The RAISE specification language a tutorial

Abstract

RAISE Rigorous Approach to Industrial Software Engineering was an ESPRIT project running from 1985 to 1990 and consuming about 120 person years of effort. Dansk Datamatik Center (taken over by Computer Resources International in 1988) were the main contractor. STC Technology (now BNR Europe) were the second partner producing the RAISE technology. Nordisk Brown Boveri (now SYPRO) and part of ICL (now owned by Fujitsu) were involved mainly as industrial trialists. The aim of RAISE was to produce a method for the rigorous development of software, based on a wide spectrum specification language, with accompanying tools and technology transfer material. The main inspiration at the start of the RAISE project was VDM, which was seen as having two major deficiencies. It lacked modularity and it could not deal with concurrency. There was also what was then aeen as a completely different approach, the algebraic. This differed from the model based approach of VDM and Z both in terms of how things were specified but also in how the specification language was given a semantics. It was not at all clear how the two could be combined. Doing so was a major achievement of the RAISE Specification Language RSL. The modularity in RSL is largely inspired by the algebraic languages (CLEAR, ASL, etc.). Concurrency is based on process algebras close to CSP and CCS, but with the interlock operator. And, of course, it was high time there were some decent tools! RSL is a 'wide spectrum' language. This means that it has features allowing its use for very abstract, initial specifications and also for more concrete developments of initial specifications that can be easily (or even automatically) translated into a programming language. We originally wanted a wide spectrum language so that we stayed within one language, and hence within one semantic framework at all development levels. In fact it turns out