Frank J Leisz

US Patent:

6505307, Jan 7, 2003

Filed:

Sep 6, 2000

Appl. No.:

09/655730

Inventors:

Jeffrey A. Stell - Exton PA
Frank J. Leisz - Warrington PA
Steven M. OBrien - Audubon PA
James W. Thompson - West Chester PA

Assignee:

Unisys Corporation - Blue Bell PA

International Classification:

H02H 305

US Classification:

714 6, 714710, 711114, 711162

Abstract:

A method and apparatus for ensuring the coherence of multiple copies of the same data at multiple geographic locations is presented. The system operating system, the system operator or some combination of both may determine the physical disks having the file or comprising the disk families containing data which requires protection. Using the MIRROR CREATE commands in a Unisys MCP operating system environment, a mirrored disk pack set is made for each relevant physical disk identified. The disk pack set is distributed amongst at least two geographic locations. For each member of each disk pack set, the STORESAFE+command associates a site identifier with the member corresponding to the members geographic location. During application processing, disk writes for one member of a mirrored set are performed for each member of the set. The MCP operating system checks the results of each disk write to each of the members of the mirrored disk set.