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NNTP-Posting-Date: Wed, 06 Sep 2006 01:05:05 -0500
Date: Wed, 06 Sep 2006 07:05:00 +0100
From: Martin Dowie <martin.dowie@afraidof.co.uk>
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Subject: Re: Martian Rover Spirit's mulitasking software reset.
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Date: 2006-09-06T07:05:00+01:00
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ME wrote:
> The mars rover Spirit suffered a software reset as a result of a 
> multitasking problem.
> 
> "The apparent cause was that the rover's central processing unit was 
> overworked as several tasks were running in parallel at the time."
> 
>  
> 
> The rover uses VX works and I believe C. Testing obviously did not catch 
> this fault. Would the use of Ada  made any difference?
> 

My understanding is that there was a "priority inverstion", so had they 
used "pragma Locking_Policy (Ceiling_Locking);" (RM  D.3 Priority 
Ceiling Locking) then the problem could have been avioded.

Of course, they might not have used it even if they were using Ada. :-)
Cheers
-- Martin