EP0405926A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and apparatus for managing a shadow set of storage media
Assignee: Digital Equipment Corp
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Filing: 1990-06-26
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Granted: —
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Expires: 2010-06-26
Abstract
Abstract A system and method for transferring data from a first storage medium to a second storage medium, each of the storage media being divided into corresponding data blocks, the method comprising steps of: (a) reading data stored in a first data block in the first storage medium, the first data block initially constituting a current data block; (b) comparing data read in the current data block to data stored in a corresponding data block in the second storage medium; (c) if the data compared in step b are identical, reading data stored in a different data block in the first storage medium, the different data block becoming the current data block, and returning to step b; (d) modifying the data stored in one of the storage media such that the data in the current data block is identical to the corresponding data in the second storage medium; and (e) rereading the data in the current data block and returning to step b.
Inventors
- 👤 Scott H. Davis
- 👤 William L. Goleman
- 👤 David W. Thiel
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 13:11
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/16; G06F11/20; G06F11/2053; G06F11/2056; G06F11/2082; G06F11/2087
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
184 words
A method of transferring data from a first storage medium to a second storage medium, said first storage medium being accessible to one or more host processors, each of said storage media being divided into corresponding data blocks, said method comprising the steps of: (a) reading data stored in a first data block in said first storage medium, the first data block initially constituting a current data block; (b) comparing the data read in said current data block to data stored in a corresponding data block in said second storage medium; (c) if the data compared in step b are identical, reading data stored in a different data block in said first storage medium, said different data block becoming the current data block, and returning to step b; (d) if the data compared in step b are not identical, modifying the data stored in one of said storage media such that the data in said current data block is identical to the corresponding data in said second storage medium; and (e) rereading the data in said current data block and returning to step b.
Claim 2
Independent Claim
184 words
A method of transferring data from a first storage medium to a second storage medium, said first storage medium being accessible to one or more host processors, each of said storage media being divided into corresponding data blocks, said method comprising the steps of: (a) reading data stored in a first data block in said first storage medium, the first data block initially constituting a current data block; (b) comparing the data read in said current data block to data stored in a corresponding data block in said second storage medium; (c) if the data compared in step b are identical, reading data stored in a different data block in said first storage medium, said different data block becoming the current data block, and returning to step b; (d) if the data compared in step b are not identical, modifying the data stored in one of said storage media such that the data in said current data block is identical to the corresponding data in said second storage medium; and (e) rereading the data in said current data block and returning to step b.
Claim 3
Dependent Claim
19 words
The method of claim 1 wherein said step of modifying comprises modifying the data in said second storage medium.
Claim 4
Dependent Claim
35 words
The method of claim 2 wherein said step of modifying comprises writing said data read from the current data block in said first storage medium to the corresponding data block in said second storage medium.
Claim 5
Dependent Claim
20 words
The method of claim 1 wherein said different data block is a data block adjacent to said current data block.
Claim 6
Dependent Claim
26 words
The method of claim 1 wherein each data block in said first storage medium is compared to a corresponding data block in said second storage medium.
Claim 7
Dependent Claim
20 words
The method of claim 1 wherein each of said storage media are members of a shadow set of storage media.
Claim 8
Dependent Claim
19 words
The method of claim 6 wherein each of said storage media may be directly accessed by a host processor.
Claim 9
Dependent Claim
23 words
The method of claim 6 wherein each of said storage media may be directly accessed by each of a plurality of host processors.
Claim 10
Dependent Claim
13 words
The method of claim 1 wherein said storage media are disk storage devices.
Claim 11
Independent Claim
128 words
A method of managing a shadow set of storage media accessible by one or more host processors for I/O operations, comprising the steps of: A. carrying out successive comparisons of data stored in corresponding locations in a plurality of said storage media, respectively; and B. performing a management operation on at least one of said storage media, said management operation comprising, for each of said corresponding locations where said comparisons indicated that the data in said corresponding locations was not identical: a. reading data from locations in one of said storage media and writing said data to corresponding locations in another of said storage media; and b. comparing the data in said corresponding locations after said writing to determine if the data in said corresponding locations is identical.
Claim 12
Independent Claim
128 words
A method of managing a shadow set of storage media accessible by one or more host processors for I/O operations, comprising the steps of: A. carrying out successive comparisons of data stored in corresponding locations in a plurality of said storage media, respectively; and B. performing a management operation on at least one of said storage media, said management operation comprising, for each of said corresponding locations where said comparisons indicated that the data in said corresponding locations was not identical: a. reading data from locations in one of said storage media and writing said data to corresponding locations in another of said storage media; and b. comparing the data in said corresponding locations after said writing to determine if the data in said corresponding locations is identical.
