Term
| What are the four benefits to multithreaded programming? |
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Definition
Responsiveness
Resource Sharing
Economy
Scalability |
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Term
| What are the two levels that thread support can be provided at? |
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Definition
| User level or kernel level |
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Term
| There are three common ways of establishing the relationship of user threads to kernel threads. What are they? |
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Definition
| Many-To-One model (many users to one kernel)
One-To-One model (each user to a kernel)
Many-to-Many (many user to a smaller or = number of kernel) |
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Term
| What are the issues to consider with multithreaded programming? |
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Definition
Cancellation
The fork() and exec() system calls
Scheduler activations
Signal handling
Thread pools
Thread-specific data |
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Term
| In a single processor system, how many processes can run at a time? |
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Definition
| One, all others must wait until the CPU is free |
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Term
| When does the short-term scheduler select the next process from the ready queue? |
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Definition
| when the CPU becomes idle |
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Term
| CPU scheduling decisions may take place under the following circumstances. What are these circumstances? |
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Definition
| Process switches from the running state to the waiting state
A process switches from the running state to the ready state
A process switches from the waiting state to the ready state
A process terminations |
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Term
| The following Criteria are used for CPU scheduling |
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Definition
CPU utilization
Throughput
Turnaround Time
Waiting Time
Response Time |
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Term
| The following are scheduling algorithms for CPU scheduling |
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Definition
First Come – First Serve
Shortest-Job-First
Priority
Round-Robin
Multi-level queue
Mutli-level feedback queue scheduling |
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Term
| When the OS supports kernel level threads the scheduling is based on what? |
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Definition
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Term
| When scheduling user level threads the _______ scope scheme is used to determine which threads run |
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Definition
| process-contention scope (PCS) |
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Term
| When scheduling kernel level threads the ____ scope scheme is used to determine which thread runs |
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Definition
| System-contention scope(SCS) |
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Term
| The solution to the critical section problem must satisfy the following requirements. |
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Definition
Mutual exclusion
Progress
Bounded waiting |
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Term
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Definition
| When two or more processes/threads are waiting forever for an event that can be caused by only one of the waiting processes/threads |
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Term
| Priority inversion occurs only in what? |
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Definition
| Systems with more than two priorities |
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Term
| The following are classic problems of synchronization. |
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Definition
Bounded-Buffer
Dining-Philosophers |
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Term
| The following four conditions must hold simultaneously in a system for deadlock to occur |
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Definition
Mutual exclustion
Hold and wait
No pre-emption
Circular wait |
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Term
| The following are three general ways we can deal with deadlock |
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Definition
safe state
resource-allocation-graph algorithm
baker’s algorithm |
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Term
| Which of the following is an example where mutual exclusion needs to be applied |
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Definition
| If another process requests a non-sharable resource, the requesting process must be delayed until the resource has been released |
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Term
| Which of the following is an example of hold and wait? |
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Definition
| A process is holding at least one resource and waiting to acquire additional resources that are being held by other processes |
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Term
| What does no preemption mean? |
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Definition
| A resource can only be voluntarily released by the process holding it after that process has completed its task |
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Term
| What does circular wait mean? Given a set of proceses, P0, P1, … Pn |
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Definition
| P0 is waiting for a resource from P1, P1 is waiting for Pn, and Pn is waiting for P0 |
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Term
| Which Deadlock avoidance algorithms can be used to dynamically examine the resource allocations to ensure a circular wait condition does not exist? |
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Definition
| safe state and resource allocation graph |
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Term
| If deadlock prevention and deadlock avoidance are not employed, what other approach can be used? |
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Definition
| Deadlock detection
An algorithm that examines the state of the system to determine whether a deadlock has occurred
An algorithm to recover from the deadlock |
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Term
| If there are several instances of a resource type in the system and you are checking for a deadlock, what other structures do you need? |
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Definition
| A vector of available resources
A matrix that defines the number of resources of each type currently allocated to each process
A matrix that indicates the current request of each process. |
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Term
| What option is a way to recover from a deadlock? |
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Definition
Process termination
Resource preemption |
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