEXT MILES";

INPUT M1

IF M1 =0THEN 1900

IF M1>M7 THEN 1130

PRINT U$;" THIS MILES LESS THAN LAST, OR SAME"

GOTO 1100

PRINT U$;"

INPUT G1

PRINT U1;"

INPUT D1

IFG1 =0THEN 2000

IF D1 =0THEN 2100

REM

M8 = M1-M0

D8 = D8 + D1

G8 = G8 + G1

IF P9 = 2 THEN 8150

PRINT U$;

PRINTUSING 1252,M1,D1,G1,M1-M7,(M1-M7)/G1,M1-M0;M8/G8,D8,G8

%###### $§#.#§ ##.# ### ##.# ##### ##.# »##.## ###.#

PRINT

M7 = M1

GOTO 1100

STOP

PRINT U$; " GALLONS ENTERED AS ZERO, ENTER CENTS/GALLON";

INPUT C1

IF D1=0THEN 2080

G1 =D1/(C1/100)

GOTO 1200

PRINT U$; " DOLLARS ALSO ZERO, NO CALCULATION POSSIBLE";

GOTO 1100

PRINT U$;

INPUT C1

D1 = G1*(C1/100)

IF D1 =0 THEN 2180

GOTO 1200

PRINT U$;" CALCULATION RESULT IS ZERO; REENTER "

GOTO 1100

SELECT PRINT 215(80)

PRINTUSING 1081

PRINTUSING 1083

SELECT PRINT 005(64)

GOTO 1084

SELECT PRINT 215(84)

PRINTUSING 1252,M1,D1,G1,M1-M7, (M1-M7)/G1,M1-M0;M8/G8,D8,G8

SELECT PRINT 005(64)

PRINT U$;TAB(64)

GOTO 1260

DEFFN'O "LISTS"

DEFFN'1 ",9999"

DEFFN'2 "000,9999"

DOLLARS ENTERED AS ZERO, ENTER CENTS/GALLON'

TOTAL

AVE

TOTAL

TOTAL

LES

COST

GAL

DISTANCE

MILEAGE

MILES

MILEAGE

COST

GAL

1202

$4.19

7.5

201

26.8

201

26.8

$4.19

7.5

1453

$5.75

10.1

251

24.8

452

25.6

$9.94

17.6

1604

$2.59

5.0

151

30.2

603

26.6

$12.53

22.6

1715

$3.45

6.2

111

17.9

714

24.7

$15.98

28.8

1995

$3.95

6.9

280

40.1

994

27.7

$19.93

35.7

Table 1: Sample output from listing 1. To determine accurate gas usage take an average over several results.

Circle 52 on inquiry card.

Stanley's office staff says Stanley always stays one step ahead. So no one was surprised when he showed up with Microsoft's COBOL-80 for the office computer. That's when things started happening.

As Stanley explains, "Suddenly, the whole business operation is more efficient. I use it for everything: inventory, payroll, record keeping, customer and employee files. Since COBOL is the standard language for business and commercial applications, more programs are written in COBOL than any other language. Believe me, nothing beats it in terms of powerful use of disk files, data manipulation facilities and interactive terminal communications!'

Stanley added loudly, "And that's versatility and efficiency I'd like to see more of around here.

"My COBOL-80 package from Microsoft includes the MACRO-80 assembler, LINK-80 linking loader and LIB-80 relocatable library manager. I can even call FORTRAN, BASIC, assembler and COBOL modules from a COBOL80 program. It's perfect—a total software development package',' exclaimed Stanley.

Microsoft's COBOL-80 is an ANSI-74 standard COBOL that supports such advanced data manipulation verbs as COMPUTE, INSPECT, STRING, UNSTRING AND SEARCH: threedimensional arrays; full COPY facility; and com

plete screen handling capability. The optional packed decimal format saves on mass storage by as much as 40%. And as Stanley puts it, "With my floppy disk system, that's a big plus!'

Stanley can't say enough about his new addition to the office. "COBOL-80 supports indexed and relative files, including DYNAMIC access, FILE STATUS, START, READ NEXT, DELETE and REWRITE. Best of all, interactive ACCEPT/ DISPLAY gives the most powerful screen handling capability possible.

"Frankly!' says Stanley, "Microsoft COBOL80's performance is so superior it's set a whole new standard of efficiency for my staff. My new motto? 'Shape up or ship out! Thanks Microsoft, my office will never be the same!'

The COBOL-80 package for the CP/M or ISIS-II operating system with documentation is $750. Documentation may be purchased separately for $20.„Dealer purchases and OEM license agreements available on request.

urn

10800 N.E. Eighth Suite 819 Bellevue, Washington 98004 206/455-8080 Telex 328945

We set the standard.

FI

Circle 53 on inquiry card.

Programming Ouickies

String Comparator for Horizon

Richard W Lindberg, 9302 Mayrene Dr, Garden Grove CA 92641

As a recent purchaser of a personal computer, and an even more recent subscriber to BYTE, I look for programming articles to help expand the horizon of my Horizon. I scanned the September 1979 issue as soon as it arrived, and was intrigued by the article "A Similarity Comparator for Strings," by T C O'Haver on page 58. Realizing changes would be necessary, I immediately set out to translate it to run in North Star BASIC.

The first change required was the replacement of the string operator MID$(A$,I,1) with A$(I,I) in statements 130, 140, 230, and 240. (Note that North Star also allows

Listing Is Similarity comparator program in North Star BASIC, adapted from the program by T C O'Haver.

8

DIM A$(64),B$(64),Z$(64),A1$(64),B1$(64)

10

T = 0

20

P = 3

30

F'FIRST WORD",

40

INPUT Al$

50

A = LEN(A1$)

55

A$(1,A) = A1$

60

("SECOND WORD",

70

INPUT Bl$

75

IF A1$ = B1$ THEN !"EXACT MATCH"

80

B = LEN(B1$)

85

B$(1,B) = B1$

90

IFA>BTHENB = A

100

FOR M = 1 TO B

110

C = 0

120

FOR 1=1 TOM

130

K$ = A$(B-M + I,B-M + I)

140

L$ = B$(I,I)

150

IFK$ = L$THENC = C + 1

160

NEXT I

170

C = CtP

180

T = T + C

190

NEXTM

200

FOR M = B + 1 TO 2*B-1

210

C = 0

220

FOR 1=1 TO 2*B-M

230

K$ = A$(I,I)

240

L$ = B$(M-B + I,M-B + I)

250

IF K$ = L$THENC = C+1

260

NEXT I

270

C = C1P

280

T = T + C

290

NEXTM

300

S=100*T/BtP

310

!S,"%"

320

T = 0

325

B$ = Z$

330

GOTO 70

340

END

the implied LET and the use of ! for PRINT.) The next change was the addition of a DIMension statement to allow strings greater than 10 characters in length. Then when trying to compare two strings of different length, the computer threw me out! This necessitated having enough blanks in the shorter string to match the length of the longer one. To accomplish this, strings A$ and B$ were set to 64 blanks by the dimension statement, and temporary strings Al$ and Bl$ were used to read in the input string data and compute the lengths A and B. Al$ was then placed in the first A characters of A$, and Bl$ in the first B characters of B$, leaving the remaining characters blank. Blank string Z$ is used to reset B$ to blanks before testing a new string, otherwise there would be unwanted characters left in B$ if the previous string were longer than the new string. This was noticed when I followed O'Haver's test sequence, and found that POO gave a 100% match with POOL, because the previous test string was COOL and the L was still there. So with the addition of line 325,1 knocked the L out of it and had the program running. The address strings took many seconds to run.

Listing 1 gives the program as adapted to North Star BASIC Version 5.0, and listing 2 shows a sample run for comparison with the published run. Note that the agreement is quite good except for POOL ROOM, MAIL ROOM, and the long address strings. These differences are possibly due to the addition of the trailing blanks to fill the shorter string. A speedier version would be even more useful, and I am looking forward to the assembly language version — who would like to write it?

Listing 2: Two sample executions of the program in listing 1.

RUN

FIRST WORD ?POOL SECOND WORD ?POOL EXACT MATCH

103.125% ?POOR

45.3125% ?COOL

45.3125% ?POO

45.3125% ?POLO

28.125% ?LOOP

18.75% ?PAIL

12.5% ?POOL ROOM

20.164609% ?MAIL ROOM

3.0178326% ?PO/OL

14.4%

?oooo

40.625%

RUN

FIRST WORD ?T.C. O'HAVER 710 HILLSBORO DR. SILVER

SPRING MD.

SECOND WORD ?TOM O'HAVER 710 HILLSBORO DR. SILVER

SPRING MD.

77.241074% ?R.D. O'HAVER 710 HILLSBOROUGH RD. SILVER SPRINGS FL.

14.492063% ■

86 February 1980 © BYTE Publications Inc

APPLE OWNERS

EXPAND YOUR SYSTEM

WITH 8" FLOPPY DISK

FROM WIZARD*

WIZARD

Many software programs are restricted by the 1 1 6 K available on the 5" disk drives now on the market. Some business programs require 1 2 or more diskettes, which can be both confusing and error inducing.

WIZARD offers four solutions:

'•WIZRRD\ + 1": single 8" drive system; 256 K $1695.

'WIZARD 2 + 2" : two 8" drive system; 516 K $2495.

"WIZARDPLUS" : two 8" drives, double sided; over 1 megabyte $3150.

"WIZARD 1 0" : 1 0 megabyte Winchester drive, formatted as one file. $4795.

All systems are ready to run, fully assembled and tested, and include:

SHUGART full size 8" floppy disk drive(s).

Controller Card for your Apple (48K RAM required)

All interface software, cables, connectors, cabinet and power supply.

ONE YEAR parts and labor warranty from defects in material and workmanship.

WATCH FOR NEW WIZARD PRODUCTS FROM D&T ELECTRONICS: we are currently developing other hardware and business software.

ALL SYSTEMS AVAILABLE NOW (stock to two weeks). SEE YOUR LOCAL APPLE DEALER, OR CONTACT THESE WIZARD DISTRIBUTORS:

MAR-COMP COMPUTER DISTRIBUTORS, INC.

175 East Edgewood Drive PO BOX 9194

McMurray, PA 15317 Austin, TX 78766

(412)531-5445 (512)345-9729

DEALER INQUIRIES INVITED

SOFTWARE: We have software available to run on these expanded capacity systems; please send for our list.

If you are a software writer and have programs currently on 5" that would benefit from the expanded capacity of our 8" systems, we would like to hear from you.

WIZARD is a registered trademark of D&T Electronics, Inc. Apple is a registered trademark of Apple Computer, Inc.

Circle 54 On inquiry card. BYTE February 1980 87

Blubs and Newsletters

Sorcerer User's Group in Ann Arbor Ml

The Sorcerer User's Group and their newsletter, The Sorcerer's Apprentice, are based in Ann Arbor MI. The group meets once a month at the Newman Computer Exchange and the newsletter is printed every month and a half. The group's object is to spread Sorcerer-related information to all owners and to get as much out of the machine as possible. Contact Dave Bristor, 1530 Washtenaw, Ann Arbor MI 48104.

Computer Group for Medicine and Science

Microcomputers in Medicine and the Sciences

Association is an organization devoted to aiding members of the medical and scientific communities gain working knowledge of computers and their uses in research and practical applications. Meetings are accredited seminars covering languages and applications of microcomputers. They meet in the Chemistry Building, Rm 105, University of South Florida, Tampa FL, on the fourth Thursday of the month at 7:30 PM. Their newsletter is called MI MSA News.

Software World

Called the Software World, this quarterly publication from England contains programs, book

computer mart of n»w j»rs»y

[Computer Mart of New Jersey

501 Route 27

Iselln, N.J. 06830

(201)283-0600

HOURS,

Open ot 10 am,

Tuesday through Saturday

the

microcomputer

people®

THE VITAL INGREDIENT:

EXPERTISE

Before you buy your new microcomputer, chances are you hove a lot of questions. Important questions that could mean the difference between a working system and a wasted system. The vital Ingredient Is expertise. The microcomputer people at Computer Mart are expert at answering your questions and helping you put together the best system for your application. Whether It's for business, the home, or the laboratoryi come see the experts at Computer Mart of New Jersey. We have the vital Ingredient.

reviews, new products, and computer related business items. The subscription rate in the US is $64 a year. The newsletter is one of a series of three software related publications from A P Publications Ltd, 322 St John St, London EC1V 4QH ENGLAND.

Compucolor User's Group

The Canadian Compucolor User's Group meets on the second Wednesday of every month and invites users as well as interested onlookers to join and utilize the program library. For more information, contact House of Computers Inc, 368 Eglinton Ave W, Toronto, Ontario M5N 1A2 CANADA.

Club 1802 Newsletter

Club 1802 is a newsletter published for users of microcomputers which are based upon the 1802 processor. Programs, book and program reviews, want ads, items for sale and letters on related subjects are included. The newsletter is published twelve times a year and current rates are scheduled to be about $10 a year. For more information, contact Club 1802, POB 985, Dickinson TX 77539.

Apple Dayton

This Apple II users group alternates their meeting dates between the second Wednesday of odd numbered months and the second Thursday of even numbered months to allow different people to attend at least bi-monthly. Meetings are held at Computer Solutions, 1932 Brown St,

Dayton OH, at 7:30 PM. For more information, contact Apple Dayton, Robert W Rennard, 2281 Cobble Stone Ct, Dayton OH 45431.

Sorcerer User's Group Newsletter

The Exidy Monitor is a monthly newsletter intended for users of Sorcerer microcomputers. The newsletter contains programs and other technical articles plus a software library buyer's guide for members and nonmembers. For information, write to The Exidy Monitor, c/o Computer Mart of Massachusetts, 1395 Main St, Waltham MA 02154.

Computer Club in Central Nebraska

Compusers is a new club for anyone interested in computing, particularly owners or prospective owners of microcomputers of any make. Meetings are held on the third Monday of each month at 8 PM. Dues, by-laws, and permanent officers are not yet established. For more information, contact Rocky Friend, POB 2064, Hastings NE 68901. Their monthly newsletter is also available from the same address.

West German

Microcomputer Club for

Radio Amateurs

The DAFG/GART German Amateur Radio Teleprinter Group has 1300 members who use SDK-85, KIM-1, PET 2001, TRS-80, Apple II, and other microcomputers for amateur radio operation in RTTY, FAX, SSTV, or CW. The membership fee is DM 35.00 annually. The newsletter, RTTY, is published six times a year. For more information, contact Manfred N May, Herrenstr.56, D 5014 Kerpen-Sndf. Or contact R F Matthaei, Beisserstr.45, D 2000 Hamburg-63, uCReferat, WEST GERMANY.

88 February 1980 © BYTE Publications Inc

Circle 55 on inquiry card.

L

11

SO RELIABLE WE GIVE YOU

f

355 356 357 358 359

350 351 352 353 354

345 346 347 348 349

340 341 342 343 344

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330

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325

326

327

328

329

320

321

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323

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315

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225 226 227 228 229

TOTAL PEACE OF MIND.

We are business people, just like you. We wouldn't stick our neck out unless we were certain we could back our claims and promises to the last letter. We wouldn't offer a legally binding long-term warranty on our Microtek MT-80, unless we were positive of its solid reliability.

We are sure that our versatile, alphanumeric line printer will provide you consistent, dependable performance. This is why we give you, not the usual 90-days in fine print, but an incredible 365-days warranty. We stand behind every product we make.

LOADED WITH INNOVATIONS

• 40, 80 or 120 columns (software selectable)

• Non-thermal paper, pin feed

• 125 CPS, 70 lines per minute

• 9 x 7 dot matrix

• Vertical format unit

• 96-character ASCII (upper and lower case)

• Adjustable forms width to 9 Vs>"

• Parallel, serial (RS-232C), and IEEE-488 interfaces available

OUR UNIT PRICE

$750. Parallel

$835. Serial (RS-232C)

$895. IEEE-488

For more information contact:

MICROTEK, Inc. 7844 Convoy Court San Diego, CA 92111 Tel. (714)278-0633

Circle 56 on Inquiry card.

Free Newsletter on

Process Instrumentation

Systems

A newsletter series entitled ControLoops covers the fundamentals of industrial process instrumentation and control systems. Theory and implementation on unit control systems including cascade control, auctioneering, and feedforward control, plus application diagrams are featured in the series. For a free subscription to ControLoops, contact E Ross Forman, Manager — Instrumentation Engineering Group, Day and Zimmermann Inc, 1818 Market St, Philadelphia PA 19103.

PAX (Program

Analysis Exchange)

Succeeds 52-Notes in

a New Format

PAX is a publication devoted to the analysis and evaluation of widely used personal computing softwa

currently on the public market for which good supporting documentation is not known to exist. Back issues of PAX and 52-Notes are available for $1 each. Write to Richard C Vanderburgh, 9459 Taylorsville Rd, Dayton OH 45424, to obtain information on contributing articles.

Ontario Society for

Microcomputers in

Education

A group of seventy educators have started the Ontario Society of Microcomputers in Education in order to coordinate individual efforts and provide a clearinghouse for the exchange of information on equipment, curricular materials, and teaching methods. The group's aims are to promote the use of microcomputers in all aspects of education, share knowledge of hardware and software, develop strategies for demonstrating the uses

of microcomputers in the classroom, to assist in the development of software to meet specific curricular needs, and more. For more information, contact N Solntseff, Unit for Computer Science, McMaster University, Hamilton, Ontario, L8S 4K1 CANADA.

International Computer Club

The International Society of Personal Computerists was organized to promote and advance personal computing on a world-wide basis. The society's services include free software, free consultation, custom programming, conversions from one BASIC system to another, and group discounts on software and hardware purchases. TidBits, the newsletter, is of broad general interest to computer users and hobbyists. The society publishes several other newsletters

tailored to Apple users, Heath users, TRS-80 users, beginners, and nonusers. Membership is $15. Contact International Society of Personal Computerists, 4554 Cristy Way, Castro Valley CA 94546.

Southern New Hampshire Apple Group

The Southern New Hampshire Apple Core meets once a month. The group is dedicated to Apple users, and they currently have plans to give public demonstrations of computers. Their newsletter is entitled SNAC Facts and it contains information concerning the meetings, items of general interest, and short programs. The members are building a disk library and are interested in hearing from other Apple users. Dues are $6 per year. For more information, contact SNAC, Computerland of Nashua, 419 Amherst St, Nashua NH 03060. ■

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90 February 1980 © BYTE Publications Inc

Circle 57 on inquiry card.

TEX and

by Donald E

l|> and MKIAKOM

METAFONT, New Directions in Typesetting

Knuth

TEX and METAFONT,New Directions in Typesetting describes two systems that are going to change the typesetting/publications world. TEX is a system for typesetting technical text currently being implemented in PASCAL. It is in the public domain and is available to all who are involved in computerized typesetting. METAFONT, a system for design of alphabets suited to implementation on raster-based devices, permits a designer to give a completely precise definition to an infinite variety of typefaces. TEX and METAFONT are unique and powerful achievements whose concepts will be useful to: authors and publishers; programmers and system designers in typesetting, graphics, and office automation; typeface designers and commercial artists; compositors; university computing centers; and manufacturers of typesetting equipment. Foreword by Gordon Bell. A co-publication of Digital Press and the American Mathematical Society. 1979, 360 pp., ISBN 0-932376-02-9, paperback, $12*.

Data Processing Technology and Economics, Second Edition

by Montgomery Phister, Jr.

Data

Processing

Technology

and Economics

Data Processing Technology and Economics, Second Edition, is a comprehensive study of the data processing industry from its inception through 1978-79. It provides quantitative data and insightful narrative on four topic areas: the marketplace, products, applications, and costs. Coverage includes operating costs (to the user) and development, manufacturing, marketing, and maintenance costs (to the supplier). Other topics include hardware and software reliability, computer (and peripheral) population, system performance with multiprogramming, software performance and usage, I/O technologies and costs, computer use by industry and government, principal applications, human performance factors, and the important computers. Data Processing Technology and Economics is for users, applications programmers and systems analysts, system programmers, hardware designers, and managers. A co-publication of Digital Press and the Santa Monica Publishing Company. 1979; 736 pp.; hardbound (ISBN 0-932376-03-7), $29.95*; paperback (ISBN 0-932376-02-9), $24.95*.

Computer Engineering: A DEC View of Hardware Systems Design

by C. Gordon Bell, J. Craig Mudge, and John E. McNamara

Computer Engineering: A DEC View of Hardware Systems Design is the story of hardware systems design practiced at Digital Equipment Corporation from 1957-77. It provides a set of case studies of classic design principles and techniques practiced under the real-world constraints of marketplace economics and continually evolving technology; an overview of the computer industry—insight into the complexities of its interrelated forces and an historical perspective; and a description of the development of families of machines. Computer Engineering is for people who want to understand the evolution of hardware systems design: hardware systems designers, university students (used in computer architecture courses at Caltech and UC/Berkeley); management of companies planning systems or planning to buy systems; software engineers; users. 1978, 585 pp., ISBN 0-932376-00-2, hardbound, $19.95*.

Technical Aspects of Data Communication

by John E. McNamara

QDIDDSD

Technical Aspects of Data Communication provides a practical approach to the nuts-and-bolts problems and solutions in configuring communications systems. It describes common pitfalls in systems design and ways to avoid them, while also serving as a useful reference tool. Technical Aspects of Data Communication is intended to fit between books that treat data communication solely on a system level and hardware manuals that specify in detail the function of each bit in each register. The book features: comparison of protocols (DDCMP, BISYNC, SDLC), extensive explanation of interface standards (CCITT/V.44, RS232C, RS422, RS423) comprehensive appendices (how far —how fast?, modem options, codes (Baudot, ASCII, and others), UART, format and speed table for asynchronous communication, channel conditioning). Other topics covered are the 20-milliampere loop, telephone switching systems, error detection, and digital transmission and packet switching networks. 1977, 382 pp., ISBN 0-932376-01-0, hardbound, $19.95*.

Digital Press, Educational Services

Digital Equipment Corporation

12-A Esquire Rd., Billerica, MA 01862

ORDERING INFORMATION

'Prices are U.S. only. (Contact your nearest office of Digital Equipment Corporation, Educational Services for prices outside U.S.) Ten percent discount for two or more copies. Shipping and handling charges will be added to all orders not prepaid.

Please specify number of copies:

TEX and METAFONT, New Directions in Typesetting

Data Processing Technology and Economics, Second Edition

□ hardbound □ paperback

Computer Engineering: A DEC View of Hardware Systems Design

Technical Aspects of Data Communication

□ Check enclosed. □ Please invoice me. (Specify billing address if different

from shipping address.) Remit to: Dept.DPC, Digital Press, at the address above.

Circle 58 on inquiry card.

BYTE February 1980 91

Implementing Dynamic Data Structures with BASIC Files

Ted Carter

902 Pinecrest

Richardson TX 75080

In many computer applications where a large amount of information is to be stored, the need arises to sort, insert, and delete items efficiently using random-access tape or diskbased files. A common method of implementing a mailing list, for example, is to add new names to the end of the current file and to delete names by putting a blank field in place of the names to be deleted. This minimizes the number of time-consuming reads and writes to the file.

However, when this mailing list has to be printed in zip-code order, for example, the task becomes extremely slow as the number of names increases. This is because the number of file accesses increases exponentially with the number of items to be sorted. One possible solution is to actually sort the file so that it is always in order. This is impractical because it necessitates the same sort operation as before, plus a complete rewrite of the file.

With close examination of the problem, you might decide that the file should always be kept in order by inserting a new name in its proper place. This is a good idea, but requires that you must move, on the

About the Author

Ted Carter is employed at the Texas Instruments Corporate Engineering Center. In 1978, he founded Software Industries, a custom software house. His interests include computer speech synthesis and computer automation.

average, N/2 names (for a file of N names) to make room for the new names. Again, with large files, this may take an inordinately large amount of time.

In order to solve these problems successfully and efficiently, you need a data structure that will permit an insertion and deletion of components without having to worry about where new components fit or what happens to the empty space left by deletion. The tool needed to create such a structure is called a pointer. This is simply a number that points to the location of a desired piece of data. Using disk files, for example, a pointer to a piece of data is its actual record number on the disk file. This takes advantage of the random access capabilities of a disk file so as to directly locate and read the data using the pointer value.

Using pointers, a linked list, the simplest type of dynamic data structure, can be built. In order to build the linked list, every data record must

be accompanied with a pointer to the next element in the linked list. Therefore, space must be reserved in the file for a pointer value within each data record.

A linked list is shown pictorially in figure 1. In a disk file, for example, you could store the base pointer value in the first record of the file. However, you need some way of knowing that the last data item Z does not point to anything. This can be accomplished by storing some special number not in the range of possible pointer values, such as zero, as the pointer value associated with the last data item. An important thing to realize is that records X, Y, and Z can physically be in any order on the disk. However, they are linked in order and can be retrieved in order with absolutely no comparing or sorting.

Record insertion is also relatively simple. The ordered list is scanned until the element to be added is greater than or equal to the current

Figure 1: Example of a linked list. In this picture, X, Y, and Z are records containing the information that is to be stored. The boxes on top represent a portion of memory connected with each record that contains the address of the next record in the list. These are called pointers. The first record in the file, called the base record, points to the first data record in the file but does not contain data itself. This is because the base record also contains a pointer (not shown) to the first available space for new records.

92 February 1980 © BYTE Publications lnc

THE

INFLATION

FIGHTE

You can't buy more capability for less ... But you can buy less for more

Circle 59 on inquiry card.

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BYTE February 1980 93

TRS-80, Apple II and S 100 owners.

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BYTE, January 1980

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TRS-80 is trademark of Tandy Corp. Apple II is trademark of Appie Computer

The number of file accesses

increases exponentially

with the number of items

to be sorted, iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiin

element and less than the next element in the list. The new element is then inserted between these two elements. For example, assume that Y2 is to be inserted before Z and after Y, as in figure 2a. This is achieved by placing Y2 physically in the first free position on the file, making Y2 point to where Y pointed, and making Y point to Y2, as in figure 2b.

The process of deleting an element is easier. Consider deleting Y2 from the list in figure 2b. By making Y point to where Y2 pointed before Y2 was deleted, the result is the list in figure 2a.

In some situations, an improvement on the linked-list data structure is the doubly linked ring, shown in figure 3. With this structure, you may

BASE

scan from either direction, often facilitating an insertion and deletion either before or after an element. For ease of explanation and understanding, a simple singly linked list as in figure 1 will be used in the examples given in this article.

Implementing the Linked List

When implementing a linked list using random-access files, some additional problems must be solved. An element can be inserted in the linked list easily enough, but the computer must know where the first empty disk file 'is located. Secondly, when deleting an element, the disk file location of the deleted record should be recovered for later use.

These problems could be solved by marking the record to be deleted and later searching for the first empty or marked record when adding a new element. A much better solution is to create a linked list of free records. When adding a new element, a record is taken out of the linked list of free records and inserted in the ordered

2a

X

BASE

2b

Y2

•

X

Y

Z

Figure 2: The process of insertion in a linked list. Figure 2a shows a new record, Y2 (probably physically located after nodes X, Y, and Z), before it is linked into its proper place in the list. To link it into the list, as in figure 2b, only the pointers in Y and Y2 must be changed.

BASE

Figure 3: Example of a doubly linked ring. In this kind of linked list, each record contains a pointer to the previous as well as to the next record in the list. This has certain advantages in some applications, although it creates more memory overhead in each node. Doubly linked lists are not discussed in this article.

94 February 1980 © BYTE Publications Inc

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The board is very similar to the PLUS card. It differs in that its bank select can use any of 256 output port addresses and it can be addressed on 16K boundaries only. Pricing is the same as for the PLUS.

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This board was designed for the 1980s. It is configured as 16K by 8 bits when accessed by an 8-bit processor and configured 8K by 16 bits when used with a 16-bit processor. The configuration switching is automatic and is done by the board sampling the "Sixteen Request" signal sent out by all 16-bit processors. The board has all the high noise immunity circuits of the PLUS and APEX as well as "extended addressing". Extended addressing is a replacement for bank select and makes use of a total of 24 address lines to give a directly addressable range of over 16 megabytes. This card ensures that your new memory purchases will not be soon obsoleted. It comes with 250 nsec. chips only and is guaranteed to run with our 8086 with an 8 Mhz. clock. Prices: 1-4, $445; 5-9, $345.

MEMORY CHIPS

From time to time we have surplus 4044 type 4K by 1 memory chips. Call for current availability and price.

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There are two ways to go. You can check with your local dealer or order direct from the factory. Bank cards, personal checks, CODs okay. There is a ten day return privilege on factory orders. All boards are guaranteed for one year—both parts and labor. Shipped prepaid from stock.

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BYTE February 1980 95

THE TRAP DOOR

September 1977

■

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These prints are strictly limited to a quantity of 750 for each cover, and no other editions, of any size, will ever be published. Each print is 18" x 22", printed on quality, coated stock, and signed and numbered in pencil at bottom.

The price of each print is $25. This includes 1) a signed and numbered print; 2) a Certificate of Authenticity, also signed personally by the artist and witnessed, attesting to the number of the edition (750), and the destruction of the printing plates; and 3) first class shipment in a heavy-duty mailing tube.

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Listing 1: Program to create a linked list file. This program, written in CBASIC, creates a small file that contains forward pointers to the next available record. The first record, which is initialized to "2,3", points to the first data record in the file (record 2) and to the first empty (available) record in the file (record 3). The second record, initialized in line 25, is a sentinel record that denotes the end of the file. It is always the last data record in the file and has a forward pointer of zero.

jEFATE A FILE WITH A LINKED LIST OF FREE RECORDS

REM

REM

REM

REM

RFM

RR'M

E'EM

EEM

REM

REM

REM

REM

REM

REM

-There i.j i i i be 10 free records in the sample file,

FILELENGTH=10

-Create the file with a record length of 22- give -it the file number of one.

CREATE "ClATA.FTL" REEL 22 AS 1

-Eu t bo ir.ter i n f or the - dei- e d 1 i n ke d da ta lis I

-an d l i s t o f fret' records,

PRINT #1! 2-3 ■-Rut ser.tenial with highest possible value at end -of l i nked list ..:. f data.

PRINT 1*1. ! 0, "72ZZEZZ7 Z3J!7.r"

-Create the linked list of free records lv, mdkina -each one Point to the n«vt record.

FOR Z=4 TO FILELENGTH-l-2 : PRIN'i 1*1 : 7, < "" : NEX1 -Make the last free list record pointer equal -zero to signify the end of the list.

PRINT #1! 0,""

CLOSE 1

Listing 2: Program to add a record to a linked list file. This program uses the forward pointers to chain through the linked list until the proper place for the new record is found. The only pointers that need to be changed are those on the record being added and the record immediately preceding it.

EM EM EM EM EM

TEI UIH

IS PROGRAM ADD: 1LE KEEPING IT

SOME ALF*HANUMER IN ALPHABET .1 CAL I

DA WEfi

PEM

REM--G

IN

-Le NE

REM—

PO I

EMEM—

40 45

EMEM

60 65

7 0

til TR( PO IE In! -af ■ REM— REM—

REM— REM—

REM—

REM— REM — REM—

M "DATA. POinter

D # i. 1: NEXTFREE

data to I.JT"New d t J u s 11 f PATA*=LE

p o i n t e rNTER=BA r c h 1 o o p d the pp ILPOINTE MTER=NEX NEWDATA* ert ou er the e Get the t a k i n 9 a READ # 1 , If TRAIL be modi. < IF TRAIL PRINT #1 PRINT #1 Mom take PRINT #1 No in make p o i n f e d p o i n t e d PRINT #1 PRINT #1 CLOSE 1

ed REE

#1 with record tenet

EIL" REEL 22 AS 1 S to start of I ml BASEPOINTER- NExTP =0 THEM PR I NT"File is

a d d . ata:"5NEWDATA* v data in a f i e I d o f b FT*(NEWDATA*+" 5 to start of list. EPOINTER : MEXT POINTER

m h i c h t r a v e r s e s t h e 1 0 p e r p 1 a c e f o i n s e i ■ t t R=--pO INTER : PREVDATA*-TPOINTEP : READ iU,POI

DATA* THEN 40

ists

f ij 1 1

= BA i n t. e he r, DATA NTER

EP

1. 1.4 i

SINTER

list t ■: data .

nextpointer,daT*

NEWOATA* 1 e merit p.; place to record i NEXTFREE!

l n k . bv

in D, .i n t e d

physical 1v u t o f t h e \MEXTRECOED P 0 IN T E R = P 0 INT ER, t he i e d i n o r d e r t o a d d POINTEROPQINTER THE -1; NEXTFREE- NEXTRE -MEX TFREE: BASEPOIN T

record out of free ,1; BASEPOINTER- MEX

11. e new i t e m p o i ri t to bv TRAILPOINTER p to bv TRAILPOINTER p -MEXTEREE; POINTER, , TRAILPOINTER; MEXT'F

ills TRAIL

.it th

?e 1 i

the t f h e

75 3RD v, NE inked ;ECOR :■, in h e i nter i. n t t ;WDAT £E- P

INTER.

ne 1.1.1 re e d lis

t.

i n t«

L r, Si .

ATAS!

I 1 5 t .

? the r make t n e uj 11 •

:rWDATA*

he re

list. When deleting a record from the ordered list, the record that has just been removed is added to the linked list of free records so that it can be used the next time an element is to be added.

The following example uses linked lists and random-access files. For the sake of simplicity, assume that each record consists of one pointer to the next record in the list and one string of data. Since there are two linked lists, the first logical record will contain two pointers, one to the first data element, the second to the first free record.

The program of listing 1, written in CBASIC, creates a data file capable of holding ten data entries of fourteen characters each. The file created by this program is shown in listing 5a. Notice that data record number two, the first in the linked list of data, has a zero for its forward pointer and is filled with "z"s, the highest possible data going in alphabetical order. Such a dummy record, usually called a sentinel, will always be the last element of the linked list. The sentinel is also used to locate the end of the linked list when the linked list is traversed in ascending order. Although programs can be written without the sentinel record, the sentinel greatly simplifies them.

The program of listing 2 adds a record to the linked list. It gets the data to be added and scans the linked list (keeping a pointer to the previous record) until the record to be added is alphabetically less than the one being read. When this occurs, the new item should be added immediately before the one being read. This is accomplished by making the new record point to the record being read and making the previous record point to the new record. When inserting a new item at the very beginning of the linked list, a special case exists that must be accounted for, since the base pointer in the first record must be changed to point to the new record.

Listing 5b shows what the data looks like after adding a piece of data named "First item". Listing 5c and listing 5d show the contents of the file after the addition of several new entries to the file. Note that the path of the linked list is such that the data is always in alphabetical order.

98 February 1980 fe) BYTE Publications Inc

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Listing 3: Program to list a linked-list file. This program uses the forward pointers to print out the records in the order in which they are encountered. This example corresponds to printing out the data fields in ascending alphabetic order.

REM THIS PROGRAM LISTS OUR ALREADY SORTED FILE.

REM

REM—Open tile #1. with record length of 22. 10 OPEN "DATA.. FIL " RECL 22 AS 1

REM—Set pointer to start of linked list, 15 READ ftl,I! POINTER

REM—Loot" to traverse list and print data

REM—until POINTER is zero. 20 READ #1,POINTER; pnINTER,DATA* 25 IF POINTERO--0 THEN PRINT DATA* : GOTO 20 30 CLOSE 1

Listing 4: Program to delete a record from a linked list file. This program deletes a given record by changing the pointer of its previous record. The pointers in record 1 and the deleted record are changed so that this record is the first record of the linked group of free (available) records.

REM

DELETE A Di

REM REM REM

ADD IT TO i

REM-

-Open file :

1 0

OPEN "DATA

15

INPUT"Data

RE11

-Left justi

20

DATA*=LEFT

R'EM

-Set points

25

READ #1,1:

30

POINTER=Bfi:

REM

-Search loo

REM

-finds a ma

35

TRAILPOINTI

40

POINTER-NE

45

READ ttl,PO

50

IE NEXTPOI

55

IF DATAIN*

REM

-Delete the

REM

- r e r o r d P o i

REM

-after the

60

IF TRAILPO ELSE PR

REM

-Add the noi

REM

■- f r e e 1 l n k e

65

PRINT #l,pi

70

PRINT #1,1

75

CLOSE t

DATA ITEM FROM OUR MAIN LINEED LIS! AMD rO OUR LINKED LIST OF FPEE RECORDS.

#1 with record length of 22, .FIL" RECL 22 AS 1

to delete: ": DAT AS, f v d a t a in a f 1 e 1 d of 11 a nks. *<DATA*+" ".14)

r s t o be 9innins o f 1 i nke d list

BASEPOINTER, NEXTPREE SFPOINTER: NEXTPOINTER=BASEPOI p t r a v e r s e s t h e 1 i n k-e d 1 i s t u n tch or runs oi.it of data, ER=POINTER: PRCVDA7A*=DATAIN* XTPOINTER

I NTER: NE X "1 PO T NTER, DATA I N4 NTER-0 THEN PRJNT"No match hxi ■ODATA4 THEN 35

record pointed to bY POINTER nted to hv TRAILPOINTER point one pointed to by POINTER. IN"1ER=P0INTER THEM BASEPO I NTER INT #1, TRAILPOINTER: NEXTPOINT ui u n u s e d r e c o r i J p o i n t e d t o b t d list.

01NTER: NEXTFREE,"" : BASEPOINTER, POINTER

NT El

t i 1

GOTO

mak the

] n g I: r e c o i

NE ER,

nf.:

■0 [NIL :EVDAT

r- d

R \

A*

the

The program of listing 3 and its output in listing 5e will clarify any confusion in following the list. This program traverses the linked list of data and prints each item out as it is read. It can be concluded, from the brevity of listing 3, that printing a sorted list is much easier with the use of a linked-list file organization.

Listing 4 shows the solution to the problem of deleting a given data item and placing the free space back into the linked list of free records. The program scans the linked list until it reaches the end of the file or finds the data to be deleted. When the data to be deleted has been found, the previous record is made to point to where the deleted record points. As in listing 2, deleting the first item in the linked list results in a special case, and the base pointer must be modified. The deleted record is then added to the linked list of free records. Listing 5f shows the data file after the "Fourth" data item has been deleted. Note the "6" in the first line of listing 5f, which points to the first free record, the record that has just been deleted.

Although the concept of the linked list may be difficult to understand, it is a very powerful tool. If, in the mailing list example, the information needs to be sorted by more than one field, it is simple to create a linked list for each field to be sorted and to make room for the additional pointers.

Other modifications are possible; for example, the linked list could spread over more than one file on a disk or over more than one disk by having the pointers preceded by a

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(312)530-8992

100 February 1980 © BYTE Publications Inc

Circle 61 on inquiry card.

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BYTE February 1980 101

Listing 5: Examples of linked list files. The contents of the file created by listing 1 are shown in listings 5a, 5b, 5c, 5d, and 5f. In each case, the records are numbered 1 through 12, with record 1 at the top. Listing 5a shows the contents of the file just after it has been created by the program in listing 1. Listings 5b, 5c, and 5d show the file after one, two, and five records, respectively, have been added. Listing 5e shows the result of running the program of listing 3. The data appears listed in ascending alphabetic sequence. Listing 5f shows the file after the fourth node has been deleted. Note that the available record pointer in record 1 points to line 6, the location of the line that has just been deleted.

(5a)

(5c)

1 0,

1 1 , 1 2,

0, ZZZZ3Z! 2 zzzs 4 i " F i r ? I; ] tern 2» "Se corid i fern

6, " "

7, " "

10, ""

11, ""

12, ""

0, " "

(5e) A>R2 LIST

CRUN VER 2.04

Fifth

First item Fourth Second i tern Third

digit specifying the file or disk-drive number. A slightly better solution for very large data bases is to use pointers to create a tree structure. However, operations involving trees are very involved, and a discussion of them is outside the scope of this article. Those interested in this subject are encouraged to read the book Algorithms + Data Structures = Programs by Niklaus Wirth, listed in the references.

(5b) 3,4

2. "First i

10, 1 1 , 12,

(5d)

(5f)

Oj

'zzzrzz?

Z Z 7 2 Z Z Z '

6,

1 p i r s t j

tern

5,

'Second

item

2,

'Third

4,

'Fourth

'■? ■,

' F i f t h

10 11

;„„

0,

7,6

4-"First item 5,"Second i tern 2,"Third

'Fifth

10, 1 1, 12, 0, "

Uses of the Linked List

The concepts of linked lists and pointers can also be used to handle data that has a variable amount of additional information associated with it. One particular problem that is unmanageable without linked lists involves a theatre-booking program where you have a movie film and an unknown, highly variable number of dates for which it is scheduled to be used. Because of the uncertainty

The concepts of linked lists and pointers can also be used to handle data that has a variable amount of additional information associated with it.

IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIHIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

involved with the scheduling process, it is usually unacceptable to either limit the number of dates that can be associated with a film or to reserve enough space per film to handle even the most heavily scheduled film.

One solution to this scheduling problem makes use of a linked list. A file containing the essential information for each film can also have, for each record describing a film, a pointer that points to a linked list of date records (each record containing a date and its associated information). Traversing the linked list of dates for any one film is both fast and easy, and each film takes up only as much space for date records as is needed.

The programs and ideas presented here can be converted to work in any programming language that allows some sort of random-access files. In cases where a linked list is applicable, necessity for the additional storage space for the pointers and the slightly increased program complexity are both far outweighed by the ability to directly access related data items with a minimum of searching and sorting.

The difficulty arises in determining whether or not to use linked lists in a particular application. There are, unfortunately, no fixed criteria since the choice of a method will depend on such factors as the computer's disk capabilities, the number of data items, the length of the data items, how often the data will be sorted, and how often the data base will change. You should, however, plan the data base before doing any programming, taking into account the possible methods and the tradeoffs involved. ■

REFERENCES

1. Grogono, Peter, Programming in Pascal, Addison-Wesley, Reading MA, 1973.

2. Wirth, Niklaus, Algorithms + Data Structures = Programs, Prentice-Hall, Englewood Cliffs NJ, 1976.

102 February 1980 © BYTE Publications Inc

INTROL/X-IO.

COMPUTERIZE YOUR HOME.

The lntrol/X-10 peripheral system for your Apple* Computer allows you to remotely control lights and electrical appliances in your home.

YOU'RE ALREADY WIRED.

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lntrol/X-10 comes with complete software to control devices on pre-determined schedules, and features: • Control devices at a specific time. • Select a daily or weekly schedule. • Specify a day of the week, or an exact date for a particular event. • Specify an interval of time for an event. • Rate device wattages for a running account of power consumption during your schedule for energy management. • Used with our Apple Clock™ your schedules may run in "background" while other programs may run at the same time in "foreground."

EVERYTHING YOU NEED.

The Introl Controller board plugs into a peripheral slot of your Apple. With an ultrasonic transducer it transmits control signals to the BSR/X-10 Command Console which may be plugged into any convenient AC outlet near your computer. On command, signals are sent to remote modules located at the devices you wish to control. Up to 16 remote module addresses may be controlled from your Apple.

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BYTE February 1980 103

PUT YOUR IDEAS

(01979 Terak Corporation

IN MOTION FOR $7850.

Invest in a Terak 85 10/a desk top graphics computer for only $7,850, and you'll get the performance of systems costing thousands of dollars more.

The Terak is based on a powerful DEC LSI-1 1 * microcomputer which provides a medium resolution animation capability that until now could only be achieved through larger, more expensive systems.

The Terak operates in either stand-alone or on-line environments, and is fully compatible with DEC hardware.

An independently controlled 4K read/write memory allows the creation of unlimited character sets which permits the display of virtually any language or symbol set that may be required.

There's more. A two-port memory structure means you can display text and animated graphics simultaneously.

The best part is the software. Terak provides comprehensive, easy-to-use operating systems using UCSD PASCAL**, DEC RT-1 1 *, BASIC, APL and FORTRAN IV languages.

If you have a limit on your budget but not your ideas, buy the best price performer in the business. You'll be joining a worldwide community of satisfied users.

For more information, write Terak Corporation, 14405 North Scottsdale Road, Scottsdale, Arizona 85254. Or call (602) 991 -1 580. j

Circle 64 on inquiry card.

These are actual unretouched photos.

*A trademark of Digital Equipment Corp. C*A trademark of the Regents of the University of California.

©I 979 Terak Corporation Animation by Michael Smith, University of Utah. Computer Aided Instruction Group.

A Fast, Multibyte Binary to

Binary-Coded-Decimal

Conversion Routine

Michael R McQuade School of Electrical Engineering

Van Leer Building Georgia Institute of Technology

Atlanta GA 30332

A problem which has confronted users of small computer systems over the years has been the incompatibility of the number representation required by output devices and that used for internal processing. Output devices used by the small systems need to receive binary-codeddecimal (BCD) or ASCII (American Standard Code for Information Interchange) data representations, while the microprocessor is most efficient when handling a straight binary number. Several solutions to the problem exist, and as would be expected, each has its own advantages and disadvantages.

Some users choose to initially store all numbers in their binary-coded-decimal representation and do all subsequent processing in this format. This has the advantage of easy and quick conversion of the numbers into the required output format. At worst, the binary-codeddecimal represented number must be converted to an ASCII format. This requires attaching a fixed 4-bit prefix to each binary-coded-decimal digit.

A disadvantage associated with this approach is that arithmetic operations take longer to perform, since the results must be decimally adjusted after each operation. Also, more memory is required to store the binarycoded-decimal form of the number than is required for its straight binary equivalent. A direct result of this increased memory requirement is the need to perform more

About the Author

Mike McQuade is currently working towards a PhD degree in the Computer Architecture Laboratory at the School of Electrical Engineering at the Georgia Institute of Technology. He has instructed computer courses there, and has taught short microprocessor courses for the Institute of Electrical and Electronics Engineers at both national and regional levels.

memory-access operations to transfer the numbers into and out of the processor. Memory accesses are a very time-consuming operation.

For the users who choose a straight, binary-number representation for internal storage, the advantages of efficient memory utilization and straightforward arithmetic are gained. The question of how to convert the numbers to an acceptable output format for the display device still remains to be answered. This question basically reduces down to converting the binary numbers to binary-codeddecimal form.

Methods of Conversion

There are three basic approaches in wide use. The first approach is to count the binary number down to 0 while incrementing its binary-coded-decimal counterpart up from 0 using modulo-10 counting. Modulo-10 counting performs a decimal-adjust operation after each incremental addition. This method is conceptually easy and requires a minimum of program code if the microprocessor has a decimal-adjust instruction. The counting method can, however, be very time-consuming if large numbers are being converted. For some applications this time penalty would be irrelevant (eg: if the output device is very slow when compared to the processor's cycle time). For a slow output device, any time savings realized by using a faster conversion routine usually has to be wasted in a wait loop.

The second approach is to use some form of table lookup routine. Assuming that the table is extensive enough, the lookup technique performs a very fast conversion. The drawback to this technique is that as the size of the numbers being handled gets larger, either a great deal of memory must be dedicated to the table, or some type of divide-with-remainder scheme must be imple

106 February 1980 © BYTE Publications Inc

WHY DOESN'T

COMPUTER SPECIALIST MOVE TO HUGHES IN SOUTHERN CALIFORNIA?

We need you. But frankly, not everybody you meet along the software trail is good enough to help us stay out in front.

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Concentrate on support software, operating program maintenance, tactical programming, strategic system studies, algorithm development, simulation, or applications software.

Test Software

Help advance the state of test control software and diagnostics to meet hardware tactical and reconnaissance needs.

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Altogether, the growing Hughes population of computer specialists needs to grow even faster by adding systems engineers; systems analysts; applications, diagnostic, and test programmers; and software engineers.

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merited. The division scheme allows the table size to remain small, but it causes the conversion time to increase. As was pointed out earlier, this may not be important, lithe processor being used does not have a decimal-adjust instruction and the numbers encountered are not too large, this second method is very popular.

The third approach in converting from straight binary to binary-coded decimal is to use an algorithm based on the structure of the binary number system. Given the binary number:

b„ b„_, b„_2 . . . b2 bt b0

where each of the bs can represent either a 1 or a 0, and b„ is the most significant bit, it can be expanded as:

b„ X 2" + b,,., X 2-' +

+ b, X 21 + b0 X 2° (Form I).

Form I is not conducive to an iterative-type binary to binary-coded decimal conversion routine, but can be rewritten as:

(. . .((b„ X 2) + b,,.,) X 2 +

+ b,) X 2 + b„ (Form II)

Form II contains only the decimal numbers 0, 1, and 2, which have the same representations in either straight binary or binary-coded decimal. Straight binary and binary-coded-decimal representations of a number differ only for numbers greater than 9. While straight binary adheres strictly to position weighting in powers of 2, binary-coded decimal treats each decimal digit of the number independently and represents it as a 4-bit straight binary number.

If Form II is implemented using binary-coded-decimal arithmetic (performing a decimal adjust after each addition), the final result will be in binary-coded-decimal representation. Form II lends itself to an iterative-type implementation which allows it to be coded to easily accommodate any size number.

Carry

0 0

1 1

Auxiliary Carry

0 1 0

1

Correction Factor

10011010 10100000 11111010 00000000

Table 1: Correction factors in binary for the binary to binarycoded-decimal (BCD) conversion algorithm.

Much has been said about performing a decimal-adjust operation when operating on numbers in the binarycoded-decimal format. When two binary-coded-decimal numbers are added by the processor's straight binaryadding accumulator, the result is not in binary-codeddecimal form. It is necessary to perform one more operation after each addition to correct for the fact that the processor's arithmetic logic is designed to add straight binary numbers. This extra operation is the decimal adjust. Many of the microprocessors on the market today have the decimal-adjust operation contained in their instruction sets.

If the processor being used does not contain a decimaladjust instruction, it is still possible to perform a decimaladjust operation. What must be done is to allow for the fact that a binary-coded-decimal number uses only ten of the sixteen possible 4-bit combinations for each digit. If two binary-coded-decimal numbers are added together, and the least significant 4 bits of the result have a value greater than 9, then 6 must be added to the result. It is necessary to add 6 to skip over the six unallowed BCD bit combinations. The next 4 bits of the result are then tested, and 6 is added to them if necessary. This is repeated across the entire result.

A Better Method

The above method works in theory but is rather awkward to program. Let us examine a method based on the above theory which lends itself to straightforward programming. The method will be for 8-bit processors,

f^ S-100 USERS: GIVE YOUR COMPUTER THE GIFT OF SIGHT!

The DS-80 Digisector® is a random access video digitizer. It works in conjunction with a TV camera (either interlaced or non-interlaced video) and any S-100 computer conforming to the IEEE standards. Use it for:

• Precision Security Systems

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• Computer Portraiture

• Fast To Slow Scan Conversion

• Robotics

• Reading UPC Codes, schematics, paper tape, musical scores

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108 February 1980 ® BYTE Publications Inc

Circle 66 on inquiry card.

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BYTE February 1980

Listing 1: The multibyte binary to binary-coded-decimal (BCD) conversion algorithm coded as a subroutine for the 8080 microprocessor.

THE SUBROUTIICS ALWAYS SAVE TIC CONTENTS OF REGISTERS A D E H L AND THE STATUS FLflGS. IF THE CONTENTS OF REGISTERS B C NEED TO BE SRVED THE CALLING ROUTINE MUST EXPLICITLY DO IT.

,***********

»8INARY TO BCD CONVERSION SUBROUTINE'

THE SUBROUTINE CONVERTS ft MULTI-BYTE BINARY NUMBER TO ITS EQUIVALENT MULTI-BYTE BINARY CODED DECIMAL (BCD) REPRESENTATION THE BYTES OF BOTH NUMBERS ARE STORED IN MEMORY IN ASCENDING ORDER WITH THE LEOST SIGNIFICflNT BYTE IN THE LOW DC OF THE MEMORY STftCK. THE REQUIRED PARAMETERS NEEDED TO BE PftSSED RRE:

H L GETS ADDRESS OF LOU ORDER BYTE OF BINARY NUMBER D GTS NUMBER OF BYTES IN BINARY NUMBER E GETS NUMBER OF BYTES IN BCD RESULT AREA

THE SUBROUTINE ASSUMES THAT THE BINARY HUMBER HILL FIT IK THE SUPPLIED NUMBER OF BCD BYTES. THE ROUTINE UILL FILL IN THE BCD BYTES WITH LEADING ZEROS IF NECESSARY.

eeee F5

BNBCD:

PUSH

PSH

SAVE STATUS

eeei«

NOV

C,E

COPY 1 BCD BYTES TO C

8882 E5

PUSH

H

SAVE ADDR OF BINARY # ON STACK

9883 216488

LXI

H.BCDNL

LOAD HL WITH ADDR OF BCD t

vOPQ MlffO

LflB16:

HVI

0,8

ZERO OUT MEMORY LOCATION

8888 23

I NX

H

INCREMENT HL

8889 BD

OCR

C

DECREMENT C

MR C286B8

JNZ

LRB16

IF C=8 BRANCH FROM LOOP

888D 7R

MOV

fl,D

PUT 1 OF BINARY BYTES IN A

986E 87

ROC

A

B88F87

ADC

A

MULTIPLY BY 8 TO GET 1 OF BITS

8818 87

ADD

A

8811 47

MOV

B,A

STORE 1 OF BITS IN B

8812 AF

XRfl

A

SET CARRY TO ZERO

8813 4A

MLOOP

MOV

CD

PUT 1 OF BINARY BYTES IN C

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8814 El

POP

H

RESTORE ADDR OF BINARY 1 TO HL

8815 3B

OCX

SP

8816 3B

DCX

SP

LEAVE HL ON STftCK

8817 7E

RLOOP:

MOV

A,M

PUT BINARY BYTE IN A

8818 8F

ADC

ft

SHIFT BYTE LEFT t FILL KITH CflRRY

8819 77

NOV

H,fl

REPLflCEBYTE

881ft 8D

DCR

C

DECREMENT C

991B CR22B8

JZ

LftB17

BRflHCH FROM LOOP IF LftST BYTE

881E 23

I NX

H

INCREMENT HL

881F C31788

JHP

RLOOP

JUMP TO STRRT OF ROTATE LOOP

8822 El

LBB17:

POP

H

RESTORE HL POINTER TO LOW ORDER BINARY BYTE

8823 38

DCX

SP

8824 36

DCX

SP

LERVEHL ON STftCK

8825D22988

JNC

LAB18

SKIP FILL HITH ONE IF NO CfiRRY

8828 34

INR

M

FILL HITH ONE

8829 4B

LBB18.

MOV

C,E

PUT 1 OF BCD BYTE IN C

882A 216488

LXI

H.BCDNL

LOAD HL WITH RDDR OF BCD

882D 3E88

LftB28:

MVI

ft, 8

ZERO OUT R

882F BE

ADC

M

ADD BCD BYTE TO A WITH CftRRY

8838 27

DBA

CONVERT RESULT TO BCD

8831 77

MOV

M,A

SAVE NEW BCD BYTE

8832 D23R88

JNC

LftB19

SKIP REST IF NO CARRY

8835 23

I NX

H

POINT TO NEXT BCD BYTE

8836 8D

DCR

C

DECREMENT C

8837 C22D88

JNZ

LflB28

IF C=8 LEAVE LOOP

883ft 46

LHB19:

MOV

C,E

PUT 1 OF BCD BYTE IN C

883B 85

DCR

B

DECREMENT BIT COUNT

883C Cfl4E88

JZ

LAB48

EXIT MfilN LOOP IF COUNT = 8

883F 216488

LXI

HBCDNL

LOAD HL WITH RDDR OF BCD CflRRY=« ENTERING NEXT LOOP WHICH MULTIPLIES BCD 1 BY TWO

8842 7E

LflB21:

MOV

ft,M

, PUT BCD BYTE IN ft

8843 8E

ADC

M

; ADD BCD BYTE TO ITSELF WITH CflRRY

8844 27

DftA

I CONVERT RESULT TO BCD

8845 77

MOV

N,A

iSAVE NEW BCD BYTE

8846 23

I NX

H

; POINT TO NEXT BCD BYTE

8847 8D

DCR

C

i DECREMENT C

8848 C24288

JNZ

LAB21

i IF C=8 LEftVE LOOP

884B C31388

JMP

MLOOP

;D0 FOR ALL BITS OF BINARY 1

884E El

LAB48:

POP

H

iRESTORE HL

884F Fl

POP

PSW

; RESTORE STfiTUS

8858 C9

RET

1 RETURN

since they are the most popular. First it is necessary to keep track not only of the carry out of the eighth bit position, but also the carry from the fourth to fifth bit position. This second carry will be referred to as the auxiliary carry.

(1) Add the binary number 01100110 to the first number.

(2) Add the second number to the result generated in step 1. Keep track of both the carry and auxiliary carry from this addition. The carry generated here is the true carry to the next higher digit.

(3) Based on the carry and auxiliary carry generated in step 2, add one of the correction factors shown in table 1 to the result of step 2.

The result has now been decimally adjusted.

The program shown in listing 1 and the flowchart shown in figure 1 provide an implementation of Form II using binary-coded-decimal arithmetic for the Intel 8080 microprocessor. It uses the decimal-adjust (DAA) instruction in the 8080's instruction set. A simple program shown in listing 2 converts data from binary-coded decimal to ASCII representation. The conversion from binary-coded-decimal to ASCII entails taking each of the two 4-bit, binary-coded-decimal digits, putting them in a byte, and appending the binary prefix 0011. Both programs are coded as subroutines, since these forms are usually more convenient to include in larger programs.

The binary-to-binary-coded-decimal subroutine of

110 February 1980 © BYTE Publications lnc

Circle 67 on inquiry card.

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In an era when computers are an integral part of business and entertainment, and computer software is more and more sophisticated, Aardvark is yet another breed in advanced computer software. Aardvark's Micro Tax series is a true user-oriented Federal I ncome Tax package. Specifically developed by qualified tax professionals for use on personal home computers, this low-cost, time-saving Aardvark Micro Tax package accurately and efficiently computes your federal income tax liability. Aardvark will display and fill in facsimile Form 1040 and related schedules and, if connected to a Centronics printer, will print out these facsimile forms auto

matically. Each program is designed to use the appropriate tax table or rate schedule. The more advanced Micro Tax II and III also calculate Income Averaging, Maximum Tax on Earned Income, Minimum Tax and Alternative Minimum Tax. The Aardvark package is compatible with Apple II and TRS-80 users and includes an indexed instruction manual and input forms for easy input of tax data. To see how Aardvark can be tax-deductible, check the instructions in the binder of the manual. You can also use the binder to store pertinent 1979 tax records. Cure your headaches this tax season, order today...and put the BYTE on the IRS with Aardvark!

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PUZZLE YOUR COMPUTER

Your computer can make puzzles for you to solve with these new cassettes from Program Design.

i ■■■■■■■■■

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ftrfwc

Minicrossword

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Two Codeword puzzles on the same cassette use the same words in a word-guess game. The 4 programs are a vocabulary and spelling development system for adults and high schoolers. TRS-80 Level II (16K), or APPLE II Applesoft $14.95

T G I I T

H fit

I L

A M

n * u „.

Y B N X M N U L Z T T S E S Q

B D J

D D R

K G X 0 0 D

1 « J R 0 u N M U Y Y H x L I S A H K Z R G If U

A H X G K

H

A

H C

A V

OBAN

L S A U D

I

A

R A

B I

A G B M

A U IS S V

F

P

N R

M L

B M P U

U L E X Q

F

Z

A d

P Y

H B N J

W I K Q F

0

Z

R A

E U

M I J E

J D M T R

I

N

I D

A D

E Z R I

H M J M L

c

0

0 T

Q H

K M L U

V N K P J

X

I

U K

J D

R N R Y

5 WORDS-GUESS? ?_

Astro Word Search Series

The computer makes hundreds of the popular word-search type puzzles from words in its memory. Words are hidden across, down, diagonally - forward and backward in a maze of letters. The computer flashes the words you find and scores you on how well you do. Teaches vocabulary and facts in a fun way.

Astro Word Search: Geography

(geographical place names)

Junior High to adult- Level II, 16K $14.95

Astro Word Search: Spanish

(Spanish vocabulary words)

High School to adult- Level II, 16K $14.95

Look for these titles at your participating Computerlands and other fine computer stores.

Or order direct from Program Design,

11 Idar Court, Greenwich, CT 06830 (203) 661-8799.

Master Charge, Visa. Add 5% shipping.

Circle 69 on inquiry card.

f BNBCD J

INITIALIZE BCD NUMBER TO ZERO

INITIALIZE BIT COUNTER 8 X D

ROTATE BINARY NUMBER LEFT WITH COPY OF MOST SIGNIFICANT BIT IN CARRY

GET LEAST SIGNIFICANT BYTE OF BCD NUMBER

1

ADD CARRY TO BYTE USING BCD ARITHMETIC

GET NEXT BINARY-CODED DECIMAL BYTE

YES

YES

GET LEAST SIGNIFICANT BYTE OF BCD NUMBER

ADD BYTE TO ITSELF WITH CARRY USING BCD ARITHMETIC

DECREMENT BIT COUNTER

GET NEXT BCD BYTE

( RETURN )

Figure 1: Flowchart of the algorithm for the binary to binarycoded-decimal (BCD) conversion subroutine.

listing 1 requires contiguous memory locations to hold the binary-coded-decimal result. The address of the memory location for the low-order byte of the binarycoded-decimal number has been labeled BCDNL (binarycoded-decimal number location) in the subroutine. The

112 February 1980 @ BYTE Publications Inc

HI THERE!

It has come to our attention that many of our customers are not aware of the wide variety of products we have available. Following is a list of all our current major products and prices. Watch BYTE for new items,

Part No.

MEM-3 2K-ASM MEM-16K-ASM

CI-ASM

CI-KIT

FDI-ASM

FDI-KIT

DD-ASM

DD-KIT

VDS-II

VDS-IID

PS270

SIM120

SHU800

CP272

CP206

CP206

TBAS-CAS TBAS-DSK

TBAS-LST

TBAS-SRC

PTSW+LST

EMPL-CAS

EMPL-DSK

CPM-2.0

CPM-1.4

CPM-1.4-M

CPM-MS

BASE-MAN

BASE-LST

PBLC-DMN-1

PBLC-DMN-2

CBAS-DSK

CBAS-MAN

SPLR

FAST

TELE-COM

POLYVUE

PASCAL/MT

out

Description

Tarbell 32k Static Memory for S-100 bus

Tarbell 16k Static Memory for S-100 bus

(Memories only come assembled & checked out)

Cassette Interface Assembled & Checked out

Cassette Interface Kit

Floppy Disk Interface Assembled & Checked

Floppy Disk Interface Kit

Double Density Floppy Disk Interface A&T

Double Density Floppy Disk Interface Kit

Vertical Disk Subsystem

Double Density Disk Subsystem

PerSci Model 270 Dual Floppy Disk Drive

Siemens Model 120-8 Single Floppy Disk Drive

Shugart 800/801 Floppy Disk Drive

Power Supply for PerSci 270 Dual Drive

Power Supply for PerSci 299

Power Supply for Two Siemens or Shugart

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725.00 440.00

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Tarbell Cassette BASIC on cassette incl manual Tarbell Disk BASIC on CP/M disk incl manual Note: the following two items can only be ordered with Tarbell Disk or Cassette BASIC: Tarbell BASIC source listing on paper Tarbell BASIC source on 2 CP/M disks Proc Tech Assembler/Editor with listing EMPL micro APL on cassette & instructions EMPL micro APL on CP/M disk & instructions CP/M 2.0 Operating system incl documentation CP/M 1.4 Operating system incl BASIC-E on disk CP/M 1.4 on soft-sectored MINI-FLOPPY disk CP/M 1.4 Operating system manual set (of six) BASIC-E Compiler Manual (works with CP/M) BASIC-E Source Listing (in PL/M) Public Domain Disk #1 - includes DISKTEST, BASIC-E, CBIOS, FORMAT, TAPELIB, etc on disk Public Domain Disk #2 - includes Double Density FORMAT, DISKTEST, Auto-BIOS for 1.4 & 2.0; FORTH 15 CBASIC-2 disk 85

CBASIC-2 manual 15

KLH Systems Spooler for CP/M on disk 70

FAST! Screen-oriented Editor/Assembler for CP/M 100 Software to operate D.C. Hayes Modem Remote 195 Screen-Oriented CP/M Editor 135

Meta-Tech Pascal Compiler for CP/M 99

48 48

25 25 15 15 20 150 70 70 25 5 15

.00 .00

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10.00

.00 .00 .00 .00 .00 .00 .00 .95

Prices are subject to change without notice.

California residents please add 6% sales tax.

For guick delivery, see your local Tarbell dealer.

Circle 70 on inquiry card.

950 Dovlen Place, Suite B Carson, California 90746

(213) 538-4251 (213) 538-2254

Listing 2: A subroutine to convert a single-byte, 2-digit, binarycoded-decimal number to two single-byte ASCII characters, coded for the 8080 microprocessor.

TO RSCII SUBROUTINE*

*******

;THE SUBROUTINE TAKES A TMO DIGIT BCD NUnKR IN MEHORV POINTED TO BY

iHL AM) CONVERTS IT TO ASCII. THE MOST SIGNIFICANT DIGIT IS PUT

I IN REGISTER B WILE THE LEflST SIGNIFICANT DIGIT IS PUT IN REGISTER C.

6851 F5 ASCII: PUSH

PSH

SAVE STATUS

8852 3E8F

M

H99891111B

PUT LEAST SIGNIFICANT DIGIT MASK IN A

9854 AC

AHA

n

MASK OFF LEAST SIGNIFICANT DIGIT

9855 F638

ORI

eeiieeeee

CONVERT TO ASCII

9857 4F

NOV

C,A

PUT IN REG C

9858 3EF8

11VI

fbuueeeee

PUT MOST SIGNIFICANT DIGIT MASK IN A

985A At

ANA

M

MASK OFF HOST SIGNIFICANT DIGIT

985B 9F

RRC

985C 9F

RRC

9850 BF

RRC

985E OF

RRC

ROTATE RIGHT FOUR PLACES

985F FR8

ORI

981188996

CONVERT TO ASCII

8861 47

HOV

B,R

PUT IN REG B

8962 Fl

POP

PSH

RESTORE STATUS

8863 C9

RET

RETURN

8964 BCDNL: DS

31

START OF BCD NUMBER

0800

END

number is ordered upwards in memory. Register E must contain the number of bytes in the binary-coded-decimal number when the subroutine is called. If more bytes are specified than are needed, the extra will be filled with leading zeros.

The other parameters which must be passed to the subroutine are the number of bytes in the binary number and the address of the low-order byte of the binary

number. The number of bytes in the binary number is to be in register D, while the address of the low-order byte is in register pair HL. The binary number is assumed to be stored in memory using the same convention as the binary-coded-decimal number. The more significant bytes are found at increasing memory addresses.

By having register pair HL point to the binary number, the routine can be used to convert all binary numbers required by the user's program without moving them to a specific location. All results are put in the same location, since this is temporary storage needed only until the number is sent to the display device.

The binary to binary-coded-decimal conversion subroutine provided can handle binary numbers of any length up to and including 31 bytes. This corresponds to a decimal number in excess of 4.5 X 1074 with a full 75 significant digits. This should be adequate to handle any physical quantity encountered. To establish a reference, it is only about 1.5 X 1021 angstroms from the earth to the sun. (An angstrom is one ten-billionth of a meter, that is 1/109, and is normally used to measure the wavelength of light.)

The routines provided have been tested using a highspeed line printer as an output device. The routines were fast enough to allow the line printer not to wait when being sent a stream of 6-digit numbers. While the routines have been tested and were fast enough for the desired applications, an extensive effort was not made to eliminate every unneeded processor cycle. The object code provided in listings 1 and 2 will also execute on an Intel 8085 or a Zilog Z80 microprocessor. ■

§^

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WHEN ORDERING PLEASE ADVISE PUBLICATION SOURCE

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REMODEL + PROLOAD Specify 16, 32, or 4fiK Memory $34.95

RENUMBER any portion or all of BASIC program. Line references

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MOVE any portion of a BASIC program from one location to

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DELETE lines or ranges of lines while using the utility.

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300-500 from your tape to existing program at line 1000 with

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SAVE combined/merged programs, or any portion to tape with

VERIFY.

COPSYS Copy Systems Tapes (Editor/Assembler Format) $14.95 J \

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18 Machine language routines using 'USR' calls. Includes RACET sorts, array handling, and fast lines and scrolls.

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MOD II SUPPORT

RACET is supporting the MOD II!!

Call or write for current information! We have a MOD II Superzap

and other assembly language tools!

Ask your dealer if he carries our products!

DEALERS! We will work with you directly or through our

distributors.

114 February 1980 © BYTE Publications lnc

Circle 71 on inquiry card.

"Superbrain is a registered trademark of Intertec Data Systems.

System Specifications

Microprocessors

Word Size Execution Time Machine Instructions Interrupt Mode Floppy Disk

Storage Capacity

Data Transfer Rate Average Access Time Media

Disk Rolation Interna] Memory Dynamic RAM Static RAM

ROM Siorage

CRT

Display Size

Display Format

Character Font

Line Drawing Character:

Display Presentation

Bandwidth

Cursor Communications

Screen Data Transfer

Auxiliary Interface

Parallel Interface

S-100 Bus

Transparent Mode

Parity

Transmission Mode

Addressable Cursor System Utilities

Disk Operating System

DOS Software Optional Software

FORTRAN

COBOL

BASIC

Application Packages

Keyboard

Alphanumeric Character Special Features Numeric Pad Special Functions Keys Cursor Control Internal Construction Cabinetry Component Layout

Twin Z80A's with 4MH2 Clock Frequency One Z80A (the host processor) perlorms all

processor and screen related functions The second Z80A is "down-loaded" by (he host to

execute disk I/O When not processing disk data, the second Z80 may be programmed by

the host for other processor related functions

8 bits

1 0 microseconds register to register

158

All interrupts are vectored

320K tola! bytes formatted on two double density drives Optional external 10-300

megabyte hard disk storage is available using optional S-1 00 bus adaptor

250K bits/second

250 milliseconds 35 milliseconds track-to-track

5■■'• inch minidisk

300 RPM

64K bytes dynamic RAM

256 bytes of static RAM is provided in addition to the mam processor RAM This memory

is used for program and/or data storage- for the auxiliary processor

1 K byles standard Allows ROM "bootstiapping" of system at power-on ROM storage is

2708 compatible and may be reptogrammed by the user for custom applications

1 2-mch. dynamically focused P4 phosphor 25 lines x 80 chaiacters per line 8x8 character matrix on a 8 x 12 character field i Eleven special graphics symbols used loi form generation Light characters on a dark background Reversible through keyboard.'piogram selection 20 MHZ Reversed image (block cursor)

Memory-mapped at 38 kilobaud Serial transmission ol data at rales up to 9600 bps

Universal RS 232 asynchronous Syncnronous interlace optional

Radio Shack TRS-80 compatible

Printed circuit edge connector provided for connection of optional S-100 bus adaptor

Enables display of all incoming and outgoing control codes

Choice of even, odd. marking, or spacing

Hall oi Full Duplex One or two slop bils

Direct positioning by either discrete oi absolute addressing

CP'M

An 8080 disk assembler, debugge:

text editor and file handling utilities

Weight

Physical Dimensions

Environment

Power Requirements

ANSI standard Relocatable, random ar.d sequential disk access

ANSI standard Relocatable, sequential relative and indexed disk access

Sequential and random disk access Full string manipulation, interpreter

Extensive software development tools are available including software for the following

applications Payroll. Accounts Receivable. Accounts Payable. Inventory Control. General

Ledger and Word Processing

Generates all I 28 upper and lower case ASCII characters

N-Key Rollover Automatic repeal (at 15 CPS), Keyboard lock/unlock

0-9. decimal point, comma, minus and four user programmable function keys

Up to 64 user-defined two-key function sequences

Up. down, forward, backward, and home

Structural foam

Two board modular design All processor related functions and hardware are on a single printed circuit board All video and power related circuits on a separate single board These two boards are interconnected via a single 22-pin ribbon cable CRT and two circuit boards mounted to base CRT in a rigid steel frame Disk Drive assembly mounted into upper cover lor ease of servicing

Approximately 45 pounds

14 W (H> x 21 ¥* (W) x 23 /■■ (D)

Operating 0' to 50' C Storage 0 to 85 C. 10to95%rel humidity - non condensing

I 1 5 VAC. 60 HZ. I AMP (optional 230VAC SOHZ model available)

' Specilicitmns suhii't'l '<• Change wilhnul noliti

SUPRBRAIIST

The Honor Graduate

OEM's... End Users... Computer Dealers.

I

SuperBrain users get exceptional performance for just a fraction of what they'd expect to pay. Standard system features include: two double density minifloppies with 320K bytes of disk storage, 64K of RAM memory to handle even the most sophisticated programs, a CP/M Disk Operating System with a high powered text editor, assembler, debugger and a disk formator. And, with SuperBrain's S-100 bus adaptor, you can add all the programming power you will ever need. . . even a 10 megabyte disk!

SuperBrain's CP/M operating system boasts an overwhelming amount of available software in BASIC, FORTRAN, COBOL, and APL. Whatever your application . . . General Ledger, Accounts Receivable, Payroll, Inventory or Word Processing . . . SuperBrain is tops in its class. But best of all, SuperBrain tackles your toughest jobs for less than onethird the cost of other similar systems.

You'll appreciate the careful attention given to every engineering detail. Standard SuperBrain features include: a full ASCII keyboard with numeric pad and user-programmable function keys. A non-glare, dynamically focused, 1 2-inch CRT for sharp images everywhere on the screen. Twin Z80 microprocessors to insure efficient data transfer to auxiliary peripheral devices. A universal RS-232 communications port for serial data transmission. And, a single board design to make servicing a snap!

Performance and packaging have never been better matched. Your operators will appreciate SuperBrain's good looks. You'll appreciate SuperBrain's outstanding value. Twin Z80A processors, dual double density disk drives, and a high resolution CRT terminal. All in a single, smart looking, selfcontained desktop unit. And, all for a price that's substantially less than the competition!

Make no mistake about it. The freshman students in the small systems business can't begin to compete with this year's honor graduate. The SuperBrain. The only system at the top of its class in price and performance

DEALER/OEM QUANTITIES AND SPECIAL PRICING AVAILABLE VIA MICROAMERICA DISTRIBUTING

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MICROAMERICA DISTRIBUTING

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21 Putnam Street

Needham, MA .-%,*„,

02194 (617)449-4310

Circle 72 on inquiry card.

BYTE February 1980 115

A Quad Terminal Interface

Stephen A Alpert 11 Ridgewood Dr Auburn MA 01501

WORD ADDRESS

5 8

SITS 7

6

0

Every now and then, a micro or minicomputer owner may be fortunate enough to have more than one terminal and probably a modem or two. Unfortunately, there never seem to be enough interfaces to the computer system to connect all these

KEYBOARD STATUS

INTERRUPT ENABLE DONE FLAG

KEYBOARD DATA DATA IN LOW BYTE

PRINTER STATUS

INTERRUPT ENABLE DONE FLAG

PRINTER DATA DATA IN LOW BYTE

5 8

7 0

I

5 8

7

0

Figure I: Addresses required for a single terminal are the low bytes of four consecutive words.

• Each terminal requires four words of 16 bits each. The bits in a word are numbered 0 to 1 5 from right to left. Hence, the low byte in a word contains bits 7 thru 0 and the high byte contains bits 1 5 thru 8.

• The first word contains only two bits of interest. Bit 7, the most significant bit in the low byte, is the keyboard done flag. It is set when a byte is received as input. It is cleared by a bus initialization (BUS IN IT) or a processor read of the data. Bit 6 is an interrupt enable bit for the keyboard. When set, an incoming character will cause an automatic vectored interrupt through the processor.

