• Commodore Free Magazine, Issue 75 - Part 6

    From Stephen Walsh@39:901/280 to All on Thu Dec 12 11:07:20 2013
    NDUSTRY PROLOGUE -

    By 1963, transistors had replaced vacuum tubes, and the industry had settled into a form of stability. Although there were a number of computer manufacturers, IBM enjoyed over two thirds of the market. Industry watchers often referred to "IBM and the Seven Dwarfs."

    Why did IBM dominate? In part, it was because they had been in the data processing business long before the arrival of computers. Using Hollerith punched cards, IBM had an array of "unit record" equipment such as keypunch devices, tabulators, and sorters; they had decades of experience in handling data.

    A second reason for IBM's strength was that they leased their equipment rather than selling it. And with the lease came support, with system engineers on
    site or on call. Industry people talked about being sheltered by the "IBM umbrella." And, as a general rule, software was free. Assemblers, compilers, generators ... phone your IBM rep and he'd send over a copy. Need personnel training? IBM would do it free. Or, at least, at no extra charge.

    III. UNDERGROUND FUN -

    Even in those days, computer programmers and operators would have secret amusements. Secret, because senior management would have misgivings about 'horsing around' on a multi-million dollar computer. Pictures were drawn on
    the line printer, patterns generated on punched card or paper tape, games were created and played, jokes were being played on co-workers, and music was being played on these computers. Note how the word PLAY seems to be repeated.

    The seemingly impossible job of playing music on computers that had no
    speakers was accomplished in several ways. The hammers of line printers could be carefully timed to produce sounds of a selected pitch; the paper advance chain could be declutched and made to furnish drum rhythms, and a transistor radio placed adjacent to the CPU, where it would pick up the electromagnetic emissions, and would play a selection of popular numbers.

    IV. TRANSITIONS -

    In the time frame between 1963 and 1971, there were a number of changes that helped shape the nature of microcomputers to come.

    Minicomputers started to gain acceptance in 1965 with the Digital Equipment Corporation PDP-8. These "minis" were stripped down computers, designed to
    sell for a paltry $10,000 or so. In the early days, magnetic core memory was a major cost impediment, and attempts were made to circumvent it with other resources. I recall that the PDP-8 used a serial memory (a mercury column
    delay line). It was said that if you stamped the floor, you could change its memory contents. Minicomputer technology didn't have much effect on future microcomputers, but it's interesting to note that a powerful user group,
    DECUS, grew around the PDF series, and may have been a precursor to microcomputer users groups that appeared much later.

    In 1965, General Electric introduced "Time Sharing" service, where users could concurrently make use of a central computer. The terminal device was usually a Teletype (TM) machine. The major impact of time sharing on the future microcomputers was its choice of language: Basic, both adored and vilified.

    By 1971, the expensive and labour-intensive magnetic core memory that had been the heart of computers started to be replaced by semiconductor memory. This
    set the stage for on-going price reductions, which we still see today.

    This, in turn, spawned another product that was to become important in the future microcomputer world: The Floppy Disk. Magnetic core memory had been non-volatile. Once loaded, it kept its contents even when power was off. Semiconductor memory needed to be reloaded, and the 8-ince floppy disk was created by IBM for this purposed. Initially, it was a read-only device, whose contents would be created at the IBM production facility

    V. EMERGENCE OF LSI: VIATRON (1970), THEN INTEL (1971) -

    As fabrication techniques were advanced, more and more elements could be
    packed onto an integrated circuit chip. The first chips were flip-flops and gates. Then came larger assemblies such as shift registers and ALUs (arithmetic/logic units). Inevitably, a complete CPU (Central Processing Unit) would be placed onto a single chip. With a collection of chips such as CPU, memory, input/output, and some sort of control logic in a ROM (Read Only Memory), a complete computer system could be put together.

    The first microcomputer that I know of was made in 1970 by an almost forgotten company called Viatron. Viatron's main marketing thrust was terminal devices
    as inexpensive substitutes for Teletype, N machines, which were priced in the $1,000 to $1,5000 region. Viatron's concept and design was good, and they advertised massively in Datamation magazine. But their fabrication plant had poor chip yields, and eventually they disappeared from the scene. The Viatron era called for some technical innovation. CRT display devices were rare and generally costly; modestly priced printers were virtually unknown. Viatron's use of a converted television displays and "printing robots" seems quaint today.

    Intel entered the microcomputer field in 1971 with the 4004. It seems almost
    as if Intel wasn't planning this as a product; they needed to find a quick way to fulfil their contract to build a calculator for a Japanese firm, and devising and programming a microcomputer seemed to be the quickest method, but once the 4004 had been devised, the electronics industry accepted it quickly
    as a general purpose component which replaced wiring with code. Motorola announced their 6800 chip very quickly.

    VI. THE EMERGENCE OF "HOBBY" MICROS; EARLY USERS GROUPS -

    There was a rush to build. Even before computers were offered in kit form, hobbyist were salvaging parts and building logic devices. A friend of mine, Juilen Dube, salvaged some magnetic core memory from a telecommunications
    relay device, and restrung the little ferromagnetic doughnuts into a working memory, with a view to creating a small computer of his own design.

    Kits came on the market from various small entrepreneurs. Electronic houses produced their own versions, which consisted of a circuit board and a bunch of chips loose in a plastic bag. Sometimes the supplied circuit boards had
    printed circuit connections; other time you were expected to make the connections yourself using wire wrap techniques (rarely soldering). Sometimes the parts worked, sometimes they were defective, and sometimes incorrect
    wiring would wreck the chip. A saying of the times was, "All computer chips
    are powered by smoke; if the smoke gets out, the chip will fail."

    When the December 1975 issue of Popular Electronics described the Altair 8800 computer, available in kit form for about $500, the computer hobbyist world took off. The Apple I was also a kit that you needed to assemble yourself. The founders of Apple - Wozniak and Jobs - liked the new, inexpensive 6502 chip, and designed their system around it.

    Users started to get together and swap notes. In the Toronto area, TRACE (Toronto Regional Association Of Computer Enthusiasts) was under way in early 1976. An amazing assortment of machines was under construction. Some like the Intel 4004 or 8008, some the Motorola 6800. Memory was whatever came to hand, seldom more than 256 bytes. And input/output ... paper tape, toggle switches, home-brew keyboards, LED or LCD character or numeric displays, arrays of LED lights. Whatever you could get your hands on, or afford. There was little commonality between one home brew machine and the next.

    Oddly, few of the builders had any idea of what to do with the computer once
    it was complete. This may have been due, in part, to the shortage of programming skills: and lack of standardization across the assortment of machines also posed difficulties in conceptualization. In 1977 and 1978, the Ontario Science Centre invited TRACE members to display their home computers
    to the public. One member's computer controlled a model train set; another played simple logic games; one played simple music tunes. And I believe a couple just sat there, perhaps blinked lights, and looked pretty.

    VII. THE STRUGGLE FOR STANDARDS -

    There was

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