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Subject: RE: [soa-rm] David Linthicum Says: "ESB versus Fabric.Stop It!"
Having finally now gone through the whole of draft 7 other than the supporting materials, and having gone through all the threads, these sorts of conclusions finally start to be distilled out of it. But, it takes all of the discussion so far, and will take much more I am sure. I like Rebekah's last diagram the most of those so far, but it will still take some more work to reach the ultimate draft for the first version. Ciao, Rex At 1:30 PM -0400 5/25/05, Chiusano Joseph wrote: > > -----Original Message----- >> From: Rex Brooks [mailto:rexb@starbourne.com] >> Sent: Wednesday, May 25, 2005 1:27 PM >> To: Chiusano Joseph; soa-rm@lists.oasis-open.org >> Subject: RE: [soa-rm] David Linthicum Says: "ESB versus >> Fabric.Stop It!" >> >> I think a single service and a single service consumer for >> that service comprise the definition of an atomic SOA. >> Multiple services in a void of service consumers don't make >> an SOA, only the potential for an SOA. We reflect that in >> current thinking in our modeling in the draft 7 of the RM. >> Figures 2 and 2.1, even though 2.1 precedes 2, and 2 shows >> multiple services behind Service A. It might be wise for us >> to have another diagram and arrange it so that the series runs: >> 2.0 Components of a Service, 2.1 Components of a SOA, and 2.2 >> Service Aggregation. > >I like that idea very much. > >Joe > >Joseph Chiusano >Booz Allen Hamilton >Visit us online@ http://www.boozallen.com > >> Ciao, >> Rex >> >> At 9:13 AM -0400 5/25/05, Chiusano Joseph wrote: >> > > -----Original Message----- >> >> From: Duane Nickull [mailto:dnickull@adobe.com] >> >> Sent: Tuesday, May 24, 2005 2:56 PM >> >> To: Michael Stiefel >> >> Cc: soa-rm@lists.oasis-open.org >> >> Subject: Re: [soa-rm] David Linthicum Says: "ESB versus >> Fabric.Stop >> >> It!" >> >> >> >> Endpoints are part of a service description IMO. >> >> Orchestration of multiple services is out of the scope of >> the core >> >> RM, much the same way as how multiple houses are >> positioned next to >> >> each other in a grid layout is un-necessary in order to >> define a RM >> >> for house. >> >> >> >> A service or house do not have to exist amongst multiple >> houses in >> >> order to be services/houses. >> > >> >Which brings us back to what I believe is the single most important >> >question for us to answer: Does one service constitute a >> SOA? Or are 2 >> >or more services required? >> > >> >If 2 or more services are required, then it seems to me that >> in order >> >to call something a *SOA* reference model, the notion of multiple >> >services must be incorporated - as that is the minimal amount of >> >information necessary to *effectively* represent/model the "targeted >> >entity" (which is SOA) for the intended audience. >> > >> >If one service constitutes a SOA, this implies that a SOA >> may have more >> >than one service. It then seems to me that one has a choice for their >> >RM: include only a single service in the model, or include multiple >> >services. The question then becomes which approach enables the most >> >effective representation for the intended audience. >> > >> >So as you see, I believe everything flows from this single most >> >important question. >> > >> >Joe >> > >> >Joseph Chiusano >> >Booz Allen Hamilton >> >Visit us online@ http://www.boozallen.com >> > >> >> Duane >> >> >> >> Michael Stiefel wrote: >> >> >> >> > Could we then conceive of endpoints and orchestration >> in such a > >> >> fashion? Or is the critical point aspect or attribute in >> which case >> >> > endpoint qualifies, but orchestration does not. >> >> > >> >> > To make a grammatical analogy, the RM defines a >> substantive, and >> >> > therefore adjectives (aspects and attributes) are part >> of the RM, >> >> but > verbs (actions) are not. >> >> > >> >> > (side note: I know verbs have aspect, but we are not using the > > >> term > that way). >> >> > >> >> > Michael >> >> > >> >> > At 02:34 PM 5/24/2005, Duane Nickull wrote: > > >> > >> >> >> Since Structural Integrity is an aspect of all houses, >> it could >> >> be >> part of a RM as an abstract concept. Even if you do not >> >> explicitly >> design a house to have a certain set of structural >> >> integrity >> parameters, it still does. It is not a component >> >> itself, just an >> aspect or attribute. >> >> >> >> >> >> Duane >> >> >> >> >> >> >> >> >> Michael Stiefel wrote: >> >> >> >> >> >>> I thought of structural integrity in terms of the >> entire house, >> >> not >>> just a wall, but I think your point remains the same. >> >> >>> >> >> >>> Granted that each architecture needs to specify its >> structural >> >> >>> integrity, but shouldn't the RM have the concept of >> structural >> >> >>> integrity since it is an abstract concept shared by all RAs. >> >> >>> >> >> >>> Michael >> >> >>> >> >> >>> At 02:06 PM 5/24/2005, Duane Nickull wrote: >> >> >>> >> >> >>>> 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 >> >>>>>>> >>> > >> >> > >> >> >> >> >> -- >> Rex Brooks >> President, CEO >> Starbourne Communications Design >> GeoAddress: 1361-A Addison >> Berkeley, CA 94702 >> Tel: 510-849-2309 >> -- Rex Brooks President, CEO Starbourne Communications Design GeoAddress: 1361-A Addison Berkeley, CA 94702 Tel: 510-849-2309
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