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Re: FW: New Version Notification for draft-masinter-dated-uri-06

From: Dan Brickley <danbri@danbri.org>
Date: Tue, 14 Jul 2009 09:52:38 +0200
Message-ID: <4A5C3946.3070302@danbri.org>
To: Larry Masinter <masinter@adobe.com>
CC: URI <uri@w3.org>
On 13/7/09 17:59, Larry Masinter wrote:
> After a long hiatus on "tdb", I updated the document
> based on some feedback.
> Changed from URN scheme to URI, got rid of "duri"
> and just left "tdb".

Thanks for keeping this alive!

Side-question: Does it work with 404s? Oddly enough I'm looking for "the 
thing described by" 
http://www.ietf.org/internet-drafts/draft-masinter-dated-uri-05.txt (now 
404'ing per IETF tradition), to remind myself what the "duri" piece did 

The relationship foaf:primaryTopic is, as far as I can see, an 
expression of much the same notion. So a quick compare/contrast here:


At the moment all it says there is

"The foaf:primaryTopic property relates a document to the main thing 
that the document is about.

The foaf:primaryTopic property is functional: for any document it 
applies to, it can have at most one value. This is useful, as it allows 
for data merging. In many cases it may be difficult for third parties to 
determine the primary topic of a document, but in a useful number of 
cases (eg. descriptions of movies, restaurants, politicians, ...) it 
should be reasonably obvious. Documents are very often the most 
authoritative source of information about their own primary topics, 
although this cannot be guaranteed since documents cannot be assumed to 
be accurate, honest etc. "

So wherever we have

	some URI ?x foaf:primaryTopic  some URI ?y,
(and also ?x must be a document of some kind)

	"tbd:"+?x is a URI naming the same thing as URI ?y ...

The tbd: spec allows mailto: URIs to be used to be tdb for people. FOAF 
does this directly using foaf:mbox, or indirectly with 
foaf:mbox_sha1sum, but not using the primaryTopic construct.

Temporal aspects are the other slightly awkward fit between the two 
approaches. In FOAF, all that was left unconstrained. Documents can 
change their primary topic over time. This feels a little too loose, but 
so far nobody's pushed for a more rigid version.

In http://tools.ietf.org/search/draft-masinter-dated-uri-06

    The goal, then, of the "tdb" URI scheme is to provide a mechanism
    which is, at the same time:

       permanent: The identity of the resource identified is not subject
       to reinterpretation over time.

       explicitly bound: The mechanism by which the identified resource
       can be determined is explicitly included in the URI.

Hmm seems you left in some duri pieces?

"Previous versions have couched "tdb" as a URN namespace, and included a 
"duri" scheme for fixing date without indirection, which seems unnecessary."


"2. Syntax
    A tdb URI takes the form:


"   The meaning of a duri is "the resource (or fragment) that was
    identified by the <encoded-URI> (after hex decoding) at the very last
    instant of the date(time) given"."

I'm a bit confused now about what was in tbd vs in duri. How much of the 
date-stamping piece was supposed to be left in?


Received on Tuesday, 14 July 2009 07:53:20 UTC

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