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Subject: FW: [ogsi-wg] RE: [ws-caf] WS-Resource Framework


Your postman at work again.

--
Savas Parastatidis
http://savas.parastatidis.name (now blogging)
 

> -----Original Message-----
> From: Vambenepe, William N [mailto:vbp@hp.com]
> Sent: Monday, January 26, 2004 5:19 AM
> To: Mark Little; Jeffrey Frey; Ian Foster
> Cc: Newcomer, Eric; ogsi-wg@gridforum.org; Savas Parastatidis; ws-
> caf@lists.oasis-open.org
> Subject: RE: [ogsi-wg] RE: [ws-caf] WS-Resource Framework
> 
> 
> Hi Mark,
> 
> I agree with most of what you are writing, but I don't think I made my
> main point clear in the first email.
> 
> First thing, when I say WSRF, I don't mean the "modeling state" white
> paper. I mean the white paper plus the specs that come with it. That's
> the framework. And actually, I mean the specs more than the white
paper
> because that's where the normative content is. I see WSRF as providing
a
> set of features that are useful for a specific, and very common, way
of
> using Web services. These features are described in the specs
(published
> and unpublished).
> 
> What WSRF (in either the white paper or the specs) does not say is:
this
> specific header has to show up in your messages to ensure correlation.
> To the contrary, WS-Context describes a specific header
(wsctx:context)
> that has to appear in the messages. This is what I mean when I say
that
> WSRF and WS-Context are orthogonal. And there are many things that
WSRF
> (in the different specs that compose the framework) does and
WS-Context
> does not do, such as access to properties, grouping of resources,
etc...
> In that sense too, they are orthogonal.
> 
> For example, if you put yourself in the shoes of a developer who needs
> to expose and access properties of a resource through Web services,
you
> have two questions to answer (among others):
> - what header format am I going to use in my messages to carry the
> information identifying what resource I am interested in?
> - how am I going to format my request to retrieve a specific property?
> WS-Context is one possible answer to the first question.
> WS-ResourceProperties (the relevant part of WSRF here) is one possible
> answer to the second question. But the way I answer the first question
> is irrelevant to the way I answer the second and vice-versa. I could
> pick my own, homegrown, correlation header format instead of
WS-Context,
> it wouldn't change my ability to use WS-ResourceProperties. So they
are
> orthogonal.
> 
> I wrote:
> > > To a large extent WS-Context and WSRF are orthogonal.
> > WS-Context defines
> > > a way to convey, in messages, the fact that some of these
> > messages are
> > > related to one another. WS-Context doesn't care about what
> > this means.
> 
> You replied:
> > I don't understand why you say that WS-Context doesn't care
> > about what the
> > information means. Are you saying that the sender of a WS-R
> > message cares
> > about the endpoint data in a different manner? The sender of
> > a WS-Context
> > enhanced message would do just the same thing.
> 
> What I say is WS-Context the *specification* doesn't care. Obviously
the
> developer that uses WS-Context cares. But WS-Context (the spec) just
> says "Mr. developer, I'll tell you how to place messages into a
context;
> what you use that mechanism for (security session, access to stateful
> resource, message correlation) is none of my business". So WS-Context
> doesn't care about the meaning of the context it allows the sharing
of.
> 
> BTW, you are right to correct me when I write: "WS-Context defines a
way
> to convey, in messages, the fact that some of these messages are
related
> to one another". Indeed this is technically a bit too restrictive and,
> as you pointed out, a WS-Context header can be useful even if it is
> carried by only one message. [My wording came from the way we defined
> Conversation in WSMF (WSMF, not WSRF, see
> http://devresource.hp.com/wsmf/)]. But this really wasn't my point one
> way or the other, my point was that, as I wrote above, WS-Context
> specifies what correlation header goes in the message and WSRF does
not.
> 
> I wrote:
> > > WSRF doesn't specify how the messages are correlated. The
> > only thing it
> > > specifies is how to create an endpoint reference that
> > indicates how the
> > > messages are correlated.
> 
> You replied:
> > This sentence doesn't seem to parse. The reason I'm confused
> > here is you say
> > that WS-R doesn't say how messages are correlated only how
> > the messages are
> > correlated? Do you mean it only provides a means of correlation at
the
> > service? If so, I've also shown how that pattern applies in
> > WS-Context.
