Virtual memory allows processes to access memory addresses that exceed the amount of physical memory available. When a process references a memory page that is not in RAM, a page fault occurs which brings the missing page into memory from disk. Page replacement algorithms are used to determine which page to remove from RAM to make room for the faulting page. The working set model aims to keep the active pages used by each process in memory to reduce thrashing, which occurs when the total memory demand exceeds the available RAM.

3. Virtual Memory That is Larger Than Physical Memory

5. Transfer of a Paged Memory to Contiguous Disk Space

7. Page Table When Some Pages Are Not in Main Memory

9. Steps in Handling a Page Fault

16. Memory Mapped Files

18. Need For Page Replacement

20. Page Replacement

22. Graph of Page Faults Versus The Number of Frames

24. FIFO Page Replacement

25. FIFO Illustrating Belady’s Anamoly

27. Optimal Page Replacement

29. LRU Page Replacement

31. Use Of A Stack to Record The Most Recent Page References

33. Second-Chance (clock) Page-Replacement Algorithm

41. Locality In A Memory-Reference Pattern

43. Working-set model

51. Reason Why Frames Used For I/O Must Be In Memory

55. Solar Page Scanner