Generations of Computer

GENERATIONS 

Computer being an electronic device, its size, capabilities and power at any time are greatly influenced by the existing state of electronic of that time.

If electronic components and devices of any time were big, slow and unreliable then computers of that time were also big, slow and unreliable. On the other hand fast, reliable and smaller electronic components made the computers small, reliable and fast in operations.

You know that technological developments of electronics passed through few major phases. For example, there was time when vacuum tubes were quite popular. They were freely used in majority of electronic equipment. After some time, they were replaced by transistors. Later Integrated Circuits came and set a new path for electronic developments. Various generations of computer that came into existence, are described below.

First Generation Computers (1942-1955)

First generation computers were voluminous in size. They were made using vacuum tubes. Vacuum tube was a fragile glass device that could control an amplify electronic signals.

First generation computers used the idea of execution of stored programs.

Following were the main drawbacks of first generation computers:

1. Their size was very large.

2. Speed of instruction-execution was very slow.

3. They generated lot of heart.

4. Switching through vacuum tubes was not reliable.

5. Heavy air conditioning was required.

6. Only scientists and engineers were able to use these computers and that too in limited areas due to their high cost.

7. They needed a constant maintenance, which was very expensive. The example of generation computers are ENIAC, EDSAC and UNIVAC etc.

Second Generation Computers (1955-1964)

In second generation, transistor was invented as a smaller and more reliable successor of the vacuum tube. Although transistor was invented in 1948, its application in computers started in the year 1958. The transistor was more reliable, less expensive, and smaller than the vacuum tube. It consumed very less power and produced much less heat.

A transistor is also called a solid-state devices. It is made of a material whose principal part is silicon element. It is also called semiconductor device. It performs all the functions of a vacuum tube i.e. switches circuit on and off at a very high speed. Second generation computer made use of transistors.

Apart from the above listed advantages, the second
generation computers used better devices such as card readers, printers
etc.  This generation is also important
from the point of view of language development and use. First generation
computers used machine level language or low-level language i.e. program was
written directly in binary digits, which was very cumbersome and tedious.Later
the development of assembly Language helped the programmers to some extent. The
high level language FORTRAN was also developed for this generation of
computers. This development bring the computers very close to man and made it
a very popular machine. Some of the names of second generation computers/machines are
IBM series, UNIVAC III,CDC 1400 series, Honeywell etc.

Third Generation Computers (1964-75)

The development of integrated circuit was another milestone
in the history of computer science. It was micro electronic, in which it was possible
to integrate large number of circuit elements into very small surface area
(less than 5 mm square) of silicon known as Chip. This generation was based on
Integrated Circuits (ICs) technology and the computers that were designed with
the use of integrated circuits were called third generation computers.

These computers has better storage devices and improved
input/ output devices, such as Visual Display Unit (VDU),Magnetic Ink
Character Reader (MICR) and high-speed line printers.

These computers were 10,000 times faster than the first generation computers and arithmetic and
logical operations could be performed in nano seconds (1 nano second=10^-9
seconds) It was this time, where major advancement in the field of
hardware as well as software took place. Many useful high level languages were
developed. These computers used operating system. The use of faster input and
output devices enhanced the capabilities of these computers and made
multi programming possible, in which a number of programs could be executed
simultaneously by a single processor. Some of the popular computers of this
generation were IBM 360 series,370 series, UNIVAC,HOG 9000 series etc. Some of
them are still in use.

Fourth Generation Computers (1975 Onwards)

The development of microprocessor chip that holds entire
central processing unit (CPU) on a single silicon chip led to the invention of
fourth generation computers. The technology that was used in third generation
computers in the form of integrated Circuit (IC) was known as Small-Scale
Integration (SSI). This IC contained about ten to twenty transistors on it.
Later, the Medium Scale Integration (MSI) was developed, in which it was
possible to assemble the hundred transistors on a single chip.

After this, came the era of Large-Scale Integration (LSI) in
which, it was possible to integrate 30,000 transistors on a single chip. Efforts
were made and now the era of VLSI (Very Large Scale Integration) has come, in
which millions of transistors can be assembled on single chip. Current
generation computers are fourth generation computers and are making use of VLSI
chip. This has made the size of current computer very very small. Fourth generation
of computers can be called microcomputer generation. The input/output devices
used with fourth generation computers are quite advanced. These devices are
optical readers, which can transfer the contents of CD within few microseconds
to the computers. This generation’s computers are compact, faster, and more
reliable.

Fifth Generation Computers

Till fourth generation computers, the main stress was on
hardware technology. Though these computers are faster, more accurate,
reliable, smaller in size and very cheap, still they lack thinking power. The
fifth generation computers will have thinking power and capability to make
decisions like human beings, and may prove better than man in certain aspects.
They will be more useful in the field of knowledge processing rather than in
data processing.

In fact fifth generation computers are dreams of Japanese
scientists.

They have started work in this direction few years ago. The concept
of Artificial Intelligence (AI) is being used in these type of computers. These
computers will have Knowledge Information Processing System (KIPS) rather than
the present Data/Logic Information Processing System. Japan has chosen the
PROLOG (Programming in logic) language as its operating software to
have the final machine, which will talk with human beings, see and deliver
pictures and hear man’s natural language.