New drive already has vfat after new fdisk

[Steven Ringwald]

On Thu, 2006-01-26 at 16:15 -0500, Nat Gross wrote:
> On 1/26/06, Andy Green <andy at warmcat.com> wrote:
> > Nat Gross wrote:
> >
> > >>What led you to the conclusion that it is VFAT?  I didn't see anything
> > >>showing that in your mail.
> > >
> > > oops. Should have mentioned. Gnome System Monitor showed it as vfat/
> >
> > > /dev/sda1 on /media/usbdisk type vfat (rw,nosuid,nodev,_netdev,utf8)
> >
> > AIUI the byte in the partition table that holds 0x83 ("Linux") has no
> > direct relationship to the actual format of the filesystem on that
> > partition, which could be different.  IIRC you set that byte at fdisk
> > time, but the mkfs.blah is done afterwards.  So a partition of type 0x83
> > with VFAT on it is perfectly possible.
> >
> > Did you run mkfs.ext2 -j on /dev/sda1 yet?  If not, then you are looking
> > at the VFAT filesystem, or the first part of it anyway, that shipped
> > with the drive.
> # mkfs.ext3 -j /dev/sda1
> mke2fs 1.38 (30-Jun-2005)
> /dev/sda1 is mounted; will not make a filesystem here!
> =======================
> What I fail to understand is that I expect to have 3 partitions.
> Can I just unmount and mkfs? What about sda2 and sda3? Where are they?

If a partition on the drive is mounted when you repartition it, the
kernel and the drive's partition table will be out of sync, and
subsequent stuff done to the drive will be dubious at best. Better to
unmount everything (eject???), fdisk, *possibly* run udevstart to get
the hal stuff to see the change, format the partitions, and then see
what happens. 

Steve