Operating System
‏إظهار الرسائل ذات التسميات Operating System. إظهار كافة الرسائل
‏إظهار الرسائل ذات التسميات Operating System. إظهار كافة الرسائل
Solved MCQ on Core Operating System Principle set-13

Solved MCQ on Core Operating System Principle set-13

8:06 ص اضافة تعليق
1) In memory management, a technique called as paging, the physical memory is broken into fixed sized blocks called .........

A. pages

B. frames

C. blocks

D. segments


2) Which method is used to recover from deadlock?

A. Process termination

B. Resource preemption

C. Resource non-preemption

D. Process termination and Resource preemption


3) Saving the state of the old process and loading the saved state of the new process is called ....

A. context switch

B. static

C. multi programming

D. none of the above


4) The degree of Multiprogramming is controlled by ......

A. CPU scheduler

B. context switching

C. long term scheduler

D. medium term scheduler


5) Input transfers are done in advance and output transfers are done after sometimes in which of these technique?

A. Spooling

B. Buffering

C. Swapping

D. Paging


6) A binary semaphore .........

A. has the values one or zero

B. is essential to binary computers

C. is used only for synchronization

D. is used only for mutual exclusion


7) A scheduling algorithm is fair .......

A. if no process faces starvation.

B. if a process is starved, detect it and run it with high priority

C. if it uses semaphores

D. only if a queue is used for scheduling


8) Which of the following is also known as Double buffering?

A. anticipated buffering

B. buffer swapping

C. circular buffering

D. swapping buffering


9) .......... is the ability of a system to continue functioning in the event of partial system failure.

A. fault avoidance

B. fault tolerance

C. fault detection

D. fault recovery


10) Virtual memory is .........

A. an extremely large main memory

B. an extremely large secondary memory

C. an illusion of extremely large main memory

D. a type of memory used in super computers


11) Error handling and I/O interrupt handling are the functions of ......

A. I/O device Handler

B. I/O traffic controller

C. I/O scheduler

D. I/O buffer


12) In a multi-threaded environment..........

A. each thread is allocated with new memory from main memory

B. main thread terminates after the termination of child threads

C. every process can have only one thread

D. none of the above


13) The kernel keeps track of the state of each task by using a data structure called ......

A. process control block

B. user control block

C. memory control block

D. hardware control block


14) A virtual device is a ..........

A. dedicated for none purpose

B. shared device converted to a dedicated device

C. dedicated device converted to a shared device

D. shared device


15) CPU scheduling is the basis of ...........operating system.

A. batch

B. real time

C. multiprogramming

D. monoprogramming


16) ......... is a high speed cache used to hold recently referenced page table entries a part of paged virtual memory.

A. Translation look a side buffer

B. Inverse page table

C. Segmented page table

D. Indexed page table


17) A technique that smooths out peaks in I/O demand is ........

A. spooling

B. buffering

C. swapping

D. paging


18) In kernel model, the operating system services such as process management, memory management are provided by the kernel.

A. monolithic

B. micro

C. macro

D. Complex


19) A process is said to be in ........... state if it was waiting for an event that will never occur.

A. safe

B. unsafe

C. starvation

D. dead lock


20) Which of the following is an example of spooled device?

A. The terminal used to enter the input data for a program being executed

B. The secondary memory device in a virtual memory system

C. A line printer used to print the output of a number of jobs

D. None of the above

Answers:

1) B. frames
2) D. Process termination and Resource preemption
3) A. context switch
4) C. long term scheduler
5) B. Buffering
6) A. has the values one or zero
7) A. if no process faces starvation
8) B. buffer swapping
9) B. fault tolerance
10) C. an illusion of extremely large main memory
11) A. I/O device Handler
12) B. main thread terminates after the termination of child threads
13) A. process control block
14) B. shared device converted to a dedicated device
15) C. multiprogramming
16) A. Translation look a side buffer
17) B. buffering
18) A. monolithic
19) D. dead lock
20) C. A line printer used to print the output of a number of jobs


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Objective Questions on Core Operating System set-12

Objective Questions on Core Operating System set-12

7:56 ص اضافة تعليق
1) An optimal scheduling algorithm in terms of minimizing the average waiting time of a given set of process is ...

A. FCFS scheduling

B. Round robin scheduling algorithm

C. Shortest job first scheduling algorithm

D. Priority scheduling algorithm


2) The hardware mechanism that enables a device to notify the CPU is called .......

