Specifying distributed system services

Building a software service requires careful analysis of the requirements given by the customer for the system. It is often difficult to understand the system requirements correctly, due to the fact that they are usually described in plain language. This difficulty could be overcome if a sufficiently precise description of system services to be provided can be produced that is easy to follow by both customers and designers. Given such a specification of a service that on the surface permits several ways of implementing it, the design team should be able to select with reasonable confidence, the most appropriate set of design options, before commencing the building of the service. Naturally, this requires the development of modelling and analysis techniques that enable the evaluation of various design options for a given service. As a first step towards achieving these goals, the paper briefly reviews current approaches to specifying system architectures and explores the suitability of the Unified Modelling Language (UML) as a specification tool.