Subject: tag URIs and URNs

From: Tim Kindberg <[email-masked]>
Date: Mon, 10 Sep 2001 13:13:10 -0700

I attach draft 01 of a proposal for 'tag' identifiers, from myself and
Sandro Hawke. This replaces the previous 00 draft
(http://www.ietf.org/internet-drafts/draft-kindberg-tag-uri-00.txt).

The chief differences are:

(1) We  have followed Michael Mealling's (and others') suggestion of
appending a request for the 'tag' URN namespace identifier.
(2) We have simplified the date syntax.

As usual, your comments are welcomed.

For more information about tags, please see http://taguri.org.

Tim.

Tim Kindberg

mobile systems and services lab  hewlett-packard laboratories
1501 page mill road, ms 1u-17
palo alto
ca 94304-1126
usa

www.champignon.net/TimKindberg/
[email-masked]
voice +1 650 857 5609
fax +1 650 857 2358

---

From: Martin Duerst <[email-masked]>
Date: Tue, 18 Sep 2001 09:51:21 +0900

It would be very nice if this proposal and Larry Masinter's recent
proposals at draft-masinter-dated-uri-00.txt could be integrated
to avoid unnecessary overlaps.

Regards,   Martin.

---

From: Tim Kindberg <[email-masked]>
Date: Tue, 18 Sep 2001 09:21:34 -0700

>to avoid unnecessary overlaps.

Sandro and I and Larry have exchanged emails about this: we obviously don't
want to create unnecessary overlap. My conclusion is that tags are
fundamentally different from duris, and (I think Lary and Sandro may differ
from me about this) tdbs. I'll quote from the initial exchange over this
and leave it to Larry and Sandro to comment as they feel necessary:

<Excerpt>
TK:
# I've been trying to absorb your 'duri' and 'tdb': URN namespaces work,
# especially in relation to tag URIs, since Sandro Hawke and I were thinking
# of embedding tags into URNs as a special case -- while keeping the
proposal
# of a tag scheme for URIs.

LM:
I've come to the conclusion that your proposal for "tag" and mine
for "duri" and "tdb" are fundamentally different, because you
want a "tag" to be a pure name without any semantics other than
the context of its use, while "duri" and "tdb" have explicit semantics.

TK:
# 'The meaning of a duri is "the resource (or fragment) that was
# identified by the <encoded-URI> (after hex decoding) at the very first
# instant of the date given"'.
# This sounds fundamentally different from our urn:tag proposal (something
of
# the form urn:tag:authority,date:opaque), albeit one based on a similar
# insight of the utility of dating a name. We seek only to provide a way of
# minting identifiers conveniently.

LM:
Yes, I agree, it's fundamentally different.
</Excerpt>

To summarise: my claim would be that tags are essentially human-friendly
UUIDs that are bound to resources by labelling (the authority that mints a
tag is allowed to label one of its resources with the tag) -- and, in
general thereafter, may be bound to resources related to the labelled
resource, as people find it useful to do so. Larry would claim, I believe,
that the denotation of a duri or a tdb is given from their definitions.

All our schemes have in common, at a rather abstract level, is the
technique of dating names (authorities or URIs) to make their denotation
persistent.

Cheers,

Tim.

Tim Kindberg