A Design Rule Database System to Support Technology-Adaptable Applications

This paper describes aspects of a CAD system which has been specifically designed to support technology-adaptable applications and to incorporate expert system processes where appropriate. The approach advocated in the paper is to use design rules stored in a database to supply technology related information to CAD tools. Design rules currently supported in the database are concerned with different aspects of design, such as timing, loading and layout. These rules are described in a special-purpose language, DRDL. Technologies are organised hierarchically and, in principle, the design rules assigned to a particular technology may be inherited by all its descendants. Selective access to rules by application programs may be made using attributes to qualify rules and hence to control focus of attention.