Distributed System

A system consisting of multiple processing nodes (which, depending on the scale being considered, can be different processes running on a single CPU, individual CPUs in a MultiProcessor? system; individual computers on a network, a cluster/server farm, or even an entire "site" on a WideAreaNetwork?), which work together to solve some problem or benefit some enterprise, and for which communication between nodes is either expensive (in terms of bandwidth or latency, not $$$), unreliable, or both. In many cases, the configuration of the network may dynamically change, often without warning or any centralized control.

Writing software for DistributedSystems is a long-standing problem in ComputerScience.

Just some problems that occur in DistributedSystems:

• Discovering the topology of the "network", and/or changes to the topology.
• Determining if a particular link or node has failed, or is providing low QualityOfService?
• Low-level references/poitners valid on one node may not be valid on another
• Determining if messages sent from one node to another arrive a) at all, b) completely, c) in the correct order, and d) without errors.
• Naming things in a DistributedSystem
• DistributedGarbageCollection (and more generally, distributed resource management)
• All problems related to synchronization and concurrency, but worse (avoidance of DeadLock, RaceConditions, data integrity, etc.)