Die wunderbare Welt von Isotopp

Fertig gelesen: Blue Machine

Kristian Köhntopp - September 26, 2023
Helen Czerski wrote a book. Blue Machine: How the ocean shapes our world occupies the weird space between memoir, travel blog and science outreach. In the middle of this she manages to explain the biggest machine on our planet: The collection of oceans in which the continents are embedded. But also the deep love of science, the desire to understand how our world functions, and the connection between all people than live on it.

Flugtaxi

Kristian Köhntopp - September 18, 2023
Golem schreibt: Über 2000 Skydrive-Lufttaxis vorbestellt . Das eVTOL Skydrive ist 13 x 13 Meter groß und 3 Meter hoch. Angetrieben wird es von zwölf Elektropropellern, die auf einem Gestell angebracht sind, ähnlich wie bei den Volocoptern. In dem eVTOL ist Platz für drei Personen: zwei Passagiere und eine, die es fliegt. Die Fluggeräte, die später ohne Pilot fliegen sollen, können auf einer relativ kleinen Fläche senkrecht starten und landen.

The Need for Smarter Clients

Kristian Köhntopp - September 18, 2023
Somebody asked me very politely on the Fedi: Would you please post all but the first post in a thread as “unlisted”? I like to follow you, but the sum of all posts by you takes up so much space on my front page. The answer to that request, also politely, is a firm “No.” Selection, ordering and presentation of posts is a client problem, which it has to solve, according to your configured preferences.

Kernfusion

Kristian Köhntopp - September 17, 2023
Heise schreibt: Kernfusion: Deutschland fehlt laut Studie eine Strategie . “Der Fusionsenergie könnte in den nächsten zehn bis fünfzehn Jahren der entscheidende Durchbruch gelingen, aber Deutschland schaut nur staunend oder skeptisch zu”, kritisierte von Tschirschky. Deutschland brauche eine Fusionsstrategie für sämtliche Schritte von Lieferketten über Forschungsförderung bis zu Verwaltungsvorschriften. Golem schreibt: Deutschland fehlt laut Studie eine Strategie dafür In zehn bis fünfzehn Jahren könnte die Technik für die Stromerzeugung einsatzfertig sein, meint die Unternehmensberatung Strategy&.

Haftungsfragen

Kristian Köhntopp - September 16, 2023
Die Niederlande halten es so: Aanrijding met voetganger of fietser . Wer haftet bei einem Unfall mit einem Fußgänger oder Radfahrer? Radfahrer oder Fußgänger gelten als schwächere Verkehrsteilnehmer. Da sie im Verkehr gefährdet sind, sieht das Gesetz eine besondere Regelung für Unfälle mit Kraftfahrzeugen vor. Abhängig vom Alter des Radfahrers ist der Eigentümer des Kraftfahrzeugs ganz oder teilweise für den Schaden des Radfahrers verantwortlich. Umgekehrt kann der Autofahrer den Schaden, den er aufgrund eines Fehlers eines Radfahrers oder Fußgängers erleidet, beim Radfahrer oder Fußgänger (oder seiner Haftpflichtversicherung) geltend machen.

sshpass

Kristian Köhntopp - September 15, 2023
Heute lernte ich, daß das Utility sshpass existiert. Ich habe das beim Lesen eines .gitlab.ci.yml Files gelernt. Und ihr wundert Euch, wieso Sysadmins alle Schwarz tragen und an Whisky interessiert sind. Was ist sshpass werdet ihr jetzt fragen? Und RedHat erklärt: The sshpass utility is designed to run SSH using the keyboard-interactive password authentication mode, but in a non-interactive way. Warum der Artikel jetzt nach und vor diesem Satz dann erklärt, wie man das benutzt, statt zu zeigen, warum man das nie braucht und wie man es ersetzt ist unklar.

Invalid-UTF8 vs the filesystem

Kristian Köhntopp - September 14, 2023
A UNIX filename can contain arbitrary bytes in an arbitrary sequence, with two exceptions: It cannot contain NUL (\0). It cannot contain slash (/), because that is the directory separator. But will all filesystems accept such filenames? And how will this work with languages such as Python, which require all strings to be valid utf-8 and which declare the filesystem interface to accept and return strings? A test program Let’s check.

Kein Homeoffice, keine Kekse

Kristian Köhntopp - September 12, 2023
Heise schreibt: Kommentar: Massenexodus bei Grindr – von den (Un-)Schönheiten des Homeoffice Ein Kommentar, der sich am Massenexodus bei Grindr abarbeitet, aber nicht weiß, was er will. Bei Grindr bildet sich eine Gewerkschaft, und viele Mitarbeiter werden Mitglied. Aus Rache führt die Firma Hybrid mit mindestens 2 Tagen pro Woche Anwesenheit ein. Daraufhin kündigen mehr als 50 % der Mitarbeiter. Der Artikel sieht das nicht als collective action der Mitarbeiter, sondern als eine Folge von Individualentscheidungen.

Der Admin-Beruf

Kristian Köhntopp - August 28, 2023
(based on a series of posts on Mastdon) Ein Heise-Artikel über Admin-Gehälter und ich schrieb dazu auf Mastodon: Ein hoffentlich aussterbender Beruf Der Beruf des “Admins” ist - hoffentlich - eine aussterbende Tätigkeit. Er wird zunehmend ersetzt durch die Kombination von Infrastrukturentwicklung und Support. Infrastrukturentwicklung befasst sich dabei mit der Automatisierung von Provisionierung, Konfiguration, Betrieb, Überwachung und Aktualisierung. Neben Kenntnissen über Betrieb sind auch Kenntnisse der Programmentwicklung notwendig. Mehr zu Devops in einem älteren Talk von mir.

