+extern uint8_t mfNumBlocksPerSector(uint8_t sectorNo);
+extern uint8_t mfFirstBlockOfSector(uint8_t sectorNo);
+extern uint8_t mfSectorTrailer(uint8_t blockNo);
+extern bool mfIsSectorTrailer(uint8_t blockNo);
+extern uint8_t mfSectorNum(uint8_t blockNo);