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Who invented the computer?

Sometimes called "Napier's bones", this manually-operated calculating device was created by Scottish scientist John Napier of...Read More >>Sometimes called "Napier's bones", this manually-operated calculating device was created by Scottish scientist John Napier of Merchiston (1550–1617) for multiplication and division.There is no simple answer to this question, because the definition of what a computer actually is has changed over the years. The first mechanical computer, which was created by British inventor Charles Babbage in 1822, would not be what most people would think of as a computer today. Generally speaking, a computer is a device that can be instructed to carry out a set of arithmetical operations automatically. This set of operations is called a program. Most modern computers in use nowadays are digital electronic computers. But in the past, before electronic components were invented, computers were mechanical devices. Later mechanical computers were powered by electricity and were known as electro-mechanical computers.

The Antikythera mechanism

Antikythera mechanism

The Antikythera mechanism is the earliest known mechanical "computer”. Designed and built by Greek scientists between 200 and 100 BC, it was used to calculate astronomical positions. Recovered in 1901 from a shipwreck off the Greek island of Antikythera, the device has a clockwork mechanism consisting of at least 30 meshing bronze gear wheels housed inside a wooden box about the size of a shoebox. The gears ran a system that displayed the date, the positions of the Sun and Moon, the phases of the Moon, a 19-year calendar and a 223-month eclipse prediction dial. 


Jaquet-Droz automata. From left to right: The Draughtsman, The Musician, The Writer Rama

Jaquet-Droz automata

In the 1770s, Swiss watchmaker Pierre Jaquet-Droz (1721–90), built a set of mechanical dolls, or automata. One, called The Writer, could write holding a quill pen. It could be mechanically "programmed" to carry out instructions: if the number and order of their internal wheels were switched around, the pen could write different letters and therefore different messages. The wheels formed a programmable memory. The automata, housed at the Musée d'Art et d'Histoire in Neuchâtel, Switzerland, still work today.


Drawing of part of Babbage's Difference engine 

Babbage's Difference engine

British mathematician Charles Babbage (1791–1871) is considered by many to be the "father of the computer”. He invented the first mechanical computer in the early 19th century. In 1823, he directed the building of the steam-powered Difference Engine, which could perform mathematical calculations to astronomical positions (for use in navigation). This machine, along with later versions of it, remained unfinished at Babbage's death. Although entirely mechanical, the basic design had similarities with a modern computer: the data and program memory were separated and the operation was instruction-based.

Babbage's design for the Difference Engine was finally built in 1989–1991, following his plans. It performed its first...Read More >>Babbage's design for the Difference Engine was finally built in 1989–1991, following his plans. It performed its first calculation at the London Science Museum.


Punch cards for the Analytical Engine

Analytical Engine

Another of Babbage's inventions, the more complex Analytical Engine, was a device intended to be able to perform calculations using punched cards that would submit instructions. It was to have a memory unit that could store numbers—fundamental components of today's computers. First described in 1837, the Engine was never built, but remained as a series of designs.

Ada Lovelace is often described today as the world's first computer programmer. Impressed by her analytical skills, Babbage...Read More >>Ada Lovelace is often described today as the world's first computer programmer. Impressed by her analytical skills, Babbage called her "The Enchantress of Numbers".Babbage received help with development of his machines from British mathematician Ada Lovelace (1815–52). Lovelace showed that computers could perform much more elaborate functions than simply making mathematical calculations. She demonstrated this by completing a program for the Analytical Engine, a method for calculating a certain mathematical sequence. Lovelace is often described today as the world's first computer programmer.

Alan Turing, aged 16

Turing machine

The principle of the modern computer was proposed by English mathematician and computer scientist Alan Turing (1912–54) in 1936. He proposed—though never built—a simple device that he called a ”Universal Computing machine”, now known as a “Turing machine”. This demonstrated how computers could work, and is now considered the model on which all modern computers are based. Fundamental to his design was the stored program, in which all the instructions for computing are held in memory.


A copy of the Zuse Z3

Konrad Zuse

The Z1 was created by German engineer Konrad Zuse (1910–95) in his parents' living room between 1936 and 1938. It is now considered the first functional modern computer (although it never worked well). In 1941, Zuse developed the Z3, the world's first working electro-mechanical, programmable, fully automatic digital computer. He went on to found one of the earliest computer businesses in 1941, producing the Z4, which became the world's first commercial computer. Living in Nazi Germany, Zuse carried out his work entirely independently of other leading computer scientists and mathematicians of his day.


First digital computers

John Vincent Atanasoff and Clifford E. Berry of Iowa State University developed the Atanasoff–Berry Computer (ABC) in 1942. It was described as the first automatic electronic digital computer.

A reconstruction of the Colossus

Colossus was the first electronic digital programmable computer, and was used by the British at Bletchley Park to break German codes during World War II. British engineer Tommy Flowers (1905–98) designed and built the Colossus in 1943. Its operation relied on a large number of vacuum tubes or thermionic valves, early types of electronic components

ENIACBuilt under the direction of John Mauchly and J. Presper Eckert at the University of Pennsylvania in 1946, ENIAC (Electronic Numerical Integrator and Computer) was the first electronic programmable computer built in the US. ENIAC was similar to the Colossus, though much faster and more flexible. Once a program had been written, it needed to be mechanically set into the machine by manually resetting its plugs and switches. The machine weighed 30 tons and contained more than 18,000 vacuum tubes. Many people consider the EINAC to be the first digital computer, because, unlike the ABC or Colossus, it was fully functional.

Replica of the Baby

The “Baby”

The Manchester Small-Scale Experimental Machine (SSEM), nicknamed the “Baby”, was the world's first stored-program computer. It was built at the University of Manchester by Frederic C. Williams, Tom Kilburn and Geoff Tootill, and ran its first program in 1948. It was the first working machine to contain all of the elements essential to a modern electronic computer. Developed from it was the Manchester Mark 1 in 1949, and, two years later, the Ferranti Mark 1, the world's first commercial, general-purpose computer.



A transistor


The transistor was invented in 1947, and soon replaced vacuum tubes in computer designs. Transistors are smaller and require less power than vacuum tubes, so give off less heat. Transistorized computers could contain tens of thousands of circuits in a compact space. A team at the University of Manchester designed and built a machine using transistors instead of valves in 1953, but the first completely transistorized computer was built by the electronics division of the Atomic Energy Research Establishment at Harwell in 1955.


Integrated circuit

Integrated circuits

The next great advance in computing technology came with the invention of the integrated circuit. The first practical ICs were invented by Jack Kilby at Texas Instruments and Robert Noyce at Fairchild Semiconductor in 1958–59. Modern circuits use integrated circuits, or microchips, in which microscopically small components and the connections between them are built into a wafer of semiconductor material, which is normally silicon. This new development led to the invention of the single-chip microprocessor, the Intel 4004, designed by Ted Hoff, Federico Faggin and Stanley Mazor at Intel in 1971.


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The word "computer" was first recorded as being used in 1613 and originally used to describe a person—someone who performed calculations or computations.


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