EP0303856A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and apparatus for maintaining duplex-paired devices by means of a dual copy function
Assignee: International Business Machines Corp
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Filing: 1988-07-26
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Granted: —
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Expires: 2008-07-26
Abstract
Abstract A technique is described for managing data storage devices and the data stored on them. A pair of data storage devices are maintained as identical copies. The dual copy function is provided without changing any current system or application software on the host. A set of status information is maintained for each record on the data storage device. This status information includes information which allows only the changed records to be copied to the secondary device of the dual copy. This technique also provides high availability of data storage devices by swapping a failing data storage device with a good data storage device without host intervention. A joint array structure is used for routing host requests for information to and from the correct data storage device and keeping status information concerning the data storage devices.
Inventors
- 👤 Blaine H. Berger
- 👤 Bret P. Smith
- 👤 Brent C. Beardsley
- 👤 Lawrence Herbert Boulia
- 👤 Robert Haver Vosacek
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 06:07
CPC Classifications
G; G06; G06F; G06F13/00; G06F13/10; G06F13/12; G06F13/122; G06F11/00; G06F11/07; G06F11/16; G06F11/20; G06F11/2053; G06F11/2056; G06F11/2082; G06F11/2087; G11; G11C; G11C29/00; G11C29/70; G11C29/74; G06F11/006; G06F11/14; G06F11/1446; G06F11/1448; G06F11/1451; G06F11/2064
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
219 words
A data processing system having a host system, an attached controller comprising a set of storage paths attached to a cache, a data storage device controller, and a non-volatile storage, and a memory containing a joint array structure comprising a data translation table and a status table, the data storage device controller comprising attaching means for a plurality of strings of data storage devices, each of the strings comprising a plurality of data storage devices having a plurality of records, a plurality of tracks, and a device status track having a reconfiguration count, a device identification number and controller identification number recorded thereon, the status table in the joint array structure comprising a reconfiguration count, a device identification number and a controller identification number for each of the data storage devices, wherein a first and a second data storage device are managed to maintain identical copies of stored data therein by: assigning a predetermined number of bits for each of the records to identify changes to the record; storing a cell number comprising the predetermined number of bits for each of the records from the first data storage device on a stack; checking the stack to identify a set of records which have changed; and writing the set of records which have changed to the second data storage device.
Claim 2
Dependent Claim
219 words
A data processing system having a host system, an attached controller comprising a set of storage paths attached to a cache, a data storage device controller, and a non-volatile storage, and a memory containing a joint array structure comprising a data translation table and a status table, the data storage device controller comprising attaching means for a plurality of strings of data storage devices, each of the strings comprising a plurality of data storage devices having a plurality of records, a plurality of tracks, and a device status track having a reconfiguration count, a device identification number and controller identification number recorded thereon, the status table in the joint array structure comprising a reconfiguration count, a device identification number and a controller identification number for each of the data storage devices, wherein a first and a second data storage device are managed to maintain identical copies of stored data therein by: assigning a predetermined number of bits for each of the records to identify changes to the record; storing a cell number comprising the predetermined number of bits for each of the records from the first data storage device on a stack; checking the stack to identify a set of records which have changed; and writing the set of records which have changed to the second data storage device.
Claim 3
Dependent Claim
60 words
A system as claimed in claim 1, wherein the response to any data storage device failures comprises replacing a failing data storage device with a functioning one of the data storage devices and updating the data translation table in the joint array structure with information identifying the functioning data storage device as the replacement for the failed data storage device.
Claim 4
Independent Claim
57 words
A system as claimed in any preceding claim, wherein an initial memory load of a data storage device is prevented from successfully completing unless the controller identification number and the device identification number in the status table of the controller match the device and controller identification numbers on the device status track of the data storage device.
Claim 5
Independent Claim
60 words
A system as claimed in any preceding claim, wherein the data storage devices are configured to distribute information flow over each of the strings by: connecting each of the data storage devices to the string with the least attached data storage devices; and connecting the plurality of strings to more than one of the data storage device controller attaching means.
Claim 6
Dependent Claim
55 words
A system as claimed in claim 2, wherein the response to any data storage device failures comprises: incrementing the reconfiguration count in the status table of the joint array structure to indicate that a reconfiguration has taken place; and writing the incremented reconfiguration count onto the device status track of the functioning data storage device.
Claim 7
Dependent Claim
232 words
A data processing system for managing a first and a second data storage device which are identical copies without software changes comprising: a host system containing a plurality of channels; a controller attached to at least one of the channels and comprising a set of storage paths, each of the storage paths having access to a cache, a data storage device controller, a non-volatile storage, and a memory comprising a joint array structure having a data translation table and a status table; a plurality of data storage devices attached to the data storage device controller, each of the data storage devices comprising a plurality of tracks, a device status track having a reconfiguration count, a device identification number and controller identification number recorded thereon, and a plurality of records; the joint array structure of the controller comprising a reconfiguration count, a device identification number, and a controller identification number for each of the data storage devices; means for assigning a predetermined number of bits for each of the records to identify changes to the records; means for storing a cell number comprising the predetermined number of bits for each of the records from the first data storage device on a stack; means for checking the stack to identify a set of records which have changed; and means for writing the set of records which have changed to the second data storage device.
Claim 8
Dependent Claim
232 words
A data processing system for managing a first and a second data storage device which are identical copies without software changes comprising: a host system containing a plurality of channels; a controller attached to at least one of the channels and comprising a set of storage paths, each of the storage paths having access to a cache, a data storage device controller, a non-volatile storage, and a memory comprising a joint array structure having a data translation table and a status table; a plurality of data storage devices attached to the data storage device controller, each of the data storage devices comprising a plurality of tracks, a device status track having a reconfiguration count, a device identification number and controller identification number recorded thereon, and a plurality of records; the joint array structure of the controller comprising a reconfiguration count, a device identification number, and a controller identification number for each of the data storage devices; means for assigning a predetermined number of bits for each of the records to identify changes to the records; means for storing a cell number comprising the predetermined number of bits for each of the records from the first data storage device on a stack; means for checking the stack to identify a set of records which have changed; and means for writing the set of records which have changed to the second data storage device.
Claim 9
Dependent Claim
75 words
A system as claimed in claim 6 further comprising means for assuring the integrity of data storage devices after failures by comparing the device identification number and the controller identification number in the status table in the joint array structure with the device identification number and the controller identification number on the device status track of the data storage device and disabling operation if the device identification number and controller identification number do not match.
References Cited (Backward Citations)
No citation records indexed.
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