rx50unit
printf("crxopen(csa%d)\n", rx50unit(dev));
if ((unit = rx50unit(dev)) >= 2)
printf("crxclose(csa%d)\n", rx50unit(dev));
rx50state.rs_flags &= ~(1 << rx50unit(dev)); /* atomic */
rx50unit(dev), uio->uio_rw==UIO_READ?"read":"write");
rs->rs_drive = rx50unit(dev);