http://www.hexus.net/content/item.php?item=4817The N2050 could be described most simply as a external SATA device which also has a SATA to USB bridge. It's a little more complex than that, however, as it's also a RAID device. So, inside there are two SATA 3Gbps channels, connected to a storage processor, charged with creating a RAID-0 or RAID-1 array from two attached drives. It is this RAID entity that is then presented via the eSATA or USB interface. Clever, eh?