International Business Machines Corporation

Benjamin Mandler

Frank Bernhard Schmuck

Michael Edward Factor

Nir Naaman

James Christopher Wyllie

Gidon Gershinsky

Yoav Tock

Alain Charles Azagury

Avraham Harpaz

Zvi Yosef Yehudai

Eliezer Dekel

Alexander Krits

Yoelle Smadja Maarek

Roger Lee Haskin

Idan Zach

Guy Laden

Boaz Shmueli

William A Kish

Yariv Aridor

Naama Kraus

Roman Talyansky

Anthony J Zlotek

Chen Chen

Yoelle Maarck-Smadja

When a request is received to perform a data operation requiring an interaction with any one of multiple data replicas stored on one or more data storage devices and managed by a quorum-based data management protocol in which completion of a data update is reported to an initiator of the data update when acceptance of the data update is reported by a majority of the data replicas, the data operation is routed to be performed using one of a predefined minority of the data replicas if the data operation requires less than strong consistency, is a read-only data operation, and meets a predefined criterion of being computationally time-intensive or computationally resource-intensive, or routed to be performed using a predefined majority of the data replicas if the data operation requires strong consistency or requires a data write operation or does not meet the predefined criterion.

Managing data operations in a quorum-based data replication system

A publish-subscribe data messaging system in which wildcard subscriptions are represented in an approximate membership set or filter, such as a Bloom filter, for distribution to brokers together with formatting rules associated with the wildcard subscriptions, where a broker receiving a publication topic of a data publication for distribution to other brokers uses the formatting rules provided by any given broker to create wildcard versions of the publication topic for matching with the wildcard subscriptions that are represented in the approximate membership sets or filters provided by the given brokers, where, if a match exists, the data publication is forwarded to the given broker.

Publish-subscribe system with reduced data storage and transmission requirements

A method for enforcing computer-based file system security, the method comprising generating a content-based file system from files in a physical file system, and enforcing a user access right to any aspect of the content-based file system, where the user access right derives from a user access right to a file in the physical file system.

Content-based file system security

A group communication service maintains synchronization limiting the group to the processing entities that receive a plurality of source message streams from sources outside the group and transmit delivery message streams to destinations that are outside the group. Synchronization of message ordering and other state synchronization directives are communicated from a leader exclusively to other group members. Once having declared themselves to be synchronized and active by a reply protocol message, which is an opaque object and is interpreted by an application layer, the processing entities independently process the source message streams in accordance with the order specified in the directives, without requiring additional sequencing information from another processing entity.

Group communication system achieving efficient total order and state synchronization in a multi-tier environment

A group communication service is adapted for multi-point to multi-point communication. Identical message streams are received by a tier of processing servers from a tier of sources. The processing servers deliver the message streams to a tier of destinations. The group communication service enables the processing servers to deal with newly added message streams and deleted message streams while preserving total ordering.

Synchronization of message stream in a multi-tier messaging system

In an enhanced file system specialized operators are provided, which consolidate contextually sensitive selections of documents from widely scattered

Use of special directories for encoding semantic information in a file system

A XML-aware file system exploits attributes encoded in a XML document. The file system presents a dynamic directory structure to the user, and breaks the conventional tight linkage between sets of files and the physical directory structure, thus allowing different users to see files organized in a different fashion. The dynamic structure is based upon content, which is extracted using an inverted index according to attributes and values defined by the XML structure. In one application, a dynamically changing federated repository is searchable using a system of local and merged master indices, wherein query results are presented as virtual directory paths that are semantically organized.

File system with access and retrieval of XML documents

A method for managing a shared resource that is allocated among nodes in a distributed computing system includes receiving periodic reports from the nodes regarding their respective allocations of the resource. Responsive to the periodic reports, an approximate amount of the resource that is free for further allocation is determined. Typically, the shared resource is a data storage resource, such as a plurality of disks linked to the nodes by a network, which disks are commonly accessible to multiple ones of the nodes.

Maintenance of free resource information in a distributed system

An XML-aware file system exploits attributes encoded in an XML document. The file system presents a dynamic directory structure to the user, and breaks the conventional tight linkage between sets of files and the physical directory structure, thus allowing different users to see files organized in a different fashion. The dynamic structure is based upon content, which is extracted using an inverted index according to attributes and values defined by the XML structure.

A computer system having a shared disk file system running on multiple computers each having their own instance of an operating system and being coupled for parallel data sharing access to files residing on network attached shared disks. A metadata node manages file metadata for parallel read and write actions. Metadata tokens are used for controlled access to the metadata and initial selection and changing of the metadata node.

Parallel file system with method using tokens for locking modes

A computer system having a shared disk file system running on on multiple computers each having their own instance of an operating system and being coupled for parallel data sharing access to files residing on network attached shared disks. Methods are provided for use as a parallel file system in a shared disk environment by use of a scalable directory service for the system with a stable cursor, a segmented allocation map. Dynamic prefetch and cached balance pools for multiple accesses improve the system. Extended file attributes are used for implementation of Access Control Lists in a parallel file system. Improvements to caching and cache performance developments balance pools for multiple accesses. A metadata node manages file metadata for parallel read and write actions. For our system, tokens are used for metadata node selection and identification, and we have enhanced token modes for controlling file size, as well as smart caching of byte range tokens using file access patterns and a byte range lock algorithm using a byte range token interface. Locking techniques reduce the overhead of a token manager which is also used in the file system recovery if a computer participating in the management of shared disks becomes unavailable or failed.

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Zichron Yaakov, Israel

Benjamin Mandler