Hewlett-Packard 9100B Desktop Electronic Calculator

This programmable desktop electronic scientific calculator has a beige metal case, a cathode ray tube display, a keyboard with four groups of keys, and a slot for a magnetic program card. The leftmost set of 15 tan keys includes coordinate conversion, logarithmic, exponential, trigonometric, and absolute value function keys. A switch above it can be set at degrees or radians.
The set of 15 ivory and dark brown keys second from the left allows for the positioning and storage of numbers in different registers. Next to the right is a set of 20 brown and ivory keys to enter numbers and to specify machine functions. The rightmost set of 14 tan keys is used for programming.
Five hand-wound circuit boards are inside the case, and three smaller circuit boards are inside the lid. There is a white power cord. A sticker on the back of the machine reads: SERIAL NUMBER (/) 938-02147.
The Crocker Nuclear Laboratory of the University of California at Davis acquired this machine in May of 1970 for a price of $5,195.00. Funds came from the Atomic Energy Commission’s Experimental Nuclear Physics program.
For related prototypes, see the green machine of Thomas Osborne (198.0311.01, 1978.0311.02) and the prototype HP9100A (1978.0311.03).
Accession File.
Currently not on view
Object Name
electronic calculator
date made
date received
Hewlett-Packard Company
Physical Description
metal (overall material)
plastic (overall material)
glass (overall material)
paper (overall material)
overall: 21.5 cm x 40 cm x 49 cm; 8 15/32 in x 15 3/4 in x 19 9/32 in
place made
United States: Colorado, Loveland
ID Number
accession number
catalog number
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


"It's easy to forget or even believe that the computer is only a adding machine which can add 1 + 1, 1 + 0 and 0 + 0. But, of course it can add those two numbers so fast it's really amazing and even this old relic has processing power faster than most human minds can comprehend. It's very interesting to me that the registers and ALU still resemble chip sets and ALUs of modern computers."

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