> > Correlation is correlation - it doesn't really matter how you
> > cut it (unless
> > for political reasons).
> 
> I think my words if not easy to parse are logical and not
> self-contradicting. Let me reword it in very concrete terms:
> 
> "WSRF doesn't specify how the messages are correlated" -> "WSRF does
not
> specify what format your correlation header is in"
> 
> "The only thing it specifies is how to create an endpoint reference
that
> indicates how the messages are correlated" -> "the only thing it
> specifies is how to write an endpoint reference, no matter what
> correlation format you use".
> 
> In other words, WSRF does not specify the format used for correlation,
> it specifies the format used for addressing. (But WS-Context specifies
> the format used for correlation).
> 
> You wrote:
> > But you could just remove the ReferenceProperties altogether.
> > You seem to be
> > arguing that WS-R and WS-Context could be used *together*,
> > whereas what I'm
> > saying (and what others have also said) is that WS-Context
> > could be used
> > *instead* of WS-R.
> 
> Yes they could be used together as use of WSRF requires to chose a
> format for correlation header and WS-Context provides such a format.
> 
> WSRF provides a way to expose properties of a resource. WSRF provides
a
> way to group resources. WSRF provides a way to renew references to
> resources. Etc. AFAIK WS-Context does not do that, so I don't see how
> WS-Context could be used instead of WSRF. Remember, the framework is
not
> just the white paper. All the white paper really says that has any
> normative aspect is "use Ws-Addressing for endpoint reference". The
rest
> is just explanations, this is why it's a white paper, not a spec. The
> only overlap I could see is if WS-Context provided an addressing
> mechanism to replace WS-Addressing. I am not aware of such a feature
in
> WS-Context, but I might have missed it.
> 
> As far as removing ReferenceProperties altogether as you suggest, the
> WSRF specs need an addressing mechanism. You might not agree with the
> choice of WS-Addressing for this, but there is a need for something.
> 
> Regards,
> 
> William
> 
> (Savas, your bridging services are very appreciated :-)
> 
> > -----Original Message-----
> > From: Mark Little [mailto:mark.little@arjuna.com]
> > Sent: Sunday, January 25, 2004 12:56 AM
> > To: Vambenepe, William N; Jeffrey Frey; Ian Foster
> > Cc: Newcomer, Eric; ogsi-wg@gridforum.org;
> > owner-ogsi-wg@gridforum.org; Savas Parastatidis;
> > ws-caf@lists.oasis-open.org
> > Subject: Re: [ogsi-wg] RE: [ws-caf] WS-Resource Framework
> >
> >
> > > Hi Mark,
> >
> > Hi William. I think we're still talking about precisely the
> > same thing and
> > as I said in the earlier email it seems like you've got a
> > very restrictive
> > viewpoint for what WS-Context does. If you consider the wider
> > meaning of
> > context (and that's the meaning that WS-Context takes) then
> > they aren't
> > orthogonal at all, and my earlier email illustrates that. (At least
I
> > thought it did.)
> >
> > As I said in that email, whilst it is true that context can be used
to
> > correlate messages sent to individual web services in a
> > "message A should be
> > performed in a way related to message B and C via ctx id X",
> > it's also true
> > that the context can be used in a "message A should be
> > performed related to
> > your prior state X, which by the way so will messages B and C". If
you
> > actually look at the WS-Context spec. and schema you'll see
> > that the context
> > definition itself doesn't have to mention B and C at all (the
> > default one
> > doesn't). It really is up to the recipient of the context
> > (the service) to
> > determine how to use the information in the header. A single service
> > endpoint can multiplex over an arbitrary number of "back-end" state
> > instances using the information within the context. (And this
> > isn't even
> > revisiting the argument of how an application might use the
> > context to group
> > multiple endpoints/states into the same interaction, ensuring
> > consistent
> > state manipulation across all of them for that specific interaction
> > instance).
