Optimal Page Replacement Algorithm

Lists of Descriptive Questions Answers and Short Study Notes On Operating System – Optimal Page Replacement Algorithm

  • (1) Explain Optimal Page Replacement Algorithm

 

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.