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Thread: Question about Reading and Understanding System Log Ubuntu 20.04

  1. #1
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    Question about Reading and Understanding System Log Ubuntu 20.04

    Hi there,
    I have some basic questions about some of the info in my recent system logs of Ubuntu 20.04. Though I did some research on knowledgeable websites, some of the explanations can get to be too technical, so I'd be grateful for some simple, clarifying answers from a knowledgeable person. My questions are about a laptop that is *not* connected to the internet, as I have a second laptop that I use online.
    Here goes:
    -Is it normal for the virtual filesystem service to start on login? I do not have VPN and, as I said, this is a laptop not connected to the internet;
    -What does "stopped manager wait online" mean? Is it a program that always starts up on any Ubuntu 20.04 or only if you are trying to make a connection to the internet or to a server?
    -What does "supervising 4 threads of 2 processes of 2 users mean"? Who or what is the second user besides the local user, me?
    -What does "Activity service name="org.gnome.OnlineAccounts" requested by ':1.9'" refer to?
    -What is "X server :0.NL"?
    Thanks for your time.
    Last edited by bhubunt; December 3rd, 2021 at 09:06 PM.

  2. #2
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    Ubuntu Development Release

    Re: Question about Reading and Understanding System Log Ubuntu 20.04

    I will have a go. Or, at least start off the discussion. And a discussion is what this thread will turn into.

    -What does "supervising 4 threads of 2 processes of 2 users mean"? Who or what is the second user besides the local user, me?
    There are always two users. Root and Me. Whoever Me is. In your case Me is you. In my case Me is me, myself. Have you not noticed that you (the user) do not get involved until after Linux has loaded and in turn loaded a display manager that presents on the display a login screen? Root had the authority to do all that.

    -What is "X server :0.NL"?
    In Linux X is the video server. Hence X-Server. It has been around for years but is being replaced by video servers or compositors built according the Wayland protocol. With Ubuntu 20.04 we get the option at login to select either X-Server or Ubuntu on Wayland. The system defaults to X-Server. From Ubuntu 21.04 onwards Wayland is the default with the option to load Ubuntu on X-Server.

    The ":0.NL" part refers to the display number. One display = :0. As for "NL" I can only guess.

    so I'd be grateful for some simple, clarifying answers from a knowledgeable person
    That is asking a lot. The more knowledge a person has the harder it is to give simple, clear answers.

    Regards
    It is a machine. It is more stupid than we are. It will not stop us from doing stupid things.
    Ubuntu user #33,200. Linux user #530,530


  3. #3
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    Re: Question about Reading and Understanding System Log Ubuntu 20.04

    Thanks very much for your quick and knowledgeable reply.

    Can I ask a follow-up question about this quote:

    Quote Originally Posted by grahammechanical View Post

    In Linux X is the video server. Hence X-Server. It has been around for years but is being replaced by video servers or compositors built according the Wayland protocol. With Ubuntu 20.04 we get the option at login to select either X-Server or Ubuntu on Wayland. The system defaults to X-Server. From Ubuntu 21.04 onwards Wayland is the default with the option to load Ubuntu on X-Server.

    The ":0.NL" part refers to the display number. One display = :0. As for "NL" I can only guess.
    I am still not clear about what the function of the video server is. I did a quick google search and most posts refer to it for live streaming on the web.

    Regards.

  4. #4
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    ozarks, Arkansas, USA
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    Xubuntu 20.04 Focal Fossa

    Re: Question about Reading and Understanding System Log Ubuntu 20.04

    bhubunt; Hello

    Please allow me to introduce you to the package manager.
    what the function of the video server is
    In your terminal execute the command:
    Code:
    apt show xserver-xorg-video-nouveau
    where here the example is the nouvea driver for Nvidia cards.
    to see what your video device is, run:
    Code:
    sudo lshw -C display
    and make the suitable substitution for "nouvea".

    Then we can continue this discussion.

    my bit to try and help
    THE current(cy) in Documentation:
    https://help.ubuntu.com/community/PopularPages

    Happy ubuntu'n !

  5. #5
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    Re: Question about Reading and Understanding System Log Ubuntu 20.04

    Quote Originally Posted by bhubunt View Post
    -Is it normal for the virtual filesystem service to start on login? I do not have VPN and, as I said, this is a laptop not connected to the internet;
    The Virtual File System service has nothing in common with a Virtual Private Network except the word "Virtual". It's purpose is to make things that are not really file systems look like they are. An example would be a connection through USB to your phone for transferring files. It looks like a mounted file system but is actually a connection using the Media Transfer Protocol. There are quite a few other things like that.
    Quote Originally Posted by bhubunt View Post
    -What does "Activity service name="org.gnome.OnlineAccounts" requested by ':1.9'" refer to?
    The Gnome Desktop Environment has a component for managing all your online accounts (user names, passwords ...). When Gnome starts, this component gets started. It's a rather deeply integrated into the rest of the system and I don't know of a way to use Gnome and not have it around.
    Quote Originally Posted by bhubunt View Post
    I am still not clear about what the function of the video server is. I did a quick google search and most posts refer to it for live streaming on the web.
    Actually it's not a video server it's the display server. It sits between the user's input devices and display and the application programs. You can find an overview of X on Wikipedia.

