From: MRE <Marc.Enzmann@web.de>
Subject: Re: OT?: AF 447 and avionics software
Date: Sun, 7 Jun 2009 01:33:50 -0700 (PDT)
Date: 2009-06-07T01:33:50-07:00 [thread overview]
Message-ID: <4d622e52-5fd7-401f-a6f9-b74d1bfd307e@x5g2000yqk.googlegroups.com> (raw)
In-Reply-To: 7b4aed55-0885-4513-8db7-c42879e5f341@o14g2000vbo.googlegroups.com
On 6 Jun., 12:38, sjw <simon.j.wri...@mac.com> wrote:
> On Jun 5, 8:22 am, MRE <Marc.Enzm...@web.de> wrote:
>
> > The rocket scientist that came to this brilliant conclusion seems to
> > be a real expert in the field of complexity theory.
> > Thing is: even if you use analog electronics 50's style you can not be
> > sure that you have checked all possible combinations of events.
>
> I think the difference is that analog systems tend to break in much
> less complex ways than digital ones. A run-time exception is likely to
> result in catastrophic and unpredictable misbehaviours. Who would have
> thought that buffer overflows could lead to botnets overloading the
> net with spam?
The issue in flight-systems is: we are using digital systems to
control
analog behaviour. Therefore the level of complexity (is hopefully)
not
determined by the solution but by the problem.
Why would you think that a faulty OpAmp in a complex control circuit
has
less than unpredictable behaviour than a crash in a software system?
The problem is definitely NOT digital flight controls, whatever the
self-proclaimed pundits state. It has been universally acknowledged
wisdom in
the aerospace industry, that accidents / incidents rarely occur due to
one
single failure but due to a combination of problems. If you look at
the
statement quoted here http://www.time.com/time/world/article/0,8599,1902421,00.html
this is however stated to be true only for digital systems. And
that's
rubbish.
Regards,
Marc
next prev parent reply other threads:[~2009-06-07 8:33 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-04 9:29 OT?: AF 447 and avionics software Alex R. Mosteo
2009-06-04 11:02 ` Martin
2009-06-04 18:20 ` roderick.chapman
2009-06-06 17:34 ` Martin
2009-06-04 11:58 ` Egil Høvik
2009-06-04 13:25 ` Alex R. Mosteo
2009-06-04 19:02 ` Olivier Scalbert
2009-06-04 20:17 ` Matteo Bordin
2009-06-05 7:22 ` MRE
2009-06-06 10:38 ` sjw
2009-06-06 10:52 ` Dmitry A. Kazakov
2009-06-07 11:16 ` Florian Weimer
2009-06-07 13:19 ` Dmitry A. Kazakov
2009-06-10 6:11 ` MRE
2009-06-10 7:36 ` Dmitry A. Kazakov
2009-06-07 8:33 ` MRE [this message]
2009-06-05 9:22 ` Ludovic Brenta
2009-06-05 20:35 ` Tim Rowe
2009-06-09 21:06 ` Olivier Scalbert
2009-06-09 22:14 ` Martin
2009-06-10 6:12 ` MRE
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