TCP keepalive: what is it, why do you need it, how to configure it on #Linux

By | November 7, 2017

As you are aware, no service runs alone on some server. You always have to take into account the communication layer between your server and client services. One of the most tricky thing a lot of people overlook is the “housekeeping” of the communication layer. In a properly setup enterprise environment your communication layer (firewalls,… Read More »

#RaspberryPi python games for #Pimoroni Unicorn HAT HD

By | November 7, 2017

There are some nice demos that come with Pimoroni Unicorn HAT HD library but if you want something more fun you can have interactive applications. How about GAMES ? I stumbled over a thread Unicorn HAT Demo Ideas where someone was asking foe ideas of demos for the standard Unicorn HAT. Two of the best… Read More »

#RaspberryPi with #Pimoroni Unicorn HAT HD

By | October 21, 2017

This pumped up Pimoroni Unicorn HAT HD is an incredible toy. The content of the kit looks like the following: – a 256 RGB LED pixels in a 16×16 matrix. Pixels driven by ARM STM32F and three STP16CPC26 LED drivers – Bundled ninja diffuser – Nuts(4) and bolts (8 + 3 spares) I was able… Read More »

#RaspberryPi toys from #Pimoroni

By | October 21, 2017

Because this month is my Birthday like a true big kid I brought some toys. What better place to buy shiny and sparkling new toys can you find compared to Pimoroni ? The service was very fast and I really liked the presentation: So what is the content of the box and the reason for… Read More »

#Windows10 – set English language but with German keyboard layout

By | October 21, 2017

I have a nice mechanical keyboard “VicTsing® Mechanical PC Gaming Keyboard 87” with German layout, but I prefer my Windows 10 in English. The quick solution the use the keyboard was to add also German language support but kept English as default language. Then the most annoying and frustrating thing kept happening: 1. I selected… Read More »

Back-up of /home of a running system using lv snapshot

By | October 21, 2017

Following is a simple and easy way to do a consistent back-up of the /home directory (usually mounted in a separate partition) on a running system. We do not have the luxury of being able to stop the operations of a server and unmount the home partition to make sure no changes are done during… Read More »

Find in Linux if your installed RAM is ECC

By | October 21, 2017

Sometimes really simple questions are hard to answer. One day I got the question from a coworker: “How do I know if some installed RAM is ECC or not”. The easiest way is to use dmidecode command that dumps in Linux all the system characteristics. But because I had no idea how to see if… Read More »

#Docker : Fix services cannot see each other by name if they run on different swarm nodes issue

By | October 18, 2017

Lately after one of the updates of docker binaries I started to have a strange issue in a Docker Swarm setup configured here. Services were no longer able to see each other if they were running on different nodes. If two services were running on the same swarm node there was no issue. This is… Read More »

Having fun with #Conrad #RaspberryPi Advent Calendar – Days 1-5

By | October 20, 2017

In a perfect German tradition Conrad electronics shop released an Advent Calendar for Raspberry Pi. You can buy it online or from a Conrad shop if you get to go to Germany in a town with a Conrad shop. Got mine from the Conrad in Leipzig but online is available at Conrad Online There are… Read More »

#Oracle 12c invisible columns

By | February 20, 2021

“Invisible columns”: This is a new feature introduced in Oracle 12c that got me all excited.In short you can now have hidden columns in a table that are not visible to the standard SELECT, INSERT clauses if you do not want to. Some usage for this: Legacy application queries I hate how you have to… Read More »