Trace Mode (Ctrl + t): Toggle Trace mode on or off. You may also start trace mode by clicking the trace toolbar icon.
In this mode, you can ‘play’ the DVD, simulating the execution of all the DVD’s commands. In Trace mode, a new sub-window is opened in the lower part of the interface as depicted below:
Trace is a very powerful debugging tool. The controls allow you to play, stop, watch registers and PUOs, set breakpoints (at PGCs or any or all of the registers), log the trace, enter values to registers and many other things. These are described below.