John Vincent Atanasoff

Atanasoff's father, Ivan Atanasov, was of Bulgarian origin, born in 1876 in the village of Boyadzhik, close to Yambol, then in the Ottoman Empire.

While Ivan Atanasov was still an infant, his own father was killed by Ottoman soldiers after the Bulgarian April Uprising.

In 1889, Ivan immigrated to the United States with his uncle.

John's father later became an electrical engineer, whereas his mother, Iva Lucena Purdy (of mixed French and Irish ancestry), was a teacher of mathematics.

Atanasoff was raised in Brewster, Florida.

Young Atanasoff's ambitions and intellectual pursuits were in part influenced by his parents, whose interests in the natural and applied sciences cultivated in him a sense of critical curiosity and confidence.

At the age of nine, he learned to use a slide rule, followed shortly by the study of logarithms, and subsequently completed high school at Mulberry High School in two years.

John Vincent Atanasoff,, (October 4, 1903 – June 15, 1995) was an American physicist and inventor credited with inventing the first electronic digital computer.

Atanasoff was born on October 4, 1903, in Hamilton, New York to an electrical engineer and a school teacher.

In 1925, Atanasoff received his Bachelor of Science degree in electrical engineering from the University of Florida.

He continued his education at Iowa State College and in 1926 earned a master's degree in mathematics.

Atanasoff invented the first electronic digital computer in the 1930s at Iowa State College (now known as Iowa State University).

He completed his formal education in 1930 by earning a PhD in theoretical physics from the University of Wisconsin–Madison with his thesis, The Dielectric Constant of Helium.

Upon completion of his doctorate, Atanasoff accepted an assistant professorship at Iowa State College in mathematics and physics.

Partly due to the drudgery of using the mechanical Monroe calculator, which was the best tool available to him while he was writing his doctoral thesis, Atanasoff began to search for faster methods of computation.

At Iowa State, Atanasoff researched the use of slaved Monroe calculators and IBM tabulators for scientific problems, with which controlled the Monroe using the output of an IBM.

In 1936 he invented an analog calculator for analyzing surface geometry.

At this point, he was pushing the boundaries of what gears could do and the fine mechanical tolerance required for good accuracy pushed him to consider digital solutions.

According to Atanasoff, several operative principles of the ABC were conceived by him during the winter of 1938 after a drive to Rock Island, Illinois.

The key ideas employed in the ABC included binary math and Boolean logic to solve up to 29 simultaneous linear equations.

The ABC had no central processing unit (CPU), but was designed as an electronic device using vacuum tubes for digital computation.

It also had regenerative capacitor memory that operated by a process similar to that used today in DRAM memory.

With a grant of $650 received in September 1939 and the assistance of his graduate student Clifford Berry, the Atanasoff–Berry Computer (ABC) was prototyped by November of that year.

Atanasoff first met John Mauchly at the December 1940 meeting of the American Association for the Advancement of Science in Philadelphia, where Mauchly was demonstrating his "harmonic analyzer", an analog calculator for analysis of weather data.

Atanasoff told Mauchly about his new digital device and invited him to see it.

In June 1941 Mauchly visited Atanasoff in Ames, Iowa for four days, staying as his houseguest.

Atanasoff and Mauchly discussed the prototype ABC, examined it, and reviewed Atanasoff's design manuscript.

In 1941 Atanasoff left Iowa State for a wartime assignment as Chief of the Acoustic Division with the Naval Ordnance Laboratory (NOL) in Washington, D.C. No patent application for the ABC was subsequently filed by Iowa State College.

Mauchly visited Atanasoff multiple times in Washington during 1943 and discussed computing theories, but did not mention that he was working on a computer project himself until early 1944.

By 1945 the U.S. Navy had decided to build a large-scale computer, on the advice of John von Neumann.

Atanasoff was put in charge of the project, and he asked Mauchly to help with job descriptions for the necessary staff.

However, Atanasoff was also given the responsibility of designing acoustic systems for monitoring atomic bomb tests.

That job was made the priority, and he participated in the testing at Bikini Atoll in July 1946.

By the time he returned from the testing the NOL computer project was shut down due to lack of progress, again on the advice of von Neumann.

In June 1954 IBM patent attorney A. J. Etienne sought Atanasoff's help in breaking an Eckert–Mauchly patent on a revolving magnetic memory drum, having been alerted by Clifford Berry that the ABC's revolving capacitor memory drum may have constituted prior art.

Atanasoff agreed to assist the attorney, but IBM ultimately entered a patent-sharing agreement with Sperry Rand, the owners of the Eckert–Mauchly memory patent, and the case was dropped.

Atanasoff was deposed and testified at trial in the later action Honeywell v. Sperry Rand.

In that case's decision, Judge Earl R. Larson found that "Eckert and Mauchly did not themselves first invent the automatic electronic digital computer, but instead derived that subject matter from one Dr. John Vincent Atanasoff".

Challenges to his claim were resolved in 1973 when the Honeywell v. Sperry Rand lawsuit ruled that Atanasoff was the inventor of the computer.

His special-purpose machine has come to be called the Atanasoff–Berry Computer.