confusion about file-system type name

SaintDanBert · 07-02-2018, 02:20 PM

Why does 'gparted' use fat32 for the media card file system type and then 'mount' report that the file system is vfat. I know that these names imply the same on-disk structures etc, but why do these utilities use different names?

Thanks in advance,
~~~ 0;-Dan

rknichols · 07-02-2018, 03:22 PM

The filesystem format is fat32. When mounting that filesystem, you can mount it using nothing but the fat32 features, or make use of the long filename extension that vfat provides. Until there is an actual long filename used, there is nothing to distinguish vfat from fat32. Linux typically defaults to mounting with long filenames allowed, i.e. as vfat, so that's what the mount command shows. You can force the filesystem to be mounted without the vfat feature by specifying "-t msdos", and any filenames you try to create there will be truncated to the DOS 8.3 format. The mount command will then report, "type msdos".

SaintDanBert · 07-02-2018, 03:27 PM

Is it the file system or win-dose that creates an 8.3 name for long filenames?

Where does exfat fit into all of this?

Thanks, again,
~~~ 0;-Dan

John VV · 07-02-2018, 03:32 PM

i might be wrong here so ...

Microsoft OWNS the patents on 8.3 long file name conversion that vfat is .

exfat is a work around of those patents

but please double check this

rknichols · 07-02-2018, 03:44 PM

Quote:

Originally Posted by John VV

Microsoft OWNS the patents on 8.3 long file name conversion that vfat is .

exfat is a work around of those patents

What?? exFAT is a Microsoft patented filesystem (US patent numbers 8583708 and 8321439, among others) that allows larger files and filesytems than does fat32 and has optimizations for flash memory devices. It also proprietary. Microsoft has not officially released the full exFAT specification.

X-LFS-2010 · 07-07-2018, 07:37 PM

Quote:

Originally Posted by John VV

i might be wrong here so ...

Microsoft OWNS the patents on 8.3 long file name conversion that vfat is .

exfat is a work around of those patents

but please double check this

microsoft was well know to

Mod's edit, removed most of post.
Please construct posts that use references to sources.

jefro · 07-09-2018, 01:15 PM

A different sites take on the question is here. https://stackoverflow.com/questions/...2-file-systems

yonnieboy · 07-10-2018, 02:57 PM

Quote:

Originally Posted by X-LFS-2010

microsoft was well know to

Mod's edit, removed most of post.
Please construct posts that use references to sources.

When a member posts a phrase such as "please double check this," it means that we need to verify this. It is not an argument point.

What is the point of this post? LinuxQuestions used to be a forum to get helpful answers to questions, users helping users. It is not a forum for promotion of arguments between users. It does not appear that the original question has really been addressed at all.

jefro · 07-10-2018, 03:07 PM

I edited that in error. The last paragraph was supposed to be my comment.

The original question has not been addressed as far as I know. If members have a better solution please post it.

SaintDanBert · 07-19-2018, 10:45 AM

Quote:

Originally Posted by jefro

I edited that in error. The last paragraph was supposed to be my comment.

The original question has not been addressed as far as I know. If members have a better solution please post it.

Your link to that article has answered some of my related questions about Fat32, VFAT and friends.
Thank you.

However, as you point out, I still don't understand why gparted reports one format while mount reports a different format. This is interesting and confusing given the article's explanation that VFAT and FAT32 are technically different file system designs and implementations.

From the mount man-page:

Code:

       -t, --types fstype
              The argument following the -t is used to indicate  the  filesystem  type.
              The  filesystem types which are currently supported depend on the running
              kernel.  See /proc/filesystems and /lib/modules/$(uname -r)/kernel/fs for
              a  complete  list  of  the  filesystems.  The most common are ext2, ext3,
              ext4, xfs, btrfs, vfat, sysfs, proc, nfs and cifs.

NOTICE -- There is no mention of either FAT or FAT32. Elsewhere in the man-page there is:

Code:

(Note:  fat is not a separate filesystem, but a common part of the msdos, umsdos
       and vfat filesystems.)

In order to find FATxx anything, you need options as part of mounting your filesystem:

Code:

       fat={12|16|32}
              Specify a 12, 16 or 32 bit fat.  This overrides the  automatic  FAT  type
              detection routine.  Use with caution!

... I'm off to play and learn how to default mount as FAT32...

Thanks in advance,
~~~ 0;-Dan

michaelk · 07-19-2018, 11:28 AM

My interpretation is the filesystem type name and driver is called vfat. The driver automatically detects the actual format (unless specified in the mount options) i.e FAT12/16/32 and VFAT. gparted reads the file system magic number as FAT32 since as far as I know there isn't a specific number for VFAT.

Quote:

I'm off to play and learn how to default mount as FAT32..

As the man mount page indicates it does this automatically if you do not specify fat=option

rknichols · 07-19-2018, 08:05 PM

Quote:

Originally Posted by SaintDanBert

I still don't understand why gparted reports one format while mount reports a different format. This is interesting and confusing given the article's explanation that VFAT and FAT32 are technically different file system designs and implementations.

They are not different filesystems. VFAT is a method of storing long filenames in a FAT12/16/32 filesystem. When the filesystem is formatted, it is just FAT12/16/32. When Linux mounts such a filesystem, it by default enables the VFAT extensions in the driver, so the mount command shows the mount type as VFAT. You can always force such a filesystem to be mounted as type "msdos". If you do that with a filesystem that already contains long names, you will not see the long names but only the shortened, unique 8.3 names that VFAT also stores for files that have names that violate the 8.3 format.

SaintDanBert · 07-19-2018, 08:07 PM

Quote:

Originally Posted by michaelk

...
As the man mount page indicates it does this automatically if you do not specify fat=option

When you connect a USB, SD-card or other similar device, "magic happens" ==> then the device appears mounted as ]b]/media/$USER/{identifier}[/b]. Something in this "magic" there is the automatic determination of the fstype to use for the associated mount command.

I know which of my devices I formatted as 'fat32'
new-from-the-store devices are likely to be some variant of 'msdos'
devices from other folks might be who-knows-what ... including 'exfat'

THEREFORE, I need to get into the fey with my rattle and beads to intercept the default automatic processing and set the correct --type value for the device that I actually connected.

Thanks in advance,
~~~ 0;-Dan