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What is a homonym for weight?
Wait
Is wait up a verb?
The term 'wait up' is a verb (wait) and adverb(up) combination.
What adverb goes with wait?
Patiently is an adverb that would go with wait.
What is another word for unable to wait?
Other words to describe "unable to wait" would be impatient, eager or anxious.
What is another homophone for weight?
wait
What is the difference between resource allocation graph and wait for graph?
In Wait for Graph the request edge is a directed edge Pi → Pj which indicates that process Pj is holding a resource that process Pi needs and thus Pi is waiting for Pj to release its lock on that resource. It does not have any allocation edge.In case of Resource Allocation Graph the request edge is a directed edge Pi → Rj which indicates that process Pi is requesting resource Rj. It has an allocation edge from Rj→Pk when the resource Rj is allocated to process Pk.The way the graphs are drawn are also different but both of them are used in deadlock detection.
What is the use of resource allocation and wait for graph and difference between both?
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How can a deadlocks be avoided?
Deadlocks can be avoided through several strategies, such as resource ordering, where resources are assigned a strict order and processes must request them in that order. Another approach is to use a timeout mechanism, allowing processes to release resources if they cannot acquire all they need within a specified timeframe. Additionally, implementing a wait-die or wound-wait scheme can help manage resource allocation by prioritizing processes based on their age or importance, thus preventing circular wait conditions. Finally, ensuring that processes hold resources for the minimum time necessary can also reduce the likelihood of deadlocks.
What is transaction wait for graph (TWF)?
A Transaction Wait-For Graph (TWF) is a directed graph used in database systems to represent the wait-for relationships among transactions. In this graph, each node represents a transaction, and a directed edge from transaction A to transaction B indicates that transaction A is waiting for a resource held by transaction B. By analyzing the TWF, database systems can detect deadlocks; if there is a cycle in the graph, it indicates that a deadlock has occurred, prompting the system to take corrective action. This method is crucial for maintaining concurrency and ensuring efficient transaction management.
What are the deadlock detection algorithms?
Deadlock is a scenario where two or more processes are blocked, each waiting for the other to release the necessary resources to complete their execution. This situation can cause the entire system to become unresponsive, leading to reduced performance and potentially crashing the system. To avoid this, it is essential to have an effective deadlock detection algorithm in place. Several deadlock detection algorithms are used in modern computer systems. These algorithms use different approaches to detect deadlocks, and each algorithm has its strengths and weaknesses. Wait-for Graph Algorithm: The wait-for graph algorithm is a commonly used deadlock detection algorithm. In this algorithm, a directed graph is created, where the nodes represent the processes, and the edges represent the resources they are waiting for. The algorithm checks if there is a cycle in the graph. If there is a cycle, there is a deadlock in the system. The wait-for-graph algorithm has a few limitations. It can only detect deadlocks and does not provide any mechanism to recover from them. Also, the algorithm may only work well in large systems with a few resources. Resource Allocation Graph Algorithm: The resource allocation graph algorithm is another widely used deadlock detection algorithm. This algorithm creates a graph where the nodes represent the processes and the resources they hold or need. The algorithm checks for cycles in the graph. If there is a cycle, there is a deadlock in the system. The resource allocation graph algorithm is easy to implement and provides an efficient way to detect deadlocks. However, the algorithm requires considerable memory to store the graph, and it can be slow in large systems. Banker's Algorithm: The Banker's algorithm is a resource allocation and deadlock avoidance algorithm. In this algorithm, each process is given a maximum limit on the number of resources it can use. The algorithm checks if granting the requested resources will result in a safe state or not. If the state is safe, the resources are allocated to the process. If the condition is unsafe, the process is put on hold. The Banker's algorithm is an efficient way to prevent deadlocks. However, it requires considerable overhead to maintain the system's state, and it may only work well in systems with a few resources. Ostrich Algorithm: The Ostrich algorithm is a dynamic deadlock detection algorithm. This algorithm assumes a process is deadlocked if it does not progress for a specified period. The algorithm periodically checks the progress of each method and detects if any process is deadlocked. The Ostrich algorithm is efficient in detecting deadlocks in dynamic systems. However, it may not work well in systems where the processes are short-lived, and the algorithm may not detect deadlocks that occur over a short period. Timeout-based Algorithm: The timeout-based algorithm is another dynamic deadlock detection algorithm. This algorithm sets a timer for each resource request made by a process. If the requested resource is not allocated within the specified time, the process is assumed to be deadlocked. The timeout-based algorithm is an efficient way to detect deadlocks in dynamic systems. However, the algorithm may not work well in systems where the processes are short-lived, and it may produce false positives if the time-out period is too short.
