https://hackaday.com/2023/08/27/linux-on-a-commodore-64/
> There is a catch (rather: a couple) of course: It runs extremely slowly and it needs a RAM Expansion Unit (REU), as there is no chance to fit it all into just 64KiB.
> It even emulates virtual memory with an MMU.
https://github.com/onnokort/semu-c64
https://hackaday.com/2023/08/27/linux-on-a-commodore-64/