Computer Science Practical Book

Unit 2: FUNDAMENTALS OF OPERATING SYSTEM

Table of Content

2.1 Introduction

2.2 Operating System

2.3 Getting started with GUI O.S.

2.4 System Installation

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2.1 Introductioni) Know the objectives of Operating System. (O.S.)ii) Get familiar with the functions of O.S.

• Memory Management• I/O Management• Files Management• Resource Management• Users Management

iii) Differentiate between common types of O.S.• Command Line Interface (CLI)

- DOS- Unix

• Menu Driven Interface (Novel , DOS)• Graphical User Interface (GUI)

- Macintosh- Linux- Windows

2.2 Operating Systemi) Classify Operating System

• Single user O.S.• Multi users O.S.

ii) Describe the following types of O.S.• Batch processing• Time sharing processing• Real time processing

2.3 Getting started with GUI O.S.i) Identify the basic icons of GUI O.S.ii) Manage data (Files / folders)

2.4 System Installationi) Install Operating Systemii) Install Office Automation Softwareiii) Install Antivirus

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2.1 IntroductionAn operating system is a program that acts as an interface between the user and the computer hardware and controls the execution of all kinds of programs.All computers rely on an Operating System (OS) to provide the interface for interaction between users, applications, and hardware. The OS boots the computer and manages the file on the system.

2.1 i) Know the objectives of Operating System. (O.S.)Operating system is an important part of almost every computer system. The basic objective of an operating system is to share the hardware among a number of hardware components, programs and users. It manages and allocates computer resources efficiently, reliably and unobtrusively.

The main objectives of Operating systems are:Booting the computerThe process of starting or restarting the computer is known as booting. A cold boot is when you turn on a computer that has been turned off completely. A warm boot is the process of using the operating system to restart the computer.Performs basic computer checking tasksThe operating system performs basic computer chekcing tasks, such as managing the various peripheral devices such as the mouse, keyboard and printers. For example, most operating systems now are plug and play which means a device such as a printer will

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automatically be detected and configured without any user intervention.Provides a user interfaceA user interacts with software through the user interface. The operating system is responsible for providing a consistent user interface. Manages system resourcesThe operating system also manages system resources such as the computer's memory and sharing of the central processing unit (CPU). The operating system ensures that each application gets the necessary resources it needs in order to maximise the functionality of the overall system.File managementThe operating system also provide file management system. It allows the user to perform such tasks as creating files and directories, renaming files, coping and moving files, and deleting files.

2.1(ii) Get familiar with the functions of O.S.All operating systems perform the basic functions such as controlling hardware access, managing files and folders, providing a user interface, and managing applications. An OS provides services for following functions: Memory management: The memory management component of an operating system is concerned with the organisation and management of system memory.

Memory management keeps track of each and every memory location either it is allocated to some process or it is free. It checks how much memory is to be allocated to processes. It decides which process will

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get memory at what time. It tracks whenever some memory gets freed or unallocated and correspondingly it updates the status. I/O managementUsers interact with computers by providing data to computers through I/O devices. One of the main functions of an operating system is to control access to the input and output devices attached to the system’s mainboard. Operating system must respond to user keystrokes and mouse clicks, interpret I/O requests from user applications and decide when two or more processes require the services of a device at the same time.

Operating System manages the communication between user and device drivers. Following are the major activities of an operating system with respect to I/O Operation. I/O operation means read or write operation with any file or any

specific I/O device. Program may require any I/O device while running. Operating system provides the access to the required I/O device

when required. Files managementMost computer systems employ secondary storage devices (magnetic disk, magnetic tape, optical media, flash drives etc.) to provide non-volatile storage for programs and data. The operating system is responsible for allocating space for files on secondary storage media as and when required.

Resource management

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NOTE:A device driver is a small program that resides in memory and does nothing until called upon by the operating system. Its sole purpose is to relay instructions and data between the operating system and a specific hardware device.


The four main resources of the computer system are: . 1. Memory: For memory – An operating system coordinate, control

and manages these resources. For memory operating system effectively and efficiently use and allocate required memory demands of the programs. It means that there should not be any idle memory and a waiting program at the same time.

