Beginnings of a revolution - The Computing Universe: A Journey through a Revolution - page 18

Code breakers and bread makers

No history of the early days of computing would be complete
without recounting the pioneering work of the British cryptologists at
Bletchley Park and the development of the first computer dedicated to
business use.

Fig. 1.19 Memorial to Polish code breakers
at Bletchley Park. Their contribution was
critical to the development of the Bombe
machines used to break the Enigma codes.

Bletchley Park, Enigma, and Colossus

During World War II, British mathematicians and scientists had
been looking to automated machines for their top-secret work on code
breaking at Bletchley Park. Both Turing and his Cambridge mentor Max
Newman ( B.1.7 ) were intimately involved in designing and building auto-
mated machines to assist in decrypting secret German military com-
munications. Turing was involved in deciphering messages encrypted
using the famous Enigma machine. With a head start given to them by
Polish Intelligence ( Fig. 1.19 ), Turing helped develop electromechanical
machines, known as bombes , which were used to determine the settings of
the Enigma machine. These machines were operational as early as 1940
and contributed greatly to protecting convoys from U-boats in the North
Atlantic.
The German High Command
in Berlin used an even more com-
plex cipher machine called Lorenz.
Newman's team built a machine -
called Heath Robinson after a pop-
ular cartoonist who drew eccentric
machines - that showed it was possible to make a device to break
the Lorenz codes. This was followed by the ULTRA project to build an
all-electronic version of Heath Robinson called Colossus ( Fig. 1.20 ).
Although this machine was certainly not a general-purpose computer,
it had 1,500 vacuum tubes as well as tape readers with optical sensors
capable of processing five thousand teleprinter characters a second. The
machine was designed and built by Tommy Flowers ( B.1.8 ), an engineer
at the U.K. Post Office's Dollis Hill research laboratory in London, and
became operational in December 1943, more than two years before the
ENIAC. One of the great achievements of Colossus was reassuring the
Allied generals, Eisenhower and Montgomery, that Hitler had believed
the deception that the D-Day invasion fleet would come from Dover.
The immense contribution of code breakers was recognized by Winston
Churchill when he talked about “the Geese that laid the golden eggs but
never cackled.” 17

Fig. 1.20 A photograph of the Colossus
computer, the code-breaking machine
that nobody knew existed until many
years after the war. It was designed and
built by Tommy Flowers, an engineer at
the British Post Office in 1943.

B.1.7 Max Newman (1897-1984) was a
brilliant Cambridge, U.K., mathemati-
cian and code breaker. It was Newman's
lectures in Cambridge that inspired
Alan Turing to invent his famous Turing
Machine. Newman was at Bletchley Park
during World War II and his team was
working on the messages encrypted by
the Lorenz cipher machine. They built
a machine - called Heath Robinson - to
break the Lorenz code, and this was later
automated as the Colossus computer.

The main task for the code breakers was to read the text from a paper
tape and to work out the possible settings of the twelve rotors of the
encrypting device. Colossus was first demonstrated in December 1943