Operating System [3i Infotech Placement]: Sample Questions 32 - 34 of 81

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Question 32

Operating System
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Write in Short

Short Answer▾

What is a Region?

Explanation

  • A region is a continuous area of a process՚s address space.
  • Kernel maintains region table in memory local to the process.
  • Regions are sharable among the process.

Question 33

Operating System
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Write in Short

Short Answer▾

What is a Daemon?

Explanation

A daemon process:

  • Runs in the background and is independent of control from all terminals.
  • Comes up during boot-up and terminates when the system is rebooted.
  • Is not attached to a terminal like a foreground process.
  • Either created by a process by forking a child process and then immediately exiting, thus causing init to adopt the child process, or the init process directly launching the daemon.
  • Thus, in a unix environment, the parent process of a daemon is often, but not always, the init process.
  • The operating system typically performs other operations, dissociating the daemon process from any controlling terminal.

Question 34

Operating System
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Describe in Detail

Essay▾

What are the criteria for choosing a process for swapping into memory from the swap device?

Explanation

Understanding of Swap in and Swap Out

Process is Swapped based on:

  • Resident time of the processes in the swap device
  • Priority of the processes
  • Amount of the time the processes had swapped out.

However, a process can swapped temporarily out of memory to a backing store, and then brought back into memory for continued execution.

  • Major part of swap time is transfer time; total transfer time is directly proportional to the amount of memory swapped.
  • Modified versions of swapping are found on many system, UNIX and Micro Windows.

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