David J Wolfe

US Patent:

7085909, Aug 1, 2006

Filed:

Apr 29, 2003

Appl. No.:

10/427403

Inventors:

Rajagopal Ananthanarayanan - Milpitas CA, US
Ralph A. Becker-Szendy - Los Gatos CA, US
Robert M. Rees - Los Gatos CA, US
Randal C. Burns - Washington DC, US
Darrell D. E. Long - Soquel CA, US
David M. Wolfe - Portland OR, US
Jason C. Young - Portland OR, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 12/00

US Classification:

711202, 711162, 711206

Abstract:

Various copy-on-write implementations for a computing environment are presented. One copy-on-write implementation includes employing a read mapping table to perform a first virtual block to physical block mapping for use in reading a block of data of a file to be copy-on-written from physical storage for modification; and employing a different, write mapping table to perform a second virtual block to physical block mapping for use in writing a modified block of the file data to physical storage, wherein copy-on-write of the block of data is achieved using a single write operation. In another implementation, a distributed copy-on-write of a file for a client server environment is presented. This distributed copy-on-write includes performing, by a first client, copy-on-write of at least one block of data of the file to be copy-on-written, and performing, by a second client, copy-on-write of at least one other block of data of the file, wherein multiple clients perform the copy-on-write of the file.