Beginnings of a revolution - The Computing Universe: A Journey through a Revolution - page 11

Some early history of computing

An idea long in the making

While the origins of the modern electronic computer can be traced back to EDVAC in the 1940s, the
idea of powerful computational machines goes back much further, to the early nineteenth century and an
Englishman named Charles Babbage.

Charles Babbage and the Difference Engine

The first government-funded computer project to overrun its budget was Charles Babbage's attempt
to construct his Difference Engine in 1823. The project had its origins in the problem of errors in the math-
ematical tables of the navigator's bible , the British Nautical Almanac. These errors, either from mistakes in
calculation or from copying and typesetting, plagued all such tables and were popularly supposed to be
the cause of numerous shipwrecks. One study of a random selection of forty volumes of tables found three
thousand errors listed on correction or errata sheets. Some sheets were even correction sheets for earlier
corrections!
Charles Babbage ( B.1.4 ) was a mathematician and a student at Cambridge University in 1812 when he
first had the idea of using a machine to calculate mathematical tables. He wrote about the moment in his
autobiography:

One evening I was sitting in the rooms of the Analytical Society, at Cambridge,
my head leaning forward on the table in a kind of dreamy mood, with a
table of logarithms lying open before me. Another member, coming into
the room, and seeing me half asleep called out “Well, Babbage, what are
you dreaming about?” to which I replied, “I am thinking that all these tables
(pointing to the logarithms) might be calculated by machinery.” 9

Some years later Babbage was checking astronomical tables with his
astronomer friend John Herschel. They each had a pile of papers in front
of them containing the results for the tables as calculated by “computers.”
In those days, computers were not machines but people who had been
given a precise arithmetical procedure to do the routine calculations by
hand. The two piles contained the same set of calculations, each done
by different computers but both should be identical. By comparing the
results line by line Babbage and Herschel found a number of errors and
the whole process was so slow and tedious that Babbage finally exclaimed
“I wish to God these calculations had been executed by steam.” 10
As a result of his experience, Babbage spent the next few years
designing what he called the Difference Engine - a mechanical machine
that was able to calculate astronomical and navigational tables using a
mathematical process called the method of constant differences. Correct
calculations were only part of the problem however, since the copying and
typesetting of the results were equally error prone. In order to eliminate
these errors, Babbage designed his machine to record the results on metal
plates that could be used directly for printing. By 1822 he had built a small
working prototype and made a proposal to the Royal Society that a large,

B.1.4 Charles Babbage (1792-1871) was
the son of a wealthy banker. He studied
mathematics at Cambridge and was the
leader of a radical group of students
that overthrew the negative legacy of
Isaac Newton's approach to calculus on
mathematics in England by introduc-
ing new notation and mathematical
techniques from France and Germany.
Babbage is now known for his pioneer-
ing work in computing, but he was also
a prolific inventor. Among other things,
he invented the ophthalmoscope, a
cowcatcher, the seismograph, and a
submarine propelled by compressed air.
However, Babbage's computing engines
were never completed, and he died a
disappointed man.