MCQOPTIONS
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MCQOPTIONS
This section includes 657 Mcqs, each offering curated multiple-choice questions to sharpen your Testing Subject knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
We have a process that has been allocated 3 page frames and initially none of the pages of the process are available in the memory. The following sequence of page references (reference string) is made by the process : 1, 2, 1, 3, 7, 4, 5, 6, 3, 1If Optimal Page Replacement policy is used,_______ page faults will occur for the above reference string. |
| A. | 7 |
| B. | 8 |
| C. | 9 |
| D. | 6 |
| Answer» B. 8 | |
| 2. |
We have a process that has been allocated 3 page frames and initially none of the pages of the process are available in the memory. The following sequence of page references (reference string) is made by the process : 1, 2, 1, 3, 7, 4, 5, 6, 3, 1How many page faults will occur for the above reference string with the Least Recently Used(LRU) Page Replacement Policy in comparison to an Optimal Page Replacement policy? |
| A. | 3 |
| B. | 2 |
| C. | 1 |
| D. | 0 |
| Answer» C. 1 | |
| 3. |
Consider a virtual memory system that uses First In First Out (FIFO) page replacement policy and it allocates a fixed number of frames to a process. Consider the following two statements,1: Sometimes the page fault rate is increased if the number of page frames allocated is increased.2: Some programs do not exhibit Locality of reference.Which of the following is true? |
| A. | 1 is false and 2 is true |
| B. | both 1 and 2 are false |
| C. | both 1 and 2 are true but 2 is not the reason for 1 |
| D. | both 1 and 2 are true and 2 is the reason for 1 |
| Answer» D. both 1 and 2 are true and 2 is the reason for 1 | |
| 4. |
Where can the Belady s anomaly occur? |
| A. | LRU Page Replacement Policy |
| B. | MRU Page Replacement Policy |
| C. | Optimal Page Replacement Policy |
| D. | FIFO Page Replacement Policy |
| Answer» E. | |
| 5. |
Why do we translate a virtual address to physical address where a multilevel page table is preferred in comparison to a single level page table? |
| A. | It is required by the translation look-aside buffer |
| B. | It helps to reduce the memory access time to read or write a memory location |
| C. | It helps to reduce the number of page faults in page replacement algorithm |
| D. | It helps to reduce the size of a page table needed to implement the virtual address space of a process |
| Answer» E. | |
| 6. |
Match the following lists:a. Gang scheduling ------------------------------- i. Guaranteed schedulingb. Rate monotonic scheduling ------------------ ii. Real-time schedulingc. Fair share scheduling ------------------------- iii. Thread scheduling |
| A. | a i, b iii, c - ii |
| B. | a iii, b ii, c - i |
| C. | a i, b ii, c - iii |
| D. | a ii, b iii, c - i |
| Answer» C. a i, b ii, c - iii | |
| 7. |
Which page is selected by the Optimal Page Replacement Algorithm? |
| A. | The page that has been used for maximum. |
| B. | The page that has been used minimum. |
| C. | The page that has not been used for the longest time in the past. |
| D. | The page that will not be used for the longest time in the future. |
| Answer» E. | |
| 8. |
Let P1 and P2 be the two processes and S1 and S2 be the two shared Boolean variables. The initial values of S1 and S2 are randomly assigned. For accessing the critical sections of P1 and P2 the methods used by them are given below:Method used by P1While ( S1 == S2 );Critical sectionS1 = S2;Method used by P2While ( S1! = S2 )Critical sectionS2= not (S1);Which statement / s describes that the properties are achieved? |
| A. | Progress but not mutual exclusion |
| B. | Mutual exclusion but not progress |
| C. | Both mutual exclusion and progress |
| D. | Neither mutual exclusion nor progress |
| Answer» C. Both mutual exclusion and progress | |
| 9. |
Consider the following statements:a. With the use of kernel supported threads context switch is faster.b. The entire process can be blocked by the system for user - level threads.c. Kernel supported threads can be scheduled independently.d. User level threads are transparent to the kernel.Which of the above statements are true? |
| A. | a and d |
| B. | a and b |
| C. | b and c |
| D. | a and c |
| Answer» D. a and c | |
| 10. |
Operating System: Which of the following scheduling algorithm is non-pre-emptive? |
| A. | Multilevel feedback queue. |
| B. | Round Robin |
| C. | FIFO |
| D. | None of the above. |
| Answer» D. None of the above. | |
| 11. |
Operating System: Which of the following scheduling policy is well suited for a time shared operating system? |
| A. | First come first serve. |
| B. | Shortest job first |
