Demand Paging
Definition – demand paging is a procedure that is similar to paging in real memory where pages a process uses are brought into memory; however, a lazy swapper called a pager is used to bring in only those pages needed by the process
Hardware support for distinguishing between pages in memory and pages in memory but swapped into secondary memory uses the valid/invalid bit
Page table – marks pages valid/invalid
Secondary memory – holds those pages not present in memory, usually high speed disk