Page 188 - DLIS001_FOUNDATION_OF_LIBRARY_AND_INFORMATION_SCIENCE

Unit 10: Digital and Virtual Libraries

keeping the bits valid, but refreshing is only effective as long as the media are still current. Notes
The media used to store digital materials become obsolete in anywhere from two to five
years before they are replaced by better technology. Over the long term, materials stored
on older media could be lost because there will no longer have the hardware or software
to read them. Thus, libraries will have to keep moving digital information from storage
medium to storage medium.

The preservation of access to content: This form of preservation involves preserving
access to the content of documents, regardless of their format. While files can be moved
from one physical storage medium to another, what happens when the formats (e.g.,
Adobe Acrobat PDF) containing the information become obsolete? This is a problem
perhaps bigger than that of obsolete storage technologies. One solution is to do data
migration—that is, translate data from one format to another preserving the ability of
users to retrieve and display the information content. However, there are difficulties here
too-data migration is costly, there are as yet no standards for data migration, and distortion
or information loss is inevitably introduced every time data is migrated from format to
format.

Notes The bottom line is that no one really knows how yet how to best migrate digital
information. The Report of the Task Force on Archiving of Digital Information (RLG,
1995) by the US Commission on Preservation and Access and RLG states, “the preservation
community is only beginning to address migration of complex digital objects” and such
migration remains “largely experimental.” Even if there were adequate technology
available today, information will have to be migrated from format to format over many
generations, passing a huge and costly responsibility to those who come after.

The preservation of fixed-media materials through digital technology: This slant on the
issue involves the use of digital technology as a replacement for current preservation
media, such as microforms. Again, there are, as yet, no common standards for the use of
digital media as a preservation medium and it is unclear whether digital media are as yet
up to the task of long-term preservation. Digital preservation standards will be required
to consistently store and share materials preserved digitally.

What can libraries jointly do in a coordinated scheme? They can:
create policies for long-term preservation

ensure that redundant permanent copies are stored at designated institutions
help establish preservation standards to consistently store and share materials preserved
digitally

10.2.4 Building Digital Collections

One of the largest issues in creating digital libraries will be the building of digital collections.
Obviously, for any digital library to be viable, it must eventually have a digital collection with
the critical mass to make it truly useful. There are essentially three methods of building digital
collections:
Digitization, converting paper and other media in existing collections to digital form.
Acquisition of original digital works created by publishers and scholars.

LOVELY PROFESSIONAL UNIVERSITY 183