Magnetic Disk Controller Pseudo Polarity Inversion Data Pattern Conversion
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Solution Overview
Problem
Magnetic disk devices using pulse-based writing methods face challenges in maintaining recording quality due to bit error rates and polarity inversions when converting specific data patterns, which affect the reliability of data written to disks.
Innovation Solution
A magnetic disk device with a system that includes a head, a preamplifier, and a controller to convert data patterns by generating a recording current without causing polarity inversion, using a pattern conversion table to adjust the data pattern length and pseudo polarity inversion, thereby improving recording quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If data pattern conversion is performed using pulse-based writing method, then recording current waveform control is improved, but polarity inversion errors occur affecting recording quality
Solution Approach 1:
The system performs preliminary analysis of the data pattern before conversion to identify patterns that would cause polarity inversion errors. By detecting these problematic patterns in advance and applying appropriate conversion rules from the conversion table, the system prevents recording quality degradation before it occurs.
Solution Approach 2:
The system changes the parameters of the recording current waveform based on the detected data pattern. By selecting different waveform parameters from the conversion table corresponding to specific data patterns, the system optimizes the recording current characteristics to avoid polarity inversion errors and improve recording quality.
2Manufacturing precision
If data pattern conversion is performed to prevent polarity inversion, then recording quality is improved, but device complexity increases due to conversion tables and pattern analysis
Solution Approach 1:
The system uses a conversion table that stores pre-defined conversion rules for different data patterns. Instead of implementing complex real-time analysis logic, the system copies and applies established conversion rules from the table, simplifying the device structure while maintaining effective pattern conversion capability.
3Productivity
If pulse-based writing method is used with waveform control, then data writing speed is improved, but polarity inversion causes bit error rates to increase
Solution Approach 1:
The system incorporates feedback by analyzing the output data pattern after conversion to detect polarity inversion errors. When errors are detected, the system adjusts the conversion rules applied to subsequent patterns, creating a feedback loop that continuously improves recording reliability while maintaining writing speed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances recording quality by optimizing bit error rates and reducing the impact of polarity inversions, leading to improved data reliability and efficiency in writing data to disks.
Implementation Method 1
a head to write data to a disk and read data from the disk; a preamplifier to generate a recording current corresponding to data that the head writes to the disk
Data Source
AI summary
According to one embodiment, a magnetic disk device, including a disk, a head to write data to the disk and read data from the disk, a preamplifier to generate a recording current corresponding to data that the head writes to the disk, and a controller to convert a first data pattern in first write data, in accordance with a pattern length of a second data pattern previous to the first data pattern, to a different data pattern including a pseudo polarity inversion that does not cause a polarity inversion when converting the first data pattern to the recording current.