Software Engineering Using design RATionale

by Burge, Janet E.

For a number of years, members of the Artificial Intelligence (AI) in Design community have studied Design Rationale (DR), the reasons behind decisions made while designing. DR is invaluable as an aid for revising, maintaining, documenting, evaluating, and learning the design. The presence of DR would be especially valuable for software maintenance. The rationale would provide insight into why the system is the way it is by giving the reasons behind the design decisions, could help to indicate where changes might be needed during maintenance if design goals change, and help the maintainer avoid repeating earlier mistakes by explicitly documenting alternatives that were tried earlier that did not work. Unfortunately, while everyone agrees that design rationale is useful, it is still not used enough in practice. Possible reasons for this are that the uses proposed for rationale are not compelling enough to justify the effort involved in its capture and that there are few systems available to support rationale use and capture. We have addressed this problem by developing and evaluating a system called SEURAT (Software Engineering Using RATionale) which integrates with a software development environment and goes beyond mere presentation of rationale by inferencing over it to check for completeness and consistency in the reasoning used while a software system is being developed and maintained. We feel that the SEURAT system will be invaluable during development and maintenance of software systems. During development, SEURAT will help the developers ensure that the systems they build are complete and consistent. During maintenance, SEURAT will provide insight into the reasons behind the choices made by the developers during design and implementation. The benefits of DR are clear but only with appropriate tool support, such as that provided by SEURAT, can DR live up to its full potential as an aid for revising, maintaining, and documenting the software design and implementation. ii