Some Strawman Amendments to the Identifier WD

• Part A.
• Part B.
• Part C.
• Part D.

Part C. Support for Persistance and Location-independence: Persistant Logical Identifiers (PLI).

Persistance:

• add an attribute "persistant" to the Resource Identifier element with default value = true, indicating that the identifier is permanently associated with the resource and will never be associated with another resource in the future. False indicates that the name is temporary and valid only in some limited context.

• add attribute "status" to Resource element with possible values

  "active"

  resource is believed to be currently maintained and description is up to date (default).

  "inactive"

  resource is apparently not being maintained at the present.

  "deleted"

  resource publisher has explicitly deleted the resource.

• metadata for a resource with a persistant identifier may be updated. Registries, however, are discouraged from removing resources from their contents; rather, the resources should be marked with status="deleted".

Note: a searchable registry may by default constrain search results to those resources of a particular state (e.g. active) or states (e.g. not deleted).

Location-independence

This proposal is intended to be built on top of the Identifier, Resource metadata, and Registry standards.

• Add to the generic Resource metadata an additional identifier, called "LogicalIdentifier". Its default value is the value of the resource's Identifier.

• A URN form for a LogicalIdentifier is defined.

• Data providers should not give the same "LogicalIdentifier" to separately registered resources unless they are mirrors.

• Mirrorable resources are ones with the Identifier attribute, persistent="true".

• Add to the metadata schema terms that allow a resource to assert:
  • "I'm a mirror of another resource"
  • "These are the list the resources that mirror me."

• If a resource claims to be a mirror of another resource, it must explicitly set its "LogicalIdentifier" to the that of the resource being mirrored.

• If curation of a resource changes from one organziation to another, the new version is given a new Identifier, tagged with the metadata indicating that it is a mirror of the original, and assumes the original's "LogicalIdentifier". The original is the marked deleted.

• The searchable registry interface should provide a by-LogicalIdentifier look-up that returns all resources having that LogicalIdentifier.

• All resources having the same LogicalIdentifier are not guaranteed to be mirrors of each other. The resource mirroring metadata should checked to confirm logical equivalence.