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Raphaël Hertzog: Freexian’s report about Debian Long Term Support, April 2017

16 May, 2017 - 22:52

Like each month, here comes a report about the work of paid contributors to Debian LTS.

Individual reports

In April, about 190 work hours have been dispatched among 13 paid contributors. Their reports are available:

  • Antoine Beaupré did 19.5 hours (out of 16h allocated + 5.5 remaining hours, thus keeping 2 extra hours for May).
  • Ben Hutchings did 12 hours (out of 15h allocated, thus keeping 3 extra hours for May).
  • Brian May did 10 hours.
  • Chris Lamb did 18 hours.
  • Emilio Pozuelo Monfort did 17.5 hours (out of 16 hours allocated + 3.5 hours remaining, thus keeping 2 hours for May).
  • Guido Günther did 12 hours (out of 8 hours allocated + 4 hours remaining).
  • Hugo Lefeuvre did 15.5 hours (out of 6 hours allocated + 9.5 hours remaining).
  • Jonas Meurer did nothing (out of 4 hours allocated + 3.5 hours remaining, thus keeping 7.5 hours for May).
  • Markus Koschany did 23.75 hours.
  • Ola Lundqvist did 14 hours (out of 20h allocated, thus keeping 6 extra hours for May).
  • Raphaël Hertzog did 11.25 hours (out of 10 hours allocated + 1.25 hours remaining).
  • Roberto C. Sanchez did 16.5 hours (out of 20 hours allocated + 1 hour remaining, thus keeping 4.5 extra hours for May).
  • Thorsten Alteholz did 23.75 hours.
Evolution of the situation

The number of sponsored hours decreased slightly and we’re now again a little behind our objective.

The security tracker currently lists 54 packages with a known CVE and the dla-needed.txt file 37. The number of open issues is comparable to last month.

Thanks to our sponsors

New sponsors are in bold.

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Francois Marier: Recovering from an unbootable Ubuntu encrypted LVM root partition

16 May, 2017 - 11:10

A laptop that was installed using the default Ubuntu 16.10 (xenial) full-disk encryption option stopped booting after receiving a kernel update somewhere on the way to Ubuntu 17.04 (zesty).

After showing the boot screen for about 30 seconds, a busybox shell pops up:

BusyBox v.1.21.1 (Ubuntu 1:1.21.1-1ubuntu1) built-in shell (ash)
Enter 'help' for list of built-in commands.

(initramfs)

Typing exit will display more information about the failure before bringing us back to the same busybox shell:

Gave up waiting for root device. Common problems:
  - Boot args (cat /proc/cmdline)
    - Check rootdelay= (did the system wait long enough?)
    - Check root= (did the system wait for the right device?)
  - Missing modules (cat /proc/modules; ls /dev)
ALERT! /dev/mapper/ubuntu--vg-root does not exist. Dropping to a shell! 

BusyBox v.1.21.1 (Ubuntu 1:1.21.1-1ubuntu1) built-in shell (ash)   
Enter 'help' for list of built-in commands.  

(initramfs)

which now complains that the /dev/mapper/ubuntu--vg-root root partition (which uses LUKS and LVM) cannot be found.

There is some comprehensive advice out there but it didn't quite work for me. This is how I ended up resolving the problem.

Boot using a USB installation disk

First, create bootable USB disk using the latest Ubuntu installer:

  1. Download an desktop image.
  2. Copy the ISO directly on the USB stick (overwriting it in the process):

     dd if=ubuntu.iso of=/dev/sdc1
    

and boot the system using that USB stick (hold the option key during boot on Apple hardware).

Mount the encrypted partition

Assuming a drive which is partitioned this way:

  • /dev/sda1: EFI partition
  • /dev/sda2: unencrypted boot partition
  • /dev/sda3: encrypted LVM partition

Open a terminal and mount the required partitions:

cryptsetup luksOpen /dev/sda3 sda3_crypt
vgchange -ay
mount /dev/mapper/ubuntu--vg-root /mnt
mount /dev/sda2 /mnt/boot
mount -t proc proc /mnt/proc
mount -o bind /dev /mnt/dev

Note:

  • When running cryptsetup luksOpen, you must use the same name as the one that is in /etc/crypttab on the root parition (sda3_crypt in this example).

  • All of these partitions must be present (including /proc and /dev) for the initramfs scripts to do all of their work. If you see errors or warnings, you must resolve them.

