Third Generation

THIRD GENERATION COMPUTERS

A computer built with small-scale integration integrated circuits, designed after the mid-1960s. 

Third generation computers use semiconductor memories in addition to, and later instead of,ferrite core memory. The two main types of semiconductor memory are Read-Only Memory (ROM) and read-and-writememories called random-access memory (RAM). 

During the period of 1964 to 1971 Third generation computers were developed. The third generation computers emerged with the development of IC (Integrated Circuits). The invention of the IC was the greatest achievement done in the period of third generation of computers. IC was invented by Robert Noyce and Jack Kilby in 1958-59. IC is a single component containing a number of transistors. Transistors were miniaturized and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers.

Third generation computers use semiconductor memories in addition to, and later instead of,ferrite core memory. The two main types of semiconductor memory are Read-Only Memory (ROM) and read-and-writememories called random-access memory (RAM). 

Keyboards and monitors developed during the period of third generation of computers. The third generation computers interfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory.

A technique called microprogramming became widespread and simplified the design of the CPUs andincreased their flexibility. This also made possible the development of operating systems as software ratherthan as hard-wiring. 

A variety of techniques for improving processing efficiency were invented, such as pipelining (parallel operation of functional units processing a single instruction), and multiprocessing (concurrent execution of multiple programs). 

CHARACTERISTICS
1) IC was used instead of transistors in the third generation computers.
2) Third generation computers were smaller in size and cheaper as compare to the second generation computers.
3) They were fast and more reliable.
4) High level language was developed.
5) Magnetic core and solid states as main storage.
6) They were able to reduce computational time and had low maintenance cost.
7) Input/Output devices became more sophisticated.

Advantages

1. Smaller in size as compared to previous generation computers.
2. Even more reliable than second-generation computers.
3. Even lower heat generated than second generation computers.
4. These computers were able to reduce computational times from microseconds to nanoseconds.
5. Maintenance cost is low because hardware failures are rare.
6. Easily portable.
7. Totally general purpose. Widely used for various commercial applications all over the world.
8. Less power requirement than previous generation computers.
9. Manual assembly of individual components into a functioning unit not required. So human labour and cost involved at assembly stage reduced drastically.
10. Commercial production was easier and cheaper.

Disadvantages

1. Air-conditioning required in many cases.
2. Highly sophisticated technology required for the manufacture of IC chips.

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