This paper contributes t o the discussions about the development process of Computer Based System by evaluating development principles common practice f o r computer hardware. in this domain, the descriptions can be classified into abstraction levels and views. For computer based systems a similar classification can be identified. This helps t o define the information required at specific points of the development process.For the support of the development of computer based systems an underlying formal model based on Predicate/Transition nets is defined which can be used for simulation and analysis. The applicability of this approach is shown b y a frequently used egample.