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: Enables a host (hypervisor) to access any location in any guest zone in a large memory, when host and guest operands have small addresses that cannot access locations outside of their own zones. System hardware/microcode provides a particular number of windows for host use. Each CPU in the system has one or more window access registers (WARs), and one or more window registers (WRs). The host uses a load WAR instruction to designate each page frame (PF) in the host zone to be used as a host window, and each PF is associated with a respective window number. When the host receives an interception signal requiring the host to access a guest location represented by a guest zone identifier and a guest small address, the host designates one of its window numbers for an access to this guest location.

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 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: 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.

Abstract: The embodiment provides selective supervisory disablement of fetch protection for a special storage subarea (such as for the first half of the first 4KB block) while fetch protection is enabled for an area containing the subarea by a single storage protect key. That is, the fetch protect for the subarea (normally provided in the fetch protect for the entire area) by the area's protect key is overriden by the selective subarea disablement control, so that accesses to the subarea are not fetch protected by the storage key. The override protection control is secured by its enablement via a field position in a control register only accessible to supervisory programming. Thus, while fetch protection is set on for a predefined 4KB block, the fetch protect override controls can disable the fetch protection for a portion of the block's real addresses (e.g. addresses 0-2047).