US6366986B1
Expired / Lapsed
US
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Method and apparatus for differential backup in a computer storage system
Assignee: EMC Corp
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Filing: 1998-06-30
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Granted: 2002-04-02
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Expires: 2018-06-30
Abstract
Abstract Method and apparatus for backup in restoring data on a computer system are disclosed. Backups may include a differential backup. In a differential backup, only some (but not all) segments of data in a primary copy are backed up. The segments may correspond to physical segments of storage in a storage system, rather than logical level segments of storage. The method and apparatus may include constructing a complete copy of a backed up element from an earlier fill backup and a subsequent differential backup.
Inventors
- 👤 Edgar J. St. Pierre
- 👤 Alton Gill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:58
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/14; G06F11/1446; G06F11/1448; G06F11/1451; G06F11/1458; G06F11/1469
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
117 words
A method of backing up data in a computer storage system, the data being stored in a plurality of identifiable segments, the method comprising steps of: (a) at a first time, identifying which segments have been changed since a preceding backup; (b) forming a first backup that includes a copy of the identified changed segments and omits at least one of the segments that has not changed; and (f) calculating a bit map for a logical element in the first backup that includes information to determine the location of the identified changed segments in the logical element; and wherein the identifiable segments are formed in units corresponding to physical segments of storage in the computer storage system.
Claim 2
Independent Claim
117 words
A method of backing up data in a computer storage system, the data being stored in a plurality of identifiable segments, the method comprising steps of: (a) at a first time, identifying which segments have been changed since a preceding backup; (b) forming a first backup that includes a copy of the identified changed segments and omits at least one of the segments that has not changed; and (f) calculating a bit map for a logical element in the first backup that includes information to determine the location of the identified changed segments in the logical element; and wherein the identifiable segments are formed in units corresponding to physical segments of storage in the computer storage system.
Claim 3
Dependent Claim
19 words
The method of claim 1 , wherein the step (a) comprises a step of receiving a physical bit mask.
Claim 4
Dependent Claim
33 words
The method of claim 1 , wherein the computer storage system stores data according to a fixed block architecture and the identifiable segments correspond to blocks of data in the fixed block architecture.
Claim 5
Dependent Claim
38 words
The method of claim 1 , wherein: the computer storage system stores data on at least one disk drive; the disk drive includes at least one track; and the identifiable segments correspond to tracks on the disk drive.
Claim 6
Dependent Claim
59 words
The method of claim 1 , further comprising steps of: (c) at a second time, identifying which of the identifiable segments have been changed since the preceding backup; and (d) forming a second backup that includes a copy of the changed identifiable segments, identified in step (c), and omits at least one of the segments that has not changed.
Claim 7
Dependent Claim
59 words
The method of claim 1 , further comprising steps of: (c) at a second time, identifying which of the identifiable segments have been changed since the first time; and (d) forming a second backup that includes a copy of the changed identifiable segments, identified in step (c), and omits at least one of the segments that has not changed.
Claim 8
Dependent Claim
61 words
The method of claim 1 , wherein the identifiable segments constitute a logical element, each identifiable segment having a location in the logical element; each identifiable segment is stored in a physical segment of memory; and the step (a) comprises a step of (e) mapping the locations of the identifiable segments in the logical element to the physical segments of memory.
Claim 9
Dependent Claim
26 words
The method of claim 7 , wherein the step (e) comprises a step of converting one or more physical bit masks into a logical bit mask.
Claim 10
Dependent Claim
45 words
The method of claim 1 , wherein: the identifiable segments constitute the logical element, each identifiable segment having a respective location in the logical element; and the step (b) comprises steps of forming a backup file including the identified changed segments and the bit map.
Claim 11
Dependent Claim
23 words
The method of claim 1 , wherein the step (f) comprises a step of determining a logical bit map for the logical element.
Claim 12
Dependent Claim
23 words
The method of claim 1 , wherein the step (f) comprises a step of determining a differential bit map for the logical element.
Claim 13
Dependent Claim
73 words
A backup storage system, comprising: a differential backup generator to receive information specifying which physical segments of storage in a physical storage device have changed data and to generate a differential backup, the differential backup comprising a bit map for a logical element in the first backup that includes information to determine the location of the identified changed segments in the logical element; and a backup storage device to store the differential backup.
