[editor : Carl T. Helmers Jr.] [publisher : Virginia Peschke, Manfred Peschke] [art : Mary Jane Frohlich, Bill Morello] [cover : Robert Tinney] #Magazine

#Abstract

What's good for about four billion bytes on line capacity, 10 to 50 ms access time, and a system cost in the personal computing category? Find out by reading Martin Buchanan's article on What Do You Do With a Video Disk?

"Friends, Humans, and Countryrobots. Lend Me Your Ears." When you've reached a point in your audio output micro-experimentation where the computer can talk, you'll have quite an accomplishment. D Lloyd Rice describes some of the background information needed to create a human vocal tract model with computer control in his excellent tutorial on the subject. Imagine, Star Trek implemented with a real ship's computer output!

What plugs into one Altair or IMSAI compatible bus slot, eats serial phoneme snacks, talks back and won't shut up till you pull the plug? Find out by reading Wirt Atmar's historical background and description of a new Altair compatible plug-in voice synthesizer, a commercial version of the prototype which was demonstrated as a prize winning entry in the recent MITS World Altair Computer Convention. Once you get the hang of its accent, your talking computer will add a new dimension to conversational software.

What's wrong with the 8080 processor architecture? Ask a programmer for "features" and you'll get some answers. An analysis followed by definition of improvements resulted in the new Zilog Z80 microprocessor which is the ultimate in 8 bit microprocessors at this point in time. Find out what the Z80 is all about by reading Burt Hashizume's Microprocessor Update: Zilog Z80.

The act of programming, like any act of creation, requires a bit of organization and discipline on the part of the thinker. In the second reprint from Nat Wadsworth's Machine Language Programming for the "8008" (and similar microcomputers) you'll find some thoughts on the design and planning of programs.

In May BYTE, we had A Date With KIM. Here is the next chapter in the continuing story of True Confessions: How I Relate to KIM. Turn to Yogesh M Gupta's account of modifications to the KIM-1 system which achieve compatibility with slower memories, bus expansion, and a priority interrupt capability.

A sub theme of this BYTE is the idea of the talking personal computer system. Well, Jack Hemenway and Robert Grappel got together recently to concoct an allegorical tale of Jack's assembler. In Jack and the Machine Talk you'll see a dialogue with a computer personified. Which leads to the next step: Who'll be the first reader to create a program to implement the computer side of the dialogue, using one of the new voice output devices which are coming to market?

Want to experiment with high level languages (like APL) that require an extended character set? Want to simply build and utilize a convenient text display output device? Need upper and lower case displays for a text editor? If so, and if you can get by with a 32 character line on a standard TV set or monitor, then Dr Robert Suding's latest article will be of interest. Build a TV Readout Device for Your Microprocessor using his detailed design.

What's an I2L? Terry Steed en has written a short background summary of this relatively new logic family, one which has important manufacturing and power consumption advantages which assure its place in the stable of semiconductor fabrication methods.

Many readers have found real bargains in older Baudot Teletype machines such as the Model 15 and the Model 19. The main problem, though, is Interfacing the 60 mA Current Loop to the normal TTL level signals of a typical microcomputer. One solution to this problem is provided by Walter S King's short article in this issue.

And for the cover, Robert Tinney portrays a scene from the near future.

[author : Carl Helmers] #Edito #Association

Extract : «  Mapping Sessions

On April 28 1976 I attended one of the biweekly meetings of the Homebrew Computer Club in Palo Alto CA with Dave Fylstra and Mike Wilbur of Stanford Research Institute as my guides. The meeting was most interesting from several points of view. One of the best features was the session of "mappings" which occupied the first portion of the evening's activity. This activity is one which would be well worth instituting by clubs elsewhere, so I'll describe my impressions.

The mapping session provides a mechanism for various members to advertise what they personally have to offer or what they are personally looking for. It is a way for the persons attending the meeting to find other persons with similar (or complementary) interests so that they can get together for exchanges of software, surplus components, expertise in fixing bugs, etc.

The key to the mapping session is a large set of people (in the Homebrew Computer Club, n≈400) and an efficient "moderator" to coordinate the session [...]  »

TABLE OF CONTENTS

[theme : Hardware] [author : Gupta] #ComputerKit #Electronic

Extract : «  I recently purchased a KIM-1 microcomputer card from MOS Technology (See "KIM-O-Sabee?" in the April BYTE, page 14 and "A Date With KIM" in the May issue, page 8). In my opinion, KIM-1 offers one of the best bargains to a computer experimenter for the price ($245 for the card + $4.50 for shipping and handling). However, the hobbyist may be faced with a few problems, as I was. The intent of this article is to solve some of these problems. [...]  »

[theme : Hardware] [author : Suding] #Interface #Display #Electronic

Extract : «  A television set readout for your microprocessor has many attractive advantages. The TV readout is vastly faster, quieter, and even lighter, than the usual Teletype based design. Since it is an electronic rather than mechanical device, less service and maintenance are required. Much more data may be contained on a television screen than on front panel readouts. [...]  »

