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Re: C Code "sanity checking" tools

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Michael Press <rubrum@pacbell.net> writes:
> In article <877h6mpeb2.fsf@sapphire.mobileactivedefense.com>,
>  Rainer Weikusat <rweikusat@mssgmbh.com> wrote:
>
>> Keith Thompson <kst-u@mib.org> writes:
>> > Rainer Weikusat <rweikusat@mssgmbh.com> writes:
>> >> Keith Thompson <kst-u@mib.org> writes:
>> >>> Rainer Weikusat <rweikusat@mssgmbh.com> writes:
>> >>>> Fritz Wuehler <fritz@spamexpire-201108.rodent.frell.theremailer.net>
>> >>>> writes:
>> >>> [...]
>> >>>>> Yes, Ada language will help with this sort of issue. C isn't safe,
>> >>>>
>> >>>> http://www.di.unito.it/~damiani/ariane5rep.html
>> >>>
>> >>> Are you suggesting that the use of Ada was somehow responsible for the
>> >>> Ariane 5 failure?
>> >>
>> >> To a degree: What was responsible for the Ariane failure was that
>> >> the specification stated that the processer of the functional unit
>> >> in question was to be halted in case of a malfunction: It was assumed
>> >> that 'malfunctions' would only be caused by hardware problems and
>> >> that, in this case, the redundant other functional unit could just
>> >> take over.
>> > [snip]
>> >
>> > As I understand it, the root cause of the failure was that
>> > management decided to use software written for the Ariane 4
>> > without modification. It was written correctly for the Ariane 4;
>> > the kind of out-of-range value that was seen most likely *would*
>> > have indicated a hardware failure.
>> 
>> One of the nice properties of software-induced disasters is that no
>> one is ever responsible for them, except maybe 'some unknown
>> programmer wo left the company a decade ago'. You understood
>> 'correctly' that this is the gut of the failure report: It happened to
>> work on an earlier model. Clearly, by that time, no problem existed!
>
> I get a sense that you did not read the document.

The reason why I wrote 'as far as I remember' was that I did read it
in 2004 or so. And - strange as this may seem - human memory isn't
absolutely reliable. But that's a rather tangential point: A 16-bit
variable overflowed. A runtime check for this caused the CPU to be
halted.

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C Code "sanity checking" tools Martin Crouch <spamspamspam@spaml.com> - 2011-08-08 12:00 +0100
  Re: C Code "sanity checking" tools Richard Kettlewell <rjk@greenend.org.uk> - 2011-08-08 12:09 +0100
    Re: C Code "sanity checking" tools Fritz Wuehler <fritz@spamexpire-201108.rodent.frell.theremailer.net> - 2011-08-09 08:50 +0200
      Re: C Code "sanity checking" tools Måns Rullgård <mans@mansr.com> - 2011-08-09 10:55 +0100
        Re: C Code "sanity checking" tools Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-08-09 14:15 +0100
        Re: C Code "sanity checking" tools Nomen Nescio <nobody@dizum.com> - 2011-08-10 01:58 +0200
        Re: C Code "sanity checking" tools Nomen Nescio <nobody@dizum.com> - 2011-08-10 12:29 +0200
      Re: C Code "sanity checking" tools Rainer Weikusat <rweikusat@mssgmbh.com> - 2011-08-09 14:17 +0100
        Re: C Code "sanity checking" tools Keith Thompson <kst-u@mib.org> - 2011-08-09 09:17 -0700
          Re: C Code "sanity checking" tools Rainer Weikusat <rweikusat@mssgmbh.com> - 2011-08-09 17:36 +0100
            Re: C Code "sanity checking" tools Keith Thompson <kst-u@mib.org> - 2011-08-09 12:19 -0700
              Re: C Code "sanity checking" tools Rainer Weikusat <rweikusat@mssgmbh.com> - 2011-08-09 20:36 +0100
                Re: C Code "sanity checking" tools Michael Press <rubrum@pacbell.net> - 2011-08-09 19:24 -0700
                Re: C Code "sanity checking" tools Rainer Weikusat <rweikusat@mssgmbh.com> - 2011-08-10 10:27 +0100
                Re: C Code "sanity checking" tools Rainer Weikusat <rweikusat@mssgmbh.com> - 2011-08-10 14:01 +0100
                Re: C Code "sanity checking" tools "io_x" <a@b.c.invalid> - 2011-08-13 09:42 +0200
                Re: C Code "sanity checking" tools Keith Thompson <kst-u@mib.org> - 2011-08-13 16:04 -0700
                Re: C Code "sanity checking" tools Rainer Weikusat <rweikusat@mssgmbh.com> - 2011-08-14 19:46 +0100
  Re: C Code "sanity checking" tools Ian Collins <ian-news@hotmail.com> - 2011-08-08 23:12 +1200
    Re: C Code "sanity checking" tools Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-08-08 15:35 +0100
      Re: C Code "sanity checking" tools Martin Crouch <spamspamspam@spaml.com> - 2011-08-08 16:05 +0100
        Re: C Code "sanity checking" tools Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-08-08 22:57 +0100
          Re: C Code "sanity checking" tools Måns Rullgård <mans@mansr.com> - 2011-08-08 23:32 +0100
      Re: C Code "sanity checking" tools Ian Collins <ian-news@hotmail.com> - 2011-08-09 08:03 +1200
        Re: C Code "sanity checking" tools Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-08-08 22:51 +0100
          Re: C Code "sanity checking" tools Ian Collins <ian-news@hotmail.com> - 2011-08-09 10:01 +1200
    Re: C Code "sanity checking" tools jt@toerring.de (Jens Thoms Toerring) - 2011-08-08 22:06 +0000
      Re: C Code "sanity checking" tools Ian Collins <ian-news@hotmail.com> - 2011-08-09 10:18 +1200
        Re: C Code "sanity checking" tools jt@toerring.de (Jens Thoms Toerring) - 2011-08-08 23:25 +0000
  Re: C Code "sanity checking" tools Nobody <nobody@nowhere.com> - 2011-08-08 14:01 +0100
    Re: C Code "sanity checking" tools Måns Rullgård <mans@mansr.com> - 2011-08-08 14:47 +0100
      Re: C Code "sanity checking" tools Martin Crouch <spamspamspam@spaml.com> - 2011-08-08 16:08 +0100
        Re: C Code "sanity checking" tools Marc <marc.glisse@gmail.com> - 2011-08-08 15:39 +0000
      Re: C Code "sanity checking" tools William Ahern <william@wilbur.25thandClement.com> - 2011-08-08 10:20 -0700
      Re: C Code "sanity checking" tools Nobody <nobody@nowhere.com> - 2011-08-09 00:59 +0100
  Re: C Code "sanity checking" tools mathog <dmathog@gmail.com> - 2011-08-08 08:48 -0700

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