OSI Superboard (I and II)

OSI Model 500 (Superboard I)

OSI Model 500 (Superboard I)

Ohio Scientific Inc. was a US based computer company that designed microcomputers from 1975 to 1981. The OSI Model 500 system was their earliest system, launched in 1977. It was a very simple single-board computer based on the MOS Technology 6502 microprocessor, but it lacked video circuitry, therefore a serial terminal had to be used. All of the computers that OSI’s went on to design used the 6502. In 1978, they released the Superboard II, also known as the Model 600. It was only available as a ready-built system, although the user had to build or buy a five volt external power supply to power it. The Superboard II included a keyboard, 4K of RAM, BASIC-in-ROM and cost just $279. OSI’s Challenger 1P and Challenger IIP-MF computers used the Superboard II as their main boards.

One thing interesting about the Superboard computers it that they only needed that 5-volt power supply to operate, and not a series of +/- 12 volts and other complicated power supply requirements like in computers that started to appear in the early 1980’s. What’s more, the OSI Model 500, now referred to as the Superboard I, didn’t have multi-pin independent I/O. It had a serial port for communications and terminal connections and a 48-pin bus system, but if you wanted to easily interface it with sensor peripherals, you had to install a 6520 CIA to do so. But at least the manufacturer conveniently provided an empty 40-pin socket to install it. The Superboard II was able to interface with cassette storage through RS-232 port.

Other interesting items to note about the Superboard II is that the board was usually ordered a few weeks in advance and arrived wrapped in aluminum foil, packaged in boxed styrofoam. It also appeared to have been hand-soldered at the factory.

Here is a video showing the Superboard II in operation

If you are interested in reading about the introduction of the Superboard from a period perspective, OSI had the Ohio Scientific’s Small Systems Journal available within the pages of the Micro 6502 Journal magazine issue 25.

The Superboard II was also fully reviewed by a new buyer in Kilobaud Microcomputing magazine back in July 1979. It’s rather interesting to read what people say about computers like this with such a fresh viewpoint.

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