Abstract: A computer program product for performing input/output (I/O) processing is provided. The computer program product is configured to perform: obtaining information relating to an I/O operation at a channel subsystem; generating and storing in local channel memory at least one address control word (ACW) specifying one or more host memory locations for data transfer and including a data check word generation field and/or a data check word save field; responsive to receiving an input data transfer request including at least one data check word, storing the at least one data check word in the data check word save field and performing a check of the data to determine whether the data has been corrupted; and responsive to receiving an output data transfer, generating at least one data check word based on the data check word generation field and appending the at least one data check word to the data.

Abstract: An input/output processing method includes generating and storing at least one address control word (ACW) including a data check word generation field and/or a data check word save field in local channel memory of a channel subsystem, and generating and forwarding to a network interface an address control structure specifying a location in the local channel memory of a corresponding ACW. The method also includes, responsive to a data transfer request, storing the at least one data check word in the data check word save field and routing the data to a host memory location specified by the corresponding ACW responsive to performing a check of the data and determining that the data has not been corrupted, or retrieving the data based on the corresponding ACW, generating and appending at least one data check word and routing the data and the at least one data check word to the interface.

Abstract: 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.

Abstract: Processing of out-of-order data transfers is facilitated in computing environments that enable data to be directly transferred between a host bus adapter (or other adapter) and a system without first staging the data in hardware disposed between the host bus adapter and the system. An address to be used in the data transfer is determined, in real-time, by efficiently locating an entry in an address data structure that includes the address to be used in the data transfer.

Abstract: A computer program product is provided for performing an input/output (I/O) processing operation at a host computer system. The computer program product is configured to perform: obtaining a transport command word (TCW) at a channel subsystem for an I/O operation, the TCW including an address of a transport command control block (TCCB) having a transport command area (TCA) configured to hold a first plurality of device command words (DCW) and control data associated with respective DCWs, the first plurality of DCWs including a transfer TCA extension (TTE) DCW that specifies a TCA extension, the TCA extension configured to hold one or more DCWs and control data associated with respective DCWs; gathering the TCCB from one or more locations specified in the TCCB address and transferring the TCCB to the control unit; gathering the TCA extension specified by the TTE DCW; and transferring the TCA extension to the control unit.

Abstract: A method of performing an input/output operation includes: generating by a channel subsystem at least one command message including one or more device command words (DCWs), at least one DCW including a data count and a suppress-length indication (SLI) configured to instruct a control unit whether to continue to perform the I/O operation in response to an incorrect length condition; forwarding the at least one command message to the control unit; receiving an incorrect length (IL) value from the control unit and storing an IL indicator in a subchannel-status word, the IL indicator representing the IL value, the IL value being a first IL value in response to a first SLI value and the data count not matching the amount of data required, the IL value being a second IL value in response to a second SLI value and the data count not matching the amount of data required.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A computer program product, apparatus, and method for determining extended capability of a channel path in an I/O processing system are provided. 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 request to provide a channel path description for a channel path, where the channel path includes a channel coupled to a control unit. The method further includes outputting the channel path description for the channel path in response to the request. The channel path description includes a descriptor indicating that the channel path supports a link protocol for commanding an I/O operation, and an extension support indicator specifying whether the channel path supports an extension to the link protocol.

Abstract: A computer program product is configured for performing a method including: generating at least one command message by a channel subsystem of the host computer system, the at least one command message including one or more device command words (DCWs), wherein at least one DCW of the one or more DCWs includes a suppress-length indication (SLI) configured to instruct a control unit to continue to perform the I/O operation in response to the control unit detecting that the data count does not match an amount of data required; receiving an incorrect length (IL) value, the IL value being a first IL value in response to the SLI being a first SLI value and the data count not matching the amount of data required; and responsive to receiving the IL value from the control unit, storing an IL indicator in a subchannel-status word.

Abstract: A computer program product is provided for performing: obtaining, by a channel subsystem, a transport command word (TCW) specified by an operating system, the TCW comprising an address of a transport services request block (TSRQB) and an address of a transport services response block (TSRSB); obtaining the TSRQB; building at least one command request based on the TSRQB, and sending the at least one command request from the channel subsystem to at least one network entity, the at least one command request including at least one of a fibre-channel generic services (FC-GS) request, a fibre-channel link services (FC-LS) request, and a fibre-channel link-level function (FC-SB) request; receiving a response to the at least one command request from the at least one network entity; and storing the response to the TSRSB based on the address of the TSRSB obtained from the TCW.

