DEC Rainbow 100 Microcomputer


In the early 1980s, Digital Equipment Corporation (DEC) was the second largest computer company in the United States, following IBM, and was the leading producer of minicomputers. DEC had missed the initial development of personal computers, but decided to enter the market with a 16 bit machine. In 1982, it introduced the DEC Rainbow 100, for a price of $2,500.

The Rainbow 100 had both a Z-80 and an Intel 8088 microprocessor that ran at 4 MHz. It had 64 KB or RAM and 24 KB of ROM and had two built in floppy drives that could accommodate 400 KB single-sided quad density disks. It had three operating systems: MS-DOS, CP/M-86, and CP/M. Users made a selection by a menu at boot time. This portion - CPU - sat on a floor stand. For the monitor, see 1994.0078.01.2. For the keyboard, see 1994.0078.01.3. For related documentation, see 1994.3022.

The Rainbow could be used for word processing, spreadsheets, and games, although it had a monochrome screen. In addition to operating as a stand-alone computer, the Rainbow worked effectively as a VT-100 or VT-220 terminal emulator on larger machines, such as DEC's minicomputers. Although the Rainbow was a powerful and effective personal computer, it was not fully compatible with IBM systems, and eventually was overshadowed and undersold by IBM clones.

According to the donor, Steve Lubar, writing at the time he gave the machine to the museum, he "purchased the Rainbow 100 in 1984, through my wife, Lisa Thoerle,who was then an employee of Digital Equipment Corporation. There was a large employee discount, perhaps almost 50%, (if I remember right!) which made the machine affordable,and close in price to more common PCs. At the time, I was employed as a historian in the Department of History of Science and Technology,working on the Engines of Change exhibition and a variety of scholarly papers. I used the Rainbow for word processing mostly, using WordStar software, and as a VT-100 terminal, using the built-in emulation, to call bulletin boards. I always used the machine in its CP/M mode, mostly because I found that the only software I had for the MS-DOS mode (an early version of WordPerfect) was dreadful. Lisa used the machine a bit; she had a C compiler, but found the machine too slow to use to do any serious work. (She was used to VAXs and PDP-11s).

I used the Rainbow until 1988 or 1989,when I purchased a Macintosh SE.The Rainbow, it was clear by that point, was a technological deadend, too expensive to upgrade,and too idiosyncratic to take advantage of the ever-cheaper prices on hardware upgrades then available for IBM-standard PCs."


Accession File 1994.0078.

Date Made: 1982

Maker: Digital Equipment Corporation

Location: Currently not on view

See more items in: Medicine and Science: Computers, Family & Social Life, Work, Computers & Business Machines


Exhibition Location:

Credit Line: Steve Lubar

Data Source: National Museum of American History

Id Number: 1994.0078.01.1Accession Number: 1994.0078Catalog Number: 1994.0078.01.1

Object Name: microcomputer

Physical Description: plastic (overall material)metal (overall material)Measurements: overall: 66 cm x 32 cm x 45 cm; 26 in x 12 5/8 in x 17 11/16 in


Record Id: nmah_997667

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