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65 votes

A computer system supports $32$-bit virtual addresses as well as $32$-bit physical addresses. Since the virtual address space is of the same size as the physical address space, the operating system designers decide to get rid of the virtual memory entirely. Which one of the following is true?

  1. Efficient implementation of multi-user support is no longer possible
  2. The processor cache organization can be made more efficient now
  3. Hardware support for memory management is no longer needed
  4. CPU scheduling can be made more efficient now
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6 Answers

Best answer
99 votes
99 votes

A is the best answer here.

Virtual memory provides

  1. increased address space for processes
  2. memory protection
  3. relocation 

So, when we don't need more address space, even if we get rid of virtual memory, we need hardware support for the other two. Without hardware support for memory protection and relocation, we can design a system (by either doing them in software or by partitioning the memory for different users) but those are highly inefficient mechanisms. i.e., there we have to divide the physical memory equally among all users and this limits the memory usage per user and also restricts the maximum number of users.

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7 votes
7 votes
If there is no Virtual memory ,we cannot increase the degree of multiprogramming. so Option A)
2 votes
2 votes
Page 348 Stallings 6th edition

In simple paging, processor uses page number, offset to calculate absolute address.

Hence, A.
0 votes
0 votes
answer c is correct because the hardware support  for virtual memory mapping to physical memory are registers required for page table implementation basically PBTR  register and  TLB for caching the pages, now because the concept of virtual memory is removed hence no hardware components are required.
Answer:

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