XFS: the filesystem of the future?

The "extended ATA" command set that's used on SATA devices not operating in Legacy IDE mode is the SCSI command set. This goes all the way back to ATAPI which is the SCSI command set encapsulated with the IDE bus protocol. Drives and controllers are capable of speaking either SATA-II or SAS protocols without any cost difference AFAICT but don't, for largely marketing reasons rather than engineering ones. As I was saying before, having a command queue on the drive allows for the drive to have an IO elevator which is _the_ big performance win, details about how commands are named and whatnot is not really an important factor.