Think that depends on how your distro addresses them, might be drivers, not too sure.
My debian addresses my HD as /dev/sda
My centOS workstation addresses my HD as /dev/hda, while in the same time addressing my USB stick as /dev/sda.
In the case you're not sure what yours are addressed as, run in CLI
dmesg | grep sda
dmesg | grep hda
for full output