Many people that were once enthusiast Twitter users have dropped as a
direct or indirect effect of its ownership change and the following policy
changes. Given Twitter X is getting each time more irrelevant, it is
less interesting and enciting for more and more people… But also, its
current core users (mostly, hate-apologists of the right-wing mindset that
finds conspiration theories everywhere) are becoming more commonplace, and
by sheer probability (if not for algorithmic bias), every time it becomes
more likely a given piece of content will be linked to what their authors
would classify as crap.
So, there has been in effect an X exodus. This has been reported in media
outlets as important as Reuters, or The
Guardianresearch
institutes such as
Berkeley,
even media that no matter how hard you push cannot be identified as the
radical left Mr. Trump is so happy to blame for everything, such as
Forbes…
Today I read a short note in a magazine I very much enjoy, Communications
of the ACM, where SIGDOC (the ACM’s Special Interest
Group on Design of Communication) is officially closing their X
account. The reasoning is crystal clear. They have the mission to create
and study User Experience (UX) implementations and report on it, «focused
on making communication clearer and more human centered». That is no
longer, for many reasons, a goal that can be furthered by the means of an X
account.
(BTW, and… How many people are actually angry that Mr. Musk took the X11
old logo and made it his? I am sure it is now protected under too many
layers of legalese, even though I am aware of it since at least 30 years
ago…)
Here, in classic Goerzen deep dive fashion, is more information than you knew you wanted about a topic you’ve probably never thought of. I found it pretty interesting, because it took me down a rabbit hole of subsystems I’ve never worked with much and a mishmash of 1980s and 2020s tech.
I had previously tried and failed to get an actual 80x25 Linux console, but I’ve since figured it out!
This post is about the Linux text console – not X or Wayland. We’re going to get the console right without using those systems. These instructions are for Debian trixie, but should be broadly applicable elsewhere also. The end result can look like this:
(That’s a Wifi Retromodem that I got at VCFMW last year in the Hayes modem case)
What’s a pixel?
How would you define a “pixel” these days? Probably something like “a uniquely-addressable square dot in a two-dimensional grid”.
In the world of VGA and CRTs, that was just a logical abstraction. We got an API centered around that because it was convenient. But, down the VGA cable and on the device, that’s not what a pixel was.
A pixel, back then, was a time interval. On a multisync monitor, which were common except in the very early days of VGA, the timings could be adjusted which produced logical pixels of different sizes. Those screens often had a maximum resolution but not necessarily a “native resolution” in the sense that an LCD panel does. Different timings produced different-sized pixels with equal clarity (or, on cheaper monitors, equal fuzziness).
A side effect of this was that pixels need not be square. And, in fact, in the standard DOS VGA 80x25 text mode, they weren’t.
You might be seeing why DVI, DisplayPort, and HDMI replaced VGA for LCD monitors: with a VGA cable, you did a pixel-to-analog-timings conversion, then the display did a timings-to-pixels conversion, and this process could be a bit lossy. (Hence why you sometimes needed to fill the screen with an image and push the “center” button on those older LCD screens)
(Note to the pedantically-inclined: yes I am aware that I have simplified several things here; for instance, a color LCD pixel is made up of approximately 3 sub-dots of varying colors, and that things like color eInk displays have two pixel grids with different sizes of pixels layered atop each other, and printers are another confusing thing altogether, and and and…. MOST PEOPLE THINK OF A PIXEL AS A DOT THESE DAYS, OK?)
What was DOS text mode?
We think of this as the “standard” display: 80 columns wide and 25 rows tall. 80x25. By the time Linux came along, the standard Linux console was VGA text mode – something like the 4th incarnation of text modes on PCs (after CGA, MDA, and EGA). VGA also supported certain other sizes of characters giving certain other text dimensions, but if I cover all of those, this will explode into a ridiculously more massive page than it already is.
So to display text on an 80x25 DOS VGA system, ultimately characters and attributes were written into the text buffer in memory. The VGA system then rendered it to the display as a 720x400 image (at 70Hz) with non-square pixels such that the result was approximately a 4:3 aspect ratio.
The font used for this rendering was a bitmapped one using 8x16 cells. You might do some math here and point out that 8 * 80 is only 640, and you’d be correct. The fonts were 8x16 but the rendered cells were 9x16. The extra pixel was normally used for spacing between characters. However, in line graphics mode, characters 0xC0 through 0xDF repeated the 8th column in the position of the 9th, allowing the continuous line-drawing characters we’re used to from TUIs.
Problems rendering DOS fonts on modern systems
By now, you’re probably seeing some of the issues we have rendering DOS screens on more modern systems. These aren’t new at all; I remember some of these from back in the days when I ran OS/2, and I think also saw them on various terminals and consoles in OS/2 and Windows.
Some issues you’d encounter would be:
Incorrect aspect ratio caused by using the original font and rendering it using 1:1 square pixels (resulting in a squashed appearance)
Incorrect aspect ratio for ANOTHER reason, caused by failing to render column 9, resulting in text that is overall too narrow
Characters appearing to be touching each other when they shouldn’t (failing to render column 9; looking at you, dosbox)
Gaps between line drawing characters that should be continuous, caused by rendering column 9 as empty space in all cases
Character set issues
DOS was around long before Unicode was. In the DOS world, there were codepages that selected the glyphs for roughly the high half of the 256 possible characters. CP437 was the standard for the USA; others existed for other locations that needed different characters. On Unix, the USA pre-Unicode standard was Latin-1. Same concept, but with different character mappings.
Nowadays, just about everything is based on UTF-8. So, we need some way to map our CP437 glyphs into Unicode space. If we are displaying DOS-based content, we’ll also need a way to map CP437 characters to Unicode for display later, and we need these maps to match so that everything comes out right. Whew.
So, let’s get on with setting this up!
Selecting the proper video mode
As explained in my previous post, proper hardware support for DOS text mode is limited to x86 machines that do not use UEFI. Non-x86 machines, or x86 machines with UEFI, simply do not contain the necessary support for it. As these are now standard, most of the time, the text console you see on Linux is actually the kernel driving the video hardware in graphics mode, and doing the text rendering in software.
That’s all well and good, but it makes it quite difficult to actually get an 80x25 console.
First, we need to be running at 720x400. This is where I ran into difficulty last time. I realized that my laptop’s LCD didn’t advertise any video modes other than its own native resolution. However, almost all external monitors will, and 720x400@70 is a standard VGA mode from way back, so it should be well-supported.
You need to find the Linux device name for your device. You can look at the possible devices with ls -l /sys/class/drm. If you also have a GUI, xrandr may help too. But in any case, each directory under /sys/class/drm has a file named modes, and if you cat them all, you will eventually come across one with a bunch of modes defined. Drop the leading “card0” or whatever from the directory name, and that’s your device. (Verify that 720x400 is in modes while you’re at it.)
Now, you’re going to edit /etc/default/grub and add something like this to GRUB_CMDLINE_LINUX_DEFAULT:
video=DP-1:720x400@70
Of course, replace DP-1 with whatever your device is.
Now you can run update-grub and reboot. You should have a 720x400 display.
At first, I thought I had succeeded by using Linux’s built-in VGA font with that mode. But it looked too tall. After noticing that repeated 0s were touching, I got suspicious about the missing 9th column in the cells. stty -a showed that my screen was 90x25, which is exactly what it would show if I was using 8x16 instead of 9x16 cells. Sooo…. I need to prepare a 9x16 font.
Preparing a font
Here’s where it gets complicated.
I’ll give you the simple version and the hard mode.
The file we’re interested in is otb - Bm (linux bitmap)/Bm437_IBM_VGA_9x16.otb. Open it in fontforge by running fontforge BmPlus_IBM_VGA_9x16.otb. When it asks if you will load the bitmap fonts, hit select all, then yes. Go to File -> generate fonts. Save in a BDF, no need for outlines, and use “guess” for resolution.
Now you have a file such as Bm437_IBM_VGA_9x16-16.bdf. Excellent.
Now we need to generate a Unicode map file. We will make sure this matches the system’s by enumerating every character from 0x00 to 0xFF, converting it from CP437 to Unicode, and writing the appropriate map.
By convention, we normally store these files gzipped, so gzip CP437-VGA.psf.
You can test it on the console with setfont CP437-VGA.psf.gz.
Now copy this file into /usr/local/etc.
Activating the font
Now, edit /etc/default/console-setup. It should look like this:
# CONFIGURATION FILE FOR SETUPCON
# Consult the console-setup(5) manual page.
ACTIVE_CONSOLES="/dev/tty[1-6]"
CHARMAP="UTF-8"
CODESET="Lat15"
FONTFACE="VGA"
FONTSIZE="8x16"
FONT=/usr/local/etc/CP437-VGA.psf.gz
VIDEOMODE=
# The following is an example how to use a braille font
# FONT='lat9w-08.psf.gz brl-8x8.psf'
At this point, you should be able to reboot. You should have a proper 80x25 display! Log in and run stty -a to verify it is indeed 80x25.
Using and testing CP437
Part of the point of CP437 is to be able to access BBSs, ANSI art, and similar.
Now, remember, the Linux console is still in UTF-8 mode, so we have to translate CP437 to UTF-8, then let our font map translate it back to CP437. A weird trip, but it works.
Let’s test it using the Textfiles ANSI art collection. In the artworks section, I randomly grabbed a file near the top: borgman.ans. Download that, and display with:
clear; iconv -f CP437 -t UTF-8 < borgman.ans
You should see something similar to – but actually more accurate than – the textfiles PNG rendering of it, which you’ll note has an incorrect aspect ratio and some rendering issues. I spot-checked with a few others and they seemed to look good. belinda.ans in particular tries quite a few characters and should give you a good sense if it is working.
Use with interactive programs
That’s all well and good, but you’re probably going to want to actually use this with some interactive program that expects CP437. Maybe Minicom, Kermit, or even just telnet?
For this, you’ll want to apt-get install luit. luit maps CP437 (or any other encoding) to UTF-8 for display, and then of course the Linux console maps UTF-8 back to the CP437 font.
Here’s a way you can repeat the earlier experiment using luit to run the cat program:
clear; luit -encoding CP437 cat borgman.ans
You can run any command under luit. You can even run luit -encoding CP437 bash if you like. If you do this, it is probably a good idea to follow my instructions on generating locales on my post on serial terminals, and then within luit, set LANG=en_us.IBM437. But note especially that you can run programs like minicom and others for accessing BBSs under luit.
Final words
This gave you a nice DOS-type console. Although it doesn’t have glyphs for many codepoints, it does run in UTF-8 mode and therefore is compatible with modern software.
You can achieve greater compatibility with more UTF-8 codepoints with the DOS font, at the expense of accuracy of character rendering (especially for the double-line drawing characters) by using /usr/share/bdf2psf/standard.equivalents instead of /dev/null in the bdf2psf command.
Or you could go for another challenge, such as using the DEC vt-series fonts for coverage of ISO-8859-1. But just using fonts extracted from DEC ROM won’t work properly, because DEC terminals had even more strangeness going on than DOS fonts.
Six years ago, I was inspired to buy a DEC serial terminal. Since then, my collection has grown to include several DEC models, an IBM 3151, a Wyse WY-55, a Televideo 990, and a few others.
When you are running a terminal program on Linux or MacOS, what you are really running is a terminal emulator. In almost all cases, the terminal emulator is emulating one of the DEC terminals in the vt100 through vt520 line, which themselves use a command set based on an ANSI standard.
In short, you spend all day using a program designed to pretend to be the exact kind of physical machine I’m using for this experiment!
While I have used a terminal with the Pi, I’ve never before used it as a serial console all the way from early boot, and I have never installed Debian using the terminal to run the installer. A serial terminal gives you a login prompt. A serial console gives you access to kernel messages, the initrd environment, and sometimes even the bootloader.
This might be fun, I thought.
I selected one of my vt510 terminals for this. It is one of my newer ones, having been built in 1993. But it has a key feature: I can remap Ctrl to be at the caps lock position, something I do on every other system I use anyhow. I could have easily selected an older one from the 1980s.
Kernel configuration
To enable a serial console for Linux, you need to pass a parameter on the kernel command line. See the kernel documentaiton for more. I very frequently see instructions that are incomplete; they particularly omit flow control, which is most definitely needed for these real serial terminals.
I run my terminal at 57600 bps, so the parameter I need is console=ttyS0,57600n8r. The “r” means to use hardware flow control (ttyS0 corresponds to the first serial port on the system; use ttyS1 or something else as appropriate for your situation). While booting the Debian installer, according to Debian’s instructions, it may be useful to also add TERM=vt102 (the installer doesn’t support the vt510 terminal type directly). The TERM parameter should not be specified on a running system after instlalation.
Booting the Debian installer
When you start the Debian installer, to get it into serial mode, you have a couple of options:
You can use a traditional display and keyboard just long enough to input the kernel parameters described above
You can edit the bootloader configuration on the installer’s filesystem prior to booting from it
Option 1 is pretty easy. Option 2 is hard mode, but not that bad.
On x86, the Debian installer boots in at least two different ways: it uses GRUB if you’re booting under UEFI (which is most systems these days), or ISOLINUX if you are booting from the BIOS.
If using GRUB, the file to edit on the installer image is boot/grub/grub.cfg.
Near the top, add these lines:
serial --unit=0 --speed=57600 --word=8 --parity=no --stop=1
terminal_input console serial
terminal_output console serial
Unit 0 corresponds to ttyS0 as above.
GRUB’s serial command does not support flow control. If your terminal gets corrupted during the GRUB stage, you may need to configure it to a slower speed.
Then, find the “linux” line under the “Install” menuentry. Edit it to insert console=ttyS0,57600n8r TERM=vt102 right after the vga=788.
Save, unmount, and boot. You should see the GRUB screen displayed on your serial terminal. Select the Install option and the installer begins.
If you are using BIOS boot, I’m sure you can do something similar with the files in the isolinux directory, but haven’t researched it.
Now, you can install Debian like usual!
Configuring the System
I was pleasantly surprised to find that Debian’s installer took care of many, but not all, of the things I want to do in order to make the system work nicely with a serial terminal. You can perform these steps from a chroot under the installer environment before a reboot, or later in the running system.
First, while Debian does set up a getty (the program that displays the login prompt) on the serial console by default, it doesn’t enable hardware flow control. So let’s do that.
Configuring the System: agetty with systemd
Run systemctl edit serial-getty@ttyS0.service. This opens an editor that lets you customize the systemd configuration for a given service without having to edit the file directly. All you really need to do is modify the agetty command, so we just override it. At the top, in the designated area, write:
The empty ExecStart= line is necessary to tell systemd to remove the existing ExecStart command (otherwise, it will logically contain two ExecStart lines, which is an error).
These arguments say:
–wait-cr means to wait for the user to press Return at the terminal before attempting to display the login prompt
-8 tells it to assume 8-bit mode on the serial line
-h enables hardware flow control
-L=always enables local line mode, disabling monitoring of modem control lines
%I substitutes the name of the port from systemd
57600 gives the desired speed, and vt510 gives the desired setting for the TERM environment variable
The systemd documentation refers to this page about serial consoles, which gives more background. However, I think it is better to use the systemctl edit method described here, rather than just copying the config file, since this lets things like new configurations with new Debian versions take effect.
Configuring the System: Kernel and GRUB
Your next stop is the /etc/default/grub file. Debian’s installer automatically makes some changes here. There are three lines you want to change. First, near the top, edit GRUB_CMDLINE_LINUX_DEFAULT and add console=tty0 console=ttyS0,57600n8r. By specifying console twice, you allow output to go both to the standard display and to the serial console. By specifying the serial console last, you make it be the preferred one for things like entering the root filesystem password.
Next, towards the bottom, make sure these two lines look like this:
Finally, near the top, you may want to raise the GRUB_TIMEOUT to somewhere around 10 to 20 seconds since things may be a bit slower than you’re used to.
Save the file and run update-grub.
Now, GRUB will display on both your standard display and the serial console. You can edit the boot command from either. If you have a VGA or HDMI monitor attached, for instance, and need to not use the serial console, you can just edit the Linux command line in GRUB and remove the reference to ttyS0 for one boot. Easy!
That’s it. You now have a system that is fully operational from a serial terminal.
My original article from 2019 has some additional hints, including on how to convert from UTF-8 for these terminals.
Update 2025-09-17: It is also useful to set up proper locales. To do this, first edit /etc/locale.gen. Make sure to add, or uncomment:
Then run locale-gen. Normally, your LANG will be set to en_us.UTF-8, which will select the appropriate encoding. Plain en_US will select ISO-8859-1, which you need for the vt510. Then, add something like this to your ~/.bashrc:
if [ `tty` = "/dev/ttyS0" -o "$TERM" = "vt510" ]; then
stty -iutf8
# might add ixon ixoff
export LANG=en_US
export MANOPT="-E ascii"
stty rows 25
fi
if [ "$TERM" = "screen" -o "$TERM" = "vt100" ]; then
export LANG=en_US.utf8
fi
Finally, in my ~/.screenrc, I have this. It lets screen convert between UTF-8 and ISO-8859-1:
I sometimes use Vagrant to deploy my VM&aposs and recently when I tried to deploy one for Trixie, I could see one available. So I checked the official Debian images on Vagrant cloud at https://portal.cloud.hashicorp.com/vagrant/discover/debian and could not find an image for trixie on Vagrant cloud.
Also looked at other cloud image sources like Docker hub, and I could see an image their for Trixie. So I looked into how I can generate a Vagrant image locally for Debian to use.
this will install some dependency packages, will ask for sudo password if need to install something not already installed.
Let&aposs call make help
$ make help
To run this makefile, run:
make <DIST>-<CLOUD>-<ARCH>
WHERE <DIST> is bullseye, buster, stretch, sid or testing
And <CLOUD> is azure, ec2, gce, generic, genericcloud, nocloud, vagrant, vagrantcontrib
And <ARCH> is amd64, arm64, ppc64el
Set DESTDIR= to write images to given directory.
$ make trixie-vagrant-amd64
umask 022; \
./bin/debian-cloud-images build \
trixie vagrant amd64 \
--build-id vagrant-cloud-images-master \
--build-type official
usage: debian-cloud-images build
debian-cloud-images build: error: argument RELEASE: invalid value: trixie
make: *** [Makefile:22: trixie-vagrant-amd64] Error 2
As you can see, trixie is not even in the available options and it is not building as well. Before trying to look at updating the codebase, I looked at the pending MR&aposs on Salsa and found Michael Ablassmeier&aposs pending merge request at https://salsa.debian.org/cloud-team/debian-vagrant-images/-/merge_requests/18
So let me test that commit and see if I can build trixie locally from Michael&aposs MR
$ make help
To run this makefile, run:
make <DIST>-<CLOUD>-<ARCH>
WHERE <DIST> is bullseye, buster, stretch, sid or testing
And <CLOUD> is azure, ec2, gce, generic, genericcloud, nocloud, vagrant, vagrantcontrib
And <ARCH> is amd64, arm64, ppc64el
Set DESTDIR= to write images to given directory.
$ make trixie-vagrant-amd64
umask 022; \
./bin/debian-cloud-images build \
trixie vagrant amd64 \
--build-id vagrant-cloud-images-master \
--build-type official
2025-09-17 00:36:25,919 INFO Adding class DEBIAN
2025-09-17 00:36:25,919 INFO Adding class CLOUD
2025-09-17 00:36:25,919 INFO Adding class TRIXIE
2025-09-17 00:36:25,920 INFO Adding class VAGRANT
2025-09-17 00:36:25,920 INFO Adding class AMD64
2025-09-17 00:36:25,920 INFO Adding class LINUX_IMAGE_BASE
2025-09-17 00:36:25,920 INFO Adding class GRUB_PC
2025-09-17 00:36:25,920 INFO Adding class LAST
2025-09-17 00:36:25,921 INFO Running FAI: sudo env PYTHONPATH=/home/rajudev/dev/salsa/michael/debian-vagrant-images/src/debian_cloud_images/build/../.. CLOUD_BUILD_DATA=/home/rajudev/dev/salsa/michael/debian-vagrant-images/src/debian_cloud_images/data CLOUD_BUILD_INFO={"type": "official", "release": "trixie", "release_id": "13", "release_baseid": "13", "vendor": "vagrant", "arch": "amd64", "build_id": "vagrant-cloud-images-master", "version": "20250917-1"} CLOUD_BUILD_NAME=debian-trixie-vagrant-amd64-official-20250917-1 CLOUD_BUILD_OUTPUT_DIR=/home/rajudev/dev/salsa/michael/debian-vagrant-images CLOUD_RELEASE_ID=vagrant CLOUD_RELEASE_VERSION=20250917-1 fai-diskimage --verbose --hostname debian --class DEBIAN,CLOUD,TRIXIE,VAGRANT,AMD64,LINUX_IMAGE_BASE,GRUB_PC,LAST --size 100G --cspace /home/rajudev/dev/salsa/michael/debian-vagrant-images/src/debian_cloud_images/build/fai_config debian-trixie-vagrant-amd64-official-20250917-1.raw
..... continued
Although we can now build the images, we just don&apost see an option for it in the help text, not even for bookworm. Just the text in Makefile is outdated, but I can build and trixie Vagrant box now. Thanks to Michael for the fix.
Update 2025-09-18: I figured out how to do this, at least for many non-laptop screens. This post still contains a lot of good background detail, however.
Somehow along the way, a feature that I’ve had across DOS, OS/2, FreeBSD, and Linux — and has been present on PCs for more than 40 years — is gone.
That feature, of course, is the 80×25 text console.
Linux has, for awhile now, rendered its text console using graphic modes. You can read all about it here. This has been necessary because only PCs really had the 80×25 text mode (Raspberry Pis, for instance, never did), and even they don’t have it when booted with UEFI.
I’ve lately been annoyed that:
The console is a different size on every screen — both in terms of size of letters and the dimensions of it
If a given machine has more than one display, one or both of them will have parts of the console chopped off
My system seems to run with three different resolutions or fonts at different points of the boot process. One during the initrd, and two different ones during the remaining boot.
And, I wanted to run some software on the console that was designed with 80×25 in mind. And I’d like to be able to plug in an old VGA monitor and have it just work if I want to do that.
That shouldn’t be so hard, right? Well, the old vga= option that you are used to doesn’t work when you booted from UEFI or on non-x86 platforms. Most of the tricks you see online for changing resolutions, etc., are no longer relevant. And things like setting a resolution with GRUB are useless for systems that don’t use GRUB (including ARM).
VGA text mode uses 8×16 glyphs in 9×16 cells, where the pixels are non-square, giving a native resolution of 720×400 (which historically ran at 70Hz), which should have streched pixels to make a 4:3 image.
While it is possible to select a console font, and 8×16 fonts are present and supported in Linux, it appears to be impossible to have a standard way to set 720×400 so that they present in a reasonable size, at the correct aspect ratio, with 80×25.
Tricks like nomodeset no longer work on UEFI or ARM systems. It’s possible that kmscon or something like it may help, but I’m not even certain of that (video=eDP1:720×400 produced an error saying that 720×400 wasn’t a supported mode, so I’m unsure kmscon would be any better.) Not that it matters; all the kmscon options to select a font or zoom are broken, and it doesn’t offer mode selection anyhow.
I think I’m going to have to track down an old machine.
If you use HaProxy to e.g. terminate TLS on the frontend and connect via
TLS to a backend, one has to take care of sending the SNI (server name
indication) extension in the TLS handshake sort of manually.
Even if you use host names to address the backend server, e.g.
server foobar foobar.example:2342 ssl verify required ca-file /etc/haproxy/ca/foo.crt
HaProxy will
try to establish the connection without SNI. You manually have to enforce
SNI here, e.g.
server foobar foobar.example:2342 ssl verify required ca-file /etc/haproxy/ca/foo.crt sni str(foobar.example)
The surprising thing here was that it requires an expression, so you can not just write sni foobar.example, you've to wrap it in an expression. The simplest one is making sure it's a string.
Update: Might be noteworthy that you've to configure SNI for the health check separately, and
in that case it's a string not an expression. E.g.
