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Phantom deadlocks are deadlocks that are falsely detected in a distributed system due to system internal delays but do not actually exist. For example, if a process releases a resource R1 and issues a request for R2 , and the first message is lost or delayed, a coordinator (detector of deadlocks) could falsely conclude a deadlock (if the ...
In computer science, deadlock prevention algorithms are used in concurrent programming when multiple processes must acquire more than one shared resource.If two or more concurrent processes obtain multiple resources indiscriminately, a situation can occur where each process has a resource needed by another process.
A wait-for graph in computer science is a directed graph used for deadlock detection in operating systems and relational database systems.. In computer science, a system that allows concurrent operation of multiple processes and locking of resources and which does not provide mechanisms to avoid or prevent deadlock must support a mechanism to detect deadlocks and an algorithm for recovering ...
Deadlock freedom is a safety property: the "bad thing" is a deadlock (which is discrete). Most of the time, knowing that a program eventually does some "good thing" is not satisfactory; we want to know that the program performs the "good thing" within some number of steps or before some deadline.
Banker's algorithm is a resource allocation and deadlock avoidance algorithm developed by Edsger Dijkstra that tests for safety by simulating the allocation of predetermined maximum possible amounts of all resources, and then makes an "s-state" check to test for possible deadlock conditions for all other pending activities, before deciding whether allocation should be allowed to continue.
However, deadlock-free guarantees cannot always be given, since deadlocks can be caused by callbacks and violation of architectural layering independent of the library itself. Software libraries can provide certain thread-safety guarantees. [5] For example, concurrent reads might be guaranteed to be thread-safe, but concurrent writes might not be.
In computer science, a lock or mutex (from mutual exclusion) is a synchronization primitive that prevents state from being modified or accessed by multiple threads of execution at once. Locks enforce mutual exclusion concurrency control policies, and with a variety of possible methods there exist multiple unique implementations for different ...
Deadlock (computer science), a situation where two processes are each waiting for the other to finish; Political deadlock or gridlock, a situation of difficulty passing laws that satisfy the needs of the people; Negotiation deadlock or an impasse, a situation where two sides bargaining can't reach an agreement; Deadlock or deadlocked may also ...