Nowadays, the computer is one of the essential parts of our day to day
activities. Computers are so smart that they can also do many tasks
automatically according to the data given to them. However, computers were not
like this before. There were constant developments and innovations in computer
technology that made computers so powerful and useful. All such developments
are divided into different generations of computers.

This article discusses the generations of computers, the duration of each
generation, the technology used, advantages and disadvantages. Before we
discuss generations of computers, let us first understand what the generations
of computers are and how many generations of computers are there.
What are the generations of computers?
Generations of computers are mainly divided according to the development of
computer technology. Each generation defines the major technological
developments on which computer systems were/are based.
In the early days of development, the 'generation of computers' was intended
solely to illustrate the differences between hardware technologies. However,
nowadays the term is the conclusion of both hardware and software changes
involved in the path of computer development. In particular, the term
'generation' refers to development that changes the way computers work.
Moreover, frequent improvements were made to make computer devices more
compact in size, cheaper in price, more powerful and smarter, etc.
How many generations of computers are there?
Although the development of computer technology was started in around 1940,
the evolution of this technology began around 1946 with the first generation
of computer and continuously evolving ever since. As of now, there are
five generations of the computer.
What are the five generations of computers?
The five generations of computers are listed below:
Each of these generations of computers is also discussed below with the
necessary details and relevant images. Let us discuss each generation in
detail:
First Generation (1946 – 1959)
This is the earliest generation of computers, known as the first generation of
computers. The first generation period is considered from 1946 to 1959. During
the first generation, computers were developed using vacuum tubes as the core
technology. First-generation computers used the machine language, the
lowest-level programming language so that it could be easily processed and
understood by computers.

ENIAC, short for Electronic Numeric Integrated and Calculator, is the most
popular example of the first generation computer. Other examples include
UNIVAC, EDVAC, EDSAC, IBM-650, IBM-701, Manchester Mark 1, Mark 2, Mark 3,
etc.
Advantages of the First Generation Computers
The following are the main advantages of first-generation computers:
• Vacuum tubes were used in first-generation computers, and the
generation helped introduce computer devices.
• Due to the use of machine languages, computers of this generation
were faster as early development.
• Computers were able to perform calculations in
milliseconds.
Disadvantages of the First Generation Computers
The following are the main disadvantages of first-generation computers:
• First-generation computers were very large and could also cover an
entire room.
• Computers of this generation generated too much heat and required a
large cooling system.
• Storage capacity in computers was very low in this generation.
Second Generation (1959 – 1965)
The second generation of computers began with the widespread use of
transistors. In this generation, vacuum tubes were no longer the main piece of
technology. They were replaced by transistors. The second-generation period is
considered from 1959 to 1965. Magnetic cores (as primary memory devices) and
magnetic tapes (as secondary storage devices) were also used for memory
requirements in computers.
During the second generation, computers used assembly languages instead of
binary machine languages. Besides, early versions of high-level languages,
such as COBOL and FORTRAN, were also introduced in this generation.

The CDC-3600 and IBM-7094 are the most popular first-generation computers.
Other examples include UNIVAC-1108, IBM-7070, CDC-1604, IBM-1400 series of
computers, IBM-1600 series, IBM-7000 series, Honeywell-400, etc.
Advantages of the Second Generation Computers
The following are the main advantages of the second generation computers:
• The transistor helped to make the second generation computer slightly
smaller than the first generation computer.
• Due to magnetic core technology, computers of this generation could
store instructions in memory.
• Computers became faster, reliable, and were able to perform
calculations in microseconds.
Disadvantages of the Second Generation Computers
The following are the main disadvantages of the second generation computers:
• A cooling system was still needed in the second generation.
• Second-generation computers required maintenance at regular
intervals.
• The cost of the computer was still high; however, less than the first
generation computer.
Third Generation (1965 – 1971)
The third generation of computers was characterized by the use of integrated
circuits (ICs) in computers rather than transistors. The third generation
period is considered from 1965 to 1971. In this generation, integrated
circuits were used as the main piece of technology. The integrated circuits
were very small in size and helped to make the computer smaller than its
predecessor.
Besides, advanced input-output devices, such as a mouse, keyboard, and monitor
were introduced in this generation. Before these devices, computers used punch
cards and printouts. In terms of languages, third-generation computers used
higher-level languages such as COBOL, BASIC, ALGOL-68, PASCAL PL / 1,
FORTRAN-II to IV, etc.

