Wol: ... > X comes in two halves, the front end (or server, they use the words the > other way round to normal), ...
No, server is a software concept, a program that waits and responds to inbound calls, the X-server is just that. A client is a program/user that pokes at the server and get responses. It's just the pc hoard that thinks a server is some machine handling databases, mail, files, printers or whatever. It has noting to do with what is there or here. Regards, /Karl Hammar