All SCSI-2 drives fall again into SCSI-1, which the A2090 uses. SCSI-2 drives are okay too, but not at the full potential of the newer bus. There are different elective arguments of setClass() which you can discover in the help part with ? http://sk.nfe.go.th/hatyai06/index.php?name=webboard&file=read&id=253395