1.4. The Kernel

The kernel, the heart of the operating system, implements control over the memory and other computer's resources. The kernel also handles access to various hardware components of the system. For example, until version 2.4 of the kernel was introduced, the only Universal Serial Bus (USB) devices that Linux supported were the keyboard and mouse. But starting with version 2.4, Linux supports USB video cameras , printers, and other devices.

The Linux kernel version is designated using three numbers as follows :

The first number indicates significant kernel changes.
The second number indicates slight changes. This number tells whether the kernel is stable or is intended for testing purposes only and may contain errors. An even number means that the kernel has undergone thorough testing and is stable. An odd number means that the kernel version is in the testing stage and stable operation is not guaranteed .
The build number indicates the release version.

You have to update the kernel yourself, which gives your system new capabilities. Updating to an unstable kernel version, you can take part in its testing. New kernel versions can be downloaded from the www.kernel.org site or from the site of the developer of your distribution package.

Updating the kernel not only will give your machine new capabilities for using the hardware components but also will correct errors, which are part of all software, no matter how well tested . It can even increase the efficiency of your system. The most important thing is that you do not have to reconfigure the entire operating system to update the Linux kernel, as is done in some operating systems. I have seen computers whose operating systems were configured just as they had been when they were installed several years ago, with only the kernel and application programs being updated as needed. This is an exception rather than a rule. Usually, the system's hardware has to be upgraded every year or two to increase the performance and thus satisfy the ever-increasing demands of users and new resource-hungry software.