ENIAC Begins Working at the University of Pennsylvania

ENIAC Begins Working at the University of Pennsylvania

On February 14, 1946, the electronic numerical integrator and computer, known as ENIAC, was unveiled to the public at a press conference held at the Moore School of Electrical Engineering of the University of Pennsylvania. ENIAC was a major achievement in the development of modern computers, and it owed much to the pioneering contributions of female computer scientists.

ENIAC was built by John W. Mauchly and John Presper Eckert Jr. for the U.S. army, which asked them to construct a device to calculate the ballistic trajectories of artillery shells more efficiently. It was the first completely electronic digital computer. ENIAC predated the invention of the microchip and other miniaturized computer devices, so with its 18,000 vacuum tubes and 40 major separate components, ENIAC weighed over 30 tons and took up nearly 2,000 square feet of space. It could perform roughly 5,000 calculations per second—incredibly fast by the standards of that day—and solved in seconds mathematical problems that had previously taken days to do by hand. Punchcard machines built by IBM (International Business Machines) were later incorporated into ENIAC's design in order to make the inputting and storage of data more efficient.

During World War II, the army maintained some 80 female mathematicians and computer programmers at the University of Pennsylvania. They worked on artillery shell calculations, almost all of which were performed laboriously by hand. In 1945, as ENIAC was being constructed, six women were chosen from their ranks to be the machine's programmers: Kathleen McNulty Mauchly Antonelli, Jean Jennings Bartik, Frances Snyder Holberton, Marlyn Wescoff Meltzer, Frances Bilas Spence, and Ruth Lichterman Teitelbaum. Together they devised the means to program the immense machine, which often involved manually working thousands of switches and re-routing a variety of cables and other equipment. Thanks to their efforts, ENIAC's first public computations on February 14, 1946, were a success.

Since World War II had already ended, ENIAC was put to other uses in addition to solving ballistics equations. In 1947 it was moved to the army's Aberdeen Proving Grounds in Aberdeen, Maryland, and for nearly a decade, until it was put out of service in October 1955, ENIAC was used in a variety of research programs involving such matters as wind tunnels, nuclear weapons, and advanced weather forecasting. Although it was designed to operate continuously, 24 hours a day, the machine was usually shut down one-third of the time, so that the vacuum tubes could be replaced and other parts serviced. ENIAC's successors, such as EDVAC (the electronic discrete variable automatic computer), resolved or minimized many of these problems and eventually made ENIAC obsolete.