Define deadlock and describe three methods for dealing with deadlock. A system has four processes P_1, P_2, P_3, P_4 and three types of dedicated resources R_1, R_2 R_3. The existence vector is E = (3, 2, 2). Process p_1 holds one unit of R_1 and requests one unit of R_2 Process p_2 holds two units of R_2 and requests two units of R_1 and one unit of R_3; Process p_3 holds one unit of R_1 and requests one unit of R_2; Process p_4 holds two units of and requests one unit of R_1. i. Compute the availability vector. ii. Explain whether the system is deadlocked. iii. Determine whether this state of the system is safe