Penn Library

John W. Mauchly and the Development of the ENIAC Computer

The John Atanasoff Controversy

Two controversies serve as counterpoints to the story of John Mauchly and Pres Eckert and the invention of the ENIAC computer. The first of these concerned the contributions of an Iowa State College professor, John V. Atanasoff, who had designed and built an electronic computing device between 1937 and 1942 with the assistance of his graduate student, Clifford Berry. While there are some doubts as to whether the Atanasoff-Berry Computer (ABC) was ever fully operational, Mauchly visited Atanasoff during the summer of 1941 and had a close look at the machine. The controversy has been over the extent to which Mauchly borrowed Atanasoff's ideas, and whether Atanasoff was the true inventor of the modern electronic computer.
Letter from John V. Atanasoff to J. W. Mauchly, 7 March 1941. (click to expand to 165k)

News account of ABC, 7 April 1942 (click to expand to 86k)
Recognition for invention is highly prized among scientists and academic engineers, whose rewards tend to be more intangible than those of their counterparts in industry. Presper Eckert has been more fortunate than Mauchly in this regard, because his reputation is based on his contributions to the engineering work involved in developing the ENIAC computer. The material artifact itself stood as a demonstration of the superb engineering that had produced an operational large-scale electronic computer. As the principal architect during the early design work on the ENIAC, Mauchly could only rest his claims on the design contributions that he had made to the project. The invisibility of design work has made it possible for others to question from where Mauchly had derived his ideas.
There is actually little doubt that Mauchly was inspired by Atanasoff's work. In 1941 Atanasoff knew more about basic elements of electronic computation than Mauchly and openly shared this knowledge. The ABC, with its several hundred vacuum tubes, represented one of the most complicated electronic circuits at the time, and Mauchly, with his then very limited experience, would have been impressed by its design. Still, the ABC had been designed as a special purpose computer designed only to solve large systems of linear equations. Certain aspects of its design also precluded the ABC from computing at truly electronic speeds. Upon arriving at the Moore School, Mauchly gained access to many other sources of ideas not the least of which was the concept of ganged adding machines proposed by the faculty member Irven Travis. The ENIAC was, in other words, a combination of many different design ideas. Mauchly may have continued to draw ideas from Atanasoff's further reflections on electronic computing, but it was ultimately Mauchly who, working with Eckert, designed the first general- purpose electronic computer. Whether Mauchly gave credit to Atanasoff's contributions remains a separate historical question.
Four panels of ENIAC, with Betty Jennings and Frances Bilas (right) arranging the program settings on the master programmer, 1946. (click to expand to 83k)

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