• Perceivable Architecture: the Architecture which is somehow directly or indirectly perceivable in a real System, as determining the range of performance and Cost Attributes possible. This applies regardless of who, if anyone, consciously specified the Architecture design artifacts.
• Inherited Architecture: Architecture which was not consciously selected at a particular Level of Architecture activity, but was either:
- incidentally inherited from older systems,
- accidentally inherited from specified design artifacts, specified by architects, managers or engineers.
• Specified Architecture: the formally defined Architecture specifications at a given Level and lifecycle point, including Stakeholder Requirements interpretation, Architecture specification, Engineering specification done by this Architecture Level, certification criteria, Cost estimates, models, prototypes, and any other artifact produced as a necessary consequence of fulfilling the architecting responsibility.
Note: an extensive discussion of the Architecture Concept is given in Maier02, including a special appendix on the history of attempts to define a Standard in DoD, IEEE, INCOSE. Appendix C pp283-9. In addition the book gives a great many other insights into the nature of the Concept.
Note: XE "Architecture [Noun]." *202.Architecture [noun] XE "*202.Architecture [noun]"
The highest specified Level of design ideas for a defined System is called the ‘architecture’. The Architecture is the collection of controlling design ideas for a defined purpose. The Architecture refers primarily to frameworks, interfaces and other technology and organizational ideas which more-detailed design ideas are expected to fit in to.
1. The Architecture specifications (*617) would probably be classified as Generic design constraints (or ‘architecture constraints’, if you wanted to emphasize the Idea of ‘architecture’).
2. Architecture specifications would have Priority over subsequent design decisions, made at more-specialized Engineering levels.
3. ‘Architecture specification’ is the set of system-wide decisions, which are made in order to improve the systems survival ability, as it is threatened by changes to it, and by its environment.
Architecture: A high Level design that provides decisions about:
• purpose (What problem(s) that the Product(s) will solve)
• Function description(s) (Why has it been decomposed into these components?) • relationships between components (How do components relate in space and time?) • dynamic interplay description (How is control passed between and among components?) • flows (How does data or in-process Product flow in space and time?) • Resources (What Resources are consumed where, in the Process or System?). Source: Standard: FAA-iCMM Appraisal Method Version 1.0 A-19, INCOSE Conference CD, June 1999, Brighton UK FAA98
This definition differs from Planguage in that we are primarily concerned with design aspects, and this contains three Requirement notions.
Δ %%% (delta, symbol pyramid architecture) Note keyed and drawn icon for design ( a subset of architecture is a rectangle (or [Design X] ) which is analogous to the blocks used to make the pyramid)
History of Concept