An Implementation Model for Time-Triggered Message-Triggered Object Support Mechanisms in CORBA-Compliant COTS Platforms

Reliable design and implementation of emerging highly complex real-time applications require use of state-of-the-art techniques in systems and software engineering. Object-oriented analysis and design methodologies have become popular in development of non-real-time business data processing applications. However, conventional object-oriented techniques have had minimal impacts on development of real-time applications mainly because these techniques do not explicitly address key characteristics of real-time systems, in particular, timing requirements. The Time-triggered Messagetriggered Object (TMO) structuring is in our view the most natural extension of the object-oriented design and implementation techniques which allow the system designer to explicitly specify timing characteristics of data and function components of an object. To facilitate TMO-based design of real-time systems in the most cost-effective manner, it is essential to provide execution support mechanisms in well-established commercial software/hardware platforms compliant with industry standards. Two recent advances in commercial software that have motivated our development of the TMO support facilities reported here are: (i) recent multi-threaded operating systems and (ii) the CORBA standards for distributed object-oriented systems. In this paper, we present an implementation model for TMO support mechanisms in CORBAcompliant commercial-off-the-self (COTS) platforms. We first introduce a natural and simple mapping between TMO’s and CORBA objects. Then, we identify the services to be provided by the TMO support subsystem and an efficient way these services should be implemented. The rest of the paper discusses the implementation of the proposed model realized on top of the Windows NT operating system and the Orbix object request broker (a commercial implementation of the standard CORBA).