Re: [soa-rm] Capability vs Function

[Rex Brooks <rexb@starbourne.com>]

Thanks for getting the separate thread going, Jeff,

I don't quite agree. Unfortunately "unit of work" doesn't quite capture 
what I associate with "function." Function for me means "performance of 
an operation", but I could live with "performance of a unit of work" if 
we narrow the scope to business functions.

However just to bring up some obvious definitional nuances... When my 
eyes function properly, the operation of my sense of vision is achieved, 
even if the unit here is continuous successful performance. I noted 
"successful" in my example because there is always a range or spectrum 
of efficiency also associated with almost any function. Admittedly, some 
are booleans, e.g. you're either pregnant or not in terms of fulfilling 
the function of reproduction. However, I'm sure we all see the 
difficulties in coming to agreement on this one. We have to accommodate 
ranges of efficiency over time with the same definition that satisfies 
true or false at any given point in time.

Anyway, it should prove to be an interesting discussion.;-)

Cheers,
Rex



Estefan, Jeff A (3100) wrote:
>
> RM Colleagues,
>
> I noticed that we use the terms “capability” and “function” throughout 
> the RM and in the various proposed updated definitions of SOA service 
> but we are not clear on the distinction between the two. One of the 
> most succinct definitions I’ve seen for capability is something along 
> the lines of “A capability is an ability to do something based on 
> expertise and capacity.” This would imply that a capability is 
> measureable and I believe that to be true.
>
> I have yet to find a satisfactory definition of a function but perhaps 
> in this context we could argued that a function represents (the 
> non-physics meaning of) a “unit of work” and that the plural functions 
> would represent the performance of multiple units of work. The 
> challenge will be to distinguish this from related concepts such as 
> “activity” or “action.” Open to other interpretations but we need at 
> least some notional interpretation of what we mean by function.
>
> Either way, the two concepts of capability and function are related 
> but are not synonymous. Perhaps we could be a little more precise in 
> our definition of capability and consider the following:
>
> “A capability is the ability to perform a function or set of functions 
> based on expertise and capacity.”
>
> <SIDEBAR>This is intended to be a separate but related e-mail thread 
> intended to try and get us all on to a common level of understanding 
> on these related concepts as they are fundamental to the general 
> definition of service that we’ve been discussing in a separate 
> thread.</SIDEBAR>
>
> Cheers!
>
> - Jeff
>

-- 
Rex Brooks
President, CEO
Starbourne Communications Design
GeoAddress: 1361-A Addison
Berkeley, CA 94702
Tel: 510-898-0670