Abstract: Aspects include communicating synchronous input/output (I/O) commands between an operating system and recipient by issuing a first synchronous I/O command with an initiation bit set, identifying that a mailbox command has been initiated to return control to an operating system before waiting for operations of the first synchronous I/O command to complete, and issuing a second synchronous I/O command with a completion bit set in response to the control returning to the operating system.

Abstract: Aspects include acquiring measurement data of a synchronous input/output (I/O) link between an operating system and a recipient. The acquiring measurement data can include monitoring operating system usage of synchronous I/O commands on the synchronous I/O link and storing the operating system usage in a measurement block as the measurement data. Further, the measurement block is accessible by the operating system to determine that the measurement data is acquired.

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.

Abstract: Aspects include communicating synchronous input/output (I/O) commands between an operating system and recipient by issuing a first synchronous I/O command with an initiation bit set, identifying that a mailbox command has been initiated to return control to an operating system before waiting for operations of the first synchronous I/O command to complete, and issuing a second synchronous I/O command with a completion bit set in response to the control returning to the operating system.

Abstract: Aspects include synchronous input/output (I/O) replication of data. A synchronous I/O request is received from an operating system (OS) by firmware on a server. A plurality of synchronous I/O mailbox commands is transmitted by the firmware to a plurality of persistent storage control unit (SCU) nodes. The content of each of the plurality of synchronous I/O commands is based on the synchronous I/O request. 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. It is determined, by the firmware, that determining that each of the plurality of persistent SCU nodes have completed their respective synchronous I/O commands. Based on the determining, the firmware indicates to the OS that the synchronous I/O request is completed.

Abstract: 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.

Abstract: Aspects include sending a request to perform a unit of work that includes a synchronous I/O operation. The sending is from an operating system (OS) executing on a server to firmware located on the server. The synchronous I/O request includes a command request block that includes an operation code identifying the synchronous I/O operation and a identifier of a persistent storage control unit (SCU). The OS waits for the synchronous I/O to complete and the unit of work remains active during the waiting. The firmware detects that the synchronous I/O operation has completed. A command response block that includes completion status information about the synchronous I/O operation is received by the OS from the firmware. The unit of work is completed in response to the I/O operation completing.

Abstract: Aspects include communicating synchronous input/output (I/O) commands between an operating system and a recipient. Communicating synchronous I/O commands includes issuing a first synchronous I/O command with a first initiation bit set, where the first synchronous I/O command cause a first mailbox command to be initiated by the recipient with respect to a first storage control unit. Further, communicating synchronous I/O commands issuing a second synchronous I/O command with a second initiation bit set, where the second synchronous I/O command causes a second mailbox command to be initiated by the recipient with respect to at least one subsequent storage control unit. Communicating synchronous I/O commands also includes issuing a third synchronous I/O command with a first completion bit set in response to the first mailbox command being initiated and issuing a fourth synchronous I/O command with a second completion bit set in response to the first mailbox command being initiated.

Abstract: Aspects include providing automatic access control and security for a synchronous input/output (I/O) link. Providing automatic access control and security includes initializing devices of a storage environment over a first link to verify that the devices are available within the storage environment; building a table of identifiers, where each of the identifiers is assigned one of the devices that have been initialized; and verifying a first device attempting to perform synchronous I/O commands across the synchronization I/O link by confirming that an identifier assigned to the first device is within the table of identifiers.

Abstract: Aspects include accessing data located on peripheral devices using synchronous input/output (I/O). A unit of work is received by an operating system (OS) executing on a processor. The unit of work includes an I/O request to access data located on a persistent storage control unit (SCU) that is external to the processor. It is determined that the I/O request should be serviced by a synchronous I/O. A synchronous I/O is initiated to the persistent SCU to service the I/O request based on determining that the I/O request should be serviced by a synchronous I/O. The unit of work is kept active while waiting for the synchronous I/O to complete. A notification that the I/O has completed is received and the unit of work is completed in response to receiving the notification.

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.

