Using LOTOS in a Design Environment

Implementation of reactive systems is recognized as a difficult problem in the field of computer system engineering. Much of this difficulty arises due to the interactions between many components executing concurrently and the distributed nature of many of the systems. This paper describes an approach which can be used for the design of such systems and how LOTOS was integrated into this approach. The design approach involves alternating between structural design and behavioural design with LOTOS being the language used for formally specifying behavioural design. Different styles of specification can be used for defining the behaviour of a set of interconnected components, and this paper introduces a new style, the slice style, which describes behaviour as interactions propagating through a set of components. A number of problems were encountered regarding the expressiveness of LOTOS; the problems encountered as well as the proposed solutions are presented.