In this section of Operating System Memory Management.it contain Operating System Memory Management – Virtual Memory – Page Replacement Algorithms MCQs (Multiple Choice Questions Answers).All the MCQs (Multiple Choice Question Answers) requires in detail reading of Operating System subject as the hardness level of MCQs have been kept to advanced level.
It covers the below lists of topics
- Optimal page replacement Algorithms
- First-in, First-out (FIFO) page replacement algorithms
- Least recently used (LRU) page replacement algorithms
- Not recently used (NRU) page replacement algorithms
PRACTICE IT NOW TO SHARPEN YOUR CONCEPT AND KNOWLEDGE
1. Page replacement policy should replace a page that is _____
- Likely to be referenced in the immediate future
- Not Likely to be referenced in the immediate future
- Currently in use by the process
- None of the above.
2. In which of the following Page replacement Algorithm making pages replacement decisions in such a manner that the total number of page faults during operation of a process is the minimum possible?
- LRU Page replacement Algorithm
- FIFO page replacement Algorithm
- Optimal page replacement algorithm
- NRU Page replacement algorithm
3. In which of the following Page replacement Policy, at every page fault the page replacement policy replaces the page that was loaded into memory earlier than any other page of the process?
- LRU Page replacement Algorithm
- FIFO page replacement Algorithm
- Optimal page replacement algorithm
- NRU Page replacement algorithm
4. To facilitate FIFO Page replacement, the virtual memory manager records the time of loading of a page in the _________ field of its page table entry.
- Prot info
- Valid bit
- Ref info
- None of the above.
5. To facilitate Optimal Page replacement, the virtual memory manager records the time of loading of a page in the _________ field of its page table entry.
- Prot info
- Valid bit
- Ref info
- None of the above.
6. To facilitate LRU Page replacement, the virtual memory manager records the time of loading of a page in the _________ field of its page table entry.
- Prot info
- Valid bit
- Ref info
- None of the above.
7. In which of the following Page replacement Policy uses the law of locality of reference as the basis for its replacement decisions?
- LRU Page replacement Algorithm
- FIFO page replacement Algorithm
- Optimal page replacement algorithm
- NRU Page replacement algorithm
At every page fault the least recently used (LRU) page is replaced by the required page. The page table entry of a page records the time when the page was last referenced. This information is initialized when page is loaded, and it is updated every time the page is referenced. When page fault occurs, this information is used to locate the page pLRU whose last reference is earlier than that of every other page. This page is replaced with the page whose reference led to the page fault.
8. To achieve the desirable page fault characteristic , a page replacement policy must possess the _________
- Heap property
- Array Property
- Stack Property
- All of the above.
9. Which of the following page replacement algorithm exhibit the stack property ?
- LRU Page replacement Algorithm
- FIFO page replacement Algorithm
- Optimal page replacement algorithm
- NRU Page replacement algorithm
10. Belady’s Anomaly occurs in which of the following page replacement algorithm?
- LRU Page replacement Algorithm
- FIFO page replacement Algorithm
- Optimal page replacement algorithm
- NRU Page replacement algorithm
11. Which of the following statement stands true for Belady’s anomaly?
- The number of page fault decreases when memory allocation for the process is increased
- The number of page fault increases when memory allocation for the process is decreased
- The number of page fault increases when memory allocation for the process is increased
- None of the above.
12. In which of the following algorithm it is possible to combat thrashing by increasing the value of alloc for each process?
- LRU Page replacement Algorithm
- FIFO page replacement Algorithm
- Optimal page replacement algorithm
- NRU Page replacement algorithm
The virtual memory manager cannot use FIFO page replacement policy because increasing the allocation to a process may increase the page fault frequency of the process. This feature would make it difficult to combat thrashing in the system. However, when LRU page replacement is used, the number of page fault is nonincreasing function of alloc. Hence it is possible to combat thrashing by increasing the value of alloc for each process.
13. In which of the following Algorithm where the reference bit is used to determine whether a page has been recently referenced, and some page that has not been recently referenced is replaced?
- LRU Page replacement Algorithm
- FIFO page replacement Algorithm
- Optimal page replacement algorithm
- NRU Page replacement algorithm
The reference bit of a page is initialized to 0 when the page is loaded, and it is set to 1 when page is referenced. it replaces a page whose reference bit is 0.When virtual memory manager finds that the reference bits of all pages have become 1, it reset the bits of all pages to 0 and arbitrarily selects one of the pages for replacement.
