Hi,
I'm still in the process of understanding the special FS my PVR uses (see "Multiple files with same filename on FAT" thread a few days ago). I read the spec of the MBR and BootSector / BPB, and manually walked through these parts. I can see that the first (and only) partition is declared the standard way as a 16-bit FAT (06h) in the MBR. Although, the boot sector of this partition clearly corresponds to a FAT32 (with a few weird values in reserved fields, but well). The last field (filesystem type) even reads "FAT32 ".
I have a few questions though regarding the FAT itself (the actual linked list), that I'd like to submit to specialists (that's you :-)) :
- Can anybody explain me how to determine where the FAT starts on the disk ?
- Does anybody have an idea what the following structure is : The first non-zero sector I find after the BS is at BE00h (offset in bytes from start of disk) and looks like some kind of linked list on
24 (!) bits, stuffed with FF as fourth byte, like this : FF FF 1F 09 FF FF 1F FF 04 00 00 FF FF FF 1F FF DF 07 00 FF FF FF 1F FF 07 00 00 FF 08 00 00 FF 0A 00 00 FF FF FF 1F FF 0B 00 00 FF 0C 00 00 FF 0E 00 00 FF FF FF 1F FF 0F 00 00 FF 10 00 00 FF 11 00 00 FF 12 00 00 FF 13 00 00 FF 14 00 00 FF 15 00 00 FF 16 00 00 FF 17 00 00 FF 18 00 00 FF ... (and there's a copy of it starting at 31200h) I guess it's not the FAT yet, right ? A few bytes after the end of the that copy (at 56800h precisely), what I think is the actual FAT begins, like this : 81 00 00 00 82 00 00 00 83 00 00 00 84 00 00 00 85 00 00 00 86 00 00 00 87 00 00 00 88 00 00 00 89 00 00 00 8A 00 00 00 8B 00 00 00 8C 00 00 00 ... (and there's a copy of this one starting at 12F6200h)Any hint or information is welcome, of course
Vicne