SLAMorris Final Thesis After Corrections.pdf - Cranfield University

data may be affected by the behaviour of the user [Casey, 2006]. Not every
user is reliable in their actions; they may not act as expected, for example a
user may use a log on name other than their own to provide the appearance of
another user committing a set of tasks. Since the user is often an unknown and
unseen factor in the equation it can often add several degrees of separation
between the analyst and the real results of an analysis. An analyst needs to
learn to account for the uncertainty the user brings to an analysis and qualify
the results accordingly. However Casey [2006] has shown the negligibility of the
user’s actions; as it is possible for an analyst to analyse the available evidence
and present the available information regardless of the user’s behaviour.
Whilst data may be corrupted through purposeful actions, a degree of
accidental destruction of the data is often unavoidable; for example, employees
who are inadequately trained may input inaccurate information or delete the
wrong files [Ozdemir, 2002]. Such accidental destruction can be a significant
problem for organisations, and therefore employees may not voluntarily report
such behaviour, causing further reliability problems for the data and the
organisation. Possible ways of managing this are discussed by Ozdemir [2002],
however human error will always play a role in the corruption of data; any
system for mitigation is unlikely to completely remove the problem. Since the
user has no active involvement with the thumbnail cache, except for altering the
original file, user error is an unlikely cause of corruption of the data. However
the individuals who create software which reads and writes to the thumbnail
cache may cause the corruption of data within the cache, for example, by not
providing the information required by the cache in the correct format.
Hard drive failures can be caused by both physical and operational errors.
When a physical sector is defined as faulty it is not possible to read and write to
it without specialist equipment; the computer can generally identify failures and
keep a record [Elerath, 2007]. Operation failures are generally not fixed which
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