A Reference and Planning Model for Library Online Public Access Catalogs

This dissertation explores the problem of how library catalogs can be connected or combined, providfng library users with access to materials beyond the local library collection while maintaining local autonomy and ease of implementation. The first step in solving the problem was to identify the fundamental ways library systems can be connected, and to determine the characteristics of each. The Reference Model for Online Public Access Catalogs (OPAC Model) does this by categorizing the basic architectures into three models: centralized, distributed and stand-alone. The reference model provides a way to classify a system according to its architecture and identifies the basic characteristics that a system must have. The distributed model (DLN Model) is explored in depth because it is the least well understood of the models and because the characteristics of distributed systems must be standardized if such systems are to be connected effectively. Whereas the OPAC Model defines the system architectures, the Library Systems Architecture Planning Model (LSAP Model) provides a tool for choosing among them. The system characteristics defined in the reference model are included to meet real-world needs, such as providing access to another library's holdings or preserving local autonomy. The LSAP Model follows from the Reference Model by making explicit the connection between a set of system characteristics and a set of environmental characteristics.