The aDORe Archive is a write-once/read-many storage approach for Digital Objects and their constituent datastreams. The approach combines two interconnected file-based storage mechanisms that are made accessible in a protocol-based manner.
First, XML-based representations of multiple Digital Objects are concatenated into a single, valid XML file named an XMLtape. The creation of indexes for both the identifier and the creation datetime of the XML-based representation of the Digital Objects, facilitates OAI-PMH-based access.
Second, ARC files, as introduced by the Internet Archive, are used to contain the constituent datastreams of the Digital Objects in a concatenated manner. An index for the identifier of the datastream facilitates OpenURL-based access.
The interconnection between an XMLtape and its associated ARC file(s) is provided by conveying the identifiers of these ARC files as administrative information in the XMLtape, and by including OpenURL references to constituent datastreams of a Digital Object in the XML-based representation of that Digital Object stored in the XMLtape.
The aDORe Archive Solution provides:
- Storage of compound objects (independent of the choice of complex object format, i.e. MPEG-21 DIDL, METS, …)
- Two interconnected file-based storage mechanisms:
- XMLtapes: File storage of XML-based representations of Digital Objects
- ARC files: File storage of constituent datastreams of Digital Objects
- An XMLtape is interconnected with one or more ARC files during the ingestion process
- Protocol-based access mechanisms:
- Each XMLTape is exposed as an autonomous OAI-PMH repository
- Each ARC file is exposed as an OpenURL Resolver
- Long-term stability:
- Write once – Read many approach
- XMLtapes and ARC files remain stable over time, while indexing mechanisms can change as technologies evolve
- Protocol access remains stable over time as indexing technologies evolve
- Capability to store multiple XMLtapes and ARCfiles.