Test
os 8
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Preguntas del test (15)
1A deadlocked state occurs whenever ____.
- Aa process is waiting for I/O to a device that does not exist
- Bthe system has no available free resources
- Cevery process in a set is waiting for an event that can only be caused by another process in the set
- Da process is unable to release its request for a resource after use
2One necessary condition for deadlock is ____, which states that at least one resource must be held in a nonsharable mode.
- Ahold and wait
- Bmutual exclusion
- Ccircular wait
- Dno preemption
3One necessary condition for deadlock is ______, which states that a process must be holding one resource and waiting to acquire additional resources.
- Ahold and wait
- Bmutual exclusion
- Ccircular wait
- Dno preemption
4One necessary condition for deadlock is ______, which states that a resource can be released only voluntarily by the process holding the resource.
- Ahold and wait
- Bmutual exclusion
- Ccircular wait
- Dno preemption
5One necessary condition for deadlock is ______, which states that there is a chain of waiting processes whereby P0 is waiting for a resource held by P1, P1 is waiting for a resource held by P2, and Pn is waiting for a resource held by P0.
- Ahold and wait
- Bmutual exclusion
- Ccircular wait
- Dno preemption
6The witness software product is a ____.
- Alock-order verifier that uses mutual-exclusion locks to protect critical sections
- Bmodeler to develop resource allocation graphs
- Cdriver that can be used to prevent mutual exclusion for nonsharable resources
- Dimplementation of the banker's algorithm available for most operating systems
7In a system resource-allocation graph, ____.
- Aa directed edge from a process to a resource is called an assignment edge
- Ba directed edge from a resource to a process is called a request edge
- Ca directed edge from a process to a resource is called a request edge
- DNone of the above
8A cycle in a resource-allocation graph is ____.
- Aa necessary and sufficient condition for deadlock in the case that each resource has more than one instance
- Ba necessary and sufficient condition for a deadlock in the case that each resource has exactly one instance
- Ca sufficient condition for a deadlock in the case that each resource has more than once instance
- Dis neither necessary nor sufficient for indicating deadlock in the case that each resource has exactly one instance
9To handle deadlocks, operating systems most often _____.
- Apretend that deadlocks never occur
- Buse protocols to prevent or avoid deadlocks
- Cdetect and recover from deadlocks
- DNone of the above
10Which of the following statements is true?
- AA safe state is a deadlocked state.
- BA safe state may lead to a deadlocked state.
- CAn unsafe state is necessarily, and by definition, always a deadlocked state.
- DAn unsafe state may lead to a deadlocked state.
11Suppose that there are ten resources available to three processes. At time 0, the following data is collected. The table indicates the process, the maximum number of resources needed by the process, and the number of resources currently owned by each process. Which of the following correctly characterizes this state?
Process Maximum Needs Currently Owned P0 10 4 P1 3 1 P2 6 4- AIt is safe.
- BIt is not safe.
- CThe state cannot be determined.
- DIt is an impossible state.
12Suppose that there are 12 resources available to three processes. At time 0, the following data is collected. The table indicates the process, the maximum number of resources needed by the process, and the number of resources currently owned by each process. Which of the following correctly characterizes this state?
Process Maximum Needs Currently Owned P0 10 4 P1 3 2 P2 7 4- AIt is safe.
- BIt is not safe.
- CThe state cannot be determined.
- DIt is an impossible state.
13Which of the following data structures in the banker's algorithm is a vector of length m, where m is the number of resource types?
- ANeed
- BAllocation
- CMax
- DAvailable
14Assume there are three resources, R1, R2, and R3, that are each assigned unique integer values 15, 10, and 25, respectively. What is a resource ordering which prevents a circular wait?
- AR1, R2, R3
- BR3, R2, R1
- CR3, R1, R2
- DR2, R1, R3
15A _____ could be preempted from a process.
- Amutex lock
- BCPU
- Csemaphore
- Dfile lock
Información
- Descripción
- Test sobre os 8, creado por Adam Whiteside el 24/04/2019.
- Autor
- Adam Whiteside
- Idioma
- English
- Visitas
- 47
- Valoración
- Aún sin valoraciones Valora este test