History of computing

The earliest reference of the term computer comes from the French word of the same in 1631, derived from the Latin word computare meaning "to count, to sum up". The word is formed from the two roots: com- meaning "with", and +putare meaning "to reckon"(originally "to prune").

Early Methods of Counting (300 - 1400 A.D.)

Before the arrival of mechanical or analogue computing, ancient civilizations required methods to quantify properties of their livelihoods. Circa 300 B.C., the Slamis Tablet, discovered on the island of Salamis in 1846, was used by the Babylonians to track numbers in their society. On this board, physical markers(indicators) were placed on the various rows or columns that represented different values. The indicators were not physically attached to the board.

Development of counting techniques lead to devices like the Roman hand abacus, which is estimated to have been created some time between 300 B.C. and 500 A.D. A notworthy advancement of the hand abacus was the implementation of permanently attached markers, which are adjusted in position to indicate value. This modification might have contributed to the evolution of the suan-pan, or Chinese abacus, in or around 1200 A.D., that closely resembles the abacus of today.

In the typical modern-day abacus, slidable markers are placed on columns of shafts(typically made from wood or metal) representing powers of ten (.0001, .001, .01, .1, 1, 10, 100 etc), with the top row representing values of "fives" and the bottom representing values of "ones". These markers are permanently attached to the device.

It should be noted that usage of an abacus relies on a concept of "states"; that is whether or not beads are in the "inclusive" or "not-inclusive" positions. To count items on an abacus, a number of beads are shifted over to the represented position that indicates a counted value, and any that are not moved are not counted.

Early Mechanical Computation (1500 - 1900 A.D.)

On 13 February 1967, the "Codex Madrid", written by Leonardo Da Vinci, was discovered in the National Library of Spain in Madrid. Inside the Codex Madrid was a drawing for an elaborate mechanical computational device, found by Dr. Roberto Guatelli, who noted that a similar construct appeared in Da Vinci's "Codex Atlanticus". A prototype of this machine was created in 1968, and was observed that it exhibited traits that of a ratio machine. One revolution of the first shaft(10^1) invoked ten revolutions of the second(10^2), repeating until the last shaft which rotated at a rate of ten to the power of 13.

Whether this was a true computational device was under some debate. Previously been displayed at IBM, the exhibit was removed due to a nonconsensus, and is presumed to be in one of IBM's storage facilities.

The earliest recognized mechanical computational device is the Pascaline, created by Blaise Pascal circa 1642. The Pascaline performed simple addition and subtraction.

Charles Babbage (1791-1871)

Charles Babbage (1791-1871), an English inventor who taught mathematics at Cambridge University, invented a viable mechanical computer equivalent to modern digital computers.

Invention of the vacuum tube (1906)

A necessary precursor to the first electronic computers was the invention of the switching vacuum tube, credited to Lee de Forest in 1906. The ability of vacuum tubes to act as switches (on/off devices that stop or start an electric current) would later be important in the building of the first electronic computers.

The first electronic computers

ENIAC (1946)

John Mauchly and J. Presper Eckert of the University of Pennsylvania proposed the ENIAC (Electrical Numerical Integrator and Computer) to the U.S. Army Ordnance Department's Ballistics Research Laboratory in 1943, and then served as its main designers until construction was finished in 1946. It was a military project justified by a need to compute ballistic trajectories, and was one of the earliest general-purpose, programmable electronic computers.

External links

• The Computer History Museum
• Charles Babbage Institute: Center for History of Information Technology at the University of Minnesota