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Thursday, March 18, 2010

operating systems question and answer

1. Define operating systems?

Operating systems is a set of program that manages the computer hardware it provides the basis for application programs and acts as an intermediary between a user of a computer and computer hardware.

2.Write the functions of an OS.

*Memory management

*Processor management

*Management &control of i/o devices.

*Interrupt handling

*Accounting

*Automatic job sequencing.


3.What is multiprocessing?

A multiprocessing is one in which there are more than one cup’s interleaved with each other. The simultaneous processing of a no of processes by a no of processors simultaneously at the same time is multiprocessing.

4.Define the Views of OS.


System View :

- Memory Allocation

- Protection

- Co-ordination between computer peripherals

User View :

- Easy to use

- Resource sharing


6.Define multiprogramming.

The ability of keeping several jobs in memory at one time where the cpu is switched back and forth among them to increase cpu utilization and to decrease the total time needs to execute the jobs is known as multiprogramming.

7.What is time-sharing?

Time-sharing or multitasking is a logical extension of multiprogramming multiple jobs are executed by the cpu switching between them but the switches occur so frequently that the users may interact with each program while it is running.

8.State the advantages of multiprocessor systems.

*Increased throughput

*Economy of scale

*Increased reliability

9.Define “fault tolerant” system.

The advantage of multiprocessor system is there reliability since the function are distributed among several processors the failure of one processor close not halt the system but only slows clown the system.

The ability to continue providing service in proportion to the non-failed level of hardware is called as graceful degrading systems that are designed for graceful degradation are called fault tolerant systems.

10.What are the characteristics of an OS?

*User friendly

*Allows sharing of resources.

*Provide adequate security for os programs as well as for user programs.

*Protect user from one another.

*Provide automatic job sequencing.

11.What are the advantages of multiprogramming?

*Multiprogramming provides an environment where the various system resources are utilized efficiently.

*They are (multiprogramming os)fairly sophisticated.

*Supports multiple simultaneous interactive users.

*Provides better system utilization.

12.Illustrate the factors that usually determine the degree of multiprogramming.

*The no of programs residing in primary memory.

*Passing of the control to the cpu rapidly between these programs.

*Protection of users from one another since there is a possibility for them to accurse other process area.

13.Define microprogramming.

Microprogramming run in high control storage they are formed from individual microinstruction that is much elementary in nature & spacer in function that conventional machine language instruction.

14.State the various system calls.

*Process memt.

*Main memory mgmt.

*File mgmt.

*I/O system mgmt.

*Secondary storage mgmt.

*Networking.

*Protection system.

*Command interpreter system.

15.What are the major activities of an os in regard to process management?

*Creating and deleting both user and system processors.

*Suspending *resuming processors.

*Providing mechanisms for process synchronization.

*Providing mechanisms for process communication.

*Providing mechanisms for deadlock handling.

16.What are the three-magor activities of as os in regard to secondary storage mgmt?

*Free space mgmt.

*Storage allocation

*Disk scheduling.

17. What are the three major activities of as os in regard to file mgmt?

*Creating & deleting files.

*Creating & deleting directories.

*Supporting primitives for manipulating files * directories.

*Mapping files on to secondary storage

*Backing up files on stable storage media.

18.State the parts of i/o subsystem.

*Memory mgmt component includes buffering caching & spooling.

*A general device driver interface.

*Drivers for specific h/w devices.

19.Define distributed system.

Distributed system is a collection of processors that do not share memory peripheral devices or a clock. each processors has it’s own local memory .the processor in the system are connected by a “communication link”.

20.What is the purpose of the command interpreter?

Command interpreter is the interface between user and operating system many commands are given to the operating system by control statements.

A program called “command line interpreter” reads and interprets controls statements this program is executed automatically.

21.Write the various operating system services?

*Program execution.

*I/O operations.

*File system manipulations.

*Communications.

*Error detection

*Resource allocation.

*Accounting.

*Protection.

22.Define system call.

System calls provide the interface between a process and the operating system these calls are available in assembly language instructions.

23.What are the 2 different models of communications used?

*Message passing model

*Shared memory model.

24.What are system programs?

*Program execution.

*I/O operations.

*File system manipulations.

*Communications.

*Error detection

*Resource allocation.

*Accounting.

25.Define the term system utilities.

Most operating systems are supplied with programs that solve common problems or perform some operations.

Example programs are-database systems, spread sheets.

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