Q61,paper3, j13. An operating system using banker’s algorithm for deadlock avoidance has ten dedicated devices (of same type) and has three processes P1, P2 and P3 with maximum resource requirements of 4, 5 and 8 respectively. There are two states of allocation of devices as follows :

State 1

Processes	P1	P2	P3
Devices allocated	2	3	4

State 2

Processes		P1	P2	P3
Devices	allocated	0	2	4

Which of the following is correct ?

(A) State 1 is unsafe and state 2 is safe.

(B) State 1 is safe and state 2 is unsafe.

(C) Both, state 1 and state 2 are safe.

(D) Both, state 1 and state 2 are unsafe.

Answer B.

Explanation.

State 1

Processes	P1	P2	P3
Devices allocated	2	3	4
Max Demand	4	5	8
Demand-Alloction	2	2	4

State 1 is safe  total demand-allocation is less than 10.(available)

State 2

Processes Devices allocated	P1	P2	P3
	0	2	4
Max Demand	4	5	8
Demand-Alloction	4	3	4

State 2  is unsafe because demand-allocation is > 10(availability).