Once the server starts, it sends a message to the window or console where you started the server indicating that the server is running.
The server also displays other information about your server environment, as well as possible problems messages on failure to start.
All server messages are written to the server log. By default, %IQLOGDIR15% is set by the installation on Windows platforms, and the server log is in %IQLOGDIR15%\servername.nnnn.srvlog, where nnnn is the number of times the server has been started. You can also use the -o startup option to name the server log.