Before we head off into definitions and categorization, lets just ask the question of all questions..."Why does anyone need an IT Architecture?"
Luckily the answer is simple: you need to invest into abstract descriptions of your system because certain qualities do not just arise when you put one functional component next to the other. Architecture tries to achieve sustainability, dependability, scalability, performance, which are many of the things you do not get right the first time you design a system!
Who could be qualified to define the term “IT Architecture”? Assuming that architecture is also a governance discipline we can start with the definition of COBIT (4.1):
Then of course we have to look into the definition of TOGAF which we regard as the most prominent of all modern IT architecture development frameworks. TOGAF states Architecture has two meanings depending upon its contextual usage:
Last but not least we would like to cite Zachmann, who may be regarded as the "father" of Enterprise architecture:
The Zachmann framework defines IT Architecture in terms of its goals, the TOGAF framework defines IT Architecture in terms of its contents. We like both approaches and suggest to combine as follows (in the context of OSA):
Types of IT Architecture
In listening to your IT colleagues you will have noticed that everyone associates something different with the term IT architecture. And because there is no generally accepted taxonomy we will just list the most common terms.
The term “Security Architecture” is introduced in one of the next postings.