Designing distributed software with RT-CORBA and SDL

The use of formal description techniques (FDTs), and specifically SDL, has emerged as an interesting way of designing embedded real time distributed systems (ERTDSs) taking into account the increasing complexity of this kind of system. The communication platform for these ERTDSs should be included at the design stage in order to consider the behaviour of the communications. RT-CORBA is an interesting alternative as a middleware for real-time distributed applications because, unlike standard CORBA, it guarantees predictable temporal response to invocations to remote objects. We propose a set of design patterns in SDL for the RT-CORBA middleware so that users can integrate the communication behavior into their designs. This approach provides three important results: firstly, it is possible to carry out the simulation and validation of the whole system including communications; secondly, the implementation stage is simplified because the integration of RT-CORBA allows code to be generated from the design. Finally, different analysis techniques at design level for ERTDS including the temporal behavior of RT-CORBA middleware can be carried out. To apply our proposals we have integrated the design of RT-CORBA with the SDL specification of a distributed control application called Siroco.