2. CPU: For CPU – operating system allocates to the CPU time to the processes waiting for it so as to minimize its idle time, increase system’s efficiency and meet job’s deadline if any.

3. Input/output devices: For I/O devices – proper device management that is, allocation of I/O channel and device to a job asking for it, in minimum wait time and ensure user free environment.

4. Programs / Data: For PROGRAMS and DATA – Operating systems take care of proper storage for the programs and data in the computer system. Operating system also ensures the protection and unauthorized use of programs and data.

In case of multi-user or multi-tasking environment, resources such as main memory, CPU cycles and files storage are to be allocated to each user or job. Following are the major activities of an operating system with respect to resource management.

OS manages all kind of resources using schedulers. CPU scheduling algorithms are used for better utilization of CPU.

Users managementAn operating system acts as an interface between the user and the computer hardware and controls the execution of all kinds of programs. The operating system is responsible for allowing user the right of access to the resources and programs of the computer system. It defines the rules relating to execution of programmes by guaranteeing that the resources are used only by programmes and users with the relevent authorizations. Operating system does the following activities related to users:

OS provides user an interface to interact with system. OS managers input devices to take inputs from the user. For

example, keyboard. OS manages output devices to show outputs to the user. For

example, Monitor. OS Response time needs to be short since the user submits and

waits for the result.

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User accounts are the method by which an individual is identified and authenticated to the system. User accounts have several different components to them. First, there is the username. The password is next, followed by the access control information. You can configure and customize each user account based on the needs of the individual who will be using it. For example, desktop settings, screen savers, shortcuts, and user-specific data files are all stored separately for each account. In general, give each user of a system his/her own account.

2.1(iii) Differentiate between common types of O.S.We can differentiate between the different types of operating system on the basis of:

i. User Interface: User interface is used to interact with the computer to perform various tasks. User gives commands to computer and enters the data into computer. These are examples of user interfacing. The operating system plays the main role for interfacing between user and computer. Thus, we can classify the operating system on the basis of what type of user interface it has.

i. Command-line interface (CLI): The user types commands at a prompt.

ii. Graphical user interface (GUI): The user interacts with menus and icons.

ii. Number of user: It means how many users can be connected to a computer at one time. An operating system can be classified as a single user or a multi-user operating system.

i. Single user: Only one user can work with the programs and use the peripheral devices.

ii. Multi user: Two or more users can work with programs and share peripheral devices such as printers, at the same time.

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iii. Processing: An operating system can be classified on the basis of its capacity to support and utilize one or more computer processor. Examples of operating systems that would fall into this category are:

i. Single Processor: The computer can have only one CPU that programs use.

ii. Multiprocessor: The computer can have two or more central processing units (CPU) that programs share.

iv. Tasking: It means the capability of an operating system to handle number of applications at one time.

i. Single tasking: Only one applications can be run by the operating system.

ii. Multitasking: The computer is capable of operating multiple applications at the same time.

Command Line Interface (CLI)A CLI (command line interface) is a user interface in which a user responds to a visual prompt by typing in a command on a specified line, receives a response back from the system, and then enters another command, and so forth.A command line interface (CLI) relies solely on textual input and output. It shows only characters (and no images), and input is performed with a keyboard. Because a command line interface requires unique commands, this interface is often more difficult to learn because of the need to memorize dozens of different commands.

The biggest advantage of the CLI is its flexibility. That is, it can be used to easily do things that are difficult to do. For example, CLI programs often provide many options thereby providing greater flexibility of use. Also, multiple CLI commands can be combined using pipes to perform multiple tasks. The operating systems using CLI are DOS and UNIX.1. DOS: DOS (Disk Operating System) was the first widely-installed

operating system for IBM-compatible computers. The first personal computer version of DOS, called PC-DOS, was developed for IBM by Bill Gates and his new Microsoft Corporation. He retained the rights

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to market a Microsoft version, called MS-DOS. PC-DOS and MS-DOS are almost identical and most users have referred to either of them as just "DOS." DOS uses a command line, or text-based interface, that allows the user to type commands. By typing simple instructions such as pwd (print working directory) and cd (change directory), the user can browse the files on the hard drive, open files, and run programs. While the commands are simple to type, the user must know the basic commands in order to use DOS effectively. This made the operating system difficult for novices to use.

