We configured our bb xM so that the boot filesystem was mounted
read-only and the root filesystem was type ext4. These steps seemed to
produce a system that could be shut down just by killing the power at will.
We tested the system by killing power random for 2k trials and it always
survived.
WARNING: I can't say how robust this configuration really is: It may be
fragile during boot and we may have just been very lucky. For our part
we're using the bb xM configured as above as the basis for an embedded
system that is controlled simply by the user applying or removing power.
- martin smith
(This is an individual reply; can't seem to post via gmane.org.)