What does 'deadlock' refer to in computer science?

In computer science, 'deadlock' specifically refers to a scenario where two or more processes cannot proceed because each is waiting for a resource that the other process holds. This mutual waiting creates a cycle of dependency where none of the processes can continue execution, leading to a complete halt in progress.

Deadlocks often occur in systems that manage multiple resources among competing processes, and recognizing this condition is fundamental for designing robust operating systems. In practice, deadlocks can cause significant issues in system performance, as processes become stuck indefinitely without a means to recover unless specific deadlock detection or avoidance strategies are employed.

This concept is distinct from the other options, which may touch on related themes but do not encapsulate the essence of what deadlock truly represents. For example, while waiting for an unavailable resource is part of the broader context of resource management, it doesn't highlight the interdependency characteristic central to a deadlock situation.