History of
Computers
The
first computers were people! That is, electronic computers (and the earlier
mechanical computers) were given this name because they performed the work that
had previously been assigned to people. "Computer" was originally a
job title: it was used to describe those human beings (predominantly women)
whose job it was to perform the repetitive calculations required to compute
such things as navigational tables, tide charts, and planetary positions for
astronomical almanacs. Imagine you had a job where hour after hour, day after
day, you were to do nothing but compute multiplications. Boredom would quickly
set in, leading to carelessness, leading to mistakes. And even on your best
days you wouldn't be producing answers very fast. Therefore, inventors have
been searching for hundreds of years for a way to mechanize (that is, find a
mechanism that can perform) this task.
The
abacus was an early aid for mathematical computations. Its only
value is that it aids the memory of the human performing the calculation. A
skilled abacus operator can work on addition and subtraction problems at the
speed of a person equipped with a hand calculator (multiplication and division
are slower). The abacus is often wrongly attributed to China. In fact, the
oldest surviving abacus was used in 300 B.C. by the Babylonians. The abacus is
still in use today, principally in the far east. A modern abacus consists of
rings that slide over rods, but the older one pictured below dates from the
time when pebbles were used for counting (the word "calculus" comes
from the Latin word for pebble).
In
1617 an eccentric (some say mad) Scotsman named John Napier invented logarithms,
which are a technology that allows multiplication to be performed via addition.
The magic ingredient is the logarithm of each operand, which was originally
obtained from a printed table. But Napier also invented an alternative to
tables, where the logarithm values were carved on ivory sticks which are now
called Napier's Bones.
Napier's
invention led directly to the slide rule, first built in England
in 1632 and still in use in the 1960's by the NASA engineers of the Mercury, Gemini,
and Apollo programs which landed men on the moon.
Leonardo
da Vinci (1452-1519) made drawings of gear-driven calculating machines but
apparently never built any.
The
first gear-driven calculating machine to actually be built was probably the calculating
clock, so named by its inventor, the German professor Wilhelm Schickard
in 1623. This device got little publicity because Schickard died soon afterward
in the bubonic plague.
In
1642 Blaise Pascal, at age 19, invented the Pascaline as an aid
for his father who was a tax collector. Pascal built 50 of this gear-driven
one-function calculator (it could only add) but couldn't sell many because of
their exorbitant cost and because they really weren't that accurate (at that
time it was not possible to fabricate gears with the required precision). Up
until the present age when car dashboards went digital, the odometer portion of
a car's speedometer used the very same mechanism as the Pascaline to increment
the next wheel after each full revolution of the prior wheel. Pascal was a
child prodigy. At the age of 12, he was discovered doing his version of
Euclid's thirty-second proposition on the kitchen floor. Pascal went on to
invent probability theory, the hydraulic press, and the syringe. Shown below is
an 8 digit version of the Pascaline, and two views of a 6 digit version:
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