Wednesday, 2 December 2015

Study Notes Computers Generations

The development of computer technology is generally divided into the following phases :

First Generation (1942 - 1956) - Vacuum Tubes

Vacuum tubes is the only electronic components available during those days.

These computers were the fastest calculating devices of that time. They could perform calculations in Milli-Seconds but there were many disadvantages in them. They were too big in size, Not portable, Air-Conditioning was required for their commercial use and production was also difficult. The UNIVAC (Universal Atomic Computer) and ENIAC (Electronic Numerical Integrator and Computer) are the examples of First Generation Computers. 
  • UNIVAC was the first Commercial Computer
     to a business client the U.S. Census Bureau in 1951
     (till then, all computers were for research purpose).
  • ENIAC was the world's first Operational Electronic Digital Computer. 

Second Generation (1956-1963) - Transistors

The Transistor, a smaller and more reliable source than the vacuum tube was invented in 1947 at Bell Labs.  This Transistor is a device made by semiconductor material that amplifies the signal or opens or closes a circuit. However computer that used transistors was not produced in quantity. The second generation emerged with transistors being the brain of Computer. It was smaller in size as compared to first generation computers and more reliable. The disadvantages of it were the requirement of air-conditional room, frequent maintenance that it required, commercial production. 

Third Generation (1964-1971) - Integrated Circuits (ICs)

A new technology called Integrated Circuit was invented in 1963. This technology made a big change in Computer world. The third Generation computers were developed by using this IC technology. In this technology Transistors were miniaturized and placed on Silicon Chips. These Silicon Chips are also called as Semiconductors. These Semiconductors helped to increase the speed and efficiency of Computers. 

Fourth Generation (1971 - Present) - Microprocessors

Microprocessors brought the Fourth Generation computers. The Microprocessor is a Single Silicon Chip which contains some thousands of Integrated Circuits. Simply we can say that it is the heart of Personal Computers. Personal computers were started in Third Generation. With the invention of Microprocessors, They've got a new life. The Microprocessor controls the logic of almost all devices from small clocks to big automobiles. 
There are 3 basic characteristics for Microprocessors. They are.....
  1. Instruction Set : The set of Instructions Given to it and it can execute.
  2. Bandwidth : The number of bits it can process in a single Instruction.
  3. Clock Speed : The number of Instructions per second the processor can execute. These can be measured in MHz (Megahertz)

Fifth Generation (Present - Future) - Artificial Intelligence

The fifth Generation Computers are based on Artificial Intelligence. Simply Machine Brains. These systems works with the help of Neural Networks. The target of this is to make computers which can think like human. Currently there is no computer in the world which can exhibit full artificial intelligence (i mean, to simulate COMPLETE human behavior). Scientists are still working on these type of systems. So, we put them in Fifth Generation.

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