Abstract: A system, method and apparatus for Video-on-demand (VOD) satisfying the desire of `surfers`. The process entails a server operating in a standard Near-Video-on-demand (NVOD) mode, whereby it repeatedly transmits multiple copies of each program on separate channels. Each copy is delayed by a staggered time interval. The server also repeatedly transmits a beginning portion of each NVOD program of a duration up to the staggered time interval. The invention provides a way to fulfill a VOD user requests asynchronous with the start of a NVOD transmission but which still makes primary use of the NVOD transmission for that requestor. The invention further advantageously provides fixed asset utilization in a predictable manner.

Abstract: A system and methods for implementing a video encoder which for each picture guarantees that the number of bits produced will not exceed a limit. In a preferred embodiment, the system includes two cooperating components or subsystems that together with other components of a video encoder operate to encode the input video, detect when the limit on the number of bits produced so far is close to exceeding the limit on the number of bits that may be produced and reduce the bit rate when such a condition is detected. One aspect of the current invention embodies a macroblock (MB) bit stream generator that can operate in a "low bit rate mode" Another aspect embodies a subsystem for detecting when the number of bits in the picture is close to exceeding the limit.

Abstract: A system and method for recovering from failures in the disk access path of a clustered computing system. Each node of the clustered computing system is provided with proxy software for handling physical disk access requests from applications executing on the node and for directing the disk access requests to an appropriate server to which the disk is physically attached. The proxy software on each node maintains state information for all pending requests originating from that node. In response to detection of a failure along the disk access path, the proxy software on all of the nodes directs all further requests for disk access to a secondary node physically attached to the same disk.

Abstract: An electrical apparatus (100) line actuator (102), such as a voltage regulator or circuit breaker, has resident therein a personality module, electronically reconfigurable memory device (126) which stores actuator operational information, such as specifications (132), historical and maintenance information. An apparatus controller (106) communicates with the personality module (126) and can change the operational information stored therein. If either or both of the controller (106) and actuator (102) is replaced at a site, the controller (106) of the replacement apparatus configuration (100) can read the operational information stored in the personality module (126) and adapt its operational interaction with the actuator (102) in conformance with the information.

Abstract: In a fault-tolerant distributed file system, the server state needs to be reconstructed after the server restarts or when its function is taken over by another node. A crucial part of the server state is determining whether or not in-flight, directory-operations initiated by the clients have been completed. Described is a check-before-request scheme that solves this problem. A global lock is obtained on the directory or directories first. A check is made on the directories to see if the operation would succeed, and if so a request is made to the server for the operation. If the server were to fail during the execution of the operation, completion of the operation prior to failure can be determined by merely re-examining the directory contents.

Abstract: A system and methods for implementing an encoder suitable for use with the motion picture compression. The system includes a motion estimation apparatus which performs temporally interpolative motion estimation. The temporally interpolative motion estimation is performed by first performing unidirectional motion estimation between the current picture and one or more other pictures. The results of the unidirectional motion estimation alone, and not any picture data, are used to perform temporally interpolative motion estimation.

Abstract: A voltage regulator controller having integral expansion ports. The expansion ports are provided by way of an I/O expansion chassis which is electrically coupled to the controller's microprocessor.

Abstract: A system and method for receiving a video sequence with a given aspect ratio and displaying that sequence on a device with a different aspect ratio in letterbox form by performing letterbox type conversion immediately before display. In letterbox form, the viewer sees the entire active region of the picture but the whole screen is not used. In one embodiment a video sequence with a given aspect ratio can be displayed on a device with a different aspect ratio in letterbox or pan-scan form, at the users discretion, by performing, respectively, letterbox or pan-scan conversion immediately before display. Thus, the user can decide to use the entire screen or to see the entire picture.

Abstract: A system and method for repeat field detection for use in rate conversion and video encoding of the type contemplated by the MPEG standards. Before encoding a frame, first field in the current frame is compared to the previously occurring field of the same parity. Next, a single number (the inter-field parameter) is generated, which is a measure of the difference between the two fields. If the inter-field parameter is below a threshold a signal is generated to indicate that the current field is a repeat of the previous field of the same parity. Otherwise, the signal is generated to indicate that the field is not a repeat of the previous field of the same parity (i.e. the field likely contains at least one small area of motion).

