J. Presper Eckert (the man in the foreground turning a knob) served and John Mauchly (center) designed ENIAC to calculate the trajectory of artillery shells. The machine didn't debut until February 1946, after the end of World War II, but it did launch the computer revolution.
ENIAC contained nearly 18,000 vacuum tubes and filled a 1,500-square-foot room. To program it, different accumulators had to be wired to each other.
A power-hungry beast, ENIAC ran on 170,000 watts. But contrary to rumor, the lights in Philadelphia did not dim when it ran.
Mauchly and one of ENIAC's programmers. After a disagreement with the University of Pennsylvania over patents, Mauchly and Eckert left to form the Eckert-Mauchly Computer, which was bought a few years later by Sperry Rand and later became Unisys. Although Eckert stayed on, Mauchly left and was nearly broke when he died in 1980.
"The audience was absolutely astounded. ENIAC ran the trajectory faster than it took the bullet to trace it. People got, as a souvenir, a printout of the trajectory we ran," said Jean Bartik, one of the surviving programmers, about the first demonstration of ENIAC to the military and other scientists.
Herman Goldstine, a mathematician from the U.S. Army, at right and Eckert. Although the two collaborated on ENIAC, many of the original participants argued later over who deserved credit. Goldstine was responsible for bringing John Von Neumann into the ENIAC project. Eckert later asserted that Von Neumann tried to take credit for ideas that emerged with Eckert and Mauchly.
Iowa State professor John Atanasoff liked fast cars and scotch, according to interviews he gave. After driving to a bar in Illinois, he had a few drinks and sketched out on a napkin a concept out for an electronic device that could perform math functions with signals from vacuum tubes. The ABC Computer was built in 1941. It could perform multiplication, but worked stopped on the project after the attack on Pearl Harbor and Atanasoff never returned to it.
Did Mauchly steal ideas from the Atanasoff? He visited Atanasoff and the two discussed computers before ENIAC was built. Mauchly defenders, however, say ABC just confirmed his own ideas and ENIAC used a far different architecture. A court, however, invalidated the ENIAC patents. Still, ABC was never used on any real computing projects.