Chapter - 1 - Weebly · Web viewFunction Keys: These are F1, F2….. F12. They perform special functions. You will learn about them later. MOUSE The computer mouse is called so because

59

Chapter - 1Computer Concepts

Learning Outcomes

On completing this chapter you will be able to:

1. Explain the advantages and functions of a computer.2. Identify the different components of a computer.3. Switch ON and switch OFF the computer.4. Use the keyboard and mouse to perform the basic functions on a computer.5. Describe the functions of Operating Systems.6. List the Do’s and Don’ts of using a computer.

Introduction to Computers

Hello Computer Jee!

© Educomp Solutions Ltd.

Yes sure. It is true computers help us in our work. Computers have brought a lot of changes in our life. I shall help you to learn to

use computers.

Computer Jee, we have now got Computers in our school. We are

very excited. They say that computers help us in our work.

They say that computers work very fast…! I want to learn about

Computers.

59

Is Computer a Machine?


No Computer Jee. It is very difficult to think of it. How can I go to

Bangalore from my village if there is no bus? It is unthinkable.

Tell me what is a Machine? Can you give me some examples of

machines?

A machine is a device which helps us in our work. Sewing machine, car, bus, and TV are all examples of machines. They

make our work easier. Sewing machines helps us to stitch clothes. Cars and buses

help us travel faster. TV gives us news and entertainment.

Can you imagine how our life would be without such machines?

A Bicycle A Sewing Machine A Car

Examples of Machines

59© Educomp Solutions Ltd.

Oh…! Computer Jee. It happened when I was

watching a cricket match. The TV got switched off. We were all very disappointed!

Yes. Machines have become very useful in making our life

comfortable. Now tell me what happens if the power supply goes

off when you are watching TV?

The TV got switched off because TV is a machine which works on electricity.

There are machines which work on electricity. However, there are also

machines which do not need electricity to work.

Yes. Computer Jee. A bicycle and a sewing machine do not

need electricity to work.

Give me some examples of machines which work on

electricity.

Radio, Mixer, Television, Water Pump, Computer…


You are right.

A Computer is a machine which works on electricity.

Mixer Juicer Television Computer

Examples of Machines which work on electricity

Activity:Draw pictures of a few machines that you have seen in your village/town.

59

In the same way, when you switch on the Computer, you have to instruct the Computer what to do. It is just like when your teacher instructs you to do your work, and you follow her instructions. A Computer however, does not understand human language. It understands a special language made only for Computers. So the Computer needs to be given instructions in a special Computer language. Based on those instructions, the Computer does its work.


No, Computer Jee. They do not work on their own.

I have to switch ON & switch OFF the TV.

I have to peddle the bicycle…

Now tell me does a machine work on its own? Take for

example, a TV or a bicycle.

Yes, and after you switch on the TV, you have to use the buttons on your TV to change the channels or control

the volume. Similarly, when you peddle the bicycle you have to

control the handle so that you move in the direction you want.

In computer language, instructions or orders given to a computer are also called COMMANDS. In the coming sections we will see how to give

59

When the computer was first made, it was used as a calculator. Today, the computer is used to do many other things, such as writing letters, drawing beautiful pictures, and even playing games!

So, What is a Computer?A computer is a machine that accepts information and works on it based on a sequence of instructions.


What work does a Computer do?

The word C-O-M-P-U-T-E-R is made from the word

‘COMPUTE’ which means to calculate.

Have you seen a calculator? This is how a calculator works. Suppose you want to add 6 and 9, you press the following buttons (also called keys): 6 + 9 =

When you press these buttons, the display screen shows the answer as 15. You can perform many mathematical calculations using a calculator, such as multiplication, division, and subtraction.

A Calculator

Display Screen

Buttons (Keys)

59

Components of a Computer

What is Hardware?


A Computer has two main parts:

HARDWARE and SOFTWARE

Hardware and Software?

What are these, Computer Jee?

You have seen the computer in your School lab.

Did you touch it? How did it feel?

Yes Computer Jee. It is like a TV.

I also saw some box-like things, and some wires.

A Computer = Hardware + Software

59

Just like our bodies have different parts such as hands, legs, eyes, nose and mouth. Similarly, a computer has different parts such as, the monitor, keyboard, printer, mouse, speakers and CPU.

