Thumbdrive permissions, mounting, executables

[strask]

mark@Lexington-19:/$ sudo umount /LEXAR
[sudo] password for mark:
mark@Lexington-19:/$ sudo mount /LEXAR
mount: mount point /LEXAR does not exist

That is Bizarre! Why is the /LEXAR directory going away?

If you recreate it (sudo mkdir /LEXAR) does the mount command succeed? If you then repeat the umount/mount does the directory disappear again? I am so confused.

please know that the thumbdrive, named LEXAR does not appear in the panel's drop down menu. All this mount/umount should have it showing as: LEXAR.

I cannot find an object (folder, device, etc.) in neither / nor /home - nor in /etc but there is, in /media a LEXAR. I can't open that folder as non-root-user. As root, it opens, but appears empty.

That all sounds normal to me, nothing to worry about as long as we can get the mounting and unmounting to behave consistently. Once it's working you can add a shortcut to your panel pointing at /LEXAR and that will make things easy.

PS - fstab w/o added /sdc1 & uuid is backed up within /etc

Excellent.

Since the umount/mount commands didn't complain about fstab errors I don't think we will need that backup, but keep it around just in case.

[Mark_in_Hollywood]

mark@Lexington-19:/$ sudo mkdir /LEXAR
[sudo] password for mark: [terminal returned]
mark@Lexington-19:/$


mark@Lexington-19:/$ sudo mount LEXAR

Thunar shows /LEXAR in /


mark@Lexington-19:/$ sudo umount LEXAR

Thunar shows NO /LEXAR in /

==== a few moments later ======

just playing with it:

mark@Lexington-19:/$ sudo mount LEXAR
mount: can't find LEXAR in /etc/fstab or /etc/mtab

I hope this helps.

[strask]

You need to put the slash at the front, so /LEXAR not LEXAR.

That still doesn't explain why the mount point is being removed every time we unmount.

What version of Ubuntu are you using? I am on Ubuntu 12.04; I'm starting to wonder if you are on an old version with a bug or something. I'm seriously confused about this.

[Mark_in_Hollywood]

Sorry, this is Precise Pangolin v. 12.04 LTS. But, for what it's worth, I've always had trouble mounting/unmounting USB drives, whether Seagate 3.5" drives in an external cradle, or simpler USB thumbdrives.

Please know that the thumbdrive, named LEXAR, until I started trying to fix this mess, is plugged into the usb hub port.

It has semi-critical data on it and as I have this device in a risky place, I would like to see the data that is on it, before I mess something up.

[strask]

Ok I found the bug : https://bugs.launchpad.net/ubuntu/+s...ks/+bug/498423

I'm not positive, but it looks like it should not be a problem after we reboot, as long as you are leaving the drive plugged in all the time. If you hotplug the drive, then use manual commands to mount it on /LEXAR again, then umount it, it will continue to delete the mount point.

It has semi-critical data on it and as I have this device in a risky place, I would like to see the data that is on it, before I mess something up.

Absolutely. To see the data on the drive, just recreate the mount point and mount it again:

sudo mkdir /LEXAR
sudo mount /LEXAR

That assumes we still have the new line in the fstab. Once mounted, just browse to /LEXAR in your file manager or whatever to reassure yourself that your data is safe.

Edit: This is annoying, but actually before rebooting unmount it again (sudo umount /LEXAR) which will delete the mount point, then make the mount point again (sudo mkdir /LEXAR) and DON'T mount it, THEN reboot. That should be the last time you have to type manual commands.

[Mark_in_Hollywood]

Upon reboot (warm boot), LEXAR exists in / - and sesame can be executed and it properly authenticates.

But where is the thumbdrive? It's not on in the panel drop down list.

lsusb shows:

Bus 001 Device 009: ID 05dc:a769 Lexar Media, Inc.

but since both the folder from sudo mkdir /LEXAR and the usb drive have the same name, "LEXAR", something is amiss. And I hope I'm not getting ahead of you here. But I'm somewhat lost in what we're doing.

and
sudo fdisk -l shows:

Disk /dev/sdd: 3942 MB, 3942645760 bytes
122 heads, 62 sectors/track, 1018 cylinders, total 7700480 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0008884e

Device Boot Start End Blocks Id System
/dev/sdd1 62 7700151 3850045 c W95 FAT32 (LBA)

do I have to edit /etc/fstab to reflect that the thumbdrive is now called: /dev/sdd?

[strask]

Upon reboot (warm boot), LEXAR exists in / - and sesame can be executed and it properly authenticates.

Excellent. I fully expect that to continue to work for you forever now.

But where is the thumbdrive? It's not on in the panel drop down list.

The /LEXAR folder IS your thumbdrive. It just doesn't look so much like a thumb drive now. The icon or appearance may have changed (we don't use the same desktop environment, so I'm not sure what yours looks like) but it's exactly where it is supposed to be.

You can create a shortcut in Thunar or whatever to make it simple to click over to /LEXAR in the future.

If you need to safely remove the drive while the system is running, just use

sudo umount /LEXAR

and once it's unmounted, it's safe to remove.

[strask]

do I have to edit /etc/fstab to reflect that the thumbdrive is now called: /dev/sdd?

No, because we used the UUID to specify it in the fstab, you don't need to worry about the drive letter changing.

[Mark_in_Hollywood]

A few more moments, please.

Upon

sudo umount /LEXAR

and using the file manager to see /

LEXAR appears. Should it, if it's unmounted? (worry-wart-me)

and

Please see the attached screenshot, left side frame, where you can see 3 other usb thumbdrives, but not LEXAR. It used to appear in that list. But even after sudo mount /LEXAR it's not to be seen. Is this critical?

... a few moments later:

mark@Lexington-19:/LEXAR$ sudo umount /LEXAR
umount: /LEXAR: device is busy.
(In some cases useful info about processes that use
the device is found by lsof(8) or fuser(1))
mark@Lexington-19:/LEXAR$

and it will not unmount.

Maybe we should call it quits for now, but the whole point of having the linux executable on a removeable device is to prevent computer use unless it's plugged in. The 'system' is a 2-step authentication, requiring 2 passwords, but one must be generated from the thumbdrive executable. If I can't remove the thumbdrive and take it to another computer, I've defeated the purpose LastPass.

[strask]

sudo umount /LEXAR

and using the file manager to see /

LEXAR appears. Should it, if it's unmounted? (worry-wart-me)

Yes that's exactly what we want; that folder needs to stick around so that it mounts correctly at boot time. It will just be empty if the drive isn't mounted.

Please see the attached screenshot, where you can see 2 other usb thumbdrives, but not LEXAR. It used to appear in that list. But even after sudo mount /LEXAR it's not to be seen. Is this critical?

Not at all critical. Possibly a minor inconvenience for you, but much less of an inconvenience than needing to type mount commands every time you boot.

The list of thumb drives that you show in that screen shot is a list of drives that the system mounted automatically when plugged in, but that were not listed in the fstab. It won't list drives that you mount with manual mount commands, because those aren't automatic. And it won't list drives that you put in the fstab. That's just kind of the way it works.

Like I said before, you should be able to add a shortcut to your file browser to make /LEXAR show up on your left-hand navigation pane; I use a different file manager though so I'm not sure of the exact steps. But even if you add that shortcut, the icon won't look like a thumb drive... just a folder.