650+ Operating System (OS) Solved MCQs

These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Computer Science Engineering (CSE) , Information Technology Engineering (IT) , Bachelor of Science in Computer Science FY (BSc CS) , Bachelor of Computer Applications (BCA) , Bachelor of Science in Computer Science (BSc CS) .

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551.	Which of the following system calls does not return control to the calling point, on termination?
A.	fork
B.	exec
C.	ioctl
D.	longjmp
Answer» B. exec

552.	Which of the following system calls transforms executable binary file into a process?
A.	fork
B.	exec
C.	ioctl
D.	longjmp
Answer» B. exec

553.	Which of the following calls never returns an error?
A.	getpid
B.	fork
C.	ioctl
D.	open
Answer» A. getpid

554.	A fork system call will fail if
A.	the previously executed statement is also a fork call
B.	the limit on the maximum number of processes in the system would be executed
C.	the limit on the minimum number of processes that can be under execution by a single user would be executed
D.	all of the mentioned
Answer» B. the limit on the maximum number of processes in the system would be executed

555.	If a thread invokes the exec system call
A.	only the exec executes as a separate process
B.	the program specified in the parameter to exec will replace the entire process
C.	the exec is ignored as it is invoked by a thread
D.	none of the mentioned
Answer» B. the program specified in the parameter to exec will replace the entire process

556.	If exec is called immediately after forking
A.	the program specified in the parameter to exec will replace the entire process
B.	all the threads will be duplicated
C.	all the threads may be duplicated
D.	none of the mentioned
Answer» A. the program specified in the parameter to exec will replace the entire process

557.	If a process does not call exec after forking
A.	the program specified in the parameter to exec will replace the entire process
B.	all the threads should be duplicated
C.	all the threads should not be duplicated
D.	none of the mentioned
Answer» B. all the threads should be duplicated

558.	What is Thread cancellation?
A.	the task of destroying the thread once its work is done
B.	the task of removing a thread once its work is done
C.	the task of terminating a thread before it has completed
D.	none of the mentioned
Answer» C. the task of terminating a thread before it has completed

559.	When a web page is loading, and the user presses a button on the browser to stop loading the page?
A.	the thread loading the page continues with the loading
B.	the thread loading the page does not stop but continues with another task
C.	the thread loading the page is paused
D.	the thread loading the page is cancelled
Answer» D. the thread loading the page is cancelled

560.	When one thread immediately terminates the target thread, it is called
A.	asynchronous cancellation
B.	systematic cancellation
C.	sudden termination
D.	deferred cancellation
Answer» A. asynchronous cancellation

561.	When the target thread periodically checks if it should terminate and terminates itself in an orderly manner, it is called?
A.	asynchronous cancellation
B.	systematic cancellation
C.	sudden termination
D.	deferred cancellation
Answer» D. deferred cancellation

565.	Signals that occur at the same time, are presented to the process
A.	one at a time, in a particular order
B.	one at a time, in no particular order
C.	all at a time
D.	none of the mentioned
Answer» B. one at a time, in no particular order

566.	Which of the following is not TRUE?
A.	processes may send each other signals
B.	kernel may send signals internally
C.	a field is updated in the signal table when the signal is sent
D.	each signal is maintained by a single bit
Answer» C. a field is updated in the signal table when the signal is sent

568.	The three ways in which a process responds to a signal are
A.	ignoring the signal
B.	handling the signal
C.	performing some default action
D.	all of the mentioned
Answer» D. all of the mentioned

569.	Signals are identified by
A.	signal identifiers
B.	signal handlers
C.	signal actions
D.	none of the mentioned
Answer» A. signal identifiers

562.	Cancelling a thread asynchronously
A.	frees all the resources properly
B.	may not free each resource
C.	spoils the process execution
D.	none of the mentioned
Answer» B. may not free each resource

563.	Cancellation point is the point where
A.	the thread can be cancelled – safely or otherwise doesn’t matter
B.	the thread can be cancelled safely
C.	the whole process can be cancelled safely
D.	none of the mentioned
Answer» B. the thread can be cancelled safely

564.	If multiple threads are concurrently searching through a database and one thread returns the result then the remaining threads must be
A.	continued
B.	cancelled
C.	protected
D.	none of the mentioned
Answer» B. cancelled

567.	Signals of a given type
A.	are queued
B.	are all sent as one
C.	cannot be queued
D.	none of the mentioned
Answer» B. are all sent as one

570.	When a process blocks the receipt of certain signals?
A.	the signals are delivered
B.	the signals are not delivered
C.	the signals are received until they are unblocked
D.	the signals are received by the process once they are delivered
Answer» A. the signals are delivered

571.	The maintains pending and blocked bit vectors in the context of each process.
A.	cpu
B.	memory
C.	process
D.	kernel
Answer» D. kernel

572.	In UNIX, the set of masked signals can be set or cleared using the function.
A.	sigmask
B.	sigmaskproc
C.	sigprocmask
D.	sigproc
Answer» C. sigprocmask

573.	The usefulness of signals as a general inter process communication mechanism is limited because
A.	they do not work between processes
B.	they are user generated
C.	they cannot carry information directly
D.	none of the mentioned
Answer» C. they cannot carry information directly

574.	The usual effect of abnormal termination of a program is
A.	core dump file generation
B.	system crash
C.	program switch
D.	signal destruction
Answer» A. core dump file generation

575.	In most cases, if a process is sent a signal while it is executing a system call
A.	the system call will continue execution and the signal will be ignored completely
B.	the system call is interrupted by the signal, and the signal handler comes in
C.	the signal has no effect until the system call completes
D.	none of the mentioned
Answer» C. the signal has no effect until the system call completes

650+ Operating System (OS) Solved MCQs

Which of the following system calls does not return control to the calling point, on termination?

