EP0096199A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and apparatus for logging journal data in a computing apparatus
Assignee: International Business Machines Corp
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Filing: 1983-04-20
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Granted: —
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Expires: 2003-04-20
Abstract
Abstract Operation of a computing system including a data base and a log of changes to the data base is enhanced by enabling online access to log records stored both in direct access storage devices and archive log storage devices. Responsive to a request from a user of a log facility to store a log record, a sequential relative byte address is assigned to the log record and returned to the user, and the log record is stored in a main storage log buffer. The log buffer contents are periodically written to one of at least two data sets on direct access storage devices, and these data sets are offloaded selectively from the direct access storage device to an archive log device while writes of log buffer contents to the data set being offloaded are inhibited. An index of the log records is maintained in a boot strap data set, and includes the range of relative byte addresses of log records stored in each direct access storage device and archive device. Responsive to a request from a user of the log facility for a log record having a given relative byte address, the requested log record is obtained from the most accessible storage location referenced by the index.
Inventors
- 👤 Clifford Mellow
- 👤 Jimmy Paul Strickland
- 👤 Edward Erland Sundell
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 04:37
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/14; G06F11/1471; G06F16/00
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
215 words
A method for operating a computing apparatus to enhance the operation of the computing apparatus during recovery from failure, the apparatus including buffer means, storage device means including direct access storage device means and archival storage device means, and program execution means, the method executed under control of said program execution means including the steps of writing log records to said storage device means, said log records including records of changes to a data base and of changes to the state of a system including said computing apparatus, the improved method characterized by the steps of: assigning to each log record a relative byte address within a continuous address space; storing said log record in said buffer means; writing the contents of said buffer means to an active data set on said direct access storage device means; offloading said active data set to an archive data set on said archival storage device means; maintaining an index of the relative byte addresses of log records in each active and archive data set; and responsive to a request specifying the relative byte address of a desired log record, obtaining said desired log record from the first of said buffer means, said direct access storage device means, or said archival storage device means in which it currently resides.
Claim 2
Independent Claim
215 words
A method for operating a computing apparatus to enhance the operation of the computing apparatus during recovery from failure, the apparatus including buffer means, storage device means including direct access storage device means and archival storage device means, and program execution means, the method executed under control of said program execution means including the steps of writing log records to said storage device means, said log records including records of changes to a data base and of changes to the state of a system including said computing apparatus, the improved method characterized by the steps of: assigning to each log record a relative byte address within a continuous address space; storing said log record in said buffer means; writing the contents of said buffer means to an active data set on said direct access storage device means; offloading said active data set to an archive data set on said archival storage device means; maintaining an index of the relative byte addresses of log records in each active and archive data set; and responsive to a request specifying the relative byte address of a desired log record, obtaining said desired log record from the first of said buffer means, said direct access storage device means, or said archival storage device means in which it currently resides.
Claim 3
Dependent Claim
54 words
The method of claim 1 further characterized by the step of writing the contents of said buffer means to an active data set selectively upon the filling of said buffer means with log records or upon expiration of a predetermined time since the last writing of said buffer means to an active data set.
Claim 4
Dependent Claim
29 words
The method of claim 1 further characterized by the step of offloading an active data set to an archive data set upon the filling of an active data set.
Claim 5
Dependent Claim
24 words
The method of claim 1 further characterized by maintaining a plurality of copies of said log records in different active and archive data sets.
Claim 6
Dependent Claim
95 words
The method of claim 1 wherein said obtaining step is further characterized by the steps of: searching said buffer means for the desired log record; and if not found searching said index to identify an active data set containing said desired log record and, if found, loading the desired log record into a read buffer in main storage from the active data set; otherwise, searching said index to identify an archival data set containing said desired log record and, if found, loading the desired log record into said read buffer from the archival data set.
Claim 7
Dependent Claim
26 words
The method of claim 1 further comprising the step of writing a log record as a spanned record into a plurality of active log data sets.
Claim 8
Dependent Claim
92 words
A computing apparatus including program execution means, buffer means, storage device means including direct access storage device means and archival storage device means, said program execution means being operable to control the writing of log records to said buffer means and thence to said storage device means, and a program executable by said program execution means which assigns to each log record a unique relative byte address within a continuous address space, the continuous address space including each of said buffer means, direct access storage device means, and archival storage device means.
Claim 9
Dependent Claim
92 words
A computing apparatus including program execution means, buffer means, storage device means including direct access storage device means and archival storage device means, said program execution means being operable to control the writing of log records to said buffer means and thence to said storage device means, and a program executable by said program execution means which assigns to each log record a unique relative byte address within a continuous address space, the continuous address space including each of said buffer means, direct access storage device means, and archival storage device means.
Claim 10
Dependent Claim
100 words
The computing apparatus of claim 7 in which the program causes said program execution means to periodically write the contents of said buffer means an active log data set on said direct access storage device means, to periodically offload said active log data set to an archival data set on said archival storage device means, and responsive to a request specifying the relative byte address of a desired log record obtains said desired log record from the first of said buffer means, direct access storage device means, or archival storage device means in which said desired log record is located.
References Cited (Backward Citations)
No citation records indexed.
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