An Architectural Model For Time Awareness . Ediz. Italiana

Since three millenniums philosophers, poets, writers, scientists and engineers debate about time. Computer scientists and practitioners too have been obliged to face the concept of time. In computer science time and speed seldom emerge as basic abstractions. The lack of such abstractions leads to the development of tricky code that heavily depends on platform mechanisms, intermixes design choices and implementation details, can be hardly tested and maintained. The key idea behind our proposal is that time should be a full-fledged first-class concept, which directly turns into basic architectural abstractions. The abstractions provide mechanisms, not policies, so that an application can define its own policies by exploiting knowledge both about the domain and about its own behaviour. We propose a model for building time aware software architecture and we exploit such a model to design and implement RTOM. RTOM is a concrete reference architecture for the design of systems able to manage and reason about their own temporal behaviour at the application level. RTOM exploits time and speed as first-class architectural concepts. The conjecture is that this approach may help designing and implementing real-time systems, where the control of the timing and of the speed plays a major role. Finally, a simple test-bed dealing with the real-time processing of a stream of images shows that the approach is sound and allows the principles of the control theory to be applied to the reflective management of the system behaviour.