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From: Ken Garlington <GarlingtonKE@lmtas.lmco.com>
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: <3332C211.3C07@lmtas.lmco.com>#1/1
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References: <332B5495.167EB0E7@eiffel.com> <tz8ohcjv7cc.fsf@aimnet.com>
 <dewar.858568071@merv> <5giu3p$beb$1@news.irisa.fr>
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 <33302A36.7434@lmtas.lmco.com>
 <01bc356c$e3aae860$371883cc@beast.advancedsw.com>
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: <comp.lang.ada>


Roger T. wrote:
> 
> The problem is not the language or the lack or presence of assertions. The
> problem is having people doing design who don't understand dynamic systems,
> especially feedback.

I appreciate the wisdom of anyone who agrees with me ;) but I do want to
make
sure that my comments are not misunderstood. Even with a highly-trained
team
who has a great deal of knowledge about their product (in this case, an
inertial reference system), it is very easy to have insufficient
information
on, or experience in, the *total* system (missile, aircraft, etc.) in
which
the IRS is used. In fact, the final report makes it clear that useful
data on the Ariane V was left out of the specification. Furthermore,
even
if the information were available, it is very difficult to translate
such
high-level system information into the detailed data necessary to
determine
such things as parameter ranges.

To summarize: I am not saying the IRS team was stupid, lazy, etc. I am
saying
that this is a difficult business. I consider myself a reasonably
confident
flight controls software engineer. However, I also consider myself
human,
and capable of mistakes. That is why I would never permit my work to be
used
without extensive testing by an independent group, including the end
user
(a pilot, in my case).

> 
> Roger T.

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