Modeling and analyzing hardware-software interfaces with ComMA

Technical diversity of a complex system can be reduced using modularity and interface management. At the multi-disciplinary system level, this can be modelled using MBSE (Model-Based System Engineering) where typically the focus is on the system structure with the components and their interfaces. At the mono-disciplinary level this is further refined where each discipline uses its own tools and techniques to include more behavioural aspects. Frequently this leads to problems during the integration phase, especially for interfaces where multiple disciples are involved. In this report, we address the integration problems of hardware-software interfaces. We investigate whether the ComMA methodology helps to clarify hardware-software interfaces, to remove ambiguities, and to detect issues with such interfaces early during development. As a case study, ComMA is applied to the interfaces of a component of a Philips MR scanner. For reasons of confidentiality, the interfaces of the component are described in an abstract way as a client interface that needs sensor data and a sensor interface to obtain data. The implementation of the component has been instrumented to obtain logs of component execution during a few experiments. The main focus is on specifying and analysing two aspects: (1) the timing behaviour of the interfaces, and (2) the relation between the two interfaces, expressing that the client receives recent data. We show how the monitoring features of ComMA provide insight in the implementation of the component and lead to questions about the design. The experiments also revealed useful information about recently added ComMA features and wishes for future improvements. Moreover, we briefly address the relation between MBSE and ComMA.