resource identifiers

[Ray Plante]

Hi Tony,

On Wed, 28 May 2003, Tony Linde wrote:
> I think that at heart I am really uncomfortable with having the ResourceID
> including a component that never gets used in the registry.

...

> <SiaImageID>
>   <ResourceID>
>     <AuthorityID>www.ncsa.uiuc.edu</AuthorityID>
>     <ResourceKey>ADIL/SIA/targeted</ResourceKey>
>   </ResourceID>
>   <ImageKey>95.DR.01.01.fits</ImageKey>
> </SiaImageID>

As I've said, this breaks uniformity for refering to parts.  This also
means we cannot allow a "#..." corresponding to a RecordKey in the URI
form since it cannot be unambigously converted back to the XML form.  (I
don't think the URI form can be effectively extended later because
non-supporters of <SiaImageID> won't know what to do with it.)

If <RecordKey> cannot be part of the <ResourceID>, then I think the only 
solution is to drop Req. (4).

> The ResourceID should be used solely to describe a resource registered
> within the VO and this requires only the AuthorityID and the ResourceKey. 

I guess I'm not grasping why.  I've argued that the RecordKey does not
break the model of an identifier (it is fundementally the same problem, I
think), and it incurs minimal cost to consumers.  The benefit is that we
have a uniform solution of identifying parts that will surely be useful
beyond SIA.

I appreciate your desire to keep the role of IDs "lean and mean", which is 
why I think its good to frame this in terms of requirements.  

cheers,
Ray