Note: While dealing with conceptual representations of enterprises, the words architecture and framework are used quite often. WG1 (ISO TC184 SC5 WG1, Modeling and Architecture) realizes that reviewers may embrace a different definition for either term. That is fine; however, WG1 invites reviewers to share them. WG1 feels that when WG1 uses these terms in the enterprise-representation context, that WG1 should use a consistent and consensus definition for these words. A discussion follows about each term and its definition.
This presentation is posted by the WG1 Convener prior to being considered by WG1. Detailed discussion of this topic by WG1 is planned after the CD14258, Guidelines and Rules for Enterprise Models, is issued for ballot in the spring of 1996. One goal of WG1 is to define a strategy and presentation scheme for a family of standards covering necessary aspects of enterprise representation. To do that we will need a strong consensus of the meaning of the terms architecture and framework as applied to WG1 work.
Each definition presented below is divided into two parts, first a generalized definition of the term, and second, as the term applies or is applied to enterprise representation.
Perhaps a reason the definitions for these terms often have been transposed or treated as synonyms is because they share a common meaning element in one domain of their usage. This common element is the concept of arrangement. Both terms denote, in one sense of their usage, an orderly or basic arrangement of some kind of system. For architecture the arrangement sense is the endpoint or result of applying the style and method part of the definition. For framework the arrangement refers to a kind of beginning, or a structure for supporting or enclosing the subject item. This framework then becomes a tool or a part of a system as it is constructed. There can, therefore, be a framework for an architecture to help classify the components of that architecture. In the same manner, a framework can be constructed using a style and method; that is, using architecture.
One solution could be to designate as a framework any representations having to do with arrangement; and to designate as architecture the process of eliciting the art, science, style, and methodology of creating something.
Nature of Architecture: An architecture may exist at two levels, one at a conceptual level; the other at a physical level.
Physically, architecture refers to the structure of the end product of architectural work--the target system.
Conceptually, it is the art, science, method, and style of building something. In this sense, architecture is not a physical thing or a component of something. It is an abstract concept that encompasses many categories of principles. Architecture is the art, science, method, and style of building something that fulfills the practical and expressive requirements of a group of humans. Architecture is a mental reality derived from sense perception. The objective of architecture is purposeful organization. There are some features that distinguish an architecture from other artifacts; it:
Individuals or groups create architectures to fulfill their specifications. Users, who set the goals, establish different types of architecture, not the architects. Architectures tend to be stable, and to change an architecture, a need must exist that exceeds economic considerations, because repetition is less expensive than experiment and innovation. In an architecture, standardization of elements can be useful to achieve financial saving or, more importantly, an architectural value. A good architecture creates an attractive appearance and connotes the intended message to the beholder. The thing being built using a good architecture should not only be structurally stable but should also appear to be stable.
Style: Architectures convey a style that communicates the outlook of a culture and the concepts of its architects. The principal forces in the creation of a style are:
These forces act to produce an evolution, or life cycle, within every style and, ultimately, they act to generate new styles that tend to supersede their predecessors.
Expression communicates the particular values of style. Components of expression are content and form. Content can be communicated only through form. Content is concrete and specific, while form is an abstract expression of qualities. Content is the subject matter of architecture. Content interprets the functions and techniques of buildings. When architectural forms become the vehicle of content, the forms are symbolic. For example, spires denote a church. They also may connote religion, pleasant religious experience, and on to other concepts, each of them individual and personal.
Symbols: Humans can comprehend by associating the meaning (semantics) of symbols (signs and concepts) that are new as well as those that are known. The structure of language (syntax) permits endless new meanings by retaining a fairly constant vocabulary. The meaning of architectural symbols or of words may even change but the process must be logical or gradual. If change is irrational, the purpose--communication--is lost.
In the similarities discussion above, there is mention of a shared-meaning element between architectures and frameworks: an arrangement. The life-cycle activities of a system development during which an arrangement becomes available, occurs toward the end of the system-definition activities and toward the beginning of the physical-realization activities. This is where the physical arrangement aspect of architecture and the structural arrangement aspect of framework converge.
Given this, to define framework one may assume, therefore, that there exists a relevant architecture. This architecture, among other things, defines a framework--the limiting structure and its supporting members--of the thing being built. The framework is the defining real-world manifestation of a portion of the abstract notion of architecture. A framework is a basic structure; a frame of reference, or a systematic set of relationships. The framework does not include the art, science, style, and methodology required to develop the system, only the scope of the system and an arrangement of the components. A framework may be a structural frame, a skeleton, or a supporting system; or a set of components, standards, or principles governing behavior, thoughts, actions. In a mathematical context only, a frame of reference is a system of, often othogonal, geometrical, axes for defining position. The choice of a framework depends on the purpose of the endeavor.
Architectures supply the body of topical facts and knowledge, and frameworks define the scope, the interfaces, and the components.
The thing that enterprise analysts, designers, operators, and maintainers need is a reference architecture that is known and developed to the extent that one enterprise can find a way to use another enterprise's architecture, for whatever reason. Whether this can be done best by standards, by clever software design, or both, is something that must be investigated and discussed. The things we have with which to work are the enterprises, that comprise tools, material, energy, information, and labor; frameworks; enterprise models; suggested or required methodologies; and guidelines and rules for using each. The enterprise architecture, or enterprise-reference architecture, is the organization of all of these things. It is the body of topical facts and knowledge about enterprises. This will include the art, science, methodology, and style of developing an enterprise.
An enterprise-reference architecture should point toward purposeful organization of enterprise concepts. The architecture should have a set of characteristics apropos to enterprise analysis; namely it:
The enterprise-reference architecture does not need to have a geometric shape, or orthogonal axes; it could be a document that organizes, logically, many details about an enterprise, including its intended expression, its purpose, and how it operates.
To be complete an architecture must contain the guidelines and rules for an enterprise framework; a definition of the component (module, system, or building-block) types; and a definition of available components, that should be contained in the resulting structure. When complete the architecture should incorporate the above characteristics.
The architecture, among other things, defines the framework--the limiting structure, its supporting members, the components, and the interfaces of the thing being built. In other words, the framework defines the scope of the instance of the architecture being planned and its elements. An enterprise framework is an orderly set of standards or principles governing behavior, organization, processes, resources, communication, and information; that give reference, meaning, orientation, or viewpoint to an enterprise and the system and subsystems related to it. Since an operating enterprise is a dynamic thing a framework should include some kind of system of reference, from which enterprises in operation, in transition or in equilibrium, are studied.
As with the enterprise-reference architecture, the framework does not need to have a geometric shape, or orthogonal axes; it could be a document or a matrix that defines areas of an enterprise that should be addressed during an analysis.
Frameworks
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Edited by: JG Nell, TC184 SC5 WG1 convener ( nell@nist.gov.), updated 30 September 1996