[editor : Carl T. Helmers Jr.] [publisher : Wayne Green] [cover : Robert Tinney] [art : Nancy Estle, Neal Kandel, Peri Mahoney, Bob Sawyer] #Magazine
#Abstract
In the Christmas BYTE you'll find the following morsels:
To quote an ancient philospher, "nature abhors a vacuum." Chris Ryland's Opinion: The Software Vacuum describes a void in the personal use computer marketplace. Will nature in the form of profit motive come in and fill the software vacuum? Only time will tell ...
Strange things sometimes occur in the electronic pathways of a computer. Putting on your detective hat may occasionally be required - in which case Alex. F. Burr's review Logic Probes - Hardware Bug Chasers will give you valuable information on several commercial products which can help debug your designs.
On the same theme but in the foreground this time, Robert Baker and John Errico have provided an article on a fairly sophisticated Powerless IC Test Clip which you can construct for $20 or so in parts. For the do-it-yourselfer, this design results in 16 little binary voltmeters which can be clamped onto an integrated circuit to examine the logic levels at each pin.
What is a Character? You can find out by reading Manfred Peshka's tutorial on some of the basic concepts of programming and information systems work. Old hands at the programming arts will find this to be an interesting review, and readers new to programming will find it necessary background material.
After an interruption, the LIFE Line series continues this month with the third installment. In LIFE Line 3 you'll find the beginning of information on the interactive commands which are decoded by the program.
The Flip Flop is an important element in designs used with computer chips and peripherals. William E. Browning has provided this article to introduce the less experienced readers to this fundamental building block.
Read Only Memory Technology can be used in situations ranging from clever logic and interface design to storage of systems programs in a computer. In his article on the subject in this issue, Don Lancaster gives some background information about ROM applications and several suggestions concerning their use as design elements.
What is The World's Smallest Computer System? Well, at this time it looks like the HP-65 pocket-size programmable calculator might qualify for the title. Find out why by turning to Richard Nelson's article on the subject.
The last BYTE featured a comparison of the Motorola 6800 CPU chip with a new contender from MOS Technology. In this issue, Gary Kay of Southwest Technical Products Corporation presents some information on the Motorola 6800 package his firm is supplying. What SWTPC has done is to take the standard parts, combine them with an attractive case, power supply and PC boards - and put the result into a package as a kit for readers to build.
What is it like to build an Altair computer kit? In his First Person Report: Assembling an Altair, John Zarrella describes his experience with the MITS product, from his decision to purchase, through assembly and hardware debugging.
Computers are fundamentally synchronous machines they beat to the tune of a periodic clock. With program timing loops, a computer can be made to count the beats of its clock. You can find out how to do this by reading Jim Hogenson's article Can Your Computer Tell Time?
When assembling complicated logic systems, one of the best methods for new and experimental work is use of solderless wire wrap interconnection. Some pointers on prototype assembly are found in Photographic Notes on Prototype Construction.
And on the cover, artist Robert Tinney illustrates the impact of these new toys upon traditional relationships.
[author : Carl Helmers] #Edito
Extract : « Is a Good 8- Bit High Level Language
Have you ever tried to talk to a person who speaks a language other than your own? You know that the person must think as a rational, sentient being or you wouldn't make the attempt to communicate. As a human being your conversational partner's basic thought patterns are of necessity similar. Yet you can't understand him and he can't understand you. There are ways around this problem, given a sincere interest in communications by both parties. [...] »
TABLE OF CONTENTS
[theme : Test Equipment] [author : Baker] [contributor : Errico] #Electronic #Diagnostic
Extract : « This test clip operates like the expensive, commercially available clips selling for $85 or more without requiring batteries or external power. All types of ICs may be tested (TTL, OTL, MOS , etc.) and LEOs are used to indicate the logic state of each pin being tested. [...] »
[theme : Applications] [author : Helmers] #Simulation #Algorithm
Extract : « Program design is a process which can be approached in a haphazard manner - or by a systematic exploration of what is needed to achieve the desired end. LIFE Line 2 in BYTE #2 began the systematic exploration of the Tree of LIFE by presenting information on the overall program design of LIFE, as well as the details of the GENERATION algorithm used to carry one generation of LIFE into the next. LIFE Line 3 continues the development of LIFE by a discussion of the KEYBOARD_INTERPRETER procedure. This procedure monitors the "user inputs" of a keyboard, and uses the command keystrokes detected to dictate what LIFE will do. As in the exploration of the GENERATION algorithm, the presentation starts at the top and works downward. [...] »
[theme : Hardware Review] [author : Kay] #ComputerKit #Build
Extract : « If you are one of the many people getting ready to purchase one of the reasonably priced microprocessor system kits on the market today, you might ask yourself whether or not you will be able to start entering programs once you get it all put together. Of course you can always load programs and data through the front panel programmer's console, but most individuals aware of the front panel's slow speed and difficult readability prefer to use a Teletype or low cost video terminal such as the TV Typewriter II (February 1975, Radio Electronics) for data and program input/output. This is all well and good except that in order to attach a terminal, you'll have to purchase an interface for your computer if it is not supplied with the basic system. In fact you will generally need a separate interface for each I/O (input/output) device connected to your computer. This can run your system investment up considerably since such interfaces typically cost between $75 and $150 each, and there are more surprises yet to come. [...] »
