Ciro Santilli
OurBigBook.comCiro Santilli's definition: softwareengineering.stackexchange.com/questions/151610/what-exactly-is-system-programming/399625#399625
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.
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.
Magic software that allows you to write a single program that runs on a wide range of hardware.
Tagged
Bibliography:
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.
Zephyr is cool. Its installation setup is annoying. But the project is cool.
Same behavior as micropython/blink_gpio.py.
zephyr/blink_gpio.c
#include <zephyr/kernel.h>
#include <zephyr/device.h>
#include <zephyr/drivers/gpio.h>
#define GPIO_PIN_NUM 0
int main(void)
{
const struct device *gpio_dev = DEVICE_DT_GET(DT_NODELABEL(gpio0));
if (!device_is_ready(gpio_dev)) {
return 1;
}
if (gpio_pin_configure(gpio_dev, GPIO_PIN_NUM, GPIO_OUTPUT | GPIO_ACTIVE_LOW) != 0) {
return 1;
}
while (1) {
gpio_pin_toggle(gpio_dev, GPIO_PIN_NUM);
k_sleep(K_MSEC(500));
}
return 0;
}
Blinks the on-board LED if the board has one.
Does not work on:
- Micro Bit: build fails
- Raspberry Pi Pico W: build works but does nothing because the LED is connected differently
Uses
printf to print some bytes somewhere, usually the first UART of the board.Real hardware is for newbs. Real hardware is for newbs.
Tested on Ubuntu 23.10 we approximately follow instructions from: docs.zephyrproject.org/3.4.0/develop/getting_started/index.html 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-pyelftools
python3 -m venv ~/zephyrproject/.venv
source ~/zephyrproject/.venv/bin/activate
pip install west
west init ~/zephyrproject
cd ~/zephyrproject
west update
west zephyr-export
cd ~
wget https://github.com/zephyrproject-rtos/sdk-ng/releases/download/v0.16.1/zephyr-sdk-0.16.1_linux-x86_64.tar.xz
tar xvf zephyr-sdk-0.16.1_linux-x86_64.tar.xz
cd zephyr-sdk-0.16.1
./setup.shThe 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:
~/zephyrproject/zephyrThe "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:and it outputs:The
cd ~/zephyrproject/zephyr
west build -b qemu_x86 samples/hello_world -t runHello World! qemu_x86qemu_x64 on the output comes from the CONFIG_BOARD macro github.com/zephyrproject-rtos/zephyr/blob/c15ff103001899ba0321b2c38013d1008584edc0/samples/hello_world/src/main.c#L11#include <zephyr/kernel.h>
int main(void)
{
printk("Hello World! %s\n", CONFIG_BOARD);
return 0;
}The
qemu_x86 board is documented at: docs.zephyrproject.org/3.4.0/boards/x86/qemu_x86/doc/index.htmlYou 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 runYou can also build and run separately with:
west build -b qemu_x86
west build -t runAnother important option is:But note that it does not modify your
west build -t menuconfigprj.conf automatically for you.Let's try on another target:and same output, but on a completely different board! The
rm -rf build
zephyr west build -b qemu_cortex_a53 -t runqemu_cortex_a53 board is documented at: docs.zephyrproject.org/3.4.0/boards/arm64/qemu_cortex_a53/doc/index.htmlThe list of all examples can be seen under:which for example contains:
ls ~/zephyrproject/zephyr/sampleszephyrproject/zephyr/samples/hello_worldSo run another sample simply select it, e.g. to run
zephyrproject/zephyr/samples/synchronization:west build -b qemu_cortex_a53 samples/synchronization -t runAs of 2025 and much earlier, there were only 3 operating systems that mattered on desktop:We refer to them as "the three operating systems".
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.
xkcd 619: Supported Features
. Source. This perfectly illustrates Linux development. First features that matter. Then useless features.Bill Gates vs Steve Jobs by Epic Rap Battles of History (2012)
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. Tagged
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!
- stackoverflow.com/questions/11408041/how-to-debug-the-linux-kernel-with-gdb-and-qemu/33203642#33203642 How to debug the Linux kernel with GDB and QEMU?
- cirosantilli.com/linux-kernel-module-cheat/gdb
Documents the Linux kernel. Somewhat of a competitor to Linux Kernel Module Cheat, but more wordy and less automated.
