From: Alan Brain <aebrain@dynamite.com.au>
Subject: Re: Ariane 5 Failure - Summary Report
Date: 1996/07/25
Date: 1996-07-25T00:00:00+00:00 [thread overview]
Message-ID: <4t7fs4$bq62@red.interact.net.au> (raw)
In-Reply-To: 31F629B8.5FFB@lmtas.lmco.com
Ken Garlington <garlingtonke@lmtas.lmco.com> wrote:
>So, anyway, we now have another software package written in Ada that
>caused the loss of a system, and again specification and design issues
>outside Ada's control are the culprit.
Not just design and specification, the implementation as well.
Firstly, the brain-dead attitude of "handle all exceptions by shutting down and
going to the backup" on a complex piece of equipment without many, many redundancies
is ... incredible. Only duplication? Glad I'm not riding it... So that's a
Specification fault.
Secondly, the notion that conversion from a 64-bit value to a 16 bit value will
always be OK, and that any time it isn't means a total failure of the unit, is a bit
hard to swallow. In a complex piece of software, incapable of strict mathematical
verification, I'd expect this to happen sometimes, not because of any soft failure
or random hardware failure, but because Software Has Bugs. That's no excuse for
losing a payload! This is a design fault.
Thirdly, assuming either of the above, not checking that an arithmetic operation of
this kind before it's fully complete is just plain silly. And such a check is un
morceau de gateaux. This is an implementation fault.
Jeez, Ada provides safety belts, Anti-lock brakes, etc but if people don't buckle
up, and don't even bother to use the brake peddle, what can you do?
next prev parent reply other threads:[~1996-07-25 0:00 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <31F60E8A.2D74@lmtas.lmco.com>
1996-07-24 0:00 ` Ariane 5 Failure - Summary Report Ken Garlington
1996-07-24 0:00 ` Byron B. Kauffman
1996-07-24 0:00 ` Stephen D. House
1996-07-25 0:00 ` Theodore E. Dennison
1996-07-25 0:00 ` ++ robin
1996-07-26 0:00 ` ++ robin
1996-07-26 0:00 ` Ken Garlington
1996-07-30 0:00 ` Theodore E. Dennison
1996-07-25 0:00 ` Alan Brain [this message]
1996-07-29 0:00 ` Ken Garlington
1996-07-30 0:00 ` John McCabe
1996-07-25 0:00 ` Dale Stanbrough
1996-07-26 0:00 ` OS2 User
1996-07-25 0:00 ` ++ robin
1996-07-26 0:00 ` Con Bradley
1996-07-26 0:00 ` P. Cnudde VH14 (8218)
1996-07-26 0:00 ` Peter Hermann
1996-08-01 0:00 ` root
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