Abstract: Provided are a method, system, and program for managing path groups to an Input/Output (I/O) device. Indication is made of a connection path on which a processing system initially communicated an establish request to establish a connection with an I/O device, wherein attention that the processing system may own a lock for the I/O device is transmitted down the indicated connection path. A request is received from the processing system to add a path to a path group with respect to the I/O device, wherein the added path is capable of comprising the connection path the processing system used to establish the connection with the I/O device. The received path is added to the path group.

Abstract: A system is disclosed that includes a host system to issue a write command, a primary storage device to write data to a primary volume, and a secondary storage device to mirror the data to a secondary volume. A task timer may be initiated upon sending the data from the primary storage device to the secondary storage device. The secondary storage device may also send an acknowledge signal to the primary storage device in the event it successfully mirrors the data to the secondary volume. In the event the acknowledge signal is not received before the timer expires, the primary storage device may notify the host system that the primary and secondary volumes are in a suspended state. To alter the duration of the timer, the host system may be further configured to dynamically alter the duration of the timer by sending a command to the primary storage device.

Abstract: A system is disclosed that includes a host system to issue a write command, a primary storage controller to write data to a primary volume, and a secondary storage controller to mirror the data to a secondary volume. In the event the secondary storage controller is unable to mirror the data due to a busy state, a busy signal may be sent to the primary storage controller. The primary storage controller may initiate a timer in the event it receives the busy signal, and, in the event the busy state does not end before expiration of the timer, notify the host system that the primary and secondary volumes are in a suspended state. To alter the duration of the timer, the host system may be configured to dynamically alter the duration of the timer by sending a command to the primary storage controller.

Abstract: A method is disclosed to control access to stored information. The method supplies a control unit in communication with a computing device and in communication with stored information. If the computing device requests access to that stored information, the method determines if access to the stored information is available. When access to the stored information becomes available, then the method reserves a communication pathway interconnecting the control unit and the requesting computing device, thereby disallowing the sending of non-MPLF unsolicited status via that reserved communication pathway, and provides a message to the computing device, using that reserved communication pathway, granting access to the stored information.

Abstract: Provided are a method, system, and article of manufacture for assigning alias addresses to base addresses. An assignment is provided of base addresses to the devices. The base addresses are used to access the devices assigned to the base addresses. An assignment is provided of a plurality of alias addresses to an alias address pool. The alias addresses in the alias address pool are capable of being dynamically assigned to the devices to service I/O requests to the devices. An Input/Output (I/O) request to access one target device comprising one of the devices is processed. A determination is made as to whether the base address assigned to the target device is available. One alias address is assigned to the target device in response to determining that the base address is not available. The I/O request is issued to the assigned alias address to transmit the request to the target device.

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: Provided are techniques for retrieving lock attention data. A group of attention connection paths configured to transmit lock attention interrupts and lock attention data between the host and the control unit are identified. A lock attention interrupt is received from the control unit. In response to receiving the lock attention interrupt, a connection path from the group of attention connection paths is selected and lock attention data is retrieved from the control unit using the selected connection path.

Abstract: A method is disclosed to control access to stored information. The method supplies a control unit in communication with a computing device and in communication with stored information. If the computing device requests access to that stored information, the method determines if access to the stored information is available. When access to the stored information becomes available, then the method reserves a communication pathway interconnecting the control unit and the requesting computing device, thereby disallowing the sending of non-MPLF unsolicited status via that reserved communication pathway, and provides a message to the computing device, using that reserved communication pathway, granting access to the stored information.

Abstract: A system and method for recovering from logical path failures is set forth. More specifically, when a host detects a logical path failure, the host enters a path discovery mode of operation. If the host continues to detect a logical path failure while operating in the logical path discovery mode of operation, the host removes the logical path from a logical path mask, and the host does not use the removed logical path again. Additionally, the system and method facilitates recovery of the failed logical paths by using a plurality of logical path masks. A first mask is referred to as an intermediate failure logical path mask and a second mask is referred to as a permanent failure logical path mask.

Abstract: A method to minimize performance degradation during communication path failure in a data processing system, comprising a host computer, a storage controller, and a plurality of physical communication paths in communication with the host computer and the storage controller, where the method establishes a. threshold communication path error rate, and determines an (i)th actual communication path error rate for an (i)th physical communication path, wherein that (i)th communication path is one of the plurality of physical communication paths. If the (i)th actual communication path error rate is greater than the threshold communication path error rate, the method discontinues use of the (i)th physical communication path.

