Basic CS-Operating System [3i Infotech Placement]: Sample Questions 78 - 79 of 89

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Question 78

Operating System

Describe in Detail


What is mutant?


  • Mutant provides kernel mode or user mode in Windows NT, mutual exclusion with the notion of ownership.
  • Window NT is a Microsoft window personal computer operating system it is designed for users and businesses needing capacity.
  • The server is designed for business machines that need to provide services for network-attached computers.
  • Internal part of biology that mutation in a gene, it is possible to establish the normal function of the gene.

User Mode:

  • Executing code has no ability to directly access hardware or memory.
  • When run code in user mode delegate to system API to access hardware or memory.
  • The protection by this sort of isolation, crashes in user mode is always recoverable.

Kernel mode:

  • The executing code has complete and unrestricted access to the underlying hardware.
  • Execute any CPU instruction and reference any memory address.
  • Generally reserved for the lowest-level.

Question 79

Operating System

Write in Short

Short Answer▾

Which function should be used to free the memory allocated by calloc () ?


  • free () is a function used to free the memory allocated dynamically, by both malloc and calloc functions.
  • free (ptr) ;
  • ptr is a pointer to a memory block which has already been created by malloc or calloc.
  • The memory we give back by calling free () is immediately available to other parts of program.
  • When we program exits, any allocated memory not freed is automatically released by the operating system.
  • Used data is prepended to the allocated block to manage the heap. If memory pointed to was not allocated by a heap allocation function as malloc () or calloc () , then the data preceding the block will be management data.

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