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8/14/2019 Gurmail Singh

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Introduction To Computers

What is a Computer?

The word Computer comes from the wordcompute .

A computer is considered to be a calculating devicethat can perform arithmetic operation at enormous

speed.

More accurately a computer is an electronic device

used to process data.A computer can convert data into information that is

useful to people.

It is also called Data Processor.


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Components of a Computer

System

A complete computer system includes

four different parts:

Hardware

Software

DataUser


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Computer Hardware

A computer's hardware consists of

electronic devices; the parts you can see

and touch.The term "device" refers to any piece of

hardware used by the computer, such as

a keyboard, monitor, modem, mouse, etc.


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Computer Hardware

The four primary components of a computer systemare:

Input :Input devices send data and instructions tothe central processing unit.

Output: Central processing unit executes computerinstructions. Memory holds data and programstemporarily.

Processing: Output devices make processed dataavailable to the user.

Secondary Storage :Secondary storage devices store

data and programs permanently.


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Input Devices

Input devicesaccept data and instructions from theuser or from another computer system.

Also, the input devices send the data or instructions to

the processing unit to be processed into usefulinformation.

The most commonly used input devices are :

1. Keyboard ,

2. Mouse. There are other input devices, such as touch screen,

joystick, modem, scanner, and voice recognitionsystems.


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Keyboard

The keyboard looks like the typewriter. A numeric

keypad is located to the right of the keyboard. Numeric

keys have the same placement as a 10-key calculator,

which allow the operator to enter data rapidly.


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The mouse is a device that allows you to

control the movement of the insertion

point on the screen. The operator placesthe palm of the hand over the mouse and

moves it across a mouse pad, which

provides traction for the rolling ballinside the device.

Mouse


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Characteristics of Computer

Speed :

While talking about the speed of a computer,

we do not talk in terms of seconds or even

milliseconds (10-3). Our units of speed are

microseconds (10-6), the nanoseconds (10-9), and

even the picoseconds (10-12). A powerful

computer is capable of performing about 3 to 4

million simple arithmetic operations persecond.


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1. Accuracy :

The accuracy of a computer is consistently high

and the degree of a particular computer

depends upon its design. But for a particular

computer, each and every calculation is

performed with the same accuracy.


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3. Diligence :

Unlike human beings, a computer is free from

monotony, tiredness, lack of concentration,and

hence can work for hours together without

creating any error


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4. Versatility :

Versatility is one of the most wonderfulthings about a computer.

All that is required to change its talent is to slipin a new program into it.

Briefly, a computer is capable of performing

any task provided that the task can be reduced

to a series of logical steps.


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5. Power of Remembering:

A computer can store and recall any amount of

information because of its secondary storage

capability.

Every piece of information can be retained as

long as desired by the user and can be recalled

as and when necessary.


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6. No I.Q :

A computer is not a magical device. It can only

perform tasks that a human being can. It

possesses no intelligence of its own. Its I.Q. is

zero.


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7. No Feelings :

Computers are devoid of emotions. They have

no feelings and no instincts because they are

machines.

Computers cannot make judgments of their

own, their judgment is based on the

instructions given to them in the form of

programs that are written by us.

They are only as good as man makes and uses

them.

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