Concurrency and SMP are two very different things. One can have a kernel that handles concurrency better than anything else alive but it does not have any suppo

Concurrency and SMP are two very different things. One can have a kernel that handles concurrency better than anything else alive but it does not have any support for SMP. But ... I didn't say anything about BeOS in my comment? I was talking about Haiku, which has very different origins than BeOS, especially on the kernel front where the internal architecture was and is pretty different from the Be kernel. I actually don't know how much the Be kernel was designed for SMP from the first days; I think it was but I'm not sure. At any rate it definitely did have better concurrency for desktop usage than anything else at the time, I believe.