Abstract: A method providing integrity analysis of content data streams within an information distribution system. On-demand content is divided into a plurality of content portions to be severally distributed among disk drives of an array of disk drives. A data structure is used for dividing the content into the plurality of content portions. Method is used to check integrity of content prior to provisioning thereof.

Abstract: A method and apparatus for migrating one or more users from a source server module to a destination server module in a manner avoiding information discontinuities or otherwise degrading the users' viewing experience.

Abstract: A method for streaming content striped in RAID 5 format from an array of disk drives to subscribers to minimize disruptive service from a disk drive failure. The method includes accessing content data on an extent-by-extent basis from a plurality of disk drives in an array and streams the content data to the subscribers on an extent-by-extent basis, sequentially, from the plurality of disk drives. Upon detection of an actual disk drive failure the method transitions to a stream regeneration mode of operation, which includes reading the content data substantially simultaneously from all extents in a parity group and regenerating a failed portion of the content data from a failed extent in the parity group corresponding to the failed disk drive. The content data in the parity group is streamed to the subscribers, extent-by-extent, immediately following the regenerating of the content data from the failed extent in the parity group.

Abstract: A queuing architecture and method for scheduling disk drive access requests in a video server. The queuing architecture employs at least two access request queues for each disk drive within a disk drive array, and a queue selector for selecting the first and second queues. The first queue is for disk access requests by steady-state users requesting new data streams who are currently viewing a program from the video server. The second queue is for all other types of disk access requests, including requests by new users, requests for loading content, disk maintenance, meta-data synchronizing, and the like. Steady-state disk access requests are serviced in order of ascending time deadlines. The queue selector gives highest priority to requests in the first queue, and requests from the second queue are serviced only upon a guarantee that all of the steady-state requests in the first queue will meet their time deadlines in the worst case access times for the disk drives.

Abstract: A queuing architecture and method for scheduling disk drive access requests in a video server. The queuing architecture employs a controlled admission policy that determines how a new user is assigned to a specific disk drive in a disk drive array.

Abstract: A method of data management for efficiently storing and retrieving data in response to user access requests.

Abstract: A method of defining extent for storing a plurality data streams having different bit rates. The method calculates the size of the extent for a given data stream then periodically inserts at least one null packet into the extents to enable any bit rate to be able to be stored using a fixed extent size for the stream.

Abstract: A storage server for efficiently retrieving data from a plurality of disks in response to user access requests. The server comprises a plurality of processors coupled to disjoint subsets of disks, and a custom non-blocking packet switch for routing data from the processors to users. By tightly coupling the processors to disks and employing an application-specific switch, congestion and disk scheduling bottlenecks are minimized. By making efficient use of bandwidth, the architecture is also capable of receiving real-time data streams from a remote source and distributing these data streams to requesting users. The architecture is particularly well suited to video-on-demand systems in which a video server stores a library of movies and users submit requests to view particular movies.

Abstract: A method and apparatus for managing both link and disk bandwidth utilization within the context of a multiple subscriber or user information distribution system by selectively providing variable bitrate and constant low bitrate information streams to one or more subscribers.

Abstract: A method and apparatus for managing both link and disk bandwidth utilization within the context of a multiple subscriber or user information distribution system by selectively providing variable bitrate and constant low bitrate information streams to one or more subscribers.

Abstract: A storage server for efficiently retrieving data from a plurality of disks in response to user access requests. The server comprises a plurality of processors coupled to disjoint subsets of disks, and a custom non-blocking packet switch for routing data from the processors to users. By tightly coupling the processors to disks and employing an application-specific switch, congestion and disk scheduling bottlenecks are minimized. By making efficient use of bandwidth, the architecture is also capable of receiving real-time data streams from a remote source and distributing these data streams to requesting users. The architecture is particularly well suited to video-on-demand systems in which a video server stores a library of movies and users submit requests to view particular movies.

Abstract: A method of defining extent for storing a plurality data streams having different bit rates. The method calculates the size of the extent for a given data stream then periodically inserts at least one null packet into the extents to enable any bit rate to be able to be stored using a fixed extent size for the stream.

Abstract: A queuing architecture and method for scheduling disk drive access requests in a video server. The queuing architecture employs at least two access request queues for each disk drive within a disk drive array. The first queue is for disk access requests by steady-state users who are currently viewing a program from the video server. The second queue is for all other types of access requests including disk access requests by users who wish to begin viewing a program, content loading, meta-data syncing and the like. The method maintains time deadlines for steady-state disk access requests and services these requests in order of ascending deadlines. Requests from the second queue are serviced only if it can be guaranteed that all of the steady-state requests in the first queue will meet their time deadlines in the worst case access time for the disk drive. By taking advantage of the variability of disk seek and transfer times, the method improves the effective disk bandwidth of the video server.

Abstract: A method of data management for efficiently storing and retrieving data in response to user access requests. The architecture comprises a plurality of disk drives over which data is distributed, and a plurality of processors, each of which is assigned to a subset of the disk drives in a modular fashion. The server architecture employs dynamic data management methods and load-balancing methods to assign user requests to processors. The modular server architecture, in combination with the dynamic data management and load balancing methods, provides both good performance (i.e., low expected-case access times and high disk bandwidth), and fault-tolerance. The architecture is particularly well suited to video-on-demand systems in which a video server stores a library of movies and users submit requests to view particular programs.