Design reuse and scale:: Keys to practical code generation and large scale software maintenance

We advocate the reuse of design knowledge rather than code as the most Effective means for obtaining productivity and quality improvements in software engineering activities. This knowledge comes in several forms: domain analysis, generative knowledge, and knowledge of the structure of a particular system in terms of the domain and how domain concepts are implemented. We are building and using a practical large-scale software (re)engineering tool, the Design Maintenance System (DMS) that implements these ideas. Reusing design knowledge, DMS is able to automate many interesting engineering activities: analysis, reverse engineering, forward synthesis, and eventually software maintenance via Design Maintenance. Code reuse methods are incapable of providing strong support for these activities. However, many issues involved in DMS construction are driven by the scale of the problem: number of languages, sheer code volume, amount of knowledge involved, and computational energy required.