Data Structures for the Banker’s Algorithm

Let n = number of processes, and m = number of resources types. 

• Available:  Vector of length m. If available [j] = k, there are k instances of resource type Rj available.
• Max: n x m matrix.  If Max [i,j] = k, then process Pi may request at most k instances of resource type Rj.
• Allocation:  n x m matrix.  If Allocation[i,j] = k then Pi is currently allocated k instances of Rj. 
• Need:  n x m matrix. If Need[i,j] = k, then Pi may need k more instances of Rj to complete its task.

Need [i,j] = Max[i,j] – Allocation [i,j].