John Mauchly Biography

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World of Invention on John Mauchly

John Mauchly, with J. Presper Eckert, designed and built several significant computers in the 1940s--ENIAC, EDVAC, BINAC, and UNIVAC. Mauchly was born in Cincinnati, Ohio, and became interested in science while very young. He studied engineering and physics at Johns Hopkins University, receiving his Ph.D. in 1932; he spent the next year there as a research assistant. In 1934, when he became a faculty member at Ursinus College, he carried out weather research.

All of this work required large amounts of computation, and he began to consider how to make calculating easier. After taking a course at the University of Pennsylvania's Moore School of Electrical Engineering in the summer of 1941, he was asked to join the faculty. There he met Eckert, who was a student.

Because of World War II, the university had a contract to develop a calculating machine for the United States Army. Mauchly and Eckert designed and patented ENIAC (Electronic Numerical Integrator And Computer), which was much faster than earlier computers and used vacuum tubes for electronic data processing. However, it required the slower punched cards for the program and intermediate processing results. Also, each processing sequence had to be set up by hand.

The school next began work on EDVAC (Electronic Discrete Variable Automatic Computer), a computer milestone featuring a stored program, in which the program and data are both in the computer's memory and treated alike. Mauchly and Eckert designed the memory, using mercury-filled delay lines to retain the incoming electronic signal as a much slower sound wave.

In 1948, the University wanted control of all patents for equipment produced by its faculty. Mauchly and Eckert resigned and formed their own firm, the Electronic Control Company, to produce stored-program computers based on the ENIAC patents. Their first computer, in 1949, was BINAC (BINary Automatic Computer), a fast and relatively small computer to be used on a guided missile. It was the first computer to use magnetic tape for input and output, and also featured two processing units that performed the same calculations to guarantee accuracy. At the same time, the two men were building a much larger computer called UNIVAC (UNIVersal Automatic Computer), completed in 1950. It was the first widely-available commercial computer to use stored programs.

Because they were losing money in 1950, Mauchly and Eckert sold their company and patents to the calculator and typewriter manufacturer Remington Rand. After the sale, Mauchly formed a computer-development consulting firm. He also invented the critical path method (CPM) of scheduling complex projects on the computer, which is widely used in business and research.

During the 1960s, Mauchly and Eckert were sued by Honeywell, a computer manufacturer, and John Atanasoff, a physics professor at Iowa State University. They claimed that the patents were based on Atanasoff's A-B-C computer, which he had demonstrated for Mauchly in 1941, before ENIAC was built. Mauchly and Eckert maintained that their design work was largely done before Mauchly met Atanasoff, and that the two machines were different. However, in 1973, the judge ruled in Atanasoff's favor, declaring the patents invalid.

Mauchly received numerous honors for his work, including awards from the American Federation of Information Processing Societies and the Institute of Electrical and Electronics Engineers. In addition, in 1947 he helped found the Association for Computing Machinery, the world's largest computing society.