9th Computer Notes

Chapter 2: Fundamentals of Operating System

Write short answers of the following questions.

i. Why operating system is important software for a computer? Give any five reasons.

Answer: The operating system is important software for a computer because

1. It controls the working of the computer system.
2. It acts as an interface between the user and the computer.
3. It facilitates program execution.
4. It helps in developing application programs.
5. It can be viewed as a resource manager.

ii. Give any three objectives of the operating system.

Answer: Following are three objectives of the operating system:

1. The main objectives of the operating system are convenience and efficiency.
2. It makes the computer more convenient to use.
3. It allows computer resources such as CPU, Memory, Input/output devices and internet to be used in an efficient manner.

iii. Mention few disadvantages of using DOS.

Ans:  Following are few disadvantages of using DOS:

1. User must know the syntax of the command.
2. DOS commands are difficult to remember.
3. It is a single user and single task operating system.
4. Its character base interface therefore cannot support graphics.
5. It cannot use easily as Graphics user interface.

iv. Name two operating systems which are used in modern mobile phones.

Ans: Popular Mobile Operating Systems:

• Android OS (Google Inc.)
• iOS OS / (Apple)
• Symbian OS (Nokia)

v. What difficulties a student may face if he/she is not familiar with the operating system of a computer?

Ans.

Without basic knowledge about the operating system, a computer is useless. Students may face difficulties in the steps involved in the installation of operating systems, office automation software and antivirus software in computers. Therefore a student must familiar with the operating system of a computer.

vi. Define UNIX and Windows operating systems.

Ans:

UNIX Operating System:

UNIX is a multi-user CLI operating system introduced in 1969. It allows multiple users to run different programs at the same time. UNIX was developed for use on a large computer system (Mainframe). It uses a command line interface but later Graphical User Interface was also introduced.

Windows Operating System:

Windows is the most popular operating system used on microcomputers. It was developed by Microsoft. Many different versions of the Windows operating system were developed and used successfully in the past. Some of these versions are Windows 98, Windows XP, Windows 7, 8 and 10.

vii. Differentiate between single-user and multi-user operating systems.

Ans:

Single-user Operating System	Multi-user Operating System
1. Operating system that is used by a single user at a time is known as single user operating system.	1. Operating system that allows many users to use a computer at the same time is known is multi-user operating system.
2. It allows a single user to login and use the computer at a time.	2. It allows many users to login to a single big computer and run different programs at the same time.
3. It is used on microcomputers	3. It is used on minicomputers and mainframes..
4. It requires less memory and costs less.	4. It requires a powerful CPU, large memory and large hard drives.
5. Some examples of single-user operating systems are DOS, Windows 95, Windows XP, Windows 7, etc.	5. Windows NT, UNIX and Linux are popular multi-user operating systems.

viii. What is meant by managing data and why is it Important?

Ans: Managing data:

Managing data means storing files in secondary storage devices such as hard disk or USB flash drive in an organized way. This helps in finding files easily and quickly. Files are stored in folders. The Document folder in Windows is the default folder where the user saves files.

It is important because it provides facilities to quickly and easily create folders and copy or move files into them. It also allows the user to delete files and folders that are not needed any more.

ix. What is meant by resources of computer?

Ans. Resource of computer:

The resources of a computer include microprocessor, memory and all the devices attached to the computer. Operating system allocates resources of a computer to the application program according to the user’s requirement in an efficient way to improve the performance of the computer.

x. What types of problems may a student face if no antivirus is installed in his/her computer system?

Ans. Computer virus will damage data, software, or the computer itself. A computer virus is a program that literally infects other programs and databases upon contact.

Some of the activities that a virus has been programmed to do are:

• Copy themselves to other programs.
• Display information on the screen.
• Destroy data files.
• Erase an entire hard disk.
• Lie dormant for a specified time or until a given condition is met.

Write long answers of the following questions.

i. Explain the main functions of the operating system.

Ans. The following are the main functions of the operating system:

• Process Management
• Memory Management
• Input/Output Management
• File Management
• Resource Management
• User Management

Process Management:

Process management is an essential part of an operating system (OS). A process is a program in execution. In a computer system, multiple processes are executing concurrently or waiting for their turn to be executed. A process in execution needs resources like processing resources, memory and I/O resources.

Memory Management:

Memory management is the process of allocating memory space for user programs in main memory. When programs are run by users, the operating system allocates portions of free memory to programs.

Input/output Management:

It is the process of controlling the operation of all the input/output devices attached to the computer. The user communicates with the computer through various input/output devices such as a keyboard, mouse, monitor printer, etc.

File Management:

The file management system is part of the operating system that organizes stores and keeps track of computer files and folders. Computer files can be documents, programs, images, videos, etc.

Resource Management:

The operating system automatically manages the resources of a computer when application programs are executed by the computer user. The resources of a computer include a microprocessor, memory and all the devices attached to the computer.

