The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 03, 2003
Filed:
Jun. 24, 1996
Charles Simmons, San Mateo, CA (US);
Madhusudan Krishnapuram, Mountain View, CA (US);
Hans Karten, Ermelo, NL;
Oracle Corporation, Redwood Shores, CA (US);
Abstract
A method and system for managing locks that give permission to access resources in a computer system are disclosed. The lock management system is distributed and provides deadlock protection. The lock management system is distributed in that information about which locks have been granted for a resource is stored at both a master node and at the nodes on which are located the processes that desired to access the resource. A master resource object located on the master node grants locks to shadow resource objects located on the nodes on which are located the processes that desire to access the resource. Each shadow resource object grants locks on the resource to the processes that are located on the same node as the shadow resource object. The lock owned by the shadow resource object determines the types of locks the shadow resource object is allowed to grant to processes. If the lock owned by a shadow resource object does not give the shadow resource object the right to grant a lock requested by a process, then the shadow resource object requests for a lock upgrade from the master resource object. Because the processes that use a resource do not have to communicate directly with the master resource object, the amount of inter-node traffic required by the distributed lock management system is less than that required by centralized, non-distributed lock management systems.