Operating System
Q71.
Consider a system with 4 types of resources R1 (3 units), R2 (2 units), R3 (3 units), R4 (2 units). A non-preemptive resource allocation policy is used. At any given instance, a request is not entertained if it cannot be completely satisfied. Three processes P1, P2, P3 request the sources as follows if executed independently. Which one of the following statements is TRUE if all three processes run concurrently starting at time t=0?Q72.
Consider a system having 'm' resources of the same type. The resources are shared by 3 processes A, B, C, which have peak time demands of 3, 4, 6 respectively. The minimum value of 'm' that ensures that deadlock will never occur isQ74.
Consider the following snapshot of a system running n processes. Process i is holding x_{i} instances of a resource R, for 1\leq i\leq 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?Q75.
Two shared resources R_1 and R_2 are used by processes P_1 and P_2. 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_k from process P_j if T_{ik} is greater than T_{jk}. Given the following : (I). T_{11} \gt T_{21} (II). T_{12} \gt T_{22} (III). T_{11} \lt T_{21} (IV). T_{12} \lt T_{22} Which of the following conditions ensures that P_1 and P_2 can never deadlock?Q76.
In which of the following four necessary conditions for deadlock processes claim exclusive control of the resources they require?Q77.
When a process is rolled back as a result of deadlock the difficulty which arises isQ78.
The following are the starting and ending times of activities A,B,C,D,E,F,G and H respectively in chronological order: a_{s}\; b_{s} \; c_{s}\;a_{e}\;d_{s}\;c_{e}\;e_{s}\;f_{s}\;b_{e}\;d_{e}\;g_{s}\;e_{e}\;f_{e}\;h_{s}\;g_{e}\;h_{e} . Here, x_{s} denotes the starting time and x_{e} denotes the ending time of activity X. W need to schedule the activities in a set of rooms available to us. An activity can be scheduled in a room only if the room is reserved for the activity for its entire duration. What is the minimum number of rooms required?Q80.
In a certain operating system, deadlock prevention is attemped using the following scheme. Each process is assigned a unique timestamp, and is restarted with the same timestamp if killed. Let P_h be the process holding a resource R, P_r be a process requesting for the same resource R, and T(P_h) and T(P_r) be their timestamps respectively. The decision to wait or preempt one of the processes is based on the following algorithm. if T(Pr) < T(Ph) then kill Pr else wait Which one of the following is TRUE?