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Re: [Fwd: Re: Approval of initial Dublin Core Interoperabiity Qualifiers]

From: Leslie Daigle <leslie@thinkingcat.com>
Date: Wed, 03 May 2000 21:39:38 -0400
To: W3C URI List <uri@w3.org>
Message-id: <3910D4DA.55CA0880@thinkingcat.com>
Howdy,

Please indulge me as I reply to a bunch of the messages in this
thread in one message -- I had mail failure earlier in the week,
and am just catching up.

Ray Denenberg wrote:
> On the issue "what is a URI?", I see two differing views:
> 
> (a) URI schemes fall into two (or more) broad classes, URL and URN. Each
> URI
> scheme is cast into one or the other class; thus for example "HTTP:"  is
> a
> URL scheme and "hdl:" a URN scheme. (Of course, there are RFCs that
> still
> hypothesize about an additional class, URC.)
> 
> (b) The distinction between URL and URN is artificial, and therefore
> this
> "level" in the URI hierarchy  un-necessary. Thus  "HTTP:" and "hdl:" are
> simply URI schemes. By this view, the concept of "URL" and "URN" would
> go
> away, and be replaced by "URI".  (Which does not mean that any of the
> proposed URN schemes would go away; they would just become URI schemes,
> as
> would HTTP.)

An interesting characterization of current views on the issue; my
personal thought is that, probably as a result of the (in the end)
irreconcilable difference of opinion as to whether one wants/can
have a distinction between addresses and names, the situation
evolved from a) into c), where 

	c) URN is well-defined: there is a URI scheme, URN:, which
	   does aim to fulfill many of the goals laid out in the
	   original URI documentation.  It is not the only
	   scheme that does -- persistence, etc, may well be
	   characteristics sought/provided by others.  

Thus, hdl: is _not_ a URN, although it can be one or both of:

	1. a URI scheme that provides many (perhaps all) of the
	   characteristics originally required for hypothetical URNs,
	   and

	2. a URN: namespace (i.e., carried in URNs).

In my experiences talking with various communities that have
differing needs of identifiers, it has become clear that "applicability"
documents are an issue.  However, I don't think that's in the
purview of the IETF (or probably the W3C, although I'm less familiar
with its scope) to produce -- the IETF can produce a document that,
for example, lays out the types of subdelegation possible for
resolution of URNs, but only repository management specialists,
hardware/software developers, and other interested communities
can determine if the characteristics provided fulfill _their_ 
definitions of persistence, etc.  I'm not entirely sure how to bridge
the gap.

Larry Masinter wrote:
> http://www.w3.org/Addressing/schemes.html looks like some
> notes that someone (Dan Connolly?) keeps in his spare time.
> Probably if we got together we could put it into shape
> in 3-4 hours of joint work.

I really believe this should be a pointer to the IANA registry:

	http://www.isi.edu/in-notes/iana/assignments/url-schemes

It is, after all, their job to keep this up to date.

There will, presently, be a similar page for URN namespaces.

So,

Ray Denenberg wrote:

> I would be happy (or at least happier) if there were a document that
> listed the
> relevant RFCs (and permitted the reader to determine by inference that a
> given RFC
> is  irrelevant, out-of-date, still experimental, etc.) and told you which
> RFC to
> look at to solve a given problem.  But it should be an *authoritative*
> document
> (not just someone's private web page, or some *informal* W3C page).
> 
> And no, it should not be updated for new URI schemes, and yes, it is not
> good to
> try to say "everything" in a single document.

Have a look at the IANA registry, and see what you think is missing.

Personally, I think the data is there, but the information isn't getting
out to the desired audience, presumably (at least in part) because
they aren't familiar with IETF/IANA/W3C documentation & processes.
My concern with this is that I'm not sure they should have to have
this familiarity -- just haven't found the way around it yet.

Leslie.

-- 

-------------------------------------------------------------------
"My body obeys Aristotelian laws of physics."
   -- ThinkingCat

Leslie Daigle
leslie@thinkingcat.com
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Received on Wednesday, 3 May 2000 21:45:54 GMT

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