[pey-jing] 
| a technique of storage management that transfers pages from secondary storage to main storage when they are required, and returns them to secondary storage when they are not. Compare page 1 (def. 6a). |
[peyj] noun, verb, paged, pag⋅ing.| 1. | one side of a leaf of something printed or written, as a book, manuscript, or letter. |
| 2. | the entire leaf of such a printed or written thing: He tore out one of the pages. |
| 3. | a single sheet of paper for writing. |
| 4. | a noteworthy or distinctive event or period: a reign that formed a gloomy page in English history. |
| 5. | Printing. the type set and arranged for a page. |
| 6. | Computers.
|
| 7. | to paginate. |
| 8. | to turn pages (usu. fol. by through): to page through a book looking for a specific passage. |
[peyj] noun, verb, paged, pag⋅ing.| 1. | a boy servant or attendant. |
| 2. | a youth in attendance on a person of rank or, in medieval times, a youth being trained for knighthood. |
| 3. | an attendant or employee, usually in uniform, who carries messages, ushers guests, runs errands, etc. |
| 4. | a person employed by a legislature to carry messages and run errands for the members, as in the U.S. Congress. |
| 5. | to summon formally by calling out the name of repeatedly: He had his father paged in the hotel lobby. |
| 6. | to summon or alert by electronic pager. |
| 7. | to control (an electrical appliance, machine, etc.) remotely by means of an electronic signal. |
| 8. | to attend as a page. |
| page 1 (pāj) n.
v. tr. To number the pages of; paginate. v. intr. To turn pages: page through a magazine. [French, alteration of Old French pagine, from Latin pāgina; see pag- in Indo-European roots.] page'ful' n. |
| page 2 (pāj) n.
[Middle English, from Old French, possibly from Italian paggio, perhaps ultimately from Greek paidion, diminutive of pais, paid-, child; see pau-1 in Indo-European roots.] |
| pag·ing (pā'jĭng) n. The transfer of pages of data between a computer's main memory and an auxiliary memory. |
paging operating system
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)
