| |
ELAG
2001 - Integrating Heterogeneous Resources
- Prague, 6-8 June 2001
WORKSHOP #6
LONG-TIME ARCHIVING: PRESERVING THE ACCESS TO
(LICENSED) ELECTRONIC DOCUMENTS
In Europe the definition for digital
preservation or digital archiving mostly used is the one in the UK CEDAR
project:
‘Storage, maintenance, and access
to a digital object over the long term, usually as a consequence of applying
one or more preservation strategies’
whereby a ‘digital object’ in this sense, is
a ‘any resource that can be stored or manipulated by a computer and can
be applied to digitised and born-digital material.
We distinct (with thanks to the CMC
in Mikkeli, Finland)
- Preservation
= high artifactual value –
permanently retained.
- Conservation
= importance in intellectual content;
highly used copy
= little-used, brittle. Microfilm
- Digitisation
= high artifactual value – digitisation:
high quality access
= high demand – digitisation for access,
microfilm for preservation
= small demand – microfilm
- hybrid projects
= digital files complemented by
analog media
The inceasing amount of digital information
has a serious flaw: there are sofar no available techniques for ensuring
that digital information will remain accessible, readable and usable in
the future, unless we find ways to ensure the longevity of digital artifacts,
considerable amounts of valuable information may be lost forever.
The discussion about solutions for this
problem (migration/conversion or emulation)
has been part of the NEDLIB project and
the IBM Digital Libraries projects in the Netherlands and the UK will look
at the 3 approaches for digital preservation.
- the technological museum of old
computers and software (not many supporters in Europe),
- migration via successive conversions of
the files to current formats when the old are outdated (disadvantage: maintenance
costs and eventually loosing information with a conversion) and
- emulation of the old programmes or at least
its reading part via reading of old files by writing new software in the
current computer environment.
Cultural heritage authorities in Europe seem
to tend to a combination of emulation and migration. More sophisticated,
but also more expensive.
The term refreshing, the regular transfer
of data from a medium with a threat of detoriation to a ‘newer’ medium,
is less used in Europe, as ‘refreshing’ is considered to be a less sophisticated
form of migration.
As we are dealing with a variety of born-digital
or (to be) digitised documents or a special form of these documents or
resources called publications, it makes sense to distinct the following
categories of documents:
- off-line printed (paper,
microfilm)
- off-line electronic or discrete physical
digital media, such as diskettes, tapes, CD-ROM, DVD
- e-books (online distributed, but used
offline)
- hybrid electronic documents (discrete
documents which contains links to online material) and
- online documents available on the Internet
or via proprietary networks.
Online documents can be further characterized
by their ‘fixity’
- static documents (form and content
is recognised as substantially fixed throughout at the point of publication
and throughout its lifecycle)
- cumulative resources, whereby ‘fixed’
content is added to throughout its lifecycle (broadly the equivalent of
a serials publication) and
- dynamic resources, those whose form and/or
content change continuously or ‘dynamically’ throughout its lifecycle (see
the par. about Web-archiving).
All objects in a digital application
– for access, storage or long-term preservation – should have a well choosen
policy as part of integrated production process in stead of execution in
splendid isolation:
- be in an approved format
- have a unique indentifier (URN)
- have metadata registered in a database
- have to include metadata
- meet quality standards
- meet migration requirements, eventually
emulation requirements
- pre-defined user services
Most of these requirements/functions are covered
by the OAIS reference model.
Despite (all) the attention for digital archiving
and preservation the role of microfilm is very robust and far from over
and many European projects are hybrid in the sense of a combination of
digital and analog.
Prepared by Johan van Halm <JohanvanHalm@cs.com>
Ammersfoort, 18 April 2001 |