if (wait_for_unbusy (chp, howlong)) return -1;
wdc_select_drive(chp, drive, howlong)	struct channel_softc *chp;	int drive;	int howlong;{	if (wait_for_unbusy (chp, howlong))		return -1;	bus_space_write_1(chp->cmd_iot, chp->cmd_ioh, wd_sdh,	    WDSD_IBM | (drive << 4));		delay(1);	if (wdcwait(chp, WDCS_DRQ, 0, howlong))		return -1;	return 0;}