For years, computer historians asserted that the first electronic computers were invented in the mid 1940s. Most cite the Colossus, built by mathematicians Alan M. Turing and M.H.A. Newman at Bletchley Research Establishment in England. Or in the U.S., ENIAC, the Electronic Numerical Integrator and Computer, built by John W. Mauchly and J. Presper Eckert. But history has come to show that it was in 1937 that an alumnus of the University of Florida Electrical Engineering Department, John Vincent Atanasoff (BSEE ’25), went for a lonely drive and, in a bar, scribbled what became the beginning pillars of modern computing on a cocktail napkin. In doing so, he invented the digital computer.
The Story
John Vincent Atanasoff was born in 1903 near Hamilton, New York. His father, a Bulgarian immigrant, was an electrical engineer and his mother was a math teacher. Growing up in Brewster, Florida, he completed high school in just two years, then enrolling at the University of Florida. He received his Bachelor of Science degree in electrical engineering in 1925. Continuing his education at Iowa State College (later Iowa State University), he earned a master’s degree in mathematics in 1926. Atanasoff relocated to the University of Wisconsin-Madison to earn his Ph.D. in theoretical physics. After completing his doctorate, he then returned to Iowa State, having accepted a position as an assistant professor in mathematics and physics.
At the time, any attempts at creating computers were really just attempts to create better calculators. Atanasoff had long been frustrated with the operation of state-of-the-art calculators and began designing his own.
At this point in the story, we turn to Iowa State University’s account of Atanasoff’s career.
In 1936 he engaged in his last effort to construct a small analog calculator. With Glen Murphy, then an atomic physicist at Iowa State College, he built the “Laplaciometer,” a small analog calculator. It was used for analyzing the geometry of surfaces. Atanasoff regarded this machine as having the same flaws as other analog devices, where accuracy was dependent upon the performance of other parts of the machine.
The obsession with finding a solution to the computing problem built to a frenzy in the winter months of 1937. One night, frustrated after many discouraging events, he got into his car and started driving without a destination in mind. Two hundred miles later, he pulled onto a roadhouse in the state of Illinois. Here, he had a drink of bourbon and continued thinking about the creation of the machine. No longer nervous and tense, he realized that this thoughts were coming together clearly. He began generating ideas on how to build this computer, writing them down on a cocktail napkin. His four main ideas that came together that night, and were later critical for establishing he as inventor, and the ABC as the first electronic digital computer, including:
- He would use electricity and electronics for the media of the computer, which would give it speed
- He would use base-2, or the binary number system, which would simplify its computational process.
- He would use regenerative memory, which would reduce the cost of building the machine.
- He would compute with direct logical action rather than enumeration, which would give it increased accuracy.
After receiving a grant of $650 from Iowa State College in March 1939, Atanasoff was ready to undertake the construction of the computer. To help him accomplish his goal, he hired a particularly bright electrical engineering student, Clifford E. Berry. From 1939 until 1941 they worked at developing and improving the device, later named the Atanasoff Berry Computer (ABC). In 1942 Atanasoff left Ames, Iowa and Iowa State on leave for a defense-related position at the Naval Ordnance Laboratory in Washington, D.C. Near the same time, Clifford Berry accepted a defense-related job in California. Although Iowa State College had hired Chicago patent lawyer Richard R. Trexler, the patenting of the ABC was never completed.1
The outbreak of World War II meant new jobs and new priorities for Atanasoff and Berry—both researchers took defense-related jobs to help with the war effort. When he returned to Iowa State in 1948, Atanasoff found that the early builds of the ABC had been dismantled, with only a few parts remaining. Neither researcher had been informed. Eventually returning to the Washington, D.C. area, Atanasoff went to work for the Navy, serving as director of the Navy Fuse Program at the Naval Ordnance Laboratory. But colleagues began suggesting to Atanasoff that the recently-completed ENIAC, designed by John Mauchly and J. Presper Eckert, had at its core many of the same ideas innovated by Atanasoff and Berry.
Interestingly, in 1941, Atanasoff had written to Mauchly, sharing the promise of his nascent technology with his colleagues. The letter was followed by a visit from Mauchly.
Atanasoff, who by May of 1941 ‘knew we could build a machine that could do almost anything in the way of computing,’ decided the ABC could be converted into a digital, electronic differential analyzer after a colleague from M.I.T. told him that workers there were considering incorporating electronics into a new analog version of the analyzer. Atanasoff wrote of the possibility to Mauchly, and the two men discussed it extensively when Mauchly visited Atanasoff for the better part of a week in June, 1941. During that visit Atanasoff also demonstrated the ABC, which was then almost ready to run. Four years later the ENIAC realized Atanasoff’s vision. 2
The debate as to the provenance of the digital computer eventually played out in a courtroom. During a 1967 patent case between Honeywell Inc. and the Sperry Rand Corporation, the assertion was made that, in fact, the ENIAC was derived from Atanasoff’s intellectual property.
Much impressed by Atanasoff’s testimony in the case, Judge Earl R. Larson of the U.S. District Court in Minneapolis concluded on October 19, 1973, that the ENIAC patent was invalid. Mauchly and Eckert, he found, ‘did not themselves first invent the automatic electronic digital computer, but instead derived that subject matter from one Dr. John Vincent Atanasoff.’ 2
Legacy
Many of Atanasoff’s innovations—conceived on that fateful night in the winter of 1937— live on in today’s computers. The choice to store binary digits in capacitors, the idea of the logic circuit, and the the basic architecture of modern computing devices (separate I/O, CPU, and memory) are still bedrocks of computer architecture.
From Scientific American: “In contrast to mechanical or electromechanical computers, electronic computers operate primarily by means of such electron devices as vacuum tubes, transistors or, now, microchips; electrons, rather than computer parts, do most of the moving. Finding a way to preserve memory in capacitors was certainly important, but Atanasoff’s greatest achievement was probably the development of a complex electronic switch known as a logic circuit. While he was at the Illinois roadhouse, he had envisioned two memory units, which he called abaci. Then he visualized, as he put it, a ‘black box’—the logic circuit—into which would pass the numbers held in memory; on the basis of hard-wired logical rules, the black box would then yield the correct results of an addition or subtraction of the numbers at output terminals.”
Would the digital computer have been invented without Atanasoff? He himself suggested that without the ABC, the digital computer would have been delayed by ten years or so.3 But the fact remains that in 1937, an alumnus of the University of Florida Electrical Engineering Department conceived of the digital computer and made it a reality. The rest is computing history.
1 “John Vincent ATANASOFF and the Birth of Electronic Digital Computing.” Iowa State University Department of Computer Science, https://jva.cs.iastate.edu/jvabio.php , retrieved 7/25/25.
2 “Dr. Atanasoff’s Computer.” Scientific American, August 1988, by Allan Mackintosh. http://encarta.msn.com/sidebar_761599223/Dr_Atanasoff%5C’s_Computer.html, retrieved 7/25/25.
3 “Computer Pioneers: Clifford Edward Berry.” IEEE Computer Society. By J.A.N. Lee. https://history.computer.org/pioneers/berry.html, retrieved 8/1/25.