Answer all questions

a. [10] Can a single process be blocked for three I/O events at a time? If no, justify in one sentence. If yes, give an example.

b. [10] Suppose a process has three user-level threads. One of the threads is blocked for I/O. What is the maximum number of CPUs (assuming we have a multi-CPU system) that this process uses in that case (i.e. while its thread is blocked)? Justify your answer.

c. [10] Can a process cause another blocked process to move from blocked state to running state? If no, justify in one sentence. If yes, given an example. [Assume threestate model]

d. [10] Does a process need to make a system call each time it needs to access any hardware in the system? If yes, state your reasons in 1-2 sentences. If no, given an example.

e. [10] Suppose we use a two-state model for a process (not running, running). State a scenario that shows why this two-state model is bad