Fault tolerance (was Re: OT Don't read this (was Re: Altair MBL source))

[Paul Koning]

>>>>> "woodelf" == woodelf  <bfranchuk at jetnet.ab.ca> writes:

 woodelf> chris wrote:
 >> I think the real lesson here is, don't let any computer be your
 >> sole method of controlling a warship... didn't these people watch
 >> Terminator?!? :-)
 >> 
 woodelf> I guess nobody in DC watches Classic Star Trek and installed
 woodelf> "manual over rides".  Funny in WWI & WWII warships worked
 woodelf> well with out puters but then they had 'sound powered
 woodelf> phones" for commication on ship -- no electricty needed --
 woodelf> just wire between phones.

In fairness, a lot of modern machinery can't be controlled by hand.
Don't know about ships, but, for example, most fighter planes can't be
flown without the help of their computers.

Then again, that's why those computers are 3-way (or more) redundant,
and their software development practices are supposed to be far more
rigorous than PC desktop software.

In extreme cases (Space Shuttle) you may see multiple control
computers with separately-developed software in them.  In the case of
the space shuttle, that didn't prevent a startup sync problem that
tripped up the countdown to the first launch, but in general it's a
good concept.  Hard to do and expensive, of course...

     paul