> >
> > I hate to use the word context in the following sentence because
it'll
> > probably lead to confusion so I'll * it to make sure we
> > understand it's the
> > English term I'm using: the WS-Context information is used to
> > place messages
> > into *context* (circumstance, relation, meaning); it's not
> > limited to what
> > you may be assuming in terms of a security context or
> > transaction context
> > (though even there I showed that there is an exact mapping to
> > the pattern
> > shown in the WS-R document). And this way of using context
> > isn't just a
> > happy coincidence - it's one intended use pattern from the
> > requirements we
> > obtained by talking to Web services vendors and users. So I need to
> > reiterate this point: WS-Context and WS-R are not orthogonal
> > as far as I can
> > see.
> >
> > Now maybe you're argument is that WS-Context is too general?
> > If so, come on
> > over to the OASIS WS-CAF technical committee where we'd love
> > to have your
> > interaction.
> >
> > >
> > > To a large extent WS-Context and WSRF are orthogonal.
> > WS-Context defines
> > > a way to convey, in messages, the fact that some of these
> > messages are
> > > related to one another. WS-Context doesn't care about what
> > this means.
> >
> > I don't understand why you say that WS-Context doesn't care
> > about what the
> > information means. Are you saying that the sender of a WS-R
> > message cares
> > about the endpoint data in a different manner? The sender of
> > a WS-Context
> > enhanced message would do just the same thing. In both
> > instances the sender
> > needs to know a priori that the recipient is the right
> > "instance"; it does
> > this by defining some "meaning information" in the message being
sent;
> > whether that is as additional information in the address
> > (akin to a CORBA
> > object identity asWS-R seems to do) or related to the message
> > (as WS-Context
> > does) is a matter or pattern only, but they both require the
recipient
> > end-point to understand what that information is and how to use it.
> >
> > >  I
> > > agree with you that nothing in WS-Context prevents this
correlation
> > > mechanism to be used to express the fact that the messages are
> > > correlated for the purpose of expressing that their
> > processing should
> > > apply to a specific resource.
> > >
> > > WSRF doesn't specify how the messages are correlated. The
> > only thing it
> > > specifies is how to create an endpoint reference that
> > indicates how the
> > > messages are correlated.
> >
> > This sentence doesn't seem to parse. The reason I'm confused
> > here is you say
> > that WS-R doesn't say how messages are correlated only how
> > the messages are
> > correlated? Do you mean it only provides a means of correlation at
the
> > service? If so, I've also shown how that pattern applies in
> > WS-Context.
> > Correlation is correlation - it doesn't really matter how you
> > cut it (unless
> > for political reasons).
> >
> > > Nothing in WSRF prevents WS-Context headers to
> > > be used for correlation. Quoting from your email:
> > >
> > > > <wsa:EndpointRefrence>
> > > >     <wsa:Address>
> > > >         http://....
> > > >     </wsa:Address>
> > > >     <wsa:ReferenceProperties>
> > > >         <tns:resourceID>C</tns:resourceID>
> > > >     </wsa:ReferenceProperties>
> > > > </wsa:EndpointReference>
> > > >
> > > > the same thing can be achieved using context (in pseudo-code):
> > > >
> > > > <wsctx:context>C</wsctx:context>   <--- appears in the
> > header block
> > > >
> > > > <wsa:Address>
> > > >     http://
> > > > </wsa:Address>
> > >
> > > Nothing prevents tns:resourceID from being wsctx:context in
> > the endpoint
> > > reference:
> > >
> > > <wsa:EndpointReference>
> > >     <wsa:Address>
> > >         http://....
> > >     </wsa:Address>
> > >     <wsa:ReferenceProperties>
> > >         <wsctx:context>C</wsctx:context>
> > >     </wsa:ReferenceProperties>
> > > </wsa:EndpointReference>
> >
> > But you could just remove the ReferenceProperties altogether.
> > You seem to be
> > arguing that WS-R and WS-Context could be used *together*,
> > whereas what I'm
> > saying (and what others have also said) is that WS-Context
> > could be used
> > *instead* of WS-R.
> >
> > >
> > > > The endpoint that receives both message types has to parse
> > > > the message and
> > > > determine the circumstances in which it can be used, i.e., in
> > > > this case the
> > > > state to which it should be applied. The only difference I
> > > > can see is that
> > > > in WS-R, the context for the message is embedded in the
> > > > endpoint reference,
> > > > whereas in WS-Context it's in the header.
