An Interactive Software System for Computers-Aided Design: An Application to Circuit Project The characteristics of an interactive software system, intended to constitute an interface between designer and computer during various steps of the design process, are presented. The main emphasis is given to the description of the features of the two high level user oriented languages, operating at different levels, on which the interaction is based. The first one is IMOL, an interactive monitor language, which is designed to perform the overall and control functions of the software system; its design criteria provide the user with commands which are both simple and efficient in order to perform all the functions needed in computer-aided circuit design. The second one is COIF, a circuit oriented graphic language, which is designed to describe, generate, and manipulate graphic problem specifications; it is an extension of Fortran with graphic-type variables, so that the designer who is familiar with Fortran need not learn a new language. The application to computer-aided circuit design is in particular examined; on the other hand, the adopted design criteria provide sufficient generality to extend the use of the two languages to different computer-assisted applications. CACM September, 1970 Bracchi, G. Somalvico, M. interaction, graphics, computer graphics, computer-aided design, circuit design, software system, software organization, language, monitor language, graphic language, extended Fortran 3.24 3.25 4.13 4.22 4.3 CA700902 JB February 10, 1978 2:20 PM 1853 4 2003 2003 4 2003 2003 4 2003 2003 4 2003 2002 4 2003 2152 4 2003 1710 5 2003 1767 5 2003 2003 5 2003 2003 5 2003 2003 5 2003 2105 5 2003 2230 5 2003 2003 6 2003