5

Operating System: Windows XP

1. What do you mean by an operating system? What are its objectives?

Ans.: An operating system (OS) is a collection of system programs that together controls the operation of a computer system. The OS along with hardware, application and other system software, and users constitute a computer system. It is the most important part of any computer system. It acts as an intermediary between a user and the computer hardware. The OS has the following two objectives:

1. Managing hardware: The OS manages and controls various hardware resources of a computer system. These hardware resources include processor, memory, disk space, I/O devices, etc. The OS supervises which input device's data are requesting for being processed and which processed data are ready to be displayed on the output device. In addition to communicating with the hardware, it provides an error handling procedure and displays an error notification. If a device is not functioning properly, it tries to communicate with the device again. If it is still unable to communicate with the device, it provides an error message notifying the user about the problem. Figure 5.1 illustrates how the OS manages the hardware resources of a computer system.

   

   Figure 5.1 Managing Hardware

2. Providing an interface: The OS organizes applications so that users can easily access, use, and store them. When an application is opened, the OS assists the application to provide the major part of the user interface. It provides a stable and consistent way for applications to deal with the hardware without the user having to know all the details of the hardware. If the application program is not functioning properly, the OS again takes control, stops the application, and displays an appropriate error message. Figure 5.2 shows the layered structure of a computer system.

   

   Figure 5.2 Layered Structure of a Computer

2. Discuss the different types of OS.

Ans.: The OS has evolved immensely from its primitive days to the present digital era. From batch processing systems to the latest embedded systems, the OS can be classified into the following six broad categories:

1. Batch-processing OS: This type of OS was one of the first to evolve. It allowed only one program to run at a time. These kinds of OS can still be found on some mainframe computers running batches of jobs. It works on a series of programs that are held in a queue. The OS is responsible for scheduling the jobs according to priority and the resources required. These are good at churning through large numbers of repetitive jobs on large computers. For example, this OS would be best suited for a company wishing to automate their payrolls. A list of employees will be entered, their monthly salaries will be calculated, and corresponding pay slips would be printed. Batch processing is useful for this purpose since these procedures are to be repeated for every employee and each month.
2. Multi-user or time-sharing OS: This system is used in computer networks that allow different users to access the same data and application programs on the same network. It builds a user database account, which defines the rights that users can have on a particular resource of the system.
3. Multiprogramming or multitasking OS: In this system, more than one process can be executed concurrently. The processor is switched rapidly between the processes. Hence, a user can have more than one process running at a time. For example, a user on his computer can have a word processor and an audio CD player running at the same time. It allows the user to switch between the running applications and even transfer data between them. That is, a user can copy a picture from an Internet opened in the browser application and paste it into an image editing application.
4. Real-time OS: This system is designed to respond to an event within a predetermined time. This kind of OS is primarily used in process control, telecommunications, etc. The OS monitors various inputs that affect the execution of processes, changing the computer's model of the environment, thus affecting the output, within a guaranteed time period (usually less than 1 second). As this OS responds quickly, they are often used in applications such as flight reservation system, railway reservation system, and military applications.
5. Multiprocessor OS: This system can incorporate more than one processor dedicated to the running processes. This technique of using more than one processor is often called parallel processing. The main advantage of this OS is that it increases the system throughput by getting more work done in less time.
6. Embedded OS: It refers to the OS that is self-contained in the device and resident in ROM. Since embedded systems are usually not general-purpose systems, they are lighter or less resource intensive as compared to general-purpose OS. Most of these OS also offer real-time OS qualities. Typical systems that use embedded OS are household appliances, car management systems, traffic control systems, and energy management systems.

3. Discuss the main functions of an OS.

Ans.: An OS is the main aspect of a device, and is very important to its overall function. Without it, the computer will not be able to work. Thus, the main functions of the OS are as follows:

	Process management: As a process manager, the OS handles the creation and deletion of processes, the suspension and resumption of processes, and the scheduling and synchronization of processes.
	Memory management: As a memory manager, the OS handles the allocation and de-allocation of memory space as required by various programs.
	File management: The OS is responsible for the creation and deletion of files and directories. It also takes care of other file-related activities such as organizing, storing, retrieving, naming, and protecting files.
	Device management: The OS provides input/output sub-system between process and device driver. It handles device caches, buffers, and interrupts. It also detects device failures and notifies the same to the user.
	Security management: The OS protects system resources and information against destruction and unauthorized use.
	User interface: The OS provides the interface between the user and the hardware. The user interface is the layer that actually interacts with the computer operator. The interface consists of a set of commands or menus through which a user communicates with a program.

4. Discuss the process of booting of a computer?

Ans.: Booting is the process of loading the OS into the main memory. As the machine is switched on, the control is transferred to the bootstrap procedure of BIOS (basic input/output system). The BIOS comprises a set of several routines and start-up instructions inside a ROM, which is a non-erasable memory. This procedure inspects the computer to determine what hardware is fitted and then conducts simple test (power-on self test) for normal functionality. If all the tests are passed, the ROM then determines the drive to boot the machine.

