Debian is a free operating system (OS) for your computer. An operating system is the set of basic programs and utilities that make your computer run. At the core of an operating system is the kernel. The kernel is the most fundamental program on the computer: It does all the basic housekeeping and lets you start other programs.

The kernel is a piece of software that, roughly speaking, provides a layer between the hardware and the application programs running on a computer. In a strict, computer-science sense, the term 'Linux' refers only to the kernel - the bit that Linus Torvalds wrote in the early 90s.

"The Linux kernel (the core of the Linux operating system) The kernel package contains the Linux kernel (vmlinuz), the core of any Linux operating system. The kernel handles the basic functions of the operating system: memory allocation, process allocation, device input and output, etc."

Ubuntu 9.04, the next Linux operating system release due out by Canonical in April, will not be shipping with the Linux 2.6.29 kernel like many had hoped for.

Somewhere between the debut of Ubuntu 9.10 (Karmic Koala for those into animal names) and today, the developers/maintainers/overlords of what many consider the leading Linux distribution have fixed the dreaded "kernel mode setting bug" that rendered the X Window system on many computers using Intel video hardware unusable until kernel mode setting was turned off.

You don't need a PhD in computer science and years of experience to hack the kernel. We asked prolific kernel hacker (and Linux Format reader!) Greg Kroah-Hartman to tell us what it takes for newbies to patch the Linux kernel - here's what he had to say...

The Linux world makes much of its community roots, but when it comes to developing the kernel of the operating system, it's less a case of "volunteers ahoy!" and more a case of "where's my pay?".

Have a look at Linux kernel source from a bird's eye view. The Linux kernel is one of the most mysterious open source projects. There is a lot of documentation, however it is still a difficult subject to comprehend. The Interactive Linux kernel map is intended to help people gain an overview of the structure and interactions of the Linux Kernel.

Linux kernel is the central component of Linux operating systems. It is responsible for managing the system's resources, the communication between hardware and software and security. Unfortunately, stock kernel is not secured out of box. There are some important Linux kernel patches to secure your box. They differ significantly.