Computer Essentials:

Computer Generations

 

“Generation” in computer talk is a step in technology. It provides a framework for the growth of the computer industry. Originally, the term ‘generation’ was used to distinguish between varying hardware technologies. But nowadays, it has been extended to include both the hardware and the software which together make up an entire computer system.

The custom of referring to the computer era in terms of generations came into wide use only after 1964. There are totally five computer generations known till today. Each generation has been discussed below in detail along with their advantages and disadvantages. Although there is a certain amount of overlapping between the generations, the approximate dates shown against each are normally accepted.

 

FIRST GENERATION (1942-1955)

We have already discussed about some of the early computers – ENIAC, EDVAC, EDSAC, etc. These machines and other of their time were made possible by the invention of “vacuum tube: which was fragile glass device that could control and amplify electronic signals. These vacuum tube computers are referred to as first- generation computers.

Advantage

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 device of their time. They could perform computations in milliseconds.

Disadvantages

1. Too bulky in size
2. Unreliable
3. Thousands of vacuum tubes that were used emitted large amount of heat and burnt out frequently
4. Air conditioning required
5. Prone to frequent hardware failures
6. Constant maintenance required
7. Nonportable
8. Manual assembly of individual components into functioning unit required
9. Commercial production was difficult and costly
10. Limited commercial use

SECOND GENERATION (1955-1964)

The transistor, a smaller and more reliable successor to the vacuum tube, was invented in 1947. However, computers that used transistors were not produced in quantity until over a decade later. The second generation emerged with transistors being the brain of computer.

With both the first and the second-generation computers, the basic component was a discrete or separate entity. The many thousands of individual components had to be assembly by hand into functioning circuits. The manual assembly of individual components and the cost of labour involved at this assembly stage made the commercial production of these computers difficult and costly.

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 unit was required
4. Commercial production was difficult and costly

THIRD GENERATION (1964-1975)

Advances in electronic 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”. This 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. Even lower heat generated than second generation computers.
4. These computers were able to reduce computational times from microseconds to nanoseconds.
5. Maintenance cost is low because hardware failures are rare.
6. Easily portable.
7. Totally general purpose. Widely used for various commercial applications all over the world.
8. Less power requirement than previous generation computers.
9. Manual assembly of individual components into a functioning unit not required. So human labour and cost involved at assembly stage reduced drastically.
10. Commercial production was easier and cheaper.

Disadvantages

1. Air-conditioning required in many cases.
2. Highly sophisticated technology required for the manufacture of IC chips.

FOURTH GENERATION (1975 ONWARS)

Initially, the integrated circuits contained only about ten to twenty components. This technology was named small scale integrated (SSI). Later, with the advancement in technology for manufacturing ICs, it became possible to integrate upto a hundred components on a single chip. This technology came to be known as medium scale integration (MSI). Then came the era of large-scale integration (LSI) when it was possible to integrate over 30,000 components onto a single chip. Effort is still on for further miniaturization, and it is expected that more than one million components will be integrated on a single chip known as very large-scale integration (VLSI).

A fourth-generation computer, which is what we have now, has LSI chip as its brain. It is LSI technology which has led to the development of very small but extremely powerful computers. It was the start of a social revolution. A whole computer circuit was soon available on a single chip, the size of a postage stamp. Overnight computers became incredibly compact. They became inexpensive to make and suddenly it became possible for anyone and everyone to own a computer.

Advantages

1. Smallest in size because of high component density
2. Very reliable
3. Heat generated is negligible
4. No air conditioning required in most cases
5. Much faster in computation than previous generations
6. Hardware failure is negligible and hence minimal maintenance is required
7. Easily portable because of their small size
8. Totally general purpose
9. Minimal labour and cost involved at assembly stage
10. Cheapest among all generations

Disadvantage

1. Highly sophisticated technology required for the manufacture of LSI chips.

 

FIFTH GENERATION (YET TO COME)

Scientists are now at work on the fifth-generation computers – a promise, but not yet a reality. They aim to bring us machines with genuine I.Q., the ability to reason logically, and with real knowledge of the world. Thus, unlike the last four generations which naturally followed its predecessor, the fifth generation will be totally different, totally novel, totally new.

In structure it will be parallel (the present ones are serial) and will be able to do multiple tasks simultaneously. In functions, it will not be algorithmic (step by step, with one step at a time). In nature, it will not do just data processing (number crunching) but knowledge processing. In inference, it will not be merely deductive, but also inductive. In application, it will behave like an expert. In programming, it will interact with humans in ordinary language (unlike BASIC, COBOL, FORTAN, etc. which present computers need). And in architecture, it will have KIPS (Knowledge Information Processing System) rather than the present DIPS/LIPS (Data/Logic Information Processing System).

The odds of coming out with a fifth-generation computer are heaviest for Japan. They are already started work in this direction few years back. Japan has chosen the PROLOG (Programming in Logic) language as its operating software and plans to have the final machine talk with human beings, see and deliver pictures and hear the normal, natural language.

Ques 1. What is computer? Why is it also known as a data processor?

Ques 2. List out and explain some of the important characteristics of a computer.

Ques 3. What is an abacus?

Ques 4. Who is known as the father of modern digital computers and why?

Ques 5. Why are modern digital computers often referred to as stored program digital computers?

Ques 6. Give the full form of the following abbreviations used in computer terminology:

IBM, ENIAC, EDVAC, EDSAC, UNIVAC.

Ques 7. What is meant by ‘generation’ in computer terminology? How many computer generations are there till now?

Ques 8. List out the various computer generations along with their basic characteristics.

Ques 9. Write a short note on fifth generation computers.

Ques 10. What are the advantages of transistors over vacuum tubes?

Ques 11. What is an IC? How does it help in reducing the size of computers?

Ques 12. List out some of the advantages of IC technology over transistor technology.

Ques 13. Give the full form of the following abbreviations used in computer terminology:

IC, SSI, MSI, LSI, VLSI, DIPS, LIPS, PROLOG.