2. The UNIX is referred to a stable, multi-user, multi-tasking operating system for servers, desktops and laptops. It was developed in the 1970s at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and others. Unix is primarily a command line operating system with additional applications. There are many different versions of UNIX, although they share common similarities. The most popular varieties of UNIX are Sun Solaris, GNU/Linux, and MacOS X.

Menu Driven Interface (Novel , DOS)Menu-driven interface lists menu choices that a user can select to execute a command. Menu driven interface only shows menus with specific options for the user to select.

The main advantage of menu-driven systems is that they are easy to use. The main disadvantage of menu-driven systems is getting to one

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particular option can often involve working through many different menu screens. Graphical User Interface (GUI)It is a user interface that includes graphical elements, such as windows, icons and buttons. The term was created in the 1970s to distinguish graphical interfaces from text-based ones, such as command line interfaces. However, today nearly all digital interfaces are GUIs. Features of GUIs include:

• They are much easier to use for beginners.• They enable you to easily exchange information between

software using cut and paste or 'drag and drop'. • They use a lot of memory and processing power. It can be

slower to use than a command-line interface if you are an expert user.

• They can be irritating to experienced users when simple tasks require a number of operations.

Today, most users prefer the graphical user interface (GUI) offered by Windows, Mac OS (Macintosh), Linux and others. Typically, most of today's UNIX-based systems offer both a command line interface and a graphical user interface.Macintosh Linux

WindowsA GUI (pronounced gooey) is also known as a WIMP interface because it makes use of:• Windows - a rectangular area on the screen where the commonly

used applications run • Icons - Small pictures that represent commands, files, or windows. • Menus - a list of options from which the user can choose what they

require • Pointers - a symbol such as an arrow which moves around the

screen as you move your mouse. Helps you to select objects.

In addition to their visual components, graphical user interfaces also make it easier to move data from one application to another. 2.2 Operating Systemi) Classify Operating System

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We can classify the operating system on the basis how many user can connects and use resource of the computer at the same time. Single user O.S.A single-user operating system is a type of operating system (OS) that is developed and intended for use on a computer or similar machine that will only have a single user at any given time. This is the most common type of OS used on a home computer, as well as on computers in offices and other work environments. Single user operating systems can be split into two types:

o single user, single application operating systemso single user, multi tasking operating systems

Single user, single application: This type of operating system only has to deal with one person at a time, running one user application at a time. An example of this kind of operating system would be found on a mobile phone. There can only be one user using the mobile and that person is only using one of its applications at a time.Multi users O.S.: You will find this kind of operating system on a personal computer. The operating system is designed mainly with a single user in mind, but it can deal with many applications running at the same time. For example, you might be writing an essay, while searching the internet, downloading a video file and also listening to a piece of music. Example operating systems are

•Windows •Linux•Mac OS X

The difference compared to the Single-Use, Single Application operating system is that it must now handle many different applications all running at the same time.The memory available is also very different, for example it is quite normal to have Gigabytes of RAM available on a personal computer which is what allows so many applications to run.ii) Describe the following types of O.S. Batch processingBatch processing is a technique in which Operating System collects one programs and data together in a batch before processing starts. In batch procession OS keeps number tasks in memory. Tasks are processed in the order of submission i.e. first come first served fashion. When a task completes its execution, its memory is released and the output for the task gets copied into an output spool for later printing or processing.

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Advantages• Batch processing takes much of the work of the operator to the

computer.• Increased performance as a new job get started as soon as the

previous job finished without any manual intervention.Disadvantages• Difficult to debug program.• A job could enter an infinite loop. • Due to lack of protection scheme, one batch job can affect pending

jobs.

• Time sharing processingTime sharing is a technique which enables many people, located at various terminals, to use a particular computer system at the same time. In time-sharing processor's time is shared among multiple users simultaneously. Operating system uses CPU scheduling and multiprogramming technique to provide each user with a small portion of a time. Thus, the user receives an immediate response.

