Ralph,
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.
I also read setup files @ initialization time from SD Card (Root File System is RAM based), some of which is fixed data, other which is parameter data. However, this is a "one time" read in the INIT code for EPICS when it boots.
I don't know about StreamDevice support, but I supposed it's possible do do what you want. . . .
