650+ Operating System (OS) Solved MCQs

301.

Which is the process of invoking the wait

A. transaction
B. operation
C. function
D. all of the mentioned
Answer» A. transaction
302.

Write ahead logging is a way

A. to ensure atomicity
B. to keep data consistent
C. that records data on stable storage
D. all of the mentioned
Answer» D. all of the mentioned
303.

The system periodically performs checkpoints that consists of the following operation(s)                          

A. putting all the log records currently in main memory onto stable storage
B. putting all modified data residing in main memory onto stable storage
C. putting a log record onto stable storage
D. all of the mentioned
Answer» D. all of the mentioned
304.

A locking protocol is one that

A. governs how locks are acquired
B. governs how locks are released
C. governs how locks are acquired and released
D. none of the mentioned
Answer» C. governs how locks are acquired and released
305.

The two phase locking protocol consists of                          

A. growing & shrinking phase
B. shrinking & creation phase
C. creation & growing phase
D. destruction & creation phase
Answer» A. growing & shrinking phase
306.

The growing phase is a phase in which?

A. a transaction may obtain locks, but does not release any
B. a transaction may obtain locks, and releases a few or all of them
C. a transaction may release locks, but does not obtain any new locks
D. a transaction may release locks, and does obtain new locks
Answer» A. a transaction may obtain locks, but does not release any
307.

What is a reusable resource?

A. that can be used by one process at a time and is not depleted by that use
B. that can be used by more than one process at a time
C. that can be shared between various threads
D. none of the mentioned
Answer» A. that can be used by one process at a time and is not depleted by that use
308.

Which of the following condition is required for a deadlock to be possible?

A. mutual exclusion
B. a process may hold allocated resources while awaiting assignment of other resources
C. no resource can be forcibly removed from a process holding it
D. all of the mentioned
Answer» D. all of the mentioned
309.

Which of the following concurrency control protocols ensure both conflict serializability and freedom from deadlock?

A. the system can allocate resources to each process in some order and still avoid a deadlock
B. there exist a safe sequence
C. all of the mentioned
D. none of the mentioned
Answer» A. the system can allocate resources to each process in some order and still avoid a deadlock
310.

The circular wait condition can be prevented by                          

A. defining a linear ordering of resource types
B. using thread
C. using pipes
D. all of the mentioned
Answer» A. defining a linear ordering of resource types
311.

Which one of the following is the deadlock avoidance algorithm?

A. banker’s algorithm
B. round-robin algorithm
C. elevator algorithm
D. karn’s algorithm
Answer» A. banker’s algorithm
312.

What is the drawback of banker’s algorithm?

A. in advance processes rarely know how much resource they will need
B. the number of processes changes as time progresses
C. resource once available can disappear
D. all of the mentioned
Answer» D. all of the mentioned
313.

For an effective operating system, when to check for deadlock?

A. every time a resource request is made
B. at fixed time intervals
C. every time a resource request is made at fixed time intervals
D. none of the mentioned
Answer» C. every time a resource request is made at fixed time intervals
314.

A problem encountered in multitasking when a process is perpetually denied necessary resources is called                          

A. deadlock
B. starvation
C. inversion
D. aging
Answer» B. starvation
315.

Which one of the following is a visual ( mathematical ) way to determine the deadlock occurrence?

A. resource allocation graph
B. starvation graph
C. inversion graph
D. none of the mentioned
Answer» A. resource allocation graph
316.

To avoid deadlock                          

A. there must be a fixed number of resources to allocate
B. resource allocation must be done only once
C. all deadlocked processes must be aborted
D. inversion technique can be used
Answer» A. there must be a fixed number of resources to allocate
317.

The number of resources requested by a process                          

A. must always be less than the total number of resources available in the system
B. must always be equal to the total number of resources available in the system
C. must not exceed the total number of resources available in the system
D. must exceed the total number of resources available in the system
Answer» C. must not exceed the total number of resources available in the system
318.

The request and release of resources are

A. command line statements
B. interrupts
C. system calls
D. special programs
Answer» C. system calls
319.

For a deadlock to arise, which of the following conditions must hold simultaneously?

