hiding files under a mount point.

[George Michaelson]

If you have some files in a directory eg /usr (on the root partition)
and you mount the filesystem /usr over them, they become "invisible".

How "invisible" are they? Can this be exploited meaningfully by sysops
or others to provide secure online storage of files you don't want
mortals to know about? (/usr is a bad example. unmounting makes the
system pretty useless. some other places might be more bearable.)

	-george

-- 
	G.Michaelson
Internet: G.Michaelson at cc.uq.oz.au                     Phone: +61 7 365 4079
  Postal: George Michaelson, the Prentice Centre,
          The University of Queensland, St Lucia, QLD Australia 4072.