Abstract: A communications adapter is shared by a plurality of input/output (I/O) subsystem images of an I/O subsystem of a central processing complex. To enable the sharing, the communications adapter is configured to a plurality of I/O paths of the plurality of I/O subsystem images. An I/O subsystem may have one or more shared communications adapters.

Abstract: An input/output subsystem is configured as a plurality of input/output subsystem images, each of which appears to a program as an independent input/output subsystem. An input/output subsystem image is identified by an input/output subsystem image identifier, which is used by various programs to designate the particular input/output subsystem image for which an I/O operation is to be performed. An operating system is provided with access to a plurality of input/output subsystem images of the input/output subsystem. One or more controls are provided to the operating system image to enable the operating system image to access the plurality of input/output subsystem images.

Abstract: An input/output subsystem is configured as a plurality of input/output subsystem images, each of which appears to a program as an independent input/output subsystem. In response to an operating system image submitting an input/output (I/O) request requesting access to an input/output subsystem image, a determination is made as to whether the operating system image is authorized to access the input/output subsystem image. In response to the access being authorized, the I/O request is authorized.

Abstract: An input/output subsystem is configured as a plurality of input/output subsystem images, each of which appears to a program as an independent input/output subsystem. One or more input/output subsystem images of the plurality of input/output subsystem images are managed. An aspect of this management includes managing an input/output (I/O) configuration of an input/output subsystem image. This management may be performed dynamically.

Abstract: An input/output subsystem is configured as a plurality of input/output subsystem images, each of which appears to a program as an independent input/output subsystem. An input/output subsystem image is identified by an input/output subsystem image identifier, which is used by various programs to designate the particular input/output subsystem image for which an I/O operation is to be performed. An input/output subsystem image includes, for instance, one or more input/output paths. An input/output path of an input/output subsystem image is identified by an input/output path identifier, as well as a physical input/output path identifier.

Abstract: An input/output subsystem of a computing environment is configured as a plurality of input/output subsystem images, each of which appears to a program as an independent input/output subsystem. An input/output subsystem image includes one or more communications adapters used for communicating within the computing environment. A communications adapter is identified by hardware of the computing environment by using a first identifier, and it is identified by a program of the computing environment by using a second identifier. The identifiers can be of different sizes.

Abstract: In an environment employing a fabric, such as a cascading switch network, a predictable input/output (I/O) configuration is provided. The I/O configuration explicitly specifies the one or more peripheral units accessible by a program, such as an operating system. Other peripheral units not specified in the I/O configuration are not accessible, thus, providing a secure environment.

Abstract: An apparatus, method and program product for sending data to or receiving data from one or more I/O devices in an I/O operation with a main storage controlled by a processor in a data processing system. The apparatus includes a time-of-day (TOD) register for containing a TOD value, a clock for containing a current TOD value, and a summary register having a first condition when any one of said devices requests an I/O operation and a second condition when no devices have an outstanding I/O request, each device having an outstanding I/O request sets the summary register to its first condition only when the summary register is in its second condition, and further places the current TOD value in the TOD register. A checking program determines if a specified time delay has been exceeded between the value in said TOD register and the current TOD for each requested I/O operation. The checking program drives an interrupt to the processor when the specified time delay has been exceeded.

Abstract: A method and apparatus for providing configuration information is provided in a network computing environment having a plurality of hosts and at least one Gateway attachment and a channel interface, using a QDIO device. A set of special tables and commands are provided at initialization time over the channel interface which provide all configuration information. The tables can map any Host images and Host Device Addresses which will be using the QDIO Interface to the specific bits defined in a SIGA vector, the SIGA Vector giving initiative to said QDIO connected Gateway device.

Abstract: An apparatus, method and program product for sending data to or receiving data from one or more I/O devices in an I/O operation with a main storage controlled by a processor in a data processing system. The apparatus includes a time-of-day (TOD) register for containing a TOD value, a clock for containing a current TOD value, and a summary register having a first condition when any one of said devices requests an I/O operation and a second condition when no devices have an outstanding I/O request, each device having an outstanding I/O request sets the summary register to its first condition only when the summary register is in its second condition, and further places the current TOD value in the TOD register. A checking program determines if a specified time delay has been exceeded between the value in said TOD register and the current TOD for each requested I/O operation. The checking program drives an interrupt to the processor when the specified time delay has been exceeded.

