1975 1.06 1977

Vol.1 n°6 february 1976

Vol.1 n°6 february 1976

(byte_1976_02.jpg)

[editor : Carl T. Helmers Jr.] [publisher : Virginia Peschke, Manfred Peschke] [cover : Robert Tinney] #Magazine

p.2 In This BYTE

p.2 In This BYTE

#Abstract

How does a computer evaluate a complicated mathematical expression? There are many ways to accomplish this function. One technique is to use the My Dear Aunt Sally Algorithm which is described by Robert Grappel.

There is more than one way to Process Algebraic Expressions, of course. In his article on the subject, W.D. Maurer describes the Bauer-Samelson algorithm, which uses an operator stack and an operand stack to parse algebraic expressions.

How do bits get from one place to another? The design of Data Paths to convey information is an important consideration in any system. Gary Liming provides some background information on the subject.

MITS makes a 6800 product, too. James B. Vice of MITS describes his company's design in an article on The New Altair 680.

Hard copy can be created in many ways. Its purpose is to record information in a form which humans can interpret unaided. In How to Save the Bytes, Thomas Mcintire proposes a multiple-segment character set which might be useful for an inexpensive print mechanism.

Gary Kay continues a presentation of information on the Southwest Technical Products Corporation's 6800 system which was begun in BYTE No.4. This month's installment presents information about the memory boards, serial interface, control interface, parallel interface, power supply and case. The information is completed with a short discussion of available software and future additions to the system.

BYTE has published a few examples of LEDs used in test probes and diagnostic equipment. In his article E. W. Gray provides some basic information on the use of LEDs. After incorporating his suggestions you can have LEDs Light Up Your Logic in more ways than one.

One way to monitor digital data lines is simply to drive an LED based upon the steady state of the line. But what if you are dealing with occasional pulses? A simple indicator is the TTL Pulse Catcher described by Bill Walde, a test instrument which can be built from one IC, one LED, two switches and two resistors.

How do you generate graphics patterns for TV raster scanning? One answer is provided by Don Lancaster's discussion of Color Graphics Techniques.

Could a Computer Take Over? Ed Rush provides us with some thoughts on the subject with ample references to the speculative fiction of computer technology. We'll let readers draw their own conclusions.

Getting Information from Joysticks and Slide Pots is a problem which must be solved for interactive game purposes. One solution to the problem is shown in this issue.

And on the cover, artist Robert Tinney shows My Dear Aunt Sally at work tutoring a computer on the subject of interpreting arithmetic expressions.

p.4 Join the Club

p.4 Join the Club

[author : Carl Helmers] #Edito

Extract : «  I found an interesting quotation in the Wall Street Journal in a recent front page news analysis on the subject of philanthropy. The theme of this quotation is the American heritage of forming voluntary associations for specific purposes. "Americans of all ages, all stations in life, and all types of disposition are forever forming associations," wrote Alexis de Tocqueville in the 1830s. [...]  »

TABLE OF CONTENTS

Foreground

Foreground

p.16 KEYBOARD MODIFICATION

p.16 KEYBOARD MODIFICATION

[theme : Surplus] [author : Macomber] #Keyboard #Electronic

Extract : «  I read your article in the September 1975 BYTE on surplus keyboards with interest. I have made some simple modifications to produce lower case codes on RTL and DTL keyboards. I have a Southwest Technical Products keyboard which I have modified. I have also modified a Sanders 720 owned by a friend. [...]  »

p.54 LEDs LIGHT UP YOUR LOGIC

p.54 LEDs LIGHT UP YOUR LOGIC

[theme : Techniques] [author : Gray] #Display #Electronic

Extract : «  Of the many technological developments in recent years, perhaps none is more intriguing than the visible light emitting diode, or LED. This tiny semiconductor device, with its hypnotic red glow, is a far cry from the cat whiskered crystals which introduced so many of us old-timers to the wonderful world of electronics. A crystalline compound of gallium, arsenic, and phosphorous, the LED is a diode that emits visible light when forward biased. No attempt is made here to explain how the light emission works. Instead, this article shows how LEDs can be used to advantage as data displays, fault, and status indicators. [...]  »

p.58 BUILD A TTL PULSE CATCHER

p.58 BUILD A TTL PULSE CATCHER

[theme : Test Equipment] [author : Walde] #Electronic

Extract : «  While checking out the operation of some oneshots on the address latch board during the construction of my Mark-8 microprocessor, I discovered that my first home-made logic probe could not detect very short TTL logic pulses. Since my old probe would not work, I needed a quick and easy way to tell whether a short TTL pulse had arrived. I dreamt up this circuit which solved the problem by adding memory in the form of an RS flip flop wired from a NAND gate. [...]  »

