Jrec is the music database/server. It maintains a searchable database of all the music it scans. It also streams the music to clients such as WinAmp and tRio.

tRio is the server for the RIO. The RIO device actually has no operating system on it. When it starts up it broadcasts to the network looking for a server that can provide its operating system. When it finds one, it boots the operating system from it. The tRio server provides an alternate client implementation to the one that ships with the RIO.

You configure tRio to tell it where the music server (Jrec)is. When it connects to the music server, the music server can stream the music to the tRio server which in turn streams it to the RIO.

HTH,
Bill