Transport Control Word Consolidates I/O Commands
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Solution Overview
Problem
Current input/output processing methods require multiple exchanges and sequences between the channel and control unit, necessitating individual tracking of command status, which increases communication overhead and reduces efficiency.
Innovation Solution
The introduction of a transport control word that consolidates multiple channel command words into a single entity, allowing the control unit to execute commands independently without tracking individual command states, thereby reducing the number of exchanges and sequences required during input/output processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple channel command words are sent individually to the control unit, then the control unit can execute commands with proper state tracking, but the communication overhead between channel and control unit increases
Solution Approach 1:
The patent combines multiple channel command words into a single transport control word structure that includes a command list. This merging reduces the number of separate communications between the channel and control unit while maintaining the ability to track and execute multiple commands reliably. The transport control word consolidates what would otherwise require multiple individual command transmissions.
2Loss of information
If the channel tracks the state of each individual command, then command execution status can be monitored, but the workload on the channel subsystem increases
Solution Approach 1:
The patent extracts the command state tracking function from the channel subsystem and relocates it to the control unit. The transport control word structure allows the control unit to receive and track the state of multiple commands independently, freeing the channel from the burden of individual command state management while preserving complete status information.
3Ease of operation
If multiple exchanges and sequences are used between channel and control unit, then individual command processing can be maintained, but processing efficiency decreases
Solution Approach 1:
The patent merges multiple command transmissions into a single exchange by introducing the transport control word that encapsulates a list of channel command words. This consolidation reduces the number of exchanges and sequences required between the channel and control unit, thereby improving I/O processing efficiency while maintaining proper command processing control through the structured command list.
Data Source
AI summary
A computer program product, apparatus, and method for facilitating input/output processing of a processing environment are provided. The computer program product is provided for performing a method including: obtaining by an input/output communications adapter of the processing environment a transport control word including an address of a channel command word descriptor configured to contain a plurality of commands to be executed by the control unit; forwarding to the control unit the channel command word descriptor that includes one or more commands as one entity, wherein the forwarding includes forwarding from the input/output communications adapter to the control unit the channel command word descriptor including the one or more commands in a single communication; and receiving the ending status by the input/output communications adapter absent a tracking of state of individual commands by the input/output communications adapter, the ending status comprising timing information associated with the one or more commands.