US5089958A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fault tolerant computer backup system
Assignee: CA Inc
•
Filing: 1989-01-23
•
Granted: 1992-02-18
•
Expires: 2009-01-23
Abstract
Abstract A method and apparatus for storing and retrieving any prior state of a computer system is provided. Upon installation of the system, a base image corresponding to the initial state of the computer system is established and stored on a storage device. The system monitors changes to the state of the host and subsequently stores at least some of these changes on the storage device. These changes are then mapped by location of the stored changes in an address table to enable subsequent retrieval of any selected changes. When the address table becomes full, at least one differential image of the state of the system is subsequently created by compiling all changes to the base image which occurred between creation of the base image and the selected time. A virtual image may thus be created of data stored on the storage device, as such data existed at a predetermined prior point in time, from which data and files may be retrieved and written to the host disk.
Inventors
- 👤 James A. Horton
- 👤 Stephen M. Getz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:04
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/14; G06F11/1446; G06F11/1458; G06F11/1461; G06F11/1448; G06F11/1451; G06F2201/00; G06F2201/815; G11; G11C; G11C29/00; G11C29/70; G11C29/74
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
191 words
A method for storing and retrieving any state of a computer system which has occurred within a time period between a point in time at which the computer system contains at least one of a program and data in an initial state and some later point in time and during the time period data is transferred and such transfer changes the state of the system, comprising the steps of: a) establishing a base image corresponding to the initial state of the computer system; b) storing the base image on at least one storage device; c) monitoring changes to the state of the system; d) storing the changes to the state of the system on the at least one storage device; e) mapping locations of the stored changes in an address table to enable subsequent retrieval of any selected changes; and f) creating, at a selected time when the address table becomes full, subsequent to the establishment of the base image, at least one differential image of the state of the system, by compiling all changes to the base image which occurred between creation of the base image and the selected time.
Claim 2
Independent Claim
191 words
A method for storing and retrieving any state of a computer system which has occurred within a time period between a point in time at which the computer system contains at least one of a program and data in an initial state and some later point in time and during the time period data is transferred and such transfer changes the state of the system, comprising the steps of: a) establishing a base image corresponding to the initial state of the computer system; b) storing the base image on at least one storage device; c) monitoring changes to the state of the system; d) storing the changes to the state of the system on the at least one storage device; e) mapping locations of the stored changes in an address table to enable subsequent retrieval of any selected changes; and f) creating, at a selected time when the address table becomes full, subsequent to the establishment of the base image, at least one differential image of the state of the system, by compiling all changes to the base image which occurred between creation of the base image and the selected time.
Claim 3
Dependent Claim
53 words
The method as described in claim 1, further comprising the step of compiling a virtual image of data stored on the storage device, as such data existed at a preselected prior point in time, wherein the virtual image comprises the base image altered by selected stored changes, as directed by the address table.
Claim 4
Dependent Claim
20 words
The method system as described in claim 1, wherein all changes to the state of the computer system are stored.
Claim 5
Independent Claim
284 words
A method for storing any state of a storage device contained within a computer system which has occurred within a time period between a point in time at which the computer system contains at least one of a program and data in an initial state and some later point in time and during the time period data is transferred and such transfer changes the state of the system, and retrieving a file from such a prior state, comprising the steps of: a) establishing a base image corresponding to the initial state of the computer system; b) storing the base image on at least one storage device; c) monitoring changes to the state of the system; d) storing the changes to the state of the system on the at least one storage device; e) mapping locations of the stored changes in an address table to enable subsequent retrieval of any selected changes; f) creating, at a selected time when the address table becomes full, subsequent to the establishment of the base image, at least one differential image of the state of the system, by compiling all changes to the base image which occurred between creation of the base image and the selected time; g) compiling a virtual image of data stored on the storage device, as such data existed at a preselected prior point in time, wherein the virtual image comprises the base image altered by selected stored changes, as directed by the address table; h) loading the virtual image into the memory of the computer system; i) selecting relevant portions of the virtual image; and j) copying the relevant portions of the virtual image onto a data storage device associated with the computer system.
Claim 6
Independent Claim
284 words
A method for storing any state of a storage device contained within a computer system which has occurred within a time period between a point in time at which the computer system contains at least one of a program and data in an initial state and some later point in time and during the time period data is transferred and such transfer changes the state of the system, and retrieving a file from such a prior state, comprising the steps of: a) establishing a base image corresponding to the initial state of the computer system; b) storing the base image on at least one storage device; c) monitoring changes to the state of the system; d) storing the changes to the state of the system on the at least one storage device; e) mapping locations of the stored changes in an address table to enable subsequent retrieval of any selected changes; f) creating, at a selected time when the address table becomes full, subsequent to the establishment of the base image, at least one differential image of the state of the system, by compiling all changes to the base image which occurred between creation of the base image and the selected time; g) compiling a virtual image of data stored on the storage device, as such data existed at a preselected prior point in time, wherein the virtual image comprises the base image altered by selected stored changes, as directed by the address table; h) loading the virtual image into the memory of the computer system; i) selecting relevant portions of the virtual image; and j) copying the relevant portions of the virtual image onto a data storage device associated with the computer system.
