Monday, 22 April 2013

Computer Generations

First Generation(1942-1955)

This Generation is considered to be form 1942-1955. These Machines were designed with the help of vacuum tubes. The main features of this Generation Computer were:
1. Were designed with vacuum tube’s which was only electronic component available during those days.
2. These computers were fastest of their time and could perform calculations in milliseconds.
3. They were bulk in size due to the use of thousands of vacuum tubs.
4. These devices were non-potable and were more frequent to failure.

Second Generation(1955-1964)

 This Generation is considered from 1955 to 1964. This Generation was based upon transistor Technology. The first transistor invented at AT&T tall Laboratories 1947. The main feature of this Generation Computer were:
1. Used Transistor inspite of vacuum tubes.

2. Small in size as compared to 1st Generation Computers.
3. They were more reliable and heat Generation was low.
4. Calculation time in Microseconds.
5. Were less prone to Hardware failure.
6. Were required AC and frequent maintenance.

Third Generation(1964-1975)

Invention of microelectronics made possible to Integrate large no of circuit elements into small silicon surfaces, called "chips". This new Technology was called Integrated Circuits(ICS). This Generation was based of ICS and is considered to be from 1964 to 1975. Main features of this Generation Computer were:
1. They were small in size as compared to previous Generation PCs.
2. They were more reliable.
3. Less heat Generation.
4. Computational time in nano seconds.
5. Easily portable.
6. Were designed for General purpose use.
7. Power requirement was less.
8. Commercial Production was easy and cheap.

Fourth Generation(1975 onwards)

The initial stage of ICs was SSI (Small Scale Integration) and later with the advancement in the Technology it became possible to integrate hundreds of components per chip and Medium Scale Integration (MSI) came into existence after that LSI(Large Scale Integration ), VLSI (Very Large Scale Integration) came into existence. Fourth Generation was based on LSI integration and is considered to be from 1975 onwards.Main feature of this Generation are:
1. Smallest in size due to LSI.
2. Very much reliable.
3. Power consumption very low.
4.Negligible  heat Generation.
5. fastest among all previously Generations.
6. Minimal hardware failure.
7. Easily portable.
8. Minimal labor and cost involved in assembly.
9. Cheapest among all Generation.
10. Available for General use in large scale.

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