Fedora provides the back-end foundation for digital repository systems responsible for managing and preserving all types of digital content.
Licensing and cost
Apache 2.0 – free.
Version 3.6.2 was released 15 November 2012. Development is ongoing. The Fedora Futures initiative was created in December 2012 to take a long-term view of Fedora development. This initiative is developing Fedora 4.0, re-architecting the software to accommodate recent software and technology advances as appropriate.
Platform and interoperability
Fedora is written in Java, and was tested under Linux, Solaris, Windows, and Mac OS X.
In the Fedora digital object model, an object consists of a persistent identifier, an XML document for object properties, and a number of datastreams each holding a content file or metadata record (the object can have more than one of each). Each object can assert relationships to any number of other objects using RDF. The XML object properties documents contain information such as an audit trail of actions that have affected the object and policies about the object; as long as these files, along with the content itself, are backed up properly, they can be used to reconstruct an entire running instance of the repository without relying on any external software. While the Fedora Repository is capable of operating as a standalone content server, it is designed for use with other software to provide full system functionality. Such software might include authoring or ingest applications, search engines, workflow management, or security components such as user identity management.
Documentation and user support
The Fedora Commons community is extensive, with active user and developer mailing lists; DuraSpace also hosts a Fedora wiki, which includes tutorials, user and installation guides, and other resources. The Fedora site also links to a number of registered service providers, which offer assistance with design, installation, and implementation.
Fedora provides a web-based Administrator GUI for low-level object editing; users, however, interact with the repository using APIs for management, access, search, and queries. Usability more broadly is dependent on the interfaces that the system administrator has chosen as front ends for the APIs: this model was chosen so that different interfaces can be designed to suit different needs. The Fedora wiki includes a registry of community-developed software that provides these kinds of interfaces; frameworks to facilitate such development include Hydra and Islandora.
Installation and configuration require detailed system administration knowledge, as well as expertise in XML and interface design. The Hydra and Islandora frameworks seek to alleviate this by 'hiding' Fedora behind simpler system environments based on Ruby on Rails and Drupal, respectively.
Fedora supports OAI-PMH (and by extension, Dublin Core and other metadata standards), and also provides support for RDF.
Influence and take-up
The Fedora Commons Registry lists nearly 200 organisations with Fedora instances, from broadcast services such as WGBH, to government agencies such as the U.S. Centers for Disease Control and Prevention, to academic archives such as Oxford University.