Claim 7
Independent Claim
304 words
A method for storing any state of a storage device contained within a computer system which has occurred within a time period between a point in time at which the computer system contains at least one of a program and data in an initial state and some later point in time and during the time period data is transferred and such transfer changes the state of the system, and retrieving the prior state in its entirety for restoration onto a storage device, comprising the steps of: a) establishing a base image corresponding to the initial state of the computer system; b) storing the base image on at least one storage device; c) monitoring changes to the state of the system; d) storing the changes to the state of the system on the at least one storage device; e) mapping locations of the stored changes in an address table to enable subsequent retrieval of any selected changes; f) creating, at a selected time when the address table becomes full, subsequent to the establishment of the base image, at least one differential image of the state of the system, by compiling all changes to the base image which occurred between creation of the base image and the selected time; g) compiling a virtual image of data stored on the storage device, as such data existed at a preselected prior point in time, wherein the virtual image comprises the base image altered by selected stored changes, as directed by the address table; h) interrogating the storage device to determine the type of the device; i) preparing the device to accept data according to preset parameters determined by the type of the device; j) loading the virtual image into the memory of the computer system; and k) copying the virtual image, sector by sector, onto the storage device.
Claim 8
Independent Claim
304 words
A method for storing any state of a storage device contained within a computer system which has occurred within a time period between a point in time at which the computer system contains at least one of a program and data in an initial state and some later point in time and during the time period data is transferred and such transfer changes the state of the system, and retrieving the prior state in its entirety for restoration onto a storage device, comprising the steps of: a) establishing a base image corresponding to the initial state of the computer system; b) storing the base image on at least one storage device; c) monitoring changes to the state of the system; d) storing the changes to the state of the system on the at least one storage device; e) mapping locations of the stored changes in an address table to enable subsequent retrieval of any selected changes; f) creating, at a selected time when the address table becomes full, subsequent to the establishment of the base image, at least one differential image of the state of the system, by compiling all changes to the base image which occurred between creation of the base image and the selected time; g) compiling a virtual image of data stored on the storage device, as such data existed at a preselected prior point in time, wherein the virtual image comprises the base image altered by selected stored changes, as directed by the address table; h) interrogating the storage device to determine the type of the device; i) preparing the device to accept data according to preset parameters determined by the type of the device; j) loading the virtual image into the memory of the computer system; and k) copying the virtual image, sector by sector, onto the storage device.
Claim 9
Dependent Claim
291 words
Apparatus for storing and retrieving any state of a computer system having at least one primary data source, which state has occurred within a time period between a point in time at which the computer system contains at least one of a program and data in an initial state and some later point in time and during the time period data is transferred from the prior data source and such transfer changes the state of the system, comprising: 1) processing means; 2) memory means associated with the processing means for transient storage of data, containing software during the operation of the apparatus, the software being capable of directing the apparatus to: a) establish a base image corresponding to the initial state of the computer system; b) store the base image on at least one storage device; c) monitor changes to the state of the system; d) store the changes to the state of the system on the at least one storage device; e) map locations of the stored changes in an address table to enable subsequent retrieval of selected changes; and f) create, at a selected time when the address table becomes full, subsequent to the establishment of the base image, at least one differential image of the state of the system, by compiling all changes to the base image which occurred between creation of the base image and the selected time; 3) means for data communication between the primary data source and the processing means to enable the processing means to detect and record changes to the state of the system in the memory means; and 4) at least one storage device connected to the processing means for maintaining a record of the incremental changes to the primary data source.
Claim 10
Dependent Claim
291 words
Apparatus for storing and retrieving any state of a computer system having at least one primary data source, which state has occurred within a time period between a point in time at which the computer system contains at least one of a program and data in an initial state and some later point in time and during the time period data is transferred from the prior data source and such transfer changes the state of the system, comprising: 1) processing means; 2) memory means associated with the processing means for transient storage of data, containing software during the operation of the apparatus, the software being capable of directing the apparatus to: a) establish a base image corresponding to the initial state of the computer system; b) store the base image on at least one storage device; c) monitor changes to the state of the system; d) store the changes to the state of the system on the at least one storage device; e) map locations of the stored changes in an address table to enable subsequent retrieval of selected changes; and f) create, at a selected time when the address table becomes full, subsequent to the establishment of the base image, at least one differential image of the state of the system, by compiling all changes to the base image which occurred between creation of the base image and the selected time; 3) means for data communication between the primary data source and the processing means to enable the processing means to detect and record changes to the state of the system in the memory means; and 4) at least one storage device connected to the processing means for maintaining a record of the incremental changes to the primary data source.
