how to format my external drive?

[yellowdog-newbie@lists.terrasoftsolutions.com]

I also experienced the kernel panick recently with ext2fs.
If your mac os x crashes (which of course almost never happens,
but still...) then your linux partition has not been cleanly
unmounted. You reboot mac osx and after a terribly long wait
get a message that the linux partition can't be mounted because
it is not in order. Reboot into yellowdog linux, fsck is invoked
during startup to check the partition. In my case it is quite ok and
everything is back to normal. The problem has been discussed at
the ext2fs forum on sourceforge and one advice is to do a little
hacking so that your linux partition is only mounted read-only
by macosx. Then there should be no bad consequences of mac crashing
(not that it ever does, but...)