Howard Aiken

 

 

1900-1973. Aiken and his team at Harvard University, Cambridge, Mass. (with IBM's backing), complete the "ASCC Mark I", also called the "Harvard Mark I". This electromechanical machine is the first programmable calculator to be widely known: The machine is 51 feet long, weighs 5 tons, and incorporates 750,000 parts. It includes 72 accumulators, each incorporating its own arithmetic unit as well as a mechanical register with a capacity of 23 digits plus sign. The arithmetic is fixed-point, with a plug board setting determining the number of decimal places tape readers, and typewriters. There are 60 sets of rotary switches, each of which can be used as a constant register -- sort of a mechanical read-only memory.  The program is read from one paper tape; data can be read from the other tapes, or the card readers, or from the constant registers.