[editor : Carl T. Helmers Jr.] [publisher : Virginia Londoner, Gordon R Williamson] [art : Wai Chiu Li, Christine Dixon, Holly Carmen LaBossiere, Deborah Porter] [nota bene : Missing pages and shuffled pages in archive.org. Full version in vintageapple.org] #Magazine
#Abstract
This month's cover features Hewlett-Packard's new bar code loader. The unit is described in detail in Carl Helmers' editorial on page 6. Bar codes, have been around for several years, in one form or another, but the HEDS-3000 Digital Wand is the first serious attempt to make bar codes a part of personal computing. Bar code readers will soon be used to enter recipe information into your microwave oven, read the bar codes on groceries, and enter programs into your computer. Also in this issue are several articles dealing with computer music. A lot has happened since our last special issue on music in September, 1977. Many of the new computers feature sound effects as a matter of course, such as the Atari and Texas Instruments models. This month Hal Chamberlin talks about recent developments in digital-to-analog (D/A) techniques for multiple-voice music generation; Jef Raskin describes a musical "amanuensis" or computerized music stenographer (the first of two parts); and Randolph Nelson reveals the details of how to enter and modify musical information into a computer quickly and efficiently.
[author : Carl Helmers] #Edito
Extract : « It was with great excitement that I opened a package which recently arrived from Hewlett-Packard's Optoelectronics people in Palo Alto, California. This package contained one of the first production versions of the model HEDS-3000 bar-code data-entry wand. A photo of the wand as it came to us was prepared by Ed Crabtree as a cover for this April 1980 issue of BYTE. The bar-code reader opens the way to a whole new field of applications of small intelligent processors.
As long-time readers of BYTE will recall, we have in the past presented no small amount of information on the concept of printing digital information in bar-coded form as a method of economically distributing data or programs for use in a personal computer or other local processors. (See page 10 for "A History of Bar Code Information Published in BYTE.") The idea is to treat the printed medium as a means of distributing data. With five centuries or so of technological progress since Johann Gutenberg's day, the techniques of making a good image on paper have been fairly well debugged. [...] »
TABLE OF CONTENTS
If you cannot afford both a set of tortoise-shell casting wands and a personal computer, you should buy the computer and use the program in this article to peer into the Book of Changes.
[author : Dr Edwin Dethlefsen] #Listing #BASIC #Book
Extract : « Today most people think of the I Ching (or Yi Ching or Yi King) as a kind of oriental fortune-telling game. Actually, it goes back long before the time of Christ. It was begun in the Chou dynasty in the 12th century BC and was mostly completed in its present form about 900 years later. Even Confucius is supposed to have tried it. It originated as a philosophical manual and set of exercises for looking at one's world and its problems in the broadest and most perceptive possible way, a little like the idea of "making your own luck" while pretending that what happens is just "the breaks"
You can read and enjoy the I Ching just like any book of rather esoteric oriental poetry, but that's really for the literary folks. Most of the college students who become involved with it attempt to use the book as a kind of reference for predicting the future or for figuring out solutions to such deep, personal problems as, "Does he really love me?", or, better yet, "What's the best way to make some money fast?"
I first became interested in the I Ching when I was a college student more than 30 years ago, because it was a terrific way to attract the attention of the opposite sex. Helping young ladies "cast" their fortunes was a foolproof way to get their undivided, personal attention.
Doing the I Ching thing is a very absorbing and satisfying pastime, once you understand how to play the game. Since there are several popular books written on the subject, I won't attempt to tell you all about it here, but I will talk about how easy it is to get a microcomputer to do the mechanical parts in a properly mystical fashion. I'll also say a little bit about how to consult this magical oracle. (It really is more magical than you might think, since the limits to its magical powers of knowledge are only determined by your imagination. Everyone I have ever seen use the I Ching has marvelled at its wondrous powers.) [...] »
Here is a demonstration of some disk file management techniques used in a delightful game program.
[author : Joseph J Roehrig] #Listing #BASIC #Game #Simulation #DataManagement
Extract : « The purpose of this article is to present a sophisticated horse racing game and to demonstrate the use of sequential and random access disk files. The first part of the article will describe the racing simulation, while the second part will detail the implementation of disk files, including the computer time required for certain operations. In addition, the second part will illustrate how the horse racing model can be utilized without using disk files, while limiting the memory requirements.
