[ale] semi [OT] running a robot with linux

[Tom Freeman]

On 01/25/2011 07:47 AM, John wrote:
> Space Shuttle GPCs?  What would you like to know? I wouldn't call them
> "tiny" since they were modified IBM 360 mainframes, there are 5 on-board
> with at least 3 running and checking each other in a redundant set.  I
> wrote GN&C code for AP101/S computers for 5 years in HAL/S + about 10
> other languages that most people have never heard about.
>
> Those systems each had 108KB of RAM when I started there, but that was
> upgraded to 256KB.  It wasn't about CPU as much as IO channels - except
> during guidance calculations. There were thousands of redundant channels
> for input/output.  I only know about 1 software error that impacted a
> shuttle mission ... and it was during satellite catch, release, catch,
> release, catch, release .... tests.  A few months later, a buddy changed
> that error accumulator from single precision into double precision and
> forced it to be reset to zero at the beginning of every new guidance
> calculation. Fairly simple fix. That code hadn't been touched in 15+
> years previously.
>
> Lots of stories from my time at JSC working on shuttle, space station
> and in the FCRs.
>
>    
Joining two threads here - but I would bet that there would be a great 
deal of interest in this group for a talk on the shuttle computers, the 
very aggressive QC program surrounding the computers. Not exactly Linux 
but almost certainly good for a good turnout.

IMHO of course
> On 01/24/2011 09:51 PM, Ron Frazier wrote:
>    
>> Hopefully, those computers are powerful ENOUGH.  I think the space
>> shuttle's original computers were similarly tiny.  Sometimes, more
>> complexity breeds more problems.
>>
>> Ron
>>      
>