Maintainability

This report summarizes how to systematically analyze a software architecture with respect to a quality attribute requirement for maintainability. The report introduces maintainability and common forms of maintainability requirements for software architectures. It provides a set of definitions, core concepts, and a framework for reasoning about maintainability and the satisfaction (or not) of maintainability requirements by an architecture and, eventually, a system. It describes a set of mechanisms, such as patterns and tactics, that are commonly used to satisfy maintainability requirements. It also provides a method by which an analyst can determine whether an architecture documentation package provides enough information to support analysis and, if so, determine whether the architectural decisions contain serious risks relative to maintainability requirements. An analyst can use this method to determine whether those requirements, represented as a set of scenarios, have been sufficiently well specified to support the needs of analysis. The reasoning around this quality attribute should allow an analyst, armed with appropriate architectural documentation, to assess the risks inherent in todays architectural decisions in light of tomorrows anticipated needs.