A. mutual exclusion
B. no preemption
C. hold and wait
D. all of the mentioned
Answer» D. all of the mentioned
320.

For non sharable resources like a printer, mutual exclusion                          

A. must exist
B. must not exist
C. may exist
D. none of the mentioned
Answer» A. must exist
321.

The disadvantage of a process being allocated all its resources before beginning its execution is                          

A. low cpu utilization
B. low resource utilization
C. very high resource utilization
D. none of the mentioned
Answer» B. low resource utilization
322.

Each request requires that the system consider the                            to decide whether the current request can be satisfied or must wait to avoid a future possible deadlock.

A. resources currently available
B. processes that have previously been in the system
C. resources currently allocated to each process
D. future requests and releases of each process
Answer» A. resources currently available
323.

A deadlock avoidance algorithm dynamically examines the                      to ensure that a circular wait condition can never exist.

A. resource allocation state
B. system storage state
C. operating system
D. resources
Answer» A. resource allocation state
324.

A state is safe, if                          

A. the system does not crash due to deadlock occurrence
B. the system can allocate resources to each process in some order and still avoid a deadlock
C. the state keeps the system protected and safe
D. all of the mentioned
Answer» B. the system can allocate resources to each process in some order and still avoid a deadlock
325.

A system is in a safe state only if there exists a                          

A. safe allocation
B. safe resource
C. safe sequence
D. all of the mentioned
Answer» C. safe sequence
326.

All unsafe states are                          

A. deadlocks
B. not deadlocks
C. fatal
D. none of the mentioned
Answer» B. not deadlocks
327.

If no cycle exists in the resource allocation graph                          

A. then the system will not be in a safe state
B. then the system will be in a safe state
C. all of the mentioned
D. none of the mentioned
Answer» B. then the system will be in a safe state
328.

The resource allocation graph is not applicable to a resource allocation system

A. with multiple instances of each resource type
B. with a single instance of each resource type
C. single & multiple instances of each resource type
D. none of the mentioned
Answer» A. with multiple instances of each resource type
329.

The data structures available in the Banker’s algorithm are                          

A. available
B. need
C. allocation
D. all of the mentioned
Answer» D. all of the mentioned
330.

The content of the matrix Need is

A. allocation – available
B. max – available
C. max – allocation
D. allocation – max
Answer» C. max – allocation
331.

The wait-for graph is a deadlock detection algorithm that is applicable when

A. all resources have a single instance
B. all resources have multiple instances
C. all resources have a single 7 multiple instances
D. all of the mentioned
Answer» A. all resources have a single instance
332.

An edge from process Pi to Pj in a wait for graph indicates that                          

A. pi is waiting for pj to release a resource that pi needs
B. pj is waiting for pi to release a resource that pj needs
C. pi is waiting for pj to leave the system
D. pj is waiting for pi to leave the system
Answer» A. pi is waiting for pj to release a resource that pi needs
333.

If the wait for graph contains a cycle

A. then a deadlock does not exist
B. then a deadlock exists
C. then the system is in a safe state
D. either deadlock exists or system is in a safe state
Answer» B. then a deadlock exists
334.

If deadlocks occur frequently, the detection algorithm must be invoked                  

A. rarely
B. frequently
C. rarely & frequently
D. none of the mentioned
Answer» B. frequently
335.

What is the disadvantage of invoking the detection algorithm for every request?

A. overhead of the detection algorithm due to consumption of memory
B. excessive time consumed in the request to be allocated memory
C. considerable overhead in computation time
D. all of the mentioned
Answer» C. considerable overhead in computation time
336.

A deadlock eventually cripples system throughput and will cause the CPU utilization to              

A. increase
B. drop
C. stay still
D. none of the mentioned
Answer» B. drop
337.

Every time a request for allocation cannot be granted immediately, the detection algorithm is invoked. This will help identify

A. the set of processes that have been deadlocked
B. the set of processes in the deadlock queue
C. the specific process that caused the deadlock
D. all of the mentioned
Answer» A. the set of processes that have been deadlocked
338.

