John Vincent Atanasoff

“I needed a computer, and I needed a computer very, very badly.” (John Atanasoff)

John Vincent Atanasoff, who was later dubbed “the father of the digital computer”, was born on October 4, 1903, near Hamilton, New York. His father, Ivan Atanasov, hailed from Bulgaria and had immigrated to the U.S. in 1889. Upon arrival at Ellis Island the immigration officials americanized his name to John Atanasoff. In Bulgarian the surname is still spelled as Atanasov (Атанасов). Shortly after arriving in the U.S. Ivan married a maths schoolteacher, Iva Lucena Purdy, and in 1903 John Vincent was born – the first of altogether nine children. Ivan accepted a post as electrical engineer in Florida and the family moved to Brewster, Florida where the young John received his schooling. He was a bright child and loved tinkering with electricity – his home in Brewster was the first house they lived in that had electricity.

One day Ivan Atanasoff brought home a Dietzgen slide rule which the young John found fascinating. He found it amazing that, after reading the instructions carefully, he managed to get quick and accurate results with it. The how and why intrigued him so much that he started to study the mathematical principles behind its operations, including the concepts of logarithms. Every time he got stuck, his mother helped him out and explained the problem or gave him a more advanced study book in mathematics. That way he mastered trigonometric functions, differential calculus and logarithms. One of the books his mother gave him dealt with numbering systems using bases other than 10, like the base-2 system (which is now called the binary system). It would later stand him in good stead.

In 1921 Atanasoff went to the University of Florida in Gainesville where he wanted to study theoretical physics – in theoretical physics, mathematics is used to describe certain aspects of physics. Unfortunately the university did not offer that subject and he settled for electrical engineering. In 1925 he graduated with a B.Sc. in electrical engineering. Among the many offers for teaching scholarships he received, including one from Harvard, he accepted the offer from Iowa State College in Ames, Iowa, as this college had an excellent reputation for engineering and science studies. In 1926 he received his M.Sc. in mathematics and he accepted an offer to start teaching mathematics there. In the meantime he was working on his doctorate and in 1930 he received his Ph.D. in theoretical physics from the University of Wisconsin-Madison. Iowa State College offered him a post as assistant professor in mathematics and physics which he accepted. In 1936 it would be followed with a promotion to an associate professorship.

The Atanasoff Berry Computer (the ABC)

During his doctoral study Atanasoff had a serious need for computing facilities but the tools available to him consisted of one IBM tabulator and a mechanical Monroe calculator. When he tried to adapt the IBM tabulator to suit his requirements he was politely informed by IBM that the equipment was on lease and not the property of Iowa State College and “could he please return it to its original state”. The Monroe calculator was not suitable either as it was far too time consuming for the many calculations he needed to perform. A frustrated Atanasoff decided he could build a better and more suitable computing machine himself. He soon realized that a mechanical analog device would not be of much help as it would be too slow and its results would be determined too much by the accuracy and tolerance of the individual machine components. He then remembered one of his mother’s books on numbering systems and realized that the binary system (using base-2) was ideally suited to solve his problems. The concept for the digital computer had been born. In 1939 he could show a prototype of his binary computer. It resulted in receiving a grant of $650 from Iowa State College enabling him to hire a bright electrical engineering graduate student, Clifford E. Berry, to assist him and whom he could pay a small salary. For the next two years the two scientists worked on their computer, which later became known as the Atanasoff-Berry Computer, or the ABC.

It used the binary system, Boolean logic and a regenerative capacitor memory, i.o.w. the memory had to be refreshed (regenerated) every second. It was a special purpose computer and was designed to solve up to 29 linear equations. It could not be programmed to do anything else. The ABC machine weighed about 320 kg, contained 280 vacuum tubes and was about the size of a desk. In comparison, the ENIAC (Electronic Numerator, Integrator, Analyzer and Computer) weighed 30 tons, contained 17,468 vacuum tubes and measured 5.5m x 24m. The ABC could store 60 numbers of 50 bits each, giving it a total capacity of 3000 bits. Input consisted of conventional IBM punch cards and output was done via a front-panel display. It had a speed of one addition per second.

This 2003 Bulgarian envelope commemorates the birth centenary of John Atanasoff.
The picture in the cachet shows the ABC computer in beautiful detail.
It is interesting to note that this picture is virtually identical to the one on Wikipedia
as some of the arrow lines from the Wikipedia illustration are still clearlyl visible.

In December 1940 Atanasoff attended a meeting of the American Association for the Advancement of Science where he met John Mauchly, who, together with J. Presper Eckert, was in the process of developing the ENIAC. The two started talking and Atanasoff invited Mauchly to visit him and have a look at his electrical computing machine. It resulted in a four-day visit by Mauchly to Iowa in 1941, where he had a thorough review of Atanasoff’s design papers and the prototype of the ABC.

