1. Information Technology
Generations of Computers

2. Generations
A generation refers to the state of improvement in the development of a product.  This term is also used in the different advancements of computer technology.  With each new generation, the circuitry has gotten smaller and more advanced than the previous generation before it. 

3. Generations
As a result of the miniaturization, speed, power, and memory of computers has proportionally increased.  New discoveries are constantly being developed that affect the way we live, work and play

4. First Generation 1945-1956 - The Vacuum Tube Years
The first generation computers were huge, slow, expensive, and often undependable
In 1946 Americans, Presper Eckert, and John Mauchly built the ENIAC electronic computer which used vacuum tubes instead of the mechanical switches of the Mark I.

5. First Generation
The vacuum tube was an extremely important step in the advancement of computers.  It's purpose was to act like an amplifier and a switch. 
Without any moving parts, vacuum tubes could take very weak signals and make the signal stronger (amplify it).  Vacuum tubes could also stop and start the flow of electricity instantly (switch). 

6. Vacuum Tube

7. Second Generation 1956-1963 The Era of the Transistor
In 1947 three scientists, John Bardeen, William Shockley, and Walter Brattain working at AT&T's Bell Labs invented what would replace the vacuum tube forever. 
This invention was the transistor which functions like a vacuum tube in that it can be used to relay and switch electronic signals.

8. Second Generation
The transistor was faster, more reliable, smaller, and much cheaper to build than a vacuum tube. 
One transistor replaced the equivalent of 40 vacuum tubes.
They were very cheap to produce

9. Second Generation
Transistors were found to conduct electricity faster and better than vacuum tubes. 
They were also much smaller and gave off virtually no heat compared to vacuum tubes. 
Their use marked a new beginning for the computer. 

10. Transistors

11. Third Generation
Integrated Circuits -Miniaturizing the Computer
The integrated circuit, or as it is sometimes referred to as semiconductor chip, packs a huge number of transistors onto a single wafer of silicon. Placing such large numbers of transistors on a single chip vastly increased the power of a single computer and lowered its cost considerably

12. Third Generation
Robert Noyce of Fairchild Corporation and Jack Kilby of Texas Instruments independently discovered the amazing attributes of integrated circuits
Another 3rd Generation development was the use of ‘high level’ language
This comprised of English words and base 10 number system. E.g. 101, 1110

13. Integrated Circuit (IC)

14. Fourth Generation 1971-Today - The Microprocessor
The microprocessor is described as a single chip that could do all the processing of a full-scale computer
Initially there was the LSI – large-scale integration, where hundreds of components were placed on the chip

15. Fourth Generation
In the 1980s there was the (Ultra Large Scale Integration)ULSI – where thousands then millions of components were placed on the chip
This led to the invention of personal computers, or microcomputers.
Computers were now smaller, cheaper and much faster and reliable

16. The Microprocessor

17. Fifth Generation
Fifth generations computers are only in the minds of advance research scientists and being tested out in the laboratories

18. Fifth Generation
These describe computers of the present time and those still to come
Computers would be able to mimic human behaviour
They will contain ‘artificial intelligence’
They will be able to accept spoken instructions

19. Fifth Generation
Parallel processing will be introduced – they would be capable of performing multiple, simultaneous operations
They will contain multiple processors
They will be very powerful and reliable
They will be capable of ‘learning’

20. Home Assignment
Identify the main components of the FIVE generations of computers and show how these components have affected the following:
Speed
Size
Reliability
Cost