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Consideration for CCF Modeling
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For a CCF, there must be (1) a failure involving multiple components and
(2) a common cause that is made “shareable” by the existence of some
coupling mechanism. The shared cause for software must include a common
“active” defect or fault. A CCF can occur when multiple components share
copies of the same software and can be influenced by the same activation scenario.

BAHAMAS works by employing details of the SDLC as inputs to evaluate the
probability of defects remaining within a software, then indicates
that software's failure probability. When software is used
redundantly, BAHAMAS is effectively evaluating the probability of
defects that exist between redundant software components. For the
purpose of supporting CCF assessments, BAHAMAS employs the common or
shared attributes found between the software of a digital instrumentation and control system. The
shared SDLC details act as input that enables BAHAMAS to predict the probability
of shared defects and ultimately the probability of shared failures or
CCFs.