Atanasoff-Mauchly controversy

The Atanasoff-Mauchly controversy was the lengthy and heated debate about who deserves the credit for the invention of electronic computing devices: John Vincent Atanasoff, the creator of the Atanasoff-Berry Computer (hereinafter the ABC), or John Mauchly, the creator of the ENIAC.

John Mauchly's role in the ENIAC produced two related controversies, which diligent research has only partially cleared up.

In the first, after he became the professor of physics at Ursinus College in 1933, Mauchly became interested in mathematical modelling of meteorological events, and soon discovered just how much calculation was involved in such modeling. He then began to consider machines to perform such computations, and began to experiment with simple electronic devices, thinking that that technological approach might allow high-speed computation.

He then met Atanasoff at the annual meeting of the American Association for the Advancement of Science (AAAS) in Philadelphia, in December 1940, and learned of the latter's work on the ABC - which seemed from a brief description to be just the kind of high-speed computing device that Mauchly needed. He then went to see it in person in Ames, in June, 1941, and spent several days studying the ABC in detail, and discussing it, and its possible future evolution, with Atanasoff, and the latter's co-worker Clifford Berry.

This was about a year before he started on the ENIAC, in about August, 1942 - and it raises the question 'did what he learned about the ABC, and its design, have a significant influence on the eventual design of, and work on, the ENIAC'? It is not easy, at this temporal distance, to answer that - but there are certain indisputable factual observations we can make:

• The ABC, although more limited in capability than the kind of machine that Mauchly had apparently been thinking of, did demonstrate that high-speed electronic computing devices were feasible. (The purely electronic portion of the ABC eventually worked fine; its main remaining problem was elsewhere.)
• It also demonstrated that digital devices were a viable (and likely preferred) approach to powerful computing devices. (Recent prior advanced work in this area, such as the differential analyzer, has used an analogue approach.) Both of these points were all well-explained to Mauchly on his visit.
• The architecture of the ENIAC was very different from the ABC; not just in its capabilities (and thus its high-level design), but also in its lower-level details (e.g. the ABC was a parallel binary machine; ENIAC was a serial decimal machine).

So, it is clear that the ENIAC involved a great deal of pioneering thinking, and in a very different direction from the ABC. But how much did Mauchly learn from studying the ABC, and from his discussions with Atanasoff (including during communication via post, after his visit); how much of what he learned was used in the ENIAC; and, perhaps most important, how much of an inspiration to Mauchly's own thinking was Atanasoff's work?

We may never know, for sure; indeed, it is likely that Mauchly himself did not clearly and completely understand the influence that Atanasoff's work had on his own thinking. To put it another way, would Mauchly's own path from 1940 forward have looked roughly the same had he never met Atanasoff? As with all 'alternative histories', we can only speculate; all we can really do is study the ABC, and the ENIAC, and wonder.

The second of the two related controversies was that unfortunately, when the time came, much later, to patent the ENIAC's contributions, the patent attempted to also claim many of the ABC's broader innovations - including its use of digital electronics to do computing. (In fairness, it should be mentioned that there are claims that it was the lawyers who drew up the patent who so broadened the claims, not Mauchly and Eckert.) This fact still later led to the overturning of the over-broad ENIAC patent, in a celebrated trial in 1973 - in the preparation for which, the then-forgotten ABC was brought to light, and to general attention. Had the patent only claimed Mauchly and Eckert's many valuable, real, contributions, it would have been fine.

Unfortunately, the whole controversy led to a great deal of division and ill-will; much of the computer world was divided into two vehemently-opposed camps, the 'Atanasoff' camp, and the 'Mauchly/Eckert' camp, which often quite bitterly disputed to whom should go the credit for 'inventing the computer'. This was most unfortunate, as the machines of Atanasoff and Mauchly and Eckert both were major steps along the path from Babbage to modern computers; the struggle over credit has led to both sides not getting the recognition they both really do deserve.

Further reading

• Herman H. Goldstine, The Computer from Pascal to von Neumann, Princeton University, Princeton, 1972 - describes briefly his pre-ENIAC conversations with Mauchly
• Nancy Stern, From ENIAC To UNIVAC: An Appraisal of the Eckert-Mauchly Computers, Digital Press, Bedford, 1981
• Kathleen Mauchly, "John Mauchly's Early Years", Annals of the History of Computing, Vol. 6, No. 2, 1984, pp. 116-138 - contains detail on his work before his visit to Atanasoff
• R. K. Richard, Electronic Digital Systems, John Wiley, New York, 1966 - the work which initially brought the ABC to the world's attention
• Alice Rowe Burks, Arthur W. Burks, The First Electronic Computer: The Atanasoff Story, University of Michigan, Ann Arbor, 1988 - Appendix B contains a lengthy and careful analysis of Kathleen Mauchly's article (above)
• Alice Rowe Burks, Who Invented the Computer? The Legal Battle That Changed History, Prometheus, Amherst, 2003 - a somewhat tendentious work, which attempts to claim the crown for Atanasoff
• Allan R. Mackintosh, "The First Electronic Computer", Physics Today, Volume 40, Issue 3, March 1987 - a fairly well-known early cannon-ball in the dispute

External links

• Alice R. Burks, Arthur W. Burks, Who Invented the Computer? A Memoir of the 1940s, Michigan Quarterly Review, Volume XXXVI, Issue 2, Spring 1997
• Allan R. Mackintosh, Dr. Atanasoff's Computer, Scientific American, Volume 259, Number 2, August 1988, pp. 90-96 - likely a variant on the prior 'Physics Today' article
• Saul Rosen, Origins of Modern Computing - equally tendentious, from the other direction
• Lee Loevinger, The Invention and Future of the Computer, John Marshall Journal of Information Technology & Privacy Law, Volume 15, Issue 1, Fall 1996 - a somewhat less-loaded summary, by a non-technologist outsider
• John Mauchly visits Ames
• Patent/Court Case