Hartmut's BoxHartmut Wilms’s Weblog

« April 2005 | Main | September 2005 »


SOA, who art thou?

Rich Turner, Radovan Janecek (VP of Engineering at Systinet) and Clemens Vasters are musing about the definition and “existence” of SOA.

I agree with Radovan Janecek’s overall definition of “an enterprise architecture that follows SO principles”. An even better definition would be “Software Architectures that follow SO principles, cause there is no single true service-oriented architecture. Software architectures depend on the requirements and constraints at hand. Although two systems might be realized with SO principles in mind, the underlying architectures will most certainly differ in one or the other aspect - regardless of the tools used to implement these systems. Thus a concrete architecture (including tools, practices, components, communication stack, protocols, notation) which adheres to SO principles is an instance of the “SOA” concept.

This leads to two main questions (among many others):

a) What are the SO principles?

b) What are the identifying features of a service oriented architecture (making them adhere to SO principles)?

The first question has been discussed by several people for a long time. The four tenets are a very popular definition. Although I do not completely agree with them they are a good starting point.

Whereas the first question kept many people busy thinking and talking about, the answer to the second one has been avoided by almost everyone. Although architecture is mainly concerned with abstraction it is more concrete than principles and paradigms. Architecture nails down principles to “concrete” concepts, practices and patterns. This blog entry is no exception to the philosophical and abstract discussion about SOA and SO. I will try to elaborate on architecture and the SO principles in the near future.

The point I’m trying to make is that SOAs exist, or even better, will have to be designed in order to make service-orientation feasible. I really like Rich Turner’s comments about Microsoft dissociating from a SOA solution. SOA is not a product! Vendors have to provide tools and “components” which maybe adapted/configured in order to implement a SOA. No Vendor will be able to provide a one size fits all SOA.

Posted by Hartmut Wilms at 22:45 | Comments (5) | TrackBack