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If we find a need to change the XLink schema  (not necessarily for the issue
at hand, but for any reason) and it is a change that would require an
associated change to schemas that use the XLink schema (which is the case
for the issue at hand), then I think we would NOT try to coordinate the
change for all of those schemas. Rather, if for example the change is for a
MODS issue, we would create a separate XLink schema for MODS, change the
MODS schema, and all other schemas would be unaffected.  Then, each of those
schemas could independently do the same thing (create temporary separate
XLink schemas and change the base schema) at their own pace. Once they have
all done that  - if indeed they all choose to do so - then we could make the
change to the original schema and they could all go back to using it, and
all discard the temporary schemas, agains each at their own pace. 

However the latter part assumes (1) that all agree to the change, and (2)
that every schema that uses the LC XLink schema has been identified. (I was
not aware, for example, of the ALTO schema usage. For that matter I did not
even realize that EAD uses it.)

So as I said earlier I am not yet convinced that there is any need for a
change, but if there is, we would use this local approach rather than try to
coordinate a change among multiple schemas. 

--Ray


> -----Original Message-----
> From: Metadata Object Description Schema List
> [mailto:[log in to unmask]] On Behalf Of Redding, Clayton
> Sent: Wednesday, October 12, 2011 2:40 PM
> To: [log in to unmask]
> Subject: Re: [MODS] xlink namespace in MODS schema
> 
> It is also used within the ALTO schema.
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Clay Redding
> Digital Projects Coordinator
> Network Development & MARC Standards Office Library of Congress
> 101 Independence Ave. SE
> Mail Stop 4402
> Washington, DC 20540
> [log in to unmask]
> Voice: (202)707-7196
> Fax: (202)707-0115
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ________________________________________
> From: Metadata Object Description Schema List [[log in to unmask]]
> On Behalf Of Daniel Pitti [[log in to unmask]]
> Sent: Wednesday, October 12, 2011 1:57 PM
> To: [log in to unmask]
> Subject: Re: [MODS] xlink namespace in MODS schema
> 
> It is also used by EAD and EAC-CPF, and so both of these schemas would
> also need to be adjusted. I have copied the various committee chairs
> that need to address this.
> 
> Daniel Pitti
> 
> On Oct 12, 2011, at 10:04 AM, Ray Denenberg, Library of Congress wrote:
> 
> >> From: Jens Østergaard Petersen
> >>
> >> Your document validates with me as well, because the MODS schema
> >> references the XLink schema at
> >> <http://www.loc.gov/standards/xlink/xlink.xsd>.
> >>
> >> My point was that the Library of Congress XLink schema does not
> >> accord with the W3C XLink schema in the naming of
> >> simpleLink/simpleAttrs, so if you change the schemaLocation for the
> >> XLink schema in the MODS schema and substitute it with a reference
> to
> >> the standard XLink schema at <http://www.w3.org/1999/xlink.xsd>,
> your
> >> document becomes invalid.
> >
> > Ok, thanks, I see the problem now (no need to explore Oxygen, etc.
> any
> > further).
> >
> > line 33 of the LC XLink schema says:
> > <attributeGroup name="simpleLink">
> >
> > which corresponds to line 111 of the W3C XLink schema which says:
> > <attributeGroup name="simpleAttrs">
> >
> > And so with the mismatch of names, "simpleLink" vs. "simpleAttrs", if
> > you try to substitute the W3C schema reference in the MODS schema,
> the
> > MODS schema itself won't validate (I tried it) because the schema
> > itself references "simpleLink".
> >
> > This is an easy problem to fix and the fix would be completely
> > transparent.
> > We could make the change in the LC XLink schema, and change the
> > references in the MODS schema, and there would be no need for any
> > changes to MODS instance.
> >
> > Well, It isn't quite that simple. (But almost.) The LC XLink schema
> is
> > used not only by MODS, but also by METS. So unless we coordinated
> this
> > change with the METS folks, we would also need to have separate XLink
> > schemas (a "MODS XLink schema" and a "METS XLink schema") and change
> > the reference in
> > the MODS schema to point to the MODS XLink schema.   Also a trivial
> > change.
> >
> > But I am not sure why this change is warranted.  What is the need to
> > reference the w3c XLink schema rather than the LC schema?
> > If there is a need to do this, we can make theses changes.
> >
> > --Ray=