Unable to mount FAT16 partition (Invalid Argument)

[Polytropon]

On Sun, 24 Mar 2019 20:42:30 -0500, Peter Erickson wrote:
> # mount -t msdosfs /dev/ada1p5 /mnt
> mount_msdosfs: /dev/ada1p5: Invalid argument

I have no idea if this applies, but I can imagine that FAT and GPT
don't work well together. GPT is "too new", and even on "Windows"
where GPT can be used, NTFS is used instead of FAT16. A FAT filesystem
is usually created on a DOS primary partition (a slice). A GPT
partition is something else...

Sidenote: For testing, always use -o ro or -r to make sure no
writes are allowed (or tried). Sometimes this allows you to mount
even damaged file systems. Try one of these:

	# mount -t msdosfs -r /dev/ada1p5 /mnt

	# mount_msdosfs -o ro /dev/ada1p5 /mnt

The use of "mount -t msdosfs" and "mount_msdosfs" should be equivalent.
See "man mount_msdosfs" for details.



> FWIW, knoppix has no issues mounting the partition, but I'd really be 
> interested in getting this to work on FreeBSD.
> 
> knoppix # mount | grep /dev/sdb5
> /dev/sdb5 on /mnt type vfat 
> (rw,relatime,fmask=0022,dmask=0022,codepage=850,iocharset=utf8,shortname=mixed,errors=remount-ro)
> 
> Based on the info from knoppix, I tried to mount the partition under 
> FreeBSD using mount_msdosfs directly and specifying the locale 
> (en_US.UTF-8) and codepage (CP850) , but the result was the same - 
> "Invalid argument."

Locale and codepage shouldn't have an effect on the basic mount
operation. Both are fairly standard and should be covered by the
defaults anyway.




-- 
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...