A time-scale dependent disk scheduling scheme for multimedia-on-demand servers

We present a producer-consumer model of multimedia-on-demand servers. The producer retrieves media data from a disk and places it into a set of buffers while the consumer sends out the data in the buffers to the users. We develop for the producer a time-scale dependent buffer-inventory-based dynamic scheduling scheme named σ-BIDS which guarantees to meet the continuity requirement and no-loss of data for each media stream. The scheme introduces a time-scale dependent peak consumption rate and a virtual cycle time to smooth out the impact of bursty data of variable-bit-rate streams, thus improving the maximum admissible load of requests. A straightforward admission control mechanism with quality-of-service guarantees is then established based on two simple conditions respectively on load and buffer size. Our scheduling scheme is very easy to implement, and experiments carried out with an actual disk system and real video stream data verify the effectiveness of the scheme