Abstract: 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.

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: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

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.