Xerox 820


The Xerox 820 is an 8-bit desktop computer sold by Xerox in the early 1980s. The computer runs under the CP/M operating system and uses floppy disk drives for mass storage. The microprocessor board is a licensed variant of the Big Board computer.

Xerox introduced the 820 in June 1981 for $2,995 with two ​5 14-inch single-density disk

drives with 81K of capacity per diskette, or $3,795 with two 8-inch drives with 241K capacity. To beat the IBM PC to market Xerox created little of the computer's design; it is based on the Ferguson Big Board computer kit and other off-the-shelf components,[1][2] including a Zilog Z80 processor clocked at 2.5 MHz, and 64 kiB of RAM.[1] Xerox chose CP/M as its operating system because of the large software library[3]—The 820 is compatible with all Big Board software[4]—and sold a customized version of WordStar for $495, although by 1982 the company offered the standard version for the same price.