What is an Architectural Description?
The framework defined by John Zachman is very useful as an analytical tool, but it is difficult to use on a standalone basis. Part of the problem is that it defines primitive elements and models, not composite models. In a sense, it is similar to the Periodic Table of Elements in chemistry. It is useful, and necessary, to have an understanding of the elemental structure of things, but most of the world involves the use of molecules and higher level compounds that are mixtures of elements. For practical purposes, we tend to move back and forth between dealing with compounds and their constituent elements.
The answer to this in the Enterprise Architecture Tool Suite is to provide integrated support for additional frameworks that are not as comprehensive or precise as the Zachman Framework, but which are well accepted in the Systems Engineering community as being sound, and which have more practical value in developing composite models. Then, the tools suite supports easy navigation back and forth between the composite models and their constituent elements. Switching viewpoints and frameworks can be accomplished by moving from a composite framework, to the constituent elements, and from the elements to other views and frameworks that provide perspectives on the same elements. This provide a 360 perspective and definition of the role of the element in the enterprise, and it provides a means of verification and validation that the models are accurately describing the enterprise, either in the way it is desired to operate, or in the way it currently functions. This is similar to reviewing specifications for a building and moving through different views and schedules (plans, elevations, perspective drawings, schedules of details and scale models) to obtain a 360 degree view of the envisioned structure.
One of the additional frameworks integrated into the tool suite is a formal scheme for the specification of what constitutes an “architectural description,” or what we term an architectural blueprint, or simply a blueprint. The tool suite uses the conceptual framework of ANSI/IEEE-1471-2000 Recommended Practice for Architectural Description of Software-Intensive Systems for this purpose. IEEE-1471 is well documented and defines best practice in the information systems realm and is widely usable beyond the software-intensive systems domain .
The second additional framework integrated into the toolset is a popular scheme for documenting systems architecture by means of “views” as described by Philippe Kruchten as the “4+1 View.” The views defined by Kruchten define a baseline set of views that fit within the framework of IEEE 1471. We use them as a foundation blueprint specification in the tool suite.