Is there any difference between using Disk Utility (osx 10.6) to make a .dmg disk image of my "snow leopard" volume as opposed to a .dmg disk image of my Western Digital WD.... hard disk drive? The WD hard drive has only the one volume on it (1 partition). Disk Utility lets you choose either the physical disk or any volumes and I am wondering what the differences are in the situation where there is only 1 partition.