Features of the Alliance Digital Repository

Fully Hosted Service

ADR Services centrally manages all the hardware, software, updates, and backups for the repository.

Customization with Drupal

Customize the look and feel of the repository front end with the Drupal web content management system.

Access and Authentication

Manage restricted, embargoed, or dark archive content with user accounts and security metadata.

Content Loading

Add content to the repository with easy web forms for adding metadata and attaching files.


Solr indexes metadata and the full text of PDFs and other documents, which can be searched with simple and advanced search functions.

Streaming and Viewing

Embedded viewers and players display common formats of document, image, audio, and video content without users having to download anything from the repository.

Cloud Storage

Back up objects in the cloud and perform fixity checks with DuraCloud.

Content Sharing

Share OAI metadata for harvesting and aggregation into other sites. Every object is assigned a Handle link for persistent identification.


Fedora Commons open-source repository software supports management, reuse, migration, and transformation activities on digital objects for access and preservation.


ADR hardware is stored at a collocation facility to meet power, cooling, and security needs. Data is backed up to disk and tapes. For more information about the ADR hardware, please contact


The ADR Basic repository platform runs on Islandora, an open-source Drupa-based repository system, and uses Fedora Commons as its core repository software. For a detailed list of applications and software being used in ADR Basic, see the ADR Services Wiki.

Cloud Storage

In 2010, ADR Services participated in a pilot project for DuraCloud, cloud repository management software from DuraSpace, the parent organization of Fedora Commons. In fall 2011, the ADR joined the DuraCloud service and will begin using its cloud services for remote backup and bit integrity in 2012.

Descriptive Metadata

All the objects in the repository have a basic set of descriptive information in MODS (Metadata Object Description Schema), which is a set of metadata designed to describe resources commonly found in libraries. The ADR and its members follow best practices for MODS as set out by the Digital Library Federation’s Implementation Guidelines for Shareable MODS and MODS Levels of Adoption (Minimum for Doing Anything Useful).

Many ADR members do not have pre-existing MODS metadata for their records. Members can create a MODS record for an object by filling out a web form in the repository software, which then builds MODS. Alternatively, members can send metadata to ADR Services in MARC, Dublin Core, or even a spreadsheet and we will transform the metadata into MODS that can be used by the repository.

The MODS metadata is currently being used in the search index and object display, and is being transformed to Dublin Core for OAI harvesting.

ADR Basic is highly flexible with what metadata it can accept and display. Avenues for future development include objects described in VRA Core 4.0 or Darwin Core.

Security Metadata

The ADR uses XACML security metadata to control access to collections, objects, and datastreams in the repository.