Abstract: Aspects include receiving, at an operating system (OS) executing on a server, a notification that an error was detected during execution of a synchronous I/O operation issued by the OS to a persistent storage control unit (SCU). The notification is received from firmware executing on the server and it includes a command response block that includes error condition information about the error. The method can also include selecting, by the OS, a recovery operation for the synchronous I/O operation. The selecting is based on the error condition information about the error in the command response block. The selected recovery option is performed by the OS.

Abstract: Aspects include sending a request to perform a unit of work that includes a synchronous I/O operation. The sending is from an operating system (OS) executing on a server to firmware located on the server. The synchronous I/O request includes a command request block that includes an operation code identifying the synchronous I/O operation and a identifier of a persistent storage control unit (SCU). The OS waits for the synchronous I/O to complete and the unit of work remains active during the waiting. The firmware detects that the synchronous I/O operation has completed. A command response block that includes completion status information about the synchronous I/O operation is received by the OS from the firmware. The unit of work is completed in response to the I/O operation completing.

Abstract: Aspects include synchronous input/output (I/O) replication of data. A synchronous I/O request is received from an operating system (OS) by firmware on a server. A plurality of synchronous I/O mailbox commands is transmitted by the firmware to a plurality of persistent storage control unit (SCU) nodes. The content of each of the plurality of synchronous I/O commands is based on the synchronous I/O request. 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. It is determined, by the firmware, that determining that each of the plurality of persistent SCU nodes have completed their respective synchronous I/O commands. Based on the determining, the firmware indicates to the OS that the synchronous I/O request is completed.

Abstract: Aspects include accessing data located on peripheral devices using synchronous input/output (I/O). A unit of work is received by an operating system (OS) executing on a processor. The unit of work includes an I/O request to access data located on a persistent storage control unit (SCU) that is external to the processor. It is determined that the I/O request should be serviced by a synchronous I/O. A synchronous I/O is initiated to the persistent SCU to service the I/O request based on determining that the I/O request should be serviced by a synchronous I/O. The unit of work is kept active while waiting for the synchronous I/O to complete. A notification that the I/O has completed is received and the unit of work is completed in response to receiving the notification.

Abstract: Aspects include for performing an initialization sequence by a first device to execute synchronous input/output (I/O) commands across a synchronous I/O link. The initialization sequence includes posting, by the first device, a first acknowledgement in response to a register area corresponding to a second device being updated with first information according to a first synchronization sequence, the first information comprising a worldwide node name of the second device and posting, by the first device, a second acknowledgement in response the register area being updated with second information according to a second synchronization sequence, the second information comprising mailbox information. The initialization sequence also includes performing, by the first device, a third synchronization sequence to provide a worldwide node name of the first device; and performing, by the first device, a fourth synchronization sequence to provide a status area address.

Abstract: 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.

Abstract: Aspects include acquiring measurement data of a synchronous input/output (I/O) link between an operating system and a recipient. The acquiring measurement data can include monitoring operating system usage of synchronous I/O commands on the synchronous I/O link and storing the operating system usage in a measurement block as the measurement data. Further, the measurement block is accessible by the operating system to determine that the measurement data is acquired.

Abstract: Aspects include providing automatic access control and security for a synchronous input/output (I/O) link. Providing automatic access control and security includes initializing devices of a storage environment over a first link to verify that the devices are available within the storage environment; building a table of identifiers, where each of the identifiers is assigned one of the devices that have been initialized; and verifying a first device attempting to perform synchronous I/O commands across the synchronization I/O link by confirming that an identifier assigned to the first device is within the table of identifiers.

Abstract: Aspects include communicating synchronous input/output (I/O) commands between an operating system and a recipient. Communicating synchronous I/O commands includes issuing a first synchronous I/O command with a first initiation bit set, where the first synchronous I/O command cause a first mailbox command to be initiated by the recipient with respect to a first storage control unit. Further, communicating synchronous I/O commands issuing a second synchronous I/O command with a second initiation bit set, where the second synchronous I/O command causes a second mailbox command to be initiated by the recipient with respect to at least one subsequent storage control unit. Communicating synchronous I/O commands also includes issuing a third synchronous I/O command with a first completion bit set in response to the first mailbox command being initiated and issuing a fourth synchronous I/O command with a second completion bit set in response to the first mailbox command being initiated.