Channel Subsystem Bi-Directional Data Transfer via PRLI
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Solution Overview
Problem
Conventional input/output (I/O) processing systems do not support bi-directional data transfer operations, limiting their ability to manage both input and output data within a single I/O operation.
Innovation Solution
A computer program product and apparatus that facilitate bi-directional data transfer by sending a Process Login (PRLI) request to initialize a link between a channel subsystem and a control unit, indicating support for bi-directional data transfer, and executing I/O operations by gathering commands, transferring them to the control unit, and receiving input and output data messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional I/O processing systems process individual operations as either input or output data operations, then the system maintains simple processing logic, but the system cannot support bi-directional data transfer operations
Solution Approach 1:
The patent segments the I/O operation into distinct input data operations and output data operations within a single transport mode command. By dividing the bi-directional transfer into separate command components (input commands and output commands), the system achieves bi-directional capability while maintaining manageable processing logic through structured segmentation of the data flow.
Solution Approach 2:
The patent implements a universal transport mode command structure that can handle both input and output data operations within a single I/O operation. The command format is designed to be multi-functional, accommodating bi-directional data transfer by incorporating both input and output command elements, thereby eliminating the need for separate processing paths for different operation types.
2Productivity
If the system processes input and output data as separate operations, then the processing logic remains simple, but the data transfer efficiency decreases
Solution Approach 1:
The patent merges multiple data transfer operations into a single transport mode I/O operation. By combining input and output data transfers into one unified command structure, the system achieves improved data transfer efficiency through reduced overhead and streamlined processing, while the command structure manages complexity through standardized formatting and clear delineation of operation types.
3Adaptability or versatility
If conventional systems use separate I/O operations for input and output data, then the system architecture remains simple, but the capability to manage both input and output within a single operation is limited
Solution Approach 1:
The patent introduces dynamic command structure elements that allow the channel subsystem to adaptively handle both input and output operations within a single transport mode command. The command format includes dynamic fields that can be configured for input, output, or both operations based on the specific data transfer requirements, enabling flexible bi-directional support while managing subsystem complexity through standardized dynamic elements.
Data Source
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AI summary
A computer program product is provided for performing: sending, by a channel subsystem, a process login (PRLI) request message to the control unit that indicates whether the channel subsystem supports bi-directional data transfer; receiving a PRLI response message from the control unit that indicates whether the control unit supports bi-directional data transfer; gathering a plurality of commands, at least one which specifies an input data transfer and at least one specifying an output data transfer; sending at least one output data message to the control unit including output data to be transferred to the control unit, the output data message associated with the at least one of the plurality of commands specifying an output data transfer; and receiving at least one input message from the control unit including input data to be stored in a main storage of the host computer system.