Question 1. (4 points) A computer system has enough room to hold five programs in its main memory. These programs are ideal waiting for 1/0 half the time. What fraction of CPU time is wasted? Question 2. (4 points) A computer has 4 GB of RAM of which the operating system occupies 512 MB. The processes are all 256 MB (for simplicity) and have the same characteristics. If the goal is 99% CPU utilization, what is the maximum I/O wait that can be tolerated? Question 3. (4 points) Why creating and terminating a thread in an existing process can be much faster than creating and terminating a process? Question 4. (4 points) Assume that you are trying to download a large 2-GB file from the Internet. The file is available from a set of mirror servers, each of which can deliver a subset of the file's bytes; assume that a given request specifies the starting and ending bytes of the file. Explain how you might use threads to improve the download times. Question 5. (4 points) in Figure 2-8 in the textbook, a multithreaded Web server is shown. If the only way to read from a file is the normal blocking read system call, do you think user-levelthreads or kernel-level threads are being used for the Web server? Why