System and method for controlling access to data shared by a plurality of processors using lock files
Patent 5566319 Issued on October 15, 1996. Estimated Expiration Date: 
October 15, 2013. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
October 15, 2013. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesMethod for lock management, page coherency, and asynchronous writing of changed pages to shared external store in a distributed computing system Access authorization table for multi-processor caches Patent #: 5230070 InventorApplicationNo. 058702 filed on 05/06/1993US Classes:711/147, Shared memory area700/5, Shared memory707/1, DATABASE OR FILE ACCESSING709/229, Network resources access controlling710/200, ACCESS LOCKING711/145, Access control bit711/150, Simultaneous access regulation711/152, Memory access blocking711/163Access limitingExaminersPrimary: Gossage, GlennAttorney, Agent or FirmForeign Patent References
International ClassesG06F 013/14G06F 013/00 Foreign Application Priority Data1992-05-06 EPAbstractA system and method for controlling access to data in storage which is shared by a plurality of processors are disclosed. The shared storage is located outside of main storage of each of the processors and stores a lock file. The lock file comprises a plurality of control fields containing access administration information (ZVI) authorizing the processors to access the data when not currently being accessed by another processor and a status identification code (SKC) to indicate the status of the access administration information. In response to a data access request from one of the processors, the status identification code provided by the processor is compared to the stored status identification code. If the comparison indicates that the requesting processor is authorized to update the access administration information, the access administration information associated with the requesting processor for the type of data access request is written from the requesting processor to the shared storage without first reading the stored access administration information from the lock file. The status identification code in the storage is updated to indicate that the processor has updated the access administration information.Other References
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