Page History

For Identifiers (just the complete URI and local part, not about mechanisms)

	HDL	PURL	PURLz	HNRS	DOI
permanent	?	?	?	?	Yes	Yes ?
permanently resolve to a digital object	Yes ?	?	?	?	?	Yes
unique within our PID system without the DNS name portion of the	?	?	?	?	?	Yes; very flexible naming, including pseudo/paths	Yes, but
URL	?	?	?	?	?	Yes
works with VIVO, arXiv, OAIS (CUL), Voyager Catalog, and WorldCat etc.	?	?	?	?	?	Yes	does nothing in and of itself to not work with existing systems;
resolvable through a web browser	?	?	?	?	?	Yes	Yes
Simplicity	Yes ?	?	?	?	?	Yes
support for a local namespace prefix and an identifier part	Yes ?	?	?	?	?	Yes
support for opaque identifiers	?	?	?	?	Yes	Yes ?
Local part should not be Cornell branded	?	?	?	?	completely flexible	Yes ?
may be surrogate for physical object	? Yes	?	?	?	?	Yes
should be short (so use 26 letters plus numbers)	? Yes	?	?	?	?	Yes
should be easy to copy by hand	?	?	?	?	depends on the length	depends on the length and/or layout?

For Resolver and System

	HDL	PURL	PURLz	HNRS	DOI
Supports billions of identifiers	?	?	?	?	?
Robust architecture	?	?	?	?	?
Robust implementation	?	?	?	?	?
Don't know; limited to the practical capacity of the underlying database.	Don't know – mention of 1996 tests resolving 50 resolutions/sec with a database of 500,000 PURLS in Long Introduction to PURLs
Robust architecture	Yes	Yes; PURLz is just a simple HTTP server using MySQL
Robust implementation	Yes	No - alpha stage
ability to request metadata about the identifier	?	?	?	?	Yes	Yes ?
lightweight understanding of identifier equivalence	?	?	?	?	Yes	Cloning an existing PURL and chaining a PURL ?
should be easily discoverable by Google	?	?	?	?	?	Yes; the resolvers can't be crawled without providing a dump	Yes; the resolvers can't be crawled without providing a dump
integrate well with the "web architecture"	?	?	?	?	Yes	Yes ?
vitality checking	?	?	?	?	?	not built in
Need to avoid unbounded generation of surrogate persistent identifiers?	?	?	?	?
PID corresponding to every Cornell NetID	?	?	?	?	?	Depends on the Partial Redirect working – e.g., http://resolver.cornell.edu/netid/bdc34

Governance Issues

	HDL PURL	PURLz	HNRS	DOI
Requires payment to external organization	?	?	?	?	?	one-time $50 payment per named resolver (not mirrors)	no
Can continue resolve IDs in absence of external organization	Yes?	?	?	?	?	Yes

HDL is Corporation of National Research Initiatives's Handle system.
PURL is OCLC's PURL system.
PURLz is Zepheira's and OCLC's new persistent URL work.
HNRS is the Harvard Name Resolution Service.
DOI is IDF's DOI system

Footnotes

Anchor
unique
unique
Uniqueness: We think PURLZ will reject the creation of a duplicate PURL, but we're not entirely sure how it deals with duplication when a PURL name component overlaps a PURL domain component – e.g., if we inadvertently created a domain /a/b/ with resource 1234 and someone later used the name b/1234 in domain /a/. Maybe pure string comparison for non-uniqueness is all that's required, but conventions need to be established to avoid confusion.

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Versions Compared

Old Version 15

New Version Current

Key

For Identifiers (just the complete URI and local part, not about mechanisms)

For Resolver and System

Governance Issues

Footnotes