A computer system has 6 tape drives, with ‘n’ processes competing for them. Each process may need 3 tape drives. The maximum value of ‘n’ for which the system is guaranteed to be deadlock free is?

A. 2
B. 3
C. 4
D. 1
Answer» A. 2
339.

A system has 3 processes sharing 4 resources. If each process needs a maximum of 2 units then, deadlock                          

A. can never occur
B. may occur
C. has to occur
D. none of the mentioned
Answer» A. can never occur
340.

‘m’ processes share ‘n’ resources of the same type. The maximum need of each process doesn’t exceed ‘n’ and the sum of all their maximum needs is always less than m+n. In this setup, deadlock                          

A. can never occur
B. may occur
C. has to occur
D. none of the mentioned
Answer» A. can never occur
341.

A deadlock can be broken by

A. abort one or more processes to break the circular wait
B. abort all the process in the system
C. preempt all resources from all processes
D. none of the mentioned
Answer» A. abort one or more processes to break the circular wait
342.

The two ways of aborting processes and eliminating deadlocks are                          

A. abort all deadlocked processes
B. abort all processes
C. abort one process at a time until the deadlock cycle is eliminated
D. all of the mentioned
Answer» C. abort one process at a time until the deadlock cycle is eliminated
343.

Those processes should be aborted on occurrence of a deadlock, the termination of which?

A. is more time consuming
B. incurs minimum cost
C. safety is not hampered
D. all of the mentioned
Answer» B. incurs minimum cost
344.

The process to be aborted is chosen on the basis of the following factors?

A. priority of the process
B. process is interactive or batch
C. how long the process has computed
D. all of the mentioned
Answer» D. all of the mentioned
345.

Cost factors for process termination include                          

A. number of resources the deadlock process is not holding
B. cpu utilization at the time of deadlock
C. amount of time a deadlocked process has thus far consumed during its execution
D. all of the mentioned
Answer» C. amount of time a deadlocked process has thus far consumed during its execution
346.

If we preempt a resource from a process, the process cannot continue with its normal execution and it must be                          

A. aborted
B. rolled back
C. terminated
D. queued
Answer» B. rolled back
347.

To                to a safe state, the system needs to keep more information about the states of processes.

A. abort the process
B. roll back the process
C. queue the process
D. none of the mentioned
Answer» B. roll back the process
348.

If the resources are always preempted from the same process                      can occur.

A. deadlock
B. system crash
C. aging
D. starvation
Answer» D. starvation
349.

What is the solution to starvation?

A. the number of rollbacks must be included in the cost factor
B. the number of resources must be included in resource preemption
C. resource preemption be done instead
D. all of the mentioned
Answer» A. the number of rollbacks must be included in the cost factor
350.

What is Address Binding?

A. going to an address in memory
B. locating an address with the help of another address
C. binding two addresses together to form a new address in a different memory space
D. a mapping from one address space to another
Answer» D. a mapping from one address space to another
351.

Binding of instructions and data to memory addresses can be done at                          

A. compile time
B. load time
C. execution time
D. all of the mentioned
Answer» D. all of the mentioned
352.

If the process can be moved during its execution from one memory segment to another, then binding must be                          

A. delayed until run time
B. preponed to compile time
C. preponed to load time
D. none of the mentioned
Answer» A. delayed until run time
353.

What is Dynamic loading?

A. loading multiple routines dynamically
B. loading a routine only when it is called
C. loading multiple routines randomly
D. none of the mentioned
Answer» B. loading a routine only when it is called
354.

What is the advantage of dynamic loading?

A. a used routine is used multiple times
B. an unused routine is never loaded
C. cpu utilization increases
D. all of the mentioned
Answer» B. an unused routine is never loaded
355.

The idea of overlays is to                          

A. data that are needed at any given time
B. enable a process to be larger than the amount of memory allocated to it
C. keep in memory only those instructions
D. all of the mentioned
Answer» D. all of the mentioned
356.

The                        must design and program the overlay structure.

