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Subject: RE: [soa-rm] explaination of RM to RA etc.


What is the "it" in this phrase? The "something" or the "instance" The RA?
If you mean "once an instance of a (reference?) architecture can be
implemented, that architecture is no longer abstract": I don't like the word
abstract popping up here...maybe I just need a holiday. Anyway, once an
instance can be implemented it is obviously not abstract (if an instance
cannot be implemented, is it an instance? Sorry, but terminology is going to
haunt us all the way...)

To say that an RM "must not be able to be implemented" is tautological and
possibly confusing. Its purpose is to conceptualise the necessary "building
blocks" and how they should be used together, no more, so inevitably it
cannot be implemented as that is not its function: it is a bit like saying
that "bricks and mortar must not be able to be implemented": you will get
those who will respond: "of course I can, I just need some blueprints,
building standards and guidelines, and a few willing workers and we can
build that castle...", but that's not our point. The point is that an RM
describes the what (and the why), but not the how.

The RA on the other hand should provide the how - not of a specific
implementation - but generically: does that mean the RA is (or is not)
abstract? Not sure it's helpful...For example, is an MDA-based Platform
Independent Model a reference architecture? If so, is it abstract? I don't
think so, but it is generic: it can be implemented in different (platform
specific) manners.

So, RM, always abstract; RA, sufficiently detailed to enable *any*
(conformant) implementation but sufficiently generic as to not prescribe any
*particular* implementation

Peter
(not yet on holiday but wishing he was...)

-----Original Message-----
From: Duane Nickull [mailto:dnickull@adobe.com] 
Sent: 06 July 2005 01:11
To: flinn@alum.mit.edu
Cc: soa-rm@lists.oasis-open.org
Subject: Re: [soa-rm] explaination of RM to RA etc.

Don:

As I understand the term, once an instance of something can be implemented,
it is no longer "abstract".  (Please - someone correct me if I am wrong).


Therefor, to answer your questions:


Don Flinn wrote:

>Duane
>
>I have a few questions.
>
>1. How abstract can/should the RA be?  IMO the more abstract the 
>broader the coverage of potential, derived, concrete architectures.
>  
>
DN - It must be able to be implemented.  The RM, by its abstract nature,
must not be able to be implemented.  This has and will continue to confuse
many people with no architectural or OO knowledge.

>2. Do you mean the Profiles to be specific, abstract aspects of the RA?
>  
>
DN - Can you please elaborate?

>3. I'm not sure of the meaning of Related Models in this context.
>  
>
DN - if someone decides to model the network aspects of an RA using the OSI
reference model or if they also add in "process oriented" aspects into the
architecture, these models might be considered related.  I had not decided
on specific tests to determine the qualification of that labeled
association, however would enjoy any thoughts you, or anyone else has.

Cheers

Duane (back from vacation and TOTTTTTTAAAALLLLY  relaxed).

>
>Don
>
>On Wed, 2005-06-29 at 11:46 -0700, Duane Nickull wrote:
>  
>
>>This is a graphic I developed this morning to depict how a RM may 
>>relate to an SOA Framework.  Not sure if it is helpful or if we want 
>>to pursue something like this in a separate white paper.
>>
>>Any comments would be appreciated.
>>
>>Duane
>>    
>>
>
>  
>




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