ENIAC
In 1942 Mauchly wrote a memo proposing the building of a general-purpose electronic computer. The proposal, which circulated within the Moore School (but the significance of which was not immediately recognized), emphasized the enormous speed advantage that could be gained by using digital electronics with no moving parts. Lieutenant Herman Goldstine, who was the liaison between the United States Army and Moore School, picked up on the idea and asked Mauchly to write a formal proposal. In April 1943, the Army contracted with the Moore School to build the Electronic Numerical Integrator and Computer (ENIAC). Mauchly led the conceptual design while Eckert led the hardware engineering on ENIAC. A number of other talented engineers contributed to the confidential "Project PX".
Because of its high-speed calculations, ENIAC could solve problems that were previously unsolvable. It was roughly a thousand times faster than the existing technology. It could add 5,000 numbers or do 357 10-digit multiplications in one second.
ENIAC could be programmed to perform sequences and loops of addition, subtraction, multiplication, division, square-root, input/output functions, and conditional branches. Programming was initially accomplished with patch cords and switches, and reprogramming took days. It was redesigned in 1948 to allow the use of stored programs with some loss in speed.
In 2002, for his work on ENIAC he was inducted, posthumously, into the National Inventors Hall of Fame.
Read more about this topic: John Mauchly