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In 1946, John Mauchly and John 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 heard about
John Mauchly's research at the University of Pennsylvania's
Moore School of Electrical Engineering. Mauchly had previously
created several calculating machines, some with small electric
motors inside. In 1942 he had begun designing a better
calculating machine based on the work of John Atanasoff, which
would use vacuum tubes to speed up calculations.
On May 31, 1943, the military commission on the new computer
began; Mauchly was the chief consultant and 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 of floor space, weighed 30 tons, consumed 160 kilowatts of
electrical power, and, when turned on, caused the city of
Philadelphia to experience brownouts.
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 technician’s 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, Eckert and Mauchly started the Eckert-Mauchly
Computer Corporation. In 1949, their company launched the BINAC
(BINary Automatic) computer that used magnetic tape to store
data. |
