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Atanosoff Berry Computer - ABC

1935 USA


berry1.jpg (62865 bytes)











berry2_small.jpg (3749 bytes) Berry at front of ABC computer
artist view of the ABC Artist view of ABC computer
atanasoff-berry_computer Detail of memory of ABC computer


Beginning in 1935, John Vincent Atanasoff, a physics professor at Iowa State College, pioneered digital electronics for calculating. His students were working with linear partial differential equations, and he experimented with analog, then digital calculators to aid in their solution.

"I tried again and again to sort these concepts out. Nothing seemed to work. After months of work and study I went to the office again one evening but it looked as if nothing would happen. I was extremely distraught. Then I got in my automobile and started to drive. I drove hard so I would have to give my attention to driving and I wouldn't have to worry about my problems.

"When I finally came to earth I was crossing the Mississippi River, 189 miles from my desk. You couldn't get a drink in Iowa in those days, but I was crossing into Illinois. I looked ahead and there was a light and, of course, it was a tavern. I went in and got a drink, and then I noticed that my mind was very clear and sharp. I knew what I wanted to think about and I went right to work on it and worked for 3 hours, and then got in my car and drove slowly back to Ames.

"I had made four decisions in that evening at the Illinois road house: use electricity and electronics - that meant vacuum tubes in those days; use base 2, in spite of custom, for economy; use condensers, but regenerate to avoid lapses; compute by direct action, not by enumeration."

Atanasoff built this simple model of the ABC to demonstrate his concepts of digital computation. The number stored in one of the capacitor drums is added to or subtracted from the number stored in the other drum. (On loan from J. V. Atanasoff, X12.80.)

John Vincent Atanasoff, Pioneer Computer Lecture, at The Computer Museum, November 11, 1980

Professor Atanasoff lecturing to students at Iowa State University in the late 1930s.

Atanasoff and graduate student Clifford Berry built a prototype ABC (Atanasoff-Berry Computer) in 1939, and a full-scale model in 1942. Like the Bell Labs Model I, the ABC was not a computer in the modern sense, since it lacked program control and was not general purpose.

The ABC was the first of several proposals to use electronics for calculation or logic in the decade after Atanasoff began investigations in 1935. Other projects and proposals included those of Bush and Crawford both at M.I.T; Zuse and Schreier in Berlin; the British foreign office; Rajchman at R.C.A. The makers of the ENIAC, the first electronic computer, were familiar with Atanasoff's and Rajchman's work. The degree to which the ABC influenced the ENIAC design is still being debated by participants and historians.








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