Communicating Sequential Processes Specifications Research Articles

FDR Explorer

Abstract We describe: (1) the internal structures of FDR, the refinement model checker for Hoare’s Communicating Sequential Processes (CSP); and (2) an application-programming interface (API) that allows users to interact more closely with FDR and to have finer-grain control over its behaviour and data structures. This API makes it possible to create optimised CSP code to perform refinement checks that are more space or time efficient, enabling the analysis of more complex and data-intensive specifications. The API can be used either by those constructing CSP models or by tools that automatically generate CSP code. We present examples of using our tool, including handling advanced FDR features such as transparent functions, which compress state spaces before checking. We also show how to transform FDR’s graph format into a graph notation such as JGraph, enabling visualisation of labelled transition systems of CSP specifications.

FDR Explorer

In this paper we describe the internal structures of FDR, the refinement model checker for Hoare's Communicating Sequential Processes (CSP), as well as an Application Programming Interface (API) allowing one to interact more closely with, and have fine grained control over, FDR's behaviour and data structures. With such information it is possible to create optimised CSP code to perform refinement checks that are more space/time efficient, hence enabling the analysis of more complex and data intensive specifications. This information is very valuable for both CSP users and tools that automatically generate CSP code, such as those related to security analysis generating test-cases as CSP processes. We also present a simple example of using the tool. Finally, we show how one can transform FDR's graph format into a graph notation (e.g., JGraph), hence enabling visualisation of Labelled Transition Systems (LTS) of CSP specifications.

Converging CSP specifications and C++ programming via selective formalism

CSP (communicating sequential processes) is a useful algebraic notation for creating a hierarchical behavioral specification for concurrent systems, due to its formal interprocess synchronization and communication semantics. CSP specifications are amenable to simulation and formal verification by model-checking tools. A translator has been created to synthesize C++ code from CSP for execution with an object-oriented framework called CSP++, thereby making CSP specifications directly executable. To overcome the drawback that CSP is neither a full-featured nor popular programming language, an approach called “selective formalism” allows the use of CSP to be limited to specifying the control portion of a system, while the rest of its functionality is supplied in the form of C++ modules. These are activated through association with abstract events in the CSP specification. This is a new means of bringing convergence between a formal method and a popular programming language. It is believed that this methodology can be extended to hardware/software codesign for embedded systems.