Method for scheduling I/O transactions for video data storage unit to maintain continuity of number of video streams which is limited by number of I/O transactions

Abstract

Abstract 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 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 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 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 base . More generally, when a stream has a bit rate (A/B)W 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 base . If the number of disks is N d ,N d ≧1, then the I/O cycles have a duration N d S/W base and then A I/O transactions are performed in each disk for each stream in B I/O cycles.

Inventors

• 👤 Fouad A. Tobagi
• 👤 Joseph M. Gang, Jr.
• 👤 Randall B. Baird
• 👤 Joseph W. M. Pang
• 👤 Martin J. McFadden

Bibliographic Details