ENIAC stands for “Electronic Numerical Integrator and Computer.” It was one of the first all-purpose, all-electronic digital computers. This room-sized computer was built by the physicist John William Mauchly (Aug. 30, 1907 - Jan. 8, 1980) and the electrical engineer John Presper Eckert, Jr. (April 9, 1919 - June 3, 1995) at the University of Pennsylvania. They completed the machine in November, 1945.
ENIAC was the result of a secret US military project aimed at helping win World War 2. ENIAC filled a 30 foot x 50 foot basement room; it was made up of 17, 468 vacuum tubes, 70,000 electrical resistors, 10,000 capacitors, and many other parts. This early computer could add about 5,000 numbers each second (which was astounding at the time). ENIAC could not store programming information; it could run only one wired-in program at a time - to run a different program, the machine had to be re-wired. The mathematician John von Neumann (Dec. 28, 1903 - Feb. 8, 1957) used ENIAC to solve complicated partial differential equations in order to help his work on atomic weapons at Los Alamos National Laboratory, New Mexico, USA.
ENIAC is still located at the University of Pennsylvania, where it can be seen by special arrangement.