I just listened to John Darko’s review of the Wyred 4 Sound music server. I always enjoy his reviews but am often lost with terminology, often basic terminology. He mentions the Wyred server can be a streamer/server also, as the roon core can be physically on the device, and then serve to itself (or something?).
Is the roon nucleus ( which I have ) also a server/streamer in that sense?
What is the simple definition of a streamer vs server?
Thanks
No idea really how the hifi crowd defines it officially - if at all - but I would put it like this:
A server is capable of storing audio files in various formats like .aac, .alac, .flac, .wav and .mp3 and others and presenting those files to connected - usually networked - devices. It serves the files to devices which then must be able to read them.
A streamer now reads those audio files and “unpacks” 'em to something a DAC can make use of like PCM or DSD. But it can’t hold / store the files.
What you encounter often nowadays are Streaming DACs - which can read / “unpack” audio files and do the D-to-A conversion in one device.
A Roon core could be seen as a self serving gated streamer. In it’s ROCK / Nucleus incarnation it would also be a file server. And if you want: a DAC too.
A really clear explanation. Thankyou.
In Roons case the Roon core does all the unpacking so the streamer only receives pcm.
I had some trouble applying my definitions to a Roon core. 
Because somehow it’s neither a server nor a streamer - and somehow it is. So I did invent “self serving gated streamer” … self serving and gated because all devices wanting to receive audio from a Roon core controlled music library need to speak RAAT (or another proprietary protocol Roon supports) to get audio served - and strictly speaking it’s not unpacked PCM / DSD since it’s RAAT enclosed.
You’ve gone pedantic to the point of making your statement useless. By your definition, there can be no unpacked PCM/DSD at all, since it is always encapsulated.
Even SPDIF has Biphase Mark Code, and a dumb TCP pipe contains TCP framing, IP framing, and Ethernet framing.
This is an excellent description. The only words I would change are: “storing” -> “managing” and “those files” -> “the audio data”. Then it’d cover UPnP, iOS/Airplay, Roon, SpotifyConnect, and many more.
The point I tried to make in that postscript – a reference to Simon’s statement further above – was simply that as far as I understand the workings of Roon some “unpacking” / bridging to the “classic” (non-Roon) audio world is still needed.