Computers developed under the IBM-360 family series are the best examples of
third-generation computers. Other examples include PDP-8, PDP-11, TDC-316,
Honeywell-6000 series, ICL 2900 etc. Besides, integrated circuits are still in
use in today's generation of computers.
Advantages of the Third Generation Computers
The following are the main advantages of the third generation computers:
• Third-generation computers were smaller than previous-generation
computers, making second-generation computers portable and available for
commercial use at relatively low prices.
• Computers were fast, reliable, and could perform calculations in
nanoseconds. They also had more storage availability.
• Computers in the third generation produced less heat and became more
energy efficient than the previous generation.
Disadvantages of the Third Generation Computers
The following are the main disadvantages of the third generation computers:
• Third-generation computers also required a cooling system.
• Production and maintenance of integrated circuits were difficult at
that time.
• The price of third-generation computers was still high for personal
needs.
Fourth Generation (1971 – 1980)
The fourth-generation period is considered from 1971 to 1980. During this
generation, computers were developed using the microprocessor as the main
component of the technology. Microprocessors were also based on LSI (Large
Scale Integration) and VLSI (Very Large Scale Integration) technologies. They
were developed by assembling several integrated circuits on a single silicon
chip.
Microprocessors not only helped make computers smaller but also made them so
powerful and reliable. Due to their compact size, computers became available
for personal use during the fourth generation. Besides, high-level programming
languages such as C, C ++, DBASE, etc. were used in computers of this
generation. Time-sharing, network-based, distributed operating systems were
also used in computers of this generation.

The IBM-5100, Altair-8800, and Micral are the most popular computers of the
fourth generation computers. Other examples include PDP-11, DEC-10, IBM-4341,
STAR-1000, CRAY-1, CRAY-X-MP etc. Besides, microprocessors are still in use in
today's generation (fifth generation of computers). However, they are not
considered a core technology in the current generation.
Advantages of the Fourth Generation Computers
The following are the main advantages of the fourth generation computers:
• Due to the compact size, the computer became widely available for
commercial and personal use. It also led to the revolutionary use of personal
computers (PCs).
• Fourth-generation computers were faster, smaller, reliable, more
energy-efficient than their predecessors. Also, fourth-generation computers
had more storage availability.
• The amount of heat in fourth-generation computers was greatly
reduced. The heat produced was almost negligible and hence the air conditioner
system was no longer needed.
Disadvantages of the Fourth Generation Computers
The following are the main disadvantages of the fourth generation computers:
• The construction of VLSI circuits, and microprocessors, was complex
and required highly sophisticated technology and advanced technical skills.
• A cooling fan was included in computers instead of an air
conditioning system. These cooling fans made noises with intense use of
computers.
• Fourth-generation computers still used integrated circuits and
therefore high technical skills were required to construct and assemble these
ICs.
Fifth Generation (1980 to Present)
Fifth-generation computers are based on ULSI (Ultra Large Scale Integration)
technology, AI (artificial intelligence) software, and parallel processing
hardware. ULSI has revolutionized the development of microprocessors. Now,
about ten million electronic devices can be assembled on a single
microprocessor chip. On the other hand, AI is helping computers to react
efficiently against natural languages.
The fifth-generation period is believed to have started in 1980 and is
continuing. This means that the current generation is the fifth generation of
computers. Fifth-generation computers are still using integrated circuits to
meet various needs. However, the main technology is AI where there is still
room for improvement.

In the fifth generation, computers are particularly based on logic programming
and massively parallel computing. All high-level languages are supported in
this generation. Some such languages include C, C ++, Java, .NET, etc.
Besides, multi-threaded and distributed operating systems are in use. Common
examples of fifth-generation computers are Desktop, Laptop, Notebook,
Chromebook, Ultrabook, Tablet, etc.
Advantages of the Fifth Generation Computers
The following are the main advantages of fifth-generation computers:
• Fifth-generation computers are available in different sizes and they
can now fit on the palm as well.
• Computers have become so fast that they can handle multitasking
easily. Also, if the data given by the user is correct, then fifth generation
computers are almost 100% accurate in calculations.
• With the use of AI in the fifth generation, computers have become so
smart that they can understand human language and recognize pictures of
individuals and things. However, all these data are input on the computer or
they do so with the help of the internet. They do not have the ability to
think as human beings.
Disadvantages of the Fifth Generation Computers
The following are the main disadvantages of the fifth generation computers:
• With advanced features and accuracy, computers have also replaced
humans in various fields, increasing unemployment. They are also ruining
humans' ability to think and learn.
• Due to the widespread use of computers in the fifth generation, the
amount of wastage of computers and their parts is increasing significantly. It
negatively affects the environment.
• Computers have also become a threat to personal use and businesses as
there are various types of cybercrimes that can cause damage to personal
details as well as financial losses.
Summary
• The period of the first generation of computers is 1946 – 1959, and
the main technology used in computers was vacuum tubes.
• The period of the second generation of computers is 1959 – 1965, and
the main technology used in computers was transistors.
• The period of the third generation of computers is 1965 – 1971, and
the main technology used in computers was integrated circuits.
• The period of the fourth generation of computers is 1971 – 1980, and
the main technology used in computers was the microprocessor.
• The fifth-generation period of computers is 1980 - current, and the
main technologies used in computers are ULSI, AI software, and parallel
processing hardware.
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