1000+ Operating System MCQ Questions and Answers with FREE PDF

Operating System MCQ Questions and Answers are most important for your placement preparation. This test consists of Operating System MCQ questions and answers which will help you to prepare for interviews, technical rounds, and competitive exams. This test includes Operating System quizzes, MCQ questions on OS fundamentals, Process Management, Process Synchronization, Inter-process Communication, Deadlocks, Memory Management and File Systems. Practicing these Operating System MCQ Questions and Answers on a regular basis will improve your problem-solving skill which will be helpful in the recruitment process and technical interviews.

Operating System MCQ Questions and Answers

1. 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


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

a) increases

b) decreases

c) changes

d) maintains

Answer: c


3. When memory is divided into several fixed sized partitions, each partition may contain ________

a) exactly one process

b) at least one process

c) multiple processes at once

d) none of the mentioned

Answer: a


4. 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


5. 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


6. 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


7. 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


8. 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


9. 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


10. The disadvantage of moving all processes to one end of the 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


11. __________ is generally faster than _________ and _________

a) first fit, best fit, worst fit

b) best fit, first fit, worst fit

c) worst fit, best fit, first fit

d) none of the mentioned

Answer: a


12. External fragmentation exists when?

a) enough total memory exists to satisfy a request but it is not contiguous

b) the total memory is insufficient to satisfy a request

c) a request cannot be satisfied even when the total memory is free

d) none of the mentioned

Answer: a


13. 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


14. 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


15. 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


16. The main memory accommodates ____________

a) operating system

b) cpu

c) user processes

d) all of the mentioned

Answer: a


17. 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


18. The __________ is used as an index into the page table.

a) frame bit

b) page number

c) page offset

d) frame offset

Answer: b


19. The _____ table contains the base address of each page in physical memory.

a) process

b) memory

c) page

d) frame

Answer: c


20. The size of a page is typically ____________

a) varied

b) power of 2

c) power of 4

d) none of the mentioned

Answer: b


21. With paging there is no ________ fragmentation.

a) internal

b) external

c) either type of

d) none of the mentioned

Answer: b


22. The operating system maintains a ______ table that keeps track of how many frames have been allocated, how many are there, and how many are available.

a) page

b) mapping

c) frame

d) memory

Answer: c


23. Paging increases the ______ time.

a) waiting

b) execution

c) context – switch

d) all of the mentioned

Answer: c


24. Smaller page tables are implemented as a set of _______

a) queues

b) stacks

c) counters

d) registers

Answer: d


25. The page table registers should be built with _______

a) very low speed logic

b) very high speed logic

c) a large memory space

d) none of the mentioned

Answer: b


26. For larger page tables, they are kept in main memory and a __________ points to the page table.

a) page table base register

b) page table base pointer

c) page table register pointer

d) page table base

Answer: a


27. For every process there is a __________

a) page table

b) copy of page table

c) pointer to page table

d) all of the mentioned

Answer: a


28. Time taken in memory access through PTBR is ____________

a) extended by a factor of 3

b) extended by a factor of 2

c) slowed by a factor of 3

d) slowed by a factor of 2

Answer: d


29. Each entry in a translation lookaside buffer (TLB) consists of ____________

a) key

b) value

c) bit value

d) constant

Answer: a


30. If a page number is not found in the TLB, then it is known as a ____________

a) TLB miss

b) Buffer miss

c) TLB hit

d) All of the mentioned

Answer: a


31. An ______ uniquely identifies processes and is used to provide address space protection for that process.

a) address space locator

b) address space identifier

c) address process identifier

d) none of the mentioned

Answer: b


32. The percentage of times a page number is found in the TLB is known as ____________

a) miss ratio

b) hit ratio

c) miss percent

d) none of the mentioned

Answer: b


33. Memory protection in a paged environment is accomplished by ____________

a) protection algorithm with each page

b) restricted access rights to users

c) restriction on page visibility

d) protection bit with each page

Answer: d


34. When the valid – invalid bit is set to valid, it means that the associated page ____________

a) is in the TLB

b) has data in it

c) is in the process’s logical address space

d) is the system’s physical address space

Answer: c


35. Illegal addresses are trapped using the _____ bit.

a) error

b) protection

c) valid – invalid

d) access

Answer: c


36. When there is a large logical address space, the best way of paging would be ____________

a) not to page

b) a two-level paging algorithm

c) the page table itself

d) all of the mentioned

Answer: b


37. In paged memory systems, if the page size is increased, then the internal fragmentation generally ____________

a) becomes less

b) becomes more

c) remains constant

d) none of the mentioned

Answer: b


38. Physical memory is broken into fixed-sized blocks called ________

a) frames

b) pages

c) backing store

d) none of the mentioned

Answer: a


39. 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


40. 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


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