Digital preservation consists of the processes aimed at ensuring the continued accessibility of digital materials. To do this involves finding ways to re-present what was originally presented to users by a combination of software and hardware tools acting on data.
To achieve this requires digital objects to be understood and managed at four levels: as physical phenomena; as logical encodings; as conceptual objects that have meaning to humans; and as sets of essential elements that must be preserved in order to offer future users the essence of the object.
Digital preservation can be seen as all those processes aimed at ensuring the continuity of digital heritage materials for as long as they are needed.
The most significant threats to digital continuity concern loss of the means of access. Digital materials cannot be said to be preserved if the means of access have been lost and access becomes impossible. The purpose of preserving digital materials is to maintain accessibility: the ability to access their essential, authentic message or purpose.
Digital preservation involves choosing and implementing an evolving range of strategies to achieve the kind of accessibility discussed above, addressing the preservation needs of the different layers of digital objects. The strategies include:
- Working with producers (creators and distributors) to apply standards that will prolong the effective life of the available means of access and reduce the range of unknown problems that must be managed
- Recognising that it is not practical to try to preserve everything, selecting what material should be preserved
- Placing the material in a safe place
- Controlling material, using structured metadata and other documentation to facilitate access and to support all preservation process
- Protecting the integrity and identity of data
- Choosing appropriate means of providing access in the face of technological change
- Managing preservation programmes to achieve their goals in cost-effective, timely, holistic, proactive and accountable ways.