RofR

[Paul Harrison]

Tony Linde wrote:
> 
> Going on to Matthew's point, some registries can only search on specific
> extensions, so we'll need to be able to list the schemas supported by those
> registries (default is that all searches are enabled).
> 
> Sound right?
> 

No, for an extensible system you cannot have a default of "All" - you 
need always to list explicitly the things that you support, otherwise 
someone adds a new exension that you do not know about (and do not 
support) and you would still be claiming with the default "All" to 
support it.

It would probably need a list of namespaces that the registry supports 
to make this distinction. However, this also has implications for the 
harvesting - to avoid getting partial records a registry should not 
harvest records with namespaces that it does not understand.

The current situation is problematic

Consider this CEA resource

http://galahad.star.le.ac.uk:8081/astrogrid-registry/viewResourceEntry.jsp?version=0.10&IVORN=ivo://org.astrogrid/JBORealCEC

it has an extension that lists the Applications that the server can run 
- the cea:ApplicationReference elements


This has been harvested into the STSCI registry as

http://nvo.stsci.edu/voregistry/registry.asmx/QueryVOResource?predicate=identifier%3D%27ivo%3a%2f%2forg.astrogrid%2fJBORealCEC%27

i.e. has lost all of the important extension information - it would be 
better not to find the resource at all in the STSCI registry, than to 
gain a false impression of the capabilities of the resource in the CEA case.

Carnivore does contain a correct record - It is just not so easy to 
provide a URL that will point to the record. Search for JBORealCEC in 
the simple search interface.

I think that the only practical course at the moment is to store the 
necessary metadata about registries that describes their differences, 
rather than mandate that all of them are the same. This does not 
preclude a future where all registries are equally capable, but allows 
us to interoperate now.

-- 
Paul Harrison
ESO Garching
www.eso.org