@mei @mos_8502 I wonder if some 8-bit equivalent of WASM would work here for verifying that programs don't access memory they're not supposed to.

@mei @mos_8502 You can do multitasking just fine without an MMU, you just have to trust the programs not to poke addresses they're not supposed to. This is the approach taken by 68k macs. The main thing you need is code that is position independent, something that 6502 isn't really designed for especially since zero page and stack are fixed addresses. But I think the 816 is a bit more flexible, and ez80 probably more flexible still.