Incremental scheduling of mixed workloads in multimedia information servers

In contrast to pure video servers, advanced multimedia applications such as digital libraries or teleteaching exhibit a mixed workload with massive access to conventional, 'discrete' data such as text documents, images and indexes as well as requests for 'continuous data', like video and audio data. In addition to the service quality guarantees for continuous data requests, quality-conscious applications require that the response time of the discrete data requests stay below some user-tolerance threshold. In this paper, we study the impact of different disk scheduling policies on the service quality for both continuous and discrete data. We provide a framework for describing various policies in terms of few parameters, and we develop a novel policy that is experimentally shown to outperform all other policies