Hardware Reference
In-Depth Information
of Babbage's work, and his machines were destroyed by the Allied bombing of
Berlin in 1944, so his work did not have any influence on subsequent machines.
Still, he was one of the pioneers of the field.
Slightly later, in the United States, two people also designed calculators, John
Atanasoff at Iowa State College and George Stibbitz at Bell Labs. Atanasoff's ma-
chine was amazingly advanced for its time. It used binary arithmetic and had
capacitors for memory, which were periodically refreshed to keep the charge from
leaking out, a process he called ''jogging the memory.'' Modern dynamic memory
(DRAM) chips work the same way. Unfortunately the machine never really
became operational. In a way, Atanasoff was like Babbage: a visionary who was
ultimately defeated by the inadequate hardware technology of his time.
Stibbitz' computer, although more primitive than Atanasoff's, actually worked.
Stibbitz gave a public demonstration of it at a conference at Dartmouth College in
1940. Among those in the audience was John Mauchley, an unknown professor of
physics at the University of Pennsylvania. The computing world would hear more
about Prof. Mauchley later.
While Zuse, Stibbitz, and Atanasoff were designing automatic calculators, a
young man named Howard Aiken was grinding out tedious numerical calculations
by hand as part of his Ph.D. research at Harvard. After graduating, Aiken recog-
nized the importance of being able to do calculations by machine. He went to the
library, discovered Babbage's work, and decided to build out of relays the gener-
al-purpose computer that Babbage had failed to build out of toothed wheels.
Aiken's first machine, the Mark I, was completed at Harvard in 1944. It had
72 words of 23 decimal digits each and had an instruction time of 6 sec. Input and
output used punched paper tape. By the time Aiken had completed its successor,
the Mark II, relay computers were obsolete. The electronic era had begun.
The stimulus for the electronic computer was World War II. During the early
part of the war, German submarines were wreaking havoc on British ships. Com-
mands were sent from the German admirals in Berlin to the submarines by radio,
which the British could, and did, intercept. The problem was that these messages
were encoded using a device called the
ENIGMA
, whose forerunner was designed
by amateur inventor and former U.S. president, Thomas Jefferson.
Early in the war, British intelligence managed to acquire an ENIGMA machine
from Polish Intelligence, which had stolen it from the Germans. However, to break
a coded message, a huge amount of computation was needed, and it was needed
very soon after the message was intercepted to be of any use. To decode these
messages, the British government set up a top secret laboratory that built an elec-
tronic computer called the COLOSSUS. The famous British mathematician Alan
Turing helped design this machine. The COLOSSUS was operational in 1943, but
since the British government kept virtually every aspect of the project classified as
