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: A method and system for flexibly and efficiently assigning channel path identifiers (CHPIDs) used by operating system software in computer systems to identify the communication path to I/O devices via channels. To avoid wasted CHPIDs, which may be limited in number, CHPIDs are assigned only to channels which are installed on and configured to the computer system. The CHPIDs may be re-assigned concurrently with ongoing system operations via a user interface and/or an imported, pre-defined CHPID mapping.

Abstract: An apparatus and method for altering the configuration of a data processing system with a plurality of processors connected in a cluster or sysplex. On one of the processors, a TSO address space with modules for defining the configuration is started. These modules are able to request details of the input/output configuration datasets (IOCDS) stored on the other processors within the cluster, amend the information and return it to the other processors where it is available for use.

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 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.