Monday 9 December 2002

Minimum Set of Architectural Models

So how many (static) models does it take to show an IT architecture without overcomplicating the issue?


John Zachman's framework http://www.zifa.com  would have us using 30, but I am sure that John would not advocate quite such an array of toys as a fundamental architecture toolkit for system architects (although I would fully advocate using this framework as a coverage checklist). My team had developed a four model approach to recording and showing target IT architectures which cover




Business functionvalue chain elements
DataCore business entities plus Master / Slave relationships
Technical Application Layersmax 5  tiers, Presentation, Presentation Logic, Business Logic, Middleware services, Data

Infrastructure
the reuseable component model including all the basic stuff like networks, O/S, file systems etc

This seemed to work well until along came the Web services model where we are supposed to think in terms of floating service interfaces around a set of business functions (objects). This led us to develop a new Interfaces Model which can represent these arbitrary connections between systems. In developing this model we have discovered that it is the key which can hold the others together by providing the mapping across the models which would normally be handled "in the head". I think we may be on to a canonical form for static IT models.
Is anyone else trying to figure out how to record, design and track architectural models at a high level of abstraction?
Next we need to tackle the problem of identifying quality and value proposition for a given interface.

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