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 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,CP1252 X-Google-Thread: 103376,f039470e8f537101 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2003-07-23 16:10:16 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!logbridge.uoregon.edu!arclight.uoregon.edu!wn13feed!wn12feed!worldnet.att.net!204.127.198.203!attbi_feed3!attbi.com!rwcrnsc52.ops.asp.att.net.POSTED!not-for-mail Message-ID: <3F1F15D6.4030800@attbi.com> From: "Robert I. Eachus" User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.0.2) Gecko/20021120 Netscape/7.01 X-Accept-Language: en-us, en MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: Ariane5 FAQ References: <1058810510.375902@master.nyc.kbcfp.com> <1058813341.841940@master.nyc.kbcfp.com> <1058816605.566685@master.nyc.kbcfp.com> <1058969472.350716@master.nyc.kbcfp.com> <20619edc.0307231233.24f27e91@posting.google.com> <1058996131.223000@master.nyc.kbcfp.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit NNTP-Posting-Host: 66.31.71.243 X-Complaints-To: abuse@comcast.net X-Trace: rwcrnsc52.ops.asp.att.net 1059001816 66.31.71.243 (Wed, 23 Jul 2003 23:10:16 GMT) NNTP-Posting-Date: Wed, 23 Jul 2003 23:10:16 GMT Organization: Comcast Online Date: Wed, 23 Jul 2003 23:10:16 GMT Xref: archiver1.google.com comp.lang.ada:40736 Date: 2003-07-23T23:10:16+00:00 List-Id: Hyman Rosen wrote: > Mike Silva wrote: > >> So you are arguing that, lacking written documentation to the >> contrary, any piece of code should be assumed capable of handling all >> possible input values in a way that is appropriate to all possible >> systems in which the code is employed. Tell me, honestly, would you >> fly in a rocket designed under such assumptions? > > > But we're not talking about "any-all". This was a combined > hardware and software module being moved from one rocket > version to the next. > >> the Ariane-5 people had no legitimate reason to assume that what > > > the code did would also be right in the Ariane-5 system. > > And yet they acted that way. That argues that they did have > a legitimate reason. Even though it turned out to be wrong > in retrospect. As I keep saying, there is a difference between > "no reason to assume it will work" and "reasons why it will > not work". Yes, several someones assumed that the software HAD been designed with the Ariane 4 and Ariane 5 requirements in mind. But a political/financial decision was made not to allow the team developing the SRI to have access to the Ariane 5 performance data. The reasoning behind that decision was that it would give them a leg up on other bidders for portions of the Ariane 5 software development. This was probably true. So the requirements scrub should have been done by the Ariane 5 developers. But that never got done because they did not have access to the SRI documentation, just the source code. THAT was the monumental stupid blunder. Eliminating (for financial reasons) the scheduled tests in which the guidance system would be ground tested with Ariane 5 trajectory data was the (third) shoe. It took all three pieces to make a disaster, and there is (fairly obviously) no evidence of collusion. -- Robert I. Eachus �In an ally, considerations of house, clan, planet, race are insignificant beside two prime questions, which are: 1. Can he shoot? 2. Will he aim at your enemy?� -- from the Laiden novels by Sharon Lee and Steve Miller.