Operating System MCQ (Multiple Choice Questions) - SchoolingAxis

Operating System MCQ (Multiple Choice Questions)

 Que- A dedicated device is : 

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- opposite to a sharable device        


Que- 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- character stream        


Que- 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- busy - wait cycles wait for I/O from device        


Que- 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- does not halt the execution of the application        


Que- 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- returns immediately, without waiting for the I/O to complete        


Que- 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- all of the mentioned        


Que- Caching is ________ spooling. 

a. same as 

b. not the same as 

c. all of the mentioned 

d. none of the mentioned 


Answer- not the same as        


Que- 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- holds a copy of the data        


Que- 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- holds the only copy of the data        


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

a. CPU 

b. OS 

c. kernel 

d. shell 


Answer- kernel        


Que- The kernel data structures include : 

a. process table 

b. open file table 

c. close file table 

d. all of the mentioned 


Answer- open file table        


Que- Windows NT uses a __________ implementation for I/O 

a. message - passing 

b. draft - passing 

c. secondary memory 

d. cache 


Answer- message - passing        


Que- 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- Stream        


Que- I/O is a _________ in system performance. 

a. major factor 

b. minor factor 

c. does not matter 

d. none of the mentioned 


Answer- major factor        


Que- 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- programmed I/O is more efficient than interrupt driven I/O        


Que- 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- a task must be serviced by its deadline period        


Que- 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- less        


Que- For real time operating systems, interrupt latency should be 

a. minimal 

b. maximum 

c. zero 

d. dependent on the scheduling  


Answer- minimal        


Que- 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- shorter duration job has higher priority        


Que- 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- proportional share scheduling        


Que- 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- priority inheritance protocol        


Que- 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- dispatch latency        


Que- 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- context switch time        


Que- Which one of the following is a real time operating system? 

a. RTLinux 

b. VxWorks 

c. Windows CE 

d. All of the mentioned  


Answer- All of the mentioned         


Que- VxWorks is centered around 

a. wind microkernel 

b. linux kernel 

c. unix kernel 

d. none of the mentioned  


Answer- wind microkernel        


Que- The disadvantage of real addressing mode is : 

a. there is a lot of cost involved 

b. time consumption overhead 

c. absence of memory protection between processes 

d. restricted access to memory locations by processes 


Answer- absence of memory protection between processes        


Que- Preemptive, priority based scheduling guarantees : 

a. hard real time functionality 

b. soft real time functionality 

c. protection of memory 

d. none of the mentioned 


Answer- soft real time functionality        


Que- Real time systems must have : 

a. preemptive kernels 

b. non preemptive kernels 

c. preemptive kernels or non preemptive kernels 

d. neither preemptive nor non preemptive kernels 


Answer- preemptive kernels        


Que- Event latency is : 

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


Que- Interrupt latency refers to the period of time : 

a. from the occurrence of an event to the arrival of an interrupt 

b. from the occurrence of an event to the servicing of an interrupt 

c. from arrival of an interrupt to the start of the interrupt service routine 

d. none of the mentioned 


Answer- from arrival of an interrupt to the start of the interrupt service routine        


Que- Real time systems need to __________ the interrupt latency. 

a. minimize 

b. maximize 

c. not bother about 

d. none of the mentioned 


Answer- minimize        


Que- The amount of time required for the scheduling dispatcher to stop one process and start another is known as ______________ 

a. event latency 

b. interrupt latency 

c. dispatch latency 

d. context switch 


Answer- dispatch latency        


Que- The most effective technique to keep dispatch latency low is to : 

a. provide non preemptive kernels 

b. provide preemptive kernels 

c. make it user programmed 

d. run less number of processes at a time 


Answer- provide preemptive kernels        


Que- Priority inversion is solved by use of _____________ 

a. priority inheritance protocol 

b. two phase lock protocol 

c. time protocol 

d. all of the mentioned 


Answer- priority inheritance protocol        


Que- In a real time system the computer results : 

a. must be produced within a specific deadline period 

b. may be produced at any time 

c. may be correct 

d. all of the mentioned 


Answer- must be produced within a specific deadline period        


Que- In a safety critical system, incorrect operation : 

a. does not affect much 

b. causes minor problems 

c. causes major and serious problems 

d. none of the mentioned 


Answer- causes major and serious problems        


Que- Antilock brake systems, flight management systems, pacemakers are examples of : 

a. safety critical system 

b. hard real time system 

c. soft real time system 

d. safety critical system  and hard real time system 


Answer- safety critical system  and hard real time system        


Que- In a ______ real time system, it is guaranteed that critical real time tasks will be completed within their deadlines. 

