R(S)M v0.8

[Ray Plante]

Hey Patricio,

> {Resource Metadata Concepts} -> {Identity Metadata}
> 
> Three elements are listed:
> Title
> ShortName
> Identifier (URI)
> 
> my concern goes to mirrored data. What happens with catalogs located in
> several places? Title and shortName are the same, Will the URI be enough to
> identify these resources as the same? Do we have a mechanism to reliably
> compare two resources and decide that they are the same resource, only
> located in a different location or available through different services
> (DBMSs)?

Short answer: no.

Here's a little more info on where the state of the discussion on mirrors.  
Much of it has been in the context of identifiers.  The bottom line is 
that there is no agreed (or even proposed) framework for handling mirrors 
as of yet.  Nevertheless, we have been discussing it.  

  1)  It is not intended that Title & ShortName be guaranteed to be 
      unique; however, providers are strongly encouraged choose these such 
      that a human can readily distinguish between distinct resources.  
      It is possible (as you say) that mirrored resources may share the 
      same Title or ShortName.  

  2)  Every resource in a registry has a unique identifier.  Even if two 
      resources can logically be considered mirrors they still have 
      different identifiers.  This is because
        a)  we don't have a clear-cut way of defining when two resources, 
            separately accessible, are equivalent.
        b)  we still need a way of distinguishing different instances of a 
            mirrored resource.

  3)  Determining whether two resources are mirrors will be done on the 
      basis of (yet-to-be-defined) metadata specific for this purpose.

  4)  It is expected that URN-like functionality (location- or curation-
      independent identifiers), which addresses both mirrored and moved 
      resources will be built on top of the standards for identifiers and 
      registries. 

cheers,
Ray