FACILITATING TRANSPORT MODE INPUT/OUTPUT OPERATIONS BETWEEN A CHANNEL SUBSYSTEM AND INPUT/OUTPUT DEVICES
First Claim
1. A non-transitory computer readable medium comprising executable instructions for performing an input/output (I/O) operation at a control unit configured to control an I/O device and configured for communication with a host computer system, the I/O operation initiated by an I/O operation instruction, the computer readable medium readable by a processing circuit for performing a method comprising:
- receiving at least one command message specifying an I/O operation at the control unit from a channel subsystem of the host computer system, the at least one command message including one or more device command words (DCWs), each DCW specifying an I/O command, wherein at least one DCW of the one or more DCWs includes a data count and a suppress-length indication (SLI), the SLI configured to instruct the control unit whether to continue to perform the I/O operation based on the control unit detecting an incorrect length condition, the incorrect length condition detected based on the data count not matching an amount of data required to perform the I/O operation command, wherein the data required is one of data available at the control unit for a read operation command and data required by the control unit for a write operation command;
processing at least one of the one or more DCWs; and
returning a transport response message by the control unit to the channel subsystem based on executing or terminating the I/O operation, the transport response message including a status of the I/O operation and an incorrect length (IL) value indicating presence or absence of the incorrect length condition, the IL value being a first IL value based on the SLI being a first SLI value and the data count not matching the amount of data required, the IL value being a second IL value based on the SLI being the first SLI value and the data count matching the amount of data required, the transport response message including at least one residual count field configured to indicate at least one of;
i) a difference between the data count and an amount of data received from the channel subsystem and ii) a difference between the data count and an amount of data sent to the channel subsystem.
2 Assignments
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Accused Products
Abstract
A computer program product is configured for performing a method including: receiving at least one command message specifying an I/O operation at a control unit from a channel subsystem, the at least one command message including one or more device command words (DCWs) having a data count and a suppress-length indication (SLI), the SLI configured to instruct the control unit whether to continue to perform the I/O operation in response to the control unit detecting an incorrect length condition; processing at least one of the one or more DCWs; and returning a transport response message including 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, the IL value being a second IL value in response to the SLI being a second SLI value and the data count not matching the amount of data required.
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Citations
27 Claims
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1. A non-transitory computer readable medium comprising executable instructions for performing an input/output (I/O) operation at a control unit configured to control an I/O device and configured for communication with a host computer system, the I/O operation initiated by an I/O operation instruction, the computer readable medium readable by a processing circuit for performing a method comprising:
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receiving at least one command message specifying an I/O operation at the control unit from a channel subsystem of the host computer system, the at least one command message including one or more device command words (DCWs), each DCW specifying an I/O command, wherein at least one DCW of the one or more DCWs includes a data count and a suppress-length indication (SLI), the SLI configured to instruct the control unit whether to continue to perform the I/O operation based on the control unit detecting an incorrect length condition, the incorrect length condition detected based on the data count not matching an amount of data required to perform the I/O operation command, wherein the data required is one of data available at the control unit for a read operation command and data required by the control unit for a write operation command; processing at least one of the one or more DCWs; and returning a transport response message by the control unit to the channel subsystem based on executing or terminating the I/O operation, the transport response message including a status of the I/O operation and an incorrect length (IL) value indicating presence or absence of the incorrect length condition, the IL value being a first IL value based on the SLI being a first SLI value and the data count not matching the amount of data required, the IL value being a second IL value based on the SLI being the first SLI value and the data count matching the amount of data required, the transport response message including at least one residual count field configured to indicate at least one of;
i) a difference between the data count and an amount of data received from the channel subsystem and ii) a difference between the data count and an amount of data sent to the channel subsystem. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An apparatus for performing an input/output (I/O) operation at a control unit configured to control an I/O device and configured for communication with a host computer system, the I/O operation initiated by an I/O operation instruction, the control unit configured to perform:
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receiving at least one command message specifying an I/O operation at the control unit from a channel subsystem of the host computer system, the at least one command message including one or more device command words (DCWs), each DCW specifying an I/O command, wherein at least one DCW of the one or more DCWs includes a data count and a suppress-length indication (SLI), the SLI configured to instruct the control unit whether to continue to perform the I/O operation based on in the control unit detecting an incorrect length condition, the incorrect length condition detected based on the data count not matching an amount of data required to perform the I/O operation command, wherein the data required is one of data available at the control unit for a read operation command and data required by the control unit for a write operation command; processing at least one of the one or more DCWs; and returning a transport response message by the control unit to the channel subsystem based on executing or terminating the I/O operation, the transport response message including a status of the I/O operation and an incorrect length (IL) value indicating presence or absence of the incorrect length condition, the IL value being a first IL value based on the SLI being a first SLI value and the data count not matching the amount of data required, the IL value being a second IL value based on the SLI being the first SLI value and the data count matching the amount of data required, the transport response message including at least one residual count field configured to indicate at least one of;
i) a difference between the data count and an amount of data received from the channel subsystem and ii) a difference between the data count and an amount of data sent to the channel subsystem. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 26)
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20. A method of performing an input/output (I/O) processing operation at a control unit configured to control an I/O device and configured for communication with a host computer system, the I/O operation initiated by an I/O operation instruction, the method comprising:
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receiving at least one command message specifying an I/O operation at the control unit from a channel subsystem of the host computer system, the at least one command message including one or more device command words (DCWs), each DCW specifying an I/O command, wherein at least one DCW of the one or more DCWs includes a data count and a suppress-length indication (SLI), the SLI configured to instruct the control unit whether to continue to perform the I/O operation based on the control unit detecting an incorrect length condition, the incorrect length condition detected based on the data count not matching an amount of data required to perform the I/O operation command, wherein the data required is one of data available at the control unit for a read operation command and data required by the control unit for a write operation command; processing at least one of the one or more DCWs; and returning a transport response message by the control unit to the channel subsystem based on executing or terminating the I/O operation, the transport response message including a status of the I/O operation and an incorrect length (IL) value indicating presence or absence of the incorrect length condition, the IL value being a first IL value based on the SLI being a first SLI value and the data count not matching the amount of data required, the IL value being a second IL value based on the SLI being the first SLI value and the data count matching the amount of data required, the transport response message including at least one residual count field configured to indicate at least one of;
i) a difference between the data count and an amount of data received from the channel subsystem and ii) a difference between the data count and an amount of data sent to the channel subsystem. - View Dependent Claims (21, 22, 23, 24, 25, 27)
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Specification