Flaw Scan Circuit for RRO Data Integrity
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Solution Overview
Problem
Existing flaw scan circuits in magnetic recording systems fail to accurately detect low quality RRO data due to false RRO address marks caused by noise, leading to insufficient capture of low quality samples and improper flag setting.
Innovation Solution
The proposed solution involves counting RRO data bits in servo sectors and setting an RRO flaw flag if a specified number is not detected, and also detecting RRO address marks to count samples that do not satisfy a quality threshold, setting the flag when the count exceeds a threshold, while utilizing the expected number of RRO data bits to set the flag if not recovered by the servo channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the flaw scan circuit counts low quality samples after detecting the RRO address mark, then the flag setting is simplified, but false RRO address marks caused by noise lead to insufficient capture of low quality samples
Solution Approach 1:
The patent applies preliminary action by counting the total number of RRO data bits expected in the servo sector before processing begins. This pre-established expectation value serves as a reference to detect whether the actual number of valid RRO data bits matches the expected count, thereby preventing false flag settings due to noise-induced false RRO address marks while maintaining simple circuit operation.
2Ease of operation
If the flaw scan circuit sets a flag when the number of low quality samples exceeds a threshold, then the error detection is straightforward, but false RRO address marks cause improper flag setting
Solution Approach 1:
The patent implements feedback by comparing the actual number of detected RRO data bits against the expected number of RRO data bits. This feedback mechanism allows the system to detect discrepancies caused by false RRO address marks and adjust the flag setting accordingly, improving measurement precision while maintaining ease of operation through a straightforward comparison process.
3Measurement precision
If the flaw scan circuit starts counting low quality samples after detecting the RRO address mark, then the counting begins at the correct position, but false RRO address marks towards the end of servo processing gate result in insufficient sample capture
Solution Approach 1:
The patent applies preliminary action by pre-determining the expected number of RRO data bits and using this information to validate the entire RRO data field. This approach ensures that even if false RRO address marks appear towards the end of the servo processing gate, the system can still accurately capture and count all low quality samples by referencing the pre-established expected bit count.
Data Source
AI summary
Improved flaw scan circuits are provided for repeatable run out data. RRO (repeatable run out) data is processed by counting a number of RRO data bits detected in a servo sector; and setting an RRO flaw flag if at least a specified number of RRO data bits is not detected in the server sector. The RRO flaw flag can also optionally be set by detecting an RRO address mark in the servo sector; counting a number of samples in the servo sector after the RRO address mark that do not satisfy a quality threshold; and setting the RRO flaw flag when the counted number of samples that do not satisfy the quality threshold exceeds a specified flaw threshold. If the RRO flaw flag is set, the RRO data can be discarded, and/or an error recovery mechanism can be implemented to obtain the RRO data.