[soa-rm-ra] RE: Service & Capability

[Rex Brooks <rexb@starbourne.com>]

Yup.

Cheers,
Rex

At 10:07 AM -0800 1/30/09, Estefan, Jeff A wrote:
>Hi Jim,
>
>We never really fully defined "capability" in 
>the RM.  Instead, we took the approach that it 
>meant more or less the "ability to do 
>something."  A little vague admittedly, but 
>certainly OK from an abstract RM perspective.
>
>People usually associate doing something with 
>functionality; hence, capability and 
>functionality are often used synonymously when 
>talking about services.  In my opinion, 
>capability goes beyond just the ability to do 
>something (i.e., functionality) but also how an 
>offering (e.g., service) performs that 
>capability; in other words, its quality 
>attributes.  And both (functionality and quality 
>attributes) should be part of that offering's 
>advertised description.  If not, how do I as a 
>consumer decide whether or not the offering is 
>going to meet my needs?
>
>The distinction between capability and real 
>world effect was essentially taken from the 
>perspective that the former is an a priori 
>notion (i.e., what the service can do or is 
>suppose to be able to do prior to invocation) 
>and the result of invoking the service to 
>realize the capability.  The latter we refer to, 
>of course, as real world effect.
>
>Clearly, a real world effect cannot occur unless 
>there is some action or set of actions performed 
>by an initiator (consumer) and an action or set 
>of actions performed by the receiver (service). 
>This is why we introduced the concept of "joint 
>action" in the RA.  In other words, there has to 
>be a speaker and a listener in order for 
>something to happen (i.e., real world effect to 
>occur).
>
>You do raise a good point between the two uses 
>in 4.3.2 and 3.3.1 that we would should try and 
>do a better job of aligning.  Neither statement 
>is really wrong per se, it's just that it would 
>be better if we could be a little more clarity 
>on the relationship between action (or joint 
>action), capabilities, and real world effect as 
>you've suggested.  Something we should take the 
>action to resolve before the next public review 
>draft.
>
>CheersŠ
>
>  - Jeff


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Rex Brooks
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Starbourne Communications Design
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