INFORMATION SCIENCES 48,195-215 (1989) 195 A Framework for Efficient IC/VLSI CAD Databases* H. C. DU and S. GHANTA Department of Computer Science, University of Minnesota, Minneapolis, Minnesota 55455 ABSTRACT CAD databases have been used to store design data and to integrate design tools in K/VLSI design systems. However, the requirements for a “good” CAD database are much more complex than those for a conventional database. Due to both the complexity of various design processes and the enormous amount of data involved in a practical CAD database, we believe that a two-level hierarchical database including a global database and a set of local databases is necessary. In this paper, we propose a framework for such CAD databases. We concentrate on the overall system architecture. 1. INTRODUCTION Design is the activity of realizing a system through either a systematic or at times an ad hoc procedure from the specifications of the system under develop- ment. Computer aided design (CAD) is a design process wherein the human designer is assisted by a computer in bookkeeping, consistency checking, and expanding the level of detail of the subsystems, using algorithms so as to decrease the tedium involved in the development of complicated practical systems. Integrated-circuit (IC) design is the process of realizing a system in the form of a set of mask layouts to enable the construction of the IC chips that will meet the given specifications. Due to the sheer complexity of the design of VLSI systems, say at the gate or transistor level, and due to the quick turnaround-time requirements of practical systems, it is often impossible for any human being to carry out the VLSI *This work was supported in part by a grant from MEIS and by the NSF Grants MIP-8605297 and DCR-8420935. OElsevier Science Publishing Co., Inc. 1989 655 Avenue of the Americas, New York, NY 10010 OOZO-0255/89,‘$03.50