User Management:

User management is an important feature of the operating system for maintaining a secure computer system. The operating system gives full control over a computer system to a person known as the administrator. An administrator installs various programs on the computer system for users. He also creates and manages user accounts. When a user account is created, the user is assigned a username and a password. Administrator allows the users to run various application programs that are installed on the computer.

ii. Describe the following computer interfaces.

a)Command Line Interface

b)Graphical User Interface

c)Menu-driven Interface

Ans: a) Command Line Interface:

In CLI, commands are given to a computer with a keyboard. It is based on textual input. The user types in a command and presses the Enter key to execute it. Two commonly used operating systems that use CLI are DOS and UNIX. CLI is difficult to use because users have to remember the commands to perform any task

b) Graphical User Interface:

GUI is a graphical interface for computer users to interact with computer. It uses windows, icons, menus and pointer. Window is a rectangular portion of monitor in which information is displayed. Icon is a graphical symbol that represents a file, folder, program, device, etc.

c) Menu-driven Interface:

Menu driven interface presents a menu on the screen, user makes a choice and then the next menu appears. The user makes another choice and so on. Menu driven interface is easy to use as compared to CLI. The user reads the options and makes his choices. Menus contain the commands to use the operating system. Menu driven interface is also used in some application programs and other devices such as mobile phone and iPod.

iii. Describe the following types of operating systems.

a)Batch Processing System

b)Time-sharing System

c)Real-time System

Ans: a) Batch Processing System:

In a batch processing system, jobs are grouped in batches and the computer executes them one by one. When the current job terminates, the computer automatically loads the next job and starts executing it. Batch processing operating systems greatly improved the use of computer systems.

Batch processing systems are suitable for tasks where large amount of data has to be collected and processed on a regular basis.

b) Time-sharing System:

A timesharing system is a feature of an operating system in which multiple users can run different programs on a large-scale computer. It allows many users to have access to a computer at the same time and share the computer’s time. In a timesharing system, the central processing unit is switched rapidly between the programs so that all the user programs are executed simultaneously.

c) Real-time System:

Real time operating systems must process information and produce a response within a specified time. These operating systems are developed for special applications.

These are used to control industrial processes such as oil refining. Real time operating systems are used to supply immediate response within limited time. For example, a measurement from an oil refinery indicating that temperatures are getting too high might demand quick response to avert an explosion.

There are a number of real-time operating systems used in military and space research programs.

iv.Write notes on Macintosh and Linux operating systems.

Ans: Macintosh Operating System:

Mac OS is a series of operating systems developed by Apple Incorporation for their Macintosh computers. It was introduced in 1984 with the original Macintosh computer and has GUI.

The latest version is Mac OS X. It is a UNIX based user-friendly operating system. There are some specialized versions of Mac OS X used on devices such as iPhone, iPod, iPad and new Apple TV.

Linux Operating System:

Linux is free open-source operating system introduced by Linus Torvalds in 1991. It is faster but difficult to use as compared to Macintosh and Windows operating systems. It is not a popular operating system. Linus Torvalds started the development of Linux operating system and laid its foundation. Millions of programmers around the world work on Linux to improve it.

Its source code is freely available on Internet Programmers can view, edit and publish an improved version.

v. Describe the basic icons of Windows operating system.

Ans: Basic icons of Windows operating system:

An icon is a small graphical symbol that represents a file folder, application or device. There are some special system icons such as Recycle Bin and Computer that are kept on the desktop. Icon has a label at the bottom describing its name.

Recycle Bin:

It is a temporary place (folder) for items that the user deletes from disk. When a file or folder is deleted from a hard disk it goes to the Recycle Bin. The user can restore it to its original location. User can also delete a file or folder permanently from the Recycle Bin.

Computer Icon

Computer icon allows the user to access the contents of computer drives and manage files and folders. When user double-clicks on Computer icon, it will open a window that displays the drives present in the computer. It is used to navigate and manage the computer resources.

Folder Icon:

Folder icon resembles a physical file folder. It is used to store files. A folder can have another folder inside it which is known as subfolder. Folders are used to keep files in an organized manner on a storage device such as hard disk so that they can be accessed easily.

File Icon:

In a GUI, files are also represented by icons. A file may contain text, image, music or video. Users recognize a file by its icon.

Program Icon:

Executable program files are also represented by icons. Different graphical symbols are used for different program icons.

Shortcut Icon:

Shortcut icons are created to access a program, file or folder quickly. They have an arrow at the bottom left corner and the name below it.

 

Select the best answer for the following MCQs.

i.Which interface is based on textual input?

A. GUl 

B. CLI

C. Menu-driven interface 

D. Windows

ii. Which of the following interface uses window, icon, menu and pointer to interact with computer

A. GUI

B. CLI

C. Menu-driven interface 

D. DOS

iii. Which of the following operating system was introduced in 1969?

A. Macintosh 

B. Linux

C. UNIX 

D. DOS

iv. Which of the following operating system response within a specified time?

A. Batch Processing System 

B. Time-sharing System

C. Multiprogramming System 

D. Real-time System

v. Which of the following is open source operating system?

A. UNIX 

B. Linux

C. DOS 

D. Novell’e Netware

vi. Which of the following user interface is the easiest one to learn and use?

A. CLI 

B. GUI

C. Menu driven interface 

D. DOS

vii. Which of the following operating system allows many users to use a computer at the same time?

A. Sing-user operating system

B. Batch processing system

C. Real-time processing system             

D. Multi-user operating system

viii. In which of the following operating system, CPU is switched rapidly between all the programs to simultaneously execute all of them?

A. Batch Processing System                         

B. Time-sharing System

C. Real-time System 

D. DOS

ix. Which of the following Windows icon allows user to access a program, file or folder quickly?

A. Program icon 

B. Computer icon

C. Shortcut icon                                                       

D. Recycle Bin icon

x. Which of the following Windows icon allows user to access the contents of computer Program icon drives and manage files and folders?

A. Program icon 

B. Computer icon

C. Shortcut icon 

D. Recycle Bin icon

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Chapter 3 Office Automation