Non-preemptive real-time scheduling of multimedia tasks

Motivated by the special characteristics of multimedia tasks, we consider non-preemptive scheduling of tasks where there exists no (or very limited) information concerning the tasks before they are released. We present impossibility results and analyze algorithms for non-preemptive scheduling in single processor and multiprocessor systems. In particular, one set of our results considers the competitive ratio of the scheduling algorithm when the length of the tasks is not greater than C/sub max/ (and not smaller than C/sub min/). We show that the performance of a scheduling algorithm is improved dramatically when the release time of the tasks is O(C/sub max/) prior to their deadline; achieving a competitive ratio that is close to one.