SM> Keyword Extension ISSUE 1

SM> Keyword Extension ISSUE 1

SM> Keyword Extension ISSUE 1

TAYLOR,BOB (HP-Vancouver,ex1) robert_b_taylor at hp.com
Mon Sep 30 15:17:09 EDT 2002


See inline - 

bt

> -----Original Message-----
> From: Zehler, Peter [mailto:PZehler at crt.xerox.com]
> Sent: Friday, September 27, 2002 7:15 AM
> To: 'TAYLOR,BOB (HP-Vancouver,ex1)'; PWG Semantic Model WG (E-mail)
> Subject: RE: SM> Keyword Extension ISSUE 1
> 
> 
> Bob,
> 
> A question on C), I am not sure what you mean by well formed. 
>  I assume it
> is not well formed in the XML sense.  My guess is that it is 
> well formed in
> the PWG sense.  That only means that the keyword values used 
> are well-known
> values.  It does not mean that the values are supported by the Printer
> instance.  Is there any requirement for the schema to restrict the
> well-known values to the subset supported by a Printer?

bt: This is probably both in the XML & PWG sense - though much of the
desire I've heard from developers is more from the XML standpoint.  There's
a desire to provide as strong a validation path as possible, since when you
go to XML-oriented data structures you lost much of the compile/link time
error detection you'd get with more explicitly typed interfaces.  The more
we can make our XML structures explicitly declared, the easier it is to
build and deploy reliable solutions.

> 
> I somewhat disagree with D).  I think it is more important to 
> facilitate the
> operational use of the PWG schema in product environments.  
> The well-known
> values in question are not meant for end-user consumption.  
> Facilitating the
> developers can be accomplished through a transformed schema that takes
> appinfo and makes them enumerations.  The client 
> implementation can localize
> or present, in an application specific manner, keywords from 
> appinfo or
> enumeration. 

Agreed - but I believe ease of development feeds into "facilitate the
operation use".  The more we can make this seamless with normal XML
development tools & practices, the easier it will be to get adoption on
both clients & devices.  This isn't "more important" that real industry
use - it helps facilitate it.   I don't think we should be setting these
up as one versus the other - at this point, we should be trying to find
a solution that satisfies both well.

> 
> We have elements that can be vendor or site extended.  
> Whatever we end up
> with I want to insure that Clients are able to discover, via 
> GetAttribute
> action or a schema, and send those extended values.  The 
> Printer must allow
> the application to determine if the attribute/value is supported.

Agreed.

> 
> As for B), I misspoke.  What I intended to say is "Enable print client
> developers to ascertain the supported keywords for an element 
> of a Printer
> at runtime"  I believe the PWG Semantic Model defines the 
> basic objects,
> their attributes, the well-known values for specific 
> attributes and the high
> level description of the actions on the objects.  We have 
> seen in real world
> examples that vendors and site specific extensions and 
> restrictions exist
> and are critical to many customer solutions.  Static 
> definitions may be
> applicable in certain solutions but the majority of solutions 
> require the
> ability to determine what attributes and values are 
> supported.  Capability
> discovery is somewhat related but goes well beyond what 
> attributes/vales are
> implemented by a Printer.  Our goal should be to make the individual
> semantic elements useful for a capabilities solution.

Agreed - this fits my understanding of our scope.

> 
> Pete
> 
> 
> 
> 				Peter Zehler
> 				XEROX
> 				Xerox Architecture Center
> 				Email: PZehler at crt.xerox.com
> 				Voice:    (585) 265-8755
> 				FAX:      (585) 265-8871 
> 				US Mail: Peter Zehler
> 					        Xerox Corp.
> 					        800 Phillips Rd.
> 					        M/S 128-30E
> 					        Webster NY, 14580-9701
> 
> 
> 
> -----Original Message-----
> From: TAYLOR,BOB (HP-Vancouver,ex1) [mailto:robert_b_taylor at hp.com]
> Sent: Thursday, September 26, 2002 4:42 PM
> To: PWG Semantic Model WG (E-mail)
> Subject: RE: SM> Keyword Extension ISSUE 1
> 
> 
> I'd add:
> 
> C)	Allow system entities to use standard XML tools and the PWG (and
> potentially other) schemas to determine that a request is well formed
> D)	Facilitate development around the PWG semantic model by creating
> schema structures that expose both objects and values through 
> commonly used
> development tools
> 
> As for B), I'd say the semantic model certainly needs to 
> enable capabilities
> to be ascertained, but I'm not honestly sure whether it's in 
> scope for the
> SM project to "completely" solve this.  It may be sufficient 
> here just to
> declare the objects & values in such a way that they can be 
> readily used by
> capabilities schemes, and that the "full" capabilities problem will be
> solved in forums like PSI & UPDF.
> 
> bt
> 
> > -----Original Message-----
> > From: Zehler, Peter [mailto:PZehler at crt.xerox.com]
> > Sent: Thursday, September 26, 2002 5:50 AM
> > To: PWG Semantic Model WG (E-mail)
> > Subject: SM> Keyword Extension ISSUE 1
> > 
> > 
> > All,
> > 
> > As stated in the previous mail note "CORRECTED Keyword 
> > Extension Mechanism
> > for schema" sent earlier, I would like to resolve ISSUE 1.
> > 
> > ISSUE 1:  What requirements do we have to help us close on 
> a solution?
> > 
> >  It seems to me that the primary objectives are to 
> > 	A)	Insure that the schema for the print model is easily
> > extended. For both vendors and sites.  The extensions should 
> > be allowed at
> > both the object and semantic element value levels.
> > 	B)	Enable print client developers to ascertain the 
> > capabilities
> > of a print device at runtime.
> > 
> > I think I heard a requirement that a client be able to 
> > determine that a
> > request is well formed, in the PWG schema sense, using XML 
> > tools and the PWG
> > schema.  Am I hearing that requirement correctly?  
> > 
> > What do you think the requirements are for selecting a 
> > solution for schema
> > extensibility?
> > 
> > Pete
> > 
> > 
> > 				Peter Zehler
> > 				XEROX
> > 				Xerox Architecture Center
> > 				Email: PZehler at crt.xerox.com
> > 				Voice:    (585) 265-8755
> > 				FAX:      (585) 265-8871 
> > 				US Mail: Peter Zehler
> > 				        Xerox Corp.
> > 				        800 Phillips Rd.
> > 				        M/S 128-30E
> > 				        Webster NY, 14580-9701
> > 
> > 
> 



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