Numerical Solved by Banker’s Algorithm

Q2. Consider the table given below for a system, find the need matrix and the safety sequence, is the request from process P1(0, 1, 2) can be granted immediately.

Resource – 3 types

A – (10 instances)

B – (5 instances)

C – (7 instances)

Process Allocation Maximum Available Need
P0
P1
P2
P3
P4
A B C
0 1 0
2 0 0
3 0 2
2 1 1
0 0 2
A B C
7 5 3
3 2 2
9 0 2
2 2 2
4 3 3
A B C
3 3 2
     
     
     
     
A B C
7 4 3
1 2 2
6 0 0
0 1 1
4 3 1

Solution: Banker’s Algorithm

Step 1:

Safety for process P0

need0 = (7, 4, 3)

If need0 ≤ Available

if [(7, 4, 3) ≤ (3, 3, 2)] (false)

Process P0 must wait.

Step 2:

Safety for process P0

need1 = (1, 2, 2)

if needi ≤ Available

if [(1, 2, 2) ≤ (3, 3, 2)]

Pi will execute.

Available = Available + Allocation

= (3, 3, 2) + (2, 0, 0)

= (5, 3, 2)

Step 3:

Safety for process P2

need2 = (6, 0, 0)

if need2 ≤ Available

if [(6, 0, 0) ≤(5, 3, 2)] (false)

P3 will execute.

Available = Available + Allocation

= (5, 3, 2) + (2, 1, 1)

= (7, 4, 3)

Step 5:

Safety for process P4

need4 = (4, 3, 1)

If need4 ≤ Available

If [(4, 3, 1) ≤ (6, 4, 3)]

P4 will execute.

Available = Available + Allocation

= (7, 4, 3) + (0, 0, 2)

= (7, 4, 5)

Step 6:

Safety for process P0

                need0 = (7, 4, 3)

if need0 ≤ Available

if [(7, 4, 3) ≤ (7, 4, 5)]

P0 will execute.

Available = Available + Allocation

= (7, 4, 5) + (0, 1, 0)

= (7, 5, 5)

Step 7:

Safety for process P2

need2 = (6, 0, 0)

if need2 ≤ Available

if [(6, 0, 0) ≤ (7, 5, 5)]

P2 will execute.

Available = Available + Allocation

= (7, 5, 5) + (3, 0, 2)

= (10, 5, 7)

 

Safety Sequence = <P1, P3, P4, P0, P2>

3 thoughts on “Numerical Solved by Banker’s Algorithm

  • May 11, 2016 at 6:57 am
    Permalink

    Awesome explaination of banker’s algorithm..!
    Anyone can understand this way..

    Thanx a lot..

    Reply
  • June 4, 2016 at 8:35 pm
    Permalink

    A1 solution thank you sir ………..

    Reply
  • November 16, 2016 at 1:50 pm
    Permalink

    Thanks!!! Very simply and clearly put,

    Reply

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