A deadlock is a blockage that occurs during transmission in data networks, in the execution of programs and in processor technology. Deadlocks occur when multiple processes are waiting for an event or accessing a resource that can only be used by one process.
In data packet networks, a deadlock occurs when a store-and-forward lockup occurs, which is a partial blocking of the network nodes. Deadlock is also said to occur when two computers attempt to access a resource, with the two systems giving opposite instructions to the resource controller. This then leads to a situation where both systems block each other. The deadlock can be cleared by resetting, powering down, or shutting down the personal computer, with possible loss of data.
It is different with a livelock, where the processes are actively waiting and their states are constantly changing. .