cvs commit: src/sys/fs/msdosfs msdosfs_vfsops.c

Ben Kaduk minimarmot at
Sat Jul 14 21:13:44 UTC 2007

On 7/14/07, Bruce Evans <brde at> wrote:
> On Fri, 13 Jul 2007, Ben Kaduk wrote:
> > I recently got a patch committed to the installation chapter of the
> > handbook, which included two occasions of clarifying ``MS-DOS
> > filesystem'' as ``FAT16 or FAT32'' [1,2 for present incarnation].  I
> > am too young to remember the existence of FAT12, so I'll have to defer
> > to others as to whether the handbook should mention FAT12 in the same
> > breath as FAT16 and FAT32.  What do you think?
> I think FAT* is newspeak :-).  The file system is named msdosfs, not FAT.
> Anyway, the number of bits per FAT entry is of no interest in most cases,
> so it shouldn't be emphasized.  newfs_msdos will choose the best number,
> or if you tell it, any number that can work.  newfs_msdos(8) says
> "construct a new MS-DOS (FAT) file system ... creates a FAT12, FAT16 or
> FAT32 file system".  It doesn't say anything about how newfs_msdos chooses
> the best FAT size or other important parameters.  newfs_msdos still hasn't
> caught up with the renaming of file systems from foo to foofs.
> > [1]
> >
> > [2]
> >
> A quick reading showed some bugs in [2]:
> - just after "FAT16 and FAT32", it says "The utility most common usage is
>    # mount_msdosfs /dev/ad0s1 /mnt".  It should say something like "This
>    utility's most common usage is indirectly via a line in /etc/fstab or
>    mount -t msdosfs.  [Example line in fstab, and the above command line
>    with direct use of mount_msdosfs fixed.]  This [section of?] the
>    handbook is too small to describe utilities in not most common usage
>    like newfs_msdos."
> - a little later, it says It says "Extended MS-DOS file systems are usually
>    mapped after FreeBSD partitions ... with the extended MS-DOS partition
>    located on /dev/ad0s3", but there is no such thing as an extended MS-DOS
>    file system.  It should say something like "MS-DOS logical drives are
>    usually mapped after primary partitions ... with the first logical drive
>    being /dev/ad0s3" and possibly add some details ("partition" here means
>    an MS-DOS primary partition; MS-DOS extended partitions aren't mapped;
>    MS-DOS logical drives correspond to FreeBSD slices, except for primary
>    partitions the partitions correspond to slices; check that in MS-DOS
>    speak, primary partitions aren't described as logical drives; logical
>    drives may or may not contain a file system, but in this example
>    /dev/ad0s3 has an MS-DOS file system, and I didn't reword things enough
>    to describe this).
> Bruce

Thanks, Bruce.

I will package your corrections into a patch and send it to the folks
at -doc@ .  I suppose I _should_ take this as a lesson to not mix
content changes with grammar/punctuation changes (I am trying to sweep
the handbook for such), but it will probably be too hard for me to
ignore some of them.

-Ben Kaduk

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