Abstract: An apparatus, method and program product for selecting paths between a main memory and I/O devices in a data processing system having a main memory for storing data, one or more I/O devices for receiving data from or sending data to the main memory, and an I/O processor (IOP) for controlling I/O operations for sending data between the main memory and the I/O devices. The data processing system includes disparate channels between the IOP and the I/O devices. The disparate channels carry data between the main memory and the I/O devices during the I/O operations. Included is a computer program executed by the IOP for assigning a path weight to selected ones of the disparate channel paths to be used in selecting the next channel path to carry data between the main memory and I/O devices. Each disparate channel type has a different set of criteria for evaluating the path weight.

Abstract: A computer program product and storage device used for exchange and transfer of data in a network computing system having a main storage capable of connecting to at least one application server and an interface element with at least one adapter capable of establishing processing communication with at least one application user(s).

Abstract: Enables any OS of plural OSs within any of plural logical-resource partitions (LPARs) of a CEC to use interpretive execution for synchronously-executable CHSC (channel subsystem call) commands. A CHSC command authorization mask (CCAM) is provided to control which CHSC commands are allowed to execute interpretively (with pass-through), and which commands are executed with hypervisor intervention (as all prior CHSC commands did). By enabling interpretive execution of those commands which can successfully operate with pass-through, significant system efficiency is obtained. And by disabling interpretive execution for a subset of CHSC commands (which are not allowed to execute with pass-through) potential system failures may be prevented. Thus, interpretive execution may be restricted differently among the OSs in a CEC. Novel CHSC command execution now handles multiple images of shared I/O resources by use of image identifiers, which could not be done before.

Abstract: A data processing I/O system including a main storage for storing data and data processing instructions arranged in software programs, and a channel subsystem having hardware for reporting conditions in the channel subsystem to the software. A special Channel Subsystem Call (CHSC) instruction is used to store event information from the channel subsystem into the main memory for use by the software such that new or restored resources such as a channel path, a channel path and partial control unit link address, or a channel path and full control unit link address, may be originally made accessible, or may be restored to the I/O system. A mechanism is also provided to inquire of a device how long it expects to not be accessible to give the device sufficient time to reset itself before it is varied offline, thus preventing a device from being isolated or "boxed" prematurely.

Abstract: This invention involves reconfiguration support for shared I/O resources in a a computer electronic complex (CEC) supporting both shared and unshared I/O channels of the type described and claimed in U.S. patent application Ser. No. 07/898,867 (PO9-92-016) filed on the same day as the subject application and assigned to the same assignee as the subject application. Prior channel subsystem call (CHSC) instructions cannot execute when a channel is to be configured as shareable by plural operating systems in a CEC.

Abstract: Provides a method for increasing the connectivity of I/O resources to a multiplicity of operating systems (OSs) running in different resource partitions of a computer electronic complex (CEC) to obtain sharing of the I/O resources among the OSs of the CEC, including channels, subchannels (devices), and control units (CUs). The invention provides image identifiers (IIDs) for assigning resources to the different OSs. Each shared I/O resource has a sharing set of control blocks (CBs) in which a respective CB is assigned to (and located by) a respective IID of one of the OSs. Each of the CBs in a sharing set provides a different image of the same I/O resource. The different CB images are independently set to different states by I/O operations for the different OSs, so that the OSs can independently share the same I/O resource.

Abstract: Provides a method for measuring the busy utilization time for I/O channel used by any of plural operating systems (OSs) in a CEC. The measured utilization time for any OS excludes the time shared channels are utilized by other OSs during a measurement period. A channel measurement facility (CMF) is provided in the I/O subsystem hardware and microcode for each of the OSs in the I/O subsystem. The CMF is logically constructed because it uses only a small portion of I/O resources already existing in a CEC by adding microcode to control these resources to perform the time measurement function. The resources for a logical CMF including the partial use of: an I/O processor to store identifiers of an assigned OS, the partial use of channel processors controlling channels selected by the assigned OS during a measurement period, the local storage of each I/O processor, and OS storage needed for communicating the measurement data from the CMF to the OS.

Abstract: A mechanism for changing the system I/O configuration definition in the channel subsystem of a data processing system without having to do a power on reset operation. The data processing system includes one or more central processing units, an I/O processor, a storage addressable by the central processors and the I/O processor, and a command mechanism for creating command-request blocks in the storage, each of which contains a requested command and data for the I/O Processor to add, delete or change elements of the I/O configuration definitions of the channel subsystem. Response-blocks are created in the storage for passing status information from the I/O processor to the central processing unit(s) indicating either successful execution of the requested command or that the I/O configuration definitions were unchanged by the command of the request-block, or when associated functions may have been performed in the execution of the command of the request-block by the I/O processor.