I'm going through the video tutorial about coordinate systems.  I can see that the narrator is presenting an older version of Mach 3.
I have the roadrunner code loaded, but I'm not seeing the same thing on the upper right display as I'm seeing in the tutorial.  One notable thing missing is the box showing the xy limits of the roadrunner tool path.  Another thing.  He has his machine coordinates set to 100mm x 100mm.  The roadrunner path is miniscule within these machine coordinates.  I have my machine coordinates set to 30" x 6", and the roadrunner path is 5 - 6" both directions.  I'm not sure why it's coming out so small in the tutorial.
Just trying to learn this stuff.  thanks

BTW, the box in the display around the tool path would be a great thing to have.  Is that a setting?

The extents is no longer part of the toolpath, you would find that on the  Toolpath page.

The roadrunner code does not have  either G20 or G21 in it so it will run at the default (or present) unit setting of your machine. The code however is sized in Imperial units so it really should have a G20 at the start so that Machs units would be set to Inch. Because it doesnt and the machine in the video you watched, was set as metric default then Mach treats the units as mm and thus it is tiny.

regarding the "box" I think what you are meaning is the bounding box showing your machines limits? If you have Softlimits set then pressing the Display button then Regen will toggle between Machine and Part displays. Machine will show your machines limits in the display.

Hood