Abstract. Josephs and Udding’s DI-Algebra offers a convenient way of specifying and verifying designs that must rely upon delay-insensitive signalling between modules (asynchronous logic blocks). It is based on Hoare’s theory of CSP, including the notion of refinement between processes, and is similarly underpinned by a denotational semantics. Verhoeff developed an alternative theory of delay-insensitive design based on a testing paradigm and the concept of reflection. The first contribution of this paper is to define a relation between processes in DI-Algebra that captures Verhoeff’s notion of a closed system passing a test (by being free of interference and deadlock). The second contribution is to introduce a new notion of controllability, that is, to define what it means for a process to be controllable in DI-Algebra. The third contribution is to extend DI-Algebra with a reflection operator and to show how testing relates to controllability, reflection and refinement. ...
Mark B. Josephs, Hemangee K. Kapoor