Operating System-Unix [3i Infotech Placement]: Sample Questions 58 - 59 of 78

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Question 58

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.

Question 59

Edit

Write in Short

Short Answer▾

What are the phases of swapping a page from the memory?

Explanation

Define Swapping
  • The eligibility for swapping a page is found by the page stealer which puts the eligible pages in a list of pages.
  • The page is copied by the kernel to a swap device and the valid bit in the page table entry is cleared.
  • The data reference count is also decremented and the data table entry is placed at the end of the free list in case its reference count is 0.

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