[SystemSafety] Degraded software performance [diverged from Fault, Failure and Reliability Again]

[Peter Bernard Ladkin]

Michael,

On 2015-03-05 13:29 , Michael J. Pont wrote:
> I believe that there are many people on this list who take the view that
> concept of "software reliability" (as used in this appendix) is flawed and
> unhelpful.  Replacing this with another appendix that is based on the same
> concept does not seem to me to be a huge step forward.

There are more people on this list with a good publications record in the statistical evaluation of
software than there are people who have recently expressed an opinion that the entire approach is
flawed.

Not that numbers say anything, of course. Except in committee votes.

What is most obvious is that those denigrating statistical evaluation are almost exclusively
aerospace. The clientele of IEC 61508 excludes aerospace and medical devices. I wonder, though, how
aerospace, at least civil aerospace, can lecture anyone else on coherence when it can't align its
practice with its written requirements?

It is almost equally obvious - at least to me - that almost none of the commentary addressed
arguments which actually appear in the papers.

PBL

Prof. Peter Bernard Ladkin, Faculty of Technology, University of Bielefeld, 33594 Bielefeld, Germany
Je suis Charlie
Tel+msg +49 (0)521 880 7319  www.rvs.uni-bielefeld.de