Abstract: A method for verifying an input/output (I/O) hardware configuration is provided. A verification command is processed. The verification command includes a software device address range associated with a logical control unit (LCU) of the I/O hardware. The LCU utilizes a first logical path. The software device address range utilizing the first logical path is compared with an existing software device address range utilizing at least one additional logical path. The verification command is accepted if the software device address range and the existing software device address range match.

Abstract: A host reserves a device controlled by a controller that is coupled to the host. The controller starts a first timer, in response to a completion of input/output (I/O) operations on the device by the host, wherein the host continues to reserve the device after the completion of the I/O operations. The controller sends a notification to the host after an expiry of the first timer, wherein the notification requests the host to determine whether the device should continue to be reserved by the host. The controller starts a second timer, in response to receiving an acknowledgement from the host that the notification has been received by the host, wherein reservation status of the device reserved by the host is determined by the controller on or prior to an expiry of the second timer.

Abstract: A method to preserve a logical communication path in a data processing system, that includes a host computer, a storage controller that comprises a first logical control unit (“LCU”), and a logical communication path that is in communication with the host computer and the first LCU, comprising deleting the first LCU and setting a first status for same. The method then configures a second LCU, and establishes a second status for same, wherein the second LCU includes all or a portion of the first LCU, but is not the same as the first LCU. The deleting, setting, configuring, and establishing are performed while maintaining the logical communication path, which is in communication with the second LCU.

Abstract: A host reserves a device controlled by a controller that is coupled to the host. The controller starts a first timer, in response to a completion of input/output (I/O) operations on the device by the host, wherein the host continues to reserve the device after the completion of the I/O operations. The controller sends a notification to the host after an expiry of the first timer, wherein the notification requests the host to determine whether the device should continue to be reserved by the host. The controller starts a second timer, in response to receiving an acknowledgement from the host that the notification has been received by the host, wherein reservation status of the device reserved by the host is determined by the controller on or prior to an expiry of the second timer.

Abstract: A method to preserve a logical communication path in a data processing system, that includes a host computer, a storage controller that comprises a first logical control unit (“LCU”), and a logical communication path that is in communication with the host computer and the first LCU, comprising deleting the first LCU and setting a first status for same. The method then configures a second LCU, and establishes a second status for same, wherein the second LCU includes all or a portion of the first LCU, but is not the same as the first LCU. The deleting, setting, configuring, and establishing are performed while maintaining the logical communication path, which is in communication with the second LCU.

Abstract: A method for verifying an input/output (I/O) hardware configuration is provided. A verification command is processed. The verification command includes a software device address range associated with a logical control unit (LCU) of the I/O hardware. The LCU utilizes a first logical path. The software device address range utilizing the first logical path is compared with an existing software device address range utilizing at least one additional logical path. The verification command is accepted if the software device address range and the existing software device address range match.