The German Remote Sensing Data Center (DFD) has developed a digital library for the long-term management of earth observation data products. This Product Library is a central part of DFD’s multi-mission ground segment Data Information and Management System (DIMS) and is successfully in operation since 2000. Its data model is regularly extended to support products of upcoming earth observation missions. The Product Library implements a middleware filling the gap between application-level object data models and physical storage structures such as a digital robot archive with hierarchical storage management. This paper presents the principles of the Product Library middleware and its application in the specific earth observation context.