Is Python your only programming language?

Richard Brodie R.Brodie at rl.ac.uk
Thu Aug 14 17:26:34 CEST 2003


<sismex01 at hebmex.com> wrote in message news:mailman.1060872297.29542.python-list at python.org...

> As an example, someone mentioned the Arianne accident, a few years
> back, which was "caused" by a Zero-division error caught by the
> code, which raised some kind of error condition (I don't do Ada).

No, it was an overflow converting a floating point to integer.
The module was originally designed for Arianne 4, which had
different flight characteristics.

> BUT, it seems that the segment of code being checked wasn't even
> going to be executed (something about horizontan acceleration),
> and since the rocket was already in the air, that code shouldn't
> have mattered; "if it was C, then the operation would have silently
> failed, and the rocket would have kept flying".

It was in a background task, that was unnecessary. However the
exception handling was specified to be: write results to EEPROM
and halt. It's true that in C one would likely have garbage values
in the integer, and the error would have gone unnoticed. I'm not
sure I find that a comforting thought though.

The full text of the report is on the web, and should be required
reading:

http://www.mssl.ucl.ac.uk/www_plasma/missions/cluster/about_cluster/cluster1/ariane5rep.html






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