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Version 1.0 of the Oxford Common File Layout (OCFL) Released

We are pleased to share the news about the first release of the Oxford Common File Layout (OCFL), officially announced earlier this month. This milestone is the cumulation of almost three years of steady collaboration between the Bodleian Library of Oxford University, Emory University, Cornell University, Lyrasis and Stanford Libraries.

The OCFL is an application-independent approach to the storage of digital information in a structured, transparent, and predictable manner. It does this by specifying how the files that constitute a digital object can be arranged in a directory following a standard structure that allows for updates and consistency checking, which in turn facilitates other systems' ability to preserve that data for the long term. A guiding principle is that file systems and layouts change less frequently than the applications that use them; thus by having a simple, open standard that many different applications can follow, the OCFL enables interoperability between different preservation systems and makes it easier to preserve and maintain content over the long term.

The OCFL draws inspiration and lessons from prior art, notably the Moab object specification developed by Stanford Libraries in 2013 and currently used in the preservation layer of the Stanford Digital Repository. The OCFL adopts many of the design decisions of Moab, including the use of forward delta file versioning, file-based deduplication, and a compatible directory layout, and adds a simplified manifest based on JSON, support for modern checksum algorithms, and the ability to extend the specification to meet local needs.

The OCFL is already used by production systems at several universities, with more institutions looking to adopt now that it has reached a 1.0 release. The OCFL has also been chosen as default persistent filestore for Fedora 6, the next version of a widely-used open-source digital repository with native linked data support.

We are proud to be actively involved in the development of OCFL as a community-based approach with the potential for widespread adoption and thus a profound impact on the long term preservation of the world’s digital information.

Further reading:

Submitted by Julian Morley, Co-Editor of the OCFL v1 specification