Synchronization of Mapped File Read/Write and Copy-On-Write Segments
Original Publication Date: 1986-Nov-01
Included in the Prior Art Database: 2005-Mar-09
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.