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: In one embodiment, a computer-implemented method includes making a determination, by a computer, to perform a transforming operation on a shared volume. A notify command is sent to a storage controller of the shared volume, the notify command including an action to be taken by other hosts connected to the shared volume. A message is received from the storage controller, the message indicating that responses have been received from the other host systems connected to the shared volume. A determination is made as to whether to perform the transforming operation based on the responses. The transforming operation is performed on the shared volume in response to the responses from the other host systems indicating that the other host systems successfully performed the action specified in the notify command.

Abstract: A method for utilizing parallel paths of differing performance to improve efficiency is disclosed. In one embodiment, such a method includes transmitting, over a faster path, a first command to perform first actions intended to improve efficiency of second actions associated with a second command. The method transmits, over a slower path in parallel with the faster path, the second command. Alternatively, a method for utilizing parallel paths of differing performance to improve efficiency includes receiving, over a faster path, a first command to perform first actions intended to improve efficiency of second actions associated with a second command. The method executes the first command to perform the first actions. The method receives, over a slower path in parallel with the faster path, the second command and executes the second command to perform the second actions. Corresponding systems and computer program products are also disclosed.

Abstract: In an approach for establishing metadata for one or more primary devices in a mirroring relationship, one or more computers systems generate a device validity token and establish a mirroring relationship, wherein the mirroring relationship includes identifying one or more primary devices of a plurality of devices in the mirroring relationship. The approach includes the computer systems sending the device validity token to each of a plurality of operating systems in the mirroring relationship for storage in a token store and retrieving a logical device identifier for each of the devices in the mirroring relationship. Furthermore, the approach includes the computer systems generating metadata for each of the primary devices, wherein metadata for each of the one or more primary devices includes at least the device validity token and the logical device identifier for each primary device of the one or more primary devices that generates the metadata.

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: Embodiments include method, systems and computer program products for resource management of untrusted programs. In some embodiments, a first request to process an asynchronous event by an untrusted application may be received. The first request may include a host memory address. A counter may be incremented in response to receiving the first request. A device memory address may be retrieved from a device translation table using the host memory address. Processing the first request by a device using the device memory address may be facilitated. A second request to unregister the host memory address may be received. The counter may be determined to be non-zero. An action may be implemented in response to determining that the counter is non-zero.

Abstract: A method, system, and computer program product are described for a machine selecting a selected adapter among two or more adapters that perform a same function. The method includes generating a request, at the machine, for the function, and calculating a time indicator associated with each of the two or more adapters based on a respective adapter queue time factor (QTF) associated with each of the two or more adapters, the adapter QTF associated with each of the two or more adapters being a computed value. The method also includes selecting the selected adapter and submitting one or more requests to the selected adapter of the two or more adapters to perform the function based on a comparison of the time indicator associated with each of the two or more adapters.

Abstract: A method, system, and computer program product are described for a machine selecting a selected adapter among two or more adapters that perform a same function. The method includes generating a request, at the machine, for the function, and calculating a time indicator associated with each of the two or more adapters based on a respective adapter queue time factor (QTF) associated with each of the two or more adapters, the adapter QTF associated with each of the two or more adapters being a computed value. The method also includes selecting the selected adapter and submitting one or more requests to the selected adapter of the two or more adapters to perform the function based on a comparison of the time indicator associated with each of the two or more adapters.

Abstract: Aspects include a computer-implemented method for managing alias devices across logical control units. Aspects include establishing one or more alias management groups associated with a set of one or more logical control units. Aspects also include responsive to one or more changes to the set of network paths of a first logical control unit in the set of logical control units performing a method comprising: marking a first alias management group associated with the first logical control unit as invalid for alias borrowing. Then, performing a first synchronized CPU enablement operation that ensures each of the plurality of CPUs has enabled. Aspects include determining whether a second alias management group exists having a second set of control units that matches the set of paths of the first control unit and associating the first control unit with the second alias management group.

Abstract: An I/O processing system includes an operating system configured to control an input/output (I/O) device, which executes an I/O operation in the I/O processing system. The I/O processing system further includes a channel subsystem module configured to output an interrogation command signal while the I/O device executes an I/O request. The I/O device returns an I/O status signal indicating a status of an ongoing I/O request, and the operating system is configured to dynamically determine a timeout event of the I/O request based on the status of the ongoing I/O request.

