Browse Prior Art Database

Pager "Write System Call"

IP.com Disclosure Number: IPCOM000039419D
Original Publication Date: 1987-Jun-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Chang, A: AUTHOR [+4]

Abstract

A method is described to permit the Advanced Interactive Executive (AIX*) operation system for the IBM RT PC in its virtual machine environment to write out modified, mapped pages to the appropriate disk location. On the RT PC, the AIX operating system runs in a virtual machine on top of the Virtual Resource Manager (VRM). This system runs in a virtual storage environment supported by demand paging under the control of the VRM. AIX provides a "sync" command which writes modified file system blocks out to disk. There are two types of blocks that can be written out to disk: files mapped to a disk and files which are not mapped. Mapped files are under the control of the VRM pager. Therefore, AIX only has knowledge about file system blocks which are not mapped.

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Pager "Write System Call"

A method is described to permit the Advanced Interactive Executive (AIX*) operation system for the IBM RT PC in its virtual machine environment to write out modified, mapped pages to the appropriate disk location. On the RT PC, the AIX operating system runs in a virtual machine on top of the Virtual Resource Manager (VRM). This system runs in a virtual storage environment supported by demand paging under the control of the VRM. AIX provides a "sync" command which writes modified file system blocks out to disk. There are two types of blocks that can be written out to disk: files mapped to a disk and files which are not mapped. Mapped files are under the control of the VRM pager. Therefore, AIX only has knowledge about file system blocks which are not mapped. AIX can issue a "write system call" to write these blocks out to disk. AIX has no knowledge of the states of mapped blocks (or pages). Therefore, it doesn't have an efficient way of writing out a mapped block to disk. In accordance with the new method, the VRM Purge Page Range SVC provides a service to write out mapped pages to disk. When the AIX virtual machine is doing a "sync" command, it issues this SVC to the VRM, which will write the modified pages in the range out to disk. When the I/O has completed, rather than releasing the pages (like the normal page replacement mechanism does), the pages are kept in primary memory. Therefore, this is not a page replacement. The pager is per...