Question-1 Explain Optimal Page Replacement Algorithm
Optimal Page Replacement Algorithm
- The moment a page fault occurs, some set of pages will be in the memory.
- One of these pages will be referenced on the very next instruction.
- Other pages may not be referenced until 10, 100, or perhaps 1000 instructions later.
- Each page can be labeled with the number of instructions that will be executed before that page is first referenced.
- The optimal page algorithm simply says that the page with the highest label should be removed.
- The only problem with this algorithm is that it is unrealizable.
- At the time of the page fault, the operating system has no way of knowing when each of the pages will be referenced next.