A. polling

B. interrupt

C. system call

D. none of the above


3) In the running state ........

A. only the process which has control of the processor is found

B. all the process waiting for I/O to be completed are found

C. all the processes waiting for the processor are found

D. none of the above


4) Which technique was introduced because a single job could keep both the CPU and the I/O devices busy?

A. Time sharing

B. Spooling

C. Preemptive scheduling

D. Multiprogramming


5) RMA works on static priorities while EDF algorithm works on ........

A. starvation

B. dynamic priorities

C. RR scheduling

D. FIFO scheduling


6) In the ........... method of data transfer, the participation of the processor is eliminated during data transfer.

A. buffering

B. caching

C. direct memory access

D. indirect memory access


7) Inter process communication can be done through ....

A. mails

B. messages

C. system calls

D. traps


8) RR scheduling is most suitable for ........

A. time shared OS

B. distributed OS

C. real time OS

D. an Ordinary OS


9) The aim of ......... transparency is to ensure that the movement of the object is handled automatically by the system in a user transparent manner.

A. location

B. name

B. migration

D. scaling


10) ........... is a memory management scheme that permits the physical address space of a process to be noncontiguous.

A. Paging

B. Segmentation

C. Virtual memory

D. main memory


11) Context switching is ........

A. part of spooling

B. part of polling

C. part of interrupt handling

D. part of paging


12) The normal functioning of an RPC may get disrupted due to ..........

A. call message gets lost

B. response message gets lost

C. callee node and caller node crashes and is restarted

D. All of the above


13) Mutual exclusion is referred as .......

A. if one process is in a critical region others are excluded

B. prevents deadlock

C. requires semaphore to implement

D. is found only in the windows NT operating system


14) IFO scheduling is ..........

A. preemptive

B. non-preemptive

C. deadline scheduling

D. RR scheduling


15) .......... deals with the process of deciding which process should be assigned to which processor.

A. Process migration

B. Processor allocation

C. threads

D. none of the above


16) Which scheduler controls the degree of multiprogramming?

A. Short term scheduler

B. Long term scheduler


C. Middle term scheduler

D. Pre term scheduler


17) Safe state is .......

A. deadlock state

B. non-deadlocked state

C. polling state

D. spooling state


18) ........ time is defined as the time period for which the execution of the process is stopped for transferring its information to the destination node.

A. turn around

B. latency

C. freezing

D. execution



19) The principle of locality of reference justifies the use of

A. virtual memory

B. interrupts

C. main memory

D. cache memory


20) For a multiple instances of resource type which algorithm is used .......

A. divide and conquer algorithm

B. banker's algorithm

C. partition algorithm

D. sorting algorithm


Answers:

1) C. Shortest job first scheduling algorithm
2) B. interrupt
3) A. only the process which has control of the processor is found
4) D. Multiprogramming
5) C. RR scheduling
6) C. direct memory access
7) B. messages
8) A. time shared OS
9) B. migration
10) A. Paging
11) C. part of interrupt handling
12) D. All of the above
13) A. if one process is in a critical region others are excluded
14) B. non-preemptive
15) B. Processor allocation
16) B. Long term scheduler
17) B. non-deadlocked state
18) C. freezing
19) D. cache memory
20) B. banker's algorithm


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Interview Questions on Operating System Basis set-11

Interview Questions on Operating System Basis set-11

7:13 ص اضافة تعليق
1) Which of the following is crucial time while accessing data on the disk?

A. Seek time

B. Rotational time

C. Transmission time

D. Waiting time


2) What is the primary job of the operating system is a computer?

A. Command resources

B. Manage resources

C. Provide utilities

D. Be user friendly


3) The ......... is a user process that initiates a remote procedure call.

A. client

B. server

C. network

D. operating system


4) Which of the following memory allocation scheme suffers from external fragmentation?

A. Segmentation

B. Pure demand paging

C. Swapping

D. Paging


5) Which of the following is used to removal of process from active contention of CPU and reintroduce them into memory later?

A. Interrupt

B. Swapping

C. Signal

D. Thread


6) The operating system manages .....

A. memory

B. processor

C. disk and I/O devices

D. all of the above


7) Information about a process is maintained in a .........

A. stack

B. translation look a side buffer

C. process control block

D. program control block


8) Paging .........

A. solves the memory fragmentation problem

B. allows modular programming

C. allows structured programming

D. avoids deadlock


9) Which is not the layer of the Operating system?

A. Kernel

B. Shell

C. Application program

D. Critical Section


10) Distributed OS works on the ............ principle.

