International Business Machines Corporation

Ugochukwu Charles Njoku

Matthew J Kalos

John R Flanagan

Daniel Francis Casper

Gustav E Sittmann, Iii

Catherine C Huang

Dale Francis Riedy, Jr

Charles W Gainey, Jr

Harry M Yudenfriend

David F Craddock

Roger Gregory Hathorn

Scott M Carlson

Mark P Bendyk

Thomas Anthony Gregg

Beth A Glendening

Donald W Schmidt

Mark S Farrell

Louis William Ricci

Frank William Brice

Anthony F Coneski

Gustav E Sittmann

Richard K Errickson

Louis C Ricci

Dan F Greiner

Damian Leo Osisek

Peter Kenneth Szwed

Janet R Easton

Tan Lu

Stephen G Wilkins

Gustav Sittmann Iii

A computer program product for processing input/output (I/O) data is provided for performing a method that includes receiving a transport control word (TCW) including an indirect data address including a starting location of a transport mode indirect data address list (TIDAL) of storage addresses, the TIDAL including a plurality of entries configured as transport mode indirect data address words (TIDAWs). The method includes accessing an entry of the TIDAL, which includes: 1) based on the entry of the TIDAL indicating that the address is a data address, gathering data from a data storage location corresponding to the data address, and accessing a next entry of the TIDAL, and 2) based on the entry of the TIDAL indicating that the address is an address of a next entry of the TIDAL, obtaining the next entry of the TIDAL from another storage location that is located non-contiguously to the entry storage location.

Providing indirect data addressing in an input/output processing system where the indirect data address list is non-contiguous

A computer program product for processing input/output (I/O) data is provided for performing a method, which includes receiving a control word having an indirect data address including a starting location of a list of storage addresses, gathering the data and transmitting gathered data to a control unit in the I/O processing system. Gathering includes accessing an entry of the list, the entry located at an entry storage location and including an address. Based on the entry of the list indicating that the address is a data address, data is gathered from a data storage location, and a next entry of the list is accessed. Based on the entry of the list indicating that the address is an address of a next entry of the list, the next entry of the list is obtained from another storage location that is located non-contiguously to the entry storage location.

A computer program product, apparatus, and a method for facilitating input/output (I/O) processing for an I/O operation at a host computer system configured for communication with a control unit. The method includes receiving, by a control unit, a command block configured to hold a plurality of commands including an input command and/or an output command, the plurality of commands specified by a transport command word (TCW) including a read indicator configured to indicate whether the I/O operation includes input data and a write indictor configured to indicate whether the I/O operation includes output data; based on the command block holding at least one output command, receiving the output data and executing the at least one output command; and based on the command block holding at least one input command, forwarding the input data to the channel subsystem for storage at a location specified by the TCW.

Bi-directional data transfer within a single I/O operation

An computer program product, apparatus, and method for facilitating input/output (I/O) processing for an I/O operation at a host computer system configured for communication with a control unit. The computer program product is provided for performing a method including: sending a transport command word (TCW) to an I/O subsystem, the TCW specifying a location address and indicating whether the TCW directly or indirectly addresses a message; extracting the location address from the TCW; obtaining the message from the specified location address based on the TCW indicating direct addressing, the message including the one or more I/O commands; gathering the one or more I/O commands from command locations specified by a list of addresses identified by the specified location address to form the message based on the TCW indicating indirect addressing; and generating a message including the one or more I/O commands.

Providing indirect data addressing for a control block at a channel subsystem of an I/O processing system

An adapter is enabled for use. The enabling includes assigning one or more address spaces to the adapter, based on a request. For each address space assigned to the adapter, a corresponding device table entry is assigned. When the adapter is no longer needed, it is disabled and the assigned device table entries become available.

Enable/disable adapters of a computing environment

A method includes configuring a processing circuit to perform: receiving a control word for an I/O operation, forwarding a transport command control block (TCCB) from the channel subsystem to a control unit, gathering data associated with the I/O operation, and transmitting the gathered data to the control unit in the I/O processing system. Gathering the data includes accessing entries of a list of storage addresses that collectively specifying the data. Based on an entry of the list comprising a not-set first flag and a corresponding first storage address, gathering data from a corresponding storage location, and based on an entry of the list comprising a set first flag and a corresponding second storage address, obtaining a next entry of the list from a second storage location.

