Scalability for graph based CASE tools

Software engineering is particularly concerned with the construction of large systems. Existing software engineering tools tend to be adequate for medium size systems, but not as useful for large and very large systems. This paper presents a model viewing system as the basis for graph based CASE tools which overcomes this lack of scalability. With existing commercial tools the number of user steps to browse or edit a model increases with the size of the model. With the approach of this paper the number of steps remains constant regardless of the model size. In fact, only one step is required for operations such as adding a flow between two processes anywhere in the model, or moving a submodel to a new parent. This paper outlines the approach with a structured analysis example, provides a formal description of the model viewing system, and discusses some limitations