> Large part of it is what task descriptor in the kernel takes. 4K for kernel stacks, only 2K with future work. That's really not much space at all if you're d

> Large part of it is what task descriptor in the kernel takes. 4K for kernel stacks, only 2K with future work. That's really not much space at all if you're doing anything interesting with those threads. > Also, if nothing else, you'll run out of PID numbers, as they're usually still 16 bits, even today Not for a very long time.