1,2, July 2011
The National Archives of Australia (the Archives) undertakes to ensure the long-term preservation and accessibility of the archival resources of the Commonwealth which were created or managed in a digital format.
Digital preservation is the process of active management by which the National Archives ensures that a digital object will be accessible in the future.
The National Archives aims to preserve any type of digital record that is:
The preservation of digital records represents a significant challenge for both government agencies and archival institutions. Factors affecting the level of risk include:
The inherent instability and vulnerability of digital records affects the ways in which the Archives secures, manages and preserves digital records.
Under the Archives Act 1983 the National Archives is responsible for preserving Commonwealth records that form the archival resources of the Commonwealth. These include born-digital records and digital preservation master copies of analog originals.
The Archives only accepts records from government agencies that have been sentenced Retain as National Archives (that is, for permanent retention) under a records authority. ('Sentencing' is a process of using a records authority or other instrument to decide whether to retain, destroy or transfer a record. Records authorities are issued to individual agencies by the National Archives and cover agency-specific core business.) In exceptional circumstances the Archives will accept records whose value has not been identified, for example records that are at risk or are considered a significant resource.
The Archives does not preserve the means used to create, manage or present digital records, for example records management software. The Archives accepts exports of digital records and their metadata from systems, not exports of the systems themselves.
The Archives' digital preservation capability:
The Archives converts digital records to fully-specified, standards-based open formats (that is, formats whose specification is fully and openly published). The conversion occurs when the records are ingested into the Digital Archive. This is a 'migration' approach to digital preservation that limits the number of preservation treatments applied to each digital record, thereby minimising the risk of altering or damaging the record.
This approach is referred to as ‘normalisation’ because the Archives converts digital records to a small number of open ‘preservation’ formats. The Archives also retains a copy of the original digital record to return to if a chosen preservation format is superseded, or if a better approach is developed. In this way the Archives ensures sustainability and flexibility.
The Archives uses preservation formats selected through a rigorous research and testing regime. The Archives assesses potential preservation formats against the following criteria:
In some cases, documents are unable to be converted into an open format. Reasons for this include:
The Archives stores these documents in their existing format and reprocesses them when the appropriate ‘normaliser’ is available.
The Archives cannot guarantee that the conversion process results in an absolutely identical document. For example, not all of the fonts in an original word processing document may be available on the system used to view the normalised version.
However, the Archives endeavours to capture those characteristics of the original record that are essential to preserve its meaning. For example, for documents the Archives will preserve the content and enough of the appearance, structure and context of the original record to convey the originator's intentions. By preserving the essential characteristics of digital records, the Archives ensures that records retain their value as evidence.
The Archives uses the best conversion technology available at the time of conversion. It also has the capability to convert either the original or normalised versions again if better conversion methods are developed.
The Archives is committed to collaborating with other Commonwealth agencies, archival institutions with an interest in digital preservation, and other stakeholders to advance the development of digital preservation tools and processes, share lessons learned and develop expertise in digital preservation domestically and internationally.