These parts of a computer (also called DEVICES) together make up the HARDWARE of a computer.

Types of Hardware


Good! These parts of a computer which you can touch and feel are called Hardware.

Our body has different parts. Each part has different function. Our hands help us to work. Our legs

help us to walk. Likewise, a Computer also has different parts that do different functions (tasks).

Computer Jee, please explain it to me in detail.


OK…! Suppose, your teacher asks you a question, ‘How many states are there in

India?’

Can you name the parts of your body which are mainly used to answer this

question?

I hear the question with my ears.I think of the answer in my mind.I tell the answer using my mouth.

Hearing Thinking Answering

How many states in India..?

28

Input Processing Output

59


Suppose your teacher asks you to add 99 and 22. What do you do? You quickly write down these numbers on your notebook and add them together.

Similarly when you instruct the Computer to add 99 and 22, the Computer writes down (or stores) the numbers in a place called MEMORY( we will learn more about this later in the chapter). It also notes that it is supposed to carry out addition on these numbers. It then adds them together and finds the answer. All this is done by the CENTRAL PROCESSING UNIT (CPU) of the Computer. It looks like a rectangular box.

A CPU handles information, performs calculations and tells other parts what to do.

When your teacher tells you to do something, you hear from your ears. A Computer does not have ears, so how can you give instructions to a Computer? A Computer receives instructions with the help of INPUT DEVICES.

Keyboard and Mouse are examples of Input Devices. Why are these called INPUT devices? It is because, the instructions are being sent through them INTO the computer.

INPUT DEVICES: Keyboard and Mouse

Central Processing Unit

Now that you have found the answer to your teacher’s question, you tell the answer using your mouth. Similarly, a Computer also gives out the information with the help of OUTPUT DEVICES.

Monitor and speakers are examples of output devices. Why are these called OUTPUT devices? They are called output devices because these are parts through which the output is received from the computer.

OUTPUT DEVICES: Monitor and Speakers


HARDWARE = Input Devices + CPU + Memory + Output

Activity:Have you seen a sugarcane crushing machine? What is the input? What is the output? What are the input and output devices used? Where is the processing unit?

Fill in the blanks with the correct answer:

Sugarcane Sugarcane Juice Sugarcane Crusher Glass Sugarcane Tray

59

More about INPUT DEVICES

KEYBOARD

A keyboard looks similar to a typewriting machine. Whatever you type using a keyboard, appears on the monitor of the computer.

It has small parts that look like buttons. But remember to call them ‘keys’, not buttons.

The keyboard is used to type numbers, alphabets, and symbols (also called ‘special characters’) such as # $ % & @ +

There are different types of keys on the keyboard.


Function Keys F1 - F12

Numeric Pad

Arrow KeysAlphabet Keys A – Z

Number Keys 0 – 9

59

1. Alphanumeric Keys: They are used to write alphabets, numbers and other symbols. For example, A, Z, 1, 9, @, $, etc.

2. Special purpose Keys: Some of the commonly used special purpose keys are the Enter key, Ctrl(Control) key, Space bar key, Shift key, Alt(Alternative) key, Del key, Esc(Escape) key, Print Screen key, Caps(Capitals) Lock key.

3. Function Keys: These are F1, F2….. F12. They perform special functions. You will learn about them later.


We type letters on the screen using the alphabet keys. And we type numbers using the number keys. You will learn about the other keys later.

What is the function of each of these keys?

Activity:

Observe your keyboard carefully.1. How many keys have alphabets on them? ____________________2. How many keys have numbers on them? _____________________3. Press the keys in order from A to Z.4. Press the keys to spell you name.

59

MOUSE

The computer mouse is called so because it looks similar to a real mouse.

There are different types of computer mouse. Some have 2 buttons. Some have 3 buttons. Each button has a specific function.

When you press a button it makes a ‘Click’ sound.

The mouse is kept and moved on a ‘mouse pad’.

When you move the mouse an arrow mark called ‘mouse pointer’ moves on the screen of the computer.

How to hold a computer mouse?© Educomp Solutions Ltd.

A Real Mouse A Computer Mouse

A Mouse Pointer

Opens a list of options.

A computer mouse has three main parts. LEFT ButtonRIGHT BUTTONSCROLL Wheel

59

Palm rests on mouse body. Index finger rests on left button and middle finger on right button. Wrist on table top Other fingers grasp the sides of the mouse. Mouse rests on mouse pad or smooth surface.

What Can You Do With a Mouse?

Mouse Action Diagram How to do it?Left-Click (Once) Press the left button once.

Double-Click (Always Left)

Press the left button twice in quick succession (quickly).

Right-Click (Once) Press the right button once.

Click and Drag (Left) Press the left button. While keeping it pressed move the mouse pointer to a different location, and then release the button.

Scroll Wheel (Roll) Move the wheel up or down with your index finger.

We will learn to use these mouse actions in the later section.


Middle Finger

Palm

Index Finger

Wrist

59


Activity:

1. Hold the mouse properly as explained above.2. Turn it around. Do you see a light coming out of it? Put the mouse back

on the mouse pad.3. Holding the mouse as shown above, press the left mouse button using

your index finger. 4. Holding the mouse in the same way, click the right mouse button using

the middle finger. 5. Now, click the left button twice in quick succession.6. Keeping the left mouse button pressed move your mouse to the right

about 2 – 3 inches. Now release the left mouse button.

59

More about the CENTRAL PROCESSING UNIT

The rectangular box in your computer system is commonly known as the ‘Central Processing Unit (CPU)’.

The main component inside the CPU is the Processor. This is in the form of a chip. A chip is made of a special kind of material called as ‘semi-conductor’. It is embedded (surrounded) with an electronic circuit. Refer to the picture given below.

The CPU is like the brain of a computer, and this is where most of the work is performed. As explained earlier, the CPU performs the following functions:


1. Receives instructions from the input devices2. Stores the information and instructions in the memory (just

like you write down the instructions on your note book!)3. Performs all computations (working out)4. Sends the information to the output devices

Processor Chip

CPU Power Button

59

More about MEMORYThere are three basic types of Computer memory:

1. Random Access Memory (RAM)2. Read Only Memory (ROM)3. Storage Devices

What is Random Access Memory?As explained in the example earlier, when your teacher asks you to add 99 and 22, what do you do? You quickly write down these numbers on your notebook and add them together.

Similarly when you instruct the Computer to add 99 and 22, the CPU writes down (or stores) the numbers in a place called MEMORY. It also notes that it is supposed to carry out addition on these numbers. The CPU now adds the 2 numbers and writes the result on the memory.

This memory where the Computer stores the information, while it is working on the instructions given by the user, is called Random Access Memory (RAM).

Coming back to the above example, when you are done with your calculation, you read the answer from your notebook and tell it to your


CPU

59

teacher. Similarly, the CPU reads the answer from the RAM and sends it to the output device.

Thus, we can see that information can both be written on and read from the RAM.

The Random Access Memory (RAM) is temporary. Once the Computer is switched off, it cannot remember what it had stored in the RAM. It is just like when your teacher erases the blackboard after writing on it.

What is Read Only Memory?The ROM contains important commands for the Computer to function. These commands remain stored on the ROM even when the computer is switched OFF.

As the name suggests, the computer can only READ from a Read Only Memory (ROM). No changes can be made on the ROM.

What are Storage Devices?


The Computer is very smart. But as you said, all the information on RAM gets erased when the Computer is switched OFF. Is

there any way the information can remain on the Computer

even when it is switched OFF?

Yes! There is something called Storage Devices that help the Computers

to store all the information permanently.

59

Say for example, you are typing a letter to your cousin using the Computer. As explained earlier, the CPU reads the alphabets that you type and stores them in the RAM. Now what would happen if there was a power failure? The Computer will get switched OFF and you would lose all the information that you typed.

Here is what you can do to prevent the information from getting lost. Just like the Computer stores (writes) the information on the RAM, you can store the information on a Storage Device. This storing of information by the user on a storage device is called SAVING. Once you have saved your information on a storage device, you can use (open) it whenever you want. It is just like writing on your notebook, and then opening your notebook to read it whenever you want.

Storage devices can store large amount of information PERMANENTLY. Hard disks, CD-ROMs and Pen Drives are examples of Storage Devices.

Hard Disk

A hard disk is a storage device located inside the CPU box. You can store

large amount of data in a Hard Disk. The information stored in Hard disk is

preserved even when the computer is switched off.


