I am facing a problem in java rmi. Actually the scenario is that i am working on a project which is about "computer lab reservation" of my university where students reserve pc's for their use for a specific time plus there are also some other constraints. But one of its constraint is that the server itself has to mantain the list of working pcs in the lab. The operating systems present in the lab are windows2000 and winNT4. I thought that the server will keep on sending pings to the clients and if it gets the response, that means the cliet pc is in the working state. Till here its ok. But Problem lies where the condition is that the client pc is in the logoff mode so our client application wont be running on the client side. then how can the server check that whether the client pc is working or out of order becoz in the logoff mode our application wont be running. so i need help in this regard that what should the server application do in order to know that client pc's are working or not. I mean when the system is shutdown then nothing can be done, but when it is in the logoff mode then that means plz if you have anything regarding it or just have a hint then mail me on the following address email@example.com.