Re: Continue with learning C

From	David Brown <david.brown@hesbynett.no>
Newsgroups	comp.lang.c
Subject	Re: Continue with learning C
Date	2016-09-19 13:29 +0200
Organization	A noiseless patient Spider
Message-ID	<nroi5v$sfd$1@dont-email.me> (permalink)
References	(9 earlier) <nrmcav$p43$1@dont-email.me> <nrmrdp$gbl$1@dont-email.me> <b0a0a0f1-1f06-44ec-9614-e44b5ef011b9@googlegroups.com> <nro66t$nhe$1@dont-email.me> <nrobmb$82t$1@dont-email.me>

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On 19/09/16 11:38, BartC wrote:
> On 19/09/2016 09:04, David Brown wrote:
> 
>> (The space shuttle folks skimped on this by using multiple identical
>> cpus, and, AFAIK, the same software on each.)
> 
> From "Into the Black" by Rowland White:
> 
> "Still not entirely happy to trust in the machines, NASA also included a
> fifth, back-up computer, programmed not by IBM but separately by
> Rockwell. If a fatal software bug, endemic to the work done by IBM,
> somehow slipped through the net, the uncontaminated Rockwell machine
> would bring the Shuttle home."
> 

So they got that one right!

I still think it was a poor decision to use identical processors in the
first four systems - you want to maximise the difference between them.

Modern safety-critical microcontrollers are often built with two
processor cores, operating in lock-step from the same inputs and
software, with detection of inconsistent outputs.  In some of these
devices, the two cores are the same design but physically oriented in
different directions (one core is upside down an 90° rotated with
respect to the other).  In others, the layout is completely independent
from the same hardware source code - all in the name of keeping the
logical operation identical, but the susceptibility to external
influences as independent as possible.

