International Business Machines Corporation

Robert Bradley Bennett

Eugene Johnson

Edward Joseph Bendert

James M Showalter

Thomas J Szczygielski

Cherie C Barnes

Robert Michael Nugent

Michael K Ainsworth

Barbara A Maslak

Amos S Tanner

Joseph M Gdaniec

Andrew Coleman

Susan Marie Farrell

Robert C Will

Robert J Catino

Edmond A Pruul

Mary E Vendryes

Terrence Lee Woodnorth

Janet E Geddes

Robert Micheal Nugent

Eve Suzanne Berman

Brian Paul Dixon

Wendy E Stephens

A method and system for constructing rule-based intelligent agents that process events on behalf of one or more users. The intelligent agents have event-generating modules that supply events to be processed, and event-processing modules that process the events by evaluating rules. Each event-processing module of the agent includes multiple sets of rules, one or more such sets for each user of the agent. A selection key related to the user is associated with a rule set, and for event-generating modules a selection key indicates the user on whose behalf the event was generated. When the event-processing module receives an event with a selection key, the module locates and evaluates the rule set(s) which have a matching key to launch the corresponding actions. Addition, replacement or removal of rule sets for a user is made by temporarily suspending the initiation of new events for the user designated by the rule set's selection key; completing all in-progress events for that user; effecting the modification to the rule set within the event-processing modules; and the resuming the initiation and processing of events for the user. While the rule sets are being modified for a particular user, event generating and processing continues unimpeded for the other users of the agent.

Method and system for managing rules and events in a multi-user intelligent agent environment

Selected server operations that affect objects in a distributed computing system can be off-loaded from servers at which the objects are stored to other servers without the requirement of vertical partitioning of the affected objects and without off-loading entire affected objects. A client environment process that requests an operation on an object is notified of a task server to which selected off-load operations should be sent. The client preferably stores the task server identifier and thereafter sends such operation request directly to the identified task server. The object metadata information can be stored in the client environment, if desired. The object metadata at the owning repository server is maintained, if affected by the requested operation. A single task server can perform off-loaded functions from several other repository servers at the same node and at other nodes, and in that way reduce the workload of many servers. The functions that can be off-loaded include named pipe functions and byte range file lock operations.

Operation-partitioned off-loading of operations in a distributed environment

A client-server distributed computer processing system provides staged byte range locking with three levels of lock complexity and contention. When locking activity for a data object involves a plurality of clients, locking is managed centrally in the server operating environment. When only a single client is involved in requesting a lock on a data object such as a data file or portion of a data file, the requesting client can be permitted to manage the locking locally in the requesting client operating environment. Client-managed locking involves two stages of locking complexity on an object-by-object basis. The first stage of client locking involves only a log of current lock activity and handles relatively simple locking. When locking becomes more complex, the client locking is migrated to a second local locking stage, where more complex data structures can support lock fragmentations that affect various portions of the data object, such as partially overlapped byte ranges. Migration between the three stages of locking uses a high level interface rather than migrating implementation-dependant structures and thereby avoids implementation dependencies and local optimization restrictions. The three-stage locking scheme optimizes performance for the more common cases of lock management, where there is minimal contention and less complexity or overlap in locking scope.

Byte range locking in a distributed environment

A client/server computer system manages shared files. A client includes a data cache and an associated cache manager, and executes a client application that requests data from a shared file. In response to the request, the client cache manager determines if the data is currently stored in the data cache, and if so, grants the client access to the data in the cache. However, if the data is not currently stored in the cache, the client cache manager sends to the server a request for multiple consecutive blocks of data beginning with the first block containing the data requested by the client from the shared file. The server includes a token manager which receives the request, and in response (a) awards the token for a first data block specified in the request regardless of contention for the first data block and (b) awards tokens for all other consecutive blocks following the first block of the multiple blocks held by a client who also holds the token for the first block. However, if another client currently holds a contending token for one of the consecutive blocks other than the first block but does not also hold the token for the first block, then the token management process awards only the tokens for the first block and all blocks between the first block and the one block.

