Browse Prior Art Database

Reduction of Directory Management and File Extension Overhead

IP.com Disclosure Number: IPCOM000062210D
Original Publication Date: 1986-Oct-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Duvall, KE: AUTHOR [+4]

Abstract

By detecting an extension request (Write system call or a Store operation), excessive system overhead is eliminated by avoiding the need for an I/O write operation for files which are being extended. Considerable system overhead exists for I/O operations for files which are being created or extended in a UNIX* operating environment. When the extension request is detected, a new page is committed to the disk (though not actually written) by removing the page from the free list and updating the appropriate count fields in the i-node and user areas. The page is then mapped using the "Write New" functions of the Virtual Memory Manager (VMM) which initializes the page to zero automatically, and schedules the page to be written to disk at purge page range supervisor call time (close time). * Trademark of AT&T Bell Laboratories.

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Reduction of Directory Management and File Extension Overhead

By detecting an extension request (Write system call or a Store operation), excessive system overhead is eliminated by avoiding the need for an I/O write operation for files which are being extended. Considerable system overhead exists for I/O operations for files which are being created or extended in a UNIX* operating environment. When the extension request is detected, a new page is committed to the disk (though not actually written) by removing the page from the free list and updating the appropriate count fields in the i-node and user areas. The page is then mapped using the "Write New" functions of the Virtual Memory Manager (VMM) which initializes the page to zero automatically, and schedules the page to be written to disk at purge page range supervisor call time (close time). * Trademark of AT&T Bell Laboratories.

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