Debconf issue

If you have this: debconf: DbDriver "config": mkdir :No such file or directory You might just have deleted /var/cache/debconf. Solving this is easy: mkdir -f /var/cache/debconf apt-get -f install

May 18, 2013 · Florent Clairambault

Valgrind might be wrong

Sometimes valgrind can report the right problem with the wrong stack trace: make && sudo valgrind --db-attach=yes --leak-check=full --track-origins=yes --show-reachable=yes ./dist/Debug/cbadaemon ==4423== Memcheck, a memory error detector ==4423== Copyright (C) 2002-2011, and GNU GPL'd, by Julian Seward et al. ==4423== Using Valgrind-3.7.0 and LibVEX; rerun with -h for copyright info ==4423== Command: ./dist/Debug/cbadaemon ==4423== ==4423== Conditional jump or move depends on uninitialised value(s) ==4423== at 0x4922C47: __pthread_mutex_unlock_usercnt (pthread_mutex_unlock.c:38) ==4423== by 0x804E91A: ServerContext::ServerContext() (ServerContext....

April 24, 2013 · Florent Clairambault

SFR fibre

Latencies are really good :) --- ping statistics --- 10 packets transmitted, 10 received, 0% packet loss, time 9013ms rtt min/avg/max/mdev = 2.185/2.799/3.635/0.456 ms But I received an hadopi later. And still wish I knew why (there could be so many reasons).

March 10, 2013 · Florent Clairambault


Plex is great piece of software. It’s a “complete media solution”. I installed it on my laptop (free) without editing a single file, I tested it on my iPad (it’s a paid app) and it was just working instantly. Then I also tested it on my Nexus 7 (paid app on play store as well) and it’s also working perfectly. Then I discovered it can also do streaming through it’s web based interface, so it can stream to anything it doesn’t yet support....

February 25, 2013 · Florent Clairambault

Some good reasons for learning python

President Obama thinks required programming language learning in high school is a great idea. So do I, and I think we should all start with python. Writing code with it is very fast. When software engineers tell you “I can do it in 10 minutes”, in C/C++ they mean 4h, in java they mean 2h and in python they mean it. You can really do anything. I’ve done some serial communication, bit level manipulation, network level event-based servers, multithreading, webservice providing and consuming, SQL and cassandra client faster than what I’ve been doing in any other language....

February 21, 2013 · Florent Clairambault

Linux: restart when hung

When a Linux system crashes (usually because of a driver issue), you should make sure at least it restarts. These are the lines you should add to /etc/sysctl.conf: # Reboot time(s) after panic kernel.panic = 20 # Panic if a hung task was found kernel.hung_task_panic = 1 # Setup timeout for hung tasks to 30 seconds kernel.hung_task_timeout_secs = 30

November 26, 2012 · Florent Clairambault

Opensourcing the content of this blog

Hi everyone, During the last years, I launched the javacint google group which now has grown out to be a good community of professionnals working around the Cinterion (java enabled) chips. I also created a TC65 development document. And all the questions and feedbacks you gave me on the development around these chips helped me a lot to improve (what was) my document and (what was) my FAQ. You helped me so much indeed that I believe this content should know be open to everyone to modify....

August 6, 2012 · Florent Clairambault

xrdp and the ulimits / nofile issue

You might have noticed for xrdp on Debian (but quite possibly with a lot of other Linux tools and other Linux distributions) the user limits (described in /etc/security/limits.conf) are not enforced. Which meant in my case that any session open with xrdp was opened with a max number of open files (nofile) set to 1024. To fix this, edit the file /etc/pam.d/common-session and add the following line: session required

June 11, 2012 · Florent Clairambault

Limiting number of connections per IP with ufw

This is a personal reminder post. The easiest attack one can perform on a web server is opening all the connections and do nothing with it. iptables fortunately has a “connlimit” module to avoid this. If you’re using ufw like me you will want to keep your good integration with it. In the `/etc/ufw/before.rules file, after these lines: # Don't delete these required lines, otherwise there will be errors *filter :ufw-before-input - [:] :ufw-before-output - [:] :ufw-before-forward - [:] :ufw-not-local - [:] # End of required lines You can add this to limit the number of concurrent connections:...

June 2, 2012 · Florent Clairambault

Cassandra as registry

One of the biggest issue with distributed database is to find the right model to store your data. On a recent project, I decided to use a registry model. The registry idea The idea behind writing a registry is to have an easy way to both store and view data. For a given device that has a {UUID} id: I will access “/device/{UUID}/”. Any properties will be stored in “/device/{UUID}/properties/”....

June 1, 2012 · Florent Clairambault