Operating System-Unix [3i Infotech Placement]: Sample Questions 63 - 65 of 78

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Question 63

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Describe in Detail

Essay▾

What is an advantage of executing a process in background?

Explanation

Executing a Process in Background
  • The most common reason to put a process in the background is to do something else interactively without waiting for the process to complete.
  • This is done by adding a special background symbol, & at end of the command.
  • Tells the shell to execute the given command in the background.
  • Example:
    • cp ⚹ . ⚹ . . / backup& (cp is for copy) .

Question 64

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Write in Short

Short Answer▾

What is the window of the working set of a process?

Explanation

  • Some models uses a parameter k as the working-set window.
  • The idea is to examine the most recent k page references.
  • The set of pages in the most recent k page references is the working set.
  • If a page is in active use, it will in the working set.
  • If page is no longer used, it will drop from the working set k units after its last reference.

Question 65

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Describe in Detail

Essay▾

Is the process before and after the swap are the same?

Explanation

Swapping of Two Processes
  • Process before swapping is residing in the primary memory in original form.
  • All regions however are not occupied by the process with few empty slots in the regions. While swapping kernel ignores empty slots.
  • After swapping the process resides in the swap device.
  • The regions swapped out will not have empty slots that were present before assigning.
  • When the process is brought again into the main memory kernel referring takes care of the empty slots in the regions.

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