Page 70 - Building Digital Libraries

Preservation Planning

As you can see, emulation and format migration are complicated issues
for preserving simple individual files consisting of documents and static
images. The process becomes exponentially more difficult as the metadata,
structure, and linkages within the objects become complex, or the objects
are integrally tied to particular platforms.
Whether one chooses to primarily rely on software emulation, file
migration, or a combination of the two really depends on the digital object
itself. Should the digital object and the preservation of the original format
be part of the preservation process, or is digital preservation primarily the
preservation of the digital content and experience? And can an organization
universally agree on one approach, or will the organization use a multiplicity
of approaches based primarily on the preferences of the curator?
At the Ohio State University Libraries (OSUL), curator preference plays
a large role in determining if the original digital object should be preserved,
or if file migration can be used as a primary strategy around digital preser-
vation. Within the OSUL environment, preservation and access are closely
tied together, so while byte-level preservation occurs for all master files, the
master files themselves may have been migrated from other content types.
But this doesn’t always occur. Within the Ohio Congressional Archive, a

FIGURE 4.1
The Ohio Congressional Archive: Multiple Preservation Masters

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