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This article is written like a personal reflection or essay and may require cleanup. Please help improve it by rewriting it in an encyclopedic style. (December 2007) |
Ohio Scientific Inc. (also known as Ohio Scientific Instruments) was a United States computer company that built and marketed computers from the late 1970s to the early 1980s. The company was founded by Mike and Charity Cheiky in 1975 in Hiram, Ohio.[1]
One of their first products, launched in 1978 was the OSI Model 500 system, a very simple single board computer based on the MOS Technology 6502 microprocessor, but lacking a Video Display Controller. It needed an external video terminal such as the VT100, or the CT-64 terminal system from SWTPC, to create a useful system. Their later products were also 6502-based, the Superboard II, Challenger 1P, Challenger 4P and Challenger 8P, introduced in 1979 and discontinued in 1981.
Original Ohio Scientific motherboard designs used 7400-series transistor-transistor logic TTL chips. Instead of using a floppy-disk controller IC, they used the Motorola 6850 ACIA serial-port UART chip, which made their 8 and 5 inch floppies unreadable on any other system.
The company supplied full schematics of their hardware,which allowed for some field modifications such as increased clock speed, and increased video line length.
The video systems did not have color-graphics like the Apple II, just upper-case text, and some pseudo graphical characters, (comparable to the "PETSCII" character-set of the Commodore PET) for drawing lines and supporting simple games. They hadn't figured out how to write to the video memory without glitching the display, so the hardware would blank the screen for a few microseconds while it accessed the video memory. There was an add-on graphics card for the Superboard that would display 256 by 256 pixels. It came with software to draw 3D graphics.
Software was also minimal: a cassette boot loader in ROM and Microsoft BASIC in ROM. Disk-based systems included a bare-bones "Disk Operating System", which did not have file names, only disk track numbers. Users were advised to reserve track 40 as a text area for a manual disk directory. Even so, the disk was much handier than reading and writing cassettes at 1200 baud.
History
Mar 1981 OSI is sold to M/A-Com Inc. of Burlington MA. OSI will concentrate on business systems.
May 1982 OSI name is changed to M/A-Com Office Systems Inc.
References
- ^ Allan, Roy A (2001). "Transition to Microcomputers", A History of the Personal Computer. Allan Publishing. ISBN 0968910807.
External links
- Marcus Bennett's OScientific Documentation Store
- Dave's OSI repository (Note: The forum was brought to its knees by spam; work is in progress to re-establish
- Mark's OSI and Compukit archive
- Srecord program: multiplatform hex reader writer understands OS-65V hex dumps
