PRINCIPLES OF DIGITAL LIBRARIES

The purpose of a digital library is to provide coherent organization and convenient access to typically large amounts of digital information. The following principles provide working definitions of a digital library from both a conceptual and a practical standpoint:

• A digital library is an integrated set of services for capturing, cataloging, storing, searching, protecting, and retrieving information.
• Digital library services bring order where data floods and information mismanagement have caused much critical information to be incoherent, unavailable, or lost.
• Digital library architecture emphasizes organization, acquisition, preservation, and utilization of information.
• Digital library systems are realizations of an architecture in a specific hardware, networking, and software situation.

Core Capabilities of Digital Library Systems

Digital library systems compose a family of automated systems that together provide a comprehensive capability to manage the digital content of an enterprise. It is useful to divide the capabilities of digital library systems into the following areas:

• capture or creation of content
• indexing and cataloging (metadata)
• storage
• search and query
• asset and property rights protection
• retrieval and distribution

Content exists in multiple sizes, formats, and media, each with accompanying technical challenges. Content may be structured or unstructured. It may have exact, precise meaning; or it may be fundamentally ambiguous. Content may directly or indirectly support a business process or function.

A digital library architecture shows how capabilities are realized and related, and does this at several levels. Digital library architectures show how business processes or functions are enhanced; they show how technology components fit together and how, in detail, components interoperate with each other.

Such functions and relationships, when reduced to a particular software and hardware implementation, lead to operational digital library systems.

Digital Libraries and Traditional Libraries

Digital library functions, insofar as they purport to organize information, may be compared with traditional library functions. Consider digitization, which technically is the conversion of analog to digital formats. A common human artifact, such as a bound book, loses value when simply scanned into bits. In a library context, where organization, access, protection, and preservation are important business functions, digitization technologies are starting points for a complicated set of computational processes that in the first instance reconstruct the cultural, conventional, and intuitive significance, structure, and external relationships that defined the original artifact. Additionally, digitization and other processes may be able to add value and support certain fiduciary responsibilities that resemble functions of traditional libraries.

In a similar way, other core capabilities of traditional libraries can be transposed to the digital domain. Cataloging is transposed to the generation of metadata, and is an area where much work needs to be done to develop automated, multidimensional indexing and cataloging procedures. Just as the public card catalog is a gateway to the holdings of a conventional library, search of content and metadata is the gateway to a digital library. Circulation in a conventional library transposes to network access, retrieval and delivery.

The fiduciary responsibilities of traditional libraries are related to issues of copyright protection and intellectual property rights. Table 4.1 relates digital library capabilities to well-known capabilities of traditional libraries. The point is that traditional libraries have established uniform business processes and highly interoperable data formats which support especially bibliographic catalogs, item ordering, and interlibrary loan. Although many of these procedures pre-date "digital" libraries, digital library design can benefit from the comparisons.

Having made these comparisons, it must be emphasized that neither in the United States nor in Japan is the digital library regarded as a technology related to library automation or the provision of integrated library systems for operating traditional libraries. None of the digital library projects visited in Japan either utilized or were based on library automation technologies. On the contrary, the panel saw digital library technologies, which very strikingly enabled the digital library capabilities enumerated in this chapter, creating new lines of business in both public and private endeavors.