The paging unit thinks of all RAM as partitioned into fixed-length page frames (they are
sometimes referred to as physical pages). Each page frame contains a page, that is, the length
of a page frame coincides with that of a page. A page frame is a constituent of main memory,
and hence it is a storage area. It is important to distinguish a page from a page frame. the
former is just a block of data, which may be stored in any page frame or on disk.
The data structures that map linear to physical addresses are called page tables. they are
stored in main memory and must be properly initialized by the kernel before enabling the
paging unit.
