Data Distribution Service as an Alternative to CORBA Notify Service of the ALMA Common Software
G.Chiozzi, G.Chiozzi*, H.Sommer (ESO) , J. A. Avarias
The ALMA Common Software (ACS) provides the infrastructure for the Atacama Large Millimeter Array and other projects. ACS, based on CORBA, offers basic services and common design patterns. One of these services is the Notification Channel. Based on the CORBA Notify Service, it allows the implementation of applications based on the publisher-subscriber pattern. This is very useful for handling asynchronous messages between components, and fosters data-centric architectures and de-coupling between different components of an application. The Notify Service has several limitations, such as being resource intensive and not scaling well with the number of subscribers. The Data Distribution Service (DDS) provides an alternative standard for publisher-subscriber communication for real-time systems, offering better performance and featuring decentralized message processing, scalable peer-to-peer communication, and a wide set of QoS policies. We describe the integration of DDS into the ACS CORBA environment, replacing the Notify Service. Benefits and drawbacks are analyzed. A benchmark is presented, comparing the performance of both implementations.