Services and skills
On my home page, I explain that I'm technology-independent. However, every programmer has areas of expertise and it would be unwise to ignore those. Let me be clear about mine.
As one of the core developers of CHICKEN Scheme, I can tell you exactly how to write bulletproof and fast Scheme code. Don't hesitate to ask me anything!
After years of working with PostgreSQL databases, I know many subtle details that can save you a lot of time optimizing or designing your database.
More generally, you can invoke my help for any of the following services:
Building developer tools
Creating re-usable software libraries and general-purpose development tools is one of my spearheads. I love to rack my brain on simplifying complex underlying systems in elegant ways, so that you or your programmer can concentrate on that which is truly important: your application. Naturally, documentation in English (or in Dutch, if requested) is always provided.
Technical writing
Speaking of documentation, if you would like to explain a technical subject to a larger audience, you can feel comfortable assigning this task to me. I maintain a much visited blog called "More magic", where I distill complex subjects down to their essence. I explain things in an understandable way, often supported by clear diagrams and code examples.
To reach as many people as possible, English is a sensible choice, but I will also gladly write in Dutch. In that case I avoid unnecessary use of English terms.
System administration
I've managed Linux and BSD hosts for a long time. Specifically, I know my way around NetBSD, Red Hat/CentOS and Debian Linux systems. Tightening the security of these hosts is something I've done so often I can do it in my sleep.
Managing databases and web applications on these systems is not new to me either.
Troubleshooting
When you or your programmers get stuck on a particularly tricky bug it can be nice to get a fresh, independent perspective on the software. Debugging is not everyone's favourite activity, but I enjoy the challenge of puzzling out difficult problems. I will also gladly investigate performance problems in your application.