#### [[notes_OS_Deadlock]] **Creator**:: [[Nathan Eloe]] **Source**:: [[05_deadlock.pdf]] **Covers**:: Q: What are the four requirements for deadlock A: **Hold and wait** (process holds for more resources), **mutual exclusion** (resource can't be shared), **circular wait** (needs a resource in use), and **no preemption** (resource cannot be taken) which are necessary and sufficient for deadlock Q: How do we avoid deadlock? A: Prevent it, avoid it, detect it, or ignore it, but mutual exclusion and no preemption are preferred practices