Abstract: A method and apparatus for providing a recent set of replicas for a cluster data resource within a cluster having a plurality of nodes. Each of the nodes having a group services client with membership and voting services. The method of the present invention concerns broadcasting a data resource open request to the nodes of the cluster, determining a recent replica of the cluster data resource among the nodes, and distributing the recent replica to the nodes of the cluster. The apparatus of the present invention is for providing a recent set of replicas for a cluster data resource. The apparatus has a cluster having a plurality of nodes in a peer relationship, each node has an electronic memory for storing a local replica of the cluster data resource. A group services client, which is executable by each node of the cluster, has cluster broadcasting and cluster voting capability.

Abstract: A method and apparatus for providing a recent set of replicas for a cluster data resource within a cluster having a plurality of nodes; each of the nodes having a group services client with membership and voting services. The method broadcasts a data resource open request to the nodes of the cluster, determines a recent replica of the cluster data resource among the nodes, and distributes the recent replica to the nodes of the cluster. The apparatus is for providing a recent set of replicas for a cluster data resource. The apparatus has a cluster having a plurality of nodes in a peer relationship; each node has an electronic memory for storing a local replica of the cluster data resource. A group services client, which is executable by each node of the cluster, has cluster broadcasting and cluster voting capability.

Abstract: Within a computer cluster usage reference counts are maintained for replicated databases within a computer cluster using cluster membership and cluster voting services. Such a method includes the maintaining of a local reference count for all open distributed data resources within a given node, tracking by a group services client of those nodes that have the open distributed data resources, and using cluster membership services to update the local reference counts for node failures.

Abstract: A method for replicating data in a distributed computer environment wherein a plurality of servers are configured about one or more central hubs in a hub and spoke arrangement. In each of a plurality of originating nodes, updates and associated origination sequence numbers are sent to the central hub. The hub sends updates and associated distribution sequence numbers to the plurality of originating nodes. The hub tracks acknowledgments sent by nodes for a destination sequence number acknowledged by all nodes. Thereafter, a highest origination sequence number is sent from the central hub back to each originating node.

Abstract: A method of replacing a current version of a program module with a replacement version of the module concurrently with the execution of the program on a computer system. For each entry point within the current version of said module to which the program may make address reference, a corresponding entry point within the replacement version of the module is determined. While execution of the program is suspended, each address reference in the program to an entry point within the current version of the module is replaced with an address reference to the corresponding entry point within the replacement version of the module. Execution of the program is resumed when each address reference to the current module has been replaced with one to the replacement module.

Abstract: A method for replicating data in a distributed computer environment wherein a plurality of servers are configured about one or more central hubs in a hub and spoke arrangement. In each of a plurality of originating nodes, updates and associated origination sequence numbers are sent to the central hub. The hub sends updates and associated distribution sequence numbers to the plurality of originating nodes. The hub tracks acknowledgments sent by nodes for a destination sequence number acknowledged by all nodes. Thereafter, a highest origination sequence number is sent from the central hub back to each originating node.

Abstract: A node failure recovery mechanism for use in a data replicating system in a distributed computer environment wherein a plurality of servers are configured about one or more central hubs in a hub and spoke arrangement. In each of a plurality of originating nodes, updates and associated origination sequence numbers are sent to the central hub. The hub sends updates and associated distribution sequence numbers to the plurality of originating nodes. The hub tracks acknowledgments sent by nodes for a destination sequence number acknowledged by all nodes. Upon failure of a node, a node failure recovery method may be used to enable a “buddy” node to help the failed node gain readmission to a distribution group.

Abstract: A method for replicating data in a distributed computer environment wherein a plurality of servers are configured about one or more central hubs in a hub and spoke arrangement. In each of a plurality of originating nodes, updates and associated origination sequence numbers are sent to the central hub. The hub sends updates and associated distribution sequence numbers to the plurality of originating nodes. The hub tracks acknowledgments sent by nodes for a destination sequence number acknowledged by all nodes. Thereafter, a highest origination sequence number is sent from the central hub back to each originating node.

Abstract: A method of scheduling jobs to be executed by a resource in a computer system wherein the jobs are grouped in “classes.” The job classes vying for the resource's attention are arranged in a hierarchy. Each job class has a time-function value that controls when the job class is selected by the resource if processing time becomes available. Within a particular level of the hierarchy, scheduling priorities are defined by one or more time-based functions, each of which may be constant or dynamically varying. When constant time-based functions are used, each job class has a schedule value that remains fixed with time. When dynamic time-based functions are used, job class “time-function values” are modified to alter the timing by which the job class(es) acquire the resource.

Abstract: A dynamic reconfiguration request for a change in a system's physical configuration is transmitted from a configuration controller to a hypervisor controlling operating systems executing in one or more partitions of the system. The hypervisor translates the physical reconfiguration request into a request for reconfiguration of logical resources known to the operating systems, first verifying it against an installation policy, and passes the requests to the operating systems in the partitions. The operating systems perform logical reconfiguration, then request physical reconfiguration of the hypervisor. The hypervisor initiates the physical reconfiguration through the configuration controller.