Duplicate window display on 2 screens with X.org

As an engineering school teacher and technical lecturer, I’m often asked to give demonstrations, in addition to the classic slide show. Like any organized lecturer, I can’t do without my notes, elapsed time, etc., which are given to me by presenter screen software. This kind of software requires an extended display, i.e. the computer screen and the video projector display 2 different things. The disadvantage of demonstrations is that the application window you want to show cannot be displayed on both screens at the same time. [Read More]

Gamification of a Linux system administration course

Gamification of a Linux system administration course
System administration isn’t something that’s obvious to everyone, and it’s a subject that, when it’s more to do with the basics of networking and Linux, can seem a lot more daunting than learning about the latest trendy technologies (Docker, Terraform, Kubernetes, etc.). Also, with the bombardment of information and easy access to computer content and tutorials often more interesting than “classic” lectures, students are less and less attentive, present or participating. [Read More]

Slow memhog for testing cgroups

Testing the cgroup memory is not something as easy as we can think. It can’t be only question of malloc(100000) in a loop, as the Linux kernel overcommit memory allocation: so even if we get effectively a 100000 bytes long memory space, this doesn’t decrease the physical available memory. To do so, this space need to be changed pages by pages, that can be tedious to do. And quite uncertain, because the kernel can take advantage of the swap partition… [Read More]