Ciro Santilli  Sponsor 中国独裁统治 China Dictatorship 新疆改造中心、六四事件、法轮功、郝海东、709大抓捕、2015巴拿马文件 邓家贵、低端人口、西藏骚乱
Ciro Santilli's definition:
Ciro's tutorial: Linux Kernel Module Cheat.
Ciro's word of caution for 2019 aspiring system programmers: Should you waste your life with systems programming?
This is basically a direct consequence of backward design.
The higher the level you can operate at, the better.
C is better than assembly, userland better than kerneland.
The ideal level to operate at, and one of humankind's greatest ambitions is "AGI, make me money", the highest possible level.
Only go down a level when it seems necessary.

Operating system (OS)

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Magic software that allows you to write a single program that runs on a wide range of hardware.

Bare metal

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Bare metal programming is to run a program without an operating system below it.
Or in other words, it is basically implementing an operating system/firmware yourself ad hoc, together with your actual program.

Embedded operating system

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Zephyr (Operating system)

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Zephyr is cool. Its installation setup is annoying. But the project is cool.
Real hardware is for newbs. Real hardware is for newbs.
Tested on Ubuntu 23.10 we approximately follow instructions from: stopping before the "Flash the sample" section, as we don't flash QEMU. We just run it.
sudo apt install --no-install-recommends git cmake ninja-build gperf \
  ccache dfu-util device-tree-compiler wget \
  python3-dev python3-pip python3-setuptools python3-tk python3-wheel xz-utils file \
  make gcc gcc-multilib g++-multilib libsdl2-dev libmagic1
python3 -m venv ~/zephyrproject/.venv
source ~/zephyrproject/.venv/bin/activate
pip install west
west init ~/zephyrproject
cd ~/zephyrproject
west update
west zephyr-export
cd ~
tar xvf zephyr-sdk-0.16.1_linux-x86_64.tar.xz
cd zephyr-sdk-0.16.1
The installation procedure install all compiler toolchains for us, so we can then basically compile for any target. It also fetches the latest Git source code of Zephyr under:
The "most default" blinky hello world example which blinks an LED is a bit useless for us because QEMU doesn't have LEDs, so instead we are going to use one of the UART examples which will print characters we can see on QEMU stdout.
Let's start with the hello world example on an x86 target:
cd ~/zephyrproject/zephyr
west build -b qemu_x86 samples/hello_world -t run
and it outputs:
Hello World! qemu_x86
The qemu_x64 on the output comes from the CONFIG_BOARD macro
#include <zephyr/kernel.h>

int main(void)
	printk("Hello World! %s\n", CONFIG_BOARD);
	return 0;
The qemu_x86 board is documented at:
You can also first cd into the directory that you want to build in to avoid typing samples/hello_world all the time:
cd ~/zephyrproject/zephyr/samples/hello_world
zephyr west build -b qemu_x86 -t run
You can also build and run separately with:
west build -b qemu_x86
west build -t run
Another important option is:
west build -t menuconfig
But note that it does not modify your prj.conf automatically for you.
Let's try on another target:
rm -rf build
zephyr west build -b qemu_cortex_a53 -t run
and same output, but on a completely different board! The qemu_cortex_a53 board is documented at:
The list of all examples can be seen under:
ls ~/zephyrproject/zephyr/samples
which for example contains:
So run another sample simply select it, e.g. to run zephyrproject/zephyr/samples/synchronization:
west build -b qemu_cortex_a53 samples/synchronization -t run


