ADFS_DR_SIZE_BITS
dm[0].dm_startbit = 32 + ADFS_DR_SIZE_BITS;
dm[zone].dm_startblk = zone * zone_size - ADFS_DR_SIZE_BITS;
size -= (nzones - 1) * zone_size - ADFS_DR_SIZE_BITS;
((nzones > 1) ? ADFS_DR_SIZE_BITS : 0);