I am trying to read files of an AppleDOS 3.3 disk. The documentation I've found, both from Inside AppleDOS and also from Archiveteams' website (which I believe was taken from Inside AppleDOS): http://fileformats.archiveteam.org/wiki/Apple_DOS_file_system describes it in a lot of detail. The VTOC is the root block for the filesystem; it lives at 0x11000 in the image; it contains a pointer to the first directory block and also contains the bitmap.
However, my disk is a bit exotic. It's not a standard 35-track Apple disk; instead it's one of the rarer 80-track DSDD disks used by third-party disk expansions and clone systems. It's still the AppleDOS file format, except with 160 logical tracks (80 on one side and another 80 on the other.)
Except... the VTOC only has room for 50 tracks of bitmap, and this disk has 160. So, for the file system to work, the bitmap for the other
90 110 tracks must be somewhere.
Does anyone know where? As this is from a clone system, it's obviously not described in Apple's documentation!
(It's not in the logical sector immediately following the VTOC --- on my disk image, that's part of the directory. And yes, I have remembered about the AppleDOS sector translation!)