Abstract: A system and method for allowing a distributed, coherent network filesystem to have virtual filesystem instantiations existent on any number of client nodes as well as on the server node that maintains the physical instantiation. On the server node only one image of the filesystem is visible even though two instantiations (physical and virtual) have been realized on that node. The rendering the physical instantation invisible and inaccessible is accomplished by performing a "takeover" of the physical filesystems data structures by the virtual filesystems mounting subroutines.

Abstract: An electrical apparatus (100) line actuator (102), such as a voltage regulator or circuit breaker, has resident therein a personality module, electronically reconfigurable memory device (126) which stores actuator operational information, such as specifications (132), historical and maintenance information. An apparatus controller (106) communicates with the personality module (126) and can change the operational information stored therein. If either or both of the controller (106) and actuator (102) is replaced at a site, the controller (106) of the replacement apparatus configuration (100) can read the operational information stored in the personality module (126) and adapt its operational interaction with the actuator (102) in conformance with the information.

Abstract: A range of key values is partitioned into a plurality of key subranges equal in number to the number of record storage areas available for the sort. One of the key subranges is then assigned to each of the record storage areas and records to be sorted are transferred to the record storage areas in accordance with a sort key value within each record and the key subrange assigned to each of the record storage areas. Whenever a record is transferred to a filled record storage area, a record from the filled record storage area is transferred to an output string, namely the record that has the lowest key value that is not lower than the last record added to the output string of the filled record storage area.

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 non-disruptive recovery from a file server failure. State information for a file system managed by a server is maintained among a plurality of client nodes of a distributed system. When a failure of the server is detected, all ongoing requests to server are suspended. Then, the state information in each client node is transferred to an identified back-up server. Based on the state information, the file server state prior to the failure is reconstructed. After the reconstructing the file system, the suspended requests are restarted on the back-up server.

Abstract: A Video-On-Demand (VOD) scheduler maintains a queue of pending performance for at least one movie and determines a maximum wait tolerance time for a longest waiting one of the pending performance requests. When stream capacities become available, rather than scheduling the movie immediately the scheduler delays performance of the video until just prior to expiration of the maximum wait tolerance time of the longest waiting one of the pending performance requests. In the interim, additional streams can join queue. When the performance occurs all performance requests on the queue are served from the a single stream provided from the assigned stream capacity.

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 method of distributing a set of data among a plurality of disks, which provides for load balancing in the event of a disk failure. In accordance with the method the total number of the disks in an array are divided into a number of clusters. The blocks of data are then stored in each cluster such that each cluster contains a complete set of the data and such that data block placement in each cluster is a unique permutation of the data block placement in the other clusters. In the event of a disk failure, data block accesses to the failed disk are redirected to a disk in the other cluster having a copy of the data block and further access to the disks that remain operational are rebalanced.

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 placement system and method wherein the placement of programs such as movies, audio programs, audio-visual programs and similar types of data, is determined as a function of the bandwidth-space ratio (BSR) of each disk in the system. The BSR of a disk is defined as the bandwidth of the disk divided by the space. The BSR of the programs on the disk is the total expected demand for the programs divided by the space required to store the programs. In a preferred embodiment, a Video Placement Manager (a software task operating under a server's main control program) places the programs on the disks so as to best match the BSR of movies stored on the disk and the BSR of the disk, thus minimizing the waste of both disk bandwidth and disk space.

Abstract: A system for placing a visible "watermark" on a digital image is disclosed, wherein an image of the watermark is combined with the digital image. The pixels of the watermark image are examined, and for each pixel whose value is not a specified "transparent" value, the corresponding pixel of the original image is modified by changing its brightness but its chromaticities. This results in a visible mark which allows the contents of the image to be viewed clearly, but which discourages unauthorized use of the image.