Re: [soa-rm] David Linthicum Says: "ESB versus Fabric.Stop It!"

[Duane Nickull <dnickull@adobe.com>]

The RM does not necessarily have to get into cardinality rules IMO, 
unless they are very obvious.  In the case of a house, you may not make 
consistent rules stating that every house has to have at least three 
walls since a wall can be curved or any number of walls from 3 up.  You 
may be able to infer from the relationships that there is a certain 
cardinality if the RM for a house said that each room has one door.  
That would declare an association between the number of rooms to the 
number of doors.

Structural integrity is an aspect of a wall, which must be specialized 
for each architecture based on a number criteria.  The RM declares what 
the wall is and its' purpose, the architect has the job of specifying 
the actual walls to be used for each architecture and ensuring they map 
back to requirements.

You are right - analogies are not definitions, however I have found them 
very useful in conveying the meaning.

Duane

Michael Stiefel wrote:

> Does the RM understand that some of the concepts are unique and some 
> multiple (without an exact number, you could have one circular wall, 3 
> walls, 4 walls, etc.)?
>
> Using your analogy, how does the RM deal with concepts such as 
> structural integrity. Structural integrity would apply to all house 
> RAs. In my way of thinking concepts such as endpoints or orchestration 
> are analogous to this.
>
> In the analogy I would see the reference architecture as Colonial 
> American Reference Architecture, or even more specifically Colonial 
> American Cape Ann, or Colonial American Greek Revival reference 
> architectures.
>
> Analogies are useful, but they are not definitions.
>
> Michael
>
> At 12:56 PM 5/24/2005, Duane Nickull wrote:
>
>> RA means Reference Architecture.  As per the previous emails on this 
>> subject, it is a generalized architecture.
>>
>> The relationship is that architects use a RM as a guiding model when 
>> building a RA.
>>
>> For example, if you are architecting a house, an RM may explain the 
>> concepts of gravity, a 3D environment, walls, foundations, floors, 
>> roofs, ceilings etc.  It is abstract however.  There is nothing 
>> specific like a wall with measurements such as 8 feet high.  Note 
>> that the RM has only one each of these things - it does not have 4, 
>> 16, 23 walls, just one as a concept.
>> The architect may uses this model to create a specific architecture 
>> for a specific house (accounting for such things as property, 
>> incline, climate etc) or an architect MAY elect to use it to build a 
>> more generalized reference architecture.  The latter is often done by 
>> architects who design houses.  When they sell a house, they must 
>> often re-architect the RA for specific implementation details such as 
>> incline of land, climate, facing the sun etc..
>>
>> So why do we need a RM?  Simple - we now have logical divisions 
>> amongst the components of a house and what they mean.  That way, when 
>> a company says " we are a flooring company..", that is meaningful 
>> since we all know what that means.  The same applies to a roofing 
>> company.  Without the basic consensus on the logical divisions, a 
>> roofing contractor may also try to include the ceiling and walls as 
>> part of his offerings.
>> That would not work and not allow the general contractor to build a 
>> house very easily since there may not be consensus upon the division 
>> of labor and components to build the house.
>>
>> Do you guys think an explanation of this nature may be good to 
>> include in the introduction section?
>>
>> Duane
>>
>> Chiusano Joseph wrote:
>>
>>> What is an RA? What is the relationship between an RM and an RA? 
>>> What is
>>> the RM->RA path for SOA?
>>>
>>> Matt also submitted last week (I believe) that we may not even need an
>>> RA. How should that change our notion of RM, if at all?
>>>
>>> Joe
>>>
>>> Joseph Chiusano
>>> Booz Allen Hamilton
>>> Visit us online@ http://www.boozallen.com
>>>
>>>>
>>>>
>
>