Archive for the ‘Desktop Computing’ Category

IMSAI 8080

The IMSAI 8080 was arguably the first personal computer clone!

Closeup view of the IMSAI 8080

Closeup view of the IMSAI 8080

With the large and growing success of the MITS Altair 8800 early in 1975, IMS Associates, Inc. of San Leandro, California was able to capitalize on its success with an improved copy. Like the Altair computer, the IMSAI utilized the S-100 bus, Intel 8080 microprocessor and a front panel with LEDs and switches. You could utilize the switches to read and write to memory locations, single step the CPU, or even stop it. The LEDs would blink according to the values inside the address and data buses. The IMSAI 8080 could run all of the same programming instructions, and later software, when it became available. IMS Associates improved just about every aspect of the Altair’s design, with a higher specification power supply, an anodized aluminum chassis, more S-100 expansion slots and a better front panel with superior paddle switches.

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Processor Technology Sol

Sol-20 with it's distinctive blue color and wooden sides

Sol-20 with its distinctive blue color and wooden sides

The Altair, the IMSAI, and then later, many other microcomputers created a cottage industry. MITS and IMS Associates only offered a limited number of products and upgrades, if you could get them given the high demand for them at the time. Gary Ingram and Bob Marsh, two friends in Berkeley, California, saw this as a business opportunity. Marsh, an active member of the Homebrew Computer Club, would hear complaints about the Altair at every club meeting, so with Ingram, they decided to form a company called Processor Technology Inc. Their first product was a reliable, static 4 kB memory board for the Altair, as they knew that MITS was producing an unreliable dynamic version. Processor Technology’s 4KRA RAM board became an almost instant hit and launched the company into a thriving business. Ingram and Marsh were then able to move out of their garage workshop and into a large industrial facility.

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Altair 8800

Altair 8800

Altair 8800

The Altair 8800 from MITS (Micro Instrumentation Telemetry Systems) was the “World’s first personal computer.” That is, the world’s first commercially successful, mass-produced personal computer. It established creator Ed Roberts as the “Father of the microcomputer” and Albuquerque, New Mexico as its birthplace. There were a few other earlier machines available in very limited numbers, but none of them came as a complete kit or fully assembled and tested as the Altair was.

Ed was one of the co-founders of MITS, along with key employee Forrest M. Mims III. The company was originally formed to sell electronic kits for model rockets. Later Ed bought out two other partners when he decided to go into the calculator kit market and they didn’t. By 1973, MITS sold over $1 million in calculators a year, but by mid-1974, competition from the Japanese with cheap calculators had the company in over $300,000 of debt. MITS needed another key product. There was a project rivalry between Radio-Electronics magazine and Popular Electronics, and R-E had published an article on a computer kit called the Intel 8008 processor based “Mark-8.” Ed decided that his company would create a computer based on the more power Intel 8080 and have it ready for a January 1975 issue of PE.

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