Electronic Numerical Integrator and Computer
Electronic Numerical Integrator and Computer
(computer)In 1940 Dr. John Vincent Atanasoff attended a lecture byMauchly and subsequently agreed to show him his binarycalculator, the Atanasoff-Berry Computer (ABC), which waspartially built between 1937-1942. Mauchly used ideas fromthe ABC in the design of ENIAC, which was started in June 1943and released publicly in 1946.
ENIAC was not the first digital computer, Konrad Zuse's Z3was released in 1941. Though, like the ABC, the Z3 waselectromechanical rather than electronic, it was freelyprogrammable via paper tape whereas ENIAC was onlyprogrammable by manual rewiring or switches. Z3 used binaryrepresentation like modern computers whereas ENIAC useddecimal like mechanical calculators.
ENIAC was underwritten and its development overseen byLieutenant Herman Goldstine of the U.S. Army BallisticResearch Laboratory (BRL). While the prime motivation forconstructing the machine was to automate the wartimeproduction of firing and bombing tables, the very firstprogram run on ENIAC was a highly classified computationfor Los Alamos. Later applications included weatherprediction, cosmic ray studies, wind tunnel design,petroleum exploration, and optics.
ENIAC had 20 registers made entirely from vacuum tubes.It had no other no memory as we currently understand it. Themachine performed an addition in 200 microseconds, amultiplication in about three milliseconds, and a divisionin about 30 milliseconds.
John von Neumann, a world-renowned mathematician serving onthe BRL Scientific Advisory Committee, soon joined thedevelopers of ENIAC and made some critical contributions.While Mauchly, Eckert and the Penn team continued on thetechnological problems, he, Goldstine, and others took up thelogical problems.
In 1947, while working on the design for the successormachine, EDVAC, von Neumann realized that ENIAC's lack of acentral control unit could be overcome to obtain a rudimentarystored program computer (see the Clippinger reference below).Modifications were undertaken that eventually led to aninstruction set of 92 "orders". Von Neumann also proposedthe fetch-execute cycle.
[R. F. Clippinger, "A Logical Coding System Applied to theENIAC", Ballistic Research Laboratory Report No. 673, AberdeenProving Ground, MD, September 1948.http://ftp.arl.mil/~mike/comphist/48eniac-coding].
[H. H. Goldstine, "The Computer from Pascal to von Neumann",Princeton University Press, 1972].
[K. Kempf, "Electronic Computers within the Ordnance Corps",Aberdeen Proving Ground, MD, 1961.http://ftp.arl.mil/~mike/comphist/61ordnance].
[M. H. Weik, "The ENIAC Story", J. American Ordnance Assoc.,1961. http://ftp.arl.mil/~mike/comphist/eniac-story.html].