INT 13,18 - Set Media Type for Format (BIOS date specific)
AH = 18h CH = lower 8 bits of number of tracks (0-1023 dec., see below) CL = sectors per track (1-17 dec., see below) DL = drive number (0=A:, 1=2nd floppy, 80h=drive 0, 81h=drive 1) on return: ES:DI = pointer to 11-byte Disk Base Table (DBT) AH = 00h if requested combination supported = 01h if function not available = 0Ch if not supported or drive type unknown = 80h if there is no media in the drive CF = 0 if successful = 1 if error - valid only for XT BIOS dated after 1/10/86, AT after 11/15/86, XT 286 and the PS/2 line - only disk number is checked for validity - track number is a 10 bit value taken from the 2 high order bits of CL and the 8 bits in CH (low order 8 bits of track): │F│E│D│C│B│A│9│8│7│6│5│4│3│2│1│0│ CX │ │ │ │ │ │ │ │ │ │ └─┴─┴─┴─┴─┴──── sectors per track count │ │ │ │ │ │ │ │ └─┴──────────── high order 2 bits track/cyl count └─┴─┴─┴─┴─┴─┴─┴──────────── low order 8 bits of track/cyl count - see INT 13,STATUS