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CDL Guidelines for Digital Objects, Version 2.0: Updated for METS File element

By Adrian Turner, CDL Data Acquisitions

The “CDL Guidelines for Digital Objects, Version 2.0” (CDL GDO) has been updated to include specifications for use of the METS File <file> element.  You can find the updated version at .

The revision applies to Sections 2.1, 2.2.2, 3.1, and 3.2.4 only:

  • To support the orderly transmission and ingest of digital objects, the CDL recommends the inclusion of checksum (MD5, SHA-1, or CRC32) and byte size values in the METS File <file> element.  Note that this information is preferred, but not required.
  • The subheadings within Sections 2.1 and 3.1 have been relabeled, and are now consistently based on METS element names.

Please contact the CDL at if you have any questions.