• The low byte of the second word contains the keyboard data.

• The third word is arranged like the first word but is used for the printer side of the terminal. Bit 7 is set by a bus initialization signal (BUS INIT) or when the interface can accept another byte from the computer and is cleared when a byte is sent to the terminal.

• The low byte of the fourth word is the data buffer for the printer.

Table I: Device addressing organization for interface configuration shown in figure 7.

devices into the system at the same time. This article chronicles my local solution to the problem.

Through luck and a lot of hard work, my computer system consists of a Digital Equipment Corporation PDP-11/10 processor, a video monitor, a teleprinter, a modem and only one terminal interface. Conveniently, the video monitor, which serves as the main console, is driven directly off the processor. This still meant that there was a deficiency of one terminal interface.

After reviewing the schematic for the interface that I had, I started a design to essentially duplicate that board. A friend jokingly suggested that a design should be generated to drive several terminals at once. Taking that thought seriously, my course of action had been charted.

The creation of this quad terminal interface involves ideas applicable to almost any sort of processor that uses memory addressed IO. That is, the processor contains no special IO instructions, but instead addresses specific memory addresses to communicate with the status registers and buffers of the peripheral devices. This tradeoff means that the devices look like memory and the processor can therefore be equipped with additional instructions at the loss of memory space.

In the case of the PDP-11 series, the processor has a 16 bit data bus and an 18 bit address bus. In this byte addressable machine, the maximum user address space is 32 K words. However, the processor automatically takes all addresses in the range of 160000 to 177777 octal and maps them to 760000 to 777777 octal. (Digital Equipment Corporation uses octal notation in all software.) That means the user memory space is limited to 28 K words with the addresses generated by the processor for 124K to 128K specified for the IO page.

116 February 1980 © BYTE Publications Inc

About the Author

Stephen AI pert is an associate professor of computer science at Worcester MA Polytechnic Institute. He was the first vice chairman of the ACM's special interest group for minicomputers (SIGMINI) and is a software consultant to Digital Equipment Corporation through Hias Inc. He has owned a minicomputer since 1973.

Stephen wishes to thank R Hully, the president of Hias Inc, for the use of personnel during construction of this equipment.

The organization for the device addressing used on the interface in figure 1 is summarized in table 1. This structure is imposed primarily by the requirement to maintain compatibility with the interfaces supported by the existing software. Essentially, the interface should look to the software exactly like four separate terminal interfaces. A microprocessor could easily utilize this memory layout in consecutive bytes in page zero.

Without the interrupt enable (IE) bit set, the keyboard status register must be constantly checked by the program for the presence of a byte of data. This overhead is wasteful and serves no utility except in the case where the processor has nothing else to do. The processor can acknowledge an interrupt by automatically jumping to a special location in page zero whenever an interrupt occurs. A routine must either poll the individual devices or, via some kind of acknowledge instruction, get information off the bus pertaining to an address of the desired routine or identification of the device requesting the interrupt. This software overhead in a minicomputer makes for very inefficient performance. Also, what happens when more than one device requests service simultaneously? Interrupt masking of some sort is needed. What about a possible priority based on the requests?

The PDP-11 processor eliminates these problems by utilizing hardware priority arbitration and vectored interrupt logic. The processor allows four levels of interrupt requests and a nonprocessor request mode for direct memory access (DMA). Once the processor decides to allow an interrupt request, it issues a BUS GRANT on one of the four lines corresponding to the different interrupt levels. This grant line is fed in sequence from one device to the next. Each device that does not want the grant is responsible for passing it along to the next device as shown in figure 2. In this way, the device closest to the processor always

gets the grant first in the case of simultaneous requests on the same line. After the grant has been received by the requesting device, that device is responsible for asserting an interrupt service request and simultaneously asserting a 9 bit address on the data lines of the processor's single bus. The processor will accept this address not as an address of a routine, but rather as a pointer to a pair of words. The first word contains the address of the interrupt service routine and the second word contains a new processor status word. The old program counter and processor status word are saved on the processor's stack. This complete sequencing requires approximately 7 /is in the PDP 11/10.

From the previous discussion, it is apparent that the interface must properly decode 16 distinct word addresses, four for each terminal, along with the proper read or write lines. Furthermore, to eliminate redundant hardware, and save space on an interface board, the logic must do some of its own decoding and encoding of addresses and data. The program counter and Text continued on page 120

PROCESSOR

DEVICE #1

DEVICE #2

-<. I BUS REQUEST I -<^J BUS REQUEST 0

I > BUS GRANT I BUS GRANT 0

n°

DEVICE #3

Figure 2: Typical bus request and grant arrangement with two levels. Requests are asserted on a particular request line of the processor. Grants are generated from the processor and daisy chained through the devices associated with that level.

February 1980 © BYTE Publications Inc 117

Lgan

There's only one small computer that can give you your heart's desire:

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You don't mean to be greedy. But you're part of the new "Gimme" generation with big plans for the future. You expect your computer to be flexible enough to keep up. Only one system on the market today can do that: the Exidv Sorcerer.

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Our ROM PACs are special plug-in software cartridges that turn your Sorcerer into all sorts of different computer centers instantly. Just pop a STANDARD BASIC PAC™ into Sorcerer, and you're ready to program any application in high-level BASIC. Or plug in a DEVELOPMENT PAC™ and you have a low-cost Z80 software development system costing less than $1700.

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s-100 Expansion & 128 User-Defined Symbols

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WORDPRO

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Hardware Price*

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25-pin serial interface. Serial interface (48K model) operates one or two cassette recorders. Graphic resolution of 240x512, 30 ines of 64 characters, 8x8-dot matrix. Character generator contains full ASCII set (upper & lower case), plus standard graphic symbols. User may define up to 128 characters. Keyboard is 63-key data processing type, plus 16-key numeric pad.

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□ Display Disk: single unit package $2995 containing two quad density dual floppy disks (630K bytes) with controller and 12-inch industrial grade CRT (P31 phosphor). Includes CP/M™and Microsoft disk-extended BASIC.

D Floppy Disk Subsystems.- single $1150

dual-density floppy disk (120K bytes) and controller in one package. IncludesCP/M™ and Microsoft disk-extended BASIC.

□ S-100 Expansion Unit: self- $ 419 contained 10-amp power supply and motherboard with 6 card slots. Daisy chain units for more slots.

Software

□ Development PAC™ $

□ Word Processing PAC™ $

□ EPROM PAC™ $

□ Microsoft Disk-Extended BASIC $

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' U S domestic prices only Subject lo change without notice CP/M is a Registered Trademark of Digilat Research

99 199

49 300 145

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Data Systems Division 390 Java Drive Sunnyvale. CA 94086 (408) 734-9410

Circle 73 on inquiry card.

NUMBER

TYPE

+ 5V

GND

ICI

74LS266

1 4

7

IC2

74LS266

14

7

IC3

7410

14

7

IC4

7442

16

8

IC5

7442

16

8

IC6

74148

16

8

IC7

7442

16

8

IC8

74123

16

8

IC9

7438

14

7

ICIO

7438

14

7

ICI 1

NE556

14

7

ICI2

7493

5

10

BUS TO PRINT BUFFER BUS TO PRINT STATUS BUS TO KEYBOARD STATUS PRINT STATUS TO BUS KEYBOARD BUFFER TO BUS KEYBOARD STATUS TO BUS

Figure 3: Address decoding circuitry.

Text continued from page 117: processor status word for the service routines are placed in low memory of addresses less than octal 776 by the software and not by the hardware.

The memory words necessary for this interface will consist of D type flip flops for the status registers since only two bits are needed per word. The input and output data buffers may be hooked directly to the UARTs. UART is, of course, an abbreviation for the Universal Asynchronous Receiver Transmitter, a device which converts parallel bytes of data into a serial stream of bits in an industry standard, time ordered format. The specific UART used in this design is the General Instruments part numbered AY-5-1 01 3.

The address decoding circuitry is shown in figure 3. All signals are conditioned by bus receivers and are not considered valid until the processor asserts a master synchronization signal (MSYN). The 74LS266 is a 4 bit digital comparator with open collector outputs that are "wire ORed" to detect the

proper setting of six address lines. The address may be selected by the adjustment of the switches. A pair of 7485 magnitude comparators could have been used in series since they only require a 48 ns delay to compare six bits. The MSYN signal is not asserted until at least 75 ns after the address lines have been activated. Notice the use of two 7442s, binary coded decimal decoders. Since all addresses are in consecutive words, given a base address, say X, the first terminal will use addresses X to X+6, the second terminal will use addresses X+10 to X+16, and so on. IC4 will only assert one of its lower four output lines if the address is in the range for that terminal. IC5 is used with the low address bits and the read or write control lines to indicate which action must be done for the specified terminal. Note that the keyboard data buffer is a "read only" memory and the printer data buffer is a "write only" memory.

The UARTs used in this interface require a transistor-transistor logic load

120 February 1980 © BYTE Publications lnc

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BUS DATA fj>BUS TO STATUS O

INT-BACK-L

B Q

INTERRUPT BACK

INTERRUPT "O REQUEST INT-REQ-L LINE

NUMBER

TYPE

+ 5V

GND

ICI IC2

7474 7411

14

14

7 7

Figure 4: The interrupt logic for each UART consists of a pair of these circuits: one for transmit and one for receive. For the complete interface, eight copies of this circuit are required, so the sections of the 7474 circuits are referenced in text by A and B.

(1.6 mA) for the data inputs and have three state data outputs capable of driving one transistor-transistor logic load. Since the data ports had to be buffered to correctly interface to the processor bus, all input data ports could be wired in parallel and the same for the output data ports. All individual signals to and from each UART must be conditioned via AND or NAND gates to insure communication with the correct terminal unit.

The most difficult task remained: designing the necessary interrupt logic. It was desirable to make the priority of all keyboards higher than any of the printers. This way, no characters would be lost. The inclusion of four terminal drivers on a single board forces a significant increase in the complexity of the interrupt logic.

The interrupt logic consists of two related sections. The first section required properly generating an interrupt from either the input or output side of the UART. Figure 4 shows the circuit for one side of a UART. This circuit appears eight times in the completed board. The interrupt enable bit must have been set through a 7474 flip flop section labeled A in figure 4. Initially, the B section of the 7474 is off so the interrupt request line (INT REQ L) is high and not asserted. Likewise, the interrupt back line (INT BACK L) is high and not asserted. When a character is received (in the case of the receiver side of the UART), UART DONE causes a low to high level transition on the clock input_of the B section of the flip flop. Since Q was high,

D is high and Q is then_asserted, making the interrupt request line (Q) active. This signal then serves as input to the interrupt arbitration logic. The interrupt back line (INT BACK L) will remain high until the actual vectoring takes place. After that, a low to high transition on the interrupt back line will cause the B section of the 7474 to shut off and stay off until either the interrupt enable or the UART done line is cleared and set again. As a convenience, any processor write operation to the status register will also reset the UART making the UART done line wait for the next character to be received.

The interrupt arbitration logic is in figure 5. Interrupt requests are arbitrated by the 74148 8 line to 3 line priority encoder. With the enable input (El) line normally low, the gate status (GS) output will go low when at least one of the inputs is low, signaling an interrupt request had been posted. The outputs of IC6 will be a binary encoding of the one's complement of the highest priority input signal that is asserted low. When the processor acknowledges the request, the proper vector information, which is made up of a combination of switch settings and 74148 outputs, will be put onto the bus through the 7438 bus drivers. See table 2 for an enumeration of the vectoring. Observe that the bus is at ground potential for an address bit of 1. At the same time, the D3 input to IC7 will go low asserting an output line corresponding to the interrupt. When the interrupt sequence is done, the D3 input goes high and the cor

122 February 1980 © BYTE Publications Inc

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BYTE February 1980 123

responding interrupt back line goes high clearing its respective D flip flop from figure 4. Simultaneously, IC8 is triggered to time out the gate status output of IC6. This is necessary because the remainder of the interrupt logic requires the gate status line to go high before it can be asserted to request another interrupt.

Unfortunately, there is a period of about

74148 Output

Interrupt

A2 A1 AO

Octal to 7442

Vector Offset

KBDO

L L L

0

+ 0

KBD 1

L L H

1

+10

KBD2

L H L

2

+20

KBD 3

L H H

3

+30

PRINTO

H L L

4

+ 4

PRINT 1

H L H

5

+14

PRINT 2

H H L

6

+24

PRINT 3

H H H

7

+34

Table 2: Vector table generated by the 74148 and 7442 (ICI and IC2 in figure 5) combination through the bus drivers.

50 to 100 ns when the bus drivers are active that a higher priority interrupt could perhaps sneak through IC6 and deskew the correct data. This problem could probably be eliminated by giving the higher communication rate terminals a higher priority or by using an extra set of latches.

If all the UARTs were driven off the same clock source, the interrupts could only occur simultaneously (in which case the arbitration works correctly) or at least spread apart by an interval equal in length to 16 times the transmission rate. This would be 26 /us at 2400 bps. Feeling that the odds of two people typing two keys within 100 jus of each other is quite small, the circuit remains as presented. The interrupt enable bits and the done flags are reported back to the user through 74153s, dual 4 line to 1 line data selectors. The input to these chips comes from the interrupt enable signals of the 7474s and from the UARTs directly.

INTERRUPT LINES

i INTERRUPT } BACK LINES

O INTERRUPT REQUEST LINE

BUS D07 LINE

BUS D06 LINE

BUS 005 LINE

BUS D04 LINE

BUS D03 LINE

BUS D02 LINE

BUS INTERRUPT SEQUENCE LINE

<zt>

-< I GRANT INTERRUPT

Figure 5: The interrupt arbitration logic interfaces the requests from the UARTs to the remainder of the bus interrupt sequence logic. Note that the 74148s can be wired in serial to control even more requests.

124 February 1980 © BYTE Publications lnc

An additional item: in trying to keep my costs to a minimum, my clock driver consisted of an NE556 dual timer and a 7493 divide by 16 counter instead of a MC14411 bit rate generator. Luckily, the NE556 was the only part not in my rather well stocked junk box at the start of this effort. The clock circuit is shown in figure 6. Current market price for four terminal interface boards for the PDP-11 is about $1600. This interface required some four months of spare time to design and debug. The time has been well worth the effort. My 20 mA teleprinter, operating at 110 bps, and my EIA modem, operating at 300 bps, are currently attached to this interface with two ports still open. Now I have a single terminal interface left over with no use for it. I guess I will have to find another terminal."

BIBLIOGRAPHY

1. PDP-11 Peripherals Handbook, Digital Equipment Corp, Maynard MA, published yearly.

2. Signetics Logic Data Manual, Signetics Corp, Sunnyvale CA, published yearly.

m

A7

ICI I

RESET NE556 VCC

DISCHARGE RESET

THRESHOLD DISCHARGE

TRIGGER THRESHOLD

OUTPUT TRIGGER

GROUND OUTPUT

Figure 6: This simple clock circuit will drive the UA R Ts at any reasonable speed between 110 bps and 2400 bps. The resistance values are approximate. Pin 9 on the NE556 is adjusted for 26 ijls and pin 5 is adjusted for 5 70 ijs.

OI/iF

OUTPUT(BPS) LZ>"°

O>l50 O>300 ■L3>600 CZ> IHOO

-d>2400

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February 1980 © BYTE Publicalions Inc 125

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BYTE February 1980 127

Comparison of Some High-Level Languages

Robert A Morris

Associate Professor

Department of Mathematics

University of Massachusetts

at Boston

Boston MA 02125

Different languages are appropriate for different tasks: multilingual ability is as useful in the computer world as it is in the human world.

The time is not far off when microprocessor users will begin the serious use of high level languages other than the BASIC supplied for many current machines. There are many projects hither and yon to implement contemporary languages in microcomputer form, and the emergence of 16 bit processors will probably accelerate this trend. Indeed, even now microcomputer users have a practical way to use high level languages: using the personal computer as an intelligent interactive editing terminal and sending source code over telephone lines to be compiled and executed by a large remote timesharing computer. For many such tasks, the connection time (the charge levied by the big computer operators for merely listening to your terminal) is a substantial fraction of the total cost. But this lime is short compared to the data entry time, which will be entirely on the user's own system.

Unfortunately, most information about languages is gleaned from people who have a stake in a particular language due to a greater familiarity with it. Different languages are appropriate for different tasks. Multilingual ability is as useful in the computer world as it is in the human world. To this end I would like to describe the differences and similarities between major general purpose programming languages, and offer opinions about how these differences might affect your choice of a high level language.

A number of the conclusions I draw can be attributed to questions of style, and many whose personal programming styles are different might take issue or even umbrage at what I offer. Nevertheless, I claim the critical reviewer's prerogative to offer opinion, and hope only that it is clearly identified. One precaution to the novice and to the initiate: In comparing programming languages, I assume that the specific choices are equally well implemented. Unquestionably the worst

version of language A may be far harder to use than the best version of language B, even if in principle the opposite is the case.

My own particular bias is that I am not interested in "number crunching": that is, the use of the computer for scientific or statistical calculations which are complex, lengthy (in terms of machine time), and which often run repeatedly with different data. For such so called production programs the programming expense is usually small compared with the computing expense, and there is a premium on efficient programs. Suppose one writes a program to solve a system of linear equations by Gauss' method with the principal intention of understanding that method. It then becomes irrelevant that an additional 10 hours of programming effort can produce a 50 percent increase in running speed. The program will run only a few times for a few seconds.

Finally, I admit I am a mathematician. Mathematicians think in unusual ways, especially about computers. I once baffled a computer professional when I told him that most of the programs I write, once written and correct, never needed to be run. Programming as a logical and esthetic discipline is not a very comfortable idea to many professionals. In any case, writing a program in order to understand an algorithm, instead of vice versa, is a commendable use of computers and one which colors my own thinking.

In many organizations some system of phantom money is in effect for computer use. The users and their departments often have budgets but do not spend any money. Rather they simply have some restriction put on their use if this budget is expended. Indeed it has been argued that certain computer use, like library use, should be completely without accounting. Nevertheless, it is common to talk of one or another solution being expensive, and this is to

128 February 1980 © BYTE Publications Inc.

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BYTE February 1930 129

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be understood as being a vague and relative term, taking into account such factors as computing charges, programmer's time and storage charges for data and programs in or outside the machine.

I will discuss essentially three languages: BASIC, FORTRAN, and ALGOL (together with PL/I). I'll also take a cursory look at Pascal and give a brief description of APL together with the reasons for not including it in this survey. These languages are fairly standardized so that if one has learned them on one machine, there is very little relearning necessary for another. Indeed, aside from minor punctuation differences, one rarely encounters machine dependent features of these languages except for input and output (10). Thus it is often practical to transport programs from one machine to another with very little rewriting except for the 10, but in some circumstances this can be substantial.

Many BYTE readers know BASIC already, but I will describe it so that a broader audience might be reached. In some of the following examples I have abused programming language punctuation in the interest of comprehensibility.

BASIC

BASIC is an acronym for Beginner's Allpurpose Symbolic Instruction Code. It was developed originally at Dartmouth University and designed as a conversational interactive language, meaning that the user is essentially in immediate and constant contact with the computer. A good BASIC translator will give some diagnostic messages even as the user types in the program. In any case the system will attempt to indicate to the user the point at which a linguistic error occurs. This is true for most high level languages whether conversational or not, but the conversational feature and the similarity of BASIC to ordinary mathematical notation make it a particularly easy language to learn and use. In fact, it is the language of choice when the program to be written is short, say 20 commands or less, and the manipulation no more than high school algebra. BASIC is typically available on the interactive minicomputers used in many high schools. It looks like this:

100 LETX=Y=3

200 LET Z=5

300 LETW=3*(X+(Y/2))

400 PRINTW

500 END

BASIC is an inherently expensive language in terms of time, because it is interpreted rather than compiled. This means that the program is translated into machine

130 February 1980 © BYTE Publications Inc

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language each time it is executed, rather than translated once and stored in machine form. The technical differences between interpreters and compilers are not otherwise relevant here. Roughly speaking, with an interpreter one does much less cajoling of the computer to get it to pay attention to one's program.

BASIC programs are easy to alter. To change a line, simply retype the offending line number followed by the new text, then a carriage return. The new line replaces the old and one can try to execute again. Thus, getting a program working right can involve very little waiting.

Many large computers operate in batch mode. This means that the user submits the program to the operator, typically on punched cards, and waits for it to be processed in turn. In such an environment the interactive feature is of no use. Although some batch systems have BASIC processors, it seems pointless to use the language this way.

For complicated problems, especially of a mathematical nature, BASIC has some severe deficiencies, even though it is probably the best first language to learn where it is available. One of the biggest of these is the difficulty of writing a BASIC program in pieces. "Passing parameters" can be a very messy business in BASIC and it is usually important to make sure that there is no confusion over the names of the variables. Generally, different variables must have different names, and the same variables the same name throughout a program. Fullyimplemented FORTRAN avoids these pitfalls (in a somewhat unnatural fashion), and in ALGOL and PL/I they cannot arise at all. The mathematician's penchant for calling all independent variables t or x may be freely indulged in ALGOL, cautiously so in FORTRAN, and not at all in BASIC. This is particularly important when one is writing general routines to be plugged into several programs which may not have even been conceived yet.

FORTRAN

FORTRAN looks like this:

l=2 J=3 K=l+J

WRITE(6,10) K 10 FORMAT(H)

The write statement, if mysterious, is at least formal and standard. It instructs the machine to write on output unit 6, probably a printer or the user's terminal, according to format statement 10, the present value of the variable K.

132 February 1980 © BYTE Publications Inc

Circle 82 on inquiry card.

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Respectable modern FORTRAN compilers allow the programmer the option of ignoring the format and outputting the results in some standard fashion.

FORTRAN stands for FORmula TRANslator. It is the oldest and most widely used language for scientific computing. FORTRAN compilers for most machines produce extremely efficient machine language programs because demand is so great and the language has such a long history. For this reason, also, there are many compilers with excellent diagnostic features, such as the University of Waterloo's WATFOR and WATFIV systems available for large IBM machines and even optimizing compilers which attempt to improve on the programmer's efforts.

However, as we shall see, some of the classic features of FORTRAN are the very ones that should make people shun it. But because it is so familiar, it is difficult to convince FORTRAN adherents that the language is detrimental to their efforts. Of course, for production programs, efficiency is a legitimate reason to use it. Writers of more ephemeral programs should be aware of the extent to which the other languages around them are being improved and be sure the sacrifices are needed. There are two major objections to FORTRAN: it is difficult to write readable programs; and it is difficult to structure programs in a logical way that reflects the programmer's mathematical ideas for the solution of the given problem. I do not claim that these tasks are impossible. But it is widely agreed that typical FORTRAN programs are unreadable. This is often caused by bad habits encouraged by the language. A common experience with large FORTRAN programs is that some months after writing one, even the program's writer must study it at length to find out how it works. For another reader, this job may be immense.

One of the main reasons for this is the way in which logical alternatives are considered and acted upon in FORTRAN (and BASIC, for that matter). One of the principal powers of a computer is its ability to alter its course of action according to conditions that may not be known at the time the program is written, but which may be known only when it is executed. In FORTRAN and BASIC the alternative course of action is numbered (in BASIC all statements are numbered) and a program may contain a statement such as IF (condition to be tested) THEN GO TO 55. If the Condition is not met, the computer executes the next instruction, but if it is met it executes the series of instructions which begins with

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February 1980 © BYTE Publications Inc 133

statement number 55. However, people never think in this way even if the alternative courses of action are too complicated to remember in detail. Instead of bearing in mind where the alternatives may be found, one always keeps in mind what they are, perhaps in some brief mnemonic form. Thus the ALGOL statement:

IF GCD(A,B)^1 THEN

P:=SMALLEST.COMMON.PRIIvlE.DIVISOR(A,B) ELSE

P:=MIN(A,B)

is surely more informative than the FORTRAN version:

IF (GCD(A,B).NE.D THEN GO TO 55

P=MIN(A,B)

GO TO 65 55. . . .code describing how to find smallest common prime 65 continuation of program

I am not suggesting that ALGOL knows how to find the smallest common prime. Of course, the words smallest.common. PRIME.DIVISOR(a.B) must also be defined in the program, just as they would at line 55 in the FORTRAN program. But the FORTRAN programmer, in the interest of intelligibility, must add comments, both at line 55 and at the appeal to it, telling the reader what is going on. The necessity of adding comments (words which explain the program to the reader but which are ignored by the computer) is a sign that the conventions of human thought have been sacrificed to the conventions of the programming language. This is a common occurrence in FORTRAN and almost impossible to avoid with the use of GOTO statements (see reference 6 for an exposition of this point and its history).

The second mathematical objection to FORTRAN is that dummy variables are somewhat restricted. They occur automatically in subprograms (small portions of a program which are executed repeatedly but each time with different values assigned to their parameters), but otherwise are essentially absent. This means that some care must be taken in writing complicated programs so that variable names are not confused. Because of this it is difficult to transport pieces from one program to another. A skilled FORTRAN programmer told me that his biggest headache is having to constantly rewrite the same algorithm. That favorite phrase of mathematicians "we are done because we are reduced to a previously solved case" is very difficult to put in practice in FORTRAN and BASIC but quite easy in ALGOL and PL/I. FORTRAN subprograms are not recursive.

That is, unlike their ALGOL counterparts, they cannot appeal to themselves in their own definition. This subtle difference can have extreme consequences in nonnumeric calculations, but this is beyond our scope.

ALGOL-like Languages

ALGOL is the ALGOrithmic Language developed around 1960 (a standard and quite commonly available version is called ALGOL 60). Originally intended as a language for specifying algorithms for publication, it is now widely implemented and used in scientific environments, especially in Europe. A portion of the language PL/I is similar to ALGOL, and the remarks below generally apply to it. Since PL/I is supported by IBM for its machines far more than is ALGOL, users of IBM equipment may prefer to keep it in mind. Pascal is a kind of second generation ALGOL 60 to which most of the comments in this section apply.

Simple ALGOL appears much like BASIC:

BEGIN

INTEGER X,Y,Z;

X:=3; Y:=2; Z:=X+Y; PRINT(Z); END.

This program does what the BASIC example does. The differences are in punctuation. ALGOL commands are separated by semicolons, whereas BASIC requires each to have a line number. ALGOL uses the symbol ■to assign a value to a variable while BASIC requires the theme let X=3 (though some versions make LET optional).

Most notable is that the type of each variable must be specified; in this example each variable is declared to be an integer. In BASIC no distinction is made between integers and real numbers, while in FORTRAN, if a variable name begins with (usually) l,J,K,L,M or N it is understood to be an integer. Otherwise it is a real variable with some understood accuracy convention (complex variables are also allowed in FORTRAN and most ALGOL implementations). These conventions can be overridden by the programmer, and readability need not be sacrificed in FORTRAN.

One main feature of ALGOL which makes it attractive for mathematical and logical problems is that it \sablock structured language. By definition a block is a piece of code that begins with BEGIN and ends with END. There may be blocks within blocks nested as deeply as physical limits imposed by the actual computer will allow. Within each block one may declare the names of variables which are to exist only within that block. These variables do not have any existence outside that block and indeed,

134 February 1980 © BYTE Publications Inc

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outside the block there may be other variables with the same name and they will not be confused. Consider the following program:

BEGIN

INTEGER X,Y;

X:=3;Y:=2;

BEGIN

INTEGER X,Z;

X:=6;Z:=X+Y; PRINT(X);PRINT(Z); END;

PRINT(X); END.

The variable X in the inner block bears no relation to the X in the outer block and references to it in the inner block behave as though there were no X in the outer block. The Y in the inner block, however, has not been declared there, so it refers to the next most global occurrence of Y: namely that in the outer block. This program will output:

68 3

The first two numbers are produced by the print statements in the inner block, the last by that in the outer block.

This example is a trivial illustration, but the reader will appreciate that no care whatsoever need be taken with the naming of those variables whose existence is not needed outside the algorithm of which they are part. For this reason, algorithms are easily transported from one program to another. The possible sources of confusion arising from these so called local variables are approximately the same as those arising in ordinary mathematical discourse: "the variable x here is not the same as the variable x in the previous section."

Another feature of ALGOL and PL/I that adds to the ease of structuring programs is the existence of condition testing phrases other than IF. For example, one may use the sequence WHILE . . . condition to be tested. . . DO... something. Not only is this close to our way of thinking, but it has surprising implications for the programming solutions which are naturally suggested by the language. Such structures have been urged for FORTRAN and may well be included in future versions. They are beginning to appear in nonstandard versions of FORTRAN already.

What are the disadvantages of ALGOL? Foremost is that even the most commonly used mathematical procedures are often not preprogrammed into the system as they are in BASIC and FORTRAN. Thus, although arrays are a standard data type in ALGOL, there are no matrix manipulation functions such as BASIC'S LET MAT A = B + C. The programmer is responsible for adding the routines to perform these operations. Because of the transportability we have

136 February 1980 © BYTE Publications Inc

discussed, this is not particularly difficult. In many systems, these routines could be stored on a high speed storage device such as a magnetic disk, easing the task even further. Thus, each programmer or group may have to build a library of standard routines, whereas in BASIC and FORTRAN large libraries are usually already provided.

These functions often include many transcendental functions and sophisticated procedures, but ALGOL libraries may contain little more than elementary functions. This is largely a historical development and may be expected to change as ALGOL becomes more widely used. This drawback is of little consequence if one's application is nonnumeric. At this writing I am programming procedures in ALGOL to calculate with polynomials over finite fields. Since it is too much to expect any library to have a routine to calculate the zeta function of a curve, I am not terribly restricted by the skimpy offerings of ALGOL libraries.

Even more consequential, because of its limited libraries, is the fact that ALGOL tends to require more programming effort for 10 than FORTRAN or BASIC. Simply getting numbers in and out is generally easy, but adjusting format or 10 of text may be a complicated task. 10 is at least standardized, if cumbersome, in FORTRAN and BASIC. However, 10 is not part of the official definition of ALGOL, which burdens it with machine dependent features.

Pascal

Pascal is a modern language derived from ALGOL 60 that addresses itself to a very important issue we have not dealt with so far in this elementary exposition: data structures.

Pascal allows the user to define and manipulate new types of data beyond the fundamental types (integers, reals, arrays, strings) which appear in the older languages. Further, it does so in a completely recursive fashion, which adds considerable power to this feature. These matters are beyond the scope of this article, but, as designed, Pascal is easy to learn, powerful and very much like ALGOL in nature.

APL

APL stands for A Programming Language. It is a high powered language designed to make the handling of matrices and vectors particularly easy, and as such it is very successful. Its adherents tend to be emphatic about its value as a general purpose language. My own view is that its array orientation is a disadvantage for structuring complicated

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„ THE . SOFTWARE SUPERMARKET

February 1980 © BYTE Publications Inc 137

programs unrelated to array handling. The language does not encourage the writing of readable programs. It is easy and tempting to write very compact, cryptic programs (however, this is a human decision and not really forced by the language). The present view of programming languages is that the elementary data and control structures of the language shape the programmer's way of thinking about solutions. Because of its underlying array orientation, I prefer to put APL with special purpose languages and omit it from this discussion, even though it is so widely used that it can not be regarded as an exotic language.

Exotic Languages

A number of special purpose languages and systems have arisen as the result of research in computer languages. An annual survey of languages is published by the Association for Computing Machinery.

Some of these special purpose languages, like the algebraic manipulation systems, may be particularly complex or difficult to use, although appealing to the mathematically

inclined. Others, while exciting in prospect, are only beginning to be implemented. Anyone wishing to explore these languages should first gain some traditional programming skill and establish a close relationship with the professionals at the computer center where you are using them, because the exotic products do not always behave as promised and sometimes need a little coaxing from the systems programmers.

Acknowledgements

None of the ideas expressed here is original. They have been percolating in the computer field for a few years, but apparently are still regarded by some as controversial. The names often associated with them are Dijkstra, Wirth, Knuth and Hoare, whose works set them out in detail. I thank Richard Palais for nudging me toward ALGOL and thence to a consideration of these ideas. I wrote this article using a computerized text formatter adapted from the RATFORMATter of Kemighan and Plaugher (see bibliography) who were the first to insist that there is such a thing as literacy in programming.

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5

138 February 1980 © BYTE Publications Inc

Circle 90 on inquiry card.

Getting Started

The bibliography which follows contains my own favorite introductory texts. Consult local opinion also, because personal explanation is one of the most useful tools in learning programming. If a particular book is highly regarded by people around you, your questions may be more easily answered by others familiar with it. Two other warnings are necessary: you cannot understand programming without writing and running programs; and be wary of the machine manufacturer's language manuals — they are often written for someone who already knows the language or some other high level language. But check them for minor differences with your text. With ALGOL you will probably have to learn the 10 from the manual."

10.

Science, number 184, May 31 1974, pages 957 thru 961.

McCracken, D D, A Guide to ALGOL Programming, Wiley, Somerset l\IJ. The problem with this and other ALGOL primers familiar to me is that they don't really discuss the features of ALGOL that make it powerful. But it is fine for getting started.

McCracken, D D, A Guide to FORTRAN IV Programming, Wiley, 1972. A widely used text. Included are excellent discussions on points of style and efficiency, and an appendix on the WATFOR and WATFIV compiler. They are often used at universities running IBM systems. They will ease the learning of FORTRAN, as will this book.

Weinberg, G M, PL/I Programming: A Manual of Style, McGraw Hill, New York, 1970. Yet another beginning.

11. Wirth, N, Systematic Programming: An Introduction, Prentice-Hall, Englewood Cliffs NJ, 1973.

BIBLIOGRAPHY

1. Kernighan, B and Plaugher, P, Software Tools, Addison-Wesley, Reading MA, 1976.

2. Dahl, 0 J, Dijkstra, E W, and Hoare, C A, Structured Programming, Academic Press, New York, 1972.

3. Floyd, R W, Introduction to Programming and the ALGOL W Language, Department of Computer Science, Stanford University. ALGOL W is an extension of ALGOL 60 written at Stanford for the IBM 360, and if you have it, you'll find this book particularly useful. If you are adventuresome, consider using it anyway, using the machine manufacturer's manual to sort out the differences. Like McCracken, it's just a beginning.

4. Jensen, K and Wirth, N, Pascal User Manual and Report, second edition, Springer-Verlag, New York, 1974. Not a programming primer, but definitely a Pascal primer. A small amount of any programming experience will suffice to read it (an all too brief introduction attempts to substitute for this experience). It also contains the "Report," the official definition of Pascal, which may prove interesting to those who have never seen such a document.

5. Kemeny, J G, and Kurtz, T E, BASIC Programming, Wiley, Somerset NJ, 1971. By the fathers of BASIC.

6. Knuth, D E, and Wirth, N,ACM Computing Surveys, volume 6, number 4, 1974. Special issue on programming with articles by these two authors and others.

7. Luehmann, A W, and Nevison, J M, "Computer Use Under a Free Access Policy,"

Also see Communications of the volume 19, number 12, 1976.

ACM,

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Circle 91 on inquiry card.

February 1980 © BYTE Publications Inc 139

Technical Fcpum

Some Example Plots

David Dameron 402 E OTCeefe St, Apt 27, E Palo Alto CA 94303

I have been reading BYTE since it was first published in 1975 and have enjoyed its articles, especially those on plotting graphics. My computer is a Cromemco Z80 with 48 K bytes of programmable memory and a 5-inch disk drive. This configuration gives about 20 K bytes of available user memory with 16 K BASIC. My plotter is a Sylvanhills DFT-2, run from a parallel port. I modified the plotter to use stepping-motor X,Y movements, under computer control after reading "Taking the First Step" (February 1978 BYTE, page 35). It now has 300 points per inch of resolution using 15-degree stepping motors.

After the basic vector control software was completed, one of the first routines I entered was a character generator: "A Plot is Incomplete Without Characters" (July 1976 BYTE, page 64). Inspired by "Venus de Plotto"

(February 1977 BYTE, cover), I entered various threedimensional routines, for example: "Hidden Line Subroutines for Three-Dimensional Plotting" (May 1978 BYTE, page 49). You can see that BYTE has greatly contributed to this plotting system.

The three-dimensional plot "Waves" (figure 1) is an example of the hidden line routines. There are 141 points in the X direction and 156 in the Y direction. It is the sum of four radially-damped sinusoidal waves rotated in three dimensions. The program took about 10 hours to run with a 4 MHz clock, divided evenly between point calculation and the actual plotting, which was done concurrently. Listing 1 is a chord program which produces the output in figure 2 (page 144).

This sample output took about 90 minutes to plot; a

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Figure 1: Three-dimensional wave program output which took 10 hours to produce.

140 February 1980 © BYTE Publications Inc

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Circle 92 on inquiry card.

BYTE February 1980 141

10

REM DRAWS PLL CHORDS WITHIN HN N

GON 7/16/76

240

U2=l : F=l

20

REM USES DIMENSIONS IN PLOTTER RRSTERS

250

N1=N

30

REM WRITTEN BY DRV ID H. DRMERON

260

IF I=N/2 THEN N1=I

40

REM INITIALIZE PLOTTER HERE.

270

REM J1=FR0M, J2=T0 POINT

50

INPUT"NUMBER OF SIDES? ",N

280

REM MAKE J1=PREVI0US J2 UNLESS

TAKEN (H(J1)=1)

60

DIM BCN),C(N)

290

REM IF TAKEN INCREMENT Jl TILL

1 FOUND, LIFT PEN

70

INTEGER I,J,H(N)

300

FOR J=l TO Nl

80

INPUT'RPDIUS OF PLOT? ",R

310

U1=U2

90

Pl=6.2831853/N

320

IF H(J1)=0 THEN 360

100

FOR 1=1 TO N

330

J1=J1+1 : IF J1>N THEN J1=U1-N

110

B(I)=R+10+R*C0S((1-1)*P1)

340

F=l

120

C(I)=R+10+R*SIN<(1-1)XP1)

350

GOTO 320

130

NEXT I

360

J2=U1+I

140

FOR 1=1 TO INTCN/2)

370

IF U2>N THEN J2=J2-N

150

REM DRAW LINES TO I'TH NEIGHBOR

380

H(J1)=1

160

FOR J=l TO N

390

REM F=l IS A FLAG TO LIFT THE

PEN

no

H(J)=0

400

REM IF F=l THEN MOVE TO B(J1)

C(J1) WITH PEN LIFTED

180

NEXT J

410

REM CALL VECTOR ROUTINE HERE.

190

IF I<>N/2 THEN 240

420

F=0

200

REM DRAW ONLY 1/2 LINES IF DIAMETERS

430

REM DRAW TO B(J2),C(J2) HERE.

INSERT VECTOR ROUTINE HERE.

210

FOR J=N/2+l TO N

440

NEXT J

220

H(J)=1

450

NEXT I

230

NEXT U

460

STOP

Listing 1: Program Chord produces a series of chords for a given circle. The sample output is shown in figure 2 (page 144). This listing was made hy the author's system using a plotter.

little backlash can be seen at the vertices of the 29-sided polygon. The listing was plotted on this system with characters four times the minimum size. This routine was written to remove some of the unnecessary plotter X,Y motion from that of just cycling through all the vertices for both the starting and ending points. Plotter routines should be inserted at lines 390 and 430 to suit a particular system. At 390, move to B(Jl), C(J1) with the pen lifted. At 430, draw a line to B(J2), C(J2) with the pen down. I use the system in my work plotting graphs and other

forms of data, and I hope to eventually sell some of the computer graphics I have produced. It is stimulating and fun to create various plot outputs on the spot, now that the hardware has been debugged and is running. The plotter output is not limited to ink drawings on paper. A needle or other engraving point may be mounted in the pen holder (a small clamp) for drawing etching lines in a zinc plate through a thin layer of an acid resisting substance. The plots can then be etched by dumping the plate in an acid bath for an appropriate time period.

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142 February 1980 © BYTE Publications Inc

Circle 93 on inquiry card.

A BUSINESS PROPOSITION

from

INTE3TEC DATA SYSTEMS

Dear Computer Enthusiast:

As a result of the phenomenal growth our company has experienced during the past year, there are now many excellent opportunities in our national dealership program. And as a result of this expansion in our dealership network, there are new employment opportunities in the marketing and technical divisions of our company. We'd like to talk about these opportunities for just a minute.

Our two major products, the InterTube II Video Terminal and the SuperBrain Video Computer are, to say the least, an overwhelming success. This widespread acceptance and demand for our products naturally requires the establishment and maintenance of a comprehensive dealer/service network. Many retailers and other microcomputer resellers have already joined our team. They are now realizing the true advantages our unsurpassed price/performance products can give them. How about you? Isn't it time you breathed a little new life into your operation? Dealership and OEM contracts are now being established in many areas. Call us today and discuss your requirements. You'll find us to be quite responsive.

Of course, our ability to successfully penetrate and maintain our position in this ever-increasingly competitive marketplace is due to the support of our many marketing, technical and service personnel. As our marketshare increases, so does our requirement for qualified personnel. We are presently recruiting marketing representatives to work closely with our dealers in the field. A sales/management background in this industry would qualify you for consideration for one of these positions. Also, we are in search of technical personnel to assist us here in South Carolina in supporting the varied applications our customers have for our products. At present, we are recruiting Basic, Fortran and Assembly language programmers as well as lab and production technicians.

Whatever your interests may be, dealership or employment, we urge you to carefully consider the advantages of association with our company. Pause for just a moment and give us a call at 803/798-9100. And if you don't believe us, ask the industry experts. They will tell you we're on the way to the top! So, why not join us now and enjoy the ride.

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Dear Intertec,

Yes, I'm interested! Please call me with more information about the opportunities I've checked below.

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The Marketing Department 2300 Broad River Road Columbia, South Carolina 29210

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Your name .

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Circle 94 on inquiry card.

BYTE February 1980 143

m

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Figure 2: Sample output of the Chord program written in BASIC. This figure took 90 minutes to produce.

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144 February 1980 © BYTE Publications Inc

How

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Circle 95 on inquiry card.

505 HAMILTON AVENUE PALO ALTO, CA 94301

BYTE February 1980 145

Circle 96 on inquiry card.

Zs - SYSTEMS

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Technical Fopum

Introduction to Code Tightening

Geoffrey Gass, 5240 SW Dosch Rd, Portland OR 97201

"Why should a programmer be so obsessed with pinching and scraping to save a few bytes of code?" asks the representative from Behemoth Computers Inc. In his part of the universe, whether a program takes 110,000 bytes or 120,000 bytes is of no particular moment.

"What a damned tangle!" echoes one of his customers. "Haven't they ever heard of top down programming?" His part of the computer universe is concerned with programs written and understandable by interchangeable programmers, so any new job applicant capable of peeling his own bananas can pick up where the last programmer left off at the time of his unfortunate starvation.

In a smaller part of the universe occupied by minicomputer users and programmers, "tightening up the code" very early became a necessary practice to get useful programs into more confined memory spaces.

An even cozier corner, of course, is that of the personal computer programmer, who may have to spend many hours in tightening, trimming and squeezing to get a couple of quarts of program into his one-quart memory.

The tightest quarters of all (they might be described as "two-by-two by you") are those occupied by the microprocessor programmer fitting useful programs and modules into read-only memories (ROMs) for dedicated systems or monitors. Read-only memories come in relatively small, fixed sizes. The first estimate of what can be done in a given size read-only memory is always excessive of course, but in any typical project the absolute hardware limits are set very early, and it's up to the programmer to get as many as possible of the originally promised features into the fixed module size.

If by chance there are a couple of no-operation instructions (NOPs) in the final coding, then there is immediate pressure to do some tightening and squeezing to add another feature or two. If, as is more probably the case, the first coding runs long, then there is more intense pressure to squeeze, pare, tighten and rewrite every conceivable way to get the program genie into the bottle. (Even if the hardware decision is reversed and the readonly memory space doubled, program expectations will be increased until they again overflow the assigned space. This is a corollary of Parkinson's law; it is amply verified.)

The successful programmer in this environment is the one who gets the job done. It takes a substantial repertoire of techniques and a good eye for spotting loose coding and redundant logic to do a succesful job of fitting the required functions into a fixed domain of memory. Though he may earn the scorn of the Behemoth man

FWX 710-985-5485

146 February 1980 IE) BVI h Publications Inc

Circle 97 on inquiry card.

Circle 98 on inquiry card.

CMPA

#20

BMI

CODIN

BEQ

DELIM

BGT

TEXTIN

("cheese-parer!") and the bitter enmity of the user who wants to reach in and borrow some of his subroutines, he wins in the marketplace when his product does more for less money, weight, power or space (or simply gets to the market sooner because of fewer hardware redesigns in the development cycle).

The object of this discussion is to present some of the tricks of the programmer's trade by which redundant logic and loose code can be tightened up to get maximum function into minimum memory space. But please heed the warning note at the end, lest you get yourself into a cleverness box from which there's no escape!

Redundant logic can be illustrated by the following sequence:

Compare ACCA to the value 20. Less than 20? Go to CODIN. Equal to 20? Go to DELIM routine. Over 20? Treat as text input.

Obviously, the last instruction is redundant. If the accumulator is not less than or equal to 20, it must be more than 20, and the third test is unnecessary. Frequently, the redundancy is more subtle, being determined by external parameters which make certain conditions impossible, and therefore unnecessary to test for.

Loose coding may be illustrated by this nice, straightforward top down subroutine for a 6800 string print operation:

PDATA LDAA 0,X Get data byte per index register.

CMPA #04 Check for EOT (string terminator).

BEQ EXIT If EOT, return to calling program.

JSR OUTEEE Not EOT. Output this character.

INX Step index register to next location.

BRA PDATA Go back for next byte.

EXIT RTS Return to calling program.

The routine uses 13 bytes. The sharp programmer notes immediately that it has two branches in it, one of them unconditional. An unconditional branch is always somewhat suspect in itself; in a short routine already containing a conditional branch, it's doubly suspect.

Here's how Wiles and Felix optimized the routine in Motorola's MIKBUG read-only memory. By moving the entry point to the middle of the routine, the unconditional branch can be thrown out and the loop closed by the conditional branch alone:

PDATA2 PDATA1

JSR OUTEEE Output the character. INX Step to next location.

LDAA 0,X Enter here. Get character per XR.

CMPA #04 Check for EOT.

BNE PDATA2 If not EOT, output the character. RTS Was EOT. Return to calling pro

gram.

Now we are down to 11 bytes. To save even more, the system could be changed to use 00 (NUL) rather than 04 (EOT) as the string terminator symbol. Because the N and Z bits of the condition code register in the Motorola 6800 respond automatically to a LOAD operation (this is not true of the 8080 and some other processors; you have to know the fine print to do a good job of code tightening), the comparison can be thrown out:

PDATA2 JSR OUTEEE Output the character.

INX Step to next.

PDATA1 LDAA 0,X Enter here. Get character per XR.

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Now, the job is all done in nine bytes, a 30 percent saving in code. (This trick could not be used in MIKBUG, since some of the strings contained NULs.)

For the read-only memory programmer, that could mean the difference between fitting and not fitting the allocated hardware. For the home hacker who handassembles his code it could be the difference between rewriting these few bytes and rewriting several pages of code (and risking a blowup if an address or offset is overlooked). It's not hard to guess which approach is best!

A Word of Warning

Here's a word of warning though: if you learn a lot of tricks and start applying them all in your original coding, there will be nowhere to tighten up if you run over. Your coding will also be much harder to understand later when you want to do something slightly different with it.

It's a little pathetic to see a routine loaded with twists, kinks, and convoluted logic, followed by a string of NOPs, revealing that the programmer was just performing logical games for his or her own amusement, or else swiped the routine from someone else without understanding it!

So, the best programming practice is to go with relatively loose and straightforward top down programming in the initial approach to a problem, and to save the tricks until you really need them.B

Mining the Skip Chain for Extra Bytes of Code

Geoffrey Gass, 5240 SW Dosch Rd, Portland OR 97201

Need bytes? Go where the code is, and start prospecting.

Somewhere, a program will probably be checking a value or input against several reference values, performing various actions according to the results of comparisons. A common filter construction uses a skip chain, a procedure which gobbles up a lot of code. This is therefore a good place to start a mine, smelter and refinery.

A typical skip chain might look like this (coding is for the Motorola 6800, but the process is essentially the same for all machines):

CTRL1

CTRL2

CMPA

#$18

Check for CANcel.

BNE

CTRL2

Not CAN? Skip next.

LDX

BUFAD

Was CAN. Get start point.

STX

BUFLOC

Reset "current" location.

BRA

BUFIN

Go get revised data.

CMPA

#$0F

Check for CTRL/0 (backspace).

BNE

CTRL3

Not CTRU0? Skip the following.

CPX

BUFAD

Was CTRL/0. Check current position in buffer.

BEQ

BUFIN

At start? Can't backspace. Forget it.

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BYTE February 1980 149

CTRL3

DEX

STX

BUFLOC

BRA

BUFIN

CMPA

#$12

BEQ

LININ

BRA

BUFIN

OK for backspace. Step back 1. New "current position." Go get corrected input. Check for CTRL/R (restart). CTRL/R? Start all over. All others, back to BUFIN.

There is nothing seriously wrong with the routine as shown, but it uses up 29 bytes in making three comparisons, and all of the operations but one end up by branching to BUFIN. Two of the BRA BUFIN instructions are unnecessary. Since all of the tests are for equality, the quantity in A is obviously going to match at only one test. So why bother jumping out early to avoid the other tests?

Another redundancy in this particular instance is not quite so obvious unless you see the rest of the routine. Note that in the CTRL2 sequence, a backspace is performed by decrementing the index register and putting the index register value into BUFLOC. Evidently, the index register carries the "current position" and is equal to BUFLOC when first entering the routine. There are two STX BUFLOC instructions in the routine. Could they be consolidated? The answer is yes, if we do not mind stuffing the index register into BUFLOC for all incoming codes. Try this:

CTRL1

CTRL2

CMPA

#$18

BNE

CTRL2

LDX

BUFAD

CMPA

#$0F

Check for CAN.

Not CAN? Skip.

Was CAN. Change XR content.

Check for CTRL/0 (backspace).

BNE

CTRL3

Not CTRL/0. Park XR and check for CTRUR.

CPX

BUFAD

Check position.

BEQ

CTRL3

At start? No backspace. Drop on through.

DEX

Step back 1.

STX

BUFLOC

New or old XR value.

CMPA

#$12

Final test, for CTRL/R.

BEQ

LININ

If CAN or CTRL/0, will fall through

BRA

BUFIN

All except CTRL/R, back to BUFIN.

CTRL3

Now the routine is down to 23 bytes: possibly a significant saving in a program being squeezed for memory space.

Note that what we are doing here is to trade redundant code for redundant operations, a frequently encountered tradeoff. To save a few bytes of code we have stretched execution time significantly. For keyboard interactive routines (as in the example), the execution time is unimportant. In a much used mathematics subroutine on the other hand (eg: multiple precision add or multiply), execution time will be much more important, since the subroutine may be called thousands of times in one calculation, and an optimum tradeoff would be more likely in the direction of code redundancy to gain speed of execution (counting machine cycles, not bytes of memory).

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BYTE February 1980 151

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"ca"'o„s

Personal Information Management System

For business and for pleasure. Increase your personal capabilities . .. save money .. . improve your ability to plan . . . locate important facts quickly. PIMS is a ready-to-use information (data base) management system for computers like theTRS-80, PET, etc. Have your computer manage tax deductions, department store charges, plan your day. Use it to keep your mailing list, do simple accounts receivable and payable. And much more! Includes easy-to-read manual and source listing. Written by the SCELBI staff. Only $9.95 No. 10

Introduction to

Low Resolution Graphics

Now you can produce amazing computer graphics — even if you can't draw a straight line. Literally! Learn how to draw lines and shapes, make graphs, draw pictures and even do animations. The simple secrets of how to do all this are contained in this new book by Nat Wadsworth. You'll be able to produce a deck of playing cards ... a clown that winks ... a football grid . . . and an animated football game. Also tells how to synchronize computer-generated sounds to your illustrations.

Just $9.95 No. 65

I J

Understanding Microcomputers

Accepted as the standard! 300 page easy reading text. Explains exactly how a microprocessor works. Intro to programming in BASIC. Complete glossary. Just $9.95 No. 90

Microcomputer Potpourri

A pocket-size reference for the beginner and pro alike. Full digest on understanding microcomputers. Data and diagrams on all the popular chips. Glossary. Only $2.95 No. 70

Learn Micro-Computers

A new multi-media information package for the beginner. You get Understanding Microcomputers book plus high-quality cassette. Great for self-study. Just $14.95 No. 40

UNDERSTANDING MICROCOMPUTERS

MICRO COMPUTER

UNSiSMNDMG

MEBQ

POTPOURRI

152 BYTE February 1980

6 *&*

&?££?*»** *^$j

Calculating with BASIC

Use your computer to calculate home mortgage payments, interest rates, payback periods and more! Shows how to apply the BASIC language to practical problems and equations. Covers the fields of mathematics, finance and statistics, mechanical engineering and electronics. For fun, the games of Hangman and Space Capture are provided. Written by Raymond Guido. Ideal for the businessman, scientist, engineer or student. Complete routines are worked out and ready for you to use. Just $7.95 No. 30

Z80, 8080, 6800 & 6502 Software Cookbooks

There's one for each of these popular microprocessors. With the right SCELBI Gourmet Guide and Cookbook, you'll be able to put together programs without having to start from scratch. You'll have the most useful routines at your command — already programmed and ready-to-use. Search and sort routines. Many general purpose utility routines. I/O and interrupt programming. How to control and manipulate stacks. Code and numeric conversion routines. Plus more! For 6502, No. 99, $10.95; for 6800, No. 50, $10.95 for 8080, No. 60, $10.95; for Z80, No. 75, $14.95

Z80 Instruction Handbook

Convenient pocket size guide to the powerful Z80 instruction set. Machine codes presented in octal and hex format. Instructions also indexed alphabetically. Only $4.95 No. 20

Z80

INSTRUCTION HANDBOOK

Free catalog

10 pages of books for business or pleasure. No. AA

See SCELBI books at your favorite computer or electronics store, or use coupon for direct mail.

J"" SCELBI Publications

Si) 20 Hurlbut Street, Elmwood, CT 0611 0

IMPORTANT ORDERING INFO! Include $1.00 shipping/handling charges for each item. Prices shown are for North American customers. Master Charge, VISA, Postal and Bank Money Orders preferred. Allow 4 weeks for delivery.

□ No. 10 DNo. 20 DNo. 30 □ No. 40

□ No. 50 DNo. 60 DNo. 65 DNo. 70

□ No. 75 DNo. 90 DNo. 99 □ No. AA

Name (please print)

Card No.

Bank No.

Address

City/State

Signature

. Exp. Date

Zip

. Date .

Circle 104 on inquiry card.

BYTE February 1980 153

Event Oueue

FEBRUARY 1980

February 6 Invitational Computer Conference, Ft Lauderdale FL. This conference is directed to the quantity buyer and will feature the newest developments in computer and peripheral technology. Contact B ] Johnson and Associates, 2503 Eastbluff Dr, Suite 203, Newport Beach CA 92660.

February 12-14

Data Communications Conference and Exhibition, Harbour Castle Hilton, Toronto Ontario, Canada.

Panel sessions, presentations, workshops, and technical sessions related to the field of data communications will be featured. Network control, management,

performance and architecture; communications hardware and software; fiber optics; distributed data processing; and international communications policies are some of the subject areas that will be discussed.

The exhibition at the convention center will feature over 100 exhibitors.

For more information, contact Whitsed Publishing Ltd, Suite 2504, 2 Bloor St W, Toronto, Ontario M4W 3E2 CANADA.

February 11-13 Programming the 6502 in Machine and Assembly Language, George

Washington University, Washington DC. This course is aimed at engineers, scientists, mathematicians and students who need to learn

CATCH THE

S-100INC.

BUS!

Shugart SA400 w Cabinet & AC Power Supply Kit

Integral Data Paper Tiger Model w/Graphics

Integral Data Paper Tiger Model w'o Graphics

Godbout Active Terminator Kit

D.C. Hayes Micromodem 100 Assembled & Tested

Intertec's Intertube 80x25 U/L Case

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Subiect to Available Quantities • Prices Quoted Include Cash Discounts.

Shipping & Insurance Extra.

We carry all major lines such as

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how to develop specialpurpose microcomputer systems for their own use. Familiarity with FORTRAN or BASIC will be helpful. For more information, contact Director of Continuing Engineering Education, George Washinton University, Washington DC 20052, (202) 676-6106.

February 11-13

Configuration Management,

George Washington University Washington DC. The objectives of this course are to review the impact of latest Department of Defense directives and instructions in the configuration management (CM) area; explain policy for practical applications; and clarify the role of CM in meeting program/project objectives. Engineers, program managers, production, quality control, and purchasing people are invited to attend. Familiarity with the contents of MIL-STD-480 is a prerequisite. Contact the Director, Continuing Engineering Education, George Washington University, Washington DC 20052, (202) 676-6106.

February 13-15

The IEEE International Solid State Circuits Conference,

San Francisco CA. This conference is a forum for the presentation of advancements in every aspect of solid state circuits. It will cover design, performance, fabrication, testing, and applications in digital, analog, microwave, and other areas of new solid state circuits,

device structures, phenomena and systems. For more information, contact Lewis Winner, 301 Almeria Ave, POB 343788, Coral Gables FL 33134.

February 18-21

European Information Management Exhibition and Conference, Wembley Conference Centre, London England. This show will exhibit microcomputer systems and peripheral items with demonstrations and applications focused on problem solving for the management executive. Contact Expoconsul, 420 Lexington Ave, New York NY 10017.

February 22-23

Louisiana Computer Exposition, University of Southwestern Louisiana, Lafayette LA. This conference is entitled "Distributed Systems Based on Mini and Micro Computers." It will cover programming languages, operating systems, evaluation of distributed systems, design criteria for distributed systems, and other related topics. There will be exhibitions of equipment and papers will be read and discussed. For more information, contact the Computer Science Dept, University of Southwestern Louisiana, POB 44330, Lafayette LA 70504.

February 25-27

Communication Networks '80, Shoreham Americana Hotel, Washington DC. This conference and exposition

In order to gain optimum coverage of your organization's computer conferences, seminars, workshops, courses, etc, notice should reach our office at least three months in advance of the date of the event. Entries should be sent to: Event Queue, BYTE Publications, 70 Main St, Peterborough NH 03458. Each month we publish the current contents of the queue for the month of the cover date and the two following calendar months. Thus a given event may appear as many as three times in this section if it is sent to us far enough in advance.

154 February 1980 © BYTE Publications Inc

Circle 105 on inquiry card.

THE ORIGINAL MAGAZINE FOR OWNERS OF THE TRS-80™* MICROCOMPUTER

SOFTWARE

FOR TRS-80"

OWNERS

H

CQMPUTBQMCS

MONTHLY NEWSMAGAZINE

Practical Support For Model I & II

MONTHLY

NEWSMAGAZINE

FOR TRS-80"

OWNERS

PRACTICAL APPLICATIONS BUSINESS

GAMBLING • GAMES EDUCATION PERSONAL FINANCE BEGINNERS CORNER NEW PRODUCTS SOFTWARE EXCHANGE MARKET PLACE QUESTIONS AND ANSWERS PROGRAM PRINTOUTS AND MORE

■ ■ ■

PROGRAMS AND ARTICLES PUBLISHED IN OUR FIRST 12 ISSUES INCLUDE 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

SQUARE ROOTS AND TRIGONOMETRIC FUNCTIONS)

NEW DISK DRIVES FOR YOUR TRS-80"

PRINTER OPTIONS AVAILABLE FOR YOUR TRS-80"

A HORSE SELECTION SYSTEM"*ARITHMETIC 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

AND CASSETTE TIPS. PROGRAM HINTS. LATEST PRODUCTS

COMING SOON (GENERAL LEDGER, ACCOUNTS PAYABLE AND RECEIVABLE. FORTRAN 80. FINANCIAL APPLICATIONS PACKAGE, PROGRAMS FOR HOMEOWNERS. MERGE TWO PROGRAMS. STATISTICAL AND MATHEMATICAL PROGRAMS (BOTH ELEMENTARY AND ADVANCED) AND

NOTICE

Pursuant to a consent judgement entered in the United States District Court for the District of Massachusetts, H & E Computronics, Inc. hereby gives notice that it is not and has never been an authorized Radio Shack dealer or outlet, that products or services offered for sale or sold by it are not and were not approved or warranted by Radio Shack or Tandy Corporation, and that only products or services purchased directly from Radio Shack or its authorized retail outlets carry the warranty of Radio Shack and Tandy Corporation. If you have placed an order, still outstanding, with H & E Computronics, Inc., for products or services, in the belief that those products or services were manufactured, approved or warranted by Radio Shack or Tandy Corporation, you may cancel that order and obtain a full refund of any money paid or deposited, simply by writing to the address below.

&&

WORD PROCESSING PROGRAM (Cassette or Disk)

For writing letters, text, mailing lists, etc., with each new subscriptions or renewal.

LEVEL II RAM TEST (Cassette or Disk)

Checks random access memory to ensure that alt memory locations are working property. DATA MANAGEMENT SYSTEM (Cassette or Disk) -Complete file management (or your TRS-80"

SEND FOR OUR 36 PAGE SOFTWARE CATALOG (INCLUDING LISTINGS OF HUNDREDS OF TRS-80" PROGRAMS AVAILABLE ON CASSETTE AND DISKETTE). $2.00 OR FREE WITH EACH SUBSCRIPTION OR SAMPLE ISSUE.

CQnPLITfiQMICS

Box 149 New City, New York 10956

ONE YEAR SUBSCRIPTION $24

START MY SUBSCRIPTION WITH ISSUE _ NEW SUBSCRIPTION RENEWAL .

TWO YEAR SUBSCRIPTION $48

HOUR 24 ORDER

LINE (914) 425-1535

SAMPLE OF LATEST ISSUE $4

(HI July 1978 • »7-January 1979 • »12 June 1979 • »18 January 1980)

CREDIT CARD NUMBER

SIGNATURE

NAME

ADDRESS

.EXP DATE.

*** ADD S6/YEAR (CANADA, MEXICO) ADD $12.YEAR AIR MAIL"OUTSIDE OF U.S.A.. CANADA & MEXICO «*•

* TRS-80T" IS A TRADEMARK OF TANDY CORPORATION

Circle 106 on inquiry card.

BYTE February 1980 155

wiJJ cover business communications. For program information, contact the Director of Program Development, The Conference Company, 60 Austin St, Newton MA 02160. For exhibit information, contact the national sales manager, Communications Networks '80, POB 96, Haddon Heights NJ 08035.

February 25-27

3rd International Learning Technology Congress and Exposition, Sheraton

Washington Hotel, Washington DC. Applications and technologies for the use of microcomputers and video disks as well as traditional technological issues in education and training will be discussed. In addition to the technical sessions, exhibits will range from video disk and mediabased systems to computerbased instruction systems. Contact the Society for Applied Learning Technology, 50 Culpeper St, Warrenton VA 22186, (703) 347-0055.

February 25-27

Microprocessor Peripherals Workshop, Montgomery AL. This hands-on workshop includes 27 hours of instruction, with a takehome option and one microcomputer station for every two participants. Contact Paul A Willis, POB 29, Arlington VA 22210.

February 25-28

Compcon '80, Jack Tar Hotel, San Francisco CA. The conference theme is "VLSI: New Architectural

Someday tM won't foe a phone without one.

-and under $199.

The only way to realize the full potential of your small business or personal computer is to tie it in with other computers. And the best way to do that is with a Cat acoustic modem.

A Cat modem lets your computer talk face to face with any other compatible computer or terminal within reach of your phone, over standard telephone lines.

You can work at home using the computer at your office. Send or receive data from anywhere. Or swap programs.

Fast, accurate, reliable

Cat. Someday there won't be a computer without one.

Novation

Tie your computer into the world.

Call for details

(800) 423-5410

In California (213) 996-5060

Available at Hamilton/Avnet, Kierulff Electronics, Byte Shops, Computerland,

and your local computer store.

Novation, Inc., 18664 Oxnard Street, Tarzana, California 91356

Horizons." It will be devoted to developing advanced technologies for computers. Contact Compcon Spring '80, POB 639, Silver Spring MD 20901.

February 26-28

Nepcon West '80, Anaheim Convention Center, Anaheim CA. The conference and exhibit will deal with the latest advances in electronics by covering such topics as wave soldering, etching, automated assembly, die attaching, hybrid circuit packaging, photo lithography, precious metal recovery, laser annealing, and much more. For further information, contact ISCM Inc, 222 W Adams St, Chicago IL 60606.

February 26-29

Office/Korea/80, Korea Exhibition Center, Seoul Korea. Exhibits at this exposition will include the range of products needed in offices from computers, word processing equipment and software to stationery, supplies, furniture and services. Information about the show may be obtained from Expoconsul, a division of Clapp and Poliak, 420 Lexington Ave, New York NY 10017.

February - August

Microprocessor Design Courses. The course is aimed at professional design engineers and covers fundamentals of microprocessor operations, programming, architecture and input/output integration. It will also cover Z80 and 8085 processors, working with the STD BUS and the designing and documenting of software. Tuition for the course is $400. The courses will be held in major cities throughout the US. Contact Elma Barnes, PRO-LOG, 2411 Garden Rd, Monterey CA 93940, or phone (408) 328-4745.

MARCH 1980

March 1

Exploring Small Computers,

156 February 1980 © BYTE Publications Inc

Circle 107 on inquiry card.

I

I

'Security... for your S-100 hard disk data'

The availability of fast, reliable, high capacity hard disk storage for the S-100 computer market has created a wave of excitement. It has also underscored the somber necessity for a reliable means of backup. No serious application is practical without a dependable, economical method for backup and archiving of critical on-line data.

Now, CSSN breaks the barriers to hard disk applications by offering the complete solution for data security ... a cartridge tape drive (13.4 megabyte capacity), fully S-100 interfaced, and software to make it work.-BACKUP IS NOW A REALITY!

Put your valuable data on-line with a hard disk... Save it off-line with our Back-Up Solution

Circle 108 on inquiry card.

COMPUTER SERVICE SYSTEMS NETWORK

120 0OYLS1ON STREET • FOURTH FIOOR- DOSION, MASSACHUSETTS 02116 • (617) 482-2343 • TWX (710) 321-1913 INCORPORATED

Albion College, Albion MI. This fair will feature exhibits and seminars on microcomputers and their applications in business, education, and the home. Contact D W Kammer, Dept of Physics, Albion College, Albion MI 49224.

March 3-5

Office Automation Conference, Georgia World Congress Center, Atlanta GA. A combination conference and exhibition of office computer systems has

been developed to help management understand the growing technology of business computer systems. For more information, contact H A Bruno and Associates Inc, 78 E 56th St, New York NY 10022.

March 4 and 5

8th Annual Midwest Digital Equipment Exhibit and Seminar, Thunderbird Motel Minneapolis MN. Manufacturers of computer terminals, data communication equipment, peripherals, data

acquisition systems and digital test instruments will display their products. Seminars will be held both days. For further information, contact John Bastys Countryman Associates Co, 1821 University Ave, St Paul MN 55104.

March 6-8

Microprocessor Peripherals Workshop, Chattanooga TN. See February 25-27 for details.

March 10-12

1980 National Office Exhibi

64KB RAM MEMORIES

LSI-11 - $750.00 • SBC 80/10 - $750.00 S-100 - $750.00 • 6800 - $750.00 • 6800-2 - $995.00

Illlla ap■

iiiiiiiii

§■■ ii'iiii in ■ ill Si

CI-6800-2 64K x 9

SiUiUl 11illill

CI-S100 64KX8

■ mini

■ ■■■■Mi ■iiilini 'liiiiiii

B

CI-1103 32KX 16

CI-6800 64K x 8

CI-8080 64K x 8

CI-6800-2 — 16KB to 64KB. Plugs directly into Motorola's EXORciser I or II. Hidden refresh up to 1.5 Mhz. Cycle stealing at 2 Mhz. Addressable in 4K increments with respect tc VXA or VUA. Optional on Board Parity. 64K x 9 $995.00.

CI-S100 — 16KB to 64KB. Transparent hidden refresh. No wait states at 4 Mhz. Compatible with Alpha Micro and all Major 8080, 8085 and Z80 Based S100 Systems. Expandable to 512 K bytes thru Bank Selecting. 64K x 8 $750.00.

CI-1103 — 16KB to 64KB on a single dual height board. On board hidden refresh. Plugs directly into LSI 11/2, H11 or LSI 11/23. Addressable in 2K word increments up to 256 K Bytes. 8K x 16 $390.00. 32K x 16 $750.00.

CI-6800 — 16KB to 64KB on a single board. On board hidden refresh. Plugs directly into EXORciser I and compatible with Rockwell's System 65. Addressable in 4K increments up to 64K. 16K x 8 $390.00. 64K x 8 $750.00.

CI-8080 — 16KB to 64KB on a single board. Plugs directly into MDS 800 and SBC 80/10. Addressable in 4K increments up to 64K. 16 KB $390.00. 64K $750.00.

€

Test and burned-in. Full year warranty.

Chrislin Industries, Inc.

Computer Products Division

31352 Via Colinas • Westlake Village, CA 91361 • 213-991-2254

tion and Conference,

Automotive Building, Exhibition PI, Toronto Canada. Subject areas of the conference will include energy conservation, small business computers, micrographics, word processing, telecommunications, copiers, office landscaping, and many others. There will be approximately 100 exhibitors presenting their products and giving demonstrations.

For more information, contact Whitsed Publishing Ltd, Suite 2504, 2 Bloor St W, Toronto, Ontario M4W 3E2 CANADA.

March 14-16

West Coast Computer Faire,

Civic Auditorium and Brooks Hall, San Francisco CA. An expected 15,000 attendees, over 340 exhibits, and more than 100 conference speakers will highlight this year's program. Exhibitor and speaker information may be requested from the Computer Faire, 333 Swett Rd, Woodside CA 94062.

March 17-20

Interface '80, Miami Beach Convention Center, Miami Beach FL. This conference and exposition is devoted to data communications, distributed data processing, and networking. Approximately 1000 exhibitors are anticipated and attendance is expected to exceed 12,000. For information, contact Interface '80, 160 Speen St, Framingham MA 01701.

March 17-21

Applied Time Series Analysis, University of California at Los Angeles CA. This course is designed for engineers, scientists, programmers, economists and other users of digital time series who require modern methods of data analysis using the fast Fourier transform (FFT), digital filtering, power spectral densities and correlation functions. The lectures cover topics relating to the Fourier transform, sampling linear systems, convolution, covariance, digital filtering,

158 February 1980 © BYTE Publications Inc

Circle 109 on inquiry card.

• ?"*">?!*

*r*?«T

CJ®

W-^

The line your reputation should be on.

When a computer supplier or retailer sells equipment, his reputation is on the line.

And when the customer has to justify his investment decision, his reputation is on the line too.

So, naturally, everybody's a lot better off on a reliable line. Like ours.

With a name like Industrial Micro Systems, we wouldn't think of building anything short of industrial standards... even our S-100 products. No short cuts or jumpers.

All of our boards —CPU, memory and controllers — are made from real fiberglass instead of a plastic substitute. And contacts are gold plated over a copperion barrier of nickel.

Every disk enclosure features a heavy-gauge steel chassis, and a heavy duty power supply. Built to take it.

Then come our complete systems. Aside from the disk drives, we manufacture every component that goes into them. Even the desk that goes around them. So

we can vouch for rugged reliability inside and out. Two complete systems:

Our new Series 5000 features a megabyte of storage on integral mini-floppies. And our Series 8000 is all business too. It can handle up to three megabytes on 8-inch drives. A large library of software, growing daily, includes CP/Mf PASCAL, and FAMOS?* Breaking the 64k barrier.

Using Industrial Micro Systems 32k memory boards with Memory Management, our systems can handle up to 576k RAM internally. More in store.

That's not the end of the line. It's growing all the time, along with our reputation for quality. Put your reputation on the line. Our line.

For more details just call or write. Supplier/dealer inquiries welcomed.

Industrial Micro Systems, 628 N. Eckhoff, Orange, CA 92668.(714) 978-6966

INDUSTRIAL MICRO SYSTEMS

The great unknown.

Trademark of Digital Research "Trademark of MV/T Systems

Circle 110 on inquiry card.

BYTE February 1980 159

power and cross-spectral density functions, and introductions to new methods in spectral analysis and rotating machinery analysis. For more information, contact UCLA Extension, 10995 Le Conte Ave, Los Angeles CA 90024.

March 20 Electronic Road Shows,

Castaways Restaurant, Burbank CA. This traveling exhibition of components, materials, and instruments is being produced by the Electronic Representatives Association (ERA). Over eighty ERA member firms will participate, and products from over 700 electronic companies will be displayed. For more information, contact the Southern California ERA office 20969 Ventura Blvd, Suite 9, Woodland Hills CA 91364.

March 24-26 Data Entry Management and Supervision Seminar, Cherry Hill NJ. This course deals with the practical aspects of data entry, and the problems encountered that are common to supervisors and managers. Concepts, techniques, motivation, training, and productivity will be covered. The fee is $415 for subscribers of MIC publications and $445 for nonsubscribers. For more information, contact MIC, 140 Barclay Ctr, Cherry Hill NJ 08034.

March 24-28

Fourth European Conference on Electrotechnics, Stuttgart. This conference will review recent developments, trends, and applications in the field of microelectronics. Microprocessors, computer communication, industrial electronics applications of microelectronics in the automobile and in medicine, and other topics will be covered. The conference language will be English. Contact Professor Dr W E Proebster, IBM Deutschland

GmbH, Postfach 80 08 80, D-7000 Stuttgart 80 GERMANY (BRD).

March 26-28 Viewdata '80, Wembley Conference Centre, London England. Viewdata 80 is an international exhibition and conference on video-based systems and microcomputer industries. The British Post Office is presenting the Prestel Show which is about electronic mail services. Contact TMAC, 680 Beach St, Suite 428, San Francisco CA 94109.

March 30 Greater Baltimore Hamboree and Computerfest,

Maryland State Fairgrounds, Timonium MD. Personal, dealer, and small business computer displays and exhibits will be featured. Space is available outside for tailgate sales and swaps. For more information, contact Joseph Lochte Jr, 2136 Pine Valley Dr, Timonium MD 21093.

March - lune

Computer and Office Systems Expo and Conference. This is an exposition for marketers of office systems equipment. The show and conference will focus on the local problems and opportunities of each region. The exposition and conference will be held in major cities around the nation. Contact The Conference Co, 60 Austin St, Newton MA 02160, or phone (617) 964-4550.

APRIL 1980

April 1 and 2

Southeast Printed Circuits and Microelectronics Exposition, Sheraton-Twin Towers Convention Center, Orlando FL. This show is a specialized event devoted entirely to the packaging, production and testing of printed circuits, multilayers, semiconductor devices, and hybrids

in the Southeast. Conferences are aimed at electronics specialists. Contact ISCM, 222 W Adams St, Chicago IL 60606.

Afjril 9-11

The Practical APL Conference, Washington DC. This conference is addressed to business executives and systems designers. For more information, contact Joan Gurgold, STSC, 7 Holland Ave, White Plains NY 10603.

April 9-11 International Conference on Acoustics, Speech and Signal Processing, Fairmont Hotel, Denver CO.

The IEEE Acoustics, Speech and Signal Processing Society is sponsoring this conference devoted to experimental and theoretical aspects of signal processing, speech, and acoustics. For more information, contact IEEE, 1100 14th St, Denver CO 80202.

April 11-12

10th Annual Virginia Computer Users Conference. This conference is sponsored by the Virginia Tech ACM student chapter. The topics of discussion will be programming languages and system and personnel management. For more information, contact VCUC10, 562 McBryde Hall, VPI&SU, Blacksburg VA 24061.

April 13-16

A Gateway to the Use of Computers in Education, Chase Park Plaza Hotel, St Louis MO. The purpose of this convention is to provide a forum for the exchange of information and ideas between individuals, to inform educators of developments in computer technology, and to expose participants to innovations in computing which can be utilized in the field of education.

Educators are encouraged to exhibit and make presentations of instructional microprocessor materials

during the convention. Contact the Association for Educational Data Systems (AEDS), POB 951, Rolla MO 65401.

April 14-18

High-Speed Computer Organization, 6266 Boelter Hall, UCLA Extension, Los Angeles CA. This course is for computer designers, system architects, project leaders and managers. The course provides an understanding of the principles of high-speed computer organization and their use in cost-effective systems. Several commercial and paper high-speed computers are presented and compared.

For more information, contact UCLA Extension at POB 24901, Dept K, UCLA Extension, Los Angeles CA 90024.

April 21-25 National Micrographics Association 29th Annual Conference and Exposition,

Sheraton Center Hotel and Coliseum, New York NY. The theme for the show is "Focus on Productivity in Office Management." Highlighting the conference and exposition will be presentations and talks concerning the use in offices for computer systems and related items.

For more information, contact the Conference Dept, National Micrographics Association, 8719 Colesville Rd, Silver Spring MD 20910.

April 23-25 International DP Training Conference, Hyatt Regency, Chicago IL. The theme for this event will be "The 1980s: The Information Decade." The conference is a symposium for data processing experts and corporate training executives. For information, contact Deltak Inc, 1220 Kensington Rd, Oak Brook IL 60521. ■

160 February 1980 © BYTE Publications Inc

MICROSOFT CONSUMER PRODUCTS

CONTINUING THE MICROSOFT TRADITION

Microsoft set the standard in microcomputer system software. We know more about the structure and capabilities of today's microcomputers than anyone else. And now we're using that power in a whole new way!

Announcing Microsoft Consumer Products. Distinctive software packages backed by the Microsoft name. Each is created by a top-notch programmer and comes to you fully documented, at a cost you can afford.

Microsoft Editor/Assembler-Plus." Now get every feature of Radio Shack's Editor/Assembler andT-Bug all in one package. PLUS—many "big computer" features to simplify your programming, editing and debugging. All in a low cost cassette package. Don't waste time creating both source and object tapes—Assembler-Plus assembles directly into memory. Supports macros and conditional assembly, too. Editor-Plus simplifies editing with extra commands like Substitute, Move, Copy and Extend. And Z-Bug,'" the most powerful debugger ever available for the TRS-80, has single step execution, direct execution in calculator mode and symbolic references. And, you can use up to 8 breakpoints at a time, with no need to remove a breakpoint before proceeding. For the 16K, Level II, cassette TRS-80. Priced at $29.95.

Microsoft Adventure. Only Microsoft offers Adventure complete, as originally written for the DEC PDP-10, now implemented on personal computers. The ultimate fantasy/logic game. Adventure allows you to explore the depths of the "Colossal Cave',' collecting treasures and magic, solving puzzles, avoiding hazards and adversaries—including the dreaded killer dwarves. Don't be fooled by imitation or incomplete versions. Only Microsoft has it all. Adventure fills an entire disk with everything you need for your exploration. Written by Gordon Letwin, of SOFTWIN, Associates. Adventure for the TRS-80 requires a single-disk, 32K system. For the Apple II,** a single-disk, 32K system with either the standard disk or language card system. For just $29.95.

Microsoft Typing Tutor. There's no easier way to master your keyboard! Faster and more efficient than any other teaching method, Typing Tutor helps you if you're starting from scratch or simply building speed. The secret lies in Typing Tutor's exclusive TRM'" or "Time Response Monitoring" software. TRM monitors your keyboard 20 times per second so the computer can evaluate your skill. Your speed. Your errors. Your weakest keys. Typing Tutor tells you where you stand then automatically adjusts itself to help you improve. Written by Dick Ainsworth and Al Baker of the Image Producers, Inc. For the Apple II with 16K and Apple BASIC or the TRS-80 with 16K and Level II BASIC. Priced at $14.95.

Microsoft Level III BASIC. Upgrade your Level II TRS-80 and increase your programming efficiency without additional hardware. Microsoft Level III loads from cassette tape on top of the Level II ROM. It gives you every feature of Disk BASIC except disk file commands. But that's not all—Level Ill's highspeed graphics turn your TRS-80* into a virtual electronic drawing board. And there's program renumbering, long error messages, quick shift-key entries, time-limit INPUT statements and many more features. System requirements: Level II BASIC and 16K. Occupies 5.2K RAM. Priced at $49.95.

Where To Buy. Microsoft Consumer Products are sold by computer retailers nationwide. If your local computer store doesn't have them, call us. Phone [206] 454-1315. Or write Microsoft Consumer Products, 10800 Northeast Eighth, Suite 819, Bellevue, WA 98004.

TRS-80 is a trademark of Radio Shack Corp. "Appie II is a trademark of Apple Computer, Inc.,'" Editor/Assembler-Plus and Z-Bug are trademarks of Microsoft. TRM js^ a trademark of The Image Producers, Inc.

Circle 111 on inquiry card.

BYTE February 1980 161

BYTE's Bits

Ken Bowles'

Current Activities:

Training in Pascal...

notes by C Helmers

In the last year or so, we have been placing much emphasis on the computer language Pascal, with particular attention to the University of California at San Diego (UCSD) system which, by being available, has become a de facto standard for small-computer, Pascal-oriented systems software. Dr Kenneth Bowles of UCSD was the originator of the project which generated the UCSD system, and he is its prime mover.

As a professor of Computer Science and Electrical Engineering at UCSD, Dr Bowles has been instrumental in the implementation of Pascal on small computers, starting with the LSI11-based Terak machine, and now including all the major 8-bit microprocessor designs. Since its inception in 1974, UCSD Pascal has been licensed to more than 1000 individuals and organizations. With the recent availability on the Apple II, North Star Horizon, and other major personal computer systems, the UCSD software has become a major, machineindependent, industry-wide standard for an operating system and compiler. Due to the nonprofit status of the University of California, the system has been recently spun off to an independent software company, Softech Micro Systems of San Diego, California.

Dr Bowles' purposes in developing the UCSD Pascal system included the desire to make widely available a convenient and machineindependent structured programming language and operating system. The non

Photo 1: The hands-on aspect of Ken's Integrated Computer Systems continuing education course on Pascal is provided by use of a number of portable computers such as the Apple II Pascal system. Ken is shown here demonstrating a point to some students.

commercial intellectual success of the Bell Laboratories UNIX operating system, with its language C, was doubtlessly an inspiration for the UCSD concept of a machine-independent operating system and language. As a teaching device in schools and universities, the intellectual popularity of the Pascal language was part of the reason for choosing it as a suitable vehicle for widespread teaching of programming concepts and convenient application programming. Also key to the choice of Pascal as a language to

pursue was the fact that its originators, Niklaus Wirth and Kathleen Jensen, had designed a concise but robust high-level language which was first (and most typically) implemented through the highly machineindependent technique of simulating a virtual "P-machine" on conventional machines. The rest is history. An operating system with many interactive features, editors and file management programs was written in Pascal along with the compiler; the code was made available and when the response got too large

for the university's "nonprofit" political environment, the system's marketing and maintenance operations were assigned to a commercial company.

Ken is now participating in the continuing education programs of a company called Integrated Computer Systems Inc. This company specializes in intensive training courses given in major cities, as a sort of traveling road show intended for potential users of hightechnology tools such as the Pascal language. Ken's course is designed for engineers, scientists and programmer/analysts who plan to use Pascal for the development of software systems. The class features exercises involving text processing, interactive data collection, dynamic graphic display and real-time control applications. Class sizes are strictly limited to (typically) 36 students in order to provide maximum hands-on activity.

The course is operated for four days (Tuesday thru Friday). Each attendee receives a diploma and one Continuing Education Unit for each 10 hours of participation. The Continuing Education Unit is a nationally recognized credit awarded by universities and educational organizations for participation in such programs. (Scheduled time each day of the four-day schedule is from 9 AM to 6 PM, so in principle one could obtain 3.6 such units from the course given attendance of the full four-day schedule.) The price is $795 including all materials, luncheons and coffee breaks. The following dates are presently scheduled:

San Francisco CA: February 12-15, 1980

162 February 1980 © BYTE Publications Inc

PUTTING IT ALL TOGETHER

Four-User North Star Horizon with 29 Megabyte Hard Disk Interface

inCLUDIHO:

48K RAM per user

Two 360K 5'A" disk drives (as many as four, optional)

Two printers: One Texas Instruments TI 810 dot matrix, 150 character per second, bi-directional, tractor feed printer with all available options One NEC Spinwriter 5510 document quality, full-character printer with friction feed and tractor feed

Deluxe printer stands and paper trays for both printers

One Discus 29 megabyte (26 megabyte formatted) Winchester technology, fixed hard disk unit with controller, cabinet, power supply, all cables, ports and connectors, completely interfaced to DOS and BASIC, CP/M, PASCAL and Micro Mike's interrupt-driven, bank-switching timesharing (as many as four 29 megabyte hard disk units, seven users, optional)

One custom computer/hard disk desk, Executive model, three CRT stands, thirty 5'A'' diskettes

"Micro Mike's, Incorporated Program Library Membership, including:

General Ledger

Accounts Receivable

Accounts Payable

Inventory

CSUB (Common SUBroutines)

Payroll

Mail list

Word Processing/Text Editing

Project Cattle Profits

Timesharing

DOSCHQ (eight inch drive interface to DOS and BASIC)

Commodities Charts

and many outstanding utilities programs and public domain software •All programs available separately. Total System $23,719

Micro Mike's, Inc. thoroughly "burns in" and tests all systems delivered as integrated hardware/ software systems, under timesharing conditions, the ultimate test of a complete computer system. This "burning-in" and testing procedure continues, non-stop, for a minimum of three days and nights, insuring the end user the highest quality, trouble-free integrated hardware/software system possible.

Micro Mike's, Inc. will, for a fee, deliver and set up a system anywhere in the USA. Personal user training and/or custom programming is also available.

Complete north Star

Horizon Service Center

Call or write for

descriptive literature

*****••*

Discus 29 megabyte Winchester technology fixed, sealed hard disk units completely interfaced to DOS and BASIC, CP/M and PASCAL for most S-100 buss computer systems, ready to go, including controller, cabinet and power supply, all cables, ports and connectors $5,495

Additional 29 megabyte drive, cabinet and power supply $4,495

********

Micro Mike's, Inc. offers a complete selection of top-notch business software. Among comprehensive programs are:

• Time and Expense package for accountants, attorneys, and other professionals • Patient Daily Record Program (Doctor/Patient Ledger) for Physicians • Land Subdivision package • Pharmacy • Motel Reservation with Night Audit • Banker's Trust • Feedlot • Oil/Qas Producer's package • many more

********

IN STOCK:

North Star Horizons

Discus double density or quad capacity eight inch drives for S-100 buss systems

Printers: Texas Instruments TI 810, NEC Spinwriter, IDS-440 Paper Tiger

Armadillo Armor 5'/4" protective

diskette shipping cartons .... $45

per hundred

Used Intertec Intertube CRTs, as-is condition, close-out $495

JlUkh

68

MICRO MIKE'S, INCORPORATED

905 South Buchanan Amarillo, Texas 79101 U.S.A. 806-372-3633

making technology uncomplicated. . . for People

Circle 112 on inquiry card.

BYTE February 1980 163

Circle 113 on inquiry card.

FOR YOU YOUR WIFE YOUR CHILD YOUR HOME YOUR SCHOOL YOUR BUSINESS

[A Computer System Both Practical and Affordable!

: Many uses for your computer, ■ Word ^Processing ■ Accounting ■ Bookkeeping! i Games ■ Personal Records ■ Menul iPlanning ■ EducationalDevelopment ■ Tax Preparation ■ Homework, etc.

BYTE SHOP EAST offers a wide selection of hardware to meet your specific needs; SORCERER, PET, APPLE, NORTH STAR, IMSAI, DIGITAL, and many, many others.BYTE SHOP EASThas |

a complete library of books and magazines to meet your needs.

Come in to our computer stores for a FREE demonstration!

BVTE SHOP EflSTJ

130 East 40th St. (Corner of Lexington Ave.) New York 10016" Tues.-Fri. 10- 6 Sat. 10- 5 (212) 889-4204

2721 Hempstead Turnpike (Just East of Wantagh Pkwy) Levittown, N.Y. 11756 Tues.-Fri. 12 - 8 Sat. 10 - 5 (516) 731-8116

New Robotype

Turns your typewriter

into a quality i output printer!

• easily connects to any computer

• serial and parallel interface

• all electronics included—ready to use from package

• connects to IBM Selectric TJ typewriter in just one minute

• adapts to a variety of typewriters—no modifications

• compatible with Radio Shack TRS-80, Apple II, Pet, etc.

• Centronics interface compatible

• available from stock in 30 days

Put a Robotype to work on your typewriter for under

$1,000. Call (614) 436-3163 today!

Dealer, distributors, and word processor OEM inquiries welcome.

£v Robotype

TM

(A trademark of Compu-Matics, Inc.)

Applied Computer Systems, Inc.

77 East Wilson Bridge Road • Worthington, Ohio 43085

Washington DC: March 4-7, 1980

Los Angeles CA: March 11-14, 1980

Atlanta GA:

March 18-21, 1980

Houston TX:

April 15-18, 1980

Boston MA:

April 29-May 2, 1980

San Diego CA: May 6-9, 1980

For further information and enrollment forms, contact Integrated Computer Systems Inc, 3304 Pico Blvd, Santa Monica CA 90405, or phone (213) 450-2060.

Call for Papers— 1980 LISP Conference

A call for papers has been announced for the August 24 thru August 27 LISP Conference at Stanford University. The topics should cover languages and theory, programming aspects, architecture, and applications of LISP. Other related items are welcome. Authors are requested to send four copies of a full draft paper not exceeding 4500 words, and a one-page abstract, by March 14, 1980 to the Conference Head. The abstract should provide sufficient detail to allow the committee to apply uniform criteria for acceptance. Authors will be notified of acceptance or rejection by May 16, 1980. For inclusion in the proceedings, final papers are due by June 27, 1980. Send papers to John R Allen, Stanford Artificial Intelligence Lab, Stanford University, Stanford CA 94305, or phone (415) 497-4971 for further details.

Bulletin Board Notes

A computerized bulletin board system (CBBS) is now in operation in Cambridge Massachusetts, thanks to the diligent labors of David Mitton and other members of

the New England Computer Society. Running the CBBS code written by Ward Christensen and Randy Suess on a Processor Technology Sol-20, the system is available around the clock. Two data rates are supported, 110 and 300 bits per second (bps). The telephone number to access the system is (617) 864-3819.

A description of a CBBS appeared in the article "Hobbyist Computerized Bulletin Board," by Christensen and Suess, in the November 1978 BYTE, page 150.

Call a Computer for Computers

If you want to purchase computer equipment, software, terminals, supplies, or any other related equipment, call (813) 885-4811 and talk to a computer. There is no charge but calls are limited to 3 minutes; however, if necessary, you can call again. There should be a listing of the items needed. To access the system: set your terminal for 300 bps operation, set the modem for full duplex originate operation, call (813) 885-4811, after the terminal is on-line enter any character and a carriage return. The system will respond "PLEASE LOG IN", then enter the string "HELLO-Z999," (only the characters underlined), then follow the directions on the terminal to search the file.

To place a listing with the service, contact Basic Online Software Systems Corp, POB 22412, Tampa FL 33622.

Cafeteria Chain Pioneers Computerized Cost Control of Recipes

A chain of cafeterias serving the Los Angeles public has developed a restaurant menu-planning system to minimize the effects of rapid inflation and skittish agricultural commodity prices.

164 February 1980 © BYTE Publications Inc

Circle 114 on inquiry card.

Model DMB-6400 Series dynamic 64k byte RAMS incorporate the features which are standard in the DM-6400 Series and adds bank select for multi-user-timesharins applications.

• Four (4) 16k byte, functionally independent memory banks.

• Eight (8) 64k byte banks of mem

• ALPHA MICRO, CROMEMCO, and NORTH STAR output port bank select.

• Memory bank size can be incremented to 64k bytes in 16k increments.

ory per output port for ex pan sion to 512k bytes for each output port.

Model DM-6400 Series dynamic 64k memory boards feature IEEE S-100 compatible timing and on board transparent refresh.

• Memory selectable and deselec- • 25 MHz on board crystal oscillator

table in 4k byte increments. for independent timing.

DMB-6400 and DM-6400 Common Features:

• 4 MHz Z80 operation with no wait states.

• Tested and bumed-in.

ONE YEAR GUARANTEE

• Low power- 8 watts maximum.

• Reliable, expandable memories.

THE FOLLOWING PRODUCTS ARE AVAILABLE □ DMB-3200/32KRAM

□ DMB-6400/64KRAM □ DMB-3200/32K RAM □ DM-6400/64K RAM

□ DMB-4800/48KRAM □ DM-4800/48K RAM

ATTRACTIVELY DISCOUNTED OEM AND DEALER QUANTITY PRICES AVAILABLE

D DM-3200/32KRAM

U.K. & EUROPEAN REPRESENTATIVE:

ABACUS COMPUTERS LTD. 62, NEW CAVENDISH STREET LONDON. W1M 7LD U.K. TEL: 01-580/8841 TELEX: 881-3085

AUSTRALIAN REPRESENTATIVE:

COMPUTERLAND OF MELBOURNE 555 COLLINS STREET MELBOURNE, VIC3000 TEL: 625581

MEASUREMENT

systems &. controls

incorporated

867 North Main Street • Orange, CA 92668 Telephone: 714/633-4460

Circle 115 on inquiry card.

BYTE February 1980 165

The menu planners at Clifton's Cafeterias enter current commodity pricing information into a Data General Corp computer system, and obtain the exact cost for each of 2500 recipes possible on Clifton's menus.

The CS/40 system has reduced the menu recost time from 9 months to 6 hours and could save the cafeteria chain about $50,000 annually. In addition to the food purchasing and recipe maintenance, the system can handle the

payroll for 600 employees and do accounts payable, a general ledger and a cash journal. The system includes a printer, four video terminals, a magnetic tape drive and a potential 250 K bytes of memory storage on the disk drives.

The CS/40 business system has reduced errors, provided current information, and has allowed for more interesting and more varied menus.

Contact the P R Dept, Data General Corp, Rt 9,

Westboro MA 01581, for more information.

Chicago Library Offers

Public Computers and a

Computerized Reference

Service

To permit the public to experience computer-assisted instruction (CAI), to perform basic computer routines and to gain experience in programming, microcomputers have been installed in the Business/

YOU THINK YOU'VE SEEN WORD PROCESSING SOFTWARE?

The

magic wand;

Word Processing

System offers you the best features of any system in the micro market

FEATURES INCLUDE: Full-screen text editor

Simple, control key operation Edit programs as well as text

Assemble, compile or run programs

without modification Files larger than memory

Files up to 256K Library files

Merge part or all of one file with

another Spool printing

Print a file while editing another Easy page formatting

Simple commands set margins, page

length, etc. Override commands at run-time

Give any command from the keyboard as well as in file Variable pitch control

Change pitch in mid-line, even

mid-word Up to 128 user-defined variables

String, numeric or dollar format Form letter generation from external data files

Compatible with both sequential and

fixed-record files Conditional commands

Any command may be conditional Print to disk and/or printer

Save all or part of output on disk Switch from specialty printer to CP/M list device

Print the same file on either specialty

or standard printer

EASE OF OPERATION

With all its power, the MAGIC WAND is remarkably easy to use. This is no accident. The command structure is designed to be flexible and logical so that you can perform basic functions with a minimum of commands.

We have included in the manual a stepby-step instructional program, for the person who has never used a word-processor before. The trainee uses sample files from the system disk and compares his work to simulated screens and printouts.

In addition to the lessons, the manual has a complete documentation of the command structure, special notes for programmers, an introduction to CP/M for non-programmers and a glossary. The manual is typeset, rather than typewritten, for greater legibility.

We have written the manual in nontechnical English, because we want you to read it. We don't overload you with a bunch of jargon that could confuse even a PhD in Computer Sciences.

We send out newsletters so that users of the MAGIC WAND can learn special applications of the print commands. For example, we might show you how to create a mailing list or set up an index for a file.

In short, we've done everything we can to make things easy for you. Because the best software in the world is just a bunch of code if you can't use it.

For more information, call or write:

srcuxW business ap^icaXious, u*.c.

3220 Louisiana • Suite 205 • Houston, Texas 77006 • 713-528-5158

Science/Technology Division of the Central Library, the Popular Library in the Cultural Center, the Woodson Regional Library, and the Lincoln Park Branch, all agencies of the Chicago Public Library.

The system includes video displays, software, training manuals, but no printers. It runs on BASIC, and has 8 K bytes of programmable memory. Engineers, businessmen, students developing chess skills, and people balancing their checkbooks have been using the devices. If usage increases substantially, the Library will consider the purchase of additional units for other branches in the library system.

Their other service provides millions of references to books, periodicals, reports, all on a wide range of subjects. Where manual research can take hours or even days, the computerized service can reduce to only a few minutes the time usually required for a thorough research study. For this service, the first 5 minutes of computer time are free and each additional minute costs $1.50. Contact the Business/Science/Technology Division in the Central Library at 425 N Michigan Ave, Chicago IL 60611, or call (312) 269-2915.

Apple Education

Foundation Advances

Learning Methods

Through Microcomputers

Initially funded by Apple Computer, the nonprofit foundation will offer support and resources to organizations and individuals who are pioneering learning methods through the use of microcomputers. Funding authorizations through 1980 are valued in excess of $250,000. The foundation will distribute hardware equipment for both developmental and demonstration projects involved in producing instructional computing materials. The foundation's primary

166 February 1980 © BYTE Publications Inc

Circle 116 on inquiry card.

after

BATTERY SUPPORTED CALENDAR CLOCKS

PDP-11*

TCU-100*$495

■ Provides month, day, hour, minute and second.

■ Can interrupt on date/time, or periodic intervals.

TCU-150-$460

■ Provides year, month, day, hour, minute and second.

■ Automatic leap year.

■ Patches for RSX-11M, RT-11 FB/SJ V02, V03 and UNIX.

LSI-11/2*

TCU-50D • $325

■ Provides month, day, hour, minute and second.

■ Dual size board.

■ Patches for RT-11 SJ/FB V02, V03B.

Lockheed SUE

TCU-200 • $550

■ Provides year, month, day, hour, minute, second and milli-second.

■ Interval interrupts between 1/1024 seconds and 64 seconds.

Computer Automation (Naked Mini)

TCU-310-$385

■ Provides year, month, day, hour, minute and second.

'Trademark of Digital Equipment Corporation

Multi-Bus**

TCU-410*$325

■ Provides year, month, day, hour, minute and second.

■ SBC/BLC compatible.

HP 2100

TCU-2100*$395

■ Correct time restored after power failure.

■ Compatible with the HP TBG card.

Serial Clock (RS 232 or 20 mA)

SLC-1 • $640

■ Connects between any terminal and host computer.

■ Provides date, time and more!

All Digital Pathways TCUs have on board NICAD batteries to maintain time and date during power down. Timing is provided by a crystal controlled oscillator. Prices are U.S. domestic single piece. Quantity discounts available.

For more information on these products, contact: Digital Pathways Inc. 4151 Middlefield Road Palo Alto, CA 94306 Phone: (415) 493-5544

* 'Trademark of Intel Corporation ** "Trademark of Computer Automation Incorporated

DIGITAL PATHWAYS

Circle 117 on inquiry card.

BYTE February 1980 167

Circle 118 on inquiry card.

Kill Surges Like Lightning!

Surge Sentry 120 works in parallel with the power line to shunt destructive power surges in less than 1 nanosecond! Triggers at 10% above the nominal peak voltage. Plugs into any standard 120-volt outlet for immediate protection.

Ideal for small computers, communications, medical, and other sensitive electronic equipment. Suggested retail price $89.50. OEM model also available. Call or write:

l] [< Z R&K Enterprises

643 South 6th Street, San Jose, CA 95112 (408) 288-5565.

Dealer inquiries invited.

DECLSMl Components

Dependable service at discount prices

Domestic WSjO }

and Export

p

A A

„

t

■

" ■

/v vv L

mini

Computer Suppliers,Inc.

25 Chatham Rd., Summit, N.J. 07901 Since 1973

(201) 277-6150 Telex 13-6476

©Mini Computer Suppliers, Inc. 1979

goal is to place hardware into the hands of people who will further those educational methods that best take advantage of the personal microcomputer's capabilities.

As continuing evidence of its commitment to education, the foundation will sponsor the Education Program Information Center (EPIC). EPIC will support microcomputer users in developing new instructional programs and in obtaining available information on educational materials. Authors are encouraged to submit their work to the center for review and feedback on the most effective uses and placements of their materials.

Both the Apple Education Foundation and EPIC may be contacted through the Apple Education Foundation, 20605 Lazaneo Dr, Cupertino CA 95014.

AIDs for Apple Dealers

AIDs (Apple Independent Dealers) was formed by and for independent Apple dealers, ie: those dealers with no direct contractual agreement or connection with any national chain or franchise. AIDs will provide a framework for improved communication, education, and support to its members, which will also be of benefit to consumers. This will include sharing of information on new software and hardware evaluations, successful marketing and problem solving, advertising ideas and more.

Full membership for qualified dealers is $35 per year. For more information, contact Harry Sweeney, (503) 228-5242 or send a self-addressed, stamped envelope to AIDs, POB 06126, Portland OR 97206.

Report Studies Threat to

Auto Electronics from

Electric Fields

With the increased use of electronic control systems in automobiles, there is con

cern about possible malfunction or deterioration of function due to ambient electrical fields created by radio and television transmitters, high-powered radar, power transmission lines, or lightning strokes.

Researchers at the National Telecommunications and Information Administration (NTIA) have surveyed sources emanating energy across the radio-frequency portion of the electromagnetic spectrum. Their report indicates that vehicles might sometimes — although rarely — be exposed to radio-frequency fields of 5 kV per meter which may cause the vehicle to become inoperative or may even damage its electronics.

The report is available from the National Technical Information Service, 5285 Port Royal Rd, Springfield VA 22161 for $4.50. The accession number is PB 294-819/AS. For further information, contact NTIA Office of Congressional and Public Affairs (202) 377-1832. ■

BYTE's Bugs

Correct Reversi Termination

I would like to point out a programming error in "Reversi," which was published in the November 1979 BYTE, on page 76. The problem with the program is that it recognizes the end-ofgame criterion too early, allowing the occurrence of a player not having a move only twice throughout the length of the game. This is due to the fact that countervariable T3 is never reinitialized when a player is able to move. I recommend insertion of the following code: 296 LET T3 = 0.

Darrell Pittman

4225 Forest Dr

Port Arthur TX 77640 ■

168 February i960 © BYTE Publications Inc Circle 119 on inquiry card.

By Netronics

ASCII/BAUDOT, STAND ALONE

COMPLETE FOR ONLY .

Computer $1AQ Terminal 1W

95

The Netronics ASCII/BAUDOT Computer Terminal Kit is a microprocessor-controlled, stand alone keyboard/terminal requring no computer memory or software. It allows the use of either a 64. or 32 character by 16 line professional display format with selectable baud rate, RS232-C or 20 ma. output, full cursor control and 75 ohm composite video output.

The keyboard follows the standard typewriter configuration and generates the entire 128 character ASCII upper/lower case set with 96 printable characters. Features include onboard regulators, selectable parity, shift lock key, alpha lock jumper, a drive capability of one TTY load, and the ability to mate directly with almost any computer, including the new Explorer/85 and ELF products by Netronics.

The Computer Terminal requires no I/O mapping and includes Ik of memory, character generator, 2 key rollover, processor controlled cursor control, parallel ASCII/BAUDOT to serial conversion and serial to video processing—fully crystal controlled for superb accuracy. PC boards are the highest quality glass cpoxy for the ultimate in reliability and long life.

VIDEO DISPLAY SPECIFICATIONS

The heart of the Netronics Computer Terminal is the microprocessor-controlled Netronics Video Display Board (VID) which allows the terminal to utilize either a parallel ASCII or BAUDOT signal source. The VID converts the parallel data to serial data which is then formatted to either RS232-C or 20 ma. current loop output, which can be connected to the serial I/O on your computer or other interface, i.e., Modem.

When connected to a computer, the computer must echo the character received. This data is received by the VID which processes the information, converting to data to video suitable to be displayed on a TV se't (using an RF modulator) or on a video monitor. The VID generates the cursor, horizontal and vertical sync pulses and performs the housekeeping relative to which 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: 110 and300 ASCII • Outputs: RS232-Cor20 ma. current loop • ASCII Character Sel: 128 printable characters—

!,mi,()*+,-./0123456789: ;<*>?

WeCOffGHIJKLrlCPQRSTUUyXVZCvr. v&C<Jef9hiiklfM0MrstUUM<iZ{i>*l

BAUDOT Character Set: ABCDEFGHIJKLMNOPQ RSTUVWXYZ-?:*3$ti().,90I4!57;2/68» Cursor Modes: Home, Backspace, Horizontal Tab, Line Feed, Vertical Tab, Carriage Return. Two special cursor sequences are provided for absolute and relative X- Y cursor addressing • Cursor Control: Erase, End of Line, Erase of Screen, Form Feed, Delete • Monitor Operation: 50 or 60Hz (jumper selectable.

Continental U.S.A. Credit Card Buyers Outside Connecticut

CALL TOLL FREE 800-243-7428

To Order From Connecticut Or For Technical _— ^ T* Assistance, Etc. Call (203) 354-9375

I Netronics R&D Ltd., Dept. PE-9 333 Litchfield Road, New Milford, CT 06776

| Please send the items checked below—

ID Netronics Stand Alone ASCII Keyboard/Computer Terminal Kit, $149.95 plus $3.00 postage & handling. ID Deluxe Steel Cabinet for Netronics Keyboard/Terminal In Blue/Black Finish, $19.95 plus $2.50 postage I and handling. □ Video Display Board Kit alone (less keyboard), $89.95

I plus $3 postage & handling. □ 12" Video Monitor (10 MHz bandwidth) fully assemIbled 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 Cabinet (±8VDC @ 5 amps, plus 6-8 VAC), $39.95 plus $2 postage & handling.

I Total Enclosed (Conn. res. add sales tax) $ By

ID Personal Check □ Cashiers Check/Money Order □ Visa □ Master Charge (Bank ft )

I Acct. tt . .

_ Signature

I Print

_Exp. Date .

Name _

City.

u_

_Zip

D Send Me More Information

-_J

Start Computing For Just $129.95 With An 8085-Based Professional Computer Kit—

Explorer/85

700% compatible with all 8080A and 8085 software & development tools!

No matter what your future computing plans may be, 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/85 can be your beginner's system, OEM controller, or IBMformatted 8" disk small business system. . .yet you're never forced to spend a penny for a component or feature you don V want and you can expand in small, affordable steps!

Now, for just $129.95, you can own the first level of a fully expandable computer with professional capabilities—a computer which features the advanced Intel 8085 cpu, thereby giving you immediate access to all software and development tools that exist for both the 8085 and its 8080A predecessor (they are 100% software compatible)—a computer which features onboard S-100 bus expansion—plus instant conversion to mass storage disk memory with either 5-1/4" diskettes or 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 magazines. . .developing "state of the art" computer solutions for both the industrial and leisure environment.

Level "A" Specifications

Explorer/85's Level "A" system features the advanced Intel 8085 cpu, an 8355 ROM with 2k deluxe monitor/operating system, and an 8155 ROM-I/O—all on a single motherboard with room for RAM/ROM/PROM/EPROM and S-100 expansion, plus generous prototyping space.

(Level "A" makes a perfect OEM controller for industrial applications and is available in a special Hex Version which can be programmed using the Netronics Hex Keypad/ Display.)

PC Board: glass epoxy, plated through holes with solder mask • I/O: provisions for 25-pin (DB25) connector for terminal serial I/O, which can also support a paper tape reader ... provision for 24-pin DIP socket for hex keyboard/display .., cassette tape recorder input.. .cassette tape recorder output.. .cassette tape control output.. .speaker output... LED output indicator on SOD (serial output) line.. .printer interface (less drivers).. .total of four 8-bit plus one 6-bit I/O ports •Crystal Frequency: 6.144 MHz • Control Switches: reset and user (RST 7.5) interrupt.. .additional provisions for RST 5.5, 6.5 and TRAP interrupts onboard • Counter/Timer: programmable, 14-bit binary • System RAM: 256 bytes located at F800, ideal for smaller systems and for use as an isolated stack area in expanded systems.. .RAM expandable to 64k via S-100 bus or 4K on motherboard.

System Monitor (Terminal Version): 2k bytes of deluxe system monitor ROM located at F000 leaving 0000 free for user RAM/ROM. Features include tape load with labeling ...tape dump with labeling.. .examine/change contents of memory .. .insert data.. .warm start.. .examine and change all registers.. .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.. .fill blocks of memory with a constant... display blocks of memory .. .automatic baud rate selection .. variable display line length control (1-255 characters/line). . .channelized I/O monitor routine with 8-bit parallel output for high speed printer... serial console in and console out channel so that monitor can communicate with I/O ports.

System Monitor (Hex Version): Tape load with labeling... tape dump with labeling... examine/change contents of memory...insert data...warm start.. .examine and change all

By Netronics

Level "A" at $129.95 is a complete operating system, perfect for beginners, hobbiests, or industrial controller use.

Hex Keypad/Display.

Explorer/85 with "C"cardcage.

r&ducT, fipTHEnff"

eld Road. New Milford, C"

Netronics 333 Litchfield

Please send the items checked below— D Explorer/85 Level "A" Kit (ASCII Version), $129.95 plus $3 p&h.

□ Explorer/85 Level "A" Kit (Hex Version), $129.95 plus $3 p&h.

D 8k Microsoft BASIC on cassette tape, $64.95 postpaid. D 8k Microsoft BASIC in ROM Kit (requires Levels "B," "D," and "E"), $99.95 plus $2 p&h.

□ 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, $69.95

plus $2 p&h.

D Level "E" (EPROM/ROM) Kit,

$5.95 plus 50<r p&h.

□ Deluxe Steel Cabinet for Explorer/ 85, $49.95 plus $3 p&h.

□ ASCII Keyboard/Computer Terminal Kit (features a full 128 character set, upper & lower case, full cursor control, 75 ohm video output convertible to baudot output, selectable baud rate, RS232-C or 20 ma. I/O, 32 or 64 character by 16 line formats, and can be used with either a CRT monitor or a TV set (if you have an RF modulator), $149.95 plus $2.50 p&h.

CT 06676

plus$2p&!i.

D Deluxe Steel Cabinet for ASCII

Keyboard/Terminal, $19.95 plus $2.50

p&h.

□ Power Supply Kit (± 8V @ 5 amps) in deluxe steel cabinet, $39.95 plus $2 p&h.

□ Gold Plated S-100 Bus Connectors, $4.85 each, postpaid. D RF Modulator Kit (allows you to use your TV sel as a monitor), $8.95 postpaid.

D 16k RAM Kit (S-i 00 Board expands to 64k), $199.95 plus $2 p&h. D 32k RAM Kit, $329.95 plus $2 p&h.

□ 48K RAM Kit, $459.95 plus $2 p&h. D 64kRAMKitr$589.95plus$2p&h. D 16k RAM Expansion Kit (to expand any of the above up to 64k), $139.95 plus $2 p&h each.

D Intel 8085 cpu User's Manual, $7.50 postpaid.

D Special Computer Grade Cassette Tapes, $1.90 each or 3 for $5, postpaid. D 12" Video Monitor (10 MHz bandwidth), $139.95 plus $5 p&h.

□ North Star Double Density Floppy Disk Kit (One Drive) for Explorer/ 85 (includes 3 drive S-100 controller.

registers.. .single step with register display at each break point ...go to execution address. Level "A" in the Hex Version makes a perfect controller for industrial applications and can be programmed using the Netronics Hex Keypad/Display.

p- Hex Keypad/Display Specifications

Calculator type keypad with 24 system defined and 16 user defined keys. 6 digit calculator type display which displays full address plus data as well as register and status information. Level "B" Specifications

LeveI"B" provides the S-100 signals plus buffers/drivers to support up to six S-100 bus boards and includes: address decoding for onboard 4k RAM expansion select-able in 4kblocks.. .address decoding for onboard 8k EPROM expansion selectable in 8k blocks.. .address and data bus drivers for onboard expansion.. .wait state generator (jumper selectable), to allow the use of slower memories. . .two separate 5 volt regulators.

Level "C" Specifications

Level "C" expands Explorer's motherboard with a card cage, allowing you to plug up to six S-100 cards directly into the motherboard. Both cage and « cards are neatly contained inside Explorer's deluxe steel cabinet. Level "C" includes a sheet metal superstructure, a 5-card gold plated S-100 extension PC board which plugs into the motherboard. 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 your Explorer/85 memory to 4k (plus the original 256 bytes located in the 8155A). The static RAM can be located anywhere from 0000 to EFFF in 4k blocks.

Level "E" Specifications

Level "E" adds sockets for 8k of EPROM to use the popular Intel 2716 or the Tl 2516. It includes all sockets, power supply regulator, heat sink, filtering and decoupling components. Sockets may also be used for soon to be available RAM IC's (allowing for up to I2k of onboard RAM).

Order A Coordinated Explorer/85 Applications Pak!

Experimenter's Pak (SAVE $12.50)—Buy Level "A" and Hex Keypad/Display for $199.90 and get FREE Intel 8085 user's manual plus FREE postage & handling!

Student Pak (SAVE $24.45)-Buy Level "A," ASCII Keyboard/Computer Terminal, and Power Supply for $319.85 and get FREE RF Modulator plus FREE Intel 8085 user's manual plus 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 $514.75 and get 10 FREE computer grade cassette tapes plus FREE 8085 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 Keyboard/Computer Terminal (with cabinet), 16k RAM, 12" Video Monitor, North Star 5-1/4" Disk Drive (includes North Star 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 |

sonalized disk operating system—just« plug it in and you're up and running!), I $699.95 plus $5 p&h.

□ Power Supply Kit for North Starl Disk Drive, $39.95 plus $2 p&h.

□ Deluxe Case for North Star Disk! Drive, $39.95 plus $2 p&h. D Experimenter's Pak (see above), I $199.90 postpaid.

D Student Pak (see above), S319.8s| postpaid.

D Engineering Pak (see above), I $514.75 postpaid.

D Business Pak (see above), $1599.401 postpaid.

Total Enclosed $ I

(Conn. res. add sales tax) By— |

D Personal Check D M.O./Cashier's I Check □ Visa □ Master Charge |

(Bank#_

Signature _ Print

Name

_Exp. Date _

\

City.

Circle 120 on inquiry card.

I

| D Hex Keypad/Display Kit, $69.95 DOS. and extended BASIC with per- State

Circle 300 on inquiry card.

_Zip_

D Send Me Information

^J

BYTE February 1980 169

DISK EXPANSION PACKAGE

This package includes everything necessary to add disk capabilities to your TRS-80. To buy everything in this package would normally cost $1100 at your local Radio Shack store. We start with the Radio Shack expansion interface and add 16K RAM. You also receive a Percom 40-track disk drive with a dual drive cable. To start you off right, we've added the NEWDOS (40-track) disk operating system and a box of BASF diskettes. Also, the Percom data separator, the component which Radio Shack forgot. SAVE $181.00

6 South Street ■ Milford, New Hampshire 03055-(603) 673-5144

SMALL BUSINESS PACKAGE

An ideal starter package for the small business. Includes a TRS-80 with 16K RAM and Level II BASIC, an expansion interface with an additional 16K RAM installed, two Percom disk drives-with cable and data separator, NEWDOS disk operating system (40 track version) and the Centronics 730 line printer. 159700 0^ SAVE $579.00 '

$899.95

DELUXE EXPANSION PACKAGE

This package includes a 32K expansion interface with the Percom data separator installed, two Percom TFD-100 disk drives and a 4-drive cable, NEWDOS+ operating system and 2 boxes of BASF diskettes. $1449 95

SAVE $354.00

TOLL-FREE

ORDER

1-800-258-1790

LIST

OUR

USED

USED

TRS-80 COMPUTERS:

PRICE

PRICE

OFFER

PRICE

Level-I 4K

$499

$449

Level-I 16K, w/keypad

$729

$659

Level-ll 4K

$619

$559

$350

$500

Level-I I 16K

$669

$450

$625

Level-ll 16K, w/keypad

$849

$769

$475

$675

PRINTERS:

Line Printer III

$1999

$1849

Centronics 779-2

$1598

$1095

$655

$850

Line Printer II

$999

$545

$750

Centronics 730

$999

$899

$545

$750

Centronics P1 *

$499

$419

$250

$358

Quick Printer II

$219

$197

$100

$150

QP-II Exp. Int. Cable

$20

$18

* Cable required

$39

$35

«

^^ * 5|c COD orders require •OC^ 25% cash deposit

^Pv ^Prices subject to change ^CPrices do not include shipping

DELUXE BUSINESS PACKAGE

Includes all the necessities for a small-to-medium size business to become computerized. Includes a Level II TRS-80 with 16K RAM installed and modified to display upper and lower case letters with Electric Pencil, a 32K RAM expansion interface with the Percom data separator installed,three Percom TFD-10 disk drives and a 4-drive cable, a Centronics 779-2 tractor feed printer, a 40-track NEWDOS and Electric Pencil Word Processor software. We have even added a system desk and printer stand. "t^TOQ Q<>

SAVE $628.00

MHKUol.^^—, L|ST 0UR

EXPANSION INTERFACE: PRICE PRICE OFF

OK $299 $269

16K $448 379/403

32 K $597 479/537

DISK DRIVES:

Percom, TFD-100, 40-track Percom, dual TFD-100 Percom, TFD-200, 77-track 2-drive cable 4-drive cable

Radio Shack, Radio Shack,

0 1, 2,

ACCESSORIES:

Telephone Interface 16K Memory Kit 16K Memory Kit for E.I. RS232-C Interface TRS-232 Interface Data Dubber

$499 $399

$199 $99

$399 $795 $675 $29 $39 $469 $459

$179 $99 $95 $89 $49.95 $49.95

NO SUBSTITUTIONS ON PACKAGE PRICES 'Radio Shack and TRS-80 are trademarks of Tandy Corporation.

USED

USED

3FFER

PRICE

$165

$230

$245

$340

$325

$440

$290

$390

$270

$370

$100

$150

$55

$75

170 BYTE February 1980

Circle 227 on inquiry card.

CO

HI

CO

111

<

CO CO

HI

z

CO CD

NEW SOFTWARE!

Original ADVENTURE (Microsoft)

$29.95

Galactic Empire 16K L II $14.95

Alien Invasion 16K L II $ 9.95

Kriegspiei(wargame)16K L II. $7.95 Oil Baron 16KL II $7.95

Casino Anthology 16K L II $ 7.95

TRS-80 Opera Theatre $ 9.95

Print Spooler (Disk) $24.95

Floppy Disk Diagnostic (Disk)$24.95 File Manager 80 $49.95

COMPLETE IN FEBRUARY SOFTSIDE!

Simulation of flying the United States shuttle. The ultimate flight simulation! Based on actual flight characteristics and instrument display of the space shuttle.

File Manager 80 by Nepenthe. $49.95 32K Disk Directory 16K Disk $9.95

Automated Disk Directory $14.95 32K Disk. Requires NewDOS.

Level III BASIC by Microsoft. $49.95 Level I In Level II by Apparat. Level II, 16K $15.00 Fortran by Microsoft. 32K - 2 Disks. New low price $150.00 (includes macro-assembler.)

NEWDOS by Apparat $49.95

NEWDOS + by Apparat $99.95

Machine Language Monitor by Small Systems

Software. Level II, 16K $26.95

Renumber by Lance Micklus. Level II, available

in 16 through 48K (specify when ordering) $7.95

Renumber source listing $20.00

Three Monitors for Disk by Small Systems Software. Disk for 16 through 48K (all in one) $29.95 KVP Extender by Lance Micklus. Tape - $29.95; Disk - $34.95

KVP 232 by Lance Micklus - KVP adapted for the TRS-232. Tape - $29.95 STB0 Smart Terminal Level II, 16K $49.95 ST80D Smarter Terminal for disk systems. $79.95

Micro Text Editor by Don Coons. Level II, 4K or 16K $9.95

Text-80 by Frank B. Rowlett, Jr. For 32K disk systems $59.95

8080-Z80 Conversion Level II, 16K $14.95 STAD Trace Monitor 16, 32 and 48K $24.95

Electric Pencil by Michael Shrayer. Powerful machine language word processing system. Level II, 16K tape - $100; Disk version - $150

Spool will print an ASCII file to a parallel line printer at the same time you are using your computer for another program. For 32K Disk Systems only. Will NOT work with NEWDOS. (2.3 or VTOS 3.0 OK) On cassette $19.95, on Disk $24.95.

TRS-80 Opera Theatre Magnificent sound! by

Richard Taylor. $9.95

Challenge Word game with sound. By Richard

Taylor $9.95

Oil Baron by Paul Knechtel $7.95

Galactic Empire by Douglas Carlston $7.95

Casino Anthology Slot Machine, Stud and Draw

Poker. $7.95.

Alien Invasion $9.95

Concentration by Lance Micklus. Level II, 16K

$7.95

Amazin' Mazes by Robert Wallace. Level II, 16K

$7.95

Time Bomb by David Bohlke. Level II, 16K $4.95

Tycoon by David Bohlke. Level II, 16K $7.95

9 Games for Preschool Children by George

Blank. Level II, 16K $9.95

Space Battles by Level IV, Level II, 16K Tape or

32K Disk, Tape -$14.95, Disk - $19.95

Star Trek III.4 by Lance Micklus Level II, 16K

$14.95

Snake Eggs by Leo Christopherson. With sound

- Level II, 16K $14.95

Life Two by Leo Christopherson. With sound

-Level II, 16K $14.95

Android Nim by Leo Christopherson. With

sound - Level II, 16K $14.95

Cubes by Leo Christopherson Level II, 16K$9.95

Bee Wary by Leo Christopherson, with sound.

Level II, 16K, $14.95

Mastermind II by Lance Micklus $7.95

Mastermind II - Source List $20.00

XWing II by Chris Freund. Level II, 16K $9.95

Taipan by Art Canfil. Level II, 16K $9.95

Sargon Chess by Dan and Kathe Spracklen.

Level II, 16K $19.95

Sargon II by Dan and Kathe Spracklen. Level II,

16K. $29.95.

Pork Barrel by George Blank. Level II, 16K $9.95

Kamikaze by Russell Starkey. Level II, 16K $7.95

Bridge Challenger Level II, 16K, $14.95.

16K Level II tape $14.95 each

1,2,and3ondisk$39.95 4,5, and 6 on disk $39.95

Adventures by Scott Adams

Adventureland 2.Pirates Cove 3.Mission Impossible

4. Voodoo Castle

5. The Count

6. Strange Odessey

7. Fun House

8. Pyramid Of Doom

'Round the Horn by George Blank. Level II, 16K

$9.95

Barricade by Small Systems Software. Machine

Language $9.95

Journey To The Center Of The Earth by Greg

Hassett. Level II, 16KTape $7.95

Pentominoes by John Adamson. Level II, 16K

$7.95

Mean Checkers Machine by Lance Micklus.

Level II, 16K; tape, $19.95; disk $24.95.

Kriegspiel by Ron Potkin. Level II, 16K, $7.95.

Inventory System II.3 by M. Kelleher. Improved version, $79.95

Inventory 'S' by Roger W. Robitaille, Sr. Level II, 16K Tape -$24.95; 32K Disk -$39.95

Payroll by Stephen Hebbler. For disk systems. 32K $29.95

Accounts Receivable II by S. Hebbler. 32K disk

systems $39.95

Appointment Log by Michael Kelleher. Level II,

16K $9.95

Mail List II by Roger W. Robitaille, Sr. 32K disk

systems $99.95

Small Business Bookkeeping II by R. W.

Robitaille, Sr. Level II, 16K. With journal -$36.95 disk, $31.95 tape. $29.95 disk, $24.95 tape.

<co — o

luce co

co

O O m

Math Drill by K. L Brown. Level II, 16K $4.95

RPN Calculator by Russell Starkey. Level II, 16K

$9.95

Ham Radio by Michael Kelleher. Level II, 16K

$9.95

Histograph/Scattergram by Gary S. Breschini.

Level II, 16K $9.95

Sargon Handbook by Dan & Kathe Spracklen. $14.95 plus $1.00 shipping and handling The BASIC Handbook by Dr. David A. Lien. $14.95 plus $1

Z80 Instruction Handbook by Scelbi Publications $4.95 I $1.

Learning Level II by David A. Lien. $15.95 plus$1 Z-80 Software Gourmet Guide and Cookbook from Scelbi. $14.95 + $1.

The Little Book Of BASIC Style by John Nevison. $5.95 plus $1

TRS-80 Assembly Language Programming by William Barden, Jr. $3.95 plus $1 shipping Introduction to TRS-80 Graphics by Don Inman. $7.95 plus $1

Amateur Radio advanced version for 32K

disk $24.95

Electronics Assistant by John Adamson. Level

II, 16K $9.95

Preflight by Stephen Hebbler. Level II, 16K

$20.00

TO ORDER:

IMPORTANT:

• PRICES DO NOT INCLUDE SHIPPING.

• All C.O.D.'s or special delivery orders are a minimum of $5 for special handling.

• When ordering Percom add $5 each, packaging and handling fee.

• Prices subject to change without

notice. We are not typographical errors.

responsible

Basic Statistics by Steve Reisser. Level II, 16K $20.00

Drill Masters by Computer Graphics - specify title desired. Level II, 16K $7.95 ea. German, Russian, Italian, Spanish, or Music Theory. Keyboard by John Adamson. Level II, 16K $9.95

1-800-258-1790

CALL TOLL-FREE (9AM ■ 9PM EST.)

TRS-80 is a registered trademark Radio Shack and Tandy Corporation

Circle 121 on inquiry card.

BYTE February 1980 171

Technical Fwum

TRS-80 AUDIO METERING BOX

Audio Meter for Your TRS-80

David F Miller, 7462 Lawler Ave, Niles IL 60648

Perhaps I am old-fashioned, but I like to know what is happening when I CLOAD or CSAVE a tape on my TRS-80. I modified the CTR-41 cassette recorder to allow me to hear over its internal speaker what is going in and coming out at all times, but that did not tell me enough about the levels involved.

As you have probably discovered, audio levels in and out of the cassette port are very important for the successful loading and saving of your hard-fought-for efforts on tape. Interpolating the volume control settings of the cassette unit on playback can produce a degree of accuracy, but not for tapes received from others. The only sure way to understand what is going on is a visual indicator. The best device would be an oscilloscope, but I could not see dedicating my oscilloscope permanently to this type of duty.

The metering circuit shown in figure 1 has proven to be adequate for day-to-day monitoring and can be supplemented by the oscilloscope when a difficult tape is encountered. If you have an oscilloscope, look at the earphone output of the cassette recorder while playing back a tape. What you will see is a constant synchronization

Photo 1: A view of the audio metering box which connects to the Radio Shack TRS-80.

TO

TRS-80 COMPUTER AUDIO IN

J 1

1/8"

PHONE

JACK

(INLINE)

Dl

1N34

GERMANIUM

DIODE

v

FROM

CASSETTE

RECORDER

"EAR"

JACK

PI 1/8" PHONE PLUG

Rl 47.fl 1/2W —VSv—

-w

Cl 2.2^F

35V

■\t

Ml

0-lmA

METER

D2

1N34

GERMANIUM

DIODE

DETECTS NEGATIVE GOING PULSES FROM CASSETTE MACHINE

RADIO

SHACK NUMBER

CI 272-1407

Dl 8 D2 276- 1123

Jl a PI 274-283

Ml 22-052 OR EQUIVALENT

Rl 271-009

Figure 1: Schematic for the TRS-80 audio metering box. The 2 diodes used must be germanium diodes.

train of negative pulses occurring at a frequency of 500 Hz, with negative data pulses popping in and out at 1000 Hz. (These figures are for Level II. Level I figures are half, or 250 Hz and 500 Hz.)

The metering circuit shown in figure 1 samples these negative pulses, rectifies and filters them, and drives the 1 mA meter movement. With the values shown, the meter will read about half scale with the volume on the cassette unit set at 5 (normal setting for Level II tapes). To trim the meter reading for your individual needs, change the value of the electrolytic capacitor across the meter (more capacity for a higher reading); this will probably have the most noticeable effect. You could also increase or decrease the 47 ohm series resistor, but watch for possible "loading" effects if you go too low in value (the value shown shows no such effects). The diode across the meter acts to protect the movement when high levels are encountered (such as during a tape search in fast forward or rewind with the "play" button also engaged). Both diodes are specified as germanium because there is only 0.3 V barrier potential (ie, voltage drop) across a germanium type, whereas a silicon diode has 0.7 V drop.

The earphone jack on the CTR-41, and most other recorders, outputs the audio signal from the record amplifier when in the record mode, so you will see what is CLOADed and what is CSAVEed.

Photo 1 shows how my unit is packaged. I mounted a 1/8 inch phone jack on the rear of the plastic meter box which accepts the plug to the TRS-80. This jack should be insulated from the box if you use a metal enclosure, or

172 February 1980 © BYTE Publications Inc

{COMPUPRO1 CONTINUES TO 1 ■«mhi DELIVER. ^^hbW

Whether it's memory, motherboards, I/O boards, enclosures, or any of our family of products, CompuPro"" delivers what you want at prices you can afford.

Looking for memory? Our boards are fully static, low power, run at 4 or 5 MHz, support a number of popular busses, include a 1 year limited warranty, and generally come in 3 configurations to suit your exact needs. For lowest cost, choose an "unkit" with sockets and bypass caps pre-soldered in place for easy assembly. When you can't wait to get going, order one of our assembled versions. For critical systems, specify boards qualified under our Certified System Component (CSC) high reliability program. These boards are extensively tested, burned in for at least 200 hours, and are immediately replaced in event of failure within 1 year of invoice date.

Looking for other peripherals? We mix leading edge technology, design savvy, and volume buying to deliver the right product at the right price. See our list below for pricing.

250ns16K

T^5*fik^ -wV- dynamic RAMs

»"***" 8/$64!

Memory name

Buss & Notes

Unkit

Assm

CSC

8K Econoram* HA

S-100

$149

$179

$239

16K Econoram IV

S-100

$289

$339

$429

16K Econoram VIIA-16

S-100

$299

$349

$439

24K Econoram VIIA-24

S-100

$419

$499

$605

16K Econoram IX-16

Dig Grp

$319

$379

n/a

32K Econoram IX-32

Dig Grp

$559

$639

n/a

32K Econoram X

S-100

$549

$669

$789

32K Econoram XI

SBC/BLC

n/a

n/a

$1050

16K Econoram XIIIA-16

S-100 (1)

$349

$419

$519

24K Econoram XIIIA-24

S-100 (1)

$469

$539

$649

32K Econoram XIIIA-32

S-100 (1)

$579

$699

$849

16K Econoram XIV

S-100 (2)

$299

$359

$459

16K Econoram XV-16

H8(3)

$329

$395

n/a

32K Econoram XV-32

H8(3)

$599

$729

n/a

Perfect for memory expansion in a number of machines (TRS-80** Model I and Model II Exidy Sorcerer, Heath H89, Apple, etc.), and you can't beat our price: 8 high speed chips for $64! Add $3 if you'd like 2 dip shunts plus TRS-80* * programming instructions to expand memory These are 250 ns (4 MHz), dynamic RAMs... but quantities are limited, so hurry is you want to take advantage of this super deal. "TRS-80 is a trademark of the Tandy Corporation.

PASCAL/M' + EMORY SPECIAL

PASCAL can give a microcomputer with CP/M more power than many minis. For a limited time only, you can buy an assembled Econoram X, plus our totally standard Wirth PASCAL/M"" 8" diskette, for $799 (regular combined price, $999). Includes manual, plus Wirth's definitive book on PASCAL; specify Z-80 or 8080/8085 version. Diskette is also available separately for $350.

'Econoram is a trademark of Godbout Electronics

(1) Compatible with all bank select systems (Cromemco, Alpha Micro, etc.); addressable on 4K boundaries.

(2) Extended addressing (24 address lines). Single block addressable on 4K boundaries.

(3) Bank select option for implementing memory systems greater than 64K.

$85 unkit

4 independently addressable 4K blocks, with dipswitch selectable jump start built right into the board. Includes all support chips and manual, but does not include EROMs.

c

S-IOO MEMORY

THESE PRODUCTS ARE GENERALLY

AVAILABLE FROM YOUR LOCAL

COMPUTER STORE.

$59 unkit

MANAGER BOARD $iooacsc

Add bank select and extended addressing to older S-100 machines (Altair, IMSAI, Sol, and others). Use with our new extended addressing boards, or retrofit our high density Econorams for use with the Memory Manager to get added memory space for your computer.

ACTIVE TERMINATOR

$34.50 kit

Plugs into any S-100 motherboard (although ours don't need it) to reduce ringing, crosstalk, noise, and other buss-related problems.

MULLEN S-IOO

$49

kit

THE GODBOUT COMPUTER BOX

$259 desktop, $299 rack mount (introductory price)

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Circle 122 on inguiry card.

BYTE February 1980 173

use an in-line female 1/8 inch phone jack and avoid having to keep the jack above possible outside grounds. A short shielded cable exits the meter box, terminates in an 1/8 inch phone plug, and plugs into the recorder ear jack.

That is all there is to it! If your cassettes are marked with the meter readings that are obtained on playback, you should be able to load almost anything on the first pass. If you see the level on playback begin to drop over a period of time, you will know that the tape heads need cleaning. I think you will find that this is a useful accessory. ■

Algebraic Identities Are Not Numerical Identities

Alan B Forsythe PhD, University of California Los Angeles Department of Biomathematics, School of Medicine Los Angeles CA 90024

The development of statistical software can present some adverse computational problems. In "Elements of Statistical Computation" (January 1979 BYTE, page 182), I demonstrated the tip of this iceberg with two algorithms

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for calculating the standard deviation for some data. The first algorithm, the one given in many texts, incorrectly gives zero as the answer. The simple modification given in that article corrects the defect. This clearly shows the fallacy of simply coding the computational procedures given in standard textbooks.

Subsequently, J G Bliss erroneously speculated that a division by four rather than five (N-l rather than N) probably accounts for the incorrect answer. (See "Statistical Computations Recomputed," June 1979 BYTE, page 193.) As my original article pointed out, the root of the problem is the fact that digital computers have finite precision. Algebraic identities are not numerical identities. Thus, when very large numbers are added or subtracted, the last few digits are lost due to truncation. When faced with deviations from large numbers, the user has to be very careful with the computational formula employed. That is why a better answer can be obtained using the last algorithm given in the article.

A simple example on the TRS-80 is:

PRINT 1000000 + 1

The resulting display shows 1E6. That is, one million plus one is reported to equal one million. The single-precision representation is not adequate for this problem.

The heart of the computation of the standard deviation is the sum of the squares of the deviations about the mean. Algebraically this can be deduced from the sum of the squares of the individual values and their sum. The original article demonstrates that the use of this algebraic identity leads to the subtraction of two very large numbers and thereby to the loss of the critical digits. The computed result for the sum of squares of the deviations is zero. It is now clear that if a computationally poor procedure yields zero, then it certainly does not matter if we divide by five or four. In either case, we still get zero.

Why is there any question whether to divide by N or N —1 in the calculation of the standard deviation? When given the values for the entire population, then divide by N; when working with a sample, then divide by N — 1. The example in the original article was a sample from a much larger population and so the correct divisor of N —1 was used.

Mr Bliss references an accounting and auditing textbook. If, in the auditing situation, in order to verify each and every of the thousands of bills paid, then the divisor should be N. However, if only a sample was drawn, then N — 1 is the appropriate divisor for the standard deviation.

Since I am a statistician and not an accountant, I will not argue with Mr Bliss about accounting. If his usual procedure is to exhaustively study all transactions, rather than a sample, then he should divide by N. My experience with sampling from large populations has been that great economy of effort can be realized without much loss in precision with the use of an appropriate sampling plan.B

REFERENCES

1, Bliss, J F, "Statistical Compulations Recomputed," BYTE, June 1979, page 193.

2. Forsythe, A B, "Elements of Statistical Computation," BYTE, January 1979, page 182.

174 February 1980 © BYTE Publications Inc

Circle 123 on inquiry card.

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BASIC Formatted Output

Listing 1: BASIC source code for the editing routines. Lines 100 to 927 are the driver program for the text editor. Lines 9000 to 9997 are the actual text editor. The editor is located at a high line number so it may be used with many BASIC programs. When using the editor, care must be taken not to use any line numbers in your driver program higher than 9000. The editor is broken into several routines. Lines 9000 through 9185 define the format that will be used. The format statement will be familiar to readers who have worked with FORTRAN format statements. Lines 9200 to 9268 parse the format statement. The parsed format is stored in arrays V$ and V as described in the text.

Lines 9300 to 9548 are the free format input routine. The data is entered with commas separating the individual units. This routine then takes the data and puts it into the desired form.

Lines 9600 to 9997 take care of formatted output. The format used is a table developed by a routine such as that in lines 9200 to 9268.

I oo

1 I D 200

2 I 0 220 2 30 240 250

2 60 300

3 I 0 3 20 330 3 4 0 3 50 360 3 70 375

3 80 384 386 390 400

4 I 0 4 20 4 2 5 4 3 0 44 0 4 S Q 4 6 0

4 7 0

5 0 0 5 I 0 5 2 0 5 3 0 5 4 0 5 5 0

REM TEST PROGRAM FOR FORMAT SUBROUTINES

REM

DIM V$ ( 30 ) . V( 30 ) . Y( 3 , 30 )

E$="ENTER"

FORMAT"

FREE FORM"

FORMATTED"

STRINGS IN QUOTES

&. VAR I ABLES "

INSTRUCTIONS (Y N" GOTO 3 7 0 PRINT "USE CODE

1 =";G$

2 = " ; G $

3 =";G$

4 = INPUT" ENTER CODE

G$ = " H$ = " I $ = " J $="

KJ = " I NPUT IF Y$ PR INT PR INT PR INT PR INT PR INT INPUT PR INT I F A$ I F A$ A=VAL(A$) ON A GOTO 4 00 PR I NT E$ .G$ INPUT F$ GOSUB 9060 PR INT: PR INT FOR K=I TO Y9 PR I NT Y( I . K ) : NEXT K PR 1 NT GOTO 3 70 PR I NT I: J ; Ci S

OR N):';YS

FOR FOLLOWING TESTS"

& TABLE" ";H$;K$

",!$;" STRING";KS ;G$;".";HJ;" OUTPUT" AJ

G$

5" GOTO END" OR

320

A$="E"

THEN STOP

500,700,800

Y ( 2 , K ) : Y ( 3 , K )

I NPUT

PR I NT 1 NPUT GOSUB GOSUB

F$

E $ ZS

9 0 6 0 9 4 0 0

H $ ; J $

William D Roch

24000 Bessemer St

Woodland Hills CA 91367

Listing 1 continued on page 178

If your BASIC interpreter has a PRINT USING capability, you should have no trouble printing reports or other similar output. If not, then you are at an apparent impasse with the standard BASIC output that leftjustifies everything at fixed positions on a line, an approach that has many limitations.

The routines in listing 1, lines 9000 to 9997, solve this problem and produce a formatted output. Also included are routines for reading an unformatted string and placing the fields in numerical or string arrays, and a routine forestablishingarraysfor aformatted input record. In addition, lines 100 to 927 are a test program that can be used to get the feel of how these routines work.

Why Format Records?

There are several advantages to working with formatted string records:

• The position of each field in a record is always constant.

• Only one variable name is needed to input, read or print. Counting fields when there is more than one record type involved is no problem — you need only check a record type code and break up the record with the proper format statement.

• Records may be created and changed with one string type editor rather than an individual program or modification for each set of records.

• Most business type applications use formatted records.

Format Definition Routine

Our primary concern is describing the appearance of the record format to the rou

Text continued on page 185

176 February 1980 © BYTE Publications Inc

Circle 126 on inquiry card.

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Circle 127 on inquiry card.

BYTE February 1980 177

Circle 128 on inquiry card.

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Listing 7 continued:

5 60

5 7 0 5 8 0

5 90

6 0 0 6 I 0 6 2 0 6 3 0 64 0

6 50

7 00 7 I 0 7 20 7 30 7 4 0 7 50

7 60 800

8 I 0 8 2 0 8 3 0 84 0 8 5 0 8 60 8 7 0 8 7 5 8 8 0

8 9 0 900

9 2 7 8 9 9 8

8 9 9 9

9 00 0 900 3 9 00 6 900 9 90 10 9 0 12 90 15 9 0 18 902 1 902 4

902 7 90 3 0

903 3 90 3 6 9 0 3 9

904 0 904 ] 9 04 2

904 5 9 04 8 90 5 1 9054

905 7

905 8 9060

906 9

907 2 9 0 7 5

908 1 908 4

908 7

909 0 909 3 909 6 909 9 9 100 9 10 3 9 10 6 9 10 9 9 112 9 115

PR I NT FOR K PR INT NbXT PR INT FOR K PR I NT N k X T PR I NT GOTO 3 70 PR INT tS INPUT GOSUB PR INI INPUT GOSUB GOTO

PRINT I TO V I V$ ( K )

PR I NT I TO V2 V( K )

;G$ FS 9 0 60

PRINT Z$

9 2 60 5 60

STRINGS'

NUMBkRS'

k $ ; I $ : J S

J $

OUTPUT":G$

NT U$ : PR INT

FORMAT DEFINITION SUBROUTINk [SUB I/O IA.0

THIS ROUTINE BRkAKS UP STATkMkNT INTO A TABLk

= " ( A3

4X 3 4 2

PR I NT fc$ ;G$ INPUT FS GOSUB 9060 PR I NT kj :HJ INPUT Z$ PR I NT k$ ; " INPUT FS GOSUB 9060 GOSUB 9400 GOSUB 9650 PRINT: PR GOTO 3 70 REM RkM RkM RkM RkM RkM RkM

RkM kXAMPl.t RkM RkM RkM RkM RkM RkM RkM RkM RkM RkM RkM RkM RkM RkM RkM RkM RkM RkM RkM V I = I V2= I V5= I Y9= I

Y( 2 . 1 ) = 1 W$= " "

U S = * A I F X .)." KOR V7 = 2 TO l.EN( KJ ) X$=MID$(F$.V7, I ) FOR V8=I TO 8 IF X$=MIDJ(US.V8.I) NkXT V8

IF X$>="0 " AND X$<="9 " PRINT •FORMAT kRROR (" STOP

IF V8 <5 GOTO 9 12 1 V8 =V8 - 4

F$ A3 4X

2 F7 X

3 I 6

INPUT

FS OUTPUT:

V I

V2

Y(1.K)

Y(2,K)

Y(3,K)

Y9 VARIABkk

A FORTRAN' TYPk FORMAT FOR USE WITH [SUB 1B.IC,

6 ) "

ID]

2 F 7 . 2 . X . 3

CHAR STRING (3A - BAD kNTRY)

BkANKS (4X6 - 6 IGNORkD)

REAL NOS OF 7 CHARS W/ 2

BkANK

INTkGkRS 6 CHAR LONG

FORMAT

DIM AS RkQUI RED

- STRING FI ELD COUNT

- NUMBER FIELD COUNT ) - TYPE l=STRING. 2=1NTEGER. 3=REAL. ) - FIELD START POSITION IN INPUT OR ) - LkNGTH OF FIELD

- NO OF FIELDS INCLUDING BLANKS + I NAMES USED:

DECIMAL PLACES

4=BLANK OUTPUT RECORD

F$.U$.W$.X$.VI,V2,V3.V4,V5,V6.V7.V8.V9.Y(I.K).Y9

GOTO 9 112

GOTO 9 142

X$ ; " ) "

Listing 1 continued on page 180

178 February 1980 © BYTE Publications Inc

Circle 129 on inquiry card.

Circle 130 on inquiry card.

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180 February 1980 © BYTE Publicalions Inc

Listing 7 continued:

9 118

9 i : i

9 13 0 9 13 3 9 13 6

9 119 9 14 2 9 14 5 9 148 9 15 1 9 15 3 9 15 4 9 15 7 9 16 0 9 16 1 9 16 5 9 16 6 9 16 9 9 17 0 9 17! 9 17 2 9 17 5 9 17 8 9 18 1 9 18 4 9 18 5 9 19 0 9 19 2 9 2 0 0 9 2 0 3 9 2 0 6 9 2 0 9 9 2 12 9 2 15 9 2 18 9 2 19 9 2 2 1 9 2 2 4 9 2 2 7 9 2 3 0 9 2 3 3 9 2 3 6 9 2 3 9 9 2 4 2 9 2 4 5 9 2 4 8 9 2 5 1 9 2 5 4 9 2 6 0 9 2 6 6 92 69 9 2 7 2 9 2 7 5 9 2 7 8 9 2 8 1 9 2 8 4 9 2 8 7 9 2 9 0 9 2 9 3 9 2 9 6 9 2 9 7 9 2 9 8 9 3 0 0 9 3 0 3 9 3 0 6 9 3 0 9 9 3 12 9 3 15 9 3 16 9 3 18 9 3 2 1 9 3 2 4 9 3 2 7

GOTO 9 13 9

V 9 = V 8

V 6 = V 6 + I

IF V6 = 2 THEN V5 =VAL(WS )

GUI (> 9 18 1 II- VI <> 4 GOTO 9 15 1

w$ =w$+x$

V6= I

GOTO 9 18 4 V4-VAL(W$)

I I- V 5 = 0 THEN V 5 = I II- V 9 = 4 rHEN V 4 = V 5 IF V9 = 4 THEN V5 =I FOR V3 = 1 TO V5

Y ( I . Y 9 ) = V 9

Y ( 3 . Y 9 ) = V 4

Y(2.Y9+I)=INT(Y(2.Y9)+V4) Y9 =Y9+ I

V7

II- V 9 = 2 IK V 9 = I N EXT V 3 V5 = I V6= I WS = " " N I: X I RETURN R EM RLM REM REM REM REM REM REM REM REM REM REM REM REM REM REM REM

OR V 9 = 3 THEN V I :

T li E N

v i + I

BREAKS UP A EORMATTED STRING SUBROUTINE

SUB

/O 1B.0]

I NTO I NTP

SUBROUTINE BREAKS UP A FORMATTED STRING RECORD FROM: READ FROM INPUT STATEMENT READ FROM DATA STATEMENT

FORMATTED INPUT ■ STRING MUST BE IN QUOTES (") INPUT STATEMENT USING BASIC PATCHED FOR USE WITH ROCHE MULT I -CASSETTE CONTROLLER STRING AND NUMBER ARRAYS BASED ON A TABLE BUILT THE PROGRAM OR FROM PARAMETERS CREATED BY [I/O IA.0]

I )

I NPUT

Z$

Y( K

Y9 REM OUTPUT: REM V$(I) REM V( I ) REM VARIABLE REM V$( I ) ,

V I =0 V2 = 0

FOR V 7 =I TO Y9ON Y(I,V7) GOTO

V I =V I + I

V J ( V I )=M1D$(Z$.Y(2 GOTO 9 2 90

V 2 = V 2 + I

V(V2)=VAL(MIDS(Z%.

NEXT V7

Z $ « " "

RETURN

REM

RIM

RIM

REM

REM

RLM

REM

RLM

REM

RLM

RLM

REM

REM

INPUT STRING

PARAMETER TABLE

NO OF FIELDS INCLUDING

BLANK FIELDS

- STRING FI ELD

- NUMBER FIELD NAMES USED:

ZS ,V( I ) ,VI ,V2,

ARRAY ARRAY

V7.Y(I,K),Y9

9275,9284,9284,9290

V7 ) . INT(Y( 3 ,V7 ) ) )

Y( 2 . V7 ) , INT( Y( 3 , V7 ) ) ) )

FREE FORM INPUT SUBROUTINE |SUB I/O ICO]

THIS ROUTINE ACCEPTS A FREE FORM INPUT STRING AND PRODUCES A STRING AND/OR NUMBER ARRAY BASED ON A TABLE BUILT INTO THE PROGRAM OR CREATED BY [SUB I/O IA] . BLANKS ARE USED AS DELIMITERS BETWEEN FIELDS. SIRING FIELDS CONTAINING BLANKS OR WITH LEADING OR TRAILING BLANKS MUST BE

ENCLOSED WITH A DELIMITER. NUMERIC FIELDS ARE EDITED FOR NON-NUMERIC CHARACTERS. IF THE INPUT STRING HAS TOO MANY FIELDS THE EXTRA FIELDS WILL

Listing 1 continued on page 182

Circle 133 on inquiry card.

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Circle 134 on inquiry card.

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Circle 135 on inquiry card.

BYTE February 1980 181

Circle 136 on inquiry card.

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• Dual intensity display

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• 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

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

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Listing i continued:

9 3 3 o

9 .i 3 i

9 3 .1 6

9 3 .1 9

9 3 4 2

9 .1 4 5

9 3 4 8

9 3 5 1

9 3 5 4

9 3 5 7

9 3 6 0

9 3 69

9 3 7 2

9 3 7 5

9 3 7 6

9 3 7 8

9 3 8 1

94 00 940 3

9 40 6

9 409

9 4 12

9 4 15

9 4 16

9 4 18

9 4 2 1

9 4 2 4

9 4 2 7

9 4 3 0

9 4 3 3

94 3 4

94 3 5

9 4 3 6

9 4 3 9 944 2

9 4 4 5

9 4 4 8

9 4 5 1

9 4 5 4

9 4 5 7

9 4 6 0

9 4 6 3

9 4 6 6

9 4 6 9

9 4 7 2

9 4 7 5

9 4 7 8

9 4 8 1

9 4 8 4

9 4 8 7

9 490

9 4 9 3

9 49 4

9 4 9 6

9 4 9 9

9 5 0 0

9 5 0 3

9 5 06

9 5 0 9

9 5 12

9 5 15

9 5 18

9 5 2 1

9 5 2 4

9 5 2 7

9 5 3 0

9 5 3 3

9 5 3 6

9 5 3 9

9 54 2

9 54 5

9 5 4 8

9 6 00

RbM Rl-.M RfcM RbM RLM RLM RLM RLM RLM RLM RLM

BE IGNORED.

IK THE INPUT STRING HAS TOO LEW K1ELDS THE EXTRA FIELDS WILL BL 'BLANKED' OR ZEROED'. FOR BLANK FIELDS - ENTER '0' FOR NUMERIC AND ONE BLANK ENCLOSED BY DELIMITERS FOR STRINGS.

