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  • /dev/sde: open failed: No medium found

    From Doug Laidlaw@2:250/1 to All on Sun Apr 26 10:46:31 2020
    For a long time, I have seen lines like the above when updating grub2.
    There used to be only one occurrence; now there are several. Needless to
    say, /dev/sde is not shown by the "df" command.

    There is such a device:

    ll /dev/sde
    brw-rw---- 1 root disk 8, 64 Apr 26 18:43 /dev/sde

    It is only a nuisance message, but I would like to know why it is there
    at all. I would have expected that if there was no such medium, it
    would have been ignored.

    TIA,

    Doug.

    --- MBSE BBS v1.0.7.13 (GNU/Linux-x86_64)
    * Origin: Aioe.org NNTP Server (2:250/1@fidonet)
  • From Jim Beard@2:250/1 to All on Sun Apr 26 14:19:30 2020
    On Sun, 26 Apr 2020 19:46:31 +1000, Doug Laidlaw wrote:

    For a long time, I have seen lines like the above when updating grub2.
    There used to be only one occurrence; now there are several. Needless to say, /dev/sde is not shown by the "df" command.

    There is such a device:

    ll /dev/sde
    brw-rw---- 1 root disk 8, 64 Apr 26 18:43 /dev/sde

    It is only a nuisance message, but I would like to know why it is there
    at all. I would have expected that if there was no such medium, it
    would have been ignored.

    TIA,

    Doug.

    brw-rw---- 1 root disk
    Owner is root and user is disk, so this is read-write only for root
    and disk appearing in /etc/passwd and /etc/group. If an ordinary user,
    you would not see it or be able to access it.

    If sde were a directory, absence of the execute bit would mean it
    could not be searched, but I am not sure this matters as mounting
    sde could change that.

    Custom settings in group and passwd could change things, of course.

    Cheers!

    jim b.

    --
    UNIX is not user-unfriendly, it merely expects users to be computer-friendly.

    --- MBSE BBS v1.0.7.13 (GNU/Linux-x86_64)
    * Origin: A noiseless patient Spider (2:250/1@fidonet)
  • From Bit Twister@2:250/1 to All on Sun Apr 26 14:40:00 2020
    On Sun, 26 Apr 2020 19:46:31 +1000, Doug Laidlaw wrote:
    For a long time, I have seen lines like the above when updating grub2.
    There used to be only one occurrence; now there are several. Needless to
    say, /dev/sde is not shown by the "df" command.

    There is such a device:

    ll /dev/sde
    brw-rw---- 1 root disk 8, 64 Apr 26 18:43 /dev/sde

    It is only a nuisance message, but I would like to know why it is there
    at all.

    My guess, new and improved grub is now checking/finding usb or memory
    card devices.

    I see the messages during boot. A quick look at my hardware gives
    # hwinfo | grep /dev/sg | grep Device | sort
    Device File: /dev/sdc (/dev/sg3)
    Device File: /dev/sdd (/dev/sg4)
    Device File: /dev/sde (/dev/sg5)
    Device File: /dev/sdf (/dev/sg6)
    Device File: /dev/sr0 (/dev/sg2)
    which are usb and memory card slots and cd/dvd drive.

    I would have expected that if there was no such medium, it
    would have been ignored.

    If no such message was issued, how would you know if there was a problem
    if you were wanting grub to use the device?


    --- MBSE BBS v1.0.7.13 (GNU/Linux-x86_64)
    * Origin: A noiseless patient Spider (2:250/1@fidonet)
  • From Doug Laidlaw@2:250/1 to All on Sun Apr 26 14:43:58 2020
    On 26/4/20 11:19 pm, Jim Beard wrote:
    On Sun, 26 Apr 2020 19:46:31 +1000, Doug Laidlaw wrote:

    For a long time, I have seen lines like the above when updating grub2.
    There used to be only one occurrence; now there are several. Needless to
    say, /dev/sde is not shown by the "df" command.

    There is such a device:

    ll /dev/sde
    brw-rw---- 1 root disk 8, 64 Apr 26 18:43 /dev/sde

    It is only a nuisance message, but I would like to know why it is there
    at all. I would have expected that if there was no such medium, it
    would have been ignored.

    TIA,

    Doug.

    brw-rw---- 1 root disk
    Owner is root and user is disk, so this is read-write only for root
    and disk appearing in /etc/passwd and /etc/group. If an ordinary user,
    you would not see it or be able to access it.

    If sde were a directory, absence of the execute bit would mean it
    could not be searched, but I am not sure this matters as mounting
    sde could change that.

    Custom settings in group and passwd could change things, of course.

    Cheers!

    jim b.

    Thanks, Jim. I assume that the "b" means a block device. Coming from Windows, I am amazed that there are so many system user accounts in
    Linux. In Windows, we were told that unnecessary accounts only use up
    RAM, but Linux has more of them than Windows ever did.

    [Wikipedia says that block devices were abolished in Linux and FreeBSD,
    then in the next sentence, says that they still exist in Linux. In
    these situations, I simply do what I am told, as I said when telling
    Pinnerite that he needed "devel" packages when compiling from source.
    Bill Unruh gave the "why," but it doesn't have any impact on my procedures.]

    Doug.

    --- MBSE BBS v1.0.7.13 (GNU/Linux-x86_64)
    * Origin: Aioe.org NNTP Server (2:250/1@fidonet)