Columns: Name | First operational | Numeral system | Computing mechanism | Programming | Turing complete
Atanasoff–Berry Computer (US) | 1942 | Binary | Electronic | Not programmable—single purpose | No | Colossus Mark 1 (UK) | February 1944 | Binary | Electronic | Program-controlled by patch cables and switches | No | Colossus Mark 2 (UK) | June 1944 | Binary | Electronic | Program-controlled by patch cables and switches | In theory (2011) | Zuse Z4 (Germany) | March 1945 | Binary floating point | Electro-mechanical | Program-controlled by punched 35mm film stock | Yes | ENIAC (US) | July 1946 | Decimal | Electronic | Program-controlled by patch cables and switches | Yes | EDSAC (UK) | May 1949 | Binary | Electronic | Stored-program in mercury delay line memory | Yes