The document discusses the five generations of computers. The first generation used vacuum tubes, were large and expensive. The second generation used transistors, making computers smaller and more efficient. The third generation used integrated circuits, allowing for smaller size and operating systems. The fourth generation used microprocessors and gave rise to personal computers. The fifth generation uses artificial intelligence and parallel processing. Each generation brought improvements in size, cost, speed and capabilities.

1. Computer Generations
A generation refers to the state of improvement in the development of the product This term is also
used in the different advancements of computer technology.Each of the five generations of
computers is characterized by a major technological development that fundamentally changed the
way computers operate, resulting in increasingly smaller, cheaper, more powerful and more
efficient and reliable computing devices.
First Generation
Time Period: The first generation computers were used during 1942-1955.
Technology Used: The first computers used vacuum tubes for circuitry and magnetic drums for
memory, and were often enormous, taking up entire rooms. They were very expensive to operate
and in addition to using a great deal of electricity, generated a lot of heat, which was often the
cause of malfunctions.
Programming Language: First generation computers relied on machine language, the lowest-
level programming language understood by computers, to perform operations, and they could only
solve one problem at a time. Input was based on punched cards and paper tape, and output was
displayed on printouts.
Advantages
 Vacuum tubes were the only electronic component available during those days.
 Vacuum tube technology made possible to make electronic digital computers.
 These computers could calculate data in millisecond.
Disadvantages
 The computers were very large in size.
 They consumed a large amount of energy.
 They heated very soon due to thousands of vacuum tubes.
 They were not very reliable.
 Air conditioning was required.
 Constant maintenance was required.
 Non-portable.
 Costly commercial production.
 Limited commercial use.
 Very slow speed.
 Limited programming capabilities.
 Used machine language only.
 Used magnetic drums which provide very less data storage.
 Used punch cards for input.
 Not versatile and very faulty.
Some computers of this generation were:

2.  ENIAC
 EDVAC
 UNIVAC
 IBM-701
 IBM-650
Second Generation
Time Period: The period of second generation was 1959-1965.
Technology Used: Transistors replaced vacuum tubes and ushered in the second generation of
computers. The transistor was invented in 1947 but did not see widespread use in computers until
the late 1950s. The transistor was far superior to the vacuum tube, allowing computers to become
smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation
predecessors. Though the transistor still generated a great deal of heat that subjected the computer
to damage, it was a vast improvement over the vacuum tube. Second-generation computers still
relied on punched cards for input and printouts for output.
Programming Language: Second-generation computers moved from cryptic binary machine
language to symbolic, or assembly, languages, which allowed programmers to specify instructions
in words. High-level programming languages were also being developed at this time, such as early
versions of COBOL and FORTRAN. These were also the first computers that stored their
instructions in their memory, which moved from a magnetic drum to magnetic core technology.
Advantages
 Smaller in size as compared to the first generation computers.
 The 2nd generation Computers were more reliable
 Used less energy and were not heated.
 Wider commercial use
 Better portability as compared to the first generation computers.
 Better speed and could calculate data in microseconds
 Used faster peripherals like tape drives, magnetic disks, printer etc.
 Used Assembly language instead of Machine language.
 Accuracy improved.
Disadvantages
 Cooling system was required
 Constant maintenance was required
 Commercial production was difficult
 Only used for specific purposes
 Costly and not versatile
 Punch cards were used for input.

3. Some computers of this generation were:
 IBM 1620
 IBM 7094
 CDC 1604
 CDC 3600
 UNIVAC 1108
Third Generation
Time Period: The period of third generation was 1965-1971.
Technology Used: The development of the integrated circuit was the hallmark of the third
generation of computers. Transistors were miniaturized and placed on silicon chips, called
semiconductors, which drastically increased the speed and efficiency of computers.
Instead of punched cards and printouts, users interacted with third generation computers through
keyboardsand monitors and interfaced with an operating system, which allowed the device to run
many differentapplications at one time with a central program that monitored the memory.
Programming Language: The language used was high-level programming languages, such as
C, C++, and Java. Moving away from the cryptic commands of Assembly Language, a third
generation (programming) language introduced significant enhancements to second generation
languages, primarily intended to make the programming language more programmer-friendly.
Some computers of this generation were:
 IBM-360 series
 Honeywell-6000 series
 PDP(Personal Data Processor)
 IBM-370/168
 TDC-316
Advantages
 Smaller in size as compared to previous generations.
 More reliable.
 Used less energy
 Produced less heat as compared to the previous two generations of computers.
 Better speed and could calculate data in nanoseconds.
 Used fan for heat discharge to prevent damage.
 Maintenance cost was low because hardware failure is reare.
 Totally general purpose
 Could be used for high-level languages.

4.  Good storage
 Versatile to an extent
 Less expensive
 Better accuracy
 Commercial production increased.
 Used mouse and keyboard for input.
Disadvantages
 Air conditioning was required.
 Highly sophisticated technology required for the manufacturing of IC chips.
Fourth Generation
Time Period: The period of fourth generation was 1971-1980.
Technology Used: The fourth generation computers started with the invention of
Microprocessor. The Microprocessor contains thousands of ICs . The technology of integrated
circuits improved rapidly. The LSI (Large Scale Integration) circuit and VLSI (Very Large Scale
Integration) circuit was designed. 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.
Programming Language: Often abbreviated 4GL, fourth-generation languages are
programming languages closer to human languages than typical high-level programming
languages. 4GLs are more programmer-friendly and enhance programming efficiency with usage
of English-like words and phrases, and when appropriate, the use of icons, graphical interfaces
and symbolical representations.
Some computers of this generation were:
 DEC 10
 STAR 1000
 PDP 11
 CRAY-1(Super Computer)
 CRAY-X-MP(Super Computer)
Advantages
 More powerful and reliable than previous generations.
 Small in size
 Fast processing power with less power consumption
 Fan for heat discharging and thus to keep cold.
 No air conditioning required.
 Totally general purpose

5.  Commercial production
 Less need of repair.
 Cheapest among all generations
 All types of High level languages can be used in this type of computers
Disadvantages
 The latest technology is required for manufacturing of Microprocessors.
Fifth Generation
Time Period: The period of fifth generation is 1980-till date.
Technology Used: n 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.
Programming Language: The fifth-generation languages, or 5GL are programming languages
that contain visual tools to help develop a program. A good example of a fifth generation
language is Visual Basic. Languages used for artificial intelligence and neural networks.
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