Regenerate the initramfs on the boot partition

Then "enter" the root partition using:

chroot /mnt

and make sure that the lvm2 package is installed:

apt install lvm2

before regenerating the initramfs for all of the installed kernels:

update-initramfs -c -k all

Gunnar Wolf: Starting a project on private and anonymous network usage

15 May, 2017 - 23:43

I am starting a work with the students of LIDSOL (Laboratorio de Investigación y Desarrollo de Software Libre, Free Software Research and Development Laboratory) of the Engineering Faculty of UNAM:

We want to dig into the technical and social implications of mechanisms that provide for anonymous, private usage of the network. We will have our first formal work session this Wednesday, for which we have invited several interesting people to join the discussion and help provide a path for our oncoming work. Our invited and confirmed guests are, in alphabetical order:

  • Salvador Alcántar (Wikimedia México)
  • Sandino Araico (1101)
  • Gina Gallegos (ESIME Culhuacán)
  • Juliana Guerra (Derechos Digitales)
  • Jacobo Nájera (Enjambre Digital)
  • Raúl Ornelas (Instituto de Investigaciones Económicas)

  • As well as LIDSOL's own teachers and students.
    This first session is mostly exploratory, we should keep notes and decide which directions to pursue to begin with. Do note that by "research" we are starting from the undergraduate student level — Not that we want to start by changing the world. But we do want to empower the students who have joined our laboratory to change themselves and change the world. Of course, helping such goals via the knowledge and involvement of projects (not just the tools!) such as Tor.

Michal Čihař: New projects on Hosted Weblate

15 May, 2017 - 23:00

Hosted Weblate provides also free hosting for free software projects. The hosting requests queue was over one month long, so it's time to process it and include new project.

This time, the newly hosted projects include:

We now also host few new Minetest mods:

If you want to support this effort, please donate to Weblate, especially recurring donations are welcome to make this service alive. You can do them on Liberapay or Bountysource.

Filed under: Debian English SUSE Weblate | 0 comments

intrigeri: GNOME and Debian usability testing, May 2017

15 May, 2017 - 18:04

During the Contribute your skills to Debian event that took place in Paris last week-end, we conducted a usability testing session. Six people were tasked with testing a few aspects of the GNOME 3.22 desktop environment and of the Debian 9 (Stretch) operating system. A number of other people observed them and took notes. Then, two observers and three testers analyzed the results, that we are hereby presenting: we created a heat map visualization, summed up the challenges met during the tests, and wrote this blog post together. We will point the relevant upstream projects to our results.

A couple of other people also did some usability testing but went in much more depth: their feedback is much more detailed and comes with a number of improvement ideas. I will process and publish their results as soon as possible.

Missions

Testers were provided a laptop running GNOME on a a Debian 9 (Stretch) Live system. A quick introduction (mostly copied from the one we found in some GNOME usability testing reports) was read. Then they were asked to complete the following tasks.

A. Nautilus Mission A.1 — Download and rename file in Nautilus
  1. Download a file from the web, a PDF document for example.
  2. Open the folder in which the file has been downloaded.
  3. Rename the dowloaded file to SUCCESS.pdf.
  4. Toggle the browser window to full screen.
  5. Open the file SUCCESS.pdf.
  6. Go back to the File manager.
  7. Close the file SUCCESS.pdf.
Mission A.2 — Manipulate folders in Nautilus
  1. Create a new folder named cats in your user directory.
  2. Create a new folder named to do in your user directory.
  3. Move the cats folder to the to do folder.
  4. Delete the cats folder.
Mission A.3 — Create a bookmark in Nautilus
  1. Create a folder named unicorns in your personal directory.
  2. This folder is important. Add a bookmark for unicorns in order to find it again in a few weeks.
Mission A.4 — Nautilus display settings

Folders and files are usually listed as icons, but they can also be displayed differently.

  1. Configure the File manager to make it show items as a list, with one file per line.
  2. You forgot your glasses and the font size is too small for you to see the text: increase the size of the text.
B. Package management Introduction

On Debian, each application is available as a "package" which contains every file needed for the software to work.

Unlike in other operating systems, it is rarely necessary and almost never a good idea, to download and install software from the authors website. We can rather install it from an online library managed by Debian (like an appstore). This alternative offers several advantages, such as being able to update all the software installed in one single action.

Specific tools are available to install and update Debian packages.