articles: 1


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It ain't perfect, but it's decent enough.
From a technical point of view, it can do anything that Microsoft Windows can. Except being forcefully installed on every non-MacOS 2019 computer you can buy.
Ciro Santilli's conversion to Linux happened around 2012, and was a central part of Ciro Santilli's Open Source Enlightenment, since it fundamentally enables the discovery and contribution to open source software. Because what awesome open source person would waste time porting their amazing projects to closed source OSes?
Ciro's modest nature can be seen as he likes to compare this event Buddha's Great Renunciation.
Linux should track glibc and POSIX command line utilities in-tree like BSD Operating System, otherwise people have no way to get the thing running in the first place without blobs or large out-of-tree scripts! Another enlightened soul who agrees.
Particularly interesting in the history of Linux is how it won out over the open competitors that were coming up in the time: MINIX (see the chat) and BSD Operating System that got legally bogged down at the critical growth moment.
You must watch this: truth Happens advertisement by Red Hat.
Figure 1.
xkcd 619: Supported Features
. Source. This perfectly illustrates Linux development. First features that matter. Then useless features.
Video 1. . Source. Just stop whatever you are doing, and watch this right now. "I'm on Linux, bitch, I thought you GNU". Fandom explanations. It is just a shame that the Bill Gates actor looks absolutely nothing like the real gates. Actually, the entire Gates/Jobs parts are good, but not genial. But the Linux one is.

Linux kernel

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Ciro Santilli has a tutorial at Linux Kernel Module Cheat.
The fact that this foundation has a bunch of paid, closed, certification courses makes Ciro Santilli not respect them at all. They should be making open access content instead!
Linux insides
words: 15
Documents the Linux kernel. Somewhat of a competitor to Linux Kernel Module Cheat, but more wordy and less automated.
Step debug the Linux kernel
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articles: 1

Linux distribution

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As of 2020, no one knows how to build the major desktop distros fully from source into the ISO, and especially so in a reproducible build way. Everything is done in build servers somewhere with complicated layers of prebuilds. It's crap.
See also:
Cross distro package manager
words: 13 articles: 3 has some very good comments on how snap is more closed than Flatpak.

