Hewitt Crane

Hewitt D. Crane (1927, Jersey City, New Jersey — June 17, 2008, Portola Valley, California) was an American engineer best known for his pioneering work at SRI International on ERMA (Electronic Recording Machine, Accounting), for Bank of America; magnetic digital logic; neuristor logic; the development of an eye-movement tracking device; and a pen-input device for computers.

After a stint in the U.S. Navy as a radar technician, he worked as a computer maintenance technician for IBM (1949-1952), followed by working on digital computer design at the Institute for Advanced Study at Princeton University, under the leadership of John von Neumann. He then developed magnetic multiaperture devices (MADs) at RCA Laboratories (now Sarnoff Corporation). In order to develop magnetic logic, Crane controlled the direction of bit flow in magnetic ferrite memory cores. Ferrite logic circuits are inherently more stable than vacuum tubes and transistors, draw no power when unused, and are impervious to electromagnetic interference. In 1959, Crane introduced the all-magnetic logic approach at the Fall Joint Computer Conference, eventually leading to a demonstration of the world's first all-magnetic computer in 1961. The technology was soon commercialized by AMPEX, under license from SRI, and used primarily in the rapid transit system of New York city and at railroad switching yards, where electro-magnetic interference made electronic computers unfeasible. The development and growth of planar transistors in silicon chips and integrated circuits displaced magnetic core logic, although it may still be useful for extended space missions and other extreme conditions, but using integrated circuit manufacturing techniques (e.g. etching and deposition of a substrate, and not an assembly of discrete magnetic cores). The prototype of the first all-magnetic computer now resides at the Computer History Museum, in Mountain View, California.

Douglas Engelbart worked with Crane on magnetic logic devices, early in their careers, before Engelbart moved on to work on hypermedia and augmenting the human intellect with computers, and before Crane began research on replicating human functions with digital computers. In addition to his engineering work at SRI, Crane cofounded Communication Intelligence Corporation, to commercialize computer-based handwriting recognition on graphics tablets.

Crane's last intellectual effort was a manuscript on issues related to energy development, carried out in collaboration with SRI-International colleagues: Ed Kinderman, and Ripudaman Malhotra.

Crane died at the age of 81 on June 17, 2008 at his home in California.