UUID and kickstart

[Ed Brown]

A universal identifier can be used in various contexts, to identify 
different kinds of devices for example.  This page I think answers 
your other questions:

http://syslinux.zytor.com/pxe.php

To make your life easier, if you're setting up a kickstart/PXE 
environment for the first time, you probably should check out:

https://fedorahosted.org/cobbler/wiki/CobblerLiveCd

-Ed