> > >
> > > But there is no requirement that the endpoint reference be
> > sent in the
> > > message. According to WS-Addressing, the address
> > information is used by
> > > the sender but what needs to be in the message is the content of
> > > wsa:ReferenceProperties, using the ways specified by the
> > binding. Which,
> > > for SOAP means as a SOAP header. So the message would look like a
> > > perfectly compliant WS-Context message, carrying a
> > WS-Context header.
> >
> > And precisely how is this different from what WS-Context does and
the
> > example I gave? I'm sorry, but you seem to be arguing for the
> > fact that
> > WS-Context can be used here instead.
> >
> > >
> > > WSRF is not about how to correlate messages, it is about providing
> > > useful features (like properties and lifecycle) when
> > message correlation
> > > is used to express access to a resource through a Web service.
> >
> > And context is related to lifecycle and properties. As I said
> > in an email to
> > Ian, I think this is something that can't really be argued
> > from a technical
> > perspective: as far as I can see, there is no reason why
> > WS-Context (or
> > context in general, in the case where the WS-R partners for
> > some reason
> > didn't want to get involved in an open standard aproach like
> > WS-Context)
> > could not have been used here. However, I'm still more than willing
to
> > continue the discussion in case there is something I (or you)
> > have missed
> > that might just be that important element of differentiation.
> >
> > BTW, when we were part of HP Middleware, we worked with IBM
> > on something
> > called the Additional Structuring Mechanisms for the OTS
> > (CORBA based),
> > which could have been used to solve a similar requirement to
> > WS-R but using
> > a pattern more closely aligned to WS-Context & WS-CF. So I
> > don't really
> > believe that this is a technical matter.
> >
> > Thanks for the response,
> >
> > Mark.
> >
> > ----
> > Mark Little,
> > Chief Architect, Transactions,
> > Arjuna Technologies Ltd.
> >
> >
> >
> > >
> > > Regards,
> > >
> > > William
> > >
> > > --
> > > William Vambenepe
> > > Hewlett-Packard
> > >
> > >
> > > > -----Original Message-----
> > > > From: Mark Little [mailto:mark.little@arjuna.com]
> > > > Sent: Saturday, January 24, 2004 3:05 AM
> > > > To: Jeffrey Frey; Ian Foster
> > > > Cc: Newcomer, Eric; ogsi-wg@gridforum.org;
> > > > owner-ogsi-wg@gridforum.org; Savas Parastatidis;
> > > > ws-caf@lists.oasis-open.org
> > > > Subject: Re: [ogsi-wg] RE: [ws-caf] WS-Resource Framework
> > > >
> > > >
> > > > Jeffrey, after having read through the WS-R specifications, I
> > > > fail to see
> > > > any subtle or not-so-subtle distinction. Maybe this is due to
> > > > misundertanding of WS-R on my part, or perhaps a
> > misundertanding of
> > > > WS-Context on yours, but I'd like to explore the
> > perceived mismatch.
> > > >
> > > > Whilst it is true that the types of context to which you
> > > > refer allow for an
> > > > interoperable understanding between client and server, I
> > > > think that misses
> > > > the real point of WS-Context in general: to allow the
unambiguous
> > > > correlation of a set of messages sent to a (set of)
> > endpoints in an
> > > > implementation (or context specific) manner; the endpoint
> > may use that
> > > > context to associate a specific state to itself prior to
> > > > performing any work
> > > > that may be implied by the receipt of those messages.
> > > >
> > > > I think we're agreed that context goes beyond transactions,
> > > > but if you take
> > > > transactions for a second, let's look at the X/Open XA
> > > > specification and
> > > > particularly how a type of context is used within that. Within
XA,
> > > > transactions are identified by XIDs and a given resource manager
> > > > (essentially the entity that controls the way in which data
> > > > is transacted to
> > > > a back-end database) may multiplex across many different
> > transaction
> > > > instances. So, for example, in the C API for XA, there is a
struct
> > > > (xa_switch_t), that has operations for preparing, committing,
> > > > rolling back
> > > > etc. transactions and each of those operations takes an XID
> > > > to identify the
> > > > transaction (state) on which it should operate: only one
> > > > instance of the
> > > > struct exists. So, you could have an XA service that receives
> > > > messages to
> > > > commit (say) a transaction and the context for that message
> > > > would be an XID
> > > > that the service uses to determine which state instance
> > to manipulate.
