Versioning the Dublin Core across multiple languages and over time

The Dublin Core Metadata Initiative is currently designing and implementing a registry for managing its official element and qualifier definitions over time and in multiple languages. Three aspects of this registry must be versioned: the schema that describes the elements and qualifiers, which may be accessed by software or Web agents; sets of elements and qualifiers as a whole, for which some software vendors require stable snapshots as development targets; and individual elements and qualifiers, which in their life-cycles may change in meaning or approval status. Each such event must be uniquely identifiable in a persistent way, and translations must point to the precise sources on which they were based. Versioning a metadata language such as the Dublin Core over time is a balancing act between an error-tolerant fuzziness and a desire for archival precision. This is consistent with the philosophy of a metadata pidgin language that aims at universal interoperability while recognizing the limits of the goal itself.