The Linux kernel
The Linux kernel is a Unix-like operating system kernel created by Linus Torvalds 1991. It was originally developed for 32-bit x86-based PCs, but today, Linux also supports a large set of architectures such as ARM, PowerPC, MIPS, and SPARC. The Linux kernel is a fundamental part of a Linux distribution (such as Ubuntu, Debian, and Fedora).
When deciding which kernel is most suited to your project, it's good to have in mind how kernel releases work. Depending on your needs, you can choose between mainline, developing, or stable kernels. If you don't work with kernel development, it's recommended to avoid using the mainline kernel since it's still under development and is considered unstable. A kernel is always considered stable directly after it has been released from the mainline tree. After that, the kernel will be maintained until the next mainline kernel becomes available (usually in 2-3 months). However, a kernel can be picked as a longterm kernel...
