History of Computer (1942-2007)

Q 3: Write a note on computer generations.

The Computer Generations:

In terms of the computer “Generation” is a step in technology. It provides a structure for the growth of the computer industry. At first, the term ‘generation’ was used to distinguish between changeable hardware technologies. Following are the different generations of a computer.

FIRST GENERATION (1942-1955)

First generation computers were made possible by the invention of “Vacuum tube”, which was a fragile glass device that could control and amplify electronic signals. Vacuum tube computers are referred to as first generation computers.

Examples: ENIAC, EDVAC, EDSAC, etc belong to first generation computers.

Advantages:

1. Vacuum tubes were the only electronic components available during those days.

2. Vacuum tube technology made possible the advent of electronic digital computers.

3. These computers were the fastest calculating devices of their time.

They could perform computations in milliseconds.

Disadvantages:

1. Too bulky (large) in size

2. Unreliable

3. Thousands of vacuum tubes that were used produced large amount of heat and burnt out frequently.

4. Air conditioning required
5. Prone to frequent hardware failures 6. Constant maintenance required

7. No portable

8. Commercial production was difficult and costly

9. Limited commercial use

SECOND GENERATION (1955-1964)

The Vacuum technology was replaced with Transistor (a smaller and more reliable). Transistors were invented in 1947. In second-generation computers, transistors were used as the brain of the computer.

Advantages:

1. Smaller in size as compared to first generation computers.

2. More reliable

3. Less heat generated

4. These computers were able to reduce computational times from milliseconds to microseconds. 5. Less prone to hardware failures

6. Better portability

7. Wider commercial use

Disadvantages:

1. Air-conditioning required

2. Frequent maintenance required

3. Manual assembly of individual components into a functioning was required

4. Commercial production was difficult and costly

THIRD GENERATION (1964-1975)

Advances in electronics technology continued and the advent of “microelectronics” technology made it possible to integrate large number of circuit elements into very small (less than 5 mm square) surface of silicon known as “Chips”. The new technology was called “integrated circuits” (ICs). The third generation was based on IC technology and the computers that were designed with the use of integrated circuits were called third generation computers. Advantages:

1. Smaller in size as compared to previous generation computers

2. Even more reliable than second generation computers

3. Working Speed of these computers was faster as compared to previous generations

4. Maintenance cost was low

5. Easily moveable

6. Totally general purpose and widely used for various commercial applications all over the world

7. Less power requirement than previous generation computers

8. Commercial production was easier and cheaper

Disadvantages:

1. Air-conditioning required in many cases

2. Highly difficult technology required for the manufacture of IC chips

FOURTH GENERATION (1975 ONWARD)

In this generation a revolution came in the field of computer due to the invention of microprocessor. In this generation ICs were replaced with microprocessor. A microprocessor is a small chip which contains thousands ICs onto a single chip. Invention of microprocessor reduced the size of the computer.

Advantages:

1. Smallest in size because of high components density

2. Very reliable

3. Heat generated is small

4. No air conditioning required in most cases

5. Much faster in computation than previous generations

6. Hardware failure is minor

7. Easily portable because of their small size

8. Totally general purpose

9. Big memory

10. Cheapest among all generations

Disadvantages:

1. Highly difficult technology is required for the manufacturing of microprocessor Chip

FIFTH GENERATION (YET TO COME)

Scientists are now at work on the fifth generation computer – promise, but not yet a reality. They aim to bring us machines with genuine