COMPUTER - GENERATIONS

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Generation in computer terminology is a change in technology a computer is/was

being used. Initially, the generation term was used to distinguish between varying
hardware technologies. But nowadays, generation includes both hardware and
software, which together make up an entire computer system.

There are totally five computer generations known till date. Each generation has been
discussed in detail along with their time period and characteristics. Here approximate
dates against each generations have been mentioned which are normally accepted.

Following are the main five generations of computers

S.N. Generation & Description

1
First Generation

The period of first generation: 1946-1959. Vacuum tube based.

2
Second Generation

The period of second generation: 1959-1965. Transistor based.

3
Third Generation

The period of third generation: 1965-1971. Integrated Circuit based.

4
Fourth Generation

The period of fourth generation: 1971-1980. VLSI microprocessor based.

5
Fifth Generation

The period of fifth generation: 1980-onwards. ULSI microprocessor based

First Generation
The period of first generation was 1946-1959. The computers of first generation used
vacuum tubes as the basic components for memory and circuitry for CPU (Central
Processing Unit). These tubes, like electric bulbs, produced a lot of heat and were
prone to frequent fusing of the installations, therefore, were very expensive and could
be afforded only by very large organisations. In this generation mainly batch processing
operating system were used. Punched cards, paper tape, and magnetic tape were used
as input and output devices. The computers in this generation used machine code as
programming language.

The main features of first generation are:

Vacuum tube technology

Unreliable
Supported machine language only
Very costly
Generated lot of heat
Slow input and output devices
Huge size
 Need of A.C.
Non-portable
Consumed lot of electricity

Some computers of this generation were:

ENIAC
EDVAC
UNIVAC
IBM-701
IBM-650

Second Generation
The period of second generation was 1959-1965. In this generation transistors were
used that were cheaper, consumed less power, more compact in size, more reliable
and faster than the first generation machines made of vacuum tubes. In this
generation, magnetic cores were used as primary memory and magnetic tape and
magnetic disks as secondary storage devices. In this generation assembly language and
high-level programming languages like FORTRAN, COBOL were used. The computers
used batch processing and multiprogramming operating system.

The main features of second generation are:

 Use of transistors

Reliable in comparison to first generation computers

Smaller size as compared to first generation computers

Generated less heat as compared to first generation computers

Consumed less electricity as compared to first generation computers

Faster than first generation computers

Still very costly

A.C. needed

Supported machine and assembly languages

Some computers of this generation were:

IBM 1620
IBM 7094
CDC 1604
CDC 3600
UNIVAC 1108

Third Generation
The period of third generation was 1965-1971. The computers of third generation used
integrated circuits (IC's) in place of transistors. A single IC has many transistors,
resistors and capacitors along with the associated circuitry. The IC was invented by
Jack Kilby. This development made computers smaller in size, reliable and efficient. In
this generation remote processing, time-sharing, multi-programming operating
system were used. High-level languages (FORTRAN-II TO IV, COBOL, PASCAL PL/1,
BASIC, ALGOL-68 etc.) were used during this generation.
The main features of third generation are:

IC used
More reliable in comparison to previous two generations
Smaller size
Generated less heat
Faster
Lesser maintenance
Still costly
A.C needed
Consumed lesser electricity
Supported high-level language

Some computers of this generation were:

IBM-360 series
Honeywell-6000 series
PDP(Personal Data Processor)
IBM-370/168
TDC-316

Fourth Generation
The period of fourth generation was 1971-1980. The computers of fourth generation
used Very Large Scale Integrated (VLSI) circuits. VLSI circuits having about 5000
transistors and other circuit elements and their associated circuits on a single chip
made it possible to have microcomputers of fourth generation. Fourth generation
computers became more powerful, compact, reliable, and affordable. As a result, it gave
rise to personal computer (PC) revolution. In this generation time sharing, real time,
networks, distributed operating system were used. All the high-level languages like C,
C++, DBASE etc., were used in this generation.

The main features of fourth generation are:

VLSI technology used

Very cheap
Portable and reliable
Use of PC's
Very small size
Pipeline processing
No A.C. needed
 Concept of internet was introduced
Great developments in the fields of networks
Computers became easily available

Some computers of this generation were:

DEC 10
STAR 1000
PDP 11
CRAY-1(Super Computer)
CRAY-X-MP(Super Computer)

Fifth Generation
The period of fifth generation is 1980-till date. In the fifth generation, the VLSI
technology became ULSI (Ultra Large Scale Integration) technology, resulting in the
production of microprocessor chips having ten million electronic components. This
generation is based on parallel processing hardware and AI (Artificial Intelligence)
software. AI is an emerging branch in computer science, which interprets means and
method of making computers think like human beings. All the high-level languages
like C and C++, Java, .Net etc., are used in this generation.

AI includes:

Robotics
Neural Networks
Game Playing
Development of expert systems to make decisions in real life situations.
Natural language understanding and generation.
The main features of fifth generation are:

ULSI technology

Development of true artificial intelligence

Development of Natural language processing

Advancement in Parallel Processing

Advancement in Superconductor technology

More user friendly interfaces with multimedia features

Availability of very powerful and compact computers at cheaper rates

Some computer types of this generation are:

Desktop
Laptop
NoteBook
UltraBook
ChromeBook