Mission B.1 — Install and remove packages
  1. Install the vlc package.
  2. Start VLC.
  3. Remove the vlc package.
Mission B.2 — Search and install a package
  1. Find a piece of software which can download files with BitTorrent in a graphical interface.
  2. Install the corresponding package.
  3. Launch that BitTorrent software.
Mission B.3 — Upgrade the system

Make sure the whole system (meaning all installed packages) is up to date.

C. Settings Mission C.1 — Change the desktop background
  1. Download an image you like from the web.
  2. Set the downloaded image as the desktop wallpaper.
Mission C.2 — Tweak temporary files management

Configure the system so that temporary files older than three days are deleted automatically.

Mission C.3 — Change the default video player
  1. Install VLC (ask for help if you could not do it during the previous mission).
  2. Make VLC the default video player.
  3. Download a video file from the web.
  4. Open the downloaded video, then check if it opens with VLC.
Mission C.4 — Add and remove world clocks

When you click the time and date in the top bar, a menu pops-up. There, you can display clocks in several time-zones.

  1. Add a clock with Rio de Janeiro timezone, then another showing the current time in Boston.
  2. Check that the time and date menu now displays these two additional clocks.
  3. Remove the Boston clock.
Results and analysis Heat map

We used Jim Hall's heat map technique to summarize our usability test results. As Renata puts it, it is "a great way to see how the users performed on each task. The heat map clarifies how easy or difficult it was for the participant to accomplish a certain task.

  1. Scenario tasks (from the usability test) are arranged in rows.
  2. Test participants (for each tester) are arranged in columns.
  3. The colored blocks represent each tester’s difficulty with each scenario task.

Green blocks represent the ability of the participant to accomplish the tasks with little or no difficulty.

Yellow blocks indicate the tasks that the tester had significant difficulties accomplishing.

Red blocks indicate that testers experienced extreme difficulty or where testers completed the tasks incorrectly.

Black blocks indicate tasks the tester was unable to complete."

Most tasks were accomplished with little or no difficulty so we will now focus on the problematic parts.

What were the challenges?

The heat map shows several "hot" rows, that we will now be looking at in more details.

Mission A.3 — Create a bookmark in Nautilus

Most testers right-clicked the folder first, and eventually found they could simply drag'n'drop to the bookmarks location in the sidebar.

One tester thought that he could select a folder, click the hamburger icon, and from there use the "Bookmark this folder" menu item. However, this menu action only works on the folder one has entered, not on the selected one.

Mission B.1 — Install and remove a package

Here we faced a number of issues caused by the fact that Debian Live images don't include package indices (with good reason), so no package manager can list available software.

Everyone managed to start a graphical package manager via the Overview (or via the CLI or Alt-F2 for a couple power users).

Some testers tried to use GNOME Software, which listed only already installed packages (Debian bug #862560) and provided no way we could find to refresh the package indices. That's arguably a bug in Debian Live, but still: GNOME Software might display some useful information when it detects this unusual situation.

We won't list here all the obstacles that were met in Synaptic: it's no news its usability is rather sub-optimal and better alternatives (such as GNOME Software) are in the works.

Mission C.2 — Tweak temporary files management

The mission was poorly phrased: some observers had to clarify that it was specifically about GNOME, and not generic Linux system administration: some power-users were already searching the web for command-line tools to address the task at hand.

Even with this clarification, no tester would have succeeded without being told they were allowed to use the web with a search query including the word "GNOME", or use the GNOME help or the Overview. Yet eventually all testers succeeded.

It's interesting to note that regular GNOME users had the same problem as others: they did not try searching "temporary" in the Overview and did not look-up the GNOME Help until they were suggested to do so.

Mission C.3 — Change the default video player

One tester configured one single video file format to be opened by default with VLC, via right-click in Nautilus → Open with → etc. He believed this would be enough to make VLC the default video player, missing the subtle difference between "default video player" and "default player for one single video format".

One tester tried to complete this task inside VLC itself and then needed some help to succeed. It might be that the way web browsers ask "Do you want ThisBrowser to become the default web browser?" gave a hint an application GUI is the right place to do it.

Two testers searched "default" in the Overview (perhaps the previous mission dealing with temporary files was enough to put them in this direction). At least one tester was confused since the only search result (Details – View information about your system), which is the correct one to get there, includes the word View, which suggests that one cannot modify settings there, but only view them.

One long-term GNOME user looked in Tweak Tool first, and then used the Overview.

Here again, GNOME users experienced essentially the same issues as others.

