650+ Operating System (OS) Solved MCQs

201.

The FCFS algorithm is particularly troublesome for                          

A. time sharing systems
B. multiprogramming systems
C. multiprocessor systems
D. operating systems
Answer» B. multiprogramming systems
202.

What is ‘Aging’?

A. keeping track of cache contents
B. keeping track of what pages are currently residing in memory
C. keeping track of how many times a given page is referenced
D. increasing the priority of jobs to ensure termination in a finite time
Answer» D. increasing the priority of jobs to ensure termination in a finite time
203.

An SJF algorithm is simply a priority algorithm where the priority is                          

A. the predicted next cpu burst
B. the inverse of the predicted next cpu burst
C. the current cpu burst
D. anything the user wants
Answer» A. the predicted next cpu burst
204.

Which of the following scheduling algorithms gives minimum average waiting time?

A. fcfs
B. sjf
C. round – robin
D. priority
Answer» B. sjf
205.

What is an operating system?

A. collection of programs that manages hardware resources
B. system service provider to the application programs
C. interface between the hardware and application programs
D. all of the mentioned
Answer» D. all of the mentioned
206.

To access the services of operating system, the interface is provided by the                        

A. system calls
B. api
C. library
D. assembly instructions
Answer» A. system calls
207.

Which one of the following is not true?

A. kernel is the program that constitutes the central core of the operating system
B. kernel is the first part of operating system to load into memory during booting
C. kernel is made of various modules which can not be loaded in running operating system
D. kernel remains in the memory during the entire computer session
Answer» C. kernel is made of various modules which can not be loaded in running operating system
208.

Which one of the following error will be handle by the operating system?

A. power failure
B. lack of paper in printer
C. connection failure in the network
D. all of the mentioned
Answer» D. all of the mentioned
209.

What is the main function of the command interpreter?

A. to get and execute the next user-specified command
B. to provide the interface between the api and application program
C. to handle the files in operating system
D. none of the mentioned
Answer» A. to get and execute the next user-specified command
210.

In Operating Systems, which of the following is/are CPU scheduling algorithms?

A. round robin
B. shortest job first
C. priority
D. all of the mentioned
Answer» D. all of the mentioned
211.

If a process fails, most operating system write the error information to a              

A. log file
B. another running process
C. new file
D. none of the mentioned
Answer» A. log file
212.

Which facility dynamically adds probes to a running system, both in user processes and in the kernel?

A. dtrace
B. dlocate
C. dmap
D. dadd
Answer» A. dtrace
213.

Which one of the following is not a real time operating system?

A. vxworks
B. qnx
C. rtlinux
D. palm os
Answer» D. palm os
214.

The OS X has                          

A. monolithic kernel
B. hybrid kernel
C. microkernel
D. monolithic kernel with modules
Answer» B. hybrid kernel
215.

The systems which allow only one process execution at a time, are called                      

A. uniprogramming systems
B. uniprocessing systems
C. unitasking systems
D. none of the mentioned
Answer» B. uniprocessing systems
216.

In operating system, each process has its own                      

A. address space and global variables
B. open files
C. pending alarms, signals and signal handlers
D. all of the mentioned
Answer» D. all of the mentioned
217.

In Unix, Which system call creates the new process?

A. fork
B. create
C. new
D. none of the mentioned
Answer» A. fork
218.

What is interprocess communication?

A. communication within the process
B. communication between two process
C. communication between two threads of same process
D. none of the mentioned
Answer» B. communication between two process
219.

Which system call can be used by a parent process to determine the termination of child process?

A. wait
B. exit
C. fork
D. get
Answer» A. wait
220.

The address of the next instruction to be executed by the current process is provided by the                      

A. cpu registers
B. program counter
C. process stack
D. pipe
Answer» B. program counter
221.

The number of processes completed per unit time is known as                      

A. output
B. throughput
C. efficiency
D. capacity
Answer» B. throughput
222.

Which of the following is not the state of a process?

