||Communicating Sequential Processes (CSP) is a well known paradigm for communication and synchronization of a parallel computation. A CSP program consists of a collection of processes P(1), P(2),....., P(N) that interact by exchanging message. These message passing primitives, called input and output commands, are synchronous - a process attempting to output (input) a message to (from) another process must wait until the second process has executed the corresponding input (output) primitive. Most of the algorithms mentioned in the last section assume a message-based computer architecture; no shared memory is assumed. This is natural because CSP does not assume shared memory between constituent processes. One might ask why implementation of CSP on a shared memory machine is an issue. Psychology; Steep deprivation; Cognition.