International Business Machines Corporation

Steven R Champagne

Rosario A Uceda-Sosa

Kailash N Marthi

Gregory D Laib

Marcos Nogueira Novaes

Felipe Knop

Myung Mun Bae

Robert K Gardner

Johannes Sayre

Peggy Catherine Zych

Gary J Nagelhout

Concurrent access to a global data repository is provided, while minimizing the number of locks acquired to provide the concurrent access. One or more resources within the global data repository have predefined relationships with one or more other resources of the repository. Thus, locking for a particular resource is based on its relationship with one or more other resources of the repository.

System and program products for efficiently locking resources of a global data repository

A method for managing node-specific quorum roles in a cluster of nodes. The method comprises assigning a configuration change of node role attributes to a node in the cluster, with each attribute being represented by a bit of a binary value. The binary value corresponding to the specified node role attributes is converted to an integer value and the integer value is stored in a node record associated with the node. The node record is accessed to isolate each bit of the integer value associated with the node and the node role attributes assigned to the node are identified from each of the isolated bits of the integer value associated with the node. A determination of whether the configuration change can be safely supported by a configuration quorum of nodes required to represent the cluster's configuration accurately is made based on the identified node role attributes. An additional determination of whether a required operational quorum of nodes permits access to critical and shared resources is made based on the identified node role attributes. Endorsement for the configuration change is sought from subsystems that may be affected by the configuration change. The identified node role attributes are propagated to other nodes within the cluster.

Method for managing cluster node-specific quorum roles

A method of providing a database of generic messages for diverse applications, includes examining an application for messages to be output to a user of the application, returning a found message from the examined application in a first language, determining if a generic message appropriate for the returned message is available in a generic message composing facility, appropriating an appropriate generic message from the generic message composing facility if it is determined that said generic message is available, providing an appropriate translation of the appropriated generic message in a second language if it is determined that said generic message is available, adding a translation of the returned message to the generic message composing facility if it is determined that said generic message is not available, and outputting the translated message to the application in the second language.

Generic message composing facility

Method for efficiently locking resources of a global data repository

A client application sends a request to a given server of a replicated group of servers, and expects a response to the request. If the client does not receive a response to the request, or if the server is otherwise unavailable, the client is automatically reconnected to another server of the replicated group. The servers of the replicated group do not, however, have to have any knowledge of the communication session of the client.

Method, system and program products for automatically connecting a client to a server of a replicated group of servers

At least a portion of a table stored in a global data repository is selected to be accessed and modified. The selected portion is stored in a local table in local memory of a node of a client-server environment. The local table is modified, and then at least a portion of the modified local table is merged with the global table. The merger is performed without requiring any user locking of the global table.

Method, system and program products for modifying globally stored tables of a client-server environment

One or more tables stored in a global data repository are concurrently accessible and modifiable. A client requests the locking of one or more tables within a global server data repository on behalf of a local tree. This locking creates a lock block, which enables at least a portion of the locked tables to be selected, modified and then merged back with the tables residing in the server. One or more other clients may also request to use the same lock block and thus, the same local tree, if shared concurrency is allowed. These other clients would also be allowed to select, modify and merge at least a portion of the tables. The merging of the tables is serialized at the global data repository, if necessary.

Method, system and program products for concurrent write access to a global data repository

Write requests are performed against one or more resources of a resource group in a persistent and atomic manner. When a write request is received, a backup resource group is updated to reflect data in a current resource group. Thereafter, the write request is performed against the backup resource group. After successfully performing the write operation(s), the backup resource group and the current resource group are swapped in an atomic, consistent manner, such that the backup resource group is now the new current resource group.

Method, system and program products for atomically and persistently swapping resource groups

A database management system for use in designing integrated circuit chips. A large number of designers and users are given concurrent access to design data stored in a Master Table by providing each designer with a private copy of the Master Table called the designer's Virtual Table. Each designer can independently alter data displayed from the designer's Virtual Table without interfering with other designers. Whenever a designer alters the displayed data, the displayed row containing the altered data is written to the Master Table and the designer's Virtual Table, provided that the Master Table row's time-date stamp matches the corresponding Virtual Table row's time-date stamp. If the time-date stamps do not match, then the Master Table row is copied into the Virtual Table, the designer receives an error message, and the designer is allowed to update the corrected row.

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Poughkeepsie, NY, United States of America

Steven R Champagne