Charting the evolution of the Ada Ravenscar code archetypes

In this paper we present the rationale, the status and the planned enhancement of a set of code archetypes that implement common programming patterns suited for the development of Ravenscar-compliant real-time systems. There have been other attempts at building software frameworks that ease the construction of real- time software systems. Ours is not intended for direct access by the user, but for deployment in the back-end code generation engine of a model-based tool environment. A further distinguishing characteristic of our patterns is that they foster the principle of separation of concerns, whereby the functional code of the system (which we require to be purely sequential) stays under the responsibility of the user, whereas the code that realizes the intended concurrency and real-time semantics is obtained by instantiation of predefined, correct by construction, archetypes.