PAGING.
Paging is a mechanism which helps the Operating System to create VIRTUAL
(faked) address space by swapping code between disk and RAM. This
process is known as Virtual Memory Support.
Paging is an address translation from the Linear to the Physical Address.
The Linear Address Space is divided into fixed length (4kbyte) PAGES.
Similarly, the Physical Address Space is divided into the same fixed length
FRAMES. Within their respective address spaces pages and frames are
numbered sequentially. Paging mechanism assigns a frame number to a
given page number. The pages that have no frames assigned to them are
stored on the disk. When the CPU needs to run the code on any nonassigned
page it generates a Page Fault Exception, upon which the Operating
system reassigns a currently non-used frame to that page and copies the
code from that page on the disk to the newly assigned RAM frame.