A sequential real-time refinement calculus

We present a comprehensive refinement calculus for the development of sequential, real-time programs from real-time specifications. A specification may include not only execution time limits, but also requirements on the behaviour of outputs over the duration of the execution of the program. The approach allows refinement steps that separate timing constraints and functional requirements. New rules are provided for handling timing constraints, but the refinement of components implementing functional requirements is essentially the same as in the standard refinement calculus. The product of the refinement process is a program in the target programming language extended with timing deadline directives. The extended language is a machine-independent, real-time programming language. To provide valid machine code for a particular model of machine, the machine code produced by a compiler must be analysed to guarantee that it meets the specified timing deadlines

A Specification Oriented Semantics for the Refinement of Real-Time Systems

1 Introduction calculation ifications and executable programs can be formulated. A real-time functional specification in TAM is transformed step-by-step into a mixed program containing both specification fragments and executable code. Such transformations continue until a completely executable program is produced which is guaranteed correct with respect to the original specification. The program may then be analysed by run-time schedulability and allocation tools in the usual manner, and executed. The paper introduces a computational model for real-time systems, conservative extensions to first-order predicate logic to cover time, a wide spectrum language with a specificational semantics, a refinement calculus, and an example of program development. A computational model should reflect the intended target application area, and also define what we mean by terms such as `termination', `communication', `concurrency ', `functionality', and in our case `refinement' as well. In doing so, i..