Ask HN: What is the oldest, still supported OS?
The oldest one I know is PDP-11. It's still being used in nuclear power plants and many plants will continue using it until at least 2050 (maybe even longer if they remain working). [1] PDP-11 was released in 1970 so your TSOS find is even older. I'm sure there's something even older than these two that's being used by various gov orgs and industrial systems. There's plenty of small consulting firms that support ancient systems. These contracts provide them with steady and stable income.<p>[1] <a href="https://www.theregister.co.uk/2013/06/19/nuke_plants_to_keep_pdp11_until_2050/" rel="nofollow">https://www.theregister.co.uk/2013/06/19/nuke_plants_to_keep...</a>