PubDIDs (and DIDs in general, maybe)

Accomazzi, Alberto aaccomazzi at cfa.harvard.edu
Thu Jan 16 16:54:10 PST 2014


At the danger of stating the obvious: we all know that Norman speaks the
truth.

Thanks for catching my URN vs. URI mangling -- I admit I hadn't looked up
the definition of either one in quite a while.  But despite the misusage of
terms, my point was that the ADS persistent ids were not born as IVORNs for
both practical and political reasons, and I don't think it's worth
agonizing about whether or not they can/should be retrofitted into that
scheme now.  However, if agonize we must, one way out of this IMHO is to
simply say the following:

1. the resource persistent identifier is: ADS/Sa.CXO#obs/05285
2. its corresponding IVO URI is: ivo://ADS/Sa.CXO%23obs/05285
3. its actionable URL is (as of today):
http://vo.ads.harvard.edu/dv/DataResolver.cgi?ADS%2FSa.CXO%23obs%2F05285

i.e. there is a URL-encoding step in going from the identifier to the URIs.
 Doesn't look as pretty as we might have wanted, but it works.

As far as managing these identifiers, let me add a pointer to the EZID
system that CDL uses for its datacite DOIs and arks: http://n2t.net/ezid/
The resolver and registry that they maintain could easily support the ivo
URI scheme if we wanted to, but again no need to go that route unless we
need it for something that plain http doesn't already provide.

Cheers,
-- Alberto



On Thu, Jan 16, 2014 at 1:46 PM, Norman Gray <norman at astro.gla.ac.uk> wrote:

>
> Alberto and all, hello.
>
> On 2014 Jan 16, at 15:14, Accomazzi, Alberto <aaccomazzi at cfa.harvard.edu>
> wrote:
>
> +1 generally, but...
>
> > I think a better way to keep this straight is to think of the "ADS"
> identifiers as URNs and the ivo identifiers as URIs.
>
> Unleashing my inner lawyer: recall that URNs are (according to RFC 2396)
> merely one of the two types of URIs, namely "the subset of URI that are
> required to remain globally unique and persistent even when the resource
> ceases to exist or becomes unavailable."
>
> RFC 3968 <https://www.ietf.org/rfc/rfc3986.txt> mentions that '[a] URI
> can be further classified as a locator, a name, or both', and that '[t]he
> term "Uniform Resource Name" (URN) has been used historically to refer to
> both URIs under the "urn" scheme', but that 'Future specifications and
> related documentation should use the general term "URI" rather than the
> more restrictive terms "URL" and "URN".'
>
> All that said...
>
> > 6. Having said all of this, I still do have one basic question about the
> ivo identifiers that you want to use in datalink, based on my current
> understanding of them.  Specifically, given that these lack persistence and
> multiple resolution features, why bother at all rather than using a plain
> http uris?  I think this question is worth considering now since the
> experience with the dataset ids has taught me that unless there are
> compelling reason to go with a discipline-specific, custom solution you may
> be better off using what the web already gives you for free: namely http
> and dns.
>
> I think this is a really important point, which isn't made often enough
> (cue hobbyhorse).  Without _necessarily_ discounting the existence of such
> 'compelling reasons', non-standard schemes do come with a cost, and they're
> not magic, so that if your resolution mechanism disappears, a URN-named
> object is just as lost, and just as nameless, as one named with a 404ed
> HTTP URI.
>
> I remember a workshop on persistent identifiers of a few years ago, where
> Stuart Weibel (I think; or it may have been John Kunze) made this point
> very convincingly.  Something under purl.org or under id.loc.gov has an
> "institutional commitment to persistence" which is worth an awful lot more
> than any amount of indirection that you get through a fancy URI scheme.  As
> Stuart (or whoever) said , "loc.gov isn't going away any time soon".
>
> DOIs do, I think, have a pretty compelling reason to be a special URI
> scheme, but the thing that's key about DOIs is not the scheme, or the
> Handle-based lookup mechanism, but precisely the "institutional commitment
> to persistence" that they represent.
>
> I don't plan to reopen any discussion here about IVORNs -- fear not,
> everyone -- but will simply note that, on general principles, obsessing
> about the punctuation of URIs is probably a distant second in importance to
> developing and planning these sorts of institutional commitments within the
> IVOA.
>
> All the best,
>
> Norman
>
>
> --
> Norman Gray  :  http://nxg.me.uk
> SUPA School of Physics and Astronomy, University of Glasgow, UK
>
>


-- 
Dr. Alberto Accomazzi
Program Manager
NASA Astrophysics Data System - http://ads.harvard.edu
Harvard-Smithsonian Center for Astrophysics - http://www.cfa.harvard.edu
60 Garden St, MS 83, Cambridge, MA 02138, USA
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