> > > >
> > > > What I hope I've illustrated is that context isn't just used
> > > > to tie together
> > > > endpoints for interoperability: it can be used to
> > > > unambiguously identify
> > > > stateful instances in precisely the same way that is shown in
> > > > the example
> > > > pattern from the ModelingState (page 12). Or did I miss
something?
> > > >
> > > > In fact, if we look at the schema from that example:
> > > >
> > > > <wsa:EndpointRefrence>
> > > >     <wsa:Address>
> > > >         http://....
> > > >     </wsa:Address>
> > > >     <wsa:ReferenceProperties>
> > > >         <tns:resourceID>C</tns:resourceID>
> > > >     </wsa:ReferenceProperties>
> > > > </wsa:EndpointReference>
> > > >
> > > > the same thing can be achieved using context (in pseudo-code):
> > > >
> > > > <wsctx:context>C</wsctx:context>   <--- appears in the
> > header block
> > > >
> > > > <wsa:Address>
> > > >     http://
> > > > </wsa:Address>
> > > >
> > > > The endpoint that receives both message types has to parse
> > > > the message and
> > > > determine the circumstances in which it can be used, i.e., in
> > > > this case the
> > > > state to which it should be applied. The only difference I
> > > > can see is that
> > > > in WS-R, the context for the message is embedded in the
> > > > endpoint reference,
> > > > whereas in WS-Context it's in the header. But something
> > > > (whether you call it
> > > > an interceptor, XML processor handle, or whatever) has to
> > > > pick apart the
> > > > message.
> > > >
> > > > You say that there's nothing extra needed in terms of a
> > > > handler over and
> > > > above what's already in WS-Addressing, but isn't that
> > just saying that
> > > > because you leverage something that has handlers, you don't
> > > > have to redefine
> > > > them?
> > > >
> > > > And in both cases it can be just as opaque to client and
service.
> > > >
> > > > Although your interpretation of how WS-Context *may* be used
> > > > is certainly
> > > > correct, the fact is that we've seen many different use cases
> > > > for context
> > > > that show the general notion of a context should not be
> > limited to a
> > > > specific use case. Identifying state at an endpoint is
> > possible by a
> > > > correlation id (e.g., a cookie), and in fact state can be
> > > > encoded within a
> > > > context for purely stateless services.
> > > >
> > > > I think as Savas started to elucidate, identification of
> > > > stateful instances
> > > > via context also appears to be a lot easier when you have
> > > > mutliple services
> > > > in the same interaction. With context, the invoker of a set
> > > > of services
> > > > would typically selects the relevant context id that
> > > > represents a specific
> > > > set of stateful services and all of the services see the same
> > > > context id and
> > > > map that to whatever state is appropriate for that
> > > > interaction. It would
> > > > appear from the WS-R documents that in a similar scenario,
> > > > each stateful
> > > > service generates a different resourceID that somehow the
> > > > invoker would need
> > > > to tie together into a collaborative effort. What I mean by
> > > > this is that the
> > > > invoker of those multiple stateful services would need to
> > > > remember each of
> > > > the resourceIDs (or rather their unique EndpointReference).
> > > > That seems like
> > > > a rather heavyweight approach and one which appears to
> > have scaling
> > > > problems.
> > > >
> > > > You also mention that the WS-R "context" is only produced by
> > > > the service,
> > > > rather than by the client in WS-Context. However, that's
> > > > wrong - the context
> > > > does not have to be produced by the client in WS-Context and
> > > > in fact can be
> > > > augmented by each service. So, a "blank" context could be
> > > > received by a
> > > > service that then operates on some state which the client needs
to
> > > > unambiguously identify later, and in which case the service
> > > > can add the
> > > > state identification to the context that flows back to
> > the client (or
> > > > recipient of the response).
> > > >
> > > > It may be that the model outlined in the WS-R documents for
> > > > representing
> > > > stateful instances is more ideal for the Grid environments in
> > > > which it has
> > > > evolved. But in that case, it's worth pointing out that a
> > > > generic notion of
> > > > context can also support that. WS-Context has an explicit
> > > > (though optional)
> > > > context element for identifying the endpoints that are
> > > > participating in an
> > > > interaction.
