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Synchronization of Mapped File Read/Write and Copy-On-Write Segments

IP.com Disclosure Number: IPCOM000062312D
Original Publication Date: 1986-Nov-01
Included in the Prior Art Database: 2005-Mar-09

Publishing Venue

IBM

Related People

Authors:
Duvall, KE Hooten, AD [+details]

Abstract

By using the Purge Page Range Supervisor Call (SVC) interface of the Virtual Memory Interface (VMI) the prospect of inverted synchronization errors for shared files is reduced, and the Copy-on-Write and Read/ Write mapped file functions are improved. The synchronization of mapped file Read/Write or Copy-on-Write segments as achieved in a UNIX* "fsync" system call required special handling to eliminate the potential of inverting the segment synchronization sequence. A functional methodology which precludes the overlay of volatile and critical data is as follows: 1. If a Copy-on-Write segment exists, it is synchronized into the Read/Write segment after the Read/Write segment is synchronized and unmapped. After the Copy-on-Write segment is synchronized, the Read/Write segment is remapped. 2.