List of Linux distributions

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Android (operating system)
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However, many, many, many terrible horrors come with it:
The video folder is DCIM/Camera.
Arch Linux
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Respect. Big respect. Those people are hardcore from scratch hackers, and their wiki is amazing:
It's just that Buildroot is more hardcore ;-)
But can you build the ISO full from source: Linux distribution buildable from source
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The basis for Linux Kernel Module Cheat.
Buildroot is good.
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This thing is sexy.
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Ciro Santilli's Linux distro of choice as of 2019.
It ain't perfect, but it's decent enough.
The greatest advantage of it being that it has the likely largest desktop user base, and therefore the highest likelihood that your problems are solved on Ask Ubuntu, and goes together with Ciro's philosophy that "people should do everything in the same way to factor stuff out", especially the open source losers.
Ciro considers that the killer flaw of Ubuntu, and most desktop distros of 2020, is that no one under the Sun knows how to build them fully from source: Linux distribution buildable from source. This is why Ciro based the Linux Kernel Module Cheat on Buildroot, see also: Linux distribution buildable from source.
apport (software)
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Source code:
Ubuntu HOWTO
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On Ubuntu 23.10, a crash led to the creation of:
After that simply running apport-cli as:
apport-cli gnome-shell
led to the creation of: a bug on the gnome-shell package.
Their crash system does not have an amazing user interface.
Tested on Ubuntu 21.10.
After something crashes, look under /var/crash for a crash file, which helps to determine which package to report under on Launchpad.
E.g. a file /var/crash/_usr_sbin_gdm3.0.crash makes you want to file the bug under gdm at:
Then, while reporting the bug, you want to give the developpers access to that .crash file. But you can't publicly upload it because it contains memory dumps and could contain secret information. The way to do it is to look at the ID under:
sudo cat /var/crash/_usr_sbin_gdm3.0.uploaded
Ubuntu's crash report system has already uploaded the .crash for you, so you just have to confirm it and give the ID on the ticket.
You can view a list of all your uploaded errors at:
xdg-open$(sudo cat /var/lib/whoopsie/whoopsie-id)
and each of those contain a link to:<.uloaded error id>
which you yourself cannot see. asks how to read the .crash files.
sudo apport-unpack /var/crash/_usr_sbin_gdm3.0.crash /tmp/app
splits it up into a few files, but does not make any major improvements.
sudo apt install apport-retrace
sudo chmod 666 /var/crash/_usr_sbin_gdm3.0.crash
apport-retrace -g /var/crash/_usr_sbin_gdm3.0.crash
opens GDB with the core dump. Debug symbols are supplied as separate packages, which is a really cool idea: so you should be able to download them after the crash to see symbols. mentions how to install them. Official docs at:
echo "deb $(lsb_release -cs) main restricted universe multiverse" | sudo tee -a /etc/apt/sources.list.d/ddebs.list
echo -e "deb $(lsb_release -cs)-updates main restricted universe multiverse\ndeb $(lsb_release -cs)-proposed main restricted universe multiverse" | sudo tee -a /etc/apt/sources.list.d/ddebs.list
sudo apt install ubuntu-dbgsym-keyring
but then sudo apt update fails with:
E: The repository ' impish-security Release' does not have a Release file.
Ubuntu release
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Ubuntu 24.04
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Ciro Santilli reproduced on Dell Inspiron 15 3520 with factory defaults. This bug prevents "wipe windows" installation without workarounds, one of which is to disable encryption in Windows.
Happens at startup without doing anything, and then keeps happening randomly infinitely many times... on a almost clean 24.04 ISO install on Dell Inspiron 15 3520... God how can it be so bad.
Viewing the apport issue a bit further shows title:
nautilus crashed with sigabrt in g_assertion_message_expr
Possibly related:
Ubuntu 23.10
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Had this happen on P14s on Ubuntu 23.10 while causally using Chromium. The screen went blank for a few seconds, but it apparently managed to reboot itself, and things started working again, except that and most windows were killed:
[drm:gfx_v11_0_priv_reg_irq [amdgpu]] *ERROR* Illegal register access in command stream
[drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx_0.0.0 timeout, signaled seq=5774109, emitted seq=5774111
[drm:amdgpu_job_timedout [amdgpu]] *ERROR* Process information: process chrome pid 14023 thread chrome:cs0 pid 14087
amdgpu 0000:64:00.0: amdgpu: GPU reset begin!
[drm:mes_v11_0_submit_pkt_and_poll_completion.constprop.0 [amdgpu]] *ERROR* MES failed to response msg=3
[drm:amdgpu_mes_unmap_legacy_queue [amdgpu]] *ERROR* failed to unmap legacy queue
[drm:mes_v11_0_submit_pkt_and_poll_completion.constprop.0 [amdgpu]] *ERROR* MES failed to response msg=3
[drm:amdgpu_mes_unmap_legacy_queue [amdgpu]] *ERROR* failed to unmap legacy queue
[drm:mes_v11_0_submit_pkt_and_poll_completion.constprop.0 [amdgpu]] *ERROR* MES failed to response msg=3
[drm:amdgpu_mes_unmap_legacy_queue [amdgpu]] *ERROR* failed to unmap legacy queue
[drm:mes_v11_0_submit_pkt_and_poll_completion.constprop.0 [amdgpu]] *ERROR* MES failed to response msg=3
[drm:amdgpu_mes_unmap_legacy_queue [amdgpu]] *ERROR* failed to unmap legacy queue
[drm:mes_v11_0_submit_pkt_and_poll_completion.constprop.0 [amdgpu]] *ERROR* MES failed to response msg=3
[drm:amdgpu_mes_unmap_legacy_queue [amdgpu]] *ERROR* failed to unmap legacy queue
[drm:mes_v11_0_submit_pkt_and_poll_completion.constprop.0 [amdgpu]] *ERROR* MES failed to response msg=3
[drm:amdgpu_mes_unmap_legacy_queue [amdgpu]] *ERROR* failed to unmap legacy queue
[drm:mes_v11_0_submit_pkt_and_poll_completion.constprop.0 [amdgpu]] *ERROR* MES failed to response msg=3
