U.S. Army
Photo
The ENIAC,
in BRL building 328
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By
Mary
Bellis
In
1946, John Mauchly and J Presper Eckert developed the ENIAC I (Electrical
Numerical
Integrator
And
Calculator).
The U.S. military sponsored their research; they needed a calculating device
for writing artillery-firing tables (the settings used for different weapons
under varied conditions for target accuracy). The Ballistics Research Laboratory,
or BRL (the branch of the military responsible for calculating the tables),
heard about John Mauchly's research at the University of Pennsylvania's
Moore School of Electrical Engineering. John Mauchly had previously created
several calculating machines, some with small electric motors inside. He
had begun designing (1942) a better calculating machine based on the work
of John Atanasoff that would use vacuum tubes
to speed up calculations.
On May 31, 1943, the military commission
on the new computer began; John Mauchly was the chief consultant and J
Presper Eckert was the chief engineer. Eckert was a graduate student studying
at the Moore School when he met John Mauchly in 1943. It took the team
about one year to design the ENIAC and 18 months and 500,000 tax dollars
to build it. By that time, the war was over. The ENIAC was still put to
work by the military doing calculations for the design of a hydrogen bomb,
weather prediction, cosmic-ray studies, thermal ignition, random-number
studies and wind-tunnel design.
The ENIAC contained 17,468 vacuum
tubes, along with 70,000 resistors, 10,000 capacitors, 1,500 relays, 6,000
manual switches and 5 million soldered joints. It covered 1800 square feet
(167 square meters) of floor space, weighed 30 tons, consumed 160 kilowatts
of electrical power. There was even a rumor that when turned on the ENIAC caused the city of Philadelphia
to experience brownouts, however, this was first reported incorrectly by the Philadelphia
Bulletin in 1946 and since then has become an urban myth.
 In
one second, the ENIAC (one thousand times faster than any other calculating
machine to date) could perform 5,000 additions, 357 multiplications or
38 divisions. The use of vacuum tubes instead of switches and relays created
the increase in speed, but it was not a quick machine to re-program. Programming
changes would take the technicians weeks, and the machine always required
long hours of maintenance. As a side note, research on the ENIAC led to
many improvements in the vacuum tube.
In 1948, Dr. John Von Neumann made
several modifications to the ENIAC. The ENIAC had performed arithmetic
and transfer operations concurrently, which caused programming difficulties.
Von Neumann suggested that switches control code selection so pluggable
cable connections could remain fixed. He added a converter code to enable
serial operation.
In 1946, J Presper Eckert and John
Mauchly started the Eckert-Mauchly Computer Corporation. In 1949, their
company launched the BINAC (BINary Automatic) computer that used magnetic
tape to store data.
In 1950, the Remington Rand Corporation
bought the Eckert-Mauchly Computer Corporation and changed the name to
the Univac Division of Remington Rand. Their research resulted in the UNIVAC
(UNIVersal Automatic Computer), an important forerunner of today's computers.
In 1955, Remington Rand merged with
the Sperry Corporation and formed Sperry-Rand. Eckert remained with the
company as an executive and continued with the company as it later merged
with the Burroughs Corporation to become Unisys.
J Presper Eckert and John Mauchly
both received the IEEE Computer Society Pioneer Award in 1980.
At 11:45 p.m., October 2, 1955, with
the power finally shut off, the ENIAC retired.
Next
Chapter > The
Manchester Baby and the Williams Tube
artwork©marybellis
original
photos©"army photos"
|
"...With the advent of everyday use
of elaborate calculations, speed has become paramount to such a high degree
that there is no machine on the market today capable of satisfying the
full demand of modern computational methods." - from the ENIAC patent (U.S.#3,120,606),
filed on June 26, 1947.
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