PhillHS

Q: screen sharing to Linux : xterm problem.

Hi there,

 

We have a user here at the University of Warwick who uses a mac running Yosemite 10.10 (but I have also seen the problem in 10.9). He is using screen sharing to connect to an Ubuntu Linux server running a VNC server. This works fine until he fires up an xterm, when under certain conditions this will cause the session to stop updating.

 

Steps to reproduce :

 

Start xterm, with the mouse pointer over the xterm window, and the xterm window active, start to type, at this point the screen will stop updating. On disconnecting and re-connecting it will be found that any characters typed will have been received by the xterm.

 

What is even stranger is that if you start the xterm, then click on it's title bar to select it as the active window, but then move the mouse pointer so it is*NOT* over the xterm window, any typed characters appear and the terminal interacts as you would expect.

 

Is this a known bug? and is there a work around or fix for it. It seems to be something to do with the xterm attempting to hide the mouse cursor.

 

It should be noted that connecting to the same machine using a vnc client on my windows box does not have the same problem which suggests it's something to do with the interaction between the Linux vnc server and the Mac.

 

Cheers.

 

Phill.

MacBook Pro with Retina display, OS X Mavericks (10.9.1)

Posted on Feb 1, 2016 1:22 AM

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Q: screen sharing to Linux : xterm problem.

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  • by BobHarris,

    BobHarris BobHarris Feb 1, 2016 3:26 PM in response to PhillHS
    Level 6 (19,272 points)
    Mac OS X
    Feb 1, 2016 3:26 PM in response to PhillHS

    Does the problem happen if you use Chicken (as in Chicken of the VNC)?

    <http://sourceforge.net/projects/chicken/>

     

    Chicken may also be a workaround.

  • by etresoft,

    etresoft etresoft Feb 1, 2016 5:32 PM in response to PhillHS
    Level 7 (29,051 points)
    Feb 1, 2016 5:32 PM in response to PhillHS

    Hello PhillHS,

    Why wouldn't they be using X natively?

  • by BobHarris,

    BobHarris BobHarris Feb 1, 2016 8:20 PM in response to etresoft
    Level 6 (19,272 points)
    Mac OS X
    Feb 1, 2016 8:20 PM in response to etresoft

    etresoft wrote:

     

    Hello PhillHS,

    Why wouldn't they be using X natively?

    Speaking from experience, some X11 apps are so chatty that if you are not local to the system (say not local by 2,000 miles), the VNC repainting the screen is faster than passing all the X11 messages back and forth.  Painfully chatty.  And the company I work for does use fast links between the sites.

     

    Of course, my VNC client is the open source vncviewer, which I installed via MacPorts.  It does use XQuartz on my iMac, but that is just the local display, and not the between system X11 traffic (I think vncviewer uses the TightVNC features which repaints only the portions of the screen that have been changed; and is far more network efficient that X11).

     

    But I've also used Chicken, and I did experiment with Screen Sharing, but Screen Sharing years ago did not play nice with 3rd party VNC Servers, so I moved on.  Not sure how well it does today.  I restrict my Screen Sharing to other Mac, where it does very well.

  • by PhillHS,

    PhillHS PhillHS Feb 4, 2016 1:18 AM in response to etresoft
    Level 1 (0 points)
    Feb 4, 2016 1:18 AM in response to etresoft

    Because the user needs a persistent session, that will continue even if they disconnect (they need to set off large downloads that are easiest done using an interactive web browser). X over SSH cannot give them this.

     

    Cheers.

     

    Phill.

  • by moberh,

    moberh moberh Apr 15, 2016 11:47 PM in response to PhillHS
    Level 1 (4 points)
    Mac OS X
    Apr 15, 2016 11:47 PM in response to PhillHS

    I see exactly the same problem, the xterm hang makes Screen Sharing unusable for me. Which is sad, because Retina scaling, keyboard and clipboard work nicely in Screen Sharing, but I cannot avoid xterm on my remotes !

     

    Chicken is also unusable:

    - Remote screens appear way too big on my Retina display

    - Screen artifacts when scrolling on the too-big remote display

    - Frequent disconnects with "Unknown message type 5"

     

    For now I'm using TightVNC in a Virtualbox Ubuntu 14 VM (with "enable HiDPI in VM"), but that's quite slow in the virtual machine ... RealVNC Viewer looks promising, but I'm not exactly sure about its terms ... the Mac viewer-only looks free but is it really free ?

    Still looking for a real solution or workaround !

     

    Macbook Pro 13" early 2015, OS X El Capitan (10.11.3), Screen Sharing version 1.7 (492.39.1).

  • by BobHarris,

    BobHarris BobHarris Apr 16, 2016 9:31 AM in response to moberh
    Level 6 (19,272 points)
    Mac OS X
    Apr 16, 2016 9:31 AM in response to moberh

    but I cannot avoid xterm on my remotes

    Are you using the GUI on the remote, or just xterm sessions?  If just xterm sessions, then ssh from the Mac to the remove.  It far more efficient than X11 or VNC sessions.

     

    Again if xterm sessions only, you could export your xterm to the Mac, assuming the Mac has XQuartz installed

    <http://www.xquartz.org/>

     

    If you are going to use TightVNC, then may I suggest you install XQuartz and then use one of the package managers to install a port of TightVNC on your Mac.  It will locally use XQuartz as its display manager.

     

    Mac package managers are

    Homebrew

    <http://brew.sh/>

    MacPorts

    <http://www.macports.org/>

    Fink

    <http://www.finkproject.org/>


    I use TightVNC on my El Capitan iMac at work connecting mostly to a Linux system in Utah from New Hampshire.

  • by dprall,

    dprall dprall Jul 8, 2016 4:31 PM in response to PhillHS
    Level 1 (4 points)
    Wireless
    Jul 8, 2016 4:31 PM in response to PhillHS

    Same issue for me on a Centos box. Lots of Gnome bugs related to VNC. Had always thought it was a connectivity issue since I tend to do this only when remote. Tried while sitting next to the server and the same thing, wired or wireless. I moved to gnome-terminal and not a single issue anymore. Definitely something with xterm.

     

    I wasn't getting updates back, I could type and type. Disconnect and reconnect and everything I had typed was present. I was using both gnome-terminal for interactive sessions and xterm to start scripted sessions. As soon as I would open one of the xterm sessions everything would hang.

     

    Happened with both Chicken and Screen Sharing. Screen Sharing was just easier to close and restart the session with for me. Have gotten use to it at this point since it is built in.

  • by rccharles,

    rccharles rccharles Jul 9, 2016 5:17 PM in response to moberh
    Level 6 (8,459 points)
    Classic Mac OS
    Jul 9, 2016 5:17 PM in response to moberh

    RealVNC Viewer looks promising, but I'm not exactly sure about its terms


    The client is free.  The server will cost you.  The server runs on the remote box.