Locally Distributed Predicates: A Technique for Distributed Programming

New research in wireless networks, sensor networks, and modular robotics has spurred renewed interest in distributed programming techniques. Distributed programming is inherently more difficult than its single-threaded equivalent, due to the need for an executing thread of a distributed program located at one computation node to access state located at a different node. Traditionally, remote state has been aggregated or summarized using distributed snapshots or global predicate evaluation. Traditional techniques for gathering state in distributed systems may be inappropriate for large-scale, sparsely-connected systems, as they are bandwidth intensive and scale poorly. The authors have identified a novel class of distributed predicates in such systems that they term Locally Distributed Predicates (LDPs).