I didn't know how to format an unformatted drive under Linux. I attached a firewire case with an old 12 GB Macintosh-formatted HD to my computer. In order to format it with reiserfs, I used Yast2. I had to go to expert mode and rewrite the partition table. By this action Yast2 puts an entry into the fstab, that I modified to:
/dev/sda1 /media/firewire reiserfs noauto,user 0 0
since I don't want to have it connected every time I boot up. Instead I can now mount it as a regular user manually with:
mount /media/tmp/
To make the drive writable to normal users (or to whomever you want to grant access) you need to change the ownership and/or permissions of the mountpoint:
chmod -R a+rwx /media/firewire