Information Technology Reference
In-Depth Information
sources of information which will have been subjected to preservation action such
as format conversion or the addition of Representation Information. A future user
may be required to interact with a number of unfamiliar digital objects in order to
achieve meaningful reuse of data. As a result an archivist will be confronted with
the task of designing an information network which a future data user can navigate
and effectively engage with.
These solutions are also not permanent but have dependencies and associated
risks. These must be monitored and managed by an archive as the realization of
these risks may result in a critical failure to the point where the network can no
longer fulfil the defined objective.
Realization of risk leads to the three different types of failure:
- partial,
- within tolerance
- critical
14.11.2 Partial Failure
The preservation network model below gives an example of a partial failure sce-
nario. We can imagine a scenario in the future where, following a periodic holdings
review it is discovered that the British Atmospheric Data Centre and UNIDATA
have withdrawn support for the NetCDF file format, the Designated Community
has also lost the skill to write programs in C++, FORTRAN 77 and Python. As the
community can still write a program to extract the required parameters the preserva-
tion objective can still be met. However withdrawal of the British Atmospheric Data
support for the NetCDF format may prove to be an appropriate juncture to covert
the file to a different format. Figure 14.11 shows that even if the paths with dashed
arrows fail, there is still a reliable route through the preservation network model
allowing a recovery of the preservation objective.
14.11.2.1 Failure Within Tolerances
The preservation network model section below gives an example scenario of failure
within tolerances. The Ionospheric monitoring group website contain vital prove-
nance and context information relating to Ionosonde raw output files that are the
target of current preservation efforts. For instance Fig. 14.12 highlights that in this
scenario, the loss of being able to render or access the jpeg images from the website
could be tolerated as they do not contain any critical information and hence will not
put achieving the preservation objective in jeopardy.
14.11.3 Critical Failure
The preservation network model section shown below in Fig. 14.13 gives an exam-
ple of critical failure. In this scenario failure of the community's ability to read
Search WWH ::




Custom Search