For the past few days I've been reading discussions about X.Org vs Mir vs Wayland and the way they differ from each other. I've read the following at Wikipedia:A display server or window server is a program whose primary task is  to coordinate the input and output of its clients to and from the rest  of the operating system, the hardware, and each other. The display  server communicates with its clients over the display server protocol,  a communications protocol, which can be network-transparent or simply  network-capable.What is the server and the client on this context? Why was the rendering process made at the server before and now the approach is to let the client worry about rendering? What was the role of the client at the old days when server did the rendering, and what is the role of the server now that the client does the rendering?I'm sorry if these are nonsensical questions. I'm really, really noob about this topic, and I just can't find any introductory material about these topics. Everything I found on internet is just too technical and complex and requires some previous background on the subject.
Server side vs Client side rendering Display server
graphics