Ferguson Big Board

The Big Board (1980) and Big Board II (1982) were Z80 based single-board computers designed by Jim Ferguson. They provided a complete CP/M compatible computer system on a single printed circuit board, including CPU, memory, disk drive interface, keyboard and video monitor interface. The printed circuit board was sized so as to allow attachment to an 8 inch floppy disk drive. The Big Board II added a hard disk drive interface, enhancements to system speed (4 MHz vs. 2.5 MHz) and enhancements to the terminal interface.[2]

One version of the Big Board was used in the Xerox 820.

Big Board I

    • Z80 CPU at 2.5 MHz.
    • 64 KB dynamic RAM in 32 4116s or equivalent.
    • An ASCII keyboard interface.
    • A TTL / composite video CRT interface allowing a display of 24 lines by 80 characters.
    • A SS/SD floppy disk interface allowing addition of up to four 8"