Z2 (computer)

The Z2 was an electromechanical digital computer completed by the German engineer Konrad Zuse in 1940, built as the successor to his purely mechanical Z1 and reusing the Z1's mechanical memory of 64 words. Its main change was to replace the arithmetic and control logic with about 600 electrical relay circuits, which together weighed several hundred kilograms. It used 16-bit fixed-point arithmetic rather than the 22-bit floating-point format of the Z1, read its programs from punched film or card input, and ran at roughly 5 Hz, taking about 0.8 seconds for an addition. Zuse showed the machine in 1940 to members of the German aeronautical research institute DVL, today part of the DLR, and one of them, Alfred Teichmann, supported the funding of the next machine, the Z3. Photographs and plans of the Z2 were lost in Allied bombing during the Second World War, so what is known comes mainly from later descriptions.