Remote X sessions or VNC (was:Re: Headless YellowDog)

[yellowdog-general at lists.terrasoftsolutions.com]

OK, let's beat a dead headless horse.

>  > VNC sessions always run their own X session. But your question here
>  > seems to me to ask, "How do you get access to the VNC server's X
>  > session from the console?"
> 
> 1. This goes a bit to fast for me. Apparently, I'm quite 
> confused about 
> "console" and "virtual terminal". Maybe you can give some 
> clarification 
> on this first ?

By console, I mean the keyboard, the mouse and the monitor. On Linux, you
can get access to several virtual terminals from the keyboard. Alt-F1,
alt-F2 switch between the first two on my PC. Opt-F1, opt-F2 are comparable
on my PowerBook. When X runs, it usually runs on virtual terminal 7. Unlike
switching from a basic bash virtual terminal, switching out from an X
virtual terminal requires three keys: Ctrl-Alt-F1 on my PC or Cmd-Opt-F1 on
my PB.
 
> 2. Then the part about VNC sessions and their own X session: my 
> experience here seems to contradict this. Let me explain.
> My setup is:
> aragorn: server machine in the basement, with an active KDE 
> session on 
> vt7, in this session, I have started a program called 
> x0rfbserver (which 
> gets started by the mandrake's menu option "Virtual Network 
> Connection).
> On g3ydl, I have an active KDE session on vt7 in which I start YDL's 
> Remote Desktop Connection. The window I get, is the exact 
> screen of the 
> system in the basement, and when I move the mouse, or type something, 
> the exact same movements and keys strokes are seen on the 
> screen in the 
> basement. So it seems to me the same X session is shared in 
> this case. 
> My guess is we're talking about different vnc servers. Is x0rfbserver 
> something particular ?

The email I sent out before tries to clarify this. Your experience is with
the VNC module of the X server acting as a Remote Desktop interface to the
running X session on the console. The usual, stand-alone vncserver runs X
inside-out compared to Remote desktop. As you say below, what you want is
vncserver. Not the VNC module of the X on the console.
 
> In any case, this setup is not what I want, since it forces 
> me to first 
> start a kde session sitting in front of my aragorn box in the 
> basement, 
> starting the Virtual Network Connection menu item, and when this one 
> crashes (happens consistently if I dare to use the scroll 
> wheel in the 
> vnc client on g3ydl) I have to go to the basement again...

Right. This is a pain in the rump. Just use vncserver and it will fire up
its own X session under it. It will start up with the system RC scripts. It
has access to all the right stuff to get your bits sprayed to g3ydl and
you'll never have to trip over crap left on the basement stairs ever again.
 
> 3. So my curiosity goes out to vncserver you are referring 
> to. Is this 
> TightVNCserver (the only one I found in my Mandrake setup) ?

Maybe. I dunno. Prolly.

>  > Well, you can't if you're just using
>  > "vncserver", but if you just start up another X session on 
> the console
>  > that uses the VNC module, you'll be able to do it. Then 
> you'd just VNC
>  > to foomachine:1 instead of foomachine:0.4.
> 
> 4. "Another X session that uses the VNC module"... Do you 
> mean then, as 
> in your faq, that on the local machine, I type 'X :1' to get a new X 
> session on VT8 ? And next, I don't understand about the VNC 
> module part.

Remember, I was trying to answer the question of how you'd be able to use a
different VNC session other than the console. The above took care of that, I
hope, In any event, I hope by now it's clear that, yes, you can run another
X server on your console and it will take its place in the next available
virtual terminal slot. If and only if your X session also takes advantage of
the VNC module, you'd be able to use a vnc client to to view that desktop.
This is all moot because you *really* don't want to hassle with running
another X session on the console just so you can VNC into it.
 
> 5. In the last sentence, how can I tell the vncviewer to use display 
> foomachine:1, instead of foomachine:0.4? Is this by starting 
> vncviewer 
> on the command line,after having set the DISPLAY variable ?

Should be foomachine:1 instead of foomachine:0. It depends on the client.
Most allow you to supply it on the command line.

WHOA, WHOA, WHOA! Don't even talk about the DISPLAY variable here. The
vncviewer client will just run. It will pop up in your X session. You
shouldn't have to tell it anything special. If you're running an xterm, it's
already got the correct DISPLAY set so you don't have to do anything. Don't
mess, man, don't mess.
 
> Forgive me, if all of these questions seem hopelessly obvious 
> to you. My 
> experience with limited to the GUI wrappers that YDL and Mandrake 
> provide. And those, of course, don't help at all in undertanding what 
> goes on under the hood.

That's the biggest drawback to GUI's in my mind. It shields too much of the
underpinnings. They're handy because you can do so many things at once but
the administration goes way up because of all the learning you have to do.
Not so much learning, as poking and digging to find the answers.

> 6. Finally, is there some good reference documentation 
> available for VNC 
> ? That way once I got started, I don't have to overload the list here.

The man page and Google are my best friends. Besides my dog, that is.