World War II

When the U.S. went to war, following the attack on Pearl Harbor on December 7, 1941, both scientists joined the war effort. Before leaving Iowa State College in September 1942, Atanasoff left the submission of the patent application for the ABC and its concepts with a patent lawyer hired by Iowa State College. Unfortunately the papers were never submitted and no patents were filed or registered. At that stage the ABC was still incomplete and not in working order. Atanasoff joined the Naval Ordnance Laboratory in Washington, D.C. and Berry left for Pasadena, California, to work on a Ministry of Defense contract.

While Atanasoff was in Washington, he was visited by Mauchly on a number of occasions for further discussions on the concepts of the ABC, but Mauchly never mentioned at that time that he and Eckert were working on a computer project themselves.

After World War II

Atanasoff stayed in government service after the war and was involved with developing seismographic equipment for long-range detection of explosions. In 1952 he founded the Ordnance Engineering Corporation but sold it a few years later to Aerojet. He stayed with the company and became its Vice President from 1959 – 1961. He retired in 1961.

After the war, Berry started as a physicist at the Consolidated Engineering Company in Pasadena, California, where he made it to director. In 1963 he suddenly committed suicide.

The ABC machine which had been left behind at Iowa State College was never completed. It was dismantled in 1948, but Atanasoff and Berry were never informed of its demise nor were they asked for permission.

Who invented the computer?

In 1947 Mauchly and Eckert filed a patent for a “General Purpose Electronic Computer” which was granted in 1964. It would lead to lengthy legal dispute afterwards. Their Eckert-Mauchly Computer Corporation was taken over by Remington Rand in 1951. In 1955 this company merged with the Sperry Corporation and continued as Sperry Rand Corporation. During the sixties Sperry Rand, now holding the original patent rights from Mauchly and Eckert, started demanding loyalty payments from the different computer manufacturing companies.

In 1967, Honeywell Inc. – a rather small computer manufacturer – filed a lawsuit against Sperry Rand, challenging the validity of their ENIAC patent. They sought the assistance of Atanasoff as they needed him to prove that the ABC was developed much earlier and had been used as the basis for the concepts incorporated in the ENIAC. It proved to be a lengthy and costly trial.

Atanasoff played a crucial role in the process – he produced many letters from his correspondence with Mauchly. One letter from 1941 contained damning evidence: Mauchly wrote “The question in my mind is this: is there any objection, from your point of view, to my building some sort of computer which incorporates some of the features of your machine?”

After many years Honeywell, Inc. v. Sperry Rand Corp. came to its conclusion in April 1973. The court’s ruling invalidated Sperry Rand’s 1964 ENIAC patent for the first general purpose electronic computer. Judge Earle R. Larson stated in one of his findings “Eckert and Mauchly did not themselves invent the automatic electronic computer, but instead derived that subject matter from one Dr. John Vincent Atanasoff.”

The decision clearly established Atanasoff as the father of the digital computer. Presper Eckert was unimpressed. Later he would comment “It's such an outlandish exaggeration to consider that he did it--it's a complete joke. He doesn't tell the truth--that's all. He did some little thing which he never finished and which wouldn't have worked if he had finished it.”
Although it was a landmark decision, it battled to make the evening news. The U.S. was in the grip of the Watergate scandal and the very next day President Nixon fired special prosecutor Archibald Cox – a much more newsworthy story. This lack of publicity resulted in the ENIAC staying in the public mind as the first digital computer, while few people have heard of Atanasoff or the ABC.


Atanasoff has been honored in many ways. In 1990 he received the United States National Medal of Technology. He also received a number of honorary doctorates. Iowa State University (it had changed from a college to a university in 1959) honored its famous son by giving him a Distinguished Achievement Citation. In addition they made the film “From one John Vincent Atanasoff” which was completed in 1981. He was also inducted in the Iowa Inventors Hall of Fame.

Bulgaria awarded him in 1970 already its highest scientific order – the Order of Saints Cyril and Methodius, First Class. In addition many schools, high schools and streets in Bulgaria carry his name.

On the philatelic front Bulgaria has issued one stamp, one souvenir sheet and a pre-stamped envelope to commemorate Atanasoff. None have been issued by the U.S. Postal Service.

After a lengthy illness John Vincent Atanasoff died of a stroke on June 15, 1995, in Maryland.

In 1997 the Iowa State University commenced a project, with a US$350,000 budget, to rebuild a fully functional replica of the Atanasoff-Berry Computer. Today this replica is on display on the first floor of the Center for Computation at Iowa State University.

© Wobbe Vegter, 2008

[ Back ]