Re: FAT32 superiority over ext2 :-)

[Daniel Phillips]

On Monday 25 June 2001 00:54, Albert D. Cahalan wrote:
> By dumb luck (?), FAT32 is compatible with the phase-tree algorithm
> as seen in Tux2. This means it offers full data integrity.
> Yep, it whips your typical journalling filesystem. Look at what
> we have in the superblock (boot sector):
>
>     __u32  fat32_length;  /* sectors/FAT */
>     __u16  flags;         /* bit 8: fat mirroring, low 4: active fat */
>     __u8   version[2];    /* major, minor filesystem version */
>     __u32  root_cluster;  /* first cluster in root directory */
>     __u16  info_sector;   /* filesystem info sector */
>
> All in one atomic write, one can...
>
> 1. change the active FAT
> 2. change the root directory
> 3. change the free space count
>
> That's enough to atomically move from one phase to the next.
> You create new directories in the free space, and make FAT
> changes to an inactive FAT copy. Then you write the superblock
> to atomically transition to the next phase.

Yes, FAT is what inspired me to go develop the algorithm.  However, two 
words: 'lost clusters'.  Now that may just be an implemenation detail ;-)

--
Daniel