Abstract: A conversation monitoring system includes a communication network, two or more parties coupled to the communication network, each party having a computer application, and a conversation monitor located at at least one of the parties and adapted to provide an interaction history of long running conversations accessible to each computer application.

Abstract: A method and system for improving load balancing in a file server is disclosed. The method includes determining the existence of an overload condition on a storage device, the storage device having a plurality of retrieval streams accessing at least one file thereon; selecting a first retrieval stream reading a file; replicating a portion of said file being read by said first retrieval stream onto a second storage device; and reading the replicated portion of said file on said second storage device with a retrieval stream capable of accessing the replicated portion of said file. The method and system enables the dynamic replication of data objects to respond to fluctuating user demand. The method and system is particularly useful in file servers such as multimedia servers delivering continuously in real time large multimedia files such as movies.

Abstract: A service contract system for providing a service includes a communication network, a plurality of parties coupled to the communication network and a service contract specifying unambiguous rules of interaction for the parties during transactions for the service. A method for managing service transactions between a plurality of parties coupled to a communication network, includes the steps ofjointly developing a service contract having unambiguous rules of interaction between the plurality of parties regarding a service, registering the service contract in each of the plurality of parties and generating, from the service contract, enforcer modules consistent with the rules of interaction for managing transactions of the service.

Abstract: Fileserver buffers are managed so as to improve the hit ratio for read accesses to the fileserver by clients by grouping related files into filesets, collecting fileserver access operation (i.e., read and write) statistics for each of the filesets, classifying the filesets into a plurality of fileset categories having similar collected access operation statistics and then implementing different fileserver buffer management policies for the blocks (or pages) from each of the different fileset categories. The buffer management policy applied to each of these categories is designed to create a generally higher preference for retaining blocks (or pages) of files in the fileserver buffers having a generally higher read to write ratio.

Abstract: A system and method for use in a distributed video-on-demand system of a type wherein at least one node provides blocks of video data to clients and wherein at least some of the blocks of video data are replicated on multiple nodes. Observed response characteristics for other nodes are recorded at least a given one of the nodes which serves a client requesting a replicated block. The given one of the nodes also records response characteristics reported to it by the other nodes. The node from which to fetch the replicated data block is selected based on which nodes include a copy of the replicated data block and based on at least one of the observed response characteristics and the reported response characteristics.

Abstract: The functionality of Web clients (e.g. browser) is enhanced using a WebFilter Manager (WFM) that allows i) easy integration of individual WebFilters operating on ingoing or outgoing messages between the browser and web servers, ii) arbitrary and dynamic ordering of WebFilters operating on a message stream, iii) splitting, combining, modifying and processing of message streams by WebFilters. The same methodology can also be applied in any client server environment for extending the functionality of the client or server.

Abstract: A form of authentication is provided wherein a trusted third party signs a certificate to identify the author of a program and to secure its integrity. The program code is encapsulated or otherwise associated with the certificate and an access control list (ACL). The access control list describes the permissions and resources required by the code. An enforcement mechanism which allocates system permissions and resources in accordance with the ACL. In a preferred embodiment, a code production system communicates with a certification agency, which is a trusted third party. The certification agency issues a certificate for the code and a certificate for the access list of that code. Once the certificate is issued it is not possible for any party to modify the code or access list without invalidating the certificate. The code and its ACL, along with their certificates are stored on a server.

Abstract: A video server is provided with buffer manager which balances the loads on the various "movie storage" elements of a video server by preferentially buffering streams on highly loaded storage elements. The allocation of buffer takes place only when the storage element load increases due to the arrival of a new request or when buffer becomes available due to the pausing or stopping of an old request.

