Tuesday, July 15, 2008

Clouds and Clocks 4

An interesting debate on SaaS and Control

Gianpaolo starts out by suggesting a simple trade-off between user control and the economics of scale. With SaaS, the user forgoes some control, in order to benefit from (some share of) the economics of scale achieved by the service provider. Gianpaolo divides control into two aspects: Control of Features and Control of SLA.

Charlie thinks it comes down to a perspective of what is "control". He suggests a different notion of control, whereby a contract with a service provider would give you more legal control than doing the work in-house.

But as far as I can see, both of them are talking about Command (setting the target conditions) rather than Control (regulating the system to satisfy the target conditions). See Alberts and Hayes, Understanding Command and Control (pdf).

Gianpaolo associates the Control of Features with who builds the service (Implementation) and the Control of SLA with who runs the service (Deployment). (This is a bit of a simplification; I shall ignore that for the moment.) But in Service-Oriented Architecture, there is a third and perhaps the most important role: who specifies the service. It is possible for the user (or a community of users, or an independent regulatory body) to provide the specification, and for the provider merely to deliver an acceptable implementation and deployment. Returning to the distinction between Command and Control, we may associate the Command of both Features and SLA with who specifies the service.

But what kind of service are we talking about here? The economics of scale are most obviously associated with simple one-size-fits-all services that are symmetric and replicable - what Philip Boxer calls r-type services. In most cases such services are unilaterally specified by the service provider, offer little if any contextual variety to the service user, and control tends to focus on quality control and cost control.

With more complex types of service, the service user typically demands a much greater fit to a specific use-context, and the question of control expands to include requisite variety and the economics of governance. But does this mean that the economics of scale go out of the window? The challenge for very large and complex service-based systems is to combine the economics of scale AND scope AND governance.

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