Mission C.4 — Add and remove world clocks

One tester tried to look for the clock on the top right corner of the screen, then realized it was in the middle. Other than this, all testers easily found a way to add world clocks.

However, removing a world clock was rather difficult; although most testers managed to do it, it took them a number of attempts to succeed:

  1. Several testers left-clicked or right-clicked the clock they wanted to remove, expecting this would provide them with a way to remove it (which is not the case).
  2. After a while, all testers noticed the Select button (that has no text label nor tooltip info), which allowed them to select the clock they wanted to remove; then, most testers clicked the 1 selected button, hoping it would provide a contextual menu or some other way to act on the selected clocks (it doesn't).
  3. Eventually, everyone managed to locate the Delete button on the bottom right corner of the window; some testers mentioned that it is less visible and flashy than the blue bar that appears on the top of the screen once they had entered "Selection" mode.
General notes and observations
  • None of the participants sollicited the GNOME Help, which is unfortunate knowing its:
    • great quality;
    • translations in several languages;
    • availability and adaptability to regional specifications;
    • adequacy to the currently running version of GNOME.

    Some users found the relevant help page online via web searches; others initially ignored it among search results, then looked for it later after being told that the mission was more about GNOME.

  • Whether testers were already GNOME users or not seldom impacted their chances of success.
  • Unfortunately, we haven't compiled enough information about the testers to provide useful data about who they are and what their background is. Still, we had an interesting mix in terms of genders, age (between 17 and 52 years old), skin color and computer experience.

Steve Kemp: Some minor updates ..

15 May, 2017 - 04:00

The past few weeks have been randomly busy, nothing huge has happened, but several minor diversions.

Coding

I made a new release of my console-based mail-client, with integrated Lua scripting, this is available for download over at https://lumail.org/

I've also given a talk (!!) on using a literate/markdown configuration for GNU Emacs. In brief I created two files:

~/.emacs/init.md

This contains both my configuration of GNU Emacs as well as documentation for the same. Neat.

~/.emacs/init.el

This parse the previous file, specifically looking for "code blocks" which are then extracted and evaluated.

This system is easy to maintain, and I'm quite happy with it :)

Fuzzing

Somebody nice took the time to report a couple of bugs against my simple bytecode-intepretting virtual-machine project - all found via fuzzing.

I've done some fun fuzzing of my own in the past, so this was nice to see. I've now resolved those bugs, and updated the README.md file to include instructions on fuzzing it. (Which I started doing myself, after receiving the first of the reports )

Finally I have more personal news too: I had a pair of CT-scans carried out recently, and apparently here in sunny Finland (that's me being ironic, it was snowing in the first week of May) when you undergo a CT-scan you can pay to obtain your data on CD-ROM.

I'm 100% definitely going to get a copy of my brain-scan data. I'll be able to view a 3d-rendered model of my own brain on my desktop. (Once upon a time I worked for a company that produced software, sold to doctors/surgeons, for creating 3d-rendered volumes from individual slices. I confirmed with the radiologist that handled my tests that they do indeed use the standard DICOM format. Small world.)

Bits from Debian: New Debian Developers and Maintainers (March and April 2017)

14 May, 2017 - 19:30

The following contributors got their Debian Developer accounts in the last two months:

  • Guilhem Moulin (guilhem)
  • Lisa Baron (jeffity)
  • Punit Agrawal (punit)

The following contributors were added as Debian Maintainers in the last two months:

  • Sebastien Jodogne
  • Félix Lechner
  • Uli Scholler
  • Aurélien Couderc
  • Ondřej Kobližek
  • Patricio Paez

Congratulations!

Russ Allbery: Review: The Raven and the Reindeer

14 May, 2017 - 07:08

Review: The Raven and the Reindeer, by T. Kingfisher

Publisher: Red Wombat Tea Company Copyright: 2016 ASIN: B01BKTT73A Format: Kindle Pages: 191

Once upon a time, there was a boy born with frost in his eyes and frost in his heart.

There are a hundred stories about why this happens. Some of them are close to true. Most of them are merely there to absolve the rest of us of blame.

It happens. Sometimes it's no one's fault.

Kay is the boy with frost in his heart. Gerta grew up next door. They were inseparable as children, playing together on cold winter days. Gerta was in love with Kay for as long as she could remember. Kay, on the other hand, was, well, kind of a jerk.

There are not many stories about this sort of thing. There ought to be more. Perhaps if there were, the Gertas of the world would learn to recognize it.

