- From: Sandro Hawke <sandro@w3.org>
- Date: Fri, 27 Apr 2001 21:07:45 -0400
- To: michaelm@netsol.com
- cc: "Roy T. Fielding" <fielding@eBuilt.com>, Tim Kindberg <timothy@hpl.hp.com>, uri@w3.org
Thanks for all your thoughtful comments, Michael. One thing I want to ask about before hopping on a plane to WWW10: > > There are lots of "arbitrary" URIs not using URN syntax, like > > "mid:" and "data:". Are those historical anomolies, which really > > should have been URNs? > > For those of us who use URNs, probably. But we're not going to make > a huge stink about it. They're all URIs and thus exist in the same > 'layer' of the web and have the same very basic semantics. ... > URNs do more than that. Infrastructure and systems are being deployed > now that provide all sorts of things for URNs (and URIs in general). > For example, we're setting up a URN based service called a Personal > Internet Name which is a permanent name for a individual or organization. > The ISBN organization is in the process of registering a URN for > all ISBN numbers... ... > And that's why we have URNs. Its a framework within which you can > define your own namespace but which defines a more specific set of > semantics (persistence, location independence, etc) than URIs in the general > case. What's the advantage of having URNs be syntactically distinct from non-URN URIs? It made sense in the days when more people thought URLs and URNs were really different beasts, but now that we seem to understand differently -- as you say the infrastructure really applies to URIs in general -- who (which peice of software) needs to know if a particular URI has URN semantics. I'm fine with "tag:" being a URN scheme if I see some practical use for those extra four characters. Or... Hmm. I don't want tags to have ANY semantics. You're saying URNs are presistent and location independent -- that urn:x always denotes the same object regardless of the time and place of interpretation, right? Hrm. What if we want a term (tag:sandro@w3.org/1-4-27/you) which, when used in a message, denotes the recipient of the message. The term denotes a different recipient if the same message is transmitted again, to someone else. That can be a tag URI. Can it be a URN? (There's a weirdness here between denoting the recipient and denoting the concept of denoting the recipient. I'm trying to do the former; URNs could clearly do the latter, which might be sufficient for all applications.) -- sandro
Received on Friday, 27 April 2001 21:10:04 UTC