GENERATION OF COMPUTERS

The term generation indicates the type of technology used in the computer construction. As new

technology was emerging, it was being used in the making of computer. The new technology

improved the speed, accuracy and storage capacity of the computers. Different technologies have

been used for computers in different times.

Therefore, computers can be divided into five generations depending upon the technologies used.

These are:

First Generation (1942 - 1955)

Second Generation (1955 - 1964)

Third Generation (1964 - 1975)

Fourth Generation (Since 1975)

Fifth Generation (Since 1980)

1. First Generation Computers (1942 - 1955)

The vacuum tube technology was used in first-generation computers. Mark-1m, ENIAC,

EDSAC, EDVAC, UNIVAC-1 etc. machines belong to the first generation of computers. The

machine language only was used in first-generation computers.

Advantages

The main advantages of first-generation computers were:

These computers were the fastest of their time.

They were programmed using machine language.

The electronic digital computers were introduced due to the vacuum tube technology.

Disadvantages

The main disadvantages of first-generation computers were:

Very big in size

Not reliable

Consumed large amount of energy

Constant maintenance required

More heat generated and air-conditioning was required

More costly

Very slow in speed (data processing)

It was difficult to programmed, because they used only machine language

Non-portable

Limited commercial use

2. Second Generation Computers (1955 - 1964)

The transistor technology was used in second-generation computers. The electronic component

transistor was invented in 1948 at Bell Laboratories. The transistor is smaller in size and more

reliable than vacuum tube. Therefore, the transistor technology was used in computer in place of

vacuum tube technology. The programming assembly language was also introduced in second-

generation of computers.

Advantages

The main advantages of second-generation computers as compared to first-generation computers

are:

Low in cost

Smaller in size

Fast in speed

Less heat generated More reliable and accurate in calculations

Consume low power etc.

Used for commercial purposes

Portable

Assembly language was introduced. This language is easy to write program than machine

language

Disadvantages

The main disadvantages of this generation computers were:

Air-conditioning required

Commercial production was difficult and these were very costly

Constant (or frequent) maintenance required

Only used for special purposes

3. Third Generation Computers (1964 - 1975)

The IC (Integrated Circuits) technology was used in third-generation computers. In a small IC

chip (5 mm square size) a circuit is designed having large number of electronic components like

transistors, capacitors, diodes, resistors etc. Initially, an IC contained only about ten to twenty

components. Thus the IC technology was named as Small Scale Integration (SSI). The third-

generation was based on IC technology and the computers were designed using this technology.

Advantages

The main advantages of third-generation as compared to previous generations of computers

were:

Smaller in size

Production cost was low

Very fast in computational power

More reliable

Low power consumption

Maintenance cost was low because failure rate of harware was very low

Magnetic disk, used for externale storage

More storage capacity

Easily portable

Easy to operate

Upgraded easily

Widely used for various commercial applications all over the world

Lower heat generated

High-level languages were commonly used

Many input/ouput devices were introduced such as mouse and keyboard etc.

Disadvantages

The main disadvantages of thir-generation computers were:

Air-conditioning required

Highly sophisticated technology required for the manufacturer chips

4. Fourth Generation Computers (1975 onwards)

The microchip technology was introduced in this generation of computers. With the

advancement in IC technology, LSI (Large Scale Integration) chips were developed. It was

possible to itegrate over 30,000 or more components on to single LSI chip. After LSI, the VLSI

(Very Large Scale Integration) was developed and the development of microprocessor possible.

It is expected that more than one million components will be integrated on a single chip of VLSI.

Using VLSI technology, the entire CPU is designed on a single silicon chip. The use of

microprocessor as CPU introduced another class of computers called the microcomputers. Thus

fourth-generation may be called Microcomputer generation. IBM introduced its personal

computer for use in 1981.

Advantages

The advantages of fourth-generation as compared to previous generation computers are:

Smaller in size

Production cost is very low

Very reliable

Harware failure is negligible

Easlity portable because of their small size

Totally general purpose

Air conditioning is not compulsory

Very high processing speed

Very large internal and external storage capcity

Used advanced input & ouput devices such as optical readers, laser printers, CD-

ROM/DVD-ROM drives etc.

Disadvantages

The main disadvantages of fourth-generation computers are:

Highly sophisticated technology required for the manufacturer of microprocessor chips

5. Fifth Generation Computers (In process)

The main drawback of first to fourth generation computers is that the computers have not their

own thinking power. These are totally depending upon the instructions given by the users.

Fifth generation computers are supposed to be the ideal computers, but do not exist. The

scientists are working to design such computers that will have the following features.

Having their own thinking power

Making decisions themselves

Having capabilities of learning

Having capabilities of reasoning

Having large capacity of internal storage

Having extra high processing speed

Having capabilities of parallel processing

In these computers following technologies will be used:

ULSIC (Ultra Large Scale Integrated Circuits) technology

Artificial Intelligence (AI) technology also called the kowledge Processor. The AI means

automatic programs that let the machines to think and decide themselves. The programming

languages LISP (List Processor) and PROLOG (Programming with Logic) are used for artificial

intelligence. The scientists at ICOT in Japan use the PROLOG to developt the Artificial

Intelligence software.