> > > >
> > > > So, in conclusion, I may be totally off-base here in my
> > > > understanding of the
> > > > WS-R specifications, but I don't see a distinction between
> > > > them and what
> > > > WS-Context is attempting to achieve. If you take a very
> > > > restrictive view of
> > > > what context is, then I can understand why you may think there
are
> > > > differences. However, we haven't taken that restrictive view.
> > > > Maybe its
> > > > approaching the same problem from different ends of the
> > > > spectrum and in
> > > > which case I'd echo Eric's original question about whether
> > > > some level of
> > > > convergence makes sense.
> > > >
> > > > All the best,
> > > >
> > > > Mark.
> > > >
> > > > ----
> > > > Mark Little,
> > > > Chief Architect, Transactions,
> > > > Arjuna Technologies Ltd.
> > > >
> > > > ----- Original Message -----
> > > > From: "Jeffrey Frey" <jafrey@us.ibm.com>
> > > > To: "Ian Foster" <foster@mcs.anl.gov>
> > > > Cc: "Newcomer, Eric" <Eric.Newcomer@iona.com>;
> > > > <ogsi-wg@gridforum.org>;
> > > > <owner-ogsi-wg@gridforum.org>; "Savas Parastatidis"
> > > > <Savas.Parastatidis@newcastle.ac.uk>;
> > <ws-caf@lists.oasis-open.org>
> > > > Sent: Friday, January 23, 2004 6:11 PM
> > > > Subject: Re: [ogsi-wg] RE: [ws-caf] WS-Resource Framework
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > I agree with Ian. There is a subtle but important
> > > > distinction. Context, as
> > > > referred to in WS-Context, is explicitly declared and meant
> > > > to facilitate
> > > > an interoperable understanding between the client and the
> > service. For
> > > > example, a transactional unit of work is something that can
> > > > be established
> > > > by the client and sent to the service in a well known context
that
> > > > accompanies the message to the web service. The same is true
> > > > for contexts
> > > > that represent security function, etc. This is not the same
> > > > as what we have
> > > > introduced with the WS-Resource. There is no need to declare the
> > > > WS-Resource context for interoperability reasons. The
> > > > WS-Resource "context"
> > > > is not produced by the client. It is produced and consumed by
> > > > the service.
> > > > It is carried in the EPR as an opaque construct to the
> > > > client. There is no
> > > > need for the client to interpret or inspect the contents of
> > > > the reference
> > > > properties. In fact, there is no additional "context" handler
> > > > required at
> > > > all on the client side of the interaction other than what
> > is already
> > > > generically specified in the WS-Addressing specification. So,
> > > > while I can
> > > > understand that this appears to be the same at an
> > abstract level of
> > > > understanding, we did not intend the identity of the
> > resource as it is
> > > > treated in the EPR to be interpreted as "context" in the same
> > > > way other
> > > > usage context is produced and consumed across the web service
> > > > interaction
> > > > with the client.
> > > >
> > > > In addition, while we know some have an aversion to the
> > > > treatment of the
> > > > stateful resource as a "first class" addressable entity or as
> > > > the implied
> > > > target of the interaction from the client., some do not. And
> > > > if your view
> > > > is that the resource is the "target" of the message
> > > > interchange from the
> > > > client the service, our view is that it should be treated as
> > > > distinct from
> > > > other execution contexts which exist not for the purpose of
> > > > identifying the
> > > > target of the message exchange, but to provide additional
> > > > control over how
> > > > the target of the message exchange is to be treated.
> > > > WS-Context should be
> > > > used to facilitate the contextual usage of the target of the
> > > > message, not
> > > > the target of the message itself.
