Die wunderbare Welt von Isotopp

Plugs with Wi-Fi

Kristian Köhntopp - May 12, 2020
So we are baking bread, and for that we have a Wiesheu minimat oven that comes in at a full 16A - supposedly it is using 3kW or more peak plus the condenser hood that comes in at another 500W top power draw. On the other hand, when running the thing is hardly lukewarm, it is running much cooler than the Neff household oven/microwave combo we have. Wiesheu minimat with condenser hood.

Data Access Programs and Pre-SQL systems

Kristian Köhntopp - May 1, 2020
Let’s have a look at very old database systems. Things like dBase or compatible systems (“xBases”) allowed to manipulate record based files (with indexes) in a procedural way. What does that mean? xBase The system allows developers to create files that contain a well defined (fixed size) record structure, basically an array of struct on disk, often together with the definition of on-screen masks designed to show a single record and a (searchable) list of records.

Fertig gelesen: Deathworlders

Kristian Köhntopp - May 1, 2020
In the foreword to his short story “With Friends Like These" , Alan Dean Foster writes HFY? My favorite writer of science fiction was, and still is, the inimitable Eric Frank Russell. When I was turning in short stories to the magazines instead of papers to my college professors and collecting rejection slips instead of credits and grades, I often wondered why Russell had stopped writing. I miss him.

Fertig gelesen: Delta-V and Space Barons

Kristian Köhntopp - May 1, 2020
A lot of super rich people are currently busy blowing their money into space. Who are these people, and what drives them? Space Barons , Christian Davenport, 10.99 Eur (Kindle) In Space Barons, Christian Davenport goes through the rather short list of super rich men who are trying to get private spacecraft flying, tells their history, successes and failures, and their motivations - or, in some cases, the story of the death of their dreams and how they drop out of the second, private space race.

Fertig gelesen: Die Krone der Sterne: Hexenmacht/Maschinengötter

Kristian Köhntopp - May 1, 2020
“Hexenmacht” (German Edition) and “Maschinengötter” (German Edition) are part 2 and 3 in the series “Die Krone der Sterne” (The Crown of Stars) by Kai Meyer. See Die Krone der Sterne for a review of part 1. Hexenmacht , Kai Meyer, 12.99 Eur (Kindle) Where part 1 spent a lot of time with world building and tourism, showing of the wonder and the atmosphere of the universe, part 2 is approaching from a different angle - we get a lot more action, and a lot less background.

Netflix does not bring down the Internet

Kristian Köhntopp - March 19, 2020
It’s Coronavirus Crisis and Netflix is killing us all, again. This time it’s not their excessive energy use , but their dreaded HD videos that are overloading the Internet. Or is it? It’s only Swisscom Supposedly Switzerland is considering Netflix shutdown to prevent Home Office workers from being disconnected. According to its own statements, on the first day of the quasi curfew in our neighboring country, Swisscom recorded an enormous increase in the load on the infrastructure.

The lack of developer centric MySQL monitoring - a rant

Kristian Köhntopp - March 18, 2020
So where I work we have a large number of MySQL instances. They are organized in a slightly smaller number of replication hierarchies, which tend to cross region boundaries. Structure of a large database setup A rough sketch of the setup we have. Variants of this exist in various sizes - from 6 replicas in 3 regions to hundreds of replicas per region, with Group Replication at the top and per Region Intermedia Master.


Kristian Köhntopp - March 9, 2020
“Normalitär”, ein Begriff, der von @beimwort geprägt wurde. Nach einem Twitter Thread . In seinem Artikel auf T-Online propagiert Schaible eine Bruchlinie innerhalb der “rechten” Parteien, weil Teile der Mitglieder die Weltbildverschiebung der frühen 2000er mitgemacht haben, andere sie ablehnen. Er beschreibt die Welt von 1990, die Nachwendezeit: Vergewaltigung in der Ehe nicht strafbar, Diercke Weltatlas redet von Menschenrassen, unter den 250 Positionen der politischen Elite in Deutschland war nur eine Frau; alles weiße, angeblich heterosexuelle und angeblich christliche Männer.

Sonos recycled their recycle mode

Kristian Köhntopp - March 6, 2020
So I wrote about the Sonos Recycle Program before Sonos announced their plans to actively discontinue support for their older Speakers. Back then, the program did make sense, because it was kind of voluntary and avoided sending stuff back to Sonos for a Trade-Up. Even then, people disliked it. Then Sonos announced that they would discontinue support for these devices and it’s basically ‘you brick them now, or we are going to brick them for you in May and without a rebate for new equipment’.

Some latency numbers illustrated

Kristian Köhntopp - February 28, 2020
These images are older than time itself. I picked them up while working as a consultant for MySQL AB, but I do not know the source. Here are some important latency numbers. A pixel is a nanosecond (nano = 10^-9, a billionth of a second, 1 billion events/s = 1 GHz): And below is the HDD disk seek latency in full at the same scale. An uncached index access can result in up to 5 disk seeks, worst case.

In which we cycle shopping...

