About

Born in the 70th, yet ageless, and this is the place where I occasionally share my notes, thoughts and tutorials about open source, BSD and GNU/Linux system administration, and programming - the pragmatic way.

Please forgive any shortcomings and mistakes on this website. Also, English is not my native language.

I am the author of PHP The Wrong Way, OpenBSD Router Guide and Programmering i Go (a Danish Go programming tutorial that I hope I have the time to finish some day).

I started programming in BASIC on the Sharp MZ-800 when I was about 9 or 10 and I have been passionately interested in computers and programming since then. :)

I had my first computer related job when I was only 15 years old in a security and communications company working primarily with modems and 10BASE2 Ethernet systems. There I learned a lot about soldering, electronics, and programming in machine code. It was a real dream job for a 15 year old kid :)

I almost became an electronic engineer, but I never finished the last part of my studies because I was too busy working. Therefore I am mostly self-taught.

Most of my life I have been working as a system and network administrator and programmer, both as an employee, as an independent business owner, and as a freelance consultant.

I am a passionate proponent of open source, and of making systems simple, clear, secure and very performant.

I am absolutely allergic to applications and system setups that have been put together by following hype and trends.

Whenever I am involved in a project I try to follow good software engineering principles such as:

• Simplicity: The system should always be as simple and small as possible. When software projects grow, so do errors and bugs. Techniques such as line-by-line inspection of software, relevant unit testing, and physical examination of hardware that implements protection mechanisms are great. For such techniques to be successful a small and simple design is essential. This is sometimes described as the KISS principle and YAGNI.
• Least privilege: Each user and program should operate using the fewest privileges possible.
• Open design: In order for a system to be secure it must never depend on attacker ignorance. Instead the design should be based upon technology that depend upon public scrutiny - whenever possible.
• Complete mediation: Every access attempt must be checked and validated.
• Easy to use: The human interface must be as easy and intuitive to use as possible. Easy and simple is always better than smart and fancy. Simple user testing is a great way to get valuable feedback.
• Usability: Well known usability standards should be met if required.
• Discrimination: User discrimination is never good. User discrimination is when an application only works for a limited amount of systems or setups, like when a website only works with JavaScript enabled even though it doesn't provide any functionality that really requires JavaScript.
• Documentation: Lacking or inadequate documentation is a bug. Everything needs to be adequately documented from the very beginning, it is an integrate part of software development.