CPU

Computer

A computer is an electronic device that can receive a set of instruction or programme,and then carry out this programme by performing calculate on numerical data or by manipulating other forms of information.
What is Computer?
Computer derives its name from the word Compute that means calculation. It can be said that Computer is a device used for calculation. Nowadays Computer is not only limited to computation, but also used for making phone calls, maintaining databases, listening songs, viewing movies etc, so a more formal definition of Computer is required. Computer is an electronic device that processes or transforms data into useful information by executing a series of predefined instructions.
Input---->Processing Unit-->Memory<-- ---->Out Put---->

Generations of Computer

Generation	Period	Main Electronic components	Main computer	Operating system
I	1945-56	Vacuum Tubes,Flip-Flops	UNIVAC,ENIAC	Mainly Batch Operating system
II	1956-63	Translators	IBM-700,IBM-1401	Time sharing Operating system
III	1964-71	Integrated Circuits(ICS)	IBM-1620,ATLAS,ICL-1901,IBM-360,IBM-370	Real Time and Time sharing Operating system
IV	1971-Present	Micro processors(LSI-Large scale Integration)	NCR-395,CDC-1700,Apple,DCM	Time Sharing Networks
V	Present and Beyond	Optical fibre,artificial Intelligence(VLSI and VVLSI-Very Very Large Scale Integration)	-----------	------------

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