| 31. | A LRU page replacement is used with four page frames and eight pages. How many page faults will occur with the reference string 0172327103 if the four frames are initially empty? |
| a. | 6 |
| b. | 7 |
| c. | 8 |
| d. | 5 |
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Answer: (b).7
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| 32. | Match the following for operating system techniques with the most appropriate advantage :
List – I List – II (a) Spooling (i) Allows several jobs in memory to improve CPU utilization (b) Multiprogramming (ii) Access to shared resources among geographically dispersed computers in a transparent way (c) Time sharing (iii) Overlapping I/O and computations (d) Distributed computing (iv) Allows many users to share a computer simultaneously by switching processor frequently Codes: a b c d |
| a. | (iii) (i) (ii) (iv) |
| b. | (iii) (i) (iv) (ii) |
| c. | (iv) (iii) (ii) (i) |
| d. | (ii) (iii) (iv) (i) |
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Answer: (b).(iii) (i) (iv) (ii)
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| 33. | Which of the following statements is not true for Multi-Level Feedback Queue processor scheduling algorithm? |
| a. | Queues have different priorities |
| b. | Each queue may have different scheduling algorithm |
| c. | Processes are permanently assigned to a queue |
| d. | This algorithm can be configured to match a specific system under design |
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Answer: (c).Processes are permanently assigned to a queue
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| 34. | What is the most appropriate function of Memory Management Unit (MMU)? |
| a. | It is an associative memory to store TLB |
| b. | It is a technique of supporting multiprogramming by creating dynamic partitions |
| c. | It is a chip to map virtual address to physical address |
| d. | It is an algorithm to allocate and deallocate main memory to a process |
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Answer: (c).It is a chip to map virtual address to physical address
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| 35. | In ___________ allocation method for disk block allocation in a file system, insertion and deletion of blocks in a file is easy. |
| a. | Index |
| b. | Linked |
| c. | Contiguous |
| d. | Bit Map |
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Answer: (b).Linked
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| 36. | Consider a program that consists of 8 pages (from 0 to 7) and we have 4 page frames in the physical memory
for the pages. The page reference string is : 1 2 3 2 5 6 3 4 6 3 7 3 1 5 3 6 3 4 2 4 3 4 5 1 The number of page faults in LRU and optimal page replacement algorithms are respectively (without including initial page faults to fill available page frames with, pages) : |
| a. | 9 and 6 |
| b. | 10 and 7 |
| c. | 9 and 7 |
| d. | 10 and 6 |
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Answer: (b).10 and 7
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| 37. | Which of the following statements is not true about disk-arm scheduling algorithms? |
| a. | SSTF (shortest seek time first) algorithm increases performance of FCFS |
| b. | The number of requests for disk service are not influenced by file allocation method |
| c. | Caching the directories and index blocks in main memory can also help in reducing disk arm movements |
| d. | SCAN and C-SCAN algorithms are less likely to have a starvation problem |
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Answer: (b).The number of requests for disk service are not influenced by file allocation method
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| 38. | Consider the reference string 0 1 2 3 0 1 4 0 1 2 3 4 If FIFO page replacement algorithm is used, then the number of page faults with three page frames and four page frames are .......... and ........... respectively. |
| a. | 10, 9 |
| b. | 9, 9 |
| c. | 10, 10 |
| d. | 9, 10 |
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Answer: (d).9, 10
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| 39. | Suppose there are four processes in execution with 12 instances of a Resource R in a system. The maximum need of each process and current allocation are given below:
Process Max. Need Current Allocation P1 8 3 P2 9 4 P3 5 2 P4 3 1 With reference to current allocation, is system safe? If so, what is the safe sequence? |
| a. | No |
| b. | Yes, P1 P2 P3 P4 |
| c. | Yes, P4 P3 P1 P2 |
| d. | Yes, P2 P1 P3 P4 |
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Answer: (c).Yes, P4 P3 P1 P2
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| 40. | If the Disk head is located initially at track 32, find the number of disk moves required with FCFS scheduling criteria if the disk queue of I/O blocks requests are: 98, 37, 14, 124, 65, 67 |
| a. | 320 |
| b. | 322 |
| c. | 321 |
| d. | 319 |
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Answer: (c).321
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