Grab the source, compile it and get it running...after that...whatever you find interesting. Some ideas:<p>* Trace the execution of one of the user land programs (e.g. ls) to see how it uses the syscalls.<p>* Add a new syscall - there are a few open-courseware labs online which have this as in introductory exercise (e.g <a href="http:&#x2F;&#x2F;moss.cs.iit.edu&#x2F;cs450&#x2F;assign01-xv6-syscall.html" rel="nofollow">http:&#x2F;&#x2F;moss.cs.iit.edu&#x2F;cs450&#x2F;assign01-xv6-syscall.html</a>)<p>* In a similar vein - find some other labs for other courses using this - and follow them.<p>* Read through the companion book (can be compiled from the source or downloaded pre-compiled) and follow it through the source code.