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old systems at a breathtaking pace of 2 - 5 years, the threat of technological obsolescence
becomes ever more pressing.
Technological obsolescence
As technical obsolescence accelerates, the "inventories" of obsolete computer technologies
in museums increases rapidly:
The Obsolete Computer Museum <>
The Virtual Museum of Computing <>
Therefore, changes in technology are regarded the greater risk as information will be
rendered inaccessible within a much shorter time period.There is less risk concerning the
technological obsolescence of the storage medium, such as magnetic and optical disks.
"Indeed, technological obsolescence represents a far greater threat to information in digital
form than the inherent physical fragility of many digital media." (Mallinson, 1986)
General preservation strategies
To come to terms with the risks related to technological obsolescence and media
fragility, memory institutions will have to adopt various strategies and methods to keep
digital resources accessible in the future and increase their chance of survival.This include:
Good practice in storing and handling: digital material should be stored in a dust
free environment away from magnetic fields at a stable temperature and relative
humidity; in addition, security issues need to be observed (e.g. that digital media
should be stored in a separate area, with restricted access).
A strategy for retrieval and access: expected retrieval requirements will determine
whether digital information is stored online, near-line, or off-line (e.g. little used
off-line material may be stored on magnetic tape, including compression).
Keeping data about stored sources and tracking the life cycle: keeping vital data
about information management (e.g. preservation, copyrights, use rates).
Cultural heritage in the closet
Archives, libraries and museums are rapidly accumulating storage-intensive digital data
without the management infrastructure to store and protect the data."Most likely", as Jane
Sledge, Information Resource Manager of the National Museum of the American Indian,
USA, noted,"significant collections of thousands of CD-ROMs will end up in the closet.
Only rarely, can museums afford to pay for Storage Area Network solutions to store their
digital collections."
Jane Sledge, DigiCULT Delphi, June 27, 2001
Short- to medium term preservation methods
Refreshing, i.e. periodically copying the data onto a newer carrier of the same type
Transfer: copying data onto a more stable carrier (e.g. transferring data from a floppy
disk to a writeable CD).
Multiple distributed copies ("cloning"): storing identical material in multiple
locations and regularly backing up (in order to protect against loss due to media
failure or human error).
Format migration: converting documents to newer and probably less volatile
standard formats to assist in maintaining access and facilitate later migration.