Starlight Networks, Inc.

Randall B Baird

Fouad A Tobagi

Joseph M Gang, Jr

Joseph W Pang

Martin J McFadden

Charles J Bedard

James E Long

Joseph Mark Gang, Jr

Joseph W M Pang

David A Edwards

A method for increasing the storage capacity of a video server which utilizes an array of disks is disclosed. The server is operated so that the continuity of a plurality of bit streams is maintained. The inventive method has advantageous characteristics with respect to storage capacity, streaming capacity, start-up latency of new streams, amount of required buffer capacity, scalability, reliability and multiple bit rates.

Method for operating an array of video storage units

A method is disclosed for interfacing a video storage system, such as a disk array, and a video stream application executing on a computer network or stand-alone system. The interface provides a method for storing video stream data by allocating storage space in units of stripes and for accessing the data in units of fixed length segments, wherein each stripe includes one fixed length segment from each disk of the array. The interface also queues submitted I/O transaction requests so that I/O transactions requested on a current I/O cycle i are not performed until the next I/O cycle i+1. The I/O transactions thus queued are performed in an order which permits a maximum number of I/O transactions to be performed each I/O cycle, regardless of the order in which they were submitted. In addition, the interface also queues the submitted I/O transaction requests so that the completion of an I/O transaction on a current I/O cycle i is not returned until the next I/O cycle i+1. The completions of the I/O transactions thus queued are returned in the order they were submitted regardless of the order in which they were performed. Furthermore, the interface provides a state machine which controls the amount of data accessed each I/O cycle for a corresponding stream. The state machine permits no more than a particular allotted amount of data to be accessed each I/O cycle, wherein the allotted amount of data is selected according to the bandwidth requirement of the corresponding stream.

Method for accessing one or more streams in a video storage system using

A method for operating a disk storage system, comprising a disk and forming part of a communications network, simultaneously maintains the continuity of a plurality of data streams. Typically, each stream transfers video data to or from the disk storage system. Illustratively, each of the data streams is produced in the network at a rate of W.sub.base bits/sec and consumed by the disk storage system or produced by said disk storage system and consumed in the network at a rate of W.sub.base bits/sec. One I/O transaction is performed for each stream in each of a plurality of I/O cycles of duration S/W.sub.base, wherein in each I/O transaction a segment of S bits is retrieved from or stored in the disk. The number of streams whose continuity can be maintained in this manner is limited by the number of I/O's which can be performed in a cycle of duration S/W.sub.base. More generally, when a stream has a bit rate (A/B)W.sub.base bits/sec where A and B are integers chosen independently for each stream, then for this-stream A I/O transactions are performed in B cycles of duration S/W.sub.base. If the number of disks is N.sub.d, N.sub.d, .ltoreq.1, then the I/O cycles have a duration N.sub.d S/W.sub.base and then A I/O transactions are performed in each disk for each stream in B I/O cycles.

Method for scheduling I/O transactions for a data storage system to

A method for operating a disk storage system, comprising a disk and forming part of a communications network, simultaneously maintains the continuity of a plurality of data streams. Typically, each stream transfers video data to or from the disk storage system. Illustratively, each of the data streams is produced in the network at a rate of W.sub.base bits/sec and consumed by the disk storage system or produced by said disk storage system and consumed in the network at a rate of W.sub.base bits/sec. One I/O transaction is performed for each stream in each of a plurality of I/O cycles of duration S/W.sub.base, wherein in each I/O transaction a segment of S bits is retrieved from or stored in the disk. The number of streams whose continuity can be maintained in this manner is limited by the number of I/O's which can be performed in a cycle of duration S/W.sub.base. More generally, when a stream has a bit rate (A/B)W.sub.base bits/sec where A and B are integers chosen independently for each stream, then for this stream A I/O transactions are performed in B cycles of duration S/W.sub.base. If the number of disks is N.sub.d,N.sub.d .gtoreq.1, then the I/O cycles have a duration N.sub.d S/W.sub.base and then A I/O transactions are performed in each disk for each stream in B I/O cycles.

Method for scheduling I/O transactions in a data storage system to

Method for operating a disk storage system which stores video data so as

Method for scheduling I/O transactions for video data storage unit to

Method for performing I/O's in a storage system to maintain the

A local area network for supporting video applications comprises a transmission medium, one or more data file servers connected to the transmission medium for supporting data applications in the local area network, a dedicated video server for supporting video applications in the local area network and one or more clients connected to the local area network. The server includes software for managing multiple simultaneous video streams transmitted across the LAN. The client includes software for accessing the dedicated video server across the LAN to transmit video to the server or receive video from the server.

Video application server

A station is provided which is connected to a network segment via a shared transmission medium. The station includes one or more protocol stacks for processing each type of data packet which the station may transmit to or receive from the shared transmission medium. A queue is associated with each protocol for storing corresponding data packets. The station is also provided with a media access controller, which is unable to differentiate among the different types of data packets. The media access controller is provided for enabling data packets of the different types stored in the queues to access the transmission medium with arbitrary priority. A throttler is also provided for controlling the submission of data packets from the queues to the media access controller, depending on the type of the data packets, to provide an appropriate amount of bandwidth in, and to limit the access delay of, a particular type of data packets in the shared transmission medium.

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San Jose, CA, United States of America

Randall B Baird