The ABC Computer, made by John Vincent Atanasoff and Clifford Berry, was the first electronic digital computer. It began in 1939 and partially finished in 1942, but the computer was never completed because Atanasoff left to work for the Navy during World War II. The ABC made several advances; it used binary, was electronic instead of analog, and had a separation of memory and computing functions. The ABC could compute up to 8-digit numbers. In the summer of 1941, John Mauchly visited Atanasoff to see the ABC. Mauchly later incorperated the things that he saw in Ames, such as using electricity and vacuum tubes in computers, on the ENIAC.