Changes

The authoritative source of information about the Wii's metadata layout is [http://git.infradead.org/users/segher/wii.git?a=blob;f=zestig.c Segher's zestig.c], but here is an attempt to describe that in English.

The authoritative source of information about the Wii's metadata layout is [http://git.infradead.org/users/segher/wii.git?a=blob;f=zestig.c Segher's zestig.c], but here is an attempt to describe that in English.

Each metadata "superblock" starts with the 4 magic bytes "SFFS" (probably short for Secure FAT FileSystem), followed by a 4-byte "generation number" and another 4-byte number (always 0x10?). When accessing the FS, IOS will choose the superblock with the highest generation number and use it; whenever it modifies the filesystem in any way, it will increment the generation number by 1 and write out an entirely new superblock in the next slot (in round-robin order). This allows the history of the filesystem to be seen.

Each metadata "superblock" starts with the 4 magic bytes "SFFS" (probably short for Secure FAT FileSystem), followed by a 4-byte "generation number" and another 4-byte number (always 0x10?). When accessing the FS, IOS will choose the superblock with the generation number matching the one in SEEPROM and use it; whenever it modifies the filesystem in any way, it will increment the generation number in SEEPROM by 1, update the generation number of the superblock, and write out an entirely new superblock in the next slot (in round-robin order). This allows the history of the filesystem to be seen.

The next 0x10000 bytes (bytes 0xc:0x1000c within the superblock) are 0x8000 2-byte cluster numbers, and comprise the FAT. The FAT is followed by the FST — the tree structure containing the directory hierarchy and (plaintext!) filenames.

The next 0x10000 bytes (bytes 0xc:0x1000c within the superblock) are 0x8000 2-byte cluster numbers, and comprise the FAT. The FAT is followed by the FST — the tree structure containing the directory hierarchy and (plaintext!) filenames.