History
Main articles: History of computing and History of computing hardware
For a chronological guide, see Timeline of computing.
Pre-20th century
The Ishango bone, a bone tool dating back to prehistoric Africa
Devices have been used to aid computation for thousands of years, mostly
using one-to-one correspondence with fingers. The earliest counting device was
most likely a form of tally stick. Later record keeping aids throughout the Fertile
Crescent included calculi (clay spheres, cones, etc.) which represented counts of
items, likely livestock or grains, sealed in hollow unbaked clay containers.[a][4] The use
of counting rods is one example.
The Chinese suanpan (算盘). The number represented on
this abacus is 6,302,715,408.
The abacus was initially used for arithmetic tasks. The Roman abacus was
developed from devices used in Babylonia as early as 2400 BCE. Since then, many
other forms of reckoning boards or tables have been invented. In a medieval
European counting house, a checkered cloth would be placed on a table, and
markers moved around on it according to certain rules, as an aid to calculating sums
of money.[5]
The Antikythera mechanism, dating back to ancient
Greece circa 200–80 BCE, is an early analog computing device.
The Antikythera mechanism is believed to be the earliest known mechanical analog
computer, according to Derek J. de Solla Price.[6] It was designed to calculate
astronomical positions. It was discovered in 1901 in the Antikythera wreck off the
Greek island of Antikythera, between Kythera and Crete, and has been dated to
approximately c. 100 BCE. Devices of comparable complexity to the Antikythera
mechanism would not reappear until the fourteenth century.[7]
Many mechanical aids to calculation and measurement were constructed for
astronomical and navigation use. The planisphere was a star chart invented by Abū
Rayhān al-Bīrūnī in the early 11th century.[8] The astrolabe was invented in
the Hellenistic world in either the 1st or 2nd centuries BCE and is often attributed
to Hipparchus. A combination of the planisphere and dioptra, the astrolabe was
effectively an analog computer capable of working out several different kinds of
problems in spherical astronomy. An astrolabe incorporating a
mechanical calendar computer[9][10] and gear-wheels was invented by Abi Bakr
of Isfahan, Persia in 1235.[11] Abū Rayhān al-Bīrūnī invented the first mechanical
geared lunisolar calendar astrolabe,[12] an early fixed-wired knowledge processing
machine[13] with a gear train and gear-wheels,[14] c. 1000 AD.
The sector, a calculating instrument used for solving problems in
proportion, trigonometry, multiplication and division, and for various functions, such
as squares and cube roots, was developed in the late 16th century and found
application in gunnery, surveying and navigation.
The planimeter was a manual instrument to calculate the area of a closed figure by
tracing over it with a mechanical linkage.
A slide rule
The slide rule was invented around 1620–1630, by the English clergyman William
Oughtred, shortly after the publication of the concept of the logarithm. It is a hand-
operated analog computer for doing multiplication and division. As slide rule
development progressed, added scales provided reciprocals, squares and square
roots, cubes and cube roots, as well as transcendental functions such as logarithms
and exponentials, circular and hyperbolic trigonometry and other functions. Slide
rules with special scales are still used for quick performance of routine calculations,
such as the E6B circular slide rule used for time and distance calculations on light
aircraft.
In the 1770s, Pierre Jaquet-Droz, a Swiss watchmaker, built a mechanical doll
(automaton) that could write holding a quill pen. By switching the number and order
of its internal wheels different letters, and hence different messages, could be
produced. In effect, it could be mechanically "programmed" to read instructions.
Along with two other complex machines, the doll is at the Musée d'Art et d'Histoire
of Neuchâtel, Switzerland, and still operates.[15]
In 1831–1835, mathematician and engineer Giovanni Plana devised a Perpetual
Calendar machine, which through a system of pulleys and cylinders could predict
the perpetual calendar for every year from 0 CE (that is, 1 BCE) to 4000 CE, keeping
track of leap years and varying day length. The tide-predicting machine invented by
the Scottish scientist Sir William Thomson in 1872 was of great utility to navigation in
shallow waters. It used a system of pulleys and wires to automatically calculate
predicted tide levels for a set period at a particular location.
The differential analyser, a mechanical analog computer designed to
solve differential equations by integration, used wheel-and-disc mechanisms to
perform the integration. In 1876, Sir William Thomson had already discussed the
possible construction of such calculators, but he had been stymied by the limited
output torque of the ball-and-disk integrators.[16] In a differential analyzer, the output
of one integrator drove the input of the next integrator, or a graphing output.
The torque amplifier was the advance that allowed these machines to work. Starting
in the 1920s, Vannevar Bush and others developed mechanical differential
analyzers.
In the 1890s, the Spanish engineer Leonardo Torres Quevedo began to develop a
series of advanced analog machines that could solve real and complex roots
of polynomials,[17][18][19][20] which were published in 1901 by the Paris Academy of
Sciences.[21]
