Introduction
Inside the computer there is one program that manages all the other programs, just like a boss in an office. This program is called Windows which is the most popular operating system that controls the working of the computer. In order to start and work, every computer needs an operating system. An operating system acts like an interpreter between the computer hardware and the user. An interpreter is required because the computer and human beings speak different languages. Windows can come in different versions (such as Windows 95, Windows 98, Windows 2000 and Higher versions). Windows is a wonderful program because you can do many things with it ? play games, listen to music and paint at the same time. Let's learn how to work with Windows. You don't have to do anything special to start Windows. When you switch on the computer. Windows will start automatically.
What is Operating System (OS)
OS means operating system of a computer. The operating system is the most important software on your computer as it controls and coordinates all the activities of a computer. It is the operating system that supports all the software on a computer. Operating system is a set of commands and programs in combination which serves two purposes. Firstly, it helps us to interact with the computer. Secondly, it helps the hardware and the software resources to communicate with each other. Basically, an OS forms a link between the three: User, Hardware and Software. It is also known as system software. It helps in operating the system in all aspects.
Window XP, Microsoft Window, Mac OS X, UNIX, Linux, etc. are the examples of operating system. Microsoft windows is a family of proprietary operating system most commonly used on personal computers. When you first switch on your machine, the Windows operating system loads and the first screen which appears is called the Desktop. Desktop refers to the main background area, It is like your personal work area. Actually you get a feel of what is inside your computer. Several icons or small pictures are located on the left side of the Desktop. You can use your Desktop for many tasks such as opening programs, copying files, connecting to the Internet and so on. You may have used the Paint icon in your computer lab for drawing pictures. It is very easy to work with Windows because it uses a GUI (Graphical User Interface) and offers graphical icons and visual indicators instead of text and ou need not have to remember any commands.
Icons are small graphical images that can represent your computer's programs, files, folders and printers. You also see a Taskbar, a grey bar, usually at the bottom of the Desktop. The Taskbar gives the current status of the screen. The Desktop got its name because it looks like an office desk, with a number of tools and other objects that you can use in your work. At one end of the Taskbar you have the Start button which is very important. The other end has the System Tray, which usually has the clock display and pictures or icons that represent some services that might be running in the background. When you open a program, a rectangular window opens up against the background of the Desktop. One can open several such windows, one upon the other. Each window is associated with an application. That is why the program is called 'Windows'. Many windows can be kept open at the same time while you work with one of them. To work with the Windows software, the first step more... 
Social and Ethical Behaviour
Just as it is not proper to read the letters of others and use their things without permission, accessing the personal information of others on the computer also violates ethical principles. Computer Ethics is a set of moral principles that govern an individual or a group on what is acceptable behaviours while using a computer.
Some of the rules that the students should follow while using computers are the following:
Waugh does not know anything about the computer ethics. He asks Hamilton about computer ethics. Hamilton has given him a list of computer ethics. Read the list given below and identify which is/ are correct?
1. Do not use computers to steal other's information.
2. Do not access files without the permission of the owner.
3. Do not copy copyrighted software without the author's permission.
4. Always respect copyright laws and policies.
(A) 2 and 3
(B) 1, 2 and 4
(C) 1 and 3
(D) All of these
(E) None of these
Answer: (B)
Explanation
Correct Option:
(B) Statements 1, 2 and 3 are correct about computer ethics. Therefore, option (B) is correct.
Incorrect Options:
(A) Statement 2 is correct but statement 3 is incorrect. Therefore, option (A) is incorrect.
(C) Statement 1 is correct but statement 3 is incorrect. Therefore, option (A) is incorrect.
(D) All the given statements are not correct. Therefore, option (D) is incorrect.
(E) All the given statements are not incorrect. Therefore, option (E) is incorrect.
Fill in the blanks:
1. _______ is a set of moral principles that govern an individual or a group on what is acceptable behavior while using a computer.
2. ________ is a broad philosophical concept that goes beyond simple right and wrong and looks towards 'the good life'.
3. Delete your______________ more... 
Introduction
Computers and software are a part of our life, both at home and in school. The use of computers for long hours is a major issue of computer-related health risks which include repetitive stress injuries, eyestrain, obesity, back problems, etc. Correct postures pay off in later life and will help to minimize potential problems. Computers can also cause social isolation and in some cases long-term damage to physical, emotional or intellectual development and this requires a right moral behavior about which we will discuss later in this chapter.
