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: fac41,2c6139ce13be9980 X-Google-Attributes: gidfac41,public X-Google-Thread: f43e6,2c6139ce13be9980 X-Google-Attributes: gidf43e6,public X-Google-Thread: 1108a1,2c6139ce13be9980 X-Google-Attributes: gid1108a1,public X-Google-Thread: 103376,3d3f20d31be1c33a X-Google-Attributes: gid103376,public From: Luther Hampton Subject: Re: The presuppositions of all the Ariane 5 analysts. Date: 1997/07/22 Message-ID: <33D4647D.6D2A@erols.com>#1/1 X-Deja-AN: 258381481 References: <33C835A5.362A@flash.net> <33CC0548.4099@flash.net> <5qitoi$fdv$1@news.irisa.fr> <33CD6512.2404@flash.net> <01bc92e6$7a6f9e40$287b7b7a@tlo2> <33CEAF05.6389@flash.net> <33D2827B.41C67EA6@eiffel.com> <5qucs7$jie$3@flood.weeg.uiowa.edu> <33D3C7E4.764E@link.com> Organization: Lockheed Martin Corp, Valley Forge PA Reply-To: lhampton@erols.com Newsgroups: comp.object,comp.software-eng,comp.lang.ada,comp.lang.eiffel Date: 1997-07-22T00:00:00+00:00 List-Id: Samuel Mize wrote: > > Robert Dewar wrote: > > > > Bertrand said > > > > <<>All this is rhetorics and cannot succeed to obscure the basic > > >claim that systematic use of Design by Contract would probably > > >have avoided the crash. > > >> > > > > Well all sorts of things would have avoided the crash. One can also say > > that systematic proof of correctness, or systematic code review, or > > in fact almost any steps to be a bit more careful in this particular > > area, would have avoided the crash. > > This seems to touch the central core of the disagreement. Mr. > Meyer published a paper which said (paraphrasing wildly): > > 1) DBC would probably have prevented the crash. > 2) Only Eiffel properly supports DBC. > 3) Draw your own conclusions. > > I think it's fair to infer that the author considers this a > normal, adequately managed non-DBC project. I don't know if > he states this outright, but it would be nugatory indeed to > suggest that a new method would help when the previous methods > were not being properly applied. It's rather like claiming > that a new version of GPS, used properly, would have prevented > the Exxon Valdez crash. That's true, but normal navigation > aids, used properly, would have prevented it too. > There is nothing in your paraphrase to support the contention that "only" Design by Contract would have averted the problem. (1) states that DBC would do the trick, but it does not say that *only* DBC would have solved the problem. > Stating ONLY that the new item would have prevented the crash > is a misleading half truth. > I don't think that's what he said. I assume you are still claiming he said only DBC would have prevented the problem, he didn't. Statement (2), that Eiffel is the only language which supports DBC, is much more controversial. Meyer makes no secret of the fact that he considers Eiffel the solution to many software development problems. He has not claimed to be objective, he is pointing out that a feature of Eiffel would have helped here. This is (Eiffel/self-)promotion, but I think it is acceptable disourse inside the newsgroup. > So even if Meyer's paper is technically correct to suggest > that rigorous DBC would "probably" have located the error, > it is disingenuous to state ONLY that, without pointing out > that common methods of analysis or test would ALSO have > located the error. > See above. > It also seems fair to say that, if DBC had been used as > thoroughlessly as other methods were, it probably would NOT > have detected the problem. > Agreed. No method/language/tool can be effective if it is not properly employed. As you pointed out earlier, the major fault for the failure appaers to lie with the management, which apparently didn't enforce the procedures that were in place. That is not to say, however, that Eiffel or DBC might have helped.