well, In addition to the DAT hardware and the segment and page tables required for address translation, paging activity involves a number of system components to handle the movement of pages and several additional tables to keep track of the most current version of each page.

To understand how paging works, assume that DAT encounters an invalid page table entry during address translation, indicating that a page is required that is not in a central storage frame. To resolve this page fault, the system must bring the page in from auxiliary storage. First, however, it must locate an available central storage frame. If none is available, the request must be saved and an assigned frame freed. To free a frame, the system copies its contents to auxiliary storage and marks its corresponding page table entry as invalid. This operation is called a page-out.

After a frame is located for the required page, the contents of the page are copied from auxiliary storage to central storage and the page table invalid bit is set off. This operation is called a page-in.

Paging can also take place when z/OS® loads an entire program into virtual storage. z/OS obtains virtual storage for the user program and allocates a central storage frame to each page. Each page is then active and subject to the normal paging activity; that is, the most active pages are retained in central storage while the pages not currently active might be paged out to auxiliary storage.
source site: http://publib.boulder.ibm.com/infoc enter/zoslnctr/v1r7/index.jsp?topic =/com.ibm.zconcepts.doc/zconcepts_9 1.html

Answered by Santosh Kuma , an ibibo Master, at 10:51 AM on September 27, 2008

When a program is selected for execution, the system brings it into virtual storage, divides it into

pages of four kilobytes, transfers the pages into central storage for execution. To the programmer,

the entire program appears to occupy contiguous space in storage at all times. Actually, not all

pages of a program are necessarily in central storage, and the pages that are in central storage do

not necessarily occupy contiguous space.

The pieces of a program executing in virtual storage must be moved between real and auxiliary

storage. To allow this, z/OS® manages storage in units, or blocks, of four kilobytes. The following

blocks are defined:

A block of central storage is a frame.

A block of virtual storage is a page.

A block of auxiliary storage is a slot.

PLEASE VISIT THE SOURCE SITE FOR MORE INFORMATION :http://publib.boulder.ibm.com /infocenter/zoslnctr/v1r7/inde x.jsp?topic=/com.ibm.zconcepts .doc/zconcepts_90.html

Answered by Sanya Tahir , an ibibo Master, at 8:18 PM on September 06, 2008

Hi Friend,

paging (sometimes called swapping) is a transfer of pages between main memory and an auxiliary store, such as hard disk drive.

Paging is an important part of virtual memory implementation in most contemporary general-purpose operating systems, allowing them to use disk storage for data that does not fit into physical RAM.

Paging is usually implemented as a task built into the kernel of the operating system.

Answered by kokila vani , an ibibo Advisor, at 4:39 PM on September 05, 2008

hi!
In computer operating systems that have their main memory divided into pages, paging (sometimes called swapping) is a transfer of pages between main memory and an auxiliary store, such as hard disk drive.[1] Paging is an important part of virtual memory implementation in most contemporary general-purpose operating systems, allowing them to use disk storage for data that does not fit into physical RAM. Paging is usually implemented as a task built into the kernel of the operating system.

Answered by LAKSHMI V , an ibibo Master, at 4:44 PM on September 04, 2008

When a program is selected for execution, the system brings it into virtual storage, divides it into pages of four kilobytes, transfers the pages into central storage for execution. To the programmer, the entire program appears to occupy contiguous space in storage at all times. Actually, not all pages of a program are necessarily in central storage, and the pages that are in central storage do not necessarily occupy contiguous space.

The pieces of a program executing in virtual storage must be moved between real and auxiliary storage. To allow this, z/OS® manages storage in units, or blocks, of four kilobytes. The following blocks are defined:

* A block of central storage is a frame.
* A block of virtual storage is a page.
* A block of auxiliary storage is a slot.

A page, a frame, and a slot are all the same size: Four kilobytes. An active virtual storage page resides in a central storage frame. A virtual storage page that becomes inactive resides in an auxiliary storage slot (in a paging data set). Figure 1 shows the relationship of pages, frames, and slots.

Answered by jaivir , an ibibo Master, at 10:05 AM on September 04, 2008

One says that the operating system pages the data. Each time a page is needed that is not currently in memory, a page fault occurs. An invalid page fault occurs when the address of the page being requested is invalid. In this case, the application is usually aborted.

This type of virtual memory is called paged virtual memory. Another form of virtual memory is segmented virtual memory.

for more: http://www.webop edia.com/TERM/P/paging.html

Answered by Romi , an ibibo Master, at 8:24 AM on September 04, 2008

The movement of a fixed-size block of computer data between faster main and slower auxiliary memories to optimize performance without the user being aware that the transfer has taken place

Answered by Dan !!!!!! , an ibibo Specialist, at 6:18 AM on September 04, 2008

As for as I AM Concern,A technique used by virtual memory operating systems to help ensure that the data you need is available as quickly as possible. The operating system copies a certain number of pages from your storage device to main memory. When a program needs a page that is not in main memory, the operating system copies the required page into memory and copies another page back to the disk. One says that the operating system pages the data. Each time a page is needed that is not currently in memory, a page fault occurs. An invalid page fault occurs when the address of the page being requested is invalid. In this case, the application is usually aborted.

This type of virtual memory is called paged virtual memory. Another form of virtual memory is segmented virtual memory.

Answered by Sharad Singh , an ibibo Master, at 7:11 PM on September 03, 2008

Well Dear, As much as In know,The operating system copies a certain number of pages from your storage device to main memory. When a program needs a page that is not in main memory, the operating system copies the required page into memory and copies another page back to the disk.

One says that the operating system pages the data. Each time a page is needed that is not currently in memory, a page fault occurs. An invalid page fault occurs when the address of the page being requested is invalid. In this case, the application is usually aborted.

This type of virtual memory is called paged virtual memory. Another form of virtual memory is segmented virtual memory.


http://www.webop edia.com/TERM/P/paging.html

Answered by Madhurima , an ibibo Master, at 6:04 PM on September 03, 2008

A technique used by virtual memory operating systems to help ensure that the data you need is available as quickly as possible. The operating system copies a certain number of pages from your storage device to main memory. When a program needs a page that is not in main memory, the operating system copies the required page into memory and copies another page back to the disk. One says that the operating system pages the data. Each time a page is needed that is not currently in memory, a page fault occurs. An invalid page fault occurs when the address of the page being requested is invalid. In this case, the application is usually aborted.

This type of virtual memory is called paged virtual memory. Another form of virtual memory is segmented virtual memory.

Answered by Shobhit , an ibibo Master, at 4:38 PM on September 03, 2008