History of Computers
Computers are devices that are used to carry out tasks that people want done in a more efficient and usually faster way than can be done by the human brain. There are two types of computers, analog and digital. Analog are devices that require human operation like the tide predicting machine made by Sir William Thomson, and digital is like a personal computer, which uses a series of codes and programs to calculate data.
Computing devices have existed for thousands of years, such as a form of tally stick, which was a piece of wood used to keep track of numbers. The first 'analog computer' is known as the Antikythera mechanism, a complex device that used gears from 100 BC that could do many functions like track the planets and stars, as well as plot courses for sea travel. In 1770, a Swiss watchmaker named Pierre Jaquet-Droz would build a mechanical doll that could be 'programmed' by switching a series of digits, and doing so would cause it to write out different letters to make any word.
The first programmable computer was designed by Charles Babbage, who was an English mechanical engineer. He created the design for it in the early 19th century, and would develop the difference engine, which was an automated mechanical calculator. This device would primarily be used for navigational calculations, but he would realize he could use it more generally, and in 1833, designed the first Analytical Engine, which was a device that had all the components of a modern computer. He was far too ahead of his time, and he would never complete one, but his son would complete one in 1888 as well as demonstrate how it used computing tables in 1906.
As the sciences grew in the first half of the 20th century, so too did the need for more sophisticated analog computers. These computers used manual or electric models for computations, but they still could not program nor had the accuracy that modern computers have. The first modern analog computer was a tide predicting machine made by Sir William Thomson in 1872. In 1927, the analog computer would peak with a differential analyzer, solving complex equations with balls and discs.
By 1938 the analog computer would already start to be on its way out. The United States Navy developed the first electromechanical (electric switch that triggered relays to prefer calculation) analog computer small enough to be put on a submarine, known as the Torpedo Data Computer, a computer that helped with the problem of hitting moving targets with torpedoes. All electric computers that used vacuum tubes, which are electric currents between electrodes in a vacuum controlled by a device, would take over quickly. The Z2 was one example of this, made by German engineer Konrad Zuse in 1939.
In 1941, Zuse made the first programmable and fully automatic computers, named the Z3. It used punched film, similar to a CD but you had to manually punch the program into a slip then insert it in a slot in order to program, and could store 64 words in its memory. The Z3 was considered Turing complete, meaning a program can be written and will find an answer to what it was programmed to do.
Throughout World War II, computers were used in mass amounts. Two of the greatest examples of this are Enigma, a German computer that coded all messages for the Nazis, and Colossus, which was developed by Tommy Flowers. Colossus was the first electronic digital programmable computer. These would lead to modern computers, described in Alan Turing's 1936 paper On Computable Numbers.
Alan Turing would describe a device known as a 'Universal Computing Machine'. This machine would be able to execute instructions (programs) from tape, which would program the machine. This led to the invention of transistors, which replaced vacuum tools, in 1947. This led to integrated circuits; invented by Jack Kilby and were 'a body of semiconductor material'. The next step was the microprocessor, created by Ted Hoff Federico Faggin and Stanley Mazor at Intel. This led to the shrinking of computers, eventually the personal computer. Now, computers are everywhere, and almost everyone is always carrying a small computer in their pockets, commonly known as a cell phone.
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