If someone hands you an IP:Port of a Google Cloud load balancer, and tells you to
connect there with TLS, but all you receive in return is an F (and a few other
bytes with none printable characters) on running openssl s_client -connect ...,
you might be missing SNI (server name indication). Sadly the other side
was not transparent enough to explain in detail which exact type of Google Cloud
load balancer they used, but the conversation got more detailed and up to a working
TLS connection when the missing -servername foobar.host.name was added. I could not
find any sort of official documentation on the responses of the GFE (the frontend part)
when TLS parameters do not match the expectations. Also you won't have anything in the
logs, because logging at Google Cloud is a backend function, and as long as your requests
do not reach the backend, there are no logs. That makes it rather unpleasant to debug such cases,
when one end says "I do not see anything in the logs", and the other one says "you reject
my connection and just reply F".
We announced tag2upload’s open beta in mid-July. That was in the middle of the the freeze for trixie, so usage was fairly light until the forky floodgates opened.
Since then the service has successfully performed 637 uploads, of which 420 were in the last 32 days. That’s an average of about 13 per day. For comparison, during the first half of September up to today there have been 2475 uploads to unstable. That’s about 176/day.
So, tag2upload is already handling around 7.5% of uploads. This is very gratifying for a service which is advertised as still being in beta!
Sean and I are very pleased both with the uptake, and with the way the system has been performing.
During this open beta period we have been hard at work. We have made many improvements to the user experience.
Current git-debpush in forky, or trixie-backports, is much better at detecting various problems ahead of time.
When uploads do fail on the service the emailed error reports are now more informative. For example, anomalies involving orig tarballs, which by definition can’t be detected locally (since one point of tag2upload is not to have tarballs locally) now generally result in failure reports containing a diffstat, and instructions for a local repro.
The biggest of these is that the service should be able to retry when Salsa fails. Sadly, Salsa isn’t wholly reliable, and right now if it breaks when the service is trying to handle your tag, your upload can fail.
We think most of these failures could be avoided. Implementing retries is a fairly substantial task, but doesn’t pose any fundamental difficulties. We’re working on this right now.
We want to support pristine-tar, so that pristine-tar users can do a new upstream release. Andrea Pappacoda is working on that with us. See #1106071. (Note that we would generally recommend against use of pristine-tar within Debian. But we want to support it.)
We have been having conversations with Debusine folks about what integration between tag2upload and Debusine would look like. We’re making some progress there, but a lot is still up in the air.
We are considering how best to provide tag2upload pre-checks as part of Salsa CI. There are several problems detected by the tag2upload service that could be detected by Salsa CI too, but which can’t be detected by git-debpush.
We’ve been monitoring the service and until very recently we have investigated every service-side failure, to understand the root causes. This has given us insight into the kinds of things our users want, and the kinds of packaging and git practices that are common. We’ve been able to improve the system’s handling of various anomalies and also improved the documentation.
Right now our failure rate is still rather high, at around 7%. Partly this is because people are trying out the system on packages that haven’t ever seen git tooling with such a level of rigour.
There are two classes of problem that are responsible for the vast majority of the failures that we’re still seeing:
tag2upload, like git (and like dgit), hates it when you reuse a version number, or try to pretend that a (perhaps busted) release never happened.
git tags aren’t namespaced, and tend to spread about promiscuously. So replacing a signed git tag, with a different tag of the same name, is a bad idea. More generally, reusing the same version number for a different (signed!) package is poor practice. Likewise, it’s usually a bad idea to remove changelog entries for versions which were actually released, just because they were later deemed improper.
We understand that many Debian contributors have gotten used to this kind of thing. Indeed, tools like dcut encourage it. It does allow you to make things neat-looking, even if you’ve made mistakes - but really it does so by covering up those mistakes!
The bottom line is that tag2upload can’t support such history-rewriting. If you discover a mistake after you’ve signed the tag, please just burn the version number and add a new changelog stanza.
One bonus of tag2upload’s approach is that it will discover if you are accidentally overwriting an NMU, and report that as an error.
tag2upload promises that the source package that it generates corresponds precisely to the git tree you tag and sign.
Orig tarballs make this complicated. They aren’t present on your laptop when you git-debpush. When you’re not uploading a new upstream version, the tag2upload service reuses existing orig tarballs from the archive. If your git and the archive’s orig don’t agree, the tag2upload service will report an error, rather than upload a package with contents that differ from your git tag.
With the most common Debian workflows, everything is fine:
If you base everything on upstream git, and make your orig tarballs with git archive (or git deborig), your orig tarballs are the same as the git, by construction. We recommend usually ignoring upstream tarballs: most upstreams work in git, and their tarballs can contain weirdness that we don’t want. (At worst, the tarball can contain an attack that isn’t visible in git, as with xz!)
Alternatively, if you use gbp import-orig, the differences (including an attack like Jia Tan’s) are imported into git for you. Then, once again, your git and the orig tarball will correspond.
But there are other workflows where this correspondence may not hold. Those workflows are hazardous, because the thing you’re probably working with locally for your routine development is the git view. Then, when you upload, your work is transplanted onto the orig tarball, which might be quite different - so what you upload isn’t what you’ve been working on!
This situation is detected by tag2upload, precisely because tag2upload checks that it’s keeping its promise: the source package is identical to the git view. (dgit push makes the same promise.)
We would love to have more contributors. There are some easy tasks to get started with, in bugs we’ve tagged “newcomer” — mostly UX improvements such as detecting certain problems earlier, in git-debpush.
More substantially, we are looking for help with sbuild: we’d like it to be able to work directly from git, rather than needing to build source packages: #868527.
A brand new release 0.1.14 of the RcppSimdJson
package is now on CRAN.
RcppSimdJson
wraps the fantastic and genuinely impressive simdjson library by Daniel Lemire and collaborators. Via
very clever algorithmic engineering to obtain largely branch-free code,
coupled with modern C++ and newer compiler instructions, it results in
parsing gigabytes of JSON parsed per second which is quite
mindboggling. The best-case performance is ‘faster than CPU speed’ as
use of parallel SIMD instructions and careful branch avoidance can lead
to less than one cpu cycle per byte parsed; see the video of the talk by Daniel Lemire
at QCon.
This version includes the new major
upstream release 4.0.0 with major new features including a ‘builder’
for creating JSON from the C++ side objects. This is something a little
orthogonal to the standard R usage of the package to parse and load JSON
data but could still be of interest to some.
The short NEWS entry for this release follows.
Changes in version 0.1.14
(2025-09-13)
simdjson was upgraded to version 4.0.0
(Dirk in #96
Continuous integration now relies a token for codecov.io
Locking down database access is probably the single most important thing for a system administrator or software developer to prevent their application from leaking its data. As MariaDB 11.8 is the first long-term supported version with a few new key security features, let’s recap what the most important things are every DBA should know about MariaDB in 2025.
Back in the old days, MySQL administrators had a habit of running the clumsy mysql-secure-installation script, but it has long been obsolete. A modern MariaDB database server is already secure by default and locked down out of the box, and no such extra scripts are needed. On the contrary, the database administrator is expected to open up access to MariaDB according to the specific needs of each server. Therefore, it is important that the DBA can understand and correctly configure three things:
Separate application-specific users with granular permissions allowing only necessary access and no more.
Distributing and storing passwords and credentials securely
Ensuring all remote connections are properly encrypted
For holistic security, one should also consider proper auditing, logging, backups, regular security updates and more, but in this post we will focus only on the above aspects related to securing database access.
How encrypting database connections with TLS differs from web server HTTP(S)
Even though MariaDB (and other databases) use the same SSL/TLS protocol for encrypting remote connections as web servers and HTTPS, the way it is implemented is significantly different, and the different security assumptions are important for a database administrator to grasp.
Firstly, most HTTP requests to a web server are unauthenticated, meaning the web server serves public web pages and does not require users to log in. Traditionally, when a user logs in over a HTTP connection, the username and password were transmitted in plaintext as a HTTP POST request. Modern TLS, which was previously called SSL, does not change how HTTP works but simply encapsulates it. When using HTTPS, a web browser and a web server will start an encrypted TLS connection as the very first thing, and only once established, do they send HTTP requests and responses inside it. There are no passwords or other shared secrets needed to form the TLS connection. Instead, the web server relies on a trusted third party, a Certificate Authority (CA), to vet that the TLS certificate offered by the web server can be trusted by the web browser.
For a database server like MariaDB, the situation is quite different. All users need to first authenticate and log in to the server before getting being allowed to run any SQL and getting any data out of the server. The database server and client programs have built-in authentication methods, and passwords are not, and have never been, sent in plaintext. Over the years, MySQL and its successor, MariaDB, have had multiple password authentication methods: the original SHA-1-based hashing, later double SHA-1-based mysql_native_password, followed by sha256_password and caching_sha256_password in MySQL and ed25519 in MariaDB. The MariaDB.org blog post by Sergei Golubchik recaps the history of these well.
Even though most modern MariaDB installations should be using TLS to encrypt all remote connections in 2025, having the authentication method be as secure as possible still matters, because authentication is done before the TLS connection is fully established.
To further harden the authentication agains man-in-the-middle attacks, a new password the authentication method PARSEC was introduced in MariaDB 11.8, which builds upon the previous ed25519 public-key-based verification (similar to how modern SSH does), and also combines key derivation with PBKDF2 with hash functions (SHA512,SHA256) and a high iteration count.
At first it may seem like a disadvantage to not wrap all connections in a TLS tunnel like HTTPS does, but actually not having the authentication done in a MitM resistant way regardless of the connection encryption status allows a clever extra capability that is now available in MariaDB: as the database server and client already have a shared secret that is being used by the server to authenticate the user, it can also be used by the client to validate the server’s TLS certificate and no third parties like CAs or root certificates are needed. MariaDB 11.8 was the first LTS version to ship with this capability for zero-configuration TLS.
Note that the zero-configuration TLS also works on older password authentication methods and does not require users to have PARSEC enabled. As PARSEC is not yet the default authentication method in MariaDB, it is recommended to enable it in installations that use zero-configuration TLS encryption to maximize the security of the TLS certificate validation.
Why the ‘root’ user in MariaDB has no password and how it makes the database more secure
Relying on passwords for security is problematic, as there is always a risk that they could leak, and a malicious user could access the system using the leaked password. It is unfortunately far too common for database passwords to be stored in plaintext in configuration files that are accidentally committed into version control and published on GitHub and similar platforms. Every application or administrative password that exists should be tracked to ensure only people who need it know it, and rotated at regular intervals to ensure old employees etc won’t be able to use old passwords. This password management is complex and error-prone.
Replacing passwords with other authentication methods is always advisable when possible. On a database server, whoever installed the database by running e.g. apt install mariadb-server, and configured it with e.g. nano /etc/mysql/mariadb.cnf, already has full root access to the operating system, and asking them for a password to access the MariaDB database shell is moot, since they could circumvent any checks by directly accessing the files on the system anyway. Therefore, MariaDB, since version 10.4 stopped requiring the root user to enter a password when connecting locally, and instead checks using socket authentication whether the user is the operating-system root user or equivalent (e.g. running sudo). This is an elegant way to get rid of a password that was actually unnecessary to begin with. As there is no root password anymore, the risk of an external user accessing the database as root with a leaked password is fully eliminated.
Note that socket authentication only works for local connections on the same server. If you want to access a MariaDB server remotely as the root user, you would need to configure a password for it first. This is not generally recommended, as explained in the next section.
Create separate database users for normal use and keep ‘root’ for administrative use only
Out of the box a MariaDB installation is already secure by default, and only the local root user can connect to it. This account is intended for administrative use only, and for regular daily use you should create separate database users with access limited to the databases they need and the permissions required.
The most typical commands needed to create a new database for an app and a user the app can use to connect to the database would be the following:
sqlCREATE DATABASE app_db;
CREATE USER 'app_user'@'%' IDENTIFIED BY 'your_secure_password';
GRANT ALL PRIVILEGES ON app_db.* TO 'app_user'@'%';
FLUSH PRIVILEGES;
Alternatively, if you want to use the parsec authentication method, run this to create the user:
sqlCREATE OR REPLACE USER 'app_user'@'%'
IDENTIFIED VIA parsec
USING PASSWORD('your_secure_password');
CREATEORREPLACEUSER'app_user'@'%' IDENTIFIED VIA parsec
USING PASSWORD('your_secure_password');
Note that the plugin auth_parsec is not enabled by default. If you see the error message ERROR 1524 (HY000): Plugin 'parsec' is not loaded fix this by running INSTALL SONAME 'auth_parsec';.
In the CREATE USER statements, the @'%' means that the user is allowed to connect from any host. This needs to be defined, as MariaDB always checks permissions based on both the username and the remote IP address or hostname of the user, combined with the authentication method. Note that it is possible to have multiple user@remote combinations, and they can have different authentication methods. A user could, for example, be allowed to log in locally using the socket authentication and over the network using a password.
If you are running a custom application and you know exactly what permissions are sufficient for the database users, replace the ALL PRIVILEGES with a subset of privileges listed in the MariaDB documentation.
For new permissions to take effect, restart the database or run FLUSH PRIVILEGES.
Allow MariaDB to accept remote connections and enforce TLS
Using the above 'app_user'@'%' is not enough on its own to allow remote connections to MariaDB. The MariaDB server also needs to be configured to listen on a network interface to accept remote connections. As MariaDB is secure by default, it only accepts connections from localhost until the administrator updates its configuration. On a typical Debian/Ubuntu system, the recommended way is to drop a new custom config in e.g. /etc/mysql/mariadb.conf.d/99-server-customizations.cnf, with the contents:
[mariadbd]
# Listen for connections from anywhere
bind-address = 0.0.0.0
# Only allow TLS encrypted connections
require-secure-transport = on
[mariadbd]
# Listen for connections from anywhere
bind-address = 0.0.0.0
# Only allow TLS encrypted connections
require-secure-transport = on
For settings to take effect, restart the server with systemctl restart mariadb. After this, the server will accept connections on any network interface. If the system is using a firewall, the port 3306 would additionally need to be allow-listed.
To confirm that the settings took effect, run e.g. mariadb -e "SHOW VARIABLES LIKE 'bind_address';" , which should now show 0.0.0.0.
When allowing remote connections, it is important to also always define require-secure-transport = on to enforce that only TLS-encrypted connections are allowed. If the server is running MariaDB 11.8 and the clients are also MariaDB 11.8 or newer, no additional configuration is needed thanks to MariaDB automatically providing TLS certificates and appropriate certificate validation in recent versions.
On older long-term-supported versions of the MariaDB server one would have had to manually create the certificates and configure the ssl_key, ssl_cert and ssl_ca values on the server, and distribute the certificate to the clients as well, which was cumbersome, so good it is not required anymore. In MariaDB 11.8 the only additional related config that might still be worth setting is tls_version = TLSv1.3 to ensure only the latest TLS protocol version is used.
Finally, test connections to ensure they work and to confirm that TLS is used by running e.g.:
--------------
mariadb from 11.8.3-MariaDB, client 15.2 for debian-linux-gnu (x86_64)
...
Current user: app_user@192.168.1.66
SSL: Cipher in use is TLS_AES_256_GCM_SHA384, cert is OK
...
--------------
mariadb from 11.8.3-MariaDB, client 15.2 for debian-linux-gnu (x86_64)
...
Current user: app_user@192.168.1.66
SSL: Cipher in use is TLS_AES_256_GCM_SHA384, cert is OK
...
If running a Debian/Ubuntu system, see the bundled README with zcat /usr/share/doc/mariadb-server/README.Debian.gz to read more configuration tips.
Should TLS encryption be used also on internal networks?
If a database server and app are running on the same private network, the chances that the connection gets eavesdropped on or man-in-the-middle attacked by a malicious user are low. However, it is not zero, and if it happens, it can be difficult to detect or prove that it didn’t happen. The benefit of using end-to-end encryption is that both the database server and the client can validate the certificates and keys used, log it, and later have logs audited to prove that connections were indeed encrypted and show how they were encrypted.
If all the computers on an internal network already have centralized user account management and centralized log collection that includes all database sessions, reusing existing SSH connections, SOCKS proxies, dedicated HTTPS tunnels, point-to-point VPNs, or similar solutions might also be a practical option. Note that the zero-configuration TLS only works with password validation methods. This means that systems configured to use PAM or Kerberos/GSSAPI can’t use it, but again those systems are typically part of a centrally configured network anyway and are likely to have certificate authorities and key distribution or network encryption facilities already set up.
In a typical software app stac however, the simplest solution is often the best and I recommend DBAs use the end-to-end TLS encryption in MariaDB 11.8 in most cases.
Hopefully with these tips you can enjoy having your MariaDB deployments both simpler and more secure than before!
It's been a while since the last performance check of Transparent Data Encryption (TDE) in Cybertec's PGEE distribution - that was in 2016. Of course, the question is still interesting, so I did some benchmarks.
Since the difference is really small between running without any extras, with data checksums turned on, and with both encryption and checksums turned on, we need to pick a configuration that will stress-test these features the most. So in the spirit of making PostgreSQL deliberately run slow, I went with only 1MB of shared_buffers with a pgbench workload of scale factor 50. The 770MB of database size will easily fit into RAM. However, having such a small buffer cache setting will cause a lot of cache misses with pages re-read from the OS disk cache, checksums checked, and the page decrypted again. To further increase the effect, I ran pgbench --skip-some-updates so the smaller, in-cache-anyway pgbench tables are not touched. Overall, this yields a pretty consistent buffer cache hit rate of only 82.8%.
Here are the PGEE 17.6 tps (transactions per second) numbers averaged over a few 1-minute 3-client pgbench runs for different combinations of data checksums on/off, TDE off, and the various supported key bit lengths:
no checksums
data checksums
no TDE
2455,6
100,00 %
2449,7
99,76 %
128 bits
2440,9
99,40 %
2443,3
99,50 %
192 bits
2439,6
99,35 %
2446,1
99,61 %
256 bits
2450,3
99,78 %
2443,1
99,49 %
There is a lot of noise in the individual runtimes before averaging, so the numbers must be viewed with some care (192-bit TDE is certainly not faster with checksums than without), but if we dare to interpret these tiny differences, we can conclude the following:
The cost of enabling data checksums on this bad-cache-ratio workload is about 0.25 %.
The cost of enabling both TDE encryption and data checksums on this workload is about 0.5%.
Any workload with a better shared_buffers cache hit rate would see a lower penalty of enabling checksums and TDE than that.
Debusine is a tool designed
for Debian developers and Operating System developers in general. This posts
describes our approach to the use of JavaScript, and some practical designs we
came up with to integrate it with Django with minimal effort.
Debusine web UI and JavaScript
Debusine currently has 3 user interfaces: a client on the command line, a
RESTful API, and a Django-based Web UI.
Debusine’s web UI is a tool to interact with the system, and we want to spend
most of our efforts in creating a system that works and works well, rather than
chasing the latest and hippest of the frontend frameworks for the web.
Also, Debian as a community has an aversion to having parts of the JavaScript
ecosystem in the critical path of its core infrastructure, and in our
professional experience this aversion is not at all unreasonable.
This leads to having some interesting requirements for the web UI, that (rather
surprisingly, one would think) one doesn’t usually find advertised in many
projects:
Straightforward to create and maintain.
Well integrated with Django.
Easy to package in Debian, with as little vendoring as possible, which helps mitigate supply chain attacks
Usable without JavaScript whenever possible, for progressive
enhancement rather
than core functionality.
The idea is to avoid growing the technical complexity and requirements of the
web UI, both server-side and client-side, for functionality that is not needed
for this kind of project, with tools that do not fit well in our ecosystem.
Also, to limit the complexity of the JavaScript portions that we do develop, we
choose to limit our JavaScript browser supports to the main browser versions
packaged in Debian Stable, plus recent oldstable.
This makes JavaScript easier to write and maintain, and it also makes it less
needed, as modern HTML plus modern CSS interfaces can go a long way with less
scripting interventions.
From the start we built the UI using Bootstrap,
which helps in having responsive layouts that can also work on mobile devices.
When we started having large select fields, we introduced
Select2 to make interaction more efficient, and which
degrades gracefully to working HTML.
Both Bootstrap and Select2 are packaged in Debian.
Form validation is done server-side by Django, and we do not reimplement it
client-side in JavaScript, as we prefer the extra round trip through a form
submission to the risk of mismatches between the two validations.
In those cases where a UI task is not at all possible without JavaScript, we
can make its support mandatory as long as the same goal can be otherwise
achieved using the debusine client command.
Django messages as Bootstrap toasts
Django has a Messages framework
that allows different parts of a view to push messages to the user, and it is
useful to signal things like a successful form submission, or warnings on
unexpected conditions.
Django messages integrate well with Bootstrap
toasts, which use a
recognisable notification language, are nicely dismissible and do not invade
the rest of the page layout.
Doing so was surprisingly simple: we handle the toasts as usual, and also render the
plain alerts inside a <noscript> tag.
This is precisely the intended usage of the <noscript> tag, and it works
perfectly: toasts are displayed by JavaScript when it’s available, or rendered
as alerts when not.
The resulting Django template is something like this:
Debusine is built around
workspaces,
which are, among other things, containers for resources.
Workspaces can inherit from other workspaces, which act as fallback lookups for
resources. This allows, for example, to maintain an experimental package to be
built on Debian Unstable, without the need to copy the whole Debian Unstable
workspace. A workspace can inherit from multiple others, which are looked up in
order.
When adding UI to configure workspace
inheritance, we
faced the issue that plain HTML forms do not have a convenient way to perform
data entry of an ordered list.
We initially built the data entry around Django formsets, which support
ordering
using an extra integer input field to enter the ordering position. This works,
and it’s good as a fallback, but we wanted something more appropriate, like
dragging and dropping items to reorder them, as the main method of interaction.
Our final approach
renders the plain formset inside a <noscript> tag, and the JavaScript widget
inside a display: none element, which is later shown by JavaScript code.
As the workspace inheritance is edited, JavaScript serializes its state into
<form type='hidden'> fields that match the structure used by the formset, so
that when the form is submitted, the view performs validation and updates the
server state as usual without any extra maintenance burden.
Serializing state as hidden form fields looks a bit vintage, but it is an
effective way of preserving the established data entry protocol between the
server and the browser, allowing us to do incremental improvement of the UI
while minimizing the maintenance effort.
More to come
Debusine is now gaining significant adoption and is still under active
development, with new features like personal archives coming soon.
This will likely mean more user stories for the UI, so this is a design space
that we are going to explore again and again in the coming future.
Please consider supporting my work in Debian and elsewhere through Liberapay.
Debian stable updates work through three main channels: point releases, security repositories, and the updates repository. Understanding these ensures your system stays secure and current.
A note about suite names
Every Debian release, or suite, has a codename — the most recent major release was trixie, or Debian 13. The codename uniquely identifies that suite.
We also use changeable aliases to add meaning to the suite’s lifecycle. For example, trixie currently has the alias stable, but when forky becomes stable instead, trixie will become known as oldstable.
This post uses either codenames or aliases depending on context. In source lists, codenames are generally preferred since that avoids surprise major upgrades right after a release is made.
The stable suites (point releases)
stable and oldstable (currently trixie and bookworm) are only updated during a “point release.” This is a minor update released to a major version. For example, 13.1 is the first minor update to trixie. It’s not possible to install older minor versions of a suite except via the snapshots mechanism (not covered here). It’s possible to view past versions via snapshot.debian.org, which preserves historical Debian archives.
There are also the testing and unstable aliases for the development suites. However, these are not relevant for users who want to run officially released versions.
Almost every stable installation of Debian will be opted into a stable or oldstable base suite. An example APT source might look like:
Type: deb
URIs: http://deb.debian.org/debian
Suites: trixie
Components: main
Signed-By: /usr/share/keyrings/debian-archive-keyring.pgp
Or, in legacy sources.list style:
deb https://deb.debian.org/debian trixie main
The security suites (DSAs explained)
For urgent security-related updates, the Security Team maintains a counterpart suite for each stable suite. These are called stable-security and oldstable-security when maintained by Debian’s security team, and oldstable-security, oldoldstable-security, etc when maintained by the LTS team.
