A Novel Deadline Driven Disk Scheduling Algorithm for Multi-Priority Multimedia Objects

In this paper we introduce a new deadline driven disk scheduling algorithm designed for multimedia servers. The proposed algorithm supports real time requests with multiple priorities, e.g., those for di erent object classes in digital library applications. The proposed algorithm enhances utilization of disk bandwidth by (a) maintaining one queue for all requests, and (b) optimizing the seek time. Prior schemes, collectively termed \Multi-queue schemes", maintain a separate queue for each priority group and optimize the performance of the high priority requests only. When compared with our proposed scheme, our technique provides approximately two order of magnitude improvement in meeting the deadline of low priority requests. In addition, this algorithm provides both a better disk utilization and a better average response time. Under certain conditions, our algorithm violates the deadline of a few high priority requests (less than 5 out of a million requests).