Hi. I'm Jonas 'Sortie' Termansen. This is my personal website. I'm many things.
I'm widely recognized as an expert in the upcoming music scene in Denmark, scouting the shows of more than 300+ unique artists each year, having done so for more than five years now. I run the social media account @jonastermansen to identify and cover emerging artists years before they become mainstream. I know exactly what makes a great show, and which artists are ready to step up to the next level, and which ones to keep an eye on. I've seen more than 1000+ unique artists live in total, and I have exact data on every experience and every song I've heard thanks to my computer science background.
I interview emerging artists, particularly in connection with Uhørt festival. I offer services to artists, including performance coaching, feedback, photography, and videography. I attend performances of all sizes across the, world from the small venues like Ideal Bar, to the medium sized venues like Store Vega and Royal Arena, all the way up to the renowned international venues like the O2 Arena, Madison Square Garden, and The Greek Theatre. If it's the best show, I am there.
I've been invited onto DR P3 national radio several times as a music and festival expert. I've been on the front page of Aarhus Onsdag and Jyllandsposten with articles written about me, and I've had a documentary produced about me. I was invited to Dansk Melodi Grand Prix (Danish Eurovision) to be interviewed as part of the show. I'm always in the front row, getting the ultimate experience that the artist intended with full immersion. I'm always present at Roskilde Festival, Spot Festival, Uhørt Festival, and more in order to scout new artists, and inform the public about them. Many members of the Danish music business follow the instagram account and pay attention to which artists are covered.
I am a very skilled software engineer with expertise in low-level systems programming, security, testing, and infrastructure.
I received a generous grant from the NLnet Foundation to develop the os-test test suite for all POSIX operating systems. The project is made possible thanks to funding from the European Commission's Next Generation Internet programme. I presented my work at the FOSDEM 2026 conferfence in Bruxells, Belgium.
I've developed the new Unix-like operating system Sortix since 2011, and full time since 2025. It can be developed under itself after installation and it has ports of a lot of third party software, such as gcc, python, git, ssh, nginx, and a lot more. Sortix aims to be a clean and modern implementation of POSIX. It has its own base system written from scratch, including a kernel, C standard library and command line utilities.
I was a Software Engineer at Google Aarhus working on the Dart programming language on the Engineering Productivity Team:
See my resume for more details.
I graduated with a Bachelor's Degree in Computer Science from the University of Aarhus in 2016. I specialized in operating systems, security, and programming languages.
I made a couple video game mods with their own world and story. I love level design and world building.
The Islands mod for Fallout 4 contains a new game world that's 11% larger than the Nuka World DLC with 20 quests with an estimated 16 hours of play time, or 5 hours if you rush it.
Altered Transmission is a Half-Life 2: Episode Two single player campaign developed by me in 2007 and the years since. I've personally made all the level design of eighteen maps. The mod is not entirely finished but its latest published development snapshot is perfectly playable from start to finish.
I'm a very good C programmer. I have designed and implemented a ~90% complete libc written entirely from scratch based on the C and POSIX standards. This includes the support for error handling, memory management, signals, standard IO, strings, system calls, time, threads, unicode, wide characters, extensions from other operating systems and new extensions, and much more. It supports a lot of major software.
I can also work in C++, Dart, Scheme, Python, Java, Coq, PHP and a bunch of domain specific things.
I have a focus on software security and correctness.
I like Unix-like systems. I use Linux. I have a VM of every relevant free software POSIX system. I use git. I'm an expert at shell scripting and standard Unix build systems. I'm an expert at software portability and publish independent research. I've made toy HTTP servers and IRC bots. I typeset with LaTeX and write manual page in mdoc(7).
I'm experienced with systems programming, hardware drivers, assembly, filesystems, compilers, development tools, as well designing and implementing modern operating systems. I regularly use virtual machines.
I stop and inspect mysterious keypads that beep in strange patterns. It is fun to make sense of something you have no idea what is.
I'm a moderator at the osdev.org forums, a community and resource for experienced and aspiring operating system developers. I've written and improved lot of osdev wiki articles.
I occasionally write up stories of fun innocent ‘hacks’ I've done.
You can email me at sortie@maxsi.org.
I run my own irc.sortix.org IRC network as sortie.
I also frequent the IRC network libera as sortie. I idle in
channels such as ##fallout, ##posix, ##tty, #libz, #musl, #osdev.
I am @sortiecat on twitter.
I am jonastermansen on instagram.