luges (Linux User Group Esslingen)

Yesterday (2010-02-06) Benjamin and myself were again in Lech/Zürs snowboarding; just like three weeks ago. Last time (2010-01-17) Pattrick and Torsten were also able to join. This time it was only Benjamin and me.

The weather was similar to our last visit. Mostly cloudy with a few peeks of sunshine. This time, however, we had lots of new deep powder and it was freeriding time. Extremely exhausting but great fun.

Me and my colleague are responsible for linux installations at our customer. In our scenario installations are complicated:

• We are not allowed to operate an own DHCP server. The corporate DHCP server does not allow us to modify the TFTP/NFS Server settings
• Our users/clients are not at our site which makes installations difficult: We have to go to our users or our users have to bring-in their client. The distance to our customers is high
• Users with different hardware (RAM, HD,…) and different configuration (local users,…)

Finally we found a solution which allows us to do installations with FAI. FAI is a tool for mass unattended Linux installation. FAI works well when your hardware and configuration is the same. As we have different clients we had to implement a hook for interactive configuration.
The picture shows our final installation procedure:

We prepared an ISO file to allow our customers to remote boot an rescue system with SSH enabled. This ISO file does not have to be touched anymore as all configuration is stored on our servers. The user would only have to write this ISO (a dd-dump) to an USB stick, connect it with the client to be installed and power it on. The rescue system gets an IP with DHCP and uses a NFS export of our server as nfsroot. The kernel parameter nfsroot= make sure it uses our NFS server. After booting the rescue system, the User gets a message with the actual IP and our telephone number. The user has to call us to start the installation procedure.

We can then connect with ssh and the client IP. As the nfsroot contains our public SSH keys we do not need any passwords. Our corporate DNS allows the use of dynamic DNS. It would also be possible to use a hostname to connect. Unfortunatelly the actual “ipconfig” in the ramdisk has not all DHCP features included and does not send its own hostname in the DHCPREQUEST. There exists already a patch, but it is still not merged.
Before this “rescue linux with nfsroot=” solution we tried gPXE and a patch of me. It did do the DNS update, but gPXE has problems booting some NICs so we abandoned it.

After log-in with ssh we start with preconfiguration of some individual items which would not make sense to configure them in our FAI repository: userid of the owner, install target (sda/sdb/….), encryption yes/no, size of the swappartition,…
The config is written to /tmp/fai/myvars.sh. Hooks and scripts can later access this config to prevent user interaction during installation.
We trigger then the start of the installation procedure (FAI) and watch the installation progress with

tail -f /tmp/fai/fai.log

FAI uses tarballs as base image and installs further packages on it. To speed up the installation we have images with preinstalled KDE/GNOME.

Now we have a standard way to install our clients. FAI also allows to install other distributions like Ubuntu, but it is still not the same : Installations with DVD are different with FAI.
FAI requires a list of packages to be installed. It would be helpful if Ubuntu would provide a meta-package which would also install the same packages as the Ubuntu installer does. FAI could then do the same procedure without using a tarball.

My employer has a big active directory infrastructure with many subsidaries. While configuring Linuxnotebooks to authenticate with kerberos (pam_krb5) against Active Directory. I was asking myself why I have to insert all our local corporate Active Directory server IPs into krb5.conf. Is there no way to just use the DNS-Name of the Domain-Name to locate my nearest Domain Controller? How do Windows XP Clients locate a domain controller? I asked a similar question already 7 years ago, but now I am able to answer this question. The KB Article of MS did not satisfy me so I tried to put here together the most interessting information.

Here is a strong simplification how a XP Client discovers a Domain Controller:

• Step 1) Lookup SRV-/A-Records for a given Domainname to locate a random Domain Controller.
  

  $ DOMAIN=mydomain.example.net
  $ dig -t srv _ldap._tcp.$DOMAIN +short

• Step 2) The Records of some Domain Controller are returned. We could use this results to log-in and stop here, but the client tries to discover an DC near its site.
• Step 3) In the order of the results the Domain Controller are contacted with an “LDAP Ping”. This is an connection-less and anonymous LDAPSEARCH over UDP. In the Samba source is a script 
which allows sending cldap datagrams to a DC LINK
  

  ./cldap.pl –domain $DOMAIN –server

• Step 4) Active Directory has a map between “sites” and “subnets”. The Domain Controller compares the client IP with its map and returns the name of the “site” (here: SiteA)
• Step 5) The Client will use the “site” in further DNS request to locate Domain Controllers at its site.
  

