The Linux kernel is just a program
serversfor.dev
Most books and courses introduce Linux through shell commands, leaving the kernel as a mysterious black box doing magic behind the scenes. In this post, we will run some experiments to demystify it: the Linux kernel is just a binary that you can build and run.

I’ve been working on a “Linux Inside Out” series and wrote a post that might interest folks here who like low(ish)-level / OS internals.

The idea is to dissect the components of a Linux OS, layer by layer, and build a mental model of how everything fits together through experiments.

The first part is about the kernel, in the post I:

  • take the same kernel image my distro boots from /boot
  • boot it directly with QEMU (no distro, no init system)
  • watch it panic
  • write a tiny Go program and use it as PID 1
  • build a minimal initramfs around it so the kernel can actually start our process

The goal isn’t to build a real distro, just to give a concrete mental model of:

  • that the Linux kernel is just a compressed file, you can boot it
  • without anything else
  • what the kernel actually does at boot
  • how it hands control to userspace
  • what PID 1 / init is in practice
  • what is kernel space vs user space

Link: https://serversfor.dev/linux-inside-out/the-linux-kernel-is-just-a-program/

I’m the author, would be happy to hear from other devs whether this way of explaining things makes sense, and what you’d add or change for future posts in the series.

Hope you find it useful.