It's not that total actually. Of course we cannot always clearly and formally distinguish bare metal server from virtual server, and both of them from just a se

It's not that total actually. Of course we cannot always clearly and formally distinguish bare metal server from virtual server, and both of them from just a server program coexisting on workstation or laptop with other programs. But when I say 'a bunch of server racks', you know what I mean, don't you? BTW AFAIK a server in X Window System is called 'server' because it does 'listen', so formally it is, and so it wasn't a question back then.