BND: the architecture of a National Digital Library

We describes the architecture and components of the infrastructure in construction for the National Digital Library in Portugal. The requirements emerged from the definition of the services to support, with a special focus on scalability, and from the decision to give a special attention to community building standards, open solutions, and reusable and cost effective components. The generic bibliographic metadata format in this project is UNIMARC, and the structural metadata is METS. The URN identifiers are processed and resolved as simple but very effective PURL identifiers. The storage for immediate access is provided by the LUSTRE file system, and by ARCO, a locally developed GRID architecture, for long term preservation. All these components run on Linux servers, as also the middleware for access based in the FEDORA framework.