Experimental Physics and
Industrial Control System

    It's not quite same. . .   For a customer I recently implemented EPICS for their system, running the Timesys Embedded Linux kernel.  The overall system has 2 (main) components:  The EPICS and a "high speed" data streaming server, connected via a TCP/IP Socket connection to a client.  When the Server gets connected, it provides an indication to EPICS that it's connected by creating a file in the Linux RFS.  In the EPICS code, this file gets polled via Record definition (SCAN), that then reports the status to the EPICS Client.  So in the ASYN processing, I call a "backend" function that checks if this file exists (using std Linux API's) and return either a 1 or 0 (exists or not).  This is what then gets returned back through the EPICS database.