ENIAC: Celebrating Penn Engineering History

The Inventors: John W. Mauchly and J. Presper Eckert, Jr.

John W. MauchlyThe operators of the Differential Analyser - the team of women dubbed "human computors" and who were recruited and trained to run ballistics calculations for the war effort, were not the only ones working under top secret conditions at The Moore School.

During the war, interest in speeding up computation was underlined by the need to be able to calculate the speed and trajectory of bombs and missiles. The government at this time funded a course taught at The Moore School called the Engineering, Science, Management War Training (ESMWT) course. It offered instruction in electronics and other subject relevant to the war effort. John Mauchly was a professor at Urisinus College when he enrolled in the course. Later, because of his outstanding performance at ESMWT, he was hired at Penn to replace professors called away to active duty. J. Presper EckertIt was during this time that Mauchly met J. Presper Eckert, who was a graduate of Penn and hired to run the laboratory for the ESMWT course.

Both men were keenly interested in speeding up the ability to perform computations. Despite the secret staffs of women at Penn and other locations, there was a backlog of ballistics computation building up, hampering the efforts of the troops fighting abroad. After securing a contract from the military's Ballistics Research Laboratory (BRL), development of the ENIAC began.

Mauchly was very much the visionary of the ENIAC's use of mechanical and vacuum tube technologies. Eckert was the engineer of the project who solved it's technical problems. The chief challenge was tube reliability in the operation of ENIAC. Eckert was able to get good reliability by running the tubes at one-quarter power. Together with a team of wiremen, programmers and draftsmen, the ENIAC was built. When it was operational, the machine was run by a team of six women.

For the next nine years, the ENIAC served as the primary computing engine for the Army.