<computer> (ABC) An early design for a binary calculator, one of the predecessors of the digital computer. The ABC was partially constructed between 1937 and 1942 by Dr. {John Vincent Atanasoff} and Clifford Berry at Iowa State College. As well as binary arithmetic, it incorporated {regenerative memory}, parallel processing, and separation of memory and computing functions. The electronic parts were mounted on a rotating drum, making it hybrid electronic/electromechanical. It was designed to handle only a single type of mathematical problem and was not automated. The results of a single calculation cycle had to be retrieved by a human operator, and fed back into the machine with all new instructions, to perform complex operations. It lacked any serious form of logical control or conditional statements. Atanasoff's patent application was denied because he never have a completed, working product. Ideas from the ABC were used in the design of ENIAC (1943-1946). http://cs.iastate.edu/jva/jva-archive.shtml. (2003-09-28)

The Atanasoff–Berry computer (ABC) was the first automatic electronic digital computer. Limited by the technology of the day, and execution, the device has remained somewhat obscure. The ABC's priority is debated among historians of computer technology, because it was neither programmable, nor Turing-complete. Conventionally, the ABC would be considered the first electronic ALU (arithmetic logic unit) – which is integrated into every modern processor's design.

Its unique contribution was to make computing faster by being the first to use vacuum tubes to do the arithmetic calculations. Prior to this, slower electro-mechanical methods were used by Konrad Zuse's Z1, and the simultaneously developed Harvard Mark I. The first electronic, programmable, digital machine, the Colossus computer from 1943 to 1945, used similar tube-based technology as ABC.

Sara Sweezy Berry (born 1940) is an American scholar of contemporary African political economies, professor of history at Johns Hopkins Universityhttp://www.ipc-undp.