[theme : Hardware] [author : King] #Electronic

Extract : «  Generally the older Teletype units such as model 15s, 19s and 28s require a 60 mA loop to operate the printer. These older machines are not as attractive looking as the newer model 32s and 33s, but for the Altair computer hobbyist, looks are probably second to costs. The 60 mA interface circuits shown below are simple, straightforward, and do an effective job. [...]  »

[theme : Speculation] [author : Buchanan] #Anticipation #Storage #Video

Extract : «  In one to three years, for less than $1,000, you should be able to buy a mass storage system with the following characteristics:
Directly accessible in 10-50 ms.
Data transmission rate of 15,000,000 bits per second.
On line capacity of 4,000,000,000 bytes.
Storage units costing $2 each.
The only limitation on the first such systems may be a "write once" limitation. Once something is recorded, it is recorded permanently. A California engineering consultant has told me that this limitation can be overcome, but I haven't researched the suggested techniques. The limitation isn't particularly serious because essentially infinite storage (50¢ per billion bytes!) will allow you to store each new version of a file or program in a new location. Not writing over old versions of files and programs will certainly aid documentation. [...]  »

[theme : Hardware] [author : Rice] #Encoding #Audio #Electronic

Extract : «  You've got your microcomputer running and you invite your friends in to show off the new toy. You ask Charlie to sit down and type in his name. When he does, a loudspeaker on the shelf booms out a hearty "Hello, Charlie!" Charlie then starts a game of Star Trek and as he warps around thru the galaxy searching for invaders, each alarming new development is announced by the ship's computer in a warning voice, "Shield power low!", "Torpedo damage on lower decks!" [...]  »

[theme : Voice Systems] [author : Atmar] #Audio #Electronic

Extract : «  The extent to which art and literature, particularly science fiction, affect the future course of civilization remains a persistent and perplexing question. Must a dream, by necessity, occur decades before its realization? Or does the presence of the dream itself generate its own reality? Mankind's trip to the Moon in 1969 was the dream dreamt by Cyrano de Bergerac and Johannes Kepler 300 years prior to its enactment. [...]  »

[theme : Hardware] [author : Hashizume] #Review #Microprocessor

Extract : «  Zilog, a fairly new company in Los Altos CA, has been sampling an 8 bit microprocessor, the Z80, since early this year. The Z80 is a "third generation," single chip, NMOS microprocessor, which is completely software compatible with Intel's 8080A. Its 158 instructions include the 8080A's 78 instructions as a subset. Because the 8080A is probably the most widely used 8 bit microprocessor on the market today and because of the Z80's upward software compatibility, this article evaluates the Z80 in comparison to the 8080A. [...]  »

[theme : Software] [author : Wadsworth] #Method #Algorithm #MachineCode

Extract : «  The first task that should be done prior to starting to write the individual instructions for a computer program is to decide exactly what it is that the computer is to perform and to write the goal(s) down on paper! This statement might seem unnecessary to some because it is such an obvious one. It is stated because the majority of people learning to develop programs will realize its significance when they discover, halfway through the writing of a large machine language program, that they left out a vital step. Such an error can typically result in the programmer having to start back at the beginning and rewrite the entire program. The practice of writing down just what tasks a particular program is to perform and the steps in which they are to be done, will save a lot of work in the long run. The written description should be as complete and detailed as necessary to ensure that exactly each step of the program will be clear when actually writing the program in machine language. It is generally wise for the novice programmer to take pains to be quite detailed in the initial description. [...]  »

[theme : Software] [author : Grappel-Hemenway] #Initiation #Assembly

Extract : «  One day in 1975, Jack Hemenway had finally had it with machine language. "I'm tired of address calculations in hexadecimal! I'm tired of looking up every opcode! My Motorola manuals are falling apart! I'm tired of midnight debugging from memory dumps! My eyes ache from reading page after page of hexadecimal! I need a good bookkeeper to help me write programs, someone who knows Motorola opcodes by heart, can compute in hexadecimal, is infallible! A bookkeeper I can really talk to!" [...]  »

[theme : Hardware] [author : Steeden] #Electronic

Extract : «  Everyone likes transistor-transistor logic, TTL. It is fast, cheap, widely available — and it consumes power. Not much power, compared to a vacuum tube, but a lot for integrated circuits, especially when compared to metal oxide semiconductors. And everyone likes MOS because of its low power consumption. But, it is typically not as fast as, and it is not as cheap as, the older TTL logic. This means that Large Scale Integration (LSI) chips either draw a lot of power (TTL) or are not as fast as they could be (MOS). But what would happen if the best of the two could be joined together? A fast, low power, cheap gate . . . Behold, I2L or "integrated injection logic." Let's see how low power and speed are combined cheaply. We can begin by looking at power consumption, cost, and speed, briefly, and then see what other observations we can make about I2L. [...]  »

#Book

Extract : «  Scelbi's Galaxy Game for the 8008/8080 by Robert Findley. Published by Scelbi Computer Consulting Inc, 1322 Rear — Boston Post Rd, Milford CT 06460, 1976. $14.95 [...]  »

#Association