Numerical Solved with Deadlock Detection Algorithm
Q3. Use deadlock algorithm, there are five processes and 3 resource type
A -> 7 instances
B -> 2 instances
C -> 6 instances
Process | Allocation | Request | Available | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Solu:
Step 1:
For process P0
request0 available
(0, 0, 0) ≤ (0, 0, 0)
Process P0 will execute.
Available = Available + Allocation
request1 ≤ available
(2, 0, 2) ≤ (0, 1, 0)
P1 must wait.
Step 3:
For process P2
request2 ≤ available
(0, 0, 0) ≤ (0, 1, 0)
P2 will execute.
Available = Available + Allocation
= (0, 1, 0) + (3, 0, 3)
= (3, 1, 3)
Step 4:
For process P3
request3 ≤ available
(1, 0, 0) ≤ (3, 1, 3)
P3 will execute.
Available = Available + Allocation
= (3, 1, 3) + (2, 1, 1)
= (5, 2, 4)
Step 5:
For process P4
request4 ≤ available
(0, 0, 2) ≤ (5, 2, 4)
P4 will execute.
Available = Available + Allocation
= (5, 2, 4) + (0, 0, 2)
= (5, 2, 6)
Step 6:
For process P1
request1 ≤ available
(2, 0, 1) ≤ (5, 2, 6)
P1 will execute.
Available = Available + Allocation
= (5, 2, 6) + (2, 0, 0)
= (7, 2, 6)
Safety sequence = <P0, P2, P3, P4, P1>