/mnt is just the place where the directories that tend to become mount points are stored.
if you want another point just "mkdir /mnt/whatever"
but you have to then use the mount command to actually link some file system with the point, like this:
mount -t fat /dev/fd0 /mnt/floppy
/dev/fd0 is the device that represents the first floppy drive
note that you also have preconfigured mount points in /dev/fstab, which will simplify the above command into
The dev directory stores links into the drivers. /dev/fd0 is your floppy drive. /dev/hda1 is the first partition on your primary master drive (assuming ATA/EIDE of course) /dev/sound/dsp or /dev/dsp is your sound card. They are not themselves the drivers. The loadable drivers are stored in /lib/modules/$KERNEL_VERSION.