  $ dig -t srv _ldap._tcp.SiteA._sites._msdcs.$DOMAIN +short

• Step 6) The DNS responds with Domain Controllers responsible for SiteA
• Step 7+8) The client uses the Domain Controllers in its site in further requests. The client saves the sitename in a registry key DynamicSiteName to prevent step 1)-6). The client could also be forced to use a certain site with setting the registry key SiteName. Beginning with Windows Vista, it is also possible for a client to lookup the nearest DC with the associated costs.

Why do I explain explain this stuff on a LinuxBlog? Because I would be happy to see these features more in linux applications (e.g. ldapsearch).

site-discovery
If there a different locations with site-local servers, the client should alway use its nearest server to prevent WAN traffic.
This technique is also used in CDNs. There are also some approaches with geoip and DNS which could be helpful here. Some years ago I had to modify all site-local DNS servers so that the same DNS entry returns the IP of our site-local OpenVPN server but this was more a hack than a technique.

single DNS entry = all available servers
Instead of configuring different servers in client applications e.g. ldap1,ldap2,ldap3,…. it would be nicer (?) to control the clients just with one DNS entry.
This would also make the applications more robust as new failover servers can easily be published via DNS.
If the first IP returned by DNS is unavailable, the client should also use the other results (just like SMTP does it with MX-records)
Using DNS instead of an IP is also not a drawback her as there are usually more than one working DNS server in an organisation. As DNS is replicated, the same information is available on all other DNS servers, too.

btw: A microsoft consultant told me, that samba is site-aware – Nice!
Update: Also Yum supports site-discovery and fault-tolerance

This month's come together will be held on 2010-02-03, 8pm at our regular pub (Trödler).

Agenda: http://lisas.de/pipermail/luges/2010-February/005278.html

My Touran reached the 100000 km “milestone” today:

At my current project I came across Java Server Faces (JSF) for implementing the user interfaces for a Java JEE application. I read some great online tutorials (e.g. The BalusC Code) for preparation and Java Server Faces – the Complete Reference by Chris Schalk and Ed Burns (paperback, no eBook) for self-studying and must say: I really like JSF. The learning curve is a bit steep, but once you got it, it’s so much fun.

Especially when you enhance your environment with additional libraries like Apache Tomahawk. Nice UI enhancements like tabbed panes and trees.

Only thing: I’m not sure if I implement the backing beans the right way. Currently I implement them as wrappers for our model driven design. We have a data model in XSD. I use JAXB to generate the corresponding Java classes and the backing bean for mapping them to Strings, ArrayLists etc. in the UI, because the model is rather complex and I don’t need the complexity within my backing beans but still need to access the complete data model. I don’t want to hold the data twice in memory.

To populate the data objects I need EJB3 and WebService interfaces. Very time consuming, but it’s the only way to access external systems.

Let’s see how it scales when we start load testing…

For rapid development I use Eclipse and Glassfish, Plugins like EclEmma, Jad (JadClipse), Glassfish Connector and their equivalents on the command line within a self-made ANT-based build environment (you need to be IDE independent, aren’t you? ^^), which also does JUnit tests and reporting (JavaDoc, JUnit test results, code coverage report, assembling documentation files) besides building the deployment deliverable.

It’s not all that hard to develop within this environment for different target application servers, like e.g. WebSphere.

Another nice feature is remote debugging, which can be easily done from Eclipse using the Java remote debugging protocol. Good debugging tools are such a time-saver! Well, object inspection could be a bit better in Eclipse, but there are enhancement tools like POI from programmer’s friend.

It takes some time to set this all up (and managers don’t see that effort) – but now I’m really happy with my development setup. Years of work. ^^ And this setup can be applied to different projects (EJB, WebServices, plain old Java, …) as a template.

Just type “ant”.

My desktop had a hardware problem with the motherboard. I decided to upgrade several components and am currently writing on a smooth new desktop system. I also upgraded the GPU because this has been the bottleneck of my system.

The new components are:

Board: ASUS P7P55D P55
CPU: Intel Core i5 750 4×2.66GHz
GPU: NVidia Palit (R) GTX260 Sonic Core216 55nm HDM
RAM: 4096MB Corsair XMS3 PC3-1600 CL8

Now the harddrive is the bottleneck.

For a few days now I get strange sudden reboots running Windows 7 on my desktop PC. In the Windows event log it says it’s a critical power failure (event ID 41, task category 63). I also noticed sudden shutdowns when shutting down Linux – no sudden reboots, but the system shut down instantly resulting in a fsck after booting. Problem is: it’s not repeatable.

