Abstract
The software architectures of safety and mission-critical systems are designed to satisfy and balance an exacting set of quality concerns describing characteristics such as performance, reliability, and safety. Unfortunately, practice has shown that long-term maintenance activities can erode these architectural qualities. In this paper we present a novel solution for preserving architectural qualities through the use of Tactic Traceability Information Models (tTIMs). A tTIM provides a reusable infrastructure of traceability links focused around a commonly implemented architectural tactic, as well as a set of mapping points for tracing the tactic into the architectural design and the implemented code. The use of tTIMs significantly reduces the effort needed to create and maintain traceability links, provides support for visualizing the rationale behind various architectural components, and delivers timely information to maintainers so that they can preserve critical architectural qualities while implementing modifications. Our approach is described and evaluated within the context of a mission-critical software-intensive system.