The total amount of available resources before any program runs is A: 2, B: 12,

Question

The total amount of available resources before any program runs is A: 2, B: 12, C: 9

Allocation

     A B C
P0 0 0 1
P1 0 0 0
P2 1 3 3
P3 0 4 3

Max

     A B C
P0 0 0 1     
P1 1 7 5    
P2 2 3 5     
P3 2 9 9    

Answer the following questions using the banker’s algorithm:
   (Must show work for credit!!)

1. Is the state of the system safe or unsafe? Explain or show a safe sequence.

2. Could a request of p1 for the additional resources of (0, 5, 2) be granted and still maintain the system in a safe state? Explain or show a safe sequence.

3. What is the state of the system if a request of p3 for (0, 5, 1) is granted instead? Explain or show a safe sequence.

Explanation / Answer

P0 executes as Need <Available , Available = Available + Allocation = [2 12 10]

P1 executes as Need <Available , Available = Available + Allocation = [2 12 10]

P2 executes as Need <Available , Available = Available + Allocation = [3 15 13]

P3 executes as Need <Available , Available = Available + Allocation = [3 19 16]

So system is in safe state and safe sequence is <P0,P1,P2,P3>

2.

Need of P1 = [1 12 7] now and avaiable is [2 12 10] so it can be executed safely as Need <Available. the safe sequence will be the same<P0,P1,P2,P3>

3.

Need of P3 = [0 5 3] can be easily fulfilled by Avaialble as Available > Need. The safe sequence is same P0,P1,P2,P3>

Process ALLOCATION MAX NEED = MAX-ALLOCATION A B C A B C A B C A B C 2 12 9 P0 0 0 1 0 0 1 0 0 0 P1 0 0 0 1 7 5 1 7 5 P2 1 3 3 2 3 5 1 0 2 P3 0 4 3 2 9 9 2 5 6

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