Explaining Embedded Software Modelling Decisions

As today´s devices, gadgets and machines become more intelligent, the complexity of embedded software controlling them grows enormously. To deal with this complexity, embedded software is designed using model-based paradigms. The process of modelling is a combination of formal and creative, design steps. Because of the partially non-formal character of modelling, the relation between a model and the system cannot be expressed mathematically. Therefore, the modeller´s justification that the model represents the system adequately can only be non-formal. In this paper we discuss the nature of non-formal modelling steps and pin-point those that create a ´link´ between the model and the system. We propose steps to structure the explanation and justification of non-formal modelling decisions. This in turn should enhance confidence that the non-formal, physical world surrounding the embedded system is adequately represented in the model.