It all started when I recovered some files from a hard drive of my brother in law for which I had to disconnect one of the internal hard drives. I checked all the cables over and over again, upgraded most of my hardware drivers and did a memory check with Memtest. Nothing. I also checked the power of the PSU via software (SpeedFan) – all within the limits, as well as the temperatures of the CPU and GPU.

Today I changed the PSU and installed a BeQuiet! Straight Power 600W E7. 600 watts seem a bit oversized, but test results for this PSU have been very promising for stability and energy consumption/saving. I hope it really was the PSU and not the motherboard and/or CPU. Otherwise I have to buy replacements (and upgrade to a quadcore processor – which wouldn’t be _that_ tragic ^^).

This weekend the table tennis city championships take place in Kirchheim. Over 400 players will participate in various competitions – the tournament is one of the biggest in the whole district.

I don’t expect to win anything, but I hope to perform at least as well as last year. The club championships however have been a success for me, we won the 3rd/4th place in the double competition by reaching the semi-finals – losing against the later champions team.

Club championships certificate and award cup

… and I got elected “player of the year” – w00t!

Tomorrow we will start the final preparations for the tournament – cleaning the tables, fixing the nets. Friday night we will prepare everything in the gymnasium (tables, lunch room, cafeteria, …) and Saturday and Sunday will start at 7:30 am for the tournament administration team which I’m part of.

Gymnasium LUG at a normal league play day

The service will end at around 10:00 pm. But I’m really looking forward to it because it’s a great event with lots of fantastic players (players of the 2nd German national league will participate, former national team players of different countries, our own club’s participants of European and world championships) and it’s gonna be a lot of fun with my teammates.

Since yesterday I had trouble getting into ICQ with the Pidgin IM client: “Received unexpected response from http://api.oscar.aol.com/aim/startOSCARSession”. Most of my friends use Jabber now, but there are still some left with ICQ accounts. To fix it I had to remove the “use clientLogin” property in the advanced tab of the account settings pane.

This month's come together will be held on 2010-01-13, 8pm at our regular pub (Trödler).

Since Monday I am at the High Performance Computing Center Stuttgart (HLRS) and I have started the initial installation of our cluster.The people from the HLRS have offered to support us with the initial installation, which we gladly accepted because they know how to do clusters.

On Monday I installed the three infrastructure servers which are used to control the 180 nodes of the cluster. The cluster is running Scientific Linux and my first task was to get it on those three infrastructure servers.

Those servers have two 500GB disks and they were supposed to be running as software RAID. After the seventh failed attempt to configure the partitions as RAID1 with the Scientific Linux installer we used a Debian install DVD to partition the disks and after the successful configuration of the partitions as RAID1 we installed Scientific Linux on all three systems. Not knowing how to use anaconda to configure a RAID1 (like we wanted to) was a bit embarrassing, but with all the Fedora and CentOS installation I have done I have never configured a software RAID1 from the installer; either the system had only one disk, a hardware RAID controller or I configured the RAID manually after the installation. But at the end of the day all three system were installed and configured for their tasks.

Today (Tuesday) we used the installation to boot the first two nodes of the cluster. All the nodes are running disk-less and are booting over TFTP/NFS from a single read-only image.

Last week I have finally updated our mirror server to Fedora 12. It was still running Fedora 10 which has reached its end of life. The server was running Fedora 10 for a long time and it was always running with a CentOS kernel. The Fedora kernels were, at the beginning, not stable enough (crashing after three or four days) so that I quickly switched to a CentOS kernel. I know that I should have reported bugs, but in the case of the mirror server I am more concerned to keep it up and running than getting debug data from it. It also not easy for me to get physically to the machine so that I had a lot of good excuses to switch to a CentOS kernel.

Now the system is running using the Fedora 12 kernel and after a week it is still up without any problems.

I am running one of the RPM Fusion builders in a VM using CentOS and after I saw that the newly created VMs on my notebook are using virtio for network and disk access I thought that I will try this also for my builder VM. It was pretty easy and straight forward.

First I had to update from CentOS 5.2 to CentOS 5.4 so that the virtio drivers are available. After that I was just following http://wiki.libvirt.org/page/Virtio.

