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Computer Generations
The period, during which the evolution of computer took
place, can be divided into five
distinct phases known as generations of computers.
First Generation Computers (1940-1956)
Second Generation Computers (1956-1963)
Third Generation Computers (1964-1971)
Fourth Generation Computers (1971-present)
Fifth Generation Computers (present-
beyond)
1. First Generation Computers: Vacuum
Tubes (1940-1956)
First generation computers are characterized by the
use of vacuum tube. A vacuum tube
was a fragile glass device, which used filaments as a
source of electronics. It could
control and amplify electronic signals. These vacuum
tubes were used for calculation as
well as storage and control. The first general purpose
programmable electronic computer
, 2
was the Electronic Numerical Integrator and
Computer (ENIAC), built by J. Presper
Eckert and John V. Mauchly at the University of
Pennsylvania. The ENIAC was 30-50
feet long, weighed 30 tons, contained 18,000
vacuum tubes, 70,000 registers, 10,000
capacitors and required 150,000 watts of electricity.
First generation computers were too
bulky in size which required large room for
installation and they used to emit large
amount of heat, so air-condition was must for the
proper working of computers. Programs
written in high level programming languages
retranslated into assembly language or
machine language by a compiler. Assembly language
program retranslated into machine
language by a program called an assembler
(assembly language compiler).
Before ENIAC was finished, Von Neumann designed
the Electronic Discrete Variable
Automatic Computer (EDVAC) with a memory to hold
both a stored program as well as
data. This enabled much faster operation since the
computer had rapid access to both data
and instructions. The other advantages of storing
instruction were that computer could do
Computer Generations
The period, during which the evolution of computer took
place, can be divided into five
distinct phases known as generations of computers.
First Generation Computers (1940-1956)
Second Generation Computers (1956-1963)
Third Generation Computers (1964-1971)
Fourth Generation Computers (1971-present)
Fifth Generation Computers (present-
beyond)
1. First Generation Computers: Vacuum
Tubes (1940-1956)
First generation computers are characterized by the
use of vacuum tube. A vacuum tube
was a fragile glass device, which used filaments as a
source of electronics. It could
control and amplify electronic signals. These vacuum
tubes were used for calculation as
well as storage and control. The first general purpose
programmable electronic computer
, 2
was the Electronic Numerical Integrator and
Computer (ENIAC), built by J. Presper
Eckert and John V. Mauchly at the University of
Pennsylvania. The ENIAC was 30-50
feet long, weighed 30 tons, contained 18,000
vacuum tubes, 70,000 registers, 10,000
capacitors and required 150,000 watts of electricity.
First generation computers were too
bulky in size which required large room for
installation and they used to emit large
amount of heat, so air-condition was must for the
proper working of computers. Programs
written in high level programming languages
retranslated into assembly language or
machine language by a compiler. Assembly language
program retranslated into machine
language by a program called an assembler
(assembly language compiler).
Before ENIAC was finished, Von Neumann designed
the Electronic Discrete Variable
Automatic Computer (EDVAC) with a memory to hold
both a stored program as well as
data. This enabled much faster operation since the
computer had rapid access to both data
and instructions. The other advantages of storing
instruction were that computer could do
