Mode changes are a crucial characteristic of a number of real-time systems . Ada does not easily deal with these events and hence it has been argued tha t language changes are required ; in particular the introduction (or strictly speakin g the re-introduction) of asynchronous exceptions . In this paper we present an idio m for programming mode changes . Moreover we argue that this structure can b e implemented efficiently .

No abstract

Re-introduction of asynchronous exceptions into the Ada language has been suggested as a means to solve certain problems in intertask communication. The author argues that such re-introduction would provide inconsistent and nondeterministic semantics, disallow several important classes of optimization, cause considerable distributed overhead, complicate program proof and verification efforts, prove error-prone to use, and offer little new functionality. Further discussions of alternate solutions to the requirements which motivated asynchronous exceptions are encouraged.

No abstract

No abstract