Last checked against version &kernel-contversion;. The linux kernel and the linux kernel headers The Linux kernel is at the core of every Linux system. It's what makes Linux tick. When a computer is turned on and boots a Linux system, the very first piece of Linux software that gets loaded is the kernel. The kernel initializes the system's hardware components such as serial ports, parallel ports, sound cards, network cards, IDE controllers, SCSI controllers and a lot more. In a nutshell the kernel makes the hardware available so that the software can run. These are the files we copy to /usr/include/{linux,asm} in chapter 5. They should match those which glibc was compiled against and so should not be replaced when upgrading the kernel. They are essential for compiling many programs.