In this section of Operating System Process Management.it contain Operating System Virtual Memory – Demand Paging-1 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.
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1. The memory of the computer system is considered to consist of page frames, where a page frame is memory area that has the same size as a ____
- Page Table
- Page
- Segment
- Page frame table
B. Page
2. Page frames are numbered from ______ Where #frames is the number of page frame of memory
- 1 to #frames
- 1 to #frames-1
- 0 to #frames -1
- Any of the above
C. 0 to #frames -1
3. Each logical address used in a process is considered to be a pair (pi,bi), where pi is a page number and bi is the byte number in pi, Each page is of size s And 0 ≤ bi < s . The effective memory address of a logical address (pi,bi) is computed as follows:
- effective memory address of a logical address (pi,bi) = Start address of the Segment containing page pi + bi
- effective memory address of a logical address (pi,bi) = Start address of the Page Frame containing page pi + bi
- effective memory address of a logical address (pi,bi) = Start address of the Page Frame containing page pi - bi
- None of the above.
B. effective memory address of a logical address (pi,bi) = Start address of the Page Frame containing page pi + bi
4. Memory allocation information for a process is stored in a _______
- Page table
- Frame table
- Pages
- Frame list
A. Page table
Each entry in the page table contains memory allocation information for one page of a process. It contains the page frame number where a page resides.
5. The page table for a process facilitates implementation of address translation, demand loading, and page replacement operations. Which of the followings are the fields in a page table entry
- Valid bit
- Page frame#
- Modified
- Prot info
- All of the above.
E. All of the above.
6. Which of the following field in a page table entry indicates whether the page described by the entry currently exists in memory?
- Valid bit
- Page frame#
- Modified
- Prot info
A. Valid bit
7. Which of the following field in a page table entry indicates which page frame of memory is occupied by the page?
- Valid bit
- Page frame#
- Modified
- Prot info
B. Page frame#
8. Which of the following field in a page table entry indicates how the process may use contents of the page - whether read, write, or execute?
- Ref info
- Modified
- Prot info
- Other info
C. Prot info
9. Which of the following field in a page table entry indicates information concerning references made to the page white it is in memory?
- Ref info
- Modified
- Other info
- Prot info
A. Ref info
10. Which of the following field in a page table entry indicates whether the page has been modified while in memory?
- Ref info
- Modified
- Other info
- Prot info
B. Modified
11. Which of the following field in a page table entry indicates other useful information concerning the page e.g., its position in the swap space?
- Ref info
- Modified
- Other info
- Prot info
C. Other info
12. Which of the following field in the page table entry is also known as presence bit?
- Valid bit
- Page frame#
- Modified
- Prot info
A. Valid bit
13. Which of the following field in the page table entry is also known as dirty bit, and this field is single bit?
- Valid bit
- Page frame#
- Modified
- Prot info
C. Modified
14. Which of the following field is used to decide whether a page out operation is needed while replacing the page?
- Valid bit
- Page frame#
- Modified
- Prot info
C. Modified
the modified bit indicates whether the page has been modified .i.e. whether it is dirty.
15. Which of the following is the step performed in address translation by the MMU?
- Look up page table
- Obtain page number and byte number in a page
- Form effective memory address.
- All of the above.
D. All of the above.
16. When a page is not present in the memory ,MMU raises an interrupt called a __________
- Page hit
- Page miss
- Page Fault
- All of the above.
C. Page Fault
while performing address translation for a logical address pair (pi,bi) , the MMU check the valid bit of the page table entry of pi .if the bit indicates the pi is not present in memory, the MMU raises an interrupt called a missing page interrupt or a page fault.
17. Which of the following operations are performed by the Virtual memory manager when page fault occurs?
- Page in
- Page out
- Page replacement operations
- All of the above.
D. All of the above.
18. The virtual memory manager uses a page replacement algorithm to select one of the pages currently in memory for replacement, accesses the page table entry of the selected page to mark it as “not present” in memory and initiates a ________operation for it if the modified bit of its page table entry indicates that it is dirty page.
- Page hit
- Page out
- Page Miss
- Page in
B. Page out
19. The virtual memory manager initiates a _____ operation to load the required page into the page frame that was occupied by the selected page and it updates the page table entry of the page to record frame number of the page frame, marks the page as “present” and makes provision to resume operation of the process.
- Page hit
- Page out
- Page Miss
- Page in
D. Page in
20. Page-in and page-out operations are required to implement demand paging constitutes _______
- Page I/O
- Process I/O
- Program I/O
- Disk I/O.
A. Page I/O
21. Which of the following stands true for Effective memory access time for a process in demand paging?
- Only Time consumed by the MMU in performing address translation
- Only the average time consumed by the virtual memory manager in handling a page fault
- Time consumed by the MMU in performing address translation and the average time consumed by the virtual memory manager in handling a page fault
- None of the above.
C. Time consumed by the MMU in performing address translation and the average time consumed by the virtual memory manager in handling a page fault
The effective memory access time can be improved by reducing the number of page faults. One way to achieving it is to load pages before they are needed by a process.
22. Which of the following stands true for Effective memory access time for a process in demand paging? Where pr1 = probability that a page exists in memory, tmem = memory access time , tpfh = time overhead of page fault handling
- Effective memory access time = pr1 × 2 × tmem + (1 - pr1 ) × (tmem + tpfh + 2 × tmem)
- Effective memory access time = pr1 × 1 × tmem+ (1 - pr1 ) × (tmem + tpfh + 2 × tmem
- Effective memory access time = pr1 × 1 × tmem1
) × (tmem + tpfh + 2 × tmem) - Effective memory access time = pr1 × 2 × tmem - (1 + pr1 ) × (tmem + tpfh + 2 × tmem )
A. Effective memory access time = pr1 × 2 × tmem + (1 - pr1 ) × (tmem + tpfh + 2 × tmem)
The effective memory access time can be improved by reducing the number of page faults. One way to achieving it is to load pages before they are needed by a process
