The Atanasoff – Berry Computer ( ABC ) was the first electronic digital computing device.

Atanasoff and Clifford Berry's computer work was not widely known until it was rediscovered in the 1960s, amidst conflicting claims about the first instance of an electronic computer.

At that time, the ENIAC was considered to be the first computer in the modern sense, but in 1973 a U. S. District Court invalidated the ENIAC patent and concluded that the ENIAC inventors had derived the subject matter of the electronic digital computer from Atanasoff ( see Patent dispute ).

Judge Larson explicitly stated, " 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 ".

In 1939, John Vincent Atanasoff and Clifford E. Berry of Iowa State University developed the Atanasoff – Berry Computer ( ABC ), The Atanasoff-Berry Computer was the world's first electronic digital computer.

* The Atanasoff-Berry computer is considered the first electronic digital computing device built by John Vincent Atanasoff and Clifford Berry at Iowa State University during 1937 – 1942.

* The American Atanasoff – Berry Computer ( ABC ) ( shown working in summer 1941 ) was the first electronic computing device.

For a variety of reasons ( including Mauchly's June 1941 examination of the Atanasoff – Berry Computer, prototyped in 1939 by John Atanasoff and Clifford Berry ), US patent 3, 120, 606 for ENIAC, granted in 1964, was voided by the 1973 decision of the landmark federal court case Honeywell v. Sperry Rand, putting the invention of the electronic digital computer in the public domain and providing legal recognition to Atanasoff as the inventor of the first electronic digital computer.

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 ".

In 1903, John Vincent Atanasoff, creator of the first digital electronic computer, was born in Hamilton.

* John V. Atanasoff with Clifford Berry successfully test the Atanasoff – Berry Computer, the first electronic digital computing device.

In 1988 he wrote a biography of John Vincent Atanasoff, the Iowa State College professor who invented the first electronic digital computer in 1939.

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, which were owned by computer manufacturer Sperry Rand.

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.

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.

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

Atanasoff – Berry Computer replica at 1st floor of Durham Center, Iowa State University

The ABC was built by Dr. Atanasoff and graduate student Clifford Berry in the basement of the physics building at Iowa State College during 1939 – 42.

In 1997, a team of researchers led by John Gustafson from Ames Laboratory ( located on the Iowa State campus ) finished building a working replica of the Atanasoff – Berry Computer at a cost of $ 350, 000.

Atanasoff – Berry Computer replica at 1st floor of Durham Center, Iowa State University

Atanasoff – Berry Computer replica at 1st floor of Durham Center, Iowa State University

Letters he wrote to Atanasoff show that he was at one time at least considering building on Atanasoff's approach.

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

( During the Philadelphia trip, Atanasoff and Berry also conducted a patent search at the Patent Office in Washington, D. C .)

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

Atanasoff died in 1995 of a stroke at his home after a lengthy illness.

* The Atanasoff Archives at Iowa State

* Atanasoff Personal Papers at Iowa State

* John V. Atanasoff Dies at Age 91 Invented First Electronic Computer – Washington Post Obituary, 1995

The CYCLONE, was an early computer built in 1959 by John Vincent Atanasoff and his assistant Clifford Berry at Iowa State College ( now Iowa State University ), was based on the Institute for Advanced Study ( IAS ) architecture developed by John von Neumann.

* Mollenhoff Papers at Iowa State U. on John Atanasoff

* 1903 – John Vincent Atanasoff, American computer pioneer ( d. 1995 )

* October 4 – John Vincent Atanasoff, American computer engineer ( d. 1995 )

Prof. John Vincent Atanasoff (; October 4, 1903 – June 15, 1995 ) was an American physicist and inventor.

Atanasoff ’ s Computer ,” Scientific American, August 1988 ( Archived 2009-10-31 )

American scientists and inventors of Bulgarian descent include John Atanasoff, Peter Petroff, and Assen Jordanoff.

However, its intermediate result storage mechanism, a paper card writer / reader, was unreliable, and when inventor John Vincent Atanasoff left Iowa State College for World War II assignments, work on the machine was discontinued.

This problem was not solved by the time Atanasoff left the university for war-related work.

Machines such as the Z3, the Atanasoff – Berry Computer, the Colossus computers, and the ENIAC were built by hand using circuits containing relays or valves ( vacuum tubes ), and often used punched cards or punched paper tape for input and as the main ( non-volatile ) storage medium.

However, upon seeing how bad the footage of the video was, Perry threw up, Larriva threatened to quit, and Atanasoff was not seen around for days.

The ABC was dismantled by Iowa State University, after John Atanasoff was called to Washington, D. C. to do physics research for the U. S. Navy.

Capacitors had been used for earlier memory schemes such as the drum of the Atanasoff – Berry Computer, the Williams tube and the Selectron tube.

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.

In September 1942 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.

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

Following World War II Atanasoff remained with the government and developed specialized seismographs and microbarographs for long-range explosive detection.

In 1960 Atanasoff and his wife Alice moved to their hilltop farm in New Market, Maryland for their retirement.

In 1990, President George H. W. Bush awarded Atanasoff the United States National Medal of Technology, the highest U. S. honor conferred for achievements related to technological progress.

* The John Atanasoff Award, established by Georgi Parvanov in 2003 and bestowed annually by the President of Bulgaria to a young Bulgarian for achievements in the field of computer and information technologies and the information society of Bulgaria