Electro-mechanical computers

first working programmable, fully automatic digital computer

early American computer

computer

thumb|220px|A wartime picture of a Bletchley Park Bombe

computer

mechanical analogue computer designed to solve differential equations by integration

Early British computer

computer only built from mechanical components such as levers and gears

IBM Selective Sequence Electronic Calculator

electromechanical computer at Harvard University, completed in 1947

The Nimatron was an electro-mechanical machine that played Nim. It was first exhibited in April–October 1940 by the Westinghouse Electric Corporation at the 1939-1940 New York World's Fair to entertain fair-goers. Conceived of some months prior by Edward Condon and built by Gerald L. Tawney and Willard A. Derr, the device was a non-programmable digital computer composed of electro-mechanical relays which could respond to players' choices in the game in a dozen different patterns. The machine, which weighed over a metric ton, displayed four lines of seven light bulbs both in front of the player

piece of naval technology

extremely limited computer released in 1950, intended as an educational demonstration of the concepts behind digital computers

early Swedish relay computer