This is perhaps by far the most famous kernel driver book.
As of 2025 the latest version was quite old however, Linux Device Drivers book 3rd edition from 2005.
lwn.net/Kernel/LDD3/ contains the PDF of each chapter.
The book covers the Linux kernel version 2.6.10.
This repo has ported the kernels up to 5.10 as of writing. github.com/martinezjavier/ldd3/pull/86 attempts to go further into 6.x but has been ignored for two years unfortunately.
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.
No:
Tagged
Tagged
merlijn.sebrechts.be/blog/2020-08-02-why-one-snap-store/ has some very good comments on how
snap is more closed than Flatpak.Snap's permission system is extremely annoying, notably restricting access to home files. They need a popup that says "permission required by app, accept?" urgently!!!
- the best full featured free OS we have today, since POSIX gave up short of any UI specification, and Chrome OS is not there yet
- usable and likely efficient Java API for apps if Oracle doesn't manage to destroy it with its lawsuit
However, many, many, many terrible horrors come with it:
- it hasn't made the move to desktop for too many years. It could destroy Microsoft Windows and replace it with open source, but they just won't budge towards an unified mobile/desktop setup.
- vendors litter it with uninstallable bloatware that should be illegal. European Union to the rescue!!! www.cnbc.com/2020/12/15/digital-markets-act-eus-new-rules-on-big-tech.html
- vendors lock down devices so it is very hard to get sudo, let alone to modify their images!
- there isn't enough hardware standardization for open source distros to thrive like on desktop
- code drops mean that "master" is useless and trying to contribute from outside vendors' closed walls is a waste of time: stackoverflow.com/questions/1809774/how-to-compile-the-android-aosp-kernel-and-test-it-with-the-android-emulator/48310014#48310014
- if you ever go below the Java API, e.g. to C++ or AOSP build, everything is horrendous and undocumented
- Google doesn't care about the CLI, even the hello world requires creating infinite out-of-control boilerplate from a GUI: stackoverflow.com/questions/20801042/how-to-create-android-project-with-gradle-from-command-line/46994747#46994747
- the boot is uber bloated and takes forever in cycle simulators
The video folder is
DCIM/Camera.Respect. Big respect. Those people are hardcore from scratch hackers, and their wiki is amazing: wiki.archlinux.org/
It's just that Buildroot is more hardcore ;-)
But can you build the ISO full from source: Linux distribution buildable from source
The basis for Linux Kernel Module Cheat.
Buildroot is good.
This thing is sexy.
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.
On Ubuntu 23.10, a crash led to the creation of:After that simply running apport-cli as: led to the creation of: bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/2049368 a bug on the
/var/crash/_usr_bin_gnome-shell.1000.crashapport-cli gnome-shellgnome-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: bugs.launchpad.net/ubuntu/+source/gdm/+filebugThen, while reporting the bug, you want to give the developpers access to that Ubuntu's crash report system has already uploaded the
.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.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:and each of those contain a link to:which you yourself cannot see.
xdg-open https://errors.ubuntu.com/user/$(sudo cat /var/lib/whoopsie/whoopsie-id)https://errors.ubuntu.com/oops/<.uloaded error id>askubuntu.com/questions/434431/how-can-i-read-a-crash-file-from-var-crash asks how to read the
.crash files.Running:splits it up into a few files, but does not make any major improvements.
sudo apport-unpack /var/crash/_usr_sbin_gdm3.0.crash /tmp/appapport-retracesudo apt install apport-retrace
sudo chmod 666 /var/crash/_usr_sbin_gdm3.0.crash
apport-retrace -g /var/crash/_usr_sbin_gdm3.0.crashTried:but then
echo "deb http://ddebs.ubuntu.com $(lsb_release -cs) main restricted universe multiverse" | sudo tee -a /etc/apt/sources.list.d/ddebs.list
echo -e "deb http://ddebs.ubuntu.com $(lsb_release -cs)-updates main restricted universe multiverse\ndeb http://ddebs.ubuntu.com $(lsb_release -cs)-proposed main restricted universe multiverse" | sudo tee -a /etc/apt/sources.list.d/ddebs.list
sudo apt install ubuntu-dbgsym-keyringsudo apt update fails with:E: The repository 'http://ddebs.ubuntu.com impish-security Release' does not have a Release file.This section describes our attempts at compiling the Linux kernel for Ubuntu so as to use the exact patches and build configuration as used for a given Ubuntu release. The same toolchain would also be ideal, but perhaps this would require a Linux distribution buildable from source.
