Code4Lib Journal (Jul 2013)

The Moab Design for Digital Object Versioning

  • Richard Anderson

Journal volume & issue
no. 21

Abstract

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The Stanford Digital Repository has adopted the "Moab" design for versioned archiving of digital objects--a locally developed approach that optimizes data transfer, storage, and replication while providing efficient single file retrieval or full object reconstruction for any version of an object. This paper includes a review of various versioning strategies including forward-delta, reverse-delta and content-addressable mechanisms, the pro's and cons of each, and highlights the relative advantages of the Moab design. In our approach, the fixity information of a file manifestation is used as its primary identifier and the filename is treated as metadata. Storage and retrieval of an object's files is faciliated by mapping between a virtual version inventory and the physical location via a file signature catalog.