Advantages of Timesharing operating systems are following: • Provide advantage of quick response.• Avoids duplication of software.• Reduces CPU idle time.

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http://ecomputernotes.com/images/Time-Sharing-System-Active-State-of-User-5.jpg


Disadvantages of Timesharing operating systems are following.• Problem of reliability.• Question of security and integrity of user programs and data.• Problem of data communication.• Real time processingReal time system is defined as a data processing system in which the time interval to process and response time is very small. Real-time systems are used as a control device in a dedicated application. For example Scientific experiments, medical imaging systems, industrial control systems, weapon systems, robots, and home-appliance controllers, Air traffic control system etc. 2.3 Getting started with GUI O.S.i) Identify the basic icons of GUI O.S.Getting started with GUIIn graphical user inter face Desktop is the area on the display screen where different element of GUI are present. These elements are intended to represent real objects on a real desktop. A Graphical User Interface (GUI) presents a number of graphical elements to the user to interact with the program. Typical GUI components include windows, menus, buttons and text areas.

We will consider Microsoft Windows 7 operating system to discuss the basic icons and elements of GUI operating system.

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The basic elements of Windows 7 are: DesktopWhen your computer starts for the first time, what you see is called the Desktop. It will look something like this: The Desktop is the space where all your programmes appears when you start them up. This space contains a default background wallpaper, but it can also contain shortcuts to programmes, documents and folder. You can change the default background wallpaperStart Button Arguably, the most important part of the Taskbar is the Start button. The Start button is where a lot of the action takes place in Windows 7. The Start button can be found in the bottom left of your screen, and looks like this:

Click the Start button once with your left mouse button and you'll see a menu appear:

Start Menu The Start menu is the primary interface used to launch applications and administrative or configuration utilities. The Start menu is split into two different areas. The white area on the left represents recently used applications as well as pinned items that may be placed permanently on the Start menu. The blue area is for specialized links to important areas of the computer system, including Control Panel, Devices and Printers, and special storage areas for user

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data. The All Programs link is used to access all installed Windows applications through a branching menu structure.

We have four recently opened documents that we can click on. These will then open in Word. Notice the small pin icon to the right of the Recent list. Clicking the icon will pin that document to the Word shortcut menu. This is useful if you open one particular document all the time.TaskbarThe Desktop is split into two areas. The strip at the bottom, with the clock to the right and the round Start button to the left, is called the Taskbar. The taskbar is the thin strip that runs across the bottom of your screen. It is split into a number of different areas: a round Start button, Quick Launch icons, a notification area, and a clock. All other areas are the Taskbar itself. The image below shows where the different areas are: The taskbar is used to both launch applications and manage them once running in the newer versions of Windows.

The Start button is the most important area of the Taskbar. There is one more area on the Taskbar, and it's easily overlooked - the Show Desktop button. In the images above, you can just see a narrow rectangle to the right of the clock: Click this button to minimize all open programmes and reveal the desktop.Notification Area

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The Notification area, formally called the System Tray, is the area of the Taskbar where you can view programmes and tasks that are running in the background, as well as view important messages about updating your computer. In the image below, the Notification area shows three icons:

The first one, the white arrow, is for hidden icons. Click the white arrow

to see which icons have been hidden.

Date and Time in Windows 7 The default clock shows you the date as well as the time:

Icons and Shortcuts The Windows Desktop can contain both icons and shortcuts. The icons link to system components such as Computer, the Control Panel, or the Recycle Bin. The shortcuts link to applications, folders, or documents the user wishes to access quickly. Many application installation processes will ask your permission to place a shortcut on the Desktop for the application being installed. The shortcuts are noticeably different from system icons because they have a blue arrow in the lower-left corner.Recycle Bin The Windows Recycle Bin is not really part of the Desktop; however, unless you customize the installation process with an answer file, the Recycle Bin is the only icon on the Desktop after installation completes. The Recycle Bin exists on each internal hard drive within a Windows computer. It is a hidden folder into which files are copied when they are deleted. The copy of the files may be restored at a later time. When space is need on the hard drive, the files that have been in the Recycle Bin for the longest time are deleted first

