TYPES OF

COMPUTER

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By Sikander Shahzad

Lecturer (Computer Science)

Types of Computers based on

Principles of Operation

There are three different types of computers according

to the principles of operation. Those three types of

computers are:

Analog Computers

Digital Computers

Hybrid Computers

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Analog Computers

Analog Computer is a computing device that works on

continuous range of values. The results given by the

analog computers will only be approximate since they

deal with quantities that vary continuously. It generally

deals with physical variables such as voltage, pressure,

temperature, speed, etc

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Analog Computer

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On the other hand a digital computer operates on digital data

such as numbers. It uses binary number system in which there

are only two digits 0 and 1. Each one is called a bit.

The digital computer is designed using digital circuits in which there

are two levels for an input or output signal. These two levels are

known as logic 0 and logic 1. Digital Computers can give more accurate

and faster results.

Digital computer is well suited for solving complex problems in

engineering and technology. Hence digital computers have an

increasing use in the field of design, research and data processing.

Digital Computer

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Digital Computer

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Hybrid Computer

A hybrid computer combines the desirable features of analog

and digital computers. It is mostly used for automatic

operations of complicated physical processes and machines. Now-a-

days analog-to-digital and digital-to-analog converters are used for

transforming the data into suitable form for either type of

computation.

For exa ple, i hospital’s ICU, a alog devices ight easure the patients temperature, blood pressure and other vital signs. These

measurements which are in analog might then be converted into

Numbers and supplied to digital components in the system. These

co po e ts are used to o itor the patie t’s vital sig a d se d signals if any abnormal readings are detected. Hybrid computers are

mainly used for specialized tasks

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Hybrid Computer

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Types of Computers based on

Configuration.

On the basis of configuration that is

architecture, processing, power, size of main

memory and other capabilities, ca computer can

be divided in the following classes.

Super Computer.

Mainframe Computer.

Mini Computer.

Micro Computer.

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Super Computer

These are the

Largest.

Fastest.

Expensive.

Can handle over 10,000 users.

Parallel Processing.

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USE OF SUPERCOMPUTER: Super comptuers are used for solving complex application such

as Global Weather Forecasting. Creating graphic images,

engineering design and testing, space exploration and other

problems where it is necessary to process huge quantities

of data quickly.

Cost: Several million dollars.

Speed:

60 billion instructions per second.

Size: Automobile Sized.

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Mainframe Computer

Mainframe computer is usually slower, less

Powerful and less expensive than super

Computer.

Mainframe computer can handle over hundreds

of users.

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USE OF MAINFRAME COMPUTER:

Mainframe Comupter are useful for dealing with large over

changing collection of data that are accessed by many users

Simultaneously such as banks, airlines, railways.

Cost:

Several hundred thousands dollars.

Speed:

250 million instructions per second.

Size:

Refrigerator Sized.

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Mini Computer

Mini computers are lower to mainframe

computers in terms of speed and storage

capacity. They are also less expensive than

mainframe computers. Some of the features of

mainframes will not be available in mini

computers. Hence, their performance also will

be less than that of mainframes.

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USE OF MINI COMPUTER:

Tele communications.

Cost:

25000 Dollars to Over 150,000 Dollars.

Speed:

150 million instruction per second

Size:

Filling Cabinet size.

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Micro Computer

The invention of microprocessor (single chip

CPU) gave birth to the much cheaper micro

computers. They are further classified into

• Personal Computers

• Laptop Computers

• Handheld Computers(PDAs)

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Personal Computer

They are usually easier to use and more

affordable. They are normally intended for

individual users for their word processing and

other small application Requirements.

Desktop.

Tower.

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Laptop Computer

Laptop computers are portable computers. They

are lightweight computers with a thin screen.

They are also called as notebook computers

because of their small size. They can operate on

batteries and hence are very popular with

travellers. The screen folds down onto the

keyboard when not in use

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Hand Held Handheld computers or Personal Digital

Assistants (PDAs) are pen-based and also battery-

powered. They are small and can be carried

anywhere. They use a pen like stylus and accept

handwritten input directly on the screen. They are

not as powerful as desktops or laptops but they are

used for scheduling appointments,storing addresses

and playing games. They have touch screens which

we use with a finger or a stylus.

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