Claim 14
Dependent Claim
73 words
A backup storage system, comprising: a differential backup generator to receive information specifying which physical segments of storage in a physical storage device have changed data and to generate a differential backup, the differential backup comprising a bit map for a logical element in the first backup that includes information to determine the location of the identified changed segments in the logical element; and a backup storage device to store the differential backup.
Claim 15
Dependent Claim
16 words
The storage system of claim 12 , wherein the backup storage device comprises a tape drive.
Claim 16
Dependent Claim
35 words
The storage system of claim 12 , further comprising the physical storage device, the physical storage device including means for tracking which of the physical segments have been changed since a preceding level zero backup.
Claim 17
Dependent Claim
34 words
The storage system of claim 12 , further comprising the physical storage device, the physical storage device including means for tracking which of the physical segments have been changed since a preceding differential backup.
Claim 18
Dependent Claim
33 words
The storage system of claim 12 , wherein the differential backup generator comprises means for mapping physical locations of the physical segments to logical locations of the physical segments within a logical element.
Claim 19
Dependent Claim
20 words
The storage system of claim 12 , wherein the differential backup generator comprises means for generating a differential bit file.
Claim 20
Dependent Claim
26 words
The storage system of claim 17 , wherein the differential backup generator further comprises means for generating a differential bit map for the differential bit file.
Claim 21
Dependent Claim
15 words
The method of claim 12 , wherein the bit map comprises a logical bit map.
Claim 22
Dependent Claim
19 words
The method of claim 12 , wherein the bit map comprises a differential bit map for the first backup.
Claim 23
Independent Claim
106 words
A method of forming a complete backup copy of a plurality of segments of data in a computer storage system, the complete backup copy corresponding to the plurality of segments at a target time, the method comprising steps of: (a) providing an earlier backup copy of the plurality of segments corresponding to an earlier time before the target time; (b) providing a first later copy of at least one of the segments, corresponding to a time after the earlier time; and (c) using a bit map for the first later copy to form a complete backup from the earlier backup copy and the first later copy.
Claim 24
Independent Claim
106 words
A method of forming a complete backup copy of a plurality of segments of data in a computer storage system, the complete backup copy corresponding to the plurality of segments at a target time, the method comprising steps of: (a) providing an earlier backup copy of the plurality of segments corresponding to an earlier time before the target time; (b) providing a first later copy of at least one of the segments, corresponding to a time after the earlier time; and (c) using a bit map for the first later copy to form a complete backup from the earlier backup copy and the first later copy.
Claim 25
Dependent Claim
68 words
The method of claim 21 , further comprising a step of providing a second later copy of at least one of the segments, corresponding to a time after the earlier time and before the time of the first later copy; and wherein the step (c) comprises a step of (d) forming the complete backup from the earlier backup copy, the first later copy and the second later copy.
Claim 26
Dependent Claim
31 words
The method of claim 22 , wherein the step (d) comprises a step of selectively copying segments from the earlier backup copy, the first later copy and the second later copy.
Claim 27
Dependent Claim
79 words
A backup storage system, comprising: means for storing an earlier backup copy of a plurality of physical segments constituting a logical element, the earlier backup copy corresponding to an earlier time, and for storing a first later copy of at least one of the segments, corresponding to a time after the earlier time; and means using a bit map for the first later copy to form a complete backup from the earlier backup copy and the first later copy.
Claim 28
Dependent Claim
79 words
A backup storage system, comprising: means for storing an earlier backup copy of a plurality of physical segments constituting a logical element, the earlier backup copy corresponding to an earlier time, and for storing a first later copy of at least one of the segments, corresponding to a time after the earlier time; and means using a bit map for the first later copy to form a complete backup from the earlier backup copy and the first later copy.
Claim 29
Dependent Claim
71 words
The backup storage system of claim 24 , wherein the means for storing comprises means for storing a second later copy of at least one of the segments, corresponding to a time after the earlier time and before the time of the first later copy; and the means for using comprises means for forming the complete backup from the earlier backup copy, the first later copy and the second later copy.
Claim 30
Dependent Claim
71 words
The backup storage system of claim 24 , wherein the means for storing comprises means for storing a second later copy of at least one of the segments, corresponding to a time after the earlier time and before the time of the first later copy; and the means for using comprises means for forming the complete backup from the earlier backup copy, the first later copy and the second later copy.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2005-04-01 | 2005-10-01 | 2006-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-04-01 | 2009-10-01 | 2010-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-04-01 | 2013-10-01 | 2014-04-02 | $7700.00 | Window Closed / Lapsed |