When does a dead lock occur?
• Deadlocks can occur in any concurrent system where processes wait for each other and a cyclic chain can arise with each process waiting for the next one in the chain. • More specifically, deadlocks can occur in any system that satisfies the four Coffman conditions (due to E. G. Coffman in 1971): 1. Mutual Exclusion Condition: a resource is either assigned to one process or it is available 2. Hold and Wait Condition: processes already holding resources may request new resources 3. No Preemption Condition: only a process holding a resource may release it 4. Circular Wait Condition: two or more processes form a circular chain where each process requests a resource that the next process in the chain holds • Concurrent Java programs may satisfy these conditions, with the object locks/monitors as the resources, so they may deadlock. • We can avoid deadlocks by arranging our program so that one of the Coffman conditions doesn't hold.
Resource-Request Algorithm for Process?
Let Request i be the request vector for process Pi. If Request [i, j] = k, then process Pi wants k instances of resource type Rj. When a request for resources is made by process Pi, the following actions are taken: 1. If Request i < Need i, go to step 2. Otherwise, raise an error condition, since the process has exceeded its maximum claim. 2. If Request i  Available, go to step 3. Otherwise, Pi must wait, since the resources are not available. 3. Have the system pretend to have allocated the requested resources to process Pj by modifying the state as follows: Available: = Available – Request i; Allocation i := Allocation + Request i; Need i := Need i – Request i; If the resulting Resource-allocation State is safe, the transaction is completed and process Pi is allocated its resources. However, if the new state is unsafe, then Pi must wait for Request i and the old resource-allocation state is restored.
How can the circular wait condition be prevented?
Circular wait prevention consists of allowing processes to wait for resources, but ensure that the waiting can't be circular. One approach might be to assign a precedence to each resource and force processes to allocate resources in order of increasing precedence. That is to say that if a process holds some resources, and the highest precedence of these resources is m, then this process cannot request any resource with precedence smaller than m. This forces resource allocation to follow a particular and non-circular ordering, so circular wait cannot occur.
Can deadlock be resolved without selecting a victim?
Yes, deadlock can be resolved by avoiding the conditions that lead to it, breaking the circular wait, or using deadlock prevention techniques like resource allocation graph, timeouts, or priority-based techniques. In some cases, deadlock can also be prevented by ensuring a single thread holds all resources simultaneously or by using a deadlock detection algorithm to preemptively handle it.
Show how deadlocks may be modeled using Petri Nets?
Deadlocks can be modeled using Petri Nets by representing processes as places and resources as transitions. In this model, tokens in the places signify the availability of resources or the state of processes. A deadlock occurs when there is a circular wait condition, where each process holds a resource that the next process in the cycle needs, leading to a situation where no process can proceed. The Petri Net structure can visually illustrate these interactions and the states leading to deadlock, allowing for analysis and identification of potential deadlock situations.
How deadlock can be prevented?
Deadlock can be prevented by using techniques such as enforcing a strict ordering of resource requests, implementing a timeout mechanism that releases resources if they are not available within a certain time frame, using resource preemption to forcibly take resources from one process to allocate to another, or designing systems that minimize the possibility of circular wait conditions. Additionally, avoiding the use of multiple resources at the same time or reducing resource contention can also help prevent deadlock.
What is hold and wait condition?
A process or thread holding a resource while waiting to get hold of another resource
