[editor : Carl T. Helmers Jr.] [publisher : Virginia Peschke, Manfred Peschke] [art : Bill Morello] #Magazine
#Abstract
What does it take to make your microcomputer keep track of that small spare time "moonl igh tn business? For small businesses, one of the biggest problems is all the paperwork required of the entrepeneur. John A Lehman provides an introduction to the subject of automated accounting procedures in his description of A Small Business Accounting System.
Find out how to Build a Television Display which can be interfaced to your computer's memory address space by consulting C W Gantt Jr's article on a 15 IC controller for a 32 by 16 display.
Programming to a large extent is organizing your ideas about what the computer should do. Ronald T Herman gives some basic pointers on Programming for the Beginner, concerning the practice of structuring program designs into well defined verbal descriptions, before you generate a single line of code. This practice makes programming easier and less subject to nasty errors which interfere with the goal of a working application.
Is your high school's computing budget crimped ? Use Christopher Lett's experience with A High School Computing System as a way to show that a small budget does not necessarily rule out getting a system.
A Systems Approach to a Personal Microprocessor is the inaugural article in a new series of detailed design articles which is being prepared for BYTE by Dr Robert Suding. In this first instalment, you'll find some of Dr Suding's views on the philosophy of system design, to lay the groundwork.
Build a computer? Sure. Bob Abbott shows you the circuitry and some photos of a wire wrapped M6800 system in his article on Building an M6800 Microcomputer.
One of the principal uses of a computer is data processing. Phillip L Hansford describes one simple data processing application which he implemented with minimal equipment: How to Strike a MATCH between penpals for his penpal club.
Last month, Bob Nelson introduced "Chip" Off the Olde PDP 8/E. In Part 2, he discusses the interrupt structure, control panel features and support chips of the Intersil IM6100 design.
One key component of system software for any computer is a monitor program. You can find out how to program and Interact with an ELM (Eloquent Little Monitor) by reading G H Gable's article on his design of a handy piece of system software.
Techniques of developing the effective address for operands in memory vary with the choice of CPU. In An Introduction to Addressing Methods. John Zarrella discusses some of the classical ways computers use to calculate the address of operands in memory. You can use this background information in forming your own opinion about the instruction sets of the various miCrocomputers presently available.
What's in a language? Nat Wadsworth and Mark Arnold present some information on their interpretive language system, SCELBAL, in a product description article.
[author : Carl Helmers] #Edito #Interface #Standard
Extract : « The idea of a parallel interface standard which encourages interesting combinations of peripherals and processors from different manufacturers is one which in my opinion should be pursued to help foster the growth of the personal computing marketplace, a growth which will provide a wider range of options for both users and suppliers of products.
The User's Eye View
The need of a parallel interface standard from the user's point of view is readily perceived. The parallel interface standard will be the personal computing equivalent of what exists in the audio equipment industry: a widely manufactured, readily available physical interconnection with logically and electrically compatible signal definitions. The plug of choice in the audio field is the RCA style phono plug universally used to interconnect low level audio signals via shielded cables. This enables the purchaser of brand X turntable to plug it into a brand Y receiver using shielded cables of brand Z. [...] »
TABLE OF CONTENTS
[theme : Hardware] [author : Gantt] #Electronic #Display
Extract : « As a small system expands and becomes more sophisticated, the limiting factor is often the speed of input and output (IO). In addition to being noisy, mechanical, and paper consuming, the slow clacking of a TTY may account for a large percentage of system time. Among the alternatives, the display of characters on a standard TV set is among the simplest and most economical methods. [...] »
[theme : Hardware] [author : Abbott] #Electronic #ComputerKit #Build
Extract : « Early in the introduction of the Motorola 6800 system, an "Evaluation Kit" of seven family chips was made available. This kit contains the microprocessor, a read only memory preprogrammed with a system monitor called MIKBUG, two 128 by 8 bit random access memories, two peripheral interface adaptors and an asynchronous communications interface adaptor. These chips are all M6800 family-members, intended to work together and demonstrate a typical minimum microcomputer system. At this writing the kit cost is about $ 150. [...] »
[theme : Applications Software] [author : Hansford] #Listing #Assembly
Extract : « Although this article is written from the standpoint of a MITS Altair computer, what is said here is also applicable to other systems. The original idea was simple: Using only a basic Altair (which started with 256 words of memory) and no peripherals, build a program which would match penpals according to age, vocation, and interests. It was originally experimental, written just to see if it could be done. But the program has proved so practical that we have been using it continually for our penpal club. The original program has been expanded to select compatible penpals from more than 200 choices. It has application wherever it is necessary to match data. In the version described here, a simple executive program can select the matching program as well as several other programs located elsewhere in memory. The executive reads the Altair sense switches for its inputs. [...] »
[theme : Software] [author : Gable] #OperatingSystem #HowItWorks #Algorithm
