16. State Transitions by p 1 Process S 0 S 1 S 2 S 3 The state transition diagram described below is not complete . The actual number of states depends on possible operations of processes. R p 1 p 2 R p 1 p 2 R p 1 p 2 R p 1 p 2 Request R (by p 1 ) Acquire R (by p 1 ) Release R (by p 1 )
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19. Example p 1 and p 2 both need R 1 and R 2 . R 1 R 2 p 1 p 2 p1: Request( R1 ); Request( R2 ); Release( R2 ); Release( R1 ); p2: Request( R2 ); Request( R1 ); Release( R1 ); Release( R2 );
61. The Banker’s Algorithm Which of the requests can safely be granted ? Can p 1 R 1 be safely be granted ? Can p 2 R 1 be safely be granted ? Can p 3 R 1 be safely be granted ? R 1 R 2 p 1 p 2 p 3
62. The Banker’s Algorithm Can p 1 R 1 be safely be granted ? Can p 2 R 1 be safely be granted ? Can p 3 R 1 be safely be granted ? Temporarily grant Can such an RAG be completely reducible? R 1 R 2 p 1 p 2 p 3
63. The Banker’s Algorithm Can p 1 R 1 be safely be granted ? Can p 2 R 1 be safely be granted ? Can p 3 R 1 be safely be granted ? p 1 p 2 p 3 Temporarily grant Can such an RAG be completely reducible? R 1 R 2
64. The Banker’s Algorithm Can p 1 R 1 be safely be granted ? Can p 2 R 1 be safely be granted ? Can p 3 R 1 be safely be granted ? granted Can such an RAG be completely reducible? R 1 R 2 p 1 p 2 p 3
65. The Banker’s Algorithm Can p 1 R 1 be safely be granted ? Can p 2 R 1 be safely be granted ? Can p 3 R 1 be safely be granted ? R 1 R 2 p 1 p 2 p 3
66. The Banker’s Algorithm Can p 1 R 1 be safely be granted ? Can p 2 R 1 be safely be granted ? Can p 3 R 1 be safely be granted ? Can such an RAG be completely reducible? Temporarily grant R 1 R 2 p 1 p 2 p 3
67. The Banker’s Algorithm Can p 1 R 1 be safely be granted ? Can p 2 R 1 be safely be granted ? Can p 3 R 1 be safely be granted ? not granted R 1 R 2 p 1 p 2 p 3
68. The Banker’s Algorithm Can p 1 R 1 be safely be granted ? Can p 2 R 1 be safely be granted ? Can p 3 R 1 be safely be granted ? R 1 R 2 p 1 p 2 p 3
69. The Banker’s Algorithm Can p 1 R 1 be safely be granted ? Can p 2 R 1 be safely be granted ? Can p 3 R 1 be safely be granted ? Can such an RAG be completely reducible? Temporarily grant R 1 R 2 p 1 p 2 p 3
70. The Banker’s Algorithm Can p 1 R 1 be safely be granted ? Can p 2 R 1 be safely be granted ? Can p 3 R 1 be safely be granted ? p 1 p 2 p 3 Can such an RAG be completely reducible? Temporarily grant R 1 R 2
71. The Banker’s Algorithm Can p 1 R 1 be safely be granted ? Can p 2 R 1 be safely be granted ? Can p 3 R 1 be safely be granted ? granted p 1 p 2 p 3 R 1 R 2