A. file foundation

B. single system image

C. multi system image

D. networking image


11) The collection of processes on the disk that is waiting to be brought into memory for execution forms the .......

A. ready queue

B. device queue

C. input queue

D. priority queue


12) In ....... condition, processes are allowed to request for new resources without releasing the resources that they are currently holding.

A. Mutual exclusion

B. Hold and wait

C. No preemption

D. Circular wait


13) The time taken by the disk arm to locate the specific address of a sector for getting information is called .....

A. rotational delay

B. seek time

C. search time

D. response time


14) The principle of locality of reference justifies the use of ........

A. virtual memory

B. interrupts

C. main memory

D. cache memory


15) In .......... condition, a resource that has been allocated to a process becomes available for allocation to another process only after it has been voluntarily released by the process holding it.

A. Mutual exclusion

B. Hold and wait

C. No preemption

D. Circular wait


16) Identify the odd thing in the services of operating system ...

A. Accounting

B. Protection

C. Error detection and correction

D. Dead lock handling


17) Multiprocessing ...........

A. makes the operating system simpler

B. allows multiple processes to run simultaneously

C. is completely understood by all major computer vendors

D. allows the same computer to have the multiple processors


18) In ............. condition, two or more processes must form a circular chain in which each process is waiting for a resource that is held by the next member of the chain.

A. Mutual exclusion

B. Hold and wait

C. No preemption

D. Circular wait


19) Which of the following is not advantage of multiprogramming?

A. Increased throughput

B. Shorter response time

C. Decreased operating system overhead

D. Ability to assign priorities of jobs


20) Which is not a state of the process?

A. Blocked

B. Running

C. Ready

D. Privileged


Answers:

1) A. Seek time
2) B. Manage resources
3) A. client
4) A. Segmentation
5) B. Swapping
6) D. all of the above
7) C. process control block
8) A. solves the memory fragmentation problem
9) D. Critical Section
10) B. single system image
11) C. input queue
12) B. Hold and wait
13) B. seek time
14) D. cache memory
15) C. No preemption
16) C. Error detection and correction
17) D. allows the same computer to have the multiple processors
18) D. Circular wait
19) C. Decreased operating system overhead
20) D. Privileged


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MCQ on Operating System Fundamental set-10

MCQ on Operating System Fundamental set-10

6:10 ص اضافة تعليق
1) The process of storing extra or duplicate information used for rebuilding the lost information in event of disks failure is known as ...

A. stripping

B. redundancy

C. disk array

D. RAID


2) A thread that is to be canceled is often referred to as the ....

A. target thread

B. thread cancellation

C. asynchronous cancellation

D. defined cancellation


3) ........... ensures the every message sent to a group of receivers will be delivered to either all of them or none of them.

A. Ordered delivery

B. Atomicity

B. Survivability

D. Realiability


4) An arrangement of record in a sequence in which they arrive is known as a ...........

A. pile

B. file

C. disk

D. directory


5) ........... also known as monitor mode.

A. User mode

B. System mode

C. Unprivileged mode

D. Process mode


6) The technique, for sharing the time of a computer among several jobs, which switches jobs so rapidly such that each job appears to have the computer to itself, is called ........

A. time sharing

B. time out

C. time domain

D. multitasking


7) For batch and payroll applications which of the following file organization is better ........

A. random file

B. sequential file

C. indexed file

D. hashed file


8) Name the scheduler that selects among the processes that are ready to execute and allocates the CPU to one of them.

A. Long term scheduler

B. Medium term scheduler

C. Job scheduler

D. Short term scheduler


9) Failure during inter-process communication may be due to .....

A. loss of request transfer unit

B. single datagram messages

C. multi datagram messages

D. message passing


10) The process of direct mapping by using some faster algorithms is called as .........

A. hashing

B. searching

C. sorting

D. indexing


11) Name the system in which the processors do not share memory and each processor that its own local memory.

A. Tightly coupled system

B. Parallel processing system

C. Loosely coupled system

D. Batch processing system


12) Which technique was introduced because a single job could not keep both the CPU and I/O devices busy?

A. Time-sharing

B. Spooling

C. preemptive scheduling

D. Multiprogramming


13) Those directories in which the root directory has all system file and no other sub-directory is known as ...

A. flat directory

B. single directory

C. hierarchical directory

D. indexed directory


14) Which is responsible for maintaining all the important abstractions of the operating system?

