Definition of System Architecture

Defining “architecture” appears to be rather difficult considering the large number of existing definitions. These definitions share some commonality, though in detail differences become obvious. Vitruvius identified three branches of architecture: buildings, time pieces, and machines or mechanics. The importance of principles in architecture fit to the qualitative description that architecture includes everything that is difficult or expensive to change late in the development. This chapter looks at how the concepts of “system,” “architecture,” and “architecture description” relate to each other. Both system element interaction and context interaction can exist independent on architecture. Principles justify at least some architecture decisions since they are regarded as fundamental truth or general scientific theorem. Architecture decisions form a relevant part of architecture. The chapter focuses terms like “functional architecture,” “physical architecture,” “system architecture,” “base architecture,” “logical architecture,” “product architecture” or “system design” regarding definition and relations.