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Ohio Scientific Challenger C4P-MF

See below for specifications and information on this system.

Specifications and information

Introduced: October 1979
Original Price: $698 for C4P with 8K RAM, 8K ROM, cassette storage
$1695 for C4P-MF (MiniFloppy) with 24K RAM, no ROM
CPU: 6502 (6502C, known as the "GT Option", for an additional $950)
Memory: 24K RAM expandable to 48K
Display Capability: TV video output, 256x512 resolution, up to 16 colors
Operating System: BASIC in ROM for cassette version, BASIC on disk for MF version
OSI OS-65D disk operating system
Input/Output: 53-Key Keyboard
Programmable audio tone generator, 200 to 20kHz, 8-bit DAC
Audio cassette interface (cassette version only)
Joystick interface
X-10 home security system interface
Modem interface
Parallel interface
Bus: OSI bus
Other Items in Collection: N/A
Items Needed Operating System Diskettes, Documentation, Accessories

The OSI Challenger C4P is a 6502-based computer much along the lines of the Apple II, but with much greater built-in interface capability. It follows the original Challenger C1P, circa 1977.

Unfortunately for the C4P, Apple had introduced the Apple II Plus back in June of 1979, nearly four months before the C4P hit the market. Although the C4P models were cheaper and more capable (the Apple II+ sold for $1195 with 48K and no disk drive), the lack of a standardized expansion bus was OSI's achilles heel. A flood of third-party expansion cards for the Apple II bus led to the downfall of the C4P, although OSI would soldier on till 1981 making more business oriented systems. OSI was sold to "M/A-Com" in March of '81, and the OSI name was retired a year later.

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