Artifact Details


Proebsting, Robert oral history

Catalog Number





Robert Proebsting describes growing up in suburban Chicago, attending Knox College and the University of Wisconsin, graduating with a PhD in Electrical Engineering in 1967. After graduating, he went to work for Texas Instruments where he developed a MOS keyboard encoder for Microswitch and a 60 nS PMOS 256 bit static RAM. He then describes the founding of Mostek in June, 1969 and the development of their first product; a control IC for Burroughs' Panaplex display. He then describes his other early designs at Mostek, including MOS shift registers and ROMs and talks in detail about the development of Mostek's 4K DRAM, including discussions about automation of the IC mask production process, the adoption of the 16-pin package in the Mostek 4096 4K DRAM and the promotion for multiplexed addressing to save pins on the IC package. Proebsting goes on to describe the problem of other companies copying Mostek's IC designs, the traps that they put into their DRAM designs to reduce yields if they were copied, or, in the case of their single-chip calculator design, planting thirteen different traps in the design, each implemented using a different hidden layout technique. He then described the development of the 4116 16K DRAM. His discussion of Mostek ends with the buyout of the company by United Technologies in 1980 and its gradual failure to stay competitive due to mismanagement. He then describes his decision to leave in 1985 to work for Fairchild in Washington. After two years in Washington, he moved to Palo Alto to work with Fairchild's Clipper group on cache memories. When the Clipper group was sold to Intergraph, he followed the project. He finishes by describing his work as a consultant on high speed dynamic memory designs.




Hendrie, Gardner, Interviewer
Kossow, Allen, Editor
Proebsting, Robert, Interviewee


Computer History Museum

Place of Publication

Sonora, California


63 p.




semiconductor history; Mostek 4K DRAM; Multiplexed Address Pins; IC Design Protection; Mostek 4116; Fairchild Clipper

Collection Title

Oral history collection

Lot Number