The reason I started wondering about concurrent calls to drmaa_wait() is that Peter and I have been discussing what it would take to add an event mechanism to the OO spec. Given that OO languages are generally inherently multi-threaded, any developer could write his own event mechanism by adding a thread that does the following: while (true) { JobInfo info = Session.wait (JOB_IDS_SESSION_ANY, TIMEOUT_WAIT_FOREVER); JobEvent e = new JobFinishedEvent (info); fireJobEvent (e); } Clients could then register for events. (This, BTW, functions without a race condition.) The question is why developers should have to implement that themselves when we could easily add it to the OO spec. Let's not fight over who gets to be the first to explain why we can't do this! ;) Daniel