Global Analysis: moving from software requirements specification to structural views of the software architecture

Software architecture design approaches typically treat architecture as an abstraction of the implemented system. However, doing so means that the concepts, languages, notations, and tools for architecture are much more closely related to those of detailed design and implementation than to those of software requirements. Thus the gap between requirements and architecture represents a paradigm shift, while that between architecture and detailed design does not. Global Analysis, which is part of the Siemens Four Views architecture design approach, is a set of activities that serves to reduce the magnitude of this gap by guiding the architecture design process, capturing design rationale, and supporting traceability between requirements and architecture. In this paper Global Analysis is re-examined in light of five years of teaching it, reflecting on it, comparing it to other approaches, and examining how it was applied in four new systems. This experience confirms the value of the Global Analysis activities and the importance of capturing its results. In some cases the benefit went beyond that envisioned, and in other cases Global Analysis was not applied as expected. Because the templates that are provided for Global Analysis results have such a strong influence on how the activities were performed, this will be the focus of future changes.