What makes the kernel tick?

Linux is just a kernel, but as Jonni Bidwell discovers there’s an awful lot going on in there…

After being around for 30 years, let’s take a peek inside… Linux is just a kernel, but as Jonni Bidwell discovers there’s an awful lot going on in there.

Explaining what Linux is to senior management types can sometimes be tricky. An operating system, a monolithic kernel written in C, or a way of life are all valid answers. But so too is, to paraphrase Morpheus from The Matrix, “no one can tell you what Linux is, you have to experience it for yourself”. Fortunately, the fact you’re reading this magazine suggests you have some interest in Linux, maybe even some experience, and so we’ll treat you to a kernel deep-dive the likes of which would have management quaking in their boots.

The Linux Kernel is at the heart of all your favourite distros. It’s the interface between hardware and software, so it contains all the device drivers, networking stacks and weird protocols required to get your system from the BIOS into a usable state (via the bootloader), and hopefully keep it that way. It has direct access to the CPU and memory, so when userspace programs want to access those, they do so via kernel calls. The kernel then dutifully allocates memory, gets the CPU to do the required sums, and gives back the requested result.

Windows and macOS have kernels, too – it’s just that those kernels are much more tightly coupled with their respective OSes. Android uses the Linux Kernel, but buried deep beneath layers of Java-flavoured abstractions that make it utterly unlike a conventional Linux distribution. But enough about lesser OSes. We’re here to find out what makes the Linux kernel tick, how it has developed and even how to make it tick faster. So without further ado, on with the show!