A DIM based communication protocol to build generic control clients

Control systems commonly use servers publishing data or actions, and clients like graphical user interfaces (GUI) subscribing for data. Clients get the data synchronously or asynchronously and can launch actions at the server. Examples are EPICS or DIM based systems. If the setup of servers is stable one can design optimized GUIs for these setups. If, however, very different setups have to be controlled by one GUI, or the setups change rapidly like in a development phase, a generic approach is very convenient. A generic GUI should subscribe to all published parameters and present them nicely. It should offer all commands together with their argument definitions. Such a generic approach has been implemented on top of the DIM services.