A rescue diskette set usually consists of two diskettes, which are booted from. When the boot is finished, a very small Linux system gives the user a shell prompt as root.
This feature is widely used to repair an existing, damaged, Linux system, since the rescue system doesn't depend on the hard disk to boot.
A rescue boot image usually comes with Linux CD's, and other images are available on the web. However, using a home-made rescue disk set is very beneficial in operating your particular computer. There are many other applications to booting from diskettes as well.
This lecture was planned so that the listener will be able to go home and create customized diskettes quite easily. The approach will be practical, where theoretical background will be given only where it's needed to understand what is done.
In some parts it's assumed that the listener is acquainted with LILO, and knows how to set it up. Lack of this knowledge won't disrupt the general understanding, but using LILO is part of creating your own diskettes.