History of computing

The invention of electronic computers may be a milestone for humanity on a par with the advent of writing and materials to write on (millennia ago), or with the invention of the printing press (~1450). This article attempts to outline some of the major milestones in the history of computing, pointing off to additional articles to fill in more detail.

Early Counting Aids (300 - 1400 A.D.)

Before the arrival of mechanical or analogue computing, ancient civilizations required methods to quantify properties of their livelihoods.

Slamis Tablet (300 B.C.)

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.

The Abacus

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" and place values; 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 computing pioneers and mechanical computers (1500 - 1900 A.D.)

Leonardo Da Vinci (1452-1519)

Leonardo Da Vinci's Codex Madrid, which has been characterized as "a densely drawn treatise on theoretical and applied mechanics", lay hidden until 1967, when it was rediscovered in the National Library of Spain in Madrid. Inside the Codex, a drawing was found for an elaborate mechanical computational device, similar to a construct found in Da Vinci's Codex Atlanticus. In 1968, a working prototype was created and exhibited by IBM, and a hot debate ensued about whether this was a true computational device. Eventually, the exhibit was removed due to a lack of consensus about its validity as a computer, or its adherence to da Vinci's intentions.

Blaise Pascal (1623–1662) and the Pascaline

Around 1642, Blaise Pascal created the earliest recognized mechanical computational device, now called the Pascaline. The Pascaline performed simple addition and subtraction. The concept of the Pascaline came about from the carrying of places by gear rotation. Functionally, the machine worked by increasing values on a single cog, which ranged from values 0 to 9. Upon the next rotation, a series of cogs would rotate the next gear over one iteration to read 1 while the first cog would reset back to 0. The Pascaline may be considered the first in a long series of mechanical adding machines which could assist humans in performing arithmetic.

Weaving machines (1800's?)

These were not general-purpose, but they could be "programmed" to implement different patterns.

Charles Babbage (1791-1871)and the Analytical Engine

Charles Babbage, an English inventor who taught mathematics at Cambridge University, invented a mechanical computer (called the Analytical Engine) that would have been roughly equivalent to modern digital computers had it ever been completed. Because his two computers never quite reached fruition, Babbage was forgotten in the decades immediately following his death. But Babbage is now recognized for being one of the first computing pioneers to imagine a general-purpose programmable computer.

Herman Hollerith (1860-1929) and punched card input

Herman Hollerith, an employee of the United States census bureau, is remembered for having created a method for inputing program instructions to computing devices by using holes punched in cards.

Prerequisites for modern 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.

Strowger switch and telephone dialing (~1920)

Telephone automation systems, called "switches" or switchboards, were likely among the first electromechanical devices to implement a primitive form of computer-like memory, whereby a number is stored by the setting of relays, or the operation of similar equipment. The earliest form of switching memory was the Strowger switch, developed by an independent American inventor decades before Bell Laboratories invented an equivalent technology. Strowger switches completed an additional segment of a phone call's connection each time a digit was dialed; in this case, the entire telephone system was the memory. Strowger eliminated the need for intervention by a human operation when placing a phone call (in consumer terms, he "invented the dial telephone"). Later switchboards (1960's generation) used general-purpose computers and completely stored all digits of the dialed number in a register before making a routing decision based on a host of complex factors. Call connections were made "all at once" after running a program that analyzed the dialed number.

Relating boolean algebra to logic gate design (1940)

Claude Shannon (1916-2001) made a critical step enabling hardware design of a computer by associating boolean algebra, a kind of mathematical system that had been known for centuries, with the design of logic gates in digital hardware. Shannon called boolean algebra "switching algebra" in the realm of computer hardware design. Shannon also later made seminal contributions towards the burgeoning field of information theory.

The first electronic computers (1940 - 1952)

During World War II, the first electronic computers were developed by the British and U. S. governments as a result of secret military projects.

Zuse V3 (1941)

Konrad Zuse, working in relative isolation in pre-war Germany, built three prototype electronic computers (V1, V2 and V3) which computed using the binary number system and other advanced design concepts. His third model, the Z3, was completed in 1941, well before any of the computers shown below. Unfortunately, all three of his working models were destroyed during World War II. After the war, Zuse built another computer in Switzerland (the V4), and later was the first designer to propose pipelining the computations of a computer processor.

Atanasoff-Berry computer (1942)

John Atanasoff and graduate student Clifford Berry, of Iowa State University, worked on a prototype electronic computer between 1937 and 1942 . Their work introduced key design ideas which may have been communicated from Atanasoff to John Mauchly, who later may have incorporated them into the design of the better-known ENIAC computer. Some people give Atanasoff credit for creating the very first working electronic computer, although most historic attention has focused on the ENIAC as being the first.

Colossus (1943)

The highly secret, military Colossus project produced a series of about ten electronic computers used by British codebreakers to read encrypted German messages during World War II. The Colossus computers used the binary number system for computation. The Colossus prototype was initially completed by engineer Tommy Flowers in 1943 at the Post Office Research Station, Dollis Hill, with input from mathematician Max Newman and a few others. The project moved to Bletchley Park by 1944 and lasted until the end of the war.

Harvard Mark I (1943)

The idea for the Mark I computer was conceived in the 1930's by Howard Aiken, then a graduate student in theoretical physics at Harvard University, and who obtained his Ph. D. from Harvard in 1939. The computer was developed and built by International Business Machines (IBM). in 1943 at Harvard. It used the decimal number system for computation, as well as mechanical, punch-card input equipment developed by IBM. The Mark I remained in use until 1959, although by that time its performance was far surpassed by the newer 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. ENIAC used the decimal number system, instead of the binary number system used by most subsequent digital computers. Also, ENIAC was not yet able to store its own program in memory. It had to be programmed by setting switches on function tables and by changing the wiring; considerable human effort was required to reprogram it.

UNIVAC (1951)

The designers of ENIAC jointly formed the Eckert-Mauchly Computer Corporation in 1946, which was bought by Remington Rand in 1950. In 1951, this company delivered the first U. S. commercial computer, called the UNIVAC, to the United States Census Bureau. It was a stored-program computer, like its non-commercial sister the EDVAC. Competing fiercely with IBM, the company eventually built 46 of the earliest commercial computer systems.

EDVAC (1952)

The EDVAC (Electronic Discrete Variable Automatic Computer) was a successor to ENIAC, intended to resolve some design difficulties. It was the first internally stored program computer to be built, a major improvement over the ENIAC. The U.S. Army Ballistics Research Laboratory funded the development of EDVAC, and it was built at the Aberdeen Proving Ground by the University of Pennsylvania, including ENIAC designers Eckert & Mauchly. They were joined on the EDVAC design by John von Neumann and some others. The EDVAC realized the stored-program concept first published in von Neumann's 1945 report First Draft of a Report on the EDVAC. Although its design predates the UNIVAC, the EDVAC did not become fully operational until 1952.

Key people in history of computing

For now, see this list of people who made conceptual breakthroughs in computer science.

Key concepts in history of computing

For now, see this list of seminal concepts in computer science.

External links

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