The Race game was written in North Star BASIC for a system having an 8080 processor, a video terminal, and 32 K bytes of memory. The program contains numerous subroutines, and memory can be saved by eliminating some of them. However, each deletion of a subroutine will also cause the loss of one of the game's features. [...] »
Programming this erasable programmable read-only memory for 8080-based microcomputers is easy with this author's hardware building and software usage methods.
[author : Robert Glaser] #Memory #Electronic #Listing #Assembly
Extract : « Erasable programmable read-only memories (EPROMs) can be used to great advantage in many microcomputer applications. One of the stumbling blocks to more widespread hobbyist use of EPROMs has been the difficulty of programming them. Several companies offer programming services, but this can be time- consuming as well as expensive.
One of the first EPROMs to become available was the 1702 device, which is structured as 256 words by 8 bits. This EPROM is indeed difficult to program. All of its address and data lines must be switched at 50 V levels, requiring a multitude of level-shifting transistors, in addition to the timing logic. Although it is possible to construct a programmer for the 1702, it is certainly not simple.
Salvation for the hobbyist came with the Intel 2708 EPROM. This device sports 1 K words by 8 bits of memory, four times the capacity of the 1702. [...] »
Here is a simple interface you can add to an Apple II to allow audio input and output.
[author : Mark A Cross] #Audio #Electronic #Listing #BASIC #Assembly #Book
Extract : « Tired of poking single tones into your speaker? The Apple is capable of talking or playing several notes simultaneously. It can be done in one evening from very simple homebrew interfaces.
There are at least three ways to get speech out of an Apple. The APPLE- TALKER program by Bob Bishop accepts voice from the cassette input, processes and stores the data, and then pokes it to the internal speaker. A second way is to use a voice synthesizer built on a plug-in card, such as the one made by Mountain Hardware. The third method is described in this article.
The references give the theory behind the methods of analog-to- digital (A/D), input, data storage, digital-to-analog (D/A), and output. They emphasize high sampling rates. Yes, it would be best to sample the input at 100 kHz and store it with 12-bit accuracy to create a high- fidelity computer. This is needed for music, but we are accustomed to sloppy speech. We can sample speech at 2000 Hz, store the data, and send it out to a 4-bit digital-to-analog converter. This reproduces speech which sounds very similar to that reproduced by a tape recorder! [...] »
Do you need to change the programs in your erasable programmable read-only memory? Try building this ultraviolet EPROM eraser to do the job.
[author : L B Golter] #Memory #Electronic
Extract : « The common 1702A, 2708, and 2716-type erasable programmable read-only memory devices (EPROMs) may be erased dozens of times and then reprogrammed, changing the internal bit pattern. The erasure is accomplished by exposing the silicon die to short-wavelength ultraviolet light through the quartz window. (The wavelength of the ultraviolet radiation in this instance is 2537 A.) National Semiconductor's recommended integrated dose (intensity times exposure) is 6 Ws/cm 2 (Watt- seconds per square centimeter). They recommend also that the exposure be triple the time for erasure found empirically. [...] »
In the first of two parts, this author explores several musical concepts and poses some of the initial music-to-printed-score translation problems.
[author : Jef Raskin] #Audio
Extract : « It is the dream of many amateur and some professional composers to have a machine that relieves the tedium of writing down musical ideas. The notation of music is not terribly difficult to write, but it takes a number of years of practice before you can do it quickly and legibly. Unfortunately, many composers never attain the goal of readability.
There are several kinds of systems that might appeal to a composer who wants good-looking scores. One might be a display-based music editor. Picture the composer seated before the display, light pen or graphic tablet in hand, writing on the display much as he now writes on paper. The computer's editing power would just make the process easier and more efficient. This is fine for the composer who does not use a musical instrument as he composes, but who sits at a desk with pencil and paper and is able to write down musical thoughts without having to play them.
Other composers actively use an instrument as they write, much as some people write prose more effectively by dictation rather than with a typewriter or a pen. It is this kind of keyboard-based system that is discussed here. [...] »
Having a text formatting routine when you output large amounts of text is useful. Now you can see how easy it is to implement an editor in BASIC.