A. programmer
B. system architect
C. system designer
D. none of the mentioned
Answer» A. programmer
357.

The                        swaps processes in and out of the memory.

A. memory manager
B. cpu
C. cpu manager
D. user
Answer» A. memory manager
358.

If binding is done at assembly or load time, then the process            be moved to different locations after being swapped out and in again.

A. can
B. must
C. can never
D. may
Answer» C. can never
359.

In a system that does not support swapping                          

A. the compiler normally binds symbolic addresses (variables) to relocatable addresses
B. the compiler normally binds symbolic addresses to physical addresses
C. the loader binds relocatable addresses to physical addresses
D. binding of symbolic addresses to physical addresses normally takes place during execution
Answer» A. the compiler normally binds symbolic addresses (variables) to relocatable addresses
360.

The address generated by the CPU is referred to as                          

A. physical address
B. logical address
C. neither physical nor logical
D. none of the mentioned
Answer» B. logical address
361.

The address loaded into the memory address register of the memory is referred to as                          

A. physical address
B. logical address
C. neither physical nor logical
D. none of the mentioned
Answer» A. physical address
362.

The run time mapping from virtual to physical addresses is done by a hardware device called the                          

A. virtual to physical mapper
B. memory management unit
C. memory mapping unit
D. none of the mentioned
Answer» B. memory management unit
363.

The size of a process is limited to the size of                          

A. physical memory
B. external storage
C. secondary storage
D. none of the mentioned
Answer» A. physical memory
364.

If execution time binding is being used, then a process              be swapped to a different memory space.

A. has to be
B. can never
C. must
D. may
Answer» D. may
365.

Swapping requires a                    

A. motherboard
B. keyboard
C. monitor
D. backing store
Answer» D. backing store
366.

The backing store is generally a

A. fast disk
B. disk large enough to accommodate copies of all memory images for all users
C. disk to provide direct access to the memory images
D. all of the mentioned
Answer» D. all of the mentioned
367.

The                  consists of all processes whose memory images are in the backing store or in memory and are ready to run.

A. wait queue
B. ready queue
C. cpu
D. secondary storage
Answer» B. ready queue
368.

The                    time in a swap out of a running process and swap in of a new process into the memory is very high.

A. context – switch
B. waiting
C. execution
D. all of the mentioned
Answer» A. context – switch
369.

Swapping                be done when a process has pending I/O, or has to execute I/O operations only into operating system buffers.

A. must
B. can
C. must never
D. maybe
Answer» C. must never
370.

Swap space is allocated                          

A. as a chunk of disk
B. separate from a file system
C. into a file system
D. all of the mentioned
Answer» A. as a chunk of disk
371.

CPU fetches the instruction from memory according to the value of                          

A. program counter
B. status register
C. instruction register
D. program status word
Answer» A. program counter
372.

A memory buffer used to accommodate a speed differential is called                          

A. stack pointer
B. cache
C. accumulator
D. disk buffer
Answer» B. cache
373.

Which one of the following is the address generated by CPU?

A. physical address
B. absolute address
C. logical address
D. none of the mentioned
Answer» C. logical address
374.

Run time mapping from virtual to physical address is done by                          

A. memory management unit
B. cpu
C. pci
D. none of the mentioned
Answer» A. memory management unit
375.

Memory management technique in which system stores and retrieves data from secondary storage for use in main memory is called?

A. fragmentation
B. paging
C. mapping
D. none of the mentioned
Answer» B. paging
376.

The address of a page table in memory is pointed by                          

A. stack pointer
B. page table base register
C. page register
D. program counter
Answer» B. page table base register
377.

Program always deals with                          

A. logical address
B. absolute address
C. physical address
D. relative address
Answer» A. logical address
378.

The page table contains                          

A. base address of each page in physical memory
B. page offset
C. page size
D. none of the mentioned
Answer» A. base address of each page in physical memory
379.

What is compaction?

A. a technique for overcoming internal fragmentation
B. a paging technique
C. a technique for overcoming external fragmentation
D. a technique for overcoming fatal error
Answer» C. a technique for overcoming external fragmentation
380.

