Task: Complete the following problems from or related to those of Chapter 1 . Each problem is 4 points unless noted. Give your interpretation of the kernel mode's role in the view of the OS as an extended machine and as a resource 1. manager. Do the same for user mode. Consider a system with two CPUs, each of which can service two threads with hyperthreading. Assume the threads that may be executing do not interfere with each other's execution and that all threads in this problem are 100% CPU-bound, do not block during execution, and do not change CPUs once assigned. 2. Suppose there are four single-threaded programs P0, P1, P2, and P3, with run times of 5, 10, 15,20 msec, respectively. They all start at the same time. What are the possible run times for the collection? (That is, when will they finish?) Consider a computer that has two levels of cache (L1 and L2), a main memory (RAM), a disk, and the OS uses virtual memory (for the purposes of this problem, it means that if a word is not found in cache or RAM, then it's 3. found on disk). It takes 1 nsec to access the word from L1,2 nsec from L2,10 nsec from RAM, and 7msec from disk. L1 hit rate is 90%. L2 hit rate is 95%. Main memory hit rate is 99%. What is the average time to access a word? A file whose file descriptor is fd contains the following sequence of bytes: 31415934211385321