The British Library
Digital Preservation Policy
Last revised: 14 November 2002
The British Library aims to ensure the long term access to digital material, regardless of
format, which has been selected for retention. Digital material can be purchased, acquired by
voluntary legal deposit or created by the British Library.
The preservation of digital material is different from that of analogue material in that it requires
active and continued intervention to ensure its survival. It requires preservation decisions to be
made at the beginning of the life cycle management of the digital object.
The British Library aims to avoid loss of access to digital material, due to either media
deterioration or due to technological obsolescence of either the hardware or software.
The British Library will address both the physical and content aspects of the material. For the
physical media, the preservation aim is to slow the rate of deterioration down as much as
possible, by environmental control (including specific storage for magnetic media) and to
prevent physical damage to the media (including the use of specific handling régimes).
However the physical media is unlikely to affect the appearance of the intellectual content, and
it is therefore the content which is the primary concern of digital preservation.
For the content, the aim is to permanently preserve an original version of the material. To aid
this, the Library intends to record information specifically for preservation purposes
(preservation metadata) at the point when the material is deposited, acquired or created by
the Library, and make preservation decisions at that point. All subsequent actions undertaken
during the life of the digital object will be recorded at the time.
Strategic Approach
The British Library will build on the work of other comparable organisations engaged in the
care of national electronic written and documentary heritage, for example the National Library
of Australia. It will work collaboratively, both nationally and internationally, and with different
library and archive sectors, in the development and implementation of its preservation strategy
for digital material. It will take a lead where appropriate and play a junior partner where
appropriate. The British Library will continue to open itself to being studied whilst addressing
this relatively new area.
The British Library will
♦ develop its digital storage solutions in close collaboration with other users, for example the
Koniklijke Bibliotheek, particularly in the area of preservation
♦ be a test site for digital preservation projects for example CEDARs, LOCKSS
♦ identify and develop collaborative projects eg website archiving
♦ contribute to the development of international standards for example ISO/OAIS
♦ be studied, for example as the major case study in the AHDS research The Management
of Digital Preservation
Digital preservation strategy
The British Library anticipates that no single strategy will achieve the objective of ensuring
long-term access to all types of digital material, whether deposited, purchased and/or created
by the Library. Control of formats may be exercised over material created by the Library,
through the related British Library Digitisation Policy. Any strategy should be as flexible as
possible and not preclude future options and future development, both managerial and
technological.
Various approaches to the preservation of digital content have been identified including:
A. do nothing - take no action beyond providing shelf space
B. refresh - copy data to a new carrier of the same type
C. transfer - copy data to a more stable carrier
D. migrate - transform the data into another logical file format, possibly
one that is more software independent
E. emulate - use software that can pretend to be a different software
or operating system or hardware configuration
F. technology preservation - keep and use all old computers and old software
G.other methods - being developed by current and future research eg universal
virtual computer
The British Library believes that a subset of these strategies should be encouraged with
particular emphasis on transfer, migration and emulation. Refreshing will be a component of
any good back-up regime. There is a possibility that other developments may be introduced in
the future, and the BL will work with research projects in this area. Doing nothing and
technology preservation are seen as impracticable and unacceptable approaches to digital
preservation.
To accompany any of the above strategies the Library will aim to provide supporting
preservation functions such as maintaining preservation metadata and negotiating with
publishers to obtain a suitable digital version of material for preservation.
Principles for preservation element of digital storage solutions
The British Library will develop a system to store and manage digital material for the long
term. Its primary function is the support of digital preservation of Library collection material,
and particularly material which will be obtained by legal deposit.
Ideals of the system will include:
• as much derived data as possible will be used
• wherever possible, the processes will be automated
• the totality of the digital object will be stored
• adequate back-up regimes must be employed including off site backup. These back-ups
should not be dependant only on the existence of the British Library system.
In the interim, for digital material which is currently being created and collected by the BL, a
secure temporary solution should be found that does not compromise the digital preservation
aims set out above.
Helen Shenton
Deborah Woodyard