Top 500 Questions for Operating System with Answers

Top 500 Questions for Operating System with Answers

Operating System Questions for Competitive Exams are very important for your interview. These Operating System MCQ For Competitive Exams are most important for your preparation.

Operating system questions for competitive exams are very important for your preparation. These questions are very useful for your preparation. Every competitive exam candidate should have to prepare operating system questions for competitive exams. These are most important for your interview.

The live learns team specially create these 100+ Operating system questions and answers pdf to the students totally free of cost.

operating system assignment questions and answers

1. The hardware mechanism that allows a device to notify the CPU is called _______

a) polling

b) interrupt

c) driver

d) controlling

Answer: b


2. The CPU hardware has a wire called __________ that the CPU senses after executing every instruction.

a) interrupt request line

b) interrupt bus

c) interrupt receive line

d) interrupt sense line

Answer: a


3. In general the two interrupt request lines are ____________

a) maskable & non maskable interrupts

b) blocked & non maskable interrupts

c) maskable & blocked interrupts

d) none of the mentioned

Answer: a


4. The _________ are reserved for events such as unrecoverable memory errors.

a) non-maskable interrupts

b) blocked interrupts

c) maskable interrupts

d) none of the mentioned

Answer: a


5. The ________ can be turned off by the CPU before the execution of critical instruction sequences that must not be interrupted.

a) nonmaskable interrupt

b) blocked interrupt

c) maskable interrupt

d) none of the mentioned

Answer: c


6. The __________ is used by device controllers to request service.

a) nonmaskable interrupt

b) blocked interrupt

c) maskable interrupt

d) none of the mentioned

Answer: c


7. The interrupt vector contains ____________

a) the interrupts

b) the memory addresses of specialized interrupt handlers

c) the identifiers of interrupts

d) the device addresses

Answer: b


8. For large data transfers, _________ is used.

a) dma

b) programmed I/O

c) controller register

d) none of the mentioned

Answer: a


9. A character stream device transfers ____________

a) bytes one by one

b) block of bytes as a unit

c) with unpredictable response times

d) none of the mentioned

Answer: a


10. A block device transfers ____________

a) bytes one by one

b) block of bytes as a unit

c) with unpredictable response times

d) none of the mentioned

Answer: b

Operating System Assignment Questions and Answers
Operating System Assignment Questions and Answers

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Operating System Concepts mcq


11. What is a dedicated device?

a) opposite to a sharable device

b) same as a sharable device

c) can be used concurrently by several processes

d) none of the mentioned

Answer: a


12. A keyboard is an example of a device that is accessed through a __________ interface.

a) block stream

b) set of blocks

c) character stream

d) none of the mentioned

Answer: c


13. In polling ____________

a) busy – wait cycles wait for I/O from device

b) interrupt handler receives interrupts

c) interrupt-request line is triggered by I/O device

d) all of the mentioned

Answer: a


14. A non blocking system call _________________

a) halts the execution of the application for an extended time

b) does not halt the execution of the application

c) does not block the interrupts

d) none of the mentioned

Answer: b


15. An asynchronous call ____________

a) returns immediately, without waiting for the I/O to complete

b) does not return immediately and waits for the I/O to complete

c) consumes a lot of time

d) is too slow

Answer: a


16. If one or more devices use a common set of wires to communicate with the computer system, the connection is called ______

a) CPU

b) Monitor

c) Wirefull

d) Bus

Answer: d


17. A ____ a set of wires and a rigidly defined protocol that specifies a set of messages that can be sent on the wires.

a) port

b) node

c) bus

d) none of the mentioned

Answer: c


18. When device A has a cable that plugs into device B, and device B has a cable that plugs into device C and device C plugs into a port on the computer, this arrangement is called a _________

a) port

b) daisy chain

c) bus

d) cable

Answer: b


19. The _________ present a uniform device-access interface to the I/O subsystem, much as system calls provide a standard interface between the application and the operating system.