p.60 DRESSING UP FRONT PANELS

p.60 DRESSING UP FRONT PANELS

[theme : Techniques] [author : Walters] #Build

Extract : «  To dress up panels of equipment use press on lettering (available from stationery shops, college and university book stores, and from graphics arts supply shops) to label the various functions performed by the components which will be mounted on the panel (see figure 1). The lettering can be pressed on, wire brushed, chemically etched, or painted surfaces. The only caution is that the surface be free of dirt and grease before applying the lettering to the panel. [...]  »

Background

Background

p.18 MY DEAR AUNT SALLY

p.18 MY DEAR AUNT SALLY

[theme : Algorithms] [author : Grappel] #Algorithm #Mathematics #Glossary

Extract : «  The number of mathematical operations a computer can perform without the aid of programming is quite small. The bare machine can add and subtract, and perhaps it can also multiply and divide. It cannot comprehend a series of operations, nor can it evaluate a mathematical expression as a human would typically write it. It cannot group operations as required by the rules of mathematics. All these require software; programs which convert mathematical statements to sequences of machine instructions. This article describes a set of programs which can read a mathematical statement in its normal form and evaluate its result. [...]  »

p.26 PROCESSING ALGEBRAIC EXPRESSIONS

p.26 PROCESSING ALGEBRAIC EXPRESSIONS

[theme : Algorithms] [author : Maurer] #Algorithm #Programming

Extract : «  To the amateur programmer, algebraic expression processing may seem a formidable obstacle. How do you write a program which takes a character string like 2+3*(4-(1 4/7-1)) as input, and produces the right answer — in this case 11 — as output? The programmer seeking answers to such questions is usually led to a collection of sources on compiler theory, and to arcane-sounding terms like "recursive descent," "top-down and bottom-up parsing," and the like. These were developed for use by the compiler writer, although even compiler writers find much of compiler theory interesting for theoretical purposes only. The net result has been, in all too many instances, to scare the ordinary programmer away from algebraic expressions entirely — a decidedly unfortunate state of affairs. [...]  »

p.32 DATA PATHS

p.32 DATA PATHS

[theme : Hardware] [author : Liming] #Electronic #Networks #Encoding #Interface #Glossary

Extract : «  Data transmission usually brings to mind terminals, telephone lines, satellites, and large computer centers. Computer links in retail stores, banks, airlines and government agencies are becoming more and more widespread. Such large scale operations can easily cost millions of dollars and are thus out of the range of the hobbyist. The prospect of linking home systems across distances for program swapping and interactive games will undoubtedly become more a possibility as the technology improves. [...]  »

p.42 THE NEW ALTAIR 680

p.42 THE NEW ALTAIR 680

[theme : New Product] [author : Vice] #Review #ComputerKit

(byte_1976_02_p042.jpg)

Extract : «  The new ALTAIR 680 designed by MITS is a system based on the 6800 microprocessing unit (MPU). The MPU is available from Motorola or American Micro-Systems and adapts nicely to a minimum design configuration. [...]  »

p.46 HOW TO SAVE THE BYTES

p.46 HOW TO SAVE THE BYTES

[theme : Man-Machine Interface] [author : McIntire] #Encoding

Extract : «  The personal computer is today, a real, affordable entity. A paradox is appreciated, however, when configuring a system. You can order a computer for less than a good color television. But talking to it costs much more. Computer communications, meaning the traditional twins of input and output, are commonly referred to as IO. The paradox is that it costs more to save the bytes than to process them. [...]  »

p.50 MORE ON THE SWTPC 6800 SYSTEM

p.50 MORE ON THE SWTPC 6800 SYSTEM

[theme : New Product] [author : Kay] #ComputerKit #Build

Extract : «  In the December 1975 issue of BYTE we talked about the microprocessor/system board (MP-A) and the mother board (MP-B) for the Southwest Technical Products 6800 microprocessor system. This article describes the serial control interface (MP-C), the 2,048 byte random access memory board (MP-M), the power supply (MP-P) and cabinet (MP-F). We will also talk about the serial interface boards (MP-S) and parallel interface boards (MP-L). [...]  »

p.62 TV COLOR GRAPHICS

p.62 TV COLOR GRAPHICS

[theme : Hardware] [author : Lancaster] #Electronic #Display #Graphics

Extract : «  A graphic display lets us add pictures, lines, and symbols to the basic letters and numbers of an ordinary TV typewriter so that it can be used in chess, for video art, for games, printed circuit layouts, logic diagrams, charts, and so on. For many TVT and microcomputer uses, the ability to display several colors at once is very important; for others, it is simply a convenience that may not be worth the extra complexity. [...]  »

p.76 COULD A COMPUTER TAKE OVER?

p.76 COULD A COMPUTER TAKE OVER?

