"I was running SUSE Linux 9.0 on an IBM ThinkPad. This
configuration did everything I needed: word processing, Web access,
email, C and assembly programming. But my version of the Linux
kernel was out of date and I wanted to upgrade it. I wanted to do
this in a way that did not remove my current kernel, in case I
needed to revert to it.
"This article describes how I accomplished this task by using a
dual-boot system with two Linux kernels to choose from during
startup. You can use this same approach to upgrade to a new, stable
version of the kernel or to test a potentially unstable kernel
before committing to it..."