paging
    n 1: calling out the name of a person (especially by a
         loudspeaker system); "the public address system in the
         hospital was used for paging"
    2: the system of numbering pages [syn: pagination, folio,
       page number, paging]

Page \Page\, v. t. [imp. & p. p. Paged (p[=a]jd); p. pr. & vb.
   n. Paging (p[=a]"j[i^]ng).]
   To mark or number the pages of, as a book or manuscript; to
   furnish with folios.
   [1913 Webster]

Paging \Pa"ging\, n.
   The marking or numbering of the pages of a book.
   [1913 Webster]

paging
paged

    A technique for increasing the memory space
   available by moving infrequently-used parts of a program's
   working memory from RAM to a secondary storage medium,
   usually {hard disk.  The unit of transfer is called a page.

   A memory management unit (MMU) monitors accesses to memory
   and splits each address into a page number (the most
   significant bits) and an offset within that page (the lower
   bits).  It then looks up the page number in its page table.
   The page may be marked as paged in or paged out.  If it is
   paged in then the memory access can proceed after translating
   the virtual address to a physical address.  If the
   requested page is paged out then space must be made for it by
   paging out some other page, i.e. copying it to disk.  The
   requested page is then located on the area of the disk
   allocated for "swap space" and is read back into RAM.  The
   page table is updated to indicate that the page is paged in
   and its physical address recorded.

   The MMU also records whether a page has been modified since it
   was last paged in.  If it has not been modified then there is
   no need to copy it back to disk and the space can be reused
   immediately.

   Paging allows the total memory requirements of all running
   tasks (possibly just one) to exceed the amount of physical
   memory, whereas swapping simply allows multiple processes
   to run concurrently, so long as each process on its own fits
   within physical memory.

   (1996-11-22)