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=0.2 required=5.0 tests=BAYES_00,INVALID_MSGID, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 107079,eca28648989efca9 X-Google-Attributes: gid107079,public X-Google-Thread: 101deb,885dab3998d28a4 X-Google-Attributes: gid101deb,public X-Google-Thread: f74ae,eca28648989efca9 X-Google-Attributes: gidf74ae,public X-Google-Thread: 103376,885dab3998d28a4 X-Google-Attributes: gid103376,public From: molagnon@ifremer.fr (Michel OLAGNON) Subject: Re: Ariane 5 failure Date: 1996/09/25 Message-ID: <52amke$m9e@ys.ifremer.fr>#1/1 X-Deja-AN: 185207568 distribution: inet references: <52a572$9kk@goanna.cs.rmit.edu.au> organization: Ifremer reply-to: molagnon@ifremer.fr newsgroups: sci.astro,sci.math.num-analysis,comp.lang.pl1,comp.lang.ada Date: 1996-09-25T00:00:00+00:00 List-Id: In article <52a572$9kk@goanna.cs.rmit.edu.au>, rav@goanna.cs.rmit.edu.au (@@ robin) writes: >[reports of Ariane and STS-2 bugs deleted] > > >In both cases, the programing error could have been detected >with a simple test, but in both cases, no test was included. > >One would have thought that having had one failure (at least) >for integer out-of-range, that the implementors of the software >for Ariane 5 would have been extra careful in ensuring that >all data conversions were within range -- since any kind >of interrupt would result in destruction of the spacecraft. > May be the main reason for the lack of testing and care was that the conversion exception could only occur after lift off, and that that particular piece of program was of no use after lift off. It was only kept running for 50 s in order to speed up countdown restart in case of an interruption between H0-9 and H0-5. Conclusion: Never compute values that are of no use when you can avoid it ! >There's a case for a review of the programming language used. Michel -- | Michel OLAGNON email : Michel.Olagnon@ifremer.fr| | IFREMER: Institut Francais de Recherches pour l'Exploitation de la Mer|