The Atanasoff–Berry Computer first conceived
The Atanasoff–Berry Computer (ABC) was the world's first electronic digital computer, but it was not programmable. Conceived in 1937, the machine was designed only to solve systems of linear equations. It was successfully tested in 1942. However, its intermediate result storage mechanism, a paper card writer/reader, was unreliable, and when Atanasoff left Iowa State University for World War II assignments, work on the machine was discontinued. The ABC pioneered important elements of modern computing, including binary arithmetic and electronic switching elements, but its special-purpose nature and lack of a changeable, stored program distinguish it from modern computers.
John Vincent Atanasoff's and Clifford Berry's computer work was not widely known until it was rediscovered in the 1960s, amidst conflicting claims about the first instance of an electronic computer. At that time, the ENIAC was considered to be the first computer in the modern sense, but in 1973 a U.S. District Court invalidated the ENIAC patent and concluded that the ABC was the first "computer"
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