A. new
B. old
C. waiting
D. running
Answer» B. old
223.

What is a Process Control Block?

A. process type variable
B. data structure
C. a secondary storage section
D. a block in memory
Answer» B. data structure
224.

The entry of all the PCBs of the current processes is in                      

A. process register
B. program counter
C. process table
D. process unit
Answer» C. process table
225.

What is the degree of multiprogramming?

A. the number of processes executed per unit time
B. the number of processes in the ready queue
C. the number of processes in the i/o queue
D. the number of processes in memory
Answer» D. the number of processes in memory
226.

A single thread of control allows the process to perform                      

A. only one task at a time
B. multiple tasks at a time
C. only two tasks at a time
D. all of the mentioned
Answer» A. only one task at a time
227.

What is the objective of multiprogramming?

A. have a process running at all time
B. have multiple programs waiting in a queue ready to run
C. to increase cpu utilization
D. none of the mentioned
Answer» C. to increase cpu utilization
228.

Which of the following do not belong to queues for processes?

A. job queue
B. pcb queue
C. device queue
D. ready queue
Answer» B. pcb queue
229.

When the process issues an I/O request

A. it is placed in an i/o queue
B. it is placed in a waiting queue
C. it is placed in the ready queue
D. it is placed in the job queue
Answer» A. it is placed in an i/o queue
230.

What will happen when a process terminates?

A. it is removed from all queues
B. it is removed from all, but the job queue
C. its process control block is de-allocated
D. its process control block is never de- allocated
Answer» A. it is removed from all queues
231.

What is a long-term scheduler?

A. it selects processes which have to be brought into the ready queue
B. it selects processes which have to be executed next and allocates cpu
C. it selects processes which heave to remove from memory by swapping
D. none of the mentioned
Answer» A. it selects processes which have to be brought into the ready queue
232.

If all processes I/O bound, the ready queue will almost always be              and the Short term Scheduler will have a              to do.

A. full, little
B. full, lot
C. empty, little
D. empty, lot
Answer» C. empty, little
233.

What is a medium-term scheduler?

A. it selects which process has to be brought into the ready queue
B. it selects which process has to be executed next and allocates cpu
C. it selects which process to remove from memory by swapping
D. none of the mentioned
Answer» C. it selects which process to remove from memory by swapping
234.

What is a short-term scheduler?                      

A. it selects which process has to be brought into the ready queue
B. it selects which process has to be executed next and allocates cpu
C. it selects which process to remove from memory by swapping
D. none of the mentioned
Answer» B. it selects which process has to be executed next and allocates cpu
235.

The primary distinction between the short term scheduler and the long term scheduler is

A. the length of their queues
B. the type of processes they schedule
C. the frequency of their execution
D. none of the mentioned
Answer» C. the frequency of their execution
236.

In a multiprogramming environment

A. the processor executes more than one process at a time
B. the programs are developed by more than one person
C. more than one process resides in the memory
D. a single user can execute many programs at the same time
Answer» C. more than one process resides in the memory
237.

The context of a process in the PCB of a process does not contain                      

A. the value of the cpu registers
B. the process state
C. memory-management information
D. context switch time
Answer» D. context switch time
238.

Which of the following need not necessarily be saved on a context switch between processes?

A. general purpose registers
B. translation lookaside buffer
C. program counter
D. all of the mentioned
Answer» B. translation lookaside buffer
239.

Which of the following does not interrupt a running process?

A. a device
B. timer
C. scheduler process
D. power failure
Answer» C. scheduler process
240.

Which process can be affected by other processes executing in the system?

A. cooperating process
B. child process
C. parent process
D. init process
Answer» A. cooperating process
241.

When several processes access the same data concurrently and the outcome of the execution depends on the particular order in which the access takes place, is called?

A. dynamic condition
B. race condition
C. essential condition
D. critical condition
Answer» B. race condition
242.

If a process is executing in its critical section, then no other processes can be executing in their critical section. This condition is called?

A. mutual exclusion
B. critical exclusion
C. synchronous exclusion
D. asynchronous exclusion
Answer» A. mutual exclusion
243.

