Your linux kernel has many features which are not explained in the kernel source itself; these features are typically utilized through external packages. Some of the most common are listed here.
The linux console probably has more features than it deserves. Among these are the ability to switch fonts, remap your keyboard, switch video modes (in newer kernels), etc. The kbd package has programs which allow the user to do all of this, plus many fonts and keyboard maps for almost any keyboard, and is available from the same sites that carry the kernel source.
Rik Faith (faith@cs.unc.edu) put together a large collection of
linux utilities which are, by odd coincidence, called util-linux. These are
now maintained by Nicolai Langfeldt (util-linux@math.uio.no).
Available via
anonymous ftp from sunsite.unc.edu in /pub/Linux/system/Misc, it
contains programs such as setterm, rdev, and
ctrlaltdel, which are relevant to the kernel. As Rik says, do
not install without thinking; you do not need to install everything in
the package, and it could very well cause serious problems if you do.
As with many packages, this was once a kernel patch and support programs. The patches made it into the official kernel, and the programs to optimize and play with your hard disk are distributed separately.
gpm stands for general purpose mouse. This program allows you to cut and paste text between virtual consoles and do other things with a large variety of mouse types.