Perhaps not. It is hard to see a story when you are standing in the middle of it.

Then, one night, Kay is kidnapped in the middle of the night by the Snow Queen while Gerta watches, helpless. She's convinced that she's dreaming, but when she wakes up, Kay is indeed gone, and eventually the villagers stop the search. But Gerta has defined herself around Kay her whole life, so she sets off, determined to find him, totally unprepared for the journey but filled with enough stubborn, practical persistence to overcome a surprising number of obstacles.

Depending on your past reading experience (and cultural consumption in general), there are two things that may be immediately obvious from this beginning. First, it's written by Ursula Vernon, under her T. Kingfisher pseudonym that she uses for more adult fiction. No one else has quite that same turn of phrase, or writes protagonists with quite the same sort of overwhelmed but stubborn determination. Second, it's a retelling of Hans Christian Andersen's "The Snow Queen."

I knew the first, obviously. I was completely oblivious to the second, having never read "The Snow Queen," or anything else by Andersen for that matter. I haven't even seen Frozen. I therefore can't comment in too much detail on the parallels and divergences between Kingfisher's telling and Andersen's (although you can read the original to compare if you want) other than some research on Wikipedia. As you might be able to tell from the quote above, though, Kingfisher is rather less impressed by the idea of childhood true love than Andersen was. This is not the sort of story in which the protagonist rescues the captive boy through the power of pure love. It's something quite a bit more complicated and interesting: a coming-of-age story for Gerta, in which her innocence is much less valuable than her fundamental decency, empathy, and courage, and in which her motives for her journey change as the journey proceeds. It helps that Kingfisher's world is populated by less idealized characters, many of whom are neither wholly bad nor wholly good, but who think of themselves as basically decent and try to do vaguely the right thing. Although sometimes they need some reminding.

The story does feature a talking raven. (Most certainly not a crow.) His name is the Sound of Mouse Bones Crunching Under the Hooves of God. He's quite possibly the best part.

Gerta does not rescue Kay through the power of pure love. But there is love here, of a sort that Gerta wasn't expecting at all, and of a sort that Andersen never had in mind when he wrote the original. There's also some beautifully-described shapeshifting, delightful old women, and otters. (Also, I find the boy who appears at the very end of the story utterly fascinating, with all his implied parallel story and the implicit recognition that the world does not revolve around Kay and Greta.) But I think my favorite part is how clearly different Greta is at the end of her journey than at the beginning, how subtly Kingfisher makes that happen through the course of the story, and how understated but just right her actions are at the very end.

This is really excellent stuff. The next time you're feeling in the mood for a retold and modernized fairy tale, I recommend it.

Rating: 8 out of 10

Vincent Fourmond: Run QSoas complely non-interactively

14 May, 2017 - 05:45
QSoas can run scripts, and, since version 2.0, it can be run completely without user interaction from the command-line (though an interface may be briefly displayed). This possibility relies on the following command-line options:

  • --run, which runs the command given on the command-line;
  • --exit-after-running, which closes automatically QSoas after all the commands specified by --run were run;
  • --stdout (since version 2.1), which redirects QSoas's terminal directly to the shell output.
If you create a script.cmds file containing the following commands:
generate-buffer -10 10 sin(x)
save sin.dat
and run the following command from your favorite command-line interpreter:
~ QSoas --stdout --run '@ script.cmds' --exit-after-running
This will create a sin.dat file containing a sinusoid. However, if you run it twice, a Overwrite file 'sin.dat' ? dialog box will pop up. You can prevent that by adding the /overwrite=true option to save. As a general rule, you should avoid all commands that may ask questions in the scripts; a /overwrite=true option is also available for save-buffers for instance.

I use this possibility massively because I don't like to store processed files, I prefer to store the original data files and run a script to generate the processed data when I want to plot or to further process them. It can also be used to generate fitted data from saved parameters files. I use this to run automatic tests on Linux, Windows and Mac for every single build, in order to quickly spot platform-specific regressions.

To help you make use of this possibility, here is a shell function (Linux/Mac users only, add to your $HOME/.bashrc file or equivalent, and restart a terminal) to run directly on QSoas command files:

qs-run () {
        QSoas --stdout --run "@ $1" --exit-after-running
}
To run the script.cmds script above, just run
~ qs-run script.cmds

About QSoasQSoas is a powerful open source data analysis program that focuses on flexibility and powerful fitting capacities. It is described in Fourmond, Anal. Chem., 2016, 88 (10), pp 5050–5052. Current version is 2.1

Ricardo Mones: Disabling "flat-volumes" in pulseaudio

13 May, 2017 - 22:12
Today I've just faced another of those happy ideas some people implements in software, which can be useful for some cases, but can also also be bad as default behaviour.

