Computer Generations

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

Main five generations of computers

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.

1. 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

2.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 languageslike FORTRAN, COBOL were used. The computers used batch processing and multiprogramming operating system.

The main features of second generation are:

1.Use of transistors
2.Reliable in comparison to first generation computers
3.Smaller size as compared to first generation computers
4.Generated less heat as compared to first generation computers

5.Consumed less electricity as compared to first generation computers
6.Faster than first generation computers
7.Still very costly
8.A.C. needed
9.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:

1.IC used
2.More reliable in comparison to 3.previous two generations
Smaller size
4.Generated less hea
5.Faster
6.Lesser maintenance
7.Still costly
8.A.C needed
9.Consumed lesser electricity
10.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:

1.VLSI technology used
2.Very cheap
3.Portable and reliable
4.Use of PC’s
5.Very small size
6.Pipeline processing
7. A.C. needed
8.Concept of internet was introduced
9.Great developments in the fields of networks
10.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 tenmillion
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:

1.ULSI technology
2.Development of true artificial intelligence
3.Development of Natural 5.language processing
6.Advancement in Parallel Processing
7.Advancement in Superconductor technology
8.More user friendly interfaces with multimedia features
9.Availability of very powerful and compact computers at cheaper rates

Some computer types of this generation are:

Desktop

Laptop
NoteBook
UltraBook
ChromeBook