Assume an operating system maps user-level threads to the kernel using the many-to-many model and the mapping is done through LWPs. Furthermore, the system allows developers to create real-time threads. Is it necessary to bind a real-time thread to an LWP? Explain.

Yes. Timing is crucial to real-time applications. If a thread is marked as real-time but is not bound to an LWP, the thread may have to wait to be attached to an LWP before running. Consider if a real-time thread is running (is attached to an LWP) and then proceeds to block (i.e. must perform I/O, has been preempted by a higher-priority real-time thread, is waiting for a mutual exclusion lock, etc.) While the real-time thread is blocked, the LWP it was attached to has been assigned to another thread. When the real-time thread has been scheduled to run again, it must first wait to be attached to an LWP. By binding an LWP to a real time thread you are ensuring the thread will be able to run with minimal delay once it is scheduled.