Designing systems to avoid deadlock conditions
Deadlock prevention involves designing a system in such a way that at least one of the four necessary conditions for deadlock cannot hold. This approach ensures that deadlocks are impossible by system design. The strategies include: 1) Preventing Mutual Exclusion - Make all resources sharable (not always possible, e.g., printers cannot be truly shared). 2) Preventing Hold and Wait - Require processes to request all resources before execution or release all resources before requesting new ones. 3) Preventing No Preemption - Allow the system to forcibly take resources from processes (complicated and may cause issues). 4) Preventing Circular Wait - Impose a total ordering of resource types and require processes to request resources in increasing order. Each prevention strategy has trade-offs: preventing mutual exclusion is often impractical for physical devices; preventing hold and wait can lead to poor resource utilization; preemption may be difficult to implement safely; and enforcing resource ordering adds complexity. Deadlock prevention is often used in real-time and embedded systems where predictability is more important than optimal resource utilization. The choice of prevention strategy depends on system requirements, resource types, and performance considerations.