Mechanical Computer - Electro-mechanical Computers

Electro-mechanical Computers

Early electrically powered computers constructed from switches and relays rather than vacuum tubes (thermionic valves) or transistors (from which later electronic computers were constructed) are classified as electro-mechanical computers. Examples include:

• Z2, 1939
• Z3, 1941 – Designed by Konrad Zuse.
• Harvard Mark I, 1944 – Built by IBM. ("electro-mechanical counters")
• Harvard Mark II, 1947 ("electromagnetic relays")
• "Binary Arithmetic Relay Calculator" BARK, 1950
• Simon (computer), 1950
• University of Toronto Electronic Computer (UTEC), 1951
• "Binary Electronic Sequence Calculator" BESK, 1953
• "Harry Porter's Relay Computer", 2005