Hardware Reference
In-Depth Information
a military secret for 30 years, the COLOSSUS line was basically a dead end. It is
worth noting only because it was the world's first electronic digital computer.
In addition to destroying Zuse's machines and stimulating the construction of
the COLOSSUS, the war also affected computing in the United States. The army
needed range tables for aiming its heavy artillery. It produced these tables by hir-
ing hundreds of women to crank them out using hand calculators (women were
thought to be more accurate than men). Nevertheless, the process was time con-
suming and errors often crept in.
John Mauchley, who knew of Atanasoff's work as well as Stibbitz', was aware
that the army was interested in mechanical calculators. Like many computer scien-
tists after him, he put together a grant proposal asking the army for funding to
build an electronic computer. The proposal was accepted in 1943, and Mauchley
and his graduate student, J. Presper Eckert, proceeded to build an electronic com-
puter, which they called the
ENIAC
(
Electronic Numerical Integrator And
Computer
). It consisted of 18,000 vacuum tubes and 1500 relays. The ENIAC
weighed 30 tons and consumed 140 kilowatts of power. Architecturally, the ma-
chine had 20 registers, each capable of holding a 10-digit decimal number. (A dec-
imal register is very small memory that can hold one number up to some maximum
number of decimal digits, somewhat like the odometer that keeps track of how far
a car has traveled in its lifetime.) The ENIAC was programmed by setting up 6000
multiposition switches and connecting a multitude of sockets with a veritable for-
est of jumper cables.
The machine was not finished until 1946, too late to be of any use for its origi-
nal purpose. However, since the war was over, Mauchley and Eckert were allowed
to organize a summer school to describe their work to their scientific colleagues.
That summer school was the beginning of an explosion of interest in building large
digital computers.
After that historic summer school, many other researchers set out to build elec-
tronic computers. The first one operational was the EDSAC (1949), built at the
University of Cambridge by Maurice Wilkes. Others included the JOHNNIAC at
the Rand Corporation, the ILLIAC at the University of Illinois, the MANIAC at
Los Alamos Laboratory, and the WEIZAC at the Weizmann Institute in Israel.
Eckert and Mauchley soon began working on a successor, the
EDVAC
(
Elec-
tronic Discrete Variable Automatic Computer
). However, that project was
fatally wounded when they left the University of Pennsylvania to form a startup
company, the Eckert-Mauchley Computer Corporation, in Philadelphia (Silicon
Valley had not yet been invented). After a series of mergers, this company became
the modern Unisys Corporation.
As a legal aside, Eckert and Mauchley filed for a patent claiming they invented
the digital computer. In retrospect, this would not be a bad patent to own. After
years of litigation, the courts decided that the Eckert-Mauchley patent was invalid
and that John Atanasoff invented the digital computer, even though he never
patented it, effectively putting the invention in the public domain.
