- From: Larry Masinter <LMM@acm.org>
- Date: Thu, 16 Sep 2004 15:03:25 -0700
- To: "'Stuart Williams'" <skw@hp.com>
- Cc: public-webarch-comments@w3.org
> The direction you offer is largely to dispense with the concept of "URI > ownership" and shift the emphasis toward ownership to resources. Well, I'd like to get away from ownership as much as possible, and shift the emphasis to URI use. But insofar as WebARCH seems to have made a big investment in 'ownership', it's more plausable that resources are owned than URIs (except for URNs, which *are* owned). > I made > a stab at framing "URI Ownership" in terms of the rights and > responsibilities of "URI owners". I have some difficulty accepting > that there is not a sense in which at least some URI are > owned, and its clear that not all resources are own - so we cannot say > generally that it is resource owners that make assignment of a URI as an > identifier of a resource - eg. the planet Mars. I was trying to be careful: resource owners don't make the "assignment" of a URI as an identifier of a resource; in fact, I was also trying to eliminate the verb "assign". The only URIs that get "assigned" are the ones for which assignment is part of the semantics, e.g., URNs. Instead, the meaning of a URI -- to the reciever of a URI -- comes from the URI scheme and its definition. No out-of-band information that isn't directly derivable from the characters of the URI and the definition of the scheme and its delegation should come into play. If you want to cause a URI to mean some resource, so that you can talk to someone else about that resource, you must arrange those resources under your control, as best you can, so that some URI that you can speak identifies the resource that you want to speak about. To talk to you about Mars, I can give some reference indirected through RDF and the "#" mechanism or use 'tdb'. (If we change the question to 'how to speak about Venus', I'll note that Frege had trouble with the morning star and the evening star as two different RIs that might or might not be about the same resource.) I would be happy to dispense entirely with the notion of "ownership", since I think it makes the web architecture messy and adds an unnecessary complexity. I'd be happier to talk about "capabilities" rather than "ownership", and then, just for resources. There are some individuals, groups, or technical (why 'social'?) entities that have the capability to modify resources, and change the behavior seen when resources are contacted or asked for representation. > BTW: I also get vexed with the number of different words that we get > prefixing or post fixing "URI", which are synonymous and > which are not. > > URI Allocation: a transfer of ownership rights over one or more URI to > some social entity (which can include scheme specifications) - an act of > delegation in URI space. I'm certainly not happy with this formulation, since I believe what actually happens here doesn't have much to do with "ownership rights" and more to do with "capability to modify resources identified by one or more URIs" > Is there not some entity that obtains a right to make an association > between a given URI and a resource? No, not in general. "data:,12" means what it means. No entity has any right to associate that with Mars. "http://a.b.c/d/e/f" means, to a receiver, the resource you get when you open a HTTP connection to a.b.c and talk about "/d/e/f" to it. No entity has a 'right' to 'make an association' between that resource and the planet Mars. Perhaps, the domain admin for c can allocate to the domain admin for b.c to the sys admin to a.b.c to the owner of directory /d to the owner of /d/e to actually modify the resource that's associated with /d/e/f, but these acts aren't "make an association between a given URI and a resource", but rather "arrange resources such that the URIs which identifies that resource reaches a resource that can be used as a proxy for Mars". > Such rights may come to them through some delegation chain rooted > in the URI spec. and the IANA scheme registry. Wrong end of the telescope. Neither the URI spec and the IANA scheme registry give anyone any rights. All they do is tell someone who gets a URI how they might interpret the URI. If there are any 'rights' (or, better, capabilities), it is all on the side of resource owners. > It's also not clear that all resources have owners. If resources is > scoped so large as to includes say planets or galaxies, I'm not sure I'd > be able to attribute any particilar owner to say the planet Mars - > though I guess some may stake a claim :-). However, I may have rights in > some sense to associate the URI http://example.org/planets/Mars or > http://example.org/planets#Mars with the planet Mars in such > away that one or both of those URI are said to identify (in a > denotational sense) the planet Mars. No, only in the sense of the indirect references. http://example.org/planets/Mars already has a clear definition, it is the resource that you get when you open a HTTP connection to "example.org" and talk about "/planet/Mars". Any association this has with the actual planet Mars is a matter of association or imagination or interpretation of that resource itself. > I might then want to back this up by making available representations of > the planet Mars to anyone who happens to dereference one or both of > those URI. Of itself that exposes another conuderum... by deploying > representations have I : > 1) magically turned Mars (which I do not own) into an > information resources. This trick doesn't work. Mars is Mars. You can't manipulate Mars. > 2) deployed a new information resource (which I do own) that > then stands proxy for the planet Mars, and gives me the grief that I may want to > speak independently of the proxy and the planet. You have this grief. It is one of