The problems caused were already posted to Debian mailing lists, fortunately, as well as its solution, which basically in a default Debian configuration means to:

$ sudo echo "flat-volumes = no" >> /etc/pulse/daemon.conf
$ pulseaudio -k && pulseaudio

And I think the default for Stretch should be set as above: raising volume to 100% just because of a system notification, while useful for some, it's not what common users expect.

Steve McIntyre: Fonts and presentations

13 May, 2017 - 05:08

When you're giving a presentation, the choice of font can matter a lot. Not just in terms of how pretty your slides look, but also in terms of whether the data you're presenting is actually properly legible. Unfortunately, far too many fonts are appallingly bad if you're trying to tell certain characters apart. Imagine if you're at the back of a room, trying to read information on a slide that's (typically) too small and (if you're unlucky) the presenter's speech is also unclear to you (noisy room, bad audio, different language). A good clear font is really important here.

To illustrate the problem, I've picked a few fonts available in Google Slides. I've written the characters "1lIoO0" (that's one, lower case L, upper case I, lower case o, upper case O, zero) in each of those fonts. Some of the sans-serif fonts in particular are comically bad for trying to distinguish between these characters.

It may not matter in all cases if your audience can read all the characters on your slides and tell them apart, put if you're trying to present scientific or numeric results it's critical. Please consider that before looking for a pretty font.

Daniel Pocock: Thank you to the OSCAL team

12 May, 2017 - 20:26

The welcome gift deserves its own blog post. If you want to know what is inside, I hope to see you at OSCAL'17.

Martín Ferrari: 6 days to SunCamp

12 May, 2017 - 17:21

Only six more days to go before SunCamp! If you are still considering it, hurry up, you might still find cheap tickets for the low season.

It will be a small event (about 20-25 people), with a more intimate atmosphere than DebConf. There will be people fixing RC bugs, preparing stuff for after the release, or just discussing with other Debian folks.

There will be at least one presentation from a local project, and surely some members of nearby communities will join us for the day like they did last year.

See you all in Lloret!

Comment

Daniel Pocock: Kamailio World and FSFE team visit, Tirana arrival

12 May, 2017 - 16:48

This week I've been thrilled to be in Berlin for Kamailio World 2017, one of the highlights of the SIP, VoIP and telephony enthusiast's calendar. It is an event that reaches far beyond Kamailio and is well attended by leaders of many of the well known free software projects in this space.

HOMER 6 is coming

Alexandr Dubovikov gave me a sneak peek of the new version of the HOMER SIP capture framework for gathering, storing and analyzing messages in a SIP network.

Visiting the FSFE team in Berlin

Having recently joined the FSFE's General Assembly as the fellowship representative, I've been keen to get to know more about the organization. My visit to the FSFE office involved a wide-ranging discussion with Erik Albers about the fellowship program and FSFE in general.

Steak and SDR night

After a hard day of SIP hacking and a long afternoon at Kamailio World's open bar, a developer needs a decent meal and something previously unseen to hack on. A group of us settled at Escados, Alexanderplatz where my SDR kit emerged from my bag and other Debian users found out how easy it is to apt install the packages, attach the dongle and explore the radio spectrum.

Next stop OSCAL'17, Tirana

Having left Berlin, I'm now in Tirana, Albania where I'll give an SDR workshop and Free-RTC talk at OSCAL'17. The weather forecast is between 26 - 28 degrees celsius, the food is great and the weekend's schedule is full of interesting talks and workshops. The organizing team have already made me feel very welcome here, meeting me at the airport and leaving a very generous basket of gifts in my hotel room. OSCAL has emerged as a significant annual event in the free software world and if it's too late for you to come this year, don't miss it in 2018.

Norbert Preining: Gaisi Takeuti, 1926-2017

12 May, 2017 - 07:59

Two days ago one of the most influential logician of the 20th century has passed away, Gaisi Takeuti (竹内 外史). I had the pleasure to meet this excellent man, teacher, writer, thinker several times while he was the president of the Kurt Gödel Society.

I don’t want to recall his achievements in mathematical logic, in particular proof theory, because I am not worth to write about such a genius. I want to recall a few personal stories from my own experience.

