[PLUG] USB flash drive issues

[wes]

On Wed, Sep 26, 2018 at 3:42 PM Rich Shepard <rshepard at appl-ecosys.com>
wrote:

>    These issues are out of my knowledge base on USB flash drives and I
> need someone to explain some unusual behavior to me, or point me to docs
> that explain mounting removable media.
>
>    Setting up my new desktop I need to copy config files from the existing
> server/workstation to the new one, and I'm using USB flash drives for this.
>
>    One drive I used was recognized by both systems as /dev/sdc. A different
> drive (a 32G Sundisk) was seen by the existing host as /dev/sdb1 (which is
> in fstab as: /dev/sdb1   /mnt/thumb  vfat  auto,users,rw  0   0)
>
>    The new host sees it as sdc/sdc1, so I made a mount point /mnt/flash/
> and
> entered it in /etc/fstab as: /dev/sdc1   /mnt/flash   vfat   auto,users.rw
> 0
> 0).
>
>    When I try to mount /mnt/flash the system tells me only root can mount
> it.
> This is one aspect I don't understand.
>

Normally, only the superuser ("root" on many unix-like operating systems)
can mount a new filesystem. This is not required on your older system
because you've specified the "users" option in the related fstab entry.


>    When root tries to '/mount /dev/sdc1 /mnt/flash' the system tells me
> it's
> the wrong filesystem type -- not vfat -- and it cannot find the superblock.
> This is another aspect I don't understand.
>

This is the expected behavior when the mount utility is unable to identify
what it's mounting. Normally, if you don't specify the filesystem type, it
tries to detect it for you. If you do specify the type, and the actual type
on the storage device is not the same as what you specified, you'll get the
same error.

You may want to try using the "file" and "fdisk" utilities on the device
paths to see what may actually be there.

sudo file -s /dev/sdc
sudo file -s /dev/sdc1
sudo fdisk -l /dev/sdc

and so on.

-wes