Operating System maintains the page table for                          

A. each process
B. each thread
C. each instruction
D. each address
Answer» A. each process
381.

The main memory accommodates

A. operating system
B. cpu
C. user processes
D. all of the mentioned
Answer» A. operating system
382.

What is the operating system?

A. in the low memory
B. in the high memory
C. either low or high memory (depending on the location of interrupt vector)
D. none of the mentioned
Answer» C. either low or high memory (depending on the location of interrupt vector)
383.

In contiguous memory allocation

A. each process is contained in a single contiguous section of memory
B. all processes are contained in a single contiguous section of memory
C. the memory space is contiguous
D. none of the mentioned
Answer» A. each process is contained in a single contiguous section of memory
384.

The relocation register helps in

A. providing more address space to processes
B. a different address space to processes
C. to protect the address spaces of processes
D. none of the mentioned
Answer» C. to protect the address spaces of processes
385.

The operating system and the other processes are protected from being modified by an already running process because

A. they are in different memory spaces
B. they are in different logical addresses
C. they have a protection algorithm
D. every address generated by the cpu is being checked against the relocation and limit registers
Answer» D. every address generated by the cpu is being checked against the relocation and limit registers
386.

Transient operating system code is code that                          

A. is not easily accessible
B. comes and goes as needed
C. stays in the memory always
D. never enters the memory space
Answer» B. comes and goes as needed
387.

Using transient code,                the size of the operating system during program execution.

A. increases
B. decreases
C. changes
D. maintains
Answer» C. changes
388.

In fixed size partition, the degree of multiprogramming is bounded by

A. the number of partitions
B. the cpu utilization
C. the memory size
D. all of the mentioned
Answer» A. the number of partitions
389.

The first fit, best fit and worst fit are strategies to select a              

A. process from a queue to put in memory
B. processor to run the next process
C. free hole from a set of available holes
D. all of the mentioned
Answer» C. free hole from a set of available holes
390.

In internal fragmentation, memory is internal to a partition and                          

A. is being used
B. is not being used
C. is always used
D. none of the mentioned
Answer» B. is not being used
391.

A solution to the problem of external fragmentation is                          

A. compaction
B. larger memory space
C. smaller memory space
D. none of the mentioned
Answer» A. compaction
392.

Another solution to the problem of external fragmentation problem is to                          

A. permit the logical address space of a process to be noncontiguous
B. permit smaller processes to be allocated memory at last
C. permit larger processes to be allocated memory at last
D. all of the mentioned
Answer» A. permit the logical address space of a process to be noncontiguous
393.

If relocation is static and is done at assembly or load time, compaction

A. cannot be done
B. must be done
C. must not be done
D. can be done
Answer» A. cannot be done
394.

The disadvantage of moving all process to one end of memory and all holes to the other direction, producing one large hole of available memory is                          

A. the cost incurred
B. the memory used
C. the cpu used
D. all of the mentioned
Answer» A. the cost incurred
395.

External fragmentation will not occur when?

A. first fit is used
B. best fit is used
C. worst fit is used
D. no matter which algorithm is used, it will always occur
Answer» D. no matter which algorithm is used, it will always occur
396.

Sometimes the overhead of keeping track of a hole might be                          

A. larger than the memory
B. larger than the hole itself
C. very small
D. all of the mentioned
Answer» B. larger than the hole itself
397.

When the memory allocated to a process is slightly larger than the process, then

A. internal fragmentation occurs
B. external fragmentation occurs
C. both internal and external fragmentation occurs
D. neither internal nor external fragmentation occurs
Answer» A. internal fragmentation occurs
398.

Physical memory is broken into fixed-sized blocks called                  

A. frames
B. pages
C. backing store
D. none of the mentioned
Answer» A. frames
399.

Logical memory is broken into blocks of the same size called                    

A. frames
B. pages
C. backing store
D. none of the mentioned
Answer» B. pages
400.

Every address generated by the CPU is divided into two parts. They are

A. frame bit & page number
B. page number & page offset
C. page offset & frame bit
D. frame offset & page offset
Answer» B. page number & page offset
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