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Digital Object Architecture

Note: the Digital Object Architecture Project includes the CNRI Repository.

CNRI's program of research and development in digital libraries has a number of inter-related activities that overlap and build upon each other. The work includes development of core technology that is used in several testbeds and implementation projects, with funding from a variety of sources.

See also "A Brief Overview of the Digital Object Architecture and its Application to Identification, Discovery, Resolution and Access to Information in Digital Form" at hdl:4263537/5041.

The Digital Object Architecture Project continues the architectural work of the DARPA-funded Computer Science Technical Reports Project (CSTR).


Digital Object Identifier

The project focuses on the development of an infrastructure of services that provide access to distributed and secure digital objects. Digital objects are networked objects that are named by digital object identifiers and instantiated by an infrastructure service we call a repository. Digital objects provide access to their content using an extensible and secure dissemination mechanism. Disseminations can be thought of as high level types that are uniquely distinguished by a combination of operations, and types of data the latter are performed on. Disseminations consist of mobile code called Servlet that can be designed, implemented, and registered with the digital object infrastructure by anyone with the proper permissions. Any digital object with the appropriate rights can automatically use registered servlets. This extensible dissemination mechanism enables digital objects to accommodate a wide variety of possible content, from complex to simple, static or dynamic, and from permanent to real time data. Disseminations have few operational limits and enable digital objects to dynamically generate or acquire their content.

Current ongoing research includes the development of dissemination registry, infrastructure searching, security and scalability.

Support for the Digital Object Architecture project was provided by DARPA, the Library of Congress, and the Defense Technical Information Center (DTIC), through DARPA grant MDA972-92-J-1029.



Figure 1 below shows the principal system components. CNRI's research concentrates on the concept of digital objects, the Handle System for identifying digital objects, and the Repository for storing them and making them available over the Internet. The Registry is a specialized repository that is used to authenticate digital objects.

Digital Object Architecture Diagram
Figure 1 - Principle System Components

The Handle System is a system for providing persistent names for Internet resources. It is a highly reliable, high performance, distributed system.

The Repository provides network based storage and access to digital objects. All access to digital objects passes uses a simple repository access protocol and is subject to access controls established by the manager of the repository.

The Registry is a specialized repository that provides secure registration and authentication of digital objects.



CORDRA/ADL. CNRI is designing a registration system for the ADL CORDRA project, to be known as the ADL Registry or ADL-R. This effort will enable the discovery and reuse of learning content held in repositories distributed across the DoD.


Additional Information

  • Kahn, Robert & Wilensky, Robert. "A framework for distributed digital object services"; International Journal on Digital Libraries (2006) 6(2). [doi:10.1007/s00799-005-0128-x]. Reproduced with permission of the publisher.
  • Henry Jerez, Giridhar Manepalli, Christophe Blanchi, and Larry Lannom, "ADL-R: The First Instance of a CORDRA Registry", D-Lib Magazine, February 2006. [ doi:10.1045/february2006-jerez ]
  • Giridhar Manepalli, Henry Jerez, and Michael L. Nelson, "FeDCOR: An Institutional CORDRA Registry", D-Lib Magazine, February 2006. [ doi:10.1045/february2006-manepalli ]
  • "A Design for Inter-Operable Secure Object Stores (ISOS)" by Carl Lagoze, Robert McGrath, Ed Overly, Nancy Yeager. Cornell Computer TR95-1558.
  • "Implementation Issues in an Open Architecture Framework for Digital Object Services" by Carl Lagoze and David Ely. Cornell Computer Science Technical Report TR95-1540.


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