3i Infotech Papers: Sample Questions 94 - 95 of 1245

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Question number: 94

» Operating System » Unix

Essay Question▾

Describe in Detail

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


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 number: 95

» Basic CS » Operating System

Essay Question▾

Describe in Detail

What are local and global page replacements?


Global and local allocation.

Global and Local Allocation.

Global and local allocation.

Local replacement:

  • An incoming page is brought in only to the relevant process address space.

  • Considers every process individually.

  • Adjusts memory allocation according to relative importance of each process to improve performance.

  • Local replacement is done for one process and one process only.

  • Does not allow a process to replace page in another processes memory

Global replacement:

  • Policy allows any page frame from any process to replace any other page (even page of another process).

  • The latter is applicable to variable partitions model only.

  • Applied to every process unit.

  • Ignore characteristics of individual process behaviour- aims to achieve the best overall performance.