59

The inside view of a Hard Disk

Compact Disk (CD)


Compact Disks or CDs are in the form of a circular plate that can store large amount of data.

CD Drive

CPU

CD

59

Pen Drive

This storage device can be carried in pocket like a

pen therefore it is call PEN- DRIVE. It is used to store

dataA pen drive is a pen-shaped device that can

store data. Due to its shape it is also called a thumb-drive.

You can read from and write on the pen drive by inserting it into the USB

slot as shown here.

Inserting a Pen Drive into the USB slot


To write on or read from a CD, you must insert the CD into the CD drive of the computer. The CD drives are very delicate. You must ask your teacher for guidance when using a CD drive.

Pen Drive

USB Slot

59

More about OUTPUT DEVICES

MONITORA monitor looks like a TV where you can view information. The monitor has a

Power Button. It is used to ‘Switch ON’ or ‘Switch OFF’ the monitor. These

days monitors come in different shapes and sizes.

Normal Monitor Flat Screen Monitor

PRINTERA Printer is an output device that helps you to print information on paper.

You can print letters, pictures etc. on paper using a printer.


Activity: Observe your monitor and find out the ON/OFF button.

59

SPEAKERS Speakers are output devices that allow you to hear sound from your

computer. There are buttons or knobs on the speakers which help you to

adjust the volume.

Speakers


59

What is SOFTWARE?

When your teacher asks you to do a problem, you hear it, understand it and start solving it. But in the same way if you talk to a computer, it cannot un-derstand what to do. A computer cannot understand human language. It can only understand a special language which has specifically been created for the Computers.

A software is a set of instructions that tells the Computer what to do in a lan-guage that the Computer understands. Software is written in a computer language by programmers.

How does the software get inside the Computer? Most software come in CDs today. The CD is inserted into the CD drive of the Computer. The CPU reads the instructions on the CD and writes (saves) them onto the hard disk of the Computer. This act is also referred to as ‘Loading the Software’ or ‘Installing the Software’ on the Computer.


Computer Jee, You said that a Computer has two components

Hardware and SoftwareSo, what is Software?

While Hardware represents the physical parts of a Computer,

Software is something that makes the Hardware work for

us.

59

Types of SoftwareOperating Systems: Operating systems are the most important type of software in a Computer.

Operating systems control the working of a computer. Operating SystemsIt receives commands from input devices. It then and then allots performs the tasks basedto the related components of the CPU on those commands. It then sends result produced by CPUthe result to the output devices. Thus, Operating, Operating Systems manage and control all the devices of the computer system.

Operating Systems also control the working of other software. Imagine what happens when two of your friends want to sit on the same chair in the classroom. There will be a fight between them. In this situation, the teacher will instruct those two, where to sit. Similarly an Operating System makes sure there is no conflict between any of the computer resources (hardware and software)

When you switch ON your computer, it is the Operating System that first appears on your screen. Windows98, Windows XP, Windows Vista, Linux are some examples of Operating Systems.


Think of hardware as a train. Operating Systems areis like a

train drivers who are is responsible for driving the

engine.

59

Application Software: They are group of programs written to perform a specific taskThe Application Software enables the users to carry out certain specific tasks. Application Software are also called PROGRAMS.

For example, a word processing (typing) software helps you to create text documents; a drawing software helps you to draw and paint. Game software helps you to play games.

Application software cannot work in the absence of an Operating System.


Think of Application software as food sellers and book sellers in the train.

They make sure we get what we want when we are in the train. If we want food, we call the food seller and he

gives us food. Similarly, if we want to draw a picture, we open the Drawing

Software, which helps us to draw.

59

Activity:

1. A Computer system has 2 main components : _________________ and

___________

2. The hardware can be divided into 4 categories, namely :

I _ P _ T DEVICE

PR_ _ E_ _ I _ G DEVICE

O_ _ PU _ DEVICE

3. Identify the components given below and state the hardware

categories to which they belong :


_________________ ________________________ _____________

____________________ _____________________ ____________________

59

4. Explain briefly about Operating Systems.

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

5. Name any two operating systems. ______________________

______________________

6. Which is the operating system on your computer?(Check with your

computer teacher) _____________________________


59

Switching on your Computer To switch your computer ‘ON’, make sure the power cable behind the

CPU is attached to the ‘Power Supply’ switch and power is ON.

