FAT FileSystem Checking

Hi guys,
As far as I am aware, no filesystem error/integrity checker (a la chkdsk or e2fsck) exists for Wii.
I'm unlikely to have the experience to write it, but I'm interested in the theory, even if I can't manage the practical.
I feel the Wii could use the ability to check if a FAT partition has been messed up, and hopefully I am not alone there.
Where would someone even start with something like this?

Cheers.

from personal experience i can several other devices which are much worse at handling fat sectors, mainly ds flash carts seem to require a fat filesystem check every boot.

also if the sd card is buggered how would you load the app in the first place

Why, over one of the other ways of course! There are usb disk drive support, networking and the usbgecko, and of course, one bad sd card does not mean that all sd cards are bad.

The reliability of FAT support on other devices is kinda irrelevant here.
As for loading in the case of a completely non-functional filesystem... there are other ways to start an application. USB pen/harddisk drives, wiiload over wifi, wiiload over usbgecko.
However, I am mainly thinking of the cases in which there is an issue, but not severe enough to block all access.

For example, unmounting the filesystem incorrectly seems to cause issues. In this case, my SD reader can read the card, but XP sees the filesystem as RAW. Functionality is reduced, things aren't as stable, including file size and total size oddities, but read/write still works. Similar behaviour occurs when using it with the Wii. A run of chkdsk fixes it up nicely.

Any other thoughts?

If you want to create a corrupted file there is my application in the sqlite topic that creates a file that is not even copiable or moved.
Doing a chkdsk fix it (but the file data is corrupted) so it could be' used as test case :)