System for awarding token to client for accessing first data block

A system and method efficiently manage clones of an object group. A base storage area contains metadata for each of multiple objects in the object group. The metadata for each object identifies data within each object. The system receives a request to clone a base storage area, and in response, the system creates a clone storage area containing an identification of the base storage area but not the metadata. If there is a subsequent request to update a portion of one of the objects, then the system copies the portion, copies the metadata into the clone storage area for the one object, makes the update to the object copy and changes the metadata in the base storage area to identify the portion copy instead of the original portion. If there is no subsequent request to update any of the multiplicity of objects, then the system does not copy the metadata for any of the multiplicity of objects into the clone storage area.

Creation of clone storage area with identification of base storage area

A method of and system for optimizing process utilization in a shared resource environment that avoids holding system processes while requests are queued or waiting for system resources. Information about a waiting request is retained in control structures; then the same process that frees a resource is utilized to respond to queued requests for that resource. The effect is to minimize the retention and/or allocation of processes and their associated system resource requirements. The same method is applied to the synchronization of interprocess communications.

Method for controlling the locking and unlocking of system resources in

A computer system manages first and second different file systems. The system comprises first and second, different file managers having first and second different APIs for the first and second file systems, respectively. The system also comprises a hybrid file manager for managing the second file system based on requests made using the first API. The hybrid manager applies rules from both APIs to control atomicity of requests, access concurrency, and data consistency rules. The hybrid rules prevent violation of the rules of either API.

Heterogeneous filing system with common API and reconciled file

A file management and backup system manages access to data objects such as records stored in a primary repository, and occasionally backs-up the data objects to a backup repository. A backup utility within the system, periodically or at the request of a user, makes a backup request to a file manager, and specifies the scope of the backup. In response, the file manager makes an entry in a 'backup in progress' table indicating that the corresponding file space(s), directory(ies), file(s) and/or data object(s) are currently involved in a consistent backup procedure. Then, the backup utility commences the actual copying of the data within the backup scope to the backup repository with assistance from the file manager in accessing the data from the primary repository. If a request is made to update a file space, directory, file or data object within the backup scope once the entry is made in the backup in progress table, the file manager makes a 'shadow' or copy of the file space, directory, file or data object for which update is requested. Then, the file manager updates the original file space, directory, file or data object, and uses the shadow copy for the backup procedure. After the backup is completed, the shadow copy is invalidated. If the update request is made during the backup procedure to a directory, file or data object which has already been backed-up, then a shadow copy is not necessary.

Computer file management and backup system

A computer network comprises first and second computers, each having a recovery facility for recovering a two-phase commit procedure and a recovery log. The log comprises a log name log which stores the names of other logs involved in a commit scope and a sync point log which stores sync point phase information. The log names are exchanged prior to a request for sync point. If a failure occurs during sync point, each recovery facility in the commit scope again exchanges log names to verify that there was not a log failure since the prior exchange. Absent a log failure, the logs are used to recover from the sync point failure. Communication facilities are interposed between the first and second computers and include log name exchange tables which record the previous exchanges of log names between the first and second computers. If a protected conversation is initialized from the first computer to the second computer and log names were not previously exchanged, then the communication facilities intercept the conversation and hold it until log names are exchanged.

Log name exchange for recovery of protected resources

In a computer system or process, sync point managers are distributed throughout each real machine for a plurality of execution environments, but all of the execution environments and sync point managers within one real machine share a common recovery facility and recovery log. A common recovery log is used by the recovery facility for all of the execution environments in the system. Different systems are interconnected by a communication facility and each has its own recovery facility and recovery log. A protected conversation can be initiated between the first and second execution environments in the same real machine, and the sync point managers within the respective execution environments coordinate the two-phase commit procedures associated with the protected conversations. A conversation manager within each real machine assists in routing the conversation between the first and second execution environments. Each resource manager, whether residing inside or outside of the real machine, has its own recovery log, but uses the recovery facility of the real machine that accesses the resource.