Thread

Continue with learning C Alla _ <modelling.data@gmail.com> - 2016-09-15 05:11 -0700
  Re: Continue with learning C "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-09-15 05:29 -0700
  Re: Continue with learning C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-15 15:01 +0100
  Re: Continue with learning C Richard Heathfield <rjh@cpax.org.uk> - 2016-09-15 15:32 +0100
    Re: Continue with learning C Alla _ <modelling.data@gmail.com> - 2016-09-15 08:10 -0700
    Re: Continue with learning C luser droog <luser.droog@gmail.com> - 2016-09-15 12:06 -0700
      Re: Continue with learning C Richard Heathfield <rjh@cpax.org.uk> - 2016-09-15 21:38 +0100
        Re: Continue with learning C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-16 21:02 -0700
          Re: Continue with learning C "Osmium" <r124c4u102@comcast.net> - 2016-09-17 08:03 -0500
          Re: Continue with learning C Richard Heathfield <rjh@cpax.org.uk> - 2016-09-17 22:38 +0100
            Re: Continue with learning C "James R. Kuyper" <jameskuyper@verizon.net> - 2016-09-17 18:14 -0400
              Re: Continue with learning C raltbos@xs4all.nl (Richard Bos) - 2016-09-18 10:47 +0000
              Re: Continue with learning C Alla _ <modelling.data@gmail.com> - 2016-09-19 01:25 -0700
                Re: Continue with learning C Ian Collins <ian-news@hotmail.com> - 2016-09-19 20:51 +1200
                Re: Continue with learning C James Kuyper <jameskuyper@verizon.net> - 2016-09-19 09:49 -0400
                Re: Continue with learning C Richard Heathfield <rjh@cpax.org.uk> - 2016-09-19 15:15 +0100
                Re: Continue with learning C Keith Thompson <kst-u@mib.org> - 2016-09-19 11:39 -0700
                Re: Continue with learning C Reinhardt Behm <rbehm@hushmail.com> - 2016-09-20 09:55 +0800
                Re: Continue with learning C David Brown <david.brown@hesbynett.no> - 2016-09-20 08:50 +0200
                Re: Continue with learning C Reinhardt Behm <rbehm@hushmail.com> - 2016-09-20 18:04 +0800
                Re: Continue with learning C David Brown <david.brown@hesbynett.no> - 2016-09-20 13:25 +0200
                Re: Continue with learning C Reinhardt Behm <rbehm@hushmail.com> - 2016-09-20 20:18 +0800
                Re: Continue with learning C David Brown <david.brown@hesbynett.no> - 2016-09-20 15:25 +0200
                Re: Continue with learning C Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-20 08:45 -0400
                Re: Continue with learning C Reinhardt Behm <rbehm@hushmail.com> - 2016-09-20 22:05 +0800
                Re: Continue with learning C Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-20 10:56 -0400
                Re: Continue with learning C Rosario19 <Ros@invalid.invalid> - 2016-09-19 18:55 +0200
                Re: Continue with learning C Anton Shepelev <anton.txt@gmail.com> - 2016-09-25 01:08 +0300
            Re: Continue with learning C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-17 17:08 -0700
              Re: Continue with learning C Richard Heathfield <rjh@cpax.org.uk> - 2016-09-18 01:11 +0100
                Re: Continue with learning C Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-17 21:32 -0400
                Re: Continue with learning C David Brown <david.brown@hesbynett.no> - 2016-09-18 16:27 +0200
                Re: Continue with learning C Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-18 16:08 -0400
                Re: Continue with learning C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-18 07:30 -0700
                Re: Continue with learning C Jerry Stuckle <jstucklex@attglobal.net> - 2016-09-18 16:07 -0400
                Re: Continue with learning C David Brown <david.brown@hesbynett.no> - 2016-09-18 16:38 +0200
                Re: Continue with learning C BartC <bc@freeuk.com> - 2016-09-18 16:37 +0100
                Re: Continue with learning C Reinhardt Behm <rbehm@hushmail.com> - 2016-09-18 23:54 +0800
                Re: Continue with learning C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-18 16:56 -0700
                Re: Continue with learning C Richard Heathfield <rjh@cpax.org.uk> - 2016-09-18 17:05 +0100
                Re: Continue with learning C "James R. Kuyper" <jameskuyper@verizon.net> - 2016-09-18 12:28 -0400
                Re: Continue with learning C Malcolm McLean <malcolm.mclean5@btinternet.com> - 2016-09-18 17:00 -0700
                Re: Continue with learning C Alla _ <modelling.data@gmail.com> - 2016-09-19 01:40 -0700
                Re: Continue with learning C "Osmium" <r124c4u102@comcast.net> - 2016-09-19 08:55 -0500
                Re: Continue with learning C "Osmium" <r124c4u102@comcast.net> - 2016-09-18 11:31 -0500
                Re: Continue with learning C Ian Collins <ian-news@hotmail.com> - 2016-09-19 07:25 +1200
                Re: Continue with learning C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-18 20:36 +0100
                Re: Continue with learning C "James R. Kuyper" <jameskuyper@verizon.net> - 2016-09-18 15:45 -0400
                Re: Continue with learning C Rosario19 <Ros@invalid.invalid> - 2016-09-19 18:58 +0200
                Re: Continue with learning C "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-09-18 09:55 -0700
                Re: Continue with learning C "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-09-18 10:12 -0700
                Re: Continue with learning C luser droog <luser.droog@gmail.com> - 2016-09-18 13:11 -0700
                Re: Continue with learning C David Brown <david.brown@hesbynett.no> - 2016-09-18 21:54 +0200
                Re: Continue with learning C supercat@casperkitty.com - 2016-09-18 15:58 -0700
                Re: Continue with learning C Richard Heathfield <rjh@cpax.org.uk> - 2016-09-19 07:09 +0100
                Re: Continue with learning C David Brown <david.brown@hesbynett.no> - 2016-09-19 10:04 +0200
                Re: Continue with learning C BartC <bc@freeuk.com> - 2016-09-19 10:38 +0100
                Re: Continue with learning C David Brown <david.brown@hesbynett.no> - 2016-09-19 13:29 +0200
                Re: Continue with learning C supercat@casperkitty.com - 2016-09-19 08:04 -0700
                Re: Continue with learning C Reinhardt Behm <rbehm@hushmail.com> - 2016-09-20 09:33 +0800
                Re: Continue with learning C supercat@casperkitty.com - 2016-09-19 20:47 -0700
                Re: Continue with learning C David Brown <david.brown@hesbynett.no> - 2016-09-20 09:00 +0200
                Re: Continue with learning C Reinhardt Behm <rbehm@hushmail.com> - 2016-09-20 17:59 +0800
                Re: Continue with learning C Ike Naar <ike@iceland.freeshell.org> - 2016-09-20 17:24 +0000
                Re: Continue with learning C David Brown <david.brown@hesbynett.no> - 2016-09-20 08:57 +0200
                Re: Continue with learning C supercat@casperkitty.com - 2016-09-20 10:53 -0700
                Re: Continue with learning C Reinhardt Behm <rbehm@hushmail.com> - 2016-09-19 13:19 +0800
                Re: Continue with learning C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-09-19 01:30 +0100
      Re: Continue with learning C Alla _ <modelling.data@gmail.com> - 2016-09-19 01:15 -0700
  Re: Continue with learning C Barry Schwarz <schwarzb@dqel.com> - 2016-09-15 12:38 -0700
  Re: Continue with learning C fir <profesor.fir@gmail.com> - 2016-09-21 11:42 -0700
    Re: Continue with learning C fir <profesor.fir@gmail.com> - 2016-09-21 12:40 -0700
      Re: Continue with learning C fir <profesor.fir@gmail.com> - 2016-09-21 12:49 -0700
      Re: Continue with learning C fir <profesor.fir@gmail.com> - 2016-09-23 14:47 -0700
        Re: Continue with learning C fir <profesor.fir@gmail.com> - 2016-09-23 14:59 -0700

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