Concurrent Access to Remote Instrumentation in CORBA–Based Distributed Environment

Abstract

This paper describes a system architecture for a distributed measurement process. Base systems provide only low-level bus oriented communication protocol (realized with General Purpose Interface Bus hardware and software). Distribution and remote control [1][2] requirements led to the design of CORBA [3][4] (Common Object Request Broker Architecture) middleware objects [5][6] that abstract underlying hardware/software installation issues. This design addresses problems of authentication, authorization, provision of exclusive instrument access from one client by enabling instrument locking mechanism, and session oriented communication due to CORBA’s inability to provide satisfactory solutions to these matters. The central point of the design is the introduction of a special GPIB arbiter object. An arbiter object represents implementation of the factory pattern providing access to instrument objects for each client connecting to the arbiter. In order to secure uniqueness of connection session and allow authorization and authentication of remote clients, session oriented connection has been introduced. It was found as necessity to describe proposed solution in the form of a software design pattern[7][9].