In contrast to pure video servers, advanced multimedia applications such as
digital libraries or teleteaching exhibit a mixed workload with massive ac
cess to conventional, "discrete" data such as text documents, images and in
dexes 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 disc
rete data requests stay below some user-tolerance threshold. In this paper,
we study the impact of different disk scheduling policies on the service q
uality for both continuous and discrete data. We provide a framework for de
scribing various policies in terms of few parameters, and we develop a nove
l policy that is experimentally shown to outperform all other policies.