The Data Structure Manager (DSM) combines object-oriented programming with semantic data modeling concepts in the context of the C language. DSM is a full-featured object-oriented language which includes single and multiple inheritance, class descriptor objects, metaclasses, choice of method binding time, error handling, persistent objects, modularity, and an interactive interpreter in an efficient manner. In addition, DSM supports the association and aggregation relationships as part of the Object Modeling Technique (OMT) used for conceptual design. DSM has been used since 1986 to build a variety of research and production-quality software such as an advanced CAF/CAD system.