Imsai VDP-80

[Vin112]

The IMSAI VDP-80, released in 1977, was a pioneering all-in-one microcomputer notable for integrating a 3 MHz Intel 8085 processor, 32K or 64K RAM, dual 8-inch floppy drives, a 12-inch video display, and a full alphanumeric keyboard with advanced features like N-key rollove all within a single desktop cabinet. Its claim to fame was being among the first microcomputers shipped fully assembled and ready to use, targeting small businesses and professional users at a time when most systems were sold as kits, and it came bundled with IMDOS (an enhanced CP/M variant) and BASIC, making it a turnkey solution for data processing and business applications. Although technologically advanced, the VDP-80 (Video Display Processor) was expensive and heavy, and its popularity was limited compared to emerging competitors like the Apple II and TRS-80; IMSAI’s bankruptcy in 1979 marked the end of its brief prominence.

Manufacturer: IMS Associates, Inc., later known as IMSAI Manufacturing Corp, based in San Leandro, California
Type: All-in-one desktop computer
Release Date: 1977
Cost at release: USD $6,995 (CAD ~$36,000 adjusted for inflation)
MIPS: 0.3 (300 KIPS)

Hardware Specifications

CPU: Intel 8085 microprocessor, 3 MHz
RAM: 32K or 64K RAM (expandable)
Storage: Dual 8-inch PerSci floppy disk drives (double density)
Display: 12-inch CRT video display 80 columns × 24 lines
Keyboard: Integrated alphanumeric 62-key main keyboard
7-slot motherboard for expansion
Serial and parallel I/O ports (printer/modem support)
Heavy-duty power supply
Built-in IMDOS operating system (CP/M variant), with BASIC and FORTRAN IV support
Fully assembled desktop cabinet
Weight: 46 kg (103 lbs)

Operating System & Programming Languages

OS: IMDOS, a multi-disk operating system that was IMSAI’s enhanced and customized version of CP/M, supplied with every system
Programming Languages: BASIC (interactive and compiler versions, such as BASIC-E and CBASIC), FORTRAN IV (Level 2 ANSI compiler), Assembly language (8085 assembler and dynamic software debugging tools), Additional utilities for software development and diagnostics were included with IMDOS

Notables

It was one of the first fully assembled, turnkey microcomputers aimed at business and professional users, integrating CPU, RAM, dual 8-inch floppy drives, a 12-inch CRT, and a sophisticated keyboard in a single desktop cabinet.
The VDP-80’s CPU was the Intel 8085 which was Intel’s second generation of CPU’s; in 2025 Intel has released it’s 15th generation CPU
The IMSAI VDP-80 could dynamically switch its floppy disk controller between single and double density to support multiple IBM disk formats simultaneously, a rare feature for its time.
The VDP-80 could serve as an intelligent terminal for distributed data processing or as a standalone business computer, making it versatile for both local and remote computing tasks.
The VDP-80 was sometimes called a “Video Data Processor,” highlighting its integrated display and data processing focus.
Despite its technical strengths, the VDP-80 sold poorly due to its high price and heavy weight, and it was quickly outpaced by more affordable and user-friendly competitors like the Apple II and TRS-80.
IMSAI as a brand is legendary in the vintage computing world because the earlier IMSAI 8080 was the first major “clone” of the Altair 8800, helping to establish the S-100 bus as a microcomputer standard and making personal computing more accessible.
The IMSAI 8080 famously appeared in the movie “WarGames” (1983), cementing its place in pop culture and inspiring a generation of computer enthusiasts.
IMSAI’s pioneering use of CP/M (and later IMDOS) contributed to CP/M’s rise as the de facto standard operating system for early microcomputers
There is a lot of IMSAI lore and apparently management found the cases for this computer in bulk for a discounted rate and the Engineers had to make them work for this all-in-one design. The case had so little air flow that many systems overheated and broke – yikes.

Donated by: Dr. Arlen Michaels

Vintage Computing Collection