Operating system Multiple Choice Questions



operating system

Quiz

1.What is operating system?
a) that controls computer hardware and software resources
b) acts as an intermediary between the computer user and hardware.
c) allows programs to share memory, enabling programs to interact with devices
d) all of the mentioned
Answer : d

2.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


3. What is process?
a) program in High level language kept on disk
b) contents of main memory
c) a program in execution
d) a job in secondary memory
Answer : c

4. Which is the latest mobile version of android?

a)3.0 (Honeycomb)
b)2.3 (Gingerbread)
c)4.09(Icecream Sandwich)
d)7.0(Noughat)

Answer : d

5. In distributed system each processor has its own
a) local memory
b) clock
c) both (a) and (b)
d) none of the mentioned
Answer : c

6. 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

7. What is Thread?
a) Light Weight Process(LWP)
b) Heavy Weight Process(HWP)
c) Process
d) None of these
Answer : a

8) The kernel is _______ of user threads.
a) a part of
b) the creator of
c) unaware of
d) aware of
Answer : c

9) What is a long-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 these
Answer : a

10) The FIFO algorithm :
a) first executes the job that came in last in the queue
b) first executes the job that came in first in the queue
c) first executes the job that needs minimal processor
d) first executes the job that has maximum processor needs.
Answer : b


11.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

12) 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 these
Answer : c


13) Semaphore is accessed through two special operations called
a) wait
b) stop
c) signal
d) Both a and c
Answer : d

14) 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 these
Answer : c

15) 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

16) The two kinds of semaphores are
a) mutex and counting
b) binary and counting
c) counting and mutex
d) decimal and binary
Answer : b

17)What are the requirements for the solution of critical section problem?
a)Mutual Exclusion
b)Progress
c)Bounded Waiting
d)All of the above
Answer : d



18)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

19)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

20) Every address generated by the CPU is divided into two parts
a) frame bit and offset
b) page number and offset
c) frame number and page number
d) frame offset and status word
Answer : b

21)The __________ is used as an index into the page table.
a) frame bit
b) page number
c) page offset
d) frame offset
Answer : b

22) Physical memory is broken into fixed-sized blocks called
a) frames
b) pages
c) backing store
d) None of these
Answer : a

23) For every process there is a.
a) page table
b) copy of page table
c) pointer to page table
d) All of these
Answer : a

24) The segment base contains the :
a) starting logical address of the process
b) starting physical address of the segment in memory
c) segment length
d) None of these
Answer : b

25) The segment limit contains the :
a) starting logical address of the process
b) starting physical address of the segment in memory
c) segment length
d) None of these
Answer : c



26)Because of virtual memory, the memory can be shared among
a) processes
b) threads
c) instructions
d) none of the mentioned
Answer : a

27) _____ is the concept in which a process is copied into main memory from the secondary memory according to the requirement.
a) Paging
b) Demand paging
c) Segmentation
d) Swapping
Answer : b

28) Virtual memory allows :
a) execution of a process that is completely in memory
b) a program to be larger than the physical memory
c) a program to be larger than the secondary storage
d) execution of a process without being in physical memory
Answer : b

29) The valid – invalid bit, in this case, when valid indicates :
a) the page is legal
b) the page is illegal
c) the page is in memory
d) Both a and c
Answer : d


30) A page fault occurs when :
a) a page gives inconsistent data
b) a page cannot be accesses due to its absence from memory
c) a page is invisible
d) All of these
Answer : b

31)Which of the following one is used by Memory management unit translate the virtual address in to physical address.
a) Memory table
b) Virtual table
c) Page table
d) None of the above
Answer : c

32) The aim of creating page replacement algorithms is to :
a) replace pages faster
b) increase the page fault rate
c) decrease the page fault rate
d) to allocate multiple pages to processes
Answer : c

33) Optimal page – replacement algorithm is :
a) Replace the page that has not been used for a long time
b) Replace the page that has been used for a long time
c) Replace the page that will not be used for a long time
d) None of these
Answer : c

