Deadlock

Question 41

An operating system contains 3 user processes each requiring 2 units of resource R. The minimum number of units of R such that no deadlocks will ever arise is

• 3
• 5
• 4
• 6

Question 42

Two shared resources R₁ and R₂ are used by processes P₁ and P₂. Each process has a certain priority for accessing each resource. Let T_ij denote the priority of P_i for accessing  R_j. A process P_i can snatch a resource R_h from process P_j if T_ik is greater than T_jk. Given the following :

1. T₁₁ > T₂₁
2. T₁₂ > T₂₂
3. T₁₁ < T₂₁
4. T₁₂ < T₂₂

Which of the following conditions ensures that P₁ and P₂ can never deadlock?  

• (I) and (IV)
• (II) and (III)
• (I) and (II)
• None of the above