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- migration via successive conversions of the files to current formats when the old are outdated (disadvantage: maintenance costs and eventually loosing information with a conversion) and 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


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