34) LRU page – replacement algorithm associates with each page the ______
a) time it was brought into memory
b) the time of that page’s last use
c) page after and before it
d) All of these
Answer : b


35)______ is a unique tag, usually a number, identifies the file within the file system.
a) File identifier
b) File name
c) File type
d) none of the mentioned
Answer : a

36)File type can be represented by
a) file name
b) file extension
c) file identifier
d) none of the mentioned
Answer : b

37)Which file is a sequence of bytes organized into blocks understandable by the system’s linker?
a) object file
b) source file
c) executable file
d) text file
Answer : a
38)What is the mounting of file system?
a) crating of a filesystem
b) deleting a filesystem
c) attaching portion of the file system into a directory structure
d) removing portion of the file system into a directory structure
Answer : c

39) File attributes consist of :
a) name
b) type
c) identifier
d) All of the above
Answer : d

40) In the sequential access method, information in the file is processed
a) one disk after the other, record access doesn't matter
b) one record after the other
c) one text document after the other
d) None of these
Answer : b

41) The index contains :
a) names of all contents of file
b) pointers to each page
c) pointers to the various blocks
d) All of these
Answer : c

42) In the single level directory
a) All files are contained in different directories all at the same level
b) All files are contained in the same directory
c) Depends on the operating system
d) None of these
Answer : b

43) In the two level directory structure :
a) each user has his/her own user file directory
b) the system has its own master file directory
c) both a and b
d) None of these
Answer : c

44) Path names can be of two types
a) absolute and relative
b) local and relative
c) global and absolute
d) relative and direct
Answer : a

45) An absolute path name begins at the :
a) leaf
b) stem
c) current directory
d) root
Answer : d

46) A mount point is :
a) an empty directory at which the mounted file system will be attached
b) a location where everytime file systems are mounted
c) is the time when the mounting is done
d) None of these
Answer : a

47)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

48) 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 these
Answer : a

49) A block device transfers :
a) bytes one by one
b) block of bytes as a unit
c) with unpredictable response times
d) None of these
Answer : b

50)What is Device controller?
a)interface between device and a driver
b)Interface between hardware and main memory
c)Interface between cache and main memory
d)None of the above
Answer : a

51) In _______, information is recorded magnetically on platters.
a) magnetic disks
b) electrical disks
c) assemblers
d) cylinders
Answer : a

52) The time taken to move the disk arm to the desired cylinder is called the :
a) positioning time
b) random access time
c) seek time
d) rotational latency
Answer : c

53) The disk bandwidth is :
a) the total number of bytes transferred
b) total time between the first request for service and the completion on the last transfer
c) the total number of bytes transferred divided by the total time between the first request for service and the completion on the last transfer
d) None of these

Answer : c

54) Consider a disk queue with requests for I/O to blocks on cylinders :
98 183 37 122 14 124 65 67

i) Considering FCFS (first cum first served) scheduling, the total number of head movements is, if the disk head is initially at 53 :
a) 600
b) 620
c) 630
d) 640
Answer : d

ii) Considering SSTF (shortest seek time first) scheduling, the total number of head movements is, if the disk head is initially at 53 :
a) 224
b) 236
c) 245
d) 240
Answer : b

55) In the ______ algorithm, the disk arm starts at one end of the disk and moves toward the other end, servicing requests till the other end of the disk. At the other end, the direction is reversed and servicing continues.
a) LOOK
b) SCAN
c) C-SCAN
d) C-LOOK
Answer : b

56) In the _______ algorithm, the disk head moves from one end to the other , servicing requests along the way. When the head reaches the other end, it immediately returns to the beginning of the disk without servicing any requests on the return trip.
a) LOOK
b) SCAN
c) C-SCAN
d) C-LOOK
Answer : c

57)In the ______ algorithm, the disk arm goes as far as the final request in each direction, then reverses direction immediately without going to the end of the disk.
a) LOOK
b) SCAN
c) C-SCAN
d) C-LOOK
Answer : a


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