[shayief]

It doesn't use threads, but programs are still preemptable. Single event loop uses multiple event queues. Every program owns its own event queue and runs in separate V8 context.

V8 supports script interruption for contexts. Engine puts interrupt guard checks into every function and every loop. So its possible to interrupt context even in a middle of infinite loop.

Yes, system doesn't solve multicore balancing problem for applications automatically. The idea is that every app can use available cores on a machine similar to a fixed size thread pool. So it can manually schedule tasks for available cores.

Whats interesting, that this thread pool could provide transparent access to computing power on other physical machines. So this should be pretty scalable.

GC pauses. Yes, this is a problem, but it shouldn't corrupt any data. I think hardware interfaces should provide some kind of error checking mechanism with the option to retry transmission. Worst case - critical parts implemented in native code.

Another idea how to deal with GC pauses is to reserve one core specifically for V8 concurrent GC tasks for every other core. Additionally this core can take care of all interrupt handlers.