5. What is a process? Discuss its various states.

Ans.: A process (also called job) is an execution of a sequence of instructions or program by the CPU. It can also be referred as the basic unit of a program that the OS deals with the help of the processor. It is initiated by the program to perform an action, which can be controlled by the user or the OS. In order to accomplish a task, it needs certain resources like CPU time, memory allocation, and I/O devices. It changes various states during its lifetime where each state indicates the current activity of the process. These states are as follows:

	New: A process is being created.
	Ready: A process is ready to be assigned to the processor.
	Running: A process is being executed.
	Waiting: A process is waiting for signal from some other process.
	Terminated: A process has finished its execution.

6. Diagrammatically, explain the life cycle of a process.

Ans.: To keep track of all the processes, the OS maintains a table known as the process table. This table stores many pieces of information associated with a specific process, that is, program counter, allocated resources, process state, CPU-scheduling information, etc. Initially, a process is in the new state. When it becomes ready for the execution and needs the CPU, it switches to the ready state. Once the CPU is allocated to the process, it switches to the running state. From the running state, the process goes back to the ready state if an interrupt occurs or to the waiting state if the process needs some I/O operation. In case the process has switched to ready state, it again comes to the running state after the interrupt has been handled. On the other hand, if the process has switched to the waiting state, then after the completion of I/O operation, it switches to the ready state and then to the running state. Thus, a process continues to switch among the ready, running, and waiting states during its execution. Finally, it switches to the terminated state after completing its execution. Figure 5.3 illustrates the life cycle of a process.

Figure 5.3 Life Cycle of a Process

7. Define thread and multithread programming.

Ans.: A thread is a task that runs concurrently with other tasks within the same process. Also known as lightweight process, it is the simplest unit of a process. The single thread of control allows the process to perform only one task at a time. An example of a single thread in a process is a text editor where a user can either edit the text or perform any other task like printing the document. In a multitasking OS, a process may contain several threads, all running at the same time inside the same process. It means that one thread of a process can be editing the text, while another is printing the document. Generally, when a thread finishes performing a task, it is suspended or destroyed.

Writing a program where a process creates multiple threads is called multithread programming. It is the ability by which an OS is able to run different parts of the same program simultaneously. It offers better utilization of processor and other system resources. For example, the word processor makes use of multithreading, that is, it can check spelling in the foreground as well as save document in the background.

8. Write a short note on process scheduling.

Ans.: In a multiprogrammed system, at any given time, several processes will be competing for the CPU's time. Thus, a choice has to be made which process to allocate the CPU next. This procedure of determining the next process to be executed on the CPU is called process scheduling and the module of OS that makes this decision is called scheduler. The prime objective of scheduling is to switch the CPU among processes so frequently that users can interact with each program while it is running. For scheduling purposes, there exist different queues in the system: job queue, ready queue, and device queue. As the processes enter the system for execution, they are kept into job queue (or input queue) on a mass storage device such as hard disk. From the job queue, the processes that are ready for the execution are brought into the main memory. In the main memory, these processes are kept into ready queue. In other words, the ready queue contains all those processes that are waiting for the CPU. For each I/O device attached to the system, a separate device queue is maintained. The process that needs to perform I/O during its execution is kept into the queue of that specific I/O device and waits there until it is served by the device.

9. Differentiate between the following:

(a) Uni-programming and multiprogramming

(b) Preemptive and non-preemptive scheduling

Ans.: (a) As the name implies, uni-programming means only one program at a time in which users can perform only one activity at a time. On the other hand, in multiprogramming, multiple programs can reside in the main memory at the same time and these programs can be executed concurrently thereby requiring the system resources to be shared among them. So, an OS must ensure that all processes get a fair share of the CPU time.

(b) In preemptive scheme, CPU scheduling takes place under the following two conditions:

1. When a process switches from the running state to the ready state
2. When a process switches from the waiting state to the ready state

   Here, the scheduler can forcibly remove the processor from the currently running process before its completion in order to allow some other process to run.

   On the other hand, in non-preemptive scheme, CPU scheduling takes place under the following two conditions:

1. When a process switches from the running state to the waiting state
2. When a process terminates

   Here, once the processor is allocated to a process, it cannot be taken back until the process voluntarily releases it (in case the process has to wait for I/O or some other event) or the process terminates.

   Thus, the main difference between the two schemes is that in preemptive scheme, the OS has the control over the process current states whereas in case of non-preemptive scheme, the process once entered into the running state gets the full control of the processor.

10. Write in brief on any two scheduling algorithms.

Ans.: The scheduler uses some scheduling procedure to carry out the selection of a process for execution. Two popular scheduling procedures implemented by different OS are first-come-first-served and round robin.

First-come First-served (FCFS)

In this, the processes are executed in the order of their arrival in the ready queue, which means the process that enters the ready queue first, gets the CPU first. To implement FCFS scheduling procedure, the ready queue is managed as a FIFO (First-in First-out) queue. Each time, the process at the start of queue is dispatched to the processor and all other processes move up one slot in the queue as shown in Figure 5.4. When new processes arrive, they are put at the end of the queue. FCFS falls under non-preemptive scheduling and its main drawback is that a process may take a very long time to complete, and thus holds up other waiting processes in the queue.

