Deadline-modification-SCAN with maximum-scannable-groups for multimedia real-time disk scheduling

Real-time disk scheduling is important to multimedia systems support for digital audio and video. In these years, various approaches are presented to use the seek-optimizing scheme to improve the disk throughput of a real-time guaranteed schedule. However, as these conventional approaches apply SCAN only to the requests with the same deadline or within the same constant-sized group, their improvements are limited. In this paper, we introduce the DM-SCAN (deadline-modification-SCAN) algorithm with an idea of MSG (maximum-scannable-group). The proposed DM-SCAN method can apply SCAN to MSG iteratively by modifying request deadlines. We have implemented the DM-SCAN algorithm on UnixWare 2.01. Experiments show that DM-SCAN is significantly better than that of the best-known SCAN-EDF method in both the obtained disk throughput and the number of supported disk requests.