Formal Specification and Verification for Real-Time Scheduling Based on PAR.

Scheduling are playing a key role in many real-time systems. The goal of this paper is to apply PAR and its transformation rules to formal specification and verification of real-time scheduling. We formally described three constraints for uniprocessor systems and five constraints for multiprocessor systems. Furthermore, an EDF (Earliest Deadline First) program, written in Apla abstract modelling language, could be automatically transformed to an executable program. Finally, correctness of the EDF program was formally verified by using new strategies of developing loop invariant in PAR and Dijkstra’s Weakest-Precondition theory. Formal specification of schedule constraints for real-time systems highlights PAR’s powerful descriptive ability. Development and verification an EDF scheduling algorithm embody the efficiency and reliability role of PAR Method and PAR Platform.