Correct Postures While Using Computers
Effective Ergonomics (The science concerned with designing safe and comfortable machines for humans.) can keep our bodies healthy and pain-free when using the computer for a long period of time. Correct postures play a large role hence we should follow the good habits when we use the computer.
Do's and Don'ts
Some of the computer's Do's and Don'ts are the following:
Gordon explaining Richard: What is the right posture of sitting while using computer. Which of the following explanations about right posture are correct?
1. You should sit up bend in front of the computer. Improper sitting may result in back ache and eye sight problems.
2. Make sure that your fingers are relaxed while typing and using a mouse.
3. Open the legs of the keyboard to give it a slight slope and use it comfortably.
(A) 1 and 2
(B) 2 and 3
(C) Only more... 
Data Measurement System
Suppose you are asked where you live or the name of your friends, you will reply immediately because you remember them and this information is already in your memory. A computer also has a memory which stores a lot of information inside: it. A computer stores everything in its CPU.
All the data that enters into the computers first converts into the binary number system. One digit in binary number system is called bit and combination of eight bits is called byte. Bit is the smallest measuring unit of computer memory. It means binary digits. Just like we use kilograms and grams to measure weight, the computer's memory is organized as a collection of bytes. A byte is the basic unit that is used to represent the alphabetic, numeric and alphanumeric data. Byte is a unit of measurement of computer memory. Each number, alphabet or special character takes place of one byte. For example, the name Zacob needs 5 bytes for its storage. Large amounts of memory are indicated in terms of kilobytes (1,024 bytes), megabytes (1,048,576 bytes) and gigabytes (1,073,741,824 bytes).
Units to measure memory are given in the following table:
Bit = 0 or 1
Nibble = 4 Bits
1 Byte (B) = 8 Bits
1 Kilobyte (KB) = 1024 B
1 Megabyte = 1024 KB
1 Gigabyte = 1024 MB
Match the following:
A B
1. Bits i. 4 bits
2. Bytes ii. binary digit
3. Nibble iii. 8 bits
(A) 1, i; 2, ii; 3, iii
(B) 1, ii; 2, iii; 3, i
(C) 1, iii; 2, ii; 3, i
(D) 1, ii; 2, i; 3, iii
(E) 1, i; 2, iii; 3, ii
Answer: (b)
Explanation
Correct Option:
(B) Option (B) is matched correctly.
Incorrect Options:
(A) Option (A) is matched incorrectly.
(C) Option (C) is matched incorrectly.
(D) Option (D) more... 
What is Directory?
Directories are like the drawers of a table. Files are like the actual things that we keep in the drawers. A directory is also known as a folder. A folder is used to put similar files together. For example, files containing drawings can be put into the Drawing folder; files containing text can be put into the Text folder. Different types of folders are made so that various types of files can be stored in them in an organized manner. We can create folders within a folder. These are called sub- folders. Therefore, a directory allows you to group your files in a meaningful way. A directory is a logical area on the hard disk or floppy disk where files are kept. Each directory is used to keep one type of file.
For example, if we keep files Three - A, Three - B and Three - C in one directory and name it Class-Three, then we can say that directory Class - Three has the names of all the students of the three different sections of Class- III. In Windows, a folder is symbolized by icon:
Few statements are given below about directories. Select the correct statements.
1. A directory is used to put similar files together.
2. You can create folders within a folder.
3. A directory is also known as a bundle.
4. A directory is an illogical area on the hard disk.
(A) 1 and 2
(B) 3 and 4
(C) 1, 2 and 3
(D) All of these
(E) None of these
Answer: (A)
Explanation
Correct Option:
(A) Statements 1 and 2 are correct about directory. Therefore, option (A) is correct.
Incorrect Options:
(B) Statements 3 and 4 are incorrect. Therefore, option (B) is incorrect.
(C) Statements 1 and 2 are correct but statement 3 is incorrect. Therefore, option (C) is incorrect.
(D) All the given statements are not correct. Therefore, option (D) is incorrect.
(E) All the given statements are not incorrect. Therefore, option (E) is incorrect.
Fill in the blanks with proper word:
1. ______are like the drawers of a table.
2. Each _______ is used to keep one type of file.
3. A directory is also known as a ______
(A) Selves, directory and bundle
(B) Directories, file and folder
(C) Directories, directory and folder
(D) File, filename and folder
(E) Rack, folder and file
Answer: (c)
Explanation
Correct Option:
(C) Options given in (C) are correct. Therefore, option (C) is correct.
Incorrect Options:
(A) Options given in (A) are incorrect. Therefore, option (A) is incorrect.