A. Kernel

B. System libraries

C. System utilities

D. Daemons


15) A four message reliable IPC protocol for client server communication works as ........

A. request, reply, acknowledgment

B. reply, acknowledgment, request, acknowledgment

C. request, acknowledgment, reply, acknowledgment

D. request, request, reply, acknowledgment


16) A path name that starts at root directory is ..........

A. absolute

B. relative

C. hybrid

D. hierarchical


17) Where does the problem of fragmentation occur?

A. Static storage allocation

B. Static allocation storage

C. Stack allocation with dynamic binding

D. Heap allocation


18) Idempotency basically means .........

A. reliability

B. repeatability

C. Survivability

D. flexibility


19) All path names are specified relative to the working directory ........

A. absolute path name

B. relative path name

C. hybrid path name

D. hierarchical path name


20) The time taken by the disk arm to locate the specific address of a sector for getting information is called ........

A. rotational latency

B. seek time

C. search time

D. response time

Answers:

1) B. redundancy
2) A. target thread
3) B. Atomicity
4) A. pile
5) B. System mode
6) A. time sharing
7) B. sequential file
8) D. Short term scheduler
9) B. single datagram messages
10) A. hashing
11) C. Loosely coupled system
12) D. Multiprogramming
13) A. flat directory
14) A. Kernel
15) C. request, acknowledgment, reply, acknowledgment
16) A. absolute
17) D. Heap allocation
18) B. repeatability
19) B. relative path name
20) D. response time


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Solved MCQ on Operating System Basis set-9

Solved MCQ on Operating System Basis set-9

5:47 ص اضافة تعليق
1) The process is ........

A. an instance of a program in execution

B. a program only

C. a processor state

D. the kernel state


2) The mechanism that brings a page into memory only when it is needed is called .....

A. segmentation

B. fragmentation

C. demand paging

D. page replacement


3) The two paradigms if IPC are ............ and .......

A. call, reply

B. shared memory, message passing

C. send, receive

D. call by value, call by reference


4) A program is passive while a process is ..........

A. inactive

B. spontaneous

C. active

D. impulse


5) FIFO scheduling is ..........

A. preemptive scheduling

B. non preemptive scheduling

C. deadline scheduling

D. fair share scheduling


6) ......... ensures that once transaction completes successively, the results of the operations become permanent.

A. serializability

B. synchronizability

C. atomicity

D. durability


7) A process is created and is initially put in the ........

A. ready queue

B. device queue

C. i/o queue

D. waiting queue


8) Which directory implementation is used in most of the Operating System?

A. single level directory structure

B. two level directory structure

C. tree directory structure

D. acyclic directory structure


9) Isolation property is also know as .........

A. Performance

B. Serializability

C. Durability

D. Atomicity


10) A thread is a ..........

A. task

B. process

C. program

D. light weight process


11) The interval from the fine submission of a process to the time of completion is the ......

A. waiting time

B. blocked time

C. turnaround time

D. response time


12) The term "Operating System" means ..........

A. a set of programs which controls computer working

B. the way a computer operator works

C. conversion of high-level language in to machine level language

D. the way a floppy disk drive operates


13) Generally we have user level threads and ...........

A. Programmer level thread

B. kernel level thread

C. program level thread

D. process level thread


14) To ensure that the ......... condition never occurs in the system, we must guarantee that, whenever a process requests a resource, it does not have any other resource.

A. mutual exclusion

B. no-preemption

C. circular waits

D. hold and wait


15) Resource locking ........

A. allows multiple tasks to simultaneously use resource

B. forces only on task to use any resource at any time

C. can easily cause a dead lock condition

D. in not used for disk drives


16) A program responsible for assigning the CPU to the process that has been selected by the short term scheduler is known as .........

A. scheduler

B. dispatcher

C. debugger

D. compiler


17) The .......... instruct Kernel to do various operations of the calling program and exchange data between the Kernel at the program.

A. shell

B. editors

C. system calls

D. commands


18) Which of the following buffering strategies are used in interprocess communication?

A. null pointer

B. single message buffer

C. multiple message buffer

D. all of the above


19) The process of splitting of data into equal size partitions over multiple disks is known as .....

A. data stripping

B. array of disks

C. RAID

D. SCAN


20) Pipes allow transfer of data between processor in a .......... manner.

