PPRuNe Forums - View Single Post - AF 447 Search to resume (part2)
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Old 24th May 2011, 00:05
  #2214 (permalink)  
Join Date: Jun 2009
Location: Oxford, England
Posts: 297
Please tell me I'm not putting my life in the metaphorical hands of a
potential priority inversion or interrupts left off for too long. And I
hope the CPUs and hardware on the flying planes are used at about 10% of
their ultimate capacity if they are using multi-tasking.
The PI bug was almost unbelievable, but one suspects that internal politics,
project cost sensitivity issues etc were a factor in that one. Not something
that all software engineers would have experience of or be trained to recognise
at the time either. It's easy to be smug and there's plenty of info on the web on PI
now, but have yet to see a book that deals with it in depth and how to prevent it.

As for rtos, my (avionics) experience in that area is not current, but iirc,
there are at least two rtos's that are fully qualified to DO178 level, so it's
quite likely that they are being used. I would need to check what level
they are qualified to, but no company invests that amount of development
time and resource to such a project without the objective of making a lot of
money in return. You could check the Wind River site, or whatever they
are called now, for starters.

I don't see any problem with rtos, (treading carefully) and there may be
no alternative in that the business pressures, regulatory environment
and general competitive pressure mean that ever more complex solutions
are and will be needed to satisfy requirements. There's only so far that
you can go in simplifying a complex system and still have it work at all.

Of course, development processes and tools need to keep up with it all and
this is also cost driven to a degree (Again :-)...
syseng68k is offline