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4 votes
4 votes

Which of the following are the likely causes of thrashing?

  1. Page size was very small.
  2. There are too many users connected to the system.
  3. Least recently used policy is used for page replacement.
  4. First in First out policy is used for page replacement.

6 Answers

Best answer
9 votes
9 votes

Answer is A

With a computer, thrashing or disk thrashing describes a condition when a page is moved to hard sick from main memory inorder to bring in another page and the moved out page has to come to main memory again which causes another important page to be swapped out and this causes a chain of page swaps and thus slowing down the system enormously. Thrashing occurs when the system does not have enough memory, the system swap file is not properly configured, too much is running at the same time, or has low system resources.

Even if users are more we cannot say it can directly cause thrashing as they need not be using a lot of memory. (Increasing the level of multitasking is a possible cause of thrashing as it causes more no. of processes to require pages in memory simultaneously)

A is a better answer here because if page size is large there will be lesser number page swaps -- say if page size is 4KB, and there are 100 page swaps, if page size is made 8KB, we expect the number of page swaps to be reduced to 50 (this can be any value from 0-100, but expected value is 50).

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2 votes
2 votes
B) There are too many users connected to the system.
1 votes
1 votes

thrashing is due to page fault . if required page not in main memory i.e one can be frame are not able to hold all pages needed

size of frames = size of pages so if page size is small it will result in many frames and pages so chances less of page fault but we can't conclude from that just .

and we know FIFO suffer belady's anomal FIFO as even on incresing frame size or page size for few refrences it will suffer thrashing always

but i feel  it is B as for some references fifo would be good for some page size

but if increse user many process may be in one cpu so many page refernces  might  causing page faults

Answer:

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