For the network:

• shut down the VM
• edit the XML and add <model type='virtio'/> to the network section
• start the VM
• done

For the disk:

• create a new ramdisk with the virtio drivers: mkinitrd --with virtio_pci --with virtio_blk -f /boot/initrd-$(uname -r).img $(uname -r)
• or dracut -f --add-drivers "virtio_pci virtio_blk" /boot/initrd-$(uname -r).img $(uname -r) for Fedora 12
• change /boot/grub/device.map from “(hd0) /dev/hda” to “(hd0) /dev/vda“
• using LVM requires no changes to the root= parameter in /etc/grub.conf
• shut down the VM
• edit the XML changing <target dev='hda' bus='ide'/> to <target dev='vda' bus='virtio'/>
• start the VM
• done

During the boot of the VM I can now see that it is loading the virtio disk drivers and detecting vda1 and vda2. Using lspci and lsmod I can also verify that the new virtio devices are available and also used. The VM seems to be faster but I have not actually benchmarked it.

On the last day of the last year (2009-12-31) both RPM Fusion’s mirrorlist server were most of the time not reachable. The problem started at 00:53 (UTC) and it was at least going on until 16:00 (UTC). Both mirrorlist servers have been on the same network and the router for that network  broke down. If it would have been the link to our provider the router had a backup route to stay on-line, but this time it actually hit the single point of failure – and everything was off-line. See: error report of the provider (german).

I was never happy that both mirrorlist server were running in the same network and I especially wanted to get the mirrorlist server off my mirror server. Thanks to Patrick I have now access to another VM at a different provider where I am running a new mirrorlist server instance. It does not require much in terms of resources and bandwidth, but having root access makes everything so much easier.

RPM Fusion’s mirrorlist server are now two dedicated VMs at two different providers and that should protect the functionality from failures like the one on 2009-12-31.

I had already user experience with Kerberos, but now I wanted to install it myself. I took the MIT Kerberos implentation. Even I was used to use “single-sign-on” with SSH keys, it was amazing to see how ssh, telnet, smbclient and ldapsearch on an Active Directory Server works without logging in. Kerberos is also capable to encrypt telnet network traffic.
Installation was fast, too. It took only long to understand the architecture of Kerberos. Fortunatelly oreilly has a nice book, too.

I read a whole book about OpenLDAP to use all features of a directory server. I managed to migrate from flat files to LDAP and set-up replication. Samba is using OpenLDAP as backend, too. Installation was really fast and it was quite uncomplicated.

Together with some colleagues we rented a rootserver at Hetzner. Everyone has now an own KVM guest with 512 MB RAM and 50 GB HD. Usually KVM uses a bridged network setup when using official IPs. As Hetzner routes the IP to the rootserver (instead of switching it), we had to built a small virtualised routed network with internal transfer IPs so supply the guest with network connection.
On demand from Adrian I spent a KVM guest as mirrorlist-server for rpmfusion.

Adrian just upgraded lisas.de to Fedora 12 and that brought us an upgraded python. Unfortunately the current planet version uses the md5 module which has now been deprecated, so cron now sends me one deprecation warning per hour, which is rather frustrating. I wrote a little patch to fix the planet and this entry will be the one to test the patched planet with. If it works I’ll add the patch to bug #552462.

I’ve moved my printer to another room. Now it’s connected to my continuously running computer. But it’s constantly connected to power and is not really switching off. So I was searching for a solution to switch it of automatically. Using a µC would be nice, but the idea a the moment is to use a USB->serial converter and us the status pin RTS to switch a solid state relay. Today I’ve successfully tested the setup. First I tried with python, which in general is able to set the status of that pin, but unfortunately python is too “high”. During initialization and termination RTS is touched. And I don’t want to “shock” my printer with short switching pulses. But I’ve found this C-code. This allows to keep the state of the pin after termination of the program. This little piece of code exactly does what I need. I’ve added a diode before connecting RTS to the solid state relay to make sure that the relay does not see a negative voltage. I can not yet post a picture of that because my prototype is highly dangerous and I don’t want to provide any examples of dangerous 230V wiring on the net.

The next step will be to set up a cups backend that switches on and off the relay.

Since I’m on holiday I have more time to play with the µC. I’ve now got a 2X16 character display running and I can read temperature from the small one-wire sensors. So I’ve put that together and created a thermometer.

The sensors are the small barely visible black dots on the upper part of the breadboard. The oscilloscope visible on the left I’ve taken with me from office during Christmas holiday since I can’t afford such a thing.

