1. Presentation By Jaspreet Rekhi Introducing Sites: - www.rhombnet.com

2. Evolution of Computers and Computer Generations

3. ABACUS
4th Century B.C.
The abacus, a simple counting aid, invented in Babylonia (now Iraq) in the fourth century B.C.
This device allows users to make computations using a system of sliding beads arranged on a rack.

4. BLAISE PASCAL
In 1642, the French mathematician and philosopher Blaise Pascal invented a calculating device that would come to be called the "Adding Machine".

5. Pascal's mechanical Adding Machine automated the process of calculation. Although slow by modern standards, this machine did provide a fair degree of accuracy and speed.
Barren Gotterfried Wilhelm invented the first machine for multiplication

6. Charles Babbage
Invented Difference Engine for producing reliable tables to support mathematical and statistical data
Then he produced a new idea of an Analytical Engine for faster processing of arithmetic operations
Analytical Engine was capable of performing 60 additions per minute
But he was unable to produce working model of this engine

7. Some Well Known Early Computers
The Mark I Computer ( )
Designed by Howard A. Aiken, Professor of Harvard University in collaboration with IBM Corporation
Automatic Sequence Controlled calculator
First fully automatic machine
Electromechanical device (both electrical & mechanical)
Complex in design and huge in size
Used over 3000 electrical switches, approximately 50 feet long and 8 feet high
Performed 5 basic arithmetic operations: addition, subtraction, multiplication, division and table reference

8. The Atanasoff-Berry Computer (1939-42)
Designed by Dr. John Atanasoff and his assistant Clifford Berry
An electronic machine to solve mathematical equations
Used 45 vacuum tubes for internal logic and capacitors for storage
The ENIAC ( )
Electronic Numerical Integrator and Calculator
Designed by a team of people at Moore School of Engineering, U.S.A
Team led by Professors J. Presper Eckert & John Mauchly
First electronic computer
Developed because of military needs to solve ballistic related problems
Used vacuum tubes
Could add and multiply two numbers in 200 and 2000 microsec respectively
Programs were wired on board and hence couldn’t be changed

9. The EDVAC ( )
Electronic Discrete Variable Automatic Computer
Designed by Von Neumann
Used concept of stored program in the computer memory so that they can be changed as and when required
Von Neumann also introduced concept of storing both instructions in binary form
EDSAC ( )
Electronic Delay Storage Automatic Calculator
Designed by group of scientists lead by Professor Maurice Wilkes
Designed at Cambridge University Mathematical Laboratory
Executed its first program in May 1949
Addition & multiplication took 1500 & 4000 microseconds respectively

10. The UNIVAC I (1951) Universal Automatic Computer
First Digital Computer
First UNIVAC machine was installed in Census Bureau and was continuously used for 10 years
First business use in 1954 by General Electric Corporation

11. Computer Generations First Generation (1942-1955)
Second Generation ( )
Third Generation ( )
Fourth Generation ( )
Fifth Generation (1989-Present)

12. First Generation Used thousand of vacuum tubes
They were fastest calculating devices.
Too large in size
Data & instructions were fed with the help of punched cards
Instructions were written in machine or assembly level language
Large amount of heat due to thousands of vacuum tubes, so air conditioning was required
High power consumption

13. Frequent hardware failure due to burn out of tubes
Costly to manufacture and maintain these computers
The first computer prototype using vacuum tubes was ENIAC

14. Second Generation Use of transistors instead of vacuum tubes
Invented by John Bardeen, William Shockley and Walter Brattain
Invented at Bell Laboratories, USA in 1947
Easier to use and handle
No burning out, but hardware failures were still there
Almost ten times faster than tubes
Consumed almost one-tenth the power consumed by tubes

15. Much smaller in size
Less expensive to produce but still costlier
Produce less heat as compared to tubes but air conditioning was required
Magnetic disk and magnetic tapes were used as memory
High level programming languages such as FORTRAN, COBOL were used
Easier to program these computers
Batch operating system was used

16. Third Generation
In 1958, Jack St. Clair Cilby & Robert Noyce invented integrated circuits
IC’s consist of several electric components like transistors, resistors and capacitors embedded on a single chip of silicon
SSI, MSI technology
More powerful & faster than second generation computers (could perform 1million instructions/sec)
Smaller in size and hence require small space for installation
Require less power and produce less heat but still need proper air conditioning

17. More reliable and very less prone to hardware failure
Faster and large memory as compared to second generation computers
Were less costlier and easy to manufacture and maintain
Time sharing operating system allowed use of single computer by multiple users

18. Fourth Generation Use of IC’s with VLSI technology
Microprocessors and semiconductor memory
Larger memory because of larger hard disks and floppy disks and magnetic tapes as portable storage media
Very less heat hence no air conditioning was required instead fans were used
Graphical User Interface operating systems were used
Very easy to manufacture & maintain them and cost very less
Very fast as compared to computers in early generations

19. Fifth Generation IC’s based on ULSI technology
Portable PC’s (notebook computers) were much smaller and handy than fourth generation computers
Much faster and powerful than computers in earlier generations
Consume very less power
Hot plug technology
Less costlier and easy to manufacture and maintain
Newer and more powerful applications make computers more easy to use in every field

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By : - Jaspreet Rekhi