Abstract: Aspects include communicating synchronous input/output (I/O) commands between a system and a recipient. The system executes on a processor coupled to a memory so as to issue, to the recipient, a synchronous I/O command with a diagnostic operation code, where the synchronous I/O command causes a gathering of diagnostic information by the recipient. Further, the system receives, from the recipient, status information including a diagnostic information identifier, the status information being in accordance with the diagnostic information.