architecture
⟨system⟩ fundamental concepts or properties of a system in its environment embodied in its elements, relationships, and in the principles of its design and evolution
An architecture is what is fundamental to a system — not necessarily everything about a system, but the essentials.
The architecture of a system is cognizant of the system in its environment; the environment determines the totality of influences on the system. One often-cited difference between architecture and design is this: architecture is outwardly focused on the system in its environment; whereas design is inwardly focused once the system boundaries are set.
That which is fundamental to a system may take several forms:
- its elements: the constituents that make up the system;
- the relationships: both internal and external to the system; and
- the principles of its design and evolution.
It is interesting that different architecture communities place varying emphases on these. Software architecture has often been focused on software components as elements and their interconnections as a key relationship. System architecture emphasizes sub-system structures and relationships such as allocation. Enterprise architecture emphasizes principles. The definition recognizes that all of these may play a part in architecture.
In the original edition, IEEE 1471:2000, the definition was:
architecture: The fundamental organization of a system embodied in its components, their relationships to each other, and to the environment, and the principles guiding its design and evolution.
TOGAF embraces but does not strictly adhere to ISO/IEC 42010:2007 terminology. In TOGAF, ‘architecture’ has two meanings depending upon the context:
- A formal description of a system, or a detailed plan of the system at component level to guide its implementation
- The structure of components, their inter-relationships, and the principles and guidelines governing their design and evolution over time
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http://www.iso-architecture.org/ieee-1471/defining-architecture.html