Channel Subsystem Data Logout Command for FICON Debugging

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Solution Overview

Problem

Debugging FICON channel-to-channel connections is challenging due to the involvement of two channels, and existing mechanisms cannot signal a remote channel to log out across a physical link, making it difficult to diagnose and log errors in a non-disruptive manner.

Innovation Solution

A method and system for generating a data logout command across a channel-to-channel connection, where a processor issues a logout command to the input/output subsystem, which sends it to the channel control unit, allowing for a non-disruptive log to be taken regardless of whether the control unit function resides on the local or remote channel, using a new 'sense-type' command invoked during error conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If a non-disruptive logout command is issued across a channel-to-channel connection, then error diagnosis capability is improved, but the complexity of the logging mechanism increases

Engineering Contradiction:

Improveerror diagnosis capabilityVSAvoidlogging mechanism complexity

Core Design Contradiction:

Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary logout command mechanism that mediates between the local channel and remote channel. The logout command acts as a mediator to trigger logging on the remote channel without requiring direct complex interaction between the two channels, simplifying the overall system while improving error diagnosis capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary action by issuing a logout command before actual error conditions occur or at the moment of error detection. This preliminary logout command ensures that the remote channel is prepared to log relevant state information, enabling proactive error diagnosis rather than reactive analysis.

Inventive Principle:

Principle #10Preliminary action

2Loss of information

If a logout command is sent across the physical link to the remote channel, then logging coverage is improved, but the communication overhead increases

Engineering Contradiction:

Improvelogging coverageVSAvoidcommunication overhead

Core Design Contradiction:

Loss of informationVSLoss of time

Solution Approach 1:

The patent extracts the logging function from the normal channel communication flow and separates it into a distinct logout command mechanism. This extraction allows the logging operation to be performed independently without interfering with the primary data transmission functions, minimizing communication overhead while maintaining comprehensive logging coverage.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The remote channel performs self-service by automatically generating and maintaining its own state information upon receiving the logout command. This self-service capability eliminates the need for the local channel to continuously query or synchronize with the remote channel, reducing communication overhead while ensuring complete logging coverage.

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If the control unit function is located on the remote channel, then system flexibility is improved, but the ability to log local channel state deteriorates

Engineering Contradiction:

Improvesystem flexibilityVSAvoidlocal channel state logging

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent applies inversion by reversing the traditional approach where the controlling channel logs its own state. Instead, the local channel issues a logout command that triggers the remote channel (which has control unit function) to log the state. This inverted mechanism allows the controlling channel to log the state of the other channel, providing complete visibility while maintaining system flexibility.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS7600056B2Method for generating a data logout in a computing environment

Publication Date: 2009.10.06 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

A method and system are disclosed for generating a data logout in a computing environment having a processor and an input/output subsystem for receiving data from and sending data to the processor. The method comprises the steps of the input/output subsystem maintaining a defined set of data; at defined time, the processor issuing a data logout command; and sending said data logout command to the input/output subsystem. In response to receiving said data logout command, the input/output subsystem sends said defined set of data to a specified location. In a preferred implementation, the input/output subsystem includes a channel subsystem and a plurality of input/output devices, and the data logout command is sent to one of the input/output devices. Also, in the preferred embodiment, the channel subsystem includes a channel control unit function and the data logout command is sent to the channel control unit function.