Question

What is Virtual Memory?

Answer 1

1. Virtual memory is an attempt, which makes the execution of the processes possible, which may completely not in the main memory. Some part of the process may be on disk.
2. The MM techniques are simple to implement but the major drawback is that if the physical memory is limited then number of processes it can hold at any time i.e. degree of multiprogramming reduces. For this concept of virtual memory is introduced.
3. The primary benefit of virtual memory is the ability to run programs larger than physical memory.
4. Virtual memory is hard to implement. Implementation options include paging segmentation or mixed approaches. Virtual memory systems typically use paging.
5. A software has logical or virtual pages. Program execution begins with loading certain pages into frames. When a page is not loaded into memory and its location is addressed, a page fault occurs. A page fault causes the OS to load the page from disk into memory.