Example APT source:
Type: deb
URIs: https://deb.debian.org/debian-security
Suites: trixie-security
Components: main
Signed-By: /usr/share/keyrings/debian-archive-keyring.pgp
Or, in legacy sources.list style:
deb https://deb.debian.org/debian-security trixie-security main
For urgent non-security updates, the final recommended suites are stable-updates and oldstable-updates. This is where updates staged for a point release, but needed sooner, are published. Examples include virus database updates, timezone changes, urgent bug fixes for specific problems and corrections to errors in the release process itself.
Example APT source:
Type: deb
URIs: https://deb.debian.org/debian
Suites: trixie-updates
Components: main
Signed-By: /usr/share/keyrings/debian-archive-keyring.pgp
Or, in legacy sources.list style:
deb https://deb.debian.org/debian trixie-updates main
Debian enables the updates suites by default. Stable Update Announcements (SUAs) are published to debian-stable-announce@lists.debian.org. This is also where announcements of forthcoming point releases are published.
Summary
These are the recommended suites for all production Debian systems:
Suite
Example codename
Purpose
Announcements
stable
trixie
Base suite containing all the available software for a release. Point releases every 2–4 months including lower-severity security fixes that do not require immediate release.
After a release moves from oldstable to unsupported status, Long Term Support (LTS) takes over for several more years. LTS provides urgent security updates for selected architectures. For details, see wiki.debian.org/LTS.
If you’d like to stay informed, the official Debian announcement lists and release.debian.org share the latest schedules and updates.
In my post yesterday, ARM is great, ARM is terrible (and so is RISC-V), I described my desire to find ARM hardware with AES instructions to support full-disk encryption, and the poor state of the OS ecosystem around the newer ARM boards.
I was anticipating buying either a newer ARM SBC or an x86 mini PC of some sort.
More-efficient AES alternatives
Always one to think, “what if I didn’t have to actually buy something”, I decided to research whether it was possible to use encryption algorithms that are more performant on the Raspberry Pi 4 I already have.
The answer was yes. From cryptsetup benchmark:
root@mccoy:~# cryptsetup benchmark --cipher=xchacha12,aes-adiantum-plain64
# Tests are approximate using memory only (no storage IO).
# Algorithm | Key | Encryption | Decryption
xchacha12,aes-adiantum 256b 159.7 MiB/s 160.0 MiB/s
xchacha20,aes-adiantum 256b 116.7 MiB/s 169.1 MiB/s
aes-xts 256b 52.5 MiB/s 52.6 MiB/s
With best-case reads from my SD card at 45MB/s (with dd if=/dev/mmcblk0 of=/dev/null bs=1048576 status=progress), either of the ChaCha-based algorithms will be fast enough. “Great,” I thought. “Now I can just solve this problem without spending a dollar.”
But not so fast.
Serial terminals vs. serial consoles
My primary use case for this device is to drive my actual old DEC vt510 terminal. I have long been able to do that by running a getty for my FTDI-based USB-to-serial converter on /dev/ttyUSB0. This gets me a login prompt, and I can do whatever I need from there.
This does not get me a serial console, however. The serial console would show kernel messages and could be used to interact with the pre-multiuser stages of the system — that is, everything before the loging prompt. You can use it to access an emergency shell for repair, etc.
Although I have long booted that kernel with console=tty0 console=ttyUSB0,57600, the serial console has never worked but I’d never bothered investigating because the text terminal was sufficient.
You might be seeing where this is going: to have root on an encrypted LUKS volume, you have to enter the decryption password in the pre-multiuser environment (which happens to be on the initramfs).
So I started looking. First, I extracted the initrd with cpio and noticed that the ftdi_sio and usbserial modules weren’t present. Added them to /etc/initramfs-tools/modules and rebooted; no better.
So I found the kernel’s serial console guide, which explicitly notes “To use a serial port as console you need to compile the support into your kernel”. Well, I have no desire to custom-build a kernel on a Raspberry Pi with MicroSD storage every time a new kernel comes out.
I thought — well I don’t stricly need the kernel to know about the console on /dev/ttyUSB0 for this; I just need the password prompt — which comes from userspace — to know about it.
So I looked at the initramfs code, and wouldn’t you know it, it uses /dev/console. Looking at /proc/consoles on that system, indeed it doesn’t show ttyUSB0. So even though it is possible to load the USB serial driver in the initramfs, there is no way to make the initramfs use it, because it only uses whatever the kernel recognizes as a console, and the kernel won’t recognize this. So there is no way to use a USB-to-serial adapter to enter a password for an encrypted root filesystem.
Drat.
The on-board UARTs?
I can hear you know: “The Pi already has on-board serial support! Why not use that?”
Ah yes, the reason I don’t want to use that is because it is difficult to use that, particularly if you want to have RTS/CTS hardware flow control (or DTR/DSR on these old terminals, but that’s another story, and I built a custom cable to map it to RTS/CTS anyhow).
Since you asked, I’ll take you down this unpleasant path.
The GPIO typically has only 2 pins for serial communication: 8 and 10, for TX and RX, respectively.
But dive in and you get into a confusing maze of UARTs. The “mini UART”, the one we are mostly familiar with on the Pi, does not support hardware flow control. The PL011 does. So the natural question is: how do we switch to the PL011, and what pins does it use? Great questions, and the answer is undocumented, at least for the Pi 4.
According to that page, for the Pi 4, the primary UART is UART1, UART1 is the mini UART, “the secondary UART is not normally present on the GPIO connector” and might be used by Bluetooth anyway, and there is no documented pin for RTS/CTS anyhow. (Let alone some of the other lines modems use) There are supposed to be /dev/ttyAMA* devices, but I don’t have those. There’s an enable_uart kernel parameter, which does things like stop the mini UART from changing baud rates every time the VPU changes clock frequency (I am not making this up!), but doesn’t seem to control the PL011 UART selection. This page has a program to do it, and map some GPIO pins to RTS/CTS, in theory.
Even if you get all that working, you still have the problem that the Pi UARTs (all of them of every type) is 3.3V and RS-232 is 5V, so unless you get a converter, you will fry your Pi the moment you connect it to something useful. So, you’re probably looking at some soldering and such just to build a cable that will work with an iffy stack.
So, I could probably make it work given enough time, but I don’t have that time to spare working with weird Pi serial problems, so I have always used USB converters when I need serial from a Pi.
Conclusion
I bought a fanless x86 micro PC with a N100 chip and all the ports I might want: a couple of DB-9 serial ports, some Ethernet ports, HDMI and VGA ports, and built-in wifi. Done.
My trip to pgday.at started Wednesday at the airport in Düsseldorf. I was there on time, and the plane started with an estimated flight time of about 90 minutes. About half an hour into the flight, the captain announced that we would be landing in 30 minutes - in Düsseldorf, because of some unspecified technical problems. Three hours after the original departure time, the plane made another attempt, and we made it to Vienna.
On the plane I had already met Dirk Krautschick who had the great honor of bringing Slonik (in the form of a big extra bag) to the conference, and we took a taxi to the hotel. On the taxi, the next surprise happened: Hans-Jürgen Schönig unfortunately couldn't make it to the conference, and his talks had to be replaced. I had submitted a talk to the conference, but it was not accepted, and neither queued on the reserve list. But two speakers on the reserve list had cancelled, and another was already giving a talk in parallel to the slot that had to be filled, so Pavlo messaged me if I could hold the talk - well of course I could. Before, I didn't have any specific plans for the evening yet, but suddenly I was a speaker, so I joined the folks going to the speakers dinner at the Wiener Grill Haus two corners from the hotel. It was a very nice evening, chatting with a lot of folks from the PostgreSQL community that I had not seen for a while.
Thursday was the conference day. The hotel was a short walk from the venue, the Apothekertrakt in Vienna's Schloss Schönbrunn. The courtyard was already filled with visitors registering for the conference. Since I originally didn't have a talk scheduled, I had signed up to volunteer for a shift as room host. We got our badge and swag bag, and I changed into the "crew" T-shirt.
The opening and sponsor keynotes took place in the main room, the Orangerie. We were over 100 people in the room, but apparently still not enough to really fill it, so the acoustics with some echo made it a bit difficult to understand everything. I hope that part can be improved for next time (which is planned to happen!).
I was host for the Maximilian room, where the sponsor sessions were scheduled in the morning. The first talk was by our Peter Hofer, also replacing the absent Hans. He had only joined the company at the beginning of the same week, and was already tasked to give Hans' talk on PostgreSQL as Open Source. Of course he did well.
Next was Tanmay Sinha from Readyset. They are building a system that caches expensive SQL queries and selectively invalidates the cache whenever any data used by these queries changes. Whenever actually fixing the application isn't feasible, that system looks like an interesting alternative to manually maintaining materialized views, or perhaps using pg_ivm.
After lunch, I went to Federico Campoli's Mastering Index Performance, but really spent the time polishing the slides for my talk. I had given the original version at pgconf.de in Berlin in May, and the slides were still in German, so I had to do some translating. Luckily, most slides are just git commit messages, so the effort was manageable.
The next slot was mine, talking about Modern VACUUM. I started with a recap of MVCC, vacuum and freezing in PostgreSQL, and then showed how over the past years, the system was updated to be more focused (the PostgreSQL 8.4 visibility map tells vacuum which pages to visit), faster (12 made autovacuum run 10 times faster by default), less scary (14 has an emergency mode where freezing switches to maximum speed if it runs out of time; 16 makes freezing create much less WAL) and more performant (17 makes vacuum use much less memory). In summary, there is still room for the DBA to tune some knobs (for example, the default autovacuum_max_workers=3 isn't much), but the vacuum default settings are pretty much okay these days for average workloads. Specific workloads still have a whopping 31 postgresql.conf settings at their disposal just for vacuum.
Right after my talk, there was another vacuum talk: When Autovacuum Met FinOps by Mayuresh Bagayatkar. He added practical advice on tuning the performance in cloud environments. Luckily, our contents did not overlap.
After the coffee break, I was again room host, now for Floor Drees and Contributing to Postgres beyond code. She presented the various ways in which PostgreSQL is more than just the code in the Git repository: translators, web site, system administration, conference organizers, speakers, bloggers, advocates. As a member of the PostgreSQL Contributors Committee, I could only approve and we should closer cooperate in the future to make people's contributions to PostgreSQL more visible and give them the recognition they deserve.
That was already the end of the main talks and everyone rushed to the Orangerie for the lightning talks. My highlight was the Sheldrick Wildlife Trust. Tickets for the conference had included the option to donate for the elephants in Kenya, and the talk presented the trust's work in the elephant orphanage there.
After the conference had officially closed, there was a bonus track: the Celebrity DB Deathmatch, aptly presented by Boriss Mejias. PostgreSQL, MongoDB, CloudDB and Oracle were competing for the grace of a developer. MongoDB couldn't stand the JSON workload, CloudDB was dismissed for handing out new invoices all the time, and Oracle had even brought a lawyer to the stage, but then lost control over a literally 10 meter long contract with too much fine print. In the end, PostgreSQL (played by Floor) won the love of the developer (played by our Svitlana Lytvynenko).
The day closed with a gathering at the Brandauer Schlossbräu - just at the other end of the castle ground, but still a 15min walk away. We enjoyed good beer and Kaiserschmarrn. I went back to the hotel a bit before midnight, but some extended that time quite some bit more.
On Friday, my flight back was only in the afternoon, so I spent some time in morning in the Technikmuseum just next to the hotel, enjoying some old steam engines and a live demonstration of Tesla coils. This time, the flight actually went to the destination, and I was back in Düsseldorf in the late afternoon.
In summary, pgday.at was a very nice event in a classy location. Thanks to the organizers for putting in all the work - and next year, Hans will hopefully be present in person!
Today I was very pleasantly surprised, while reading the column titled
«Can’t we have nice
things» Kode
Vicious answers to a question on why computing has nothing comparable to
the beauty of ancient physics laboratories turned into museums
(i.e. Faraday’s laboratory) by giving a great hat tip to a project stemmed
off Debian, and where many of my good Debian friends spend a lot of their
energies: Reproducible builds. KV says:
Once the proper measurement points are known, we want to constrain the
system such that what it does is simple enough to understand and easy to
repeat. It is quite telling that the push for software that enables
reproducible builds only really took off after an embarrassing widespread
security issue ended up affecting the entire Internet. That there had
already been 50 years of software development before anyone thought that
introducing a few constraints might be a good idea is, well, let’s just
say it generates many emotions, none of them happy, fuzzy ones.
Yes, KV is a seasoned free software author. But I found it heart warming
that the Reproducible Builds project is mentioned without needing to
introduce it (assuming familiarity across the computing industry and
academia), recognized as game-changing as we understood it would be over
ten years ago when it was first announced, and enabling of beauty in
computing.
Congratulations to all of you who have made this possible!
The month of August marked the release of Debian 13 (codename “trixie”). This is worth noting because it brought with it the return of the customary fast development pace of Debian unstable, which included several contributions from LTS Team members. More on that below.
Of the many security updates which were published (and a few non-security updates as well), some notable ones are highlighted here.
Notable security updates:
gnutls28 prepared by Adrian Bunk, fixes several potential denial of service vulnerabilities
apache2, prepared by Bastien Roucariès, fixes several vulnerabilities including a potential denial of service and SSL/TLS-related access control
mbedtls (original update, regression update) prepared by Andrej Shadura, fixes several potential denial of service and information disclosure vulnerabilities
openjdk-17, prepared by Emilio Pozuelo Monfort, fixes several vulnerabilities which could result in denial of service, information disclosure or weakened TLS connections
Notable non-security updates:
distro-info-data, prepared by Stefano Rivera, adds information concerning future Debian and Ubuntu releases
ca-certificates-java, prepared by Bastien Roucariès, fixes some bugs which could disrupt future updates
The LTS Team continues to welcome the collaboration of maintainers from across the Debian community. The contributions of maintainers from outside the LTS Team include: postgresql-13 (Christoph Berg), sope (Jordi Mallach), thunderbird (Carsten Schoenert), and iperf3 (Roberto Lumbreras).
Finally, LTS Team members also contributed updates of the following packages:
redis (to stable), prepared by Chris Lamb
firebird3.0 (to oldstable and stable), prepared by Adrian Bunk
node-tmp (to oldstable, stable, and unstable), prepared by Adrian Bunk
openjpeg2 (to oldstable, stable, and unstable), prepared by Adrian Bunk
apache2 (to oldstable), prepared by Bastien Roucariès
unbound (to oldstable), prepared by Guilhem Moulin
luajit (to oldstable), prepared by Guilhem Moulin
golang-github-gin-contrib-cors (to oldstable and stable), prepared by Thorsten Alteholz
libcoap3 (to stable), prepared by Thorsten Alteholz
libcommons-lang-java and libcommons-lang3-java (both to unstable), prepared by Daniel Leidert
python-flask-cors (to oldstable), prepared by Daniel Leidert
The LTS Team would especially like to thank our many longtime friends and sponsors for their support and collaboration.
Preparing for setup.py install deprecation, by Colin Watson
setuptools upstream will be removing the setup.py install command
on 31 October. While this may not trickle down immediately into Debian, it does
mean that in the near future nearly all Python packages will have to use
pybuild-plugin-pyproject (though they don’t necessarily have to use
pyproject.toml; this is just a question of how the packaging runs the build
system). Some of the Python team talked about this a bit at DebConf, and Colin
volunteered to write up some notes
on cases where this isn’t straightforward. This page will likely grow as the
team works on this problem.
Salsa CI, by Santiago Ruano Rincón
Santiago fixed some pending issues in the MR that moves the pipeline to sbuild+unshare,
and after several months, Santiago was able to mark the MR as ready. Part of the
recent fixes include handling external repositories,
honoring the RELEASE autodetection from d/changelog
(thanks to Ahmed Siam for spotting the main reason of the issue), and fixing a
regression about the apt resolver for *-backports releases.
Santiago is currently waiting for a final review and approval from other members
of the Salsa CI team, and being able to merge it. Thanks to all the folks who
have helped testing the changes or provided feedback so far. If you want to test
the current MR, you need to include the following pipeline definition in your
project’s CI config file:
As a reminder, this MR will make the Salsa CI pipeline build the packages more
similar to how it’s built by the Debian official builders. This will also save
some resources, since the default pipeline will have one stage less (the
provisioning) stage, and will make it possible for more projects to be built on
salsa.debian.org (including large projects and
those from the OCaml ecosystem), etc. See the different issues being fixed in
the MR description.
Debian 13 “trixie” release, by Emilio Pozuelo Monfort
On August 9th, Debian 13 “trixie” was released, building on two years worth of
updates and bug fixes from hundreds of developers. Emilio helped coordinate the
release, communicating with several teams involved in the process.
DebConf 26 Site Visit, by Stefano Rivera
Stefano visited Santa Fe, Argentina, the site for DebConf 26
next year. The aim of the visit was to help build a local team and see the
conference venue first-hand. Stefano and Nattie represented the DebConf
Committee. The local team organized Debian meetups in Buenos Aires and Santa Fe,
where Stefano presented a talk
on Debian and DebConf. Venues were scouted
and the team met with the university management and local authorities.
Miscellaneous contributions
Raphaël updated tracker.debian.org after the
“trixie” release to add the new “forky” release in the set of monitored
distributions.
He also reviewed and deployed the work of Scott Talbert
showing open merge requests from salsa in the “action needed” panel.
Raphaël reviewed some DEP-3 changes
to modernize the embedded examples in light of the broad git adoption.
Raphaël configured new workflows
on debusine.debian.net to upload to “trixie” and
trixie-security, and officially announced the service
on debian-devel-announce, inviting Debian developers to try the service for
their next upload to unstable.
Carles created a merge request
for django-compressor upstream to fix an error when concurrent node processing
happened. This will allow removing a workaround
added in openstack-dashboard and avoid the same bug in other projects that use
django-compressor.
Carles prepared a system to detect packages that Recommends packages which
don’t exist in unstable. Processed (either reported
or ignored due to mis-detected problems or temporary problems) 16% of the
reports. Will continue next month.
Carles got familiar and gave feedback for the freedict-wikdict package.
Planned contributions with the maintainer to improve the package.
Helmut responded to queries related to /usr-move.
Helmut adapted crossqa.d.n to the release of
“trixie”.
Helmut diagnosed sufficient failures in rebootstrap
to make it work with gcc-15.
Faidon discovered that the Multi-Arch hinter would emit confusing hints about
:any annotations. Helmut identified the root cause to be the handling of
virtual packages and fixed it.
Colin upgraded about 70 Python packages to new upstream versions, which is
around 10% of the backlog; this included a complicated Pydantic upgrade in
collaboration with the Rust team.
Colin fixed
a bug in debbugs that caused incoming emails to bugs.debian.org with certain
header contents to go missing.
Thorsten uploaded sane-airscan, which was already in experimental, to unstable.
Thorsten created a script to automate the upload of new upstream versions of
foomatic-db. The database contains information about printers and regularly gets
an update. Now it is possible to keep the package more up to date in Debian.
Stefano prepared updates to almost all of his packages that had new versions
waiting to upload to unstable. (beautifulsoup4, hatch-vcs, mkdocs-macros-plugin,
pypy3, python-authlib, python-cffi, python-mitogen, python-pip, python-pipx,
python-progress, python-truststore, python-virtualenv, re2, snowball, soupsieve).
Stefano uploaded two new python3.13 point releases to unstable.
Stefano updated distro-info-data in stable releases, to document the “trixie”
release and expected EoL dates.
Stefano did some debian.social sysadmin work (keeping up quotas with growing
databases and filesystems).
Stefano supported the Debian treasurers in processing some of the DebConf 25
reimbursements.
Lucas uploaded ruby3.4 to experimental. It was already approved by FTP masters.
Lucas uploaded ruby-defaults to experimental to add support for ruby3.4. It
will allow us to start triggering test rebuilds and catch any FTBFS with ruby3.4.
Lucas did some administrative work for Google Summer of Code (GSoC) and
replied to some queries from mentors and students.
Anupa helped to organize release parties for Debian 13 and Debian Day events.
Anupa did the live coverage for the Debian 13 release and prepared the Bits
post for the release announcement and 32nd Debian Day as part of the Debian
Publicity team.
Anupa attended a Debian Day event
organized by FOSS club SSET as a speaker.
I’ve long been interested in new and different platforms. I ran Debian on an Alpha back in the late 1990s and was part of the Alpha port team; then I helped bootstrap Debian on amd64. I’ve got somewhere around 8 Raspberry Pi devices in active use right now, and the free NNCPNET Internet email service I manage runs on an ARM instance at a cloud provider.
ARM-based devices are cheap in a lot of ways: they use little power and there are many single-board computers based on them that are inexpensive. My 8-year-old’s computer is a Raspberry Pi 400, in fact.
So I like ARM.
I’ve been looking for ARM devices that have accelerated AES (Raspberry Pi 4 doesn’t) so I can use full-disk encryption with them. There are a number of options, since ARM devices are starting to go more mid-range. Radxa’s ROCK 5 series of SBCs goes up to 32GB RAM. The Orange Pi 5 Max and Ultra have up to 16GB RAM, as does the Raspberry Pi 5. Pine64’s Quartz64 has up to 8GB of RAM. I believe all of these have the ARM cryptographic extensions. They’re all small and most are economical.
But I also dislike ARM. There is a terrible lack of standardization in the ARM community. They say their devices run Linux, but the default there is that every vendor has their own custom Debian fork, and quite likely kernel fork as well. Most don’t maintain them very well.
Imagine if you were buying x86 hardware. You might have to manage AcerOS, Dellbian, HPian, etc. Most of them have no security support (particularly for the kernel). Some are based on Debian 11 (released in 2021), some Debian 12 (released in 2023), and none on Debian 13 (released a month ago).
That is exactly the situation we have on ARM. While Raspberry Pi 4 and below can run Debian trixie directly, Raspberry Pi has not bothered to upstream support for the Pi 5 yet, and Raspberry Pi OS is only based on Debian bookworm (released in 2023) and very explicitly does not support a key Debian feature: you can’t upgrade from one Raspberry Pi OS release to the next, so it’s a complete reinstall every 2 years instead of just an upgrade. OrangePiOS only supports Debian bookworm — but notably, their kernel is mostly stuck at 5.10 for every image they have (bookworm shipped with 6.1 and bookworm-backports supports 6.12).
Radxa has a page on running Debian on one specific board, they seem to actually not support Debian directly, but rather their fork Radxa OS. There’s a different installer for every board; for instance, this one for the Rock 4D. Looking at it, I can see that it uses files from here and here, with custom kernel, gstreamer, u-boot, and they put zfs in main for some reason.
From Pine64, the Quartz64 seems to be based on an ancient 4.6 or 4.19 kernel. Perhaps, though, one might be able to use Debian’s Pine A64+ instructions on it. Trixie doesn’t have a u-boot image for the Quartz64 but it does have device tree files for it.
RISC-V seems to be even worse; not only do we have this same issue there, but support in trixie is more limited and so is performance among the supported boards.
The alternative is x86-based mini PCs. There are a bunch based on the N100, N150, or Celeron. Many of them support AES-NI and the prices are roughly in line with the higher-end ARM units. There are some interesting items out there; for instance, the Radxa X4 SBC features both an N100 and a RP2040. Fanless mini PCs are available from a number of vendors. Companies like ZimaBoard have interesting options like the ZimaBlade also.
The difference in power is becoming less significant; it seems the newer ARM boards need 20W or 30W power supplies, and that may put them in the range of the mini PCs. As for cost, the newer ARM boards need a heat sink and fan, so by the time you add SBC, fan, storage, etc. you’re starting to get into the price range of the mini PCs.
It is great to see all the options of small SBCs with ARM and RISC-V processors, but at some point you’ve got to throw up your hands and go “this ecosystem has a lot of problems” and consider just going back to x86. I’m not sure if I’m quite there yet, but I’m getting close.
Update 2025-09-11: I found a performant encryption option for the Pi 4, but was stymied by serial console problems; see the update post.
This release is again entirely internal. It updates the code for the
just-released RcppArmadillo
15.0.2-1, in particular opts into Armadillo 15.0.2. And it makes one
small tweak to the continuous integration setup switching to the
r-ci action.
The release is summarized below.
Changes in RcppSMC
version 0.2.9 (2025-09-09)
Adjust to RcppArmadillo 15.0.* by
setting ARMA_USE_CURRENT and updating two expressions from
deprecated code
Rely on r-ci GitHub Action which includes the bootstrap
step
Armadillo is a powerful
and expressive C++ template library for linear algebra and scientific
computing. It aims towards a good balance between speed and ease of use,
has a syntax deliberately close to Matlab, and is useful for algorithm
development directly in C++, or quick conversion of research code into
production environments. RcppArmadillo
integrates this library with the R environment and language–and is
widely used by (currently) 1279 other packages on CRAN, downloaded 41.2 million
times (per the partial logs from the cloud mirrors of CRAN), and the CSDA paper (preprint
/ vignette) by Conrad and myself has been cited 644 times according
to Google Scholar.
Fairly shortly after the release of Armadillo 14.6.3 (which became
our precedig release 14.6.3),
Conrad released version
15.0.0 of Armadillo. It
contains several breaking changes which made it unsuitable for CRANas is. First, the
minimum C++ standard was lifted to C++14. There are many good reasons
for doing so, but doing it unannounced with no transition offered cannot
work at CRAN. For (mostly
historical) reasons (as C++11 was once a step up from even more archaic
code) many packages still enforce C++11. These packages would
break under Armadillo
15.0.0. With some reverse-dependency checks we quickly found that this
would affect over 200 packages. Second, Armadillo frequently deprecates
code and issues a warning offering a hint towards an improved / current
alternative. That too is good practice, and recommended. But at CRAN a deprecation warning seen
leads to NOTE and an unfixed NOTEs can lead to archival which is not
great. For that reason, we had added a global ‘muffler’ suppressing the
deprecation warnings. This was now removed in C++14 (as one can rely on
newer compiler attributes we cannot undo, whereas the old scheme just
used macros). Again, not something we can do at CRAN.
So I hatched the plan of offering both the final release
under the previous state of the world, i.e. 14.6.3, along with 15.0.0.
User could then opt-into 15.0.0 but have a fallback of 14.6.3 allowing
all packages to coexist. The first idea was to turn the fallback on only
if C++11 compilation was noticed. This lead still a lot of deprecation
warnings meaning we had to more strongly default to 14.6.3 and only if
users actively selected 15.0.* would they get it. This seemed to work.
We were still faced with two hard failures. Turns out one was local to a
since-archived package, the other reveal a bad interaction betweem Armadillo and gcc
for complex variables and lead to bug fix 15.0.1. Which I
wrapped and uploaded a week ago.
Release 15.0.1 was quickly seen as only temporary because I
overlooked two issues. Moving ‘legacy’ and ‘current’ into, respectively,
a directory of that name meant to top-level include header
armadillo remained. This broked a few use cases where
packages use a direct #include <armadillo> (which we
do not recommend as it may miss a few other settings we apply for the R
case). The other is that an old test for ‘limited’ LAPACK capabilities
made noise in some builds (for example on Windows). As (current) R
versions generally have sufficient LAPACK and BLAS, this too has been
removed.
We have tested and rested these changed extensively. The usual
repository with the logs shows eight reverse-dependency runs each of
which can take up to a day. This careful approach, together with pacing
uploads at CRAN usually works. We got a NOTE for ‘seven uploads in six
months’ for this one, but a CRAN maintainer quickly advanced it, and the
fully automated test showed no regression or other human intervention
which is nice given the set of changes, and the over 1200 reverse
dependencies.
The changes since the last announced CRAN release 14.6.3 follow.
Changes in
RcppArmadillo version 15.0.2-1 (2025-09-08)
Upgraded to Armadillo release 15.0.2-1 (Medium Roast)
Optionally use OpenMP parallelisation for fp16 matrix
multiplication
Faster vectorisation of cube tubes
Provide a top-level include file armadillo as
fallback (#480)
Retire the no-longer-needed check for insufficient LAPACK as R
now should supply a sufficient libRlapack (when used) (#483)
Two potential narrowing warnings are avoided via cast
Changes in
RcppArmadillo version 15.0.1-1 (2025-09-01)
Upgraded to Armadillo release 15.0.1-1 (Medium Roast)
Workaround for GCC compiler bug involving misoptimisation of complex
number multiplication
This version contains both 'legacy' and 'current' version of
Armadillo (see also below). Package authors should set a '#define' to
select the 'current' version, or select the 'legacy' version (also
chosen as default) if they must. See GitHub issue #475 for
more details.
Updated DESCRIPTION and README.md
Changes
in RcppArmadillo version 15.0.0-1 (2025-08-21) (GitHub Only)
Upgraded to Armadillo release 15.0.0-1 (Medium Roast)
C++14 is now the minimum required C++ standard
Aded preliminary support for matrices with half-precision fp16
element type
Added second form of cond() to allow detection of
failures
Added repcube()
Added .freeze() and .unfreeze() member
functions to wall_clock
Extended conv() and conv2() to accept
the "valid" shape argument
Also includes Armadillo 14.6.3 as fallback for C++11
compilations
This new 'dual' setup had been rigorously tested with five
interim pre-releases of which several received full reverse-dependency
checks
This was my hundred-thirty-fourth month that I did some work for the Debian LTS initiative, started by Raphael Hertzog at Freexian. During my allocated time I uploaded or worked on:
[DLA 4272-1] aide security update of two CVEs where a local attacker can take advantage of these
flaws to hide the addition or removal of a file from the the report,
tamper with the log output, or cause aide to crash during report
printing or database listing.
[DLA 4284-1] udisks2 security update to fix one CVE related to a possible local privilege escalation.
[DLA 4285-1] golang-github-gin-contrib-cors security update to fix one CVE related to circumvention of restrictions.
[#1112054] trixie-pu of golang-github-gin-contrib-cors, prepared and uploaded
[#1112335] trixie-pu of libcoap3, prepared and uploaded
[#1112053] bookworm-pu of golang-github-gin-contrib-cors, prepared and uploaded
I also continued my work on suricata and could backport all patches. Now I have to do some tests with the package. I also started to work on an openafs regression and attended the monthly LTS/ELTS meeting.
Debian ELTS
This month was the eighty-fifth ELTS month. During my allocated time I uploaded or worked on:
[ELA-1499-1] aide security update to fix one embargoed CVE in Stretch, related to a crash. The other CVE mentioned above was not affecting Stretch.
[ELA-1508-1] udisks2 security update to fix one embargoed CVE in Stretch and Buster.
I could also mark the CVEs of libcoap as not-affected.
I also attended the monthly LTS/ELTS meeting.Of course like for LTS, As suricata had been requested for Stretch as well now, I didn’t not finish my work here.
Debian Printing
This month I uploaded a new upstream version or a bugfix version of:
Yeah, Trixie has been released, the tired bones need to be awaken again :-). This month I accepted 203 and rejected 18 packages. The overall number of packages that got accepted was 243.
It’s no news that the vagrant license has changed while ago, which resulted
in less motivation to maintain it in Debian (understandably).
Unfortunately this means there are currently no official vagrant images for Debian
trixie, for reasons
Of course there are various boxes floating around on hashicorp’s vagrant cloud,
but either they do not fit my needs (too big) or i don’t consider them trustworthy
enough…
Building the images using the existing toolset is quite straight forward. The
required scripts are maintained in the Debian Vagrant
images repository.
The diffoscope maintainers are pleased to announce the release of diffoscope
version 306. This version includes the following changes:
[ Zbigniew Jędrzejewski-Szmek ]
* Fix compatibility with RPM 6.
* Use regular 'open' calls instead of the deprecated 'codecs.open'.
* Accept additional 'v' when calling 'fdtump --version'.
Welcome to the latest report from the Reproducible Builds project for August 2025. These monthly reports outline what we’ve been up to over the past month, and highlight items of news from elsewhere in the increasingly-important area of software supply-chain security. If you are interested in contributing to the Reproducible Builds project, please see the Contribute page on our website.
We are thrilled to host the eighth edition of this exciting event, following the success of previous summits in various iconic locations around the world, including Venice, Marrakesh, Paris, Berlin, Hamburg and Athens. Our summits are a unique gathering that brings together attendees from diverse projects, united by a shared vision of advancing the Reproducible Builds effort.
During this enriching event, participants will have the opportunity to engage in discussions, establish connections and exchange ideas to drive progress in this vital field. Our aim is to create an inclusive space that fosters collaboration, innovation and problem-solving.
If you’re interesting in joining us this year, please make sure to read the event page which has more details about the event and location. Registration is open until 20th September 2025, and we are very much looking forward to seeing many readers of these reports there!
Reproducible Builds and live-bootstrap at WHY2025
WHY2025 (What Hackers Yearn) is a nonprofit outdoors hacker camp that takes place in Geestmerambacht in the Netherlands (approximately 40km north of Amsterdam). The event is “organised for and by volunteers from the worldwide hacker community, and knowledge sharing, technological advancement, experimentation, connecting with your hacker peers, forging friendships and hacking are at the core of this event”.
At this year’s event, Frans Faase gave a talk on live-bootstrap, an attempt to “provide a reproducible, automatic, complete end-to-end bootstrap from a minimal number of binary seeds to a supported fully functioning operating system”.
Jens Dietrich of the Victoria University of Wellington, New Zealand and Behnaz Hassanshahi of Oracle Labs, Australia published an article this month entitled DALEQ — Explainable Equivalence for Java Bytecode which explores the options and difficulties when Java binaries are not identical despite being from the same sources, and what avenues are available for proving equivalence despite the lack of bitwise correlation:
[Java] binaries are often not bitwise identical; however, in most cases, the differences can be attributed to variations in the build environment, and the binaries can still be considered equivalent. Establishing such equivalence, however, is a labor-intensive and error-prone process.
Jens and Behnaz therefore propose a tool called DALEQ, which:
disassembles Java byte code into a relational database, and can normalise this database by applying Datalog rules. Those databases can then be used to infer equivalence between two classes. Notably, equivalence statements are accompanied with Datalog proofs recording the normalisation process. We demonstrate the impact of DALEQ in an industrial context through a large-scale evaluation involving 2,714 pairs of jars, comprising 265,690 class pairs. In this evaluation, DALEQ is compared to two existing bytecode transformation tools. Our findings reveal a significant reduction in the manual effort required to assess non-bitwise equivalent artifacts, which would otherwise demand intensive human inspection. Furthermore, the results show that DALEQ outperforms existing tools by identifying more artifacts rebuilt from the same code as equivalent, even when no behavioral differences are present.
Reproducibility regression identifies issue with AppArmor security policies
Tails developer intrigeri has tracked and followed a reproducibility regression in the generation of AppArmor policy caches, and has identified an issue with the 4.1.0 version of AppArmor.
Although initially tracked on the Tails issue tracker, intrigeri filed an issue on the upstream bug tracker. AppArmor developer John Johansen replied, confirming that they can reproduce the issue and went to work on a draft patch. Through this, John revealed that it was caused by an actual underlying security bug in AppArmor — that is to say, it resulted in permissions not (always) matching what the policy intends and, crucially, not merely a cache reproducibility issue.
Work on the fix is ongoing at time of writing.
Rust toolchain fixes
Rust Clippy is a linting tool for the Rust programming language. It provides a collection of lints (rules) designed to identify common mistakes, stylistic issues, potential performance problems and unidiomatic code patterns in Rust projects. This month, however, Sosthène Guédon filed a new issue in the GitHub requesting a new check that “would lint against non deterministic operations in proc-macros, such as iterating over a HashMap”.
Dropping support for the armhf architecture. From July 2015, Vagrant Cascadian has been hosting a ‘zoo’ of approximately 35 armhf systems which were used for building Debian packages for that architecture.
Holger Levsen also uploaded strip-nondeterminism, our program that improves reproducibility by stripping out non-deterministic information such as timestamps or other elements introduced during packaging. This new version, 1.14.2-1, adds some metadata to aid the deputy tool. ( #1111947)
diffoscope is our in-depth and content-aware diff utility that can locate and diagnose reproducibility issues. This month, Chris Lamb made the following changes, including preparing and uploading versions, 303, 304 and 305 to Debian:
Improvements:
Use sed(1) backreferences when generating debian/tests/control to avoid duplicating ourselves. […]
Move from a mono-utils dependency to versioned mono-devel | mono-utils dependency, taking care to maintain the [!riscv64] architecture restriction. […]
Use sed over awk to avoid mangling dependency lines containing = (equals) symbols such as version restrictions. […]
Bug fixes:
Fix a test after the upload of systemd-ukify version 258~rc3. […]
Ensure that Java class files are named .class on the filesystem before passing them to javap(1). […]
Do not run jsondiff on files over 100KiB as the algorithm runs in O(n^2) time. […]
Don’t check for PyPDF version 3 specifically; check for >= 3. […]
In addition, Martin Joerg fixed an issue with the HTML presenter to avoid crash when page limit is None […] and Zbigniew Jędrzejewski-Szmek fixed compatibility with RPM 6 […]. Lastly, John Sirois fixed a missing requests dependency in the trydiffoscope tool. […]
Website updates
Once again, there were a number of improvements made to our website this month including:
Chris Lamb:
Write and publish a news entry for the upcoming summit. […]
Add some assets used at FOSSY, such as the badges and the paper handouts. […]
The Reproducible Builds project operates a comprehensive testing framework running primarily at tests.reproducible-builds.org in order to check packages and other artifacts for reproducibility. In August, however, a number of changes were made by Holger Levsen, including:
Ignore that the megacli RAID controller requires packages from Debian bookworm. […]
In addition,
James Addison migrated away from deprecated toplevel deb822 Python module in favour of debian.deb822 in the bin/reproducible_scheduler.py script […] and removed a note on reproduce.debian.net note after the release of Debian trixie […].
Jochen Sprickerhof made a huge number of improvements to the reproduce.debian.net statistics calculation […][…][…][…][…][…] as well as to the reproduce.debian.net service more generally […][…][…][…][…][…][…][…].
Mattia Rizzolo performed a lot of work migrating scripts to SQLAlchemy version 2.0 […][…][…][…][…][…] in addition to making some changes to the way openSUSE reproducibility tests are handled internally. […]
Lastly, Roland Clobus updated the Debian Live packages after the release of Debian trixie. […][…]
Upstream patches
The Reproducible Builds project detects, dissects and attempts to fix as many currently-unreproducible packages as possible. We endeavour to send all of our patches upstream where appropriate. This month, we wrote a large number of such patches, including:
Finally, if you are interested in contributing to the Reproducible Builds project, please visit our Contribute page on our website. However, you can get in touch with us via:
Yesterday I posted
about the history, in numbers, of the support for autopkgtest in the Debian
archive. I had analyzed the presence of a Testsuite: field in source
packages, from wheezy to trixie, and noticed a slowdown in the growth rate of
autopkgtest support, in proportional terms. In each new release, the
percentage of packages declaring a test suite grew less than in the previous
release, for the last 4 releases.
A night of sleep and a rainy morning later, I come back with a more optimistic
view, and present to you the following data, expanded from the raw data:
Release year
Release
Yes
No
Total
Δ Yes
Δ No
Δ Total
2013
wheezy
5
17170
17175
--
--
--
2015
jessie
1112
19484
20596
1107
2314
3421
2017
stretch
5110
19735
24845
3998
251
4249
2019
buster
9966
18535
28501
4856
-1200
3656
2021
bullseye
13949
16994
30943
3983
-1541
2442
2023
bookworm
17868
16473
34341
3919
-521
3398
2025
trixie
21527
16143
37670
3659
-330
3329
A few observations:
Since stretch, we have been consistently adding autopkgtest support to
close to 4,000 packages on each release, on average.
Since buster, the number of packages withoutautopkgtest support has
decreased in the hundreds.
On average, each release has 3,400 packages more than the previous, while
also bringing 4,000 extra packages with autopkgtest support. I have the
following hypotheses for this:
a large part of new packages are added already with autopkgtests;
a smaller but reasonably large number of existing packages get
autopkgtests added on each release.
All in all, I think this data show that Debian maintainers recognize the
usefulness of automated testing and are engaged in improving our QA process.
The Release of Debian 13 ("Trixie") last month marked another milestone on the
effort to provide automated test support for Debian packages in their installed
form. We have achieved the mark of 57% of the source packages in the archive
declaring support for autopkgtest.
Release
Packages with tests
Total number of packages
% of packages with tests
wheezy
5
17175
0%
jessie
1112
20596
5%
stretch
5110
24845
20%
buster
9966
28501
34%
bullseye
13949
30943
45%
bookworm
17868
34341
52%
trixie
21527
37670
57%
The code that generated this table is provided at the bottom.
The growth rate has been consistently decreasing at each release after stretch.
That probably means that the low hanging fruit -- adding support en masse for
large numbers of similar packages, such as team-maintained packages for a given
programming language -- has been picked, and from now on the work gets slightly
harder. Perhaps there is a significant long tail of packages that will never
get autopkgtest support.
Looking for common prefixes among the packages missing a Testsuite: field
gives me us the largest groups of packages missing autopkgtest support:
There seems to be a fair amount of Haskell and Python. If someone could figure
out a way of testing installed fonts in a meaningful way, this would a be a
good niche where we can cover 300+ packages.
There is a another analysis that can be made, which I didn't: which percentage
of new packages introduced in a given release have declared autopkgtest
support, compared with the total of new packages in that release? My data only
counts the totals, so we start with the technical debt of the almost all of the
17,000 packages with no tests in wheezy, which was the stable at the time I
started Debian CI. How many of those got tests since
then?
Note that not supporting autopkgtest does not mean that a package is not
tested at all: it can run build-time tests, which are also useful. Not
supporting autopkgtest, though, means that their binaries in the archive
can't be automatically tested in their installed, but then there is a entire
horde of volunteers running testing and unstable on a daily basis who test
Debian and report bugs.
This is the script that produced the table in the beginning of this post:
#!/bin/shset-eu
extract(){local release
local url
release="$1"url="$2"if[!-f"${release}"];then
rm-f"${release}.gz"
curl --silent-o${release}.gz "${url}"gunzip"${release}.gz"fi
local with_tests
local total
with_tests="$(grep-dctrl -c-F Testsuite --regex.$release)"total="$(grep-dctrl -c-F Package --regex.$release)"echo"| ${release} | ${with_tests} | ${total} | $((100*with_tests/total))% |"}echo"| **Release** | **Packages with tests** | **Total number of packages** | **% of packages with tests** |"echo"|-------------|-------------------------|------------------------------|------------------------------|"for release in wheezy jessie stretch buster;do
extract "${release}""http://archive.debian.org/debian/dists/${release}/main/source/Sources.gz"done
for release in bullseye bookworm trixie;do
extract "${release}""http://ftp.br.debian.org/debian/dists/${release}/main/source/Sources.gz"done
There are times when an email based workflow gets really difficult. One of those times is when discussing projects related to spam and malware detection.
noahm@debian.org
host stravinsky.debian.org [2001:41b8:202:deb::311:108]
SMTP error from remote mail server after end of data:
550-malware detected: Sanesecurity.Phishing.Fake.30934.1.UNOFFICIAL:
550 message rejected
submit@bugs.debian.org
host stravinsky.debian.org [2001:41b8:202:deb::311:108]
SMTP error from remote mail server after end of data:
550-malware detected: Sanesecurity.Phishing.Fake.30934.1.UNOFFICIAL:
550 message rejected
This was, in fact, a false positive. And now, because reportbug doesn’t record outgoing messages locally, I need to retype the whole thing.
(NB. this is not a complaint about the policies deployed on the Debian mail servers; they’d be negligent if they didn’t implement such policies on today’s internet.)
Back in March, with version 4.17.0, Lean introduced partial_fixpoint, a new way to define recursive functions. I had drafted a blog post for the official Lean FRO blog back then, but forgot about it, and with the Lean FRO blog discontinued, I’ll just publish it here, better late than never.
With the partial_fixpoint mechanism we can model possibly partial functions (so those returning an Option) without an explicit termination proof, and still prove facts about them. See the corresponding section in the reference manual for more details.
On the Lean Zulip, I was asked if we can use this feature to define the McCarthy 91 function and prove it to be total. This function is a well-known tricky case for termination proofs.
First let us have a brief look at why this function is tricky to define in a system like Lean. A naive definition like
def f91 (n : Nat) : Nat :=
if n > 100
then n - 10
else f91 (f91 (n + 11))
does not work; Lean is not able to prove termination of this functions by itself.
Even using well-founded recursion with an explicit measure (e.g. termination_by 101 - n) is doomed, because we would have to prove facts about the function’s behaviour (namely that f91n = f91101 = 91 for 90 ≤ n ≤ 100) and at the same time use that fact in the termination proof that we have to provide while defining the function. (The Wikipedia page spells out the proof.)
We can make well-founded recursion work if we change the signature and use a subtype on the result to prove the necessary properties while we are defining the function. Lean by Example shows how to do it, but for larger examples this approach can be hard or tedious.
With partial_fixpoint, we can define the function as a partial function without worrying about termination. This requires a change to the function’s signature, returning an Option Nat:
def f91 (n : Nat) : Option Nat :=
if n > 100
then pure (n - 10)
else f91 (n + 11) >>= f91
partial_fixpoint
From the point of view of the logic, Option.none is then used for those inputs for which the function does not terminate.
This function definition is accepted and the function runs fine as compiled code:
#eval f91 42
prints some 91.
The crucial question is now: Can we prove anything about f91 In particular, can we prove that this function is actually total?
Since we now have the f91 function defined, we can start proving auxillary theorems, using whatever induction schemes we need. In particular we can prove that f91 is total and always returns 91 for n ≤ 100:
theorem f91_spec_high (n : Nat) (h : 100 < n) : f91 n = some (n - 10) := by
unfold f91; simp [*]
theorem f91_spec_low (n : Nat) (h₂ : n ≤ 100) : f91 n = some 91 := by
unfold f91
rw [if_neg (by omega)]
by_cases n < 90
· rw [f91_spec_low (n + 11) (by omega)]
simp only [Option.bind_eq_bind, Option.some_bind]
rw [f91_spec_low 91 (by omega)]
· rw [f91_spec_high (n + 11) (by omega)]
simp only [Nat.reduceSubDiff, Option.some_bind]
by_cases h : n = 100
· simp [f91, *]
· exact f91_spec_low (n + 1) (by omega)
theorem f91_spec (n : Nat) : f91 n = some (if n ≤ 100 then 91 else n - 10) := by
by_cases h100 : n ≤ 100
· simp [f91_spec_low, *]
· simp [f91_spec_high, Nat.lt_of_not_le ‹_›, *]
-- Generic totality theorem
theorem f91_total (n : Nat) : (f91 n).isSome := by simp [f91_spec]
(Note that theorem f91_spec_low is itself recursive in a somewhat non-trivial way, but Lean can figure that out all by itself. Use termination_by? if you are curious.)
This is already a solid start! But what if we want a function of type f91! (n : Nat) : Nat, without the Option? Then can derive that from the partial variant, as we have just proved that to be actually total:
def f91! (n : Nat) : Nat := (f91 n).get (f91_total n)
theorem f91!_spec (n : Nat) : f91! n = if n ≤ 100 then 91 else n - 10 := by
simp [f91!, f91_spec]
Using partial_fixpoint one can decouple the definition of a function from a termination proof, or even model functions that are not terminating on all inputs. This can be very useful in particular when using Lean for program verification, such as with the aeneas package, where such partial definitions are used to model Rust programs.
CAdES is a digital signature
standard that is used and sometimes mandated, by the Italian Public
Administration.
To be able to do my job, I own a Carta Nazionale dei Servizi
(CNS) with which I
can generate legally binding signatures. Now comes the problem of finding a
software to do it.
Infocamere Firma4NG
InfoCamere are distributing a
software called Firma4NG,
with a Linux option, which, I'm pleased to say, seems to work just fine.
Autofirma
AutoFirma is a Java
software for digital signatures distributed by the Spanish government, which
has a Linux version.
It is licensed as GPL-2+ | EUPL-1.1, and the source seems to be
here.
While my Spanish is decent I lack jargon for this specific field, and I didn't
manage to make it work with my CNS.
Autogram
Andrej Shadura pointed me to Autogram,
a Slovakian software for digital signatures, licensed under the EUPL-1.2.
The interface is still only in Slovakian, so tried it but I didn't go very far
in trying to make it work.
OpenSSL
In trixie, openssl is almost, but not quite, able to do it. Here's as far as I've got.
All the Italian verification
systems
I tried, however, complain that, although the signature is valid, the
certificate is emitted by an unqualified CA and the certificate revocation
information cannot be found.
PAdES
When signing PDF files, the PAdES
standard is sometimes accepted.
LibreOffice is able to generate PAdES signatures using the "File / Digital
signatures…" menu, and provided the smart card is in the reader it is able to
use it. Both LibreOffice and Okular can verify that the signature is indeed
there.
However, when trying to validate the signature using Italian validators, I get
the same complaints about unqualified CAs and missing revocation information.
Wall of shame
Dike GoSign
Infocert (now Tinexta) used to
distribute a software called "Dike GoSign" that worked on Ubuntu, which I used
on a completely isolated VM, and it was awful but it worked.
I had to regenerate the VM for it, and discovered that the version they
distribute now will refuse to work unless one signs in online with a Tinexta
account. From the same company that asks you to install their own root
certifiactes
to use their digital signature system.
Gross.
Dropped.
Aruba Sign
Aruba used to distribute a
software called Aruba Sign, which also worked on Ubuntu.
Ubuntu support has been discontinued, and they now only offer support for
Windows or Mac.
forky is
open!
As a result I’m starting to think about the upcoming Python
3.14. At some point we’ll doubtless do
a full test rebuild, but in advance of that I concluded that one of the most
useful things I could do would be to work on our very long list of packages
with new upstream
versions.
Of course there’s no real chance of this ever becoming empty since upstream
maintainers aren’t going to stop work for that long, but there are a lot of
packages there where we’re quite a long way out of date, and many of those
include fixes that we’ll need for 3.14, either directly or by fixing
interactions with new versions of other packages that in turn will need to
be fixed. We can backport changes when we need to, but more often than not
the most efficient way to do things is just to keep up to date.
So, I upgraded these packages to new upstream versions (deep breath):
setuptools upstream will be removing the setup.py install
command on 31
October. While this may not trickle down immediately into Debian, it does
mean that in the near future nearly all Python packages will have to use
pybuild-plugin-pyproject (note that this does not mean that they
necessarily have to use pyproject.toml; this is just a question of how the
packaging runs the build system). We talked about this a bit at DebConf,
and I said that I’d noticed a number of packages where this isn’t
straightforward and promised to write up some notes. I wrote the
Python/PybuildPluginPyproject
wiki page for this; I expect to add more bits and pieces to it as I find them.
On that note, I converted several packages to pybuild-plugin-pyproject:
Upgrading Pydantic was complicated, and required a rust-pyo3 transition
(which Jelmer Vernooij started and Peter Michael Green has mostly been
driving, thankfully), packaging rust-malloc-size-of (including an upstream
portability fix), and
upgrading several packages to new upstream versions:
For quite some time, I have been thinking about trying a bit of
patchwork, and English Paper Piecing looked like a technique suited to
my tastes, with the handsewing involved and the fact of having a paper
pattern of sort and everything.
The problem is, most of the scraps of fabric I get from my sewing aren’t
really suitable for quilting, with a lot of them being either too black
and too thick or too white and too thin.
On the other hand, my partner wears polo shirts at work, and while I
try to mend the holes that form, after a while the edges get worn, and
they just are no longer suitable for the office, even with some creative
mending, and they get downgraded to home wear. But then more office
shirts need to be bought, and the home ones accumulate, and there is
only so much room for polo shirts in the house, and the worst ones end
up in my creative reuse pile.
Some parts are worn out and they will end up as cabbage stuffing for
things, but some are still in decent enough conditions and could be used
as fabric.
But surely, for English Paper Piecing you’d need woven fabric, not knit,
even if it’s the dense piqué used in polo shirts, right? Especially if
it’s your first attempt at the technique, right?
Well, probably it wouldn’t work with complex shapes, but what about some
5-ish cm tall Standard Compliant bestagon? So I printed out some
hexagons on thick paper, printed some bigger hexagons with sewing
allowance as a cutting aid, found two shirts in the least me colours I
could find (and one in grey because it was the best match for the other
two) and decided to sacrifice them for the experiment.
And as long as the paper was still in the pieces, the work went nicely,
so I persevered while trying to postpone the Moment of Truth.
After a while I measured things out and saw that I could squeeze a 6.5 ×
7 hexagon pattern into something resembling a square that was a multiple
of the 2.5 cm square on the back of my Piecepack tiles, and decided to
go for another Standard for the back (because of course I wasn’t going
to buy new fabric for lining the work).
I kept the paper in the pieces until both sides were ready, and used it
to sew them right sides together, leaving the usual opening in the
middle of one side.
Then I pressed, removed the paper, turned everything inside out, pressed
again and. It worked!
The hexagons look like hexagons, the squares look like squares, the
whole thing feels soft and drapey, but structurally sound. And it’s a
bit lumpy, but not enough to cause issues when using it as a soft
surface to put over a noisy wooden table to throw dice on.
I considered adding some lightweight batting in the middle, but there
was really no need for it, and wondered about how to quilt the piece in
a way that worked with the patterns on the two sides, but for something
this small it wasn’t really required.
However, I decided to add a buttonhole stitch border on all edges, to
close the opening I had left and to reinforce especially the small
triangles on the hexagons side, as those had a smaller sewing allowance
and could use it.
And of course, the 11 × 11 squares side wasn’t completely an accident,
but part of A Plan.
And there are more polo shirts in that pile, and while they won’t be
suitable for anything complex, maybe I could try some rhombs, or even
kites and darts?
I am Spaarsh Thakkar, a final-year Computer Science Engineering undergrad from India. My interests lie in research and systems. My recent work has been in and around Graphics Processing Units and I also hold a keen interest in Computer Networks. At the time of writing, I have been an open-source contributor for almost a year.
Proposal Description (as shown on GSoC Project Profile1)
Due to Debian’s open-source nature, no Debian package in main can have a proprietary GPU package listed as a dependency. While AI and HPC workloads increasingly rely on GPU acceleration, many Debian packages still focus solely on CUDA, which is proprietary.
With the advent of ROCm, an open-source GPU computing platform, we can now integrate full-fledged AMD GPU support into Debian packages. This will improve the experience of developers working in AI/ML and HPC while positioning Debian as a strong OS choice for GPU-driven workloads. The proposal aims to aid in solving the aforementioned program by packaging several ROCm packages for debian and add ROCm support to some existing debian packages.
The deliverables are as follows:
New Debian packages with GPU support
Enhanced GPU support within existing Debian packages
More autopackagetests running on the Debian ROCm CI
Key Objectives
Enable ROCm in:
dbcsr
gloo
cp2k
Publish the following packages to debian apt archive:
hipblas-common
hipBLASlt
Work Report
1. Publishing hipblas-common to apt
This objective was successfully completed, resulting in hipblas-common being published in the apt repository2.
Securing sponsorship, which led to the package being accepted into the experimental branch of apt
Since the beginning of GSoC, the package has also been promoted to the unstable branch2.
2. DBCSR ROCm and Multi-Arch Support
During my GSoC project, I worked on extending the DBCSR (Distributed Block Compressed Sparse Row)7 package to improve its ROCm/HIP support, and handling multi-architecture GPU kernels in a way that is both practical for upstream maintainers and debian package developers.
The code changes can be found at my dbcsr fork here8.
ROCm/HIP Enablement
Enabled ROCm backend support to DBCSR, allowing GPU acceleration beyond CUDA by enabling HIP-based builds.
Investigated and resolved build issues specific to HIP kernels within DBCSR.
Multi-Architecture GPU Kernel Handling
(The following content was presented in greater detail at DebConf’25 as well. The presentation video can be found here9 and the presentation slide can be found here10).
DBCSR contains GPU kernels that are heavily optimized for specific architectures. By default, these are built for a single target architecture, which poses challenges for packaging where binaries need to support multiple possible GPU targets.
Explored different strategies for solving the multi-arch GPU kernel distribution problem, including:
Option 1: Fat binaries (embedding multiple GPU architectures into a single binary, with runtime dispatch). This is ideal for end-users but requires deeper changes upstream and is not straightforward with HIP/ROCm.
Option 2: Arch-specific libraries (e.g., libdbcsr.gfxXXX.a), where the alternatives system or explicit user selection would determine which one is used. This solves the problem but pushes complexity downstream into packaging and user configuration.
Option 3: Prefixed functions inside a single file, where kernels are compiled separately per architecture, functions are renamed with an arch prefix, and runtime logic in DBCSR decides which kernel to invoke. This shifts complexity upstream but could give a clean downstream experience.
I critically analyzed these options in the context of Debian packaging and upstream maintainability. Arch-specific .a files introduce exponential dependency complexity. The prefixed-function approach seemed like a plausible way forward, though it requires upstream buy-in.
After consulting with my mentor, these concerns were raised in the dbcsr repository as a discussion here11
Summary
My work involved:
Enabling HIP/ROCm support in DBCSR.
Prototyping strategies for handling GPU multi-arch builds.
Evaluating the trade-offs between upstream maintainability and downstream packaging complexity.
3. gloo, hipification and source code issues
One of the other packages that were targeted was gloo12. It is a collective communications library and has the implementations of different Machine Learning communication algorithms.
The code changes can be found at my gloo fork here13 (some changes have not be committed at the time of writing).
HIP/ROCm Enablement
Fixing old ROCm CMake functions
The upstream Gloo codebase still used old ROCm CMake functions that began with the hip_ prefix (for example, hip_add_executable). These functions have since been deprecated/removed. I updated the build system to use the modern ROCm CMake equivalents so that the package can build properly in a current ROCm environment.
Debian packaging changes
I modified debian/control to add a new package, libgloo-rocm, in addition to the existing packages. This allows proper separation and handling of ROCm-enabled builds in Debian.
First successful library build
After these changes, I was able to successfully build the library. However, I ran into issues when trying to produce the shared library: there were undefined symbol errors at link time.
Source Code Issue
On investigating the undefined symbol errors, I identified that these came from a lack of explicit template instantiation for some Gloo classes. Since C++ templates only get compiled when explicitly used or instantiated, this resulted in missing symbols in the shared library.
To solve this, I explored the source code and noticed that the HIP backend code was not natively written — it was generated from the CUDA backend using a custom hipification script maintained by the repo.
I experimented with modifying the HIPification process itself, trying out hipify-perl14 instead of the repository’s custom Python script.
I also tried tweaking the source code in places where template instantiations were missing, so that the ROCm build would correctly export the needed symbols.
Summary
The issue is still unresolved. The core problem lies in how the source code is structured: the HIP backend is almost entirely auto-generated from CUDA code, and the process does not handle template instantiations correctly. Because of this, the Debian package for Gloo with ROCm support is not yet ready for release, and further source-level fixes are required to make the ROCm build reliable.
4. cp2k
CP2K15 is a quantum chemistry and solid state physics software package that can perform atomistic simulations of solid state, liquid, molecular, periodic, material, crystal, and biological systems.
HIP/ROCm Enablement
cp2k depends on dbcsr and hence, HIP/ROCm enablement in this package required the dbcsr16 package to get through.
Even though dbcsr isn’t ready yet, it was worthwhile to plan how it shall be built with HIP/ROCm once we have dbcsr in place. Upon doing this, it was realized that the architecture-wise libraries provided by the dbcsr package will result in a complicated building process for cp2k.
No changes have been made to this package yet and more concrete steps shall be taken once the dbcsr package work is completed.
Summary
The multi-arch build process for cp2k maybe complicated by the one static-library-per-architecture method used in the dependent package, dbcsr.
Auxiliary Work & Activities
While working on the aformentioned GSoC Goals, there were a few other things that were also done.
While trying to enable HIP/ROCm in dbcsr, CMakeDetermineHIPCompiler.cmake was unable to find HIP runtime CMake package. After going through some similar issues faced by other developers earlier, it was decided to file a bug report under the libamdhip64-dev package.
After discussions with and trying the changes suggested by Cory (my mentor) under the bug, the issue was resolved.
Turns out, the wrong compiler was being used by me! The gcc compiler was supposed to be used and I was using hipcc. The bug was closed since it was not due an issue with the package.
Cory suggested that I add this info under the ROCm wiki page. It is yet to be done and hopefully I get it done soon.
DebConf25 Talk
After facing the multi-arch build dilemma with dbcsr (and also getting to know about the issues faced by other fellow package developers), I came to realise that this was more than a packaging, build or programming issue. GPU-packaging was facing a policy issue.
Hence, I decided to cover this problem in greater detail at my DebConf25 Virtual Presentation under the Outreach Session.
Shoutout to Cory for his support and Lucas Kanashiro for encouraging me to present my work!
Bi-Weekly AMD ROCm Meetings
Shortly after the Coding period started, Cory began the initiative of Bi-Weekly AMD ROCm Meetings18. Being a part of the meetings (participated in all but one!), seeing the work the other folks are doing and being able to discuss my own problems was a delight.
(Upcoming) IndiaFOSS 2025 Talk
After understanding the nuances and beauty of the debian packaging ecosystem in these months, I decided to spread the work about debian packaging and packaging software in general. My talk19 for the same got accepted in the upcoming IndiaFOSS 202520 conference!
I hope this beings more people towards the packaging ecosystem and to the debian developer ecosystem.
Conclusion
My GSoC time was fantastic! I plan to complete the work that I have started during my GSoC and beyond. Working with Cory21 and Utkarsh22 (a fellow GSoC’25 contributor under Cory) has been a very positive experience.
HIP/ROCm GPU-packaging is in a nascent stage. It is an exciting time to be in this space right now. The problems are new and never encountered before (CPU packaging isn’t architecture specific!). The problems were shall face in the coming time, and our solutions to them will set a precendent for the future.
For my birthday I was gifted copies of Eno's last two albums, Luminal and
Lateral, both of which are collaborations with Beatie Wolfe.
Let's start with the art. I love this semi-minimalist, bold style, and how the
LP itself (in their coloured, bio-vinyl variants) feels like it's part of the
artwork. I like the way the artist credits mirror each other: Wolfe, Eno for
Luminal; Eno, Wolfe for Lateral.
My first "bio vinyl" LP was the Cure's last one, last year. Ahead of it arriving
I planned to blog about it, but when it came arrived it turned out I had nothing
interesting to say. In terms of how it feels, or sounds, it's basically the same
as the traditional vinyl formulation.
The attraction of bio-vinyl to well-known environmentalists like Eno (and I
guess, the Cure) is the reduced environmental impact due to changing out the
petroleum and other ingredients with recycled used cooking oil.
You can read more about bio-vinyl if you wish.
I try not to be too cynical about things like this; my immediate response is
to assume some kind of green-washing PR campaign (I'm
currently reading Consumed by Saabira
Chaudhuri, an excellent book that is not sadly only fuelling my cynicism) but
I know Eno in particular takes this stuff seriously and has likely done more
than a surface-level evaluation. So perhaps every little helps.
On to the music. The first few cuts I heard from the albums earlier in the year
didn't inspire me much. Possibly I heard something from Luminal, the vocal
album; and I'm generally more drawn to Eno's ambient work. (Lateral is
ambient instrumental). I was not otherwise familiar with Beatie Wolfe. On
returning to the albums months later, I found them more compelling. Luminal
reminds me a little of Apollo: Atmospheres and Soundtracks. Lateral worked
well as space music for phd-correction sessions.
The pair recently announced a third album, Liminal, to arrive in October, and
totally throw off the symmetry of the first two. Two of its tracks are available
to stream now in the usual places.
This past month I did setup KGB to send notifications to #debian-lts when new
merge requests were created in the LTS website’s repo and I learned a couple
cool things. I’ve been trying to document things more so I don’t have to
research the same topic months later, hence the blog seemed like a good idea,
specially since many debianites have KGB set on their favorite IRC channel
and this post will go to planet.debian.org.
Selecting What Goes to IRC
Salsa (Debian’s GitLab instance) can generate a lot of
events for
things that happen on a repository and a lot of them can be pushed to KGB via
webhooks. Generally I
prefer a minimal set enabled otherwise it’s too much clutter on the IRC side,
but it’s important to go through each option to see what makes sense or not.
From the experience I had, the following ones are the most useful to have it
on:
Push events
Tag push events
Comments
Issue events
Merge request events
Pipeline events
Reducing the Noise
For Debian packaging, one may find it useful to add a pattern filter so only
the packaging branch updates go to IRC. If you are using
DEP-14, that’s pretty easy,
“debian/*” will do the job.
Notably, “Job events” are left out. Basically it’s just too much info, you get
one alert when a job is scheduled, then when it’s started and another one when
it’s completed. Well, each pipeline has at least a few of them, multiply by
three and you can understand my point.
Besides that, pipelines also generate the same amount of events as jobs, so it
might be a problem too. Well, KGB comes to the rescue. It allows you to filter
pipeline events, because you really only care about the pipeline when it fails
;-) To do just that, pipeline_only_status=failed.
Another interesting option is limiting the commits shown when the push event
has too many of them. One can do that with squash_threshold=3. Remember I
want less clutter?! Three commits is my limit here.
Final Result
The final URL for me looks like this (newlines added for clarity):
You can see there are more options than the ones I described earlier, well, now
it’s your time to go through KGB’s
documentation and learn a
thing or two ;-)
Another short status update of what happened on my side last month. Released
Phosh 0.49.0
and added some more QoL improvements to Phosh Mobile stack
(e.g. around Cell broadcasts). Also pulled my SHIFT6mq out of the
drawer (where it was sitting in a drawwer far too long) and got it to
show a picture after a small driver fix. Thanks to the work the
sdm845-mainlining folks are doing that was all that was needed. If I
can get touch to work better that would be another nice device for
demoing Phosh.
Due to the freeze I did not do that many uploads in the last few months, so
there were various new releases I packaged once Trixie was released. Regarding
the release of Debian 13, Trixie, I wrote a small summary of the changes in my
packages.
I uploaded an unreleased version of cage to experimental, to prepare for the
transition to wlroots-0.19. Both sway and labwc already had packages in
experimental that depended on the new wlroots version. When the transition
happened, I uploaded the cage version to unstable, as well as labwc 0.9.1
and sway 1.11.
In my dayjob I added extended the place lookup form of apis-core-rdf to allow
searching places and selecting them on a map using leaflet and the nominatim
API. Another issue I worked on was about highlighting those inputs of our
generic list filter that are used to filter the results. I released a couple
of bugfix releases for the v0.50 release, then v0.51 and two bugfix releases
and then v0.52 and another couple of bugfix releases. v0.53 will land in a
couple of days. I also released v0.6.2 of apis-highlighter-ng, which is sort
of a plugin for apis-core-rdf, that allows to highlight parts of a text and
link them to whatever Django object (in our case relations).
The main text below is an edited version of my original review of
Regensis written on 2012-12-21. Additional
comments from my re-read are after the original review.
Regenesis is a direct sequel to Cyteen, picking up very shortly after the end of that book and
featuring all of the same characters. It would be absolutely pointless to
read this book without first reading Cyteen; all of the emotional
resonance and world-building that make Regensis work are done
there, and you will almost certainly know whether you want to read it
after reading the first book. Besides, Cyteen is one of the best SF
novels ever written and not the novel to skip.
Because this is such a direct sequel, it's impossible to provide a good
description of Regenesis without spoiling at least characters and
general plot developments from Cyteen. So stop reading here if
you've not yet read the previous book.
I've had this book for a while, and re-read Cyteen in anticipation
of reading it, but I've been nervous about it. One of the best parts of
Cyteen is that Cherryh didn't belabor the ending, and I wasn't sure
what part of the plot could be reasonably extended. Making me more nervous
was the back-cover text that framed the novel as an investigation of who
actually killed the first Ari, a question that was fairly firmly in the
past by the end of Cyteen and that neither I nor the characters had
much interest in answering. Cyteen was also a magical blend of
sympathetic characters, taut tension, complex plotting, and wonderful
catharsis, the sort of lightning in a bottle that can rarely be caught
twice.
I need not have worried. If someone had told me that Regenesis was
another 700 pages of my favorite section of Cyteen, I would have
been dubious. But that's exactly what it is. And the characters only care
about Ari's murderer because it comes up, fairly late in the novel, as a
clue in another problem.
Ari and Justin are back in the safe laboratory environment of Reseune,
safe now that politics are not trying to kill or control them. Yanni has
taken over administration. There is a general truce, and even some deeper
agreement. Everyone can take a breath and relax, albeit with the presence
of Justin's father Jordan as an ongoing irritant. But broader Union
politics are not stable: there is an election in progress for the Defense
councilor that may break the tenuous majority in favor of Reseune and the
Science Directorate, and Yanni is working out a compromise to gain more
support by turning a terraforming project loose on a remote world. As the
election and the politics heat up, interpersonal relationships abruptly
deteriorate, tensions with Jordan sharply worsen, and there may be moles
in Reseune's iron-clad security. Navigating the crisis while keeping her
chosen family safe will once again tax all of Ari's abilities.
The third section of Cyteen, where Ari finally has the tools to
take fate into her own hands and starts playing everyone off against each
other, is one of my favorite sections of any book. If it was yours as
well, Regenesis is another 700 pages of exactly that. As an
extension and revisiting, it does lose a bit of immediacy and surprise
from the original. Regenesis is also less concerned with the larger
questions of azi society, the nature of thought and personality, loyalty
and authority, and the best model for the development of human
civilization. It's more of a political thriller. But it's a political
thriller that recaptures much of the drama and tension of Cyteen
and is full of exceptionally smart and paranoid people thinking through
all angles of a problem, working fast on their feet, and successfully
navigating tricky and treacherous political landscapes.
And, like Cyteen but unlike others of Cherryh's novels I've read,
it's a novel about empowerment, about seizing control of one's
surroundings and effectively using all of the capability and leverage at
one's fingertips. That gives it a catharsis that's almost as good as
Cyteen.
It's also, like its predecessor, a surprisingly authoritarian novel. I
think it's in that, more than anything else in these books, that one sees
the impact of the azi. Regenesis makes it clear that the story is
set, not in a typical society, but inside a sort of corporation, with an
essentially hierarchical governance structure. There are other SF novels
set within corporations (Solitaire comes
to mind), but normally they follow peons or at best mid-level personnel or
field agents, or otherwise take the viewpoint of the employees or the
exploited. When they follow the corporate leaders, the focus usually isn't
down inside the organization, but out into the world, with the corporation
as silent resources on which the protagonist can draw.
Regenesis is instead about the leadership. It's about decisions
about the future of humanity that characters feel they can make
undemocratically (in part because they or their predecessors have
effectively engineered the opinions of the democratic population), but
it's also about how one manages and secures a top-down organization.
Reseune is, as in the previous novel, a paranoid's suspicions come true;
everyone is out to get everyone else, or at least might be, and the level
of omnipresent security and threat forces a close parsing of alliances and
motivations that elevates loyalty to the greatest virtue.
In Cyteen, we had long enough with Ari to see the basic shape of
her personality and her slight divergences from her predecessor, but her
actions are mostly driven by necessity. Regenesis gives us more of
a picture of what she's like when her actions aren't forced, and here I
think Cherryh manages a masterpiece of subtle characterization. Ari has
diverged substantially from her predecessor without always realizing, and
those divergences are firmly grounded in the differences she found or
created between her life and the first Ari's. She has friends, confidents,
and a community, which combined with past trauma has made her fiercely,
powerfully protective. It's that protective instinct that weaves the plot
together. So many of the events of Cyteen and Regenesis are
driven by people's varying reactions to trauma.
If you, like me, loved the last third of Cyteen, read this, because
Regenesis is more of exactly that. Cherryh finds new politics, new
challenges, and a new and original plot within the same world and with the
same characters, but it has the same feel of maneuvering, analysis, and
decisive action. You will, as with Cyteen have to be comfortable
with pages of internal monologue from people thinking through all sides of
a problem. If you didn't like that in the previous book, avoid this one;
if you loved it, here's the sequel you didn't know you were waiting for.
Original rating: 9 out of 10
Some additional thoughts after re-reading
Regenesis in 2025:
Cyteen mostly held up to a re-reading and I had fond memories of
Regenesis and hoped that it would as well. Unfortunately, it did
not. I think I can see the shape of what I enjoyed the first time I read
it, but I apparently was in precisely the right mood for this specific
type of political power fantasy.
I did at least say that you have to be comfortable with pages of internal
monologue, but on re-reading, there was considerably more of that than I
remembered and it was quite repetitive. Ari spends most of the book
chasing her tail, going over and around and beside the same theories that
she'd already considered and worrying over the nuances of every position.
The last time around, I clearly enjoyed that; this time, I found it
exhausting and not very well-written. The political maneuvering is not
that deep; Ari just shows every minutia of her analysis.
Regenesis also has more about the big questions of how to design a
society and the role of the azi than I had remembered, but I'm not sure
those discussions reach any satisfying conclusions. The book puts a great
deal of effort into trying to convince the reader that Ari is capable of
designing sociological structures that will shape Union society for
generations to come through, mostly, manipulation of azi programming (deep
sets is the term used in the book). I didn't find this entirely convincing
the first time around, and I was even less convinced in this re-read.
Human societies are a wicked problem, and I don't find Cherryh's computer projections any more
convincing than Asimov's psychohistory.
Related, I am surprised, in retrospect, that the authoritarian
underpinnings of this book didn't bother me more on my first read. They
were blatantly obvious on the second read. This felt like something
Cherryh put into these books intentionally, and I think it's left
intentionally ambiguous whether the reader is supposed to agree with Ari's
goals and decisions, but I was much less in the mood on this re-read to
read about Ari making blatantly authoritarian decisions about the future
of society simply because she's smart and thinks she, unlike others, is
acting ethically. I say this even though I like Ari and mostly
enjoyed spending time in her head. But there is a deep fantasy of being
able to reprogram society at play here that looks a lot nastier from the
perspective of 2025 than apparently it did to me in 2012.
Florian and Catlin are still my favorite characters in the series, though.
I find it oddly satisfying to read about truly competent bodyguards,
although like all of the azi they sit in an (I think intentionally)
disturbing space of ambiguity between androids and human slaves.
The somewhat too frank sexuality from Cyteen is still present in
Regenesis, but I found it a bit less off-putting, mostly because
everyone is older. The authoritarian bent is stronger, since
Regenesis is the story of Ari consolidating power rather than the
underdog power struggle of Cyteen, and I had less tolerance for it
on this re-read.
The main problem with this book on re-read was that I bogged down about
halfway through and found excuses to do other things rather than finish
it. On the first read, I was apparently in precisely the right mood to
read about Ari building a fortified home for all of her friends; this
time, it felt like endless logistics and musings on interior decorating
that didn't advance the plot. Similarly, Justin and Grant's slow
absorption into Ari's orbit felt like a satisfying slow burn friendship in
my previous reading and this time felt touchy and repetitive.
I was one of the few avid defenders of Regenesis the first time I
read it, and sadly I've joined the general reaction on a re-read: This is
not a very good book. It's too long, chases its own tail a bit too much,
introduces a lot more authoritarianism and doesn't question it as directly
as I wanted, and gets even deeper into Cherryh's invented
pseudo-psychology than Cyteen. I have a high tolerance for the
endless discussions of azi deep sets and human flux thinking, and even I
got bored this time through.
On re-read, this book was nowhere near as good as I thought it was
originally, and I would only recommend it to people who loved
Cyteen and who really wanted a continuation of Ari's story, even if
it is flabby and not as well-written. I have normally been keeping the
rating of my first read of books, but I went back and lowered this one by
two points to ensure it didn't show as high on my list of recommendations.
Just a small thing: I’m going to turn down the very simple gitweb interface at
https://git.k1024.org/. Way back, I thought I should have a backup for GitHub,
but the decentralised Git model makes this not really needed, and gitweb is
actually pretty heavy, even if it is really bare-bones.
Practically, as small as that site was, it was fine before the LLM era. Since
then, I keep getting lots of traffic, as if these repositories which already
exist on GitHub hold critical training information… Thus, I finally got the
impetus to turn it down, for no actual loss. Keeping it would make sense only if
I were to change it into a proper forge, but that’s a different beast, in which
I have no interest (as a public service). So, down it goes.
I’ll probably replace all of it with a single static page, text-only even 😄
Next in terms of simplification will probably be removing series from this blog,
since there’s not enough clear separation between tags and series. Or at least,
I’m not consequent enough to write a very clean set of articles that can be
ordered and numbered as a unit.
I’ve noticed that procrastination and inability to be consistently productive at work has become quite common in recent years. This is clearly visible in younger people who have grown up with an endless stream of entertainment literally at their fingertips, on their mobile phone. It is however a trap one can escape from with a little bit of help.
Procrastination is natural — they say humans are lazy by nature after all. Probably all of us have had moments when we choose to postpone a task we know we should be working on, and instead spent our time doing secondary tasks (valorisation). Classic example is cleaning your apartment when you should be preparing for an exam. Some may procrastinate by not doing any work at all, and just watching YouTube videos or the like. To some people, typically those who are in their 20s and early in their career, procrastination can be a big challenge and finding the discipline to stick to planned work may need intentional extra effort, and perhaps even external help.
During my 20+ year career in software development I’ve been blessed to work with engineers of various backgrounds and each with their unique set of strengths. I have also helped many grow in various areas and overcome challenges, such as lack of intrinsic motivation and managing procrastination, and some might be able to get it in check with some simple advice.
Distance yourself from the digital distractions
The key to avoiding distractions and procrastination is to make it inconvenient enough that you rarely do it. If continuing to do work is easier than switching to procrastination, work is more likely to continue.
Tips to minimize digital distractions, listed in order of importance:
Put your phone away. Just like when you go to a movie and turn off your phone for two hours, you can put the phone away completely when starting to work. Put the phone in a different room to ensure there is enough physical distance between you and the distraction, so it is impossible for you to just take a “quick peek”.
Turn off notifications from apps. Don’t let the apps call you like sirens luring Odysseus. You don’t need to have all the notifications. You will see what the apps have when you eventually open them at a time you choose to use them.
Remove or disable social media apps, games and the like from your phone and your computer. You can install them back when you have vacation. You can probably live without them for some time. If you can’t remove them, explore your phone’s screen time restriction features to limit your own access to apps that most often waste your time. These features are sometimes listed in the phone settings under “digital health”.
Have a separate work computer and work phone. Having dedicated ones just for work that are void of all unnecessary temptations helps keep distance from the devices that could derail your focus.
Listen to music. If you feel your brain needs a dose of dopamine to get you going, listening to music helps satisfy your brain’s cravings while still being able to simultaneously keep working.
Doing a full digital detox is probably not practical, or not sustainable for an extended time. One needs apps to stay in touch with friends and family, and staying current in software development probably requires spending some time reading news online and such. However the tips above can help contain the distractions and minimize the spontaneous attention the distractions get.
Some of the distractions may ironically be from the work itself, for example Slack notifications or new email notifications. I recommend turning them off for a couple of hours every day to have some distraction free time. It should be enough to check work mail a couple times a day. Checking them every hour probably does not add much overall value for the company unless your work is in sales or support where the main task itself is responding to emails.
Distraction free work environment
Following the same principle of distancing yourself from distractions, try to use a dedicated physical space for working. If you don’t have a spare room to dedicate to work, use a neighborhood café or sign up for a local co-working space or start commuting to the company office to find a space to be focused on work in.
Break down tasks into smaller steps
Sometimes people postpone tasks because they feel intimidated by the size or complexity of a task. In particular in software engineering problems may be vague and appear large until one reaches the breakthrough that brings the vision of how to tackle it. Breaking down problems into smaller more manageable pieces has many advantages in software engineering. Not only can it help with task-avoidance, but it can also make the problem easier to analyze, suggest solutions and test them and build a solid foundation to expand upon to ultimately later reach a full solution on the entire larger problem.
Working on big problems as a chain of smaller tasks may also offer more opportunities to celebrate success on completing each subtask and help getting in a suitable cadence of solving a single thing, taking a break and then tackling the next issue.
Breaking down a task into concrete steps may also help with getting more realistic time estimations. Sometimes procrastination isn’t real — someone could just be overly ambitious and feel bad about themselves for not doing an unrealistic amount of work.
Intrinsic motivation
Of course, you should follow your passion when possible. Strive to pick a career that you enjoy, and thus maximize the intrinsic motivation you experience. However, even a dream job is still a job. Nobody is ever paid to do whatever they want. Any work will include at least some tasks that feel like a chore or otherwise like something you would not do unless paid to.
Some would say that the definition of work itself is having to do things one would otherwise not do. You can only fully do whatever you want while on vacation or when you choose to not have a job at all. But if you have a job, you simply need to find the intrinsic motivation to do it.
Simply put, some tasks are just unpleasant or boring. Our natural inclination is to avoid them in favor of more enjoyable activities. For these situations we just have to find the discipline to force ourselves to do the tasks and figuratively speaking whip ourselves into being motivated to complete the tasks.
Extrinsic motivation
As the name implies, this is something people external to you need to provide, such as your employer or manager. If you have challenges in managing yourself and delivering results on a regular basis, somebody else needs to set goals and deadlines and keep you accountable for them. At the end of the day this means that eventually you will stop receiving salary or other payments unless you did your job.
Forcing people to do something isn’t nice, but eventually it needs to be done. It would not be fair for an employer to pay those who did their work the same salary as those who procrastinated and fell short on their tasks.
If you work solo, you can also simulate the extrinsic motivation by publicly announcing milestones and deadlines to build up pressure for yourself to meet them and avoid publicly humiliation. It is a well-studied and scientifically proven phenomenon that most university students procrastinate at the start of assignments, and truly start working on them only once the deadline is imminent.
External help for addictions
If procrastination is mainly due to a single distraction that is always on your mind, it may be a sign of an addiction. For example, constantly thinking about a computer game or staying up late playing a computer game, to the extent that it seriously affects your ability to work, may be a symptom of an addiction, and getting out of it may be easier with external help.
Discipline and structure
Most of the time procrastination is not due to an addiction, but simply due to lack of self-discipline and structure. The good thing is that those things can be learned. It is mostly a matter of getting into new habits, which most young software engineers pick up more or less automatically while working along the more senior ones.
Hopefully these tips can help you stay on track and ensure you do everything you are expected to do with clear focus, and on time!
I needed to bruteforce some passwords that I happened to know that were
generated with the default mode (“pronouncable”) of
pwgen, so I spent a fair amount of time
writing software to help. It went through a whole lot of iterations
and ended up being more efficient than I had ever assumed would be possible
(although it's still nowhere near as efficient as it should ideally be).
So now I'm sharing it with you. If you have IPv6 and can reach
git.sesse.net, that is.
I'm pasting the entire README below. Remember to use it for ethical
purposes.
Introduction
============
pwbrute creates all possible pwgen passwords (default tty settings, no -s).
It matches pwgen 2.08. It supports ordering them by most common first.
Note that pwgen before 2.07 also supported a special “non-tty mode”
that was even less secure (no digits, no uppercase) which is not supported here.
To get started, do
g++ -std=c++20 -O2 -o pwbrute pwbrute.cc -ljemalloc
./pwbrute --raw --sort --expand --verbose > passwords.txt
wait for an hour or two and you're left with 276B passwords in order
(about 2.5TB). (You can run without -ljemalloc, but the glibc malloc
makes pwbrute take about 50% more time.)
pwbrute is not a finished, polished product. Do not expect this to be
suitable for inclusion in e.g. a Linux distribution.
A brief exposition of pwgen's security
======================================
pwgen is a program that is fairly widely used in Linux/UNIX systems
to generate “pronounceable” (and thus supposedly easier-to-remember)
passwords. On the surface of it, the default 8-letter passwords with
uppercase letters, lowercase letters and digits would have a password
space of
62^8 = 218,340,105,584,896 ~= 47.63 bits
This isn't enough to save you from password cracking against fast hashes
(e.g. NTLM), but it's enough for almost everything else.
However, pwgen (without -s) does by design not use this entire space.
It builds passwords from a list of 40 “phonemes” (a, ae, ah, ai, b,
c, ch, ...) in sequence, with some rules of which can come after each
others (e.g. the combination f-g is disallowed, since any consonant
phoneme must be followed by a vowel or sometimes a digit), and sometimes
digits. Furthermore, some phonemes may be uppercased (only first letter,
in case of two-letter phonemes). In all, these restrictions mean that
the number of producable passwords drop to
307,131,320,668 ~= 38.16 bits
Furthermore, if a password does not contain at least one uppercase letter
and one digit, it is rejected. This doesn't affect that many passwords,
but it's still down to
276,612,845,450 ~= 38.00 bits
You would believe that this means that to get to a 50% chance of cracking
a password, you'd need to test about ~138 billon passwords; however, the
effective entropy is much, much worse than that:
First, consider that digits are inserted (at valid points) only with
30% probability, and phonemes are uppercased (at valid points) only
with 20% probability. This means that a password like “Ahdaiy7i” is
_much_ more likely than e.g. “EXuL8OhP” (five uppercase letters),
even though both are possible to generate.
Furthermore, when building up the password from left to right, every
letter is not equally likely -- every _phoneme_ is equally likely.
Since at any given point, (e.g.) “ai” is as likely as “a”, a lot fewer
rolls of the dice are required to get to eight letters if the password
contains many dipthongs (two-letter phonemes). This makes them vastly
overrepresented. E.g., the specific password “aechae0A” has three dipthongs
and a probability of about 1 in 12 million of being generated, while
“Oozaey7Y” has only two dipthongs (but an extra capital letter) and a
probability of about 1 in 9.33 _billion_!
In all, this means that to get to 50% probability of cracking a given
pwgen password (assuming you know that it was indeed generated with
pwgen, without -s), you need to test about 405 million passwords.
Note that pwgen gives out a list of passwords and lets the user choose,
which may make this easier or harder; I've had real-world single-password
cracks that fell after only ~400k attempts (~2% probability if the user
has chosen at random, but they most likely picked one that looked more
beautiful to them somehow).
This is all known; I reported the limited keyspace in 2004 (Debian bug
#276976), and Solar Designer reported the poor entropy in CVE-2013-4441.
(I discovered the entropy issues independently from them a couple of
months later, then discovered that it was already known, and didn't
publish.) However, to the best of my knowledge, pwbrute is the first
public program that will actually generate the most likely passwords
efficiently for you.
Needless to say, I cannot recommend using pwgen's phoneme-based
passwords for anything that needs to stay secure. (I will not make
concrete recommendations beyond that; a lot of literature exists
on the subject.)
Speeding up things
==================
Very few users would want the entire set of passwords, given that the
later ones are incredibly unlikely (e.g., AB0AB0AB has a chance of about
2^-52.155, or 1 in 5 quadrillion). To not get all, you can use e.g.
-c -40, which will produce only those with more than approx. 2^-40 probability
before final rejection (roughly ~6B passwords).
(NOTE: Since the calculated probability is before final rejection of those
without a digit or uppercase letter, they will not sum to 1, but something
less; approx. 0.386637 for the default 8-letter passwords, or 2^-1.3709.
Take this into account when reading all text below.)
pwbrute is fast but not super-fast; it can generate about 80M passwords/sec
(~700 MB/sec) to stdout, of course depending on your CPUs. The expansion phase
generally takes nearly all the time; if your cracker could somehow accept the
unexpanded patterns (i.e., without --expand) for free, pwbrute would basically
be infinitely fast. (It would be possible to microoptimize the expansion,
perhaps to 1B passwords/sec/core if pulling out all the stops, but at some point,
it starts becoming a problem related to pipe I/O performance, not candidate
generation.)
Thus, if your cracker is very fast (e.g. hashcat cracking NTLM), it's suboptimal
to try to limit yourself to only pwbrute-created passwords. It's much, much
faster to just create a bunch of legal prefixes and then let hashcat try all
of them, even though this will test some “impossible” passwords.
For instance:
./pwbrute --first-stage-len 5 --raw > start5.pwd
./hashcat.bin -O -m 1000 ntlm.pwd -w 3 -a 6 start5.pwd -1 '?l?u?d' '?1?1?1'
The “combination” mode in hashcat is also not always ideal; consider using
rules instead.
If you need longer passwords than 8 characters, you may want to split the job
into multiple parts. For this, you can combine --first-stage-len with --prefix
to generate passwords in two stages, e.g. first generate all valid 3-letter
prefixes (“bah” is valid, “bbh” is not) and then for each prefix generate
all possible passwords. This requires much less RAM, can go in parallel,
and is pretty efficient.
For instance, this will create all passwords up to probability 2^-30,
over 16 cores, in a form that doesn't use too much RAM:
./pwbrute -f 3 -r -s -e | parallel -j 16 "./pwbrute -p {} -c -30 -s 2>/dev/null | zstd -6 > up-to-30-{}.pwd.zst"
You can then use the included merge.cc utility to merge the sorted files
into a new sorted one (this requires not using pwbrute --raw, since merge
wants the probabilities to merge correctly):
g++ -O2 -o merge merge.cc -lzstd
./merge up-to-30-*.pwd.zst | pv | pzstd -6 > up-to-30.pwd.zst
merge is fairly fast, but not infinitely so. Sorry.
Beware, zstd uses some decompression buffers that can be pretty big per-file
and there are lots of files, so if you put the limit lower than -30,
consider merging in multiple phases or giving -M to zstd, unless you want to
say hello to the OOM killer half-way into your merge.
As long as you give the --sort option to pwbrute, it is designed to give exactly
the same output in the same order every time (at the expense of a little bit of
speed during the pattern generation phase). This means that you can safely resume
an aborted generation or cracking job using the --skip=NUM flag, without worrying
that you'd lose some candidates.
Here are some estimated numbers for various probability cutoffs, and how much
of the probability space they cover (after correction for rejected passwords):
p >= 2^-25: 78,000 passwords ( 0.00% coverage, 0.63% probability)
p >= 2^-26: 171,200 passwords ( 0.00% coverage, 1.12% probability)
p >= 2^-27: 3,427,100 passwords ( 0.00% coverage, 9.35% probability)
p >= 2^-28: 5,205,200 passwords ( 0.00% coverage, 12.01% probability)
p >= 2^-29: 8,588,250 passwords ( 0.00% coverage, 14.17% probability)
p >= 2^-30: 24,576,550 passwords ( 0.01% coverage, 19.23% probability)
p >= 2^-31: 75,155,930 passwords ( 0.03% coverage, 27.58% probability)
p >= 2^-32: 284,778,250 passwords ( 0.10% coverage, 43.81% probability)
p >= 2^-33: 540,418,450 passwords ( 0.20% coverage, 55.14% probability)
p >= 2^-34: 808,534,920 passwords ( 0.29% coverage, 60.49% probability)
p >= 2^-35: 1,363,264,200 passwords ( 0.49% coverage, 66.28% probability)
p >= 2^-36: 2,534,422,340 passwords ( 0.92% coverage, 72.36% probability)
p >= 2^-37: 5,663,431,890 passwords ( 2.05% coverage, 80.54% probability)
p >= 2^-38: 11,178,389,760 passwords ( 4.04% coverage, 87.75% probability)
p >= 2^-39: 16,747,555,070 passwords ( 6.05% coverage, 91.55% probability)
p >= 2^-40: 25,139,913,440 passwords ( 9.09% coverage, 94.25% probability)
p >= 2^-41: 34,801,107,110 passwords ( 12.58% coverage, 95.91% probability)
p >= 2^-42: 52,374,739,350 passwords ( 18.93% coverage, 97.38% probability)
p >= 2^-43: 78,278,619,550 passwords ( 28.30% coverage, 98.51% probability)
p >= 2^-44: 111,967,613,850 passwords ( 40.48% coverage, 99.25% probability)
p >= 2^-45: 147,452,759,450 passwords ( 53.31% coverage, 99.64% probability)
p >= 2^-46: 186,012,691,450 passwords ( 67.25% coverage, 99.86% probability)
p >= 2^-47: 215,059,885,450 passwords ( 77.75% coverage, 99.94% probability)
p >= 2^-48: 242,726,285,450 passwords ( 87.75% coverage, 99.98% probability)
p >= 2^-49: 257,536,845,450 passwords ( 93.10% coverage, 99.99% probability)
p >= 2^-50: 268,815,845,450 passwords ( 97.18% coverage, 100.00% probability)
p >= 2^-51: 273,562,845,450 passwords ( 98.90% coverage, 100.00% probability)
p >= 2^-52: 275,712,845,450 passwords ( 99.67% coverage, 100.00% probability)
p >= 2^-53: 276,512,845,450 passwords ( 99.96% coverage, 100.00% probability)
all: 276,612,845,450 passwords (100.00% coverage, 100.00% probability)
License
=======
pwbrute is Copyright (C) 2025 Steinar H. Gunderson.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
On the 8th of August 2025 (a day before the Debian Trixie release), I was upgrading my personal laptop from Debian Bookworm to Trixie. It was a major update. However, the update didn’t go smoothly, and I ran into some errors. From the Debian support IRC channel, I got to know that it would be best if I removed the texlive packages.
However, it was not so easy to just remove texlive with a simple apt remove command. I had to remove the texlive packages from /usr/bin. Then I ran into other errors. Hours after I started the upgrade, I realized I preferred having my system as it was before, as I had to travel to Noida the next day. Needless to say, I wanted to go to sleep rather than fix my broken system. Only if I had a way to go back to my system before I started upgrading, it would have saved a lot of trouble for me. I ended up installing Trixie from scratch.
It turns out that there was a way to recover to the state before the upgrade - using Timeshift to roll back the system to a state (in our example, it is the state before the upgrade process started) in the past. However, it needs the Btrfs filesystem with appropriate subvolumes, not provided by Debian installer in their guided partitioning menu.
I have set it up after a few weeks of the above-mentioned incident. Let me demonstrate how it works.
Check the screenshot above. It shows a list of snapshots made by Timeshift. Some of them were made by me manually. Others were made by Timeshift automatically as per the routine - I have set up hourly backups and weekly backups etc.
In the above-mentioned major update, I could have just taken a snapshot using Timeshift before performing the upgrade and could have rolled back to that snapshot when I found that I cannot spend more time on fixing my installation errors. Then I could just perform the upgrade later.
Installation
In this tutorial, I will cover how I installed Debian with Btrfs and disk encryption, along with creating subvolumes @ for root and @home for /home so that I can use Timeshift to create snapshots. These snapshots are kept on the same disk where Debian is installed, and the use-case is to roll back to a working system in case I mess up something or to recover an accidentally deleted file.
I went through countless tutorials on the Internet, but I didn’t find a single tutorial covering both the disk encryption and the above-mentioned subvolumes (on Debian). Debian doesn’t create the desired subvolumes by default, therefore the process requires some manual steps, which beginners may not be comfortable performing. Beginners can try distros such as Fedora and Linux Mint, as their installation includes Btrfs with the required subvolumes.
Furthermore, it is pertinent to note that I used Debian Trixie’s DVD iso on a real laptop (not a virtual machine) for my installation. Debian Trixie is the codename for the current stable version of Debian. Then I took screenshots in a virtual machine by repeating the process. Moreover, a couple of screenshots are from the installation I did on the real laptop.
Let’s start the tutorial by booting up the Debian installer.
The above screenshot shows the first screen we see on the installer. Since we want to choose Expert Install, we select Advanced Options in the screenshot above.
Let’s select the Expert Install option in the above screenshot. It is because we want to create subvolumes after the installer is done with the partition, and only then proceed to installing the base system. “Non-expert” install modes proceed directly to installing the system right after creating partitions without pausing for us to create the subvolumes.
After selecting the Expert Install option, you will get the screen above. I will skip to partitioning from here and leave the intermediate steps such as choosing language, region, connecting to Wi-Fi, etc. For your reference, I did create the root user.
Let’s jump right to the partitioning step. Select the Partition disks option from the menu as shown above.
Choose Manual.
Select your disk where you would like to install Debian.
Select Yes when asked for creating a new partition.
I chose the msdos option as I am not using UEFI. If you are using UEFI, then you need to choose the gpt option. Also, your steps will (slightly) differ from mine if you are using UEFI. In that case, you can watch this video by the YouTube channel EF Linux in which he creates an EFI partition. As he doesn’t cover disk encryption, you can continue reading this post after following the steps corresponding to EFI.
Select the free space option as shown above.
Choose Create a new partition.
I chose the partition size to be 1 GB.
Choose Primary.
Choose Beginning.
Now, I got to this screen.
I changed mount point to /boot and turned on the bootable flag and then selected “Done setting up the partition.”
Now select free space.
Choose the Create a new partition option.
I made the partition size equal to the remaining space on my disk. I do not intend to create a swap partition, so I do not need more space.
Select Primary.
Select the Use as option to change its value.
Select “physical volume for encryption.”
Select Done setting up the partition.
Now select “Configure encrypted volumes.”
Select Yes.
Select Finish.
Selecting Yes will take a lot of time to erase the data. Therefore, I would say if you have hours for this step (in case your SSD is like 1 TB), then I would recommend selecting “Yes.” Otherwise, you could select “No” and compromise on the quality of encryption.
After this, you will be asked to enter a passphrase for disk encryption and confirm it. Please do so. I forgot to take the screenshot for that step.
Now select that encrypted volume as shown in the screenshot above.
Here we will change a couple of options which will be shown in the next screenshot.
In the Use as menu, select “btrfs journaling file system.”
Now, click on the mount point option.
Change it to “/ - the root file system.”
Select Done setting up the partition.
This is a preview of the paritioning after performing the above-mentioned steps.
If everything is okay, proceed with the Finish partitioning and write changes to disk option.
The installer is reminding us to create a swap partition. I proceeded without it as I planned to add swap after the installation.
If everything looks fine, choose “yes” for writing the changes to disks.
Now we are done with partitioning and we are shown the screen in the screenshot above. If we had not selected the Expert Install option, the installer would have proceeded to install the base system without asking us.
However, we want to create subvolumes before proceeding to install the base system. This is the reason we chose Expert Install.
Now press Ctrl + F2.
You will see the screen as in the above screenshot. It says “Please press Enter to activate this console.” So, let’s press Enter.
After pressing Enter, we see the above screen.
The screenshot above shows the steps I performed in the console. I followed the already mentioned video by EF Linux for this part and adapted it to my situation (he doesn’t encrypt the disk in his tutorial).
First we run df -h to have a look at how our disk is partitioned. In my case, the output was:
df -h shows us that /dev/mapper/sda2_crypt and /dev/sda1 are mounted on /target and /target/boot respectively.
Let’s unmount them. For that, we run:
# umount /target
# umount /target/boot
Next, let’s mount our root filesystem to /mnt.
# mount /dev/mapper/sda2_crypt /mnt
Let’s go into the /mnt directory.
# cd /mnt
Upon listing the contents of this directory, we get:
/mnt # ls
@rootfs
Debian installer has created a subvolume @rootfs automatically. However, we need the subvolumes to be @ and @home. Therefore, let’s rename the @rootfs subvolume to @.
/mnt # mv @rootfs @
Listing the contents of the directory again, we get:
/mnt # ls
@
We only one subvolume right now. Therefore, let us go ahead and create another subvolume @home.
If we perform ls now, we will see there are two subvolumes:
/mnt # ls
@ @home
Let us mount /dev/mapper/sda2_crypt to /target
/mnt # mount -o noatime,space_cache=v2,compress=zstd,ssd,discard=async,subvol=@ /dev/mapper/sda2_crypt /target/
Now we need to create a directory for /home.
/mnt # mkdir /target/home/
Now we mount the /home directory with subvol=@home option.
/mnt # mount -o noatime,space_cache=v2,compress=zstd,ssd,discard=async,subvol=@home /dev/mapper/sda2_crypt /target/home/
Now mount /dev/sda1 to /target/boot.
/mnt # mount /dev/sda1 /target/boot/
Now we need to add these options to the fstab file, which is located at /target/etc/fstab. Unfortunately, vim is not installed in this console. The only way to edit is Nano.
nano /target/etc/fstab
Edit your fstab file to look similar to the one in the screenshot above. I am pasting the fstab file contents below for easy reference.
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# systemd generates mount units based on this file, see systemd.mount(5).
# Please run 'systemctl daemon-reload' after making changes here.
#
# <file system> <mount point> <type> <options> <dump> <pass>
/dev/mapper/sda2_crypt / btrfs noatime,compress=zstd,ssd,discard=async,space_cache=v2,subvol=@ 0 0
/dev/mapper/sda2_crypt /home btrfs noatime,compress=zstd,ssd,discard=async,space_cache=v2,subvol=@home 0 0
# /boot was on /dev/sda1 during installation
UUID=12842b16-d3b3-44b4-878a-beb1e6362fbc /boot ext4 defaults 0 2
/dev/sr0 /media/cdrom0 udf,iso9660 user,noauto 0 0
Please double check the fstab file before saving it. In Nano, you can press Ctrl+O followed by pressing Enter to save the file. Then press Ctrl+X to quit Nano. Now, preview the fstab file by running
cat /target/etc/fstab
and verify that the entries are correct, otherwise you will booted to an unusable and broken system after the installation is complete.
Next, press Ctrl + Alt + F1 to go back to the installer.
Proceed to “Install the base system.”
Screenshot of Debian installer installing the base system.
I chose the default option here - linux-image-amd64.
After this, the installer will ask you a few more questions. For desktop environment, I chose KDE Plasma. You can choose the desktop environment as per your liking. I will not cover the rest of the installation process and assume that you were able to install from here.
Post installation
Let’s jump to our freshly installed Debian system. Since I created a root user, I added the user ravi to the suoders file (/etc/sudoers) so that ravi can run commands with sudo. Follow this if you would like to do the same.
Now we set up zram as swap. First, install zram-tools.
sudo apt install zram-tools
Now edit the file /etc/default/zramswap and make sure to have the following lines are uncommented:
ALGO=lz4
PERCENT=50
Now, run
sudo systemctl restart zramswap
If you run lsblk now, you should see the below-mentioned entry in the output:
zram0 253:0 0 7.8G 0 disk [SWAP]
This shows us that zram has been activated as swap.
Now we install timeshift, which can be done by running
sudo apt install timeshift
After the installation is complete, run Timeshift and schedule snapshots as you please. We are done now. Hope the tutorial was helpful.
See you in the next post and let me know if you have any suggestions and questions on this tutorial.
I have been using my Samsung Galaxy Tab A (2015) with PostmarketOS on and off since last year. It serves as a really good e-book reader with KOReader installed on it.
Have tried phosh and plasma-mobile on it, works nicely but slows the device down heavily (2 GB RAM and old processor) so I use MATE Desktop environment on it.
Lately I have started using this tablet along with my laptop as a second screen for work. And it has been working super nicely for that. The only issue being that I have to manually rotate the screen to landscape every time I reboot the device. It resets the screen orientation to portrait after a reboot. So I went through the pmOS wiki and a neat nice hack documented there worked very well for me.
First we will test if the auto-rotate sensor works and if we can read values from it. So we install some basic necessary packages
You need to replace the name of your touch input device in the script, you can get the name by using xinput --list , make sure to type this on the device terminal.
In our script here we are using a Zinitix capacitive screen, it will be different for yours.
Once your script is ready with the correct touchscreen name. Save and make the script executable. chmod +x auto-rotate-screen.sh
Then test your script in your terminal ./auto-rotate.sh , stop the script using Ctrl + C
Now we need add this script to auto-start. On MATE DE you can go to System > Control Center > Startup Applications, then click on Custom Add button, browse the script location, give it a name and then click on Add button.
Now reboot the tablet/device, login and see the auto rotation working.
When a Debian cloud VM boots, it typically runs cloud-init at various points in the boot process. Each invocation can perform certain operations based on the host’s static configuration passed by the user, typically either through a well known link-local network service or an attached iso9660 drive image. Some of the cloud-init steps execute before the network comes up, and others at a couple of different points after the network is up.
I recently encountered an unexpected issue when configuring a dualstack (uses both IPv6 and legacy IPv4 networking) VM to use a custom apt server accessible only via IPv6. VM provisioning failed because it was unable to access the server in question, yet when I logged in to investigate, it was able to access the server without any problem. The boot had apparently gone smoothly right up until cloud-init’s Package Update Upgrade Install module called apt-get update, which failed and broke subsequent provisioning steps. The errors reported by apt-get indicated that there was no route to the service in question, which more accurately probably meant that there was not yet a route to the service. But there was shortly after, when I investigated.
This was surprising because the apt-get invocations occur in a cloud-init sequence that’s explicitly ordered after the network is configured according to systemd-networkd-wait-online. Investigation eventually led to similar issues encountered in other environments reported in Debian bug #1111791, “systemd: network-online.target reached before IPv6 address is ready”. The issue described in that bug is identical to mine, but the bug is tagged wontfix. The behavior is considered correct.
Why the default behavior is the correct one
While it’s a bit counterintuitive, the systemd-networkd behavior is correct, and it’s also not something we’d want to override in the cloud images. Without explicit configuration, systemd can’t accurately infer the intended network configuration of a given system. If a system is IPv6-only, systemd-networkd-wait-online will introduce unexpected delays in the boot process if it waits for IPv4, and vice-versa. If it assumes dualstack, things are even worse because it would block for a long time (approximately two minutes) in any single stack network before failing, leaving the host in degraded state. So the most reasonable default behavior is to block until any protocol is configured.
For these same reasons, we can’t change the systemd-networkd-wait-online configuration in our cloud images. All of the cloud environments we support offer both single stack and dual stack networking, so we preserve systemd’s default behavior.
What’s causing problems here is that IPv6 takes significantly longer to configure due to its more complex router solicitation + router advertisement + DHCPv6 setup process. So in this particular case, where I’ve got a dualstack VM that needs to access a v6-only apt server during the provisioning process, I need to find some mechanism to override systemd’s default behavior and wait for IPv6 connectivity specifically.
What won’t work
Cloud-init offers the ability to write out arbitrary files during provisioning. So writing a drop-in for systemd-networkd-wait-online.service is trivial. Unfortunately, this doesn’t give us everything we actually need. We still need to invoke systemctl daemon-reload to get systemd to actually apply the changes after we’ve written them, and of course we need to do that before the service actually runs. Cloud-init provides a bootcmd module that lets us run shell commands “very early in the boot process”, but it runs too early: it runs before we’ve written out our configuration files. Similarly, it provides a runcmd module, but scripts there are towards the end of the boot process, far too late to be useful.
Instead of using the bootcmd facility, to simply reload systemd’s config, it seemed possible that we could both write the config and trigger the reload, similar to the following:
But even that runs too late, as we can see in the logs that systemd-networkd-wait-online.service has completed before bootcmd is executed:
root@sid-tmp2:~# journalctl --no-pager -l -u systemd-networkd-wait-online.service
Aug 29 17:02:12 sid-tmp2 systemd[1]: Starting systemd-networkd-wait-online.service - Wait for Network to be Configured...
Aug 29 17:02:13 sid-tmp2 systemd[1]: Finished systemd-networkd-wait-online.service - Wait for Network to be Configured
.
root@sid-tmp2:~# grep -F 'config-bootcmd ran' /var/log/cloud-init.log
2025-08-29 17:02:14,766 - handlers.py[DEBUG]: finish: init-network/config-bootcmd: SUCCESS: config-bootcmd ran successfully and took 0.467 seconds
At this point, it’s looking like there are few options left!
What eventually worked
I ended up identifying two solutions to the issue, both of which involve getting some other component of the provisioning process to run systemd-networkd-wait-online.
Solution 1
The first involves getting apt-get itself to wait for IPv6 configuration. The apt.conf configuration interface allows the definition of an APT::Update::Pre-Invoke hook that’s executed just before apt’s update operation. By writing the following to a file in /etc/apt/apt.conf.d/, we’re able to ensure that we have IPv6 connectivity before apt-get tries accessing the network. This cloud-config snippet accomplishes that:
This is safe to leave in place after provisioning, because the delay will be negligible once IPv6 connectivity is established. It’s only during address configuration that it’ll block for a noticeable amount of time, but that’s what we want.
This solution isn’t entirely correct, though, because it’s only apt-get that’s actually affected by it. Other service that start after the system is ostensibly “online” might only see IPv4 connectivity when they start. This seems acceptable at the moment, though.
Solution 2
The second solution is to simply invoke systemd-networkd-wait-online directly from a cloud-init bootcmd. Similar to the first solution, it’s not exactly correct because the host has already reached network-online.target, but it does block enough of cloud-init that package installation happens only after it completes. The cloud-config snippet for this is
In either case, we still want to write out a snippet to configure systemd-networkd-wait-online to wait for IPv6 connectivity for future reboots. Even though cloud-init won’t necessarily run in those cases, and many cloud VMs never reboot at all, it does complete the solution. Additionally, it solves the problem for any derivative images that may be created based on the running VM’s state. (At least if we can be certain that instances of those derivative images will never run in an IPv4-only network!)
One possible improvement would be for cloud-init to support a configuration key allowing the admin to specify the required protocols. Based on the presence of this key, cloud-init could reconfigure systemd-networkd-wait-online.service accordingly. Alternatively it could set the appropriate RequiredFamilyForOnline= value in the generated .network file. cloud-init supports multiple network configuration backends, so each of those would need to be updated. If using the systemd-networkd configuration renderer, this should be straightforward, but Debian uses the netplan renderer, so that tool might also need to be taught to pass such a configuration along to systemd-networkd.
Every two years Debian releases a new major version of its Stable series,
meaning the differences between consecutive Debian Stable releases represent
two years of new developments both in Debian as an organization and its native
packages, but also in all other packages which are also shipped by other
distributions (which are getting into this new Stable release).
If you're not paying close attention to everything that's going on all the time
in the Linux world, you miss a lot of the nice new features and tools. It's
common for people to only realize there's a cool new trick available only years
after it was first introduced.
Given these considerations, the tips that I'm describing will eventually be
available in whatever other distribution you use, be it because it's a Debian
derivative or because it just got the same feature from the upstream project.
I'm not going to list "passive" features (as good as they can be), the focus
here is on new features that might change how you configure and use your
machine, with a mix between productivity and performance.
Debian 13 - Trixie
I have been a Debian Testing user for longer than 10 years now (and I recommend
it for non-server users), so I'm not usually keeping track of all the cool
features arriving in the new Stable releases because I'm continuously receiving
them through the Debian Testing rolling release.
Nonetheless, as a Debian Developer I'm in a good position to point out the ones
I can remember. I would also like other Debian Developers to do the same as I'm
sure I would learn something new.
The Debian 13 release notes contain a "What's new" section
, which
lists the first two items here and a few other things, in other words, take my
list as an addition to the release notes.
Debian 13 was released on 2025-08-09, and these are nice things you shouldn't
miss in the new release, with a bonus one not tied to the Debian 13 release.
1) wcurl
Have you ever had to download a file from your terminal using curl and didn't
remember the parameters needed? I did.
Nowadays you can use wcurl; "a command line tool which lets you download URLs
without having to remember any parameters."
Simply call wcurl with one or more URLs as parameters and it will download
all of them in parallel, performing retries, choosing the correct output file
name, following redirects, and more.
Try it out:
wcurl example.com
wcurl comes installed as part of the curl package on Debian 13 and in any other
distribution you can imagine, starting with curl 8.14.0.
I've written more about wcurl in its release
announcement
and I've done a lightning talk presentation in DebConf24, which is linked in
the release announcement.
2) HTTP/3 support in curl
Debian has become the first stable Linux distribution to ship curl with support
for HTTP/3. I've written about this in July
2024, when we
first enabled it. Note that we first switched the curl CLI to GnuTLS, but then
ended up releasing the curl CLI linked with OpenSSL (as support arrived later).
Debian was the first Linux distro to enable it in the default build of the curl
package, but Gentoo enabled it a few weeks earlier in their non-default flavor
of the package, kudos to them!
HTTP/3 is not used by default by the curl CLI, you have to enable it with
--http3 or --http3-only.
Starting with systemd v254, there's a new soft-reboot option, it's an
userspace-only reboot, much faster than a full reboot if you don't need to
reboot the kernel.
I love this, but it's still not yet where it should be, fingers crossed for a
simple apt upgrade to behave like other package managers by updating its
cache as part of the task, maybe in Debian 14?
Try it out:
sudo apt upgrade --update# The order doesn't mattersudo apt --update upgrade
This is especially handy for container usage, where you have to update the apt
cache before installing anything, for example:
podman run debian:stable bin/bash -c'apt install --update -y curl'
5) powerline-go
powerline-go is a powerline-style prompt written in Golang, so it's much more
performant than its Python alternative powerline.
powerline-style prompts are quite useful to show things like the current status
of the git repo in your working directory, exit code of the previous command,
presence of jobs in the background, whether or not you're in an ssh session,
and more.
Try it out:
sudo apt install powerline-go
Then add this to your .bashrc:
function_update_ps1(){PS1="$(/usr/bin/powerline-go -error$? -jobs$(jobs -p|wc -l))"# Uncomment the following line to automatically clear errors after showing# them once. This not only clears the error for powerline-go, but also for# everything else you run in that shell. Don't enable this if you're not# sure this is what you want.#set "?"}if["$TERM"!="linux"]&&[-f"/usr/bin/powerline-go"];thenPROMPT_COMMAND="_update_ps1; $PROMPT_COMMAND"fi
Or this to .zshrc:
functionpowerline_precmd(){PS1="$(/usr/bin/powerline-go -error$? -jobs${${(%):%j}:-0})"# Uncomment the following line to automatically clear errors after showing# them once. This not only clears the error for powerline-go, but also for# everything else you run in that shell. Don't enable this if you're not# sure this is what you want.#set "?"}
If you'd like to have your prompt start in a newline, like I have in the
screenshot above, you just need to set -newline in the powerline-go
invocation in your .bashrc/.zshrc.
6) Gnome System Monitor Extension
Tips number 6 and 7 are for Gnome users.
Gnome is now shipping a system monitor extension which lets you get a glance of
the current load of your machine from the top bar.
I've found this quite useful for machines where I'm required to install
third-party monitoring software that tends to randomly consume more resources
than it should. If I feel like my machine is struggling, I can quickly glance
at its load to verify if it's getting overloaded by some process.
The extension is not as complete as
system-monitor-next,
not showing temperatures or histograms, but at least it's officially part of
Gnome, easy to install and supported by them.
And then enable the extension from the "Extension Manager" application.
7) Gnome setting for battery charging profile
After having to learn more about batteries in order to get into FPV drones,
I've come to have a bigger appreciation for solutions that minimize the
inevitable loss of capacity that accrues over time.
There's now a "Battery Charging" setting (under the "Power") section which lets
you choose between two different profiles: "Maximize Charge" and "Preserve
Battery Health".
On supported laptops, this setting is an easy way to set thresholds for when
charging should start and stop, just like you could do it with the tlp package,
but now from the Gnome settings.
To increase the longevity of my laptop battery, I always keep it at "Preserve
Battery Health" unless I'm traveling.
What I would like to see next is support for choosing different "Power Modes"
based on whether the laptop is plugged-in, and based on the battery
charge percentage.
There's a GNOME
issue
tracking this feature, but there's some pushback on whether this is the right
thing to expose to users.
In the meantime, there are some workarounds mentioned in that issue which
people who really want this feature can follow.
If you would like to learn more about batteries; Battery
University is a great starting point, besides
getting into FPV drones and being forced to handle batteries without a Battery
Management System (BMS).
And if by any chance this sparks your interest in FPV drones, Joshua Bardwell's
YouTube channel is a great resource:
@JoshuaBardwell.
8) Lazygit
Emacs users are already familiar with the legendary magit; a terminal-based
UI for git.
Lazygit is an alternative for non-emacs users, you can integrate it with neovim
or just use it directly.
I'm still playing with lazygit and haven't integrated it into my workflows,
but so far it has been a pleasant experience.
And then call lazygit from within a git repository.
9) neovim
neovim has been shipped in Debian since 2016, but upstream has been doing a lot of
work to improve the experience out-of-the-box in the last couple of years.
If you're a neovim poweruser, you're likely not installing it from the official
repositories, but for those that are, Debian 13 comes with version 0.10.4,
which brings the following improvements compared to the version in Debian 12:
Treesitter support for C, Lua, Markdown, with the possibility of adding any
other languages as needed;
Better spellchecking due to treesitter integration (spellsitter);
Mouse support enabled by default;
Commenting support out-of-the-box;
Check :h commenting for details, but the
tl;dr is that you can use gcc to comment the current line and gc to comment
the current selection.
OSC52 support.
Especially handy for those using neovim over an ssh
connection, this protocol lets you copy something from within the neovim
process into the clipboard of the machine you're using to connect through ssh.
In other words, you can copy from neovim running in a host over ssh and paste
it in the "outside" machine.
10) [Bonus] Running old Debian releases
The bonus tip is not specific to the Debian 13 release, but something I've
recently learned in the #debian-devel IRC channel.
Did you know there are usable container images for all past Debian releases?
I'm not talking "past" as in "some of the older releases", I'm talking past as
in "literally every Debian release, including the very first one".
Tianon Gravi "tianon" is the Debian Developer responsible for making this
happen, kudos to him!
There's a small gotcha that the releases Buzz (1.1) and Rex (1.2) require a
32-bit host, otherwise you will get the error Out of virtual memory!, but
starting with Bo (1.3) all should work in amd64/arm64.
Try it out:
sudo apt install podmanpodman run -it docker.io/debian/eol:bo
Don't be surprised when noticing that apt/apt-get is not available inside the
container, that's because apt first appeared in Debian Slink (2.1).
Every two years Debian releases a new major version of its Stable series,
meaning the differences between consecutive Debian Stable releases represent
two years of new developments both in Debian as an organization and its native
packages, but also in all other packages which are also shipped by other
distributions (which are getting into this new Stable release).
If you're not paying close attention to everything that's going on all the time
in the Linux world, you miss a lot of the nice new features and tools. It's
common for people to only realize there's a cool new trick available only years
after it was first introduced.
Given these considerations, the tips that I'm describing will eventually be
available in whatever other distribution you use, be it because it's a Debian
derivative or because it just got the same feature from the upstream project.
I'm not going to list "passive" features (as good as they can be), the focus
here is on new features that might change how you configure and use your
machine, with a mix between productivity and performance.
Debian 13 - Trixie
I have been a Debian Testing user for longer than 10 years now (and I recommend
it for non-server users), so I'm not usually keeping track of all the cool
features arriving in the new Stable releases because I'm continuously receiving
them through the Debian Testing rolling release.
Nonetheless, as a Debian Developer I'm in a good position to point out the ones
I can remember. I would also like other Debian Developers to do the same as I'm
sure I would learn something new.
The Debian 13 release notes contain a "What's new" section
, which
lists the first two items here and a few other things, in other words, take my
list as an addition to the release notes.
Debian 13 was released on 2025-08-09, and these are nice things you shouldn't
miss in the new release, with a bonus one not tied to the Debian 13 release.
1) wcurl
Have you ever had to download a file from your terminal using curl and didn't
remember the parameters needed? I did.
Nowadays you can use wcurl; "a command line tool which lets you download URLs
without having to remember any parameters."
Simply call wcurl with one or more URLs as parameters and it will download
all of them in parallel, performing retries, choosing the correct output file
name, following redirects, and more.
Try it out:
wcurl example.com
wcurl comes installed as part of the curl package on Debian 13 and in any other
distribution you can imagine, starting with curl 8.14.0.
I've written more about wcurl in its release
announcement
and I've done a lightning talk presentation in DebConf24, which is linked in
the release announcement.
2) HTTP/3 support in curl
Debian has become the first stable Linux distribution to ship curl with support
for HTTP/3. I've written about this in July
2024, when we
first enabled it. Note that we first switched the curl CLI to GnuTLS, but then
ended up releasing the curl CLI linked with OpenSSL (as support arrived later).
Debian was the first stable Linux distro to enable it, and within
rolling-release-based distros; Gentoo enabled it first in their non-default
flavor of the package and Arch Linux did it three months before we pushed it to
Debian Unstable/Testing/Stable-backports, kudos to them!
