Real-time Concepts for a Formal Specification Language for Software Hardware Systems

Increasingly complex systems are being designed that consist of concurrently operating and communicating processes, often combining both hardware and software. A methodology for high level specification and design of software/ hardware systems (SHE [1]) has been designed to cope with this increasing complexity. SHE incorporates a formal specification language named POOSL. Many systems today can be characterised as real-time. The timing properties of such a real-time system determine the correctness of an implementation. This paper describes the extension of the language POOSL with a notion of time and with real-time primitives, which enable it to specify and model timing properties. Concepts and aspects related to timing and concurrency are discussed and options for introducing time and adding temporal meaning to existing elements of the language are investigated. The language POOSL and its formal semantics have been extended with a notion of time and a new primitive has been added. It..