Figure 5.4 First-come First-served Procedure

Round Robin (RR)

It was designed keeping in mind the limitations of the FCFS scheduling procedure. This procedure falls under preemptive scheduling in which a process is selected for execution from the ready queue in the FIFO sequence. However, the process is executed only for a fixed period known as time slicing or quantum period after which it will be interrupted and returned to the end of the ready queue (Figure 5.5). In RR procedure, processes are allocated the CPU time on a turn basis.

Figure 5.5 Round Robin Procedure

11. What is a deadlock? When does this situation arise? What are the two schemes that ensure that deadlock never occurs?

Ans.: In a multiprogramming environment, several processes may compete for a limited number of resources. A process requests for the required resource and if it is not available then the process enters in the waiting state and remains in that state until it acquires the resource. There might be a situation when the process has to wait endlessly because the requested resource may be held by other waiting process. This type of situation is known as deadlock. A deadlock situation arises if the following four conditions hold simultaneously on the system:

1. Mutual exclusion: Only one process can use a resource at a time. If another process requests for the resource, the requesting process has to wait until the requested resource is released.
2. Hold and wait: In this situation, a process might be holding some resources while waiting for additional resource, which is currently being held by other process.
3. No preemption: Resources cannot be preemptive, that is, resources cannot be forcibly removed from a process. A resource can only be released voluntarily by the holding process, after that process has completed its task.
4. Circular wait: This situation may arise when a set of processes waiting for the allocation of resources held by other processes forms a circular chain in which each process is waiting for the resource held by its successor process in the chain.

The two schemes that ensure that deadlock never occurs are as follows:

1. Deadlock prevention: The system should ensure that at least one of the four deadlock causing conditions would not hold true so that deadlock can be prevented.
2. Deadlock avoidance: Additional information concerning which resources a process will require and use during its lifetime should be provided to the OS beforehand. For example, in a system with one CD drive and a printer, process P might request first for the CD drive and later for the printer, before releasing both resources. On the other hand, process Q might request first for the printer and the CD drive later. With this knowledge in advance, the OS will never allow the allocation of a resource to a process if it leads to a deadlock thereby avoiding the deadlock.

12. What are the different strategies used in allocating space to processes?

Ans.: In addition to managing processes, the OS also manages the primary memory of the computer. The part of the OS that handles this job is called the memory manager. The main challenge of efficiently managing the memory comes when a system has multiple processes running at the same time. In such a case, the memory manager can allocate a portion of the primary memory to each process for its own use. However, the memory manager must keep track of the running processes along with the memory locations occupied by them, and must also determine how to allocate and de-allocate available memory when new processes are created and old processes have finished their execution, respectively. The three different strategies used in allocating space to processes are as follows:

1. Best fit: The memory manager places a process in the smallest block of unallocated memory in which it will fit. For example, a process requests 12 KB of memory and the memory manager currently has a list of unallocated blocks of 6, 14, 19, 11, and 13 KB blocks. The best fit strategy will allocate 12 KB of the 13 KB block to the process.
2. First fit: The memory manager places the process in the first unallocated block that is large enough to accommodate the process. Using the same example to fulfil 12 KB request, the first fit will allocate 12 KB of the 14 KB block to the process.
3. Worst fit: The memory manager places a process in the largest block of unallocated memory available. To furnish the 12 KB request again, the worst fit will allocate 12 KB of the 19 KB block to the process, leaving a 7 KB block for future use.

Figure 5.6 illustrates that in best fit and first fit strategies, the allocation of memory results in the creation of a tiny fragment of unallocated memory. Since the amount of memory left is small, no new processes can be loaded here. This job of splitting primary memory into segments as the memory is allocated and de-allocated to the process is known as fragmentation. The worst fit strategy attempts to reduce the problem of fragmentation by allocating the largest fragments to the new processes. Thus, a larger amount of space in the form of tiny fragments is left unused. To overcome this problem, the concept of paging was used.

Figure 5.6 Strategies for Memory Allocation

13. Discuss the following:

(a) Paging

(b) Virtual memory

Ans.: (a) Paging: It is a memory management scheme that allows the processes to be stored non-contiguously in the memory. The memory is divided into fixed size chunks called page frames. The OS breaks the program's address space into fixed size chunks called pages, which are of same size as that of page frames. Each address generated by the CPU (i.e., logical address) is divided into two parts: a page number (high-order bits) and a page offset or displacement (low-order bits). Since the logical address is a power of 2, the page size is always chosen as a power of 2 so that the logical address can be converted easily into page number and page offset. To map the logical addresses to physical addresses in the memory, a mapping table called page table is used. The OS maintains a page table for each process to keep track of which page frame is allocated to which page. It stores the frame number allocated to each page and the page number is used as index to the page table. Figure 5.7 shows the logical memory, page table and physical memory. The main advantage of paging is that it minimizes the problem of fragmentation since the memory allocated is always in fixed units and any free frame can be allocated to a process.

