Keyboard for Green Machine Prototype Electronic Calculator

As a graduate student in electrical engineering at the University of California at Berkeley, Thomas E. Osborne began thinking about the design of a desktop electronic calculator suited for calculating the very large and very small numbers encountered in scientific work. In January of 1964, he formed the firm Logic Design, Inc., to develop his ideas. By late 1964, he had built this prototype keyboard and display, as well as a prototype logic unit (1978.0311.02).
The keys are of plastic, the case of balsa wood painted green. The prototype is known as “the green machine” from the color of the paint.
The model has an array of nine digit keys on the right front, with zero, decimal point and exp keys above them. On the left are twelve keys for arithmetic operations, clearance, and memory access. After damage to the case, it was reconstructed by Osborne before it came to the Museum.
For related objects, see 1978.0311.02. For related documentation, see invention notebooks and photographs by Osborne (1978.0311.03 through 1978.0311.14). For purchase orders of components used in the prototype, see 1985.0264.01. Elements of the green machine were incorporated in Hewlett Packard’s first commercial electronic calculator, the HP9100. For a prototype of that machine, see 1978.0311.03.
Bernard M. Oliver, “How the Model 9100A Was Developed,” Hewlett-Packard Journal, September, 1968. A copy of this article is at the HP Museum website.
The website of the University of Wyoming contains biographical information about Osborne.
Currently not on view
date made
date received
Osborne, Thomas E.
place made
United States: California, Berkeley
Physical Description
balsa wood (case material)
plastic (keys material)
overall: 16.5 cm x 21.5 cm x 40 cm; 6 1/2 in x 8 15/32 in x 15 3/4 in
ID Number
catalog number
accession number
Credit Line
Hewlett-Packard Company
See more items in
Medicine and Science: Computers
Desktop Electronic Calculators
Computers & Business Machines
Data Source
National Museum of American History, Kenneth E. Behring Center


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