Transport control channel program chain linked branching
First Claim
1. A computer program product for processing a transport control channel program with chain linked branching at a control unit configured for communication with an input/output (I/O) subsystem in an I/O processing system, the computer program product comprising:
- a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising;
receiving a login request message;
transmitting a login accept message in response to the login request message, the login accept message including a maximum linked commands field indicating a maximum count of additional command messages after a first command message that the control unit supports;
receiving a command message at the control unit from the I/O subsystem to perform an I/O operation, wherein the received command message is one of the first command message and the additional command messages;
reading a chain linked flag in the received command message, the chain linked flag indicating that a subsequent command message for the I/O operation follows the received command message;
reading a serialization flag in the received command message, the serialization flag requesting that device status be returned to the I/O subsystem in order to select the subsequent command message;
executing one or more commands in the received command message; and
transmitting the device status to the I/O subsystem in response to executing the one or more commands in combination with the serialization flag.
1 Assignment
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Accused Products
Abstract
A computer program product, apparatus, and method for processing a transport control channel program with chain linked branching in an I/O processing system are provided. The method includes receiving a command message at a control unit from an I/O subsystem to perform an I/O operation. The method further includes reading a chain linked flag in the command message indicating that a subsequent command message for the I/O operation follows the command message. The method also includes reading a serialization flag in the command message requesting that device status be returned to the I/O subsystem in order to select the subsequent command message. The method additionally includes executing one or more commands in the command message, and transmitting the device status to the I/O subsystem in response to executing the one or more commands in combination with the serialization flag.
133 Citations
28 Claims
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1. A computer program product for processing a transport control channel program with chain linked branching at a control unit configured for communication with an input/output (I/O) subsystem in an I/O processing system, the computer program product comprising:
a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising; receiving a login request message; transmitting a login accept message in response to the login request message, the login accept message including a maximum linked commands field indicating a maximum count of additional command messages after a first command message that the control unit supports; receiving a command message at the control unit from the I/O subsystem to perform an I/O operation, wherein the received command message is one of the first command message and the additional command messages; reading a chain linked flag in the received command message, the chain linked flag indicating that a subsequent command message for the I/O operation follows the received command message; reading a serialization flag in the received command message, the serialization flag requesting that device status be returned to the I/O subsystem in order to select the subsequent command message; executing one or more commands in the received command message; and transmitting the device status to the I/O subsystem in response to executing the one or more commands in combination with the serialization flag. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for processing a transport control channel program with chain linked branching at a control unit in an I/O processing system, the apparatus comprising:
a control unit configured for communication with an I/O subsystem of the I/O processing system, the control unit configured to perform a method comprising; receiving a login request message; transmitting a login accept message in response to the login request message, the login accept message including a maximum linked commands field indicating a maximum count of additional command messages after a first command message that the control unit supports; receiving a command message at the control unit from the I/O subsystem to perform an I/O operation, wherein the received command message is one of the first command message and the additional command messages; reading a chain linked flag in the command message, the chain linked flag indicating that a subsequent command message for the I/O operation follows the received command message; reading a serialization flag in the received command message, the serialization flag requesting that device status be returned to the I/O subsystem in order to select the subsequent command message; executing one or more commands in the received command message; and transmitting the device status to the I/O subsystem in response to executing the one or more commands in combination with the serialization flag. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method for processing a transport control channel program with chain linked branching at a control unit configured for communication with an input/output (I/O) subsystem in an I/O processing system, the method comprising:
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receiving a command message at the control unit from the I/O subsystem to perform an I/O operation; reading a chain linked flag in the command message, the chain linked flag indicating that a subsequent command message for the I/O operation follows the received command message; reading a serialization flag in the command message, the serialization flag requesting that device status be returned to the I/O subsystem in order to select the subsequent command message; executing one or more commands in the received command message; in response to determining that the subsequent command message is expected in response to the chain linked flag, continuing to run counters associated with the I/O operation to span the received command message and the subsequent command message; and transmitting the device status to the I/O subsystem in response to executing the one or more commands in combination with the serialization flag. - View Dependent Claims (16)
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17. A computer program product for processing a transport control channel program with chain linked branching at a channel subsystem configured for communication with a control unit in an I/O processing system, the computer program product comprising:
a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising; transmitting a login request message including a channel maximum linked commands field indicating a maximum count of additional command messages queued after a command message that the channel subsystem supports; receiving a login accept message in response to the login request message, the login accept message including a control unit maximum linked commands field indicating a maximum count of additional command messages queued after the command message that the control unit supports; limiting transmissions to the control unit to comply with the control unit maximum linked commands field; configuring a chain linked flag in a command message to indicate that a subsequent command message follows a first command message to perform an I/O operation; configuring a serialization flag in the first command message to request that device status be returned to the channel subsystem in order to select the subsequent command message; and transmitting the first command message from the channel subsystem to the control unit. - View Dependent Claims (18, 19, 20)
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21. An apparatus for processing a transport control channel program with chain linked branching at a channel subsystem in an I/O processing system, the apparatus comprising:
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a channel subsystem configured for communication with a control unit of the I/O processing system, the channel subsystem configured to perform a method comprising; transmitting a login request message including a channel maximum linked commands field indicating a maximum count of additional command messages queued after a command message that the channel subsystem supports; receiving a login accept message in response to the login request message, the login accept message including a control unit maximum linked commands field indicating a maximum count of additional command messages queued after the command message that the control unit supports; limiting transmissions to the control unit to comply with the control unit maximum linked commands field; configuring a chain linked flag in a command message to indicate that a subsequent command message follows a first command message to perform an I/O operation; configuring a serialization flag in the first command message to request that device status be returned to the channel subsystem in order to select the subsequent command message; and transmitting the first command message from the channel subsystem to the control unit. - View Dependent Claims (22, 23, 24)
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25. A method of processing a transport control channel program with chain linked branching at a channel subsystem configured for communication with a control unit of an I/O processing system, the method comprising:
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transmitting a login request message including a channel maximum linked commands field indicating a maximum count of additional command messages queued after a command message that the channel subsystem supports; receiving a login accept message in response to the login request message, the login accept message including a control unit maximum linked commands field indicating a maximum count of additional command messages queued after the command message that the control unit supports; limiting transmissions to the control unit to comply with the control unit maximum linked commands field; configuring a chain linked flag in a first command message to indicate that a subsequent command message follows the command message to perform an I/O operation; configuring a serialization flag in the first command message to request that device status be returned to the channel subsystem in order to select the subsequent command message; and transmitting the first command message from the channel subsystem to the control unit. - View Dependent Claims (26, 27, 28)
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Specification