Arnon R Kanfi

US Patent:

56424965, Jun 24, 1997

Filed:

Sep 23, 1993

Appl. No.:

8/125943

Inventors:

Arnon Kanfi - Randolph NJ

International Classification:

G06F 1216

US Classification:

395489

Abstract:

A method is provided for making a backup copy of the content of a memory, e. g. , a database, such that the memory is divided into a plurality of segments and a backup copy of individual ones of the segments is made during a respective one of a plurality of independent backup sessions. Each segment may be a predetermined percentage of the memory, and the independent sessions may be separated from one another by a predetermined duration of time, e. g. , a day. A full backup of the memory is thus completed during a last one of the backup sessions. An incremental backup copy may be made for each of the blocks of segments whose contents has changed since a previous backup session.

US Patent:

55599915, Sep 24, 1996

Filed:

Jun 27, 1995

Appl. No.:

8/495242

Inventors:

Arnon Kanfi - Randolph NJ

Assignee:

Lucent Technologies Inc. - Murray Hill NJ

International Classification:

G06F 1216

US Classification:

395489

Abstract:

A facility is provided for storing in a backup memory only those blocks of a file, or disk partition, which differ from corresponding blocks forming an earlier version of the file. Specifically, a file is divided into a number of blocks and a "signature" is generated for each such block. A block is then stored in the backup memory only if its associated signature differs from a signature generated for an earlier version of the block. In addition, if two blocks of the current version of the file have identical signatures and are to be stored in the backup memory, then only one of the two blocks is stored in the memory and a simple message indicating that the other block is equal to the one block is stored in the memory for the other block. Further, the application of such signatures is advantageously applied to the opposite case of restoring a file using copies of previous versions of the file that are stored in the backup memory.