INPUT Z$ Y( I Y9 DS

RLM OUTPUT

RLM RLM RLM RLM RLM FOR

V$ ( I ) VII) ERR VARIABLE

TO V2

DELIMITER MAY BE USED

D$ .V$( I ) V 3 = 1 TO V I

V J ( V 3 ) = " " NEXT V3 FOR V3=I V( V 3 | = 0 NEXT V 3 REM ANY DS-"#*

V I =0 V2=0 V4= 1 V5=0 V6= I WS = " " ERR= I

FOR V 7 = I TO LEN(Z$ )

IF Y(I.V6)<>4 GOTO 9 4 4 8

V6=V6+I

GOTO 9439

X$=MID$(Z$.V7.I)

IF XIODI GOTO 9 4 6 9

V 4 = V 4 + I

IF V7=LLN(ZSI GOTO 9 5 15 IF V4 = 2 GOTO 9 5 4 5 V4 » I

GOTO 9 545

II- X$ = " " GOTO 9 5 0 3 V3 = I

I I Y( I . V6 ) = I GOTO 9 4 9 3

II XS>= "0 " AND X$<= " 9 " IF X$="•" GOTO 94 9 3

IF X $ = " . " AND Y( I . V 6 ) = 3

- INPUT STRING

• PARAMETER TABLE

- NO OF FIELDS INCLUDING BLANKS + I

- DLLIMITER

- STRING FIELDS ARRAY

- NUMERIC FIELDS ARRAY

- I -OK , 2 - ERROR NAMES USED:

W$.X$.V(I).VI,V2,V3,V4,V5.V6.V7.Y9

GOTO 94 9 3

V6

GOTO 949 3 ) NOT NUMERIC"

PR I NT " F I LID ( LRR=2: RETURN

V 5 = V 5 + I

IF V5>INT(Y(3.V6)) GOTO 9 54 5 WJ=W$+XJ

IF V7=LEN(Z$) GOTO 95 12 GOTO 9 5 4 5

IF V4 = 2 GOTO 94 9 3

IF V3=2 GOTO 9 5 12

V 3 = 2

IF Y(I.V6I<>I GOTO 9 5 2 4

V I =V I + I V$ ( V I )=w$ GOTO 9 5 3 0 V2 =V2+ I

V(V2)=VAL(W$) V6=V6+I

IF V7=LEN(Z$) GOTO 9 54 8 V5 =0 W$ = " "

IF V6=Y9 GOTO 9 5 4 8 NEXT V7 RETURN REM FORMATTED OUTPUT SUBROUTINE

SUB I/O ID.0]

Listing 1 continued on page 184

182 February 1980 © BYTE Publications Inc

Circle 137 on inquiry card.

CP/M SOFTWARE TOOLS

NEW ED-80 TEXT EDITOR

ED-80 offers a refreshing new approach for the creation and editing of program and data files conversationally -and it saves you money. Its powerful editing capabilities will satisfy the most demanding professional - yet it can still be used by the inexperienced beginner. Look at These Outstanding Features:

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■ Provides you with all the features found on the large mainframe and minicomputer editors, such as IBM. UNIVAC. CDC. and DEC.

■ Commands include forward or backward LOCATE, CHANGE, and FIND; and INSERT, DELETE, REPLACE. APPEND, SAVE, PRINT, WINDOW, MACRO, TABSET, SCALE, DUMP, and others.

■ Compatible with existing CP/fvi editand text formatted files, with CBASIC, and with Microsoft's MBASIC, FORTRAN, COBOL, and ASSEMBLER.

■ CHANGE commands allow you to make conditional changes and to use variable length strings.

■ Designed for CP/M and derivative operating systems, including LIFEBOAT, CDOS, IMDOS, DOS-A, ADOS, etc.

■ GET and PUT commands for concatenating, moving, duplicating, and merging your edit files on the same or different diskettes.

■ Provides you with fast memory-to-memory COPY commands, and an intermediate buffer for copying lines over-and-over.

■ Saves your last LOCATE, CHANGE, FIND, and APPEND command for easy re-execution.

■ Simple line-oriented commands for character string editing.

■ Safeguards to prevent catastrophic user errors that result in the loss of your edit file.

■ INLINE command for your character-oriented editing.

■ Designed for today's CRT's, video monitors, and teletypewriter terminals.

■ Thoroughly field tested and documented with a comprehensive User's Manual and self-instructional tutorial.

And remember — in today's interactive programming environment — your most important software tool is your text editor. ED-80 is already working in industry, government, universities, and in personal computing to significantly cut program development time and to reduce high labor costs. Why not let ED-80 begin solving your text editing problems today? ED-80 is protected by copyright and furnished under a paid-up license for use on a single computer system. Single Density Diskette and Manual: $99.00. or the Manual alone: $20.00 (credited with purchase of the Diskette). Specify Disk make/model, 5" or 8". hard or soft sectored. ORDER NOW and we'll pay the postage!

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Circle 138 on inquiry card.

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BYTE February 1980

Listing J continued:

9 60 3 9 60 6 9 60 9 9 6 12 9 6 14 9 6 16 9 6 18 9 6 2 1 9 6 2 2 9 6 2 4 9 6 2 7 9 6 3 0 9 6 3 3 9 6 3 6 9 6 3 9 9 642 9 64 5 9 64 8 9 64 9 9 6 5 0 9 6 5 2 9 6 5 4 9 6 5 6 9 65 8 9 6 60 9 66 3 9 6 66 9 66 8 9 669 9 6 7 1 9 67 2 9 6 7 5 9 67 8 9 6 8 1 9 6 8 4

REM REM REM RbM RUM RbM

POSITION ZEROS ARE

INPUT:

VS ( I )

V( I )

Y(1.K)

Y9 OUTPUT:

U$ VAR I ABLb

- STRING FIELD ARRAY

- NUMBER FI ELD ARRAY PARAMETER TABLE

- NO OF FIELDS INCLUDING

- OUTPUT STRING RECORD NAMES USED

BLANKS + I

THIS ROUTINE ACCEPTS ARRAYS OF STRING AND NUMBER FIELDS AND PRODUCES A FORMATTED STRING RECORD BASED ON A TABLE BUILT INTO THE PROGRAM OR CREATED BY |SUB A/O TABLE BUILD PROGRAM]. NUMBERS ARE RIGHT JUSTIFIED. DECIMAL

REM OF REAL NUMBERS ARE HELD AND TRAILING

REM ADDED IF REQUIRED.

REM

RbM

REM

REM

REM

REM

REM

REM

REM

REM

REM

U $ = " "

V I =0 V2 = 0 FOR V9= 1

w$ = - "

V5=Y( I . V9 )

V3= INT( Y( 3 .V9 ) )

ON V 5 GOTO 9668.9689.9689.9669

V I =V I + I

FOR VB= I TO V3 IF V5<>I GOTO 967 5

Y$=M1D$ ( VS (V1 ) .V8 . 1 )

IF Y$="" OR V5=4 THEN Y5=" "

IF V5=2 OR V5=3 THEN ¥$»"•" W$=W$+Y % NEXT V8

U$.V$( I ).W$.Y$,V( I ) .VI ,V2.V3.V4.V5.V6.V7.V8.V9.Y( 1 . K ) .Y9

TO Y9 - I

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184 February 1980 © BYTE Publications Inc

Circle 139 on inquiry card.

Listing 7 continued:

THEN V7=V7+I " THEN V7=V7 - I

GOTO 9 7 0 1 9 7 0 1

Y$=MID$(Y$,2)

9 68 5 US=US+WS

9 68 7 GOTO 9 7 6 0

9 6 8 9 V 2 »V 2 +I

9 6 9 0 V7= I NT( V( V2 ) )

9 69 .1 V7 = 1.EN ( SIRS ( V 7 ) ) • I

9 6 9 4 Y S = S T R S 1 V ( V 2 )

9 69 6 II- II- KTS ( YS . I

9697 IK MIDSIYS.1,

9 6 9 8 II II-. I IS ( Y$ . I

9699 I f V ( V 2 ) > I . I) GOTO

9 7 0 0 V 7 = 0 . 0

9 7 0 1 IK I.EKTS ( YS . I )<> " - " THEN

97 0.1 V4=(Y(.1.V9)-I0).(V3«I0)

9 7 0 6 IK V 5 = 3 GOTO 9 7 2 1

9 708 IK V3 - l.l:N( Y$ ) =0 GOTO 97 16

9 709 KOR V8=l TO V.l-EEN(YS)

9 7 12 W$=W$+" "

9 7 15 NEXT V8

9 7 16 WS=W$+Y$

9 7 18 GOTO 9 7 5 7

9721 IK V7-t>-V3-V4 GOTO 96 69

9724 IK I NT( V( V2 ) )=V( V2 ) THEN Y$=Y$+"

9 7 2 7 V 6 = 0

9728 V7=V4+V7+I

9729 V 7 = V J - V 7

9 7 J I KOR V8= I TO VJ

9 7.1.1 IF I NT( V7+ . 005 )>(V8 - I ) GOTO 9748

97.16 V 6 = V 6 + I

9 7 .1 9 V$=MI D$ < YS . V6 . I )

9 74 2 IK V$ = "~ THEN V$="0"

9 7 4.1 W$=W$+V$

9 7 45 GOTO 9 7 54

9 74 8 W$=W$+" "

9 7 5 4 NEXT V8

9757 U$=U$+W$

9 7 60 NEXT V9

9 7 6.1 RETURN

9 9 9 7 END

Text continued from page 176:

tine. This is done with a FORTRAN type format statement which defines:

A = Alphabetic or String Field.

I = Integer Number.

F = Floating Point or Real Number.

X = Blank.

Table 1 shows how these formats are used.

The format definition routine takes the format string statement (F$) and converts it into a 3 column array (V). The first column defines the type of field: string, alphanumeric, integer, real, or blank. The second column provides the starting position of the field within the record. The third field provides the length of the field and number of decimal positions. This routine creates a parameter table that is used by the other routines.

The parameter table could also be built using values from DATA statements read into the proper variables thus eliminating the table build routine. Once the table is created, it can be used with INPUT, READ and PRINT

Copies of these routines are available for $5 on paper tape or Tarbell format cassettes for 8 K V3.1, 3.2 and 4.0 BASIC from Elliam Associates, 24000 Bessemer St, Woodland Hills CA 91367.

Record Description

Product Class

A2

Product Code

A6

Description

A15

Vendor Code

13

Quantity On Order

14

Quantity On Hand

14

Sold Year To Date

14

Unit Sales Price

F7.2

Format Statement

F$="(A2,A6,A1 5*13,314,F 7.2)"

Data Record

TWHD110V Tape Winder

107

45 37

123

27.00

•—.—■

—.—' —.—

-—,—

-—.—

V$(1)V$(2) V$(3)

V(1)

V(2) V(3)

V(4)

V(5)

statements to convert the input or output string into string and number array variables. Any number of formats may be used in a program, but the format definition routine must be rerun each time a different format is used.

Fixed Form Input

The normal action of BASIC requires an entry for each field listed as a variable with an INPUT statement. This is a nuisance when you have an input and output (IO) field record and the last five entries are blank most of the time. The fixed form input does not require that the trailing fields be entered, since they will be blanked or zero filled. It is sometimes easier to keep the keyed input in neat columns (fixed format) rather than following one field after another (normal BASIC).

Example:

Normal BASIC

14,16,98

1457,258,7

2,3,7

Fixed Format

14 16 98

1457 258 7

2 3 7

The main advantage is in inputting formatted records from cassette tape or floppy disk. (See formatted output section, para

Table J: Format statement and corresponding data record. The descriptions for formats used here are FORTRAN types. The product class is an alphanumeric quantity having two characters, the product code consists of six alphanumeric characters and the description of 15 characters. The particular vendor code is a 3 digit integer. The quantity on order, on hand and the number sold up to this date are all 4 digit integers. The unit sales price is a 7 digit floating point number with two digits after the decimal place and four digits before the decimal place.

February 1980 © BYTE Publications Inc 185

graph after next, for further discussion of external 10.)

Free Form Input

Now that formatted input has been presented, let's look at the advantages and disadvantages of free form input. The major advantage is that data fields need only be separated by a blank and the routine will reformat that field to its proper place in the input record. Strings and numbers may be intermixed, but strings containing leading blanks or blanks within the string must be enclosed with a delimiter. The routine delimiter is a pound sign (#), although any character might be used. Blank fields must also be enclosed with delimiters, and numeric fields require a zero. Each method has its advantages and drawbacks depending on the type of data being handled. An example is shown in table 2.

Table 2: In this example a free form Input is read by a formatting routine and stored on a record as indicated.

Example:

keyed input

format

record

TW HD110V #TAPE WINDER #107 45 123 27.0 F$=" (A2,A6,A15,I3,3I4,F7.2)" TWHD100VTAPE WINDER 107 45 123 27.00

Table 3: Examples of how the format will affect the data that is being output. Note that some of the resulting output formats are indented. This is a result of leading blanks created to satisfy the format requirements for certain cases.

Data Format

Format Statement

Output Format

ABCDE

A6

ABCDE

ABCDEFG

A6

ABCDEF

123

14

123

12345

14

* # # *

12.34

F6.2

12.34

12.3475

F6.2

12.35

12.

F6.2

12.00

11234.1

F6.2

******

Formatted Output

The formatted output routine uses the parameter table values and the variable array values in the V array and places them in the output string. Blanks as called out in the format statement are included. Strings are left justified (start in the first position of the field) and numeric values are right justified (any spaces appear on the left). Numeric values larger than the field call out cause the field to be filled with asterisks. Floating point (real) numbers with fewer than the required decimal places are zero filled. Numbers with more decimal places than the format allows are rounded as shown in table 3. Taking table 2 as an example input, the data could be printed with a different format such as in table 4.

About the Routines

The line numbers used by these routines are set high (above location 9000 in memory) so that BASIC programs can be written under them. Care must be taken that your programs do not have line numbers higher than 9000. All of the variable names used in each routine are listed in the comments. These variable names must not be used in your programs. All the comments are included before the routines so they may be deleted to save space.

More About Records

Obviously, it takes only a minimum amount of extra code to switch fields, add string constants and perform mathematical functions. Using the input data record of table 1, the transformations in table 5 may be made.

Once these routines are in your library, it is a simple matter to load them into memory, to key in your program and to add format statements."

Table 4: Format and example output using the format and the data in table 3.

Table 5: Some typical transformations that may be performed on the stored and formatted data. The last line is the result of these transformations using the given format.

F$="(A2,X,A6,X,A1 5,13,3 I5,F8.3)"

TW HD100V Tape Winder 107 45 37 123 27.00

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change a string

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186 February 1980 © BYTE Publications Inc

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BYTE February 1980

187

Beck Reviews

Let's Talk LISP

by Laurent Siklossy Prentice-Hall, Englewood Cliffs N] 1976 237 pages hardcover $14.20

Let's Talk LISP is a fun and useful book to read, at least for those of us who learn best when the material is presented in an interesting way. This is especially helpful for LISP, because for someone who is familiar with traditional programming languages, LISP seems very peculiar at first. After reading Let's Talk LISP and writing a few programs, I wondered how I had managed to avoid LISP for so long.

The structure of the book is extremely straightforward.

The first two chapters introduce the fundamental building blocks of LISP. After that, the reader is led through function definitions, recursion, MAP functions, and assorted elements of the language. Midway through the book, the author demonstrates how to write a LISP interpreter in LISP, and discusses the storage functions of LISP. At this point the reader has been introduced to almost everything in the language, but is probably not certain how to write a program. The remainder of the book consists of programming examples.

The first question which one should ask of a LISP book is how it treats language variations; LISP is not standardized. There are two major dialects (EVAL

and EVALQUOTE), and many variations between implementations of the same dialect. The author discusses both of the major dialects, and points out where implementations are likely to differ. I have used two versions of LISP: a large version running on an Amdahl 470 and a Z80 version which was adapted from Dr Dobb's Journal of Computer Calisthenics and Orthodontia, number 30. Neither of these implementations matched the language used in Let's Talk LISP, but neither of them required much work to make the sample programs run. In short, the book attempts to cover possible differences, and gets most of them, but unless you are using MACLISP at MIT, you will have to make some changes. If you want to learn LISP and you are not turned off by a lighthearted but thorough treatment of the subject, Let's Talk LISP is a good book to read.

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Godel, Escher, Bach: An Eternal Golden Braid

Douglas R Hofstadter

Basic Books

New York 1979

742 pages plus notes and

references, hardcover

$18.95

G'ddel, Escher, Bach is a book of youthful wisdom and deep beauty. It spans the domains of art, science and philosophy — a fact which evidently causes considerable consternation to book store clerks, who occasionally misshelve it with the "occult."

At some fundamental level, the works of Bach, Escher and Godel may be seen as variant manifestations of a single common theme. Hofstadter uses this theme of recursion or selfreference to unify his exploration of questions _nd issues from such apparently disparate fields as artificial intelligence and molecular biology.

Godel, Escher, Bach is an enchanting book, in the same sense that Lewis Carroll's writings are enchanting. Although Hofstadter, a contemporary American, writes more idiomatically and with less polish than Lewis Carroll, the book's childlike exuberance, together with artistic forms, whimsical passages and concealed meanings, make it a sheer delight. The entire book has the form of a fugue — it is what it is about. Prose and dialogues alternate. The latter are in the spirit of Lewis Carroll and each imitates the form of a particular Bach composition.

Hofstadter is a physicist by training and a computer scientist by vocation. Students of artificial intelligence will appreciate his deeply knowledgeable treatment of this subject. Of particular interest are his remarks concerning

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BYTE February 1980

189

representations of knowledge, and his speculations concerning the future of artificial intelligence. For example,

"Question: Will a computer program ever write beautiful music? Speculation: Yes, but not soon. Music is a language of emotions, and until programs have emotions as complex as ours, there is no way a program will write anything beautiful . . . To think — and I have heard this suggested — that we might soon be able to command a preprogrammed mass-produced mailorder twenty-dollar desk-model 'music box' to bring forth from its sterile circuitry pieces which Chopin or Bach might have written had they lived longer is a grotesque and shameful misestimation of the depth of the human spirit ..."

Psychologists and other scientists who study humans are customarily reluctant to deal with such elusive topics as "consciousness" or "free will." Hofstadter has no such reticence, and consequently contributes unique and appealing insights to these subjects. In view of the book's global frame of reference, it is important to stress that the author is not reckless. On the contrary, one of his topics concerns the "nature of evidence," and in this regard it is clear that his own implicit criteria of acceptable evidence are definitely conservative. Neither is he a bigot, scientific or otherwise. His approach to centuries-old problems and dilemmas is characterized by carefulness and fair-mindedness.

An interesting paradox arises from the observation that no two human brains are perfectly isomorphic; yet humans have a powerful ability to communicate with other humans, however remote in time or place.

Hofstadter invents the concept of a "partial software isomorphism" between the brains of people who have similar thinking styles. An analysis of "Jabberwocky" translations clearly reveals the impossibility of exact translation between even closely related languages. One cannot help thinking that Hofstadter's book itself must represent the ultimate challenge for a translator. The dialogues not infrequently contain more than two levels of meaning. There are puns and acrostics, word puzzles and number puzzles — indeed, levels of meaning sometimes communicate with one another.

Although the prose is tractable, it is manifestly impossible to convey the true flavor of the book or to completely describe its subject matter in a brief review. Perhaps the best synopsis is found in the book on page 370, where the author diagrams a "tiny portion" of his "semantic network." This

"tiny portion" contains more than 100 interrelated symbols including: Truth vs provability, Godel code, Genetic code, Recursion, Figure vs ground, Escher, Canons and fugues, RICERCAR, Holism vs reductionism, Minds, Computers, Turing and more. What Hofstadter has to say on these subjects is uniquely interesting because it is founded on knowledge, derived by honest (unprejudiced) reasoning and expressed with a simple lucidity.

In the past few decades, much has been said and written about "intelligence," a concept now suspect but once thought to have a clear intuitive meaning. Whatever human intelligence is, one feels that this book manifests its highest qualities. Godel, Escher, Bach is an exceptionally good book.II

W Lloyd Milligan 8604 Maywood Dr Columbia SC 29209

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CP/M 2.0

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CP/M is a trademark of Digital Research Inc. TRS-80 is a trademark of Tandy Corp. Circle 152 on inquiry card. BYTE February 1980 191

A Financial Analysis Program

John A Lehman

716 Hutchins #2

Ann Arbor MI 48103

Introduction

Financial analysis, as it will be used in this article, means the study and analysis of financial statements. Financial statements are the documents which are produced by an accounting system; they report the position of a firm (such as the balance sheets shown in table 1) and how well it has done over the last period (income statements). They are used both by small businesses and by major corporations. The latter are. required to make public statements in annual reports and in filings with the Securities and Exchange Commission; these statements serve as one of the primary sources of information to investors.

The program logic described in figure 1 is versatile enough to work on the financial statements of almost any company, although some statements may first need to be consolidated a bit. The basic tools used to analyze statements are ratios and percentages. These can be calculated for a firm, and then compared with both the firm's previous performance and with other firms in the same in

About the Author

John A Lehman is a doctoral student in business administration at the University of Michigan.

dustry. In this way, a comprehensive study can evaluate the position of the firm and identify trends in performance.

There are a number of different people who can make use of this sort of analysis. Investors form a major group. Those who wish to make their own investment decisions rather than follow the suggestions of a broker or other advisor, usually want to base their investments on something more than blind faith. The analysis of financial statements is a good way to begin evaluating prospective investments. Unfortunately, many investors wish to evaluate a fairly large number of possibilities. This may present problems because the detailed analysis of ratios and percentages needed to evaluate your investments requires a great deal of time to calculate. This is where the personal computer comes in. With this program, you can evaluate a set of detailed reports in about the same time it takes to calculate a simple percentage analysis with a calculator. The results may be used as is, or used as inputs to any statistical calculations which you wish to use. In short, a personal computer can significantly reduce the time spent on the tedious calculations involved in financial analysis, and leave the analyst more

time for creative thought.

Investors are not the only ones who can use this sort of program. Banks regularly use ratio and percentage analysis to evaluate loan applications from businesses. Many banks are well equipped with computing facilities. But the businessman who is applying for the loan is often not. A banker is likely to be impressed if the financial statements submitted with the loan application include ratios and percentages. Not only does it make the banker's job easier, but it indicates that the applicant is well prepared.

A pro forma statement is a useful indicator to provide. These are forecasts of your financial position at some future point (eg: when the loan falls due). The program will also calculate pro formas.

Aside from using all of these financial indicators to impress the bank, a small businessman might want to use them to analyze his business. Where are things going well, and what weaknesses could stand some attention? There is plenty of available documentation which shows how to interpret ratios and percentages, but again, the calculations are tedious.

This program might also prove useful for the financial analyst— professional or academic. Since I count myself in the latter category, I have

192 February 1980 © BYTE Publications Inc

Table 1: The financial statements from the MITS corporation before it was absorbed. These figures come from the Annual Report. This illustrates the format used in a standard financial report.

MITS INC Balance Sheet

December 31 1975 and 1974 Assets

Current Assets: Cash

Accounts receivable, less allowance for doubtful accounts of $5,500, $2,500 in 1974 (Note 2) Notes receivable, stockholder Inventories (Note 2) Current portion of prepaid expenses Total current assets

Property, plant and equipment (at cost) (Notes 2 and 3): Tooling

Transportation Shop equipment Office equipment Leasehold improvements Drafting equipment

Less accumulated depreciation

Other assets: Deposits Deferred portion of prepaid expenses

1975

$ 112,461

1974

$ 30,596

258,790

350

640,432

104,809

35,808

350

266,219

33,986

1,116,842

366,959

225,821

130,607

55,150

40,305

12,749

5,753

117,669

8,140

13,349

24,931

9,848

2,694

470,385 119,248

176,631 58,233

351,137

118,398

1,766 29,938

240

31,704

240

$ 1,499,683

$ 485,597

See accompanying accountants' report and notes to financial statements.

Liabilities and Stockholders' Equity (Deficit)

Current liabilities: Accounts payable ■ trade Customer deposits Working capital loans (Note 2) Current portion of long-term debt

(Note 3) Accrued liabilities

Total current liabilities

Deferred portion of long-term debt

(Note 3) Commitments (Note 4)

Stockholders' equity:

Common stock, $.01 par value, 25,000,000 shares authorized, 947,495 shares issued in 1975, 902,940 shares issued in 1974

Additional paid-in capital

Retained deficit

Less treasury stock, at cost, 1,100 shares

1975

1974

$ 331,791 455,425 321,463

$ 171,279

85,517

406,963

39,288 83,327

8,602 17,944

1,231,294

690,305

118,626

1,080

9,475

294,683

(153,295)

150,863

1,100

9,029

250,575

(465,392)

(205,788)

149,763 $ 1,499,683

(205,788) $ 485,597

Table 1 continued on page 194

February 1980 © BYTE Publicalions Inc 193

Table 1 continued:

MITS INC

Statement of Income (Loss)

Years ended December 31 1975 and 1974

Sales

Cost of sales

Gross profit

Expenses: Selling

Administrative Other income and deductions

Net income (loss)

Net income (loss) per common share

1975

1974

$ 3,240,772

$

959,972

2,112,551

794,579

1,128,221

165,393

441,596 265,274 109,254

152,407

176,295

50,795

816,124

379,497

$312,097

$ (214,104)

$ .33

$

(.24)

See accompanying accountants' report and notes to financial statements.

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no doubt that the program is indeed useful for such people. I wrote this program to handle analytical problems which I had to perform quite often. Again, the outputs from this, program may be used as they are, or as inputs to additional analyses.

Overview of the Program

The program in listing 1 is set up to' work on standard financial statements with data for up to ten periods. It is arranged to use a standard chart of accounts for the income statement and balance sheet. Since the chart of accounts is not very specific, more detailed statements will have to be condensed first. This would be necessary for analysis in any case, since ratios are not usually calculated on the basis of all of the different categories of inventory, etc. The ten periods allowed may be either in years or quarters, and the output will be labeled correspondingly. Ten periods were selected since many annual reports and other published financial statements include ten-year summaries.

For whichever periods are entered, the user may select either a ratio analysis, a percentage analysis, or both. The ratio analysis subroutine calculates fourteen different ratios.

194 February 1980 & BYTE Publications Inc

Circle 153 on inquiry card.

f START J

INITIALIZE CONSTANTS

INPUT

FINANCIAL

STATEMENTS

% ANALYSIS

PERFORM

PERCENTAGE

CALCULATIONS

RATIO

PERFORM

RATIO

CALCULATIONS

YES

c

MD )

I 1

| FLAG | <

— i

' USING

INCREMENTAL . CHANGE I I

CHANGE

PERFORM

PERCENTAGE

CHANGE

I INCOME ■ —| STATEMENT

ANALYSIS OF I-■ PROFORMA

INCREMENT

MAKE AN

INCREMENTAL

CHANGE

% ANALYSIS

PERFORM

PERCENTAGE

CALCULATIONS

YES

RATIO

PERFORM

RATIO

ANALYSIS

% ANALYSIS

PERFORM

PERCENTAGE

ANALYSIS

J

<4NOTHER\YES „ PROFORMA^

?

f END )

Figure 1: Flowchart of the financial analysis program.

February 1980 © BYTE Publicalions Inc 195

Listing 1: BASIC listing of the financial analysis program. The entire program and the memory space required for BASIC can be stored in 16 K bytes of memory. A sample output of the program analyzing two years of data is also included.

i o

2 0 2 1 22 23 24 25 26 £7 28 29 30 40 50 60 70 BO 90 1 00 1 10 1 20 1 30 I 40 1 50 1 60

1 70 180 190 200

2 10 220 230 240 250 260 270 280 290 300

3 10

3 20 330 340 350 360 370 380 3<sr, 400

4 10 420 430 440 450 460 470

4 8 0 490

5 00 5 10 5 20 530 5 40 5 5 0

5 60 570 580 59 0 f DC

6 1 0 6 20 630 640 650

6 60 670 630 690

7 00

°EM FINANCIAL ANALY5I 5, RATIO i %

DEM ALSO DOES P°OFORMAS USING 7, Of ABSOLUTE INCREMENTS

REM Z(33, 11) IS THE MATRIX FOR THE FIN AN CI AL STATEMENTS

REM PERIOD ELEVEN IS THE SPACE FOR THE PROFORMAS

REM NS IS THE ACCOUNT NAMES VECTOR

REM RJ IS THE RATIO NAMES, RC ) THE RATIO VALUES

REM 0 INDICATES QUARTERS OR YEARS, CS = COMPANY NAME

REM EISA FIRST CELL POINTER, M IS A LAST CELL POINTER

REM SWITCH CHANGES BETWEEN THE TELETYPE AND THE VIDEO DISPLAY

Rjft, ,ip to TEN PERIODS CAN BE TESTED FOR. STATEMENTS 2 1-29

REM SHOULD BE REMOVED IF YOU HAVE 16 K OR LESS OF MEMORY.

REM BY JOHN A LEHMAN

DIM Z( 33, 10>,NSC33),R(13, 1 3), RS( 13)

FOR 1 = 1 TO 33:DEAD Nsri):NEXT I

DATA "SALES", "OTH REV"* "TOT I N C", "C G S", "DE PR", " SGA"

DATA "INT", "TAX", "DI V", "TOTAL EXP", "NET INC"

DATA "CASH", "RCBLS", "INV, "PPL ITEMS","TOT CUR"

DATA "LAND", "BLDG/EQU", "ACC DEPR", "TOT FIXED", "OTH AS"

DATA "TOT ASTS","ACCTS PBL", "NOTES PEL", "CUR LT"

DATA "OTHED L.1AB", "CUR LIAB","LT DEBT", "TOT LIAB"

DATA "C STK", "APIC", "RE", "TOT CR"

FOP 1=1 TO 13:READ Rf(I):NEXT 1

DATA "CUDRENT", "ACID", "RCBL TO","INV TO", "ASSET TO", "PROF ON SALESDATA "ROA", "ROI ", "EPS", "PAYOUT", "EBT-EQU", "T INT EARN ED", "BK/SHARE"

INPUT "QUARTERS OR YEARS",'AS

IF LEFTSf AS, 1 ) ="Q" THEN 210

IF LEFTSC AS. 1) = "Y" THEN 250

GOTO 160

REM QUARTERS. LS IS A LABEL

LS="QUARTEPS"

LET 0=.2 5

REM AN INCREMENT

GOTO 2 70

L$="YEARS "

0=1

"COMPANY NAME",1 CI

INPUT INPUT INPUT 7 "OK.

"FOR HOW'MANY PERIODS LO YOU HAVE F1GURES";N

BEGINNING WITH JANUARY OF WHAT YEAR";Y

FIGI'°ES FOR "JNJLj;" BEGINNING IN ";Y FOR J=l TO 3 3 F0D K=l TO N Y1 = 1NT( Y+ 0*K- 1 ) ? NIC J),-" FOP "JY1 INPUT Z(J,K) NEXT K NEXT J

FOR J=1 TO N

? •■<« SHARES OUTSTANDING PERIOD "JJJ "?" INPUT Hi J) NEXT J

INPUT"C0RRECT10NS",-AS:'IF LEFT$(AI, 1)="N" THEN 440 INPUT "WHICH ACCT* g PD#"; J, K : 1 N PUT" VAL UE",' Z( J, K ) : GO TO 420 B=1:REM 1ST CELL POINTER SW1TCH

'"DO YOU WANT t LIST OF COMPARATIVE FINANCIAL RATIOS'" - •■PLEASE ANSIER YES OR NO. THE ALTERNATIVE IS COMPARATIVE V

|W rl J >i J

IF LEFT<(A5,1)="Y" THEM 530

IF LE FT$( A5, 1 ) ='•&)•' THEN 540

? "PLtAcE ANCWEQ YEC 0° NO"

GOTO 4 60

COSUB 1030

INPUT "DO YOU WANT COMPARATIVE •'. FROM INCOMES STMT 4 bS";AJ

IF LE F TI( PI, 1 ) = "Y" THEN 590

GOTO 9 40

? "PLEASE AN SUE" YES OP NO"

GOTO 5 40

GO SUB 1310

GOSl'B 1410

INPUT "DO YOU WANT TO CREATE A PFOFORMA INCOME S TATEMEN T" i A3

,.Y.

THEN 650 THEN 1340

IF LEFTJf A J, I ):

1 F LEFTIC At, 1 ) =

P0T0 610

INPUT"D0 YOU WANT TO USE X CHANGES FROM LAST PERI Of; AS

IF LEFTJC AI, 1 )="N" THEN 710

IF LEFTSf AS, 1 ) ="Y" THEN 690

GOTO 650

GO SUB 1510

GOTO 940

Listing 1 continued on page 19

These include the following: current, quick, acid test, accounts receivable in days, inventory turnover, asset turnover, profit on sales, return on assets, return on investment, earnings per share (simple), dividend payout, debt/equity, times interest earned, and book value per share. A detailed description of the use of these ratios and how they are calculated is included in the glossary at the end of this article. Percentages will be calculated for each period in two groups. Income statement items will be presented as percent of total sales; balance sheet items will be presented as percent of total assets.

In addition to the above analyses, the program will calculate pro forma income statements and balance sheets. As I mentioned earlier, a pro forma statement is a prediction of what that statement will look like at a given time. The statements for the last period are the basis upon which the program calculates pro forma statements. These may be done by assuming a constant percentage change for all accounts, or by giving dollar amounts by which each account is predicted to change. As well as calculating the pro forma statements, the program will do ratio and/or percentage analyses on the pro formas if desired. This is particularly useful when examining the effects of alternate possibilities. It is possible to come up with several alternatives for the coming period and observe the forecasted result for each one.

Computer Program

The financial analysis program has been written in BASIC and runs in 16 K bytes or more, including the space required for BASIC, but not including the space required for the system monitor. If you are running it with only 16 K (as I do) you will either have to remove some of the remark statements from the listing or adjust the dimension (DIM) statement to handle less than ten periods.

The only peripheral-dependent part of the program is the SWITCH statement which occurs at lines 450 and 1840. This is used to switch the logical console device between user defined and the Teletype. The configuration upon which I run it allows me to set up all of the statements

196 February 1980 © BYTE Publications Inc

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BYTE February 1980 197

Listing 1 continued: u- g vjcjeo display anc) then have

710 ? -ro you want to make INCREMENTAL changes fpom" , rpsiilts nrinted on the Teletvoe If

720 input -the last pe°ict ufiNG amounts of change-;ai trie results primed on tne i eieiype . ir

730 if left$<a$, i) = "N ■• then 8eo your system does not allow for the

740 if left^aj, n="Y- then 770 SWITCH command, you can leave it

750 ■> "PLEASE ANSWER YES OR NO" . , .,, u

7 60 goto 710 out with no ill effects.

770 ? "eo voi' want ji'st the income statement (enter is) or" If yOU have more than 16 K bytes

780 input-income statement*balance sheet (enter anything else)";z5 0f memory, you may want to extend

790 IF Z$="IS" THEN 840

800 F=33

the strings from lines 60 thru 120 and

bio pem points to last account to BE usee 140 thru 150. This will make the out

8 20 go sub 1700 put more readable.

830 GOTO 360 r S

8 40 F= 1 1

850 G0S"F 1700

860 INPUT "DO YOU WANT A RATIO ANALYSIS OF THE PROFORMA (IF ANY)"! AS

870 IF LEFTJfAS, I)="Y" THEN 890 j

880 IF LEFTJfAS, 1 ) = "N " THEN 940 j

390 LET N =1 j

900 if zs<>"is" then 930 Glossary

910 ?"CAN'T CALC WITH JUST INC STATEMENT"

920 goto 940 accounts receivable in days: Ac

930 gosub 1030 00„r„„_„, . counts receivable are divided by total

940 INPUT "DO YOU WANT A 7. ANALYSIS OF THE PRO F 0 RM A" J A$ •»

950 if lefts( a$> l > = "Y" then 930 sales to produce receivable turnover

960 if lefts(ai, d="N" then iooo per year, then divided by 365. This

970 GOTO 940 . . ». ,. t • r ,

980 fJ=M gives some indication of how fast

990 go sub 1310 receivables are being collected.

iooo input -co you vant another proforma-;as Values vary with industry. Gener-'

1010 IF LEFTKAJ, 1 )»"Y" THEN 650 n ,i i w i r j

1020 if leftjcas, l) = "n " then 1840 ally, the lower the number of days, I

1030 pem subroutine to calculate patios the better.

1 040 FOR i = b to n

1050 i«i,i>»zci6,i>/Z(27,1)»hlm current ratio asset turnover: Net sales divided by'

loeo «fa,i>-czM2,i>+2H3,i)>/z<2?,niBEM acid test average total assets This is one indi-<

1070 of 3, I )=365/fZ( 1,1 )/Z< 13, I) ) : REM RCBL LAYS uuciuge luiui Ubbeib. l nib lb one inui

1080 9f 4, i > = 365/( z( n, i -,/?_(. i n, i)) : pem inv to cation of how well assets are being1.

1090 Of 5, I )=Zf- 1' 1 >/Z(22, I) : «EM ASSET TO usecj

1100 Of 6, iy-ZC 1 M )/?,< 1,1) ! OEM PROFIT ON SALES

L 1 1 Q R( 7, I ) = .*( 1 1 , I > f < 22, I) : RE M ROA

1120 R(S, I >='( 1 1, I)/( '( 33, I )-Z(29, I > > : =EM "01 ,..,.,,

1130 p(9, i) = tt 11, i >/h< i >: o£.m eps divided by the number of shares.

M40 r( 10, i> = z(9, i >/zf i i, i > :°fm Ei'.' po How much the shares of stock are

1150 R( 1 1, I )=Z( 29, I >/Z(22, I > : BEM D/E

1160 H(l?,I)=(7.nl,l)t7<9,l)*7-'5.n*?.(7,I))/'.(7,I):

1170 °f 1 3, I> = ( Z< 33, I >-Z< 29, 1 ) )/H( I ) : REM BK/SHARE i. u VI ± t- ■ •

180 next i current ratio: A current account is

1190 input"mo"e paper to top of page a press a KfcV'JAi cash or anything which can be con

laoo ? cj,"°atio analysis-:? verted into cash within one year. The ■

1210 ? "OATIOS FOR "JNJLI,,-" BEGINNING IN "JY:? . . . ,,,..,. 1

1220 for 1 = 1 to 13 current ratio is obtained by dividing

1230 ? Rsfi) the current assets by current liabi

! 250 y^nt^VJ- ,, liiies' V ihe ™tio is one, debts which

12 60 ? Yi,R(i,J) must be paid within one year are just.

1270 next j covered by assets which are expected]

1230 NEXT I:?:?:? , . , . , . -r

1290 return to "e received within one year. 10

1300 rem subroutine to do i analysis maintain financial peace of mind the''

1310 input -move paper to top of page 4 press a KEY-jAj current ratio should be greater than'

1320 ? "INCOME STATEMENT ITEMS AS % OF TOTAL INCOME" S

1 330 FOP 1 = 1 T01 1 °ne

1 3 40 ? N If I 3 ii,. -»• 1 »...»..

1350 for j=b to n debt/equity ratio: lotal liabilities

i 360 Yi = iNTfY+o«j-D divided by total assets (also referred

l 370 R(J, l) = Z( I, J)/Z( 3, J)* 100 I 380 ? Yl, Pf J, l ) :NEXTJ

book value per share: Common stock divided by the number of How much the shares of stc worth in an accounting sense.

to as total equities). How much of the •

139 0 nfxt iti firm's capital was furnished by

1400 retupn creditors as opposed to owners. It

1410 ? "B.S. ITEMS AS •% OF TOTAL ASSETS":? , , , , , , , I

1420 for 1 = 12 to 33 varies by industry, but the lower the

1430 ? N$fi), better for safety, and the higher the

1450 Y^iNTfMLj-n better for earnings per share. This,

1460 Rf j, l) = z( i, j >/zt 22, j) * i oo contradiction is due to something'.

1470 ? yi, Rf J, i) :next j called leverage, which is a fancy term

1430 NFXT 1:?:?:? , . ° , I '

1490 return ior mvesttng other peoples money,

isoo rem subroutine to calculate proforma with z changes and keeping the profits.

1510 M=N+1:REM SAVE LAST CELL POINTER

1520 b=m dividend payout: Cash dividends'

1 530 FOR 1=1 T09

1540 ? "CHANGE FOP ";NftI>

divided by net income. This shows how much of earnings were paid to \ Listing l continued on page 200 investors as opposed to those kept for

198 February 1980 © BYTE Publications lnc

Circle 157 on inquiry card.

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BYTE February 1980 199

Listing 1 continued:

1550 INPUT P

1560 ZfI>M>=JfI»fM-l>)*( l + fP/100))

I 570 NEXT I

1580 LET 7.(3,«) = 'JI,«)*Z(2.H)

1590 ZC 10,M> = 0

1 600 EC? 1 = 4 TO 3

1610 LET Z(I0,1)=2(10,M)*Z(I,1«

1620 ZC!l»M>»Z<3*M)-2< 10>M)

1630 NEXT I

1640 INPUT"MO"E PAPER TO TOP OF PAGE AND PRESS A KEY";AS

1650 ? CS : ?

1 660 F0D 1=1 TO 11

1 670 ? NSC 1 >, Z( IjM)

1 68 0 NEXT I :? : ? :? 169C »ETr°N

1700 PEM CALCULATE P°OFORMA WITH IN CLEMEN TAL S

1710 M = N +1

1 720 B = M

1730 FOP 1=1 TO F

1740 ?"AMOUNT OF CHANGE F0» "JNKI)

1750 INPUT P

1760 LET Z(L.«)=ZXJL« fM- m+P

1770 NEXT I

1780 INPUT"MOVE PAPE<? TO TOP OF PAGE 4 PRESS A KEY"; AS

1790 ? CI:?

1 300 FOR I = lTOf

1810 ? N I ( I ) ., 7. ci,~n

1820 NEXT I : ? : ? : ?

18 30 PETL'PN

1840 SVITCFt

1850 ENT

DO YO" M/yuT a LIcT OF C0"1n'A~ATI VE FINANCIAL RATIOS?

PLEASE ANSVE^ YES 0^ WO. THE ALTERNATIVE IS COMPARATIVE -> vr. c

~I9VE' PAPER TO TOP OF PAGE 4 PRESS A KEY?

M1TS RATIO ANALYSIS

RATIOS FOP 2 YEARS BEGINNING IN 1974

CURRENT

1974

.53159

1975

.907047

ACID

1974

.0961952

1975

.301513

RCBL TO

1974

13.6 149

1975

29.1469

INV TD

1974

122. 29 1

1975

1 10.6'52

ASSET TO

1974

1.97689

1975

2. 1609 7

PROF ON SALES

1974

-.223032

1975

.0963033

ROA

1974

-. 4409 09

1975

.203 109

ROI

1974

1.04041

1975

2.03394

EPS

1974

-.237236

1975

. 329392

PAYOUT

1974

0

1975

0

EBT-EOU

1974

1.42373

1975

.900137

r INT EARNED

1974

-6. 1 368

1975

8.80243

BK/SHARE

1974

-.228021

1975

.158062

Listing 1 continued on page 201

use by the firm. This should be high for an income stock and low for a growth stock (all other things being equal).

earnings per share: How much the firm made per share of common stock. Often this and the price/ earnings ratio are the only things investors look at. There are actually two ways of calculating the earnings per share ratio; the more complicated one would require a program much longer than that provided in this article. Both types of earnings per share ratios are required in annual reports, so it is best to rely on both for needed information if a firm has a complicated capital structure.

inventory turnover: The cost of goods sold is divided by average inventory, and this is divided by 365.

profit on sales: Net income divided by net sales. This provides a very conservative estimate of profits. Therefore, it is frequently used when companies wish to appear as though they are not making much of a profit.

quick ratio (acid test): Unlike the current ratio, the quick ratio does not consider inventory and prepaid expenses as current assets. The quick ratio takes cash, marketable securities; and accounts receivable, and divides these by current liabilities. The result is the proportion of liabilities falling due within one year, which can be covered by assets sure to be worth cash. It is normally a little less than one.

return on assets: Net income divided by average total assets. How much you are making on what you have to make it with. As with any profit measure, the higher the better.

return on investment: Net income divided by the quantity assets minus liabilities. This shows how much the firm made on what the owners put into it. Assets which were bought with borrowed money are not included in the base.

times interest earned: The quantity of net income plus interest and tax payments divided by interest charges. This indicates how much more the firm made than was required to pay the interest on its debt. A firm which has a times interest earned ratio of less than one is bankrupt.

200 February 1980 © BYTE Publications lnc

Listing I continued: DO YOU WANT COMPARATIVE % FROM INCOMER STMT i BS? MOVE PACE" TO TOP OF PAGE 4 PRESS A KEY?

YES

INCOME STATEMENT ITEMS AS X OF TOTAL SALES

K INCOME

1974

100

1975

100

OTH REV

1974

0

1975

0

TOT INC

1974

100

1975

100

CGS

1974

52.7711

1975

65. 1867

DEPP

1974

2.08339

1975

1.83227

SGA

1974

34.2403

1975

21.8118

I NT

1974

3.12509

1975

1.23427

TAX

1974

0

1975

0

DIV

1974

0

1975

0

TOTAL EXP

1974

39.5321

1975

25.183

NET INC

1974

-22.3032

1975

9.63033

B.S. ITEMS AS * OF TOTAL ASSETS

CASH

1974

6.3007

1975

7.49898

RCBLS

1974

7.37402

1975

17.2563

INV

1974

54.823

1975

42.7045

PPD ITEMS

1974

6.99943

1975

6.98874

TOT CUR

1974

75.5686

1975

74.4719

LAND

1974

0

1975

0

BLDG/EOU

1974

36.374

1975

31.3656

ACC IL"

1974

1 1 .992

1975

7.95155

TOT FIXED

1974

24. 332

1975

23.4141

0 TH AS

1974

.0494237

1975

2.11405

TOT ASTS

1974

100

1975

100

ACCTS PEL

1974

35.2718

1975

22.1241

NOTES PBL

1974

83.3067

1975

21.4354

CUR LT

1974

1.77143

1975

2.619 7:.

OTHEP LIAB

1974

21.3059

1975

35. 9244

CUR LIAB

1974

142.156

1975

LT DEBT

1974

1975 TOT LIAB

1974

1975 C STK

82.1036

.222407 7.9 1 007

142.378 90.0137

1974

1.85936

1975

. 6318

A PIC

1974

51.6014

1975

19.6497

RE

1974

-95.8391

1975

- 10.2218

TOT CR

1974

100

1975

100

DO YOU WANT TO CREATE A PROFORMA INCOME STATEMENT? YES

DO YOU WANT TO USE * CHANGES FROM LAST PERIOD? YES

CHANGE FOR SALES

? 100

CHANGE FOR OTH REV

? 0

CHANGE FOR TOT INC

? 100

CHANGE FOR CGS

? 50

CHANGE FOR DEPR

? 50

CHANGE FOR SGA

7 50

CHANGE FOR INT

? 50

CHANGE FOR TAX

? 50

CHANGE FOR DIV

? 50

MOVE PAPER TO TOP OF PAGE AND PRESS A KEY?

MITS

SALES

6. 48 1 54E+06

OTH =E<'

0

TOT IMC.

6. 48 1 54E+06

CGS

3. 1 6333E+06

DEPR

91500

SGA

1. 06031E+06

INT

60000

TAX

0

DIV

0

TOTAL EXP

4. 38063E+06

NET INC

2. 1 009 1E+06

DO YOU WANT A 7. ANALYSIS OF THE PROFORMA? YES MOVE PAPER TO TOP OF PAGE * PRESS A KEY?

K INCOME STATEMENT ITEMS AS 7, OF TOTAL INCOME SALES

1976

100

OTH REV

1976

0

TOT INC

1976

100

CGS

1976

48.89

DEPR

1976

1.4117

SGA

1976

16.3538

INT

1976

.925705

TAX

1976

0

DIV

1976

0

TOTAL EXP

1976

67. 5862

NET INC

1976

32.4138

DO YOU WANT

ANOTHER PROFORMA? NO

February 1980 « BYTE Publications Inc 201

Another Plotter to Toy With, Revisited

Design and Construction Details

Robert K Newcomb

502 Washington Ave

Wilmette IL 60091

Following the suggestion of Peter Lucas in the February 1979 issue of BYTE ("Another Plotter to Toy With," page 66) I built a plotter using an Etch-A-Sketch and two stepper motors. After solving the interface problem, I connected it to an I/O (input/output) port on my KIM-1 which is equipped with a teletypewriter, 8 K bytes of extra memory, and Tiny BASIC. Photo 1 shows the result: stepper motors mounted on the EtchA-Sketch, along with a circuit board. The KIM-1 controls the apparatus using 4 bits of an I/O port. The stepper motors can be driven by any other computer having 4 bits of transistor-transistor logic (TTL) level output available.

The Etch-A-Sketch proved to be able to draw bar graphs with excellent results, drawing an even, horizontal baseline, while accurately reproducing data from the computer's memory. I later tried geometric figures, including a parabola. Because each step is only 0.0085 inches (0.216 mm), the device gives good approximations of curves. The main limitation of my plotting system resides in the inability of Tiny BASIC to handle fractional numeric values.

Stepping Motors and Drivers

North American Philips series 82701 stepping motors were chosen for drivers, even though the Etch-ASketch does not require all of the torque that these motors can produce. The extra torque will come in

Photo Is The stepper motor and control assembly is mounted on the Etch-A-Sketch. The knobs have been removed to allow attachment of the driven gears to the shafts.

handy if you later wish to drive something else. The motors are driven by North American Philips (or Signetics) SAA 1027 driver integrated circuits which produce the succession of pulses needed to energize the four windings on each motor. Each driver receives toggling pulses to rotate the motor shaft, while a high or low-level signal on the rotation input determines direction. A single 7406 buffer takes 5 V from the output ports and provides 12 V switching to both

drivers. Figure 1 shows the circuit diagram. Each motor has an output torque of 7 ounce-inches at fifty steps per second and drives the Etch-ASketch through a 5 to 8 reduction gear.

Electrical Construction

A pre-etched and drilled Calectro J4-404 circuit board was used, after I sawed off the ends (to clear the stepper motors) and drilled holes for stand-offs. Two 14-pin integrated cir

202 February 1980 @ BYTE Publications Inc

PAO LZ>

PA I O

>2.2K | ci 7406

^*

+ I2V A

100 ^vw—

rh

+ 5V A

PA20

P«3[>

^

ICI +'2V

7406 *

Number Type

+ 5 V

GND

IC1 7406

11,13,14

7

IC2 SAA1027

5,12

IC3 SAA1027

5,12

J

IC2

SAAI027

SET INPUT

Vl GND

01 Q2 03 04

T

IC 3 SAA 1027

SET INPUT

GND

GND

01

02 03 04

T

150ft I w

+ I2V A

~7h

TI IN400I if if T TYPICAL

i5on

H2V A

"*

;rr

■0>NUMBER 2 GRAY

-C>NUMBER 2 YELLOW

-CZ>NUMBER I GRAY

-0>NUMBER I YELLOW

+ I2V T_

A >NUMBERS I AND 2 RED AND BLACK

I

IN400I YPICAL F 4

-C7J>NIIMBER 2 GRAY

-C7J>NUMBER 2 YELLOW

-f~Z>NUMBER I GRAY

-0>NUMBER I YELLOW

+ I2V

T_

-O NUMBERS I AND 2 RED AND BLACK

Figure 1: Schematic diagram of the stepper motor control and drive circuit. The integrated circuit IC2 controls the X axis; IC3 drives the motor for the Y axis.

cuit sockets were mounted, one for the 7406 buffer and one to receive flat wire connections from the computer. For the 12 V power supply, run a two conductor, #18 cord directly to a fused (IV2 A) unregulated 12 V power supply (18 V maximum peak). Number 22 wire should be used for all other connections. The last step in wiring should be to connect the stepper motors.

Mechanical Construction

The motor frame is a 3/i6 inch (0.476 cm) thick aluminum plate, cut to 2V4 by 11 inch (6.35 by 27.94 cm) dimensions, with the stepping motors mounted on 8V4 inch (20.95 cm) centers to match the Etch-A-Sketch. You must drill clearance holes for the motor shafts (big enough to clear the twenty-tooth gears), and drill for the following items: four holes for circuit board stand-offs, two mounting holes per motor, and two holes at each end for the locating pieces that center the Etch-A-Sketch under the motor

mount. Use of a drill press speeds up this work considerably. These locating pieces are % by 1 by 1% inches (0.95 by 2.54 by 4.76 cm) long and are tapped at the top for two screws each, and at bottom for two screws which hold a Vt by 1 by 11 inch (0.635 by 2.54 by 27.94 cm) clamp piece that keeps the motor mount and Etch-A-Sketch together. Tack or staple two pieces of 3/i6 inch (0.476 cm) outside diameter rubber tubing to a piece of Vi by 1 by 4% inch (1.9 by 2.5 by 12.4 cm) wood to form a cushioned spacer between the motor mount and the Etch-ASketch. This prevents the plastic housing from cracking and spaces the assembly so that the gears line up. The driven gears (thirty-two teeth) are screw clamped to the Etch-ASketch control shafts after the knobs have been pulled off the device. When you slide the Etch-A-Sketch into place, move it until the gears mesh and bottom out against one another, and then slide it back about y32 of

an inch (0.08 cm). Lubricate the gears with a small amount of grease.

Programming

The first programming to be done is a routine which will rotate the stepping motors in the desired direction, one at a time. To move the Etch-ASketch stylus in the +Y (up) direction, output port pin PAl should be set equal to 0 and pin PAO is then toggled. For —Y (movement down), set PAl to 1 and toggle PAO. Movement right and left (+X and —X) works the same way with pin PA3 setting direction. A machine language program which does this, written for the KIM-1, is given in listing 1. Figure 2 gives the flowchart, and listing 2 gives the code for a program to move the stylus along the Y axis according to data in memory, while the stylus moves one unit in the +X direction.

If a series of memory locations contain a value of 0, the stylus will move only horizontally. If a memory location contains a 1, the stylus will move

February 1980 © BYTF Publications Inc 203

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204 February 1980 © BYTE Publications Inc

f START J

OPEN PADD SET UP VEB

ETC

( END J

ARE THE CURRENT AND END ADDRESSES

THE SAME

GET Y

FROM MEMORY

SET DD TO+Y

CHANGE Y TO POSITIVE

-*!•

( END J

SET DD TO

+ X AND TOGGLE

TOGGLE Y IN DD

LOAD PAD FROM DD AND DELAY

LOAD PAD FROM DD AND DELAY

INCREMENT VEB+1, + 2

DECREMENT Y

Figure 2: Flowchart of the routine in listing 2 which moves the stylus along the Y axis according to plot data in memory while maintaining constant movement along the X axis.

up at a 45° angle. To load the plotting data from BASIC, we set up two jumps to machine language subroutines as shown in listing 3. The first subroutine sets up a memory pointer. The second subroutine increments this pointer to load consecutive memory locations each time

the BASIC program calls it. A Tiny BASIC parabola plotting program using these instructions is given as listing 4.

When you set up your programs, it is nice to avoid running off the EtchA-Sketch screen, although no harm will result. Thus you should try not

Listing 1: Routines written in 6502 assembler for the KIM-1 to move the Etch-A-Sketch stylus along a single axis by individually activating the stepper motors.

Hexadecima

Address

i Code

3A40

A9 0F

3A42

8D01 17

3A45

60

3B1C

A0 FF

3B1E

A2 20

3B20

CA

3B21

DOFD

3B23

88

3B24

D0F8

3B26

A5 DE

3B28

AA

3B29

A5 DF

3B2B

A8

3B2C

60

3A46

20 40 3A

3A49

A9 01

3A4B

8D00 17

3A4E

20 1C3B

3A51

A9 00

3A53

8D0O 17

3A56

20 1C3B

3A59

4C 49 3A

3A66

20 40 3A

3A69

A9 03

3A6B

8D00 17

3A6E

20 1C3B

3A71

A9 02

3A73

8D00 17

3A76

20 1C3B

3A79

4C 69 3A

3A86

20 40 3A

3A89

A9 04

3A8B

8D00 17

3A8E

20 1C3B

3A91

A9 00

3A93

8D00 17

3A96

20 1C3B

3A99

4C 89 3A

3AA6

20 40 3A

3AA9

A9 0C

3AAB

8D00 17

3AAE

20 1C3B

3AB1

A9 08

3AB3

8DO0 17

3AB6

20 1C3B

3AB9

4C A9 3A

Label

SPEED

Op Code

Mnemonic

Operar

LDAIM

$000F

STA

PADD

RTS

LDYIM

$00FF

LDXIM

$0020

DEX

BNE

$3B20

DEY

BNE

S3B1E

LDAZ

$00DE

TAX

LDAZ

$00DF

TAY

RTS

JSR

$3A40

LDAIM

$0001

STA

PAD

JSR

SPEED

LDAIM

$00

STA

PAD

JSR

SPEED

JMP

$3A49

JSR

$3A40

LDAIM

$0003

STA

PAD

JSR

SPEED

LDAIM

$0002

STA

PAD

JSR

SPEED

JMP

$3A69

JSR

$3A40

LDAIM

$0004

STA

PAD

JSR

SPEED

LDAIM

$00

STA

PAD

JSR

SPEED

JMP

$3A89

JSR

$3A40

LDAIM

$000C

STA

PAD

JSR

SPEED

LDAIM

$0008

STA

PAD

JSR

SPEED

JMP

S3AA9

Commentary

SUBROUTINE TO OPEN PADD

SUBROUTINE TO SET SPEED

DECREMENT X, LOOP IF NOT 0 DECREMENT Y, LOOP IF NOT 0

RESTORE X AND Y

MOVES STYLUS IN PLUS Y DIRECTION UNTIL INTERRUPTED SET Y ROTATION OFF, Y TRIGGER ON DELAY APPROPRIATELY

SET Y TRIGGER OFF

MOVES STYLUS IN MINUS Y DIRECTION

UNTIL INTERRUPTED

SET Y ROTATION ON, Y TRIGGER ON

MOVES STYLUS IN PLUS X DIRECTION UNTIL INTERRUPTED SET X ROTATION OFF, X TRIGGER ON

MOVES STYLUS IN MINUS X DIRECTION UNTIL INTERRUPTED SET X ROTATION ON, X TRIGGER ON

Listing 2: Program written for the KIM-1 which moves the stylus along the X axis at a constant rate while movement along the Y axis is varied according to plot data stored in memory.

Hexadecimal

Op Code

Address

Code

Label

Mnemonic

Operand

Commentary

3B11

A5 DD

LODPAD

LDAZ

$00DD

THIS ADDS LOADING OF THE

3B13

8D00 17

STA

PAD

OUTPUT PORT TO THE TIMING

3B16

8A

TXA

SUBROUTINE OF LISTING 1

3B17

85 DE

STAZ

$00DE

3B19

98

TYA

3B1A

85 DF

STAZ

$00DF

3B30

A9 0F

LDAIM

$000F

THIS IS THE PROGRAM SHOWN

3B32

8D01 17

STA

PADD

IN FIGURE 2. ZERO PAGE

3B35

ADF5 17

LDA

SAL

LOCATIONS CC THROUGH CF ARE

3B38

85 CC

STAZ

CURADL

VECTOR EB. LOCATION DD

3B3A

ADF6 17

LDA

SAHI

IS STORAGE FOR PORT A DATA

3B3D

85 CD

STAZ

CURADH

3B3F

A9 AD

LDAIM

$00AD

3B41

85 CB

STAZ

GETY

3B43

A9 A8

LDAIM

S00A8

3B45

85 CE

STAZ

$00CE

3B47

A9 60

LDAIM

$0060

3B49

85 CF

STAZ

$00CF

3B4B

A5CC

COMEND

LDAZ

CURADL

COMPARE VEB + 1, VEB + 2 WITH

3B4D

CDF7 17

CMP

ENDALO

END ADDRESS Listing 2 con.

'imied on page 206

February 1980 © BYTE Publications Inc 205

Listing

2 continued:

3B50

A5CD

3B52

EDF8 17

3B55

BO 43

3B57

20 CB 00

3B5A

10 OE

3B5C

A9 02

3B5E

05 DD

3B60

85 DD

3B62

98

3B63

49 FF

3B65

A8

3B66

C8

3B67

4C70 3B

3B6A

A9 FD

3B6C

25 DD

3B6E

85 DD

3B70

98

3B71

30 27

3B73

FOOD

3B75

A9 01

3B77

45 DD

3B79

85 DD

3B7B

20 11 3B

3B7E

88

3B7F

4C 70 3B

3B82

A9 07

3B84

25 DD

3B86

85 DD

3B88

A9 04

3B8A

45 DD

3B8C

85 DD

3B8E

20 11 3B

3B91

E6 CC

3B93

DO 02

3B95

E6CD

3B97

4C4B3B

3B9A

00

YPLUS

MITOPL

SET PLS

YMINUS

TOGY

TOGX

END

LDAZ

SBC

BCS

JSR

BPL

LDAIM

ORAZ

STAZ

TYA

EORIM

TAY

INY

JMP

LDAIM

ANDZ

STAZ

TYA

BMI

BEQ

LDAIM

EORZ

STAZ

JSR

DEY

JMP

LDAIM

ANDZ

STAZ

LDAIM

EORZ

STAZ

JSR

INCZ

BNE

INCZ

JMP

BRK

CURADH

ENDAHI

END

GETY

SETPLS

$0002

SOODD

$00 DD

$00FF

YMINUS $00FD $00DD $00DD

END

$3B82

$0001

$00DD

$00DD

LODPAD

YMINUS

$0007

$00DD

$00DD

$0004

$00DD

$00 DD

LODPAD

CURADL

S3B97

CURADH

COMEND

TO END IF ADDRESSES MATCH Y POSITIVE

SET ROTATION IN DD FOR - Y CHANGE -YTO +Y

JUMP PAST SET PLUS ROTATION SET Y ROTATION FOR PLUS

Y IS STILL MINUS, END ROUTINE

Y =0, BRANCH TOGGLE Y IN DD

LOAD PAD FROM DD AND DELAY DECREMENT Y

JUMP BACK TO SECOND "IS Y MINUS' SET DD TO PLUS X

TOGGLE X IN DD

LOAD PAD FROM DD AND DELAY INCREMENT VEB+1

INCREMENT VEB +2

REPEAT

END

Listing 3: Machine language subroutines which are called from the Tiny BASIC program of listing 4. The first routine sets up a memory pointer. The second routine increments the pointer to load consecutive memory locations each time the BASIC program

calls it.

Hexadecimal

Address

Code

1780

A9 8D

1782

85 DA

1784

A9 00

1786

85 DB

1788

A9 02

178A

85 DC

178C

A9 60

178E

85 DD

1790

60

1791

20 DA00

1794

E6 DB

1796

DO 02

1798

E6 DC

179A

60

Label

Op Code

Mnemonic

Operand

Commentary

LDAIM

$008 D

SET UP MEMORY POINTER WITH

STAZ

$00DA

MEMORY STARTING ADDRESS

LDAIM

$00

SET LOW STARTING ADDRESS

STAZ

SUBPAD

LDAIM

$0002

SET HIGH STARTING ADDRESS

STAZ

$00DC

STARTING ADDRESS DEFAULT

LDAIM

$0060

IS 0200.

STAZ

$00 DD

RTS

RETURN

JSR

$00DA

LOAD MEMORY WITH CONTENTS

INCZ

SUBPAD

OF ACCUMULATOR

BNE

$179A

INCZ

$00DC

INCREMENT MEMORY POINTER

RTS

RETURN

Listing 4: Program written for the KIM-1 in Tiny BASIC to plot a parabola using the machine language routines of listing 3.

100 LET N = USR (6016)

105 REM THIS IS 1780 HEXADECIMAL

110 LETC = -120*120/10

120 LET A = -119

130 LETB = A*A/10

140 LETD = B-C

150 LETC=B

160 IFD= -2 THEN LET D= -3

190 IF D = 2 THEN LET D = 3

200 LET D = D/3

210 LET N = USR(6033,0,D)

215 REM THIS EQUALS 1791 HEXADECIMAL

216 REM SUBROUTINE IS ENTERED WITH D IN ACCUMULATOR 220 LETA = A+1

230 IF A> 120 GOTO 250

240 GOTO 130

250 END

206 February 1980 S) BYTE Publications Inc

Parts List

2 gears: Sterling S1268ZS20AP1 (32 pitch, 32 teeth) or equivalent

2 hubs: Sterling E62-4 (3/16 inch bore for above) or equivalent

2 gears: Sterling S1086ZH2920P1 (32 pitch, 20 teeth, Vt inch bore) or equivalent

2 stepper motors: North American Philips Controls Corp K82701P2

2 stepper motor driver integrated circuits: Signetics SAA1027

1 circuit board: Calectro J4-404

Miscellaneous sheet aluminum and screws, wood block, and rubber tubing.

A limited quantity of kits of the above items (ready to assemble with no cutting or drilling necessary) are available from the author for $109 postpaid, plus tax for Illinois residents.

The following items are stocked by most electronic distributors:

2 16-pin soldertail integrated circuit sockets 2 14-pin soldertail integrated circuit sockets

1 type 7406 integrated circuit hex inverting driver 4 2.2K ohm V* W resistors

4 12K ohm V* W resistors

2 100 ohm Vi W resistors 2 150 ohm 1 W resistors 2 0.1 /jF 36 V capacitors 8 1N4001 rectifier diodes 1 0.001 nF 16 V capacitor

to use more than 790 (decimal) memory locations in the program of listing 3. The total of all negative or positive numbers in the parabola plotting program of listing 4 should be less than decimal 558.

The stepper drivers generate some electrical noise. I have no trouble with BASIC crashing, provided that the 12 V supply is off. For cassette recording, both 12 V and 5 V supplies should be off. For playback, both supplies can be on. Before disconnecting the I/O ports from the Etch-ASketch, push reset (RS) to switch the ports to their high impedance position. This eliminates the possibility of destroying the 7406 buffer device.

Once you have loaded the program into memory and have stored it on a cassette, plug the connections from the 7406 buffer into your computer and turn on the 12 V supply (with the lVz A fuse in place). Using the monitor, execute the appropriate subroutines from listing 1 to move the stylus to the desired origin (typically upper left). Starting execution at hexadecimal location 3B30 will plot whatever data is contained in memory.

With experience in programming, you can set up a grid against which plotting can be done. The fine line produced by the Etch-A-Sketch makes measuring easy. Two advantages of the Etch-A-Sketch are that you don't use any memory preserving information on the screen, and the device is completely nonvolatile.

Begin a plot today, shut down your system before finishing, and weeks later you can come back and continue the plot. You will also experience the

satisfaction of watching your computer move things in the real world, rather than manipulate shadows on a television screen. ■

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February 1980 IS BYTE Publications Inc 207

Circle 161 on inquiry card.

DEFINITELY DIFFERENT.

FROM HAYDEN

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Available at your local computer store.

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50 Essex Street, Rochelle Park, NJ 07662

208 February 1980 © BYTE Publications Inc

BYTE's Bits

Personal Computers for the Handicapped

The Applied Physics Laboratory of Johns Hopkins University is the location of a project being organized by Paul L Hazan. This project is a program for the application of personal computers to the problems of people with various physical handicaps.

Various applications include simple computercontrolled communications aids for quadriplegics, interfaces between computers that allow hearing-impaired individuals to communicate via telephone, and other very inexpensive applications of off-the-shelf hardware. A design contest with substantial prizes is being considered.

Those interested in more details may contact Paul L Hazan, Assistant to the Director for Advanced Computer Technology, Johns Hopkins University, Applied Physics Laboratory, Johns Hopkins Rd, Laurel MD 20810. ■

BYTE's Bugs

Chess Moves Rechecked

Thanks to John Gropper for pointing out an error in "Alpha-Beta Pruning," by W D Maurer (November 1979 BYTE, page 84). Figure 1 gives white's second move as Q-N7. The correct move is Q-N8. The move is shown correctly in figure 2.B

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Features 4 MHz CPU, 64K of RAM, dual-sided PerSci 299B floppy disk drive (provision for installing a second 299B), RS232C interface, printer interface. All Cromemco systems are assembled and tested, ready to use. With 64K of RAM, List $6585 .... ONLY $5485 — NOW DOUBLE THE CAPACITY! —

CROMEMCO SYSTEM 2

With 64K of RAM, two minifloppy disk drives, RS232 interface and printer interface board. System 2 w/64K RAM, List $3990 $3390

Z-2 COMPUTER SYSTEM - can

be rack mounted. Z-80 processor, 21 slots, power supply, front cover panel. Includes fan and all edge connectors. Assembled and tested. CRO-10000-A (Z-2W), List $995 $845

Z-2D DISK COMPUTER similar

to Z-2 but comes with floppy disk controller, DOS, and minifloppy disk drive. A complete system with the addition of a RAM board. CRO-10020-A (D2D-W), List $1990 $1689

CROMEMCO BOARDS

CRO-31010-A (SCC-W) 4 MHz Single Card Computer, Assem./tested, List $450 .... $382 CRO-310001-K (ZPU-K) 4 MHz CPU card. Kit 250 CRO-31000-A (ZPU-W) Above, assembled . 335 CRO-32020-A (16KZ-W) 16K RAM card with bank select, assem./tested, List $595 .... 495

SHIPPING, HANDLING 6 INSURANCE: Add $2 lor boards Assembled systems shipped freight collect. All prices subiect to change and all offers subject to withdrawal without notice. Above prices are for prepaid orders Slightly higher prices prevail for other-than-prepaid orders

WRITE FOR FREE CATALOG P

MiniMicroMait

1618 James St., Syracuse NY 13203 (315) 422-6666 TWX 710-541 -0431

Circle 162 on inquiry card.

A

iTi

I

LIBRARY...

with a complete a

PAPERBYTE and

YOU JUST BOUGHT A PERSONAL WHAT is filled with practical ideas for using a personal computer at home or work. It will take you through the steps necessary to write your own computer programs, and then show you how to use structured design techniques to tackle a variety of larger projects. The book contains over 60 ready-to-use programs written in Radio Shack TRS-80 Level II BASIC in the areas of educational games, financial record keeping, business transactions, disk-based data file and word processing.

ISBN 0-07-018492-5

Authors: Thomas Dwyer and Margot Critchfield

Pages: 256 Price: $11.95

BEGINNER'S GUIDE FOR THE UCSD PASCAL SYSTEM is written by the originator of the UCSD Pascal System. This highly informative book is designed as an orientation guide for learning to use the UCSD Pascal System. Once familiar with the system, you will find the guide an invaluable reference tool for creating advanced applications. This book features tutorial examples of programming tasks in the form of selfstudy quiz programs.

ISBN 0-07-006745-7

Author: Kenneth Bowles

Pages: 184 Price: $11.95

PAPERBYTE BOOKS are BYTE BOOKS with bar codes included!

SUPERWUMPUS is an exciting computer game incorporating the original structure of the WUMPUS game along with added features to make it even more fascinating. Programmed in both 6800 assembly language and BASIC, SUPERWUMPUS is not only addictively fun, but also provides a splendid tutorial on setting up unusual data structures. This is a PAPERBYTE® book.

ISBN 0-07-019342-8

Author: Jack Emmerichs

Pages: 56 Price: $6.00

TINY ASSEMBLER 6800: Version 3.1 has an updated version of the user's guide, the source, object and PAPER

BYTE® bar code formats of both Version 3.0 and 3.1. This book is the most complete documentation possible for Jack Emmerichs' Tiny Assembler.

ISBN 0-07-019341-X

Author: Jack Emmerichs

Pages: 80 Price: $9.00

RA6800ML: AN M6800 RELOCATABLE MACRO ASSEMBLER provides the necessary background for coding programs in the 6800 assembly language, and for understanding the innermost operations of the Assembler. The PAPERBYTE® bar code representation of the Assembler's relocatable object file is included.

ISBN 0-07-028056-8 Author: Jack E. Hemenway Pages: 184 Price: $25.00

LINK68: AN M6800 LINKING LOADER provides everything necessary for the user to easily learn about the system. In addition to the source code and PAPERBYTE® bar code listings, there is a detailed description of the major routines of the Linking Loader, including flowcharts. ISBN 0-07-024120-1 Authors: Robert D. Grappel

& Jack E. Hemenway Pages: 72 Price: $8.00

BASEX, a new compact, compiled language for microcomputers, has many of the best features of BASIC and the 8080 assembly language — and it can be run on any of the 8080 style microprocessors: 8080, Z-80, or 8085. Subroutines in the BASEX operating system typically execute programs up to five times faster than equivalent programs in a BASIC interpreter — while requiring only about half the memory space. The author, Paul Warme, has also included a BASEX loader program which is capable of relocating programs anywhere in memory. This is a PAPERBYTE® book.

ISBN 0-07-068290-9

Author: Paul Warme

Pages: 88 Price: $8.00

TRACER: A 6800 DEBUGGING PROGRAM includes a reprint of "Jack and the Machine Debug" (from the December 1977 issue of BYTE

magazine), TRACER program notes, complete assembly and source listing in 6800 assembly language, object program listing, and machine readable PAPERBYTE® bar codes of the object code. ISBN 0-07-024121-X Authors: Robert D. Grappel

& Jack E. Hemenway Pages: 24 Price: $6.00

MONDEB: AN ADVANCED M6800 MONITOR-DEBUGGER features ease of use and minimum memory requirements while retaining maximum versatility. The result is an extremely versatile program. The size of the entire MONDEB is less then 3K. This is a PAPERBYTE® book.

ISBN 0-07-049556-4

Author: Don Peters

Pages: 88 Price: $5.00

BAR CODE LOADER contains the general bar code loader algorithm description in flowchart form plus detailed assemblies of program code for 6800, 6502, and 8080 processors. Individuals with computers based on these processors can use the software directly. Individuals with other processors can use the provided functional specifications and detail examples to create equivalent programs. This is a PAPERBYTE® book.

ISBN 0-07-008856-X

Author: Ken Budnick

Pages: 32

Price: $2.00

K2FDOS: A FLOPPY DISK OPERATING SYSTEM FOR THE 8080. K2FDOS is a complete software package and includes all the information and specific routines necessary to bootstrap and run a powerful floppy disk operating system on an 8080-based microcomputer. This small (4K), but powerful, system includes many of the file handling features of large operating systems. It comes complete with source code listings in the hexadecimal format, and machine readable (PAPERBYTE® ) bar code format listings for individual K2FDOS programs.

ISBN 0-07-069206-8

Author: Kenneth B. Welles

Pages: 192

Price: $20.00

ssortment of

BYTE BOOKS !

The following BYTE BOOKS are collections of favorite articles from past issues of BYTE magazine, plus new material.

THE BYTE BOOK OF COMPUTER

MUSIC combines the best computer music articles from past issues of BYTE magazine with exciting new material — all written for the computer experimenter interested in this fascinating field.

An ardent do-it-yourselfer or armchair musicologist will find this book to be a useful addition to the library.

ISBN 0-07-043097-7

Editor: Christopher P. Morgan

Pages: 144 Price: $10.00

CIARCIA'S CIRCUIT CELLAR offers a detailed look at the marvelous projects which let you do useful things with your microcomputer. Each article is a complete tutorial. Using amusing anecdotes to introduce the articles and an easy-going style, Steve presents each project so that even a neophyte need not be afraid to try it.

ISBN 0-07-010960-5

Author: Steve Garcia

Pages: 128 Price: $8.00

THE BYTE BOOK OF PASCAL is a

general introduction to Pascal and contains numerous articles, language forums and letters from past issues of BYTE magazine. In addition, this book contains several important pieces of software including two versions of a Pascal compiler - one written in BASIC and the other in 8080 assembly language; a p-code interpreter written in both Pascal and 8080 assembly languages; a chess playing program; and an APL interpreter written in Pascal.

ISBN 0-07-037823-1

Editor: Blaise W. Liffick

Pages: 342 Hardcover Price: $25

PROGRAMMING TECHNIQUES is

a series of collected articles concerned with the art and science of computer programming. The first volume in the Programming Techniques series is entitled PROGRAM DESIGN. The purpose of the book is to provide the personal computer user with the techniques needed to design efficient, effective, maintainable programs.

