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Which of the following statements is false?

  1. Virtual memory implements the translation of a program's address space into physical memory address space
  2. Virtual memory allows each program to exceed the size of the primary memory
  3. Virtual memory increases the degree of multiprogramming
  4. Virtual memory reduces the context switching overhead
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71 votes

(D) should be the answer.

(A) - MMU does this translation but MMU is part of VM (hardware).

(B), (C) - The main advantage of VM is the increased address space for programs, and independence of address space, which allows more degree of multiprogramming as well as option for process security.

(D) - VM requires switching of page tables (this is done very fast via switching of pointers) for the new process and thus it is theoretically slower than without VM. In anyway VM doesn't directly decrease the context switching overhead.

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VM increases the context switching overhead . VM is based on demand paging so more number of swaps == increase context switch , during page fault .

  1. Virtual memory implements the translation of a program's address space into physical memory address space

This statement is Correct.

 Virtual memory require both hardwire (main memory and TLB) and OS support ( to control those hardwire) , that actual translation from program's address space to physical address space is done by main memory .  so statement A is correct . That makes option A wrong.

Only statement D is false and it is the answer .

Answer:

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