The event graph provides the viewer with a unique perspective on the flow of events in the system.
Every control modifiying event modifies the flow of the graph.
A vertical line marks a shift of control from or to the kernel. A horizontal line marks a time lap during which a process or the kernel was executing. Blue vertical lines are either an entry or an exit to a system call. Grey vertical lines mark entry of exit from a trap. White line mark entry or exit by way of interrupt.