6. Multi threading models - generally occurs by time-division multiplexing (as in multitasking): the processor switches between different threads.

• many-to-one model - maps many user-level threads to one kernel thread.
• one-to-one model - maps each user thread to a kernel thread. It provides mode concurrency than the many-to-one model by allowing another thread to run when a thread makes a blocking system call.
• many-to-many model -The many-to-many model multiplexes many user-level threads to a smaller or equal number of kernel threads. The number of kernel threads may be specific to either a particular application or a particular machine.