摘要:
A computer program product, an apparatus, and a method for processing communications between a control unit and a channel subsystem in an input/output 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: sending a command from the channel subsystem to the control unit to initiate an input/output operation; setting a time period for completion of the operation; and responsive to the operation not completing within the time period, sending a message to determine whether the control unit has an exchange open for the command.
摘要:
Input/output processing is facilitated by readily enabling access to information associated with input/output processing. This information includes status information and measurement data provided by a control unit executing input/output commands. The status and measurement data are provided in a status control block identified in a transport control word, which is further used to specify a location in memory that includes the input/output commands to be executed.
摘要:
An encryption method encrypts a clear text twice using a first encryption engine to produce a first cipher text and a second encryption engine to produce a second cipher text. The method compares the first cipher text with the second cipher text, or compares a checksum of the first cipher text with a checksum of the second cipher text. If the comparison succeeds, the method transmits the data. In some embodiments, the method uses a first instance of an encryption key to produce the first cipher text and a second instance of the encryption key to produce the second cipher text.
摘要:
A device control unit operating under the protocol of a parallel bus is connected by a serial link to a channel that is primarily adapted to operate under a different protocol with device control units connected by a serial link. An extender unit interconnects the parallel bus and the serial link and performs the specific operations of the parallel bus protocol. The channel and the extender unit send serial frames on the link for data transfer and associated operations. These frames are constructed according to a protocol that provides an intermediate step in translating between the protocol of the serial control units and the protocol of the parallel control units. The channel is operable in either mode (by microcode) and the new protocol permits the serial channel mode to be independent of the protocol of the parallel control unit and it permits the two modes to be closely similar in many features. New operations using the protocol reduce the delays that would otherwise be required in the communications between the channel and the extender unit. The serial link can be made longer when the delays are reduced.
摘要:
A computer program product is provided for performing input/output (I/O) processing. The computer program product is configured to perform: 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 discard field; generating an address control structure specifying a local channel memory location of a corresponding ACW; receiving one or more data transfer requests from a network interface that each corresponding address control structure information; accessing an ACW and routing the data transfer request to a host memory location specified in the ACW; and responsive to encountering an error during at least one of the accessing and the routing, discarding the one or more data transfer requests and setting the data discard field to a value configured to instruct a channel to discard any subsequent data transfer requests associated with the ACW.
摘要:
A method for detecting virtual images in a network, the network including a host system and a plurality of physical devices in operable communication with one another, includes forming a query packet at the host system; providing the query packet to at least one of the plurality of physical devices; forming at the at least of the plurality of physical devices a first vector in response to the query packet, the first vector including a bit for each possible virtual image that may be formed in the at least one of the plurality of devices and indicating which of the virtual images are configured and addressable; and providing the first vector to the host system.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.