Information Technology Reference
In-Depth Information
Potential points of failure
Potential solutions
Failure of any chain of preservation may be
imagined as involving changes in, or
non-maintainability of, essential hardware,
software or support environment.
Additionally the human methodology
established for preservation may not be
followed (sudden changes of a whole team
of people, etc.)
One of the recognised techniques of isolating
dependencies on hardware, software and
environment is virtualisation. By this is meant
the technique of identifying important, abstract,
interfaces/processes which can be implemented
on top of concrete implementations which are
available at any particular time in the future
OAIS stresses the importance of taking into
account the changes in the knowledge base
of the designated community. This may not
be done adequately
Changes in Knowledge Base can only be truly
solved by the community itself, but procedures
can be proposed which help to ensure that gaps
in understandability are at least recognised and
the information requested from the community
before it is entirely lost
Additionally one may have a loss in the chain
of evidence and lack of certainty of
provenance or authenticity
Provenance and authenticity is, in part at least,
dependent on social and information policy
concerns, process documentation, and other
aspects which cannot have a purely technical
solution. However some tools can be made
available to ameliorate the risks of security
breaches. Systems security and data integrity
are only two aspects of provenance and
authenticity, and we should be careful not to
assume that tools for these problems will
provide solutions to larger problems
Encodings used to establish lack of tampering
and currently considered unbreakable, may
eventually be broken using increasingly
powerful processors or sophistication of
attack
Constant vigilance about security of encodings
and a preparedness to apply more secure
encoding
The custodian of the data, an organisation or
project, no matter how well established,
may, at some point in the future, cease to
exist
Custodianship should always be regarded as a
temporary trust and techniques are needed to
allow a smooth handing over of holdings from
one link in the chain of preservation to the next
Even if the organisation exists, the
mechanisms to identify the location of data,
for example a DNS entry pointing to a host
machine, may no longer be resolvable
The provision of a definitive system of persistent
actionable identifiers which spreads the risk of
the deterioration of identifier systems must be
proposed
Mandating the continued use of specific
systems or formats is one possible way to
try to ensure preservation. For example we
might try to mandate all images to be JPEG,
all documents to be PDF/A, and all science
data to be kept as XML files, or demand that
a specific ontology be adopted. Even if we
were to be successful for a limited time, the
one thing we can be sure of is that things
would change and the mandates would fail
Given the constantly changing world we need a
system which does not force a specific way of
doing things but instead we should be able to
allow anything to be accommodated. For
example we cannot mandate a particular way
of producing representation information or
provenance. While it might have some
advantages in terms of interoperability in the
short term, in the long term we would be
locked into a dead-end. However this should
not prevent us from advising on best practise
