[CentOS] Re: Language interfaces and X.Org sessions per user

Sun Sep 16 17:09:09 UTC 2007
Ross S. W. Walker <rwalker at medallion.com>

William L. Maltby wrote:
> On Wed, 2007-09-12 at 17:23 +0300, Ioannis Vranos wrote:
> > OS: CentOS 5.0 x86.
> > 
> > 
> > Q1: Is it possible different users to have different 
> language interfaces
> >      (menus etc) on the same machine under X.Org (GNOME or KDE)?
> I'm not familiar enough with this to help, but I've done 
> something that
> may help you find your way on the next question. I suspect the normal
> LC_* environmental stuff will be needed for the language solution.

Yes, so long as you have all the language packages installed for each
language for each GUI (KDE, Gnome, XFCE, etc).

Console language selection is set through .profile or .login or .bashrc
and setting the LANG= environment variable.

GUI language selection is set through the settings applet of that
particular GUI.

> > 
> > Q2: Is it possible to have more than one X.Org sessions 
> running on the
> >      same machine, so as different users to log in at the 
> same time, and
> >      switch between users X.Org sessions (one using GNOME, 
> other using 
> > XFCE)
> >      by using the usual Ctrl-Alt-Fx keys?
> <soapbox>
> It may be redundant, but please be *aware* of the security 
> implications
> of what you are seeking. "The law of unintended consequences" will
> certainly come into play if you are truly multi-user. Effects 
> in social
> interactions, swap usage, system responsiveness can all be 
> expected. You
> can expect to be asked to do an excessive numbers of restores 
> of backup
> at a specific point in time (which you won't have) as user A destroys
> user B's stuff, by intent or accident.
> </soapbox>

Hogwash, while yes you will definitely need more resources as far
as hard disk, memory and network there is no need to worry about user
X overwritting user Y's data. Hell Unix and it's variants had been
successfully doing multi-user X sessions for years before even Windows
95 was a glint in Bill's eyes.

Please put user home directories on a RAID10 share as things like
Firefox HTML cache cause lots of random IO per-user.

> As root, from shell,
>     startx -- :1  # or 2, 3, ...
> gets a session started as root. There are more params that can be
> passed.
> For a login process, a basic process is
>     xdm -server ":1 local /usr/X11R6/bin/X :1"  # or 2, 3, ...
> This gets a basic default layout session going. Other files and
> parameters may be needed to suit your needs.
> Your friend is "man xdm" and *many* others: startx, X, ... follow the
> path in the "See Also" sections.
> Many of the files are scripts. Viewing them can prove instructive.
> I've not looked (no need) but I bet there are "primers" out on the web
> for this sort of stuff too.
> Investigate also, this line from /etc/inittab. It may prove 
> more useful
> to allow automatic start of the extra X instances.
>     x:5:respawn:/etc/X11/prefdm -nodaemon
> I would have responded sooner, but I'm such a neophyte at this X stuff
> that I felt certain someone else would answer with better information.

Look at /etc/X11/xdm/Xaccess (for vanilla xdm)

If running kdm look at /etc/kde/kdm/kdmrc for extra security settings.

Basically you'll have your X server broadcast it's services for all X
clients to choose to use, you may also need to have your font server
allow connections from X clients so the clients can have access to
the same fonts as the server.

For multiple user sessions on a single workstation I believe both KDE
and Gnome support this (I know KDE does for sure).


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