Table 2.
Identifier scheme persistence and object removal behavior.
| Identifier scheme | Achieving persistence | Enforcing persistence | Action on object removal |
|---|---|---|---|
| DataCite DOI | Registration with contracta | Link checking | DataCite contacts owners; metadata should persist |
| CrossRef DOI | Registration with contractb | Link checking | CrossRef contacts owners per policyc; metadata should persist |
| Identifiers.org URI | Registration | Link checking | Metadata should persist |
| HTTPS URI | Domain owner responsibility | None | Domain owner responsibility |
| PURL URI | Registration | None | Domain owner responsibility |
| Handle (HDL) | Registration | None | Identifier should persist |
| ARK | User-defined policies | Hosting server | Host-dependent; metadata should persistd |
| NBN | IETF RFC3188 | Domain resolver | Metadata should persist |
Notes.
The DataCite persistence contract language reads: “Objects assigned DOIs are stored and managed such that persistent access to them can be provided as appropriate and maintain all URLs associated with the DOI.”
The CrossRef persistence contract language reads in part: “Member must maintain each Digital Identifier assigned to it or for which it is otherwise responsible such that said Digital Identifier continuously resolves to a response page…containing no less than complete bibliographic information about the corresponding Original Work (including without limitation the Digital Identifier), visible on the initial page, with reasonably sufficient information detailing how the Original Work can be acquired and/or a hyperlink leading to the Original Works itself…”
CrossRef identifier policy reads: “The … Member shall use the Digital Identifier as the permanent URL link to the Response Page. The… Member shall register the URL for the Response Page with CrossRef, shall keep it up-to-date and active, and shall promptly correct any errors or variances noted by CrossRef.”
For example, the French National Library has rigorous internal checks for the 20 million ARKs that it manages via its own resolver.