When to Recompile

Fedora systems use a modified version of the plain vanilla Linux kernel (a modified version is referred to as a patched kernel) with additional drivers and other special features compiled into it.

Fedora has quite an intensive testing period for all distribution kernels and regularly distributes updated versions. The supplied Fedora kernel is compiled with as many modules as possible to provide as much flexibility as possible. A running kernel can be further tuned with the sysctl program, which enables direct access to a running kernel and permits some kernel parameters to be changed. As a result of this extensive testing, configurability, and modularity, the precompiled Fedora kernel does everything most users need it to do. Most users only need to recompile the kernel to

• Accommodate an esoteric piece of new hardware

• Conduct a system update when Fedora has not yet provided precompiled kernels

• Experiment with the system capabilities

Fedora supplies several precompiled versions of the kernel for Athlon and Pentium processors, for single- and multi-processor motherboards, and for enterprise-class systems (higher security; uses 4GB of memory). These kernel versions are provided in RPM format. Installing them is as easy as

# rpm -Uvh new_kernel.rpm

The kernel (but not the source) RPM files include installation scripts that automatically alter your bootloader configuration, making the new kernel the default. If you do not want that to happen, just manually edit the /etc/lilo.conf or /boot/grub/grub.conf files and change them back.

Caution

You should always rpm -U (upgrade) a new kernel rpm, rather than rpm -i (install), to avoid overwriting the old, but still working, kernel. This is done as a safety measure. What if the new one does not work?