Which of the following system calls transforms executable binary file into a process?

Which of the following calls never returns an error?

A fork system call will fail if

If a thread invokes the exec system call

If exec is called immediately after forking

If a process does not call exec after forking

What is Thread cancellation?

When a web page is loading, and the user presses a button on the browser to stop loading the page?

When one thread immediately terminates the target thread, it is called

When the target thread periodically checks if it should terminate and terminates itself in an orderly manner, it is called?

Cancelling a thread asynchronously

Cancellation point is the point where

If multiple threads are concurrently searching through a database and one thread returns the result then the remaining threads must be

Signals that occur at the same time, are presented to the process

Which of the following is not TRUE?

Signals of a given type

The three ways in which a process responds to a signal are

Signals are identified by

When a process blocks the receipt of certain signals?

The maintains pending and blocked bit vectors in the context of each process.

In UNIX, the set of masked signals can be set or cleared using the function.

The usefulness of signals as a general inter process communication mechanism is limited because

The usual effect of abnormal termination of a program is

In most cases, if a process is sent a signal while it is executing a system call

A process can never be sure that a signal it has sent

In UNIX, the system call is used to send a signal.

Thread pools are useful when

Instead of starting a new thread for every task to execute concurrently, the task can be passed to a

Each connection arriving at multi threaded servers via network is generally

What is the idea behind thread pools?

If the thread pool contains no available thread

Thread pools help in

The number of the threads in the pool can be decided on factors such as

The swaps processes in and out of the memory.

The address generated by the CPU is referred to as

Operating System maintains the page table for

What is operating system?

In a time-sharing operating system, when the time slot given to a process is completed, the process goes from the running state to the:

In virtual memory, which is not a page replacement algorithm ?

Thrashing the CPU utilization.

Mutual exclusion can be provided by the

A parent process calling system call will be suspended until children processes terminate.

The child process completes execution, but the parent keeps executing, then the child process is known as

When the process issues an I/O request

Which one of the following is the deadlock avoidance algorithm?

File type can be represented by

Which of the following are the two parts of the file name?

Which of the following are forms of malicious attack?

From the following, which is not a common file permission?

576.	A process can never be sure that a signal it has sent
A.	has which identifier
B.	has not been lost
C.	has been sent
D.	all of the mentioned
Answer» B. has not been lost

577.	In UNIX, the system call is used to send a signal.
A.	sig
B.	send
C.	kill
D.	sigsend
Answer» C. kill

578.	Thread pools are useful when
A.	when we need to limit the number of threads running in the application at the same time
B.	when we need to limit the number of threads running in the application as a whole
C.	when we need to arrange the ordering of threads
D.	none of the mentioned
Answer» A. when we need to limit the number of threads running in the application at the same time

579.	Instead of starting a new thread for every task to execute concurrently, the task can be passed to a
A.	process
B.	thread pool
C.	thread queue
D.	none of the mentioned
Answer» B. thread pool

580.	Each connection arriving at multi threaded servers via network is generally
A.	is directly put into the blocking queue
B.	is wrapped as a task and passed on to a thread pool
C.	is kept in a normal queue and then sent to the blocking queue from where it is dequeued
D.	none of the mentioned
Answer» B. is wrapped as a task and passed on to a thread pool

581.	What is the idea behind thread pools?
A.	a number of threads are created at process startup and placed in a pool where they sit and wait for work
B.	when a process begins, a pool of threads is chosen from the many existing and each thread is allotted equal amount of work
C.	all threads in a pool distribute the task equally among themselves
D.	none of the mentioned
Answer» A. a number of threads are created at process startup and placed in a pool where they sit and wait for work

582.	If the thread pool contains no available thread
A.	the server runs a new process
B.	the server goes to another thread pool
C.	the server demands for a new pool creation
D.	the server waits until one becomes free
Answer» D. the server waits until one becomes free

583.	Thread pools help in
A.	servicing multiple requests using one thread
B.	servicing a single request using multiple threads from the pool
C.	faster servicing of requests with an existing thread rather than waiting to create a new thread
D.	none of the mentioned
Answer» C. faster servicing of requests with an existing thread rather than waiting to create a new thread

584.	The number of the threads in the pool can be decided on factors such as
A.	number of cpus in the system
B.	amount of physical memory
C.	expected number of concurrent client requests
D.	all of the mentioned
Answer» D. all of the mentioned

585.	The swaps processes in and out of the memory.
A.	Memory Manager
B.	CPU
C.	CPU Manager
D.	User
Answer» A. Memory Manager