The “ATC” in the title is Air Traffic Control. You might wonder what Emacs has to do with air traffic control other than some engineer writing code for the system with Emacs. The truth is much stranger and surprising.
For a brief period of time, the Air Traffic Control system of the newly unified East and West Germany was running on Emacs. No, really. The German ATC system was running on an editor. The words don’t even seem to make sense.
I’ve heard this story before, but someone just posted a link to the story on the Emacs Wiki. As far as I can tell, I haven’t written about it before so I thought I’d share. The TL;DR is that after reunification, there was a huge project to combine the two countries’ ATC systems. An academic refugee from Symbolics was tasked to write the message router but didn’t know any languages other than Lisp. Being a “Herr Doktor” his word was unassailable but there was no Lisp on the system and no budget to buy one. There was, however, Emacs so Herr Doktor coded his message router in Elisp and for a little while airplanes over Germany were being controlled with the help of code running on Emacs. Proof that, as I always say, Emacs really is a Lisp Machine
It’s a truly amazing, not to say terrifying, story but the next time some VS Code partisan starts telling you how much better his editor is, ask him if it ever ran an ATC system.