Removable media behaviour

Joao Pedro Clemente jpcl at
Thu Apr 20 00:10:29 BST 2006

Hi all. I think this issue is generic to (k)Ubuntu, if you dont want to
discuss it here, well, I've tried. (Do you think I should move it to other
Mailing list? Which one?)

I was testing the behaviour of removable media handling (usb memory pen)
and if I would like to propose one of these things, wich I think are

a) that usb pen (removable media) get mounted with "sync" option. It would
avoid data loss if the user plugs it out.

if this is not reasonable because "one must educate users", then, at

b) that usb pen (removable media) get synced/umounted automatically on
user logout. There are various reasons for me to accept this one:
 - I taugth the user that it must logout. The session ended, so its data
must be flushed. Seems logic to me.
 - It would solve the problem of someone logging out with an inserted pen,
and then log in as another user. If my tests were correct, the cenario I just
described will prevent the 2nd user to use the pen drive as it is mounted
with 1rst user permissions.

If I understood the behaviour of removable media with (k)ubuntu, it is
now like this:
 Step 1 - The user plugs in the memory pen.
 Step 2 - The system detects the plug
   -  IF there is a user "A" logged, the pen will be mounted for user "A".
   -  IF not, the system does nothing untill some user logs in. So, when
user logs in, the system also checks "hum, was there a media insertion
that is unassigned? Let me assign it now to the user that is logging in"
 Step 3 - The user logs out. System does nothing

The thing is, if these steps are taken, and if some other user logs in, we
have a problem. The problem is that the media is "assigned" to an user
that is not the one using the machine. So, the new user:
 - Cannot eject the cd-rom
 - Cannot umount the pen-drive
 - Cannot write to the currently existant pen-drive (it has no
permissions) - actually it cannot even read the pen contents!
 - Cannot go around this by plugging the pen out and in again, as this
would make it lose the data (modified by the previous user) that is still
not synced.

Have I explained myself? Do you need me to detail the test procedure to
reproduce this problem? Does it seem of any importance? What do you people
think about this?

Thanks for you time!

		        	Joao Pedro Clemente
        			jpcl @
					(when not working out)
					(when not sleeping)
					(when not surfing)
					(when not ... ;)

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