[PLUG] USB flash drive issues

[Rich Shepard]

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.

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.

Both hosts run the same distribution: Slackware-14.2.

What should I read to learn why the kernel in the new system is giving me
such a hard time with both this SunDisk flash drive and another one when the
other desktop has no issues with either.

TIA,

Rich

[Rich Shepard]

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.

Wes,

The fstab entries on both systems are the same: auto,users.rw.

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.

True. But what I want to understand is why the source system understands
that both problem flash drives have a vfat file system while the target
system doesn't.

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

Will do so tomorrow.

Rich

[Ben Koenig]

Verify that the default behavior in Slackware works before adding your
customizations. Instead of jumping to the fstab line and creating a new
folder, try the following command, as root.

mount /dev/sdc1 /mnt/hd


/mnt/hd is part of a default slackware installation, I use for quick manual
mounts to avoid issues that can arise with bad permissions. It will be an
emptry direction unless you put something in there.
If running the above mount command works, then you know your fstab
configuration is faulty.

If it fails, then there is either a problem with your Slackware install or
a hardware driver.

Also, and I learned this just now, /proc/filesystems has a list of
available filesystems for the -t option, according to 'man mount'.

Post by Rich Shepard

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.

Wes,
The fstab entries on both systems are the same: auto,users.rw.

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.

True. But what I want to understand is why the source system understands
that both problem flash drives have a vfat file system while the target
system doesn't.

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

Will do so tomorrow.
Rich
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