Kristian Köhntopp - February 22, 2020
Welcome to the Netherlands. Please excuse me, I need to fetch a few things before I have time for you. I need a few things from Lidl in Hoofddorp, do you want to come with me? It’s not far, we are taking the bike for some six kilometres. Also, I’m going to show you a trick: Look, Mom! Not riding with the cars, and no lights. Let’s follow path and go down Liniepad.

Under the sea...

Kristian Köhntopp - February 21, 2020
Welcome to the Netherlands. I am living at the bottom of a lake, 3.50 meters below the sea level, and there are sea shells in my garden. When I dig in my garden, it looks like this. The Netherlands (low lands) or Holland (hollow lands) are formed in large part by the Rhine Delta . This is an estuary delta (tidal delta), which means it is formed as much by erosion as it is formed by sedimentation.

How to build a cycling environment

Kristian Köhntopp - February 19, 2020
Welcome to the Netherlands. We’re building roads differently. They are better, safer and less stressful for cyclists, and that also makes them better, safer and less stressful for motorists. Here is how it works: (based on a Twitter Thread ) What does it look like? I am living in a village. That means a speed limit of 30 km/h inside the city limits, and that is being enforced by the design of the road.

Mein Sohn sitzt vor dem Computer

Kristian Köhntopp - January 28, 2020
Oliver Rautenberg berichtet auf Twitter von “Elternvereinbarungen zur Smartphone- und Mediennutzung” an Waldorfschulen in Deutschland. »Medienvertrag einer “Freien Schule” der Waldorfpädagogik. Ist diese Einmischung noch vertretbar? Keine Handys in der Schule, ok. Aber auch zuhause will die Schule Handys, Computer, Filme und sogar Hörspiele vertraglich verbieten. “Risiken und Gefahren” drohen!« Dies ist meine persönliche Erfahrung, also eine Studie mit einer Sample-Gruppe von n=1. Keine Ahnung, und mir egal wie Ihr Dinge bei Euch in der Familie regelt, aber vielleicht ist das ja dennoch für irgendwen nützlich.

Some rules for primary keys

Kristian Köhntopp - January 28, 2020
On Twitter, @CaptainEyesight asked a question: »Database architecture question: For deleting records, instead of a DELETE, UPDATE the id to the negative (i.e. 1 becomes -1) and then add AND id > 0 to every query. Great idea? or Greatest idea?« I was honestly a bit confused, because this idea is so weird that I took this question for a joke. But then I decided that this is a case for XKCD 1053 : »You are one of today’s lucky 10.

Mailbox.org, Google, OAuth und Less Secure Applications

Kristian Köhntopp - January 17, 2020
Heise schreibt in Mailbox.org: Google sperrt “unsichere” Dritte vom Kalender aus über Anwendungen von Dritten und den Zugriff auf Google Kalender, Google Mail und andere Dienste, die mit GSuite interagieren. Der Artikel wirft leider eine Reihe von Dingen durcheinander, was schade ist, weil er einen wichtigen Punkt machen will. OAuth2 vs. LSA Im Artikel geht es um OAuth2 . OAuth2 ist kein neues Verfahren. Es handelt sich um einen Standard, bei dem ein Dienstleister Drittanwendungen den Zugriff auf Dienste erlaubt, indem er der Drittanwendung relativ automatisch ein Logintoken zuteilt, das

Rolling back a rollout

Kristian Köhntopp - January 17, 2020
Florian Haas asks on Twitter : “How do you solve reliable rollback. The definition of a reliable rollback being: ‘get reset –hard ’, ‘git push -f’ and then magic happening that returns your infra to the exact state it was at .” The problem is relatively easy to solve with modern infrastructure-as-code for anything that is stateless. It becomes a bit more involved when you are dealing with things with state, such as database instances or Zookeepers or similar things.

Disable Saitek X.52 pro Clutch Mode

Kristian Köhntopp - January 15, 2020
This post is a memo to self, and describes how to disable the X.52 clutch mode. I am flying with a Saitek/Logitech X.52 pro HOTAS , and this stick has a ‘clutch button’ (labelled “i”) in the thumb position of the throttle (image: clutch highlighed in red) “Clutch mode” for this button means that it is usable as a modfier for the other buttons, when pressed together with a second button.

Sonos Recycle Mode

Kristian Köhntopp - December 30, 2019
Sonos is a company that makes Wi-Fi Connected speakers. They offer acceptable sound quality and an extremely good user experience. They also so far have never cancelled support for any of their speakers. Hardware Lineup and Timeline Some of their speakers are now qualified for a Trade-Up program, in particular their Play:5 (1st generation) speaker, the Connect:Amp and the Connect. The latter two (the Connect products) are somewhat obsolete as they were necessary when normal Wi-Fi was usually not able to carry sound data at the required reliability, so Sonos speakers built their own Wi-Fi Mesh network separately from the usual home Wi-Fi.

Streaming and Energy

Kristian Köhntopp - December 28, 2019
A bunch of boomers in Germany is running a distraction campaign on the energy use of data centers and streaming. Example articles in german language can be found in Zeit and Bento , but there is a larger series of articles acrooss multiple newspapers. A better structured reasoning can be found in SRF (German), and it highlights how arbitrary and wrong the energy numbers in the former articles are. But even this article ignores the facts that the energy consumption in a typical cloud data center is most likely carbon neutral, because the power used is likely to be completely green.