Nice way to describe Kerberos: a Dialogue in Four Scenes

As I needed to refresh my knowledge about Kerberos, I found a nice theater-like Dialogue in Four Scenes. Kerberos is really complex and hard to follow. It is revealing that its authors found theater more efficient than traditional technical docs and schema to explain their ideas.
It remember me of the comics used by Google to describe Chrome. Only it was done in 1988 !!
Also the best theater reference for me is always Ralph König's Lysistrata, his prologue really strikes me.

MDSD: UML or DSL ?

This blog is a lot about Linux, because I use it as a reminder. I want to remember how I solved some problems or some great applications or short cut.
But it doesn't reflect my main interest that is development, design and creation. My Google Reader Shared post gives a better view of this part.
Also how I shifted my interest from Semantic web to Model Driven Development and DSL.
So I will just notice that I didn't realize how UML and DSL can be antagonist.

Sound and iPod with Awesome Windows Manager

Just a short note about the great Awesome window manager.
There was no sound with some applications. There are 2 programs to know about sound control : alsamixer (command line) and pavucontrol (manage PulseAudio with a simple GTK interface).

For the iPod, I am using RockBox, gtkPod and gpodder. Nothing fancy, but it does the job quickly.

Just have to remember to manually mount the iPod, by adding this in /etc/fstab:
/dev/disk/by-label/IPOD /media/IPOD vfat defaults,umask=000,auto,rw,user 0 0

Also a simple trick to eject the iPod : eject /media/IPOD

LUA, commun point for VLC, Awesome, SciTE ...

It is amazing to see that most of the software I like and use embed LUA, the "powerful, fast, lightweight, embeddable scripting language" :

• VLC Multimedia player can uses LUA playlist.
• Awesome Window Manager can be extended with LUA:
• SciTE source code editor can be extended with LUA.
• Rockbox firmware for mp3 players can be configured with LUA too, even if I cannot find a good official link.
• Grub 2 the boot manager has integrated lua as an alternative script engine.

It is good to know that you can invest into it.

Getting rid of the DisplayManager, Choose your run level

The Display Manager (generally: GDM, KDM, or XDM, Slim ...) is there for historical reason, but it isn't useful unless you need special features.
Now the problem is that Ubuntu restricted the uses of Run Levels ! So you have to tweak the system a little bit if you want to start in text mode.
So lets read:
Add a text-only runlevel to Ubuntu Gutsy and
Boot time RunLevel
Then modify your /etc/event.d/rc-default:

#
# This task guesses what the "default runlevel" should be and starts the
# appropriate script.

start on stopped rcS

script
      runlevel --reboot || true

      if grep -q -w -- "-s\|single\|S" /proc/cmdline; then
          telinit S
      elif RL="$(grep -o "[[:blank:]][2345]$" /proc/cmdline || true)"; then
          if [ -n "$RL" ]; then
              telinit $RL
          else
              telinit 2
          fi
      elif [ -r /etc/inittab ]; then
          RL="$(sed -n -e "/^id:[0-9]*:initdefault:/{s/^id://;s/:.*//;p}" /etc/inittab || true)"
          if [ -n "$RL" ]; then
              telinit $RL
          else
              telinit 2
          fi
      else
          telinit 2
      fi
end script

Then knowing that I use Grub 2, the following file has to be modified /etc/grub.d/10_linux (no more menu.lst). Just add the bold part:

...
 cat << EOF
menuentry "${OS}, linux ${version}" {
       linux   ${rel_dirname}/${basename} root=${linux_root_device_thisversion} ro ${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT}
EOF
 if test -n "${initrd}" ; then
   cat << EOF
       initrd  ${rel_dirname}/${initrd}
EOF
 fi
 cat << EOF
}
EOF

 cat << EOF
menuentry "${OS}, linux ${version} (text mode)" {
       linux   ${rel_dirname}/${basename} root=${linux_root_device_thisversion} ro 3 ${GRUB_CMDLINE_LINUX}
EOF
 if test -n "${initrd}" ; then
   cat << EOF
       initrd  ${rel_dirname}/${initrd}
EOF
 fi
 cat << EOF
}
EOF

 cat << EOF
menuentry "${OS}, linux ${version} (single-user mode)" {
       linux   ${rel_dirname}/${basename} root=${linux_root_device_thisversion} ro single ${GRUB_CMDLINE_LINUX}
EOF
 if test -n "${initrd}" ; then
   cat << EOF
       initrd  ${rel_dirname}/${initrd}
EOF
 fi
 cat << EOF
}
EOF

...

That worked for me, but be careful as it can screw your system !
Now just log in and type: $ startx awesome

Set up wireless without KDE nor Gnome

One of the first problem faced when going away from KDE, Gnome or XFCE is that you have to set up your wireless connection manually.
If you have 10 minutes, it can be done once and for all: just follow this how to HOWTO: Wireless Security - WPA1, WPA2, LEAP, etc..
Then you can remove the NetworkManager startup script : "sudo update-rc.d -f NetworkManager remove".
Keep in mind to launch a "sudo /etc/init.d/networking restart" in case of problem.

Update: I just found a solution to automatically start Network Monitor Applet (nm-applet) with Awesome Window Manager. But I am quite happy with my current setting, it just connect when it starts.

Java GUI application in Awesome Window Manager

There is a known problem with Java and the non-reparenting Window Managers like for example Awesome.

Java applications which use the XToolkit/XAWT backend may draw gray windows only. The XToolkit/XAWT backend breaks ICCCM-compliance in JDK 5 and 6 because it assumes a reparenting window manager.

There are a number of places where this is described:

• in the FAQ : GUI Java apps appear as a gray screen!


• in the wiki Problems with Java


• in the Man page

To sum up:

• it doesn't affect version Java 1.4.2 and before.


• it doesn't affect version Java 1.7 and hopefully after.


• the best workaround by far, is to set a name to the Window Manager, so it is recognise by Java as a non-reparenting Window Manager. A simple utility allow to set this name. Just add 'wmname LG3D' to your .xinitrc or simply run it.


• Here are other workarounds left here for reference:


• launch another X server, like Xephyr


• set the following environment variable (to use the older Motif back-end instead): AWT_TOOLKIT=MToolkit. But this won't work in the following cases :
  
  • OpenJDK/IcedTea doesn't include the Motif toolkit.
  
  
  • doesn't work for x86_64 Java, for whatever reason.