RCPCP: A Ceiling-based Protocol for Multiple-disk Environments

Processes running in a multiple-disk environment may share non-preemptible resources on the processor and, at the same time, request services from disk subsystems. In this paper, we propose a methodology which is efficient and easy to implement for scheduling processes in multiple-disk environments. In other words, our methodology addresses the scheduling of real-time processes which may stop to wait for disk I/O without releasing any locked semaphores. Our proposed methodology is a variation of the well-known priority ceiling protocol to schedule processes running in multiple-disk environments. The capability of the proposed methodology is verified by a series of simulation experiments under different workloads of CPU-bound and I/O-bound processes in multiple-disk environments, for which we have some encouraging experimental results.