Digital Archive Directions (DADs) Workshop

(A part of the ISO Archiving Workshop Series)


Position Paper

Digital Archive Directions (DADs) Workshop

DATE: June 22-26, 1998

HOST: The National Archives and Records Administration
Archives II
8601 Adelphi Road
College Park, MD 20740-6001



1. Identification of Proposed Topic [Required]

1.1 Title

Considerations for External Interfaces to an OAIS

1.2 Contributor(s)

Robert H. Bourdeau
2250 Pierce Rd.
University Center, MI, 48710
(517) 797-2794

1.3 Description of Proposed Project

The OAIS Reference Model embodies many of the current best practices related to architectures for modern data archives. However, it would appear that, even with the release of Issue 3.0, the OAIS still retains a focus on access to data in its archived format and in packages of which the structure is limited by the granularity of the archived objects. While this model of access may be suitable for many applications, this author is of the opinion that a more generalized view of the archive provides greater flexibility for new applications that would draw upon the content of the resources managed by the archive. In this position paper, several applications are presented that illustrate where interfaces to the archive can either be clarified or enhanced in order to facilitate cost effective implementation.

1.4 Justification

The Socioeconomic Data and Applications Center (SEDAC) is a NASA funded data center, developed and operated by CIESIN, that is part of the NASA Earth Observing System Data and Information System (EOSDIS). Of the nine funded data centers under EOSDIS, eight will be operating the data system known as the EOSDIS Core System (ECS), while the ninth center, SEDAC, develops its own approach to data and application delivery. In its recently awarded proposal for the SEDAC, CIESIN proposed to reengineer its data and information services according to the OAIS reference model- then Issue 2.0. Several extensions to OAIS were proposed in the SEDAC proposal to allow for the implementation of interactive services per SEDAC's mission. These extensions included Standard and Special Processing subsystems, and special considerations for the Data Management and Access subsystems.

Work on the SEDAC-proposed OAIS implementation will proceed over the next two years as a reengineering effort with special attention to the integration of a variety of standards into the OAIS framework. Some of these enhancements are beyond the scope of the OAIS as a reference model, but others are of direct interest to the OAIS. This paper will discuss the needs presented by the SEDAC, and how the current OAIS does and does not meet these needs.

1.5 Definitions of Concepts and Special Terms

"Consortium for International Earth Science Information Network" is a non-profit corporation. It will soon become the "Center for International Earth Science Information Network" of Columbia Unversity as part of the Columbia Earth Institute, and will be located at the Lamont-Doherty Earth Observatory. Lamont is also the home of a vast number of important scientific datasets that could be considered for archiving and access through the SEDAC's implementation of an OAIS."

1.6 Expected Relationship with OAIS Reference Model

Most significant to the SEDAC are the following areas:

  • interfaces between OAIS-type archives (aka, interoperability)
  • mechanisms of Access subsystem to support access to the archive by new and emerging web technologies.
  • protocol standards for search and retrieval of archive metadata information.
  • extensional representations of archive holdings.
  • interfaces for exploration of archive holdings."



2. Scope of Proposed Standard [Desired]

2.1 Recommended Scope of Standard

I am still reviewing Issue 3.0, and have not yet determined what is now well-understood. Depending on how well some of the areas outlined above are represented by other workshop participants, I could focus in on one of the areas less well covered.

2.2 Existing Practice in Area of Proposed Standard

With respect to information retrieval, CIESIN and the SEDAC currently utilize Z39.50 for access to its metadata holdings.

We also have a significant human component to the Ingest component since our data does not commonly arrive in steady data streams. It's often higher- level data for which signficant effort has been expended in the production of each granule.

2.3 Expected Stability of Proposed Standard with Respect to Current and Potential Technological Advances

We expect significant changes in component technology to force changes in designs and implementations within 3-4 year time frames. As such, strategic loose-coupling between components is essential to ensure that systems can indeed evolve with the advent of new technologies.

Wider Views

Overview of the DADs Workshop
Overview of US Effort
Overview of International Effort


A service of NOST at NSSDC. Access statistics for this web are available. Comments and suggestion are always welcome.

Author: Robert H. Bourdeau ( +1.517.797.2794
Curator: John Garrett ( +1.301.286.3575
Responsible Official: Code 633.2 / Don Sawyer ( +1.301.286.2748
Last Revised: May 11, 1998, Robert H. Bourdeau (May 26, 1998, John Garrett)