...

submission_thesis/CH3_FMEA_criticism/copy.tex

@@ -131,7 +131,17 @@ Although this
 would give a better picture of the failure mode behaviour, it
 is by no means a rigorous approach to tracing errors that may occur in hardware
 through to the top (and therefore ultimately controlling) layer of software.
+%
+With the increasing use of micro-controllers in place of analogue electronics
+for most new designs of electronic product, the poor integration capabilities of FMEA
+are now being seen as deficiencies. 
 
+This apparent then in the dilemma now faced
+by organisations dealing with highly safety critical systems, and having rely on `smart~instruments'
+that they can no longer validate using FMEA.
+Smart instruments are dealt with in the section below.
+Distributed real time systems, which rely on micro-controllers connected in a network
+using a communications protocol, are also impossible to be meaningfully analysed by FMEA.
 
 \subsection{The rise of the smart instrument}
 %% AWE --- Atomic Weapons Establishment have this problem....
@@ -228,10 +238,14 @@ utterly anachronistic in the distributed real time system environment.
    \item Difficult to re-use previous analysis work
    \item Very Difficult to model simultaneous failures.
    \item Software and hardware models are separate.
-   \item Distributed real time systems are very difficult to meaningfully analyse with FMEA.
+   \item Distributed real time systems are very difficult to analyse with FMEA because they typically involve many hardware/software interfaces.
 \end{itemize}
 
-FMEA is no longer fit for purpose!
+Traditional forms of FMEA are no longer % fit for purpose!
+of meaningful use for modern systems incorporating programmatic elements.
+They were designed to analyse simple electro-mechanical systems
+and even the commonplace large integrated analogue circuits (that are physically small), are
+getting to complicated for meaningful analysis using FMEA.
 %
 % 
 % \section{Conclusions on current FMEA Methodologies}