Inside Linux.

This article provides a comprehensive overview of the Linux operating system, with a focus on the Linux kernel and its various subsystems and layers. It explains the different types of kernel designs and discusses the different versions of the Linux kernel and their support timelines. The article also covers topics such as maintaining compatibility with userspace interfaces, the use of drivers and modules in Linux distros, and boot options. Additionally, it introduces other kernels like BSD and GNU Hurd, and provides instructions for activities like controlling LEDs and compiling a kernel. The article includes information on key figures in kernel development and provides links to further resources for exploration. [Extracted from the article]