A computer program product, apparatus, and a method for facilitating input/output (I/O) processing for an I/O operation at a host computer system configured for communication with a control unit. The method includes receiving a command block from the channel subsystem, the command block including at least one input command and at least one output command specified by a transport command word (TCW) and associated with the I/O operation, the I/O operation having both input and output data, the TCW specifying a location in the memory of the output data and a location in the memory for storing the input data; receiving the output data specified by the TCW and executing the at least one output command; and forwarding the input data specified by the TCW to the channel subsystem for storage at a location specified by the TCW.

An computer program product, apparatus, and method for facilitating input/output (I/O) processing for an I/O operation at a host computer system configured for communication with a control unit. The computer program product is provided for performing a method including: obtaining a transport command word (TCW) for an I/O operation, the TCW specifying a location address and indicating whether the TCW directly or indirectly addresses a message for transmitting one or more commands to the control unit; extracting the specified location address from the TCW; obtaining the message from the specified location address based on the TCW indicating direct addressing, the message including one or more I/O commands; gathering one or more I/O commands from command locations specified by a list of addresses identified by the specified location address to form the message based on the TCW indicating indirect addressing; and forwarding the message to the control unit for execution.

A tiered discovery capability is employed to obtain attributes regarding adapters of an I/O configuration. The first tier obtains a list of the adapter functions accessible to an operating system; the second tier obtains attributes regarding a selected adapter function of the list of adapter functions; and a third tier obtains common attributes of a group of adapter functions, the group including the selected adapter function.

Discovery by operating system of information relating to adapter functions accessible to the operating system

An computer program product, apparatus, and method for facilitating input/output (I/O) processing for an I/O operation at a host computer system configured for communication with a control unit. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes the host computer system obtaining a transport command word (TCW) for an I/O operation. The TCW specifies a location of one or more I/O commands and a flag set to indicate that the location is an indirect address. The host computer system extracts the location of the one or more I/O commands and the flag from the TCW, gathers the one or more I/O commands responsive to the location specified by the TCW and the flag, and then forwards the one or more I/O commands to the control unit for execution.

Detection, notification and/or processing of events, such as errors associated with adapters, are facilitated. Hardware detects an event, places one or more adapters in an error state to prevent access to/from the adapters, and notifies the operating system of the event.

Managing processing associated with hardware events

Notification of hardware actions to be taken responsive to hardware events is facilitated. An operating system coupled, but external to, the hardware notifies firmware of the hardware action to be taken.

Operating system notification of actions to be taken responsive to adapter events

An article of manufacture, apparatus, and a method for facilitating input/output (I/O) processing for an I/O operation at a host computer system configured for communication with a control unit. The method includes the host computer system obtaining a transport command word (TCW) for an I/O operation having both input and output data. The TCW specifies a location of the output data and a location for storing the input data. The host computer system forwards the I/O operation to the control unit for execution. The host computer system gathers the output data responsive to the location of the output data specified by the TCW, and then forwards the output data to the control unit for use in the execution of the I/O operation. The host computer system receives the input data from the control unit and stores the input data at the location specified by the TCW.

Systems, methods and computer program products for providing indirect data addressing at an I/O subsystem of an I/O processing system. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes receiving a control word for an I/O operation. The control word includes an indirect data address for data associated with the I/O operation. The indirect data address includes a starting location of a list of storage addresses that collectively specify the data, the list spans two or more non-contiguous storage locations. Data is gathered responsive to the list. The gathered data is transmitted to a control unit in the I/O processing system.

The state of an input/output (I/O) operation is determined in an I/O processing system. A command is received from an I/O operating system at a channel subsystem for initiating the I/O operation, a time period is for completion of the I/O operation, and the command for initiating the I/O operation is sent from the channel subsystem to the control unit. Responsive to the time period nearing elapsing without the I/O operation completing, a cancel instruction is received from the I/O operating system at the channel subsystem. Responsive to a determination by the I/O operating system to interrogate the control unit, an instruction to interrogate the control unit is received with the cancel instruction from the I/O operating system.

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Yonkers, NY, United States of America

Ugochukwu Charles Njoku