Overview of the Lotosphere Design Methodology

This paper presents the direction of work in the Lotosphere Design Methodology. It first examines some basic concepts in distributed systems’ design and then identifies areas for further research and development. In this paper we define and analyse the needs of the design process for distributed systems, in order to determine how the use of a formal design language as LOTOS can improve this process. A top-down view of the design trajectory is used in order to introduce the design goals, and related definitions and concepts. In this context we discuss the role of abstraction as the concept that supports step-wise refinement, and the role of design languages, as the means to represent the relevant properties of a system. A more elaborated design trajectory takes into consideration the deviation cases from the straight top-down model. This analysis ends up at the level of design steps, at which design concerns are identified as the areas of interest: the design methods that comprise the methodology. The paper intends to provide a framework for the effective use of Formal Description Techniques (FDTs) in distributed system design, which is to be applied in the scope of the ESPRIT II Lotosphere Project (Project 2304).