The DD statements named T0000001 to T000000n with n=NUMTCB from the scheduler configuration contain the messages issued by the numbered working task running in the scheduler address space. These tasks get woken up by the main task to fulfil the requests coming in from clients.
During startup, important control block addresses and configuration parameters used are listed. The worker task successfully initialized when this message is issued:
TAU0142I hh:mm:ss.ttt z/Server subtask READY for clients
After startup, it shows which client the worker task was active for. First it acknowledges that it was activated and then it lists what it was activated for. A typical example would look like this:
TAU0023I hh:mm:ss.ttt Subtask for z/Server activated SLR0107I hh:mm:ss.ttt Deferred LOGON for user userid successful