Planes, trains and cars...

By: David W. Hess (dwhess.delete@this.banishedsouls.org), July 1, 2007 7:40 pm
Room: Moderated Discussions
The type of failures you describe have always struck me as design failures. If any single failure can cause a cascade of other failures, then something is very wrong. For my own designs, I figure that any single open or short should not cause catastrophic failure and where safety or reliability is paramount, systems should be independent in a way that they continue to provide at least a minimum of functionality under adverse conditions.

With cars I am not particularly surprised however because car manufacturers are notoriously cheap. The best defense there is for the end user to eschew as much complexity as possible.

The best failure story I know of involved UL testing of a garage door opener that used a Zilog microcontroller. As part of the certification, any failure had to at a minimum stop garage door movement. As it ends up, the microcontroller's watch dog timer used the crystal clock source (despite the specifications stating otherwise) so crystal failure (not uncommon because of mechanical considerations) defeated it preventing the timeout necessary to detect failure and reset the system to a known state which included halting all movement.

Another failure I am personally familiar with was a TI dual slope integrating analog to digital converter chip set which communicated using sign magnitude. It was specifically specified to only report positive zero but years after being released, it was noticed that the negative scale had an additional one count integral non linearity error because negative zero was a completely valid output taking the place of -1. Not only did TI's testing and verification miss it but their customers missed it also.
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  Core 2 Errata -- problematic or overblown?David Kanter2007/06/27 02:34 PM
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      Core 2 Errata -- problematic or overblown?David Kanter2007/06/27 06:31 PM
      Core 2 Errata -- problematic or overblown?Andi Kleen2007/06/28 12:35 AM
        Core 2 Errata -- problematic or overblown?anonymous2007/06/28 04:16 AM
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        AMD DocumentationDavid Kanter2007/07/01 11:03 AM
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    Core 2 Errata -- problematic or overblown?Groo2007/06/28 01:10 AM
  Core 2 Errata -- problematic or overblown?Linus Torvalds2007/06/27 05:10 PM
    Core 2 Errata -- problematic or overblown?Rob Thorpe2007/06/28 01:11 AM
      Core 2 Errata -- problematic or overblown?JS2007/06/28 04:32 AM
        Core 2 Errata -- problematic or overblown?Rob Thorpe2007/06/28 05:15 AM
          Core 2 Errata -- problematic or overblown?JS2007/06/28 09:55 PM
            Core 2 Errata -- problematic or overblown?Rob Thorpe2007/06/29 12:44 AM
      Core 2 Errata -- problematic or overblown?Linus Torvalds2007/06/28 08:30 AM
        Core 2 Errata -- problematic or overblown?philt2007/06/28 04:28 PM
          Core 2 Errata -- problematic or overblown?Linus Torvalds2007/06/28 07:31 PM
            Core 2 Errata -- problematic or overblown?philt2007/06/29 01:58 AM
              Core 2 Errata -- problematic or overblown?IlleglWpns2007/06/29 02:23 AM
                Core 2 Errata -- problematic or overblown?philt2007/06/29 08:16 PM
              Core 2 Errata -- problematic or overblown?Andi Kleen2007/06/29 04:36 AM
                Core 2 Errata -- problematic or overblown?philt2007/06/29 08:09 PM
                  Core 2 Errata -- problematic or overblown?Brendan2007/06/29 11:04 PM
                    Core 2 Errata -- problematic or overblown?philt2007/06/30 01:52 AM
                      Core 2 Errata -- problematic or overblown?Brendan2007/06/30 09:25 AM
                  Core 2 Errata -- problematic or overblown?Jukka Larja2007/06/29 11:22 PM
                  Core 2 Errata -- problematic or overblown?dan2007/07/05 12:36 PM
              Core 2 Errata -- problematic or overblown?Dean Kent2007/06/29 07:31 AM
                Core 2 Errata -- problematic or overblown?philt2007/06/29 07:57 PM
                  Core 2 Errata -- problematic or overblown?Dean Kent2007/06/29 08:50 PM
                    Core 2 Errata -- problematic or overblown?philt2007/06/30 01:57 AM
                      Core 2 Errata -- problematic or overblown?Dean Kent2007/06/30 05:34 AM
                        Core 2 Errata -- problematic or overblown?philt2007/07/02 03:33 AM
                          Core 2 Errata -- problematic or overblown?Dean Kent2007/07/02 05:36 AM
                            Core 2 Errata -- problematic or overblown?philt2007/07/02 03:02 PM
                              Core 2 Errata -- problematic or overblown?JS2007/07/02 10:02 PM
                      Core 2 Errata -- problematic or overblown?David Kanter2007/07/02 03:20 PM
            Core 2 Errata -- problematic or overblown?Max2007/06/29 11:23 AM
        Core 2 Errata -- problematic or overblown?Rob Thorpe2007/06/29 06:15 AM
          Core 2 Errata -- problematic or overblown?Michael S2007/06/29 06:57 AM
    Core 2 Errata -- problematic or overblown?jozzete2007/06/29 12:54 AM
  Core 2 Errata -- problematic or overblown?Brendan2007/06/28 07:15 PM
    Core 2 Errata -- problematic or overblown?france2007/06/28 10:38 PM
  Core 2 Errata -- problematic or overblown?rwessel2007/06/29 03:20 AM
    Core 2 Errata -- problematic or overblown?jschlossel2007/06/29 10:16 AM
      Core 2 Errata -- problematic or overblown?Dean Kent2007/06/29 10:25 AM
        Core 2 Errata -- problematic or overblown?Howard Chu2007/06/30 05:09 AM
          Core 2 Errata -- problematic or overblown?JS2007/07/02 04:58 AM
      baby and bath waterrels2007/06/30 07:00 AM
      Planes, trains and cars...Anna N.2007/07/01 06:28 PM
        Planes, trains and cars...David W. Hess2007/07/01 07:40 PM
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