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US5537574A
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Sysplex shared data coherency method
Assignee: International Business Machines Corp
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Filing: 1992-03-30
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Granted: 1996-07-16
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Expires: 2012-03-30
Abstract
Abstract A method for controlling coherence of data elements sharable among a plurality of independently-operating CPCs (central processing complexes) in a multi-system complex (called a parallel sysplex) which contains sysplex DASDds (direct access storage devices) and a high-speed SES (shared electronic storage) facility. Sysplex shared data elements are stored in the sysplex DASD under a unique sysplex data element name, which is used for sysplex coherence control. Any CPC may copy any sysplex data element into a local cache buffers (LCB) in the CPC's main storage, where it has an associated sysplex validity bit. The copying CPC executes a sysplex coherence registration command which requests a SES processor to verify that the data element name already exists in the SES cache, and to store the name of the data element in a SES cache entry if found in the SES cache. Importantly, the registration command communicates to SES the CPC location of the validity bit for the LCB containing that data element copy. Each time another copy of the data element is stored in any CPC LCB, a registration command is executed to store the location of that copy's CPC validity bit into a local cache register (LCR) associated with its data element name. In this manner, each LCR accumulates all CPC locations for all LCB validity bits for all valid copies of the associated data element in the sysplex -- for maintaining data coherency throughout the sysplex.
Inventors
- 👤 David A. Elko
- 👤 Jeffrey A. Frey
- 👤 John F. Isenberg, Jr.
- 👤 Chandrasekaran Mohan
- 👤 Inderpal S. Narang
- 👤 Jeffrey M. Nick
- 👤 Jimmy P. Strickland
- 👤 Michael D. Swanson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:05
CPC Classifications
G; G06; G06F; G06F9/00; G06F9/06; G06F9/46; G06F9/52; G06F12/00; G06F12/02; G06F12/08; G06F12/0802; G06F12/0806; G06F12/0811; G06F12/0815; G06F12/084; G06F12/0866
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
294 words
A method of controlling data coherence for a computer multi-system complex, comprising the steps of structuring the computer multi-system complex as a sysplex which includes a plurality of central processor complexes (CPCs), sysplex direct access storage devices (DASDs) connected to the CPCs for storing data elements permanently in the sysplex, and a shared electronic storage (SES) attached to the CPCs, command issuers which execute in the CPCs to issue commands to the SES, said SES containing a SES cache with a SES cache directory for storing names of the data elements, the same data element name being used throughout the sysplex to identify all copies of the same data element stored anywhere in the sysplex whether or not any data element copy is changed relative to the data element or any copy of the data element, communicating a registration command to the SES by a command issuer in a CPC for providing a data element name and associated CPC location information for locating in the CPC a validation indication associated with a data element copy stored in a local LCB in the CPC, the registration command controlling SES to register the data element copy for the SES cache, registering the associated CPC location information in a local cache register (LCR) associated with a SES cache directory entry storing the data element name in the SES cache directory in response to the communicating step, and accumulating all CPC location information in the LCR for all registration commands received for the same SES cache entry containing the data element name for locating all validation indicators for all copies of the data element in all connected CPCs in the sysplex for enabling coherence control for the copies of the data element among the CPCs in the sysplex.
Claim 2
Independent Claim
294 words
A method of controlling data coherence for a computer multi-system complex, comprising the steps of structuring the computer multi-system complex as a sysplex which includes a plurality of central processor complexes (CPCs), sysplex direct access storage devices (DASDs) connected to the CPCs for storing data elements permanently in the sysplex, and a shared electronic storage (SES) attached to the CPCs, command issuers which execute in the CPCs to issue commands to the SES, said SES containing a SES cache with a SES cache directory for storing names of the data elements, the same data element name being used throughout the sysplex to identify all copies of the same data element stored anywhere in the sysplex whether or not any data element copy is changed relative to the data element or any copy of the data element, communicating a registration command to the SES by a command issuer in a CPC for providing a data element name and associated CPC location information for locating in the CPC a validation indication associated with a data element copy stored in a local LCB in the CPC, the registration command controlling SES to register the data element copy for the SES cache, registering the associated CPC location information in a local cache register (LCR) associated with a SES cache directory entry storing the data element name in the SES cache directory in response to the communicating step, and accumulating all CPC location information in the LCR for all registration commands received for the same SES cache entry containing the data element name for locating all validation indicators for all copies of the data element in all connected CPCs in the sysplex for enabling coherence control for the copies of the data element among the CPCs in the sysplex.
Claim 3
Dependent Claim
105 words
A method of controlling data coherence For a computer multi-system complex as defined in claim 1, further comprising the step of performing in the SES cache a name replacement operation which is communicating a data element name and associated CPC location information for a copy of a data element to be deregistered, finding any SES directory entry having the data element name, matching the communicated CPC location information with CPC location information in the LCR associated with the directory entry, and deleting any CPC location information found in the LCR that matches the communicated CPC location information to deregister the copy of the data element.
Claim 4
Dependent Claim
69 words
A method of controlling data coherence for a computer multi-system complex as defined in claim 1, further comprising the steps of: performing in the SES cache a re-registration operation which is communicating a data element name and associated CPC location information to be registered, finding a SES directory entry having the data element name, and replacing the currently registered associated CPC location information with the communicated CPC location information.
Claim 5
Dependent Claim
59 words
A method of controlling data coherence for a computer multi-system complex as defined in claim 1, further comprising the steps of issuing by a CPC to SES a read command for requesting registration of a data element in the SES cache, and requesting reading of a data element sent from the CPC to SES with a data element name.
