What you describe (several operating systems running "inside or alongside
another") is virtualization. But one can simply run servers (a server is a
program accepting incoming connections from the network, nothing more) on one
single operating system, which can run desktop applications at
People on other pods will not be able to access your Diapora* page when your
computer is off.
You do not need a virtual machine. You can install the server on your system.
For instance, you can install the "openssh-server" package and you have an
SSH server running on your system.
You can install servers on your own hardware. Even low-end machines can be
more than enough. It depends on the server and on the number of clients
simultaneously connecting to your server (e.g., with a Web server, how many
visitors at the same time). If the machine is, at the same time, used
