Ext. Type of file BAK Backup BAS BASIC source code BAT DOS, OS/2 batch file BFC Windows briefcase document BIN BINary (miscellaneous) BLX Magellan topographic data BM1 Apogee BioMenace file BML Bookmark library (SyncURL) BMP Windows & OS/2 bitmap BMK Windows help bookmarks BMS BlackMagic script BPD PS binary printer description BPD FARSITE burn period (times & dates) BRK Brooktrout fax BS1 Apogee Blake Stone BUP Backup to IFO file B64 MIME encoded (Base 64)