Object request brokers (ORBs) are an enriched middleware platform — compared with their predecessors, RPC middleware — including program activation, which most RPCs did not offer. Full-featured CORBA ORBs are transactional platforms, with a special affinity for the object-oriented programming model, including the activation and communications services that are particularly geared to the object-oriented software model. ORB vendors added transaction management, security and other features to their ORBs to enable demanding production applications. OMG CORBA emerged as the widely shared standard programming model for ORBs.