The Open Archival Information Systems (OAIS) Reference Model is a conceptual model for a digital archive. Much of the terminology used in digital preservation comes from this model, which was turned into an ISO Standard in 2002. The OAIS Reference Model describes the environment, functional components, and information objects associated with a system responsible for the long-term preservation. As a reference model, its primary purpose is to provide a common set of concepts and definitions that can assist discussion across sectors and professional groups and facilitate the specification of archives and digital preservation systems. It has a very basic set of conformance requirements that should be seen as minimalist. OAIS was first approved as ISO Standard 14721 in 2002 and a second edition was published in 2012. Although produced under the leadership of the Consultative Committee for Space Data Systems (CCSDS), it had major input from libraries and archives.
The DCC Lifecycle Model further expands on the idea that digital preservation requires actions throughout the lifecycle to ensure sustained long-term access to digital assets. The model is often used in the digital curation and research data management sectors, but it reflects the same actions and workflow used throughout the digital preservation field.
There are a number of key elements to the Lifecycle, starting from the data in the centre; this is what we are trying to preserve. The model then moves outwards to various dependencies and actions in order to preserve and provides access to that data. These actions include full lifecycle, sequential and occasional actions.
The first element in the centre of the Lifecycle is DATA, which is any information in binary form, including:
Digital Objects: these are defined as follows in the Lifecycle model. Simple digital objects (discrete digital items such as text files, image files or sound files, along with their related identifiers and metadata) or Complex digital objects (discrete digital objects made by combining a number of other digital objects, such as websites).
Databases: structured collections of records or data stored in a computer system.
Created by Anne Kenney and Nancy McGovern for the Digital Preservation Management Workshops in 2003-2006, this stool represents the three aspects of a successful and sustainable digital preservation programme:
What the model demonstrates, is that without considering and maintaining each of these components (or "legs"), a digital preservation programme will ultimately collapse. These three components need to be considered together in order to sustain digital preservation activity.
It is important that a programme does not consider technology as the only solution and that a balance is struck between the technology, the people, the funding and the organizational policies.
Preservation Metadata Implementation Strategies (PREMIS) is a metadata standard for recording information required for preservation of digital objects. The standard's documentation and metadata schema are hosted by the Library of Congress. Their website states:
"The PREMIS Data Dictionary for Preservation Metadata is the international standard for metadata to support the preservation of digital objects and ensure their long-term usability. Developed by an international team of experts, PREMIS is implemented in digital preservation projects around the world, and support for PREMIS is incorporated into a number of commercial and open-source digital preservation tools and systems. The PREMIS Editorial Committee coordinates revisions and implementation of the standard."
Aside from associated documentation, there are two main components to the PREMIS standard:
To learn more about PREMIS, please visit: http://www.loc.gov/standards/premis/