Information Technology Reference
In-Depth Information
Semantic Representation Information, and then write an appropriate applica-
tion. This would no doubt be harder, but at least one would not have to guess
at what information the digital object holds.
Some of these options are trivial - which would be very convenient for the user.
However if a trivial option is not available then at least the other options are possi-
ble - the information can be extracted with considerable certainty and used for other
purposes.
9.2 Use of Existing Software
Option (A) above is an example of using existing software - albeit probably old
software. Amore interesting example is the case where one wants to use information
from this digital object with one's current favourite software. This may be because of
the additional functionality which that favourite software provides. The additional
functionality could include being able to combine that data with other data more
easily. Again one can imagine that this other software may be associated with (e.g.
in the Representation Information Network of) other archived data or it may be more
modern software - the argument applies equally.
Once again one can imagine several ways of doing this and these are described
next.
9.2.1 Migration/Transformation
Migration - or more precisely Transformation (using OAIS terminology) - involves
changing the bit sequences from the original to something else. Following the recent
revision of OAIS one can recognise that if this transformation is reversible then one
can be confident that no information has been lost. On the other hand non-reversible
transformations probably have lost information and someone must take respon-
sibility to confirm that the transformation adequately maintains the “important”
information. This is discussed in much more detail in
Sect. 13.6
.
For those with an eye for recursion, the ways in which the trans-
formation could be carried out are special cases of this sub-section,
namely using a single digital object. For example one can use exist-
ing software, the subject of this sub-section, if there is software
which can take in the original bit sequences in order to perform the
transformation.
One could alternatively use a data description language (DDL) description to
extract values from the original and write them out as the new bit sequences. This
could be done using generic applications as illustrated in Fig.
9.3
or else could be
hand-crafted.
The transformation chosen will of course be one which produces something
which can be used by the software which has been chosen to deal with the
