<P> In computer operating systems, paging is a memory management scheme by which a computer stores and retrieves data from secondary storage for use in main memory . In this scheme, the operating system retrieves data from secondary storage in same - size blocks called pages . Paging is an important part of virtual memory implementations in modern operating systems, using secondary storage to let programs exceed the size of available physical memory . </P> <P> For simplicity, main memory is called "RAM" (an acronym of "random - access memory") and secondary storage is called "disk" (a shorthand for "hard disk drive"), but the concepts do not depend on whether these terms apply literally to a specific computer system . </P>

When does the operating system get involved with paging