Claim 6
Dependent Claim
59 words
A method of controlling data coherence for a computer multi-system complex as defined in claim 1, the registering step further comprising registering with the SES cache directory entry in the associated LCR the CPC location information for the invalidation request bit associated with the LCB containing the copy of the data item which is subject to a registration command.
Claim 7
Dependent Claim
68 words
A method of controlling data coherence for a computer multi-system complex as defined in claim 1, the registering step further comprising assigning into the SES cache directory entry of a data element name for a copy of a data element located in an LCB in response to a request from a CPC when the data element name is not found in any entry in the SES cache directory.
Claim 8
Dependent Claim
85 words
A method of controlling data coherence for a computer multi-system complex as defined in claim 5, further comprising the steps of issuing by a CPC to SES a command providing a name of a data to request invalidation of the content of all LCB(s) in the CPCs in the sysplex currently having a copy of the data element and SES responding to the CPC issuing the command with a completion signal when all invalidation signalling by SES to the CPCs is completed for the command.
Claim 9
Dependent Claim
88 words
A method of controlling data coherence for a computer multi-system complex as defined in claim 7, further comprising the steps of issuing by a command issuer in a CPC to SES a command providing a name of a data element to request invalidation of the content of all LCB(s) in the sysplex currently having the name in a SES cache directory entry found to be associated with the name except not requesting invalidation of the copy of the data element in the LCB associated with the command issuer.
Claim 10
Dependent Claim
226 words
A method of controlling data coherence for a computer multi-system complex as defined in claim 1, further comprising the steps of designating for each local cache (LC) in each CPC a set of invalidation request bits, each LC containing one or more LCBs, each invalidation request bit being associated with a respective LCB, locatinq the LCR associated with the SES cache directory entry containing the data element name readinq the associated CPC location information in the LCR for determining the locations of all invalidation request bits for all conflicting copies of the data element in all LCBs in all CPCs in the sysplex in response to a command issuer sending to SES a command that requires a determination of conflicting copies of the data element, determining each CPC indicated by the associated CPC location information read from the LCR to locate an invalidation request bit for each conflicting copy of the data element, signalling by the SES the associated CPC location information Of the LCR to each CPC determined by the determining step to locate each invalidation request bit for each conflicting copy of the data element in any LCB in any CPC in the sysplex, and requesting by the signalling step each determined CPC to set to an invalidation state each invalidation request bit located by the signalled CPC location information received by the CPC.
Claim 11
Dependent Claim
74 words
A method of controlling data coherence for a computer multi-system complex as defined in claim 9, further comprising the steps of controlling by a program in a CPC the setting and testing of states of the invalidation request bits associated with LCBs of that CPC, and invalidating by the program of a copy of a data element in an LCB for which the program tests an invalidation state for an associated invalidation request bit.
Claim 12
Dependent Claim
42 words
A method of controlling data coherence for a computer multi-system complex as defined in claim 10, further comprising the steps of executing in a CPC an instruction to determine a current state for an invalidation request bit assigned to a specified LCB.
Claim 13
Dependent Claim
81 words
A method of controlling data coherence for a computer multi-system complex as defined in claim 10, further comprising the steps of executing an instruction by CPC operating software to set to a valid state an invalidation request bit assigned to a specified LCB value for a specified LC, transmitting by the CPC to SES a registration command, and setting in the CPC the invalidation request bit to an invalid state if the registration command does not perform a registration in SES.
Claim 14
Dependent Claim
65 words
A method of controlling data coherence for a computer multi-system complex as defined in claim 1, further comprising the steps of issuing by a CPC to SES a write command for requesting registration of a copy of a data element in the SES cache, and requesting writing of the copy of the data element sent from the CPC to SES with a data element name.
Claim 15
Dependent Claim
94 words
A method of controlling data coherence for a computer multi-system complex as defined in claim 13, further comprising the steps of issuing by a CPC to SES a write command which sends a data element to SES with a data element name, and performing a write operation by writing the data element in a SES cache data area only if the data element name is found in a directory entry in the SES cache, and CPC location information for the copy in the CPC is found in the LCR associated with the directory entry.
Claim 16
Dependent Claim
104 words
A method of controlling data coherence for a computer multi-system complex as defined in claim 13, further comprising the steps of sending with the write command a change indication to be stored in the directory entry, where a first value for the change indication indicates the sent copy of the data element is not changed from a version of the same data element stored in a sysplex DASD or SES, and where a second value for the change indication indicates the sent copy of the data element is changed from a version of the same data element stored in a sysplex DASD or SES.
Claim 17
Dependent Claim
56 words
A method of controlling data coherence for a computer multi-system complex as defined in claim 15, further comprising the steps of responding by SES to the CPC issuing the command with SES refusing to write the data element in an unchanged state when the SES directory entry indicates a changed state for a SES-stored data element.
Claim 18
Dependent Claim
86 words
A method of controlling data coherence for a computer multi-system complex as defined in claim 15, further comprising the steps of writing the data element in a SES data area associated with the SES cache entry containing the data element name, and p1 signalling an invalidation request by SES to each CPC having an LCB(s) with a complement copy of the data element as identified by CPC location information associated with the SES cache directory entry which indicates a changed data element is stored in SES.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-07-16 | 2000-01-15 | 2000-07-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-07-16 | 2004-01-15 | 2004-07-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-07-16 | 2008-01-15 | 2008-07-16 | $7700.00 | Window Closed / Lapsed |