A Theory of As ; ' llshronous Processes

A theory of asynchronous processes (nondeterministic data florv net-rvorks) is presented. It consists of a mathematical model and a process algebra. The intention is to provide a better theoretical underpinning to the Jackson System Development metirod. The model is so constructed as to be compatible rvith the failures modei of Hoare's Communicating Sequential Processes. The process algebra describes the laws that govern a collection of CSP-like operators, convenient for constructing asynchronous process networks from their components. The operators are defined in terms of the model and so their algebraic properties can be verified. As in CSP, the laws are suffi.ciently complete to transform every netrvork r^ r qpnrrpnria.l form This is imnort;r.nt fnr a dpsion rncfhod like JSD, rvhefe the LU 4 JEqUE]LLI@ lVLfrlt rllfr IJ lutl,va resulting programs must be implemented on a traditional sequential computer.