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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: fac41,a48e5b99425d742a X-Google-Attributes: gidfac41,public X-Google-Thread: 1108a1,5da92b52f6784b63 X-Google-Attributes: gid1108a1,public X-Google-Thread: f43e6,a48e5b99425d742a X-Google-Attributes: gidf43e6,public X-Google-Thread: 103376,a48e5b99425d742a X-Google-Attributes: gid103376,public From: Ken Garlington Subject: Re: Please do not start a language war (was Re: Papers on the Ariane-5 crash and Design by Contract Date: 1997/03/21 Message-ID: <3332C049.2A0F@lmtas.lmco.com>#1/1 X-Deja-AN: 227290124 References: <332B5495.167EB0E7@eiffel.com> <5giu3p$beb$1@news.irisa.fr> <332ED8AB.21E7@lmtas.lmco.com> <5go8nk$ngf$1@news.irisa.fr> Organization: Lockheed Martin Tactical Aircraft Systems Newsgroups: comp.lang.eiffel,comp.object,comp.software-eng,comp.lang.ada Date: 1997-03-21T00:00:00+00:00 List-Id: Jean-Marc Jezequel wrote: > > In article <332ED8AB.21E7@lmtas.lmco.com>, Ken Garlington writes: > > > 2. No one ran a full integration test with realistic flight data, > >which would have > > alerted them to the mistake made in #1. Particularly for a > >distributed mission- > > critical system, this should be considered an absolute > >requirement. > > Yes, this is true. But you have to understand that the mere design of the SRI > made it very difficult to test it in an other way that performing a launch. > This is because of the tight integration of hard-to-fool hardware with software > in a black box functional unit. What can be your test strategy for a black box > containing an inertial central? If the software had been designed with less coupling > on this particular hardware, you could have test the software vs. a simulation of the > hardware and its environment. Here, the launch was the test. Read the final report. If you don't have a copy, see: http://www.esrin.esa.it/htdocs/tidc/Press/Press96/ariane5rep.html In particular: "It should be noted that for reasons of physical law, it is not feasible to test the SRI as a "black box" in the flight environment, unless one makes a completely realistic flight test, but it is possible to do ground testing by injecting simulated accelerometric signals in accordance with predicted flight parameters, while also using a turntable to simulate launcher angular movements. Had such a test been performed by the supplier or as part of the acceptance test, the failure mechanism would have been exposed." If language is a problem, I believe the report is also available in French. As someone who, today, is performing testing of coupled IRS and flight control systems in a ground-based environment, I am quite confident in the conclusions of the paper on this point. > Jean-Marc Jezequel Tel : +33 2 99847192 > IRISA/CNRS Fax : +33 2 99847171 > Campus de Beaulieu e-mail : jezequel@irisa.fr > F-35042 RENNES (FRANCE) http://www.irisa.fr/pampa/PROF/jmj.html -- LMTAS - The Fighter Enterprise - "Our Brand Means Quality" For job listings, other info: http://www.lmtas.com or http://www.lmco.com