If you're referring to the diagram outside the building, I think it might be telling you how to safely descend a long drop when you encounter one (or maybe it doesn't mean anything- I'm not super sure). As for the calculator (assuming you mean the one on the wall), try punching in the same thing that started the game in the first place. Lastly, I've never found any way to access syscalls.txt- I'm pretty sure it's just for show.