I came into contact with Prof. Takeuti via is famous book Proof Theory, which my then Professor, now colleague and friend Matthias Baaz used for teaching us students proof theory. Together with Shoenfield’s Mathematical Logic these two books became the foundation of my whole logic education. Now again in print, back then the “Proof Theory” was a rare precious. Few prints did remain in the library, and over the years one by one disappeared, until the last copy we had access to was my copy where I had scribbled pages and pages of notes and proofs. Matthias later on used these copies for his lectures, I should have written on the back-side!

I remember well my first meeting with Prof. Takeuti: I was on the Conference on Internationalization in 2003 in Tsukuba, long before I moved to Japan. Back then I was just finishing my PhD and without much experience. When I arrived in the hotel, without fail there was a message of Prof. Takeuti inviting me for dinner the following day. We had dinner in a specialty restaurant of his area, together with is lovely wife. I was soo nervous about Japanese manners and stuttered Japanese phrases – just to be stopped by Prof. Takeuti pouring himself a glass of sake and telling me: Relax, and forget the rules and fill your own glass when you want to. I am well aware that this liberal attitude didn’t extend to Japanese colleagues, where he, descendant from a Samurai family, was at times very, extremely strict.

The dinner was decided upon already, not easy since I was still strict vegetarian back than (now I would have enjoyed the dinner much more!), but for the last course we could decide. I remember with a smile how Prof. Takeuti suggested in Japanese various sweets, just to be interrupted by his wife with “No Gaisi, no!”. I asked what is going on and she explained that he wants to order a Japanese sweet for me – I agreed, and that was probably the worst dish I had in Japan. Slippy noodles swimming in a cold broth, to be picked with chopsticks and put into a semi-sweet soja-sauce. I finished it, but it wasn’t good. I should have thought twice when Prof. Takeuti’s wife ordered a normal fruit salad.

Scientifically he was simply a genius – and famous for not reading a lot but reinventing everything. One of my research areas, Gödel logics, was reinvented by him as “Intuitionistic Fuzzy Logic” (for an overview see my talk at the Collegium Logicum 2016: Gödel Logics – a short survey). But I want to recall one of my favorite articles of him: “A Conservative Extension of Peano Arithmetic”. This was published as part 2 of Volume 17 of Publications of the Mathematical Society of Japan, retypeset pdf is available here, JSTOR page. Therein he develops classical (real and complex) analysis over Peano’s arithmetic. He shows that any arithmetical theorem proved in analytic number theory is a theorem in Peano’s arithmetic. The proof uses Gentzen’s cut elimination theorem, the center piece of modern proof theory.

With Georg Kreisel having passed away in 2017, and now Gaisi Takeuti, we loose two of the greatest, if not the greatest minds in logic.

Arturo Borrero González: Debunk some Debian myths

11 May, 2017 - 23:21

Debian has many years of history, about 25 years already. With such a long travel over the continous field of developing our Universal Operating System, some miths, false accusations and bad reputation has arisen.

Today I had the oportunity to discuss this topic, I was invited to give a Debian talk in the “11º Concurso Universitario de Software Libre”, a spanish contest for students to develop and dig a bit into free-libre open source software (and hardware).

In this talk, I walked through some of the most common debian myts, and I would like to summarice here some of them, with a short explanation of why I think they should be debunked.

myth #1: debian is old software

Please, use testing or stable-backports. If you use debian stable your system will in fact be stable and that means: updates contain no new software but only fixes.

myth #2: debian is slow

We compile and build most of our packages with industry-standar compilers and options. I don’t see a significative difference on how fast linux kernel or mysql run in a CentOS or in Debian.

myth #3: debian is difficult

I already discussed about this issue back in Jan 2017, Debian is a puzzle: difficult.

myth #4: debian has no graphical environment

This is, simply put, false. We have gnome, kde, xfce and more. The basic debian installer ask you what do you want at install time.

myth #5: since debian isn’t commercial, the quality is poor

Did you know that most of our package developers are experts in their packages and in their upstream code? Not all, but most of them. Besides, many package developers get paid to do their debian job. Also, there are external companies which do indeed offer support for debian (see freexian for example).

myth #6: I don’t trust debian

Why? Did we do something to gain this status? If so, please let us know. You don’t trust how we build or configure our packages? You don’t trust how we work? Anyway, I’m sorry, you have to trust someone if you want to use any kind of computer. Supervising every single bit of your computer isn’t practical for you. Please trust us, we do our best.

myth #7: nobody uses debian

I don’t agree. Many people use debian. They even run debian in the International Space Station. Do you count derivatives, such as Ubuntu?

