SPEC Kit 325: Digital Preservation · 103
University of Illinois at Urbana-Champaign
IDEALS Digital Preservation Support Policy
PreservationSupportPolicy IDEALS IDEALS Wiki
https://services.ideals.illinois.edu/wiki/bin/view/IDEALS/PreservationSupportPolicy[10/5/11 12:28:45 PM]
ensuring that the bitstream (the 1s and 0s that make up the digital file)
remains exactly the same over time;
assigning a persistent, permanent identifier;
creating preservation metadata;
maintaining onsite and offsite backup copies;
performing regular virus and file corruption checks; and
performing periodic refreshments by copying files to new storage media.
Basic preservation does not ensure that a digital object may be opened by a
computer program or is understandable by a human in the future. For example, in
2006 a faculty member deposits a conference presentation in the Microsoft
PowerPoint format (ppt), a proprietary format. In 2030, a graduate student would like
to view that conference presentation, but the software program - Microsoft
PowerPoint - used to open and read ppt files has been discontinued since 2020.
Old versions of the software program are difficult to find, and, because the ppt file
format had never been publicly documented, there exist no other software programs
to open the file. Even though the original digital object (the conference presentation
in ppt) is still technically viable, it is no longer renderable (able to be opened by a
computer program), and thus not understandable by the graduate student in 2030.
Therefore, for digital objects that meet certain criteria (see below), IDEALS will
strive to preserve not only the viability of the object but also the renderability and the
understandability of the content of the digital object, as well as the original file itself.
In the case of some objects in proprietary formats, this will mean that in addition to
the original digital object, IDEALS will also save a copy of the object transformed
into a file format that is more preservable than the original. For example, the
conference presentation in ppt might also be saved as a pdf/a object (an open,
publicly documented standard). The pdf/a object is a more preservable format than
the ppt format. What may be lost is the full functionality of the original digital object.
For example, the graduate student in our example may not be able to view the
conference presentation as a slide show as the Microsoft PowerPoint software
program allows. However, the content of the conference presentation will be
IDEALS also recognizes that in some cases an access copy of a digital object is
necessary due to the proprietary nature or cost of the software used to render it. For
example, a Microsoft Word document is reliant on the Microsoft Word progam to
render it; IDEALS will also provide a pdf version of the document because pdf
readers are freely and readily available. In some cases, the access copy and the
preservable copy may be the one and the same - a pdf/a version, for example.
Categories of Preservation Support
IDEALS categorizes digital objects into three categories of preservation support.
These categories are defined below. Any format not yet reviewed and evaluated by
IDEALS will receive Category 3 support on deposit. A different category may be
assigned after format review takes place.