The requirements of complex, high-performance computer systems have changed computer-design methods dramatically: Today, digital-system design is based on state-of-the-art semiconductor technology, highly integrated ICs, and custom LSI technology - all of which make CAD tools indispensable. Many CAD systems meant for the production of computer components have been announced by digital-system manufacturers, and the advanced technology built into these systems makes it possible to design large and complex computer systems that incorporate custom LSI. The integrated design system devised at NEC Corp. to create the SX-1 and SX-2 supercomputers includes CAD tools. It follows three strategies (engineering work-station utilization, thorough design verification in the early stages of design, and the use of CAD tools to establish design flow) for realizing the four main features required of CAD systems (short design time, high productivity, high-quality design, and a user-friendly interface to the CAD system). This design method made it possible for NEC to develop the SX-1 and SX-2 in a relatively short time. The SX-1 and SX-2 are entirely composed of custom LSI technology that is, for the most part, integrated into multichip packages (MCPs). This design influenced the form of the CAD system and CAD tools heavily because the fourmore » features required in the CAD system resulted from it and the strategies were proposed from an analysis of the required features. The LSI technology necessitated both improvements in productivy and high-quality design; in addition, since NEC was developing not only LSI technology but also the computer system that would make use of it, an integrated CAD system covering the physical levels from LSI to system was necessary.« less