Putting this post on this list might head off more (private) emails on this subject. sdparm uses the START STOP UNIT SCSI command to start and stop (spin up and spin down) SCSI devices. Currently libata does not implement that SCSI command. [Hopefully Jeff contradicts me.] Has anybody seen a USB or 1394 enclosure that implements START STOP UNIT? [The command is defined in SBC, MMC and RBC.] Doug Gilbert - : send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html