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From: KK6GM <mjsilva@scriptoriumdesigns.com>
Subject: Re: How would Ariane 5 have behaved if overflow checking were notturned off?
Date: Wed, 16 Mar 2011 12:40:00 -0700 (PDT)
Date: 2011-03-16T12:40:00-07:00	[thread overview]
Message-ID: <d6e065fb-7271-42d5-812c-83912c8721a5@n1g2000yqm.googlegroups.com> (raw)
In-Reply-To: 4d810172$0$4954$a8266bb1@postbox2.readnews.com

On Mar 16, 11:29 am, Hyman Rosen <hyro...@mail.com> wrote:
> How about this for the essential flaw: Does it really make
> sense to create data types in your program that are so closely
> tied to external factors like rocket speed limits and angles?
> Why not use data types that could handle the full range of
> values from the sensor? The approach used seems incredibly
> brittle, and in fact turned out to be so.

Here's the alternative, for the Ariane situation.  A float value gets
converted to a 16-bit integer.  The float value is too big to fit
(let's say it's 33000).  What 16-bit int will that get converted to?
-31000?  Some random value?  How does continuing along with bogus data
make the situation better?  Will the control loops really work OK with
bogus feedback data?

If you have determined via thorough analysis that the variable in
question can only _ever_ have a valid range of e.g. -20000 to 20000,
and it goes to 33000, what _is_ the right action?




  parent reply	other threads:[~2011-03-16 19:40 UTC|newest]

Thread overview: 79+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-14 15:49 How would Ariane 5 have behaved if overflow checking were not turned off? Elias Salomão Helou Neto
2011-03-14 16:17 ` KK6GM
2011-03-14 19:25   ` Yannick Duchêne (Hibou57)
2011-03-14 19:28     ` Vinzent Hoefler
2011-03-14 20:28     ` KK6GM
2011-03-15  4:02       ` Yannick Duchêne (Hibou57)
2011-03-15  4:53         ` Shark8
2011-03-14 18:29 ` Vinzent Hoefler
2011-03-16 10:41   ` How would Ariane 5 have behaved if overflow checking were notturned off? robin
2011-03-16 15:16     ` Simon Wright
2011-03-17 11:48       ` robin
2011-03-16 16:58     ` Martin Krischik
2011-03-16 23:39       ` How would Ariane 5 have behaved if overflow checking werenotturned off? robin
2011-03-17 18:48         ` Vinzent Hoefler
2011-03-18 12:06         ` Alex R. Mosteo
2011-03-18 21:15           ` How would Ariane 5 have behaved if overflow checking were not turned off? robin
2011-03-20 10:42             ` Vinzent Hoefler
2011-03-20 17:06         ` How would Ariane 5 have behaved if overflow checking werenotturned off? Martin Krischik
2011-03-20 17:11         ` Martin Krischik
2011-03-20 18:10           ` Dmitry A. Kazakov
2011-03-21 13:24         ` Leif Roar Moldskred
2011-03-20 13:07       ` How would Ariane 5 have behaved if overflow checking were notturned off? Florian Weimer
2011-03-20 17:00         ` Martin Krischik
2011-03-20 20:17           ` Florian Weimer
2011-03-20 20:37             ` Vinzent Hoefler
2011-03-20 20:14         ` Vinzent Hoefler
2011-03-16 18:20     ` Vinzent Hoefler
2011-03-16 18:29       ` Hyman Rosen
2011-03-16 18:55         ` Vinzent Hoefler
2011-03-16 19:40         ` KK6GM [this message]
2011-03-16 20:52           ` Hyman Rosen
2011-03-16 21:02             ` KK6GM
2011-03-16 21:09             ` Shark8
2011-03-16 21:13               ` Hyman Rosen
2011-03-16 21:35                 ` Shark8
2011-03-16 22:27             ` Vinzent Hoefler
2011-03-16 21:04           ` Shark8
2011-03-16 21:10             ` Hyman Rosen
2011-03-16 21:27               ` KK6GM
2011-03-16 21:31               ` Shark8
2011-03-16 22:32               ` Vinzent Hoefler
2011-03-18 21:14           ` How would Ariane 5 have behaved if overflow checking were not turned off? robin
2011-03-16 23:46       ` How would Ariane 5 have behaved if overflow checking werenotturned off? robin
2011-03-17  0:26         ` Simon Wright
2011-03-17 11:01           ` Georg Bauhaus
2011-03-17 11:04           ` robin
2011-03-17 13:36             ` Niklas Holsti
2011-03-18 21:13               ` How would Ariane 5 have behaved if overflow checking were not turned off? robin
2011-03-19 10:12                 ` Niklas Holsti
2011-03-17 22:51         ` How would Ariane 5 have behaved if overflow checking werenotturned off? Vinzent Hoefler
2011-03-18 21:13           ` How would Ariane 5 have behaved if overflow checking were not turned off? robin
2011-03-20 10:42             ` Vinzent Hoefler
2011-03-15  6:28 ` Stephen Leake
2011-03-15 17:32   ` Keith Thompson
2011-03-15 17:40     ` KK6GM
2011-03-15 19:44     ` Robert A Duff
2011-03-15 19:12   ` Florian Weimer
2011-03-15 19:45     ` KK6GM
2011-03-15 19:57     ` Vinzent Hoefler
2011-03-20 13:00       ` Florian Weimer
2011-03-20 20:13         ` Vinzent Hoefler
2011-03-15 19:42   ` John B. Matthews
2011-03-17 11:44   ` robin
2011-03-17 18:37     ` Vinzent Hoefler
2011-03-17 23:04       ` How would Ariane 5 have behaved if overflow checking were notturned off? robin
2011-03-18 15:55         ` Vinzent Hoefler
2011-03-17 21:37     ` How would Ariane 5 have behaved if overflow checking were not turned off? Vinzent Hoefler
2011-03-16 10:33 ` robin
2011-03-16 15:08   ` Simon Wright
2011-03-17 12:39     ` robin
2011-03-17 13:41       ` Georg Bauhaus
2011-03-17 23:34         ` How would Ariane 5 have behaved if overflow checking were notturned off? robin
2011-03-18 12:57           ` Hyman Rosen
2011-03-18 16:49             ` KK6GM
2011-03-18 17:18               ` Dmitry A. Kazakov
2011-03-19 17:55                 ` Keith Thompson
2011-03-20 18:39                   ` Robert A Duff
2011-03-17 18:43       ` How would Ariane 5 have behaved if overflow checking were not turned off? Vinzent Hoefler
2011-03-17 20:58       ` Simon Wright
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