    Holger

  6. #6
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    Re: Question about Reading and Understanding System Log Ubuntu 20.04

    Bashing-Om, Thanks very much for the command lines. I will definitely get to it later today.

    * * *

    Holger, Thanks very much for the following explanation:

    Quote Originally Posted by Holger_Gehrke View Post
    The Virtual File System service has nothing in common with a Virtual Private Network except the word "Virtual". It's purpose is to make things that are not really file systems look like they are. An example would be a connection through USB to your phone for transferring files. It looks like a mounted file system but is actually a connection using the Media Transfer Protocol. There are quite a few other things like that.
    Pardon me for asking for further clarification: the media transfer protocol also showed up in the system log. Is that just because services like the virtual file system and the media transfer protocol get activated any time I boot ubuntu 20.04 or would I have to execute a specific action/command for them to get activated?

    Regards to all

  7. #7
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    Re: Question about Reading and Understanding System Log Ubuntu 20.04

    Hi all,

    I just combed through some of my system logs again and found more of the following:

    -Leaving MDNS multicast group on interface lo.IPv4 with address 127.0.0.1
    -Stopped Network Manager wait online
    -Stopped Network Name Resolution
    -Stopping WPA Supplicant (Wifi Protected Access)

    And I found several references to local service cookies (or authentication cookies)

    The lines read:
    Server startup complete [name of my laptop] local service cookie [number]

    This to me looks like my laptop connected to a server?
    Last edited by bhubunt; December 4th, 2021 at 08:52 PM.

  8. #8
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    Re: Question about Reading and Understanding System Log Ubuntu 20.04

    127.x.x.x in IP4 is the loopback interface. It's there for the machine to 'talk to itself'. For example all printing goes through that 'network'. The advantage to this should be obvious: as far as the rest of the system is concerned, there's no difference in printing to a locally connected printer or a remote one. A lot of subsystems on a Linux machine are like this, up to and including the GUI: the X-server can take request and send responses from and to other machines; that way you can have a program running on one machine and displaying it's GUI on another.

    Holger

  9. #9
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    Re: Question about Reading and Understanding System Log Ubuntu 20.04

    Thanks for the info about the loopback interface. But I have no printer attached to the laptop nor any other machine. The laptop I am using is not connected to the internet.

    That is why I am interested in knowing more about the other parts of my query: the reference to the MDNS multicast group and especially the cookies in my system logs:

    Quote:
    ""And I found several references to local service cookies (or authentication cookies)

    The lines read:
    Server startup complete [name of my laptop] local service cookie [number]

    This to me looks like my laptop connected to a server?"
    Last edited by bhubunt; December 4th, 2021 at 10:38 PM.

  10. #10
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    Re: Question about Reading and Understanding System Log Ubuntu 20.04

    Even if you have no printer connected and no printer driver installed the printing system is installed and - probably - running. Try opening http://localhost:631 in a browser. You should get connected to the CUPS (Common Unix Printing System) web-frontend on your machine.

    MDNS is a system for machines to find each other on a network without having a dedicated server just for connecting IP-addresses and hostnames, similar to Microsoft's Zeroconf and Apple's Bonjour. On the loopback interface this system doesn't make much sense (you won't find other machines on that network), so it left the multicast group for it.

    Cookies aren't limited to the web. The small bit of data the X-Server gives you as identification is called a cookie, too. You can see it with 'xauth list' (you'll probably get more than one, because there's more than one way a program can connect to the X-Server).

    The (abstract) connection between your user session (the collection of all the programs running under your account at a given time) and the OS is also managed with a cookie generated through PAM. PAM stands for Pluggable Authentication Modules and is the part of the system which gets your username and password from whatever you use to login and returns either OK and a cookie or not OK (and no cookie for you ...) to the program trying to log you in. This might be the text based 'login' or the greeter part of the graphical login ... And of course - as the name implies - this is a modular system and there are modules which will hand off the username/password combo to a server on your network for checking so you can have the same username and password across all machines on your LAN and possibly also get a home directory mounted from some file server so you have the same working environment no matter from which of your machines you login.

    If you run some administrative commands with 'sudo', you'll find notices in your logfile about the system starting another session for 'root' as the administrator account is called on Unix-like Systems. And 'sudo' also uses a cookie to see whether that session has timed out and it needs to ask for the password again.

    So yes, you are on a network ... with exactly one node which is acting as both server and client.

    Holger

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