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Cool URIs don't change? Was Re: Perisistence

From: Henry S. Thompson <ht@inf.ed.ac.uk>
Date: Mon, 15 Sep 2008 19:38:03 +0100
To: John Bradley <john.bradley@wingaa.com>
Cc: "Williams, Stuart (HP Labs, Bristol)" <skw@hp.com>, Mark Baker <distobj@acm.org>, "www-tag@w3.org" <www-tag@w3.org>
Message-ID: <f5by71t8dbo.fsf_-_@hildegard.inf.ed.ac.uk>

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I've been re-reading this tangled thread, and want to pull out one
tiny bit to test my understanding:

John Bradley wrote:

> If =skw is assigned to you along with =!BF81.FD97.C81B.B4E5 and at
> some point you stop paying for =skw and TBL wants to purchase it he
> can get =skw but not =!BF81.FD97.C81B.B4E5,  a new CID would be
> created if he needed it.

Would I be correct in saying that it's because you feel obliged to
acknowledge that the injunction "Cool URIs don't change" is
unrealistic, indeed that it you allow naming authorities to recycle names
under their control, e.g. after non-payment of annual rental fees,
that the corresponding URIs _will_ change, that you then need to
make a distinction between what you call persistent vs. non-persistent
URIs?  That is, a ! is the way a naming authority indicates that it
will _not_ recycle a name.

Would I furthermore be correct in concluding that it follows that if a
naming authority leases a _persistent_ name to someone, and they stop
paying, that all the naming authority is committed to doing is
retiring the name and never re-issuing it?  It continues to identify
what it always did, in principle at least, although in practice it may
not (will definitely not?) be possible to retrieve either metadata or
representations using it.

And that the guarantee that a persistent name always identifies the
same resource depends on the good behaviour of the leasee of that
name?

And finally, that persistence does _not_ imply continuity of
ownership?  That is, I may lease a persistent name from some naming
authority, and then sell that name on to someone else.  It's then up
to _their_ good behaviour to continue to use that name to identify the
same resource.

Thanks,

ht
- -- 
       Henry S. Thompson, School of Informatics, University of Edinburgh
                         Half-time member of W3C Team
      10 Crichton Street, Edinburgh EH8 9AB, SCOTLAND -- (44) 131 650-4440
                Fax: (44) 131 651-1426, e-mail: ht@inf.ed.ac.uk
                       URL: http://www.ltg.ed.ac.uk/~ht/
[mail really from me _always_ has this .sig -- mail without it is forged spam]
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Received on Monday, 15 September 2008 18:38:51 GMT

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