Vol.2 n°1 january 1977

Vol.2 n°1 january 1977

p.3 In the Queue (table of contents)

Foreground

p.18 MAKING HASH WITH TABLES

[theme : Software] [author : Dollhoff]

p.32 HOW TO DRIVE A TELETYPE WITHOUT A UART

[theme : Hardware] [author : Jewell]

p.34 SATURATION RECORDING'S NOT THAT HARD

[theme : Mass Storage Technology] [author : Allen]

p.82 THE BUILT-IN LOGIC TESTER

[theme : Hardware] [author : Christner]

p.91 BUILD THE "COFFEE CAN SPECIAL" EROM ERASER

[theme : Hardware] [author : Burbey]

p.92 SEPARATE YOUR SYNC

[theme : Hardware] [author : Rosen]

p.106 USING INTERRUPTS TO SPEED UP AN ELM

[theme : Software] [author : Gable]

Background

p.42 WATTS INSIDE A POWER SUPPLY

[theme : Hardware-] [author : Liming]

p.50 PICK UP BASIC BY PROM BOOTSTRAPS

[theme : Hardware-] [author : Kreitner]

p.56 BLACK FRIDAY

[theme : Software] [author : Baker]

p.60 TYPES AND USES OF DIRECT ACCESS STORAGE

[theme : Mass Storage Devices] [author : Hill]

p.66 SYS 8½... YOUR OWN EXECUTIVE COMMANDS

[theme : Software] [author : Nico]

p.78 COMPUTER MODELS FOR BOARD GAMES

[theme : Applications] [author : Yost]

p.116 A COMPUTER HOBBYIST CLUB SURVEY

[theme : Survey] [author : Caulkins]

Nucleus

p.2 In This BYTE

p.4 The Appliance Computer, Circa 1977

p.11 About the Cover

p.11 Machine Readable Printed Programs

p.11 Book Reviews

p.16 Letters

p.72, 84 What's New?

p.76 Description: Tutorial Training Computer

p.93 Answer to Software Bug 6

p.94 Description : OSI

p.96 Classified Ads

p.97 BYTE's Bugs

p.99,104,130 BYTE's Bits

p.100 Some Candid Shots from PC 76

p.114 Kil O'Byte

p.115 Clubs, Newsletters

p.119 Clubs, Newsletters Directory

p.140 Ask BYTE

p.144 BOMB

p.144 Reader Service

In this BYTE

Terry Dollhoff provides readers with some food for thought on hashing techniques. Turn to Making Hash With Tables to find out what it means to hash data as a method of improving table access time. The straightforward way of seeking data in a table (searching each element in turn) is far from the most time efficient, as you'll discover by considering Terry's arguments.

For an output only interface, you don't necessarily have to use a UART to drive a Teletype printer. Gregory C Jewell shows How to Drive a Teletype Without a UART using five standard TTL integrated circuits.

How do you drive a tape recorder's head directly, and read data directly? If you read David M Allen's article in this issue, you'll find out that Saturation Recording's Not All That Hard after all. David shows a simple tape driver circuit, input signal processor and the design of software for direct digital recording with audio tape heads on cassette recorders.

Watts Inside a Power Supply? Find out by reading Gary Liming's account of power supply basics. You'll find that there are indeed watts lost inside a power supply, the reason these items invariably come with some form of heat sink. After reading Gary's article you'll have some good background information in your memory banks for evaluating the various power supply schemes which are used in practice, and why such schemes are used.

Altair BASIC (in whatever form you have it) is an excellent aid to the utilization of an 8800 system. However, there is that residual problem of putting in a 20 byte bootstrap program every time you turn power on. In this issue, a short article by Jim Kreitner shows you how to Pick Up BASIC by PROM Bootstraps.

Who knows what the bears and bulls will be doing next in the stock market? Play Black Friday, a BASIC game by Bob Baker, and you'll get a heuristic feel for what happens through the powerful tool of simulation. Will X-Pando do better than Slippery Oil after a simulated year of trading? Play the game and find out.

Newcomers may wonder what is meant by the term "direct access storage device." This is the most useful form of mass storage, a form which is the dream and goal of every small system hacker who has passed the beginning stages of programming applications of his or her computer. To help define the terminology for the novice, reader Curt Hill has provided an elementary article on the types and uses of direct access storage.

The SYS 8 monitor as it is supplied by IMSAI and Processor Technology is a self-contained operating system for 8080 based microprocessors which comes equipped with its own set of executive commands. These commands are used for calling programs that are resident in the system. Wouldn't it be great if programs that are not part of the monitor could be part of the executive command table? This was the conclusion of Willard I Nico. He decided to have easy availability of his most used programs by adding them to the executive command table. He describes how you too can easily accomplish this in his article SYS 8 1/2 - Your Own Executive Commands.

Representations of two dimensional game boards as the bits of various bytes in your computer's memory can often be chosen to help facilitate evaluation and strategy computations. In Computer Models For Board Games, Russell R Yost Jr presents some basic background information on the problem and suggestions for representations useful in the games of TACTIX and HEXPAWN.

For use when testing out your hardware, the idea of The Built-In Logic Tester can prove quite useful. K W Christner discusses the concept in a short article on his version of a logic probe.

Riddle of the Month: What is not like an elephant with a suntan?

An EROM which forgets its memory pattern due to ultravilet light.

Build the "Coffee Can Special" EROM Eraser described by Lawrence Burbey in order to convert white elephant EROMs into blanks ready for reprogramming.

Video interfaces often produce an EIA composite video signal as the principal output. What do you do when you have a commercial digital monitor with separate sync inputs of the type used in display terminals? Why, that's when you follow David Rosen's lead and Separate Your Sync by tapping the interface at a nonstandard point.

June BYTE had an article on ELM, an Eloquent Little Monitor. In this issue, author G H Gable describes a method of Using Interrupts to Speed Up an ELM. The use of interrupts and a tape drive with a direct memory access interface make a valuable extension of the basic monitor concept.

In June and July a survey was conducted of computer hobbyist clubs in the US and Canada. The questionnaire covered such areas as number of members per club, types of computers owned, applications for the computers and the members' backgrounds. In his article, A Computer Hobbyist Club Survey, David Caulkins releases the results of the survey and explains some of the conclusions that he has reached as a result of the survey.