In the recent decade, the computer system have greatly improved and the type of systems have been increased. Accordingly, there is lots of need for real-time system to guarantee deadline and quality of service.
In the past, there was many researches about hard real-time algorithms for single resource and soft real-time systems for multiple resources. Because the hard real-time scheduling problem in the environment that has multiple resources is NP-complete problem, it is hard to schedule these resources effectively while guaranteeing the deadline.
However, disk has special abilities that help schedule with a processor in a hard real-time system. It is possible to prefetch from a disk and to delaying writing on it. In this paper, we intoruduce the method of a hard real-time co-scheduling of a disk and processor by using prefetching and delayed writing by one period. And we also show the mathematical verification and limited memory usage of this method.
We implemented this method in a Linux system and evaluated. The results show that it can be applied in a real world system and it works without a deadline miss.