a) Devices

b) Buses

c) Device drivers

d) I/O systems

Answer: c


20. Spooling ____________

a) holds a copy of the data

b) is fast memory

c) holds the only copy of the data

d) holds output for a device

Answer: c

also check:

system programming and operating system mcq
system programming and operating system mcq

system programming and operating system mcq


21. The ________ keeps state information about the use of I/O components.

a) CPU

b) OS

c) kernel

d) shell

Answer: c


22. The kernel data structures include ____________

a) process table

b) open file table

c) close file table

d) all of the mentioned

Answer: b


23. Windows NT uses a __________ implementation for I/O.

a) message – passing

b) draft – passing

c) secondary memory

d) cache

Answer: a


24. A ________ is a full duplex connection between a device driver and a user level process.

a) Bus

b) I/O operation

c) Stream

d) Flow

Answer: c


25. I/O is a _________ in system performance.

a) major factor

b) minor factor

c) does not matter

d) none of the mentioned

Answer: a


26. If the number of cycles spent busy – waiting is not excessive, then ____________

a) interrupt driven I/O is more efficient than programmed I/O

b) programmed I/O is more efficient than interrupt driven I/O

c) both programmed and interrupt driven I/O are equally efficient

d) none of the mentioned

Answer: b


27. Buffering is done to ____________

a) cope with device speed mismatch

b) cope with device transfer size mismatch

c) maintain copy semantics

d) all of the mentioned

Answer: d


28. Caching is ________ spooling.

a) same as

b) not the same as

c) all of the mentioned

d) none of the mentioned

Answer: b


29. Caching ____________

a) holds a copy of the data

b) is fast memory

c) holds the only copy of the data

d) holds output for a device

Answer: a


30. In rate monotonic scheduling ____________

a) shorter duration job has higher priority

b) longer duration job has higher priority

c) priority does not depend on the duration of the job

d) none of the mentioned

Answer: a

operating system technical interview questions
operating system technical interview questions

operating system technical interview questions


31. In which scheduling certain amount of CPU time is allocated to each process?

a) earliest deadline first scheduling

b) proportional share scheduling

c) equal share scheduling

d) none of the mentioned

Answer: b


32. The problem of priority inversion can be solved by ____________

a) priority inheritance protocol

b) priority inversion protocol

c) both priority inheritance and inversion protocol

d) none of the mentioned

Answer: a


33. Time duration required for scheduling dispatcher to stop one process and start another is known as ____________

a) process latency

b) dispatch latency

c) execution latency

d) interrupt latency

Answer: b


34. Time required to synchronous switch from the context of one thread to the context of another thread is called?

a) threads fly-back time

b) jitter

c) context switch time

d) none of the mentioned

Answer: c


35. Which one of the following is a real time operating system?

a) RTLinux

b) VxWorks

c) Windows CE

d) All of the mentioned

Answer: d


36. VxWorks is centered around ____________

a) wind microkernel

b) linux kernel

c) unix kernel

d) none of the mentioned

Answer: a


37. In real time operating system ____________

a) all processes have the same priority

b) a task must be serviced by its deadline period

c) process scheduling can be done only once

d) kernel is not required

Answer: b


38. Hard real-time operating system has ______________ jitter than a soft real-time operating system.

a) less

b) more

c) equal

d) none of the mentioned

Answer: a


39. For real-time operating systems, interrupt latency should be ____________

a) minimal

b) maximum

c) zero

d) dependent on the scheduling

Answer: a


40. What is Event latency?

a) the amount of time an event takes to occur from when the system started

b) the amount of time from the event occurrence till the system stops

c) the amount of time from event occurrence till the event crashes

d) the amount of time that elapses from when an event occurs to when it is serviced.

Answer: d

os topics for interview
os topics for interview

500+ operating system placement questions


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

Operating System
Operating System

os topics for interview


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


real time operating system interview questions


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


operating system practice questions


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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