Question 1

If the memory access time is denoted by 'ma' and 'p' is the probability of a page fault (0 <= p <= 1) . Then the effective access time for a demand paged memory is

Accepted Answer

A)  p x ma + (1-p)  x page fault time
B)  ma + page fault time
C)  (1-p)  x ma + p x page fault time
D)  none of the mentioned

Question 2

When using counters to implement LRU, we replace the page with the___________

Accepted Answer

A)  smallest time value
B)  largest time value
C)  greatest size
D)  none of the mentioned A

Question 3

A process is thrashing if___________

Accepted Answer

A)  it is spending more time paging than executing
B)  it is spending less time paging than executing
C)  page fault occurs
D)  swapping can not take place

Question 4

When a page fault occurs, the state of the interrupted process is___________

Accepted Answer

A)  disrupted
B)  invalid
C)  saved
D)  none of the mentioned

Question 5

When a process begins execution with no pages in memory?

Accepted Answer

A)  process execution becomes impossible
B)  a page fault occurs for every page brought into memory
C)  process causes system crash
D)  none of the mentioned

Question 6

A swapper manipulates___________         whereas the pager is concerned with individual___________of a process.

Accepted Answer

A)  the entire process, parts
B)  all the pages of a process, segments
C)  the entire process, pages
D)  none of the mentioned C

Question 7

A page fault occurs when?

Accepted Answer

A)  a page gives inconsistent data
B)  a page cannot be accessed due to its absence from memory
C)  a page is invisible
D)  all of the mentioned B

Question 8

Locality of reference implies that the page reference being made by a process

Accepted Answer

A)  will always be to the page used in the previous page reference
B)  is likely to be one of the pages used in the last few page references
C)  will always be one of the pages existing in memory
D)  will always lead to page faults

Question 9

A memory page containing a heavily used variable that was initialized very early and is in constant use is removed, then the page replacement algorithm used is___________

Accepted Answer

A)  lru
B)  lfu
C)  fifo
D)  none of the mentioned

Question 10

A FIFO replacement algorithm associates with each page the___________

Accepted Answer

A)  time it was brought into memory
B)  size of the page in memory
C)  page after and before it
D)  all of the mentioned

Question 11

LRU page - replacement algorithm associates with each page the___________

Accepted Answer

A)  time it was brought into memory
B)  the time of that page's last use
C)  page after and before it
D)  all of the mentioned

Question 12

The ability to execute a program that is only partially in memory has benefits like

Accepted Answer

A)  the amount of physical memory cannot put a constraint on the program
B)  programs for an extremely large virtual space can be created
C)  throughput increases
D)  all of the mentioned

Question 13

When the page fault rate is low

Accepted Answer

A)  the turnaround time increases
B)  the effective access time increases
C)  the effective access time decreases
D)  turnaround time & effective access time increases

Question 14

What is the Optimal page - replacement algorithm?

Accepted Answer

A)  replace the page that has not been used for a long time
B)  replace the page that has been used for a long time
C)  replace the page that will not be used for a long time
D)  none of the mentioned

Question 15

Which of the following page replacement algorithms suffers from Belady's Anomaly?

Accepted Answer

A)  optimal replacement
B)  lru
C)  fifo
D)  both optimal replacement and fifo

Question 16

There is a set of page replacement algorithms that can never exhibit Belady's Anomaly, called___________

Accepted Answer

A)  queue algorithms
B)  stack algorithms
C)  string algorithms
D)  none of the mentioned

Question 17

Virtual memory is normally implemented by___________

Accepted Answer

A)  demand paging
B)  buses
C)  virtualization
D)  all of the mentioned

Question 18

Users___________that their processes are running on a paged system.

Accepted Answer

A)  are aware
B)  are unaware
C)  may unaware
D)  none of the mentioned

Question 19

Virtual memory allows___________

Accepted Answer

A)  execution of a process that may not be completely in memory
B)  a program to be smaller than the physical memory
C)  a program to be larger than the secondary storage
D)  execution of a process without being in physical memory

Question 20

The valid - invalid bit, in this case, when valid indicates?

Accepted Answer

A)  the page is not legal
B)  the page is illegal
C)  the page is in memory
D)  the page is not in memory

Exam 18: Understanding Virtual Memory and Page Replacement Algorithms

If the memory access time is denoted by 'ma' and 'p' is the probability of a page fault (0 <= p <= 1) . Then the effective access time for a demand paged memory is

Correct AnswerverifiedShow Answer

When using counters to implement LRU, we replace the page with the___________

Correct AnswerverifiedA

A process is thrashing if___________

Correct AnswerverifiedShow Answer

When a page fault occurs, the state of the interrupted process is___________

Correct AnswerverifiedShow Answer

When a process begins execution with no pages in memory?

Correct AnswerverifiedShow Answer

A swapper manipulates___________ whereas the pager is concerned with individual___________of a process.

Correct AnswerverifiedC

A page fault occurs when?

Correct AnswerverifiedB

Locality of reference implies that the page reference being made by a process

Correct AnswerverifiedShow Answer

A memory page containing a heavily used variable that was initialized very early and is in constant use is removed, then the page replacement algorithm used is___________

Correct AnswerverifiedShow Answer

A FIFO replacement algorithm associates with each page the___________

Correct AnswerverifiedShow Answer

LRU page - replacement algorithm associates with each page the___________

Correct AnswerverifiedShow Answer

The ability to execute a program that is only partially in memory has benefits like

Correct AnswerverifiedShow Answer

When the page fault rate is low

Correct AnswerverifiedShow Answer

What is the Optimal page - replacement algorithm?

Correct AnswerverifiedShow Answer

Which of the following page replacement algorithms suffers from Belady's Anomaly?

Correct AnswerverifiedShow Answer

There is a set of page replacement algorithms that can never exhibit Belady's Anomaly, called___________

Correct AnswerverifiedShow Answer

Virtual memory is normally implemented by___________

Correct AnswerverifiedShow Answer

Users___________that their processes are running on a paged system.

Correct AnswerverifiedShow Answer

Virtual memory allows___________

Correct AnswerverifiedShow Answer

The valid - invalid bit, in this case, when valid indicates?

Correct AnswerverifiedShow Answer

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A

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A swapper manipulates_ whereas the pager is concerned with individual_of a process.

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C

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B

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