write_drive
write_drive(drive, (void *) vhdr, VINUMHEADERLEN, VINUM_LABEL_OFFSET);
error = write_drive(drive, (char *) vhdr, VINUMHEADERLEN, VINUM_LABEL_OFFSET);
error = write_drive(drive, config, MAXCONFIG, VINUM_CONFIG_OFFSET); /* first config copy */
error = write_drive(drive, config, MAXCONFIG, VINUM_CONFIG_OFFSET + MAXCONFIG); /* second copy */