canonical-kteam-docs.readthedocs-hosted.com/en/public/how-to/build-kernel.html seems promising it says that for Ubuntu 24.04 and above you should do the following which was tested on Ubuntu 24.10:
sudo cp /etc/apt/sources.list /etc/apt/sources.list~
sudo sed -Ei 's/^# deb-src /deb-src /' /etc/apt/sources.list
sudo apt-get update
sudo apt build-dep -y linux linux-image-unsigned-$(uname -r)
sudo apt install -y fakeroot llvm libncurses-dev dwarves
apt source linux-image-unsigned-$(uname -r)
~/tmp/ubuntu/linux-6.11.0
cd linux-6.11.0
chmod a+x debian/rules
chmod a+x debian/scripts/*
chmod a+x debian/scripts/misc/*
fakeroot debian/rules clean
fakeroot debian/rules binaryThe build is extremely slow compared to a build of a more embedded and specifically targeted minimal kernel, and took about 2 hours on P14s. Their philosophy is likely to enable as many drivers as possible so that a single download will work for everyone. Which makes sense, fair enough. It would be cute though if there was a smarter way. Oh well.
After it finally finishes the build including our vmlinux is present at:
linux-6.11.0/debian/build/build-genericMore specialized versions:
- askubuntu.com/questions/1523535/installing-windows-11-in-a-vm-on-ubuntu-24-04 wants to keep real Windows data as well
- askubuntu.com/questions/1528367/what-is-the-best-way-to-set-up-a-windows-10-vm-with-hypervisor-and-virtual-machi asks for some hypervisor stuff
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_exprPossibly related:
- www.reddit.com/r/Ubuntu/comments/1ce1027/2404_is_a_terrible_release/
- bugs.launchpad.net/ubuntu/+source/nautilus/+bug/1795210
- bugs.launchpad.net/ubuntu/+source/nautilus/+bug/1823529
- askubuntu.com/questions/1406294/nautilus-keeps-crashing-in-22-04
- superuser.com/questions/42068/application-are-closed-down-unexpectedly-under-ubuntu
- ubuntuforums.org/showthread.php?t=2466502
- x.com/cirosantilli/status/1792792620323967227
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:It appears to be a bug in the AMDGPU open source driver.
[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 0x0000008000900Related 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.crashHappened 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: askubuntu.com/questions/7776/how-do-i-lock-the-desktop-screen-via-command-line
Bibliography:
- askubuntu.com/questions/1242110/after-upgrading-to-ubuntu-20-04-lockscreen-not-working canon
- askubuntu.com/questions/1246622/ubuntu-20-04-unable-to-lock-screen
- askubuntu.com/questions/1245071/cant-lock-screen-with-shortcut-on-ubuntu-20-04-gnome
- askubuntu.com/questions/1248756/super-l-not-working-on-ubuntu-20-04
Switching to the other installed kernel, 5.9 made boot work.
The solution on kernel 6.2 was:as per comments under: bugs.launchpad.net/ubuntu/+source/linux/+bug/2012559. This also made the nvidia driver work: Find GPU information in Ubuntu.
sudo apt instal nvidia-driver-515Previously I had:and it blew up before reaching disk decryption.
nvidia-driver-510I also tried:but that broke in a different way:
nvidia-driver-525Finished 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:
Happening multiple times a day on Ubuntu 22.04 for Chromium, even though I turn computer on and off daily, unbearable:
- askubuntu.com/questions/1412575/pending-update-of-snap-store
- askubuntu.com/questions/1412140/pending-update-of-firefox-snap-close-the-app-to-avoid-disruptions
- forum.snapcraft.io/t/how-to-disable-snapd-update-notifications-permanently/31117 Settings > Notifications > Snapd User Session Agent
- www.reddit.com/r/Ubuntu/comments/v1s919/disable_pending_update_of_snap_message_kiosk/
- forum.snapcraft.io/t/refresh-app-awareness-call-for-testing/29123
GDM crashes sometimes when switching windows right after opening a new window: bugs.launchpad.net/ubuntu/+source/gdm/+bug/1956299
Please refer to Video "Linus Torvalds saying "Nvidia Fuck You" (2012)".
Does not happen every time, only some times. Can't figure out why. Usually happens when has suspended for a longer time.
bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers-470/+bug/1946303 sounds like a likely report, Nvidia driver version 470, but can't find those error messages anywhere. The last line of:once was:which is when sleep starts.
journalctl -o short-precise -k -b -1PM: suspend entry (deep)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 exitbugs.launchpad.net/ubuntu/+source/linux/+bug/1949977 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:had the following interesting lines:and there was a corresponding
journalctl -o short-precise -k -b -1nvidia-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/var/crash/_usr_sbin_gdm3.0.crash.Related "GPU has fallen off the bus": askubuntu.com/questions/868321/gpu-has-fallen-off-the-bus-nvidia
Sometimes it just feels like Ubuntu devs don't actually use Ubuntu as a desktop.
Some extremely annoying 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: askubuntu.com/questions/1293685/out-of-space-on-boot-zpool-and-cant-run-updates-anymore/1374204#1374204
And then this to disable automatic snapshots in the future: askubuntu.com/questions/1233049/disable-automatic-zsys-snapshots-zfs-on-root/1279593#1279593
sudo mv /etc/apt/apt.conf.d/90_zsys_system_autosnapshot /etc/apt/apt.conf.d/90_zsys_system_autosnapshot.disabledGod, 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.
Issues:
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?
The OS that the Gods ordered be made.
One is reminded of Ulillillia, see also: www.youtube.com/watch?v=9-79yOZ13qg The Story of Ulillillia by Atrocity Guide (2019)
We are all somewhere in the spectrum.
The real explanation: stackoverflow.com/questions/1780599/what-is-the-meaning-of-posix/31865755#31865755
Tagged
Overview by Ciro Santilli at: superuser.com/questions/284342/what-are-path-and-other-environment-variables-and-how-can-i-set-or-use-them/1864687#1864687
This section is about POSIX environment variable that have special effects.
They are documented by POSIX at: pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08
Some mentions by Ciro Santilli at: superuser.com/questions/284342/what-are-path-and-other-environment-variables-and-how-can-i-set-or-use-them/1864687#1864687
Non-POSIX only here.
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:
- superuser.com/questions/1703029/is-there-a-limit-for-a-line-length-for-grep-command-to-process-correctly what is the grep line limit?
- unix.stackexchange.com/questions/223078/best-way-to-grep-big-binary-file/758528#758528 Ciro's
bgrepcanon - large not required but mentioning bgrep anyways:
- superuser.com/questions/1368263/use-grep-for-a-long-line-to-get-the-part-of-the-line/1811969#1811969
- unix.stackexchange.com/questions/217936/equivalent-command-to-grep-binary-files/758544#758544
- stackoverflow.com/questions/2034799/how-to-truncate-long-matching-lines-returned-by-grep-or-ack/77263826#77263826
- stackoverflow.com/questions/9988379/how-to-grep-a-text-file-which-contains-some-binary-data leaving this one alone for now
- stackoverflow.com/questions/65674717/how-to-check-if-a-binary-file-is-contained-inside-another-binary-from-the-linux search pattern from file
Getting started tutorial: unix.stackexchange.com/questions/223078/best-way-to-grep-a-big-binary-file/758528#758528
For a quick and dirty introduction to the format, see: ELF Hello World Tutorial.
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.
- The most important analogy perhaps is observability, or more precisely the lack of it. For the computer, this is described at: The lower level you go into a computer, the harder it is to observe things.And then, when Ciro started learning a bit about biology techniques, he started to feel the exact same thing.For example when he played with E. Coli Whole Cell Model by Covert Lab, the main thing Ciro felt was: it is going to be hard to verify any of this data, because it is hard/impossible to know the concentration of each element in a cell as a function of time.More generally of course, this is exactly why making any biology discovery is so hard: we can't easily see what's going on inside the cell, and have to resort to indirect ways of doing so..This exact idea was highlighted by I should have loved biology by James Somers:
For a computer scientist, a biologist's methods can seem insane; the trouble comes from the fact that cells are too small, too numerous, too complex to analyze the way a programmer would, say in a step-by-step debugger.
And then just like in software, some of the methods biologists use to overcome the lack of visibility have direct software analogues:- add instrumentation to cells, e.g. GFP tagging comes to mind
- emulation, e.g. E. Coli Whole Cell Model by Covert Lab
- The boot process is another one. E.g. in x86 the way that you start in 16-bit mode, largely compatible into the 70's, then move to 32-bit and finally 64, does feel a lot the way a earlier stages of embryo development looks more and more like more ancient animals.
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:
- I should have loved biology by James Somers highlights the computer abstraction layer analogy between the two:
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:20.04Also, we need more Linux distributions buildable from source, especially with Reproducible builds.
One of the things Ciro Santilli really likes, see: Linux Kernel Module Cheat.
If computational physics simulates physics, emulators simulates computers.
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: Section "The best articles by Ciro Santilli".
Tagged
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.
This is especially interesting for user mode emulation.
Stopped 2019 apparently. Shame. We need something to be upstreamed!
- source code: github.com/atrosinenko/qemujs
- demo: atrosinenko.github.io/qemujs-demo/
- demo source code: github.com/atrosinenko/qemujs-demo
This is a cool project that attempts to make it easy to emulate any of the three operating systems on QEMU.
Homepage: github.com/quickemu-project/quickemu
Introductor tutorial by Ciro Santilli: askubuntu.com/questions/884534/how-to-run-ubuntu-desktop-on-qemu/1545712#1545712 intro
Unofrtunately as of 2025 the project was falling a bit back on support, and the latest versions of the two closed source systems were buggy, tested as of quickemu 4.9.7 on Ubuntu 25.04:
- Windows 11: github.com/quickemu-project/quickemu/issues/1475
- MacOS 14 (Sonoma) installs MacOS 15, which is not listed on the list of installable systems: github.com/quickemu-project/quickemu/issues/1561. The issue was closed, but it still happens.
This would serve as a good workaround for the lack of clipboard and the default annoyiance of mouse capture!
I don't see how to get it working out of box immediately, but after you do on guest:then the host terminal tells you the ssh command e.g.:and that worked. You can also quickemu with:to not get any annoying GUI.
sudo apt install openssh-serverssh user@localhost -p 22220quickemu --display noneNotable mentions:
- Tom Tromey from Red Hat: www.youtube.com/watch?v=RwDA3oIOtWw Dude's a GDB God! He might be gay from that talk.
Other notable people that are likely also awesome but Ciro has less familiarity with their contributions:
- Dwayne Richard Hipp from SQLite
- Daniel Stenberg from cURL
- Michael Niedermayer also from FFmpeg. ikaruga.co.uk/~snacky/mn.html highlights his brutal directness and efficiency, and sometimes sense of humour
Co-founder of PowerDNS, an open source dNS implementation.
Homepage: berthub.eu/ says:.
All stuff Ciro cares about too! Cool dude! In particular Ciro loved his quote of I should have loved biology.
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: berthub.eu/dna-book. 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.
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: www.sqlite.org/src/file/ext/misc/rot13.c
** 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.Homepage: eli.thegreenplace.net/
Amazing systems programming tutorials. Whenever you Google a hard topic, his blog comes up.
Also has many great contributions on Stack Overflow: stackoverflow.com/users/8206/eli-bendersky
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.
He also has some mathematics stuff, so cute: eli.thegreenplace.net/2015/change-of-basis-in-linear-algebra/
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:
- FFmpeg is the backend of YouTube
- QEMU is the default emulator for Android Studio as of 2019, which Android developers use by default under the hood to develop Android Apps on their desktop without the need for a real device.
At last but not least, Fabrice also studied in the same school that Ciro Santilli 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: www.quora.com/Computer-Programmers/Computer-Programmers-Where-is-Fabrice-Bellard-employed
And he's also into some completely random projcts unsurprisingly:
- www.computerhistory.org/tdih/january/6/ Computer Scientist Fabrice Bellard Announces Computing Pi to Record Number of Digits
Bibliography:
- smartbear.com/de/blog/2011/fabrice-bellard-portrait-of-a-super-productive-pro/ contains a list of his projects as of 2011
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: archive.ph/o9622. TODO when did he start? There's apparently an unrelated homonym: www.linkedin.com/in/rob-ocallahan/
He's apparently very religious, and very New Zelandish, twitter.com/rocallahan auto-describes: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.
Christian. Repatriate Kiwi.