Liebe Orchestermitglieder, liebe Interessenten, es geht wieder los! Wir freuen uns Euch mitteilen zu dürfen dass wir am Dienstag den 11.10.11  um 19h im Audimax mit unserm neuen Programm starten. Das sieht dieses Semester wie folgt aus:

• Debussy: Prelude à l’apres-midi d’un faune
• Schubert: Unvollendete
• Krizystof Penderecki: Allegretto aus “Paradise Lost”
• Grieg: Suite – 3 Orchesterstücke aus Sigurd Jorsalfar op.56 (Bühnenmusik)
• evtl: Marquez, Danzon No. 2

Ihr seht: ein spannendes und abwechslungsreiches Programm, das uns sicher viel Freude machen wird.

Neue Mitspieler sind herzlich eingeladen zu einer der ersten Proben zu kommen. Wir freuen uns über Verstärkung in allen Stimmgruppen, jedoch insbesondere bei den Streichern.

Liebe Orchestermitglieder, liebe Interes … Continue reading → Continue reading →

From time to time the VPN client integrated in Mac OS X keeps on failing to connect to our university VPN server. I searched for a long time and today I found the solution to restart the service without restarting my Mac (origin of the solution is here):

1. Open a Terminal and search for the racoon process

   Florian-Feldhauss-MacBook-Pro:~ ffeldhaus$ ps aux | grep racoon
   root     10495   0,0  0,0  2447088    672   ??  Ss   So11am    0:02.27 /usr/sbin/racoon

2. Now kill the racoon process

   Florian-Feldhauss-MacBook-Pro:~ ffeldhaus$ sudo kill 10495

3. At last, restart racoon

   Florian-Feldhauss-MacBook-Pro:~ ffeldhaus$ sudo /usr/sbin/racoon

From time to time the VPN client integra … Continue reading → Continue reading →

Recently my harddisk crashed and I used this opportunity to reinstall my system. Everything went fine, but getting my user certificates back turned out to be a bit tricky. For Grid Computing and administrating a Grid Site I need my certificates to be stored in the browser. As I recently renewed them, I haven’t done a backup of them (shame on me) so I couldn’t just reimport them in my newly installed Firefox 4 (beta). Here is what I did to get the certificates back from my old Firefox profile:

1. Find out where your profile folder is located. This Mozillazine Page might help.
2. Quit Firefox if it is still running
3. Go to the profile folder of your new Firefox installation and backup the files cert8.db and key3.db
4. Copy key3.db from your old profile folder to your new one if you want to restore your private/user certificates
5. Copy cert8.db from your old profile folder to your new one if you want to restore all other certificates you had installed in Firefox (e.g. root certificates and host certificates)

Recently my harddisk crashed and I used … Continue reading → Continue reading →

If you need to find out the number of CPUs or CPU cores or cores per CPU of your system, you could look it up in /proc/cpuinfo but it’s quite hard to figure out the right parameters. A good overview on the parameters for different system configurations can be found here. If you want to put the actual numbers in variables, here is a nice way to do it:

export CORES_PER_CPU=`grep -c "physical id.*: 0" /proc/cpuinfo`
export CPU_TOTAL=`grep -c "core id.*: 0" /proc/cpuinfo`
export CORE_TOTAL=`grep -c processor /proc/cpuinfo`

/proc/cpuinfo shows an entry for each CPU core. The physical id is incremented for each physical CPU. If the entry has the same physical id as another core, the core belongs to the same CPU. Therefore counting the number of entries with physical id set to 0 results in the number of cores per CPU. The core id is incremented for each core on a physical CPU. Therefore counting the number of entries with core id set to 0 results in the number of physical CPUs. The total number of cores can be retrieved quite easily by counting the number of processor entries.

Unfortunately the above method does not work on all systems. I noticed on some systems with single core processors, that the values core id and physical id are not present.

I searched for official documentation on the proc filesystem, but only found the following document which doesn’t describe the cpuinfo values:

• http://www.kernel.org/doc/Documentation/filesystems/proc.txt

If someone happens to know a better documentation I would be glad if he/she would share it with me!

If you need to find out the number of CP … Continue reading → Continue reading →

After the successfull restart of the LHC, the first collisions with two 3.5 TeV beams colliding at 7 TeV will take place on march 30th. From 8:30 till 18:00 (UTC+01) there will be a live webcast at

http://webcast.cern.ch/lhcfirstphysics/

The first collisions will probably take place between 9:00 and 11:00. The tentative schedule can be found here.

Update: An interesting page to watch the beam is the LHC Operations beam status page.

After the successfull restart of the LHC … Continue reading → Continue reading →

Debugging the SSL handshake can be lots of pain, especially if the SSL commands are done by components not under your control. Fortunately there is a tool called ssldump which lets you monitor the complete SSL handshake. The following command prints out detailed information about the SSL handshake (on interface eth0):

ssldump -a -A -H -i eth0

If you want to sneak at the encrypted traffic you need to tell ssldump where to find the hostkey (e.g. hostkey.pem or similar) of the machine

ssldump -N -d -k $PATH_TO_HOSTKEY/hostkey.pem -A -H -i eth0

Replace $PATH_TO_HOSTKEY and hostkey.pem accordingly.

More information can be found here or in the manpage of ssldump.

Debugging the SSL handshake can be lots … Continue reading → Continue reading →

Dr. Stefano Redaelli from CERN will hold two lectures on an overview of what happens when the LHC is in running mode. The lectures should be suitable for everyone with a bachelor or Vordiplom in physics or electrical engineering.They will take place in the CERN main auditorium at

• April 7, 10am-11am
• April 9, 10am-11am

More information can be found in the official announcement. If you happen to not be at CERN during that time, there will be also a webcast! As additional information on the webcast becomes available, I will post it here!

• The video of the first part of the lecture can be found here (choose “download movie->high res” to see all details of the slides).
• The video of the second part of the lecture can be found here (choose “download movie->high res” to see all details of the slides).
• The slides can be found here.

Dr. Stefano Redaelli from CERN will hold … Continue reading → Continue reading →

If you need to transfer big files, sometimes the network connection breaks down and you need to restart the transfer. Using the following command, you can start and resume (!) a file transfer:

rsync --partial --progress --rsh=ssh localFile username@remoteMachine:remoteDirectory/

If you generally want to use the above command add the following line to your ~/.bashrc and just use the new scpresume command:

alias scpresume="rsync --partial --progress --rsh=ssh

Many thanks to Joen.dk who came up with the idea!

If you need to transfer big files, somet … Continue reading → Continue reading →