Schema: An Architecture for Knowledge Based CAD,

Abstract : Schema provides an integrated environment for all aspects of the synthesis and analysis of electronic designs from PC boards through circuit and mask design of VLSI devices. It simplifies the development of synthesis and analysis tools by using uniform data structures and by making available libraries of standard routines and advanced control structures appropriate for CAD tool development. Because all tools in the Schema environment utilize the same abstract data structures it is easy for tools to interchange data about a design or even pieces of the design itself. Schema also permits much of the design to be done in a technology independent fashion by allowing the designer to delay implementation decisions until the last possible moment. The information associated with a particular component of a design is organized as a module. Modules contain schematics, icons, topologies, layouts, simulation results, and other descriptive information for this component. The descriptions contained in modules are implemented as procedures which utilize other modules in a hierarchical fashion. (Author)