On-line scheduling of hard real-time tasks on multiprocessors

We consider the problem of on-line scheduling of a set of hard real-time tasks in an environment where future task parameters are not known a-priori. First, we derive necessary and sufficient conditions to determine whether a given set of tasks with known parameters is feasible using a set of m processors. Next, we consider two sets of tasks T-0 and T-t where T-0 is the set of tasks that need to be scheduled at time 0 such that any future task set T-t, t > 0 can be scheduled with or without disturbing the schedule for T-0. In this context, we derive necessary and sufficient conditions applicable to the schedule obtained for T-0 at time 0 such that any future task set T-t can be scheduled provided the task set T-0 boolean OR T-t is feasible using m processors.