HTTP/3 is not used by default by the curl CLI, you have to enable it with
--http3 or --http3-only.
Starting with systemd v254, there's a new soft-reboot option, it's an
userspace-only reboot, much faster than a full reboot if you don't need to
reboot the kernel.
I love this, but it's still not yet where it should be, fingers crossed for a
simple apt upgrade to behave like other package managers by updating its
cache as part of the task, maybe in Debian 14?
Try it out:
sudo apt upgrade --update# The order doesn't mattersudo apt --update upgrade
This is especially handy for container usage, where you have to update the apt
cache before installing anything, for example:
podman run debian:stable bin/bash -c'apt install --update -y curl'
5) powerline-go
powerline-go is a powerline-style prompt written in Golang, so it's much more
performant than its Python alternative powerline.
powerline-style prompts are quite useful to show things like the current status
of the git repo in your working directory, exit code of the previous command,
presence of jobs in the background, whether or not you're in an ssh session,
and more.
Try it out:
sudo apt install powerline-go
Then add this to your .bashrc:
function_update_ps1(){PS1="$(/usr/bin/powerline-go -error$? -jobs$(jobs -p|wc -l))"# Uncomment the following line to automatically clear errors after showing# them once. This not only clears the error for powerline-go, but also for# everything else you run in that shell. Don't enable this if you're not# sure this is what you want.#set "?"}if["$TERM"!="linux"]&&[-f"/usr/bin/powerline-go"];thenPROMPT_COMMAND="_update_ps1; $PROMPT_COMMAND"fi
Or this to .zshrc:
functionpowerline_precmd(){PS1="$(/usr/bin/powerline-go -error$? -jobs${${(%):%j}:-0})"# Uncomment the following line to automatically clear errors after showing# them once. This not only clears the error for powerline-go, but also for# everything else you run in that shell. Don't enable this if you're not# sure this is what you want.#set "?"}
If you'd like to have your prompt start in a newline, like I have in the
screenshot above, you just need to set -newline in the powerline-go
invocation in your .bashrc/.zshrc.
6) Gnome System Monitor Extension
Tips number 6 and 7 are for Gnome users.
Gnome is now shipping a system monitor extension which lets you get a glance of
the current load of your machine from the top bar.
I've found this quite useful for machines where I'm required to install
third-party monitoring software that tends to randomly consume more resources
than it should. If I feel like my machine is struggling, I can quickly glance
at its load to verify if it's getting overloaded by some process.
The extension is not as complete as
system-monitor-next,
not showing temperatures or histograms, but at least it's officially part of
Gnome, easy to install and supported by them.
And then enable the extension from the "Extension Manager" application.
7) Gnome setting for battery charging profile
After having to learn more about batteries in order to get into FPV drones,
I've come to have a bigger appreciation for solutions that minimize the
inevitable loss of capacity that accrues over time.
There's now a "Battery Charging" setting (under the "Power") section which lets
you choose between two different profiles: "Maximize Charge" and "Preserve
Battery Health".
On supported laptops, this setting is an easy way to set thresholds for when
charging should start and stop, just like you could do it with the tlp package,
but now from the Gnome settings.
To increase the longevity of my laptop battery, I always keep it at "Preserve
Battery Health" unless I'm traveling.
What I would like to see next is support for choosing different "Power Modes"
based on whether the laptop is plugged-in, and based on the battery
charge percentage.
There's a GNOME
issue
tracking this feature, but there's some pushback on whether this is the right
thing to expose to users.
In the meantime, there are some workarounds mentioned in that issue which
people who really want this feature can follow.
If you would like to learn more about batteries; Battery
University is a great starting point, besides
getting into FPV drones and being forced to handle batteries without a Battery
Management System (BMS).
And if by any chance this sparks your interest in FPV drones, Joshua Bardwell's
YouTube channel is a great resource:
@JoshuaBardwell.
8) Lazygit
Emacs users are already familiar with the legendary magit; a terminal-based
UI for git.
Lazygit is an alternative for non-emacs users, you can integrate it with neovim
or just use it directly.
I'm still playing with lazygit and haven't integrated it into my workflows,
but so far it has been a pleasant experience.
And then call lazygit from within a git repository.
9) neovim
neovim has been shipped in Debian since 2016, but upstream has been doing a lot of
work to improve the experience out-of-the-box in the last couple of years.
If you're a neovim poweruser, you're likely not installing it from the official
repositories, but for those that are, Debian 13 comes with version 0.10.4,
which brings the following improvements compared to the version in Debian 12:
Treesitter support for C, Lua, Markdown, with the possibility of adding any
other languages as needed;
Better spellchecking due to treesitter integration (spellsitter);
Mouse support enabled by default;
Commenting support out-of-the-box;
Check :h commenting for details, but the
tl;dr is that you can use gcc to comment the current line and gc to comment
the current selection.
OSC52 support.
Especially handy for those using neovim over an ssh
connection, this protocol lets you copy something from within the neovim
process into the clipboard of the machine you're using to connect through ssh.
In other words, you can copy from neovim running in a host over ssh and paste
it in the "outside" machine.
10) [Bonus] Running old Debian releases
The bonus tip is not specific to the Debian 13 release, but something I've
recently learned in the #debian-devel IRC channel.
Did you know there are usable container images for all past Debian releases?
I'm not talking "past" as in "some of the older releases", I'm talking past as
in "literally every Debian release, including the very first one".
Tianon Gravi "tianon" is the Debian Developer responsible for making this
happen, kudos to him!
There's a small gotcha that the releases Buzz (1.1) and Rex (1.2) require a
32-bit host, otherwise you will get the error Out of virtual memory!, but
starting with Bo (1.3) all should work in amd64/arm64.
Try it out:
sudo apt install podmanpodman run -it docker.io/debian/eol:bo
Don't be surprised when noticing that apt/apt-get is not available inside the
container, that's because apt first appeared in Debian Slink (2.1).
A bit more than a year ago, I had been thinking about making myself a
cartridge pleated skirt. For a number of reasons, one of which is the
historybounding potential, I’ve been thinking pre-crinoline, so
somewhere around the 1840s, and that’s a completely new era for me,
which means: new underwear.
Also, the 1840s are pre-sewing machine, and I was already in a position
where I had more chances to handsew than to machine sew, so I decided to
embrace the slowness and sew 100% by hand, not even using the machine
for straight seams.
If I remember correctly, I started with the corded petticoat, looking
around the internet for instructions, and then designing my own based on
the practicality of using modern wide fabric from my stash (and
specifically some DITTE from costumers’ favourite source of dirty cheap
cotton IKEA).
Around the same time I had also acquired a sashiko kit, and I used the
Japanese technique for sewing running stitches pushing the needle with a
thimble that covers the base of the middle finger, and I can confirm
that for this kind of things it’s great!
I’ve since worn the petticoat a few times for casual / historyBounding /
folkwearBounding reasons, during the summer, and I can confirm it’s
comfortable to use; I guess that during the winter it could be nice to
add a flannel layer below it.
Then I proceeded with the base layers: I had been browsing through
The workwoman's guide and that provided plenty of examples, and I
selected the basic ankle-length drawers from page 53 and the alternative
shift on page 47.
As for fabric, I had (and still have) a significant lack of underwear
linen in my stash, but I had plenty of cotton voile that I had not used
in a while: not very historically accurate for plain underwear, but
quite suitable for a wearable mockup.
Working with a 1830s source had an interesting aspect: other of the
usual, mildly annoying, imperial units, it also used a lot a few
obsolete units, especially nails, that my qalc, my usual calculator and
converter, doesn’t support.
Not a big deal, because GNU units came to the rescue, and that one
knows a lot of obscure and niche units, and it’s quite easy to add those
that are missing1
Working on this project also made me freshly aware of something I had
already noticed: converting instructions for machine sewing garments
into instructions for hand sewing them is usually straightforward, but
the reverse is not always true.
Starting from machine stitching, you can usually convert straight
stitches into backstitches (or running backstitches), zigzag and
overlocking into overcasting and get good results. In some cases you may
want to use specialist hand stitches that don’t really have a machine
equivalent, such as buttonhole stitches instead of simply overcasting
the buttonhole, but that’s it.
Starting from hand stitching, instead, there are a number of techniques
that could be converted to machine stitching, but involve a lot of
visible topstitching that wasn’t there in the original instructions, or
at times are almost impossible to do by machine, if they involve
whipstitching together finished panels on seams that are subject to
strong tension.
Anyway, halfway through working with the petticoat I cut both the
petticoat and the drawers at the same time, for efficiency in fabric
use, and then started sewing the drawers.
The book only provided measurements for one size (moderate), and my
fabric was a bit too narrow to make them that size (not that I have any
idea what hip circumference a person of moderate size was supposed to
have), so the result is just wide enough to be comfortably worn, but I
think that when I’ll make another pair I’ll try to make them a bit
wider. On the other hand they are a bit too long, but I think that I’ll
fix it by adding a tuck or two. Not a big deal, anyway.
The shift gave me a bit more issues: I used the recommended gusset size,
and ended up with a shift that was way too wide at the top, so I had to
take a box pleat in the center front and back, which changed the look
and wear of the garment. I have adjusted the instructions to make
gussets wider, and in the future I’ll make another shift following
those.
Even with the pleat, the narrow shoulder straps are set quite far to the
sides, and they tend to droop, and I suspect that this is to be expected
from the way this garment is made. The fact that there are buttonholes
on the shoulder straps to attach to the corset straps and prevent the
issue is probably a hint that this behaviour was to be expected.
I’ve also updated the instructions so that they shoulder straps are a
bit wider, to look more like the ones in the drawing from the book.
Making a corset suitable for the time period is something that I will
probably do, but not in the immediate future, but even just wearing the
shift under a later midbust corset with no shoulder strap helps.
I’m also not sure what the point of the bosom gores is, as they don’t
really give more room to the bust where it’s needed, but to the high
bust where it’s counterproductive. I also couldn’t find images of
original examples made from this pattern to see if they were actually
used, so in my next make I may just skip them.
On the other hand, I’m really happy with how cute the short sleeves
look, and if2 I’ll ever make the other cut of shift from the same
book, with the front flaps, I’ll definitely use these pleated sleeves
rather than the straight ones that were also used at the time.
As usual, all of the patterns have been published on my website under a
Free license:
I’ve just started using zram for swap on VMs. The use of compression for swap in Linux apparently isn’t new, it’s been in the Linux kernel since version 3.2 (since 2012). But until recent years I hadn’t used it. When I started using Mobian (the Debian distribution for phones) zram was in the default setup, it basically works and I never needed to bother with it which is exactly what you want from such a technology. After seeing it’s benefits in Mobian I started using it on my laptops where it worked well.
Benefits of ZRAM
ZRAM means that instead of paging data to storage it is compressed to another part of RAM. That means no access to storage which is a significant benefit if storage is slow (typical for phones) or if storage wearing out is a problem.
For servers you typically have SSDs that are fast and last for significant write volumes, for example the 120G SSDs referenced in my blog post about swap (not) breaking SSD [1] are running well in my parents’ PC because they outlasted all the other hardware connected to them and 120G isn’t usable for anything more demanding than my parents use nowadays. Those are Intel 120G 2.5″ DC grade SATA SSDs. For most servers ZRAM isn’t a good choice as you can just keep doing IO on the SSDs for years.
A server that runs multiple VMs is a special case because you want to isolate the VMs from each other. Support for quotas for storage IO in Linux isn’t easy to configure while limiting the number of CPU cores is very easy. If a system or VM using ZRAM for swap starts paging excessively the bottleneck will be CPU, this probably isn’t going to be great on a phone with a slow CPU but on a server class CPU it will be less of a limit. Whether compression is slower or faster than SSD is a complex issue but it will definitely be just a limit for that VM. When I setup a VM server I want to have some confidence that a DoS attack or configuration error on one VM isn’t going to destroy the performance of other VMs. If the VM server has 4 cores (the smallest VM server I run) and no VM has more than 2 cores then I know that the system can still run adequately if half the CPU performance is being wasted.
Some servers I run have storage limits that make saving the disk space for swap useful. For servers I run in Hetzner (currently only one server but I have run up to 6 at various times in the past) the storage is often limited, Hetzner seems to typically have storage that is 8* the size of RAM so if you have many VMs configured with the swap that they might need in the expectation that usually at most one of them will be actually swapping then it can make a real difference to usable storage. 5% of storage used for swap files isn’t uncommon or unreasonable.
Big Servers
I am still considering the implications of zram on larger systems. If I have a ML server with 512G of RAM would it make sense to use it? It seems plausible that a system might need 550G of RAM and zram could make the difference between jobs being killed with OOM and the jobs just completing. The CPU overhead of compression shouldn’t be an issue as when you have dozens of cores in the system having one or two used for compression is no big deal. If a system is doing strictly ML work there will be a lot of data that can’t be compressed, so the question is how much of the memory is raw input data and the weights used for calculations and how much is arrays with zeros and other things that are easy to compress.
With a big server nothing less than 32G of swap will make much difference to the way things work and if you have 32G of data being actively paged then the fastest NVMe devices probably won’t be enough to give usable performance. As zram uses one “stream” per CPU code if you have 44 cores that means 44 compression streams which should handle greater throughput. I’ll write another blog post if I get a chance to test this.
Some time ago, I wanted to encrypt a bunch of data in an application I was writing in Rust, mostly to be stored in a database, but also session cookies and sensitive configuration variables.
Since Rust is widely known as a secure-yet-high-performance programming language, I was expecting that there would be a widely-used crate that gave me a secure, high-level interface to strong, safe cryptography.
Imagine my surprise when I discovered that just… didn’t seem to exist.
Don’t get me wrong: Rust is replete with fast, secure, battle-tested cryptographic primitives.
The RustCrypto group provides all manner of robust, widely-used crates for all manner of cryptography-related purposes.
They’re the essential building blocks for practical cryptosystems, but using them directly in an application is somewhat akin to building a car from individual atoms of iron and carbon.
So I wrote my own high-level data encryption library, called it StrongBox, and have been happily encrypting and decrypting data ever since.
Cryptography So Simple Even I Can’t Get It Wrong
The core of StrongBox is the StrongBox trait, which has only two methods: encrypt and decrypt, each of which takes just two arguments.
The first argument is the plaintext (for encrypt) or the ciphertext (for decrypt) to work on.
The second argument is the encryption context, for use as Authenticated Additional Data, an important part of many uses of encryption.
There’s essentially no configuration or parameters to get wrong.
You can’t choose the encryption algorithm, or block cipher mode, and you don’t have to worry about generating a secure nonce.
You create a StrongBox with a key, and then you call encrypt and decrypt.
That’s it.
Practical Cryptographic Affordances
Ok, ok… that’s not quite it.
Because StrongBox is even easier to use than what I’ve described, thanks to the companion crate, StructBox.
When I started using StrongBox “in the wild”, it quickly became clear that what I almost always wanted to encrypt in my application wasn’t some ethereal “plaintext”.
I wanted to encrypt things, specifically structs (and enums).
So, through the magic of Rust derive macros, I built StructBox, which provides encrypt and decrypt operations on any Serde-able type.
Given that using Serde encoders can be a bit fiddly to use, it’s virtually easier to get an encrypted, serialized struct than it is to get a plaintext serialized struct.
Key Problems in Cryptography
The thing about cryptography is that it largely turns all data security problems into key management problems.
All the fancy cryptographic wonkery is for naught if you don’t manage the encryption keys well.
So, most of the fancy business in StrongBox isn’t the encryption and decryption, but instead solving problems around key management.
Different Keys for Different Purposes
Using the same key for all of your cryptographic needs is generally considered a really bad idea.
It opens up all manner of risks, that are easily avoided if you use different keys for different things.
However, having to maintain a big pile of different keys is a nightmare, so nobody’s going to do that.
Enter: key derivation.
Create one safe, secure “root” key, and then use a key derivation function to spawn as many other keys as you need.
Different keys for each database column, another one to encrypt cookies, and so on.
StrongBox supports this through the StemStrongBox type.
You’ll typically start off by creating a StemStrongBox with the “root” key, and then derive whatever other StrongBoxes you need, for encrypting and decrypting different kinds of data.
You Spin Me Round…
Sometimes, keys need to be rotated.
Whether that’s because you actually know (or even have reason to suspect) someone has gotten the key, or just because you’re being appropriately paranoid, sometimes key rotation has to happen.
As someone who has had to rotate keys in situations where such an eventuality was not planned for, I can say with some degree of authority: it absolutely sucks to have to do an emergency key rotation in a system that isn’t built to make that easy.
That’s why StrongBox natively supports key rotation.
Every StrongBox takes one encryption key, and an arbitrary number of decryption keys, and will automatically use the correct key to decrypt ciphertexts.
Will You Still Decrypt Me, Tomorrow?
In addition to “manual” key rotation, StrongBox also supports time-based key rotation with the RotatingStrongBox type.
This comes in handy when you’re encrypting a lot of “ephemeral” data, like cookies (or server-side session data).
It provides a way to automatically “expire” old data, and prevents attacks that become practical when large amounts of data are encrypted using a single key.
Invasion of the Invisible Salamanders!
I mostly mention this just because I love the name, but there is a kind of attack possible in common AEAD modes called the invisible salamanders attack.
StrongBox implements mitigations against this, by committing to the key being used so that an attacker can’t forge a ciphertext that decrypts validly to different plaintexts when using different keys.
This is why I love cryptography: everything sounds like absolute goddamn magic.
Call Me Crazy, Support Me Maybe?
If you’re coding in Rust (which you probably should be), encrypting your stored data (which you definitely should be), and StrongBox makes your life easier (which it really will), you can show your appreciation for my work by contributing to my open source code-fund.
Simply by shouting me a refreshing beverage, you’ll be helping me out, and helping to grow the software commons.
Alternately, if you’re looking for someone to Speak Rust to Computers on a professional basis, I’m available for contracts or full-time remote positions.
“The Comedy of Computation” is not an easy book to review. It is a much
enjoyable book that analyzes several examples of how “being computational”
has been approached across literary genres in the last century — how
authors of stories, novels, theatrical plays and movies, focusing on
comedic genres, have understood the role of the computer in defining human
relations, reactions and even self-image.
Mangrum structures his work in six thematic chapters, where he presents
different angles on human society: How have racial stereotypes advanced in
human imagination and perception about a future where we interact with
mechanical or computational partners (from mechanical tools performing jobs
that were identified with racial profiles to intelligent robots that
threaten to control society); the genericity of computers –and people– can
be seen as generic, interchangeable characters, often fueled by the
tendency people exhibit to confer anthropomorphic qualities to inanimate
objects; people’s desire to be seen as “truly authentic”, regardless of
what it ultimately means; romantic involvement and romance-led stories
(with the computer seen as a facilitator for human-to-human romances,
distractor away from them, or being itself a part of the couple); and the
absurdity in antropomorphization, in comparing fundamentally different
aspects such as intelligence and speed at solving mathematical operations,
as well as the absurdity presented blatantly as such by several
techno-utopian visions.
But presenting this as a linear set of concepts that are presented does not
do justice to the book. Throughout the sections of each chapter, a
different work serves as the axis — Novels and stories, Hollywood movies,
Broadway plays, some covers for the Time magazine, a couple of
presenting the would-be future, even a romantic comedy entirely written by
“bots”. And for each of them, Benjamin Mangrum presents a very thorough
analysis, drawing relations and comparing with contemporary works, but also
with Shakespeare, classical Greek myths, and a very long etcætera. This
book is hard to review because of the depth of work the author did: Reading
it repeatedly made me look for other works, or at least longer references
for them.
Still, despite being a work with such erudition, Mangrum’s text is easy and
pleasant to read, without feeling heavy or written in an overly academic
style. I very much enjoyed reading this book. It is certainly not a
technical book about computers and society in any way; it is an exploration
of human creativity and our understanding of the aspects the author has
found as central to understanding the impact of computing on humankind.
However, there is one point I must mention before closing: I believe the
editorial decision to present the work as a running text, with all the
material conceptualized as footnotes presented as a separate, over 50 page
long final chapter, detracts from the final result. Personally, I enjoy
reading the footnotes because they reveal the author’s thought processes,
even if they stray from the central line of thought. Even more, given my
review copy was a PDF, I could not even keep said chapter open with one
finger, bouncing back and forth. For all purposes, I missed out on the
notes; now that I finished reading and stumbled upon that chapter, I know I
missed an important part of the enjoyment.
Today marks both a milestone and a turning point in my journey with open source software. I’m proud to announce the release of KDE Gear 25.08.0 as my final snap package release. You can find all the details about this exciting update at the official KDE announcement.
After much reflection and with a heavy heart, I’ve made the difficult decision to retire from most of my open source software work, including snap packaging. This wasn’t a choice I made lightly – it comes after months of rejections and silence in an industry I’ve loved and called home for over 20 years.
Passing the Torch
While I’m stepping back, I’m thrilled to share that the future of KDE snaps is in excellent hands. Carlos from the Neon team has been working tirelessly to set up snaps on the new infrastructure that KDE has made available. This means building snaps in KDE CI is now possible – a significant leap forward for the ecosystem. I’ll be helping Carlos get the pipelines properly configured to ensure a smooth transition.
Staying Connected (But Differently)
Though I’m stepping away from most development work, I won’t be disappearing entirely from the communities that have meant so much to me:
Kubuntu: I’ll remain available as a backup, though Rik is doing an absolutely fabulous job getting the latest and greatest KDE packages uploaded. The distribution is in capable hands.
Ubuntu Community Council: I’m continuing my involvement here because I’ve found myself genuinely enjoying the community side of things. There’s something deeply fulfilling about focusing on the human connections that make these projects possible.
Debian: I’ll likely be submitting for emeritus status, as I haven’t had the time to contribute meaningfully and want to be honest about my current capacity.
The Reality Behind the Decision
This transition isn’t just about career fatigue – it’s about financial reality. I’ve spent too many years working for free while struggling to pay my bills. The recent changes in the industry, particularly with AI transforming the web development landscape, have made things even more challenging. Getting traffic to websites now requires extensive social media work and marketing – all expected to be done without compensation.
My stint at webwork was good while it lasted, but the changing landscape has made it unsustainable. I’ve reached a point where I can’t continue doing free work when my family and I are struggling financially. It shouldn’t take breaking a limb to receive the donations needed to survive.
A Career That Meant Everything
These 20+ years in open source have been the defining chapter of my professional life. I’ve watched communities grow, technologies evolve, and witnessed firsthand the incredible things that happen when passionate people work together. The relationships I’ve built, the problems we’ve solved together, and the software we’ve created have been deeply meaningful.
But I also have to be honest about where I stand today: I cannot compete in the current job market. The industry has changed, and despite my experience and passion, the opportunities just aren’t there for someone in my situation.
Looking Forward
Making a career change after two decades is terrifying, but it’s also necessary. I need to find a path that can provide financial stability for my family while still allowing me to contribute meaningfully to the world.
If you’ve benefited from my work over the years and are in a position to help during this transition, I would be forever grateful for any support. Every contribution, no matter the size, helps ease this difficult period: https://gofund.me/a9c55d8f
Thank You
To everyone who has collaborated with me, tested my packages, filed bug reports, offered encouragement, or simply used the software I’ve helped maintain – thank you. You’ve made these 20+ years worthwhile, and you’ve been part of something bigger than any individual contribution.
The open source world will continue to thrive because it’s built on the collective passion of thousands of people like Carlos, Rik, and countless others who are carrying the torch forward. While my active development days are ending, the impact of this community will continue long into the future.
I use sway as window manager on my main machine. As I prefer dark mode, I looked for a way to enable dark mode everywhere.
For GTK-based this is fairly straightforward: Just install whatever theme you prefer, and apply it.
However, QT-based applications on a non-QT based desktop will look …
As per the previous Polkit blog post the policykit framwork has lost the ability to understand its own .pkla files and policies need to be expressed in Javascript with .rules files now.
To re-enable allowing remote users (think ssh) to reboot, hibernate, suspend or power off the local system, create a 10-shutdown-reboot.rules file in /etc/polkit-1/rules.d/:
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