Magnetic Disk Device Write Current Synchronization
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Solution Overview
Problem
Magnetic disk devices without data-dependent write (DDW) function output a uniform write current, leading to inefficiencies in data writing, while those with DDW require synchronization of write current changes based on data patterns, complicating signal synchronization.
Innovation Solution
A method for a magnetic disk device that includes adding a delay to the polarity inversion timing of write data or control signals, synchronizing the write current output with these signals, and adjusting deviations between write data and control signals to improve data write reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data-dependent write (DDW) function is implemented to change write current according to data pattern, then write efficiency and data integrity are improved, but signal synchronization complexity increases
Solution Approach 1:
The patent applies preliminary action by adding delay to the polarity inversion timing of write data or control signals before they reach the head amplifier IC. This advance timing adjustment ensures that write current changes are properly synchronized with data patterns, resolving the synchronization complexity issue while maintaining DDW functionality and data write reliability
Solution Approach 2:
The patent changes the timing parameter of the control signal or write data by adding a delay to the polarity inversion timing. This parameter adjustment allows the write current to be synchronized with the data pattern without requiring complex synchronization circuitry, thus improving reliability while managing complexity
2Device complexity
If uniform write current is output without DDW function, then device complexity is reduced, but write efficiency and data integrity deteriorate
Solution Approach 1:
By adding delay to the polarity inversion timing in advance, the system achieves proper synchronization between write current and data patterns without requiring complex real-time synchronization mechanisms, thus maintaining simplicity while improving write reliability
Solution Approach 2:
The system changes the timing parameter of write data or control signals to achieve synchronized write current output. This simple parameter adjustment enables DDW functionality to improve data write reliability while keeping the device structure relatively simple
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
This approach enhances the reliability of data write operations by accurately synchronizing write currents with data patterns, improving write characteristics and data integrity.
Implementation Method 1
a head that writes data on the disk
Data Source
AI summary
An adjusting method for a magnetic disk device including a disk, a head that writes data on the disk, a controller circuit that outputs write data and a control signal related to the write data, and an integrated circuit that outputs a write current to the head, includes adding a delay to a timing of polarity inversion of one bit of the write data or the control signal, outputting the write data and the control signal added with the delay from the controller circuit to the integrated circuit, outputting from the integrated circuit to the head, the write current having a current value that is changed at one of timings of polarity inversion of the write data, according to the control signal, and adjusting a deviation between the write data and the control signal, based on the output write current.