Claim 11
Dependent Claim
55 words
An apparatus as described in claim 6, wherein the software is also capable of directing the apparatus to compile a virtual image of the storage device, as such data existed at a preselected point in time, whereby the virtual image comprises the base image, altered by selected stored changes, as directed by the address table.
Claim 12
Dependent Claim
15 words
An apparatus as described in claim 6, wherein the computer system is a personal computer.
Claim 13
Dependent Claim
16 words
An apparatus as described in claim 6, wherein the computer system is a network file server.
Claim 14
Dependent Claim
18 words
An apparatus as described in claim 6, wherein the primary data source is a magnetically read hard disk.
Claim 15
Dependent Claim
23 words
An apparatus as described in claim 6, wherein the changes to the state of the system are write actions to a hard disk.
Claim 16
Dependent Claim
17 words
An apparatus as described in claim 6, wherein the storage device is a magnetically read hard disk.
Claim 17
Dependent Claim
16 words
An apparatus as described in claim 6, wherein the storage device is an optically read disk.
Claim 18
Dependent Claim
18 words
An apparatus as described in claim 6, further comprising a secondary storage device connected to the processing means.
Claim 19
Dependent Claim
21 words
An apparatus as described in claim 14, wherein data from the primary data source is mirrored onto the secondary storage device.
Claim 20
Dependent Claim
25 words
An apparatus as described in claim 6, wherein the means for data communication between the processor and the primary data source is an SCSI-type link.
Claim 21
Dependent Claim
25 words
An apparatus as described in claim 6, wherein the means for data communication between the processor and the primary data source is a DMA-type link.
Claim 22
Independent Claim
137 words
A method for storing and retrieving any prior state of a primary data storage device comprising the steps of: a) establishing a base image copy of the primary data storage device; b) storing the base image copy on a secondary storage device; c) monitoring changes to the primary data storage device; d) storing the changes to the primary data storage device on a secondary storage device; e) mapping locations of the stored changes in an address table to enable subsequent retrieval of any selected changes; and f) creating, at a selected time when the address table becomes full, subsequent to the establishment of the base image, at least one differential image of the state of the system, by compiling all changes to the base image which occurred between creation of the base image and the selected time.
Claim 23
Independent Claim
137 words
A method for storing and retrieving any prior state of a primary data storage device comprising the steps of: a) establishing a base image copy of the primary data storage device; b) storing the base image copy on a secondary storage device; c) monitoring changes to the primary data storage device; d) storing the changes to the primary data storage device on a secondary storage device; e) mapping locations of the stored changes in an address table to enable subsequent retrieval of any selected changes; and f) creating, at a selected time when the address table becomes full, subsequent to the establishment of the base image, at least one differential image of the state of the system, by compiling all changes to the base image which occurred between creation of the base image and the selected time.
Claim 24
Dependent Claim
55 words
A method as described in claim 18, further comprising the step of compiling a virtual image of data stored on the secondary storage device, as such data existed at a preselected prior point in time, wherein the virtual image comprises the base image copy altered by selected stored changes, as directed by the address table.
References Cited (Backward Citations)
US3444528A
Cited
US3533082A
Cited
US4164017A
Cited
US4484275A
Cited
US4378588A
Cited
US4156907A
Cited
US4191996A
Cited
US4141066A
Cited
US4351023A
Cited
US4403303A
Cited
US4654857A
Cited
US4486826A
Cited
US4750177A
Cited
US4453215A
Cited
US4459658A
Cited
US4581701A
Cited
US4483001A
Cited
US4479214A
Cited
US4648031A
Cited
US4507751A
Cited
US4498145A
Cited
US4521847A
Cited
US4652940A
Cited
US4654819A
Cited
US4727516A
Cited
US4639856A
Cited
US4607365A
Cited
US4608688A
Cited
US4674038A
Cited
US4754397A
Cited
US4703481A
Cited
US4713811A
Cited
US4736339A
Cited
US4703421A
Cited
US4878167A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-02-17 | 1995-08-19 | 1996-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-02-17 | 1999-08-19 | 2000-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-02-17 | 2003-08-19 | 2004-02-18 | $7700.00 | Window Closed / Lapsed |