International Business Machines Corporation

Richard Cwiakala

Harry M Yudenfriend

Jeffrey Douglas Haggar

Kenneth J Oakes

Leslie W Wyman

Eugene P Hefferon

Charles E Shapley

David E Stucki

Mark J Fantacone

S Michael Benson

William J Rooney

Peter Bergersen Yocom

Roger E Hough

Marten J Halma

Martin W Sachs

Kenneth J Fredericks

Allen H Preston

Assaf Marron

Robert J Gallagher

Karl H Hoppe

Michael C Cox

Suzanne M John

Gary A Fisher, Sr

James C Mazurowski

David W Hollar

Miriam P Brown

Dennis D Koren

Michael Schulte

Allan S Merritt

Timothy J Spewak

Alan S Meritt

Peter I Kania

Jean-Louis Fava

Input/output (I/O) configurations of a computing environment are managed. This management includes dynamically adjusting an I/O configuration, when it is determined that such an adjustment is needed or desired. In order to make the adjustment, a channel path is selected from a plurality of channel paths. The selection of the channel path to be used in the adjustment is based on one or more characteristics associated with the channel path.

Method, system and program products for managing I/O configurations of a computing environment

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.

Asynchronous command support for shared channels for a computer complex

A computer system, including at least one host (processor and operating system), a channel subsystem and at least one switch (together with an associated switch controller) for switchably connecting an I/O device (together with an associated I/O device control unit) to a host via said channel subsystem, in combination with means for dynamically managing I/O connectivity in said computer from each host. The I/O manager's functions are centralized at the host level across the computer system. Each host is responsible for an instance of the manager. According to the preferred embodiment of the invention the computer system, I/O manager combination includes: (a) first means, located within each switch, for providing direct host access to the switch controller associated with a given switch; (b) second means, included in each host level instance of the manager, for automatically and dynamically determining the current I/O configuration and connectivity of each host; (c) third means, included in each host level instance of the manager, for performing System Integrated Switching (i.e., switching where any instance of the I/O manager can veto a proposed configuration change) and (d) fourth means, included in each host level instance of the manager, for insuring the integrity of the I/O connectivity database, through the use of an interlock mechanism, in a multiuser environment where each user can enter multiple part commands and processes concurrently.

Methods and apparatus for dynamically managing input/output (I/O)

A data processing I/O system having a main storage for storing data including a software configuration definition and data processing instructions arranged in programs including an operating system, a storage device for storing I/O definition files including hardware configuration information, a processor controller for containing the hardware configuration information, and a hardware storage area (HSA) connected to the processor controller for storing a hardware configuration definition. A hardware configuration definition program (HCD) builds I/O definition files (IODFs), each IODF containing at least one I/O processor configuration definition. Each processor I/O configuration definition has a hardware token for identification. The hardware configuration information for an I/O processor configuration definition, along with a copy of its hardware token, is transferred to the processor controller by an I/O configuration program (IOCP), and a hardware configuration definition is established in the HSA. The copy of the hardware token may be fetched from the HSA and compared to hardware token of the configuration definition used to establish the software configuration definition in the main storage to determine that the software and hardware configuration definitions are synchronized. If the software and hardware configuration definitions are synchronized, dynamic changes may be made to the hardware configuration definition in the HSA. A program parameter is provided to store recovery information such that if a failure occurs during a dynamic change, the previous hardware I/O configuration may be recovered or subsequent changes can be made from the point of failure.

Establishing synchronization of hardware and software I/O configuration

An installation creates a source I/O definition file (IODF), defining a current system I/O configuration, and a target IODF, defining a future I/O configuration. An activate function is initiated to change the system's hardware and software definition to correspond to the target IODF. A compare function compares the source and target IODFs, and creates a Configuration Change Block (CCB) to efficiently drive the change process. A validation function validates that the proposed change is valid, and the change process updates the hardware and software configuration definitions. If the change process is successful, a notification is sent; if not, a back-out process restores the I/O configuration to its initial state.

System for dynamically changing a system I/O configuration by

An installation creates a source I/O definition file (IODF), defining a current system I/O configuration, and a target IODF, defining a future I/O configuration. When the configuration definition is dynamically changed from the current to the target, a serialization mechanism--comprising a 'device pin' technique and a 'group serialization' technique to handle changed device group definitions--insures that data integrity is not lost on devices undergoing reconfiguration; and a change detection mechanism insures that changes to control structures affected by the dynamic reconfiguration, are noticed by programs accessing those control structures while the structures are changing.

Method and system for managing an operating system definition of a

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.

Dynamically changing a system I/O configuration definition

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Wappingers Falls, NY, United States of America

Richard Cwiakala