Coordinated sync point management of protected resources

To recover a failed commit procedure, a first recovery facility collects and compares sync point state information from a variety of different types of resources including a data repository and a protected conversation. The comparison of the sync point state information is made automatically in response to a sync point failure event. A second recovery facility serving another execution environment notifies the first recovery facility after a failure and subsequent recovery procedure of the second execution environment has completed. The first recovery facility makes automatic cyclic attempts to communicate with the second recovery facility. The first recovery facility can receive a manually initiated but automatically simulated response of sync point state information when there is a failure such that actual sync point state information cannot be received. The first recovery facility is responsive to the simulated sync point state information to proceed with a recovery operation substantially as if actual sync point state information were received.

Recovery facility for incomplete sync points for distributed application

A computer system manages storage of files and/or directories. The computer system stores a specification of a file space allocation for an application support processor, an application program, or a group of application programs. The computer system can store temporary files for the application support processor, application program or group of application programs that require greater file space than the file space allocation. This is done by temporarily providing extra unused file space during processing of the temporary files. When the application support processor, application program or group of application programs attempts to commit the files, the file space allocation is enforced. The computer system can store specifications of file space allocations for a plurality of other application support processors, application programs or groups of application programs. The computer system supports a situation where the temporary files for the first application support processor, application program or a group of application programs requires so much file space beyond the allocation for the first application support processor, application program or group of application programs that all of the allocations cannot be satisfied at the time these temporary files are stored.

File management system for a computer

A Data Access System for a File Access Processor for servicing requests from a set of Application Support Processors, which can exist in a global network, with each Application Support Processor sharing access to data in files stored by the File Access Processor. The File Access Processor manages access to a set of data files and information about files held in file directories, which allow for managing file collections, can relate to each other hierarchically, and may be shared. Each Application Support Processor also maintains therein an internal cache of file information to improve performance by reducing communications required with the File Access Processor for information about files. The File Access Processor provides the Application Support Processors with information for updating and maintenance of local caches of directory and file description information through a centralized accumulation and distribution of cache change notifications. The Data Access System also provides for permanent storage in the form of catalogs for retaining shared information about files, directories, and control information. A separate access method and storage facility is utilized for these catalogs from that utilized for file data, permitting flexibility in access to catalog information which require access only occasionally, while retaining high performance in the access to file data.

Data access system for a file access processor

A file sharing system, comprising a file access processor and a plurality of application support processors; and the file access processor, in turn, includes a central data access system and a storage system is provided to form directories from data in the database, and to change data in that database. Each support processor includes a local cache to acquire and hold directories formed by the data access system; and for each directory acquired by at least one support processor, the data access system further includes a directory gate and a multitude of directory change blocks holding information describing changes in the database that affect the directory. The directory change blocks established for a given directory are arranged in a first chain anchored to the directory gate established for the directory. For each support processor that has acquired at least one directory, the data access system further includes a directory acquired block for each directory acquired by the support processor. Preferably, the directory acquired blocks established for a given directory are arranged in a second chain also anchored to the directory gate established for the given directory.

Local cache structure for maintaining updated file characteristics in a

A Space Management System for a Data Access System of a File Access Processor for servicing requests from a set of Application Support Processors, which can exist in a global network, with each Application Support Processor sharing access to data in files stored by the File access Processor. The File Access Processor manages access to a set of data files and information about files held in file directories, which allow for managing file collections, can relate to each other hierarchically, and may be shared. Each Application Support Processor also maintains therein an internal cache of file information to improve performance by reducing communications required with the File Access Processor for informatin about files. The File Access Processor provides the Application Support Processors with information for updating and maintenance of local caches of directory and file description information through a centralized accumulation and distribution of cache change notifications. The Space Management System manages file space assigned to each Application Support Processor and supports the space management functions of, adding space, deleting space, setting thresholds for limit warnings, querying space, charging space used, warning notifications, crediting space freed, and permitting file spaces to be shared by more than one application suppoort processor.

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Endwell, NY, United States of America

Robert Bradley Bennett