Figure 5.7 Logical Memory, Page Table, and Physical Memory

To map a given logical address to the corresponding physical address, the system first extracts the page number and the offset. The system, in addition, also checks whether the page reference is valid (i.e., it exists within the logical address space of the process). If the page reference is valid, the system uses the page number to find the corresponding page frame number in the page table. That page frame number is attached to the high-order end of the page offset to form the physical address in the memory. The mechanism of translation of logical address into physical address is shown in Figure 5.8.

Figure 5.8 Address Translation in Paging

(b) Virtual memory: It is a way of showing the main memory of a computer system to appear effectively larger than it really is. Normally, a process executes only in the main memory, which is limited in size. But, some of the graphic-oriented applications like 3D video games; business applications, etc. require large memory for running such applications than the main memory. It is not essential that the whole program must be loaded in the main memory for processing as only the currently referenced page needs to be present in the memory at the time of execution. Therefore, the rest pages of the program can reside in a hard disk portion allocated as virtual memory and can be loaded into the main memory whenever needed. This process of swapping the pages from the virtual memory to the main memory is called page-in or swap-in. With the virtual memory, the system can run programs that are actually larger than the primary memory of the system. It allows for very effective multiprogramming and relieves the user from the unnecessarily tight constraints of the main memory.

14. Define buffer.

Ans.: A buffer is a temporary storage area that takes a stream of bits from a device like keyboard to a serial communication port. It holds the bits and then releases them to the CPU at a convenient rate so that the CPU can act on it. This task is important when a number of processes are running and taking up the processor's time. The OS instructs the buffer to continue taking the input from the device. In addition, it also instructs the buffer to stop sending data back to the CPU if the process, using the input, is suspended. When the process, requiring input, is made active once again, the OS will command the buffer to send data again. This process allows a keyboard to deal with external users at a higher speed.

15. What do you mean by spooling?

Ans.: Spooling refers to storing jobs in a buffer so that the CPU can be efficiently utilized. It is useful because devices access data at different rates. The buffer provides a waiting station where data can rest while the slower device catches up. The most common spooling application is print spooling. In print spooling, documents are loaded into a buffer, and then the printer pulls them off from the buffer at its own rate. Meanwhile, a user can perform other operations on the computer while the printing takes place in the background. Spooling also lets a user place a number of print jobs on a queue instead of waiting for each one to finish before specifying the next one. The OS manages all requests to read or write data from hard disk through spooling.

16. Write in brief on the following terms:

(a) CLI

(b) GUI

Ans.: (a) CLI: It stands for command line interface. It is an interface provided by the OS that facilitates the user to enter commands via an interactive terminal. This interface was used in early days of computing where commands were only means to initiate programs, applications, etc. To use CLI, a user had to learn many commands for proper operation of the system.

(b) GUI: It stands for graphical user interface. It is an interface that provides user with pictures rather than just characters to interact with the machine. It displays icons, buttons, dialog boxes, etc. on the screen. The user sends instructions by moving a pointer on the screen (generally mouse) and selecting certain objects by pressing buttons on the mouse while the mouse pointer is pointing at them.

17. List examples of some popular OS.

Ans.: Some examples of popular or multi-user OS are UNIX, Linux, MS-DOS, Microsoft Windows (Windows 95, Windows 98, Windows 2000, Windows XP, and Windows 2007), Microsoft Windows NT.

18. What are the main differences between MS-DOS and Windows OS?

Ans.: Both MS-DOS and Windows are OS, but still they have got some differences among them. These differences are listed in Table 5.1.

Table 5.1 Differences Between MS-DOS and Windows OS

19. What are the features of Windows OS?

Ans.: Windows OS is developed by Microsoft to overcome the limitations of MS-DOS OS. The main features of Microsoft Windows OS are as follows:

	The interface used in Windows OS is GUI. So, it is more convenient for a new user to learn and work on it.
	File naming can contain up to 255 characters as well as some punctuation marks, such as commas and semi-colons.
	It has built-in communications and networking features so that a system can act as a network client or server.
	User can run more than one program at a time, thus, it is a multi-user OS. This means that a user at the same time can have a word processor and an audio CD player running on his computer.
	It provides a rich set of system administration and software development tools.
	It serves as a complete operating environment for users. It has a standard way of working, that is, Microsoft Windows word processor works in a similar way as any other type of Windows program does.

20. Discuss some features of Windows XP.

Ans.: Windows XP is an OS introduced in 2001 by Microsoft and is a part of the Windows family of OS. Along with a redesigned look and feel to the user interface, this new OS uses a more stable and reliable environment than previous versions of Windows. It provides a new interface that uses graphics to simplify navigation and to complete common tasks, thus, making learning and working easier. Microsoft released Windows XP in two versions: Windows XP Home and Windows XP Professional. Windows XP Home edition is designed for home use and small businesses, while Windows XP Professional is specifically designed for advanced home computing, businesses, and larger organizations. Windows XP provides a new interface to simplify navigation and perform common tasks (like creating and opening of a file) easily. The various features that make Windows XP a powerful, fast, efficient, and stable OS are as follows:

