Problems, promises and performance: some questions for real-time system specification

Abstract

This paper considers how different views of real-time program specification and verification arise from different assumptions about the representation of time external to the program, the representation of time in the program and the verification of the timing properties on an implementation. Three different views are compared: real-time programming without time, the synchrony hypothesis and asynchronous real-time programs. Questions about the representation of time are then related to different models of time and their roles at different levels of analysis. The relationship between the development of a program from a specification and its timing characteristics in an implementation is discussed and it is suggested that the formal verification of timing properties can be extended towards the implementation. The need for fault-tolerance in a real-time system is then considered and ways examined of incorporating a formal proof of fault-tolerance along with proof of its timing properties.Keywordsreal-time specificationsynchronous real-timeasynchronous real-timefault-tolerance