Computer-aided design for custom integrated systems

The computer-aided design (CAD) system described herein was developed to aid in the design of digital systems to be implemented by custom integrated circuits (CIC) and multi-chip hybrid custom integrated systems (CIS). The terms MSI/LSI are avoided here due to the general confusion which exists in the literature as to what constitutes an MSI/LSI circuit. The CAD system philosophy is that each CIC is implemented from a selected set of "library elements". This design approach results in some size inefficiencies, compared with manual designs, but provides many advantages, of which flexibility and a shortened design cycle are the most important. This CAD system captures fundamental design information in a machine-readable form early in the design process, thus maximizing potential computer assistance and minimizing costly and time-consuming errors. This paper contains an overview of the complete CAD system, highlighting its more distinctive features. The complete system has been operational on a 360/30 for several months, and specific experiences with it can therefore be discussed.