Abstract: A storage controller receives an interrupt control directive from a host. The storage controller generates a first plurality of interrupts, in response to access requests received from the host for at least one storage device coupled to the storage controller, wherein the first plurality of interrupts indicates whether access to the at least one storage device is allowed to the host. The storage controller generates a second plurality of interrupts, wherein the second plurality of interrupts comprises unsolicited interrupts for the host that are different from the first plurality of interrupts. The storage controller controls how many of the first plurality of interrupts and how many of the second plurality interrupts to send to the host, based on the received interrupt control directive.

Abstract: A storage controller receives an interrupt control directive from a host. The storage controller generates a first plurality of interrupts, in response to access requests received from the host for at least one storage device coupled to the storage controller, wherein the first plurality of interrupts indicates whether access to the at least one storage device is allowed to the host. The storage controller generates a second plurality of interrupts, wherein the second plurality of interrupts comprises unsolicited interrupts for the host that are different from the first plurality of interrupts. The storage controller controls how many of the first plurality of interrupts and how many of the second plurality interrupts to send to the host, based on the received interrupt control directive.

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: An apparatus, system, and method are disclosed to prevent queue stalling. The apparatus to prevent queue stalling is provided with a plurality of modules configured to functionally execute the necessary steps of detecting a connection failure on a first logical path, wherein the first logical path is associated with a first entry in a queue, and wherein the first logical path is configured to define a communication path between an entity associated with a first entry in the queue and a queue manager, scanning the queue to identify a second entry associated with a second logical path in response to the connection failure, and advancing the second entry to a position within the queue that is ahead of the first entry. These modules in the described embodiments include a detection module, a scanning module, and an advancing module.

Abstract: Provided is a system, deployment and program for resource allocation unit queuing in which an allocation unit associated with a task is classified. An allocation unit freed as the task ends is queued for use by another task in a queue at a selected location within the queue in accordance with the classification of said allocation unit. In one embodiment, an allocation unit is queued at a first end of the queue if classified in a first class and is queued at a second end of the queue if classified in said second class. Other embodiments are described and claimed.

Abstract: Provided are techniques for retrieving lock attention data. A group of attention connection paths configured to transmit lock attention interrupts and lock attention data between the host and the control unit are identified. A lock attention interrupt is received from the control unit.

Abstract: A system is disclosed that includes a host system to issue a write command, a primary storage device to write data to a primary volume, and a secondary storage device to mirror the data to a secondary volume. A task timer may be initiated upon sending the data from the primary storage device to the secondary storage device. The secondary storage device may also send an acknowledge signal to the primary storage device in the event it successfully mirrors the data to the secondary volume. In the event the acknowledge signal is not received before the timer expires, the primary storage device may notify the host system that the primary and secondary volumes are in a suspended state. To alter the duration of the timer, the host system may be further configured to dynamically alter the duration of the timer by sending a command to the primary storage device.

Abstract: A system is disclosed that includes a host system to issue a write command, a primary storage controller to write data to a primary volume, and a secondary storage controller to mirror the data to a secondary volume. In the event the secondary storage controller is unable to mirror the data due to a busy state, a busy signal may be sent to the primary storage controller. The primary storage controller may initiate a timer in the event it receives the busy signal, and, in the event the busy state does not end before expiration of the timer, notify the host system that the primary and secondary volumes are in a suspended state. To alter the duration of the timer, the host system may be configured to dynamically alter the duration of the timer by sending a command to the primary storage controller.

Abstract: An apparatus, system, and method are disclosed for grouping connection paths for lock attention data. A grouping request module is included to receive a request to establish a group of connection paths. Each connection path is configured to communicate lock attention data between a host and a control unit. The control unit is configured to control a storage device containing data accessible to a plurality of processes. A connection path selection module is included to select a plurality of connection paths between the host and the control unit and a grouping assignment module configured to assign the plurality of connection paths to a group. In one embodiment, an attention selection module is included to select an attention connection path for communicating lock attention data from any of the connection paths in the group. The attention selection module may select an attention connection path using a load balancing function.

Abstract: Provided is a method, system, deployment and program for resource allocation unit queuing in which an allocation unit associated with a task is classified. An allocation unit freed as the task ends is queued for use by another task in a queue at a selected location within the queue in accordance with the classification of said allocation unit. In one embodiment, an allocation unit is queued at a first end of the queue if classified in a first class and is queued at a second end of the queue if classified in said second class. Other embodiments are described and claimed.