Re: [SystemSafety] Fault, Failure and Reliability Again (short)

From: José Faria < >
Date: Wed, 4 Mar 2015 10:48:20 +0000


Peter,

Just a note on your comment, "*it is surely a matter of engineering reasonsibility due diligence that these engineers get themselves up to date on the concepts the experts, the computer scientists, use to talk about their subject matter*":

The two key standards in aerospace for System and Safety assessment are ARP4754A (Guidelines For Development Of Civil Aircraft and Systems) and ARP4761 (Guidelines and Methods for Conducting the Safety Assessment Process on Civil Airborne Systems and Equipment), and the terminology used in both of these standards is _not_ consistent with Laprie's taxonomy. It's only fair that engineers working in aerospace use the terminology of the regulations they are to comply with.

ARP475A was released in 2010. ARP4761 is already from the 90's and is under revision, but I am not aware of the process status, and neither if significant terminology changes are under discussion. Perhaps someone in this forum can provide further insights.

Thanks,
Jose'

On Wed, Mar 4, 2015 at 8:57 AM, Peter Bernard Ladkin < ladkin_at_xxxxxx

> Folks,
>
> a partial reply to Nick is at
>
> http://www.abnormaldistribution.org/2015/03/04/fault-failure-reliability-definitions/
>
> John Knight said he uses the Laprie taxonomy (as the 2004 paper referenced
> by Örjan yesterday is
> known) in his book, precisely in order to keep straight on such matters as
> we have been discussing.
> I took John's suggestion in my blog post. Software failure, software
> fault, software error, and
> software reliability are given a clear meaning in the Laprie taxonomy,
> although it is not determined
> how one may measure software reliability.
>
> Since the Laprie taxonomy is the result of decades of deliberate in IFIP
> WG 10.4 which first
> resulted in a book, before this paper, it should by no means be dismissed
> lightly.
>
> This decisively contradicts Nick's proposal that
>
> On 2015-03-03 22:50 , Nick Tudor wrote:
> > .....the software does not fail, the system does. It therefore makes no
> sense to talk about
> > reliability of software
>
> Nick has suggested privately that this view is prevalent in aerospace, and
> I am informed indirectly
> that it is also prevalent in some areas of the nuclear industry. If so, it
> is surely a matter of
> engineering reasonsibility due diligence that these engineers get
> themselves up to date on the
> concepts the experts, the computer scientists, use to talk about their
> subject matter.
>
> 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
>
>
>
>
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> systemsafety_at_xxxxxx >

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--
*José Miguel Faria*
*Educed *- Engineering made better
t: +351 913000266
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e: jmf_at_xxxxxx



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