Mistakes in registry

[Ray Plante]

Hi Nausicaa and Jean-Christophe,

I took me a couple of messages to surmise your entry point into the 
registry.  Note that the NVO on-line publishing forms for our registries 
have embedded links to the definitions of the terms.  (Perhaps you saw 
this).  

On Fri, 3 Feb 2006, Nausicaa Delmotte wrote:
> I'm having some difficulties as well to understand the difference 
> between Type and resourceType. 

The vanilla "type" metadatum is part of the core resource metadata.  It 
allows a publisher to specify some general categories that the resource 
falls into.  This is especially helpful when the resource does not fit 
into one of the specialized resource classes that have been defined.  

For the other kind of type (we don't call it a "resourceType" any more), a 
resource class is a special extension of the core resource metadata that 
focus on an important subclass of resource--those you pick from up front 
when publishing (organisation, SimpleImageAccess, etc.)  By picking one of 
these, you add extra metadata to the record that describes that 
specialized class of resource.  

> Hence my questions:
> - Has the second list been defined somewhere and is it user-extensible? 
> What is its exact definition? 

The definitions are currently held in the schemas referred to earlier.  
Human-oriented documents for these extensions are primarily in the works 
(although there are docs for SIA and ConeSearch).  

It is not intended that the list be extensible by publishers normally.  
These standard metadata are for interoperability; this implies that others 
must support your extensions.  However, if you and a few of your friends 
at other sites wish to create an extension that you agree on, this is--in 
principle--allowed.  I'll note, however, that if you publish a resource 
record with your own non-standard (in the IVOA sense) extension, there is 
no guarantee that any other registry will take the record.  This may 
change in the future.  

> - There is a kind of overlap between the two lists: see for instance 
> keywords organisation, registry. 
> Is it intended or are the two lists supposed to be merged in the future?

There has been some expectation that some consistancy be maintained 
between the 2 kinds of "types", but I can see how this is confusing.  We 
should have a look at this question.  

> A service is a resource but a resource is not necessary a service, right?

right.

hope this helps,
Ray