Which one of the following is a synchronization tool?

A. thread
B. pipe
C. semaphore
D. socket
Answer» C. semaphore
244.

A semaphore is a shared integer variable

A. that can not drop below zero
B. that can not be more than zero
C. that can not drop below one
D. that can not be more than one
Answer» A. that can not drop below zero
245.

Mutual exclusion can be provided by the

A. mutex locks
B. binary semaphores
C. both mutex locks and binary semaphores
D. none of the mentioned
Answer» C. both mutex locks and binary semaphores
246.

When high priority task is indirectly preempted by medium priority task effectively inverting the relative priority of the two tasks, the scenario is called

A. priority inversion
B. priority removal
C. priority exchange
D. priority modification
Answer» A. priority inversion
247.

Process synchronization can be done on

A. hardware level
B. software level
C. both hardware and software level
D. none of the mentioned
Answer» C. both hardware and software level
248.

A monitor is a module that encapsulates

A. shared data structures
B. procedures that operate on shared data structure
C. synchronization between concurrent procedure invocation
D. all of the mentioned
Answer» D. all of the mentioned
249.

To enable a process to wait within the monitor                      

A. a condition variable must be declared as condition
B. condition variables must be used as boolean objects
C. semaphore must be used
D. all of the mentioned
Answer» A. a condition variable must be declared as condition
250.

Restricting the child process to a subset of the parent’s resources prevents any process from                      

A. overloading the system by using a lot of secondary storage
B. under-loading the system by very less cpu utilization
C. overloading the system by creating a lot of sub-processes
D. crashing the system by utilizing multiple resources
Answer» C. overloading the system by creating a lot of sub-processes
251.

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

A. wait
B. fork
C. exit
D. exec
Answer» A. wait
252.

Cascading termination refers to termination of all child processes before the parent terminates              

A. normally
B. abnormally
C. normally or abnormally
D. none of the mentioned
Answer» A. normally
253.

In UNIX, each process is identified by its

A. process control block
B. device queue
C. process identifier
D. none of the mentioned
Answer» C. process identifier
254.

The child process can                      

A. be a duplicate of the parent process
B. never be a duplicate of the parent process
C. cannot have another program loaded into it
D. never have another program loaded into it
Answer» A. be a duplicate of the parent process
255.

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

A. orphan
B. zombie
C. body
D. dead
Answer» B. zombie
256.

What is Inter process communication?

A. allows processes to communicate and synchronize their actions when using the same address space
B. allows processes to communicate and synchronize their actions without using the same address space
C. allows the processes to only synchronize their actions without communication
D. none of the mentioned
Answer» B. allows processes to communicate and synchronize their actions without using the same address space
257.

Message passing system allows processes to                      

A. communicate with one another without resorting to shared data
B. communicate with one another by resorting to shared data
C. share data
D. name the recipient or sender of the message
Answer» A. communicate with one another without resorting to shared data
258.

Which of the following two operations are provided by the IPC facility?

A. write & delete message
B. delete & receive message
C. send & delete message
D. receive & send message
Answer» D. receive & send message
259.

Messages sent by a process                      

A. have to be of a fixed size
B. have to be a variable size
C. can be fixed or variable sized
D. none of the mentioned
Answer» C. can be fixed or variable sized
260.

The link between two processes P and Q to send and receive messages is called

A. communication link
B. message-passing link
C. synchronization link
D. all of the mentioned
Answer» A. communication link
261.

Which of the following are TRUE for direct communication?

A. a communication link can be associated with n number of process(n = max. number of processes supported by system)
B. a communication link can be associated with exactly two processes
C. exactly n/2 links exist between each pair of processes(n = max. number of processes supported by system)
D. exactly two link exists between each pair of processes
Answer» B. a communication link can be associated with exactly two processes
262.

In indirect communication between

A. there is another process r to handle and pass on the messages between p and q
B. there is another machine between the two processes to help communication
C. there is a mailbox to help communication between p and q
D. none of the mentioned
Answer» C. there is a mailbox to help communication between p and q
263.