After mirroring ftp.mozilla.org since 2000 we are now finally included in the automatic redirector pool. Chances are, if you are downloading something from mozilla.org, that you will be redirected to our mirror.

So this is the obligatory blogged-on-the-N900 blog entry, straight from the maemo browser running all that WordPress JavaScript. So far, I am pretty amazed, although it’s only one day and I didn’t have much time to play with it. Software and UI are much more polished than I would have expected, and browsing the web works so much better than with any other mobile browser I’ve used so far.

In the night from Friday to Saturday a disk (slot 7) from our external RAID, containing most of the mirror server data, failed and was marked as BAD. No really a big problem, yet. The hot spare drive was activated and the rebuild started. About 24 hours later the rebuild finished. On Sunday (around 16:00) another drive (slot 5) failed and we immediately started to sync all the data to another box in case another drive decides to go off-line, which would mean a complete data loss. All the data on that RAID are (only) mirrored, but to re-sync all the 9TB we currently have would probably take a few weeks. Unfortunately the sync to another box will also take a few days until it is finished, so it is still possible that we might lose a lot. We are waiting for the replacement disks which have been promised to be here by Monday (today), but as the rebuild needs over 24 hours there is still the chance of a data loss.

Update (2009-12-14 23:20): The replacement disks have arrived and after more than twelve hours 25% of the array has been rebuilt.

Update (2009-12-15 11:00): After more than 24 hours 58% of the array has been rebuilt. It seems to rebuild faster during the night.

It’s on its way! I have finally ordered one of these fine mini laptops that can serve as cell phones, too. Now I’m sure that Adrian will taunt me for buying a device that comes with my favorite audio daemon pre-installed, but hey if it works as it should I’m OK with that. What convinced me to get one of these phones is that I will be able to install Debian packages, that it features an XTerm hotkey that will open a shell from anywhere and that it should be useful without relying on my Google account.

Today I picked up my first package from a Packstation. A Packstation allows receiving packages 24/7 without beeing at home. It is quite simple: When a package arrives, a Mail/SMS notifies the receiver. The receiver then needs to go to a Packstation, enter a PIN, open a slot and take the package.

The Wifi reception with my Fritz!Box is quite well through the whole house, but not well enough to watch digitalized movies on the laptop from my NAS in the winter garden. So I was looking for a WLAN repeater. While browsing through various products I quickly decided to buy a Fritz WLAN repeater because of one very cool feature: It can be used as an audio device, too! Either you connect the repeater via cable to your stereo or you can use the built-in FM/UKW mini sender.

Another nice feature is the touchscreen display. You can either display the signal strength, IP address, current time, amount of connected devices etc. pp. on it or free text as a ticker.

So now I can not only decide what music people in the living room have to listen to from my basement, errr, control center, I can also send ticker messages to them. ^^

Not really back in school, but it has been now more than one week that I started my new job at my old university in Esslingen at the beginning of December 2009. After only 11 months at my previous workplace (Matrix Vision) I am now working for the faculty of Information Technology.

I will be responsible for the setup and installation of the new cluster of the university. The cluster will be part of the bwGRiD and it will have around 1500 cores and is currently being installed. It is partly water-cooled and a few days ago the racks were delivered and installed. The cluster is from NEC and we are expecting the servers to be delivered in the next few days. The cluster will be running Scientific Linux.

I am now in the same building as my mirror server. This might be a good thing, because now I am much closer to the hardware and can act faster if something unexpected happens… It might also be a bad thing, because now I am much closer and can experiment with things I would not do if I was not in the same building.

I’ve been to Tours in France. For picking up my sister at the Euro Gusto. This is an exposition comparable to the Slow Food. OK, I’ve to admit it’s not very reasonable to drive 1800 km in 3 days just for having a look at some wine and tasting some smelling cheese. But I like France and it was definitely good to away from work for some days and I had the possibility to correct some of my prejudice about French people. They tried hard to understand my bad French and did not ask for every word I’ve pronounced in a wrong way and they even tried to talk German to me.

The picture shows the things I’ve bought there: cheese, calvados, almonds, fleur de sel and nougat.

The two new hard drives in my NAS are configured as RAID-1 now since the hard drive failure incident. Making backups on two single drives was a bad idea, the hard drive which failed had all my MP3s from digitalized CDs on it. “Real” data was backed up from the NAS to an external drive and with the MP3s I thought I always have the CDs here, so I can digitalize them again. But that takes a lot of time so I thought I give the hard drive another shot and try to mount it in my desktop.

