The response of an interpreter is fast as compared to the compiler. But, interpreter is a timeconsuming translation method because each statement must be translated every time, it is executed from the source program.
Difference between Compiler and Interpreter
|S.No.||Basis of difference||Compiler||Interpreter|
|1.||Definition||Scans the entire source program first and then translates it into machine code.||Translates the program line by line.|
|2.||Working||Converts the entire program to machine code and when all the syntax errors are removed, execution takes place.||Each time the program is executed, every line is checked for syntax error and then converted to equivalent machine code.|
|3.||Execution time||Execution time is less.||Execution time is more|
|4.||Debugging rate||Slow for debugging.||Good for fast debugging.|
|5.||Memory||Requires more main memory.||Requires less min memory.|
|6.||Code security||Security of source code.||No security of source code.|
Q.11. Discuss the functions of operating system and classify different types of operating systems.(2013-14)
Or What is an operating system? What are the major functions of an operating system and how are these incorporated in an operating system you are familiar with?(2009-10)
Or Describe the role of network operating systems.(2008-09)
Or What is an operating system? Briefly explain its various functions in detail.(2014-15)
Or Give names of any five different computer operating systems.(2015-16)
Ans. Operating System: This is a system software that makes the hardware usable. It makes the computing power conveniently available to users, by managing the hardware carefully to achieve good performance.
An operating system is a program that acts as an intermediary between a user of a computer and the computer hardware. The purpose of operating system is to provide an environment in which a user can execute programs. It comprises a set of software packages that can be used to manage interactions with the hardware. The following elements are generally included in this set of software:
1. Kernel: Performs the very basic functions required by the computer installation.
2. Shell: Allowing communication with the operating system via a control language.
3. File System: The file system allows files to be recorded in a tree structure.
An operating system plays a crucial role as a resource manager and the coordinator of devices. It makes use of resources like CPU time, files and input/output devices to perform its various tasks. These resources are provided during the creation of a process or are allocated while the process is running. It also controls the access of processes to the resources that are defined by a computer system.
The functions of operating system are as follows:
1. Initial Loading of Programs: When a computer system is switched ON or booted, an operating system is automatically loaded.
2. Process Management Function: A process can be thought of as a program in execution. It needs certain resources including CPU time, memory files and input/output devices, to accomplish its task. These resources are either given to the process when it is created, or allocated to it while it is running.
3.Memory Management Function: Main memory is central to the operation of the modern computer system. There are different memory management schemes. Selection of a memory management scheme for a specific system depends on many factors especially on the hardware design of the system.
4. Device Management Function: One of the purposes of an operating system is to hide the peculiarities of specific hardware devices from the user. For example in UNIX.
5. File Management Function: It is one of the most visible components of operating systems. Computer can store information on several different types of physical media like magnetic tape, magnetic disk, etc.
6. Secondary Storage Management Function: The main purpose of a computer system is to execute programs. These programs with the data they access, must be in main memory during execution.
7. Network Management Function: A distributed system is a collection or processors that do not share memory, peripheral devices or a clock. Operating systems generalise network access a form of file access, with the details of networking being contained in the network interface’s device driver.
8. Protection and Security Management Function: Protection refers to a mechanism for controlling the access of programs, processes or users to the resources defined by a computer system. This mechanism must provide a means for specification of controls to be imposed, together with a means of enforcement.
Different Types of Operating Systems: Based on computers they control and applications they support, operating systems are classified as:
1. Real Time Systems: These are specially designed to respond to events that happen in real time. It has well-defined, fixed time constraints. Processing must be done within the defined constraints or else the system will fail. Real time systems can be hard real time system and soft real time system. For example, HDTV receiver and display.
2. Single User, Single Task Systems: A single user operating system is a type of operating system that is developed and intended for use on a computer or similar machine that will only have a single user at any given time.
A single user operating system that is a single task system is developed for use with a computer or electronic device that will only run one application at a time.
For example, Windows 95, Windows NT workstation.
3. Single User, Multitasking Systems: It is a type of multi programming operating system. When a program execute (using the CPU), it is also known as task. A multitasking OS allows two or more tasks to run simultaneously in a single-user system. Multitasking operation is one of the mechanisms that multiprogramming OS employs in managing the computer resources.
Multiprocessing Operating System: In multiprocessing OS, multiple CPUs (or processors) are attached in a single computer and they run more than one program at one time. For example, Windows (Microsoft) and Macintosh (Apple) platforms are the most popular single user, multitasking OS.
4 Multi user. Multitasking Systems: A multiuser operating system allows many different users to take advantage of the computer’s resources simultaneously. It is also called as time sharing operating system.
A time sharing OS allows many users’ programs to run simultaneously in multi-user system. In this system, a time slice is decided by the OS (suppose, 4 milliseconds). CPU runs first program for one time slice, then second program for other time slice and so on. After the last program, CPU again runs the first program one time slice and continue. As the CPU switches repeatedly from one user’s program to another, each user are given impression that CPU is running only his/her only program while actually one computer is shared among many users.
For example, UNIX, LINUX, etc.
Role of Network Operating Systems
The network operating system provides certain services to programs and users of those programs, who are associated over the network. Some of these functions are:
1. The system must be able to load a program into memory and run it.
2. An executing program require input/output which involve a file and input/output device.
3. User programs may need to read and write files. The operating system must be able to create, modify and delete files by name.
4. It provides detection of errors.
5. It helps to exchange information with another process.
6. It keeps track of number of users, user programs and how much or what kind of computer resources are used by them.
Q.12. What are the basic features of the Windows operating system? Why has it become so popular?
