I/O Suspension Message Protocol for Link Stability
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Solution Overview
Problem
Current link protocols lack the ability to exchange operating parameters between the channel and the control unit, leading to errors and potential loss of logical paths due to the reliance on busy messages for suspending I/O operations.
Innovation Solution
A method and system for processing communications between an initiator and a target in an input/output processing system, allowing for the suspension of I/O operations by sending a message requesting a defined period of suspension, enabling the exchange of operating parameters and determining protocol compatibility between the channel and control unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current link protocols are used to suspend I/O operations, then the control unit can request suspension, but errors and loss of logical paths occur due to reliance on busy messages
Solution Approach 1:
The patent introduces a dedicated suspension request message as an intermediary mechanism between the control unit and channel. This message serves as a formal protocol element that mediates the suspension request, replacing the problematic busy message approach. The suspension request message carries explicit suspension intent and timing information, enabling reliable coordination without causing logical path loss.
Solution Approach 2:
The patent changes the protocol parameter from using generic busy messages to using a specific suspension request message with defined parameters including suspension duration. This parameter change allows the channel to understand the exact nature and duration of the suspension request, eliminating the ambiguity that causes errors in the busy message approach.
2Reliability
If the channel ceases sending new commands or the control unit responds with busy messages to suspend operations, then suspension is achieved, but system complexity increases and operations become less efficient
Solution Approach 1:
The patent segments the I/O operation control into distinct protocol elements: normal command flow, suspension request messages, and resumption protocols. By segmenting the control mechanism into specific message types with defined purposes, the system achieves reliable suspension control without requiring complex ad-hoc handling of busy messages and conditional cease operations.
3Adaptability or versatility
If no link protocol allows exchange of operating parameters, then existing protocols can be maintained, but the control unit cannot request suspension for a selected period of time
Solution Approach 1:
The patent extends the link protocol to serve multiple functions: normal command transmission, operating parameter exchange, and suspension request handling. The suspension request message acts as a multi-functional protocol element that can convey both the suspension intent and the duration parameter, enabling the control unit to request time-bound suspensions while maintaining protocol universality.
Data Source
AI summary
A computer program product, an apparatus, and a method for processing communications between a target and an initiator 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 message between the initiator and the target, the message requesting suspension of input/output operations between the initiator and the target for a period of time, the period of time being defined by the message; and responsive to the message, suspending input/output operation messages for the period of time.