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Subject: Re: [soa-rm-ra] An epiphany
I'm a little confused but let's work on it. "private action 'becomes' public" through the real world effects represented by changes to shared state "a complete understanding of the action is only possible in terms of a public/shared semantics" is OK because public understanding is accomplished through publicly available semantics. "you may need description from a ecosystem perspective to facilitate the sharing of the semantics" -- I would say you must have a mechanism to explicitly identify your semantics or there is no way to disambiguate like terms with different meanings, e.g. tank. "descriptions have a facilitating role not an enabling role" is not quite right because there is no other way identified for providing information needed to establish the execution context. How do you intend to convey your intended semantics? Where will folks go to find policies? If message exchange, where do I send messages; if not message exchange, how do we exchange information? "it is not clear to me how much we need to elaborate the structure of such a description" -- exactly what needs to be elaborated in what detail is still an open question, but if the RA is too abstract and too concise, it will help no one. We could get away with this once for the RM but it will even detract from the RM if the RA does not show real connections with the work people have to do. "we may well be elaborating it too deeply; a feeling that Danny has echoed several times" -- at some point we need to go back to our own first principles for developing the RA and evaluate whether certain things get too into the weeds and whether other things are still too in the clouds. We all have our favorite and lesser favorite parts :-) I think there will be a tradeoff in making the document accessible: not too long, partitioned in a way that the readers don't have to hold the whole thing in their heads at once, covering what will keep our audience engaged. To this point, we are still debating individual content. "Systems of systems of systems is not the same as composition of services." But composition of services is one way systems of systems of systems are themselves composed. Ken On Jan 17, 2009, at 11:19 AM, Francis McCabe wrote: > As far as descriptions is concerned ... > > There is this delicious intersection point where a private action > 'becomes' public in the sense that a complete understanding of the > action is only possible in terms of a public/shared semantics. So, > you may need description from a ecosystem perspective to facilitate > the sharing of the semantics. > However, I would note that (a) descriptions have a facilitating role > not an enabling role (an analogy from natural communication: you do > not need a dictionary to speak English, but it helps) and (b) it is > not clear to me how much we need to elaborate the structure of such > a description. In fact, I think we may well be elaborating it too > deeply; a feeling that Danny has echoed several times. > Systems of systems of systems is not the same as composition of > services. It is more about "when in Rome, do as the Romans do..." > Frank > On Jan 16, 2009, at 8:30 PM, Ken Laskey wrote: > >> Dang, Frank, I go away for a couple days and you go all wacko on >> me :-) >> >> OK, my take. Of course it has nothing to do with messages. >> Information has to get from Participant A to Participant B and >> might also depend on information provided by Participants C, D, and >> E. Talking about message exchange buys us three things: >> >> 1) Everybody exchanges messages now and it gives the RA some >> concrete grounding in a space that is familiar to most people. >> >> 2) I expect there is very little if anything messages add to the RA >> than saying you need abstract (and eventually concrete) components >> for message passing and processing if you're exchanging messages, >> but it gives us the incentive to really consider if messages are >> more than a specific use of the SOA machinery that other things >> point out. >> >> 3) I forget right now, but there was a third. >> >> As you note, when you access and want to use information you get >> from someone else, you have to understand it. UDDI is based on the >> assumption that this is not an issue. Obviously, those folks never >> went to an online vendor and tried to make use of the product >> comparison tables. >> >> Description has nothing to do with messages, so getting rid of >> messages doesn't get rid of description. Description does, >> however, critically need semantic engagement. That is one of the >> drivers for the section of description Danny always wants to kill >> because it explicitly points out that whenever you use a term, you >> need to disambiguate the vocabulary being used. This sets the >> stage for mediation which is needed all over the place if >> independent entities are independently creating and providing >> resources. >> >> Your system of systems of systems looks nothing more than >> compositions at various levels and for various types of resources. >> I need more than semantic engagement for the service input values. >> I also need it for policies, for technical assumptions, for ... . >> That is where the execution context comes in because it is the >> collection of the semantic engagements at various levels over the >> various aspects of SOA. >> >> Now I don't see where this cuts the RA in half. If it keeps the >> length manageable, that's a plus, but I don't yet see it. >> >> Ken >> >> On Jan 16, 2009, at 12:24 AM, Francis McCabe wrote: >> >>> Hi Danny, >>> I realize that I have some explaining to do... >>> >>> I don't see Counts-as as being connected to semantic engagement; >>> at least not at the moment. >>> >>> Like I said, this is really about the dichotomy/relationship >>> between private internal action and publicly shared/understood >>> interaction. In my view, the messaging system is, at this level of >>> abstraction, simply a medium in which you can have such a public >>> interaction. It is necessary to have such a medium because we are >>> fundamentally talking about peer-to-peer models crossing ownership >>> boundaries. >>> >>> On top of this, is the strong intuition that one can have multiple >>> layers of ecosystem -- systems of systems of systems etc. >>> >>> One of the diagrams that we have drawn internally is like a spider >>> plant: >>> <Spider Plant.pdf><ATT00001.htm> >> >> ----------------------------------------------------------------------------- >> Ken Laskey >> MITRE Corporation, M/S H305 phone: 703-983-7934 >> 7515 Colshire Drive fax: 703-983-1379 >> McLean VA 22102-7508 >> >> >> >> >> >> >> --------------------------------------------------------------------- >> To unsubscribe from this mail list, you must leave the OASIS TC that >> generates this mail. Follow this link to all your TCs in OASIS at: >> https://www.oasis-open.org/apps/org/workgroup/portal/ >> my_workgroups.php > ----------------------------------------------------------------------------- Ken Laskey MITRE Corporation, M/S H305 phone: 703-983-7934 7515 Colshire Drive fax: 703-983-1379 McLean VA 22102-7508
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