A. last in first out

B. shortest job first

C. multilevel queue

D. first in first out

Answers:

1) A. an instance of a program in execution
2) C. demand paging
3) B. shared memory, message passing
4) C. active
5) B. non preemptive scheduling
6) D. durability
7) A. ready queue
8) C. tree directory structure
9) B. Serializability
10) D. light weight process
11) C. turnaround time
12) A. a set of programs which controls computer working
13) B. kernel level thread
14) D. hold and wait
15) B. forces only on task to use any resource at any time
16) B. dispatcher
17) C. system calls
18) D. all of the above
19) A. data stripping
20) D. first in first out


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Solved Objective Questions on Operating System set-8

Solved Objective Questions on Operating System set-8

8:41 ص اضافة تعليق

1. A small program which loads OS into the memory is called as ...........
Objective Questions on Operating System
System management components (Photo credit: Wikipedia)

A) ROM

B) bootstrap loader

C) BIOS

D) RAM



2. Virtual memory is ..............

A) Simple to implement

B) Used by all major commercial OS

C) Less efficient memory utilization

D) Less effective



3. A special purpose register that is set to the highest address occupied by the OS code is ...........

A) fence register

B) general purpose register

C) protection register

D) control register



4. As OS program module that selects the next job to be admitted for execution is called as .....

A) scheduler

B) compiler

C) throughput

D) dispatcher





5. Multiprogramming systems .................

A) are easier to develop than single programming systems.

B) execute each job faster

C) execute more jobs in the same time.

D) are used only on large main frame computers



6. SSTF stands for ........................

A) Small seek Time First

B) Simple Seek Time First

C) Shortest Seek Time First

D) Synchronous Seek Time First



7. The program is known as .................. which interacts with the inner part of called kernel.

A) compiler

B) device driver

C) protocol

D) shell



8. Semaphore can be used for solving ............

A) wait & signal

B) deadlock

C) synchronization

D) priority



9. The number of processes completed per unit time is known as ............

A) output

B) throughput

C) efficiency

D) capacity



10. On what principle does Distributed OS work?

A) File foundation

B) Single system image

C) Multi system image

D) Networking image


Answers:



1. A small program which loads OS into the memory is called as ...........

B) bootstrap loader

2. Virtual memory is ..............

B) Used by all major commercial OS

3. A special purpose register that is set to the highest address occupied by the OS code is ...........

A) fence register

4. As OS program module that selects the next job to be admitted for execution is called as .....

A) scheduler

5. Multiprogramming systems .................

C) execute more jobs in the same time.

6. SSTF stands for ........................

C) Shortest Seek Time First

7. The program is known as .................. which interacts with the inner part of called kernel.

D) shell

8. Semaphore can be used for solving ............

C) synchronization

9. The number of processes completed per unit time is known as ............

B) throughput

10. On what principle does Distributed OS work?

B) Single system image



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Solved MCQ Questions on Operating System set-7

Solved MCQ Questions on Operating System set-7

6:32 م اضافة تعليق

1. Operating System means ........................

A) a set of programs which controls computer working.

MCQ Questions on Operating System
Operating System (Photo credit: Wikipedia)
B) a way of computer drives works

C) a set of devices and programs

D) All of the above



2. The basic types of OS are ...................

A) batch and time sharing

B) sequential and real time

C) direct and interactive

D) batch and interactive



3. The simplest way of deadlock is to ...

A) preempt a resource

B) rollback

C) kill one of the processes

D) lock one of the processes



4. Throughput of a system is

A) Number of programs processed by it per unit time

B) Number of times the program is invoked by the system

C) Number of requests made to a program by the system

D) None of the above



5. Which of the following is not OS layer?

A) Kernel

B) Shell

C) Application Programs

D) Critical Section



6. Round robin scheduling is essentially the preemptive version of ...........

A) first in first out

B) shortest job first

C) shortest remaining

D) longest time first



7. The process that are residing in the main memory and are waiting to execute are kept on a list called the ............

A) job queue

B) ready queue

C) wait queue

D) device queue



8. Which of the following describes the ability of an OS to support multiple, concurrent paths of execution within a single process?

A) Multithreading

B) Multiprocessing

C) Multitasking

D) Multiprogramming



9. Virtual memory is

A) an extremely large main memory

B) an extremely large secondary memory

C) an illusion of extremely large main memory

D) a type of memory used in super computers



10. A thread is a .................... precess.

A) heavy weight

B) multiprocess

C) inter thread

D) light weight






Answers:


1. Operating System means ........................

A) a set of programs which controls computer working.

