GATE CS 1999 Q2.11 — Memory Management and Virtual Memory

Let us analyze each option to determine the advantages of virtual memory:

• Option A (Incorrect): Virtual memory requires address translation (mapping virtual addresses to physical addresses using page tables and TLB). This translation overhead makes memory access slower on average compared to direct physical memory access.
• Option B (Correct): Virtual memory provides robust memory protection. Since each process is allocated its own distinct virtual address space, a process cannot access or modify the memory of another process unless explicitly shared.
• Option C (Incorrect): Although virtual memory allows programs to be loaded anywhere, address independence from physical memory can be achieved using simpler hardware mechanisms like basic relocation registers (base and limit registers) without requiring a full virtual memory system.
• Option D (Correct): One of the primary benefits of virtual memory is that it enables the execution of programs whose memory requirements exceed the physical capacity of the RAM. Only the currently active pages of the program need to reside in physical memory, while the rest remain on secondary storage.

Therefore, the correct options are B and D.