Schedulability Analysis for Real-Time Processes with Age Constraints

Real-time systems not only require the semantical correctness of their operations but also the availability of the computational results within some predefined time intervals. Typical applications are composed of processes which are responsible to execute time-bound computations. Depending on the application specific context processes have to complete due to time constraints. Most frequently are periodic time constraints for which various schedulability tests have been developed. Recently age constraints have shown to be adequate for a certain scope of applications, particularly for those based on real-time data bases. Instead of constructing specific schedules a transformation from processes with age constraints to periodic processes is introduced and a least upper bound to test their schedulability is derived.