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to make room for new data. You can empty the Recycle Bin by right-clicking it and selecting Empty Recycle Bin.

ii) Manage data (Files / folders)File: The programs, the user data or information, are held in discrete units in computer storage are called files. Almost all programs, data or information stored in a computer must be in a file. Folder: In graphical user interfaces such as Windows and the Macintosh environment, a folder is an object that can contain and organized multiple documents. A folder can be retrieved, moved, and manipulated as one entity. In the DOS and UNIX operating systems, folders are called directories.

The operating system handles the organisation and management of files and folders (directories) saved on a computer disk. The file management system allows the user to perform such tasks as creating files and directories, renaming files, coping and moving files, and deleting files.

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Windows explorer is a file management system in Windows 7 operating system. It shows the files and folder in a hierarchical way. Using Windows explorer you can perform actions like cut, copy, paste, rename or deleted on the files and folders. 2.4 System Installationi) Install Operating SystemNow we will learn to install Windows 7. This installation takes 15 to 30 minutes, depending on the speed of your machine.Step#1 Turn ON your PC and Press ‘F2’ Continuously. There will come up and option to boot through CD/DVD. Select that option. Windows will start loading its files. Step#2 Now you will get the Windows Setup Window. This is the part to select Language for your windows. Select ‘English’ and click Next. Also there will be a ‘INSTALL NOW’ button. Click on it and proceed to next step.

After a few moments, you will reach the installation menu. Your first step is to choose the language and the keyboard.You will be now taken to the Install now menu. We have already prepared for the installation, so you can click Install now and proceed.

Step#3 There will be a license agreement. Check on ‘I ACCEPT’ and proceed to NEXT. After that there will be an option to install windows. ‘UPGRADE’ and ‘CUSTOM’. Right now we are installing a clean version so Click on CUSTOM.Step#4 In this step you will do partitioning of your drive. Be careful, this is the most important part of the Installation. In this you will

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allocate spaces to your drive. If you want to create a new drive, simply click on a drive and then click ‘NEW’. A new drive will be created.

Step#5 When you have created the drives, Simply Select the drive in which you want to install windows. Click ‘Format’, this will erase all the previous data on you that drive. Click on ‘NEXT’ to proceed.Step#6 Now you windows will start installing its files. Grab a cup of coffee and wait for a few minutes while it install. During this process don’t plug in or off your device. It might cause interruption and you might loose your data and have to begin the process all over again.

Step#7 Now when you files are installed. Your PC will be rebooted and now you will see is a ‘User Settings’ Screen. Simply add your Name and password and proceed to ‘NEXT’Step#8 In this step you have to activate your windows. Simply look at the back of your Windows CD/DVD cover there will be a PRODUCT KEY. Add this key into your PC and Click ‘NEXT’.

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Step#9 Now you have Installed you windows. Give the desired information the Windows Step guide will ask, like Time Zone, Update Timing and Your Computers location. There are three types of location. ‘WORK’, ‘PUBLIC’ and ‘HOME’. Select on anyone of the them according to your location. It only add sharing security according to your location.Last Step – Congratulations:- You have installed you windows. Now you can see is your desktop. It is simple to use, setup your desktop and enjoy!

ii) Install Office Automation Software1. Before start to install Office 2007, write down the product key shown on the top of the CD in a paper.2. Insert the Microsoft Office 2007 Installation CD/DVD into your computer CD/DVD-ROM drive. After a few seconds, the Office 2007 setup screen will appear.3. You will be first prompted for the Office 2007 Product Key. Type in the 25-character product key correctly (Hyphens are added automatically). Click the Continue button.

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4. The next screen displays the Microsoft Software License Terms. Read it and click the checkbox by "I accept the terms of this agreement." Then click on the Continue button. 5. The next screen displays the installation options for Office 2007. You have two options to choose: Install Now and Customize. Click "Install Now" button.