Switch ‘ON’ the power button of your monitor.

Press the power button on the CPU once to switch your computer ‘ON’.

After a few moments the computer screen will appear as shown below.

This screen is called the ‘Login Screen’.


59

Username and Password

In the same way a computer recognizes every individual and his work by a user name. A User Name is a name used to gain access or entry into a Computer. Every student or a teacher is given a User Name.


How does your teacher identify you in the class?

He calls me by my name.

How do you safe guard your house when you are away?

59

Likewise if you do not want your computer to be opened by others you may keep it locked by giving a password. A password is a secret word or phrase known only to individuals or a small group of people.

A Password can be a combination of alphabets, numbers or both. comp123, Karnataka, 15081947, 12JUNE08 are some examples of passwords.

Once you type in your username and password, the computer opens up. You can now start working on your Computer.

Note: You may collect user name & password for you from the teacher.© Educomp Solutions Ltd.

We lock the house with a lock and key.

59

You will learn how to create them later.

Desktop and its Components

When you start your computer by entering your username and password, the screen that appears is referred to as the desktop - the desktop acts as your work area.

Let us look at the elements of a computer desktop more closely!


Activity:

1. Switch ON your computer, as explained above.2. Observe what happens on the screen when you switch it on.3. Note down approximately how much time it takes for the desktop to

appear, after computer is switched ON. Why is it? Check with your teacher.

Top panel

Bottom Panel

Icons

Application and Action Menu

Show Desktop

Volume ControlSystem Date & Time

59

Top Panel The top panel is located on the top edge of the desktop.

You can see a red hat? That is the Start button. You can click on it to begin almost any task on the computer.

The top panel also displays the system date and time. You will learn about changing the system date and time later.

Icons


59

Icon means ‘image’. Computer icons are small symbols on computer screen that represent computer files.

By ‘double–clicking’ on an icon, you can open the computer file it represents.

Start Button

How to

work on your Computer?

Everything that you do on a computer; it is done in FILES.

Just like you do your Math homework in your Math notebook and your Science project in your Science notebook; similarly you must have different files for everything you do on a computer.

Files can record data, such as text or numbers. It can be a letter, an application, an essay, or a drawing. Even a movie is present as a file on the Computer.

To work on a Computer you must:

1. Open a file. Just like you open your notebook.

2. Work in the file. For example, you could type or you could draw, depending on what type of program (software) you have opened. If you open a Drawing Program, you will be able to draw.


Activity:

1. Getting mouse friendly:

a) Move your mouse pointer to the ‘Start’ button.

b) Left click on the ‘Start’ button. A menu will appear.

c) Now, take the mouse pointer to ‘Games’ in the ‘Start Menu’.

Another sub – menu will appear.

d) List down the available games.

2. Drag and Drop

a) Take the mouse pointer to ‘Trash’ icon. Press the left mouse

button.

b) Now while keeping the left mouse button pressed. Pull the

‘Trash’ icon down.

c) Release the mouse button. Notice that the positions of the

icons have changed…..!

The ‘Start’ button helps you to access all the programs (software) that are there on your computer.

When you click on the ‘Start’ button, a list of all the programs (software) on your Computer will be displayed. This list is called a ‘Pop-up-Menu’ because of the way it suddenly pops out. A ‘Menu’ means a list of options you may choose from. Recollect menu card of a restaurant where all the available items are listed.

59

3. Save the file (store the file onto a storage device) Remember, if you do not save the data, before switching your computer OFF, you will lose it.

4. Close the file. Just like you close your notebook when you are done!

We will learn about each of these steps in the coming sections.

What is a Window?A WINDOW is a rectangular part of a computer screenscreen where we can carry out our work. that contains a display different from the rest of the screen.

A computer window is a visual work area through which the user interacts with computer programs or software. It usually has a rectangular shape

As explained earlier everything that you perform on your computer is done in files. An open file looks like a WINDOW on your desktop.

You will learn more about the structure of a window in the next section.© Educomp Solutions Ltd. Click the X

button to close a window.

59

Looking Inside Your ComputerWe know by now that we work in files on a Computer. We must also save the files on a storage device to avoid losing the information. When you save a file on your Computer, it is automatically saved on the Hard Disk of your Computer. The Hard Disk is called the ‘C Drive’.


