control_bis
out_8(&sw->control_bis, DRIVE_ENABLE);
out_8(&sw->control_bis, SELECT);
out_8(&sw->control_bis, DO_ACTION);
out_8(&sw->control_bis, DO_SEEK);
out_8(&sw->control_bis, WRITE_SECTORS);
out_8(&sw->control_bis, DO_ACTION);
out_8(&sw->control_bis, DRIVE_ENABLE | INTR_ENABLE);