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.

First Generation (1942-1955)

First generation machines were invented with the invention of vacuum tubes. A vacuum tube was a fragile glass device that could control and amplify electronic signals. These vacuum tube computers are referred to as first generation computers.

Advantages

1. Vacuum tubes were the only electronic components available 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 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 constant hardware failure.
6. Constant maintenance required.
7. Non-portable.
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 the 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 assembled by hand into function circuits. The manual assembly of individual components and the cost of labor 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 electronics technology continued and the advent of "microelectronics" technology made it possible to integrate large number of circuit elements into very small (less than 5mm square) surface of silicon known as "chips". This new technology was called "integrated chips" (ICs). The third generation was based on IC technology and the computer that was designed with the use of integrated circuits was 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 failure is rare. 
6. Easily portable.
7. Totally general purpose.
8. Less power requirement than previous generation computers, 
9. Manual assembly of individual components into a functioning unit was not required. 
10. Commercial production was cheaper and easier. 

Disadvantages

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

Fourth Generation (1975 onwards) - 89

Initially, the integrated circuits contained only about ten to twenty components. This technology was named small-scale integration (SSI). Later, with the advancement in technology for manufacturing ICs, it became possible to integrate upped a hundred components on a single chip. This technology came to be known as medium scale integration (MSI). Then came the era of (LSI) large-scale integration when it was possible to integrate over 30,000 components onto a single chip. Efforts 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 (VLSI) very large scale integration.)

A fourth generation computer, which is what we have now, has LSI chips 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 labor 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 to bring a machine with genuine I.Q., the ability to reason logically, and with real knowledge of the world.

The main features are:

1. In structure it will be parallel and will be able do multiple tasks.
2. In nature it will be knowledge information processing system (KIPS) and not data processing (DIPS).
3. In application it will be an expert.