59

Your Computer provides a way to show you where all your files are on your computer.

Can you see a Computer icon on your desktop?

If you double click on the Computer icon, a window appears. The left side of the window displays the important locations on your Computer, such as the C Drive, Desktop, Floppy Drive, and CD Drive. If you click on any of these, their content will appear in the right side of the window.

Can you see several smallall yellow boxes? These are called FOLDERS. Folders are like containers. Folders help us to store our files in an orderly manner.

Why do we use different containers to store different food items in the kitchen? It is easier to find the food items if they are stored in separate containers, isn’t it! Just imagine what would happen if you stored all your grains- rice, wheat and beans - in one container. You would take days to pick out a handful of rice from the container.

Just like you keep different containers for rice, wheat, beans, etc so that you find everything easily and quickly; similarly you can make different folders in your Computer to store different types of files. For example, you can make a folder called DRAWING, and store all your drawing files in that folder. You


59

can make another folder called ENGLISH and you can store all your essays and articles in that folder.

You can make as many folders as you want. Remember to name the folders properly so that you can find your files easily.

You can also create a folder inside a folder. For example, you can make a folder named SOCIAL SCIENCE. Inside this folder, you can make 3 more folders – HISTORY, CIVICS and GEOGRAPHY.

How to Create a Folder?

It’s easy. Right-click anywhere on the right side of the above window, point on ‘New’, and then click on ‘Folder’. At this point a new folder should appear in the window with the words "New Folder" highlighted. Type whatever you would like to name this folder and it will put what you type in place of the words "New Folder".


59

Shutting down your Computer Step 1: Close all the windows that are open in your computer.

Step 2: Click on the ‘Actions’ button. Then click on ‘Log out’. The

following screen will appear.

Step 3: Click on ‘Shut Down’ option to end your session.

Step 4: Then click on ‘OK’.

In a few seconds Windows will shut down. In some computers, the power switch on the computer is turned off automatically and the monitor goes dark. At this time you can turn off the power switch on the monitor.



Activity:

1. List out the parts of computer.

2. Switch on your computer and monitor.

3. Note the first screen on the monitor, after the computer is

switched on.

4. List out the icons you find on the desktop.

5. Move the mouse and see how the arrow moves around the

desktop.

6. Click on Home icon, a new window will open.

Note down the contents of the window.

On top right side of the window, you will find three buttons,

click on each of them and note what it does?

7. Right click on the Desktop, observe the menu commands.

8. Use single click on the icon on Desktop to select the icon.

9. Drag any icon on desktop and move it to different location.

59

Working with Keyboard Let us have some fun now!

1. Click the Start button.

2. Click on Accessories.

3. Click on Text Editor.

This will open up the GEDIT window. GEDIT helps you to create text documents. This is the GEDIT screen:


Work Area

Tool Bar

Menu Bar

Once you open ‘GEDIT’, you will get a blank screen with a small blinking vertical bar. This vertical bar is known as the ‘cursor’. It indicates where

the data you type will start appearing.

Click the X button to close a

window.

Title Bar

59

The GEDIT Screen Elements

Title Bar: The Title Bar displays the name of the file. Since it is a new file, there is no name assigned to it.

Menu Bar: The Menu bar consists of a number of items. When you click on each of the items, a list of commands (instructions) appears. These commands help you to create your text document.

Work Area: The Work Area is where you can type.

Tool Bar: The Tool Bar consists of common tools that help you to create your text document.


59

Alphabet Keys The alphabet A to Z (a to z) are typed using the Alphabet keys.

Number KeysThe Number keys are used to type numbers.


Number Keys

Alphabet Keys

59

Arrow Keys (Cursor Control Keys)The Arrow keys are used to move the cursor left, right, up and down.

Caps Lock Key The Caps Lock Key is present on the left side of your keyboard. When

pressed it changes all typed letters to capitals until it is pressed again.

Pressing this button will normally turn a light on in the button or

somewhere else on your keyboard to indicate that it is turned on.


Right arrow key : moves the cursor right by one space

Left arrow key : moves the cursor left by one space

Down arrow key : moves the cursor down by one line.

Up arrow key : moves the cursor up by one line.

59

Whilst Caps Lock is pressed, all letters will be typed in uppercase

(capitals).