a. soft 

b. hard 

c. critical 

d. none of the mentioned 


Answer- hard        


Que- Some of the properties of real time systems include : 

a. single purpose 

b. inexpensively mass produced 

c. small size 

d. all of the mentioned 


Answer- all of the mentioned        


Que- The amount of memory in a real time system is generally : 

a. less compared to PCs 

b. high compared to PCs 

c. same as in PCs 

d. they do not have any memory 


Answer- less compared to PCs        


Que- The priority of a real time task : 

a. must degrade over time 

b. must not degrade over time 

c. may degrade over time 

d. none of the mentioned 


Answer- must not degrade over time        


Que- Memory management units : 

a. increase the cost of the system 

b. increase the power consumption of the system 

c. increase the time required to complete an operation 

d. all of the mentioned 


Answer- all of the mentioned        


Que- The technique in which the CPU generates physical addresses directly is known as : 

a. relocation register method 

b. real addressing 

c. virtual addressing 

d. none of the mentioned 


Answer- real addressing        


Que- Earliest deadline first algorithm assigns priorities according to : 

a. periods 

b. deadlines 

c. burst times 

d. none of the mentioned 


Answer- deadlines        


Que- A process P1 has a period of 50 and a CPU burst of t1 = 25, P2 has a period of 80 and a CPU burst of 35. The total CPU utilization is : 

a. 0.9 

b. 0.74 

c.  0.94 

d. 0.8 


Answer-  0.94        


Que- In the above question, the priorities of P1 and P2 : 

a. remain the same throughout 

b. keep varying from time to time 

c. may or may not be change 

d. none of the mentioned 


Answer- keep varying from time to time        


Que- In Question number 2, can the two processes be scheduled using the EDF algorithm without missing their respective deadlines ? 

a. Yes 

b. No 

c. Maybe 

d. None of the mentioned 


Answer- Yes        


Que- Using EDF algorithm practically, it is impossible to achieve 100 percent utilization due to : 

a. the cost of context switching 

b. interrupt handling 

c. power consumption 

d. all of the mentioned 


Answer- the cost of context switching        


Que- T shares of time are allocated among all processes out of N shares in __________ scheduling algorithm. 

a. rate monotonic 

b. proportional share 

c. earliest deadline first 

d. none of the mentioned 


Answer- proportional share        


Que- If there are a total of T = 100 shares to be divided among three processes, A, B and C. A is assigned 50 shares, B is assigned 15 shares and C is assigned 20 shares.A will have ______ percent of the total processor time. 

a. 20 

b. 15 

c. 50 

d. none of the mentioned 


Answer- 50        


Que-  If there are a total of T = 100 shares to be divided among three processes, A, B and C. A is assigned 50 shares, B is assigned 15 shares and C is assigned 20 shares.B will have ______ percent of the total processor time. 

a. 20 

b. 15 

c. 50 

d. none of the mentioned 


Answer- 15        


Que-  If there are a total of T = 100 shares to be divided among three processes, A, B and C. A is assigned 50 shares, B is assigned 15 shares and C is assigned 20 shares.C will have ______ percent of the total processor time. 

a. 20 

b. 15 

c. 50 

d. none of the mentioned 


Answer- 20        


Que-  If there are a total of T = 100 shares to be divided among three processes, A, B and C. A is assigned 50 shares, B is assigned 15 shares and C is assigned 20 shares.If a new process D requested 30 shares, the admission controller would : 

a. allocate 30 shares to it 

b. deny entry to D in the system 

c. all of the mentioned 

d. none of the mentioned 


Answer- deny entry to D in the system        


Que- To schedule the processes, they are considered _________ 

a. infinitely long 

b. periodic 

c. heavy weight 

d. light weight 


Answer- periodic        


Que- If the period of a process is 'p', then the rate of the task is : 

a. p2 

b. 2*p 

c. 1/p 

d. p 


Answer- 1/p        


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