ISBN 0-07-037825-8

Editor: Blaise W. Liffick

Pages: 96 Price: $6.00

SIMULATION is the second volume in the Programming Techniques series. Both theoretical and practical applications are included. Particularly stressed is simulation of motion, in

cluding wave motion and flying objects, and the use of simulation for experimentation.

ISBN 0-07-037826-6

Editor: Blaise W. Liffick

Pages: 126 Price: $6.00

NUMBERS IN THEORY AND

PRACTICE is the third book in the series. It includes information of value to both the novice and the experienced personal computer user. The mechanics of the binary system are discussed, including software division and multiplication, as well as floating point numbers, numerical methods, random numbers, and the mathematics of computer graphics.

ISBN 0-07-037827-4

Editor: Blaise W. Liffick

Pages: 192 Price: $8.95

BITS & PIECES is the fourth volume in the Programming Techniques series. It covers various topics of interest to programmers. It is a collection of the best articles from past issues of BYTE magazine plus new material collected specifically for the series, on subjects such as multiprogramming, stacks, interrupts, optimization, and real-time processing.

ISBN 0-07-037828-2

Editor: Blaise W. Liffick

Pages: 160 Price: $8.95

(available Spring '80)

m

Circle 163 on inquiry card.

Pl

ease send

Name

Title

Company

Street

City

State/Province

Code

□ Check enclosed in the amount of $

□ Bill Visa □ Bill Master Charge Card No. Exp. Date.

Add 60<t per book to cover postage and handling.

BITE

.BBLIMS.

70 Main Street,

Peterborough, New Hampshire 03458

. copies of Superwumpus

. copies of Tiny Assembler 6800

. copies of RA6800ML: An M6800 Relocatable

Macro Assembler . copies of LINK68: An M6800 Linking Loader . copies of BASEX

. copies of TRACER: A 6800 Debugging Program . copies of MONDEB: An Advanced M6800

Monitor-Debugger . copies of You Just Bought a Personal What? . copies of Beginner's Guide for the UCSD

Pascal System . copies of Bar Code Loader . copies of K2FDOS: A Floppy Disk Operating

System for the 8080 . copies of The BYTE Book of Computer Music . copies of Ciarcia's Circuit Cellar . copies of The BYTE Book of Pascal . copies of Program Design . copies of Simulation

. copies of Numbers in Theory and Practice . copies of Bits & Pieces

WhsftNew?

PERIPHERALS

90 M Byte Disk Subsystem

The model AM 410 90 M byte (formatted) disk subsystem is based on the CDC Phoenix drive. The unit consists of 75 bytes of fixed disk capacity combined with 15 M bytes of removable cartridge. The controller is interrupt driven and operates on full 512-byte sector data transfers. The AM 410 has an average access time of 30 milliseconds and provides full cyclic redundancy check (CRC) and sentinel bit error checking capabilities. Up to four drives can be connected to one controller for a total storage capacity of 360 M bytes of data. The AM 410 is designed to work with Alpha Micro's AMOS operating system and other operating systems on either the 8- or the 16-bit S-100 bus. The selfcontained unit is available from Alpha Micro, 17881 Sky Park N,. Irvine CA 92714, for under $15,000.

Circle 451 on inquiry card.

Printers and Plotters for the Apple II, PET, TRS-80

Axiom Corp, 5932 San Fernando Rd, Glendale CA 91202, has introduced the EX-801 and EX-820 series printers and plotters for the Apple II, PET, and TRS-80. Each printer can be plugged into the different microcomputers without any special user adaptation.

The EX-801 features the full 96-character ASCII set, 80 characters per line, 80 columns, and full user control of individual dots in graphics mode.

The EX-820 includes all the features of the EX-801 plus the capability of being a full plotter that can generate schematics, musical scores, charts and other displays. The EX-820 can print any graphics image with up to 128 dots per inch resolution.

The price for the EX-801 is $535. Circle 452 on inquiry card.

The Sorcerer's Voice

The model SV-100 is a self-contained device that generates tones, musical notes, and sound effects. The unit plugs into the parallel output port of the Sorcerer and features a built-in speaker. The SV-100 utilizes twenty-one tones including twelve musical notes. A cassette includes an INTRO for the SV-100; SDEFT, a sound effects program; MUSIC, a real-time music composition program; and HORSE, a horse race game with sound effects.

The SV-100 is available from Indiana Digital Corp, POB 3755, South Bend IN 46619, for $49.95.

Circle 453 on inquiry card.

100% Error Free Floppy Disks

DVSAN

MINI DISKETTES

Error free single- and double-sided 5-inch floppy disks in 35- or 40-track versions are available from Dysan Corp, 5440 Patrick Henry Dr, Santa Clara CA 95050. They are available in hard- or soft-sectored versions.

Circle 454 on inquiry card.

Standard Letter-Quality, Wide Carriage Printer

The CPT Rotary V is an up to 40 character per second (cps) serial printer with letter-quality printout, a metal daisy print wheel, and the printer can be used with the CPT 6000 and 8000 word processing systems. Featured are an adjustable platen for multiple part forms, ribbon lift for position accuracy, and bidirectional paper feed for forms fill-in applications. The Rotary V is priced at $4000 and is available from CPT Corp, 1001 2nd St S, Hopkins MN 55343.

Circle 455 on inquiry card.

Universal Graphics Display Peripheral

The G-Box is a peripheral device which can be used with any computer to add high-density graphics. The video image output is a matrix of 512 by 240 dots with an expansion capability. Connection to the computer is through an RS-232 serial link. The G-Box accepts standard ASCII codes and it does not require assembly language routines. It can be controlled from BASIC and other languages. Interfaces for joysticks, serial and parallel ports, a light pen interface, and other options are built into the unit. The G-Box can be adapted to work on the TRS-80, Heath, Commodore, North Star, and other microcomputers. Prices range from approximately $350 for the primary version (without cabinet), up to over $2000 for terminal units with full options. Contact Objective Design Inc, POB 20325, Tallahassee FL 32304. Circle 456 on inquiry card.

Where Do New Products Items Come From?

The information printed in the new products pages of BYTE is obtained from "new product" or "press release" copy sent by the promoters of new products. If in our judgment the information miglit be of interest to the personal computing experimenters and homebrewers who read BYTE, we print it in some form. We openly solicit releases and photos from manufacturers and suppliers to this marketplace. The information is printed more or less as a first in first out queue, subject to occasional priority modifications. While we would not knowingly print untrue or inaccurate data, or data from unreliable companies, our capacity to evaluate the products and companies appearing in the "What's New?" feature is necessarily limited. We therefore cannot be responsible for product quality or company performance.

212 February 1980 © BYTE Publications Inc

SOFTWARE and PERIPHERALS

IBM to CP/M or CP/M to IBM Transfer Utility Program

The IBM2CPM program uses an IBM or equivalent mainframe to develop systems for microcomputers using crosscompilers and assemblers. The resulting source programs are transferred to the microcomputer via a standard 8-inch floppy disk. This system enables a microcomputer to act as a data entry system for a large mainframe. The program features interactive operation that allows users to specify which files to copy, the ability to display the directory on an IBM standard interchange floppy disk, and more. IBM2CPM is available from Precision Computer Systems Inc, 1737 N First St, San Jose CA 95112 for $95.

Circle 457 on inquiry card.

Bus(iness) 1

Designed for SwTPC 6800 and PET systems, this package contains thirty programs, including payroll, cash flow, profit and loss accounting, stock control, invoices, sales ledger, updating address files, and more. The package can run up to four companies, eight bank accounts, fifty agents, 999 customers or suppliers, 1000 stock items and two-hundred employees, depending on disk storage. The program can run in 20 K bytes of memory and has been adapted to the 6502 processor. It costs $275 plus value added tax (VAT). For more information, contact G W Computers Ltd, 89 Bedford Court Mansions, Bedford Ave, London WCl ENGLAND. Circle 458 on inquiry card.

Software Protection for S-100 Bus Systems

International Product Development Inc, 1708 Stierlin Rd, Mountain View CA 94043, has developed the LW100 board that operates with standard software, as well as protected software that can be copied for a user's computer. Each LW100 board contains a key that is different from all other boards. The protected software has a key lock programmed to work with only one computer. Manufacturers and software houses that wish to protect their software would supply the customer with a LWI00 board and protected software. Future sales to that cutomer require only the protected software that works with the customer's keyed computer. The cost for the board is 5139.

Circle 459 on inquiry card.

WIZRD Multitasking Disk Operating System

Wintek's system includes true deviceindependent (virtual) input/output (I/O); HEAP memory management for efficient memory allocation for I/O buffers; and command indirection, which allows commands to be read from files with no operator intervention. It is helpful for systems used by untrained operators. WIZRD is included with Wintek's 48 K, dual-drive SPRINT 68 microcomputer for $3995, or alone for $495. For information, contact Wintek Corp, 1801 South St, Lafayette IN 47904.

Circle 460 on inquiry card.

Word Processor for Apple II and Apple II Plus Systems

Super-Text is a multiple paging system that allows users to view two texl screens simultaneously, keep notes or instructions on one text screen and edit on the other. It features full floating cursor and cursor control; insertion and deletion of characters, words or lines; tabbing; justification; full scrolling; movement to the last change made in the text; global search and replace; block operations; and advanced file handling and print controls. The system runs in 48 K bytes of memory and costs $99.95. It is available from Muse Co, 7112 Darlington Dr, Baltimore MD 21234.

Circle 461 on inquiry card.

Text Formatter for UCSD Pascal Systems

Using the Moonshadow Text Formatter, documents produced with the screen editor are post-processed to provide underlining, automatic pagination, and other essential text-processing functions. It takes standard Pascal text files, operates on them, and sends fully formatted text output to the console display, a printer, or a disk file. Moonshadow Text Formatter provides a full range of formatting functions, plus advanced features such as combining of files into one document, variables in text (for form letters), and output character translation (for printers using nonstandard character sets).

The program is written in UCSD Pascal and works on systems using either North Star 5-inch floppy disks or IBM format 8-inch floppy disks. It is available from Merrimack Systems, POB 5218, Redwood City CA 94063, for $99. Circle 462 on inquiry card.

APL for the 8080, 8085, and Z80

Softronics APL has most of the functions and operators of full APL, including n-dimensional inner and outer product, reduction, compression, general transpose, reversal, take, drop, execute and format, system functions and variables, and system commands. It runs under the CP/M operating system, residing in 30 K bytes of memory. In addition to standard ASCII mnemonic representations, it supports typewriter and bit-pairing ASCITAPL character sets. The shared variable mechanism allows CP/M disk input and output. Softronics APL comes with an optional driver program for video display with programmable character generator. It is priced at $350 on disk, with a user's manual. For more information, contact Softronics, 36 Homestead Ln, Roosevelt NJ 08555.

Double-Sided Dual Disk Drive

The Micro Squared M-250 unit is capable of single or double density and consists of two double-sided drives, a power supply, cable, and chassis. It has 140 tracks, with a capacity of 358 K bytes of memory. The double-density feature allows 875 K bytes of memory storage. The unit also features a write protect sensor, time erase timing circuits internal to the disk drive, and has a sensor that stops the spindle drive motor rotation when no disk is installed. The unit costs $1195 and is available from Micro Squared Inc, Suite 5B, 7131 Owensmouth Ave, Canoga Park CA 91303.

Circle 463 on inquiry card.

Pertec Introduces 8-Inch, 20 M Byte Winchester Drive

This new drive will use a limited motion, 50 ms average access rotary positioner. The Mini-VVini can perform diagnostic routines without the help of the central processing unit by creating a bidirectional bus interface using a 6801 microprocessor. The Mini-Wini has the same physical dimensions, mounting scheme and voltage requirements as floppy disk drives, but offers more storage space than floppy disks. The price is $3000 and is available from Pertec Computer Corp, 9600 Irondale, Chatsworth CA 91311.

Circle 464 on inquiry card.

February 1980 © BYTE Publications Inc 213

What's New?

SOFTWARE

North Star List Processor

HELPB5 is a collection of subroutines which use dynamic memory assignment to perform list processing. The user can create a sequential set of array elements which describe objects. By filing sets on and removing sets from various lists, complex processes can be simulated. Available subroutines include Create, Destroy, File First, File Last, File Ranked—which places an entity on a sorted list based on the value of a selected array element—Remove First, Remove Last, and Remove. Four debug

ging routines allow the user to print all the objects on a list, determine if a particular object is on a specified list, if an array element has a specified value, and print the array elements for a particular entity.

HELPB5 is written in North Star BASIC and needs a minimum of 32 K bytes of programmable memory. The price is $48, including a user's manual and sample simulation program. Contact American Planning Corp, 4600 Duke St, Suite 425, Alexandria VA 22304. Circle 465 on inquiry card.

NEVADA COBOL for Microcomputers

NEVADA COBOL translates source language programs into machine language on 8080, Z80 and 8085 microprocessors. Designed for small businesses using microcomputers, it features random access file support; sequential files, both fixed and variable length; debugging capability; copy statement; character string, 16-bit binary and packed decimal (COMP-3); 18-bit accuracy; hexadecimal non-numeric

literals; and an interactive ACCEPT/DISPLAY. The compiler, which is a subset of ANSI-74, generates programs at a rate up to 650 lines per minute on an 8080-based system. Operating under Processor Technology's operating system (PTDOS), the compiler requires a minimum of 32 K bytes of programmable memory. The NEVADA COBOL Programmers Reference Manual is available for $25 and the Diskette is $275, from Ellis Computing, 1480 17th Ave, San Francisco CA 94122.

Circle 466 on inquiry card.

Library Cross-Reference for Floppy Disks

The CATALOG system provides a means to index up to 200 single- or double-density 5-inch floppy disks. Using the alphabetical lists of files produced by CATALOG, any program or data file can be located in a few seconds. The name, extension, size, date and disk number for each file is listed in each of three reports. These reports are organized by the date within extension within name, extension within name within disk number, and date within

name within extension. A list of disks is provided after each use of the CATALOG program. The program runs on 8080 or Z80 microprocessors with 48 K bytes of memory, floppy disk, video display and printer. The program requires CP/M with Microsoft MBASIC or MITS/Pertec Disk Extended BASIC. The SORT System is required for use of CATALOG. The CATALOG System is priced at $95 and is available from the Software Store Ltd, 706 Chippewa Sq, Marquette MI 49855.

Circle 467 on inquiry card.

6809 Systems Software

Technical Systems Consultants Inc, POB 2574, W Lafayette IN 47906, has developed software which includes a 6809 version of the popular FLEX disk operating system, a text editor, a resident assembler, BASIC interpreter, and an assembly language debug package. Most software written for 6800 FLEX can be reassembled for 6809 by changing any equates into FLEX to the proper addresses. FLEX features dynamic file allocation, random and sequential files, printer spooling, batch job type program entry, automatic space compression, user start-up facility, and English error

messages. The resident 6809 assembler accepts 6809, 6800, and 6801 mnemonics so that existing software can be immediately reassembled to produce 6809 object code.

FLEX is available for the SwTPC disk systems on a 5- or 8-inch floppy disk. The other software is available on a standard 5- or 8-inch FLEX disk which may be used on any soft-sectored 6809 FLEX disk system. Cassette versions are available for all but FLEX. Including the text editor and assembler, the FLEX package is $90. The BASIC interpreter is $65, and the debug package is $75. Circle 468 on inquiry card.

Six Software Programs for Apple Users

These six programs from Williamsville Publishing require an Apple II with 32 K bytes of programmable memory, one disk drive, Disk II, Applesoft II in read-only memory (ROM) on a firmware card. The programs include Book Library; Record Library; Malum II...Imperial Roman Programmable Computer By Command of Caesar, which takes the Latin equivalent of BASIC commands and uses Roman numerals for numeric input and output; Graphics Game; Checkbook Program; and Page Processor.

Individual disks sell for $19.95 from Williamsville Publishing Co, POB 250, Fredonia NY 14063.

Circle 469 on inquiry card.

Software for Radio and Television Stations

Solar Computer Systems Corp, 2360 43rd Ave E, Suite 308, Seattle WA 98112, has a series of software programs designed to run on Smoke Signal Broadcasting's Chieftan Systems that are of interest to radio and television stations. Available programs include audience measurement, attitude research, music research, lifestyle surveys, ARBITRON analyses and more. Information is available upon request.

Circle 470 on inquiry card.

Math Program Performs Symbolic Operations for Algebra, Trigonometry, and Calculus

This symbolic mathematics system enables users to solve polynomial multiplications, symbolic differentiations and integrations, simplification of trigonometric expressions, and exact solutions of nonlinear equations. The muMATH-79 programs run on 8080, 8085, and Z80 systems using TRSDOS, standard CP/M, or upward compatible operating systems such as Cromemco CDOS, or IMSAI IMDOS. The program is useful for engineers and scientists in checking or deriving lengthy analytical data. It is also useful for artificial intelligence applications as well as for students and teachers in math education. The price for the package is $190. For more information, contact The Soft Warehouse, POB 11174, Honolulu HI 96828.

Circle 471 on inquiry card.

214 February 1980 © BYTE Publications Inc

Single Board Computer Supports Pascal

DOSC Inc, 500 Fifth Ave, New York NY 10033, has announced its TCB-85 single board microcomputer capable of supporting CP/M and Pascal. The 64 K board is compatible with Intel's Multibus and features a dual-density floppy disk controller that supports up to tour disk drives or two double-sided disks, video display controller with up to 80 characters by 25 lines, RS-232 serial input/output (I/O) port, parallel printer interface, scanned keyboard interface, vectored interrupts, and three timers.

The price is $1500 per unit.

Circle 472 on inquiry card.

Versatile Business Manager System

This system includes a Versatile 4 Dual Drive computer, a Texas Instruments 810 RO Tractor Feed Printer, application software for business, and a movable table. The business software includes a General Ledger, Accounts Payable and Receivable, Inventory, Personnel/Payroll, and Labor Job Cost Analysis. The system is priced at under S8500 and is available from CDS Inc, Building 3, Drummond Plaza, Newark DE 19711.

Circle 473 on inquiry card.

Compucolor II System

Compucolor Corp, POB 569, Norcross GA 30071, has developed three models of the Compucolor II. Model 3 has 8 K bytes of programmable memory, the Model 4 has 16 K bytes, and the Model 5 provides 32 K bytes of memory. The Compucolor II uses an 8080A microprocessor and includes 16 K bytes of read-only memory. One RS-232C serial port is provided for a printer or modem. The Compucolor II features a keyboard that is separate

SYSTEMS

Hewlett-Packard Introduces Personal Computer for Professionals

The HP-85 is a complete computer system designed for use in business and industry by engineers, scientists, accountants, and investment analysts. It can also be used in the home by hobbyists and as an instructional computer in secondary schools, colleges, and universities.

The system features a video display, thermal printer, tape cartridge, and graphics capability in a package the size of a typewriter. It is equipped with four input/output (I/O) ports to allow the user to expand the system to include plotters, printers, disk drives, and other peripherals that are already on the market.

The HP-85 comes with 16 K bytes of programmable memory and can be expanded to 32 K by plugging an optional memory module into one of the ports on the back of the machine. The graphics display is useful to engineers for plotting functions and for test analysis, and to business persons to plot statistics. The display on the screen can be easily printed out on the built-in printer.

The system has a 5-inch, highresolution, black and white video display with 16 lines of display and 32 characters per line. The thermal printer, which operates in both alphanumeric

and graphics modes, prints two 32-character lines per second. The HP-85 tape drive uses HP Data Cartridges, which have a capacity of 200 K bytes, and feature a tape directory that enables the system to automatically find exact tape locations of recorded programs and data.

The HP-85 measures 41 by 46 by 15 cm (16 by 18 by 6 inches), and weighs 9.06 kg (under 20 pounds). It comes with a user's manual and a standard application software package that contains 15 programs. The price of the HP-85 is $3250. For more information, contact Inquiries Manager, HewlettPackard Co, 1507 Page Mill Rd, Palo Alto CA 94304.

Circle 474 on inquiry card.

8086 and 8088-Based Microcomputers

Microbyte, 2499 Cerritos Ave, Signal Hill CA 90806, has introduced two 16-bit 8086 and 8088 microprocessorbased computers with real-time clock, priority vectored interrupts, four port serial input and output (I/O) board that supports four terminals, 32 K bytes of programmable memory, dual-density floppy disk controller that supports up to four drives with direct memory ad

dress (DMA) data transfer, video display and keyboard, 19-slot backplane, and an interrupt switch-on from console to allow re-boot of the system without register destruction. The systems use Microbyte DOS86 batch operating system software and also feature 4 K bytes of programmable memory on-board, 24 operand addressing modes, three programmable timers, and more. The approximate prices for the 8086 and 8088 are $4000 and $3900, respectively.

Circle 475 on inquiry card.

from the processor and video display unit. The video terminal has erase-line and erase-page commands; two character sizes; fifteen plot modes; local, full, and half duplex modes; full cursor control; and other functions. The system uses Disk BASIC 8001 with an interpreter in read-only memory. Twenty-nine statement types, three command types, nineteen mathematical functions, and nine string functions are included.

One 5-inch floppy disk is built into

the main unit. The capacity for each side of a 5-inch disk is 51.2 K bytes.

The video display features eight colors with 32 lines and 64 characters per line. The usable screen area is 23 cm (9 inches) wide by 17 cm (6.75 inches) high. Compucolor has developed software for the system including games, small business applications, home finance, and other programs. The prices for the three models are $1495, $1695, and $1995.

Circle 476 on inquiry card.

February 1980 '- BYTE Publications Inc 215

PUBLICATIONS

Short Form Catalog of Modems and Accessories

This six-page catalog contains RacalVadic's 1200 bits per second (bps) fullduplex acoustic coupler; the "50" series of direct connect modems; and the VA3467 triple modem which emulates a Racal-Vadic VA3400 series modem, a Bell 212A, or a Bell 103. Other products include Bell-compatible 300 bps, 1200 bps half-duplex, and 2400 bps modems; CCITT compatible modems; automatic dialers; and a Multiline Automatic Calling System, which can handle up to 60 modems for each dialing port. For further information, contact Racal-Vadic, 222 Caspian Dr, Sunnyvale CA 94086. Circle 477 on inquiry card.

Introduction to VLSI Systems

Introduction to VLSI Systems, by Carver Mead and Lynn Conway, deals with the theory and practice of designing, fabrication, and implementing of silicon chips, and it provides detailed coverage of the underlying physics to complete very large-scale integration (VLSI) digital computer systems. Introduction to VLSI Systems is suitable as a textbook and reference book for graduate and undergraduate courses.

The book is available from AddisonWesley Publishing Co, Reading MA 01867, for $25.95.

Circle 478 on inquiry card.

Sharp APL Reference

Manual

This text is complete with illustrations and examples, and it discusses the features of Sharp APL in terms understandable by beginners and professional programmers alike. Some of the topics reviewed are syntax of APL, event trapping, primitive functions and operations, structure of data, shared variables, report formatting, batch APL, and line editing in Sharp APL. The manual is available for $18 from 1 P Sharp Associates Ltd, 145 King St W, Toronto, Ontario M5H 1J8, CANADA. Circle 479 on inquiry card.

Communication Fiberoptics Short Form Catalog

Valtec Corp's catalog, which includes their optical fibers and cables, fiberoptic modems and interfaces, and baseband video links, covers every application from computer terminal connections to long-haul telephone and CATV flunking.

To obtain a copy of the catalog, write Valtec Corp, Communication Fiberoptics, 99 Hartwell St, West Boylston MA 01583.

Circle 480 on inquiry card.

1979 Mapping Collection from Harvard Library of Computer Graphics

This six volume collection has been structured to give an organization every kind of information it may need about computer mapping. The collection features works on management's use of maps; natural resource and environmental applications; urban, regional, and

state applications; computer mapping in education; mapping software and cartographic data bases; thematic map design; and sections on cadastral systems and use of satellite derived data. The cost is $45 for the first volume, and $30 for each additional selection. The complete six volume set is $150. Contact the Laboratory for Computer Graphics, Harvard University, 48 Quincy St, Cambridge MA 02138.

Circle 481 on inquiry card.

Publication for the Ohio Scientific Challenger IP

Getting Started With Your Challenger IP introduces the fundamentals of C1P BASIC and explains its characteristics, limitations, and useful features. This document discusses calculator and program mode, input and output, data representation, and program storage on cassette. It also describes ClP control and logic, including testing and branching, subroutine use, and logical operations. This beginner's workbook contains exercises and sample programs. It is available from dealers or by writing to TIS, POB 921, Los Alamos NM 87544. The price is $5.95 plus $1 for postage and handling.

Circle 482 on inquiry card.

Microprocessor User's Guide

The Microprocessor User's Guide contains articles written by engineers for other engineers and corporate managers with a production-oriented, problem solving approach in mind. The 78-page booklet focuses on designing with microprocessors; engineering design approach to microprocessors; microprocessor architecture; analysis of 6800, 8080/8085 and Z80 architectures; and analysis of single-chip microprocessors. Pro-Log's STD BUS, a bus structure for 8-bit microprocessors, is examined in detail.

The guide is available at no charge from Pro-Log Corp, 2411 Garden Rd, Monterey CA 93940.

Circle 483 on inquiry card.

Using a Programmable Calculator Instead of a Central Computer

Providing techniques for using calculators in the HP-67/97 or TI-59 families, the Handbook oj Electronic Design and Analysis Procedures Using Programmable Calculators offers programs and programming techniques for solving problems in network analysis, active and passive filter design, high frequency amplifier design, and engineering mathematics. Documentation including flowcharts, algorithms, sample problems, tips, and references clarify many aspects of problem solution. The book is available for $26.50, from Van Nostrand Reinhold Electrical/Computer Science and Engineering Series, 135 W 50th St, New York NY 10020.

Circle 484 on inquiry card.

216 February 1980 © BYTE Publications Inc

GPIB Controller Implements IEEE 488 Bus and RS-232 Standard

The Model 609 GPIB Controller can be used in place of programmable calculators, microcomputers, or as intelligence for a data collector logger system. Programs in BASIC enter in 4 K bytes of programmable memory, then are transferred to an internal programmable read-only memory (PROM). This eliminates the tape loading routines and insures that, when the controller is turned on, the program is present and ready. The Model 609 has control

features such as serial or parallel poll and reception of binary-coded decimal (BCD) or ASCII messages, the ability to be transparent in a large system, and a front panel pass/fail test system. The front panel contains all connectors and controls and has been designed to eliminate inadvertent false operation. The unit costs $1395. For more information, contact Physical Data Inc, Dept 37, 8220 SW Nimbus Ave, Beaverton OR 97005. Circle 485 on inquiry card.

National Introduces New Addition to One Chip Data Acquisition System Family

Available in two versions, the ADC0808 and ADC0809 complementary MOS (CMOS) integrated circuits incorporate the essential elements of a microprocessor-compatible dataacquisition system onto a single chip, including an 8-bit analog-to-digital (A/D) converter, an 8-channel multiplexer and microprocessorcompatible control logic. The ADC0808/09 uses a successive approximation conversion technique with a high-impedance chopper stabilized comparator which makes the device virtually immune to temperature, long term drift, and input offset errors, and it provides effective and accurate conversion while running on only 15 milliwatts. A 256R voltage ladder network approach was chosen to guarantee against missing codes. Resolution is 8 bits, and the ADC080809 can perform a conversion in 100 microseconds. Latched and decoded address inputs and outputs make possible interfacing to the 8080, 8085, Z80, 6800, and National's 8060 SC/MP microprocessor, among others.

For more intormation on prices and availability, contact Keith Mueller, National Semiconductor, 2900 Semiconductor Dr, Santa Clara CA 95051. Circle 486 on inquiry card.

Magnetic Bubble Mass Storage for DEC Microcomputers

This new LSI-11-compatible bubble memory system is comprised of a dual height controller module (designated Bubbl-Board MBC-11) and one or more dual height bubble memory modules (designated Bubbl-Pac MBB-11). The MBC-11 controller contains its own 8-bit

microprocessor and is capable of controlling up to 16 MBB-11 bubble memory modules. The microprocessor handles bubble device formatting and control, as well as interfacing the bubble memory system to the LSI-11 bus structure. The controller maps standard floppy disk track and sector addresses into bubble device page addresses, so that the bubble memory is fully compatible with all DEC software for the LSI-11, including the mass storage operating systems such as RT-11. The bubble memory system appears just like a floppy disk to the processor, though with much faster access time. Data storage is absolutely nonvolatile. Each MBB-U bubble memory module uses one LSI-11 chassis slot and contains 46 K bytes of storage. Access time to the first data byte averages less than 7 ms.

The MBC-11 is priced at $650 and the MBB-11 at $950. Contact Bubbl-Tec, 3120 Crow Canyon Rd, San Ramon CA 94583. Circle 487 on inquiry card.

The Ruler That Thinks

The Panasonic Electronic Ruler Computer uses a small displacement measuring wheel to directly measure lengths, distances, areas, and volumes, in linear, square, or cubic units, in any scale, from any document. A multifunction calculator is integrated in the ruler permitting measured data to be used automatically in computations. Intermediate measurements can be stored in the calculator's memory to yield a total quantity. The computer displays values directly in millimeters, centimeters or meters, and converts to either inches or feet simply by pressing a function key. The Electronic Ruler-Computer can measure any regular or irregular surface, such as curved walls, floors, containers, etc. Documents to be measured need not be in original scale; variations caused by reduction or enlargement can be programmed into the computer with results automatically displayed in the original scale.

Additional features include addressable memory; metric and area con

version; percent, add-on, and discount computations; automatic square rool and 7r; floating decimal point system; mixed calculations, and more.

The Electronic Ruler/Computer is priced at $99.95. For further information, contact the distributors, Chafitz Inc. 1055 First St, Rockville MD 20850. Circle 488 on inquiry card.

February 1980 © BYTE Publications Inc 217

Whsl'sPJew?

MISCELLANEOUS

S-100 Communications Board

Designed specifically for S-100 applications, Inco's six port EIA/RS-232 board, based on the Zilog Z80A, features synchronous and asynchronous communications at a wide range of data rates. The board also contains two realtime clocks programmable in several modes, and meets the proposed IEEE S-100 standards. It performs hardware cyclic redundancy check (CRC) generation and checking, and provides standard protocol support. The board, documentation and a software guide are available for $895 from Inco Inc, 7916 Westpark Dr, McLean VA 22102. Circle 489 on inquiry card.

Floppy Disk Controller Board for the TM990

A floppy disk controller compatible with the TM990 series of microcomputer board products has been announced by

Texas Instruments Inc, FOB 1433, MS 6404, Houston TX 77001. The TM990/303 board supports up to four double-sided drives. The board is programmable for data encoding formats and number and types of disk drives. The TM990/303 has the ability to interface to single- and dual-density drives. The controller is compatible with IBM 3740 and TI disk formats. Data transfer format and steppermotor rates are both programmable. In addition, the controller also features write precompensation, soft-sector compatibility, internal phase acquisition, and address mark detection. The board is priced at $845. Circle 490 on inquiry card.

MC6809 Microprocessor Development Systems

«\.

Motorola has announced six update packages to adapt a user's previous EXORciser I, IA, or II systems to MC6809 system design. These products enable designers to develop and debug any system centered around this power

ful eight-bit microprocessor. The new EXORciser II and EXORterm 220 differ from the MC6800 units in current production in that they contain a microprocessing module with a M6809 component complement, as well as extending the capabilities of other internal modules to MC6809 specifications. EXORciser and EXORterm systems can be upgraded to permit M6809 designs by adding an MC6809 microprocessing module, a DEbug module, a floppy-disk controller, programmable read-only memory (PROM) firmware, and an MC6809 MDOS floppy disk, containing a macroassembler and video editor. By updating these units for operation with the MC6809 modules, the features of EXORciser II, such as dynamic systems bus, dual memory map, memory parity, second-level interrupt vectors, and more, are achievable.

The prices for the updating systems are $3200. The prices for the complete MC6809-based EXORciser and EXORterm development systems range from $7900 to $9365. For additional information, contact Motorola Inc, POB 20912, Phoenix AR 85036. Circle 491 on inquiry card.

Power Saver from Power Dynamics

Power Dynamics has developed a single output open frame switcher. The unit measures 7 by 10 by 23 cm (2.75 by 4 by 9 inches). It is available in all the standard output voltages from 5 to 48 volts. The price is $175. For more information, contact Power Dynamics Corp, 9421 Telfair Ave, Sun Valley CA 91352. Circle 492 on inquiry card.

Device for Remote Control of Electrical Devices

Introl/X-10 allows Apple users to remotely control 110 V AC devices by commands sent through a BSR/System X-10 Command Console over existing building wiring. The unit comes with software to control devices on predetermined schedules. It provides for selection of daily or weekly schedules, specification of the exact date for a particular event, specification of intervals of time for an event, and, for energy management, device wattage ratings for power consumption accounting. The system consists of the Introl Controller board with timer and ultrasonic transducer, the BSR/X-10 Command Console, and three Remote Modules for $279. The Introl/X-10 Controller Card costs $189 and additional remote modules are available for $15. For more information, contact Mountain Hardware Inc, 300 Harvey West Blvd, Santa Cruz CA 95060.

Circle 493 on inquiry card.

218 February 1980 '- BYTE Publications Inc

32 K Byte Static Memory Boards for 6800/6809

Gimix, 1337 W 37th PI, Chicago IL 60609, is delivering a fully static 32 K byte programmable memory board for use with the SS-50 (6800) and SS-50C (6809) bus. The board features four independently dip-switch addressable 8 K byte blocks. Each block can be addressed to any 8 K boundary or disabled. The board is capable of decoding the tour additional address lines of the SS-50C bus to allow memory decoding up to 1 M bytes. The switches enable or

disable the extended addressing and set it to one of sixteen possible banks. The board is designed for high noise immunity. The price of the full 32 K board is $548.15. The 16 K version costs $328.12 and 24 K version costs $438.14. Both can be expanded to contain up to 32 K bytes of memory.

Circle 510 on inquiry card.

Lowercase and Keyboard Modification Kit for TRS-80

This kit includes wire, solder, control key, 2102 memory device, slide switch, mounting hardware, and documentation. The low power 2102 memory part is connected to a slide switch that allows the TRS-80 to be used with or without lowercase letters. To minimize the chance of damage to the 2102, its connecting wires have been pre-assembled. The control key has gold-plated contacts for long life and can be easily mounted on the keyboard. The kil is priced at

Low Power, 32 K Programmable Memory for Heath H8 Computers

A board with 32 K bytes of programmable memory, using less than 6 W of power and compatible with current Heath peripherals, is available from D-G Electronic Developments Co, 3223 Forest Ln, Garland TX 75042. Other features include circuit protection to prevent damage to memory output buffers if two blocks are assigned to the same address space, memory addressing controlled by a dual in-line (DIP) switch, and it is arranged as four independently addressable 8 K byte blocks with transparent refresh. The price for the board is $479, and it comes fully assembled and tested.

Circle 511 on inquiry card.

$19.95, and is available from Emmanuel B Garcia Jr and Associates, 3950 N Lake Shore Dr, Rm 2310, Chicago IL 60613. Circle 512 on inquiry card.

FREE!

Axiom EX-801 PETPrinter(withgraphics)$ 475.00

Axiom EX-820 PET Plotter $ 749.00

Anderson Jacobson 841 Selectric ... $1015.00

Leedex Video 100 12" Monitor $ 119.00

HeathWH19Terminal(factoryasm.) ...$ 770.00

Heath WH14 Printer (factory asm.) ... $ 735.00

IEEE-RS232PrinterAdaptorforPET... $ 88.00

Up to $170 in merchandise with purchase of one of following PET-CBM items! ! !

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 $ 9.45

Programming the 6502 (Zaks) $ 9.45

6502 Applications Book (Zaks) $ 10.45

6500 Manuals (MOS Technology) .... $ 6.50

Programming a Microcomputer: 6502 . $ 8.45 6502 Assembly Language

(Osborne) NEW! $ 8.10

All Books and Software 15% Off

CBM Word Processor for PET-Machine Language Auto Scroll, insert, delete, form letter append, etc. 8K Version $24.00 16Kor32K with disk $89.00

Cassettes {all tapes guaranteed) AGFA PE611 Premium quality, high out put lownoise in 5 screw housing with labels: C-10 10/5.65 50/25.00 100/48.00 C-30 10/6.90 50/30.00 100/57.00

PET SPECIALS *FREE

PET 16N 16K full size graphics keyboard $995 $130

PET 16B 16K full size business keyboard $ 995 $130

PET 32N 32K full size graphics keyboard $1295 $170

PET 32B 32K full size business keyboard $1295 $170

PET 8N 8K full size graphics keyboard $ 795 $100

PET 2040 DUAL DISK DRIVE-343,000 bytes $1295 $170

PET 2022 Tractor Feed Printer $ 995 $130

PET 2023 Pressure Feed Printer $849 $110

PET C2N External Cassette Deck $ 95 $ 12

Used 8K PETs (limited quantities) $ 495

*Amount of Free Merchandise with Purchase of PET-CBM Item.

K1M-1 $159 (add $30 for power supply) SYM-1 $209

BAS-1 Microsoft ROM Basic for SYM $ 85

Memory Plus (KIM, SYM, AIM) $195

SYM Assembler in ROM $ 85

SEA-16 New 16K Static RAM $325

Seawell Motherboard - 4K RAM Space ... $139

KTM-2/80 Synertek Video Board $349

S-100 16K Static RAM Kit SALE $219

TIS PET Workbooks - set of 6 $ 21.50

Dust Cover for PET $ 8.90

ATARI-INTRODUCTORY SPECIAL

ATARI 400. Alan 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

PET 4 Voice Music System $ 29.90

4 Voice Music Monitor for PET $ 15.90

CmCWordProcessorprogramforPET... $ 25.00

Adventures by Scott Adams 15% Off

SALE

3M "Scotch" 8" Disks 10/$31.00

3M "Scotch" 5" diskettes ... 10/$31.50

Verbatim 5" diskettes 10/$26.50

Diskette Storage Pages 10/$ 3.95

Disk Storage Boxes 8" $2.85 514" $1.95 (Write for quantity prices)

2716 EPROM (5 volt) $ 39

6550 RAM (for 8K PET) $ 1 2.70

6502 $9.75 6522 $9.00 6520 $5.50

2114L450ns$5.35 24® $4.95 100 @ $4.45

115 E. Stump Road Montgomeryville, PA 18936

(215)699-8386 699-5826

A B Computers

MINIMAX

by COMPU/THINK

MINIMAX I (.8 Megabyte Disks] $4495 MINIMAX II (2.4 Megabyte Disks) $5995

SPECIAL—MINIMAX prices include Compu/ Think PAG EMATE Database and Report Writer at no charge.

The most advanced complete microcomputer system available.

Includes CPU, 12" CRT, Full Keyboard, 2 Quad-Density Disk Drives, 2 Megahertz 6502 Hybrid Processor {double speed), 108 K System Memory, High Resolution (512 x 240) Graphics, Programmable Character Fonts, Microsoft Extended BASIC, DOS with Random Access I/O, Full Complement of I/O Ports, Monitor with Debug, Trace, and Tiny Assembler, Fifth (PL/M and Forth combination) Interpreter, Complete editing and entry with split screen capability, 64 Microprogrammable Opcodes, Business software (with Database) available.

WRITE FOR COMPLETE CATALOG

Add $1.00 per order for shipping.

We pay balance of UPS surface charges on all prepaid orders.

Circle 237 on inquiry card.

February 1980 © BYTE Publications Inc 219

What's New?

MISCELLANEOUS

tiny FORTH 2.1 for TRS-80

The Software Farm, FOB 2304, Reston VA 22090 has developed the tinyFORTH 2.1 system for TRS-80 systems. Programs written in tinyFORTH can run faster and use less memory than similar programs in BASIC because tinyFORTH includes a

compiler in addition to an interpreter. This system includes a powerful text editor, a Z80 assembler, and a graphics package. The tinyFORTH system occupies 8 K bytes of memory and comes with cassette tape and documentation for 16 K Level II TRS-80s. The system costs S29.95.

Circle 500 on inquiry card.

32 K Structured BASIC

Cromemco 32 K Structured BASIC, which runs in 64 K Cromemco Systems, assists a programmer in building a program from logical blocks of code. This facilitates program development and reduces debugging and maintenance of programs. It contains all features of 16 K BASIC plus long variable names of up to 31 characters, statement labels that replace statement numbers to reference lines in a BASIC program, an

in-line BASIC editor, a keyed sequential access method (KSAM), procedures, and control structures including if . . . then . . . else.while . . . endwhile, and repeat . . , until.

Cromemco 32 K Structured BASIC is available for use on Cromemco systems on 8-inch or 5-inch floppy disks for $295. For additional information, contact Cromemco Inc, 280 Bernardo Ave, Mountain View CA 94043.

Circle 501 on inquiry card.

Motorola Introduces MC68000 Design Module

Motorola has introduced the MEX68KDM, an MC68000 design module. The MEX68KDM permits easy chip evaluation, using either an EXORciser development system or an IBM370 or PDPII, in conjunction with crosscomputer software. For system emulation, the module includes 32 K bytes of programmable memory, two 16-bit parallel input/output (I/O) ports, three 16-bit programmable timers and two serial RS-232 ports.

MEX68KDM includes MACSbug, a powerful 16-bit microprocessor debugging tool. Once a memory file is resident in programmable memory, a user may

begin his program debugging. The memory map for the MEX68KDM allows for the use of any of the on-card I/O and additional external memory or I/O. A 6800 bus interface card is provided to allow the MEX68KDM to read or write data to an external memory or I/O card. The design module may be used in a stand-alone mode, in an EXORciser development system in the nonexpanded bus mode, or in a card cage with standard 6800 memory.

The design module with two RS-232 cables is priced at $1795. Contact Motorola Semiconductor Inc, POB 20912, Phoenix AZ 85036, for more information.

Circle 502 on inquiry card.

PROSYS I System

Aimed primarily at the process control and industrial/measurement markets, the system allows a process control engineer or technician to communicate with a digital computercontrolled process system. PROSYS I includes the ADAC System 1000 enclosure with the 64 K byte version of the Digital Equipment Corp LSI-11/2 microcomputer, dual-port serial interface, single drive, double-density floppy disk and video terminal. The software resides in less than 32 K bytes of memory. The software includes an operating system. The system can accomodate up to eighteen PROSYS I optional modules. The price lor the system is $14,000, and it is available from ADAC Corp, 70 Tower Office Park, Woburn MA 01801.

Circle 503 on inquiry card.

Multiuser Operating System for Micropolis Microdisk

Micropolis Corp, 7959 Deering Ave, Canoga Park CA 91304, is marketing their fully integrated rigid disk subsystem which includes their 8-inch rigid disk drive with up to 31.2 M bytes ol formatted data storage capacity, an intelligent disk adapter-interface card, and a software package for microcomputer systems that use the S-100 bus. The Microdisk subsystems are available in capacities of 6.2, 18.7 and 31.2 M bytes and are expandable by daisy chaining. Up to three add-on modules may be connected to a master unit. Prices for the Microdisk system begin at under $5000.

Circle 504 on inquiry card.

S-100 16-Channel 12-Bit Analog to Digital Converter Board

The Tecmar S-100 Analog to Digital (A/D) board interfaces the Analogic MP 6812 Complete Data Acquisition System to the S-100 bus. The board accepts sixteen single ended inputs and has data rates up to 30 kHz with twelve bit accuracy. The total of multiplex settling time and sample-hold acquisition time is about 7 microseconds. The board provides two's complement right-justified outputs and variable voltage ranges. The board may be configured to act as an input/output (I/O) device or to act as a memory mapped device. The board requires little software. The price is $495, and it is available from Tecmar Inc, 23414 Greenlawn Ave, Cleveland OH 44122.

Circle 505 on inquiry card.

220 February 1980 © BYTE Publications Inc

af8 New?

MISCELLANEOUS

Network Information Resource

The SOURCE is a computer-based electronic message and information system. It allows users to send messages over computer terminals via a nationwide switching network. The SOURCE provides advanced electronic mail features such as text editing, scanning, delayed delivery, interactive conversation, and bulletin boards. It also acts as an information supermarket offering news, educational programs, travel and shopping services, and much more. To use the SOURCE, subscribers need only a microcomputer or terminal. The cost of the service is $100 initial registration fee plus $2.75 an hour. The service is $15 an hour between 7 AM and 6 PM, Monday thru Friday. For information, contact Telecomputing Corp of America, 1616 Anderson Rd, McLean VA 22102.

Circle 506 on inquiry card.

S-100 Card Adds Sound

Two General Instrument AY-3-8910 programmable sound generators are interfaced to the S-100 bus on the Noisemaker to create sounds and noises. The board provides six tone generators, two noise sources, two envelope generators and four 8-bit input/output ports. Sound effects and noises may be created and added to graphics and computer games. An on-board audio amplifier and breadboard area allows inclusion of the board into any system. The Noisemaker is available now as an unpopulated, solder masked and screened, printed circuit board for $34.95. Contact Ackerman Digital Systems, Suite 208, 110 York Rd, Elmhurst IL 60126.

Circle 507 on inquiry card.

Double-Density Floppy Disk Interface

Tarbell Electronics has released its new interface board, which is supplied with the BASIC INPUT/OUTPUT SYSTEM software for CP/M on singledensity floppy disk, permitting users to mix single- and double-density disks. As

many as four drives can be selected, using either single- or double-density. The 8-inch, Shugart-compatible disk interface contains phase-lock-loop and write precompensation, and the bootstrap programmable read-onlymemory (PROM) is disabled on completion of the bootstrap operation, freeing all 64 K bytes of memory for other use. Extended addressing capability provides eight additional address bits as specified by the new IEEE standard, allowing direct transfers to and from any location within a 16 M byte address range. The interface comes with BIOS for CP/M on floppy disk for $425 from Tarbell Electronics, 950 Dovlen PI, Suite B, Carson CA 90746.

Circle 508 on inquiry card.

Package Turns Exidy Sorcerer into Z80 Development System

Available for $99, a software package called the Development Pac can turn an Exidy Sorcerer into a sophisticated, cassette-based, Z80 development system. The package includes four modules: a

designer's debugging tool (DDT), a lineoriented text editor, a relocating assembler, and a linking loader. All can operate with the Sorcerer's dual cassette interface to allow tape-based system development. The system supports global symbols for intermodule communication and allows the user to define the input/output (I/O) devices for source code, object code, and listings. The debugging tool allows the user to display and modify any programmable memory location or any Z80 register. Using the Development Pac, a programmer can design a program that is far larger than the Sorcerer's memory without having to worry about size limits, due to partitioning of memory and two predefined buffers that can be used for program storage. The package is available from Exidy Data Systems, 2599 Garcia Ave, Mountain View CA 94043.

Circle 509 on inquiry card.

8086 Boards

CPU with $650.

Vectored Interrupts PROM-I/O $495.

RAM $395.

8K x 16/16K x 8

ANALOG Boards

A/D 16 Channel, $495. 12 Bit, High Speed

D/A 4 Channel, $395. 12 Bit, High Speed

VIDEO DIGITIZATION

Real Time Video $850. Digitizer and Display Computer Portrait System $4950.

S-100 Boards

Video and/or Analog Data Acquisition Microcomputer Systems

EC RR

SNC.

The High Performance S-100 People

TECMAR, INC.

23414 Greenlawn • Cleveland,OH 44122 (216) 382-7599

February 1980 © BYTE Publications Inc 221

TRS-80ES SERIAL I/O

• Can input into basic

• Can use LLIST and LPRINT to output, or output continuously • RS-232 compatible • Can be used with or without the expansion bus • On board switch selectable baud rates of 110,150,300,600, 1200, 2400, parity or no parity odd or even, 5 to 8 data bits, and 1 or 2 stop bits. D.T.R. line • Requires +5, -12 VDC • Board only $19.95 Part No. 8010, with parts $59.95 Part No. 801OA, assembled $79.95 Part No. 8010 C. No connectors provided, see below.

EIA/HS-232

DB25P $6.00. wich 9'. 8 conductor cable S10.95 Part No. DB25P9

3' nbbon cable with attached connectors to fitTRS80 and our serial boacdS19.95Part No. 3CAB40.

RS-232/ TTL INTERFACE

• Converts TTL to RS232, and converts RS232 to TTL • Two separate circuits • Requires -12 and +12 volts • All connections go to a 10 pin gold plated edge connectorf kit $ 9.95 Part No. 232A 10 Pin edge connector $3.00 Part No. 10P,

**

MODEM

• Type 103 • Full or half duplex • Works up to 300 baud • Originate or Answer • No coils, only low cost components • TTL input and output-serial

• Connect 8 fi speaker and crystal mic. directly to board • Uses XR FSK demodulator • Requires +5 volts • Board only $7.60 Part No. 109, with parts$29.95Part No. 109A

DISKETTES

Verbatim

Box of 10, 5" $29.95, 8" $39.95. Plastic box, holds 10 diskettes, 5" - $4.50, 8"-$6.50.

RS-232/TTY INTERFACE

This board has two active circuits, one converts RS-232 to 20mA, and the other converts 20mA to RS-232. Requires +12 and -12 volts. $9.9 5 Part No. 600A Kit.

S-100 BUS ACTIVE TERMINATOR

Board only $14.95 Part No. 900. with parts $24.95 Part No. 900A

apple ii-::

SERIAL I/O INTERFACE

Baud rate is continuously adjustable from 0 to 30,000 • Plugs into any peripheral connector • Low current drain. RS-232 input and output • On board switch selectable 5 to B data bits, 1 or 2 stop bits, and parity or no parity either odd or even • Jumper selectable address • SOFTWARE • Input and Output routine from monitor or BASIC to teletype or other serial printer • Program for using an Apple II for a video or an intelligent terminal. Also can output in correspondence code to interface with some selectrics. • Also watches DTR • Board only $15.00 Part No. 2, with parts $42.00 Part No. 2A, assembled $62.00 Part No. 2C

8K EPROM piiceon

Saves programs on PROM permanentlytuntil erased via U V light) up to 8K bytes. Programs may be directly run from the program saver such as fixed routines or assemblers. • S100 bus compatible • Room for 8K bytes of EPROM non-volatile memory (2708's). • Onboard PROM programming • Address relocation of each 4K of memory to any 4K boundary within 64K ■ Power on jump and reset jump option for "turnkey" systems and computers without a front panel • Program saver software available • Solder mask both sides • Full silkscreen for easy assembly. Program saver software in 1 2708 EPROM $25. Bare board $35 including custom coil, board with parts but no EPROMS $139, with 4 EPROMS $179, with 8 EPROMS $219.

WAMECO PRODUCTS WITH ELECTRONIC SYSTEMS PARTS FDC-1 FLOPPY CONTROLLER BOARD will drive shugart, pertek, remex 5" & 8" drives up to 8 drives, on board PROM with power boot up, will operate with CPM (not

included). PCBD $42.95

FPB-1 Front Panel. (Finally) IMSAI size hex displays. Byte or instruction single step.

PCBD $42.95

MEM-1A BKxB fully buffered, S-100, uses 2102 type RAMS.

PCBD $24.95, $1 68 Kit

QMB-12 MOTHER BOARD, 13 slot, terminated, 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 independent interrupts. Software programmable. PCBD .........

EPM-1 1702A 4K EPROM

are SE

card PCBD $25.95

$49.95 with parts less EPROMS

EPM-2 2708/2716 16K/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 2114 Board PCBD $25.95, $269.95 Kit

T.V. TYPEWRITER

• Stand alone TVT

• 32 char/line, 16 lines, modifications for 64 char /line included

• Parallel ASCII (TTL) input • Video output

• 1K on board memory

• Output for computer controlled curser • Auto scroll • Nondestructive curser • Curser inputs: up, down, left, right, home, EOL, EOS • Scroll up, down

• Requires +5 volts at 1.5 amps, and -12 volts at 30 mA • All 7400, TTL chips • Char. gen. 2513 • Upper case only • Board only $39.00 Part No. 106, with parts $145.00 Part No. 106A

UART& BAUD RATE GENERATOR

• Converts serial to parallel and parallel to serial • Low cost on board baud rate generator • Baud rates: 110, 150, 300, 600, 1200, and 2400 • Low power drain +5 volts and -12 volts required • TTL compatible • All characters contain a start bit, 5 to B data bits, 1 or 2 stop bits, and either odd or even parity. • All connections go to a 44 pin gold plated edge connector • Board only $12.00 Part No. 101, with parts $35.00 Part No. 101 A, 44 pin edge connector $4.00 Part No. 44P

TAPE INTERFACE

• Play and record Kansas City Standard tapes

• Converts a low cost tape recorder to a digital recorder • Works up to 1200 baud •Digital in and out are TTLserial • Output of board connects to mic. in of recorder • Earphone of recorder connects to input on board

• No coils • Requires +5 volts, low power drain • Board only $7.60 Part No. 111, withparts$29.95Part No. 111A

HEX ENCODED KEYBOARD

E.S. This HEX keyboard has 19 keys, 16 encoded with 3 user definable. The encoded TTL outputs, 8-4-2-1 and STROBE are debounced and available in true and complement form. Four onboard LEDs indicate the HEX code generated for each key depression. The board requires a single +5 volt supply. Board only $15.00 Part No. HEX-3, with parts $49.95 Part No. HEX3A. 44 pin edge connector $4.00 Part No. 44P.

DC POWER SUPPLY

• Board supplies a regulated +5 volts at 3 amps., +1 2, -1 2, and -5 volts at 1 amp. • Power required is 8 volts AC at 3 amps., and 24 volts AC C.T. at 1.5 amps. • Board only $12.50 Part No. 6085, with parts excluding transformers $42.50 Part No. 6085A

Tn QrHpr ■ 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 handling. 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 DeP{- B p- °- Box 21638, SanJose, CAUSA 95151

222 BYTE February 1980

COMPUCRUISE

Put a computer in your car, which gives you the most effective and functional cruise control ever designed, plus complete trip computing, fuel management systems, and a remarkable accurate quartz crystal time system. So simple a child can operate, the new CompuCruise combines latest computer technology with

state-of-the-art reliability in a package which will not likely be available on new cars for years to come • Cruise Control • Time, E.T., Lap Timer, Alarm •Time, Distance, Fuel to Arrival • Time, Distance, Fuel to Empty • Time, Distance and Fuel on Trip • Current or Average MPG, GPH •Fuel Used, Distance since Fillup • Current and Average-Vehicle Speed • Inside, Outside or Coolant Temperature • Battery Voltage • English or Metric Display. £169.95 , without cruise control $129.95.

i: E

FLOPPY DISK STORAGE BINDER

This black vinyl three-ring binder comes with ten transparent plastic sleeves which accommodate either twenty, five-inch or ten, eight-inch floppy disks. The plastic sleeves may be ordered separately and added as needed. A contents file is included with each sleeve for easy identification and organizing. Binder & 10 holders $14.95 Part No. BBDO; Extra holders 95* each. Part No. 800

OPTO-ISOLATED

PARALLEL INPUT

BOARD FOR

APPLE II

There are 8 inputs that can be driven from TTL logic or any 5 volt source.The circuit board can be plugged into any of the 8 sockets of your Apple II. It has a 16 pin socket for standard dip ribbon cable connection.

Board only £15.00. Part No. 120, with parts £69.95. Part No. 120A.

TIDMA

•Tape Interface Direct Memory Access • Record and play programs without bootstrap loader (no prom) has FSK encoder/decoder for direct connections to low cost recorder at 1200 baud rate, and direct connections for inputs and outputs to a digital recorder at any baud rate • S-100 bus compatible • Board only £35.00 Part No. 112, with parts £110 Part No. 112A

SYSTEM MONITOR

8080, 80B5, or Z-BO System monitor for use with the TIDMA board. There is no need for the front panel. Complete with documentation

S12.95.

16KEPROM

Uses 2708 EPROMS, memory speed selection provided, addressable anywhere in 65K of memory, can be shadowed in 4K increments. Board only $24.95 part no. 7902, with parts less EPROMs $49.95 part no. 7902A.

ASCII KEYBOARD

TTL & DTL compatible • Full 67 key array

• Full 128 character ASCII output • Positive logic with outputs resting low • Data Strobe

• Five user-definable spare keys • Standard 22 pin dual card edge connector • Requires +5VDC, 325 mA. Assembled & Tested. Cherry Pro Part No. P70-05AB. £1:19.95.

ASCII KEYBOARD

53 Keys popular ASR-33 format • Rugged G-10 PC. Board • Tri-mode MOS encoding • Two-Key Rollover • MOS/DTL/TTL Compatible • Upper Case lockout • Data and Strobe inversion option • Three User Definable Keys • Low contact bounce • Selectable Parity • Custom Keycaps • George Risk Model 753. Requires +5, -12 volts. £59.95 Kit.

ASCII TO CORRESPONDENCE CODE CONVERTER

This bidirectional board is a direct replacement for the board inside the Trendata 1000 terminal. The on board connector provides RS-232 serial in and out. Sold only as an assembled and tested unit for £229.95. Part No. TA1000C

DISK JACKET"

Made from heavy duty .0095 matte plastic with reinforced

grommets. The minidiskette version holds two 5-1/4 inch diskettes and will fit any standard three ring binder. The pockets to the left of the diskette can be used for listing the contents of the disk. Please order only in multitudes of ten. £9.95/10 Pack.

ATARI 800

Computer with BK £995.00, disk drive £549.00, printer $599.99

VIDEO TERMINAL

16 lines, 64 columns • Upper and lower case

• 5x7 dot matrix • Serial RS-232 in and out with TTL parallel keyboard input • On board baud rate generator 75, 110, 150. 300, 600, & 1200 jumper selectable • Memory 1024 characters (7-21L02)

• Video processor chip SFF96364 by Neculonic • Control characters (CR, LF, -♦, <-, t, i, non destructive cursor, CS, home, CL

• White characters on black background or vice-versa • With the addition of a keyboard, video monitor or TV set with TV interface (part no. 107AJ and power supply this is a complete stand alone terminal • also S-100 compatible • requires + 16, & -16 VDC at 100mA, and BVDCat 1A. Part No. 1000A £199.95 kit.

RS-232/20mA INTERFACE

This board has two passive, opto-isolated circuits. One converts RS-232 to 20mA, the other converts 20mA to RS232. All connections go to a 10 pin edge connector. Requires +12 and -12 volts. Board only $9,95, part no. 7901, with parts $14.95 Part No. 7901A.

COMPUCOLORII

Model 3, 8K $13 95, Model 4, 16K $14 95, Model 5, 32K£16 95. Prices include color monitor, computer, and one disk drive.

n

L

PET COMPUTER

With 16K S. monitor £ 795. Dual Disk Drive- £10 95

^nppfcz

APPLE II PLUS

16K - £975, 32K $1059, 48K - £1123. Disk&cont. £589

CASSETTE TAPE ERASER

REMOVES RECORDINGS IN ONE SECOND! The process eliminates static positive / negative ions and maintains original tone quality with minimal tape hiss • To improve tone quality • To reduce hissing • For quick and easy to erase • No battery or liquid required • Powerful and effective action • Unconditional 2 year guarantee.

ERASER-8 £19.95.

1SK RAMS

For the Apple, TRS-80 or Pet $8 each Part No. 4116/ 2117.

APPLE II HOBBY/

PROTOTYPING

CARD

$14.95 Part No. 7907

T.V. INTERFACE

• Converts video to AM modulated RF, Channels 2 or 3. So powerful almost no tuning is required. On board regulated power supply makes this extremely stable. Rated very highly in Doctor Dobbs' Journal. Recommended by Apple • Power required is 12 volts AC C.T., or +5 volts DC • Board only £7.60 part No. 107, with parts £13.50 Part No. 107A

PARALLEL TRIAC

OUTPUT BOARD

FOR APPLE II

This board has 8 tnacs capable of switching 110 volt 6 amp loads (660 watts per channel) or a total of 5280 watts. Board only £15.00 Part No. 210, with parts £119.95 Part No. 210A.

TA r\rriar • 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 handling. 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

P. 0. Box 21638, San Jose, CA USA 95151

Circle 164 on inquiry card.

BYTE February 1980 223

Circle 165 on inquiry card.

Hie IMBl-TRANS1000

A completely refurbished , ' IBM Selectric Terminal \vitli1™ built-in ASCII Interface.

&&?i

■

Features:

$1495

300 Baud

14.9 characters per second

printout

Reliable heavy duty Selectric

mechanism

RS-232C Interface

Documentation included

GO day warranty -parts and

labor

High quality Selectric printing

Off-line use as typewriter

Optional tractor feed available

15 inch carriage width

SERIAL I/O

Four Serial I/O RS232 ports, S-100 Bus, Software or jumper selectable baud rates (110, 300, BOO, 1200. 2400, 4800, 9600. 19.2K), on board Xtal baud rate generator, Addressing, switch selectable, Parity or no parity (odd or even) switch selectable, 1 or 2 stop bits, 5 to 8 bits/character. Board only $29.95, Part No. 7908. With parts (kit) $199.95, Part No. 7908A.

HOW TO ORDER DATA-TRANS 1000

1. We accept Visa, Master Charge. Make cashiers checks or personal check payable to:

DATA-TRANS

2. All orders are shipped F.O.B. San Jose, CA

3. Deliveries are immediate

For orders and information

DATA-TRANS

2154 OToole St.

UnitE

San Jose, CA 95131

Phone: (408) 263-9246

TTL parallel, TTL serial. RS232C serial. 20 mil loop serial. Quiet, clean — no ribbons or ink; 24 characters/second; Upper/lower case 96 ASCII characters; Signalling rates: Serial Mode — 110 or 300 Baud; Parallel mode — up to 960 characters/second; For applications over 48 columns, automatically prints on next line; Prints 1 character at a time — ideal for interactive applications; Local line feed for advancing paper; Parity check (odd, even or none); ASCII control codes: back space, carriage return, line feed (implemented as a new line), vertical tab (1 line), negative vertical tab (on receipt of ESC, VT), Bell (9 microsecond pulse on receipt of BEL) PS-4BC Printer $699, with Keyboard, $895. Paper roll 5Vs"x164'$3.00

44 BUS MOTHER BOARD

Has provisions for ten 44 pin (.156) connectors, spaced 3/4 of an inch apart. Pin 20 is connected to X, and 22 is connected to Z for power and ground. All the other pins are connected in parallel. This board also has provisions for bypass capacitors. Board cost $15.00 Part No. 102. Connectors

$3.00 each Part No. 44WP.

GAME PADDLES

& SOUND For Your TRS 80 (Level II or Disk)

Includes: 2 game paddles, interface, software, speaker, power supply, full documentation including: schematics, theory of operation, and user guide; plus 2 games on cassette (Pong and Starship War). $79.95 Complete Part No. 7922C

LEEDEX MONITOR

CI

12" Black and White* 12 MHz Bandwidth • Handsome Plastic Case«$139.00

DIGITAL CASSETTE

5 min. each side. Box of 10 $9.95.

Tq Qrfjpr ■ 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 handling. 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 P0- Box 21638, San Jose, CAUSA 95151

224 BYTE February 1980

Circle 164 on inquiry card.

i

Dial: 402-987

ill/Ill/Ill7i

LINE

i

YOU NEED CRISP, HIGH CONTRAST BUCK-WHITE and VIVID COLOR ALPHA-NUMERICS/GRAPHICS 'capabilities FROM YOUR VIDEO MONITOR IF YOU WANT REALLY SUPER-LOOKING IMAGES FROM YOUR COMPUTER

AS SPECIALISTS IN VIDEO IMAGING ...we Think we have the right monitor or modulator tor your system. Our product line Includes the popular "Micro-Verter" (OSI and Apple Inc. approved UHF color modulator), a variety of color and B-W monitors, color cameras, B-W cameras, Audio subcarrier kits and parts. FREE CATALOG UPON REQUEST. Dealers welcomed. Well established program with over 400 dealers,

ATV Research 13-bbroadway Dakota city, ne.bbt3I

SURPLUS ELECTRONICS

ASCII

ASCII

IBMSELECTRIC

BASED I/O TERMINAL

WITH ASCII CONVERSION

INSTALLED $645.00

• Tape Drives • Cable

• Cassette Drives • Wire

• Power Supplies 12V15A, 12V25A, 5V35A Others, • Displays

• Cabinets • XFMRS • Heat Sinks • Printers • Components

Many other items, SEND $ 1.00 FOR CATALOG REFUNDABLE FIRST ORDER WORLDWIDE ELECT, INC. 130 Northeastern Blvd. Nashua, NH 03060

Phone orders accepted using

VISA or MC

Call 603-889-7661

SHORT »50 ft. CASSETTES

At' 1

s #

■■•

50 1

MKJSOBfcTT* tl>

m P.*™ 6«Ba™dsC*

,ws" H

■ '-.'

Qty. Price

1 $1.00

10 $0.75

50 $0.65

Circle 166 on inquiry card.

Circle 167 on inquiry card.

Premium tape and cassettes acclaimed by thousands of repeat order microcomputer users. Price includes labels, cassette box and shipping in U.S.A. VISA and M/C orders accepted. California residents add sales tax. Phone (415) 968-1604.

MICROSETTE CO.

475 Ellis Street Mt. View, CA 94043

Circle 168 on inquiry card.

SATELLITE TRACKING SOFTWARE

SATTRAK INTERNATIONAL

SATELLITE THANKING BASIC anr] FORTRAN A Each puirjiam series jj

1:01: H.M.1E:: PftNGE ■-.

illow you In operjle your v.vr, r.F'ACF CENTRE and The SBfnS SOPHISTICATED ALGORITHMS are in Cold rams use EASY INPUTS lr:r thinner nr educational use -.5 LATITUDE'LOUGSTUDE'ALIirUDE.'AJ'tMUTHiELEVAirr.N PAST/PRESENT or FUILRE. plug ihnso loalures: layl • VISIBLE'ALL PASS opnons

■ lull SELF TESTrr

) run'.' or-uralors manual • Handles all tyuns of ornils

TRAWUPOAT + GRAPHICS lapcclly computer, caSHG-tti! or (lis POSMILOOK,'OBS.'UPDAKs|ii;<;.rycnmpulei,c,]=sollr,oroi!.c)

'JDOC TRAKIPDSIl.LOOK.DICi HI-MAI rii;-;,f.-!ht; (apeci'/ compulcrl

9000 TRAKiPOSrj iQG'.-G'V. -iphatf M'.c [specify compiileD .

BOTFL FORTRAN LISTING POSH-LOOK,DBS + 15 SUEROUTItJES (with ASCII STANDARD CARD FORMAT. 1200 CARDS)

30QHL BASIC LISTING iM..t'0'.jii Bnsir.^cpsify compulerl .

■ i-r(Lt ■■

a us ai

Send cheque/money order to: SAT TRAK International

c/o Computer-land of Colorado Springs

4543 Tempteton Gap Road

Colorado Springs CO USA 80909

Colorado residents add 5% sales tax.

TRS-80 users

Learn FORTH

FORTH is ;i structured high level language thai dramatically cuts program development time. You can expand the FORTH language by defining new operations and data types. FORTH programs arc compiled to reduce memory space and speed execu

tinyFORTII is a complete version of the powerful FORTH language tailored to the TRS-80, The tinyFORTH system includes FORTH, a text editor, an assembler, graphics, and cassette I/O. Learn FORTH on your own computer. 'Hie tinyFORTH user's manual contains hundreds of examples to teach you FORTH in a hands-on style. tinyFORTH lor 16k level II TRS-80:

Cassette and full documentation $29.95

Documentation only S 9.95

All orders are fully guaranteed. And S.I ,50 for postage and handling. Order with check, money order. Visa, or Maslercharee.

Write for a FREE booklet describing FORTH.

The Software Farm

Reston. VA 221)90

Dept. A15

Put

SARGON IP

on Disk

Send a SASE and $5 to:

RCV Consultants, Dept B

9459 Taylorsville Road

Dayton, Ohio 45424

for complete instructions enabling you to copy your Hayden tape to disk. Implementation relocates the tape-loaded machine-language code from low to high memory during DOS operation, and during game-play disables the monitor vectors which would point into SARGON II code, thus avoiding critical memory conflicts.

All you have to do is type in and run a 4-statement BASIC program, and it does everything necessary to make the tape-loaded SARGON II code ready for disk storage, retrieval, and game-play. As a bonus, you get to keep the DOS 2.2 Keyboard debounce feature during SARGON II operation!

Requires a TRS-80-1 Model I Level II 32 K with one disk drive, and a DOS 2.2 diskette.

1 Copyright 1979 By Hayden Book Company 2 Trade Mark of the Tandy Corporation

Circle 170 on inquiry card.

Circle 171 on inquiry card.

THE SWITCH

OPTO ISOLATED 120 VAC SOLID STATE SWITCH

• INPUT 5 VDC 2 MA (TTL) . ISOLATION 1500 VDC

. OUTPUT 6 A 120 VAC 720 W

• SIZE 2x21 CHANNEL

• SIZE 2x84 CHANNEL PRICE KIT TESTED UNIT 1 CH. $9.95 $12.50

4 CH. $34.95 $44.95

ADD 6% SALES TAX IN CALIFORNIA AND $1.00 SHIPPING & HANDLING FOR ORDERS LESS THAN $20. ADD 4% FOR VISA OR M.C.

JOHN J. BELL

P.O. BOX 338

REDWOOD CITY, CA 94064

(415) 367-1137

STATIC RAM CHIPS

CftPTflDV DDIMC From Hie same shipment we use in our rMUIUni rnllYIC professional quality boards.

2114L450ns.$5.90 200 ns. $6.90

4044 450 ns. .$5.90 250 ns. $6.90

Add $5.00 Handling on Orders Under $200.00

32K STATIC RAM BOARD

OR THE SS50 AND SS50C BUS (SWTP ate.)

SS50C Extended Addressing (can be disabled)

• 4 separate 8K blocks. Low power 2114L RAMS (2 AMPS Typical for 32K) Socketed for 32K Write Protect

• Gold Bus Connectors

16K $328.12

24K $438.14

32K $548.15

Phone, write, or see your dealer for details and prices on ou broad range of Boards and Systems for the SS50/SS50C bus including our UNIQUE 80x24 VIDEO BOARD, and our AC Power Control Products for all computers,

Gimix <&

1337 W. 37th Place • Chicago, IL 60609 (312)927-5510 • TWX 910-221-4055

The Company that delivers.

Quality Electronic products since 1975.

GIMIX1' and GHOST- are Registered Trademarks of GIMIX INC

The best choice in mainframes !

• S100 CARD FRAME • AXIAL BLOWER

• 22 MHz 12" CRT MONITOR • ASSEMBLED & TESTED

• 18 AMP POWER SUPPLY • READY FOR YOUR CARDS

• UPPER & LOWER CASE • S89-5.00 OEM QUANT. ONE ASCII KEY BOARDS

,D

OOU I IM F I IM I T

- (305) 724-1588

Circle 172 on inquiry card.

Circle 173 on inquiry card.

Circle 174 on inquiry card.

Circle 175 on inquiry card.

EXCITING MAILORDER DISCOUNTS

NOVATION CAT

ACOUSTIC MODEM

• ANSWER. ORIGINATE

• 300 BAUD

• BELL 103

• LOW PROPILE DESIGN

s179

[00

Japplc II 16k

OR APPLE I PLUS

$975

APPLEII 32KM050 APPLE IU8K>1126

•COLOR •GRAPHICS •SOUND •APPLE II ACCESSORIES*

APPLE SOFT BASIC CARD M 55

DC HAYES MICROMODEM '335

ALF MUSIC SYNTHISIZER '240

CORVUS 10 MEGABYTE DRIVE '4,650

APPLE DISK II '440

WITH CONTROLLER CARD :'; . . .'495 PASCAL LANGUAGE SYSTEM. .'450 INTEGER BASIC CARD '155

SD EXPANDORAM

•64KS-100 DYNAMIC RAM BOARD •WORKS WITH Z-80. 8080 & 8085 •POWER CONSUMPTION 5 WATTS •BANK SELECT -PHANTOM REFRESH •NO WAIT STATES REQUIRED

WITHOUT MEMORY

16KKIT

32KKII

48K KIT

64K KIT

_$149 00 — 215 00 _269 00 _349 00 _409 00

ADD S50 FOR ASSEMBLED & TESTED

LEEDEX VIDEO 100

12" BLACK & WHITE MONITOR

♦VIDEO BANDWIDTH 1 2 MH^ + 3db •COMPOSITE VIDEO INPUT

$12900

SOROCIQ120

SERIAL RS232C

FULL ASCH II UPPER/LOWER CASE NUMERIC KEYPAD CURSER KEYS SCREEN CONTROLS S7rno0 PROTECTED FIELDS

'750

'ALSO AVAILABLE'

SOROC IQ 140 $1,225.00

•2-80 MICROPROCESSOR •30x64 CHARACTER DISPLAY •S-IOO COMPATIBLE EXPANDABLE •SERIAL AND PARALLEL I 0 •DUAL CASSETTE IO

• 64 USER DEFINABLE CHARACTERS •2-10x5 12 HIGH RESOLUTION GRAPHICS •RESIDENT 4K MONITOR ROM

•FULL SIZE ASCII KEYBOARD

• UPPERLOWER CASE AND NUMERIC KEYPAD

16K S99S 32KS1,145 48K M295

» TO ORDER *

Phono orc!<;r:; invited, using credit cards:.,Or send cashiers chet:k or money order Ihfi! drawi; on a: U;S. bank. Please add 3% (S10 Mtnimum):for handling^ shipping1 (air service) and insurance, or equipment wiii be shipped freight collect, California residents add 6% safes Sax. All equipment i$:'in factory cartons with the manufacturers; warranty. Equipment is subject to price change and availability without notice.

VISA

mmjm.. mrtMm^

.■■■ ' -"•.:. . it- ■ ;

MEMOREX

Floppy Discs

Lowest prices. WE WILL NOT BE UNDERSOLD!! Buy any

quantity 1-1000. Visa Mastercharge accepted. Call free (800)235-4137 for prices and information. All orders sent postage paid.

PACIFIC EXCHANGES

100 Foothill Blvd. San Luis Obispo. CA 93401. (In Cal. call (805)543-1037)

$ MINI FLOPPY AT $ $ STORE DISCOUNT $

SINGLE SIDED-$225.00 DOUBLE SIDED-$345.00

CABINETS-CABLES AND POWER SUPPLIES ARE ALSO AVAILABLE

INTERFACE,INC 20932 CANTARA ST CAN0GA PARK,CA 91304

(213) 341-7914

81999 2399 2765 2799 3215

8000 1149

Save More Than 80%

North Star—Intertube

Thinker Toys—Microtek

The Smartest Computers at the Smartest Price

Quad ft Double Density

List Horizon-1-32K-D Kit Horlzon-2-32K-D Kit

Assembled & Tested Horlzon-2-32K Kit Quad

Assembled 8c Tested Pascal for North Star on Disk Powerful North Star BASIC ZTBI PT 212 Computer 5 mHz Thinker Toys Dlsous/2D A&T Dusous/2 + 2 1.2 Megabytes A&T 1549 Measurement system memory A&T 4mHz 64 K Godbout Memory Call for price

Intertube II Smart Terminal 995 745

Microtek Printer 750 675

Anadex Printer 995 875

Florida Data Printer 600 CPS 4300 Call for price Maryellen Word Processor Your Best Buy 38 Textwriter III

EZ-80 Tutorial Learn Machine Language PDS For North Star Better Than CP/M Compiler for Horizon Secret Superfast Code 10% Off Software Prices With Computers Verbatim the Best Diskettes Box of 10 Which Computers Are Best? Brochure. North Star Documentation Refundable W/HRZ

American Square Gorapntflrs Kivett Dr ' Jamutown NC £7282 (9191-8B3-110S

Only

S1585

1905

2195

2221

2555

49

FREE

6S50

949

1299

640

125 25 99

100

99

FREE 20

Circle 229 on inquiry card.

