boot section corruption

[gahn]

hi all:

it is a just general question for freebsd/unix.

i got puzzled when sometime the freebsd either failed to  mount a slice, gets into mountroot> prompt or even worse, corrupted the whole boot section and gets into db> mode.besides the recovery procedures, i am more interested in knowing how those scenarios might happen and what we can do to prevent them to happen.

thanks

_dave