Information Technology Reference
In-Depth Information
Clearly we can do the simple things like checking whether the bit sequences are
unchanged over time, using one or more standard techniques such as digital digests
[
15
]. However just having the bits is not enough. The demand for the ability for the
object to be “interpreted, understood and used” is broader than that - and of course
it can be tested.
But surely there is another qualification, for is it sensible to demand that
anyone
can “interpret, understand and use” the digital object - say a 4 year old child?
Clearly we need to be more specific. But how can such a group be specified, and
indeed who should choose? This seems a daunting task - who could possibly be in
a position to do that?
The answer that OAIS provides is a subtle one. The people who can should be
able to “interpret, understand and use” the digital object, and whom we can use to
test the success or otherwise of the “preservation”, are defined by the people who
are doing the preservation.
The advantage of this definition is that it leads to something that can
be tested. So if an archive claims “we are preserving this digital object
for astronomers” we can then call in an astronomer to test that claim.
The disadvantage is that the preserver could choose a definition which
makes life easy for him/her - what is to stop that? The answer is
that there is nothing to prevent that but who would rely on such an
archive?
As long as the archive's definition is made clear then the person
depositing the digital objects can decide whether this is acceptable.
The success or failure of the archive in terms of digital objects being
deposited will be determined by the market. Thus in order to suc-
ceed the archive will have to define its Designated Community(ies)
appropriately.
Different archives, holding the same digital object may define their
Designated Communities as being different. This will have implica-
tions for the amount and type of “metadata” which is needed by each
archive.
As we will discuss later on, we need to be able to be a more specific, and we will
see, in
Chap. 7
, how this can be done.
3.2 What “Metadata”, How Much “Metadata”?
One fundamental question to ask is “What 'metadata' do we need?” The problem
with “metadata” is that it is so broad that people tend to have their own limited view.
OAIS provides a more detailed breakdown. The first three broad categories are to
