US6141773A
Expired / Lapsed
US
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Method and apparatus for undoing changes to computer memory
Assignee: EMC Corp
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Filing: 1998-06-30
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Granted: 2000-10-31
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Expires: 2018-06-30
Abstract
Abstract Method and apparatus for backing up and restoring data in a computer storage system are disclosed. Changes to segments of memory in a primary copy are tracked. The segments may correspond to how the data is physically stored. Restoration may proceed by returning only those segments that are changed in the primary copy to their state at previous point in time. The backup used for the previous point in time may be a full system backup or a differential backup. A differential backup is one that backs up some segments of memory, but not all of the segments of memory in an element being backed up.
Inventors
- 👤 Edgar J. St. Pierre
- 👤 Alton Gill
- 👤 Madhav Mutalik
- 👤 John Wallace
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:00
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/14; G06F11/1446; G06F11/1458; G06F11/1469; G06F11/1448; G06F11/1451
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
91 words
A method of restoring a primary copy of a plurality of segments of data stored on a physical storage device, the plurality of segments forming a logical element, to a state of the primary copy at a target time, the segments of data being stored in a storage device, the method comprising steps of: (a) identifying which of the segments of data have changed since the target time; and (b) restoring the identified changed segments to the primary copy, while retaining at least one of the segments of the primary copy.
Claim 2
Independent Claim
91 words
A method of restoring a primary copy of a plurality of segments of data stored on a physical storage device, the plurality of segments forming a logical element, to a state of the primary copy at a target time, the segments of data being stored in a storage device, the method comprising steps of: (a) identifying which of the segments of data have changed since the target time; and (b) restoring the identified changed segments to the primary copy, while retaining at least one of the segments of the primary copy.
Claim 3
Dependent Claim
22 words
The method of claim 1, wherein the segments are formed in units corresponding to physical segments of storage in the storage device.
Claim 4
Dependent Claim
31 words
The method of claim 2, wherein the step (b) comprises a step of restoring at least one of the identified changed segments from a level zero backup of the primary copy.
Claim 5
Dependent Claim
16 words
The method of claim 3, wherein the level zero backup is a synthetic level zero backup.
Claim 6
Dependent Claim
64 words
The method of claim 3, wherein the step (b) comprises steps of: restoring at least one of the identified changed segments from a level zero backup of the primary copy at a time at least as early as the target time; and restoring at least one of the identified changed segments from a differential backup of at least one segment of the primary copy.
Claim 7
Dependent Claim
60 words
The method of claim 3, wherein the step (b) comprises steps of: restoring at least one of the identified changed segments from a level zero backup of the primary copy; and restoring at least one of the identified changed segments from each of a plurality of differential backups, each differential backup including at least one segment of the primary copy.
Claim 8
Dependent Claim
18 words
The method of claim 3, wherein the step (a) comprises a step of receiving a physical bit mask.
Claim 9
Dependent Claim
23 words
The method of claim 7, wherein the step (a) comprises a step of converting the physical bit mask to a logical bit mask.
Claim 10
Dependent Claim
112 words
A backup storage system, comprising a restore controller to restore a primary copy of a plurality of segments of data stored on a physical storage device, the plurality of segments forming a logical element, to a state of the primary copy at a target time; and a backup memory system to store and retrieve copies of the segments corresponding to a time at least as early as the target time; and wherein the restore controller comprises a mapper to receive information identifying which of the physical segments in the primary copy have been changed since the target time and to identify corresponding copies of the changed segments in the backup memory system.
Claim 11
Dependent Claim
112 words
A backup storage system, comprising a restore controller to restore a primary copy of a plurality of segments of data stored on a physical storage device, the plurality of segments forming a logical element, to a state of the primary copy at a target time; and a backup memory system to store and retrieve copies of the segments corresponding to a time at least as early as the target time; and wherein the restore controller comprises a mapper to receive information identifying which of the physical segments in the primary copy have been changed since the target time and to identify corresponding copies of the changed segments in the backup memory system.
Claim 12
Dependent Claim
29 words
The backup storage system of claim 9, wherein the backup memory system comprises a memory unit to store a differential backup copy of a portion of the logical element.
Claim 13
Dependent Claim
15 words
The backup storage system of claim 10, wherein the memory unit comprises a tape drive.
Claim 14
Dependent Claim
24 words
The backup storage system of claim 9, wherein the mapper includes a converter to convert a physical bit mask into a logical bit mask.
Claim 15
Dependent Claim
31 words
The backup storage system of claim 9, wherein the mapper includes a backup segment selector to select backup copies of the segments from a plurality of backup copies of the segments.
Claim 16
Dependent Claim
19 words
The backup storage system of claim 13, wherein the plurality of backup copies comprises a level zero backup copy.
Claim 17
Dependent Claim
18 words
The backup storage system of claim 13, wherein the plurality of backup copies comprises a differential backup copy.
Claim 18
Dependent Claim
20 words
The backup storage system of claim 13, wherein the plurality of backup copies comprises a plurality of differential backup copies.
Claim 19
Dependent Claim
19 words
The backup storage system of claim 16, wherein the backup segment selector comprises a catalog for the backup copies.
Claim 20
Dependent Claim
81 words
A backup storage system to restore a primary copy of a plurality of segments of data stored on a physical storage device, the plurality of segments forming a logical element, to a state of the primary copy at a target time, comprising: means for identifying which of the segments of data have changed since the target time; and means for restoring the identified changed segments to the primary copy, while retaining at least one of the segments of the primary copy.
Claim 21
Dependent Claim
81 words
A backup storage system to restore a primary copy of a plurality of segments of data stored on a physical storage device, the plurality of segments forming a logical element, to a state of the primary copy at a target time, comprising: means for identifying which of the segments of data have changed since the target time; and means for restoring the identified changed segments to the primary copy, while retaining at least one of the segments of the primary copy.
Claim 22
Dependent Claim
22 words
The system of claim 18, wherein the segments are formed in units corresponding to physical segments of storage in the storage device.
Claim 23
Dependent Claim
67 words
The system of claim 19, wherein the means for restoring comprises: means for restoring at least one of the identified changed segments from a level zero backup of the primary copy at a time at least as early as the target time; and means for restoring at least one of the identified changed segments from a differential backup of at least one segment of the primary copy.
Claim 24
Dependent Claim
63 words
The system of claim 19, wherein the means for restoring comprises: means for restoring at least one of the identified changed segments from a level zero backup of the primary copy; and means for restoring at least one of the identified changed segments from each of a plurality of differential backups, each differential backup including at least one segment of the primary copy.
Claim 25
Dependent Claim
23 words
The system of claim 19, wherein the means for identifying comprises means for converting a physical bit mask to a logical bit mask.
References Cited (Backward Citations)
US4703481A
Cited
US5119483A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-10-31 | 2004-05-01 | 2004-10-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-10-31 | 2008-05-01 | 2008-10-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-10-31 | 2012-05-01 | 2012-10-31 | $7700.00 | Window Closed / Lapsed |