	Improved interface: It provides a completely redesigned interface Start menu that lets one access programs more quickly. Also, it keeps a record of programs and files one uses more often. In addition, it displays the most used items in the Start menu while it hides the least used items.
	More reliable: It is based on the same technology that is used in Microsoft Windows NT and Windows 2000. This makes Windows XP much more stable than Windows 95, Windows 98, and Windows ME and greatly reduces the number of system crashes and system restarts.
	Better file and folder management: It makes it easier to view and work with files and folders. For example, Thumbnail view lets one to preview photos and images and the new File and Folder tasks pane lets one to easily copy, move, rename, or delete any file or folder.
	Better help and support: It provides efficient help and support with new features such as Remote Assistance that allows one to contact computer experts and lets them fix a problem on the computer even if they are miles apart geographically.
	More secure: It provides new security tools that help keep the computer more secure and provide new technologies that run in the background, making the computer run more efficiently. This OS includes the new Security Center that allows one to check the status of the important security elements on the computer—Windows firewall, automatic updates, and virus protection software—making it convenient for one to understand how to keep the computer better protected against viruses and other security threats.
	Remote desktop: It includes a feature known as Remote Desktop that allows one to access the Windows session from another computer just as if one was in front of the computer. For example, one can connect to the office computer from home, have access to all of the files and network resources as though one was in front of the computer at office. One can leave programs running at work, and when one get home, one can see the desktop at work displayed on the home computer with the same programs running.
	ClearType: It provides a special feature called ClearType that makes the words on the computer screen look as smooth as the words on a page. This increases the font resolution of the words written in different programs like Notepad and WordPad.

21. List some of the Start menu items along with their functions.

Ans.: The Start menu provides a way to open most of the software applications that are installed on the computer. It has been customized to provide quick access methods to all the programs and Windows utilities present on the computer. Some of the most commonly used Start menu items with their descriptions are listed in Table 5.2.

Table 5.2 Start Menu Items

22. What do you know about desktop, icon, file, folders, and shortcuts?

Ans.:

Desktop

It is the first screen visible after logging in Windows XP OS. When Microsoft Windows XP is opened, the desktop appears. It is a full-screen display where all Windows activity takes place. It is part of a GUI, where icons, menus, and dialog boxes on the screen represent programs, files, and options on a user computer. It is actually an invisible folder called desktop folder and the user can move files and folders to the desktop for easy access. In addition, it allows users to run programs and use a file system without using the command prompt of the OS.

Icon

It can be thought of as symbols that represent a program, shortcut to a program, or a folder. When one use Windows XP for the first time, the desktop contains only recycle bin. To display required icons, the user should follow some steps. They are listed as follows:

1. Right-click anywhere on the desktop and select Properties from the shortcut menu. This displays the Display Properties dialog box.
2. Select the Desktop tab and click the Customize Desktop button.
3. In the Desktop icons pane of the General tab, select the desired icons and click OK twice.

File

It is defined as an organized and structured collection of related information stored in a secondary storage device. The information can be of different types such as text, data, or images.

Folders

They provide a very convenient and useful method of storing files and subfolders in an organized way on a computer's hard drive or on a removable drive. For example, a folder could be created on the hard drive to keep all business correspondence with a particular customer. This folder can also contain files other than documents for that customer. One can also create folders inside a folder. For example, if one has a folder named Sports, then inside it other folders such as Cricket, Football, and Hockey can also be created for holding various files in these folders. Here Cricket, Football, and Hockey are called subfolders.

Shortcuts

These are the icons that can be created for commonly used applications on the desktop. To create shortcut, right-click the desired file or folder and select Send To from the shortcut menu. This displays another pop-up menu, from where select Desktop (create shortcut) option.

23. List the icons that appear by default on the desktop.

Ans.: The desktop includes icons, each having a specific function. Desktop icons can be thought of as symbols that represent a program, shortcut to a program, or a folder. When one use Windows XP for the first time, the desktop contains only recycle bin. The rest of the icons usually found on other Windows OS are not seen on the desktop. The main icons that appear by default on the desktop are listed in Table 5.3.

Table 5.3 Icons on the Desktop

 

Icons	Name	Description
	My Computer	It displays documents and files. It also provides access to hard drives and removable drives of the computer (both local and network).
	My Network Places	It enables one to communicate with network resources on the network for file-sharing purpose.
	My Documents	It is used to store documents. It also contains data files, which can be easily organized.
	Recycle Bin	It is a temporary storage area used for storing deleted file and recover files accidentally deleted from the hard drive or floppy drive.
	Internet Explorer	It provides access to Internet.

 

24. Define screen saver. How can one set the screen saver of Windows?

Ans.: A screen saver is an inbuilt utility that appears on the user screen when the mouse or keyboard has not been used for a specified period. It is primarily used to prevent damage to the phosphor element present in the monitor. The screen saver tab allows one to specify the screen saver and its settings (Figure 5.9). In this tab, one can also use the Power option, which allows one to change the power settings of the monitor. It provides options to save power when the computer is not in use. This is especially useful when the computer is used for a longer duration, for example, whole day, or when some background operation is going on (like transferring of data between two computers) and the monitor is not required for any operation. To set/change a screensaver, perform the steps given as follows:

	Right click anywhere on the desktop, and then select Properties from the shortcut menu to open the Display Properties dialog box.
	Click on Screen Saver tab and then from the screen saver drop-down list box select desired screen saver from the displayed list.
	In the Wait box, specify time after which the user wants the screen saver to appear on the monitor's screen.
	Click the Preview button to preview the selected screen saver.
	Click OK to save the settings and exit.

