FDPART
if (FDPART(dev) >= FDMAXPARTS)
if (sc->openpart == FDPART(dev))
sc->openpart = FDPART(dev);
fdgetdefaultlabel(sc, (struct disklabel *)addr, FDPART(dev));
sc->dkdev.dk_label->d_npartitions == (FDPART(dev) + 1))
part = FDPART(dev);