The CDL Access and Preservation Repositories

The CDL maintains two digital object repositories, designed to support the persistent access to and preservation of collections that the CDL hosts. As of May 2005, the CDL's access repository manages over 215,000 METS records, and provides persistent public access to collections via the Calisphere, Online Archive of California (OAC), and eScholarship Editions gateways. The foundation of the University of California libraries digital preservation program, the Digital Preservation Repository (DPR) supports the long-term storage, deposit, dissemination of digital content.

The repositories conform to the following criteria:

• Objects submitted to the repositories must conform to the CDL Guidelines for Digital Objects, and must be formatted using the Metadata Encoding and Transmission Standard (METS).
• Objects in the repository are assigned persistent identifiers according to a naming scheme called the Archival Resource Key (ARK). The ARK scheme was developed at the National Library of Medicine and is currently in production use at the CDL.

Over time, the CDL plans to make many of the components of its repositories available to the digital library community. Some CDL partners are already beginning to deploy services using the CDL access repository. In March 2004, the CDL launched its redesigned Japanese American Relocation Digital Archives (JARDA) portal to use this infrastructure.

Leveraging the CDL Collection of METS Records

• Querying the METS Repository: Forthcoming documentation will describe the CGI syntax, the XML structure of the search results, and provide sample search forms for querying the collection of METS records in the CDL's access repository. Understanding how to query the collection is an important when:
  • harvesting arbitrary subsets of records from the OAI Data Service;
  • using the collection as a target for federated searching; or
  • creating deep links into the collection, including using the collection records as a targets for OpenURL resolution services.
• OAI Data Service: Provides instructions for those who wish to harvest any arbitrary subset of the CDL's METS repository using OAI-PMH 2.0.