We have designed and implemented a controllable software architecture for a Video-on-Demand (VOD) server. With the proposed software architecture, many system design issues can be investigated. For example, we studied several disk striping schemes in the storage subsystem and examined the impact of the disk striping schemes on the utilization of system resources. In the processing component, we observed that additional concurrent video streams can be supported by using efficient memory interleaving. Buffering with a large memory space in the processing subsystem is a common technique to alleviate the latency variance of accessing different system components. By employing user-level control and scheduling, the variance can be decreased thereby reducing the resulting buffer space needed for each video stream. In the network subsystem, we adopted a server-driven approach for investigating MPEG-2 video delivery over Asynchronous Transfer Mode (ATM) networks. The VOD server controls the pace of video transmission and reduces the complexity of the client. Since the client has limited buffer space (due to cost considerations), we have reduced the buffer requirement by regulating the transmission based on timing information embedded in the MPEG-2 streams. Our research and experimental results are based on a VOD server which is currently under construction. The prototype server is based on an SGI shared-memory multiprocessor with a mass storage system consisting of RAID-3 disk arrays. Using 30 RAID-3 disk arrays, preliminary experimental results show that the prototype server can potentially support more than 360 high-quality video streams with careful design and coordination of the different system components.
|Original language||English (US)|
|Number of pages||32|
|State||Published - Dec 1 1998|