Martin Campbell-Kelly’s September article on the origins of computing traces the history of machine computation from Charles Babbage, the 18th century British mathematician, through the 20th century. Yet according to many of our readers, we made a critical omission.

John Hauptman, a professor of physics at Iowa State University, writes:

The first person to build and operate an electronic digital computer was a physics professor, as correctly noted in your excellent article “Dr. Atanasoff’s Computer,” Scientific American, August 1988 [not online]. Atanasoff’s first computer was a 12-bit 2-word machine running at 60Hz wall-plug frequency and could add and subtract binary numbers stored in a regenerative memory using a logic unit built with seven triode tubes. This was 1937. There was no war, no Pearl Harbor, just a theoretical physicist trying to solve problems in quantum mechanics with his students at Iowa State College in Ames, Iowa.

Edward B. Watters of Newberg, Oregon, points to a legal decision that also calls into question the traditional story—namely, that the first digital computer was the ENIAC, a machine built in 1945 by J. Presper Eckert and John W. Mauchly of the Moore School of Electrical Engineering at the University of Pennsylvania:

In one of the longest cases, almost five years, in the history of the U.S. Federal Courts, Honeywell v. Sperry Rand , U.S. District Judge Earl R. Larson concluded in the verdict, published on October 19, 1973, that the Eckert and Mauchly patent for the ENIAC was invalid. Judge Larson declared that Eckert and Mauchly “did not themselves first invent the [ENIAC] automatic electronic digital computer, but instead derived that subject matter from one Dr. John Vincent Atanasoff.”

We asked Campbell-Kelly, a professor of computer science at the University of Warwick in England and the author (along with William Aspray) of Computer: A History of the Information Machine, for his views on the Atanasoff controversy. He replies:

Computer historians are cautious about asserting priorities to inventors. I did not state that Eckert and Mauchly invented the electronic computer, but rather that they invented a particular computer, the ENIAC. I also said that “computing entered the electronic age with the ENIAC” which is true in the sense of a practical computing instrument of fairly broad application.

There were several electronic computing developments during World War II, both preceding and contemporaneous with the ENIAC, of which the Atanasoff machine was one—others included the NCR code-breaking machines, the Zuse Z4 computer in Germany, and the Colossus code breaking computer in the U.K. In a short article I could not acknowledge them all.

Atanasoff’s machine was a little-known computer that was restricted to a narrow class of problem, was not programmable, and was never fully functional. Atanasoff discontinued development in 1942. The Atanasoff computer was virtually unknown until 1971 when it was uncovered in a patent suit brought by Honeywell against Sperry Rand to invalidate the ENIAC patent. During the trial it was revealed that Mauchly had visited Atanasoff and saw his computer in June 1941. What he learned from this visit cannot be known, but the design of the ENIAC bore no resemblance to the Atanasoff computer. Mauchly himself claimed that he took away “no ideas whatsoever.” Although the judge gave priority of invention to Atanasoff, this was a legal judgment that surprised many historians.

In the article, Campbell-Kelly goes on to emphasize that the most important innovation—and one generally overlooked by casual observers—was the development of the stored-program computer concept by John von Neumann and collaborators in 1945. He writes that “this layout, or architecture, makes it possible to change the computer’s program without altering the physical structure of the machine. Moreover, a program could manipulate its own instructions. This feature … would confer a powerful flexibility that forms the very heart of computer science.”

What do you think? Should Eckert and Mauchly continue to receive credit for inventing the first electronic computer? Or Atanasoff? Or have von Neumann’s contributions to computing theory been overlooked in favor of less important but more tangible physical machines?