Real-time scheduler for Windows NT

Most operating system schedulers are not flexible enough to support dynamic scheduling policies like earliest deadline first and least slack algorithms. Some of these algorithms are widely used in real-time applications. This paper looks into the issues involved in developing a real-time scheduler for a general purpose operating system. We describe the implementation of a user-level threads package which has the flexibility of supporting any scheduling policy. By sharing stack space between kernel threads, we attempt to address the inherent problem of starvation and non-preemption for a user-level scheduler. The results of comparative evaluation show that a user-level scheduler performs better than the operating system scheduler. We also look into feasibility of using Windows NT for real-time applications requiring I/O subsystem services.