Changed structure of overview into two parts

README.md

@@ -6,7 +6,9 @@ systems class aimed at upper-level undergraduates and (in some cases)
 beginning graduate students. They are based on years of teaching such a course
 at the University of Wisconsin-Madison.
 
-## Initial Projects
+## C/Linux Projects
+
+### Initial Projects
 
 These projects are meant to get you warmed up with programming in the C/UNIX
 environment. None are meant to be particularly hard, but should be enough so
@@ -18,20 +20,33 @@ journey; you'll have to do more on your own to truly become proficient.
 
 * [Unix Utilities](https://github.com/remzi-arpacidusseau/ostep-projects/tree/master/initial-utilities)
 
-* [Intro To xv6](https://github.com/remzi-arpacidusseau/ostep-projects/tree/master/initial-xv6)
-
-
-
-## Processes
+### Processes and Scheduling
 
 * Shell 
 
+### Virtual Memory
 
-## Virtual Memory
+### File Systems
+
+### Distributed Systems
 
 
-## File Systems
+## Kernel Hacking Projects (xv6)
+
+These projects all are to be done inside the
+[xv6](https://pdos.csail.mit.edu/6.828/2017/xv6.html) kernel developed at
+MIT. Unlike the C/Linux projects, these give you direct experience inside a
+real, working operating system (albeit a simple one).
+
+### Initial Projects
+
+* [Intro To xv6](https://github.com/remzi-arpacidusseau/ostep-projects/tree/master/initial-xv6)
+
+### Processes and Scheduling
+
+### Virtual Memory
+
+### File Systems
 
 
-## Distributed Systems