Some purls might not resolve to URLS any more; however they can still denote.
LCCNs have a specified normal form - see
purl.org URLs, like handles, can generate responses based on prefix matches, so http://purl.org/bibframe/... might only require a singe entry.
It is an open question as to how far generic URLs name, but can usually be ignored by fixing the meaning to be the referent at a specified time in the actual world.
There are also URI schemes that are approximately rigid- the unofficial magnet URI scheme, and the proposed standard in http://tools.ietf.org/html/rfc6920
On 7/18/14, 3:34 PM, Robert Sanderson wrote:
This may be a question for Jeff ... must PURLs re-direct to a non-PURL URL? - If so, then in any case one will need a conformant non-PURL URL for the identifiers.
Or an HTTP space such as Jeff's suggested purl.org.
Taking Ray's example “info:bibframe\publisherNumber\ 256A090” - that could be expressed as "http://bibframe.org/publisherNumber/256A090". I rather doubt that it makes sense to create a PURL for every identifier value, although I like the idea that one could re-direct to a more authoritative URL when the relevant agency actually instantiates a URL form of the identifier scheme.
There's another issue, which is that the "identifiers" in the records today aren't normalized. As Thomas Berger points out, already the LCNA identifier has a different form when encoded in a URL:
MARC: $a n 96055058
I suspect that Ray's publisher number example has been normalized. Some of the schemes are quite awkward in form, using varying punctuation:
074 ##$a277-A-2 (MF)
and sometimes being multi-part, such as:
017 ##$aEU781596$bU.S. Copyright Office 017 ##$aDL 80-0-1524$bBibliothèque nationale du Québec 017 ##$aPA1116341$bU.S. Copyright Office$d20020703
Some of us have the experience of developing search algorithms for these identifiers, but search is considerably different from minting a URI - to begin with, the usage of these in library systems does not require them to be unique; occasionally two normalize to the same string.
What I think we are forgetting here is how we use these various codes and numbers. Essentially they are searched and displayed. In the future we may be using them for linking. This means that if they are "converted" to URLs, they will still need human-readable labels, and some thought must be given to how (if?) they can be made searchable.
-- Karen Coyle [log in to unmask] http://kcoyle.net m: 1-510-435-8234 skype: kcoylenet