Andrew Morton wrote:

quoted

 And as long as your 100% confident that UPS's will never fail,
janitors will never accidentally hit the Emergency Power Office
switch, and so on.

Well.  The product of two very small numbers is...

Another unquantified very small number.

You have a UPS, but the first time you discover it's not wired up
properly is when it fails.

This happened recently in a customer's office...  The UPS power wiring
melted, leaving a big stinking hole, and all the servers went down -
quickly.

Another is misconfiguring the UPS daemon so it continues writing to
disk for 30 minutes until the battery runs down...

Like the chance of two disks going wrong in a RAID at the same
time... that would *never* happen would it?

*tip-toes out of the room*

-- Jamie