MSG_IDENTIFY_DR
SEND_BYTE(regs, MSG_IDENTIFY_DR | lun);
SEND_BYTE (regs, MSG_IDENTIFY_DR | lun);
acb->msgout[0] = MSG_IDENTIFY_DR | lun;
acb->msgout[0] = MSG_IDENTIFY_DR | lun;
SEND_BYTE (regs, MSG_IDENTIFY_DR | lun);