I have a ext3 filesystem on a .img file. After mounting and unmounting it, I noticed that the md5sum is changed, even if no file inside was changed!
md5sum myfilesystem.img XXXX myfilesystem.img mount -t ext3 myfilesystem.img temp/ umount temp/ md5sum myfilesystem.img YYYY myfilesystem.img
Why does XXXX differs from YYYY? I clearly didn't touch anything inside myfilesystem.img.