6. This will install Microsoft Office 2007 Enterprise. During the installation process, a progress bar is display showing that Office 2007 is currently being installed on your computer and it takes some time to complete.7. The next screen will show that Office 2007 is successfully installed. You will have the option to "Go to Office Online" or just "Close" the screen.

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8. Just click the Close button to complete the installation.iii) Install AntivirusMicrosoft makes an antivirus program that is available for free for all Windows users. You can have it downloaded and installed in just a matter of minutes. 1. Visit the Security Essentials website located at

http://www.microsoft.com/Security_Essentials/

2. Click the blue Download Now button. You should see a graphic similar to the one below.

3. After this you will be prompted to Run, Save, or Cancel. For this installation, we’ll choose Run.

4. A user Account Control (UAC) window pop up, click Yes.

You will see the Installation Wizard’s welcome message. This provides a link to the Privacy Statement, and notes that it will need to check for updates after installed. Keep your internet connection live and to validate your copy of Windows during the installation.

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http://www.microsoft.com/Security_Essentials/


Click on I accept to continue with the installation, or I decline if you do not want to continue. Next, validate your installation of Windows 7. This is a required step, if you pass validation, you will be taken to the next step of the installation.

Once you have passed the Validation Check (WGA, Windows Genuine Advantage,) a blue check mark with the text This copy of Windows passed genuine validation appears you will be immediately redirected to the first step of the install process.

A progress bar like the one below appears. This may take a while so have patience.

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Once Microsoft Security Essentials is installed it will immediately update itself with the latest antivirus definitions.This is an important step, as new variations of viruses and malware are released into the wild on a daily basis. No matter which antivirus software you choose to use, always keep it up to date.

Next, you should see the main page of Microsoft Security Essentials, which is now running on your system.

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Exercise 2Tick ( )the Correct option1. What is operating system?

a. Collection of programs that manages hardware resourcesb. System service provider to the application programsc. Link to interface the hardware and application programsd. All of the mentioned

2. Which one of the following error will be handle by the operating system?a. Power failureb. Lack of paper in printerc. Connection failure in the networkd. All of the mentioned

3. A Microsoft Windows is a(n)a. Operating systemb. Graphic programc. Word Processingd. Database program

4. Which of the following is an example of a real time operating system?a. Lynxb. MS DOSc. Windows XPd. Process Control

5. Which of the following operating system does not implement the multitasking truly?a. Windows 98b. Windows NTc. Windows XPd. MS DOS

6. Main difference between DOS and windows operating system?a. windows is big b. Windows multitasking environment c. windows graphical user interface d. windows work very fast

7. What program runs first after computer is booted and loading GUI?a. Desktop Managerb. File Managerc. Windows Explorerd. Authentication

8. Which of the following does not support more than one program at a time?a. DOSb. Linux

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c. Windowsd. Unix

9. Which of the following is not an operating system?a. DOSb. Linuxc. Windowsd. Oracle

10. Which of the following is not a multitasking operating system?a. Windowsb. Linuxc. Win NTd. DOS

11. A named location on a disk where files are stored is called a. Folderb. RAMc. ROMd. Motherboard

12. A user-interface that is easy to use is considered to bea. User-happyb. User-simplec. User-friendlyd. Multiuser

13. In Windows, start button is used toa. Run applicationsb. Device settingc. Turn off the systemd. All of above

14. Combination of characters that allows access to a computer a. Password b. Gadget c. Window explorer d. Icon

15. What action allows you to open user account and makes the computer available?a. Password b. Start menu c. User interface d. Logging on

16. Which one of the following Operating Systems(OS) has command line as the user interface?a. DOS b. Linux c. UNIX d. Mac OS

Answer the following questions:

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1. What is the purpose of operating system?2. What are the major activities of an operating system with regard to

i. process managementii. memory managementiii. I/O managementiv. Files managementv. Resource management vi. Users management

3. Differentiate between i. CLIii. Menu Driven interfaceiii. GUI

4. Classify the operating system on the basis of the following:i. Single User and Multiuserii. Batch Processing and Time sharing processingiii. Batch Processing and Real Time processing

5. List the basic element of Window 7 and describe their functions.

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