/[http://wiki.kde.org/tiki-index.php?page=KDE+Community+World+Summit|aKademy] / [http://wiki.kde.org/tiki-index.php?page=Talks+@+aKademy|Talks] / Knoppix Remastering and Free NX Demonstrations

-=Remastering Knoppix and Free NX Demonstrations by Fabian Franz=-

ISO image is booted straight form hard disk using bootfrom= parameter on startup which was added in 3.4.

Knoppix remastering was quite a difficult task.  Lots of commands to import but always the same commands so he has decided to do a script so everyone can remaster Knoppix.  The only thing you need to know is how to use Debian.  Who is familiar with Debian?  Most people put up hands.

We need a free partition so use QtParted to make one.  He downloads the script available from http://debian.tu-bs.de/knoppix/remaster/.   Start script, asks us if we want to create a new remaster (we do).  Asks where to start it (newly created partition).  Copies files which takes a while even from hard disk.  Anyone know dpkg-query?  Not many do.  It can be useful in making removing software easier, you have to remove software when remastering Knoppix otherwise there will not be any room for more software.  dpkg -l will show the packages.  dpkg --get-selections gives you the installed packages.  We want to know the sizes of them which can be done with dpkg-query -W which outputs all pacakges with version number.  dpkg-query -W --showformat='${Installed-Size}\t${Package}\n' | sort -n  shows us the packages in order of size.  Openoffice is largest so if you just remove openoffice you have space for most things.  You can't just remove libc6, that would be bad.

You can remove packages by section, e.g. remove all Debian related packages:


 dpkg-query -W --showformat '${Section}\t${Installed-Size}\t${Package}\n' | sort -n | grep ^devel | awk '{ print $3 }'

His script has now finished copying the Knoppix cloop iso.  It offers several options including the option to try compressing with 7-gzip which can end up smaller but takes longer.  You can also use a sort file which makes the CD be read much faster.  There is a script to fix hardlinks because they don't work normally on the cloop ISO file. (Run /KNOPPIX.build/Knoppix.hardlinks from the chroot.)

debfoster is another great command for removing unnecessary packages.  It knows the dependencies and asks what to remove.  debfoster -n will work on all installed packages not just newly installed ones. Pressing x allows to create a new "keeped packages" file then.

The script uses Klaus's origional remastering scripts, it will not miss out any steps e.g. problems when upgrading ssh starting the service automatically (which is not wanted in most cases).

This scripts may be included in Knoppix in the future but not in any menu, same as the installer script.  Apparantly Knoppix once got an e-mail saying "I formatted my hard drive and installed Linux and it's cool but I want to go back to Windows now, how do I get my data back".  So the installer will stay as a hidden option.

It is possible to use netcat to send the compression to another network and get the compressed data back which is useful if you have a slow computer.  The script can also make a swapfile if necessary.

Final step is to create the actual ISO containing the compressed ISO.  It also makes a checksum, knoppix is able to check it's own data on startup with the correct boot parameter.

Demonstration of NX, logges into his home machine on a 128K upstream ADSL and can use it quite happily with only a little lag which reduced in time because the cache is built up.  All X images are compressed with JPEG compression.  Text is not compressed so it sharp.  This shows the power of the old X protocol, people who say that X should be replaced need to see this.  Over a GSM mobile phone Mozilla takes 7 minutes to start up with ssh -X, using NX machine it starts up in 20 seconds.  He demonstrates suspending an X session, the session can be completely restored like `screen` for X (this is a first for X).  NX is more advanced than VNC which just takes screenshots and transfers the images, this transfers X protocol items.  Unlike VNC this needs only one login, VNC has its own login.

At the NX BoF meeting it was decided a more friendly name needs to be found.  They want to integrate it into KDE e.g. in the remote desktop application.  Kurt desribed doing an NX demonstration with Keith Packard and Jim Gettys and others where they did not believe it could live up to its claims.  Kurt ssh'd into a machine and ran `ls -rl /` on the command line.  Then connected via NX, started up Konsole remotely and ran `ls -rl /`.  The NX system was 3 times faster than running it remotely on the command line.

They want to integrate this into KDE.