Page replacement takes the following approach.If no frame is free,we find one that is not currently being used and free it.We can free a frame by writing its contents to swap space,and changing the page table(and all other tables) to indicate that the page is no longer in memory.We can now use the freed frame to hold the page for which the process faulted.Page replacement is basic to demand paging.It completes the separation between logical memory and physical memory.With this mechanism,an enormous virtual memory can be provided for programmers on a smaller physical memory.
Page replacement takes the following approach.If no frame is free,we find one that is not currently being used and free it.We can free a frame by writing its contents to swap space,and changing the page table(and all other tables) to indicate that the page is no longer in memory.We can now use the freed frame to hold the page for which the process faulted.Page replacement is basic to demand paging.It completes the separation between logical memory and physical memory.With this mechanism,an enormous virtual memory can be provided for programmers on a smaller physical memory.