Information Technology Reference
In-Depth Information
several different documentation files (one for speakers installation, one for micro-
phones, one for general setup and installation
...
). All these documentation files can
be grouped together in a single PDF file.
22.3.1 Challenge 1: Preserving the Whole Set of Objects, with Its
Logical Meaning
The first important challenge is to preserve the logical relationship between all these
objects. That logical relationship is one of the most important part of the challenge,
since the preservation strategy applicable to each element can be dependent on the
logical relationship an element has with the whole set.
An example of this is a set of audio files used to store parameters. During our
analysis of the content of the repository, some problems occurred, one of the most
glaring being the case of audio files used to store numerical parameters: instead of
storing audio, some audio files are used to store numerical parameters that serve
as input to real-time processes in order to change their behaviour. This behaviour
seems to be very frequent, since audio files are well known to the community, and
their use is thus facilitated.
Due to this fact, migration techniques that are applicable to audio files cannot
be applied to these specific parameter files (the reason of this is very evident to any
member of the community). Thus, the logical relationship to the whole set of objects
has to be maintained in order to achieve preservation.
22.3.2 Challenge 2: Preserving the Processes, and Achieving
Authenticity Throughout Migrations
As explained in detail below, the second important challenge is to preserve the real-
time process (the so-called “patch”). The obsolescence of the environments able
to execute the real-time process is so rapid that processes need to be migrated
approximately every 5 years. Moreover, there is a need to achieve a certain
form of authenticity throughout the successive migrations that cannot be evi-
dently based on simple provenance and Fixity Information, as defined by the OAIS
model.
22.4 Preserving the Real-Time Processes
Briefly speaking, the Representation Information for our real-time processes is:
Structure: the structure is a block-diagram flow structure.
Semantics: semantic of each element is (most of the time) already existing in
documentation.
A simple example, showing the structure of a (very simple) process, that provides
the structure and the semantics of one of these elements is shown in Fig. 22.2 .
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