Shift Key

The shift key works when used together with another key.

When you press and hold the Shift key and also type alphabetic keys:

If Caps Lock is off, capital letters are displayed on the screen. For

example if you press ‘Shift’+ ‘G’, then ‘G’ will be displayed on the

screen.

If Caps Lock is on, small alphabets are displayed on the screen. For

example if you press ‘Shift’ + ‘G’, then ‘g’ will be displayed on the

screen.

If you press the Shift key with number keys, special characters are displayed

on the screen. For example if you press ‘Shift’ + ‘2’ then ‘@’ will be

displayed on the screen.


Activity:What will be displayed on the screen if we press:

1. Shift + 4 = ______________

2. Shift + 5 = ______________

3. Shift + 7 = ______________

4. Shift + k = ______________ if Caps Lock key is OFF

5. Shift + p = ______________ if Caps Lock key is ON

59

Backspace Key

The Backspace key is used to remove the character to the left of the

cursor position. It also moves the cursor backward one character space. It

is useful for correcting typing mistakes.

Delete Key

The Delete key is used to remove characters and other objects. It

removes the character immediately to the right of the cursor or the

highlighted text or object.


Delete key deletes the character to the right of the cursor and

Backspace key deletes the character to the left

59

Spacebar Key This is the longest key on the keyboard. This key is used to give a space

between words or numbers. For example if you type ‘New’ and press the

Space bar and then type ‘Delhi’, then it will display ‘New Delhi’ on the

screen.


Activity:What will be displayed on the screen if we press the following keys :

1. n e i s h e a = _________________

2. a p i i l a = __________________

Activity:What will be displayed on the screen if we press the following keys:

d k r a o = _______

59

Enter Key

This is one of the most important key on the keyboard. It is also called

Return key. As you press this key, the cursor will come to the next line.

For example if you press the following keys:

The monitor will display the following:

‘My Name is

Gautam’

Control KeyThis key also works in combination with some other keys. When you

press the Control key along with another character, some special

function is performed. For example if you press ‘Ctrl’ and ‘N’ in gedit,

it will open a new document for you.

Alternative Key


59

This key is also similar to the Control key. When you press the Alternative key along with another character, some special function is performed. It is generally used to open different menu options in an application. For example if you press ‘Alt’ and ‘F’ in gedit, it will open File menu options for you.

Open Source Software

As we already know, software is a collection instructions that

can be understood by the Computer. These instructions are

first written in a human-readable format (referred to as

Source Code), and then converted to a format that

computers can understand.

Software for which the Source Code is freely available to the general public for use

and modification, is called Open Source Software. Open Office and Linux are

examples of Open Source software. Windows XP, Windows 2003, MS–Office are not

open source software.


Activity:

Press the following key combination in gedit and find out what happens:

1. Ctrl + P = _______________________________________________________

2. Alt + E = _______________________________________________________

3. Ctrl + O = _______________________________________________________

4. Alt + V = ________________________________________________________

59

Activity:

1. Explain briefly about Open Source Software.

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

2. Name any Open Source Software.

_____________________________________________________________________

3. Name some software which are not Open Source Software.


Open Source Software are freely available. Source code of the

programs are also available. This helps in modifying/improving the

programs.

Tell me how do you distinguish Open Source Software from the other

software?

59

_____________________________________________________________________

Maintenance of Computers

Do’s© Educomp Solutions Ltd.

A Computer is a delicate machine. If you do not handle it properly it may get damaged….!

Thank You Computer Jee. Please tell me what precautions are to

be taken while using a Computer.

59

1. Switch off the monitor, system unit and the printer before switching off the mains.

2. Before switching on the mains, ensure that the power switches in the system unit, monitor and printer are in the OFF position.

3. Remove CDs and floppy diskettes before switching off the computer.4. Use dust covers for the PC, monitor, keyboard, printer, etc., when not

used.5. Store CDs and floppy diskettes in cool and clean place.

Don’ts

1. Do not move your computer when it is running2. Do not plug in keyboards, mouse, printers, or other connections while

the computer is running.3. Do not hold the wires and pull while removing any cable or wire. Hold

the connectors and pull4. Do not exert great force on key switches. Handle them softly.5. Do not put any load on the diskette.6. Do not obstruct air circulation to the computer site.7. Do not use rough (hard) material for cleaning.8. Do not use pencil or ball point pen to label the diskettes; use soft

tipped felt pen.9. Do not bend or scratch the CD.


