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
P0 P1 P2 P3 P4	A B C 0 1 0 2 0 0 3 0 3 2 1 1 0 0 2	A B C 0 0 0 2 0 2 0 0 0 1 0 0 0 0 2	A B C 0 0 0

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>