International Business Machines Corporation

Allan Samuel Meritt

Harry M Yudenfriend

Kenneth J Oakes

Steven G Glassen

Marten J Halma

Leslie W Wyman

Eugene P Hefferon

Frank William Brice

Donald W Schmidt

Charles W Gainey, Jr

Jeffrey Mark Nick

Jeffrey Paul Kubala

Beth A Glendening

John S Trotter

Tan Lu

Charles E Shapley

William C Shepard

Hans-Helge Lehmann

Daniel Francis Casper

Brent Cameron Beardsley

Bruce H Ratcliff

Robert Edward Galbraith

David Harold Surman

Stephen R Valley

Michael D Swanson

Janet R Easton

Arthur James Stagg

Michael E Baskey

Thomas Edward Cook

Joseph C Elliott

Martin W Sachs

Kenneth J Fredericks

Anthony R Sager

Michael Aloysius Paulsen

Assaf Marron

Thomas Anthony Gregg

David F Craddock

Giles R Frazier

David Arlen Elko

Bruce Marshall Walk

Richard Louis Arndt

Jeffrey Alan Frey

Bruce Leroy Beukema

Ronald Edward Fuhs

Casper A Scalzi

Robert J Dugan

Roger E Hough

Brian B Moore

Steven Lyn Rogers

Paul J Brown

David E Stucki

John F Betz

Calvin Charles Paynton

Larry Richard Perry

John F Isenberg, Jr

Frank W Brice

Richard R Guyette

Theodore R Maeurer

Glenn W Sears, Jr

Francis E Johnson

Mark J Fantacone

Lisa M Goetze

Juergen Erwin Maergner

Mark C Snedaker

Suzanne M John

Gerald T Moffitt

John C Rathjen, Jr

Paul A Malinowski

Andrea Lynn Sheber

Stephen R Newson

Eddie T Hall

Ugochukwo Njoku-Charles

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.

Multiple logical input/output subsystem facility

A computer implemented method, data processing system, and computer usable program code are provided for using identifier virtualization to extend the virtualization capabilities of protocols. A determination is made as to whether a logical entity requires a unique identifier in order to extend a virtualization capability of a protocol. A unique name is assigned that is associated with the logical entity. The unique identifier is requested from a fabric using the unique name. The logical entity is notified that the unique identifier has been established for the logical entity in response to receiving the unique identifier from the fabric. The unique identifier identifies the logical entity within or attached to the fabric.

[object Object]

An apparatus, system and method for providing multiple logical partitions in a system area network are provided Logical partitioning support is provided for host channel adapters which allows multiple operating systems to share the resources of a single physical host channel adapter (HCA). The apparatus, system and method ensures that each operating system is unaware that the HCA hardware resources are being shared with other operating systems and further guarantees that the individual operating systems are prevented from accessing HCA hardware resources which are associated with other operating systems.

Apparatus, system and method for providing multiple logical channel adapters within a single physical channel adapter in a system area network

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.

Sharing communications adapters across a plurality of input/output subsystem images

The utilization of various individual components of a channel is determined in order to learn which portion of a channel is busy and to what extent that portion is busy. The determination of a component's utilization is dependent on the type of component, as well as the operational characteristics of that component.

Measuring utilization of individual components of channels

Asynchronous requests, such as input/output (I/O) requests, within a coprocessor of a computing environment are managed. The management of the asynchronous requests is based on priorities associated with the asynchronous requests. This management includes, for instance, selecting an asynchronous request to be processed using a priority scheme, and/or affording resources to the asynchronous requests using a priority scheme.

Processing channel subsystem pending I/O work queues based on priorities

A method of providing direct data processing access in a network computing system environment. The system environment has a main storage which can be connected to one or more application servers and is in processing communication with an interface element. The interface element has at least one adapter and can be connected to one or more application user(s). One or more queues are established in the main storage that can handle data without causing interrupts in the running programs. Incoming data is received using the adapter and as data is received or modified, the status of the network computing system will be updated to reflect the new data or change. Data is then processed in the main storage after interrogating the multiple existing queues in the main storage and forwarding them in turn to their appropriate destination or application server after a determination has been made by interrogating these queues.

Method of providing direct data processing access using a queued direct input-output device

A queuing method and apparatus for transfer or incoming and outgoing data in a network environment having a main storage is presented. A plurality of queue sets are provided in the main storage with at least one or more sets being dedicated for input and output. The queues can share access to a plurality of devices in the network across a plurality of communication stacks. Various network resources are mapped to the queues in order to facilitate resource allocation and dynamic configuration by providing initialization of a plurality of configuration parameters. In this way dynamic expanding and contracting of the number of queues in each set as dictated by traffic patterns and feedback indicators is provided.

