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March 30, 2010 [GENERATION OF COMPUTER] Abdul Azeem

NTU, Pakistan 1

1. Generations of Computer

The history of computer development is often referred to in reference to the different

generations of computing devices. Each generation of computer is characterized by a major

technological development that fundamentally changed the way computers operate, resulting in

increasingly smaller, cheaper, and more powerful and more efficient and reliable devices.

These generations and the developments led to the current devices that we use today.

1.1 First Generation (1940-1956) Vacuum Tubes:-

The first computers used vacuum tubes for circuitry and magnetic drums for memory. 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. First generation computers

relied on machine language, 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.The UNIVAC and ENIAC computers are examples of first-generation computing devices.

Fig. 1 First generation computers used vacuum tubes.

1.2 Second Generation (1956-1963) Transistors:-

Transistors replaced vacuum tubes and ushered in the second generation of computers.

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.

It was a vast improvement over the vacuum tube. Second-generation computers still relied on

punched cards for input and printouts for output. 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.

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Fig. 2 Second generation computers used transistors.

The first computers of this generation were developed for the atomic energy industry.

1.3 Third Generation (1964-1971) Integrated Circuits:-

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 keyboards and monitors and

interfaced with an operating system, which allowed the device to run many different applications

at one time with a central program that monitored the memory. Computers for the first time

became accessible to a mass audience because they were smaller and cheaper than their

predecessors. Manufacturers of third generation computers are producing a series of similar and

compatible computers. This allows programs written for one computer model to run on larger

models of the same series.

Fig. 3 Third generation computers used microcircuits.

1.4 Fourth Generation (1971-Present) Microprocessors:-

The microprocessor brought the fourth generation of computers, as thousands of

integrated circuits were built onto a single silicon chip. The Intel 4004 chip, developed in 1971,

located all the components of the computer — from the central processing unit and memory to

input/output controls — on a single chip. In 1981 IBM introduced its first computer for the home

user, and in 1984 Apple introduced the Macintosh. Microprocessors also moved out of the realm

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of desktop computers and into many areas of life as more and more everyday products began to

use microprocessors. As these small computers became more powerful, they could be linked

together to form networks, which eventually led to the development of the Internet. Fourth

generation computers also saw the development of GUIs, the mouse and handheld devices.

Fig. 4 Fourth generation desktop (personal) computer

1.5 Fifth Generation (Present and Beyond) Artificial Intelligence:-

Fifth generation computing devices, based on artificial intelligence, are still in

development, though there are some applications, such as voice recognition, that are being used

today. The use of parallel processing and superconductors is helping to make artificial

intelligence a reality. Quantum computation and molecular and nanotechnology will radically

change the face of computers in years to come. The goal of fifth-generation computing is to

develop devices that respond to natural language input and are capable of learning and self-

organization.

Fig. 5 Fifth generation based on artificial intelligence

The project was to create the computer over a ten year period, after which it was considered

ended and investment in a new, Sixth Generation project, began. Opinions about its outcome are

divided: Either it was a failure, or it was ahead of its time.

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2. Classifications of computer

Here we are going to introduce different classifications of computers one by one. We will discuss

what are in classifications and what job they perform.

2.1 Servers:-

A server controls access to network resources and provides centralized storage. The types of servers are following.

2.1.1 Super computers:-

The biggest in size, the most expensive in price than any other is classified and known as

super computer. It can process trillions of instructions in seconds. This computer is not used as a

PC in a home neither by a student in a university. Governments specially use this type of

computer for their different calculations and heavy jobs. Different industries also use this hugecomputer for designing their products. In most of the Hollywood’s movies it is used for animation

purposes. This kind of computer is also helpful for forecasting weather reports worldwide,

Nuclear energy research, Aircraft design, automotive design, and Online banking to control

industrial units.

The examples of supercomputers are CRAY-1, CRAY-2, Control Data CYBER 205 and ETA A-10

etc.

2.1.2 Mainframes:-

Another giant in computers after the super computer is Mainframe, which can also

process millions of instruction per second and capable of accessing billions of data. This

computer is commonly used in big hospitals, air line reservations companies, and many other

huge companies prefer mainframe because of its capability of retrieving data on a huge basis.

This is normally too expensive and out of reach from a salary-based person who wants a

computer for his home. This kind of computer can cost up to thousands of dollars. The

mainframe computers are used in large organizations such as banks, airlines and universities etc.

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IBM is the major manufacturer of mainframe computers. The examples of mainframes are IBM

S/390, Control Data CYBER 176 and Amdahl 580 etc.

2.2 Minicomputers:-

These are smaller in size, have lower processing speed and also have lower cost than

mainframe. The capabilities of a minicomputer are between mainframe and personal computer.

These are the computers, which are mostly preferred by the small type of business personals,

universities etc. The first minicomputer was introduced in the mid-1960s by Digital Equipment

Corporation (DEC). After this IBM Corporation, Data General Corporation and Prime Computer

also designed the mini computers.

2.3 Personal computers / Micro Computers:-

Almost all the computer users are familiar with the personal computers. Microprocessor

is used in this type of computer. This is the computer mostly preferred by the home users. These

computers are lesser in cost than the computers given above and also, small in size; they are also

called PCs in short for Personal computers. Today this is thought to be the most popular

computer in all.

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Personal computers are available in two models. These are: Desktop PCs and Tower PCs.

Microcomputers are further divided into following categories.

2.3.1 Notebook computers / Laptop Computers:-

Having a small size and low weight the notebook is easy to carry to anywhere. A student

can take it with him/her to his/her university in his/her briefcase. The approach of this computer

is also the same as the Personal computer. It can store the same amount of data and having a

memory of the same size as that of a personal computer. Laptop computer is also available with

the same processing speed as the most powerful personal computer. One can say that it is the

replacement of personal desktop computer.

2.3.2 Workstations:-

Workstations are special single user computers having the same features as personal

computer but have the processing speed equivalent to minicomputer or mainframe computer. A

workstation computer can be fitted on a desktop. Scientists, engineers, architects and graphic

designers mostly use these computers. Workstation computers are expensive and powerful

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computers. These have advanced processors, more RAM and storage capacity than personal

computers. These are usually used as single-user applications.

2.3.3 Network computers:-

Network computers are also version of personal computers having less processing power,

memory and storage. Some types of network computers have no storage. The network computers

are designed for network, Internet or Intranet for data entry or to access data on the network. The

network computers depend upon the network’s server for data storage and to use software .

Network computers are cheaper to purchase and to maintain than personal computers.

2.3.4 Handheld Computers:-

In the mid 1990s, many new types of small personal computing devices have been

introduced, referred to as handheld computers. The handheld computers sometimes called Mini-Notebook Computers. It can fit in one hand while you can operate it with the other hand due to

its reduced size. Similarly it also has small keyboard. The handheld computers are preferred by

business traveler. Some handheld computers have a specialized keyboard.

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2.4 Embedded Computers:-

These are Special-purpose computers that functions as a component in a larger product.

These are the small computers in which specific program are installed or used. These are devices

in which program is installed for the specific purpose. These are used for one or multiple

purposes. The examples of these types of computers are ATM Machines, Refrigerators, and

Game Consoles etc.

2.4.1 Game Consoles:-

These types of embedded computers are specific for games only. These are Mobile

computing devices designed for single-player or multiplayer video games.

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