Sylvain Wallez


Random musings of a busy geek

Micro benchmarks can make you short-sighted

In the last 24 hours, two articles related to code benchmarking showed up on my Twitter timeline, where the authors describe the optimization of a tiny bit of code via successive benchmarks. Both articles immediately triggered the same reaction in my head: "WTF, this is wrong! Why did they wrote ...


Afternoon hack: a USB foot keyboard

This post explains a quick afternoon hack to turn a foot pedal controller for music synthesizers into a programmable USB foot keyboard. A couple of weeks ago, for a personal project, my wife needed to manually transcribe many hours of interview recordings. Text-to-speech software were failing miserably both because of ...


Blog.reboot()

This blog is now a static website powered by the Pelican generator. It's the 3rd major change since I started blogging in 2002. It began with Movable Type, a Perl blogging tool. There wasn't much choice at that time, and it did the job even if I did ...


Efficient storage of non-periodic time series with MongoDB

TL;DR: this post explains the MongoDB storage structure we use at Actoboard to efficiently store non periodic time series. Storing one Mongo document for each data point is woefully inefficient, so we store them in fixed-size segments, which speeds things up by more than an order of magnitude. MongoDB ...


GitHub hack: a common security flaw in webapp frameworks

GitHub has faced a spectacular hack: a disappointed developer has exploited a weakness in Ruby on Rails to gain commit access to the Rails master branch and create issues in the future. As a result, GitHub asks us to confirm our ssh keys, but this can have been used to ...


My 2011: a year like no other

This blog has been mostly silent in 2011. Blame both Twitter that makes capturing quick thoughts so easy and a busy year as I started my freelance business. But a new year is starting, and along with the traditional wishes I owe an update to the people that still look ...


How often do you redeploy your J2EE application?

The guys at ZeroTurnaround have published an interesting report on the development habits from over 1300 Java developers. One of the questions that really struck me was "how often do you redeploy?" My answer to this question is "on my development machine, never". I use Jetty which is really easy ...


New year, new job

It's been 2 months since I left my previous job. I used this time to get some rest, think about what I wanted to do next, meet people and have lots of discussions. I've also been questioning myself if it was time to join a larger company and ...


My last day at Goojet

Today was my last day at Goojet. I've been the CTO there since april 2008, and have been involved informally with their team since even before the company was created in 2007. As in every startup, there has been ups and downs, incredible times with an amazing creative energy ...


Today is the answer to Life, the Universe and Everything

Warning: super-geeky stuff ahead :-) Today is October 10, 2010, or in other words 10-10-10. This is in itself a noticeable date, but it gets even more interesting when you consider that 101010 is the binary value for 42! So today is not only 10-10-10, but also the day of the ...