| C. | Round robin |
| D. | None of the above. |
| Answer» D. None of the above. | |
| 12. |
Operating System: Which RAID level refers to disk mirroring? |
| A. | 0 |
| B. | 1 |
| C. | 2 |
| D. | 3 |
| Answer» C. 2 | |
| 13. |
Operating System: Which one of the following is not a valid state of a thread? |
| A. | running |
| B. | destroying |
| C. | ready |
| D. | blocked |
| Answer» C. ready | |
| 14. |
Operating System: The address generated by the CPU is referred to as: |
| A. | physical address |
| B. | logical address |
| C. | physical as well as logical address. |
| D. | None of the above. |
| Answer» C. physical as well as logical address. | |
| 15. |
Operating System: The optimal page replacement algorithm will select the page that |
| A. | has been used least number of times. |
| B. | has been used most number of times. |
| C. | has been used for the longest time in the past. |
| D. | will not be used for the longest time in future. |
| Answer» E. | |
| 16. |
Data Structure: A complete Binary Tree contains 15 nodes, then how many edges are there in the tree? |
| A. | 15 |
| B. | 30 |
| C. | 14 |
| D. | 16 |
| Answer» D. 16 | |
| 17. |
We have a uniprocessor machine where a set of n tasks with known run times r1, r2, r3, .rn are to be run. What will be the maximum throughput result of the processor scheduling algorithm? |
| A. | Shortest Job First |
| B. | First Come First Served |
| C. | Round Robin |
| D. | Highest Response Ratio Next |
| Answer» B. First Come First Served | |
| 18. |
A system that uses FIFO page replacement policy has 4 page frames with no pages loaded initially. 100 distinct pages are accessed by the system in some order and then the same 100 pages are accessed in the reverse order. How many page faults will occur? |
| A. | 193 |
| B. | 194 |
| C. | 195 |
| D. | 196 |
| Answer» E. | |
| 19. |
An operating system maintains smaller data structures for a thread than a process, as a thread is usually defined as a light weight process . What is the per thread basis of the operating system? |
| A. | Does not maintain a separate stack |
| B. | Maintains only CPU register state. |
| C. | Does not maintain a virtual memory state |
| D. | Maintains only scheduling and accounting information |
| Answer» E. | |
| 20. |
Match the following:List I - - - - - - - - - - - - - - - - - - - - - - - - - List IIa. Multilevel feedback queue - - - - - - - - - i. Time-slicingb. FCFS - - - - - - - - - - - - - - - - - - - - - - - -ii. Criteria to move processes between queuesc. Shortest process next - - - - - - - - - - - -iii. Batch processingd. Round robin scheduling - - - - - - - - - - -iv. Exponential smoothing |
| A. | a-i, b-iii, c-ii, d-iv |
| B. | a-iv, b-iii, c-ii, d-i |
| C. | a-iii, b-i, c-iv, d-i |
| D. | a-ii, b-iii, c-iv, d-i |
| Answer» E. | |
| 21. |
Interrupts which are initiated by an instruction are |
| A. | Internal |
| B. | External |
| C. | Hardware |
| D. | Software |
| Answer» E. | |
| 22. |
Choose the correct option about abstract data type(ADT). |
| A. | An abstract data type is a model of a certain kind of data structure. |
| B. | In abstract data type we know what a specific data type can do, but how it actually does it is hidden. |
| C. | ADT is user defined type. |
| D. | All of the above. |
| Answer» E. | |
| 23. |
Which of the following is correct regarding process in operating system? |
| A. | a program is a passive entity |
| B. | process is an active entity. |
| C. | A process is the unit of work. |
| D. | All of the above. |
| Answer» E. | |
| 24. |
Operating System provides the different types of services to the user. For accessing these services, the interface is provided by the |
| A. | system calls. |
| B. | Application Programming Interface. |
| C. | Native library. |
| D. | None of the above. |
| Answer» B. Application Programming Interface. | |
| 25. |
Some IPV4 address is given below, choose the correct option. |
| A. | 22.34.7.8.20 |
| B. | 200.56.045.78 |
| C. | 200.56.045.78 |
| D. | None of the above. |
| Answer» E. | |
| 26. |
In which of the following page replacement policies Balady s anomaly occurs? |
| A. | Most recently used. |
| B. | LRU |
| C. | FIFO |
| D. | Optimal page replacement policy. |
| Answer» D. Optimal page replacement policy. | |
| 27. |
Which protocol has flow control, but not error control? |
| A. | Simplest |
| B. | Selective-Repeat ARQ |
| C. | Go-Back-N ARQ |
| D. | Stop-and-Wait |
| Answer» E. | |
| 28. |
When size of the memory is increased the page replacement policy that sometimes leads to more page faults is called _________ . |
| A. | FIFO |
| B. | Optimal |
| C. | LRU |
| D. | None of the above |
| Answer» B. Optimal | |
| 29. |
