A greedy-but-safe dynamic scheduling strategy for an interactive video-on-demand server

We study a dynamic approach to the problem of scheduling real time requests in a video on demand server. Most of the previous VOD scheduling approaches use limited run time information, and thus cannot exploit the potential capacity fully. Our approach improves throughput by making use of run time information to relax admission control, and to reduce admission to start delay by providing earliest initial service. We establish conditions for greedy admission, dynamic control of the sequence and sizes of disk accesses, and fast initial service. We conduct thorough simulations over a wide range of buffer capacities, load settings, and over varying playout rates to demonstrate the significant improvements in throughput and admission re start delay of our approach relative to a typical static approach which does not use run time information.