OSG204 FINALLY Questions and Answers 2024
1.Which strategy is a simplest design for speeding up Paging?
a) Page table is loaded into registers
b) Page table is loaded into main memory
c) Page table is loaded into disk
d) Page table is loaded into TLB ** Answ** d
2. The ____ policy is based on the theory that the best page to remove is the one that
has been in memory the longest
a) NRU
b) LRU
c) FIFO
d) LIFO ** Answ** c
3. The page table for each process maintains:
a) The page frame location for each page of the process
b) The page location for each frame of the process
c) The physical memory location of the process
d) None of the other choices ** Answ** a
4. Assume that process A-D make up the set of runnable processes on memory as
B1 B2 B3 A1 A2 A5 A7 D3 D4 D6 C1 C6 C5.
Suppose D gets a page fault.
Which page is replaced using the local policy? Assume that the replaced page is always
a last page.
a) D6
b) B3
c) C5
d) None of the others ** Answ** d
5. Which of the following information bits in the entry of page table is used to indicate
what kinds of access are permitted?
Present/absent bit
Caching disabled
Protection bit
Modified bit ** Answ** a
6. Which of the following is appropriate to determine program size and create page
table?
Process creation
Process execution
Page fault time
Process termination time ** Answ** a
,7. One of the most important innovations of demand paging was that it made ____
feasible
Memory demand
Virtual demand
Virtual paging
Virtual memory ** Answ** d
8. Which of the following statements is incorrect about Translation Look-aside Buffer
(TLB)?
TLB only maintains a subset of the entries stored in the full memory-based page table
When there is a TLB miss the system needs to access the page table
The use of TLB eliminates the need for keeping a page table in memory
None of the other choices ** Answ** c
9. Page replacement algorithms determine
When the system should update page table entries
How many pages should be added to main memory
Which pages should be brought into memory because a process is likely to reference
them soon
Which page to remove to provide space for an incoming page ** Answ** a
10. When a virtual memory system manages memory in fixed length units, which of the
following terms correctly represents its unit?
Frame
Page
Block
Segment ** Answ** b
11. Which of these statements about the algorithm "Worst fit" is true?
Memory Manager scans along the list of segments until it finds a hole that is big
enough.
Memory Manager starting searching the list of segments from the place where it left off
last time.
Memory Manager searches the entire list of segments from beginning to end and take
smallest hole that is adequate.
None of the other choices ** Answ** a
12. Which of following statements about the memory hierarchy is false?
Small amount of fast expensive memory - cache
Some medium-speed medium price main memory
Gigabytes of slow cheap disk storage
None of the other choices ** Answ** d
13. Which of these statements about the algorithm "Best fit" is true?
,Memory Manager scans along the list of segments until it finds a hole that is big
enough.
Memory Manager starting searching the list of segments from the place where it left off
last time.
Memory Manager searches the entire list of segments from beginning to end and take
smallest hole that is adequate.
None of the other choices ** Answ** c
14. Which is not true about "Backing up pages dynamically"?
a) Pages do not have fixed swap area on the disk
b) Requires a disk map in memory
c) When a page is swapped out, an empty disk page is chosen on the fly and disk map
is updated accordingly
d) Needs less main memory than the method "Paging to a static swap area" ** Answ**
a
15. The task of subdividing memory between the OS and processes is performed
automatically by the OS and is called:
Protection
Relocation
Memory Management
All of the other choices ** Answ** c
16. Working set model is used for:
a) Finding the minimum number of frames necessary for a job so that jobs can be run
without "thrashing"
b) Finding the average number of frames a job will need to run smoothly
c) Determining whether page replacement is needed
d) All of the other choices ** Answ** b
17. The actual location in main memory is called a(n):
Relative address
Logical address
Absolute address
None of the other choices ** Answ** c
18. In terms of storage utilization the best method of Dynamic Storage Allocation is:
Next fit
First fit
Best fit
Worst fit ** Answ** b
19. The page size that is too small will generate ____
Excessive internal fragmentation
Very long Page tables
More difficult to calculate actual position
, Excessive external fragmentation ** Answ** b
20. The second-chance page-replacement algorithm
Moves pages found at the head of a FIFO queue with the referenced bit turned on back
to the tail of the queue to avoid replacing
them
Searches through a circular list of pages and replaces the first page it encounters that
has the referenced bit turned off
Relies on a modified bit to determine which page to replace
None of the other choices ** Answ** a
21. What is not the technique of implementation for Virtual Memory?
a) Segmentation
b) Partition
c) Paging
d) All of the other choices ** Answ** b
22. In terms of speed the best method of Dynamic Storage-Allocation is:
Next fit
First fit
Best fit
Worst fit ** Answ** b
23. Which of the following information bits in the entry of page table is used to indicate
Page Fault?
Present/absent bit
Status bit
Referenced bit
Modified bit ** Answ** a
24. Five batch jobs A through E, arrive at a computer center at almost the same time.
They have estimated running times of 8, 6, 2, 10,
and 4 minutes. . Determine the average waiting time for FCFS scheduling. Ignore
process switching overhead.
a) 17 minutes
b) 18 minutes
c) 18.8 minutes
d) 12,8 minutes ** Answ** d
25. Five batch jobs A through E, arrive at a computer center at almost the same time.
They have estimated running times of 8, 6, 2, 10,
and 4 minutes. Their (externally determined) priorities are 3, 5, 2, 1, and 4, respectively,
with 5 being the highest priority. Determine
the average waiting time for Priority scheduling. Ignore process switching overhead.
a) 10,8 minutes
b) 12,8 minutes
1.Which strategy is a simplest design for speeding up Paging?
a) Page table is loaded into registers
b) Page table is loaded into main memory
c) Page table is loaded into disk
d) Page table is loaded into TLB ** Answ** d
2. The ____ policy is based on the theory that the best page to remove is the one that
has been in memory the longest
a) NRU
b) LRU
c) FIFO
d) LIFO ** Answ** c
3. The page table for each process maintains:
a) The page frame location for each page of the process
b) The page location for each frame of the process
c) The physical memory location of the process
d) None of the other choices ** Answ** a
4. Assume that process A-D make up the set of runnable processes on memory as
B1 B2 B3 A1 A2 A5 A7 D3 D4 D6 C1 C6 C5.
