You will probably have noticed that for individual seatback entertainment systems, they are frequently some kind of Sony hardware Linux implementation from the bootup sequence... I don't know whether the computer is in the seat unit itself, or in some central bay. I hope that the storage is certainly shared between all the seats!
I thought it was Panasonic Avionics hardware running Linux. Based on what I've seen I've assumed that the computer was under the seat in that electronics, and speaking Ethernet (or the Aviation Ethernet equivalent who's name I can't remember at the moment) to storage and master control in the E/E bay.
I've also seen both these and the LiveTV systems fail to obtain an IP address and put themselves into a short reboot loop until they eventually pick one up.
I've managed to "crash my seat" at least twice (once on a TATL pmUA 772, and on a lieflat 752 ORD-IAH) which always amuses me...