Reading MSDOS Disks on the QL – Part III: The Boot Record and File Allocation Table

Parts I and II implicitly assumed a 40-track disk being used on an 80-track drive. Examining the boot record will be primarily useful in determing whether this is, in fact, the case. All the MSDOS disks I have so far examined have been the 40_track (720 sector) type but others are possible. In fact, there are six “standard” floppy-disk formats in the IBM PC zoo, covering the range from 320 to 2400 total sectors per disk.