Evolution of IMSAI 8080, which was evolution of Altair 8800 kind of. Was based on Intel 8085, instead of Intel 8080 as previous IMSAI Many variants sold. Quote: For example, the VDP-40 had two 5-1/4" disk drives, a 9" 40-character-wide display and a 2K ROM monitor all in one cabinet. The built-in keyboard had a 8035 microprocessor and a serial interface to the main board. The VIO-C video board had 2K firmware ROM, 2K character generator read-only memory (ROM) with 256 characters and 2K of refresh memory.