Specifying Distributed Software Architectures：（指定分布式软件体系结构）.pdfVIP

Sp ecifying Distributed Software Architectures Je Magee, Naranker Dulay, Susan Eisenbach and Je Kramer Department of Computing Imp erial College London SW7 2BZ, United Kingdom jnm , nd , se , jk@doc.ic .ac.uk Abstract. There is a real need for clear and sound design sp eci ca- tions of distributed systems at the architectural level. This is the level of the design which deals with the high-level organisation of computa- tional elements and the interactions b etween those elements. The pap er presents the Darwin notation for sp ecifying this high-level organisation . Darwin is in essence a declarative binding language which can b e used to de ne hierarchic comp ositions of interconnected comp onents. Distribu- tion is dealt with orthogonally to system structuring. The language sup- p orts the sp eci cation of b oth static structures and dynamic structures which may evolve during execution. The central abstractions managed by Darwin are comp onents and services. Services are the means by which comp onents interact. In addition to its use in sp ecifying the architecture of a distributed sys- tem, Darwin has an op erational semantics for the elab oration of sp eci - cations such that they may b e used at runtime to direct the construction of the desired system. The pap er describ es the op erational semantics of Darwin in terms of the -calculus, Milners calculus of mobile pro cesses. The corresp ondence b etween the treatment of names in the -calculus and the management of services in Darwin leads to an elegant and con- cise -calculus mo del of Darwins op erational semantics. The mo del