From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM autolearn=ham autolearn_force=no version=3.4.4 X-Google-Thread: 103376,ac9405996d0dcb7f X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!postnews.google.com!not-for-mail From: snarflemike@yahoo.com (Mike Silva) Newsgroups: comp.lang.ada Subject: Re: Would You Fly an Airplane with a Linux-Based Control System? Date: 26 Nov 2004 13:09:54 -0800 Organization: http://groups.google.com Message-ID: <20619edc.0411261309.220c8ab8@posting.google.com> References: <20619edc.0411251028.3e249bf3@posting.google.com> NNTP-Posting-Host: 67.8.58.78 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Trace: posting.google.com 1101503394 25977 127.0.0.1 (26 Nov 2004 21:09:54 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Fri, 26 Nov 2004 21:09:54 +0000 (UTC) Xref: g2news1.google.com comp.lang.ada:6525 Date: 2004-11-26T13:09:54-08:00 List-Id: Marius Amado Alves wrote in message news:... > Alexander E. Kopilovich wrote: > >... > > - The on-board software detects that one of the accelerometers is out of > > range (actually, there was FPU exception generated when float-to-integer > > conversion exceeded the capacity of the integer), this was interpreted as > > hardware error and caused the backup processor to take over;... > > > > Do you agree that this addition is enough there? > > No. This whole talk of hardware-generated exception sounds like "FUD". > Namely, it sounds like your trying to blame the hardware. The cause was > a SOFTWARE enginering error. Yes, a BUG. In the Ada software. And > because it's connected to exceptions, the hypothesis that if the thing > had been done in an exceptionless language like C the effect might have > been different. And yes, maybe less bad. And none of the explanations > I've seen so far (here, in books, and in the Internet) disprove this > hypothesis. Even accepting your assertion that your hypothesis has not been disproven, what conclusion do you draw? That deliberately ignoring out-of-range data (not throwing it away, just ignoring it) will generally lead to safer systems than dealing with out-of-range data in some pre-determined way that may not always be the right choice (especially if the system is mis-used in a manner so that out-of-range data is suddenly legal)? What, again, is your conclusion?