"Kexec was originally intended for use by kernel and system
developers who had to reboot several times a day. Soon, system
administrators for high-availability servers found use for it as
well. As systems get more and more advanced, and boot times get
longer, end users can now benefit from it.
"The system is simple, and consists of two parts: a
kexec-enabled kernel and the kexec-tools package. Most modern
kernels already support kexec functionality, but I haven't found a
reliable way to test for kexec support in the kernel. My suggestion
is to try it -- if it works, you have it. If not, you may have to
compile a custom kernel to get it. As for the second part, you can
get the kexec-tools software either from your distribution's
repositories or from the kexec project page."