A2.79 competitive on-line algorithm for two processor real-time systems with uniform value density

We consider the problem of competitive on-line scheduling in two processor real-time systems. In our model all tasks have common value density. Each task has a release time, an execution time and a deadline, The scheduler is given no information about a task until it is released. And the value will be achieved if and only if the task is completed by its deadline. Moreover, we suppose that migration is not allowed. The goal of the scheduler is to obtain as much value as possible. In this paper we show that the competitive multiplier of Safe-Risky-fixed Algorithm m [4] is really 3 and presents a modified algorithm (Safe-Risky-unfixed Algorithm) that achieves a competitive multiplier of 2.79. © 1997, Appl. Math. J. Chinese Univ. Ser. B. All rights reserved.