The NAS didn’t recognize it any more but in the desktop it was possible to retrieve most of the MP3s. It’s still making strange noises and I couldn’t restore all of the data, but at least most of it.

To sum it up: If you don’t have a (working!) backup of your data it isn’t important.

One interessting change in Grub2: “The first partition of the disk is now accessed with hd0,1 and not longer with hd0,0″
A german article about further changes in Grub2: linux-magazin.de

This month's come together will be held on 2009-12-02, 8pm at our regular pub (Trödler).

Agenda: http://lisas.de/pipermail/luges/2009-December/005272.html

Ever tried to install the Apache web server with mod_php and mod_perl, MySQL and phpMyAdmin from scratch on a Windows system? It can be quite a PITA to configure all these software components to work well together. XAMPP is a nice distribution with which you have a working development environment in no time.

It’s available for Linux, Windows, Mac OS X and Solaris. On a Linux system I wouldn’t use it, because the Linux distribution takes care of all the dependencies and I never had a problem setting up a LAMP configuration on Fedora, Debian, SuSE or Ubuntu. But for a Windows system this is a really nice thing.

Amazon released an update for the Kindle 2 today which enables native PDF support on the eBook reader now. Great! Only drawback is the lack of a zoom function which makes DIN A4 PDFs hard to read because of the tiny letters. You can however switch the display mode to landscape and read the PDFs in bigger fonts, but the Kindle isn’t really designed for reading in landscape view.

The firmware upgrade went well, no problems, all my eBooks were still there (as expected). Now I can copy PDF eBooks which are in eBook layout directly to the Kindle without converting them before.

Now that the prototype is running it’s time to move on to “series” production. The files of the first version are here.
So a PCB has to be designed and the parts have to be selected and tested. Selecting the parts is not that difficult, but designing a PCB is not that easy since I don’t have any experience. In addition it looks like the old days are finally over. It’s becoming more and more difficult to get non-SMD-parts.
Btw: I’ve updated the pictures. The red background was a little bit too much and had to be changed to black.
Question: Does anybody have a good idea how to take picture to show that the dimming is working?

Today the two hard disks have been delivered. I wasn’t 100% sure if they were supported by the NAS, because the online documentation at D-Link is a little bit outdated. But I can confirm now that Western Digital WD15EADS Caviar Green 1.5TB hard drives are running nicely within the D-Link DNS-323.

Last weekend one of my NAS hard drives started to make strange noices: “click… click… click…”. Good thing I have a backup strategy which syncs the NAS with another external storage at a remote place.

When I was looking for a replacement 400 GB hard drive online I realized how much the hard drive prices have dropped and ordered two 1.5 TB S-ATA II drives which I will configure to operate as RAID-1 in the NAS. I also took the opportunity to upgrade to a new firmware version (1.07) which offers some new features – most importantly the support of 1.5 TB hard drives.

Didn’t know that until today. We had some issues with UnsupportedClassVersionErrors today at work. So I checked some class files for the Java SDK they had been compiled with. In order to identify the version you can check the .class files in a hexeditor like hexedit and map the minor (bytes 5+6) and major (bytes 7+8) number with this table to the SDK version:

major	minor	Java platform version
45	3	1.0
45	3	1.1
46	0	1.2
47	0	1.3
48	0	1.4
49	0	1.5
50	0	1.6

Java .class files start with a magic number (first 4 bytes) in order to identify them as Java files, 32hex in byte 8 meens 50 in decimal, so the SDK the .class file has been compiled with was Java SDK 1.6/6.0.


00000000 CA FE BA BE 00 00 00 32 00 0F 0A 00 03 00 0C 07 .......2........
00000010 00 0D 07 00 0E 01 00 06 3C 69 6E 69 74 3E 01 00 ..........


In Java’s case the magic number is “Café babe” in hex letters (A-F). More hexfun magic numbers can be found in this Wikipedia article.

I’m currently writing a little PHP/MySQL website which allows players to registrate to our club’s championships. This will be a prototype for the website for the city championships in January.

Because it’s not desirable to install phpMyAdmin on the webserver I will use a nice package from PEAR called Spreadsheet_Excel_Writer which allows to export MySQL database content into Excel format in a convenient way.

We are now part of the rsync.de.gentoo.org and rsync.europe.gentoo.org rotation.

