RE: Preventing X server resets

[Jean-Claude Gervais <jc dot gervais at videotron dot ca>]

Hi,

	Would xmove also be a possibility?

	From what I understand, xmove can be used to disconnect an X session from a
host without the session actually closing.

	You can then "move" the display to another machineand resume where you left
off.. You can also simply reattach to the X session from the machine that
originally requested it.

	Is that what you're after?


-----Original Message-----
From: cygwin-xfree-owner@cygwin.com [mailto:cygwin-xfree-owner@cygwin.com]On
Behalf Of Rasjid Wilcox
Sent: Friday, November 15, 2002 6:08 PM
To: cygwin-xfree@cygwin.com; Oliver, Peter; 'cygwin-xfree@cygwin.com'
Subject: Re: Preventing X server resets

On Sat, 16 Nov 2002 2:41 am, Oliver, Peter wrote:
> I'm using XDMCP for my session, from where I run X applications on
> various different servers.  If the machine I logged onto with XDMCP is
> rebooted, or suffers network difficulties, the X server resets and I
> loose my whole session.  I would prefer the X server and it's remaining
> clients to continue running, so that I can just start a window manager
> on a different box and carry on working.  Is there some way to prevent
> this reset from happening?  I gave the -noreset option a try but it made
> no difference.

As other posts have indicated, you can't solve this with XDMCP.  The only
(open source) solution that I'm aware of is to use VNC.  There are several
different VNC versions out there.  http://www.realvnc.com is the new version
by the original developers.  (There is also Tridia VNC, Tight VNC, esVNC and
probably others.)

This adds an extra layer between the user and the applications.  In essence
VNC runs a virtual X-Server on the machine running the applications.
(Actually, it could be some other machine, but lets keep this simple.)  To
illustrate, suppose you have a machine 'Server', and a machine 'Desktop'.
The user is sitting in front of 'Desktop', and the applications live on
'Server'.

With XDMCP:

  Process                   Machine
Application A                Server
     |
     | X Protocol
     |
 X-Server                    Desktop


With VNC:

  Process                    Machine
Application A                 Server
     |
     | X Protocol
     |
 VNC Server                   Server
     |
     | VNC Protocol
     |
 VNC Client                   Desktop
     |
     | X Protocol
     |
 X-Server                     Desktop

If the 'Desktop' is running Windows, you don't need the last step, since
there
is a native Windows VNC Client.

The advantage with VNC is you can kill the VNC client and not lose you
X-Session.  You can for example, log in at work (using VNC), leave stuff
running but kill the VNC client, go home, and re-connect with a new VNC
client at home, and still be running the original session you left going at
work.

The disadvantage (over a LAN) is the 'smoothness' of the display, although I
believe the new versions are pretty good.  You also can't use XDMCP, so no
nice login screen.  But for keeping an X-Session going even when your
desktop
crashes, it is just what the doctor ordered.  (VNC is also useful for low
bandwidth connections.)

Anyway, since there is a Win32 VNC Client (and server), this is not somewhat
offtop for this list.  OTOH, I wonder what the performance of the *nix vnc
client would be under XFree-Cygwin?  Might have a look sometime.

Cheers,

Rasjid.