1.105: How can I unmount /usr to run fsck on it?

[ This is for 3.2. ]

In order to fsck /usr, it has to be unmounted. But /usr cannot be
unmounted because /bin is symbolically linked to /usr/bin. Also
/etc/fsck is symbolically linked to /usr/sbin/fsck.

To work around this, when you boot from the boot/maintenance diskettes
and enter maintenance mode, enter "getrootfs hdisk0 sh" instead of
"getrootfs hdisk0" where hdisk0 is the name of the boot disk. Then run
"fsck /dev/hd2".