Suppose D gets a page fault.
Which page is replaced using the local policy? Assume that the replaced page is always
a last page.
a) D6
b) B3
c) C5
d) None of the others ** Answ** d
5. Which of the following information bits in the entry of page table is used to indicate
what kinds of access are permitted?
Present/absent bit
Caching disabled
Protection bit
Modified bit ** Answ** a
6. Which of the following is appropriate to determine program size and create page
table?
Process creation
Process execution
Page fault time
Process termination time ** Answ** a
,7. One of the most important innovations of demand paging was that it made ____
feasible
Memory demand
Virtual demand
Virtual paging
Virtual memory ** Answ** d
8. Which of the following statements is incorrect about Translation Look-aside Buffer
(TLB)?
TLB only maintains a subset of the entries stored in the full memory-based page table
When there is a TLB miss the system needs to access the page table
The use of TLB eliminates the need for keeping a page table in memory
None of the other choices ** Answ** c
9. Page replacement algorithms determine
When the system should update page table entries
How many pages should be added to main memory
Which pages should be brought into memory because a process is likely to reference
them soon
Which page to remove to provide space for an incoming page ** Answ** a
10. When a virtual memory system manages memory in fixed length units, which of the
following terms correctly represents its unit?
Frame
Page
Block
Segment ** Answ** b
11. Which of these statements about the algorithm "Worst fit" is true?
Memory Manager scans along the list of segments until it finds a hole that is big
enough.
Memory Manager starting searching the list of segments from the place where it left off
last time.
Memory Manager searches the entire list of segments from beginning to end and take
smallest hole that is adequate.
None of the other choices ** Answ** a
12. Which of following statements about the memory hierarchy is false?
Small amount of fast expensive memory - cache
Some medium-speed medium price main memory
Gigabytes of slow cheap disk storage
None of the other choices ** Answ** d
13. Which of these statements about the algorithm "Best fit" is true?
,Memory Manager scans along the list of segments until it finds a hole that is big
enough.
Memory Manager starting searching the list of segments from the place where it left off
last time.
Memory Manager searches the entire list of segments from beginning to end and take
smallest hole that is adequate.
None of the other choices ** Answ** c
14. Which is not true about "Backing up pages dynamically"?
a) Pages do not have fixed swap area on the disk
b) Requires a disk map in memory
c) When a page is swapped out, an empty disk page is chosen on the fly and disk map
is updated accordingly
d) Needs less main memory than the method "Paging to a static swap area" ** Answ**
a
15. The task of subdividing memory between the OS and processes is performed
automatically by the OS and is called:
Protection
Relocation
Memory Management
All of the other choices ** Answ** c
16. Working set model is used for:
a) Finding the minimum number of frames necessary for a job so that jobs can be run
without "thrashing"
b) Finding the average number of frames a job will need to run smoothly
c) Determining whether page replacement is needed
d) All of the other choices ** Answ** b
17. The actual location in main memory is called a(n):
Relative address
Logical address
Absolute address
None of the other choices ** Answ** c
18. In terms of storage utilization the best method of Dynamic Storage Allocation is:
Next fit
First fit
Best fit
Worst fit ** Answ** b
19. The page size that is too small will generate ____
Excessive internal fragmentation
Very long Page tables
More difficult to calculate actual position
, Excessive external fragmentation ** Answ** b
20. The second-chance page-replacement algorithm
Moves pages found at the head of a FIFO queue with the referenced bit turned on back
to the tail of the queue to avoid replacing
them
Searches through a circular list of pages and replaces the first page it encounters that
has the referenced bit turned off
Relies on a modified bit to determine which page to replace
None of the other choices ** Answ** a
21. What is not the technique of implementation for Virtual Memory?
a) Segmentation
b) Partition
c) Paging
d) All of the other choices ** Answ** b
22. In terms of speed the best method of Dynamic Storage-Allocation is:
Next fit
First fit
Best fit
Worst fit ** Answ** b
23. Which of the following information bits in the entry of page table is used to indicate
Page Fault?
Present/absent bit
Status bit
Referenced bit
Modified bit ** Answ** a
24. Five batch jobs A through E, arrive at a computer center at almost the same time.
They have estimated running times of 8, 6, 2, 10,
and 4 minutes. . Determine the average waiting time for FCFS scheduling. Ignore
process switching overhead.
a) 17 minutes
b) 18 minutes
c) 18.8 minutes
d) 12,8 minutes ** Answ** d
25. Five batch jobs A through E, arrive at a computer center at almost the same time.
They have estimated running times of 8, 6, 2, 10,
and 4 minutes. Their (externally determined) priorities are 3, 5, 2, 1, and 4, respectively,
with 5 being the highest priority. Determine
the average waiting time for Priority scheduling. Ignore process switching overhead.
a) 10,8 minutes
b) 12,8 minutes