(B) Options given in (B) are incorrect. Therefore, option (B) is incorrect.
(D) Options more... 
What is a File?
Imagine that you have only one notebook for doing homework and class work for all subjects. If you wish to study English notes, you will have to check the whole notebook page-by-page to find what you need. But if you make separate notebooks for class work and homework and separate notebooks for different subjects this job will become very easy. All work that we do on a computer is stored on it in the form of files. A computer file is a block of information or a resource for storing information. Computer files can be compared to paper documents which are traditionally kept in offices and libraries. Each file has a file name and can have anything including a drawing, text, picture, etc. in it. In modern computer systems, files are typically accessed using names (filenames). Just as our name has 2 parts - a first name and a surname, a filename also has two parts. The first part is called a filename and the second part is called a file extension. It is separated from the main name by a dot (.) Paint file icons have extension .bmp, text files have extension .txt, PowerPoint files have extension .ppt and documents have extension .doc Files on a computer can be created, moved, modified and deleted. We cannot get back or restore a file, once we delete it from the Recycle Bin. (See Figure 3.6.2) A file is the actual space taken by the data on the disk. Information in a computer file can consist of smaller packets of information (often called 'records' or 'lines'). When you save any work done on the computer, it occupies some memory of the computer. The amount of memory used by a file is called the file size. For example, if you want to store the names of the students of section A of Class Three, you can keep them in a file and name it Three - A. If you want to store the names of the students of section B of Class Three, you can keep them in a file and name it Three - B. In the same way, you can make Three - C and so on and these all files will take some space from the memory. You can keep different types of information in different files. (See Figure 3.6.3)
In Windows, a file is symbolized by the following icon:
Match the following files with their extensions.
A B
1. Paint file i. more... 
Introduction
Suppose you have only one room in your house, it would be inconvenient to study, work, cook, sleep, eat and relax, all in the same place. It will be very difficult for you to trace the things which you want and work peacefully. However, a house Ms divided into different rooms such as living room, dining room and study loom, etc. with each room containing the required things so that it is comfortable for you to live there. (See figure 3.6.1) "The same concept applies to data storage in computers as well. Just as a house contains many things like people, furniture, pets, etc, a computer also contains different types of information such as text, drawings, programs, games, etc. In a computer, we use the files and directories to keep our information in a safe and logical manner.
Input /Output Devices
In computing Input / Output or I/O refers to the communication between an information processing system (such as a computer) and the outside world. Inputs are the signals or data sent to the system and outputs are the signals or data sent by the system to the outside. Input/ Output devices are hardware devices that accept inputted information and also have the capability of outputting that information. Good examples of an Input/ Output device are a floppy diskette drive, CD-ROM and DVD-ROM units and a hard while some devices are considered only Input or Output devices, the typical devices for communication between computers are considered to be both Input and Output. For instance, the modem lets you connect to another computer, while allowing you to send and receive data and information at the same time. Another typical example is the network card that basically does the same thing in a small network. These kinds of devices are termed as bidirectional. Let's learn about some I/O devices in detail.
Floppy Disk
A floppy disk is a data storage medium that is composed of a disk of thin, flexible, magnetic storage medium encased in a square or rectangular plastic shell. Floppy disks are read and written by a floppy disk drive or FDD. They were invented by the American information technology company IBM. Floppy disks come in different sizes - in 8-inch (203 mm), 5+1D 4 in (133 mm) and 3+1D 2 in (89 mm) formats. For nearly three decades from the mid-1970s to the late 1990s, floppy disks were a popular form of data storage and exchange. While floppy disk drives still have some limited uses, they have now been replaced by USB flash drives, external hard disk drives, CDs, DVDs and memory cards.
CD-ROM
You must have seen or used CDs for matching movies, playing games and listening to music. CD-ROM is an acronym of "Compact Disc Read-Only Memory". It is a type of optical disk capable of storing large amounts of data ? up to 1GB, although the most common size is 650MB (Megabytes). A single CD-ROM has the storage capacity of 700 floppy disks and enough memory to store about 300,000 text pages. It is a pre-pressed compact disc for data storage and music playback. CD-ROMs are stamped by the vendor and once stamped; they cannot be erased and filled with new data. To read a CD, you need a CD-ROM player. CD-ROMs are particularly well-suited for information that requires large storage capacity. This includes large software applications that support colour, graphics, sound and especially video. CD-ROMs are popularly used to distribute computer software, including games and multimedia applications, though any data can be stored (up to the more... 
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