Packaging Format Comparison

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Packaging standards for digital content include:

  • SWORD focuses on wrapping content for ingest into a digital repository. It is relatively lightweight, only storing enough information for ingest of a single item. Internal structure of the item cannot be described with SWORD, but SWORD can wrap another packaging format that does describe structure.
  • ORE expresses relationships between parts of a complex object (aka "aggregation"). It is very general, placing the burden for semantic understanding on the receiver of the package.
  • METS expresses relationships between metadata descriptions and media files, including specific offsets into the media files. It is highly structured, but can include arbitrary XML content (including SWORD or ORE objects) as well as arbitrary binary content.
  • BagIt focuses on wrapping content to ensure it travels from one location to another intact. It aims to be lightweight, providing "just enough structure to safely enclose descriptive 'tags' and a 'payload'". The 'payload' can be anything, including content in other packaging formats.
  • CMIS is an industry standard focused on providing interoperability between content management repositories. It is a relatively heavy standard. Many features mimic a file system, though doesn't require use of these features, and features are provided for more RDF-style relationships. The serialization is based on AtomPub, with extensions.

A draft specifications for package exchange, drawn up by Mike Graves: