THE HELIOS UNIFICATION BUS - A TOOLBOX TO DEVELOP CLIENT SERVER APPLICATIONS/

In the medical domain, new developments commonly rely on client/server architectures. But face to distributed environments, the software dev elopers encounter a tremendously increasing complexity when building i ntegrated applications. This paper presents the HELIOS Unification Bus (HUB), a communication integration framework for the HELIOS medical s oftware engineering environment that allows the err change of data bet ween components that can be hosted on heterogeneous machines linked by a network. The HUB is developed as a C++ toolbox over UNIX and TCP/IP . It includes a message routing entity called router and a generic app lication programming interface (API), implemented as a C++ library, th at allows to build easily software components compliant with the stand ardised HELIOS language. Messages conveyed by the bus are composite ob jects that are serialized to be transmitted over the bus using the ASN .1 ISO presentation protocol. The article describes the use of the bus to ease the development and execution of distributed medical applicat ions and its role from the communication integration standpoint.