- 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>
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 >>> >>> >>> ******************************************************************************** DISCLAIMER: This e-mail is confidential and should not be used by anyone who is not the original intended recipient. 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Received on Monday, 6 August 2007 15:26:36 UTC