[drm:amdgpu_mes_unmap_legacy_queue [amdgpu]] *ERROR* failed to unmap legacy queue
[drm:mes_v11_0_submit_pkt_and_poll_completion.constprop.0 [amdgpu]] *ERROR* MES failed to response msg=3
[drm:amdgpu_mes_unmap_legacy_queue [amdgpu]] *ERROR* failed to unmap legacy queue
[drm:mes_v11_0_submit_pkt_and_poll_completion.constprop.0 [amdgpu]] *ERROR* MES failed to response msg=3
[drm:amdgpu_mes_unmap_legacy_queue [amdgpu]] *ERROR* failed to unmap legacy queue
[drm:gfx_v11_0_cp_gfx_enable.isra.0 [amdgpu]] *ERROR* failed to halt cp gfx
Dec 27 15:03:38 ciro-p14s kernel: amdgpu 0000:64:00.0: amdgpu: MODE2 reset
Dec 27 15:03:38 ciro-p14s kernel: amdgpu 0000:64:00.0: amdgpu: GPU reset succeeded, trying to resume
Dec 27 15:03:38 ciro-p14s kernel: [drm] PCIE GART of 512M enabled (table at 0x0000008000900
It appears to be a bug in the AMDGPU open source driver.
Related reports:
I think this was on Wayland. Possibly relatd but on X Window System, crashed the UI, showed message "oh no! Something has gone wrong."
2024-01-13_21-55-07@ciro@ciro-p14s$ cat /var/log/apport.log
ERROR: apport (pid 975172) 2024-01-13 21:41:02,087: host pid 3528 crashed in a separate mount namespace, ignoring
INFO: apport (pid 975227) 2024-01-13 21:41:02,398: called for pid 2728, signal 5, core limit 0, dump mode 1
INFO: apport (pid 975227) 2024-01-13 21:41:02,401: executable: /usr/bin/gnome-shell (command line "/usr/bin/gnome-shell")
INFO: apport (pid 975227) 2024-01-13 21:41:12,667: wrote report /var/crash/_usr_bin_gnome-shell.1000.crash
Happened on P14s on Ubuntu 23.10, which started with fresh Ubuntu 23.10 install.
However it did not happen on Lenovo ThinkPad P51 (2017) also on Ubuntu 23.10 which had been upgraded several times from God knows what starting point... At first one had X11 (forced by Nvidia drivers) and the other Wayland, but moving to p14s X11 changed nothing.
Both were running GNOME Display Manager.
Same happens with Super + L, but also CLI commands:
Ubuntu 23.04
words: 90 articles: 1
On Lenovo ThinkPad P51 (2017).
Switching to the other installed kernel, 5.9 made boot work.
The solution on kernel 6.2 was:
sudo apt instal nvidia-driver-515
as per comments under: This also made the nvidia driver work: Find GPU information in Ubuntu.
Previously I had:
and it blew up before reaching disk decryption.
I also tried:
but that broke in a different way:
Finished apport-autoreport.service - Process error reports when automatic reporting is enabled.
nvidia-modeset: ERROR: GPU:0: Idling display engine timed out: 0x0000947d:0:0:407
(1 of 2) Job systemd-backlight@backlight: nvidia_e.service/start running (32s no limit)
Some threads:
Ubuntu 22.04
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Happening multiple times a day on Ubuntu 22.04 for Chromium, even though I turn computer on and off daily, unbearable:
Ubuntu 21.10
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GDM crashes sometimes when switching windows right after opening a new window:
Please refer to Video "Linus Torvalds saying "Nvidia Fuck You" (2012)".
Reported at:
On Lenovo ThinkPad P51 (2017).
Does not happen every time, only some times. Can't figure out why. Usually happens when has suspended for a longer time. sounds like a likely report, Nvidia driver version 470, but can't find those error messages anywhere. The last line of:
journalctl -o short-precise -k -b -1
once was:
PM: suspend entry (deep)
which is when sleep starts.
This suggests that it is not a video bug then, seems that it is not waking up at all? Gotta try to SSH into it. OK. I did SSH into it, and that was fine, so it is just the video that won't start.
PM: suspend exit is another possible bug, based on kernel version. I'm running 5.13, which is one of the failing versions on the report. Can't find any interesting dmesg though.
In another crash:
journalctl -o short-precise -k -b -1
had the following interesting lines:
nvidia-modeset: WARNING: GPU:0: Lost display notification (0:0x00000000); continuing.
[24307.640014] NVRM: GPU at PCI:0000:01:00: GPU-18af74bb-7c72-ff70-e447-87d48378ea20
[24307.640018] NVRM: Xid (PCI:0000:01:00): 79, pid=8828, GPU has fallen off the bus.
[24307.640021] NVRM: GPU 0000:01:00.0: GPU has fallen off the bus.
[24328.054022] nvidia-modeset: ERROR: GPU:0: The requested configuration of display devices (LGD (DP-4)) is not supported on this GPU.
[repeats several more times]
[24328.056767] nvidia-modeset: ERROR: GPU:0: The requested configuration of display devices (LGD (DP-4)) is not supported on this GPU.
[24328.056951] nvidia-modeset: ERROR: GPU:0: Failed to query display engine channel state: 0x0000927c:0:0:0x0000000f
[24328.056955] nvidia-modeset: ERROR: GPU:0: Failed to query display engine channel state: 0x0000927c:1:0:0x0000000f
[24328.056959] nvidia-modeset: ERROR: GPU:0: Failed to query display engine channel state: 0x0000927c:2:0:0x0000000f
[24328.056962] nvidia-modeset: ERROR: GPU:0: Failed to query display engine channel state: 0x0000927c:3:0:0x0000000f
[24328.056983] nvidia-modeset: ERROR: GPU:0: DP-4: Failed to disable DisplayPort audio stream-0
[24328.056992] nvidia-modeset: ERROR: GPU:0: Failed to query display engine channel state: 0x0000947d:0:0:0x0000000f
and there was a corresponding /var/crash/_usr_sbin_gdm3.0.crash.
Related "GPU has fallen off the bus":
Ubuntu feature request
words: 99 articles: 2
Sometimes it just feels like Ubuntu devs don't actually use Ubuntu as a desktop.
Some extremelly anoying problems are introduced and just never get fixed, even though they feel so obvious!
Would never happen on Mac...
This BS started after the move to ZFS. The temporary solution appears to be:
And then this to disable automatic snapshots in the future:
sudo mv /etc/apt/apt.conf.d/90_zsys_system_autosnapshot /etc/apt/apt.conf.d/90_zsys_system_autosnapshot.disabled
God, this is so annoying:
This has annoyed Ciro Santilli for many years, it is just too wasteful of screen space on laptops!
Or likely more generally, on GNOME desktop, which is the default desktop environment as of Ubuntu 22.10.
Legal issues stalled them at the turning point of the Internet, and Linux won. Can't change history.
Did Apple just fork it and made Mac OS X without giving anything back?