Circle 230 on inquiry card.

Circle 231 on inquiry card.

226 BYTE February 1980

Super Color S-100 Video Kit $99.95

Expandable to 256 x 192 high resolution color graphics. 6847 with all display modes computer controlled. Memory mapped. 1K RAM expandable 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 8 colors with 6847 chip; 1K RAM at E000. Plugs into Super Elf 44 pin bus. Not expandable to high resolution Graphics.

Elf II Adapter Kit $24.50

Plugs into Elf II providing Super Elf 44 and 50 pin bus plus S-100 bus expansion (With Super Expansion). High and low address displays, state and mode LED's optional $18.00.

1802 16K Dynamic RAM Kit $149.00

1802/S-100 expandable to 32K, Hidden refresh w/clocks up to 4 MHz w/no wait states Addl, 16K RAM $79.00.

Quest Super Basic

Quest, the leader in inexpensive 1802 systems announces another first. Quest is the first company worldwide to ship a full size Basic for 1802 systems. A complete function Super Basic by Ron Cenker including floating point capability with scientific notation (number range ±. 17E3B), 32 bit integer ±2 billion; Multi dim arrays; String arrays: String manipulation; Cassette I/O, Save and load, Basic, Data and machine language programs; and over 75 Statements, Punctions and Operators.

Easily adaptable on most 1802 systems. Requires 12K RAM minimum for Basic and user

programs. Cassette version in stock now. ROM versions coming soon with exchange privilege allowing some credit for cassette version. Super Basic on Cassette S40.00

Tom Pittman's 1802 Tiny Basic Source listing now available. Find out how Tom Pittman wrote Tiny Basic and how to get the most out of it. Never offered before. $19.00

S-100 4-Slot Expansion S 9.95

Super Monitor VI.I Source Listing $15.00 Coming Soon: Assembler. Editor, Disassembler, DA/AD, Super Sound/Music, EPROM programmer.

RCA Cosmac Super Elf Computer $106.95

Compare features before you decide to buy any other computer. There is no other computer on the market today that has all the desirable benefits of the Super Elf for so little money. The Super Elf is a small single board computer that does many big things. It is an excellent computer for training and tor learning programming with its machine language and yet it is easily expanded with additional memory, Full Basic, ASCII Keyboards, video character generation, etc. Before you buy another small computer, see if it includes the following features: ROM monitor; State and Mode displays; Single step: Optional address displays; Power Supply; Audio Amplifier and Speaker; Fully socketed for all IC's; Real cost of in warranty repairs; Full documentation. The Super Elf includes a ROM monitor for program loading, editing and execution with SINGLE STEP for program debugging which is not included in others at the same price. With SINGLE STEP you can see the microprocessor chip operating with the unique Quest address and data bus displays before, during and after executing instructions. Also, CPU mode and instruction cycle are decoded and displayed on 8 LED indicators. An RCA 1861 video graphics chip allows you to connect to your own TV with an inexpensive video modulator to do graphics and games. There is a speaker system included for writing your own music or using many music programs already written. The speaker amplifier may also be used to drive relays for control purposes.

A 24 key HEX keyboard includes 16 HEX keys plus load, reset, run, wait, input, memory protect, monitor select and single step. Large, on board displays provide output and optional high and low address. There is a 44 pin standard connector slot for PC cards and a 50 pin connector slot for the Quest Super Expansion Board. Power supply and sockets for all IC's are included in the price plus a detailed 127 pg. instruction manual which now includes over 40 pgs. of software info, including a series of lessons to help get you started and a music program and graphics target game.

Many schools and universities are using the Super Elf as a course of study. OEM's use it for training and research and development. Remember, other computers only offer Super Elf features at additional cost or not at all. Compare before you buy. Super Elf Kit $106.95, High address option $8.95, Low address option $9.95. Custom Cabinet with drilled and labelled plexiglass front panel $24.95. Expansion Cabinet with room for 4 S-100 boards $41.00. NiCad Battery Memory Saver Kit $6.95. All kits and options also completely assembled and tested. Questdata, a 12 page monthly software publication for 1B02 computer users is available by subscription for $12.00 per year. Tiny Basic Cassette $10.00, on ROM $38.00, original Elf kit board $14.95. 1802 software; Moews Video Graphics $3.50. Games and Music $3.00, Chip 8 Interpreter $5.50.

Super Expansion Board with Cassette Interface $89.95

This is truly an astounding value! This board has been designed to allow you to decide how you want it optioned. The Super Expansion Board comes wilh 4K of low power RAM fully addressable anywhere in 64K with built-in memory protect and a cassette interface. Provisions have been made for all other options on the same board and it fits neatly into the hardwood cabinet alongside the Super Elf. The board includes slots for up to 6K of EPROM (2708, 2758, 2716 or Tl 2716) and is fully socketed. EPROM can be used for the monitor and Tiny Basic or other purposes. A IK Super ROM Monitor $19.95 is available as an on board option in 2708 EPROM which has been preprogrammed with a program loader/ editor and error checking multi file cassette read/write software, (relocatible cassette file) another exclusive from Quest. It includes register save and readout, block move capability and video graphics driver with blinking cursor. Break points can be used with the register save feature to isolate program bugs quickly, then follow with single step. The Super Monitor is written with

subroutines allowing users to take advantage of monitor functions simply by calling them up. Improvements and revisions are easily done with the monitor. If you have the Super Expansion Board and Super Monitor the monitor is up and running at the push of a button. Other on board options include Parallel Input and Output Ports with full handshake. They allow easy connection of an ASCI I keyboard to the input port. HS 232 and 2D ma Current Loop for teletype or other device are on board and if you need more memory there are two S-100 slots for static RAM or video boards. Also a 1K Super Monitor version 2 with video driver for full capability display with Tiny Basic and a video interface board Parallel I/O Ports $9.85, RS 232 $4.50, TTY 20 ma l/F $1.95, S-100 $4.50. A 50 pin connector set with ribbon cable is available at $15.50 for easy connection between the Super Elf and the Super Expansion Board. Power Supply Kit for the complete system (see Multi-volt Power Supply).

TERMS: $5.00 min. order U.S. Funds. Calif residents add 6%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 factory prices.

INTEGRATED CIRCUITS

.66

7400TTL

7400N

74 02^

74 04 "J

7409M

74 ION

74I4N

7420N

7422N

7430N

7442N

7445N

7475N 7-IB5N 7 .ISBN 7490N 7492N 7493N 7495N

741 SON 74151N 7415-1N

74157N 74161N 74162N 741G3N 74174N 74175N 741 SON 741S2N 741S3N 74221N 742S8N 743ESN 743fc"6N 74367N

74LS0O TTL

74LS00N .35

74LS02N .35

74LS04N .35

74LS05N .35

74LS08N 35

74LS1DN 35

74LS13N 55

74LS14N 1 10

74LS20N 35

74LS22N 35

74LS28N 41

74LS30N 35

74LS33N .75

74LS3SN .55

74LS74N 1 25

74LS7SM 1.00

74L390N .05

74LS93N .70

74LS95N 1.10

74LS107N 45

74LS112fJ 45

74LS113N 35

74LS132N 89

74L5136N 45

74LS151N S5

74LS15SN 85

74LS157N .85

74LS162N 1.15

74LS163N 1 15

74LS174N 2 00

74LS190N 1.06

74LS221N 1.95

74LS258N .67

741.S367N 1.35

LINEAR

CA3045 ,90

CA3046 1 10

CA30B1 1.60

CA30B2 1.90

CA3089 2 95 LM301AN'AH 35

LM305H 87

LM307N .35

immn .69

LM309K 150

LM3MH/N .90

LM317T/K 3.75

LM318 1.35

LM320K-5 150

P.O. Box 4430X Santa Clara, CA 95054

fc. For will call only: (40f») 988-164° Ik 2322 Walsh Ave. ^

yc/t_

LM323K-5 5 95 LM32QK-12 1.50 LM32QK-15 150

LM320T-5 1 60 LM320T-8 1 60 LM320T-12 150 LU320T-15 1 60 LM324N 1 15 LM339N 1 55

LM340K-5 1 35 LM340K-8 135 LM340K-12 1 35 LM340K-15 1 35 LM340K-24 1 35 LM340T-5 1 25 LM340T-8 1 25 LM340T-12 1 25 LM34QT-15 1 25 LM340MB 1 25 LM340T-2.1 1 25 LM343H 4.50 LW350 LM370 LM377 LM379 LM380N LM381 LM3B2 I M703H LM709H .M723H/N LM733N

M741CH IM741N

M747H/H . M74BN

Ml 303:'! IM1304 LM1305 LM1307 .M1310 I.MI458 IM1800 LM1812

ELECTRONICS

.15

RESISTORS H wait 5°,

10 per type 03 1000 per lype 012 25 per type 025 350 piece pack 100 per type 015 5 per lype 6.75

ft wall $% per type .05

KEYBOARDS

55 key ASCII keyonarrl kit S67.50

Fully assembled 77.50

53 Hey ASCII keyboard kil 60 00

fully assembled 70.00 Enclosure 14 95

LEDS

Red T018

Green, YdIIow T018

Jumbo Red .20

Green. Orange. Yellow Jumbo 25

Cllpllte LED Mourning Clips ESI 25

(specify reil. amber, green, yellow, clear!

CONTINENTAL SPECIALTIES In stock Complete line of breadboard test equip

MAX-100 B dlgll Freq. Clr. SITE.95

SPECIAL PRODUCTS

MM5B65 Stopwatch Til

PC board

Swllches Mom Pushb'

_3pos

itide

Encoder HD0165-5 3 Digit Universal Counter Board XII

Operates 5-IB Voll DC lo 5

ryp. 125" LED display II Paralronlcs 1G0A Logic Analyzer KM S22.

Model 10 Trigger

Expander Kit S22I

Model 150 Bus

Grabber K.| $36!

Sinclair 3') Oigll

Multimeter SB!

Clock .:. : ■■ Kll S2;

2,5 MM/ Frequency Counter

KM S3

30 MHi Frequency Caualer

12 V

t 300 rr

12.6V CT 600 ma

12V 250 ma wall plug

12V CT 250 ma ajII plug

24V CT 400 ma

10V 1 2 amp wall plug

12V 6 amp

12V 500 ma wall plun

12V 1

ii pi«g

12V 3 amp wall plug DISPLAY LEOS

MAM

MAN3

MAN72/74

DL704

DL7O7/DL707R

DL727'728

DL747/750

DL750

FND3S9

FNO50O/5O7

FHD503/510

FNO80O/8O7

3 digit Bubble

4 digit Bubble DD8 Fiuoresccnl DG10 Fluorescent

5 digit 14 pm display NSNG9 9 rJifjH display 7520 Clairex photocell:; TIL3I1 Hex MAN3640 MAN; i. Hi MAfM6-Ifi

MAN4710

M AN-17.10 MANf'Mu '/ANL710 UArjiiMii MA1002A MA1012A 102P3 Iranslormer

CA .270 2.90

CC .125 39

CA/CA 300 1 00

CC 300 1 25

CA 300 1 00

CAyCC .500 1 90

CA'CC 600 1 95

CC 600 1.95

CC .357 .70

CC.'CA .500 1 35

CC/CA .500 .90

CC/CA .1

.60

CC 56

CA .60 CC 60

ROCKWELL AIM 65 Computer

6502 based single board with full ASCII keyboard and 20 column thermal printer. 20 char, alphanumeric display, ROM monitor, fully expandable. S375.00. 4K version $450.00. 4K Assembler $85.00, 8K Basic Interpreter $100.00.

Special small power supply for AIM 65 assem. in frame $49.00. Complete AIM 65 in thin briefcase with power supply $485.00. Molded plastic enclosure to fit AIM 65 plus power supply $47.50.

AIM 65/KIM/VIM/Super Elf 44 pin expansion board; 3 female and 1 male bus. Board plus 3 connectors $22.95.

AIM 65/KIMA/IM I/O Expansion Kit; 4 parallel and 2 serial ports plus 2 internal timers $39.00. PROM programmer 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 option. =:5v, ±12v are regulated. Kit $29.95. Kit with punched frame $37.45, $4.00 shipping. Woodgrain case $10.00, $1.50 shipping.

PROM Eraser

Will erase 25 PROMs in 15 minutes. Ultraviolet, assembled S37.50

60 Hz Crystal Time Base Kit $4.40

Converts digital clocks from AC line frequency to crystal time base. Outstanding accuracy.

79IC Update Master Manual $35.00

Complete IC data selector, 2500 pg. master reference guide. Over 50,000 cross references. Free update service through 1979. Domestic postage $3.50. No foreign orders.

Not a Cheap Clock Kit $14.95

Includes everything except case. 2-PC boards. 6-.50" LED Displays. 5314 clock chip, transformer, all components and full instructions. Orange displays also avail. Same kit w/,80" displays. Red only. $21.95. Case $11.75

NiCad Battery Fixer/Charger Kit

Opens shorted cells that won't hold a charge and then charges them up, all in one kit w/full parts and instructions. $7.25

S-100 Computer Boards

8K Static RAM Kit S135.00

16K Static RAM Kit 265.00

24K Static 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 Kit 470.00

8K/16KEprom Kit (less PROMS) $89.00

Video Interface Kit $129.00 Motherboard $39. Extender Board $8.99

Video Modulator Kit $8.95

Convert your TV set into a high quality monitor without affecting normal usage. Complete kit with full instructions.

Digital Temp. Meter Kit $34.00

Indoor and outdoor. Switches back and forth. Beautiful. 50" LED readouts. Nothing like it available. Needs no additional parts for complete, full operation. Will measure -100°to + 200°F, tenths of a degree, air or liquid. Beautiful woodgrain case w/bezel $11.75

FREE: Send for your copy of our NEW 1979 QUEST CATALOG. Include 28« stamp.

Circle 177 on inquiry card.

BYTE February 1980 227

Circle 178 on inquiry card.

PRINTED CIRCUIT BOARD

4" x6" DOUBLE SIDED EPOXY

BOARD 1/16" thick

$.60 ea 5/S2.60

EPOXY glass vector hoard

1/16" thick with 1/10" spacing S1.95

VERIPAX PC BOARD $12.95

Oiif new Prototyping board Is a hi density A'/i x 6'/;" single sided 1/16" G-10 board. It will Hold 40, 24, 16 [34 units), 14 * B pin IC's. There are three busses, *5V, ground and a. ' ' if a TO-220 reg

156"

i 22 I

7WATTLD65LASERDIODEIR $a95

TTL REED RELAY - 5PST 5V 20ma S1.00

DAC-08BC - 8 bit DAC - $9.95 8" DISKETTES - HARD SECTOR Si.75, 10/S 16.00

!5 watt Infra Red Pulse I SG 2006 eqjliv, )

.aser Diode <Spec sheet included! $24.35

MINIATURE MULTI-TURN TRIM POTS 100, 2K, 5K, 10K, 20K, IMeg, $.75 each 3/$2.O0

2N 3820 P FET $45

2N 5457 N FET $ 45

2N2646 UJT $ .45

ER 900 TRIGGER DIODES 4 SI 00

?N 6028 PROG UJT S §5

FP 100 PHOTO TRANS S .50

RED, YELLOW, GREEN

LARGE LED's. 2" 6/$1.00

RED/GREEN BIPOLAR LED's.2" . ..95

TIL-118 0PTO-ISOLATOR $.75

MCT-6 OPTO ISOLATOR $ .80

1 WATT ZENERS; 3.3, 4.7, 5.1, 5.6, 9.1, 10, 12, 15, 18, or 22V 6/$ 1.00

Silicon Power Rectifiers

TRANSISTOR SPECIALS

2N6233-NPN SWITCHING POWER . SI.95 MRF-8004 a CB RF Transistor NPN . $ .75

2N3772 NPN Si TO-3 $1.00

2N4908PNP Si TO-3 $1.00

2N5086 PN P Si TO-92 4 $ 1.00

2N3137 NPN Si RF $ .55

2N3919 NPN Si TO-3 RF $1.50

2N1420 NPN Si TO-5 3/$ 1.00

2N3767 NPN Si TO-66 $ .70

2N2222 NPN Si TO-18 5 $1.00

2N3055 NPN Si TO-3 $ .60

2N3904 NPN Si TO-92 6/$ 1.00

2N3906PNP Si TO-92 G/Sl.00

2N5296 NPN Si TO-220 $ .50

2N6109 PNP Si TO-220 $ .55

2N3638PNPSiTO-5 5/S1.00

MPSA 13 NPN Si 4/$ 1.00

TTL IC SERIES

■ZEHHM

1.30

1 90

DIP SOCKETS

^IN .25

SANKEN AUDIO POWER AMPS

Si 1010 G 10 WATTS S 6.75

Si 1020 G 20 WATTS $12.95

Si 1050 G 50 WATTS . . . S25.90

TANTULUM CAPACITORS

CRYSTALS S3.45 oa. 2.000 MHz 6.144 MHi 4.000 MHz 8.000 MHz 3.57 MHz 10.000 MHz 5.000 MHz 20.000 MHz 6.000 MHz

RIBBON CABLE LAT (COLOR CODE M0WIRE

UNIVERSAL 4Kx8 MEMORY BOARD KIT S69.95

322102-1 fully buffered. 16 address linos, or board decoding for any 4 of 64 pages, standaro 44 pin buss, may be used with F-8 & KIM

SILICON SOLAR CELLS I" diameter .4V at 1 AMP $10.00

LED READOUTS

FCS 8024 4 dj C.C. 8" display FND 503 C.C FND 510 C.A. DL 704 .3" C.C.

DL-707C.A. .3"

5.95 DL 747 C.A 6"

85 HP3400 .8" CA

HP3405 .8" CC

10 50 16.50

12.50 20.00

RS232 DB25Pmaie $2.95

CONNECTORS DB 25S femata $3.50

HOODS $1.50

323K - 5V 3A . .$ 5.75 309K ... . .S 1.60

723 S .50

320T

5, 12,or 15 V

REGULATORS

340K - 12, 15

or 24 V. . . .S 1.50 340T - 5, 6,8, 12

15, IBor 24VS 1.30 79MG S1.35

3/Sl.OO

$.40 ea.

MM5387AA . . . CLOCK CHIPS - ■ S5.95

M7001 57.50

MM5311 _S317S_

NO. 30 WIRE WRAP WIRE SINGLE

STRAND 100' $1.40

CO MINIATURE TOGGLE SWITCt MTA 106 SPOT S 1.05

MTA 206 DPDT ... S 1 70

MTA 206 P.DPDT CENTER OFF MSD 206 P-DPDT CENTER OFF LEVER SWITCH. . . . , $ 1.85

.22UF 35V5/S1.00 .47UF 35V5/S1.00 .68UF 35VS/S1.00 1UF 35V 5/S1.00 2.2UF 20V 5/S1.00 3.3UF 20V 4/41.00 4.7UF 15V 5/S1.00

MlS Series

6.8UF 35V 4/51.00

10UF 10V S .25

22UF 25V $ .40

15UF 35V 3/S1.00

30UF 6V 5/S1.00

100UF 15V $ .70

' 160UF 15V $ .35 68 UF 1

74LS03 74LS04 74LS0S 74LS08

74LS28 74LS30 — 74LS32 74LS37— 74LS38 74LS40 74LS42 — 74LSS1 74LS54 74LS73 74L574 — 74LS75 74L576

74L.593 74LS1Q774LS100

74LS114 74LS125 74LS126

74L5: 74 LG 74LS;

74LG221 74LS107 74LB240

5 74LS251—

5 74LS257

5 74LS25B —

05 74LS253 —

>9 74LS265

E 74LS2C6 —

5 74LS279 —

'0 74L5290 —

'0 74LG293

° 74LS29S

74LS36774LS36B74LS273

9 74LS390 — 1.95

LINEAR CIRCUITS

LM201 — .75 LM301/748 - .25 LM307 - .30 LM308 - .75 LM311 — .75 LM318 — 1.20 LM324 — .95 LM339 - 1.10 LM358 - .70 LM370 — 1.15 LM377 — 1.60 LM380 — .95 LM382 - 1.25 LM386 - .80 LM387 — 1.25 LM1800 — 2.20 LM1B0B — 1.75 CA3080 — .95 LM537 — 2.50 LM553 - 2.50 LM555 — .49 LM5G6 — .85 560 — 2.00

565 - .95

566 - '

567

702 —

703

709 —

710 —

74 7

.50

.30

- 2.50

-M13101456 — .9b 1458- .50 3900 — .85 8038CC - 3.90 791 - 1.95 4136 -.95

UP TO 25% OFF^

YOUR OWN TRS-80 SYSTEM AT TREMENDOUS SAVINGS

DISK DRIVES IN STOCK/

OTRS-80 Complete System

Includes: CPU/Keyboard, Power Supply, Video Monitor, Cassette Recorder, Manual, and Game Cassette.

Q Line Printer ©Mini Disk System QC-10 Cassettes ©Verbatim Diskettes

REG.

OUR

ITEM

PRICE

PRICE

Level II—4k

$619.00

$575.70

Level II—16k

$849.00

$789.60

Expansion Interface

$299.00

$278.00

Mini Disk Drivo

$ 495 00

$ 38500

Centronics 779 Printer

$1599.00

$1175.00

Centronics 101 Printer

$1595 00

$1400 00

Anadex DP-8000 Printer

$1295 00

$ 99500

Memory Kit-(16K) FREE installat

ON $ 149.00

$ 98.00

Verbatim Diskettes ea

$ 5 95

$ 4 95

3

$ 17 89

$ 1200

10

$ 59.00

$ 37.50

C-10 Cassettes 5

$ 4 95

S 450

25

$ 2475

S 1875

Paper (9V2 x 11 lanfold.

3500 sheets)

C A 1

$ 35.00

$ 29.95

oALl

Centronics 730

$850.00

Same as Line Printer II

TRS—80 MODEL II

$3626.00

• 64KRAM

• '/2 MEG DISK

VR Data's 1 st Drive

$899.00

ADDITIONAL DISK DRIVE (

1ST)

$1069.50

ADDITIONAL DISK DRIVE (2ND + 3RD)

$ 540.00

\^@adau

777 Henderson Boulevard N-6 Folcroft Industrial Park Folcroft PA 19032 (215) 461-5300

TOLL FREE

1-(800) 345-8102 Orders on

FOREIGN and DOMESTIC DISTRIBUTORSHIPS AVAILABLE

MINI DISK DRIVES NOW $385

Over $100 less than Radio Shack's !

There are new developments every day— write or call for the latest information.

ly!

If 1 I I I I I I 111 111 T I I I I I I I I T 1 TT» n ' 111

228 BYTE February 1980

Circle 179 on inquiry card.

Moonshadow Text Formatter for UCSD Pascal™ Systems

The UCSD PascafM system contains a screen-oriented text editor which is convenient, but which is not suited to word processing. It cannot underline, paginate automatically, or perform other essential text-processing functions. The Moonshadow Text Formatter (MTF) from Merrimack Systems solves this problem.

With the Moonshadow Text Formatter, documents produced with the screen editor are postprocessed to provide these missing functions. It takes standard Pascal text files, operates on them, and sends fully formatted text output to the console display, a printer, or a disk file.

Moonshadow Text Formatter provides, in addition to a full range of formatting functions, advanced features including the comDination of files into one document, variables in text (for form letters), and output character translation.

The Moonshadow Text Formatter is written in UCSD PascalTM, and is available for North Star Apple II, LSI-II. and 8080/Z80 systems with IBM Format 8" floppy disks.

All this for S99.00 from

Merrimack Systems

POB 5218

Redwood City, CA 94063

(415)365-6281

California residents should include 6% sales tax. Also available: North Star Pascal personalization for SOL/SOLOS — just transfer three files and you're up with Pascal. $25.00

New from Vantage Data Products

550 West 200 South Suite8

■Provo.Utah 84601 (801)377-6687

■ $ ■'-; it.,%

Communications/Control CPU Card

« CPU-Z-801KRAM

16 bit interval timerand interrupt EPROM* 2708 standard (2716 optional)

•Serial Communications-RS-232 interface,

UART Complete MODEM capability, programmable baud rates, etc.

•Parallel I/O -16 bits in (TTL), 16 bits Out (TTL)

•Power - on and external reset 'EPROM not included

$195 assembled, tested, with warranty and documentation

Immediate delivery from stock!

All orders shipped prepaid

MC, VISA, phone orders welcome

Utah residents add 4Wsales tax

STATISTICAL DATA

DATABANK programs contain 10 years of monthly statistical data on ten related subjects. Information is the most current available. Each cassette is date stamped. Includes graphs, tables, trends, comparisons, update routine, and external input.

Programs available for TRS-80 LS, 16K

* General Economy

* Manufacturing & Trade

* Industrial Production

* Money & Credit

* Money Rates & Yields

* Commodity Spot Prices

* Mortgage Terms & Yields

* Foreign Exchange Rates

* Energy Production

* Petroleum Production

$29.95 each 3 for $84.95

Cassette storage album included with order for six or more programs.

jllfc DATABANK POB 9283 HIP Ft Lauderdale, FL 33310

Circle 180 on inquiry card.

Circle 181 on inquiry card.

Circle 182 on inquiry card.

16K STATIC MEMORY (RAM)

250 nsec Access Time, Assembled, tested, and Guaranteed. $300.00

Fully Static - TMS 4044

S-100 Bus- Buffered lines, Dip Sw address in

2, 8K blocks4K incr., Write Protect, Phantom

disable. Battery backup, fully Socketed.

Bank Select - Port 40 H (Cromemco Software

Comp.J, 80H or COH.

Guarantee - One full year. To order, call for

Visa, M.C., or C.O.D. ($4 fee.) Personal check

o.k. M.O. speeds shipping. Stock to 72 hour

delivery. Illinois residents add 5'/4% tax.

S. C. DIGITAL

P.O. Box 906, Aurora, IL 60507 Phone: (312) 897-7749

DISCOUNT PRICES

NORTH STAR

APPLE II

POLYMORPHIC

INTERACT

HAZELTINE

SOROC

CENTRONICS

MICROTEK

INTERTUBE

& Others

Call for Prices (301)694-8884

FREDERICK COMPUTER PRODUCTS

Municipal Airport Frederick, MD. 21701

SUPPLIES

• FLOPPY DISKS, MINI OR STANDARD MEMOREX OR 3M

■ 3M DATA CARTRIDGES DC3D0A, DC100A

■ 3M DIGITAL CASSETTES

• 3M OR MEMOREX AUDIO CASSETTES. C-60

■ 3M DISK CARTRIDGES

WE OFFER: •COMPETITIVE PRICING •IMMEDIATE DELIVERIES

(Any Quantity) • UNCONDITIONAL GUARANTEE

BETA BUSINESS SYSTEMS

8369 VICKERSST.. #G ^^» SAN DIEGO, CA 921 1 [7)41 565-1505

Circle 183 on inquiry card.

Circle 184 on inquiry card.

Circle 185 on inquiry card.

H9 OWNERS!

Now you too can have graphic capabilities similar to those of the TRS-80 with GRAFIX. No modification to existing circuit boards is required. GRAFIX simply plugs into existing IC sockets.

Comes with complete instructions. Full 6 month warranty.

Kit $59.95

Assembled and tested $69.95

Northwest Computer

Services, Inc. 8503 N.E. 30th Avenue Vancouver, WA 98665

Texas Instrument 99-4 Computer

$ 990.

TI 810 Printer

$1590.

Centronic Printers:

730-1 Parallel

$ 799.

730-2 Serial

$ 859.

779-1 Friction Feed

$ 959.

779-2 Tractor Feed

$ 999.

Comprint 912 Par

$ 475.

912 Ser

549.

Anadex with Par & Serial Interlace

* 799.

Commodore Business Machines:

PET 2001-BK Computer

$ S95.

PET2001-16K

$ 895.

PET2001-32K

$1090.

PET 2022 Trac. Fed Printer

$ 899.

PET 2023 Frig. Fed

$799.

$75. Free Soitware with PET Machines

lntertec Superbrain

North Star Computer and Ace.

Save $ Save $

Display Terminals:

Intertube II

$ 775.

Hazeltine 1400

$ 690.

1410

$ 785.

1500

$ 990.

Immediate Delivery from Stock.

Multi-Business Computer System

28 Marlborough Street

Portland, Conn. 06480

(203) 342-2747

SEARCHING THROUGH YOUR ENTIRE

NORTH STAR

BASIC PROGRAM LISTINGS.

WITH OUR NEW "SCAN" COMMAND YOU CAN INSTANTLY DISPLAY OR PRINT

JNES THAT CONTAIN A SELECTED VARIABLE.

• ALL REFERENCES TO ANY LINE NUMBER

• ALL OCCURRENCES OF ANY CHARACTER. NUMBER, LINE NUMBER. GROUP OF CHARACTERS OR ANYTHING THAT IS CONTAINED IN ANY BASIC LINE.

This is not one or those ■'funny programs written in BASIC." It is » machine language addition to BASIC thai resides completely within NORTH STAR BASIC. It will not eltecl normal BASIC qi DOS. Il is sell loading and can be loadec separately lo operate with BASIC of saved along with BASIC as a copy ol BASIC wilh the "Scan" command. Does nol change memory available to BASIC Easy lo under

• Available for version 6 as well as 14 digit basic

• Slate your version when ordering

• Dealer inquiries invited

PHONE ORDERS ACCEPTED

ORDER TODAY USE YOUH VISA OR MASTERCHARGE C

ONLY $275°°-°*

H

ELECTRONIC TECHNICIANS SOFTWARE SERVICES 1072 CASITAS PASS RD. CARPINTERIA. CA 93013

805-684-2541

Circle 186 on inquiry card.

Circle 188 on inquiry card.

Circle 189 on inquiry card.

!M:l:VA7M:l

ELECTRONICS

America's Largest Mail-Order Computer Store

74L$

1.25 .39

| Order by Cat No.

NO. PRICE

74LS00 .28

74LS01 .19

74LS02 .29

74LS03 .19

74LS04 .89

74LS05 .35

74LS08 .29

74L$09 .25

74L$10 .29

74L$11 .59

74LS12

74LS13

74LS14

74LS15

74LS20

74LS21

74LS22

74LS26

74LS27

74LS28

74LS30

74L532

74LS33

74LS37

74LS38

74L$40

74LS42

74LS47

74LS48

741551

74LS54

74LS55

74LS73

74LS74

74LS75

74LS76

74LS83

74LS85

74L$B<>

74L590

74LS92

74LS93

74LS95

741596

74LS107

999 and type NO. PRICE

74LSI57 74LSI58 74LSI60 74LS161 74LSI62 74LSI63 74 LSI 64 74 LSI 65 74LS168 74LSI69 74 LSI 70 74LS173 74LS174 74LS175 74LS181 74LSI90 74 LSI 91 74LS192 74LS193 74LS194 74LS195 74LS196 74 LSI97 74LS221 74LS240 74LS241 74LS242 74LS243 74LS244 74LS247 74 L$ 24(1 74LS251 74LS253 74LS257 74LS25H 74LS259 74LS260 74LS261 74LS266 74LS273 74LS275 74LS279 74LS283 74LS293 74LS295

1.45

1.10

1.25

2.25 1.10 1.10 1.10 1.10 1.10 1.10 .89 1.65 1.25 4.50 2.40 1.50 2.50 2.60 1.10 1.10 1.99

1.99

1.75

1.95 .99

TTL

Order by Cat No. 999 and type

7402

.18

74120

7403

.10

74121

7404

.11

74122

7405

.19

74123

7406

.19

74125

7407

.19

74126

7408

.19

74128

7409

.19

74132

7410

.19

74136

7411

.25

74139

7412

.25

74141

7413

.35

74143

7414

.60

74145

7416

.19

74148

7417

.25

74150

7420

.19

74151

7422

.79

74153

7423

.22

74154

7425

.25

74155

7426

.35

74156

7430

,19

74157

7432

.25

74160

7437

.25

74161

7430

.25

74162

74 LSI09 74LS112 74LS113 74LSI14 74LSI22 74LS123 74LS124 74LSI 25 74LSI26 74LS132 74 LSI 38 74 LSI 39 74LS145 74 LSI 51 74LS153 74 LSI 54 74LS155 74LS156

.79 1.79

74LS298

74LS365

74LS366

74LS367

74LS368

74LS373

741.5374

74LS377

74LS378

74LS386

74LS393

74LS395

74LS399 2.95

74LS424

74LS668

74LS670

81LS 96

OILS 97

3.05 1.95 3.90 1.25

1.45

1.25 2.49 1.45 1.55

7440 7441 7442 7443

7453 7454 7460 7470 7472 7473 7474 7475

7480 7481

7482 7483 74B5 74B6 7489 7490 7491 7492 7493

BSE

Wmjm

74176 74177 74179 74780 74181 74182 74184 74185 74190 74191 74192 74193

74197 74198 74199 74221 74251 74273 7427B 74279 74298 74365 74366 74376 74160

MICROPROCESSORS]

Order by Cat No. 999 and type \

TYPE NO. PRICE

Z80 A

12.75

1802

16,50

6502

14.50

6800

6.50

8035

11.75

8080 A

6.60

8085

15.95

TMS 9900

49.00

CALL TOLL FREE:

(800) 423-5387 USA

IN CALIF:

(800) 382-3651

r* 6 \

bbb:

i

LUUAL « V

(213) 88

MICROPROCESSOR

SUPPORTS

Order by Cat No. 999 and type

NO.

PRICE

NO.

PRICE

8212

2.95

280A CTC

13.95

8214

4.95

Z80A 5I0

55.00

8216

2.60

8224

3.95

6810

5.95

8226

3.95

6820J6520

6.96

8228

5.95

6821

6.95

8238

6.75

6828

11.95

8251

6.95

6850

9.95

8253

11.50

6852

6.50

8255

7.95

6860

9.95

8257

15.95

8259

18.95

1822

18.95

8279

9.50

1852

7.50

8271

17.50

1854

13.95

Z8OA-PI0 13.95

1861

15.95

RAMS/EPROMS

Order by Cat No. 999 and type

TYPE NO.

PRICE

1101

.79

2101-250

1.95

2101-450

1.25

21L02-650

.79

2IL02-450

1.10

21L02-250

1.25

2111-400

2.95

2114-300

7.25

2114-200

9.75

4027P-2

3.90

TMS 4045-450

6.50

TMS 4045-300

7.25

41 16-300

11.65

4116-250

12.75

4116-200

13.75

4116-150

14.90

9050 CDC

4.50

91L02-450

.79

1702 A

4.25

TMS 2532

86.00

2708

9.15

2716

27.00

16K MEMORY

ADD-ON

S75

2 for S140

For TRS-S0, Apple. Exidy

Installs

n minutes, no special

tools required. Complete with

detailed

instructions. Wt 4 oz.

Col No.

Description

1156

For TRS-H0 keyboard

1156A

TR5-80 without buf

fered cable

11568

TRS-80 with buffered

cable

1156C

For Apple

11.i6D

For Exidy Sorcerer j

HOW IO ORDER: Pay by check. Mulercharge, Visa, or COD. CliarKL- orders please include eipiralion dale. Foreign pay in U.S. fundi. Order by phone or mail, 01 at OUt retail. MINIMUM ORDER Sin. please Include phone number and mag? a/inelisiue you are ordering (mm. Prices valid Ihrn l.isl da\ ol cmer date. SHIPPING: USA:: add $2.00 for the first J lbs. For ground add !!5< lot adill'l lb. for air add Tic lor ailrit'l lb. FOREIGN: surface: add S.i.tMi tor lirsl I tbs. r.tK per ailill'l lb. Air: add SM.00. for lirsl 2 lbs. $i lor each addl'l lb. COFJs SI addl'l. Guaranteed satisfaction lor 121) days ■ b.ick! Nol rc

s.bl,.

typoi

. Snme items subject In prior sale. We reserve (be right lo limit quantities, SEND FOR FREE CATALOG FEATURING: Computers .inrl accessories, disk drives, printers, integrated citicomlucli.rs.

Thev

19511 Business Center Dr. Dept. B2 Northridge, Ca. 91324

BUILD YOUR OWN LOW COST MICRO-COMPUTER

POWER SUPPLIES

FOR S-100 BUS, FLOPPY DISCS, ETC.

POWER TRANSFORMERS (with mounting brackets)

ITEM NO.

USED IN KIT NO.

PRI. WINDING TAPS

SECONDARY WINDING OUTPUTS 2x8 Vac 2x14 Vac 2x24 Vac

SIZE W x D x H

UNIT PRICE

T1 T2 T3

T4

0V, 110V, 120V 0V, 110V, 120V 0V, 110V, 120V 0V, 110V, 120V

2x7.5A

2x12.5A

2x9A

2x4A

2x2.5A 2x3.5A 2x2.5A

2x2.5A 2x3A

3%"x35/8"x31/8" 3%"x43/8"x3Va" 3%"x43/8"x3Vs" 3%"x35/e"x3V8"

21.95 27.95 29.95 21.95

POWER SUPPLY KITS (open frame with base plate, 3 hrs. assy, time)

ITEM USED FOR @+8Vdc @-8 Vdc @ + 16 Vdc (5j-16Vdc (S + 28Vdc

SIZEWxDxH UNIT PRICE

KIT1 15 CARDS SOURCE 15A

KIT 2 SYSTEM SOURCE 25A

KIT 3 DISC SYSTEM 15A

KIT 4 DISC SOURCE 8A

1A 1A

2.5A 3A 2A

2.5A 3A 2A

4A 5A

12"x6"x4%" 12"x6"x4%" 14"x6"x4%" 10"x6"x47/b"

51.95 58.95 66.95 49.95

EACH KIT INCLUDES: TRANSFORMER, CAPACITORS, RESIS., BRIDGE RECTIFIERS, FUSE & HOLDER, TERMINAL BLOCK BASE PLATE, MOUNTING PARTS AND INSTRUCTIONS.

DISC DRIVE POWER SUPPLY "R3" assy. & tested, open frame, size: 9" (w> x 5" (D) x 5" (H) 59.95

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: S4.75. FOR EACH POWER SUPPLY: S5.00 IN CALIF. S7.00 IN OTHER STATES. CALIF. RESIDENTS ADO 6% SALES TAX. OEM WELCOME.

MAILORDER:

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

230 BYTE February 1980

Circle 190 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 world use this board with complete satisfaction. Puts 16K of software on line at ALL TIMES! Kit features a top quality soldermasked and silk-screened PC board and first run parts and sockets. Any number of EPROM locations may be disabled to avoid any memory conflicts. Fully buffered and has WAIT STATE capabilities.

OUR 450 NS 2708'S ARE $8.95 EA. WITH PURCHASE OF KIT

ASSEMBLED

AND FULLY TESTED

ADD $25

8K LOW POWER RAM KIT-S 100 BUSS

SALE

■■■ ■ -: ■ ■ ■ ■ . ■' .:■ :

$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 FULLY BURNED IN ADD $30

ALL ASSEMBLED BOARDS ARE TESTED AT 4MHZ.

Support IC's (TTL & Regulators)

$9.75 Bypass CAP'S (Disc & Tantalums)

$4.50

16K STATIC RAM KIT-S 100 BUSS

16K STATIC RAM SS-50 BUSS

PRICE CUT!

nx%r^3sssr

$259

KIT

.^iiiiiiiiiiiLiiiM^

PRICE CUT!

flHHUB

1. Addressable as four separate 4K Blocks.

2. ON BOARD BANK SELECT circuitry. (Cromemco Standard!}. Allows up to 512K on line!

3. Uses 2114 (450NS) 4K Static Rams, 4.- ON BOARD SELECTABLE WAIT STATES.

5. Double sided PC Board, with solder mask and silk screened layout. Gold plated contact fingers.

6. All address and data lines fully buffered.

7. Kit includes ALL parts and sockets.

8. PHANTOM is jumpered to PIN 67.

9. LOW POWER: under 1.5 amps TYPICAL from the +8 Volt Buss.

10. Blank PC Board can be populated as any multiple of 4K.

«;■

BLANK PC BOARD W/DATA-$33 LOW PROFILE SOCKET SET-$12

SUPPORT IC'S & CAPS-$19.95 ASSEMBLED & TESTED-ADD $30

FULLY STATIC

AT DYNAMIC

PRICES

leBiiiiiEiiiiiii iiiiniiiiiiiiii

:

FOR SWTPC 6800 BUSS!

OUR #1 SELLING RAM BOARD!

KIT FEATURES:

1. Addressable on 16K Boundaries

2 Uses 2114 Static Ram

3. Runs at Full Speed

4. Double sided PC Board Solder mask and 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—$12 SUPPORT IC'S AND CAPS—$19.95

ASSEMBLED AND TESTED - $30

PROC TECH. QUITS THE MICROPROCESSOR BUSINESS!

FACTORY CLOSE OUT - SPECIAL PURCHASE!

#16KRA

16K S-100 Dynamic Ram Board $149.95

We purchased the remaining inventory of PT's popular 16K Ram Board when they recently closed their plant. Don't miss the boat! These are brand new, fully tested, ASSEMBLED and ready to go. All are sold with our standard 90 day limited warranty!! Orig. $429 each! 72 Page Full Manual, Included Free!

Perfect for OEM's

S-100 Z80 CPU CARD

*159

95

WIRED! NOT A KIT!

4 MHZ

Z-80 PROGRAMMING MANUAL

By MOSTEK, or ZILOG. The most detailed explanation ever on the working of the Z-80 CPU CHIPS. At least one full page on each of the 158 Z-80 instructions. A must reference manual for any user of the Z-80. 300 pages. $12.95

ASSEMBLED AND TESTED! READY TO USE! Over 3 years of design efforts were required to produce a TRUE S-100 Z80 CPU at a genuinely bargain price! BRAND NEW!

FEATURES:

+ 2 or 4 MHZ Operation * Generates MWRITE, so no front panel required. • Jump on reset capability. ■* 8080 Signals emulated tor S-100 comparability * Top Quality PCB. Silk Screened. Solder Masked Gold Plated Contact Fingers

c, LOW POWER - 250NS 8 FOR

sM-fc' 2114 RAM SALE! $55

4K STATIC RAM'S. MAJOR BRAND, NEW PARTS. These are the most sought after 2114's, LOW POWER and 250NS FAST. SPECIAL SALE: $750 ea. or 8 For $55

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 Amplitude Control, 16 Bit Envelope Period Control, 2-8 But Parallel /O. 3 D to A Converters, plus much more! All in one 40 Pin DIP. Super easy to interface to the S-100 or other busses. SPECIAL OFFER: $14.95 each Add $3 for 64 page Date. 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 under $15 add 75C handling. No C.O.D. We accept Visa and MasterCharge. Tex Res. add 5% Tax. Foreign orders (except Canada) add 20% P & H. 90 Day Money Back Guarantee on all items.

NOT ASSOCIATED WITH DIGITAL RESEARCH OF CALIFORNIA, THE SUPPLIERS OF CPM SOFTWARE.

Circle 191 on inquiry card.

BYTE February 1980 231

g£

/MICRO

BUSINESS WORLD

Immediate response to your orders (verbal or written). Phone (213) 371 -1660

Apple II personal computer.

16K Regular or Plus

$ CALL

$ CALL

Disk II with controller Disk II without controller $ CALL PASCAL Language Card $ CALL CALL for our lowest prices ever. We carry all peripherals and interface boards for the APPLE. European versions available.

DYSAN DISKETTES

THE CADILLAC OF THE

FLOPPY DISKS AT LOW LOW PRICES

8" (BOX OF 10)

3740/1 sgl side/

sgl density 4.00 ea 3740/1D sgl side/

dbl density 6.50 ea 5" (BOX OF 5 ) 104/1 soft sector 4.00 ea 107/1 10 sectors 4.00 ea

105/1 16 sectors 4.00 ea

For each 2 boxes ol 8" or 4

boxes ol 5" you gel one

plastic storage case, but

hurry— supply is limited

EPSON (A SEIKO COMPANY) TX-80 Printer with 64 graphics characters 7x5 dot matrix (7x6 in graphics) Double width characters

ATARI 800 Compute 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 $ CALL

ATARI 400gS}ocSuter

Packed with: Computer Console, Basic Language Cartridge. Power Supply, TV Modulator, and all

Books and Manuals $ CALL ATARI Program Recorder $ CALL

ATARI Software. Roms.Cassettes* CALL ATARI Expansion Memory: $ CALL

8K Module or 16K Module $ CALL CALL for our lowest prices ever.

Plastic Floppy Disk Holder

(up to 10) 8" $3.95 (up to 10) 5" $3.25

16K RAM setof8 4116's

200 ns or better $65.00

Tractor Feed Model $695.00

Friction Feed Model $595.00

TRS80 Interfaces Cable $50.00

Pet Interface & Cable $80.00

APPLE Interfaces Cable $80.00

RS232 Interfaces Cable $80.00

Prices subject to change without notice. VISA and MASTER CHARGE WELCOME (Add 3%) Allow 2 weeks for cashiers check to clear. 4 weeks for personal checks. Add 2% for shipping and handling. Calif, residents add 6% sales tax. U.S. and International dealer inquiries invited.

ZENITH DATA SYSTEMS:

Smart Video Terminal

Z-19 has a Z80 Microprocessor. Numeric Keypad and 8 function key $895.00

Z-89 Computer System:

includes: Z19 Display, a built in 5 V Floppy Disk, 2 serial ports, and 16K of memory. 2295.00 48K Memory version 2595.00

/VIICRO

BUSINESS WORLD

15818 Hawthorne Boulevard Lawndale, California 90260 (213)371-1660

AIM 65

AIM 65 is fully assembled, tested and warranted. With the addition of a low cost, readily available power supply, it's ready to start working for you. It has an addressing capability up to 65K bytes, and comes with a user-dedicated 1K or 4K RAM.

• Thermal Printer • Built-in Expansion Capability

• Full-Size Alphanumeric Keyboard • TTY and Audio Cassette Interfaces

• True Alphanumeric Display • ROM Resident Advanced Interactive Monitor

• Proven R6500 Microcomputer System Devices • Advanced Interactive Monitor Commands

PRICE: $37&ee

(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 added to our mailing list, or U.S. residents send $1.00 (International send $3.00 U.S.) for airmail delivery of our complete catalog. circ|e ig3 on inquiry card

PRICE: $129.00

We also carry the SYM-1 Microcomputer with manuals $269.00

VAK-1 MOTHERBOARD

• Designed specifically for use with the AIM-65, SYM-1, and KIM-1 microcomputers

• Standard KIM-4* Bus

• Fully buffered Address and Data Bus

• Provides 8 expansion board slots

• Complete with rigid card-cage

• All IC's are socketed

• Provides separate jacks for one audio-cassette, TTY, and Power

• Completely assembled (except for card-cage)

We manufacture a complete line of high quality expansion boards. Use reader service card to be added to our mailing list, or U.S. residents send $1.00 (International send $3.00 U.S.) for airmail delivery of our complete catalog. 'Product of MOS Technology

RNB> ENTERPRISES

INCORPORATED 2967 W. Fairmount Avenue • Phoenix, AZ 85017 • (602) 265-7564

232 BYTE February 1980

Circle 194 on inquiry card.

When the people

behind the products count!

(Formerly the CPU Shop)

TM

X

SPECIALS

Regular Price

32 K, quad-density, assembled and tested $2564

32 K« quad-density, assembled and tested $3215

$1895 $ 149

ComputerCity Sampler Disk Drives

When you're ready to add disk storage to your TRS-80*, we're here to help. Our CCI-100"'and-200"'drives offer more capacity than Radio Shack 35-Track(85K Bytes) drives. These drives are fully assembled, tested and ready to plug-in the moment you receive them. They can be intermixed with each other and Radio Shack drives on the same cable. 90 day warranty. CCI-100"'' 40 Track (102K Bytes) $399.00 CC1-200"' 77 Track (197K Bytes) $675.00

Printers

Letter Quality High Speed Printer

NEC Spinwriter: Includes TRS-80* interface software, quick change print fonts, 55 CPS, bidirectional, high resolution plotting, graphing, proportional spacing and

tractor feed assembly. 90 day warranty $2979.00 Also: Centronics, Paper Tiger, HI Plot Digital Plotter 16K Memory Op-grade Kits

Fast and uitrareliable $99.00

DISK OPERATING SYSTEMS NEWDOS by Apparat+ $49.95

NEWDOS "PLUS" by Apparat"1" $99.95

DOS 3.0 by the original author of 2.1 $49.95

DISKETTE TRS-80*

BUSINESS SOFTWARE BY SBSG

Free enhancements and upgrades to registered owners for the cost of media and mailing. 30 day free telephone support. User reference on request. Fully Interactive Accounting Package: General Ledger,

Accounts Payable, Accounts Receivable and Payroll.

Report generating.

Complete Package (requires 3 or 4 drives) $475.00

Individual Modules (requires 2 or 3 drives) $125.00 Inventory II: (requires 2 or 3 drives) $ 99.00

Mailing List Name & Address II

(requires 2 drives) $129.00

Intelligent Terminal System ST-80 III: $150.00

The Electric Pencil from Michael Shrayer $ 150.00 File Management System: $ 49.00

Budget Control Program II by CSA $ 49.95

Cash Register System II by CSA $ 99.00

(ComputerCity

A division of CPU Industries, Inc.

1175 Main Street, Dept. B-2Charlestown, MA 02129 ,

Hours: 10AM - 6PM (EST) Monday - Saturday For detailed information, call 617/242-3350 Massachusetts residents add 5% Sales Tax

TM CCI-lOO &-200 are ComputerCity Inc. trademarks

"TRS-80 is a trademark of Radio Shack, a Tandy Corporation tRequires Radio Shack TRSDOS* Prices subject to change without notice

TO ORDER CALL TOLL FREE 1-800-343-6522

Massachusetts residents call 617/242-3350 Retail Store Locations:

175 Main Street, Charlestown, MA

K Mart Plaza, Manchester, NH

50 Worcester Road(Rt.9), Framingham, MA

165 Angell Street, Providence, Rl

Visa and Master Charge accepted

Franchise and dealer inquiries invited

Circle 195 on inquiry card.

BYTE February 1980 233

Circle 197 on inquiry card.

WAMECO

THE COMPLETE PC BOARD HOUSE EVERYTHING FOR THE S-100 BUSS

INTRODUCTORY SPECIAL IOB-1 SERIAL/PARALLEL INTERFACE BOARD

* TWO PARALLEL DATA PORTS PROGRAMMABLE USING AN 8255 WITH SEPARATE HANDSHAKING.

* ONE SERIAL PORT USING AN 8251 WITH PROVISIONS FOR PARITY, STOP BIT AND CHARACTER LENGTH. BAUD RATES 110 TO 9600 BAUD. OUTPUTS RS232, TTL AND CURRENT LOOP.

* KANSAS CITY STANDARD CASSETTE INTERFACE, 300 BAUD FOR USE WITH THE SERIAL INTERFACE.

* STATUS MAY BE POLLING SOFTWARE OR VECTURED INTERRUPTS.

PCBD (SPECIAL FEB. PRICE) ......$29.95 AFTER FEB. ......$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 4-8 WEEK DELAYS REQUIRED FOR OTHERS.

W77?C

iflC. WAMECO INC. 111 GLENN WAY "8, BELMONT. CA 94002 (415) 592-6141

>i

CALIFORNIA COMPUTER SYSTEMS

16K RAM BOARD. Fully buffered addressable in 4K blocks. IEEE standard for bank addressing 2114's.

PCBD $ 26.95 Kit 450 NSEC ....$249.95

PT-1 PROTO BOARD. Over 2,600 holes 4" regulators. All S-100 buss functions labeled, gold fingers. PCBD $25.95

PT-2 PROTO BOARD. Similar to PT-1 except setup to handle solder tail sockets. PCBD ...$25.95

CCS MAIN FRAME. Kit (S-100) $349.95

APPLE EXTENDER. Kit $22.95

APPLE IEEE INSTRUMENTATION INTERFACE KIT 7490. Kit $275.00

ARITHMETIC PROCESSOR FOR APPLE 7811A. Kit $350.00

APPLE ASYNCHRONOUS SERIAL INTERFACE 7710A. Kit $89.95

APPLE SYNCHRONOUS SERIAL INTERFACE

7712A. Kit $89.95

ALL OTHER CCS PRODUCTS AVAILABLE

==/n

PB-1 2708 & 2716 Programming Board with provisions for 4K or 8K EPROM. No external supplies require textool sockets. Kit $129.95

CB-1A 8080 Processor Board. 2K of PROM 256 BYTE RAM power on/rest Vector Jump Parallel port with status. Kit ....$129.95 PCBD $30.95

VB-3 80x55 VIDEO BOARD.

Graphic included TBD

IO-4 Two serial I/O ports with full handshaking 20/60 ma current loop: Two parallel I/O ports. Kit $130.00 PCBD $26.95

VB-1B 64 x 16 video board, upper lower case Greek composite and parallel video with software, S-100. Kit $125.00 PCBD $26.95

CB-2 Z80 CPU BOARD. Kit $185.95

AIO APPLE SERIAL/PARALLEL $159.95

ALL OTHER SSM PRODUCTS AVAILABLE

W7T7C

inc.

WAMECO INC.

FDC-1 FLOPPY CONTROLLER BOARD will drive shugart, pertek, remic 5" & 8" drives up to 8 drives, on board PROM with power boot up, will operate

with CPM™ (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 interrupts. Software programmable. PCBD $23.95

EPM-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 of 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

8080A $9.95 2708 $9.49

8212 2.49 2114 (450 NS) low pwr 5.99

8214 4.49 2114 (200 NS) low pwr 6.99

8224 3.49 2102A-4L 1.20

m&

(415) 592-1800 P. O. Box 424 • San Carlos, California 94070

Please send for IC, Xistor and Computer parts list

FEB. SPECIAL SALE ON PREPAID ORDERS

(Charge cards not included on this offer)

IOB-1 SERIAL/PARALLEL INTERFACE BOARD. Two parallel ports 8255, one serial port 8251, one Kansas City standard cassette.

PCBD (Introductory) $24.95

UIKOS PARTS ASSORTMENT WITH WAMECO AND CYBERCOM PCBDS MEM-2 with MIKOS s7 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 *2 8080A CPU $ 94.95

QM-12 with MIKOS *4 13 slot mother

board $ 89.95

RTC-1 with MIKOS *5 real time clock $ 54.95

EMP-1 with MIKOS *10 4K 1702 less

EPROMS $ 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 s14 all parts

for front panel $134.95

MIKOS PARTS ASSORTMENTS ARE ALL FACTORY MARKED PARTS. KITS INCLUDE ALL PARTS LISTED AS REQUIRED FOR THE COMPLETE KIT LESS PARTS LISTED. ALL SOCKETS INCLUDED.

VISA or MASTERCHARGE. Send account number, interbank number, expiration date and sign your order. Approx. postage will be added. Check or money order will be sent post paid in U.S. If you are not a regular customer, please use charge, cashier's check or postal money order. Otherwise there will be a twoweek delay for checks to clear. Calif, residents add 6% tax. Money back 30-day guarantee. We cannot accept returned IC's that have been soldered to. Prices subject to change without notice, sio minimum order. SI.50 service charge on orders less than $10.00.

234 BYTE February 1980

Circle 196 on inquiry card.

TRS-80 COMPATABLE DISK DRIVES

The largest

family of

disk drives

from the

largest a

supplier,

drives come I

complete 1

with power 1

supply and I

... ■. . , \

cabinet

18 ■ 'W9BM0B

■ ■,:

■ : ■ ■.■ ■ .

TF-1 Pertec FD200, 40 track

TF-3 Shugart SA400. same as tandy.

B51 MPI 851, 40 track

TDM Dual Head, 35 track

$382 $389 $379 $499

220 versions available.

NOW! SUPER & MAX DISKS

SUPER: 77 tracks on one 5:A diskette that's 197K of storage with New DOS+ $695

MAXI DISK I: 10 Megabyte hard disk with 5fixed 5 removable with controller $6299

MAXI DISK II: 9.8 Megabyte on one disk using Winchester

technology. Unit is sealed in unit for added

protection $5349

SOFTWARE

NEW DOS+ over 200 modifications, corrections and enhancements to TRS DOS Includes utilities.

35 Track NEWDOS+ $99

40 track NEWDOS+ $110

AJA Word Processor $75

AJA Business Program $250

Racet Infinite Basic $49.95

Disk Drive Alignment Program $109

Radex Data Base $99.95

Electric Pencil $150

BASE 2 ONLY

$599.

LINE PRINTERS

ST

The new base 2 printer, prints 60 Ipm, 80 & 132 col. formats. It has tractor feed w/RS232, IEEE & centronic interface.

DP800 ANADEX 80 column, 112 cps $950

LP779 Centronics 779 $1099

LP730 Centronics 730 $950

LP700 Centronics 700 $1495

LP701 Centronics 701 $1759

LP702 Centronics 702 $1895

Spin-1 Spinwriter $2499

MOD II DISK DRIVES NOW AVAILABLE

ADD-ON DRIVE FOR ANY MICROCOMPUTER

Pertec FD200 ...

Pertec FD250 (dual head) J282

Shugart SA400 (unused) *349 I

Shugart SA800 $286

MPI B51 $479

MPI B52 (dual head) $279

$349 I

NEW PRODUCTS

Small Systems Interface (RS232) $49.95

Expansion Interface W32K $499.95

AC Line Filter $18.95

AC Isolater (6 connecters) $45.95

Mode M $179.95

Verbatim 5'A Diskettes $3.39

16 Key Pad Kit (no soldering) $68

16K Memory (Keyboard) $89

16K Expansion (Interface) $86

ALL PRICES CASH DISCOUNTED • FREIGHT FOB/FACTORY

»in

/MICROCOMPUTER

TECHNOLOGY INCORPORATED

3304 West MacArthur Blvd

Santa Ana, CA 92704

(714) 979-9923

^^m

i

visa m

master charge] / ,

THE IMTCR8ANK CARD k § j

\

1 m

7310 E. Princeton Ave. Denver, CO 80222 (303) 758-7275

pparat, Inc.

Circle 198 on inquiry card.

Circle 199 on inquiry card.

BYTE February 1980 235

Circle 200 on inquiry card.

computer products,

11542-1 KNOTT ST.

GARDEN GROVE,

CA 92641

(800)854-6411

(714)891-2663

MICROBYTE 16K RAM BOARD

• FULLY S-100 COMPATIBLE

• USESLO-PWR 4KX1, MM5257'S

•2MHZ0R4MHZ •4KBANK

ADDRESSABLE •EXTENDED MEMORY

MANAGEMENT •NO DMA RESTRICTIONS •ASSEMBLED & TESTED 2MHZ$250-4MHZ$265

MICROBYTE 32K RAM BOARD

REGULATORS

320T-5.. 320T-12. 340T-5. . 340T-12. 78H05 . . 78L12 ..

.90 .90 .80 .70 .4.75 . .35

• FULLY S-100 COMPATIBLE

• USESLO-PWR 4KX1,MM5257's

•2MHZ0R4MHZ

• BANK ADDRESSABLE

• EXTENDED MEMORY MANAGEMENT

•8-BIT OUTPUT PORT •NO DMA RESTRICTIONS •ASSEMBLED & TESTED 2MHZ$525-4MHZ$540

MISC. COMPONENTS

IMSAI CONNECTORS

100 PIN-SOLDERTAIL

$3.00 each 10 for $2.75 each

LM339 . .

LM348..

.1

LM377..

.1

LM380..

LM3900.

DM8216.

.2

8080A . .

.4

8251 ...

.5

1-9

70 00 10 80 55 10 50 00

10-99

.65

.92

1.00

.75

.50

2.00

4.25

4.80

100 up

.59 .85

.95

.70

.44

1.90

1.00

4.50

LO-PRO SOCKETS

14 PIN 16 PIN

18 PIN 20 PIN 24 PIN 28 PIN 40 PIN

1-24

.15 .16 .19 .27 .35 .40 .50

25-99 100 up

.14 .13

.15 .17 .25 .31 .33 .46

.14 .15 .23 .27 .29 .41

4116's

(250NS)

ADD ON MEMORY

FOR APPLE, TRS 80,

HEATH, ETC.

8 for $64.00

or

16 for $120.00

SA800 DRIVE

INSTALLED IN DUAL

CABINET W/PWR SUPPLY

ASSEMBLED & TESTED

(1) DRIVE INSTALLED

$695.00

(2) DRIVES INSTALLED

$1125.00

ASK FOR OUR NEW CATALOG

2716's

5-VOLT ONLY 450 NS.

$32.00 ea.

or

8 for $240

ORDERING INFO

NAME, ADDRESS, PHONE

SHIP BY: UPS OR MAIL

SHIPPING CHRG: ADD $2.50

UP TO (5) LBS, CREDIT CARDS

WILL BE CHARGED

APPROPRIATELY

2708's

450NS $8.50

or

8/$60

CERAMIC CAPS

.1 @ 12 VOLTS

10« ea

or

100/$9.00

2114's

LO-PWR 300 NS.

1-16 PCS.

$5.25 ea

17UP $5.00 ea

TERMS

WE ACCEPT CASH,

CHECK, MONEY ORDERS,

VISA & MASTER CHRG.

(U.S. FUNDS ONLY)

TAX: 6% CALIF. RES.

DIGITAL MULTIMETERS

HickokLX303*695°

Sinclair PDM35

Reg. S69.95

$4995,

3%-Digit "-SJS Portable DMM

Tmuraphone

Cordless

Telephone

System

Reg. S89.95 $7495

'/ • Overhead Protected • Battery or AC operation • 3" high LED Display • Auto zeroing

Portable Oscilloscopes/** 15 MHz am ■ g»*F Dual Trace Triggered »« Miniscope WaV

$36995s,Res

Model MS-215

S435.00

15 MHz Triggered Miniscope

Model MS-15 RegS319 00j«eQ95

30 MHz Dual Trace Triggered Miniscope

Model MS-230 R?g S559 00*479^

Logic Probe

■ Compact circuit powered ■ Detects pulses as short as 50 ,isec. DTLTTLHTL'CMOS, compatibility $4495

RC Circuit Box

• 36 resistors (15!! to 10MUI ■ 18 capacitors (100 pt to

Reg S49 95 t^.

includes test leads

Model LP-1

Chess

Challenger 7 *''•:<&■*

Reg S99 95 Mo(je| I ■™cj"u.ji„ $7490 BBC I

Function Generator

Model 2001 Reg. $185.95 S15795

■ Sine-, square-. Iriangle- and separale TTL square wave output ■

Frequency range: IHz-IOOKHz

Portable VOM Multitester

Model $1Q95 VM520 I •»

20K!i VDC 10KS1 VAC

HICKOK

Digital CB In-Line Tester

$16995,

Reg. S399.00

100 MHz 8-Digit Counter

• 20 Hz to 100 MHz MJdel ™*X1S° rS range. LED display "j°J15lL"

• Fully automatic *"J 2/

Logic MonitorTTelephone

Automatically displays static and dynamic logic • Model LM-1 Works with DTL. HTL, SCQ95 TTL. and CMOS • 16

LED display

Attache Style Tool Case

Model TC100 ST

A $27995

Service Master Tool Kit

Model 99-SM S6R9C99S $4750

Weller'-Xcelite"

Model 820 Measures capacitance

from 0.1pF to 1 Farad ■ Resolves to O.lpF ■ 10 ranges for accuracy and resolution ■ A digit easy-to-read LED display ■ 0.5% accuracy

*=S=3V2-Digit0.1% Digital Capacitance Meter Model 3001

• 9 ranges Irom 1999 pF to 199.9 WF 0.1% of reading accuracy „„Reg $-i "7CI

Proto E^B Preassembled r^ei^k Boards

PB-104>Ss|"**499b

Fully assembled breadboard contains lour QT-59S sockets, seven QT-59B bus strips and four 5-way binding posts

Proto Board with Built-in Power Supplies

i129MS&

30 MHz LEADER Dual Trace

$89995

Model LBO-520

Weller'Controlled Output Soldering Station

BSS2MS3 Portable Digital Capacitance Meter ( % .,,

6"x9" 3-Way Speaker

■ 20 oz. ceramic magnet Model BP2000-69TR

$1495ea.

CODEvl-PHONE

Answering

Model 1500 $0*Q95 Call Control ^£f\y^ Reg S349 95 __

*19995

Model 1-1011

t

r^Beckman TECH 310

^130.

WAHL

!^™ Cordless 60 Soldering vw Iron $2995

Model 7800

Thenmcd-Spat

Circuit Tester »2995

Miniature High Fidelity 3-Way Stereo Speakers

$CQ50 Re9 S149.95

Model HF-9

S190.00

y Simpson 461

. Iui(fca^ Complete with nickeliAi:.^L A cadmium batteries, AC charger adapter, test

leads $14995

In-Dash Car Stereos 8-Track Tape Player with AM/FM/MPX Radig_

Model C-777 f

$525o

Cassette Tape Player with AM/FM/MPX Radio

Model K " "~

CAS-888 \ g =

$5750 i^SiS

Tr

BSRX-10

is

Remote Control for Lights & Appliances

•1 Pc S1.ind.itd Starter Kil • One (1) Standard Command Reg £67 95 Console ■ Two (2i Lamp Modules ■ One (I) Apnhanee S7Q50 Module I !7

5 Pc Ultrasonic Starler Kil - One 11} Deluie Ullwsnmc Reg SH2 3:

Commjiiti Console" One tit Hand Held Remote Unit ■ Two j| '

l?l Lamp Module ■ One 111 Appliance Umi

Lamp Modules $14.50 Standard Command Console S36.00

ipUanca Modules $14.50 Uttosonic Command Console ceQ qc

■ •■ • . S14 SO ■■■ ' ■ ■ m.mP.i--.

BMBBm mhz

Portable Frequency Counter neg smM

Stereo Power Booster Z^'-'-'w.

Model POW-40 SO/IIS Histu^,

.40W stereo >24yS MSSQ

236 BYTE February 1980

855 Conklin St. Farmingdale, NY. 11735 ■ Master Charge ■ BankAmericard ■ VISA 4 ■ COD ■ Check ■ Money Order

N.Y. State residents add appropriate sales tax

free(800)645-9518

in N.Y. State call (516) 752-0050

Circle 201 on inquiry card.

10-DAY FREE TRIAL

Send for our FREE Catalog

$100 FREE ACCESSORIES WITH 16K or 32K PET

When you buy a 16K or 32K PET, apply $100 toward PET accessories, FREE. Just indicate on your order that you have reduced the cost of your accessories by $100.

Terminal Package with 8K PETs

See Special Below

PET ACCESSORIES

FftEt

V

8K-Keyboard N $795

16K-Keyboard B $905

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

SANYO MONITORS

9-inch reg $240

SALE! $169

Commodore Dual Floppy Disk Drive $1,295.00

Commodore Printer (friction feed) S849.00

Commodore Printer (tractor feed) S995.00

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 and Video Buffer S49.95

TNW Bi-Dir. RS-232 printerX-face .. $229

KIM 1 (A Single Board Computer

from Commodore) $179.00

PET OWNERS

Hazeltine 1400

Immediate Delivery — ?\ 2-Year Factory Warranty

'LIST SALE

$8C$ $649

Hazeltine 1410 Hazeltine 1500

- $835 $1069

Hazeltine 1510 —$1195 Hazeltine 1520 —$1499

SALE! $279

^>n

apple II

200 Ffi€€ fKC€SSORI€S

The new Apple II with Applesoft BASIC built-in! Eliminates the need for a $200 Firmware Card and includes new Autostart ROM for easy operation. This combined with the FREE accessories from NCE could save you up to $400 on a 48K Apple II system!

16K Apple II Plus — $1195 (take $100 in free accessories) 32K Apple II Plus — $1345 (take $150 in free accessories) 48K Apple II Plus — $1495 (take $200 in free accessories)

Apple II Accessories

General Business $625

PASCAL $495

Integer BASIC ROM Card $200

VISI-Calc $149

Centronics Printer Interface $225

Disk and Controller $595

Parallel Printer Card $160

Communications Card $225

Hi-Speed Serial Card $195

Firmware Card $200

IN STOCK NOW!

EVERY ITEM IN THIS ADVERTISEMENT IS IN STOCK AND READY TO SHIP, EXCEPT WHERE NOTED.

PAPER TIGER 440SPE

The Graphics Printer for Appie ii

Now you can print illustrations, block letters, charts, graphs, and more —all under software control- And with the expanded buffer, the Paper Tiger can hold the text from an entire 24-line-by-80-column CRT screen.

$1194.00

NCE/CompuMart «S

DEPT.KB20, 270 THIRD ST., CAMBRIDGE, MA 02142

To Order: 1 (800) 343"5504 In Mass: 1 (61 7) 491 "2700

REMOTE TERMINAL

for only $98

A self-contained module and program cassette enables your PET to function as a 300 baud terminal. Supports Upper/Lower case, Rubout, Escape & all control functions. Output is TTL.

WITH

PET

PURCHASE

Lear Siegler's ADM-3A

The ADM-3A is industry's favorite dumb terminal for some very smart reasons:

• 12 in. diagonal screen

• Full or half duplex operation at 11 selectable data rates

• 1920 easy-to-read characters in 24 rows of 80 letters

• Typewriter-style keyboard

• RS-232 C interface extension port

• Direct cursor addressing

Our Low Sale Price $795

COUPLER!

New 300 baud Originate/Answer Acoustic Coupler Looks good, works

^ ZENITH COLOR * VIDEO MONITOR

Zenith's first color video display designed specifically for computers.

This 13-inch monitor is Zenith's first color video display designed specifically for computers. Features include automatic color level, color processing and degaussing circuits.

Zenith Color Monitor $499.00

$189

from Heath Data Systems

The All-in-One Computer

Dual Z-80 Processors • Built-in 102K Floppy Disk • 16K to 48K RAM ■ 25 x 80 Character Display • Upper/Lower Case and Line Graphics • 80 Character Keyboard with Keypad ■ 8 User-definable Keys • Two BASIC'S and Auto-Scribe Word Processing available • Can support CP/M

Heath's third generation of computers is a compact, hi-style desktop unit which includes a complete terminal, a computer and a disk All-in-One! System includes Bootstrap in ROM, other programs available separately. HDOS operating system includes Heath's BASIC, an assembler and text editor along with important disk utilities. Microsoft language requires HDOS.

WHB9 with 16K RAM $2,295

WHB9 with 32K RAM $2,445

WHB9 with 48K RAM $2,595

WH17 Second Disk Drive $550

Dual-port Serial Interface $85

HDOS Operating System $100

Microsoft BASIC $100

Word Processing $395

<F

&

Just Released

Compumart's New Fall/Winter 1979 Catalog.

We've just published our catalog and its packed with new products and money saving specials. Our illustrated 32-page book features microcomputers and microcomputer systems from Apple, Commodore PET, Heath, and Exidy Sorcerer. Also covered are the Commodore's KIM and Rockwell's AIM. A broad selection of terminals, books, software and peripherals are presented in detail. The text is thorough and provides a wealth of technical information. To get your FREE copy write to our address below. Please include the dept. number to speed handling.

CENTRONICS 779-2 PRINTER

TRACTOR FEED

Parallel interface Continuous variable printing density 80-132 characters per line 5x7 dot matrix

SALE PRICE $1095

Form thickness control Horizontal and vertical form positioning Used with controller (Apple general business software) JUST ARRIVED. We've just received shipments of (he following Centronics printers. Call us for complete specs.

730-1 S995

730-3 SI 045

753-9 (9*9 Matrix) S2,795 704-9 {9*9 Matrix) $1,995

SINCE 1971

IMPORTANT ORDERING INFORMATION

All orders must include 4% shipping and handling. Mass. residents add 5% sales tax; Mich.

residents 4%, for sales tax.

Phones open from 8:30 a.m. to 5:30 p.m. EST Mon.-Frl. • P.O.'s accepted from D&B rated companies — shipment contingent upon receipt of signed purchase order • Sorry no C.O.D.s • All prices are subject to change without notice • Most items in stock for Immediate shipment — call for delivery quotation • In the Ann Arbor area? Our retail store Is open 11:00 a.m. to 7:00 p.m. Tues.-Frl., 10:00 a.m. to 5:00 pm. Saturdays (closed Sun. and Mon.)

VISA

Member: .*..•,.«. m , ..

Computer Dealers If not satisfied, return your purchase with-in 10 days for full

Association refund of purchase price!

Circle 202 on inquiry card.

BYTE February 1980 237

page

Precut Wire Wrap Wire

PRECUT WIRE SAVES TIME AND COSTS LESS THAN WIRE ON SPOOLS

Kynar precut wire. All lengths are overall, including 1" strip on each end. Colors and lengths cannot be mixed for quantity pricing. All sizes listed are in stock for immediate shipment. Other lengths available. Choose from colors: Red, Blue, Yellow, Orange, Black, White, Green and Violet. One inch tubes are available at 500. State second choice on colors when possible.

Length

100

500

1,000

Length

100

500

1,000

2.5 inches

1.04

2.98

5.16

6.5 inches

1.60

5.37

9.84

3

1.08

3.22

5.65

7

1.66

5.63

10.37

3.5

1.13

3.46

6.14

7.5

1.73

5.89

10.91

4

1.18

3.70

6.62

8

1.78

6.15

11.44

4.5

1.23

3.95

7.12

8.5

1.82

6.41

11.97

5

1.28

4.20

7.61

9

1.87

6.76

12.51

5.5

1.32

4.48

8.10

9.5

1.92

6.93

13.04

6

1.37

4.72

8.59

10

1.99

7.26

13.57

Kit #1 S7.95 Less than 2.7C/H. (#30)

Kit #2 Less than

$19.95 2C/ft. (#30)

KIT #3 $24.95 Less than 1.7C/M. (#30)

Kit #4 $44.95 Less than 1.6C/ft. (#30)

#30 Spools 1-4

5-9 10+

250 3" 100 4" 250 3" 100 5" 100 4" 100 6"

250 2'/?" 500 3" 500 3'/s" 500 4" 250 4'/2"

250 5" 100 S'A" 250 6" 100 61//' 100 7"

500 2Vi" 500 3" 500 3'/?" 500 4"

500 AW 500 5" 500 5V4" 500 6"

1000 2'/2" 1000 4W 1000 3" 1000 5" 1000 3V2" 1000 5" 1000 4" 1000 6"

50 ft. 1.75

100 ft. 3.00

250 ft. 4.75

500 ft. 8.50

1000 ft. 14.50

1.60 1.40 2.75 2.50 4.50 4.25 8.00 7.50 12.50 10.50

Wire Wrap Tool

BATTERY HOBBY TOOL* BW2630 Tool $19>85

• Autolndexing BT30 *30 Bit 2-95

• Anti-Overwrapping BT2628 #26 Bit 7.95

• Modified Wrap BC1 Batteries & Charger... 11.00

* Requires 2 "C" Nicad Batteries

Solderless Breadboarding

SK10 2/S25.00 _5i&6e

The SKIO's unique matrix configuration is embedded in a high temperature plastic molding. It gives you 64 pairs of 5 common spring contacts for principle circuit construction and a series of common buss strips (8) of 25 connections each. Dimensions: ,33"h x 2.2"w x 6.5"l

IC Sockets

RN HIGH RELIABILITY eliminates trouble. "Side-wipe" contacts make 100% greater surface contact with the wide, flat sides of your IC leads for positive electrical connections.

AVAILABLE AT SELECTED LOCAL DISTRIBUTORS

Tl Edge Card Connectors

44 pin ST (.156" centers) 100 pin ST (.125" centers) 100 pin WW (.125" centers)

All connectors gold plated.

WIRE WRAP

Size

Quant./Tube

Price Ea.

