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kt maltid skrivning mn nagan harker hela tiden

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Robin P. Clark 2012-11-26 14:02:57 +00:00
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commit 086361edff
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submission_thesis/CH5_Examples/context_calltree.dia
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submission_thesis/CH5_Examples/context_diagram2_PID.dia
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submission_thesis/CH5_Examples/context_software.dia
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submission_thesis/CH5_Examples/software.tex
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@ -84,7 +84,7 @@ and traceable way. Each function is subject to pre-conditions (constraints on it
post-conditions (constraints on its outputs) and function wide invariants (rules). post-conditions (constraints on its outputs) and function wide invariants (rules).
\paragraph{Mapping contract `pre-condition' violations to failure modes.} \paragraph{Mapping contract `pre-condition' violations to component failure modes.}
A precondition, or requirement for a contract software function A precondition, or requirement for a contract software function
defines the correct ranges of input conditions for the function defines the correct ranges of input conditions for the function
@ -92,12 +92,22 @@ to operate successfully.
% %
% C Garret said this was unclear so I have added the following two sentences. % C Garret said this was unclear so I have added the following two sentences.
% %
If we consider a software function to be a {\fg} in the FMMD sense, %If we consider a software function to be a {\fg} in the FMMD sense, i.e.
we see that it is can be considered to be a collection of functions that it We can consider a software function to be
calls and variables/inputs that it uses. a collection of code, functions called and values/variables used.
In this way it is similar to an electronic circuit, which is a collection
of components connected in a specific way.
In this analogy the connections are the code, and the functions and variables are the components.
% %
If we consider these functions and inputs to be its components, %EHHRHHHUH
any erroneous behaviour from them can be considered to be a component failure mode. %EERRGHHH COUGH COUGH
%
%
If we consider the
calls and variables/inputs to be components of a function,
%
any erroneous behaviour from them has the same effect as component failure mode
on an electronic {\fg}. %HHmmm HHHHMMMM XXXXXX gora den har nar dets finns into nagon some harker hela tiden
% %
For a software function, a violation of a pre-condition is For a software function, a violation of a pre-condition is
in effect a failure mode of `one of its components'. in effect a failure mode of `one of its components'.