Patent EP0097234A2 successfully refreshed from Google Patents.
EP0097234A2
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Method and apparatus for restarting a computing system
Assignee: International Business Machines Corp
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Filing: 1983-05-02
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Granted: —
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Expires: 2003-05-02
Abstract
Abstract A programming metnoa and structure for operating a computing system to restart a total subsystem or a subset of that subsystem to an operable state following a total interruption (system failure or termination, either normal or abnormal). The subsystem isolates inoperable resources while permitting the others to resume by independently maintaining in a first structure 90 the completion state 116, 120 of a resource manager's recovery responsibility with respect to each interrupted work unit and in a second structure 70 the operational states 82 and recovery log interest scopes 84, 86 of each resource manager. The completion state can be influenced by the starting or not of a resource manager, and if restarted, the presence or absence of a resource subset required to accomplish the work unit recovery.
Inventors
- 👤 Earle Henderson Jenner
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 22:12
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/14; G06F11/1402; G06F11/1415; G06F11/1441; G06F16/00; G06F9/00; G06F9/06; G06F9/46; G06F9/461; G06F9/463
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
205 words
A method for operating a computing apparatus including a plurality of resource managers (21) and resource collections (44), and further including a recovery log (40), the computing apparatus (20) being operated according to the method of executing work unit (36) instructions, and writing log records (135) to said recovery log, said log records including checkpointed states (92-96) and records (135) of changes resulting from execution of work unit instructions to said resource collections and resource managers, with each log record assigned a relative byte address within a continuous address space, the method characterized by the steps of: maintaining in a first structure (90) with respect to each of a subset of resource managers (21) the completion state (120) of its recovery responsibility with respect to each interrupted work unit (36), the completion state defining whether or not the resource manager has been restarted and, if restarted, the availability of the subset of resource collections required to complete the work unit; and maintaining in a second structure (70) with respect to each of said subset of said resource managers (21) (1) its operational state (82) and (2) the relative byte addresses in said recovery log of the beginning (84) and ending (80) of its interest scope.
Claim 2
Independent Claim
205 words
A method for operating a computing apparatus including a plurality of resource managers (21) and resource collections (44), and further including a recovery log (40), the computing apparatus (20) being operated according to the method of executing work unit (36) instructions, and writing log records (135) to said recovery log, said log records including checkpointed states (92-96) and records (135) of changes resulting from execution of work unit instructions to said resource collections and resource managers, with each log record assigned a relative byte address within a continuous address space, the method characterized by the steps of: maintaining in a first structure (90) with respect to each of a subset of resource managers (21) the completion state (120) of its recovery responsibility with respect to each interrupted work unit (36), the completion state defining whether or not the resource manager has been restarted and, if restarted, the availability of the subset of resource collections required to complete the work unit; and maintaining in a second structure (70) with respect to each of said subset of said resource managers (21) (1) its operational state (82) and (2) the relative byte addresses in said recovery log of the beginning (84) and ending (80) of its interest scope.
Claim 3
Dependent Claim
154 words
The method of claim 1, further characterized by the steps of: restarting a plurality of resource managers following an interruption by (1) reestablishing during a current status phase the state of the resource collections managed by each resource manager being restarted, starting with the most recent checkpointed state advanced by subsequent records of changes in the log to the point of interruption; (2) for each resource manager being restarted, extending during a forward recovery phase the state of resource collections it manages to include the information from records of changes within its interest scope; exclusively reallocating resource collections to work units interrupted while in a commit-in-doubt state; and externalizing the most recent committed resource state of work units interrupted after a new point of consistency has been committed; and (3) for each resource manager being restarted, restoring during a backward recovery phase the resource collections altered by interrupted work units between points of consistency.
Claim 4
Dependent Claim
131 words
Method of claims 1 and 2 for restarting a computing system following termination, the computing system including a plurality of recoverable resources, a plurality of resource managers, and non-volatile storage on which to record a log of checkpoint states and images of changes made on behalf of work units to recoverable resources, the improved method characterized by the steps of: recording in a first data structure means (90) for an interrupted work unit its log activity scope and the recovery responsibilities of said resource managers; recording in a second data structure (70) for each resource manager its operational state and its log scope of interest; and responsive to information recorded in said first and second data structures, restarting selected resource managers following termination while deferring the restarting of other resource managers.
Claim 5
Dependent Claim
145 words
Apparatus for restarting a computing system following termination, the computing system (20) including a plurality of recoverable resources (44), a plurality of resource managers (21), and non-volatile storage (42) on which to record a log of checkpoint states and images of changes made on behalf of work units (36) to recoverable resources (44), the improved apparatus characterized by: first data structure means (90) for recording for an interrupted work unit (36) its log activity scope and the recovery responsibilities of said resource managers; second data structure means (70) for recording for each resource manager its operational state and its log scope of interest; and recovery means (28) responsive to information recorded in said first and second data structures for warm and cold restarting of selected resource managers following termination and for deferring the restarting of other resource managers or resources managed by restarting resource managers.
Claim 6
Dependent Claim
145 words
Apparatus for restarting a computing system following termination, the computing system (20) including a plurality of recoverable resources (44), a plurality of resource managers (21), and non-volatile storage (42) on which to record a log of checkpoint states and images of changes made on behalf of work units (36) to recoverable resources (44), the improved apparatus characterized by: first data structure means (90) for recording for an interrupted work unit (36) its log activity scope and the recovery responsibilities of said resource managers; second data structure means (70) for recording for each resource manager its operational state and its log scope of interest; and recovery means (28) responsive to information recorded in said first and second data structures for warm and cold restarting of selected resource managers following termination and for deferring the restarting of other resource managers or resources managed by restarting resource managers.
Claim 7
Dependent Claim
51 words
The apparatus of claim 4 wherein said recovery means further includes means (94, 96) for periodically recording on non-volatile storage (40, 42) a copy of the first data structure. when, at the conclusion (136) of a restart operation, the recovery responsibilities of at least one resource manager have not been completed.
Claim 8
Dependent Claim
33 words
The apparatus of claim 5 wherein said recovery means further includes means (71-73) for periodically recording on non-volatile storage (40, 42) a copy of said second data structure means and of changes thereto.
Claim 9
Dependent Claim
31 words
The apparatus of claim 6 wherein said recovery means further includes means for reading log records during a recovery operation to build from information therein said first data structure (fig. 7).
Claim 10
Dependent Claim
54 words
The apparatus of claim 7 wherein said recovery means further includes means for reestablishing during a current status phase the state of recoverable resources managed by each resource manager being restarted, starting with the most recent checkpointed state advanced by subsequent records of changes in the log to the point of interruption (fig. 7).
Claim 11
Dependent Claim
86 words
The apparatus of claim 8 wherein said recovery means further includes means for extending during a forward recovery phase for each resource manager being restarted the state of the resources it manages to include the information for records of changes within its scope of interest, for exclusively reallocating resources to work units interrupted while in a commit-in-doubt state, and for externalizing to said non-volatile storage the most recent committed resource state of work units interrupted after a new point of consistency has been committed (fig. 7).
Claim 12
Dependent Claim
41 words
The apparatus of claim 9 wherein said recovery means further includes means for restoring during a backward recovery phase the resource collections altered by each resource manager being restarted on behalf of interrupted work units between points of consistency (fig. 7).
References Cited (Backward Citations)
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