Electro-mechanical Computers
1940-1943

• The German engineer Konrad Zuse's Z3 (1941) was probably the first programmable computer.

• The Atanasoff-Berry Computer, built by by John Atanasoff at Iova State College, was designed to solve a complex systems of linear equations 1941.

• British Intelligence's Colossus, a built at Bletchy Park by Alan Turing (1943), was developed to decode secret messages, produced by the famous German code machine Enigma.

• In early 1943 Howard Aiken at Harward University, sponsored by IBM, completed ASCC Mark I (Automatic Sequence-Controlled Calculator Mark I), an electro-mechanical programmable computer, most similar to Z3.