VisualOS is a "visual simulator of an operating system", that will help
study and understand the way a real systems work.

It allows the user to insert processes in the running system, assigning them
properties (memory usage, processing bursts, IO accesses) and VisualOS will
dynamically show different graphical representations of each subsystem. It is
also possible to select the algorithm to be used in each case.

WWW: http://visualos.sourceforge.net/