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In computer science, communicating sequential processes (CSP) is a formal language for describing patterns of interaction in concurrent systems. It is a member of the family of mathematical theories of concurrency known as process algebras, or process calculi, based on message passing via channels. CSP was highly influential in the design of the occam programming language,〔〔, INMOS document 72 occ 45 03〕 and also influenced the design of programming languages such as Limbo〔(【引用サイトリンク】url=http://swtch.com/~rsc/thread/ )〕 and Go. CSP was first described in a 1978 paper by Tony Hoare,〔 〕 but has since evolved substantially.〔 〕 CSP has been practically applied in industry as a tool for specifying and verifying the concurrent aspects of a variety of different systems, such as the T9000 Transputer,〔 〕 as well as a secure ecommerce system.〔 〕 The theory of CSP itself is also still the subject of active research, including work to increase its range of practical applicability (e.g., increasing the scale of the systems that can be tractably analyzed).〔 〕 == History == The version of CSP presented in Hoare's original 1978 paper was essentially a concurrent programming language rather than a process calculus. It had a substantially different syntax than later versions of CSP, did not possess mathematically defined semantics, and was unable to represent unbounded nondeterminism. Programs in the original CSP were written as a parallel composition of a fixed number of sequential processes communicating with each other strictly through synchronous message-passing. In contrast to later versions of CSP, each process was assigned an explicit name, and the source or destination of a message was defined by specifying the name of the intended sending or receiving process. For example, the process COPY = *(west?c → east!c ) repeatedly receives a character from the process named west, and then sends that character to process named east. The parallel composition(|| X::COPY || east::ASSEMBLE ) assigns the names west to the DISASSEMBLE process, X to the COPY process, and east to the ASSEMBLE process, and executes these three processes concurrently.〔Following the publication of the original version of CSP, Hoare, Stephen Brookes, and A. W. Roscoe developed and refined the ''theory'' of CSP into its modern, process algebraic form. The approach taken in developing CSP into a process algebra was influenced by Robin Milner's work on the Calculus of Communicating Systems (CCS), and vice versa. The theoretical version of CSP was initially presented in a 1984 article by Brookes, Hoare, and Roscoe, and later in Hoare's book ''Communicating Sequential Processes'',〔 which was published in 1985. In September 2006, that book was still the (third-most cited ) computer science reference of all time according to Citeseer (albeit an unreliable source due to the nature of its sampling). The theory of CSP has undergone a few minor changes since the publication of Hoare's book. Most of these changes were motivated by the advent of automated tools for CSP process analysis and verification. Roscoe's ''The Theory and Practice of Concurrency''〔 describes this newer version of CSP. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「communicating sequential processes」の詳細全文を読む スポンサード リンク
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