Persistent Identifiers: Irony of Fate or just absurd?

24. August 2007 um 01:20 4 Kommentare

The report „Implementing Persistent Identifiers: overview of concepts, guidelines and recommendations“ shows you the impracticality of URN and URN:NBN – you do not even have to read any of the 70 report’s pages to find out: If you try the „persistent identifier“ to get the report’s PDF, you get the following message by a resolver at

Unfortunately the URL could not be resolved. None of the underlying local document resolver were able to find a document with the given identifier. Maybe one of the services is down or a document with the number doesn’t exist. As your URL should contain a persistent identifier, please check again later.

I’d call this 404 2.0! Furthermore at one of the report’s publisher (CERL) points out to a review of the report at – which gives you the current issue of CLIR issues (printed version’s ISSN 1098-6383 is not mentioned anywhere) instead of If you ask Google for the title you easily find the PDF. If you ask WorldCat for the ISBN 90-6984-508-3 you get a record where you have to click and search a lot to guess which link will bring you to the PDF – but it’s only the unresolvable URN again.

If people are already to dump to use existing identifier systems (URL, ISBN, ISSN) in the right way, I strongly doubt that persistent identifier systems will solve any problem.


RSS feed for comments on this post. TrackBack URI

  1. Yep, there are numerous copies on the web (hm, the LOCKSS approach really got something to it). The main server is currently down, so the resolving service is correct in that regard. It will probably be back during the course of this day — I least I hope our staff will sort it out soon. This is something that isn’t dependent on identification, it’s about backups and HA. And short term reaction to outages. I’m somewhat pissed, too. I’ll write a follow-up on this comment when the access is OK again, combined with some reasoning about identifiers…

    Comment by Hans-Werner — 24. August 2007 #

  2. Looks like it works again. The equivalence would be a DNS server breakdown – but DNS is much more stable then any URN-resolving. So with URN you get persistence at the expense of stability.

    Comment by jakob — 27. August 2007 #

  3. It works since 24th of August, ~15:30 CEST. I did just not get to write a follow-up here, since I’m still waiting for some spare time to make some concise arguments on the misconception about what exactly the word „persistent“ in „persistent identifier“ means. It is _not_ resolvability but merely the connection between identified object and its identifier that is persistent. You pretty much covered that in your last sentence: With URNs, persistence comes at the price of (access) stability. This is always conceptually true for any system that relies on indirection for accesses.

    BTW: URNs are not necessarily worser in this regard than domain name based URLs. There are technical means (DDDS) to facilitate URN resolving by means of DNS entries. This, however, seems to be a too complex approach for the moment when end-users are far from even grasping what a URN is (except that it looks like a URL-thingy but nevertheless doesn’t work in the browsers addressbar) and administration doesn’t really know why persistent identification is important anyway (except for getting some certificates for „trusted“ servers).

    Comment by Hans-Werner — 28. August 2007 #

  4. You are right: URNs are not necessarily worser then domain name based URLs. But they are also not necessarily better. Persistence is only a social contract no matter what technique you use. For instance ISBN and ISSN are widely used persistent identifier systems. In some cases publishers break persistence by reusing them – this can happen in the same way with URL, URN, or any other system. You should better propagate URN as „ISBN for electronic documents“ instead of comparing it with URL and technical systems that you cannot rely on anyhow. By the way Google is also a resolver for many kinds of identifiers: Search for urn:nbn:de:gbv:7-isbn-90-6984-508-3-8 t and you get the PDF, reviews, citations, tagging data, an impression of the impact (44 hits at the moment) and much more very useful information!

    Comment by jakob — 29. August 2007 #

Sorry, the comment form is closed at this time.