Or Give a brief history of Windows operating system. Or Discuss the tools and commands of Windows 98 operating system.
Ans. Windows Operating System: Till a few years back, all operating systems (like DOS and UNIX) were command based. It means whatever one wanted from the operating system, one could tell the OS by typing a command. One has to remember the commands for the command based OS.
In present days, the demand has increased for an operating system in which the users need not to remember the commands instead of giving command statements, the user chooses and selects some graphical icons positioned on the screen for some actions. This kind of icon based operating environment is called Graphical User Interface. The GUI (as pronounced gooey) provides a means of interaction with the system using windows and mouse driven environment. It helped to overcome the problem of learning different set of commands to run different programs and applications windows in such operating system. Windows 3.1, Windows 95, Windows 98 and Windows 2000 are the various versions of Windows OS Window is called operating environment and not operating system because, it works with DOS at the background and only supplies the support for GUI. –
Windows environment reduces complexities involved in running other software packages because running and operation under a window are general and common. This is the reason why it has become popular and hence, it is applicable to different applications. GUI is a kind of multiprogramming software that enables a user to run several application programs concurrently. It allows you to use multiple programs simultaneously and view them on separate screen, which was not possible in command line environment. Different applications run in their respective windows and number of windows can be opened to run different programs. These save valuable time of loading/unloading packages as one can very comfortably switch between packages (currently opened) without closing previous one.
Data can also be shared between packages, e.g. you can cut a table from Excel sheet and paste it into MS Word, similarly you can draw a picture in paint and again it can be used in some other applications.
Dynamic Data Exchange (DDE) and Object Linking and Embedding (OLE) features allow the data to link across packages, i.e. any change mode onto source application will automatically update destination application as well.
Concepts of GUI: A GUI is based on the following concept:
Consistency: Consistency in operating the programs should be maintained, i.e. there is only oneway to call a menu, execute a file, etc.
WYSIWYG Concept: What you see is what you get. The program should appear exactly the way it appears, when printed with all formatting.
Windows: The program should operate within windows on the screen. These windows are immovable, resizable, minimised, etc. i.e. under user control.
Dialog Box: For communicating with the user, dialog box is used in a GUI system.
Mouse: A pointing device is used along with the keyboard in GUI based systems. The basic functions of a mouse are pointing, clicking, double clicking and dragging.
Tools and Commands of Windows Operating System
The windows tools and commands that one should be aware of include the following:
1. Disk management tools including format, CHKDSK, defrag and NT Backup.
(a) CHKDSK: This command verifies a storage volume (hard disk, partition, floppy disk, flash
drive, etc. for file system integrity. Its syntax is:
CHKDSK volume letter: path filename (/F] [/P] [/R] [X] in DOS. Options included in CHKDSK command are:
/F: Fixes errors on the volume (without/E, CHKDSK only detects errors)
/P: Forces full verification
/R: Searches for defective sectors and recovers legible information (applies/F)
/IX: Unmounts the volume before processing if needed.
Note: Unmounting temporarily invalidates all pointers/handlers to the volume until process is completed. On Windows, it can be started as:
Windows explorer > Properties > Tools > Error checking > Check now (CHKDSK)
(b) Defrag: Defragmenting a disk involves analysing the disk and then consolidating fragmented files and folders so they occupy a contiguous space thus increasing performance during file retrieval.
Windows explorer Properties + Tools → Defragment now
(c) NT Backup: If one wants to have backup of the system he/she can run the backup utility. In
Windows 7, Start → Control panel System’and security Backup and restore.
In other versions, Start → All programs Accessories System tools → Backup.
2. System Tools: Desktop controls various system tools, such as Disk cleaner, Disk defragmenter, that can run on the multiple computers simultaneously.
(a) Disk Cleanup: This utility allows us to get the disk cleaned up. We can run ‘Disk cleanup’ to free up space on hard drive.
Select start > Program > Accessories > System tools > Disk cleanup
(b) Disk Defragmenter: We can use disk defragmenter in order to rearrange files and unused space on hard disk so that programs run faster.
Select Start > Program > Accessories > System tools > Disk defragmenter
(C) Drive Converter: Drive converter converts the drive to the FAT 32 file system, an enhancement of the file allocation table file system format.
(d) Backup: You can use ‘Backup’ to backup files on the hard have a greater set of disk. You can backup files to floppy disks at tape drive or built-in commands which another computer on your network.
(e) Resource Meter: It monitors the system resources whichour programs are using. It can be started as:
Start > Programs > Accessories > System tools > Resource metre
(f) SCANDISK: You can use scandisk to check the hard disk for logical and physical errors. It can be started as:
Start > Programs > Accessories > System tools > Scandisk
But in MS-DOS, the SCANDISK command is a disk diagnostic utility. SCANDISK was a replacement for the CHKDSK utility, starting with later versions of MS-DOS. Its primary advantages over that it is more reliable and has the ability to run a surface scan which finds and marks ba the disk.
Execution of Commands
In Windows Operating system, icons help you to execute commands quickly. An icon is a graphical symbol, which represents a window element like file, folder or shortcut. To execute a command by using and icon, simply double – click its icon. Most common icons are:
- Application Icon: To use any application Like games, paint, etc.
- Shortcut Icon: Shortcut for various files or folders.
- System Icon: containing system related properties and tools.
- Document Icon: contains documents which are used or saved by the user.
- Disk drive Icon: containing various disk drives depending on the partitions made in the system.