words: 79 articles: 14
The real explanation:

GNU Core Utils

words: 3 articles: 3
Non-POSIX only here.


words: 73 articles: 2
If you are a programmer, grep becomes a verb: "to grep" means "to search text files", much like "to Google" means "to search random stuff online".
This is a weak point of grep, it can't handle large lines that don't fit fully into memory:
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Getting started tutorial:

Standard streams

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words: 37 articles: 1
The OS that the Gods ordered be made.
One is reminded of Ulillillia, see also: The Story of Ulillillia by Atrocity Guide (2019)
We are all somewhere in the spectrum.
Video 2.
I like elephants and God likes elephants
. Source.

Executable file format

words: 8k articles: 38

Executable and Linkable Format

words: 8k articles: 37
For a quick and dirty introduction to the format, see: ELF Hello World Tutorial.

ELF Hello World Tutorial

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This section is present in another page, follow this link to view it.
Whenever Ciro Santilli learns about molecular biology, he can't help but to feel that it feels like programming, and notably systems programming and computer hardware design.
In some sense, the comparison is obvious: DNA is clearly a programmable medium like any assembly language, but still, systems programming did give Ciro some further feelings.
Ciro likes to think that maybe that is why a hardcore systems programmer like Bert Hubert got into molecular biology.
Some other people who mention similar things:


words: 227 articles: 8
Docker is good.
As a lightweight virtualization however, it does break more often than full proper virtualization like QEMU after some updates.
The images also appear to randomly update slightly and break things, even though you've specified e.g.:
FROM ubuntu:20.04
Also, we need more Linux distributions buildable from source, especially with Reproducible builds.


