It is a terminal server, with thin clients connected to it via a "dumb" machine (offers basic networking, video and mouse/keyboard input). Everything is living off of one server that everyone shares, and is therefore managed by an IT department. The clients connect (usually) with the RDP (Remote Desktop Protocol) used by Windows Servers, although there are some that use VNC or other remote technologies. The main point though is that the devices that connect the keyboard mouse and monitor are not processing anything themselves, but rather, sending all input to the server, and taking in the output for the screen.