Abstract: A method and system for improving load balancing in a file server is disclosed. The method includes determining the existence of an overload condition on a storage device, the storage device having a plurality of retrieval streams accessing at least one file thereon; selecting a first retrieval stream reading a file; replicating a portion of said file being read by said first retrieval stream onto a second storage device; and reading the replicated portion of said file on said second storage device with a retrieval stream capable of accessing the replicated portion of said file. The method and system enables the dynamic replication of data objects to respond to fluctuating user demand. The method and system is particularly useful in file servers such as multimedia servers delivering continuously in real time large multimedia files such as movies.

Abstract: A system and method for caching sequential data streams in a cache storage device. For each information stream, a determination is made as to whether its data blocks should discarded from cache as they are read by a consuming process. Responsive to a determination that the data blocks of a stream should be discarded from the cache are read by the consuming process, the data blocks associated with that stream are cached in accordance with an interval caching algorithm. Alternatively, responsive to a determination that the data blocks of a stream should not be discarded from the cache storage device as they are read by the consuming process, the data blocks of that stream are cached in accordance with a segment caching algorithm.

Abstract: A system and method are provided for determining load capacity of a system. Physical components of the system and their interconnection are identified. The physical components are converted into logical components such that at least one logical component is created by grouping a plurality of the physical components and such that a load on the logical component will result in an approximately fixed proportional load on the plurality of physical components. Links between the logical components and a proportion of the load placed on each link between a source and destination pair are determined. A model of the logical components and interconnection of the logical components in is then stored in an electronically accessible data structure formed in a memory. A system and method for determining a path for routing data between a source and a destination pair in a system are also provided.

Abstract: A system and method for scheduling the number of channels in video-on-demand servers so as to deal with time varying load. The scheduling process is hierarchical. A higher level scheduler controls the rate of channel consumption based on anticipated load, and a lower level scheduler selects the waiting client requests to be served when a channel is allocated by the higher level scheduler.

Abstract: A method for reducing the disk bandwidth capacity required by a multimedia server by selectively retaining blocks that have already been read in by one stream for re-use by another. Due to stream-dependent block buffering, the storage requirement is less than that for whole-movie buffering and because the policy is dynamic, it also adapts rapidly to changing access patterns.

Abstract: A system and method for controlling transmission of a data stream by a server to a plurality of clients in a multicast group. In a first embodiment, one of the clients in a multicast group is designated as a leader. When a service request for transmission of a portion of the data stream is received by the server from any of the clients, the server determines if the service request was from the leader. Responsive to determining that the service request was from the leader, the server broadcasts the portion of the data stream to the clients in the multicast group. Otherwise the broadcasting is deferred. In another embodiment responsive to receipt of the service request for playout of a portion of a video (e.g. a block) from any of the clients in a multicast group, the server determines if a predetermined broadcast criteria has been satisfied. If so the server broadcasts the requested portion to all of the clients in the multicast group.

Abstract: A video server is provided with buffer manager which balances the loads on the various "movie storage" elements of a video server by preferentially buffering streams on highly loaded storage elements. The allocation of buffer takes place only when the storage element load increases due to the arrival of a new request or when buffer becomes available due to the pausing or stopping of an old request.

Abstract: In a digital storage disk array system in which parity blocks are created and stored in order to be able to recover lost data blocks in the event of failure of a disk, high-activity parity groups are created for data blocks having high write activity and low-activity parity groups are created for data blocks not having high write activity. High-activity parity blocks formed from the high-activity data blocks are then stored in a buffer memory of a controller rather than on the disks in order to reduce the number of disk accesses during updating.

Abstract: An integrated scheduling approach that provides VCR control functions to clients without always requiring a separate video stream for all clients. When a client invokes a resume, following a pause, the system uses a hierarchy of methods to handle the request. If an ongoing video stream is available such that the point at which the client is paused will be reached by that stream within a tolerable delay, the client is assigned to the ongoing stream. If no such stream is available, and the client request can not be served from a buffer, the system assigns the client to a reserve stream taken from a pool of reserved server capacity. If no reserved server capacity is available, the client is given priority for assignment to the next stream to become available.