Figure 5.9 Screen Saver Tab

25. Write short notes on the following:

(a) Themes

(b) Toolbar

(c) Window pane area

(d) Address bar and status bar

Ans.: (a) Themes: They are collections of sounds, icons, fonts, colours, and screen savers, which often come with their own background graphics, based on a specific theme. One can select from a range of inbuilt themes from the Theme drop-down box. The Sample window displays a preview of the chosen desktop theme.

(b) Toolbar: It contains shortcut buttons that are used to perform actions found within the menu bar. By default, there are six buttons present on the toolbar each having a specified function. These buttons are listed in Table 5.4.

Table 5.4 Toolbar Buttons

 

Command	Button	Description
Back		It moves back to the previously viewed folders or items.
Forward		It moves forward to the last viewed folders/items (if button is active).
Up		It takes one up one level. If one is working in C:My Documents, then the Up button displays the contents of the C drive.
Search		It initiates the search function, which allows one to locate files or folders stored on the computer or network.
Folders		It displays the folders pane on the left side of the window.
Views		It allows one to select the way to view the contents of the window.

 

 

(c) Window pane area: The window contains two panes: left and right. The left pane also known as common tasks area is divided into various sections: System Tasks, Other Places, and Details section. System Tasks and Other Places contain links to view information relating to the system and access to various system utilities such as My Documents folder and Control Panel. The right pane area includes some icons, which are listed in Table 5.5.

Table 5.5 My Computer Objects

 

Command	Button	Description
3½ Floppy Drive		It allows saving of files on an external drive, that is, floppy disk.
Local Disk		It allows access to the local drives placed within the computer. Generally, it is the C drive, but sometimes a computer has more than one local drive.
CD Drive		It allows access to the CD drive. It serves as a multi-purpose utility allowing one to install software, take back-ups of data, watch and listen to audio visual CDs, etc.
Network Drive		It allows access to a drive that is stored on a network server.

 

 

(d) Address bar and status bar: The address bar is located between the toolbar and the window panes. It displays the current disk drive and folder, such as ‘C:Documents and SettingsMy Documents’. The status bar is located at the bottom of the window and displays the total number of objects (files and sub-folders) in the folder and the space (bytes) they occupy. If a drive or file is selected, it displays the amount of disk free space on the common tasks area as well as on the status bar.

26. What is the use of recycle bin in Windows XP? How items can be restored from it?

Ans.: The recycle bin is a temporary storage area where one can move any files or folders that is no longer needed. To view the contents of the recycle bin, double-click on the Recycle Bin icon placed on the desktop. This opens recycle bin window, which contains a list of deleted items. Items in the recycle bin take up disk space on the hard drive until they are permanently deleted. An item remains in the recycle bin until one decides to permanently delete it or restore it.

One can restore any accidentally deleted file or folder from the recycle bin. To restore an item, select the item(s) and perform any of the following steps:

1. Right-click on the item and select Restore option from the shortcut menu
2. Select Restore this item from the common task area
3. Select Restore from the File menu

27. Explain the different operations that can be performed with Windows Explorer.

Ans.: Windows XP provides a very useful feature called Windows Explorer, which helps to organize files and folders stored on a computer in an efficient manner. It allows arranging files according to one's own needs, and provides optional views for easy scanning of folder contents. In this window, one can also create new files or folders, open, move or copy, and delete existing file or folders. To open Windows Explorer, perform any of the steps given as follows:

	Click Start, point to All Programs, and then select Accessories. Now select Windows Explorer from the submenu that appears.
	Right-click on My Documents folder and select Explore from the shortcut menu.

After performing these steps, Windows XP displays the Windows Explorer window. This window is divided into two panes: folders pane and contents pane. The folders pane of Windows Explorer displays disk drives, folders, and subfolders. These items can be expanded or collapsed by clicking on the plus (+) sign and minus (-) sign symbols that appear to the left of the drive letter, folder, or subfolder name. A (+) means there are subfolders that are not visible. Click on the (+) to view the subfolders. Doing this, the (+) changes to a (-). The contents of the selected drive or folder are displayed in the contents pane by clicking on the item's name or icon in the folders pane. The toolbar present on the Windows Explorer window provides buttons for common actions associated with the contents present in the window.

Changing Sort Order

While searching for a file, it may be easy to locate that file in the contents pane by changing the order in which the files and folders are displayed. One can sort the contents pane by clicking on the desired column heading. For example, in Figure 5.10, the contents pane is sorted by Type column, in ascending order. Note that a triangle will appear next to the column heading to indicate the sort method. For ascending, the triangle points upward (), while for descending, the triangle points downward ().

