You can't help getting the impression from Kerrie Holley, IBM's CTO of its SOA Center of Excellence, of how much the idea of services remain the underpinning of what we're trying to do. That's true whether you're talking about restructuring the enterprise data center, implementing a simple Web service, invoking software-as-a-service such as Salesforce.com, or go straight to cloud computing.Holley stopped into InformationWeek's offices in San Francisco on Monday to swing the conversation away from Amazon's EC2, Microsoft's exciting new cloud data center in Chicago and such topics back to his favorite subject, services oriented architecture.

Enterprises are still focused on SOA, says Holley. They're not trying to rewrite every legacy system but with new development or when a piece of restructuring goes on, they apply a services orientation, says the head of IBM's SOA Center of Excellence.

SOA is a term that struggled to get established in the 2002-2003 timeframe, was overtaken by the notion of new standards for Web services, and has tended to get pushed into the background whenever the discussion turns to cloud computing. But in fact, these are not separate and distinct things. They're all related. The thinking behind SOA guided the implementation of Web services; the example of standard operation of Web services was extended into the conceptualization of cloud computing. Now coordinating services in the data center with services in the cloud is one way to think about the "hybrid cloud."

In the Nov. 30 issue, I tried to describe How Cloud Computing Changes IT. One reader wrote in, "The article refers to a hybrid cloud scenario blending private and public clouds. I don't see that happening," he said. Small businesses will resort to cloud computing, but large enterprises will stay away from the external cloud suppliers, he predicted

Holley disagreed. "I think big enterprises are going to be as much a consumer of (external) cloud computing as small ones." As SOA matures inside the company, it will make it easier to coordinate with external services and resources, he said.

Holley is one of IBM's 65 active distinguished engineers who became an IBM Fellow, and it's easy to see why. He's is co-patented the first SOA development model and the first SOA maturity model, where services graduate through distinct patterns of use until they gain intelligence for their own operation. They can use the feedback from sensors and intelligent agents as guidance on what to do. They become aware of the context in which they're operating. Needless to say, we're not there yet. The Open Group has adopted his Service Integration Maturity Model as a standard and in November 2008, produced its 1.0 draft of the Open Service Integration Maturity Model, or OSIMM.

Today it's still an art but Holley and others are trying to make the creation of services subject to a strict modeling methodology and a more rigorous implementation process. In the end a set of services will underlie each key business process, and an ability to vary them in the model will mean a way to quickly adjust and adapt the business process itself.