Thanks very much for the clarifications, Ray.

I personally would find it clearer, cleaner, safer and potentially more 
useful if MODS maintained any generic schema urls at the integral 
version level, and if such generic URLS resolved to the most recent, 
backwards compatible version of the MODS schema within an integral 
version series of MODS schemas.  In other words, I think it would be 
better if the most recent version of the mods schema representing the 
"http://www.loc.gov/mods/v3" target namespace were available at 
"http://www.loc.gov/standards/mods/v3/mods.xsd".  (Offhand I have to 
wonder how mods users are employing the non integral version specific, 
generic mods URL, although I suppose it does provide a shorthand way of 
getting to the most recent schema in an informal context.)

Such a practice would also align with the way the METS Board intends to 
manage the METS schema generic URL--or at least intended the last time 
we discussed the matter.  However, with METS I think we made a very 
short-sighted mistake by not including a version 1 designation in either 
the target namespace URI (http://www.loc.gov/METS/) or the generic URL 
(http://www.loc.gov/standards/mets/mets.xsd) associated with version 1 
of the schema. We are still in Version 1 of METS, but when and if we 
move to a version 2 series of the schema, we will clearly need to add a 
version designation to the target namespace URI for version 2 
(http://www.loc.gov/METS/v2) as well as create a generic, version 2 URL 
(http://www.loc.gov/standards/mets/v2/mets.xsd) that will always yield 
the current METS schema in the version 2 series.

Rick Beaubien

Ray Denenberg, Library of Congress wrote:
> I'll try to address all the points made in this thread.
>
> -  The most current version of MODS will always be maintainted at:
> http://www.loc.gov/standards/mods/mods.xsd
> and in addition will be maintained at a version-specific URL.  Since 
> 3.3 is the most current version, the schemas at the two URLs
> http://www.loc.gov/standards/mods/mods.xsd, and 
> http://www.loc.gov/standards/mods/v3/mods-3-3.xsd are identical 
> (though at different locations).
>
> - "Can  users count on the more generic URL always pointing to the 
> most recent  version of the MODS schema that is backwards compatible 
> through version  3.1?"   No.  Once we go to version 4.0, then the 4.0 
> schema will be at   http://www.loc.gov/standards/mods/mods.xsd.
> We could maintain the most recent 3.x version at 
> http://www.loc.gov/standards/mods/v3/mods.xsd   if that would be 
> useful. So let's say we have a version 3.4, then 3.5, and then 4.0.   
> Then the version 3.5 schema would remain permanenty at 
> http://www.loc.gov/standards/mods/v3/mods.xsd .    Note, we have no 
> plans to do this, but we could if there was a demand for it.
>
> -   "(I believe that there is a break in compatibility between 
> version  3.0 and 3.1)."  No, there was a break in compatibility from 
> version 2 to version 3.0, but not from version 3.0 to version 3.1.
>
> -  "I am asking this because of  its implications for how the 
> schemaLocation in mods instances should be  set up." schemaLocation 
> should never be set to http://www.loc.gov/standards/mods/mods.xsd.   
> If you create a MODS record with the intention that it conforms to 
> version 3.3 (but not necessarily to any higher version), then 
> schemaLocation should  be 
> http://www.loc.gov/standards/mods/v3/mods-3-3.xsd
>
> - On the MODS namespace URI:  when we go to version 4, the namespace 
> URI will change.   It will remain the same for all future 3.x versions.
>
> I've tried to capture all the questions in the thread, let me know if 
> I missed any.
>
> --Ray
>
>
>
> From: "Rick Beaubien" <[log in to unmask]>
>> The current version of MODS is available both through a version 
>> specific URL (http://www.loc.gov/standards/mods/v3/mods-3-3.xsd) as 
>> well as a more generic URL 
>> (http://www.loc.gov/standards/mods/mods.xsd).  Can users count on the 
>> more generic URL always pointing to the most recent version of the 
>> MODS schema that is backwards compatible through version 3.1?  (I 
>> believe that there is a break in compatibility between version 3.0 
>> and 3.1).  Or, to phrase the question a little differently, if a new 
>> version of the MODS schema was produced that was not backwards 
>> compatible with versions 3.1-3.3, would it replace the 3.3 schema 
>> that is now available via the generic URL 
>> http://www.loc.gov/standards/mods/mods.xsd?  I am asking this because 
>> of its implications for how the schemaLocation in mods instances 
>> should be set up.
>>
>> Thanks,
>> Rick Beaubien
>>
>> -- 
>> Rick Beaubien
>> Software Engineer, Research and Development
>> U.C. Berkeley Library
>>
>> Contact information:
>> 505-466-6630
>>
>> 88 Herrada Rd
>> Santa Fe, NM 87508 

-- 
Rick Beaubien
Software Engineer, Research and Development
U.C. Berkeley Library

Contact information:
505-466-6630

88 Herrada Rd
Santa Fe, NM 87508