In the non blocking send                      

A. the sending process keeps sending until the message is received
B. the sending process sends the message and resumes operation
C. the sending process keeps sending until it receives a message
D. none of the mentioned
Answer» B. the sending process sends the message and resumes operation
264.

In the Zero capacity queue                      

A. the queue can store at least one message
B. the sender blocks until the receiver receives the message
C. the sender keeps sending and the messages don’t wait in the queue
D. none of the mentioned
Answer» B. the sender blocks until the receiver receives the message
265.

The Zero Capacity queue                      

A. is referred to as a message system with buffering
B. is referred to as a message system with no buffering
C. is referred to as a link
D. none of the mentioned
Answer» B. is referred to as a message system with no buffering
266.

Concurrent access to shared data may result in                          

A. data consistency
B. data insecurity
C. data inconsistency
D. none of the mentioned
Answer» C. data inconsistency
267.

A situation where several processes access and manipulate the same data concurrently and the outcome of the execution depends on the particular order in which access takes place is called                          

A. data consistency
B. race condition
C. aging
D. starvation
Answer» B. race condition
268.

The segment of code in which the process may change common variables, update tables, write into files is known as                          

A. program
B. critical section
C. non – critical section
D. synchronizing
Answer» B. critical section
269.

Which of the following conditions must be satisfied to solve the critical section problem?

A. mutual exclusion
B. progress
C. bounded waiting
D. all of the mentioned
Answer» D. all of the mentioned
270.

Mutual exclusion implies that

A. if a process is executing in its critical section, then no other process must be executing in their critical sections
B. if a process is executing in its critical section, then other processes must be executing in their critical sections
C. if a process is executing in its critical section, then all the resources of the system must be blocked until it finishes execution
D. none of the mentioned
Answer» A. if a process is executing in its critical section, then no other process must be executing in their critical sections
271.

Bounded waiting implies that there exists a bound on the number of times a process is allowed to enter its critical section

A. after a process has made a request to enter its critical section and before the request is granted
B. when another process is in its critical section
C. before a process has made a request to enter its critical section
D. none of the mentioned
Answer» A. after a process has made a request to enter its critical section and before the request is granted
272.

A minimum of            variable(s) is/are required to be shared between processes to solve the critical section problem.

A. one
B. two
C. three
D. four
Answer» B. two
273.

In the bakery algorithm to solve the critical section problem                          

A. each process is put into a queue and picked up in an ordered manner
B. each process receives a number (may or may not be unique) and the one with the lowest number is served next
C. each process gets a unique number and the one with the highest number is served next
D. each process gets a unique number and the one with the lowest number is served next
Answer» B. each process receives a number (may or may not be unique) and the one with the lowest number is served next
274.

An un-interruptible unit is known as

A. single
B. atomic
C. static
D. none of the mentioned
Answer» B. atomic
275.

TestAndSet instruction is executed

A. after a particular process
B. periodically
C. atomically
D. none of the mentioned
Answer» C. atomically
276.

Semaphore is a/an                to solve the critical section problem.

A. hardware for a system
B. special program for a system
C. integer variable
D. none of the mentioned
Answer» C. integer variable
277.

What are the two atomic operations permissible on semaphores?

A. wait
B. stop
C. hold
D. none of the mentioned
Answer» A. wait
278.

What are Spinlocks?

A. cpu cycles wasting locks over critical sections of programs
B. locks that avoid time wastage in context switches
C. locks that work better on multiprocessor systems
D. all of the mentioned
Answer» D. all of the mentioned
279.

What is the main disadvantage of spinlocks?

A. they are not sufficient for many process
B. they require busy waiting
C. they are unreliable sometimes
D. they are too complex for programmers
Answer» B. they require busy waiting
280.

The wait operation of the semaphore basically works on the basic                system call.

A. stop()
B. block()
C. hold()
D. wait()
Answer» B. block()
281.

The signal operation of the semaphore basically works on the basic                system call.

