Information Technology Reference
In-Depth Information
Note
Grace Hopper's military career was in the Navy Reserve rather than
the regular Navy. She was promoted to Rear Admiral in 1985 and
at the time of her retirement in 1986, she was the oldest serving
naval officer at age 79. She was a polymath who made great con-
tributions to software and computer engineering. I had the honor of
attending one of her speeches just before her retirement. She was
an excellent public speaker as well as a brilliant inventor and ad-
ministrator.
As examples of why early computers were expensive, the Harvard Mark I had
500 miles of wire and more than 3,000,000 soldered connections.
The Mark I was followed by other Aiken designs called the Mark II, Mark III,
and Mark IV. None of these should be confused with the British Mark I designed
in Manchester, which became operational in 1948.
Aiken caused hard feelings at IBM by announcing the Mark I as his sole in-
vention and for failing to name any of the IBM designers and builders other than
James Bryce. This annoyed the IBM Chairman, Thomas J. Watson, and led to IBM
moving in a different direction.
The direction IBM selected was to build the IBM Selective Sequence Electron-
ic Calculator (SSEC), The design of the SSEC started in 1944, but the machine
was not completed until 1947. The SSEC was the very last electromechanical
computer completed. After it, all computers were purely electronic.
Wallace John Eckert of Columbia University (no relation to Presper Eckert) de-
signed the SSEC, but it was constructed at IBM Endicott under the supervision of
John McPherson using some technology by an IBM engineer, James Bryce. Fran-
cis Hamilton and Robert Seeber also contributed to the design.
The SSEC was not Turing complete and was more of a high-speed calculator
than a true computer. However, the SSEC did much to make computers known to
the general public. The SSEC was installed in New York near IBM and was loc-
ated in a former shoe store with a plate-glass window that allowed passersby to
see the machine.
The SSEC was a large and impressive machine; because it was going on public
display, it was designed to look impressive. The SSEC started a trend of glass-
wall, raised-floor computer rooms, which hundreds of companies imitated to show
Search WWH ::
Custom Search