A program is executing in a pure demand paging system with 100 records per page with 1 free main memory frame. The address sequence that is generated by tracing this program is recorded as follows,0100, 0200, 0430, 0499, 0510, 0530, 0560, 0120, 0220, 0240, 0260, 0320, 0370What are the number of page faults? |
| A. | 8 |
| B. | 11 |
| C. | 7 |
| D. | 12 |
| Answer» D. 12 | |
| 30. |
The capacity of a memory unit = (the number of words) * (the number of bits / words). What will be the number of separate address and data lines neededfor a memory of 4k * 16 ? |
| A. | 12 address and 16 data lines |
| B. | 12 address and 12 data lines |
| C. | 11 address and 6 data lines |
| D. | 12 address and 8 data lines |
| Answer» B. 12 address and 12 data lines | |
| 31. |
Consider a uniprocessor computer system that has 2 processes and both of them alternate 10ms CPU bursts with 90ms I / O bursts. Both the processes were created at nearly the same time and can proceed in parallel. What is the scheduling strategy for this system that will result in the least CPU utilization (over a long period of time)? |
| A. | Round Robin scheduling with a time quantum of 5ms |
| B. | First Come First Served scheduling |
| C. | Shortest remaining time first |
| D. | Static priority scheduling with different priorities for the two processes |
| Answer» B. First Come First Served scheduling | |
| 32. |
The average time of service a page fault is 10ms and the time taken to access the memory is 1 s. A 99.99% hit ratio results in average memory their access time is __________. |
| A. | 1.9999 s |
| B. | 1.9999ms |
| C. | 1ms |
| D. | 9.99 s |
| Answer» B. 1.9999ms | |
| 33. |
OS: If the disk head is located initially at 32, find the number of disk moves required with FCFS if the disk queue of I/O blocks requests are 98, 37, 14, 124, 65, 70. |
| A. | 320 |
| B. | 321 |
| C. | 324 |
| D. | None of the above |
| Answer» D. None of the above | |
| 34. |
OS: Resources are allocated to the process on non-sharable basis is |
| A. | mutual exclusion |
| B. | hold and wait |
| C. | no pre-emption |
| D. | circular wait |
| Answer» B. hold and wait | |
| 35. |
OS: Shell is the exclusive feature of which software? |
| A. | UNIX |
| B. | DOS |
| C. | System software |
| D. | Application software |
| Answer» B. DOS | |
| 36. |
OS: Which scheduler performs the "swapping out" or "swapping in"? |
| A. | Long-term scheduling |
| B. | Medium-term scheduling |
| C. | Short-term scheduling |
| D. | None of the above. |
| Answer» C. Short-term scheduling | |
| 37. |
Operating system supports different page replacement policy. From the given below option which is not a valid page replacement policy? |
| A. | Least Recently Used |
| B. | First in first out |
| C. | Currently used policy |
| D. | Optimal page replacement policy |
| Answer» D. Optimal page replacement policy | |
| 38. |
A process executes the code,fork();fork();fork();How many child processes are created? |
| A. | 5 |
| B. | 8 |
| C. | 7 |
| D. | 9 |
| Answer» D. 9 | |
| 39. |
If hardware does not support _________ then a multi - user and multi - processing operating system cannot be implemented. |
| A. | At least two modes of CPU execution |
| B. | Demand paging |
| C. | DMA for disk transfer |
| D. | Address translation |
| Answer» C. DMA for disk transfer | |
| 40. |
On a single processor four jobs are to be executed. At time t = (0) + (jobs arrive in the order of A, B, C, D). The burst CPU time requirements are 4, 1, 8, 1 time units respectively. Under Round Robin Scheduling with the time slice of 1 time unit the completion time of A is ______. |
| A. | 3 |
| B. | 5 |
| C. | 7 |
| D. | 9 |
| Answer» E. | |
| 41. |
What invokes the system calls? (Operating System) |
| A. | A privileged instruction |
| B. | An indirect jump |
| C. | A software interrupt |
| D. | Polling |
| Answer» D. Polling | |
| 42. |
Match the following list1 with list2:a. DMA I/O -------------------------------------- 1. High speed RAMb. Cache ---------------------------------------- 2. Diskc. Interrupt I/O --------------------------------- 3. Printerd. Condition code register ------------------- 4. ALU |
| A. | a 2, b 1, c 3, d - 4 |
| B. | a 4, b 1, c 3, d - 2 |
| C. | a 2, b 3, c 1, d - 4 |
| D. | a 3, b 4, c 2, d - 1 |
| Answer» B. a 4, b 1, c 3, d - 2 | |
| 43. |
Which of the following statements is true for the dirty page in a page table? |
| A. | Helps to maintain LRU information |
| B. | Allows only read on a page |
| C. | Helps to avoid unnecessary writes on paging device |
| D. | None of the above |
| Answer» D. None of the above | |
| 44. |
Which is the system call that is responsible for sending of SYN packets? |
| A. | Bind |
| B. | Socket |
| C. | Connect |
| D. | Listen |
| Answer» D. Listen | |