There are at least three theoretical implementations of userland threads in an Operating System: * 1:1, where each userland thread maps directly to a kernel th

There are at least three theoretical implementations of userland threads in an Operating System: * 1:1, where each userland thread maps directly to a kernel thread * 1:N, where several userland threads map directly to one kernel thread * M:N, where the kernel maintains a pool of threads and dispatches userland threads to them History has shown that 1:1 threading has the best trade offs. It's worth more independent research if you are interested in Operating Systems.