Writing in the Sand Preservation Metadata (PREMIS) in Digital Libraries

Preservation Metadata Implementation Strategies (PREMIS) is a joint effort of RLG and the library consortium OCLC. Preservation metadata is information that supports digital preservation processes. A key component of archival systems, metadata helps to ensure that digital materials remain usable over the long term. Without detailed knowledge of the file type, composition, relation of parts, dependence on particular software or hardware, restrictions, creation mechanisms, and more, the digital object cannot be successfully stored, migrated, preserved, or restored.

Following publication of the PREMIS Working Group's PREMIS Data Dictionary for Preservation Metadata a maintenancy activity was launched for that guide and supporting XML implementation schemas, hosted by the Library of Congress. Work is underway to develop a maintenance agency, to fund inter-institutional PREMIS operability testing, and to apply the results to revisions of the data dictionary and XML schemas.

The PREMIS work build on the Open Archival Information System (OAIS) Reference Model (ISO14721), and defines "preservation metadata as the information a repository uses to support the digital preservation process. This information spans the categories of administrative (including rights and permissions), technical, and structural metadata.

The PREMIS Data Model has five basic components: Objects, Intellectual Entities, Events, Agents, and Rights:

  1. An Object, or Digital Object, is a discrete unit of information in digital form.
  2. An Intellectual Entity is a coherent set of content that is reasonably described as a unit, for example, a particular book, map, photograph, or database. An Intellectual Entity can include other Intellectual Entities; for example, a Web site can include a Web page, a Web page can include a photograph. An Intellectual Entity may have one or more digital representations.
  3. An Event is an action that involves at least one object or agent known to the preservation repository.
  4. An Agent is a person, organization, or software program associated with preservation events in the life of an object.
  5. Rights, or Rights Statements, are assertions of one or more rights or permissions pertaining to an object and/or agent.

Each description applies to one and only one resource; if the resource is altered in any way, it becomes a new resource, requiring a new preservation record. For more information, please read the PREMIS Data Dictionary from which this information was taken.

Background on the PREMIS activity is described in an article by Brian F. Lavoie, "Implementing Metadata in Digital Preservation Systems: the PREMIS Activity" (D-Lib Magazine, April 2004, 10:4).

Recommended listserv: Premis Implementer's Group.

Girl writing in the sand

This information is provided without guarantees as to validity or completeness, particularly in light of the fact that the world of metadata in digital libraries is a world of shifting sands, constantly changing.