This document discusses the five generations of computers based on the main processing device used: - First generation used vacuum tubes from 1945-1956. They were large in size, unreliable, and produced heat. - Second generation used transistors from 1956-1963. They were smaller with faster speeds but still overheated. - Third generation used integrated circuits from 1964-1971. They were much smaller and cheaper to produce but still complex. - Fourth generation from 1971 onward used integrated circuits with VLSI. They were compact with low power consumption and cheap production. - Fifth generation uses integrated circuits with parallel processing and is focused on artificial intelligence.

3. Computer can classified in to five types according to
generations i.e time period
. First generation computer
. Second generation computer
. Third generation computer
. Fourth generation computer
. Fifth generation computer

4. . First generation computer
Period : 1945 – 1956
Inviter : Lee de Forest
Main processing device : Vacuum tubes

5. Vacuum tube

6. Vacuum tube

7. Vacuum tube

8. Vacuum tube

9. Vacuum tubes

10. Observing Vacuum tube

11. Observing Vacuum tube

12. Vacuum tube tester

13. Punched curds

14. Punched card voting Punched card decks

15. Punched cards models

16. Large punched cards

17. . First generation computer
Advantages :
. It was only electronic device
. First device to hold memory
Disadvantages :
. Too bulky i.e large in size
. Vacuum tubes burn frequently
. They were producing heat
. Maintenance problems

18. Too bulky i.e large in size

19. Vacuum tubes burn frequently

20. Maintenance problems

21. . Second generation computer
Period : 1956 – 1963
Inviter : William Shockley
Main processing device : Transistor
Storage media : Magnetic disc

22. Transistor
1 2

23. Transistor board

24. . Second generation computer
Advantages :
. Size reduced considerably
. The very fast
. Very much reliable
Disadvantages :
. They over heated quickly
. Maintenance problems

25. . Third generation computer
Period : 1964 – 1971
Inviter : Jack Kilby
Robert Noyce
Main processing device : IC (integrated circuit)
Storage media : Floppies

26. IC (integrated circuit)

27. ICs (integrated circuits)

28. IC (integrated circuit)

29. . Third generation computer
Advantages :
. ICs are very small in size
. Improved performance
. Production cost cheap
Disadvantages :
. ICs are sophisticated

30. . Fourth generation computer
Period : 1971– present
Inviter : Ted Hoff
Main processing device : ICs with VLSI
(Very Large Scale Integration)
Storage media : Floppies, CDs.

31. ICs with VLSI
(Very Large Scale Integration)

32. . Fourth generation computer
Advantages :
. It is a compact
. Less power consumption
. Production cost is cheap
Disadvantages :
. No artificial intelligent.

33. . Fifth generation computer
Period : present and beyond
Main processing device : ICs with parallel
processing
Storage media : Video disks
Advantages :
. Artificial intelligence
. Expert system

34. . First generation computer . Second generation computer
. Third generation computer . Fourth generation computer
. Fifth generation computer
Vacuum tubes Transistors
ICs ICs with VLSI
ICs with parallel
processing

35. Computer is a group of electronic devices used to
process the data.
The characteristics of a computer are:
4. Accuracy
5. Automation
6. Functionality
7. Tirelessness
1. Speed
2. Reliability
3. Memory capacity

36. 1. Speed: computer process the data at an
unimaginable speed. The speed of the computer
ranges up to Nano seconds.
2. Reliability: The next important characteristic of a
computer is its reliability. we can always rely on
the information given by a computer.
3. Memory capacity: The memory capacity of a
computer is measured in in bits and bytes. Large
amount of the data can be stored in computer and
retrieved. Memory capacity of the computer
ranges in Giga bytes.

37. 4. Accuracy: Accuracy of the computer is very
high it performs calculation with greater accuracy
in less time.
5. Automation: a computer allows automation
for any process designed in the from of a
program. A program can be executed any
number of times to repeat the process.

38. 6. functionality: computer can performs many kinds
of jobs. They not process the data but also can be
Used for plying music, movies, and printing jobs.
It finds its applications in all most all the fields.
7. Tirelessness: A computer never gate tired.