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RE: Web Service Definition [Was "Some Thoughts ..."]

From: James M Snell <jasnell@us.ibm.com>
Date: Fri, 1 Mar 2002 14:50:13 -0700
To: www-ws-arch@w3.org
Message-ID: <OF8B843798.7378E560-ON87256B6F.0077D084@boulder.ibm.com>
Someday I'll remember that replyTo on W3C mailing lists is screwed up ;-) 
... I sent this to Stephen a few minutes ago.

- James M Snell/Fresno/IBM
    Web services architecture and strategy
    Internet Emerging Technologies, IBM
    544.9035 TIE line
    559.587.1233 Office
    919.486.0077 Voice Mail
    jasnell@us.ibm.com
 Programming Web Services With SOAP, O'reilly & Associates, ISBN 
0596000952 

==
Have I not commanded you?  Be strong and courageous.  Do not be terrified, 

do not be discouraged, for the Lord your God will be with you wherever you 
go.  
- Joshua 1:9
---------------------- Forwarded by James M Snell/Fresno/IBM on 03/01/2002 01:48 PM ---------------------------
   James M Snell                03/01/2002 01:44 PM

To:     "Vinoski, Stephen" <steve.vinoski@iona.com>
cc: 
From:   James M Snell/Fresno/IBM@IBMUS
Subject:        RE: Web Service Definition [Was "Some Thoughts ..."] 

First off, a Web resource is an object, a tangible thing.  Every object 
has a description, or a collection of metadata about that object, that 
describes it's properties.  A Web service is no different.  A Web service 
has properties that can be described as metadata.  For example: the URI, 
what it does, the types of messages it can receive, the transport 
protocols it supports, etc.  Because a Web service has properties, a Web 
service can be described.  The only variable is HOW you describe the 
service.

Description Function: Given a Web Resource, the Description D is the 
function D(m) where m is the set of all metadata about the Web resource.

Now, would we agree that all Web resources have, at the very least, a URI? 
 The URI indicates the identity of a Web resource.  We should also agree 
that every resource has a specific addressable location. Discovery is 
merely the task of resolving a URI to its addressable location where the 
resource can be found.  Again, the only variable is HOW.

Discovery Function: Given a Web Resource, the Location L is the function 
L(uri) where uri is the URI of the Web resource. 

- James M Snell/Fresno/IBM
    Web services architecture and strategy
    Internet Emerging Technologies, IBM
    544.9035 TIE line
    559.587.1233 Office
    919.486.0077 Voice Mail
    jasnell@us.ibm.com
 Programming Web Services With SOAP, O'reilly & Associates, ISBN 
0596000952 

==
Have I not commanded you?  Be strong and courageous.  Do not be terrified, 

do not be discouraged, for the Lord your God will be with you wherever you 
go.  
- Joshua 1:9

To:     James M Snell/Fresno/IBM@IBMUS
cc: 
Subject:        RE: Web Service Definition [Was "Some Thoughts ..."]



I challenge you to prove it. "100%" is an awfully strong statement.

