As a participant of many discussions on Enterprise Architecture – the most insightful I had the opportunity to take part in as a member of the Open Group Architecture Forum – I found that attempting  to define terms like “Enterprise Architecture” or “Business Architecture” tends not to result in conclusion. While part of these divergencies are due to different contexts of the participants, most of them seem to stem from the ambiguous semantics associated both with the construct of a compound in English language, as well as with the ambiguous use of the word “architecture”[1].

In the following, I try to evaluate the semantic dimensions of “architecture” compounds – as a framework for structuring discussions, and facilitating communication. Subsequent postings will evaluate divergent interpretations of terms commonly used in the context of enterprise architecture, and provide recommendations how to handle these interpretations in interactions between architects.

Please contribute your own views on how the word architecture is used. It will be extremely interesting to gather additional aspects of the term.

Kind Regards

Thomas Obitz - Principal Architect

Composing “Architecture”

Within the IT community, the term “architecture” traditionally is used in one of three ways: One is as a characterization of an object (the “architecture” of a cathedral), the second is to describe the process of designing these architectures[2].  The third meaning – the profession of the architect – today is derived from the second[3].

In the characterizing context, an XYZ architecture can be (without claiming completeness)
·         the architecture of an XYZ (Enterprise Architecture - Architecture of an Enterprise)
·         an architecture for an XYZ (Enterprise Architecture - Architecture for an Enterprise)
·         an architecture describing the XYZ aspects of something (Information Architecture - Architecture describing the information assets of an Enterprise)
·         an architecture describing the aspects of “something” which are relevant for (constructing) an XYZ (Information System Architecture)
·         an architecture consisting of XYZs (Process Architecture - Architectural description consisting of process models)
·         an architecture in the state XYZ (Target Architecture)
As an art, we find “XYZ architecture” as
·         architecture using an XYZ approach (Enterprise Architecture – doing architecture using Enterprise Architectual approaches, even for a smaller unit than an enterprise, or for a government)

Architecture of an XYZ (constitutional)

 ISO 1471 talks about the “architecture of software intensive systems”, which was usually abreviated into “software architecture”. This straightforward interpretation has been transferred to the field of Enterprise Architecture only recently. The “Architecture of an Enterprise” therefore may describe the relevant aspects of an enterprise, the way an organization is structured, how its departments interact, and how they generate value.

Architecture for an XYZ (demarcational)

 The terms “Enterprise Architecture”, “Departmental Architecture” or “Line of Business Architecture” can be used to describe the scope an architecture is relevant to. An “industry architecture” is an architecture not of, but relevant to a specific industry. If used in this way, “Enterprise Architecture” does not explain what aspects it describes, but just that it applies to the enterprise as a whole. This missing description, however, can be inserted between the two terms: An Enterprise IT architecture describes the IT landscape for the enterprise, an Enterprise Data Architecture its data assets.

Architecture describing the XYZ aspects of something (projective)

 “Enterprise Business Architecture” can be used to describe the business aspects of an organization, i.e. the aspects related to achiving its vision and purpose. Enterprise Information Architecture describes the information related aspects of an organization, including their relationship to other architectures.
This use of XYZ architecture focuses on the aspects of architecture related to a specific concern. It therefore comprises the projection of architecture to a viewpoint or set of viewpoints, and hence is highly dependent on stakeholder concerns.

Architecture describing the aspects of “something” which are relevant for (constructing) an XYZ (contextualized)

 When John Zachman wrote his famous paper “A framework for Information Systems Architecture”[4], he spoke about much more than just information systems. His framework considers the context in which an organization builds such systems, and which influence their gestalt.
It is common to perform such contextualization in many compositions of the term architecture, and this approach can be considered as an extension of the constitutional use of the compound.

Architecture consisting of XYZs (compositional)

 When talking about “Process Architecture”, we are by and large talking about a documentation set composed of process documents. A similar thinking is behind the (outdated) perception of data architecture as a corporate data model.

Architecture in the state XYZ (state)

 Using the terms “as is” or “target” architecture describes a state in the development of architecture.

Architecture using an XYZ approach (method)

Architecture organized in an XYZ fashion (organizational setup)

Federated architecture is a way of performing architecture activities in a specific organizational setup. It can be used both for architectural deliverables (where deliverables of a higher level are detailed at the next level) as well as for a way of doing architecture (with a defined distribution of responsibilities between layers).