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Re: Limits of reliability or is 99.999999999% realistic

  • From: Shawn McMahon
  • Date: Mon Nov 27 11:31:44 2000 
On Mon, Nov 27, 2000 at 11:07:34AM -0500, Marshall Eubanks wrote:
> 
> In spacecraft work, JPL has found that, if you did not
> strive for "5 sigma's" or even "6 sigma's" of reliability, then
> there would always be something you hadn't counted on that would
> drive reliability to zero.

NASA's needs don't reflect our needs.

If my router fails, I can get to it to fix it in seconds, and if I need
to replace it I don't have to wait five years to launch and another year
to reach the target.

If I have to have a replacement overnighted, I'm still only down a day,
not a decade.

Also, NASA's budget for a POP on Mars is a little higher than my budget
for a POP in Colorado Springs.  Hell, their budget for a single lander
is probably higher than my budget for an entire data center.

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