John Atanasoff and the first Electronic Digital Computer

John Vincent Atanasoff

On October 4, 1903, American physicist and inventor John Vincent Atanasoff was born. He is best known for being considered as one of the inventors of the electronic digital computer. Even computer scientists most probably haven’t heard anything of this computer pioneer. Of course you will have heard about Alan Turing or John von Neumann, who are traditionally referenced as being the fathers of the computer. Maybe, when you are European or even German, then you most probably will have heard of Konrad Zuse, who in near total intellectual isolation constructed the first universal computer Z3, which became operational in May 1941. So why is it, we haven’t heard of John Atanasoff

John Atanasoff, of Bulgarian, French and Irish ancestry, was born on October 4, 1903 in Hamilton, New York to Ivan Atanasoff, an electrical engineer and a school teacher, who had immigrated to the United States in 1889. Atanasoff’s mother, Iva Lucena Purdy, was a teacher of mathematics. Atanasoff was raised in Brewster, Florida. Already at the age of nine he learned to use a slide rule and logarithms. In 1925, he received his bachelor of science degree in electrical engineering from the University of Florida and continued at Iowa State College, where he earned his master’s degree in mathematics in 1926. In 1930 by he received a PhD in theoretical physics from the University of Wisconsin–Madison and accepted a professorship at Iowa State College in mathematics and physics.

While working at his PhD thesis, Atanasoff became rather frustrated about the available mechanical calculation machines and began to search for faster methods of computation. In 1936 Atanasoff invented an analog calculator for analyzing surface geometry. The fine mechanical tolerance required for good accuracy pushed him to consider digital solutions. According to Atanasoff, several operative principles of his famous invention, the Atanasoff–Berry Computer (ABC), were conceived in a flash of insight during the winter of 1937–1938 after a drive to Rock Island, Illinois. One night in a bar on the Illinois-Iowa border, after another frustrating day performing tedious mathematical calculations in his lab, Atanasoff hit on the idea that the binary number system and electronic switches, combined with an array of capacitors on a moving drum to serve as memory, could yield a computing machine that would make his life as a scientist easier. With a grant of $650 received in September 1939 Atanasoff went back to his office and with the assistance of his graduate student Clifford Berry, he built the machine by November of that year. The prototype really worked. The whole world changed. 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 used separate regenerative capacitor memory that operated by a process still used today in DRAM memory.

Between 1954 and 1973, Atanasoff was a witness in the legal actions brought by various parties to invalidate electronic computing patents issued to John Mauchly and J. Presper Eckert, who designed ENIAC, the first general purpose electronic digital computer. The patents were owned by computer manufacturer Sperry Rand. But in 1973 a court declared that the patent on the Sperry Rand UNIVAC device was invalid and declared Atanasoff the inventor of the electronic digital computer, opening the intellectual property gates to the computer revolution.

In 1980, Dr. John Atanasoff gave a lecture at the Digital Computer Museum in Massachusetts, where he discusses his life, the events that lead to his breakthroughs in computing and the design of the Atanasoff–Berry Computer.

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