[theme : Applications] [author : Hogenson] #Algorithm #Listing #Assembly
Extract : « Can your computer tell time? O. K. Now take away the LSI clock chip, pocket watch, grandfather clock, or whatever else you managed to interface together. Can your computer still tell time? You bet it can! It is a readily accepted fact that almost any type of hardware logic device can be imitated or simulated by computer software. That can also include timing devices if you wish . We will examine a few methods and considerations for software timing, then apply what we've learned in making a novel "software only" clock which will keep time as well as any conventional clock. The most efficient method (efficient referring to memory space used) to [...] »
[theme : Hardware] [author : Helmers] #Electronic
Extract : « The board which was photographed for this photo essay is the prototype Motorola 6800 system which is being designed and constructed for the LIFE Line application. [...] »
[theme : Opinion] [author : Ryland] #GeneralQuestions #Software
Extract : « There is a software vacuum. That fact has become increasingly clear in the past few months. Take a look at the situation. At the time this is written there's only one company (MITS) offering a proprietary software product (BASIC) aimed directly at the microcomputer hobbyists. It's true that the People's Computer Company (PCC), the MITS Altair User's Group, and a handful of other user groups offer access to growing libraries of applications programs. Some microsystem manufacturers also supply "bare bones" system software with their machines, but the user is lucky if these bones consist of as much as a rather bare monitor, editor and assembler. Such software is just as important to a serious hobbyist's system as the hardware. So when I say there is a software vacuum, I mean there is an absence of commercially developed and marketed larger scale software products. But why should this matter to me, as a hobbyist? [...] »
[theme : Tools] [author : Burr] #Electronic
Extract : « Digital logic, whether used in an 8080 microprocessor or as the TTL chips that can be used to make a processor, is, at least in theory, clean and simple because only two states are possible. Any point in even the most complicated circuit is either HIGH or LOW. However this very simplicity encourages the design of large and complicated circuits. While the chance of anything going wrong at anyone point is small, the accumulated chances of many points means that sooner or later the experimenter is going to have to hunt for sources of trouble. [...] »
[theme : Fundamentals] [author : Peshka] #Encoding
Extract : « A character is a unit of information used in a communication between a sender and a receiver. Senders and receivers may be either people or machines, or a mix of the two. A character may be represented in different forms: People use mostly graphics, such as the letters of the alphabet, the digits or occasionally the Roman numerals, and the punctuation and special symbols which are so familiar to us. Machines process a set of electric pulses in a period of time which normally represents a character. This time period differs in length for different devices; it is longer for slow devices (terminals, card readers, printers) than for fast devices (tape and disk drives), and is generally the shortest for the computer arithmetic and logical unit. [...] »
[theme : Hardware] [author : Browning] #Electronic
Extract : « One of the important building blocks in working with transistor-transistor logic is the flip flop. It is important to understand this building block if you desire to use it in projects of your own. The two most common types of flip flops are known as the JK flip flop and the D flip flop. [...] »
[theme : Hardware] [author : Lancaster] #HowItWorks #Memory
Extract : « Read Only Memories are a useful element of the hardware of microcomputer systems. This month, Don Lancaster provides information on Read Only Memories - a tutorial article taken from Chapter 3 of his forthcoming book, TV Typewriter Cookbook, to be published by Howard W. Sams, Indianapolis, Indiana. [...] »
[theme : Systems] [author : Nelson] #Review #ComputerPortable
Extract : « On Jan. 17, 1974, Hewlett-Packard announced their fourth model in a continuing series of sophisticated pocket calculators. This model, the HP-65, was unique in that it was programmable and used magnetic cards to read and write user-written programs. One of the first questions asked about the new machine was, "Is it a calculator or a computer?" There is no question that the HP-65 is the most powerful computational tool in existence for its size and weight, but in terms of an Altair 8800, Mark I or Sphere microcomputer, how does the HP-65 stack up?
Computer vs. Calculator
In the classical definition of a computer, as described by Babbage, the HP-65 is indeed a computer. The HP-65 has conditional and unconditional branching, data storage, and a memory which can be used to store a program. [...] »
[theme : Hardware] [author : Zarrella] #Electronic #Experience #ComputerKit #Build
Extract : « My adventure with microprocessors began rather late in the hobby game, at the end of 1974. It was about this time, or so it seemed to me, that micros became the topic of conversation in anything related to computers and automation. With the IMP-16, the 8080, 8008, 4004, etc., it became clear that this was what the computer market was waiting for. However, it was the article on the MITS Altair in the January 1975 issue of Popular Electronics which finally did it. [...] »
#Association
#Book
Extract : « The Bugbook III: Micro Computer Interfacing by David G. Larsen, Peter R. Rony and Jonathan A. Titus. Published by E & L Instruments, Inc., 67 First St., Derby CT 06478; 1-203-735-8774. $14.95. [...]
Discovering BASIC - A Problem Solving Approach by Robert E. Smith, Hayden Publishing Co., New York NY, 7970. $7.95 hardcover, $5.95 paperback. [...] »