A. continue()
B. wakeup()
C. getup()
D. start()
Answer» B. wakeup()
282.

If the semaphore value is negative

A. its magnitude is the number of processes waiting on that semaphore
B. it is invalid
C. no operation can be further performed on it until the signal operation is performed on it
D. none of the mentioned
Answer» A. its magnitude is the number of processes waiting on that semaphore
283.

The code that changes the value of the semaphore is                          

A. remainder section code
B. non – critical section code
C. critical section code
D. none of the mentioned
Answer» C. critical section code
284.

What will happen if a non-recursive mutex is locked more than once?

A. starvation
B. deadlock
C. aging
D. signaling
Answer» B. deadlock
285.

What is a semaphore?

A. is a binary mutex
B. must be accessed from only one process
C. can be accessed from multiple processes
D. none of the mentioned
Answer» C. can be accessed from multiple processes
286.

What are the two kinds of semaphores?

A. mutex & counting
B. binary & counting
C. counting & decimal
D. decimal & binary
Answer» B. binary & counting
287.

What is a mutex?

A. is a binary mutex
B. must be accessed from only one process
C. can be accessed from multiple processes
D. none of the mentioned
Answer» B. must be accessed from only one process
288.

A binary semaphore is a semaphore with integer values

A. 1
B. -1
C. 0.8
D. 0.5
Answer» A. 1
289.

Semaphores are mostly used to implement

A. system calls
B. ipc mechanisms
C. system protection
D. none of the mentioned
Answer» B. ipc mechanisms
290.

The bounded buffer problem is also known as                          

A. readers – writers problem
B. dining – philosophers problem
C. producer – consumer problem
D. none of the mentioned
Answer» C. producer – consumer problem
291.

In the bounded buffer problem, there are the empty and full semaphores that

A. count the number of empty and full buffers
B. count the number of empty and full memory spaces
C. count the number of empty and full queues
D. none of the mentioned
Answer» A. count the number of empty and full buffers
292.

To ensure difficulties do not arise in the readers – writers problem                are given exclusive access to the shared object.

A. readers
B. writers
C. readers and writers
D. none of the mentioned
Answer» B. writers
293.

The dining – philosophers problem will occur in case of                          

A. 5 philosophers and 5 chopsticks
B. 4 philosophers and 5 chopsticks
C. 3 philosophers and 5 chopsticks
D. 6 philosophers and 5 chopsticks
Answer» A. 5 philosophers and 5 chopsticks
294.

A deadlock free solution to the dining philosophers problem                          

A. necessarily eliminates the possibility of starvation
B. does not necessarily eliminate the possibility of starvation
C. eliminates any possibility of any kind of problem further
D. none of the mentioned
Answer» B. does not necessarily eliminate the possibility of starvation
295.

A monitor is a type of                          

A. semaphore
B. low level synchronization construct
C. high level synchronization construct
D. none of the mentioned
Answer» C. high level synchronization construct
296.

A monitor is characterized by

A. a set of programmer defined operators
B. an identifier
C. the number of variables in it
D. all of the mentioned
Answer» A. a set of programmer defined operators
297.

A procedure defined within a                   can access only those variables declared locally within the                and its formal parameters.

A. process, semaphore
B. process, monitor
C. semaphore, semaphore
D. monitor, monitor
Answer» D. monitor, monitor
298.

If no process is suspended, the signal operation                          

A. puts the system into a deadlock state
B. suspends some default process execution
C. nothing happens
D. the output is unpredictable
Answer» C. nothing happens
299.

A collection of instructions that performs a single logical function is called

A. only one process can be active at a time within the monitor
B. n number of processes can be active at a time within the monitor (n being greater than 1)
C. the queue has only one process in it at a time
D. all of the mentioned
Answer» A. only one process can be active at a time within the monitor
300.

What are the operations that can be invoked on a condition variable?

A. wait & signal
B. hold & wait
C. signal & hold
D. continue & signal
Answer» A. wait & signal
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