Is it okay to connect a internal hard drive (IDE/SATA/SCSI) to an internal controller (e.g. on-board the motherboard) and supply the power via another power supply or an external unit like the one below:
Does it matter if the external power supply is grounded or not?
EDIT: I'm aware the power supply below is grounded. If both the computer's PSU and the external adapter are grounded to earth, I assume there wouldn't be any problems. The one I have isn't. I'm afraid that the floating ground might cause problems. Any ideas?