Claim 13
Dependent Claim
127 words
An apparratus for managing a shadow set of storage media accessible by one or more host processors for I/O operations, comprising: means for carrying out successive comparisons of data stored in corresponding locations in a plurality of said storage media, respectively; and means for performing a management operation on at least one of said storage media, said management operation comprising, for each of said corresponding locations where said comparisons indicated that the data in said corresponding locations was not identical: a. reading data from locations in one of said storage media and writing said data to corresponding locations in another of said storage media; and b. comparing the data in said corresponding locations after said writing to determine if the data in said corresponding locations is identical.
Claim 14
Dependent Claim
127 words
An apparratus for managing a shadow set of storage media accessible by one or more host processors for I/O operations, comprising: means for carrying out successive comparisons of data stored in corresponding locations in a plurality of said storage media, respectively; and means for performing a management operation on at least one of said storage media, said management operation comprising, for each of said corresponding locations where said comparisons indicated that the data in said corresponding locations was not identical: a. reading data from locations in one of said storage media and writing said data to corresponding locations in another of said storage media; and b. comparing the data in said corresponding locations after said writing to determine if the data in said corresponding locations is identical.
Claim 15
Dependent Claim
166 words
A program for controlling one or more processors in a digital computer. the digital computer processing at least one process which enables said processors to manage a shadow set of storage media accessible by one or more host processors for I/O operations, said program comprising: a comparison module for enabling one of said processors to carry out successive comparisons of data stored in corresponding locations in a plurality of said storage media, respectively; and a management module for enabling one of said processors to perform a management operation on at least one of said storage media, said management operation comprising, for each of said corresponding locations where said comparisons indicated that the data in said corresponding locations was not identical: a. reading data from locations in one of said storage media and writing said data to corresponding locations in said other storage media; and b. comparing the data in said corresponding locations after said writing to determine if the data in said corresponding locations is identical.
Claim 16
Dependent Claim
166 words
A program for controlling one or more processors in a digital computer. the digital computer processing at least one process which enables said processors to manage a shadow set of storage media accessible by one or more host processors for I/O operations, said program comprising: a comparison module for enabling one of said processors to carry out successive comparisons of data stored in corresponding locations in a plurality of said storage media, respectively; and a management module for enabling one of said processors to perform a management operation on at least one of said storage media, said management operation comprising, for each of said corresponding locations where said comparisons indicated that the data in said corresponding locations was not identical: a. reading data from locations in one of said storage media and writing said data to corresponding locations in said other storage media; and b. comparing the data in said corresponding locations after said writing to determine if the data in said corresponding locations is identical.
Claim 17
Dependent Claim
47 words
The method of claim 1 wherein each of said hosts will transmit any write requests to said storage media first to said first storage medium and, after said write request to said first storage medium has completed, will transmit said write request to said second storage medium.
Claim 18
Dependent Claim
21 words
The method of claim 1 wherein each of said host processors maintains a table including information relating to said data transfer.
Claim 19
Dependent Claim
23 words
The method of claim 10 wherein each of said storage media may be directly accessed by each of a plurality of host processors.
Claim 20
Dependent Claim
53 words
The method of claim 10 wherein each of said hosts will transmit any write requests to said storage media first to said one of said storage media and, after said write request to said one of said storage media has completed, will transmit said write request to said another of said storage media.
Claim 21
Dependent Claim
21 words
The method of claim 10 wherein each of said host processors maintains a table including information relating to said management operation.
Claim 22
Dependent Claim
40 words
The method of claim 10 wherein step B(b) comprises rereading said data from said locations in said one of said storage media and comparing said reread data to data in said corresponding locations in said another of said storage media.
Claim 23
Dependent Claim
31 words
The method of claim 10 wherein steps B(a) and B(b) are repeated recursively for the same corresponding locations until the data stored in said corresponding locations is determined to be identical.
Claim 24
Dependent Claim
53 words
The apparatus of claim 11 wherein each of said hosts will transmit any write requests to said storage media first to said one of said storage media and, after said write request to said one of said storage media has completed, will transmit said write request to said another of said storage media.
Claim 25
Dependent Claim
21 words
The apparatus of claim 11 wherein each of said host processors maintains a table including information relating to said management operation.
Claim 26
Dependent Claim
23 words
The apparatus of claim 11 wherein each of said storage media may be directly accessed by each of a plurality of host processors.
Claim 27
Dependent Claim
44 words
The apparatus of claim 11 wherein said management operation comprises rereading said data from said locations in said one of said storage media after said writing and comparing said reread data to data in said corresponding locations in said another of said storage media.
Claim 28
Dependent Claim
37 words
The apparatus of claim 11 wherein said means for performing said management operation repeats said reading and comparing recursively for the same corresponding locations until the data stored in said corresponding locations is determined to be identical.
References Cited (Backward Citations)
No citation records indexed.
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