2. The basic types of OS are ...................

D) batch and interactive

3. The simplest way of deadlock is to ...

C) kill one of the processes

4. Throughput of a system is

A) Number of programs processed by it per unit time

5. Which of the following is not OS layer?

D) Critical Section

6. Round robin scheduling is essentially the preemptive version of ...........

A) first in first out

7. The process that are residing in the main memory and are waiting to execute are kept on a list called the ............

B) ready queue

8. Which of the following describes the ability of an OS to support multiple, concurrent paths of execution within a single process?

A) Multithreading

9. Virtual memory is

C) an illusion of extremely large main memory

10. A thread is a .................... precess.

D) light weight



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List the different types of memory management techniques in OS

List the different types of memory management techniques in OS

2:05 م اضافة تعليق
In uniprogramming system, main memory is divided into two parts, one pare for the operating system (resident monitor, kernel) and one part for the program currently being executed. In multiprogramming system, the 'user' part of the memory must be further subdivided to accommodate multiple processes. The task of subdivision is carried out dynamically by operating system and is known as memory management.

Memory management by OS can be divided into two methods: 

 

# Real Memory Management


In real memory management OS operates the space of the main memory only.

There are two ways of real memory management.

a) Mono Programming System:– Execution of one program at one time. The memory is divided into two parts, one is to save the OS and the other is to save programs.

b) Multi Programming System:– Several simultaneous processes can be executed at the same time. Memory space is shared by several processes. To enable it to run a process should be stored into the memory. When the execution process is completed, it will be taken out from the memory. There are two schemes.

i. Fixed Size Partitioning: Partitioning of memory space into several spaces. One process is started into the memory if there is a memory space that can fit the process.

ii. Variable size partitioning: A process is started if there is memory space that is still empty if there is memory space that is still empty which can fit the process. This method is better and more flexible.

# Virtual Memory Management


Virtual memory is a scheme that is transparent to the application process and allows each process to behave as if it had unlimited main memory at its disposal. To achieve this, the operating system creates for each process a virtual address space on disk. Part of virtual memory is brought into real main memory as needed.

There are three techniques of virtual memory management which are given below:–

i. Paging Method: This method introduced in the 1960's Atlas computer, sets up enough memory space for each process by making the secondary storage as an extension to the main memory. The virtual memory space is provided is divided into several pages with every page having the same size. The main memory is divided into a few framework pages. This page framework is shared with a program in the system at that point.

ii. Segmentation Method: Segmentation method provides a large sized of virtual memory, but require virtual memory which provides multidimensional memory. This form of memory management is known as segmented virtual memory management. Segmentation allows the programmer to view memory as consisting of multiple address spaces or segments. Segments may be of unequal, indeed dynamic size.

iii. Paging and Segmentation Method: In paging and segmentation method both paging and segmentation have their strengths. This virtual memory is multidimensional and provides many segments and each segment has a large volume.

What are the different types of scheduling methods?

What are the different types of scheduling methods?

1:42 م اضافة تعليق

Process scheduling is one way for a processor to handle n processes, by scheduling the execution process. Each process is executed one by one according to prescribed schedule.

The aim of processor scheduling is to assign processes to be executed by the processor or processors over time, in a way that meets system objectives, such as response time, throughput and processor efficiency. In many systems, this scheduling activity is broken down into three separate functions: long, medium and short-term scheduling.

Types of Scheduling 


Long term Scheduling

The long term scheduler determines which programs are admitted to the system for processing. Thus, it controls the degree of multiprogramming. Once admitted a job or user program becomes a process and added to the queue for the short term scheduler. In some systems, a newly created process begins in a swapped-out condition, in which case it is added to the queue for the medium term scheduler.

Medium term scheduling

 Medium term scheduling is a part of the swapping function. The swapping in decision is based on the need to manage the degree of multiprogramming.
 It is the decision to add to the number of processes that are partially of fully in main memory.

Short term scheduling

The short term scheduler is also known as the dispatcher executes must frequently and makes the fine grained decision of which process to execute next.

It is the decision as to which available process will be executed by the processor.

