Conference report: FOSDEM 2020

On the first two days of February, I attended and presented at the 20th edition of FOSDEM – the annual Free and Opensource Developers’ European Meeting in Brussels, Belgium.


FOSDEM bills itself as the best Opensource conference in Europe. It has always been held in Brussels and, to my knowledge, always at Université libre de Bruxelles (The Free University of Brussels) – an apt venue, indeed.

The conference is absolutely free for everyone to attend. It’s paid for by donations, sponsors (who have booths), and the sale of merchandize. 

This year marked the 20th anniversary of the conference. I couldn’t have chosen a better first time to attend. The talks (and especially the closing keynote) offered a healthy dose of reminiscence that captured the ethos of the OSS community in Europe and beyond.


A conference with 4000 attendees, dozens of tracks, and more than 400 hours of content spread over two full days is bound to have a jam-packed program. Check out the Saturday and Sunday schedules … try to not be overwhelmed! 

Many of the talks were delivered in full rooms. Even the large lecture hall at the University was packed to the rafters for a few talks. The conference organizers had to put up “Full” signs on the outside of the doors (for fire-safety reasons) to dissuade people from entering the rooms.

Given the sheer number of talks, there was no way any one person could even attend a fraction of them. I’m happy and grateful to the organizers that they’ve made most of the talks available online.

My overwhelming feeling was a mixture of equal parts awe, marvel, and discomfort. The conference was very crowded and therefore, a bit chaotic. This is not meant to slight the organizers and volunteers, who did a superhuman task in ensuring the safety of people during ingress/egress, announcing schedule changes, and being very helpful with logistical questions. It’s only natural that a conference with 4000+ people held over a weekend in a rainy city is going to get occasionally messy. I loved every bit of it: the size, the number of passionate software people, the self-organizing crowds, the occasional changes to plan, and even the shoulder-rubbing discomfort. It was all an apt metaphor for open source software itself!

Synopsis of Talks I attended

Thorsten Leemhuis’s Keynote

The Saturday morning keynote by Thorsten Leemhuis was a great start to the conference. Thorsten talked about the evolution of the Linux kernel and how it has gained features through accretion. The way the BKL (Big Kernel Lock) was eliminated from the kernel over the years – opening up scaleability possibilities – is emblematic of how the Linux kernel evolves: slowly, discontinuously, and even unpredictably. 

Another interesting evolutionary pathway was how virtualization was added to the Linux kernel. The Xen project, led by Lars Kurth (also see “Memoriam” below) was an early attempt at virtualization. Over time, KVM became more successful and powerful. KVM succeeded because 1) Xen took a while to come up, and also 2) KVM is built into Linux, not a bolt-on.

In terms of wishlist items, Thorsten mentioned improved tracing and observability (BCC, bpftrace/ DTrace 2.0) and the work being done by Brendan Gregg. This is a field that has had slow yet steady performance for 10+ years – typical of how things work in a large OSS like the Linux kernel. Another wishlist item was realtime capabilities. (Thorsten reminded us that realtime is primarily about predictability; not performance.) 

The distributed nature of decision-making in how the Linux kernel evolves – no central “design by committee – makes things both unhindered and also ungoverned. With good ideas and commitment, big and crazy things can be accomplished.

Is The Open Door Closing?

Kryzystof Daniel asked the question ”Is the Open Door Closing?“ in his talk. This statement of his is worth quoting:

“Opensource software is like a halting problem: all OSSes fail, we just don’t know when.” – Krzystof Daniel

Krzystof said that OSS was born in response (and in reaction) to copyright. He sounded the cautionary note that if someone advocates turning your project into an OSS, be wary: it’s probably beneficial for them and not so much for you.

The Core Values of Software Freedom

Matthias Kirschner of FSFE spoke on the core values of software freedom. He took a pragmatic approach and said that to achieve a greater good (i.e. more and better OSS), we have to work with people who may not share all the ancillary values that we may have. In particular, he said that the “Free” in software is not about money: you may make money from free software if you please (and if you can). This is consistent with the “four freedoms” implied in the definition of Free Software, and summarized as the freedom to usestudyshare, and improve software without let or hindrance.

Why Open Infrastructure Matters

Thierry Carrez dilated on the benefits and necessity of open infrastructure. He cautioned against the dangers of monocultures, and emphasized the three C’s: capabilitiescompliance, and cost.

Free software needs free tools. – Benjamin Mako Hill

Why GPL is Great for Business

Frank Karlitschek’s observation on how Gnu Public License is the right vehicle to promote business software was fascinating for me. Basing his argument on the “four freedoms” and the “ten criteria” of free software, he described several commercial OSS models that don’t work. He then highlighted the benefits of using GPL for commercial software, using Nextcloud as an example.

FOSDEM@20 – A Celebration

Steven Goodwin’s closing keynote was a funny and absorbing recap of the 20 years of FOSDEM – or as he reminded us, the first year of OSDEM and the last 19 of FOSDEM. Steven has attended every one of those twenty years and has captured his recollections in his FOSDEM diaries. He shared a screenshot of an e-mail from December 2000 that started it all. The e-mail began thus: 

I hope you don’t consider it spam … – Raphaël Bauduin

It was wonderful to see Raphaël join Steven on the stage and kibitz with him. Raphaël unveiled his 20-year-old T-shirt – a bit worse for wear but still a good fit – to the audience’s merriment and applause.

Steven summed up the ethos of FOSDEM: Start small and keep it free. Free is good.

My Talk

My talk was the last one (18:15 – 19:00) on Saturday, Feb 1st. 

I had a packed room – the “Full” sign that the organizers put at my door was humbling. The turnout was fabulous, especially given the late hour, and I appreciated everyone participating in the two activities with noisy vigor!

Networking and Socializing

With a crowd of 4000+ people, networking is actually a challenge. There are just too many people to strike up a meaningful conversation.

Piet de Visser and I had a good chat about Germany, Databases, and FOSDEM while waiting in line for coffee.

Riana Franklin Allen attended my talk and sent me a delightful message later saying she’ll share it with her coworkers. Thanks a bunch, Riana!

Elio RojanoPablo Martinez and André Jaenisch also attended my talk and tweeted about it. Thank you, all!


It was sad that Lars Kurth passed away days before the conference. There was a session dedicated to him (I didn’t attend in person). Requiescat in pace, Lars.