The creation of an NSDL raises the challenge of overcoming the World Wide Web's weaknesses without losing its strengths -- providing selectivity without excessive screening, providing assured links without inhibiting the provision of the most recent information, and serving as a stable platform without being overly restrictive in its operating rules. An NSDL should provide an open, robust, and reliable framework for significant advances in SMET education at the same time as it serves as a vehicle for dissemination of the best current SMET education content and practice.
The success of the World Wide Web is, in large part, a consequence of the philosophy on which it is based. There are enough standards to enable it to work but, because its architecture is open, it has been able to evolve. An NSDL would add another layer of standards while maintaining the open architecture of the Web. The new standards would include metadata and digital object identifiers that would help users find appropriate and high quality resources. They would also provide a measure of reliability and stability that is missing now from the Web. New interoperability and reusability standards would facilitate connections between disciplines and real progress, as new resources build on previous ones.
Words like "federated" and "distributed" are often used to describe the potential architecture of an NSDL. The terminology of object-oriented programming may also be useful. An NSDL is likely to consist of three broad classes of objects:
The object metaphor is useful both as a way of describing the complex interactions of the library's components and as a way of describing their interchangability. Whenever possible, the library's components, especially its services, will be described functionally so that they can be combined in various ways and replaced by better implementations as they become available.
Central Coordinating Body
The library will require a strong but relatively small central body charged with coordinating and setting standards for the library as a whole and for its components. It will set technical standards to insure interoperability, stability, and reliability. One vision of the library foresees two different kinds of collections -- full partners and associates. Full partners would adhere to higher standards than associates. For example, full partners would emphasize quality whereas associates might be more concerned with currency and the availability of works-in-progress or "gray papers." The central coordinating body would set standards for different kinds of collections.
The central coordinating body might also provide mechanisms for identifying and supporting the development of necessary services and for stimulating the development of balanced collections to ensure coverage of all the SMET disciplines.
One vision of the library is based on hundreds (more than tens and less than thousands) of collections, each maintained by a strong institution or consortium -- for example,
Collections might be organized along very different lines depending on the interest and expertise of the sponsoring institution -- for example, some collections might specialize in
The library's services are the key to serving the user community effectively. Some services will serve users directly; others will serve collections; and still others will serve other services. The list of services might include, among others: