GATE CSE 2006 | Deadlocks Question 20 | Operating Systems

GATE CSE 2006

MCQ (Single Correct Answer)

-0.6

Consider the following snapshot of a system running n processes. Process i is holding x_i instances of a resource R, for $$1 \le i \le n$$. Currently, all instances of R are occupied. Further, for all i, process i has placed a request for an additional y_i instances while holding the x_i instances it already has. There are exactly two processes p and q such that y_p = y_q = 0. Which one of the following can serve as a necessary condition to guarantee that the system is not approaching a deadlock?

$$\min ({x_p},{x_q}) < {\max _{k \ne p,q}}{y_k}$$

$${x_p} + {x_q} \ge {\min _{k \ne p,q}}{y_k}$$

$$\max ({x_p},{x_q}) > 1$$

$$\min ({x_p},{x_q}) > 1$$

GATE CSE 2005

MCQ (Single Correct Answer)

-0.6

Suppose n processes, P₁,......., P_n share m identical resource units, which can be reserved and released one at a time. The maximum resource requirement of process P_i is S_i, where S_i > 0. Which one of the following is a sufficient condition for ensuring that deadlock does not occur?

$$\forall i,{s_i} < m$$

$$\forall i,{s_i} < n$$

$$\sum\limits_{i = 1}^n {{s_i}} < \left( {m + n} \right)$$

$$\sum\limits_{i = 1}^n {{s_i}} < \left( {m \times n} \right)$$

GATE CSE 2000

MCQ (Single Correct Answer)

-0.6

Which of the following is NOT a valid deadlock prevention scheme?

Release all resources before requesting a new resource

Number the resources uniquely and never request a lower numbered resource than the last one requested.

Never request a resource after releasing any resource

Request and all required resources be allocated before execution.

GATE CSE 1997

MCQ (Single Correct Answer)

-0.6

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