By Kate Beard


By 1942, World War II was in full swing. The United States had recently entered the War in December of 1941, following Pearl Harbor. At the time, the Ordnance department was responsible for designing weapons for the Army. A particular subsection of Ordnance that focused on testing and launching ballistics was located at the Aberdeen Proving Groud in Maryland. The Ballistic Research Laboratory provided the trajectory predictions. This was a very long and complicated process, as many items influence the trajectory course of a missile, such as humidity, air pressure, angles, and the type of gun. As there were no computers, calculating the predictions by hand took twelve to twenty hours. The Ballistics Research Laboratory had a machine, the Bush Differential Analyzer, which could answer a trajectory equation in just fifteen minutes. However, it frequently broke down towards the end of a calculation, and lose all prior data. Since it was an analogue machine, each piece had to be carefully put in to place before the machine could begin. That route made progress unbearably slow, so the Ordnance department tried to discover a faster means.

The ENIAC took up an entire room

Trying to Find a Solution

The University of Pennsylvania’s Moore School of Electrical Engineering housed a better Bush Differential Analyzer than the Ballistic Research Laboratory. So in the summer of 1842, the Ordnance department signed a contract with the school, and moved their trajectory table research there. One of the professors at the Moore School, Dr. John Mauchly had a theory that one could compute the differential equations for the trajectory tables by using electronics. Along with Dr. Presper Eckert, the two presented their draft for an electronic version to the Ordnance department. Their idea was approved, and in the summer of 1943, the Moore School was formally responsible for discovering how to build an electronic numerical integrator and computer —otherwise known as ENIAC.
In charge of the project were Professor Brainerd, and the Drs. Mauchly and Eckert. Two years later, in the fall of 1945, the ENIAC was fully functional. The ENIAC consisted of dozens of sections; each nine feet tall, two feet wide, and two feet thick. Together, they weighed thirty tons! It took up an entire room in the basement of the Moore School. The room had to be air-conditioned, otherwise the machine would overheat.

Features of the ENIAC

As far as speed, the ENIAC cut down the computing time of the trajectory tables to thirty seconds. It could add, subtract, multiply, divide, and calculate square roots, among other functions. It was also used for studies on weather predictions, cosmic rays, and atomic energy.


The ENIAC quickly led to other improved computers, and ten years later, it was absolutely obsolete. While it was incredibly fast, even by that day’s standard, it simply cost too much money compared to other, later models. One October 2, 1955, at 11:45 PM, the ENIAC was shut down and officially retired.
Pieces of the original ENIAC are scattered across the country. The University of Pennsylvania still holds four panels, and other places like the Smithsonian and University of Michigan have pieces as well.

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