Price/Tube

SOCKETS

08 pin

WW 52

.31

$16.12

3-level Gold

14 pin

60

.32

$19.20

Closed Entry Design

16 pin

52

.34

$17.68

All prices include Gold

18 pin

23

.50

$11.50

2-level Sockets

20 pin 22 pin

21 19

.65 .70

S13.65 $13.30

Also Available

Sockets sold at these

24 pin 28 pin

10 10

.70 .95

$7.00 $9.50

prices by the tube only.

40 pin

7

1.20

$8.40

ORDERING INFORMATION

• Orders under S25, add $2 handling

• Blue Label or First Class, add $1 (up to 3 lbs.)

• CODs, VISA & MC orders will be charged shipping

• Most orders shipped next day

D32,© 135 E. Chestnut Street 5A, Monrovia, California 91016 Phone (213) 357-5005

Circle 203 on inquiry card.

CaMFornja DiqiTAl

Post Office Box 3097 B • Torrance, California 90503

software selectable character sizt characters per line. Full forms feed mechansim adjustable to 9.5' to accept either parallel or RS232 ***** $995.00 plu

CONNECTORS

imiuiuu.

3=

°m

m\

your choice

DB25P

male plug & hood

or

DB25S female

«3.25

Qty. fe. male hd. 10 3.05 1.95 1.15 25 2.95 1.79 1.05 100 2.65 1.S7 .95 500 2.25 1.60 .85 IK 1.97 1.37 .73

With Purchase of The INTEGRAL DATA 440

Paper Tteer

Your Choice, $200 Value

1) Graphics Option Package

2) Interface for APPLE II 3JTRS-80 Printer Interface

California Digital has resently researched the complete low cost printer market. It is our opinion that the IDS 440 Paper Tiger is, without doubt, the most versatile and offers the best value of any printer costing under $1,000.

This quality dot matrix printer incorporates such features as ■ to allow print densities upto 132 handling capabilities and tractor '. The Paper Tiger is engineered serial ASCII. 110/220V.50/60Hz. s shipping *****

Edge Connectors

GOLD 100 PIN

IMSAI/ALTAIR

Imsai solder 125*250 i2.95 3/4 7.50

Imsai w/w.l25centers (4.95 3/113.00

Altair soldertail.l40row $5.95 3/(15.00

SPECIALS

22/44 Kim eyelet. 156" SI.35 3/45.00

25/50 solder tab .156" 41.09 3/42.00

36/72 wide post w/w.156 41.95 3/45.00

Authorized Distributor lOPak 50*

O^.^i^-LJ 740-0 IB M soft format. $39.00 $3.50

OCOT.Cn ' !" Double sido soft 65.00 6,00

Dataproducts 741-0 Double density 53.00 4.90

743-0 Double/Double 70.00 6.60

740-32 8" Hard sector 39.00 3.50

744-(0)<10)(16) 5 l/4"miru 39.00 3.50 Library case for any above; Add $3.00

834 A Data Cassette 5.50

DC 100 Minicartridge 16.00

DC 300 Data Cartridge 20.00

920( ) Disk Cartridge 89.00

S-100 Mother Board

Quiet Boss

18 slot IMSAI

Minidisk Drive for TRS-80

your choice tff^QQ

J4>0 tacSs VlSta Interface Cable

TELETYPE MODEL 43

4320 KEYBOARD

TTL AAA $1050

RS232....AAK 1150

Friction ... AAE

103 Modem AAB 1575

1100 shipping

Ta?

rnrr PLASTIC LIBRARY CASE

rll PP with purchase of each box of ....

Verbatim mini-diskettes. J5 value.

DISKETTES

It's not iiITlti that Caiifon aires into ilit-' distribution ducts, but we have resently c a product that appeal's bo unique that we just had to add It to our product line. T his is the System x-10 manufactured by llV HSU turntable company. This space ace system will remotely control any light or appliance in your home or offices Command signals are transmitted from the command console over your existing wiring. From your bed or easy chair you can control up to IG different electrical devices inside and uulside your home. Use the System X-10 to control your stereo, television or any lifiltt fixture on the premises.

['he modular system is available in the following components;

Ultrasonic Master Control Console §34. 05

Battery Iterated Ultrasonic Controller 19.95

Appliance Module. Lamp Module or Wall Switch 13. 95

SPECIAL

APPLE II

I6K MEMOR'

COLOR • GRAPHICS* SOUND

$988

PLUS SHIPPING

Mfg.Sng. Retail....

9

■ Shugart Associates

SA800-R Floppy Disk Drive

Fhe most cost effective way to store data processing information, when random recall is a prime factor. The SA800 is fully compatible with the IBM 3740 format. Write protect circuitry, low maintenance & Shugari quality.

$44350

KEYBOARD

ASCII ENCODED

KEYTRONIC ASCII & ASCII complement. *Ten key data pad I ♦Cursor controls *Six user swi;ches|

* Alpha Lock

*Auto repeat

♦Single 5 volt.

*Glass reed.

NEW

MEMORY

TRS-80 Sj APPLE II

16k memory (8)4116's

Installation is simple. Anyone who has ever changed a spark plug should be able < to up-grade his microcomputer. How can California Digital offer these memory up-grade sets at 25% below our competition? Simple, we buy in volume, wholesale to dealers and sell the balance directly to owners of personal microsystems. These 16K dynamic memory circuits are factory prime and unconditionally guaranteed for one full year. NOW, before you change your mind, pick up the telephone and order your up-grade memory from California Digital. Add $3 for TRS80 jumpers.

STATIC 1-31

21L02 450nS. 1.19

21L02 250nS. 1.49 1

2114 1KX4 450 5.95 5

2114 1Kx4 300 8. 95 8

1044 4Kxl 450 5.95 5

4044 IKxl 250 9.95 9

4045 1Kx4 450 8. 95 8 4045 1Kx4 250 9.95 9 5257 low pow. 5. 95 5

SPECIAL CIRCUITS

Z80A 4 MHz. 24.95

8080A CPU 9. 95

8085 22.50

8086 Intel 16 bits 85. 00 T.MS 9900 16 bits 49.95

32-99 100-5C

999 , 90

1K+ .85

. 39

.50 .50

.50 . 50 . 50 . 50 . 50

1. 25 5. 25 8. 0D 5. 25 9.00 8. 00 9.00 5.00

4.80 4.60

AY5-1013A UART 4.95 Floppy Disc Controllers WD 1771 single D. 39. 95 WD 1781 Double D 65. 00 WD 1791 D/D3740 *

E PROMS 1-15 16-63 64+

1702A 2K 4. U5 4.50 4.00

2708 8K 9. 95 9.50 9.00

2716 5vl6K 39.95 35.00 *

2716 TI 24.38 20.00 *

2532 85.00 * *

>Jfi<{fP)i(

^•^nJi^

r

byapt=

A BRILLIANT

computer cyine

WHOSE TIME *P*Kji3 HAS COME. "

Miniature Switches

Iff

$.98 $.88 .81.73.66 SPDT Miniature Toggles

7101 C&K 0N-N0NE-0N

7107 jbt ONOFF(mnt.ON)

7108 CK OrHmomenl ON) 7103 CK ON OFF ON Rotary 3P-4Pos. Rotary 3P-6Pos. Push B IN 0.) S.39u.i. 4 S1

your choice

50 1001k

DIP Switch

sl?9

25 100 IB

PORTABLE DATA ENTRY SYSTEM

terminals nwe originally designed for chain store inventory conniry systems. The operator enters the inventory control number, hand and the unit price. After all pertinent data has been entered into le recorder, the main warehouse is telephoned, the handset is placed in the tcoustic jupler and all the recorded information Is transmitted hack to the master computer, ith a Iiiilf invagination and one of these portable entry systems, you i exchange programs and computer information with associates aero; units «ere removed from service in working condition. Original t

table Cassette Drive Unit -Five Could "IJ" NtCads >UB:

lovable Entrv Keyboard "Acoustical Coupler .Shoulder st

ill, LED Display 'Batten- Charger •Full Docun

trol and c

All

should be able is the country.

ost 52.500. tS Cable

DISCOUNT ' |

Wire UU rap Center

IC SOCKETS

wire wrap ea. 25 50

low profile ea. 25 50

17< 16 15

37<36 35

18 17 16

38 37 36

19 18 17

99 93 85

36 35 34

169 155 139

63 60 58

5.39.95 I

soft.

s.98

500 1,000 11,000 S9. S15. J105.

VISA

(213)679-9001

Circle 204 on inquiry card.

All merchandise sold by California Digital is premium grade. Sorry, no COD's. Orders are shipped the same day received. California residents add 6%. Foreign orders add 10%. Orders over $25, when accompanied by payment, are shipped at our expense. Otherwise, please add $2.

BYTE February 1980 239

FLOPPY SYSTEMS

8" Siemens FDD120-8D

AM Siemens options included in this drive may be configured hard or soft and single or double density. We find this to be an extremely reliable drive. $430.00 Fully Shugart compatible. SV" BASF Magical Miniature Mini drive only 2/3 the size of others is reliable and durable and quickly gaining in popularity with our customers. Single or dual density fast access times $259.00

Tarbell Controller may be reconfigured to control 5V drives and includes short cable for one drive. KIT $179.00, ASM $265, but only$219 with purch. of 2 drives.

Cable Kits For 8" Drives with 10' 50 cond. cable and conn i> ectors. Also power cable and HP connectors. Flat cable assem

if you wish. For one drive 27.50, two 33.95, three 38.95

Cable Kits for 5V«" Drives as above, but 34 cond. For one drive 24.95, two 29.95.

SOFTWARE: SUPERDOS I (Z-80) Single User, UNIX-Like File System, AND Totally Upward Compatable From "XX/X" (What did you say, Digital Research??)

PS: SUPERDOS -I runs on the TRS-80, and can transform it from a toy computer to a real business machine !!!

10MBy DRIVE $3300

S- 100

DMA

CONTROL

POWER

UNIT $395.00

For the first time in something like 10 years, a new STANDARD in removable media has evolved. Selected by Datapoint, and others who have not yet announced, this drive is beautifully simple and easy, if not trivial to maintain. 920kBy/sec. transfer rate, 3600 RPM 39 lbs and only 125 Watts.

32K-$490.00 16K

"Power One" Model CP206 Power Supply adequate for at least two drives. 2.8A/24V 2.5A/5V, 0.5A/-5V beautiful quality. $99.00

CABINETS for FDD120and 801 B drives, or CP206 supply. Matte finish in mar resistant black epoxy paint and stacking design 29.95

DISKETTES

(3M, MRX, BASF, Georgia Magnetics, & Victor Borge) 8" $39.95/10 5%" $29.95/10 $290.00

NEW!! - CHRISLIN 64K Dynamic RAM $750.00 (Showing Amazing Similarity to TarbeM's unit) (16K Shown in photo)

.,_,,....... .

|pg||ffpffy

32K-$549.00 16K-$349.00

"BACK TO SCHOOL" KEYBOARD SPECIAL

CHERRY "PRO" Keyboard $119.00 Streamlined Custom Enclosure $34.95 BOTH ONLY $124.95 !!!!!!!!

Elect rolabs

POB 6721, Stanford, CA 94305

415-321-5601 800-227-8266

Telex: 345567 (Electrolab Pla) Visa MC Am. Exp.

Daisy Wheel Printers |H Qume Sprint 3\45

PRINTER (factory warr.) $1199.00 POWER SUPPLY (Boschert) $349.00 (shown mounted on rear of printer)

COMBINATION SPECIAL $1699.00

DATA DISPLAY MONITORS

Used 12" Sylvania monitors. Composite Video, 15 MHz, 120VAC. Rebuilt with NEW P39 anti-glare tube $119.00 New P4, 109.00, used P4 79.00. U-fix model, 10/$300.00

New!

ESAT 200B

BILINGUAL 80x24

COMMUNICATING

TERMINAL

Scrolling, full cursor, bell, 8x8 matrix, 110- 19,200 baud, Dual Font Applications. Arabic & Hebrew, Multilingual Data Entry Forms Drawing, Music, & Switchyards. $349.00

»gf«f mim m wit m i\

£ ^isv <,*',iw:t*

OEM STYLE" as above, will fit any case. (Both versions serviced by qualified tech). Identical to above but subtract $12.00

Doppler Motion Sensor Intrusion Detector

Extremely effective microwave motion detector for detecting unwanted visitors. Ignores mice and other non-larcenous creatures. Operates on 12VDC or from small transformer supplied. Output is relay closure for alarm control interface, or to switch on lights annunciators. Will operate THROUGH door of closet or thin wall. Best application seems to be to turn on outside lights to help invited guests, and to intimidate unwanted ones. $159.00 Water Repellent Cover S24.95

SOCKET SPECIAL

"Won't Let Go"

Low Profile Solder Tail 1 CENT/Pin!! (0.75/1000's)

8 14 16 18 20 22 24 28 40

240 BYTE February 19B0

CP/M* Source Code --FREE! when you purchase "OS-1" Electrolabs' new operating system for the Z-80 designed to have exactly the appearance of UNIX**, including virtual I/O, "set TTY", a tree and a shell, filters and pipes PLUS total compatability with CP/M software!

^^% ^^k ^fl © (Because OS-1 is truly a comprehensive

I I ^^ "OS", and not merely a file handling

I B ^ "i I ccatiidtc "DOS",we have changed the name

^J \J I rtrtlUHtb from "Superdos" to "OS-1")

VIRTUAL I/O - copy with a single command between floppy and hard

disk, or from TTY to printer to tape to disk... etc., etc.

No messy I/O routines to write, & no awkward transfers. SECURITY - 9 modes of file protection, user and login protection. MULTI-USER - up to 256 passwords, (non-simultaneous users) 16MBy FILE SIZE - but no limit to no. of directories per device, thus

allowing EASY implementation of gigantic storage devices. "SET TTY" - for printer or crt: tabs, page width, buffer, cursor, UC/LC,

fonts, formfeed, arbitrary control characters etc., etc. "LOGIN" - automatically executes user selected programs and "set TTY". OCCUPIES 12KBy - only 50% larger than CP/M, but 500% more features. CP/M & CDOS COMPATABLE - your library is guaranteed to run!

* (Naturally, we are not giving away the version of CP/M written by Digital Research, Please pardon our pun, but they might object. What we ARE giving you is a greatly enhanced version of CP/M which resides on OS-1, and allows the user of OS-1 to run any and all of his programs, packages or system utilities which are already running on CP/M. We give you the source code at no charge so that you may modify any part of the CP/M to suit your own system requirements. At no charge, you also receive the enhancement allowing 4MBy files instead of 256K.)

OS-1 (with debugger, linker and screen oriented editor $199.00

Update service, per year 29.00

Symbolic Debugger 150.00

MACRQ-Assembler (Creates relocatable code) 150.00

"C" Compiler 660.00

FORTRAN Compiler 100.00

BASIC Compiler (very fast) 350.00

PAPER TIGER

IDS MODEL 440

— 8 Software Selectable Character Sizes

— Parallel & Serial Interface

— 98 ASCII Character set, upper & Lower case

— Forms length control

— Tractor Feed $995.00 Graphics option with 2K CRT

screen buffer add $199.00

DYNAMIC DEVICES MODEM

— Acoustically coupled modem

assembly set />ri.

- Asynchrous 0-300 Baud jf|

— Switchable originate or answer

modes ^~ ,.

— Operates full or half duplex ;HC"1B

■i^I_"~-—-^.. Wt

mode ^^|W

— 15 minute assembly $149.95

NEW YEAR'S IC (While Supply Lasts)

MEMORY &EPR0M

2114- $ 3.00

2114-2 6.99

Pd411 2.50

2107 (pull outs) 2.00

SPECTACULAR

7001 (pull outs) 2.00

4116 (set of 8,

16K)

69.00

5204

4.95

2708

8.95

2516

35.00

2716

35.00

ELECTROLABS POB6721 Stanford, CA 94305 415-321-5601 800-227-8266 Telex: 345567 (Electrolab Pla)

TMS2716

19.00

2732

95.00

CPU

1802CD

$19.95

6502

6.25

Z-80

9.95

Z-80A

12.95

8080A

8.99

8085

2Z00

8741

79.00

FLOPPY CONTROLLERS

1771 $26.95

1791 37.95

Pd372 39.00

MISCELLANEOUS (CALLUS!!)

Graphics

High Resolution ' 480x512

for B&W and Color Imaging and Graphics

ght pen, A-D, D-A, TV synchro (needs no time base correction or adjustment with anything between random interface & NTSC commercial standard). T.V. single frame grabber ("snapshot"). Up to 1 Byte of attributions per pixel.

LSI-100&S-100 applied to:

Graphic Presentation — such as computer generated animation Si other graphic displays up to 256 colors & up to 256 b&w gray scales. Image Analysis - using built-in FRAME GRABBER, for medical image enhancement, contour analysis, & pattern recognition. Commercial TV

Tilting & Advertising — using synchronization capability. Interactive

graphics — using light pen accessory.

BASIC CONFIGURATION

LSI-11$1995. S-100$1265. For TRS-8D/Exidy Add $595.00 Includes: Data Board - 32K (480 x 512 x 1 pixel) D-A 16 level video generator. Video Synchronization Circuitry. Address Control & Timing Board.

FEATURES - High speed. DMA or 2KBy window memory mapped interface. Full NTSC commercial color capability. Low power consumption. Excellent Software

Options - Accessories - Software

Options include: light pen, auxilliary outputs, text mode, memory and much more. Accessories include: b&w and color cameras and monitors. Software: "Plot" 2D or 3D, "Tilting", "Contour", "Image Enhancement", "Vector Curve Generation".

Call for price and details

•CPM and "UNIX

trademarks of Digital Research and Western Electric respectively

Circle 206 on inquiry card.

BYTE February 1980 241

MATCHMAKER TECHNOLOGY

TURNKEY DISK SUBSYSTEMS

DISK

IS

IN!!!

For those who wish to avoid the aggravation, fussing, irritation, annoyance etc., of assembling your own subsystem, plug in and GO!!!

^SORCERER sTRS-80 tsAPPLE

1 ^HPIB sPET

APPLE

SORCERER

FEATURES:

— 2 8" Floppy DISK DRIVES (Single Sided)

— Color Coordinated Cabinet with Power Supply

— Expanded version of APPLE-DOS

— Single Density Disk Controller

— Full Cabling, Connectors + Documentation

— Assembled and Tested

-Plug In and GO!!! $1695.00

OPTIONS:

— 2 8" Double Sided Drives (In place of Single Sided)

$2395.00

— 16K Internal Memory Expansion Kit 69.00

PET

Prices and specifications same as for APPLE except PET Operates via PET-DOS

TRS-80

Prices and specifications same as for SORCERER with following exceptions:

— Expansion Interface necessary

— Space for up to 48K plug-in dynamic memory on Controller Card

— Software package as above $ 995.00

FEATURES:

— 2 8" Single Sided Floppy Disk Drives

— Single and/or Double Density

— Color Coordinated Cabinet with Power Supply

— Full RS-232 Interface

— OS-1 Disk Operating System (Fully CP/M

Compatible) CP/M is a registered trademark of Digital Research

— Full Cabling, Connectors + Documentation

— Assembled and Tested

— One S-100 Slot available for Memory Expansion -Plug In and GO!!! $2195.00

OPTIONS:

- 2 8" Double Sided Drives (In place of Single Sided)

$2845.00

- 32K Dynamic RAM Memory Board, Assembled and Tested $ 299.00

- 16K Dynamic RAM Internal Memory Expansion Kit

$ 69.00

- Deluxe Business Software package includes: C BASIC

WORD PROCESSING SOFTWARE INTERACTIVE "Big 4":

General Ledger, Accts. Payable, Accts. Rec.

and Payroll $ 695.00

- 10 MBY Removeable Hard Disk - Call for Details

ANOTHER Fine Product brought to you exclusively by the folks at:

In California: 415-321-5601 Outside Cal: 800-227-8266

Electrolabs

Worldwide:

TLX: 345567 Electrolabs PLA

FOB 6721, Stanford, Ca. 94305

242 BYTE February 1980

MICROLEASE!

A unique nationwide leasing program designed to facilitate the purchase and sale of computers and peripherals.

Whether you are buying or selling, MICROLEASE is your best leasing choice.

Excellent Rates. Fast Service by Computer Professionals.

EVERGREEN

22 Concord Avenue

Cambridge, MA 02138

(617)868-3425

16 K RAMS & RAM CONTROLLERS

16 K X 1 DYNAMIC RAMS mimii6P3

• 200 NSEC ACCESS/375 NSEC CYCLE TIMES

• 16PIN/TTL COMPATIBLE

• ALL CHIPS BURIED IN AND FULLY TESTED

• PRICE WITH DATA SHEET

S66.00 IN OTY OF 8/THAT'S 58.50 EACH

6800/6502 64K BYTE RAM & CONTROLLER SET MAKE 64K BYTE MEMORY FOR YOUR 6800 OR 6502 THIS SET INCLUDES

• 32 M5K 4116-3. 16K X |, 200 NSEC RAMS

• 1 MC3480 MEMORY CONTROLLER

• 1 MC3242A MEMORY ADDRESS MULTIPLEXER AND COUNTER

• DATA & APPLICATION SHEETS PARTS TESTED AND GUARANTEED.

S295.00 PER SET

DYNAMIC MEMORY CONTROLLER MC3480L

• GENERATES RAS/CAS & REFRESH TIMING FOR 16K TO 64K BYTE MEMORIES

. PRICE WITH OATE SHEET S13.95 EACH

MEMORY ADDRESS MUX/COUNTER mc3W?ap

• MUX ADDRESS S REFRESH COUNTER FOR 16K TO G4K BYTE MEMORIES

• PRICE WITH DATA SHEET S12.50 EACH

OUANTUY DISCOUNTS AVAILABLE All ORDERS POSTPAID US FUNDS 0% INTERNflTID'JJ".!

ORDERS CHEEK Dfl M0NEV ORDER VISA18A.MC AIS0 AC CEP1EC SEWJAl'CT NO EXPIRATION DATE &INTEB8ANK NO WITH SIGNED ORDER CALIF RESIDENTS PLEASE ADO (iS SAIES TAX PHCJE OflOtHS 1/IJ1 633 4460

MEASUREMENT SYSTEMS & CONTROLS, inc

MEW0R1 DEVICES DIVISION 66/ NORTH MAIN ST.. ORANGE CA 92BfiB

Circle 208 on inquiry card.

Circle 209 on inquiry card.

Circle 210 on inquiry card.

APPLE DOS COMPATIBLE

• DOUBLES APPLE ] I" STORAGE

• SHUGART 800/801 COMPATIBLE

• STANDARD IBM" 3740 FORMAT

• CP/fvTUCSD PASCAL"" CAPABILITY

Available at your local APPLE Dealer: $400.

SORRENTO VALLEY ASSOCIATES

Circle 211 on inquiry card.

TRS-80, PET, APPLE,

SORCERER

Hardware/Software Systems

Available Now:

MHAM INTERFACE - including the most sophisticated RTTY systems money can buy. UBaudot and ASCII printer interfaces.

MEIectra Sketch- .ANIMATION GRAPHICS Compiler.

Write or tall far free catalog

/VMCROTRONICS, inc.

1125 N. Golden State Blvd. Suite G (A) Turlock, CA. 95380 (209) 634-8888/667-2888

We are experiencing telephone difficulties, please keep trying.

FLOPPY DISK REPAIR

I|t?i::?;#''";":,|,T't,'*vi;:"*Tii!:?i::::;<ii1':'

I':'.- VI " ■■'■■ '"I '■' " <<'

• PerSci, Shugcirt Apple

• Quick Turnaround

• Reasonable prices

yi.^tZrrf'j^r'i^iivi;::::::::::^!;::!::;:::::^*,;,

Computer Service Center

1023 N. LaBrea

Hollywood, CA 90038

213-851-2226

Circle 212 on inquiry card.

HOW CAN I GROW B TREES?

ORDER MICRO B +™

• Get fast insertion, retrieval and deletion of index entries.

• Never need to reorganize your index; no matter how often it is updated.

MICRO B+ SOURCE CODE $195 MICRO B + DEMO DISK $25

SHIPPING $2 USA. $5 FOREIGN

Available in 8" format lor CBASIC-II

and MICROSOFT Basic Version 5.

314-445-3304 Check/ VISA/ Mastercharge

SPRINT 68 MICROCOMPUTER

CONTROL COMPUTER DEVELOPMENT 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, parallel I/O, 488 GPIB

WIN! hi:

Corp

1801 South Street Lafayette, IN 47904 Phone: (317) 742-8428

Circle 213 on inquiry card.

CASSETTE DUPLICATION

TRS-80 (I & II), PET, APPLE, KIM, ATARI

Quality software duplication is more than copying cassettes. Microsette duplication uses a proprietary high speed duplicator designed specifically for computer program duplication. The finished products are of consistent quality, guaranteed to load. Minimum order is 100 with discounts for higher quantities. Call (415) 968-1604 for details.

1

»

l».

Mffl»t|

S • ■■ • 4!

1 = • mt m »

MICF

475

Mt.Vi

OSETTE CO. Ellis Street ew, CA 94043

Circle 214 on inquiry card.

Circle 215 on inquiry card.

Circle 216 on inquiry card.

C04000 CD4001 CD40G2 CD4Q06 CD4007 CMOQS CD4010 CD4011 CD40I2 CD4013 CD4014 CO401S CD4016 CD4017 CD40I8 CD4019 CD4020 CD4021 CD4022 CD4023 CD4024 CD4025 CD4026 CD4027

74COO 74C02 74C04 74C08 74C1D 74C14 74C20 74C30 74C42 74C48 74C73 74C74

78MG

LM106H

LM300H

LM301CN/H

LM3Q2H

LM304H

LU305H

LM307CN/H

LM308CN/H

LM309H

LM309K

LM310CN

LM311N/H

LM312H

LM317K

LM318CN/H

LM319N

LM320K-5

LM320K-5.2

LM320K-12

LM320K-15

LM320K-18

LM320K-24

LM320T-5

LM320T-5.2

LM320T-B

LM320T-12

IM320T-15

LM320T-1B

LM320T-24

LM323K-5

LM324N

LM339N

LM340K-5

LM340K-5

LM340K-8

LM340K-12

LM340K-15

74LS00 74LS01 74LS02 74LS03 74LS04 74LS05 74LSOB 74LS09 74LS10 74LS11 74LS13 74LS14 74LS15 74LS20 74LS21 74LS22 74LS26 74LS27 74LS28 74LS30 74LS32 74LS37 74LS40 74LS42

7400 TTL

SN7470N SN7472N SN7473N 5N7474N SN747SN SN7476N SN7479N SN74S0N SN74B2N SN7483N SN74B5N SN7486N SN74B9N SN7490N SN7491N SN7492N SN7493N SN7494N SN7495N SN7496N SN7497N SN7410ON SN74107N SN74109N SN74116N SN74121N SN74122N SN74123N SN7412SN SN74126N SN74132N SN74136N SN74141N SN74142N SN74143N SN74144N SN74145N 5N74147N SN74148N SN74150N SN74151N SN74152N SN74153N SN74154N SN74155N SN74156N SN74157N

2.95 2.95

? 9S

C/MOS

CTJ4028 CD4029 CO4O30 CO4035 CD4040 CD4041 CD4042 CD4043 CD4044 CD4046 CD4047 CD4048 CD4049 CD4050 CD4051 CO40S3 CD4056 CD4059 CD4Q60 CD40E6 CD4068 CO40G9

74C00

74C85 74C90 74C93 74C95 74C107 74C1S1 74tl54 74C157 74C160 74C161

LINEAR

LM340K-18 1.35

LM340K-24 1.35

LM340T-5 1.25

LM340T-6 1.25

LM340T-8 1.25

LM340T-12 1.25

LM340T-15 1,25

LM340T-18 1.25

LH340T-24 1.25 LM358N

LM370N

LM373N

LM377N

LM380N

LM380CN

LM3B1N

LM3B2N

NE501N

NE510A

NE529A

NEsaiHAf

NE536T

NE540L

NE544N

NE55DN

NE555V

NE556N

NE560B

NE562B

NE565N/H

NE566CN

NE567V/H

NE570N

LM703CN/H

LM709N/H

1.95 3.25

74LS00TTL

74LS47 74LS51 74LS54 74LS55 74LS73 74LS74 741S75 74LS76 74LS78 74LS83 74LS85 74LS86 74LS90 74LS92 74LS93 74LS9S 74LS96 74LS107 74LS109 74LS112 74LS123 74LS125 74LS132 74LS136

^W

SN74160N SN74161N SN74162N SN74163N SN74164N SN74165N SN74166N SN74167N SN74170N SN74172N SN74173N SN74I74N SN74175N SN74176N SN74177N SN74179N SN741B0N SN741B1N SN741B2N SN74I84N 5N74185N SN74186N SN741B8N SN74190N SN74191N SN74192N SN74193N SN74194N SN74195N SN74196N SN74197N SN74198N SN74199N SN74S200 SN74251N SN74279N SN742B3N SN74284N SN74285N SN74365N SN74366N SN74367N SN74368N SN74390N SN74393N

CD407O

CD4071

CD4072

CD4Q76

CD4081

CO40B2

CD4093

CO4098

MCI 4409

MCI4410

MC14411

MC14419

MC14433

MCI 4506

MC14507

MC14562

MC145B3

CD4508

C045I0

CD4511

CD4515

CD4518

CD4520

CD4566

74C163 74C164 74C173 74C192 74C193 74C195 74C922 74C923 74C925 74C926 80C95 80C97

1 50

LM710N .79

LM711N .39

LM723N/H .55

LM733N 1.00

LM739N 1.19

LM741CWH .35

LM74M4N .39

LM747N/H .79

LM748N/H .39

LM1310N 1.95

LM1458CN/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

LM3Q65N 1.49 LM3900N(3401).59

LM3905N 1.48

LM3909N 1.25

MC5558V .59

LM75450N

75451CN

75452CN

75453CN

75454CN

75491CN

75492CN

75493N

75494CN

RC4136

RC4151

RC4194

RC4195

■155

74LS138 74LS139 74LS151 74LSI55 74LS157 74LS160 74LS161 74LS162 74LS163 74LS164 74LS175 74LS1B1 74LS190 74LS191 74LSI92 74LS193 74LS194 74LS195 74LS253 74LS257 74LS258 74LS260 74LS279 74LS367 74LS3BB 74LS670

aCromemco Incorporal ed

mom

Cromamco's 8K BYTESAVER® card provides a built-in programmer for the popular 2708 PROM and has the capacity for a full i! K bytes of PROM memory storage. Tho BYTESAVER® II also offers a number of new features including convenient switch selection of board address and Cromemco's powerful memory bank selection. The BYTESAVER® II is assembled and tasted (Model 8KBS-W) for $245.

8K Bytcsaverll

Memory Capacity: 8K bytes

Memory Type: 2708 PROM or equivalent

Memory Access Time: 450 nanoseconds

Wait States at 2MHz: none required

Wait States at 4MHz: one per machine cycle

Bus: S-1O0

Power Requirements: +8V @ 0.8A +18V@0.4A -1 8V 9 0.2A

Operating Environment: 0-55°C.

Assembled

8KBS-W... $245.00

DISCRETE LEDS

ZOO" ma.

XC556R

red

XC556G

green

XC556Y

yellow

XC556C

clear

.200- die.

XC22R

red

XC22G

green

XC22Y

yellow

170" die.

MV10B

red

085 die.

MV50

red

INFRA-RED

1/4-K1/4M/16

5/S1

5/11

125- die.

4/S1

XC209R

red

5/{1

4/$f

XC209G

green

4/J1

4/$1

XC209Y

yellow

4/S1

5/S1 Ml

4/11

IBS" die.

XC526R

red

MSI

XC526G

green

4/S1

XC526V

yellow

«Si

4/S1

XC52GC

clear

4/S1

190 dla.

6/J1 LED

XC111R

red

SSI

XC111G

green

m

XC111V

yellow

4/S1

XC111C

clear

4/S1

TIMEXT1001

LIQUID CRYSTAL DISPLAY CLASS II

FIELD EFFECT

4 DIGIT- 5" CHARACTERS THREE ENUNCIATORS 2.00" X 1.20" PACKAGE INCLUDES CONNECTOH

TIOOI-Transmiwive $7.95

TirJ01A<Reflectiue B.25

DISPLAY LEDS

TYPE MAN 1 MAN 2 MAN 3 MAN 4 MAN7G MAN 7Y MAN 72 MAW 74 MAN 82 MAN 84 MAN 3620 MAN 3630 MAN 3B40 MAN 4610 MAN 4640 MAN 4710 MAN 4730 MAN 4740 MAN 4810 MAN 4840 MAN 6610 MAN 6630 MAN 6640 MAN 6650 MAN 6660 MAN 66BO MAN 6710

POLARITY I

Common An ode-red 5 x 7 Dal Matrix-red Common Cathode-red Common Cathode-red Common Anode'green Common Anode-yellow Common Anode-red Common Cathode-red Common Anode-yellow Common Cathode-ye I low Common Anode-oranoe Common Anodo-oranrjo ± 1 Common Cathode-orange Common Anode-oranne Common Cathode-orange Common Anodo-rert .

Common Anode-red & 1 Common Cathode-red Common A node-yellow Common Calhode-yellaw Common Anode-orange-D-D Common Anode-orange ± 1 Common Caihode-orango-O.O. . Common Cathode-orange * 1 . Common Anode-orange Common Cathode-orange Common Anode-ied-D.D

TYPE

MAN 6730

MAN 6740

MAN 6750

MAN 6760

MAN 6780

DL70t

DL704

DL707

DL72B

OL741

DL746

DL747

OL749

0L750

DL33B

FND70

FN035B

FND359

FNDS03

FN0507

5082-7730

HDSP-3400

HDSP-3403

5082-7300

5083-7302

50B2-7304

5082-7340

POLARITY

Common Anode-red * 1 Common Cathode-refl-D.D. Common Cathode-red s 1 Common Anode-red Common Cathode-red Common Anode-ted = 1 Common Cathodo-red Common Anode-red Common Ca!hode-red Common Anode-red Common Anode'red = 1 Common Anode-red Common Cathode-red t 1 Common Cathode-red Common Cathode-red Common Cathode Common Cathode ± 1 Common Cathode Common Cathode)FND500) Common Anode (FND510) Common Anode-red Common Anode-red Common Cathode red 4x7 sgl. Digit-RHDP 4 x 7 Sgl. Digit-LHDP Overrange character (±1) 4x7 Sgl. Digit-Hexadecimal

19.95 15.00 22.50

RCA LINEAR

CA3013T CA2023T CA3035T CA3039T CA3046N CA3059N CA3060N CA30B0T CA3081N

2.15 CA3082N

2.56 CA30B3N

2.48 CA3086N

1.35 CA30B9N

1.30 CA3130T

3.25 CA3140T

3.25 CA3160T

.85 CA3401N

2.00 CA3600N

CALCULATOR CHIPS/DRIVERS

MMS725 S2.95

MM5738 2.95

DM8864 2.00

DM8S65 100 DMB887 .75

DM8889 .75

9374 7 seg. C.A. LEO d

CLOCK CHIPS

MOTOROL/

MM5309

S4.95

MC1408L7

M SS

MM5311

4.95

MC1408LB

S75

MM5312

4.95

MCI439L

9M

MM5314

4.95

MC3022P

?95

MM5316

6.95

MC3061P

3.50

MMS318

9.95

MC4016(74416)

1 Mt

MM5369

2.95

MC4024P

3.95

MM5387/1998A

4.95

MC4040P

H.95

CT700I

695

MC4044P

4.50

B pin LP 14 pin LP 16 pin LP 18 pin LP 20 pin LP

24 pin ST 8 pin SG 14 pin SG 16 pin SG 18 pin SG

Spin WW 10 pin WW 14 pin WW 16 pin WW 18 pin WW 20 Din WW

IC SOLDERTAIL — LOW PROFILE (TIN) SOCKETS 49 50-100 1-24

22 pin LP S .37

24 pin LP .38

28 pin LP .45

.27 36 pin LP 60

30 SOLDERTAIL STANDARD (TIN) 40 P'n LF w

2B pin ST S .99 36 pin ST 1.39 40 pin ST 1.59

SOLDERTAIL STANDARD (GOLD)

24 pin SG S .70 ?BplnSG '10 36 pin SG 1-6S

25-49 50-100

WIRE WRAP SOCKETS (GOLD)LEVEL #3

22 pin WW S .95 24 pin WW 1.05 2BplnWW 1.40 36 pin WW 1.59 40 pin WW 1.75

10 OHM 12 OHM

27 OHM 33 OHM

6B OHM 82 OHM

1B0 OHM 220 OHM 770 OHM 330 OHM 390 OHM

470 OHM 560 OHM 680 OHM 8?0 OHM IK

15 OHM 39 OHM 100 OHM

18 OHM J 7 OHM 120 OHM

50 OHM

50 PCS 50 PCS

1/4 WATT RESISTOR ASSORTMENTS - 5%

$1.75 1.75 1.75 1.75 1.75 1.75

1.75

ASST. 8R Includes Resistor Assortments 1-7 (350 PCS.) $9.95 ea.

1.?K

3.3K

1,-SK

3.9K

J 70K 1.2M 3.3M

2.2K 5.SK

2.7K 6.8K

S10.00 Min. Order - U.S. Funds Only Spec Sheets — 254

Calif. Residents Add 6% Sales Tax 1980 Catalog Available -Send 41 d stamp

Postage — Add 5% plus$1 Insurance (if desired)

PHONE

ORDERS

WELCOME

(415) 592-8097

ameco

ELECTRONICS

MAIL ORDER ELECTRONICS - WORLDWIDE

1355SHOREWAY ROAD, BELMONT, CA 94002

ADVERTISED PRICES GOOD THRU FEBRUARY

TELEPHONE/KEYBOARD CHIPS

AY-5-9100 Push Button Telephone Dialler

AY-5-9200 Repertory Dialler

AY-5-95O0 CMOS Clock Generator

AY-5-2376 Keyboard Encoder (68 keys)

HD0165 Keyboard Encoder (16 keys)

74C922 Keyboard Encoder (16 keys)

74C923 Keyboard Encoder (20 keys)

SM.«\

14.95 4.95

14.95 7.95 7.95 6.25

ICM CHIPS

ICM7045

CMOS Precision Timer

24.95

ICM7205

CMOS LED Stopwatchmmer

19.95

ICM7207

Oscillator Controller

7.50

ICM7208

Seven Decade Coonler

19.95

ICM7209

Clock Generator

6.95

NMOS READ ONLY MEMORIES

MCM6571 128 X9X 7 ASCII Shifted with Greek 13.50

MCM6574 128 X 9 X 7 Math Svmbol & Pictures 13.50

MCM6575 128 X 9 X 7 Aloha1 Control Char Gen 13.50

TL074CN

TL494CN

TL496CP

I1C90

951190

4N33

MK50240

OS0026CH

TIL308

MM5320

MM5330

LD110/111

MC14433P

MISCELLANEOUS

Quad Low Noise bi-fet Op Amp Switching Iteijulator Single Switching Regulator Divide 10/11 PrescaTer Hi-Speed Divide 10/11 Prescaler

2.49 4.49 1.75 19.95 11.95 3.95 17.50 3.75 .27" red num. display w/integ. logic chip 10.95 TV Camera Sync. Generator 14.95

4'/z Digit DPM Logic Block (Special! 3.95

3Vi Digit A/D Converter Set 25.00/set

3v* Digit A/D Converter 13 95

Photo-Darlington Opto-lsolator Top Octave Freq. Generator 5Mhz 2-phase MOS clock driver

LITRONIX ISO-LIT 1

Photo Transistor Opto-lsolator ISame as MCT 2 or 4N25)

49i< each

SN 76477

SOUND GENERATOR Generates Complex Sounds Low Power - Programmable

$3.95 each

TV GAME CHIP AND CRYSTAL

AY-3-8500-1 and 2.01 MHZ Crystal (Chip & Crystal - n_ . .

includes score display. 6 games and select angles etc. 7.95 /SBt

$8.40 4.40 4.40 1.55 1.50 .39

XR205 XR210 XR215 XR320 XR-L555 XR555 XR556 XR567CP .99 XR567CT 1.25 XR1310P 1.95 XR1468CN 3.85 XRI488 1.95 XR1489 1.95

EXAR

JE2206KB 19.95

XR1800 3.20

XR2206 4.40

XR2207 3.85

XRZ208 5.20

XR2209 1.75

XR2211 5.25

XR2212 4.35

XR2240 3.45

XR2242CP 1.50 XR2264 4.25

XR2556 XR2567 XR3403 XR4136 XR4151 XR4194 XR4202 XR4212 XR4558 XR4739 XR4741

3.20 2.99 1.25 1.25 395 4 95 3.60 2.05

TYPE

1N746

1N751

1N752

1N753

1N754

1N757

1N759

1N959

1N965

1N5232

1N5234

1N5235

1N5236

1N5242

1N5245

1N456

1N458

1N4B5A

1N4001

DIODES

VOLTS W

3.3 400m

5.1 400m

5.6 400m

2,0 400m

12.0 400m

8.2 400m

15 400m

5.6 500m

6.2 500m

6.8 500m

7,5 500m

12 500m

15 500m

4/1,00 4/1,00 4/1.00 4/1.00 4/1.00 4/1.00 4/1.00 4/1.00

TYPE 1N4002 1N4003 1N4004 1fJ4005 1N4006 1N4007 1N3600 1N4148 1N4154 1N4733 1N4734 1N473S 1N4736 1N4738 IN4742 1N4744 1N1183 1N11B4 1N1185 IN1166 1M11B8

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 200m

PRICE 12/1.00 12/1.00 12/1.00 10/1.00 10/1.C

75

torn

35 10m

12

1w

50 PIV 35 AMP 100 PIV 35 AMP 150 PIV 35 AMP 200 PIV 35 AMP 400 PIV 35 AMP

SCR AND FW BRIDGE RECTIFIERS

C36D 15A rjj 400V

C36M 3SA(ii 600V

2N2328 1.6AI6 300V

MOA 980-1 I2Af« 50V

MDA 980-3 12A<« 200V

C106S1

MPSA05

MPSA06

TIS97

TIS9B

40409

40410

40673

2N918

2N2219A

2N2221A

2N2222A

PN2222 Plastic

2N2369A

MPS2369

2N2484

2N2906

2N2907

PN2907 Plastic

2N2925

MJE2955

2N3053

.50

.30

9/1.00

6/1.00 6/1 00

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 5/1.00 7/1.00 5/1.00 1.25 2/1.00

TRANSISTORS

FW BRIDGE HEC. FW BRIDGE REC.

2N305S

MJE3055

2N3392

2N339B

PN3567

PN3568

PN3569

MPS3638A

MPS3702

2N3704

MPS3704

2N.3705

MPS370S

2N3706

MPS3706

2N3707

2N3711

2N3724A

2N3725A

2N3772

2N3823

2N3903

5/1.00 5/1.00 3/1.00 4/1.00 4/1.00 5/1.00 5/1.00 5/1.00 5/1.00 5/1.00 5/1.00 5/1.00 5/1.00 5/1.00 5/1.00 .65 1.00

2N3904 2H3905 W3906 JN4013 2N4123 PN4249 PN4250 2N4400 2N4401 2N4402 2N4403 2N4409 2N5086 2IM5087 2N508B 2N50B9 2N5129 PN5134 PN5138 2N5139 2N5210 2N5449 2N5951

3/1.00 6/1.00 4/1.00 4/1.00 4/1.00 4/1.00 4/1.00 4/1.00 5/1.00 4/1,00 4/1.00 4/1.00 4/1.00

5/1.00

5/1.00 3/1.00

CAPACITOR

LS Ifeffl Mi

CORNER

47 pi

100 pl 220 pi 470 Dl

.OOlmf .0022 .0047ml .01ml

-1/35V

.15/35V 22/35V .33/35V .47/35V .68/35V 1.0/35V

.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

100/50V

220/25V

220/5DV

470/25V

1000/I6V

2200/16V

.OOVF .04 .03 .0047„F .04 03 01j»F .04 ,03 022fiF .04 .03 047,iF .04 035 JjtF 1B0 VOLT MYLAR FILM CAPACITORS

022ml

047ml

.07

,1ml

■22ml .33 .2

4-20*= DIPPED TANTALUMS (SOL10) CAPACITORS -28 .23 .17 1.5/35V m %

.ZB .23 .17 2.2/35V % j

.28 .23 17 3.3/25V .35 .3

.28 .23 r 4.7/25V .33 .2

,28 .23 .17 6.6/25V .49 .4

.28 .23 .17 15/25V .75 .6

.28 ,23 .17 22/6V -IS -6

MINIATURE ALUMINUM ELECTROLYTIC CAPACITORS

.15

.13

.47/25V .47/50V 1.0718V

1.0/25V 1.0/5OV 4.7/16V 4.7/25V 4.7/50V 10/16V 10/25V 10/50V 47/50V 100/16V 100/25V 100/50V 220/16V 470/25V

Radial Laid .15 .13

.28 .

V

244 BYTE February 1980

w* Continuity Tester and Flashlight

Convenient versatile tool for quickly checking continuity of dead circuits, switches, appliances, cords, fuses, motors, control equipment, coils and panel boards. Also tests circuits for low-resistance shorts and helps identify wires in multi-wire cables. Dozens of other uses. Plus the added convenience of a handy, durable flashlight. Uses two AA size penlight batteries (not furnished}. Insulated clip prevents accidental shorting to case. Alligator clip has 48" lead with plug.

RT300 *7.95

Ssi

MICROPROCESSOR COMPONENTS

CONTINENTAL SPECIALTIES

Logic Monitor

The Logic Monitor allows you to check logic levels on all 16 pins of any DTL, HTL, TTL, or CMOS device. It has a typ ical input impedance of 100K ohms and weighs a mere 3 oz. (85 grams!. It has an input volt, range of 4V to 15V and draws a max. of 100mA@10V

LM-1 $70.00

Willi

Proto Clips

ijiji

', T 14-PIN CLIP PC-14 . . . . S 4.50

16-PIN CLIP PC-16 . . . . S 4.75

24-PIN CLIP PC-24 .... S10.00

VfWt'll 40-PIN CLIP PC-40 .... $16.00

Ptoto Boards

PB-6 $17.95

£JZ£3l\ PB-100 19.95

PB-101 22.95

W% PB-102 26-95

TVMA PB-103 44.95

PB-104 55.95

PB-203 99.95

PB-203A 155.00

PB-203A-Kit . . . 131.00

Jumbo 6-Digit Clock Kit

* Four .6J0"ht. and two .300"ht. common anode displays

* Uses MM5314 clock chip

* Switches for hours, minutes and hold ft

* Hours easily viewable to 30 feet

* Simulated walnut case

* 115VAC operation

* la or 24 hour operation

* Includes all components, case and wall

* Size: 6J/j x 3Vn x 1W

JE747 $29.95

■ Bright .300 ht. comm. cathode display

• Uses MM5314 clock chip

• Switches for hours, minutes and hold modes

• Hrs. easily viewable to 20 ft.

• Simulated walnut case

• 115 VAC operation

• 12 or 24 hr. operation

JE701

6-Digit Clock Kit $19.95

< 3-1/8" x 1M"

Regulated Power Supply

Uses LM309K. Heat sink provided. PC board con- — struction. Provides a solid 1 amp @ 5 volts. Can supply up to *5V, i9V and ±12V with JE205 Adapter. Includes components, hardware and instructions. Size: 3W x 5" x 2"H

JE200

$14.95

ADAPTER BOARD -Adapts to JE200+5V, ±9V and ±12V

DC/DC converter with +5V input. Toriodal hispeed switching XMFR. Short circuit protection. PC board construction. Piggy-back to JE 200 board. Size: 354" x 2" x 9/16"H

\JE205

$12.95

8212 8214 8216 8224 8226 8228 8238 8251 8253 B255 8257 6259

-8080A/S06QA SUPPORT DEVICESCPU

6-Bit Irput/Output

Priority Interrupt Control

Bi-Direflinnal Bus Driver

Clock Generator/Driver

Bus Driver

System Ccntrolier/Bus Driver

System Controller

Prog. Comm. J/0 (USART)

Prog. Interval Timer

Prog. Feriph. 1/0(PPIj

Prog. DMA Control

Prog. Interrupt Control —6800/BBDO SUPPORT DEVICES—

S 7 95 3.25 5.95 3.49

14.95 9.95 19.95 19.95

MICROPROCESSOR MANUALS

M-Z80 User Manual

-ROM'S

2513(2140) Cti3ractei Grieutnrl upper case)

2513(3021) Character (Jenerator(io*er case)

2516 Character Generator

MM5230N 2048-Bit Real Only Memory

MC680O MPU

MC6802CP MPU with Clock and Ram

MC6810AP1 128X8 Static Ram

MC6B21 Periph. Inter. Adapt (MC6820)

MC6828 Priority Interrupt Controller

MC683DL8 1024X8 Bit ROM (MC68A30-8)

MC6B50 Asynchronous Comm. Adapter

MC6852 Synchrcnous Serial Data Adapt.

MC6860 0-600 Dps Digital MODEM

MC6862 2400 ops Modulator

MC6880A Quad 3-State Bus. Trans. (MCBT26)

MICROPROCESSOR CHIPS—MISCELLANEOUS

Z80[7B0C) CPU |

Z80A{780-t) CPU

CDP1802 CPU MPU

2650 6502 8035

CPU

it MPU w/clock, RAM, 1/0 lines

TMS9900JL 16-Bit MPU vWhardware, mullipiy

& divide SHIFT REGISTERS

2101(8101)

2102

2IL02

2111(8111)

2112

2114

2114L

2114-3

2114L-3

5101

5280/2107

7489

74S20O

93421

UP0414

(MK4027) UP0416

(MK4116) TMS4344

45NL TMS4045 2117

256X1 1024X1 256X4 1024X1 1024X1 256X4 256X4 1024X4 1024X4 1024X4 1024X4 256X4 4096X1 16X4

MM500H

MM503H

MM504H

MM506H

MM510H

MM5016H

2504T

2518

2522

2524

2525

2527

2528

2529

2532

3341

74LS670

Dual 25 Bit Dynamic

Dual 50 Bit Dynamic

Dual 16 Bit Static

Dual 100 Bit 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 Static

Dual 250 Static

Dual 240 Bit Static

Quad 80 Bit Static

Filo

4X4 Register File (TriSlale)

$.50 MM5262

1702A

2716INTEL

TMS2516

(2716)

TMS2532

2708

2716T.I

5203 6301-1(7611) 1024 6330-1(7602) 256

- RAMS

Static

Dynamic

Sialic

Sialic

Sialic

Static

Sialic M0S

Static 450ns

Static 450ns low power

Static 300ns

Static 300ns low power

Static

Dynamic

Static

Sialic Trislale

Static

Dynamic 16 pin

Dynamic 16 pin 250ns

Sialic

1024X4 Static 16.384X1 Dynamic 350ns (house marked) 2KX1 Dynamic

PROM'S

2048 FAM0S

IW EPROM

IbK' EPROM

"Requires single +5V power supply 4KX8 EPROM

8K EPROM

16K" EPROM

Requires 3 voltages. —5V. +5V. +12V 2048 FAM0S

9.95 14.95

$5.95 59.95 4995

8995 10.95 29 95

82S23 82S115 82S123

32X8 4096 32X6

A-V-5-1013 30K6AUD

Trislate Bipolar

Open C Bipolar

Open Collector

Bipolar

Trislate

TTL Open Collector

TTL Open Collector

Sialic

JE600 HEXADECIMAL ENCODER KIT

FT

I

FEATURES:

• Full 8 tort latched Output lor microprocessor use

• 3 User Define keys with one being bistable operation

■ Debounce circuit provided lor all 19 keys

mector

i tries

indard 16 pin

■5VDC required lot operations FULL 8 BIT LATCHED OUTPUT—19 KEYBOARD The JE600 Encodei Keyboard provides two separate beiadecimal digits produced Irom sequential key entries lo allow direct programming lor 6 bil microprocessor or 8 bit memory cucuils Three (3) addilional keys are provided tor user operalions with one having a bisiabie oulput available. The outputs are latched and moniiored wiih LED readouts Alsc- included is a key eniry strobe

JE600 $59.95

Hexadecimal Keypad only $14.95

DIGITAL THERMOMETER KIT

■ Dual sensors—switching control for indoor/outdoor or dual monitoring

• Continuous LED .8" ht. display

■ Range: -40°F to 199°F / -40°C to 100°C ■Accuracy: ±1°nomlnal

■Set for Fahrenheit or Celsius reading ■Sim. walnut case - AC wall adapter Incl. ■Size: 3-1/4"Hx6-5/8"Wx1-3/8"D

JE300 $39.95

62-Key ASCII Encoded Keyboard Kit

The JE610 62-Key ASCII Encoded Keyboard Kit can be interfaced into most any computer system. The JE610 Kit comes complete with an industrial grade keyboard switch assembly {62 keys), IC's, sockets, connector, electronic components and a double-sided printed wiring board. The keyboard assembly requires +5V @ 150mA and —12V @ 10mA for operation.

FEATURES:

•60 Keys generate the full 128 characters, upper and) tower case ASCII sat

• Fully buffered

• 2 user-define keys provided for custom applications

• Caps lock for upper case only alpha characters

•Utilizes a 2376 (40 pin) encoder

read only memory chip •Outputs directly compatible with

TTL/DTL or MOS logic arrays •Easy interfacing with a 16-pin dip

or 18-pin edge connector

JE610 $79.95

62-Key Keyboard only. .$34.95

HICKOK

LX303 Portable LCD Digital Multimeter

• lOthnV ucfsv

™..™fn

(r.,i,;'.i*

LX303 Digital Multimeter $74.95

RC-3 116V AC ADAPTE R 7.50

CC-3 PADDED CARRYING CASE 7.50

VP-10 X10 DC PROBE ADAPTER (Up lo I OK] , 14.95

VP-40 40kV DC PROBE 35.00

CS-1 10 Amp DC Current Shun! 14.95

$10.00 Min. Order - U.S. Funds Only Spec Sheets - 25rf

Calif. Residents Add 6% Sales Tax 1980 Catalog Available -Send 41^ stamp

Postage —Add 5% plus$1 Insurance (if desired)

■ ■■■■■■^■H PHONE

ISoA lameco woersse

MAIL ORDER ELECTRONICS - WORLDWIDE

1355 SHOREWAY ROAD, BELMONT, CA 94002

ADVERTISED PRICES GOOD THRU FEBRUARY

The Incredible "Pennywhistle 103"

v>l0y.95 Kit Only

Thn Pennywtilttfe 103 is capable cf recording data lo anil from audio tape without

critical speed requirements tor the recorder and it is able to communicate directly with

another modern and terminal (or ;elephone "hamming" and communications. In

addition, it isf ree of critical adjustments and is built with non-precision, readily available

parts.

Data Transmission Method Frequency-Shift Keying, full-duple* (half-duplex

selectable).

Maximum Dafa Rate 350 Baud,

Dala Formal Asynchronous Serial (return !o mark level required

between each character). Racslw Channel Frequencies .. .2025 Hz for space; 2225 Hz for mark. Transmit Channel Frequencies ..Switch selectable: Low (normal) = 1070 space,

1270 mark; High = 025 space, 2225 mark.

Receive Sensitivity -46 dbm acoustically coupled.

Transmll Laval -15 dbm nominal. Adjustable from -6 dbm

to -20 dbm. Racaiva Frequency TolBrance ...Frequency reference aulomaiically adjusts to

allow for operation between 1 BOO Hz and 2400 Hz. Digital Dala Inlerface EIA RS-232C or 20 mA current loop (receiver is

optoisolated and non-polar).

Power Requirements 120 VAC, single phase. 10 Watts.

Physical All components mount on a single 5" by 9"

piinted circuit board. All components included. Requires a VOM, Audio Oscillator, Frequency Counter and/or Oscilloscope lo align

TRS-80 16K 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 requiredjust wrap

Wire

Part No. JW-I-B

JW-1W JW-1-Y JW-1-R

White Yellow Red

Prica

$14.95 14.95 14.95 14.95

JUST UURAP" Replacement Wire

Pan No.

R-JW-B R-JW-W R-JW-Y R-JW-R

Blue 50 ft. ,

White 50 ft.

Yellow 50 ft. i

Red 50 ft. i

Pries

$2.98 2.98 2.98 2.98

JUST WRAP' Unwrap Tool $3.49

JUST Ul/RAP" Kit «50 ft. ea: blue, white, red. yellow wire • JUST WRAP Tool •Unwrapping Tool

JWK-6 $24.95

Vacuum Vise

Vacuum-based light-duty vise for small components and assemblies. AFJS construction. 1«" jaws, 1J4" travel.Can be permanently installed.

VV-1 $3.49

EPROM Erasing Lamp

•Erases 2708, 2716, 1702A, 5203Q, 5204Q, etc. •Erases up to 4 chips within 20 minutes. •Maintains constant exposure distance of one inch

Special conductive foam liner eliminates static build-up •Built-in safety lock to prevent UV exposure • Compact - only 7-5/8" x 2-7/8" x 2"

Complete with holding tray for 4 chips

UVS-11E $69.95

■P

-©■

JOYSTICK

•2 each 100K pots (Linear

Taper) •Printed Circuit Board

Mount •Size: 1" x 1-3/16" x 1-3/16"

JOYSTICK .

$4.95 J

Circle 217 on inquiry card.

BYTE February 1980 245

One-Stop Component Center AUTHORIZED DISTRIBUTORS

ALABAMA

Cropwell Tucker Bros.

Huntsville Industrial Electronic Supply

Mobile Lafayette Radio Electronics ALASKA

Anchorage The Electronic Company

Anchorage TV Mart ARIZONA

Flagstaff Jim's Audio & Stereo Repair

Sierra Vista B & S Electronics

Yuma Yuma Electronics ARKANSAS

Little Rock Southern Electronics Company

CALIFORNIA

Anaheim Heathkit Electronic Center

Azusa Amco Electronics

Bellflower Earl's Hobby Shop

Berkeley At Lasher Electronics

Brea Century Electronics

Buena Park Ford Electronics

Buena Park S.J. Electronics

Chula Vista Lion Electronics

Cypress SCR Electronics Davis Paradyne Consumer Electronics

El Mon te Kimball & Stark

Fontana Fontana Electronics

Fresno Sparky Electronics

Glendale Eagle Electronics

Harbor City Buff's Electronics

Hawaiian Gardens Carson Electronics

Hollywood Pacific Radio Exchange

La Habra A.B.C. Electronics

Lancaster Consumer Electronics

Long Beach Scott Radio Supply Inc.

Mission Viejo Tower Electronics Corp.

Modesto Computer Magic

Modesto Pacific Radio

Mon terey Zackit

Morro Bay Coast Electronics

National City Willy's Electronics

Oceanside Electronic Center

Oxnard Dow Radio

Palmdale Radio Shack A. S. C Palmdaie

Palo Alto U.S. Electronics

Palo Alto Zack Electronics

Pasadena Dow Radio inc.

Paso Robles Mission Electronics

Redding Radio Mart

Sacramento Heathkit Electronic Center

Sacramento Zackit

Salinas Salinas Radio

San Carlos J&H Outlet Store San Diego Radio Shack A.S.C. Mira Mesa

San Diego Byte Shop

San Fernando San Fernando Electronics

San Francisco Zack Electronics San Jose Peninsula Electronic Supply Inc.

San Jose United Radio & TV Supply San Luis Obispo Mid-State Electronic Supply

San Rafael Electronics Plus

Santa Barbara Lombard Electronics

Santa Cruz Santa Cruz Electronics

Santa Fe Springs Industrial Electronics

Santa Maria Cap's Communications

Santa Rosa Electronics Inc.

South Lake Tahoe CalPine Electronics

Suisun City Byte Shop

Sunnyvale Sunnyvale Electronics

Torrance SE Electronics

Torrance Torrance Electronics

Vacaville D.C. Electronics

Vallejo Zackit Van Nuys Thrifty Electronics Supply Inc.

Walnut Creek MicroSun Computer Center

Westminster JK Electronics

Whittier D & S Electronics

Whittier Whittier Electronics Company COLORADO

Aurora Aurora Electronics Colorado Springs Centennial Electronics Inc.

Denver Amp tec Inc.

Denver Mt. Coin Distributing Co. CONNECTICUT

Avon Heathkit Electronic Center

Bridgeport Bridgeport Computer

Milford Daz Electronics New Haven Customized Computer Systems

Westport Computerworks DELAWARE

New Castle Delaware Amateur Supply FLORIDA

Ft. Lauderdale Computers For You

Gainesville Lafayette Radio

Hialeah Heathkit Electronic Center Lakeland Lakeland Specialty Electronics

Miami Herman Electronics

Miami N & G Distributors

Oakland Park Lafayette Radio

Orlando Southeast Micro-Data Corp.

Panama City Bay-Mar Electronics Inc.

Pensacola Grice Electronics Inc.

Tampa AMF Electronics

Tampa Microcomputer Systems

GEORGIA

Atlanta

A tlan ta

Columbus

Stone Mountain

HAWAII

Aiea

Honolulu

IDAHO

Boise

Caldwell

ILLINOIS

Carbonda/e

Decatur

Evanston

Gro veland

Atlanta Computer Mart

CompuShop

Radio Wholesale

Coleman's Electronics

Delcoms Hawaii Integrated Circuit Supply

Custom Electronics A-Gem Supply Inc.

Picks Electronics Main Street Computer Co. Tri-State Electronic Corp. Moyer Electronics

MICHIGAN (Continued)

Pontiac Electronic Supply

Port Huron Main TV Radio Electronics Inc.

Saginaw Electronic Mart

St. Clair Shores Bell Electronics

Sterling Heights Lafayette Radio

Traverse City Traverse City Electronic Supply

Mount Prospect Tri-State Electronic Corp.

Niles Computer Land

Normal B-N Computer Works

Peoria Computer Land of Peoria

Peoria Warren Radio Co.

Rockford Computer Store of Rockford

Schaumburg Data Domain of Schaumburg

Skokie 'Lilfpuie Computer

Villa Park Melvin Electronics INDIANA

East Chicago Aero Electronics Carp.

Evansville Hutch & Son Inc.

Gary Caliimet Electronic Supply IOWA

Ames Electronic Supply Inc. Clinton Bridge Electronics Computer Center

Davenport Memory Bank

Des Moines Gifford Brown Incorporated

Des Moines Radio Trade Supply Co. KANSAS

Hutchinson Hutchinson Electronics

Kansas City Electronic Surplus Sales

Mission Heathkit Electronic Center

Salina Electronics Inc. Wichita Amateur Radio Equipment Co. KENTUCKY

Lexington Radio Electronic Equipment Co.

Louisville Peerless Electronic Equipment Co.

Richmond Madison County Electronics LOUISIANA

Baton Rouge Davis Electronics Supply CoBaton Rouge Menard Electronics Inc. Baton Rouge Pelican Electronics Houma Pelican Electronics Lake Charles Wholesale Radio & Equipment Metairie Pelican Electronics New Orleans Wm. B. Allen Supply Co. MARYLAND

Annapolis J & M Electronics Inc.

Baltimore American Distributing Co.

Baltimore Everything Electronic

Baltimore Harco Electronics

Baltimore Tritronics Inc.

Churchville Churchville Electronics

Damascus Damascus CB Frederick Frederick Computer Products Inc.

Glen Burnie Revacto

Hagerstown Custom Computing Inc.

La Vale J & M Electronics

Rockvil/e Computer Workshop

Rockvilie Heathkit Electronic Canter

Silver Spring Computers Etc.

Towson BaynesvUla Electronic Inc.

Towson Computers, Etc.

Towson Computers Unlimited

Towson Heathkit Electronic Center MASSACHUSETTS

Peabody Heathkit Electronic Center

Pittsfield Pittsfield Radio Co. Inc.

Waltham Computer Mart Inc.

Wellesley Heathkit Electronic Center

Worcester RM Electronics Inc. MICHIGAN

Adrian E & B Electronics inc.

Ann Arbor Lafayette Radio

Ann Arbor Wedemeyer Electronic Supply

Bay City Kinde Distributing Company

Canton The Electronic Connection Clawson Radio Supply & Engineering Co.

Detroit Heathkit Electronic Center

East Detroit Heathkit Electronic Center

East Lansing Lafayette Radio

Flint Hobby Electronic Center

Flint Shand Electronics Inc.

Garden City Computer Center

Grand Rapids Micro Computer World

Grand Rapids Radio Parts Inc.

Grand Rapids Warren Radio Company

Jackson Fulton Radio Supply

Lansing Fulton Radio Supply Co.

Livonia Lafayette Radio Livonia Radio Supply & Engineering Co. Inc.

Midland Computronix Corporation

Milan C& S Electronics Mart Ltd.

Muskegon H.R. Electronics

Niles Niles Radio Supply

Oak Park Lafayette Radio

MINNESOTA

Duluth

Hopkins

Minneapolis

St Paul

Winona

MISSOURI

Bridgeton

El Dorado Springs

Florissant

MONTANA

Billings

Northwest Radio of Duluth Inc.

Hedthkit Electronic Center

Pal Electronics

Heathkit Electronic Center

Hiawatha Electronics Inc.

Forsythe Computers

Beckman Electronics

Computer Country

Bozeman Electronic Sarvice & Distributing Inc.

Great Falls NEBRASKA

L incoln

Lincoln

North Platte

Omaha

Omaha

NEVADA

Las Vegas

NEW JERSEY

Cherry Hill

Fair Lawn

Ocean

Pennsauken

Pompton Lakes

Ramsey

Vineland

NEW MEXICO

Farmington

NEW YORK

Albany

Albany

Albany

8/oomington

Buffalo

Cortland

Endwell

Ithaca

Jamestown

Jericho

Kingston

Kingston

Middletown

Newburgh

New York

New York

Orchard Park

Peek skill

Poughkeepsie

North White Plains

Rensselaer

Conley Radio Supply

Arts Electronics

Altair Computer Center

Scott Electronic Supply Inc.

Scott Electronic Supply Corp.

Heathkit Electronic Center

Omaha Computer Store

Rochester

Troy

Utlca

Vestal

Wappingers Falls

White Plains

NORTH CAROLINA

Greenville

Morehead City

Raleigh

NORTH DAKOTA

Fargo

Fargo

OHIO

Bucyrus

Cincinnati

Columbus

Reynoldsburg

Toledo

Wick/iffe

Youngstown

OKLAHOMA

Oklahoma City

Oklahoma City

Oklahoma City

Tulsa

OREGON

Albany

Beaverton

Corvallis

Eugene

Ontario

Portland

Salem

Salem

PENNSYLVANIA

Braddock

Chambersburg

Drexel Hill

Drums

Erie

Century 23

The Computer Emporium Heathkit Electronic Center Heathkit Electronic Center Lafayette Radio Computer Corner Typetronic Computer Store Lafayette Radio Electronics

Micro-Computer Service

Fort Orange Electronics

Action Audio Inc.

Greylock Electronics

Stansifer Radio Co. Inc.

Radio Equipment Corp.

Action Audio Inc.

Computer Tree Inc.

Action Audio Inc.

Warren Radio

Heathkit Electronic Center

Action Audio Inc.

Greylock Electronics

Action Audio Inc.

Action Audio Inc.

Aristo Craft

Manhattan Electronics Corp.

Radio Equipment Corp.

Action Audio Inc.

Greylock Electronics

Heathkit Electronic Center

Corn-Tech Electronics

Heathkit Electronic Center

Trojan Electronics

Am-Com Electronics

Harvey Electronics

Action Audio Inc.

The Computer Corner

Pair Electronics

Baer Electronic Systems

Byte Shop of Raleigh

The Computer Company S& S Electronics

Mead Electronics Heathkit Electronic Center Heathkit Electronic Center Universal Amateur Radio Heathkit Electronic Center Amateur Electronic Supply Ross Radio Company

Bits, Bytes & Micros Heathkit Electronic Center Trice Wholesale Electronics

High Technology

PENNSYLVANIA (Continued)

Philadelphia Heathkit Electronic Center Philadelphia Resco Electronics (Market St.)

Phoenixville Stevens Electronics

Pittsburgh Heathkit Electronic Center

Pittsburgh Tydings Company

Wilkes Barre Hamline Electronics

York G.Y.C. Company RHODE ISLAND

Cranston Jabbour Electronics City

Pawtucket Jabbour Electronics City

Warwick Heathkit Electronic Center TENNESSEE

Clarksville Masstronics

Cookevil/e Wagnon's Stereo Center

Nashville Electra Distributing Co. Knoxvi/le Shields Electronics Supply Inc.

Memphis Bluff City Electronics Memphis Sere-Rose & Spencer Electronics

Memphis Warren Radio Company Nashville Eddie Warner's Parts Company

Oakridge National Electronics

Tullahoma H & H Electronics Co. Inc. TEXAS

Beaumont Electro-Hut

Dallas CompuShop

Dallas Heathkit Electronic Center

Dallas Ram Micro Systems

Fort Worth The Ingenuity Concept

Houston Interactive Computers

McAllen Broadway Electronics

McAllen Carlos Franco Electronics

San Antonio Appliance & Equipment Co. San Antonio Sherman Electronics Supply Inc. UTAH

Midvale Heathkit Electronic Center

Provo Alpine Electronic Supply Co.

Salt Lake City Best Distributing

Salt Lake City Computer/and of Salt Lake VERMONT

Essex Junction Lafayette Radio VIRGINIA

Alexandria Computers Plus Inc.

Alexandria Heathkit Electronic Center Arlington Arlington Electronic Wholesalers

Blacksburg Scotty's Radio & TV Inc.

Charlottesville Graves Electronics

Colonial Heights Southside Radio Comm.

Falls Church Crossroad Electronics

Hampton Electronic Sales Inc.

McLean Tyson's Computer Emporium

Norfolk Avec Electronics Corp.

Norfolk Priest Electronics

Portsmouth Electronics Unlimited

Richmond Avec Electronics Corp.

Vienna Electronic Equipment Bank

Virginia Beach Heathkit Electronic Center

Warrenton Radio Shack WASHINGTON

Bellevue ABC Communications

Everett ABC Communications

Kennewick C & J Electronics Inc.

Longview Progress Electronics

Moses Lake Ron's Electronics

Pasco Riverview Electronics

Richland C & J Electronics

Seattle ABC Communications

Seattle Amateur Radio Supply

Seattle Empire Electronics

Spokane Personal Computers

Tacoma C & G Electronics

Tacoma Northwest Radio Supply WEST VIRGINIA

Morgantown The Computer Corner

Morgantown Electro Distributing Co. Inc. Wheeling Lafayette Radio Associate Store WISCONSIN

West AIUs Olson Electronics

Paoli

Oregon Ham Sales

Norvac Electronics

Zero-Gee Books

Eugene Amateur Radio Supply

Miller Electronics

Portland Radio Supply

Comm-Shack

Computer Pathways

Left Electronics

Sunrise Electronic Distributing

Kass Electronics Distributors

Mr. D's Digital Electronics

Warren Radio

CompuShop Alberta Ltd.

Personal Computer Corporation

CANADA

Alberta:

Calgary

British Columbia:

Prince George Elwest Technical Services Ltd.

Vancouver CompuShop

Ontario:

Toronto House of Computers

ENGLAND

Berkshire NewBear Computing Store

GUAM Marianas Electronics

PANAMA

Panama City Sonitel, S.A.

Panama City Tropelco. S.A.

SINGAPORE Applied Digital System

SINGAPORE Inter-Trade <PTE.) Ltd.

SINGAPORE Sys-Tech

SWEDEN

Stockholm LSI Electronics HB

Umea tnterkomponent

WEST INDIES

Port of Spain, Trinidad The Hobby Centre

For Distributor Information, write or phone JIM-PAK® 1355 Shoreway Road, Belmont, CA 94002 (415) 592-8097

246 BYTE February 1980

Jag Quality Kits

Function Generator Kit

Provides three basic waveforms: sine, triangle and square wave. Frequency range from 1 Hz to 100K Hz. Output amplitude from 0 volts to over 6 volts (peak to peak). Uses a 1 2V supply or a ±6V split supply. Includes chip, P.C. Board, components & instructions.

JE2206B $19.95

Digital Thermometer Kit

Dual sensors — switching control for indoor/outdoor or dual monitoring. Continuous LED .8" ht. display. Range: -40°F to 199°F / -40°C to 100°C. Accuracy ±1° nominal. Set for Fahrenheit or Celsius. Simulated walnut case. AC wall adapter included. Size: 334"h x 6-5/8"w x 1-3/8"d.

JE300 $39.95

Digital Stopwatch Kit

PDCKfc T SlUFfeffTTii

Use Intersil 7205 Chip. Plated thru double-sided P.C. Board, Red LED display. Times to 59 minutes, 59.59 seconds with auto reset. Quartz crystal controlled. Three stopwatches in one: single event, split (cummulative) and taylor (sequential timing). Uses3penlite batteries.

Size: 4.5" x 2.15" x .90"

JE900 $39.95

4-Digit Clock Kit

6-Digit Clock Kit

Jumbo 6-Digit Clock Kit

Bright .357" ht. red display. Sequential flashing colon. 12 or 24 hour operation. Black extruded aluminum case. Pressure switches for hours, minutesand hold functions. Includes all components, case and wall transformer. Size: 3'A" x 1 %" x 1 S4"

JE730 $14.95

Bright .300 ht. common cathode display. Uses MM5314 clock chip. Switches for hours, minutes and hold functions. Hours easily viewable to 20 ft. Simulated walnut case. 11 5VAC operation. 1 2 or 24 hour operation. Includes all components, case and wall transformer. Size: 6%" x 3-1/8" x 1%"

JE701 $19.95

Four .630" ht. and two .300" ht. comm. anode displays. Uses MM5314 clock chip. Switches for hrs., mins., and hold functions. Hours viewable to 30 ft. Sim. walnut case. 11 5VAC operation. 1 2 or 24 hour operation. Incl. all components, case and wall transformer. Size: 6%" x3-1/8" x 1%"

JE747 $29.95

Regulated Power Supply Kit

Multi-Voltage Board Kit

Variable Power Supply Kit

Uses LM309K. Heat sink provided. PC board construction. Provides solid 1 amp @ 5 volts. Includes components, hardware & instructions. Size:3H"x5"x2"h

i tfJ

^t

ADAPTS TO JE200 SUPPLIES ±5V, ±9V and ±12V

Independent load rating at single terminal. ±12V:160mA, ±9V:200 mA, -5V:250mA. DC/DC converter with +5V input. Toriodal hispeed switching XMFR. Short circuit protection. PC board construction. Piggy-back to JE200 board. Size: 31/s" x 2" x 9/16"h

Full 1.5 amp @ 5-10V output. Up to .5 amp @ 15V output. Heavy duty transformer. Three-terminal I.C. voltage regulator. Heat sink provided for cooling efficiency. PC board construction. 120VAC input. Size: 31/3" x 5" x 2"h

JE200 $14.95

JE205 $12.95

JE210 $19.95

62-Key ASCII Encoded Keyboard Kit

The JE610 ASCII KEYBOARD KIT can be interfaced into most any computer system. The JE610 kit comes complete with an industrial grade keyboard switch assembly (62-keys), IC's, sockets, connector, electronic components and a doublesided printed wiring board. The keyboard assembly requires +5V @ 150mA and —12V@ 10mA for operation. Features: 60 keys generate the full 128 characters, upper and lower case ASCII set. Fully buffered. Two user-define keys provided for custom applications. Caps lock for upper case-only alpha characters. Utilizes a 2376 (40-pin) encoder read-only memory chip. Outputs directly compatible with TTL/DTL or MOS logic arrays. Easy interfacing with a 16-pin dip or 18-pin edge connector.

