(Or "Automatic Sequence Controlled Calculator", "ASCC") A first generation computer that was designed by Howard Aiken of Harvard University, taking inspiration from Charles Babbage's Analytical Engine. The Mark I, as the Harvard University staff called it, was built by IBM between 1939 to 1944. It was delivered to Harvard University and became operational in March 1944.
The Mark I is considered to be the first full-sized digital computer. It was built from clutches, relays, rotating shafts and switches. It read its instructions from one paper tape and data from another. It could store 72 numbers, each of 23 decimal digits. It weighed about 4500 Kg, had 800 Km of wiring, was used only for numeric calculations, and took three seconds to carry out one multiplication. The IBM archives call it the, "...industry's largest electromechanical calculator."
It was followed by the Mark II.