You have reached, Marco van Zwetselaar’s professional domain. I’m also at, my family’s long time personal digital namespace.

Who is

My professional career started in academic research deep in the past millennium. Then there was a twenty year stint in commercial IT (details). I then moved back into research, and have since been immersed in genomics and bioinformatics. After ten years building from scratch KCRI’s bioinformatics unit, I moved on in March 2023 to continue as an independent contractor with my own company (Zwets IT). Read my full CV here.


I tremendously enjoyed setting up the bioinformatics unit at KCRI in Moshi, Tanzania. This meant single-handedly building an affordable but adequate high-performance cluster (, developing pipelines such as the KCRI CGE Bacterial Analysis Pipeline (BAP), teaching basic and advanced bioinformatics courses, and performing countless analyses for projects around Africa – including Tanzania’s first and only published SARS-CoV-2 genomes. I hope to continue in this line of work, building local bioinformatics capacity at other sites in Africa.


Bioinformatics is my work, programming is my craft and passion. I must have typed my first line of BASIC circa 1979 on a Philips P2000. Then came Pascal, LISP and C++ in the 80s – as well as an obscure DBase3 language which is all but lost in the haze. I then rode the third AI wave of the early 90s, picking up Prolog and Scheme, and a heap of mathematical statistics in the wake of the newborn field of “Neural Networks”. The beautifully austere formalisms of lambda calculus and combinatory logic blew my mind and cemented my love for functional languages. Haskell is still my favourite programming language, by far.

Ah, work

When play time university was over, I spent the 90s and 00s professionally cranking out uncountable lines of C, C++ and Java. My work gradually shifted to consulting and architecture (see CV), but even as an enterprise architect I didn’t give up coding altogether.1 I saw the dawn and dusk of the dark ages of XML; I witnessed the rise of Javascript and the second coming of Python.

My current day-to-day languages are Bash/GNU, Python, C++ and (reluctantly) R. I’m open to programming assignments, provided they involve no front-end work and can be done with open source tools, on Linux.


I started this site when GitHub enabled personal domains for pages. I already owned, the io stuck, and so it became Apart from the geeky pun, ask any Italian why I/O makes sense.

  1. Recreational excursion tips: Erlang, Newspeak, Pure, Parallel Brainfuck.