Sure, so were save files for many older games, but it was a dump of the document / game state, which was a fraction of the running program, and probably designe

Sure, so were save files for many older games, but it was a dump of the document / game state, which was a fraction of the running program, and probably designed for that in mind in the first place. Image-based systems (smalltalk, self) would probably be a better model for a live tab, but it still requires things to line up.