Kahn Process Networks

In 1974, Gilles Kahn wrote a short paper [44] describing a simple language for parallel processing that provides a theoretical basis for dataflow computation. A system in Kahn’s language is a set of sequential processes running concurrently that communicate through single-sender, single-receiver fifo queues. A process that tries to read from an empty queue waits until data is available and cannot ask whether data is available before reading. Kahn showed these restrictions make these systems deterministic, that is, the sequence of messages that pass through each queue does not depend on the speed of the processes or the order in which they execute.