Five 5 Computer Generations

1.First Generation (1951-1958) - The Vacuum Tube.
     In this generation of  computer vacuum tubes were used. because of computer was big in size  for example that times computer ENJAC weighted 30 ton and it occupied 80*50 square feet place it was so expensive that an ordinary person could no buy it and for its use many persons were needed and the speeds of these computers were very slow.
                

                                     Characteristic;                                 a)  Comparatively large in size as compared to present day computers                                          b) Generated lot of heat, they were not consistent andreliable as the values lended to fail frequntly.  c) low capacity internal storage.    d) Individual non- related models.  e) processor operated in the milliseconds speed rang.                  f) Internal storage consiste of magnetec drum and delays lines     2.Second Generation (1959-1964)                 the transistors;                   In this generation instead of tube vacuum tubes transistor were used. one transistor can perform work of two vacuum tubes and they are 50 times smaller than the tubes these transistors also use less electric power then the tubes so less heat produced.

CHARACTERISTICS;

a) smaller in size compared to the first generation computers.

b) Generated a lower level of heat, as components were much smaller.

c) Greater degree of reliability because of solid state technology.

d) Higher capacity of internal storage.

e) Use of core storage instead of magnetic durm and delay lines.

f) Related series of processors- the family concept.

g) processor operated in the microsecond speed.

h) High cost direct accesses storage.

3.Third generation (1965-1970)- The integrated Circuit;

In this generation transistor replaceed by IC"s  integrated Circuits ordinary IC is more or less one inch long and they work equal to 800-1000 transistors. this is the reason that these computers were thousand times faster pervious generations computers.

 characteristics;

a) smaller in size compared to the second generation computers.

b) High capacity internal storage.

c) Remote communication facilities.

d) Multiprogramming facilities.

e) Reduced cost of direct access storage.

f) Pprocessors, which operate in nanosecond speed rang.

g) Ranges of computers with a common architecture whereby models were pward compatible.

h) Use of high level language such as COBOL.

i) Wide range optional peripherals.

4.Fourth Generation (1971-1990) - The Microprocessor.

After 1970 large scal integrated technology was  introduced. in this generation instead of IC, LSI chip which was called Microprocessor chip were used computer related to this generation are of very high speed in its making expenses are less due to which they were made in large number

Characteristics:

a) Increase input/output capacity longer component life as well as greater system reliability.
b) powerful language were developed to broaden the use of multiprogramming and multiprocessing.
c) batch processing to online remote interactive processing.
d) develoment of microprocessor chip which contain an entire central processing unit on a single silicon chip.
e) The fourth generation computers called microcomputer.
f) large integrated circuits has made the fourth generation (micro) computers very compact much less expensive faster more reliable and of much greater data processing.

5.Fifth Generation (1991-onwards)
In this generation parallel processor and ULS(Ultra Large Scale Integration) Technology was introduced. with the help of these computers complicated theorem of science can be solved. They are also being used in nuclear and space technology.

Characteristics;

1. The artificial intelligence.
2. Automatic programming.
3. Connectivity.
4. Controle of Robots.
5. Computer made easy and natural to use.
6. problem solving systems.

the end