We went to a barbecue seminar in Stuttgart/Feuerbach this Saturday. The theme of the seminar was “Christmas”, so the menu has been:

• duck breast on orange sauce and field salad
• saint pete’s fish with vegetables, spring onion and walnut
• rolled rib of beef with red cabbage
• and a baked apple for dessert

The trainers have been BBQ champions in Germany for a couple of times and the grills we used have been really great (and expensive). We also got certificates after the seminar:

We got a lot of useful tips and it has been great fun, too. But I won’t buy a new grill (yet), because I’m still very happy with my “Adelaide”. Maybe I should have bought a model with a top cover. On the other hand: we already have a kitchen and an oven. These guys cook literally everything on the grill.

While idling in front of my desktop watching the karmic update complete, I decided it was time for a fresh wall paper. So I put some of the good, old convergence onto a photo I took at our local tram museum recently. In case you want to run underneath a historic tramway, too, here a three different resolution edits (1280×1024, 1680×1050 and 2560×1024):

This month's come together will be held on 2009-11-04, 8pm at our regular pub (Trödler).

A colleague of mine pointed me to a nice tool called Dropbox. 2GB of space in a cloud, intended to be used for sharing files and synchronizing files between computers.

Since yesterday I have Ubuntu 9.10 and also an Ubuntu One account which – from what I read – offers pretty much the same service.

Dropbox offers clients for Linux, Windows and Mac OS/X, but these clients are proprietary. Nevertheless I like the idea behind it because synchronizing my calendar and contacts between several clients and operating systems as well as being able to access this information with a web-frontend is still a top issue on my todo list – which I can synchronize now as well.

My plan is to have video conversations with my family, because I don’t see my sisters, brothers, niece, brother-in-law very often. So I got myself a Lifecam Cinema

The picture and sound quality is really great and it also works with Linux, e.g. in camorama.

I also tried Windows Messenger Live and I thought the adverts are annoying. There is a simply workaround, just add

127.0.0.1 rad.msn.com
127.0.0.1 rad.live.com

to your c:\windows\system32\drivers\etc\hosts and Messenger is not able to retrieve the commercials from the ad-server anymore.

My Thinkpad has a dual-boot setup, Windows and Ubuntu. I bought a copy of Windows 7 Professional and installed it this morning. Very smooth installation, nearly everything went out of the box, except the NVidia driver install. But harddrive AHCI mode was no problem, my WLAN card has been recognized and the install took only 30 minutes.

This is how Linux users had it for years! ^^

Of course the grub boot manager was gone after the install, fixed it by booting the Ubuntu DVD and doing

mkdir /mnt/root
mount -t ext3 /dev/sda6 /mnt/root
mount -o bind /dev /mnt/root/dev
mount proc -t proc /mnt/root/proc
chroot /mnt/root
mount -t ext3 /dev/sda2 /boot
grub-install /dev/sda

Yesterday evening the first real result was visible. Reception of DMX data and output of PWM on 8 channels is working now.

At the moment it’s only a development board.

All external parts are attached via loooong cables to other hardware.

A PCB Design is ongoing, but not all the details are yet clear for series production.

OKOK, that was maybe a little bit to short. First of all:

DMX: a strange protocol, that looks like it was intended to keep amateurs from building their own devices by adding a protocol error as start signal. But with todays µCs is possible, even though it’s a little bit ugly.

In my setup there is a light control desk which is the sender. So I only care about receiving at the moment.

The received 8 byte are saved in the µC and are the input data for the PWM generator.

Th PWM signal is used for PFC.

An external circuitry is used to detect the zero crossing of the 230V AC and based on the received DMX data triacs can be started.

Now that the basic functionality is working I can add service functions and error detection.

Jeff Bezos (CEO of Amazon) announced that the Kindle will be available in Europe real soon. Talk about my bad timing, I could have saved the shipping and import cost by simply waiting another month.

After these few days with the Kindle I think it’s a great product. The eInk display is like reading a real book.

There are some downsides however. The kindle is great for reading novels. I would really like online bookshops to provide a paperback version and for a small additional fee the eBook version of a book. This way, I could enjoy reading the “real” book and taking it with me on my eBook reader when I’m going on vacation. For technical books or newspapers the Kindle 2 display is too small.

DRM and converting different eBook formats into each other is the other drawback. This is certainly an issue and until now not a very customer-friendly approach.

Reboot for RAID reconfiguration and kernel upgrade.

This month's come together will be held on 2009-10-07, 8pm at our regular pub (Trödler).

