Consider the following statements about user level threads and kernel level threads.

Which one of the following statements is FALSE?

Consider three $$CPU$$-intensive process, which require $$10,20$$ and $$30$$ time units and arrive at times $$0,2$$ and $$6$$ respectively. How many context switches are needed if the operating system implements a shortest remaining time first scheduling algorithm? Do not count the context switches at time zero and at the end.

Consider the following statements with respect to user-level threads and kernel-supported threads.
i) Context switch is faster with kernel- supported threads
ii) For user-level threads, a system call can block the entire process
iii) Kernel-supported threads can be scheduled independently
iv) Use-level threads are transparent to the kernel

Which of the above statements are true?

Which of the following scheduling algorithms is non-preemptive?