Extract : « The fundamental interface between the user and the hardware of a computer system is the system software. It runs the gamut from a dozen or so bytes of a bootstrap loader on a microcomputer to the multimillion word operating system of a large general purpose computer system. In fact, the microcomputer system can be made to do much of what the general purpose computer docs with appropriate versions of systems software. One of the most significant differences between the big computer and the microcomputer is that the large computers typically operate on multiple bytes of information and often provide extended arithmetic and logical operations. Minicomputers and microcomputers can emulate these extended operations with software; the main difference is speed. The typical large computer might execute its built in instructions 1000 times faster than a microcomputer's software emulation. [...] »
[theme : Applications] [author : Lehman] #Software #Algorithm #Finance
Extract : « Here's an outline of an accounting system suitable for small business use on a microcomputer. It is designed for a small, inexpensive system having a central processor, Teletype IO, one or preferably two cassette tapes for storage, and a high level language facility such as BASIC. It could probably be written in assembly language, but at a price of inconvenience. The system is designed to be used by an individual proprietorship (one man business) or a small partnership. While perhaps suitable as a bookkeeping system for a small corporation, it is not intended to produce the sort of reports which various regulatory agencies may require of one. [...] »
[theme : Software] [author : Herman] #Initiation #Method #Algorithm #Programming
Extract : « For a number of years now the field of computer programming has been moving from the realm of a black art to an organized and systematic process. A number of programming techniques have evolved during this change. This article will present the basics of a technique known as structured, top down programming. In the process of applying these techniques in my own work, it occurred to me that the basic concepts could be useful to those just learning to program, not to mention the veteran hackers in the crowd. If learned at an early stage, these techniques can lead to more rapid and sound development of one's programming skills. [...] »
[theme : Review] [author : Lett] #Experience #ComputerKit #Education
Extract : « In late May of 1975, John F Kennedy High School in Somers NY suddenly had to face a computational crisis. For the previous two years, the school had been given computing time gratis by the local Board of Cooperative Educational Services; our only expenses were the purchase of an acoustic coupler, and the telephone connection costs. But that May we were abruptly informed that the service would no longer be available. [...] »
[theme : System Design] [author : Suding] #ComputerKit #Tips
Extract : « Even a casual glance through the BYTE, Radio Electronics, Popular Electronics, etc, advertisements and articles reveals a growing proliferation of microprocessor integrated circuits and completed units. Which of these is right for you? Here are some ideas to bear in mind while making your choice.
Why do you want a processor at all? Reasons vary greatly. Many find themselves intrigued by the "computer environment" around us, and the microprocessor has become a low cost entry point into "computers." [...] »
[theme : Hardware] [author : Nelson] #Review #ComputerKit #Microprocessor #Simulation
Extract : « When using programmed IO transfers, one must live with a delay waiting for the usually slow peripheral device to get ready to receive or transmit data. Often this requires the CPU to traverse a "waiting loop" thousands of times between transfers. Interrupt-initiated transfers eliminate this wasted time by allowing the peripheral device to initiate each data transfer, rather than the program. Between individual transfers the CPU is free to go about its business executing the main program. This is accomplished by isolating the IO handling routines from the mainline program and using the interrupt system to ensure that these routines are entered only when an IO device-ready flag is set, indicating that the device is actually ready to perform the next data transfer. [...] »
[theme : Hardware] [author : Zarrella] #HowItWorks #Memory #Algorithm
Extract : « An address is an identifier which describes the location of a particular piece of information within a computer's memory system. This information, when presented to the central processing unit for use in a computation, is usually referred to as an operand. In all microprocessor systems and in most other computer systems, an address is a binary number which is decoded to reference one computer word of information somewhere in the memory subsystem. Figure 1 illustrates how unique addresses are typically associated with memory cells. [...] »
[theme : Product Description] [author : Wadsworth-Arnold] #BASIC
Extract : « Here is a new product description of the SCELBAL language, supplied by its authors, Nat Wadsworth and Mark Arnold of Scelbi Computer Consulting, Inc, 1322 Rear-Boston Post Rd, Milford CT 06460. Scelbi's philosophy of software provides an excellent model of a fully supported product: The firm supplies a completely documented package including user level documentation, detailed listing and program design information. By providing such complete detail, this type of product becomes an excellent package for both the novice and advanced programmer. The novice can begin with the user level documentation, using the package; the advanced programmer can use the detail design information to customize and enhance the package to suit personal tastes. [...] »
#Interface #Standard
#Display #Graphics
Extract : « Imagine being able to look inside your computer memory, actually being able to see the individual bits. With this sort of X ray vision your computer memory could also serve as your computer display. Messages could be spelled out by lighting some bits and darkening others. Games could be played with clusters of bits forming game pieces and markers. Space War might be played with miniature rocket ship patterns zooming in, out and around the visible region of memory address space. The key element of hardware required to actually achieve this imagined result is a memory module which has provisions to map its contents onto a television screen. This is precisely what Cromemco has clone in creating its TV Dazzler product, the results of which were used to create this month's cover. [...] »
#Book
Extract : « Computer Chess by Monroe Newborn, Academic Press, Inc, New York, 1975. $15. (Published under the auspices of the Association for Computing Machinery Inc.) [...]
The Best of Creating Computing - Volume 1 , David H Ahl (editor), Creative Computing Press, Morristown N] 07960; 1976; 8-1/2 x 11, 328 pages. Paper $8. 95. [...] »
#Association
#Listing #Assembly