> they had version control that tracked all changes everywhere at all times, even changes that were not saved in any file. No. The file system did auto-versio

> they had version control that tracked all changes everywhere at all times, even changes that were not saved in any file. No. The file system did auto-versioning, so you could generally recover recent history of a file, but there was nothing that "tracked all changes everywhere". Well, ZMacs (the editor) did have unbounded 'undo' functionality, and you could even select a function and undo changes to that particular function, even if those weren't the most recent changes to the file. Maybe that's what you have in mind.