Abstract: 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.

Abstract: A computer program product is provided for performing a method including: obtaining information relating to an I/O operation at a channel subsystem in a host computer system; generating at least one address control word (ACW) in the local channel memory specifying one or more host memory locations for transfer of data between the host and a control unit and including at least one ACW error checking field; generating an address control structure specifying a location in the local channel memory of a corresponding ACW and including at least one address control structure error checking field; receiving a data transfer request from the network interface that includes the addressing information; comparing the at least one ACW error checking field to the at least one address control structure error checking field; and, responsive to the fields matching, routing the data transfer request to the host memory location specified in the corresponding ACW.

Abstract: A computer program product is provided for performing input/output (I/O) processing at a host computer system. The computer program product is configured to perform: generating an address control structure for each of a plurality of consecutive data transfer requests specified by an I/O operation, each address control structure specifying a location in the local channel memory of a corresponding address control word (ACW) that includes an Offset field indicating a relative order of a data transfer request; generating and storing in local channel memory at least one ACW specifying one or more host memory locations for the plurality of consecutive data transfer requests and including an Expected Offset field indicating a relative order of an expected data transfer request; receiving a transfer request from the network interface and comparing the Offset field and the Expected Offset field to determine whether the data transfer request has been received in the correct order.

Abstract: A computer program product is configured for performing a method including: generating at least one command message by a channel subsystem of the host computer system, the at least one command message including one or more device command words (DCWs), wherein at least one DCW of the one or more DCWs includes a suppress-length indication (SLI) configured to instruct a control unit to continue to perform the I/O operation in response to the control unit detecting that the data count does not match an amount of data required; receiving an incorrect length (IL) value, the IL value being a first IL value in response to the SLI being a first SLI value and the data count not matching the amount of data required; and responsive to receiving the IL value from the control unit, storing an IL indicator in a subchannel-status word.

Abstract: A computer program product is provided for performing an input/output (I/O) processing operation at a host computer system. The computer program product is configured to perform: obtaining a transport command word (TCW) at a channel subsystem for an I/O operation, the TCW including an address of a transport command control block (TCCB) having a transport command area (TCA) configured to hold a first plurality of device command words (DCW) and control data associated with respective DCWs, the first plurality of DCWs including a transfer TCA extension (TTE) DCW that specifies a TCA extension, the TCA extension configured to hold one or more DCWs and control data associated with respective DCWs; gathering the TCCB from one or more locations specified in the TCCB address and transferring the TCCB to the control unit; gathering the TCA extension specified by the TTE DCW; and transferring the TCA extension to the control unit.

Abstract: A computer program product for procuring information from entities in a network via an Input/Output (I/O) processing system 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, at a channel subsystem, at least one network topology information request from an operating system. The method also includes building at least one command request that includes the at least one network topology information request, and sending the at least one command request from the channel subsystem to at least one network entity. The method further includes receiving a response to the at least one command request from the at least one network entity by the channel subsystem, and forwarding the response from the channel subsystem to the operating system.

Abstract: A computer program product for performing input/output (I/O) processing is provided. The computer program product is configured to perform: obtaining information relating to an I/O operation at a channel subsystem; generating and storing in local channel memory at least one address control word (ACW) specifying one or more host memory locations for data transfer and including a data check word generation field and/or a data check word save field; responsive to receiving an input data transfer request including at least one data check word, storing the at least one data check word in the data check word save field and performing a check of the data to determine whether the data has been corrupted; and responsive to receiving an output data transfer, generating at least one data check word based on the data check word generation field and appending the at least one data check word to the data.

Abstract: A computer program product is provided for performing input/output (I/O) processing at a host computer system. The computer program product is configured to perform: generating an address control structure for each of a plurality of consecutive data transfer requests specified by an I/O operation, each address control structure specifying a location in the local channel memory of a corresponding address control word (ACW) that includes an Offset field indicating a relative order of a data transfer request; generating and storing in local channel memory at least one ACW specifying one or more host memory locations for the plurality of consecutive data transfer requests and including an Expected Offset field indicating a relative order of an expected data transfer request; receiving a transfer request from the network interface and comparing the Offset field and the Expected Offset field to determine whether the data transfer request has been received in the correct order.