Figure 5.10 Changing Sorting Order

28. Write in brief on narrator and magnifier.

Ans.:

Narrator

It is a text-to-speech utility for users who are visually impaired. It operates by reading the information available on the screen. This includes contents of the active window, menu options, or the text one has typed. It is designed specifically to work with Notepad, WordPad, Control Panel programs, Internet Explorer, and Desktop.

To open Narrator, Click Start, point to All Programs, and then select Accessories. Now choose Accessibility and select Narrator from the shortcut menu that appears. When Narrator is opened, it shows a message, displaying a brief description about Narrator. Click OK to proceed to Narrator dialog box. This dialog box contains a list options, each having an associated check box. Select the appropriate options and then select Voice to adjust the voice settings.

Magnifier

It is an accessibility utility that makes the screen more readable for users who have impaired vision. It operates by creating a separate window that displays a magnified portion of the screen. One can easily change the magnification level, move or resize the Magnifier window, or drag it to the edge of the screen and lock it into place.

To open Magnifier, click Start, point to All Programs, and then select Accessories. Now choose Accessibility and then select Magnifier from the shortcut menu that appears. When Magnifier is opened, it displays three overlapped windows. The first window shows a message, displaying brief description about Magnifier. Click OK to display the second window, which displays various settings for the Magnifier, whereas the third window shows magnified view of the screen.

29. How are disk cleanup and disk defragmentation helpful to us?

Ans.:

Disk Cleanup

It helps to create free space on the hard drive. It searches the drive, and then displays temporary files, Internet cache files, and unnecessary program files that one can safely delete. To use Disk Cleanup, perform the following steps:

1. Click Start, point to All Programs, and then select Accessories. Now choose System Tools then select Disk Cleanup from the shortcut menu that appears (Figure 5.11). This displays Select Drive dialog box.

   

   Figure 5.11 Select Drive Dialog Box

2. Select the drive from the drop-down box and click OK. This displays the Disk Cleanup dialog box.
3. On the Disk Cleanup tab, scroll through the files to delete list and see which kind of files Windows has selected for removal. Select any additional file types you want to delete, and then click OK.
4. Windows XP displays a message asking you to confirm deletion. Click Yes to delete.

Disk Defragmenter

It searches the hard disk for fragmented files that have been stored in non-contiguous sectors of the disk. It then consolidates fragmented files and folders on the computer's hard disk, so that files and folders are stored in contiguous sectors. As a result, one can access files and folders faster and save new ones more efficiently. To use Disk Defragmenter, perform the following steps:

1. Click Start, point to All Programs, and then select Accessories. Now choose System Tools then select Disk Defragmenter from the shortcut menu that appears. This displays the Disk Defragmenter window.
2. Select the drive you want to defragment and click Defragment to start defragmenting.

30. What are restore points? How can one create and use restore points?

Ans.: Microsoft Windows XP has included system utilities that help to recover from systems that become unstable or unreliable. System restore is one such system utility whose purpose is to restore computer to a previously known working state in the event of a problem. This is done without loss of personal files or data such as word processing documents, spreadsheets, music files, and images.

System restore protects the computer by creating back-ups of vital system configurations and files. These back-ups are known as restore points and are used to revert the system to a previous state. This utility runs in the background and automatically creates a restore point when a trigger event occurs. Trigger events include application installations, AutoUpdate installations, Microsoft Backup Utility recoveries, unsigned-driver installations, and manual creations of restore points. To open system restore, click Start, point to All Programs, and then select Accessories. Now choose System Tools then select System Restore from the shortcut menu that appears. When System Restore is opened, it displays three options: Restore my computer to an earlier time, Create a restore point, and Undo my last restoration.

Creating a Restore Point

By default, Windows XP is configured to automatically create restore points at scheduled times or before some programs are changed. However, one can also manually create restore points. To do this, perform the following steps:

	Select Create a restore point option and click Next.
	Select the restore point and click Next.
	Confirm the restore point.

Using a Restore Point

To restore Windows XP to a previously created restore point, perform the steps given as follows:

	Select Restore my computer to an earlier time option and click Next.
	The window displays in bold a list of dates available. Select the date (restoration point) and then click Next.
	Now click Next to confirm the restoration point.

At this point, you have to confirm, whether you want to continue. Click Next to continue. Now, System Restore shuts down all open applications and reboots the computer. After the computer reboots, a message appears on the screen, which confirms that the restoration to the restore point is complete.

31. Discuss control panel.

Ans.: Control panel is an important part of Windows XP as it provides various options to view and adjust system settings such as adding a new hardware, adding and removing programs (software), managing user accounts, changing settings of the mouse and keyboard, etc. To open the Control Panel, perform any of the steps given as follows:

	Click Start and then click Control Panel.
	Click Start and then click Run. This displays the Run dialog box. Type control or control panel and click OK or press the Enter key.

