Comment by jjuran

> At this point, they could likely decompile MacOS classic and rework it to give it modern memory protection, virtual memory, preemptive multitasking, and networking.

You'd lose compatibility with the applications, though, so you'd have to decompile and rework those as well. And even if you did, you couldn't legally distribute any of it.

An alternative approach is high-level emulation. Running a separate instance per application gives you process isolation (via the host OS) for free.

> I assume booting an OS with a mere few megabytes of RAM footprint would only take milliseconds?

I haven't measured it as such, but yes.