Queuing method and apparatus for providing direct data processing access using a queued direct input-output device

Disclosed is a system for dynamically assigning alias addresses to base addresses referencing an I/O device, such as a direct access storage device (DASD). In the system, at least one base control block indicates a base address and a plurality of alias control blocks indicate a plurality of alias addresses. Each control block is associated with an address for addressing an I/O device. A processing unit, such as a host computer system, processes at least one alias control block associated with the I/O device and determines a base control block associated with the I/O device with which the alias control blocks are associated. The processing unit then binds at least one alias control block to the determined base control block. The bound base and alias control blocks provide different addresses to address the same I/O device. Further, the bound base and alias addresses address the same I/O device for subsequent I/O operations until the processing unit detects a reassignment of the association of base and alias addresses.

Method and system for dynamically assigning addresses to an input/output device

Disclosed is a system for reassigning addresses. A first processing unit, such as a storage controller, provides at least two base addresses for addressing devices, such as volumes of a direct access storage device (DASD) and a plurality of alias addresses. An alias address associated with a base address provides an address for addressing the device addressed by the base address. The first processing unit processes a command transmitted from a second processing unit, such as a host system that accesses the DASD through the storage controller, to reassign an alias address from a first base address to a second base address. The first base address addresses a first device and the second base address addresses a second device. The first processing unit then indicates that the alias address to reassign is not associated with the first base address and is associated with the second base address. The second device addressed by the second base addresses is capable of being addressed by the reassigned alias address. The first processing unit signals the second processing unit after the first processing unit indicates that the alias address was reassigned from the first base address to the second base address.

System for reassigning alias addresses to an input/output device

A dynamic switch connects a control unit to a plurality of channels on one or more processors, each processor controlled by an operating system. A logical path scheduler (LPS) within a master operating system in one of the processors contains a path control table which contains an entry for each control unit, system, and logical path combination--each entry indicating current path status (connected or disconnected), and time in that status. I/O requests within the systems for which no path currently exists are queued, and the LPS initiates connections and disconnections for the paths to equitably allocate the maximum number of simultaneous path connections allowed for the control unit, among more than that maximum number of contending channels.

Logical path scheduler for disconnecting currently connected paths to

Execution of input/output operations is controlled by one or more suspend and/or resume mechanisms. Suspension of an input/output operation is accomplished by one of a number of mechanisms including, for instance, a START SUBCHANNEL instruction with execution limits, a SUSPEND SUBCHANNEL instruction with or without a suspension time limit, or a suspend subchannel channel command word with or without a suspension time limit. Subsequent to suspending execution of a channel program, execution can be resumed automatically or by issuing a RESUME SUBCHANNEL instruction with limits or a resume subchannel channel command word with limits.

Method and system for predefined suspension and resumption control over

Coupling execution of channel programs without central processing unit supervision controls data transfer between input/output devices through a main storage of a data processing system. In one embodiment, channel programs to be coupled are generated by a program running on a data processing system central processing unit. The channel program on the input subchannel includes channel commands referencing the output subchannel and operating to cause resumption of the output subchannel. The channel program on the output subchannel includes suspend channel commands directed to itself which correspond to the resume channel commands in the channel program on the input subchannel. In alternative embodiments values in channel commands can change values in, or reference, control blocks to effect execution of other channel programs.

System for coordinating execution of multiple concurrent channel

Disclosed is a data processing system for presenting concurrent requests for access to peripheral devices up to the number of subchannels available for handling input/output operations. A computer system provides a plurality of subchannels and affiliated unit control blocks for input/output operations between main storage and the peripheral devices. The unit control blocks comprise two groups, including a first dedicated to the peripheral devices and a second group available for dynamic association with the peripheral devices on a demand basis. The unit control blocks are termed base unit control blocks and alias unit control blocks, respectively. Upon system initialization, alias unit control blocks for a given logical subsystem are linked in a free pool. To initiate an input/output operation a program executing on the CPU first queries a base unit control block for a target peripheral device to determine its availability. If available, the base unit control block and associated base subchannel are used for the input/output operation. If not, determination is made if an alias unit control block may be used and if any are available. Responsive to affirmative determinations, an alias unit control block is removed from the free pool and is linked to the base unit control device for the target peripheral device in an exposure chain. The CPU then places a channel program in main storage including a prefix channel command for binding an alias address for the alias unit control block with a particular device. This is done by passing the binding command to a controller for the target peripheral device which maintains tables of affiliations between aliases and peripheral devices on a path group basis. After binding, the input/output operation proceeds in conventional fashion.

System for dynamic association of a variable number of device addresses

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Poughkeepsie, NY, United States of America

Allan Samuel Meritt