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Re: [history] Re: name for a resource's URI

From: Hammond, Tony <t.hammond@nature.com>
Date: Mon, 06 Aug 2007 16:21:34 +0100
To: Tim Berners-Lee <timbl@w3.org>, Garret Wilson <garret@globalmentor.com>
CC: Semantic Web <semantic-web@w3.org>
Message-ID: <C2DCFB0E.3B9C%t.hammond@nature.com>

Hi Tim:

Thanks for the <history/> lesson. Much obliged. It was (and is) useful to
review some of these concepts. I do take your basic point about "universal
resource identifiers", albeit with all the baggage that that entails. The
term "universal" is oddly more often than not a limiting term, e.g. UNC -
the Universal Naming Convention as used by Microsoft's (and others')
products. One man's universe is another man's backyard.

I have to say though that I am still not sure what was the point of the
history markup. Was it by way of providing a reason why some occasionally
have recourse to the term "universality"? Hopefully it was not to encourage
the reintroduction of this term.

As far as I can tell the IETF rendered us all an invaluable service by
normalizing the language used in RFC 1630 (1994) whereby "universal resource
identifiers" have offspring "uniform resource locators" (which are then
"still mutating"), and "uniform resource names (then under "debate"). By the
time of RFC 2396 (1998) and its successor RFC 3986 (2005) there is no longer
mention of universality in those documents (apart from the reference to the
earlier document). It also does not appear in the Joint W3C/IETF URI
Planning Interest Group report RFC 3305 (2002).

It certainly seems to me that URI as a "uniform" prescription for generating
"resource identifiers" is a very modest, focused and achievable aim. It does
not attempt to grapple with any larger vision of the "universal" but plays
along nicely towards that same goal.

You say in your post that:

    "The universality of the URI is a fundamental aspect of the web
architecture."

Strangely this fact is not mentioned in AWWW (2004).

You also say that:

    "It remains that the benefit of the web is primarily the wide
interoperability of this single namespace."

I remain a little perplexed as to which namespace you are referring to
(URI?). Here from your recent "Linked Data" article (2006) in the informal
"Design Issue" series, you say:

   "The second rule, to use HTTP URIs, is also widely understood. The only
deviation has been, since the web started, a constant tendency for people to
invent new URI schemes (and sub-schemes within the urn: scheme) such as
LSIDs and handles and XRIs and DOIs and so on, for various reasons.
Typically, these involve not wanting to commit to the established Domain
Name System (DNS) for delegation of authority but to construct something
under separate control. Sometimes it has to do with not understanding that
HTTP URIs are names (not addresses) and that HTTP name lookup is a complex,
powerful and evolving set of standards. This issue discussed at length
elsewhere, and time does not allow us to delve into it here."

    - http://www.w3.org/DesignIssues/LinkedData.html

I may be reading this wrongly but it seems to be disparaging the
introduction of new URI schemes. At least that's how the language speaks to
me ("deviation", "constant tendency", "various reasons", "not wanting to
commit", "not understanding"). And, btw, none of the namespaces you mention
are registered URI schemes. (I should know as co-author of an abortive
"doi:" Internet-Draft. :) You also don't mention the more successful
non-HTTP URI schemes which have been registered and are actively used:
"info:" and "tag:".

This exhortation (to use HTTP identifiers exclusively) is odd also when
considering that creating resource references within the URI namespace can
be an extraordinarily difficult undertaking. I know that the orthodox view
is to follow the classic recipe "First register your domain name, ..."
(apologies to Mrs Beeton), but for "various reasons" this is not always
practicable or preferable, the issues being primarily concerned with
namespace authority and identifier management.
 
As Dame Shirley would surely sing us out it's all "just little bits of
history repeating". ;)

Tony


On 3/8/07 16:31, "Tim Berners-Lee" <timbl@w3.org> wrote:

> <history>
> However, my giving in by dropping the term "Universal" for "Uniform"
> in the IETF arguments,
> while perhaps pragmatic in allowing the URI spec to get through at
> all,  was in other ways
> a big mistake.   The argument against "Universal" was something like
> "You can't have the
> impertinence to say you are developing something universal, which
> will apply to anything".
> In fact I should have retorted that actually (a) the whole point was
> that it *should* be something into
> which *any* system's identifiers can be mapped  and (b) that was not
> impertinent as it passes the Test of Independent Invention
> <http://www.w3.org/DesignIssues/Evolution.html#TOII> as anyone else
> can map my universal system
> into theirs, and one can gateway the two URI spaces.  But I didn't,
> and if I had, who knows, maybe the
> web would have been pushed back on harder by the IETF
> 
> The universality of the URI  is a fundamental aspect of the web
> architecture.
> 
> It remains that the benefit of the web is primarily the wide
> interoperability of this single namespace.
> 
> </history>
> 
> On 2007-08 -02, at 09:25, Garret Wilson wrote:
> 
>> 
>> Right. Thanks. It was a long day. ;)
>> 
>> Garret
>> 
>> Hammond, Tony wrote:
>>>> as URI means "resource identifier" (and a universal one, at that), I
>>>> 
>>> 
>>> Nope. Not universal. URI is *not* a universal identifier. It's a
>>> "uniform"
>>> identifier. Different kettle of fish.
>>> 
>>> Tony
>>> 
>>> 
>>> 

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Received on Monday, 6 August 2007 15:26:36 GMT

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