Abstract: Most hypermedia systems are currently implemented as closed, monolithic applications that effectively isolate information and functionality from other applications in a computing environment. Open architectures, on the other hand, tend to promote a higher degree of information and tool integration. In this paper, we report on the design and implementation of an open, multi-user hypermedia system called System Prototype 2 (SP2).
SP2 implements an object-based architecture for distributed, inter-application linking. It is an instantiation of a conceptual model that abstracts information, structure, and behavior from hypermedia. SP2 allows hypermedia connections to be forged and navigated among applications that are able to participate in a distributed link services protocol. The functionality of the system is realized by client/server relationships among several software components: Participating Applications, a Link Services Manager, and the HB2 hyperbase management system which provides persistent storage for objects and structural data.
SP2 allows application-level extensibility, the independent extensibility of hypermedia functionality, and extensibility at the data management level. We discuss our experiences with SP2 and describe why this approach to architectural openness can significantly improve the applicability of hypermedia technology to many large-scale, information intensive domains.