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Deadlock
Definition:
Deadlock in computer science refers to a situation where two or more processes are unable to proceed because each is waiting for the other to release a resource, creating a standstill in the system.
The Concept of Deadlock in Computer Science
Deadlock is a common issue that can arise in computer science, particularly in the field of software development. It occurs when two or more processes are unable to proceed because each is waiting for the other to release a resource.
How does Deadlock happen?
Deadlock occurs in a multithreaded or multitasking environment when the following conditions are met:
1. Mutual Exclusion: At least one resource must be held in a non-sharable mode, meaning only one process can use it at a time.
2. Hold and Wait: A process holding at least one resource is waiting to acquire additional resources held by other processes.
3. No Preemption: Resources cannot be forcibly taken from a process; they must be released voluntarily by the process holding them.
4. Circular Wait: A set of processes each waiting for a resource held by the next process in the set.
Preventing and Resolving Deadlocks
Deadlocks can be prevented by ensuring that at least one of the necessary conditions does not hold. This can be achieved through techniques such as:
1. Lock Ordering: Processes must request resources in a pre-defined order to prevent circular wait.
2. Timeout: Set a limit on how long a process can wait for a resource before releasing its current resources and attempting again later.
3. Resource Allocation Graph: Maintain a graph that tracks resource allocation to detect and prevent circular wait scenarios.
Resolving a deadlock involves breaking the circular wait, either by preempting resources from one or more processes or by killing and restarting processes in the deadlock.
Understanding the concept of deadlock is crucial for software developers as it can impact the performance and reliability of systems. By implementing preventative measures and having strategies in place to resolve deadlocks, developers can ensure the smooth operation of their software applications.
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