Abstract: A computer program product is provided for storage controller-mediated volume transformation in a shared-resource environment. The computer program product comprises a computer readable storage medium having program instructions embodied therewith. The program instructions are executable by a computer to cause the computer to receive, from an initiating host system, a command to send a notification to other host systems connected to a shared volume. Additionally, the programs instructions are executable by the computer to cause the computer to broadcast an interrupt to the other host systems connected to the shared volume, and receive responses from the other host systems connected to the shared volume. Moreover, the programs instructions are executable by the computer to cause the computer to notify the initiating host system of the responses received from the other host systems connected to the shared volume.

Abstract: A method, system, and computer program product are described for a machine selecting a selected adapter among two or more adapters that perform a same function. The method includes generating a request, at the machine, for the function, and calculating a time indicator associated with each of the two or more adapters based on a respective adapter queue time factor (QTF) associated with each of the two or more adapters, the adapter QTF associated with each of the two or more adapters being a computed value. The method also includes selecting the selected adapter and submitting one or more requests to the selected adapter of the two or more adapters to perform the function based on a comparison of the time indicator associated with each of the two or more adapters.

Abstract: A method, system, and computer program product are described for a machine selecting a selected adapter among two or more adapters that perform a same function. The method includes generating a request, at the machine, for the function, and calculating a time indicator associated with each of the two or more adapters based on a respective adapter queue time factor (QTF) associated with each of the two or more adapters, the adapter QTF associated with each of the two or more adapters being a computed value. The method also includes selecting the selected adapter and submitting one or more requests to the selected adapter of the two or more adapters to perform the function based on a comparison of the time indicator associated with each of the two or more adapters.

Abstract: A computer-implemented method for determining correct devices to use in a mass volume migration environment includes reading an I/O configuration definition for a plurality of devices in the mass volume migration environment and definition of a second set of the plurality of devices, wherein the plurality of devices comprise a first set of the plurality of devices. The method includes executing a migration and annotating the first set and the second set with status identifiers. The method also includes responsive to completing a migration of a device in the first set to the associated corresponding device in the second set, updating the annotation of the migrated device in the first set and the corresponding device in the second set and swapping the migrated device in the first set with the corresponding device in the second set, and continuing the migration of devices of the first set to the second set.

Abstract: A system and method of implementing a firm channel in a computer system are provided. The method including identifying at least one of a channel and a channel path ID (CHPID) as a first firm channel, automatically defining a logical path between a first device and a second device using the first firm channel, and storing the logical path in a configuration file of the computer system, wherein the logical path is accessible at system initialization.

Abstract: Embodiments include method, systems and computer program products for resource management of untrusted programs. In some embodiments, a first request to process an asynchronous event by an untrusted application may be received. The first request may include a host memory address. A counter may be incremented in response to receiving the first request. A device memory address may be retrieved from a device translation table using the host memory address. Processing the first request by a device using the device memory address may be facilitated. A second request to unregister the host memory address may be received. The counter may be determined to be non-zero. An action may be implemented in response to determining that the counter is non-zero.

Abstract: A computer-implemented method includes identifying a computer storage environment comprising a primary storage device and one or more secondary storage devices and determining a secondary data retrieval scenario associated with one of the one or more secondary storage devices. The computer-implemented method further includes determining a read-only retrieval arrangement based on the secondary data retrieval scenario. A corresponding computer program product and computer system are also disclosed.

Abstract: A method, system, and computer program product are provided for determining whether a control unit for an attached device has lost knowledge of a supported host enabled facility associated with the attached device. I/O instructions are initiated that include a first instruction to determine whether the control unit currently has knowledge of the host enabled facility and a second instruction providing knowledge of the host enabled facility by the control unit. Based on responses from the control unit to the I/O instructions, it is determined whether the control unit has transitioned from not having knowledge of the host enabled facility to having such access. If it is determined that the control unit has made such transition as a result of the sequence of I/O instructions, parameters for use with the host enabled facility are initialized; otherwise, such initialization is prevented.

Abstract: Embodiments of the present invention provide systems, methods, and computer program products for managing computing devices to handle an input/output (I/O) request. In one embodiment, the I/O request may eligible for performance throttling based, at least in part, on the associated importance level for performing the received I/O request and one or more characteristics of the received I/O request. Embodiments of the present invention provide systems, methods, and computer program products for throttling the I/O request and transmitting the I/O request to a storage controller.

Abstract: Embodiments include method, systems and computer program products for resource management of untrusted programs. In some embodiments, a first request to process an asynchronous event by an untrusted application may be received. The first request may include a host memory address. A counter may be incremented in response to receiving the first request. A device memory address may be retrieved from a device translation table using the host memory address. Processing the first request by a device using the device memory address may be facilitated. A second request to unregister the host memory address may be received. The counter may be determined to be non-zero. An action may be implemented in response to determining that the counter is non-zero.