> > > >
> > > > Jeffrey Frey
> > > >
> > > > IBM Distinguished Engineer
> > > > OnDemand System Architecture and Design
> > > > Phone: 845-435-3067  Tie: 8-295-3067  Cell: 914-456-6556
> > > > Notes: Jeffrey Frey/Poughkeepsie/IBM@IBMUS
> > > > Internet: jafrey@us.ibm.com
> > > >
> > > >
> > > >
> > > >
> > > > |---------+---------------------------->
> > > > |         |           Ian Foster       |
> > > > |         |           <foster@mcs.anl.g|
> > > > |         |           ov>              |
> > > > |         |           Sent by:         |
> > > > |         |           owner-ogsi-wg@gri|
> > > > |         |           dforum.org       |
> > > > |         |                            |
> > > > |         |                            |
> > > > |         |           01/22/2004 05:34 |
> > > > |         |           PM               |
> > > > |         |                            |
> > > > |---------+---------------------------->
> > > >
> > > > >-------------------------------------------------------------
> > > > --------------
> > > > ---------------------------------------------------------|
> > > >   |
> > > > |
> > > >   |       To:       "Savas Parastatidis"
> > > > <Savas.Parastatidis@newcastle.ac.uk>, "Newcomer, Eric"
> > > > <Eric.Newcomer@iona.com>               |
> > > >   |       cc:       <ws-caf@lists.oasis-open.org>,
> > > > <ogsi-wg@gridforum.org>
> > > > |
> > > >   |       Subject:  Re: [ogsi-wg] RE: [ws-caf]
> > WS-Resource Framework
> > > > |
> > > >   |
> > > >            |
> > > >
> > > > >-------------------------------------------------------------
> > > > --------------
> > > > ---------------------------------------------------------|
> > > >
> > > >
> > > >
> > > >
> > > > Eric:
> > > >
> > > > We (the WSRF authors) are very familiar with WS-Context and
> > > > certainly agree
> > > > that it has an important role to play.
> > > >
> > > > However, we also believe that there are important
> > situations in which
> > > > stateful resources need to be identified and managed as
> > first-class
> > > > entities: thus WS-Resource Framework. Thus the enthusiastic
> > > > response we are
> > > > seeing to the proposal from the IBM and HP Web services
> > > > teams, as well as
> > > > many others.
> > > >
> > > > Ian.
> > > >
> > > > At 10:06 PM 1/22/2004 +0000, Savas Parastatidis wrote:
> > > >
> > > >       Dear Eric,
> > > >
> > > >
> > > >
> > > >       I agree with your comments. In fact, back in August
> > 2003 we used
> > > >       WS-Context as an example of how stateful interactions
and/or
> > > >       distributed units of work could be modelled. This was
> > > > part of our
> > > >       proposals for a WSA-friendly framework for building
> > > > Grid applications
> > > >       (http://www.neresc.ac.uk/ws-gaf).
> > > >
> > > >
> > > >
> > > >       Regards,
> > > >
> > > >       --
> > > >       Savas Parastatidis
> > > >       http://savas.parastatidis.name
> > > >
> > > >
> > > >       From: Newcomer, Eric [mailto:Eric.Newcomer@iona.com]
> > > >       Sent: Thursday, January 22, 2004 6:28 PM
> > > >       To: Mark Little; Savas Parastatidis;
> > ws-caf@lists.oasis-open.org
> > > >       Subject: RE: [ws-caf] WS-Resource Framework
> > > >
> > > >
> > > >
> > > >       I have the general impression of the OGSA specs as the
> > > > equivalence of
> > > >       CORBA.
> > > >
> > > >
> > > >
> > > >       On the topic of the WS-Resource Framework in
> > > > particular, I've looked
> > > >       through the specs and I think WS-Context could have
> > > > been used, and
> > > >       it's unfortunate it wasn't.  I suppose the Resource
> > > > Framework effort
> > > >       grew out of the Grid work however so it has a
> > > > completely independent
> > > >       origin.
> > > >
> > > >
> > > >
> > > >       I also agree that I can't see a practical difference
> > > > between context
> > > >       management in transactions and the context management
> > > > defined for the
> > > >       Resource Framework.
> > > >
> > > >
> > > >
> > > >       It would be nice to try to converge these things at
> > > > some point and in
> > > >       some organization - is that OASIS?
> > > >
> > > >
> > > > _______________________________________________________________
> > > > Ian Foster                    www.mcs.anl.gov/~foster
> > > > Math & Computer Science Div.  Dept of Computer Science
> > > > Argonne National Laboratory   The University of Chicago
> > > > Argonne, IL 60439, U.S.A.     Chicago, IL 60637, U.S.A.
> > > > Tel: 630 252 4619             Fax: 630 252 1997
> > > >         Globus Alliance, www.globus.org
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > >
> >
> >




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