David Mathog wrote:
> Under what circumstances would turning off the power cause
> a disk to develop a pair of adjacent unreadable blocks?
> Or do you think they were already there and the reboot just
> revealed them?
>

Bad blocks can sit unnoticed for a long period of time. You
didn't do anything wrong. I work in a lab with ~300 various
machines on a UPS. Usually the UNIX machines will be up
and running for over a year, even years. Whenever we do a
power shutdown, we loose 5-10 drives no matter how we
shut the machines down.