Xi

xi is the node which has the direct connection to the outside world; all the other nodes connect to the rest of the world via the BluePC network. It is never powered off.

It also runs the Web server for the whole cluster (thus also the pages which you're currently viewing) and also the single use password authentication service which allows users to connect via SSH from the Internet to the cluster.

It also has serial connections to the APC UPS as well as the Cisco Catalyst switch for the Wall rack. It also has a monitor and keyboard available in the EA D02 room.