sdstrategy
{ "sd", sdstrategy, sdopen, sdclose, sdioctl },
int sdstrategy(void *, int, daddr_t, size_t, void *, size_t *);
return readdisklabel(DISKLABELDEV(dev), sdstrategy, lp, spoofonly);
return physio(sdstrategy, dev, B_READ, sdminphys, uio);
return physio(sdstrategy, dev, B_WRITE, sdminphys, uio);
sdstrategy, sc->sc_dk.dk_label);