Operating systems

I almost exclusively use Linux at home and as development platform at work. I have some experience administering Linux servers and workstations. I follow recent Linux and general open source development by reading LWN.net and similar news sites. In the past I also used Windows and other free Unix variants such as FreeBSD, NetBSD and OpenBSD.

Programming languages (general)

My main programming language is Ruby. It is my first choice for almost every new project and also small tasks. I am also quite proficient in C, PHP, SQL and PL/pgSQL. I have some experience in Lua, mostly from writing scripts for nmap, the open source security scanner. Other languages I looked at are, amongst others, Javascript, Java, C++, XSLT, Python, Perl, Prolog and Dylan. I am quite quick at picking up a new programming language.

Ruby

I have about 5 years worth of experience with Ruby. I am very enthusiastic about it and know the language and the standard library. I used advanced techniques like metaclasses, runtime class and function generation. I am quite proficient with the Rails web application framework.

SQL

I have about 6 years worth of experience with SQL. I almost exclusively worked with PostgreSQL during this time but I also looked at other database management system like MySQL, SQLite and Sybase amongst others. I am also proficient in writing stored procedures in PL/pgSQL.

Freelancer (since May 2007)

Among other things, I implemented a generic logging framework for Pentabarf, rewrote the authorization system and customized Pentabarf.

CCCV GmbH ( August 2005 - January 2006 )

I did an internship at CCCV GmbH.

My main task was to port the Pentabarf conference planning system from PHP to Ruby and the Rails web application framework.

Pentabarf

Pentabarf is a conference planning software written in Ruby and PL/pgSQL. It uses the Rails web application framework. Pentabarf has been used by more then 60 conferences so far. Pentabarf has been started as planning tool for the 21C3 in 2004. Initially it was written in PHP but it has been rewritten in Ruby and Rails. It uses PostgreSQL as database backend. I am the lead developer of pentabarf.

momomoto

Momomoto is an object relation mapper for PostgreSQL written in Ruby. It is used in Pentabarf as an ActiveRecord replacement.

nmap

Nmap is a network security scanner. I contributed Lua bindings for openssl and wrote quite a few scripts in Lua, amongst others scripts for RPC, SSH1 and SSH2. Nmap is written in C++ and nmap scripts are written in Lua.

Others

There are several other smaller projects probably not worth mentioning here. They are mostly written in Ruby, Lua or C. I also submitted patches to several Open Source projects some of which got included.