Realizing and maintaining aggregative digital library systems: D-NET software toolkit and OAIster system

Aggregative Digital Library Systems (ADLSs) provide end users with web portals to operate over an information space of descriptive metadata records, collected and aggregated from a pool of possibly heterogeneous repositories. Due to the costs of software realization and system maintenance, existing "traditional" ADLS solutions are not easily sustainable over time for the supporting organizations. Recently, the DRIVER EC project proposed a new approach to ADLS construction, based on Service-Oriented Infrastructures. The resulting D-NET software toolkit enables a running, distributed system in which one or multiple organizations can collaboratively build and maintain their service-oriented ADLSs in a sustainable way. In this paper, we advocate that D-NET's "infrastructural" approach to ADLS realization and maintenance proves to be generally more sustainable than "traditional" ones. To demonstrate our thesis, we report on the sustainability of the "traditional" OAIster System ADLS, based on DLXS software (University of Michigan), and those of the "infrastructural" DRIVER ADLS, based on D-NET.