As one performs any of the above given steps, the Control Panel window appears showing the various shortcut icons for adjusting system settings. Windows XP allows viewing Control Panel in two views: either classic view or category view. In the classic view, all the individual shortcut icons appear with their name while in the category view, icons are grouped into categories which are then displayed. Switching between the views can be performed by clicking on the option (switch to classic view or switch to category view) from the left side of the Control Panel window. The description of most commonly used system settings from control panel is as follows:

	Add hardware: It allows adding a new hardware device to the system.
	Add/remove programs: It allows adding or removing a program or Windows component. It also indicates the size an installed program is occupying and the frequency of usage.
	Printers and faxes: It allows viewing the installed printers and faxes. One can remove the existing printer as well as install a new printer from here.
	System: It allows viewing and specifies various settings for the system including viewing the version of Windows, amount of RAM, speed of the CPU, changing the name of the computer, enabling or disabling hardware devices installed, etc.
	User accounts: It allows creating, managing, and removing user accounts for persons who share your computer. For instance, one can specify the privileges to a user account, add, change, or remove the password, etc.

32. What are the different accessories in MS Windows? Explain their uses?

Ans.: Windows XP OS comes with some basic accessories: calculator, notepad, and paint.

Calculator

A built-in calculator is included in the Windows OS that works just like a handheld calculator, except one has to use it on-screen rather than in one's hand. The calculator can be used in any one of the two views: standard and scientific. In the standard view of the calculator, one can perform common mathematical operations such as addition, subtraction, multiplication, division, etc. On the other hand, in the scientific view of the calculator, one can perform advanced mathematical operations such as trigonometric and statistical operations, calculate logarithm, exponent, factorial, and power. To open the calculator, follow any of the steps given as follows:

	Click Start, point to All Programs, then point to Accessories, and click Calculator from the submenu that appears.
	Click Start and then click Run. This displays the Run dialog box. Type calc and click OK or press the Enter key.

Notepad

Windows accessories include a simple built-in text editor called Notepad that helps to create simple text documents as well as web pages. The default extension for the files created in it is .txt.

To open Notepad, follow any of the steps given as follows:

	Click Start, point to All Programs, then point to Accessories, and click Notepad from the submenu that appears.
	Click Start and then click Run. This displays the Run dialog box. Type notepad and click OK or press the Enter key.

Paint

Windows provides Paint to create and edit graphics. It is a simple and easy to use tool and let to work with bitmap (.bmp) as well as JPEG and GIF graphics. To open Paint, perform any of the steps given as follows:

	Click Start, point to All Programs, then point to Accessories, and click Paint from the submenu that appears.
	Click Start and then click Run. This displays the Run dialog box. Type mspaint and click OK or press the Enter key.

The Paint window contains menu bar, tool box, vertical and horizontal scroll bars, colour box, status bar, and a white rectangular area (called canvas), where one can work with graphics. These are described as follows:

	Menu bar: The Paint contains six menus: File, Edit, View, Image, Colors, and Help.
	Tool box: It contains several tools for creating drawings and text, selecting and erasing part of images, filling colours in images, etc.
	Colour box: It contains several colours and helps to select a colour for image. In the left-end of the colour box is a colour overlapping another colour. The colour on the top is the foreground colour and the colour in the bottom is the background colour. To change the foreground colour, left-click a colour in the colour box while to change the background colour, right-click a colour in the colour box.
	Scroll bar: Paint window has two scroll bars: vertical and horizontal. These scroll bars let one to scroll and view the portion of image currently not visible on the screen.
	Status bar: It displays messages and measurements as one works in Paint. For example, it displays the information related to a tool as mouse is moved over it in the tool box.

Multiple-choice Questions

1.  The OS that allows only one program to run at a time is called __________.

(a) Batch processing

(b) Embedded

(c) Real time

(d) Multitasking

2.  What allows the user to run two or more applications on the same computer so that he or she can move from one to the other without closing the application?

(a) Virtual storage

(b) Multiprocessing

(c) Multitasking

(d) Multiprogramming

3.  The memory management scheme that allows the processes to be stored non-contiguously in the memory is called __________.

(a) Paging

(b) Spooling

(c) Swapping

(d) None of these

4.  With which memory, the system can run programs that are actually larger than the primary memory of the system?

(a) Cache memory

(b) Primary memory

(c) Virtual memory

(d) None of these

5.  Which of the following OS is GUI based?

(a) Microsoft Windows

(b) MS-DOS

(c) Linux

(d) None of these

6.  __________ is primarily used to prevent damage to the phosphor element present in the monitor.

(a) Screen saver

(b) System restore

(c) Themes

(d) Appearance

7.  Which of the following utilities is used to search the hard disk for fragmented files?

(a) Disk Cleanup

(b) System Restore

(c) Disk Defragmenter

(d) Backup

8.  Collections of sounds, icons, fonts, colours, and screen saver are known as __________.

(a) Appearance

(b) Themes

(c) Colours

(d) Settings

9.  Which of the following files and folders does Recycle Bin store?

(a) Hidden files and folders

(b) Deleted files and folders

(c) Files and folders in the Floppy drive

(d) None of these

10.  The functions of Windows Explorer are to __________.

(a) Organize files and folders

(b) Change the settings

(c) Add new programs

(d) All of these

Answers

1. (a)

2. (c)

3. (a)

4. (c)

5. (a)

6. (a)

7. (c)

8. (b)

9. (b)

10. (a)