59

10. Do not allow eating or drinking near the PC.

Lesson Summary:

A Computer is machine which works on electricity.

A Computer cannot work on its own. It works as per our commands or

orders.

The parts of computer which we can touch physically are called ‘Hard-

ware’.© Educomp Solutions Ltd.

Let us revise…

59

Computer programs (instructions) that instruct the computer to do a

task are called ‘Software’.

ROM is Read Only Memory. It contains instructions for the computer to

function.

RAM Random Access Memory is the working memory of a computer.

The computer uses RAM to store data temporarily while working on it.

The data in RAM is lost when the computer is switched off.

Hard disks can store large amount of data. They can store data perma-

nently.

We have to maintain the computer properly to ensure its proper func-

tioning.

1. Write Yes or No against the following:

a. Computer is an electronic machine. _______________


Let’s put on our thinking caps now..

59

b. Machines make our work easier. __________

c. Monitor is an input device. ________________

d. You can write on Read Only Memory. ___________________

e. There are more than 3 buttons present on the mouse._______________

f. There are 14 functions keys present on the keyboard. ______________

g. Computer can remember a lot of things for a long time. ___________

h. Mouse is a pointing device. _________________

i. Printer gives us the soft copy of the document. __________________

j. CD-ROM can store more data than a Hard Disk. __________________

2. Put a tick mark ( ) against the correct option:

Device Machine Non –Machine


59

3. Name the following components of computer.


59

4. Categorize the following devices and write their name under correct heading.

a. Hard Diskb. Mousec. CD-ROMd. CPUe. Monitorf. Random Access Memory

S. No. Input Device Output Device Processing Device


59

5. Write the difference between the following :a. RAM and ROMb. Backspace and Delete Key

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

________________________________________________________________________

_____________________________________________________________________

6. Identify and colour the keys on the given keyboard to type a word ‘Computer’. Use different colours for different keys.

7. Write down the steps to Shut down the computer.____________________________________________________________________

____________________________________________________________________


59

____________________________________________________________________

____________________________________________________________________

____________________________________________________________________

____________________________________________________________________

____________________________________________________________________

8. Match the following :

Select an object, move the writing cursor, activate a button or link

Open an object (e.g. icon), Select a word

Opens the context menu -gives you a list of commands that changes depending on where you click


59

Select some writing, select multiple objects, copy or move something.

9. Fill in the blanks.

a. ________________ Key is used to type in uppercase letters (A to Z).

b. Computer System = _______________ + Software.c. _______________ allows us to write on the screen.d. Mouse is kept and moved on a __________________.e. There are __________ number of Function keys are present on

the keyboard.f. _____________ is called as the brain of the computer.g. ________________ Output device allows us to hear sound.h. _____________ are small images that represent the computer

files or folders.i. By pressing ___________ key you can move to next line.j. ______________ Keys are used to move cursor up, down, right

and left.

10. What are the things which we should not do in

the Computer Lab.

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________© Educomp Solutions Ltd.

59

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

___________________________________________________________________________

Group Activities:

11. Visit your Computer Lab. to study the following :

a. What is the brand of the computer? Check CPU and Monitor.

b. How big is monitor’s screen? Check the diagonal measurement.

c. Look at the mouse. Are they optical? Learn what is an optical mouse?


59

d. Try to increase and decrease the volume of the speaker.

e. What is the Hard Disk capacity (memory)? Check with your teacher.

f. How many keys are there on the keyboard? Count them.

g. Are there keyboards with different no. of keys? Check with your teacher.

h. Look at the printer. Whether printer accepts single sheet or double sheets? Check with your teacher. Are there different types of printers?

i. Ask your teacher to show you the Pen Drive and CDs. What are their memory capacities?

12. Read more on Computers; Discuss with your seniors to know more about computers; When you are visiting different places like Railway Station, Restaurant, Shops, Banks, look for Com-puters in use and learn more on computer and its uses.


Documents

Chapter - 1 - Weebly · Web viewFunction Keys: These are F1, F2….. F12. They perform special functions. You will learn about them later. MOUSE The computer mouse is called so because