Something
public text v1 · immutable# mount -t vfat /dev/hda5 /mnt/windows -o ro
FAT: Did not find valid FSINFO signature.
Found signature1 0x0 signature2 0x0 sector=4.
VFS: Can't find a valid FAT filesystem on dev 03:05.
mount: wrong fs type, bad option, bad superblock on /dev/hda5,
missing codepage or other error
In some cases useful info is found in syslog - try
dmesg | tail or so