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 T₀ and T_t where T₀ 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 T₀. In this context, we derive necessary and sufficient conditions applicable to the schedule obtained for T₀ at time 0 such that, any future task set T_t can be scheduled provided the task set T₀∪T_t is feasible using m processors