Atanasoff-Berry Computer
More info
- Creator
- John Vincent Atanasoff and Clifford Berry, Iowa State College
- Released
- 1942
- Type
- Electronic calculating machine
The first electronic digital computing device, built in an Iowa basement, scrapped in 1948 by people who did not know what it was, and vindicated by a federal court in 1973.
Physics professor John Atanasoff and his graduate student Clifford Berry built the machine between 1937 and 1942 to solve systems of up to 29 simultaneous linear equations, a common and unbearable chore in physics. Three of its choices became standard practice: binary arithmetic, vacuum tubes as the computing element, and memory kept separate from the arithmetic unit. That memory was capacitors on a rotating drum, read and rewritten each revolution — the same refresh idea DRAM uses now.
It was not programmable. The machine did one thing, and intermediate results were burned onto punch cards by a spark writer that failed about once in a hundred thousand attempts, a fault Atanasoff never got round to fixing. He was called up for war work in 1942, and in 1948 the machine was dismantled by staff who had no idea what was in the basement.
John Mauchly visited Atanasoff in June 1941 and spent five days studying it. That mattered thirty years later: in Honeywell v. Sperry Rand, Judge Earl Larson invalidated the ENIAC patent in 1973, finding that Eckert and Mauchly had not themselves invented the automatic electronic digital computer but derived it from Atanasoff. The ruling attracted almost no attention — it landed the same week Nixon fired the Watergate special prosecutor.