Tracking Real-Time Systems Requirements
Aloysius K. Mok · 2000
One of the hard problems in maintaining real-time systems requirements is to keep track of the impact of resource usage on the applications. Often times, it is not sufficient to keep track of upper bounds since some requirements such as jitter are also sensitive tothe lower bounds and the resource scheduling algorithm employed. In the case of non-preemptive scheduling, real-time requirements can be missed when resource utilization is decreased as in a CPU upgrade, eventhough there are no jitter constraints. In this paper, we define the notion of robustness for real-time performance requirments and discuss the tracking of sensitivity of real-time application requirements with respect to resource usage by formal method. Weshall drawasanexample the performance requirements of the avionics software of the Boeing 777 aircraft. 1.