For sharable resources, mutual exclusion _____ a) is required b) is not required c) may be or may not be required d) none of the mentioned View Answer. In general, however, it is not possible … Resources are allocated to the process on non-sharable basis is (A) mutual exclusion (B) hold and wait (C) no pre-emption (D) circular wait 32. Thread-sharable resources such as Global variables shared by two or more threads. Attempt a small test to analyze your preparation level. These resources are shared by 3 processes A, B, C, which have peak time demands of 3, 4, 6 respectively. 10. A process holds at least one resource and requests another resource that is held by another process. The solution appears to do everything right: All accesses to the shared variables are protected by mutual exclusion, processes do not block themselves while in the mutual exclusion, new processes are prevented from using the resource if there are (or were) three active users, and the last process to depart unblocks up to three waiting processes. Read-only files are a good example of a sharable resource. processes that have previously been in the system, resources currently allocated to each process, future requests and releases of each process. A directory of Objective Type Questions covering all the Computer Science subjects. Here you can access and discuss Multiple choice questions and answers for various compitative exams and interviews. For sharable resources, mutual exclusion : A. is required B. is not required C. None of these 18. Mutual Exclusion. For example, a Printer is a non-sharable resource. Mutual Exclusion. Mutual exclusion - The resources involved must be unshareable; otherwise, the processes would not be prevented from using the resource when necessary. For example, only one process can have access to a printer at a time, otherwise the output gets garbled up. The disadvantage of a process being allocated all its resources before beginning its execution is : To ensure no preemption, if a process is holding some resources and requests another resource that cannot be immediately allocated to it : then the process waits for the resources be allocated to it, the process keeps sending requests until the resource is allocated to it, the process resumes execution without the resource being allocated to it, then all resources currently being held are preempted. advertisement. none of the mentioned. 3. This GATE exam includes questions from previous year GATE papers. That is, several processes cannot simultaneously share a single resource. 31. Some resources can be made sharable, like a read-only file. What is the maximum value of 'n' for the system to be deadlock free? The mutual exclusion condition must hold for non-sharable types of resources. Questions from Previous year GATE question papers, UGC NET Previous year questions and practice sets. Sharable resources, in contrast, do not require mutually exclusive access and thus cannot be involved in a deadlock. Mutual Exclusion. 2. hold and wait: there must be a process holding one resource and waiting for another. Questions from Previous year GATE question papers, UGC NET Previous year questions and practice sets. Resources that a process holds, can only be voluntarily released by the process itself. The number of resources requested by a process : Deadlock prevention is a set of methods : Every time a request for allocation cannot be granted immediately, the detection algorithm is invoked. Mutual exclusion - The resources involved must be unshareable; otherwise, the processes would not be prevented from using the resource when necessary. If several processes attempt to open a read only file at the same time, they can be granted simultaneous access to the file. several processes cannot simultaneously share a single resource. That is, several processes cannot simultaneously share a single resource. Each request requires that the system consider the _____________ to decide whether the current request can be satisfied or must wait to avoid a future possible deadlock. 4. In this situation, mutual exclusion cannot be prevented. Answer. ……………. improves the performance This condition is difficult to eliminate because some resources, such as the tap drive and printer, are inherently non-shareable. is not required. Circular wait. Here you can access and discuss Multiple choice questions and answers for various compitative exams and interviews. Mutual exclusion condition must hold for non-sharable resources. A process never needs to wait for a sharable resource. Question. Practice test for UGC NET Computer Science Paper. This will help identify : A system has 3 processes sharing 4 resources. It means only one process at a time can use a resource. Hold and wait or partial allocation - The processes must hold the resources they have already been allocated while waiting for other (requested) resources. Operating System Concepts –9th Edition 7.6 Silberschatz, Galvin and Gagne ©2013 Deadlock Characterization Mutual exclusion: only one process at a time can use a resource Hold and wait: a process holding at least one resource is waiting to acquire additional resources held by other processes No preemption: a resource can be released only voluntarily Deadlock prevention is a set of methods : to ensure that at least one of the necessary conditions cannot hold, to ensure that all of the necessary conditions do not hold, to decide if the requested resources for a process have to be given or not. If we have non-sharable resources that cannot be shared, then, in that case, we cannot prevent mutual exclusion from happening. This condition is difficult to eliminate because some resources, such as the tape drive and printer, are inherently non-shareable.check this. 2. No preemption: resources cannot be preempted. For a Hold and wait condition to prevail : A process must be not be holding a resource, but waiting for one to be freed, and then request to acquire it, A process must be holding at least one resource and waiting to acquire additional resources that are being held by other processes, A process must hold at least one resource and not be waiting to acquire additional resources. For example, a printer cannot be simultaneously shared by several processes. Mutual exclusion is one of the conditions for a deadlock to occur. For example, If process P1 requests the resource R1 then process P2 must wait til resource R1 has been released by process P1. No preemption. Answer: b Explanation: They do not require mutually exclusive access, and hence cannot be involved in a deadlock. Which memory models are best suited (i.e. Cost factors of process termination include . 4. circular wait: there must exist a set of processes [p1, p2, …, pn] such that p1 is waiting for p2, p2 for p3, and so on…. 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