Abstract
This paper considers the problem of hard real-time fixed priority scheduling of sporadic graph tasks on a uniprocessor. We study feasibility conditions based on the computation of the worst case response times of the graph tasks. A sporadic graph task associated to an application is characterized by a set of subtasks under precedence constraints. We investigate the late deadline constraint. We extend already published papers established in the preemptive case to the non-preemptive case and to the hybrid case of an application composed of preemptive and non preemptive subtasks.