Upgrading to the 2.4.x kernel
The Linux kernel is the heart of the operating system. It is important that it is kept up to date and working properly for your system to work at its optimum potential. The stable 2.4.0 kernel is a conglomeration of patches and additions that have been made throughout the experimental 2.3.x series of the kernel.
Upgrading from 2.0.x to 2.2.x had been a tricky affair as many of the supporting tools had to be upgraded before the kernel could be compiled and booted into. Fortunately this time, the transition from 2.2.x to 2.4.x is simpler, assuming that your system was 2.2.x ready. Since the 2.4.x kernel is a hefty 23mb download, it would be worthwhile reading over the improvements and changes that have been made to the kernel to find out whether or not you really need it.
The biggest addition comes in the form of the much-publicized support for the Itanium, Intel's 64bit processor. While the processor itself is slated for release later this year, the present support allows users to easily migrate to a 64bit processor and take full advantage of the processor's architecture. For home users, the IA64 support doesn't mean much as it will take time for prices to come down and become affordable. Additionally, support for IBM S/390 systems has also been added.
PNP support for ISA devices has finally become stable. Also support for USB devices has been improved and PCMCIA/PC Card support has become mature. These may very well be some of the good reasons why you may want to upgrade the kernel.
As far as file systems are concerned, the inclusion of UDF will benefit DVD and CD-RW users. Don't get too excited though, as DVD video playback support under Linux still remains flaky. ReiserFS is available in the 2.4.1 kernel release but is having some stability problems.
Another good reason for upgrading to 2.4.x would be to make use of the highly improved networking core, which was optimized for speed and completely revised. The NFS code has been improved and should cause lesser headaches and it even supports the latest revision of NFS namely NFSv3.
One of the notable changes with this kernel is the inclusion of Device Filesystem or DevFS. Unlike the large list of device nodes in the /dev directory which point to the devices, DevFS cleans up some of the clutter by created device nodes on the fly when a specific driver is loaded. The structure of /dev will also change with device nodes placed inside different categories. DevFS is not installed by default.