someone removed the network connector from fb0. My guess is that that happened by accident the last time someone moved the rack. fb0 is not mounted in the rack right now so the main network cable is a bit short. If the rack is moved to far you kill the main network connection by pulling the plug. This of course kills the computer as the RT core and the frontend code is mounted using nfs located on fb1. Same for doing simple commands like ls. The system stops working as soon as you try to access data from a mounted nfs directory which doesn't exist anymore. After reconnecting the network everything was fine. However in order to avoid problems i rebooted the machine...Both frontend codes, atf and psl are back online...