Radschool Association Newsletter

Radschool Association Newsletter - Vol 7

30 Nov 2000

Page 6

Computers and stuff

Sam Houliston

The first Personal Computer.

It seems that the personal computer that everyone takes for granted has been around for ever, but it is really only a very recent invention.

The Altair 8800 is generally accepted as the first "Personal Computer". It was designed by a bloke named Ed Roberts from a company called MITS, and was introduced in April 1974 at one of the amateur computer clubs that were formed in what is now known as Silicon Valley. It was a "build it yourself" unit with chassis, power supply, system PCB, and loaded with 256 bytes of memory. There were no I/O devices, it didn't have a monitor or a keyboard and there was no Operating System available, and you programmed the system from the front panel (octal) switches (see photo above). The Altair 8800 made its debut in an article that appeared on the cover of the December 1975 issue of Popular Electronics. Within two months the little company MITS, was struggling with thousands of orders. The computer came in kit form and required quite a bit of work and skill to assemble. Users would enter their programs in binary by flipping switches on the front panel of the machine. The output could be read in binary on the LEDs. No software was available for the little machine and users would have to write their own.

The basic unit had only 256 bytes of RAM and cost $395. This configuration made the little machine virtually useless for any real problem solving. However it was designed to be expandable with a bus that allowed plug in cards. The bus was to set the standard for the next 5 years. Within months expansion boards were available to add more memory and attach terminals or teleprinters. One of the most popular peripherals was the Teletype corporation’s ASR-33 teletype. This provided a printer, keyboard, and storage device (paper tape). This first desktop computer spawned the idea that computers could be built small and developed without the resources of IBM, Univac, Burroughs and the other mega powers of the computer business at that time.

The first IBM "clone" PC.

The first true IBM bus compatible "clone" personal computer was the MPC introduced by Columbia Data Systems in June of 1982. There had been several MS-DOS compatible personals up to that time that ran DOS programs but they had proprietary busses or designs that limited their broad acceptance.

Columbia shipped the first hard drive based systems (5MB formatted capacity) before IBM did. Their controller was not compatible with the controller that IBM shipped later and Columbia quickly responded with a (mostly) IBM compatible replacement.

If you use Microsoft’s Excel 97, you might want to try this little experiment. (Only works with ‘97)
Open a new worksheet.
Press the F5 key (Go to).
Type X97:L97 (all in caps).
Click Ok.
Press Tab once.
While holding down the Ctrl and Shift keys, click the Chart Wizard button on the tool bar. Use your mouse to control movement-great eh!!

Firsts.

The first electronic spreadsheet written for the personal computer was VisiCalc. The first popular word processor for micro-computers was Electric Pencil. It was available in December 1976. The first integrated circuit was produced by Texas Instruments in Sep 1958. Prior to this development in electronic circuits consisted of resistors, capacitors, transistors and wiring/etches. Each component was manufactured separately by different processes and integrated into an electronic circuit on a PCB using wiring/etches and solder connections to create a working circuit. Jack Kilby came up with the idea of creating an "integrated circuit" using a silicon wafer. By adding impurities to the silicon they could create resistance, capacitance, transistor junctions and conductive paths on a single silicon "chip". This IC would be a self contained circuit with no external wiring or solder connections.

The first handheld calculator using IC's was produced by Texas Instruments in 1967. It performed the 4 basic functions of the calculators of those days add, sub, mul, div.

While working for IBM in the late 1960's, Alan Shugart is generally regarded as the inventor of the floppy drive He later founded Shugart Associates to design and manufacture floppy drives. (This info was pinched from the web)

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