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MCQ of Computer Security with answer set – 2

MCQ of Computer Security with answer set – 2

9:54 ص اضافة تعليق

1. …………….. are used in denial of service attacks, typically against targeted web sites.
A) Worm
B) Zombie
C) Virus
D) Trojan horse

2. Select the correct order for the different phases of virus execution.
i) Propagation phase                      ii) Dormant phase
iii) Execution phase                         iv) Triggering phase
A) i, ii, iii, and iv
B) i, iii, ii and iv
C) ii, i, iv an iii
D) ii, iii, iv and i


3. A ………………… attaches itself to executable files and replicates, when the infected program is executed, by finding other executable files to infect.
A) Stealth virus
B) Polymorphic Virus
C) Parasitic Virus
D) Macro Virus

4. …………………….. is a form of virus explicitly designed to hide itself from detection by antivirus software.
A) Stealth virus
B) Polymorphic Virus
C) Parasitic Virus
D) Macro Virus

5. A …………………….. creates copies during replication that are functionally equivalent but have distinctly different bit patterns.
A) Boot Sector Virus
B) Polymorphic Virus
C) Parasitic Virus
D) Macro Virus

6. A portion of the Polymorphic virus, generally called a …………………….. , creates, a random encryption, key to encrypt the remainder of the virus.
A) mutual engine
B) mutation engine       
C) multiple engine
D) polymorphic engine

7. State whether the following statement is true.
i) A macro virus is platform independent.
ii) Macro viruses infect documents, not executable portions of code.
A) i-only
B) ii-only
C) Both i and ii
D) Non i and ii

8. The type(s) of auto executing macros, in Microsoft word is/are
A) Auto execute
B) Auto macro
C) Command macro
D) All of the above

9. In …………….., the virus places an identical copy of itself into other programs or into certain system areas on the disk.
A) Dormant phase
B) Propagation phase
C) Triggering phase
D) Execution phase

10. A ……………… is a program that secretly takes over another Internet-attached computer and then uses that computer to launch attacks.
A) Worm
B) Zombie
C) Virus
D) Trap doors
Answers:
1.       B) Zombie
2.       C) ii, i, iv an iii
3.       C) Parasitic Virus
4.       A) Stealth virus
5.       B) Polymorphic Virus
6.       B) mutation engine
7.       C) Both i and ii
8.       D) All of the above
9.       B) Propagation phase
10.   B) Zombie


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Solved MCQ of Computer Security set -1

Solved MCQ of Computer Security set -1

12:10 م اضافة تعليق

1. In computer security, ……………………. means that computer system assets can be modified only by authorized parities.
A) Confidentiality
B) Integrity
C) Availability
D) Authenticity

2. In computer security, …………………….. means that the information in a computer system only be accessible for reading by authorized parities.
A) Confidentiality
B) Integrity
C) Availability
D) Authenticity


3. The type of threats on the security of a computer system or network are ……………………..
i) Interruption                   ii) Interception                  iii) Modification
iv) Creation                         v) Fabrication
A) i, ii, iii and iv only
B) ii, iii, iv and v only
C) i, ii, iii and v only
D) All i, ii, iii, iv and v

4. Which of the following is independent malicious program that need not any host program?
A) Trap doors
B) Trojan horse
C) Virus
D) Worm

5. The ……….. is code that recognizes some special sequence of input or is triggered by being run from a certain user ID of by unlikely sequence of events.
A) Trap doors
B) Trojan horse
C) Logic Bomb
D) Virus

6. The …………….. is code embedded in some legitimate program that is set to “explode” when certain conditions are met.
A) Trap doors
B) Trojan horse
C) Logic Bomb
D) Virus

7. Which of the following malicious program do not replicate automatically?
A) Trojan Horse
B) Virus
C) Worm
D) Zombie

8. …………… programs can be used to accomplish functions indirectly that an unauthorized user could not accomplish directly.
A) Zombie
B) Worm
C) Trojan Horses
D) Logic Bomb

9. State whether true of false.
i) A worm mails a copy of itself to other systems.
ii) A worm executes a copy of itself on another system.
A) True, False
B) False, True
C) True, True
D) False, False

10. A ………….. is a program that can infect other programs by modifying them, the modification includes a copy of the virus program, which can go on to infect other programs.
A) Worm
B) Virus
C) Zombie
D) Trap doors
Answers:
1.       B) Integrity
2.       A) Confidentiality
3.       C) i, ii, iii and v only
4.       D) Worm
5.       A) Trap doors
6.       C) Logic Bomb
7.       A) Trojan Horse
8.       C) Trojan Horses
9.       C) True, True
10.   B) Virus


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Solved MCQ of Operating System Set-6

Solved MCQ of Operating System Set-6

12:24 م اضافة تعليق

1. …………. Involves treating main memory as a resource to be allocated to and shared among a number of active processes.
A) Partition management
B) Memory management
C) Disk management
D) All of the above

