Tuesday, March 20, 2007

SOA Sweet Spot

In a post entitled Your SOA is JABOWS, Microsoft's Nick Malik identifies what he calls the SOA Sweet Spot, which represents the intersection of two areas.
  1. Typically, the greatest benefits of IT come from automating processes that execute often. It may be hard to cost-justify an n-person-year project to automate some process, if that process only occurs once a year, or on an exceptional basis.
  2. Typically the greatest benefits of SOA come from supporting automation in areas that change frequently. As I said in my fourth post on BPM and SOA, the business case for SOA typically becomes stronger as the volatility increases.
Nick expresses this as a two-by-two matrix with Frequency of Occurrence along one axis and Frequency of Change along the other axis. The sweet spot is then in the top right quadrant.

Someone called Malcolm Anderson posted a comment to Nick's blog, challenging the difference between Frequency of Occurrence and Frequency of Change. Nick replied with a simple retail illustration.

Of course, if you choose to regard everything as undifferentiated process, then the two dimensions of Nick's matrix possibly collapse into a single dimension. This may be the point behind Malcolm's comment. Nick's matrix depends on an articulation of two different types of variation at two different logical levels - equivalent to the item and the batch (manufacturing) or the phenotype and the genotype (biological evolution). SOA allows us to implement a stratified solution in which these two types of variation are decoupled - yielding both economics of scale (based on frequency of occurrence) and economics of scope (based on frequency of change). This is of course an architectural solution, one which demands true SOA rather than JBOWS.


By the way, the term JBOWS appeared in an article by Joe McKendrick: The Rise of the JBOWS Architecture (or Just a Bunch of Web Services) (September 2005). Bobby Wolf of IBM (who picked up the term via James Governor) prefers to call it JaBoWS. I happen to prefer to stick with the term JBOWS, if only because an Internet search for Jabows yields all sorts of other stuff I'm not interested in.

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