JE610 $79.95

Hexadecimal Encoder Kit

i%

M

FULL 8-BIT LATCHED OUTPUT - 19-KEY KEYBOARD The JE600 ENCODER KEYBOARD provides two separate hexadecimal digits produced from sequential key entries to allow direct programming for 8-bit microprocessor or 8-bit memory circuits. Three (3) additional keys are provided for user operations with one having a bistable output available. The outputs are latched and monitored with 9 LED readouts. Also included is a key entry strobe. Features: Full 8-bit latched output for microprocessor use. Three user-define keys with one being bistable operation. Debounce circuit provided for all 19 keys. 9 LED readouts to verify entries. Easy interfacing with standard 16-pin IC connector. Only +5VDC required for operation.

JE600 $59.95

(Prices Subject To Change)

Circle 218 on inquiry card.

BYTE February 1980

247

ISEE OUR 52 PAGE AD IN JANUARY BYTEl

DISC DRIVES

SD EXPANDORAM The Ultimate S-100 Memory

The EXPANDORAM is available in versions from 16K up to 64K, so for a minimum Investment you can have a memory system that will grow with your needs. This Is a dynamic memory with the Irtvlsable onboard refresh, and IT WORKS!

IMSAI. SOL-8, Cromenco.

. ~.rJ&W&:...^-

'WB*\~*U"\ gH^jwr^

EXPANDO 64

List Price

$385.00

$550.00

$715.00

$880.00

16K 32 K 48 K 64 K

KIT (4116): Sale Price

$239.00 $309.00 $379.00 $449.00

Bank Selectable

Phantom

Power 8VDC, ± 16VDC, 5 Watts

Lowest Cost Per Bit

Uses Popular 4116 RAMS

PC Board Is doubled solder masked and has

silk-screen parts layout.

Extensive documentation clearly written

Complete Kit Includes all Sockets lor 84K

Memory access time: 375ns, Cycle time: 500ns.

No wait states required.

16K boundrles and Protection via Dip Switches

Designed to work with Z-BO, 8080, 8050 CPU's

P

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DISC CONTROLLER SD "VERSAFLOPPY" KIT

The Versatile Floppy Disk Controller List Price $250.00 SALE PRICE

$189.95

VERSAFLOPPY II

DOUBLE DENSITY, DOUBLE SIDED, DISC.CONTROLLER

GENERAL DESCRI Veisalloppy II is I controller that in

inch diskette'and 129,9Z0 bytes per side on a live inch minidiskette The Varsalloppy II direclly conttols many popular disk drives. These Include: Shugarl SA400 and SA450; Shugart SA0OO and 5A850; Mayllower MFESOO and MFE700: Per Sci 70 and 277; and Siemans, B5I-105.

• S-100 BuslEEE Standard Compatible

• IBM3740 Compatible Soft Sectored Formal tor Single

ividos Control lor Double

led Operation

eiates with Z80, 8080, and 8085

SDS-VERSAFLOPPYII KIT List Price Sale Price

$350.00 $325.95

SDOS Disk Operating Sysler

SHOP & COMPARE SPECIAL

M-XVI

The true 16K Static Ram module

(or S-100 bus systems.

ASSEMBLED ft TESTED - 100% BURN IN The M-XVI gives you unbelievable expansion capability la' youl 5 too •,.,$ system oven beyond 64K. Mani.iact.te:] to mo b gtmst .nd.stty sian

iobt),

m m

FEATURES '

• Fully static

• Uses popuia'

• + 5 voll opet

• Bank Select . and bank byt.

•Phanlom line capability •Addre

201BBA 450ns 2MHZ Reg.$349.95 2016BB 300ns 4MHZ Reg.$389.95 2016BY Bare Board only

■o addie

Sale Priced $295.00 $329.00 $29.95

•FR.4 epoxy PC boards

THE MICROBYTE M32KSS 32K STATIC MEMORY BOARD ASSEMBLED & TESTED *

SAVE $120.00

• Fully S500 Bus Compatible, IMSAI, SOL, ALTAIR. ALPHA MICRO, • Uses National's Low Power 5257 4Rxl Static Rams • 2 MHz or dMHz operation. • Gold contacts for higher reliability. • On board single 5 amp regulator. • On board single 5 amp regulator • Thermally designed heat sink (board operating temperature 0° — 70°C} ■ Commercially designed power bus. 7 ground bus bars, 0.I ul decoupling capacitors. ■ Fully trlslate buttered. • Inputs fully low power Shottky Schmilt, Trigger buffered on all address and data lines. ■ Phantom is |umper selectable to pin 67

• Each <tK hardware or software selectable. • One on board 6-bit output port enables or disables the 32K in 4K blocks ■ Selectable port address. ■ 4K banks can be selected oi disabled on power on clear or reset. ■ Will operate with or without front panel • Compatible with ALPHA MICRO, with extended memory management for selection beyond 64K • No DMA restriction. ■ Low power consumption 2 3-25 amps. • Fully warranted for 120 days from date of shipment

ASSEMBLED & TESTED shipping weight 2 lbs

M32 KSS-H (4 MHz)

List $680

SALE $560.00

M32 KSS-L (2 MHz)

List $650

SALE $530.00

IO

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With On-Board RAM, PROM, CTC

• S-100 Bus Compatible

• Z80 Central Processing Unit

• 1024 Bytes of Random Access Memory

• 8K Bytes of PROM using 2716

• Parallel Input and Output Ports

• Four Channel Counter/Timer (Z80-CTC)

• Software Programmable Baud Rate Generator

• No Front Panel Required for Operation

List Price Sale Price

SDS-SBC-100 2MHZ KIT. $295.00 $249. 95 SDS-SBC-200 4MHZ KIT.$320.00 $289.95

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VDB-8024 VIDEO DISPLAY BOARD

With on-board Z80 Microprocessor

S-100 bus Compatible

Full 80 Characters by 24 Lines Display

Characters Displayed by High Resolution 7 x 10

Matrix

Composite or TTL Video Output

Keyboard Power and Interface

Forward and Reverse Scrolling Capability

Blinking, Underlining, Field Reverse,

Field Protect and Combinations

Full Cursor Control

96 Upper and Lower Case Characters

32 Special Character Set

128 Additional User Programmable Characters

(Optional)

On-Board Z80 Microprocessor

2K Bytes Independent On-Board RAM Memory

Glitch-Free Display

List Price Sale Price

SDS-VDB-8024 KIT $370.00 $329.95

»f*S»lBS

PROM-100

Programming Board for PROM Development

NEW

SD SYSTEMS' PROM-100 is a versatile PROM pre gramming board offering complete EPROM programming capability. The board operates on the industry standard S-100 Bus. Support software verifies the erasure of EPROM and verifies the loaded program. SD SYSTEMS' PROM-100 offers a support-software listing with its operations manual.

• S-100 Bus Compatible

• Programs the Following EPROM s: 2708, Intel 2758, 2716, 2732 and Texas Instruments 2516

• Dip Switch Selection of EPROM type

• 25 VDC Programming Pulse Generated On Board

• Maximum Programming time: 16,384 Bits in 100 Seconds

• Power Requirement: +8VDC at 300 ma.;

+ 16 VDC atr 100 ma.; - 16 VDC at 60 ma.

• TTL compatible

• Software Provides for Reading of Object File from SDOS, CP/M or PROM and Programming into EPROM

• Program Verification • Verification of Erasure

• Zero Insertion Force Socket

List Price Sale Price

SDS-PROM-100 KIT.$200.00 $1-75.00

PRIORITY ONE ELECTRONICS®

16723K Roscoe Blvd. Sepulveda, CA 91343

Terms: Visa, MC, BAC, Check, Money Ordar, CO.D. U.S. Funds Only. CA residents add 6% 3ales ta: Minimum order $10.00 Prepaid U.S. orders less than $75.00 include 5% shipping and handlinj MINIMUM $2.50. Excess refunded. Just in case . . . please include your phone no. Prices subject to change without notice. We will do our best lo malnlain prices thru Feb. 1980 OEM and Institutional

phone orders welcome (213) 894-8171, (800) 423-5633 inquiries invited.

%

800423-5633

EXCEPT

CA.AK.HI.

(213)894-8171

Z80 STARTER KIT A Complete Microcomputer On A Board

• Z80 CPU with 158 Instructions

• On-Board Keyboard and Display

• On-Board PROM Programmer for Single Voltage PROMS (2716, 2758, TI2516)

• Kansas City Standard Cassette Interface

• Simple Key Controlled Audio Cassette Load and Dump

• Expansion Provision for Mounting Two S-100 Connectors (Sockets Not Included)

• Wire Wrap Area for Custom Circuitry

• Single Step through RAM or PROM

• Memory Examine and Change

• Port Examine and Change

• Z80 CPU Register and Change

• 2K Byte ZBUG Monitor in ROM

• IK Bytes of RAM (Expandable to 2K Bytes)

• A 4 Channel Hardware Counter/Timer (Z80-CTC)

• Two Bi-Directional 8-Bit I/O Ports (Z80-P10)

• Up to 5 Programmable Breakpoints

• Switch Selectable PROM or Monitor Restart

• Vectored Interrupts provided by Z80-CTC and

List Price Sale Price

SDS-Z80 STARTER KIT $340.00 $279.95

ORDER TOLL FREE 1-800-423-5633 ORDER TOLL FREE 1-800-423-5633

248 BYTE R-bruarv

ISEE OUR 52 PAGE AD IN JANUARY BYTEl

4 MHZ EXPANDORAM II KIT

The S-100 Memory Board for the 80's

SD SYSTEMS' ExpandoRAM II is a state-of-the-art • S-100 Bus Compatible

dynamic RAM board with capacities from 16K bytes • Up to 4Mhz Operation

(4116) to 256K bytes (4164). It operates on the industry • Expandable Memory from 16K to 256K

S-100 Bus. The ExpandoRAM N's design allows eight, • DIP Switch Selectable Boundaries

*ty

boards to operate from the same S-100 Bus. Page mode operation provides the system with the capability of servicing multiple users without RAM interference. Invisible refresh and synchronization with wait states provide greater reliability, and processing speeds up to 4 Mhz.

The ExpandoRAM II is compatible with most S-100 CPU's based on the Z80 microprocessor. When other SD SYSTEMS 200 series boards are combined with the ExpandoRAM II, they create a microcomputer with exceptional capabilities and features.

Uses 16K (4115) or 64K (4164) Memory Devices

Page Mode Operation Allows up to 8 Memory

Boards on Bus

Operates with Z80 CPU's

Phantom Output Disable

Invisible Refresh (Synchronized with

Wait States)

SDS ■ EXPANDOPRAM II KIT (4116)

List Price Sale Price List Price Sale Price

16K . . . $460.00 $295.00 48K . . . $960.00 $445.00 32 K . . . $710.00 $370.00 64K . . $1210.00 $520.00

8803

lonlof 4

5. ♦ I!.

MOTHER

UttfffM

ramnwwwi

BOARD FOR

Wiring si

e snown Com

S100 BUS

rjnntnl HM Dan tpoiy

MlCiiO

glass w>l

aSuom

,or COMPUTERS

SlOipn

glass Board wi

2 ounce.

In holes far loads

Soldo > m.

tithed a

recooiacies wiirt ioocomacis|2

I2S centers *U

250 row spacing.

Vecior w

number R68I■

.ormounis 10 rocep

IdCleStJlUSinlerCOrlneCllOi

includes

Ched Circuits a

dinslruclKjnstoroplion

es + SVdnuGNO<IOAMPS) ± 12V 0

AMPS] C

ireni ratings at

BeiHIL-STO-I75wim

Price: $29.50

Plugboards

8800V

Universal Microcomputer/processor plugboard, use with S-100 bus Complete with heat sink & hardware 5 3"* 10 x 1/16 ■

1-4 5-9 10-24

S19.95 $17.95 515.95

8801-1 Same as 8800V except plain: less power buses & beat sink

1-4 5-9 10-24

$15.22 $13.79 $12.18

3682 9.6" X 4.5"

$12.97

3682-2 6.5" X 4.5"

$9.81

Hi-Density Dual-ln-Line Plugboard for Wire Wrap with Power & Grd Bus Epoxy Glass 1/16" 44 pin con.spaced .156

3677 9.6"x4.5'

$10.90

3677-2 6.5" x 4.5"

$9.74

Gen. Purpose D.I.P. Boards with Bus Pattern tor Solder or Wire Wrap. Epoxy Glass 1/16" 44 pine n. spaced .156

ijiiil

mull

3662 6.5" x4.5"

$8.95

3662-2 9.6" x4.5"

$11.45

P pattern plugboards tor IC's Epoxy Glass 1/16" 44pincon, spaced .156

FMfl

IllllllllllP 3690-12 CARD EXTENDER Card Extender has 100 contacts 50 per side on .125 centers-Attached connector-is compatible with S-100 Bus Systems. $25.83 3690 6.5" 22/44 pin .156 ctrs. Extenders .... $13.17

m m m

en

to

> o

m >

CQ 1 (MSA) Style Card Guides S/S1.00

S1O0.WWG50n00Con1 125clts. 3 LEVEL VIAE WRAP 025" sq. posts on .250 spacd rows GOLD PLATED

S100SE 50/100 Con! 125 ctrs. PIERCED SOLDER EYELET Tails GOLD

1-4 5-9 10-24

15.00 S4.50 S4.00

S100-STG 50H0O Cont .125 ctrs. DIP SOLDER TAIL on 250 spaced tows lor VECTOR, IMSAI. CROMENCO mother boards GOLD plated

1-4 $4.10

S3.80

S100ALT 50/100 Conl .125 ctrs. SOLDER TAIL on HO spaced rows ALTAIR motherboards, GOLD plated. 1-4 5-9 10-24

$4.50 $4.25 $4.00

(or

Other Popular Edge Connectors

D2244-5SE 22/44 Conl .156 Ctrs.PIERCED SOLDER EYELET tails GOLD plated. 1-4 5-9 10-24

$3.00 $2.60 $2.20

RS232 & "D" TYPE CONNECTORS

P = Plug-Male S = Sockel-Female C = Cover-Hood

PART NO.

OE-9P

DE-9S

DE-9C

DA15P

DA15S

DA15C

DB-25P

DB-255

OB51212-1

DB1226-1A

DB110963-3

OC37P

DC37S

DC37C

DD50P

DD50S

DDS0C

D20418-S

9 Pin Female 9 Pin Cover 15 Pin Male 15 Pin Femal 15 Pin Covef 25 Pin Male 25 Pin Female

1 pc. Grey Hood

2 pc. Black Hood 2 pc. Grey Hood 37 Pin Male 37 Pin Female 37 Pin Cover 50 Pin Male 50 Pin Female 50 Pin Cover

rW&fc.

M

/^"""■'""Jh\

1 FEMALE ~I '

Hardware Set (2 pain

Connector lor CENTRONICS 700 SERIES:

Amphenol 57-30360 for back of Centronics 700 Series pri 1-4-59.00 5 up —$7 50

1.50 2.15 1.50 2.20 3.20 1.60 2.90 3.7S 1.65 1.90 1.80 3.95 5.75 2.20 4.95 7.50 2.50 1.00

1.30 2.05 1.30 2.00 3.00

2.60

2.50

3.65

3.40

1.40

1.20

1.60

1.50

1.55

1.35

3.80

3.60

nnil

b,m

1.95

1.75

4.75

4.50

7.20

6.90

2.20

2.10

1M6 VmOl BOARD m .042 dia holes on P» 0.1 spacing for IC's

Phenolic PRICE

PART NO. SIZE . 1-9 10-19

64P44XXXP 4.5x6.5" $1.56 $1.40

169P44XXXP 4.5x17" $3.69 $3.32

Epoxy Glass

64P44 84P44 169P44 169P84

4.5x6.5" 4.5XB.5" 4.5x17" 8.5x17"

$1.79 $1.61 $2.21 $1.99 $4.52 $4.07 $8.83 $7.95

3 LEVEL GOLD WIRE WRAP SOCKETS*

Sockets purchased in multiples of 50 per type may be combined lor best price. 1-9 10-24 25-99 100-249 250-999

8 pin 14 pin 16 pin 18 pin 20 pin 22 pin 24 pin 28 pin 40 pin

.40 .44 .55 .70 .90 .95 .95 1.25 1.65

.36 .43

.85 1.15 1.45

.55 .75

1.00 1.35

All sockets are GOLD 3 level closed entry. 2 level Tail Low Prolile. Tin Sockets and Dip Plugs available. CALL FOR QUOTATION.

NOVATION CAT ACOUSTIC MODEM

$174,95

Regular $198.00

• 0-300 Baud

• Bell 103

3M SCOTCH* BRAND DISKETTES

740-OP 1/single SolMI

740/2-OP 2/single Soft-It

7A0-32P "(single 32

7A0I2-32P 2r1single 32

741-0 Kdouble Soil

$3995 S75.00 $39.95 $75.00 $59.00

'44-OK 1/singlc Soli (TRS-00) $51.00" 44-10K 1/singlo Soft/10 $51.00"

44-16K 1/singlrj Sottm $51.00"

"Price includes Kas-etieMO Storage Box

a $5.00 Value (TRS-80)

"DON'T SETTLE FOR ANYTHING

LESS THAN SCOTCH"

TRS-80/APPLE MEMORY EXPANSION KITS

/HIK'c QAIUIQ *rom Leading Manufacturers

alio s MAivib (16Kx1 200/250ns)

8 for $75.00

Add $3.00 for programming Jumpers

for TRS-80 Keyboard

Answer, Originate

PRIORITY

PRICE: S18.98

S same as 31[rlth 14" bar to

accomodate "S100"

boards.

PRICE: S19.98

PRICE:S14.49

PANAVISE TILTS, TURNS, AND \ ■*«" ROTATES TO ANY POSITION. IT HOLDS YOUR WORK EXACTLY WHERE YOU WANT IT.

PRICE: s1449

DEALERS CALL FOR

PRICING

MEMORY MEMORY

2102LIPCLuw Power 450ns in lots of 25 $1.10 2102AL.-2L.ow Power 250ns in lots ot 25 $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/$65.00 $9.00

2716 16K 5 Volt Only EPROM $40.00

ELECTRONICS®

16723K Roscoe Blvd. Sepulveda CA 91343

Terms: Visa, MC, BAC, Check, Money Order, C.O.D. 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 to change without notice.

'SOCKET and CONNECTOR ... ... . ' . . . f . ., u Hfton _„.

prices basad on gold, not We will do our best to maintain prices thru Feb. 1980 OEM and Institutional

exceeding $376.00 per oz. phone orders welcome (213) 894-8171, (800) 423-5633 inquiries invited.

ORDER

1-800

except CA

(213)

Pectffi

WRAP POST

for .042 dia. holes (all boards on this page] T44/C pkg. 100 . . $ 2.34 T44/M pkg.

1000 $14.35

A-13 hand installing

tool $ 4.19

TOLL FREE

423-5633I

., AK., HI., CALL

894-8171

ORDER TOLL FREE 1-800-423-5633 ORDER TOLL FREE 1-800-423-5633

Circle 219 on inquiry card.

Computer Products

CHIP* 1*

Of*

MEMORY PRICES REDUCED !!!

sOsy

S7"EA*S

•our best selling memory 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

16K boundaries & protect via dip switches

Kits come with sockets for full 64K

Invisible refresh

MEM-16130K (16K KIT) $239.95

MEM-16130A (16K A&T) $289.95

MEM-32131K (32K KIT) $309.95

MEM-32131A (32K A&T) $359.95

MEM-48132K (48K KIT) $379.95

MEM-48132A (48K A&T) $429.95

MEM-64133K (64K KIT) $449.95

MEM-64133A (64K A&T) $499.95

S D SYSTEMS

PROM-100

VERSATILE EPROM PROGRAMMER

S-100 bus compatible (note: board height 7") Dip switch selects 2708, 2716, 2732, 2758, or 2516's 25 VDC programming pulse generated on board Programming time only 100 seconds for 16K bits Support-software listing provided in manual Program and erasure verification Software provides for reading of object file from CP/M and programming into EPROM

MEM-99520K (KIT) $175.95

MEM-99520A (A&T) $225.95

S D SYSTEMS

EXPANDOPROM

\EXPANDABLE TO 32K USING 2716 EPROMS

S-100 bus compatible, uses 2708 or 2716 EPROMs Dip switches allow selection of: each EPROM, 16K or 32K boundary, wait states

MEM-32220K (KIT) $149.95

. MEM-32220A (A&T) $199.95

GET THE INSIDE TRACK

JADE DOUBLE-D

DOUBLE DENSITY DISK CONTROLLER

Read/write single or double density, 8"or 5'/4"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 mill

IOD-1200K (DOUBLE-D KIT) $285.00

IOD-1200A (DOUBLE-D A&T) $349.00

IOD-1200O (MANUAL ONLY) $15.00

S D 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 51/4" drives controlled simultaneously

Operates with Z-80, 8080, and 8085 CPU's

Controls up to 4 drives

Vectored interrupt operation optional

IOD-1160K (KIT) $335.95

IOD-1169A (A&T) $385.95

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

IOD-1150K (KIT) $189.95

IOD-1150A (A&T) $239.95

NEW 2 OR 4 MHz REV. C BOARD

THE JADE BIG Z

Z-80 CPU BOARD WITH SERIAL I/O PORT 2 or 4 MHz switchable, on-board 2708,2716, or 2732 EPROM useable in SHADOW mode (full 64K RAM) Automatic MWRITE generation if no front panel On-board USART for sync or async RS232

CPU-30201K (KIT) $159.00

CPU-30201A (A&T) $209.00

S>U£

S D SYSTEMS

EXPANDORAM II

4 MHz RAM BOARD EXPANDABLE TO 2S6K

S-100 bus compatible, up to 4 MHz operation

Expandable memory from 16K 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-16631K (16K KIT) $295.95

MEM-16631A (16K A&T) $345.95

MEM-32632K (32K KIT) $369.95

MEM-32632A (32K A&T) $419.95

MEM-48632K (48K KIT) $444.95

MEM-48632A (48K A&T) $494.95

MEM-64632K (64K KIT) $519.95

MEM-64632A (64K A&T) $569.95

S D SYSTEMS

VDB-8024

80 X 24 I/O MAPPED VIDEO BOARD

80 character by 24 line display, 7X10 dot matrix Composite or seperate TTL video outputs On-board keyboard interface with power On-board Z-80 and 2K RAM Blink, underline, reverse, protect, up/down scroll Upper/lower case characters, 32 special characters Optional 128 user-programmable characters

IOV-1020K (KIT) $329.95

IOV-1020A (A&T) $389.95

S D SYSTEMS

SBC-100/200

2 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

CPC-30100K (2 MHz KIT) $249.95

CPC-30100A (2 MHz A&T) $299.95

CPC-30200K (4 MHz KIT) $289.95

CPC-30200A (4 MHz A&T) $339.95

250 BYTE February 1980

PRICES SLASHED FOR FEBRUARY !

CALL TOLL-FREE AND SAVE

800-421-5809 CONTINENTAL U.S. 800-262-1710 INSIDE CALIFORNIA

S D SYSTEMS

IZ-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 for 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

CPS-30010K (KIT) $279.95

CPS-30010A (A&T) $349.95

CP/M 2.0

Digital Research has done it again! This new release of their industry standard disk operating system is bound to be an even bigger hit than the original version. All of the fundamental file-size restrictions of release 1 have been eliminated, while maintaining full compatibility with the earlier versions. This new release can be field-configured by the user for a single mini-disk up through a multiple drive hard-disk system with 128 megabyte capacity. Field configuration can be accomplished 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

WERE PROUD OF OUR MOTHER I

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 PACKAGE PRICE

IROCKWELL AIM-65

\THE HEAD-START IN MICROCOMPUTERS

lKIM-1 compatible Ion-board printer IfuII ACSII keyboard

AIM-65 W/1K RAM..$375.00 JQp^SiiPJBjl AIM-65 w/4K RAM..$450.00iMM.—»■-- *ISf 8K BASIC ROM..$100.00 " POWER SUPPLY..$59.95/ CASE for AIM-65..$49.95_ | 4K Assembler/Edltor..$80.0<T

Special Package Price $599.00

4K AIM-65. 8K BASIC ROM, Power Supply, and Case.

JADE MEMORY EXPANSION KITS

FOR

TRS-80 APPLE EXIDY

Everything you need to add 16K of memory to your computer. Your kit comes neatly packaged with easy to follow instructions. In Just minutes your computer is ready to tackle more advanced software.

$75.00

AVAILABLE IN FEBRUARY

NEW JADE P/S I/O

PARALLEL/SERIAUINTERRUPT BOARD Z-80 SIO/PIO, 2 CTCs, expands to 2 SIOs, 4 CTCs 4 serial ports (async, sync, bisync, SDLC/HDLC) 2 parallel ports with full handshake Software baud rate generators, interval timers, counters, and generates 32 vectored interrupts Designed especially for MP/M multi-user multitasking operating systems. For use with Z-80 only

IOI-1045B (BARE BOARD) $45.00

IOI-1045K (KIT) $169.95

IOI-1045A (A&T) $224.95

MICROPROCESSORS

F8 $16.95

Z80 (2MHz) $10.95

Z80A (4MHz) $14.95

CDP1802CD $24.95

6502 $11.95

6800 $12.50

6802 $20.00

8008-1 $15.95

8035 $24.00

8035-8 $24.00

6080-A $10.00

B085 $23.00

TMS9900TL $49.95

8080A SUPPORT DEVICES

8212 $5.00

8214 $4.65

8216 $2.95

3224 (2MHl) $4.30

8226 $2.75

8228 $6.40

8238 $6.40

8243 $8.00

8251 $7.50

8253 $20.00

8255 $6.40

B257 $19.95

8259 $19.95

8275 $69.95

8279 $17.70

USRT

S2350 $10.95

UARTS

AY5-1013A $5.25

AY5-1014A $8.25

TR1602B $5.25

TMS6011 $5.95

IM6403 $9.00

BAUD RATE GENERATORS MC14411 $10.00

6800 PRODUCT

6821P $5.25

6828P $12.00

6834P $16.95

6850P $4.80

6852P $7.50

6860P $9.25

6862P $12.00

6875L $7.30

6880P $2.50

CHARACTER GENERATORS

2513 Upper $7.95

2513 Lower $6.75

2513 Upper (5 volt) ... 9.75 2513 Lower (5 volt) .. $13.00 MCM6571 up scan .. $13.00 MCM6571A down scan$10.95 PROMS

1702A $5.00

2708 $8.95

2716 $39.95

2716 (5v) $39.95

2758 (5v) $30.00

DYNAMIC RAMS 4116/416D 8 lor $74.95

2104/4096 $4.75

2107B-4 $3.95

TMS4027/4096 $4.75

STATIC RAMS

21L02 (450ns) $1.50

21L02 (250ns) $1.75

2101-1 $2.95

2111-1 $3.25

2112-1 $2.95

2114L (450ns) $5.75

2114L (300ns) $5.95

TMS4044 (450ns) $8.00

TMS4044 (300ns) $9.95

410D (200ns) $9.95

4200A (200ns) $9.95

Computer Products

4901 W ROSECRANS, HAWTHORNE, CA 90250 2)3-679-33)3

PLACE ORDERS TOLL FREE

800-262-1710 800-421-5809

INSIDE CALIFORNIA CONTINENTAL U.S.

WRITE FOR OUR FREE 1979 CATALOG FOR CUSTOMER SERVICE OR TECHNICAL INQUIRIES

CALL 213-679-3317 TERMS OF SALE: Cash, checks, money orders, and credit cards accepted. Minimum order $10.00. California residents add 6% sales tax. Minimum shipping and handling charge $2.50. Prices are for U.S. and Canadian delivery only and are subject to change without notice. For export prices and lation send tor a JADE INTERNATIONAL CATALOG.

INTEGRAL DATA SYSTEMS

THE PAPER TIGER

132 COLUMN DOT MATRIX PRINTER

Up to 198 CPS

1.75 to 9.5 inch adjustable

tractor and friction feed.

Parallel and serial

interface.

98 character ASCII set.

80 to 132 columns.

6 or 8 lines per inch.

Eight software selectable [j

character sizes.

110, 300, 600, or 1200 baud.

PRM-33440 $995.00

PRM-33441(with graphics & 2K buffer).. $1195.00

GUARANTEED PREMIUM QUALITY!

JADE DISKETTES

MAGNIFICENT MAGNETIC MEDIA I

5'/4" single sided, single density, box of 10

MMD-5110103 (SOFT SECTOR) $29.95

MMD-5111003 (10 SECTOR) $29.95

MMD-5111603 (16 SECTOR) $29.95

5'/4" 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 10

MMD-8220103 (SOFT SECTOR) $57.95

SPST DIP SWITCHES

hk»» / fr-r bb ##i

ttv I 1

PART NUMBER

SWD-103

SWD-104

SWD-105

SWD-106

SWD-107

SWD-108

SWD-109

SWD-110

NUMBER OF SWITCHES

s^v

3 4 5 6 7 8 9 10

$1.00 $1.05 $1.10 $1.15 $1.20 $1.25 $1.30 $1.35

PRICE $4^18"

$i*r

$1*88" $*i3tf $*rS4

S>ss

$*t38

TEXTOOL

ZIP* DIP II SOCKETS

2SEBGQS]

E=3

mrr

16 PIN ZIP* DIP II $5.50

24 PIN ZIP* DIP II $7.50

40 PIN ZIP* DIP II 10.25

• ZERO INSERTION PRESSURE

SPECIAL FEBRUARY PRICE I

NOVATION CAT

ACOUSTIC COUPLER/MODEM

$175.00

Let your computer talk to other computers ! Bell Systems 103 compatible^ 300 baud, answer or orginate IOM-S200A (SALE PRICED)..

. $175.00

Circle 220 on inquiry card.

BYTE February 1960 251

■t~/|aDMVNCED

VT b^COMPUTER

^\/TOODUCTS

FLOPPY DISK DRIVES

PERSCI Model 277 Dual ...119500

MPI B31-8W. 40 Iracks 279.00 WANGO/SIEMENS 5V Drive. 290.00

Shugarl SA400-5V 35 lracks.295.00 MPI B52 5'V Dual 395.00

Shugarl 800/801 R 8 495.00 WANGO/SIEMENS 282 Dual 514"

Siemens Shugarl Compatible 395.00

Model 120-BD 449.00

EXIDY SORCERER

$1099 W/16K $1249 W/32K $1449 W/48K

User programmable or use cartridges. Combines the desirable features of Hie PET. APPLE and TRS-80 into a complete expandable computer system.

** I/O expansion kit SI49.00

** Vista Exidy Dual Floppy Add-on S1 199.00

** New Word Processing Pac

S 250.00

♦ INCLUDES: Keyboard & enclosure 90 day Warranty MICROSOFT BASIC Video S Cassette Cable Complete Documentation #+ S100 Expansion

Module Add S299.00

*# Cassette recorder

Add S44.95

* # Sanyo 9" Monitor

Add S169.95

-i -« *.«■ «« SALE S100.00 OFF .. . and it's COLOR

"The Compucolor II"

. a personal colorgraphics system lor the modern computer man

+ Color Graphics 13" Color CRT

* Proven 8080A CPU System , i '

* 16K Extended Disk Basic 1^^ Tl 'I

* Up to 1 17' Key Keyboard ,: !

* Up to32K- RAM

* Minidisk Drive 51.2K Bytes/Side

Model 3 w/8K, 72 Key Keyboard. RS232 . 5$gf ...[ SI 595.00 Model 4 w/16K, 72 Key Keyboard. RS232 J^nn Isi895.00 Model 5 w/32K, 72 Key Keyboard. RS232 ncp ..-ls2195.00

Options:101 Key Keyboard Add S 150.00

1 1 7 Key Keyboard Add S225.00

Formatted Diskettes 2/S9.95

Programmed Diskettes S 19.95

Diskette Library Inc. Hangman. Othello. Math, Chess; Startrek. Blackjack, Cubic TicTacToe. Finance Vol. I, Finance Vol. II, Bonds and Securities. Assembler, Text Editor. Personal Data Base.S19.45 S29.00

ATARI 800 & 400

ATARI 800 $899-00 Includes:

Computer Console BASIC Language Cartridge Education System Master Cartridge BASIC Language Programming

Manual 800 Operator's Manual w/Notebook Alari 410 Program Recorder Guide to BASIC Programming

Cassette 8K RAM Module Power Supply TV Switch Box

ATARI 400 $499i00 Includes:

Computer Console BASIC Language Cartridge BASIC Language Programming

Manual 400 Operator's Manual w/Notebook Power Supply TV Switch Box

Z-80 based singleboard computer by SD Systems

* 1 K RAM + RS232 porl

* 4 channel counter/timer

Kit S239.00

Assembled S369.00

Cromemco Z80

:. Smglf Card Compi

$450.00

ROM Capacity- 8K Bytes local

address 0000 to 1FFF

ROM Type: Intel 2716 PROM o

RAM Capacity: IK BylSS UCOI Mdr./v. 2Q0Ulo23Ff RAM Type: 404S Static

RCA COSMAC VIP

NEW LOW PRICE $249.00

Assembled. Regular price S299.95

w/Sanyo 9" Monitor S169.95

252 BYTE February 1980

AEMVNCED"^™ COMPUTER PRODUCTS

Ul'll.lll.l

S-100 32K (uses 211

ASSEMBLED 450ns 599.00 250ns. 699 95 Bare Board 49 95

Board w/all parts

RAM 65 11 6K Static W/Memory

Management)

2 MHz $299.00 4 MHz S399.00

RM 16 (16K Static w/Bank Select)

2 MHz S249.00 4 MHz S329.00

(16K Assembled & Tested Using Low Power

2114's)

LOGOS ISK

ASSEMBLED 450 ns 149.95 250ns 169.95

KIT 450ns 125 95 250ns 149 95 Bare PC Board w/Dala S21.95 "Special Oiler" Buy 141 8K 450ns Kits S11 7 (

TRS-80 ADD-ON DISK

**:

VISTA V-80 MINIDISK 23°o More Storage Capacity - 40 Tracks ■10 t'ack patch free JW Double Density Expansion Module S239 00 2 Drive Cable Add S29.95 A D'lve Cable Add S39 95

(395.0o)

S-100 ADD-ON MINI-DISK

• VISTA V-200 Minifloppy System

* 204K Byle Capacity *■ Double Density Drive + CP/M & Basic "E" *■ Double Density Controller

* Case and Power Supply

*■ Assembled & Tested Ready to Pino, In

• EXIDY. HORIZON. SOL. etc. Compatible

S-100 ADD-ON DISK

SUBSYSTEM AmoooN

* VISTA V-1000 Floppy Disk fi699.0Cj) SuPsystem >L J

* (2) Shugait©" Disk. Drives —

* Case with Fan & Power Supply

* VISTA Floppy Disk Controller Card

* CP/M Disk Operating System

* Fully Factory Assembled S Tested

LOW-COST ADD-ON DISK SUBSYSTEM KIT

+ (2) 8" Drives + VISTA Floppy Controller Card

* Power Supply and Interface Cable

* CP/M Disk Operating System *■ Bo* of 10 Diskettes

IMS STATIC RAM BOARDS gr

* Memory Mapping * Low Power V*

* Phantom * Assembled & lested Recommended by Alphamicrosystems

250 ns. 450 ns.

8K Static 3209.00 S189.00

16K Static S449.00 S399.00

32K Sialic S799.00 S699.00

ANADEX PRINTER

Model DP-8000 compact, impact, parallel or serial. Sprocket feed, 80 cols, 84 lines/mm., bi-directional. New only S895.00

FLOPPY DISKETTES

&

+ 5'm" Minidiskettes • p^ o

Softsector, 10 Sector, 1 6 Sector v^Ov-^S S4 25 Each, 10/39.95 --- :'- '"

* 8" Standard Floppy Disks Soft Sector. Hard Sector S450Each, 10/41.95 •Add 4,95 for 10 Pack in Deluxe Disk Holder

MOTOROLA EXORC1SER COMPATIBLE

9600 MPU Module w/6802 CPU S495.00

9601 16 Slot Mother Board 175.00

9602 Card Cane 11 9" Relma Rack Mount) .. 75.00

9603 8 Slot Mother Board 100.00

9604 Switchmode System Power Supply . 250.00

96 1 0 Utility Prototyping Board 36.00

9616 Quad 8K Eprom Module ***

9620 16 Channel Parallel I/O Module. .295.00 9622 Senal/Parallel I/O Combo '"

9626 8K Sialic RAM Module 295.00

9627 1RK Static 450ns 495.00

9630 Card Extender 68.00

9640 Multiple Programmable Timer

(24 Timers] 395.00

9650 8 Channel Duplex Serial I/O 395.00

96103 32/32 I/O Module 275.00

96702 32 Point Reed Relay Module 6000 BARE BOARDS

9620-0 S45.00 9603-0

9626-0 .. 45.00 9600 ......

9650-0 45.00 96103

9601-0 50.00 96702 ....

Also AM! EVK System in Stock

350.00

55.00 55.00 55.00

* 16K with Jumpers & Instructions tor either Level I or Level II $69.95

* 16K for Apple II Upgrade S69.95

* Special: TRS80 Schematic S 4,95

* Expansion Interface Schematic .. S 4.95

* Expansion Interface Connector... 7.95

EXPANDORAM II MEMORY KITS

* Bank Selectable * Uses 4116 200 ns.

* Write Protect * Power 8VDC, ±16VDC + Phantom * Up to 4 MHz

Expando64 Kit (4 1 161

16K S248.95 48K S439.00

32K S358.00 64K S519.00

FROM INTEGRAL DATA SYSTEMS MODEL 440"THE PAPER

.5" adjustable tractor TIGER feed, parallel & serial I/O, 132 columns, software selectable character size.

110,300,600, 1200 baud, to 1 98 cps.. $995.00 Graphics option w/2K buffer add £ 1 99.00

TASA touch activated solid state KEYBOARD

• Full 128 position 8-bit ASCII

3 color code. 55 positions Immune to static charge

• Low power

Only 89.95 Optional stand 1 5.00

UV "Epro

Pint.

Eraser

Model UVS-11E $69.95

Holds 4 E prom's at a time

Backed by 45 years

experience

Model S-52T... S265.00

sional Indusi'inl Model

TARBELL FLOPPY INTERFACE

* 280/8080 S IO0 Compatible * Uses CPM Assembled for Shugarl SALE S259.95

Assembled Other Drives S26S 95

Kit S17995

Bare Board S39.95 (Doc AddSIOOO)

■ cpm And S70 0Q Documentation And s?ooo

Vista Double Oi

SD Versa Floppy Kit II

SD Versa Floppy Assembled 1

Tarbel Cassette I/O Kit ..

Sale* 1771-01 Floppy Chip

VISTA Floppy Controller 8" (S

Controller Assem

-t Cornp I

?.'.)9 00 S299.00 S389.00 SI 15 00 S27 95 S259.95

NEW CENTRONICS 730 PRINTER

^^r----~—~> Uses any paper roll, fanfold, s WOW X single sheets, 96 character 13945.00/ ASCII, 7 x 7 clot matrix, 50 V-.l^^-^ CPS, RS232 or parallel I/O

Z-80/Z-80A/8080 CPU BOARD

• On board 2708 * 2708 included (450ns.)

* Power on jump * completely socketed

• Z-80 Assembled and Tested S1 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 S69.95 NOW S52.95

SIEMEN'S FLOPPY SALE')

• Special buy while supply lasts.

• 8" Drive with DoubleDensity

• 90 Day Warranty $449.00

sk Holder I

ACOUSTIC MODEM

NOVATION CAT™

0-300 Baud

Bell 103

Answer, Originate S189.00

ACOUSTIC COUPLER SPECIAL

AJ MODEL A30 SPECIAL PURCHASE OF SURPLUS UNITS AVAILABILITY LIMITED S29.95

DATA BOOKS • COMPUTER BOOKS

.9 95 ln.lt?" MCS :'0 M,in

3 95 Inlel MCS 40 Man

.195 AMDgnm-JA Man.

395 AMD 5ci'.rV!l-y Da!

395 AMI MOyi.SI D.-il

395 Gl MOS/t.SI D;ira

NSC 7TL Dala

NSC Linear Arjr NSC CMOS NSC Memory

Intel Datafcrook .. 4 35

Intel MCS S5 Manual 7 50

SALE ■ OSBORNE BOOKS

Vol III Same Real Support Device? w/Bmder

SALE • DILITHIUM COMPUTER BOOKS •

Understanding Compute's BOUOMierOCOmputer E«wninen!s

Beginning BASIC

Bcciinner-.. Gi05SCi-y £ Guide

Peanut Butler j. Jelly Gu.de !o Computers

6080 M,i-r-,-,e Language P--jamming

me Com:

T3-J*. I ■■Hit

T-9*

THE FIRST TO OFFER PRIME PRODUCTS TO THE HOBBYIST AT FAIR PRICES NOW LOWERS PRICES EVEN FURTHER!

■■ "l"OV©n \j|U3IIVy Factory tested products only, no re-tests or fallouts. Guaranteed money back. We stand behind our products.

1980 CATALOG AVAILABLE SOON.

Send $1.00 to reserve your copy of the most complete catalog of computer products. A must for the serious computer user. MICROPROCESSORS STATIC RAM HEADQUARTERS SOCKETS

12 95 19 95 ■19 95 I" 95

13 95 24.95 19 95

SUPPORT DEVICES

17.95 49 95 16.95 1 75

5.95 39 95 895

MCG84S8 821 SCD IN I-.:.? SCD 25. 824 CD 32 ■ 652 CD 5 Drt

854 Uan

855 CD i O 857 CD I O

*>520 Pia

DYNAMIC RAMS

■ :()ly) -IK .1091= .IK 2104 4K 4027 AH.

52 70 -195 5280 -195 5290 1245

PROMS

6605 6604 6002

99 00 34 95 29 95 29 9.'!

SALE 9223 32 «

82S11

, 512 x

(TS)

23 32x

82S126 256 <4

32S129 256 x 4 (TS) .....

825130 512 <4(OCI

NSC DM7578 32 x B ..

8ZS23

825131 . V 87S137 1

CHARACTER GEN

SK»13"U01 |5Vi unner

2513-OOSI5VI Lower i

2513-ADM3 l5Vll.iw.er 1

MCM6571 II

MCM6571A 11

MCM657J 1,

MCM6575 I.

UARTS/USRTS

SALE TR1472B 9.95

BAUD RATE GEN

KEYBOARD ENCODERS

HD0165 9

74C922 g

74C923 9

A/D CONVERTERS

i.lOaLf- ■■MCBLci;i PACOi A i

1-24 25-99 100

21L02 450n<. 1 30 1 25 115

21L-02 250ns i 59 I 55 I 45

21 11 3 75 3.65 3 55

21 12-1 2 95 2 65 2 65

2101-t 29u 2 70 2 55

21 ML-250ns 12.95 10.95 995

21 14L-3O0;i'. 395 7 95 6 45

2114L-450ns. 7 50 6 75 4.75

4044/4041 3O0ns 9 95 8 75 7 95

TEXTOOL ZERO

INSERTION FORCE

EMM4402 7 95 7 25 6 25

SOCKETS

EMM480-1 12 50 11 50 9 95

' ' ■' i ( E f 95 7 95 7 25

uOC!4'0|430Gi '095 '025 925

AMDS 140-41 '096 '025 9 25

AWD91 SO 11 '295 " 95 102 =

CONNECTORS

DB25PIRS232I 3 25

DS25S Female 3 75

PS1?ft 93425 >*?> "■-' 795 7 35 1 2S

214 7 Low Power 4K Static 14.95e;i

50/100 S-100 Conner.tor <n/W A 25

CHARGE COUPLED DEVICES

CTS DIPSWITCHES

CTS20IJ-4 51 ■■■ : IS.Dt B SI 9!

CIS30&5 SI 7:- CTS20I 9 S1 ••

$1 8.95 each (reg. 43.OO)

CT8306-7 Si 75

CRYSTALS

Microprocessor Timebases TV Came

NAKED PC BOARD SALE

Frequency Price Frequency Price

1-80 CPU (llhiir,ii S34 95 3090ACPU 34 95

32KS!iiliC RAMI2114I 49 95

C,l-.'..-!!fl'C),T.1rb..1l1 2995

DISPLAYS/OPTO/LED'S

* 7 SEGMENT * CALC * CLOCKS •

DL 704 (IX), DL '707 ICA) 300* Red 99

FND357 ICO 357" Rod . 99

1 MH '.0O.'5O.j ,CC) hOO" Red 99

WAVEFORM GENERATORS

k r.-rjzivji.

15.95

MA1002ALEO 13 h, Clcck Module ,095

* HEX DISPLAYS * ENCODED DISPLAYS * HP 5082-7340 Red Hewdectmal 15.95

HI1 :,nn::-,':i:X) n.-d NvmerK:

TIL J05

TIL 306 Nyn,e,,c w/LoglC

TIL 308 Number w/Logic..

TIL 309 Numba, W/LOgta.

TIL 311 Hexadecimal

695

8.95 13 95

FLOPPY DISK I/O

TV INTERFACES

SPECIAL PURCHASE (while supply lasts)

21L02-4(450ns.). ...99 21LO2-2(250ns.)... 1.15 TMS 4060 (pullouts)

1.95

P8251 Intel 4.95

FCM 7001 Clock... 5.50 MM 5311 Clock... 4.50 MM5314Clock...3.95

MM 2114N 4.49

8085 17.95

MK 3870 (programmed)

1.50

AM 9CB0(4K RAM)

3.95

27S08 (32 x 8) ... 1.95 75492 .75 8080A CPU .... 2/9.95 271 6 Eprom... 2/49.95 76477 Sound... 2/7.50 16K Rams 200 ns. 100/6.95 ea.

NOTICE: WE DOCUSTOM PROM PROGRAMMING

COMPUTER SPECIALS

LIST

SALE

Apple II Plus W/16K 1195.

990.

IPSI 1620Diable RQ3295.

2 (-.95

PET 2001-16N 995.

895

Anade< DP 8000 995.

895

Exicly Sorcerer w/SK 89-5.

795.

Centronics Micro P-1 595.

895

Compucolor II W/8K 1495.

1395

Centronics Micro S-1 595.

525

CromemcoSys in 6585

5475.

Soroc 10 120 995.

795

Horizon I W/32K 1849.

1559

Telt-lyprj Model 43 1349.

1150

TEI Pi;>0S? W/32K

HiFlot Plotlc>r 1085.

899

dual floppy 8 CRT

HiFlot Digitize! 795.

735

i avail i 4y95.

2495

Mertubell 895.

Pascal Microengine 2995.

2395.

SOL 20

1095

* LED'« * OPTOISOLATERS .

LEDS Red. Yellow, Oreen 185

MCT 2 Photo XSTR HFE 250. 30V 4N25 Ptiolo XSTP HFE 250. 30V 4N33 Pholo Darlmglon ..

MONTHLY IC SPECIALS

> DS3625

i 75322

995 10147 ECL Ram

l n LF356HBiFei 3.

1 00 MCr.M.1505

2 35 ■■-JSS9 3, 1 99 74107N 6. i 33 ^452M 8.

TV CHIPS/SOUND

AY38500-1 6 Games BW = AY38515 Color Convertt-r .-.V5ri(.:.0:t-1 H(i;u)iiii;e Game

a> 38605-1 Warfare Same

AY3B606-1 Wippout Game AY3S607-1 S»oc)tiJ,fjGallf/rV AY389l0Giriuni Cnckt?' SOuf Gcnrjraloi

SN76477T1 Sound Qenera.cu MMS380/21 TV Synch Sen

MM53ii;t F-'n-sCiilfir LM1889 RP Modulator MM571000 NSC Color TV

MM57104 Clock Gen RF WodutatW w/Auflio

All Shipments FCM or UPS O'Uer Lincliv SI0000 arid 5'V unnr-hnu ,im

postage Orders ovor sioooo art 2 5% Handling A postage Mastei

COD act.-im-il -mi25% aej)05.!.Cali

8 95

9 50 9 50

9.95 3.95 3.95

3 75 B.95

Orde'S add 8% "lanoling All Ddms lactory tested guara Add) 35 cents lor Data Retail pricing may very Iron Order Pnr.nii All pnemg sub Changti witrioul nonce

Fore

P. O. BOX 17329 Irvine, California 92713 Phone (714) 558-8813 K5T«iR!™£J&.

For International Orders: 1401 S. Borchard, Santa Ana, CA 92705. (714) 953-0604. TWX: 910-595-1565 Santa Ana, CA 92705

Circle 221 on inquiry card.

BYTE February 1980 253

The Supermarket for TRS-80 Add-on Components

*

(and other computers, too)

The VISTA V-80 Disk Drive System

• 23%more storage capacity than TRS-80

• 120 day warranty

• 40 track patch at NO CHARGE

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 density modification to your current Radio Shack interface (lets you format diskettes in either single or double density].

• Increases storage capacity up to 204K bytes (on single 40 track drive].

• Includes all hardware

§239.00 software

The VISTA Model II

• Provides one, two or three drives.

• Adds up to 1.5 million bytes of on-line storage.

• 120 day warranty

• Does everything Radio Shack's expansion system 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... $895.00

9x7 dot matrix

80 column — .

VISTA

Printer... $745.00 5x7 dot matrix80 column

Cables $27.50 each

Add On Drives

MPI B51 40 Track. Double

Density-204K $275.00

MPI B52 Dual Head. Double

Density-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) Certified 40 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 Exldy.

• Completely packaged system, tested and ready to plug in, includes: power supply, two 40 track drives, case, controller, all cabling and total CPM documentation.

• Storage capacity from 400K to 1.2 meg. ^

• System software-VISTA CP/M Disk Operating System and BASIC-E Compiler J recorded on 5-1/4" diskettes. I

Price: Starting as low as $1199.00

^^^^^P CALL TOLL-FREE 800-854-8017

V

•TRS-80 is a registered trademark of Radio Shack

The Vista Computer Company 1401 Borchard Street "Santa Ana, California 92705*714/953-0523

254 BYTE February 1980

Circle 222 on inquiry card.

Unclassified Ads

FOR SALE: No longer allowed access to timesharing system, so I must sell. I have a complete working terminal featuring a XITEX SCT-100 terminal board. ASCII

keyboard, modem, power supply, RF modulator, and all cables. Reasonable offers start at S250. I'll pay shipping. Scott Swanson. RR #2 POB 247. Blue Grass IA 52726. (319) 381-2036.

FOR SALE: Three Heath H11 (or DEC PDP-11/03) static memory boards 4 K by 16. Practically new. $200 each or S575 for all three. M Lowenstein. 79 Larkspur Rd, Stamford CT 06903. (203) 853-7856.

FOR SALE: Magazine sets: BYTE issue #1 to issue #16, Creative Computing volume 1 #4 to volume 2 #6, Kilobaud issue #1 to issue #12, Microtrek volume 1 #1 to volume 1 #2, and Personal Computing volume 1 #1 lo volume 1 #6. Excellent condition. Please quote offer. F J Scavo, 1811 Court St. Syracuse NY 13208.

FOR SALE: Three Digital Group 8 K memory boards. 450 ns. Very reliable. $140 each. M S Judy, 6401 Hamilton Av, Cincinnati OH 45224, (513) 542-2787.

FOR SALE: Heathkit computer system. Includes H9 video terminal. H8 computer with 8 K memory, serial

input/output (I/O) cassette interface, all manuals and cables. Less than one-year-old. $900 for entire system. B Helsel. POB 35. Cudahy Wl 53110.

FOR SALE: Heathkit factory assembled and working H11 system (equivalent to LSI/PDP-11), with full memory and interfaces plus H10 paper-tape reader punch. Total cost over $3400. best reasonable offer accepted. Mr Block. POB 231, Hallandale FL 33009. (305) 456-6209.

FOR SALE: TRS-80 Level 1 microcomputer. Only seven months old. Voice synthesizer and manual included. Eighteen popular software and game programs also included. Computer in great condition. Keyboard, cassette recorder, and video display are also included. Demonstration tape included with voice synthesizer. $1211. Rob Wiley. 1009 S Sterling Av. Tampa FL 33609.

FOR SALE: ELF II system with two 4 K memory boards (factory tested), Giant Board (factory tested), ASCII keyboard. AP-1 5 A power supply (±8 V DC, 20 V AC/PPl. RF modulator. Tiny BASIC cassette, complete

documentation. Main board may have one or more defective integrated circuits. Will sell for $275. R C Saunders. 8902 River Rd, Richmond VA 23229, (804) 740-8071.

WANTED: TRS-80 business software disks. I want to purchase programs for business applications at an affordable cost. They can also be in TRS-CPM version or TRSMicrosoft-FORTRAN. Douglas Gilson, Rua Sambaiba 516 Leblon, Rio de Janeiro, BRAZIL.

FOR SALE: Digital Group system. 30 K random access memory, 4 K erasable-programmable read-only memory with custom monitor/debugger, dual Phi-Decks, CDC floppy. Sylvania 12-inch video display, custom front panel, paper-tape reader, interfaces for audio cassette, Tally printer, and programmer; $2200. Optional elecironic pinball machine; $400. Bought a larger system. J Kalafatas. 483 Park St, N Reading MA 01864, (617) 275-1800 ext 446 days.

WANTED: Information on Electronics Information Services (EIS) Model #ET-39 Telewriter. Mike Middleton, 1713 W Eva, Phoenix AZ 85021.

Unclassified Policy

Readers who are soliciting or giving advice, or -who have equipment to buy, sell or swap should send in a clearly typed notice to that effect. To be considered for publication, an advertisement must be clearly noncommercial, typed double spaced on plain white paper, contain 75 words or less, and include complete name and address information.

These notices are free of charge and will be pritited one time only on a space available basis. Notices can be accepted from indroiduals or bona fide computer users clubs only. We can engage in no correspondence on these and 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 tnagazine.

FOR SALE: RCA Cosmac VIP assembled with video modulator. All in good working condition. All documentation. $160. Philip Best, 19 Brookside Ln, Mansfield Center CT 06250, (203) 429-5633.

FOR SALE: Centronics Micro Printer, RS-232, electrographic prinling, 4.6 inches wide: 20,40.80 characters per line; with twenty rolls of paper, $350 or offer. C Looney, 3406 Notre Dame St, Hyattsville MD 20783.

FOR SALE: Electronic Systems Apple II serial input/output (I/O). Assembled and tested. RS-232 input and output; up to 30,000 bits per second (bps). Plugs into Apple. Software routine included. $45. Bill Carlquist, 6253 Hollywood Blvd Suite 202, Hollywood CA 90028, (213) 461-4643.

TRS-80 USERS: Tiny-c and Assembler programming bulletin, Send SASE for inlormation. Rob Varty, 2193 Haygate Cr, Mississauga Ontario, CANADA L5K 1L7.

FOR SALE: Four printers with keyboards ($395 each). reconditioned Singer, dot-matrix impact, 80-character ASCII, 110/300 bps. asynchronous, RS-232 interface, friction or pin feed. M Osedo. 1367 Nanawale PI. Kailua HI 96734.

FOR SALE:TI 751 Baudot RO thermal printer. New printhead, manuals, not working; $150. RCA Cosmac-based video game as sold by Radio Shack; $50. Ralph Droms, Whitmore Lab. University Park PA 16802.

FOR SALE: Sell or trade Heath H8 mainframe, H8-1 4 K memory. H8-2 parallel input/output (I/O), H8-5 serial and cassette I/O. Godbout Econoram V! 12 K memory, and system software. Want $750 or OSI 1 P with 12 K. C2-4P with 8 K, or C2-8P with 4 K. Also have Digital Group TVC-64 for $100 and Radio Shack ASCII keyboard for $25. Robert Howarth Jr. RFD #1 POB 36, Lisbon NH 03585, (603) 838-6469.

FOR SALE: Line printer. Tally T-2200, 200 lines per minute. 132 columns. 5 by 7 matrix, up to six copies, adjustable tractors, 6/8 Ipi. 8-channel VFU. parallel interface. Cost $5000. asking $1600. Also available: warranty, service contract, other interfaces. John Marshall, POB 242. Renton WA 98055, (206) 226-0981.

FOR SALE: Poly 88 system. 32 K programmable memory, 3 K erasable read-only memory, 16 by 64 video with graphics and hardware scroll, keyboard, real-time clock, serial port, high-speed cassette. 9 inch monitor, documentation, and software: $1700 Canadian. North Star FPB; $275 Cdn. input/output (I/O) board with 2708 programmer, three parallel ports, two digital-to-analog (D/A) converters, 16-channel analog-to-digital (A/D) converter, sockets for 8 K programmable memory; $100 Cdn. Michael Dunn, 45 Livingston Rd #501, West Hill Ontario, CANADA M1E 1K8, (416) 266-1635.

FOR SALE: Digital Group four-board system with 10 K random access memory, four Pl/Os, video and cassette interface, large motherboard, and all documentation. Includes power supplies (5 V at 12 A, 12 V and 5 V at 1 A) and ASCII keyboard. Bought for $1150, will sell for $750 or best offer. Marvin Jones. 2600 NW 30. Oklahoma City OK 73112.

FOR SALE: SOL-20 in original box complete with monitor and cassette recorder; $1495. 8 K randomaccess-memory board; $100. GPM programmable-readonly-memory board; $60. Uses 2708 programmable readonly memories. Mountain Hardware 100,000 day clock; $100. Bob Haworth. POB 92, Boring OR 97009. (503) 663-6206.

FOR SALE: Teletype ASR33 terminal with paper-tape

reader/punch. Bell modem, touch-tone dialer, card autodialer, speaker with volume control, manual modem control buttons, and cables; recently reconditioned. $425 plus shipping. Mike Dearing, Rt 3, Spring Green Wl 53588. (608) 588-2991.

FOR SALE: Friden Flexowriter Model SPD. Includes parallel interface, but circuit needs minor work. Relays have been stripped, but will be included in the package. Friden schematics included. $100. John Kane, 2193 Charles Dr. Stevensville Ml 49127. (616) 429-8353.

WANTED: Any or all copies of Processor Technology's ACCESS newsletter. Peter Wayner. 37 Grandview Dr, Latham NY 12110.

FOR SALE: SwTPC 6800 computer system assembled. Includes: MP-68 processor, 8 K random access memory, MP-S. MP-L, AC-30, CT-1024, two Superscope C-101A cassefte decks. 4 K and 8 K BASIC tapes, Motorola K9TS-460Q video monitor/TV, Expandor Model 123P Black Box printer, custom walnut, leather, and acrylic case, complete system documentation. Asking $1950 plus shipping. R H Gay. 48 Maine St, Brunswick ME 04011, (207) 725-5835.

FOR SALE: Heathkit IG-102 signal generator 100 KC to 110 MC, $60 or best offer. Bell and Howell O-Scope single trace with Heathkit probes, $150 or best offer. Heathkit how to use programs for signal generator and VTVM, $30 each or best offer. Full documentation with above. Brian Hummert. 96 Hollywood Dr, Middletown PA 17057, (717) 939-7646 Mon-Wed 5:00-9:00 ET.

FOR SALE: Four Phi-Decks dress cabinets and Digital Group controller. Asking $700. Peter Bornstetn, 120

Ocean Pky, Brooklyn NY 11218, (212) 438-0949.

WANTED: Early issues of BYTE up to September 1976

Please send invoice (needed for Exchange Control I stating price. R L Bissessar, 52 Joyeau St, Curepe Trinidad, TRINIDAD AND TOBAGO, West Indies.

FOR SALE: Very large personal book collection. Subjects include electronics (engineering and technical levels), microcomputers, reference books, college texts, self-study courses, aviation, etc. Send 25c and SASE for complete listing. Also for sale, all new parts and chassis for unregulated power supply. +5 V at 25 A, -5 V at 3 A, +/-12 V at 3 A. Worth over $60. You pay $25 plus shipping. William Blair. POB 81042. DMAFB AZ 85707.

SWAP: OSI Challenger II owner willing to swap programs and information. Have a variety of programs from W1 Computer Games. 24 Tested. Ready-To-Run Programs In Basic, etc. Most 8 K but some will run in 4 K. (I have Assembler and Extender Monitor so I can run and to some extent modify machine-language programs.) Barry L Beal. RFD #1 POB 160, Machias ME 04654.

WANTED: Computerized options markets (C B O E. etc) and their underlying stocks are my interest, including multiple regression analysis, simulation, trading systems development, and computer interface with a securities quotation machine. I would like to correspond with those interested in trading ideas, programs, data bases, etc. J Spillane, Rd 1 POB 138, Sicklerville NJ 08081.

February 1980 © BYTE Publications Inc 255

tiesden Service

To get further information on the products advertiser! in BYTE, fill out the reader service card with your name and address. Then circle the appropriate numbers for the advertisers you select from the list. Add a 15-cent stamp to the card, then drop it in the mail. Not only do you gain information, hut our advertisers are encouraged to use the marketplace provided by BYTE. This helps us bring you a bigger BYTE. 'Correspond directly with company.

Inquiry No.

Page No.

Inquiry No.

Page No.

Inquiry No.

Page No.

Inquiry No.

Page No.

68 Aardvark Software 111

237 A B Computers 219

61 Ackerman Digital Systems 100

221 Advanced Computer Prod 252, 253

208 All Electronics Corp 243

231 American Square Computers 226

199 Apparat 235

9 Apple Computer 19

114 Applied Computer Systems 164

200 ASAP Computer Products 236 166 ATV Research 225

153 Automated Simulations 194

156 Avionic Enterprises (A.E.I.) 197

146 Badge-A-Minlt 189 14 base 2, inc 27

172 John Bell 225

185 Beta Business Systems 229

' Beta Computer Devices 183

• Bits, Inc 136, 179

* BNR 109

163 BYTE Books 209, 210, 211

113 Byte Shop East 164

• BYTE WATS 197

144 C & S Electronics Mart 189

204 California Digital 239

75 Central Data 123

13 Century Data 25

109 Chrislin Industries 158

234 Compas Microsystems 190

16 Compucolor Corp 29

202 CompuMart 237

95 CompuMax 145

49 CompuServe 79

195 Computer City 233

142 Computer Devices 187

54 Computer Distributors 87

* The Computer Factory 149 132 Computer Furniture & Ace 180

' Computer Headware 16

55 Computer Mart of NJ 88 212 Computer Service Ctr. 243

108 Computer ServSysNtwrk (CSSN) 157

175 Computer Specialties 226

136 Computex 182

147 Corporate Computer Sciences 189 26 Corvus Systems 47

138 Cover Craft 183

1 Cromemco 1, 2

52 Cybernetic Micro Systems 84

140 Cybernetics Inc 187

182 DATABANK 229

134 Data Discount Center 181

44 DATASPEED 67

165 Data Trans 224

31 Delta Products 55

90 DG Electronics 138

126 Digital Engineering 177

58 Digital Equipment Corp (DEC) 91

117 Digital Pathways 167

191 Digital Research: Computers 231

80 Digital Research Corp (CA) 130

143

Edmund Scientific 188

•

206

Electrolabs 240

168

206

Electrolabs 241

216

206

Electrolabs 242

53

57

Electronic Control Technology 90

111

103

Electronics Book Club 151

21

164

Electronic Systems 222, 223, 224

56

188

Electronic Technicians 229

155

87

Escon 135

157

209

Evergreen 243

66

73

Exidy 118, 119

19

215

FAIRCOM 243

84

201

Fordham Radio Supply 236

196

184

Frederick Computer Products 229

119

173

Gimix 225

124

122

Godbout Electronics 173

162

224

Graham Dorian CI 11

32

106

H & E Computronics 155

63

161

Hayden Book Company 208

160

8

Heath Company 17

59

45

Heuristics 68

76

189

Hobby World 230

*

232

Houston Instruments 81

77

233

Houston Instrument 81

78

65

Hughes Aircraft Co (Radar Sys) 107

120

145

IBC 189

300

110

Industrial Micro Systems 159

186

174

Infinite Inc. 225

12

25

Infosoft Systems Inc 45

107

88

Integrand 135

79

230

Interface Inc 226

225

92

International Data Systems 141

27

98

International Elec Equip Corp 147

127

22

Intertec Data Systems 41

159

94

Intertec Data Systems 143

123

3

Ithaca Intersystems 9

6

Ithaca Intersystems 14

41

220

Jade Company 250, 251

82

217

Jameco 244, 245

93

218

Jim- Pak 246, 247

229

*

Lifeboat Associates 83, 137,177

203

214

Macrotronics 243

158

54

MAR-COMP 87

141

67

Marketline 110

62

Maxell Data Products 101

18

*

McGraw-Hill Book Company 97

33

115

Measurement Sys & Controls 165

34

210

Measurement Sys & Controls 243

35

180

Merrimack Systems 229

36

129

MICAH 179

37

72

Mlcroamerica 115

38

150

Micro Applications Group 191

39

192

Micro Business World 232

40

198

Microcomputer Technology Inc 235

28

43

MicroDaSys 65

•

24

Micro Data Base Systems 43

152

*

Micro Diversions 5

51

139

Mlcromail 184

7

101

Micro Management Systems 148

219

112

Micro Mikes 163

69

•

Micro Mint 94

133

128

Micro Music 178

177

Micro Pro International 30, 31

Microsette 225

Microsette 243

Microsoft 85

Microsoft (Consumer Prod Div) 161

Micro Source 39

Microtek 89

Microware Assoc. 197

Microware Midwest 199

The Micro Works 108

Micro World 37

Midwest Computer Peripherals 133

Mlkos 234

Mini Computer Suppliers 168

Mini Micro Mart 175

Mini Micro Mart 208

Morrow/Thinker Toys 57

Mountain Hardware 103

Mountain Hardware 207

mpi 93

MT MicroSYSTEMS 125

Multi Business Comp Systems 229

NEECO 126

NEECO 127

Netronics 169

Netronics 169

Northwest Computer Services 229

North Star 23

Novation 156

NRI Schools 129

Ohio Scientific Instrument CIV

Ohio Scientific Instrument 49

OK Machine and Tool 177

Oliver Advanced Engineering 199

OmniTronlcs 174

onComputing 33

Oregon Software 63

Osborne/McGraw-Hill 132

Owens Associates 142

Pacific Exchanges 226

Page Digital 238

PAIA 199

Pan Am Electronics (A Radio Shack

Auth. Sales Ctr.) 187

Per Com Data 35

Per Com Data 59

Per Com Data 60

Per Com Data 60

Per Com Data 60

Per Com Data 61

Per Com Data 61

Per Com Data 61

Per Com Data 61

Personal Software 51

Phase One Systems 99

Pickles & Trout 191

Power One 82

Priority One 15

Priority One 248, 249

Program Design Inc 112

Programmers Software Exch 181

Quest 227

118 R & K Enterprises 168

71 RACET Computes 114

* Rainbow Computing Inc 204

* RBB 144

91 RCA Solid State 139

81 RCA Solid State 131

171 RCV Consultants 225

193 RNB Enterprises 232

194 RNB Enterprises 232 105 S-100 154

130 Sara Tech 179

* SAT-TRAK International 225 183 S C Digital 229

85 SCDP135

104 Scelbi 152, 153

10 SciTronics 20

60 Seattle Computer Products 95

* Shugart 6, 7

151 Sigma International 191

116 Small Business Computer App

166

228 Ed Smith's Software Works 199

29 Softagon Inc 52

227 Softside 170

137 Software Dev & Training 183

121 The Software Exchange 171

170 The Software Farm 225

83 Software Tech for Computers (STC) 133

20 The Soft Warehouse 38

154 The Software Works 197

178 Solid State Sales 228

211 Sorrento Valley Associates 243

223 Southwest Tech Products Corp CM

4 SSM11 23 SSM 42

100 SubLOGIC 148

74 Summagraphics 121

190 Sunny International 230

15 Supersoft 28

48 Sybex 77

46 Synchro Sound 71

86 Synergetic Computer Products 135 70 Tarbell Electronics 113

47 Technical Sys Consultants (TSC) 75

* Tec-Mar 221

5 Telecomputing Corp of Am 12, 13 64 Terak 104, 105

99 3 G Company Inc 147

* Robert Tinney Graphics 96 42 Tiny C 64

97 TransNet 146

102 US Robotics 150

181 Vantage Data Products 229

11 Verbatim 21

222 Vista Computer Company 254

179 VR Data 228 197 Wameco 234

149 Whitesmith's Ltd 190

213 Wintek 243

167 Worldwide Electronics 225

96 Zg Systems 146

BOMB — BYTE's Ongoing Monitor Box

Article # Page Article

1

18

2

32

3

58

72

92

106

7

116

8

128

9

176

10

192

11

202

A First look at Graphic Theory Applications

A Computer-Controlled Wood Stove

Solving Problems Involving Variable Terrain, Part 1:

A General Algorithm

A Computer-Controlled Light Dimmer, Part 2:

Implementation

Implementing Dynamic Data Structures

With BASIC Files

A Fast, Multibyte Binary to Binary-Coded-Decimal

Conversion Routine

A Quad Terminal Interface

Comparison of Some High-Level Languages

BASIC Formatted Output

A Financial Analysis Program

Another Plotter to Toy With, Revisited:

Design and Construction Details

Author

Ashbrook and Zinn

Clarcia

Jones

Gibson

Carter

McQuade

Alpert Morris Roch Lehman

Newcomb

Ciarcia - Highlight of November Games

It was a close race, but Steve Ciarcia won by a nose in the last lap of the November BOMB for his article "The Intel 8086," (page 14). But so close behind were Macdonald and Gursel with "Solving Soma Cube and Polyomino Puzzles," (page 26) that the judges decided to award first place to both teams. Amazingly enough, the same close race was run for second place which will be awarded both to Gary S Sivak for "A Special Spacecraft Simulator" (page 104) and "Alpha-Beta Pruning" by Dr Maurer, (page 84). Standard deviations for all four articles were between 1.12 and 1.10.■

256 February 1980 © BYTE Publications Inc

1

Gpehsmdcpien's Integrated, Do Line Ppcgpams Ape Fast, Efficient, And Easy Tc Use.

Rely on Graham-Dorian, a full-line computer software manufacturer, for sophisticated programs — the most detailed on the market today. They're ready to go to work immediately or to be tailored for even more specific needs.

On-line capabilities enable you to make a single entry and update all affected files. An inquiry into a file at any time provides up-to-date information — no batching or sorting of input data.

The programs are easy to use. Messages on the video display guide you each step of the way. Programs make use of indexed sequential and chained files for fast and convenient retrieval of data with efficient use of disk space.

Order on standard eight-inch disk or various mini-floppy formats. Each program contains a free user's manual and hard copy source listing.

• Accounts Receivable— Records invoices, prepares statements and trial balance reports, etc. Automatically reports aging of accounts in periods of 30, 60, and 90 days, with each item listed separately.

• Accounts Payable — Vendor lookup and change, entering vendor invoices, writing checks (many options), cash flow analysis, accounts payable check register, and vendor list. Ideal for analyzing expenditures by vendor and by due date.

• General Ledger— Includes lookup and change, making journal entries, trial balance, transaction register, chart

of accounts, financial statements, and monthly closing.

• Job Costing — Provides work order lookup, enters labor transactions, material set-up, progress report of hours, labor distribution report, weekly labor reset, actual versus estimated cost per job.

• Inventory — Can be connected with cash register for point of sale inventory control. Number of on-line items limited only by disk space available.

• Cash Register — Creates daily sales reports containing information on gift certificates, paidouts, overrings, refunds, and how much in each category a salesperson sold.

• Payroll — Handles 100% of all necessary payroll functions including state income tax tables for your state. Ideally suited for both large and small companies.

• Apartment— Said one user, "Obviously, this was developed by apartment owners." The package fills virtually all the needs of apartment owners and managers. Ideal for projects with 75 units or more.

• CBASIC-2 — The most comprehensive and powerful commercially oriented BASIC available today. Enhancements over CBASIC-1: integer variables, multiple line functions, CHAINing with COMMON variables, additional predefined functions, etc.

Compatible with many computers: Northstar, IMSAI, Altos, Cromenco, Industrial Micro Systems, Radio Shack TRS-80 Model II, SD Systems, Digital Microsystems, Dynabyte DB8/2, Micropolis MOD II, Vector MZ, and other 8080, 8085, and Z-80-based systems.

See your GDSS dealer or send for information packet and sample runs.

cs^a

Circle 224 on inquiry card.

Graham-Dorian Software Systems, Inc.

A Division of Graham-Dorian Enterprises

211 N. Broadway / Wichita, KS 67202 / (316) 265-8633

The Microcomputers you should take seriously.

The Challenger III Series is the microcomputer family with the hardware features, high level software and application programs that serious users in business and industry demand from a computer system, no matter what its size.

Since its introduction in August, 1977, the Challenger III has become one of the most successful microcomputer systems in small business, educational and industrial development applications. Tens of thousands of Challenger Ill's have been delivered and today hundreds of demonstrator units are set up at systems dealers around the country.

The Challenger III systems offer features which make their performance comparable with today's most powerful mini-based systems. Some of these features are:

Three processors today, more tomorrow.

The Challenger III Series is the only computer system with the three most popular processors— the 6502A, 68B00 and Z-80. This allows you to take maximum advantage of the Ohio Scientific software library and programs offered by independent suppliers and publishers. And all Challenger Ill's have provisions for the next generation of 16 bit micros via their 16 bit data BUS, 20 address bits, and unused processor select codes. This means you'll be able to plug a CPU expander card with two or more 16 bit micros right in to your existing Challenger III computer.

Systems Software for three processors.

Five DOS options including development, end user, and virtual data file single user systems, real time, time share, and networkable multi-user systems.

The three most popular computer languages including three types of BASIC plus FORTRAN and COBOL with more

languages available from independent suppliers. And, of course, complete assembler, editor, debugger and run time packages for each of the system's microprocessors.

Applications Software for Small Business Users.

Ready made factory supported small business software including Accounts Receivable, Payables, Cash Receipts, Disbursements, General Ledger, Balance Sheet, P & L Statements, Payroll, Personnel Files, Inventory and Order Entry as stand alone packages or integrated systems. A complete word processor system with full editing and output formatting including justification, proportional spacing and hyphenation.

OS-DMS, the software star.

Ohio Scientific offers an Information Management system which provides end user intelligence far beyond what you would expect from even the most powerful mini-systems. Basically, it

The Challenger HI

Series

from Ohio Scientific.

allows end users to store any collection of information under a Data Base Manager and then instantly obtain information, lists, reports, statistical analysis and even answers to conventional "English" questions pertinent to information in the Data Base. OS-DMS allows many applications to be computerized without any programming!

The "GT" option yields submicrosecond microcomputing.

Ohio Scientific offers the 6502C microprocessor with 150 nanosecond main memory as the GT option on all Challenger III Series products. The system performs an average of 1.5 million instructions per second executing typical end user applications software (and that's a mix of 8, 16 and 24 bit instructions!).

Mini-system Expansion Ability.

Challenger III systems offer the greatest expansion capability in the microcomputer industry, including a full line of over 40 expansion accessories.

Networking and Distributed Processing

OS-65U level 3 now provides networking capabilities as well as time sharing ability allowing Challenger III based systems to be expanded to meet the most demanding business applications.

Prices you have to take seriously.

The Challenger III systems have phenomenal performance-to-cost ratios. The C3-S1 with 48K static RAM, dual 8" floppies, RS-232 port, BASIC and DOS ■ has a suggested retail price of under $4000. 80 megabyte disk based systems start at under $13,000. Our OS-CP/M software package with BASIC, FORTRAN and COBOL is only $600, and other options are comparably priced.

For literature and the name of your local dealer, CALL 1-800-321-6850 TOLL FREE.

Circle 225 on inquiry card.

C3-S1

C3-B wins Award of Merit at WESCON 78 as the outstanding microcomputer application lor Small Business.

C30EM