2. A process that execute only in main memory is referred to as ……………… and that allocated in disk is referred to a …………….
A) virtual memory, true memory
B) virtual memory, real memory
C) real memory, virtual memory
D) imaginary memory, real memory


3. In process scheduling, …………………… determines when new processes are admitted to the system.
A) long term scheduling
B) medium term scheduling
C) short term scheduling
D) none of the above

4. In process scheduling, ………………… determines which ready process will be executed next by processor.
A) long term scheduling
B) medium term scheduling
C) short term scheduling
D) none of the above

5. The sum of the seek time, and the rotational delay is called the ………………..
A) reached time
B) access time
C) arrived time
D) common time

6. The …………….. policy segments the disks request queue into sub queues of the length N.
A) SCAN
B) C-SCAN
C) N-Step SCAN
D) FSCAN

 7. Which of the following are the functions of operating system?
i) recovering from errors                              ii) facilitating input/output
iii) facilitating parallel operation                 iv) sharing hardware among users
v) implementing user interface
A) i, ii, ii, and v only
B) i, ii, iii, and iv only
C) ii, iii, iv and v only
D) All i, ii, iii, iv and v

8. File management function of the operating system includes
i) File creation and deletion                         ii) Disk scheduling
iii) Directory creation                                      iv) Mapping file in secondary storage.
A) i, ii and iii only
B) i, iii and iv only
C) ii, iii and iv only
D) All i, ii, iii and iv

9. The ……………. Determines when a page should be brought into main memory.
A) Fetch policy
B) Placement policy
C) Replacement policy
D) Resident set management

10. With …………………. A page is written out to secondary memory only when it has been selected for replacement.
A) pre-cleaning
B) demand cleaning
C) required cleaning
D) fast cleaning
Answers:
1.       B) Memory management
2.       C) real . virtual memory
3.       A) long term scheduling
4.       C) short term scheduling
5.       B) access time
6.       C) N-Step SCAN
7.       D) All i, ii, iii, iv and v
8.       B) i, iii and iv only
9.       A) Fetch policy
10.   B) demand cleaning

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Solved MCQ of Operating System Set-5

Solved MCQ of Operating System Set-5

6:56 ص اضافة تعليق

1. The unit of dispatching is usually referred to as a …………..
A) Thread
B) Lightweight process
C) Process
D) Both A and B

2. ……………….. is a example of an operating system that support single user process and single thread.
A) UNIX
B) MS-DOS
C) OS/2
D) Windows 2000

3. State true or false.
i) Unix, support multiple user process but only support one thread per process.
ii) A java run time environment is an example of a system of one process with multiple threads.
A) True, False
B) True, True
C) False, True
D) False, False

4. …………… are very effective because a mode switch is not required to switch from one thread to another.
A) Kernel-level threads
B) User-level threads
C) Alterable threads
D) Application level threads

5. …………… is a condition in which there is a set of concurrent processes, only one of which is able to access a given resource or perform a given function at any time.
A) Mutual Exclusion
B) Busy Waiting
C) Deadlock
D) Starvation

6. …………………. Techniques can be used to resolve  conflicts, such as competition for resources, and to synchronize processes so that they can cooperate.
A) Mutual Exclusion
B) Busy Waiting
C) Deadlock
D) Starvation

7. ……………. Can be defined as the permanent blocking of a set of processed that either complete for system resources or communicate with each other.
A) Deadlock
B) Permanent lock
C) Starvation
D) Mutual exclusion

8. The following conditions of policy must be present for a deadlock to be possible.
i) Mutual exclusion                                          ii) Hold and wait
iii) No preemption                                           iv) Circular wait
A) i, ii and iii only
B) ii, iii and iv only
C) i, iii and iv only
D) All i, ii, iii and iv

9. A direct method of deadlock prevention is to prevent the occurrence of …………..
A) Mutual exclusion
B) Hold and wait
C) Circular waits
D) No preemption

 10. State true of false.
i) With paging, each process is divided into relatively small, fixed-size pages.
ii) Segmentation provides for the use of pieces of varying size.
A) True, False
B) True, True
C) False, True
D) False, False

Answers:
1.       D) Both A and B
2.       B) MS-DOS
3.       A) True, False
4.       B) User-level threads
5.       A) Mutual Exclusion
6.       A) Mutual Exclusion
7.       A) Deadlock
8.       D) All i, ii, iii and iv
9.       C) Circular waits
10.   B) True, True

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