Electronic Numerical Integrator and Computer
ENIAC
(ENIAC) The first electronic digital computer and
an ancestor of most computers in use today. ENIAC was
developed by Dr. John Mauchly and J. Presper Eckert during
World War II at the Moore School of the University of
Pennsylvania.
In 1940 Dr. John Vincent Atanasoff attended a lecture by
Mauchly and subsequently agreed to show him his binary
calculator, the Atanasoff-Berry Computer (ABC), which was
partially built between 1937-1942. Mauchly used ideas from
the ABC in the design of ENIAC, which was started in June 1943
and released publicly in 1946.
ENIAC was not the first digital computer, Konrad Zuse's Z3
was released in 1941. Though, like the ABC, the Z3 was
electromechanical rather than electronic, it was freely
programmable via paper tape whereas ENIAC was only
programmable by manual rewiring or switches. Z3 used binary
representation like modern computers whereas ENIAC used
decimal like mechanical calculators.
ENIAC was underwritten and its development overseen by
Lieutenant Herman Goldstine of the U.S. Army Ballistic
Research Laboratory (BRL). While the prime motivation for
constructing the machine was to automate the wartime
production of firing and bombing tables, the very first
program run on ENIAC was a highly classified computation
for Los Alamos. Later applications included weather
prediction, 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. The
machine performed an addition in 200 microseconds, a
multiplication in about three milliseconds, and a division
in about 30 milliseconds.
John von Neumann, a world-renowned mathematician serving on
the BRL Scientific Advisory Committee, soon joined the
developers of ENIAC and made some critical contributions.
While Mauchly, Eckert and the Penn team continued on the
technological problems, he, Goldstine, and others took up the
logical problems.
In 1947, while working on the design for the successor
machine, EDVAC, von Neumann realized that ENIAC's lack of a
central control unit could be overcome to obtain a rudimentary
stored program computer (see the Clippinger reference below).
Modifications were undertaken that eventually led to an
instruction set of 92 "orders". Von Neumann also proposed
the fetch-execute cycle.
[R. F. Clippinger, "A Logical Coding System Applied to the
ENIAC", Ballistic Research Laboratory Report No. 673, Aberdeen
Proving 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>].
[How "general purpose" was ENIAC, compared to Zuse's Z3?]
(2003-10-01)
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