Ah, I take your point. However, it is not about the persistence of the URI qua URI, but rather of the "actionability" (e.g. resolvability) in the sense of the recent GUID report.
There are separate issues about the persistence of the identifier itself. Some organizations permit their employees to use their DNS names for various purposes only during the length of their employment, after which they are required to remove all trace of that use of the name from the internet, whether such removal is technically feasible or not. If I recall correctly, German federal government employees are subject to that requirement. Even when there is no such requirement, I should think that an organization that is the registrant of a DNS name is likely to assert that it owns that name in most legal jurisdictions, and can take whatever legal or technical actions it wishes to control its use. For example, if you produce a URI containing the string creativecommons.org today, even with permission of the owner of that domain name, it is quite possible that said owner, or someone else with one or another ownership of the name "creativecommons.org", might tomorrow be able to enforce on all users of your URI that they stop using it.
On Tue, Sep 1, 2009 at 10:02 AM, Jonathan Reesjar@creativecommons.org wrote:
On Sun, Aug 30, 2009 at 12:29 AM, Bob Morrismorris.bob@gmail.com wrote:
On Fri, Aug 28, 2009 at 11:52 AM, Jonathan Reesjar@creativecommons.org wrote:
... The fact that ICANN and DNS work as well as they do prevents anyone from working on an administratively decentralized alternative.
Umm, I would say that DNS is a giant success story about administratively decentralized technology, but my parsing of this sentence makes me believe that you think it is not administratively decentralized but should be. I suppose only the TLD servers have their DNS records administered of necessity by a single agency, and those provide substantial redundancy.
Sorry I was not clear. Yes, DNS/ICANN is a success story for decentralization. I was not referring to the system as a whole but rather to individual domain names. If the owner of a domain disappears or reorganizes, then all users of its URIs are screwed - the well-known 404 problem. This phenomenon is what I've been calling an "administrative single point of failure" resulting from "administrative centralization", in contrast to "technical single point of failure". No amount of technical replication can address this vulnerability. Just saying that a URI is "persistent" does not make it so, and we know that domains go south in spite of the best intentions of those who originally create and disseminate its URIs, and in spite of the availability of technical replicas (at other locations) of the data that users need.
The only alternative to DNS/ICANN is some alternative to it (sorry) - say, if domain D goes away but a copy of the needed information exists at E, then configure clients somehow to resolve D to E instead of to what ICANN tells you. This is what I've been calling "administrative" redundancy, which has a distinctly different character from mere technical redundancy. My point was just that even though such consumer choice would be wonderful, in principle, and resembles the way that historically robust systems such as the Linnaean system and libraries work (and that would be required in order for many kinds of URN to work), it is a fantasy - it's very unlikely to come about, because DNS/ICANN works so well. (Same argument applies to handle system.) Consumers are left with no power, and putatively-persistent-URI creators, in selfless service to consumers, have to voluntarily take on the burden to just "try very hard" to make domains used in URIs be well-behaved in perpetuity.
Jonathan