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Uploaded on Oct 7, 2014
Recorded: May 8, 1980
George Stibitz developed early relay-based calculators and devices at Bell Labs starting in the 1930s. Stibitz begins by discussing early mechanical calculation methods, from Pascal and Babbage, to the work of Howard Aiken on the Mark I. Stibitz discusses his work with relays and binary representation. Stibitz demonstrates his Model K adder reproduction, built of household items and a pair of borrowed relays. Stibitz's Complex Number Calculator (CNC), built in 1938, was designed to assist with arithmetic problems requiring more precision than could be obtained by the human “computers” at the lab. The CNC was demonstrated remotely from New Jersey to a conference at Dartmouth College in Hanover, New Hampshire. Stibitz details the process of using the system, the difficulties with using relays and paper tape, the work required of operators, and follow-on devices. The lecture concludes with questions from the audience.