Electric Cars and Numbers

Kristian Köhntopp - August 13, 2023
(based on a series of posts on Mastodon) I got an electric car I made the driving license late in life, in 1998 at the age of 30. My first car was a BMW 316i Coupe, used, 9000 Euro. I drove this until 2007. When I moved to Berlin, I found driving in the city inconvenient, and consequently used public transport. Eventually the battery of the car died from standing around, and I sold it.

Ubuntu: systemctl --user does not work

Kristian Köhntopp - July 12, 2023
Memo to self: I have a VPS with a legacy Ubuntu 20.04, and when creating a user to run a user-based service, trying to use systemctl fails with the message: $ systemctl --user status Failed to connect to bus: No such file or directory To solve this, multiple changes were necessary: Fixing the systemd problem The service is supposed to run as the user theservice, from the directory /home/theservice/therepo, and is to be controlled by a systemd instance for this user.

MySQL: InnoDB Fragmentation

Kristian Köhntopp - July 6, 2023
There is a really nice article by Pep Pla, over at the Percona blog about fragmentation in MySQL InnoDB tablespaces, which you should read. The article discusses “fragmentation” of data in tables, which happens in a way similar to how it happens in filesystems. InnoDB stores data by default in tablespaces, which by default are a file per table. These files are subject to the fragmentation and growth rules of your filesystem, but if you are smart, you are running MySQL on Linux on the XFS.

A Great Resignation, Management Edition

Kristian Köhntopp - June 22, 2023
This is not much of a blog post, but just a thread dump from Mastodon as requested by a friend, because my Mastodon posts expire after some time. Based on my work and the people I know, I have some (remote) view into what happens in a few companies at the C- and Mid-Level management. And from where I sit, it seems the great resignation is not only a thing that affects workers, but also managers.

What to do with self-driving car data?

Kristian Köhntopp - June 12, 2023
This is what a self-driving car sees, or constructs from the sensor data it uses: Screenshot from How is LiDAR remote sensing used for Autonomous vehicles? Specifically, LIDAR data is supposed to be extremely accurate and fast, Lidar Data Accuracy claims 2-3cm resolution and many scans per second for aircraft LIDAR, and Assessing Vehicle Profiling Accuracy of Handheld LiDAR claims similar resolution for casual LIDARing crash scenes with Apple handheld hardware.

Getting rid of phishing training mails

Kristian Köhntopp - May 23, 2023
Just like your work computer is being infested with corporate malware as to prevent it from being taken over from other people’s malware, your account is also being spammed with corporate malware spam as to prevent it from being taken over by other malware spam. And just like corporate malware increases your machine’s attack surface , because it is badly written and running with privileges, corporate spam is a useless nuisance that doesn’t do what it is supposed to do .

50 years in filesystems: towards 2004 – LFS

Kristian Köhntopp - May 17, 2023
This is part 5 of a series. “1974 ” on the traditional Unix Filesystem. “1984 ” on the BSD Fast File System. “1994 ” on SGI XFS. “Vnodes ” on how to have multiple filesystems in Unix. Progress is sometimes hard to see, especially when you have been part of it or otherwise lived through it. Often, it is easier to see by comparing modern educational material and the problems discussed with older material.

50 years in filesystems: A detour on vnodes

Kristian Köhntopp - May 15, 2023
This is part 4 of a series. “1974 ” on the traditional Unix Filesystem. “1984 ” on the BSD Fast File System. “1994 ” on SGI XFS. Progress is sometimes hard to see, especially when you have been part of it or otherwise lived through it. Often, it is easier to see by comparing modern educational material and the problems discussed with older material. Or look for the research papers and sources that fueled the change.

50 years in filesystems: 1994

Kristian Köhntopp - May 12, 2023
This is part 3 of a series. The first part is “1974 ”. The second part is “1984 ”. Progress is sometimes hard to see, especially when you have been part of it or otherwise lived through it. Often, it is easier to see if you compare modern educational material, and the problems discussed with older material. And then look for the research papers and sources that fueled the change.

City of Amsterdam and Combustion Engines

Kristian Köhntopp - May 11, 2023
Electrive.net had an article about Copenhagen banning combustion engines in the city, starting 2030: (Article in German ). So I had to check what is the current state in Amsterdam. Current state The Netherlands has a central register for license plates. It is public, and anyone can check. There are many places that allow you to do that for car, not owner data. For example . The city of Amsterdam also allows you to check if a given license plate is allowed to enter the cities milieuzone.

It's a Modulith

Kristian Köhntopp - May 10, 2023
“Computers are simple” is what I am telling people I train. “There are only Zeroes and Ones, and it is not getting much more complicated.” “But computers are hard”, they respond. “That is correct. In computer systems, complexity is almost never in the individual layers, but it comes from the width and breadth of the stack. It’s in the interactions of the components that we are putting together.” When you start with how a CPU is being built, and then put the layers of the stack on top of each other until you end up with a classical single-process application, in some object-oriented language, with a GUI – that’s around two to three dozen layers of abstractions piled on top of each other.