[theme : Speculation] [author : Rush] #GeneralQuestions #Anticipation

Extract : «  Just how ridiculous IS the idea of a computer deciding to take over the world and be its dictator?

Upon hearing this question, most people who are not computer oriented will laugh and say "That's only in science fiction stories." They will be much more likely to complain about "becoming a number," with everyone from the grocery store to the government wanting their number instead of their name.

Those who are more familiar with computers will laugh off the concept and charge it to paranoia due to ignorance. "A computer is little more than a lot of wires conducting currents here and there," they will say. "Besides, if it gets uppity you can always pull the plug." [...]  »

Nucleus

Nucleus

p.10 Letters

p.10 Letters

p.14 Our New Offices

p.14 Our New Offices

p.31 p.83 BYTE's Bits

p.31 p.83 BYTE's Bits

p.41 Chips Found Floating Down Silicon Slough

p.41 Chips Found Floating Down Silicon Slough

p.61 Classified Ads

p.61 Classified Ads

p.69 Numbers

p.69 Numbers

p.70 Clubs, Newsletters

p.70 Clubs, Newsletters

#Association

p.72 Audio Cassette Standards Symposium

p.72 Audio Cassette Standards Symposium

p.74 View From Silicon Valley

p.74 View From Silicon Valley

p.84 8080 Op Code Table

p.84 8080 Op Code Table

p.92 Book Reviews

p.92 Book Reviews

#Book

Extract : «  Computer Models of Thought and Language edited by Roger C. Schank and Kenneth Mark Colby. Published in 1973 by W.H. Freeman and Company, San Francisco CA. [...]

When Harlie Was One by David Gerrold, Ballantine Books, 1972, 279 pp. paper-bound, $1.50. [...]

The Shockwave Rider by John Brunner, Harper & Row, 1975, 246pp., $8.95. [...]  »

p.95 BOMB

p.95 BOMB

p.96 The BYTE Questionnaire

p.96 The BYTE Questionnaire

p.96 Reader's Service

p.96 Reader's Service

ADS (content taken from the reader service p.96)

ADS (content taken from the reader service p.96)

(p.CIII) ACM

(p.CIII) ACM

p.61 Advanced Data Sciences

p.61 Advanced Data Sciences

p.93 BYTE Subscription

p.93 BYTE Subscription

p.90 BYTE's Books

p.90 BYTE's Books

p.75 Celdat Design Associates

p.75 Celdat Design Associates

p.73 Centi-Byte

p.73 Centi-Byte

p.9 Continental Specialties

p.9 Continental Specialties

p.31 Cromenco

p.31 Cromenco

p.85 Delta Electronics

p.85 Delta Electronics

p.83 Dutronics

p.83 Dutronics

p.5 Godbout

p.5 Godbout

p.59 IMS Associates

p.59 IMS Associates

p.71 Intelligent Systems

p.71 Intelligent Systems

p.91 Interface

p.91 Interface

p.81 International Electronics Unltd.

p.81 International Electronics Unltd.

p.79 James Electronics

p.79 James Electronics

p.89 Meshna

p.89 Meshna

p.37 Micro Digital

p.37 Micro Digital

(p.CIV) MITS

(p.CIV) MITS

p.3 MITS

p.3 MITS

p.13 MITS

p.13 MITS

p.35 MITS

p.35 MITS

p.65 National Multiplex

p.65 National Multiplex

p.73 Ohio Scientific Instruments

p.73 Ohio Scientific Instruments

p.48 p.49 Processor Technology

p.48 p.49 Processor Technology

p.7 Scelbi Computer Consulting

p.7 Scelbi Computer Consulting

(p.CII) Southwest Technical Products

(p.CII) Southwest Technical Products

p.17 Sphere Corporation

p.17 Sphere Corporation

p.57 Systems Research

p.57 Systems Research

p.40 Techtra

p.40 Techtra

p.75 Tri Tek

p.75 Tri Tek

p.15 Wave Mate

p.15 Wave Mate

p.61 Wintek

p.61 Wintek