well, "dev" is you device listing, so all of the hard devices are listed in /dev/.
hdd would be the fourth disk on your ide channels (usually a cd rom disk).
the first disk is labled hda, secon hdb, ect.
So if you were installing on a fresh computer, you would install to /dev/hdd
this is also how the boot record is written, it tells grub or lilo where to boot from.
You can't really install another OS without altering the master boot record, you have to install a bootloader to manage the os choices.
Last time I checked, SuSE used grub as a bootloader. If you want the hardcores of it, or are just looking for a better explaination, check out the gentoo docs on grub at http://www.gentoo.org/doc/en/handboo...?part=1&chap=9