Steve Jones wrote:
> Well my trite answer is "b(u)y my book". My longer one is that for me
these have _always_ been what
> I've seen as the services and the job of IT is to deliver as
appropriate to that service.
Well, I took your advice and read your book. It has lots of good stuff,
and I agree that SOA must be business driven.
Here are some thoughts:
1. I think that a prerequisite for any "service architecture" work must
be an understanding of the need for (or possibility of) change to the
business, and at least some consensus on what such a change might be.
Moreover, there must be a credible story that SOA can be the path to
achieving this change. In other words the business WHY should be first,
not third as shown in the diagram on page 10. Otherwise I fear there
will be a lot of senior level people in the room saying "Why are we
doing this?"
2. The approach described in the book for defining an enterprise service
architecture is essentially one of "top-down decomposition". However, I
suspect that structure of services for a given business is probably not
unique, and its form will depend on the business rationale (drivers) for
undertaking the whole exercise in the first place. This is another
reason for putting the WHY first.
3. I was concerned that the definition of service too vague. The
examples of Level 0, 1 service maps looked to me much like traditional
functional decomposition diagrams. Is there any difference, at this
level, between a "business service" and a "business function"? At the
bottom of page 57 there is the rather alarming suggestion that
"Customer" can be viewed as a service. I would be concerned about
attempting to create a service architecture without a clear idea of what
can qualify as a "service".
4. I some ways, what you describe looks like a methodology building a
business strategy. However, there are other considerations that need to
be included in the formulation of business strategy, such as:
- Best practices on the industry
- Competitive position, opportunities and threats
- Assessment of corporate strengths, weaknesses and aspirations.
I would think that these need to be considered in any exercise that
has an enterprise-wide scope and impact.
Notwithstanding these comments, I am quite sure that value is only
obtained from SOA by taking a business perspective, and driving the work
from a clear articulation of the business objectives is the only way to
succeed.
Rgds
Ashley
