Operating System [3i Infotech Placement]: Sample Questions 4 - 6 of 81

Glide to success with Doorsteptutor material for competitive exams : get questions, notes, tests, video lectures and more- for all subjects of your exam.

Question 4

Operating System
Edit

Describe in Detail

Essay▾

What are conditions on which deadlock can occur while swapping the processes?

Explanation

If the running process depends on the sleeping process but sleeping process cannot be brought in as there is no memory left in the swap device.

  • All processes in the main memory are asleep.
  • Ready to run processes are swapped out.
  • There is no space in the swap device for the new incoming process that are swapped out of the main memory.
  • There is no space in the main memory for the new incoming process.
  • If processes are granted exclusive access to device when deadlock occure.

Question 5

Operating System
Edit

Write in Short

Short Answer▾

What does the swapping system do if it identifies the illegal page for swapping?

Explanation

  • If the disk block descriptor does not contain any record of the faulted page then the attempted memory reference is invalid and the kernel sends a segmentation violation signal to the offending process.
  • This happens when the swapping system identified any invalid memory reference.

Question 6

Operating System
Edit

Describe in Detail

Essay▾

How does the inode map to data block of a file?

Explanation

  • When a file system created, data structures that contain information about files are created.
  • File is represented by a structure, called inode and is identified by inode number.
  • Every file contains the description of the file: include file type, access rights, owners, timestamps, size, pointers to data blocks- the addresses of data blocks allocated to a file are stored in inode.
  • When user requests an I/O operation on the file - kernel converts the current offset to a block number- indexes in the block addresses table and reads or writes the physical block.
  • The inode structure uses fifteen pointers containing:
    • Twelve pointers that directly point to blocks of the file՚s data.
    • One singly indirect pointer.
    • One doubly indirect pointer.
    • One triply indirect pointer

Developed by: