create a corrupted FAT file system I have an application which will search for a corrupted FAT file system and repair it. For testing the application I will need a corrupted file system. What is a good and reproducible way for corrupting a FAT file system? Creating bad sectors for example.

a partial solution


dd if=/dev/zero count=100 bs=1k of=fs.fat
mkfs -t vfat fs.fat
mount fs.fat /mnt ## as root
# cp some file
umount /mnt ## as root

cp fs.fat fs.ref
vi fs.ref ## change some bytes
cp fs.ref fs.sampleX


now you have a good fs (`fs.fat`) and a corrupted one (`fs.ref`)


sudo mount -t vfat fs.ref /mnt
mount: wrong fs type, bad option, bad superblock on /dev/loop0,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so


* you can try to fix `fs.sampleX`
* knowing a bit about fat (or filesystem layout) might help to "cleverly corrupt" fs.ref
* this can be applied to any fs type (`extX`, `xfs`, ... )