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-Thread: 103376,7e8cebf09cf80560
X-Google-NewGroupId: yes
X-Google-Attributes: gida07f3367d7,domainid0,public,usenet
X-Google-Language: ENGLISH,UTF8
Path: 
 g2news2.google.com!news4.google.com!feeder.news-service.com!94.75.214.39.MISMATCH!aioe.org!.POSTED!not-for-mail
From: "John B. Matthews" <nospam@nospam.invalid>
Newsgroups: comp.lang.ada
Subject: Re: How would Ariane 5 have behaved if overflow checking were not
 turned off?
Date: Tue, 15 Mar 2011 15:42:35 -0400
Organization: The Wasteland
Message-ID: <nospam-5DB536.15423415032011@news.aioe.org>
References: 
 <a8387564-0835-467d-a461-60a093c38133@k15g2000prk.googlegroups.com>
 <82d3lsvqw7.fsf@stephe-leake.org>
NNTP-Posting-Host: LQJtZWzu+iKlBROuDg+IUg.user.speranza.aioe.org
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
X-Complaints-To: abuse@aioe.org
User-Agent: MT-NewsWatcher/3.5.3b3 (Intel Mac OS X)
X-Notice: Filtered by postfilter v. 0.8.2
Xref: g2news2.google.com comp.lang.ada:19191
Date: 2011-03-15T15:42:35-04:00
List-Id: <comp.lang.ada>

In article <82d3lsvqw7.fsf@stephe-leake.org>,
 Stephen Leake <stephen_leake@stephe-leake.org> wrote:

> Elias Salomão Helou Neto <eshneto@gmail.com> writes:
> 
> > I have followed the (quite lenghty) on a topic, IIRC, about bitwise
> > operators, which eventually lead to people mentioning the Ariane 5
> > case.
> >
> > Since then I have been wondering. If compiler checking where actually
> > turned on, what would have happened? How could it avoid the disaster?
> 
> Just to remind people; the real problem was that Ariane 4 code was 
> reused on Ariane 5, without carefully considering the design, also 
> without adequate testing.
> 
> Ariane 5 is a bigger rocket; it has bigger accelerations. The range 
> for accelerations in the code, which was correct for Ariane 4, was 
> incorrect for Ariane 5.
> 
> No amount of "defensive programming" can handle such a fundamental 
> design error.

This comports with my understanding, based on this report:

ARIANE 5
Flight 501 Failure
Report by the Inquiry Board

<http://web.archive.org/web/20000815230639/www.esrin.esa.it/htdocs/tidc/Press/Press96/ariane5rep.html>

-- 
John B. Matthews
trashgod at gmail dot com
<http://sites.google.com/site/drjohnbmatthews>