Since ancient times people have used calculating devices, but it wasn’t until 1946 that the first general-purpose digital computer was developed. With the onset of World War II, the ballistic research laboratory at Aberdeen Proving Ground was in need of a more advanced way to prepare firing and bombing tables for the Army and Army Air Corps. Until that time, these calculations had been carried out on a continuous variable calculator, which was not only extremely slow, but also subject to frequent breakdowns. In an effort to improve the efficiency of their equipment, the staff at Aberdeen began working closely with the University of Pennsylvania’s Moore School of Electrical Engineering. Through this coordinated effort a plan was also formulated to produce the world’s first “true” computer. Using this plan, two engineers from the Moore School went on to develop ENIAC (Electronic Numerical Integrator And Computer). Completed in 1946, it weighed more than 30 tons, and occupied more than 1500 square feet. Used to calculate firing tables, as well as conduct top-secret research in the development of the hydrogen bomb, ENIAC ushered the world into the computer age and paved the way for smaller, more powerful computers.