Successful use of rate monotonic theory on a formidable real timesystem

摘要

The navigation payload software for the next block of GlobalPositioning System satellites recently completed testing. The computerprogram for the onboard computer is sufficiently complex to exposealmost every issue that has been put forward in rate monotonic theory.The success of this effort demonstrates the utility of the theory inthis type of application. The system designed required the processor toperform a highly diverse set of hard deadline real-time functions. Thisdesign would have been difficult or impossible prior to the developmentof rate monotonic theory. The use of utilization bounds has importantadvantages from a software engineering point of view. The problems ofinsuring schedulability over the course of development and verifying theschedulability of the finished system are discussed