Electrical computers and digital data processing systems: input/ – Access locking
Reexamination Certificate
2007-07-17
2007-07-17
Portka, Gary (Department: 2188)
Electrical computers and digital data processing systems: input/
Access locking
C711S152000, C711S163000
Reexamination Certificate
active
10955033
ABSTRACT:
A method for controlling exclusive access to a resource shared by multiple processors in a data storage system includes providing a system lock procedure to permit a processor to obtain a lock on the shared resource preventing other processors from accessing the shared resource and providing a faked lock procedure to indicate to the system lock procedure that a processor has a lock on the shared resource where such a lock does not exist, and wherein the faked lock procedure prevents another processor from obtaining the lock on the shared resource, but does not prevent other processors from accessing the shared resource. A data storage system according to the invention includes a shared resource, a plurality of processors coupled to the shared resource through a communication channel, and a lock services procedure providing the system lock procedure and the faked lock procedure. In one embodiment, the shared resource is a cache and the system lock procedure permits a processor to lock the entire cache whereas the faked lock procedure is implemented by a processor seeking exclusive access of a cache slot.
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Ezra Josef
Ofer Adi
Daly, Crowley & Mofford & Durkee, LLP
EMC Corporation
Portka Gary
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