What are some of the practical applications of CSP process algebra? CSP is used for the description and representation of concurrent systems, how it is used in practice (theoretically and programmatically)? 

What are the application areas (other than concurrent and parallel systems) where it is used?
CSP is the formal basis of the programming language Occam which compiled to INMOS Transputers. Transputers appeared in all sorts of devices, such as set-top boxes for satellite TV. Eventually, however, the company doing all of this work failed to achieve commercial success, and was eventually absorbed by another company.