Re: [soa-rm] [issue:structure] draft 07, sect 2, line 201, Figure 2-1

[Michael Stiefel <development@reliablesoftware.com>]

Duane:
         I agree.

Michael

At 10:28 AM 5/19/2005, Duane Nickull wrote:
>Semantics are ubiquitous.  No matter if they are explicit or implicit, 
>they are present.
>Meta data has semantics.
>Metadata is a set of data declaring details pertaining to another set of data.
>I am not convinced that semantics are realized as metadata.  In fact, in a 
>reference model, nothing is realized - it is all abstract.
>
>Duane
>
>
>Gregory A. Kohring wrote:
>
>>Yes "realized as" is not the right phrase here. Would you
>>support "documented in"?
>>
>>-- Greg
>>
>>
>>Peter F Brown wrote:
>>
>>
>>>I like this diagram more. I think it's closer to my understanding at least
>>>of wherewe want to go.
>>>
>>>My only question is: are the semantics *only* realised as metadata? Or more
>>>precisely: in a Reference Model, are the semantics of the service realised
>>>at all? Surely the metadata "realisation" is part of a reference
>>>architecture not a reference model?
>>>
>>>-Peter
>>>
>>>-----Original Message-----
>>>From: Gregory A. Kohring [mailto:kohring@ccrl-nece.de] Sent: 19 May 2005 
>>>09:24
>>>To: Francis McCabe
>>>Cc: SOA-RM; dnickull@adobe.com; mattm@adobe.com
>>>Subject: Re: [soa-rm] [issue:structure] draft 07, sect 2, line 201, Figure
>>>2-1
>>>
>>>Frank,
>>>
>>>If I understand you correctly, then in your view there is little to be
>>>gained by distinguishing between syntaxt and semantics at this level.
>>>Hence, the "Service Description" is purely semantics.
>>>
>>>Attached is another diagram which depicts this idea. Is this consistent with
>>>your ideas?
>>>
>>>-- Greg
>>>
>>>Francis McCabe wrote:
>>>
>>>
>>>
>>>>While I like the direction in which this is going, I have a couple of
>>>>issues:
>>>>
>>>>1. I do not see semantics as being inside service description. 
>>>>Semantics is an abstract concept that may be referred to but is not 
>>>>contained in any description.
>>>>2. I am not sure why data model is broken out in the way suggested.
>>>>To me, tehe data model is an asepct of the semantics of the service.
>>>>3. I do not see a hard and fast distinction between syntax and 
>>>>semantics. Again, any syntactic constraints are simply part of the 
>>>>overall semantics.
>>>>
>>>>The *reason* for this is that while it is tempting to equate
>>>>semantics with application semantics, that is not, in fact, a good
>>>>slope to slip down.
>>>>
>>>>Once you liberate yourself from that misconception, one beings to see 
>>>>all kinds of possibilities. For example, for an encryption/decryption 
>>>>service, its entire semantic model consists of messages with
>>>>encryption markers etc. etc. Is that syntax? Depends on your point of
>>>>view; to my mind it is semantics of a simple service.
>>>>
>>>>
>>>>Frank
>>>>
>>>>
>>>>On May 13, 2005, at 12:01 AM, Gregory A. Kohring wrote:
>>>>
>>>>
>>>>
>>>>
>>>>>Yes, this looks much better. Attached is a slight variation which 
>>>>>moves the semantics into the description. At one time, "syntax" was 
>>>>>also explicitly mentioned as being part of the description. Has that 
>>>>>been dropped?
>>>>>
>>>>>-- Greg
>>>>>
>>>>>Duane Nickull wrote:
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>>Does something like this make more sense than a stack diagram.   This is
>>>>>>uses a multi-layered approach to group things and reduce the  number 
>>>>>>of lines.
>>>>>>
>>>>>>Duane
>>>>>>
>>>>>>Duane Nickull wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>>The issue we had with the concept map is we ended up with a 
>>>>>>>proliferation of arrows for items like "semantics" and security  since
>>>>>>>they are omni-present.   We tried various other depictions and  finally
>>>>>>>came to the stack.  I agree that the stack alone is not  sufficient 
>>>>>>>and also lends itself to ambiguity so we agreed to place some text by
>>>>>>>
>>>it.
>>>
>>>
>>>
>>>>>>>There are standard conventions for interpreting stack diagrams.
>>>>>>>For example - layers in the stack are only able to talk to adjacent 
>>>>>>>layers.  Layer n can interact with n-1 and n+1, but not n+2.
>>>>>>>
>>>>>>>The position of the vertical layers indicate they are relevant to
>>>>>>>each horizontal layer they are adjacent to.
>>>>>>>
>>>>>>>In stack diagrams, there is no named associations present so it is 
>>>>>>>ambiguous.
>>>>>>>
>>>>>>>Accordingly, one can infer the following from the diagram in 2.1
>>>>>>>
>>>>>>>Service descriptions (are associated with) services Policies (are 
>>>>>>>associated with) service descriptions Contracts (are associated 
>>>>>>>with) policies data models (are associated with) contracts semantics 
>>>>>>>(are associated with) service descriptions, policies, contracts and 
>>>>>>>data models.
>>>>>>>Services, Service descriptions, policies, contracts and data models 
>>>>>>>may all be discoverable and their presence and availability known.
>>>>>>>
>>>>>>>What I do not like is that it also separates the data model from the 
>>>>>>>service description and separates the contract from the service description.
>>>>>>>
>>>>>>>It may be better to go with a layered concept map.
>>>>>>>Duane
>>>>>>>
>>>>>>>
>>
>>