=== Other Operating Systems ===
==== QNX ==== http://www.qnx.com
QNX (and, more recently, Neutrino) is a commercially available microkernel. It features a message passing kernel, and its architectural papers influenced VSTa's author greatly.
==== Plan 9 ==== http://www.fywss.com/plan9/
Plan 9 is an iteration of the OS design concepts first applied to design UNIX. Its filesystem view of system services is also present in VSTa.
==== Patrick Bridges' OS Page ==== http://www.cs.arizona.edu/people/bridges/oses.html
A large index and survey of operating systems.