I believe this myth is just pointless, but some people out there really think nobody uses debian.

myth #8: debian uses systemd

Well, this is true. But you can run sysvinit if you want. I prefer and recommend systemd though :-)

myth #9: debian is only for servers

No. See myths #1, #2 and #4.

You may download my slides in PDF and in ODP format (only in spanish, sorry for english readers).

Jonathan Dowland: Residential IPv6 stability

11 May, 2017 - 23:16

I run some Internet services on my home Internet connection, mostly for myself but also for friends and family. The IPv4 address assigned to my home by my ISP (currently: BT Internet) is dynamic and changes from time to time. To get around this, I make use of a "dynamic dns" service: essentially, a web service that updates a hostname whenever my IP changes.

Since sometime last year I have also had an IPv6 address for my home connection: In fact, lots of them. There are more IPv6 addresses assigned to my home than there are IPv4 addresses on the entire Internet: 4,722,366,482,869,645,213,696 compared to 4,294,967,296 IPv4 addresses for the entire world (of which 3,706,452,992 are usable).

I am relatively new to IPv6 (despite having played with it on and off since around the year 2000). I was curious to find out how stable the IPv6 addresses are, compared to the IPv4 one. It turns out that it's very stable: I've had four IPv4 addresses since February this year, but my IPv6 allocation has not changed.

Norbert Preining: BachoTeX 2017

11 May, 2017 - 20:37

A week of typesetting, typography, bookbinding, bibliophily, not to forget long chats with good friends and loads of beer. That is BachoTeX, the best series of conferences I have ever been. This year BachoTeX was held for the 25th time, and was merged with the TUG Meeting for a firework of excellent presentations and long hours of brain storming, hacking, music making, dancing, and simply enjoying life!

And while it was a bit less relaxing for me than in the last years, mostly due to the presence of my little daughter who requested presence quite often, it is still the place to be during the Golden Week!

Of course I also gave a talk at BachoTeX about our latest changes in the upcoming TeX Live 2017 release: fmtutil and updmap – past & future changes (or: cleaning up the mess). Big thanks to my company Accelia Inc. for allowing me to attend the conference.

We arrived after a long trip, first via train and plane to Vienna, then two days break (including research with a colleague), followed by a night train ride to Warsaw and another train ride to Torun and a taxi ride to Bachotek. All in all far too long to be done with a 14 month old girl. Finally arrived we went directly to our hut and found it freezing. Fortunately we could organize a heater so that the rest of the week we didn’t have to live in 5-10 degrees

The second day brought already the traditional bonfire. After a small (for Polish standard) dinner we ignored the rain and met at the fireplace for BBQ, beer, and lots of live music.

The rain stopped during the bonfire, probably due to my horrible singing, and the following days we were blessed with sunshine and warmer temperatures. The forest sparked in all kinds of greens.

For our daughter the trip was a great experience – lots of wild play grounds, many other kids, and a lake she really wanted to go swimming in. Normally I go swimming there, but this year I had a bad cold so I refrained from it, and with me also our daughter, to her great disappointment.

Another day has passed, and the sunset lights up the beautiful lake Bachotek. I cannot imagine a better place for concentrated work paired with great relaxation!

During the days the temperatures were really nice, but the mornings were cold, and our morning walk to the breakfast place was quite chilly.

Ample coffee breaks and lunch breaks left us enough time to discuss new developments. But the single most important thing that brought people to talk a lot was the horrible internet connection, a big plus in BachoTeX (but as far as rumors go it might have been the last time with that advantage!).

The last evening we had a banquet honoring 25 years of BachoTeX, one of the oldest TeX conference. Live music and dancing, lots of good food and drinks, and outside the perfect evening atmosphere.

Too fast the time has passed and we had to return to Vienna, retracing the long trip. How far it may be, taking the burden to come from Japan is worth every drop of sweat, the time at BachoTeX is probably one of the most productive, and at the same time most relaxing for me.

Big thanks to all our Polish friends for organizing the event.

(photo by Frans Goddijn)

Jonathan Dowland: Hof3.java

11 May, 2017 - 15:45

Jonathan Dowland: Hof2.java

11 May, 2017 - 15:45

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