Abstract: A Distributed Video System provides a scalable and interactive video-on-demand service with VCR operations over a communication network includes a video server and video clients, each of which includes a memory buffer, called a client buffer. The System provides a method of managing video frames of client buffers in a cooperative way with video frames held in the video server allows the video frames of the client buffers to be shared among the video clients. Requests for a video are primarily served by the video clients that have the requested video frames in their client buffers and only requests that the video clients are unable to attend to will be provided by the video server.

Abstract: This invention treats of a two-level cache management method for continuous media files of a proxy server. In the first level, the method reserves collapsed buffers in the cache for every active client attended by the proxy server. To save bandwidth and memory space collapsed buffers can be concatenated and overlapped when content belongs to the same continuous media file. The proxy manages collectively the collapsed buffers of each client, which cooperate by making its content available to the whole system, reducing traffic over the communication network and on the media-on-demand server. In the second level, the method allows proxy servers to cooperate between themselves, by concatenating collapsed buffers when necessary, increasing the amount of available shared media in the cache, saving bandwidth both on the media-on-demand server and on the communication network backbone.

Abstract: The present invention refers to a global clock system for clusters or networks of computers implemented entirely in hardware. The system uses a specifically designed hierarchical network to distribute clock pulses that are used to increment time counters in the cluster' nodes. In addition, this network enables any node of the cluster to send a reset signal to the other nodes so that all local time counters are initialized simultaneously and remain automatically synchronized afterwards. In this way, each processor in the cluster is able to obtain the value of the global clock whenever accessing its own local time counter. The reset signal is the only function that is implemented in software.

Abstract: A method is disclosed to improve the scalability of Video on Demand Systems with VCR functions using the client buffers in a cooperative way.