"extensions" and "features"

[GILBERT PILZ <gilbert.pilz@oracle.com>]

It seems to me that, when we talk about extensions, we do so using at 
least two different levels of granularity. At the finer, more detailed, 
level of granularity we tend to talk about individual, additional 
attributes to existing resource types or individual, new resource types. 
For example, "The Assembly Template resource has been extended with a 
'zone' attribute" or "We've added the Zone resource as an extension".

At the coarser, less detailed, level we tend to talk about features and 
functions that support use cases above and beyond those covered by the 
CAMP spec. For example, "This CAMP implementation supports the 
geographic zone extension" - meaning that the CAMP implementation in 
question has extend 3 resource types with an extension attribute and 
added one new resource type - plus all the logic that implements the 
semantics of "geographic zones".

As a matter of personal preference, I dislike using the same term to 
refer to different concepts, particularly when those concepts exist at 
different layers of abstraction. Furthermore, I think the differences in 
these two concepts have practical implications on how we support 
"extensions" in CAMP. Specifically, I think there are use cases that 
involve both of these concepts, sometimes individually, and sometimes 
together. In any case, I would like to continue to refer to the 
finer-grained concept as "extensions" and refer to the coarser-grained 
concept as "features". For example, "The geographic zone feature is 
implemented using extensions to the Assembly Template, Application 
Component Template, and Platform Component Template resource and the 
extended Zone resource".

~ gp