the fundamental problems of language: you can never get to Mars, but only to its proxies. "tdb" might give you a hope of speaking independently of the proxy and the planet. > 3) been entirely misguided and the URI (either of then) never > identified the planet Mars in the first place. Yes, indeed. > Anyway... would you claim any rights over the URI based on the DNS name > "larry.masinter.net" (not the resources they identify, but the URI > themselves) ? I don't think the personal reference changes my opinion, even if I wanted to maximize my personal rights. I can't suddenly say "by http://larry.masinter.net I don't mean "the resource you get when you open a HTTP connection to 'larry.masinter.net' and talk about '/'". The URI means what it means, I have no control over that meaning, only over behavior. > ># Many URI schemes are used to described resources > > > > > > ^^^^^^^^^ > URI schemes "describe" resources? Maybe - "describe" doesn't > feel like the right verb. You're right. 'identify' is the best verb to use to describe what Uniform Resource Identifiers do to Resources. > >This gets rid of the notion that the social entity > >owns the URIs: it owns the resources, which makes > >more sense. > > > > > I can't see that it is necessarily the case that all resources have > owners, and I'd be willing to concede that not all URI have owners. > However, I think that, socially, we vest ownership of the URI > space in the IANA registry and the social process (es) that result in the > inclusion of scheme specifcations in that registry. Wrong end of telescope. There is no ownership needed. The IANA registry just tells users how to interpret URIs, and the social process is that writers (those who toss around URIs) can assume that readers (those who get URIs and want to know what Rs they I) agree about what the IANA registry says. > In a sense, when a scheme is registered, ownership of that chunk of a URI space > passes to the registered scheme specification (and the community that maintains > it)... and the scheme specification itself my further delegate ownership > to other registry/specification combinations (eg. URN namespaces) and/or > organisations, roles within the organisation and so-forth. Wrong end of telescope. When a scheme is registered, it lets recievers of URIs know how they should interpret URIs that start with that scheme. No ownership is given to anyone. > >I think it's possible to eliminate "URI ownership" > >in the rest of the document fairly easily. > > > > > You used the word "use" above with respect to URI has a very > egalitarian > feel to it in the sense of there being no primacy of use. I don't mean to be egalitarian, I mean that the power is with the readers, the interpreters, the utterers, those who are involved in a communication about resources and want to use URIs to identify the resources they're talking about. > That seems to me to work as far as a "USE" of a URI is it's occurence in > representations or as a protocol element or written on a > piece of paper. > > But "USE" does not establish who/what gets to form an association > between a URI and the resource it identifies (either > operationally [*] or denotationally [#]). Well, again, you're stuck in 'assign' land, where you think that someone "gets to form an association". But I believe that it is a better model that the association is intrinsic in the definition (except, again, in the special case of URNs where meaning *does* get assigned.) > [*] operationally in the sense of following the documented mechanisms > for dereferencing URI - which I believe is the way you use the word > identify. > [#] denotationally in the sense of folks using URI to name > things in the world (like planets) - which I believe is also a way in which > the word idenify is used. Yes, I accept both modes of identification. > When a URI identifies what it is used to denote then > there appears to be a level of harmony (modulo some discussion of > whether its denotation is an information resource/hypertext > dispenser or the thing that described or depicted by that information resource). Just because you can think of URI identification both operationally and denotationally doesn't mean that the resources identified are different. In order to do most kinds of denotation (like to talk about the planet Mars), you need some kind of implicit or explicit indirection. > ># The owner of a resource may arrange the resources > ># such that a URI can be used to obtain representations > ># of the resource identified by the URI. For example, when > ># a resource owner offers the HTTP protocol ... > ># ... on behalf of the resource owner to provide ... > > > > > Can you explain how this would work for the planet Mars? Only through indirection. In fact, it's unnecessary to arrange any resources: I can use urn:tdb::data,the%20planet%20Mars to talk to you about the planet Mars. No ownership required, either of URIs or of resources. Or I can use http://larry.masinter.net/phrases.rdf#the%20planet%20Mars and arrange some resources: create a file phrases.rdf with a 'the planet Mars' label in it, and 'arrange the resources' by sticking the file on the server that servers http://larry.masinter.net (Thanks to John Masinter, who offered free web hosting to anyone named 'Masinter'). > >>A URI owner SHOULD NOT associate arbitrarily different URIs > with the same resource. > > > >I think this makes little sense as stated, and is > >much more effective changing 'URI owner' to 'resource owner'. > > > > > I think this makes it a little difficult to associate a URI with a > resource like the planet Mars (that may be deliberate). Well, I don't really like the result all that much. How about # Users SHOULD NOT use arbitrarily different URIs for the # same URI. Larry -- http://larry.masinter.net
Received on Thursday, 16 September 2004 22:03:48 UTC