Digital Libraries

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Interoperability

Ideally all of the online libraries would be connected together sharing resources and servicing users using mechanisms that are totally transparent to anyone. This is the ultimate goal of interoperability in digital library research.

Collection Heterogeneity

The largest problem in achieving interoperability derives from dealing with the diverse distinct methods digital libraries currently use for the storage and representation of their collections. This problem is currently being attacked through the use of remote computation methods/agents. These interoperability agents are small network programs or applets that can accept distributed digital library documents and render the documents to a user in a data independent format. These programs are currently under development as Java applets, CORBA or DCOM components. (CORBA and DCOM components allow for the writing of computer platform/system independent programs.)

Early work on this problem is present in document composition collaboration systems. These systems allow multiple authors to write together, with different tools, and then synchronize the document together to achieve consistency and format independence.

Standards

In order to reach desired interoperability levels, the digital library research community realized early on that higher levels of document representation and retrieval were needed. The earliest work in this area helped result in the Web's document markup format, (HTML) and transportation mechanisms, (HTTP, MIME). Later work has yielded the International Organization for Standardization (ISO) Z39.50 protocol. The Z39.50 protocol allows for uniform information searching and retrieval from disparate information sources. An early draft of the Z39.50 protocol served as the basis for WAIS.

A current prevailing use of this paradigm is being made at CIMI (the Consortium for the Computer Interchange of Museum Information). CIMI is a large scale attempt to acheive interoperability across museums and libraries.

A related approach is being taken by the Networked Digital Library of Theses and Dissertations, (NDLTD). Through the use of platform independent document formats, (PDF - Portable Document Format and SGML - Standard Generalized Markup Language), the NDLTD is creating a national digital library of electronic thesis and dissertations. The Director of the NDLTD project is Dr. Edward Fox, Professor of Computer Science at Virginia Tech.