SYNCHRONOUS INPUT/OUTPUT USING A LOW LATENCY STORAGE CONTROLLER CONNECTION

Aspects include transmitting a synchronous I/O command to a persistent storage control unit (SCU in response to a synchronous I/O request from an operating system (OS). A unit of work in the OS corresponding to the synchronous I/O request remains active at least until the synchronous I/O request is completed. Based on an operation code of the synchronous I/O command specifying a read operation and in response to detecting that the persistent SCU has stored one or more read data records in a memory located on the processor, the firmware indicates to the OS that the synchronous I/O request is completed. Based on the operation code specifying a write operation and in response to detecting an indication from the persistent SCU that write data has been written or indicating that an error has occurred, indicating to the OS that the synchronous I/O request is completed.