On Mon, Mar 07, 2005 at 04:30:54PM +0800, Water NB scribed:
> 1) How to set password that prevent everyone entering single mode during
> booting?

from init(8) manpage:

If the `console' entry in the ttys(5) file is marked ``insecure'', then
init will require that the superuser password be entered before the sys-
tem will start a single-user shell.  The password check is skipped if the
`console' is marked as ``secure''.