words: 180 articles: 6
One of the things Ciro Santilli really likes, see: Linux Kernel Module Cheat.
If computational physics simulates physics, emulators simulates computers.


words: 166 articles: 4
The leading open source cross architecture and KVM emulator of the 2010's.
Great way to understand how operating systems work, which Ciro Santilli used extensively in his Linux Kernel Module Cheat.
Ciro Santilli has some good related articles listed under: the best articles by Ciro Santillis.
User mode emulation refers to the ability of certain emulators to emulate userland code running on top of a specific operating system, usually Linux.
For example, QEMU allows you to run a variety of userland ELF programs directly on it, without an underlying Linux kernel running.
User mode emulation is achieved by implementing System calls and special filesystems such as /dev manually on the emulator one by one.
The general tradeoff is that simulation is less acurate as it may lack certain highly advanced kernel functionality you haven't implemented yet. But it is much easier to run executables with it, and you don't have to wait for boot to finish before running, you just run executables directly from the command line.
QEMU JavaScript port
words: 22 articles: 1
This is especially interesting for user mode emulation.
words: 16
Stopped 2019 apparently. Shame. We need something to be upstreamed!
Notable mentions:
Other notable people that are likely also awesome but Ciro has less familiarity with their contributions:

List of systems programmers

words: 555 articles: 6

Bert Hubert

words: 111
Co-founder of PowerDNS, an open source dNS implementation.
Homepage: says:
I sometimes contribute to science, I care a lot about Europe, innovation, biology & health
. All stuff Ciro cares about too! Cool dude! In particular Ciro loved his quote of I should have loved biology.
He's writing a fun-sounding book about molecular biology as of 2022: Appears to be closed source though. Ciro wonders if he really needs to sell the book for money after all those years though, rather than just publishing it online for free.
Looking at Bert just brings the Dutch Golden Age, and more in particular Antonie van Leeuwenhoek to mind. Epic.
Video 3.
How life is Digital by Bert Hubert (2021)
. Source. Just a "boring" overview of the central dogma of molecular biology ;-)
His standard C header seems to be as per example:
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.

Eli Benderski

words: 58
Amazing systems programming tutorials. Whenever you Google a hard topic, his blog comes up.
Also has many great contributions on Stack Overflow:
As of 2016, Eli worked at Google (reference). TODO before that, I had found his earlier info previously but lost it.
Eli focuses mostly on compiler toolchains, apparently with specific focus on
He also has some mathematics stuff, so cute:
Creator of QEMU and FFmpeg, both of which Ciro Santilli deeply respects. And a bunch other random stuff.
What is shocking about Fabrice this is that both are insanely important software that Ciro Santilli really likes, and both seem to be completely unrelated subjects!
Google made billions on top of this dude:
At last but not least, Fabrice also studied in the same school that Ciro studied in France, École Polytechnique.
It is a shame that he keeps such a low profile, there are no videos of him on the web, and he declines interviews.
Another surprising fact is that Fabrice has not worked for the "Big Tech Companies" as far as can be publicly seen, but rather mostly on smaller companies that he co-founded:
And he's also into some completely random projcts unsurprisingly:
Figure 2.
Fabrice Bellard in 2007
. Source. At a restaurant with the author apparently. Plus Miguel De Icaza who was in Paris for some conference, which they all presumably attended.
Creator of Mozilla rr, of which Ciro Santilli is a huge fan of!
He quit Mozilla in 2016 to try and commercialize an rr extension called Pernosco.
But as of 2022, he advertised himself as part of "Google Research", so maybe that went under, sample source: TODO when did he start? There's apparently an unrelated homonym:
He's apparently very religious, and very New Zelandish, auto-describes:
Christian. Repatriate Kiwi.
Terry A. Davis and D. Richard Hipp come to mind. One is tempted to speculate a correlation even, the proportion amongst systems programmers feels so much higher than in other areas of programming! Maybe it is because you have to be a God to do it in the first place.
Video 4.
Robert O'Callahan interview by Toby Ho (2022)
. Source.


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