Agenda: http://lisas.de/pipermail/luges/2009-October/005264.html

We started well with two 6:1 victories this weekend into the new season and we are now in 1st position. Today has been a long table tennis day, I also had to supervise the U15 and U18 boys. They did very well and won 6:3 and 6:2. This has been a lot of fun, 8 hours of table tennis, but a well spent Saturday.

I added a new page to this blog with a link list to free eBooks. As it turns out most people think free means free as in beer and not free as in speech. A lot of eBooks which are promoted to be “free” are in fact not, they are DRMed. This makes it a bit complicated if you want to convert PDF eBooks to the Kindle/Mobipocket file format. It is not impossible, though…

Of course I want. My ISP and telephone provider called today. They offer the same package for less money now and asked me if I wanted to pay less (~ €5 per month) for the same DSL and ISDN service. Only drawback is that I have to sign a contract for another 24 months. But I didn’t plan to switch the provider anyway so I accepted.

There are a lot of free eBooks available, unfortunately each eBook reader seems to have other preferences regarding the file formats. My new Kindle 2 doesn’t support the PDF format natively very well.

For the bravehearts out there, you can update your Kindle with Savory and it does support PDF and ePub conversion natively on the reader. I didn’t want to break my new fancy shiny toy on the second day, so I didn’t try it out.

For managing your eBook library, there is Calibre, a QT-based application, so it runs on Linux, Mac OSX and Windows. You can convert between many different eBook formats on your PC and then upload it directly to the reader or copy it via USB storage means. Calibre is also part of the Ubuntu Linux distribution and many other distributions.

This morning I have been at the customs office to get my Amazon Kindle 2.

Of course I had to pay an import tax. €62,32 – it’s not a cheap pleasure to import hardware. But it’s a great device and I already copied the first books from project Gutenberg to it.

From Linux it’s accessible as USB storage, so you can simply copy downloaded eBooks to the device.

Unfortunately it’s not possible to use the wireless feature in Germany because Amazon has still to find a phone company as partner.

USPprog (available here) is a very useful tool. I mainly use it as a AVRISP mk2 clone. This is done by flashing an AVRISP mk2 emulation firmware in the µC of the USBprog. Tools for doing that are available for the command line and also as GUI. I’ve ordered the parts together with some ATMega32 µCs and a prototype board. Since the USBprog consists of very few parts it can be easily soldered even by not so experienced users. The result looks like this:

The difficult part is to flash the boot loader SW on it. It’s a chicken/egg problem. I want to flash a SW on a µC that I want to use for flashing a µC. But with an old PC that has a parallel port it can be done.
After that I had a working USBprog. On the right you can see the USB port and on the left the cable used to connect to the µC.

Recently we bought a new TV, a Samsung LCD TV with full HD resolution. I was carefull getting a TV with a CI module slot, because we receive Sky (pay TV) and I didn’t want to buy a second receiver for the additional TV.

But unfortunatly there are no CI modules available which support NDS encryption which is used by Sky.



Removing the receiver from the setup in the living room and setting it up again in the bedroom each time wasn’t an option either. So I had to get this second receiver – but at least it supports HD via HDMI.

Having a complete PC is a good thing, but for controlling small things like a light it’s way too big and expensive, so I’ve decided to use smaller processors for that. After some research I ended up with the AVR micro controllers made by Atmel. They are easily available and affordabel  and what is even more important: An open source toolchain consisting of avr-gcc and avr-libc exists and even the hardware I’ll be using for programming the µCs is open source: USBprog.

I finally have mutt configured in such a way that it first tries to display the plain text part of a mail and only the HTML part if there is no plain text available. For years I had mutt configured to display HTML mails using lynx but it was displaying the HTML part even if there was plain text available.

To display HTML mails I was using auto_view text/html in my .muttrc like it is described everywhere with the following corresponding entry in my .mailcap:

text/html;      lynx -dump %s; copiousoutput; nametemplate=%s.html

The problem with this setup is that it displays the HTML part of a mail even if there is a plain text part available. So I had auto_view text/html disabled for most of the time and edited the configuration file manually to enable it again for the rare cases in which I received a HTML only mail.

But as this is mutt and almost everything can be configured I finally searched and found a solution:

auto_view text/html
alternative_order text/plain text/html

If the message has a plain text part and a HTML part mutt shows me the plain text part, but if there is only a HTML part available I get the HTML converted to plain text. Exactly what I always wanted.

With some help of Alex this is now working and I can say “Hello world”

Whatever blogs were originally invented for, I’ll use it mainly as a documentation tool for my struggles with the atmega32.