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<div class="moz-cite-prefix">On 01/21/2014 10:25 PM, Aruna
Hewapathirane wrote:<br>
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<blockquote
cite="mid:CAFSeFg-OpWUNvU91D9Eq+eeB+2BSeewUmzFeeM6QFu+azBMoqg-JsoAwUIsXotQFR93xxRIaA@public.gmane.orgcom"
type="cite">
<div dir="ltr">I was testing window managers and having a hard
time comparing each due to constantly having to log-off and sign
back in as another user with a different window manager and then
something sweet happened. I came across a article and now I am
flipping back and forth between virtual terminals that have
gnome-classic, LXDE, Openbox and Awesome and it's amazing.<br>
<div><br>
</div>
<div>The article is here: <a moz-do-not-send="true"
href="http://www.doknowevil.net/2010/10/13/multiple-x-desktop-sessions-in-ubuntu/"
target="_blank">http://www.doknowevil.net/2010/10/13/multiple-x-desktop-sessions-in-ubuntu/</a><br>
</div>
<div>
</div>
<div>and for those of us who are lazy the content is right
below, seriously you should try this it blew me away :)<br>
</div>
<div><br>
-------------------------------------------------------------------------------------------------------------------------------------------<br>
This post has a lot to do with graphics but there are no
graphics. It’s a walk-through explanation and and proof of
concept of some very interesting features of Linux as a
desktop operating system.
<div>
<p>If you aren’t familiar with X, <a moz-do-not-send="true"
href="http://www.x.org" title="X.org" target="_blank">than
this webpage might confuse you</a>, the <a
moz-do-not-send="true"
href="http://en.wikipedia.org/wiki/X_Window_System"
title="X11 Window System" target="_blank">X Window
System</a> is what draws the GUI (graphical user
interface) for Ubuntu. On top of this, you may have a <a
moz-do-not-send="true" href="http://xwinman.org/"
target="_blank">Window Manager or Desktop Environment</a>,
such as Gnome (Ubuntu default) or KDE (Kubuntu).</p>
<p>When you boot up Ubuntu, it creates a set of “virtual
terminals”. These VTs are accessible via a key combination
of clt+alt+f1-12. VT7 (ctrl+alt+f7) is the default and it
handles X’s “screen 0″. If you play around, with the key
combination, you’ll notice you drop into consoles with a
login prompt (f1-6) or a blank screen (f8-f12, <a
moz-do-not-send="true"
href="https://bugs.launchpad.net/ubuntu/+source/linux/+bug/256767"
target="_blank">don’t worry if you see USB errors</a>).
</p>
<p>These virtual terminals used to be handled by X which was
slower and more prone to crash (citation needed) but since
Ubuntu 8.04, this has been handled by “<a
moz-do-not-send="true"
href="https://wiki.ubuntu.com/X/KernelModeSetting"
target="_blank">Kernel Mode”</a>, where this management
is handled by the kernel. You can switch to another
virtual terminal and create another X session.</p>
<p>Typically in Linux, you could switch to another VT, login
[as another user] and type $ <b>startx — :1</b> (special
argument ‘<code>--</code>‘ marks the end of client
arguments and the beginning of server options, :1 defines
screen 1). This will work in Ubuntu but the part where I
found it failing was switching between this newly created
X session and back to my original :0 on VT7.</p>
<p>The way I found to do this in Ubuntu seems a bit
counter-intuitive. Before I explain, you should create a
new user, if you don’t have another already. You can do
this by going to System > Administration > Users and
Groups.</p>
<p>To create a second X session in Ubuntu, go to your logout
menu (default top right) and select “switch user”, and
login as another user (you don’t want to create an error
in the user environment). When you login as another user,
Ubuntu creates a screen :1 on VT8. This means, you can
change back to VT7 with ctrl+alt+f7, then back to VT8 with
ctrl+alt+f8. I <i>suspect</i> this is the reason VT8-12
show up as blank screens instead of login terminals.
Ubuntu seems to be leveraging the power of virtual
terminals for “user switches”.</p>
<p>I haven’t noticed much in performance loss doing this and
the other big question is practicality. Why would you ever
do this? Perhaps you are testing software and want
isolated test cases or you want a dedicated user for games
with a more streamlined window manager and want to be able
to flip back and forth.<br>
</p>
<div>-------------------------------------------------------------------------------------------------------------</div>
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</blockquote>
We use this method at home daily for one simple task. My wife and I
each have our own profile the first one to log on gets VT7, the next
gets VT8. She switches to her profile using 'switch user', my
prederence is ctrl+alt+f7/8.<br>
<br>
One annoyance that I have with a similar task in Ubuntu, and maybe
it's only on my machine, is that logging out of one user will result
in a black blank screen that cannot be released, even with
ctrl+alt+backspace or ctrl+alt+delete. Whenever more than one user
is logged on, we have to leave them on until it's time to shut down.<br>
<br>
The above problem does not seem to occur on my mother-in-law's
machine using Ubuntu, or even in this one when using a different
distro.<br>
<br>
John.<br>
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