Atanasoff-Berry Computer

The Atanasoff-Berry Computer (as it is now known; or the ABC for short) was the first-ever electronic computing device. (As Michael Williams observed, "If you add enough adjectives to a description you can always claim [a particular machine to be the 'first']"; not many adjectives are needed for this claim for the ABC!) It was not general-purpose, though; it was intended only to solve large systems of simultaneous, linear equations

Like Charles Babbage's Engines, it was digital (unlike the differential analyzers, which were the principal computing devices produced and used before the ABC). Internally, it was a parallel binary device; in physical instantiation, it was built out of vacuum tubes, about 300 tubes in total

It was designed and built by John Vincent Atanasoff, with the assistance of his student Clifford Berry (hence the name). Construction of a working prototype (to explore and demonstrate the basic approach) began in the fall quarter of 1939; that was working by December. Soon thereafter, work on the full machine began.

It is notable principally as a direct inspiration for the later ENIAC, the first-ever general-purpose electronic computing device (although the ENIAC was decimal internally, not binary, and serial, not parallel). John Mauchly, one of the two people most responsible for the ENIAC, spent several days studying the ABC in detail, in person, in June, 1941, about a year before he started on the ENIAC (in about August, 1942). This fact later led to the Atanasoff-Mauchly controversy, and the overturning of the over-broad patent on the ENIAC, in a celebrated trial in 1973.

It is also significant for being the first digital electronic computing device to use capacitor-based memory using refresh - an approach to memory now ubiquitous in the dynamic RAM of all modern computers. This capacitor-based system was effectively the ABC's main memory.

Although it was built, did operate, and solved some small problems, it never operated at full scale, for several reasons: principally because its secondary storage system (which used punched cards, with holes produced with electric arcs), used for holding intermediate results, was not yet reliable when WWII drew its creators away from Iowa State College, where it was built.

Further reading

• John V. Atanasoff, Computing Machine for the Solution of large Systems of Linear Algebraic Equations, re-printed in Brian Randell (editor), The Origins of Digital Computers: Selected Papers, Springer-Verlag, Berlin, Heidelberg, New York, 1973, 1982 (3rd edition)
• John V. Atanasoff, Advent of Electronic Digital Computing, Annals of the History of Computing, Vol. 6, No. 3, July 1984
• R. K. Richard, Electronic Digital Systems, John Wiley, New York, 1966 - the work which initially brought the ABC to the world's attention
• Alice Rowe Burks, Arthur W. Burks, The First Electronic Computer: The Atanasoff Story, University of Michigan, Ann Arbor, 1988
• Clark R. Mollenhoff, Atanasoff: Forgotten Father of the Computer, Iowa State Press, Ames, 1988

External links

• manual for the ABC
• Atanasoff Berry Computer - Operation/Purpose
  • ABC Reconstruction, 1994-1997
  • Documenting the ABC Replica Project and its Contributors
• Chapter 5: Faster, Faster: The ENIAC, in Paul E. Ceruzzi, Reckoners: The Prehistory of The Digital Computer, From Relays to the Stored Program Concept, 1935-1945, Greenwood, Westport, 1983
• Paul E. Ceruzzi, Chapter Seven: Electronic Calculators, in William Aspray (editor), Computing Before Computers, Iowa State University Press, Ames, 1990
• Reconstruction of the Atanasoff-Berry Computer
• Construction of the first electronic digital computer
• The Atanasoff-Berry-Computer - Notes