This document discusses the four generations of computers from the 1940s to today. The first generation used vacuum tubes and were large, expensive machines. The second generation introduced transistors, making computers smaller and faster. Integrated circuits were developed in the third generation, further miniaturizing computers. The fourth generation saw the invention of microprocessors which enabled the development of personal computers and networks like the internet. Each generation brought improvements in size, cost, speed and capabilities.

1. 1
GENERATION OF COMPUTER
Generation refer to the state of improvement in the product development
process. Similarly, we can say generation of computer refers to the state of
improvement of computer technlogy.
Computer :
Programmable machine that can store, retrieve, and process data.
Today's computers have at least one CPU that performs most calculations and
includes a main memory, a control unit, and an arithmetic logic unit. Increasingly,
personal computers contain specialized graphic processors, with dedicated
memory, for handling the computations needed to display complex graphics, such
as for three-dimensional simulations and games. Auxiliary data storage is usually
provided by an internal hard disk and may be supplemented by other media such
as floppy disks or CD-ROMs. Peripheral equipment includes input devices (e.g.,
keyboard, mouse) and output devices (e.g., monitor, printer), as well as the
circuitry and cabling that connect all the components
GENERATION OF COMPUTER :
The First Generation : 1946-1958 ( The Vacuum Tube Years)
 The First Generation Computer period starts from 1946 with ENIAC
(Electronic Numerical Integrator And Computer) and UNIVAC (Universal
Automatic Computer) developed by Presper Eckert and John Mauchly.
 Language used in first generation computer was the Machine Language.
 They were very large and prodeced a large amount of heat and they had to
be cooled down by air conditioners. However even with these huge
coolers, vacuum tubes still overheated regularly. It was time for something
new.

2. 2
 First-generation digital computers, developed mostly in the U.S. after
World War II, used vacuum tubes and were enormous
Vacuum Tube
Electron tube consisting of a sealed glass or metal enclosure from which the air has been
withdrawn.
It was used in early electronic circuitry to control a flow of electrons. In the first half of the 20th
century, vacuum tubes allowed the development of radio broadcasting, long-distance telephone
service, television, and the first electronic digital computers, which were the largest vacuum-tube
systems ever built. Transistors have replaced them in virtually all applications, but they are still
occasionally used in display devices for television sets and computers (cathode-ray tubes), in
microwave ovens, and as high-frequency transmitters on space satellites.
Features of The First Generation :
 It is very slow.
 It is very expensive.
 It is very huge(as big as the size of the room).
Limitation of The First Generation :
 Produce lot of heat.
 Not Reliable.
 Programming capacity was very slow.
 Used machine language only.
The Second Generation of Computer : 1959- 1964 (The Era Of The Transistor)
 The second generation, introduced c. 1960, used transistors and were the
first successful commercial computers.
 The language used in the second generation computer was assembly
language.

3. 3
 The second generation computers also produced a large amount of heat
and they too had to be cooled down by air conditioners
 They were smaller, faster and more efficient than the first generation
computers.
 The operating speed was comparatively high.
 Examples of second generation computer were IBM140, MARK III, LEO,
etc.
Features of The Second Generation:
 Electronic component used Transistor.
 The size became smaller than first generation computer.
 The operating speed became higher.
 The cost became low.
Limitation of The Second Generation :
 It produce heat.
 Its speed was still low.
 Memory was less.
The Third Generation of Computer : 1965- 1970 (Integrated Circuits –
Miniaturizing the Computer)
 Third-generation computers (late 1960s and 1970s) were characterized by
miniaturization of components and use of integrated circuits.
 Due to the use of ICs, the size of the computer became very small.

4. 4
 Transistor were miniaturized and placed on silicon chip called
semiconductor.
 High level languages like FORTRAN and COBOL were used.
 Example of third generation computer are ICL, CDC, IBM360, ICL 1900, etc.
Features of The Third Generation :
 The Electron component used integrated circuits
 The size became much smaller.
 The operating spedd became faster.
 The cost became cheaper than their predecessors.
The Fourth Generation of Computer : 1971- Today (The Microprocessor)
 The microprocessor chip, introduced in 1974, defines fourth-generation
computers.
 The size of computer became too small as thousands of integrated circuits
were built onto a single chip.
 The Fourth Generation of Computer could fit on a small desk or in the palm
of the hand.
 The Fourth Generation of Computer became more powerful and they could
be linked together to form a network, which led the development of
internet.
 Today’s Fourth Generation Computer are still getting smaller and more
powerful. Example of fourth generation computer are Intel 4004, Apple,
IBM 370, etc.
Features of The Fourth Generation of Computer :

5. 5
 The Electron component used Microprocessor.
 The size became much smaller than ever.
 The operating spedd became very faster.
 They are completely reliable.
Microprocessor
Miniature electronic device that contains the arithmetic, logic, and control
circuitry needed to function as a digital computer's CPU.
Microprocessors are integrated circuits that can interpret and execute program
instructions as well as handle arithmetic operations. Their development in the
late 1970s enabled computer engineers to develop microcomputers.
Microprocessors led to “intelligent” terminals, such as bank ATMs and point-of-sale
devices, and to automatic control of much industrial instrumentation and
hospital equipment, programmable microwave ovens, and electronic games.
Many automobiles use microprocessor-controlled ignition and fuel systems.
Fourth-Generation Language (4GL)
Fourth-generation computer programming language. 4GLs are closer to human
language than other high-level languages and are accessible to people without
formal training as programmers.
They allow multiple common operations to be performed with a single
programmer-entered command. They are intended to be easier for users than
machine languages (first-generation), assembly languages (second-generation),
and older high-level languages (third-generation).