Operating System [3i Infotech Placement]: Sample Questions 58 - 60 of 81

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Question 58

Operating System
Edit

Write in Short

Short Answer▾

For which kind of fault the page is checked first?

Explanation

  • The page is first checked for the validity fault. Kernel handles the validity fault.
  • Processes incur protection fault for other reasons which are checked later.

Question 59

Operating System
Edit

Describe in Detail

Essay▾

How the Swapper works?

Explanation

  • Swapper is the process that swaps other processes.
  • Moving the information from fast access memory and slow access memory and vice versa is known swapping.
  • The physical RAM is divided into chunks of memory known as pages.
  • A page memory is copied to the preconfigured space on the hard disk, for the purpose of freeing up that page of memory.
  • The commands swapon and swapoff are used in linux/unix to perform swapping.
  • The swapon is to enable the swapping and the swap off is to disable swapping.
  • On “swapon” The first task for the kernel is to start the swapper process.
  • The swapper process is the part of the kernel that schedules other process.
  • The swapper has process ID of 0.

Question 60

Operating System

Question

MCQ▾

The very first process created by the kernal that runs till the kernal process is halts is

Choices

Choice (4)

a.

init

b.

getty

c.

None of the above

d.

Question does not provide sufficient data or is vague

Answer

c.

Explanation

  • Swapper is the first process created by kernel which in turn activates the init process.
  • Swapper is also known as scheduler.
  • While booting, special process called the ‘swapper’ or ‘scheduler’ is created with Process- ID 0.
  • The swapper manages memory allocation for processes and influences CPU allocation.
  • The swapper inturn creates 3 children:
    • The process dispatcher,
    • vhand and
    • dbflush
  • With IDs and respectively.
  • Dispatcher then spawns shell.
  • Unix keeps track of all the processes in an internal data structure called the Process Table.

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