[author : Robert G A Goff] #Listing #BASIC #Office
Extract : « While text editors are, in general, extremely useful for preparing all sorts of paperwork, it is usually not possible to append them to your own BASIC programs. This article is a simple tutorial in the bare essentials of text editing in BASIC. With these techniques, it will be possible for you to add simple text processing capability to any of your personal or business programs written in BASIC, which require paragraphed textual output. The program is written in North Star BASIC, version 6, release 3. It may be stored, as is, in 3186 bytes; it executes in a total of 4746 bytes. Deleting the remark statements reduces the program length to 1410 bytes enabling it to execute in 2956 bytes. While listing 1 is fairly self-explanatory, I'll discuss each of the steps in detail. [...] »
Last month, Steve told us about the 8088 processor's capabilities. Now he discusses a two-user system with Tiny BASIC that can be built using only five integrated circuits.
[author : Steve Ciarcia] #Microprocessor #Electronic
Extract : « In computer club meetings, in software-development groups, and among hardware designers, the terms multiprogramming, multiprocessing, and multitasking are often heard. Now that we have a few years of experience in microprocessing, the prefix multi has become prevalent. I define multi as an indication of the ability of a system to seemingly process more than one function at a time.
Multiprogramming, as I refer to it, is a form of program execution that allows more than one user to access the resources of a computer system at (apparently) the same time. Rather than denoting the execution of multiple programs simultaneously, which requires the use of more than one processor, multiprogramming implies a division of a single processor's time and resources. A computer executes commands faster than any single human user can enter data or instructions. A user in such a situation may never realize that there are other users connected to the same computer. [...] »
This well-known computer music maker discusses the fine points of how he uses versatile digital-to-analog converters with a typical personal computer.
[author : Hal Chamberlin] #Audio #Listing #BASIC #Assembly #HowItWorks #Book
Extract : « At this time, sound and music synthesis is a well established application of small computer systems. Currently there is some kind of music program for every microcomputer system known to the author; even a musical calculator advertisement has been seen (the unit also calculates). All of the recently introduced packaged personal computers have some kind of built-in provision for sound generation, and while aimed primarily at sound effects for games, all have music programs of varying degrees of sophistication. Several independent manufacturers offer more serious music software systems, most of which make use of specialized music hardware as well. All in all, music synthesis on personal computer systems is taking on greater importance every year and soon may approach the popularity of accounting, word processing, and games as a major application area.
Programmed performance of music by a low-cost microcomputer has many "practical" applications beyond the sheer gratification of coding the score, orchestrating the piece, and hearing the results. I have heard from a man who has taken the four-voice synthesis program from my previous article "A Sampling of Techniques for Computer Performance of Music" (September 1977 BYTE, page 62) and used it extensively in producing commercial music for radio and television advertising (about 75% of all such music is synthesized nowadays). [...] »
Here is a homebrewer's explanation of how formulas and guidelines were developed for choosing a particular electronic component.
[author : John Thomas] #Electronic #Book
Extract : « Typically there are four functional elements in a homebrew computer power supply. These elements are: the transformer, full-wave bridge rectifier, filter capacitor, and one or more integrated circuit voltage regulators as shown in figure 1. Experience has shown that most homebrewers have little difficulty in choosing any of the components, except when it comes to finding the value of the filter capacitor. Then they must resort to methods of multiple approximation, charts and graphs, or the better known and widely used method of trial and error. The following information will simplify the process of finding the smallest value of capacitance that will work in the circuit. [...] »
Now you can learn to enter musical scores into your computer by using a graphics tablet.
[author : Randolph Nelson] #Graphics #Audio #Book
Extract : « This two-part article describes the design of a musical text editor which could be implemented on a home computer graphics system. It is intended to be an overview of the basic design (part 1), along with the essential algorithms (part 2). A complete description of the system would take too much space. The editor allows a user to input a score of music and make corrections or modifications to it. The program stores the score, alters it according to the commands of the user, and displays the music on a graphics screen. All formatting, staffing and arranging of the score on the screen is done automatically by the program. Using the editor requires no special skills or knowledge. Before discussing the editor, it might be helpful to review musical notation. [...] »
An Animated Slot Machine in Color
A White Noise Generator for the Apple II
MicroShakespeare
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