On 03/28/2015 04:42 AM, Dave Cridland wrote:
I agree that urn registration is a pain, and it lacks any domain based ad hoc usage. Both those are bad; Google, for example, use both an unregistered scheme of google, and a urn namespace urn:google. The former they could in principle register; but the latter they couldn't due to the draconian rules.
One of the many things that motivated creation of URNs was to avoid the mess that resulted when DNS names were taken away from their owners, or when resources had to be rehosted elsewhere (say when an organization split or some of its activity moved to another organization), thus invalidating the URLs that had been assigned to those resources. URNs are supposed to be long-term stable names in ways that it's difficult to assure for DNS-based URLs.
At one time people did kick around the notion of combining a DNS name with a date, to avoid that problem. That would allow URNs with that name to continue to be valid, but depending on that the DNS name for resolution would still be problematic. But that still has the potential for thorny trademark-related issues. And there have at various times also been attempts to threaten the uniqueness of DNS names, e.g. by creating alternate DNS roots, so making URNs that relied on DNS names seemed dubious for that reason also. Bottom line: embedding DNS names in URNs seems like a bad idea.
(One thing that handles and DOIs got right, and I wish we had done with URNs, was making their equivalent of "name space identifier" completely devoid of any company name or trademark.)
Keith