There were two server installation types prior to Windows Server 2012: full and core. Core servers provide a low attack surface by removing the Windows Shell and Internet Explorer completely. However, it presented quite a challenge for many Windows administrators as Windows PowerShell and command line utilities were the only methods used to manage the servers and its roles locally (you could use most management consoles remotely).
Those same two server installation types return in Windows Server 2012; however, we have added a third installation type: Minimal Server Interface.
See the full post at http://blogs.technet.com/b/askds/archive/2012/09/20/windows-server-2012-shell-game.aspx.