Yeah that's what I was thinking as well. The article leads with "The most commonly cited drawback of OS-level threads is that they use a lot of RAM." and that'

Yeah that's what I was thinking as well. The article leads with "The most commonly cited drawback of OS-level threads is that they use a lot of RAM." and that's not the impression I had at all. I've always felt that the biggest reasons that threadless concurrency primitives were adopted was to avoid the non-negligible cost of spawning threads and context switching between them.