摘要：Repositories used to be fairly monolithic systems, with a single object store, a tailored content model, and a dedicated application on top. The federation protocol OAI-PMH for content aggregation is an exception to this. However, we are still far away from an open repository environment, in which repositories interact on all levels with other agents (e.g. other repositories, added-value services, registries). This paper creates a more fine-grained view on repository federation and analyses existing approaches with regard to four interoperability attributes: syntax, structure, semantics, and patterns. Among these attributes, the most evident gap pertains to interaction patterns between agents. Besides the prevalent client-pull and harvesting patterns, notification offers a more immediate and directed mechanism, enabling new federation scenarios and laying the grounds for open repository environments. Prototypes of the concepts presented here are being implemented in the scope of the project DARIAH, which establishes an e-Infrastructure for the humanities.
