Mixing 8 and 16/24/32 bit displays in Linux (Redhat)

Problem

Older display software, such as WEB, does not support displays higher than 8-bit
Usually people use 24 or 32 bit "truecolour" displays, since 8-bit is limited to 255 colours
This solution allows normal use of 24/32 bit display, plus an extra 8-bit display
When running, press CTRL-ALT-F8 to switch to 8- bit display. Press CTRL-ALT-F7 to go back to normal display

Assumptions

Tested in Redhat Linux 7,8,9 and Fedore Core 3
Probably will work in other distribtions as well
Will work in KDE or GNOME
uses a "minimal" window manager, either twm or icewm, for the 8-bit display

Setting up

Edit the file /etc/X11/XF86Config (Redhat 7-9) or /etc/X11/xorg.conf (Fedore Core) as follows:
Find the "Screen" section, and duplicate the 24-bit depth Subsection, changing 24-bit to 8-bit. Example:

Section "Screen"
        Identifier   "Screen0"
        Device       "ATI Mach64"
        Monitor      "Monitor0"
        DefaultDepth    24

        Subsection "Display"
                Depth       24
                Modes       "1280x1024" "1280x960" "1152x864" "1024x768" "800x600" "640x480"
        EndSubsection

        Subsection "Display"
                Depth       8
                Modes       "1280x1024" "1280x960" "1152x864" "1024x768" "800x600" "640x480"
        EndSubsection

EndSection

Edit /etc/X11/xdm/Xservers to add a new screen, and tell it where to put the screens. It should look like this when done:

# $Xorg: Xserv.ws.cpp,v 1.3 2000/08/17 19:54:17 cpqbld Exp $
#
# Xservers file, workstation prototype
#
# This file should contain an entry to start the server on the
# local display; if you have more than one display (not screen),
# you can add entries to the list (one per line).  If you also
# have some X terminals connected which do not support XDMCP,
# you can add them here as well.  Each X terminal line should
# look like:
#       XTerminalName:0 foreign
#
:0 local /usr/X11R6/bin/X vt7
:1 local /usr/X11R6/bin/X -depth 8 vt8

Optional : Install icewm using yum
yum install icewm
Place the file "startx8.com" in your home directory.

startx8.com

#!/bin/csh

if (-e $home/.Xclients) mv $home/.Xclients $home/.Xclients-orig

# starts an 8-bit display in window 2 using fluxbox
#echo exec /usr/local/bin/fluxbox > $home/.Xclients

# start an xwindow display using twm (installed with redhat)
echo exec /usr/X11R6/bin/twm > $home/.Xclients

# start an xwindow display using icewm
#echo exec /usr/bin/icewm > $home/.Xclients

chmod a+x $home/.Xclients
startx -- :1 -depth 8

rm  -f $home/.Xclients
if (-e $home/.Xclients-orig) mv $home/.Xclients-orig $home/.Xclients

Uncomment the appropriate command (twm, icewm or fluxbox) depending on the window manager installed. twm is already installed by Redhat.
Make the file executable:

chmod a+x ~/startx8.com

Running the program

After you already have your normal X-display started, press CTRL-ALT-F2 to go to a new text login window
Log in, then run the command

./startx8.com

A new X-window should start up.
To switch back to your old window, press CTRL-ALT-F7. This one is accessed by CTRL-ALT-F8

twm instructions

twm is a VERY MINIMAL X display
To run a program, hold down left-click -- a menu will pop up
Select xterm to run an x-terminal
When new windows open, they open as hollow boxes. Move the box where you want the window, then click
To resize the window, click and hold the box in the upper right corner
To close a window (twm does not have a close button) , click the desktop until the menu comes up, then select kill
- Move the skull and crossbones cursor over the window, click and it will be closed
Better to install IceWM and use that

Problems running web in recent Redhat (Fedora core 8)

FC8 does not contain the correct libraries to run web -- it needs libXm.so.3, part of openmotif
Download the proper openmotif2.3.0 rpm from http://www.motifzone.net/index.php
It has a dependency: libXP.so.6
- The rpm for this can be found at
  http://rpmfind.net/linux/rpm2html/search.php?query=libXp.so.6

install both rpms: in FC8,

   rpm -ivh libXp-1.0.0-8.fc8.i386.rpm openmotif-2.3.0-1.fc8.i386.rpm

Be sure to set LD_LIBRARY_PATH variable to include /usr/X11R6/lib
Also, web needs an older version of openmotif, but can make a soft link to the version web wants:

sudo ln -s /usr/X11R6/lib/libXm.so.4.0.0 /usr/X11R6/lib/libXm.so.3

A second way to get an 8-bit display

from instructions on Wadsworth site
Use vnc (Virtual Network Computing) to create a virtual display.
Most GNU/Linux distributions include vnc in their default installation which can be used to create a virtual display in a window on your current desktop.
If it is not installed, try

      > yum install vnc vnc-server

When vnc is installed:

       > vncserver -cc 3 -depth 8

Provide a password

To run the display:

        vncviewer :1

Provide the same password

Opens new desktop within a window
Here you can start web_linux normally or you can start it automatically by editing your vnc viewer startup file: ~/.vnc/xstartup

        
vncserver -kill :1

Kills the vnc server.

Can also simply close the window. When you reopen, you will be in the same place

-- BillRice - 22 Aug 2006