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FROM THE HISTORY OF COMPUTER
The modern computer is based on the ideas and inventions of many scientist and engineers of the past. Actually, the computer has had three birth dates. One as a mechanical computing device (about 550 B.C.), another as a concept (1883), and the third as a modern electronic digital computer (1946).
The first mechanical calculator, called the abacus, was invented in Babylonia around 500 B.C. The abacus provided the fastest method of calculating and was used until 1642, when the French scientist Blaise Pascal invented a calculator made of wheels and cogs.
It was in 1833 that the concept of the modern computer appeared in Britain. The British mathematician Charles Babbage designed an "analytical engine" that contained all the necessary elements of a modern computer: input devices, memory, a computing unit, a control unit, and output devices. The steam-driven "analytical engine" was as large as a locomotive.
In the late 1920s and 1930s, several new types of calculators were constructed and put into operation. But it was only in 1939 that the real prototype of a computer based on a binary numbering system was produced.
It was reasoned that binary numbers were better suited to computing than were decimal numbers, because the two digits — 1 and 0 — could easily be represented by electrical circuits, which were either on or off.
And the modern electronic digital computer appeared in 1946.
The development and use of computers in the modern world has led to a revolution in the way people all over the world communicate with each other and transfer information.
The lst-generation computer systems (beginning approximately in 1950) employed vacuum tubes as the primary switching component in the processor. Memories were constructed of liquid mercury delay lines or magnetic drums.
The 2nd-generation systems began around the late 1950s and used transistors in place of vacuum tubes and memories were made of magnetizable cores (M-220, IBM-1401 are examples). Size was reduced and reliability was improved significantly in the 2nd-generation systems. The 2nd generation was primarily a batch processing environment with a single program running at one time.
The 3rd-gene ration computers, beginning in the mid-1960s, introduced processors made of integrated circuits (SM-3, IBM-360 and 370 are examples). The 3rd generation also introduced system software technologies like Operating Systems and Data Base Management Systems. On-line systems were widely developed throughout the 3rd generation, although most processing was still batch oriented.
The 4th generation is more evolutionary than revolutionary. Starting in the mid-1970s, the 4th-generation computer logic and memory were built almost entirely of chips which contain extremely large numbers of electronic components. The 4th generation embraces extensive integration of small and large computers together in a distributed processing environment.
The 5th generation had become formalized by 1990s. Optical fibers, video-discs and other technologies were used to construct the 5th-generation computer systems. Artificial intelligence techniques were incorporated into every type of application. Modern machines are able to come into contact with a person rather intelligently. (2 730)