The Deadlock Problem deadlock situation A set of blocked processes each holding a resource and waiting to acquire a resource held by another process in the set. Example 1 o System has 2 disk drives. o P and P2 each hold one disk drive and each needs another one. Example 2 Po P o semaphores A and B,initialized to 1 wait(A); wait(B) wait(B); wait(A) 0Q0 陈香兰(C5,U5TO Operating System OS原理与设计 March21,20196/45. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The Deadlock Problem deadlock situation A set of blocked processes each holding a resource and waiting to acquire a resource held by another process in the set. Example 1 System has 2 disk drives. P1 and P2 each hold one disk drive and each needs another one. Example 2 semaphores A and B, initialized to 1 P0 P1 wait (A); wait(B) wait (B); wait(A) 陈香兰 (CS, USTC) Operating System OS原理与设计 March 21, 2019 6 / 45