--steve

> -----Original Message-----
> From: James M Snell [mailto:jasnell@us.ibm.com]
> Sent: Friday, March 01, 2002 3:57 PM
> To: Vinoski, Stephen
> Subject: RE: Web Service Definition [Was "Some Thoughts ..."]
>
>
> 100% of all Web resources, including Web Services CAN be
> described and
> discovered.  The differentiating factor is HOW.  Every Web
> service CAN be
> discovered regardless of whether or not the Web service explicitly
> supports a specific discovery mechanism.  Every Web service CAN be
> decribed regardless of whether or not the Web service
> explicity supports a
> specific description mechanism.  You are right in that decription and
> discovery alone do not distinguish Web services from other
> types of web
> resources, but that does not mean that the properties of
> discoverability
> and description are not part of the formal definition of a
> Web service.
>
> - James M Snell/Fresno/IBM
>     Web services architecture and strategy
>     Internet Emerging Technologies, IBM
>     544.9035 TIE line
>     559.587.1233 Office
>     919.486.0077 Voice Mail
>     jasnell@us.ibm.com
>  Programming Web Services With SOAP, O'reilly & Associates, ISBN
> 0596000952
>
> ==
> Have I not commanded you?  Be strong and courageous.  Do not
> be terrified,
>
> do not be discouraged, for the Lord your God will be with you
> wherever you
> go.
> - Joshua 1:9
>
> To:     James M Snell/Fresno/IBM@IBMUS, "Joseph Hui"
> <jhui@digisle.net>
> cc:     <www-ws-arch@w3.org>
> Subject:        RE: Web Service Definition [Was "Some Thoughts ..."]
>
>
>
> > -----Original Message-----
> > From: James M Snell [mailto:jasnell@us.ibm.com]
> > Sent: Friday, March 01, 2002 1:21 PM
> > To: Joseph Hui
> > Cc: www-ws-arch@w3.org
> > Subject: RE: Web Service Definition [Was "Some Thoughts ..."]
> >
> >
> > A Web Service must be defined as having the properties that
> it can be
> > decribed and discovered.  Both the Web service and it's
> > description must
> > be discoverable.
>
> No, and no. This thread of email already contain multiple explanations
> of why.
>
> > Definition ==> A Web service can be described and discovered.
>
> As I've already explained using real-world examples, neither
> of these is
> necessarily true (other than the discovery via URI that Mark
> mentioned).
>
> Neither discovery (as in UDDI-like services) nor description
> distinguish
> Web Services from prior art, nor are they found in 100% of
> existing Web
> Services systems. They are therefore not needed to define Web
> Services.
>
> --steve
>
> >
> > - James M Snell/Fresno/IBM
> >     Web services architecture and strategy
> >     Internet Emerging Technologies, IBM
> >     544.9035 TIE line
> >     559.587.1233 Office
> >     919.486.0077 Voice Mail
> >     jasnell@us.ibm.com
> >  Programming Web Services With SOAP, O'reilly & Associates, ISBN
> > 0596000952
> >
> > ==
> > Have I not commanded you?  Be strong and courageous.  Do not
> > be terrified,
> >
> > do not be discouraged, for the Lord your God will be with you
> > wherever you
> > go.
> > - Joshua 1:9
> >
> > Sent by:        www-ws-arch-request@w3.org
> > To:     <www-ws-arch@w3.org>
> > cc:
> > Subject:        RE: Web Service Definition [Was "Some Thoughts ..."]
> >
> >
> >
> > By now IMHO we the WG have made the progress that D&D ought to be
> > in the def.  (Have we not?  I don't want to be presumptuous here.)
> > So the issue to be settled is whether D&D is already accounted for
> > in URI.
> >
> > In my view URI is for addressability.  A globally unique ID offers
> > no intrinsic value to a resource's discovery.  E.g. there's no way
> > johny, seeking to buy books, can discover a book seller by
> > inferring from a URI like http://www.amazon.com.
> > Mark's made some good points; yet I find the
> > "D&D-accounted-for-in-URI"
> > argument too tenuous.  Withi the web context, D&D is an integral
> > (as Sandeep put it) part of WS.  It's not a property that can be
> > assumed by default, thus calling it out is warranted.
> >
> > Cheers,
> >
> > Joe Hui
> > Exodus, a Cable & Wireless service
> > =========================================
> >
> > > -----Original Message-----
> > > From: Mark Baker [mailto:distobj@acm.org]
> > > Sent: Friday, March 01, 2002 6:53 AM
> > > To: Sandeep Kumar
> > > Cc: Vinoski Stephen; Joseph Hui; www-ws-arch@w3.org
> > > Subject: Re: Web Service Definition [Was "Some Thoughts ..."]
> > >
> > >
> > > Sandeep,
> > >
> > > > If D&D are not an integral part of a Web Service defintion,
> > >
> > > I was claiming that discoverability *is* an integral part of the
> > > definition.  It's just already accounted for by defining
> that a Web
> > > service be URI identifiable.
> > >
> > > I know this is a bit different than some Web service work
> > people have
> > > already done, but this is (IMO) one of those times where our
> > > mandate to
> > > be integrated with Web architecture effects our work.
> > >
> > > > pl help me define
> > > > how would you define a Web (or a Network) of Web Services,
> > > the participants.
> > > >
> > > > At a high-level, they must at least have the same
> > > characteristics. If not,
> > > > it would be much harder to reason about them
> > semantically, deal with
> > > > managing & monitoring them.
> > >
> > > Sorry, I'm unclear what you're asking.
> > >
> > > MB
> > > --
> > > Mark Baker, Chief Science Officer, Planetfred, Inc.
> > > Ottawa, Ontario, CANADA.      mbaker@planetfred.com
> > > http://www.markbaker.ca   http://www.planetfred.com
> > >
> >
> >
> >
> >
>
>
> 
Received on Friday, 1 March 2002 16:50:22 GMT

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