TR-IIS-05-023    Fulltext

Real-Time Scheduling by Cascading

Ray-I Chang, Ruei-Chuan Chang, Jan-Ming Ho


Real-time scheduling is important for modern computer systems to support increasingly popular multimedia applications. In this paper, we consider a simple video server that receives the commands from clients and sends the video data without error occurred. In the video server, there is one parent thread for dealing with the arrival video tasks. After receiving a new video task from a client, a new child thread is created to determinate the real-time requirements for disk access. Based on the results of traffic smoothing and the sizes of disk blocks, the child thread sends real-time disk requests to the system. Then, a multi-segment cascade scheme is applied to implement the real-time disk scheduling routine on UnixWare operating systems. Both the simulation results and the implementation results are presented for comparisons. The same idea may be extended to handle the real-time scheduling problem with both video server and video proxy [30].